FR2819569A1 - Motor vehicle gearbox internal control mechanism has set of flat bars extending parallel to sliding rods and operated by gear changer - Google Patents

Abstract

The mechanism, operated by a control shaft (1) and transverse selector peg (9), consists of a set of flat bars (11 - 14) extending parallel to sliding rods (19 - 22) with forks (15 - 18) to engage with gear claw couplings. The bars are located in a housing (7) inside the gearbox and are actuated individually by the selector peg to move in a straight direction relative to the gearbox casing and engage with the forks by notches in their lower edges.

Description

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 The present invention relates to an internal control device for a gearbox for a motor vehicle.

 Such a device is known comprising, housed in the gearbox casing, a control pin carrying a transverse gear shift finger which can first be selectively engaged, by sliding the pin, in one of several juxtaposed gear engagement elements respectively by means of parallel sliding rods in the casing to which the forks for moving pinions or clutches are secured, engaging or disengaging the various ratios of the gearbox, and then driving the element selected by rotation of the axis, so as to carry out the engagement of a report.

 According to this known device, the juxtaposed elements for engaging ratios, called nuts, are integral with the forks, by welding or riveting, and although such an arrangement is economical, it brings many problems linked to dispersions in the manufacture of nuts and the positioning of the forks in the gearbox and clutch housings by means of their axes or sliding rods in bosses as well as their angular positioning in the sleeves of synchronizers subject to radial deflections and relatively large cumulative dispersions .

Such dispersions pose many problems.
Thus, the positioning dispersions of the nuts on the forks as well as the angular dispersions brought about by the positioning recoveries on the sleeves of the synchronizers, impose a certain clearance between the gearshift nuts so as not to disturb their primary sliding function. These clearances between nuts are detrimental to the ergonomics of the selection passage grid because they impose a reduction in the passage chamfers at an angle because

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 the sum of the clearance and the chamfer must be less than the thickness of the passing finger minus its chamfers, otherwise the passing finger could get caught between two nuts.

 In first, second, fifth or sixth gear engaged, the shifting finger, pushed by the selection return springs, comes to rest on the third and fourth gear shifting fork nuts. In the case of a significant manufacturing dispersion of the synchronizer sleeve, the hubs and the shaft supporting the third / fourth speed synchronizer, this synchronizer could have a large beat during its rotation and transmit these beats via of the angular resumption of positioning of the third / fourth speed range, a beat according to the same frequency as the speed of rotation of the sleeve. This beat will be transmitted directly to the gearshift lever knob in the vehicle, amplified by the reduction of the control by approximately four times.

 In addition, the shifting finger being positioned relative to its internal control module comprising the selection recall elements, neutral position positioning and selection stop while the nuts are linked to the forks, themselves positioned by the casing and the sleeves of synchronizers, there is no direct relationship between the selection changeover grid produced by the internal control module and the grid produced by the gearshift nuts. Under these conditions, the number of dimensions to be obtained to obtain the connection between these two grids implies more operating clearance and is therefore detrimental to the operating precision directly felt in terms of ergonomics at the knob of the gear shift lever.

 Finally, in the case where the driver of the vehicle gives an effort in gear selection while the

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 first, second, fifth or sixth gear reports are engaged or during a second / third or fifth / sixth gear shift, that is to say so-called "bias" shifts, a selection effort may be transmitted, by means of the speed control, with the passing finger itself resting on the third / fourth speed fork nut, at this same nut and bringing towards a bending of the latter, then amplifying the friction of the fork pads on his sleeve.

 The object of the present invention is to eliminate the above drawbacks by providing an internal control device for a gearbox comprising, housed in the casing thereof, a control pin carrying a transverse gear shift finger. which can firstly be selectively engaged, by sliding the axis, in one of several juxtaposed engagement elements of reports by means of respectively sliding parallel rods to which dog clutch movement forks are made integral making it possible to carry out the engagement or disengagement of the different ratios of the gearbox, and then driving the selected element by rotation of the axis, so as to achieve the engagement of a ratio, and which is characterized in that the elements juxtaposed engagement plates respectively include flat bars extending parallel to the sliding rods and can be driven each selectively in rectilinear translation relative to the casing by the shifting finger, each bar comprising at its lower edge a notch substantially in the shape of a large U passing through the wall of the bar and in which is housed a projection of conjugate form of a fork corresponding, extending transversely to the bar.

 Advantageously, the shifting finger and the gear engagement bars are housed in a

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 housing fixed to the housing, the bars being mounted movable in translation relative to the housing by means of two longitudinally spaced transverse axes integral with the housing and passing respectively through two longitudinal slots of each bar.

 The bars include identical juxtaposed outgrowths located above the bars and forming for each bar two legs longitudinally spaced in half crescent moon supporting a cylindrical part of the shifting finger ensuring the blocking in translation of the bars, the part cylindrical comprising a window on either side of the finger allowing the drive in translation in one direction or the other of the selected bar by making penetrate one or the other of the two tabs of the bar in the corresponding window according to the direction of rotation of the control axis.

 The control axis is rotatably supported in the housing by two end bearings and positioned axially thereof by a selection return mechanism housed in the housing.

 The forks extend with their respective projections respectively in planes perpendicular to the bars.

la figure 2 est une vue en perspective du dispositif de commande suivant la flèche II de la figure 1 ; The invention will be better understood, and other objects, characteristics, details and advantages thereof will appear more clearly in the explanatory description which follows, made with reference to the appended drawings given solely by way of example illustrating an embodiment. of the invention and in which: FIG. 1 is a perspective view of the gearbox control device according to the invention;

Figure 2 is a perspective view of the control device according to arrow II of Figure 1;

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 Figure 3 is a perspective view of the control device of Figure 1 without the rods and forks thereof; - Figure 4 is a perspective view similar to that of Figure 1 without the housing housing the shifting finger carried by the control shaft and gear engagement nuts; - Figure 5 is a perspective view similar to that of Figure 4 and showing only the gear engagement nuts associated respectively with the rods and displacement forks; Figure 6 is a perspective view showing only the rods and their associated displacement forks of the control device; - Figure 7 is a perspective view of a speed change finger of the control device of Figure 1; and - Figures 8A and 8B are schematic views from above of the gear engagement nuts and the passing finger according to the prior art and the invention respectively.

 Referring to the figures, the control device of a gearbox for a motor vehicle comprises a control pin 1 housed in the casing (not shown) of the gearbox and connected by a bent part 2 to the selection lever and shifting of a gearbox gear designed in this case to offer seven transmission ratios including reverse gear and six forward gears or "gears" 1 to 6.

 The control axis 1 can slide in two bearings 3, 4 secured respectively to two vertical parallel walls 5, 6 of a support 7 fixed to the casing of the gearbox by fixing screws 8.

 The control axis 1 carries a passage finger assembly 9 which is fixed to the control axis 1 by a pin (not shown) extending radially to

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 through a cylindrical tubular part 9a radially integral with the external surface of a partially cylindrical wall 10 from which the passage finger 9b projects radially so that the end of the finger 9b is located at the level of a certain number of elements 11, 12, 13,14 which are movable perpendicular to the axis 1, as will be seen later.

entraîner des fourchettes 15, 16, 17 et 18 solidaires respectivement de tiges 19, 20, 21, 22 montées coulissantes suivant leurs propres axes relativement au carter de la boîte de vitesses. Les fourchettes 15 à 18 peuvent déplacer des manchons de crabotage pour réaliser l'engagement ou le dégagement des différents rapports de la boîte de vitesses. Elements 11-14, often called nuts, can

drive forks 15, 16, 17 and 18 respectively fixed to rods 19, 20, 21, 22 mounted sliding along their own axes relative to the gearbox housing. The forks 15 to 18 can move the clutch sleeves to engage or disengage the different ratios of the gearbox.

When the control axis 1 is moved by sliding, the passage finger 9b can be selectively engaged with one of the selected nuts 11-14 and, by rotation of the control axis 1, the selected nut is driven to produce the passage of one of the two reports associated with the nut.

A mechanism 23 is associated with axis 1 for the. return to the neutral position after sliding for the selection of a gear and is generally constituted by two helical springs surrounding the axis 1 arranged coaxially respectively on either side of the passing finger 9 and compressed separately according of the gear engaged via a ring arranged on the control shaft.

 This mechanism is well known in itself and is described in detail in French patent application No. 2,778,220.

 The forks 15, 16 and 17 are intended for the passage of the fifth / sixth speeds, third / fourth speeds and first / second speeds respectively, while the fork 18 is intended for the

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passage de la marche arrière sous la commande du bras inverseur de marche arrière 24 monté pivotant relativement au carter autour d'un axe vertical 25. La fourchette 15 est actionnée par la noix 13, la fourchette 16 par la noix 12 et la fourchette 17 par la noix 11, tandis que la noix 14 actionne la fourchette 18.

passage of reverse gear under the control of the reverse gear reversing arm 24 pivotally mounted relative to the casing about a vertical axis 25. The fork 15 is actuated by the nut 13, the fork 16 by the nut 12 and the fork 17 by the nut 11, while the nut 14 actuates the fork 18.

 According to the invention, the assembly constituted by the return mechanism 23, the passage finger 9 and the part of the axis 1 supporting the finger 9 is housed in a housing constituting the support 7 secured to the gearbox casing .

 This housing thus comprises the two vertical parallel walls 5, 6 connected at their upper ends by a horizontal upper wall 26 and are extended at their lower parts respectively by two vertical walls spaced closer 27, 28 between which the nuts 11- are slidably mounted 14. The latter are respectively constituted by juxtaposed flat bars which can be vertical, horizontal or inclined and which extend parallel to the sliding rods 19 to 22 and which can each be selectively driven in rectilinear translation relative to the housing 7 by the gear shift finger 9. To this end, each bar 11; 12; 13; 14 comprises two openings 29, 30, only the two openings associated with the reverse passage bar 14 being shown, extending longitudinally spaced apart from the bar by crossing the wall of the latter. In the neutral or neutral position of the speed change lever, the lights 29, like the lights 30, of the bars 11 to 14 are located opposite one another, thus forming a single light passing through all the bars. As is clear from FIG. 5, the slots 30 located behind the bars 11 to 14, that is to say opposite to the connection of these bars to the different forks as will be seen later, open at the ends

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correspondantes des barrettes. Pour permettre le déplacement en translation de chaque barrette sélectionnée, deux axes transversaux 31, 32 sont fixés à leurs extrémités aux deux parois inférieures 27, 28 dans des bossages correspondants 33 et traversent respectivement les lumières 29,30. En position médiane de point mort des barrettes 11 à 14, chaque axe 31,32 est situé sensiblement au milieu des lumières correspondantes 29,30 de façon que chaque barrette puisse se déplacer sélectivement dans un sens ou dans le sens opposé relativement aux deux axes transversaux 31, 32 suivant l'une des deux vitesses correspondantes à engager.

corresponding bars. To allow the translational movement of each selected bar, two transverse axes 31, 32 are fixed at their ends to the two lower walls 27, 28 in corresponding bosses 33 and pass through the slots 29.30 respectively. In the middle neutral position of the bars 11 to 14, each axis 31,32 is located substantially in the middle of the corresponding slots 29,30 so that each bar can move selectively in one direction or in the opposite direction relative to the two transverse axes 31, 32 according to one of the two corresponding speeds to be engaged.

 Each bar 11,14 has at its lower edge a notch opening substantially in the shape of a U 34, only the notches 34 associated respectively with the bars 13 and 14 being visible in the figures. Each notch 34 passes through the wall of the corresponding bar and a projection 35 of shape conjugate to the notch 34 and integral with each fork 15 to 17 is housed in the notch 34 extending transversely to the corresponding bar 11 to 13.

More specifically, the fifth / sixth gear engagement fork 15 comprises a lug 15a integral with the fork in the same plane perpendicular to the associated rod 19 and extending perpendicular to the rod 19 opposite the fork 15. The tab 15a has at its upper edge a projection 35 of substantially parallelepiped shape engaging through the notch 34 of the bar 13. The two forks 16, 17 associated respectively with the bar 12 for passing third / fourth gear and at the bar 11 for the passage of the first / second gears, have on their rings 16a, 17a for fixing respectively to the two rods 20, 21 the two respective projections 35, each substantially in the shape of a rectangular parallelepiped engaging through the notch

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34 de la barrette correspondante 12, 11. Comme pour la saillie 35 de la fourchette 15, les saillies 35 des fourchettes 16, 17 sont réalisées en une seule pièce avec celles-ci dans un même plan perpendiculaire aux tiges associées 20, 21. Enfin, la fourchette de marche arrière 18 comporte également une saillie 35 sensiblement de forme parallélépipèdique réalisée en une seule pièce avec la fourchette dans un même plan perpendiculaire à la tige 22 et qui s'engage au travers d'une encoche 24a réalisée à l'extrémité du bras inverseur 24, dont l'extrémité opposée s'engage au travers de l'encoche 34 de la barrette associée 14 de passage de marche arrière.

34 of the corresponding bar 12, 11. As for the projection 35 of the fork 15, the projections 35 of the forks 16, 17 are produced in a single piece with these in a same plane perpendicular to the associated rods 20, 21. Finally , the reverse gear fork 18 also includes a projection 35 of substantially parallelepipedal shape made in one piece with the fork in the same plane perpendicular to the rod 22 and which engages through a notch 24a made at the end of the reversing arm 24, the opposite end of which engages through the notch 34 of the associated bar 14 for reversing.

 The rods 19-22 of the forks 15-18 are slidably positioned in the end bosses (not shown) made respectively in the gearbox housing and the clutch housing.

 Preferably, the forks 15-18 are produced from a flat sheet welded on their respective axes 19-22.

 As can be seen more clearly from FIG. 5, the bars 11-14 include identical protuberances 36, 37 which are juxtaposed and situated above the bars. Thus, each bar has two protuberances forming two longitudinally spaced opposite legs 36, 37, each having a half-crescent moon face 36a, 37a for supporting or supporting the cylindrical part 10 of the passage finger 9 In this way, the cylindrical part 10 this finger ensures the locking or interlocking in translation of the bars 11-14 in the neutral position of the gear change lever. The cylindrical part 10 has two windows 10a located on either side of the finger 9b in the same plane transverse to the axis of the assembly 9 and allowing the selected bar to be driven in translation in the appropriate direction by penetrating either of the two legs 36.37 of the bar

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 in the corresponding window according to the direction of rotation applied to the control axis 1, the cylindrical part 10 and its corresponding windows 10a having of course been previously positioned relative to the bar to be selected by sliding the axis 1.

 The structure of the assembly forming a passage finger with windows 10a as shown in FIG. 7 is known per se and need not be detailed further.

 The tabs 36, 37 of the bars define between them below the cylindrical part 10 of the assembly forming a finger 9 a recessed part for the passage of the finger 9b transversely to the bars.

 The operation of the control device of the invention is already apparent in part from the description which has been made above and will now be explained.

 When the driver of the vehicle wishes to select and switch to the first gear, he controls the displacement of the axis 1 in translation to cause the finger 9b to engage between the legs 36, 37 through the bars until they are between the two legs 36,37 of the bar 11 which is thus selected and, after rotation of the axis 1, the finger 9b causes the displacement in translation along its longitudinal axis of the bar 11 which acts directly on the corresponding fork 17 to move in translation the associated rod 21 so that the fork actuates the corresponding clutch sleeve for shifting the first gear.

 The displacement in translation along their own longitudinal axis of each of the other bars to select one of the two speeds associated with it is identical to that of the bar 11 and does not need to be detailed again.

 Due to the fact that all the parts comprising the control axis 1, the passage finger 9, the nuts 11-14, the selection return mechanism 23 and the guide bearings 3, 4 of the axis 1, allows to decrease the number of

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 dimensions connecting these parts so that the operating precision of the control device is improved.

 Many other advantages result from the design of the control device of the invention.

Thus, this device allows a reduction in the clearances between the passage nuts and, consequently, makes it possible to improve the values of the chamfer of bias passage N as illustrated in FIG. 8B relative to the values N of the device of the prior art of the FIG. 8A which shows that each value N of the prior device due to the play existing between the nuts is greater than the value N of the device of the invention of FIG. 8B, which makes it possible to obtain a leading end D of the finger passage 9 with a width less than that of the finger of the prior art. In this way, the ergonomics of shifting is improved. In addition, the control device is designed so as to improve the precision of the interlocking of the locking of the half-moon type passage nuts by reducing the number of dimensions between the passage finger and the nuts. The device also makes it possible to reduce the clearance of the passage finger between the passage nuts in selecting the engaged gears and therefore to improve the precision of the gear change grid, and consequently, to improve the ergonomics of passage. The device makes it possible to eliminate the bending forces on the selected passage nuts, and the radial forces on the forks, which makes it possible to provide a gain in reliability of the forks and a gain in precision of the gearshift grid. The device of the invention makes it possible to eliminate the anti-tilt fork for the fork having a long nut as is the case for the fifth / sixth gear shifting fork in the devices of the prior art. Such an anti-tilt fork generates, in the case of a gear change subjected to a selection effort in addition to the shift effort (bias shift), a hardness due to friction

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 of this anti-tilt fork on the corresponding fork axis. Finally, the device makes it possible to modify the gear shift grid because the shift nuts can be arranged, for example, with a reverse gear attached to the fifth / sixth shift nut instead of the first shift nut. / second speed. FIG. 5 shows that the decoupling of nuts 11-14 and forks 15-18 makes it possible to admit large dispersions of relative position along + x, -x; + z, -z so that these nuts only provide the following translation + y and -y.

 In short, the control device of the invention proposes to link the control nuts of the forks to the support box secured to the gearbox housing, instead of the forks as in the prior art, which allows direct quotation shift nuts on the shift finger in order to improve the accuracy of the shift / speed selection grid, to eliminate the forces transmitted during selection by the gear shift lever in the vehicle to the forks in the gearbox and eliminate the vibrations transmitted in selection by the synchronizers to the gearshift lever present in the vehicle.

Claims (5)

 CLAIMS 1. Internal control device for a gearbox comprising, housed in the casing thereof, a control pin (1) carrying a transverse gear shift finger (9) which can first be selectively engaged, by sliding the axis (1), in one of several juxtaposed elements (11 i 12 i 13; 14) for engaging the ratios by means of respectively sliding parallel rods (19; 20; 21 22) to which are joined to the forks (15 i 16 i 17; 18) for moving the dog clutch allowing the engagement or disengagement of the different ratios of the gearbox to be effected, and then driving the selected element by rotation of the axis (1 ), so as to carry out the engagement of a report, characterized in that the juxtaposed elements of engagement of reports (11-14) respectively comprise flat bars extending parallel to the sliding rods (19-22) and being able be trained ch acune selectively in rectilinear translation relative to the casing by the shifting finger (9), each bar (11-14) comprising at its lower edge a notch substantially U-shaped (34) passing through the wall of the bar and in which is housed a projection of conjugate shape (35) of a corresponding fork, extending transversely to the bar.  2. Device according to claim 1, characterized in that the gear shift finger (9) and the gear engagement bars (11-14) are housed in a housing (7) fixed to the casing, the bars being mounted movable in translation relative to the housing (7) by means of two longitudinally spaced transverse axes (31,32) integral with the housing (7) and passing through two spaced apart longitudinal slots (29, 30) of each bar, respectively. <Desc / Clms Page number 14>  3. Device according to claim 1 or 2, characterized in that the bars (11-14) comprise juxtaposed identical protuberances (36,37) located above the bars (11-14) and forming for each bar two legs longitudinally spaced in half crescent moon of support of a cylindrical part (10) of the speed change finger (9) ensuring the locking in translation of the bars, the cylindrical part (10) comprising windows (lofa) on both sides other of the finger (9) allowing the drive in translation in one direction or the other of the selected bar by making one or the other of the two tabs (36, 37) of the bar penetrate into the corresponding corresponding window the direction of rotation of the control shaft (1).  4. Device according to claim 2 or 3, characterized in that the control shaft (1) is rotatably supported in the housing (7) by two end bearings (3,4) and positioned axially therein by a selection recall mechanism (23) housed in the housing (7).  5. Device according to one of the preceding claims, characterized in that the forks (15-18) extend with their respective projections respectively in planes perpendicular to the bars (11-14).