FR2764358A1 - DEVICE FOR OPERATING A SWITCHING SHAFT OF A GEARBOX - Google Patents

Abstract

The invention relates to a device for actuating a switching shaft of a gearbox, movable by pivoting about an axis and by translation along this axis. The device comprises a device for operating in translation 20, which is connected to the switching shaft 2 via a group of connecting elements 24, 28, 44 to produce a translation of the switching shaft, and a pivoting operating member 18, which is connected to the switching shaft 2 via a group of connecting elements 22, 26, 38, 32 to produce a pivoting of the switching shaft, these groups of connecting elements each comprising a hinge rod 44, 38 one end of which is hingedly connected to the associated operating member 20, 18 and the other end of which is hingedly connected to the switching shaft 2.

Description

The present invention relates to a device for actuating a shaft of

  switching of a gearbox, movable by pivoting about an axis and by translation along this axis, device comprising a member for operating in translation, which is connected to the switching shaft by means of a group of connecting elements to produce a translation of the switching shaft, and a pivoting actuator, which is connected to the switching shaft via a group of connecting elements to produce a pivoting of the switching shaft, this group of connecting elements being provided with articulations and requesting a pivoting lever, rigidly connected to the switching shaft, the translation and pivoting movements being uncoupled one of the other at

less to a large extent.

  Gearbox automation has become more and more important in recent times. On the one hand, such automated gearboxes are less expensive than conventional automatic transmissions, which operate for example with planetary trains or which are arranged in the form of transmissions comprising a transmission member passing over conical pulleys and ensuring variation transmission report. On the other hand, automated transmissions operate with better efficiency than conventional automatic transmissions so that the increase in comfort is not offset by an increase in fuel consumption. For the actuation of gearboxes, a switching shaft is normally provided, which is pivotally mounted and with the possibility of translation along its bearing axis. Such a conventional switching shaft is shown in FIG. 6. This switching shaft 2 comprises a switching finger 4, forming a single piece with it and engaging in the recesses of switching forks 6, arranged in the U-shaped assemblies which can be moved alternately and in a known manner respectively linearly along switching paths 8 and which thus produce speed switching. The switching shaft 2 can be moved axially in the direction of the double arrow W to select a switching channel. To produce a translation of a corresponding switching fork 6 or else to produce a gear or ratio switching, the switching shaft 2 can be moved by pivoting or by rotation in the direction of the double arrow S. It is also known realizations in which the switching shaft is moved in rotation for a selection of switching channels and in translation in an axial direction or in a longitudinal direction for a switching

of speeds.

  During an automation of such a gearbox actuation device, an operating member is provided to produce the pivoting movement and the translational movement of the switching shaft, which is connected to the switching shaft via an associated group of connecting elements. In an actuation device known from United States patent US 4,856,360, the two operating members comprise elements

  actuators linearly displaceable in translation.

  The actuating element producing a translational movement of the switching shaft is connected to this shaft by means of a component, which is rigidly coupled to the switching shaft in its axial direction but which nevertheless allows a relative rotation of this switching shaft. The actuating element producing the pivoting movement of the switching shaft is engaged in a pivoting lever rigidly connected to the switching shaft so that, when actuated, it produces a pivoting movement of the switching shaft whereas, however, during an axial translation of the switching shaft, a corresponding relative movement may

  occur between the actuator and the lever.

  A particular arrangement of such switching shaft actuating devices, and other corresponding devices consists in that the coupling provided between the switching shaft and the actuating element, which is rigid in one direction but which is however free in a perpendicular direction, allows only a limited actuation precision to be obtained. On the other hand, high friction occurs, which requires on the one hand powerful operating members and which can on the other hand cause deformations in the groups of elements

link.

  The invention therefore aims to create a device for actuating a switching shaft of a gearbox, which can pivot around an axis and which can be displaced in translation along this axis, this device being of simple construction, operating with precision and giving rise to only small losses. This problem is solved in accordance with the invention in that at least one of the groups of connecting elements comprises an articulation rod, one end of which is hingedly connected to the associated operating member and the other end of which is articulated

to the switching shaft.

  According to another characteristic of the i.ve..i: on, the problem is also solved by the fact that the groups of connecting elements each comprise a hinge rod, one end of which is hingedly connected to the 'associated operating member and the other end of which is hingedly connected to the switching shaft. In this regard, it is advantageous in an exemplary embodiment, that the articulation rod contained in the group of connecting elements for the articulation of the switching shaft acts substantially parallel to the axis

of the switching shaft.

  The device according to the invention in which the group of connecting elements ensuring the switching, the group of connecting elements ensuring the selection, or else the two connecting groups, comprise an articulation rod provided with two articulations and which establishes the coupling between the operating member and the switching shaft, is generally arranged as an articulated space system comprising at least four joints. Consequently, it is not necessary to involve linear translations, and affected by friction, between different elements of the group of connecting elements or else between elements of the group of connecting elements and the switching shaft. This completely avoids difficulties such as those manifested for example during a shift of conical teeth for the transmission of a torque, and also when groups of rolling elements are provided to reduce friction. The device according to the invention can be produced inexpensively and it works in an extremely safe manner and with

losses.

  According to other particularities of the invention: the member for this translational maneuver and the pivoting maneuvering member each combine an electric motor which is driven by means of a transmission mechanism, a component which is hingedly connected to the associated articulation rod; - the component driven by the operating member and connected in an articulated manner to the articulation rod is rigidly connected to the tangent wheel of a worm gear transmission and tangent wheel; the articulations of the articulation rods are ball joints; the lengths of the articulation rods are dimensioned such that a translation or a pivoting of the switching shaft produces only small angular modifications of the position of the articulation rod associated with the operating member in

  pivoting or to the operating member in translation.

  In this case, a complete uncoupling is obtained in particular between the switching movement and the movement.

  for selecting the switching shaft.

  According to yet another advantageous characteristic of the device according to the invention, at least one of the articulation rods is arranged so as to undergo elastic deformation in its two longitudinal directions when a predetermined force is exceeded. Thus, thanks to the possibility of elastic deformation of one of the articulation rods, there can be no excessive force inside the group of connecting elements or else the actuating devices of the gearbox are not excessively stressed when a limit position or a stop is reached. In addition, such an elastically deformable arrangement of the articulation rod is advantageous in specific applications where a force must be measured, since this force can be determined directly by measuring the elastic deformation of

the articulation rod.

  According to still other characteristics of the device according to the invention: - The articulated rod of elastic structure

  includes a linkage operating in traction / thrust.

  - The linkage operating in traction / thrust comprises a retaining component provided with an oblong hole, in which is preloaded a helical spring, which additionally penetrates into an oblong hole, aligned with the oblong hole of the retaining component and which is formed in a component associated with the articulation rod and movable in translation relative to

to the retaining component.

  - The possibility of translation of the component associated with the articulation rod relative to the retaining component is limited by at least one abutment stud, which engages in an abutment hole, provided with a corresponding surge, of the associated component to the articulation rod. The invention is advantageously applicable in all cases where conventional gearboxes comprising a switching axis displaceable by pivoting about an axis and in translation along this axis, must be actuated by means of actuators, that these gearboxes are completely automated or else the gears are obviously switched according to the driver's wishes, this operation however not being able to be carried out directly by means of switching but by means of operating devices. Such actuators can be electric motors, hydraulic motors or other drive devices

motorized.

  Other characteristics and advantages of the invention will be highlighted in the rest of the

  description, given by way of nonlimiting example, in

  reference to the accompanying drawings in which: FIG. 1 is a perspective view in principle of a device according to the invention, FIG. 2 represents a variant of the device of FIG. 1, FIG. 3 is a partial schematic representation showing evidence of a pre-stressed elastic system inside a linkage, FIG. 4 shows a side section view of an elastic system provided in a linkage, FIG. 5 is a sectional view of the arrangement of Figure 4, the section being taken in the plane VV of Figure 4, and Figure 6 shows a switching shaft

corresponding to the prior art.

  According to FIG. 1, the switching shaft 2, guided in axial translation and in pivoting in the

  casing 10 of a gearbox, comes out of this casing 10.

  On the switching shaft 2 is fixed a pivoting lever 12, which comprises at its end a swiveling pin 14. Another swiveling pin 16 is fixed on the switching shaft 2 by means of articulation means , as close as possible to the central axis of the switching shaft or

directly on it.

  For actuation of the switching axis 2, there are provided two operating members, arranged like electric motors 18 and 20 and which are fixed

  directly on the gearbox casing 10.

  Each of the electric motors 18 or 20 has an output shaft 22 or 24, which forms the worm of a worm gear and wheel reduction mechanism

  tangent, the tangent wheel being designated by 26 or 28.

  The tangent wheels 26 and 28 are mounted, like the electric motors, directly on the casing 10 of

the gearbox.

  To each tangent wheel 26 or 28 is connected in a non-rotating manner an eccentric lever 30 or 32, at the end of which is arranged a swiveling pin 34 or 36. The swiveling pins 14 and 34 are connected by means of a rod of articulation 38, which is provided at its ends with spherical caps 40 and 42, which are fitted on the journal pins 34 and 14. In a completely analogous manner, the journal pins 16 and 36 are connected by means an articulation rod 44, which is provided at its ends with spherical caps 46 and 48 which are fitted onto the journal pins 16 and 36. The mode of operation of the device described can be understood immediately. When one of the electric motors 18 or 20 is engaged, the associated tangent wheel 26 or 28 is rotated so that the respective associated articulation rod 38 or 44 is moved and the switching shaft 2 is driven in rotation in the direction of a switching operation or in translation in the direction of a selection operation. As shown in the figure, the articulation rod 38 is advantageously oriented approximately tangentially to a circumferential casing of the switching shaft 2 while the articulation rod 44 is oriented approximately parallel to the switching shaft 2. By judiciously matching the lengths of the articulation rods 38 or 44, it is obtained that the angular position of the articulation rod 38 is modified, during a translation of the switching shaft 2 in the selection direction, only a few degrees, for example from 5 to 30, and the angular position of the articulation rod 44 is modified, during a switching pivoting the switching shaft 2, also only by a few degrees. Thus, the operating position of the switching shaft 2 during its translation in a selection direction remains practically unchanged, and vice versa. It is obvious that the reaction effect between the selection position and a change in the switching position, and vice versa, can also be taken into account by means of software in a control device which controls the electric motors. 18 or 20. Depending on the construction requirements, the entire system can be integrated into the gearbox casing 10 or it can be simply installed later in this casing 10, so that it It is possible to carry out inexpensive retrofitting of conventional gearboxes. Furthermore, it is possible to arrange the two rods at an angle to the axis and to produce the necessary movements of rotation of the shaft by appropriate combinations of the two drive systems. Similarly, in another example of implementation, it is possible to produce a longitudinal movement of the shaft by a

  appropriate combination of the two drive systems.

  The appropriate combination of the two drive systems can be considered by means of

  control software in the control unit.

  The device operates with high operational safety and with little friction and is

  largely insensitive to soiling.

  The embodiment of FIG. 2 is in principle similar to that of FIG. 1. Only the components which are different from those of FIG. 1 have been designated by reference numbers. Thus the articulation rod 50, corresponding to the articulation rod 38 of FIG. 1, is provided with an elastic system 52, prestressed if necessary, and which will be explained from

  in more detail using Figures 3 to 5.

  In a retaining component 54, formed of two punched sheet metal parts located one on the other, there is provided an oblong hole 56, in which a helical spring 58 is received, if necessary with prestressing. Externally relative to the oblong hole 56, there are provided in the retaining component two elongated abutment holes 59 in each of which is engaged an abutment stud 60, which is integral with another punched sheet metal part 61, which is located in above the retaining component 54 and which has an oblong hole 62 corresponding to the oblong hole 56 (FIG. 4). Above the retaining component 54, there is provided another piece of punched sheet metal 64, not shown in FIG. 3 and which is provided with another oblong hole 66 corresponding to the oblong hole 56 and into which the helical spring also enters. 58. Component 64 is securely connected to component 61 or else forms a single and

same room with him.

  The retaining component 54 is provided at one end with an articulation bearing, which fulfills the function of the spherical cap 40 or 42 (FIG. 1). Components 61 and 64 together also carry an articulation bearing which fulfills the function of the second

spherical cap.

  The operation of the device described is as follows: FIG. 4 shows the rest position in which the helical spring 58 bears on the front side against the edges of all the oblong holes 56, 62 and 66; thus all the components are mutually aligned so that the stop pins 60 are located in the middle in the stop holes 59. When traction is exerted on the articulation rod 50 by means of the spherical caps 40 and 42 (figure 1), the component 54 moves, in correspondence to figure 4, to the right with respect to the components 61 and 64, so that the prestressed spring 58 (the prestress defines the force necessary for the start of the relative movement) is compressed and the translation is limited by the entry into abutment of the pins 60 against the walls of the abutment holes 59. In a similar manner, the helical spring 58 is compressed when the articulation rod 50 is subjected to a force of thrust, the reduction in length of the articulation rod 50 being again limited by the entry into abutment of the pins 670

  against the walls of the stop holes 59.

  Thus, in the manner described, a hinge rod 50 is created which can deform to a determined degree as soon as the longitudinal forces acting

  on it exceed a predetermined size.

  The claims filed with the request for

  patent are drafting proposals without detrimental effect for obtaining future patent protection. The Applicant also reserves the right to claim other highlighted characteristics

  so far only in the description and / or

in the drawings.

  Attachments used in

  secondary claims relate to other wagers

  implementation of the subject-matter of the main claim by the characteristics of the corresponding secondary claim, but they should not be considered as a renunciation of obtaining specific independent protection of the characteristics of the

  related secondary claims.

  The objects of these secondary claims

  also constitute particular inventions which are of an independent conception of the objects of

  previous secondary claims.

  The invention is also not limited to

  examples of embodiments given in the description. At

  on the contrary, within the framework of the invention, it is possible to envisage numerous variations and modifications, in particular variants, elements and combinations and / or materials which are inventive, for example by combination or modification of certain particularities, or elements, or operational steps, which have been described in relation

  with those described in the general description, the

  embodiments and claims and which are

  contained in the drawings leading, by a combination of features to a new object, or to new operating steps, or to new sequences of operating steps, provided that this also relates to manufacturing, control and

Implementation.

Claims (10)

  1. Device for actuating a switching shaft of a gearbox, movable by pivoting around an axis and by translation along this axis, device comprising a device for operating in translation, which is connected to the shaft of switching via a group of connecting elements to produce a translation of the switching shaft, and a pivoting actuator, which is connected to the switching shaft via a group connecting elements to produce a pivoting of the switching shaft, this group of connecting elements being provided with articulations and requesting a pivoting lever, rigidly connected to the switching shaft, the movements of translation and pivoting being uncoupled from each other at least to a large extent, device characterized in that at least one of the groups of connecting elements comprises a hinge rod, one end of which is connected in an articulated manner abutment to the associated operating member and the other end of which is hingedly connected to the switching shaft.   2. Device for actuating a switching shaft of a gearbox, movable by pivoting about an axis and by translation along this axis, device comprising a member for operating in translation, which is connected to the shaft of switching via a linkage group to produce a translation of the switching shaft, and a pivoting actuator, which is connected to the switching shaft via a group of elements link to produce a pivoting of the switching shaft, this group of connecting elements being provided with articulations and requesting a pivoting lever, rigidly connected to the switching shaft, the translational and pivoting movements being uncoupled at least to a large extent from each other, device characterized in that the groups of connecting elements each comprise a hinge rod, one end of which is hingedly connected to the gold associated operating shaft and the other end of which is connected   hinged way to the switching shaft.   3. Device according to one of claims 1 or   2, characterized in that the translational operating member and the pivoting operating member each comprise an electric motor which drives, via a transmission mechanism, a component which is hingedly connected to the rod associated joint.   4. Device according to claim 3, characterized in that the component driven by the operating member and connected in an articulated manner to the articulation rod is rigidly connected to the tangent wheel   of a worm gear and tangent wheel transmission.   5. Device according to one of claims 1 to 4,   characterized in that the articulations of the rods   articulation are ball joints.   6. Device according to one of claims 1 to 5,   characterized in that the lengths of the articulation rods are dimensioned in such a way that translation or pivoting of the switching shaft produces only small angular changes in the position of the articulation rod associated with the member operating in pivoting or in the operating member in translation.   7. Device according to one of claims! at 6,   characterized in that at least one of the articulation rods is arranged so as to undergo elastic deformation in its two longitudinal directions when a predetermined force is exceeded. 8. Device according to claim 7, characterized in that the articulated rod of elastic structure comprises a linkage operating in traction / thrust. 9. Device according to claim 8, characterized in that the linkage operating in traction / thrust comprises a retaining component provided with an oblong hole, in which is disposed with preload a helical spring, which additionally penetrates into an oblong hole, aligned with the oblong hole of the retaining component and which is formed in a component associated with the articulated and movable rod   in translation relative to the retaining component.   10. Device according to claim 9, characterized in that the possibility of translation of the component associated with the articulation rod relative to the retaining component is limited by at least one stop pin, which engages in a stop hole , provided with a corresponding premium, of the component associated with the articulation rod.