EP2769082A2

EP2769082A2 - Starter for combustion engine

Info

Publication number: EP2769082A2
Application number: EP12780245.2A
Authority: EP
Inventors: Christian Mornieux
Original assignee: Valeo Equipements Electriques Moteur SAS
Current assignee: Valeo Electrification
Priority date: 2011-10-14
Filing date: 2012-10-12
Publication date: 2014-08-27
Also published as: WO2013054055A3; FR2981412B1; CN103930668B; WO2013054055A2; CN103930668A; FR2981412A1

Abstract

The invention relates to a starter head for an internal combustion engine, including a casing which defines a reduction chamber and which includes a surface for mounting an electric motor M including a drive pinion, a reduction gear which is arranged in the reduction chamber and which includes an epicyclic gear train including planetary gears, which are to be rotated by the drive pinion of the electric motor, and an outer ring which has an axis Δ and which is connected to the casing via rotatable-linkage means. The reduction chamber includes a cylindrical rotationally symmetrical bore, having an axis Δ, for receiving the outer ring which has an outer cylindrical rotationally symmetrical shape that matches that of the receiving bore, the rotatable-linkage means including at least one torsion-damping pad which is mounted between the ring and the casing in order to damp the torque between the casing and the external ring, and which is at least partially inserted into a recess provided in the casing, the recess including at least one axial abutment suitable for forming an obstacle to the translation of the damping pad opposite the mounting surface.

Description

Starter head and starter equipped with such a head

[01] The present invention relates to the technical field of internal combustion engine starters. In a preferred but not exclusive application the invention relates to a motor vehicle internal combustion engine starter.

[02] Such a starter generally comprises an electric motor associated with drive means of the internal combustion engine. The drive means are most often adapted to be coupled to the movable members of the internal combustion engine during a start-up phase of the latter and to be uncoupled from the internal combustion engine when the latter is running. For this purpose the starter comprises an electromagnetic switch adapted to, firstly, control the power supply of the electric motor and, secondly, to control the coupling and uncoupling of the drive means from the combustion engine. internal. The drive means comprise a launcher which is rotatable on itself and is movable in axial translation between a rest position and a driving position of the internal combustion engine. The launcher is then moved between its rest and driving positions by a lever operated by the electromagnetic switch. Since the starting of the internal combustion engine requires a relatively large driving torque, the drive means comprise a gearbox which is interposed between the launcher and a drive gear of the electric motor.

[03] In order to have a starter as compact as possible, it has been proposed to implement an epicyclic gear reducer as is, for example, described in the applications FR 2 937 933 and WO 2005/0 54664. The starter then comprises a starter head comprising a housing which delimits a reduction chamber and which comprises means for fixing the electric motor. The starter head also comprises a speed reducer disposed in the reduction chamber and consisting of an epicyclic gear train comprising in particular planet wheels, intended to be rotated by the drive gear of the electric motor, and a outer ring of axis Δ, connected to the casing by rotating connection means. [04] Such a starter head and the starter, which integrates it, give full satisfaction with regard to their starting function in the early stages of their use. However, it appears that after a certain period of use of this starter, the moving parts of the starter head are likely to deteriorate so that the starter is no longer able to perform its function and it must be changed. After study, it seems that one of the causes of these malfunctions could be the shocks suffered by the rotating parts, the launcher and the gearbox, during the engine start during the first explosions occurring in the cylinders before uncoupling the starter. These shocks are notably due to speed variations that induce an inertial torque.

[05] It therefore appeared the need for a new starter head that is able to withstand these shocks without deteriorating so as to offer greater reliability and longevity of operation than starters according to the prior art.

[06] In order to achieve this object the invention relates to a starter head for an internal combustion engine starter, comprising:

a housing which delimits a reduction chamber and which comprises means for fixing an electric drive motor comprising a drive pinion,

- a speed reducer which is arranged in the reduction chamber and which comprises an epicyclic gear train comprising planet gears intended to be rotated by the drive gear of the electric motor, and an outer shaft of axis Δ, relegated to the casing by means of rotating connection,

According to the invention, this starter head for an internal combustion engine starter is characterized in that:

the reduction chamber comprises a cylindrical bore of revolution of axis Δ for receiving the outer ring which has a cylindrical external shape of revolution complementary to that of the receiving bore,

- The rotating connection means comprise at least one torsion damping pad which is mounted between the ring gear and the casing to damp a torque between the housing and the ring gear and which is engaged in part at least in a housing arranged in the housing, the housing comprising at least one axial abutment adapted to prevent a translation of the damping buffer.

- The implementation of rotational connection means between the outer ring and the casing, which comprise at least one damping pad advantageously allows to absorb shocks due to sudden variations in speed and torque forming an inertial torque, induced by the internal combustion engine in its starting phase while it is still coupled to the starter. Thus, the energy induced by these variations in torque and rotational speed is dissipated by the damping buffers thus avoiding a rupture of the teeth of the launcher, the various toothed wheels constituting the gearbox or the drive gear of the electric motor. It should be noted that, in view of the complementary shape of the outer ring and the receiving bore, in that the ring gear is rotatable relative to the casing, it results that in the absence of the connecting means in rotation the outer ring would be rotatable in the receiving housing so as to rotate 360 °.

[08] According to a feature of the invention, the torsion damping pad is mounted in axial compression in the housing between the axial stop and the ring. This prevents the inadvertent movement of the buffer or pads and thus prevents them from tearing.

[09] According to a feature of the invention, the torque between the housing and the ring is damped through dampers buffers and in that the rotation is stopped by at least this damping pad in compression. This prevents a too violent torque between the crown and the crankcase can cause a shock damaging all the equipment of the starter.

[10] According to one characteristic of the invention, the starter head further comprises at least one axial bearing forming an axial abutment adapted to prevent axial translation, the outer ring to the opposite of the mounting face.

[11] In addition, the presence of an axial abutment preventing the translation of each damping pad parallel to the axis Δ of rotation of the gearbox avoids inadvertent movements of the damping buffer (s) under the effect of the forces they undergo due to sudden variations in rotational speed and torque. This perfect setting of the damping buffers contributes to the safety of the maintenance of damping buffers to avoid dissociation with the crown. This improves the reliability of the starter head and the gearbox according to the invention and therefore the starter that integrates it.

[12] According to the invention, the damping pad can be made in any suitable manner. However, the damping pad is preferably made of an elastically deformable polymer material adapted to withstand the mechanical stresses as well as the temperature and chemical stress conditions specific to the environment of an internal combustion engine.

[13] According to a characteristic of the invention, aimed at guaranteeing the effectiveness of the damping of rotational speed and torque variations, the rotational connection means comprise at least three damping buffers each engaged in part at least in a housing arranged in the housing, each housing comprising at least one axial abutment adapted to prevent a translation of the corresponding damping pad of the gear unit to an end of the housing surrounding the pinion.

[14] According to another characteristic of the invention, each damping pad is immobilized in axial translation in both directions by, on the one hand, the axial stop of the casing and, on the other hand, the outer ring. This mounting method allows a simple immobilization of each damping buffer with a reduced number of parts so as to limit the manufacturing cost of the starter head according to the invention.

[15] According to one embodiment of the invention, the housing comprises a launcher chamber which is located opposite the mounting face relative to the reduction chamber while the starter head comprises, in the chamber launcher, an output shaft, axis Δ, which is rotated by the gearbox and carrying a launcher comprising a pinion for cooperating with a starting ring of a heat engine.

[16] According to a variant of this embodiment, the outer ring comprises a flange which carries a guide bearing of the output shaft. The integration from the flange to the outer ring reduces the number of components of the starter head according to the invention.

[17] According to a feature of this variant, the flange separates the reduction chamber from the launcher chamber. The separation thus produced makes it possible to protect the reduction assembly with a planetary gear train and possibly to confine lubricating greases in the reduction chamber.

[18] According to another characteristic of this variant, the rotating connection means are arranged in the launcher chamber. This feature makes it possible in particular to reduce the volume of the reduction chamber by using a portion of the volume of the launcher chamber which is not useful for the movements of the launcher.

[19] The invention also relates to a starter for a heat engine comprising a starter head according to the invention and an electric motor which is fixed on the housing and whose driving pinion drives the speed reducer.

[20] According to a feature of the invention, the starter comprises a closure plate of the reduction chamber interposed between the housing and the electric motor. This closure plate advantageously makes it easier to assemble the starter and to ensure confinement of the epicyclic gearbox.

[21] According to a variant of this feature, the closure plate ensures a locking of the axial translation of the outer ring.

[22] Of course, the various features, variations and embodiments of the invention may be associated with each other in various combinations to the extent that they are not incompatible or exclusive of each other.

[23] Furthermore, various other features of the invention emerge from the description made with reference to the accompanying drawings which illustrate a non-limiting embodiment of a starter head according to the invention and a starter incorporating this reducer of speed.

- Figure 1 is a schematic view of a starter for a heat engine according to the invention.

- Figure 2 is a partial perspective in axial section of the starter head according to the invention, illustrated in Figure 1. - Figure 3 is a section, according to the plane III-III of Figure 1, the constituent epicyclic gear train and intended to equip the starter shown in Figure 1.

- Figure 4 is a perspective showing on a larger scale a detail of Figure 3.

[24] As can be seen in FIG. 1, a starter D according to the invention for a heat engine comprises a starter head 1 on which is fixed an electric motor M controlled by an electromagnetic switch C which also controls an integrated launcher L to the damping system 1. The embodiment of such a starter and its components are well known to those skilled in the art so that only the characteristics necessary for understanding the invention will be described. For more information on the details of realization of a starter which would not be described later, it is possible to refer to the documents FR 2 934 933, FR 2 843 427 and WO 2005/054664.

[25] The starter head 1 according to the invention comprises a housing 2 on which the electric motor M is fixed. The casing 2 comprises fixing lugs 3 intended to allow attachment of the starter D on a heat engine that it intended to start. The casing 2 also comprises means 9 for fixing the electric motor M.

[26] As shown in Figure 2, the housing 2 is hollow and defines a reduction chamber 4 adjacent to a mounting surface 5 of the electric motor M on the housing 2. The reduction chamber 4 is extended, the opposite of the face 5, by a launcher chamber 6 inside which is the launcher L.

[27] The starter head 1 also includes a speed reducer 10 which is arranged in the reduction chamber 4. The reducer 10 comprises, as is apparent from Figure 3, an outer ring 11 which has a generally symmetrical shape of Δ axis revolution. The outer peripheral surface 12 of the ring 11 is smooth and cylindrical with axis A revolution while the inner peripheral surface 13 of the outer ring 11 is toothed. The inner toothed face 13 of the outer ring 11 cooperates with three planet gears 14 which are rotatable along axes parallel to the axis Δ. The planet gears 14 mesh a planet gear 15 coaxial with the outer ring 11. The planet gear 15 has a housing 16 for receiving the drive pinion 17 of the electric motor M. The housing 16 has a shape complementary to that of the pinion 17 of FIG. so that when the pinion 17 is engaged in the housing 16, the sun gear 15 is secured to a drive shaft of the axis motor Δ and not visible in the figures.

[28] As known to those skilled in the art, the planet gears 14 are integral with a plate 18 rotatably connected to an output shaft 19 coaxial with A'axe The output shaft 19 extends into the launcher chamber 6 being supported by rotation guiding means 20 disposed in a housing wall 2 opposite the gearbox 10. The output shaft 19 carries the launcher L which is rotatably connected to the output shaft 19 while being movable in translation on the latter between a rest position R, shown in solid lines in Figure 1, and a driving position E of the internal combustion engine illustrated in phantom in Figure 1. In this position E, the launcher L is intended to cooperate with a start ring, not visible in the figures, which extends partly inside the launcher chamber by a window 21 of the housing 2. The launcher L is moved between its rest positions R and E drive by a l sink 22 operated by the electromagnetic switch C.

[29] In order to ensure the rotational guidance of the plate 18 and the output shaft 19, the outer ring 11 comprises at its face facing the launcher chamber 6 a flange 25 which carries a guide bearing 26 of the output shaft 19. The flange 25 further contributes to separating the reduction chamber 11 from the launcher chamber 6 so as to protect the reducing assembly 10.

[30] The reduction chamber 4 comprises a cylindrical bore of revolution of axis Δ which has a shape complementary to that of the outer surface 12 of the outer ring 11. The ring is rotatable relative to the casing 2. outer ring 11 is mounted between on the one hand, an axial bearing surface 27, forming a stop, arranged in the reduction chamber 4, at the boundary between the latter and the launcher chamber 6, and on the other hand a portion of the closing plate 28 interposed between the casing 2 and the motor M. The closure plate 28 and the axial bearing surface 4 make it possible to limit the axial translation of the outer ring 11 and thus limit the axial deformation of the shock absorber pad 36. The plate closure 28 helps to confine the gears 14 and 15 as well as the inner surface 13 of the ring 11 so as to protect the gearbox 10. According to the example shown, the closure plate 28 comprises, at a bore central geometry 29, means for guiding the rotation of the induced shaft of the electric motor. [31] In order to allow transmission of the rotation of the drive pinion 17 to the planet gears 14 and thus to the output shaft 19, the outer ring 11 must be rotatably connected to the casing 2. For this purpose, it is implemented means 35 for rotational connection of the outer ring 11 with the casing 2. The rotational connection means 35 comprise at least one and, according to the illustrated example, six damping pads 36, only three of which are visible at the figure 2.

[32] Each damping pad 36 is engaged in a housing 37, housing 2, arranged in the wall of the launcher chamber 6 at its end towards the reduction chamber 4. Each housing 37 has a shape complementary to that of the corresponding damping pad 36 and is open towards the inside of the launcher chamber 6. Each housing 37 is, furthermore, open towards the reduction chamber 4 so as to allow the corresponding buffer 36 to engage in a translational movement. parallel to the a> fe In another example described, the bottom of the housing is inclined relative to the ax ^ (bottom housing is heard the face of the farthest housing ¾e (flange housing 37 also includes two side walls 38 each defined by an intermediate rib 39 which separates the housing 37 from an adjacent housing.Each housing extends from the peripheral wall of the launcher chamber 6 in a direct manner. substantially radial ion inward of said launcher chamber 6.

[33] The connecting means 35 also comprise a skirt 40 which extends from the flange 25 inside the launcher chamber 6. The skirt 40 forms with the flange 25 and the outer ring 11 a one-piece assembly. The skirt 40 comprises in relation to each pad 36 at least one radial rib 41 which extends inside said pad 36 so as to bind it to the skirt 40 is thus to the outer ring 11.

[34] In order to ensure a blocking of the movements of the buffers in axial translation, that is to say parallel to the axis \ each housing 37, detecting a damping pad 36, comprises at least one axial abutment 45 adapted to prevent a translation of the damping pad 36 parallel to the axis A towards the inside of the launcher chamber 6, opposite the reduction chamber 4. According to the illustrated example, the axial stops 45 are arranged in the wall of the launcher chamber 6 being separated from each other by notches 46 arranged in the wall of the launcher chamber 6. The notches 46 promote the circulation of a cooling air stream of the system 1. In addition these notches 46 allow a saving of material and therefore weight.

[35] The damping buffers 36 are further immobilized axially by the outer ring 11 located opposite the abutments axia 45 relative to the damping pads 36. Thus, each damping pad 36 is perfectly immobilized in its housing 37 of so that it is not likely to move under the effect of the shocks induced by the engine start torque variations of which the starter according to the invention ensures startup.

[36] According to the illustrated example, the outer ring 11 is made of plastic and the pads 36, made of viscoelastic material such as an elastomer, are overmolded on the latter so as to facilitate the assembly of the head of starter 1 and starter D according to the invention.

[37] Of course, such an embodiment is not strictly necessary for the invention and various modifications could be made to the embodiment of the invention described above, within the scope of the appended claims.

Claims

An internal combustion engine starter head, comprising:

- a casing (2) which delimits a reduction chamber (4) and which comprises a mounting face (5) of an electric motor M comprising a drive pinion (16),

a speed reducer (10) which is arranged in the reduction chamber (4) and which comprises an epicyclic gear train comprising planet gears (14), intended to be rotated by the drive pinion (16); ) of the electric motor (M), and an outer ring (11) of axis Δ, connected to the casing (2) by rotational connection means (35),

characterized in that

- The reduction chamber (4) comprises a cylindrical bore of axis A, receiving the outer ring (11) which has an outer cylindrical shape of revolution complementary to that of the receiving bore, in which the crown is rotatable relative to the housing

the rotational linking means (35) comprise at least one torsion damping pad (36) which is mounted between the ring gear and the casing (2) and is in contact with the card and the ring gear, to damp a torque between the housing (2) and the outer ring (11) and which is engaged in part at least in a housing (37) arranged in the housing (2), the housing comprising at least one axial stop (45) adapted to obstruct a axial translation of the damping pad (36) opposite the mounting face (5).

2. Starter head in which the torsion damper is mounted in axial compression in the housing between the axial stop and the crown.

3. Starter head in which the torque between the housing and the crown is damped by damping buffers and in that the rotation is stopped by at least this damping buffer in compression.

4. Starter head according to one of the preceding claims, characterized in that it further comprises at least one axial bearing forming an axial abutment adapted to prevent axial translation from the outer ring to the opposite of the mounting face (5).

Starter head according to one of the preceding claims, characterized in that the rotational connection means comprise at least three damping buffers (36) each engaged in part at least in a housing (37) arranged in the housing (2). ), each housing (37) comprising at least one axial stop (45) adapted to prevent a translation of the damper pad (36) opposite the mounting face (5).

6. Starter head according to one of claims 1 to 5, characterized in that each damping pad (36) is immobilized in axial translation in both directions, by, on the one hand, the axial stop (45) of the housing (2) and, on the other hand, the outer ring (11).

Starter head according to one of Claims 1 to 5, characterized in that:

the casing (2) comprises a launcher chamber (6) which is situated opposite the mounting face (5) with respect to the reduction chamber (4),

- It comprises, in the launcher chamber (6), an output shaft (19), of axis Δ, which is rotated by the gear (10) and which carries a launcher (L) comprising a pinion for cooperate with a starter ring of a heat engine.

8. Starter head according to any one of the preceding claims, characterized in that the outer ring (11) comprises a flange (25) which carries a guide bearing for an output shaft.

9. starter head according to claim 7 and 8, characterized in that the flange (25) separates the reduction chamber (4) from the launcher chamber (6).

10. Starter head according to claim 7 or 9, characterized in that the rotational connecting means (35) are arranged in the launcher chamber (6).

11. A starter for a combustion engine comprising a starter head according to one of claims 1 to 10 and an electric motor which is fixed on the housing (2) and whose driving pinion (16) drives the speed reducer (10). ).

12. Starter according to claim 11, characterized in that it comprises a closing plate of the reduction chamber (4) interposed between the housing (2) and the electric motor.

13. Starter according to claim 12, characterized in that the closure plate ensures a locking of the axial translation of the outer ring (11).