JP2009097379A - Refrigerant suction structure in double-headed piston type compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent temperature of refrigerant compressed in a compression chamber from getting high in a double-headed piston type compressor. <P>SOLUTION: A first rotary valve 35 and a second rotary valve 36 are provided on a rotary shaft 21 with corresponding to cylinder blocks 11, 12. A shaft inside passage 31 is formed in the rotary shaft 21 along a rotary axis line 210 of the rotary shaft 21. An inlet 311 of the shaft inside passage 31 opens to a suction chamber 142 in a rear housing 14. A first communication passage 32 is formed in the cylinder block 11 to communicate to a first cylinder bore 27. A second communication passage 33 is formed in the cylinder block 12 to communicate to a second cylinder bore 28. Outlets 312, 313 of the shaft inside passage 31 intermittently communicate to communication passages 32, 33 with accompanying rotation of the rotary shaft 21. The first communication passage 32 and the second communication passage 33 have round section shapes, and diameter of the first communication passage 32 is larger than that of the second communication passage 33. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention includes a rotary valve having an introduction passage for introducing a refrigerant from a suction pressure region into a compression chamber defined in a cylinder bore by a double-headed piston, and the rotary valve rotates integrally with the rotary shaft. The present invention relates to a refrigerant suction structure in a compressor.

  A double-headed piston compressor using a rotary valve (see, for example, Patent Document 3) is sucked into a cylinder bore as compared to a double-headed piston compressor using a reed valve type suction valve (see, for example, Patent Document 2). Low inhalation resistance when inhaling gas and excellent energy efficiency.

  In the compressor disclosed in Patent Document 3, the double-headed piston interlocking with the rotation of the rotary shaft is accommodated in a front cylinder bore and a rear cylinder bore that are paired in the front and rear, and the double-headed piston defines a compression chamber in the front cylinder bore. In addition, a compression chamber is defined in the rear cylinder bore. A front rotary valve and a rear rotary valve are integrally formed on the rotary shaft. A supply passage is formed in the rotation shaft, and the front rotary valve and the rear rotary valve have outlets of the supply passage. A communication path is formed in the cylinder block so as to communicate with the compression chamber, and an outlet of the supply path is intermittently communicated with the communication path as the rotary shaft rotates, that is, the rotary valve rotates. When the outlet of the supply passage communicates with the communication passage, the refrigerant in the supply passage flows into the compression chamber.

  As the cross-sectional shape of the communication path, a long hole shape that is long in the axial direction of the rotating shaft is employed as disclosed in Patent Document 1, for example. Adoption of the long hole shape is performed in order to collect residual gas in the compression chamber and increase volumetric efficiency.

The supply passage communicates with a suction chamber in the rear housing, and refrigerant in the suction chamber is supplied to the compression chamber on the front cylinder bore side and the compression chamber on the rear cylinder bore side via the supply passage. Refrigerant in the compression chamber on the front cylinder bore side is discharged to the discharge chamber in the front housing by pushing away the discharge valve, and refrigerant in the compression chamber on the rear cylinder bore side is discharged to the discharge chamber in the rear housing by pushing away the discharge valve. The
JP-A-6-129350 JP 2000-145629 A JP 2007-32445 A

  The refrigerant pressure in the discharge chamber on the front housing side is the same as the refrigerant pressure in the discharge chamber on the rear housing side, and the refrigerant in the compression chamber is compressed in the compression chamber until the pressure in the discharge chamber is reached. Therefore, the smaller the amount of refrigerant supplied to the compression chamber, the higher the refrigerant compression ratio. However, the higher the compression ratio, the higher the temperature of the compressed refrigerant.

  The distance from the suction chamber via the supply passage to the compression chamber on the front cylinder bore side is longer than the distance from the suction chamber via the supply passage to the compression chamber on the rear cylinder bore side. Therefore, while the communication path communicating with the compression chamber on the front cylinder bore side and the outlet on the front rotary valve communicate with each other, the amount of refrigerant supplied to the compression chamber on the front cylinder bore side is the compression chamber on the rear cylinder bore side. The amount of refrigerant supplied to the compression chamber on the rear cylinder bore side is small while the communication path communicating with the outlet and the outlet on the rear rotary valve communicate with each other. Therefore, the temperature of the refrigerant compressed in the compression chamber on the front cylinder bore side becomes higher than the temperature of the refrigerant compressed in the compression chamber on the rear cylinder bore side.

  If the temperature of the refrigerant compressed in the compression chamber on the front cylinder bore side becomes too high, the front housing becomes hot and the sealing function of the seal member interposed between the front housing housing and the cylinder block is impaired.

  An object of this invention is to suppress the high temperature of the refrigerant | coolant compressed in the compression chamber in a double-headed piston type compressor.

  In the present invention, a double-headed piston interlocking with the rotation of the rotating shaft is accommodated in a pair of a first cylinder bore and a second cylinder bore, and a refrigerant is supplied from a suction pressure region to a first compression chamber defined in the first cylinder bore. And a second rotary passage having a first introduction passage for introducing refrigerant from the suction pressure region into a second compression chamber defined in the second cylinder bore. A rotary valve is provided, and communicates with the first compression chamber and communicates with the first introduction passage, and communicates with the second compression chamber and communicates with the second introduction passage. A second communication passage is provided in the cylinder block, and at least a part of the first introduction passage and the second introduction passage is provided in the rotating shaft, and the second introduction passage is provided in the first passage. With part of the introduction passage The invention is directed to a refrigerant suction structure in a double-headed piston compressor, wherein the distance between the first introduction passages is longer than the distance between the second introduction passages. A cross-sectional shape of the passage and the second communication passage is circular, and a passage diameter in the first communication passage is larger than a passage diameter in the second communication passage.

  The configuration in which the passage diameter in the first communication passage is larger than the passage diameter in the second communication passage is the amount of refrigerant supplied to the first compression chamber via the first communication passage and the second communication passage. The difference from the amount of refrigerant supplied to the second compression chamber is reduced. Such a reduction in the difference in the refrigerant amount is effective in suppressing the increase in the temperature of the refrigerant compressed in the first compression chamber. Moreover, the structure which made the cross-sectional shape of a 1st communicating path and a 2nd communicating path circular is easy to process a 1st communicating path and a 2nd communicating path.

In a preferred example, the passage diameter in the first communication passage is 1.8 times or less than the passage diameter in the second communication passage.
Such a ratio of the passage diameters is effective in suppressing the high temperature of the refrigerant compressed in the first compression chamber.

In a preferred example, the passage diameter in the first communication passage is 1.4 times or less than the passage diameter in the second communication passage.
Such a ratio of the passage diameters makes the temperature of the refrigerant compressed in the first compression chamber lower than when the passage diameters of the first communication passage and the second communication passage are the same.

  The present invention has an excellent effect that the high temperature of the refrigerant compressed in the compression chamber in the double-headed piston compressor can be suppressed.

DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, a front housing 13 is connected to one cylinder block 11 of a pair of connected cylinder blocks 11, 12, and a rear housing 14 is connected to the other cylinder block 12. The cylinder blocks 11, 12, the front housing 13 and the rear housing 14 constitute an entire housing of the double-headed piston compressor 10. A discharge chamber 131 as a discharge pressure region in the compressor is formed in the front housing 13, and a discharge chamber 141 as a discharge pressure region in the compressor and a suction chamber 142 as a suction pressure region in the compressor are formed in the rear housing 14. Is formed. The inside of the compressor means the inside of the entire housing of the double-headed piston type compressor 10, and the outside of the compressor means the outside of the entire housing of the double-headed piston type compressor 10.

  A valve plate 15, a valve forming plate 16 and a retainer forming plate 17 are interposed between the cylinder block 11 and the front housing 13. A valve plate 18, a valve forming plate 19, and a retainer forming plate 20 are interposed between the cylinder block 12 and the rear housing 14. Discharge ports 151 and 181 are formed on the valve plates 15 and 18, and discharge valves 161 and 191 are formed on the valve forming plates 16 and 19. The discharge valves 161 and 191 open and close the discharge ports 151 and 181. Retainers 171 and 201 are formed on the retainer forming plates 17 and 20. The retainers 171 and 201 regulate the opening degree of the discharge valves 161 and 191.

  Gaskets (not shown) are appropriately interposed between the cylinder block 11 and the cylinder block 12, between the cylinder block 11 and the front housing 13, and between the cylinder block 12 and the rear housing 14. These gaskets are rubber seal layers provided on both surfaces of a metal plate. These gaskets prevent refrigerant leakage from between the cylinder blocks 11 and 12, between the cylinder block 11 and the front housing 13, and between the cylinder block 12 and the rear housing 14.

  A rotating shaft 21 is rotatably supported on the cylinder blocks 11 and 12. Shaft holes 111 and 121 are provided through the cylinder blocks 11 and 12, and a rotating shaft 21 is passed through the shaft holes 111 and 121. The outer peripheral surface of the rotating shaft 21 is in contact with the inner peripheral surfaces of the shaft holes 111 and 121, and the rotating shaft 21 is directly supported by the cylinder blocks 11 and 12 through the inner peripheral surfaces of the shaft holes 111 and 121. . The outer peripheral surface portion of the rotating shaft 21 in contact with the shaft hole 111 is a seal peripheral surface 211, and the outer peripheral surface portion of the rotating shaft 21 in contact with the shaft hole 121 is a seal peripheral surface 212.

  A swash plate 23 as a cam body is fixed to the rotating shaft 21. The swash plate 23 is accommodated in a swash plate chamber 24 between the cylinder blocks 11 and 12. A lip seal type shaft seal member 22 is interposed between the front housing 13 and the rotating shaft 21. The shaft seal member 22 prevents refrigerant leakage from between the front housing 13 and the rotating shaft 21. A protruding end portion of the rotating shaft 21 that protrudes outward from the front housing 13 is connected to a vehicle engine 26 that is an external drive source via an electromagnetic clutch 25. The rotating shaft 21 obtains a rotational driving force from the vehicle engine 26 via the electromagnetic clutch 25.

  As shown in FIG. 3A, the cylinder block 11 is formed with a plurality of first cylinder bores 27 arranged around the rotation shaft 21. As shown in FIG. 3B, the cylinder block 12 is formed with a plurality of second cylinder bores 28 arranged around the rotation shaft 21. A double-headed piston 29 is accommodated in a first cylinder bore 27 and a second cylinder bore 28 which form a pair in the front and rear (the front housing 13 side is the front side and the rear housing 14 is the rear side).

  As shown in FIG. 1, the rotational movement of the swash plate 23 that rotates integrally with the rotary shaft 21 is transmitted to the double-headed piston 29 via the shoe 30, and the double-headed piston 29 reciprocates back and forth in the cylinder bores 27 and 28. To do. The cylindrical head 291 of the double-headed piston 29 partitions the first compression chamber 271 in the first cylinder bore 27, and the cylindrical head 292 of the double-headed piston 29 partitions the compression chamber 281 in the second cylinder bore 28. To do.

  An in-axis passage 31 is formed in the rotating shaft 21 along the rotating axis 210 of the rotating shaft 21. An inlet 311 of the in-shaft passage 31 opens into the suction chamber 142 in the rear housing 14. A first outlet 312 of the in-shaft passage 31 is formed in the rotating shaft 21 in the shaft hole 111 so as to open to the seal peripheral surface 211 of the rotating shaft 21. A second outlet 313 of the in-shaft passage 31 is formed in the rotating shaft 21 in the shaft hole 121 so as to open to the seal peripheral surface 212 of the rotating shaft 21.

  As shown in FIGS. 2 (a) and 3 (a), a first communication path 32 is formed in the cylinder block 11 so as to communicate with the first cylinder bore 27 and the shaft hole 111. As shown in FIGS. 2A and 3B, a second communication passage 33 is formed in the cylinder block 12 so as to communicate with the second cylinder bore 28 and the shaft hole 121. As the rotary shaft 21 rotates, the first outlet 312 of the in-shaft passage 31 intermittently communicates with the first communication passage 32, and the second outlet 313 of the in-shaft passage 31 intermittently communicates with the second communication passage 33. Communicate with.

  When the double-headed piston 29 is in the suction stroke state on the first cylinder bore 27 side (stroke in which the double-headed piston 29 moves from the left side to the right side in FIG. 1), the first outlet 312 and the first communication path 32 communicate with each other. When the double-headed piston 29 is in the suction stroke state on the first cylinder bore 27 side, the refrigerant in the suction chamber 142 passes through the in-shaft passage 31, the first outlet 312, and the first communication passage 32 to the first cylinder bore 27. It is sucked into the first compression chamber 271.

  When the double-headed piston 29 is in the discharge stroke state on the first cylinder bore 27 side (stroke in which the double-headed piston 29 moves from the right side to the left side in FIG. 1), the communication between the first outlet 312 and the first communication path 32 is blocked. The When the double-headed piston 29 is in the discharge stroke state on the first cylinder bore 27 side, the refrigerant in the first compression chamber 271 pushes the discharge valve 161 away from the discharge port 151 and is discharged into the discharge chamber 131. The refrigerant discharged into the discharge chamber 131 flows out to the external refrigerant circuit 34 through the passage 341.

  When the double-headed piston 29 is in the suction stroke state on the second cylinder bore 28 side (stroke in which the double-headed piston 29 moves from the right side to the left side in FIG. 1), the second outlet 313 and the second communication passage 33 communicate with each other. When the double-headed piston 29 is in the suction stroke state on the second cylinder bore 28 side, the refrigerant in the suction chamber 142 passes through the in-shaft passage 31, the second outlet 313, and the second communication passage 33, and the second cylinder bore 28. 2 is sucked into the compression chamber 281.

  When the double-headed piston 29 is in the discharge stroke state on the second cylinder bore 28 side (stroke in which the double-headed piston 29 moves from the left side to the right side in FIG. 1), the communication between the second outlet 313 and the second communication passage 33 is blocked. The When the double-headed piston 29 is in the discharge stroke state on the second cylinder bore 28 side, the refrigerant in the second compression chamber 281 pushes the discharge valve 191 away from the discharge port 181 and is discharged into the discharge chamber 141. The refrigerant discharged into the discharge chamber 141 flows out to the external refrigerant circuit 34 through the passage 342.

  A heat exchanger 37 for removing heat from the refrigerant, an expansion valve 38, and a heat exchanger 39 for transferring ambient heat to the refrigerant are interposed on the external refrigerant circuit 34. The expansion valve 38 controls the flow rate of the refrigerant according to the change in the gas temperature on the outlet side of the heat exchanger 39. The refrigerant that has flowed into the external refrigerant circuit 34 returns to the suction chamber 142.

  A portion of the seal peripheral surface 211 of the rotary shaft 21 becomes a first rotary valve 35 integrally formed with the rotary shaft 21, and a portion of the seal peripheral surface 212 of the rotary shaft 21 is a second rotary integrally formed with the rotary shaft 21. It becomes the valve 36. The in-shaft passage 31 and the first outlet 312 constitute the first introduction passage 40 of the first rotary valve 35, and the in-shaft passage 31 and the second outlet 313 constitute the second introduction passage 41 of the second rotary valve 36. To do. The second introduction passage 41 overlaps the first introduction passage 40 in the rotating shaft 21 as a part of the first introduction passage 40. The length of the first introduction passage 40 is longer than the length of the second introduction passage 41, and the distance from the suction chamber 142 to the first communication passage 32 via the first introduction passage 40 is the second distance from the suction chamber 142. The distance is longer than the distance from the introduction passage 41 to the second communication passage 33.

  As shown in FIG. 1, the electromagnetic clutch 25 is subjected to excitation / demagnetization control by the control computer C. An air conditioner operation switch W, a room temperature setter S, and a room temperature detector F are signal-connected to the control computer C. When the air conditioner operation switch W is in the ON state, the control computer C uses the electromagnetic clutch 25 based on the temperature difference between the target room temperature set by the room temperature setter S and the detected room temperature detected by the room temperature detector F. Controls current supply (excitation demagnetization) to.

  When the detected temperature is lower than the target temperature, or when the detected temperature is higher than the target temperature and the temperature difference between the detected temperature and the target temperature is less than the tolerance, the control computer C supplies current to the electromagnetic clutch 25. To stop. At this time, the electromagnetic clutch 25 is disengaged and the rotational driving force of the vehicle engine 26 is not transmitted to the rotating shaft 21. When the detected temperature is higher than the target temperature and the temperature difference between the detected temperature and the target temperature exceeds the allowable difference, the control computer C supplies current to the electromagnetic clutch 25. At this time, the electromagnetic clutch 25 is in a connected state, and the rotational driving force of the vehicle engine 26 is transmitted to the rotating shaft 21.

  As shown in FIG. 2 (b), the cross-sectional shape of the first communication path 32 is circular, and as shown in FIG. 2 (c), the cross-sectional shape of the second communication path 33 is circular. The diameter D of the first communication path 32 is larger than the diameter d of the second communication path 33. The cross-sectional shape of the in-axis passage 31 is circular, and the diameter of the in-axis passage 31 is larger than the diameter D of the first communication passage 32.

A curve E in the graph of FIG. 2D shows a change in the temperature in the discharge chamber 131 when the diameter D of the first communication path 32 is changed while the diameter d of the second communication path 33 is constant. Black points on the curve E indicate actual measurement data. The horizontal axis, the flow passage area of the first communication passage 32 and ^{(π × D 2 ÷ 4)} , the ratio of the flow passage area of the second communication passage ^{33 (π × d 2 ÷ 4} ) (π × D 2 ÷ 4 ) / (Π × d ² ÷ 4), and the vertical axis represents the temperature in the discharge chamber 131.

  A curve G in the graph of FIG. 2D is a long hole whose cross-sectional shape is long in the axial direction of the rotating shaft 21 instead of the first communication passage 32 and the second communication passage 33 having a circular cross-sectional shape (for example, patents). The change in the temperature in the discharge chamber 131 when the passage cross-sectional area of the conduction path disclosed in Document 1 is changed is shown.

  In any of the curves E and G, the volume in the compression chambers 271 and 281 is 200 cc, the rotational speed of the double-headed piston compressor 10 is 4500 rpm, and the ratio Pd between the discharge pressure Pd and the suction pressure Ps. / Ps is 12.

  According to the graph of FIG. 2D, if the diameter D of the first communication path 32 is larger than the diameter d of the second communication path 33 and not more than d × 1.8 times, the temperature in the discharge chamber 131 is , It is lower than that of the curve G. If the diameter D in the first communication path 32 is larger than the diameter d in the second communication path 33 and 1.4 times or less, the diameters D and d in the first communication path 32 and the second communication path 33 are the same. The temperature in the discharge chamber 131 is lower than that in the case of the above. When the diameter D of the first communication path 32 is 1.2 times the diameter d of the second communication path 33, the temperature in the discharge chamber 131 is the lowest.

In the first embodiment, the following effects can be obtained.
(1) The distance from the suction chamber 142 to the first compression chamber 271 via the first introduction passage 40 is larger than the distance from the suction chamber 142 to the second compression chamber 281 via the second introduction passage 41. long. Therefore, assuming that the passage cross-sectional area in the first communication passage 32 and the passage cross-sectional area in the second communication passage 33 are the same, the amount of refrigerant supplied to the first compression chamber 271 via the first communication passage 32. Is less than the amount of refrigerant supplied to the second compression chamber 281 via the second communication passage 33. Then, the compression ratio on the first compression chamber 271 side becomes higher than the compression ratio on the second compression chamber 281 side, and the temperature in the discharge chamber 131 becomes higher than the temperature in the discharge chamber 141.

  In the configuration in which the passage diameter (diameter D) in the first communication passage 32 is larger than the passage diameter (diameter d) in the second communication passage 33, the passage cross-sectional area in the first communication passage 32 is the passage break in the second communication passage 33. It becomes larger than the area. This reduces the difference between the amount of refrigerant supplied to the first compression chamber 271 via the first communication passage 32 and the amount of refrigerant supplied to the second compression chamber 281 via the second communication passage 33. To do. Such a reduction in the refrigerant amount difference is effective in suppressing the high temperature of the refrigerant compressed in the first compression chamber 271.

(2) The configuration in which the cross-sectional shapes of the first communication path 32 and the second communication path 33 are circular contributes to easy processing of the first communication path 32 and the second communication path 33.
(3) The configuration in which the passage diameter (diameter D) in the first communication passage 32 is larger than the passage diameter (diameter d) in the second communication passage 33 and not more than 1.8 times is compressed in the first compression chamber 271. It is preferable for suppressing the high temperature of the refrigerant.

  (4) The configuration in which the passage diameter (diameter D) in the first communication passage 32 is larger than the passage diameter (diameter d) in the second communication passage 33 and 1.4 times or less is the first communication passage 32 and the second communication passage 32. Compared to the case where the passage diameters (diameters D and d) in the communication passage 33 are the same, the temperature of the refrigerant compressed in the first compression chamber 271 is lowered.

(5) The configuration in which the diameter D of the first communication path 32 is 1.2 times the diameter d of the second communication path 33 is particularly preferable in order to suppress the high temperature of the refrigerant compressed in the first compression chamber 271. .
(6) The diameters of the circular first communication path 32 and the second communication path 33 are long holes in the axial direction of the rotary shaft 21 and the circumferential width of the communication path having the same path cross-sectional area (the rotary valve Larger than (circumferential direction). Therefore, when the rotary valves 35 and 36 rotate, the timing at which the communication passages 32 and 33 are opened (timing at which the outlets 312 and 313 of the in-shaft passage 31 start to communicate with the communication passages 32 and 33) is a long hole-shaped communication passage. Compared to faster. In addition, the timing at which the communication passages 32 and 33 are closed as the rotary valves 35 and 36 are rotated (the timing at which the outlets 312 and 313 of the in-shaft passage 31 are switched from the state communicating with the communication passages 32 and 33 to the state shut off) is long. It is slower than the hole-shaped communication path. Therefore, the configuration in which the cross-sectional shape of the first communication path 32 and the second communication path 33 is circular has a preferable result that the refrigerant supply to the compression chambers 271 and 281 is larger than that of the long hole-shaped communication path. Bring.

  (7) The longer the axial lengths Z1 and Z2 (shown in FIG. 1) of the rotary shaft 21 in the communication paths 32 and 33, the longer the lengths x and y of the heads 291 and 292 of the double-headed piston 29 (rotary shaft 21). It is necessary to lengthen the length in the axial direction (shown in FIG. 1). As the lengths x and y of the heads 291 and 292 become longer, the double-headed piston 29 becomes heavier.

  The diameters of the circular first communication path 32 and the second communication path 33 are long and long in the axial direction of the rotating shaft 21 and are smaller than the axial length of the communication path having the same path cross-sectional area. Therefore, the configuration in which the cross-sectional shape of the first communication path 32 and the second communication path 33 is circular is preferable in that the lengths x and y of the head portions 291 and 292 are shorter than the long hole-shaped communication path. Bring results.

  (8) Since the cross-sectional shape of the communication passages 32 and 33 is circular, the axial lengths Z1 and Z2 of the rotary shaft 21 can be made shorter than that of the long hole-shaped communication passage. 29, the timing at which the end face of 29 passes through the communication passages 32, 33 is earlier, that is, in the configuration in which the cross-sectional shape of the communication passages 32, 33 is circular, the timing when the double-headed piston 29 fully opens the communication passages 32, 33 Can be made faster than in the case of the long hole-shaped communication path, and the amount of refrigerant supplied is increased.

In the present invention, the following embodiments are also possible.
A suction chamber may be provided in the front housing 13, and the refrigerant may be introduced from the suction chamber into the compression chambers 271 and 281 via the in-shaft passage 31.

A refrigerant may be introduced from the suction pressure region outside the compressor into the first and second introduction passages.
The first rotary valve 35 and the second rotary valve 36 may be formed separately from the rotary shaft 21.

The technical idea that can be grasped from the embodiment described above will be described below.
[1] The refrigerant suction structure in a double-headed piston compressor according to any one of claims 1 to 3, wherein the suction pressure region is a suction chamber in the compressor.

  [2] The first introduction passage includes an in-shaft passage in the rotating shaft and a first outlet of the in-shaft passage, and the second introduction passage includes the in-shaft passage and the in-shaft passage. The refrigerant suction structure in a double-headed piston compressor according to any one of claims 1 to 3 and [1], wherein the refrigerant suction structure is configured by a second outlet of the passage.

  [3] The refrigerant suction structure in the double-headed piston compressor according to [2], wherein a passage cross-sectional area in the in-shaft passage is larger than a passage cross-sectional area in the second communication passage.

The sectional side view of the whole compressor which shows one Embodiment. (A) is a partial expanded side sectional view. FIG. 2B is an enlarged cross-sectional view taken along the line C-C in FIG. (C) is the DD sectional expanded sectional view of Fig.2 (a). (D) is a graph. (A) is the sectional view on the AA line of FIG. (B) is the BB sectional drawing of FIG.

Explanation of symbols

  10: Double-head piston compressor. 11, 12 ... Cylinder block. 131, 141: Discharge chamber as a discharge pressure region. 14: Rear housing. 142: A suction chamber as a suction pressure region in the compressor. 21 ... Rotating shaft. 27: First cylinder bore. 271: First compression chamber. 28: Second cylinder bore. 281 ... Second compression chamber. 29 ... Double-headed piston. 31: An in-axis passage constituting the first introduction passage and the second introduction passage. 312: a first outlet constituting a first introduction passage. 313: a second outlet constituting the second introduction passage. 32 ... 1st communicating path. 33: Second communication path. 35: First rotary valve. 36: Second rotary valve. 40: First introduction passage. 41 ... Second introduction passage. D, d: Diameter as a passage diameter.

Claims (3)

A double-headed piston interlocking with the rotation of the rotating shaft is accommodated in a pair of first and second cylinder bores, and introduces refrigerant from a suction pressure region into a first compression chamber defined in the first cylinder bore. A first rotary valve having a first introduction passage and a second rotary valve having a second introduction passage for introducing refrigerant from the suction pressure region into a second compression chamber defined in the second cylinder bore. A first communication passage that communicates with the first compression chamber and communicates with the first introduction passage; and a second communication that communicates with the second compression chamber and communicates with the second introduction passage. A passage is provided in the cylinder block, and at least a part of the first introduction passage and the second introduction passage is provided in the rotating shaft, and the second introduction passage is a part of the first introduction passage. Said times as part Overlap with the first introduction passage in the axial distance of the first introduction passage, the refrigerant suction structure of a long double-headed piston type compressor than the distance of the second introduction passage,
The cross-sectional shape of the first communication path and the second communication path is circular, and the diameter of the passage in the first communication path is larger than the diameter of the passage in the second communication path. Inhalation structure.   2. The refrigerant suction structure in a double-headed piston compressor according to claim 1, wherein a passage diameter in the first communication passage is 1.8 times or less of a passage diameter in the second communication passage.   2. The refrigerant suction structure in a double-headed piston compressor according to claim 1, wherein a passage diameter in the first communication passage is 1.4 times or less than a passage diameter in the second communication passage.

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