JP3092396B2 - Capacity return structure of clutchless one-sided piston type variable displacement compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls a tilt angle of a swash plate by a difference between a pressure in a crank chamber and a suction pressure through a single-headed piston, and controls the tilt angle of a swash plate through a pressure supply passage connecting a discharge pressure area and the crank chamber. A clutch that supplies pressure in the discharge pressure region to the crank chamber and that releases pressure in the crank chamber to the suction pressure region through a pressure release passage connecting the crank chamber and the suction pressure region to regulate pressure in the crank chamber. The present invention relates to a capacity return structure in a single-sided piston type variable displacement compressor.

[0002]

2. Description of the Related Art In a variable displacement swinging swash plate compressor disclosed in Japanese Patent Application Laid-Open No. 3-143725, an electromagnetic clutch is provided for connecting and disconnecting power transmission between an external drive source and a rotary shaft of the compressor. Not used. Eliminating the electromagnetic clutch can eliminate the drawback of poor physical feeling due to the ON-OFF shock particularly in a vehicle-mounted configuration, and can reduce the weight and cost of the entire compressor.

In the variable displacement type swinging swash plate type compressor disclosed in the above-mentioned conventional publication, the pressure in the crank chamber accommodating the swash plate is rapidly increased to bring the swash plate inclination angle to 0 °, and the discharge capacity to zero. It is designed to drop. When returning the capacity by increasing the inclination angle of the swash plate from zero, the hydraulic actuator is pushing the swash plate in the inclination increasing direction. The hydraulic actuator operates by opening an electromagnetic on-off valve.

[0004]

However, if the discharge capacity continues to be zero, the pressure in the crank chamber drops to the suction pressure range, and the refrigerant gas pressure in the compressor becomes uniform. Then, the swash plate may start to tilt without permission, and the capacity may be restored without permission.

SUMMARY OF THE INVENTION An object of the present invention is to provide a displacement-reducing structure in a clutchless one-sided piston type variable displacement compressor which can accurately perform a displacement without causing a voluntary displacement return.

[0006]

According to the present invention, there is provided:
A bypass passage connecting the discharge pressure region and the suction pressure region,
A bypass closing valve openable said bypass passage when the swash plate inclination is minimum inclination, the minimum inclination angle defining the spring and clutch-less one-sided piston type variable displacement compressor provided with biasing the front Kihasu plate to tilt decreasing direction configure the capacity recovery structure, the minimum inclination angle defining the spring when the swash plate inclination is minimum inclination was Unishi'm not act on the swash plate.

[0007]

When the frost is likely to occur in the evaporator, the swash plate tilt angle becomes the minimum tilt angle, and the bypass passage opens. By opening the bypass passage, the refrigerant gas in the discharge pressure region flows to the suction pressure region, and the discharge refrigerant gas does not flow out to the external refrigerant circuit. Therefore, the occurrence of frost in the evaporator on the external refrigerant circuit is avoided. When the pressure reduction means closes the pressure supply passage connecting the discharge area and the crank chamber or enlarges the passage cross-sectional area of the discharge passage connecting the crank chamber and the suction pressure area, the pressure in the crank chamber decreases, The swash plate inclination shifts from the minimum inclination to the increasing direction. Due to the increase in the tilt angle, the discharge capacity increases, that is, the capacity is restored, and the bypass passage is closed. Since the inclination angle of the inclined plate spring action of the minimum inclination angle defining the spring when the minimum inclination angle does not act on the swash plate, the swash plate tilt angle immediately shifts from the minimum inclination angle to the increasing direction when lowering the pressure in the crank chamber.

[0008]

FIG. 1 shows a first embodiment of the present invention.
This will be described with reference to FIG. As shown in FIG. 1, a front housing 2 is joined to a front end of a cylinder block 1 which is a part of a housing of the entire compressor. A rear housing 3 is joined and fixed to the rear end of the cylinder block 1 via a valve plate 4, valve forming plates 5A and 5B, and a retainer forming plate 6. A deep groove ball bearing member 7 is mounted in the front housing 2.
A rotating support 8 is supported on the deep groove ball bearing member 7, and a rotating shaft 9 is fixed to the rotating support 8. The deep groove ball bearing member 7 receives both the load in the thrust direction and the load in the radial direction acting on the rotating shaft 9 via the rotating support 8.

The front end of the rotating shaft 9 projects outside from the crank chamber 2a via the front housing 2, and a pulley 10 is screwed to this projected end. The pulley 10 is operatively connected to a vehicle engine via a belt 11. A lip seal 12 is interposed between the front end of the rotating shaft 9 and the front housing 2. Lip seal 1
2 prevents pressure leakage in the crank chamber 2a. Rotating shaft 9
The rear end is rotatably supported by the cylinder block 1 via a radial bearing 13.

A swash plate support 14 having a spherical shape is slidably supported on the rotating shaft 9, and a swash plate 15 is supported on the swash plate support 14 so as to be tiltable in the axial direction of the rotating shaft 9. . Connecting pieces 16 and 17 are fixed to the swash plate 15.
As shown in FIG. 2, a pair of guide pins 18 and 19 are fixed to the connecting pieces 16 and 17. A support arm 8a protrudes from the rotary support 8. A support pin 20 is rotatably supported by the support arm 8a and penetrates in a direction perpendicular to the rotation shaft 9. A pair of guide pins 18 and 19
Are slidably fitted into both ends of the support pin 20. The swash plate 15 is connected to the support pin 20 on the support arm 8a and the pair of guide pins 18 and 19, so that the swash plate 15
Can be tilted in the axial direction of the rotating shaft 9 around the center and can be rotated integrally with the rotating shaft 9. The tilt of the swash plate 15 is determined by the slide guide relationship between the support pin 20 and the guide pins 18 and 19,
The guide is guided by the sliding action of the swash plate support 14 and the support action of the swash plate support 14.

The maximum inclination angle of the swash plate 15 is regulated by the contact between the inclination regulating protrusion 8 b of the rotary support 8 and the swash plate 15.
A minimum inclination regulating ring 21 is fixed on the rotating shaft 9, and the minimum inclination of the swash plate 15 is regulated by the contact between the minimum inclination regulating ring 21 and the swash plate support 14. The minimum tilt angle of the swash plate 15 when the swash plate support 14 is in contact with the minimum tilt angle defining ring 21 is slightly larger than 0 °.

Step 9a on rotating shaft 9 and swash plate support 14
And a minimum inclination defining spring 55 is interposed therebetween. The contracted minimum inclination regulating spring 55 urges the swash plate support 14 in a direction in which the swash plate 15 has the minimum inclination. As shown in FIG. 5, the natural length of the minimum inclination defining spring 55 is different from that of the swash plate support 14 at the position where the swash plate 15 has the minimum inclination with the stepped portion 9a.
Is slightly shorter than the distance between. Therefore, when the swash plate support 14 is at the position where the swash plate tilt angle is the minimum, the spring force of the minimum tilt angle defining spring 55 becomes zero.

A single-headed piston 22 is accommodated in a cylinder bore 1a penetrating through the cylinder block 1 so as to be connected to the crank chamber 2a. A pair of shoes 23 is fitted into the neck 22a of the single-headed piston 22. Swash plate 1
The peripheral edge of 5 enters between the shoes 23, and the end faces of both shoes 23 are in contact with both surfaces of the swash plate 15. Therefore, the swash plate 15
Is converted into a reciprocating swing of the single-headed piston 22 through the shoe 23, and the single-headed piston 22 moves back and forth in the cylinder bore 1a.

As shown in FIGS. 1 and 3, a suction chamber 3a and a discharge chamber 3b are defined in the rear housing 3. A suction port 4a and a discharge port 4b are formed on the valve plate 4. A suction valve 5a is formed on the valve forming plate 5A, and a discharge valve 5b is formed on the valve forming plate 5B. Refrigerant gas in the suction chamber 3a is supplied to the suction port 4a
, The suction valve 5a is pushed away and flows into the cylinder bore 1a. The refrigerant gas that has flowed into the cylinder bore 1a is discharged to the discharge chamber 3b by pushing the discharge valve 5b out of the discharge port 4b by the forward movement of the single-headed piston 22. Discharge valve 5b
Abuts on the retainer 6 a on the retainer forming plate 6 to regulate the opening.

The swash plate support 14 has a minimum inclination defining ring 21.
When the swash plate 15 is in the minimum inclination state when the swash plate 15 is in contact with the swash plate 15, the stroke of the single-headed piston 22 is slight. The stroke amount is made as small as possible to the extent that a compression ratio is generated in the cylinder bore 1a to increase the swash plate inclination from the minimum inclination position, that is, the capacity return.

The stroke of the single-headed piston 22 changes according to the pressure difference between the pressure in the crank chamber 2a and the suction pressure in the cylinder bore 1a through the single-headed piston 22. That is, the inclination angle of the swash plate 15 which affects the compression capacity changes. The pressure in the crank chamber 2a is controlled by a control valve 24 attached to the rear housing 3. Crank chamber 2a and suction chamber 3a
Are communicated with each other via a pressure release passage 1b having a throttle action.

The internal structure of the control valve 24 will be described with reference to FIGS. A guide cylinder 27 is fixed to a hollow portion of the bobbin 26 that supports the solenoid 25.
A fixed iron core 28 is accommodated and fixed in 7. A movable iron core 29 is accommodated in the guide cylinder 27 so as to be able to approach and separate from the fixed iron core 28. A valve opening forced spring 30 is interposed between the fixed iron core 28 and the movable iron core 29. The movable iron core 29 is urged in a direction away from the fixed iron core 28 by the spring action of the valve opening forcing spring 30.

A valve housing 31A is fixedly connected to the bobbin 26 via a connecting member 32, and a spherical valve body 33 is accommodated in the valve housing 31A.
The valve housing 31 is provided with a discharge pressure introduction port 31a, a suction pressure introduction port 31b, a bypass port 31c, and a control port 31d. Discharge pressure introduction port 31
a communicates with the discharge chamber 3b via the discharge pressure introducing passage 34. The suction pressure introduction port 31b communicates with the suction chamber 3a via the suction pressure introduction passage 35, and is connected to the bypass port 31.
“c” communicates with the suction chamber 3 a via the bypass passage 36. The control port 31d communicates with the crank chamber 2a via the control passage 37. The discharge pressure introduction passage 34 and the control passage 37 constitute a pressure supply passage.

Spring receiver 38 in valve housing 31A
A return spring 39 and a valve support seat 40 are interposed between the valve body 33 and the valve body 33, and the valve body 33 receives the spring action of the return spring 39 in a direction to close the valve hole 31e.

A bellows fitting 44 is accommodated in the suction pressure detecting chamber 43 communicating with the suction pressure introduction port 31b in a state of being fixed to the movable iron core 29. The bellows fitting 44 and the spring receiver 45 are connected by a bellows 46, and a spring 47 is interposed between the bellows fitting 44 and the spring receiver 45. A transmission rod 48 is fixed to the spring receiver 45, and the tip of the transmission rod 48 contacts the valve body 33.

The valve housing 31A and its internal members constitute a capacity control valve 24a, and the valve body 33 opens and closes a valve hole 31e in response to a change in suction pressure in the suction pressure detection chamber 43. The valve housing 31 is provided in the valve housing 31A.
B is connected and fixed, and a spool-shaped valve element 41 is accommodated in the valve housing 31B. The valve body 41 is urged by the action of the spring 42 in a direction to close the valve hole 31f. When the valve hole 31f is closed, the communication between the discharge pressure introduction port 31a and the bypass port 31c is cut off.

A throttle hole 41 a is formed in the valve body 41, and the discharge pressure introduction port 31 a is always in communication with the accommodation chamber of the valve body 33. When the valve hole 31e is closed, the communication between the discharge pressure introducing port 31a and the control port 31d is cut off.

The valve housing 31B, the valve body 41a and the spring 42 therein constitute a bypass opening / closing valve 24b. That is, the control valve 24 includes a solenoid 25, a capacity control valve 24a, and a bypass opening / closing valve 24b.

An inlet (not shown) for introducing refrigerant gas into the suction chamber 3a and an outlet 1c for discharging refrigerant gas from the discharge chamber 3b are connected by an external refrigerant circuit 49. On the external refrigerant circuit 49, a condenser 50, an expansion valve 51, and an evaporator 5
2 is interposed. The expansion valve 51 controls the flow rate of the refrigerant according to the change in the gas pressure on the outlet side of the evaporator 52.

The solenoid 25 is controlled by the control computer C to excite and demagnetize it. The control computer C turns on the air conditioner operation switch 54 or turns on the accelerator switch 56
The solenoid 25 is excited by the FF, and the air conditioner operation switch 54 is turned off or the accelerator switch 56 is turned off.
N demagnetizes the solenoid 25. In the state shown in FIG. 1, the solenoid 25 is in an excited state. In the excited state of the solenoid 25, the movable iron core 29 is attracted to the fixed iron core 28 against the spring action of the valve opening forcing spring 30, as shown in FIGS.

When the solenoid 25 is excited, the bellows 46 is displaced in accordance with the fluctuation of the suction pressure Ps introduced from the suction pressure introduction port 31b, and this displacement is
8 to the valve body 33. The suction pressure Ps is spring 4
7, a set suction pressure Ps ₀ or less determined by the spring force of
Also, in a range that is not far from the set suction pressure Ps ₀ (provisionally represented as Ps ₀ ≧ Ps), when the suction pressure Ps is high (cooling load is large), the valve opening of the valve body 33 becomes small. When the pressure in the crank chamber 2a is higher than the suction pressure Ps, the refrigerant gas in the crank chamber 2a passes through the throttle passage 1b.
Through the suction chamber 3a. Therefore, the valve element 3
When the valve opening degree of the valve chamber 3 becomes small, the discharge chamber 3b is moved from the crank chamber 2
a, the pressure of the refrigerant in the crank chamber 2a decreases, and the inclination angle of the swash plate increases. That is, the discharge capacity increases. Conversely, when the suction pressure Ps is low (the cooling load is small), the valve opening of the valve body 33 increases. Therefore, the pressure in the crank chamber 2a increases, and the swash plate inclination angle decreases. That is, the discharge capacity is reduced.

When the refrigerant load Ps ₀ <Ps is very large, the valve opening of the valve body 33 becomes zero, and the refrigerant gas does not flow from the discharge chamber 3b to the crank chamber 2a. Therefore, the inclination angle of the swash plate becomes maximum.

Accordingly, the inclination angle of the swash plate 15 is regulated between the maximum inclination position where it contacts the inclination restriction protrusion 8b and the minimum inclination position where the swash plate support 14 contacts the minimum inclination restriction ring 21. That is, the discharge capacity is controlled within this inclination range of the swash plate 15.

When the solenoid 25 is demagnetized by turning off the air conditioner operation switch 54, the movable iron core 29 is separated from the fixed iron core 28 by the spring action of the valve opening forcible spring 30, as shown in FIG. Open. In this maximum opening state, the refrigerant gas discharged in the discharge chamber 3b rapidly flows into the crank chamber 2a via the discharge pressure introduction passage 34, the discharge pressure introduction port 31a, the valve hole 31e, the control port 31d, and the control passage 37, and The pressure inside the chamber 2a rapidly rises. Therefore, the swash plate 15 immediately shifts to the minimum inclination angle. Since the minimum tilt angle is not zero, the ejection, that is, the compression is performed slightly even in the minimum tilt state. Due to this compression, the inclination of the swash plate 15 can be returned.

The force acting on the valve body 41 in the closing direction is F +
The _{(Pd'-Ps) · S 1} . Here, F is the spring force of the spring 42, Pd 'is the pressure in the region between the valve bodies 33 and 41, S ₁
Is the cross-sectional area of passage of the bypass port 31c. Valve element 41
Force acting in the opening direction on the (Pd-Pd ') (S 2 -S
₁ ). However, S ₂ is the cross-sectional area of the chamber housing the valve body 41. The valve body 41 has a valve hole 31f due to the relationship between these two forces.
Open and close. That is, when the following equation (A) holds, the communication between the discharge pressure introducing passage 34 and the bypass passage 36 is interrupted, and when the following equation (B) holds, the discharge pressure introducing passage 34 is used.
And the bypass passage 36 communicate with each other. F + (Pd′−Ps) · S ₁ > (Pd−Pd ′) (S ₂ −S ₁ ) ·· (A) F + (Pd′−Ps) · S ₁ <(Pd−Pd ′) (S ₂ − S ₁ )... (B) Equations (A) and (B) can be rewritten into the following equations (C) and (D). F + (Pd−Ps) S ₁ > (Pd−Pd ′) S ₂ ... (C) F + (Pd−Ps) S ₁ <(Pd−Pd ′) S _2. After passing through the hole 41a, a pressure difference occurs before and after the hole 41a due to the throttle action of the throttle hole 41a. This pressure difference is the difference between the discharge pressure Pd and the pressure Pd ′.
d> Pd ′. If there is no refrigerant gas flow in the throttle hole 41a, there is no pressure difference between front and rear, and Pd = Pd '. For example, if the discharge pressure Pd is equal to the suction pressure Ps, the pressure Pc of the crank chamber 2a is also equal to the suction pressure Ps, and no refrigerant gas flow occurs in the throttle hole 41a.

When the valve body 33 is at the maximum opening, the force relationship represented by the formula (C) and the force relationship represented by the formula (D) correspond to the discharge pressure P
Switching is possible according to a change in the magnitude relationship between d and the suction pressure Pd. That is, when the valve body 33 is at the maximum opening degree,
The flow rate of the refrigerant gas passing through the valve hole 31e increases,
The pressure difference (Pd-Pd ') around 1a increases. When the discharge pressure Pd is larger than the suction pressure Ps under such a differential pressure state, the formula (D) is satisfied, and when the discharge pressure Pd is equal to the suction pressure Ps, the formula (C) is satisfied. The throttle action of the throttle hole 41a is set. Therefore, the valve element 3
When 3 is the maximum opening, the valve 41 is opened when the discharge pressure Pd is larger than the suction pressure Ps, and the valve 41 is closed when the discharge pressure Pd is equal to the suction pressure Ps.

[0032] Curve E ₁ in FIG. 9 is the discharge pressure Pd and the suction pressure Ps
5 shows the control characteristics of the capacity control valve 24b expressed by. The straight line L represents Ps = Pd. Curve E ₁ is Pd> Pd
_In the range of ₀ , it is represented by the following equation (E). _{Ps = P 0 - (Pd-} Pc) S 3 / S 4 ··· (E) provided that the sum of the spring force and the atmospheric pressure P ₀ is a spring 47 which acts on the spring bearing 45, S ₃ is a valve hole 31e , S ₄ is the area of the bellows fitting 45.

When the discharge pressure Pd is in the range of Pd ₀ or more, the suction pressure Ps increases as the discharge pressure Pd decreases. Discharge pressure Pd
Above the curve E ₁ in the range of Pd ₀ or more
Is a region where the valve body 33 is in the closed state, and the lower side is a region where the valve body 33 is in the open state. That is, in the range where the discharge pressure Pd is equal to or higher than Pd ₀ , when the suction pressure Ps becomes higher than the curve E ₁ , the valve element 33 closes the valve hole 31 e, and the suction pressure Ps becomes lower than the curve E _1. Then, the valve element 33 opens the valve hole 31e. By this opening / closing control, the discharge pressure Pd and the suction pressure Ps are changed to a curve E ₁
The capacity control of moving upward is performed. This curve E ₁
Suction pressure of the upper is set suction pressure Ps _0.

[0034] However, a relationship of the curve E ₂ is the discharge pressure Pd and the suction pressure Ps in the range of Pd <Pd ₀ if there is no bypass on-off valve 24b. That is, as the discharge pressure Pd decreases, the flow rate of the refrigerant passing through the valve hole 31e decreases, and the suction pressure Ps also starts to decrease. Therefore, the valve element 33 takes the maximum opening in the range of Pd <Pd ₀ of the discharge pressure Pd and the suction pressure Ps decreases both capacity control by the displacement control valve 24a becomes impossible. Pd <curve E ₂ in the range of Pd ₀ is approaching a straight line L, even slightly discharge the swash plate 15 is at the minimum inclination position, that is, the compression is performed, the external refrigerant while the refrigerant gas is small The circuit 49 circulates.

When the bypass on-off valve 24b is open, the discharge chamber 3b and the swash plate chamber 3a communicate with each other via the bypass passage 36. However, the differential pressure between the discharge pressure Pd, the suction pressure Ps, and the pressure Pc in the crank chamber 2a keeps the relationship of Pd>Pc> Ps although it is small due to the compression. Therefore, if the pressure Pc in the crank chamber 2a is reduced, the swash plate inclination angle increases from the minimum state.

Even when the capacity control by the capacity control mechanism is disabled, the refrigerant gas circulates in the external refrigerant circuit 49 although the amount is small. The circulation results in a frost in the evaporator 52. However, the valve body 41 of the bypass opening / closing mechanism
Is opened under the maximum opening state of the valve body 33. When the valve 41 is opened, the discharged refrigerant gas flows into the suction chamber 3b via the bypass passage 36. Therefore, the discharge pressure Pd in the valve housing 31A becomes substantially equal to the suction pressure Ps, and the valve body 41 is closed again. When the valve body 41 is closed, the discharge pressure Pd in the valve housing 31A becomes larger than the suction pressure Ps again, and the valve body 41 shifts to the open state. That is, when the valve body 33 is in the maximum opening state, the valve body 41
Repeats opening and closing.

The operation of the control valve 24 is summarized as follows. When the solenoid 25 is in the excited state: (1) When Ps ₀ <Ps (the cooling load is very large): both the valve bodies 33 and 41 are closed.

[0038] (2) Ps ₀ ≧ Ps (suction pressure Ps set suction pressure Ps ₀ or less, and if not far removed from the target suction pressure Ps ₀₎ when: the valve element 33 takes the opening corresponding to Ps Then, the valve element 41 is closed.

[0039] (3) Ps ₀ »Ps (smaller than the suction pressure Ps is set suction pressure Ps _0, and if far removed from the target suction pressure Ps ₀₎ when: When Pd ≒ Ps, the valve element 33 is fully open Then, the valve body 41 closes.

When Pd> Ps, the valve body 33 is fully opened,
The valve element 41 opens. When the solenoid 25 is in the demagnetized state, the valve body 33 is fully opened and the valve body 41 is closed when Pd の Ps regardless of the value of the suction pressure Ps. When Pd> Ps, the valve element 33 is fully opened and the valve element 41 is opened.

FIG. 6 corresponds to the condition (1), and FIG. 7 corresponds to the condition (3). FIG. 8 corresponds to Pd> Ps when the solenoid 25 is in the demagnetized state. In FIG.
Is open and dispensing is disabled.

In a capacity control impossible region where both the discharge pressure Pd and the suction pressure Ps decrease, a state of Ps ₀ ≫Ps occurs. When Ps ₀ ≫Ps and the environment is such that the outside air temperature is near the freezing point, the discharged refrigerant gas is supplied to the external refrigerant circuit 49.
Frost is generated in the evaporator 52. However, when the solenoid 25 is energized, the control valve 24 repeatedly opens and closes the valve element 41 based on the pressure relationship in (3). The control valve 24 repeatedly opens and closes the valve element 41 even when the solenoid 25 is demagnetized. Therefore, a state in which the discharged refrigerant gas does not circulate in the external refrigerant circuit 49 occurs intermittently, and the occurrence of frost in the evaporator 52 is prevented.

If the discharged refrigerant gas does not circulate in the external refrigerant circuit 49, the lubricating oil will not flow back into the compressor, and poor lubrication in the compressor will occur. The state in which the discharged refrigerant gas circulates in the external refrigerant circuit 49 intermittently due to the repeated opening and closing of the valve body 41, thereby avoiding poor lubrication in the compressor.

[0044] When the inclination angle of the inclined plate solenoid 25 is a excited state is at a minimum condition, the valve element 33 comes to close the valve hole 31e exceeds preset suction pressure Ps ₀ by cooling load has increased. The set suction pressure Ps _{0 at} this time is a suction pressure at the intersection of the straight line L and an extension line (shown by a dashed line in FIG. 9) of the curve E ₁ . The crank chamber 2a is closed by closing the valve hole 31e.
And the swash plate tilt angle increases from the minimum state.
Further, the valve element 41 closes the valve hole 31f. Therefore, normal capacity control is restored.

In order to increase the inclination angle of the swash plate from the minimum state, that is, to perform the capacity return, the pressure Pc having the relationship of Pd>Pc> Ps may be reduced, but in particular, the rotational speed of the compressor is low. In the case of rotation, the pressure difference between the pressures Pd, Pc, Ps is slight. Therefore, when the swash plate tilt angle starts increasing from the minimum state, if there is a resistance against this, it becomes difficult to increase the tilt angle, and it is difficult to return the capacitance.

The minimum inclination regulating spring 55 biases the swash plate support 14 toward a position where the inclination of the swash plate becomes minimum. Since the pressure difference between the respective pressures Pd, Pc, Ps is small, it is difficult to stably maintain the swash plate inclination at the minimum state without the minimum inclination regulating spring 55. However, the minimum inclination defining spring 55
Of the swash plate support 1 at a position other than the position where the spring force of the
4, the swash plate support 14 is stably held near the minimum tilt position even when the pressure difference between the pressures Pd, Pc, and Ps is small. Therefore, the swash plate inclination does not increase from the minimum state without permission.

If the spring force of the minimum inclination defining spring 55 also acts on the swash plate support 14 at the position where the minimum inclination angle is obtained, the resistance when the swash plate inclination angle starts increasing from the minimum state. Becomes However, in the present embodiment, the natural length of the minimum inclination defining spring 55 is slightly shorter than the interval between the swash plate support 14 at the position where the swash plate 15 has the minimum inclination and the step portion 9a. The spring force of the spring 55 becomes zero with respect to the swash plate support 14 at the position where the swash plate tilt angle is the minimum. Therefore, the minimum inclination regulating spring 55 does not become a resistance when the inclination angle of the swash plate starts to increase from the minimum state, and the capacitance is reliably restored.

Forcibly changing the inclination angle of the swash plate 15 to the minimum is a high-pressure supply to the crank chamber 2a by demagnetizing the solenoid 25. The capacity return is performed by increasing the cooling load or exciting the solenoid 25. The swash plate support 14 is held at the position where the inclination angle of the swash plate 15 is minimized because the pressure P
Due to the differential pressure between d, Pc and Ps and the spring action of the minimum inclination defining spring 55. Therefore, unlike the clutchless compressor disclosed in JP-A-3-143725, which requires an electromagnetic valve for reducing the swash plate inclination to zero and an electromagnetic valve for resetting the swash plate inclination, respectively. There is no increase in the size and weight of the compressor.

The present invention is, of course, not limited to the above embodiment, but may be, for example, the embodiments shown in FIGS. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, a control valve 24A is used instead of the control valve 24 of the first embodiment. This control valve 24
A includes a solenoid 25, a capacity control valve 24a, and a bypass opening / closing valve 24c. As shown in FIGS. 12 and 13, the valve 57 of the bypass opening / closing valve 24c has a spring 5
8 and the discharge pressure Pd are acting in the closing direction,
The spring force of the spring 64 and the suction pressure Ps act on the valve body 57 in the opening direction. The valve body 57 opens the valve hole 59 when the difference between the discharge pressure Pd and the suction pressure Ps falls below a certain value.
This constant value is when the discharge pressure Pd reaches Pd ₀ shown in FIG. Therefore, the bypass valve 24c is connected to the discharge pressure P
When d is equal to or less than Pd ₀ , the open state is maintained, and the occurrence of frost in the evaporator 52 is prevented.

A pressure release control valve 60 is provided on a pressure release passage 1d connecting the crank chamber 2a and the suction chamber 3a.
A spring 62 is provided on the spool valve 61 constituting the pressure release control valve 60.
Spring force is acting. An annular flow channel 61 a is formed on the peripheral surface of the spool valve 61. 10 and 12
As shown in the figure, the flow channel 61a is always arranged at a position where the pressure release passage 1d is throttled by the spring force of the spring 62 acting on the spool valve 61, and the refrigerant gas in the crank chamber 2a is sucked while being throttled. Released into the chamber 3a.

When the solenoid 63 is excited, the spool valve 61 moves toward the solenoid 63 against the spring action of the spring 62. As shown in FIGS. 11 and 13, the flow passage groove 61a substantially cuts the cross section of the pressure release passage 1d. It is arranged in a fully open position. This movement arrangement increases the passage cross-sectional area on the pressure release passage 1d, and the pressure in the crank chamber 2a is rapidly released to the suction chamber 3a. Due to this pressure releasing action, the suction pressure in the suction chamber 3a increases, and the increase in the suction pressure spreads to the suction pressure detection chamber 43 of the capacity control valve 24a. Due to this pressure spread, the valve body 33
Closes the valve hole 31e, and the refrigerant gas flow from the discharge chamber 3b to the crank chamber 2a stops. Therefore, the crank chamber 2a
And the swash plate inclination increases from the minimum inclination.

When the swash plate support 14 is at a position where the swash plate tilt angle is the minimum, the spring receiver 65 is fixed to the peripheral surface of the rotating shaft 9. Is to receive. Therefore, since the spring force of the minimum tilt angle defining spring 55 does not act on the swash plate support 14 at the position where the swash plate is at the minimum tilt angle, the capacity return is accurately performed.

Further, a tension spring that pulls and biases the swash plate support 14 toward the position where the swash plate tilt angle becomes the minimum may be used as the minimum tilt angle defining spring. In this case, the swash plate support 1
It is sufficient that the tension spring has a natural length when the position 4 is at the position where the swash plate tilt angle is the minimum.

[0055]

As described above in detail, according to the present invention , when the inclination angle of the swash plate is the minimum inclination angle, the spring action of the minimum inclination defining spring does not act on the swash plate support. It is possible to achieve an excellent effect that the capacitance can be accurately restored without any problem.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an entire compressor according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a side sectional view in a state where a swash plate tilt angle is in a minimum state.

FIG. 5 is an enlarged sectional view of a main part.

FIG. 6 is an enlarged sectional view of a control valve in a normal displacement control state.

FIG. 7 is an enlarged side sectional view of the control valve in a state where a bypass passage is opened.

FIG. 8 is an enlarged sectional side view of the control valve in a state where the valve body 33 is forcibly changed to a closed position.

FIG. 9 is a graph illustrating a displacement control characteristic based on a discharge pressure and a suction pressure.

FIG. 10 is a side sectional view of the entire compressor showing a second embodiment.

FIG. 11 is a side sectional view of the entire compressor in a state where the passage cross-sectional area of the pressure release passage is increased.

FIG. 12 is an enlarged sectional side view showing a state where the pressure release control valve is narrowing the pressure release passage.

FIG. 13 is an enlarged side sectional view showing a state where the pressure release control valve increases the passage cross-sectional area of the pressure release passage.

[Explanation of symbols]

2a: crank chamber, 3a: suction chamber serving as a suction pressure region, 3
b: discharge chamber serving as a discharge pressure region, 9: rotating shaft, 14: swash plate support, 15: swash plate, 21: minimum inclination defining ring serving as minimum inclination defining means, 22: single-headed piston, 24b: bypass opening / closing valve , 36: bypass passage, 55: minimum inclination defining spring.

──────────────────────────────────────────────────続 き Continued from the front page (72) Inventor Shigeki Kanzaki 2-1-1, Toyota-cho, Kariya-shi, Aichi Prefecture Inside Toyota Industries Corporation (58) Field surveyed (Int. Cl. ⁷ , DB name) F04B 27 / 14

Claims (1)

(57) [Claims] 1. A crank chamber, a suction chamber, a discharge chamber, and each of these
The cylinder bores to connect the chamber to partition formed, rotatably supports the rotary shaft single-headed piston into the cylinder bore to the reciprocal linear movably accommodated to the housing, rotating supported by a rotating shaft
The body as well as fastening, swash plate and tiltably linked to the rotation support, controls the inclination angle of the swash plate by the difference through a single-headed piston between the pressure and the suction pressure in the crank chamber, a discharge pressure region and the crank The pressure in the discharge pressure region is supplied to the crank chamber through a pressure supply passage connecting the chamber, and the pressure in the crank chamber is released to the suction pressure region through a discharge passage connecting the crank chamber and the suction pressure region. In the clutchless one-sided piston type variable displacement compressor that regulates the pressure in the crank chamber, the bypass passage connecting the discharge pressure region and the suction pressure region and the bypass passage can be opened when the swash plate tilt angle is the minimum tilt angle comprises a bypass opening and closing valve, and a minimum inclination angle defines a spring for urging the front Kihasu plate to tilt decreasing direction, the minimum inclination angle defining the spring when the swash plate inclination is minimum inclination was Unishi'm not act on the swash plate Kura Capacity recovery structure in Chiles one piston type variable displacement compressor.