FR2787542A1 - Gearbox internal control has fork moving with second gear change shaft to engage forward gear but releasing it during engagement of rear gear - Google Patents

Abstract

Internal gearbox control comprises internal control shaft connected to vehicle gear change lever. Shaft carries passage finger (2) engaging two pawls (3,4) fixed respectively to first (6) and second (8) gear change shaft of fork (7) controlling passage from forward gear to reverse gear. Fork moves with second shaft to engage forward gear but releases this during engagement of rear gear.

Description

-I -

  INTERNAL GEARBOX CONTROL

  The present invention relates to the internal control of boxes

mechanical speeds.

  The present invention relates more particularly to an internal gearbox control comprising an internal control axis connected to the gear shift lever of the vehicle, carrying a passing finger cooperating with at least two dogs respectively secured to a first control axis of speeds, and a second fork axis controlling the passage of a forward gear and a gear ratio

1o reverse.

  The movements of the internal control axis are controlled by the user from his gear shift lever, via an external control mechanism according to a control grid, determined in particular by the arrangement of the finger passing and

  doggies inside the box.

  In publication FR-2,511,460, on behalf of the applicant, the engagement of the gear pinions with the secondary shaft of a gearbox, in response to the movements of the latter's internal control shaft, is carried out by means of at least one passage finger integral with this axis. When selecting a speed line, the passing finger engages in a dog clutch, while, to engage a gear on the selected line, this dog clutch moves, via a fork axis and d '' a fork, a walkman allowing the synchronization of a pinion of

speed with the secondary shaft.

  The vehicle speed control grid in this case places reverse gear on the same selection line as the fifth gear (the

  reverse being opposite the fifth).

  -2- The reverse control finger is then engaged in the reverse clutch and the forward control finger is engaged in the fifth clutch. The reverse control finger provides double travel with respect to the forward control finger. When engaging reverse gear, the forward control finger drives the fifth dog to this reverse gear and the fifth axis moves to a sixth notional speed, by the value of the engagement stroke of the reverse finger. The fork of io fifth therefore follows an unnecessary course requiring a certain place in the

gearbox housing.

  A constant concern of manufacturers is to reduce the size of gearboxes. The object of the invention is to reduce the size of a gearbox by eliminating, in this gearbox, the space reserved for the simultaneous movement of the fork of

  fifth when moving the reverse gear.

  To this end, the invention proposes a fifth gear moving with the second gear axis to engage a forward gear, but freeing from it when the gait is engaged.

back.

  Other advantages and characteristics of the invention will be put in

  evidence in the following description, given by way of example, with reference

  in the accompanying drawings o: - Figure I partially shows an internal gearbox control device according to the invention, - Figures 2A, 2B, 2C correspond to a section along A of Figure 1

  illustrating the operation of the device of this figure.

  -3 - Figure 1 shows an internal control mechanism of a gearbox according to the invention. This mechanism comprises an internal control pin 1, connected by its upper end to an external control device (not shown), actuated by the gear shift lever of the vehicle. A passing finger 2 is connected to the internal control axis 1. This passing finger 2 makes it possible to choose one of the gear dogs 1-2, 3-4 or 5-reverse gear. In order not to overload the diagram, we have

  shown only the first-second or third- dog 3

  fourth and fifth gear reverse fifth gear.

  Figure 1 also shows the forks 5 of first and second or third and fourth, connected to an axis 6 of speeds 1-2

  or 3-4. A fifth fork 7 is connected to a fifth shaft 8.

  In known manner, the dog clutch 4 carries a control finger 9 connected to a reverse rocker 10 which allows the translation of a pinion

  intermediate 11 reverse gear.

  Figures 2A, 2B, 2C illustrate the operating principle of the internal control of the gearbox according to the invention. To simplify understanding, only the fifth gear reverse gear 4, the axis 8 corresponding to it, the fork 7 of

  fifth and axis 6, of speeds 1-2 or 3-4, devoid of the dog 3.

  The axes 8 and 6 have cutouts 16 and 17, respectively corresponding to a neutral position, a position when a first line speed is engaged and a position when the second line speed is selected. The cutouts of each axis cooperate with a billing system, known per se. This system consists of a ball 18, housed with a spring 19, in a cylindrical lumen produced in

  a casing 20. It stops axes 8 and 6 in translation.

  -4- As shown in these Figures 2A, 2B, 2C, the fork 7 of the fifth is mounted on a hub 71, fitted on the axis 8 of the fifth. The axis 8 has a notch 12, delimited by inclined sides

  12a and 12b, on the periphery of axis 8, on the side of axis 6 of first-

  second or fourth-third. A second notch 13 is formed at the periphery of the axis 6, on the side of the axis 8. This notch is delimited by inclined faces 13a and 13b and has a length substantially equal to that of the notch 12, in

  the nonlimiting example of embodiment illustrated by the figures.

  A cylindrical lumen 14, the axis of which is substantially perpendicular to the axis 8, passes through the hub 71 of the fork 7,

  only on the side of the space between axis 8 and axis 6.

  A stop element, such as a tenon 15, of substantially cylindrical shape, is inserted, with transverse mobility, into the lumen 14. This element, oriented perpendicular to the axis 8, protrudes on either side of the lumen 14. Its two ends 15a, towards the axis 8, and 15b, towards the axis 6, are advantageously of frustoconical shape. The frustoconical end 15a has a diameter substantially equal to the length of the notch 12 and the frustoconical end 15b has a diameter substantially equal to the

length of the notch 13.

  The pin 15 can translate, along its axis, in the lumen 14, towards one of the two axes 6 or 8. The spacing of these two axes is less than the total length of this pin 15 to prevent

  the latter to escape simultaneously from the two notches 12 and 13.

  The functioning of the internal control of the gearbox

  according to the invention will now be explained.

  FIG. 2A represents the position of the fork 7 when the gearbox is in neutral. The billing system blocks the axis 8 in - 5translation, by means of the ball 18 and the cutout of neutral point in said axis 8. The tenon 15 is lowered in the lumen 14, in the direction of axis 8 , to be received by its end 15a, in the notch 12 of said axis. In this way, the fifth fork 7 is made integral with the axis 8, by means of the pin 15. The pin 15 is held in the notch 12 of the axis 8, by means of the generator

of axis 6.

  Figure 2B shows the position of the fork 7 when the fifth is engaged. To do this, the user acts on the external control o0 of the gearbox which transmits the selected speed to the passing finger 2. This finger therefore comes, when passing the fifth, to select the command line fifth-reverse then move

  the dog 4 and the axis 8 in the direction of the fifth speed.

  The fork 7, integral with the axis 8 via the lug 15, follows the said axis in its movement towards the fifth speed. Indeed, in this direction of movement, the end 15a of the tenon abuts against the inclined face 12b of the notch 12. The tenon 15 then tends to rise along this inclined face. However, the end 15b of said tenon immediately comes

in abutment against axis 6.

  In this way, the post 15 cannot climb along the inclined face 12b and is held in the lowered position in the slot 14 and in the notch 12. Any transverse mobility of the post in the slot 14 is eliminated. The post is therefore integral, in longitudinal displacement, with the axis 8, as with the fork 7. This post is in fact kept pressed by the axis 6 in the notch 12 of the axis 8 during the passage of the gear ratio. forward. Thus, when moving this axis 8, towards the fifth speed, the

  pin 15 is also driven and in turn drives fork 7.

  The end 15a of the post cooperates in this case with the notch 12 in the axis -6- 8, particularly with the inclined face 12b, and the end 15b of said post

cooperates with axis 6.

  The movement of the fork 7 of fifth allows that of the associated walkman in order to synchronize the speed of the speed pinion and that of the secondary shaft. The fork remains attached to axis 8 all the time

  from moving to fifth gear until returning to neutral.

  This longitudinal course towards fifth gear is determined by the billing system. In fact, the movement of the ball 18, from the cutting of neutral point in the axis 8, to the cutting of the fifth, corresponds to the

  useful stroke of said axis to allow engagement of fifth gear.

  FIG. 2C represents the position of the fork 7 when the reverse gear is engaged. To do this, the user acts on the external control of the gearbox which transmits the selected speed to the shift finger 2. This finger therefore comes, when changing from reverse gear, to select the command line fifth-reverse gear . The dog 4 and

  axis 8 are then driven to the reverse position.

  The lug 15, linked to the neutral point on the axis 8, in longitudinal displacement, via the notch 12 and the stop of its end 15b against the axis 6, moves in the same direction as said axis 8, towards reverse. The end 15a of said tenon, abuts against the inclined face 12a

  of the notch 12. The tenon 15 then tends to rise along this inclined face.

  In this case, the end 15b of the tenon moves away from the stop 13a of the notch 13, produced in the axis 6 and enters said notch. The rise of the end 15a along the pan 12a is therefore possible and the tenon 15 moves transversely, upwards, in the lumen 14. The end 15a

  is released, at the end of the climb, from the notch 12 and abuts against the axis 8.

  The pin 15, having been released from the notch 12, the axis 8 and the fork 7 are therefore no longer integral. Thus, the longitudinal displacement of the axis 8 7- towards the reverse gear is not transmitted to the fork 7 which remains in its neutral position. In this way, the movement of the fork 7 from fifth to a fictitious sixth speed when passing the step

  rear is avoided, said fork disengaging in this direction of movement.

  This avoids unnecessary movement of this range within the

gearbox.

  The pin 15 is kept pressed into the notch 13 of the axis 6, by the second axis 8, when shifting from reverse, so as to immobilize the fork 7 with respect to this axis 6. This pin 15 remains therefore outside the notch 12 all the time of the movement towards the reverse and until returning to neutral where the end 15a descends, along the inclined face 12a, in said notch. This movement corresponds to the useful travel for actuating the reverse rocker 10, via the

control finger 9.

  The longitudinal displacement of the axis 8, in the hub 71 of the fork 7, is stopped when the ball 18 of the billing system cooperates with the cutting of said axis which corresponds to the operating position

rear engaged.

  The internal gearbox control according to the invention therefore provides a fork carrying a stop element, movable transversely to the fork axes and cooperating with notches in the latter, so as to release said fork from its axis during passage reverse gear. When shifting forward, the fork is made integral with its axis, in longitudinal displacement, and allows the engagement of the corresponding speed. The displacement of the tenon 15 inside the lumen 14 allows the

  joining or releasing the fork and the axle.

  The internal gearbox control in accordance with the invention therefore saves space, the space necessary to move the fifth gear to a fictitious sixth speed, when

engaging reverse gear.

  Of course, the invention is not limited to the embodiment described above but encompasses any internal control of a mechanical gearbox including a fork, linked to an axis of a gear line comprising reverse gear and another speed. , is released from its axis during

shifting from reverse.

9-9.

Claims (6)

  [1] Internal gearbox control comprising an internal control pin (1) connected to the vehicle's gearshift lever, carrying a passing finger (2) cooperating with at least two dogs (3, 4) respectively secured to 'a first speed control axis (6), and a second fork axis (8) (7) controlling the passage of a forward gear and a reverse gear, characterized in that said fork (7) moves with said second axis (8) to engage said forward gear, but is freed from it when engaging the reverse.   [2] Internal control according to claim 2, characterized in that the fork (7) carries a stop element (15), movable transversely to the fork axes (6, 8), cooperating with notches (12, 13) in the latter so as to release said fork   of its axis (8) when shifting from reverse.   [3] Internal control according to claim 2, characterized in that the stop element (15) is held pressed in by the first axis (6) in a notch (12) in the second axis (8) when the gear is shifted of forward.   [4] Internal control according to claim 2 or 3, characterized in that the stop element (15) is kept pressed into a notch (13) of the first axis (6), by the second axis (8), during of the shift from reverse, so as to immobilize the fork (7) with respect to said first axis (6).   [5] Internal control according to one of the preceding claims,   characterized in that the spacing of the two axes (6, 8) is less than 10- the total length of the stop element (15), to prevent it from   escape simultaneously from the two notches (12, 13).   [6] Internal control according to one of the preceding claims,   characterized in that the stop element (15) is engaged in a   light (14) passing through the hub (71) of the fork (7).