US3299719A - Starter drive for internal combustion engine - Google Patents

Description

Jan. 24, 1967 P. TOULIER 3,299,719

STARTER DRIVE FOR INTERNAL COMBUSTION ENGINE Filed April 6, 1965 3 Sheets-Sheet l STARTER DRIVE FOR INTERNAL COMBUSTION ENGINE Filed April 6, 1965 P. TOULIER Jan. 24, 1967 3 Sheets-Sheet 2 Fig. 8

1967 P. TOULIER 3,299,719

STARTER DRIVE FOR INTERNAL COMBUSTION ENGINE Filed April 6, 1965 3 Sheets-Sheet 15 United States Patent 3,299,719 STARTER DRIVE FOR INTERNAL CGMIBUSTIQN ENGINE Pierre Toulier, Ville dAvray, France, assignor to Societe Anonyme D.B.A., Paris, France, a company of France Filed Apr. 6, 1965, Ser. No. 446,028 Claims priority, application France, Apr. 8, 1964, 970,204 12 Claims. (Cl. 74-7) The present invention relates to a starter drive for internal combustion engine in which the coupling member, such as pinion cooperating with a toothed wheel, is operatively connected by a free wheel, or any similar unidirectional clutch device, to a sleeve member threaded on the shaft of the starting motor.

This device is characterized in that means are associated with said sleeve member to create a friction torque opposing the rotation of said sleeve thereby causing the movement of said pinion toward said toothed wheel and then causing said pinion to stay in meshing engagement therewith during the starting of the internal combustion engine and in that resilient means are provided to urge as a unit, the pinion, the free wheel and the sleeve member back into a position in which the pinion is disengaged from the toothed wheel. The friction torque applied to the sleeve member by the aforesaid friction means has, according to the invention, a value which is larger than that of the friction torque applied to the sleeve member in opposition by the unclutched unidirectional device when the internal combustion engine is started, the remaining differential torque being adapted to generate in cooperation with the threaded operative connection between the sleeve member and the shaft of the starting motor, an axial thrust toward said toothed wheel superior to the thrust exerted in the opposite direction by said resilient returning means.

The device broadly defined hereinabove presents a peculiar advantage with respect to the known device (called positively operated starter) since its operation is controlled by a simple switching on of the electric starting motor without the necessity of providing a special control means, such as a solenoid for instance, for engaging the pinion with the toothed wheel before energizing the electric starting motor.

The device of the invention avoids premature disengagement of the pinion which occurs frequently in intertial starting devices wherein as the result of ignition in one cylinder alone, the pinion may be kicked out of the toothed wheel.

The device of the invention presents advantages in comparison to those devices known in the trade under the name FOLO-TI-IRU both from the point of view of simplicity of construction as well as reduction in size. Furthermore it achieves an increased reliability in that the return of the pinion to its retracted position no longer depends upon delicate and costly centrifugal de-clutching.

Other characterizing features of the invention will appear in the following specification in which reference is made to the accompanying drawings in which:

FIG. 1 shows a starting apparatus according to the invention with its pinion out of the toothed wheel.

FIG. 2 shows the device of FIG. 1 in starting position i.e. with its pinion meshing with the toothed wheel.

FIG. 3 is a partial cross-section view taken along line 3-3 of FIG. 2 showing more particularly the friction means cooperating with the sleeve member of the starting device.

FIG. 4 shows a friction washer used to constitute the friction means.

FIG. 5 shows in partial cross-section a starting device according to another embodiment of the invention com- Patented Jan. 24, 1967 prising the use for a friction plate which is laterally guided.

FIG. 6 shows resilient returning means of the unit comprising the sleeve member and the pinion of the embodiment of FIG. 5.

FIGS. 7 and 8 show in longitudinal cross-section, with parts broken away, a starting device according to another embodiment of the invention, in .the inactive and in the active positions respectively.

FIG. 9 is a transversal cross-section of the device of FIGS. 7 and 8 passing through the rocking axis of the fork and between the two friction plates.

FIG. 10 is a cross-section along the line 1010 of FIG. 9.

FIG. 11 is a cross-section along line 11--11 of FIG. 10.

FIG. 12 is a perspective view of the spring biasing the fork of the device of FIGS. 7 and 8.

FIGS. 13 and 14 show in longitudinal cross-section, with parts broken away, a starting device according to still a further embodiment of the invention, FIG. 13 showing this device in the inoperative state and FIG. 14

' the same device in the operative state.

FIG. 15 is a cross-section along line 1515 of FIG. 14.

A starting device for internal combustion engine according to the invention will be described hereinafter with reference to FIGS. 1 to 4. In these figures, reference numeral 10 designates the shaft of the starter drive; reference numeral 12 designates a pinion which is adapted to freely slide on the shaft 10 and which is connected by means of a free wheel roller clutch, disc clutch or like unidirectional clutch device 14, to a threaded sleeve member 16 adapted to be threaded on a long pitch thread 18 of the shaft 10 of the starter drive. The sleeve member 16 is provided with a fiat surface 20. On the sleeve member 16 are slipped on two flat washers 22 and 24 comprising a central opening the shape of which is such that said washers 22 and 24 cooperate with the sleeve 16 and the fiat surface 20 thereof to be driven into rotation by said sleeve 16. Between the washers 22 and 24 is pressed 3 plate 26 comprising diametrally opposed lugs 27 engaging slots 29 provided at both ends of a fork 31 pivotally mounted by its upper portion about a pin 33 solid with the bearing forming portion of the devices body. A compression spring 35 acts upon the fork 31 to urge plate 26 in contact with washer 22, the latter being itself applied upon a snap-ring 30 fastened on sleeve member 16. Plate 26 comprises a circular opening having in diameter slightly larger than the diameter of sleeve 16 so that said plate may freely rotate about said sleeve member. A compression spring 28 is provided between the shoulder formed by free wheel 14 and sleeve member 16, and the washer 24 to urge said washer 24 against plate 26.

It is easily understood that a convenient choice of thespring 28 causing the plate 26 to be pressed between washers 22 and 24 provides the friction means restraining the rotation of sleeve member 16. The thrust of spring 28 is so chosen that a friction torque applied by the plate 26 to the sleeve member 16 is .higher than the resisting torque proper to free wheel device 14 when the latter is in its unclutched state, pinion 12 being driven by the toothed wheel 40 of the internal combustion engine.

The compression spring 35 acting upon fork 31 takes support on the bottom of a cavity provided in the bearing of the electric starting motor and exerts upon fork 21 a thrust which is sufiicient to return backward and maintain in inoperative position the Whole of the sliding components cooperating with the sleeve member 16 when the rotary speed of the rotor shaft 16 is less than a given value as will be explained hereinafter when the operation of the device will be described.

A stop ring 11 axially positioned on shaft by means of a snap ring 13 is used to limit the axial stroke of the plurality of components sliding with the sleeve member 16 in a position in which the pinion 12 meshes with the toothed wheel 40.

The operation of the device described hereinabove is the following:

The electric starting motor being energized, the splines 18 of shaft 10 cooperate with the corresponding splines of the sleeve member 16, the rotary motion of which is restrained by the friction effect of plate 26 on washers 22 and 24 pressed against said plate. It results therefrom that the unit constituted by pinion 12-free wheel 14 and sleeve member 16 is pushed to mesh with the toothed Wheel 40 until pinion 12 abuts stop member 11. It is to be noted that the travel of pinion 12 toward toothed wheel 40 is obtained even though the inertia of the plurality of components operatively connected to sleeve member 16 is low since this travel movement is obtained because of the friction created upon the sleeve member by plate 26. The provision of long pitch splines (this pitch can be, for instance, of the order 5 to 20 times the diameter of the shaft) permits obtaining a quick axial travel of pinion 12 which thus meshes with toothed wheel 40 in a very short period of time at a rotary speed which is sufficiently low. Thus can be avoided a failure of pinion 12 or toothed wheel 41!. It is to be noted that after the teeth of pinion 12 have meshed with the teeth of toothed wheel 40, the internal combustion engine being still unstarted, pinion 12 is restrained in rotation by toothed wheel 40 and its axial travel in the teeth of the toothed wheel continues Without any further use of the friction effect of plate 26 against sleeve member 16 which has facilitated the initial axial travel.

While the starting motor .is kept rotating, pinion 12 drives the internal combustion engine by means of toothed wheel 40. If after a certain time during which the toothed wheel 40 is driven by pinion 12 the internal combustion engine cannot be started, it is obvious that when the operator cuts off the electric supply to the starting motor, the plurality of parts comprising pinion 12 freewheel 14 and sleeve member 16 are returned backward under the action of spring 35 pushing upon fork 31 (toward the right when considering the drawing) until the sleeve member 16 is brought in abutment against shoulder 41 of shaft 10, this corresponding to the retracted posi tion of the pinion .12 (FIG. 1).

When the internal combustion engine is starting whether after an isolated explosion or a correct starting, the toothed wheel 40 is driving pinion 12 at a rotary speed which can be higher than the speed that has been communicated to said pinion by the electric starting motor. In this case, the free wheel 40' operates to avoid an overspeed driving of the starting motor by the internal combustion engine.

So long as the operator maintains the electric supply circuit of the starting motor switched on, the latter keeps driving the sleeve member 16 and the portion 14a of free wheel 14 solid therewith. Since the internal combustion engine rotates, the toothed wheel 40 is driving pinion 12 (and the portion 14b of the free wheel solid with said pinion) in the same direction as portion 14a but at a higher rotary speed (the free wheel being de-clutched). The de-clut-ched free wheel 14 transmits to sleeve member 16 a friction torque which tends to override the torque generated by plate 26 together with washers 22 and 24 and thus to move sleeve member 16 in a direction corresponding to the disengagement of pinion 12. The resilient means (spring 35) acting upon the sleeve member 16 through fork 31 and plate 26 assists this disengagement. The condition that has to be fulfilled in order so that pinion 12 remains engaged in toothed wheel 40 can thus be expressed as follows: the resisting torque that the unclutched free wheel transmits to the sleeve memher (for a given speed of pinion driven by toothed wheel) must be low enough when compared to the friction torque generated by plate 26 acting on the sleeve member 16 (at a given speed of the electric motor) so that the resulting torque applied to sleeve member .16 generates (by cooperation of the splines of sleeve member 16 with the corresponding splines 18 of shaft 10) an axial thrust which is opposed (and higher in absolute value) to the one exerted by spring 35 upon sleeve member 16. It is to be noted that the friction forces in the free wheel depend on the construction, and the same is also true of the friction coeflicient existing between the splines of the sleeve member and the splines of the shaft. Furthermore, the strength of the spring 35 is so chosen that the latter opposes an undesired forward travel-of pinion 12 resulting from vibrations and causes the retraction of said pinion after the engine has been started and the pinion is disengaged. It results from the foregoing that particular attention should be paid to the value of the friction forces applied by Washers 22 and 24 to plate 26 i.e. to the strength of spring 28, to the area of the washers and to the nature of the contact surfaces to maintain pinion 12 in engagement in toothed wheel 40 when the starting motor is energized for given starting conditions of the internal combustion engine. It is necessary to obtain that the friction torque applied by plate 26 to sleeve member 16 for a rotary speed of the electric starting motor near the speed obtained in unloaded condition at the minimum voltage remains higher than the resisting torque transmitted by the free wheel with a positive difference such that the axial thrust of the sleeve member opposes the thrust of the resilient returning means (spring 35, fork 31), these conditions can be fulfilled even for a high rotary speed of toothed wheel 40.

After the internal combustion engine has been started, the operator switches off the electric starting motor, the resisting torque of the free Wheel 14 becomes preponden ant and the unit comprising pinion 12-free Wheel 14 and sleeve member 16 is returned in disengaged position. This motion is first caused by the combined action of the free wheel (causing the threading of the splined sleeve member 16 on the splines of shaft 10) and of fork 31 which is pushed by its spring 35. When pinion 12 is out of toothed wheel 40, the return motion is continued under the exclusive action of spring 35 as already explained in the case of the backward motion following a refusal to start of the internal combustion engine.

It is obvious that it is possible to use other static restraining friction means applied upon sleeve member 16 than those comprising washers 22 and 24 pressed against plate 26 and also other resilient returning means than fork 31 urged by its spring 35.

In another embodiment corresponding to FIGS. 5 and 6, the friction plate has been given a shape such that its lateral lugs cooperate with lateral guiding means solid with the body of the electric motor thus permitting an axial movement of the sleeve member While restraining the rotation thereof. In FIG. 5, there is shown a plate 50 the lugs 52 of which comprise slots 54 encompassing longitudinal ribs 56 provided on the inner Walls of a bearing forming element 58 parallel to the axis of shaft 60. The mounting of plate 50 on the sleeve member 62 between friction washers (not shown) is similar to the mounting that has been described hereinabove with reference to plate 26 on sleeve member 16.

The return means of sleeve member 62 in the present embodiment could obviously act upon plate 50, however as shown in FIG. 6 there has been provided, a helical compression spring 63 on shaft 60 to urge pinion 64 of the device in a direction corresponding to the disengagement thereof. Spring 63 takes support on an end stroke stop 66 comprising a recess 68 adapted to receive such spring when pinion 64 engages said stop 66 after having meshed with toothed Wheel 70.

The starting apparatus comprising the friction means including plate 50 and resilient returning means such as spring 63 operates obviously in a manner similar to the device described hereinabove with reference to FIGS. 1 to 4 in which have been shown other types of friction means and returning means.

The two other embodiments that will be now described comprise many improvements having particularly in view to avoid and compensate clearances between the different parts in relative motion which is particularly important in devices of this kind.

The starter drive represented in FIGS. 7 to 9 generally comprises a body 80 including an electric starting motor of which has been represented in partial'crosssection, the statorat 82 and the rotor at 84. Rotor 84 has the forward portion of its shaft 86 which is received in the bearing forming and 88 of body 80, between the bearing forming portion 88 and the rotor 84, the shaft 86 comprises a cylindrical portion 90 and a long pitch threaded portion 92. On the cylindrical portion 90 is slidably and rotatably mounted a pinion 94 with interposition of a coaxial sleeve 96. On the threaded portion 92 is threaded a sleeve member 98,

the inner wall of which comprises splines cooperating with the corresponding splines of portion 92. As shown in FIGS. 7 and 8, the rearward portion 97 of pinion 94 and the forward portion 100 of sleeve member 98 constitutes the inner and the outer races respectively of a free wheel generally designated by reference numeral 102. Free wheel 102 is of a known type, there has been represented at 104 the rollers thereof and at 106 its housing crimped upon the portion 97 of pinion 94 and upon the portion 100 of sleeve member 98 respectively. Free wheel 102 comprises an internal compression spring 108 biasing parts 97 and 100 away from one another, said parts 97 and 100 being in engagement, as shown in FIG. 8, when the device being in operative condition, pinion 94 which meshes with the corresponding toothed wheel 112 is in abutment against a ring 114 fastened on portion 90 of shaft 86.

The means used to generate the friction torque applied to sleeve member 98 on the one hand and the resilient returning means urging the pinion 94 out of toothed wheel 112 will be now described with reference to FIGS. 7 to 12.

In order to generate the friction torque applied to sleeve member 98 two washer- like rings 116 and 117 have been slipped on said sleeve member. These rings which are similar to those shown in plan view on FIG. 4 comprise a central cut out portion comprising a rectilinear edge cooperating with a flat surface 120 machined on sleeve member 98 with a view to permitting the rings 116 and 117 to be rotatably driven by said sleeve member. Ring 116 is in abutment against a snap ring 124 inserted in a groove provided in sleeve member 98. Ring 117 is applied on the lateral portion of a rubber O-ring 126 extending out of an annular housing 128 in engagement with a shoulder 130 on sleeve member 98. Between rings 116 and 117 is located a friction plate forming unit comprising two annular elements 132 and 133.

Elements 132 and 133 comprise diametrally opposed lugs 134 of semi-cylindrical shape, constituting half shells as shown in FIG. 11. The shells of the annular element 132 have their concavities located in front of the concavities of element 133 so that they may receive finger-like, substantially cylindrical extensions 136 of a fork generally designated by reference numeral 138.

Fork 138 is slidably mounted about a pin 140 fastened to the starter drive body 80, pin 140 passing through a slot 142 which is open in the present example.

Upon fork 138 are acting resilient return means for the unit comprising the sleeve member, the free wheel and the pinion. In the present embodiment said returning means consist of a spring 144. This spring 144, shown in perspective view in FIG. 12, is made of a steel wire the ends of which 145, 146 take support on the inner wall of body while its median portion 147 encompasses the lever forming portion of fork 138. As shown in FIG. 9, the turns of springs 144 provide a good resilient contact between fork 138 and the walls of body 80; thus are avoided the lateral movements of the fork.

The operation of the device which has just been described is similar to the one of the device described with reference to FIGS. 1 to 3.

The device according to the embodiment of FIGS. 7 to 12 presents many advantages from a technical point of view resulting from the suppression or.compensation of the clearances between co-operating elements of the starter drive. I

The provision of shells 134 on the plates 132-134 resiliently urged one toward the other by the O-ring 126 permits a perfect cooperation with compensation of the play between the finger-like extensions 136 and the plates 132 and 133. With this arrangement, as soon as the rotor 86 of the starting motor has been energized, plates 132 and 133 slide with a given friction effect on rings 116117 without being driven in rotation by the latter and it results therefrom that the unit comprising pinion 94, free wheel 102 and sleeve member 98 is immediately axially driven in a direction corresponding to the engagement of pinion 94 into toothed wheel 112. Pinion 94 engages toothed wheel 112 with a rotary speed which is substantially less than if plates 132-133 had been capable of a certain angular motion.

An important improvement is also obtained because of the use of the rubber-ring 126 which is exactly received by housing 128 thus avoiding an extrusion of the elastomeric matter toward the outside of said housing. In efiect, the outwardly portion of the rubber ring 126 is applied upon friction ring 118 and the friction forces applied by the two rings 116-117 upon plate 132-133 are uniformly distributed, the friction torque being thus constant whatever the angular position of the sleeve member with respect to plate 132-133 may be.

In FIGS.v 13 to 15 has been represented still another embodiment of the invention according to which the starter drive comprises a body 150 including a stator 152 in which is rotated a rotor 154 comprising a shaft 156 on which is slidably and rotatably mounted a unit comprising a pinion 158, a free wheel 160 and a threaded sleeve member 162. The splines of the sleeve member 162 cooperate with corresponding long pitch splines of shaft 166. Upon helical motion of the above mentioned unit, pinion 168 engages a toothed wheel 164 driving in rotation an internal combustion engine. At the end of its stroke pinion 168 is brought in abutment against a ring 166 fixed to shaft 156.

Sleeve member 162 passes through a transversal plate 168 solid with body 150. A compression spring 170 is slipped on sleeve member 162, said spring takes support on plate 168 and on a ring 172 which is urged toward the lateral face of a friction plate 174 which is in contact by its other face with a ring 173, the latter being in abutment against a snap ring 176 inserted in a groove provided in sleeve member 162. Rings 172 and 173 are similar to rings 116417 of the embodiment of FIGS, 1 to 11, they cooperate with a flat surface 178 machined on the sleeve member 162 with which they are driven in rotation.

Friction plate 174 is provided with diametrically opposed lugs 180 provided with notches cooperating with longitudinal ribs 182 provided on the inner walls of body 150 parallel to the axis of the shaft of rotor 156. With such an arrangement plate 174 is capable of axial displacements whereas its rotation is forbidden.

In the device that has just been described with reference to FIGS. 13 to 15, the means that are used to apply a friction torque to sleeve member 162 consist of a plurality of parts comprising rings 172-173 and plate 174. Rings 172-173 are urged against plate 174 under the action of the spring 170 which also plays the role of pinion returning means.

The strength of the compression spring 170 is of course carefully calculated as well as the values and the nature of the surfaces of contact between the rings and the plate upon which they are biased by the spring.

The operation of the device of FIGS. 13 to 15 is similar to the one of the other devices which have been described hereinabove.

What is claimed is:

1. A starter drive for starting an internal combustion engine comprising a driving motor having a shaft, and a body, a sleeve member threaded on said shaft, a driving pinion adapted to mesh with an engine flywheel, a unidirectional clutch arranged to transmit torque from said sleeve member to said pinion, resilient returning means biasing said pinion, clutch and sleeve member axially away from said toothed wheel, friction means acting upon said sleeve member to oppose rotation of said sleeve member with said shaft, the torque applied by said friction means to said sleeve member being large enough to cause said pinion to be maintained in meshed engagement with said toothed wheel even when said clutch is in its de-clutched state.

2. A starter drive as claimed in claim 1 wherein said friction means acting upon said sleeve member comprise of at least one non-rotatable plate means resiliently in friction engagement with at least one lining-forming washer rotatable with said sleeve member.

3. A starter drive as claimed in claim 2 wherein said resilient returning means comprises a helical compression spring urging said pinion away from said toothed wheel.

4. A starter drive as claimed in claim 2 wherein said resilient returning means comprise a resiliently biased fork carrying said non-rotatable plate means.

5. A starter drive as claimed in claim 4 wherein said plate means comprise two friction plates slipped on said sleeve member, said friction plates comprising diametrally opposed half shells adapted to cooperate with finger-like extensions of said fork.

6. A starter drive as claimed in claim 5 wherein said two friction plates are squeezed between two washers rotatable with said sleeve member said Washers being urged one toward the other by resiliently compressed means.

7. A starter drive as claimed in claim 6 wherein said resiliently compressed means comprises an O-ring located in an annular housing the bottom of which takes support upon a shoulder provided on said sleeve member.

8. A starter drive as claimed in claim 4 wherein said fork is rocked about a pin fixed to the body of said motor passing through a slot made in the lever forming part of said fork.

9. A starter drive as claimed in claim 1 wherein said unidirectional clutch comprises two race-forming coaxial elements solid with said pinion and said sleeve member respectively, roller means between said elements and a coaxial compressing spring urging the two elements away from one another.

10. A starter drive as claimed in claim 1 wherein said friction means comprise a stop forming snap ring on said sleeve member, a first washer rotatable with said sleeve member engaging said snap ring, a slidable but non rotatable plate in friction engagement by one of its faces with said first washer, a second washer rotatable with said sleeve member in friction engagement with the other face of said plate and a compression spring taking support on a part solid with a portion of the body of said motor to urge said second washer toward said plate.

11. A starter drive as claimed in claim 10 wherein said plate comprises radially extending lugs cooperating with the inner walls of the body of said motor thereby preventing the rotation'of said plate whereas the latter is freely .slidable in said body.

12. A starter drive as claimed in claim 11 wherein said' plate comprises two lugs diametrally opposed provided with notches cooperating with axially extending ribs provided on the inner wall of the body of said motor.

References Cited by the Examiner UNITED STATES PATENTS 1,815,047 7/1931 Burton 747 MILTON KAUFMAN, Primary Examiner.

Claims (1)

1. A STARTER DRIVE FOR STARTING AN INTERNAL COMBUSTION ENGINE COMPRISING A DRIVING MOTOR HAVING A SHAFT, AND A BODY, A SLEEVE MEMBER THREADED ON SAID SHAFT, A DRIVING PINION ADAPTED TO MESH WITH AN ENGINE FLYWHEEL, A UNIDIRECTIONAL CLUTCH ARRANGED TO TRANSMIT TORQUE FROM SAID SLEEVE MEMBER TO SAID PINION, RESILIENT RETURNING MEANS BIASING SAID PINION, CLUTCH AND SLEEVE MEMBER AXIALLY AWAY FROM SAID TOOTHED WHEEL, FRICTION MEANS ACTING UPON SAID SLEEVE MEMBER TO OPPOSE ROTATION OF SAID SLEEVE MEMBER WITH SAID SHAFT, THE TORQUE APPLIED BY SAID FRICTION MEANS TO SAID SLEEVE MEMBER BEING LARGE ENOUGH TO CAUSE SAID PINION TO BE MAINTAINED IN MESHED ENGAGEMENT WITH SAID TOOTHED WHEEL EVEN WHEN SAID CLUTCH IS IN ITS DE-CLUTCHED STATE.

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