FR2800805A1 - Automotive starter motor with axial stop for the drive pinion, has axially fixed washer between sliding pinion and motor bearing to prevent wear - Google Patents

Abstract

The starter motor output shaft (16) has a splined region (30) to guide and drive the sliding starter pinion. In the rest position the inner side of the pinion presses against the motor bearing (34), with a friction washer (32) between. The friction washer is fixed axially to the bearing to prevent the washer sliding along the shaft.

Description

The invention relates to a starter motor vehicle. The invention more particularly relates to a starter of the type comprising, axially aligned, a rear electric motor drives, via a gearbox, a front launcher, and type in which an output shaft of the gearbox comprises - a fluted front section externally which carries rotates a complementary rear portion of the launcher slidably mounted between a rear rest position in which bears axially on a bearing by means of a friction washer, and a front driving position; and a smooth rear section which guides the reducer output shaft in rotation in a ring of the bearing.

During operation of the starter, after driving the crown of the combustion engine, the launcher returns to the rear position. When it comes into contact with the front face of the bearing it is always animated by a rotation movement <B> due to the inertia of the device. The friction between the two parts causes a significant wear which can cause a malfunction of the system.

The French patent application 99-09978 discloses a starter in which a washer is interposed between the rear free end of the launcher and the front face of the bearing. Thus, the launcher rubs the washer until it stops completely, the pressure and contact speed are reduced, as well as the risk of deterioration of the bearing.

However, when the thrower is in the forward position, washer is free in translation and rotation. It is also subjected to vibrations caused by the starter, it can then fall into the groove of the grooves and thus hinder the return launcher back rest position.

In addition, the irregularities of the friction between the transverse faces of the washer and the front face of the bearing and the rear face of the launcher and generates noise and increases the wear of the parts concerned.

In order to provide a solution to these drawbacks, the invention proposes a starter of the type described above, characterized in that the friction washer is fixed axially to the bearing. According to other features of the invention - the friction washer is rotatably connected to the bearing; the friction washer is fixed to the bearing by crimping; the bearing is overmolded around the friction washer; - The friction washer has fingerprints at its outer periphery; - friction washer has fingerprints at least one of transverse faces; the periphery of the friction ring is not circular, and the housing of the bearing which receives it has a shape complementary to that of the periphery of the friction washer; - The friction ring has resilient claws on its outer periphery, and it is mounted tight radially in a housing of the bearing; - The friction washer has a treatment or a coating on its transverse support surface for the launcher.

Other features and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference will be made to the appended figures in which - Figure 1 is a partial longitudinal sectional view of a motor starter according to the state of the art; - Figure 2 shows the assembly by crimping bearing and a friction washer according to the invention; - Figure 2A is a detail view of Figure 2 on a large scale, the crimping of the friction washer on the bearing; - Figure 3 is a perspective view of a friction washer which has notches at its periphery; - Figure 4 shows a friction washer which has axial through holes; - Figure 5 shows a friction washer which has imprints on one of its transverse faces; FIG. 6 represents a corrugated friction washer; In the rest of the description, a forward-to-back orientation will be used, without limitation.

It corresponds to the orientation from left to right in accordance with FIGS. 1 and 2. FIG. 1 represents a starter 10 of a motor vehicle according to the state of the art.

It comprises an electric motor which drives an armature shaft 14 and a gear output shaft 16.

An axial bore 18 is formed in a rear free end 20 of the gear output shaft 16. It opens into the rear radial face of the rear free end 20 of the output shaft 16 and is blind at its other end. before.

The axial stalling of the gear output shaft 16 from the rear to the front is effected by a flange 22 which is fixed on the rear end section of the output gear shaft 16 by a method such that laser welding, electron bombardment, plasma torch welding, bonding or shrinking.

The axial stalling of the output shaft 16 from the front to the rear is achieved by a ball disposed at the bottom hole 18 of the rear free end 20 of the output shaft of gearbox 16. When a force is exerted from the front to the rear on the gear output shaft 16, the ball is in contact on the one hand with the front free end 24 of the armature shaft 14 and, on the other hand, with the blind bottom of the piercing 18.

The armature shaft 14 carries a pinion 26 of an epicyclic gearbox which transmits the rotational movement to the output shaft 16. A front thrower 28 slides axially on a splined front section 30 of the output shaft gearbox 16, which thus constitutes the launcher shaft, between a position before meshing and a rear rest position.

In the rest position, the front thrower 28 bears axially on a friction washer 32, interposed between the front thrower 28 and the bearing 34. It makes it possible to limit the wear of the bearing 34.

A radial clearance groove 36 separates the fluted front section 30 and a smooth rear section 38.

The smooth rear section 38 of the rear free end 20 of the output shaft 16 is guided in rotation in the ring 40 mounted in the housing of the fixed bearing 34.

The epicyclic gear reducer comprises a set of satellites whose axis of rotation is carried the flange 22 of transverse orientation. The satellites are immobilized axially in translation by a plate force-fitted on the axes of the satellites. This translation retention can also be achieved by satellite axes screwed into the flange 22 and each having a head.

The gearbox thus comprises a crown 42 with internal teeth which is fixed, in the assembly shown, by overmolding in a transverse plate 44 fixed to the casing 46 of the starter.

The splined forward section 30 of the gear output shaft 16 has outer splines which cooperate with internal splines formed in the inner axial hole of the front thrower 28. When the forward thrower 28 is in the meshing position, the outer splines cooperate with the internal splines to transmit the torque from the gear output shaft 16 to the front thrower 28.

When the launcher 28 returns from its position before meshing, in which it rotates the crown of the combustion engine to start, in its rear rest position, it comes into contact with the fixed friction washer 32. It is the friction on the friction washer 32 which slows down the rotational movement due to the inertia of the parts of the launcher 28.

According to the invention, the friction washer 32 is fixed axially to the bearing 34, which makes it possible to eliminate the risk of displacement of the friction washer 32 towards the rear of the reducing output shaft and its sliding in the radial groove release and increase the comfort of use of the starter 10, as well as its reliability.

Indeed, when the friction washer 32 falls into the radial clearance groove 36 and upon return of the launcher to its rear rest position, the forces exerted by the latter friction washer 32 are poorly distributed, causing wear fast of the elements concerned and in particular of the rear transverse contact face of the launcher 28, the machining of the radial clearance groove 36 and the friction washer 32.

In addition, in some cases, the displacement of the friction washer 32 on the gearbox output shaft 16 can prevent the launcher return 28 in its rear rest position, such that the front portion remains in mesh with the engine crown. with combustion. In this case, it is the combustion engine of the vehicle that will drive the electric motor 12 via the launcher 28 and the gear output shaft 16 which will cause in a first time, following the overspeed pinion, a deterioration of the launcher 28 by heating and seizing parts friction. In a second step, the free wheel of the launcher 28 deteriorated no longer protects the electric motor 12 and its reducer against overspeed, which causes the destruction of the latter by centrifugal and thermal effects.

Advantageously, the friction washer 32 is rotatably connected to the bearing 34. Thus, when the launcher 28 is in the position before meshing, this arrangement makes it possible to eliminate the noise caused by the vibration of the friction washer 32.

Advantageously, the front transverse face of the friction washer 32 is covered with a coating or a treatment improves its characteristics of friction or wear resistance so as to increase the service life of the friction washer 32 or to reduce the dimensions for an equivalent service life. When the coating or the treatment increases the coefficient of friction between the friction washer 32 and the rear radial face of the launcher 28, the launcher's rotational stopping time is reduced, which reduces the noise and vibration nuisances of the starter 10.

In a first embodiment, the bearing 34 is overmolded on the washer. In a second embodiment the friction washer is attached to the bearing 34. The fixing of these two elements can be achieved by known methods such as welding, gluing, scratching, crimping hot or cold ...

The bearing 34 is then slightly modified. The housing of the bearing 34 is stepped in accordance with FIG. 2. It comprises a first rear section 50 whose diameter corresponds to the outer diameter of the ring 40, and a second front section 52 whose diameter is greater than that of the first rear section 50 and is greater than the outside diameter of the friction washer 32.

The two sections 50 and 52 are delimited by a transverse front shoulder which constitutes an annular transverse bearing surface which makes it possible to position the friction washer in translation in the longitudinal direction from front to rear. In the case of crimping, according to Figure 2, the friction washer 32 is placed in the second front section 52 of the bearing bearing against the shoulder 54, and is crimped.

A lip of reprocessed material 56 makes it possible, on the one hand, to lock the friction washer 32 in translation towards the front and, on the other hand, to lock in rotation by the application of a clamping stress in the direction of the transverse face. annular support 54.

Indeed, the material lip 56 clamps the friction washer on an annular surface 58, according to Figure 2A, whose width corresponds for example to half the difference between outer diameter D1 of the friction washer 32 and the inner diameter of the material lip 56. In order to optimize the locking in rotation of the friction washer 32, in both modes of attachment, it is advantageous to use a friction washer 32 having particular shapes.

In a first variant, according to FIG. 3, the friction washer 32 has notches 60 at its periphery. radial height of the notches is less than the width L of the annular surface shown in phantom in FIG. 3. Thus, during crimping the friction washer 32 or over molding of the bearing the material lip 56, or the material of the bearing 34 respectively, penetrates into notches and blocks the friction washer 32 in rotation. In a second variant, according to FIG. 4, the friction washer 32 has axial through holes 62. The holes are located in the annular surface 58, represented by dotted lines in FIG. 4. Thus, during crimping or overmoulding, the lip of material 56, or the material of the bearing respectively, penetrates the holes so as to lock in rotation with friction washer 32.

In a third variant, in accordance with FIG. 5, friction washer 32 has indentations 64 on its front transverse face 55. The indentations are the annular surface represented by dashed lines in FIG. 5. Thus, during crimping or over-molding of the Bearing 34, the material lip 56 or the material of the bearing 34 respectively, matches and blocks the rotation of the friction washer 32. In a fourth variant, according to Figure 6, the friction washer 32 comprises radial corrugations 66. Thus, during crimping or overmoulding of the bearing 34, the material lip 56, or the material of the bearing 34 respectively, adapts to the profile of the washer 32 and blocks the friction washer in rotation. A friction washer 32 according to the invention. a previous variant does not require angular indexing relative to the bearing 34. This allows a simple and fast assembly of these two elements 32 and 34. D In a variant not shown, the periphery of the friction washer is not circular of revolution, and it oval example. It puts in position in the bearing 34 whose housing has a shape complementary to that of its periphery. Thus, the material lip 56 then serves for its sole function the stopping in axial translation towards the front of the friction washer 32, the rotational locking of the washer 32 being obtained by the cooperation of the complementary non-circular forms of the friction washer 32 and from landing 34.

In another alternative embodiment, not shown, the friction washer 32 is a metal washer having at its outer periphery resilient claws. The friction washer 32 is then mounted tight radially in the bearing 34 so that the resilient claws are embedded in the housing of the bearing 34 thus blocking the friction washer 32 in rotation and in translation.

The invention makes it easier to assemble the components of the starter 10, and in particular of the gearbox output shaft 16, the launcher 28 and the ring 40 because the friction washer 32 is pre-assembled on the bearing 34. reduces the production costs of the starter 10.

Claims (9)

<U> CLAIMS </ U> 1. Starter of the type comprising, axially aligned, a rear electric motor (12) which drives, via a gearbox, a front launcher (28), and of the type in which an output shaft of the gearbox (16) comprises - an externally splined front section (30) which carries and rotates a complementary rear portion of the launcher (28) which is slidably mounted between a rear rest position in which it bears axially on a bearing (34) by the intermediate of a friction washer (32), and a front driving position; and - a smooth rear section (38) which guides the output shaft of the gearbox (16) in rotation in a ring (40) of the bearing (34), characterized in that the friction washer (32) is fixed axially to the bearing (34). 2. Starter according to the preceding claim, characterized in that the friction washer (32) is rotatably connected to the bearing (34). 3. Starter according to any preceding claim, characterized in that the friction washer (32) is fixed to the bearing (34) by crimping. 4. Starter according to one of claims or 2, characterized in that the bearing (34) is overmolded around the friction washer (32). 5. Starter according to any preceding claim, characterized in that the friction washer (32) has indentations (60) at its outer periphery. 6. Starter according to any preceding claim, characterized in that the friction washer (32) has indentations (62, 64, 66) on at least one of its transverse faces. 7. Starter according to any preceding claim, characterized in that the periphery of the friction washer (32) is not circular, and in that the housing of the bearing (34) which receives it has a shape complementary to that the periphery of the friction washer (32). 8. Starter according to claim 1, characterized in that the friction washer (32) comprises resilient claws on its outer periphery, and in that it is mounted tight radially in a housing of the bearing (34). 9. Starter according to any one of the preceding claims, characterized in that the friction washer (32) comprises a treatment or coating on its transverse support surface for the launcher (28).