FR3024197A1 - MANUAL GEARBOX CONTROL OF A MOTOR VEHICLE - Google Patents

Abstract

This gear ratio selection device for a motor vehicle comprises a selection control key (4) comprising a cylindrical body (10). The selection control key (4) is rotatably mounted about the axis (6) of the cylindrical body (10) relative to the clutch housing (2) of the gearbox. The outer surface of the cylindrical body (10) comprises a tooth (40), the selection device further comprising a hard point actuator (28) arranged to exert an elastic force directed radially with respect to the cylindrical body (10) and against the tooth (40).

Description

The present invention relates to the field of manual gearboxes of motor vehicles with parallel shafts and gears. More specifically, it relates to a gear ratio selection device for such a gearbox. A manually controlled gearbox by definition includes an external command, usually a gear lever, connected via a mechanical link to a gear ratio selection control key. The selection control key is capable of controlling the passage actuators to engage a gear ratio. In order for the gear lever to transcribe amplitude movements suitable for the driver, the mechanical connection between the lever and the selection control key has gear ratios. A well-known disadvantage of this system is the need for precise factory setting of the relative positions of the internal control and the external control. In fact, the gear ratios accentuate the dispersions of the internal control of the gearbox. Such dispersions can be at the origin of refusal of gearshifts.

In addition, the more selection gate and passage of the external control of the gearbox has speed lines, the more this disadvantage is handicapping. Thus the adjustment of the relative positions becomes particularly delicate and expensive when the external control has at the lever four lines of speeds. This is the case, for example, for vehicles with five or six forward gears, spread over three lines, and a reverse gear on the fourth line. EP 1 111 276 and FR 2 927 684 disclose internal manual gearbox control devices 3024197 2 comprising a selection control key. The latter has a retractable stop to prohibit access to a speed line, in this case that of the reverse. The function of such a device is to prohibit the selection of a speed line, in this case that of reverse gear, when the driver obviously wants to select a speed line of a forward gear. This results in a lower risk of refusal to shift gears. However, such a device has a significant additional cost compared to a mechanical connection without retractable stop. The operation at the time of assembly is complex, which can give rise to operating problems if the latter is poorly carried out. In view of the foregoing, the object of the invention is to provide a speed ratio selection device having means for prohibiting the selection of a speed line when this is not desired by the speed ratio. 'user. According to a first aspect of the invention, a gear ratio selection device for a motor vehicle, comprising a selection control key comprising a cylindrical body, the selection control key being rotatably mounted about the body axis. cylindrical relative to the clutch housing of the gearbox. The outer surface of the cylindrical body comprises a tooth. The device further comprises a hard point actuator arranged to exert an elastic force directed radially with respect to the cylindrical body and against the tooth.

The hard point actuator can thus generate a torque at the origin of a force felt by the driver. A speed line is then locked by the hard point actuator, the driver being obliged to provide additional effort if he wishes to pass a report of this speed line.

Advantageously, the internal control key is free to pivot between a first stop and a second stop and comprises an O-ring arranged to be potentially in contact with the first stop and the second stop.

According to one embodiment, the selection control key comprises an arm integral with the cylindrical body, the device comprising a return pin integral with the clutch housing and an elastic return means of the arm with respect to the return pin.

The elastic return means may be a torsion spring disposed between the return pin and the arm of the internal control key. Advantageously, the tooth has a substantially cylindrical outer surface.

Such a tooth and such a hard point actuator make it possible, when the latter is compressed, to exert a point force at the beginning of the movement between the two speed lines. Advantageously, the tooth comprises on one of its flanks a sloped surface having an angle of between 5 ° and 10 ° with the radial direction. According to one embodiment, the hard point actuator comprises a cartridge inside which there is a spring and a pressure element. In such an embodiment, the pressure member may be a pressure finger with a hemispherically shaped end. For example, the pressure element may be a ball. Still in such an embodiment, the spring may be disposed between the cartridge and the pressure element. Advantageously, the pressure element is able to contact the tooth of the cylindrical body of the selection control key. According to one embodiment, the selection control key may be in a first angular position corresponding to a forward gears ratio, in which the pressure element is in contact with one of the flanks of the tooth. a second angular position corresponding to the reverse ratio in which the pressure element is in contact with the outer surface of the tooth.

In this example, the additional force generated by the hard point actuator and felt by the driver is exerted when the driver engages the reverse gear. Other objects, features and advantages of the invention will become apparent on reading the following description, given solely by way of nonlimiting example, and with reference to the appended drawings in which: FIG. 1 is an isometric view of the speed ratio selection device of a manual transmission for an automobile vehicle; FIG. 2 is an axial view of the selection control key of the device of FIG. 1 directed along a first speed line; FIG. 3 is an axial view of the selection control key of the device of FIG. 1 directed along a second speed line, FIG. 4 is an axial view of the selection control key of the device of FIG. directed at a third speed line; FIG. 5 is an axial view of the selection control key of the device of FIG. 1 directed along a fourth speed line, FIG. axial view of the tooth of the control key of FIGS. 1 to 5; FIG. 7 is a graph illustrating the return force felt by the driver as a function of the position of the lever when it is set in motion in the direction of the first gear line to the fourth, and - Figure 8 is the same graph as that of Figure 6, the lever being moved in the opposite direction. Figure 1 is a sectional view of a clutch housing 2 manually controlled gearbox. The gearbox comprises a gear ratio selection device provided with an external control lever shifter not shown in the figures. The gear lever 3024197 is connected via a mechanical connection not shown to a gear ratio selection control key 4. The control key 4 is rotatably mounted about an axis 6 with respect to the clutch housing 2.

The operation of a selection control key is well known in the state of the art and is for example described in the document FR 2 927 684. The control key 4 ensures the movement of the passage actuators (not shown in FIG. FIGS.) from a passage control finger 8. The passage control finger 8 moves in rotation about the axis 6 during the selection of a speed line and in translation in the direction of the axis 6 to pass a speed on the selected speed line. The speed lines are shown in Figures 2 to 5 and will be detailed later.

The selection control key 4 comprises a cylindrical body 10 about the axis 6. The passage control finger 8 is located on the surface of the cylindrical body 10. The cylindrical body 10 is integral with an arm 12. The arm 12 is connected to the gear lever via the aforementioned mechanical link. The movement of the gear lever (not shown) causes the arm 12 to move, then the selection control key 4 to rotate around the axis 6. The clutch housing 2 comprises a first stop 14 and a second stop 16, both located at the same distance from a point of the axis 6. The arm 12 of the key 4 comprises an O-ring 18 disposed at the same distance from the same point of the axis 6. In this way, the stops 14 and 16 and the O-ring 18 are located on the same circle whose center is a point of the axis 6 of rotation of the selection control key 4. Thus, when the selection control key 4 pivots around the axis 6, the O-ring 18 is able to come into contact with the first stop 14 and the second stop 16. This arrangement allows the selection control key 4 to pivot according to an angular movement limited by the two positions 14 and 16, the O-ring 18 for absorbing ber shocks.

The speed ratio selection device further comprises a pin 20 integral with the clutch housing 2. The pin 20 is disposed facing the arm 12 of the selection control key. The selection device also comprises a torsion spring 22, inserted in a groove 24 of the cylindrical body 10. The arm 12 of the control key 4 comprises a lug 26 near its end. The torsion spring 22 comprises a high leg 22a and a low leg 22b. When the selection control key 4 is in the position as illustrated in FIG. 1, the high tab 22a is in contact with the top right face (with respect to FIG. 1) of the lug 26, the lower leg 22b being in contact with the bottom right side (with respect to FIG. 1) of the lug 26. The lugs 22a and 22b also pass on one side and the other of the pin 20. This torsion spring 22 exerts an elastic return force on the arm 12 relative to the pin 15 20, so as to return the selection control key 4 to a return position when the latter away from it. The return position corresponds to the position of the key 4 as shown in FIG. 1, in which the arm 12 is opposite the peg 20. FIGS. 2 to 5 show the same sectional view of FIG. gear ratio selection device of Fig. 1, with the four speed lines drawn in dashed lines. In each figure, the selection control key 4 is positioned in the position corresponding to a respective speed line. In this example, the gearbox provides six forward gears and one reverse gears. FIG. 2 shows the selection control key 4 positioned in the direction of a first speed line I. The first speed line I corresponds to the fifth and sixth gear ratios. With respect to the equilibrium position shown in FIG. 1, the control key 4 has been rotated by an angle α in the clockwise direction (with respect to FIG. 2). In this vehicle, the selection control key 4 is positioned in the direction of the first speed line I when the shift lever is shifted to the right with respect to its neutral position.

FIG. 3 shows the selection control key 4 positioned in the direction of a second speed line II. The second gear line II corresponds to the third and fourth gear ratios. The position of the second speed line II corresponds to the equilibrium position of the selection control key 4. FIG. 4 shows the selection control key 4 positioned in the direction of a third line of speeds III. The third gear line III corresponds to the first and second gear ratios. With respect to the equilibrium position shown in FIGS. 1 and 3, the control key 4 has been rotated by an angle α counterclockwise (with respect to FIG. 4). In this vehicle, the selection control key 4 is positioned in the direction of the third gear line III when the gear lever is shifted to a left intermediate position with respect to its neutral position. FIG. 5 shows the selection control key 4 positioned in the direction of a fourth speed line IV. The fourth speed line IV corresponds to the reverse gear ratio. With respect to the equilibrium position shown in FIG. 1, the control key 4 has been rotated by an angle 2 * a counterclockwise (with respect to FIG. 5). In this vehicle, the selection control key 4 is positioned in the direction of the fourth speed line IV when the shift lever is shifted to a far left position relative to its neutral position. The torsion spring 22 exerts a different return force according to the different positions of the selection control key 4. When the control key 4 is directed along the first speed line I, only the lower leg 22b is in contact with the lug 26, so that the return force is directed in the counterclockwise direction (with respect to Figures 2 to 5). When the control key 4 is directed along the second speed line II, the two lugs 22a and 22b are in contact with the lug 26, so that there is no return force.

When the control key 4 is directed along the third line III or the fourth line IV, only the upper leg 22a is in contact with the pin, so that there is a return force directed in the clockwise direction ( compared to Figures 2 to 5). Ultimately, the torsion spring 22 generates an elastic return of the control key 4 to its equilibrium position, the second speed line II. Such an elastic return means is important because it provides the driver with information concerning the position of his shifter. This has many advantages, for example, to avoid him leaving the road eyes to watch the position of the shifter while the vehicle is moving. Thus, for example, when the vehicle is en-route at fifth speed and the driver wishes to downshift in fourth gear, he selects the corresponding gear line (the second gear line II) operating to felt, as he feels a return force to the left, to the right or does not feel a return effort. However, the direction of the return force is the same when the shifter is facing the reverse line (IV) or facing the line of first and second gear ratios (III), the only difference being that the value of this return force is greater compared to the reverse line (IV). Such a difference, however, is too small to be frankly felt by the driver. This explains that the elastic return means is less effective for gearboxes providing a reverse line separate from the forward lines, as is the case in the embodiment shown. To overcome this drawback, the selection device comprises a hard point actuator 28 shown in section in FIGS. 1 to 5. The hard point actuator 28 is embedded in the clutch housing 2 so as to exert an elastic force directed against the arm 12 of the control key 4.

The function of the hard point actuator 28 is to generate an additional return force in addition to the return force to improve the feeling of the driver. The hard point actuator 28 comprises a cartridge 30. The cartridge 30 is in the form of a screw comprising a head 28a and a rod 28b clamped in a threaded bore 32 formed in the clutch housing 2. In this way, the body 30 is integral with the clutch housing 2. Inside the body 30 are mounted a spring 34 and a pressure finger 36 comprising a hemispherical end 38.

The spring 34 is mounted between the cartridge 30 and the pressure finger 36, abutting the end of the finger 36 opposite the hemispherical end 38. The cylindrical body 10 further comprises a tooth 40, shown in perspective on the FIG. 1 and in axial view in FIGS. 2 to 6. The position of the body 30 is such that the end of the piston 36 is capable of coming into contact with the tooth 40 of the selection control key 4. As can be seen in FIG. As can be seen in FIG. 6, the tooth comprises a flank 42 and an outer face 44. The flank 42 extends substantially in a plane forming an angle p with the radial direction relative to the cylindrical body 10. In this embodiment the outer face 44 has substantially the shape of a portion of a cylinder about the axis 6. In other words, for any point X of the outer surface 44, the plane tangent to said outer surface 44 at the of point X makes an angle of less than 1 ° with the ortho-rad plane ial with respect to the axis 6 containing the point X. Thus, according to the angular position of the selection control key 4, the pressure finger 36 may or may not be in contact with the tooth 40. In the case where it is in contact, it may be in contact with the flank 42 or with the outer face 44. When the pressure finger 36 is in contact with the flank 42, an additional return force applied to the selection control key 4 appears. Next, FIGS. 2 to 5 will be used to detail the return force 3024197 felt by the driver as a function of the angular position of the selection control key 4. It is possible, without departing from the scope of the invention, consider an embodiment wherein the pressure member, instead of the piston 36, 5 is a ball. The ball may then be decomposed into two hemispheres, one held in contact with the spring 34, the other in contact with the key 4 or its tooth 40. FIGS. 2 and 3 respectively illustrate the directed control key 4 according to the first and second speed lines I and II. In this configuration, the pressure finger 36 is not in contact with the tooth 40 but directly with the peripheral surface of the cylindrical body 10. FIG. 4 illustrates the selection control key 4 directed along the third speed line III. In this configuration, the actuating member 36 is at the limit of contact with the flank 42 of the tooth 40. The spring 34 is thus relaxed in this configuration. FIG. 5 illustrates the selection control key 4 directed along the fourth speed line IV. In this configuration, the actuating element 36 is in contact with the outer face 44 of the tooth 40. The spring 34 is therefore stretched. FIGS. 7 and 8 show a graph illustrating the value of the force c felt by the driver as a function of the angular position of the selection control key 4 between the speed lines I and IV.

The value of the force c when the key 4 is directed along the second speed line (II) is zero, as indicated in FIG. 7. When the control key 4 is directed along the first speed line I or according to the third speed line III, the value of the force is the same, equal to a value £ 1 depending only on the stiffness of the torsion spring 22. When the control key 4 is directed according to the fourth speed line IV , the value of the force c is equal to a value 2 2 greater than ci, and also depends on the stiffness of the torsion spring 22.

The graph of FIG. 7 illustrates the evolution of the force e when the selection control key 4 pivots counterclockwise with respect to FIGS. 2 to 5, that is to say from the first line of speed I at the fourth speed line IV.

From the first speed line I to the second speed line II, the change in the value of the force e is decreasing and linear between the values £ 1 and 0. In a symmetrical manner, the value of the force progressively increases linearly between the values 0 and £ 1 when the control key 4 rotates from the second speed line II to the third speed line III. When the control key 4 is directed along the third speed line III, the pressure finger 36 is at the limit of the contact with the flank 42 of the tooth 40. As soon as the control key 4 leaves the angular position of the third line III to the fourth line IV, the surface inclined at the angle p of the flank 42 of the tooth 40 forces the compression of the spring 34. This generates a force on the tooth 40, which results in an additional return torque in the clockwise direction (with respect to FIGS. 2 to 5) which is added to the basic restoring torque 20 due to the torsion spring 22. The force ρ therefore increases immediately after the control key 4 has left the position of third line III up to a value £ 3. The value £ 3 and the speed of this growth are all the higher as the value of the angle p is small. Preferably, the value £ 3 is preponderant in front of the values £ 1 and £ 2, so that the restoring moment is strongly accentuated when the key 4 leaves the third line III towards the fourth line IV. When the value £ 3 is reached, the force déc decreases to a value 4 4 between the values 1 1 and 2 2 defined above. The speed of this decrease is of the same order of magnitude as that of the growth of the value £ 1 at the value £ 3. Then, the value of the force e increases slightly to reach the value £ 2 at the end of rotation. The graph of FIG. 8 illustrates the evolution of the force e when the selection control key 4 pivots clockwise 3024197 12 with respect to FIGS. 2 to 5, that is to say from the fourth line of FIG. speed IV at the first speed line I. From the fourth speed line IV to the third speed line III, the evolution of the value of the effort £ is in two stages.

In a first step, the force déc decreases linearly between the values £ 2 and 4 4 defined above. When the force e is equal to 4, the pressure finger 36 is in contact with the ridge between the outer face 44 and the flank 42 of the tooth 40. Immediately after this angular position, the force E decreases discontinuous between positions £ 4 and £ 1. From the third speed line III to the second speed line, the evolution of the value of the force e is decreasing and linear between the values £ 1 and 0. Then, symmetrically, the value of the effort £ evolves in 15 linearly increasing between the values 0 and £ 1 when the control key 4 pivots from the second speed line II to the first velocity line I. The rates of variation are, in absolute value, of the same order of magnitude. magnitude when the effort £ evolves between the respective values £ 2 and £ 4, 20 ci and 0, 0 and ci. By this graph, it is clear that the driver feels a greater return force in the specific case where the lever has just crossed the third gear line III towards the fourth speed line IV. This results in a better perception of the position of the gear ratio selection control for the driver. The driver is obliged to provide extra effort if he wishes to pass the reverse gear. We can then consider that the reverse line is locked. The value £ 3 is predominant in front of the values £ 1, £ 2 and £ 4. In this way, the effort to cross the third gear line is felt as a high and punctual effort. On the other hand, the effort is felt when the driver moves the shifter from the third line III to the fourth line IV, and not in the opposite direction.

Thus, the speed ratio selection device presented in this embodiment of the invention makes it possible to generate a point and a single hard point in order to block the reverse gear ratio of the vehicle gearbox.

This results in a better feeling for the driver and a lower probability of refusal of gearshift, which can furthermore allow a longer life of the vehicle gearbox. It is also possible to modify the maximum value and the rate of variation of the force felt by the driver, by acting on the angle p of the sidewall 42 with respect to the radial direction. Moreover, in this embodiment, once the hard point is crossed, the effort felt by the driver changes little. This is due in particular to the cylindricity of the outer surface 44 of the tooth. However, it is conceivable, without departing from the invention, an outer surface away from the axis 6 as one moves away from the angular position of the third speed line III. In such a variant, the effort felt can increase as one approaches the reverse.

Claims (12)

REVENDICATIONS1. Gear ratio selection device for a motor vehicle, comprising a selection control key (4) having a cylindrical body (10), the selection control key (4) being rotatably mounted about the axis (6) of the cylindrical body (10) with respect to the clutch housing (2) of the gearbox, characterized in that the outer surface of the cylindrical body (10) comprises a tooth (40), the selection device further comprising an actuator hard point (28) arranged to exert an elastic force directed radially with respect to the cylindrical body (10) and against the tooth (40). 2. Device according to claim 1, characterized in that the selection control key (4) is free to pivot between a first stop (14) and a second stop (16) and comprises an O-ring (18) disposed so to potentially be in contact with the first stop (14) and the second stop (16). 3. Device according to one of claims 1 and 2, characterized in that the selection control key (4) comprises an arm (12) integral with the cylindrical body (10), the device comprising a return pin (20). secured to the clutch housing (2) and an elastic return means of the arm (12) relative to the return pin (20). 4. Device according to one of the preceding claims, characterized in that the elastic return means is a torsion spring (22) disposed between the return pin (20) and the arm (12) of the selection control key (4). 5. Device according to any one of the preceding claims, characterized in that the tooth (40) has a substantially cylindrical outer surface (44). 6. Device according to any one of the preceding claims, characterized in that the tooth (40) comprises on one of its flanks (42) a sloping surface having an angle 03) of between 5 ° and 10 ° with the radial direction. 3024197 15 7. Device according to any one of the preceding claims, characterized in that the hard point actuator (28) comprises a cartridge (30) inside which there is a spring (34) and a pressure element. 5 8. Device according to claim 7, characterized in that the pressure element is a pressure finger (36) with an end (38) of hemispherical shape. 9. Device according to claim 7, characterized in that the pressure element is a ball. 10 10. Device according to any one of claims 7 to 9, characterized in that the spring (34) is disposed between the cartridge (30) and the pressure element. Device according to one of claims 7 to 10, characterized in that the pressure element is capable of contacting the tooth (40) of the cylindrical body (10) of the selection control key. (2). Device according to claim 11, characterized in that the selection control key (4) can be in a first angular position (III) corresponding to a forward gears ratio, in which the pressure element (36) is in contact with one of the flanks (42) of the tooth (40), a second angular position (IV) corresponding to the reverse gear ratio in which the pressure element (36) is in contact with the outer surface (44) of the tooth (40).