FR3065337A1 - THERMAL MOTOR STARTER WITH IMPROVED AXIAL SHAFT ADJUSTMENT - Google Patents

Abstract

The invention relates mainly to a starter (10) for a motor vehicle engine comprising: - an armature (17) mounted on an armature shaft (20) extending along an axis (X), - an inductor (16) ) mounted to surround the armature (17), and - a bearing having a housing (79) receiving a portion (202) of the armature shaft (20), and the starter being characterized in that further comprises a plate (78) disposed axially between the portion (202) of the armature shaft (20) and a bottom of the housing (79), and that an axial end of the shaft armature (20) has a zone (80) bearing against the plate (78), said zone extending radially along a length smaller than the diameter of the portion (202) of the armature shaft (20) .

Description

Holder (s): VALEO ELECTRIC EQUIPEMENTS MOTOR Simplified joint-stock company.

Extension request (s)

Agent (s): VALEO EQUIPEMENTS ELECTRIQUES MOTOR Simplified joint-stock company.

STARTER OF AN ENGINE WITH IMPROVED AXIAL SHAFT TIMING.

FR 3,065,337 - A1 (W) The invention relates mainly to a starter (10) for a thermal engine of a motor vehicle comprising:

- an armature (17) mounted on an armature shaft (20) extending along an axis (X),

- an inductor (16) mounted so as to surround the armature (17), and

- A bearing comprising a housing (79) receiving a portion (202) of the armature shaft (20), and the starter being characterized in that it further comprises a plate (78) disposed axially between the portion (202) of the armature shaft (20) and a bottom of the housing (79), and in that an axial end of the armature shaft (20) has a zone (80) bearing against the plate (78), said zone extending radially along a shorter length than the diameter of the portion (202) of the armature shaft (20).

IMPROVED ARMOR AXIAL TIMING THERMAL ENGINE STARTER

The invention relates to a thermal engine starter with improved armature shaft timing.

The invention finds a particularly advantageous, but not exclusive, application with the starters equipping vehicles equipped with the function of automatic stop and restart of the heat engine (so-called stop and start function) depending on the traffic conditions. .

In order to start a heat engine, in particular of a motor vehicle, it is known practice to use a starter provided with a launcher capable of transmitting rotation energy from the starter to a crankshaft of the heat engine via a start-up crown.

For this purpose, the launcher is mounted on a drive shaft. In addition, a speed reducer is interposed between this drive shaft and a shaft carrying the armature of the electric motor. The interposition of the reducer has the advantage of using a faster electric motor and thus obtaining a higher starting torque while reducing the size and weight of the machine for a given power.

In a conventional configuration, one end of the armature shaft is rotatably mounted relative to the drive shaft and the other end of this shaft is rotatably mounted relative to the rear bearing of the starter. To this end, as illustrated by FIG. 1, a bearing 1 is inserted radially between the external periphery of the end 2 of the armature shaft 3 and the internal periphery of the housing 4 of the rear bearing 5.

Furthermore, in order to avoid premature wear of the brushes as well as the generation of parasitic noise, it is important to limit the axial movement of the armature shaft 3. To this end, the permanent magnets of the inductor can be offset towards the bearing with respect to the center of the armature to apply a restoring force on the armature towards the rear bearing 5.

However, due to the combination of the restoring force applied by the magnets and the high speed of rotation at the external periphery of the armature shaft 3, the flanges 6 of the bushing 1 wedged between the shoulder 7 of the armature shaft 3 and rear bearing 5 tend to wear out quickly.

The invention aims to effectively remedy this drawback by proposing a starter for a thermal engine of a motor vehicle comprising an armature mounted on an armature shaft extending along an axis, an inductor mounted so as to surround the armature and a bearing comprising a housing receiving a portion of the armature shaft. According to the invention, the starter îo further comprises a plate disposed axially between the portion of the armature shaft and a bottom of the housing. In addition, according to the invention, an axial end of the armature shaft has a contact zone bearing against the plate, said zone extending radially along a length shorter than the diameter of the portion of the shaft d 'induced.

In other words, the contact area pressing against the plate is of reduced section compared to another section of the portion of the armature shaft inserted in the bearing housing. By reduced section is meant that the contact area has a radial section having a smaller area than that of a section of the portion of the shaft.

The invention thus makes it possible, thanks to the small contact surface between the armature shaft and the plate, to limit the contact surface between these two elements. This reduces friction between the two parts and therefore the wear of the plate and / or the shaft is minimized compared to a solution of the prior art.

According to one embodiment, the contact zone is centered relative to the portion of the armature shaft. In other words, the axis of the armature shaft and that of the contact zone are merged. Thus, the contact between the contact area of the armature shaft and the plate is made in a central area of the armature shaft. The speed of the surface of the armature shaft in contact with the plate is very low so that the friction and therefore the wear of the plate and / or of the armature shaft are further minimized.

According to one embodiment, the plate is interposed axially between the portion of the armature shaft and a bottom of the bearing housing so that the support of the axial end of the armature shaft on the plate is in an axial direction.

According to one embodiment, the plate radially and has the shape of a flat disc.

According to one embodiment, the contact zone consists of a shoulder extending from the axial end of the armature shaft.

According to one embodiment, the shoulder has a flat face bearing against the plate. According to another embodiment, the shoulder has a rounded face bearing against the plate.

According to one embodiment, the shoulder is connected to the portion by a chamfered zone.

According to one embodiment, the axial end of the armature shaft has a rounded shape, an apex of which forms the contact zone.

According to one embodiment, the rounded shape is a portion of a sphere. According to another embodiment, the rounded shape is a portion of ellipsoid.

According to one embodiment, the contact area is substantially punctual. The term “substantially punctual” is understood to mean having the smallest possible contact area while respecting the constraints of manufacturing and mechanical strength of such a holding part.

According to one embodiment, the plate is mounted clamped in the housing. This makes it possible to prevent movements of the plate in a simple and reliable manner and therefore contributes to reducing the wear of said plate.

According to one embodiment, the plate is fixed relative to the bearing.

According to one embodiment, the plate is made of a material based on treated steel. Preferably, the plate is then a stamped part.

According to another embodiment, the plate is made from a sintered material.

According to one embodiment, the contact area of the armature shaft is produced by machining.

According to one embodiment, the starter further comprises a bearing comprising an annular portion interposed between an external periphery of the portion of the armature shaft and an internal periphery of the housing.

According to one embodiment, the annular portion of the bearing is integral with the plate. In an alternative embodiment, the plate is separate, that is to say attached, relative to the annular portion of the pad.

According to one embodiment, the end of the shaft is of reduced diameter with respect to a section of the armature shaft.

According to one embodiment, the inductor is an inductor with permanent magnets.

According to one embodiment, a center of the permanent magnets of the inductor is offset in the direction of the bearing with respect to a center of the armature to apply a restoring force on the armature in the direction of the bearing.

According to one embodiment, the bearing is a rear bearing of the starter. In other words, the bearing is arranged at an axial end of the armature shaft opposite to the other axial end of said shaft which is opposite a reduction unit - starter launcher.

The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These figures are given only by way of illustration but in no way limit the invention.

Figure 1, already described, is a sectional view illustrating the mounting of one end of the armature shaft inside the housing of the rear bearing according to a known configuration.

Figure 2 is a longitudinal sectional view of a starter according to an example of the present invention.

Figure 3 is a partial sectional view of the rear part of the starter illustrating an example of a first embodiment of the invention.

Figure 4 is a partial sectional view of the rear part of the starter illustrating an example of a second embodiment of the invention.

Identical, similar or analogous elements keep the same reference from one figure to another.

In the description which follows, an axial orientation will be used from back to front corresponding to the orientation from right to left in FIG. 2. In other words, a front element is located on the side of the drive pinion, while a rear element is located on the opposite side with respect to the axis of rotation of the starter motor, that is to say on the side of the rear bearing.

îo As shown in FIG. 2, the starter 10 comprises a launcher 11 mounted on a drive shaft 12 and an electric motor 13 composed of an inductor stator 16 and an induced rotor 17 mounted coaxially one by compared to each other. The inductor stator 16 surrounds the armature 17 which is mounted on a shaft 20 of axis X called armature shaft. A cylinder head 21 is secured to a support 22 of the starter 10 intended to be fixed to a fixed part of the motor vehicle.

Still in the example of FIG. 2, a speed reducer 25 is interposed between the armature shaft 20 and the drive shaft 12. This speed reducer 25 is formed by an epicyclic train comprising satellite pinions 26 rotatably mounted around axes carried by a planet carrier 27 comprising a transverse plate 28 secured to the rear end of the drive shaft 12. These planet gears 26 mesh on the one hand with a sun gear 29 and d on the other hand with the internal teeth of a toothed ring 30 which is immobile in rotation relative to the support 22. The sun gear 29 may be constituted by a grooved section of the shaft 20 as is the case in the example shown, or by an attached pinion fixed on the armature shaft 20.

In known manner, the inductor 16 comprises a plurality of permanent magnets 31 carried by the internal periphery of the cylinder head 21. The center

C1 of the permanent magnets 31 of the inductor 16 is offset along the arrow D in the direction of the rear bearing 75 relative to the center C2 of the armature 17 to apply a restoring force on the armature 17 in the direction of the rear bearing 75.

Furthermore in this example, the armature 17 comprises a pack of sheets 33 provided with grooves for mounting electrical conductors in the form of pins. These conductors are interconnected to form a rotor winding 34 in connection with conductive strips 37 belonging to a collector 38 with an electrically insulating body secured to the armature shaft 17. As a variant, the winding is made of continuous wire.

Brushes 39 rub on the blades 37 of the collector 38 to supply the rotor winding 34. The brushes 39 belong to a brush holder 40 fitted with guide and receiving cages for brushes 39. These brushes 39 to are biased towards the blades 37 by springs.

The starter 10 also comprises an electromagnetic contactor 44 provided with a metal tank 45 carried by the support 22, and equipped with at least one excitation coil 46. The tank 45 is closed at the rear by a cover 47 made of electrically insulating.

Terminals 50 are shaped to each form a fixed contact inside the cover 47. One of the terminals 50 is intended to be connected to the positive terminal of the battery, the other terminal 50 is connected via 'a cable 51 to the brushes 39 of positive polarities.

In known manner, during the excitation of the coil 46, a movable core 54 is attracted by magnetic attraction in the direction of a fixed core 55 to, on the one hand, act after taking up a clearance on a rod 56 bearing a movable contact 57 for causing the closure of the contacts of the contactor 44 and supplying the electric motor 13 of the starter 10, and, on the other hand, actuating a control lever 60 of the launcher 11.

The upper end of the lever 60 is mounted in a known manner with articulation on a rod 61 connected elastically to the movable core 54 via a spring 62, called tooth against tooth spring, housed in the movable core 54. The lever 60 has in its middle part a pivot axis. The lower part of the lever 60 cooperates with a groove formed in the driver

65. Thus, during the displacement of the movable core 54, the rotation of the lever 60 causes a displacement in translation of the launcher 11 from a rest position in which the meshing pinion 67 is released from the starting crown of the heat engine. an active position in which the meshing pinion 67 is engaged with the teeth of the starter ring.

The starter 11 is slidably mounted on the drive shaft 12 and includes the driver 65 configured to be actuated by the control lever 60, a pinion body 66 carrying the meshing pinion 67, and a free wheel, by example with rollers 69, axially interposed between the driver 65 and the pinion body 66. The freewheel 69 makes it possible to decouple the meshing pinion 67 relative to the shaft 20 of the electric motor in over-speed operating phases. of the meshing pinion 67 driven by the starter ring of the heat engine. As a variant, the freewheel 69 may be interposed between the output of the speed reducer 25 and the drive shaft 12.

In known manner, the driver 65 is provided internally with helical splines engaged in a complementary manner with external helical teeth carried by the drive shaft 12. The launcher 11 is thus driven in a helical movement when it is moved by the lever 60 to come, via the pinion 67, in engagement with the starter ring (not shown), of a heat engine. A stopper 63 makes it possible to limit the axial movement of the pinion 67 when it moves towards its active position.

Furthermore, two bearings 71 are interposed between the pinion body 66 and the drive shaft 12, which is rotatably mounted relative to the support 22 via a bearing 72. The pinion 67 of the starter 11 is located inside the support 22. However, as a variant, this pinion 67 could be located outside of support 22.

The armature shaft 20 has a central section carrying the armature 17, a front portion 201 and a rear portion 202 axially opposite. The front portion 201 is of reduced diameter and penetrates inside a blind bore 74 formed in the rear face of the drive shaft 12. In an alternative embodiment not shown, the front portion 201 of the shaft armature 20 may also be protected by the reduction gear or by a part which can act as a front bearing.

The rear portion 202 of the armature shaft 20 is also of reduced diameter relative to the central section of the shaft 20 carrying the armature 17. Said portion 202 is rotatably mounted relative to the rear bearing 75 by means of a bearing 76 mounted, preferably by fitting, inside a housing 79 of the rear bearing 75. The bearing 76 is therefore fixed relative to the rear bearing. The bearing 76 has an annular portion 761 interposed between an outer periphery of the armature shaft 20 and an inner periphery of the housing 79. The annular portion 761 extending axially.

The starter 10 further comprises a plate 78 disposed axially to between the rear portion 202 of the armature shaft 20 and a bottom of the housing 79 of the bearing 75. The plate has the shape of a flat disc extending radially. Preferably, the plate 78 is mounted by tight fitting in the housing 79 so as to be fixed relative to the bearing 75 and therefore integral with the latter. The diameter of the plate 78 is therefore slightly reduced compared to the internal diameter of the housing 75.

The armature shaft 20 has a rear axial end extending opposite the plate 78 and having a contact area 80 which is in contact with the plate 78. The contact area 80 extends radially along a length more smaller than the diameter of the portion 202 of the armature shaft 20.

Preferably, the contact area 80 is located at the center of the axial end of said shaft.

In the embodiment of FIG. 3, the contact zone 80 is formed by a shoulder 81 having a diameter less than that of the section of the armature shaft 20 in contact with the annular portion 761 of the bearing 76.

The shoulder 81 has a flat transverse face bearing against the bottom wall 762 of the pad 76. As a variant, the transverse face of the shoulder 81 could have a rounded shape such as a portion of a sphere or of an ellipsoid. The shoulder 81 extends in perpendicular projection from the rear portion 202. In an alternative embodiment, a chamfered zone could extend between the rear portion 202 and the shoulder 81. For example, the chamfer may have a straight or curved shape.

In the embodiment of Figure 4, the contact area 80 has a rounded shape 83 bearing against the plate 78. Thus, the entire surface of the axial end of the armature shaft 20 has the rounded shape. The rounded shape 83 is, for example, a portion of a sphere. In this case, the armature shaft 20 has at its end in contact with the plate 78 a shape of a hemisphere. In an alternative embodiment, the rounded shape 83 may be a portion of ellipsoid. According to this configuration, the contact between the contact zone 80 of the armature shaft 20 and the plate 78 is almost punctual, which makes it possible to limit friction between the armature shaft 20 and the plate 78 as much as possible.

Preferably, the contact zone 80 is formed on the axial end of the armature shaft 20 by machining. Still preferably, the plate 78 is formed by stamping.

For example, the plate 78 is made of a material with a steel core treated as in the example illustrated in FIG. 4. In an alternative embodiment, the plate 78 can be made from a sintered material as in example illustrated by figure 3.

In the case where the plate 78 is made from a sintered material, the plate 78 may be in one piece with the annular portion 761 of the pad 76, as shown in FIG. 3, and form a bottom wall 761 of the pad 76. The bottom wall 762 is then extended at its outer periphery by the annular portion 761 of axial orientation relative to the axis X. Alternatively, the bottom wall 762 is distinct relative to the annular portion 761 of the pad 76.

Of course, the foregoing description has been given by way of example only and does not limit the scope of the invention from which one would not depart by replacing the various elements with any other equivalent.

Furthermore, the various features, variants, and / or embodiments of the present invention can be combined with one another in various combinations, insofar as they are not incompatible or mutually exclusive of one another.

Claims (13)

1. Starter (10) for a thermal engine of a motor vehicle comprising: - an armature (17) mounted on an armature shaft (20) extending along a 5 axis (X), - an inductor (16) mounted so as to surround the armature (17), and - A bearing comprising a housing (79) receiving a portion (202) of the armature shaft (20), and the starter being characterized in that it further comprises a plate (78) disposed axially between the portion (202) of the armature shaft (20) and a bottom of the housing (79), and in that an axial end of the armature shaft (20) has a contact zone (80) resting against the plate (78), said zone extending radially along a length shorter than the diameter of the portion (202) of the armature shaft (20). 15 2. Starter according to claim 1, characterized in that the contact zone (80) is centered relative to the portion (202) of the armature shaft. 3. Starter according to claim 1 or 2, characterized in that the contact zone (80) consists of a shoulder (81) extending from the axial end of the armature shaft (20). 20 4. Starter according to claim 3, characterized in that the shoulder (81) has a flat face bearing against the plate (78). 5. Starter according to claim 3, characterized in that the shoulder (81) has a rounded face bearing against the plate (78). 6. Starter according to any one of claims 3 to 5, 25 characterized in that the shoulder (81) is connected to the portion (202) by a chamfered zone. 7. Starter according to claim 1 or 2, characterized in that the axial end of the armature shaft (20) has a rounded shape (83), an apex of which forms the contact area (80). 8. Starter according to claim 7, characterized in that the rounded shape (83) is a portion of a sphere. 9. Starter according to any one of claims 1 to 8, characterized in that the plate (78) is mounted clamped in the housing 5 (79). 10. Starter according to any one of claims 1 to 9, characterized in that the plate (78) is made of a material based on treated steel. 11. Starter according to any one of claims 1 to 9, îo characterized in that the plate (78) is made from a sintered material. 12. Starter according to any one of claims 1 to 11, characterized in that it further comprises a bearing (76) comprising an annular portion (761) interposed between an external periphery of the portion (202) of the armature shaft (20) and an inner periphery of the housing (79). 13. Starter according to claim 12 when dependent on claim 11, characterized in that the annular portion (761) of the bearing (76) is in one piece with the plate (78). 1/2 PRIOR ART