DE102006038446B4

Description

[0001] The present invention relates to a manual transmission according to the generic concept of claim 1.

State of the art

[0002] To reduce fuel consumption and also from aspects of shifting comfort, manual transmissions are increasingly being automated. In particular, the dual-clutch transmission offers a great deal of potential, since there is no interruption of traction during shifting, and the concept of parallel hybrid application through 2 clutches can separate the starter-generator from both the engine and driveline. For this actuators and sensors for the actuation of the clutch and gear shift necessary, with high dynamics and safety against incorrect operation. In hydraulic transmission medium as a venting of the hydraulic circuit is necessary.

[0003] From the DE 102004002064 A1 separate actuators for clutch and gearshift are known, which are housed in a housing. The clutch is actuated hydraulically by connecting an annular piston to the actuator via a long bore or channel in the transmission housing.

[0004] In the DE 10230501 A1 the clutch actuation via two position solenoid valves, each with a pressure transducer in the control circuit, wherein the pressure medium is provided via an electric motor driven pump with memory and pressure transducer. This system has a separate reservoir with level sensor, which is filled via an electromotive pump from the oil pan. The system has an additional line to the leak reservoir.

[0005]The DE 10120882 A1 discloses a hydraulic actuating system for a clutch which includes an open hydraulic circuit and in which the leakage oil of the clutch actuator is supplied to the clutch cooling circuit.

[0006]The DE 10215503 A1 describes an electro-hydraulic actuator with closed hydraulic circuit, in which an electric motor via a gear moves a plunger, which acts on a piston, which in turn promotes a pressure medium via a hydraulic line to a slave cylinder, which acts on a lever for clutch actuation.

[0007]The DE 4413999 B4 describes a similar pressure generation 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 power device, for example with compressed air as pressure medium and solenoid valve for control, to enable a quick disengaging. An incremental encoder on the electric motor serves as a position sensor to enable a position detection of the clutch together with the supplied drive current.

[0008] The DE 3607329 A1 discloses a control unit for a manual transmission, wherein by means of a pressure medium source, a pressure in a hydraulic line is constructed. When a maximum pressure in the hydraulic line is exceeded, the fluid pumped from the pressure medium source into the hydraulic line is fed back into a storage container via a pressure relief valve. Each actuator of the gearbox is connected via a magnetically controlled switching valve with the hydraulic line in connection, by means of the respective switching valve, a pressure in the downstream control unit is einregelbar.

[0009] The DE 102005019516 A1 Volkswagen's Self-Study Program 308 describes an electrohydraulic clutch, gearshift, and oil lubrication system for the gears for a direct shift transmission, which includes numerous solenoid valves for pilot control of sliders, electromagnetic pressure regulators, multiple pressure transmitters, relief valves, and a variety of pressure lines in the circuit board.

[0010] The EP 0818629 B1 discloses a venting method for a switchable valve assembly having a pressure valve whose switching pressure is higher than the working pressure. Optionally, additional switching valves for venting can be used.

Object of the invention

[0011]The object of the invention is to provide compared to the aforementioned prior art, a manual transmission, which is simple in construction, fail-safe and dynamic, and in which the clutch and gear actuation allows a specific switching characteristic.

[0012] This object is achieved with a transmission with the features of claim 1. Advantageous embodiments of this gearbox result from the features of the subclaims.

[0013] The transmission according to the invention is advantageously characterized by the fact that an exceptionally fast responding EC motor, as part of an electromotive actuator unit, time-shifted, in the so-called multiplex operation, both the clutches and the gearshift operated. The principle of operation of the control of the electromotive actuator based on the fact that needed for the clutch operation Force is proportional to the control pressure generated by the pressure generating unit. The proportionality factor results from the hydraulic transmission ratio of the system. The pressure generated in turn is proportional to the current supplied to the actuator. This results in a direct relationship between the coupling force to be set and the required power. Consequently, therefore, any desired coupling position can be approached via the regulation of the supplied current.

[0014] Coupling and gear plate are advantageously connected via several 2/2-valves. In the clutch operation of the required contact pressure via an electromotive actuator unit, consisting of electric motor motor and piston-cylinder unit, constructed regulated, while the inlet valve of the clutch actuator is open. When the required pressure is reached, the inlet valve is closed. This can prevent the engine from having to hold the clutch pressure required for power transmission. This switching behavior has a particularly advantageous effect on the power requirement, since the electromotive actuator unit only needs to be operated for a short time. In the coupling opening, alternatively, the pressure can be reduced controlled via the inlet valve and the electromotive actuator unit, or via the drain valve, which can be designed either as a clocked switching valve, or as a proportional valve. The provision of the clutch in the open state is supported by a spring. This type of coupling is known as "normally open". The controlled pressure build-up and down which can be achieved by the electromotive actuator is particularly important when certain positions of the coupling need to be precisely adjusted and timed accurately (e.g., sliding clutch, fully-engaged clutch).

[0015] Similarly, the gears are operated, in which case several valves are provided to switch between different gear positions.

[0016]Specifically, the exhaust valves of the clutches and gear shifter fulfill a dual function. The couplings act as safety valves to open the clutch in the event of a failed actuator or input valve, and at the same time to bleed the system during commissioning or service. In the gear actuators they act to relieve the actuator piston when actuated in one direction, and at the same time for ventilation.

[0017]Furthermore, the invention provides as a variant, the use of two actuators, each consisting of EC engine and piston-cylinder unit in front of dual-clutch transmissions. The use of two actuators allows the fully variable actuation of the two clutches. The gear shifters are usually operated with a time delay to the respective associated clutch, thereby advantageously all possible switching combinations can be displayed in multiplex mode.

[0018] This embodiment allows the operation of the gearbox, as well as both clutches in emergency, in case of failure of an actuator. This is achieved in this embodiment by interconnecting the two, separated in normal operation, hydraulic circuits, by means of a connecting valve, and operation of this hydraulic circuit with only one actuator. In contrast to the embodiment with only one actuator so in this embodiment, a redundancy of the actuators.

[0019]In addition, the invention includes the use of a pressure transducer for calibrating the current / pressure proportional adjustment of the actuating piston, as well as the special control of the electro-hydraulic actuator for sucking pressure medium for gear actuation.

[0020] Hereinafter, possible embodiments of the gearbox according to the invention will be explained in more detail with reference to drawings.

[0021] It shows:

1. First possible embodiment of an actuating device for a dual-clutch transmission, in which two clutches and four gear actuators are operated with an electromotive actuators;
2. a second possible embodiment of an actuator for a dual-clutch transmission, in which two clutches and four gear actuators are operated with an electromotive actuator, wherein the clutches are so-called wet-running clutches and means for lubricating and cooling the transmission gears is present;
3. third possible embodiment of an actuator for a dual-clutch transmission, in which two clutches and four Gears are operated with two electromotive actuators, in each case an operating device operates a functional group consisting of a clutch and two gear actuators, wherein the two function groups can be interconnected via a valve;
4. fourth possible embodiment of an actuator for a dual-clutch transmission, in which two clutches and four gear shifter are operated with two electromotive actuators, wherein the monitoring of the pressure levels of both circuits takes place with only one pressure sensor;
5. an exemplary, simplified representation of a gear change, which takes place in multiplex mode without traction interruption.

[0022] The 1 shows a first possible embodiment of the transmission according to the invention, which is designed as a double-clutch transmission.

[0023] In this case, an electromotive actuator operates 5 , which builds and modulates pressure in multiplex mode, two clutches 19 . 23 as well as the four gear regulators 32 . 33 . 34 and 35 ,

[0024] The structure of the controls 5 as well as the functionality is described in detail below.

[0025] To simplify the presentation, the couplings 19 . 23 only shown as blocks. It is known that hydraulic clutch plates of various types exist, for example as a ring piston actuator or lever operated actuator. The gear plates 32,33 are shown as a detail of an already known and the prior art design. To further simplify the figure, the gear shifter 34 . 35 only shown as blocks whose operation is identical to those of the first strand. It goes without saying that other hydraulic mechanisms for gear actuation can be operated with this concept.

[0026] The pump 1 , which is advantageously driven by a solenoid, promotes a pressurized fluid, which is advantageously a hydraulic fluid, from a reservoir 2 , And this leads via a line to a surge tank 3 to. The expansion tank 3 has a level sensor 4 to make sure there is always enough pressurized fluid in the system.

[0027] It goes without saying that in a leak-free system, the pump 1 and the reservoir 2 can be omitted if the system, eg via the expansion tank 3 , is filled.

[0028] The system has an automatic venting function, which is mainly useful during commissioning or after maintenance. This is when the solenoid valve is open 12 the system either by the statically applied pressure of the level of the surge tank 3 or by the aid of the actuating device 5 , flushed with pressurized fluid until no air is left in the system. Preferably, in the suction line of the pump 1 to provide suitable means (eg filters) to separate contaminants from the pressurized fluid and thereby prevent contamination of the system. Such a device is not explicitly shown.

[0029] The actuating device 5 for pressure build-up and for pressure modulation comprises an electric motor 6 , A piston-cylinder unit 7.9, preferably an integrated running control electronics 8th for the EC motor, which includes at least the power controllers and drivers for the motor, as well as the evaluation of the position detection of the piston 9 , Another design of the actuator can be an integrated control electronics 8th include, which in addition to the power controllers and the position detection also includes the signal processing.

[0030] The implementation of the rotary motion of the electric motor 6 in a translational movement of the pressure-generating piston 9 is preferably done by a spindle which is not shown here in detail. For the function of the actuator 5 is a Nachförderung of pressurized fluid from the surge tank 3 necessary. For this purpose, a corresponding construction of the piston 9 necessary, as for example in the bird technical book "motor vehicle technology" of Manfred Burckhardt in the chapter 10 , Page 299-304. Components of this construction include the piston seal 10 and a suitable bore attached to the well 11 and a balance hole 18 , By an appropriate design of the construction ensures that there is always pressure fluid in the working space of the cylinder.

[0031] By a forward movement of the piston 9 a system pressure is generated through which via hydraulic lines 14 and control valves, which are preferably designed as solenoid valves, the individual functional groups can be actuated. During a backward movement of the piston 9 is sucked forward pushed pressurized fluid, when all the solenoid valves of the pressure line are closed, while the solenoid valve 12 is open. About the opened solenoid valve 12 is the Nachsaugung ensured. With closed solenoid valve 12 is the Nachsaugung prevented.

[0032] A feather 13 , which is preferably arranged for reasons of space in the cylinder chamber, ensures that the piston 9 in the de-energized state, it is safely brought to the rear in a defined position (reference position).

[0033] The following is the function of the clutch operation based on the clutch 19 described in more detail. During clutch actuation, the valves for the gear regulators remain in the hydraulic line 14 closed, the supply valve for the clutch 23 is also closed.

[0034] By opening the solenoid valve 17 , which is preferably designed pressure-balanced and normally closed, and with simultaneous pressure build-up by the actuator 5 , the clutch will 19 guided by pressurization in a certain state (eg grinding clutch, closed clutch). The pressure is thereby by the actuator 5 regulated, and thus allows a time-controlled closing of the clutch. The solenoid valve 17 is closed. After reaching the desired coupling position, the valve can 16 getting closed. This requires the electric motor 6 The pressure does not build up and can be de-energized, which significantly relieves the electrical system.

[0035] After the clutch operation and with closed solenoid valves 16 and 17 can the pressure in the conduit part between the solenoid valves 16 . 20 and the couplings 19 . 23 vary, caused for example by heat input or by clutch grinding. To monitor the pressure in these parts of the lines, we prefer a pressure sensor 22 used. The function can be explained by the fact that the pressure applied to the clutch actuators is measured alternately at sufficiently short intervals. Here, for example, to measure the pressure at the clutch 19 all supply valves in the pressure line of the gear regulator as well as the valve 20 the clutch 23 closed while the solenoid valve 16 the clutch 19 is open. This raises the pressure sensor 22 the at the clutch 19 applied pressure. By a corresponding control of the valves 16 or 17 prevents unwanted pressure from occurring. Ideally, the pressure sensor 22 omitted when the pressure in the supply line between solenoid valve 16 and the clutch 19 , or between the solenoid valve 20 and the clutch 23 , at sufficiently short intervals by briefly opening the solenoid valve 16 respectively. 20 , and measuring the holding current at the actuator 5 can be determined with sufficient accuracy. On the relationship between holding current of the actuator 5 and pressure level will be discussed later in detail.

[0036] For the opening process of the clutch 19 There are various possibilities, which are explained in more detail below.

[0037] The coupling 19 is executed in this embodiment as "normally open", that is, the clutch is closed by applying pressure and opens automatically without pressure.

[0038] One way to open the clutch is now the solenoid valve 17 de-energized, whereby this opens and the pressure fluid from the self-opening coupling via the return line 15 in the expansion tank 3 is pressed. This function is also the emergency function for the system, which ensures that the clutch opens automatically in the event of a power failure.

[0039] In normal operation there is usually the requirement to open the clutch controlled. For this purpose, either the solenoid valve 17 operated with a PWM control, or the solenoid valve 17 is replaced by a proportional valve, which allows to reduce the pressure controlled. Again, the volume compensation via the return line 15 in the expansion tank 3 ,

[0040] Another way to reduce the clutch pressure controlled is the system pressure in the hydraulic line 14 by means of the actuating device 5 to raise to the level of clutch pressure, the valve 16 then open, and by retracting the piston 9 the actuator 5 to reduce the pressure regulated on the clutch, thereby opening the clutch.

[0041] It is known that clutches, in particular friction clutches, are subject to wear over their lifetime. The wear adjustment on the clutch discs is done automatically in this version. Due to wear on the clutch discs, the piston of the clutch actuator moves in the direction of the clutch discs. The migration of the actuating piston (slave piston), and the associated change in the volume in the actuator piston, is due to the running of pressurized fluid from the surge tank 3 compensated in the actuator piston cylinder.

[0042] In the following, the function of the gear shifter based on the gear selector 32 described in more detail.

[0043] The gear plate 32 in this embodiment consists essentially of a double cylinder / piston unit 28 which allows an actuator 29 move 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 middle position, shown here as a ball catch 30 ,

[0044] Now from the pressure generating actuator 5 generates a signal pressure, so can the piston of the gear actuator 32 by opening the solenoid valves 24 and 27 with closed solenoid valves 25 and 26 move to the right. The thereby displaced pressurized fluid passes through the return line 15 back to the expansion tank 3 , The solenoid valves 24 and 26 in the feed of this functional group are preferably carried out as normally closed. The valves in the drain of the solenoid valves 25 and 27 are preferably designed as normally open. After the gear change, all valves can be de-energized. The normally open valves 25 and 27 the expiration of the actuator with the expansion tank 3 connect, ensure that no unwanted pressure, for example by heating, can build up in the cylinder chambers. Should the actuator 29 be brought into the middle position or the left position, by means of the pressure-generating actuator 5 generates a control pressure, and the solenoid valves 25 and 26 opened while the solenoid valves 24 and 27 stay closed.

[0045] It goes without saying that the four solenoid valves 24 and 25 such 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.

[0046] The function of the overall system is described below with reference to a simplified example of a switching operation without interruption of traction based on 5 described. The example shows a shift from 2nd gear to 3rd gear.

[0047] As initial state, it is assumed that the 2nd gear is engaged and the clutch 23 closed is. The gear plate 32 for the 1st and 3rd gear is in neutral position, with the clutch 19 is open. This corresponds to a normal driving situation. To initiate the shift process is in the first step on the gear plate 32 the 3rd gear preselected, by pressure build-up of the actuator 5 and opening the valves 24 and 28 with closed solenoid valves 25 and 26 , After gear selection are advantageously the solenoid valves 24 and 26 closed, with the solenoid valves 25 and 27 can be opened to prevent an undesirable increase in pressure. Usually, the gears are designed so that they are self-hold when the gear is engaged.

[0048] The piston 9 the actuator 5 is reduced by the pressure fluid volume required for the gear position from the expansion tank 3 nachzuschnüffeln. The next step is by pressure build-up of the actuator 5 and opening the valve 16 when the valve is closed 17 the coupling 19 controlled closed, while at the same time by opening the valve preferably designed as a proportional valve 21 , with the valve closed 20 , the coupling 23 is opened regulated. After the clutch 19 is fully closed, the valve is held to hold the coupling force 16 closed. The monitoring of the control pressures of the two clutches and thus the transmission states takes place, as already described, via the pressure sensor 22 , Are the clutch 19 completely closed and the clutch 23 fully open, ie the gear change is completed, the piston 9 the actuator 5 retracted to the required for the clutch actuation pressure fluid volume from the surge tank 3 nachzuschnüffeln. In the last step can now the gear plate 34 be operated to interpret the 2nd gear and the actuator of the gear selector 34 to drive in the middle position.

[0049] It goes without saying that this description is shown greatly simplified, but real switching operations that can differ both in the time sequence and in the sequence can be realized with the illustrated embodiment.

[0050] Special cases such as opening both clutches at the same time can be done via the valves 17 and 21 be realized without restrictions. The simultaneous closing of both clutches can only be done with time restrictions by both clutches are fed alternately, gradually.

[0051] The 2 shows a second possible embodiment of the transmission according to the invention, which is also designed as a double-clutch transmission.

[0052] Unlike in 1 illustrated embodiment, this is a clutch assembly with wet-running clutches. This design corresponds to the prior art. Here, the clutches are flowed around for better heat dissipation with a cooling medium. In addition, the transmission in this embodiment has a device for lubrication and cooling of the gears, which also corresponds to the prior art.

[0053] The pump 36 is usually driven by the internal combustion engine due to their power requirements, but can also be driven by an electric motor. The pump 36 feeds a device for gear lubrication and cooling 38 , as well as a cooling circuit 40 for cooling the couplings 19 and 23 , The devices are controlled by solenoid valves 37 and 39 , which are preferably designed as 2/2-way valves. The 2 shows that the transmission according to the invention with the associated actuator 5 and their embodiments may be configured both as dry and as wet-running gear and clutch assemblies.

[0054] Furthermore, this arrangement differs from the arrangement in FIG 1 to the effect that in each coupling lead between the solenoid valves 16 and 20 or the associated couplings 19 and 23 one pressure sensor each 46 and 47 located. This arrangement allows the clutch states with closed valves 16 and 20 can be monitored at any time.

[0055] The 3 shows a third possible embodiment of the inventive transmission, which is also designed as a dual-clutch transmission. In this embodiment, two electromotive actuators operate 5 , which build and modulate pressure in multiplex mode, two independent pressure circuits in normal operation 44 and 45 , which in this embodiment each have a coupling 19 . 23 as well as two gear shifters 32 and 33 such as 34 and 35 assigned. The division into two independent pressure circuits and supply of each circuit by one actuator 5 makes the system redundant. In case of failure of an electromotive actuator 5 The two, in normal operation independent circles, by opening the valve 43 , Are connected to each other, so that the functions of the failed actuator can be taken over by the functional actuator. The solenoid valves 41 and 42 prevents the pressure built up by the functioning actuator from passing through the overflow hole 11 the malfunctioning actuator via the surge tank 3 is reduced. Furthermore, it is advantageous in this arrangement that both clutches can be brought independently and without restriction in any state. For example, both clutches can be closed simultaneously. In contrast, at the in 1 As shown execution, the two clutches are closed only gradually, with a time delay in multiplex mode.

[0056] The 4 shows a fourth possible embodiment of a dual-clutch transmission. In contrast to 3 this embodiment has only one pressure sensor 22 on, both pressure circuits 44 and 45 supervised. 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 was in 1 already sufficiently explained.

[0057] The 5 illustrates the relationships between the force of the individual actuators, such as gear selector and clutch plate, the timing of the actuators, and the travel of the individual actuators. On the basis of the dependencies between the actuating force, actuating pressure and power consumption of the pressure-generating unit, which can be seen in the diagram, and the actuating travel, it can be deduced that a sufficiently precise control of the actuators based on the state determination via the power consumption or power consumption of the pressure-generating unit is possible.

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