FR2861154A1 - Gear change actuator for vehicle gearbox includes electronically controlled motor with threaded shaft displacing output actuator - Google Patents

Abstract

The device provides reversible action for moving gear selection components under electronic control. The control assembly for a robot-controlled gearbox comprises at least one actuator (A1) for shifting or selecting gears, and a power electronics unit for controlling the actuator. The actuator comprises an electric motor (M1) and a system (ST1) for transforming the rotation movement of the motor output shaft into a linear movement which is transmitted to an output element (T1). The movement transformation is achieved by a threaded shaft (10) which is driven via toothed wheels (12) by the motor, and a travelling element (15) running on the threaded shaft and fastened to the movement transmission device (DT1).

Description

The invention relates to a control assembly for a gearbox

robotized motor vehicle.

  In general, such a control assembly comprises two actuators for passage and selection of gear ratios, and a power electronics for driving the two actuators.

  Each actuator comprises in particular an electric motor which is driven by the power electronics, and a system for converting the rotational movement of the output shaft of the motor into a translation movement which is communicated by a motion transmission device: to a control element of the gearbox.

  According to US-A-4,440,035, the motion transformation system is constituted by a screw-nut assembly, the screw being coupled to the output shaft of the motor and mounted parallel thereto, while the fixed nut in rotation but mobile in translation is connected to the control element of the gearbox.

  An object of the invention is in particular to improve such actuators to increase the efficiency and make their operation very reversible, while having other advantages.

  For this purpose, the invention proposes a control unit for a robotised gearbox of a motor vehicle, comprising at least one actuator for passage and / or selection of gear ratios, and a power electronics for driving the actuator. , said actuator comprising in particular an electric motor and a system for converting the rotational movement of the output shaft of the motor into a translation movement which is communicated by a motion transmission device to an output member of the actuator for controlling the gearbox, the motion transformation system comprising a threaded shaft coupled to the output shaft of the motor and a movable member in translation which is in contact with the threaded shaft and connected to the motion transmission device which includes an elastic connection, a control assembly which is characterized in that the device for transmitting movement of the element rolls the output element of the actuator comprises an input element which is integral with the rolling element, and an output element guided in translation and integral with the output element of the actuator, the elastic connection. being formed of a spring mounted in axial support between the input and output elements. The mounting of a single spring axially supported between all the input and output elements of the motion transmission device is simpler and less expensive than in the known art and makes work the spring under more favorable conditions, increasing thus its service life.

  Advantageously, the spring is supported at each of its ends on an axial portion of one of the input and output elements and on two parts symmetrical with respect to the axis of the spring of the other of the input elements and Release.

  This ensures the axial support of the spring at its ends on the input and output elements.

  According to an exemplary embodiment of the invention, the thread of the shaft of the motion transformation system is at constant pitch, and the translational member which is in contact with the threaded shaft is a ball screw, a ball bushing or the like.

  According to another exemplary embodiment of the invention, the threading of the shaft of the motion transformation system is at variable pitch.

  Advantageously, the thread of the shaft of the motion transformation system has a larger pitch in its central part than towards its two ends, and the rolling element 30 which is in contact with the threaded shaft is a rolling pin having a frustoconical shape, in roll or in ogive.

  The control assembly and its power electronics are supported by a housing including a body and a cover, said cover being advantageously used to secure the housing to the interior of the engine compartment of the vehicle.

  The actuator of the control assembly is associated with at least one position sensor which may be of the linear or rotary type.

  Advantageously, there is provided in the actuator a protection device to overcome a: failure of the control electronics which would result in an absence of braking of the drive motor when the actuator reaches the end of the race, this protection device which can be constituted by an absence of threading at each end of the shaft when the threading of the shaft is variable pitch, or by a torque limiter when the threading of the shaft is at constant pitch.

  The rotational support of the threaded shaft of the actuator can be provided by bearings or, more economically, by bearings which are associated with axial stops, the latter being able to be arranged to perform a function initial adjustment of the axial clearance of the threaded shaft, absorption of shocks and expansions, and / or recovery of axial forces with a minimum of friction.

  In a general way: - the drive motor shaft and the actuator threaded shaft are parallel to each other or axially aligned with each other, and - the elements of input and output of the actuator motion transmission device extending parallel to the threaded shaft or are coaxially mounted to said shaft.

  According to a first embodiment, the control assembly comprises two actuators for the selection and the passage of gear ratios, these two actuators having generally the same structure, that is to say with a system of transformation of movement to rolling pin, and the drive shaft, the threaded shaft and the sliders of the actuator which extend parallel to each other.

  According to a second embodiment, the control unit differs from the previous one in that the motion transformation system comprises a ball bushing.

  According to a third embodiment, the two sliders of the actuator are mounted coaxially with the threaded shaft, which in particular makes it possible to reduce the friction forces.

  According to a fourth embodiment, the control assembly comprises only one actuator whose = The output element forms a control shaft which is movable both in rotation to select the rank of the report to engage and in translation to engage the selected gear, the rotational movement being obtained from a second motor.

  A control assembly according to the invention has many advantages, the main ones of which are listed below.

  The use of a rolling member associated with the threaded shaft of the motion transformation system in each actuator optimizes the operation of the associated motor and therefore the performance of the actuator.

  The use of a rolling body of the. type pin or roller also allows to have an asymmetric mounting and reduce the distance between the motor shaft and the threaded shaft of the motion transformation system, and it results in a smaller footprint than in the case of a ball bushing which is mounted coaxially with the threaded shaft.

  In addition, a rolling member of the peg or roller type can advantageously cooperate with a threaded shaft with variable pitch, while this step is necessarily fixed in the case of a ball bushing.

  Moreover, the use of a threaded shaft with variable pitch, in particular a thread with small pitch towards both ends of the threaded shaft and a larger pitch in its central part, makes it possible to limit the power consumption required by the motor. to maintain the end position of the actuator, in particular for the passage actuator.

  When the actuator is at the end of the stroke, it is in the synchronization phase with the compressed elastic connection to have a maximum synchronization effort with a small pitch thread.

  In addition, the use of a peg or rolling roller is less sensitive to solid pollution than a bushing or ball screw, is simpler structure, easier assembly and lower cost.

  Finally and in a general manner, a control assembly according to the invention with one or two actuators is designed taking into account a division of the different constituent elements according to those which can be considered as standard elements and those which are specific to a given application depending on the type of vehicle for example.

  In fact, gearbox controls implement different operating principles (rotary, rotalinear, etc.), and it is difficult to design generic actuators.

  The invention also aims to achieve this goal by providing a control assembly in which the actuator consists of: - at least one standard subassembly with a plastic housing, input and output slides which are guided in the housing, at least a slider position sensor, a linear motion transformation system with a rolling element, and a single spring mounted in axial support between the two sliders, for example, and - elements or components specific to each application , such as the motorization including the gearbox, the power electronics that controls the actuator, the output interface of the actuator, for example.

  Other advantages, features and details of the invention will emerge from the additional description which will follow with reference to the accompanying drawings, given solely by way of example and in which: FIG. 1 is a partial perspective view of a 2-actuator control assembly according to a first embodiment of the invention; FIG. 2 is a cross-sectional view of the control assembly illustrated in FIG. 1; FIG. 3 is a sectional view as follows; line III-III of FIG. 2; FIG. 4 is a sectional view to illustrate a variant of a detail of FIG. 3; FIG. 5 is a schematic sectional view to illustrate a variant of FIG. Figs. 6a-6c are sectional views for illustrating a mechanism for protecting the actuators; Fig. 7 is a sectional view for illustrating a torque limiter associated with the threaded shaft of the actuators; Figs. 8a-8g are sectional views for illu FIG. 9 is a partial perspective view of a control assembly according to a second embodiment of the invention; FIG. 10 is a top view of the actuator shaft of the actuators; FIG. FIG. 9 is a sectional view along the line XI-XI of FIG. 10, FIGS. 12 and 13 are two partial sectional views to illustrate two embodiments of the housing of the assembly of FIG. FIG. 14 is a partial sectional view of a third embodiment of the control assembly according to the invention, and FIGS. 15 and 16 are perspective views of a fourth embodiment of FIG. a control assembly according to the invention.

  Referring firstly to Figures 1 to 3 which illustrate a first embodiment of a control assembly E for a robotized gearbox of a motor vehicle.

  This control assembly E comprises two actuators A1 and A2 for passage and selection of reports of the gearbox. Each actuator A1 and A2 comprises in particular an electric motor M1 or M2, and a system ST1 or ST2 for converting the rotational movement of the output shaft of the motor M1 or M2 into a translation movement which is communicated by a device DT1 or DT2 for transmitting motion to an output member of the associated actuator, such as a Ti or T2 rod for controlling the gearbox (not shown).

  The actuator A1 will be described hereinafter as, in this first embodiment, the actuator A2 is in every respect similar to the actuator A1.

  The motion transformation system ST1 of the actuator A1 comprises a threaded shaft 10 which is rotatably coupled to the output shaft of the motor M1 by means of a gear train 12, and an element 15 (FIGS. 3) which is movable in translation and in rolling contact with the helical groove formed by the threading of the threaded shaft (10).

  The motion transmission device DT1 comprises an input slider 18 which is integral with the rolling element 15 of the motion transformation system ST1, an output slider 20 which is fixed to the output shaft T1 of the actuator Al , and an elastic connection R or energy accumulation which is interposed between the two slides 18 and 20.

  The axis X1-X1 of the motor M1, the threaded shaft 10 and the output shaft T1 of the actuator A1 extend parallel to one another.

  In general, the rolling element 15 which is in contact with the threaded shaft 10 may consist of: - either a screw or a ball bush which can cooperate only with a threaded shaft 10 whose thread is fixed pitch, - either by a pin or roller roller which can advantageously cooperate with a threaded shaft 10 whose thread is fixed pitch or variable.

  In this first embodiment, the rolling element 15 is constituted by a pin P which, with reference to FIG. 3, is partially fitted into the inner race 22a of a bearing 22 whose outer race 22b is integral with the slide. Inlet 18. Tua outer cage 22b of the bearing 22 (Figure 3) is fixed to the input slider 18. Thus, the rotation of the threaded shaft 10 causes the translational movement of the rolling pin P and the slider 18 in a direction which is a function of the direction of rotation which is impressed on the threaded shaft 10 by the motor M1.

  The pin P can be made of rolled metal, machined, sintered, molded, stamped or forged, the conical head of which in FIGS. 2 and 3 can have a barrel shape, as illustrated alternatively in FIG. 4, or in the form of an ogive.

  In FIGS. 2 and 3, the rolling pin P and the motor M1 are situated on either side of the threaded shaft 10. In a variant, as is schematically illustrated in FIG. 5, the rolling pin P can be located above the threaded shaft 10. It is sufficient for this purpose to change the shape of the input slider 18 in a suitable manner.

  Thus, the use of a rolling pin P makes it possible to reduce the axis-to-axis shaft spacing 10-motor Ml and thus the size of the actuator, compared with the use of a ball bushing coaxially mounted to the threaded shaft 10.

  The elastic connection R interposed between the two sliders 18 and 20 is constituted by a helical spring for example which can be prestressed and which bears axially at its ends on the sliders. In the embodiment of FIG. 2, the outlet slide 20 comprises, at each end of the spring R, a radial tab passing through the axis of the spring and on which the end turn of the spring rests in two zones. diametrically opposite, and the input slider 18 comprises two radial tabs symmetrical with respect to the axis of the spring and on which the said end turn of the spring rests.

  Referring to FIG. 3, one end of the output shaft T1 of the actuator A1 protrudes inside a blind hole 23 formed in the outlet slide 20, and it is fixed to the slide 20 by a rotatable connection 24 located in the bottom of the hole 23, knowing that any other fastening means could be envisaged.

  When the motor Ml of the actuator A1 is turned on, the rotational movement of the threaded shaft 10 causes a simultaneous movement in translatio: z of the rolling pin P and the input slider 18. If the output rod Tl the actuator A1 is not subjected to any resistant force, the displacement of the input slider 18 drives that of the output slider 20 through the elastic connection R which undergoes no deformation by axial compression. On the other hand, in the presence of a resisting force at the output rod T1, the displacement of the input slider 18 will cause the elastic connection R to be compressed axially without causing the output slider 20 to move. the disappearance of this. resisting force, which corresponds to the passage of the synchronization wall, the energy stored by the elastic connection R is released thereby causing the displacement of the output slide 20.

  The threaded shaft 10 of the actuator A1 is rotatably coupled with the output shaft of the motor M1 by the gear train 12 which comprises at least two spur gears or bevel gear possibly forming a speed reducer. The threaded shaft 10 is rotatably supported by means of a ball bearing 25 (FIG. 3) which makes it possible to ensure good recovery of the radial forces generated by the gears of the gear train 12 and also makes it possible to improve the efficiency of the actuator A1.

  In general and referring particularly to Figure 2, the control assembly E is partly housed in a housing or housing 30 which consists of a body 30a and a cover 30b. The respective motors M1 and M2 of the actuators A1 and A2 are mounted outside the body 30a of the housing 30, while the rest of the constituent elements of the actuators A1 and A2 is housed inside the body 30a. Advantageously, the body 30a of the housing 30 is generally split into two housings which respectively receive the two actuators A1 and A2. The power electronics EP which drives the two actuators A1 and A2 form a subassembly which is also supported by the housing 30, outside thereof.

  Referring to Figures 1 and 2, the two slides 18 and 20 have grooves 32 which extend parallel to the axis of the threaded shaft 10. These grooves 32 receive corresponding ribs 33 which project from the face internal of the body 30a of the housing 30 for supporting and guiding the slides 18 and 20.

  When the actuator A1 is in operation, the motor M1 drives the input sliders 18 and output 20, and brakes at the end of the race.

  However, in the case of an erroneous command provided by the power electronics EP and: which would not cause the motor Ml to stop, the shock of the actuator A1 must be dampened when it comes to a stop on the casing 30 to not damage anything.

  For this purpose, there is provided a mechanical protection device which will be explained below with reference to Figures 6a-6c.

  The front and rear faces of the output slide 20, considering its direction of movement, have a portion which projects from the corresponding front and rear faces of the input slide 18, this projection 20a forming a stop 20a (FIG. ).

  Thus, when the stop 20a of the output slide 20 has come into contact with the casing 30 (FIG. 6b), the motor M1 continues to rotate by driving in translation the input slide 18 but with concomitant axial compression of the elastic link R However, the thread is interrupted at each end 10a of the threaded shaft 10 in order to be able to disengage the motion transformation system ST1 while the motor M1 is rotating. More specifically, the thread of the threaded shaft 10 is interrupted over a length such that the input slider 18 can not come into abutment on the housing 30 (Figure 6c) even if the motor Ml continues to rotate.

  Finally, the deformation race of the elastic link R must be large enough so that it can then, after stopping the motor M1, reengage the rolling pin P in the thread of the threaded shaft 10.

  On the other hand, when the rolling element 15 of the motion transformation system is constituted by a ball screw, it is not possible to interrupt the threading of the threaded shaft 10 at each of its ends. In this case, it is possible to use a torque limiter, as shown in FIG. 7, which is calibrated at a torque greater than the maximum normal operating torque. This torque limiter 32 can be advantageously produced by means of a so-called tolerance ring which is mounted on the drive shaft or the drive shaft of the ball screw.

  According to a more economical embodiment than ball bearings, the threaded shaft 10 can be rotatably supported by bearings such as cylindrical or swivel bearings, with the presence of axial contact abutments of the sphere / plane type at the ends of the threaded shaft 10, as will be described hereinafter on various examples illustrated in Figures 8a-8g.

  In all these examples, the threaded shaft 10 is rotatably supported by rotatable bearings 33, knowing that the stops which make it possible to continuously compensate for the axial clearance of the threaded shaft 10 can be arranged with different arrangements depending on whether the it is also desired to have a device for initially adjusting the axial clearance of the threaded shaft 10, an elastic device for absorbing shocks or expansions, and / or a device for taking up the axial forces with a minimum of friction. Indeed, all these devices can be combined with each other.

  An assembly with an adjusting device D1 of the axial play of the threaded shaft is illustrated in FIG. 8a, with a variant illustrated in FIG. 8b.

  In the example of FIG. 8a, the axial abutment B at each end of the threaded shaft 10 is constituted by two balls b1 and b2 made of steel and of the same diameter which are housed in an axial blind hole 35 machined at the end. end of the threaded shaft 10, and by a set screw 37 of treated steel which can bear on the balls b1 and b2, knowing that the depth of the blind hole 35 which receives the balls is less than twice the diameter of the balls to make a contact of the sphere / plane type. Once the adjustment is made, the screw 37 is immobilized by gluing, for example. According to the variant of Figure 8b, the adjusting screw 37 is replaced by a washer 38 of treated steel which comes into contact with the balls, and by a resin plug 39 which, after solidification, bears on the washer 38.

  An assembly with a device D2 for absorbing shocks and expansions is illustrated in FIG. 8c, with a variant illustrated in FIG. 8d.

  In the example of FIG. 8c, the axial abutment B is formed by each end face of the threaded shaft 10 which is curved to obtain a contact of the sphere / plane type with a washer 38 of treated steel which is wedged to the by means of an elastomer stud 40. According to the variant of FIG. 8d, the washer 38 is of convex shape and the elastomer stud is removed.

  An assembly with a device D3 for taking up the axial forces with a minimum of friction is illustrated in FIG. 8e, with two variants illustrated in FIGS. 8f and 8g.

  In the example of FIG. 8e, the axial abutment B at each end of the threaded shaft 10 is constituted by a curved shape of the end face of the threaded shaft 10, and by a set screw 37 which is mounted as in the example of Figure 8a. According to the variant of Figure 8f, the curved faces of the end faces of the threaded shaft 10 are replaced by tips 41 reported in the form of T. Each errbout 41 comprises a rod 41a fitted into a blind hole 42 machined at each end of the threaded shaft 10, and a domed head 41b which comes into contact with the adjusting screw 37. The tips 41 may be made of plastic or cold-stamped steel. According to the variant of FIG. 8g, the axial abutment B at each end of the threaded shaft 10 is constituted by two balls b1 and b2, as in the example of FIG. 8a, and by an elastomer stud 40 which replaces the set screw.

  In general, the two actuators A1 and A2 also comprise at least one position sensor which will be described later. A second embodiment is. illustrated in FIGS. 9 to 11, but the representation of the control assembly E has been deliberately limited to a single actuator, for example the actuator A1. In this second embodiment, the rolling element 15 which is associated with the threaded shaft 10 of the motion transformation system ST1 is constituted by a ball bushing D which involves a thread with fixed pitch for the threaded shaft 10. This bush D is mounted coaxially with the threaded shaft 10, and it resulting in a larger footprint than in the case of the rolling pin P of the first embodiment.

  This second embodiment makes it possible to illustrate another structure for the two slides 18 and 20 of the actuators A1 and A2.

  The inlet slider: L8 associated with the ball bushing D is constituted by two stamped sheet metal parts 45 which are arranged parallel to one another and connected by columns 47, leaving between them an interior space (FIGS. 9 and 11). The posts 47 are fixed to the plates 45 by crimping, for example. The space between the two sheets 45 is generally split into two parts by means of a fixed inner partition 48 which extends parallel to the threaded shaft 10 of the motion transformation system ST1.

  On the side adjacent to the motor Ml, the two plates 45 each have an opening 50. These two openings 50 facing each other delimit a housing which traps the ball bushing D. On the side adjacent to the output rod Tl of the actuator, the two plates 45 delimit between them a housing inside which is mounted the outlet slide 20 which is in the form of a frame 55 having a central opening 57. The two plates 45 of the slide 18 each have an opening 59 located generally facing the opening 57 of the frame 55. These openings 57 and 59 form the housing of the spring R between the two slides 18 and 20.

  The output shaft T1 of the actuator A1 is made integral with the frame 55 of the outlet slide 20 by fastening means 62. The rod Ti is in the form of a plate which extends parallel to the threaded shaft 10 and slides in a guide groove 68 formed in the housing 30.

  In general, each actuator A1 and A2 is equipped with at least one position sensor which can be positioned either at the output shaft of the motor M1 or at the slides 18 and 20. In the embodiment shown in Figure 11, there are provided two sensors 70 which are respectively associated with the sliders 18 and 20 to give information on the position of the actuator or the gearbox, as well as the level of effort applied .

  These two sensors 70 comprise two contacts 70a respectively carried by the two slides 18 and 20. These two contacts 70a are situated on either side of the fixed partition 48 and respectively come into contact with two conductive tracks 70b carried by the partition 48. .

  The sensors 70 shown in FIG. 11 are of the linear type but, alternatively, rotary type sensors could be used.

  As for the first embodiment, the control assembly E is supported by a housing 30 with the motors M1 and M2 located outside the housing, while the other components of the actuators A1 and A2 are housed inside. of the housing 30. The fixed partition 48 which is located between the two sheets 45 of the input slider 18 is integral with the housing 30 and forms a means for guiding the sliders 18 and 20.

  Of course, in this second embodiment, one could replace the ball bushing D with a rolling pin P and adapt accordingly the structure of the input slider 18.

  Figures 12 and 13 illustrate an exemplary embodiment of the housing 30 which supports the control assembly E, this example can be applied to the two embodiments described above.

  In general, the casing 30 is fixed inside the engine compartment of the vehicle, this fixing being able to be performed at its body 30a or its cover 30b.

  In Figure 12, the housing 30 is fixed at its body 30a by means of screws or bolts through holes 30c drilled in a peripheral rim of the body 30a. By cons, in Figure 10, the fixing of the housing 30 is formed at its lid 30b which have holes 30c pierced in a peripheral rim of the lid 30b. Providing the fixing points of the housing 30 at its cover 30b, has the advantage of allowing an interchangeability of said cover according to the different vehicles while maintaining the same housing body.

  Figure 14 schematically illustrates a third embodiment of the control assembly E according to the invention.

  This third embodiment essentially differs from the two modes described above by the fact that the control assembly shown comprises only one actuator A1 and that the two slides 18 and 20 are mounted coaxially with the threaded shaft 10. rolling element 15 which cooperates with the threaded shaft 10 is a ball bushing D in the illustrated example. This third embodiment makes it possible in particular: to reduce the friction forces during movement of the slides, which results in a better efficiency of the actuator, and provides a more compact assembly.

  The input slider 18 is in the form of a sleeve 80 in which the threaded shaft 10 engages, which cooperates with a screw socket D integral with the sleeve 80. The outer periphery of the sleeve 80 has two shoulders 82 and 84 which delimit between them a peripheral groove 86.

  Two washers 88 are attached around the sleeve 80 and a spring R, so that the spring comes to be housed in the groove 86 by resting on the two washers 88 which are respectively wedged, under the spring preload, against the two shoulders 82 and 84 which delimit the peripheral groove 86. The washers 88 are slotted so as to be mounted in the groove 86 of the sleeve 80. The washers 88 have an outer diameter greater than that of the shoulders 82 and 84.

  The outlet slide 20 is also in the form of a sleeve 90 which is mounted coaxially with the sleeve 80. The sleeve 90 has a peripheral radially inner shoulder 92 at one end whereas the output shaft T1 of the actuator Al is a tubular element which engages inside the sleeve 90 on the side opposite to the shoulder 92.

  The assembly is carried out so that the shoulder 92 of the sleeve 90 and the inner end of the outlet rod T1 respectively come into contact with the two washers 88.

  When the sleeve D moves to the left, the shoulder 82 of the sleeve 80 of the input slider 18 drives the output member T1 of the actuator A1 via the spring R which bears on said output member. T1, or compresses the spring R without driving the output rod T1 when it provides a resistant force that opposes its movement. If the sleeve D moves to the right, it is the shoulder 84 of the sleeve 80 which drives the outlet slide 20 via the spring which bears on the shoulder 92 of the sleeve 90.

  As a variant of this third embodiment, the drive shaft of the actuator and the threaded shaft of the motion transformation system could be axially aligned with each other by taking up generally the structure of the first, second or third embodiment.

  A fourth embodiment of a control assembly E with a single actuator A or integrated actuator will be described hereinafter with reference to FIGS. 15 and 16, which will make it possible to directly control the movement of the players of the gearbox.

  The output rod T of the actuator A constitutes a single output shaft that is both movable in translation and in rotation to control the gearbox butts, knowing that the rotary movement will be used to perform selecting the rank of the report to engage, while the translational movement will be used to engage the selected report.

  In general, the translational movement of the output shaft T of the actuator A is ensured in a similar manner to the actuators described above, namely: an electric motor M, a gearbox 12 with straight teeth, a motion transformation system ST with a ball bushing which is mounted coaxially around the threaded shaft 10 rotated by the motor M, an input slider 18 and an output slider 20 with interposition of a spring, the output shaft T of the actuator A being mounted axially integral in a housing L of the output slide 20 but being free to rotate.

  The rotational movement of the output shaft T of the actuator A is obtained from: - a second electric motor M ', and - a gear 12' with an epicyclic gear train, for example rotatably coupled to the shaft of the second electric motor M ', while the output shaft 100 of the gear 12' is mounted fixed in translation but rotatably connected to the output shaft T of the actuator A which is in its axial extension.

  This results in the presence of a coupling device 101 between the output shaft 100 of the gearbox 12 and the output shaft T of the actuator A, which allows telescopic movement between these two shafts. Such a coupling can be achieved by means of splines, or a pin penetrating into an oblong shaped light, for example.

  Advantageously, in order to be able to perform a preselection of the selection range of the chosen ratio, a resilient rotary link is introduced with curved or preloaded straight springs, mounted in a cassette for example, between the movable ring gear 102 of the epicyclic gear train of the gearbox 12 'and its drive shaft. exit 100.

  A passage finger 104 is secured to the output shaft T of the actuator A and is intended to cooperate with one of a set of gearbox sticks 106 which are arranged in the example described. , radially. Alternatively, the brackets 106 could be arranged in parallel being superimposed on top of each other, as in the case of a traditional gearbox, knowing then that they must be arranged so as to always have a portion that can be actuated by the passage finger 104 in its rotational movement.

  Such an actuator A eliminates all the internal control that is located between the outer shafts and the passage finger of the butts in the gearbox, including the selection of return springs which are responsible for keeping this finger in the rank of 3rd and 4th reports. However, these springs also allow in a traditional gearbox to prevent noise from the shocks of the control finger against the sticks, when the assembly is particularly subject to the vibratory modes of the transmission.

  Also, to ensure this function in the actuator according to the invention, it is advantageous to report a blasting 110 on the reduction gear 12 'epicyclic train, this blasting 110 ensuring a holding function in angular position, with indexing, corresponding to the ranks of possible ratios of the gearbox. The blasting 110 can thus prevent the passage finger 104 from clashing with the other sticks or deflecting the desired position.

  Alternatively, the blasting 110 could be mounted in the gearbox so as to overcome manufacturing tolerances and mounting positioning, and also reduce the size of the actuator.

  A locking device of the sticks 106 is also to be provided, this device can be mounted in the gearbox control fork, for example, and be constituted by a locking said "ball and man", disk, ...

  Finally, it is desirable to have a torque limiter in each transmission kinematic transmission chain (passage and gear selection) and this, in order to optimally optimize the dimensioning of the various components of the actuator and ensure their non-destruction during extreme operating conditions.

Claims (12)

  1. Control unit for a motor vehicle automated gearbox, comprising at least one actuator (A, A1, A2) for passing and / or selecting the gear ratios, and a power electronics (EP) for driving the actuator (A, Al, A2), said actuator comprising in particular an electric motor (M, M1, M2) and a system (ST, ST1, ST2) for transforming the rotational movement of the output shaft of the motor into a translation movement which is communicated by a motion transmission device (DT, DT1, DT2) to an output element (T1, T2) of the actuator for controlling the gearbox, the transformation system (ST1, ST2 ) comprising a threaded shaft (10) coupled to the motor output shaft (Ml, M2), and at least one translatable member (15) which is in contact with the threaded shaft (10) and is connected to the motion transmission device (DT, DT1, DT2) which includes. an elastic connection (R), the motion transmission device (DT, DT1, DT2) consisting of an input member (18) and an output member (20) guided in translation, where the element inlet (18) is secured to the movable member (15) of the motion transformation system (ST, ST1, ST2), wherein the output member (20) is integral with the output member (T1, T2) of the actuator, and wherein the elastic connection is formed of a spring (R) mounted in axial support between the input and output elements (18, 20), characterized in that the output element ( T1, T2) of the actuator (A, Al, A2) is constituted by a rod fixed by a rotatable connection (24) to the output slide (20).   2. Control assembly according to claim 1, characterized in that the spring (R) is supported at each of its ends on an axial portion of one of the input and output elements (18, 20) and on parts symmetrical with respect to the axis of the spring (R) of the other of the input and output elements (18, 20).   Control assembly according to claim 1 or 2, characterized in that the threading of the threaded shaft (10) of the motion transformation system (ST, ST1, ST2) is at a constant pitch, and that the movable member (15) in contact with the threaded shaft (10) is a ball screw, a ball bushing or the like.   4. Control assembly according to claim 1 or 2, characterized in that the thread of the threaded shaft (10) of the system (ST, ST1, ST2) of motion transformation is variable pitch.   5. Control assembly according to claim 4, characterized in that the threading of the threaded shaft (10) of the system (ST1, ST2) of motion transformation has a wider pitch in its central part than towards its two ends.   6. Control assembly according to claim 5, characterized in that the thread is removed at each end of the threaded shaft (10).   7. Control assembly according to any one of claims 4 to 6, characterized in that the movable member (15) in contact with the threaded shaft (10) is: a rolling pin (P), a rolling roller or similar.   8. Control assembly according to claim 7, characterized in that the movable member (15) in contact with the threaded shaft (10) is a rolling pin (P) having a frustoconical shape, roll or ogive.   9. Control assembly according to claim 8, characterized in that the rolling pin (P) is fitted in the inner race (20a) or in the outer race (20b) of a bearing (20).   10. Control assembly according to claim 8, characterized in that the rolling pin (P) is formed by the inner race (20a) or the outer race (20b) of a bearing (20).   11. Control assembly according to one of claims 1 to 10, characterized in that the input element (18) consists of two metal sheets (45) stamped, parallel and spaced from each other by small columns (47).   12. Control unit according to the. claim 11, characterized in that an interior space delimited between the two sheets (45) allows the guiding of the input and output elements (18,20) along a fixed partition (48) which extends in parallel to the threaded shaft (10).