GB2350164A - Gearbox actuating device having a single actuator that produces angular and axial motion - Google Patents

Abstract

A gearbox actuating device comprises an electric motor 2 that drives a spindle 54 with helical teeth 53 which engage with an output element 55 connected to a selector shaft 10. A switching mechanism 49 has a locking element 50 that, via first and second claws 39, 41 engaging in first and second recesses 43, 45, applies either angular or axial motion to the shaft 10. When the first claw 39 is in one of the first recesses 43 the shaft 10 is locked axially but allowed to move angularly, so as to select a ratio in a lane, since the second claw 41 is on axis of rotation 47. With the first claw 39 disengaged the second claw moves, in the second recess 45, away from the axis of rotation 47 so that the shaft 10 is locked angularly but allowed to move linearly, so as to select the lane. This construction is compact and overload protection is provided to reduce wear in operation. In other embodiments two electric motors are used, to provide axial and angular motion, and various forms of damping devices are also disclosed.

Description

2350164 MOTOR VEHICLE GEARBOX ACTUATING DEVICE The invention relates to an

actuating device for an output member movable with two kinds of motion for actuating a motor vehicle gearbox, the device including at least one actuating drive for the output member.

DE-A-43 11 855 shows an actuating device for actuating a selector shaft of a change-speed gearbox of a motor vehicle. This actuating device has a first drive for moving the shaft in one kind of motion and a second drive for the other kind of motion. The two drives are arranged perpendicular. As illustrated in Figure 19 the rotation of the selector shaft is achieved by the first drive. The first drive moves a toothed rack linearly, this rack meshing with a pinion rigidly connected to the selector shaft. The displacement of the selector shaft is effected by the second drive. The second drive is operatively connected to the selector shaft so that the linear movement is the drive is transmitted directly to the selector shaft to displace it. Because of this displacement movement the pinion, which is rigidly connected to the selector shaft for rotational movement must have a large enough axial dimension so that the rack always meshes with the pinion.

A disadvantage of this device is that the permanently engaged teeth of pinion and rack slide along one another on displacement of the selector shaft. As a result these teeth are heavily loaded. This results in wear on the teeth, thus increasing the clearance between the teeth. The increased clearance reduces the reliability of the selector shaft in selecting the gear, and so is disadvantageous, as reliable operation over a large number of gear-changing operations must be achieved. For this reason the device is not really suited to the operation of the selector shaft of a change-speed gearbox.

2 It is an aim of the invention to provide an actuating device for an output member for actuating a motor vehicle gearbox, which has compact construction and has low wear in operation.

According to the present invention, in an actuating device for an output member movable with two kinds of motion for actuating a motor vehicle gearbox, the device including at least one actuating drive for the output member, a single actuating drive operates the output member for both kinds of motion, and a switching mechanism operates to switch the output member between operation in the two kinds of motion and to predetermine the position of the output member for one kind of motion.

Using a single drive with a switching mechanism able to predetermine the position of the output member for one kind of motion means that the second actuating drive can be eliminated, saving cost and space. Although a switching drive is needed for the switching mechanism, this can be of low power and therefore compact construction.

Preferably the switching mechanism predetermines the position of the output member for selecting the gearbox selector lane, and the other kind of motion is used to select the ratio in the lane.

It has been found advantageous for the switching mechanism to include a locking element. Each of the two kinds of motion can be blocked separately by this locking element so that the output member is driven by the actuating drive only in the non-blocked kind of motion. Preferably the locking element has a first claw which locks the output member against axial movement by engaging without axial clearance in a first recess in the output member, and a second claw which locks the output member against 3 angular movement by engaging without circumferential clearance in a second recess in the output member.

Preferably a number of first recesses are associated with the first claw, each recess defining a lane of the gearbox which is operated by the output member.

A rapid engagement of a gear ratio is achieved by a large operating torque. It has been found to be advantageous for this if the second claw always remains in the second recess, and to release its locking is movable into a position in which it has circumferential clearance in the second recess to allow angular movement of the output member.

An alternative, and particularly favourable embodiment is where the second recess comprises a slot, and locking is released by moving the second claw to a position on the axis of rotation of the output member, to allow angular movement. In this embodiment as soon as the second claw is moved to a position other than on the axis of rotation of the output member angular movement of the output member is blocked. This provides switching between the kinds of motion in a particularly easy way, without overlapping between them. The output member is always only driven exclusively in the direction of one kind of motion, that is, angular or linear.

The actuating drive is preferably connected to the output member through helical teeth. The output drive element of the teeth is connected rigidly to the output member. The helical teeth can transmit both angular and linear movement to the output member of the actuating device in a simple manner. The gearing known from DE-A-38 36 368 has been found to be particularly suitable.

4 It is advantageous for the actuating drive to have an overload protection means, which is activated on faulty control of the drive in order to prevent transmission of the driving movement of the gearing element on reaching a stop associated with this gearing element. Where the drive is an electric motor this protects it from overload which could lead to overheating the motor. Further, the mechanical loading of the components engaging the stop or forming the stop is reduced. Excessive mechanical loading which could lead to fracture of the components is prevented.

Advantageously the overload protection means comprises a slipping clutch which is activated on continuing motion of the drive in contact with a stop in the prevailing direction of movement. Such a clutch can be incorporated in an electric motor. If the movement produced by the electric motor is detected by means of sensors, the sensors preferably follow the slipping clutch so that the actual gear movement and position is detected.

Preferably the overload protection means includes resilient elements, which when predetermined positions of the gearing element are reached deform elastically in opposition to the force from the drive, to damp the movement of the gearing element. In this way a maximum deflection in the currently prevailing direction of movement is achieved only in the form of a damped movement.

Preferably electric motors are used as the actuating drives. These are obtainable as economical standard components and are particularly suitable for the purpose. These electric motors are drives which operate rotationally. The power needed to operate them can be obtained from a generator driven by the internal combustion engine of the vehicle. In comparison to this, hydraulically driven actuating devices have the drawback that an hydraulic system must be provided for operating the actuating device. The hydraulic system comprises a pump, a pressure accumulator and several valves, so the cost of providing the necessary hydraulic power is substantial. Further, because of the leakage which is always present in an hydraulic system the energy consumption is 5 substantially greater than for an electrical system.

A further advantage of electric motors is that the supply connections are easy to install and take up little space.

A particularly advantageous further feature is to connect the actuating drive to a flange by which it is mounted on the gearbox, the flange also providing a mounting for additional elements allowing further functions. The flange has at least one opening. One opening may be provided for the passage of the gear lever in a manual gear-change vehicle.

In this way the actuating device can be installed without requiring modification of the gearbox housing. Another opening can be made for the introduction and removal of gearbox oil, closed by a closure element. The flange may also have openings for sensors. It is advantageous to sense the temperature of the gearbox and in the neighbourhood of the gearbox in order to take account of the increase in the force needed to engage a gear ratio with decreasing temperature in the control of an automated gearchanging sequence. Also a sensor for detecting the gearbox input shaft speed can be incorporated, this being required in many vehicles for control purposes (e.g. ABS). Accordingly the additional elements are arranged centrally on the flange so that the necessary input and output connections can be placed on this flange in a bundle, which is advantageous in manufacturing.

Preferably the actuating drive is provided with a device allowing manual actuation of the output element of the drive. Then, where a vehicle 6 has been left idle with a gear engaged, but the electronics are out of action the gear can be disengaged by means of this device through manual operation. The gearbox can be put into neutral and the vehicle can be towed in the usual manner. However, before the gear ratio is manually disengaged it must be checked that the hand brake is engaged in order to prevent the vehicle rolling away on disengagement of the gear.

Also the drive can be provided with a device for a manual operation, by which the drives can be shifted in the direction of movement driven in normal operation. In this way it is possible to engage a gear ratio manually, in particular to engage a starting gear.

The actuating drive has a device by which a motor spindle of the drive rigidly connected to the drive output element is operable manually.

The end of the motor spindle may then have at its end a profile engaged by a complementary profile of an actuating element for manual operation. Preferably the actuating element is a tool which is carried in the vehicle. However, this device can also be provided at another point. In some circumstances it is of advantage to select a position which is arranged to be particularly easily accessible, as in some circumstances, a gearbox may be needed for a power take-off.

The output element of the drive can be put in the desired position, preferably the idling position by manual operation. The desired position can be identified by the actuating force which has to be exerted. For example, the engagement and disengagement of a gear ratio requires a greater force than moving the output element in the idling range so that the idling or neutral position can be recognised by the easy manual operation.

7 Various embodiments of the invention are illustrated by way of example in the accompanying drawings, in which:

Figure 1 shows an actuating device which does not fall within the scope of the invention, the device being in longitudinal section with a crank drive; Figure 2 is a side view of the actuating device of Figure I with a section on the line II-II.

Figure 3 is like Figure I but with a rack; Figure 4 is like Figure I but with a cam drive; Figure 5 is a side view of the actuating device of Figure 4 with a section on the line V-V; Figure 6 is like Figure 1 but with a solenoid as the drive; Figure 7 shows the solenoid arrangement for achieving a pivotal movement; Figure 8 is a side view of Figure 7 looking from the right; Figure 9 is like a Figure I but with a compensating spring on the drive; Figure 10 is a side view of the actuating device illustrated in Figure 9 with a section on the line X-X; 30 8 Figure 11 shows an actuating device in accordance with the invention, with a switching mechanism and only one actuating drive; Figurella is a view onthe section line A-A in Figure 11; Figure 12 shows a locking element in side view on the section line XII-MI in Figure 11; Figure 13 shows an angular locking element; Figure 14 is like Figure 13 but showing a constructionally different embodiment; Figure 15 shows an overload protection means with resilient elements; Figure 16 shows an overload protection means with pre-loaded spring elements; Figure 17 shows a segmental gearwheel with stop damping as overload protection means; Figure 18 shows overload protection means incorporated in the segmental gearwheel, the view being on the line III-III; 25 Figure 19 is a section on the line IV-IV of Figure 18; and Figure 20 shows a perspective view of an actuating device with a flange and additional elements. 30 9 The actuating device 1 of Figures 1 and 2 is for an output member 9 movable with two kinds of motion for actuating a motor vehicle gearbox (not shown). The output member 9 is movable axially and angularly by respective actuating drives 3, 5, so that the device does not fall within the scope of the invention. The first drive 3 is connected pivotally through a crank gearing arrangement 14 to a slide element 7. The slide element 7 is mounted slidably in a sleeve 23 and has at its end a radial projection 27 which passes through a slot 25 formed as an axial gap 26 in the sleeve 23 and engages in a radial gap 28 in the tubular output member 9. The projection 27 has no axial clearance in the gap 28 but does have circumferential clearance. The slide element 7 moves linearly and axially on operation of the drive 3, and takes the output member with it.

The output member 9 also has an axial opening 35 in which an axial projection 33 on a segmental gearwheel 31 mounted on the sleeve 23 engages. The gearwheel 31 meshes through its teeth with a toothed shaft of the second drive 5 acting through reduction gearing 6. The drive 5 acts to move the gearwheel 3 1, and, via the projection 3 3, the output member 9, angularly. The output member can however move axially relative to the gearwheel 3 1.

The actuating device 1 is used for automated operation of a selector shaft 10 of the change-speed gearbox. Here the selector shaft 10 is the output member 9 of the actuating device. The first drive 3 operates with an oscillating movement and drives the crank gearing 14. The crank gearing 14 is connected to the slide element 7 which performs a linear axial movement. The linear movement of the slide element 7 is transmitted to the output member 9 through the projection 27, the slide element sliding in the sleeve 23.which supports it. The radial projection 27 on the slide element 7 is supported circumferentially by the axial slot 25 in the sleeve 23. The desired selector lane of the gearbox is set by means of this linear movement transmitted to the output member 9. The chosen ratio in the lane is put into effect by angular movement of the output member 9 and selector rod 10. The required angular movement is provided by the second drive 5, acting on the segmental gearwheel 3 1. Angular movement of the segmental gearwheel 31 is transmitted to the output member 9 through the projection 33. The output member 9 and the segmental gearwheel 31 are relatively axially slidably so that a linear movement transmitted to the output member 9 has no influence on the position of the segmental gearwheel 31. The slide element 7 is connected rotationally to the output member 9 so that angular movement of the output member 9 from the second drive 5 has no influence on the slide element 7. A larger force is needed for engagement of the desired ratio than for selecting the lane so that a more powerful drive is required for this. In order to minimise the drive 5, it is provided with reduction gearing 6.

The drives-3, 5 are rigidly connected to a flange 117 (Figure 20) connected to the gearbox housing which closes off the opening which was previously needed for the passage of the gear lever. The flange 117 and the housing 8 could also without difficulty be made in one piece.

The actuating device 1 of Figure 3 is similar to that of Figure 1, and corresponding reference numerals have been applied to corresponding parts. In Figure 3 a toothed rack 15 is driven by the first drive 3 to perform a linear movement which is transmitted to the slide element 7. As shown, the slide element 7 and the rack 15 are made in one piece. An output element 4 of the first drive, which operates in rotation, engages in the rack 15. Rotation of the output element 4 of the first drive 3 moves the rack 15 axially.

11 Figure 4 and 5 show another modification of the actuating device in which the crank gear 14 is replaced by a cam arrangement 17 associated with the first drive 3. The rotating output element 4 of the first drive 3 meshes with a gearwheel 16 which is rigidly connected or integral with a cam 18. The end of the slide element 7 engages the cam 18 and is held in contact with the cam 18 by means of return spring 19 located in the sleeve 23. However, it is also possible to produce the operative connection between cam 18 and slide element 7 through a groove and peg connection (not shown).

Figure 4a shows a modified cam 18 which has a number of substantially flat plateaus 24. One selector lane is associated with each of these plateaus.

Figure 6 shows an actuating device 1 having a solenoid 21 as the first drive 3. The adjacent end of the slide element 7 projects into the solenoid 21. A return spring 19 acts on the opposite end, which has the radial projection 27. When the solenoid 21 is energised by an electric current the slide element 7 is moved axially against the force of the spring 19 dependent upon the applied current or the applied voltage. The selection of the lane is performed by means of the solenoid 21.

Figures 7 and 8 show a modification of Figure 6, in which the lane selection is performed by an angular movement. In Figures 7 and 8 an output member 22 of the solenoid 21 acts on a motion-converting lever 30 which is rigidly connected to the selector shaft 10. A return spring 19 is provided on the opposite side from the solenoid 21 and ensures a positive connection between lever 30 and output member 22 of the solenoid 21.

Actuation of the solenoid 21 mover the output member 22 against the restoring force exerted on the lever 30 by the return spring 19.

12 The actuating device 1 of Figures 9 and 10 is similar to that of Figures 1 and 2 but has in addition a compensating spring 36. This is associated with the segmental gearwheel 3 1. The compensating spring 36 is rigidly connected to the segmental gearwheel 31, which is rotated by the second drive 5, and it also abuts against the housing 8 of the actuating device 1. In the central position of the segmental gearwheel 31 the compensating spring 36 is under its maximum stress. On movement of the segmental wheel 31 by the second drive 5 the spring force assists the torque delivered by the drive 5. This assists and accelerates the engaging process of the selected gear ratio. The segmental gearwheel 31 is returned to its central position by means of the second drive 5, and this stresses the compensating spring 36 once again. The force which is necessary is provided by the second drive 5. This direction of movement of the gearwheel is associated with the disengagement of an already-engaged ratio.

A lower force is required for disengaging an engaged ratio than for engaging a ratio as no synchronisation effort has to be exerted within the gearbox. For this reason the second drive 5 can have lower power, but still be able to engage a gear by virtue of the compensating spring 36.

Figures 11 to 14 show an actuating device 1 which in accordance with the invention has only one actuating drive 2. A selector shaft 10 as the output member 9 of the actuating device 1 is driven axially and angularly by this actuating drive 2 through helical teeth 53. The helical teeth 53 are provided on a spindle 54 driven by the actuating drive 2. This spindle 54 is mounted at its free end by means of a bearing 63 supported in the housing 8 and meshes with an output element 55 rigidly connected to the selector shaft 10. The output element 55 and selector shaft 10 may be made in one piece.

13 The selector shaft 10 has an associated switching mechanism 49 which includes a locking element 50. This locking element 50 is arranged on the end 67 of the selector shaft 10 remote from the gearbox. The locking element 50 comprises a switching drive 59 and a detent means 65 comprising a first claw 39 and a second claw 41. First recesses 43 are associated with the first claw 39 and a second recess 45 is associated with the second claw. The first recesses 43 are formed axially spaced apart relative to one another and each extends circumferentially round part of the outer surface of the selector shaft 10. The second recess 45 is arranged in the end 67 of the selector shaft 10, and comprises an axial slot intersecting the axis of rotation 47 of the selector shaft 10.

By operation of the switching drive 59 the detent means 65 can be brought into different operative positions by which either kind of motion - axial or angular - can be applied to the selector shaft 10. In a first operating position, which is illustrated in Figure 11, the first claw engages in one of the first recesses 43, so that the selector shaft 10 is locked against axial movement. Engagement of the first claw 39 in a first recess 43 means that the second claw 41 is located on the axis of rotation 47 of the selector shaft 10, so that the shaft 10 can move angularly about the axis 47 and the claw 41. Consequently angular movements of the actuating shaft 10 can be produced by means of the actuating drive 2 operating through the helical teeth 53. In a second operating position the first claw 39 is withdrawn from the first recesses 43. This moves the second claw 41 into a position other than on the axis 47 of the shaft 10. In this position the second claw engages the second recess 45 without any circumferential play, so that the shaft 10 is locked against angular movement. The actuating drive 2 then transmits a linear movement to the selector shaft 10 as the spindle 54 carrying the helical teeth 53 has a helical inclination in an axial direction.

14 Figure 12 is a section showing the switching drive 59 and the first claw 39 engaging in one of the first recesses 43. Angular movement of the selector shaft 10 which axially locked is permitted by the circumferential extent of the first recess 43.

Figures 13 and 14 show further examples of locking elements 50, which have a different way of blocking angular movement of the selector shaft 10. In Figure 13 the second recess 45 does not intersect the axis of rotation 47 of the selector shaft 10. Instead, the second recess 45 is formed on a portion of its radial extent with circumferential extensions to permit angular movement. In the operating position in which angular movement of the selector shaft 10 are permitted, the second claw 41 engages the extended part of the recess 45 in the position indicated in broken lines in Figure 13. The locking element illustrated as an alternative in Figure 14 shows a second claw 41 of trapezium shape. This claw 14 engages the second recess 45 which is likewise of trapezium shape. The clearance between second claw 41 and second recess 45 is set by the radial position of the claw 41. When second claw 41 and second recess 45 are engaged without any circumferential clearance, as indicated in broken lines in Figure 14, the selector rod is blocked against angular movement.

Figure 15 shows the portion of the actuating device 1, which transmits the movement from the first drive 3. The construction shown differs from the construction of Figure 1 by the provision of overload protection means 69. The basic operation described in relation to Figure 1 is otherwise the same.

The overload protection means 69 of Figure 15 has resilient elements 75. These resilient elements are formed by helical spring element 77, 79 mounted coaxially round the slide element 7. These spring elements 77, 79 are in their turn surrounded coaxially by the sleeve 23 which mounts the segmental gearwheel 3 1. The spring elements 77, 79 are arranged in the ends of the sleeve 23. The slide element 7 is provided with radial projections 85, 87 forming radial engaging faces for the spring elements 77, 79. The diameter of the slide element 7 is increased by these radial projections 85, 87, but only to a small extent, so that the diameter is still smaller than the inside diameter 101 of the sleeve 23. The sleeve 23 has at its end radially inwardly extending projections 89, 91 formed by rings which represent respective second engaging faces for the spring elements 77, 79.

If there is a faulty control of the drive 3, and the slide element 7 is moved beyond its normal axial extent then for example the projection 87 on the slide element 7 comes into contact with the spring element 79. The kinetic energy of the slide element 7 is at least partially converted into potential energy by deformation of the spring element 79 which is engaged and the slide element is braked. This prevents the impact of the radial projection 27 against a stop 88. For movement in the other axial direction the projection 85 and spring element 77 are operative.

The construction illustrated in Figure 16 is another example of a damping stop forming overload protection means 69. This embodiment includes an intermediate sleeve 93 in which the spring elements 77, 79 are arranged. The spring elements 77, 79 are stressed in the intermediate sleeve 93. In this case the slide element 7 is formed by a rack 15 and the intermediate sleeve 93, the damping stop being incorporated in this sliding element 7. On its end remote from the drive the intermediate sleeve 93 has radially inwardly extending projections 95 forming an abutment face for a first spring element 79. In assembly, the first spring element 79 is inserted in the sleeve 93. The rack 15, which has a projection 99 forming a radial 16 coaxially extending abutment faces for the spring elements 77, 79 is slid in.

The second spring element adjacent the drive 3 is slid onto the rack 15 and the intermediate sleeve 93 is closed at its end, for example by shrinking in a closure ring 97. The spring elements 77, 79 are trapped in the intermediate sleeve 93. The spring elements 77, 79 could be provided on closing with predetermined pre-load controlled by the axial depth of insertion of the closure ring 97. If soft springs are inserted they are provided with a pre load such that under normal operating conditions the springs represent a rigid connection between rack 15 and intermediate sleeve 93. If the radial projection hits a stop 88 the kinetic energy of the rack 15 is at least partially coverted into potential energy of the associated spring element and a relative movement takes place between rack 15 and intermediate sleeve 93.

Figure 17 is a segmental gearwheel 31 provided with a damping stop as overload protection means. The maximum excursion of the segmental gearwheel 31 is limited on each side by a stop 105. The segmental gearwheel 31 is in its turn provided at the level of the stops with recesses 103 for receiving spring elements 81, 83 which extend beyond radially extending boundary edges of the segmental gearwheel. In the event of faulty control of the drive 5 and if the segmental gearwheel 31 moves beyond the usual extent, the spring element, for example 8 1, on the corresponding side comes into engagement with the stop 105 associated with this spring element. The kinetic energy of the segmental gearwheel 31 is converted into potential energy by deformation of the spring element 81 so that impact of the segmental gearwheel 31 is delayed.

Figures 18 and 19 show a segmental gearwheel 31 which includes overload protection means 69 having spring elements. The segmental gearwheel has a recess 109 for receiving an inner segmental wheel portion 107. Segmental wheel 31 and inner segmental wheel portion 107 17 are connected through two spring elements 81, 83, one on each side of the inner segmental wheel portion 107 tangentially between the latter an the segmental gearwheel 31. The inner segmental wheel portion 107 is rotatably mounted on the sleeve 23, easy rotation being ensured by means of a journal bearing 111, and has an axial projection 33 engaging in the longitudinal groove in the output member. The segmental gearwheel 31, surrounding coaxially a partial portion of the inner segmental wheel portion 107, is rotatably mounted onthe latter. The inserted spring elements 81, 83 have a spring constant such that on correct operation of the drive 5 a fixed connection is ensured between segmental gearwheel 31 and inner segmental wheel portion 107.

In operation, faulty control of the drive 5 means that the inner segmental wheel portion 107 can engage a stop arranged in the gearbox.

This prevents further rotation of the inner segmental wheel portion 107. The segmental gearwheel 31 continues to be driven by the drive 5. The kinetic energy of the segmental gearwheel 31 is converted into potential energy by deformation of at least one of the spring elements 81, 83, with relative movement taking place between inner segmental wheel portion 107, the one spring element being loaded in tension and the other in compression. Further possible examples of damping stop arrangements for a segmental gearwheel are known for example from DE-C-195 25 840. The overload protection means of Figures 15 to 19 can be adapted as appropriate to the embodiments of Figures 11 to 14.

Figure 20 shows a perspective view of an actuating device I with a flange 117 for mounting on a gearbox. This flange 117 has an opening 121 for the introduction and removal of gearbox oil. As a further additional element 119 there is formed an opening for a speed sensor 125 projecting into the gearbox for detecting the speed of the gearbox input shaft. A 18 temperature sensor 127 extends into the housing 8 of the actuating device 1, although it is also possible to arrange this temperature sensor 107 to project into the gearbox through an opening provided for it. This temperature value is fed to a control device, for controlling an automatic gear change. Then the drive can be operated from the control device taking account of the temperature in the gearbox, as the actuating force needed for engaging a gear is larger at lower temperatures. In this embodiment the drive 5 is provided with a slipping clutch 73. A slipping clutch 73 may be integrated into the drive housing or into the electric motor 57. Furthermore this actuating device is Provided with a number of sensors 129, 131 for detecting the actuating movement introduced by the drives.

1 The second drive 5 has at its free end a device 133 for manual operation of the output element 5b of the second drive 5. This device 133 is achieved by the provision of an end of the motor spindle 135 provided with a profiled shape. This end of the motor spindle 135 is closed off by a closure element 139 in the motor housing of the second drive 5.

In operation, if the vehicle is left standing with a gear engaged and with the clutch engaged, it cannot be towed by another vehicle. With the electronics out of action the driver is not able to change gear. Furthermore, if the vehicle is provided with ABS (anti-lock braking system) and the clutch is engaged the driver cannot change gear under no load. The manual operation of the device 1 can then be used. The driver is able, by opening the bonnet and removing the covering element, to operate the motor spindle 135 manually to move the gearbox into a neutral position. The neutral position, here an idling position, is recognised by the actuating force which has to be applied. However, it is also possible, if the gear which is engaged is known, to prescribe a manner of operation for manually 19 disengaging the gear. Again, this type of manual operation can be adapted as appropriate to the embodiments of Figures I I to 14.

Other features of the embodiments described above form the subject of patent application No. 9720109.9 (Serial No. 2 318 395) from which this application is divided.

Claims (18)

1. An actuating device for an output member movable with two kinds of motion for actuating a motor vehicle, the device including at least one actuating drive for the output member, in which a single actuating drive operates the output member for both kinds of motion, and a switching mechanism operates to switch the output member between operation in the two kinds of motion and to predetermine the position of the output member for one kind of motion.

2. An actuating device as claimed in claim 1, in which the switching mechanism predetermines the position of the output member for selecting the gearbox selector lane, and the other kind of motion is used to select the ratio in the lane.

3. An actuating drive as claimed in claim 1 or claim 2, in which the switching mechanism includes a locking element having a first claw which locks the output member against axial movement by engaging without axial clearance in a first recess in the output member and a second claw which locks the output member against angular movement by engaging without circumferential clearance in a second recess in the output member.

4. An actuating device as claimed in claim 3, in which a number of first recesses are associated with the first claw, each recess defining a selector lane of the gearbox.

5. An actuating device as claimed in claim 3 or claim 4, in which the second claw of the locking element remains in the second recess, and to release its locking is movable into a position in which it has circumferential 21 clearance in the second recess to allow angular movement of the output member.

6. An actuating device as claimed in claim 3 or claim 4, in which the second recess comprises a slot, and locking is released by moving the second claw to a position on the axis of rotation of the output member to allow angular movement.

7. An actuating device as claimed in any preceding claim, in which the actuating drive is connected to the output member through helical teeth.

8. An actuating device as claimed in any preceding claim, in which the actuating drive has an overload protection means which is activated on faulty control of the drive to prevent transmission of the driving movement of a gearing element on reaching a stop associated with this gearing element.

9. An actuating device as claimed in claim 8, in which the overload protection means comprises a slipping clutch which is activated on continuing motion of the drive in contact with a stop in the prevailing direction of movement.

10. An actuating device as claimed in claim 8, in which the overload protection means includes resilient elements which, when predetermined positions of the gearing element are reached deform elastically in opposition to the force from the drive to damp the movement of the gearing element.

11. An actuating device as claimed in any preceding claim, in which electric motors are used as the actuating drives.

22

12. An actuating device as claimed in any preceding claim, including a flange by which it is mounted on a gearbox, the flange also providing a mounting for additional elements.

13. An actuating device as claimed in claim 12, in which the flange has at least one opening for the introduction and removal of gearbox oil, which is closed by means of a closure element as the first additional element.

14. An actuating device as claimed in claim 12 or claim 13, in which the flange has openings for further additional elements such as sensors.

15. An actuating device as claimed in any preceding claim, in which the actuating drive is provided with a device which allows manual actuation of 15 the output element of the drive.

16. An actuating device as claimed in claim 15, in which the actuating drive has a device by which a motor spindle of the drive rigidly connected to the output element is operable manually.

17. An actuating device as claimed in claim 16, in which the motor spindle has at its end a profile engaged by a complementary profile of an actuating element used for manual operation.

18. An actuating device for an output member movable with two kinds of motion for actuating a motor vehicle gearbox of the kind set forth substantially as described herein with reference to and as illustrated in any of Figures 11 to 14 of the accompanying drawings.