US3656355A

US3656355A - Engine starter having means for holding same in a cranking position

Info

Publication number: US3656355A
Application number: US22994A
Authority: US
Inventors: Tsuyoshi Matsumoto
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 1969-03-28
Filing date: 1970-03-26
Publication date: 1972-04-18
Anticipated expiration: 1989-04-18

Abstract

An engine starting device is provided with holding means for holding a rotationally driven pinion in engagement with a ring gear of the engine to be started. The holding means comprises a translatable and rotatable barrel member having connected thereto the pinion and a pawl. A detent is slidably mounted in a radial extending hole provided in a fixed support member and cooperates with the pawl to maintain the pinion in mesh with the engine ring gear until the engine is started.

Description

United States Patent Matsumoto 3,656,355 Apr. 18, 1972 ENGINE STARTER HAVING MEANS FOR HOLDING SAME IN A CRANKING POSITION lnventor: Tsuyoshi Matsumoto, l-limeji, Japan 1 Assignee: Mitsubishi Denki Kabushiki Kaisha,

Tokyo, Japan Filed: Mar. 26, 1970 Appl. No.: 22,994

Foreign Application Priority Data Mar. 28, 1969 Japan ..44/27646 U.S. Cl ..74/7 B Int. Cl ....F02n 15/06 Field of Search ..74/7 B, 7 R, 6

{56] References Cited UNITED STATES PATENTS 1,210,028 12/1916 Adams, Jr .J. ..74/7 B X 3,247,727 4/1966 Digby et al. ..74/7 B Primary Examiner-Milton Kaufman Attorney-Robert E. Burns and Emmanuel J. Lobato [57] ABSTRACT An engine starting device is provided with holding means for holding a rotationally driven pinion in engagement with a ring gear of the engine to be started. The holding means comprises a translatable and rotatable barrel member having connected thereto the pinion and a pawl. A detent is slidably mounted in a radial extending hole provided in a fixed support member and cooperates with thepawl to maintain the pinion in mesh with the engine ring gear until the engine is started.

9 Claims, 2 Drawing Figures PATENTEDAPR 18 mm FIG. 1

FIG. 2

ENGINE STARTER HAVING MEANS FOR HOLDING SAME IN A CRANKING POSITION BACKGROUND OF THE INVENTION This invention relates to a starter device for an internal combustion engine, and more particularly to such a device including a starting electric motor to start the associated engine.

There have been already known starter devices including a starting electric motor for automatically driving a pinion involved into mesh with a ring gear on the associated internal combustion engine through the utilization of torque provided by the starting motor for starting the engine. Such starter devices are generally called the Bendix type.

Specifically the invention concerns improvements in the Bendix type of starter devices.

In the Bendix type of starter devices, there may occur the phenomenon that before the associated engine will have been able to start, the pinion comes out of mesh with the ring gear resulting in the difficulty with which the engine is started. This is generally known as the phenomenon of premature disengagement of a pinion. U.S. Pat. No. 2,727,394 issued Dec. 20, I955 to D.L. Hager discloses and claims improved means for preventing a pinion from prematurely disengaging from the associated ring gear.

According to the cited patent, a control nut is threaded on a screw shaft driven by a driving shaft of the starting electric motor and retained in one end of a barrel member having fixed at the other end a pinion. A spring biased detent member is slidably mounted in the control nut for radial movement. The screw shaft is rotated to traverse the control nut thereon to bring the pinion into mesh with a ring gear on the engine. On the other hand, the screw shaft is provided with a recess adapted to receive the detent member when the pinion meshes with the ring gear. The detent member is held in engagement with the recess until the rotational movement of the screw shaft reaches the number of revolutions per unit time with which the engine can be satisfactorily started, or when the engine has been started enough to drive the pinion by the ring gear. Thereafter the detent member is moved away from the driving motor shaft by means of the centrifugal force exerted on the same until it disengages from the recess.

In the arrangement as above described, the engagementof the detent member with the recess serves to maintain the pinion in mesh with the ring gear until the engine is satisfactorily started whereby the pinion is prevented from prematurely disengaging from the ring gear. The arrangement, how ever has various disadvantages. For example, the machining operation of forming the recess on the screw shaft is difiicult to perform. More specifically, the recess is required to be formed on a certain portion of the tooth crest on the screw shaft during the drilling operation and is difficult to perform a and consumes a long time. Also the control nut has the inner surface screw threaded to mesh with the screw shaft and a radial hole adapted to receive the detent member should be opened in a particular bottom land on the inner screw threaded surface of the control nut. The operation of forming such a hole is also difficult to and consumes a long time. Further, the control nut is disposed in the barrel member axially movable with the pinion and operatively associated with the spring biased detent member also axially movable with the pinion. Therefore the parts axially movable with the pinion are complicated in construction so that any one or more of such parts may damage and the resulting started device is deteriorated in capability.

SUMMARY OF THE INVENTION Accordingly it is an object of the invention to provide a new and improved starter device usable with a starting electric motor and which is simple and easy to manufacture, and including axially movable parts assembled into a simplified structure.

The invention accomplishes this object by the provision of a starter device for an internal combustion engine comprising, a

movable barrel member fitted onto a driving shaft for axial movement and provided on the inner peripheral surface with a helical spline through which the same is subject to a force tending to move it axially, a pinion disposed on the outer peripheral surface and engageable by a ring gear on the engine through the axial movement of the barrel member, a pawl member disposed on the outer peripheral surface of the barrel member, a support member rigidly secured on the driving shaft to be axially opposite to the barrel member, and a detent member disposed within the support member for radial movement and engageable by the pawl member when the pinion is in mesh with the ring gear to start the engine by the pinion whereby the detent member prevents the pinion from disengaging from the ring gear.

BRIEF DESCRIPTION OF THE DRAWING The invention will becomr more readily apparent from the following detailed description taken in conjunction with the accompanying drawing in which:

FIG. 1 is a side elevational view, partly in longitudinal sec tion of a starter device constructed in accordance with the principles of the invention and illustrated in its normal or idle position with parts broken away; and

7 FIG. 2 is a view similar to FIG. 1 but illustrating the device in its cranking position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing and FIG. 1 in particular, it is seen that an arrangement disclosed herein comprises a driving shaft generally designated by the reference numeral 1 and forming a part of a rotary shaft of a starting electric motor (not shown). The driving shaft 1 includes a reduced diameter portion 1A, a medium diameter portion 18 and an enlarged diameter portion 1C connected to each other with the en larged diameter portion connected at right-hand end as viewed in FIG. 1 to the electric motor (not shown). The medium diameter shaft portion 1B has a plurality of straight splines 2 axially extending from that end thereof adjacent to the reduced shaft portion 1A toward but clear of the other end. Then a screw sleeve 3 is slidably threaded onto the medium diameter shaft portion 1B by having a plurality of internal longitudinal splines 4 complementary in. configuration to and meshing with the straight splines 2 on the shaft portion 13 whereby the screw sleeve 3 is prevented from rotating about the driving shaft 1.

As best shown in FIG. 2, the screw sleeve 3 is provided on the outer peripheral surface with a helical spline 5. Then a movable driving member in the configuration of a barrel member 6 is fitted onto the screw sleeve 3 for axial and rotational movements relative to the screw sleeve by having a heli cal spline 7 disposed on the inner peripheral surface complementary in configuration to the helical spline 6 and meshing with the latter. The helical splines 5 and 7 mesh with each other and function to generate a force tending to move the movable barrel member 6 axially in the lefthand direction as viewed in FIGS. 1 and 2 in the well known manner during rotational movement of the driving shaft 1.

A pinion 8 is fixedly secured to the movable barrel member 6 on that end portion near the enlarged diameter shaft portion 1C of the outer surface. In the normal or idle position as shownin FIG. 1, the pinion 8 is located at the right (as viewed in FIG. 1) of a ring gear 9 on an internal combustion engine (not shown) to be opposite to the ring gear with a gap formed therebetween. In the cranking operation, the abovementioned force generated through the meshing of the helical splines 5 and 7 acts to move the pinion 8 to its working position illustrated in FIG. 2 where it meshes with the ring gear 9.

As best shown in FIG. 1, the barrel member 6 is provided on that end portion remote from the pinion 8 of the outer peripheral surface or on the left-hand end portion thereof as viewed in FIG. 1 with a pawl member 10 for the purpose as will be apparent hereinafter. The pawl member 10 can be formed by cutting a circumferential groove 11 on the lefthand end portion of the outer peripheral barrel surface. That side wall a of the annular groove 1 1 near the end face of the barrel member 6 constitutes one end face of the annular pawl member 10. The pawl member 10 is tapered from its maximum radial distance from the axis of the driving shaft of d to its minimum radial distance of d, at the end face to form a tilted or inclined face 12 that may be rectilinear or curved, for the purpose as will be apparent hereinafter. It is noted that the pawl member 10 is prevented from contacting the ring gear 9 when the barrel member 6 is moved.

A buffer unit generally designated by the reference numeral 20 is mounted on the medium diameter shaft portion 1B and to the right of the screw sleeve 3. The buffer unit 20 comprises an annular disc 21 fitted onto the medium shaft portion 18 and adjacent to the screw sleeve 3 for axially sliding movement, an annular cover 22 of L-shaped cross section slidably fitted onto the shaft portion to abut against the disc 21, and an annular holding disc 23 fitted onto the shaft portion 1B to be somewhat separated from the cover 22. The holding disc 23 abuts against a shoulder formed between the medium and enlarged shaft portions 18 and 1C respectively and is thereby prevented from moving beyond its position illustrated in FIG. 1 in the right-hand direction as viewed in FIG. 1. The holding disc 23 includes an annular step 24 formed on the intermediate portion thereof and configured to embrace an annular rubber buffer member 25 between the same and the cover More specifically, the buffer member 25 abuts at both ends against the opposite surfaces of the cover and

disc

22 and 23 respectively and on the outer periphery against the inner periphery of the cylindrical cover 22 portion. Then the step 24 on the holding disc 23 holds the adjacent portion of the inner peripheral surface of the bufier member 25. The buffer member 25 is adapted to be compressed in response to a reaction force developed upon the meshing of the pinion 8 with the ring gear 9, that is to say, a force tending to move the disc and

cover

21 and 22 beyond their illustrated positions in the right-hand direction as viewed in FIG. 1 through the screw sleeve 3 thereby to function as buffer means.

In order to limit the movement of the pinion 8 and therefore the movable barrel member 6 in the left-hand direction as viewed in FIG. 1, a detent supporter unit generally designated by the reference numeral 30 is positioned to the left of the ring gear 9 as viewed in FIG. 1 and rigidly mounted on the reduced diameter shaft portion 1A to form a spacing therebetween. The supporter unit 30 comprises an annular, relatively thick support disc 31 including a cylindrical portion on that end portion adjacent the ring gear 9 and tapered toward the other end portion. The support disc 31 includes a hollow portion encircled by a first inner cylindrical surface 32 and a second inner cylindrical surface 33 larger in diameter than and connected through an annular radial surface 34 to the first cylindrical surface 32. The second inner cylindrical surface 34 has a diameter sufficient to receive the barrel member 6. A sleeveshaped spacer 35 is fitted onto the reduced shaft portion 1A between the bottom surface of the support disc 31 and a shoulder formed between the reduced and medium'shaft portions 1A and 1C respectively. A lock nut 36 is screw threaded on the screw threaded, free end portion of the reduced shaft portion 1A to push the bottom surface of the disc 31 against the sleeve-shaped spacer 35 which is, in turn, pushed against the shoulder at the shaft transition from the reduced diameter portion 1A to the medium portion 18 with the result that the support disc 31 is firmly held in place on the driving shaft 1.

The sleeve-shaped spacer 35 has slidably fitted thereon a spring bearing 37 smaller in diameter than and abutting against the end face of the barrel member 6 at the tilted surface 12 terminates. The spring bearing 37 is greater in diameter than the first inner cylindrical surface 32 of the disc 31. A helical spring 38 is disposed around the spacer 35 between the bottom surface of the disc 31 and the spring bearing 37 to be somewhat compressed in its normal or idle position thereby exerting a resilient force upon the barrel member 6 through the spring bearing 37 tending to force the barrel member 6 to abut against the buffer unit 20 along with the screw sleeve 3. During the cranking operation, the abovementioned force developed at the mesh of the helical splines 5 and 7 serves to move the barrel member 6 toward the supporter unit 30 as previously described to additionally compress the helical spring 38. This causes the generation of a reaction force tending to move screw sleeve 3 in the righthand direction as viewed in FIG. 1. The reaction force is accommodated by the buffer unit 20.

As above described, the first inner cylindrical surface 32 of the disc 31 has a diameter smaller than the outside diameter of the spring bearing 37 and the second inner cylindrical surface 33 has a diameter sufficient to receive therein the barrel member 6 containing thereon the pawl 10. In the cranking position as shown in FIG. 2, the barrelmember 6 enters the hollow disc 31 so that the pawl 10 abuts against the second inner cylindrical surface 33 while the spring bearing 37 abuts against the radial surface 34 to limit the maximum axial displacement of the the barrel member 6 to a position wherein the pinion 8 has just been brought into mesh with the ring gear 9 with the compression spring 38 most strongly compressed.

The support disc 31 is provided on the outer cylindrical periphery with holding means for releasably holding the pinion in its cranking position and the holding means comprises a radial hole 41 opening at one end on the second cylindrical surface 33 and closed at the other end by a cover 42 attached to the outer periphery. The radial hole 41 is positioned directly above the circumferential groove 11 on the barrel member 6 when the barrel member is in its cranking position and has a shoulder 43 on the intermediate portion dividing the radial hole 41 into two hole portions with the smaller hole portion opening in the second cylindrical surface 33. Slidably fitted into the hole 41 is a detent member 44 complementary in shape to the hole and being of a hollow type closed at the bottom or inner end 45 projecting beyond the second cylindrical disc surface 33. A compression spring 46 is disposed in the interior of the detent member 44 between the bottom thereof and the cover 42 and cooperates with the shoulder 43 on the hole 41 to bias the detent member 44in its normal extended position as shown in FIG. 1. At that position, the detent member 44 projects beyond the second inner disc surface 33 and is radially spaced from the axis of the driving shaft 1 by a distance of d meeting the relationship d d;, d where d, and d have been previously defined.

Upon starting the associated engine (not shown), the starting motor (not shown) is energized to rotate the screw sleeve 3 to thereby move the barrel member 6 in the lefthand direction as viewed in FIG. 1 while rotating it. During this movement of the barrel member 6, the tilted or inclined surface 12 thereon first abuts against the end face 45 of the detent member 44 to lift or retract the detent member 44 against the action of the spring 46 until the pawl 10 is contacted on its maximum diameter portion by the end face 45. When the barrel member 6 has undergone its maximum axial movement reached its cranking positionas shown in FIG. 2, the detent member 44 rides across the pawl 10 until it falls into the groove 11 on the barrel member 11 6 and engages therewith to releasably lock same in the cranking position.

Under these circumstances, the rotational movement of the driving shaft 1 causes the detent member 44 to' be acted upon centrifugal force tending to move it radially outwardly against the spring 46. However, the spring 46 is pre-selected to hold the detent member 44 at its engaging position where it is located nearer to the axis of the driving shaft than the maximum diameter portion of the pawl 10 until the rotational movement of the driving shaft 1 reaches a predetermined number of rotations per unit time or rotational speed with which the engine is able to start. In other words, the detent member 44 remains engaged with the groove 11 on the barrel member 6 until the driving shaft 1 obtains a preselected speed.

Therefore if the barrel member 6 tends to be returned from its cranking position, as illustrated in FIG. 2, back to its normal position, as illustrated in FIG. 1, before the engine is able to start, then it always strikes against the wall surface 100 positioned to the right of the pawl 10. In this case if the detent member 44 has struck against the wall surface 10a from the righthand side thereof, the latter does not function to lead the detent member 44 to the maximum diameter portion of the pawl 10 because the wall surface 10a extends radially and substantially perpendicularly to the surface of the groove 11. That is, it releasably engages with the barrel member 6 to prevent the barrel member 6 from returning back to its normal posi tion. As a result, the barrel member 6 can be inhibited from being moved from its cranking position toward its original position when the engine is not able to start. Thus it will be appreciated that the detrimental phenomenon that the pinion prematurely disengages from the engine gear is eliminated ensuring that the engine can be started.

After the completion of the engine starting operation, the starting motor decreases in loading to increase the number of rotations per unit time of the driving shaft 1 until it exceeds the predetermined magnitude whereupon the resulting centrifugal force overcomes the biasing force of the spring 46 to permit the detent member 44 to be moved externally of a circle described by the maximum diameter portion of the pawl 10. This eliminates the constraint preventing the barrel member 6 from returning from its cranking position to its original or idle position whereby it returns back to its original position by means of the action of the resilient force accumulated by the compression spring 38.

In summary, the invention comprises a movable barrel member movably disposed on a driving shaft and provided on the inner peripheral surface with a helical spline serving to generate a force for axially moving the same along with the shaft and on the outer peripheral surface with a pawl, and a detent member movably supported by a support unit disposed fixedly on the driving shaft and in axially opposite relationship with the barrel member. This results in several advantages. For example, the position of the pawl is independent of the helical spline on the barrel member and therefore the pawl is not required to be formed on the crest of the helical spline. Also the hole into which is fitted the detent member can be formed independently of the helical spline. Thus both the pawl and the detent hold can readily be formed.

Further since the detent member disposed in the supporter unit fixed on the driving shaft but not on the barrel member, the moving parts involving the barrel member are simplified in construction leading to a decrease in failure of those parts and also to improvements in capability of the resulting device.

I claim:

1. A starter device engageable with a ring gear of an internal combustion engine comprising, in combination: a rotatable driving shaft; a movable barrel member including an inner peripheral surface having disposed thereon a helical spline and an outer peripheral surface, said barrel member being fitted onto said driving shaft for axial movement and subject through said helical spline to a force for axially moving the same; a pinion disposed on said outer peripheral surface of said movable barrel member engageable with said ring gear in response to axial movement of said movable barrel member; a pawl member disposed on said outer peripheral surface of said movable barrel member; supporter means fixedly secured on said driving shaft in axially opposite relationship with respect to said movable barrel member; a detent member disposed in said supporter means for radial movement and upon meshing of said pinion with said ring gear to start the engine, capable of engaging with said pawl member to prevent said pinion from disengaging from said ring gear until the engine is started; and wherein said pawl member has an inclined surface on that side thereof near to said supporter means and an engaging surface on the other side thereof, said inclined surface being operative when said pinion is moved into mesh with said ring gear to lead said detent member to its position where the latter poses said engaging surface, said engaging surface being operative when said pinion tends to move out of engagement with said ring gear during the operation of starting the engine to engage said detent member to thereby prevent axial movement of said pinion.

2. A starter device as claimed in claim 1 wherein said movable barrel member has disposed thereon means defining a circumferential groove having a lateral wall on that side thereof near to said supporter means, said pawl member being fonned in the form of an annulus on the top of said lateral wall and including said inclined surface on that side opposite to said lateral wall,

said lateral wall being operative, when said pinion tends to move out of engagement with said ring gear during the operation of starting the engine, to engage said detent member thereby to prevent said movement of said pinion,

said inclined surface being operative, when said pinion is moved into mesh with said ring gear, to lead saiddetent member to its position where the latter opposes to said lateral wall.

3. A starter device as claimed in claim 1 comprising a compression spring within said supporter means compressable through the movement of said movable barrel member, and

an engaging surface within said supporter means for receivingone end of said compression spring having the other endengaging said movable member.

4. A starter device as claimed in claim 1 comprising a compression spring within said supporter means compressable through the movement of said movable barrel member,

an engaging surface within said supporter means for receiving one end of said compression spring having the other end engaging said movable member, and

another engaging surface for determining a maximum magnitude of movement of said movable barrel member.

5. A starter device as claimed in claim 1 wherein said supporter means include a hollow cylindrical member encircling said driving shaft and having radially extending therethrough a hole in which said detent member is disposed.

6. A starter device as claimed in claim 1 wherein said supporter means include a hollow cylindrical member encircling said driving shaft and having .a hole radially extending therethrough said hole having a shoulder formed on the intermediate portion thereof and said detent member disposed therein, and

a spring disposed in said hole to bias said detent member toward said driving shaft,

said shoulder being operative to maintain said detent member at its predetermined position against the action of said spring.

7. A starter device as claimed in claim 1 wherein said supporter means include a hollow cylindrical member encircling said driving shaft and having ahole radially extending therethrough, said hole having a shoulder formed on the intermediate portion thereof and said detent member disposed therein,

a cover member disposed on the outer peripheral surface of said hollow cylindrical member to close one end of said hole, and

a spring disposed in said hole between said cover and detent members to bias said detent member toward said driving shaft,

8. In a starting device for imparting starting rotation to a driven member; a rotatable input shaft rotationally driven in a given direction during use of the starting device; a driving member having means thereon releasably engageable with the driven member to be rotated; means mounting said driving member on said input shaft for translational movement therealong between an idle position wherein same is out of engagement with the driven member and a cranking position wherein same both releasably engages with the driven member and concurrently rotates with said input shaft to impart starting rotation to the driven member'in response to rotation of said input shaft; and holding means releasably engageable with said driving member when same is in said cranking position for releasably holding said driving member in said cranking position only until the driven member has obtained a predetermined rotational speed comprising a support member connected to said input shaft for rotation therewith, means defining an opening within said support member positioned along and extending transversly to the path of translational move-' ment of said driving member, means defining an annular groove in said driving member and a movable detent member movable mounted within said opening to engage with said anmember out of said path of travel to thereby allow said driving member to move into said cranking position whereupon said spring means biases said detent member into said annular groove.

Claims

2. A starter device as claimed in claim 1 wherein said movable barrel member has disposed thereon means defining a circumferential groove having a lateral wall on that side thereof near to said supporter means, said pawl member being formed in the form of an annulus on the top of said lateral wall and including said inclined surface on that side opposite to said lateral wall, said lateral wall being operative, when said pinion tends to move out of engagement with said ring gear during the operation of starting the engine, to engage said detent member thereby to prevent said movement of said pinion, said inclined surface being operative, when said pinion is moved into mesh with said ring gear, to lead said detent member to its position where the latter opposes to said lateral wall.

3. A starter device as claimed in claim 1 comprising a compression spring within said supporter means compressable through the movement of said movable barrel member, and an engaging surface within said supporter means for receiving one end of said compression spring having the other end engaging said movable member.

4. A starter device as claimed in claim 1 comprising a compression spring within said supporter means compressable through the movement of said movable barrel member, an engaging surface within said supporter means for receiving one end of said compression spring having the other end engaging said movable member, and another engaging surface for determining a maximum magnitude of movement of said movable barrel member.

6. A starter device as claimed in claim 1 wherein said supporter means include a hollow cylindrical member encircling said driving shaft and having a hole radially extending therethrough said hole having a shoulder formed on the intermediate portion thereof and said detent member disposed therein, and a spring disposed in said hole to bias said detent member toward said driving shaft, said shoulder being operative to maintain said detent member at its predetermined position against the action of said spring.

7. A starter device as claimed in claim 1 wherein said supporter means include a hollow cylindrical member encircling said driving shaft and having a hole radially extending therethrough, said hole having a shoulder formed on the intermediate portion thereof and said detent member disposed therein, a cover member disposed on the outer peripheral surface of said hollow cylindrical member to close one end of said hole, and a spring disposed in said hole between said cover and detent members to bias said detent member toward said driving shaft, said shoulder being operative to maintain said detent member at its predetermined position against the action of said spring.

8. In a starting device for imparting starting rotation to a driven member; a rotatable input shaft rotationally driven in a given direction during use of the starting device; a driving member having means thereon releasably engageable with the driven member to be rotated; means mounting said driving member on said input shaft for translational movement therealong between an idle position wherein same is out of engagement with the driven member and a cranking position wherein same both releasably engages with the driven member and concurrently rotates with said input shaft to impart starting rotation to the driven member in response to rotation of said input shaft; and holding means releasably engageable with said driving member when same is in said cranking position for releasably holding said driving member in said cranking position only until the driven member has obtained a predetermined rotational speed comprising a support member connected to said input shaft for rotation therewith, means defining an opening within said support member positioned along and extending transversly to the path of translational movement of said driving member, means defining an annular groove in said driving member and a movable detent member movable mounted within said opening to engage with said annular groove when said driving member is moved into said cranking position.

9. A starter device according to claim 8; including spring means continuously biasing said detent member into said path of travel of said driving member, and wherein said driving member has an inclined leading surface portion adjacent said annular groove engageable with said detent member during movement to said cranking position to move said detent member out of said path of travel to thereby allow said driving member to move into said cranking position whereupon said spring means biases said detent member into said annular groove.