FR2839132A1 - Actuator for automatic gearbox, comprises self locating selection actuator which may use stepping motor with convertor to linear motion or linear drive using permanent magnets and variable reluctance - Google Patents

Abstract

An operating finger (115) moves in translation to select forks (110) and rotates to engage them. The translation and selection is effected by a linear motor (130) with position sensor (140) and spindle (117). Rotation and gear engagement is produced by a second motor (120) using pinions (122,123,124,125) and a sleeve (118) which is locked in rotation with the spindle but may slide along it Independent claims are also included for the following : 1) An actuating mechanism of the translating and rotating arm type which uses a self locating selection drive such as a stepping or linear motor 2) An automatic gearbox which uses the self locating selection drive

Description

preceding. The present invention relates to an actuator for a box

  robotic gearbox, and a gearbox

  robotisoe gears comprising such an actuator.

  A traditional gearbox includes a gear change mechanism, cooperating with a

release mechanism.

  In a robotic gearbox, gear changes are made by electric actuators,

  hydraulic or electro-hydraulic.

  For example, with reference to FIG. 1, a gearbox 1 comprises forks 10 arranged side by side.

  rib and corresponding to dogs.

  Each range corresponds to a speed line.

  For a five-speed gearbox and reverse like that shown in Figure 1, a first fork allows, depending on whether it is moved in one direction or the other, the engagement of the first or second speed, a second fork allows engagement of third or fourth gear and a third fork allows engagement of fifth gear or

reverse gear.

  A control finger 15 can be moved transversely between the forks 10 for the

selection of a speed line.

  Once the finger 15 is positioned in the plane of the fork which corresponds to the dog that we want to move, it can be moved in the plane of this

  fork in order to engage a gear.

  Electric, hydraulic or electrohydraulic actuators can be used to control on the one hand the transverse movement of the finger 15, that is to say the selection movement, and on the other hand the movement in the plane of a fork 10 of the finger 1,

  ie the movement of engagement.

  Devices with electric actuators for actuating a gearbox control finger known in the prior art use two electric actuators acting on a control shaft at the end of which is mounted the control finger. The control arUre can rotate around its axis and translate along this axis. A selection actuator controls the translation of the control shaft and an engagement actuator controls the rotation of this

Arure.

  An example of a device with electric actuators

  known type is shown in Figure 2.

  The control finger 15 is mounted at the end of a control arUre 17 which can rotate about its axis and translate along this axis. The arUre 17 extends perpendicular to the plane of a fork 10. The finger extends radially with respect to the arUre 17 and, by

  Therefore, in the plane of a range 10.

  An actuating device 40 comprising a selection actuator and an engagement actuator

  controls the translation and rotation of the shaft 17.

  Milling means 20 keep the shaft 17 in a speed line selection position. These means include a ball mounted at one end of a deformable support such as a spring, the other end of which is fixedly mounted in the gearbox. Notches 30 are provided on the control arUre 17 at a regular interval corresponding to the spacing

between two forks 10.

  There are as many notches on the tree 17 as there are

forks 10.

  These notches are positioned to correspond to the line selection positions of

finger speed 15.

  In a position for selecting the speed line of the finger 15, the billing ball 20 is in a notch 30 and thus makes it possible to hold the arUre 17 in position. When the selection actuator exerts a force on the shaft 17, this force, transmitted by the inclined slope of the notch 30 on which the ball carries, is sufficient to cause a deformation of the deformable support of the billing 20, and, by Therefore, the

  release of the ball from this notch 30.

  Milling 20 serves in particular, during a speed change operation, to maintain the fixed control finger in tranelation before and after the step of selecting

  speed, when no speed is engaged.

  This avoids an unexpected displacement in translation of the control finger, due, for example, to the passage of a vehicle on a terrain accident such as a "nest of

hen ".

  The selection actuator must be able to provide sufficient force to release the holding ball. This involves the use of an actuator which can develop a large force, which has the consequence

  a significant size and cost of the actuator.

  In addition, the actual billing occupies a significant place in the gearbox and has itself a

certain cost.

  The present invention aims to eliminate these drawbacks. This object of the invention is achieved with a selection actuator for a robatisoe gearbox control shaft, remarkable in that it comprises means for indexing the selection positions of said control shaft. Thanks to the indexing means of the selection actuator, we can do without billing, and it is therefore no longer necessary to have an actuator sufficiently

  powerful to overcome the resistance of such billing.

  In this way we can reduce the size and cost

  compared to the devices of the state of the art.

  According to other characteristics of the actuator according to the invention: said actuator is of the stepping type, - said actuator is of the linear type with permanent magnets,

- said actuator is controlled.

  An actuator of the stepping type being characterized by a limited number of stable positions each corresponding to a position for selecting the control shaft, it makes it possible to ensure the maintenance of the drive shaft.

  control in these stable positions.

  The present invention also relates to a device for actuating a robotic gearbox, of the type comprising a control shaft, means for translating said control arUre in order to select a gear shift fork, and means to rotate said control shaft in order to engage said gear shift fork, remarkable in that the said translation means comprise a selection actuator conforming to the above. The present invention also relates to a robatisoe gearbox, remarkable in that it comprises an actuating device in accordance with the above. Other features and advantages of this

  invention will appear in the light of the description which

  will follow and on examining the appended drawing, in which: - Figure 1 is a simplified view in perepective representing certain elements of a robotic gearbox of the state of the art, - Figure 2 is a simplified view in perspective representing a state-of-the-art actuation device for the robotic gearbox of FIG. 1, FIG. 3 is a block diagram simply representing a first embodiment of a actuation according to the invention, - Figure 4 is a representation with block diagram and partial schematic perspective view of an example of an actuating device according to Figure 3 cooperating with a robotisce gearbox, - Figure 5 is a block diagram showing in a simplified manner a second embodiment of an actuating device according to the invention, and - Figure 6 is a schematic front view of a

linear actuator.

  In these figures, identical or analogous references designate organs or assemblies of organs

identical or analogous.

  An actuating device according to the invention applies to a robotized gearbox like that

  described with reference to Figure 1.

  As in the prior art actuation device, shown in FIG. 2, the control finger is mounted at the end of a control arU which can rotate around its axis and translate along

of this axis.

  A selection actuator controls the translation of the control arUre and, consequently, the movement of

selection of the control finger.

  An engagement actuator controls the rotation of the drive shaft and, therefore, the movement

of engagement of the control finger.

  The present invention mainly relates to the operation of the selection actuator. This involves keeping the control finger fixed in translation before and after a translational displacement step of said

  finger, when no gear is engaged.

  A sequencing of the operation of the actuating device for a speed change operation may comprise the following steps: a declutching step, a step of maintaining the position of the control arUre, a step of disengaging the engaged gear, a step change of speed line, a speed engagement step, a hold stop step in

  position of the control shaft and a clutch step.

  The stages of clutching and disengaging are well known and will not be described in detail here. The stages of engagement and disengagement of speed

  mainly concern the engagement actuator.

  The steps for changing the speed line, keeping the shaft in position and stopping the holding in the rear position mainly concern the actuator

Selection.

  The selection actuator is only requested during gear changes so that its consumption remains

low.

  FIG. 3 shows in a simple manner a first embodiment of an actuating device

according to the invention.

  A control element 105 makes it possible to control the engagement actuator 120 and the selection actuator, the said actuators 120 and 130 making it possible to actuate the control rod 117 and therefore the control finger by means of a mechanism of

transmission 150.

  A position sensor 140 is associated with the selection actuator 130. This sensor can be integrated into the transmission mechanism 150 or directly on the rear.

117.

  In all cases, this sensor makes it possible to give information on the position of the control shaft 117, and therefore to carry out a shaky chain control of

the selection actuator 130.

  The control element 105 provides a position setpoint corresponding to the desired position for

the control arT 117.

  The position setpoint is compared to the position

  mesurse by the position sensor 140.

  This results in an effective command transmitted to the selection actuator 130 aimed at reducing the difference between the position setpoint and the measured position. This loose chain control mode makes it possible to maintain the position of the control arUre 117 after the disengagement of a speed, the change of speed line movement and the maintenance in position of the control arUre before l engagement of a new speed. The control element 105 emits a position instruction corresponding to the position of the current speed line before the speed disengagement step. At the speed line changing step, the control element 105 changes this position setpoint to a position setpoint corresponding to the

  position of the new speed line.

  The control element 105 maintains the new position setpoint until the end of the step

of engagement of new speed.

  The position hold stop step corresponds to the end of the supply of the selection actuator 130. The position of the control shaft 117 is therefore maintained by servo-control of the selection actuator

in the desired position.

  In this first embodiment, the engagement 120 and selection actuators 130 may include

  both rotary electric motors.

  However, the selection actuator 130 can also be a direct-drive linear electric actuator, that is to say an electric actuator which

  directly controls linear motion.

  In this case, it is then not necessary to use a mechanism for transforming rotary movement into

linear movement.

  FIG. 4 shows an actuation device of this type, that is to say comprising an engagement actuator 120 comprising an electric motor, and a selection actuator 130 constituted

  by a direct drive linear electric actuator.

  As in the device of the state of the art represented in FIG. 2, the control finger 115 is mounted at the end of a control shaft 117 which can rotate around its axis and be tranelated along this axis. The control shaft 117 is mounted coaxially in an engagement arue 118 of which it is integral in rotation

  but with respect to which it is free in translation.

  The control shaft 117 is integral in translation with the linear actuator 130, but it is free in

rotation with respect to the latter.

  Each of the stable positions of the linear actuator 130 corresponds to the selection of one of the

forks 110.

  A position sensor 140 is associated with the selection actuator 130. The measured position is sent to control electronics 105 allowing piloting in

  shifted chain of the selection actuator 130.

  The engagement actuator 120 comprises a rotary shaft motor 121 carrying at its end a pinion 122 engaged with a toothed wheel 123 on which is ccaxially mounted a pinion 124 engaged with a toothed wheel which controls the rotation of the arUre engagement 118

  and, consequently, of the control shaft 117.

  The engagement actuator 120 is controlled by

the control electronics 105.

  FIG. 5 is a simplified representation of a second embodiment of a device

actuator according to the invention.

  A control electronics 205 makes it possible to control the engagement actuator 220 and the selection actuator 230, the said actuators 220 and 230 making it possible to actuate the control shaft 217 and therefore the control finger by means of a mechanism

transmission 250.

  In this embodiment, the selection actuator 230 is a stepper actuator, that is to say an actuator adapted to move between a certain number of stable positions separated from each other by a

  same distance corresponding to the pitch of the actuator.

  The actuator 230, of the step-by-step type, has a pitch corresponding to the spacing between two forks and a number of stable positions corresponding to the total number

of forks.

  Due to the characteristics of the actuator 230, the control of this actuator can be done in an open chain. The control electronics 205 provides a position control corresponding to the current speed line

  before the speed disengagement step.

  This command ensures that the actuator 230 remains in the stable position corresponding to the current speed line. At the time of the speed line change step, the control electronics 205 changes this position command and replaces it with a command of

  position corresponding to the new speed line.

  The control electronics 205 maintains the new position control until the end of the step

of engagement of new speed.

  The position hold stop step corresponds to

  the end of the selection actuator supply.

  Maintaining in position, according to this embodiment, is therefore achieved by the presence of stable positions of the actuator corresponding to the speed lines. In this second embodiment, only the actuator

  engagement 220 includes a rotary electric motor.

  The selection actuator may, for example, be a linear stepper actuator with permanent magnets or with

variable reluctance.

  FIG. 6 schematically represents an embodiment of a linear actuator with direct drive of the type

step by step with variable reluctance.

  As can be seen in this figure, this actuator 330 comprises a fixed part 331 and a movable part 332

  sliding inside the fixed part.

  The control area of the control finger is

  secured in translation of the movable part 332.

  The fixed part 331 comprises a plurality of coils 333, 334, 335, 336 the number of which corresponds to the number of

stable actuator positions.

  In the embodiment shown, these coils are four in number. It is therefore an actuator with

  three steps which therefore has four fixed positions.

  The coils are arranged one after the other, alternately above and below the movable part, so that the zone separating two

  coils is next to another coil.

  The movable part 332 is made of metallic material and includes teeth of dimensions

  substantially corresponding to those of the coils.

  When a coil is supplied, a magnetic field is generated, exerting on the moving part. 332 a force tending to attract the two teeth of the movable part 332 closest to the coil supplied in line with this coil. For example, the position shown in Figure 6 is controlled by the supply of the coil 333. If the coil 333 is no longer supplied and the coil 334 is supplied, the coil 334 will attract the two teeth of the movable part 332 which will be placed at the right of this coil, causing a displacement of the part

332 mobile one step.

  The movements of the mobile part 332 and therefore of the control arUre are ensured by current injection

in a reel.

  Maintaining the position of the movable part and therefore of the control shaft are ensured by maintaining the

current in this coil.

  The sequencing can therefore be that described above. Therefore, the selection actuator

  is only used during gear changes.

  Of course, the present invention is not limited to the embodiments described and shown, supplied to

  illustrative and non-limiting example.

  For example, other stepper actuators than a linear actuator could be used,

  such as rotary stepper actuators, for example.

Claims (6)

REVENDI CAT IONS   1. Selection actuator (130; 230; 330) for control shaft (117; 217) of robatisoe gearbox (1), characterized in that it comprises means for indexing the selection positions of said control arUre. 2. Actuator (230; 330) according to claim 1,   characterized in that it is of the step-by-step type.   3. Actuator (330) according to claim 2, characterized in that it is of the linear magnet type   permanent or variable reluctance.   4. Actuator (130) according to claim 1,   characterized in that it is enslaved.   5. Device for actuating a robotic gearbox, of the type comprising a control shaft (117), means (130, 140) for translating said control shaft in order to select a gear shift fork (10 ), and means (120 to 125) for pivoting said control shaft (117) in order to engage said gear shift fork (10), characterized in that said translation means comprise a selection actuator (130 ) in accordance with any of claims 1 to 4.   6. Robatisse gearbox, characterized in that it includes an actuating device in accordance with