WO2017174952A1

WO2017174952A1 - Starter for motor vehicle heat engine provided with an improved overrunning clutch

Info

Publication number: WO2017174952A1
Application number: PCT/FR2017/050843
Authority: WO
Inventors: José MATEUS; Céline BERTHOD
Original assignee: Valeo Equipements Electriques Moteur
Priority date: 2016-04-08
Filing date: 2017-04-07
Publication date: 2017-10-12
Also published as: CN108884802A; FR3049986A1

Abstract

The invention relates mainly to a starter having a maximum torque Cmax in N.m comprising: a pinion belonging to a starter drive assembly mounted on a drive shaft, said starter drive assembly being movable between an inoperative position and an operative position; a front bearing assembled between a mounting and said drive shaft in order to guide the rotation of said drive shaft, a starter drive assembly; an overrunning clutch (73) comprising: a driven ring (76) comprising on the outer periphery thereof an inner track (77) with a radius R measured in mm, and a driving ring (78) comprising ramps (79) on the inner periphery thereof; and N rollers (82) each mounted between said inner track (77) and a corresponding ramp (79), each roller (82) comprising a pin (Y) having an axial length L measured in mm and a radius r measured in mm, characterised in that said overrunning clutch (73) has dimensions that comply with the following relation: ε =((Cmax/(1000N ⁵ ^/2*L*0.05))*((R+r)/(R*r))⁵ ^/2)^√2 and in that ε is between 300 and 700.

Description

STARTER FOR THERMAL VEHICLE ENGINE

AUTOMOBILE WITH AN IMPROVED FREE WHEEL

The present invention relates to a starter for a motor vehicle engine with an improved free wheel. In order to start an internal combustion engine, particularly a motor vehicle, it is known to use a rotating electric machine in the form of a starter provided with a launcher capable of transmitting rotational energy from the starter to a crankshaft. of the engine by means of a starter ring. This launcher is mounted movable in translation on a drive shaft between a rest position in which the teeth of a drive pinion are disengaged from the teeth of a starting ring integral with the crankshaft of the heat engine, and a position of activation in which the teeth of the drive pinion mesh with teeth of the starter ring. The connection between the launcher and the drive shaft is performed via splines formed in the driver cooperating with splines of complementary shape formed in the drive shaft.

In a manner known per se, the launcher comprises a free wheel roller interposed axially between the driver and the pinion. The freewheel comprises a driven ring rotatably connected to the drive pinion comprising on its outer periphery a bearing surface called "inner race", and a driving ring integral with the coach comprising ramps on its inner periphery. Rollers are each mounted between the inner track and a corresponding ramp. However, during the phases of actuation of the starter and in particular at the time of the impact of the driver abutting against a shoulder formed on a splined connection, the various elements of the freewheel tend to deviate abruptly from each other. others due to the presence of the stop on groove of an internal set of assembly. This phenomenon generates localized pressures on the edge of the tracks causing fatigue problems of the components. The invention aims to remedy this drawback by proposing a starter having a maximum torque Cmax in Nm comprising:

- A pinion belonging to a launcher mounted on a drive shaft, the launcher being movable between a rest position and an active position,

a front bearing mounted between a support and the drive shaft for guiding the drive shaft in rotation, a launcher comprising helical splines cooperating with helical splines of the drive shaft between a rest position and a drive shaft; active position and in that in active position, the launcher abuts against a shoulder of the drive shaft,

a free wheel comprising:

a driven ring comprising on its outer periphery an internal track of radius measured in mm, the driven ring being integral in rotation with the pinion, and

a driving ring comprising ramps on its inner periphery, the driving ring being integral in rotation with the drive shaft when the launcher is in the active position,

- N rolls each mounted between the inner track and a corresponding ramp, each roll comprising an axis having an axial length measured in mm and a radius measured in mm,

characterized in that the freewheel has dimensions such that it respects the following relation:

ε = ((C max / (1000N ^{5 2 *} L ^* 0.05)) ^* ((R + r) / (R ^* r)) ^{5 2} ) ²

and in that ε is between 300 and 700.

A 25% decrease in the value of the coefficient ε doubles the number of operating cycles of the starter. The definition of a starter respecting the range ε makes it possible to significantly reduce the level of contact pressure between the rollers and the rings in the so-called "spline abutment" starter configuration. In addition, the fact that the value of the coefficient ε is greater than 300 makes it possible not to have an oversized freewheel relative to the necessity. Indeed, an oversized free wheel drives a volume of the free wheel more bulky modifying the volume of a starter and therefore requires more space in the engine part of the vehicle which may be impossible for some vehicle. The fact that the value of the coefficient ε is less than 700 makes it possible to hold a number of cycles for the freewheel 250000.

For example with a value of the coefficient ε equals 600 can reach 400 000 cycle for the freewheel for starter between 2 and 2.2. For the same starter between 2 and 2.2kw except that the freewheel is dimensioned having a value of the coefficient ε of 1200 is used from 150000 cycle.

According to one embodiment, the starter comprises a pinion carrier comprising a pinion shaft having at one of its ends the driven ring. According to one embodiment, the starter comprises a length L between 6 and 15 minutes and in that the sum of R + r <20 mm.

According to one embodiment, the starter comprises a maximum torque Cmax of the locked rotor starter of 40N.m

According to one embodiment, the driven ring is in one piece of the same material with the pinion shaft.

According to one embodiment, the pinion shaft comprises at its other end a splined section, the pinion being rotatably mounted on the splined section of the pinion carrier by means of complementary shaped splines. In one embodiment, the starter comprises a driver comprising the driving ring, the trainer further comprising helical splines engaged with helical splines of a drive shaft.

In one embodiment, the freewheel is movable in translation by means of a control lever and helical splines between a rest position and an active position.

In one embodiment, the free wheel comprises pre-load springs each mounted between a rim of a ramp and a corresponding roller. In one embodiment, the drive gear mounted on the drive shaft is positioned outside a starter carrier. The fatigue resistance of such a system is improved which generates significant internal stresses due to the overhang of the shaft when the launcher is in the active position.

According to one embodiment, the starter further comprises a base plate carrying a ring and comprising:

a metal plate,

a bushing mounted on the drive shaft for guiding the drive shaft in rotation,

a plastic portion overmolded on the metal plate and the pad to make them integral with each other,

- The plastic portion comprising a plastic layer between an outer periphery of the pad and an inner periphery of the wafer. The plastic layer between the metal of the wafer and the pad makes it possible to support the angle taken by the pad generated by the bending of the drive shaft in order to limit edge overpressures.

According to one embodiment, the metal plate comprises a main portion and a shoulder extending axially with respect to the main portion on an end located on the side of the pad. This makes it possible, because of the local extra thickness of the metal plate obtained by the creation of the shoulder, to limit the overhang of the pad relative to the base plate and therefore to less stress the plastic around the pad when the starter is in operation. In one embodiment, the pad has an axial length greater than an axial thickness of the main portion of the metal plate. The invention is particularly advantageous for this type of configuration where the cantilever between the pad and the base plate is important.

According to one embodiment, the plastic portion comprises at least two abutment portions mounted between the ring gear and a cylinder head. This keeps the ring gear radially in the cylinder head. In one embodiment, the ring gear comprises projections extending from an outer periphery of the ring gear.

According to one embodiment, damping pads are mounted between the projections and the abutment portions of the plastic portion. Such a configuration makes it possible to damp the shocks suffered by the crown.

The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These figures are given for illustrative but not limiting of the invention.

Figure 1 is a longitudinal sectional view of a motor vehicle engine starter according to the present invention;

Figure 2a is a detailed longitudinal sectional view of a speed reducer according to the present invention;

Figure 2b is a sectional view of the base plate according to the present invention carrying the gear reducer crown; Figure 2c shows a detailed sectional view of the area between the shoulder and the pad of the base plate according to the present invention;

Figure 3 is a perspective view illustrating the mounting of the gearbox crown with the base plate according to the present invention; Figure 4 is a schematic cross-sectional view of the freewheel roller of the starter of Figure 1;

FIG. 5 shows the surface condition of a prestressed shot peened circlip and used with the starter of FIG. 1 for holding the base plate; FIG. 6 shows residual stress level curves of an elastic stop ring as a function of a depth in the material respectively for a non-blasted circlip and for a circlip having undergone prestressing shot peening; FIG. 7 shows so-called Wohler curves representative of the fatigue strength of a circlip by indicating the number of cycles that can be supported by a circlip with or without prestressing shot blasting for a given stress level. Identical, similar or similar elements retain the same references from one figure to another. In the description which follows, use will be made of an axial orientation from back to front corresponding to the right-to-left orientation of FIG. In other words, a front element is located on the drive pinion side 15, while a rear element is located on the opposite side, that is to say on the side of the rear plate 39.

Referring to Figure 1, the starter 10 according to the invention comprises a drive shaft 1 1, a launcher 12 mounted on the drive shaft 1 1 and having a drive gear 15. In addition, a motor Electrical 16 includes an inductor stator 17 and an armature rotor 18 mounted coaxially. The stator 17 surrounds the rotor 18, which is mounted on a shaft 19 of the electric motor 16. The rotor 18 is able to rotate about an axis X inside a cylinder head 21. The latter is secured to a metallic support 23 of the starter 10 intended to be fixed on a fixed part of the motor vehicle. The stator 17 comprises a plurality of magnetic inductor poles 26 carried by the inner periphery of the yoke 21. As a variant, the stator 17 comprises an inductor winding comprising two pairs of windings which are each wound around a pole mass integral with the yoke 21. Each winding is composed of a continuous conductor wound around the polar mass in the direction of its thickness so as to form concentric contiguous turns of increasing diameter.

The rotor 18 comprises a pack of sheets provided with grooves for mounting electrical conductors in the form of pins. These conductors are interconnected to form a rotor winding 27 in connection with conductive blades 30 belonging to a collector 31 with electrically insulating body integral with the shaft 19 of the electric motor 16. Alternatively, the coil 27 is continuous wire. Brushes 34 rub on the commutator blades 30 of the manifold 31 to supply the rotor winding 27. The brushes 34 belong to a brush holder 35 equipped with guide cages and to receive the brushes 34. These brushes 34 are biased towards the blades collectors 30 by springs 36 for example of spiral type. The brush holder 35 is integral with a metal rear flange 39 having in its central portion a housing for mounting a bearing 40 of the needle bearing type. The flange 39 serves for rotatably mounting the rear end of the shaft 19 of the electric motor 16. The front end of the shaft 19 penetrates, via a section of reduced section, inside a bore made in the rear part of the drive shaft 1 1, a bearing 43 being interposed between these two elements 19, 1 1.

The axis of the shaft 19 coincides with the axis X of the rotor 18 and with the axis of the drive shaft 11. The rear flange 39 serves as a centralizer at the rear end of the yoke 21 and is connected by tie rods to the support 23 of the starter 10. The metal yoke 21 is interposed clamping between the metal support 23 and the metal rear flange 39.

The starter 10 also comprises an electromagnetic contactor 46 extending parallel to the electric motor 16 by being implanted radially above it. The contactor 46 has a metal tank 47 carried by the support 23, and equipped with an excitation coil 48 provided with at least one winding. The tank 47 is closed at the rear by a cover 49 of electrically insulating material. Fixing the cover 49 is made by folding the material of the free end of the tank 47. Terminals 50, 51 are shaped to each form a fixed contact inside the cover 49. One of the terminals 50 is intended to be connected to the positive terminal of the battery, the other terminal 51 is connected via a cable brushes 34 positive polarity. In known manner, during the excitation of the coil 48, a mobile core 54 is attracted by magnetic attraction towards the fixed core 55 to, firstly, act after catching a game on a rod 56 carrying a contact mobile 57 to cause the closing of the contacts 50, 51 of the contactor 46 and feed the electric motor 16 of the starter 10, and, secondly, actuate a control lever 58 of the launcher 12.

The drive shaft 1 1 is rotatably mounted in a front bearing 61 of the support 23 via a pinion carrier 62. This front bearing 61 to guide the drive shaft 1 1 in rotation consists of for example by a ball bearing. The pinion carrier 62 comprises a hollow shaft 63 to allow the passage of the drive shaft January 1. Two bearings 64 are interposed between the outer periphery of the drive shaft January 1 and the inner periphery of the pinion carrier shaft 63 to allow a relative rotational movement between the two elements 1 1, 63. The outer periphery of the pinion shaft 63 is in contact with the inner periphery of the front bearing 61.

The drive pinion 15 is mounted to rotate with the pinion shaft 63 via axial splines formed in the inner periphery of the pinion engaged with axial splines of complementary shape formed in the outer periphery of the pinion. In addition, a shock absorption device 67 comprises a spring 68 urging the pinion 15 against a stop 69 in the idle state. In the event of an impact with the teeth of the starter ring, the spring 68 is compressed by the translational movement of the pinion 15 which then has a tendency to move back relative to the stop 69. It will be appreciated that the pinion 15 is mounted on the pinion. drive shaft 1 1 outside the support 23 of the starter 10. Such a starter configuration 10 called "outgoing gear" generates significant internal stresses due to the cantilever of the drive shaft 1 1 when the launcher 12 is in the active position.

The launcher 12 is slidably mounted on the drive shaft January 1 and comprises a driver 72 configured to be actuated by the control lever 58 pivoting, and a freewheel roller 73 interposed axially between the driver 72 and the carrier pinion 62. This freewheel 73 comprises a driven ring 76 located on the rear end side of the pinion carrier shaft 63. The driven ring 76 has on its outer periphery an internal track 77 clearly visible in FIG. embodiment, the driven ring 76 is a monobloc of same material with the pinion shaft 63. In addition, the driver 72 comprises a driving ring 78 of the freewheel 73 provided with ramps 79 on its inner periphery. The driving ring 78 is thus integral in rotation with the shaft 1 1 via the driver 72 when the launcher 12 is in the active position. A plurality of Y axis rollers 82 are mounted between the inner track 77 and a corresponding ramp 79.

The freewheel 73 has a plurality of pre-load springs 83 each mounted between a rim of a ramp 79 and a corresponding roller 82. The locking direction of the freewheel 73 is illustrated by the arrow A (see FIG.

The freewheel 73 preferably has dimensions such that it respects the following relation: ε = ((Cmax / (1000N ^{5 2 *} L ^* 0.05)) ^* ((R + r) / (R ^* r)) ² ) ²

It is specified that in this expression: N is at the power 5/2, the expression (R + r) / (R ^* r) is at the power 5/2, and the set is at the root power of 2, with

- Cmax being the maximum torque of the starter expressed in N.m. The torque Cmax is measured locked rotor under a voltage and a resistance equal to that of the battery and the corresponding wiring between the battery and the starter of the application considered,

N being the number of rollers 82,

Where R is the radius of the inner track 77,

Where L is the axial length of each roller 82 measured along the Y axis, and

where r is the radius of each roller 82,

the dimensions R, L, and r being measured in mm.

ε is between 300 and 700.

A 25% decrease in the value of the coefficient ε doubles the number of operating cycles of the starter. The definition of a starter respecting the range ε makes it possible to significantly reduce the level of contact pressure between the rollers 82 and the rings 76 and 78 while optimizing the size of the starter 10. For example for a diesel 2L, the starter will be chosen so that its Cmax at the starter and generated by the starter is between 35 and 40Nm usually.

For example, L is between 6 and 15 min and the sum of R + r <20 mm and the value of the coefficient ε about 500 + or - 10% for a maximum torque of the blocked rotor starter of 40 N.m makes it possible to have a good optimization of the volume of the freewheel with respect to the wear of a Star Start starter, that is to say of a vehicle cutting its engine as soon as the vehicle is stopped. The driver 72 further comprises a washer 86 defining with a transverse wall of the driver 72 a groove for receiving the fingers of the lower end of the lever 58 fork-shaped. The upper end of the lever 58 is mounted in a known manner to articulation on a rod 87 elastically connected to the movable core 54 via a spring 88, said tooth against tooth spring, housed in the movable core 54.

The driver 72 is internally provided with helical splines 90 in complementary engagement with external helical gears 91 carried by the drive shaft January 1 in the vicinity of its rear end of larger diameter (see Figure 1). The launcher 12 incorporating the freewheel 73 is thus driven in a translation movement when it is moved by the lever 58 between a rest position in which the pinion 15 is disengaged from the starting ring of the heat engine and an active position in the which pinion 15 is engaged with the starting ring of the engine. In the active position, the driver 72 abuts against a shoulder 93 made between the teeth 91 of the drive shaft January 1. This shoulder 93 of the drive shaft 1 1 is located axially between the base plate 106 and the front bearing 61.

Furthermore, as is clearly visible in FIG. 2a, a speed reducer 96 in the form of an epicyclic gear train is mounted between the rotor shaft 18 and the drive shaft 11. More specifically, the rear end of the drive shaft January 1 is configured to be secured to a plate of a planet carrier 97 for example by crimping. Satellites 101 mesh on the one hand with an outer planet ring 102 and on the other hand with a pinion 103 secured to the front end of the rotor shaft 19 forming an internal sun gear of the gearbox 96. The satellites 101 are mounted free to rotate each about an axis carried by the planet carrier 97. The satellites 101 are at least two in number. In this case, three satellites 101 are used.

The ring 102 is carried by a base plate 106 shown in detail in FIG. 2b integral with the cylinder head 21 of the engine by clamping between said cylinder head 21 and the support 23 of the starter 10. The base plate 106 comprises a metal plate 107, a bearing 108 mounted on the drive shaft 1 1 for rotating the drive shaft 1 1, and a plastic portion 109 overmolded on the plate 107 and the bearing 108 to make them integral with one of the other.

The plastic portion 109 comprises a plastic layer 1 12 between an outer periphery of the pad 108 and an inner periphery of the wafer 107 corresponding to an edge of the wafer 107 defining a central opening 1 16 for the passage of the shaft 1 January. Such a layer 1 12 clearly visible in Figure 2c can support the angle taken by the pad 108 generated by the bending of the shaft 1 1 to limit edge overpressure.

The thickness E of this plastic layer 1 12 is at least 0.5 mm. In order to minimize the pressure exerted by the drive shaft 1 1, it is possible to use a bearing 108 having an axial length greater than 5 mm.

In the embodiment of Figures 2b and 2c, the metal plate 107 comprises a main portion 1 14 and a shoulder 1 15 extending axially relative to the main portion 1 14 on one end of the plate 107 on the side of the Bearing 108. The shoulder 1 15 is thus located at the inner periphery of the wafer 107 around the central opening 1 16 of the wafer 107, while the main portion 1 14 extends from the shoulder 1 to 15 the outer periphery of the wafer 107. The wafer 107 thus has an excess thickness at the end located on the side of the pad 108. The pad 108 has an axial length L1 greater than the axial thickness L2 of the main portion 1 14 of the wafer 107.

Moreover, as is clearly visible in FIG. 3, the plastic portion 109 comprises at least two stop portions 120 mounted between the ring 102 and the yoke 21. These abutment portions 120 extending circumferentially around the ring 102 make it possible to hold the ring 102 radially in the cylinder head 21. The ring 102 attached to the base plate 106 includes projections 121 extending from an outer periphery of said ring gear 102. Damping pads 122 are mounted between the projections 121 of the ring 102 and the abutment portions 120 of the plastic portion 109. Such a configuration makes it possible to damp the shocks suffered by the ring 102 made for example of metal.

Alternatively, the ring 102 is part of the plastic portion 109. In this case, the teeth of the ring 102 are molded with an axial annular wall of the plastic portion 109.

In addition, in order to ensure the setting of the base plate 106, a holding element 125 taking for example the form of a circlip type elastic locking ring is positioned in a groove 126 of the drive shaft. 1 1 to abut against the base plate 106 (see Figure 2a). The elastic stop ring 125 has the shape of an open ring that can be deformed elastically with the aid of a tool to allow it to be positioned inside the groove 126. In order to absorb the shocks, the circlips 125 bears against a metal support washer 141 which bears against the plastic portion 109 of the base plate 108. As shown in FIG. 5, the elastic stop ring 125 includes traces of pre-stress shot peening impact 133 on at least its radial face opposite the base plate 106. To prevent the elastic locking ring 125 from being deformed in the prestressed state, the traces of shot peening impact of prestressing are located on the side of the two radial faces of the elastic stop ring 125.

As illustrated by the curve C1 of FIG. 6, the residual compressive stresses associated with the shot blast impact traces of prestressing at a depth in the material between 0 and 20μηη are between -600 and -1000 MPa. Comparatively, the residual stresses of an elastic stop ring which has not undergone prestressing shot peening (see curve C2) are positive. The prestressing shot peening applied on the elastic stop ring 125 is to be distinguished from the shot peening or deburring carried out at the end of the manufacturing process and which does not make it possible to obtain compressive stresses between - 600 and -1000 Mpa. In particular, the impact intensity of the media is thus much greater in the case of prestressing shot blasting than in the case of cleaning shot blasting.

Thus, by generating in the thickness of the elastic stop ring 125 compression stresses (negative stress) which oppose the tensile stresses (positive stress) generated by the stresses in use, the invention makes it possible to greatly improve the fatigue strength of the elastic stop ring 125.

Indeed, as is apparent from FIG. 7, for a given operating stress σ, the number of cycles N1 supported by an elastic stop ring 125 having undergone prestressing shot blasting (see curve C3) is much greater than number of N2 cycles supported by an elastic stop ring 125 having undergone a simple shot blast cleaning.

In an exemplary embodiment, the elastic stop ring 125 is made of steel and has undergone bainitic quenching treatment. The thickness of the elastic stop ring 125 is for example of the order of 2 mm plus or minus 10%.

Of course, the foregoing description has been given by way of example only and does not limit the scope of the invention which would not be overcome by replacing the different elements by any other equivalent.

Claims

1. Starter (10) having a maximum torque Cmax in Nm comprising:

- a pinion (15) belonging to a launcher (12) mounted on a drive shaft (1 1), said launcher (12) being movable between a rest position and an active position,

a front bearing (61) mounted between a support (23) and said drive shaft (1 1) for rotational guiding said drive shaft (1 1), a launcher (12) comprising helical splines co-operating with helical splines of said drive shaft (1 1) between a rest position and an active position and in the active position said launcher (12) abuts against a shoulder (93) of said drive shaft (1 1) ,

a freewheel (73) comprising:

- a driven ring (76) comprising on its outer periphery an inner track (77) of radius R measured in mm, said driven ring (76) being rotationally integral with said pinion (15), and

a driving ring (78) comprising ramps (79) on its inner periphery, said driving ring (78) being rotationally integral with said drive shaft (1 1) when said launcher (12) is in the active position,

- N rollers (82) each mounted between said inner track (77) and a corresponding ramp (79), each roll (82) including an axis (Y) having an axial length L measured in mm and a radius r measured in mm,

characterized in that said freewheel (73) has dimensions such that it respects the following relation:

ε = ((Cmax7 (1000N ^{5 2 *} L ^* 0.05)) ^* ((R + r) / (R ^* r)) ^{5 2} ) ²

and in that ε is between 300 and 700.

2. Starter according to claim 1, characterized in that it comprises a pinion carrier (62) comprising a pinion shaft (63) having at one of its ends said driven ring (76).

3. Starter according to claim 2, characterized in that said driven ring (76) is in one piece of the same material with the pinion shaft.

4. Starter according to claim 2 or 3, characterized in that said pinion carrier shaft (63) comprises at its other end a splined section, said pinion being rotatably mounted on said splined section of said pinion carrier (62) by through complementary grooves.

5. Starter according to any one of claims 1 to 4, characterized in that it comprises a driver (72) comprising said driving ring (78), said driver (72) further comprising helical grooves engaged with grooves helical of a drive shaft (1 1).

6. Starter according to claim 5, characterized in that said free wheel (73) is movable in translation by means of a control lever (58) and helical splines between a rest position and an active position.

7. Starter according to any one of claims 1 to 6, characterized in that said free wheel (73) comprises preloading springs (83) each mounted between a rim of a ramp (79) and a roller (82) corresponding.

8. Starter according to any one of claims 1 to 7, characterized in that said drive pinion (15) mounted on said drive shaft (1 1) is positioned outside a support (23) of said starter (10).

9. Starter according to any one of claims 1 to 8, characterized in that it further comprises a base plate (106) carrying a ring (102) and comprising:

a metal plate (107),

a bearing (108) mounted on said drive shaft (1 1) for rotating guide said drive shaft (1 1), a plastic portion (109) overmolded on said metal plate (107) and said pad (108) to make them integral with each other,

said plastic portion (109) comprising a plastic layer (1 12) between an outer periphery of said pad (108) and an inner periphery of said pad (107).

10. Starter according to claim 9, characterized in that said metal plate (107) comprises a main portion (1 14) and a shoulder (1 15) extending axially with respect to said main portion (1 14) on one end. located on the side of said pad (108).

1 1. Starter according to claim 10, characterized in that said pad (108) has an axial length (L1) greater than an axial thickness (L2) of said main portion (1 14) of said metal plate (107).

12. Starter according to any one of claims 9 to 1 1, characterized in that said plastic portion (109) comprises at least two abutment portions (120) mounted between said ring gear (102) and a yoke (21).

13. Starter according to any one of claims 9 to 12, characterized in that said ring gear (102) comprises projections

(121) extending from an outer periphery of said ring gear (102).

14. Starter according to claims 12 and 13, characterized in that damping pads (122) are mounted between said projections (121) and said abutment portions (120) of said plastic portion (109).