The present invention relates to a double-headed piston type compressor.
As a compressor for a vehicle air conditioning system, a double-headed piston type compressor as disclosed in, for example, Patent Document 1 has been proposed. The cylinder block of this type of compressor includes cylinder bores for accommodating double-headed pistons. A swash plate, which operates together with a rotary shaft, causes the double-headed pistons to reciprocate in the cylinder bores. The double-headed piston type compressor includes compression chambers defined in each cylinder bore on both ends of the associated double-headed piston. Each double-headed piston compresses refrigerant drawn into the associated compression chambers, and discharges the compressed refrigerant to the outside of the compression chambers. Patent Document 1 discloses a compressor in which rotary valves are employed as a mechanism for drawing in refrigerant into the compression chambers, and a compressor in which suction valves are employed as a mechanism for drawing refrigerant into the compression chambers.
In these days, engines are made quieter to reduce noise in compartments of vehicles (in particular, automobiles). Thus, there is a demand for quieter compressors used in vehicle air conditioning systems. However, in the conventional compressor disclosed in Patent Document 1, noise and vibration are generated due to pulsation (pressure fluctuation) caused in the compressor. These noise and vibration are transmitted from the compressor to the passenger compartment through conduits, thereby generating noise in the passenger compartment. Thus, in the conventional compressor, sufficient measures are hardly taken to reduce noise to a desired level.
Accordingly, it is an objective of the present invention to provide a quiet double-headed piston type compressor that has a reduced pulsation thereby suppressing noise.
The present invention provides a double-headed piston type compressor including a front housing member, a rear housing member, and a cylinder block located between the front housing member and the rear housing member. The cylinder block includes cylinder bores. The front housing member, the rear housing member, and the cylinder block define a swash plate chamber. The compressor defines a suction pressure zone. Each of double-headed pistons is slidably inserted in one of the cylinder bores. Each double-headed piston defines a compression chamber close to the front housing member and a compression chamber close to the rear housing member. One of the compression chambers serves as a first compression chamber and the other one of the compression chambers serves as a second compression chamber. The compressor includes a rotary shaft rotatably supported in the cylinder block and a swash plate, which rotates with the rotary shaft in the swash plate chamber. The swash plate causes the double-headed pistons to reciprocate in the cylinder bores. As a result, refrigerant is drawn into the compression chambers from the suction pressure zone and is compressed in and discharged from the compression chambers. A mechanism for drawing in the refrigerant to the first compression chambers is configured by a rotary valve, which includes an introduction passage for introducing the refrigerant from the suction pressure zone to the first compression chambers. A mechanism for drawing the refrigerant into the second compression chambers is configured by suction valves, which selectively open and close in accordance with the difference between the pressure in the suction pressure zone and the pressure in the second compression chambers.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
A first embodiment of the present invention will now be described with reference to
As shown in
A front discharge chamber 13a and a front suction chamber 13b are defined in the front housing member 13. The front suction chamber 13b is connected to each bolt insertion hole BH via a communication passage R1 formed in the front housing member 13. Also, a rear discharge chamber 14a and a rear suction chamber 14b are defined in the rear housing member 14.
A suction hole P is formed in the outer circumferential surface of the front cylinder block 11 and extends to the inner circumferential surface of the front cylinder block 11. The suction hole P is connected to an external refrigerant circuit provided outside of the compressor 10. A discharge hole, which is not shown, is formed in the outer circumferential surface of the front cylinder block 11 and extends to the inner circumferential surface of the front cylinder block 11. The discharge hole is connected to the external refrigerant circuit.
When the compressor 10 is used to configure a refrigerant circuit of a vehicle air conditioning system, the external refrigerant circuit connects a discharge pressure zone of the compressor 10 to a suction pressure zone of the compressor 10. The external refrigerant circuit includes a condenser, an expansion valve, and an evaporator. The condenser, the expansion valve, and the evaporator are arranged in this order in the external refrigerant circuit from the discharge pressure zone of the compressor 10.
A front valve plate 15, a discharge flap plate 16, a front retainer plate 17, and a suction flap plate 18 are arranged between the front housing member 13 and the front cylinder block 11. The front valve plate 15 includes front discharge ports 15a formed at positions corresponding to the front discharge chamber 13a, and front suction ports 15b formed at positions corresponding to the front suction chamber 13b. Also, the discharge flap plate 16 includes front discharge valves 16a formed at positions corresponding to the front discharge ports 15a. The front discharge valves 16a, which are flap valves, selectively open and close the front discharge ports 15a. The valve dimension of the front discharge valves 16a formed in the discharge flap plate 16 is set to a dimension X. The valve dimension refers to the dimension from the proximal end of each front discharge valve 16a, which is held by a partition wall defining the front discharge chamber 13a in the front housing member 13, to the distal end of the front discharge valve 16a. Front discharge retainers 17a, which restrict the opening degree of the front discharge valves 16a, are formed on the front retainer plate 17. Also, the suction flap plate 18 has flap valves 18a, which are formed at positions corresponding to the front suction ports 15b. The flap valves 18a selectively open and close the front suction ports 15b. The front cylinder block 11 has notches 11c, which are formed to correspond to the flap valves 18a. The wall of each notch 11c functions as a front suction retainer, which restricts the opening degree of the associated flap valve 18a.
A valve plate 19, a discharge flap plate 20, and a retainer plate 21 are arranged between the rear housing member 14 and the rear cylinder block 12. Discharge ports 19a are formed in the valve plate 19 at positions corresponding to the discharge chamber 14a. Also, rear discharge valves 20a are formed in the discharge flap plate 20 at positions corresponding to the discharge ports 19a. The rear discharge valves 20a, which are flap valves, selectively open and close the discharge ports 19a. The dimension of the rear discharge valves 20a formed in the discharge flap plate 20 is set to a dimension X. The valve dimension refers to a dimension from the proximal end of each rear discharge valve 20a, which is held by a partition wall defining the discharge chamber 14a in the rear housing member 14, to the distal end of the rear discharge valve 20a. In the first embodiment, the valve dimension (dimension X) of the front discharge valves 16a is equal to the valve dimension (dimension X) of the rear discharge valves 20a. That is, the discharge flap plates 16, 20 have the same structure and include the discharge valves 16a, 20a having the same dimension, respectively. Also, retainers 21a, which restrict the opening degree of the rear discharge valves 20a, are formed on the retainer plate 21.
The cylinder blocks 11, 12 rotatably support a rotary shaft 22. The rotary shaft 22 is inserted in shaft holes 11a, 12a, which extend through the cylinder blocks 11, 12. The rotary shaft 22 is also inserted in a through hole 15c, which is formed at the center of the front valve plate 15. The outer circumferential surface of the rotary shaft 22 and the inner circumferential surface of the through hole 15c configure a sliding portion of the rotary shaft 22. The rotary shaft 22 is directly supported by the cylinder blocks 11, 12 via the shaft holes 11a, 12a. A lip-seal-type shaft sealing assembly 23 is arranged between the front housing member 13 and the rotary shaft 22. The shaft sealing assembly 23 is accommodated in a seal chamber 13c, which if formed in the front housing member 13. The front discharge chamber 13a and the front suction chamber 13b are located around the seal chamber 13c.
A swash plate 24 is secured to the rotary shaft 22 and operates together with the rotary shaft 22. The swash plate 24 is located in a swash plate chamber 25, which is defined between the cylinder blocks 11, 12. A thrust bearing 26 is arranged between the end surface of the front cylinder block 11 and an annular proximal portion 24a of the swash plate 24. A thrust bearing 27 is arranged between the end surface of the rear cylinder block 12 and the proximal portion 24a of the swash plate 24. The thrust bearings 26, 27 sandwich the swash plate 24 and restrict the movement of the swash plate 24 along the axis L of the rotary shaft 22.
Front cylinder bores 28 (five in the first embodiment, only one of the front cylinder bores 28 is shown in
The swash plate 24 coacts with the rotary shaft 22 and rotates integrally with the rotary shaft 22. The rotation of the swash plate 24 is transmitted to the double-headed pistons 30 through pairs of shoes 31, which sandwich the swash plate 24. As a result, each double-headed piston 30 reciprocates back and forth in the associated cylinder bores 28, 29. In each pair of the cylinder bores 28, 29, the associated double-headed piston 30 defines a first compression chamber, which is a front compression chamber 28a in the first embodiment, and a second compression chamber, which is a rear compression chamber 29a in the first embodiment. Sealing circumferential surfaces 11b, 12b are formed on the inner circumferential surfaces of the shaft holes 11a, 12a through which the rotary shaft 22 is inserted. The rotary shaft 22 is directly supported by the cylinder blocks 11, 12 at the sealing circumferential surfaces 11b, 12b. In the first embodiment, the suction hole P and the bolt insertion holes BH are open to the swash plate chamber 25 of the compressor 10.
An introduction passage, which is a supply passage 22a in the first embodiment, is formed in the rotary shaft 22. The supply passage 22a is a bore-like passage bored in the end surface of the rotary shaft 22 that is closer to the rear housing member 14. The rotary shaft 22 is a solid shaft. Thus, one end of the supply passage 22a is open to the rear suction chamber 14b of the rear housing member 14. Also, a communication passage 32 is formed in the rotary shaft 22 at a position corresponding to the rear cylinder block 12 to be connected to the supply passage 22a. The opening of the communication passage 32 at the outer circumferential surface of the rotary shaft 22 functions as an outlet 32b of the communication passage 32. Also, suction passages 33 (five in the first embodiment, only one of the suction passages 33 is shown in
In the compressor 10 according to the first embodiment, the mechanism for drawing in refrigerant (gas) to the front compression chambers 28a differs from the mechanism for drawing in refrigerant to the rear compression chambers 29a. More specifically, the mechanism for drawing in refrigerant to the front compression chambers 28a includes the flap valves 18a located between the front suction chamber 13b and the front compression chambers 28a. Each flap valve 18a selectively opens and closes in accordance with the difference between the pressure in the front suction chamber 13b and the pressure in the associated front compression chamber 28a. The mechanism for drawing in refrigerant to the rear compression chambers 29a includes the rotary valve 35, which is located between the rear suction chamber 14b and the rear compression chambers 29a. The rotary valve 35 includes the supply passage 22a, which introduces refrigerant (gas) in the front suction chamber 13b to the rear compression chambers 29a.
The compression chambers into which refrigerant is drawn in by the rotary valve 35 are referred to as first compression chambers, and the compression chambers into which refrigerant is drawn in by the flap valves 18a are referred to as second compression chambers. In the first embodiment, the front compression chambers 28a are the second compression chambers, and the rear compression chambers 29a are the first compression chambers. According to the compressor 10 configured as described above, when a suction stroke takes place in each front cylinder bore 28, that is, when each double-headed piston 30 moves from the left side to the right side in
When a discharge stroke takes place in each front cylinder bore 28, that is, when each double-headed piston 30 moves from the right side to the left side in
When a suction stroke takes place in each rear cylinder bore 29, that is, when each double-headed piston 30 moves from the right side to the left side in
When a discharge stroke takes place in each rear cylinder bore 29, that is, when each double-headed piston 30 moves from the left side to the right side in
The operation of the compressor 10 according to the first embodiment will now be described with reference to
Measurement was carried out on two types of experimental apparatuses of a refrigerant circuit including a double-headed piston type compressor and an external connect circuitry.
As apparent from the measurement result in
In the compressor 10 of the first embodiment, the mechanism for drawing in refrigerant to the front compression chambers 28a is configured by the flap valves 18a, and the mechanism for drawing in refrigerant to the rear compression chambers 29a is configured by the rotary valve 35. The flap valves 18a and the rotary valve 35 behave (move) differently when drawing in refrigerant due to the structural difference. That is, since the flap valves 18a are selectively opened and closed by the pressure difference, a delay occurs in opening and closing the flap valves 18a when drawing in refrigerant to the front compression chambers 28a. In contrast, the rotary valve 35 is provided on the rotary shaft 22 and operates together with the rotary shaft 22. Thus, when drawing in refrigerant to the rear compression chambers 29a, refrigerant is forcibly drawn into each rear compression chamber 29a when the supply passage 22a (communication passage 32) is connected to the rear compression chamber 29a. Due to such difference in the behavior, a phase difference occurs between the time at which refrigerant is drawn into each of the front compression chambers 28a, and the time at which refrigerant is drawn into each of the rear compression chambers 29a. Therefore, the amount of refrigerant drawn into the front compression chambers 28a is less than the amount of refrigerant drawn into the rear compression chambers 29a.
That is, the density of the refrigerant in the front compression chambers 28a after the suction stroke is less than that in the rear compression chambers 29a after the suction stroke. Thus, when shifting from the suction stroke to the discharge stroke, a phase difference occurs between the time at which refrigerant is discharged from each of the front compression chambers 28a and the time at which refrigerant is discharged from each of the rear compression chambers 29a. That is, a phase difference occurs between the time at which refrigerant is discharged from each of the front compression chambers 28a to the front discharge chamber 13a and the time at which refrigerant is discharged from each of the rear compression chambers 29a to the rear discharge chamber 14a. The time at which refrigerant is discharged from each of the front compression chambers 28a to the front discharge chamber 13a is later than the time at which refrigerant is discharged from each of the rear compression chambers 29a to the rear discharge chamber 14a. As a result, according to the compressor 10 of the first embodiment, the peak value of the pulsation waveform at a specific degree does not become extremely high, and the peak value is reduced. That is, discharge pulsation of the compressor 10 is reduced.
For example, cases will be discussed below in which the mechanism for drawing in refrigerant to the front compression chambers 28a and the mechanism for drawing in refrigerant to the rear compression chambers 29a are both configured by the flap valves or the rotary valves. In these cases, the mechanism for drawing in refrigerant to the front compression chambers 28a and the mechanism for drawing in refrigerant to the rear compression chambers 29a show the same behavior (motion) when drawing in refrigerant. Thus, a phase difference does not occur between the time at which refrigerant is drawn into the front compression chambers 28a and the time at which refrigerant is drawn into the rear compression chambers 29a. Since there is no difference between the density of refrigerant in the front compression chambers 28a and the density of refrigerant in the rear compression chambers 29a, no difference occurs between the time at which refrigerant is discharged from the front compression chambers 28a and the time at which refrigerant is discharged from the rear compression chambers 29a. In this manner, when the mechanism for drawing in refrigerant to the front compression chambers 28a is the same as the mechanism for drawing in refrigerant to the rear compression chambers 29a, the discharge pulsation at a specific degree always occurs in a concentrated manner, thereby increasing the peak value of the pulsation waveform. As a result, the noise caused by vibration might raise a problem.
The first embodiment has the following advantages.
(1) The mechanism for drawing in refrigerant to the front compression chambers 28a differs from the mechanism for drawing in refrigerant to the rear compression chambers 29a. In the first embodiment, the refrigerant suction mechanism close to the front compression chambers 28a is configured by the flap valves 18a, and the refrigerant suction mechanism close to the rear compression chambers 29a is configured by the rotary valve 35. This reduces the suction pulsation in the compressor 10. Accordingly, the pulsation of the compressor 10 is reduced, thereby suppressing generation of noise. Thus, the quiet compressor 10 is achieved.
(2) The suction hole P, which is connected to the external refrigerant circuit, is provided in the cylinder block 11. That is, refrigerant is supplied to the front compression chambers 28a and the rear compression chambers 29a via the swash plate chamber 25. Therefore, the refrigerant is distributed from the center of the compressor 10 to the front compression chambers 28a and the rear compression chambers 29a. This suppresses decrease in the suction efficiency. That is, the suction efficiency is prevented from being reduced in either of the compression chambers 28a, 29a.
(3) The supply passage 22a of the rotary valve 35 is a bore-like passage that opens in the end of the rotary shaft 22. Thus, refrigerant is supplied to the rotary valve 35 via the opening end of the rotary shaft 22, which increases the refrigerant suction efficiency. That is, since the supply passage 22a is always connected to the rear suction chamber 14b and is always rotated at a fixed position, refrigerant is easily supplied.
(4) The rotary valve 35 having the bore-like passage is provided close to the rear housing member 14. If, for example, the bore-like passage is provided in the rotary shaft 22 and the rotary valve is provided close to the front housing member 13, the bore-like passage must be provided in the rotary shaft 22 extending from the rear housing member 14 to the front housing member 13. This reduces the strength of the rotary shaft 22. In contrast, in the case where the rotary valve 35, which has the bore-like passage, is provided close to the rear housing member 14 as in the first embodiment, the bore-like passage is provided only in part of the rotary shaft 22 close to the rear housing member 14. Thus, the first embodiment suppresses decrease in the strength of the rotary shaft 22. That is, the first embodiment is advantageous in securing the strength of the rotary shaft 22 and facilitates machining of the rotary shaft 22.
(5) The rotary valve 35 is provided close to the rear housing member 14. Thus, as compared to a case where, for example, a rotary valve is provided close to the front housing member 13, which is provided with the shaft sealing assembly 23 and thus lacks in space, the first embodiment allows a passage for drawing refrigerant to the rotary valve to be easily created. In the first embodiment, the supply passage 22a functions as the passage for drawing in refrigerant to the rotary valve 35.
Providing the rotary valve 35 close to the rear housing member 14 is also advantageous in view of load as compared to a case where the rotary valve is provided close to the front housing member 13, which receives a great load such as torsion and bend. That is, the case where the rotary valve 35 is provided close to the front housing member 13 has a greater possibility of causing slight deformation in the rotary valve (35) and the cylinder blocks (11, 12) due to adverse effect of the load as compared to the case where the rotary valve 35 is provided close to the rear housing member 14. The deformation might cause a gap between the rotary valve (35) and the cylinder blocks (11, 12). Furthermore, the deformation might cause refrigerant to leak from between the suction passages (33), which connect the cylinder bores (28, 29) to the shaft holes (11a, 12a). As a result, the suction efficiency of the rotary valve (35) might be reduced, which might reduce the efficiency of the compressor. Thus, the first embodiment in which the rotary valve 35 is provided close to the rear housing member 14 suppresses deformation of the rotary valve 35 and the rear cylinder block 12. As a result, reduction in the suction efficiency of the rotary valve 35 is suppressed, which further suppresses the reduction in the efficiency of the compressor.
(6) Furthermore, the rotary valve 35 is provided close to the rear housing member 14, and the rear suction chamber 14b, which is always connected to the rotary valve 35, is formed in the rear housing member 14. Thus, refrigerant can be temporarily stored in the rear suction chamber 14b. That is, refrigerant is easily drawn into the rotary valve 35.
(7) The valve dimension of the front discharge valves 16a is set equal to the valve dimension of the rear discharge valves 20a. Thus, the discharge structures on both ends of the compressor 10 have the same structure, which suppresses increase in the manufacturing costs.
A second embodiment of the present invention will now be described with reference to
As shown in
The second embodiment has the following advantages in addition to the advantages (1) to (6) of the first embodiment.
(8) The valve dimension of the front discharge valves 16a for discharging the refrigerant drawn in through the flap valves 18a differs from the valve dimension of the rear discharge valves 20a for discharging the refrigerant drawn in through the rotary valve 35. Thus, when discharging refrigerant from each of the front compression chambers 28a and each of the rear compression chambers 29a, the discharge valves 16a, 20a behave differently, and a phase difference is generated between the times at which refrigerant is discharged. This further reduces the discharge pulsation of the compressor 10.
A third embodiment of the present invention will now be described with reference to
Like the compressor 10 of the first and second embodiments, in the compressor 10 according to the third embodiment, the mechanism for drawing in refrigerant to the front compression chambers 28a is configured by the flap valves 18a, and the mechanism for drawing in refrigerant to the rear compression chambers 29a is configured by the rotary valve 35. The third embodiment differs from the first and second embodiments in the structure of a passage for supplying refrigerant to the rear compression chambers 29a via the rotary valve 35. The structure of the passage according to the third embodiment will mainly be discussed below.
An introduction passage, which is a supply passage 22b in the third embodiment, is formed in the rotary shaft 22. The supply passage 22b of the third embodiment includes a bore-like passage section 36 and a groove-like passage section 37, which is provided next to the bore-like passage section 36. The bore-like passage section 36 is formed by boring the end face of the rotary shaft 22, which is a solid shaft. The groove-like passage section 37 is formed by machining a groove on the outer circumferential surface of the rotary shaft 22. Furthermore, a communication passage R3 is formed in the rear cylinder block 12 to connect the swash plate chamber 25 to the shaft hole 12a. The groove-like passage section 37 is formed to connect each of the suction passages 33 in the rear cylinder block 12 to the communication passage R3.
In the compressor 10 configured as described above, when a suction stroke takes place in each rear cylinder bore 29, that is, when each double-headed piston 30 moves from the right side to the left side in
When a discharge stroke takes place in each rear cylinder bore 29, that is, when each double-headed piston 30 moves from the left side to the right side in
Therefore, the third embodiment has the following advantages in addition to the advantages (1), (2), (5), (6) of the first embodiment and the advantage (8) of the second embodiment.
(9) The supply passage 22b of the rotary valve 35 is formed by the combination of the bore-like passage section 36 and the groove-like passage section 37. Thus, the volume of refrigerant drawn into the rotary valve 35 is increased.
A fourth embodiment of the present invention will now be described with reference to
In the compressor 10 of the fourth embodiment, the mechanism for drawing in refrigerant to the front compression chambers 28a is configured by a rotary valve 49, and the mechanism for drawing in refrigerant to the rear compression chambers 29a is configured by flap valves 46a. That is, the positions of the two refrigerant suction mechanisms of the compressor 10 according to the fourth embodiment are reversed with respect to those in the first to third embodiments.
In other words, the compression chambers into which refrigerant is drawn in by the rotary valve 49 are referred to as the first compression chambers, and the compression chambers into which refrigerant is drawn in by the flap valves 46a are referred to as the second compression chambers. In the fourth embodiment, the front compression chambers 28a are the first compression chambers, and the rear compression chambers 29a are the second compression chambers.
In the fourth embodiment, the front housing member 13 includes only the front discharge chamber 13a, and the front suction chamber 13b is omitted. The rear housing member 14 includes the rear discharge chamber 14a and the rear suction chamber 14b. A valve plate 40, a discharge flap plate 41, and a retainer plate 42 are arranged between the front housing member 13 and the front cylinder block 11. Front discharge ports 40a are formed in the valve plate 40 at positions corresponding to the front discharge chamber 13a. Also, front discharge valves 41a are formed in the discharge flap plate 41 at positions corresponding to the front discharge ports 40a. Retainers 42a, which restrict the opening degree of the front discharge valves 41a, are formed in the retainer plate 42.
A valve plate 43, a discharge flap plate 44, a retainer plate 45, and a suction flap plate 46 are arranged between the rear housing member 14 and the rear cylinder block 12. The valve plate 43 includes rear discharge ports 43a, which are formed at positions corresponding to the rear discharge chamber 14a, and rear suction ports 43b, which are formed at positions corresponding to the rear suction chamber 14b. The discharge flap plate 44 includes rear discharge valves 44a, which are formed at positions corresponding to the rear discharge ports 43a. In the fourth embodiment, the valve dimension c of the front discharge valves 41a is set greater than the valve dimension d of the rear discharge valves 44a (c>d). The retainer plate 45 includes retainers 45a, which restrict the opening degree of the rear discharge valves 44a. The suction flap plate 46 includes the flap valves 46a, which are formed at positions corresponding to the rear suction ports 43b. The flap valves 46a selectively open and close the rear suction ports 43b. The rear cylinder block 12 includes notches 12c formed to correspond to the flap valves 46a. The wall surface of each notch 12c functions as a rear suction retainer, which restricts the opening degree of the associated flap valve 46a.
The rotary shaft 22 includes an introduction passage, which is a supply passage 47 in the fourth embodiment. The supply passage 47 of the fourth embodiment is a groove-like passage formed by machining a groove in the outer circumferential surface of the rotary shaft 22, which is a solid shaft. One end of the supply passage 47 is open to the seal chamber 13c, which accommodates the shaft sealing assembly 23. Also, suction passages 48 (five in this embodiment, only one of the suction passages 48 is shown in
Furthermore, a communication passage 50 is formed through the front housing member 13 and the front cylinder block 11. The communication passage 50 is located at a lower section of the cylinder block 11, and extends between two adjacent cylinder bores 28, 29. An inlet 50a of the communication passage 50 is open to the swash plate chamber 25, and an outlet 50b of the communication passage 50 is open to the seal chamber 13c. That is, the communication passage 50 connects the seal chamber 13c to the swash plate chamber 25. Communication passages R4 are also formed in the rear housing member 14 to connect the rear suction chamber 14b to the bolt insertion holes BH.
In the compressor 10 configured as described above, when a suction stroke takes place in each front cylinder bore 28, that is, when each double-headed piston 30 moves from the left side to the right side in
When a discharge stroke takes place in each front cylinder bore 28, that is, when each double-headed piston 30 moves from the right side to the left side in
When a suction stroke takes place in each rear cylinder bore 29, that is, when each double-headed piston 30 moves from the right side to the left side in
When a discharge stroke takes place in each rear cylinder bore 29, that is, when each double-headed piston 30 moves from the left side to the right side in
The two refrigerant suction mechanisms of the compressor 10 according to the fourth embodiment include the flap valves 46a and the rotary valve 49. Thus, in the fourth embodiment also, the same operations as that of the first to third embodiments are obtained. That is, although the arrangement of the flap valves 46a and the rotary valve 49 in the compressor 10 of the fourth embodiment is reversed with respect to that of the first to third embodiments, the same operations are obtained.
Therefore, the fourth embodiment has the following advantages in addition to the advantages (1) and (2) of the first embodiment and the advantage (8) of the second embodiment.
(10) The supply passage 47 of the rotary valve 49 is the groove-like passage. Thus, compared to a case where a bore-like passage is formed by boring the rotary shaft 22, the manufacturing costs of the rotary shaft 22 are reduced.
(11) The refrigerant in the swash plate chamber 25 is supplied to the rotary valve 49 via the seal chamber 13c of the shaft sealing assembly 23. Thus, the shaft sealing assembly 23 is cooled by the refrigerant. This extends the life of the shaft sealing assembly 23, and prevents change in the property of the lubricant of the shaft sealing assembly 23.
A fifth embodiment of the present invention will now be described with reference to
Like the compressor 10 according to the fourth embodiment, in the compressor 10 of the fifth embodiment, the mechanism for drawing in refrigerant to the front compression chambers 28a is configured by the rotary valve 49 and the mechanism for drawing in refrigerant to the rear compression chambers 29a is configured by the flap valves 46a. According to the fifth embodiment, the structure of the passage for supplying refrigerant to the front compression chambers 28a via the rotary valve 49 differs from that of the fourth embodiment.
As shown in
In the compressor 10 configured as described above, when a suction stroke takes place in each front cylinder bore 28, that is, when each double-headed piston 30 moves from the left side to the right side in
When a discharge stroke takes place in each front cylinder bore 28, that is, when each double-headed piston 30 moves from the right side to the left side in
The above embodiments may be modified as follows.
In each of the embodiments, the structure of the passage of the rotary valves 35, 49 may be changed. For example, in a case where the rotary valves 35, 49 have the bore-like passage, the diameter and the length of the bore-like passage may be changed. In a case where the rotary valves 35, 49 have the groove-like passage, the depth and the length of the groove may be changed. Furthermore, for example, in the third embodiment shown in
In the second to fifth embodiments, the valve dimension of the discharge valves 16a, 20a, 41a, 44a, which are flap valves provided in the discharge chambers 13a, 14a, may be the same.
In each of the embodiments, in a case where the refrigerant suction mechanism is configured by the flap valves 18a, 46a, the arrangement of the discharge chambers 13a, 14a and the suction chambers 13b, 14b provided in the front housing member 13 or the rear housing member 14 may be changed.
In each of the embodiments, the arrangement of the suction hole P connected to the external refrigerant circuit may be changed. For example, the suction hole P may be formed in the rear housing member 14.
In each of the embodiments, a path for supplying refrigerant from the suction hole P, which is connected to the external refrigerant circuit, may be changed. For example, in each of the embodiments, the bolt insertion holes BH are used to supply refrigerant to the suction chambers 13b, 14b. However, a supply passage separate from the bolt insertion holes BH may be provided in the cylinder blocks 11, 12.
The above embodiments are embodied in the ten cylinder compressor 10, but the number of the cylinders may be changed.
As shown in
In each of the embodiments, a residual refrigerant bypass groove may be formed in the outer surface of the rotary shaft 22 on which the rotary valve 35 or 49 is formed. The residual refrigerant bypass groove forms a passage that collects refrigerant remained in each compression chamber at the end of a discharge stroke, and supplies the collected refrigerant to the compression chamber at the end of a suction stroke. That is, the residual refrigerant bypass groove is formed to connect the compression chamber (cylinder bore) at the end of the discharge stroke to the compression chamber (cylinder bore) at the end of the suction stroke. Thus, when the compression chamber at the end of the discharge stroke is shifted to the suction stroke again, refrigerant remained in the compression chamber is suppressed from expanding again, and refrigerant is reliably drawn into the compression chamber.
The technical ideas obtainable from the above embodiments other than those disclosed in the claim section are described below with their advantages.
(1) The refrigerant compressed in the compression chambers in the front housing member is discharged to the discharge pressure zone by the discharge valves located between the compression chambers and the front housing member, and the refrigerant compressed in the compression chambers in the rear housing member is discharged to the discharge pressure zone by the discharge valves located between the compression chambers and the rear housing member, wherein the valve dimension of the discharge valves of the first compression chambers is greater than the valve dimension of the discharge valves of the second compression chambers.
Number | Date | Country | Kind |
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2005-302354 | Oct 2005 | JP | national |
2006-281667 | Oct 2006 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2006/320612 | 10/17/2006 | WO | 00 | 12/17/2007 |