JP2011202527A - Rotary compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high performance and highly-reliable rotary compressor properly reducing a thrust load acting on a cylinder with a simple structure.SOLUTION: The rotary compressor includes a piston 11 driven by a shaft 8, the cylinder 12 arranged eccentrically to the piston 11 and having a hollow inner cylindrical face and an end plate 12A at one end, and vanes slidably inserted in vane grooves formed in the outer periphery of the piston 11 and having ends contacting with the inner cylindrical face of the cylinder 12 to form a compression chamber 13, and the cylinder 12 and the piston 11 rotate synchronously in the same direction. A back pressure chamber 18 airtightly divided from a surrounding space is provided between the backside of the end plate 12A and a frame 16, and a bleed hole 19 communicating with the compression chamber 13 is provided in the end plate 12A, so that the bleed hole 19 communicates with the back pressure chamber 18 only in a certain section of one rotation of the cylinder 12 and gas in the middle of compression is supplied into the back pressure chamber 18.

Description

  The present invention relates to a rotary compressor that compresses and pressurizes a fluid, such as an air conditioner and a heat pump type hot water heater.

  Conventionally, a cylinder having a cylindrical hollow portion in a housing, a cylindrical piston that is arranged eccentrically with respect to the cylinder in the hollow portion, and is integrally attached to a shaft that transmits a rotational force from a driving source, and a piston In a fluid machine provided with a vane that is slidably mounted in a vane groove provided on the outer periphery of the cylinder and whose tip is in sliding contact with the inner cylindrical surface of the cylinder to form a compression chamber, the cylinder is rotatably supported. A double-rotating sliding vane compressor configured to rotate in the same direction as a piston is known (see, for example, Patent Document 1).

  Another double-rotation type sliding vane compressor has a structure in which an end plate is provided at one end of an axial end of a cylinder in addition to the same configuration as described above (see, for example, Patent Document 2). In this type of structure in which the end plate is provided on the cylinder, different pressures act on the compression side surface and the opposite side surface of the end plate, so that a thrust load is generated in the cylinder in the axial direction. Therefore, in Patent Document 2, an intermediate pressure chamber maintained at a pressure (intermediate pressure) between the suction pressure of the gas sucked into the cylinder and the discharge pressure of the gas compressed in the cylinder is defined as the cylinder outer space. And a pressure adjusting mechanism using a spring is provided between the intermediate pressure chamber and the suction pressure space or the discharge pressure space to adjust the pressure in the intermediate pressure chamber to an appropriate pressure. As a result, the thrust load acting on the cylinder is reduced, and friction loss and wear caused by pressing the cylinder in one direction are reduced.

  Further, in Patent Document 1, since the cylinder does not have an end plate, a thrust load is not generated in the cylinder, but friction and wear due to contact between both end surfaces of the cylinder and the side housing that houses the cylinder occurs. For this reason, an example is shown in which an air film is formed by supplying high-pressure air to both ends of the cylinder to reduce friction and wear.

JP 59-188083 A (2nd page, lower right column to 5th page, lower right column, FIGS. 1 and 2) JP 2000-9069 A ([0016] to [0019], [0031], [0032])

  However, the air film disclosed in Patent Document 1 has a small load capacity. For this reason, it is possible to avoid contact when there is no end plate in the cylinder and the thrust load does not basically act, but rotation of a structure having an end plate at one end of the cylinder as shown in Patent Document 2 Since a large thrust load acts on the compressor, it is difficult to avoid contact with an air film.

  Moreover, in patent document 2, in order to maintain an intermediate pressure chamber at an appropriate intermediate pressure, a pressure adjustment mechanism is required, and thus the number of components such as valves and springs increases.

  The present invention has been made to solve the above-described problems, and can reduce the thrust load acting on the cylinder appropriately with a simple structure without requiring a pressure adjustment mechanism using a spring. The purpose is to obtain a high-performance and highly reliable rotary compressor.

  The rotary compressor according to the present invention is provided with a sealed container in which the pressure in the sealed container is maintained at a discharge pressure except for a part thereof, a fixed in the sealed container, and a suction port and a discharge port. Housing, a shaft rotatably supported with respect to the housing and driven by driving means, a frame fixed to the housing and rotatably supporting the shaft, and a circle fixed to the shaft and rotating integrally with the shaft A frame having a columnar piston, a cylindrical portion that accommodates the piston in an eccentric state, and an end plate that closes an opening at one end of the cylindrical portion, and is fixed to a housing that closes the opening at the other end of the cylindrical portion A cylinder that is rotatably supported and rotates synchronously in the same direction as the piston, a means for rotating the piston and the cylinder synchronously, and slides in at least one vane groove provided on the outer periphery of the piston And at least one vane that forms a compression chamber in the space in the cylinder by sliding the tip in sliding contact with the inner cylinder surface of the cylinder, and between the back surface of the end plate of the cylinder and the frame. In addition to providing a back pressure chamber that is hermetically partitioned from the surrounding space, the cylinder end plate is provided with a bleed hole that penetrates the compression chamber, and the bleed hole is provided only in a certain section during one rotation of the cylinder. The gas in the middle of compression is communicated with the gas and is supplied to the back pressure chamber.

  According to the present invention, in the double-rotation type sliding vane compressor in which the piston and the cylinder rotate synchronously, the back pressure chamber that is airtightly partitioned from the surrounding space between the back surface of the end plate of the cylinder and the frame. Since the gas in the middle of compression is supplied into the back pressure chamber and the pressure in the back pressure chamber is set to the intermediate pressure between the suction pressure and the discharge pressure, the thrust load acting on the cylinder can be reduced and the friction loss can be reduced. A low-performance rotary compressor can be obtained.

It is a longitudinal cross-sectional view which shows the rotary compressor by Embodiment 1 of this invention. It is sectional drawing along the AA line of FIG. It is sectional drawing along the BB line of FIG. It is sectional drawing along the CC line of FIG. FIG. 3 is a cross-sectional view at a position advanced by a certain rotation angle from the position of FIG. 2. FIG. 5 is a cross-sectional view at a position advanced by a certain rotation angle from the position of FIG. 4. It is a schematic diagram which shows the thrust load which acts on a cylinder in the rotary compressor by Embodiment 1 of this invention. It is sectional drawing corresponding to FIG. 3 which shows another Example of the rotary compressor by Embodiment 1 of this invention. It is a longitudinal cross-sectional view which shows the rotary compressor by Embodiment 2 of this invention. It is a schematic diagram which shows the thrust load which acts on a cylinder in the rotary compressor by Embodiment 2 of this invention.

Embodiment 1 FIG.
1 is a longitudinal sectional view showing a rotary compressor according to Embodiment 1 of the present invention. 2 is a cross-sectional view taken along line AA in FIG. 1, FIG. 3 is a cross-sectional view taken along line BB in FIG. 1, and FIG. 4 is taken along line CC in FIG. FIG. In this example, the refrigerant (gas) of the refrigeration air conditioner is compressed by the rotary compressor. The rotary compressor shown in FIGS. 1 to 4 is a double-rotating type sliding vane compressor, in which a motor 2 is disposed above a vertical sealed container 1 and a compression mechanism 3 is disposed below the motor 2. It is installed. An oil sump 4 for storing oil is formed further below the compression mechanism 3. A suction pipe 5 for sucking gas is provided on the side surface of the sealed container 1, and a discharge pipe 6 for discharging compressed gas is provided on the upper surface of the sealed container 1. Further, a glass terminal 7 for supplying electric power is provided at the upper end of the sealed container 1.

  The motor 2 includes a stator 41 formed in a ring shape, and a rotor 42 supported so as to be able to rotate inside the stator 41. Further, the shaft 8 is fixed to the rotor 42, penetrates the compression mechanism 3, and its lower end is immersed in the oil in the oil sump 4. At the lower end of the shaft 8, a centrifugal pump type oil pump mechanism 9 described in, for example, JP-A-60-206988 is formed. The centrifugal pump type oil pump mechanism 9 includes a first oil supply passage 8a provided eccentric to the shaft 8, and a cup 10 attached to the lower end of the shaft 8 and having a suction port 10a at the center. The oil stored in the oil sump 4 is sucked upward by the centrifugal force of the shaft 8.

  The compression mechanism 3 includes a piston 11, a cylinder 12, a first vane 14 a, a second vane 14 b, a housing 15, and a frame 16. The piston 11 is integrally formed with the shaft 8 and is formed in a columnar shape with vane grooves 11a and 11b provided in the radial direction. The cylinder 12 has a hollow cylindrical portion 12a that accommodates the piston 11 and an end plate 12A that closes an opening at the lower end of the cylindrical portion 12a, and is arranged eccentrically with respect to the cylindrical piston 11. ing. In addition, the tip of the first vane 14a is accommodated in one place on the inner surface (inner cylinder surface) of the cylindrical portion 12a of the cylinder 12, and the arc-shaped groove 12b for rotating the piston 11 and the cylinder 12 in synchronization with each other. Is provided. The first vane 14a and the second vane 14b are slidably fitted into the vane grooves 11a and 11b, and the tip of the first vane 14a is in an arc-shaped groove 12b provided on the inner cylinder surface of the cylinder 12. The tip of the second vane 14 b is slidably pressed against the inner cylinder surface of the cylinder 12 to form a compression chamber 13.

  The housing 15 is fixed to the hermetic container 1 and is disposed close to the upper end surface of the piston 11 and the upper end surface of the cylinder 12, and closes the upper end opening of the cylindrical portion 12 a of the cylinder 12. In the housing 15, an upper bearing 15 a that supports the shaft 8, a suction port 15 b that is connected to the suction pipe 5 and sends gas to the compression chamber 13, and a gas discharged from the compression chamber 13 is disposed above the compression mechanism 3. A discharge port 15c for guiding is provided.

  The frame 16 has a hollow portion 16a and a disk portion 16A that closes the lower end opening of the hollow portion 16a and is formed in a substantially bottomed cylindrical shape. The cylinder 16 and the piston 11 are accommodated in the hollow portion 16a, The upper end (open end) of the hollow portion 16 a is fixedly attached to the housing 15. Further, in the central portion of the disk portion 16A of the frame 16, a lower bearing 16b that supports the shaft 8 together with the upper bearing 15a, and a cylinder bearing 16c that is disposed outside the lower bearing 16b and supports the end plate 12A of the cylinder 12. And the shaft 8 is rotatably supported.

  An annular recess for forming a back pressure chamber 18 between the end plate 12 </ b> A of the cylinder 12 is formed in the disc portion 16 </ b> A of the frame 16. A part of the inner side surface of the back pressure chamber 18 is provided with a rectangular columnar cut portion 18 a extending in the depth direction of the back pressure chamber 18. A seal mechanism 17a is provided on the inner diameter side of the back pressure chamber 18, and a seal mechanism 17b is provided on the outer diameter side. The back pressure chamber 18 is airtightly partitioned from the surrounding space held by the discharge pressure. Further, the end plate 12A of the cylinder 12 is provided with a bleed hole 19 whose one end opens into the compression chamber 13, and when the piston 11 and the cylinder 12 are in the position of FIG. As shown in FIG. 4, it communicates with the cut portion 18 a of the back pressure chamber 18.

  The hollow portion 16 a of the frame 16 is provided with a communication path 16 d for communicating the inner space and the outer space of the frame 16. On the outer peripheral side of the housing 15, the outer space of the frame 16 and the upper space of the housing 15 are provided. A communication path 15d is provided for communicating the. Hereinafter, the outer space of the frame 16 is referred to as a first space 30, and the space between the frame 16 and the cylinder 12 (excluding the back pressure chamber 18) is referred to as a second space 31.

  Further, the discharge port 15c is formed through the housing 15 in the axial direction of the shaft 8, and a discharge valve 20 is attached to an intermediate portion of the through hole. Further, the upper bearing 15a and the lower bearing 16b and the first oil supply passage 8a provided in the shaft 8 communicate with each other, and a part of the oil supplied to the lower bearing 16b is supplied to the frame 16 to the cylinder bearing 16c. For this purpose, a second oil supply passage 16e is provided. Further, an oil return hole 16 f for discharging the oil accumulated in the second space 31 to the oil sump 4 is provided in the disc portion 16 </ b> A of the frame 16.

Hereinafter, the operation of the rotary compressor according to the first embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, 4, 5, and 6. 5 shows a cross-sectional view at a position advanced by a certain rotation angle from the position of FIG. 2, and FIG. 6 shows a cross-sectional view at a position advanced by the same rotation angle from the position of FIG. The arrows in FIG. 5 indicate the rotation direction.
When power is supplied to the glass terminal 7, a driving force is generated in the motor 2 including the rotor 42 and the stator 41, the shaft 8 is driven, and the piston 11 attached integrally with the shaft 8 is also centered on the shaft 8 (see FIG. Rotate around 2 point C1. When the piston 11 rotates, the first vane 14a rotates around the shaft 8 together with the piston 11 while moving in and out of the vane groove 11a by centrifugal force and back pressure. On the other hand, the second vane 14b rotates around the shaft 8 together with the piston 11 while moving in and out of the vane groove 11b by centrifugal force and back pressure, and the tip of the second vane 14b slides on the inner cylinder surface of the cylinder 12. Touch.

  The distal end portion of the first vane 14a presses the arc-shaped groove 12b in the tangential direction of the arc as the first vane 14a rotates. Since the cylinder 12 is rotatably supported by a cylinder bearing 16c provided on the frame 16, the tip of the first vane 14a presses the arc-shaped groove 12b in the tangential direction, so that the cylinder 12 It rotates synchronously with the piston 11 around the point C2 in FIG. With the above operation, the volume in the compression chamber 13 is increased or decreased.

  The gas taken into the compression chamber 13 from the outside of the compressor via the suction pipe 5 and the suction port 15b is compressed in the compression chamber 13, and then is moved upward of the housing 15 via the discharge port 15c and the discharge valve 20. Is discharged from the discharge pipe 6 to the outside of the compressor. The arrows in FIG. 1 indicate the gas flow. As described above, the upper space of the housing 15 becomes the discharge pressure. Further, since the upper space of the housing 15 communicates with the first space 30 and the second space 31 through the communication passage 15d and the communication passage 16d, the first space 30 and the second space 31 also serve as discharge pressure. In the first embodiment, since two vanes 14a and 14b are provided, suction and discharge are performed twice per rotation.

  On the other hand, as the shaft 8 rotates, the oil in the oil sump 4 is sucked upward from the suction port 10a provided in the center of the cup 10 by the pump action of the oil pump mechanism 9, and then the first oil supply path 8a is passed through. The oil is supplied to the lower bearing 16b and the upper bearing 15a. A part of the oil supplied to the lower bearing 16 b is supplied to the cylinder bearing 16 c through the second oil supply passage 16 e provided in the frame 16.

  Further, since the second space 31 outside the cylinder 12 is at a discharge pressure, gas hardly leaks from the compression chamber 13 side to the second space 31 side through the upper end surface of the cylinder 12, but the centrifugal force due to the rotation of the cylinder 12 For example, gas may leak from the compression chamber 13 side to the second space 31. At this time, oil contained in the gas in the compression chamber 13 also leaks into the second space 31 and accumulates at the bottom of the frame 16, but is returned to the oil sump 4 through an oil return hole 16 f provided at the bottom of the frame 16. .

  2 and 4, the compression chamber 13 and the back pressure chamber 18 communicate with each other through the extraction hole 19 and the cut portion 18a of the back pressure chamber 18, and the gas in the compression chamber 13 is being compressed. It is supplied to the back pressure chamber 18. Since the gas being compressed is an intermediate pressure between the suction pressure and the discharge pressure, the pressure in the back pressure chamber 18 is an intermediate pressure. Next, when the cylinder 12 reaches the position of FIG. 5 that is advanced by a certain rotation angle from the position of FIG. 2, the bleed hole 19 indicated by the broken line is sealed by the disc portion 16A of the frame 16 as shown in FIG. Gas supply to the pressure chamber 18 is stopped. Therefore, the back pressure chamber 18 communicates with the compression chamber 13 via the bleed hole 19 and the cut portion 18a of the back pressure chamber 18 only in a certain section during one rotation.

  In the compression chamber 13, the gas pressure changes from the suction pressure to the discharge pressure. For this reason, the pressure of the back pressure chamber 18 can be changed depending on at which stage of the pressure change the compression chamber 13 communicates with the back pressure chamber 18. Therefore, the arrangement positions of the extraction holes 19 and the cut portions 18 a are determined so that the compression chamber 13 communicates with the back pressure chamber 18 when the compression chamber 13 reaches a desired intermediate pressure with respect to the back pressure chamber 18. Since the back pressure chamber 18 is hermetically partitioned from the space other than the back pressure chamber 18 by the sealing mechanisms 17a and 17b, the back pressure chamber 18 is always maintained at an intermediate pressure.

  Here, the load acting on the cylinder 12 will be described with reference to FIG. FIG. 7A shows a case where the back pressure chamber 18 is not provided, and FIG. 7B shows a case where the back pressure chamber 18 is provided. In FIG. 7A, a downward thrust load Fa acts on the surface of the end plate 12 </ b> A of the cylinder 12 on the compression chamber 13 side (hereinafter referred to as the compression chamber side surface) due to the pressure generated in the compression chamber 13. On the other hand, since the discharge pressure Pd acts on the entire surface of the end plate 12A of the cylinder 12 opposite to the side surface of the compression chamber (hereinafter referred to as the back surface), an upward thrust load Fb larger than the thrust load Fa is applied to the end plate. Acts on the back of 12A. Therefore, the cylinder 12 is pressed against the housing 15 with the upward thrust load Ft given by the equation (1).

          Ft = Fb−Fa (1)

  In contrast, in the rotary compressor according to the first embodiment of the present invention, as shown in FIG. 7B, the back pressure chamber 18 is maintained at the intermediate pressure Pm, which is the pressure during compression, as described above. Has been. Therefore, the upward thrust load acting on the back surface of the end plate 12A of the cylinder 12 is smaller than Fb. Assuming that the area where the intermediate pressure Pm acts on the back surface of the end plate 12A of the cylinder 12 is A and the upward thrust load acting on the back surface of the end plate 12A of the cylinder 12 is Fb1, the thrust load Fb1 is given by equation (2). It is done.

          Fb1 = Fb− (Pd−Pm) × A (2)

  As a result, the upward thrust load Ft generated in the cylinder 12 becomes smaller than Fb1 as shown in the equation (3).

          Ft = Fb1-Fa (3)

  As is clear from the above equation (2), Fb1 can be reduced by increasing the area A by changing the positions of the inner and outer diameters of the back pressure chamber 18, for example. Therefore, depending on the setting of the size of the back pressure chamber 18, the upward thrust load Ft acting on the cylinder 12, that is, the pressing force of the cylinder 12 against the housing 15 can be extremely small or canceled. Note that the thrust load Fb1 may be slightly smaller than the thrust load Fa, and a small downward thrust load Ft may be applied to the cylinder 12 so that the cylinder 12 is pressed against the frame 16 with a light force.

  Also, the thrust load Ft can be made extremely small or canceled by changing the magnitude of the intermediate pressure Pm. Since the intermediate pressure Pm is related to the arrangement position of the bleed hole 19 and the cut portion 18a as described above, by changing the position of the cut portion 18a of the back pressure chamber 18 provided in the disc portion 16A of the frame 16, The magnitude of the intermediate pressure Pm can be changed. For example, in FIG. 6, the back pressure chamber 18 has a position advanced in the rotational direction by providing a cut portion 18 a of the back pressure chamber 18 at the position of the bleed hole 19 indicated by a broken line hidden in the disk portion 16 </ b> A of the frame 16. An intermediate pressure at is introduced. Since the gas is compressed and the pressure increases as it advances in the direction of rotation, a higher intermediate pressure is introduced into the back pressure chamber 18 than when the cut portion 18a of the back pressure chamber 18 is provided at the position of FIG. Can do. Further, if the cut portion 18a of the back pressure chamber 18 is provided in a direction opposite to the rotation direction (upward in the drawing) from the position shown in FIG. 4, the cut portion 18a of the back pressure chamber 18 is provided at the position of FIG. Compared to the case, a lower intermediate pressure can be introduced into the back pressure chamber 18.

  As described above, a wide range of intermediate pressures can be guided to the back pressure chamber 18 simply by changing the position of the cut portion 18 a of the back pressure chamber 18.

  Also, the size of the intermediate pressure Pm can be changed by changing the position of the extraction hole 19. During the rotation of the piston 11 and the cylinder 12, the positional relationship between the first vane 14a and the extraction hole 19 does not change. Therefore, for example, when the bleed hole 19 is brought closer to the first vane 14a with the position of FIG. 2 as a reference, the back pressure chamber 18 is rotated in the direction of rotation more than when the bleed hole 19 is provided at the position of FIG. The intermediate pressure at the position advanced to is introduced. Naturally, conversely, if the position of the bleed hole 19 is provided in a direction away from the first vane 14a than the position shown in FIG. 2, the bleed hole 19 is located at the position of FIG. The intermediate pressure at a position delayed in the rotational direction is introduced as compared with the case where is provided. As described above, even if the position of the bleed hole 19 is changed, a wide range of intermediate pressures can be guided to the back pressure chamber 18.

  As described above, the rotary compressor according to the first embodiment of the present invention is a double-rotating type in which the pressure in the hermetic container 1 is maintained at the discharge pressure except for a part, and the piston and the cylinder rotate synchronously. In this sliding vane compressor, a back pressure chamber 18 is provided in the frame 16 on the back side of the end plate 12A of the cylinder 12, and an intermediate pressure, which is a gas being compressed, is introduced into the back pressure chamber 18. Thereby, the thrust load Ft acting on the cylinder 12 can be greatly reduced or canceled. For this reason, the friction loss which generate | occur | produces by sliding with the cylinder 12 and the housing 15 or sliding with the cylinder 12 and the flame | frame 16 can be reduced significantly. Therefore, it is possible to obtain a high-performance rotary compressor with a simple structure and a small friction loss without requiring a pressure adjusting mechanism using a spring. Further, since friction loss can be reduced, energy saving can be achieved.

  Further, since the oil leaked into the second space 31 outside the cylinder 12 can be surely returned to the oil sump 4 from the oil return hole 16f, a highly reliable rotary compressor without fear of oil exhaustion is provided. It becomes possible.

  Further, it is possible to guide a wide range of intermediate pressures to the back pressure chamber 18 by adjusting the positional relationship between the bleed hole 19 and the cut portion 18a.

  FIG. 8 shows another example of the rotary compressor according to the first embodiment of the present invention. FIG. 8 is a cross-sectional view corresponding to FIG. In the embodiment of FIG. 8, the notch 18a of the back pressure chamber 18 is provided on the outer side surface of the annular portion. In this case, naturally, the bleed hole 19 is provided at a position communicating with the cut portion 18a of the back pressure chamber 18 at a certain rotational position (not shown). Also in this embodiment, the operation is the same as described above, and an intermediate pressure can be introduced into the back pressure chamber 18.

Embodiment 2. FIG.
FIG. 9 is a longitudinal sectional view showing a rotary compressor according to Embodiment 2 of the present invention. In FIG. 9, the same parts as those in the first embodiment shown in FIG. In the following, the second embodiment will be described focusing on the differences from the first embodiment.

  In the rotary compressor of the first embodiment, the suction pipe 5 is connected to the side surface of the hermetic container 1, the discharge pipe 6 is connected to the upper surface of the hermetic container 1, and the inside of the hermetic container 1 includes a part of the compression chamber 13 and the like. It was a type of rotary compressor that was maintained at the discharge pressure except for the above. On the other hand, in the rotary compressor of the third embodiment, the suction pipe 5 is connected to the upper surface of the sealed container 1, the discharge pipe 6 is connected to the side surface of the sealed container 1, and the inside of the sealed container 1 is the compression chamber 13 or the like. The rotary compressor is a type that is maintained at the suction pressure except for a part of the compressor, and the configuration of the main part of the compression mechanism 3 is substantially the same as that of the first embodiment.

  In FIG. 9, a suction pipe 5 for sucking gas is provided on the upper surface of the sealed container 1, and a discharge pipe 6 for discharging compressed gas is provided on the side surface of the sealed container 1. The housing 15 is provided with a suction port 15 b for sending gas from above the compression mechanism 3 to the compression chamber 13 and a discharge port 15 c for sending gas discharged from the compression chamber 13 connected to the discharge pipe 6. ing. The discharge port 15c has a through hole 15ca formed through the housing 15 in the axial direction of the shaft 8, and a through hole 15cb having one end communicating with the through hole 15ca and the other end communicating with the discharge pipe 6. Yes. A discharge valve 20 is attached to an intermediate portion of the through hole 15ca, and a lid 21 for sealing the discharge port 15c with the upper space of the housing 15 is provided at the upper end portion of the through hole 15ca.

  The operation of the rotary compressor according to the second embodiment of the present invention will be described below with reference to FIG. The gas taken into the sealed container 1 from the outside of the compressor via the suction pipe 5 is taken into the compression chamber 13 from a suction port 15 b provided in the housing 15. The gas taken into the compression chamber 13 is compressed in the compression chamber 13 and then discharged from the discharge pipe 6 to the outside of the compressor through the through hole 15ca, the discharge valve 20 and the through hole 15cb of the discharge port 15c. . The arrows in FIG. 9 indicate the gas flow. As a result, the upper space of the housing 15 becomes the suction pressure. Further, since the upper space of the housing 15 communicates with the first space 30 and the second space 31 through the communication passage 15d and the communication passage 16d, the first space 30 and the second space 31 also serve as suction pressure.

  Here, the load acting on the cylinder 12 will be described with reference to FIG. FIG. 10A shows a case where the back pressure chamber 18 is not provided, and FIG. 10B shows a case where the back pressure chamber 18 is provided. In FIG. 10A, a downward thrust load Fa acts on the compression chamber side surface (hereinafter referred to as the compression chamber side surface) of the end plate 12 </ b> A of the cylinder 12 due to the pressure generated in the compression chamber 13. On the other hand, since suction pressure Ps acts on the entire surface of the end plate 12A of the cylinder 12 opposite to the side of the compression chamber (hereinafter referred to as the back surface), the thrust load that pushes the cylinder 12 upward from the back surface of the end plate 12A is Does not occur. For this reason, the cylinder 12 is pressed against the frame 16 with the downward thrust load Ft given by the equation (4).

          Ft = Fa (4)

  On the other hand, when the back pressure chamber 18 is provided, the back pressure chamber 18 is maintained at the intermediate pressure Pm as shown in FIG. Assuming that the area where the intermediate pressure Pm acts on the back surface of the end plate 12A of the cylinder 12 is A, an upward thrust load Fc shown in Expression (5) acts on the end plate 12A.

          Fc = (Pm−Ps) × A (5)

  Then, the downward thrust load Ft generated in the cylinder 12 becomes smaller than Fa as shown in the equation (6).

          Ft = Fa−Fc (6)

  As is clear from the above equations (5) and (6), Ft can be reduced by increasing the area A by changing the positions of the inner and outer diameters of the back pressure chamber 18. Therefore, depending on the setting of the size of the back pressure chamber 18, the upward thrust load Ft acting on the cylinder 12 can be made extremely small or canceled. Note that the thrust load Fc may be slightly larger than the downward thrust load Fa, and a small upward thrust load Ft may be applied to the cylinder 12 so that the cylinder 12 is pressed against the housing 15 with a light force.

  Also, the thrust load Ft can be made extremely small or canceled by changing the magnitude of the intermediate pressure Pm. The magnitude of the intermediate pressure Pm is changed by changing the position of the cut portion 18a of the back pressure chamber 18 provided in the disc portion 16A of the frame 16 as described in the first embodiment, or It can be changed by changing the position.

  As described above, the rotary compressor according to the second embodiment of the present invention is a double-rotating type in which the pressure in the sealed container 1 is maintained at the suction pressure except for a part, and the piston and the cylinder rotate synchronously. In this sliding vane compressor, a back pressure chamber 18 is provided in the frame 16 on the back side of the end plate 12A of the cylinder 12, and an intermediate pressure, which is a gas being compressed, is introduced into the back pressure chamber 18. Thereby, the thrust load Ft acting on the cylinder 12 can be greatly reduced or canceled. For this reason, the friction loss which generate | occur | produces by sliding with the cylinder 12 and the housing 15 or sliding with the cylinder 12 and the flame | frame 16 can be reduced significantly. Therefore, it is possible to obtain a high-performance rotary compressor with a simple structure and a small friction loss without requiring a pressure adjusting mechanism using a spring. Further, since friction loss can be reduced, energy saving can be achieved.

  Further, since the oil leaked into the second space 31 outside the cylinder 12 can be surely returned to the oil sump 4 from the oil return hole 16f, a highly reliable rotary compressor without fear of oil exhaustion is provided. It becomes possible.

  Further, it is possible to guide a wide range of intermediate pressures to the back pressure chamber 18 by adjusting the positional relationship between the bleed hole 19 and the cut portion 18a.

  In the rotary compressor according to the first and second embodiments of the present invention, the arc-shaped groove 12b is provided at one place on the inner cylindrical surface of the cylinder 12 as means for rotating the piston 11 and the cylinder 12 in synchronization. And the piston 11 and the cylinder 12 are rotated synchronously by pressing the tip of the first vane 14a against the arcuate groove 12b. As another means for rotating the piston 11 and the cylinder 12 in synchronism, for example, an Oldham joint disclosed in Japanese Patent Application Laid-Open No. 2000-161270 may be used to rotate the piston and the cylinder in synchronism. In the rotary compressors according to the first and second embodiments of the present invention, the case where the number of vanes is two has been described. However, the same effect can be obtained when the number of vanes is one or three or more. Is obtained.

  DESCRIPTION OF SYMBOLS 1 Airtight container, 2 motor, 3 compression mechanism, 4 oil sump, 5 suction pipe, 6 discharge pipe, 7 glass terminal, 8 axis | shaft, 8a 1st oil supply path, 9 oil pump mechanism, 10 cup, 10a suction inlet, 11 piston 11a vane groove, 12 cylinder, 12A end plate, 12a cylindrical portion, 12b arc-shaped groove, 13 compression chamber, 14a first vane, 14b second vane, 15 housing, 15a upper bearing, 15b suction port, 15c discharge Port, 15ca through hole, 15cb through hole, 15d communication path, 16 frame, 16A disc, 16a hollow part, 16b lower bearing, 16c cylinder bearing, 16d communication path, 16e second oil supply path, 16f oil return hole, 17a Seal mechanism, 17b Seal mechanism, 18 Back pressure chamber, 18a Notch, 19 Bleed hole, 20 Discharge valve, 21 Lid, 30 first space, 31 second space, 41 stator, 42 rotor.

Claims (4)

A sealed container;
A housing fixedly provided in the sealed container and provided with a suction port and a discharge port;
A shaft rotatably supported relative to the housing and driven by drive means;
A frame fixed to the housing and rotatably supporting the shaft;
A columnar piston fixed to the shaft and rotating integrally with the shaft;
A cylindrical portion that accommodates the piston in an eccentric state; and an end plate that closes an opening at one end of the cylindrical portion, and the inside of the frame that is fixed to the housing that closes the opening at the other end of the cylindrical portion A cylinder that is rotatably supported by the cylinder and rotates in the same direction as the piston;
Means for synchronously rotating the piston and the cylinder;
At least one which is slidably mounted in at least one vane groove provided on the outer periphery of the piston, and whose tip is in sliding contact with the inner cylinder surface of the cylinder, thereby forming a compression chamber in the space in the cylinder. With the above vanes,
A back pressure chamber that is airtightly partitioned from the surrounding space is provided between the back surface of the end plate of the cylinder and the frame, and a bleed hole that penetrates the end plate of the cylinder and communicates with the compression chamber. The rotary compressor is characterized in that the bleed hole communicates with the back pressure chamber only in a certain section during one rotation of the cylinder, and gas during compression is supplied to the back pressure chamber. .   The back pressure chamber is formed in an annular shape, and has a configuration in which a cut portion is formed in a part of the peripheral surface thereof, and the cut portion communicates with the bleed hole only in a certain section during one rotation of the cylinder. The rotary compressor according to claim 1, wherein   A groove for accommodating the tip of the vane is provided on an inner cylinder surface of the cylinder, and the piston and the cylinder rotate in synchronization by the tip of the vane being pressed into the groove. The rotary compressor according to claim 1 or 2.   3. The rotary compressor according to claim 1, wherein an Oldham coupling is used as means for rotating the piston and the cylinder synchronously.

Images