JPH03143725A - Variable displacement compressor - Google Patents

Abstract

PURPOSE:To make the delivery volume settable to zero by providing an opening- closing valve, which is opened for placing a swash plate in a 0 deg. condition when a compressor is turned off, in a passage through which a delivery port communicates with a casing, in the compressor in which a tilt angle of the swash plate is controlled in accordance with a pressure introduced into the casing. CONSTITUTION:In a variable displacement compressor in which a refrigerant in sucked from a suction port 17, pressurized and delivered from a delivery port 18 by a reciprocating motion of pistons 19 slidably fitted into a cylinder block 12, a tilt angle of a swash plate 24 is decreased by introducing a delivery pressure into a casing 15 and increased by introducing a suction pressure into the casing 15, by a control means 32. Here in a passage 46 through which the delivery port 18 communicates with the casing 15, an opening-closing valve 47, which is opened so as to place a swash plate 27 in a 0 deg. condition when the compressor is turned off, is provided. This opening-closing valve 47 set-holds the swash plate 27 to a predetermined value larger than 0 deg. by an actuator 41 when the compressor is turned on.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a variable capacity compressor suitable for use in a vehicle air conditioner.

B. Prior art FIG. 3 is a sectional view schematically showing a variable capacity compressor of this type disclosed in, for example, Japanese Patent Application Laid-Open No. 58-158382. This is a variable discharge rate swash plate type compressor, which allows the operating stroke h of the piston relative to the cylinder and, in turn, the discharge capacity (discharge flow rate per revolution) of the refrigerant to be compressed to be changed and adjusted.

In FIG. 3, the variable discharge rate swash plate compressor is provided with a plurality of cylinders 13 (here, only one is shown to avoid complexity) occupying equiangularly spaced positions in the circumferential direction and parallel to the axial direction. a cylinder block 12 and an inner casing chamber 1 covering one end surface of the cylinder block 12;
The compressor main body 11 includes a casing 14 forming a cylinder block 5 and a cylinder head 16, which is attached to the other end surface of the cylinder block 12 and has a suction port 17 and a discharge port 18 corresponding to each cylinder 13, respectively. ing.

Each cylinder 13 of the cylinder block 12 is fitted with a piston 19 capable of sliding stroke in the axial direction, and as described later, as the piston 19 strokes,
A low-temperature, low-pressure gaseous refrigerant is sucked in from the suction port 17 via a suction valve, compressed under pressure, and discharged to the discharge port 18 as a high-temperature, high-pressure gaseous refrigerant. A rotating shaft 20, which is pivotally supported between the center portions of the cylinder block 12 and the casing 14, is rotationally driven by an engine (not shown) outside the casing 14 via an electromagnetic clutch 21 and a pulley 22.

Further, a rotary drive plate 24 is pivotally supported on the rotating shaft 20, and the relative inclination angle with respect to the axial direction can be changed in accordance with the range from the minimum discharge amount to the maximum discharge amount. The minimum inclination angle, that is, the minimum discharge amount of the rotary drive plate 24 is regulated by a leaf spring 26 attached to the rotating shaft 20.
A non-rotary wobble plate 27 is supported on the cylinder side end surface of 4 via a thrust bearing.

The lower fork end of the non-rotary wobble plate 27 is mounted on a sliding piece 2 on a guide shaft 29 mounted in the casing chamber 15.
8 and are slidably engaged.

Only its rotational operation is restricted. The end surface of this non-rotary wobble plate 27 and the piston 19 in each cylinder 13
are connected by a piston rod 30, so that the operating stroke of the piston 19, that is, the compressor discharge capacity, can be changed from a minimum value to a maximum value in response to changes in the inclination angle of the rotary drive plate 24. . Incidentally, reference numeral 31 denotes lubricating oil stored in the lower part of the casing chamber 15 in order to smoothly tilt the non-rotary wobble @27 on the guide shaft 29.

In the configuration of this conventional example, the rotary drive plate 24
is rotationally driven by the rotary shaft 20, the non-rotary wobble plate 27, whose rotation is restrained, rotates the inside of each cylinder 13 with an operating stroke corresponding to the inclination angle given to the rotary drive plate 24 at that time. The piston 19 is reciprocated, and the suction port 17 sucks in the refrigerant, compresses it under pressure, and discharges it from the discharge port 18.

Here, the inclination angle, that is, the non-rotary wobble plate 2
The operation stroke of the piston 19 reciprocally operated by the piston 7 is controlled by selectively introducing suction pressure Ps or discharge pressure Pd into the casing chamber 15 by the control valve device 32 provided in the cylinder head 16, and Pressure difference, in other words, piston chamber and casing chamber 1
Control is performed by automatically adjusting the inclination angle of the rotary drive plate 24 in accordance with the set pressure using the pressure difference between the rotary drive plate 24 and the inside of the rotary drive plate 24. When adjusting the discharge amount, the leaf spring 26 serving as a minimum discharge amount stopper regulates the inclination angle of the non-rotary wobble plate 27 so that it does not become less than the minimum discharge amount.

In other words, in the differential pressure type inclination angle control, the inclination angle of the non-rotary wobble plate 27 is kept below the minimum value, e.g.
If the tilt angle is set to zero, the tilt angle cannot be returned from the zero position, so the leaf spring 26 regulates the minimum tilt angle to a predetermined value greater than 0 degrees.

The control valve device 32 controls the suction pressure Ps to the casing chamber 1.
A suction side valve 33 for introducing the discharge pressure Pd into the casing chamber 15, a discharge side valve 34 for introducing the discharge pressure Pd into the casing chamber 15, and a pressure-responsive bellows for switching and controlling both these valves 33 and 34 according to a set pressure. and a control section 35.

When the suction pressure Ps in the compressor exceeds the set pressure,
As shown in FIG. 4(a), the control unit 35 responds by closing the discharge side valve 34, opening the suction side valve 33, and introducing suction pressure Ps into the casing chamber 15 from the suction pressure passage 36. The inclination angle of the rotary drive plate 24 is increased to increase the discharge amount. Furthermore, when the suction pressure Ps becomes lower than the set pressure, as shown in FIG. Room 1
5, the inclination angle of the rotary drive plate 24 is made small to reduce the discharge amount, and this operation is repeated to maintain the discharge pressure Pdtrl constant at all times.

C6 Problems to be Solved by the Invention In the configuration of such a conventional variable discharge rate swash plate compressor, the discharge capacity is controlled by the pressure difference between the piston chamber and the casing chamber 15, and the inclination angle of the non-rotary wobble plate 27 is controlled by the pressure difference between the piston chamber and the casing chamber 15. is regulated to a predetermined value greater than 0 degrees by a leaf spring 26 so that it does not become less than the minimum discharge amount. Therefore, for example, when the cooling effect inside the vehicle becomes sufficient and the inclination angle of the non-rotary wobble plate 27 needs to be set to below the minimum value corresponding to the minimum discharge amount or below, or to zero, the rotating shaft 2 There is no countermeasure other than stopping the rotational drive of the rotary drive plate 24 itself, and for this reason, an electromagnetic clutch 21 is essential between the rotating shaft 20 and the engine rotating shaft to connect and disconnect them.

However, in this way, the non-rotary wobble plate 27
The reason why the electromagnetic clutch 21 transmits or cuts off the driving force to the rotating shaft 20, and in turn, frequently repeats the operation or stopping of the device itself, is due to engine load fluctuations, in order to make the inclination angle of the rotary shaft 20 less than the minimum value or zero. This is not desirable as it will be repeated frequently. Furthermore, regarding the attachment of the electromagnetic clutch 21, which is relatively expensive and has a considerable weight, it was necessary to consider an alternative means from the viewpoint of reducing the cost and weight as well as downsizing the electromagnetic clutch 21.

A technical object of the present invention is to reduce the discharge capacity to zero without interrupting the rotation of the compressor.

00 Means for Solving the Problems The present invention will be explained in conjunction with FIG. 1 illustrating an embodiment of the present invention. A piston 19 and a casing 15 that discharge the air from the discharge port 18.
The piston 19 rotates integrally with the rotating shaft 20 within the
and a swash plate 24 whose inclination angle is adjustable to make the stroke amount variable.

control means 3 for adjusting the inclination angle of the swash plate 27 by selectively guiding discharge pressure or suction pressure into the casing 15;
2, and is applied to a variable displacement compressor in which the angle of inclination of the swash plate 27 decreases when discharge pressure is introduced into the casing 15, and increases when the suction pressure is introduced.

The above technical problem is achieved with the following configuration.

The swash plate 27 has an inclination angle that can be set to 0 degrees, and a passage 46 that communicates the discharge port 18 with the casing 15 chamber.
This passage 46 is opened and closed, and the swash plate 27 is opened and closed when the compressor is turned off.
The on-off valve 47 is opened to bring the compressor to the 0 degree state, and the swash plate 27 is pushed from the 0 degree state in response to the compressor being turned on.
Actuator 41 that is set and held at a predetermined value greater than
and.

81 action When the compressor is off, the on-off valve 47 is opened and discharge pressure is introduced into the casing 15 from the discharge port 18,
The angle of inclination of the swash plate 27 becomes zero, and the discharge capacity of the compressor becomes zero. When the compressor is turned on in this state, the swash plate 27 is driven by the actuator 41, and its inclination angle becomes a value larger than zero. Therefore, when suction pressure is introduced into the casing 15 by the control means 32, the inclination angle of the swash plate 27 easily increases due to the pressure difference between the front and rear sides of the piston 19.

In the above-mentioned sections and section E, which describe the present invention in detail, figures of embodiments are used to make the present invention easier to understand, but the present invention is not limited to the embodiments.

F. Embodiment FIG. 1 is a cross-sectional explanatory diagram showing an embodiment of the variable discharge rate swash plate compressor according to the present invention. The same reference numerals are used to mainly explain the differences.

The stroke amount of the piston 19, that is, the discharge capacity of the compressor, is determined by the non-rotary wobble plate 27 as in the conventional example.
is adjusted by the inclination angle. The angle of inclination becomes larger when the suction pressure Ps is introduced into the gauging chamber 15, and the inclination angle becomes larger when the suction pressure Ps is introduced into the gauging chamber 15.
d becomes smaller, and the minimum inclination angle is set to 0 degrees.

As explained in the prior art section, in a conventional compressor, when the non-rotary wobble plate 27 is set to 0 degrees, the inclination angle is then increased to increase the suction pressure P in the casing chamber 15.
Even if s is guided, no force is applied to the non-rotary wobble plate 27 to increase the angle of inclination, so it does not tilt. Therefore, in this embodiment, a hydraulic actuator 41 is provided integrally with the rotating shaft 20 so as to face the non-rotary wobble plate 27, and when increasing the tilt angle from zero, the assist plunger 41a is used to move the non-rotary wobble plate 27. 2
7 to give the initial inclination angle.

Therefore, a gear pump 42 driven by the rotating shaft 20 is disposed at the axial center of the cylinder block 12. The cylinder block 12 is provided with a suction passage 43 through which oil 31 stored at the bottom of the casing chamber 15 is sucked up by a gear pump 42, and an electromagnetic on-off valve 44 that opens and closes the suction passage 43. Further, a discharge port of the gear pump 42 is communicated with the hydraulic actuator 41 via a passage 45 carefully provided in the rotating shaft 2o. Further, the cylinder head 16 and the cylinder block 12 are provided with a passage 46 for guiding the discharge port 18 into the casing chamber 15, and the cylinder block 12 is provided with an electromagnetic on-off valve 47 for opening and closing the passage 46.

As shown in FIG. 2, the solenoid 44 of the electromagnetic on-off valve 44
S is connected to the normally closed contact 48SO of the relay 48, and the solenoid 47S of the electromagnetic on-off valve 47 is connected to the normally closed contact 4 of the relay 48.
The coil 48C of the relay 48 is connected to a fan switch 51 (not shown) that turns on and off a proa fan, and an air conditioner switch that is connected in series to this switch 51 and turns on and off a compressor. 52, and both ends of these series circuits are connected to the battery 5o and ground, respectively.

The operation of the variable capacity compressor configured in this way will be explained.

When fan switch 51 or air conditioner switch 52 is open, relay 48 is inactive and normally closed contact 488C is closed. Therefore, the solenoid 47 of the on-off valve 47
S is energized via the relay 48 to open the on-off valve 47, thereby communicating the discharge port 18 and the casing chamber 15 via the passage 46, and introducing the discharge pressure Pd into the casing chamber 15. Therefore, the inclination angle of the non-rotary wobble plate 27 becomes 0 degrees, and the discharge capacity of the compressor becomes zero, so that the compressor does not discharge refrigerant despite the rotation of the rotating shaft 20).

Next, when both the proa fan 51 and the air conditioner switch 52 are closed, the relay 48 is activated.

Normally closed contact 48SC opens and normally closed contact 48SO closes.

As a result, the on-off valve 47 closes and the communication between the casing chamber 15 and the discharge port 18 via the passage 46 is cut off, and the on-off valve 44 opens and the gear pump 42
3, the lubricating oil 31 is sucked in, and hydraulic pressure is discharged to the discharge passage 45, thereby extending the assist plunger 41a of the hydraulic actuator 41. The assist plunger 41a pushes the non-rotary wobble plate 27.
The inclination angle is a value that determines the minimum discharge volume that is greater than 0 degrees.

In this state, the suction pressure Ps is
4 in the casing chamber 15, the inclination angle of the non-rotary wobble plate 27 increases due to the pressure difference acting before and after the piston 19, as in the conventional case, and the discharge capacity of the compressor increases. Then, the discharge pressure Pd is
If it is guided by , the angle of inclination will become smaller. On the other hand, when the inclination angle of the non-rotary wobble plate 27 is the minimum capacity value of the assist plunger 41a, the control valve device 32
Even if the discharge pressure Pd is guided to the casing chamber 15 via the assist plunger 41, the assist plunger 41 prevents the inclination angle from becoming lower than that.

As described above, according to this embodiment, even if the inclination angle of the non-rotary wobble plate 27 is set to zero so that the discharge capacity of the compressor becomes zero when the compressor function is stopped, the assist plunger 41a is The non-rotary wobble plate 27 is pushed and forcibly tilted to the minimum inclination angle corresponding to the minimum capacity. therefore,
Restarting is easy, and the electromagnetic clutch that was previously essential is no longer necessary.

Note that the hydraulic actuator for tilting the non-rotary wobble plate 27 having a zero inclination angle to the minimum inclination angle is not limited to this embodiment, and may be an actuator other than a hydraulic type.

G1 Effects of the Invention According to the present invention, the discharge capacity of the compressor can be set to zero, so the electromagnetic clutch, which has been indispensable in the past, can be abolished, making it possible to reduce weight and cost. In addition, compared to the load fluctuation caused by turning on and off the electromagnetic clutch, the load fluctuation between the compressor load when the compressor discharge capacity is at its minimum capacity and the compressor load when the discharge capacity is zero is small, and the The impact can be reduced, and noise and fuel consumption can also be reduced.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional explanatory diagram showing a schematic configuration of a variable displacement compressor to which an embodiment of the present invention is applied, FIG. 2 is an electric circuit diagram thereof, and FIG. 3 is a schematic diagram of a conventional variable displacement swash plate compressor. Cross-sectional view showing the configuration, FIGS. 4(a) and (b)
) is a cross-sectional explanatory view schematically showing modes of each switching operation of the control valve device. 11: Compressor body 12 Niji cylinder block 13
Niji cylinder 14: Casing 15: Casing chamber 16: Cylinder head 17: Suction port
18: Discharge port 19: Piston 20:
Rotating shaft 24: Rotary drive plate 27: Non-rotary wobble plate 31: Lubricating oil 32: Control valve device 36:
Suction pressure passage 37: Discharge pressure passage 41: Hydraulic actuator 41a near assist plunger 42: Gear pump 43, 45: Oil passage 44. 47: Electromagnetic on-off valve 46: Discharge pressure passage 48: Relay 51: Fan switch 52: Air conditioner switch No. Figure 1

Claims (1)

[Claims] A piston that reciprocates within a cylinder block to suck in refrigerant from a suction port, compress it under pressure, and discharge it from a discharge port; It has a swash plate whose inclination angle can be adjusted to be variable, and a control means for adjusting the inclination angle of the swash plate by selectively guiding discharge pressure or suction pressure into the casing. In a variable capacity compressor, the inclination angle of the swash plate becomes smaller when the suction pressure is guided inside, and the inclination angle becomes larger when the suction pressure is introduced, wherein the inclination angle of the swash plate can be set to 0 degrees; a passage communicating between the discharge port and the casing chamber; an on-off valve that opens and closes this passage to bring the swash plate into the 0-degree state when the compressor is turned off; A variable displacement compressor, comprising: an actuator that is pushed from a position to set and maintain a predetermined value greater than 0 degrees.