CN106168212B

CN106168212B - scroll compressor

Info

Publication number: CN106168212B
Application number: CN201610258465.6A
Authority: CN
Inventors: 三坂令; 茗原将史
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2015-05-22
Filing date: 2016-04-22
Publication date: 2021-01-01
Anticipated expiration: 2036-04-22
Also published as: JPWO2016189598A1; CN106168212A; JP6395929B2; WO2016189598A1; CN205638916U

Abstract

The present invention relates to a scroll compressor. The base plate of the orbiting scroll has a pressure path that communicates the boss outer space with the innermost chamber located radially innermost of the plurality of compression chambers, and when the motor is operated in reverse, refrigerant gas flows from the boss outer space to the innermost chamber through the pressure path, and oil is supplied through the oil supply path due to a decrease in pressure in the boss outer space.

Description

Scroll compressor having a discharge port

Technical Field

The present invention relates to a scroll compressor used for air conditioning, hot water supply, and the like.

Background

A conventional general scroll compressor includes, in a sealed container: a compression mechanism section; a motor that drives the compression mechanism; and a main shaft that transmits the rotational force of the motor to the compression mechanism. The compression mechanism includes: a fixed scroll and an oscillating scroll having a plate-like spiral wrap on a seat plate portion; a stationary frame provided with a stationary base; and a crosshead mechanism that prevents the orbiting scroll from rotating. The fixed scroll and the orbiting scroll are combined so that plate-shaped spiral wraps thereof mesh with each other, thereby forming a plurality of compression chambers for compressing the refrigerant gas. The oscillating scroll is held by a fixed scroll fixed to the sealed container and a fixed frame, and the fixed frame supports an oscillating shaft portion of the main shaft via an oscillating bearing and causes the oscillating scroll to oscillate by rotation of the main shaft.

In this scroll compressor, in a vertical scroll compressor in which a high pressure (discharge pressure) is formed inside a closed casing and a compression mechanism is disposed above a motor, an oil reservoir for storing refrigerating machine oil is provided in a bottom portion of the closed casing, and the oil reservoir is formed to have a high pressure (discharge pressure). As an oil supply method for supplying high-pressure refrigerating machine oil to a compression mechanism portion located at an upper portion in a closed casing, there is a differential pressure oil supply method. The method is as follows: a space (for example, a space outside the orbiting scroll boss) having a pressure lower than the discharge pressure is formed near the compression mechanism portion of the main shaft, and oil is supplied by a pressure difference with the high-pressure oil reservoir. According to this differential pressure oil supply system, the refrigerating machine oil in the oil reservoir rises by a differential pressure mainly in an oil supply path formed to penetrate in the axial direction of the main shaft, flows out from an upper end opening of the oil supply path to an inner space of the orbiting scroll boss (hereinafter referred to as a boss inner space), and is then supplied to an outer space of the orbiting scroll boss (hereinafter referred to as a boss outer space).

However, for example, a wiring error (wiring error to a terminal of a unit (so-called reverse phase in which the order of phases of a three-phase power supply is disordered)) may occur at the time of a unit (for example, an air conditioner) installation process. Even if such a wiring error occurs, the reverse phase relay is normally operated during driving so as not to supply electric power to the scroll compressor, but the reverse phase relay is prevented from short-circuiting or falling off, and the scroll compressor may be forcibly started. In this case, as the scroll compressor, reverse rotation opposite to the normal rotation, in other words, reverse rotation operation is performed.

When the motor of the scroll compressor continuously performs a reverse rotation operation, the compression mechanism section does not function as a compressor for compressing the refrigerant, but operates as an expander for expanding the refrigerant. When the reverse rotation operation is involved, the compression mechanism does not perform the compression operation, and therefore, the high-pressure gas to be discharged from the compression chamber into the closed casing is not discharged into the closed casing when the compression operation is performed, and the pressure in the closed casing does not rise. Therefore, a pressure difference is not generated between the space outside the boss portion and the inside of the closed casing. Therefore, the scroll compressor of the differential pressure oil supply system has the following problems: the sliding portions in the compression mechanism are not supplied with oil, and the main shaft and the oscillating shaft are burned due to poor lubrication of the bearings of the compression mechanism.

However, among scroll compressors that employ a differential pressure oil supply method are the following scroll compressors: a suction check valve mechanism that prevents a refrigerant from flowing backward from a refrigerant suction port to a suction pressure space is provided between a refrigerant suction port of the fixed scroll, the refrigerant suction port communicating with the compression chamber, and the suction pressure space communicating with a suction pipe in the closed casing (see, for example, patent documents 1 and 2). In such a scroll compressor, when the scroll compressor is operated in the reverse rotation, the pressure decreases from the innermost portion (innermost chamber) to the outermost portion (outermost chamber) of the compression chamber in the compression mechanism portion. Further, since the refrigerant that has reached the outermost chamber closes the return path by the suction check valve mechanism, the pressure in the outermost chamber increases, while the pressure in the compression chamber immediately before reaching the outermost chamber decreases as compared with the pressure in the innermost chamber.

In

patent documents

1 and 2, a path is provided in such a manner that an intermediate pressure chamber (a chamber formed between an outermost portion (outermost chamber) of the compression chamber and the innermost chamber) whose pressure is reduced as compared with the innermost chamber communicates with a space outside the boss portion. Then, by guiding the pressure from the boss outside space to the intermediate pressure chamber through the path, the boss outside space is formed into a low-pressure space lower than the pressure inside the sealed container, and a pressure difference is generated between the low-pressure space and the inside of the sealed container even during the reverse rotation operation, thereby enabling the oil supply.

In addition, the following compressors are proposed: a through hole is provided in the center of the seat plate of the oscillating scroll, and a check valve mechanism that allows refrigerant gas to flow from the boss inner space of the oscillating scroll toward the innermost chamber of the compression chamber and prevents refrigerant gas from flowing from the innermost chamber to the boss inner space is provided in the through hole (see, for example, patent document 3). In patent document 3, when the innermost chamber is made negative in pressure by the motor rotating in reverse, the refrigerant is supplied from the boss inner space to the innermost chamber through the check valve mechanism. This relieves the negative pressure in the innermost chamber, and prevents abnormal wear and damage caused by pressing the orbiting scroll against the fixed scroll.

Patent document 1: japanese patent laid-open publication No. 2011-106322

Patent document 2: japanese patent laid-open publication No. 2011-

Patent document 3: japanese Kokai publication Hei-4-91291

According to patent document 1 and patent document 2, the intermediate chamber having a pressure lower than that of the innermost chamber is communicated with the boss outer space, so that a pressure difference is generated between the boss outer space and the inside of the closed container, and oil can be supplied to the compression mechanism portion during the reverse rotation operation.

However, in the case of the compressors of

patent documents

1 and 2, the following configuration is adopted: a discharge valve mechanism is provided at a discharge port formed at a central portion of the fixed scroll, and only allows a unidirectional flow of the refrigerant gas from the innermost chamber (compression chamber) to the internal space of the closed casing through the discharge port, and therefore, there are the following problems. That is, during the reverse rotation operation, the flow of the refrigerant from the inside of the closed casing to the innermost side chamber is blocked by the discharge valve mechanism, and the refrigerant cannot flow into the innermost side chamber from the discharge port. Thus, there are problems as follows: the innermost chamber is in a state of being nearly evacuated, and the fixed scroll and the oscillating scroll are operated in a pressure contact state, so that abnormal abrasion or the like occurs in the plate-shaped spiral wrap, thereby causing a decrease in reliability.

In the case of the compressor described in patent document 3, even when the pressure in the innermost chamber is reduced for some reason during a reverse rotation operation or the like, the refrigerant gas and the refrigerating machine oil flow into the innermost chamber from the boss inner space through the through hole provided in the center portion of the seat plate portion of the orbiting scroll, and the vacuum state in the innermost chamber can be avoided.

However, when the technique of patent document 3 is applied to a scroll compressor employing a differential pressure oil supply system as in

patent documents

1 and 2, the refrigerating machine oil flowing out from the upper end opening of the oil supply path of the main shaft toward the boss inner space does not lubricate the rocking bearing provided in the boss inner space, but flows into the innermost chamber directly together with the refrigerant. Therefore, there are problems as follows: oil cannot be supplied to the oscillating bearing shaft provided in the inner space of the boss portion, and the oscillating shaft portion of the main shaft is burned or the like, thereby lowering reliability.

Disclosure of Invention

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a scroll compressor including a discharge valve mechanism, in which a vacuum state of an innermost chamber can be avoided during a motor reverse rotation operation, and oil can be supplied to a bearing during the motor reverse rotation operation.

The scroll compressor according to the present invention includes: a closed container; a compression mechanism portion which is provided in the sealed container and has a fixed scroll and an oscillating scroll, and in which plate-like spiral wraps provided on respective seat plate portions of the fixed scroll and the oscillating scroll are combined with each other to form a plurality of compression chambers; a motor that drives the compression mechanism; a main shaft that is rotatably inserted through a rocking bearing into a boss provided on a surface of a base plate portion of the rocking scroll on the opposite side of the plate-like spiral tooth, and that is rotated by a motor to thereby cause the rocking scroll to perform a rocking motion; and a discharge valve mechanism which covers a discharge port provided in the fixed scroll and allows the refrigerant gas to flow from the compression chamber to an internal space of the closed casing through the discharge port, and prevents the refrigerant gas from flowing reversely, the main shaft has an oil supply path, the refrigerating machine oil in the closed container is supplied to a sliding part including a compression mechanism part based on the pressure difference between the pressure in the closed container and the pressure of the external space of the boss part by the oil supply path, the base plate part of the swing scroll has a pressure path, the pressure path communicates an outer space of the boss portion with an innermost chamber located radially innermost of the plurality of compression chambers, during the reverse rotation operation of the motor, the refrigerant gas flows from the outer space of the boss portion to the innermost side chamber through the pressure path, and the pressure in the outer space of the boss portion is reduced, thereby supplying oil through the oil supply path.

According to the present invention, since the path for communicating the boss outside space with the innermost chamber is provided in the base plate portion of the orbiting scroll, the vacuum state of the innermost chamber can be avoided by introducing the pressure of the boss outside space into the innermost chamber during the reverse rotation of the motor. Further, the pressure in the space outside the boss is reduced by the flow of the refrigerant from the space outside the boss to the innermost side chamber, and the pressure in the space outside the boss is made lower than the pressure in the closed casing, whereby the differential pressure required for the oil supply can be secured, and therefore a highly reliable scroll compressor capable of supplying the oil to each part of the compressor at the time of the reverse rotation operation can be obtained.

Drawings

Fig. 1 is a schematic cross-sectional view showing a structure of a scroll compressor according to embodiment 1 of the present invention.

Fig. 2 is a schematic cross-sectional view of the compression mechanism portion and its surroundings in fig. 1.

Fig. 3 is a schematic diagram showing a flow of the refrigerating machine oil at the time of differential pressure oil supply and a flow of the pressure in the space outside the boss portion at the time of differential pressure oil supply in the scroll compressor according to embodiment 1 of the present invention.

Fig. 4 is a graph showing a graph a showing a change in the pressure adjustment capability of the boss outer space according to the diameter of the pressure path during the reverse rotation operation of the scroll compressor according to embodiment 1 of the present invention, and a graph B showing a change in the compressor efficiency according to the diameter of the pressure path during the normal rotation operation of the scroll compressor.

Fig. 5 is a schematic cross-sectional view showing a main part of a scroll compressor according to embodiment 2 of the present invention.

Description of reference numerals:

1 … fixed scroll, 1a … seat plate portion, 1b … plate-like spiral teeth, 1c … crosshead guide groove, 1d … discharge port, 2 … oscillating scroll, 2a … seat plate portion, 2b … plate-like spiral teeth, 2c … crosshead guide groove, 2d … boss, 2e … oscillating bearing, 2f … thrust surface, 2g … boss outer space (low pressure space), 2h … pressure path, 2i … plug, 2j … extraction hole, 2k … pressure path check valve mechanism, 2l … plug, 3 … movable frame, 3a … thrust bearing, 3b … surface, 3c … main bearing, 3d … auxiliary main bearing, 3e … upper fitting cylindrical portion, 3f … lower fitting cylindrical portion, 3g … movable frame check valve mechanism, 3h … connecting passage, 4 … fixed frame, 4a … upper fitting cylindrical portion, 4b … lower fitting oil 5 …, freezing cylindrical portion, 6 … main shaft, 6a … swing shaft portion, 6b … main shaft portion, 6c … auxiliary shaft portion, 6d … oil supply path, 7 … auxiliary frame, 7a … auxiliary bearing, 8 … crosshead mechanism, 8a … fixed side key, 8b … swing side key, 8c … crosshead mechanism annular portion, 9 … discharge valve mechanism, 9a … discharge valve, 10 … compression mechanism portion, 11a … white hollow arrow, 12 … suction pipe, 12a … compressor suction space, 13 … discharge pipe, 14 … compression chamber, 14a … compression chamber suction space, 14b … outermost side chamber, 14c … innermost side chamber, 20 … motor, 21 … motor stator, 22 … motor rotor, 100 … compressor, 100a … sealed container, 100b 46 … sealed container internal space.

Detailed Description

Embodiment 1.

Fig. 1 is a schematic cross-sectional view showing a structure of a scroll compressor according to embodiment 1 of the present invention. In fig. 1 and the following drawings, elements denoted by the same reference numerals indicate the same or equivalent elements, and this is common throughout the specification. The embodiments of the constituent elements described throughout the specification are merely exemplary, and are not limited to these descriptions. The level of the temperature, pressure, and the like is not particularly defined in relation to absolute values, but is relatively defined in relation to states, operations, and the like in the system, the device, and the like.

The scroll compressor 100 includes at least a compression mechanism 10 and a motor 20 in a sealed container 100 a. The compression mechanism 10 and the motor 20 are coupled by a main shaft 6, and the main shaft 6 transmits a rotational force generated by the motor 20 to the compression mechanism 10.

Further, the closed casing 100a is provided with: a suction pipe 12 for sucking gas; and a discharge pipe 13 for discharging the compressed gas. The lower portion of the sealed container 100a serves as an oil reservoir for storing the refrigerating machine oil 5, and the refrigerating machine oil 5 stored in the oil reservoir is drawn upward from a lower end opening of an oil supply path 6d formed to penetrate in the axial direction of the main shaft 6 by a differential pressure described later, and the refrigerating machine oil 5 is supplied to the respective sliding portions of the rocking bearing 2e, the main bearing 3c, the auxiliary main bearing 3d, and the compression mechanism 10 through the oil supply path 6 d.

The compression mechanism 10 includes a fixed scroll 1 and an oscillating scroll 2. The fixed scroll 1 includes: a seat plate part 1 a; and a plate-shaped spiral wrap 1b serving as a spiral projection provided upright on one surface of the base plate portion 1a, and the fixed scroll 1 is fixed to the sealed container 100a by a bolt (not shown) or the like. The orbiting scroll 2 includes: a seat plate part 2 a; and a plate-shaped spiral wrap 2b serving as a spiral projection provided upright on one surface of the seat plate portion 2a, and the orbiting scroll 2 is supported to be swingable on a later-described orbiting shaft portion 6a of the main shaft 6. The plate-shaped wrap 1b of the fixed scroll 1 and the plate-shaped wrap 2b of the orbiting scroll 2 are combined to mesh with each other, and a plurality of spaces partitioned by the combined plate-shaped wrap 1b and plate-shaped wrap 2b serve as a plurality of compression chambers 14 for compressing refrigerant gas.

The plurality of compression chambers 14 suck the refrigerant gas from a compression chamber suction space 14a located on the outer periphery of the plurality of compression chambers 14 and communicating with the suction pipe 12 to an outermost chamber 14b located outermost among the plurality of compression chambers 14, and the refrigerant gas is transferred to the center portion with the rotation of the main shaft 6, thereby increasing the pressure of the refrigerant gas.

A discharge port 1d for discharging a refrigerant compressed to a high pressure is formed in the center of the fixed scroll 1. A discharge valve mechanism 9 is disposed at the discharge port 1d, and the discharge valve mechanism 9 covers the discharge port 1d, allows the refrigerant gas to flow from the innermost chamber 14c located radially innermost among the plurality of compression chambers 14 toward the internal space of the closed casing 100a through the discharge port 1d, and prevents the refrigerant gas from flowing backward. The discharge valve mechanism 9 has a discharge valve 9a made of a plate spring, and when the refrigerant is compressed to a predetermined pressure in the compression chamber 14, the discharge valve 9a is pressed against the elastic force thereof to open the discharge valve 9a, thereby opening the discharge port 1 d. The compressed refrigerant is discharged from the opened discharge port 1d to the closed casing internal space 100b, and is discharged to the outside of the scroll compressor 100 through the discharge pipe 13. Therefore, the internal space 100b of the closed casing becomes a high-pressure space.

In the seat plate portion 2a of the orbiting scroll 2, a hollow cylindrical boss portion 2d is formed at the center of a surface (lower surface in fig. 1) opposite to the surface on which the plate-shaped spiral wrap 2b is formed, and a rocking bearing 2e is disposed on the inner surface of the boss portion 2 d. Further, in the seat plate portion 2a, a thrust surface 2f that can press-contact and slide against the thrust bearing 3a of the movable frame 3 is formed on the outer peripheral portion of the same surface (lower surface in fig. 1) as the boss portion 2 d.

Further, an Oldham mechanism (Oldham mechanism)8 is disposed between the fixed scroll 1 and the orbiting scroll 2, thereby preventing the orbiting scroll 2 from rotating and correcting the posture. Specifically, 2, that is, 1 pair of crosshead guide grooves 1c are formed substantially on a straight line on the outer peripheral portion of one surface (lower surface in fig. 1) of the base plate portion 1a of the fixed scroll 1. 2, that is, 1 pair of fixed-side keys 8a of the crosshead mechanism 8 are engaged with the crosshead guide groove 1c so as to be slidable back and forth in the circumferential direction of the main shaft 6.

Further, 2, that is, 1 pair of the crosshead guide grooves 2c having a phase difference of substantially 90 degrees with respect to the crosshead guide groove 1c of the fixed scroll 1 are formed substantially on a straight line in the outer peripheral portion of the seat plate portion 2a of the orbiting scroll 2. 2, that is, 1 pair of rocking side keys 8b of the crosshead mechanism 8 are engaged with the crosshead guide groove 2c so as to be slidable back and forth in the circumferential direction of the main shaft 6. Further, a surface 3b on which the crosshead mechanism annular portion 8c reciprocates is formed outside the thrust bearing 3a of the movable frame 3. In this way, the fixed side key 8a and the swing side key 8b of the crosshead mechanism 8 engage with the crosshead guide groove 1c of the fixed scroll 1 and the crosshead guide groove 2c of the swing scroll 2 so as to be slidable back and forth, thereby preventing the swing scroll 2 from rotating.

The motor 20 includes: a motor stator 21 formed in a ring shape; and a motor rotor 22 supported to be rotatable inside the motor stator 21. The motor rotor 22 is thermally mounted between a sub-shaft portion 6c and a main shaft portion 6b of the main shaft 6, which will be described later.

In the sealed container 100a, the fixed frame 4 and the sub-frame 7 are fixed to the sealed container 100a so as to face each other with the motor 20 interposed therebetween. Further, the movable frame 3 is disposed inside the fixed frame 4, and the main bearing 3c and the auxiliary main bearing 3d are disposed at the centers of the movable frame 3 and the sub-frame 7. The main shaft 6 is rotatably supported by a main bearing 3c, an auxiliary main bearing 3d, and a sub bearing 7a provided at the centers of the movable frame 3 and the sub frame 7.

The main shaft 6 includes an upper swing shaft portion 6a of the main shaft 6, a main shaft portion 6b, and a lower sub shaft portion 6c of the main shaft 6. The oscillating scroll 2 is fitted to the oscillating shaft portion 6a via an oscillating bearing 2e, and the oscillating scroll 2 oscillates by rotation of the main shaft 6. The main shaft portion 6b is fitted to the main bearing 3c, and slides with respect to the main bearing 3c via an oil film generated by the refrigerating machine oil 5.

The fixed frame 4 has a shape in which a plurality of cylindrical portions having different diameters are connected in the axial direction, and is configured such that the diameter decreases in order toward the motor 20 side (lower side in fig. 1). In the fixed frame 4, an upper fitting cylindrical portion 4a on the fixed scroll 1 side (upper side in fig. 1) is engaged with an upper fitting cylindrical portion 3e of the movable frame 3. On the other hand, the lower fitting cylindrical portion 4b on the motor 20 side (lower side in fig. 1) of the fixed frame 4 is engaged with the lower fitting cylindrical portion 3f of the movable frame 3.

The compressor suction space 12a, which is a space surrounded vertically by the base plate 2a of the orbiting scroll 2 and the movable frame 3 and is a space on the outer circumferential side of the thrust bearing 3a, is a compressor suction space 12a in which a gas atmosphere (suction pressure) is sucked. Further, a space surrounded vertically by the seat plate portion 2a of the orbiting scroll 2 and the movable frame 3 and a space on the inner peripheral side of the thrust bearing 3a become a low-pressure space 2g for supplying differential pressure oil. Since the boss 2d of the orbiting scroll 2 is located in the low pressure space 2g and the low pressure space 2g is located outside the boss 2d, the low pressure space 2g is hereinafter referred to as a boss outside space 2 g.

Further, the movable frame 3 is formed with a connection passage 3h penetrating in the axial direction. The upper end of the connection passage 3h communicates with the draw hole 2j of the base plate portion 2a of the orbiting scroll 2, and the lower end of the connection passage 3h communicates with the space between the movable frame 3 and the fixed frame 4. Then, the intermediate pressure in the compression chamber 14 acts as a back pressure of the movable frame 3 via the extraction hole 2j and the connection passage 3h, thereby floating the movable frame 3 and causing the movable frame 3 to perform an operation of pressing the orbiting scroll 2 against the fixed scroll 1. In addition, a movable frame check valve mechanism 3g is provided in the movable frame 3, and this movable frame check valve mechanism 3g allows a one-way flow from the boss outside space 2g to the compressor suction space 12 a.

A pressure path 2h is provided in the seat plate portion 2a of the orbiting scroll 2, and the pressure path 2h connects the innermost chamber 14c and the boss outside space 2g and is a characteristic part of the present invention. The function of the pressure path 2h, which will be described in detail later, is provided to prevent a decrease in pressure of the compression chamber 14 when the compression chamber 14 is in a vacuum state during reverse operation of the scroll compressor 100. Further, the machined hole of the pressure path 2h is closed by a plug 2 i.

Next, the operation of the scroll compressor 100 in the normal rotation operation and the reverse rotation operation will be described.

Fig. 3 is a schematic diagram showing a flow of the refrigerating machine oil at the time of differential pressure oil supply and a flow of the pressure in the space outside the boss portion at the time of differential pressure oil supply in the scroll compressor according to embodiment 1 of the present invention. White hollow arrows 11a in fig. 3 indicate the flow of the refrigerator oil 5 to the compressor parts. The flow of the refrigerating machine oil 5 is the same regardless of the normal rotation operation and the reverse rotation operation of the scroll compressor 100. In fig. 3, the dashed arrows indicate the flow of the refrigerant during the normal rotation operation, and the solid arrows indicate the flow of the refrigerant during the reverse rotation operation.

(in normal rotation)

When electric power is supplied to the motor stator 21, the motor rotor 22 generates torque to rotate the main shaft 6. The orbiting scroll 2 is restricted from rotating by the crosshead mechanism 8 to perform an orbiting motion by the rotation of the main shaft 6. Here, since the normal rotation operation is performed, the gas refrigerant is sucked into the closed casing 100a from the suction pipe 12. The gas refrigerant sucked into the sealed container 100a is taken into the outermost chamber 14b of the plurality of compression chambers 14 formed between the plate-like wrap 1b of the fixed scroll 1 and the plate-like wrap 2b of the orbiting scroll 2 via the refrigerant suction port of the fixed scroll 1. As the orbiting scroll 2 oscillates, the outermost chamber 14b decreases in volume while moving from the outer peripheral portion toward the center. Therefore, the refrigerant gas taken into the outermost chamber 14b is compressed as the volume of the compression chamber 14 decreases. The compressed refrigerant gas is discharged from a discharge port 1d provided in the fixed scroll 1 into the closed casing 100a through a discharge valve mechanism 9. The refrigerant gas discharged into the sealed container 100a is discharged from the discharge pipe 13 to the refrigerant circuit outside the sealed container 100 a.

Here, the boss outside space 2g is affected by the discharge pressure in the closed casing 100a, and the refrigerant is allowed to flow from the boss outside space 2g to the compressor suction space 12a by the movable frame check valve mechanism 3g (dashed arrow in fig. 3). Therefore, at the time of normal rotation operation of the motor 20, the boss outside space 2g is controlled to an intermediate pressure between the suction pressure and the discharge pressure. Thus, during the normal rotation operation, the refrigerating machine oil 5 stored in the lower portion of the sealed container 100a, which is a high-pressure space, rises through the oil supply path 6d due to a pressure difference (an intermediate pressure between the high pressure in the sealed container 100a and the boss outside space 2 g). A plurality of oil supply paths (not shown) are formed in the main shaft 6 so as to extend through the main shaft in the radial direction to communicate with the oil supply path 6d, and the refrigerating machine oil 5 that has risen in the oil supply path 6d is supplied to the sub-bearing 7a, the main bearing 3c, and the auxiliary main bearing 3d through the oil supply paths (not shown). Then, the refrigerating machine oil 5 flowing out from the upper end opening of the oil supply path 6d flows into the boss outside space 2g after being supplied to the rocking bearing 2 e.

(during reverse rotation)

When the scroll compressor 100 is operated in the reverse rotation direction, the main shaft 6 rotates in the direction opposite to that in the normal rotation direction, and therefore, the innermost chamber 14c gradually increases in volume while moving from the center side to the outer peripheral side with the oscillating motion of the oscillating scroll 2, and the refrigerant gas in the innermost chamber 14c expands. In this way, during the reverse rotation operation, the refrigerant in the compression mechanism section 10 is sent in the direction opposite to that during the normal rotation operation, and is collected in one direction with respect to the outermost chamber 14b and the compression chamber suction space 14a, and further with respect to the unit low-pressure space connected to the scroll compressor 100. Therefore, the pressure of the outermost chamber 14b and the compression chamber suction space 14a becomes higher than the pressure of the outermost chamber 14b and the compression chamber suction space 14a during the normal rotation operation. In the reverse rotation operation, the refrigerant gas in the innermost side chamber 14c does not reach the discharge pressure, and therefore the refrigerant gas is not discharged into the closed casing 100a through the discharge port 1 d. Therefore, the pressure in the closed casing 100a does not rise.

Therefore, the pressure of the boss outside space 2g affected by the pressure in the closed casing 100a becomes lower than the pressure of the outermost chamber 14b and the compression chamber suction space 14a, and the movable frame check valve mechanism 3g provided in the movable frame 3 does not operate. In other words, the refrigerant does not flow from the boss outside space 2g to the compression chamber suction space 14 a.

In addition, during the reverse rotation operation, the innermost chamber 14c is not brought to a high pressure as in the normal rotation operation, and therefore the discharge valve mechanism 9 remains closed. Therefore, when the motor 20 is operated in reverse, the innermost compartment 14c and the boss outside space 2g communicating with the innermost compartment 14c become closed spaces. As described above, the refrigerant in the innermost side room 14c is sent in the direction opposite to the normal rotation operation, and the innermost side room 14c is brought into a state close to vacuum or a vacuum state.

As described above, the innermost room 14c is brought into a state close to vacuum or a vacuum state, and the refrigerant gas or the refrigerating machine oil 5 in the boss outside space 2g, or both of them flow into the innermost room 14c from the boss outside space 2g through the pressure path 2h as indicated by solid arrows in fig. 3. This prevents a pressure drop in the innermost compartment 14c, and thus avoids a vacuum state. As a result of the above-described flow from the boss exterior space 2g to the innermost side chamber 14c occurring simultaneously, the pressure in the boss exterior space 2g is reduced as compared with the pressure in the closed casing 100 a. Therefore, the same differential pressure oil supply as that in the normal rotation operation of the compressor is performed.

Here, as in patent document 3, in the case of a structure in which the boss portion "inside" space is made to communicate with the innermost compartment, the oil flowing out from the upper end opening of the oil supply path as described above is directly supplied to the innermost compartment as it is. In this case, since the main shaft and the rocking bearing are not lubricated, there is a possibility that a trouble such as seizure of the main shaft and the rocking bearing occurs. In contrast, in embodiment 1, since the boss portion "outside" space is configured to communicate with the innermost side chamber 14c, the oil flowing out from the upper end opening of the oil supply path 6d flows as follows: the lubricating oil is supplied between the main shaft 6 and the rocking bearing 2e as in the normal rotation operation, lubricates the sliding portion, and then flows into the boss outside space 2 g. Therefore, troubles such as seizure of the main shaft 6 and the rocking bearing 2e can be suppressed.

However, since the pressure path 2h always communicates with the innermost side chamber 14c, the pressure path 2h becomes a so-called Dead space (Dead volume), and a part of the compression work performed by the compression mechanism section 10 leaks to the boss outer space 2 g. This may become an important factor in deterioration of the efficiency of the compressor. To cope with this, the pressure path 2h is preferably set to be not more than 2mm and more than 0 mm.

Fig. 4 is a graph showing a graph a showing a change in the pressure adjustment capability of the boss outer space according to the diameter of the pressure path during the reverse rotation operation of the scroll compressor according to embodiment 1 of the present invention, and a graph B showing a change in the compressor efficiency according to the diameter of the pressure path during the normal rotation operation of the scroll compressor. In fig. 4, the horizontal axis represents the diameter Φ [ mm ] of the pressure path, the right vertical axis represents the pressure adjustment capability [% ] during the reverse rotation operation, and the left vertical axis represents the compressor efficiency [% ].

As shown in the graph B of fig. 4, the compressor efficiency at the time of normal rotation operation of the scroll compressor 100 decreases as the diameter of the pressure path 2h increases. On the other hand, the pressure adjustment capability of the boss outside space 2g at the time of reverse rotation operation of the scroll compressor 100 increases as the diameter of the pressure path 2h increases. The state in which the refrigerant can be supplied to the innermost side chamber 14c in an amount necessary for preventing the inside of the compression chamber 14 from being vacuumed even in the reverse rotation operation is set to "100% pressure adjustment capability". If the compressor adjustment capacity is 90% or more, the refrigerant can be supplied to the innermost chamber 14c even when the reverse rotation operation is involved, and the scroll compressor 100 can be ensured a sufficient time before the compressor stops without being damaged by the vacuum operation. Here, if the reduction in compressor efficiency is less than 1%, the problem will not occur in actual operation. In view of the above, it is preferable to set the pressure path 2h to be equal to or smaller than 2 mm.

As described above, according to embodiment 1, since the boss outside space 2g and the innermost side chamber 14c are configured to communicate with each other through the pressure path 2h, oil supply to each part of the compressor can be performed even during the reverse rotation operation, and abnormal wear of the shaft and the bearing can be prevented. Further, the scroll compressor 100 can be obtained with high reliability, which can avoid the vacuum state of the compression chamber 14 and can prevent abnormal wear of the spiral wrap of the fixed scroll 1 and the orbiting scroll 2.

Embodiment 2.

Embodiment 2 has the following configuration: in the pressure path 2h of embodiment 1, the refrigerant is prevented from flowing from the innermost side room 14c to the boss outer space 2 g.

Fig. 5 is a schematic cross-sectional view showing a main part of a scroll compressor according to embodiment 2 of the present invention. Hereinafter, embodiment 2 will be described mainly with respect to a structure different from that of embodiment 1.

In addition to the scroll compressor 100 according to embodiment 1, the scroll compressor 100 according to embodiment 2 further includes a pressure path check valve mechanism 2k in the pressure path 2 h. The pressure path check valve mechanism 2k allows the refrigerant gas to flow from the boss outer space 2g toward the innermost room 14c, and prevents the reverse flow of the refrigerant gas. Further, a machining hole for disposing the pressure path check valve mechanism 2k is closed by a plug 2 l.

The scroll compressor 100 according to embodiment 2 configured as described above can obtain the same effects as those of embodiment 1, and the following effects can be obtained by providing the pressure path check valve mechanism 2k in the pressure path 2 h. That is, the refrigerant gas can be prevented from leaking from the innermost side chamber 14c to the boss outer space 2g during the normal rotation operation, and the reduction in the compressor efficiency can be prevented.

Further, when the pressure path check valve mechanism 2k is provided in the pressure path 2h at a position close to the innermost room 14c, the dead space of the compression room 14 can be reduced, and the reduction in the compressor efficiency can be further prevented. Therefore, the pressure path check valve mechanism 2k is preferably provided as close as possible to the innermost room 14c within the allowable limits in terms of structure and material strength.

As described above, the scroll compressor 100 according to embodiment 2 can provide a compressor having the same reliability as the scroll compressor 100 shown in embodiment 1 and having higher efficiency.

Claims

1. A scroll compressor is characterized by comprising:

a closed container;

a compression mechanism portion which is provided in the closed container and has a fixed scroll and an oscillating scroll, and in which plate-like spiral teeth provided on respective seat plate portions of the fixed scroll and the oscillating scroll are combined with each other to form a plurality of compression chambers;

a motor that drives the compression mechanism;

a main shaft that is rotatably inserted through a swing bearing into a boss portion provided on a surface of the base plate portion of the swing scroll opposite to the plate-shaped spiral wrap, and that is rotated by the motor to thereby cause the swing scroll to swing; and

a discharge valve mechanism that covers a discharge port provided in the fixed scroll, allows a refrigerant gas to flow from the compression chamber to an internal space of the closed casing through the discharge port, and prevents a reverse flow of the refrigerant gas,

the main shaft has an oil supply path that penetrates the main shaft in an axial direction of the main shaft and supplies refrigerating machine oil stored in an oil storage portion at a lower portion of the closed casing to a sliding portion including the compression mechanism portion based on a pressure difference between a pressure in the closed casing and a pressure in an external space of the boss portion,

the seat plate portion of the oscillating scroll has a pressure path that communicates an outer space of the boss portion with an innermost chamber located innermost in a radial direction among the plurality of compression chambers,

a pressure path check valve mechanism that allows the refrigerant gas to flow from an outer space of the boss portion toward the innermost side chamber and prevents a reverse flow of the refrigerant gas is provided in the pressure path,

the rocking bearing is disposed on an inner side surface of the boss portion, and the oil flowing out from the upper end opening of the oil supply path is supplied between the main shaft and the rocking bearing, and flows into an outer space of the boss portion after lubricating the sliding portion,

during a reverse rotation operation of the motor, the refrigerant gas flows from the space outside the boss portion to the innermost chamber through the pressure path, and the pressure in the space outside the boss portion is reduced to supply oil through the oil supply path.