GB2028934A

GB2028934A - Improvement in Starters of Internal Combustion Engines

Info

Publication number: GB2028934A
Application number: GB7926082A
Authority: GB
Original assignee: Societe de Paris et du Rhone SA
Current assignee: Societe de Paris et du Rhone SA
Priority date: 1978-08-01
Filing date: 1979-07-26
Publication date: 1980-03-12
Also published as: IT1122374B; ES245331Y; DE2930885A1; DE2930885C2; FR2432620B1; GB2028934B; ES245331U; IT7924804A0; FR2432620A1

Abstract

An actuator for a starter motor for an internal combustion engine has a free-wheel device 3 including wedgeable members 6 inside a cage 7. Between the cage 7 and the drive 1 is a plate 12 with a hub (12a) which fits over the shaft of the starter motor with the minimum working clearance. The plate 12 has projecting members 12b which cooperate with the wedgeable members 6. The plate 12 acts to centre both the cage 7 and the driver 1 with respect to the shaft. It may also transmit torque from the driver 1 to the cage 7. The plate 12 may be made in one piece with the driver 1 (Fig. 5, not shown). This construction ensures good centering while being relatively cheap and simple. <IMAGE>

Description

SPECIFICATION Improvements in Starters of Internal Combustion Engines The present. invention relates to improvements in actuators for electric starters of internal combustion engines.

Starter actuators are known in which a driver slides on the shaft of the electric starter motor and cooperates with helical ribs thereof, and a pinion meshes-with the crown wheel of the internal combustion engine in order to turn it. The driver and pinion are connected by a free wheel so that, if the pinion rotates more quickly than the driver, it can freewheel with respect to the driver.

To prolong the life of the free wheel, all the rollers which cause relative jamming of the driver and of the pinion must act at the same time.

Under these conditions, the outer cage of the free wheel which is fastened to the driver must be perfectly concentric with respect to the inner track of the free wheel which forms part of the pinion. To attain this result, a complex structure is usually provided, increasing the cost of the actuator. To reduce costs by reducing machining, it has been suggested-that the cage of the free wheel be made independent of the driver, but no actuator thus produced is entirely satisfactory.

German Patent No. 966,553 discloses the use of a plate with a central hub through which the shaft of the starter passes and which has projections adapted to limit the movement of the rollers of a unidirectional system. French Patent No. 7,535,830 shows a flange fast with the driver of a starter, this flange being provided with teeth adapted to engage in depression made in the cage of the unidirectional system.

By use of a member the structure of which is disclosed by German Patent No. 966,553, two functions may be performed which prolong the life of the starter, viz.

-the centering of the cage of the unidirectional system with respect to the shaft of the starter; -the centering of the driver with respect to the shaft.

According to the invention there is provided an actuator for the starter motor of an internal combustion engine having a driver which is driven by and is movable axially along the shaft of the starter motor and a pinion which is driven by the driver through a free-wheel which comprises wedgable elements which in one direction of relative rotation of the driver and the pinion become wedged between the pinion and the driving cage around the pinion, said elements being spring-biassed towards the wedged position, the actuator further including a centering member having a hub portion adapted to be received on the shaft of the starter motor substantially without clearance, the centering member engaging the driver and the cage so as to center both with respect to the shaft.

Embodiments of the invention given by way of example will now be described with reference to the accompanying drawings, in which: Fig. 1 is a longitudinal section through an actuator according to the invention; Fig;2 is a transverse section therethrough. on the line il-lI of Fig. 1; -Fig. 3 is a view in elevation of a plate of the actuator of Fig. 1; Fig. 4 is a section on the line IV--IV in Fig. 3; Fig. 5 is a view similar to that of Fig. 1 but showing a variant embodiment; and Fig. 6 is a section thereof on the line VI--VI of Fig. 5. The plane of the section of Fig. 5 is shown in Fig. 6 at V-V.

Referring now to the drawings, Fig. 1 shows an actuator of an electric starter comprising a driver 1 and a pinion 2 connected by a free wheel 3.

The driver 1 has a bore 1a with a series of helical grooves shown schematically at 1 b adapted to cooperate with ribs arranged on the periphery of the shaft (not shown) of the electric motor of the starter. The periphery of the driver 1 is in a conventional manner provided with a disc 1 C adapted to receive.the action of a rocking lever (not shown). The driver also has an end flange 1 d of which the outer face its provided with axial projections 1 e.

The periphery of pinion 2 has a right-hand toothing 2a at one end and a smooth surface at the other end 2b separated by a groove 2c. The bore of the pinion 2 receives two. bearings 4 and 5 intended to facilitate the rotation of the pinion with respect to the shaft of the electric motor and to improve its guidance. The smooth outer surface of the end 2b forms the inner track of the free wheel 3, which has four rollers 6. The outer track of the free wheel is constituted by a cage 7 which maybe in one-piece or as here made in the form of a stack of washers 7'. The cage is associated with the flange 1 d of the driver by means of a cap 8 crimpedìover the flange and a circular plate 9 made in two parts and projecting into the groove 2c. A seal 1 is provided on the periphery of the plate 9.

-As shovvn in Fig. 2, the cage 7, i.e. each of the elementary washers 7', has ramps 7a, 7'a, which are not concentric with respect to the end 2b of the pinion 2, to allow the jamming of the corresponding rollers 6 which are each pushed by a spring 11.

Axially between the driver f and the cage 7 formed by the assembly of washers 7' there is disposed a plate 12 made of sheet metal, having a main flange-like portion and a central hub 1 2a which is adapted to rotate and to slide with functional clearance only with respect to a corresponding bearing surface of the shaft of the electric motor. It will be noted that the outside of the hub 1 2a is engaged without clearance in the bore of the driver 1 so that it acts like a bearing ensuring centering of the driver with respect to the shaft. As shown in Figs. 3 and 4, the disc of the plate 12 is cut so as to provide four tongues 1 2b which are bent to be perpendicular with respect to the general piane of the plate (Fig. 4).

The length of each tongue is equal to the width of the cage 7, i.e. the assembly of elementary washers 7'. There are also provided peripheral notches 1 2c in which the projections 1 e of the driver 1 are engaged. The flange-like web of the plate 12 is trapped between the opposed ends of the driver 1 and of the pinion 2, whilst the shaft of the electric motor passes through its hub. The tongues 1 2b penetrate without clearance in notches 7b, 7'b (Fig. 2) made axially in the bore of the washers 7'. The transverse section of the notches 7b, 7'b, is in the form of a V with unequal arms, open towards the axis of the shaft of the starter motor.

Thus the plate 12 performs three main roles: it firstly drives the cage 7 in rotation due to the cooperation of the projections 1 e of the driver and the peripheral notches 1 2c: secondly, due to the presence of the hub 1 2a and the tongues 12b, it ensures a perfect centering between the cage and the shaft; finally, the presence of said hub 1 2a centers the driver with respect to the shaft. As the shaft and the end 2b of the pinion are concentric due to the considerable length of the pinion and the presence of the two bearings 4 and 5, centering of the two tracks of the free wheel with respect to the shaft of the starter is effected. The openings 1 2d made to raise the tongues 126 could serve to receive the projections 1 e.

The driver 1 and the plate 12 could alternatively be made in one piece 13 (Fig. 5), advantageously cast in a suitable plastics material. Alternatively it could be metallic, either sintered or obtained by electro-erosion. In the case of a single piece 1 3 made of plastics material, the notches 76, 7'b would preferably be deeper so that the springs 11 abut entirely against the tongues 136 (Fig. 6). Thus, the slight elasticity of the tongues 136 would avoid premature wear of the corresponding end of the springs which occurs if they bear against a -- metallic surface.

It is possible, by use of the invention, to manufacture relatively cheaply an actuator in which the lifetime of the freewheel device is prolonged by accurate centering of the components.

Claims

1. An actuator for the starter motor of an internal combustion engine having a driver which is driven by and is movable axially along the shaft of the starter motor and a pinion which is driven by the driver through a freewheel which comprises wedgable elements which in one direction of relative rotation of the driver and the pinion become wedged between the pinion and a driving cage around the pinion, said elements being spring-biassed towards the wedged position, the actuator further including a centering member having a hub portion adapted to be received on the shaft of the starter motor substantially without clearance, the centering member engaging the driver and the cage so as to center both with respect to the shaft.

2. An actuator according to Claim 1 wherein the centering member includes a flange extending radially outwardly from its said hub portion and projecting portions extending axially from the flange and engaging the cage and acting as butments for springs spring loading said wedgable elements.

3. An actuator according to Claim 2 wherein the centering member is made in one-piece of sheet metal, the hub portion being a tubular portion stamped out at the center.

4. An actuator according to any one of the claims 1 to 3, wherein the centering member is arranged to transmit torque from the driver to the cage.

5. An actuator according to Claim 4, wherein means for the transmission of torque to the cage include notches in the centering member in which projections of the driver are engaged, and axially projecting portions of the centering member which cooperate with notches made in the cage.

6. An actuator according to any one of the preceding claims, wherein the cage is composed or a plurality of washers stacked in the axial direction against one another.

7. An actuator according to Claim 1 or Claim 2 wherein the driver and the centering member are made in one piece.

8. An actuator according to Claim 7, wherein the single piece constituting the driver and the centering member is made of plastics materiai.

9. An actuator substantially as hereinbefore described and illustrated in Figs. 1 to 4 or Figs. 5 and 6 of the accompanying drawings.

10. A starter for an internal combustion engine, including an actuator according to any one of the preceding claims.