JPH03189425A - Control device for hydraulic clutch - Google Patents

Abstract

PURPOSE:To prevent the drag of a clutch at a low temperature by controlling hydraulic pressure fed to the inside of a clutch cover with a back pressure valve internally having a shape memory alloy spring in such a way as to increase relief pressure when clutch oil temperature is low. CONSTITUTION:When outside temperature is low, oil temperature is naturally low and oil viscosity increases. In this state, a shape memory alloy spring 143 in a back pressure valve 140 is compressed and deformed, and a sleeve 144 advances due to the force of the first spring 145, thereby increasing the set load of the second spring 146. As a result, valve body 142 throttles a relieve passage 141, raises the pressure of pressure oil PC2, and expands a gap between a clutch cover 6 and a clutch disc 3, thereby decreasing the torque effect of clutch drag due to oil viscosity. When oil temperature rises, the aforesaid spring 143 expands, thereby controlling the pressure oil PC2 at the predetermined constant level.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industry> Second Field of Application The present invention relates to a control device for a hydraulic clutch of an automobile.

<Conventional technology> A clutch disc is mounted on the input shaft of a flywheel fixed to the engine crankshaft.
A hydraulic clutch is known, for example, from Japanese Utility Model Application Laid-Open No. 59-88524, in which a hydraulically actuated piston provided on the rear surface of the clutch presses the clutch disc in the clutch engagement direction and a spring force presses the clutch disc in the clutch disengagement direction.

In the above-mentioned hydraulic clutch, a hydraulically actuated piston is used to engage the clutch, but a spring is used to disengage the clutch, so there is a problem in the responsiveness of clutch engagement and disengagement.

Further, the above-mentioned hydraulic clutch is a so-called dry type, and requires measures to prevent wear of the clutch disk, which is repeatedly and severely pressed by a hydraulic piston.

In order to improve these problems, the inside of the clutch cover in which the clutch disc and hydraulic piston are installed is sealed, and oil at a predetermined pressure supplied from an oil pump is circulated within this sealed space. A hydraulic clutch is provided in which pressure oil always acts on a hydraulic piston in a backward direction to disengage the clutch, and a hydraulic pressure higher than the oil pressure in the sealed space is applied to the hydraulic piston to connect the clutch. .

<Problems to be Solved by the Invention> However, in the above conventional technology, since the gap between the clutch cover and the clutch disc is constant, the viscosity of the oil increases at low temperatures, resulting in an increase in clutch drag torque. be.

Means for Solving the Problems> The present invention has been made to improve the above-mentioned problems, and its characteristic configuration is that a clutch is installed in a clutch cover connected to the engine crankshaft. In a hydraulic clutch that includes a disc and a piston that presses the clutch disc in the clutch engagement direction, and in which pressure oil that presses the piston in the clutch disengagement direction is constantly circulated and supplied in the clutch cover, the oil in the oil tank is A variable field tht type bong for sucking and discharging; a first circuit communicating with the discharge side of the variable field X type pump and a pressure oil supply side into the clutch cover; and a second circuit communicating with the cylinder of the piston; One circuit includes a first pressure control solenoid valve that controls the pressure in the second circuit to rise and fall, and a spring made of a shape memory alloy to increase the pressure of the hydraulic pressure supplied to the inside of the clutch cover by constricting the relief passage when the temperature is low, and when the temperature is high the pressure is increased. A back pressure valve is provided in which the brightness of the valve body is controlled according to the oil temperature so as to open the relief passage and lower the pressure, and the second circuit is provided with a second pressure control for controlling the supply and discharge of pressure oil to and from the cylinder of the piston. I had installed a solenoid valve.

With the above configuration, when the temperature is low, the valve body of the back pressure valve uses the shape memory action of the spring made of a shape memory alloy to narrow the relief passage, increase the relief pressure, and reduce the pressure oil supplied into the clutch cover. The pressure is increased to actively widen the gap Lm between the clutch cover and the clutch disc, thereby reducing the influence of clutch drag torque.

<Example> Hereinafter, an example of the present invention will be described based on the drawings. FIG. 1 shows the overall structure of a hydraulic clutch, in which 1 is an engine crankshaft, 2 is an input shaft, and 3 is a clutch disk connected to the input shaft 2 by splines.

Reference numeral 6 denotes a clutch cover that is arranged in a sealed manner on the input shaft 28. The clutch disc 3 is disposed within the clutch cover 6, and a piston 11 for pressing the clutch disc 3 against the clutch cover 6 is provided. 1
0 is a cylinder that slidably holds the stone 11;
21 is a spring that presses and biases the piston 11 in the forward direction, and 12 is a rotation preventing member that allows the piston 11 to slide and restricts the rotation direction.

A flex plate 4 is fixed to the crankshaft 1, and a ring gear 5 connected to a starter motor is attached to the outer diameter end of the flex plate. A ring gear 7 for power transmission is fixed to the flex grate 4, and a ring gear 8 that meshes with the ring gear 7 is fixed to the outer surface of the clutch cover 6.

13 is an oil pump, and 14 is a control pulp.

The control valve 14 includes a boat 16 that supplies pressure oil pct to the back chamber of the piston 11 via an oil passage 15;
A boat 19 supplies pressurized oil DC2 to the space 17 in the clutch lever 6 via an oil passage 18, and an oil pump 13 supplies the pressurized oil pc2 in the space 17 through the gap between the front surface of the piston 11 and the clutch disc 3. It has a boat 20 for returning to.

In the hydraulic clutch configured as described above, the rotational power of the crank jabut 1 is transmitted to the clutch cover 6 via the flex plate 4 and the ring gear 7.8.

On the other hand, the pressure oil pc2 from the oil pump 13 is supplied to the space 17 inside the clutch cover 6 from the photo 19, and
The interior is filled with a predetermined amount of pressure oil pc2. The piston 11 then returns to the boat 20 through a gap between the front surface of the piston 11 and the clutch disc 3, thereby performing a circulating action. This pressure oil pc
2, the piston 11 is always pressed in the backward direction away from the clutch disc 3, thereby performing a clutch disengagement action.

In this state, to connect the clutch, pressure oil PCL is supplied from the boat 16 to the back surface of the piston 11 via the oil passage 15. This pressure oil pc1 has a higher pressure than the pressure oil pc2, so that the piston 11 overcomes the pressing force of the pressure oil pc2 and moves forward, presses the clutch disc 3 against the clutch cover 6 and is transmitted to the clutch cover 6. The rotational power of the engine is transmitted to the input shaft 2 via the clutch disc 3.

FIG. 2 shows a device for controlling the hydraulic clutch configured as described above, and its configuration is as follows. 80 is an oil tank, and a filter 180 is installed inside the oil tank.

14 is an oil pump of variable capacity type, and its suction side 9a
and the oil tank 80 are connected through a conduit 190. Further, a first circuit 110 communicating with the oil passage 18 of the hydraulic clutch and a second circuit 120 communicating with the oil passage 15 are branched and connected to the discharge 111j9b of the oil pump 14.

1 The first circuit 110 includes a first pressure solenoid control valve 130 that controls the rise and fall of the pressure in the second circuit 120;
A back pressure valve 140 is provided between the pressure electromagnetic control valve 130 and the oil passage 18 to control the pressure oil PC1 constantly supplied to the space 17 in the clutch cover 1 according to the oil temperature. 141 is connected to the first circuit 110 via the back pressure valve 140.
This is a relief passage connecting the pipe line 190 and the pipe line 190. The back pressure valve 140 includes a sleeve 144 that is pushed forward by a first spring 145 and pushed back in a backward direction by a spring 143 made of a shape memory alloy against the spring 145, and a second spring 146 is interposed in front of the sleeve 144. and a valve body 142 that is pressed forward, and when the temperature is low, the valve body 142 is provided with a relief passage 14.
1 to increase the pressure of the pressure oil PC2 in the first circuit, and when the temperature is high, the relief pressure is automatically controlled in accordance with the temperature so that it expands and lowers the pressure of the pressure oil PC2.

On the other hand, the second circuit 120 is provided with a second pressure control solenoid valve 150 that controls supply and discharge of pressure oil PCI to and from the cylinder 10 of the piston 3.

Incidentally, all of the pressure oil discharged from the 1.2 pressure control solenoid valves 130 and 150 and the back pressure valve 140 is returned to the oil tank 80.

In addition, the space 17 inside the clutch cover 1 and the oil tank 8
It is connected to the filter 180 inside 0 through a conduit 160, and an oil cooler 170 is installed in the conduit 160.

Next, the operation of the above configuration will be explained. oil pump 1
4 is of a variable capacity type, so the eccentricity of the cam ring 93 is controlled in proportion to the flow rate of pressure oil, and a constant flow rate of pressure oil is discharged regardless of fluctuations in the rotational speed.

The first pressure solenoid control valve 130 is normally wide open,
Pressure oil discharged from the oil pump 14 flows into the oil path 110 and is controlled to a constant pressure by the back pressure valve 140. Pressure oil PC2 controlled to this constant pressure is supplied to the space 17 from oil #t18 and clutches the piston 3. Press in the direction of separation. Then, the pressure oil PC2 in the space 17 is returned to the oil tank 8o via the pipe line 160.

That is, the hydraulic clutch uses pressure oil PC2 passing through the oil passage 110.
The clutch is always biased to the disengaged state.

In addition, to connect the hydraulic clutch, a command current is applied from a controller (not shown) to the first pressure solenoid control valve 130 and the second pressure control solenoid valve 150, and the first pressure solenoid control valve 130 is throttled and connected to the second circuit. Increase the pressure of pressure oil PC1 of 1201\. The pressure increase of this pressure oil PC1 is controlled to a higher pressure than the pressure oil PC2, and the second pressure control solenoid valve 15
0, pressure oil PC1 is supplied to the oil passage 15 according to the applied electromagnetic value, and the clutch is controlled to be connected slowly or early according to the driving state and the like.

When the clutch is disconnected from the connected state, the second pressure control m solenoid valve 150 is operated by the pressure oil P supplied to the cylinder 10.
It is switched to discharge CI into the oil tank 80.

Therefore, when the outside temperature is low, the oil temperature is naturally low and the viscosity of the oil is high. In such a case, the back pressure valve 14
0, the shape memory alloy spring 143 is contracted and deformed, the sleeve 144 is moved forward by the force of the first spring 145, and the set load of the second spring 146 is increased. As a result, the valve body 142 throttles the relief passage 141 to increase the relief pressure, increases the pressure of the pressure oil PC2, and closes the clutch cover 6.
The influence of clutch drag torque due to oil viscosity is reduced by widening the gap between the clutch disk 3 and the clutch disk 3. Note that when the oil temperature rises, the shape memory alloy spring 143 moves backward, causing the sleeve 144 to retreat against the force of the first spring 145, weakening the set load of the second spring 146, and lowering the relief pressure. This is to control PC2 to a constant set pressure.

<Effects of the Invention> As described above, according to the present invention, the inside of the clutch cover in which the clutch disc and the hydraulic piston are installed is sealed, and oil at a predetermined pressure supplied from the oil pump is supplied into this sealed space. In a hydraulic clutch in which the pressure oil is circulated, the hydraulically actuated piston is always acted on in a backward direction to disengage the clutch, and a hydraulic pressure higher than the oil pressure in the sealed space is applied to the hydraulically actuated piston to connect the clutch. , the pressure of the pressure oil supplied into the clutch cover is controlled by detecting the clutch oil temperature with a back pressure valve having a shape memory alloy spring inside, and controlling the relief pressure to increase it at low temperatures. Therefore, it is effective in eliminating clutch drag problems caused by oil viscosity at low temperatures.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a sectional view of a hydraulic clutch, and FIG. 2 is a diagram in which a control circuit is integrated with the hydraulic clutch. 2...Input shaft, 3...Clutch disc, 6...
Clutch cover, 10... Cylinder, 11... Piston, 14... Oil pump, 15... Oil path, 17
...Space, 18...Oil passage, 110...First circuit,
120... Second circuit, 130... First pressure control V4 solenoid valve, 140... Back pressure valve, 142... Valve body, 143
...Shape memory alloy spring, 150...Second pressure control m solenoid valve. Patent applicant Rokuhira Ibe, representative of Hino Motors Co., Ltd.

Claims (1)

[Claims] A clutch cover connected to the engine crankshaft includes a clutch disc and a piston that presses the clutch disc in the direction of clutch engagement, and pressurized oil is constantly supplied within the clutch cover to press the piston in the direction of clutch disengagement. In a hydraulic clutch that circulates and supplies oil, there is a variable displacement pump that sucks and discharges oil from an oil tank, a first circuit that communicates between the discharge side of the variable displacement pump and the pressure oil supply side into the clutch cover, and a piston. a second circuit communicating with the cylinder, a first pressure control solenoid valve for controlling the pressure in the second circuit to rise and fall; and a pressure oil pressure supplied to the clutch cover at a low temperature by a spring made of a shape memory alloy. A back pressure valve is provided in which the opening degree of the valve body is controlled according to the oil temperature so that when the temperature is high, the relief passage is narrowed to increase the pressure, and when the temperature is high, the relief passage is opened to decrease the pressure. 1. A control device for a hydraulic clutch, comprising a second pressure control solenoid valve for controlling supply and discharge of pressure oil to and from the hydraulic clutch.