JP3182944B2 - Oscillating swash plate 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 relates to a swash plate type variable displacement compressor used in, for example, a vehicle air conditioner.

[0002]

2. Description of the Related Art As a conventional minimum displacement start type variable displacement compressor, for example, one disclosed in Japanese Patent Application Laid-Open No. 60-259777 has been proposed. In this compressor,
A cylinder block in which a plurality of cylinder bores for accommodating a single-headed piston are formed in a housing is provided in parallel with each other, a crank chamber is provided in one of the housings to support a rotating shaft, and a lug plate is fitted to the rotating shaft. Fixed,
A swinging swash plate is mounted on the lug plate via a hinge mechanism so as to be able to swing back and forth in the front-rear direction. Then, the rotation swash plate is moved back and forth by the rotation of the rotation shaft to reciprocate the single-headed piston in the cylinder bore, and the refrigerant gas sucked from the suction chamber is compressed in the cylinder bore and discharged to the discharge chamber. Has become. In addition, the reciprocating stroke of the piston is changed by adjusting the differential pressure between the crank chamber pressure acting on the rear surface of the piston and the suction pressure acting on the front surface, thereby changing the reciprocating stroke of the piston and adjusting the discharge capacity. It has become. The swinging swash plate is always urged to a minimum capacity state by a return spring. Further, a suction hole and a discharge hole are formed in the valve plate, and the suction hole is opened and closed by a flapper-shaped suction valve formed in a suction valve forming plate joined to the piston side of the valve plate, and is opposite to the piston of the valve plate. The discharge hole is opened and closed by a discharge valve provided on a discharge valve forming plate joined to the side.

[0003]

When the compressor is started to rotate at a high speed by switching on the air conditioner with the minimum capacity stopped, a large amount of refrigerant gas is sucked from the suction hole by the reciprocating operation of the piston. The pressure in the inner working chamber increases, so that the pressure difference between the pressure in the crank chamber acting on the back of the piston and the suction pressure acting on the front of the piston decreases. Therefore, the bending moment acting in the direction of increasing the inclination angle of the swing swash plate via the piston and the rod increases, and the minimum capacity state cannot be maintained, and it is necessary to maintain the minimum capacity state for high-speed rotation. Nevertheless, there is a problem in that the capacity is increased and power loss is caused, and the starting shock is increased.

For this reason, conventionally, a control valve is provided in an air supply passage communicating the discharge chamber and the crank chamber, and when the rotational speed of the compressor is increased to a predetermined value or more by detecting the rotational speed of the compressor, the control is performed. By opening the valve, high-pressure refrigerant gas is supplied from the discharge chamber to the crank chamber to increase the differential pressure acting on the rear and front surfaces of the piston. Then, the inclination angle of the swinging swash plate is reduced, and the stroke of the piston is reduced to keep the discharge capacity at a minimum. The use of the rotation sensor and the control device as described above has a problem that the device becomes complicated and expensive.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and to reliably perform small-capacity operation when started at a high speed without using a special device, to suppress power loss and to reduce a start shock. It is an object of the present invention to provide an oscillating swash plate type variable displacement compressor that can perform the above operation.

[0006]

In order to achieve the above object, the present invention provides a cylinder block in which a plurality of cylinder bores for accommodating a one-sided piston are formed in a housing in parallel with each other, and a crank chamber is provided in one of the housings. Is provided to support the rotating shaft, a lug plate is fitted and fixed to the rotating shaft, and a swinging swash plate is mounted on the lug plate via a hinge mechanism so as to be able to swing back and forth in the front-rear direction, The swinging swash plate is moved back and forth by the rotation of the rotation shaft to reciprocate the one-side piston in the cylinder bore, and the refrigerant gas sucked from the suction chamber is compressed in the cylinder bore and discharged to the discharge chamber, Further, the inclination angle of the swash plate is changed by adjusting the pressure difference between the crank chamber pressure acting on the rear surface of the piston and the suction pressure acting on the front surface of the piston, thereby reciprocating the straw. In the minimum displacement start type variable displacement compressor in which the swash plate is always urged to the minimum displacement state by a return spring, the suction chamber and the working chamber in the cylinder bore are adjusted. The outlet of the communicating suction passage is opened on the inner peripheral surface of the cylinder bore,
The front surface of the piston at the bottom dead center position in the minimum capacity state is set so as to partially close the outlet of the suction passage.

[0007]

According to the present invention, when the tilt angle of the swash plate is minimum and stopped at the minimum capacity position, when the electromagnetic clutch of the compressor is turned on by switching on the cooling device during low or medium speed running of the vehicle, The rotating shaft is rotated at a low or medium speed, and the swinging swash plate is swung in the front-rear direction via the lug plate and the hinge mechanism. Therefore, the piston is reciprocated with the minimum stroke, and the refrigerant gas sucked from the suction chamber into the working chamber in the cylinder bore through the suction passage is compressed and discharged to the discharge chamber through the discharge hole. Although the suction passage is partially closed even when the piston is at the bottom dead center, since the reciprocating movement of the piston is at low or medium speed, there is almost no throttle function, and the suction of the refrigerant gas is performed properly. Therefore, when the cooling load is large and the suction pressure of the refrigerant gas is high, the differential pressure between the crank chamber pressure acting on the back and the front of the piston and the suction pressure is small, so that the inclination angle of the swinging swash plate increases. Shift to large capacity operation.

When the compressor is stopped and the electromagnetic clutch of the compressor is turned on by switching on the cooling device during high-speed running of the vehicle, the compressor is started at a high speed. At this time, the piston is reciprocated at high speed in the cylinder bore, and when the piston moves to the bottom dead center, the outlet of the suction passage is in an intermediate opening state, so that the amount of refrigerant gas sucked from the suction chamber into the working chamber is reduced. This is suppressed by the action, and the suction pressure in the working chamber decreases. For this reason, the differential pressure between the crank chamber pressure acting on the back of the piston and the suction pressure acting on the front is maintained in a large state, the tilt angle of the swinging swash plate is maintained at a minimum, and the minimum capacity state is reliably maintained. Is done. Then, when the compressor is rotated at a medium speed or a low speed, the suction pressure increases as described above, so that the inclination angle of the swash plate increases, and the operation shifts to a large capacity operation.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 2, a front housing 2 is joined and fixed to a front end surface of the cylinder block 1. A rear housing 3 that partitions and forms a suction chamber 3a and a discharge chamber 3b is joined and fixed to a rear end surface of the cylinder block 1. The cylinder block 1 has a plurality of cylinder bores 1a.

A rotating shaft 4 is rotatably supported via a bearing in a crank chamber 2a formed in the front housing 2. A lug plate 5 is fitted and fixed to the rotary shaft 4, and a rotary swash plate 6 as a swinging swash plate has a hinge mechanism in a long hole 5b formed in a support arm 5a constituting a hinge mechanism of the plate 5. The connecting pins 7 are connected so as to be tiltable in the front-rear direction. Similarly, a slider 8 is supported on the rotating shaft 4 so as to be able to reciprocate in the front-rear direction. A boss 6 a of a rotary swash plate 6 is rotatably connected to the slider 8 by a connecting pin 9. A swing plate 10 is fitted to the outer peripheral surface of the boss portion of the rotary swash plate 6 so as to be relatively rotatable. The slider 8 is urged by a coiled spring 11 in a direction to decrease the inclination angle of the swing plate 10. The swing plate 10 is prevented from rotating by a rotation preventing rod 12 fixed to the cylinder block 1 and the front housing 2. The rotating shaft 4 has the slider 8.
Position of one end of the rocking plate 10 in the minimum capacity state.
The stopper 4a for holding the inclination angle of the constant is fixedly fitted.

A piston 13 is fitted in the cylinder bore 1a. The piston 13 is connected to the rocking plate 10 via a rod 14. A valve plate 15 having a revenue hole 15a and a discharge hole 15b is interposed between the cylinder block 1 and the rear housing 3. At the front of the valve plate 15, the suction hole 15 is provided.
a suction valve plate 16 formed with a flapper-like suction valve 16a for opening and closing the discharge port 15a.
The discharge valve plate 17 on which the discharge valve 17a for opening and closing b is formed is joined to each other. Further, a retainer 18 for regulating the open position of the discharge valve 17a is provided on the rear surface of the discharge valve plate 17.
The retainer plate 18 having a is joined.

The suction hole 15a communicates with a suction passage 1b formed in the cylinder block 1. The circular outlet 1c side of the suction passage 1b is opened to the inner peripheral surface of the cylinder bore 1a. In a state where the inclination angle of the swinging plate 10 is minimum by the spring 11 and the discharge capacity is minimum, when the piston 13 is at the bottom dead center as shown in FIG. Is closed by the outer peripheral surface of the cover.

Further, the rear housing 3 is provided with a capacity control valve (not shown). The capacity control valve opens and closes a bleed passage communicating from the crank chamber 2a to the suction chamber 3a. Then, by adjusting the pressure difference Δp between the crank chamber pressure Pc acting before and after the piston 13 and the suction pressure Ps, the inclination angle of the swing plate 10 is changed, and the piston 13
By changing the stroke, the discharge capacity is adjusted.

Next, the operation of the minimum displacement start type variable displacement compressor configured as described above will be described. In a state where the compressor is stopped, in FIG. 2, the swinging plate 10 is moved backward together with the slider 8 and the rotating swash plate 6 by the spring 11 so that the tilting angle of the swinging plate 10 is minimum and the minimum capacity operation is possible. Become. In this state, when the electromagnetic clutch (not shown) is turned on by switching on the vehicle cooling device, the rotating shaft 4
Is rotated by the power of the engine.

The rotation of the rotary shaft 4 rotates the rotary swash plate 6 and the swing plate 10 via the lug plate 5, the support arm 5a, and the connecting pin 7 in a minimum tilt state. As a result, the piston 13 is reciprocated with the minimum stroke in the cylinder bore 1a, and the refrigerant gas sucked from the suction chamber 3a into the working chamber R in the cylinder bore 1a is compressed, and then is discharged.
5b is discharged to the discharge chamber 3b.

When the electromagnetic clutch of the compressor is turned on when the cooling device is turned on while the vehicle is running at low or medium speed, the rotating shaft 4 is rotated at low or medium speed. At this time, the suction passage 1b is partially closed by the outer peripheral surface of the piston 13 even when the piston 13 is at the bottom dead center. However, the suction of the refrigerant gas is performed properly, and the working chamber R as shown by the solid line in FIG. The pressure (negative pressure) drop in the inside becomes small. Therefore, when the cooling load is large and the suction pressure Ps of the refrigerant gas is high, the pressure difference Δp between the suction pressure Ps and the crank chamber pressure Pc acting on the rear and front surfaces of the piston 13 is small. The angle is increased and the operation is shifted to the large capacity operation.

When the rotary shaft 4 is rotated at a high speed during acceleration of the vehicle, the piston 13 is reciprocated at a high speed in the cylinder bore 1a. For this reason, the suction hole 15a and the suction passage 1b
Refrigerant gas is sucked into the working chamber R in the cylinder bore through the passage, but about one half of the suction passage 1b is closed by the outer peripheral surface of the piston 13 at the bottom dead center. Is suppressed. For this reason, when the engine is started at a high speed, the pressure in the working chamber R decreases as shown by the broken line in FIG. 3, and the difference between the crank chamber pressure Pc acting on the back of the piston 13 and the suction pressure Ps acting on the front is obtained. Pressure Δp
Therefore, the swing plate 10 is biased and held at the minimum capacity state where the inclination angle is the minimum.

When the speed of the vehicle becomes normal and the engine speed becomes steady and the reciprocating speed of the piston 13 decreases, the suction pressure Ps in the working chamber R increases. Is decreased, the inclination angle of the rocking plate 10 is increased, and the operation shifts to large-capacity operation.

When the large-capacity operation of the compressor is continued, the cooling load decreases, and the suction pressure Ps decreases, the pressure difference Δp between the crank chamber pressure Pc and the suction pressure Ps increases, and the swing plate 10 The inclination angle decreases, the stroke of the piston 13 decreases, and a small capacity state is set.

Next, a second embodiment of the present invention will be described with reference to FIGS. In this embodiment, in the above-described compressor, the valve housing chamber 2 is formed by the center hole 1d of the cylinder block 1 and the center hole 3c of the rear housing 3.
A rotary valve 21 is rotatably housed in the housing chamber 20 by a coupling 22 connected to the rotating shaft 4. The rotary valve 21 has a suction passage 23 and a suction guide groove 24 formed therein.
And the suction passage 1b can communicate with each other.

Therefore, when the rotary shaft 4 is rotated, the suction guide groove 24 of the rotary valve 21 communicates with the working chamber R during the suction stroke in FIG. 5, and the refrigerant gas is drawn into the working chamber R from the suction chamber 3a. Is done. In the compression stroke, the gas is compressed in the working chamber R with the suction passage 1b closed by the outer peripheral surface of the rotary valve 21, and the compressed gas is discharged from the discharge hole 15b to the discharge chamber 3b.

Also in the second embodiment, since the outlet 1c of the suction passage 1b is half-opened by the piston 13 in the minimum capacity state, the rocking plate 10 has the minimum inclination angle at the time of high-speed rotation start as in the first embodiment. , The power loss is suppressed, and the shock at the time of starting is reduced.

The present invention is not limited to the above embodiment, but can be embodied as follows. The outlet 1c of the suction passage 1b has an arbitrary shape such as a long hole or an ellipse.

[0024]

As described above in detail, the present invention can reliably perform small-capacity operation when the compressor is started at a high speed without using a special expensive device such as a rotation sensor, thereby reducing power loss. This has the effect of suppressing the starting shock and alleviating the starting shock.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part showing a first embodiment of the invention.

FIG. 2 is a longitudinal sectional view of a wobble plate type variable displacement compressor.

FIG. 3 is a graph showing a relationship between a rotation angle of a rotation shaft and a pressure of a working chamber.

FIG. 4 is a longitudinal sectional view of a wobble plate type variable displacement compressor according to a second embodiment of the present invention.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6 is a perspective view of a rotary valve.

[Explanation of symbols]

Reference Signs List 1 cylinder block, 1a cylinder bore, 1b suction passage, 1c outlet, 2 front housing, 2a
Crank chamber, 3 rear housing, 3a suction chamber, 3b
Discharge chamber, 4 rotating shafts, 5 lug plates, 5a Support arm forming a hinge mechanism, 6 rotating swash plate as a swinging swash plate, connecting pin forming a hinge mechanism, 8 slider, 10 swinging plate, 11 return spring , 13 one-sided piston.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Takenaka 2-1-1 Toyota-cho, Kariya-shi, Aichi Prefecture Inside Toyota Industries Corporation (58) Field surveyed (Int. Cl. ⁷ , DB name) F04B 27 / 08 F04B 27/14

Claims (1)

(57) [Claims] 1. A cylinder block in which a plurality of cylinder bores for accommodating a one-sided piston are housed in a housing, and a cylinder chamber is provided in one of the housings to support a rotating shaft. A lug plate is fitted and fixed, and a swing swash plate is attached to the lug plate via a hinge mechanism so as to be capable of reciprocating swing in the front-rear direction, and the swing swash plate is moved back and forth by rotation of the rotation shaft. Then, the one-sided piston is reciprocated in the cylinder bore, so that the refrigerant gas sucked from the suction chamber is compressed in the cylinder bore and discharged to the discharge chamber. The reciprocating stroke of the piston is changed by changing the inclination angle of the swing swash plate by adjusting the differential pressure with the acting suction pressure, so that the discharge capacity is adjusted. In a minimum displacement start type variable displacement compressor in which a swash plate is always biased to a minimum displacement state by a return spring, an outlet of a suction passage communicating the suction chamber and the working chamber in the cylinder bore is opened to the inner peripheral surface of the cylinder bore, An oscillating swash plate type variable displacement compressor in which a front surface of a piston at a bottom dead center position in a minimum displacement state is set so as to partially close an outlet of the suction passage.