JP2009079503A - Variable displacement compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve durability of a variable displacement compressor 1 by suppressing rapid pressure rise in a crank chamber 15 when a piston 27 is changed over to a de-stroke state even when a differential pressure valve 55 is used in the variable displacement compressor 1. <P>SOLUTION: The differential pressure valve 55 controlling flow rate of gas supplied to the crank chamber 15 from a delivery chamber 19 to set differential pressure Pd-Ps of pressure Pd at delivery chamber 19 side and pressure Ps at a suction chamber 17 side is provided in a middle of a charging passage 53 keeping communication between the crank chamber 15 and the delivery chamber 19. A pressure control valve 63 provided with a valve element 65 for a pressure control valve constructed to get in a full close state when pressure Pd at the delivery chamber 19 side exceeds set pressure is provided between the crank chamber 15 and the differential pressure valve 55 in the charging passage 53. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a variable capacity compressor used in, for example, a vehicle air conditioner.

In recent years, various developments have been made on variable capacity compressors, and there is one disclosed in Patent Document 1 as a prior art of a variable capacity compressor.
That is, the compressor according to the prior art compresses refrigerant gas (an example of a gas) and includes a housing, and the housing has a cylinder bore therein. Further, the housing has a crank chamber on the front side of the cylinder bore in the interior, and has a suction chamber and a discharge chamber in communication with the cylinder bore on the rear side of the cylinder bore in the interior.

  A drive shaft extending in the front-rear direction is rotatably provided in the housing, and a front end portion of the drive shaft is coupled to an engine (an example of an external drive source) via a pulley, a timing belt, and the like. is there. Also, a single-headed piston is provided in the cylinder bore so as to be able to reciprocate, and a motion conversion mechanism for converting the rotational motion of the drive shaft into the reciprocating motion of the piston is disposed in the crank chamber.

  Inside the housing, an extraction passage that always communicates the crank chamber and the suction chamber and an air supply passage that communicates the crank chamber and the discharge chamber are formed. In addition, a flow rate control valve is disposed in the middle of the air supply passage, and this flow rate control valve controls the refrigerant gas supplied from the discharge chamber to the crank chamber in accordance with the pressure on the suction chamber side (suction pressure). The flow rate is controlled. The flow control valve includes a bellows that expands and contracts according to the pressure on the suction chamber side and a valve body for a flow control valve that opens and closes by the expansion and contraction of the bellows.

  Therefore, by rotating the drive shaft by driving the engine, the motion conversion mechanism can convert the rotational motion of the drive shaft into the reciprocating motion of the piston. In other words, the piston is reciprocated in conjunction with the rotation of the drive shaft. Can be moved. Thereby, the refrigerant gas sucked from the suction chamber can be compressed in the cylinder bore, and the compressed refrigerant gas can be discharged from the cylinder bore to the discharge chamber.

  In addition, when the variable capacity compressor is in operation, when the cooling load is large (in other words, when the pressure on the suction chamber side is high), the opening degree of the valve body for the flow control valve is reduced by shortening the bellows. The flow rate of the refrigerant gas supplied from the discharge chamber to the crank chamber via the air supply passage is reduced, and the pressure in the crank chamber is reduced. As a result, the differential pressure between the pressure on the front surface side of the piston and the pressure on the rear surface side of the piston is reduced, and the stroke of the piston can be increased to increase the discharge capacity of the refrigerant gas.

On the other hand, when the cooling load is small (in other words, when the pressure on the suction chamber side is low), the opening of the valve body for the flow control valve increases due to the extension of the bellows, and passes through the air supply passage from the discharge chamber. As a result, the flow rate of the refrigerant gas supplied to the crank chamber increases to increase the pressure in the crank chamber. As a result, the differential pressure between the pressure on the front surface side of the piston and the pressure on the rear surface side of the piston is increased, so that the stroke of the piston can be reduced and the discharge capacity of the refrigerant gas can be reduced.
JP 2006-17087 A (FIG. 2)

  By the way, instead of a flow rate control valve for controlling the flow rate of the refrigerant gas supplied from the discharge chamber to the crank chamber according to the pressure on the suction chamber side, for example, for estimating the drive torque of the variable capacity compressor, As shown in Japanese Laid-Open Patent Publication No. 2005-48714, the difference in controlling the flow rate of gas supplied from the discharge chamber to the crank chamber so that the differential pressure between the pressure on the discharge chamber side and the pressure on the suction chamber side becomes the set differential pressure. A pressure valve may be used.

  On the other hand, when a differential pressure valve is used for the variable capacity compressor, when the piston is switched to the destroke state (in other words, when the vehicle air conditioner is switched to the off state), the valve body for the differential pressure valve in the differential pressure valve Becomes fully open, and the pressure in the crank chamber rises rapidly. Therefore, when the frequency of switching the piston to the destroke state increases during the operation of variable displacement compression, the parts located around the crank chamber and the crank chamber (for example, the lug plate, the swash plate, which constitutes a part of the motion conversion mechanism, and There is a problem that the sealing parts and the like are easily deteriorated and the durability of the variable capacity compressor cannot be sufficiently increased.

  Accordingly, an object of the present invention is to provide a variable capacity compressor having a novel configuration that can solve the above-described problems.

  A first feature of the present invention (a feature of the invention described in claim 1) is a variable displacement compressor that compresses gas, and has a cylinder bore inside, and a crank chamber on the front side of the cylinder bore inside, A housing having a suction chamber and a discharge chamber communicating with the inside of the cylinder bore on the rear side of the cylinder bore in the interior, a drive shaft rotatably provided in the housing and extending in the front-rear direction, and reciprocating in the cylinder bore A movable single-headed piston, a motion conversion mechanism that is disposed in the crank chamber and converts a rotational motion of the drive shaft into a reciprocating motion of the piston, and communicates the crank chamber and the suction chamber. The bleed passage, the air supply passage that communicates the crank chamber and the discharge chamber, and is arranged in the middle of the air supply passage so that the set differential pressure can be varied according to the supplied current. For a differential pressure valve configured to open and close according to a change in the differential pressure between the renoid and the pressure on the discharge chamber side and the pressure on the suction chamber side, and when the supply of current to the solenoid is stopped A differential pressure valve for controlling a flow rate of gas supplied from the discharge chamber to the crank chamber so that a differential pressure between the pressure on the discharge chamber side and the pressure on the suction chamber side becomes a set differential pressure; A valve body for a pressure control valve disposed between the crank chamber and the differential pressure valve in the supply passage and configured to be fully closed when the pressure on the discharge chamber side exceeds a set pressure. And the pressure control valve.

  In the claims and the specification of the present application, “provided” means that it is indirectly provided via a separate member, and that it is formed.

  According to the first feature, by rotating the drive shaft, the motion conversion mechanism can convert the rotational motion of the drive shaft into the reciprocating motion of the piston, in other words, the piston is moved to the drive shaft. It can be reciprocated in conjunction with the rotation. Thereby, the gas sucked from the suction chamber can be compressed in the cylinder bore, and the compressed gas can be discharged from the cylinder bore to the discharge chamber.

  Further, during the operation of the variable capacity compressor, when the set differential pressure is lowered by the solenoid, the flow rate of the gas supplied from the discharge chamber to the crank chamber via the supply passage decreases, The pressure in the crank chamber is reduced. As a result, the differential pressure between the pressure on the front surface side of the piston and the pressure on the rear surface side of the piston is reduced, so that the stroke of the piston can be increased and the gas discharge capacity can be increased.

  On the other hand, when the set differential pressure is increased by the solenoid, the flow rate of the gas supplied from the discharge chamber to the crank chamber via the supply passage is increased, and the pressure in the crank chamber is increased. As a result, the differential pressure between the pressure on the front surface side of the piston and the pressure on the rear surface side of the piston is increased, so that the stroke of the piston can be reduced and the gas discharge capacity can be reduced.

  Further, when the supply of current to the solenoid is stopped, the valve body for the differential pressure valve is fully opened, the pressure in the crank chamber is brought close to the pressure on the discharge chamber side, and the piston is brought into a destroke state. Can be switched. Here, when the piston is switched to the destroke state, if the pressure on the discharge chamber side becomes equal to or higher than a set pressure, the valve body for the pressure control valve is fully closed, and the pressure in the crank chamber increases rapidly. Can be suppressed.

  According to a second feature of the present invention (a feature of the invention described in claim 2), in addition to the first feature, a communication passage communicating the crank chamber side and the discharge chamber side with the valve body for the pressure control valve. The gist is that is formed.

  According to a third feature (feature of the invention described in claim 3) of the present invention, in addition to the first or second feature, the motion conversion mechanism includes a lug plate integrally provided on the drive shaft. A swash plate that is provided on the rear side of the lug plate in the drive shaft so as to be tiltable, is connected to the lug plate, and a peripheral portion thereof is slidably engaged with the piston. Is the gist.

  As described above, according to the present invention, according to the invention described in any one of claims 1 to 3, even when the differential pressure valve is used in the variable capacity compressor, the piston When switching to the destroke state, a sudden pressure increase in the crank chamber can be suppressed, so even if the frequency of switching the piston to the destroke state during the variable displacement compression operation increases, the crank chamber and Parts located around the crank chamber are unlikely to deteriorate, and the durability of the variable capacity compressor can be sufficiently enhanced.

  An embodiment of the present invention will be described with reference to FIGS. 1 to 3.

  Here, FIG. 1 is a cross-sectional view of a variable capacity compressor according to an embodiment of the present invention, FIG. 2 (a) is a schematic diagram showing a normal state of a pressure control valve, and FIG. 2 (b) is a pressure diagram. FIG. 3A is a schematic diagram showing a fully closed state of the control valve, FIG. 3A is a schematic diagram showing a normal state of the pressure control valve of another embodiment, and FIG. 3B is a diagram of the pressure control valve of another embodiment. It is a schematic diagram which shows a fully closed state. In the figure, “F” indicates the forward direction, and “R” indicates the backward direction.

  As shown in FIG. 1, a variable capacity compressor 1 according to an embodiment of the present invention is used in a vehicle air conditioner and includes a housing 3. The housing 3 includes a cylinder block 5, a front housing 7 provided on the front side of the cylinder block 5, and a rear housing 11 provided on the rear side of the cylinder block 5 via a valve plate 9. .

  The cylinder block 5 is formed with a plurality of cylinder bores 13 along the circumferential direction. In other words, the housing 3 has a plurality of cylinder bores 13 inside. The front housing 7 has a crank chamber 15 inside. In other words, the housing 3 has a crank chamber 15 on the front side of the cylinder bore 13 inside. Further, the rear housing 11 has a suction chamber 17 and a discharge chamber 19 communicating with the plurality of cylinder bores 13 in other words. In other words, the housing 3 is disposed behind the cylinder bore 13 inside the suction chamber 17. And a discharge chamber 19. The suction chamber 17 is disposed so as to surround the discharge chamber 19, and the suction chamber 17 and the discharge chamber 19 are connected to an external refrigerant circuit (not shown).

  The valve plate 9 is formed with a plurality of suction holes (not shown) communicating with the plurality of cylinder bores 13 and the suction chamber 17, and in one direction from the suction chamber 17 to the cylinder bore 13 on the front side of each suction hole. A suction reed valve (not shown) that allows only flow is provided. Further, the valve plate 9 is formed with a plurality of discharge holes (not shown) communicating with the plurality of cylinder bores 13 and the discharge chamber 19, and the rear side of each discharge hole leads from the cylinder bore 13 to the discharge chamber 19. Discharge reed valves (not shown) that allow flow in only one direction are provided.

  A drive shaft 21 extending in the front-rear direction is rotatably provided in the housing 3 via a plurality of bearings 23. Although not shown, the front end of the drive shaft 21 is linked to an engine (an example of an external drive source) via a pulley, a timing belt, and the like. Further, a lip seal 25 is provided between the front housing 7 and the front end portion of the drive shaft 21 to prevent refrigerant gas from leaking. In addition to the lip seal 25, a seal member (not shown) such as a gasket is provided at an appropriate position of the housing 3.

  A single-headed piston 27 is provided in each cylinder bore 13 so as to be able to reciprocate, and each piston 27 has a pair of shoes 29 on its head. The crank chamber 15 is provided with a motion converting mechanism 31 that converts the rotational motion of the drive shaft 21 into the reciprocating motion of the plurality of pistons 27. The specific configuration of the motion converting mechanism 31 is as follows. It becomes like this.

  That is, a lug plate 33 is integrally provided on the drive shaft 21, and the lug plate 33 includes a lug plate protruding piece 35 protruding rearward. Further, a journal 37 is provided behind the lug plate 33 in the drive shaft 21 so as to be movable in the front-rear direction and tiltable via a sleeve (not shown). The journal 37 projects forward and is journaled. A projecting piece 39 is provided, and the journal projecting piece 39 is connected to the lug plate projecting piece 35 via a connecting link 41 and a plurality of connecting pins 43.

  The journal 37 is integrally provided with the swash plate 45. In other words, the drive shaft 21 is provided with the swash plate 45 so as to be movable forward and backward through the sleeve and the journal 37 and tiltable. Yes. The swash plate 45 is connected to the lug plate 33 via a journal 37, and the peripheral portion of the swash plate 45 is engaged with a pair of shoes 29 in the plurality of pistons 27 so as to be slidable.

  A front spring 47 capable of urging the journal 37 (in other words, the swash plate 45) in the rearward direction is provided on the front side of the journal 37 in the drive shaft 21, and the rear of the journal 37 in the drive shaft 21 is provided. On the side, a rear spring 49 capable of urging the swash plate 45 forward is provided.

  From the cylinder block 5 to the valve plate 9 (in the cylinder block 5 and the valve plate 9), a bleed passage 51 that continuously communicates the crank chamber 15 and the suction chamber 17 is formed continuously. An air supply passage 53 that communicates between the crank chamber 15 and the discharge chamber 19 is continuously formed from the cylinder block 5 to the rear housing 11 (in the cylinder block 5, the valve plate 9, and the rear housing 11). Yes.

  In the middle of the air supply passage 53, a differential pressure valve 55 is disposed. The differential pressure valve 55 is configured so that a differential pressure (Pd−Ps) between the pressure Pd on the discharge chamber side and the pressure Ps on the suction chamber side is a set differential pressure. Thus, the flow rate of the refrigerant gas supplied from the discharge chamber 19 to the crank chamber 15 is controlled. Further, as shown in Japanese Patent Application Laid-Open No. 2005-48714, the differential pressure valve 55 includes a solenoid 57 that can change a set differential pressure according to a supplied current, a pressure Pd on the discharge chamber side, and a pressure Ps on the suction chamber side. The differential pressure valve valve body 59 is configured to open and close in response to a change in the differential pressure (Pd−Ps) and to be fully opened when the supply of current to the solenoid 57 is stopped. In addition, since the specific structure of the differential pressure | voltage differential valve 55 is well-known, the description is abbreviate | omitted.

  As shown in FIGS. 1 and 2 (a) and 2 (b), a narrowed portion 61 having a reduced cross section is formed between the crank chamber 15 and the differential pressure valve 55 in the air supply passage 53. A pressure control valve 63 is disposed in the part 61. The pressure control valve 63 includes a pressure control valve valve element 65 that can be opened and closed, and a spring 67 that biases the pressure control valve valve element 65 in the opening direction. When the pressure Pd on the discharge chamber 19 side exceeds the set pressure, 65 is configured to move in the closing direction against the urging force of the spring 67 and to be fully closed.

  Further, as shown in FIGS. 3A and 3B, the pressure control valve valve body 65 may be formed with a communication passage 69 communicating the crank chamber 15 side and the discharge chamber 19 side. Thereby, even if the valve body 65 for pressure control valves is a fully-closed state, the communication state of the crank chamber 15 side and the discharge chamber 19 side can be maintained.

  Then, the effect | action and effect of embodiment of this invention are demonstrated.

  By rotating the drive shaft 21 by driving the engine, the lug plate 33, the journal 37, and the swash plate 45 are rotated, and the rotational motion of the drive shaft 21 is converted into the reciprocating motion of the plurality of pistons 27 by the motion conversion mechanism 31. In other words, the plurality of pistons 27 can be reciprocated in conjunction with the rotation of the drive shaft 21. Thereby, the refrigerant gas sucked from the suction chamber 17 can be compressed in the plurality of cylinder bores 13, and the compressed refrigerant gas can be discharged from the plurality of cylinder bores 13 to the discharge chamber 19.

  Further, if the set differential pressure is lowered by the solenoid 57 during the operation of the variable capacity compressor 1, the flow rate of the refrigerant gas supplied from the discharge chamber 19 to the crank chamber 15 via the supply passage 53 decreases. Then, the pressure in the crank chamber 15 is reduced. As a result, the differential pressure between the pressure on the front surface side of the piston 27 and the pressure on the rear surface side of the piston 27 is reduced, and the stroke of the piston 27 can be increased to increase the discharge capacity of the refrigerant gas.

  On the other hand, when the set differential pressure is increased by the solenoid 57, the flow rate of the refrigerant gas supplied from the discharge chamber 19 to the crank chamber 15 via the supply passage 53 is increased, and the pressure in the crank chamber 15 is increased. . As a result, the differential pressure between the pressure on the front surface side of the piston 27 and the pressure on the rear surface side of the piston 27 increases, and the stroke of the piston 27 can be reduced to reduce the discharge capacity of the refrigerant gas.

  Further, when the supply of current to the solenoid 57 is stopped, the differential pressure valve valve body 59 is fully opened, the pressure in the crank chamber 15 is brought close to the pressure on the discharge chamber 19 side, and the piston 27 is in the destroke state. You can switch to Here, when the piston 27 is switched to the destroke state, if the pressure Pd on the discharge chamber 19 side becomes equal to or higher than the set pressure, the pressure control valve valve body 65 is fully closed, and the crank chamber 15 suddenly changes. Increase in pressure can be suppressed.

  As described above, according to the embodiment of the present invention, even when the differential pressure valve 55 is used in the variable capacity compressor 1, the rapid pressure increase in the crank chamber 15 is suppressed when the piston 27 is switched to the destroke state. Therefore, even if the frequency of switching the piston 27 to the destroke state during the operation of the variable displacement compressor 1 increases, the crank chamber 15 and parts located around the crank chamber 15 (for example, the lug plate 33 and the swash plate 45). , Seal parts such as the lip seal 25) are not easily deteriorated, and the durability of the variable capacity compressor 1 can be sufficiently enhanced.

  In addition, this invention is not restricted to description of the above-mentioned embodiment, It can implement in a various aspect. Further, the scope of rights encompassed by the present invention is not limited to these embodiments.

It is sectional drawing of the variable capacity compressor which concerns on embodiment of this invention. FIG. 2A is a schematic diagram showing a normal state of the pressure control valve, and FIG. 2B is a schematic diagram showing a fully closed state of the pressure control valve. FIG. 3A is a schematic diagram illustrating a normal state of a pressure control valve according to another aspect, and FIG. 3B is a schematic diagram illustrating a fully closed state of the pressure control valve according to another aspect.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Variable capacity compressor 3 Housing 13 Cylinder bore 15 Crank chamber 17 Suction chamber 19 Discharge chamber 21 Drive shaft 27 Piston 29 Shoe 31 Motion conversion mechanism 33 Lug plate 45 Swash plate 51 Extraction passage 53 Supply passage 55 Differential pressure valve 57 Solenoid 59 Differential pressure valve Valve body 61 Restriction portion 63 Pressure control valve 65 Pressure control valve valve body 67 Spring 69 Communication passage

Claims (3)

In the variable capacity compressor (1) for compressing gas,
It has a cylinder bore (13) inside, has a crank chamber (15) on the front side of the cylinder bore (13) inside, and communicates with the cylinder bore (13) on the rear side of the cylinder bore (13) inside the cylinder bore (13). A housing (3) having a suction chamber (17) and a discharge chamber (19);
A drive shaft (21) rotatably provided in the housing (3) and extending in the front-rear direction;
A single-headed piston (27) provided in the cylinder bore (13) so as to be capable of reciprocating;
A motion conversion mechanism (31) disposed in the crank chamber (15) and converting a rotational motion of the drive shaft (21) into a reciprocating motion of the piston (27);
An extraction passage (51) communicating the crank chamber (15) and the suction chamber (17);
An air supply passage (53) communicating the crank chamber (15) and the discharge chamber (19);
A solenoid (57) disposed in the middle of the air supply passage (53) and capable of changing a set differential pressure in accordance with a supplied current, a pressure (Pd) on the discharge chamber (19) side, and the suction chamber (17) A differential pressure valve configured to open and close according to a variation in the differential pressure (Pd−Ps) of the pressure (Ps) on the side and to be fully opened when supply of current to the solenoid (57) is stopped. And a differential pressure (Pd−Ps) between the pressure (Pd) on the discharge chamber (19) side and the pressure (Ps) on the suction chamber (17) side becomes a set differential pressure. A differential pressure valve (55) for controlling the flow rate of gas supplied from the discharge chamber (19) to the crank chamber (15),
It is disposed between the crank chamber (15) and the differential pressure valve (55) in the air supply passage (53), and is fully closed when the pressure (Pd) on the discharge chamber (19) side exceeds a set pressure. A variable capacity compressor comprising: a pressure control valve (63) including a pressure control valve valve body (65) configured to become:   2. The communication passage (69) that connects the crank chamber (15) side and the discharge chamber (19) side is formed in the pressure control valve valve body (65). Variable capacity compressor. The motion conversion mechanism (31)
A lug plate (33) provided integrally with the drive shaft (21);
The drive shaft (21) is provided on the rear side of the lug plate (33) so as to be tiltable, and is connected to the lug plate (33) so that the peripheral portion is slidably contacted with the piston (27). The variable capacity compressor according to claim 1 or 2, further comprising a combined swash plate (45).

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