Actuating device for automatically actuating a manual transmission

An actuating device for automatically actuating a manual transmission, which has an output element that can be driven in a first direction by a first drive and in a second direction by a second drive. Each drive is assigned a sensor which displays an actuating movement and detects a movement if the output element and whose signals are fed to a control device. In the case of a movement of the output element the sensors output to the control device signals assigned to this movement, the signals specifying the respective magnitude of the movement. The control device uses the signals with reference to an arbitrary prescribable reference point to determine the actual position of the output element and relate the actual position to a desired position of the output element which is to be approached, with the perception that the desired position has not been reached after termination of an actuating movement, or the absence of the signals which indicate the actuating movement causing the control device to activate an emergency function.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to an actuating device for automatically actuating a 
manual transmission. 
2. Discussion of the Prior Art 
German reference DE 43 09 027 A1 has already disclosed an actuating 
cylinder for actuating a shifting shaft. The actuating cylinder has a 
first hydraulic cylinder and a second hydraulic cylinder. The first 
hydraulic cylinder is a double-acting cylinder which acts on an actuating 
piston to which the shifting shaft is firmly connected. The shifting shaft 
can be driven in a translatory fashion by the first hydraulic cylinder. 
The second hydraulic cylinder is connected via a driver element, which is 
connected in turn to the actuating piston in a fixed but axially 
displaceable fashion. A translatory movement of the piston of the second 
hydraulic cylinder, which is connected to the driver element via spiral 
teeth, is converted by the driver element into a rotary movement. The 
shifting shaft can therefore be driven in a rotary fashion by the second 
hydraulic cylinder. Given an appropriate drive, the shifting shaft can be 
automatically actuated by the actuating cylinder. Sensors are provided for 
detecting the paths of the actuating movements which can be initiated by 
the hydraulic cylinders. For example, it is possible to provide linear 
potentiometers as sensors. It is preferable to use sensors which operate 
without contact and which comprise a permanent annular magnet attached to 
the actuating piston, and a coil element, attached to the cylindrical 
outer wall of the housing, with primary and secondary windings. The 
absolute position of the shifting shaft is detected by the sensors. It is 
disadvantageous that because of the sliding-action contact the linear 
potentiometers have a short service life, and that the contactless 
magnetic sensors are very expensive. 
European reference EP 599 511 A1 discloses a further device for 
automatically actuating a transmission. This device comprises a shifting 
finger which can be deflected via assigned drives into an X-direction and 
a Y-direction perpendicular thereto. The absolute position of the shifting 
finger in the respective direction of movement or coordinates is detected 
in each case by assigned potentiometers. The potentiometers are used to 
detect the transmission position. 
Furthermore, the current which is applied to the drives during driving is 
sensed. If the sensed values deviate from predetermined values to more 
than a predetermined extent, the deviation of desired and actual values is 
reduced or corrected by running through a control loop. 
In the case of this device, as well, potentiometers which have a short 
service life because of the sliding-action contact required are provided 
for detecting position. 
German reference DE 36 13 800 C2 discloses an emergency actuation device 
which has a mechanical switch to be actuated by the driver. The switch has 
a plurality of actuating positions, the engagement of a predetermined 
driving gear being permitted by actuating the switch in a predetermined 
way. It is disadvantageous that the driver must, on the one hand, know how 
the emergency switch is to be actuated in the event of failure of the 
actuating device. Thus, in the stressful situation of a malfunction, the 
driver must have at his fingertips the required actuating routine in which 
the switch is to be actuated for the emergency actuation. This is very 
inconvenient for the driver. Furthermore, only a very restricted driving 
operation is possible, since only a predetermined driving gear can be 
engaged by the emergency switch. 
German reference DE 44 33 825 C2 discloses a sensor for detecting a 
relative movement that operates in a contactless fashion. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an actuating device 
having reduced production costs and a reduced susceptibility to 
malfunction. 
It was also an object of the invention to provide an emergency actuation 
device which is convenient for tale driver should a malfunction occur. 
Pursuant to these objects, and others which will become apparent hereafter, 
one aspect of the present invention resides in an actuating device having 
an output element, first drive means for driving the output element in a 
first direction, second drive means for driving the output element in a 
second direction, control means for controlling the first and second drive 
means, and first sensor means assigned to each of the drive means for 
detecting movement of the output element and outputting corresponding 
signals to the control means, which signals specify a respective magnitude 
of movement. The control means is operative to use the signals with 
reference to an arbitrary prescribable reference point to determine an 
actual position of the output element and relate the actual position to a 
desired position of the output element which is to be approached, whereby 
perception that the desired position has not been reached after 
termination of one of an actuating movement and an absence of signals 
which indicate the actuating movement causes the control means to activate 
an emergency function. The provision of an arbitrary reference point 
permits the use of sensors which pick up relative movements to detect the 
actual position of the output element with reference to the reference 
point. Sensors which operate without contact to detect a relative movement 
have been disclosed, for example, in German reference DE 44 33 825 C2. 
Such sensors are available cost effectively as standard components. In 
particular, sensors which operate without contact have the advantage, by 
contrast with potentiometer elements, of operating without wear and thus 
reliably. The signals of the sensors, which display a relative movement of 
the output element, are fed to a control device. For control purposes, the 
control device determines the ACTUAL position of the output element from 
the signals, which represent the relative movement, with reference to the 
reference point. In order to control the output element, the ACTUAL 
position is related to the DESIRED position. If the actuating movement has 
been terminated, and it has been detected that the DESIRED position has 
not been reached or that signals indicating an actuating movement are 
absent, for example due lo the failure of a sensor, the control device is 
caused to activate an emergency function. Failure to reach a DESIRED 
position which is to be approached can be detected, for example in the 
case of a prescribed driving gear to be engaged, by synchronization work 
performed by the driven drive. 
After the synchronization work has been performed, positioning the shifting 
shaft at the position corresponding to the complete, engaged driving gear 
requires low power. The synchronization point can be detected by the 
actuating speed or the power consumption of the drive driving the output 
element in the gear-selecting direction. It can also be provided to 
correct the ACTUAL position on the basis of a determined deviation of the 
detected synchronization point from the expected synchronization point, 
taking into account the magnitude of deviation. It is advantageous if the 
output element at least briefly occupies the reference point in an 
adjusting routine which is carried out in predetermined operating states. 
The DESIRED position is approached starting from the reference point. The 
output element is readjusted by the inclusion of the reference point, with 
the result that inaccuracies within the scope of the tolerance band, which 
add together in the course of the actuating operation, do not exceed a 
prescribed maximum. 
The adjusting routine is preferably run through upon starting the vehicle, 
with the result that a slight maladjustment already present is immediately 
corrected when starting the vehicle or when starting to drive. 
Furthermore, it is advantageous to activate the adjusting routine upon 
sensing of an actuation of the ignition lock and a further actuating 
signal such as, for example, a signal indicating actuation of the vehicle 
brake. The requirement for brake actuation upon starting the vehicle is 
already customary in conventional automatic transmission vehicles. 
In a further embodiment of the invention, a restricted adjusting routine 
can be activated by opening the driver's door. In the case of this 
restricted adjusting routine, the current gear position of the 
transmission is not changed. By approaching an end stop, it is possible to 
carry out a comparison with a reference value already stored in the 
memory, and the shifting shaft can be positioned at the desired position 
corresponding to the driving gear selected. 
In another embodiment the adjusting routine is run through when it is 
detected that a stop has been reached in the gear-selecting direction 
during normal driving operation. The DESIRED positions assigned to the 
driving gears are arranged with an offset upstream of the respective stop 
in the gear-selecting direction for the purpose of relieving the 
transmission in each case. Reaching a stop is evaluated as maladjustment 
which exceeds a predetermined maximum extent. It is thereby also ensured 
during the driving operation that maladjustment does not exceed a 
predetermined maximum. This maximum possible maladjustment must be 
dimensioned so as always to ensure fault-free actuation of the 
transmission to be actuated by means of the actuating device. 
In still an additional embodiment of the adjusting routine, starting from a 
change position, the output element occupies the reference point with 
reference to the second direction of movement. In this case, the change 
position is the position in which the output element has two degrees of 
freedom. In the case of an H shift mechanism, the change position is the 
idling position. Should the reference point with reference to the first 
direction of movement not yet be occupied, the output element occupies 
said point by renewed deflection in the first direction of movement. 
It has prosed to be advantageous that when at least one stop is reached, 
the reference point is occupied with reference to one direction of 
movement. The reference point is occupied in the slot-selecting direction 
when a stop is reached in a prescribed direction with reference to the 
direction of movement. It is particularly easy to approach such a stop 
position by driving the drive assigned to the direction of movement over a 
maximum required time interval in order to occupy the stop position. If, 
in the gear-selecting direction, the middle position or idling position is 
the predetermined position of the reference point with reference to the 
direction of movement, the reference point can be occupied by a single 
deflection in each direction of movement. A further sensor can be provided 
for detecting the change position, with the result that the change 
position occupied is detected by the control device. If the sensor is not 
provided, the output element can be occupied by prescribing a driving 
interval starting from a stop position in the gear-selecting direction. 
In a further embodiment of the invention, a control device comprising a 
time-measuring means is provided. In a prescribed first interval, the 
output element is prevented from further deflection in the prevailing 
direction of movement by reaching a stop. The first interval is 
dimensioned so as to always ensure that the stop is reached in the driven 
direction of movement. When the stop is reached, the position of the 
output element is exactly fixed in the direction of movement. If the 
direction of movement was the gear-selecting direction, starting from this 
position, the output element is driven in the opposite direction to the 
first direction of movement in order to occupy the change position. 
It is also advantageous to provide at least one drive with a power 
consumption detector. The power consumption of the respective drive can be 
used to detect that the output element has struck the stop from a rise in 
the power consumed by the drive. 
The control device is assigned a nonvolatile memory in which signals are 
stored which represent actuating paths. These signals can be picked up by 
means of the sensors assigned to the drives. Thus, the actuating paths 
corresponding to the various driving gears can be stored in the memory via 
the determined signals. If a driving gear is prescribed as a DESIRED 
position, the drives are driven by the control device in an appropriate 
way using the stored signals. The signals are to be input individually for 
each drive train configuration, in particular in order to adapt to the 
respective transmission. This compensates for deviations in the actuating 
paths assigned to the respective driving gears, which result from 
manufacturing tolerances. It is preferable to input the signals after 
mounting the drive train by engaging the individual driving gears in a 
predetermined sequence. This individual inputting compensates for 
production fluctuations. If a drive train configuration is changed, for 
example by replacing the transmission, it is necessary to modify the 
signals stored in the nonvolatile memory in order to ensure the optimum 
prescription of the DESIRED position corresponding to the desired gear. 
It is advantageous for the sensors to detect the actuating movement of the 
drives directly. The sensors detect the relative movement of the output 
part of the respective drive. In order to be able to use drives which are 
as small as possible, the drives are connected to the output element via a 
reduction gear. The magnitude of the movement of the output part of the 
drive is thus a multiple of the movement of the output element. 
Consequently, the magnitude of the resulting movement of the output 
element can be determined very accurately by detecting the movement of the 
output part of the drive. The sensors can be integrated directly in the 
drives in the case of this arrangement. The incremental encoders disclosed 
in German reference German reference DE 44 33 825 C2 have proved to be 
particularly suitable sensors. If the drive is provided with a friction 
clutch, the sensor is to be provided on the output side of the friction 
clutch in order to detect the movement initiated. 
It can also be provided for the corresponding drive to have a friction 
clutch, thus preventing overloading of the drive in the case of a stop 
being struck. If the stop is reached, a relative movement occurs between 
the drive-side input part and output-side output part of the friction 
clutch. Such a drive provided with a friction clutch has been disclosed, 
for example, in German reference DE 43 36 445 A1. 
In the case of an activated emergency function, the output element occupies 
the DESIRED position, starting from an emergency reference point. The 
output element is driven over a first emergency control time interval by 
the first drive in order to occupy the DESIRED position. The first 
emergency control time interval is dimensioned so as to ensure that the 
output element bears against the stop located in the drive direction. The 
position of the output element with reference to the first direction of 
movement is thereby known. This information is used to position the output 
element at the change position. In order to occupy the change position, 
the output element is advantageously driven by the first drive in the 
opposite direction over a definitively prescribed time interval. The time 
required to move the output element from the stop position into the change 
position is preferably stored in the control device. It can also be 
provided to position the output element at the change position by 
prescribing the power of the driven drive, for example by prescribing a 
predetermined drive power profile. 
In an additional embodiment, the output element is driven alternately by 
both drives shortly before potentially reaching the change position. If 
the output element can be deflected in the second direction of movement, 
the change position has been reached or already driven through. This drive 
ensures that, even in the case of drive fluctuations, for example due to 
the occurrence of difficulty of movement with the resulting, necessarily 
higher power or longer time, the change position will certainly be reached 
with the possibility of a change in the direction of movement, and that 
the output element occupies this at least briefly. It is not possible by 
means of a pure prescription of time or the prescription of a drive power 
profile to approach a prescribed position in a pinpointed fashion as 
exactly as when the magnitude of the actuating movement is detected and 
monitored by sensors. This relatively large fault tolerance can be 
compensated for when driving the two drives by alternately driving them in 
the region of the change position. It is also possible here to detect the 
change position when detecting the power consumed by the drives. If the 
output element cannot be deflected in the drive direction, there is a rise 
in the power consumed by the respective drive. If a deflection in the 
respectively driven direction of movement can be deduced from the power 
consumption of the two drives in two successive drive time intervals on 
the basis of a low power consumption, the change position is occupied or 
has already been driven through. Whether the change position has already 
been driven through or is only occupied depends on the magnitude of the 
drive time intervals. 
If the change position is occupied, the output element is brought to bear 
against the stop located in the drive direction by driving the second 
drive over a second emergency time interval. When this stop is reached, 
the position of the output element with reference to the second direction 
of movement is also known, with the result that the instantaneous position 
of the output element is known with reference to both directions of 
movement. Starting from this defined position, the output element is 
positioned at the emergency reference point if the stop position occupied, 
which is predestined to be an emergency reference point, is not the 
predetermined emergency reference point. 
If only one of the sensors assigned to the drives has failed, the signals 
of the sensors which are still serviceable can be used by the control 
device for pinpointed control of the drives. Furthermore, it has proved to 
be advantageous to assign the emergency function a nonvolatile memory in 
which drive time intervals or drive power profiles which are assigned to 
the various driving gears and intended for engaging the desired driving 
gear by means of the drives are stored. Consequently, further 
serviceability of the actuating device is ensured even in the case of 
failure of one or more sensors, it no longer being possible to approach 
the prescribed DESIRED position so exactly. It is therefore necessary to 
accept losses in convenience such as, for example, relatively frequently 
running through the adjusting routine and the lengthening of the time 
required to change a driving gear. It is therefore advantageous to display 
the activation of the emergency function to the driver so that he seeks 
out a workshop to remedy the effect as soon as possible. 
The various features of novelty which characterize the invention are 
pointed out with particularity in the claims annexed to and forming a part 
of the disclosure. For a better understanding of the invention, its 
operating advantages, and specific objects attained by its use, reference 
should be had to the drawing and descriptive matter in which there are 
illustrated and described preferred embodiments of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The principle of the inventive actuating device 1 is firstly described with 
the aid of FIG. 1. The actuating device 1 for actuating a manual 
transmission 6 by means of an auxiliary force comprises a first drive 3 
and a second drive 5. Two electric motors 21, 23 are provided as the 
drives 3, 5 in this embodiment. The first electric motor 21 has an output 
part which is in the form of a segmented wheel and has teeth 71 which 
engage with axially extending teeth, termed axial teeth 63 below, of a 
shifting shaft 12. On a further subsection, the shifting shaft 12 has 
radially extending (radial teeth) 61 which engage with teeth 73 of an 
output part, in the form of a segmented wheel, of the second electric 
motor 23. The electric motors 21, 23 are provided in each case with a 
sensor 13, 15, whose signals are relayed to a control device 2. The 
electric motors 21, 23 can be driven by the control device 2. The control 
device 2 comprises, for its part, an emergency control function 55 and a 
nonvolatile memory 45 in which signals corresponding to the various 
driving gears are stored. 
The mode of operation of the actuating device 1 will be considered in 
detail below. 
It can be provided that an adjusting routine is firstly run through each 
time the vehicle is started. In this case, the control device 2 can detect 
the driver's wish to start the vehicle, for example in the case of a 
signal present which indicates actuation of an ignition lock in 
conjunction with a signal which characterizes a further actuation, for 
example a signal derived from the brake lights or a signal characterizing 
brake actuation. The actuated brake simultaneously prevents the vehicle 
from rolling away when the adjusting routine is being run through. 
Once the adjusting routine has been run through or virtually run through, 
the starter is released by the control device. 
With at least one restricted version, in which there is no need to 
disengage an engaged driving gear, it can also be provided to activate an 
adjusting routine by opening the driver's door with the handbrake applied. 
In the restricted version of the adjusting routine, it is not mandatory to 
secure against rolling away by means of an actuated brake. 
The driving of the drives by the control device 2 is examined in more 
detail below. 
When the vehicle is started, the shifting shaft 12 is positioned by 
appropriately driving the drives 3, 5 by means of the control device 2 to 
a reference point 49 (see FIG. 3) stored in the control device 2. If the 
driving gear was engaged when starting the vehicle, the first drive 3 is 
firstly driven by the control device 2 to disengage the driving gear. 
While the first drive 3 is being driven, the relative movement of the 
output part 11 is picked up by the sensor 15 assigned to the first drive 
3, and relayed to the control device 2. With the aid of this signal, the 
control device 2 determines the instantaneous position, and positions the 
output part 11 exactly at the change position 53, which is here the idling 
position 54. When the idling position 54 is occupied, the output element 
11, here the shifting shaft 12, is positioned at the slot position 
corresponding to the reference point 49 by driving the second drive 5. It 
is not necessary to detect this actuating movement if the first or last 
slot is the selected reference point 49 in the slot-selecting direction 
31. If, for example, the first slot is selected as the reference point 49 
in the slot-selecting direction, the shifting shaft 12 is brought into the 
stop position 27 by the second drive 5. The second drive 5 is driven by 
the control device 2 so as to ensure that the stop position 27 is reached. 
For example, it can be ensured that the stop position 27 is reached by 
driving the drive 5 by prescribing a predetermined time interval of a 
prescribed drive profile or via the drive power detected by a power 
consumption detector 59. 
The driving gear determined by the control device 2 is prescribed as a 
DESIRED position. The control device 2 now returns to the signals stored 
in the memory 45 and assigned to the driving gear. The drives 3, 5 are 
driven in the predetermined fashion in accordance with said signals. The 
actuating movement initiated by the respective drive 3, 5 is sensed by the 
sensor 13, 15 and fed to the control device 2, with the result that the 
drives 3, 5 are driven as a function of the sensor signals fed to the 
control device 2. The shifting shaft 12 is thus adjusted by being 
controlled away to the DESIRED position. If the path prescribed for 
occupation has been covered, the actuating movement is thereby terminated. 
It can be provided in addition to include the signals representing the 
force required, if this information is available to the control device 2. 
If the need to change gear is detected by the control device 2, the 
position assigned to the driving gear is the new DESIRED position. The 
path to be covered in order to occupy the DESIRED position 47 assigned to 
the driving gear is predetermined by means of the signals stored in the 
memory 45. The path can be provided for occupying the direct drive without 
briefly occupying the reference point 49. The new DESIRED position is then 
approached by forming the difference between the paths to be covered. The 
drives 3, 5 are driven in accordance with the paths to be covered. If a 
mechanical striking of a stop 25, 27, which can be arranged in the 
transmission or in the housing of the actuating device 1, is detected 
during the drive, the striking is evaluated as maladjustment. Striking the 
stop 25, 27 can be detected while the drive is being driven, for example 
by a missing signal of the sensor 13, 15 assigned to the driven drive 3, 
5. Starting from this position, the drives 3, 5 are driven to occupy the 
reference point 49. If a stop 25 assigned to a driving gear is occupied, 
the idling position 54 is approached first. The direction of the first 
drive 3 driving the shifting shaft 12 is reversed for this purpose. The 
shifting shaft 12 is driven in the opposite direction. If the expected 
signal of the sensor 13 assigned to the first drive 3 continues to be 
missing, the emergency function 55 of the control device 2 is activated. 
If the first drive 3 is defective, the desired driving gear can no longer 
be engaged automatically. As a result, the vehicle remains stationary. If 
the sensor 13 indicating the actuating movement is defective, the DESIRED 
position is occupied, under the control of the emergency function 55. The 
mode of operation of the emergency function 55 is to be examined in detail 
later. 
A maladjustment is present if, with the reversal of the driven direction of 
the first drive 3 driving the shifting shaft 12, the control device 2 
again receives from the sensor 13 a signal indicating an actuating 
movement. If a stop has been occupied during selection of a gear, the 
first drive 3 is driven to disengage the gear. When the idling position 54 
is occupied, the reference point 49 is approached in the slot-selecting 
direction 31. As previously described, the DESIRED position is approached 
starting from the reference point 49. 
A maladjustment in the gear-selecting direction 33 and the slot-selecting 
direction 31 is corrected by running through the adjusting routine. If, 
when the DESIRED position is being approached in the slot-selecting 
direction 31, the stop is struck in the case of a reference point 49 
deviating from the stop 27, a maladjustment is detected. If the actuating 
path between the two stops 27 present in the slot-selecting direction 31 
is stored in the control device, it is possible to carry out a correction 
without approaching the reference point 49 from knowledge of the 
instantaneously occupied stop position 27. 
If the stop 25 has been occupied in the gear-selecting direction 33, it is 
possible to carry out a correction by approaching the position 26, which 
is arranged with a prescribed offset 24 upstream of the stop 25 and 
assigned to the gear. It is necessary for this purpose for the actuating 
path corresponding to the offset 24 to be stored in the control device 2. 
These corrections are relative corrections by means of which it is 
possible to compensate for an error which has occurred by summing up the 
inaccuracies caused by the fault tolerance. However, if the instantaneous 
actuating position of the shifting shaft 12 is entirely unknown because of 
a brief malfunction, it is necessary to run through the adjusting routine 
for the purpose of readjustment. 
The emergency function of the control device 2 is described in more detail 
below. With the emergency function 55 activated, it is possible to occupy 
a prescribed DESIRED position without the signals indicating the actuating 
movement. The stop positions 25, 27 are known from the signals stored in a 
memory 57 assigned to the emergency function 55, or in the memory 45 in 
the control device 2. If the stop 25 is occupied in the gear-selecting 
direction 33, the shifting shaft 12 is positioned at the idling position 
54, given the prescription of a drive time or a drive profile. Starting 
from the idling position 54, the emergency reference point 51 is occupied 
in the slot-selecting direction 31. The prescribed DESIRED position is 
approached by means of the signals stored in the nonvolatile memory 57 of 
the emergency function 55. Each DESIRED position, such as a driving gear 
or the idling position, is assigned a drive profile or drive time profile 
in the memory 57 by means of signals. This approaching of the prescribed 
DESIRED position is not as exact as the approach during normal operation. 
It can be provided that the emergency reference point is occupied at least 
briefly for each gear change. The active emergency function 55 is 
indicated to the driver. 
A further embodiment is described with the aid of FIG. 2. In the case of 
this actuating device 2, the drives 3, 5 are provided with friction 
clutches 75, thus preventing overloading of the respective drive 3, 5 in 
the case of continuing driving when the stop 25, 27 has already been 
occupied. The sensors 13, 15, here incremental encoders 17, 19, for 
sensing the actuating movement are respectively arranged on the output 
side of the friction clutch 75. The friction clutch 75 is designed so that 
it provides a firm connection between the output part of the drive and the 
shifting shaft 12 during normal actuating operation. If the shifting shaft 
12 strikes the stop by continuing to be driven, the friction clutch 75 
slides through. The respective sensor 13, 15 detects no or a greatly 
reduced actuating movement. The control device 2 evaluates this as 
maladjustment. As already described with the aid of FIG. 1, the drives 3, 
5 are driven for readjustment. 
The control device 2 also has a time-measuring means 35 in this embodiment. 
The idling position 54 can be approached starting from a selected gear by 
prescribing a drive time interval of the drive 3. Signals, by means of 
which a prescribed DESIRED position can be approached by prescribing drive 
times of the drives 3, 5, can be stored in the memory 45 of the control 
device 2 or the emergency function 55. Differing from the embodiment 
represented in FIG. 1, the manual prescription of a DESIRED position can 
be prescribed manually by the driver by positioning a gear shift lever 39 
provided with a sensor 29, 41, as disclosed in German reference DE 38 36 
145 A1, for example. 
FIG. 3 shows a shifting gate 43 of an H shift mechanism. The shifting gate 
43 is assigned to the gear shift lever 39 and is virtually integrated into 
the control device 2 in the case of the actuating device 2 without a shift 
lever 39. The DESIRED positions 47 corresponding to the shift positions 40 
of the driving gears 1-5 and R have been fixed with an offset 24 ahead of 
the stop 25 assigned to said gear. 
In the embodiment represented in FIG. 4, a further sensor 65 is provided, 
which indicates the idling position. In this embodiment, the incremental 
encoders 17, 19 sensing the actuating movement are connected to the 
shifting shaft 12. The mode of operation of the actuating device 2 does 
not differ from the mode of operation of the actuating device 2 described 
with the aid of FIG. 1, except that the sensor 65 senses when the idling 
position 54 is reached and relays this to the control device 2. The half 
side on which the shifting shaft is located is additionally known from the 
signal, led from the sensor 65 to the control device 2, by means of the 
sensor 65 represented in the illustrated embodiment. Consequently, the 
required driving direction of the drive 3 for directly occupying the 
idling position is known. The sensor 65 represented is only an exemplary 
embodiment of a multiplicity of sensors which can be used to detect a 
prominent position. 
In the actuating device 1 represented in FIGS. 6 and 7, the drives 3, 5 are 
connected via a transmitting element 37 firmly connected to the shifting 
shaft 12. The transmitting element 37 comprises a segmented wheel part 38 
with the first teeth 71 which engage with the output part 67 of the first 
drive 3. When the first drive 3 is driven, the segmented toothed wheel 
part 38, and thus the shifting shaft 12 are driven in a rotary fashion. 
The transmitting element 37 has second teeth 73, which are arranged at 
right angles to the first teeth 71 and parallel to and coaxial with the 
shifting shaft 12, and which engage with the output part 69 of the drive 
5. The initiated torque of the respective drive 3, 5 is transformed by the 
radial spacing between the teeth 71, 73 relative to the shifting shaft 12. 
The teeth 71, 73 are constructed so that the shifting shaft 12 can be 
driven by the drives 3, 5 in a decoupled fashion in the various directions 
of movement 7, 9. The second teeth 73 extend over a region in the 
circumferential direction in a fashion coaxial to the shifting shaft 12, 
with the result that when the transmitting element 37 is deflected in a 
rotary fashion by the first drive 3 it is ensured that the second teeth 73 
engage with the output part 69. The transmitting element 37 is provided 
with the sensors 13, 15, which detect the respective actuating movement of 
the shifting shaft 12. 
The remaining design, and the mode of operation of said actuating device 1 
is no different from the actuating device 1 described with the aid of FIG. 
1. 
The invention is not limited by the embodiments described above which are 
presented as examples only but can be modified in various ways within the 
scope of protection defined by the appended patent claims.