JP2009008007A - Scroll compressor - Google Patents

Abstract

When a dimensional change due to thermal expansion occurs, there is a risk that seizure will occur due to contact between the top surface of the fixed scroll and the bottom surface of the orbiting scroll.
A communication hole (31) communicating from the high pressure region (30) to the compression chamber (15) is provided in the end plate (13a) of the orbiting scroll (13), and the communication hole (31) is formed on both sides of the wrap (12b) of the fixed scroll (12). By facing only one of the compression chambers, the oil can be directly supplied to a portion where seizure is likely to occur.
[Selection] Figure 3

Description

  The present invention relates to a scroll compressor used in a cooling device such as a cooling / heating air conditioner or a refrigerator, or a heat pump type hot water supply device.

  2. Description of the Related Art Conventionally, scroll compressors used in refrigeration air conditioners and refrigerators generally form a compression chamber between the fixed scroll and the orbiting scroll in which the spiral wrap rises from the end plate, and the orbiting scroll is rotated by a rotation restraint mechanism. When it is swung along a circular orbit under the constraint of the above, suction, compression, and discharge are performed by moving the compression chamber while changing the volume. During operation, pressure is applied to the orbiting scroll from the back, and the inside is stuck to the fixed scroll by applying a high pressure inside and an intermediate pressure outside the annular seal member. . Further, since the working fluid is compressed toward the center and becomes a high-temperature and high-pressure state, the orbiting scroll and the fixed scroll are also heated at the center, resulting in a dimensional change due to thermal expansion. In particular, this phenomenon appears prominently under high-load operating conditions, and there is a risk that seizure will occur due to the contact between the top surface of the fixed scroll and the bottom surface of the orbiting scroll. Therefore, there is a method in which a communication passage is provided in the end plate of the orbiting scroll and oil is supplied to the compression chamber (see, for example, Patent Document 1).

FIG. 10 is a cross-sectional view of a conventional scroll compressor described in Patent Document 1. In FIG. As shown in FIG. 10, the oil on the bottom surface of the sealed container 110 is guided to the upper part through the inside 106 b of the shaft 106. The oil guided to the upper end of the shaft 106 reaches the high pressure region 114a via the eccentric shaft portion 102e. The oil reaching the high pressure region 114a leaks through the seal member 115 and reaches the back pressure chamber 114b. The back pressure chamber 114b and the compression chamber 107 communicate with each other through the communication hole 111, and the back pressure chamber 114b is maintained at a predetermined intermediate pressure.
JP-A-8-121366

  In the conventional configuration, since the position of the communication hole 111 is adjusted so that the back pressure chamber 114b has a predetermined intermediate pressure, oil is directly supplied to the compression chamber 107 in the vicinity of the center portion in a high temperature and high pressure state. I'm not doing it. That is, when the oil supplied to the compression chamber 107 reaches the vicinity of the center, it receives the compression heat of the working fluid, and as a result, the viscosity of the oil is lowered and the effect of lubrication is reduced.

  Further, since the amount of oil supplied to the back pressure chamber 114b is the amount of leakage from the seal member 115, it depends on the assembly and component accuracy and may vary greatly from compressor to compressor. In other words, there may be a compressor that can supply sufficient oil to the compression chamber 107 and a compressor that does not.

  The scroll compressor of the present invention can prevent seizure of the top surface of the fixed scroll and the bottom surface of the orbiting scroll by supplying oil stably to the compression chamber that is in a high temperature and high pressure state. An object of the present invention is to provide a scroll compressor that ensures high reliability.

In order to solve the above-described conventional problems, the scroll compressor according to the present invention forms a compression chamber between the fixed scroll and the orbiting scroll in which the spiral wrap rises from the end plate, and forms an annular ring on the back of the orbiting scroll. A seal member is arranged, and the seal member is divided into an inner high pressure region and an outer back pressure chamber, and the orbiting scroll is brought into contact with the fixed scroll by applying suction pressure or a constant intermediate pressure to the back pressure chamber. By providing a rotation restraining mechanism on the back, the orbiting scroll revolves along a circular orbit, which causes the compression chamber to move toward the center while changing the volume, and scroll compression that performs a series of operations of suction, compression, and discharge In the machine, communication holes from the high pressure area to the compression chamber are provided in the end plate of the orbiting scroll, and the communication holes are formed on both sides of the fixed scroll lap. Those that face only one of the compression chambers of the compression chamber to be.

  According to this configuration, oil can be directly supplied from the high pressure region on the back of the orbiting scroll to the compression chamber that is in a high temperature and high pressure state, and further to the top surface of the wrap of the fixed scroll where seizure is likely to occur. In addition, since the oil is always supplied stably to the high pressure region, the amount of oil supplied to the compression chamber is also stable, and the influence of individual compressor differences due to assembly and component accuracy can be reduced. That is, it is possible to provide a scroll compressor that ensures high reliability.

  The scroll compressor of the present invention can prevent seizure of the top surface of the fixed scroll and the bottom surface of the orbiting scroll by supplying oil stably to the compression chamber that is in a high temperature and high pressure state. Therefore, it is possible to provide a scroll compressor that ensures high reliability.

  In the first aspect of the present invention, the fixed scroll and the orbiting scroll where the spiral wrap rises from the end plate are meshed to form a compression chamber therebetween, and an annular seal member is disposed on the back of the orbiting scroll, and the seal member The inner high pressure region and the outer back pressure chamber are partitioned, and the orbiting scroll is brought into contact with the fixed scroll by applying a suction pressure or a constant intermediate pressure to the back pressure chamber, and a rotation restraining mechanism is provided on the back of the orbiting scroll. In the scroll compressor in which the orbiting scroll revolves along a circular path, and the compression chamber moves toward the center while changing the volume, and performs a series of operations of suction, compression, and discharge, the compression chamber starts from the high pressure region. A communication hole that leads to the end of the orbiting scroll is provided in the end plate of the orbiting scroll, and the communication hole is one of the compression chambers formed on both sides of the fixed scroll lap. It is those that face only. According to this configuration, oil can be supplied directly from the high pressure region on the back of the orbiting scroll to the compression chamber that is in a high temperature and high pressure state, and further to the top surface of the wrap of the fixed scroll where seizure is likely to occur. In addition, since oil is constantly supplied to the high pressure region, the amount of oil supplied to the compression chamber is also stable, and the influence of individual compressor differences due to assembly and component accuracy can be avoided. That is, it is possible to provide a scroll compressor that ensures high reliability.

  In the second aspect of the present invention, the closing position of the compression chamber is shifted by changing the spiral end angle of the orbiting scroll and the fixed scroll according to the first aspect, and the communication holes are formed on both sides of the fixed scroll lap. Of these compression chambers, only the high pressure side compression chamber is faced. According to this configuration, since the pressure difference between the high pressure region and the compression chamber becomes small, it is possible to reduce the amount of oil supplied to the compression chamber, and to suppress the viscosity loss that occurs between the wraps during compression. it can.

  In the present invention described in claim 3, in particular, the diameter of the communication hole described in claim 1 or 2 is formed within the range of 5% to 50% of the end plate thickness of the orbiting scroll. And according to this structure, oil quantity sufficient for lubrication can be supplied, suppressing viscosity loss.

In the present invention described in claim 4, the communication hole described in claim 3 is a multistage structure. And according to this structure, in the case of a large-sized compressor, since the thickness of the end plate increases, it is difficult to penetrate through the pores in processing. Therefore, by providing the communication hole with a multi-stage structure, it is possible to solve the processing problems and reduce the oil supply amount, and to supply a sufficient oil amount for lubrication while suppressing viscosity loss.

  In the present invention described in claim 5, oil holding means is provided on the upper surface of the wrap of the fixed scroll described in any one of claims 1 to 4. And according to this structure, since oil always exists between the wrap upper surface of the fixed scroll and the wrap bottom surface of the orbiting scroll, it becomes possible to prevent abnormal sliding and seizure.

  In the present invention as set forth in claim 6, the oil retaining means according to claim 5 is an opening having a predetermined section in the communication hole. And according to this structure, since the oil of an oil holding means changes continuously, lubrication becomes favorable and it becomes possible to prevent abnormal sliding and seizure.

  In the present invention described in claim 7, the oil retaining means described in claim 5 or 6 is an oil groove. According to this configuration, the upper surface of the fixed scroll can be lubricated over a wide range while being easy to process, so that abnormal sliding and seizure can be prevented.

  In the present invention according to claim 8, the groove width of the oil groove according to claim 7 is formed in the range of 25% to 80% of the wrap thickness of the fixed scroll. And according to this structure, since oil is hold | maintained at an oil groove and lubrication of the upper surface part of the lap | wrap of a fixed scroll becomes favorable, it becomes possible to prevent abnormal sliding and seizure.

  In the present invention described in claim 9, in particular, the depth of the oil groove according to claim 7 or 8 is formed within the range of 0.1% to 3% of the wrap thickness of the fixed scroll. And according to this structure, since oil is hold | maintained at an oil groove and lubrication of the upper surface part of the lap | wrap of a fixed scroll becomes favorable, it becomes possible to prevent abnormal sliding and seizure.

  In the present invention described in claim 10, dimples are formed on the upper surface of the wrap of the fixed scroll described in claim 5 or 6 in particular. And according to this structure, since oil can be hold | maintained at each recessed part, it can lubricate over the whole lap | wrap upper surface of a fixed scroll, and it becomes possible to prevent abnormal sliding and seizure.

  In the present invention described in claim 11, in particular, the diameter of the dimple according to claim 10 is made smaller than both the turning radius of the orbiting scroll and the wrap thickness of the fixed scroll, and the depth of the dimple is 20 μm or less. is there. And according to this structure, since oil is hold | maintained at a dimple and lubrication becomes favorable over the whole region of the upper surface part of a lap of a fixed scroll, it becomes possible to prevent abnormal sliding and seizure.

  According to the twelfth aspect of the present invention, in particular, in the scroll compressor according to any one of the first to eleventh aspects, the working fluid is a high-pressure refrigerant, for example, carbon dioxide. In this case, the difference between the high pressure and the low pressure is particularly large, and the load applied to the back of the orbiting scroll is also increased. Therefore, the effect of the present invention appears remarkably, and a scroll compressor ensuring high reliability can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
1 is a longitudinal sectional view of a scroll compressor according to the first embodiment of the present invention, FIG. 2 is an enlarged sectional view of a main part of the compression mechanism portion of FIG. 1, and FIG. 3 is a detailed sectional view of the compression mechanism portion. FIG. 4 is a plan view of the compression mechanism. Hereinafter, operation | movement and an effect | action are demonstrated about a scroll compressor.

  As shown in FIGS. 1 and 2, the scroll compressor of the present invention includes a main bearing member 11 of a crankshaft 4 fixed by welding or shrink fitting in a sealed container 1, and a bolt on the main bearing member 11. The scroll-type compression mechanism 2 is configured by sandwiching the orbiting scroll 13 that meshes with the fixed scroll 12 between the fixed scroll 12 and the rotation of the orbiting scroll 13 between the orbiting scroll 13 and the main bearing member 11. Then, an orbiting restraint mechanism 14 such as an Oldham ring that guides the circular scroll to move is provided, and the orbiting scroll 13 is eccentrically driven by the eccentric shaft portion 4a at the upper end of the crankshaft 4. As a result, the compression chamber 15 formed between the fixed scroll 12 and the orbiting scroll 13 moves from the outer peripheral side to the center portion. Utilizing this, the refrigerant gas is sucked and compressed from the suction pipe 16 leading to the outside of the sealed container 1 and the suction port 17 on the outer peripheral portion of the fixed scroll 12, and the refrigerant gas having a predetermined pressure or higher is compressed. The reed valve 19 is pushed open from the discharge port 18 at the center of the fixed scroll 12 and discharged into the sealed container 1 repeatedly.

  On the lap upper surface 13c of the orbiting scroll 13, based on the result of measuring the temperature distribution during operation, the height of the heel gradually increases from the winding start portion as the central portion to the winding end portion as the outer peripheral portion. Is provided with a slope shape. Thereby, the dimensional change by thermal expansion can be absorbed and local sliding can be prevented.

  Further, the orbiting scroll back surface 13e has an annular seal member 78 disposed on the main bearing member 11, and the seal member 78 performs an orbiting motion so that the high pressure region 30 that is the inner region of the seal member 78 and the outer region. And a back pressure chamber 29 set at a low pressure or an intermediate pressure. By applying pressure on the back surface 13e, the orbiting scroll 13 is stably pressed against the fixed scroll 12, and leakage can be reduced and the circular orbit motion can be stably performed.

  Further, the fixed scroll 12 is provided with a back pressure adjusting mechanism 9 for controlling the back pressure chamber 29 on the back surface 13e of the orbiting scroll 13 so as to always have a constant pressure.

  During operation of the compressor, a pump 25 is provided at the other downward end of the crankshaft 4 and is driven simultaneously with the scroll compressor. As a result, the pump 25 sucks up the oil 6 in the oil reservoir 20 provided at the bottom of the hermetic container 1 and supplies it to the compression mechanism 2 through the oil supply hole 26 extending vertically through the crankshaft 4. The supply pressure at this time is substantially equal to the discharge pressure of the scroll compressor, and also serves as a back pressure source for the orbiting scroll 13. As a result, the orbiting scroll 13 does not move away from the fixed scroll 12 and does not come into contact with each other, and the predetermined compression function is stably exhibited.

  A part of the oil 6 supplied in this way is obtained by a supply pressure or its own weight so as to obtain a clearance, between the fitting portion between the eccentric shaft portion 4a and the orbiting scroll 13, and between the crankshaft 4 and the main bearing member 11. Then, the oil enters the bearing portion 66, lubricates the respective portions, falls, and returns to the oil sump 20. Another part of the oil 6 supplied to the high-pressure region 30 passes through an oil supply passage 54 having an opening in the high-pressure region 30, is around the outer peripheral portion of the orbiting scroll 13, and the rotation restraint mechanism 14 is located. Along with entering the pressure chamber 29 and lubricating the thrust sliding portion and the sliding portion of the rotation restraining mechanism 14, the back pressure of the orbiting scroll 13 is applied in the back pressure chamber 29.

  The back pressure chamber 29 is sealed between the high pressure region 30 and the high pressure side by an annular sealing member 78, and the pressure increases as the incoming oil fills up. 9 acts to return and enter the suction portion of the compression chamber 15.

  The approach of the oil 6 is repeated at a predetermined cycle, and the timing of this repetition is determined by a combination of the relationship between the repeated cycle of suction, compression, and discharge and the pressure setting in the back pressure adjusting mechanism 9, Intentional lubrication of the sliding portion with the scroll 13 is achieved. This intentional lubrication is always ensured by the opening of the communication path 10 into the recess 10a by the back pressure adjusting mechanism 9 as described above. The oil 6 supplied to the suction port 17 moves to the compression chamber 15 along with the orbiting motion of the orbiting scroll 13 and serves to prevent leakage between the compression chambers 15.

  In the scroll compressor, the compression chamber 15 formed by meshing the swirls of the orbiting scroll 13 and the fixed scroll 12 progresses in compression from the outer peripheral side toward the central portion, and the working fluid becomes a high temperature and high pressure state. As a result, the orbiting scroll 13 and the fixed scroll 12 are also heated at the center, resulting in a dimensional change due to thermal expansion. In particular, this phenomenon appears remarkably under high-load operating conditions, and there is a possibility that seizure may occur due to the contact between the lap top surface 12c of the fixed scroll 12 and the lap bottom surface 13d of the orbiting scroll 13.

  As a method for preventing the above phenomenon, as shown in FIG. 3, in the scroll compressor according to the present embodiment, a communication hole 31 leading from the high pressure region 30 to the compression chamber 15 is provided in the end plate 13 a of the orbiting scroll 13. Only one of the compression chambers 15 formed on both sides of the wrap 12b of the fixed scroll 12 is exposed (15a or 15b). As a result, oil can be directly supplied from the high pressure region 30 to the compression chamber 15 in a high temperature and high pressure state, and further to the wrap upper surface 12c of the fixed scroll 12 where seizure is likely to occur. In addition, since the oil is always stably supplied to the high pressure region 30, the amount of oil supplied to the compression chamber 15 is also stable, and the influence of individual compressor differences due to assembly and component accuracy can be reduced. That is, it is possible to provide a scroll compressor that ensures high reliability.

  Further, as shown in FIG. 4, the closing positions of the two compression chambers 15 a and 15 b are shifted by changing the spiral end angles of the orbiting scroll 13 and the fixed scroll 12, and the communication holes 31 are formed on both sides of the wrap 12 b of the fixed scroll 12. Of the compression chambers 15a and 15b to be formed, only the compression chamber 15a on the high pressure side is exposed. As a result, the pressure difference between the high pressure region 30 and the compression chamber 15a is reduced, so that the amount of oil supplied to the compression chamber 15a can be reduced, and the viscosity loss that occurs between the wraps 12b and 13b during compression is suppressed. be able to.

(Embodiment 2)
5 and 6 are sectional views of the orbiting scroll according to the second embodiment of the present invention.

  If the amount of oil supplied from the high pressure region 30 to the compression chamber 15 is too small, abnormal sliding or seizure may occur. On the other hand, the greater the amount of oil, the better the lubrication and the better the sliding state of the lap top surface 12c of the fixed scroll 12 and the lap bottom surface 13d of the orbiting scroll 13 will be. However, since the inside of the compression chamber 15 becomes oil-rich, a large amount of oil inevitably intervenes between the wraps 12b and 13b of both scrolls, which causes an increase in viscosity loss. Therefore, as shown in FIG. 5, the diameter 31 d of the communication hole 31 may be formed within a range of 5% to 50% of the end plate thickness 13 t of the orbiting scroll 13. Accordingly, it is possible to supply a sufficient amount of oil for lubrication while suppressing viscosity loss.

  Alternatively, in the case of a large compressor, the thickness 13t of the end plate 13a of the orbiting scroll 13 is also large, so that it is difficult to penetrate through the fine holes in processing. Therefore, as shown in FIG. 6, the communication hole 31 has a multistage structure, thereby solving the processing problems and reducing the oil supply amount. With this configuration, it is possible to supply a sufficient amount of oil for lubrication while suppressing viscosity loss.

(Embodiment 3)
FIG. 7 is a plan view of a compression mechanism section according to the third embodiment of the present invention, and FIG. 8 is a detailed sectional view of the compression mechanism section. 7 and 8, the same components as those in FIGS. 4 and 3 are denoted by the same reference numerals, and description thereof is omitted.

  The oil supplied from the communication path 31 travels between the wrap upper surface 12c of the fixed scroll 12 and the compression chamber 15, but in order to improve the sliding of the wrap upper surface 12c of the fixed scroll 12 and the wrap bottom surface 13d of the orbiting scroll 13, It is necessary to provide oil retaining means on the wrap upper surface 12c of the fixed scroll 12. Thereby, oil always exists between the wrap upper surface 12c of the fixed scroll 12 and the wrap bottom surface 13d of the orbiting scroll 13, so that abnormal sliding and seizure can be prevented.

  In order to replace the oil interposed between the top surface 12c of the fixed scroll 12 and the bottom surface 13d of the orbiting scroll 13 and continue good lubrication, the oil retaining means may be opened in the communication hole 31 for a certain interval. As a result, the intervening oil is replaced, so that the temperature deterioration of the oil can be prevented, and abnormal sliding and seizure can be prevented.

  One proposal for a specific configuration of the oil retaining means is one in which an oil groove 32 is formed on the wrap upper surface 12c of the fixed scroll 12, as shown in FIG. Since the oil groove 32 can be easily processed, the lap upper surface 12c of the fixed scroll 12 can be lubricated over a wide range, and therefore, the sliding of the oil groove 32 with the lap bottom surface 13d of the orbiting scroll 13 can be realized.

  The groove width 32w and groove depth 32h of the oil groove 32 will be described in detail. When the groove width 32w and the groove depth 32h are small, the oil retention is insufficient, which may cause abnormal sliding or seizure. On the contrary, when the groove width 32w is large, the thickness of the wrap 12b left on both sides of the oil groove 32 becomes small, and oil easily leaks from the oil groove 32 to the compression chamber 15. Of oil will be supplied. Further, when the groove depth 32h is large, the pressure reducing effect in the oil groove 32 is lost, and therefore when the communication hole 31 faces the lap upper surface 12c of the fixed scroll 12, a large amount is supplied to the compression chamber 15b on the low pressure side. Oil will be supplied. When a large amount of oil is supplied, a large amount of oil is interposed between the wraps 12b and 13b of both scrolls, causing an increase in viscosity loss. Therefore, as shown in FIG. 8, the groove width 32w of the oil groove 32 is preferably formed in the range of 25% to 80% of the wrap thickness 12t of the fixed scroll 12, and the groove depth 32h is the wrap thickness of the fixed scroll 12. It is desirable to form within the range of 0.1% to 3% of 12t. This makes it possible to maintain a sufficient amount of oil for lubrication while suppressing viscosity loss.

(Embodiment 4)
9A is a plan view of a compression mechanism section according to the fourth embodiment of the present invention, FIG. 9B is an enlarged plan view of the main part, and FIG. 9C is an enlarged sectional view of the main part. is there. In FIG. 9, the same components as those in FIG.

  As another plan of the specific configuration of the oil retaining means, there is a method of forming dimples 33 on the wrap upper surface 12c of the fixed scroll 12, as shown in FIG. Thereby, since oil can be held in the individual recesses, it can be lubricated over the entire area of the wrap upper surface 12c of the fixed scroll 12, and abnormal sliding and seizure can be prevented. In the present embodiment, the dimple 33 is formed on the wrap upper surface 12 c of the fixed scroll 12, but the dimple 33 may be formed in the entire region corresponding to the turning range of the orbiting scroll 13.

The dimensions of the dimple 33 will be described in detail. The diameter of the dimple 33 needs to be smaller than both the turning radius 13r of the orbiting scroll 13 and the wrap thickness 12t of the fixed scroll 12. Since the diameter of the dimple 33 is smaller than the turning radius 13r, the oil held in the dimple 33 is discharged from the dimple 33 along with the turning motion, and simultaneously enters the dimple 33. That is, the oil held in the dimple 33 is replaced, and the lap upper surface 12c of the fixed scroll 12 is lubricated. Moreover, since the diameter of the dimple 33 is smaller than the wrap thickness 12t, leakage between the compression chambers 15 can be prevented. The depth of the dimple 33 is preferably 20 μm or less, and the oil is sufficiently held by the dimple 33. More desirably, the depth is set to 5 μm or less, and dynamic pressure is generated by the turning motion and the effect of reducing the pressing force due to the back pressure is generated. Therefore, in addition to good lubrication, input reduction can be realized. .

  Finally, when the working fluid is a high-pressure refrigerant, such as carbon dioxide, the difference between the high and low pressures is particularly large, and the load applied to the orbiting scroll back surface 13e is also increased. It is possible to provide a scroll compressor that can ensure high performance.

  As described above, the scroll compressor according to the present invention stably supplies oil to the compression chamber that is in a high-temperature and high-pressure state, thereby seizing the upper surface portion of the fixed scroll and the end plate portion of the orbiting scroll. Therefore, the working fluid is not limited to the refrigerant, and can be applied to scroll fluid machines such as an air scroll compressor, a vacuum pump, and a scroll type expander.

Sectional drawing of the scroll compressor in Embodiment 1 of this invention The principal part expanded sectional view of the compression mechanism part of the scroll compressor in Embodiment 1 of this invention Detailed sectional drawing of the compression mechanism part of the scroll compressor in Embodiment 1 of this invention The top view of the compression mechanism part of the scroll compressor in Embodiment 1 of this invention Sectional drawing of the turning scroll of the scroll compressor in Embodiment 2 of this invention Sectional drawing of the turning scroll of the scroll compressor in Embodiment 2 of this invention The top view of the compression mechanism part of the scroll compressor in Embodiment 3 of this invention Detailed sectional drawing of the compression mechanism part of the scroll compressor in Embodiment 3 of this invention The top view of the compression mechanism part of the scroll compressor in Embodiment 4 of this invention, an enlarged plan view, an expanded sectional view Sectional view of a conventional scroll compressor

Explanation of symbols

12 fixed scroll 12b wrap 12t wrap thickness 13 orbiting scroll 13a end plate 13b wrap 13t end plate thickness 14 rotation restraint mechanism 15 compression chamber 15a compression chamber on the high pressure side 29 back pressure chamber 30 high pressure region 31 communication hole 31d diameter of communication hole 32 oil groove 32h Groove depth 32w Groove width 33 Dimple 78 Seal member

Claims (12)

A compression scroll is formed between the fixed scroll and the orbiting scroll where the spiral wrap rises from the end plate, and an annular seal member is disposed on the back of the orbiting scroll. The orbiting scroll is divided into a back pressure chamber, and the orbiting scroll is brought into contact with the fixed scroll by applying a suction pressure or a fixed intermediate pressure to the back pressure chamber, and a rotation restraining mechanism is provided on the back of the orbiting scroll. In the scroll compressor in which the scroll is swung along a circular trajectory, and the compression chamber moves toward the center while changing the volume, and performs a series of operations of suction, compression, and discharge.
A scroll compressor in which a communication hole leading from the high pressure region to the compression chamber is provided in the end plate of the orbiting scroll, and the communication hole faces only one of the compression chambers formed on both sides of the wrap of the fixed scroll. . The closed position of the compression chamber is shifted by changing the spiral end angle of the orbiting scroll and the fixed scroll, and the communication hole faces only the compression chamber on the high pressure side among the compression chambers formed on both sides of the wrap of the fixed scroll. Item 2. The scroll compressor according to Item 1. The scroll compressor according to claim 1 or 2, wherein a diameter of the communication hole is formed within a range of 5% to 50% of a thickness of the end plate of the orbiting scroll. The scroll compressor according to claim 3, wherein the communication hole has a multistage structure. The scroll compressor according to any one of claims 1 to 4, further comprising oil holding means on a top surface of the wrap of the fixed scroll. The scroll compressor according to claim 5, wherein the oil retaining means is formed by opening a predetermined section in the communication hole. The scroll compressor according to claim 5 or 6, wherein the oil retaining means is an oil groove. The scroll compressor according to claim 7, wherein the groove width of the oil groove is formed within a range of 25% to 80% of the wrap thickness of the fixed scroll. The scroll compressor according to claim 7 or 8, wherein the depth of the oil groove is formed within a range of 0.1% to 3% of the wrap thickness of the fixed scroll. The scroll compressor according to claim 5 or 6, wherein the oil retaining means is a dimple. The scroll compressor according to claim 10, wherein the dimple diameter is smaller than both the turning radius of the orbiting scroll and the wrap thickness of the fixed scroll, and the depth of the dimple is 20 µm or less. The scroll compressor according to any one of claims 1 to 11, wherein the working fluid is a high-pressure refrigerant, for example, carbon dioxide.