JPS6392825A - Friction clutch - Google Patents

Abstract

PURPOSE:To enable the whole clutch to be miniaturized, by pushing or separating input side friction plates toward or from output side friction plates by means of the discharge pressure from a hydraulic pump, so that a large spring load is not added to a piston at any time. CONSTITUTION:A part of operating oil discharged from a discharge communicating hole 227 by the displacement of a spool is introduced into a piston push-back chamber 407 side. Consequently, a pressure plate 408 and an input side friction plates 417 are separated from an output side friction plates 416, and the torque of an input side shaft 102 is not transmitted to an output side shaft 530. If the spool displaces more than a prescribed value, the discharge side pressure of a pump is introduced into a piston push-out chamber 406, and inversely the suction side pressure is introduced into the piston push-back chamber 407. Consequently, a piston 414 displaces to the pressure plate 408 side. Receiving this displacement, the pressure plate 408 and input side friction plates 417 displace so as to come into contact with the output side friction plates 416. Accordingly, it is not necessary to burden the friction plates always with a large spring load, and the whole clutch can be miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a friction clutch, and is useful, for example, for transmitting rotational driving force from an automobile engine to a refrigerant compressor for an automobile air conditioner. be.

[Conventional technology and its problems]

Conventionally, in a friction clutch, transmission of input rotational force is controlled by contacting and separating an input-side friction plate and an output-side friction plate. A piston is used to release pressure from the input friction plate toward the output friction plate (for example,
6427).

The force for pushing the piston back to its original position was obtained using a coil spring or the like. In other words, high pressure from the coil spring is always applied to the piston, and when the piston releases pressure from the input side friction plate toward the output side friction plate, the piston should be given enough pressure to overcome the spring force of the coil spring. was.

The piston had to be moved back while pushing back the oil present in the rings. Because this pressure loss increases as the rotation increases and the pressure receiving area of the piston is quite large, the retraction spring was quite large. As described above, since a large spring must be built into the clutch portion, the conventional clutch cannot avoid increasing its size. Furthermore, since the piston does not operate unless it overcomes the force of the spring, the hydraulic pump also requires a large discharge hydraulic pressure.

[Problem that the invention seeks to solve]

The present invention was devised in view of the above points, and an object of the present invention is to enable a piston for driving a friction plate to efficiently utilize hydraulic pressure to drive the friction plate.

[Configuration and operation]

In order to achieve the above object, in the present invention, a piston push-back chamber and a piston push-out chamber are formed in a cylinder that slidably accommodates a piston. Hydraulic pressure from a hydraulic pump can be supplied to both chambers. Furthermore, a switching valve for switching the supply of hydraulic pressure is provided so that the discharge pressure from the hydraulic pump can be selectively supplied to either the piston push-out chamber or the piston push-back chamber.

That is, when the clutch is connected, the discharge pressure from the hydraulic pump is guided to the piston pushing chamber side, the piston is displaced by this discharge pressure, and the input side friction plate is pressed against the output side friction plate. Conversely, when the clutch is disengaged, the discharge pressure from the hydraulic pump is guided to the piston pushback chamber. This pushes the piston back and causes the input side friction plate to be separated from the output side friction plate.

〔Effect of the invention〕

With the above configuration, the present invention Pj! According to the friction clutch, a large spring load is not constantly applied to the piston. Therefore, in the friction clutch of the present invention, the overall shape of the clutch can be reduced in size, and the structure of the clutch portion can be simplified.

〔Example〕

Hereinafter, the clutch of the present invention will be explained based on the drawings.

In FIG. 1, reference numeral 101 denotes a pulley, which rotates by receiving the rotational force of an automobile engine (not shown) via a V-belt. 1
A bearing 04 supports the rotation of this pulley, and is installed on the front housing 105. The rotation of the pulley 101 is transmitted to the input side 102 via the rotary plate 103. Note that the rotary plate 103 is mounted on the shaft 102 with a bolt 1.
06 and a spline. Further, a shaft seal 107 is provided between the front housing 105 and the shaft 102 to prevent internal refrigerant and the like from flowing out along the shaft 102.

A pump housing 204 is disposed on the side of the front housing 105, and this pump housing 204 accommodates the trochoid pump 200 inside. The trochoid pump 200 has a pump rotor 280 fixed on the shaft 102 and operates in response to rotation of the shaft 102. As shown in FIG. 3, a pump discharge chamber 205 and a pump suction chamber 210 are located opposite the side surface of the pump rotor 280.
is formed. The pump suction chamber 210 communicates with the oil tank 213 via a suction communication hole 228 formed in the pump housing 204. In addition, the pump housing 20
4 is formed with a discharge communication hole 227 and an oil recovery hole 229, and the discharged oil in the pump discharge chamber 205 is returned to the oil tank 21 through the communication hole 227 and the oil recovery hole 229.
Returned to side 3. Note that a solenoid pulp 300 is disposed between the oil recovery hole 229 and the discharge communication hole 227, and the discharge communication hole 227 is opened and closed by this valve 300.

The pump housing 204 has a cylinder 430 on its side.
A piston 41 is formed within this cylinder 430.
4 is slidably disposed.

The piston 414 and cylinder 430 are kept oil-tight by an O-ring. Further, the open end of the cylinder 430 is closed by a closing plate 402.

The closing plate 402 is connected to the pump housing 2 by a circlip.
04 between the closing plate 402 and the inner surface of the cylinder 430 and between the closing plate 402 and the piston 414.
Sealed by a ring.

A valve mechanism 300 as shown in FIG. 3 is disposed within the pump housing 204. This valve mechanism 300 includes a piston pushing chamber 40 closed on one side of a piston 414.
6 and the piston push-back chamber 407 formed on the other side of the piston 414 are switched and controlled.

The electric hole 300 has a spool 324 that is slidably housed, and this spool 324 connects to the discharge communication hole 227,
Suction communication hole 228, communication hole 31 with piston push-back chamber
9 and the communication hole 318 with the piston extrusion chamber.

A pressure chamber 353 is formed at one end of the spool 324, and is connected to this pressure chamber 353 through the discharge pressure introduction hole 320.
The discharge pressure of the pump 200 is supplied. Also, spool 3
A low pressure chamber 352 is formed at the other end of 24, and this low pressure chamber 3
52 communicates with the suction communication hole 228, through which the suction pressure of the pump 200 is introduced.

Further, a spring 321 is disposed in the low pressure chamber 352, and the spool 324 is pressed toward the pressure chamber 353 by the spring 321.

As shown in FIG. 4, the spool 324 includes first, second and
Third piston portions 391, 392, and 393 are formed. Further, a first switching chamber 395 and a second switching chamber 396 are formed between each piston portion. Furthermore, a communication hole 350 is formed inside the spool, and the first switching chamber 395 and the low pressure chamber 352 communicate with each other through the communication hole 350.

Piston 414 presses pressure plate 408 via bearing 415. pressure plate 408
The input side friction plate 417 is disposed on the outer periphery of the shaft 102 so as to be displaceable in the shaft axial direction. That is,
These pressure plates 408 and input side friction plates 417
rotates integrally with the shaft 102, but can be displaced in the axial direction of the shaft 102.

An output side friction plate 4 is located at a position opposite to the input side friction plate 417.
16 are arranged. This output side friction plate 416 is fixed to the clutch blade receiver 409. The clutch plate receiver 409 also connects to the output shaft 53
Fixed to 0.

FIG. 2 is a perspective view showing this clutch section, and there is a spacer 401 between the input side friction plate 417 and the output side friction plate 416.
is installed. This spacer 401 has both friction plates 41
6,417 are kept separated for a predetermined period.

The output shaft 530 is connected to the rotor 518 of the compressor 500, and the rotor 518 rotates within the housing 501 under the rotational force of the shaft 530. A vane groove is formed in the rotor 518, and the vane 502 is slidably disposed within the vane groove. Therefore, a compression space is formed by the inner surface of the rotor 518 outer peripheral housing 501 and the vane 502, and this compression space is
The volume increases or decreases as the unit rotates. The outer periphery of the clutch portion also serves as a suction chamber 503, into which refrigerant from an evaporator (not shown) of the refrigeration cycle is sucked. Then, the refrigerant in the suction chamber is transferred to the side plate 55.
It is sucked into the compression chamber through the suction hole formed in 1. The refrigerant compressed in the compression chamber is then discharged into a discharge chamber 504 from a discharge hole (not shown), and then discharged into an oil separation chamber 506 formed in the rear housing 552 via a discharge communication passage 505. After the lubricating oil is separated in this oil separation chamber 506, the refrigerant is discharged to the condenser side (not shown) of the refrigeration cycle.

Next, the operation of the clutch mechanism having the above configuration will be explained.

First, when the clutch is disengaged, the solenoid valve 300 is open. Therefore, as shown in FIGS. 5 and 7, the actuation discharged from the pump 200 is returned to the oil tank 213 via the valve 300. In this case, the load applied to pump 200 is
The pump 200 is operated almost under no load, with only pressure loss occurring when the pump 200 passes through the passage. Therefore, the pressure within the discharge communication hole 227 does not increase much.

Therefore, the pressure supplied to the pressure chamber 353 via the discharge pressure introduction hole 320 does not increase much, and the biasing force of the spring 321 becomes larger. Therefore, the spool 324 is pressed toward the pressure chamber 353 by the spring 321, and the position is maintained in this state.

Therefore, as shown in FIGS. 5 and 7, the discharge communication hole 2
A part of the working oil discharged from the second switching chamber 39
6 into the piston push-back chamber 407 side from the passage 319. On the other hand, the piston extrusion chamber 416
8 and the suction communication hole 2 of the pump 200 via the low pressure chamber 350.
It connects to 28. Therefore, the piston push back chamber 407
The suction side pressure of the pump 200 is applied to.

Based on this pressure difference, the piston 414 is displaced toward the extrusion chamber 406 side.

This is the state shown in FIG. 1, and the piston 406 no longer presses the pressure plate 408.

Therefore, the pressure plate 408 and the input side friction plate 4
17 is detached from the output side friction plate 416 and is attached to the shaft 102.
The rotational force of is not transmitted to the output shaft 530.

Next, the clutch engagement will be explained based on FIG. 6 and FIG. 8.

In this case, the valve mechanism 300 blocks the discharge communication hole 227 and the oil recovery hole 229. Therefore, pump 200
The discharged working oil cannot return to the oil tank 213 side, but flows to the pressure chamber 353 side via the passage 320. That is, the discharged oil is stored in 353,
The pressure inside the pressure chamber 353 is increased. Due to this pressure increase, the spool 324 compresses the spring 321 and is displaced toward the low pressure chamber 352 side.

If the spool 324 is displaced by a predetermined value or more, the first switching chamber 39
5 opens with passage 319. Here, the first switching chamber 395
Since the communication hole 350 is open in , the passage 319 communicates with the low pressure chamber 352 via the communication hole 350.

On the other hand, the second switching chamber 396 includes the passage 318 and the discharge communication hole 2.
It will communicate with 27. Therefore, the piston push-back chamber 407 includes the passage 319, the first switching chamber 395, and the communication hole 35.
0, it communicates with the suction communication hole 228 of the pump via the low pressure chamber 352.

Further, the pump purification chamber 405 communicates with the discharge communication hole 227 of the pump via the im path 318 and the second switching chamber 395. Therefore, in this state, the pressure on the discharge side of the pump is introduced into the piston push-out chamber 406, and conversely, the pressure on the suction side is introduced into the piston push-back chamber 407.

Therefore, the pressure applied before and after the piston 414 is reversed, and the piston 414 is displaced toward the pressure plate 408. In response to this displacement, the pressure plate 408
And the input side friction plate 417 is displaced so as to come into contact with the output side friction plate 416.

Therefore, a frictional force is generated between the pressure plate 408 and the input side friction plate 417 and the output side friction plate 416, and the rotational force of the shaft 102 is transmitted to the output side shaft 530. When the rotational force is transmitted to the output shaft 530 in this way, the compressor receives the rotational force and suctions and compresses the refrigerant.

Next, a description will be given based on a second embodiment of the clutch of the present invention. In the above-mentioned embodiment, the valve mechanism 300 used a spool 324 consisting of a → direction valve, but this ninth
In the illustrated embodiment, the spool 324 is connected to the piston ejection chamber 4.
06 is switched between the suction communication hole 228 and the discharge communication hole 227 of the pump 200. The operation of the clutch according to the second embodiment will be explained based on FIGS. 10 and 11. FIG. 10 shows the state when the clutch is disengaged. In this case, valve 300 is open.

Therefore, the pump 200 is operated with almost no load,
The pressure on the discharge communication hole 227 side also does not increase much. That is, in this state, the pressure in the pressure chamber 353 is lower than the set pressure of the spring 321, and as shown in FIG. 10, the spool 324 is also displaced upward by the amount shown in the figure. Therefore, the piston pushing chamber 406 communicates with the low pressure chamber 352 via the passage 318. That is, the low pressure side pressure of the pump 200 is supplied to the piston pushing chamber 406. Note that the piston push-back chamber 407 is always supplied with the discharge side pressure of the pump 200. Therefore, a pressure difference occurs before and after the piston 414, and this pressure causes the piston 414 to
14 is displaced. FIG. 9 shows the state when the clutch is disengaged. In this state, the pressure plate 408 and the input side friction plate 417 are separated from the output side friction plate 416 by the spring force of the spacer 401.

Valve 300 is closed when the clutch is engaged.

As a result, the working oil discharged from the pump 200 does not return to the oil tank 213 side, but is supplied to the piston push-back chamber 407 via the passage 319, and is further supplied to the pressure chamber 353.
be introduced within. Therefore, the pressure within the pressure chamber 353 becomes high, overcoming the force of the spring 321 and displacing the spool 324 downward in FIG. 11. With this displacement, the discharge communication hole 22 of the pump 200 as shown in FIG.
7 communicates with the passage 318 via the pressure chamber 353.

That is, in this state, the discharge pressure of the pump 200 is supplied not only to the piston push-back chamber 407 but also to the piston push-out chamber 406 side.

As shown in FIG. 9, the pressure receiving area of the piston pushing chamber 406 is significantly larger than the pressure receiving area of the piston pushing back chamber 407. Therefore, a difference in pressing force occurs between both surfaces of the piston 414, and based on this difference, the piston 414
is displaced and presses the pressure plate. Along with this fluctuation of the pressure plate 408, the input side friction plate 407
The frictional force between the output side friction plate 416 and the output side friction plate 416 increases. As a result, the rotational force of the shaft 102 is transmitted to the output shaft 530 side.

Note that in both the first and second embodiments described above, the spool 32
Although the spring 321 is used for the return of the piston 4, since the pressure receiving area of the spool 324 is much smaller than that of the piston 414, the set pressure required for the spring 321 can also be small. Therefore, this spring 3
21 causes no loss of output of the pump 200.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the clutch of the present invention, FIG. 2 is a perspective view showing the components of the clutch shown in FIG. 1, and FIG. 3 is a sectional view showing the switching valve part shown in FIG. 1. Figure 4 is a sectional view showing the spool shown in Figure 3, Figures 5 and 6 are block diagrams showing the operation of the switching valve shown in Figure 1, and Figures 7 and 8 are the switching valve shown in Figure 1. FIG. 9 is a cross-sectional view showing another embodiment of the clutch of the present invention, and FIGS. 10 and 1I are configuration diagrams showing the operation of the switching valve shown in FIG. 9. 102...Input side shaft, 200...Oil pump, 227...Discharge communication hole, 228...Suction communication hole. 318.319...Pressure communication passage, 324...Spool, 401...Spacer, 416...Output side friction plate. 417...Input side friction plate, 414...Piston, 4
30...Cylinder, 530...Output side shaft.

Claims (1)

[Claims] An input side shaft, an input side friction plate that is arranged on the shaft so as to be slidable in the shaft axial direction and rotates integrally with the shaft, and an input side friction plate that is arranged opposite to this input side friction plate and when it comes into contact with the input side friction plate. an output-side friction plate that transmits the rotation of the input-side friction plate to the output-side shaft; a spacer that biases the input-side friction plate in a direction away from the output-side friction plate; and a spacer that applies the output-side friction to the input-side friction plate. a piston that provides displacement in the plate direction; a cylinder that slidably accommodates the piston and forms a pushing chamber at one end of the piston; and a cylinder pushing back the piston at the other end of the piston; an oil pump that operates in response to the rotational force of a side shaft and sucks and discharges working oil; a passage that guides the working oil discharged from the oil pump to the piston pushing chamber side; and a passage that guides the working oil discharged from the pump. A friction clutch comprising: a passage leading to the piston push-back chamber; and a switching valve that selectively switches and supplies working oil discharged from the pump to either the piston push-back chamber or the piston push-back chamber.