DE102015219661A1 - Clutch actuation system - Google Patents

Abstract

The invention relates to a clutch actuation system for at least one clutch (12) of a motor vehicle which can be actuated via a pedal (14), with a master cylinder (16) and a slave cylinder (18) which are interconnected by a fluidic path (20) between the master cylinder (16) and the slave cylinder (18) a pump actuator module (22, 46, 62, 72) for automated or semi-automatic clutch actuation is arranged, wherein the pump actuator module (22, 46, 62, 72) a pump (24) and a Differential pressure relief valve (26), wherein in the fluidic path (20) a valve assembly is arranged for selecting the pump actuator module (22, 46, 62, 72) in an automated or semi-automatic clutch actuation, wherein the differential pressure relief valve (26) with the fluidic path (20) is connected and connected via a return line (28) with a reservoir (30) for providing and / or storage of working fluid en is for the return of additional working fluid in the fluidic path (20). In this way, a clutch actuation system can be simplified.

Description

The invention relates to a clutch actuation system for a motor vehicle for realizing an automated clutch actuation in manual transmissions.

From the German patent application DE 10 2009 014 472 A1 An arrangement for actuating a master cylinder of a hydraulic system for clutch actuation is known, with a rotatably mounted body-mounted pedal, which is connected by means of a transmission device in operative connection with the master cylinder piston, wherein the transmission device comprises a gear transmission. From the German patent application DE 10 2008 059 787 A1 a hydraulic system for motor vehicles is known with a master cylinder and a slave cylinder, which are interconnected by a hydraulic path in which a pump and a servo valve means are arranged so that the effect of an applied to the master cylinder actuating force is increased to the slave cylinder, wherein the hydraulic path, an additional pumping surge having an input and an output and a switching valve device are arranged so that the effect of an applied force applied to the master cylinder actuating force on the slave cylinder is further dependent on demand. From the German patent application DE 10 25 2009 049 246 A1 a clutch pedal force assist device is known, which is connected via a hydraulic path to a master cylinder and a slave cylinder, in which a pump, a check valve device and a servo valve device with a reciprocable valve spool are arranged so that the action of an applied to the master cylinder operating force the slave cylinder is reinforced, wherein on the valve slide, a sealing edge or sealing surface is provided, which is a valve seat with a fixed seat or seat edge on the housing of the servo valve device.

There is therefore a continuing need to simplify a structure of a clutch actuation system. It is therefore an object of the invention to simplify the construction of the clutch actuation system.

The object is achieved according to the invention by a clutch actuation system having the features of claim 1. Preferred embodiments of the invention are specified in the subclaims, which individually or in combination may constitute an aspect of the invention.

The invention relates to a clutch actuation system for at least one operable via a pedal clutch of a motor vehicle, with a master cylinder and a slave cylinder, which are interconnected by a fluidic path, wherein between the master cylinder and the slave cylinder a pump actuator module for automated or semi-automatic clutch actuation is arranged the pump actuator module comprises a pump and a differential pressure relief valve, wherein in the fluidic path a valve arrangement is arranged for selecting the pump actuator module for automated or semi-automatic clutch actuation, wherein the differential pressure relief valve is connected to the fluidic path and a return line with a reservoir for providing and / or storage of working fluid is connected to the return of additional working fluid in the fluidic path.

The pump actuator module can be connected as an expansion pack, as a so-called add-on, to a manual clutch to allow automated actuation of the clutch. The pump of the pump actuator module can be a unidirectional pump or a reversing pump. With the help of the pump actuator module special functions in the operation of a motor vehicle can be realized, for example, a sailing operation of a motor vehicle

The valve arrangement may be arranged in the fluidic path or at a connection between the fluidic path and the pump actuator module, preferably in the vicinity of the slave cylinder. The valve assembly may prevent backflow of the working fluid, for example, a hydraulic oil, a gear oil or engine oil, in a manual operation in the pump actuator module or prevent backflow into the fluidic path in an automatic actuation of the clutch. In particular, with the aid of the valve arrangement, either the fluidic path or the pump actuator module can be connected to the master cylinder and via the master cylinder to the reservoir. For example, the valve assembly may be a directional control valve which can switch via a control unit between the fluidic path for manual actuation of the clutch or the pump actuator module for automatic actuation of the clutch. In particular, a constant working pressure of the working fluid in the fluidic path and / or in the pump actuator module can be realized with the aid of the valve arrangement. For example, the valve arrangement can switch from the fluidic path to the pump actuator module as soon as a certain working pressure and / or in the slave cylinder a certain slave piston travel has been reached. The switching can be done for example by means of a pressure gauge in the slave cylinder. It can, for example, by the pressure gauge Signal are transmitted to the pump for starting the pump, so that thereby the volume flow of the working fluid is diverted via the pump actuator module.

The differential pressure relief valve may be arranged in the fluidic path in the vicinity of the master cylinder in order to be able to return an amount of excess working fluid supplied by the master cylinder into the reservoir. This may be done by connecting the differential pressure relief valve to the fluidic path, and at a working fluid pressure increased by an additional working pressure in the fluidic path may open the differential pressure relief valve to direct excess working fluid back into the reservoir. In addition, by opening the differential pressure relief valve, the pump of the pump actuator module can be stopped, so that when opening the pressure difference pressure relief valve, the clutch actuation system can be switched to the manual actuation mode, the so-called normal mode. The differential pressure relief valve may be an electromagnetically operable differential pressure relief valve or a mechanical differential pressure relief valve. The mechanical differential pressure relief valve may comprise an elastic element to keep the differential pressure relief valve closed. The elastic member may be, for example, a compression spring, a tension spring or a cup spring, and hold the pressure difference pressure relief valve in a closed position at a normal or low working fluid pressure in the fluidic path.

In a manual operation of the clutch, the so-called normal operation, the pedal can be mechanically operated with one foot. As a result, a fluid column of a working fluid, for example a hydraulic oil, gear oil or engine oil, can be transmitted from the master cylinder via the fluidic path to the slave cylinder in order to actuate the clutch. The valve arrangement can be connected in such a way that a return flow of the working fluid into the pump actuator module can be prevented. In a manual operation of the clutch, the differential pressure relief valve can not trigger because the working fluid pressure in the fluidic path can correspond to a normal working pressure and a mechanical differential pressure relief valve in addition a spring force of an elastic element can ensure the firing position of the differential pressure relief valve.

In an automated clutch actuation, such as a sail entry, the pump can be driven. For example, the pump of the pump actuator module can be driven by a drive, in particular an electric motor. This allows the pump to draw working fluid from the reservoir via the master cylinder. The master cylinder may include a sniffer bore to draw working fluid from the reservoir. The pump can deliver the working fluid through the pump actuator module in the direction of the clutch. The resulting flow rate can switch the valve arrangement, so that the fluidic path can be separated from the coupling. The clutch can thereby be actuated by the pump actuator module. The differential pressure relief valve may remain closed because the working fluid pressure in the fluidic path may be smaller than the normal working fluid pressure, and may additionally act in a mechanical differential pressure relief valve, a spring force of an elastic element. Once the maximum actuation travel in the slave cylinder is achieved, the pump actuator module can either circulate the working fluid within the pump actuator module or the pump can be turned off by means of internal or external logic. An external logic may be, for example, a displacement sensor, which may for example be arranged in the slave cylinder and may monitor the actuation path during the automatic operation. When the maximum permissible travel is reached, the displacement sensor can transmit a signal to a control unit or to the drive of the pump, in particular an electric motor, in order to switch off the pump. When the pump is switched off, unwanted closing of the clutch can be detected due to leaks. By briefly switching on the pump then closing the clutch can be prevented. Furthermore, the pump actuator module may include volume receptacles for the working fluid between the pump and the clutch to provide working fluid for the targeted on and off operations to prevent accidental closing of the clutch.

With automated clutch retention, so-called sailing, either the pump in the pump actuator module can be turned off, whereby the working fluid pressure in the clutch actuation system can be nearly constant, or the working fluid can circulate in the pump actuator module. In this case, the pump can continue to operate, but this is done at a much lower pressure level, whereby a required power requirement of the pump drive can be significantly reduced.

In an automated engagement, the so-called sail outlet, in a pump designed as a reversible pump, the direction of rotation the pump are reversed. By reversing the direction of pump rotation, the volume flow of the working fluid can be conveyed back via the pump actuator module from the slave cylinder via the master cylinder into the reservoir. In a pump with a pumping direction, the valve assembly may receive a signal to switch over a control logic and the pump may receive a signal to stop via the control logic so that the valve logic can switch to the fluidic path and the working fluid over the fluidic path of the Slave cylinder can be passed to the master cylinder in the reservoir.

In this way, the robustness of the mechanical / hydraulic logic can be increased and a structure of the clutch actuating system can be simplified.

It is preferred that through the differential pressure relief valve via lines or sensors in the fluidic path a working fluid pressure to the master cylinder and a working fluid pressure is monitored in front of the slave cylinder, wherein at a working fluid pressure after the master cylinder greater than the working fluid pressure in front of the slave cylinder via the differential pressure Pressure limiting valve, the additional working fluid is traceable into the reservoir. In this way, the working fluid pressure in the fluidic path can be monitored by the differential pressure relief valve. For example, with manual override of the automated clutch actuation during an automated clutch actuation by the driver, the pedal may be manually actuated. This will stop the pump immediately. This can be done for example with the help of an existing pedal switch. Ideally, the sniffer bore can be closed by the foot control. This has the consequence that at the latest in the further pedal operation, the working fluid pressure ratios can change the differential pressure-relief valve. In particular, may be greater than the working fluid pressure in front of the slave cylinder by the pedal actuation of the working fluid pressure after the master cylinder. As a result, the differential pressure-relief valve can open and the additionally supplied via the foot actuator working fluid can be returned to the reservoir via the differential pressure relief valve and the additional return line. Once the pressure conditions are equalized, the system is in normal operation and the driver can continue to open or close the clutch. The initial force on the pedal can be dependent on the clutch position already reached by the pump actuator module. The differential pressure relief valve can either directly measure the working fluid pressure after the master cylinder and before the slave cylinder either via lines or pressure sensors can transmit the respective working fluid pressure to the differential pressure relief valve.

Preferably, the valve assembly is an OR valve or a check valve. In this way, a control for the valve assembly can be saved. Rather, by the design of the volume flow either via the fluidic path or via the pump line, a switching of the valve arrangement allows and a backflow of the working fluid can be prevented in the unused part of the clutch actuation system. In particular, in one embodiment as an OR valve, the OR valve, a resilient element, such as a compression spring include, so that the OR valve is set in a basic position, for example in the position of manual operation, and in the normal position, for example a Flow rate of the flow in the fluidic route allows. By activating the pump and passing the volume flow through the pump actuator module, the OR valve can then be switched, so that due to the volume flow, the barrier, for example a ball, compresses the elastic element to guide the volume flow of the working fluid through the pump actuator module and to separate the fluidic route. In a check valve, such as a ball check valve, the check valve may include a passage having a restriction which may be closed by a ball. The ball can be pressed by gravity or by a spring on the constriction, whereby the passage is closed. The medium can not flow through. Such valves are generally hermetically sealed in the blocked direction. The check valve can be arranged such that the working fluid from the master cylinder can flow in the direction of the slave cylinder and the return flow is prevented in the reverse direction. The coupling must be closed by a non-return valve with the aid of the pump. When using a check valve, however, an active stall protection for the drive motor is automatically integrated.

In a preferred embodiment, the pump actuator module further comprises a pump line, a circulation valve, a bypass line connected to the pump line with a bypass valve and a recirculation line connected between the circulation valve and the pump line, wherein a circulation module is arranged in the pump line between the circulation valve and the fluidic line, wherein a working fluid pressure before the circulation module and a working fluid pressure after the circulation module is traceable to the circulation valve, and arranged in the recirculation line, a recirculation module is. In this way, the pump actuator module can more easily coordinate semi-automated or automated clutch actuation, semi-automated or automated clutch hold, and semi-automated or automated engagement. In this case, the pump line can connect the pump with the fluidic route. In particular, the pump line can be arranged such that it contacts the fluidic path to the master cylinder and before the slave cylinder, wherein the differential pressure relief valve is not in contact with the pump line. About the pump line, the pump can direct working fluid from the master cylinder to the slave cylinder, further, the working fluid can be passed from the slave cylinder to the master cylinder in a designed as a reversing pump pump. The circulation valve may be a directional control valve or an OR valve and direct the working fluid after the pump via the pump line in the direction of the fluidic path in front of the slave cylinder or the working fluid in the recirculation line. After the circulation valve may be in the direction of the slave cylinder in the pump line, a circulation module to monitor the working fluid pressure in the pump line. In this case, the circulation valve via lines or sensors monitor a working fluid pressure upstream of the circulation module and a working fluid pressure downstream of the circulation module. The circulation module can furthermore be designed in such a way that, for example in the case of automated engagement, it can prevent a backflow of the working fluid into the circulation valve, so that the working fluid can be conducted via the bypass line from the slave cylinder to the master cylinder. That arranged in the bypass line bypass valve may be, for example, a directional control valve or a check. In the recirculation line, a recirculation module can be arranged, which can report a working fluid pressure to the bypass valve. The working fluid pressure can be transmitted via a line directly or via a sensor to the bypass valve. Furthermore, the bypass valve may detect a working fluid pressure of the working fluid in the bypass passage in the direction from the slave cylinder to the bypass valve. The circulation valve and the bypass valve may be mechanically configured and held in an initial position via an elastic element, for example a compression spring. Below a working fluid pressure, the circulation valve and the bypass valve can be switched by means of the respective elastic elements in their normal position. Furthermore, the circulation valve or the bypass valve may be designed magnetically or electromagnetically.

In an automated clutch actuation, the so-called sail entry, the pump can suck on the master cylinder and a sniffer bore in the master cylinder working fluid from the reservoir and promote via the pump line in the direction of the circulation valve. In the basic position of the circulation valve, the working fluid can pass through the circulation valve. In the circulation valve, a pressure drop can occur. This pressure drop can be returned to the circulation valve. By a spring and surface design of the circulation valve, the circulation valve can remain in the home position, so that the clutch can be actuated. When the maximum actuating travel in the slave cylinder is reached, the volume flow of the working fluid in the circulation module drops to zero. Thereby, a pressure equality between the working fluid pressure before the circulation module and the working fluid pressure after the circulation module prevail. As a result, the circulation valve can switch to the circulation mode by the area design and the spring design in the circulation valve. In this case, the still supported by the pump volume flow can be passed through the circulation valve in the recirculation line and returned to the suction side of the pump. Depending on the design of the circulation valve, the changeover to the circulation mode can also take place continuously when a defined pressure difference is undershot. The pump pressure in the circulation mode can be significantly lower than during the actuation of the clutch. However, the pump pressure may be higher than the ambient pressure to ensure a switching function of the bypass valve can. As a typical pump pressure for actuating the clutch, a pressure range between greater than 10 bar to less than 100 bar, preferably greater than or equal to 15 bar to less than or equal to 60 bar, in particular greater than or equal to 20 bar to less than or equal to 50 bar, while being more typical Circulation pressure range, a pressure range between greater than 0 bar to less than or equal to 15 bar, preferably greater than or equal to 0.5 bar to less than or equal to 12 bar, preferably greater than or equal to 1 bar to less than or equal to 10 bar, can be called.

In an automated holding of the clutch, the so-called sailing, the pump can continue to operate in the circulation mode described above. This is done in a lower pressure range, so that the power requirement of the drive of the pump can be reduced.

In an automated clutch engagement, the so-called sail outlet, the direction of rotation of the pump can be reversed in a reversing pump. By reversing the direction of rotation of the flow of the working fluid can be interrupted in the recirculation line. In this way, the working fluid pressure signal from the recirculation line to the bypass valve can be omitted. Furthermore, the working fluid pressure can be reduced by the working fluid returned by the slave cylinder increase the bypass line, so that the bypass valve from a basic position lock the bypass line can be switched to an open position to direct the working fluid from the slave cylinder via the master cylinder in the reservoir can.

It is preferred that the circulation valve is a directional control valve. In particular, the directional control valve may comprise two switching positions. A first switching position for directing the working fluid to the slave cylinder and a second switching position for directing the working fluid into the recirculation line. The directional control valve can be held by means of an elastic element in the first switching position.

Preferably, the bypass valve is a directional control valve or a check valve. In this way it can be ensured that the bypass valve can only be actuated in the event of automated engagement. In a bypass valve designed as a bypass valve, the bypass valve may comprise two switching positions. A first switching position for blocking the bypass line and a second switching position for the passage of the working fluid through the bypass valve. The bypass valve may include a resilient member to hold or return the bypass valve in the first switching position.

In a preferred embodiment, the circulation module comprises a throttle, a metering or a valve switch signal generator. In this way, a working fluid pressure can be influenced by the circulation module, in particular reduced or increased. Furthermore, with the aid of a circulation module designed in this way, a backflow of the working fluid can be prevented in an automated engagement, so that no working fluid can be conducted to the master cylinder via the circulation valve.

It is preferred that the recirculation module comprises at least one check valve, a throttle, a metering orifice and / or a valve switch signal generator. In this way, a working fluid pressure in the recirculation line can be influenced and detected.

Preferably, a working fluid pressure in the recirculation line to the bypass valve is transferable. In this way, the bypass valve can be transferred to the second switching position, if no working fluid pressure can be measured in the recirculation line.

The invention further relates to a method for actuating a clutch actuation system for at least one clutch of a motor vehicle, in particular a clutch actuation system, which may be formed or developed as above, wherein in an automated clutch actuation by manual operation of the pedal, the automated clutch actuation is overruled, the by the operation of the pedal supplied working fluid in the fluidic path generates a pressure increase in the fluidic path, wherein the pressure increase, the differential pressure relief valve opens and the supplied working fluid from the fluidic path via the differential pressure relief valve is fed back into the connected reservoir, and with a compensation of the pressure conditions in the fluidic path, the clutch actuation system in a normal operation, in particular in a manual operation operation, overf is led.

With the aid of a method which is used in a clutch actuation system, in particular in a clutch actuation system which may be designed or developed as described above, a clutch actuation system can be provided which can have increased robustness of the mechanical and / or hydraulic logic and simpler can be constructed.

The invention will now be described by way of example with reference to the accompanying drawings with reference to preferred embodiments, wherein the features shown below, both individually and in combination may represent an aspect of the invention. Show it:

1 a schematic view of a first embodiment of a clutch actuation system;

2 a schematic view of a second embodiment of a clutch actuation system;

3 a schematic view of a third embodiment of a clutch actuation system;

4 a schematic view of a fourth embodiment of a clutch actuation system

5 a schematic view of a fifth embodiment of a clutch actuation system in an automatic clutch operation;

6 a schematic view of the fifth embodiment of the clutch actuation system in an automated engagement;

7 a schematic view of a sixth embodiment of a clutch actuation system;

8th a pressure curve of the pressure waveforms of the slave cylinder and the differential pressure relief valve over the path of the slave cylinder; and

9 a diagram of a nominal valve characteristic of a circulation valve.

In the following description of the figures, the same reference numerals are used for the same components or terms.

In 1 is a clutch actuation system 10 shown. The clutch actuation system 10 includes a clutch 12 which has a pedal 14 with the help of a master cylinder 16 and a slave cylinder 18 over a fluidic route 20 is pressed. The master cylinder 16 is with the pedal 14 connected to the pedal 14 applied pressure over the fluidic path 20 to the slave cylinder 18 to transfer to the clutch 12 to press. The slave cylinder 18 is with the clutch 12 connected. Furthermore, the clutch actuation system comprises a pump actuator module 22 which acts as an add-on module between the master cylinder 16 and the slave cylinder 18 is arranged. The pump actuator module 22 includes a pump 24 , In this embodiment, a reversing pump, which is driven by an electric motor, a pump line 34 and a differential pressure relief valve 26 , Both the master cylinder 16 , as well as the differential pressure relief valve 26 are with a reservoir 30 for the working medium, such as a hydraulic oil, connected. The differential pressure relief valve 26 is via a return line 28 with the reservoir 30 connected. Furthermore, the differential pressure-relief valve 26 directly with the fluidic route 20 connected. The dashed lines on the differential pressure relief valve 26 indicate that the differential pressure relief valve 26 Information about the working fluid pressure of the fluidic path 20 after the master cylinder 16 and information about the working fluid pressure of the fluidic path 20 in front of the slave cylinder 20 receives.

In a normal operation of the clutch actuation system 10 becomes the pedal 14 actuated. This will create a fluid column from the master cylinder 16 over the fluidic route 20 in the slave cylinder 18 shifted, causing the clutch 12 through the slave cylinder 18 is pressed. At the fluidic route 20 is located in front of the slave cylinder 18 an OR valve 32 in order to actuate the clutch 12 between the fluidic route 20 or the pump line 34 of the pump actuator module 22 to switch. In normal operation, the ball of the OR valve is located 32 in the pictorial lower position and thereby gives the direct path between the master cylinder 16 and the slave cylinder 18 free. At the same time, the OR valve prevents 32 a fluid reflux in the direction of the pump line 34 , The OR valve 32 can be kept in this normal operating position with a spring, not shown. The differential pressure relief valve 26 does not trigger in normal operation, since the pressure of the working fluid after the master cylinder 16 about the pressure of the working fluid in front of the slave cylinder 18 and additionally a spring force corresponds to the firing position of the differential pressure relief valve 26 ensures.

In an automated clutch operation, the so-called sail entry, the electric motor drives the pumps 24 at. This sucks the pump 24 over the master cylinder 16 Working fluid from the reservoir 30 at. The master cylinder 16 it has an opening, not shown, a so-called sniffer bore, which can be closed and via which working fluid from the reservoir 30 in the master cylinder 16 can flow in. The pump 24 promotes the working fluid through the pump line 34 to the slave cylinder 18 , The flow rate switches the OR valve 32 in the position shown, so that the clutch 12 is pressed. The differential pressure relief valve 26 remains in the closed position, as the pressure after the master cylinder 16 less than the pressure in front of the slave cylinder 18 is and in addition the spring force on the differential pressure relief valve 26 acts. Once the maximum actuation of the slave cylinder 18 is reached, the pump 24 off. A monitoring of the actuating travel of the slave cylinder 18 takes place via an external monitoring logic, not shown, which both with the slave cylinder 18 as well as with the electric motor of the pump 24 connected is.

By switching off the pump 24 the pressure of the working fluid in the pump line remains 34 constant, so that the clutch is held automatically, this is also called sailing.

When automated engagement, the so-called sail outlet, the direction of rotation of the pump 24 vice versa. Via the pump line 34 becomes the fluid column from the slave cylinder 18 over the master cylinder 16 promoted back to the reservoir.

Is the pedal during an automated operation by the driver 14 manually operated, the electric motor of the pump immediately becomes 24 stopped. Ideally, the sniffer bore will be in the master cylinder 16 through the foot operation locked. This has the consequence that at the latest in the further pedal actuation, the pressure conditions at the differential pressure-relief valve 26 change as the pressure after the master cylinder 16 greater than the pressure in front of the slave cylinder 18 becomes. The additionally supplied via the foot operation working fluid can via the differential pressure relief valve 26 and about the return 28 into the reservoir 30 to be led back. Once the pressure conditions are equalized, the system is in normal operation and the driver can continue to open or close the clutch.

In 2 is a second embodiment of a clutch actuation system 36 shown. In contrast to the clutch actuation system 10 of the 1 has the coupling system 36 of the 2 a pressure gauge 38 on the slave cylinder 18 on. With the help of the pressure gauge 38 can the actuation path in the slave cylinder 18 be measured in order to stop the pump in an automated operation of the clutch in a timely manner. About the displacement sensor 38 , for example, in the slave cylinder 18 can be arranged, during the automated operation of the actuating path in the slave cylinder 18 supervised. When reaching the maximum permissible travel in the slave cylinder 18 will send a signal to the motor of the pump 24 transmitted to the pump 24 off. In the off state due to leakage, the unwanted closing of the clutch 12 recognized, the pump can 24 be switched on briefly. For these targeted on and off operations are not shown volume recordings in the pump line 34 between pump 24 and clutch 12 quite helpful.

3 shows a third embodiment of a clutch actuation system 40 , In the clutch actuation system 40 the or-valve will pass through a check valve 42 in the fluidic route 20 replaced. In such a clutch actuation system 40 must be the closing of the coupling by the pump 24 get supported. Advantageous in the clutch actuation system 40 However, that is automatically integrated a stalling protection for the drive motor, not shown.

In 4 is a fourth embodiment of a clutch actuation system 44 shown. The clutch actuation system 44 points in its pump actuator module 46 in the pump line 34 a circulation valve 56 and a bypass valve 54 on. The circulation valve 56 is a directional valve with two switch positions and the bypass valve 54 is a check valve. The bypass valve 54 is via a bypass line 48 with the pump line 34 connected. Between the circulation valve 56 and the OR valve 32 is an orifice plate 58 arranged. The circulation valve 56 receives information about the pressure of the working fluid in front of the diaphragm 58 and after the orifice plate 58 , Furthermore, the circulation valve with a recirculation line 50 connected. In the recirculation line 50 is a check valve 52 arranged. The first switching position of the circulation valve connects the pump 24 with the clutch 12 , In the second switching position, the pump 24 with the recirculation line 50 connected.

The normal operation of the clutch actuation system 44 corresponds to the above-described normal operation of the clutch actuating system 10 of the 1 ,

In an automated clutch operation, the so-called sail entry, the electric motor drives the pump 24 at. The pump 24 sucks over the master cylinder 16 and the open unillustrated sniffer bore working fluid from the reservoir 30 and pumps the working fluid through the pump line 34 in the direction of the circulation valve 56 , In the initial position, the circulation valve 56 the illustrated first switching position, so that the working fluid through the circulation valve 56 can flow. At the measuring aperture 58 creates a pressure drop, allowing the pressure in front of the metering orifice 58 greater than the pressure after the orifice is. This pressure drop is sent to the circulation valve 56 recycled. Due to the spring and surface design of the circulation valve 58 this remains in the first switching position. The volume flow of the working fluid now switches the OR valve 32 around. The clutch is actuated. The differential pressure relief valve remains 26 safely closed because the pressure after the master cylinder 16 less than the pressure in front of the slave cylinder 18 is and in addition the spring force on the differential pressure relief valve 26 acts. Once the maximum actuation travel in the slave cylinder 18 is reached, the volume flow of the working fluid above the metering orifice decreases 58 to zero. There is thus equal pressure in front of the metering orifice 58 and after the orifice plate 58 , Due to the surface and spring design in the circulation valve 56 takes place for a changeover to the second switching position, the switching position "circulation". The one from the pump 24 Still funded flow is now via the recirculation line 50 the suction side of the pump 24 recycled. Depending on the design of the recirculation valve 56 can the switching to the circulation position from the falling below a defined pressure difference also occur continuously.

When automated holding the clutch 12 , the so-called sailing, becomes the pump 24 in the last described state, simply continue to operate.

When automated engagement, the so-called sail exit, the direction of rotation of the pump 24 be reversed. About the bypass valve 54 becomes the fluid column from the slave cylinder 18 over the master cylinder 16 into the reservoir 30 promoted back. For this to be possible without interference, the check valve closes 52 in the recirculation line 50 ,

With a manual override of the Automated Clutch Actuation, the pedal becomes 14 manually operated by the driver. This immediately becomes the electric motor of the pump 24 stopped. Ideally, the sniffer bore is already closed by the foot control. This has the consequence that at the latest in the further pedal actuation, the pressure conditions at the differential pressure-relief valve 26 to change. The pressure after the master cylinder 16 is greater than the pressure in front of the slave cylinder 18 , The additionally supplied via the foot control working fluid is via the differential pressure relief valve 26 and the additional return 28 into the reservoir 30 recycled. Once the pressure conditions are equalized, the clutch actuation system is located 44 in normal operation and the driver can use the clutch 12 continue to open or close further.

5 shows a fifth embodiment of a clutch actuation system 60 , The arrows in 5 indicate that the clutch actuation system 60 in the automated clutch operation, the so-called sail entry, is operated. The clutch actuation system 60 has a pump actuator module 62 on. The pump actuator module 62 includes in the recirculation line 50 a valve switch signal generator 68 for the bypass valve 67 on. The valve switch signal generator 68 is with the bypass valve 67 coupled. Furthermore, the bypass valve 67 with the bypass line 48 coupled. The bypass valve 67 is a directional control valve with two switch positions. In the first switching position is the bypass line 48 interrupted. In a second switching position, the bypass line 48 closed. The pump actuator module 62 points instead of the orifice plate 58 of the 4 a valve switch signal generator 68 on. The valve switch signal generator 68 is with the circulation valve 57 connected.

When in the 5 the automatic motor drives the pump 24 at. The pump 24 sucks over the master cylinder 16 and the unillustrated open sniffer bore working fluid from the reservoir 30 and promotes this in the direction of the circulation valve 57 , In the first switching position of the circulation valve 57 the working fluid can be the circulation valve 57 happen. In the valve switch signal generator 68 there is a pressure drop. This pressure drop is sent to the circulation valve 57 recycled. Due to the spring and surface design of the circulation valve 57 this remains in the first switching position. The volume flow now switches the OR valve 32 around. The coupling 12 is pressed. The differential pressure relief valve 26 remains securely closed because the pressure after the master cylinder 16 less than the pressure in front of the slave cylinder 16 is and in addition the spring force on the differential pressure relief valve 26 acts. Once the maximum actuation travel in the slave cylinder 18 is reached, the volume flow in the valve switch signal generator decreases 68 to zero. There is pressure equality. This means that the pressure in front of the valve switch signal generator 68 equal to the pressure after the valve switch signal generator 68 is. Due to the surface and spring design in the circulation valve 57 this is the circulation valve in the second switching position, the circulation position, switched. The one from the pump 24 Still funded flow is now via the recirculation line 50 the suction side of the pump 24 recycled. Depending on the design of the circulation valve 67 the switching to the circulation position from the falling below a defined pressure difference can also be continuous. The pump pressure in the circulation case is significantly lower than during the operation of the clutch, however, higher than the air pressure to the switching function of the bypass valve 67 to be able to ensure. For example, the pressure during actuation is 20 to 50 bar, and a typical circulation pressure range is a pressure range between 1 and 10 bar.

In the 6 is the automated engagement, the so-called sail exit, of the clutch actuation system 60 shown. This is illustrated by the arrows. To initiate the coupling process, the direction of rotation of the pump must be 24 be reversed. By reversing the direction of pump rotation, the volume flow through the circulation line 50 interrupted. The additional pressure signal at the bypass valve 67 eliminated. The on the bypass valve 67 Returned clutch pressure dominates and switches the bypass valve 67 around. About the bypass valve 67 becomes the fluid column from the slave cylinder 18 over the master cylinder 16 into the reservoir 30 promoted back.

In 7 is a sixth embodiment of a clutch actuation system 70 shown. The pump actuator module 72 the clutch actuation system 70 points in the recirculation line 50 a check valve 52 and an orifice plate 74 on. The between the check valve 52 and the metering orifice 74 determined pressure is applied to the bypass valve 66 transfer. Furthermore, the pump actuator module 72 instead of between the circulation valve 56 and the OR valve 32 an orifice plate 58 on. The pressure in front of the metering orifice 58 and the pressure after the orifice plate 58 be to the circulation valve 56 transmitted.

In 8th are the pressure profiles of the pressure p of the slave cylinder and the differential pressure Pressure relief valve activation via slave cylinder stroke z is shown. The x-axis represents the slave cylinder travel z and the y-axis the pressure p. The slave cylinder travel z can be measured, for example, in millimeters or centimeters and the pressure p in bar. The pressure curves are shown symbolically. The solid line b shows the symbolic pressure curve in the slave cylinder on the slave cylinder. The dashed line a quantitatively shows the differential pressure relief valve tripping pressure when the driver overrides the automated clutch operation with the pedal.

9 shows a qualitative the nominal valve characteristic of the circulation valve. On the y-axis, the ratio of the volume flow of the circulation line and the flow rate of the pump is shown and on the x-axis, the pressure ratio of the pressure before the valve switch or orifice and the pressure after the valve switch or orifice plate is shown.

LIST OF REFERENCE NUMBERS

10

 Clutch actuation system

12

 clutch

14

 pedal

16

 Master cylinder

18

 slave cylinder

20

 fluidic route

22

 Pumpenaktormodul

24

 pump

26

 Differential pressure relief valve

28

 return

30

 reservoir

32

 OR-valve

34

 pump line

36

 Clutch actuation system

38

 pressure gauge

40

 Clutch actuation system

42

 check valve

44

 Clutch actuation system

46

 Pumpenaktormodul

48

 bypass line

50

 recirculation

52

 check valve

54

 bypass valve

56

 circulation valve

57

 circulation valve

58

 orifice

60

 Clutch actuation system

62

 Pumpenaktormodul

64

 Valve switching signal generator

66

 bypass valve

67

 bypass valve

68

 Valve switching signal generator

70

 Clutch actuation system

72

 Pumpenaktormodul

74

 orifice

p

 print

z

 Way slave cylinder

p _z

 pressure ratio

Q _R / Q _P

 Volume flow ratio

a

 pressure curve

b

 pressure curve

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009014472 A1 [0002]
• DE 102008059787 A1 [0002]
• DE 10252009049246 A1 [0002]

Claims (10)

Clutch actuation system for at least one pedal ( 14 ) actuatable coupling ( 12 ) of a motor vehicle, with a master cylinder ( 16 ) and a slave cylinder ( 18 ) passing through a fluidic path ( 20 ), wherein between the master cylinder ( 16 ) and the slave cylinder ( 18 ) a pump actuator module ( 22 . 46 . 62 . 72 ) is arranged for automated or semi-automatic clutch actuation, wherein the pump actuator module ( 22 . 46 . 62 . 72 ) a pump ( 24 ) and a differential pressure relief valve ( 26 ), wherein in the fluidic path ( 20 ) a valve arrangement is arranged for selecting the pump actuator module ( 22 . 46 . 62 . 72 ) in an automated or semi-automatic clutch actuation, the differential pressure relief valve ( 26 ) with the fluidic path ( 20 ) and via a return line ( 28 ) with a reservoir ( 30 ) for the supply and / or storage of working fluid is connected to the return of additional working fluid in the fluidic path ( 20 ). Clutch actuation system according to claim 1, characterized in that by the differential pressure-relief valve ( 26 ) via lines or sensors in the fluidic path ( 20 ) a working fluid pressure downstream of the master cylinder ( 16 ) and a working fluid pressure in front of the slave cylinder ( 18 ) is monitored, wherein at a working fluid pressure after the master cylinder ( 16 ) greater than the working fluid pressure in front of the slave cylinder ( 18 ) via the differential pressure relief valve ( 16 ) the additional working fluid into the reservoir ( 30 ) is traceable. Clutch actuation system according to claim 1 or 2, characterized in that the valve arrangement comprises an OR valve ( 32 ) or a check valve ( 42 ). Clutch actuation system according to one of claims 1 to 3, characterized in that the pump actuator module ( 22 . 46 . 62 . 72 ) a pump line ( 34 ), a circulation valve ( 56 . 57 ), one on the pump line ( 34 ) connected bypass line ( 48 ) with a bypass valve ( 54 . 66 . 67 ) and one between the circulation valve ( 56 . 57 ) and the pump line ( 34 ) connected recirculation line ( 50 ), wherein in the pump line ( 34 ) between the circulation valve ( 56 . 57 ) and the fluidic line ( 20 ) a circulation module is arranged, wherein a working fluid pressure before the circulation module and a working fluid pressure after the circulation module to the circulation valve ( 56 . 57 ) is traceable, and in the recirculation line ( 50 ) A recirculation module is arranged. Clutch actuation system according to claim 4, characterized in that the circulation valve ( 56 . 57 ) is a directional control valve. Clutch actuation system according to claim 4 or 5, characterized in that the bypass valve ( 54 . 66 . 67 ) is a directional control valve or a check valve. Clutch actuation system according to one of claims 4 to 6, characterized in that the circulation module a throttle, a metering orifice ( 58 ) or a valve switch signal generator ( 68 ). Coupling system according to one of claims 4 to 7, characterized in that the recirculation module at least one check valve ( 52 ), a throttle, an orifice plate ( 74 ) and / or a valve switch signal generator ( 64 ). Clutch actuating system according to one of claims 4 to 8, characterized in that a working fluid pressure in the recirculation line ( 50 ) to the bypass valve ( 66 . 67 ) is transferable. Method for actuating a clutch actuation system ( 10 . 36 . 40 . 44 . 60 . 70 ) for at least one clutch ( 12 ) of a motor vehicle, in particular a clutch actuation system according to one of claims 1 to 9, characterized in that in an automated clutch actuation by a manual actuation of the pedal ( 14 ) the automated clutch actuation is overruled, which by pressing the pedal ( 14 ) supplied working fluid in the fluidic path ( 20 ) a pressure increase in the fluidic path ( 20 ), wherein the pressure increase, the differential pressure-relief valve ( 26 ) opens and the supplied working fluid from the fluidic path via the differential pressure relief valve ( 26 ) into the connected reservoir ( 30 ) and when balancing the pressure conditions in the fluidic path ( 20 ) the clutch actuation system ( 10 . 36 . 40 . 44 . 60 . 70 ) is converted into a normal operation, in particular in a manual operation operation.

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