WO1999028627A1 - Variable capacity swash plate type clutchless compressor - Google Patents

Abstract

A variable capacity swash plate type clutchless compressor wherein a discharge control valve (30) is provided in an intermediate portion of a discharge passage (39) adapted to introduce a refrigerant gas in a discharge chamber (12) to a discharge port (1a), the discharge passage (39) being cut off by the discharge control valve (30) when a difference between the pressure in a suction chamber (13) and that in the discharge chamber (12) becomes not higher than a predetermined level, an outflow of the refrigerant gas from the discharge port (1a) to a condenser (84) being consequently prevented, whereby the refrigerant gas is internally circulated, the unnecessity of providing a mechanism for internally circulating the refrigerant gas on a shaft (5) enabling the suction chamber (13) to be provided on the outer side of the discharge chamber (12) in a rear head (3), the shaft being axially stabilized since a sufficiently large preload can be imparted thereto.

Description

 Description Variable-capacity swash plate type clutchless compressor Technical field

 The present invention relates to a variable-capacity swash plate-type clutchless compressor, and more particularly, to a variable-capacity swash-plate-type clutchless compressor to which engine driving force is constantly transmitted. About the lesser. Background art

 As a conventional clutchless compressor, there is a variable-capacity swash plate type clutchless compressor. In this clutchless compressor, the inclination angle of the swash plate changes in response to the suction pressure, the stroke of the piston changes, and the discharge rate increases or decreases.

 If a variable displacement swash plate type clutchless compressor with a minimum discharge capacity of zero is used as a clutchless compressor, the heat load will decrease. At that time (at the time of the clutch phase of the compressor with a clutch), the refrigerant cools the evaporator, and frost forms on the surface of the evaporator. However, the evaporator freezes and ventilation becomes difficult, and the cooling function may be impaired.

As a technology to prevent this, when the heat load is reduced, the refrigerant is circulated inside the compressor, and the discharge amount to the outside of the compressor is reduced to zero. (Japanese Unexamined Patent Publication No. 7-253080). In this clutchless compressor, the inclination angle of the swash plate decreases with a decrease in the heat load, and the swash plate pushes the transmission cylinder toward the rear side, and the transmission cylinder resets the shut-off body. To the keyer side. When the inclination of the swash plate becomes minimum, the intake passage is closed by the shut-off body, and the inflow of low-pressure refrigerant gas from the evaporator is prevented. On the other hand, the discharge chamber and the crank chamber are communicated by the control valve, and the high-pressure refrigerant gas in the discharge chamber flows to the crank chamber, and the refrigerant gas is almost moved to the capacitor side. Not flowing. In this way, when the inclination angle of the swash plate is at a minimum (at the time of the minimum strain stroke), most of the refrigerant gas circulates inside the compressor and the refrigeration capacity is reduced to zero. can do. Also, since the refrigerant gas circulates internally, the sliding parts are sufficiently lubricated and cooled.

 However, since a structure is adopted in which a transmission cylinder and a blocker for closing the suction passage are mounted on the rotating shaft, the discharge chamber must be arranged outside the suction chamber in the cylinder head. In addition, the management of seals with outside air becomes stricter. For example, higher machining accuracy and an appropriate tightening amount of bolts (ports for connecting the cylinder block and the head) are required.

In addition, since a structure is employed in which a preload is applied to the rotating shaft by a spring via a transmission cylinder, a bearing, and a blocking body, a sufficient preload cannot be applied to the rotating shaft due to its structure. As a result, the rotating shaft and the rotating support are not stabilized in the axial direction, and the noise due to vibration increases. Especially when the load is large under heavy load, the spring that urges the breaker is extended and noise is generated. It will be larger.

 Furthermore, since the shut-off body rotates with the rotation of the rotating shaft, the spring for biasing the shut-off body may rotate together with the shut-off body to break the screw, making it impossible to open and close the suction passage. I did.

 The present invention has been made in view of such circumstances, and its object is to facilitate management of seals against outside air, suppress noise, and further improve reliability. It is an object of the present invention to provide a variable-capacity swash plate-type clutchless compressor that can be used. Disclosure of the invention

In order to solve the above-mentioned problems, a variable-capacity swash plate type clutchless compressor according to the present invention is slidably and tiltably mounted on a rotating shaft and rotates integrally with the rotating shaft. A swash plate, a crank chamber for accommodating the swash plate, a suction chamber for accommodating a refrigerant gas to be sent to the compression chamber, a first passage for communicating the crank chamber with the suction chamber, A discharge chamber containing the refrigerant gas discharged from the compression chamber, a discharge port for sending the refrigerant gas from the discharge chamber to the capacitor side, and a refrigerant in the discharge chamber described above in the discharge port. A discharge passage for introducing gas, a second passage for communicating the discharge chamber with the above-mentioned crank chamber, and a passage provided in the middle of the second passage so as to be disposed when the heat load becomes large. A variable-capacity swash plate clutch equipped with a pressure control valve for shutting off the second passage. In less co Npure Tsu support, provided in the middle of the discharge passage, the pressure difference between the discharge chamber and the suction chamber that closes the discharge passage can and equal to or less than a predetermined value ejection An outlet control valve is provided.

 When the pressure difference between the suction chamber and the discharge chamber becomes equal to or less than a predetermined value, the discharge passage is blocked by the discharge control valve, so that the refrigerant gas is prevented from flowing out from the discharge port to the condenser, and the refrigerant gas is discharged. Circulates internally.

 By employing this discharge control valve, there is no need to mount a mechanism for opening and closing the suction passage on the rotating shaft, and the suction chamber can be located outside the discharge chamber in the housing. Since it is possible, it is easy to manage the seal with the outside air. In addition, the spring for applying the preload to the rotating shaft does not break as the rotating shaft rotates and does not break the screw, making it impossible to open and close the suction passage, improving the reliability of the compressor. I do.

 Furthermore, since sufficient preload can be applied to the rotating shaft, the rotating shaft is stabilized in the axial direction, and noise due to vibration can be suppressed.

 In the variable displacement type swash plate type clutchless compressor according to the present invention, the discharge control valve is a spool valve, and one of the spool valves is configured to urge one of the spool valves with the pressure of the suction chamber. The urging force of the member acts and the pressure of the discharge chamber acts on the other side of the spool valve.

 The spool valve linearly reciprocates according to the pressure in the suction chamber and the difference between the urging force of the urging member and the pressure in the discharge chamber, and opens and closes the discharge passage.

The adoption of a spool valve as the suction control valve makes it possible to simplify the structure. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a longitudinal sectional view showing a variable-capacity swash plate type clutchless compressor according to one embodiment of the present invention.

 FIG. 2 is an arrow view along the line II-II of FIG.

 FIG. 3 is an enlarged vertical sectional view showing a state where the discharge passage is opened.

 FIG. 4 is an enlarged vertical sectional view showing a state in which the discharge passage is closed. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

 FIG. 1 is a longitudinal sectional view showing a variable-capacity swash plate type clutchless compressor according to one embodiment of the present invention, and FIG. 2 is an arrow along the line II-II in FIG. FIG.

 One end of the cylinder block 1 of this variable displacement swash plate type clutchless compressor has a lid head 3 via a valve plate 2 and a floating head on the other end. Each head 4 is fixed. The cylinder block 1 is provided with a plurality of cylinder bores 6 at predetermined intervals in a circumferential direction around a shaft (rotating shaft) 5. A piston 7 is slidably accommodated in each of the cylinder pores 6. Cylinder block 1 is provided with discharge port 1a which leads to the inlet of capacitor 84.

A crank chamber 8 is formed in the front head 4, and a swash plate 10 is accommodated in the crank chamber 8. Slant On the sliding surface 10 a of the plate 10, a retainer 50 supporting the spherical end portion 11 a of the connecting grid 11 1 so as to be able to relatively roll is provided with a retainer 5 3. It is held at. A bearing 55 is attached to the boss 10 b of the swash plate 10, and a retainer 53 is attached to the boss 1 O b of the swash plate 10 via the bearing 55. 3 is rotatable relative to the swash plate 10. The bearing 55 is prevented from coming off by a tongue 54 fixed to the boss 10b. The other end 11 b of the connecting groove 11 is fixed to the piston 7.

 The shoe 50 includes a shoe body 51 that supports the distal end surface of the connecting groove 11a so as to be relatively rotatable, and an end of the connecting groove 11a. 1 a a す る 1 1 1 1 1 1 1 1 1.

 A discharge chamber 12 and a suction chamber 13 are formed in the lid 3. The suction chamber 13 is arranged so as to surround the discharge chamber 12 (see Fig. 2). The lid 3 is provided with an inlet 3a which leads to an outlet of an evaporator (not shown). A discharge passage 39 that communicates between the discharge port 1 a and the discharge chamber 12 is provided in the lid 3 and the valve plate 2.

 FIG. 3 is an enlarged vertical sectional view showing a state in which the discharge passage 39 is open, and FIG. 4 is an enlarged vertical sectional view showing a state in which the discharge passage 39 is closed.

In the middle of the discharge passage 39, a discharge control valve 30 is provided. This discharge control valve 30 is a bottomed cylindrical spool valve 3 1, a spring (biasing member) 32, and a stopper \ ° 56 are provided. The stopper \ ° 5 6 is fixed to the lid head 3 by a cap 59, the spring 32 is housed in the spool valve 31, and one end of the spring 32 is connected to the stopper. The other end of the spring 32 is in contact with the bottom of the spool valve 31. The internal space 33 of the spool valve 31 is formed through a center hole 56 a of the stower 56 and a passage 83 provided in the cap 59 and the lid 3. Then, it communicates with the suction chamber 13.

 The urging force of the spring 32 and the pressure of the suction chamber 13 act on one of the spool valves 31 in the valve closing direction (the direction in which the valve opening decreases). On the other side of the spool valve 31, the pressure of the discharge chamber 12 acts in the valve opening direction (the direction in which the valve opening increases).

 FIG. 3 is an enlarged vertical sectional view showing a state in which the discharge passage is opened.

 The discharge chamber 12 and the crank chamber 8 communicate with each other via a passage (second passage) 57. A control valve (pressure control valve) 81 is provided in the middle of the passage. The outlet valve 81 operates only when the heat load is large, and shuts off the passage 57.

 The suction chamber 13 and the crank chamber 8 communicate with each other via a passage (first passage) 58. The passage 58 is composed of an orifice 58 a formed in the valve plate 2 and a passage 58 b formed in the cylinder block 1.

The valve plate 2 includes a discharge port 16 for communicating the compression chamber 82 with the discharge chamber 12, and a suction port 15 for communicating the compression chamber 82 with the suction chamber 13. Way around Are provided at predetermined intervals. The discharge port 16 is opened and closed by a discharge valve 17, and the discharge valve 17 is attached to the rear end side of the valve plate 2 on the rear head side, together with a valve retainer 18 and a port 19, nut. Fixed by G20. The suction port 15 is opened and closed by a suction valve 21, and the suction valve 21 is disposed between the valve plate 2 and the cylinder block 1.

 The radial bearing 24 and the thrust bearing 25 support the rear side of the shaft 5, and the front side of the shaft 5 is rotatably supported by the radial bearing 26. Has been done. A female screw 1b is provided at the center of the cylinder block 1, and an adjust nut 84 is screwed to the female screw 1b. By tightening the adjust nut 84, the preload is applied to the shaft 5 via the thrust bearing 25. A pulley 90 is fixed to a front end of the shaft 5 with a bolt 92, and a belt 91 is hung on the pulley 90.

 A thrust flange 40 for transmitting the rotation of the shaft 5 to the swash plate 10 is fixed to the shaft 5, and the thrust flange 40 is fixed to the thrust flange 40. It is supported on the inner wall surface of the front head 4 via a last bearing 33. The thrust flange 40 and the swash plate 10 are connected via a hinge mechanism 41, and the swash plate 10 can be inclined with respect to an imaginary plane perpendicular to the shaft 5. .

The swash plate 10 is slidably and tiltably mounted on the shaft 5. The hinge mechanism 41 includes a bracket 10e provided on the front surface 10c of the swash plate 10 and a linear guide provided on the bracket 10e. It is composed of a groove 10 f and a rod 43 screwed to the swash plate side end surface 40 a of the thrust flange 40. The longitudinal axis of the guide groove 10 f is inclined at a predetermined angle with respect to the front face 10 c of the swash plate 10. The spherical portion 43a of the rod 43 is fitted into the guide groove 10f so as to be relatively slidable.

 Next, the operation of the variable capacity type swash plate type clutchless compressor will be described.

 The rotational power of the vehicle engine (not shown) is constantly transmitted to the pulley 90 and the shaft 5 via the belt 91, and the rotational force of the shaft 5 is changed to the thrust flange 40. The swash plate 10 is transmitted to the swash plate 10 via the hinge mechanism 41, and the swash plate 10 rotates.

 Since the rotation of the swash plate 10 causes the shaft 50 to relatively rotate on the rear surface 10 a of the swash plate 10, the rotation force from the swash plate 10 causes the linear reciprocating motion of the piston 7. Is converted to The piston 7 reciprocates in the cylinder bore 6, and as a result, the volume of the compression chamber 82 in the cylinder bore 6 changes, and the suction, compression, and discharge of the refrigerant gas are caused by this volume change. The operation is sequentially performed, and a refrigerant gas having a capacity corresponding to the inclination angle of the swash plate 10 is discharged. At the time of suction, the suction valve 21 opens, and low-pressure refrigerant is sucked from the suction chamber 13 into the compression chamber 82 in the cylinder bore 6, and at the time of discharge, the discharge valve 17 opens and the compression chamber 82 High-pressure refrigerant gas is discharged from the discharge chamber 12 to the discharge chamber 12.

When the heat load is reduced (compressed compressor The passage 57 is opened by the operation of the control valve 81, and high-pressure refrigerant gas flows out of the discharge chamber 12 to the crank chamber 8 and the crank valve is turned off. The pressure in chamber 8 increases. The force applied to the front face of piston 7 during the compression stroke increases, and the sum of the forces applied to the front face of piston 7 becomes the piston 7 As a result of exceeding the sum of the forces applied to the surfaces, the inclination angle of the swash plate 10 becomes small.

 When the pressure difference between the suction chamber 13 and the discharge chamber 12 falls below a predetermined value P 1 (for example, 1.5 MPa), the suction chamber 13 acting on the spool valve 31 of the discharge control valve 30 When the combined force of the pressure of the spring 32 and the biasing force of the spring 32 overcomes the pressure of the discharge chamber 12 acting on the spool valve 31, the spool valve 31 moves in the valve closing direction and the discharge passage 3 9 closes (see Fig. 4). As a result, the outflow of the refrigerant gas from the discharge port 1a to the capacitor 84 is prevented.

 When the inclination angle of the swash plate 10 is at the minimum, the refrigerant gas flows again through the suction chamber 13, the compression chamber 82, the discharge chamber 12, the passage 57, the crank chamber 8, and the passage 58 again. Return to suction chamber 13.

 On the other hand, when the heat load increases, the passage 57 is closed by the action of the outlet valve 81, and the high-pressure refrigerant flows from the discharge chamber 12 to the crank chamber 8. The outflow of gas is prevented, and the pressure in the crank chamber 8 decreases. Then, the force applied to the front surface of the piston 7 during the compression stroke is reduced, and the total force applied to the front surface of the piston 7 is reduced to the piston 7 As a result, the inclination angle of the swash plate 10 increases.

Also, the pressure in the suction chamber 13 becomes low, and the suction chamber 13 When the pressure difference between the discharge chamber 12 and the discharge chamber 12 exceeds a predetermined value P2, the pressure of the discharge chamber 12 acting on the spool valve 3 1 and the pressure of the suction chamber 13 acting on the spool valve 3 1 and the spring When the combined force with the biasing force of 32 is overcome, the spool valve 31 moves in the valve opening direction and the discharge passage 39 opens (see FIG. 3). As a result, the refrigerant gas in the discharge chamber 12 is sent from the discharge port 1a to the inlet of the capacitor 84.

 According to the variable-capacity swash plate type clutchless compressor of this embodiment, a mechanism for opening and closing the suction passage (such as a conventional transmission cylinder or a blocker) is attached to the shaft 5. Since there is no necessity, the suction chamber 13 can be arranged outside the discharge chamber 12 in the lid head 3, and the management of the seal with the outside air becomes easy. Furthermore, the spring for preloading the shaft 5 does not cut off as the shaft 5 rotates and does not prevent the suction passage from being opened and closed. Reliability is improved.

 Also, a sufficient preload can be applied to the shaft 5 by tightening the adjust nut 83, so that the shaft 5 and the thrust flange 40 can be moved in the axial direction. And the noise due to vibration can be suppressed.

 Furthermore, since the structure of the cylinder block 1 and the like is not complicated, parts can be shared with the variable-capacity swash plate type compressor with a clutch.

 In addition, the use of the spool valve 31 as the discharge control valve allows the structure to be simplified.

In the above-described embodiment, the discharge control valve 31 is used as a switch. Although the description has been given of the case where the pool valve 31 is used, a valve other than the spool valve such as a rotary valve may be used. Industrial applicability

 As described above, the variable-capacity swash plate type clutchless compressor according to the present invention is useful as a refrigerant compressor for an air conditioner for an automobile.

Claims

The scope of the claims 1. A swash plate that is slidably and tiltably mounted on the rotating shaft and rotates integrally with the rotating shaft, a crank chamber that houses the swash plate, and a suction that houses refrigerant gas to be sent to the compression chamber. Chamber, a first passage communicating the crank chamber and the suction chamber, a discharge chamber containing the refrigerant gas discharged from the compression chamber, and a refrigerant gas from the discharge chamber. A discharge port for sending out to the capacitor side, a discharge passage for guiding the refrigerant gas in the discharge chamber to the discharge port, and a discharge port for communicating the discharge chamber with the crank chamber. A variable displacement swash plate type of clutch having a second passage and a pressure control valve provided in the middle of the second passage and shutting off the second passage when a thermal load is increased. At the touchless compressor,  A discharge control valve that is provided in the middle of the discharge passage and closes the discharge passage when a pressure difference between the suction chamber and the discharge chamber becomes a predetermined value or less. Variable capacity swash plate type clutchless compressor.  2. The discharge control valve is a spool valve, and the pressure of the suction chamber and the urging force of the urging member act on one of the spool valves, and the discharge chamber acts on the other of the spool valve. 2. The variable-capacity swash plate type clutchless compressor according to claim 1, wherein said pressure acts.