FR2500094A1 - ACTIVATION DEVICE FOR CONTROLLING THE HYDRAULIC OPENING OF A CLUTCH - Google Patents

Abstract

THE PRESENT INVENTION CONCERNS AN ACTIVATION DEVICE FOR THE HYDRAULIC CONTROL OF A CLUTCH. THIS DEVICE INCLUDES AN OIL SUPPLY UNIT HAVING A TANK 1, A PUMP 3, A PRESSURE RESERVE 4 AND A SHUT-OFF VALVE 13. IT IS CHARACTERIZED IN THAT IT ALSO INCLUDES A VALVE DEVICE 6 CONSTITUTED BY A PRESSURE REGULATING VALVE, INCLUDING AN ADJUSTMENT POSITION III LOCATED BETWEEN A LOCKING POSITION I AND A DRAINING POSITION II. A BYPASS 10 IS CONNECTED TO THE ADJUSTING MOTOR 11 AND CONNECTED TO THE SUPPLY TUBING 5. THE DEVICE ALLOWS BY SIMPLE MEANS TO ENSURE ASSISTED DISENGAGEMENT WHEN THE VEHICLE ENGINE IS STOPPED.

Description

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  The present invention relates to an activation device for controlling the hydraulic opening of a clutch, actuated in the closing direction by a spring force, comprising a feed unit.

  of oil comprising a reservoir, a pump, a pressure reserve and a reservoir.

  stopper operating with the pressure reserve, this unit being connected with

  roped to a feed pipe; a valve device mounted between the

  feeding bulwark and return tubing, this device having a positive

  locking position and a flow position for activating a

setting.

  Such a device is known from German Patent Application No. 26 36 982, published before examination. In this device, a magnetic valve

  two-way is mounted in the supply duct connecting the control unit

  provision of oil to the adjusting cylinder. A return duct is de-

  riveted section of conduit connecting the magnetic valve to the cylinder of re-

  This bypass pipe includes a second two-way magnetic valve. To disengage the clutch when the engine is running and when

  the pump is actuated, the magnetic valve mounted in the feed pipe

  It is brought into the flow position II (open position), and the magnetic valve mounted in the return duct is brought into the locking position I (closed position). The pressurized oil flowing into the

  In this way, the mofor regulator pushes the clutch plate

  a lever and a force spring. When the engine is in the

  In the end, the disengagement maneuver is linked to considerable difficulties, since the pump does not supply any pressure energy and, secondly,

  the drive mechanism is locked when a speed is engaged.

  In practice, it is impossible to release a speed, especially on commercial vehicles, when the engine is stopped. For this reason we equip the oil supply unit of the described activation device of a pressure reserve, capable of providing the pressure energy required to disengage, when the engine is stopped. For this operation to be possible, the switching of the two magnetic valves must be done in such a way that the magnetic valve controlling the return duct is pushed back into its locking position I, before the magnetic valve controlling the supply duct and of this also makes the pressure reserve either

  brought back to its flow or opening position II. To avoid the

  accidental cupping of the fluid reservoir under pressure, it is essential

  sand to respect this shift of the valve control. The device described in the aforementioned patent application does not guarantee a safe control of the magnetic valves allowing the disengagement when the engine is at

shutdown.

  The present invention proposes to overcome this drawback

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  by providing an activation device for disengaging even when the engine is stopped, this device being of simple construction and providing significant operational safety. The control part of the device

  be designed in such a way that no error in operation is pos-

  sible. This object is achieved by the device according to the invention characterized in that the valve device is constituted by a pressure regulating valve, which comprises a localized adjustment position between a locking position and a flow position; a bypass duct connected to the adjustment motor and connected to the supply pipe; a spring acting on a regulating piston of the valve device and mounted on the rod to which the pedal of the clutch is connected. The device-valve

  comprises a shut-off valve which constitutes an unlocking valve acting

  the pressure reserve, this stop valve being connected to the con-

  diversion duit. The rod is arranged to abut against the control piston.

  tion, and moves the shutoff valve to its open position.

  According to the invention, the device-valve ensuring the débra-

  yage and the stop valve which connects the pressure reserve to the clutch when the engine is stopped, are mounted in the same box and are coaxial. If the valve device is pushed through a hydraulically activated rod beyond the lock position

  it bears against a bearing piston itself abutting against the

  stop pope. Beyond a point of overpressure, the stop valve is brought into the open position. The energy accumulated in the pressure reserve is therefore available in the adjustment cylinder for disengagement. Being

  as the unlocking of the shut-off valve is effected by coupling

  mechanically, the device has a high degree of operational safety.

  It is particularly advantageous that the suppression caused by the pressure reserve acts on the shut-off valve. The passage to the overpressure point, sensitive during the operation of the clutch pedal, signals the driver that the pressure reserve has been switched on. The use of a seat valve as a shut-off valve also ensures a high degree of

pressure reserve.

  The use of a pressure regulating valve in

  the activation device, moreover, has the advantage of ensuring a

  end of the pressure to be exerted during the disengagement maneuvers, during

normal driving.

  The present invention will be better understood with reference to the

  description of an exemplary embodiment, and the appended drawings in which

  FIG. 1 represents the diagram of the oil circuit of the

  appears from the activation device, and Figure 2 shows a schematic section through the

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  valve device surrounded by a broken line in FIG.

  As shown in FIG. 1, the activation device equipped with an oil supply unit comprises an oil reservoir 1, a filter

  2, a pump 3 and a pressure reserve 4. The pump 3 is connected by means of

  intermediate of a supply line 5 to a valve device 6, constituted by a pressure regulating valve. The valve device 6 comprises a locking position I relative to the return duct 7, a flow position II and a setting position III. The return duct passes through an oil cooler 8 and is connected to the lubrication circuit of the mechanism

  -10 training. Thereafter, the oil is returned to the tank 1.

  A bypass duct 10 of the supply duct 5 is connected to the adjustment motor 11 of a clutch 12. A shutoff valve 13 is mounted coaxially with the valve device 6, and functions as a valve

  Unlocking the pressure reserve 4. Through the pressure relief valve

  13, the pressure reserve 4 can be connected to the bypass duct 10. The bypass duct 10 is also connected to the return duct

  7 via a pressure limiting valve 14.

  As shown in FIG. 2, the valve device 6 can be moved when the clutch pedal 15 is depressed, via the

  cylinder 16 of a probe, a connecting pipe 17 and the cylinder of a die.

  18. A piston 20 housed in the cylinder 18 of the detector exerts a pressure

  on a spring 22 by means of a rod 21. This spring 22 takes

  supported by means of a cup 23 on a regulating piston 25,

  Ble flange 19 of the rod 21 is engaged in a bore of the piston 25. A return spring 26 exerts a pressure on the rod 21. The adjusting piston 26 25 comprises a control edge 27 arranged to allow a cut between the annular groove 5A connected to the supply pipe 5 of the annular groove 7A connected to the return pipe 7. A support piston 28, and a piston 30 of the stop valve, are mounted coaxially with the control piston 25 in the bore 24. The stop valve 13 is constituted by a seat valve having

  a seat edge 31 and a sealing cone 32. The pressurized oil

  3 of the pump 3 through the supply duct 5, acts simultaneously on the front face 33 of the bearing piston 28, and on the face 34 of the piston 30 facing the support piston. When the pressure reserve 4 is full, the

  pressure of this reservoir acts on a front surface 35 of greater

  the piston 30 remains in the position shown

  by the figure. The support piston 28 has a shoulder 37 which. is coming

  puyer against a flat spring 36 ensuring its end of race.

  In Figures 1 and 2, the clutch 12 is closed by the action of a spring and the pressurized oil from the pump 3 can flow to

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  through the valve device 6 in the flow position II to the return line 7 towards the lubrication circuit. Any

  pressure can not be generated in the bypass duct 10 and in the

regulator 11.

  If, when the engine is running and drives the pump 3,

  the driver wants to disengage, he presses the clutch pedal 15 for the

  in the adjustment position III. In doing so, the pressure generated in the cylinder 16 of the probe shifts the piston of the cylinder 18 of the sensor

  upwards so that the tension of the spring 22 is increased by the intermediate

  In this way the section of the fluid discharge port towards the annular groove 7A, defined by the control edge 27 of the regulating piston 25, decreases, the pump must therefore provide

  an upper pressure on the front face 33 of the support piston 28, for main-

  hold the control edge 27 in the open position. As a result, the force generated by the pump and the force exerted by the springs are balanced at

  when the clutch pedal is pressed. The overpressure generated is transmitted

  put through the bypass duct 10, acts on the adjustment motor 11 and

  ensures the opening of the clutch 12.

  When the engine is stopped, that is to say when the pump

  3 is not driven, the disengagement operation is carried out as follows:

  when the clutch pedal 13 is depressed, the regulation piston 25 is brought into the locking position I by the action of the spring 22. The control edge 27, in the absence of a pressure generated by the pump and exerted on the end face 33 of the support piston 28, closes the annular groove 7A connected to the return duct 7. At this moment, the shoulder 37 of the support piston 28 takes

  bearing against the flat spring 36 and simultaneously the front face 33 of the piston

  30 of the stop valve 13 abuts. To open the piston 30, it is necessary to overcome the force exerted by the pressure reserve on the front face 35, and the force of the flat spring 36. This additional force is

  sensitive at the level of the clutch pedal and defines a pressure point.

  To overcome this force, the rod 21 presses through its flange 19 on the regulating piston 25, so that the unlocking pressure

  acts on the piston 30 of the shut-off valve 13 via an actuator

  mechanical coupling. When the piston 30 is effectively pushed back, the

  The regulator 11 is brought into the disengaged position by virtue of the pressure

of the pressure reserve.

  It is also possible to choose the diameter of the piston 30

  in such a way that the pressure generated by the pressure reserve

  on the front face 35, which is sufficient to create the force of release.

  rusting. In this case, the flat spring 36 can be removed.

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Claims (4)

  1. Activation device for controlling the hydraulic opening of a clutch actuated in the closing direction by a spring force, comprising: - an oil supply unit comprising a reservoir 1, a pump 3, a pressure reserve 4 and a stop valve 13 cooperating with   the pressure reserve, this unit being connected to a feed pipe 5;   a valve device 6 mounted between the feed pipe   5 and a return pipe 7, this device having a locking position I and a flow position 11 for the activation of a setting motor 11, characterized in that   the valve device 6 is constituted by a valve   pressure gulatrice, which comprises an adjustment position III located between the locking position I and the flow position II; a bypass branch 10 connected to the adjustment motor 11 and connected to the supply pipe 5; - A spring 22 acting on a regulating piston 25 of the valve device 6 and mounted on the rod 21 which is connected to the pedal 15 of the clutch; - The valve device comprises a stop valve 13 which constitutes an unlocking valve acting on the pressure reserve 4, this stop valve being connected to the bypass duct 10;   the rod 21 is arranged to abut against the control piston   25, and moves the stop valve 13 to its open position.   2. Device according to claim 1, characterized in that the stop valve 13 which constitutes an unlocking valve for the pressure reserve 4, is arranged coaxially with the valve device 6,   and in that a backup piston is mounted between the shut-off valve 13 and the piston regulation tone 25.   3. Device according to any one of the preceding claims   cedeentes, characterized in that the stop valve 13 is conitued by a seat valve.   4. Device according to claim 1, characterized in that the bypass duct 10 connected to the adjustment motor 11, is connected to the   return duct 7 via a pressure limiting valve 37 sion.