DE19900820B4 - Power assistance device for a transmission - Google Patents

Abstract

A power assist device for a transmission having a manual transmission includes a shift lever which is connected to a shift operation member of a transmission by a transmission means for transmitting a shift movement, and a servo drive for moving the shift operation member.

Description

The invention relates to a power assistance device for a manual transmission of a transmission according to the preamble of patent claim 1.

Such a power assist device is known from EP 0 692 658 A1 known.

Operating comfort is becoming increasingly important in the further development of motor vehicles. To better increase the ease of use of a shift lever and / or for better space utilization in motor vehicles, the shift lever can no longer be arranged directly on the center console between the driver's seat and passenger seat in vehicles, but ergonomically arranged close to the steering wheel. As a result, a shortening of the operating path of the operator's hand of the driver is advantageous, resulting in a short lever arm of the operating lever to an increased switching power of the driver.

The invention has for its object to form an aforementioned power assistance device for a manual transmission of a transmission in a motor vehicle such that even with short actuating travel on the shift lever or the shift lever a high degree of operating comfort is ensured and the operating force is significantly reduced.

This object is achieved with a power assistance device for a manual transmission with the features according to claim 1.

In this case, the power assist device can be applied to manual transmissions, the gears are engaged not only in a switching level by pulling and pressing the shift lever, but also for manual transmission with the H-shift pattern with multiple shift gates, the selection of the individual shift gates manually over a second Transmission device, for example via a Bowden cable or a linkage or the like, which is manually hinged without or by means of another switching power assistance by moving the shift lever, for example, perpendicular to the shift gates.

The power assist device may be equipped with a control unit in which positions of the shift lever are assigned to target positions of the shift operating member, wherein in a deviation of the actual position of the shift operating member from the desired position of the servo drive in the sense of reducing the deviation can be actuated whereby upon actuation of the shift lever by the servo drive, the shift actuator is tracked. It is advantageous to limit the mobility of the shift lever relative to the shift operating member by stops. The movement of the shift operating member may advantageously be provided by a a circuit sensor, for example a potentiometer, a Hall sensor or an incremental displacement sensor, the relative signal at certain switching states, for example, in the neutral position of the transmission is adjustable.

According to the invention, the shift operating member is a shift shaft of the transmission, which is rotatably connected to a drive member which is rotationally driven by a servo drive. A transmission device is connected to a mounted on the drive member lever with means for limiting the relative rotatability between the lever and the drive member, wherein between the lever and the drive member at least one energy storage acts in such a way that the lever when not from the shift lever forth a force is applied, is in an equilibrium position of the relative rotation range.

Furthermore, the lever may be rotatably mounted on the shift shaft and the lever having a pin which engages in a slot of the drive member, thereby resulting in a limited relative rotatability between the lever and the drive member, wherein between the lever and the drive member at least one Spring acts such that the pin is in the state in which the lever is not acted upon by the shift lever ago with a force in a central region of the elongated hole.

The drive member may advantageously be a toothed segment wheel which may be rotationally driven by a gear, such as a worm gear, from the servo drive configured as a servomotor such as an electric motor, a hydraulic motor or the like.

In the case of using the hydraulic principle, the drive member may be driven by a movable piston in two opposite directions piston / cylinder unit with two pressure chambers, which are connectable via one line with one of two driven by the servo drive reversing pump. Both lines can be connected to one another via a bypass line, in which a valve opening in case of malfunction of the power assistance device can be arranged.

The spring device which acts between the lever which articulates the transmission device and the switch actuating component can have a linear, progressive or degressive characteristic and be adapted to the shift feeling with the expectation of a certain force curve during the shift by the driver. It may also be advantageous in some cases to bias the spring device and form with a soft spring characteristic.

The control device for controlling the servo drive in one embodiment can do without a control device and for control at least two switches having - viewed from the neutral position - in each of the two directions of the shift within the limited relative rotation range between the lever and the drive member at one of the Balance position can be arranged around a differential way waypoint a switch that can activate the servo drive after exceeding a switching threshold when exceeding the differential travel in the direction of the switching movement and deactivate when falling below the switching threshold. In this case, to avoid limit cycles and circuit irregularities hysteresis with respect to the switching thresholds for switching on and off of the servo drive can be provided in such a way that the switching threshold for activating the servo drive with larger difference paths than the switching threshold for deactivating the servo drive. To adapt the servo assistance device to different shift travel in the transmission or to the configuration of the lever ratios, it may be advantageous, starting from the neutral position to design the differential paths in both directions of the switching movement differently.

Furthermore, a catch can be provided in the switching device, which can be arranged on the shift lever, on the switching shaft or on another component connected to the switching device and in the neutral position by a slightly increased operating or switching force to the driver indicates the neutral position. In the same way, the driver can also be signaled by the fact that in the neutral position of the shift lever, the assist torque of the servo drive is lowered. Advantageously, this option is selected when the power assistance device has, for example on the shift lever via a displacement sensor, so that in addition to the other specifications, the assist torque is set in dependence on the shift lever position with a reduced assist torque in the range of the neutral position.

The control of the servo drive in the form of an electric motor can be done by specifying the operating voltage or the current and thus a corresponding support torque can be set. It may be advantageous to design the motor not with the maximum vehicle electrical system voltage of the motor vehicle but the operating voltage in the range of half the vehicle electrical system voltage. Furthermore, it may be advantageous to filter the voltage applied to the electric motor by means of a first-order low-pass filter in order to adapt the course of the assist torque to the switching operation. Here, the use of a PT ₁ filter according to the equation t · dU / dt + U = U _B with the time constant t, the differential quotient of the voltage U acting on the motor after the time t dU / dt and the operating voltage U _B , wherein the time constant t can be matched to the switching device. The realization of the filter can be done electronically or by calculation, for example in a control unit.

In conjunction with the use of sensors and other operating parameters, which may be particularly advantageous for adjusting the assist torque of the servo drive, provide a controller having a microprocessor with associated memories and signal inputs and outputs, this controller being in a central processing unit of the motor vehicle or separately can be maintained for the power assistance device, in which case networking with other computer units or a central computer unit can be advantageous. In the memory, current data and the desired state values for controlling the servo drive and sensor signals and their derived arithmetic values are stored, and it may be very advantageous for security reasons to store corresponding values, maps and / or algorithms redundantly and with a different redundancy values Plausibility check the likely correct value to use, in relevant cases, the triggering of driver information can be beneficial.

According to another idea, an embodiment may be configured such that the power assist device is provided with at least two displacement sensors that detect at least the movement of the shift operation member and the shift lever during a shift operation. In this case, the circuit sensor or the shift lever sensor may be configured as a sensor that detects the path taken by the spring device.

Another displacement sensor can detect the selection of the shift gate as a selection sensor, this sensor being mounted both on the shift lever or in the region of the transmission or on a component arranged therebetween, so that by evaluating the signals of the shift lever sensor and / or the Circuit sensor can be made a clear statement about the engaged gear.

The support torque of the servo drive can advantageously be carried out as a function of various operating parameters. Thus, for example, the assist torque of the servo drive in response to the covered during the switching path or angle of rotation of the drive member relative to the shift operating member are set, wherein after actuation of the shift lever via the transmission unit, a lever, for example, against the action of a disposed between the lever and the shift operating member spring means is actuated , Wherein the lever is arranged rotatably limited on the Schaltbetätigungsbauteil and thereby rotated by the spring force of the spring device relative to the drive component and thus one of a sensor, such as the circuit sensor, received control variable as a path or angular difference for the activation of the servo drive delivers depending on a corresponding support torque can be transmitted to the drive component.

Another embodiment of the formation of a manipulated variable for the servo drive and its assist torque can be carried out as a function of a distance from the path or angle of rotation of the mounted on the drive component lever of the transmission device minus the path or angle of rotation of the drive component differential path during the switching operation. A large differential path or difference angle between the shift lever and the shift operating component can generate a large assist torque, which decreases with increasing approach to the equilibrium state between the predetermined size of the shift lever and the tracked by the drive component Schaltbetätigungsbauteil.

Also advantageous may be the setting of the assist torque of the servo drive in response to a determined from the path or angle of rotation of the shift lever minus the path or angle of rotation of the drive component differential path during the switching operation. Here, a large difference in control between the setpoint (shift lever) and the stock size (drive component) can be readjusted directly.

To determine the difference paths at least signals of the circuit sensor and the shift lever sensor are included and processed in the control unit taking into account the lever geometries. In addition, it may be advantageous to include further operating parameters in the calculation of the drive signal of the servo drive. Thus, for example, the assist torque of the servo drive can be calculated as a function of the signal of the selection sensor in order to take into account the different effort in the different shift gates.

Further, the assist torque value alone or in conjunction with other operating parameters may be calculated and used to adjust the assist torque depending on the speed at which the shift lever is moved. The determination of the speed can be done from a time-dependent measurement of the distance to be covered by the shift lever during a shift, wherein advantageously the speed can be determined via a DT ₁ filter from the distance traveled from the signal of the shift lever sensor. A shift intent of the driver can be detected when a predetermined speed threshold and / or a predetermined threshold of the shift lever is exceeded, wherein one or both signals of exceeding the threshold can be tuned that a distinction between accidental shaking of the shift lever by vehicle movements and a shift intention can and the servo drive is activated only with actual switching intention.

An idea further provides a power assist device for a manual transmission including a shift lever movable relative to the shift operating member in its two opposite directions of actuation and connected to a shift operating member of a gearbox by means of transmission means for transmitting a shift movement, frictionally coupled to the shift operating member by a transmission means connected servo drive for moving the switching actuator, and a control device for controlling the servo drive before. The support torque of the servo drive is set in the embodiment in an advantageous manner depending on at least one force and a displacement sensor, wherein the force sensor can be arranged on the drive member and the displacement sensor as a shift lever sensor. The assist torque is advantageously set in response to the operating force acting on the shift lever.

It may also be advantageous to take into account a temperature dependence of the servo assistance device in the calculation of the drive signal for the assist torque, wherein the compensation of the temperature dependence by means of an operating temperature, which may be, for example, a transmission oil, engine oil and / or cooling water temperature occurs. Also, calculation models that include at least one or a combination of the existing in the vehicle Rate temperature measuring devices, and determine a relevant for the circuit temperature size to compensate for the temperature dependencies of switching operations are used. The determined temperatures can be stored as a temperature map in a memory. A compensation can be done, for example, by the servo drive from a temperature threshold to lower temperatures an additional support torque as an offset or by the drive signal for the servo drive is acted upon by a temperature-dependent factor.

The input of the desired states for the drive control as well as for other operating parameters is advantageously carried out during initial startup and / or when restarting. Here, for example, the desired positions of the shift lever corresponding gears and / or a neutral position of a setting can be assigned without engaged gear and stored in a memory. Nominal positions for the assigned gears can correspond to a H-circuit diagram.

Among other things, to reduce the computer power can be assigned to the neutral position forwards and backwards inlaid passages in the form of one gang group in each case a mean desired position and stored in a memory.

Furthermore, for example, for specific control of the servo drive in the field of synchronization of the transmission when changing gear already at the first commissioning - and later continuously at predetermined time intervals for updating certain positions of the shift lever synchronization positions for the individual gears or gear groups are assigned and stored in a memory. Advantageously, at the synchronization positions, the assist torque of the servo drive can first be lowered until the synchronization is found and then increased again, wherein an additional force sensor can be saved by defining the synchronization positions.

To avoid hard stops on the synchronizer, the servo drive can automatically disengage the engaged gear and move the shift operating member in the neutral position when detected switching intent. The shift lever can be coupled out or carried. The driver then switches to the desired gear with the assistance of the servo drive.

Furthermore, it may be advantageous to correct the sensor signals and / or the difference paths determined therefrom as a function of wear conditions, since, according to experience, changes in the mechanical components due to wear occur as the operating time of the transmission and the circuit increase. Advantageously, setpoint states fixed during commissioning are continuously replaced by current values that are determined from balancing.

Another aspect of safety is the ability to allow the servo drive and thus easier switching only if a driver has taken place in the vehicle or on the driver's seat. The detection of this condition is expediently carried out from an operating variable which allows this inference, for example when a clutch switch indicates the actuation of the clutch and / or when the brake light switch is actuated and the like. Particularly good security results in the use of a force sensor or a switch in the seat, especially if this is set so that children or animals in the vehicle sensor or switch can not trigger.

Another safety aspect may be the prevention of the function of the starter for starting the internal combustion engine, as long as a gear is engaged, wherein the shift lever sensor and / or the selection sensor can provide a corresponding signal for triggering the starter lock. When disengaged clutch can be released by the evaluation of a clutch switch, Ausrücklagersensors or the like start by means of the starter yet, since the risk of unwanted movement of the vehicle is not given. Power assistance device, in particular according to one of the preceding claims, wherein the neutral position is detected by means of the shift lever sensor.

Following another idea, the operating force of the shift lever, so the force to be applied by the driver to be switched manually, for example, via a tap changer or a potentiometer be adjustable, the switch or potentiometer signal is included in the calculation of the assist torque, so that the driver the shift force individually can adjust. It may also be advantageous to adapt the shift force automatically by a self-adaptation to the driver, with different, conclusions on the driver profile permitting influencing variables, such as the type of movement of the pedals - for example, detectable via throttle sensor, clutch sensor or the like -, the steering wheel - detectable via a steering angle sensor - can be evaluated. The actuation force of the servo-assisted manual transmission lies in a range between 10 N and 100 N.

Advantageously, the present servo drive provides additional information to the driver by the servo drive suspending, amplifying or reversing the assist torque during a particular event or at a given time. Thus, for example, the moment of support can act to reinforce the momentary overpressing of the switching device and expose it after a long time or build up a counter-torque. Furthermore, the controller may output a drive signal to the servo drive that builds up a counter-torque or suspends the action of the servo drive when the driver is shifting into an improper gear, wherein the controller determines an engaged gear with no-slip clutch from the engine speed and the transmission output speed and In the control unit of the vehicle speed dependent, impermissible gears can be stored.

Likewise, the servo drive in load shifts that are made with the clutch closed or not fully open, do not support the switching movement of the driver or act on an opposing support torque, which - as in the choice of an impermissible gear - can be distinguished as serious the faulty operation and dependent on it only the support of the switching process is omitted or a counter-torque can be applied. The assessment of the presence of a power shift operation can be detected in the control unit by evaluating at least one sensor or switching signal of the following operating parameters: engine torque, throttle valve angle, accelerator pedal angle, clutch release travel, clutch pedal travel, neutral position, clutch position. The failure to provide the power assistance or the application of a counter-torque can be advantageously controlled so long until the load switching conditions are canceled. In addition, it is possible to increase the assist torque with decreasing degree of the load circuit in response to a signal representing the degree of load switching.

If the driver wants to start in an inappropriate gear, here also the servo drive can be suspended or acted upon with a counter-torque, which can be allowed as starting gears from the state in the control unit with respect to the translation to slow the first two gears and a reverse gear.

Another advantage of a present power assist device over vehicles with other shifting aids may be the possibility of emergency operation in the event of a defective shifting device. Thus, in case of failure of the servo drive - but with increased switching forces - with the shift lever as with a manual circuit makeshift continue, the servo drive is not designed to be self-holding. For ease of actuation of the shift lever, a clutch between the drive member and the shift operating member can be arranged in addition, which can be opened with defective drive, whereby the load torque is eliminated by the servo drive and a self-holding design of the servo drive is not a hindrance.

Furthermore, a defective transmission device, for example, in demolition of the Bowden cable for the circuit device, when using a servo assistance device with two displacement sensors of the shift lever sensor serve as a setpoint generator with which the servo drive is tracked, which is designed so that it can take over the complete switching power. The circuit sensor acts as a control sensor for the path traveled by the shift operating member.

It may be advantageous to perform the switching to emergency programs in case of defects without an abrupt stop of the vehicle, the driver - as in other cases of defects also advantageous - as early as possible to inform or warn, with such messages according to the prior art means Light or acoustic signals and / or optionally with information texts on displays and / or monitors can be output, the type of message depending on the urgency can be multi-level, for example, an indication of a necessary workshop visit with low priority and the demolition of the Bowden cable be taught with high priority.

Further advantageous may be the performance of plausibility checks to determine the functionality of sensors, such as the shift lever sensor, the circuit sensor and / or the dial sensor. In this case, for example, the path lengths of the circuit sensor and the shift lever sensor, taking into account the leverage ratios to determine the plausibility of these are compared. Furthermore, the signal of the Wählsensors with the engine speed and / or with the wheel speed and / or the speedometer speed, taking into account the ratios for determining the plausibility of the engaged gear and / or the speeds are used. Similarly, during the activation of the servo drive, a check is made for changing a path length to be effected by the servo drive, whereby it can be determined whether the servo drive is functional. In addition, the response of the servo drive to the drive signal in conjunction with the traveled Way, for example, serve as a measure of the aging of the drive and / or the maintenance condition.

To prevent it from remaining in the event of a malfunction of the shift lever sensor, it may be advisable to form a substitute value from the movement of the shift sensor taking into account the lever ratios acting between the two sensors and optionally the stiffness of the spring device. In case of failure of the circuit sensor, a substitute value may be formed from the movement of the shift lever sensor taking into account the leverage ratios effective between the sensors and optionally the stiffness of the spring means. A defect in the transmission device can be detected by a plausibility check of the two signals emitted by the circuit sensor and the shift lever sensor.

In order to promote a special driving style, for example with regard to the saving of energy or for a sporty driving style, the driver can be proposed a possibly more favorable gear compared to the inserted, with appropriate proposals from the control unit with the aid of further operating data and sensor signals present in the vehicle, such as throttle position, engine speed, transmission output speed, dial sensor, shift lever sensor.

For reasons of safety and comfort, it may also be advantageous if the control unit automatically disengages an engaged gear by means of the power assistance device in selected driving situations and switches to the neutral position, for example if the engine stalled due to a speed that is too low for the engaged gear threatening. Furthermore, in heavy braking maneuvers the engaged gear can be disengaged, especially if the brakes are additionally burdened with load torque of the engine. Even with a response of an anti-lock device disengagement of the engaged gear can be beneficial.

Advantageously, further elements can be actuated with the control device, for example an electronically controlled fuel supply, such as throttle control or injection device, which is controlled by a further control device and is actuated, for example, by an electric motor.

Advantageous embodiments and further developments of the present power assistance apparatus and their advantages will be explained below with reference to the accompanying figures.

In the figures represent:

1 the basic structure of a first embodiment of the power assist device,

2 Details of the connection of the transmission device to the transmission,

3 a sensor cooperating with the shift lever,

4 and 5 different characteristics of the spring device,

6 and 7 schematic views of two different embodiments of the spring device,

8th the basic structure of another embodiment of the power assist device,

9 Force path characteristics to explain the function,

10 a flow chart to explain the function,

11 a flowchart of another embodiment of the power assist device,

12 and 13 Force path characteristics for function explanation,

14 and 15 two further flow charts,

16 one opposite 2 modified embodiment of the power assist device,

17 a schematic representation of an embodiment of the power assistance device with control unit,

18 a schematic representation of an embodiment of the power assistance device without displacement sensors,

19 a schematic representation of an embodiment of the power assistance device without spring device,

20 a diagram of the drive signal in response to the path of the shift operating member,

21 a course of a drive signal as a function of the travel of the shift lever in the region of the neutral position,

22 a course of the drive signal as a function of the differential path between shift operating component and shift lever,

23 a flow chart for detecting the intention to shift,

24 a flow diagram for the detection of the switching state,

25 a flowchart for the sequence of a switching operation in dependence on the switching state,

26 a flowchart for the dependence of the power assistance on the presence of a driver,

27 - 29 Flow diagrams for preventing a load circuit,

30 a flow chart of a procedure for the automatic disengagement of an inserted gear,

31 a flowchart of a procedure for handling the startup and

32 a flow chart of a procedure for starting the starter.

According to 1 is at the steering column 2 a motor vehicle, a shift lever 4 attached, via Bowden cables 6 and 8th with a manual transmission 10 connected is. More precise is the shift lever 4 according to a H-circuit diagram movable, wherein one of the Bowden cables, in the example shown, the Bowden cable 6 the movement of the gear lever 4 within the selector gate on a Wählbetätigungsglied 12 transfers and the other Bowden cable 8th the switching movement of the shift lever 4 to a switch actuator 14 transfers. It is understood that the Bowden cables 6 and 8th by linkage or other transmission devices, such as hydraulic transmission equipment may be replaced.

The movement of the shift actuator 14 is powered by a servo drive 16 supported by a control unit 18 which is controlled via a line 20 with a shift lever sensor (in 1 not shown) and via another line with a in 1 Also not shown circuit sensor for detecting the position of the switching actuator 14 connected is.

2 shows the connection of the Bowden cable 8th to the switch actuator 14 , which is formed in the example shown as a switching shaft.

With the switching shaft 14 is rotatably effective as a drive component Zahnsegmentrad 22 connected, its teeth with a pinion 24 meshes, that is the output of a worm gear 26 forms, of the trained as an electric motor servo drive 16 is driven. The rotational position of a rotationally fixed with the pinion 24 and thus also the toothed segment wheel 22 connected component of the described drive is a sensor 30 captured with the control unit 18 is connected to and provides pulses to which the position of the switching actuator 14 can be deduced in a conventional manner, for example by pulse counting. The sensor 30 thus forms a circuit sensor for detecting the movement or the rotational position of the shift shaft 14 ,

Coaxial with the selector shaft 14 is a lever 32 pivotally mounted, the means of a pin 34 in a on the Zahnsegmentrad 22 with respect to the axis of the switching shaft 14 in the circumferential direction extending slot 36 intervenes.

In the lever 32 and the sector gear 22 recesses are formed in an overlapping manner, in which one on the lever 32 and at the toothed segment wheel 22 supporting spring 38 working in a rest position, in the Bowden cable 8th No force on the lever 22 works, the lever 22 relative to the toothed segment wheel 22 holds in a position in which the pin 34 in the middle of the long hole 36 located.

3 shows the one in the fulcrum 40 mounted shift lever 4 with its connection to the Bowden cable 8th or the rope 42 this Bowden cable. Next is in 3 the shift lever sensor 44 represented by a connecting part 46 with the shift lever 4 connected and recorded its position. The shift lever sensor 44 For example, it can be designed as a rotary potentiometer or for generating digital output signals as a light barrier, which scans the movement of a segment wheel.

The function of the described arrangement is as follows:
In the control unit 18 a table is filed in which each position of the switching lever moved in Schaltbetätigungsrichtung 4 the (determined by the shift lever sensor 44 ) a desired position of the shift shaft 14 assigned. The actual position of the selector shaft 14 is from the circuit sensor 30 detected. In the event of a deviation between the setpoint and the actual value of the position of the selector shaft 14 becomes the servo drive 16 according to the control unit 18 implemented control (P control, I control, PID control, etc.) controlled so that the deviation between the setpoint and actual value decreases. It is understood that the control unit 18 purely analog can be constructed by analog sensors 30 and 44 used, for example, calibrated such that their Output signals match if the setpoint and the actual value match.

Due to the fact that the toothed segment wheel 22 the pivoting of the lever 32 does not immediately follow, the spring force 38 upon actuation of the shift lever 4 effective, so there is one from the spring 38 mediated actuation force is felt.

The worm gear 26 is advantageously not self-locking, so that the electric motor 16 at a malfunction and increased operating force from the shift lever 4 can be turned off by the pin 34 in contact with an edge of the oblong hole 36 comes. As a result, a circuit is possible even with a malfunction of an electric motor. It is understood that instead of the worm gear 26 Other types of transmissions can be used and that the electric motor 28 can be replaced by other engines, such as hydraulic cylinders.

4 shows an example of a spring characteristic. The spring force F is plotted as a function of the differential travel Δs, ie the difference in rotational angle between the angle of rotation of the lever 32 and the angle of rotation of the toothed segment wheel 22 , the deviation between the desired position and actual position of the switching shaft 14 equivalent. The illustrated linear characteristic provides a directly proportional relationship between the differential path and the shift force felt by the driver. The difference path serves as input for the control unit 18 implemented controller, which increases the power assistance with increased differential path and thus increased operating force on the P component.

In order to give the driver the feeling of a nearly constant shifting force, it is advantageous to provide a preloaded soft elasticity 5 use. This responds to a design force threshold, for example, a force on the shift lever of 20-30 N, on. The one through the slot 36 permissible Leerweg is advantageously smaller than the switching path (for example, 30% of the switching path), so that the driver does not lose the feeling of feedback to the transmission when overpressing the gear end position and the information "gear engaged" is reliably detected by him. The forces F are in 5 thus advantageously about 30 N (relative to the shift lever) and the distance between the coordinate system and A is about 1/3 of the shift travel. The spring characteristics according to 5 can by known per se suitable design of the spring 38 or their replacement can be realized by several springs.

The feather 38 or the springs do not necessarily have as in 2 be arranged shown. They can be located directly in the steering column of the steering column or elsewhere in the transmission from the shift lever 4 to the switching shaft 14 be arranged. 6 shows the arrangement of a preloaded spring 38 in the Schaltbock, whereby the prestressed spring by a clamp 48 is held.

7 shows an arrangement of the spring 38 somewhere in the transmission path between shifter 4 and shift shaft 14 , wherein the relative movement between two transmission members, the deviation between the desired position and actual position of the switching shaft 14 corresponds, from a differential path sensor 48 is detected, for example, instead of the sensor 44 with the control unit 18 connected is.

8th shows one opposite 1 slightly modified embodiment of the power assistance device, wherein a control unit 18 is used, that over the lines 20 and 50 with the sensors 44 and 30 connected to the servo drive 16 over the line 52 operated and other inputs 54 has, which are connected to other sensors or other control devices. Accordingly, the controller includes 18 in a conventional manner, a microprocessor 56 with associated memories 58 , Input / output interfaces, a final stage for the electric motor 16 etc .. Furthermore, a Wählwegsensor 200 be provided, which detects the selection movement of a transmission element, such as the transverse movement of a central shift shaft between each shift gates.

When using a correspondingly constructed control unit 18 and a selector path sensor 200 various functional additions are possible:
The currently engaged gear can be determined.

The switching positions, for example the positions of the end positions and the synchronizers, can be taught in and stored, whereby a constant updating of these positions can take place.

The switching positions can be read during commissioning; Autodiagnosis and service support (via a diagnostic interface) of the power assist device is possible.

The support force can be adapted to the situation, for example, depending on the outside temperature, draft requirements, individual wishes of persons, etc.

The servo assistance rule can be adapted to specific gearbox data.

In the event of a faulty operation, the power assistance can be disabled.

By communicating with information elements, for example optical and / or acoustic displays, driver information and driver warning are possible.

The engaged gear can be detected by software, for example, when non-grinding clutch from the speed of the engine or the transmission input shaft and from the speed of the transmission output shaft or the wheels is closed to the currently engaged gear.

The following is an example of a situation-dependent optimization of a switching sequence explained:
It is characterized by a prestressed elasticity according to 5 went out. In picture 9 is one on the shifter 4 referred force (F) differential path (Δs) characteristic shown. It is also considered that the mechanical transmission links between the shift lever 4 and the transmission have a clearance (range between -S ₀ and + S ₀ ). Furthermore, the basic elasticity, for. B. the Schaltbowdenzugs 8th , Visible (range between S ₀ and S ₁ and beyond S ₂ .

The assist force in synchronizing during a normal shift is set to one in the memory of the controller 18 preset value, which may be gear-dependent, for example. If a quick shift is desired, the driver must press the elastic path of the preloaded spring 38 apply an additional synchronizing force (beyond S ₂ ) to speed up the synchronization process. He can also use the servo drive 16 be supported as in the program flow according to 10 explained.

Is starting from stage 80 in which gear is engaged, in step 82 a switching intent detected, for example, characterized in that the output signal of the shift lever sensor 44 changes, so in stage 84 switched to the zero gear, wherein the engine speed is optionally tracked by means of an electronic throttle. In stage 86 the synchronization is started when the new gear is engaged (S ₁ in 9 ), the electric motor 28 the toothed segment wheel 22 operated with a predetermined force or torque as soon as the bias of the spring 38 is overcome. Will the shifter 4 pushed further in the switching direction, ie the game of the spring 38 used up (reaching S ₂ in 9 ), so increases in level 88 that of the electric motor 28 applied servo force by the amount F _syn2 (Δs). The elasticity of the spring 38 can by the driver by means of the shift lever 4 Be overdriven until the pin 34 in contact with the corresponding end of the slot 36 comes because the sliding sleeve in the transmission still remains in synchronizing locked position. The increase in the characteristic of F _syn2 ( 9 ) is smaller than the spring stiffness of the transmission mechanism, so that the driver always has the feeling of increasing drag as the path increases. As explained above, the differential path ranges from S ₀ to S ₁ and beyond S ₂ in FIG 9 caused by the elasticity, for example, the Schaltbowdenzuges and not by the elasticity of the prestressed spring, is defined by the only force difference characteristic of S ₁ to S ₂ . F _syn2 may be a gang-pending map in which data or force values are stored differently and adjusted as a function of the gear.

In 9 is the second characteristic in addition to that of the electric motor 28 applied additional synchronizing force F _syn2 drawn. This additional synchronizing force is only effective when, in a fast circuit, the elastic play of the preloaded spring 38 is overridden by the driver.

Referring again to 10 gets in stage 90 determined that the synchronization is completed, for example, by the corresponding signal of the sensor 30 , whereupon in step 92 the new gear is on and the gear is in step 94 finished.

In the 11 and 12 the above processes are shown in way (s) - time (t) diagrams. The solid curve indicates the position of the shift lever 4 contrary. The dot-dashed curve indicates the position of the toothed segment wheel 22 or the switching shaft 14 at.

11 shows a normal circuit. The shifter 4 is moved by the driver. The servo drive or electric motor 28 follows due to its inertia somewhat delayed, can in the switching sequence according to 11 the shift lever 4 However, catch up, so that the position of the shift shaft 14 practically corresponds to the setpoint. The driver feels the force of the preloaded spring 38 as an almost constant operating force. While the electric motor 28 the synchronization moves precisely and with a given synchronizing force, the shift lever moves 4 first, until the elastic play is over. In a normal circuit, the driver takes the not yet finished synchronization as blocking the shift lever 4 true (T _syn ) and brings only slightly more force on the shift lever 4 on. After the end of the synchronization both movements run again within the elastic game, that is, with a substantially defined operating force on the shift lever 4 , After reaching the Gangendlage the driver in turn overstates the elasticity of the preloaded spring 38 and has by the existing stop the feedback that the gear is engaged.

12 shows the case of a fast or cracked circuit. The electric motor 28 can the shift lever 4 do not catch up, so that even before reaching the synchronization point, the elasticity of the spring 38 is suppressed. In the locked position, the driver presses the shift lever 4 even stronger, so that the difference between the two way signals increases and the electric motor 28 the additional synchronization force F _{syn2 applies} . The synchronization time T _syn is in 12 therefore much shorter than in 11 ,

In the following, additional functions are explained, with which it is possible to avoid for the transmission or the entire drive train dangerous faulty circuits. In this case, a gear recognition is usually required, ie it must also be the position of the Wählbetätigungsglied 12 be detected, which is possible with the help of an additional displacement sensor, somewhere in the transmission path from the selector lever 4 over the Bowden cable 6 to the selector actuator 12 is arranged.

Similarly, the gears that are prohibited at the respective vehicle speed can be determined.

If according to 13 in stage 100 a shift intent is detected, for example, characterized in that the shift lever 4 is moved, in step 102 the target gear detected, which is to be inserted. This happens because the movement of the shift lever 4 along the selection lane and the further movement is tracked in one of the shift lanes. In stage 104 it is determined whether the target gear is an allowable or permitted gear, can be switched into the without risk to the drive train. If the target gear is permissible, then the normal assistance in step takes place when shifting 106 , If the target gear is not allowed, then according to step 108 deactivated the power assistance, ie the electric motor 28 does not support the switching process.

14 represents a modified flowchart 110 the smallest permissible gear determined. In stage 112 the gear is determined, is switched to the new. In stage 114 it is determined whether the new gear is greater than the permissible gear. If yes, according to step 116 maintain the power assistance, if no, according to step 118 the power assistance ended.

15 shows another flowchart to protect the transmission or drive train against impermissible circuits. In stage 110 In turn, the permissible gears are determined for a circuit. In stage 120 If a maximum permitted synchronization time stored in the memory of the control unit is determined, this is the time duration during which the elasticity of the spring 38 may be suppressed in the synchronizing of the transmission. In stage 122 it is determined whether the permissible synchronization time has been exceeded. If yes, in step 118 the power assistance ended. If no, according to step 116 maintain the power assistance.

The in the 1 to 3 and 8th illustrated servo assist device is advantageously designed so that even in case of failure of the servo drive, a circuit is possible. That's why the worm gear is 26 of the 2 not self-locking. So that the operating force of the shift lever 4 in case of failure of the electric motor 28 is not too high, is in the transmission path between the electric motor 28 and pinion 24 Advantageously, a magnetic coupling (not shown) provided in case of failure of the electric motor 28 opens.

The described power assistance device can be subsequently attached to existing manual circuits in a simple manner, since only the shift lever sensor 44 and the arrangement of 2 with the control unit of 1 must be additionally attached.

It is understood that numerous modifications and additions to the device are possible. For example, the selection movement of the shift lever may be servo-assisted. The device can also be used with linearly moved actuators of the transmission. The described power assist device is advantageously used in conjunction with an automated clutch in order to achieve a particularly high operating comfort.

The use in conjunction with an electric motor-controlled throttle valve actuation, which is controlled by an engine control unit, leads to an advantageous development of the invention.

A power assist apparatus for a transmission having a manual transmission includes a shift lever connected to a shift operating member of a transmission by means of a transmission means for transmitting a shift movement, a shift lever sensor for detecting the movement of the shift lever in the shift direction; a shift sensor for detecting the movement of the shift operating member; a servo drive for moving the switch actuator; a control unit, in which positions of the shift lever are associated with desired positions of the shift operating member and which actuates the servo drive in the event of a deviation of the actual position of the shift operating member from the desired position in the sense of reducing the deviation, wherein the shift lever relative to the shift operating member against the Force of a spring device in its two opposite directions of actuation is movable.

16 shows one opposite 2 modified embodiment of the power assistance. This in 2 formed as a toothed segment gear drive member is in this embodiment as a rotationally fixed to the shift operating member or the shift shaft 14 connected drive lever 60 educated, with an approach 62 in a flask 64 a double-acting piston / cylinder unit 66 intervenes. At each one end face of the piston 64 trained pressure chambers 68 and 70 the piston / cylinder unit 66 are each about a line 72 and 74 with the connections of a reversing pump 76 connected, that of the electric motor designed as a servomotor 16 is drivable in both directions. Depending on the direction of rotation promotes the reversing pump 76 Fluid from the pressure chamber 70 in the pressure room 68 or vice versa, so that the piston 64 according to 16 is moved to the left or right and the drive lever 60 together with the stem 14 twisted.

The function of the described arrangement corresponds to that of 2 with the difference that the worm gear 26 of the 2 through the reversing pump 76 and the double-acting piston / cylinder unit 66 is replaced. As a displacement sensor for detecting the position of the shift shaft 14 used in the embodiment according to 16 for example, a sliding potentiometer 77 with one directly on the piston 64 attached slider. Alternatively, an inductive sensor, a Hall sensor or the like may be provided.

The use of the electro-hydraulic drive for the rotation of the selector shaft 14 has the following advantages:
The electric motor or servomotor 16 and the pump 76 do not have to be in the immediate vicinity of the stem 14 be arranged so that the space freedom is increased.

The pump drive is not self-locking, so that an emergency operation by manual switching in a simple manner is possible.

The system can be produced very economically as a hydraulic system, especially since no valves are needed.

The manual emergency operation in case of failure of the controller or the servomotor can be facilitated by the fact that between the lines 72 and 74 a bypass line 78 is provided, in which a switching valve 79 is arranged, which opens in case of a malfunction in the servo system.

17 shows one in the 1 and 2 shown embodiments of a power assistance device, similar power assistance device 201 with a gear lever 204 Starting from a neutral position in both directions, the gears of a transmission, for example by means of shift forks and disengages, the gears can be arranged on multiple shift gates, via the lever 212 be selected and the selection via the lever 204 characterized in that a to the switching direction substantially vertical movement is carried out, so that for selecting the gears, a so-called H-circuit diagram is formed. Between the shift lever 204 and the lever 212 is a transmission device 206 arranged, which is an articulation of the lever 212 allowed in both directions, for example, a Bowden cable 206 , The movement of the lever 212 and thus the information of the selected shift gate can be detected by a so-called selection sensor, which is provided as a displacement sensor, and the sensor signal to the control unit 252 be directed.

To transfer the switching movement of the shift lever 204 is between this and the shift operating member 222 also a transmission device 208 provided for example as a Bowden cable. The shift operating component 222 is on the drive component 226 arranged and relatively against the action of the spring means 238 rotatable. To accommodate the spring device 238 belonging springs are on both parts 222 . 238 recesses 222a . 226a intended. The relative rotatability may be in a limited range, wherein the limitation may be realized by the block of springs or by stops not shown.

The drive component 226 is by means of a toothed segment disc 226b with a worm wheel or a rack 224 of the servo drive, for example with an electric motor 216 in toothed, so that upon rotation of the worm wheel 224 through the servo drive 216 the toothed segment disc 226b around the shaft 224a is rotatable in both directions. The drive component 226 is rotatable with the shaft 224 connected, with the shaft 224 the shift shaft of the transmission is. At the switching shaft 224 For example, a shift finger (not shown) can move corresponding shift forks, which in turn cause engagement and disengagement of the gears arranged on a shift gate.

One sensor each 250 . 251 For example, a potentiometer or a Hall sensor, is for receiving the respective movement of the switching operation member 222 and on the drive component 226 arranged. The sensors 250 . 251 transmit a signal proportional to the path of the components to a fixed point such as a housing part signal to the control unit 252 , which generates a drive signal after the appropriate calculation taking into account the path signals and optionally further operating parameters and this to the servo drive 216 transmits to its control. The control unit 252 still has a terminal 253 for receiving further operating parameters, such as the position of a brake pedal switch, the signal of the selection sensor 255 a clutch pedal travel sensor, a clutch bearing position sensor and / or temperature sensor, a wheel speed, transmission output speed, a signal of an anti-lock braking device, these input variables in the calculation of the drive signal for adjusting the servo drive assist torque 216 can be considered, as well as a terminal 254 for outputting data and signals, for example to the driver.

The following describes the operation of the power assist device 201 described in more detail.

To shift a gear, the shift lever 204 moved by the driver. As a result, the transmission device 208 against the action of the spring device 238 pulled or pushed, whereby the driver feels a switching resistance and the shift operating member 222 against the action of the spring device 238 is deflected. In this case, detects the shift lever sensor 250 which is either - as shown - on the shift operating member 222 or also, as in 3 shown on the shifter 204 may be directly arranged, a signal of the corresponding Verdrehwegs the Schaltbetätigungsbauteils 222 and transmits it to the controller 252 , whereupon this a drive signal to the servo drive 252 and this outputs the drive component 226 so that drives the shift operating component 222 is tracked and this wave 224a twisted with the applied support torque and initiates the auxiliary power assistance switching process. If a gear is already engaged, it will be disengaged first. The sensor 251 indicates the distance traveled by the drive component and gives it to the control unit 252 further. By evaluating the three sensor signals of the three sensors 250 . 251 . 255 Different switching strategies can be realized.

An exemplary strategy is the regulation of the assist torque of the servo drive 216 as a function of the difference path between the shift operating component 222 and the drive component 226 and, for example, has the following sequence with the states described under positions 1 to 6:

1st transition "gear engaged" to "take out gear"

Exceeds the difference signal x _EH -x _{SH of} the sensors 250 . 251 and the speed ẋ _EH a certain threshold, this is recognized as a "switching intent". This then triggers a change of state after "take out gear". In this state, the neutral position is approached with a setpoint input for x _SH , which corresponds to the neutral position. In order to avoid tearing out of the gear when the clutch pedal is not pressed - ie a load circuit, in addition the position of the clutch release and / or other information can be evaluated, a conclusion to a not yet fully open clutch. If a load circuit is present, the driver receives no shift assistance or the servo drive 216 transmits a moment to the drive component 226 , which is directed against the direction of the switching movement.

2nd transition "exit gear" to "neutral"

Reaches the position of the shift lever 204 the range of the neutral position, the position control is switched off and the state changes to "Neutral". The shift lever is in neutral position.

3. transition from "neutral" to "synchronous approach"

If the difference signal x _EH -x _SH and the velocity ẋ _EH exceed certain thresholds which can assume values other than those described under position 1, as described under position 1, the state changes to "synchronously approaching". In this state, the synchronous position is position-controlled with a setpoint input which corresponds to the synchronous position of the gear to be engaged and in the control unit 252 is stored.

4. Transition "Synchronous start" after "Synchronize"

Will the shifter 204 If the synchronization value is set within a specified tolerance range, the status changes to "Synchronize". In synchronization state can be driven by the synchronization of the transmission with two different strategies. The tolerance range up to the synchronization setpoint can be speed-controlled with a predetermined setpoint speed, ie with the effect of a speed limit, which is independent of the speed of the shift lever. The tolerance range after the synchronization setpoint with a force limit of the servo drive 216 by passing a limited drive signal, which is realized for example by a current control by target specification of a motor current, are passed.

5. Transition "Synchronize" to "Rest position"

Upon reaching the limit of the tolerance ranges is again on a position control with the Gangrhelage switched as a target value. The status changes to "approach to rest".

6. transition "approaching rest position" after "gear engaged"

Will the rest position, the position of the lever 204 with the gear engaged engaged, the condition changes to "gear engaged" and the servo drive 216 will be switched off.

With this procedure, a low-noise and low-wear engagement of a gear can be achieved with appropriate vote.

The 18 shows a power assist device 301 that previously in the 1 . 2 . 17 described embodiments, and to control the power assistance instead of displacement sensors two switches 350 . 351 which, at a rotation x _{EH of} the drive component 326 by a predetermined amount the servo drive on and off again in a return movement. The arrangement of the switches 350 . 351 takes place starting from a neutral position so that in each case a switch is arranged in a switching direction.

In this switching arrangement, the servo drive 316 , For example, as an electric motor, directionally switched on or off. The threshold from which a drive signal from a control unit, the very simple and without microprocessor with memory function, for example as a simple electronic evaluation circuit 352 can be executed, is output by action of the spring device 338 , which may contain a biased energy storage, and the friction of the transmission device as here as a Bowden cable 308 shown - determined. Are during a switching movement x _{HH of} the shift lever 304 overcome these forces moves the elastic lever or Schaltbetätigungsbauteil 322 by the amount x _SH in the direction in which the driver wants to switch. From a position determined by the mechanical arrangement of the elastic lever 322 becomes the one of the switches 350 . 351 , for example, the shift lever 304 or as shown here on the shift operating member 322 - Can be fixed, operated and thus causes a starting of the servo drive with a constant drive signal, for example in the case of an electric motor by means of a constant voltage or a constant current, whereby the shift shaft 324a with a corresponding - not shown - shift fork is rotationally driven. If the tracking of the drive component 326 with a similar speed as the movement of the lever 304 or slower remains the servo drive 316 switched on. With slow movement, the drive component "overtakes" 326 the shift lever 304 That is, the shift is more advanced than the driver by the movement of the shift lever 304 pretends. The spring device 338 is thereby relieved and the corresponding previously activated switch 350 . 351 is switched off again, whereby a switching power assistance is omitted. With increasing movement of the shift lever 304 the switch-on process is repeated again, and slow switching can therefore lead to limit cycles. This can be counteracted to the effect that the speed of the servo drive is set to a typical switching movement and / or on and off threshold of the switch 350 . 351 be subjected to a hysteresis. This solution represents a very simple possibility of switching power assistance, without the control unit and with a very simple control electronics 352 can get along. To optimize are only the drive signal, switch arrangements and hysteresis between on and off threshold of the switch 350 . 351 ,

In 4 is the schematic structure of an embodiment of a power assistance device 401 , which works on the power amplifier principle, shown.

Such a device 401 may be executed deviating from the embodiments equipped with a spring device described above. Central component is a pivotable and axially along the shift gates on a Schaltbetätigungswelle 445 slidably arranged lever 426 that by means of a shift finger 446 positively on a shift fork 447 acting through the sliding sleeve 448 a desired course inserts. To facilitate detection of the end position of the engaged gear is a locking mechanism 449 intended.

On the opposite side of the shift finger is the lever 426 from the transmission facilities 408a . 408b with the stiffnesses 408c . 408d hinged. A force sensor 450 detects the force applied to the lever. The servo drive 416 supports the driver by means of a movement of the manual lever 404 initiated switching request. The displacement sensor 451 detects the deflection of the shift lever 404 , A control unit 452 , which in turn can consist of an evaluation electronics in a simple manner, processes the sensor signals and outputs a drive signal to the servo drive.

The switching sequence is proportional to that on the lever 426 in the area of the sensor 450 acting force. Taking into account the characteristic values, for example the stiffnesses 408c . 408d , the efficiencies and levers of the transmission facilities 408a . 408b A condition can be formulated according to which the applied forces of the servo drive and the switching forces in the must be proportionate to each other, so that they are proportional to the forces that must be expended for the insertion of the aisle. For a given actuating force and torque of the servo drive 416 can depend on the shift lever deflection s and the lever 426 on the force sensor 450 measured force F a relationship for the drive signal AS are determined according to: AS = f (F, dF / ds, d ² F / ds ² )

The drive signal AS is therefore dependent on the force F and its two derivatives dF / ds and d ² F / ds ² . For an electric motor as a servo drive can be controlled by the current or the operating voltage. A derived from the equations of motion and the electrical parameters dependence for the operating _current I _EMotor or the operating voltage U _EMotor using the signals F _switching , X _switching the sensors 450 . 451 can as a drive signal for serving as a servo drive electric motor 416 are implemented in the controller unit according to the following equations, wherein the constants c ₁ -c _{5 are} system-specific constants and minor portions are in parentheses.

The control of the servo drive via the current is simpler and less dependent on the temperature. The force sensor 451 For example, it may be a displacement sensor that performs a relative displacement measurement in an elastically deformable component, or a pressure sensor that detects a return to the effective force in conjunction with a hydraulic or elastomeric element. Furthermore, pressure elements, such as piezo elements for displaying the pressure dependent on the force can be used as force sensors in the transmission devices.

The power assist device with on the shift operation shaft 445 rotatably mounted lever 426 is to be regarded as an exemplary embodiment. It is understood that a power-proportional power assistance device can be applied to any other switching mechanism of a manual transmission. In addition, angles and paths or forces and moments should be considered as equivalent quantities.

Based on 20 the advantages of using a hysteresis of the switching thresholds s ₁ , s ₂ in the use of an embodiment of a power assistance device 301 in 18 explained in more detail with a control of the servo drive by switches.

The 20 shows a diagram in which the supply voltage U of the servo drive 316 ( 18 ) when using an electric motor against the displacement x of the shift operating member 326 ( 18 ) is applied. The solid lines show the voltage curve without and the dashed lines when using a PT ₁ filter with arbitrarily shown in this diagram time constant T ₁ , T ₂ , T ₃ , T ₄ , which are assigned to their index according to the threshold values and for each threshold can assume different values, whereby in each case adapted to the corresponding course of the switching path operating voltage U _{B of} the servo drive, which adjusts in time sequence depending on the applied filter, can take place. The thresholds s ₁ , s ₂ are the switch 350 and the thresholds s ₃ , s ₄ the switch 351 ( 18 ), wherein upon reaching the thresholds s ₁ , s _3, the switches 350 . 351 the servo drive 316 activate and in a reduction of the path x in the direction of neutral position, which does not necessarily have to be at the zero point of the switching path, and the achievement of the thresholds s ₂ , s ₄ off again. Between the switch-on thresholds s ₁ , s ₃ and the switch-off thresholds s ₂ , s ₄ , the hysteresis is provided in order to minimize limit cycles. The use of filters can improve the response of the servo drive and dampen jerky shifts, especially with very slow driver shifts.

21 shows a diagram for wiring a servo drive with a drive signal AS in the region of the neutral position NS as a function of the position of the lever x _SH with the waypoints s ₁ , s ₂ s ₃ , s ₄ - not to be confused with the thresholds s ₁ , s _2nd s ₃ , s ₄ of 20 - to improve detection of the neutral position.

The detection of the neutral position can be made possible in addition to the possibility of using a mechanical detent for the driver on the set by the drive signal AS amount of the assist torque of the servo drive in the region of the neutral position NS. For this purpose, the 100% value of the drive signal AS determined, for example, by further algorithms as a function of the operating parameters chosen here is configured as a falling drive signal AS when the waypoints s ₁ , s _{4 are} falling from the respective side to the waypoint s ₃ or s ₄ . that - as in 21 shown - can be linear, but can also take any advantageous form. In the area between the waypoints s ₂ and s ₃ around the zero position NS, the drive signal AS and thus the assist torque is lowered to a value independent of the distance x%, for example 70> x ≥ 0, in which case the support is completely omitted. The driver has a shift feel, as he knows it from unsupported circuits ago and can find the neutral position better.

In 22 is a diagram for further explanation of the drive signal as the operating voltage U for serving as a servo drive electric motor as a function of the differential travel x _EH -x _SH between the drive member (for example 226 in 17 ) and the shift operating member (for example 222 in 17 ). For small difference signals between ds ₁ and ds ₂ , this may, for example, the range of action of the spring means (for example 238 in 17 ), no voltage U is applied. If the differential path x _EH -x _SH greater, depending on the switching direction and thus of the direction of rotation of the electric motor an increasing or negative voltage decreasing voltage U is impressed, the - preferably and the diagram accordingly - linearly with the slopes K ₁ for the negative and K _{2 runs} for the positive branch. Gradients K ₁ and K ₂ are systemic and will be adjusted accordingly. Upon reaching the maximum operating voltage U _{max of} the electric motor at the points ds ₃ and ds ₄ , the voltage is limited.

23 shows as an alternative to the in 13 shown embodiment, another embodiment of a flowchart of a regularly executed in a predetermined time cycle routine for detecting a shift intention, which can also be combined with each other.

After the start 500 will be at the junction 501 checked whether the neutral position NS is set. If this is not set, that is, it is a gear engaged, and is in the branch 502 no gear change signal GW, for example by a corresponding signal of a displacement sensor, is indicated in 503 a shift intention signal SA is set to "0" and in 504 the routine ends.

If a gear change signal in 502 is detected, in the branches 511 . 512 determines which gear G is engaged and whether the signals x _{1, WH, SH} , x _{2, WH, SH} determined from the selector sensor WH and the shift lever sensor _{SH are} plausible. If they are not plausible and do not yield any realizable switching process, the switching intention signal will be in the field 503 is set to " 0 " and the routine terminates, a logical shift occurs, the shift intention signal SA in the field 513 is set to "1" and the routine is ended.

If the neutral position NS is set, is in the Verzeigung 505 checked whether the conditions engine speed n _mot greater than or equal to the idle speed n _LL and the wheel speed n _{wheel is} less than a predetermined threshold n _threshold , for example 0.1 / sec, that is, if the engine is running and the vehicle is in motion. If the condition is not met, will be in 503 SA = "0" is set and the routine is ended. If the condition is met, it will be based on the branch 506 checked by analysis of the operating parameters, such as the shift lever sensor SH and the displacement sensor WH, whether they meet a set c ₁ of thresholds. From this it is deduced whether the path is taken in a positive or negative direction. From this, from the neutral position, the switching direction is derived to the rear, in the field 507 is saved as the "back" condition. in The Field 508 a shift intention signal SA is set to "1" and the routine is ended.

If the conditions for a shift direction to the rear are not met, take place in the branch 509 the check for a shift request forward with evaluation of the sensors WH, SH with respect to threshold values to be complied with according to the threshold value c ₂ . If these conditions are also not met, there is no intent to shift and in the field 503 the shift intention signal is set to "0" and in 504 the routine ends. Be the conditions in the branch 509 is fulfilled in the field 510 the switching direction "front" filed and in field 508 the shift intention signal is set to "1" and the routine in 504 completed. The switching intent signal generates in further program routines, if it is set to "1", a switching operation in dependence on those in the fields 507 . 510 stored information on the switching direction "front" or "rear".

In 24 is a possible routine for detecting the switching state shown as a flowchart. The sequence of the routine is advantageously carried out periodically at short intervals, wherein the time interval compared to the rate of change of the switching states should be small. The sequences of the switching sequence are controlled in further routines, which are approached by the control signal "state" formed in this routine.

After the start 550 the routine gets in the branch 551 queried whether the status signal "meshing", that is, by means of the servo drive to engage a gear is up-to-date. If the state is up to date, it will be in the branch 552 queried whether a gear is engaged, that is, whether the end position of the Einspurens is reached, which can be determined for example via a threshold value of the switching sensor. If not, it will be in the field 553 receive the status signal "Einspuren" and the routine ends. When the final position is reached, it will be in field 554 the state signal "KeinGW", ie no active gear change active, generates and terminates the routine.

If the status signal "meshing in" is not active, the branch is routed 551 to the junction 555 Next, in which it is queried whether it is being synchronized "Synchronize". If this is the case will be in the branch 556 determined, for example, via the evaluation of the power consumption of the electric motor over time or via the path signal of the Switching sensors, the specific setpoints of the synchronization are assigned to whether the synchronization path is traversed, ie "SyncBereich leave" applies. When the synchronization is passed through, it will be in the field 553 resetting the status signal "meshing" and terminating the routine, if it is not completed, the status signal in the field 557 Preserve "Sync" and exit the routine.

Is the status signal at the branch 558 "Syncstart" is approached from the neutral position to the synchronization position. When the area is reached, it is in the junction 559 to the field 557 forwarded and set the status signal to "Synchronize and then exit the routine. If the synchronization range has not yet been reached, the status signal in the field 560 get and finish the routine.

At the status signal "Neutral" in the branch 561 is based on a switching intention, for example according to the routines in 13 and or 23 checked, the shift intention signal is then in the branch 562 used for the evaluation. If there is a switching intent, the status signal "Syncstart" is displayed in the field 560 activated for processing the corresponding subroutine. Located in 562 no intent to switch is in box 564 maintaining the status signal "neutral", which means that the transmission is in neutral position.

Lies at the junction 563 the status signal "GangHeraus" on, the servo drive is about to disengage a gear. In the branch 565 It is checked whether the neutral position has already been reached. If this is the case, the status signal in the field 564 set to "neutral", otherwise the status signal in the field 566 maintained and the routine ended.

When in the branch 567 the condition signal "KeinGW" is present, that is, for example, driven at an engaged gear, takes place in a loop on the branch 568 the query, if there is a switching intent. If there is a shift intent, the status signal "GangHeraus" in the field 566 generated and the routine ended. Otherwise, the branch heads 568 to the junction 569 further.

The branch 569 sets the status signal in dependence on whether the shift operating device is in the neutral range in the field 570 to "Neutral" or if the condition does not apply in the field 571 to "KeinGW", ie to maintain the engaged gear.

This in 25 The flowchart shown is an example of the switching sequence of a servo assistance device 24 set state signals are evaluated.

The start 572 the routine branches into the branch 573 over, which in the case of a Einspurvorgangs in the field 574 executes a routine for starting the Gangruhelage, wherein the starting position controlled, that is, in response to displacement sensors, such as the shift sensor occurs. When the rest is at rest and the gear is engaged, the routine is ended.

If the status signal "Synchronize" is active, it will be in the branch 575 to the subroutine 576 in which the operating voltage U for the servo drive is reduced in order to reduce the force F or the assisting torque, in order to prevent damage to the synchronizing device and increased switching noises. Thereafter, the routine is ended.

If the status signal "Sync Startup" is active, it will be out of the branch 577 with in 576 reduced moment of support in the field 578 approached the synchronization area and then terminated the routine.

In the state "Neutral" is out of the branch 579 the field 580 controlled, which shuts off the operating voltage of the servo drive.

In the state "GangHeraus" is out of the branch 81 out the field 582 controlled, which takes in response to a displacement sensor, such as the circuit sensor, the gear and moves to the neutral position and then terminates the routine.

The status signal "NoGW" activates via the branch 583 a loop back into the branch branch through which, if a status signal is denied, the sequence takes place and finally in the field 584 the servo drive is deactivated, for example, by switching off the operating voltage U _{EM of} the electric motor.

The flowchart of the state recognition in 24 in conjunction with the. State flow in 25 is previously described so that corresponding state signals are set and then the routine is terminated and in the subsequent state sequence corresponding subroutines for selectively processing the switching sequence are called. It goes without saying that a sequence can also be carried out in such a way that correspondingly named subroutines can be called immediately after the status signal has been set and, after passing through the routine, the state recognition routine is continued at the same point.

26 FIG. 12 is a flowchart of a routine that makes the activation of the servo drive dependent on the presence of a driver. After the start 600 the routine gets in the branch 601 from the condition Ind ₁ = 1 determined whether a driver is sitting in the vehicle. For example, Ind ₁ can be set to "1" if at least one or more of the following conditions are met, that is, the following conditions can be linked by "and" or "or" linking: Starter is activated, Brake is actuated, accelerator pedal is actuated, clutch is actuated, steering movements, belt is in the lock, engine speed is significantly higher than idle speed. If the answer applies to the linking of the elements, the field appears 602 activates the driver signal, which is hot set to "1". in The Field 603 Subsequently, a timestamp t is set, which can be in the range 0 <t <15 s. in The Field 604 is carried out depending on the presence of the driver switching power assistance. Thereafter, the routine intended for periodic operation is terminated and called again after a predetermined time has elapsed.

If an indication Ind ₁ = "1" is not given, it will be in the branch 605 queried whether the timestamp is t> 0, whereby it can be determined whether the driver is only inactive for a certain time or has left the vehicle and in the case of fulfillment of the condition in box 606 diminished by an amount .DELTA.t. Below is in the branch 607 determines whether n _wheel > 0 or a small value, whereby a movement of the vehicle is detected and the process with the field for power assistance 604 will continue. If there is no movement of the vehicle, it will be in the junction 608 the combination of a second record for detecting whether the driver is present Ind ₂ , for example consisting of a door opening signal, a parking brake signal and / or the time mark t> 0. If the combination of conditions is met, so Ind ₂ = 0, can on it be concluded that no driver (more) sits in the vehicle and the driver detection signal is in the field 609 set to "0" and the routine ends. If the condition Ind ₂ = 0 is not fulfilled, the sequence with the field becomes 604 continued and the switching power continues to be supported.

The 27 FIG. 12 is a flowchart of a routine for preventing a load circuit, wherein the assistance of the switching movement decreases with increasing degree of the load circuit. The load circuit is detected by a sensor, for example, a path of the release bearing receiving displacement sensor, and a load circuit-dependent map with a maximum for the corresponding load switching state drive signal AS _S is stored in the memory of the control unit.

After the start 610 the routine will be in the field 611 a current drive signal AS _L for the servo drive, which is dependent on the degree of the load circuit formed. Is in the branch 612 the drive signal AS greater than the permitted under load switching conditions drive signal AS _L , this is reduced to the maximum under load switching conditions allowable drive signal AS _L and the driver feels a greater resistance during the switching process. If no load circuit is present, the drive signal AS remains unchanged.

Another embodiment for preventing or warning of a load circuit is in the flowchart of 29 shown.

Here, the shift intention signal SchAbs is delayed so long, that is, it is detected in other routines that rely on this signal, no shift intention and therefore switching assistance initiated until the load switching conditions are canceled, the load switching routine is traversed at short intervals.

This will be done after the start 620 the routine in the branch 621 determines the no load of the transmission, for example, by evaluating a clutch sensor and / or -schalter, Ausrücklagersensors, Kupplungspedalwegsensors, engine torque determination and / or the like. If the gearbox is free of load, will be in the junction 622 checked whether a shift intent (SchAbs = "1" or Schabs_alt = "1") is present or existed, where SchAbs_alt = "1" means that earlier one by the branch 621 suppressed switching intent existed. If one of the two sizes is set to "1", then after in the field 653 SchAbs = "1" and SchAbs_alt = "0" has been set in the shift intent routine, the shift intention to be processed and the routine is terminated.

If the transmission is not relieved, so there is a load circuit, is by branching 621 into the branch 624 initiated where is branched in response to the switching intention signal and wherein in the presence of a switching intention in the field 621 the switching intent signal is renamed SchAbs_alt and set to "1" in order not to lose the information about the switching intent. Then, the shift intention signal SchAbs becomes the field 626 is set to "0", so that a switching intention in the routines that rely on the switching intention signal is not recognized and a switching assist is omitted until after the periodically iterating through the routine at the branch 621 the load freedom of the transmission is determined.

When using a servo assistance device, in which the servo torque of the servo drive is designed so that the manual force to be applied by the driver is proportional to the Shifting force on the switching device or proportional to the switching torque on the shift shaft, advantageously a routine for no load of the transmission can be omitted, since in such control of the servo drive, the driver has the shift feel of a conventional, unsupported transmission and therefore - if desired - the responsibility of Load circuits in the usual way in the driver's hand lies. It is understood that in such a control routines for power switching prevention can also be used when a standalone solution is desired.

30 shows by way of example a flowchart of a routine for automatic removal of an engaged gear in appropriate situations, such as to avoid the stalling of the engine or in abrupt braking maneuvers. This will be done after the start 630 the routine in the field 631 the speed of the engine n _motor detected and in the field 632 a speed change dn _engine calculated in the time interval dt. In the branch 633 is exemplified as a criterion for a threat of engine stalling below a threshold n _threshold by the engine speed n _engine tested. The threshold is preferably 100 to 300 rev / min below the typical idle speed. As a criterion for an abrupt braking maneuver the time change - namely the decrease - the engine speed dn _motor / dt against a threshold dn _threshold / dt can be checked, in which case a speed decrease between -2000 to -3000 U / min be advantageous as a threshold dn _threshold can. To secure the result, for example, the operation of the brake switch or an available anti-lock signal can be included in the decision. If there is an appropriate situation justifying the removal of the gang, the gangway will be in the field 634 It should be noted in the position-controlled manner, and it should be noted in the further routines that it can be a load circuit. Following or if the conditions after branching 633 not present, the routine is in 636 finished, This routine is also run regularly at short intervals.

In the 31 shown routine shows a possibility of selectively supporting certain gears as a function of the driving situation, here for starting the vehicle from the state. It should be usable only for starting suitable gears, such as the first two gears with the smallest ratio 1, 2 and reverse R.

These will be after the start 640 the routine in the field 641 important parameters for the switching function, such as the signals of the shift lever sensor x _SH , the selection sensor x _WH , the shift sensor x _SH , the engine speed n _motor and the wheel speed n _wheel detected. The detection step 641 follows a scaling step 642 , In the branch 643 It is checked whether the engine idling speed n _LL or more, that is, whether it is running and whether the wheels are moving, that is, whether the vehicle is rolling. The threshold n _threshold for the wheel speed may also be designed so that a slight rollers is still regarded as a starting situation in the prior. Stands through the "and" links 643 determines that the vehicle is in the starting state is in field 645 set a control character or flag, which in the shift sequence routines only the starting gears, such as gear 1, 2, R. If another driving situation detected, are formed by forming a control signal in the field 644 all gears supported. After the fields 644 . 645 will the routine in 646 ended and regularly called again at short intervals.

Another safety aspect is the release of the starter for the engine depending on the switching state of the transmission. This in 32 The flowchart shown shows a routine for generating a control signal for preventing the starter release when a gear is engaged at the beginning of the starter operation.

This is the routine with the field 650 started and in the field 651 the request for the request, for example, about the starter switch and the shift lever position x _SH detected. After scaling the sensor signals in 652 will be in the branch 653 decide if there is a request for a reason. If this is before, will be in the branch 654 checked whether the neutral position of the transmission is set, for which purpose the shift lever sensor signal can be used for the evaluation. At neutral position is in field 655 set the control signal to the starter release, whereby the starter can be controlled in a corresponding routine. Then the routine is ended. In cases where there is no reason to request or the transmission is not in neutral, the field will show 656 the control signal for releasing the starter is set to "0", that is, in the corresponding control routine, the request for starting is suppressed, and the engine can not be operated before shifting to the neutral position.

It will be appreciated that in the above-described routine, if appropriate information is available, for example, about a clutch sensor, clutch switch, release path sensor or the like, the position of the clutch may be included so that in the branch 654 For example, via a "or" link the possibility is opened to set the control signal for releasing the starter even with the gear engaged and the clutch depressed and thus also to start the engine in this situation.

Claims (93)

A manual override servo-assisting apparatus including a shift lever connected to a shift operating member of a gearbox by a transmission means for transmitting a shift, a servo drive for moving the shift actuator, means for detecting the movement of the shift lever in the shift direction, and a control device for controlling the shift lever Servo drive and in that the shift lever is movable relative to the shift operating member against the force of a spring means in its two opposite directions of actuation, wherein the shift actuator is a shift shaft of the transmission, which is rotatably connected to a drive member which is rotationally driven by a servo drive, and the transmission means a mounted on the drive member lever with means for limiting the relative rotatability between the lever and the drive member au fweist and wherein between the lever and the drive member at least one energy storage acts such that the lever when it is not acted upon by the shift lever forth with a force in an equilibrium position of the relative rotation range. Power assist device according to claim 1, characterized in that an assist torque of the servo drive in response to at least one force and a displacement sensor is set. Servo assisting device according to claim 1 or 2, with a control device in which positions of the shift lever are assigned to target positions of the shift operating member and actuated at a deviation of the actual position of the shift operating member from the desired position, the servo drive in the sense of reducing the deviation. A power assist device according to any one of the preceding claims, wherein the movability of the shift lever relative to the shift operating member is limited by stops. A power assist device according to any one of the preceding claims, wherein the means for detecting the movement of the shift lever is a shift lever sensor or a switch. A power assist device according to any one of the preceding claims, wherein a circuit sensor or a switch is provided for detecting the movement of the shift operating member. A power assist device according to any one of the preceding claims, wherein the transmission means comprises a lever coaxially mounted with the shift shaft, formed with a pin engaging in a slot of the drive member, having limited relative rotatability between the lever and the drive member, and wherein between Lever and the drive member at least one spring acts such that the pin is in the state in which the lever is not acted upon by the shift lever forth with a force in a central region of the elongated hole. A power assist device according to any one of the preceding claims, wherein the drive member is a toothed segment wheel which is rotationally driven by a gear, such as worm gear, from the servo drive configured as a servo motor, such as an electric motor. Servo support device according to one of the preceding claims, wherein the drive member is driven by a movable in two opposite directions piston a piston / cylinder unit with two pressure chambers, which pressure chambers via one line is connected to one of two of a driven by the servo drive reversing pump. A power assist device according to any one of the preceding claims, wherein the leads are interconnected via a bypass line in which a valve opening in the event of malfunction of the power assist device is arranged. A power assist device according to any one of the preceding claims, wherein the spring means has a linear characteristic. A power assist device according to any one of the preceding claims, wherein the spring means has a pre-stressed, soft characteristic. Power assist device according to one of the preceding claims, characterized in that the control device for controlling the servo drive is formed of at least two switches, which in both directions within the limited, relative rotation range between the lever and the drive member at a deviating from the equilibrium position by a differential way waypoint are arranged and when exceeding the differential travel in the direction of the switching movement the servo drive after exceeding Activate a switching threshold and deactivate it when falling below the switching threshold. A power assist device according to any one of the preceding claims, wherein the switching threshold for activating the servo drive is provided at larger difference paths than the switching threshold for deactivating the servo drive. Power assist device according to one of the preceding claims, wherein starting from a neutral position, the differential paths in both directions of the switching movement are different. Power assistance device according to one of the preceding claims, wherein in the switching device, a catch for highlighting the neutral position is provided. Power assistance device according to one of the preceding claims, wherein the detent on the shift lever, the shift shaft or another component connected to the switching device is arranged. Power assistance device according to one of the preceding claims, wherein in the region of the neutral position of the shift lever, the assist torque of the servo drive is lowered. Servo support device according to one of the preceding claims, wherein after detecting a shift intent of the gear engaged automatically disengaged from the servo drive and the drive member is brought into neutral position. A power assist device according to any one of the preceding claims, wherein the servo drive is an electric motor and an assist torque is set via the voltage applied thereto or the current flowing therethrough. Power assist device according to one of the preceding claims, wherein the voltage applied to the electric motor in the range of half maximum operating voltage of the electric motor. A power assist device according to any one of the preceding claims, wherein the voltage applied to the electric motor is filtered by a first order low pass filter. A power assist device according to any one of the preceding claims, wherein at least two displacement sensors detect the travel of the shift lever and the shift operating member to be traveled during the shift. A power assist device according to any one of the preceding claims, wherein the shift sensor or the shift lever sensor is formed as a sensor detecting the travel received by the spring means. Servo support device according to one of the preceding claims, wherein this is provided for a transmission with a plurality of shift gates and the selection of the shift gates is done manually via a second transmission device. Power assist device according to one of the preceding claims, characterized in that a sensor, such as selector sensor, is provided, which detects the selection of the shift gate. A power assist device according to any one of the preceding claims, wherein the assist torque of the servo drive is adjusted in response to the path or angle of rotation of the drive member relative to the shift operating member during the shift operation. A power assist device according to any one of the preceding claims, wherein the assist torque of the servo drive is adjusted in response to the signal of the shift sensor during the shift operation. Servo support device according to one of the preceding claims, wherein the assist torque of the servo drive in dependence of a from the path or angle of rotation of the mounted on the drive member lever of the transmission device minus the path or angle of rotation of the drive component determined differential travel is set during the switching operation. Power assist device according to one of the preceding claims, wherein the assist torque of the servo drive in response to a determined from the path or angle of rotation of the shift lever minus the path or angle of rotation of the drive component differential travel is set during the switching operation. A power assist apparatus according to any one of the preceding claims, wherein the assist torque of the servo drive is set in accordance with a difference signal formed from the signal of the shift lever sensor minus the signal of the shift sensor during the shift operation. A power assist device according to any one of the preceding claims, wherein the assist torque of the servo drive is adjusted in response to the signal of the selection sensor. A power assist device according to any one of the preceding claims, wherein the assist torque of the servo drive is adjusted depending on the speed with which the shift lever is moved. A power assist device according to any one of the preceding claims, wherein the speed of the manual shift lever is determined from the travel of the shift lever over time and the travel from the sensor signal of the shift lever sensor. A power assist device according to any one of the preceding claims, wherein the sensor signal is applied with a filter for eliminating uniform motions. Servo support device according to one of the preceding claims, wherein when a predetermined speed threshold of the shift lever is exceeded, a shift intent detected and the servo drive is activated. Power assist device according to one of the preceding claims, wherein when a predetermined value of a travel of the shift lever is exceeded, a shift intention is detected and the servo drive is activated. A power assist device according to any one of the preceding claims, wherein the controller includes a microprocessor with associated memories and signal inputs and outputs. A power assist device according to any one of the preceding claims, wherein the assist torque is set in dependence on an operating temperature. Power assistance device according to one of the preceding claims, wherein the operating temperature is determined at least from a transmission oil, engine oil and / or cooling water temperature or a combination thereof. Servo support device according to one of the preceding claims, wherein the determined temperatures are stored as a temperature map in a memory. Servo assisting device according to one of the preceding claims, wherein the servo drive outputs an additional assisting torque as offset from a temperature threshold value to lower temperatures. Servo assisting device according to one of the preceding claims, wherein the drive signal for the servo drive is subjected to a temperature-dependent factor. Power assist device according to one of the preceding claims, wherein the drive signal supplied by the control device to the servo drive depends on operating parameters. Servo support device according to one of the preceding claims, wherein the sensor signals and / or determined differential paths are corrected as a function of temperature, wear conditions and / or depending on the selected gear. Servo assisting device according to one of the preceding claims, wherein assigned during commissioning, the desired positions of the shift lever corresponding gears and / or a neutral position of a setting without gear engaged and stored in a memory. A power assist device according to any one of the preceding claims, wherein the desired positions for the assigned gears correspond to an H-circuit diagram. Servo assisting device according to one of the preceding claims, wherein each of the one or two gearshift positions which can be inserted in the forward and backward directions in the neutral position is assigned an average desired position and stored in a memory. Servo assisting device according to one of the preceding claims, wherein given start-up certain path positions of the shift lever synchronization positions for the individual gears or gear groups are assigned and stored in a memory. A power assist device according to any one of the preceding claims, wherein the servo drive is operated in response to the synchronizing positions. Servo support device according to one of the preceding claims, wherein data is stored redundantly in the memory. A power assist device according to any one of the preceding claims, wherein the data is updated over the entire operating time of the power assist device. A power assist device according to any one of the preceding claims, wherein the servo drive can only be activated when a driver is seated in the vehicle. Power assistance device according to one of the preceding claims, wherein a Presence of the driver by means of a weight sensor and / or switch is detected in the driver's seat. A power assist device according to one of the preceding claims, wherein a starter for starting an internal combustion engine for driving a vehicle with the power assistance device is not operated until the neutral position is set. Power assist device according to one of the preceding claims, wherein the neutral position is detected by means of the shift lever sensor. Servo-assisting device according to one of the preceding claims, wherein the starter can be actuated only when a arranged in the power flow between the engine and transmission clutch is completely disengaged. A power assist device according to any one of the preceding claims, wherein the disengaged state of the clutch is indicated by means of a clutch switch. Power assistance device according to one of the preceding claims, wherein a necessary operating force of the shift lever is manually adjustable. A power assist device according to any one of the preceding claims, wherein the actuation force is adjustable in the range between 10 N and 100 N. Servo assist device according to one of the preceding claims, wherein the drive signal for the servo drive is acted upon by a factor determined by means of a potentiometer, a tap changer or the like predetermined value. A power assist device according to any one of the preceding claims, wherein the servo drive applies an additional force to the shift operating member when the spring means is over-pressurized. A power assist device according to any one of the preceding claims, wherein the controller interrupts the activation of the servo drive when, during a shift operation, the spring means is over-pressurized for more than a predetermined period of time. A power assist device as claimed in any one of the preceding claims, wherein the servo drive is deactivated upon an improper gear shift. A power assist apparatus according to any one of the preceding claims, wherein the controller determines an engaged gear with non-slip clutch from the engine speed and the transmission output speed. Servo assistance device according to one of the preceding claims, wherein the control device of the vehicle speed dependent, impermissible gears are stored. Power assistance device according to one of the preceding claims, wherein in a shift request in an impermissible gear, the servo drive is not activated. Servo support device according to one of the preceding claims, wherein is activated in a shift request in an impermissible passage of the servo drive against the switching direction. Power assistance device according to one of the preceding claims, wherein powershift operations that are performed when the clutch is closed or not fully open, are not supported by the servo drive or acted upon by an opposite assist torque. Servo support device according to one of the preceding claims, wherein a load switching operation is detected by evaluating at least one sensor or switching signal following operating parameters: engine torque, throttle angle, accelerator pedal angle, Ausrücklagerweg, clutch pedal travel, idle position, clutch position. Servo assisting device according to one of the preceding claims, wherein in the presence of a load circuit, the switching process is delayed until the load switching conditions are canceled. A power assist device according to any one of the preceding claims, wherein the assist torque is increased with decreasing degree of the load circuit in response to a signal representing the degree of the load circuit. Servo support device according to one of the preceding claims, wherein as starting gears from the state only with respect to the translation into the slow the first two gears and one reverse gear are allowed. Power assist device according to one of the preceding claims, wherein the servo drive and / or the power transmission between the servo drive and the shift operating member such is formed so that the switching actuator is actuated by the shift lever in case of failure of the servo drive. Power assist device according to one of the preceding claims, wherein in the power transmission between the shift operating member and the servo drive, a clutch opening in case of failure of the servo drive is arranged. Servo support device according to one of the preceding claims, wherein the functionality of sensors, in particular shift lever sensor, circuit sensor and / or dial sensor is checked by means of plausibility checks. A power assist device according to any one of the preceding claims, wherein the path lengths of the shift sensor and the shift lever sensor are compared with each other in consideration of the lever ratios for determining the plausibility of the sensors. A power assist device according to any one of the preceding claims, wherein the signal of the selection sensor is compared with the engine speed and / or with the wheel speed and / or the speed of the speed taking into account the gear ratios for determining the plausibility of the engaged gear and / or the rotational speeds. Servo assist device according to one of the preceding claims, wherein during the activation of the servo drive, a check is made for changing a path length to be effected by the servo drive. Power assistance device according to one of the preceding claims, wherein in case of failure of the shift lever sensor, a substitute value from the movement of the circuit sensor taking into account the lever ratios acting between the two sensors and optionally the stiffness of the spring means is formed. A power assist device according to any one of the preceding claims, wherein in case of failure of the shift sensor, a substitute value is formed from the movement of the shift lever sensor taking into account the lever ratios effective between the two sensors and optionally the stiffness of the spring means. Power assistance device according to one of the preceding claims, wherein a defect in the transmission device is detected by plausibility check of the two output from the circuit sensor and shift lever sensor signals. Servo support device according to one of the preceding claims, wherein in case of a defect of the transmission device, the shift lever sensor is used as a setpoint specification and the servo drive applies the entire torque required for the circuit. A power assist device according to any one of the preceding claims, wherein the driver is alerted to defects. Power assistance device according to one of the preceding claims, wherein the driver is informed of a necessary workshop visit. Servo support device according to one of the preceding claims, wherein the driver of the driving style is appropriate, in particular with regard to the saving of energy, compared to the inserted possibly more favorable gear is proposed. Power assistance device according to one of the preceding claims, wherein the power assistance device automatically disengages an engaged gear in selected driving situations and switches to neutral position. Power assistance device according to one of the preceding claims, wherein the selected driving situation is given in threatening stalling of the internal combustion engine. Power assistance device according to one of the preceding claims, wherein the selected driving situation is given during strong braking operations of the vehicle. Power assistance device according to one of the preceding claims, wherein the selected driving situation is given in response to an anti-lock device. A power assist device according to any one of the preceding claims, wherein the device further comprises an electronically controlled fuel supply, such as throttle control or injector, which is controlled by another controller and actuated, for example, by an electric motor. A power assist device according to any one of the preceding claims, wherein the assist torque of the servo drive is set in response to at least one force sensor acting on the drive member and a travel sensor receiving the travel of the shift lever. A power assist device according to any one of the preceding claims, wherein the assist torque of the servo drive is set in proportion to the operating force applied to the shift lever.

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