DE19849488C2 - Hydraulic actuating device for actuating a friction clutch and an automated gearbox - Google Patents

Description

The invention relates to a hydraulic actuator for Actuation of a friction clutch and an automated gearbox A vehicle, comprising: a hydraulic source for providing Hydraulic pressure medium; one of a friction clutch to be operated assigned first hydraulic actuating cylinder arrangement; one of a shift mechanism nik a second hydraulic to be actuated gearbox assigned Actuator assembly; a comprising at least one proportional valve first hydraulic valve arrangement, via which to actuate at least the Friction clutch (possibly also for actuating the manual transmission) at least the first hydraulic actuating cylinder arrangement (if applicable also the second hydraulic actuating cylinder arrangement) hydraulic pressure medium can be fed from the hydraulic source; and at least a proportional valve comprehensive second hydraulic valve assembly, via which for actuation at least the manual transmission at least the second hydraulic Actuator arrangement hydraulic pressure medium from the hydraulic source is feedable.

Such an actuator is for example from DE 297 14 652 U1 known. In the known actuator is the first Hydraulic valve arrangement of a 3/3-way proportional valve and one this downstream 3/2-way valve formed. Depending on the Switch position of the 3/2-way valve is either that of an actuator cylinder formed first hydraulic actuating cylinder arrangement or one Lane selection cylinder of the second hydraulic actuating cylinder arrangement hydraulics pressure medium can be supplied from the hydraulic source via the proportional valve.  

The second hydraulic valve arrangement comprises a further proportional valve, via a double acting actuator serving as a switching cylinder cylinder of the second hydraulic actuating cylinder arrangement hydraulic pressure dium can be supplied with controllable / adjustable pressure, namely via a 4/3-way valve, which is a piston arrangement in a first switching state of the actuating cylinder in the sense of a movement of the piston arrangement in a hydraulic pressure medium applied in the first actuating direction, in a second Switching state of the piston arrangement in the sense of a movement of the pistons arrangement in a second, opposite to the first adjustment direction Hydraulic pressure medium applied and in a third switching state Actuating cylinder both in the direction of the proportional valve and in the direction shut off to an expansion tank. Both proportional valves, that is the hydraulic slave cylinder for clutch actuation and the Proportional valve associated with the selection cylinder of the first hydraulic valve arrangement voltage as well as that assigned to the double-acting actuating cylinder Proportional valve, are connected directly to the hydraulic source, so that Both proportional valves are constantly supplied with hydraulic pressure medium. The hydraulic source comprises a drivable by an electric motor Hydraulic pump and an accumulator.

A further hydraulic actuating device of the type mentioned at the outset is known from DE 196 37 001 A1 in several design variants. According to an embodiment variant ( Fig. 13 of the published specification), the first hydraulic valve arrangement is formed by a proportional valve and two switching valves, the proportional valve designed as a pressure control valve being connected directly to a hydraulic slave cylinder of the first hydraulic actuating cylinder arrangement and via the two switching valves to a differential cylinder serving as a selection cylinder the second hydraulic actuating cylinder arrangement is connected. The second hydraulic valve arrangement is formed by a proportional valve designed as a pressure control valve and a switching valve, which serve to control a differential cylinder of the second hydraulic actuating cylinder arrangement serving as a switching cylinder. Both proportional valves are connected directly to the hydraulic source and are accordingly continuously supplied with hydraulic pressure medium.

Another hydraulic actuator for actuating a Friction clutch and an automated gearbox is out of the WO 96/23671 known. Furthermore, DE 44 39 447 C1 discloses one hydraulic actuator for a friction clutch in Ver binding with a pneumatically operated automated manual transmission. The actuator has a clutch actuator acting hydropneumatic booster. The activity direction offers an emergency dome function.

In the hydraulic actuation devices according to DE 297 14 652 U1 and DE 196 37 001 A1 is a relatively large one due to the hydraulic source Leakage compensation must be carried out, since there is always at least two proportional valves, the design causes a relatively large leakage loss have, by hydraulic pressure supplied by the hydraulic source dium are under pressure.

As a rule, the hydraulic system becomes in such actuators run source so that a hydraulic pump is provided to under Pressurized hydraulic pressure medium in a pressure accumulator to save. Usually driven by an electric motor Hydraulic pump is only switched on if necessary, if the from Hydraulic pressure output hydraulic pressure below a threshold drops in order to close the pressure reservoir with hydraulic pressure medium again fill until the pressure in the accumulator exceeds a second threshold value has risen. Due to the relatively large leakage loss of the Proportional valves also constantly drain the pressure accumulator then instead of when the clutch and the manual transmission are not actuated at all  become. This results in a relatively high load on the hydraulics pump driving electric motor.

Such an electric motor has a temperature-dependent maximum on switching duration. If this is exceeded, the electric motor can be caused by a Overheating can be damaged. Also the absolute lifespan of the Motor limits, the lifespan of the frequency and duration of the Engine operation depends. Due to the leakage compensation, the Electric motor be switched on more often and possibly longer than if such leakage compensation was not or only to a lesser extent would be necessary. The electric motor is therefore used accordingly for more frequent applications Switch on and have to design longer duty cycles, which means result in correspondingly high procurement costs for the engine. Taking such an interpretation does not exist, one will be reduced accordingly Have to put up with the life of the electric motor.

A valve-related leakage loss also plays an important role if in a generic hydraulic actuator Emergency actuation function is enabled or provided. For example it may be that due to damage to the transmission or second hydraulic actuating cylinder arrangement or associated therewith Components of the actuator or the motor vehicle engaged gear of the manual transmission can no longer be removed can. In this case, it is desirable that the clutch be permanent can be disengaged to tow the vehicle enable. To do this, the first hydraulic actuating cylinder arrangement would have to a (comparatively long) period that allows towing be kept under hydraulic pressure if - as is usually the case - the first hydraulic actuating cylinder arrangement for disengaging under hydraulics pressure is set. Such an emergency function is in the known actuators equipment according to DE 196 37 001 A1 and DE 297 14 652 U1 probably not fundamentally excluded without this in the writings  details are included. Should such an emergency function with these Known actuators can be realized, but with a relatively high leakage loss from which the friction clutch in one disengaged clutch holding cylinder counted be because in the case of DE 297 14 652 U1 the first hydraulic valve arrangement tion, especially the 3/2-way valve, due to the design leakage loss should not be negligible. In the case of out of DE 196 37 001 A1 known actuator would have the Clutch actuating cylinder connecting to the hydraulic source Proportional valve are kept in the open position, the design-related, relatively high leakage loss of this valve, which is was addressed, must be constantly compensated by the hydraulic source. The leakage losses from the clutch actuating cylinder cause that the emergency function can only be maintained for a short period of time can or that repeatedly to maintain the emergency function again Hydraulic medium are supplied to the clutch actuating cylinder got to. The latter assumes that the actuator including the hydraulic source is / remains functional and is kept in operation.

In contrast, it is an object of the present invention to Provide actuating device of the type mentioned, in which at least a leakage loss to be compensated for by the hydraulic source is reduced.

To achieve this object, according to a first aspect of the invention suggested that the hydraulic actuator be a switching valve in a hydraulic connection between the second hydraulic valve arrangement voltage and the hydraulic source to interrupt this hydraulic connection in a first switching state and to release this hydraulic ver has binding in a second switching state, the switching valve depending on one by means of the first hydraulic valve arrangement adjustable hydraulic pressure between the first and the second  Switching state is switchable. The switching valve makes it possible to second hydraulic valve assembly only under pressure Hydraulic fluid supply when this hydraulic valve assembly is controlled to at least one associated hydraulic Stellzylin the arrangement, in particular the second hydraulic actuating cylinder arrangement, to be supplied with hydraulic pressure medium. For example, the switching valve to be a hydraulically controllable switching valve, which is a hydraulic Has control connection, which on one of the first hydraulic valve arrangement to the first hydraulic actuating cylinder arrangement leading hydraulic actuator binding is connected. The switching valve can last so long in the first The switching status remains, like the hydraulic pressure in this hydraulic connection does not exceed a first switching threshold. Exceeds this Hydraulic pressure the first switching threshold, the switching valve switches to second switching state, so that from now on (until switching back to the first switching state due to falling short of a second switching threshold) the second hydraulic valve assembly with the pressurized Hydraulic pressure medium is supplied from the hydraulic source. The back can switch from the second switching state to the first switching state by a spring arrangement of the switching valve. The switching threshold can, for example, at about 10% of the maximum hydraulic pressure of the first Hydraulic actuating cylinder arrangement.

Due to the arrangement described, the second hydraulic valve is arranged only under certain operating conditions of the hydraulic Actuator or the vehicle with hydraulic pressure medium supplied, namely in the course of a clutch actuation by means of the first Hydraulic actuator assembly. Every actuation of the gearbox via the second hydraulic valve arrangement thus activates a clutch ahead of the first hydraulic valve assembly. This ensures that a leakage loss on the second hydraulic valve arrangement only for a short time occurs during clutch actuation and therefore practically no longer weight. Therefore in a leakage calculation or balance sheet  practically only the first hydraulic valve arrangement is taken into account become. In addition, an actuation of the gearbox A clutch pedal actuation via the second hydraulic valve arrangement assumes a certain level of security against incorrect operation.

The switching valve is preferably a low-leak 2/2-way Valve, preferably of the type without a spool, for example a 2/2 Way ball seat valve. Such a valve is included in a leakage calculation not weight.

According to a first embodiment variant, the second hydraulic Actuator cylinder arrangement a lane selection cylinder and a switching cylinder, both of which can be controlled via the second hydraulic valve arrangement. The First hydraulic valve arrangement can be a 3/3-way proportional valve include to control a hydraulic pressure medium flow between the hydraulic source or a surge tank on the one hand and the first hydraulic actuating cylinder arrangement on the other hand. The second hydraulics valve arrangement can comprise a 3/3-way proportional valve for Control of a hydraulic pressure medium flow between the hydraulics source or a surge tank on the one hand and the second Hydraulic actuating cylinder arrangement, in particular the aisle selection cylinder, on the other hand.

According to another aspect, there is an actuation for the aforementioned operation direction suggested that in a hydraulic connection between the first hydraulic valve arrangement and the first hydraulic actuating cylinder arrangement voltage between a first switching state and a second Switching state switchable switching valve to interrupt this Hydraulic connection in the first switching state and to release it Hydraulic connection is provided in the second switching state, one Hydraulic connection between the first hydraulic valve arrangement and the second hydraulic actuating cylinder arrangement is provided, which hydraulics  Connection released regardless of the switching state of this switching valve or can be released.

According to the invention proposal, it is possible to use the first hydraulic actuating cylinder the arrangement and the second hydraulic actuating cylinder arrangement on the to control the first hydraulic valve arrangement, which ent ent significant reduction in the number of valves (with a correspondingly reduced ten costs) and accordingly a lower leakage loss overall results. For example, the second hydraulic actuating cylinder arrangement comprise an aisle selection cylinder and a shift cylinder, of which one, in particular the aisle selection cylinder, via the first hydraulic lines tilanordnung and the other, especially the shift cylinder, on the second hydraulic valve arrangement is controllable. For a defined Control of the first actuating cylinder arrangement and one cylinder (ins special lane selection cylinders), it is then sufficient, for example, the first Form hydraulic valve assembly with only one proportional valve, the both for controlling the first hydraulic cylinder arrangement and the serves a cylinder.

The proposal of the invention makes it possible in an advantageous manner Emergency actuation of the friction clutch without constant supply of hydraulics pressure medium and / or with at least reduced leakage loss from one hydraulic clutch holding the clutch in disengaged condition to provide arrangement.

The switching valve provided according to the invention is advantageous in that that it is designed as an inexpensive and low-leakage 2/2-way valve can be, preferably of the type without a spool, about a 2/2-way Ball seat valve. The leakage poverty of this valve is with regard to Clutch emergency actuation function is advantageous because the first hydraulic Actuator assembly kept under pressure for a long period of time  can be supplied without hydraulic pressure medium being supplied again got to.

In the actuator according to the second Aspect, the first hydraulic valve assembly can be a 3/3-way proportional comprise valve for controlling / regulating a hydraulic pressure medium flow between the hydraulic source or a surge tank on the one hand and the first hydraulic actuating cylinder arrangement or the second hydraulic Actuator arrangement, especially the aisle selection cylinder, other on the part of

For the hydraulic actuating device according to the invention proposed that at least one of the two hydraulic actuating cylinders be arranged tions, in particular the second hydraulic actuating cylinder arrangement, at least one double-acting, possibly as a switching cylinder serving, actuating cylinder includes a first and a second Proportional valve of the hydraulic valve arrangement assigned to the actuating cylinder tion, in particular the second hydraulic valve arrangement, a piston arrangement of the actuating cylinder via the first proportion nalventil in the sense of a movement of the piston assembly in a first position direction and via the second proportional valve in the sense of a movement the piston assembly in a second position opposite to the first direction can be acted upon with hydraulic pressure medium.

By providing a first and a second proportional valve, the Piston arrangement of the actuating cylinder is pressurized on both sides so that the piston arrangement (usually a simple piston) when reaching an intermediate position safely and without overshoots and the like are braked and held in this intermediate position can. The piston can then be clamped on both sides to a certain extent. There will be overshoots or general vibrations to a high degree avoided or suppressed. This "counteraction" by bilateral  Actuation of the piston arrangement using two proportional valves tile instead of just a proportional valve leads to the first aspect of Invention due to the switching valve to no practical relevance Increase in leakage losses.

The first and the second proportional valve can the actuating cylinder Supply hydraulic pressure medium with controllable / adjustable pressure. It can So, for example, so-called pressure control valves or pressure min act valves.

In general, the first hydraulic actuating cylinder arrangement is one over the first hydraulic valve arrangement controllable hydraulic slave cylinder may include that on a release fork and / or a release bearing Friction clutch works.

The invention also relates to a motor vehicle which, according to the invention, has a Actuator as described above and a Schaltge drives and has a friction clutch which by means of the actuating direction can be actuated.

The invention is illustrated below with reference to two in the figures Exemplary embodiments (with an embodiment variant) explained in more detail.

Fig. 1 shows a first embodiment of an actuator according to the invention for actuating a friction clutch and an automated transmission of a vehicle.

Fig. 2 shows a second embodiment of such a hydraulic actuator's rule, with an additional implementation variant is indicated.

Fig. 1 shows a hydraulic actuator with an assigned friction clutch 12 and an associated transmission 14 , both of which can be actuated by means of the actuator 10 to engage, remove or change a gear of the transmission by disengaging the friction clutch. In this context, one speaks of an "automated manual transmission" in contrast to a so-called "automatic transmission", in which an automatic gear change can be carried out by means of hydraulic actuation of brakes and clutches without having to actuate a friction clutch. In an automated manual transmission, a gear change takes place similarly to a manual transmission by actuating a shaft mechanism in conjunction with actuating a friction clutch, and identical or similar manual transmissions can be used.

The actuating device 10 comprises a control unit 16 , which is connected to further components of the vehicle 18 (symbolized by a rectangle), for example with various vehicle sensors and with a display unit 20 and a gear selector lever unit 22 , by means of which the control unit 16 is instructed and, if appropriate, a gear change can be triggered manually. The actuating device 10 has at least one operating mode in which the required gear changes are triggered fully automatically as a function of vehicle and engine conditions. It is conceivable that different operating modes are provided, for example a comfort-oriented operating mode and a sporty operating mode.

The control unit 16 controls a hydraulic pump motor 26 via a relay 24 by the relay 24 establishing or interrupting a power connection to a vehicle power supply in accordance with a control signal from the control unit. The motor 26 drives a hydraulic pump 28 which draws hydraulic oil from an expansion tank 32 via a filter unit 30 . The suctioned hydraulic oil is fed via a check valve 34 to a hydraulic circuit 36 to which a hydraulic accumulator 38 is connected. The control unit 16 detects the pressure in the hydraulic circuit 36 via a pressure sensor 40 and ensures that the hydraulic pressure remains in a predetermined pressure interval. A pressure relief valve 42 protects the hydraulic circuit and the components connected to it from overload.

On the hydraulic circuit 36 there is also a proportional 3/3-way valve 44 (also referred to as NZ; identifiable as belonging to the first hydraulic valve arrangement), which can be electrically controlled by the control unit 16 and which, according to the electrical control, has a defined hydraulic oil flow (volume flow Q [l / min]), either from the hydraulic circuit 36 , ie from a hydraulic source comprising the pump 28 and the hydraulic accumulator 38 to a hydraulic slave cylinder 46 (first hydraulic actuating cylinder arrangement), or from the hydraulic slave cylinder to the expansion tank 32 . The hydraulic slave cylinder 46 is assigned to the friction clutch 12 and actuates it via a release mechanism comprising a release fork 48 and a release bearing 50 . The current position of the release bearing 50 is fed back to the control unit 16 via a position sensor 52 . By controlling or regulating the hydraulic oil flow into the hydraulic slave cylinder 46 or out of it, the friction clutch 12 is engaged and disengaged in a defined manner.

A switching valve in the form of a 2/2-way valve 54 is further connected to the hydraulic circuit 36, which separates in a first switching state a further hydraulic circuit 56 (second hydraulic circuit 38) from the hydraulic circuit 36 (first hydraulic circuit 36) and in a second switching state connects the first hydraulic circuit 36 and the second hydraulic circuit 56 to one another.

The switching valve 54 is a hydraulic pressure-operated valve with a hydraulic control input which is connected via a hydraulic line 58 to a hydraulic line 60 connecting the proportional valve 44 to the hydraulic cylinder 46 . The switching valve 54 switches to the second switching state which establishes the connection between the two hydraulic circuits 36 and 56 when approximately 10% of the maximum hydraulic pressure prevails in the hydraulic slave cylinder 46 . If the hydraulic pressure drops below this threshold, the Schaltven valve 54 switches back into the first switching state separating the two hydraulic circuits 36 and 56 , the switching threshold for switching from the first to the second switching state being able to be somewhat higher than the switching threshold for switching from second to the first switching state. The second hydraulic circuit 56 is thus only in the course of a clutch actuation via the hydraulic circuit 36 with the hydraulic source 28 , 38 in connection.

At the second hydraulic circuit 56 , three proportional valves 62 (WW), 64 (SW1) and 66 (SW2) are connected, which form a second hydraulic valve arrangement. These valves are used to control a second hydraulic actuating cylinder arrangement assigned to the manual transmission 14 , with a hydraulic slave cylinder 68 , which serves as a selection angle cylinder or alley selection cylinder, and a double-acting hydraulic cylinder 70 , which serves as a switching cylinder or shift travel cylinder. The hydraulic slave cylinders 46 and 68 are both designed as single-acting hydraulic cylinders.

Of the valves of the second hydraulic valve arrangement, the valve 62 serves to actuate the selection angle cylinder 68 . This valve 62 (which is also designated WW in FIG. 1), like the valve 44, is a proportional 3/3-way valve which can be electrically controlled by the control unit 16 and which, according to the control, has a defined pressure oil flow Q lets through, either from the hydraulic source 28 , 38 via the hydraulic circuits 36 , 56 and a hydraulic line 72 to the hydraulic cylinder 68 or from this into the surge tank 32nd So that the spring-loaded piston having a Wählwin cylinder 68 can be actuated in a defined manner in order to actuate a switching mechanism 74 of the manual transmission 14 in a manner known per se in the sense of selecting an alley.

The hydraulic cylinder 70 (shift travel cylinder) is actuated via the proportional valves 64 and 66 (also designated with SW1 and SW2 in FIG. 1), which are pressure-feedback proportional pressure reducing valves (pressure regulating valves) which correspond to an electrical activation by the control unit 16 set a defined pressure in a respective hydraulic line 76 or 78 leading to the shift travel cylinder 70 by allowing hydraulic oil from the hydraulic circuit 56 to line 76 or 78 to pass through or hydraulic oil from this line 76 , 78 to the expansion tank 32 . The hydraulic lines 76 and 78 open out on different sides of a piston 80 of the double-acting hydraulic cylinder 70 .

In the course of a disengagement, when the second hydraulic circuit 56 is connected to the first hydraulic circuit 36 via the switching valve 54, the switching path cylinder 70 is actuated by the valves 64 and 66 assigned to the switching path cylinder 70 in order to set corresponding pressures on both sides of the piston 80 to move the piston within the cylinder housing and thus to actuate the switching mechanism 74 in the sense of engaging a gear, removing a gear or changing a gear. The pressure control provided for the actuation of the shift travel cylinder 70 corresponds to a force control of the actuation force exerted by the shift travel cylinder 80 on the switching mechanism 74 and is advantageous in that a targeted, the operating point adapted actuating force can be set. For example, to protect synchronizations in the transmission, synchronization can be carried out with a predeterminable force. It is also conceivable to control or regulate the actuating force depending on the driver.

A great advantage results from the fact that the piston 80 can be acted upon on both sides with hydraulic oil, so that the piston can be clamped on both sides. As a result, the piston can be braked better when it reaches an intermediate position to be approached, and can be held there without significant overshoots or vibrations in general.

In the embodiment shown, the double-sided pressurization of the piston 80 is made possible by the fact that two pressure control valves 64 and 66 (SW1 and SW2) are provided. The leakage inherent in proportional valves, which in the case of the provision of two pressure regulating valves instead of only one pressure regulating valve as a whole is correspondingly enlarged, does not pose any problem in the exemplary embodiment, since the second hydraulic circuit 56 only in the course of decoupling via the switching valve 54 and the first hydraulic circuit 36 is connected to the hydraulic source 28 , 38 . The leakage occurring during Auskup pelns is negligible, so that there is practically no increase in leakage. In addition, the proportional valve 62 (WW) is also connected to the second hydraulic circuit 56 , so that only the proportional valve 44 (NZ) is in constant communication with the hydraulic source 28 , 38 . In practice, only the leakage occurring at this valve 44 is significant and must be taken into account in a leakage calculation when designing the hydraulic pump 28 and the hydraulic accumulator 38 . There are correspondingly reduced requirements for the hydraulic pump 28 with its motor 26 , so that inexpensive components can be used without the risk of destruction due to the exceeding of a maximum duty cycle and corresponding overheating. There are also no disadvantages with regard to the overall service life of the electric motor if, due to the better leakage balance, an electric motor 26 corresponding to the reduced requirements is used. Instead of cheaper components, it is of course also possible to use components that meet higher requirements in order to increase the overall service life of the components.

The embodiment of FIG. 2 differs from the embodiment of FIG. 1 in that only three proportional valves are provided. For the exemplary embodiment in FIG. 2, the same reference symbols are used for identical or analog components, the reference symbols being increased by 100 in each case. Only the differences between the two exemplary embodiments are explained here; otherwise, reference is expressly made to the description of the first embodiment example of FIG. 1.

Two embodiment variants are shown in FIG. 2. The valve 154 corresponding to the valve 54 of the first exemplary embodiment is shown in dashed lines, since it is only provided according to a first embodiment variant of the exemplary embodiment in FIG. 2. According to a second embodiment variant of this exemplary embodiment, the switching valve 154 and the hydraulic line 158 connecting this valve with a hydraulic line 160 a connected to the valve 162 (WW) downstream hydraulic line 158 a , so that the hydraulic circuits 136 and 156 are always in connection with one another and can usefully be regarded as a common hydraulic circuit are. The advantages achieved by separating the hydraulic circuits 136 and 154 , which were explained on the basis of the first exemplary embodiment ( FIG. 1) and occur correspondingly in the second exemplary embodiment ( FIG. 2) according to the first embodiment variant, are dispensed with in the second embodiment variant, wherein However, a reduction in the total leakage losses occurring at the proportional valves results from the fact that a total of only three instead of four proportional valves are provided. This is explained in more detail below.

In the exemplary embodiment in FIG. 2, the proportional valve 162 (WW identifiable as belonging to the first hydraulic valve arrangement) (WW) serves simultaneously to control the hydraulic slave cylinder 146 assigned to the friction clutch 112 and to control the selection angle cylinder 168 . The proportional valve 162 (connected to the first hydraulic circuit 136 ), as well as the valve 62, a proportional 3/2-way valve with electrical control of the hydraulic oil flow, is followed by a 2/2-way valve 182 serving as a switching valve, which is shown in FIG is also referred to as NZ. In a first switching position, the switching valve 182 connects hydraulic line 160 a b between the valve 162 and the valve 182 to a hydraulic line 160 between the valve 182 and the hydraulic slave cylinder 146, so that a Hydraulikver connection between this hydraulic slave cylinder 146 and the flow control valve / flow control valve 162 is made. In a second switching state of the valve 182 , this connection between the lines 160 a and 160 b is interrupted, so that no clutch actuation is possible. A disengaged clutch can be kept in the disengaged state, however, by the valve 182 blocking the drain connection from the hydraulic slave cylinder 146 via the lines 160 b, 160 a and the proportional valve 162 . The switching valve 182 can be designed as an almost leak-free valve, for example as a ball seat valve, so that the clutch can be kept disengaged for extremely long periods of time without hydraulic oil (generally hydraulic medium) having to be supplied to the hydraulic slave cylinder 146 . The relatively large leakage of the proportional valve 162 is irrelevant.

Compared to the possible use of a 3/2-way valve instead of the 2/2-way valve 182 (NZ), the 2/2-way valve offers the advantage that it is cheaper on the one hand and has less leakage on the other and accordingly an emergency function given by the possibility of keeping the clutch disengaged can be maintained longer.

The selection cylinder 168 connected to the line 160 a connected to the proportional valve 162 via the hydraulic line 172 is always acted upon with hydraulic medium when a clutch is actuated by acting on the hydraulic slave cylinder 146 , since both hydraulic slave cylinders on the same working output A of the proportional valve 162 are connected, the selector cylinder 168 directly and the release cylinder 146 via the switching valve 182 . In fact, when disengaging or engaging, however, only the hydraulic slave cylinder (disengaging cylinder) 146 is actuated in the sense of a substantial movement of the respective cylinder piston, since the selector cylinder 168 of the shift mechanism 174 is held in its current position via an alley or the like. One also speaks of the selection cylinder 168 being “stored”.

The function when disengaging and engaging is as follows: The control unit 116 opens the valve 182 and controls / regulates the disengagement of the clutch by appropriately actuating the valve 162 . Thereafter, the valve 182 is closed and then the selection angle or the shift gate is set by the valve 162 . When engaging the valve 182 is opened and the clutch closed / closed by appropriate control of the valve 162 . At the same time, the selection cylinder is put down.

For the emergency function already briefly mentioned, the clutch 112 is opened when the system pressure is present by actuating the valves 162 and 182 . According to signal removal of the valves 182 and 162 (preference as to avoid first the switching valve 182 to a loss of hydraulic oil from the hydraulic slave cylinder 146 via the proportional valve 162), the clutch remains open, and the vehicle can move, in particular towed be.

It should also be mentioned that, in the case of the first embodiment variant, the hydraulic control line 158 could also be connected to the hydraulic line 160 b instead of to the hydraulic line 160 a. This would, that any on-off valve 154 leakage occurring the maximum Auskoppeldauer could reduce in case of emergency function disadvantage. An advantage of this, however, would be that even in the event of malfunctions in the actuation of the valves 182 and 162, actuation of the pressure control valves 164 , 166 associated with the double-acting hydraulic cylinder 170 (shift travel cylinder 170 ) and which are to be identified as a second hydraulic valve arrangement and connected to the second hydraulic circuit 156 is only possible if the clutch 112 is also disengaged.

For all exemplary embodiments and design variants and generally for the terminology used here, it must also be added that so-called servo valves or generally so-called continuous valves are also to be regarded as proportional valves in the sense of the invention. Furthermore, it should also be mentioned that in both exemplary embodiments, check valves 88 and 188 , which have not yet been mentioned, are provided, which serve to flush the cylinders 46 , 68 and 70 or the cylinder 170 in order, after filling the hydraulic system with hydraulic oil or an exchange of the hydraulic oil contained in the cylinders to flush them out. The reference numerals 90 and 190 designate a Gangerken voltage sensor, which indicates the switching state of the transmission 14 and 114 to the control unit 16 and 116 via a signal line. The signal line designated 92 and 192 symbolizes the possibility that further sensors are available which supply the control unit 16 or 116 with information, for example about conditions of the motor vehicle, about driving conditions such as speed, yaw rate etc., and / or about conditions of vehicle communication components, such as the vehicle engine. Not all hydraulic lines and control lines have been provided with their own reference numbers in the figures. In particular, the dotted hydraulic lines leading from the proportional valves to the expansion tank were not specially named. In addition to the pressure return valves provided in the pressure control valves 64 , 66 , 164 and 166 , which are generally shown as internal valve returns, further hydraulic connections can also be provided, in particular internal pressure equalization connections (for example for pressure equalization containers). The type of proportional valves can also be seen from the small diagrams shown in the figures next to the valves. The diagrams next to valves 44 , 62 and 162 are representations of the flow Q [L / min] as a function of an excitation current I [A] of a proportional magnet, and the diagrams next to valves 64 , 66 and 164 and 166 are are diagrams which give the pressure P [Bar] as a function of the excitation current I [A] of a proportional magnet. The schematic characteristic curves shown are only examples.

In summary, the invention relates to a hydraulic actuator direction for actuating a friction clutch of an automated Manual transmission of a vehicle with a hydraulic source of a first and a second hydraulic actuating cylinder arrangement and a first and one second hydraulic valve arrangement, each at least one proportional include valve. It is proposed to provide a switching valve to one of the hydraulic valve arrangements only occasionally with hydraulic medium in Dependence on one of the other hydraulic valve arrangement to supply adjustable hydraulic pressure with hydraulic medium. Furthermore, proposed a switching valve in a hydraulic connection between a a hydraulic clutch cylinder arrangement associated with a friction clutch and to provide at least one associated hydraulic valve to the Independent clutch in the sense of an emergency function when disengaged  of leakage losses of the at least one hydraulic valve keep can.

Claims (25)

1. A hydraulic actuator for actuating a friction clutch and an automated manual transmission of a vehicle, comprising:

• - a hydraulic source ( 28 ; 38 ; 128 , 138 ) for providing hydraulic pressure medium;
• - A first hydraulic actuating cylinder arrangement ( 46 ; 146 ) assigned to a friction clutch ( 12 ; 112 ) to be actuated
• - A second hydraulic actuating cylinder arrangement ( 68 , 70 ; 168 , 170 ) assigned to a switching mechanism ( 74 ; 174 ) of a manual transmission ( 14 ; 114 ) to be actuated;
• - A first hydraulic valve arrangement ( 44 ; 162 ) comprising at least one proportional valve (NZ; WW), via which hydraulic pressure medium from the hydraulic source ( 28 , 38 ) is actuated to actuate at least the friction clutch ( 12 ; 112 ) at least the first hydraulic actuating cylinder arrangement ( 46 ; 146 ) ; 128 , 138 ) can be fed;
• - A second hydraulic valve arrangement ( 62 , 64 , 66 ; 164 , 166 ) comprising at least one proportional valve (WW, SW1, SW2; SW1, SW2), via which at least the second hydraulic actuating cylinder arrangement ( 14 , 114 ) is actuated to actuate at least the gearbox. 68 , 70 ; 168 , 170 ) hydraulic pressure medium from the hydraulic source ( 28 , 38 ; 128 , 138 ) can be supplied;

marked by
a switching valve ( 54 ; 154 ) in a hydraulic connection between the second hydraulic valve arrangement ( 62 , 64 , 66 ; 164 , 166 ) and the hydraulic source ( 28 , 38 ; 128 , 138 ) for interrupting this hydraulic connection in a first switching state and for releasing it Hydraulic connection in a second switching state, the switching valve ( 54 ; 154 ) depending on a by means of the first hydraulic valve arrangement ( 44 ; 162 ) adjustable hydraulic pressure between the first and the second switching state is switchable. 2. Hydraulic actuating device according to claim 1, characterized in that the switching valve ( 54 ; 154 ) is a hydraulically controllable switching valve which has a hydraulic control connection which on one of the first hydraulic valve arrangement ( 44 ; 162 ) to the first hydraulic actuating cylinder arrangement ( 46 ; 146 ) leading hydraulic connection ( 60 ; 160 a, 160 b) is connected. 3. Hydraulic actuating device according to claim 1 or 2, characterized in that the second hydraulic actuating cylinder arrangement comprises an alley selection cylinder ( 68 ) and a shift cylinder ( 70 ), both of which can be controlled via the second hydraulic valve arrangement ( 62 , 64 , 66 ). 4. Hydraulic actuating device according to one of claims 1 to 3, characterized in that the first hydraulic valve arrangement ( 44 ) comprises a 3/3-way proportional valve (NZ) for controlling / regulating a hydraulic pressure medium flow between the hydraulic source ( 28 , 38 ) or / and a surge tank ( 32 ) on the one hand and the first hydraulic actuating cylinder arrangement ( 46 ) on the other. 5. Hydraulic actuating device according to one of claims 1 to 4, characterized in that the second hydraulic valve arrangement ( 62 , 64 , 66 ) comprises a 3/3-way proportional valve (WW) for controlling / regulating a hydraulic pressure medium flow between the hydraulic source ( 28 , 38 ) or / and a surge tank ( 32 ) on the one hand and the second hydraulic actuating cylinder arrangement ( 68 , 70 ) on the other. 6. Hydraulic actuating device according to claim 5, characterized in that the 3/3-way proportional valve (WW) controls the hydraulic pressure medium flow between the hydraulic source ( 28 , 38 ) and / and the pressure expansion tank ( 32 ) on the one hand and the gate selection cylinder ( 68 ) on the other hand / regulates. 7. Hydraulic actuating device according to one of the preceding claims, characterized in that the switching valve ( 54 ; 154 ) in the hydraulic connection between the second hydraulic valve arrangement ( 62 , 64 , 66 ; 164 , 166 ) and the hydraulic source ( 28 , 38 ; 128 , 138 ) is a 2/2-way valve. 8. Hydraulic actuating device according to claim 7, characterized in that the switching valve ( 54 ; 154 ) is a 2/2-way valve of the type without a spool. 9. Hydraulic actuating device according to claim 8, characterized in that the switching valve ( 54 ; 154 ) is a 2/2-way ball seat valve. 10. A hydraulic actuator for actuating a friction clutch and an automated manual transmission of a vehicle, comprising:

• - A hydraulic source ( 128 , 138 ) for providing hydraulic likdruckmedium;
• - A to be actuated friction clutch ( 112 ) assigned first hydraulic actuating cylinder arrangement ( 146 );
• - A switching mechanism ( 174 ) of a manual transmission ( 114 ) assigned to the second hydraulic Stellzylin deranordnung ( 168 , 170 );
• - A first hydraulic valve arrangement ( 162 ) comprising at least one proportional valve (WW), via which hydraulic pressure is used to actuate the friction clutch ( 112 ) and the gearbox ( 114 ) of the first hydraulic actuating cylinder arrangement ( 146 ) and the second hydraulic actuating cylinder arrangement ( 168 , 170 ) medium can be fed from the hydraulic source ( 128 , 138 );
• - An at least one proportional valve (SW1, SW2) encompassing a second hydraulic valve arrangement ( 164 , 166 ), via which at least the second hydraulic actuating cylinder arrangement ( 168 , 170 ) serves to actuate at least the gearbox ( 114 ) hydraulic medium from the hydraulic source ( 128 , 138 ) can be fed;

characterized in that
in a hydraulic connection ( 160 a, 160 b) between the first hydraulic valve arrangement ( 162 ) and the first hydraulic actuating cylinder arrangement ( 146 ), a switching valve (NZ) switchable between a first switching state and a second switching state for interrupting this hydraulic connection ( 160 a, 160 b) in the first switching state and for releasing this hydraulic connection ( 160 a, 160 b) is provided in the second switching state, a hydraulic connection ( 172 ) between the first hydraulic valve arrangement ( 162 ) and the second hydraulic actuating cylinder arrangement ( 168 , 170 ) being provided Which hydraulic connection ( 172 ) is released or can be released regardless of the switching state of this switching valve (NZ). 11. Hydraulic actuating device according to claim 10, characterized in that the second hydraulic actuating cylinder arrangement comprises a gate selection cylinder ( 168 ) and a shift cylinder ( 170 ), one of which via the first hydraulic valve arrangement ( 162 ) and the other via the second hydraulic valve arrangement ( 164 , 166 ) can be controlled. 12. Hydraulic actuating device according to claim 11, characterized in that the gate selection cylinder ( 168 ) via the first hydraulic valve arrangement ( 162 ) and the switching cylinder ( 170 ) via the second hydraulic valve arrangement ( 164 , 166 ) can be controlled. 13. Hydraulic actuating device according to one of claims 10 to 12, characterized in that the first Hydraulikventilanord voltage ( 162 ) comprises a 3/3-way proportional valve (WW) for controlling / regulating a hydraulic pressure medium flow between the hydraulic source ( 128 , 138 ) or / and a pressure expansion tank ( 132 ) on the one hand and the first hydraulic actuating cylinder arrangement ( 146 ) or / and the second hydraulic actuating cylinder arrangement ( 168 , 170 ) on the other hand. 14. Hydraulic actuating device according to claim 13, characterized in that the 3/3-way proportional valve (WW) controls the hydraulic pressure medium flow between the hydraulic source ( 128 , 138 ) and / and the surge tank ( 132 ) on the one hand and the gate selection cylinder ( 168 ) on the other / regulates. 15. Hydraulic actuating device according to one of the preceding claims, characterized in that the switching valve (NZ) in the hydraulic connection between the first hydraulic valve arrangement ( 162 ) and the first hydraulic actuating cylinder arrangement ( 146 ) is a 2/2-way valve. 16. Hydraulic actuating device according to claim 15, characterized in that the switching valve ( 54 ; 154 ) is a 2/2-way valve of the type without a spool. 17. Hydraulic actuating device according to claim 16, characterized in that the switching valve ( 54 ; 154 ) is a 2/2-way ball seat valve. 18. Hydraulic actuating device according to one of the preceding claims, characterized in that at least one of the two hydraulic actuating cylinder arrangements comprises at least one double-acting actuating cylinder ( 70 ; 170 ) via a first (SW1) and a second (SW2) proportional valve of the actuating cylinder ( 70 ; 170 ) associated hydraulic valve arrangement ( 64 , 66 ; 164 , 166 ) can be controlled, whereby a piston arrangement ( 80 , 180 ) of the actuating cylinder ( 70 ; 170 ) via the first proportional valve (SW1) in the sense of a movement of the piston arrangement ( 80 ; 180 ) in a first setting direction and via the second proportional valve (SW2) in the sense of a movement of the piston arrangement ( 80 ; 180 ) in a second, opposite to the first setting direction with hydraulic pressure medium. 19. Hydraulic actuating device according to claim 18, characterized in that the first hydraulic valve arrangement ( 44 ; 162 ) comprises at least one proportional valve (NZ, WW). 20. Hydraulic actuating device according to claim 18 or 19, gekennzeichet characterized in that at least the second hydraulic adjusting cylinder arrangement (68, 70; 168, 170) at least one double-acting positioning cylinder (70; 170), via a first (SW1) and a second (SW2) proportional valve of the hydraulic valve arrangement ( 64 , 66 ; 164 , 166 ) assigned to the actuating cylinder ( 70 ; 170 ) can be controlled, a piston arrangement ( 80 , 180 ) of the actuating cylinder ( 70 ; 170 ) via the first proportional valve (SW1) in the sense of a movement of the piston arrangement ( 80 ; 180 ) in a first actuating direction and by means of the second proportional valve (SW2) in the sense of a movement of the piston arrangement ( 80 ; 180 ) in a second actuating direction opposite to the first actuating direction. 21. Hydraulic actuating device according to claim 20, characterized in that the double-acting actuating cylinder (70; 170) as a shift cylinder (70; 170) is used. 22. Hydraulic actuating device according to claim 20 or 21, characterized in that the hydraulic valve arrangement assigned to the double-acting actuating cylinder ( 70 ; 170 ) belongs to the second hydraulic valve arrangement ( 64 , 66 ; 164 , 166 ). 23. Hydraulic actuating device according to one of claims 18 to 22, characterized in that via the first (SW1) and the second (SW2) proportional valve to the actuating cylinder ( 70 ; 170 ) hydraulic likdruckmedium with controllable / adjustable pressure can be supplied. 24. Hydraulic actuating device according to one of the preceding claims, characterized in that the first hydraulic adjusting cylinder assembly (46; 146) a through the first hydraulic valve arrangement (44; 162) actuatable hydraulic slave cylinder (46; 146), of a release fork ( 48 ; 148 ) and / or a release bearing ( 50 ; 150 ) of the friction clutch ( 12 ; 112 ) acts. 25. Motor vehicle with an actuating device ( 10 ; 110 ) according to one of the preceding claims and a manual transmission ( 14 ; 114 ) and a friction clutch ( 12 ; 112 ) which can be actuated by means of the actuating device ( 10 ; 110 ).