JPH0518355A - Variable capacity type compressor - Google Patents

Abstract

PURPOSE:To attempt the omit of an electromagnetic clutch and the realization of wide range capacity control of a compressor starting from zero capacity. CONSTITUTION:A sleeve 8 which is fitted around a drive shaft 4 so as to pivot a rotary swash plate 7 slant-movably and a stop means 40 which can hold the sleeve 8 to the minimum capacity position are provided. A hydraulic actuation chamber 21a which is formed in the sleeve 8 and can individually move the sleeve 8 straight and a hydraulic pump 20 which is connected to the drive shaft 4 and can circulate the enclosed oil in a crank room 15 are provided. Further, a pressurized oil is supplied from the hydraulic pump 20 to the hydraulic operation room 21a selectively through an oil passage 25 a changeover valve 44 which can displace the stop means 40 as well as the sleeve 8 forcely from the minimum capacity position to the zero capacity position is provided. Thereby, since an electromagnetic clutch can be omitted by the realization of zero capacity running, the saving of fuel comsumption by the decrease of an engine load in addition to the decrease of a compressor weight can be contributed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement compressor suitable mainly for vehicle air conditioning.

[0002]

2. Description of the Related Art A conventional compressor of this type is disclosed in Japanese Patent Laid-Open No.
The one disclosed in Japanese Patent Publication No. 16177 is known. As shown in FIG. 3, the compressor has a crank chamber 52 formed in a housing 51, a rotor 54 connected to a drive shaft 53 in the crank chamber 52, and a hinge mechanism 55 for the rotor 54.
A rotary swash plate 56 supported through the rotary swash plate 56, and a swing plate 57 attached along the rotary swash plate 56 in a state in which rotation is restricted,
A plurality of pistons 59 that reciprocate in the bore 58 by the swing of the swing plate 57, a suction chamber 60 that supplies fluid into the bore 58, a discharge chamber 61 that discharges the compressed fluid, and a crank chamber 52. Is provided in a bleed passage 63 that connects the suction chamber 60 with the suction chamber 60, and mainly includes a valve means 62 that senses the pressure in the suction chamber 60 and adjusts the opening degree of the bleed passage 63. The hinge mechanism 55 for connecting the rotor 54 and the rotary swash plate 56 is provided with a long hole on the rotor 54 side, and the pin portion mounted on the rotary swash plate 56 side is inserted into the long hole. The rotary swash plate 56 is supported by the rotor 54 so that the rotary swash plate 56 can be tilted within the range of the length of the long hole.

According to this structure, the following effects can be obtained. That is, when the opening degree of the extraction passage 63 is adjusted by the operation of the valve means 62 according to the suction chamber pressure and the crank chamber pressure is changed at any time by the blow-by gas leaking from inside the bore 58, it is applied to the rear surface of the piston 59. Along with the force, the equilibrium point of the moment acting on the rotary swash plate 56 also changes, and the tilt angles of the rotary swash plate 56 and the oscillating plate 57 change, and this changes the amount of the fluid taken into the bore 58 with the fluctuation of the piston stroke. Capacity is controlled. That is, the suction chamber pressure is controlled to be a preset value by such a variable volume mechanism.

[0004]

Now, according to the variable volume mechanism as described above, the valve means 6 is operated as the suction pressure is lowered.
2 operates so as to reduce the opening degree of the extraction passage 63, and controls so as to increase the crank chamber pressure to reduce the capacity of the compressor, but the valve means 62 causes the extraction passage to decrease due to a further decrease in heat load. Even when the compressor 63 is completely closed and the capacity of the compressor is further reduced due to the further increased crank chamber pressure, the lower limit is set to the preset minimum capacity (about 1
0% capacity). This is because effective compression work is not performed in an extremely small capacity range of zero or close to it, and capacity recovery control based on the differential pressure between the suction chamber pressure and the crank chamber pressure becomes virtually impossible. .. Also,
With the recent compressors that require lubrication of each sliding part in the machine with mixed oil particles in the refrigerant, seizure and deterioration of service life caused by insufficient refrigerant (lubrication) are factors that force the lower limit regulation of capacity control to be performed. Can be pointed out as.

Therefore, since the minimum capacity of the compressor is regulated in this way, the electromagnetic clutch is disconnected depending on the environment in which the vehicle air conditioner is used, such as in a cold region, for the purpose of protecting the compressor and preventing frost on the evaporator. It is necessary to stop the compressor via. In other words, the electromagnetic clutch connected to the compressor is widely put into practical use as an indispensable constituent element of the current vehicle air-conditioning system, but the electromagnetic clutch is not only affected by the shock at the start, but also the driving feeling. It is also a problem that cannot be overlooked that the efficiency of the alternator that supplies power is surprisingly low, and the load on the engine is increasing accordingly. In other words, if it is possible to omit the electromagnetic clutch, it will be easy to understand that it will not only contribute to the pursuit of fuel efficiency, but will also bring about an epoch-making result in weight reduction of the compressor.

SUMMARY OF THE INVENTION The present invention has as technical problems to be solved the omission of an electromagnetic clutch and the realization of wide-range capacity control of a compressor starting from zero capacity.

[0007]

In order to solve the above problems, the present invention provides a crank chamber, a drive shaft extending in the crank chamber and rotatably supported, and a rotor fixed to the drive shaft. A rotary swash plate pivotally supported by a sleeve fitted to the drive shaft so as to be tiltable and supported by the rotor through a hinge mechanism, and a rotary swash plate which rotates along an inclined surface of the rotary swash plate. And a swing plate which is mounted in a state where it is restrained and is allowed only to swing in response to the rotation of the drive shaft, and a reciprocating motion in each bore due to the swing of the swing plate. A plurality of pistons, a suction chamber for supplying fluid into the bore, a discharge chamber for discharging the fluid compressed in the bore, and valve means for adjusting the pressure in the crank chamber. Means to adjust the differential pressure between the suction chamber pressure and the crank chamber pressure to change the tilt angle of the rotary swash plate. In the variable displacement compressor configured to change the intake volume of the fluid into the bore by the above, a stop means for holding the sleeve at the minimum capacity position and the sleeve formed in the sleeve are provided. And a hydraulic pump that directly moves the valve, a hydraulic pump that is connected to the drive shaft and circulates the enclosed oil in the crank chamber, and a hydraulic pump that selectively moves from the hydraulic pump to the hydraulic chamber through an oil passage. A novel structure is adopted in which pressure oil is supplied and a switching valve for forcibly displacing the sleeve from the minimum capacity position to the zero capacity position together with the stopping means.

[0008]

When the compressor is stopped together with the engine, the rotating swash plate and the oscillating plate remain stationary with a constant inclination angle due to the pressure balance inside the machine, while the switching valve is also held in the normal position. There is. When the drive shaft is rotated following the start of the engine, the oil discharged from the hydraulic pump, which is linked to the drive shaft, is immediately supplied to the hydraulic working chamber via the switching valve, urging the sleeve to move and rotating. Since the swash plate and the oscillating plate are displaced to the upright (zero capacity) posture, the compressor starts operating in a state of almost no load, and at the same time, the lubrication oil passage that is always in conduction to the lubrication necessary part in the compressor is used. Then, the discharged oil is continuously fed.

When a signal such as a switch operation for instructing the activation of the air conditioner is issued due to the rise of the vehicle compartment temperature from such a state, the position of the switching valve is synchronously switched by the excitation of the solenoid, and the hydraulic working chamber has a hydraulic pump. Is communicated with the suction side of, and the sleeve is retracted by the urging force of the stopping means that had been succumbing to the hydraulic pressure supplied to the hydraulic operating chamber,
A tilt angle corresponding to the minimum capacity is given to the rotating swash plate and the oscillating plate.
Of course, there is no change in the point that the subsequent capacity control is performed by the capacity variable mechanism unique to the compressor according to the heat load, but during that time, the advance limit of the sleeve is restricted to the minimum capacity position by the function of the above-mentioned restraining means. To be done.

When the environment changes thereafter, excessive cooling still occurs even with the minimum capacity operation, or when the air conditioner is stopped to prevent the evaporator from frosting, the switching valve is deenergized by the solenoid and the spring is urged. Returning to the normal position, the movement of the sleeve through the supply of pressure oil to the hydraulic working chamber causes the compressor to shift to the zero capacity state again while continuing the operation.

[0011]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing a part of the compressor according to the present embodiment, in which a front housing 2 and a rear housing 3 are connected to the front and rear of a cylinder block 1 which is the main body of the compressor. The cylinder block 1 and the front housing 2 rotatably support a drive shaft 4 which is linked to an engine (not shown), for example. A rotor 5 is mounted on the drive shaft 4 in the front housing 2.
Is fixed, and a guide slot 5b is penetratingly provided at the tip of the support arm 5a extending from the rotor 5. A pin 6 is slidably fitted in the guide elongated hole 5b, and a protruding edge portion of a rotary swash plate 7 is connected to the pin 6. A sleeve 8 is slidably fitted onto a drive shaft 4 which is separated from the rotor 5, and support shafts 8a protruding from both left and right sides of the sleeve 8 are provided with a rotary swash plate 7 (not shown). The rotary swash plate 7 is pivotally supported so as to be tiltable around a support shaft 8a by being fitted in the engaging hole of the.

An oscillating plate 9 is fitted and supported on the boss portion of the rotary swash plate 7 so as to be relatively rotatable, and a spherical projection 9 is provided on the outer edge portion.
Rotation is restrained by engaging a with a notch groove 2a provided in the front housing 2, and at the same time, the piston 11 in the bore 10 formed in the cylinder block 1 and the oscillating plate 9 are connected to the piston rod 12 Are connected by. Therefore, the rotational movement of the drive shaft 4 is converted into the back-and-forth reciprocating swing of the swing plate 9 via the rotor 5 and the rotary swash plate 7,
The refrigerant gas sucked from the suction chamber 13 into the bore 10 by the piston 11 directly moving in the bore 10 is compressed and discharged into the discharge chamber 14. The stroke of the piston 11 and the tilt angle of the oscillating plate 9 can be changed at any time according to the pressure difference between the pressure in the crank chamber 15 and the pressure in the suction chamber 13.

Reference numeral 16 is built in, for example, the rear housing 3, and in response to the suction chamber pressure, the discharge chamber 14 and the crank chamber 15 are provided.
The valve means 16 is a valve means for adjusting the opening degree of the air supply passage 17 connecting with the valve means 16. The valve means 16 includes a bellows 16a enclosing a spring or a gas body of a predetermined pressure, and a valve body 16b connected to the bellows 16a. The bellows 16a is expanded and contracted against the pressure in the suction chamber to control the opening and closing of the valve seat 17a of the air supply passage 17 through the valve body 16b.
Reference numeral 18 denotes an extraction passage that constantly connects the crank chamber 15 and the suction chamber 13.

Although the basic configuration of the variable displacement compressor described above is not particularly different from the known configuration, the most characteristic configuration of the compressor of the present invention is the variable displacement mechanism described in detail below and the hydraulic control mechanism. Is included. That is, a trochoidal type hydraulic pump (hereinafter referred to as a pump) 20 connected to the end of the drive shaft 4 is housed in the rear housing 3, and the suction side of the pump 20 is connected to an oil passage 21 through a crank chamber. The enclosed oil in 15 is introduced. On the other hand, the sleeve 8 is formed with a hollow portion that encloses the flange portion 4a bulging from the drive shaft 4, and the illustrated right chamber sandwiching the flange portion 4a is a sealed hydraulic working chamber 21a. Is a breathable ventilation chamber 21b.
Further, a discharge oil passage 22 communicating with the discharge side of the pump 20.
A switching valve 24 controlled by a solenoid operation synchronized with an operation command of the air conditioner is provided between the return oil passage 23 that communicates with the suction side, and the hydraulic operating chamber 21a includes the drive shaft 4 and a cylinder block. It is possible to selectively communicate with the discharge oil passage 22 or the return oil passage 23 of the pump 20 via the oil passage 25 extending through the first and the rear housing 3 and the switching valve 24.

The sleeve 8 is provided at the rear of the sleeve 8.
A stopping means 30 for restricting the limit position of the sleeve 8 in two ways is provided. The stopping means 30 is fixed to the drive ring 4 and a locking ring 31 protruding at the rear end of the sleeve 8. The locking ring 31
Plate 3 that interferes with the sleeve and regulates the sleeve 8 to the zero capacity position
2 and a coil spring 33 which is interposed between the sleeve 8 and the stop plate 32 and regulates the advance limit of the sleeve 8 in the normal displacement control region to the minimum displacement position by its tension. ing. Reference numeral 26 is a lubricating oil passage that branches from the discharge oil passage 22 and extends in the same manner as the oil passage 25, and the end thereof opens into the shaft sealing chamber 27 of the front housing 2.

This embodiment is constructed as described above,
When the compressor is stopped together with the engine, the rotating swash plate 7 and the oscillating plate 9 remain stationary with a constant inclination angle due to the pressure balance inside the machine, while the switching valve 24 is also held in the normal position by the spring bias. Has been done. Then, when the drive shaft 4 is rotated following the start of the engine, the discharge oil of the pump 20 interlocking with the drive shaft 4 is immediately supplied to the hydraulic pressure working chamber 21a via the switching valve 24 and the oil passage 25. That is, the hydraulic pressure acting on the sleeve 8 is advanced against the biasing force of the coil spring 33 to a position where its locking ring 31 abuts against the stop plate 32, so that the rotary swash plate 7 and the swing plate 9 stand upright. Since the compressor is displaced to the (zero capacity) posture, the compressor starts to operate in a state of almost no load, and at the same time, a fixed amount of the above-mentioned discharge is made through a lubricating oil passage 26 which is always connected to a lubrication necessary portion such as a shaft seal device. Oil is delivered.

When a signal such as a switch operation for instructing the activation of the air conditioner is issued due to the rise of the vehicle compartment temperature from such a state, the position of the switching valve 24 is synchronously switched by the excitation of the solenoid, and the hydraulic working chamber 21a. Is connected to the suction side of the pump 20, and the sleeve 8 retreats due to the repulsive force of the coil spring 33, which had so far succumbed to the hydraulic pressure supplied to the hydraulic working chamber 21a, to cause a rotational inclination. An inclination angle corresponding to the minimum capacity is given to the plate 7 and the swing plate 9. In other words, the compressor smoothly starts up from zero capacity and reaches the minimum capacity (about 10
% Capacity) state. In this way, the effective compression work required for displacement control is started, and thereafter, the crank chamber pressure is adjusted by the valve means 16 that responds to the suction chamber pressure, and the normal displacement control mode is entered. In addition,
During that time, the moving limit of the sleeve 8 is determined by the coil spring 33.
It is regulated to the minimum capacity position by the resistance of.

Then, when the environment changes thereafter, excessive cooling still occurs even with the minimum capacity operation, or when the air conditioner is stopped to prevent the frost of the evaporator, the switching valve 24 is demagnetized by the solenoid and biased by the spring.
Returns to the normal position and the compressor 8 is moved to the zero capacity state again while continuing the operation by the movement of the sleeve 8 through the supply of the pressure oil to the hydraulic working chamber 21a.

FIG. 2 shows another embodiment of the present invention.
In the present embodiment, the stopping means 40 is provided in the cylinder block 1 and the cylinder chamber 41,
And a stopper 42a which is fitted into the crank chamber 15 and extends into the crank chamber 15. The plunger 42 has a stroke defined by a bottom wall of the cylinder chamber 41 and a closing ring 43 fixed to the opening end. Has been identified. And cylinder chamber 4
1 is selectively communicable with the discharge oil passage 22 or the return oil passage 23 of the pump 20 via an oil passage 45 extending from the cylinder block 1 via the rear housing 3 and a switching valve 44.

Therefore, when pressure oil is supplied from the discharge oil passage 22 to the cylinder chamber 41 and the plunger 42 reaches the front end of the stroke, the tip of the rod 42a interferes with the expanded end surface 8b of the sleeve 8 and The advancing limit of the sleeve 8 is restricted to the minimum capacity position, and the hydraulic working chamber 21a is communicated with the return oil passage 23 during that time. On the other hand, when the switching valve 44 is switched and pressure oil is supplied from the discharge oil passage 22 to the hydraulic working chamber 21a, the sleeve 8 exceeds the advance limit up to that point and reaches zero determined by the trailing end of the stroke of the plunger 42. The cylinder chamber 41 is displaced to the capacity position, and the cylinder chamber 41 is communicated with the return oil passage 23 during that time.

As described above, the present embodiment is characterized in that the stopping means 40 for restricting the advancing limit of the sleeve 8 in two ways are surely operated by the hydraulic pressure. Is exactly the same as the previous embodiment.
The lubricating oil passage 26 in this example is directly connected to the discharge side of the pump 20 through the opening at the end of the drive shaft 4. Further, in both of the above-described embodiments, the stopping means 3 is used.
Although the zero capacity position is regulated by 0 and 40, it is needless to say that this can also be regulated by the guide elongated hole 56 that guides the pin 6.

[0022]

As described above in detail, the variable displacement compressor according to the present invention is structured such that a hydraulic control mechanism is incorporated in the variable displacement mechanism so as to forcibly control from the minimum capacity to the zero capacity. Therefore, by realizing the zero capacity operation, the electromagnetic clutch can be omitted. Therefore, not only the weight of the compressor can be reduced, but also the fuel consumption can be remarkably contributed by reducing the engine load.

Further, even if the electromagnetic clutch remains, the shock is surely alleviated by the zero-capacity activation, so that the driving feeling can be maintained excellently.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view showing a variable displacement compressor according to another embodiment of the present invention.

FIG. 3 is a sectional view showing a conventional variable displacement compressor.

[Explanation of symbols]

4 is a drive shaft, 5 is a rotor, 7 is a rotating swash plate, and 8 is a sleeve.
Reference numeral 9 is a swing plate, 10 is a bore, 11 is a piston, 13 is a suction chamber, 14 is a discharge chamber, 15 is a crank chamber, 16 is a valve means, 20 is a hydraulic pump, 21a is a hydraulic working chamber, and 24 is a switch. Valves, 30, 40 are stop means

Claims (1)

Claim: What is claimed is: 1. A crank chamber, a drive shaft which extends into the crank chamber and is rotatably supported, a rotor fixed to the drive shaft, and a drive shaft fitted to the drive shaft. Attached to the rotary swash plate, which is pivotally supported by a tilted sleeve and supported by the rotor through a hinge mechanism, and the rotation of which is restricted along the inclined surface of the rotary swash plate. An oscillating plate that is only allowed to oscillate according to the rotation of the drive shaft; a plurality of pistons connected to the oscillating plate and reciprocating in respective bores by oscillating the oscillating plate; A suction chamber for supplying a fluid into the bore, a discharge chamber for discharging the fluid compressed in the bore, and a valve means for adjusting the pressure in the crank chamber are included. By adjusting the differential pressure with the chamber pressure and changing the tilt angle of the rotating swash plate, the fluid bore In a variable displacement compressor configured to change the intake volume into a compressor, a stop means for holding the sleeve at a minimum capacity position and a linear movement of the sleeve formed on the sleeve are independently performed. A hydraulic operating chamber for operating the hydraulic pump, a hydraulic pump connected to the drive shaft for circulating the enclosed oil in the crank chamber, and a hydraulic pump for selectively supplying hydraulic oil from the hydraulic pump to the hydraulic operating chamber via an oil passage. A variable displacement compressor provided with a stop valve and a switching valve for forcibly displacing the sleeve from a minimum displacement position to a zero displacement position.