FR2805020A1 - Vehicle gearbox comprises locking finger which prevents engagement of non-selected forks, locking key can tip between two stops so rear gear fork activation causes limited displacement of other forks - Google Patents

Abstract

The gearbox comprises a locking key (7) whose locking finger (71) prevents the non-selected forks (31,32) by the change finger (41) of the gear selection rod (4) from being engaged. To make change to the rear gear more easy the locking key can tip between two stops (81,82) so that the activation of the rear gear fork causes a limited displacement of the other forks and brings together the associated synchronization parts (6120,6240) which in turn causes a braking of the engine shaft.

Description

The present invention relates to a gearbox with several forward gears and at least one reverse gear ratio, of the type that traditionally equips motor vehicles, as well as a method for optimizing the operation of such a gearbox. gearbox.

More specifically, the present invention relates in particular to a gearbox comprising at least: a housing; a motor shaft; a receiver shaft extending along a first axis in the housing; a plurality of interconnection sleeves mounted selectively movable in translation on the receiving shaft, with respect to which they are fixed in rotation; a series of pinions driven in rotation by the drive shaft, mounted idle on the receiving shaft, each of which is selectively rotatably connected to the receiving shaft by displacement of an associated clutch sleeve, selectively put in mesh with this pinion, these gears defining respective gear ratios comprising several forward gears and a reverse gear; timing rings each of which is interposed between an adjacent pinion and the associated clutch sleeve, for braking, in an approach position of the associated clutch sleeve, a possible relative rotational movement of this sleeve and the adjacent pinion before meshing them ; a plurality of forks each of which is selectively actuated to move one of the clutch sleeves; a set of brackets for actuating the forks and correspondingly controlling the interconnection sleeves, these butts being aligned at rest along a second axis, substantially perpendicular to the first; a selection rod extending parallel to the second axis and carrying a transverse cam extended by a passage finger, said rod being movable in translation parallel to the second axis for selectively placing the finger passage in a selected one of the set of sticks and being rotatable about itself, in first and second directions, for selectively moving the selected stock, via the finger, in first and second respective directions opposite to each other and whose first moves this stick from a neutral position to a commitment position of a selected ratio; a locking key mounted free to rotate on the selection rod, with respect to which this key is fixed in translation, this key comprising at least one locking finger engaged in all the butts with the exception of the selected stock, to prevent unselected sticks from reaching their engagement position; first and second stop members fixed relative to the housing for stopping the locking key in rotation relative to the housing during respective rotational movements of the selection rod in the first and second directions; and a blasting installed between the locking key and the cam to define at least a first energy-stable position of the passage finger relative to the key, for which the selected stick is in the neutral position.

Although gearboxes of this type have been known and used for a long time, they continue to be developed in order to increase their performance, particularly with a view to greater maneuverability and longer life.

The invention lies in this context and aims to provide a gearbox which, although requiring no structural complication, no increase in size or additional parts, allows a safer, more flexible and more silent reverse.

To this end, the gearbox of the invention, furthermore in accordance with the generic definition given in the preamble above, is essentially characterized in that the first and second stop elements stop the locking key in rotation. relative to the housing in respective first and second respective rotational positions, in that the reverse gear is engaged by selecting a first one of the hooks and placing it in its engaged position by rotation of the selection rod in the first direction of rotation, and in that the locking key, when it rests on the first stop element, separates the unselected brackets from their neutral position and correlatively places in their approach position the clutch sleeves controlled by the unselected brackets, which results in braking of the drive shaft before engaging the reverse gear re.

In addition, it may be advantageous to provide that the blasting also defines at least a second energy-stable position of the passage finger with respect to the key, in which the reverse gear is engaged, and for which the locking key rests on the second stop element.

The invention also relates to a method of selecting a reverse ratio in a gearbox provided with progressive meshing means which are controlled by respective sticks forming a set of sticks, and which act gradually between an inactive position and a full meshing position passing through a non-meshing torque passage position, which method comprises a main operation of moving, from a neutral position to an engagement position, a selected butt in the set of butts; .

The method of the invention is essentially characterized in that it comprises at least a first annex operation, concomitant with an initial phase of the main operation, and consisting of moving from their neutral position at least some unselected sticks up to to correlatively place the progressive meshing means controlled by these non-selected sticks in their position of passage of torque without meshing.

In its preferred embodiment, this method may also comprise at least one second annex operation, concomitant with a final phase of the main operation, and consisting in replacing in their neutral position the unselected brackets that have been removed from this neutral position. by the first annex operation. Other features and advantages of the invention will emerge clearly from the description which is given below, by way of indication and in no way limiting, with reference to the accompanying drawings, in which - Figure 1 is a partial sectional view of a standard gearbox, in this case having four forward gears, this view making it possible to generally identify the elements to which the invention relates more specifically; FIG. 2 is a perspective view of details that are not visible in FIG. 1, and relating to a box with five forward gears, embodying the invention; FIG. 3 is a perspective view similar to FIG. 2, but corresponding to a different observation angle; - Figure 4 is a schematic view of elements of a gearbox according to the invention, observed in a neutral or inactive position; - Figure 5 is a schematic view of elements of a gearbox according to the invention, observed in a transient position; - Figure 6 is a schematic view of elements of a gearbox according to the invention, observed in a position of engagement of the reverse gear; and FIG. 7 is a partial perspective view of a gearbox with five forward gears, in accordance with the invention, but whose fifth gear range has been omitted to improve the readability of this figure.

The invention generally relates to gearboxes in particular for use on land motor vehicles.

As known to those skilled in the art, a gearbox has the function of connecting, by a selected ratio in a set of predetermined ratios, the angular speed of rotation of the vehicle wheels to the angular speed of rotation of the engine who drives this vehicle.

Most gearboxes today offer five forward gears and a reverse gear ratio, the invention being however not at all limited to this configuration and for example being applicable to four-speed gearboxes. forward and reverse gear, as shown in Figure 1.

In any case, the invention is at least applicable to gearboxes which, as shown in particular in FIGS. 1 to 4, essentially comprise. a casing C; a motor shaft 1; a receiver tree 2; forks 30a, 30b, 31, 32 actuated by butts 300, 310, and 320; a selection rod 4 carrying a transverse cam 40 extended by a passage finger 41; interconnection sleeves 51, <B> 52; </ B> of the gears such as 11 to 14 and 21 to 24; synchronization rings 611, 612, 623, 624 each of which is interposed between an adjacent pinion 21 to 24 and the associated clutch sleeve 51, 52; a locking key 7 comprising at least one locking pin 71; stop members 81, 82 for stopping the locking key 7 in rotation; and a blasting 9 installed between the locking key 7 and the cam 40 of the selection rod 4. The driving shaft 1 and the receiving shaft 2 are supported by the casing C, parallel to each other, receiving shaft 2 extending along an axis X.

The forks 30a and 30b, which in the example illustrated in FIGS. 2 and 3 serve respectively to select the fifth forward gear ratio and the reverse gear, are controlled by the same butt 300, which can be moved in the direction D1 or following. the reverse direction D2, from its neutral position illustrated in Figures 2 and 3.

The fork 31, controlled by the stick 310, serves to select the first or the second forward gear, depending on whether the stock 310 is moved in the direction D1 or in the reverse direction D2, from its neutral position shown in FIGS. 2 and 3.

Finally, the fork 32, controlled by the stick 320, is used to select the third or fourth forward gear, according to whether the stick 320 is moved in the direction D1 or in the reverse direction D2, from its neutral position illustrated Figures 2 and 3.

Moreover, as shown in these same Figures 2 and 3, the butts 300, 310, 320, when in their neutral position, ie at rest, are aligned along a second axis Y perpendicular to the X axis.

The selection rod 4 extends parallel to the axis Y and can at will undergo firstly a translational movement parallel to the Y axis, for placing the passage finger 41 in any crosse selected in the set of butts 300, 310, 320, for example in the butt 300 associated with the fork 30b reverse gear, and secondly a rotational movement on itself in two opposite directions from each other S1, S2 (Figure 5), to move correlatively, thanks to the passage finger 41, the selected handle parallel to the axis X and following one or other of the directions D1 and D2 (Figures 2 and 5). More specifically, a movement of the rod 4 in the direction D1 makes it possible to move the selected stick from its neutral position to a first engagement position, and a movement of the rod 4 in the reverse direction D2 makes it possible to bring back the selected stick, from his first engagement position to his neutral position.

Similarly, a movement of the rod 4 in the direction D2 makes it possible to move the selected stick from its neutral position to a second engagement position, and a movement of the rod 4 in the reverse direction D1 makes it possible to bring back the selected butt. from its second engagement position to its neutral position.

The clutch sleeves 51, 52 are mounted fixed in rotation but movable in translation, along the X axis, on the receiving shaft 2, each sleeve 51, 52 being controlled by a corresponding fork 31, 32 and therefore, ultimately, by moving a determined stick in a determined direction, from the neutral position of this stick.

The pinions comprise pinions, such as 11 to 14, carried by the drive shaft 1, and pinions, such as 21 to 24, carried by the receiving shaft 2, the pinions of the receiving shaft being rotated by those of the motor shaft 1.

In general, the pinions of the receiving shaft 2 are mounted idle on this receiving shaft 2, each pinion such as 21 to 24 can be secured in rotation through an associated clutch sleeve 51, 52, set meshing with this pinion by moving the corresponding fork 30a, 30b, 31, 32 to its engagement position.

Traditionally, the pinions of the receiving shaft 2 mesh directly with the pinions of the motor shaft 1 for all gear ratios, R1 to R4, while the pinion (not shown) of the receiving shaft and the pinion (not shown) of the motor shaft by which these shafts are coupled to each other for the RO reverse gear meshes with each other only through a pinion additional, and only when reverse gear is engaged.

As shown in FIG. 1, each of the synchronization rings 611, 612, 623, 624 is interposed between an adjacent pinion, such as 21 to 24, and the associated clutch sleeve 51, 52, and has the function of braking, as soon as that the associated clutch sleeve adopts an approach position relative to the adjacent gear, any possible relative rotational movement of the sleeve and the adjacent gear before meshing with each other.

The locking key 7 is mounted free to rotate and fixed in translation on the selection rod 4, the locking finger 71 carried by this key moving with it along the Y axis.

More specifically, the locking pin 71 is shaped and arranged to engage in the unselected brackets and prohibit them from reaching their engagement position, the sticks 310 and 320 are therefore for example kept away from their actuating position when the selected stick is the butt 300 which is intended to actuate either the fifth gear fork 30a or the reverse gear fork 30b.

The stop elements 81, 82 are fixed relative to the casing C and their function is to stop the locking key 7 in rotation relative to the casing C when the selection rod 4 undergoes respective rotational movements along the directions S1 and S2.

Finally, the blasting 9 installed between the locking key 7 and the cam 40 has the function of defining at least a first energy-stable position of the passage finger 41 relative to the key 7, for which the selected stick is in the neutral position. By convention, the expression "energy-stable position" here designates a relative position adopted by two elements, in this case the passage finger 41 and the key 7, that these two elements can not leave spontaneously, but that they can not on the contrary leave only with a certain expenditure of energy.

According to a first main aspect of the invention, the first and second stop elements 81 and 82 stop the locking key in rotation relative to the casing C in different respective rotational positions, the first of which is illustrated in FIG. 5, and the second in Figures 4 and 6.

By convention, the directions S1 and S2 previously mentioned are defined so that the first direction of rotation S1 is that in which the selection rod 4 must be rotated, after insertion of the passage finger 41 in the butt 300, for place this stick in one of its two engagement positions which allows to control the fork 30b reverse gear, and to engage correlatively reverse gear.

According to the second main aspect of the invention, the locking key 7, when it rests on the first stop element 81, separates the unselected brackets 310 and 320 from their neutral position, and correlatively places them in their approach position. the clutch sleeves 51, 52 controlled by these non-selected sticks.

Under these conditions, the motor shaft 1 is braked by the synchronization rings 612 and 624 before the reverse gear is engaged, which allows this engagement in ideal conditions.

Preferably, the blasting 9 also defines at least a second energy-stable position of the passage finger 41 with respect to the key 7, illustrated in FIGS. 4 and 6, in which the reverse gear is engaged, and for which the key of FIG. locking 7 rests on the second stop element 82.

The operation of the device of the invention will be more readily understood with reference to FIGS. 4 to 6.

Figure 4 shows the device at rest, that is to say in a configuration for which all the sticks, and correlatively all the forks, are in their neutral position.

In this configuration, the locking key 7 rests on the second stop element 82 and the blasting 9 cooperates with a cutout 401 of the cam 40 to place the passage finger 41 in its neutral position.

Thus, although the passage finger is disposed in a selected stock, for example the butt 300 associated with the forks 30a and 30b, these forks 30a and 30b are themselves in their neutral position, while the forks 31 and 32 associated with the unselected brackets 310 and 320 are maintained in their neutral position by insertion of the locking pin 71 of the locking key 71 in these non-selected brackets 310 and 320.

Under these conditions, each of the teeth, such as 510 and 520, the clutch sleeves controlled by the forks 31 and 32 controlled by the unselected brackets 310 and 320 remain at a distance from the respective teeth, such as 6120 and 6240, the rings of synchronization 612 and 624 corresponding, and a fortiori distance of respective teeth, such as 220 and 240, gears 22 and 24.

When, after insertion of the passage finger 41 into the butt 300 initially in the neutral position, the selection rod 4 is rotated in the first direction Sl in order to move the fork 30b correspondingly from its neutral position to its engagement position. of the reverse ratio, the support of the blasting 9 on the cut 401 of the cam 40 causes the rotation of the locking key 7 by the selection rod 4 in the same direction S1.

During the movement of the locking key 7, the corresponding movement of the locking pin 71 engaged in the unselected brackets 310 and 320 causes the translation of the associated forks 31 and 32, for example along the axis 39 of the fork 30a. which in this case serves as a guide axis.

The rotation of the locking key 7 and the translation of the forks continues until the key 7 meets the first stop element 81, this position being that shown in FIG. 5.

In this configuration, the teeth such as 510 and 520 of the clutch sleeves controlled by the unselected forks 31 and 32, although not meshing with the respective teeth such as 220 and 240 of the gears 22 and 24, come into contact with the teeth. teeth such as 6120 and 6240 synchronization rings 612 and 624 corresponding.

This contact causes the appearance of a torque exerted between the motor shaft 1 and the receiver shaft 2 via at least two pairs of gears such as 22 and 12, and 24 and 14.

However, insofar as these pairs of gears correspond to different gear ratios R2 and R4, and where no relative rotational speed of the shafts 1 and 2 allows these ratios R2 and R4 to coexist, the forces exerted by the contact interconnection sleeves and synchronizing rings cause rapid and efficient braking of the rotational movement of the motor shaft 1.

When the rotation of the selection rod continues beyond its position shown in FIG. 5, the cut 401 of the cam 40 escapes the blasting 9 and the passage finger 41 can be moved to its position shown in FIG. 6, for which the stock 300 places the fork 30b of reversing gear in a position where this fork engages the gear ratio.

In this position of the butt 300, the blasting 9 is supported on a second cut 402 of the cam 40, which defines a second energy-stable position of the passage finger 41 relative to the key 7, for which the key 7 rests on the second abutment element 82, the unselected brackets 310 and 320, and the associated forks 31 and 32, then being returned to their neutral position by the locking pin 71, as shown in Figure 6.

As will be understood by those skilled in the art from the foregoing, the invention thus also relates to an improved method of selecting a reverse gear ratio for a gearbox with progressive meshing members such as than those together constitute the clutch sleeves 51 and 52 and the timing rings 611, 612 and 623, 624 which are associated with these sleeves.

These progressive meshing members are generally controlled the associated butts such as 300, 310, and 320, through the forks such as 30a, 30b, 31 and 32.

Moreover, these drive members act progressively between an inactive position shown in FIG. 4 and a complete meshing position illustrated in FIG. 6 for the reverse gear, passing through a torque passing position without visible meshing on the figure 5.

Conventionally, this method comprises a main operation which consists in moving, from its neutral position to its engagement position, the butt 300 which controls the passage of the reverse gear.

The method according to the invention differs from the known method in that it furthermore provides, at the beginning of the driving phase of the reversing control stick towards its position of engagement of the reverse gear, an operation consisting, as shown in FIG. 5, in displacing the unselected brackets 310 and 320 from their neutral position until the progressive meshing members 51, 52 and 611, 612, 623, 624, are controlled by these non-locking brackets selected, in their position of passage of torque without meshing, to cause a braking of the motor shaft 1.

Finally, the method according to the invention preferably provides, at the end of the drive phase of the reversing control stick to its engagement position, a second operation which consists, as shown in FIG. return to their neutral position the unselected sticks that were removed from this neutral position by the previous operation.

Claims (4)

<B> <U> CLAIMS </ U> </ B> 1. Transmission comprising at least one housing (C); a driving shaft (1); a receiver shaft (2) extending along a first axis (X) in the housing; a plurality of interconnection sleeves (51, 52) mounted selectively movable in translation on the receiving shaft (2), with respect to which they are fixed in rotation; a series of pinions (20 to 24) driven in rotation by the driving shaft (1), mounted idle on the receiving shaft (2), and each of which is selectively secured in rotation with the receiving shaft (2) by displacement of an associated clutch sleeve (51, 52), selectively meshing with this pinion (20 to 24), these pinions (20 to 24) defining respective speed ratios (RO to R4) comprising several gears forward (R1 to R4) and a reverse gear (RO); synchronization rings (611, 612, 623, 624) each of which is interposed between an adjacent pinion (21 to 24) and the associated clutch sleeve (51, 52), for braking, in an approach position of the sleeve of associated clutching, a possible relative rotational movement of this sleeve and the adjacent gear before meshing; a plurality of forks (30, 31, 32) each of which is selectively actuated to move one of the jaw clutch sleeves; a set of brackets (300, 310, 320) for actuating the forks and correspondingly controlling the interconnection sleeves, these sticks being aligned at rest along a second axis (Y), substantially perpendicular to the first (X); a selection rod (4) extending parallel to the second axis (Y) and carrying a transverse cam (40) extended by a passage finger (41), this rod (4) being movable in translation parallel to the second axis (Y ) for selectively placing the passage finger (41) in a selected one of the set of sticks, and being rotatable on itself, in first and second directions (S1, S2), for selectively moving the selected butt. , via the passage finger (41), in first and second respective directions (D1, D2) in inverse of each other and whose first (D1) moves this stick from a neutral position to a commitment position of a selected report; a locking key (7) mounted free to rotate on the selection rod (4), with respect to which this key is fixed in translation, this key (7) comprising at least one locking finger (71) engaged in the set of sticks with the exception of the selected stick, to prevent the unselected sticks from reaching their engagement position; first and second stop members (81, 82) fixed with respect to the housing (C) for stopping the locking key (7) in rotation relative to the housing (C) during respective rotational movements of the selection rod ( 4) in the first and second directions (S1, S2); and a blasting (9) installed between the locking key (7) and the cam (40) to define at least a first energy-stable position of the passage finger (41) relative to the key (7), for which the stick selected is in a neutral position, characterized in that the first and second stop members (81, 82) stop the locking key in rotation relative to the housing (C) in respective first and second respective rotational positions, in that the reverse gear is engaged by selecting a first (300) of the hooks and placing it in its engaged position by rotation of the selection rod (4) in the first direction of rotation (S1), and in that the locking key (7), when it rests on the first abutment element (81), separates the non-selected brackets from their neutral position and correlatively places in their approach position the interconnection sleeves (51, 52) controlled by the not selected sticks, which results in a braking of the motor shaft (1) before the engagement of the reverse gear. 2. Gearbox according to claim 1, characterized in that the blasting (9) also defines at least a second energy-stable position of the passage finger (41) relative to the key (7), wherein the gear ratio rear is engaged, and for which the locking key (7) rests on the second stop element (82). A method of selecting a reverse gear ratio in a gearbox having progressive meshing means (51, 611, 612; 52, 623, 624) which are controlled by respective butts forming a set of butts ( 300, 310, 320), and which progressively act between an inactive position and a full meshing position through a torque passing position without meshing, which method comprises a main operation of moving from a neutral position to a at an engagement position, a butt (300) selected from the set of brackets, characterized in that it comprises at least a first annex operation, concomitant with an initial phase of the main operation, and consisting in moving their neutral position at least some unselected sticks (310, 320) to correlatively place the progressive meshing means (51, 611, 612; 52, 623, 624) controlled s by these sticks not selected in their position of passage of torque without meshing. 4. Method according to claim 3, characterized in that it further comprises at least a second annex operation, concomitant with a final phase of the main operation, and consisting in replacing in their neutral position the unselected brackets that have been away from this neutral position by the first annex operation.