JPH08159022A - Variable capacity type compressor - Google Patents

Abstract

PURPOSE: To reduce power consumption while avoiding lubricating shortage in a cluchless variable capacity compressor. CONSTITUTION: The intake passage 26 of the center part of a rear housing 3 is provided on the extending line of a rotary shaft 9 for supporting a swash plate 15. The shut-out surface 21-3 of a shut-out body 21 abuts on a positioning surface 27 so as to shut out the intake passage 26. A throttle body 20 is protruded on the shut-out body 21. The circumference of the throttle body 20 consists of a first taper circumferential surface 20-1, a second taper circumferential surface 20-2, and a straight circumferential surface 20-3. The diameter of the straight circumferential surface 20-3 is formed slightly smaller than the diameter of the intake passage 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention accommodates a piston in a cylinder bore so that the piston can reciprocate linearly, and the inclination angle of the swash plate is dependent on the difference between the suction pressure and the pressure in the crank chamber that houses the swash plate. The present invention relates to a clutchless variable displacement compressor that controls the pressure in the crank chamber by supplying the pressure in the discharge chamber to the crank chamber and releases the pressure in the crank chamber to the suction chamber through the pressure release passage. It is a thing.

[0002]

2. Description of the Related Art A variable displacement compressor disclosed in Japanese Patent Laid-Open No. 3-37378 uses an electromagnetic clutch for connecting and disconnecting power transmission between an external drive source and a rotary shaft of the compressor. Absent. 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 such a clutchless compressor, there are problems in the discharge capacity when cooling is not necessary and the generation of frost in the evaporator on the external refrigerant circuit. If cooling is not necessary or if frost may be generated, the circulation of the refrigerant on the external refrigerant circuit may be stopped. In the compressor disclosed in Japanese Patent Laid-Open No. 3-37378, the circulation of refrigerant on the external refrigerant circuit is stopped by stopping the flow of refrigerant gas from the external refrigerant circuit into the suction chamber. The inflow of refrigerant gas from the external refrigerant circuit into the suction chamber is controlled by the demagnetization of the electromagnetic on-off valve.

When the flow of the refrigerant gas from the external refrigerant circuit to the suction chamber in the compressor is stopped, the pressure in the suction chamber is lowered and the capacity control valve sensitive to the pressure in the suction chamber is fully opened. Due to this full opening, the refrigerant gas discharged from the discharge chamber flows into the crank chamber, and the pressure in the crank chamber rises. Further, the suction pressure in the cylinder bore also decreases due to the pressure decrease in the suction chamber. Therefore, the difference between the pressure in the crank chamber and the suction pressure in the cylinder bore becomes large, and the swash plate tilt angle shifts to the minimum tilt angle to minimize the discharge capacity. When the discharge capacity becomes the minimum, the load torque in the compressor becomes the minimum, and power loss when cooling is unnecessary can be avoided.

The crank chamber and the suction chamber communicate with each other through an outflow hole. When the refrigerant gas is stopped from flowing from the external refrigerant circuit into the suction chamber in the compressor, the refrigerant gas discharged from the cylinder bore into the discharge chamber flows into the crank chamber via the capacity control valve in the fully open state. The refrigerant gas in the crank chamber flows out to the suction chamber via the outflow hole, and the refrigerant gas flowing out to the suction chamber is sucked into the cylinder bore during the suction stroke.
That is, in the state where the refrigerant gas flow from the external refrigerant circuit to the suction chamber in the compressor is stopped, the refrigerant gas in the compressor circulates in the order of the cylinder bore, the discharge chamber, the crank chamber, the suction chamber, and the cylinder bore, and the circulating refrigerant gas The lubricating oil flowing together lubricates the inside of the compressor.

When the flow of the refrigerant gas from the external refrigerant circuit into the suction chamber in the compressor is restarted, the pressure in the suction chamber rises and the capacity control valve sensitive to the pressure in the suction chamber closes. Due to this transition to the closed state, the refrigerant gas is prevented from flowing into the crank chamber from the discharge chamber, and the pressure in the crank chamber decreases. Further, the suction pressure in the cylinder bore also rises due to the rise in the pressure in the suction chamber. Therefore, the difference between the pressure in the crank chamber and the suction pressure in the cylinder bore becomes small, and the swash plate tilt angle shifts to the maximum tilt angle side.

[0007]

The minimum tilt angle of the swash plate that provides the minimum discharge capacity should be as small as possible in order to reduce power consumption. However, the setting of the minimum inclination of the swash plate involves the problem of lubrication in the compressor.

The refrigerant discharged from the compressor to the external refrigerant circuit exchanges heat with the condenser and the evaporator on the external refrigerant circuit and returns to the compressor. The lubricating oil inside the compressor flows out to the external refrigerant circuit together with the refrigerant gas flowing out of the compressor, and the lubricating oil flowing out to the external refrigerant circuit flows back into the compressor together with the refrigerant gas. However, in order to recirculate the lubricating oil flowing out to the external refrigerant circuit into the compressor, the refrigerant flow rate in the external refrigerant circuit needs to be a predetermined amount or more. The refrigerant flow rate depends on the swash plate tilt angle, and when the swash plate tilt angle cannot bring about the predetermined amount of the refrigerant flow rate, only the refrigerant gas flows back into the compressor. Since the lubricating oil in the compressor continues to flow out to the external refrigerant circuit together with the refrigerant gas, unless the lubricating oil flows back from the external refrigerant circuit into the compressor, the inside of the compressor falls into insufficient lubrication. Therefore, when the swash plate tilt angle is slightly larger than the minimum tilt angle of the swash plate in the compressor disclosed in Japanese Patent Laid-Open No. 3-37378, the refrigerant flow rate must reach the flow rate required to recirculate the lubricating oil. That is, the minimum tilt angle of the swash plate must be set to the minimum tilt angle required for the circulation of the lubricating oil.

An object of the present invention is to reduce power consumption while avoiding insufficient lubrication in a variable displacement compressor.

[0010]

To this end, in the invention of claim 1, the minimum tilt angle defining means for defining the minimum tilt angle of the swash plate so as to bring about a non-zero discharge capacity, and the refrigerant from the external refrigerant circuit to the suction pressure region. A variable displacement compressor is configured with a throttle body that throttles a passage cross-sectional area in a suction passage for introducing gas in association with tilting of the swash plate, and the passage cutoff is performed before the tilt angle of the swash plate reaches a minimum tilt angle. The area was reduced, and then the state where the passage cross-sectional area was squeezed to a constant value was continued, and then the inclination angle of the swash plate was changed to the minimum inclination angle.

According to the second aspect of the present invention, the minimum inclination angle defining means for defining the minimum inclination angle of the swash plate so as to provide a discharge capacity which is not zero, and the external refrigerant circuit to the suction pressure region in association with the inclination of the swash plate. Switching operation of the blocking body, which is switched between a position where the refrigerant gas cannot be introduced and an open position where it can be introduced, and a passage cross-sectional area in the suction passage for introducing the refrigerant gas from the external refrigerant circuit to the suction pressure region. A clutchless variable displacement compressor is provided with a throttle body that narrows in conjunction with, and the passage cross-sectional area is reduced before the inclination angle of the swash plate reaches the minimum inclination angle, and then the passage cross-sectional area is made constant. The tilt angle of the swash plate is changed to the minimum tilt angle after the squeezed state is continued.

According to the third aspect of the invention, the suction passage is formed on an extension of the moving path of the throttle body. In the invention of claim 4, the throttle body is made a part of the blocking body, and the throttle body is made to enter the suction passage to reduce the passage cross-sectional area in the suction passage.

According to a fifth aspect of the present invention, the suction passage is throttled by the diaphragm peripheral surface of the diaphragm body, and the tapered peripheral surface inclined with respect to the moving path of the diaphragm body is parallel to the moving path.
Further, the diaphragm peripheral surface is constituted by a straight peripheral surface continuous with the tapered peripheral surface, and the diaphragm action by the diaphragm peripheral surface due to the decrease of the inclination angle of the swash plate shifts from the diaphragm effect of the tapered peripheral surface to the diaphragm effect of the straight peripheral surface. I did it.

According to a sixth aspect of the present invention, the first taper peripheral surface and the second taper peripheral surface continuous with the first taper peripheral surface constitute the taper peripheral surface, and the inclination of the second taper peripheral surface is the first taper. It is made smaller than the inclination of the peripheral surface, and the diaphragm action by the diaphragm peripheral surface due to the decrease of the inclination angle of the swash plate shifts from the diaphragm effect of the first tapered peripheral surface to the diaphragm effect of the second tapered peripheral surface.

[0015]

According to the first aspect of the invention, when the inclination angle of the swash plate is toward the minimum inclination angle, the throttle body starts to reduce the passage cross-sectional area in the suction passage before the inclination angle of the swash plate reaches the minimum inclination angle, and this passage disconnection occurs. The area decreases as the inclination of the swash plate decreases. Then, the swash plate reaches the minimum inclination angle after the diaphragm body continues to squeeze the passage cross-section area constant. In the state where the passage cross-sectional area is constantly throttled, if the constant throttle state is set so that the flow rate of the refrigerant discharged from the compressor to the external refrigerant circuit is not accompanied by the outflow of the lubricating oil from the compressor, the lubricating oil Even if there is no recirculation, the lubricating oil in the compressor will not flow out. Therefore, insufficient lubrication in the compressor does not occur. Further, since the minimum inclination angle of the swash plate can be reduced to an inclination angle corresponding to the flow rate of the refrigerant that cannot recirculate the lubricating oil, power consumption is also reduced.

According to the second aspect of the invention, when the inclination angle of the swash plate is approaching the minimum inclination angle, the inclination of the swash plate is transmitted to the blocking body. This tilt transmission causes the blocking body to move from the open position to the closed position. Before the tilt angle of the swash plate reaches the minimum tilt angle, the diaphragm body narrows the passage cross-sectional area to a constant state. Then, when the blocking body changes from the open position to the closed position, the refrigerant circulation is blocked, and the tilt angle of the swash plate becomes the minimum tilt angle.

According to the third aspect of the invention, since the suction passage is on the extension line of the movement path of the throttle body, it is easy to properly set the degree of throttling of the passage cross-sectional area in the suction passage. According to the invention of claim 4, the diaphragm body and the blocking body are integrated, and it is easy to match the switching operation of the blocking body and the diaphragm operation of the diaphragm body.

According to the fifth aspect of the invention, when the inclination angle of the swash plate is toward the minimum inclination angle, the tapered peripheral surface gradually decreases the passage cross-sectional area of the suction passage, and then the straight peripheral surface passes the suction passage. Continue to reduce the cross-sectional area to a constant state. Therefore, the fluctuation of the load torque becomes slow.

In the sixth aspect of the invention, when the swash plate inclination angle is small, the second tapered peripheral surface gradually reduces the passage cross-sectional area of the suction passage. Since the inclination of the second taper peripheral surface is smaller than that of the first taper peripheral surface, the change of the cross sectional area of passage of the second taper peripheral surface due to the restriction is due to the change of the cross sectional area of passage of the first tapered peripheral surface due to the restriction. Is slower than the change. Therefore, the change of the passage cross-sectional area when the throttle body is narrowing the suction passage becomes slow in the state where the swash plate inclination angle is small, and the change of the load torque is slow.

[0020]

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 FIGS. 1 and 4, a front housing 2 is joined to the front end of the cylinder block 1. At the rear end of the cylinder block 1, a rear housing 3 is provided with a valve plate 4, a valve forming plate 5A,
5B and the retainer forming plate 6 are joined and fixed. A rotary shaft 9 is rotatably supported between the front housing 2 forming the crank chamber 2-1 and the cylinder block 1. The front end of the rotary shaft 9 is the crank chamber 2
-1 is projected to the outside, and the pulley 1 is attached to this protruding end.
0 is fixed. The pulley 10 is operatively connected to the vehicle engine via a belt 11. The pulley 10 is supported by the front housing 2 via an angular bearing 7. The front housing 2 receives both the thrust load and the radial load acting on the pulley 10 via the angular bearing 7.

The front end of the rotary shaft 9 and the front housing 2
A lip seal 12 is interposed between and. The lip seal 12 prevents pressure leak in the crank chamber 2-1.
A rotary support 8 is fixed to the rotary shaft 9, and a swash plate 15 is supported so as to be slidable and tiltable in the axial direction of the rotary shaft 9. As shown in FIG. 2, connecting pieces 16 and 17 are fixed to the swash plate 15. A pair of guide pins 18, 19 are fixedly attached to the connecting pieces 16, 17. Guide balls 18-1 and 19-1 are provided at the tips of the guide pins 18 and 19.
Are formed. A support arm 8-1 is projectingly provided on the rotary support 8, and a pair of guide holes 8 are provided in the support arm 8-1.
-2, 8-3 are formed. The guide balls 18-1 and 19-1 are slidably fitted in the guide holes 8-2 and 8-3.
The swash plate 15 can be tilted in the axial direction of the rotary shaft 9 and can rotate integrally with the rotary shaft 9 by the linkage between the support arm 8-1 and the pair of guide pins 18 and 19. The tilting of the swash plate 15 is
It is guided by the slide guide relationship between the guide holes 8-2, 8-3 and the guide balls 18-1, 19-1 and the slide support action of the rotary shaft 9. The radial center of the swash plate 15 is the cylinder block 1.
Moving to the side, the tilt angle of the swash plate 15 decreases.

An inclination reducing spring 41 is interposed between the rotary support 8 and the swash plate 15. The tilt reducing spring 41 biases the swash plate 15 in a direction to decrease the tilt angle of the swash plate 15. The maximum tilt angle of the swash plate 15 is restricted by the contact between the tilt angle control protrusion 8-4 of the rotary support 8 and the swash plate 15.

A housing hole 1 is provided at the center of the cylinder block 1.
3 penetrates in the direction of the axis L of the rotating shaft 9, and the housing hole 1
A tubular blocking body 21 is slidably accommodated in the inside of the housing 3. The blocking body 21 is composed of a large diameter portion 21-1 and a small diameter portion 21-2. The step between the large diameter portion 21-1 and the small diameter portion 21-2 and the housing hole 1
A suction passage opening spring 24 is interposed between the end surface 3 and the end surface. The suction passage opening spring 24 urges the blocking body 21 toward the swash plate 15 side.

The rear end of the rotary shaft 9 is inserted in the cylinder of the blocking body 21. A radial bearing 25 is fitted and supported on the inner peripheral surface of the large diameter portion 21-1. The radial bearing 25 is prevented by the circlip 14 attached to the inner peripheral surface of the large diameter portion 21-1 from the blocking body 21 coming off from the inside of the cylinder. The rear end of the rotary shaft 9 has a radial bearing 2
It is supported by the peripheral surface of the accommodating hole 13 via the shield member 5 and the shield 21. The radial bearing 25 can slide on the rotating shaft 9.

In the center of the rear housing 3, the suction passage 2 is provided.
6 is formed. The suction passage 26 is on an extension line of the rotating shaft 9 which is a movement path of the blocking body 21. As shown in FIGS. 3 and 7, the suction passage 26 has a circular cross-sectional shape, and the center of the cross-section circle of the suction passage 26 is on the axis L of the rotating shaft 9.
The suction passage 26 communicates with the accommodation hole 13,
A positioning surface 27 is formed around the opening of the suction passage 26 on the side. The positioning surface 27 is on the annuloplasty plate 5A. The blocking surface 21-3 on the small diameter portion 21-2 of the blocking body 21 can contact the positioning surface 27. When the blocking surface 21-3 comes into contact with the positioning surface 27, the blocking body 21 moves to the swash plate 15.
The movement in the direction away from is restricted.

A throttle body 20 is integrally formed at the end of the small diameter portion 21-2. As shown in FIGS. 5 and 6, the diaphragm body 20.
The peripheral surface 20-0 includes a first tapered peripheral surface 20-1 on the tip side, a second tapered peripheral surface 20-2 on the middle side, and a straight peripheral surface 20-3 on the base end side. The inclination of the second tapered peripheral surface 20-2, that is, the inclination of the generatrix of the tapered peripheral surface 20-2 with respect to the axis L, is the inclination of the first tapered peripheral surface 20-1, that is, the taper peripheral surface 20-1 with respect to the axis L. It is smaller than the slope of the bus. The generatrix of the straight peripheral surface 20-3 is parallel to the axis L. First taper peripheral surface 20-1, second taper peripheral surface 2
0-2 and straight peripheral surface 20-3, diaphragm peripheral surface 20-0
The center of the section circle is on the axis L of the rotating shaft 9. The suction passage 26 is on an extension of the movement path of the throttle body 20.

The diameter of the straight peripheral surface 20-3 is the suction passage 26.
The diameter of the cross section is slightly smaller than the diameter of the cross section circle, and as shown in FIGS. 4 and 6, the throttle body 20 can entirely enter the suction passage 26. When the throttle body 20 completely enters the suction passage 26, the blocking surface 21-3 contacts the positioning surface 27, and when the blocking surface 21-3 contacts the positioning surface 27, the suction passage 26 is completely blocked. . When the throttle body 20 is in the suction passage 26, there is a slight gap between the throttle peripheral surface 20-0 of the throttle body 20 and the peripheral surface of the suction passage 26.

A thrust bearing 28 is slidably supported on the rotary shaft 9 between the swash plate 15 and the blocking body 21. As the swash plate 15 moves toward the blocking body 21, the tilting of the swash plate 15 is transmitted to the blocking body 21 via the thrust bearing 28. By this tilt transmission, the blocking body 21 moves toward the positioning surface 27 side against the spring force of the suction passage opening spring 24, and the blocking surface 21-3 abuts on the positioning surface 27. The rotation of the swash plate 15 is prevented from being transmitted to the blocking body 21 due to the presence of the thrust bearing 28. When the blocking body 21 rotates, the load torque in the compressor increases.
In particular, the load torque is large when the blocking surface 21-3 of the blocking body 21 is in contact with the positioning surface 27. The thrust bearing 28 prevents such an increase in load torque.

A single-headed piston 22 is housed in a cylinder bore 1-1 penetrating the cylinder block 1. The rotational movement of the swash plate 15 is transmitted through the shoe 23 to the single-headed piston 2
It is converted into two back-and-forth reciprocating swings, and the single-headed piston 22 moves back and forth in the cylinder bore 1-1.

As shown in FIGS. 1 and 3, the rear housing 3 has a suction chamber 3-1 and a discharge chamber 3-2 defined therein. An intake port 4-1 and a discharge port 4-2 are formed on the valve plate 4. A suction valve 5-1 is formed on the valve forming plate 5A, and a discharge valve 5-2 is formed on the valve forming plate 5B. The refrigerant gas in the suction chamber 3-1 is sucked into the suction port 4-1 by the returning movement of the single-headed piston 22.
, The suction valve 5-1 is pushed away and flows into the cylinder bore 1-1. The refrigerant gas flowing into the cylinder bore 1-1 is discharged from the discharge port 4-2 to the discharge chamber 3-2 by pushing the discharge valve 5-2 away from the discharge port 4-2 by the forward movement of the single-headed piston 22. Discharge valve 5-2
Is brought into contact with the retainer 6-1 on the retainer forming plate 6 to regulate the opening.

A thrust bearing 29 is interposed between the rotary support 8 and the front housing 2. The thrust bearing 29 receives a compression reaction force acting on the rotary support 8 from the cylinder bore 1-1 via the single-headed piston 22, the shoe 23, the swash plate 15, the connecting pieces 16 and 17, and the guide pins 18 and 19.

The suction chamber 3-1 is provided with a housing hole 13 through a through hole 4-3.
Is in communication with. When the blocking surface 21-3 comes into contact with the positioning surface 27, the through hole 4-3 is blocked from the suction passage 26. A passage 30 is formed in the rotary shaft 9. The inlet 30-1 of the passage 30 is opened to the crank chamber 2-1 near the lip seal 12, and the outlet 30-2 of the passage 30 is opened to the cylinder of the blocking body 21. As shown in FIG. 1 and FIG. 5, a pressure release port 21-4 is provided through the peripheral surface of the blocking body 21. Release port 2
1-4 communicates the inside of the cylinder of the blocking body 21 with the housing hole 13.

As shown in FIG. 1, the discharge chamber 3-2 and the crank chamber 2-1 are connected by a pressure supply passage 31. An electromagnetic opening / closing valve 32 is provided on the pressure supply passage 31. The valve body 34 closes the valve hole 32-1 by exciting the solenoid 33 of the electromagnetic opening / closing valve 32. When the solenoid 33 is demagnetized, the valve element 34 opens the valve hole 32-1. That is, the electromagnetic opening / closing valve 32 is the pressure supply passage 31 that connects the discharge chamber 3-2 and the crank chamber 2-1.
Open and close.

A suction passage 26 for introducing the refrigerant gas into the suction chamber 3-1 and a discharge port 1-2 for discharging the refrigerant gas from the discharge chamber 3-2.
And are connected by an external refrigerant circuit 35. A condenser 36, an expansion valve 37 and an evaporator 38 are provided on the external refrigerant circuit 35. The expansion valve 37 is a temperature-type automatic expansion valve that controls the refrigerant flow rate according to the fluctuation of the gas temperature on the outlet side of the evaporator 38. A temperature sensor 39 is installed near the evaporator 38. The temperature sensor 39 detects the temperature in the evaporator 38, and the detected temperature information is sent to the control computer C.

The solenoid 33 of the electromagnetic opening / closing valve 32 is subjected to the excitation / demagnetization control of the control computer C. The control computer C controls the demagnetization of the solenoid 33 based on the detected temperature information obtained from the temperature sensor 39. The control computer C commands the demagnetization of the solenoid 33 when the detected temperature becomes equal to or lower than the set temperature under the ON state of the air conditioner operation switch 40. The temperature below the set temperature reflects the situation in which frost is likely to occur in the evaporator 38. Further, the control computer C demagnetizes the solenoid 33 by turning off the air conditioner operation switch 40.

In the state shown in FIGS. 1 and 5, the solenoid 33 is in the excited state and the pressure supply passage 31 is closed.
Therefore, the high pressure refrigerant gas is not supplied from the discharge chamber 3-2 to the crank chamber 2-1. In this state, the refrigerant gas in the crank chamber 2-1 only flows out to the suction chamber 3-1 through the passage 30 and the pressure release port 21-4, and the pressure in the crank chamber 2-1 is equal to that of the suction chamber 3. It approaches the low pressure in -1, that is, the suction pressure. Therefore, the swash plate 15 is urged in the tilt increasing direction.
The tilt angle of the swash plate 15 is maintained at the maximum tilt angle, and the discharge capacity is maximized. Refrigerant gas in the crank chamber 2-1 is lip seal 1
Since it passes through the inlet 30-1 in the vicinity of 2, the lubricating oil flowing together with the refrigerant gas enhances lubrication and sealing between the lip seal 12 and the rotating shaft 9.

When the swash plate 15 maintains the maximum inclination angle and the discharge action is performed in the state where the cooling load is small, the evaporator 38 is operated.
The temperature at is decreasing so as to approach the temperature at which frost is generated. The temperature sensor 39 sends information on the temperature detected by the evaporator 38 to the control computer C, and when the detected temperature falls below the set temperature, the control computer C commands the demagnetization of the solenoid 33. When the solenoid 33 is demagnetized, the pressure supply passage 31 opens, and the discharge chamber 3-2 and the crank chamber 2-1 communicate with each other. Therefore, the high-pressure refrigerant gas in the discharge chamber 3-2 is supplied to the crank chamber 2-1 via the pressure supply passage 31, and the pressure in the crank chamber 2-1 becomes high. The tilt angle of the swash plate 15 shifts to the minimum tilt angle due to the pressure increase in the crank chamber 2-1.

As the inclination angle of the swash plate 15 decreases from the maximum inclination angle, the blocking member 21 moves along the rotating shaft 9 toward the suction passage 26 side while contracting and deforming the suction passage opening spring 24. Then, the throttle body 20 enters into the suction passage 26. When the throttle body 20 completely enters the suction passage 26, the blocking surface 21-3 contacts the positioning surface 27, and when the blocking surface 21-3 contacts the positioning surface 27, the suction passage 26 is completely blocked. .

Further, the swash plate 15 similarly shifts to the minimum tilt angle by a demagnetization command of the solenoid 33 of the control computer C based on the OFF signal of the air conditioner operation switch 40.

The curve E in the graph of FIG. 8 represents the change in the passage cross-sectional area in the suction passage 26 over the entire range from the maximum swash plate tilt angle state to the minimum swash plate tilt angle state, that is, the maximum discharge volume range. In the straight line portion E ₁ , the throttle body 20 has the suction passage 26.
The area S ₀ surrounded by the outlet peripheral edge 26-1 of the suction passage 26 in the state of being separated from is shown. That is, at this time, the tip peripheral edge of the throttle body 20 and the outlet peripheral edge 26-1 of the suction passage 26 are
The cross-sectional area of passage between and is greater than or equal to the cross-sectional area of passage S ₀ of the main body of the suction passage 26. The inclined line portion E ₂ represents the passage cross-sectional area between the tip peripheral edge of the throttle body 20 and the outlet peripheral edge 26-1 of the suction passage 26 when the throttle body 20 is separated from the suction passage 26. The inclined line portion E ₃ represents the cross-sectional area of passage when the first tapered peripheral surface 20-1 enters the suction passage 26. The inclined line portion E ₄ represents the cross-sectional area of passage when the second tapered peripheral surface 20-2 enters the suction passage 26. The straight line portion E ₅ represents the cross-sectional area of passage when the straight peripheral surface 20-3 enters the suction passage 26. The slanted portion E ₆ is
It represents the cross-sectional area of passage between the blocking surface 21-3 and the outlet peripheral edge 26-1. That is, the passing cross-sectional area between the blocking surface 21-3 and the outlet peripheral edge 26-1 at this time is equal to or smaller than the passing cross-sectional area S ₁ between the straight peripheral surface 20-3 and the outlet peripheral edge 26-1.

The change in the passage cross-sectional area due to the two tapered peripheral surfaces 20-1 and 20-2 causes the rate of change of the passage cross-sectional area to become slow when the discharge volume is small. The throttling action due to the slow change of the passage cross-sectional area gradually reduces the amount of refrigerant gas flowing from the suction passage 26 into the suction chamber 3-1. Therefore, the suction chamber 3
The amount of refrigerant gas drawn into the cylinder bore 1-1 from -1 also gradually decreases, and the discharge capacity gradually decreases. Therefore, the discharge pressure gradually decreases, and the load torque of the compressor does not fluctuate significantly in a short time. As a result, the fluctuation of the load torque in the clutchless compressor from the maximum discharge capacity to the minimum discharge capacity becomes slow, and the impact due to the fluctuation of the load torque is alleviated.

As shown in FIGS. 4 and 6, when the blocking surface 21-3 of the blocking body 21 contacts the positioning surface 27, the suction passage 2
The cross-sectional area of passage at 6 becomes zero, and the inflow of refrigerant gas from the external refrigerant circuit 35 to the suction chamber 3-1 is blocked. If the refrigerant gas inflow from the external refrigerant circuit 35 to the suction chamber 3-1 is blocked, the refrigerant circulation in the external refrigerant circuit 35 is stopped. When the passage cross-sectional area in the suction passage 26 becomes zero, the inclination angle of the swash plate 15 becomes the minimum. Therefore, the minimum inclination angle of the swash plate 15 is regulated by the contact between the blocking surface 21-3 of the blocking body 21 and the positioning surface 27. That is, the positioning surface 27, the blocking body 21, and the thrust bearing 28 constitute the minimum tilt angle defining means.

The throttle body 20 starts to reduce the passage cross-sectional area in the suction passage 26 from an intermediate inclination angle between the maximum inclination angle and the minimum inclination angle of the swash plate 15, and this passage cross-sectional area decreases as the inclination angle of the swash plate 15 decreases. Decrease. And straight surface 2
When 0-3 starts to enter the suction passage 26, the passage cross-sectional area in the suction passage 26 continues to be constant. The throttle body 20 makes the passage cross-section in the suction passage 26 a constant value S ₁
After continuing the state of being narrowed to, the swash plate 15 reaches the minimum tilt angle.

The minimum tilt angle of the swash plate 15 is slightly larger than 0 °. This minimum tilt angle state is brought about when the blocking body 21 is arranged in the closed position that blocks the communication between the suction passage 26 and the accommodation hole 13. The blocking body 21 is switched and arranged in conjunction with the swash plate 15 between the closed position and the open position separated from this position.

Since the minimum inclination angle of the swash plate 15 is not 0 °,
Discharge from the cylinder bore 1-1 to the discharge chamber 3-2 is performed even in a state where the swash plate tilt angle is minimum. Cylinder bore 1-1
The refrigerant gas discharged from the discharge chamber 3-2 from the pressure supply passage 3
Through 1 into the crank chamber 2-1. Crank chamber 2-1
The refrigerant gas therein flows into the suction chamber 3-1 through the passage 30 and the pressure release passage of the pressure release port 21-4, and the refrigerant gas in the suction chamber 3-1 is sucked into the cylinder bore 1-1. It is discharged to the discharge chamber 3-2. That is, when the swash plate tilt angle is at a minimum, the discharge chamber 3-2, which is the discharge pressure region, the pressure supply passage 31, and the crank chamber 2-.
1, a passage 30, a pressure release port 21-4, a suction chamber 3-1 which is a suction pressure region, and a circulation passage through the cylinder bore 1-1 are formed in the compressor, and a discharge chamber 3-2 and a crank chamber 2 are provided. -1 and the suction chamber 3-1 have a pressure difference. Therefore, the refrigerant gas circulates in the circulation passage, and the lubricating oil flowing with the refrigerant gas lubricates the inside of the compressor.

When the cooling load increases from the state of FIG. 6,
This increase in the cooling load appears as a temperature rise in the evaporator 38, and the detected temperature in the evaporator 38 exceeds the set temperature. The control computer C commands the excitation of the solenoid 33 based on this detected temperature shift. Solenoid 33
The pressure supply passage 31 is closed by the excitation of the crank chamber 2-1.
The pressure is reduced based on the pressure released through the passage 30 and the pressure release port 21-4. Due to this pressure reduction, the blocking surface 21-3 of the blocking body 21 is separated from the positioning surface 27. With this separation, the passage cross-sectional area in the suction passage 26 gradually increases, and the amount of refrigerant gas flowing from the suction passage 26 into the suction chamber 3-1 gradually increases. Therefore, the amount of the refrigerant gas sucked from the suction chamber 3-1 into the cylinder bore 1-1 also gradually increases, and the discharge capacity gradually increases. Therefore, the discharge pressure gradually increases, and the load torque of the compressor does not change significantly in a short time. As a result, the fluctuation of the load torque in the clutchless compressor during the period from the minimum discharge capacity to the maximum discharge capacity becomes slow, and the impact due to the fluctuation of the load torque is alleviated.

The lubricating oil in the compressor flows out to the external refrigerant circuit 35 together with the refrigerant gas flowing out of the compressor, and the lubricating oil flowing out to the external refrigerant circuit 35 flows back into the compressor together with the refrigerant gas. In order to recirculate the lubricating oil flowing out to the external refrigerant circuit 35 into the compressor, the refrigerant flow rate in the external refrigerant circuit 35 needs to be a predetermined amount or more. The refrigerant flow rate depends on the inclination angle of the swash plate 15, and when the inclination angle of the swash plate 15 cannot bring about the predetermined amount of refrigerant flow rate, only the refrigerant gas flows back into the compressor. Since the lubricating oil in the compressor continues to flow out to the external refrigerant circuit 35 together with the refrigerant gas, if the lubricating oil does not flow back from the external refrigerant circuit 35 into the compressor, the inside of the compressor will be insufficiently lubricated. When the refrigerant circulation in the external refrigerant circuit 35 is blocked, the refrigerant gas also does not flow back into the compressor, and the refrigerant gas in the compressor circulates in the compressor, so that the lubricating oil in the compressor flows out of the compressor. There is no end. But,
When the refrigerant flow rate in the state where the refrigerant circulation in the external refrigerant circuit 35 is not blocked has not reached the flow rate required to recirculate the lubricating oil, insufficient lubrication in the compressor occurs.

If the flow rate of the refrigerant gas discharged from the compressor to the external refrigerant circuit 35 is a certain amount or less, the lubricating oil in the compressor will not flow out to the external refrigerant circuit 35 together with the refrigerant gas. Further, when the flow rate of the refrigerant in the external refrigerant circuit 35 becomes a certain amount or less, the lubricating oil does not flow back from the external refrigerant circuit 35 into the compressor, and only the refrigerant gas flows back into the compressor.
When the flow rate of the refrigerant is small, the discharging action causes the lubricating oil to flow more easily than the suction action. Therefore, there is a state in which the lubricating oil in the compressor is made to flow out to the external refrigerant circuit 35, even though the refrigerant flow rate in the external refrigerant circuit 35 is such that the lubricating oil cannot flow back.

In this embodiment, the passage in the suction passage 26
Cross-sectional area is a constant value S₁When squeezed to
The flow rate of the refrigerant discharged to the medium circuit 35 is lubricated from the inside of the compressor.
The constant value S so as not to cause oil spill₁Is set
There is. The cross section of passage is a constant value S ₁Swash plate when starting to squeeze
The inclination state of 15 is a state in which there is no diaphragm action by the diaphragm body 20.
Then, let the lubricating oil in the compressor flow out to the external refrigerant circuit 35.
Provides a refrigerant flow rate. However, the passage cross-section is set to a constant value S₁
When the condition is squeezed to, the lubricating oil in the compressor is sent to the external refrigerant circuit 35.
Provides a flow rate of refrigerant that does not flow out. Therefore, the return of the lubricating oil
Even if there is no flow, the lubricating oil in the compressor will not flow out.
In addition, insufficient lubrication in the compressor does not occur. Also, recirculate the lubricating oil
The minimum tilt angle of the swash plate to the tilt angle corresponding to the refrigerant flow rate
Since it can be made smaller, power consumption is also reduced.

When the vehicle engine is stopped, the operation of the compressor is also stopped and the electromagnetic opening / closing valve 32 is demagnetized. Solenoid open / close valve 32
The declination of the swash plate 15 brings the swash plate 15 to the minimum tilt angle. If the operation of the compressor is stopped, the pressure in the compressor becomes uniform, but the tilt angle of the swash plate 15 is kept at the minimum tilt angle by the spring force of the tilt reducing spring 41. Therefore, when the operation of the compressor is started by starting the vehicle engine, the swash plate 15 starts to rotate from the minimum inclination state in which the load torque is the smallest, and there is almost no shock at the time of starting the compressor.

In this embodiment, the swash plate 15 is provided with a blocking member 21 which can switch between a closed position where the refrigerant gas cannot be introduced and an open position where the refrigerant gas can be introduced from the external refrigerant circuit 35 to the suction chamber 3-1 which is the suction pressure region. Refrigerant circulation is blocked in conjunction with tilting. By adopting such a refrigerant circulation prevention structure, the swash plate 15
The effect of suppressing load torque fluctuations in switching between the maximum inclination angle and the minimum inclination angle of is extremely high. Although the opening and closing of the pressure supply passage 31 is frequently repeated depending on the increase / decrease of the cooling load, there is no ON-OFF shock due to the high torque fluctuation suppressing effect of the refrigerant circulation blocking structure of the present embodiment.

The outlet of the suction passage 26 formed on the extension line of the rotary shaft 9 is blocked by the blocking member 21 which moves along the rotary shaft 9. The pressing force for this blocking causes the inclination angle of the swash plate 15 to change. Obtained from the force that urges in a decreasing direction.
Such a blocking arrangement ensures a seal between the positioning surface 27 and the blocking surface 21-3 of the blocking body 21.

In this embodiment, the size relationship between the diameter of the straight peripheral surface 20-3 and the diameter of the suction passage 26 influences the proper setting of the cross-sectional area of passage in the suction passage 26. Is easy. Further, the diaphragm body 20 is the blocking body 2.
The suction passage 26 is integrally formed at the center of the radius of No. 1, and the suction passage 26 is on the extension line of the movement path of the throttle body 20. The diameter of the straight peripheral surface 20-3 is smaller than the diameter of the suction passage 26. Therefore, even if the axis of the blocking body 21 and the axis of the suction passage 26 are slightly deviated from each other, the throttle body 20 integrally interlocked with the switching operation of the blocking body 21 smoothly appears in and out of the suction passage 26. Therefore, the passage cross-sectional area in the suction passage 26 is appropriately reduced.

Since the diaphragm body 20 and the blocking body 21 are integrated, the matching between the switching operation of the blocking body 21 and the diaphragm operation of the diaphragm body 20 depends on how the length of the diaphragm body 20 is set. Diaphragm 20
Is easy to set, and the switching operation of the blocking body 21 and the diaphragm operation of the diaphragm body 20 can be easily matched.

Next, the embodiment shown in FIGS. 9 and 10 will be described. Members having the same configurations as those in the first embodiment are designated by the same reference numerals,
The detailed description is omitted. In this embodiment, a capacity control valve 43 is attached to the rear housing 3. The pressure in the crank chamber 2-1 is controlled by the capacity control valve 43. A discharge pressure introducing port 44-1, a suction pressure introducing port 44-2, and a pressure releasing port 44-3 are provided in a valve housing 44 that constitutes the capacity control valve 43. Discharge pressure introduction port 44-1
Communicates with the discharge chamber 3-2 via the passage 45. The suction pressure introducing port 44-2 communicates with the suction passage 26 through the suction pressure introducing passage 46, and the pressure release port 44-3 communicates with the crank chamber 2-1 through the passage 47.

The pressure in the suction pressure detecting chamber 49 communicating with the suction pressure introducing port 44-2 is adjusted by the adjusting spring 5 through the diaphragm 50.
Oppose 1. The spring force of the adjusting spring 51 is the diaphragm 5
It is transmitted to the valve body 53 via 0 and the rod 52. Disc 5
The spring force of the return spring 54 acts on 3. Valve body 53
The spring action direction of the return spring 54 with respect to is the direction to close the valve hole 44-4, and the valve body 53 which receives the spring action of the return spring 54 responds to the fluctuation of the suction pressure in the suction pressure detection chamber 49. Open and close 4.

When the solenoid 33 is excited, the pressure supply passage 3
When 1 is closed, when the suction pressure is high (the cooling load is large), the valve body 53 is closed, and the discharge chamber 3-2 to the passage 4 are closed.
5, the pressure supply passage passing through the capacity control valve 43 and the passage 47 is closed. The refrigerant gas in the crank chamber 2-1 passes through the passage 30,
Since it flows into the suction chamber 3-1 via the pressure release port 21-4, the pressure in the crank chamber 2-1 decreases. Further, since the suction pressure in the cylinder bore 1-1 is also high, the difference between the pressure in the crank chamber 2-1 and the suction pressure in the cylinder bore 1-1 becomes small.
Therefore, the swash plate inclination angle becomes large as shown in FIG.

On the contrary, the suction pressure is low (the cooling load is small).
In this case, the valve opening of the valve element 53 becomes large and the amount of refrigerant gas flowing from the discharge chamber 3-2 into the crank chamber 2-1 becomes large. Therefore, the pressure in the crank chamber 2-1 rises. Further, since the suction pressure in the cylinder bore 1-1 is low, the difference between the pressure in the crank chamber 2-1 and the suction pressure in the cylinder bore 1-1 becomes large. Therefore, the tilt angle of the swash plate becomes small.

When the suction pressure becomes extremely low (no cooling load), the valve opening of the valve element 53 becomes large as shown in FIG. Therefore, the pressure in the crank chamber 2-1 rises, and the swash plate 1
The tilt angle of 5 shifts to the minimum tilt side. Also, the solenoid 33
When is demagnetized, the pressure supply passage 31 opens. Solenoid 33
When is excited, the pressure supply passage 31 is cut off.

That is, in this embodiment, the swash plate tilt angle is continuously variably controlled according to the cooling load. Then, the control computer C controls the demagnetization of the electromagnetic on-off valve 32 based on the ON-OFF signal of the air conditioner operation switch 40.

In this embodiment, the diaphragm peripheral surface 42-0 of the diaphragm body 42 projecting from the blocking body 21 is composed of a tapered peripheral surface 42-1 and a straight peripheral surface 42-3. Tapered peripheral surface 42-1 is swash plate 1
From the state of the intermediate inclination angle of 5, the passing cross-sectional area in the suction passage 26 is reduced, and the straight peripheral surface 42-2 continues the state in which the passing cross-sectional area is narrowed to the constant value S ₁ .

Also in this embodiment, the lubricating oil in the compressor does not flow out even when the lubricating oil is not recirculated, and the insufficient lubrication in the compressor does not occur. Further, since the minimum inclination angle of the swash plate can be reduced to an inclination angle corresponding to the flow rate of the refrigerant that cannot recirculate the lubricating oil, power consumption is also reduced. Next, FIGS.
Example 3 will be described. The members having the same configurations as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. In this embodiment, the blocking body 21 is integrally formed with a cylindrical throttle body 57. The diameter of the outer peripheral surface of the throttle body 57 is made slightly smaller than the diameter of the suction passage 26, and the throttle body 57 always enters the suction passage 26. As shown in FIG.
A slit 57-1 is formed by cutting on the peripheral surface.
The slit 57-1 is widened from the intermediate position of the diaphragm to the tip. When a part of the slit 57-1 protrudes from the suction passage 26 and the inclination angle of the swash plate 15 changes, the passage cross-sectional area in the suction passage 26 gradually changes. When all the slits 57-1 are in the suction passage 26, the passage cross-sectional area of the suction passage 26 is the same as the straight peripheral surface 57-2 of the throttle body 57 on the proximal side and the suction passage 26.
It is the cross-sectional area of the passage between the inner peripheral surface and. This passage cross section has a constant value S ₁ as in the first embodiment. Slit 57-1
Gradually increases or decreases the passage cross-sectional area in the suction passage 26, and the straight peripheral surface 57-2 maintains the state in which the passage cross-sectional area is reduced to a constant value S ₁ . The straight peripheral surface 57-2 is the suction passage 2
In the state where all of them have entered the position 6, the blocking surface 21-3 contacts the positioning surface 27.

Also in this embodiment, the lubricating oil in the compressor does not flow out even when the lubricating oil is not recirculated, and the insufficient lubrication in the compressor does not occur. Further, since the minimum inclination angle of the swash plate can be reduced to an inclination angle corresponding to the flow rate of the refrigerant that cannot recirculate the lubricating oil, power consumption is also reduced. Further, the configuration in which the throttle body 57 is always inserted into the suction passage 26 facilitates the proper setting of the degree of throttling of the passage cross-sectional area in the suction passage 26.

Next, the embodiment shown in FIGS. 14 and 15 will be described. In this embodiment, a variable displacement compressor provided with an electromagnetic clutch 58 for transmitting the driving force of the vehicle engine to the rotary shaft 9 is targeted, but the members having the same configurations as those in the second embodiment are designated by the same reference numerals, and Detailed description is omitted. The electromagnetic clutch 58 receives the excitation / demagnetization control of the control computer C, and the control computer C performs the excitation / demagnetization control of the electromagnetic clutch 58 based on the detected temperature information from the temperature sensor 39 and the ON / OFF signal of the air conditioner operation switch 40. In this embodiment, the tilt angle of the swash plate 15 becomes the minimum tilt angle when the cylindrical positioning body 59 that constitutes the minimum tilt angle defining means comes into contact with the positioning surface 60. A pressure release port 59-1 is formed on the front end surface of the positioning body 59. The pressure release port 59-1 communicates the inside of the cylinder of the positioning body 59 with the inside of the accommodation hole 13. A diaphragm 61 is integrally formed at the tip of the positioning body 59. The peripheral surface of the throttle body 61 is composed of a first tapered peripheral surface 61-1, a second tapered peripheral surface 61-2 and a straight peripheral surface 61-3 as in the first embodiment.

As shown in FIG. 15, even when the positioning body 59 abuts the positioning surface 60, the passage cross-sectional area in the suction passage 26 passes between the straight peripheral surface 61-3 and the inner peripheral surface of the suction passage 26. The cross-sectional area S ₁ is obtained. Also in this embodiment, the lubricating oil in the compressor does not flow out even when the lubricating oil is not recirculated, and the lack of lubrication in the compressor does not occur.
Further, since the minimum inclination angle of the swash plate can be reduced to an inclination angle corresponding to the flow rate of the refrigerant that cannot recirculate the lubricating oil, power consumption is also reduced.

[0066]

As described in detail above, in the inventions of claims 1 and 2, the passage cross-sectional area is reduced before the inclination angle of the swash plate reaches the minimum inclination angle, and then the passage cross-sectional area is made constant. Since the swash plate tilt angle is changed to the minimum tilt angle after the squeezing condition is continued, the swash plate minimum tilt angle is required to prevent the lubricant oil from flowing out while avoiding the lubricant oil flow inside the compressor. The inclination angle can be reduced, and power consumption can be reduced while avoiding insufficient lubrication in the compressor.

According to the third aspect of the present invention, since the suction passage is formed on the extension line of the movement path of the throttle body, it is easy to properly set the degree of throttling of the passage sectional area in the suction passage. In the invention of claim 4, since the diaphragm body and the blocking body are integrated, it is easy to match the switching operation of the blocking body and the diaphragm operation of the diaphragm body.

According to the fifth aspect of the present invention, the throttling action of the throttle body is changed between the throttling action of the tapered peripheral surface and the throttling action of the straight peripheral surface. Avoidance of insufficient lubrication and reduction of power consumption can be achieved.

According to the sixth aspect of the invention, the suction passage is throttled by the first taper peripheral surface, the second taper peripheral surface and the straight peripheral surface, so that the fluctuation in the load torque is slowed and the lubrication in the compressor is performed. Avoidance of shortage and reduction of power consumption can be achieved.

[Brief description of drawings]

FIG. 1 is a side sectional view of an entire compressor of a first embodiment embodying 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 of the entire compressor in which the swash plate tilt angle is at a minimum.

FIG. 5 is an enlarged cross-sectional view of a main part in which the swash plate tilt angle is at a maximum.

FIG. 6 is an enlarged cross-sectional view of a main part in which the swash plate inclination angle is at a minimum.

7 is an enlarged cross-sectional view taken along the line CC of FIG.

FIG. 8 is a graph showing a change in passage cross-sectional area in the suction passage.

FIG. 9 is a side sectional view of the entire compressor showing another example.

FIG. 10 is an enlarged cross-sectional view of a main portion in which the swash plate tilt angle is at a minimum.

FIG. 11 is an enlarged cross-sectional view of a main part showing another example.

FIG. 12 is an enlarged cross-sectional view of an essential part in which the swash plate tilt angle is at a minimum.

13 is an enlarged cross-sectional view taken along line DD of FIG.

FIG. 14 is a side sectional view of the entire compressor showing another example.

FIG. 15 is an enlarged cross-sectional view of an essential part in which the swash plate tilt angle is in a minimum state.

[Explanation of symbols]

1-1 ... Cylinder bore, 2-1 ... Crank chamber, 3-1 ... Suction chamber serving as suction pressure region, 3-2 ... Discharging chamber serving as discharge pressure region, 1
5 ... swash plate, 20 ... diaphragm body, 20-0 ... diaphragm peripheral surface, 20-1 ...
1st taper peripheral surface, 20-2 ... 2nd taper peripheral surface, 20-3
... Straight peripheral surface, 21 ... Blocking body that constitutes the minimum inclination regulating means, 22 ... Single-headed piston, 26 ... Suction passage, 27 ...
Positioning surface that constitutes the minimum tilt angle defining means, 28 ... Thrust bearing that constitutes the minimum tilt angle defining means, 42 ... Throttle body, 42-0 ... Throttle circumferential surface, 42-1 ... Tapered circumferential surface, 42-2 ...
Straight peripheral surface, 57 ... diaphragm, 57-1 ... slit, 5
7-2 ... Straight peripheral surface, 59 ... Positioning body constituting minimum tilt angle defining means, 61 ... Stopper body, 61-1 ... First tapered peripheral surface, 61-2 ... Second tapered peripheral surface, 61-3 … Straight surface.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Michiyuki 2-chome Toyota-cho, Kariya City, Aichi Prefecture Toyota Industries Corporation Ltd.

Claims (6)

[Claims] Claims: 1. A piston is accommodated in a cylinder bore so as to be capable of reciprocating linear movement, and an inclination angle of the swash plate is controlled according to a difference between a suction pressure and a pressure in a crank chamber accommodating the swash plate to control a discharge pressure. While supplying the pressure of the area to the crank chamber,
In a variable displacement compressor that regulates the pressure in the crank chamber by releasing the pressure in the crank chamber to the suction pressure region via the pressure relief passage, the minimum tilt angle of the swash plate is specified to provide a non-zero discharge capacity. An inclination regulating means and a throttle body for narrowing the passage cross-sectional area in the suction passage for introducing the refrigerant gas from the external refrigerant circuit to the suction pressure region in association with the tilt of the swash plate are provided, and the tilt angle of the swash plate is set to the minimum tilt angle. A variable displacement compressor in which the cross-sectional area of the swash plate is reduced to a minimum, and then the tilt angle of the swash plate is shifted to the minimum tilt angle. 2. A piston is housed in a cylinder bore so as to be capable of reciprocating linear movement, and the inclination angle of the swash plate is controlled according to the difference between the suction pressure and the pressure in the crank chamber housing the swash plate to control the discharge pressure. While supplying the pressure of the area to the crank chamber,
In a clutchless variable displacement compressor that regulates the pressure in the crank chamber by releasing the pressure in the crank chamber to the suction pressure region via the pressure relief passage, the minimum tilt angle of the swash plate is specified to provide a non-zero discharge capacity. Minimum inclination regulating means, a shutoff body that is interlocked with the tilt of the swash plate and is switched between an uninjectable position and an injectable open position of the refrigerant gas from the external refrigerant circuit to the suction pressure region, and an external refrigerant. A throttle body that throttles the passage cross-sectional area in the suction passage for introducing the refrigerant gas from the circuit to the suction pressure region in conjunction with the switching operation of the blocking body, and the passage cutoff before the inclination angle of the swash plate reaches the minimum inclination angle. A variable displacement compressor in which the area is reduced and then the passing cross-sectional area is continuously reduced and then the tilt angle of the swash plate is shifted to the minimum tilt angle. 3. The suction passage is formed on an extension line of the movement path of the throttle body.
The variable capacity compressor according to the item. 4. The variable displacement compressor according to claim 3, wherein a throttle body is a part of the blocking body, and enters the suction passage to reduce a passage cross-sectional area in the suction passage. 5. The suction passage is narrowed by a diaphragm peripheral surface of a diaphragm body, the diaphragm peripheral surface being parallel to the taper peripheral surface inclined with respect to the moving path of the diaphragm body, and Consisting of a straight peripheral surface continuous with the tapered peripheral surface,
5. The variable displacement compressor according to claim 3, wherein the throttling action of the throttle circumferential surface due to the decrease of the swash plate inclination angle shifts from the throttling action of the tapered circumferential surface to the throttling action of the straight circumferential surface. . 6. The taper peripheral surface includes a first taper peripheral surface,
The second taper peripheral surface is continuous with the second taper peripheral surface, and the inclination of the second taper peripheral surface is smaller than the inclination of the first taper peripheral surface. 6. The variable displacement compressor according to claim 5, wherein the first taper peripheral surface drawing operation shifts to a second taper peripheral surface drawing operation.