JPH0599138A - Swash plate type variable capacity compressor - Google Patents

Abstract

PURPOSE:To provide a swash plate type variable capacity compressor which is of a type where a swash plate is inclined around a central point and which is accurately controllable of delivery capacity. CONSTITUTION:In a swash plate type variable capacity compressor wherein a swash plate 42 is arranged in such a way that an inclination angle with a main shaft 20 is variable centering around a central point, transmission mechanisms 43, 44, 61, and 61a transmit more slightly an axial movement of a moving member 60 to the swash plate 42 in a range, where the inclination angle of the swash plate 42 is large, in comparison with a range other than the aforesaid range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swash plate type variable displacement compressor used in, for example, a vehicle air conditioner.

[0002]

2. Description of the Related Art Among conventional swash plate type variable displacement compressors,
A housing, a main shaft rotatably arranged in the housing, a swash plate having a variable inclination angle on the main shaft, a moving member provided on the main shaft so as to be movable in the axial direction of the main shaft, A transmission mechanism for changing the inclination angle of the swash plate by transmitting the movement of the moving member in the axial direction to the swash plate, the swash plate being inclined with respect to the main axis about a center point of the swash plate. There is a swash plate type variable displacement compressor that is provided with variable angles (see, for example, Japanese Patent Application Laid-Open No. 58-162782). A cylinder is provided in the housing, and a piston is slidably inserted in the cylinder. The oscillating plate or the conversion member such as a shu converts the rotational motion of the swash plate accompanying the rotation of the main shaft into a linear reciprocating motion, and this linear reciprocating motion is transmitted to the piston so that the piston reciprocates in the cylinder. Made of
As a result, the fluid is sucked and discharged.
On the other hand, the movement of the moving member in the axial direction is transmitted to the swash plate by the transmission mechanism, so that the inclination angle of the swash plate changes. The displacement of the inclination angle of the plate is approximately 1: 1 and is proportional.

As described above, in the conventional swash plate type variable displacement compressor of this type, the inclination angle of the swash plate (the angle formed by the plane orthogonal to the axis of the main shaft and the plane parallel to the radial direction of the swash plate). )
Is variable about the center of the swash plate. With such a configuration, the piston stroke changes and the position of the top dead center of the piston moves due to the change in the tilt angle of the swash plate. Therefore, when the piston is at the top dead center, the volume of the space formed between the upper end surface of the piston and the upper end surface of the cylinder, that is, the dead volume, changes according to the inclination angle of the swash plate. When this dead volume increases, the compression efficiency decreases. In this type of conventional variable displacement swash plate compressor, the piston stroke was changed by changing the inclination angle of the swash plate, and the discharge capacity was increased or decreased by this, but the dead volume caused by the inclination angle of the swash plate was changed. The compression efficiency was changed by the increase / decrease, and the discharge capacity was also increased / decreased.

[0004]

As described above, the compression efficiency changes as the dead volume increases or decreases, but there is no proportional relationship between the increase / decrease amount of the dead volume and the change amount of the compression efficiency. Even if it increases a little, compression efficiency will fall remarkably, and if the dead volume then increases, the decrease in compression efficiency will be a slight change. Therefore, in the conventional swash plate type variable displacement compressor of this type, when controlling the displacement,
Since the change of the compression efficiency caused by the increase / decrease of the dead volume is involved, there is a disadvantage that it is difficult to arbitrarily control the discharge capacity.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a swash plate type variable displacement compressor capable of accurately and arbitrarily controlling the discharge capacity of the compressor.

[0006]

According to the present invention, a housing, a main shaft rotatably arranged in the housing, a swash plate provided on the main shaft with a variable inclination angle, and the main shaft on the main shaft. A moving member provided so as to be movable in the axial direction of
And a transmission mechanism for changing the inclination angle of the swash plate by transmitting the movement of the moving member in the axial direction to the swash plate, the swash plate with respect to the main axis about a center point of the swash plate. In a swash plate type variable displacement compressor having a variable tilt angle, in the range where the tilt angle of the swash plate is large, the transmission mechanism has the shaft of the moving member as compared with a range other than the range. A swash plate type variable displacement compressor is obtained, in which directional movement is slightly transmitted to the swash plate.

[0007]

When the dead volume is small in the swash plate type variable displacement compressor, which is involved in the change of the compression efficiency caused by the increase / decrease of the dead volume when controlling the discharge capacity,
That is, it is important to perform the increase / decrease of the dead volume in the range where the inclination angle of the swash plate is large in order to accurately and arbitrarily control the discharge volume. In the case of the swash plate type variable displacement compressor of the present invention, the transmission mechanism slightly transmits the movement of the moving member in the axial direction to the swash plate in a range where the inclination angle of the swash plate is large as compared with a range other than this range. Because of this, the increase / decrease of the dead volume is subtly carried out in this range.

[0008]

1 is a sectional view of a swash plate type variable displacement compressor according to an embodiment of the present invention. The front housing member 1 and the rear housing member 2 are butted against each other with the seal member 3 interposed. The front housing member 1 integrally has a front cylinder block 4. The front cylinder block 4 is formed with a plurality of front side cylinders 5 parallel to a main shaft 20 described later. The cylinders 5 are formed at equal intervals so as to surround the main shaft 20. Similarly, the rear housing member 2 integrally has a rear cylinder block 6. The rear cylinder block 6 has a plurality of rear cylinders 7 parallel to the main shaft 20. These cylinders 7 are formed at equal intervals so as to face the cylinder 5 on the front side and surround the main shaft 20. Further, the rear cylinder block 6 has a protruding portion 8, and a central hole 9 is formed in the center portion of the rear cylinder block 6.

A front cylinder head 11 is attached to one surface of the front housing member 1 with a front valve plate device 10 interposed. The front cylinder head 11 has a suction chamber 12, a discharge chamber 13 and a boss portion 14. An electromagnetic clutch (not shown) is attached to the boss portion 14. On one surface of the rear housing member 2,
A rear cylinder head 16 is attached with a rear valve plate device 15 interposed. Rear cylinder head 16
Has a suction chamber 17 and a discharge chamber 18. The front housing member 1, the rear housing member 2, the front cylinder head 11, and the rear cylinder head 16 described above.
The housing 19 is composed of.

The main shaft 20 integrally includes a front small diameter portion 21, a large diameter portion 22 and a rear small diameter portion 23. The small front diameter portion 21 is rotatably supported by a radial needle bearing 24 provided in the front cylinder block 4. The rear small-diameter portion 23 is the rear cylinder block 6
It is rotatably supported by a radial needle bearing 25 provided therein. Thereby, the spindle 20 is
It is rotatably supported in the housing 19.

The front cylinder block 4 is provided with a thrust needle bearing 30, and the end face of the large diameter portion 22 on the front small diameter portion 21 side is abutted against the thrust needle bearing 30. Thereby, the main shaft 20 is thrust-supported. On the other hand, a female screw 32 is formed on the projecting portion 8 of the rear cylinder block 6, and an adjusting screw 33 is screwed onto the female screw 32. The adjusting screw 33 is rotated to rotate the main shaft 2
It moves in the axial direction of 0, that is, in the axial direction. Further, since the adjusting screw 33 is abutted against one end of the main shaft 20, the axial position of the main shaft 20 can be adjusted by rotating the adjusting screw 33.

A center pin 40 is attached to the spindle 20. The center line of the center pin 40 is the main shaft 20.
Orthogonal to the axis of. A center ring 41 surrounding the main shaft 20 is rotatably attached to the center pin 40. A substantially disc-shaped swash plate 42 is attached to the centering 41. When the centering 41 and the swash plate 42 are rotatably attached to the center pin 40, the center line of the center pin 40 passes through the center points of the centering 41 and the swash plate 42. Therefore, the swash plate 42 is rotated around the center point of the main shaft 20.
It can be freely tilted against. The swash plate 42 has a spindle 2
A substantially triangular arm 43 parallel to 0 is provided.
A pin 44 parallel to the center pin 40 is provided at the tip of the arm 43.

The double-headed piston 50 has one end slidably inserted into the front cylinder 5 and the other end slidably inserted into the rear cylinder 7. A recess 51 having a curved surface corresponding to a spherical surface is formed at the center of the double-headed piston 50. In this recess 51,
Two shoes 52, 53 having a spherical surface are provided. A peripheral portion of the swash plate 42 is slidably inserted between the shoes 52 and 53. Therefore, the swash plate 4
When 2 rotates with the main shaft 20, the double-headed piston 50
It reciprocates in the axial direction according to the inclination angle of the swash plate 42 to perform suction / discharge operation. Thus, in the case of this embodiment, the shoes 52, 53
Is a conversion member that converts the rotational movement of the swash plate 42 into a linear reciprocating movement.

A sleeve 60 is mounted on the main shaft 20 as a moving member so as to be movable in the axial direction. A long hole 61 is formed on the side surface of the sleeve 60. The pin 44 is slidably inserted into the long hole 61. The wall surface that defines the long hole 61 is a cam surface 6 that is in sliding contact with the pin 44.
It consists of 1a. The long hole 61 has an arc shape, and therefore the cam surface 61a also has an arc shape. This cam surface 6
1a has a pin 44 when the sleeve 60 moves in the axial direction.
The pin 44 is formed so as to be in sliding contact with the center pin 40 and to be rotated around the center pin 40. That is, the arm 4 described above
3, long hole 61 formed in pin 44 and sleeve 60
In addition, the cam surface 61a constitutes a transmission mechanism that transmits the axial movement of the sleeve 60 to the swash plate 42 to change the inclination angle of the swash plate 42. The long hole 61 of this transmission mechanism
Is configured to limit the rotation range of the pin 44 so that the swash plate 42 has a small inclination angle within a very limited range from the maximum inclination angle (the state shown in FIG. 1). Further, as described above, the elongated hole 61 and the cam surface 61a are formed in an arc shape, but this is a range in which delicate control is required to increase / decrease the dead volume, that is, the inclination angle of the swash plate 42 is large. Within the range, compared to the range where the inclination angle of the swash plate 42 is small,
This is for slightly transmitting the axial movement of the sleeve 60 to the swash plate 42. As a result, when the sleeve 60 is moved in the axial direction within a range where the inclination angle of the swash plate 42 is large,
The inclination angle of the swash plate 42 changes subtly according to the movement.

As described above, the swash plate 42 is variable within a very limited range from the maximum tilt angle. In this case, the discharge capacity control of the compressor depends on the increase or decrease of the piston stroke according to the tilt angle of the swash plate 42. In addition to the control of the discharge capacity, it is largely influenced by the change in the compression efficiency caused by the increase or decrease of the dead volume due to the change of the inclination angle of the swash plate 42. That is, since the compression efficiency changes remarkably even if the dead volume is slightly increased or decreased, the discharge volume can be controlled from the maximum to almost 0 by slightly changing the dead volume. Therefore, in the present embodiment, the swash plate 4 is close to the maximum angle because the change in the discharge capacity is large particularly near the maximum angle.
Since the inclination angle of 2 can be delicately controlled, the discharge volume can be accurately and arbitrarily controlled from the maximum to the minimum. A large hole 63 is formed in the main shaft 20, and the large hole 63 prevents the pin 44 from interfering with the main shaft 20 when the pin 44 rotates around the center pin 40.

A recess 70 is formed in the center of the rear cylinder head 16, and an approximately tray-shaped actuator 71 is axially slidably arranged in the recess 70. With the actuator 71 as a boundary, the valve plate device 15 side of the recess 70 is the suction chamber 17, and the opposite side is the pressurizing chamber 72. A coil spring 73 is provided in the pressurizing chamber 72. This coil spring 73
Urges the actuator 71 in a direction of separating the actuator 71 from the valve plate device 15. The pressurizing chamber 72 communicates with the discharge chamber 18 through a communication passage 74. A filter 75 and an orifice 76 are provided in the communication passage 74. Therefore, the discharge chamber pressure is reduced and constantly introduced into the pressurizing chamber 72. The fluid introduced into the pressurizing chamber 72 from the discharge chamber 18 can escape to the suction chamber 17 via the control valve 77. By controlling the communication between the pressurizing chamber 72 and the suction chamber 17 by the control valve 77, the pressurizing chamber 7
The pressure in 2 is controlled, and as a result, the position of the actuator 71 is controlled.

A plurality of actuating pins 80 are provided at the center of the rear cylinder block 6 so as to be slidable in the axial direction. These actuating pins 80
One end of each is fixed to the actuator 71.
A thrust needle bearing 81 is interposed between the actuating pin 80 and the sleeve 60. The thrust needle bearing 81 is arranged in the central hole 9 of the rear cylinder block 6 so as to be axially movable in the central hole 9. Thrust needle bearing 8
The first fixed ring 82 is fixed to the other end of the actuating pin 80. The rotating wheel 83 of the thrust needle bearing 81 is fixed to the sleeve 60. Therefore, the axial movement of the actuator 71 is transmitted to the sleeve 60 via the actuator pin 80 and the thrust needle bearing 81. As a result, the tilt angle of the swash plate 42 can be controlled by controlling the pressurizing chamber pressure by the control valve 76.

Although the present embodiment is a swash plate type variable displacement compressor of the type having cylinders on both sides of the housing,
The present invention is not limited to this, and the present invention can be applied to a normal swash plate type variable displacement compressor having a cylinder on one side of the housing.

[0019]

The swash plate type variable displacement compressor according to the present invention comprises:
The transmission mechanism is designed to slightly transmit the axial movement of the moving member to the swash plate within the range in which a slight increase / decrease in dead volume is required. As a result, the discharge capacity of the compressor can be accurately and arbitrarily controlled.

[Brief description of drawings]

FIG. 1 is a sectional view of a swash plate type variable displacement compressor according to an embodiment of the present invention.

[Explanation of symbols]

 19 Housing 20 Spindle 42 Swash Plate 43 Arm 44 Pin 60 Sleeve 61 Long Hole 61a Cam Surface

Claims (1)

[Claims] 1. A housing, a main shaft rotatably arranged in the housing, a swash plate having a variable inclination angle on the main shaft, and a main shaft movably in an axial direction of the main shaft. A moving member and a transmission mechanism that changes the inclination angle of the swash plate by transmitting the movement of the moving member in the axial direction to the swash plate, the swash plate having a center point of the swash plate as a center. In the swash plate type variable displacement compressor in which the tilt angle with respect to the main shaft is variably provided, the transmission mechanism moves within the range where the tilt angle of the swash plate is large as compared with the range other than the range. A swash plate type variable displacement compressor characterized in that the axial movement of a member is slightly transmitted to the swash plate.