WO2015155473A1

WO2015155473A1 - Starter assembly for a heat engine

Info

Publication number: WO2015155473A1
Application number: PCT/FR2015/050914
Authority: WO
Inventors: Guillaume Seillier; Benoît BALEYDIER; Gauthier VIGY
Original assignee: Valeo Equipements Electriques Moteur
Priority date: 2014-04-11
Filing date: 2015-04-08
Publication date: 2015-10-15
Also published as: CN106164467A; FR3019858B1; CN106164467B; FR3019858A1; EP3129639A1

Abstract

A starter assembly (1) for a heat engine, including: a drive shaft (7) including an annular groove (53); a bushing (15) mounted so as to be translatably movable relative to the drive shaft (7); a pinion (17) mounted on the bushing (15); an element (25) for stopping the bushing (15), which is mounted in the annular groove (53) of the drive shaft (7), the stopping element (25) being a resilient circular part which is radially expandable and which consists of an at least 360° metal winding, the inner diameter of which falls between the diameter of the annular groove (53) and the diameter of the drive shaft (7). The dimensions of the stopping element (25) can also be such that the stopping element is rotationally connected to the drive shaft.

Description

STARTER ASSEMBLY FOR THERMAL ENGINE

The present invention relates to the field of starters for combustion engines, especially for motor vehicles.

In the state of the art, the starters generally comprise an electric motor for rotating a sprocket launcher via a coupling device. The launcher is movable in translation relative to the drive shaft and is controlled by a switch via a fork, which allows the translational movement of the pinion to engage a complementary sprocket gear, also called crown, associated to the engine. However, in order to ensure the correct operation of the starter a stop must be provided on the drive shaft especially when the coupling device comprises a clutch, the pinion coming against the stop when the launcher is moved by the fork, which allows coupling between the electric motor and the launcher. This stop is for example made by a rod disposed in an annular groove of the drive shaft supporting the launcher and a stop ring disposed around the rod.

The pinion can be mounted on the shaft so that it is free to rotate relative to the drive shaft, in particular when the pinion is decoupled from the shaft, for example by means of a coupling means .

With such a gear, it is created over time a wear between the ring, the thrust ring and the drive shaft so that a large game can appear that can lead to malfunctions of the coupling device, the clutch can no longer be compressed to transmit the torque to the launcher. More particularly, the ring undergoes significant wear which does not meet the new endurance demands for this type of machines.

In a variant, the pinion may be integral in rotation with respect to the drive shaft, in particular when it abuts against the stop ring. More specifically, the pinion is movable in translation through a helical connection with the drive shaft. During this translation movement, namely when the pinion is at a distance from the stop ring, this helical connection can apply to the pinion, a rotational movement relative to the drive shaft. When the pinion is engrained in a ring of the heat engine and abuts against the stop ring, the drive shaft then rotates the pinion which is then integral in rotation with the drive shaft.

With such a pinion, it is created over time a wear of the ring due to the rotation of the ring around the shaft, especially when the shaft rotates and the pinion is at a distance from the stop.

In addition, whatever the configuration of the pinion, such an abutment implements several parts which complicates the manufacture of the machine.

It therefore appears necessary to solve the aforementioned drawbacks of the state of the art and in particular to reduce or avoid the displacement of the stop due to wear of the parts forming the abutment. It appears more particularly necessary to avoid premature wear of the ring.

The object of the present invention is therefore to provide a starter assembly in which the wear of the stop stop of the pinion launcher is reduced and allows the proper operation of the coupling device between the drive shaft and the launcher even after a significant number of startup cycles.

The present invention therefore relates to a starter assembly for a heat engine comprising:

a drive shaft comprising an annular groove,

- A bushing, in particular a pinion body, mounted movable in translation relative to the drive shaft,

- a pinion mounted on the socket,

a stop element of the bushing mounted in the annular groove of the drive shaft;

wherein the stop member is a radially expandable resilient circular member formed by a metal winding of at least 360 °, the inside diameter of which is between the diameter of the annular groove and the diameter of the drive shaft.

Such a stop element may be configured to be secured in rotation relative to the shaft.

Such a stop element makes it possible to be mainly used via the contact surface between the stop element and the bushing and / or the pinion, when the bushing and / or the pinion is rotated relative to the shaft. The stop member thus has a predetermined wear zone.

According to another aspect of the invention, the stop element is mounted diametrically tight on the groove of the shaft: clamping between 0.05 mm and 0.45 mm. This allows the stop member to rotate with the drive shaft. Thus there is no risk of wear.

According to another aspect of the present invention, the stop member has a substantially uniform thickness.

According to a further aspect of the present invention, the axial clearance between the stop member and the groove is between 0.1 and 0.3 mm, the thickness of the stop member being less than the width of the annular groove. This allows for easy editing and a game reduced enough not to affect the kinematics of the launcher.

According to an additional aspect of the present invention, the metal winding forms an axially extending helix.

According to another aspect of the present invention, the stop member comprises a first portion of uniform thickness slightly less than 360 °, a second portion of uniform thickness slightly less than 360 ° superimposed on the first portion and an intermediate portion. connection between the first and the second part, said intermediate portion extending obliquely between one end of the first part and one end of the second part.

According to a further aspect of the present invention, the outer diameter of the stop member corresponds to plus or minus 0.5mm to the outside diameter of the end of the bushing coming into contact with the stop member. This allows for a maximum contact area while optimizing the weight of the starter.

According to an additional aspect of the present invention, the annular groove is located between 5 mm and 8 mm of a guide bearing of the drive shaft. This reduces the length of the starter while having no risk of friction between the bearing and the stop element. According to a first variant of the present invention, the pinion can be integral in rotation relative to the drive shaft, in particular when the pinion is in abutment against the stop element.

According to a second variant, the pinion may be free to rotate with respect to the drive shaft, in particular when the pinion is uncoupled from the drive shaft, for example by means of a coupling means.

According to any one of the first and second variants above, the pinion can be integral in translation relative to the sleeve. In particular, the pinion and the socket may be a single piece.

According to any one of the first and second variants above, the pinion may also be movable in translation relative to the sleeve. The pinion is mounted on a portion of the sleeve, which is mounted on the drive shaft. In particular a spring may be provided between the pinion and a shoulder of the sleeve. In this case, it is the bushing which abuts against the stop element. In addition, the bushing may comprise a stop having a shape identical to that of the stop element to allow the pinion to abut on the bushing.

The present invention further relates to a starter assembly for a heat engine comprising:

a drive shaft comprising an annular groove,

a pinion mounted to move in translation relative to the drive shaft,

- A pinion stop member mounted in the annular groove of the drive shaft, the stop member being configured to be integral in rotation relative to the drive shaft.

The stop member may be a radially expandable elastically resilient circular piece formed by a metal winding of at least 360 °, the inside diameter of which is between the diameter of the annular groove and the diameter of the drive shaft.

The previously described features may be applied alone or in combination with this invention.

The present invention also relates to a starter comprising a previously described assembly. In another aspect of the present invention, the bushing is rotatably coupled to the drive shaft via a clutch system.

The present invention also relates to a method of mounting a stop member of a starter assembly for a heat engine on a drive shaft comprising an annular groove, characterized in that the stop member is formed by a part. radially expandable elastic ring formed by a metal winding of at least 360 ° whose inner diameter is between the diameter of the annular groove and the diameter of the drive shaft, the method comprising the following steps:

a mounting element is used comprising a first thin tubular portion whose inside diameter is slightly greater than the outside diameter of the drive shaft and a conical portion whose smaller diameter is smaller than the diameter of the annular groove,

the mounting element is placed on the drive shaft so that the end of the tubular portion reaches the annular groove,

the stop member is placed around the conical portion of the mounting member, the stop member is pushed along the mounting member to the annular groove.

Other features and advantages of the invention will appear in the description which will now be made, with reference to the accompanying drawings which show, by way of indication but not limitation, possible embodiments.

On these drawings:

- Figure 1 shows a sectional view of a starter according to one embodiment of the present invention;

FIG. 2 is a diagram of the front portion of a drive shaft according to an embodiment of the present invention;

FIG. 3 represents a diagram of a stop element according to a first embodiment of the present invention;

FIG. 4 represents a diagram of a stop element according to a second embodiment of the present invention;

FIG. 5 represents a diagram of the steps for mounting the stop element on the shaft training;

- Figure 6 shows a diagram of a mounting member of the stop member on the drive shaft;

- Figure 7 shows a diagram of the mounting member of the stop member and the drive shaft;

- Figure 8 shows a diagram of the mounting element placed on the drive shaft;

- Figure 9 shows a diagram of the mounting of the stop member on the drive shaft via the mounting member;

In these figures, the same reference numbers designate identical elements.

FIG. 1 shows a starter 1 comprising a housing 3 inside which an electric motor 5 is arranged to rotate a drive shaft 7 about an axis X. The drive shaft 7 comprises a part rear 7a linked to the electric motor 5 and a front portion 7b rotatably coupled to the rear portion 7a. However, a drive shaft 7 made in one part is also conceivable within the scope of the present invention. The rear portion 7a of the drive shaft 7 is mounted on guide bearings 9a and 9b and the front portion 7b is mounted on guide bearings 9c and 9d.

Launcher

A driver 8 is movably mounted in translation on the front portion 7b of the drive shaft 7, the driver 8 being rotatably coupled to the drive shaft 7. A sleeve 15, also called pinion carrier, mounted movable in translation on the front portion 7b of the drive shaft 7 is coupled in rotation to the driver 8 via coupling means 13 such as a clutch system in the case of Figure 1 or a wheel system free. The clutch system comprises a first plurality (two in this case) of rings 131 linked to the driver 8 intermingled with a second plurality (three in this case) of rings 132 connected to the bushing 15 so that the compression rings 131 and 132 against each other creates a coupling between the driver 8 and the bushing 15. A pinion 17 is slidably mounted on the bushing 15 and held on the bushing 15 by a stop element 22 such as a circlip or a radially expandable resilient circular piece formed by a metal winding of at least 360 °. The pinion 17 is forced against the stop element 22 by a helical spring 19, possibly frustoconical, placed between the bushing 15 and the pinion 17. The assembly comprising the bushing 15, the pinion 17, the coupling means 13, the driver 8 and the associated elements such as the coil spring 19 form a launcher 21 movable in translation relative to the drive shaft 7 between a rest position where the launcher 21 comes against a rear stop 23 as shown in FIG. 1 and an active position in which the launcher 21 comes into contact with a stop member 25 mounted on the front portion 7b of the drive shaft 7. The axial displacement of the launcher 21 is controlled by a fork 27 connected to a contactor 29.

contactor

The contactor 29 comprises a set of coils 33 surrounding a tubular chamber 35 enclosing a magnetic core 31. The set of coils 33 comprises a call coil 33a and a holding coil 33b. The magnetic core 31 comprises a movable portion 31a mounted to move in translation in the tubular chamber 35 and a fixed portion 31b. The movable portion 31a comprises a central portion 310, also called the hitch pin, connected to the fork 27 and a peripheral portion 311, the two parts 310 and 311 being separated by a helical spring 312 and being axially movable relative to one another. to the other along a Y axis between a rest position shown in Figure 1 where the helical spring 312 is not compressed and a position in which the coil spring 312 is compressed. The fixed portion 31b of the magnetic core 31 comprises an axial hole along the Y axis in which is inserted a rod 37 movable axially. The rod 37 passes through the fixed portion 31b of the magnetic core 31 and protrudes firstly into the tubular chamber 35 and secondly into a contact chamber 39 defined by a cover 41. A contact plate 45 located in the chamber contact plate 39 is fixed to the rod 37 and extends perpendicularly to the rod 37. Two contact terminals 47 and 49 are arranged in the contact chamber 39 facing the contact plate 45. These contact terminals 47 and 49 are connected to the electric motor and are configured to start the electric motor 5 when they are are connected to each other. One 47 is for example connected to the + terminal of a battery while the other 49 is connected to the electric motor 5. A coil spring 43 is placed between the cover 41 and the rod 37 so as to constrain the rod 37 in a rest position in which the contact plate 45 is in contact with the fixed part 3 lb of the magnetic core 31.

General operation of the starter

Thus, in operation, under the action of the set of coils 33, the mobile part 31a of the magnetic core 31 is moved from its rest position in which it is in contact with an abutment 51 towards the fixed part 31b of the magnetic core 31 until the two parts 31a and 31b are in contact. The call coil 33a is then no longer powered and only the holding coil 33b maintains the position of the movable portion 31a against the fixed portion 31b. The displacement of the movable portion 31a of the magnetic core 31 causes on the one hand the displacement of the rod 37 and the contact plate 45 to an active position in which the contact plate 45 comes into contact with the contact terminals 47 and 49 which has the effect of actuating the electric motor 5 and secondly the movement of the fork 27 which causes the passage of the launcher 21 from its rest position to its active position.

During the movement of the launcher 21 towards its active position, the pinion 17 comes to mesh with a ring gear 30 (shown schematically) of the engine (not shown) to be started, and then the launcher 21 abuts the stop element 25. , the pinion 17 does not mesh directly with the ring gear 30 but comes against the tooth with the ring gear 30, which causes the helical spring 312 of the contactor 29 to be compressed. Then, when the electric motor 5 is launched, the rotation is transmitted to the launcher 21 (the compression of the coil spring 312 for compressing the clutch system rings of the coupling means 13) which then meshes with the ring gear 30 and abuts the stop element 25. In this position, the spring helical 312, is only slightly compressed to provide a negative abutment and allow the coupling means 13 to engage to transmit the rotational movement of the drive shaft. 7 to the launcher 21 and allow the pinion 17 to drive the ring 30 in rotation. Once the heat engine (not shown) is launched, the coupling means 13 decouples the bushing 15 and the pinion 17 of the driver 8, and the pinion is disengaged from the ring 30 so that the electric motor 5 can be stopped. However, between the time of launch of the engine (not shown) and the decoupling between the bushing 15 and the driver 8, the pinion 8 can be driven at a speed of rotation greater than the speed of the drive shaft 7 by the ring gear 30 while being held against the stop element 25, it is then said that the pinion 17 is over-speed with respect to the drive shaft 7 and to the stop element 25 which is connected to the drive shaft 7. There is then friction that is created between the pinion 17 and the stop element 25. These friction and the axial force applied by the pinion 17 on the stop member 25 driving with the stop elements of the state of the art to the formation of a clearance between the drive shaft 7 and the stop element which can lead to the malfunction of the coupling means 13 due to the displacement of the stop which creates a play against positive stop that prevents the proper functioning of the clutch of the casting means 13. The structure of the stop member 25 of the present invention therefore aims to solve this problem.

Drive shaft and stop element

FIG. 2 shows an exemplary embodiment of the front portion 7b of the drive shaft 7. The front portion 7b comprises a first portion 701 connecting with the rear portion 7a of the drive shaft 7 and the contact with the bearing 9c, a second part 702 comprising helical splines on which is mounted the driver 8 and which facilitate the gear of the pinion 17 on the ring 30 when the electric motor 5 rotates faster than the engine and the gearing of the pinion 17 of the ring 30 when the engine is running faster than the electric motor 5, a third portion 703 on which is mounted the sleeve 15, an annular groove 53 and a fourth portion 704 ensuring contact with the bearing 9d. The annular groove 53 is located near the fourth portion 704 and therefore close to the bearing 9d, for example less than 1 cm from the bearing 9d. The stop element 25 is mounted in the annular groove 53 of the front portion 7b of the drive shaft 7. In addition, so as to minimize the wear generated by the different starting cycles in which the launcher 21 abuts on the stop element 25, the latter is formed by a metal winding, for example steel, at least 360 ° whose inner diameter is between the inner diameter of the annular groove 53 and the outer diameter of the drive shaft 7 adjacent to the annular groove 53. The stop element 25 is therefore an elastic circular piece radially expandable so as to be positioned in the annular groove 53 during assembly which will be described in more detail in the following description. Preferably, the stop element 25 is mounted tightly in the annular groove 53 so as to create a surface support between the stop element 25 and the drive shaft 7 and thus reduce the wear created by the friction with the pinion 17. In addition, the stop element 25 has a substantially uniform thickness corresponding to 1 mm near the width of the annular groove 53 while being less than the width of the annular groove 53 so that the stop member 25 can be inserted into the annular groove 53 while minimizing the axial clearance between the stop member 25 and the drive shaft 7.

According to a first embodiment shown in FIG. 3, the metal winding of the stop element 25 forms an axially extending helix whose different turns or turns are in contact with one another so that the winding can not be compressed axially as a coil spring. The section of the winding can be varied so as to obtain a constant thickness for the stop member 15. The number of turns of the winding can vary. Preferably, the winding comprises two turns which allows radial deformation without applying too great a force while allowing sufficient clamping in the annular groove 53.

According to a second embodiment shown in FIG. 4, the metal winding of the stop element 25 comprises a first portion 251 of uniform thickness on a periphery slightly less than 360 °, a second portion 252 of uniform thickness. circumferentially slightly smaller than 360 ° superimposed on the first portion 251 and an intermediate portion 253 connecting the first 251 and the second portion 252, said intermediate portion 253 extending obliquely between an end of the first portion 251 and a end of the second part 252. The angle between the intermediate portion 253 and the other two parts 251 and 252 is between 20 and 70 °. In addition, a greater number of parts can be envisaged. In this case, a second intermediate portion 253 is added to the free end of the second portion 252 and a third portion similar to the first 251 and second 252 portions is added. However, as for the previous embodiment, a winding comprising two turns seems satisfactory.

Method of mounting the stop member on the drive shaft

The various steps of mounting the stop member 25 on the drive shaft 7 will now be described in detail from FIG.

The first step 101 concerns the use of a mounting element 55 shown in FIG. 6. The mounting element 55 comprises a tubular portion 55a whose internal diameter is slightly greater than the outside diameter of the fourth portion 704 of the portion before 7b of the drive shaft 7 and a conical portion 55b whose smaller diameter is smaller than the diameter of the annular groove 53 and the inside diameter of the stop member 25.

The second step 102 relates to the placement of the mounting member 55 on the end of the front portion 7b of the drive shaft 7, the mounting member 55 is threaded around the fourth portion 704 as shown by the arrow 57 in Figure 7 to be positioned so that its end is adjacent to the annular groove 53 as shown in Figure 8. For this, the size of the mounting member 55 can be determined so that that the end of the mounting member 55 is adjacent the annular groove 53 when the mounting member 25 abuts the end of the front portion 7b of the drive shaft 7.

The third step 103 relates to the placement of the stop member 25 on the end of the mounting member 55 as shown in FIG. 9.

The fourth step 104 consists in axially pushing the stop element 25 along the mounting element as indicated by the arrow 59 in FIG. 9. Due to the conical shape of the mounting element 55, the stop member 25 will deform radially under axial pressure. Once the stop member 25 at the end of the mounting member 55, additional axial pressure slides the stop member 25 at the annular groove 53 so that stop 25 retracts radially into the annular groove 53. The element stop 25 is then positioned in the annular groove 53.

Thus, the use of a stop element 25 formed by a resilient and radially expandable circular metal winding which is positioned in an annular groove 53 of the drive shaft 7 maximizes the surfaces in contact when the pinion 17 abuts on the stop element 25 and thus reduces the wear of the stop element 25 during the starting cycles so as to allow the negative backstop clearance required for the proper operation of the system to In addition, the stop element 25 according to the present invention allows easy handling and simple assembly in particular because it consists of a single piece. Furthermore, this stop element 25 can be used with all coupling systems, such as freewheel systems. Indeed, in the latter, it is not necessary to have a negative abutment play, however, the presence of a stop member 25 is necessary to prevent the pinion 17 comes into contact with the housing 3 or 9d bearing or other starter elements 1.

Such a stop element 25 as described above can be mounted on the drive shaft of a fixed freewheel starter, as described in application FR 2 908 161 filed by DENSO CORPORATION on 2 November 2007 replacing the assembly consisting of a ring and an abutment ring, as visible in Figures 1 and 6.

Such a stop element 25 as described above can also be mounted on the drive shaft of a fixed freewheel starter, as described in the application FR 2 993 014 filed by ROBERT BOSCH GMBH on July 9, 2013. In this case, the stop element is disposed inside the pinion and around the drive shaft instead of the assembly consisting of a ring and an abutment ring such that visible in Figures 2, 6 and 7.

Claims

A starter assembly (1) for a heat engine comprising:

a drive shaft (7) comprising an annular groove (53),

a bushing (15) mounted to move in translation relative to the drive shaft (V),

a pinion (17) mounted on the sleeve (15),

a stop element (25) of the bushing (15) mounted in the annular groove (53) of the drive shaft (7),

characterized in that the stop member (25) is a radially expandable elastically resilient circular member formed by a metal winding of at least 360 °, the inside diameter of which is between the diameter of the annular groove (53) and the diameter of the drive shaft (7).

2. The assembly of claim 1 wherein the stop member (25) has a substantially uniform thickness.

3. The assembly of claim 2 wherein the axial clearance between the stop member and the groove is between 0.1 and 0.3 mm, the thickness of the stop member being less than the width of the annular groove.

4. An assembly according to one of the preceding claims wherein the metal winding forms an axially extending helix.

5. An assembly according to one of claims 1 to 3 wherein the stop element (25) comprises a first portion (251) of uniform thickness slightly less than 360 °, a second portion (252) of uniform thickness. slightly lower than 360 ° superimposed on the first portion and an intermediate portion (253) connecting the first (251) and the second (252) portion, said intermediate portion (253) extending obliquely between one end of the first portion (251) and an end of the second portion (252).

6. Assembly according to one of the preceding claims wherein the outer diameter of the stop element (25) corresponds to plus or minus 0.5mm to the outside diameter of the end of the sleeve (15) coming into contact with the 'element stop (25).

7. An assembly according to one of the preceding claims wherein the annular groove (53) is located between 5mm and 8mm of a guide bearing (9d) of the drive shaft (7).

8. Assembly according to one of the preceding claims wherein the pinion (17) is integral in rotation relative to the drive shaft (7).

9. Assembly according to one of the preceding claims, the pinion (17) and the sleeve (17) forming a single piece.

10. An assembly according to any one of claims 1 to 7, wherein the pinion (17) is free to rotate relative to the drive shaft (7).

A starter assembly (1) for a heat engine comprising:

a drive shaft (7) comprising an annular groove (53),

a pinion (17) mounted to move in translation relative to the drive shaft (V),

- a stop element (25) of the pinion (17) mounted in the annular groove (53) of the drive shaft (7),

characterized in that the stop element (25) is configured to be rotatably connected to the drive shaft (7).

12. The assembly of claim 11, the stop element (25) being a radially expandable elastically elastic piece formed by a metal winding of at least 360 ° whose inner diameter is between the diameter of the annular groove (53). ) and the diameter of the drive shaft (7).

13. Starter (1) comprising an assembly according to one of the preceding claims.

14. Starter (1) according to the preceding claim wherein the sleeve (15) is rotatably coupled to the drive shaft (7) via a clutch system.

15. A method of mounting a stop member (25) of a starter assembly (1) for a heat engine on a drive shaft (7) comprising an annular groove (53) characterized in that the element stopper (25) is formed by a radially expandable elastically resilient circular member formed by a metal winding from minus 360 ° whose inside diameter is between the diameter of the annular groove (53) and the diameter of the drive shaft (7), the method comprising the following steps:

a mounting element (55) is used, comprising a first thin tubular portion (55 a) whose inside diameter is slightly greater than the outside diameter of the drive shaft (7) and a conical portion (55b) whose most small diameter is smaller than the diameter of the annular groove (53),

the mounting element (55) is placed on the drive shaft (7) so that the end of the tubular part (55a) reaches the annular groove (53), the element stopping (25) around the conical portion (55b) of the mounting member (55),

the stop member (25) is pushed along the mounting member (55) to the annular groove (53).