JP2005146961A - Suction structure in compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the performance of a piston compressor without lowering the reliability of a suction valve in the piston compressor. <P>SOLUTION: A heat insulating member 44 is inserted in an annular recess 27. The heat insulating member 44 consists of a chamber heat insulating member 441 to cover an inner wall surface 482 of a peripheral wall 48, an inner wall surface 491 of an end wall 49, and an peripheral wall surface 291 of a partition wall 29, and a passage heat insulating member 442 to cover a peripheral wall surface 331 forming a suction passage 33. An suction passage 45 is formed in the chamber heat insulating member 441 of the heat insulating member 44. A passage cross sectional area in the suction port 141 is set greater than the passage cross sectional area in the suction passage 45. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a suction structure in a piston type compressor.

In a piston compressor (see, for example, Patent Documents 1 and 2), refrigerant gas in a suction chamber formed in a housing connected to a cylinder receives heat from the housing. The temperature of the refrigerant gas in the suction chamber affects the performance of the compressor. The higher the temperature of the refrigerant gas in the suction chamber, the lower the density of the refrigerant gas introduced into the compression chamber, so that the performance of the compressor decreases.
Japanese Utility Model Publication No. 52-164709 JP-A-6-317249

  If the heat transfer from the housing to the refrigerant gas in the suction chamber is reduced, the temperature rise of the refrigerant gas sucked into the compression chamber can be reduced. Increasing the flow rate of the refrigerant gas in the suction chamber is also effective as a measure for reducing heat transfer from the housing to the refrigerant gas in the suction chamber. The refrigerant gas in the suction chamber is sucked into the compression chamber by pushing away a suction valve that opens and closes the suction port on the way from the suction chamber to the compression chamber. If the flow rate of the refrigerant gas is too high, the intake valve is shockedly opened and easily damaged, and the reliability of the intake valve in the piston compressor is reduced.

  An object of the present invention is to improve the performance of a piston compressor without lowering the reliability of a suction valve in the piston compressor.

  Therefore, the present invention accommodates a piston in a cylinder bore formed in a cylinder, partitions a compression chamber in the cylinder bore, forms a suction pressure region and a discharge pressure region in a cover housing connected to the cylinder, The present invention is directed to a piston-type compressor that reciprocally drives the piston in the cylinder bore based on rotation of a rotating shaft and sucks refrigerant gas from the suction pressure region to the compression chamber via a suction port. In this invention, the flow passage sectional area of the suction port is made larger than the flow passage sectional area in the suction pressure region immediately upstream of the suction port.

  By reducing the flow path cross-sectional area in the suction pressure region upstream of the suction port, the flow rate of the refrigerant gas in the suction pressure region can be increased, and heat transfer from the cover housing to the refrigerant gas is reduced.

  Since the flow passage cross-sectional area at the suction port is larger than the flow passage cross-sectional area in the suction pressure region immediately upstream of the suction port, the flow velocity of the refrigerant gas flowing from the suction pressure region to the suction port is reduced. This deceleration contributes to avoiding a decrease in the reliability of the intake valve that opens and closes the intake port.

  According to a second aspect of the present invention, in the first aspect, an introduction flow path for introducing a refrigerant gas from the outside of the compressor into the cover housing is provided as a part of the suction pressure region, and the downstream of the introduction flow path. In addition, the suction flow path that communicates with the introduction flow path and the suction port is provided as a part of the suction pressure region, and extends along the suction flow path from a connection portion between the suction flow path and the introduction flow path. On the way to the downstream, the channel cross-sectional area of the suction channel was changed to be small.

  The configuration in which the cross-sectional area of the suction channel is changed to be smaller on the way from the connecting portion between the suction channel and the introduction channel to the downstream side of the suction channel is a decrease in gas flow rate in the suction channel. It is effective for prevention.

  At least a part of the flow path cross-sectional area in the suction flow path may be larger than the flow path cross-sectional area in the suction port. For example, the channel cross-sectional area of the suction channel in the vicinity of the connection portion between the suction channel and the introduction channel may be larger than the channel cross-sectional area of the suction port.

According to a third aspect of the present invention, in any one of the first and second aspects, a heat insulating member is accommodated in the cover housing, and the suction pressure region is formed in the heat insulating member.
The heat insulating member reduces heat transfer from the cover housing to the refrigerant gas.

According to a fourth aspect of the present invention, in the third aspect, the heat insulating member is made of a synthetic resin.
Synthetic resin is suitable as a heat insulating member and is advantageous for avoiding an increase in the weight of the compressor.
According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the suction pressure region is on an outer peripheral side of the cover housing, and the discharge pressure region is arranged around the axis of the rotation shaft. It was supposed to be surrounded.

The configuration in which the suction pressure region is provided on the outer peripheral side (the side close to the atmosphere) of the cover housing is preferable for suppressing the heating of the refrigerant gas in the suction pressure region.
According to a sixth aspect of the present invention, in the fifth aspect, the suction pressure region and the discharge pressure region are partitioned within the cover housing by an annular partition wall, and a plurality of nut portions are provided inside the outer peripheral wall of the cover housing. In addition, a plurality of screws are screwed into the plurality of nut portions to connect the cylinder and the cover housing, and a fillet recess is provided between a pair of nut portions adjacent in the circumferential direction of the outer peripheral wall, The heat insulating member was inserted between the outer peripheral wall and the partition wall so as to fill the meat-removing recess.

The configuration in which the gap between the adjacent nut portions is a meat recess is effective for reducing the weight of the cover housing itself.
According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the refrigerant gas is carbon dioxide.

  Carbon dioxide used as a refrigerant in a higher pressure state than the chlorofluorocarbon gas requires a small gas flow rate. The smaller the gas flow rate, the more important it is to prevent the refrigerant gas from being heated in the suction pressure region. The present invention is suitable for application to a compressor using carbon dioxide as a refrigerant.

  The present invention has an excellent effect that the performance of the piston compressor can be enhanced without reducing the reliability of the suction valve in the piston compressor.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, an aluminum front housing 12 is joined to the front end of an aluminum cylinder 11. An aluminum rear housing 13 as a cover housing is joined and fixed to the rear end of the cylinder 11 via a valve plate 14 and a valve forming plate 15. The cylinder 11, the front housing 12 and the rear housing 13 are coupled together by screws 43. As shown in FIG. 5, a plurality of nut portions 481 are formed on the outer peripheral wall 48 of the rear housing 13. The screw 43 is screwed into the nut portion 481. The cylinder 11, the front housing 12, and the rear housing 13 constitute an entire housing of the variable capacity piston compressor 16.

  As shown in FIG. 1, a rotary shaft 18 is rotatably supported via radial bearings 19 and 20 on the front housing 12 and the cylinder 11 forming the control pressure chamber 121. The rotating shaft 18 that protrudes outside from the control pressure chamber 121 obtains driving force from the vehicle engine 17 that is an external driving source via a pulley (not shown) and a belt (not shown).

  A rotary support 21 is fixed to the rotary shaft 18, and a swash plate 22 is supported so as to be slidable and tiltable in the axial direction of the rotary shaft 18. A connecting piece 23 is fixed to the swash plate 22, and a guide pin 24 is fixed to the connecting piece 23. A guide hole 211 is formed in the rotary support 21. The head of the guide pin 24 is slidably fitted into the guide hole 211. The swash plate 22 can be tilted in the axial direction of the rotary shaft 18 and can rotate integrally with the rotary shaft 18 by the linkage of the guide hole 211 and the guide pin 24. The tilt of the swash plate 22 is guided by the slide guide relationship between the guide hole 211 and the guide pin 24 and the slide support action of the rotary shaft 18.

  When the center portion of the swash plate 22 moves to the rotation support 21 side, the inclination angle of the swash plate 22 increases. The maximum inclination angle of the swash plate 22 is regulated by the contact between the rotary support 21 and the swash plate 22. The solid line position of the swash plate 22 in FIG. 1 indicates the maximum tilt angle state of the swash plate 22. When the central portion of the swash plate 22 moves to the cylinder 11 side, the inclination angle of the swash plate 22 decreases. The chain line position of the swash plate 22 in FIG. 1 indicates the minimum tilt angle state of the swash plate 22.

  Pistons 25 are accommodated in a plurality of cylinder bores 111 penetrating the cylinder 11. The rotational movement of the swash plate 22 is converted into the back-and-forth reciprocating movement of the piston 25 via the shoe 26, and the piston 25 is reciprocated within the cylinder bore 111. The piston 25 defines a compression chamber 112 in the cylinder bore 111.

  As shown in FIG. 1, a suction port 141 and a discharge port 142 are formed in the valve plate 14 and the valve forming plate 15. A suction valve 151 is formed on the valve forming plate 15, and a discharge valve 301 is formed on the valve forming plate 30.

  As shown in FIGS. 1 and 5, an annular recess 27 and a discharge chamber 28 are defined in the rear housing 13 by an annular partition wall 29. The annular recess 27 is on the outer peripheral side of the rear housing 13 and surrounds the discharge chamber 28 that is a part of the discharge pressure region around the axis 181 of the rotating shaft 18.

  As shown in FIG. 1, a suction passage 33 and a discharge passage 34 are formed in the end wall 49 of the rear housing 13. In the discharge chamber 28, a valve forming plate 30 and a retainer 31 are coupled to the valve plate 14 by tightening screws 32.

  As shown in FIG. 4A, the heat insulating member 44 is inserted into the annular recess 27. The heat insulating member 44 housed in the rear housing 13 is a room heat insulating member 441 that covers the inner wall surface 482 of the outer peripheral wall 48 of the rear housing 13, the inner wall surface 491 of the end wall 49, and the outer peripheral wall surface 291 of the partition wall 29. And a passage heat insulating member 442 that covers the peripheral wall surface 331 that forms the suction passage 33.

  A thinning recess 483 is formed between a pair of adjacent nut portions 481 on the inner side of the outer peripheral wall 48 of the rear housing 13. The bottom surface of the meat removal recess 483 is an inner wall surface 482 of the outer peripheral wall 48. The room heat insulating member 441 of the heat insulating member 44 is provided between the outer peripheral wall 48 and the partition wall 29 so as to fill a fillet concave portion 483 between a pair of nut portions 481 adjacent in the circumferential direction of the outer peripheral wall 48 of the rear housing 13. Has been inserted.

  As shown in FIG. 2, an annular groove-shaped suction channel 45 is formed in the room heat insulating member 441 of the heat insulating member 44. The annular suction channel 45 surrounds the axis 181 of the rotating shaft 18. The cross-sectional shape (rectangular shape) of the suction channel 45 is the same shape and size at any location, and the cross-sectional area of the suction channel 45 is the same at any location. The suction flow path 45 and the suction port 141 are connected at a right angle, and the suction flow path 45 communicates with the suction port 141. As shown in FIG. 4A, an internal passage 443 is formed in the passage heat insulating member 442 and the room heat insulating member 441 of the heat insulating member 44. The internal passage 443 communicates with the suction flow path 45.

As shown in FIG. 4B, the width W of the suction flow path 45 that is the suction pressure region is smaller than the diameter R of the suction port 141. If the groove depth of the groove-shaped suction channel 45 is H (shown in FIG. 4A), the channel cross-sectional area π × (R / 2) ² in the suction port 141 is the channel in the suction channel 45. The cross-sectional area is larger than W × H. That is, the flow path cross-sectional area at the suction port 141 is larger than the flow path cross-sectional area at the suction flow path 45 immediately upstream of the suction port 141. In other words, the flow path cross-sectional area in the refrigerant gas flow path from the suction flow path 45 to the suction port 141 increases when the position on the flow path changes from the suction flow path 45 to the suction port 141. Note that the suction flow path 45 immediately upstream of the suction port 141 is a portion of the suction pressure region immediately after the suction port 141 with respect to the flow path of the refrigerant gas.

The cross-sectional area of the internal passage 443 is larger than the cross-sectional area of the suction passage 45.
As shown in FIG. 4A, a heat insulating member 46 is inserted into the discharge chamber 28. The heat insulating member 46 accommodated in the rear housing 13 includes a chamber heat insulating member 461 that covers the inner wall surface 492 of the end wall 49 and the inner peripheral wall surface 292 of the partition wall 29, and a peripheral wall surface 341 that forms the discharge passage 34. And a passage heat insulating member 462 to be covered. That is, the heat insulating member 46 covers the formation wall surface (the inner wall surface 492, the inner peripheral wall surface 292, and the peripheral wall surface 341) that forms the discharge pressure region including the discharge chamber 28 and the discharge passage 34.

  The gaseous refrigerant in the suction passage 45 is sucked into the compression chamber 112 by pushing the suction valve 151 away from the suction port 141 by the backward movement of the piston 25 (movement from the right side to the left side in FIG. 1). The suction valve 151 is in contact with the bottom of the position restricting recess 113 and the opening degree is restricted. The gaseous refrigerant sucked into the compression chamber 112 is discharged into the discharge chamber 28 by pushing the discharge valve 301 away from the discharge port 142 by the forward movement of the piston 25 (movement from the left side to the right side in FIG. 1). The discharge valve 301 is in contact with the retainer 31 and the opening degree is regulated.

  As shown in FIG. 1, the suction passage 33 for introducing the gaseous refrigerant into the suction passage 45 and the discharge passage 34 for discharging the gaseous refrigerant from the discharge chamber 28 are connected by an external refrigerant circuit 35. . On the external refrigerant circuit 35, a heat exchanger 36 for removing heat from the refrigerant, a fixed throttle 37, a heat exchanger 38 for transferring ambient heat to the refrigerant, and an accumulator 39 are interposed. The accumulator 39 is for sending only the gaseous refrigerant to the compressor. The refrigerant in the discharge chamber 28 flows into the suction passage 45 via the discharge passage 34, the heat exchanger 36, the fixed throttle 37, the heat exchanger 38, the accumulator 39, and the suction passage 33 (internal passage 443). The refrigerant gas flowing into the suction flow path 45 from the connection portion 444 between the internal passage 443 and the suction flow path 45 is divided into the right side and the left side from the connection portion 444 in FIG.

  The internal passage 443 is an introduction passage for introducing the refrigerant gas into the rear housing 13 from the outside of the variable displacement piston compressor 16. The suction flow path 45 is downstream of an internal passage 443 serving as an introduction flow path provided as a part of the suction pressure region, and is connected to the suction port 141. The cross-sectional area of the internal passage 443 is larger than the cross-sectional area of the suction passage 45 provided as a part of the suction pressure region. The cross-sectional area of the flow path in the internal passage 443 gradually decreases from the middle toward the downstream side from the upstream side.

  The discharge chamber 28 and the control pressure chamber 121 are connected by a supply passage 40. Further, the control pressure chamber 121 and the suction passage 45 are connected by a discharge passage 41. The refrigerant in the control pressure chamber 121 flows out to the suction flow path 45 through the discharge passage 41.

  An electromagnetic capacity control valve 42 is interposed on the supply passage 40. The capacity control valve 42 is in a valve-closed state where refrigerant cannot flow in the demagnetized state, and refrigerant supply from the discharge chamber 28 to the control pressure chamber 121 via the supply passage 40 is not performed. Since the refrigerant in the control pressure chamber 121 flows out to the suction passage 45 through the discharge passage 41, the pressure in the control pressure chamber 121 decreases. Accordingly, the inclination angle of the swash plate 22 increases and the discharge capacity increases. The capacity control valve 42 is in an open state in which the refrigerant can flow by excitation, and the refrigerant is supplied from the discharge chamber 28 to the control pressure chamber 121 via the supply passage 40. Therefore, the pressure in the control pressure chamber 121 increases, the inclination angle of the swash plate 22 decreases, and the discharge capacity decreases.

In the present embodiment, the heat insulating members 44 and 46 are made of synthetic resin. Carbon dioxide is used as a refrigerant.
In the first embodiment, the following effects can be obtained.

  (1-1) With the operation of the variable displacement piston compressor 16, the inside of the discharge chamber 28 and the discharge passage 34 where the compressed refrigerant gas exists becomes hot, and the temperature of the rear housing 13 and the valve plate 14 is increased. Rise. If the heat insulating member 44 is not accommodated in the annular recess 27, the refrigerant gas introduced into the rear housing 13 from the external refrigerant circuit 35 is the annular recess 27 corresponding to a conventional suction chamber (see, for example, Patent Documents 1 and 2). Will flow into. Since the flow path cross-sectional area in the annular recess 27 is larger than the flow path cross-sectional area in the suction passage 33, the refrigerant gas that has flowed into the annular recess 27 from the suction path 33 is decelerated. Therefore, heat is easily transmitted from the rear housing 13 or the valve plate 14 to the refrigerant gas in the annular recess 27, and the refrigerant gas in the annular recess 27 is easily heated.

  In the present embodiment, the heat insulating member 44 accommodated in the annular recess 27 is provided with the suction flow path 45 and the internal passage 443, and the flow path cross-sectional area in the suction flow path 45 leading to the suction port 141 is changed to that in the conventional suction chamber. It is smaller than the area. By reducing the cross-sectional area of the suction passage 45 that is the suction pressure region, the flow rate of the refrigerant gas in the suction passage 45 is increased. Therefore, heat transfer from the rear housing 13 and the valve plate 14 to the refrigerant gas is reduced, and the performance of the compressor is improved.

  If the flow rate of the refrigerant gas in the suction port 141 is excessive, the suction valve 151 that opens and closes the suction port 141 is shockedly opened and collides with the bottom of the position restricting recess 113. As a result, the intake valve 151 is easily damaged, and the reliability of the intake valve 151 is reduced.

The cross-sectional area π × (R / 2) ² of the suction port 141 is larger than the cross-sectional area W × H of the suction channel 45. That is, the flow path cross-sectional area of the suction port 141 is larger than the flow path cross-sectional area of the suction flow path 45 immediately upstream of the suction port 141, so that the refrigerant gas flowing from the suction flow path 45 into the suction port 141 The flow rate of is slowed down. The deceleration of the refrigerant gas in the suction port 141 is effective in preventing the suction valve 151 from being shockedly opened, and the suction valve 151 is hardly damaged. That is, the configuration in which the flow path cross-sectional area at the suction port 141 is larger than the flow path cross-sectional area at the suction flow path 45 is effective in avoiding a decrease in the reliability of the suction valve 151.

  (1-2) Since the flow passage cross-sectional area in the internal passage 443 as the introduction flow passage is larger than the flow passage cross-sectional area in the suction flow passage 45, the flow rate of the refrigerant gas that has passed through the internal passage 443 is set to the suction flow passage 45. It is possible to increase the speed. The cross-sectional area of the flow path in the internal passage 443 gradually decreases from the middle toward the downstream side from the upstream side. The configuration in which the cross-sectional area of the internal passage 443 is gradually changed contributes to smooth flow of the refrigerant gas from the internal passage 443 to the suction passage 45.

  (1-3) The heat insulating member 44 is made of a synthetic resin having a low thermal conductivity. The heat insulating member 44 reduces heat transfer from the aluminum rear housing 13 having a high thermal conductivity to the refrigerant gas in the suction flow path 45 that is the suction pressure region. Therefore, the heat insulation efficiency in the suction flow path 45 is high, and the performance of the compressor is improved.

  (1-4) Synthetic resin is suitable as a material for the heat insulating member 44. Compared to the case where the suction passage 45 is directly formed in the rear housing 13, the configuration in which the suction passage 45 is formed in the heat insulating member 44 is advantageous in avoiding an increase in the weight of the variable displacement piston compressor 16.

  (1-5) The suction passage 45 that is the suction pressure region is on the outer peripheral side of the rear housing 13, and the discharge chamber 28 is surrounded by the suction passage 45 around the axis 181 of the rotating shaft 18. The configuration in which the suction passage 45 is provided on the outer peripheral side (the side close to the atmosphere) of the rear housing 13 is preferable in terms of suppressing the heating of the refrigerant gas in the suction passage 45.

  (1-6) The configuration in which the gap between the adjacent nut portions 481 is the thinned recess 483 is effective in reducing the weight of the rear housing 13 itself as a cover housing. The heat insulating member 44 accommodated in the annular recess 27 so as to fill the meat recess 483 is made of synthetic resin, which is advantageous for avoiding an increase in the weight of the variable displacement piston compressor 16.

  (1-7) Carbon dioxide used as a refrigerant at a higher pressure than chlorofluorocarbon gas requires a small gas flow rate. The smaller the gas flow rate, the more important it is to prevent the refrigerant gas from being heated in the suction pressure region. A variable displacement piston compressor 16 that uses carbon dioxide as a refrigerant is suitable as an application target of the present invention.

  (1-8) Since the accumulator 39 suppresses the suction pulsation, it is not necessary to provide a suction chamber in the rear housing 13 for suppressing the suction pulsation. In the present invention in which the cross-sectional area of the suction flow path 45 in the rear housing 13 is desired to be reduced, the piston compressor used as a part of the refrigeration circuit in which the accumulator 39 is disposed on the external refrigerant circuit 35 is applied to the present invention. Suitable as a target.

  (1-9) The heat insulating member 46 made of synthetic resin that covers the formation wall surface (the inner wall surface 492, the inner peripheral wall surface 292, and the peripheral wall surface 341) that forms the discharge pressure region has the discharge pressure region (the discharge chamber 28 and the discharge passage 34). ) To reduce heat transfer from the refrigerant gas to the rear housing 13. Reduction of heat transfer from the refrigerant gas in the discharge pressure region to the rear housing 13 leads to suppression of heat transfer from the rear housing 13 to the refrigerant gas in the suction pressure region.

Next, a second embodiment shown in FIGS. 6A and 6B will be described. The same reference numerals are used for the same components as those in the first embodiment.
The width Wa of the suction channel 45A is larger than the diameter R of the suction port 141, but the channel cross-sectional area Wa × Ha (Ha is the groove depth of the suction channel 45A) in the annular recess 27A is the suction port. 141 is smaller than the channel cross-sectional area π × (R / 2) ² .

In the second embodiment, the same effect as in the first embodiment can be obtained.
Next, a third embodiment of FIG. 7 will be described. The same reference numerals are used for the same components as those in the first embodiment.

  A flat heat insulating member 47 is interposed between the heat insulating member 44 including the chamber heat insulating member 441 and the passage heat insulating member 442 and the valve plate 14. In the heat insulating member 47 made of synthetic resin, a conical connection hole 471 is formed so as to correspond to the suction port 141. The maximum diameter side of the conical connection hole 471 is connected to the suction port 141, and the minimum diameter side of the connection hole 471 is connected to the suction flow path 45. The suction channel 45 communicates with the suction port 141 through the connection hole 471. The maximum diameter of the conical connection hole 471 is made to coincide with the diameter R of the suction port 141, and the flow passage cross-sectional area at the minimum diameter portion of the connection hole 471 is made to coincide with the flow passage cross-sectional area of the suction flow path 45. is there.

  In the third embodiment, the heat insulating member 47 made of synthetic resin suppresses heat transfer from the valve plate 14 to the refrigerant gas in the suction flow path 45, and the heat insulation efficiency in the suction flow path 45 is the case of the first embodiment. It improves further than.

Next, a fourth embodiment shown in FIGS. 8A and 8B will be described. The same reference numerals are used for the same components as those in the first embodiment.
As shown in FIG. 8B, the suction flow channel 45B is composed of a flow channel 451 above the line L and a flow channel 452 below the line L, and the width Wb2 of the lower flow channel 452 is shown. Is smaller than the width Wb1 of the upper flow path 451. Since the groove depths of the upper channel 451 and the lower channel 452 are the same, the channel cross-sectional area of the lower channel 452 is larger than the channel cross-sectional area of the upper channel 451. small. That is, the cross-sectional area of the suction flow path 45B changes so as to decrease in the middle of the downstream along the suction flow path 45B from the connection section 444 between the internal passage 443 as the introduction flow path and the suction flow path 45B. To do.

  Since the refrigerant gas flows from the flow path 451 into the suction port 141 above the line L, if the flow path cross-sectional area in the upper flow path 451 and the flow path cross-sectional area in the lower flow path 452 are the same, The flow rate of the refrigerant gas in the lower flow path 452 is slower than the flow speed of the refrigerant gas in the upper flow path 451.

  In this embodiment, the channel cross-sectional area of the lower channel 452 is such that the refrigerant gas flow rate in the lower channel 452 is approximately the same as the refrigerant gas flow rate in the upper channel 451. It is smaller than the channel cross-sectional area in the channel 451. Therefore, the heat transfer from the rear housing 13 or the valve plate 14 to the refrigerant gas in the lower flow path 452 is almost the same as the heat transfer from the rear housing 13 or the valve plate 14 to the refrigerant gas in the upper flow path 451. It becomes. A configuration in which the flow path cross-sectional areas of the flow paths 451 and 452 are different is preferable in terms of suppressing heat transfer from the rear housing 13 and the valve plate 14 to the refrigerant gas in the suction flow path 45B.

Next, a fifth embodiment shown in FIGS. 9A and 9B will be described. The same reference numerals are used for the same components as those in the first embodiment.
In each of the above embodiments, the thinning recess 483 is formed inside the outer peripheral wall 48 of the rear housing 13, but in the fifth embodiment, the thinning recess 484 is formed outside the outer peripheral wall 48. Also, a meat recess 114 is formed on the outer surface of the cylinder 11.

  The presence of the meat recess 484 brings about a weight reduction of the rear housing 13, and the meat catching recess 114 brings about a weight reduction of the cylinder 11. Further, since the volume of the annular recess 27D is smaller than the volume of the annular recess 27 of the first embodiment, the volume of the heat insulating member 44D is also smaller than that of the heat insulating member 44 in the first embodiment. The presence of the meat recesses 484 and 114 contributes to weight reduction of the entire variable displacement piston compressor 16.

In the present invention, the following embodiments are also possible.
(1) Hard rubber may be used as the material of the heat insulating members 44 and 46.
(2) In the fourth embodiment, the width of the upper channel 451 and the width of the lower channel 452 are the same, and the groove depth of the lower channel 452 is set to the groove depth of the upper channel 451. You may make it make smaller than this.

  (3) In the fourth embodiment, the flow passage cross-sectional area in the suction flow passage 45B is changed in two stages, but the flow passage cross-sectional area in the suction flow path may be changed in three stages or more. . In this case, the change in the cross-sectional area of the flow path may be reduced stepwise as the distance from the connecting portion 444 between the internal passage 443 and the suction flow path 45B increases toward the downstream side along the suction flow path.

  Alternatively, as the distance from the connecting portion 444 between the internal passage 443 and the suction flow path 45B moves downstream along the suction flow path, the cross-sectional area of the suction flow path may gradually decrease. .

(4) In the first embodiment, the cross-sectional area of the suction channel 45 in the vicinity of the connecting portion 444 may be larger than the cross-sectional area of the suction port 141.
(5) The suction passage 45 may be formed directly in the rear housing 13.

  (6) The present invention may be applied to a piston type compressor in which a discharge pressure region is provided on the outer peripheral side of the rear housing 13 and the suction pressure region is surrounded by the discharge pressure region around the axis 181 of the rotating shaft 18.

(7) The present invention may be applied to a fixed displacement type piston compressor.
(8) The present invention may be applied to a compressor using a refrigerant other than carbon dioxide.
The technical idea that can be grasped from the embodiment described above will be described below.

  [1] The piston-type compressor includes a plurality of cylinder bores around an axis of the rotary shaft, and forms an annular suction channel surrounding the axis of the rotary shaft as a part of the suction pressure region. The suction structure in a piston compressor according to any one of claims 1 to 7, wherein the annular suction passage is communicated with each suction port communicating with a plurality of cylinder bores.

  [2] The suction structure in the piston compressor according to [1], wherein the suction flow path and the suction port are connected at right angles.

The side sectional view of the whole compressor which shows a 1st embodiment. AA sectional view taken on the line AA of FIG. BB sectional drawing of FIG. (A) is a principal part expanded sectional side view. (B) is CC sectional view taken on the line of (a). FIG. A 2nd embodiment is shown and (a) is an important section side sectional view. (B) is the DD sectional view taken on the line of (a). The principal part sectional side view which shows 3rd Embodiment. A 4th embodiment is shown and (a) is an important section side sectional view. (B) is the EE sectional view taken on the line of (a). A 5th embodiment is shown and (a) is an important section side sectional view. (B) is the FF sectional view taken on the line of (a).

Explanation of symbols

  11 ... Cylinder. 111 ... Cylinder bore. 112: Compression chamber. 13 ... A rear housing as a cover housing. 141: Inhalation port. 151 ... Suction valve. 16: Variable displacement piston compressor. 18 ... Rotating shaft. 181 ... axis. 25 ... Piston. 28: A discharge chamber serving as a discharge pressure region. 29 ... partition wall. 43 ... Screw. 44, 44D, 47 ... heat insulating members. 443 ... Internal passage as introduction channel. 444: Connection portion. 45: A suction flow path that is a suction pressure region. 48: outer peripheral wall. 481 ... Nut portion. 483: Meat removal recess.

Claims (7)

A piston is accommodated in a cylinder bore formed in the cylinder, a compression chamber is defined in the cylinder bore, a suction pressure region and a discharge pressure region are formed in a cover housing connected to the cylinder, and based on rotation of the rotary shaft A piston-type compressor that reciprocally drives the piston in the cylinder bore and sucks refrigerant gas from the suction pressure region to the compression chamber via a suction port;
A suction structure in a compressor, wherein a flow passage cross-sectional area of the suction port is larger than a flow passage cross-sectional area in the suction pressure region immediately upstream of the suction port.   An introduction flow path for introducing refrigerant gas from the outside of the compressor into the cover housing is provided as a part of the suction pressure region, communicates with the introduction flow path downstream of the introduction flow path, and A suction channel that communicates with the port is provided as a part of the suction pressure region, and in the middle of the suction channel and downstream from the connection portion between the suction channel and the introduction channel, The suction structure in the compressor according to claim 1, wherein the flow passage cross-sectional area is changed to be small.   The suction structure in the compressor according to claim 1, wherein a heat insulating member is accommodated in the cover housing, and the suction pressure region is formed in the heat insulating member.   The suction structure in the compressor according to claim 3, wherein the heat insulating member is made of a synthetic resin.   The compressor according to any one of claims 1 to 4, wherein the suction pressure region is on an outer peripheral side of the cover housing and surrounds the discharge pressure region around an axis of the rotation shaft. Inhalation structure.   The suction pressure region and the discharge pressure region are partitioned in the cover housing by an annular partition wall, and a plurality of nut portions are provided inside the outer peripheral wall of the cover housing, and a plurality of screws are attached to the plurality of nut portions. The cylinder and the cover housing are connected by screwing, and a meat recess is provided between a pair of nut portions adjacent to each other in the circumferential direction of the outer peripheral wall, and the heat insulating member is disposed so as to fill the meat recess The suction structure in the compressor according to claim 5, wherein the suction structure is inserted between an outer peripheral wall and the partition wall.   The suction structure for a compressor according to any one of claims 1 to 6, wherein the refrigerant gas is carbon dioxide.

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