EP3177856A1

EP3177856A1 - Gearbox for a motor vehicle

Info

Publication number: EP3177856A1
Application number: EP15753102.1A
Authority: EP
Inventors: Eric Schaeffer; Alexandre Deschamps
Original assignee: Technoboost SAS
Current assignee: Technoboost SAS
Priority date: 2014-08-05
Filing date: 2015-07-10
Publication date: 2017-06-14
Also published as: WO2016020590A1; FR3024760B1; FR3024760A1

Abstract

A gearbox for a motor vehicle comprising at least one coupling means (213, 223, 233) for coupling a shaft (1000, 1001) to a pinion mounted about said shaft (1000, 1001), said coupling means (213, 223, 233) being movable in translation, a control cylinder (100) movable in rotation to control the translation of said coupling means (213, 223, 233), a means (610, 910) for monitoring the angular displacement of the cylinder (100), a means (700, 800, 900) for observing if the control cylinder (100) is at a predefined angular position (θ0) predefined to initialise said monitoring means (610, 910), and a means (600, 900) for controlling the rotation of the cylinder (100) until the fact that the cylinder (100) is in said predefined angular position (θ0) is observed, characterised in that the gearbox further comprises means (261, 262, 263, 900) for disengaging the coupling means (213, 223, 233) from the cylinder (100) during the implementation of said means (600, 900) for controlling the rotation of the cylinder (100) until the fact that the cylinder (100) is in said predefined angular position (θ0) is observed, and re-engaging said coupling means (213, 223, 233) in the cylinder (100) in order to engage a gear ratio.

Description

GEARBOX FOR MOTOR VEHICLE

The invention relates to a control cylinder gearbox, an initialization method relating to such a gearbox, and a computer program for implementing the initialization method. [0002] A gearbox comprises a shaft on which free sprockets are mounted. This shaft is referred to as a secondary shaft, as opposed to the primary shaft that carries fixed gears. Each free gear defines with a fixed gear a gear ratio.

The free sprockets are freely rotatable vis-à-vis the corresponding secondary shaft except when a clutch and a synchronizer come to secure one of the pinions with the shaft to engage the corresponding gear ratio. The synchronizer is currently actuated by a fork movable in translation. The assembly formed by the claws, the synchronizer and the fork is a means of coupling the shaft and pinion.

The translation movement of the fork is given to it, in the systems which interest us here, by a control cylinder movable in rotation. The transformation of the rotation of the barrel in translation of the fork is performed using a track carried by the barrel, which is oriented to produce a cam effect (or ramp effect).

[0005] For example, such a system is known from the document FR 2 970 31 1. It is disclosed in this document that the track of the cylinder interacts with an actuating pin (or control stick) integral with the fork.

In known systems, when starting the engine, the angular position of the control cylinder is generally unknown. It is necessary to initialize this position, by actuating the rotating barrel and looking for a mark present on an angular sector thereof. However, the rotation of the barrel causes the successive passage of gear ratios, which is noisy, creates shocks, and wears the parts. More commitment failures can sometimes occur. Finally, the shift gears requires that the cylinder is rotated at a moderate speed, and the driver must wait until the initialization is finished before engaging the first gear. Thus, the vehicle is unavailable at startup for a disadvantageously prolonged time. [0008] FR2850441 discloses a gearbox with a control barrel, but this document does not indicate how to initialize the angular position of the control barrel.

The invention aims to solve these problems and proposes a gearbox for a motor vehicle comprising at least one coupling means for coupling a shaft to a pinion mounted around said shaft, said coupling means being movable in translation, a cylinder rotational control device for controlling the translation of said coupling means means for monitoring the angular displacement of the barrel, means for ascertaining whether the control barrel is at a predetermined angular position to initialize said tracking means, and means for controlling a rotation of the barrel until the fact that the barrel is at said predetermined angular position, characterized in that the box further comprises means for disengaging the coupling means of the barrel at least during the implementation of said means for controlling a rotation of the barrel until the observation that the barrel is at said predefined angular position completed and re-engage said coupling means in the barrel for engaging a gear ratio.

Thanks to these characteristics, it is possible to start the motor vehicle without loss of time, and without unnecessarily soliciting mechanical parts not involved in the initialization process of the control of the control cylinder. This results in extra comfort for the driver and increased service life for the mechanisms.

[001 1] For example, the means for determining whether the control cylinder is at a predetermined angular position comprises an on-off sensor and a witness placed on a section of the barrel, the all-or-nothing sensor identifying the witness.

The box may further comprise an electric motor for controlling the rotation of the barrel, the means for monitoring the angular displacement of the barrel comprising a sensor for monitoring the angular displacement of the barrel placed in the electric control motor.

The means for controlling a rotation of the barrel until the observation that the barrel is at said predetermined angular position can control a rotation in one direction and then in opposite direction to find twice the fact that barrel is at said position predetermined angle so as to increase the accuracy of the finding.

In one embodiment, once found that the barrel is at said predetermined angular position, the box is configured to control the rotation of the barrel. to an initial position at which the coupling means is again engaged in the barrel.

For example, said means for disengaging the barrel coupling means may comprise retractable nipples on order interacting, when they are not retracted, with a control track present on the surface of the barrel, and a control unit for order their retraction before initialization or replacement after initialization.

The invention also consists in a method of initializing an angular displacement tracking of a gearbox control cylinder for a motor vehicle, the box comprising at least one coupling means for coupling a shaft to a gearbox. pinion mounted around said shaft, said coupling means being movable in translation, said cylinder being movable in rotation to control the translation of said coupling means by means of a control track present on the surface of the cylinder, characterized in that the method comprising disengaging the barrel coupling means followed by a rotation control of the barrel until the fact that the barrel is at a predetermined angular position, to initialize said tracking, and subsequently, a reengagement of the means of coupling in the barrel to engage at least one gear ratio.

The invention also provides a computer program, which when implemented by a processor leads to the implementation of the steps of the method according to the invention.

The invention will be better understood, and other objects, features, details and advantages thereof will appear more clearly in the explanatory description which follows with reference to the accompanying drawings given solely by way of example illustrating a embodiment of the invention and in which: - Figure 1 shows a gearbox control cylinder;

- Figure 2 shows a coupling system of the shaft and sprockets of a gearbox comprising a control cylinder;

- Figure 3 shows the coupling system of the shaft and sprockets of a gearbox comprising a barrel, according to one embodiment of the invention.

- Figure 4 shows an aspect of an embodiment of the invention. In Figure 1, there is shown a control cylinder 100 of a motor vehicle gearbox. It is a generally cylindrical piece, of circular section and axis XX, and whose outer circumferential surface carries tracks, here three in number, referenced 1 10, 120 and 130. These tracks, which may have a U-shaped profile, are for example the result of a machining of the barrel material, and extend generally over a circumference thereof. They consist of different sections succeeding each other on successive angular sectors. Some sections extend in a plane perpendicular to the axis of the barrel, while other sections (ramps) extend in a plane inclined relative to the axis of the barrel. The cylinder 100 may be driven, relative to the housing of the gearbox, a rotational movement R about the axis XX, due to the action of an electric motor, for example. Each of the tracks 1 10, 120, 130 then constitutes a guide for a corresponding fork actuation nipple (or control stick). The forks are not shown in FIG. 1, but there is a distinction between the stud 21 1 which is guided in the track 1 10, the stud 221 which is guided in the track 120 and the stud 231 which is guided in the track 130.

Thus, three forks are controlled by the barrel 100. Nevertheless, the barrel 100 could order only two forks, or, on the contrary, order a greater number of forks. The barrel serves to control a sequence of gear shifts.

Depending on its rotational position, the barrel 100 will bring the stud 21 1 in different sections of the track 1 10. Two sections of the track 1 10 are visible in Figure 1. The section 1 1 1 is a section in a plane inclined relative to the axis of rotation of the cylinder 100, and the guide pin 21 1 in this section 1 10 in rotation imposes, by a cam effect (ramp effect) , a translation relative to the housing of the gearbox in a direction T parallel to the axis XX, the pin 21 1 and the fork that it controls. By cons, when, due to an additional rotation of the cylinder 100 about its axis, the pin 21 1 reaches the section 1 12 of the track 1 10, the latter being in a plane perpendicular to the axis of the barrel 100, the rotation of the latter no longer translates the pin 21 1 and the associated fork.

The stud 221 is guided by the track 120. Three sections 121, 122 and 123 of the track 120 are visible in Figure 1. The rotation of the barrel 100 brings successively the pin 221 in each of these sections of the track 120. The sections 121 and 123 being in two planes perpendicular to the axis of rotation of the cylinder 100, when the pin 221 is in one or the other of these sections, the rotation of the barrel 100 does not impose any translation movement. Conversely, the section 122 being in a plane inclined relative to the axis of rotation of the cylinder 100, by a camming effect, when the pin 221 is in the section 122, the rotation of the cylinder 100 causes a translation of the nipple 221. In Figure 2, a barrel 100 with two tracks is shown. It has also included the ranges it controls, and the pinions finally coupled to the shaft by the action of the control cylinder.

There is, as in Figure 1, a first track on the barrel 100, consisting of a section 1 1 1 inducing a cam effect and a section 1 12 does not induce camming effect. There is also a second track comprising a camming section 122 and a non-camming section 121. The pins 261 and 262 (or control sticks) are guided by the two tracks, respectively. They control forks 213 and 223, respectively via fork axes 212 and 222.

The fork axes 212 and 222 are elongated parts parallel to the axis X-X of rotation of the cylinder and on which are fixed at a distance from each other the corresponding nipple, and the corresponding fork beaks.

Each of the forks 213 and 223 comprises two nozzles whose ends are axial bearing faces for acting by a support in a direction parallel to the axis X-X on synchronization sleeves of a synchronizer 320, 420 respectively.

Synchronizers 320 and 420 have the function of coupling, or decoupling, gears 310, 31 1 or respectively 410, 41 1 defining gear ratios, with a secondary shaft 1000 of the gearbox.

The shaft 1000 of the gearbox is parallel to the axis X-X of rotation of the cylinder 100, and also to the axis of the fork 212, 222 respectively.

Thus, a rotational movement R of the barrel 100 around its axis of rotation XX causes, when a stud is engaged in a camming section of the corresponding track, a translation T of the corresponding fork, the actuation (or one of the two) synchronizer (s) that it controls and the engagement of a gear ratio. It is specified that the barrel 100 shown is able to control two forks and that the invention naturally applies to a cylinder that can control another number of ranges

The nipple 261 (or retractable control stick, or else blasting), acting in a direction perpendicular to the fork axis 212, has an end (its ball) which is inserted into the corresponding track of the cylinder 100 and maintained against it by a compression spring of the stud 261.

Thus, the stud 261 couples in motion the barrel 100 and the fork 213. In addition it maintains in position the fork 213 and its axis 212, by contact with the walls of the track of the barrel 100.

The spring of the stud 261 can be controlled so that the entire pin 261 disappears, uncoupling the barrel 100 and the fork 213, the movements of one then causing more movement of the other. To achieve this result, the ball is retracted, to no longer ensure contact with the barrel. The fork axis 222 carries, in the same way, a stud 262 which inserts its end into the corresponding track of the barrel 100 and couples in motion the barrel and the fork 223. The stud 262 also acts to maintain in position the fork 223 and its axis 222, by contact with the walls of the track of the barrel 100. The ball of the stud 262 can also be retracted, to no longer ensure contact with the barrel. The studs 261 and 262 are controlled respectively by control means 271 and 272 which can control the retraction (or erasure) of the corresponding shot.

Such a retraction causes the disengagement of the corresponding fork (or disconnection of the fork vis-à-vis the barrel) and the lack of transformation of any rotational movement of the barrel into a rotational movement of the range (the gear ratio controlled by the fork is thus not engaged or disengaged), as well as the absence of any friction between the barrel and the elements of the fork (its pin) stabilizing it.

The stud 261 is shown engaged in the corresponding track of the barrel, and the stud 262 is shown disengaged from the corresponding track. To stabilize the forks 213 and 223, the gearbox according to the invention further comprises stabilization systems 550 and 500 (or stabilization means), mounted to stabilize the sets of compounds on the one hand of the stud 261, of axis 212 and the fork 213, and secondly the stud 262, the axis 222 and the fork 223, when the billing 261 or 262 corresponding is retracted.

Such a stabilization system has the effect of reducing the possibilities of movement of the assembly formed by the stud 262, the axis 222 and the fork 223, including when the blasting 262 is retracted. It may include spring blasting.

In all cases, the stabilization system 500 is free in rotation vis-à-vis the cylinder, and acts for example by relying on the housing 520 of the gearbox or on an element attached to the housing 520 , or kinematically equivalent to the housing. The same comment applies to the stabilization system 550. A controlled stabilization system can be used, and it is then expected that it disappears when the fork 223 must be moved to engage the corresponding gear ratio. . Thus, the stabilization system 500 is coordinated with the rotation control of the cylinder 100 to stabilize the fork 223 when the latter is disengaged from the cylinder and not stabilize it when it is moved to engage a gear ratio. Thus, the stabilization system 500 is shown in the figure, applied to stabilize the range 223 because the blasting 262 is disengaged from the corresponding barrel track, and the stabilization system 550 is shown cleared (retracted) because the blasting 261 is engaged in the corresponding track.

In the context of a double clutch gearbox, having two secondary shafts 1000 and 1001, the forks may have the arrangement shown in Figure 3 around the cylinder 100, shown in a plane perpendicular to its axis. The pins 261, 262 and 263 are arranged in distinct angular sectors and distant from each other around the barrel. The forks 213 and 223, which are driven by the pins 261 and 262 act on free sprockets cooperating with the shaft 1000, while the fork 233, driven by the blasting 263 acts on free sprockets cooperating with the shaft 1001. The forks 213 and 223 are offset relative to one another angularly around the shaft 1000.

Other implementations of the forks on one or two secondary trees are compatible with the invention.

The nipples 261, 262 and 263 are retractable as has been presented in connection with Figure 2.

The cylinder 100 is rotated by a cylinder control motor 600, which comprises a sensor 610 for monitoring the angular displacement of the cylinder, which measures continuous way the angular displacement, and increment continuously, accordingly, the contents of a memory 910.

The barrel 100 carries on its circumference, in a given angular sector, a witness 700 for a sensor, for example for an optical sensor. The gearbox comprises, fixed relative to the housing of the box, an on-off sensor 800, for example an optical sensor, configured to detect the presence or passage of the indicator 700 in an angular position about the axis of rotation. XX of the cylinder 100. The sensor 800 is placed to locate a reference position θ ₀ of the cylinder 100 defined relative to the housing.

The gearbox further comprises a central unit 900 (or processor) to see if the sensor 800 indicates that the control cylinder 100 is at the angular position indicated by the control 700, and then initialize the tracking of the angular displacement of the cylinder 100 which is performed by the sensor 610 for monitoring the continuous angular displacement, by initializing the contents of the memory 910.

The central unit 900 is also configured to control, during initialization of the continuous angular tracking, a rotation of the barrel 100 to the observation that the barrel is at the angular position identified by the witness 700.

The central unit 900 is also configured to control the rotation of the barrel 100 to engage the gear ratios requested by the driver, once the rotation tracking initialized. In Figure 4, there is shown a method of implementation of the invention.

Typically, the invention must be implemented after the motor vehicle has been stopped, that the engine has for example been cut, and that the position of the barrel was lost by loss of the information contained in the memory 910. These events are presented as step 1. The driver wishing to restart and engage a gear ratio, the initialization of the rotational tracking of the barrel 100 is controlled. It is started by the disengagement of the forks 213, 223 and 233 vis-à-vis the barrel 100, during a step 2.

Then, during a step 3, the reference position θ ₀ identified by the sensor 800 is searched. The cylinder 100 is rotated by the engine 600 until the sensor 800 detects the marker 700 in front of it. During this movement, the sensor 610 measures the displacement and records the value of the angular displacement ΔΘ followed since the disengagement of the forks 213, 223 and 233 and the barrel 100.

In a preferred embodiment, it is implemented a dual detection of the position: step 3 is followed by a step 4 during which a reverse rotation is applied to the cylinder 100 by the engine 600. The sensor 800 detects again the marker 700 opposite it when passing in the opposite direction. In addition, a rotation of an angular displacement value for example -ΔΘ is applied to return to the location at which the forks and the barrel have been disengaged. The forks 213, 223 and 233 and the barrel 100 are then reengaged. The memory 910 is initialized on the basis of the two detections of the indicator 700 by the sensor 800.

The driver can then engage a gear ratio.

With the proposed process, the startup time is reduced, as well as the noise, the solicitation of the parts and the risk of failures commitment. The invention is not limited to the embodiment shown, but extends to all variants within the scope of the claims.

Claims

Gearbox for a motor vehicle comprising at least one coupling means (212, 213, 223, 233) for coupling a shaft (1000, 1001) to a pinion (310, 31 1, 410, 41 1) mounted around said shaft ( 1000, 1001), said coupling means (212, 213, 223, 233) being movable in translation, a control cylinder (100) rotatable to control the translation of said coupling means (212, 213, 223, 233). , a means (610, 910) for monitoring the angular displacement of the barrel (100), means (700, 800, 900) for determining whether the control barrel (100) is at a predetermined angular position (θ ₀ ) for initializing said tracking means (610, 910), and means (600, 900) for controlling a rotation of the barrel (100) until recognition that the barrel (100) is at said predetermined angular position (θ ₀ ) characterized in that the box further comprises means (261, 262, 263, 900) for disengaging the coupling means (212, 213, 223, 233) of the barrel (100) during the implementation of said means for controlling (600, 900) a rotation of the barrel (100) until the fact that the barrel (100) is at said predetermined angular position (θ ₀ ) and reengaging said coupling means (212, 213, 223, 233) in the barrel (100) to engage a gear ratio.

Gearbox according to claim 1, wherein the means (700, 800, 900) for determining whether the control cylinder (100) is at a predetermined angular position (θ ₀ ) comprises an on-off sensor (800) and a witness (700) placed on a section of the barrel (100), the on-off sensor (800) locating the witness (700).

Gearbox according to claim 1, further comprising an electric motor (600) for controlling the rotation of the barrel, the tracking means (610, 910) of the angular displacement of the barrel (100) comprising a tracking sensor (610) angular displacement of the barrel (100) placed in said electric motor (600) control.

Gearbox according to claim 1, wherein the means for controlling (600, 900) a rotation of the barrel until the observation that the barrel (100) is at said predetermined angular position (θ ₀ ) controls a rotation in one direction then in opposite direction to see twice the fact that barrel (100) is said predetermined angular position (θ ₀ ) so as to increase the accuracy of the finding.

Gearbox according to claim 1, wherein once it has been found that the barrel (100) is at said predetermined angular position (θ ₀ ), the box is configured to control the rotation of the barrel (100) to an initial position at which the coupling means (212, 213, 223, 233) is again engaged in the barrel (100).

Gearbox according to claim 1, wherein said means for disengaging (261, 262, 263, 900) the coupling means (212, 213, 223, 233) of the barrel (100) comprise retractable pins (261, 262, 263) to a interacting command, when they are not retracted, with a control track (1 10, 120, 130, 1 1 1, 1 12, 121, 122) present on the surface of the cylinder (100), and a unit control (900) to control their retraction prior to initialization or refitting after initialization.

A method of initializing an angular displacement tracking of a gearbox control cylinder for a motor vehicle, the box comprising at least one coupling means for coupling a shaft to a pinion mounted around said shaft, said coupling means being movable in translation, said barrel being rotatable to control the translation of said coupling means by means of a control track present on the surface of the barrel, characterized in that the method comprising a disengagement (2) of the means coupling the barrel followed by a control (3) in rotation of the barrel until the fact that the barrel is at a predetermined angular position, to initialize said tracking, and subsequently, a reengagement (4) of the coupling means in the barrel.

Computer program, which when implemented by a processor (900) leads to the implementation of the steps of the method according to claim 7.