JP2008031920A - Rotary compressor - Google Patents

Abstract

In a rotary compressor in which a first member and a second member are relatively eccentrically rotated in a pressure contact state, the behavior of the second member is stabilized while the behavior of the second member is stabilized. Reduce friction loss as much as possible to improve operating efficiency.
An oil reservoir (23c) for accumulating lubricating oil is provided on a frame (23) facing the back pressure space (S3). In the oil reservoir (23c), when the behavior of the movable scroll (22) is unstable, an oil supply groove (21d) provided on the sliding surface of the fixed scroll (21) with the movable scroll (22) Leaked lubricant accumulates. In the oil reservoir (23c), there is a lower end portion of the oil discharge pipe (42) of the oil discharge passage (43) communicating with the back pressure space (S3) and the low pressure space (S1) located above the back pressure space (S3). Is positioned.
[Selection] Figure 1

Description

  The present invention relates to a rotary compressor, and particularly relates to improvement of operating efficiency.

  Conventionally, as a compressor for compressing a refrigerant in a refrigeration apparatus or the like, for example, a rotary compressor as disclosed in Patent Document 1 is known. In this type of compressor, the first member and the second member are relatively eccentrically rotated in a pressure contact state in a sealed casing, so that the sucked refrigerant is formed by the first member and the second member. It is configured to compress in a compression chamber and discharge in a high pressure state. Specifically, in the example of Patent Document 1, a fixed scroll as a first member fixed in a casing, and a second member that meshes with the fixed scroll and is connected to a drive mechanism via a drive shaft. The movable scroll is disposed in a recess on the upper surface of the frame located on the back side of the movable scroll, and is connected to an eccentric portion provided at the tip of the drive shaft.

  In the case of the rotary compressor configured as described above, when the refrigerant is compressed in the compression chamber, an internal pressure acts on the first member and the second member constituting the compression chamber. That is, the first member and the second member are separated from each other by the internal pressure of the compression chamber (separation force). Thus, when the first member and the second member are separated from each other by applying a separation force, the airtightness of the compression chamber cannot be sufficiently maintained and the compression efficiency is lowered. A pressing force against the first member is applied to the second member by providing a high-pressure space with a seal ring on the back side of the member or providing a back pressure chamber of intermediate pressure.

  On the other hand, if the second member is pressed too much on the first member side, the frictional resistance between the two members increases and the loss also increases. Therefore, the sliding surface (thrust surface) of the first member with the second member is increased. By forming an oil groove and supplying high pressure oil to the oil groove, the pressure contact force between the first member and the second member is balanced.

Further, in order to balance the pressure contact force between the first member and the second member as described above, for example, as disclosed in Patent Document 1, the pressure in the back pressure space is changed to the refrigerant discharge pressure or the refrigerant. It is known that the pressure in the back pressure space is always kept constant by providing a communication path and a valve between the back pressure space and the low pressure space.
JP 2000-291571 A

  However, as described above, in the configuration in which the discharge pressure or the like of the high-pressure refrigerant is used as the back pressure, when the difference between the refrigerant suction side pressure and the discharge pressure is small, the pressing force is insufficient, and the second The behavior of the member tends to be unstable. For this reason, it is conceivable to increase the diameter of the seal ring located on the back side of the second member, to secure the pressing force of the second member even at a low differential pressure, and to stabilize the behavior of the second member. .

  However, if the seal ring has a large diameter in this way, it is effective at a low differential pressure where the pressing force is insufficient, but in other cases, the second member is pressed against the first member more than necessary. The friction loss of the sliding surface between the first member and the second member is increased.

  Here, the behavior of the second member depends on the pressure difference between the refrigerant suction side pressure and the discharge pressure, and the relative rotational speed between the first member and the second member, and the pressure difference is large. In some cases and at high rotational speeds, the behavior is stable, but when the differential pressure is small and the rotational speed is low, the behavior becomes unstable. Therefore, as in the configuration of Patent Document 1 described above, when the pressure is adjusted so that the pressure in the back pressure space is always constant, even when the differential pressure is small, a constant back pressure is applied, so the behavior of the second member is Although stable, the relative rotational speed between the first member and the second member is not considered, so the rotational speed is high even if the differential pressure is small, that is, the behavior of the second member is not unstable. In addition, an unnecessarily high back pressure is applied, and there is a problem that friction loss increases.

  The present invention has been made in view of the above points, and in a rotary compressor in which the first member and the second member rotate relatively eccentrically in a press-contact state, the behavior of the second member is stabilized. However, the friction loss between the first member and the second member is reduced as much as possible to improve the operation efficiency.

  In order to achieve the above object, in the rotary compressor (1,101) according to the present invention, when the behavior of the second member (22,140) is unstable, the lubricating oil enters the back pressure space (S3, S3 ′). Paying attention to the point that many leaks, the oil reservoir (23c, 150b) is provided in the back pressure space (S3, S3 '), and the oil reservoir (23c, 150b) and the low pressure space (S1, S1') A communication passage is provided between the back pressure spaces (S3, S3 ′) in accordance with the amount of lubricating oil accumulated in the oil reservoir (23c, 150b).

  Specifically, in the first invention, the first member (21, 135) and the second member (22, 140) that are relatively eccentrically rotated while being pressed against each other are provided, and the second member (22, 140) is provided. A back pressure space (S3, S3 ′) is formed on the back side, and the back pressure space (S3, S3 ′) is against the thrust surface between the first member (21, 135) and the second member (22, 140). A rotary compressor (1,101) configured to supply lubricating oil from a higher pressure space (S2, S2 ') is targeted.

  The back pressure space (S3, S3 ′) is provided with an oil reservoir (23c, 150d) in which lubricating oil leaked from the thrust surface is provided, and the oil reservoir (23c, 150d) and Between the back pressure space (S3, S3 ′) and the lower pressure space (S1, S1 ′), the back pressure space depends on the amount of lubricating oil flowing into the oil reservoir (23c, 150d). It is assumed that a communication path (43, 180) for adjusting the pressure in (S3, S3 ′) is provided.

  With this configuration, when the behavior of the second member (22,140) becomes unstable, the lubricating oil flows from between the first member (21,135) and the second member (22,140) into the back pressure space (S3, S3 ′). The lubricating oil leaks and accumulates in the oil reservoir (23c, 150b) in the back pressure space (S3, S3 ′). Then, the back pressure space between the oil reservoir (23c, 150b) and the low pressure space (S1, S1 ') depends on the amount of lubricating oil accumulated in the oil reservoir (23c, 150b). By providing the communication path (43,180) capable of adjusting the pressure in (S3, S3 '), the behavior of the second member (22,140) becomes unstable as described above, and the back pressure space (S3, S3') When the lubricating oil leaks out, it is possible to adjust the pressure of the back pressure space (S3, S3 ') and press the second member (22,140) against the first member (21,135) side. . On the other hand, when the behavior of the second member (22,140) is stable, the amount of lubricating oil leaking into the back pressure space (S3, S3 ') is small. By configuring the communication path (43,180) so that the pressure in (S3, S3 ') does not increase, the second member (22,140) is pressed more than necessary against the first member (21,135), It is possible to prevent an increase in friction loss.

  Specifically, the communication passage (43,180) is at least one in the passage length direction of the communication passage (43,180) when a predetermined amount or more of lubricating oil has accumulated in the oil reservoir (23c, 150b). It is assumed that the portion is filled with lubricating oil (second invention). By doing so, the lubricating oil is not discharged from the communication passage (43,180) until the lubricating oil of a predetermined amount or more is accumulated in the oil reservoir (23c, 150b), and in the back pressure space (S3, S3 '). When only a predetermined amount of lubricating oil accumulates in the oil reservoir (23c, 150b), the lubricating oil in the oil reservoir (23c, 150b) causes the oil in the communication passage (43,180) At least a portion of is satisfied. That is, when the behavior of the second member (22,140) becomes unstable and more than a predetermined amount of lubricating oil accumulates in the oil reservoir (23c, 150b), the low pressure space (S1, S1 ′) is in gas communication. The communication path (43, 180) is blocked by the lubricating oil, and the gas is confined in the back pressure space (S3, S3 ′). Here, the lubricating oil leaking into the back pressure space (S3, S3 ′) is supplied from the high pressure space (S2, S2 ′) between the first member (21, 135) and the second member (22, 140). If the refrigerant leaks into the back pressure space (S3, S3 ′), the refrigerant dissolved in the lubricating oil foams and the pressure in the back pressure space (S3, S3 ′) increases. .

  As the pressure in the back pressure space (S3, S3 ′) increases in this way, the force (back pressure) that presses the second member (22, 140) against the first member (21, 135) increases, The behavior of the two members (22,140) can be stabilized.

  On the other hand, when a predetermined amount or more of lubricating oil does not accumulate in the oil reservoir (23c, 150b), that is, the behavior of the second member (22,140) is stable, and the second member (22,140) When the amount of lubricating oil leaked from the first member (21,135) is small, only the gas escapes from the communication passage (43,180) to the low pressure space (S1, S1 '), and the back pressure space (S3 , S3 ′) does not increase, so that it is possible to prevent an increase in friction loss between the first member (21, 135) and the second member (22, 140).

  Therefore, with the above-described configuration, when the behavior of the second member (22, 140) is unstable, the pressure in the back pressure space (S3, S3 ′) is increased, and the second member ( 22 and 140) can be stabilized, while when the behavior of the second member (22,140) is stable, the pressure in the back pressure space (S3, S3 ′) is prevented from increasing, It is possible to prevent an increase in friction loss between the member (21, 135) and the second member (22, 140).

  The communication passage (43) has a communication passage (43) in accordance with a differential pressure between the high pressure space (S2) and the back pressure space (S3) or the low pressure space (S1). It is assumed that fluid resistance changing means (44) for changing the fluid resistance is provided (third invention).

  As described above, the behavior of the second member (22) becomes unstable because the differential pressure between the pressure on the refrigerant suction side (low pressure space) and the pressure on the discharge side (high pressure space) is small. Since the relative rotational speed between the member (21) and the second member (22) is low, the pressure difference between the low pressure space (S1) and the high pressure space (S2) is small, that is, the pressure in the high pressure space (S2). Is not sufficiently high, and the behavior of the second member (22) may become unstable, the fluid resistance of the communication passage (43) is changed according to the differential pressure, and the communication passage By changing the pressure loss in (43), it is possible to increase the pressure in the back pressure space (S3) and stabilize the behavior of the second member (22). That is, by changing the fluid resistance of the communication passage (43) by the fluid resistance changing means (44), the pressure in the back pressure space (S3) can be easily and reliably changed.

  In particular, the fluid resistance changing means (44) reduces the fluid resistance of the communication passage (43) when the differential pressure is greater than or equal to a predetermined value, while the fluid resistance changing means (44) reduces the fluid resistance when the differential pressure is smaller than the predetermined value. It is preferable that the fluid resistance of the communication path (43) is increased (fourth invention). Here, the predetermined value means a differential pressure when the behavior of the second member (22) starts to stabilize. That is, if the differential pressure is greater than or equal to a predetermined value, the behavior of the second member (22) is stable, but if the differential pressure is smaller than the predetermined value, it may become unstable in relation to the rotational speed.

  With the above configuration, when the differential pressure between the low pressure space (S1) and the high pressure space (S2) is a predetermined value or more, the behavior of the second member (22) is stable. Since there is no need to increase the pressure in the back pressure space (S3) even when a large amount of lubricating oil is accumulated in the oil reservoir (23c), the fluid resistance of the communication passage (43) can be reduced to reduce the lubricating oil. Is quickly discharged from the communication passage (43) to the low pressure space (S1), so that the pressure in the back pressure space (S3) can be prevented from rising so much. On the other hand, when the differential pressure is smaller than a predetermined value, the behavior of the second member (22) is likely to be unstable. Therefore, the fluid resistance of the communication passage (43) is increased to increase the communication pressure. By increasing the pressure loss when the lubricating oil flows in the passage (43), the pressure in the back pressure space (S3) can be increased efficiently.

  Therefore, when the differential pressure is small and the amount of lubricating oil leaked is large, the behavior of the second member (22) can be stabilized by increasing the pressure in the back pressure space (S3) more reliably. On the other hand, when the differential pressure is large, it is possible to reliably prevent the pressure in the back pressure space (S3) from increasing and the friction loss between the first member (21) and the second member (22) from increasing. .

  Here, the fluid resistance changing means (44) is preferably a variable throttle valve configured to be able to switch the cross-sectional area of the communication passage (43) by the differential pressure (fifth invention). As described above, the cross-sectional area of the communication path (43) can be switched by the variable throttle valve, so that the communication path (43) can be switched according to the pressure difference between the high pressure space (S2) and the low pressure space (S1). The fluid resistance can be easily changed, and the pressure control in the back pressure space (S3) can be performed more reliably.

  In particular, the variable throttle valve (44) has one side of the valve chamber (44a) partitioned by the valve body (44b) so that the valve body (44b) can reciprocate in the valve chamber (44a). It is assumed that the high pressure space (S2) communicates and the other side of the valve chamber (44a) communicates with either the back pressure space (S3) or the low pressure space (S1) (sixth invention).

  By constructing the variable throttle valve (44) in this way, the valve body (44b) has a valve chamber (44) due to a differential pressure between the high pressure space (S2) and the low pressure space (S1) (or back pressure space (S3)). 44a) Since it moves in, the valve operation according to the differential pressure is possible with a simple configuration.

  The above configuration can be applied to the rotary compressor (1, 101) having the following configuration. That is, the first and second members (21, 135, 22, 140) may be scroll members in which a spiral wrap is provided on the end plate (seventh invention), and the first member (135) The cylinder (152, 138) has an annular cylinder chamber (160, 165), and the second member (140) is housed in the cylinder chamber (160, 165) in an eccentric state with respect to the cylinder (152, 138). Each of the compression chambers (160, 165) and the low pressure side (162, 167) is constituted by an annular piston that divides the chamber (160, 165) into an outer compression chamber (160) and an inner compression chamber (165). It may be a rotary compressor in which the blade (145) divided into the above is provided across the cylinder (152, 138) and the piston (140) (eighth invention).

  According to the first invention, the oil reservoir (23c, 150b) is provided in the back pressure space (S3, S3 ′) formed on the back surface of the second member (22, 140), and the oil reservoir (23c 150b) and the low pressure space (S1, S1 '), the pressure in the back pressure space (S3, S3') is adjusted according to the amount of lubricating oil flowing into the oil reservoir (23c, 150b) Since the communication passage (43,180) for carrying out the operation is provided, the back pressure space (22,140) corresponding to the behavior of the second member (22,140) affecting the amount of oil leaked into the back pressure space (S3, S3 ′) It becomes possible to change the pressure of S3, S3 '). Accordingly, while stabilizing the behavior of the second member (22,140), when the behavior of the second member (22,140) is stable, an excessive pressing force is applied to the second member (22,140). It is possible to prevent an increase in friction loss with the first member (21, 135). In addition, since it is not necessary to increase the diameter of the seal ring with the above-described configuration, it is possible to reduce the thrust loss when the behavior of the second member (22, 140) is stable.

  In particular, according to the second invention, when the behavior of the second member (22,140) is unstable and a predetermined amount or more of lubricating oil has accumulated in the oil reservoir (23c, 150b), Since at least part of the passageway (43,180) is filled with the lubricating oil and the back pressure space (S3, S3 ′) is in an airtight state, the pressure in the back pressure space (S3, S3 ′) is increased to The pressing force acting on the two members (22,140) is increased, and thereby the behavior of the second member (22,140) can be stabilized. On the other hand, when the lubricating oil of a predetermined amount or more does not accumulate in the oil reservoir (23c, 150b), that is, when the behavior of the second member (22,140) is stable, the communication path (43,180) Is not blocked by the lubricating oil, so the pressure in the back pressure space (S3, S3 ′) does not rise very much. Therefore, when the behavior of the second member (22,140) is stable, it is possible to prevent an excessive pressing force from acting on the second member (22,140), and the second member (22,140) and the first member It is possible to prevent an increase in friction loss with the members (21, 135).

  Further, according to the third aspect of the invention, the fluid in the communication path (43) is determined according to the differential pressure between the high pressure space (S2) and the lower pressure space (S1, S3) in the communication path (43). Since the fluid resistance changing means (44) for changing the resistance is provided, the communication path is in accordance with the pressure of the high pressure space (S2), which is one of the factors that cause the behavior of the second member (22) to become unstable. The flow of the lubricating oil in (43) can be controlled, whereby the pressure in the back pressure space (S3) can be controlled easily and reliably.

  In particular, according to the fourth invention, the fluid resistance changing means (44) reduces the fluid resistance of the communication passage (43) when the differential pressure is greater than or equal to a predetermined value, while the differential pressure is less than the predetermined value. If the pressure is too small, it is possible to increase the fluid resistance of the communication passage (43), so that the differential pressure is smaller than a predetermined value and the behavior of the second member (22) may become unstable. Only in this case, the fluid resistance of the communication passage (43) increases and the lubricating oil does not flow easily, so that the pressure in the back pressure space (S3) can be reliably increased.

  According to the fifth aspect of the invention, the fluid resistance changing means (44) is constituted by the variable throttle valve capable of changing the cross-sectional area of the communication passage (43) by the differential pressure, so the communication passage according to the differential pressure. The fluid resistance of (43) can be changed with certainty, whereby the pressure in the back pressure space (S3) can be adjusted more reliably.

  In particular, according to the sixth aspect of the invention, the variable throttle valve (44) has one side of the valve chamber (44a) partitioned by the valve body (44b) communicating with the high pressure space (S2), Since the other side of (44a) communicates with either the back pressure space (S3) or the low pressure space (S1), the variable throttle valve (44) must be operated with a simple configuration and with a differential pressure. Is possible.

  According to the seventh and eighth aspects of the present invention, the above-described configuration has a scroll compressor in which the first and second members (21, 135, 22, 140) are scroll members, and a cylinder in which the first member (21, 135) is an annular shape. A cylinder having a chamber, and the second member (22,140) is a piston that divides the cylinder chamber into two compression chambers, and each compression chamber is divided into a high pressure side and a low pressure side across the piston and the cylinder. By applying the present invention to a rotary compressor provided with blades that perform the above-described effects, the effects of the first to sixth inventions described above can be obtained in these rotary compressors.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature and is not intended to limit the present invention, its application, or its use.

(Embodiment 1)
A rotary compressor (1) according to Embodiment 1 of the present invention is formed between a stationary scroll (21) as a first member and a movable scroll (22) as a second member, which are relatively rotated. The scroll compressor is configured to compress the refrigerant in the compression chamber (C), and is provided, for example, in a refrigerant circuit that performs a vapor compression refrigeration cycle of the air conditioner.

  As shown in FIG. 1, the rotary compressor (1) includes a casing (10). The casing (10) houses a compression mechanism (20) for compressing the refrigerant and a drive mechanism (30) for driving the compression mechanism (20). The drive mechanism (30) is disposed below the compression mechanism (20) and is connected to the compression mechanism (20) via a drive shaft (32).

  The casing (10) is formed by closing both ends of a cylindrical member extending in the vertical direction, and the casing (10) constitutes a sealed dome type pressure vessel.

  The compression mechanism (20) includes a fixed scroll (21) and a movable scroll (22) meshing with the fixed scroll (21), and the movable scroll (22) is interposed between the fixed scroll (21). A frame (23) forming a space for placement is provided.

  The frame (23) is airtightly joined to the upper inner surface of the casing (10) over the entire circumference. Thus, the casing (10) is partitioned into a relatively low pressure space (S1, S3) above the frame (23) and a high pressure space (S2) below the frame (23). That is, the scroll compressor (1) of the present embodiment is a so-called high and low pressure dome type scroll compressor having a low pressure space (S1) and a high pressure space (S2). As will be described later, the relatively low pressure space (S1, S3) above the frame (23) is further divided into upper and lower parts by a fixed scroll (21) and a movable scroll (22). The lower pressure space (S1) has a lower pressure, and the lower pressure space (S3) has a higher pressure. Here, the low-pressure space (S1) corresponds to the low-pressure portion of the present invention, and the high-pressure space (S2) corresponds to the high-pressure portion of the present invention.

  The frame (23) includes a frame recess (24) and a bearing portion (25). The frame recess (24) includes a first recess (24a) provided in a substantially ring shape on the upper surface of the frame (23) and a second recess provided on the inner side of the first recess (24a). It is comprised by the recessed part (24b). On the other hand, the bearing part (25) is formed so that the lower surface side of the center part of the frame (23) provided with the second recessed part (24b) bulges downward. As shown in FIG. 2, a through hole (25a) is formed in the bearing portion (25), and the through hole is provided by a bearing (25b) provided on the inner peripheral surface of the through hole (25a). The drive shaft (32) inserted through (25a) is rotatably supported.

  The fixed scroll (21) includes a substantially disc-shaped end plate (21a) and a spiral fixed side wrap (21b) standing on the lower surface of the end plate (21a).

  On the other hand, the movable scroll (22) includes a substantially disc-shaped end plate (22a) and a spiral movable side wrap (22b) standing on the upper surface of the end plate (22a). A substantially cylindrical boss (22d) extending downward is formed on the lower surface of the end plate (22a). The movable wrap (22b) is configured to mesh with the wrap (21b) of the fixed scroll (21). An eccentric portion (32a) formed at the upper end of the drive shaft (32) is inserted into the boss (22d) via a slide bearing (22c), thereby drivingly connecting the drive shaft (32). Has been.

  The end plate (22a) of the movable scroll (22) covers the upper part of the second recessed portion (24b) of the frame (23), and its outer peripheral end is located in the first recessed portion (24a). The boss (22d) is located in the second recessed portion (24b). A ring-shaped groove between the first concave portion (24a) and the second concave portion (24b) of the frame (23) in a top view so as to surround the outer periphery of the second concave portion (24b). (23b) is formed, and a seal ring (41) is disposed in the groove (23b).

  An Oldham coupling (26) for preventing the rotation of the movable scroll (22) is disposed between the end plate (22a) of the movable scroll (22) and the bottom surface of the first recess (24a). .

  The Oldham coupling (26) consists of an annular ring (only a cross section is shown in FIGS. 1 and 2). Scroll keys (not shown) are provided at positions opposite to each other on the ring and on the upper side of the ring. On the other hand, the ring is shifted by 90 degrees in the circumferential direction with respect to the scroll key. On the lower side, a pair of frame keys (not shown) protrudes. That is, the scroll key and the frame key are provided such that respective center lines extending in the ring radial direction form a right angle when viewed from above.

  A first guide groove (not shown) extending in the radial direction corresponding to the scroll key of the Oldham coupling (26) is formed on the lower surface of the end plate (22a) of the movable scroll (22). On the other hand, a second guide groove (not shown) extending in the radial direction corresponding to the frame key of the Oldham coupling (26) is also formed on the bottom surface of the first recess (24a) of the frame (23). . The first guide groove and the second guide groove are configured such that the scroll key fits in the first guide groove and the frame key fits in the second guide groove (not shown) and slides. ing. That is, both the keys and the guide grooves can prevent the movable scroll (22) from rotating, and the movable scroll (22) revolves relative to the frame (23). It is configured as follows.

  As shown in FIG. 1, the casing (10) has a suction pipe (14) for guiding the refrigerant in the refrigerant circuit to the compression mechanism (20), and discharges the refrigerant in the casing (10) to the outside of the casing (10). And a discharge pipe (15). The suction pipe (14) communicates with the low pressure space (S1), and the discharge pipe (15) communicates with the high pressure space (S2). In this way, by connecting the suction pipe (14) to the low pressure space (S1), the refrigerant sucked from the suction pipe (14) once enters the low pressure space (S1), and then compressed. It will flow to the mechanism (20).

  In the compression mechanism (20), the fixed scroll (21) has a suction port (Pi) and a discharge port (Po), while the fixed scroll (21) has a fixed wrap (21b) and a movable scroll (22). ), A compression chamber (C) is defined in the gap between the contact portions with the movable side wrap (22b). Here, although not particularly illustrated, the suction port (Pi) communicates with the low pressure space (S1) from the outer peripheral end of the compression chamber (C), while the discharge port (Po) is connected to the compression chamber (C). Is communicated with the high-pressure space (S2) through the discharge recess (28a) and the communication passage (not shown).

  That is, the compression mechanism (20) causes the refrigerant in the low pressure space (S1) to be sucked into the compression chamber (C) through the suction port (Pi) by the revolving motion of the movable scroll (22), and the compression chamber (C) After being compressed inside, it is discharged from the discharge port (Po) and flows into the high-pressure space (S2) through the discharge recess (28a) and the communication path (not shown). Thus, in the compression chamber (C), since the sucked refrigerant is compressed, the fixed scroll (21) and the movable scroll (22) constituting the compression chamber (C) have the compression chamber (C ) Acts, and forces (separation forces) that separate from each other are applied.

  The drive mechanism (30) is constituted by a motor (31) disposed in the high-pressure space (S2). The motor (31) includes a stator (33) and a rotor (34), and is fixed in a state where the drive shaft (32) is inserted into the substantially cylindrical rotor (34).

  A storage part (59) for storing lubricating oil is formed at the bottom of the casing (10). The drive shaft (32) is disposed with its lower end immersed in the storage (59). In the casing (10), the reservoir portion (59) located below the frame (23) and having a high pressure is filled with an oil supply hole penetrating the drive shaft (32) in the axial direction by the pressure. The lubricating oil rises in the through-hole (32b), and is supplied to each bearing of the drive shaft (32) from a branch in the drive shaft (32). On the other hand, the lubricating oil that has reached the tip of the drive shaft (32) passes through a lubricant oil passage and a throttle (not shown) inside the movable scroll (22) rotatably connected to the tip of the drive shaft (32). Via the sliding surfaces of both scrolls (21, 22) and the guide grooves provided corresponding to the keys of the Oldham coupling (26).

  The second recessed portion (24b) of the frame (23) is in a high temperature state because it communicates with the high pressure space (S2), and the movable scroll (22) covering the second recessed portion (24b) To the fixed scroll (21) side. Here, since the high pressure portion on the back surface of the movable scroll (22) is partitioned by the seal ring (41) disposed on the back surface of the movable scroll (22), the size of the seal ring (41) ( The size of the pressing force is determined by the radial dimension).

  Further, in the sliding surfaces of the scrolls (21, 22) to which the lubricating oil is supplied from the storage part (59), the surface on the fixed scroll (21) side has a substantially ring-shaped oil supply groove ( 21d) is provided. In the oil supply groove (21d), high-pressure lubricating oil from the reservoir (59) is supplied by a supply passage (not shown), and the movable scroll (22) is supported by the hydraulic pressure of the supplied lubricating oil. It is configured.

  That is, as described above, the movable scroll (22) is subjected to a separating force to move away from the fixed scroll (21) by the internal pressure of the compression chamber (C), while the movable scroll (22) Since the inside of the second recessed portion (24b) of the frame (23) located at a high pressure is pressed against the fixed scroll (21), if the pressing force is too large, the movable scroll (22) Since the friction loss on the sliding surface with the fixed scroll (21) increases, the oil supply groove (21d) is provided on the sliding surface of the fixed scroll (21), and high pressure lubricating oil is supplied to press the By reducing the force, the balance between the separation force and the pressing force is achieved.

  In addition to the high-pressure lubricating oil in the second recessed portion (24b) of the frame (23), the pressing force is a back pressure formed between the movable scroll (22) and the frame (23). It is also caused by the pressure in the space (S3).

  Thus, the separation force and the pressing force acting on the movable scroll (22) balance each other if the high-pressure space (S2) in the casing (10) is in a sufficiently high pressure state. The friction loss on the sliding surfaces of the fixed scroll (21) and the movable scroll (22) can be made appropriate while ensuring the airtightness of the compression chamber (C). However, when the inside of the high pressure space (S2) is not sufficiently high in pressure, the pressing force of the movable scroll (22) is insufficient, and the movable scroll (22) is separated from the fixed scroll (21). The movable scroll (22) may exhibit unstable behavior such as partly separating.

  Specifically, as described above, the movable scroll (22) exhibits an unstable behavior when the pressing force is insufficient because the differential pressure between the high pressure space (S2) and the low pressure space (S1) is small. Since the differential pressure between the high-pressure space (S2) and the low-pressure space (S1) is slightly small and the rotational speed of the movable scroll (22) is low, the discharge chamber (Po) and the compression chamber (C ) When a large amount of high-pressure refrigerant gas leaks into the interior, the internal pressure of the compression chamber (C) increases, thereby increasing the separation force, and the pressing force against the movable scroll (22) is relatively insufficient. is there. At this time, since the movable scroll (22) is inclined (overturned) with respect to the fixed scroll (21), the high-pressure lubricant supplied to the oil supply groove (21d) on the sliding surface of the fixed scroll (21) It will leak into the pressure space (S3). Even when the pressure in the high pressure space (S2) is sufficiently high, or even if the pressure in the high pressure space (S2) is slightly low, the rotational speed of the movable scroll (22) is sufficiently high, so When there is little leakage of the high pressure gas, the behavior of the movable scroll (22) is stable, and a large amount of lubricating oil does not leak from the oil supply groove (21d) of the fixed scroll (21).

  In order to stabilize the behavior of the movable scroll (22), the size of the seal ring (41) is increased so that a sufficient pressing force can be obtained even when the pressure in the high pressure space (S2) is small. Thus, it is conceivable to increase the back pressure acting on the back surface of the movable scroll (22). However, in such a configuration, when the pressure in the high-pressure space (S2) increases, the pressing force of the movable scroll (22) becomes too large, and the friction loss between the scrolls (21, 22) increases. As a result, the driving efficiency is reduced.

  Therefore, in the present invention, as described above, when the behavior of the movable scroll (22) is unstable, the lubricating oil leaks from between the sliding surfaces of the scrolls (21, 22), and the back pressure space Paying attention to the points accumulated in (S3), the following configuration is adopted to stabilize the behavior of the movable scroll (22) without increasing the friction loss.

  That is, in the present invention, the oil reservoir (23c) is provided on the upper surface of the frame (23) (the side facing the back pressure space), and the oil reservoir (23c) and the low pressure space (S1) In the middle, a drain oil passage (43) is provided so that the pressure in the back pressure space (S3) can be adjusted in accordance with the amount of lubricating oil accumulated in the oil reservoir (23c).

  Specifically, an oil reservoir (23c) is formed as a part of the back pressure space (S3) on the upper surface of the frame (23), and the oil reservoir (23c) has a low pressure The lower end portion of the oil drain pipe (42) communicating with the space (S1) is positioned. This drain pipe (42) is connected to the back pressure space (S3) side of the communication hole (21c) formed in the fixed scroll (21) so that the low pressure space (S1) and the back pressure space (S3) communicate with each other. It is provided so as to extend downward from. That is, the oil discharge pipe (42) and the communication hole (21c) constitute the oil discharge path (43).

  As described above, since the lower end of the oil drain pipe (42) is positioned in the oil reservoir (23c), lubricating oil accumulates in the oil reservoir (23c) and the oil drain pipe (42 ), The lubricating oil in the oil reservoir (23c) is discharged to the low pressure space (S1) through the communication hole (21c). can do.

  At this time, the exhaust oil passage (43) communicating the back pressure space (S3) and the low pressure space (S1) is in a state where at least part of the oil passage length direction is filled with the lubricating oil. Thus, the back pressure space (S3) is airtight. Then, the high-pressure refrigerant dissolved in the lubricating oil leaking from between the sliding surfaces of the scrolls (21, 22) foams, and the back pressure space (S3) becomes high pressure. Thus, when the pressure in the back pressure space (S3) located on the back surface of the movable scroll (22) rises, the movable scroll (22) can be sufficiently pressed against the fixed scroll (21) side, The behavior of the movable scroll (22) can be stabilized.

  Thus, after stabilizing the behavior of the movable scroll (22), the amount of lubricating oil leaking from between the sliding surfaces of the movable scroll (22) and the fixed scroll (21) is reduced. The lubricating oil in the oil reservoir (23c) is discharged from the oil drain pipe (42) to the low-pressure space (S1) by the pressure in the back pressure space (S3), and the oil in the oil reservoir (23c) The surface is lowered. When the oil level of the oil reservoir (23c) is positioned below the lower end of the oil drain pipe (42), the lubricating oil is not discharged from the oil drain pipe (42), and the back pressure space Only the gas in (S3) will flow to the low pressure space (S1) side, the pressure in the back pressure space (S3) will drop, and an extra pressing force will act on the back of the movable scroll (22) Can be prevented.

  In this embodiment, an example is described in which the behavior of the movable scroll (22) becomes stable after the behavior becomes unstable. However, the behavior of the movable scroll (22) is stable from the beginning. In addition, since the lubricating oil that can be discharged through the oil drain pipe (42) does not accumulate in the oil reservoir (23c), the pressure in the back pressure space (S3) does not increase. is there.

  The drain oil passage (43) has a variable throttle valve as fluid resistance changing means that can change the fluid resistance of the oil passage (43) by changing the cross-sectional area of the oil passage (43). (44) is provided. That is, as shown in FIGS. 3 to 5 in an enlarged manner, the variable throttle valve (44) communicates with a part of the communication hole (21c) of the discharge oil passage (43) in the fixed scroll (21). ) Is formed, and a substantially columnar valve body (44b) is elastically supported by the spring (44c) in the valve chamber (44a).

  The valve chamber (44a) is a space formed longer than the valve body (44b) so that the substantially columnar valve body (44b) can reciprocate inside, and is orthogonal to the longitudinal direction of the space. The communication holes (21c) that constitute a part of the drain oil passage (43) are opened at positions facing each other in the direction in which they are directed. The valve chamber (44a) has a communication hole (45) with the high pressure space (S2) and a communication hole (46) with the low pressure space (S1) at positions facing each other in the longitudinal direction. . That is, the communication hole (45) with the high pressure space (S2) communicates with the space (48) on one side of the valve chamber (44a) defined by the valve body (44b), while the low pressure space The communication hole (46) with (S1) communicates with the space (49) on the other side of the valve chamber (44a) defined by the valve body (44b). 3 to 5 schematically show the configuration of the variable throttle valve (44) for simplification of description, and the connection position of the communication hole (45, 46) to the valve chamber (44a). Etc. are different from the actual configuration (FIGS. 1 and 2). Further, the communication hole (46) only needs to communicate with a lower pressure space than the high pressure space (S3), so that it communicates with the back pressure space (S3) instead of the low pressure space (S1) as described above. It may be.

  In this way, by introducing a high pressure on one side of the valve body (44b) and a low pressure on the other side in the valve chamber (44a), the difference between the high pressure space (S2) and the low pressure space (S1) is obtained. The valve body (44b) can be operated by pressure. The spring (44c) is disposed between the valve body (44b) and the inner surface of the valve chamber (44a) on the side where the low pressure is introduced to the valve body (44b) (left side in the figure). The valve body (44b) is urged toward the high pressure side (right side in the figure). That is, the variable throttle valve (44) is configured so that the high-pressure side force and the low-pressure side force acting on the valve body (44b) are balanced by the spring (44c).

  The valve body (44b) is made of a substantially cylindrical member, and has two through holes (44d, 44e) of different sizes formed side by side in the longitudinal direction. Further, seals (47) made of, for example, rubber or the like are provided at both longitudinal ends of the valve body (44b). As described above, the valve body (44b) is placed in the valve chamber (44a). The high-pressure chamber (48) and the low-pressure chamber (49) partitioned by each other are configured not to communicate with each other. Further, the valve body (44b) is positioned in the valve chamber (44a) due to the pressure relationship between the high pressure chamber (48) and the low pressure chamber (49) in the valve chamber (44a), and two through holes ( 44d, 44e) is configured to communicate with the communication hole (21c) of the discharge oil passage (43) that opens to the valve chamber (44a). That is, the valve body (44b) is configured to switch the through holes (44d, 44e) communicating with the communication hole (21c) by the differential pressure.

  Next, the operation of the variable throttle valve (44) will be described with reference to FIGS.

  When the pressure in the high pressure space (S2) is small, the valve body (44b) is on the high pressure side (right side in the figure) as shown in FIG. 3 due to the pressure in the low pressure space (S1) and the elastic restoring force of the spring (44c). Move to. Then, among the through holes (44d, 44e) provided in the valve body (44b), the small diameter through hole (44d) communicates with the communication hole (21c) constituting a part of the drain oil passage (43). To do. In this case, since the diameter of the through hole (44d) is smaller than the diameter of the communication hole (21c), the opening of the valve is reduced as shown in FIG. ) Is partially reduced, the fluid resistance of the entire drain oil passage (43) is increased, and the lubricating oil does not easily flow inside.

  When the pressure in the high-pressure space (S2) becomes larger than that in the above case, the relationship between the pressure in the low-pressure space (S1) and the resultant elastic restoring force of the spring (44c) is shown in FIGS. As shown in FIG. 5, the position of the valve body (44b) is determined. For example, when the valve body (44b) is in the position shown in FIG. 4, the communication hole (21c) is positioned between the two through holes (44d, 44e). A part of both the through holes (44d, 44e) communicates with (21c). Even in this case, as shown in FIG. 4C, the opening degree is small, and the fluid resistance is increased by the valve body (44b), so that the lubricating oil hardly flows inside. On the other hand, when the valve body (44b) is in the position shown in FIG. 5, the large-diameter through hole (44e) communicates with the communication hole (21c), and the valve body (44b) As shown in FIG. 5C, the opening degree of the valve is increased, the fluid resistance is relatively decreased, and the lubricating oil easily flows.

  Here, when the valve body (44b) is in the position shown in FIG. 5, the pressure in the high-pressure space (S2) is sufficiently large and the differential pressure is equal to or greater than a predetermined value, that is, This is a case where a sufficient pressing force is acting on the movable scroll (22).

  Thus, by providing the variable throttle valve (44), it is possible to change the fluid resistance of the discharge oil passage (43) for discharging the lubricating oil from the oil reservoir (23c) to the low pressure space (S1). In addition, pressure loss occurs due to the passage of the lubricating oil through the variable throttle valve (44), so that the pressure in the back pressure space (S3) can be adjusted.

  Moreover, the variable throttle valve (44) operates according to the pressure relationship between the high pressure space (S2) and the low pressure space (S1), and when the pressure in the high pressure space (S2) is small, the drain oil passage (43) To increase the pressure in the back pressure space (S3) to secure the pressing force of the movable scroll (22), while the pressure in the high pressure space (S2) is high, By reducing the fluid resistance of the oil passage (43) so that the lubricating oil flows smoothly in the discharge oil passage, the back pressure can be increased even when the behavior of the movable scroll (22) is stable. It can be prevented that the pressure in the space (S3) rises unnecessarily and the friction loss between the scrolls (21, 22) increases.

-Driving action-
Next, the operation of the rotary compressor (1) having the above configuration will be described.

  First, when the motor (31) is driven, the drive shaft (32) rotates and the movable scroll (22) performs a revolving motion with respect to the fixed scroll (21). At that time, in the Oldham coupling (26), the scroll key slides in the first guide groove of the movable scroll (22), while the frame key slides in the second guide groove of the frame (23). The rotation of the scroll (22) is prevented. Accordingly, the movable scroll (22) performs a revolving motion with the predetermined eccentric amount of the eccentric portion (32a) of the drive shaft (32) as the revolution radius.

  As the movable scroll (22) revolves, the volume of the compression chamber (C) repeatedly increases and decreases periodically. When the volume of the compression chamber (C) increases, the refrigerant in the refrigerant circuit is drawn into the low-pressure space (S1) from the suction pipe (14). The refrigerant sucked into the low pressure space (S1) is sucked into the compression chamber (C) from the suction port (Pi) of the fixed scroll (21). Next, the refrigerant sucked into the compression chamber (C) is compressed and discharged from the discharge port (Po) when the volume of the compression chamber (C) decreases. Thereafter, the compressed refrigerant flows into the high-pressure space (S2) through the communication path and returns from the discharge pipe (15) to the refrigerant circuit. The rotary compressor (1) according to the present embodiment is a scroll compressor as described above, and the compression operation of the refrigerant in the compression mechanism (20) is the same as that conventionally known. Is omitted.

  The second recessed portion (24b) of the frame (23) is in a high pressure state because it communicates with the high pressure space (S2), and the movable scroll (2) facing the second recessed portion (24b) Then, it is pressed from the back side to the fixed scroll (21) side. This pressing force is a force opposite to the separating force due to the internal pressure of the compression chamber (C).

  On the other hand, the lubricating oil in the storage part (59) located in the lower part of the casing (10) has a through hole in the drive shaft (32) due to the pressure of the storage part (59) in the high-pressure space (S2). The inside of (32b) is pushed upward and supplied to the respective slide bearings (22c, 25a) of the drive shaft (32) from the branch inside the drive shaft (32). Further, the lubricating oil that has reached the upper end of the drive shaft (32) passes through a lubricating oil passage and a throttle (not shown) of the movable scroll (22) that is rotatably connected to the upper end of the drive shaft (32). The oil is supplied to an oil supply groove (21d) provided between the sliding surfaces of both scrolls (21, 22). The lubricating oil supplied to the oil supply groove (21d) lubricates the sliding surfaces of the scrolls (21, 22), and the lubricating oil leaking out of the sliding surfaces corresponds to each key of the Oldham coupling (26). Is also supplied to a guide groove or the like provided corresponding to the above.

  Since the lubricating oil in the oil supply groove (21d) is in a high pressure state, the pressing force of the movable scroll (22) can be relaxed to prevent an increase in friction loss between the scrolls (21, 22).

  Here, when the pressure in the high-pressure space (S2) is low and the rotational speed of the movable scroll (22) is low, the inside of the second recessed portion (24b) of the frame (23) is sufficiently high. Furthermore, since the amount of refrigerant gas leaked into the compression chamber (C) further increases, the separation force increases, and the behavior of the movable scroll (22) becomes unstable.

  Then, the lubricating oil leaks into the back pressure space (S3) from between the sliding surfaces of the movable scroll (22) and the fixed scroll (21). Since the oil reservoir (23c) is formed in the back pressure space (S3), the lubricating oil leaking from between the sliding surfaces of the scrolls (21, 22) (23c). Then, a predetermined amount or more of lubricating oil is accumulated in the oil reservoir (23c), and the oil level is a part of a drain oil passage (43) communicating with the low pressure space (S1). ), The lubricating oil in the oil reservoir (23c) passes through the oil drain pipe (42) and is discharged into the low pressure space (S1).

  At this time, since the pressure in the high-pressure space (S2) is low, the variable throttle valve (44) provided in the discharge oil passage (43) has a valve body (44b) in the high-pressure chamber in the valve chamber (44a). The small-diameter through hole (44d) formed in the valve body (44b) is communicated with the communication hole (21c) constituting the drain oil passage (43). As a result, the oil passage cross-sectional area of the drain oil passage (43) is reduced at the variable throttle valve (44), the fluid resistance increases, and a differential pressure is generated before and after the valve (44).

  By doing so, the pressure in the back pressure space (S3) can be increased, the pressing force of the movable scroll (22) can be secured, and the behavior of the movable scroll (22) can be stabilized.

  As described above, after the behavior of the movable scroll (22) is stabilized, the amount of lubricating oil leaking from between the sliding surfaces of the fixed scroll (21) and the movable scroll (22) decreases. When the oil level of the lubricating oil in the oil reservoir (23c) decreases and reaches the lower end of the oil drain pipe (42), the amount of lubricating oil passing through the variable throttle valve (44) decreases. For this reason, the pressure loss generated before and after the variable throttle valve (44) is reduced, and the pressure in the back pressure chamber (S3) is reduced, so that the pressing force of the movable scroll (22) is reduced.

  Thus, when the behavior of the movable scroll (22) becomes unstable, the pressure of the back pressure chamber (S3) increases, and when the behavior of the movable scroll (22) stabilizes, the back pressure chamber (S3) The pressure of the back pressure chamber (S3) is automatically adjusted to the minimum pressure that stabilizes the behavior of the movable scroll (22), and the pressing force of the movable scroll (22) is reduced. Can be prevented from increasing unnecessarily.

  On the other hand, when the pressure in the high pressure space (S2) is high, the variable throttle valve (44) moves to the low pressure chamber side in the valve chamber (44a). The large-diameter through hole (44e) formed in 44b) is communicated with the communication hole (21c). Then, the oil passage cross-sectional area of the drain oil passage (43) is not reduced and the fluid resistance does not increase, so that the lubricating oil flows smoothly in the drain oil passage (43) and the pressure in the back pressure space (S3) Hardly rises. That is, when the pressure in the high pressure space (S2) is high, the behavior of the movable scroll (22) is also stable, so that the pressure in the back pressure space (S3) is increased as described above. The lubricating oil accumulated in the oil reservoir (23c) can be discharged to the low pressure space (S1).

  As described above, the lubricating oil discharged to the low-pressure space (S1) is sucked together with the refrigerant from the suction port (Pi) of the fixed scroll (21) and compressed in the compression mechanism (20). The discharge port (Po) returns to the reservoir (59) in the high-pressure space (S2).

-Effect of Embodiment 1-
As described above, according to this embodiment, the oil reservoir (23c) is provided in the back pressure space (S3) located on the back side of the movable scroll (22), and the oil reservoir (23c) is provided with the oil reservoir (23c). By positioning the lower end of the drain oil pipe (42) that forms part of the drain oil passage (43) communicating with the low pressure space (S1), the movable scroll (22) becomes more unstable as the behavior of the movable scroll (22) becomes unstable. The amount of lubricating oil that leaks into the back pressure space (S3) from between the sliding surfaces of the scroll (22) and the fixed scroll (21) increases, and therefore accumulates in the oil reservoir (23c) and discharges the exhaust. The amount of oil discharged from the oil passage (43) to the low pressure space (S1) increases. At this time, as the lubricating oil passes through the variable throttle valve (44) provided in the drain oil passage (43), pressure loss occurs before and after the variable throttle valve (44), and the larger the amount of discharged oil, That is, as the behavior of the movable scroll (22) becomes unstable, the pressure in the back pressure space (S3) can be increased.

  On the other hand, when the behavior of the movable scroll (22) is stable, the amount of lubricating oil leaking from between the sliding surfaces of the movable scroll (22) and the fixed scroll (21) is small. The pressure loss due to the variable throttle valve (44) in (43) is reduced, and the pressure in the back pressure space (S3) does not become higher than necessary. That is, when the movable scroll (22) is stable, the pressing force of the movable scroll (22) increases, and the friction loss of the sliding surface between the scrolls (22, 23) increases. Can be prevented.

  Thus, in the above-described configuration, the pressure of the back pressure space (S3) is adjusted according to the behavior of the movable scroll (22), not the pressure of the back pressure space (S3) or the high pressure space (S2). Since the behavior of the movable scroll (22) can be stabilized, for example, even when the pressure in the high-pressure space (S2) is slightly low, the rotational speed of the movable scroll (22) is sufficiently high. Thus, when the movable scroll (22) is stable, it is possible to prevent the pressing force of the movable scroll (22) from being increased unnecessarily by increasing the pressure in the back pressure space (S3).

  Therefore, while stabilizing the behavior of the movable scroll (22), it is possible to prevent the friction efficiency between the movable scroll (22) and the fixed scroll (21) from becoming large and deteriorating the operation efficiency. That is, the behavior of the movable scroll (22) can be stabilized without increasing the diameter of the seal ring.

  The exhaust oil passage (43) is provided with a variable throttle valve (44) capable of changing the cross-sectional area of the oil passage (43) by the differential pressure between the low pressure space (S1) and the high pressure space (S2). When the differential pressure is small, that is, when the pressure in the high pressure space (S2) is small, the fluid resistance of the drain oil passage (43) is increased, while when the pressure in the high pressure space (S2) is large By reducing the fluid resistance of the drain oil passage (43), the pressure in the back pressure space (S2) can be increased only when the behavior of the movable scroll (22) may become unstable. it can.

  That is, when the pressure in the high pressure space (S2) is small, the behavior of the movable scroll (22) may become unstable. Therefore, by increasing the fluid resistance of the drain oil passage (43), The pressure in the back pressure space (S3) can be reliably increased.

  On the other hand, when the pressure in the high pressure space (S2) is large, the behavior of the movable scroll (22) is stable, so even if the amount of oil accumulated in the oil reservoir (23c) is large, By reducing the fluid resistance of the discharge oil passage (43) and smoothly discharging the lubricating oil to the low pressure space (S1), it is possible to prevent the pressure from increasing in the back pressure space (S3).

  Moreover, since the variable throttle valve (44) is configured to operate by the differential pressure between the low pressure space (S1) and the high pressure space (S2), the discharge oil passage ( It is possible to reliably change the fluid resistance of the drain oil passage (43) by switching the cross-sectional area of 43) with certainty. Moreover, the variable throttle valve (44) has a space (48) on one side of the valve body (44b) in the valve chamber (44a) as a high pressure space (S2) and a space (49) on the other side as a low pressure space (S1). ) With each other, it operates with a simple structure and reliably with the above differential pressure.

-Modification of Embodiment 1-
In the first embodiment, for example, as shown in FIG. 3, as the variable throttle valve (44), the valve body (44b) is provided with two through holes (44d, 44e) having different diameters, and these through holes (44d, 44e), in which at least one of the fluid resistances of the exhaust oil passage (43) is changed by communicating with the communication hole (21c) of the exhaust oil passage (43), the present invention is not limited to this. 6-8, the valve body (44b ') is provided with an elliptical through hole (44d'), and the area through which the through hole (44d ') communicates with the communication hole (21c) is gradually increased. It may be changed.

  Specifically, as shown in FIG. 6, an elliptical through hole (44d ′) is formed in the valve body (44b ′) of the variable throttle valve (44 ′), and the through hole (44d ′) When viewed from the axial direction, the area where the through hole (44d ') and the communication hole (21c) of the discharge passage (43) overlap, that is, the area where the two holes communicate, is the position of the valve body (44b'). It was configured to change according to. The configuration other than the through hole (44d ′) is the same as that of the variable throttle valve (44) of the first embodiment, and the valve body (44b ′) includes a high pressure space (S2) and a low pressure space (S1). It is comprised so that it may operate | move with the differential pressure | voltage.

  That is, when the pressure in the high pressure space (S2) is low, as shown in FIG. 6, the valve body (44b ′) moves to the high pressure side and penetrates through the valve body (44b ′). The hole (44d ′) hardly overlaps with the communication hole (21c), and the opening degree becomes small as shown in FIG. Therefore, as in the first embodiment, when the pressure in the high pressure space (S2) is low, the variable throttle valve (44 ′) operates to reduce the oil passage cross-sectional area of the discharge oil passage (43). Thus, the fluid resistance is increased, and the lubricating oil is less likely to flow through the drain oil passage (43).

  When the pressure in the high pressure space (S2) gradually increases, the valve element (44b ′) is positioned on the low pressure side as shown in FIGS. 7 and 8 according to the pressure difference with the low pressure space (S1). Will do. Specifically, when the valve body (44b ′) is in the position of FIG. 7, the through hole (44d ′) of the valve body (44b ′) communicates with the communication hole (21c) of the drain oil passage (43). The area becomes larger than that in the case of FIG. 6, and the opening degree of the valve also becomes larger as shown in FIG.

  When the valve body (44b ′) is positioned on the low pressure side as shown in FIG. 8, the entire cross-section of the through hole (44d ′) of the valve body (44b ′) is formed in the communication hole (21c). On the other hand, as shown in FIG. 8C, the opening degree of the valve becomes the largest. Therefore, when the pressure in the high-pressure space (S2) increases, the oil passage cross-sectional area of the drain oil passage (43) is not reduced so much by the variable throttle valve (44 '), and the inside of the drain oil passage (43) is reduced. Lubricant flows smoothly.

  By using the variable throttle valve (44 ′) having the above-described configuration to control the fluid resistance of the drain oil passage (43), the valve is opened as shown in FIGS. The degree can be reduced to almost zero, and the opening degree of the valve can be gradually changed. That is, since the fluid resistance can be changed in a wide range by the variable throttle valve (44 ′), the pressure loss in the drain oil passage (43) can be controlled more precisely. Therefore, finer pressure control in the back pressure space (S3) becomes possible.

(Embodiment 2)
Similarly to the first embodiment, the rotary compressor (101) according to the present embodiment is provided in the refrigerant circuit of the refrigerator, for example, and used to compress the refrigerant. The rotary compressor according to the first embodiment is also used. Since the configuration differs greatly from the compressor (1), the configuration and operation will be described in detail below.

  As shown in FIG. 9, the rotary compressor (101) according to the present embodiment is configured as a so-called hermetic type. The rotary compressor (101) includes a casing (110) formed in a vertically long sealed container shape. The casing (110) includes a cylindrical portion (112) formed in a vertically long cylindrical shape, and a pair of end plates formed in a bowl shape and provided outwardly projecting at both ends of the cylindrical portion (112). Part (113). One end plate portion (113) that closes the upper end side of the cylindrical portion (112) is provided with a discharge pipe (114) that penetrates the end plate portion (113) in the thickness direction. 112) is provided with a suction pipe (115) passing through the cylindrical portion (112) in the thickness direction.

  Here, in this embodiment, as shown in FIG. 9, the discharge pipe (114) communicates with the inside of the casing (110), while the suction pipe (115) is in the casing (110). It is connected to the compression mechanism (130). That is, in the rotary compressor (101), the refrigerant compressed by the compression mechanism (130) is discharged into the internal space of the casing (110), and then passes through the discharge pipe (114) to the casing (110). This is a so-called high-pressure dome type compressor that is configured to be discharged to the outside and in which the inside of the casing (110) is in a high-pressure state. That is, in this embodiment, the space in the casing (110) is a high-pressure space (S2 ′).

  Inside the casing (110), an electric motor (120) and a compression mechanism (130) are arranged in order from top to bottom. In addition, a drive shaft (125) is disposed inside the casing (110) so as to extend in the cylindrical axis direction in the cylindrical portion (112) of the casing (110). The drive shaft (125) The compression mechanism (130) and the electric motor (120) are connected via the. In addition, the bottom part in the casing (110) in the shape of a sealed container is a storage part (159) in which lubricating oil supplied to each sliding part of the compression mechanism (130) is stored.

  The drive shaft (125) has a main shaft portion (126) and an eccentric portion (127). The eccentric portion (127) is formed in a columnar shape having a larger diameter than the main shaft portion (126) at a position near the lower end of the drive shaft (125). The eccentric portion (127) is provided such that the shaft center is eccentric with respect to the shaft center of the main shaft portion (126). Furthermore, the eccentric part (127) is fixed to the piston (140) so as to be integrally rotatable in a state of passing through a piston (140) of a compression mechanism (130) described later.

  In addition, a through hole (125a) as an oil supply passage extending upward from the lower end of the drive shaft (125) is formed in the drive shaft (125). As a result, the lubricating oil in the reservoir (159) located at the bottom in the casing (110) rises in the through hole (125a) due to the high pressure in the casing (110), and the compression mechanism (130) To each sliding part.

  The electric motor (120) includes a stator (121) and a rotor (122). The stator (121) is fixed to the inner surface of the cylindrical portion (112) of the casing (110). The main shaft portion (126) of the drive shaft (125) passes through the rotor (122), and is arranged inside the cylindrical stator (121) in this state.

  The compression mechanism (130) includes a first housing (135), a second housing (150), and a piston (140). The first housing (135) and the second housing (150) are arranged so as to overlap in the vertical direction, and in a space surrounded by the first housing (135) and the second housing (150). The piston (140) is accommodated.

  The piston (140) is slidably fitted to the eccentric part (127) of the drive shaft (125), and the bearing part (143) on the outer peripheral side of the bearing part (143). An annular piston main body (142) positioned concentrically with respect to the bearing (143) and the annular piston main body (142) on the lower end side in the figure (one axial end side of the compression mechanism (130)). The annular piston main body (142) is formed in a substantially C-shaped shape in which a part of the annular ring is divided.

  The first housing (135) includes a flat plate portion (136), a peripheral portion (138), and a bearing portion (137), and is fixed to the inner surface of the casing (110) by the peripheral portion (138). On the other hand, the drive shaft (125) is rotatably supported by the bearing portion (137).

  Specifically, the flat plate portion (136) is formed in a thick disc shape, and the peripheral portion (138) located on the outer peripheral side of the flat plate portion (136) is welded or the like to the casing. It is fixed to the inner surface of the cylindrical portion (112) of (110). In addition, a bearing portion (137) that bulges upward is formed in the central portion of the flat plate portion (136), and the bearing portion (137) is arranged in the vertical direction on the bearing portion (137). A sliding bearing (137a) is provided for rotatably supporting the main shaft portion (126) of the drive shaft (125) in a state of passing through the shaft.

  The peripheral edge portion (138) is formed in a substantially cylindrical shape that bulges downward from the lower surface of the flat plate portion (136), and the suction port (139) penetrates the peripheral edge portion (138) in the radial direction. Is formed. The suction port (139) has one end opened to a space formed by the first and second housings (135, 150), and the other end is connected to the suction pipe (115). Thus, a part of the suction passage for sucking the refrigerant into the space is configured.

  Further, a substantially cylindrical inner cylinder part (152) arranged concentrically with the peripheral edge part (138) is projected on the lower surface of the flat plate part (136), whereby the inner cylinder part A cylinder chamber (160, 165) as a compression chamber is formed between (152) and the peripheral edge (138). And the annular piston main-body part (142) of the said piston (140) is positioned in a cylinder chamber (160,165), as shown in FIG.

  The second housing (150) is a thick disk-shaped member, and is fixed to the inner peripheral surface of the casing (110) on the outer peripheral side thereof, and the first housing ( 135) is also fixed in close contact. The main shaft portion (126) of the drive shaft (125) passes through the central portion of the second housing (150), and the main shaft portion (126) rotates on the inner peripheral surface of the through hole. A sliding bearing (150a) is provided to support it. Further, as will be described in detail later, an oil reservoir (150b) is formed on the surface (upper surface in FIG. 9) of the second housing (150) on the side of the first housing (135). Inside the (150), a part of the drain oil passage (180) communicating with the oil reservoir (150b) is provided, and a throttle valve (185) located on the oil passage is also provided. .

  Further, the compression mechanism (130) includes a blade (145) that divides the cylinder chamber (160, 165) into a high pressure chamber (161, 166) and a low pressure chamber (162, 167), and an annular piston body portion with respect to the blade (145). A rocking bush (156) is provided as a connecting member for rockingly coupling (142) at the parting portion of the annular piston main body (142). The blade (145) is arranged on the radial line of the cylinder chamber (160,165) from the inner peripheral wall surface (the outer peripheral surface of the inner cylinder portion (152)) to the outer peripheral wall surface (the outer cylinder portion). To the peripheral edge (138) (inner peripheral surface), and extends through the parting portion of the annular piston main body (142), and the peripheral edge (138) (hereinafter also referred to as the outer cylinder). And it is being fixed to the inner side cylinder part (152). The blade (145) may be formed integrally with the outer cylinder part (138) and the inner cylinder part (152), or separate members may be attached to both cylinder parts (138, 152). The example shown in FIG. 10 is an example in which another member is fixed to both cylinder portions (138, 152).

  The inner peripheral surface of the outer cylinder portion (138) and the outer peripheral surface of the inner cylinder portion (152) are cylindrical surfaces arranged on the same center, and the cylinder chamber (160, 165) is formed therebetween. . The piston (140) has an outer peripheral surface that is smaller in diameter than the inner peripheral surface of the outer cylinder portion (138), and an inner peripheral surface that is larger in diameter than the outer peripheral surface of the inner cylinder portion (152). Thus, an outer cylinder chamber (160) is formed between the outer peripheral surface of the piston (140) and the inner peripheral surface of the outer cylinder portion (138), and the inner peripheral surface and the inner cylinder portion (152) of the piston (140) are formed. ) Is formed with an inner cylinder chamber (165).

  Specifically, an outer cylinder chamber (160) is formed between the flat plate portion (136), the piston side end plate (141), the outer cylinder portion (138), and the annular piston main body portion (142). An inner cylinder chamber (165) is formed between (136), the piston side end plate (141), the inner cylinder part (152), and the annular piston main body part (142). Further, between the flat plate portion (136), the piston side end plate (141), the bearing portion (143) of the piston (140), and the inner cylinder portion (152), the inner cylinder side (152) has an inner peripheral side. An operation space (168) for allowing the eccentric rotation operation of the bearing portion (143) is formed. The operation space (168) is configured to be a high-pressure space in the present embodiment.

  The piston (140) and the first housing (135) are in a state where the outer peripheral surface of the annular piston body (142) and the inner peripheral surface of the outer cylinder (138) are substantially in contact at one point (strictly Is a micron-order gap, but leakage of refrigerant in the gap is not a problem), and the inner piston surface of the annular piston main body (142) and the inner cylinder portion are positioned 180 ° out of phase with each other. The outer peripheral surface of (152) is substantially in contact with one point.

  The swing bush (156) includes a discharge-side bush (156A) positioned on the high-pressure chamber (161,166) side with respect to the blade (145), and a suction port positioned on the low-pressure chamber (162,167) side with respect to the blade (145). And side bush (156B). The discharge-side bush (156A) and the suction-side bush (156B) are both formed in the same shape with a substantially semicircular cross section, and are arranged so that the flat surfaces face each other. And the space between the opposing surfaces of both bushes (156A, 156B) constitutes a blade groove (158).

  The blade (145) is inserted into the blade groove (158), and the flat surface of the swing bush (156A, 156B) substantially comes into surface contact with the blade (145), so that the swing bush (156A, 156B) The arc-shaped outer peripheral surface is substantially in surface contact with the annular piston main body (142). The swing bushes (156A, 156B) are configured to advance and retreat in the surface direction of the blade (145) with the blade (145) sandwiched between the blade grooves (158). The swing bushes (156A, 156B) are configured such that the annular piston body (142) swings with respect to the blade (145). Therefore, the rocking bush (156) is configured such that the annular piston body (142) can rock with respect to the blade (145) with the center point of the rocking bush (156) as the rocking center, and the ring The piston body (142) is configured to be able to advance and retract in the surface direction of the blade (145) with respect to the blade (145).

  In this embodiment, an example in which both bushes (156A, 156B) are separated from each other has been described. However, both bushes (156A, 156B) may be integrated with each other by being partially connected.

  In the above configuration, when the drive shaft (125) rotates, the annular piston main body (142) moves the center point of the swing bush (156) while the swing bush (156) advances and retreats along the blade (145). Oscillate with the center of oscillation. By this swinging operation, the contact point between the annular piston main body (142) and the first housing (135) is sequentially moved from FIG. 11 (A) to FIG. 11 (H). FIG. 11 is a view showing an operation state of a so-called movable bush type compression mechanism (130), and the annular piston main body (142) is shown at 45 ° intervals from FIG. 11 (A) to FIG. 11 (H). It shows a state of moving in the clockwise direction. At this time, the annular piston body (142) revolves around the drive shaft (125) but does not rotate.

  The first housing (135) is provided with a suction port (139) communicating with the suction pipe (115), and one end side of the suction port (139) is a low pressure chamber (162) of the outer cylinder chamber (160). Is open. The annular piston body (142) has a through hole (153) that communicates the low pressure chamber (162) of the outer cylinder chamber (160) and the low pressure chamber (167) of the inner cylinder chamber (165). Has been.

  The first housing (135) is formed with an outer discharge port (154) and an inner discharge port (155). Each of these discharge ports (154, 155) penetrates the flat plate portion (136) of the first housing (135) in the axial direction thereof. The lower end of the outer discharge port (154) is opened to face the high pressure chamber (161) of the outer cylinder chamber (160), and the lower end of the inner discharge port (155) is the high pressure chamber (166) of the inner cylinder chamber (165). ). On the other hand, these discharge ports (154, 155) are provided with discharge valves (not shown) for opening and closing the discharge ports (154, 155).

  The annular piston main body part (142) of the piston (140) and the tip end face (the upper end face in FIG. 9) of the bearing part (143) are both in sliding contact with the flat plate part (136) of the first housing (135). On the other hand, the front end surface (lower end surface in FIG. 9) of the inner cylinder portion (152) of the first housing (135) is also in sliding contact with the end plate portion (141) of the piston (140). Accordingly, the cylinder chamber (160, 165) formed by the inner cylinder part (152) of the first housing (135) and the piston (140) is in an airtight state. In addition, although mentioned later in detail, in order to hold | maintain this airtight state, it is comprised so that pressing force may act on the said piston (140) from the back side.

  As shown in FIG. 9, a seal ring (170) is provided on the upper surface of the second housing (150) so as to correspond to the central portion of the end plate portion (141) of the piston (140). That is, the seal ring (170) is provided so as to divide the space between the second housing (150) and the piston (140) in the radial direction.

  The space on the inner peripheral side of the seal ring (170) communicates with the high-pressure space (S2 ′) in the casing (110), and the through hole of the drive shaft (125) extends from the storage part (159). (125a) The high-pressure lubricating oil that has passed through the interior is supplied. That is, since the space inside the seal ring (170) is in a high pressure state, back pressure that presses the piston (140) toward the first housing (135) acts.

  Here, as with the scroll compressor (1) according to the first embodiment, the rotary compressor (101) according to the present embodiment also causes the piston (140) to move due to the internal pressure of the cylinder chamber (160, 165). A separation force that separates from the first housing (135) is generated. On the other hand, by applying the pressing force as described above to the piston (140), the piston (140) can be prevented from separating from the first housing (135), and the piston (140 140) and the cylinder chamber (160, 165) formed by the inner cylinder part (152) of the first housing (135) are kept airtight.

  On the other hand, the space on the outer peripheral side of the seal ring (170) is a back pressure space (S3 '), and the lubricant that enters beyond the seal ring (170) and the bearing from the bearing through the compression chambers (160, 165). Due to the leaked lubricating oil, the pressure in the space becomes an intermediate pressure that is higher than the suction port (139) and lower than the high-pressure space (S2 ′) in the casing (110). Thus, the pressure in the back pressure space (S2 ′) also acts to press the piston (140) from the back side.

  Incidentally, in the rotary compressor (101) configured as described above, when the pressure difference between the pressure in the casing (110) and the suction port is small, the back pressure of the piston (140) is sufficiently high. Since it is not high, the behavior of the piston (140) becomes unstable. On the other hand, in order to stabilize the behavior of the piston (140), as in the first embodiment, the diameter of the seal ring (170) is increased to increase the pressing force acting on the piston (140). Can be considered. However, with such a configuration, when the difference between the pressure in the casing (110) and the suction pressure is small, there is no problem because a large pressing force of the piston (140) is necessary, but there is no problem in the casing (110). When the difference between the suction pressure and the suction pressure is large, a sufficient pressing force can be obtained even if the diameter of the seal ring (170) is small. This leads to an increase in friction loss.

  Therefore, even in this embodiment, when the behavior of the piston (140) is unstable, attention is paid to high-pressure lubricating oil leaking from between the piston (140) and the first housing (135). The greater the amount of oil leaked, the greater the pressure loss when the lubricating oil is discharged from the back pressure space (S3 ') to the outside, and the behavior of the piston (140) is stable and the amount of oil leaked is small By reducing the pressure loss, the pressure in the back pressure space (S3 ′) is not increased unnecessarily, and the behavior of the piston (140) is stabilized without increasing the friction loss. I made it.

  Specifically, an oil reservoir (150b) is provided on the back pressure space (S3 ′) side surface of the second housing (150) so as to form a part of the back pressure space (S3 ′), and Inside the second housing (150) and the first housing (135), the oil reservoir (150b) and a suction port (139) as a low pressure space (S1 ′) formed in the first housing (135) are provided. A communicating drain oil passage (180) was provided. The drain oil passage (180) is open at a predetermined height from the bottom surface with respect to the oil reservoir (150b). Further, a differential pressure is generated on the passage (181) in the second housing (150) constituting a part of the drain oil passage (180) by the lubricating oil flowing in the drain oil passage (180). A throttle valve (185) is provided for this purpose.

  As a result, when the behavior of the piston (140) becomes unstable, the lubricating oil leaked from between the piston (140) and the first housing (135) is contained in the back pressure space (S3 ′). It accumulates in the oil reservoir (150b). When the lubricating oil is accumulated in the oil reservoir (150b) to a position higher than the opening position of the discharged oil passage (180), the discharged oil passage (180) is filled with the lubricating oil. The back pressure space (S3 ′) is airtight. Then, the refrigerant dissolved in the high-pressure lubricating oil in the back pressure space (S3 ′) foams and the pressure in the back pressure space (S3 ′) rises. It can be pressed against the housing (135) side to stabilize the behavior of the piston (140). Thereafter, the lubricating oil in the oil reservoir (150b) is discharged until the oil level becomes lower than the opening height position of the discharge oil passage (180) due to the pressure in the back pressure space (S3 ′). It is discharged into the suction port (139) through the oil passage (180). The pressure in the back pressure space (S3 ′) at this time increases as the amount of lubricating oil passing through the throttle valve (185) increases.

  On the other hand, when the behavior of the piston (140) is stable, the amount of lubricating oil leaking into the back pressure space (S3 ′) is small, so the pressure difference generated before and after the throttle valve (185) is Therefore, the pressure in the back pressure space (S3 ′) hardly increases, and it is possible to prevent the piston (140) from being pushed against the first housing (135) and increasing the friction loss.

-Driving action-
Next, the operation of the compressor (101) will be described.

  First, when the electric motor (120) is started, the rotation of the rotor (122) is transmitted to the piston (140) of the compression mechanism (130) via the drive shaft (125). Then, the swinging bush (156A, 156B) reciprocates (advances and retreats) along the blade (145), and the annular piston main body (142) and the swinging bush (156A, 156B) become integrated. And swinging the blade (145). At this time, the swing bushes (156A, 156B) substantially make surface contact with the annular piston main body (142) and the blade (145). Then, the annular piston main body (142) revolves while swinging with respect to the outer cylinder (138) and the inner cylinder (152), and the compression mechanism (130) performs a predetermined compression operation.

  Specifically, in the outer cylinder chamber (160), the volume of the low pressure chamber (162) is almost the minimum in the state of FIG. 11B, and from here the drive shaft (125) rotates clockwise in the figure. When the volume of the low pressure chamber (162) increases as the state changes from 11 (C) to FIG. 11 (A), the refrigerant passes through the suction pipe (115) and the suction port (139). Inhaled into the low pressure chamber (162).

  When the drive shaft (125) makes one revolution and enters the state of FIG. 11 (B) again, the suction of the refrigerant into the low pressure chamber (162) is completed. The low pressure chamber (162) is now a high pressure chamber (161) in which the refrigerant is compressed, and a new low pressure chamber (162) is formed across the blade (145). When the drive shaft (125) further rotates, suction of the refrigerant is repeated in the low pressure chamber (162), while the volume of the high pressure chamber (161) is reduced, and the refrigerant is compressed in the high pressure chamber (161). When the pressure in the high pressure chamber (161) reaches a predetermined value and the differential pressure with respect to the discharge space reaches a set value, the valve is opened by the high pressure refrigerant in the high pressure chamber (161), and the high pressure refrigerant is discharged from the discharge space to the casing (110). It flows out into the high-pressure space (S2 ').

  In the inner cylinder chamber (165), the volume of the low-pressure chamber (167) is almost minimum in the state of FIG. 11 (F), and from here the drive shaft (125) rotates clockwise in FIG. 11 (G). When the volume of the low pressure chamber (167) increases as the state changes to the state of FIG. 11 (E), the refrigerant flows into the suction pipe (115), the suction port (139), and the through hole (144). And is sucked into the low pressure chamber (167) of the inner cylinder chamber (165).

  When the drive shaft (125) makes one revolution and enters the state of FIG. 11 (F) again, the suction of the refrigerant into the low pressure chamber (127) is completed. This low pressure chamber (127) is now a high pressure chamber (126) in which the refrigerant is compressed, and a new low pressure chamber (127) is formed across the blade (145). When the drive shaft (125) further rotates, the suction of the refrigerant is repeated in the low pressure chamber (167), while the volume of the high pressure chamber (166) decreases, and the refrigerant is compressed in the high pressure chamber (166). When the pressure in the high pressure chamber (166) reaches a set value when the pressure in the high pressure chamber (166) reaches a set value, the valve is opened by the high pressure refrigerant in the high pressure chamber (166), and the high pressure refrigerant is discharged from the discharge space to the casing (110). It flows out into the high-pressure space (S2 ').

  In the outer cylinder chamber (160), the refrigerant starts to be discharged almost at the timing shown in FIG. 11E, and in the inner cylinder chamber (165), the discharge starts almost at the timing shown in FIG. That is, the discharge timing of the outer cylinder chamber (160) and the inner cylinder chamber (165) differ by approximately 180 °. The high-pressure refrigerant compressed in the outer cylinder chamber (160) and the inner cylinder chamber (165) and flowing into the high-pressure space (S2 ') in the casing (110) is discharged from the discharge pipe (114) and is condensed in the refrigerant circuit. After the expansion stroke and the evaporation stroke, the air is again sucked into the compressor (101).

  Here, in the space between the piston (140) and the second housing (150), the inner space defined by the seal ring (170) communicates with the high-pressure space (S2 ′). Therefore, it is in a high pressure state, and the piston (140) is pressed from the back side to the first housing (135) side. This pressing force is a force in a direction opposite to the separation force due to the internal pressure of the compression chamber (160, 165).

  On the other hand, the lubricating oil in the reservoir (159) is pushed upward in the through hole (125a) of the drive shaft (125) by the centrifugal pump action at the lower end of the drive shaft (125), and the compression mechanism (130) The sliding bearings (137a, 150a) and the space between the piston (140) and the second housing (150) are provided in the space on the inner peripheral side of the seal ring (170).

  By the way, when the pressure difference between the high-pressure space (S2 ′) and the suction port (139) is small, the pressing force acting on the piston (140) is not sufficiently large with respect to the separation force. The behavior of the piston (140) becomes unstable.

  Then, the lubricating oil leaks into the back pressure space (S3 ′) from between the sliding surfaces of the piston (140) and the first housing (135), and is formed in the back pressure space (S3 ′). The leaked lubricating oil accumulates in the oil reservoir (150b). When a predetermined amount or more of lubricating oil is accumulated in the oil reservoir (150b) and the oil level reaches the opening of the discharge oil passage (180) communicating with the suction port (139), the oil The lubricating oil in the reservoir (150b) enters the discharge oil passage (180), and at least a part of the discharge oil passage (180) is filled with the lubricating oil.

  At this time, pressure loss occurs before and after the throttle valve (185) provided in the discharge oil passage (180) according to the amount of lubricating oil leaked, and the pressure in the back pressure space (S3 ′) is reduced. To rise. Thereby, the pressing force of the piston (140) can be ensured, and the behavior of the piston (140) can be stabilized.

  Conversely, if the pressure in the back pressure space (S3 ′) increases too much, the amount of lubricating oil leaking from between the sliding surfaces of the first housing (135) and the piston (140) decreases, and the throttle By reducing the amount of lubricating oil passing through the valve (185), the differential pressure before and after the throttle valve (185) is reduced, and thus the pressure in the back pressure space (S3 ′) is reduced.

  In this way, when the behavior of the piston (140) becomes unstable, the pressure of the back pressure chamber (S3 ′) increases, and when the behavior of the piston (140) stabilizes, the back pressure chamber (S3 ′) The pressure in the back pressure chamber (S3 ′) is automatically adjusted to the minimum pressure that stabilizes the behavior of the piston (140), and the pressing force of the piston (140) is reduced. It is possible to prevent an unnecessary increase.

  On the other hand, when the difference between the pressure in the high-pressure space (S2 ′) and the suction pressure is large, the pushing force of the piston (140) is sufficient, so the behavior of the piston (140) is stable, The amount of lubricating oil leaking from between the sliding surfaces of the first housing (135) and the piston (140) is small, and the amount of lubricating oil passing through the throttle valve (185) is small. Thus, almost no differential pressure is generated, so that the lubricating oil is discharged to the suction port (139) without increasing the pressure in the back pressure space (S3 ′).

  As described above, the lubricating oil discharged to the suction port (139) is sucked into the compression mechanism (120) together with the refrigerant, compressed in the cylinder chamber (160, 165), and then in the casing (110). It is discharged into the high-pressure space (S2 ′) and returns to the reservoir (159).

-Effect of Embodiment 2-
As described above, according to the present embodiment, the oil reservoir (150b) is provided in the back pressure space (S3 ′) located on the back side of the piston (140), and the oil reservoir (150b) By providing the discharge oil passage (180) communicating with the suction port (139) as the space (S1 '), the piston (140) and the first housing become more unstable when the behavior of the piston (140) becomes unstable. The amount of lubricating oil leaking into the back pressure space (S3 ') from between the sliding surfaces with (135) increases and accumulates in the oil sump (150b), and the low pressure space from the drain oil passage (180). (S1 ') increases the amount of oil discharged. At this time, when the lubricating oil passes through the throttle valve (185) provided in the drain oil passage (180), pressure loss occurs before and after the throttle valve (185), and the larger the amount of drained oil, that is, The more unstable the behavior of the piston (140), the higher the pressure in the back pressure space (S3 ′) can be.

  On the other hand, when the behavior of the piston (140) is stable, the amount of lubricating oil leaking from between the sliding surfaces of the piston (140) and the first housing (135) is small. The pressure loss due to the throttle valve (185) of 180) is reduced, and the pressure in the back pressure space (S3 ′) does not become higher than necessary. That is, when the behavior of the piston (140) is stable, the pressing force to the piston (140) increases, and the friction loss between the piston (140) and the first housing (135) increases. Can be prevented.

  Thus, in the above-described configuration, the pressure of the back pressure space (S3 ′) is adjusted according to the behavior of the piston (140), not the pressure of the back pressure space (S3 ′) or the high pressure space (S2 ′). To stabilize the behavior of the piston (140).

  Therefore, while stabilizing the behavior of the piston (140), it is possible to prevent the frictional loss between the piston (140) and the first housing (135) from increasing and the operating efficiency from deteriorating. That is, the behavior of the piston (140) can be stabilized without increasing the diameter of the seal ring.

<< Other Embodiments >>
Each of the above embodiments may have the following configuration.

  In each of the above embodiments, the compression mechanism (20, 130) and the motor (31, 120) are vertically placed scroll compressors connected by a drive shaft (32, 125) extending in the vertical direction. It may be a horizontal scroll compressor in which the mechanism and the motor are connected by a drive shaft extending in the horizontal direction.

  The first embodiment is based on a high and low pressure dome type scroll compressor in which a low pressure space (S1) and a high pressure space (S2) are provided in a casing (10). In the second embodiment, the casing is a casing. (10) It is premised on a high-pressure dome type compressor in which only the high-pressure space (S2 ′) is provided. However, the present invention is not limited to this. For example, in the first embodiment, the high-pressure dome type scroll compressor is used. Alternatively, in the second embodiment, a high-low pressure dome type compressor may be used.

  Further, in the first embodiment, the oil drain pipe (42) is used to discharge the lubricating oil from the oil reservoir (23c) to the low pressure space (S1). However, the present invention is not limited to this, and the low pressure space (S1) Any configuration may be used as long as the lubricating oil can be discharged. That is, for example, a discharge passage that opens to the bottom surface of the oil reservoir (23c) may be provided, and discharged from the discharge passage to the low-pressure space (S1).

  Furthermore, in the second embodiment, in order to discharge the lubricating oil from the oil reservoir (150b) to the suction port (139), a discharge oil passage (in the first housing (135) and the second housing (150)) 180), but is not limited to this. As in the first embodiment, a part of the drain oil passage (180) is positioned at the lower end in the oil reservoir (150b). You may make it comprise with the waste oil pipe.

  In each of the above embodiments, the space communicating with the back pressure space (S3, S3 ′) and the drain oil passage (43, 180) is the low pressure space (S1, S1 ′) formed in the casing (10, 110). However, the space is not limited to this, and may be a space provided outside the casing (10, 110). That is, for example, the lubricating oil or gas in the back pressure space (S3, S3 ′) may be discharged outside the casing (10, 110).

  Furthermore, in Embodiment 1 above, the variable throttle valve (44) is provided in the drain oil passage (43), but this is not restrictive, and the variable throttle valve (44) may not be provided. In this case, the cross-sectional area of the discharge oil passage (43) cannot be controlled by the differential pressure, but the fluid resistance of the oil passage (43) is set to a predetermined value by adjusting the cross-sectional area of the discharge oil passage (43). Thus, when the behavior of the movable scroll (22) becomes unstable, the inside of the back pressure space (S3) can be set to a predetermined pressure.

  As described above, according to the present invention, an oil reservoir is provided in the back pressure space, and the back pressure is increased between the oil reservoir and the low pressure space according to the amount of lubricating oil flowing into the oil reservoir. By providing the communication path for adjusting the pressure in the space, the behavior of the second member can be stabilized without increasing the friction loss between the first member and the second member that rotate relatively eccentrically. For example, it is particularly useful for a rotary compressor in which lubricating oil is supplied between sliding surfaces of the first member and the second member.

It is a longitudinal cross-sectional view of the rotary compressor which concerns on Embodiment 1 of this invention. It is a partial expanded sectional view which expands and shows a compression mechanism among the rotary compressors of FIG. (A) Longitudinal sectional view of variable throttle valve when pressure in high pressure space is low, (B) Cross sectional view taken along line IIIb-IIIb in (A), (C) Graph showing the relationship between differential pressure and valve opening. . FIG. 4 is a diagram corresponding to FIG. 3 when the pressure in the high-pressure space is higher than in the case of FIG. 3. FIG. 5 is a view corresponding to FIG. 3 when the pressure in the high-pressure space is higher than in the case of FIG. 4. FIG. 6 is a view corresponding to FIG. 3 of a variable throttle valve according to a modification of the first embodiment. FIG. 6 is a view corresponding to FIG. 4 of a variable throttle valve according to a modification of the first embodiment. FIG. 6 is a view corresponding to FIG. 5 of a variable throttle valve according to a modification of the first embodiment. 4 is a longitudinal sectional view of a rotary compressor according to Embodiment 2. FIG. It is a cross-sectional view which shows the principal part of a compression mechanism. It is a cross-sectional view showing the operation of the compression mechanism.

Explanation of symbols

1,101 Rotary compressor
10,110 casing
21 Fixed scroll (first member)
21a End plate
21b Fixed wrap (wrap)
22 Movable scroll (second member)
22a End plate
22b Movable wrap (wrap)
23 frames
23c Oil reservoir
42 Oil drain pipe
43,180 Oil discharge passage (communication passage)
44 Variable throttle valve (fluid resistance changing means)
44a Valve chamber
44b Disc
135 First housing (first member)
138 Peripheral part (cylinder)
140 Piston (second member)
142 Annular piston (piston)
145 blade
152 Inner cylinder (cylinder)
160,165 Cylinder chamber (compression chamber)
161,166 High pressure chamber
162,167 Low pressure chamber
185 throttle valve
S1, S1 'Low pressure space
S2, S2 'High pressure space
S3, S3 'Back pressure space

Claims (8)

A first member (21,135) and a second member (22,140) that are relatively eccentrically rotated while being pressed against each other are provided, and a back pressure space (S3, S3) is provided on the back side of the second member (22,140). ') Is formed and the space (S2, S2') is higher than the back pressure space (S3, S3 ') with respect to the thrust surface between the first member (21, 135) and the second member (22, 140). A rotary compressor (1,101) configured to supply lubricating oil from
The back pressure space (S3, S3 ′) is provided with an oil reservoir (23c, 150d) where the lubricating oil leaked from the thrust surface is accumulated,
Between the oil reservoir (23c, 150d) and the lower pressure space (S1, S1 ') than the back pressure space (S3, S3'), there is lubricating oil for the oil reservoir (23c, 150d). A rotary compressor characterized in that a communication passage (43, 180) is provided for adjusting the pressure in the back pressure space (S3, S3 ') in accordance with the amount of inflow. In claim 1,
In the communication passage (43,180), when a predetermined amount or more of lubricating oil is accumulated in the oil reservoir (23c, 150d), at least a part of the communication passage (43,180) in the passage length direction is covered with the lubricating oil. A rotary compressor characterized by being configured to be satisfied. In any one of Claim 1 or 2,
The communication path (43) includes a fluid resistance of the communication path (43) according to a differential pressure between the high pressure space (S2) and the back pressure space (S3) or the low pressure space (S1). The rotary compressor is provided with fluid resistance changing means (44) for changing the pressure. In claim 3,
The fluid resistance changing means (44) reduces the fluid resistance of the communication path (43) when the differential pressure is greater than or equal to a predetermined value, while the communication path when the differential pressure is less than the predetermined value. (43) A rotary compressor characterized by being configured to increase the fluid resistance. In any one of Claim 3 or 4,
The rotary compressor according to claim 1, wherein the fluid resistance changing means (44) is a variable throttle valve configured to be able to switch a cross-sectional area of the communication passage (43) by the differential pressure. In claim 5,
The variable throttle valve (44) has one side of the valve chamber (44a) partitioned by the valve body (44b) so that the valve body (44b) can reciprocate in the valve chamber (44a). (S2), and the other side of the valve chamber (44a) communicates with either the back pressure space (S3, S3 ′) or the low pressure space (S1). . In any one of Claims 1-6,
The rotary compressor according to claim 1, wherein the first and second members (21, 22) are scroll members in which spiral wraps (21b, 22b) are provided on an end plate (21a, 22a). In any one of Claim 1 or 2,
The first member (135) is constituted by a cylinder (152,138) having an annular cylinder chamber (160,165),
The second member (140) is accommodated in the cylinder chamber (160, 165) in an eccentric state with respect to the cylinder (152, 138), and the cylinder chamber (160, 165) is divided into an outer compression chamber (160) and an inner compression chamber. (165) and is constituted by an annular piston,
A blade (145) that partitions each compression chamber (160,165) into a high pressure side (161,166) and a low pressure side (162,167) is provided across the cylinder (152,138) and the piston (140). Rotary compressor to do.

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