DE102006063073

Description

The present invention relates to a manual transmission according to the generic concept of claim 1.

A. State of the art

Manual transmissions are increasingly being automated to reduce consumption and also for reasons of shifting comfort. In particular, the dual-clutch transmission offers a great deal of potential, since there is no interruption in tractive effort when shifting gears, and the concept, when used for parallel hybrids, can separate the starter-generator from both the engine and the drivetrain by means of two clutches. This requires actuators and sensors to operate the clutch and gearshift, with high dynamics and safety against faulty operation. With hydraulics as the transmission medium, venting of the hydraulic circuit is necessary.

Separate actuators for clutch and gearshift are known from DE 102004002064 A1 and are housed in a single housing. The clutch is actuated hydraulically by connecting an annular piston to the actuator via a long bore or channel in the transmission housing. In DE 10230501 A1, the clutch is actuated via two position solenoid valves, each with a pressure transmitter in the control circuit, with the pressure medium being supplied via an electric motor-driven pump with accumulator and pressure transmitter. This system has a separate reservoir with level sensor, which is filled from the oil sump by an electric motor-driven pump. The system has an additional line to the reservoir for leakage oil. DE 10120882 A1 discloses a hydraulic actuation system for a clutch, which includes an open hydraulic circuit and in which the leakage oil from the clutch actuators is fed to the circuit for clutch cooling. DE 10215503 A1 describes an electrohydraulic actuating device with a closed hydraulic circuit, in which an electric motor moves a plunger via a transmission, which acts on a piston, which in turn delivers a pressure medium via a hydraulic line to a slave cylinder, which acts on a lever for clutch actuation. DE 4413999 B4 describes a similar pressure generation system in which an electric motor acts on a spindle with piston and additional plunger for piston actuation. To relieve the electric motor, the piston is connected to an auxiliary force device, for example with compressed air as the pressure medium and a solenoid valve for control, to enable rapid disengagement. An incremental encoder on the electric motor serves as a position sensor to enable position detection of the clutch together with the supplied drive current. DE 102005019516 A1 and Volkswagen's self-study program 308 describe an electrohydraulic system for controlling the clutch, gearshift and oil lubrication of the gears for a direct-shift transmission, which includes numerous solenoid valves for pilot control of sliders, electromagnetic pressure regulators, several pressure transmitters, pressure relief valves and a large number of pressure lines in the shift plate. EP 0818629 B1 discloses a venting method for a switchable valve arrangement with a pressure valve whose switching pressure is higher than the working pressure. Optionally, additional switching valves can be used for venting. DE 36 07 329 A1 discloses a control device for a manual transmission, in particular for a multi-stage gear transmission which can be shifted under load and has shift elements actuated by pressure medium for engaging or changing the individual gear stages. Task of the invention The task of the invention is to create a manual transmission which is simple in its design, fail-safe and dynamic, and in which the clutch and gear actuation enable a specific shift characteristic, in comparison with the aforementioned prior art. This task is solved according to the invention with a manual transmission having the features of claim 1. Furthermore, the task is solved by a method for operating a manual transmission having the features of claim 20. Advantageous embodiments of this manual transmission result from the features of the subclaims. The gearshift transmission according to the invention is advantageously characterized by the fact that an exceptionally fast-responding EC motor, as a component of an electromotive actuating device, actuates both the clutches and the gearshifts with a time delay, in so-called multiplex operation. The operating principle of the control of the electromotive actuator is based on the fact that the force required for clutch actuation is proportional to the signal pressure generated by the pressure generation unit. The proportionality factor results from the hydraulic transmission ratio of the system. The generated pressure, in turn, is proportional to the current supplied to the actuator. This results in a direct relationship between the clutch force to be set and the current required for this purpose. Consequently, any clutch position can be approached by controlling the supplied current. Advantageously, clutch and gear actuators are switched via several 2/2 valves. During clutch actuation, the required contact pressure is built up in a controlled manner via an electromotive actuating device consisting of an EC motor and a piston-cylinder unit, while the supply valve of the clutch actuator is switched open. When the required pressure is reached, the supply valve is closed. This prevents the EC motor from having to hold the clutch pressure required for power transmission. This switching behavior has a particularly beneficial effect on the power requirement, since the electromotive actuator only needs to be operated for a short time. At the clutch opening, the pressure can alternatively be released in a controlled manner via the inlet valve and the electromotive actuating device, or via the outlet valve, which can be designed either as a timed switching valve, or as a proportional valve. In this case, the return of the coupling to the open state is assisted by a spring. This type of clutch is known as "normally open". The controlled pressure build-up and release which can be achieved by the electromotive actuator is particularly important when certain clutch positions have to be set exactly and controlled precisely in terms of time (e.g. slipping clutch, fully closed clutch). The gears are operated in the same way, with several valves being provided here to switch between different gear positions. The exhaust valves of the clutches and gear actuators in particular have a dual function. In the case of the clutches, they act as safety valves for opening the clutch in the event of a failed actuator or input valve, and at the same time for venting the system during startup or service. In the case of the gear actuators, they function to relieve the load on the actuator piston when actuated in one direction, and at the same time to vent the system. Furthermore, the invention provides as a variant the use of two actuating devices, each consisting of an EC motor and a piston-cylinder unit, in dual clutch transmissions. The use of two actuating devices enables fully variable actuation of the two clutches. The gear actuators are usually actuated with a time delay in relation to the respective assigned clutch, which means that all possible shift combinations can be advantageously represented in multiplex operation. This embodiment allows the operation of the gearbox, as well as both clutches in emergency mode, in case of failure of one actuating device. This is achieved in this embodiment by interconnecting the two hydraulic circuits, which are separate in normal operation, by means of a connecting valve, and operating this hydraulic circuit with only one actuating device. In contrast to the design with only one actuating device, there is redundancy of the actuating devices in this design variant. In addition, the invention includes the use of a pressure transducer to calibrate the current/pressure proportional adjustment of the actuating piston, and the special control of the electrohydraulic actuating device to draw up pressure fluid for gear actuation. Possible embodiments of the manual transmission according to the invention are explained in more detail below with reference to drawings.

It show:

Fig. 1: First possible embodiment of an actuating device for a dual-clutch transmission, in which two clutches and four gear actuators are operated by an electromotive actuating device;

Fig. 2: Second possible embodiment of an actuating device for a dual-clutch transmission, in which two clutches and four gear actuators are operated by an electromotive actuating device, the clutches being so-called wet-running clutches and a device being provided for lubricating and cooling the transmission gears;

Fig. 3: Third possible embodiment of an actuating device for a dual-clutch transmission, in which two clutches and four gear actuators are operated by two electromotive actuating devices, in which case one actuating device in each case operates a functional group consisting of a clutch and two gear actuators, and the two functional groups can be interconnected via a valve;

Fig. 4: Fourth possible embodiment of an actuating device for a dual-clutch transmission, in which two clutches and four gear actuators are operated by two electromotive actuating devices, with the pressure levels of both circuits being monitored by only one pressure sensor;

Fig. 5:An exemplary, simplified illustration of a gear change, which takes place in multiplex operation without interruption of tractive effort. Figure 1 shows a first possible embodiment of the manual transmission according to the invention, which is designed as a dual-clutch transmission.

Here, an electromotive actuator 5, which builds up and modulates pressure in multiplex mode, operates a first clutch 19 and a second clutch 23 as well as the four gear actuators 32, 33, 34 and 35. The structure of the electromotive actuating device 5 and its mode of operation are described in detail below. To simplify the illustration, the clutches 19, 23 are shown only as blocks. It is known that hydraulic clutch actuators of various designs exist, e.g. as annular piston actuators or actuators operated via levers. The gear actuators 32, 33 are shown as a detail of an already known and prior art design. For further simplification of the figure, the gear actuators 34, 35 have been shown only as blocks, the operation of which is identical to that of the first string. It goes without saying that other hydraulic mechanisms for gear actuation can also be operated with this concept. The first pump 1, which is advantageously driven by a solenoid, delivers a pressure fluid, which is advantageously a hydraulic fluid, from a (pressure fluid) reservoir 2 and feeds it via a line to an expansion tank 3. The expansion tank 3 has a level sensor 4 to ensure that there is always sufficient pressure fluid in the system. It goes without saying that in a leak-free system, the first pump 1 and the reservoir 2 can be omitted if the system is filled, e.g. via the expansion tank 3.

The system has an automatic function for venting, which is mainly advantageous during commissioning or after maintenance work. When the first solenoid valve 12 is open, the system is ­flushed with pressurized fluid either by the statically applied pressure of the level of the expansion tank 3 or with the aid of the electromotive actuating device 5 ­until there is no more air in the system. Preferably, a suitable device (e.g. filter) ­is to be provided in ­the suction line of the first pump 1 in order to separate impurities from the pressure fluid, thereby preventing contamination of the system. Such a device is not explicitly shown.

The electromotive actuating device 5 for pressure build-up and pressure modulation comprises an EC motor 6, a piston-cylinder unit 9, 7, preferably integrated control electronics 8 for the EC motor 6, which include at least the power controllers and drivers for the EC motor 6, and the evaluation electronics for position detection of the piston 9. Another design of the actuating device can comprise integrated control electronics 8, which include signal processing in addition to the power controllers and position detection. The conversion of the rotational movement of the EC motor 6 into a translational movement of the pressure-generating piston 9 is preferably performed by a spindle which is not shown in detail here. For the function of the electromotive actuating device 5, a subsequent delivery of pressure fluid from the expansion tank 3 is necessary. For this purpose, an appropriate design of the piston 9 is necessary, as described, for example, in the Vogel technical book "Automotive Engineering" by Manfred Burckhardt in Chapter 10, pages 299-304. Components of this design include the piston seal 10 as well as an overtravel bore 11 and a balancing bore 18 at a suitable location. An appropriate design ensures that there is always pressure fluid in the working chamber A of the hydraulic control cylinder 7.

A forward movement of the piston 9 generates a system pressure by which the individual function groups can be actuated via hydraulic lines 14, 14' and control valves, which are preferably designed as solenoid valves. During a backward movement of the piston 9, pressure fluid pushed forward is sucked in when all solenoid valves of the pressure line are closed while the first solenoid valve 12 is open. The open first solenoid valve 12 ensures that the fluid is sucked in. When the first solenoid valve 12 is closed, the suction is prevented.

A return spring 13, which is preferably arranged in the cylinder chamber for reasons of space, ensures that the piston 9 is moved safely to the rear into a defined position (reference position) in the de-energized state.

In the following, the function of the clutch actuation is described in more detail on the basis of the first clutch 19. During clutch actuation, the valves for the gear actuators in the hydraulic main line 14 remain closed, and the supply valve for the second clutch 23 is also closed.

By opening the third solenoid valve 17, which is preferably pressure-balanced and closed when de-energized, and with simultaneous pressure build-up by the electromotive actuating device 5, the first clutch 19 is guided into a certain state (e.g. sliding clutch, closed clutch) by pressurization. The pressure is built up in a controlled manner by the electromotive actuating device 5, thereby allowing the clutch to be closed in a time-controlled manner. The third solenoid valve 17 is closed. After the desired clutch position has been reached, the second solenoid valve 16 can be closed. This means that the EC motor 6 does not have to build up the pressure any further and can be de-energized, which considerably reduces the load on the vehicle electrical system.

After clutch actuation and with solenoid valves 16 and 17 closed, the pressure in the part of the lines between solenoid valves 16, 20 and clutches 19, 23 may vary, caused for example by heat input or clutch slippage. A pressure sensor 22 is preferably used to monitor the pressure in these parts of the lines. The function is explained by the fact that the pressure applied to the coupling actuators is measured alternately at sufficiently small intervals. Here, for example, to measure the pressure at the first clutch 19, all supply valves in the pressure line of the gear adjusters as well as the fourth solenoid valve 20 of the second clutch 23 are closed, while the second solenoid valve 16 of the first clutch 19 is open. As a result, the pressure applied to the first clutch 19 is set at the pressure sensor 22. Appropriate control of the solenoid valves 16 or 17 prevents an undesired pressure from setting in. Ideally, the pressure sensor 22 can be omitted if the pressure in the supply line between the second solenoid valve 16 and the first clutch 19, or between the fourth solenoid valve 20 and the second clutch 23, can be determined with sufficient accuracy at sufficiently short intervals by briefly opening the second or fourth solenoid valve 16 or 20, and measuring the holding current at the pressure-generating unit or electromotive actuating device 5. The relationship between the holding current of the electromotive actuating device 5 and the pressure level will be discussed in detail later.

There are various possibilities for the opening process of the first coupling 19, which are explained in more detail below.

In this embodiment, the first clutch 19 is designed as "normally open", which means that the clutch is closed by applying pressure and opens automatically without pressure.

One way to open the clutch is now to de-energize the third solenoid valve 17, causing it to open and force the pressure fluid from the self-opening clutch into the expansion tank 3 via the return line 15. This function is also the emergency function for the system, which ensures that the clutch opens automatically if the power supply fails.

In normal operation, there is usually a requirement to open the clutch in a controlled manner. For this purpose, either the third solenoid valve 17 can be operated with a PWM control, or the third solenoid valve 17 is replaced by a proportional valve which makes it possible to reduce the pressure in a controlled manner. Here, too, the volume is balanced via the return line 15 into the expansion tank 3.

Another way of reducing the clutch pressure in a controlled manner is to raise the system pressure in the hydraulic main line 14 to the level of the clutch pressure by means of the electromotive actuator 5, then to open the second solenoid valve 16, and to reduce the pressure on the clutch in a controlled manner by moving back the piston 9 of the electromotive actuator 5, thereby opening the clutch.

It is well known that clutches, especially friction clutches, are subject to wear over their lifetime. In this design, the wear adjustment on the clutch discs takes place automatically. Wear on the clutch discs causes the piston of the clutch adjuster to move in the direction of the clutch discs. The movement of the actuator piston (slave piston) and the associated change in volume in the actuator piston cylinder is compensated for by the supply of pressure fluid from the expansion tank 3 to the actuator piston cylinder.

In the following, the function of the gear actuators is described in more detail on the basis of the gear actuator 32.

A gear actuator 32 in this embodiment consists essentially of a double cylinder/piston unit 28, which enables an actuator 29 to be moved linearly to the right or left. The actuator 29 itself usually has a position sensor 31, which is advantageously designed as a Hall sensor (not explicitly shown), and a device for mechanical locking in the center position, shown here as a ball detent 30.

If a signal pressure is now generated by the pressure-generating electromotive actuating device 5, the piston of the gear actuator 32 can be shifted to the right by opening the solenoid valves 24 and 27 when the solenoid valves 25 and 26 are closed. The pressure fluid displaced in the process returns to the expansion tank 3 via the return line 15. The solenoid valves 24 and 26 in the feed of this functional group are preferably designed as normally closed. The solenoid valves 25 and 27 in the outlet of the functional group are preferably designed as normally open. After a gear change, all valves can be de-energized. The de-energized solenoid valves 25 and 27, which connect the outlet of the actuator to the expansion tank 3, ensure that no undesirable pressure can build up in the cylinder chambers, for example due to heating. If the actuator 29 is to be moved to the center position or the left position, a signal pressure is generated by means of the pressure-generating electromotive actuating device 5, and the solenoid valves 25 and 26 are opened, while the solenoid valves 24 and 27 remain closed.

It goes without saying that the four solenoid valves 24 and 25 as well as 26 and 27, which are designed as 2/2 valves, can be replaced by two 3/2-way solenoid valves with the same functionality.

The function of the overall system is described below using a simplified example of a gearshift without traction interruption based on Figure 5. The example shows a shift from 2nd gear to 3rd gear.

The initial state is assumed to be that 2nd gear is engaged and the second clutch 23 is closed. The gear selector 32 for 1st and 3rd gear is in neutral position, with the first clutch 19 open. This corresponds to a normal driving situation. To initiate the shifting process, the 3rd gear is preselected in the first step via the gear selector 32, by building up the pressure of the electromotive actuating device 5 and opening the solenoid valves 24 and 28 with the solenoid valves 25 and 26 closed. After the gear has been selected, the solenoid valves 24 and 26 are closed in an advantageous manner, whereby the solenoid valves 25 and 27 can be opened to prevent an undesired increase in pressure. Usually, the gears are designed to be self-holding when the gear is engaged.

The piston 9 of the electromotive actuating device 5 is retracted in order to sniff the volume of pressurized fluid required for the gear position from the expansion tank 3. In the next step, the first clutch 19 is closed in a controlled manner by pressure build-up of the electromotive actuating device 5 and opening of the second solenoid valve 16 when the third solenoid valve 17 is closed, while at the same time the second clutch 23 is opened in a controlled manner by opening of the fifth solenoid valve 21, preferably designed as a proportional valve, when the fourth solenoid valve 20 is closed. After the first clutch 19 is completely closed, the second solenoid valve 16 is closed to maintain the clutch force. Monitoring of the actuating pressures of the two clutches and thus of the transmission states is carried out, as already described, via the pressure sensor 22. When the first clutch 19 is fully closed and the second clutch 23 is fully open, i.e. when the gear change has been completed, the piston 9 of the electromotive actuating device 5 is retracted in order to replenish the volume of pressurized fluid required for clutch actuation from the expansion tank 3. In the final step, the gear actuator 34 can now be actuated to disengage the 2nd gear and move the actuator of the gear actuator 34 to the center position.

It goes without saying that this description is presented in a highly simplified manner, but real switching operations, which can differ both in terms of timing and sequence, can be realized with the embodiment example shown.

Special cases, such as opening both clutches simultaneously, can be realized via solenoid valves 17 and 21 without restrictions. The simultaneous closing of both clutches can only be carried out under time restrictions by closing both clutches alternately, step by step.

Figure 2 shows a second possible embodiment of the manual transmission according to the invention, which is also designed as a dual-clutch transmission.

In contrast to the design shown in Figure 1, this is a coupling arrangement with wet-running couplings. This design corresponds to the state of the art. A cooling medium flows around the clutches to improve heat dissipation. In addition, the manual transmission in this embodiment has a device for lubricating and cooling the transmission gears, which also corresponds to the state of the art.

The second pump 36 is usually driven by the internal combustion engine due to its power requirements, but can also be driven by an electric motor. The second pump 36 feeds a device for gear lubrication and cooling 38, as well as a cooling circuit 40 for cooling the clutches 19 and 23. The devices are controlled by solenoid valves 37 and 39, which are preferably designed as 2/2-way valves. Figure 2 shows that the gearbox according to the invention with the associated electromotive actuating device 5 and its embodiments can be designed both as dry and as wet-running gearboxes and clutch arrangements.

Furthermore, this arrangement differs from the arrangement in Figure 1 in that a pressure sensor 46 and 47 is located in each coupling supply line between the solenoid valves 16 and 20 or the associated couplings 19 and 23. This arrangement makes it possible to monitor the coupling states at any time when solenoid valves 16 and 20 are closed.

Figure 3 shows a third possible embodiment of the manual transmission according to the invention, which is also designed as a dual clutch transmission. In this embodiment, two electromotive actuating devices 5, which build up and modulate pressure in multiplex mode, serve two pressure circuits 44 and 45 which are independent of one another in normal operation and to each of which, in this embodiment, a clutch 19, 23 and two gear actuators 32 and 33 and 34 and 35 are assigned. The division into two independent pressure circuits and the supply of each circuit by a respective electromotive actuator 5 makes the system redundant. In the event of failure of an electromotive actuator 5, the two circuits, independent in normal operation, can be interconnected by opening the twelfth solenoid valve 43, so that the functions of the failed actuator can be taken over by the functioning actuator. The solenoid valves 41 and 42 thereby prevent the pressure built up by the functioning electromotive actuating device 5 from being relieved by the overrun bore 11 of the non-functioning electromotive actuating device 5 via the expansion tank 3. Furthermore, an advantageous effect of this arrangement is that both clutches can be brought into any desired state independently of each other and without restriction. For example, both clutches can be closed simultaneously. In contrast, in the version shown in Figure 1, the two clutches can only be closed in stages, with a time delay in multiplex operation.

Figure 4 shows a fourth possible embodiment of a dual clutch transmission. In contrast to Figure 3, this embodiment has only one pressure sensor 22, which monitors both pressure circuits 44 and 45. The function is explained by the fact that the pressure applied to the clutch actuators is measured alternately, at sufficiently short intervals. The function of the pressure measurement with only one pressure sensor has already been sufficiently explained in Figure 1.

Figure 5 illustrates the relationships between the positioning force of the individual actuators, such as the gear actuator and clutch actuator, the time sequence of the positioning processes, and the travel of the individual actuators. Based on the dependencies between positioning force, signal pressure and power consumption of the pressure-generating unit and the travel distance shown in the diagram, it can be deduced that sufficiently precise control of the actuators is possible on the basis of state determination via the power consumption or current consumption of the pressure-generating unit.

The following are examples of embodiments according to the invention:

Design example 1:

Manual transmission, having at least one driven piston-cylinder unit (9, 7), it being possible to set a pressure, pressure build-up and/or pressure reduction in the working space (A) of the hydraulic control cylinder (7) by means of the driven piston (9) of the piston-cylinder unit (9, 7), characterized in that the working chamber (A) of the hydraulic control cylinder (7) can be connected successively and/or simultaneously by means of hydraulic main lines (14) and interposed controlled solenoid valves (16, 20, 24, 26) to actuating units of at least one clutch (19, 23) and at least one gear actuator (32-35) of the manual transmission.

Design example 2:

Manual transmission according to embodiment example 1, characterized in that the piston (9) is driven by means of an EC motor (6).

Design example 3:

Manual transmission according to embodiment example 2, characterized in that the EC motor (6) adjusts the piston (9) in the hydraulic control cylinder (7) via a spindle drive (S).

Design example 4:

Manual transmission according to one of the preceding embodiments, characterized in that the manual transmission has more than one piston-cylinder unit (9, 7), in particular two piston-cylinder units (9, 7), which are each driven by their own drive, in particular an EC motor (6).

Design example 5:

Manual transmission according to embodiment example 4, characterized in that the working chambers (A) of the hydraulic control cylinders (7) can be connected via at least one hydraulic line (11a) and at least one interposed controlled solenoid valve (41, 42).

Design example 6:

Manual transmission according to one of the preceding embodiments, characterized in that each actuating unit (St) has at least one hydraulic cylinder with a piston (StK) arranged therein, the actuating piston driving an actuator (29) of a gear selector (32-35) or a clutch (19, 23), and in that the piston forms with the hydraulic cylinder at least one hydraulic working chamber (StA) which can be connected to the working chamber (A) of the hydraulic control cylinder (7) via a hydraulic line (14, 14') with an interposed and controlled solenoid valve (16, 20, 24, 26).

Design example 7:

Manual transmission according to embodiment example 6, characterized in that the hydraulic working chamber (StA) of an actuator (St) can be connected to a hydraulic reservoir or expansion tank (3) via a return line (15, 15') with an interposed and controlled solenoid valve (17, 21, 25, 27).

Design example 8:

Gearbox according to one of the preceding embodiments, characterized in that the actuators (St) can be connected in a kind of multiplex operation via the controlled solenoid valves (17, 20, 24, 26) to a working chamber (A) of a piston-cylinder unit (9, 7), wherein during pressure build-up or pressure reduction in one or more actuator(s) (St) only this or these actuator(s) is/are (St) is/are connected to the working chamber (A) of the piston-cylinder unit (9, 7) via an open solenoid valve (17, 20, 24, 26), and the remaining hydraulic working chambers (StA) of the positioning units (St) are separated from the working chamber (A) of the piston-cylinder unit (9, 7) by closed solenoid valves (17, 20, 24, 26).

Design example 9:

Manual transmission according to one of the preceding embodiments, characterized in that the controlled solenoid valves (17, 20, 24, 26) are 2/2-way valves.

Embodiment 10:

Gearbox according to one of the preceding embodiments, characterized in that the working chamber (A) of a piston-cylinder unit (9, 7) is connected to a hydraulic main line (14), from which hydraulic lines (14') branch off, which connect the hydraulic main line (14) to the hydraulic working chambers (StA) of the actuating units (St), the controlled solenoid valves (17, 20, 24, 26), in particular 2/2-way valves, for opening or closing the hydraulic line (14') being arranged in the hydraulic lines (14').

Embodiment 11:

Manual transmission according to one of the preceding embodiments, characterized in that the working chamber (A) of a piston-cylinder unit (9, 7) is connected to a reservoir (2) or equalizing reservoir (3) for the hydraulic fluid via an equalizing bore (18) and a supply line (11b), in which a controlled first solenoid valve (12) is optionally arranged.

Embodiment 12:

Manual transmission according to embodiment example 11, characterized in that a first pump (1) conveys the hydraulic fluid from the oil sump (2) of the manual transmission into the expansion tank (3), the first pump (1) being controlled via a level sensor or level transmitter (4) integrated in particular in the expansion tank (3).

Design example 13:

Manual transmission according to embodiment example 11 or 12, characterized in that when the piston (9) of the piston-cylinder unit (9, 7) is retracted, a compensating bore (18) in the working chamber (A) is uncovered by the piston (9), via which the working chamber (A) is connected to the compensating reservoir (3) by the supply line (12b).

Embodiment 14:

Manual transmission according to embodiment 13, characterized in that the piston (9) of the piston-cylinder unit (9, 7) divides the hydraulic control cylinder (7) into a first working chamber (A) and a second working chamber (A2), the second working chamber (A2) being connected to the supply line (12b) by means of a channel, in particular in the form of a trailing bore (11), in the hydraulic control cylinder (7).

Embodiment 15:

Gearshift according to embodiment example 13 or 14, characterized in that a first 2/2 solenoid valve (12) is arranged in the supply line (12b).

Embodiment 16:

Manual transmission according to one of the preceding embodiments, characterized in that each clutch (19, 23) is assigned an electromotive actuating device (5) consisting of an EC motor (6) and a piston-cylinder unit (9, 7).

Design example 17:

Manual transmission according to one of the preceding embodiments, characterized in that an electric drive together with a piston-cylinder unit (9, 7) adjusts a plurality of clutches and gear actuators.

Design example 18:

Manual transmission according to one of the preceding embodiments, characterized in that a control unit determines the pressure in the working chamber (A) of a piston-cylinder unit (9, 7) and/or in the hydraulic main line (14) by means of a pressure sensor (22).

Design example 19:

Gearbox according to one of the preceding embodiments, characterized in that the control unit adjusts the pressure in the working chamber (A) on the basis of the motor current of the EC motor (6) driving the piston-cylinder unit (9, 7).

Embodiment 20:

Manual transmission according to embodiment example 18, characterized in that the control unit uses the pressure value determined by means of the pressure sensor (22) to calibrate the motor current-pressure control.

Embodiment 21:

Manual transmission according to one of the preceding embodiment examples, characterized in that the control unit for controlling the piston-cylinder unit (9, 7), in particular for adaptive clutch control, responds to a clutch characteristic curve or to a characteristic curve array in which the relationship between pressure and volume or piston travel of the piston (9) of the piston-cylinder unit (9, 7) is stored.

Embodiment 22:

Manual transmission according to one of the preceding embodiments, characterized in that the clutch or gearshift wear can be determined on the basis of one or more relationships, stored in the control unit, between pressure and volume or piston travel of the piston (9) of the piston-cylinder unit (9, 7) when a clutch or a gearshift is actuated.

Embodiment 23:

Manual transmission according to embodiment example 21, characterized in that the control unit takes into account the previously determined wear when actuating the piston-cylinder unit (9, 7) for adjusting a clutch or a gear selector.

Embodiment 24:

Manual transmission according to one of the preceding embodiments, characterized in that a second pump (36) delivers hydraulic fluid via separate hydraulic lines to the manual transmission elements, in particular to the clutch and the gears, for their lubrication and/or cooling.

Embodiment 25:

Manual transmission according to embodiment example 23, characterized in that demand-based control of the fluid flow is performed by means of solenoid valves.

Embodiment 26:

Manual transmission according to one of the preceding embodiments, characterized in that at least one piston-cylinder unit (9, 7) together with its drive(s) are arranged as a structural unit on the manual transmission.

Embodiment 27:

Gearbox according to embodiment 25, characterized in that the reservoir (2) and/or the solenoid valves are additionally arranged in the assembly unit.

Embodiment 28:

Gearbox according to embodiment example 25 or 26, characterized in that the control unit is additionally arranged in the assembly unit.

Embodiment 29:

Method for operating a manual transmission according to one of the preceding embodiments, characterized in that during the simultaneous actuation of two clutches, the pressure of one clutch actuator is controlled by an EC motor (6) and the associated piston-cylinder unit, and the other clutch actuator is controlled by valves.

Embodiment 30:

Method for operating a manual transmission according to one of embodiments 1 to 28, characterized in that the pressure control of the clutch adjuster is effected via proportional valves.

List of reference signs:

  • 1 first pump
  • 2Storage tank (e.g. transmission oil pan)
  • 3Balancing tank
  • 4Leveller
  • 5Electric motor actuator
  • 6EC engine
  • 7 Hydraulic control cylinder
  • 8Control electronics for EC motor
  • 9 Piston of the piston-cylinder unit
  • 10Piston seal
  • 11Outlet bore
  • 11aHydraulic line
  • 11bHydraulic line , supply line
  • 12 (first) 2/2 solenoid valve
  • 12bSupply line
  • 13Return spring
  • 14 Hydraulic main line
  • 14' Hydraulic line
  • 15Return line
  • 15' Hydraulic line
  • 16 (second) 2/2 solenoid valve
  • 17 (third) 2/2 solenoid valve or proportional valve
  • 18Balancing bore
  • 19 first clutch and clutch actuator
  • 20 (fourth) 2/2 solenoid valve
  • 21 (fifth) 2/2 solenoid valve or proportional valve
  • 22Pressure sensor
  • 23 (second) clutch and clutch actuator
  • 24 (sixth) 2/2 solenoid valve
  • 25 (seventh) 2/2 solenoid valve
  • 26 (eighth) 2/2 solenoid valve
  • 27 (ninth) 2/2 solenoid valve
  • 28cylinder /piston unit
  • 29Actuator
  • 30Ball catch
  • 31Position sensor for actuator
  • 32Gear adjuster 1
  • 33Gear adjuster 2
  • 34Gear adjuster 3
  • 35Gear adjuster 4
  • 36 second pump
  • 372/2 Solenoid valve
  • 38Gear lubrication / cooling
  • 392/2 Solenoid valve
  • 40Cooling circuit couplings
  • 41 (tenth) 2/2 solenoid valve
  • 42 (eleventh) 2/2 solenoid valve
  • 43 (twelfth) 2/2 solenoid valve
  • 44Pressure circuit 1
  • 45Pressure circuit 2
  • 46Pressure sensor
  • 47Pressure sensor
  • A (first) workspace
  • A2 (second) workroom
  • SSpindle drive
  • StPositioning unit
  • StAHydraulics Workroom
  • StKStellkolben
StZ Hydraulic cylinder or actuating cylinder

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