JPH06307338A - Capacity control structure for variable capacity clutchless compressor of single side piston type - Google Patents

Abstract

PURPOSE:To provide a clutchless compressor which can prevent poor performance of lubrication and a large torque variation. CONSTITUTION:The tilting angle of a swash plate 15 supported swingably on a rotary shaft 9 through a support 14 is controlled through adjustment of the pressure in a crank chamber 2a. The discharge refrigerant gas in the discharge chamber 3b is introduced to the crank chamber 2a via a discharge pressure introducing passage 34, control valve 24, and control passage 37, and the refrigerant gas in the crank chamber 2a is forwarded to the suction chamber 3a via a pressure release passage 1b. A pressure release control valve 36 is installed in the pressure release passage 1b and opened and closed in accordance with the magnitude of the discharge pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a crank chamber, a suction chamber,
A discharge chamber and a cylinder bore that connects these chambers are defined and formed, and a swash plate support is slidably supported on a rotary shaft in a housing that accommodates a single-headed piston in a reciprocating linear motion in the cylinder bore. The swash plate is tiltably supported on the body, and the swash plate is tiltably linked to a rotary support fixed to a rotary shaft, and the difference between the pressure in the crank chamber and the suction pressure via a single-head piston causes the swash plate to move. The present invention relates to a displacement control structure of a clutchless one-side piston type variable displacement compressor that controls a tilt angle.

[0002]

2. Description of the Related Art In the variable displacement rocking swash plate compressor disclosed in JP-A-59-150988 and JP-A-61-55380, an external drive source and a rotary shaft of the compressor are provided. No electromagnetic clutch is used to connect and disconnect power transmission. If the electromagnetic clutch is eliminated, it is possible to eliminate the drawback of poor feeling in feeling due to the ON / OFF shock, especially in the vehicle-mounted form, and to reduce the weight and cost of the entire compressor.

In each of the variable displacement type swash plate type compressors disclosed in the above-mentioned publications, the pressure in the crank chamber accommodating the swash plate is rapidly increased to bring the swash plate inclination angle to near 0 °, and the discharge capacity is increased. It is designed to drop the to near zero. The load on the compressor sharply decreases due to the sharp decrease in the discharge capacity. When a compressor is installed in a vehicle, it is desirable to direct all of the vehicle engine output to drive the vehicle when accelerating or climbing a vehicle. In such a case, the load on the compressor can be drastically reduced. Be seen.

[0004]

In such a clutchless compressor, there are problems of frost in the evaporator on the external refrigerant circuit and lubrication in the compressor. When the outside air temperature is near the freezing point, frost may be generated in the evaporator, and under such environmental conditions, the swash plate tilt angle must be brought close to 0 ° to invalidate the discharge. On the contrary, in the discharge disabled state, the circulation of the refrigerant is substantially lost, and thus the poor lubrication in the compressor becomes a problem. Therefore, it is necessary to increase the pressure in the crank chamber and increase the inclination angle of the swash plate at the minimum inclination angle as necessary to restore the capacity to ensure lubrication in the compressor. However, if the swash plate tilt angle becomes too large (that is, the return capacity becomes too large), the torque fluctuation of the compressor becomes too large and the shock due to the torque fluctuation becomes large.

An object of the present invention is to solve the problem of lubrication without increasing the return capacity too much.

[0006]

Therefore, according to the present invention,
When the swash plate inclination is at the minimum state, the pressure supply control means for narrowing the control passage that connects the discharge pressure region and the crank chamber and the pressure release passage that connects the crank chamber and the suction pressure region are interposed to respond to the discharge pressure. And a pressure release control valve for controlling the pressure release is configured, and the pressure release control valve is operated in a direction of closing the pressure release passage as the discharge pressure decreases.

[0007]

When the swash plate tilt angle becomes the minimum tilt angle, the pressure supply passage that connects the discharge pressure region and the crank chamber is closed, and the pressure in the crank chamber decreases. Due to this pressure decrease, the swash plate inclination angle increases, and the pressure supply passage opens. When the pressure supply passage opens, the pressure in the crank chamber rises. When the swash plate inclination angle is near the minimum, the discharge pressure has dropped and the pressure release control valve is closed. Therefore, the pressure in the crank chamber is increased instantaneously, and the swash plate tilt angle does not become too large.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment embodying the present invention will now be described with reference to FIG.
~ It demonstrates based on FIG. As shown in FIG. 1, a front housing 2 is joined to the front end of a cylinder block 1 which is a part of the 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 rotary support 8 is supported by the deep groove ball bearing member 7, and a rotary shaft 9 is fixed to the rotary 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 rotary shaft 9 via the rotary support 8.

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

A spherical swash plate support 14 is slidably supported on the rotary 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 rotary 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, 19 are fixedly attached to the connecting pieces 16, 17. A support arm 8a is provided on the rotary support 8 in a protruding manner. A support pin 20 is rotatably supported by the support arm 8a in a direction perpendicular to the rotary shaft 9. A pair of guide pins 18, 19
Are slidably fitted into both ends of the support pin 20. The support pin 20 on the support arm 8a and the pair of guide pins 18 and 19 are linked to each other, so that the swash plate 15 can move the swash plate support 14
Can be tilted in the axial direction of the rotary shaft 9 and rotatable integrally with the rotary shaft 9. The tilt of the swash plate 15 is due to the slide guide relationship between the support pin 20 and the guide pins 18 and 19,
It is guided by the sliding action of the swash plate support 14 and the supporting action of the swash plate support 14.

The maximum tilt angle of the swash plate 15 is restricted by the contact between the tilt angle control projection 8b of the rotary support 8 and the swash plate 15.
A minimum tilt angle restricting ring 21 is fixedly mounted on the rotary shaft 9, and the minimum tilt angle of the swash plate 15 is restricted by the contact between the minimum tilt angle restricting 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 control ring 21 is slightly larger than 0 °. This minimum tilt angle is made as small as possible so that the tilt angle of the swash plate can be increased from this tilt position, that is, the capacity can be restored.

A single-head piston 22 is housed in a cylinder bore 1a penetrating the cylinder block 1 so as to be connected to the crank chamber 2a. A pair of shoes 23 is fitted in the neck portion 22 a of the one-headed piston 22. Swash plate 1
The peripheral edge portion of the slab 5 enters between both 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 forward and backward reciprocating swing of the single-headed piston 22 via 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, the rear housing 3 has a suction chamber 3a and a discharge chamber 3b defined therein. An intake 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. The refrigerant gas in the suction chamber 3a is sucked into the suction port 4a by the returning movement of the single-headed piston 22.
The suction valve 5a is pushed away from the inside to flow into the cylinder bore 1a. The refrigerant gas flowing into the cylinder bore 1a is discharged from the discharge port 4b to the discharge chamber 3b by pushing the discharge valve 5b away from the discharge port 4b by the forward movement of the single-headed piston 22. Discharge valve 5b
Is brought into contact with the retainer 6a on the retainer forming plate 6 to regulate the opening.

The stroke of the single-headed piston 22 changes depending on 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 tilt angle of the swash plate 15 that affects the compression capacity changes. The pressure in the crank chamber 2a is controlled by the control valve 24 attached to the rear housing 3. Crank chamber 2a and suction chamber 3a
Are connected to each other by a pressure release passage 1b.

The internal structure of the control valve 24 will be described with reference to FIGS. 5 and 6. Bobbin 26 supporting solenoid 25
A guide cylinder 27 is fixed to the hollow part of the hollow cylinder, and a fixed iron core 28 is accommodated and fixed in the guide cylinder 27. A movable iron core 29 is housed in the guide cylinder 27 so as to be able to come into contact with 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 biased in a direction away from the fixed iron core 28 by the spring action of the valve opening forced spring 30.

A valve housing 31 is coupled and fixed to the bobbin 26 via a connecting member 32, and a spherical valve element 33 is accommodated in the valve housing 31. The valve housing 31 is provided with a discharge pressure introducing port 31a, a suction pressure introducing port 31b and a control port 31c. The discharge pressure introducing port 31a communicates with the discharge chamber 3b through the discharge pressure introducing passage 34. Suction pressure introduction port 31
b communicates with the suction chamber 3a through the suction pressure introducing passage 35, and the control port 31c communicates with the crank chamber 2a through the control passage 37.

The control passage 37 passes through the inside of the rotary shaft 9,
The outlet 37a is open on the peripheral surface of the rotating shaft 9. Figure 1
When the tilt angle of the swash plate 15 is larger than the minimum tilt angle, the outlet 37a is exposed to the crank chamber 2a. As shown in FIG. 4, when the inclination of the swash plate 15 reaches the minimum inclination, the outlet 37
a is shielded by the swash plate support 14. The swash plate 15 and the swash plate support 14 constitute pressure supply control means for opening and closing the control passage 37.

A return spring 39 and a valve support seat 40 are interposed between the spring receiver 38 in the valve housing 31 and the valve body 33, and the valve body 33 moves the return spring 39 in the direction of closing the valve hole 31d. Receives spring action.

A bellows fitting 44 is housed in the suction pressure detecting chamber 43 communicating with the suction pressure introducing port 31b in a state of being fixed to the movable iron core 29. The bellows fitting 44 and the spring bearing 45 are connected by a bellows 46, and a spring 47 is interposed between the bellows fitting 44 and the spring bearing 45.

A transmission rod 48 is fixedly attached to the spring receiver 45, and the tip of the transmission rod 48 is in contact with the valve element 33. At the lower part of the rear housing 3, the pressure release control valve 3 is provided on the pressure release passage 1b.
6 is provided. A part of the accommodating chamber of the spool valve 41 forming the pressure release control valve 36 is partitioned into a pressure receiving chamber 42, and the pressure receiving chamber 42 communicates with the discharge chamber 3b via a pressure receiving passage 53. The spring force of the spring 54 acts on the spool valve 41. This acting direction is a direction facing the pressure of the pressure receiving chamber 42. The spool valve 41 is displaced by the opposition of the pressure of the pressure receiving chamber 42 and the spring force of the spring 54. An annular passage groove 38a is formed on the circumferential surface of the spool valve 41.
The flow path groove 38a communicates with or blocks the pressure release passage 1b according to the displacement of the spool valve 41. The spool valve 41 is the flow path groove 38.
When it is placed in an open position that connects a with the pressure release passage 1b,
The crank chamber 2a and the suction chamber 3a communicate with each other. When the spool valve 41 is arranged at the closed position that blocks the flow passage groove 38a and the pressure release passage 1b, the crank chamber 2a and the suction chamber 3a are blocked.

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

The solenoid 25 is adapted to be excited and demagnetized by turning on and off an air conditioner operation switch (not shown). In the state of FIG. 1, the air conditioner operation switch is turned off.
N, the solenoid 25 is in an excited state. In the energized state of the solenoid 25, as shown in FIG.
The fixed iron core 28 against the spring action of the valve opening forced spring 30.
Is adsorbed on.

When the solenoid 25 is excited, the bellows 46 is displaced according to the fluctuation of the suction pressure Ps introduced from the suction pressure introducing port 31b, and this displacement is transmitted.
It is transmitted to the valve element 33 via 8. Intake pressure Ps is spring 4
Below the set suction pressure Ps ₀ determined by the spring force of 7,
In addition, when the suction pressure Ps is high (the cooling load is large) in a range that is not largely separated from the set suction pressure Ps ₀ , the valve opening degree of the valve element 33 decreases. Also, the pressure release control valve 3
The spool valve 41 of No. 6 is in the open position by the discharge pressure in the pressure receiving chamber 42, and the refrigerant gas in the crank chamber 2a is in the pressure release passage 1
It flows out to the suction chamber 3a via b. Therefore, when the valve opening degree of the valve element 33 is reduced, the pressure in the crank chamber 2a is reduced and the swash plate inclination angle is increased. That is, the discharge capacity becomes large. On the contrary, the suction pressure Ps is low (the cooling load is small).
In this case, the valve opening of the valve element 33 becomes large. Therefore, the pressure in the crank chamber 2a rises and the swash plate inclination angle becomes smaller.
That is, the discharge capacity becomes small.

Therefore, the tilt angle of the swash plate 15 is restricted between the maximum tilt position where it contacts the tilt restricting projection 8b and the minimum tilt position where the swash plate support 14 contacts the minimum tilt restricting ring 21. That is, the discharge capacity is controlled within this tilt angle range of the swash plate 15.

When the solenoid 25 is demagnetized by turning off the air conditioner operating switch, the movable iron core 29 is separated from the fixed iron core 28 by the spring action of the valve opening forcing spring 30 as shown in FIG. To do. In this maximum open state, the discharge refrigerant gas in the discharge chamber 3b passes through the discharge pressure introducing passage 34, the discharge pressure introducing port 31a, the valve hole 31d, the control port 31c and the control passage 37, and the crank chamber 2a.
And the pressure in the crank chamber 2a is rapidly increased. Therefore, the swash plate 15 immediately shifts to the minimum tilt angle. Since the minimum tilt angle is not zero, a slight amount of ejection, that is, compression is performed even in the minimum tilt state. Due to this compression, the tilt angle of the swash plate 15 can be restored. However, this minimum tilt angle state is a substantially discharge ineffective state in which frost is not generated in the evaporator 52.

In an environment where the outside temperature is near the freezing point, there is almost no cooling load, and the suction pressure Ps is the set suction pressure P.
It is a low pressure value that is far from s ₀ . Therefore, the valve body 33 maintains the maximum opening degree, and the swash plate inclination angle approaches the minimum inclination angle.

When the inclination angle of the swash plate is minimized and the outlet 37a is shielded, the pressure in the crank chamber 2a is reduced and the swash plate 15 is depressed.
Increases again. When the swash plate tilt angle increases, the discharge capacity increases, and the discharged refrigerant gas circulates in the external refrigerant circuit 49.
Therefore, the lubricating oil flows back into the compressor to ensure lubrication. When the outlet 37a is exposed to the crank chamber 2a, the pressure in the crank chamber 2a increases and the swash plate 15 shifts to the minimum tilt angle again. Both the defective lubrication and the occurrence of frost are eliminated by alternately repeating the minimum inclination state of the discharge disabled state and the inclination state of the discharge enabled state.

When the swash plate tilt angle is increased from the minimum swash plate tilt angle in order to ensure lubrication, if the swash plate tilt angle becomes too large, the torque fluctuation in the compressor becomes large, causing an unpleasant shock. The pressure release control valve 36 in the present embodiment is configured to open and close the pressure release passage 1b according to the fluctuation of the discharge pressure Pd. The discharge pressure Pd in the case of the normal capacity control in which the cooling load is normal holds the spool valve 41 in the open position against the spring force of the spring 54. However, when there is almost no cooling load, the spool valve 41 is placed in the closed position due to the force relationship between the discharge pressure Pd and the spring force of the spring 54 when the swash plate tilt angle is near the minimum tilt angle. When the spool valve 41 is placed in the closed position, the pressure release passage 1b is closed, and the pressure increase in the crank chamber 2a when the swash plate 15 increases from the minimum tilt angle to ensure lubrication closes the pressure release passage 1b. It is sharp because of the condition. This sudden pressure increase prevents a large return of the swash plate tilt angle, and a large torque fluctuation does not occur. Therefore, no unpleasant shock due to large torque fluctuations occurs.

[0029]

As described above in detail, according to the present invention, the pressure release control valve interposed on the pressure release passage connecting the crank chamber and the suction pressure region is provided with the pressure release passage as the discharge pressure decreases. Since the operation is performed in the closing direction, the capacity recovery for ensuring lubrication does not become too large, and the excellent effect that the torque fluctuation due to the capacity recovery can be suppressed is exhibited.

[Brief description of 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.

FIG. 4 is a side sectional view in which the swash plate inclination angle is in a minimum state.

FIG. 5 is a side sectional view of the control valve in an excited state.

FIG. 6 is a side sectional view of the control valve in a demagnetized state.

[Explanation of symbols]

1b ... Pressure release passage, 2a ... Crank chamber, 3a ... Suction chamber serving as suction pressure region, 3b ... Discharge chamber serving as discharge pressure region, 9 ... Rotating shaft, 14 ... Swash plate support member constituting pressure supply control means,
15 ... Swash plate, 22 ... Single-headed piston, 36 ... Pressure release control valve,
37 ... Control passage.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ken Mizuto 2-1-1 Toyota-cho, Kariya city, Aichi stock company Toyota Industries Corp.

Claims (1)

[Claims] 1. A swash plate support on a rotating shaft in a housing that defines a crank chamber, a suction chamber, a discharge chamber, and a cylinder bore connecting these chambers, and accommodates a single-head piston in a reciprocating linear motion in the cylinder bore. Is slidably supported, the swash plate is tiltably supported on the swash plate support, and the swash plate is tiltably linked to the rotary support fixed to the rotary shaft to reduce the pressure in the crank chamber and the suction pressure. In the clutchless one-sided piston type variable displacement compressor that controls the tilt angle of the swash plate by the difference via the single-headed piston, when the swash plate tilt angle is at the minimum state, the pressure supply that narrows the control passage that connects the discharge pressure region and the crank chamber A control means and a pressure release control valve that is interposed on a pressure release passage that connects the crank chamber and the suction pressure region and that controls the pressure release in response to the discharge pressure. aisle Capacity control structure of a clutchless one piston type variable displacement compressor so as to operate the pressure release valve in the closing direction.