JP2600723B2 - Compressor clutch - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clutch for a compressor, for example, in an air conditioner for an automobile, which is effectively used for transmitting rotational force from an engine for driving an automobile to a refrigerant compressor. It is something.

[Conventional technology and its problems]

2. Description of the Related Art In an automotive air conditioner, an electromagnetic clutch has conventionally been used as a device for transmitting a rotational force from an engine to a compressor. However, when this electromagnetic clutch is used, the drive torque transmitted to the compressor changes suddenly when the clutch is switched on and off, and there is a case where a shock at the time of coupling of the clutch and noise accompanying it are generated.

On the other hand, various measures have been taken to suppress the suction force of the clutch engagement procedure (for example, see Japanese Patent Application Laid-Open No. 60-13 / 1985).
In any case, when an electromagnetic clutch is used, its configuration becomes complicated, and it is difficult to obtain an effect over a wide range with respect to engine-side rotational fluctuations.

To cope with the above problem, a friction clutch having a clutch plate may be used instead of the electromagnetic clutch. However, in such a case, securing a power source required for driving the clutch plate becomes a problem. In other words, when hydraulic pressure or the like is used for driving the clutch plate, a dedicated hydraulic pump for that purpose is required, which complicates the circuit and inevitably increases the size of the entire clutch.

The present invention has been devised in view of the above point, and an object of the present invention is to make it possible to reduce an impact at the time of clutch connection in a clutch that interrupts transmission of power to a compressor. Moreover, it is an object of the present invention to enable such a clutch to be driven without requiring a special external power source.

[Means for solving the problem]

Therefore, the present invention provides a pulley that is rotatably held on a housing and rotates by receiving power from the outside, a drive-side clutch plate that rotates with the pulley, a compressor drive shaft that is disposed to face the drive-side clutch plate, and A driven clutch plate that rotates integrally with the driven clutch plate, and a piston that is arranged to face the driven clutch plate or the driven clutch plate and that changes the contact force between the driven clutch plate and the driven clutch plate according to the axial displacement thereof. A driving means for driving the piston in a direction to increase the contact between the driving side clutch plate and the driven side clutch plate; a pressure chamber provided on a surface of the piston opposed to the driven side clutch plate; A control valve for controlling the communication between the pressure side and the pressure chamber, and a spring for biasing the piston in a direction to reduce the contact between the drive side clutch plate and the driven side clutch plate. To adopt a clutch for a compressor.

[Action]

When the compressor is driven by employing the present invention, first, the piston is moved by the driving means, so that the driving clutch plate and the driven clutch plate are brought into contact with each other to drive the compressor. Thereafter, the discharge pressure obtained by driving the compressor is introduced into the pressure chamber through the control valve, and the drive side clutch plate and the driven side clutch plate are further firmly brought into contact with each other through the piston. Increase pressure further.

〔The invention's effect〕

By adopting the present invention, since the discharge pressure is introduced into the pressure chamber via the control valve, the contact between the drive side clutch plate and the driven side clutch plate can be adjusted by an arbitrary pressure. Can be prevented.

〔Example〕

 Hereinafter, the present invention will be described with reference to examples.

FIG. 1 shows an embodiment of the clutch system of the present invention.
The refrigeration cycle for vehicle air conditioning includes a condenser 3 for liquefying and condensing the high-temperature and high-pressure refrigerant discharged from the compressor 2, a liquid tank 5 having a desiccant for absorbing and removing moisture in the liquid refrigerant, and adiabatic expansion of the liquid refrigerant. It comprises an expansion valve 6 in a spray state, and an evaporator 7 in which the liquid refrigerant in a spray state is vaporized and exchanges heat with the surroundings. A clutch body 1 according to the present invention is provided at an end of the compressor 2, and power from a prime mover E is transmitted to the clutch 1 via a belt. And this clutch 1
The start, operation, and stop of the compressor 2 are performed by the intermittent action of. Here, the clutch system according to the present invention will be described. The clutch system according to the present invention is a system for utilizing the high pressure of the refrigeration cycle as the clutch connecting force. The clutch system 1 transmits power to the compressor 2 by frictional force. It comprises a differential pressure switch 4 for detecting a differential pressure between the two, and a control circuit 9 (hereinafter referred to as an ECU) for controlling the on / off of the compressor 2 and the clutch continuous time by various input signals. The control circuit 9 receives signals from various sensors as signals for performing control. That is, a vehicle interior temperature sensor 100 that detects a cooling load required for the compressor, a throttle opening sensor 110 that detects a load state of an automobile driving engine,
An engine speed sensor 120 and a compressor speed sensor 130 used for calculating an actual gear ratio of the engine, and a vehicle speed sensor 140 for detecting an operating state of the vehicle are provided.

Next, the structure of the clutch body 1 will be described with reference to FIG. The clutch body 1 is a front head cover of the compressor 2
A ball bearing 12 is provided on a cylindrical support member 11 formed integrally with 10, and an outer ring of the ball bearing 12 is fitted with and fixed to a drive pulley 13 rotated by a motor via a belt. Further, the drive pulley 13 is provided with a screw portion 13a, and a friction pressure bonding plate 38 is fixed to the drive pulley 13. Further, a piston 14 is inserted into the front head cover 10, and two O-rings 14a and 14b are mounted for sealing the swinging part.

Further, a coil serving as driving means for driving a piston fixed to the cylindrical support member 11 is provided in the cylindrical space inside the piston 14.
15 has been inserted. And when the compressor stops, the coil
The suction space 16 formed by the piston 15 and the piston 14
Thereby, it communicates with the suction chamber 10a at the head front.

A control valve 18 is provided between the coil 15 and the piston 14.

Here, the structure of the control valve will be described with reference to FIG. The control valve 18 is formed in the piston 14 and is inserted into a hole 18a communicating with the suction space 16, and press-fits the plunger 19 for pressing the ball 22 rightward in the drawing, a pressing spring 20, and the front head cover 10. It is composed of a fixed valve seat 21, a return bush 23 for pressing the ball 22 leftward, and a pressing spring 24. The piston 14 is provided with a suction chamber seat 25 and the valve seat 21 is provided with a high-pressure chamber seat 26. The right space 26a of the seat 26 passes through the center passage of the return bush 23, and communicates with the high pressure side space 28 of the air conditioner system via the rib groove 27 provided on the compressor 2 side of the head front 10. Further, the left space of the seat 25 communicates with the suction space 16 through a passage provided in the plunger 19.

The configuration will be further described with reference to FIG. A bearing 29 is provided at the tip of the piston 14, and a plurality of straight pins 31 are provided in a circumferential direction on a holder 30 of the bearing. The bearing holder 30 is press-fitted and fixed to the inner peripheral surface of the bearing 29, and has a dimensional relationship slidable in the left-right direction in the drawing with respect to the cylindrical inner peripheral portion 13b of the pulley 13. A plurality of springs 32 are provided in the circumferential direction between the bearing holder 30 and the rib 13c of the pulley 13 as means for urging the piston 14 against the bottom surface of the head front 10. Further, a friction pressing plate 33 which is a driving side clutch plate is press-fitted and fixed to the tip of the straight pin 31, and the friction pressing plate 33, the straight pin 31, the bearing holder 30,
The bearing 29 and the piston 14 are configured to be integrally movable in the front-rear direction of the compressor 2.

The shaft 2a of the compressor 2 has a hub 34 which is a spline-fitted driven clutch plate, and the hub 34 is formed with a spline and an outer peripheral portion 36 of the hub 34 having friction materials 35 adhered to both surfaces. It is divided into a hub inner peripheral portion 34 and the two portions are connected by a rubber hub 37.

Here, when the compressor 2 is stopped, a predetermined clearance is set between the friction material 35 and the friction pressing plate 38, and between the friction material 35 and the friction pressing plate 33, a predetermined clearance is set. Intermittent is possible.

The operation of the clutch system will be described below in detail with reference to FIGS.

As an initial state, it is assumed that a long time has elapsed since the compressor 2 was stopped before the operation of the clutch, and the high and low pressures of the refrigeration cycle are completely balanced.

When the vehicle prime mover is driven, the drive pulley 13 is rotated by a belt (not shown), and the friction pressure bonding plate 38, the bearing holder 30, the inner ring of the bearing 29,
The straight pin 31 and the friction pressing plate 33 start rotating.
However, in the initial state, the suction space 16 communicates with the suction chamber space 10a of the compressor through the passage 17. Therefore, the piston chamber space 14c and the suction space 16 are pressure-balanced, and no force due to gas pressure acts on the piston 14. Accordingly, the piston 14 is pressed rightward in the figure by the spring 32 and is stopped at the bottom of the head front 10. As a result, the friction pressing plate 33, the friction plate 35, and the friction pressing plate
Since a certain amount of clearance is maintained between 38 and the friction plate 35, the driving force is not transmitted to the shaft 2a of the compressor.

Next, the operation when the A / C switch in the vehicle compartment is turned on will be described. When the A / C switch is turned on, a relatively large current (for example, 8 to 10 A) is supplied to the coil 15. Therefore, the bearing 29, the holder 30, the straight pin 31, and the friction pressing plate 33, which are integrally fitted and formed with the piston 14, move to the left in the drawing and come into contact with the friction pressing plate 38 via the friction plate 35. Will move up to. As a result, the friction plate 35 is a friction pressure bonding plate.
The driving force transmitted from the engine through the belt is sandwiched between the friction pressing plate 33 and the friction pressing plate 33.
And transmitted to the compressor drive shaft 2a via the hub inner circumference 34,
The compressor will start rotating.

Here, the control valve 18 when a large current is supplied to the coil 15
3 will be described with reference to FIGS. When the coil 15 is energized as shown in FIG.
Is the end face 15a of the coil against the force of the pressing spring 20.
Will be sucked up. This state is shown in FIG.
These are shown in (b) and (c). FIG. 4A shows a state before the coil 15 is excited, and FIG.
FIG. 4 (c) shows the state after the piston 14 is actuated. When the plunger 19 is actuated on the coil end face 15a as shown in FIG. 4 (c), the ball 22 is moved by the pressing spring 24 and the return bush 23 to the suction chamber sheet.
It will be pressed against 25. As a result, the pressure chamber 200 is formed by the piston and the valve seat, whereby the high-pressure seat portion 26 is opened, and the piston chamber space 14c and the groove 27 are opened.
And the high pressure side space 28 of the system is in communication.
Further, the suction space 16 and the piston chamber space 14c are shut off by the suction chamber seat portion 25.

Here, the state of the compressor 2 starts to rotate by energization of the coil 15, and as a result, the pressure in the high-pressure side space 28 of the refrigeration cycle gradually increases, and the pressure is increased by the operation of the control valve 18. This will act on the room space 14c. As a result, the suction space 16 and the piston chamber space 14
The gas pressure generated by the pressure difference from c
9, through the holder 30, the straight pin 31, and the friction pressing plate 33, it acts between the friction pressing plate 38 and the friction plate 35 so that the friction plate 35 is interposed therebetween, so that the shaft of the compressor 2a is continuously rotated by the belt. Become. Therefore, the pressure difference between the high pressure and the low pressure increases, and the force acting on the piston 14 increases in proportion to the pressure difference.

When the differential pressure between high and low pressures reaches a certain value (for example, 2 kg / cm ² ) by the differential pressure switch 4 shown in FIG. 1, the current value to the coil 15 is changed to the ON state of the control valve 18 (the seat portion). 25 is closed,
The current value is reduced to only a current value necessary and sufficient to hold the sheet portion 26 open. The meaning of the constant differential pressure set by the differential pressure switch is the minimum differential pressure necessary for driving the compressor, and the time until this differential pressure is generated is extremely short (in units of seconds). Therefore, although the value of the current supplied to the coil 15 is relatively large, the power consumption can be extremely small.

When the refrigeration cycle is in a stable state after the start of rotation of the compressor, the relationship between the differential pressure between high and low pressures of the refrigeration cycle and the drive torque (center value) of the compressor is as shown in FIG.
The clutch allowable transmission torque in this case is also shown in FIG. 5, but as will be understood, the drive torque of the compressor increases. As the compression ratio becomes higher, the allowable transmission torque also increases, and the force obtained by the gas pressure is very large, so that a large transmission torque can be obtained. Therefore, it is possible to prevent the occurrence of slippage (insufficient torque capacity) under low-speed and high-pressure conditions (slow running in an urban area under the scorching sun) seen in a conventional electromagnetic clutch or the like.

Next, the clutch ON-OFF control after the vehicle interior temperature reaches the set value by the operation of the A / C will be described.

The case where the clutch is turned off for cooling capacity control will be described below. When turning OFF, this is achieved by stopping the energization of the coil 15 and switching the control valve 18. The operation of the control valve 18 at this time will be described with reference to FIGS. When the power supply to the coil is stopped in FIG. 4 (d), the suction force between the coil end surface 15a and the plunger 19 disappears, so that the ball 22 and the return bush 23 are pushed rightward by the spring force 20, The seal part 25 is opened. As a result, the high-pressure gas filled in the piston chamber space 14c flows into the suction space 16 and, as shown in FIG.
22 seals the seal portion 26. As a result, the high-pressure gas does not flow into the piston chamber space 14c, and has the same pressure as the suction chamber space 16. As a result, the force of the gas pressure on the piston 14 is balanced, so that the piston 14 is pushed back to the bottom of the head front 1 by the force of the spring 32.
As a result, a clearance is generated between the friction pressing plate 38, the friction pressing plate 33, and the friction material 35, power transmission to the shaft 2a of the compressor is cut off, and the compressor stops.

After the compressor is stopped, if the compressor needs to be restarted due to a rise in vehicle interior temperature, a low current (less than 1 A) for operating the control valve 18 is supplied to the coil 15. Here, FIG. 4 (a)
As shown in the figure, the distance (air gap) between the end face 15a of the coil 15 and the end face 14d of the piston 14
Because the distance between 5a and plunger 19 is set small,
As a result of the preferential flow of the magnetic flux by the coil to the plunger 19, the plunger 19 moves to the left, and the state shifts from FIG. 4 (b) to FIG. 4 (c). The compressor 2 operates due to the pressure difference between the chamber 2 and the suction chamber space 16 flowing into the chamber space 14c. Normally, in the ON-OFF control in the air conditioner system, the clutch is turned ON from OFF.
The interval until can not be long. For this reason, since the differential pressure (residual pressure) between the high and low pressures after the clutch is turned off cannot be less than 2 kg / cm ^2, all the clutch operations in the ON-OFF control are performed with the high and low residual pressure differences in the refrigeration cycle. It becomes possible. From the viewpoint of power consumption, the required current value is an extremely low current value required to operate the control valve 18, which is sufficient to be about 1/3 or less of the power consumption of a normal electromagnetic clutch. be able to.

Next, the operation of the compressor clutch of the present invention will be described with reference to the flowchart shown in FIG.

First, a comparison is made between the vehicle interior temperature T of an automobile or the like detected by a temperature sensor or the like and the set temperature To. (Step S1) When the vehicle interior temperature T is higher than the set temperature To, the differential pressure between the high-pressure side pressure Pd and the low-pressure side pressure Ps of the compressor is determined by the differential pressure switch 4.
To detect. (Step S2) If the differential pressure is lower than the reference pressure Po, EC
A current A _{1 that} allows the end face 14d of the piston 14 to sufficiently attract the end face of the coil 15a to the coil 15 provided on the clutch 1 via U9.
Is applied, and the end face 14d of the piston 14 and the coil end face 15a are sucked. (Step S3) When the pressure difference between the high-pressure side pressure Pd and the low-pressure side pressure Ps exceeds the reference pressure Po, the piston
The 14, it is not necessary to flow a current A ₁ is the compressor 2 of the coil 15 so sufficient force is thus obtained to drive the drive shaft 2a. Therefore, the plunger 19 to the coil 15 by supplying a minimum current value A ₂ contactable to the coil end surface 15a engage the clutch by ECU 9.

Further, when the differential pressure is greater than the reference pressure Po at the step S2, by passing a current A ₂ in the coil 15a through the ECU 9, to connect the clutch is brought into contact with the plunger 19 and the coil end surface 15a.

Further, when the vehicle interior temperature T is lower than the set temperature To, no current flows through the coil 15. (Step S8) FIG. 6 (b), in (c) showed a comparison of the magnitude between the current value A ₁ and A _2. As it is apparent from the figure, the current value A ₁ has a very large value than the current value A _2. However, the differential pressure of the high pressure side and low pressure side of the compressor in the present invention for use in a clutch connection may be flowed to the short coil 15 as a current value A ₁ is a high current FIGS. 7 (b).

Next, effects of the clutch system of the present invention will be described below. In the above-mentioned clutch ON-OFF control, the connection time of a conventional electromagnetic clutch is usually as extremely short as 0.03 seconds. Under such operation of the clutch, a sudden change in torque when the clutch is engaged is transmitted to the E / G, the drive system, the vehicle body, and the occupant, and the driver feels this as an unpleasant connection feeling, which has been a problem. Actual vehicle evaluations have shown that this is particularly noticeable when the E / G is rotating at high speed in low-speed gears. Therefore, in the present invention, as described above, the ON-
At the time of OFF control, paying attention to the fact that all clutches can be connected by the high and low pressure difference (residual pressure) of the refrigeration cycle,
The residual gas pressure in the high-pressure side space 28 shown in FIG. 2 is controlled by the control valve 18 through the rib groove 27 as shown in FIG.
At the time of introduction into 14c, a throttle for gas flow control by an orifice was provided in a part of the rib groove passage 27 from the high pressure side space 28 of the control valve 18.

As a result, the residual high-pressure gas in the high-pressure side space 28 does not flow into the piston chamber space 14c in a short time even when the control valve 18 is opened. The pressure rise (gradient of the pressure rise) per unit time of the stop piston chamber space 14c becomes gentle, and as a result, the friction pressing plate 33, the friction pressing plate 38 and the friction material 35
Slip will occur between them. As a result, the rate of change (differential value) of the torque transmitted to the drive shaft 2a of the compressor 2 per unit time becomes small, so that a large torque change does not occur. FIG. 7 shows this state by the shaft torque of the drive shaft 2a of the compressor 2, and compares the present invention with the conventional electromagnetic clutch 4.

As is clear from FIG. 7, the shaft torque of the conventional compressor shows a peak value as shown at point A in FIG. 7, so that an unpleasant coupling shock cannot be avoided. However, by employing the clutch of the present invention, it is possible to perform a favorable connection in which the shaft torque of the compressor does not show a peak value as shown at point B in FIG.

As described above, the occupant does not experience the unpleasant connection shock accompanying the ON / OFF of the clutch, and can enjoy a comfortable drive. Also, regarding the operating noise at the time of clutch connection, in the case of an electromagnetic clutch, an iron-based material had to be used due to the magnetic path, and as a result, the connection of the clutch was heard as a sound together with the shock. . However, the friction surface in the present invention can significantly reduce the operation noise itself due to the combination of the metal and the friction material.

Also, regarding the durability of the friction material against repeated sliding, a friction material for a brake may be applied, and there is no need to use a new friction material.

The above is the story of intermittent clutch operation during A / C operation.
When / C is turned off and left for a long time before restarting, it is almost impossible to expect a differential pressure to make the residual pressure. Therefore, in such a case, the coil
By applying a relatively large current to the motor 15 for a very short time, the compressor can be operated regardless of the state of the air conditioner cycle.

As described above, the present clutch system provides a smaller and lighter clutch system with a larger permissible transmission torque than the conventional electromagnetic clutch, and has been a problem during clutch ON-OFF control. The connection shock is solved by using a simple method of controlling the flow rate of the high-pressure residual gas by using a fixed throttle.

Of course, when performing finer and finer control without using the open control as described above, the E / G rotation speed and the Comp. Rotation speed are detected as shown in FIG.
If the duty control (feedback control) is performed, the flow control of the high-pressure residual gas can be optimally controlled irrespective of the running state and the gas pressure state.

[Brief description of the drawings]

1 is a configuration diagram of a refrigerating cycle, FIG. 2 is a cross-sectional view of a clutch for a compressor of the present invention, FIG. 3 is an enlarged view of the periphery of a control valve, FIG. FIG. 6 is a relationship diagram showing the relationship between pressure and torque, FIG. 6 is a flowchart showing the operation of the present invention, and FIG. 7 is a characteristic diagram showing the effect of the present invention. 13 ... pulley, 14 ... piston, 15 ... drive means (coil), 16 ... pressure chamber (suction space), 18 ... control valve, 19 ...
… Plunger, 32… spring, 33… drive side clutch plate (friction pressing plate), 34… driven side clutch plate (hub).

Claims (3)

(57) [Claims] 1. A pulley rotatably held on a housing and rotated by receiving power from the outside, a drive-side clutch plate rotating with the pulley, a drive-side clutch plate opposed to the drive-side clutch plate, and a compressor drive. A driven clutch plate that rotates integrally with a shaft; and a driven clutch plate that is disposed to face the driven clutch plate or the driving clutch plate, and that contacts the driven clutch plate and the driven clutch plate in accordance with the axial displacement thereof. A piston that changes a force, a driving unit that drives the piston in a direction to increase the contact between the driving-side clutch plate and the driven-side clutch plate, and one of the pistons facing the driven-side clutch plate. A pressure chamber provided on a surface; a control valve for controlling communication between a discharge pressure side of the compressor and the pressure chamber; A spring for biasing the clutch in a direction to reduce contact with the side clutch plate. 2. The compressor clutch according to claim 1, wherein said drive means is a coil that generates a magnetic flux when energized. 3. The compressor clutch according to claim 1, wherein said control valve is provided with a throttle.