WO2000026533A1

WO2000026533A1 - Engine starter having an axially stationary overrun clutch

Info

Publication number: WO2000026533A1
Application number: PCT/US1999/025610
Authority: WO
Inventors: Dave Fulton; David Durant; Scott Stiffler
Original assignee: Delco Remy America, Inc.
Priority date: 1998-11-03
Filing date: 1999-11-01
Publication date: 2000-05-11

Abstract

An engine starter having an axially stationary overrun clutch comprises an electrical motor having an armature shaft with a central gear formed thereon. The central gear engages a reduction gear unit having a plurality of planetary gears and an orbital gear. The planet gears are supported by gear pins fixedly secured to a clutch shell of an overrun clutch. The overrun clutch further includes a clutch inner having two sides contained within the clutch shell. One side of the clutch inner includes an armature joint for receiving an end of the armature shaft. An overrun shaft extends from another side of the clutch inner coaxial with the armature shaft. The short overrun shaft includes a helical spline gear formed on an outer shaft surface. A stop bolt extends coaxially from the short overrun shaft. A drive shaft comprising a cylinder with an inner circumference having helical splines is slidably joined to the short overrun shaft and the stop bolt. A shift lever having one end cooperating with a solenoid and another end engaging the drive shaft is capable of sliding the drive shaft in a forward direction along the overrun shaft and stop bolt. Sliding movement of the drive shaft along the helical spline gear imparts axial and rotational movement to the drive shaft relative to the clutch inner. A pinion is disposed upon the drive shaft for engagement with an engine ring gear when the drive shaft is moved to a forward position.

Description

ENGINE STARTER HAVING AN AXIALLY

STATIONARY OVERRUN CLUTCH

Background of the Invention

1. Field of the Invention:

The present invention relates to the field of vehicular starters and more particularly to

non-coaxial vehicular starters having an axially stationary overrun clutch to reduce pinion

engagement inertia and thereby reduce the amount of force required from a starter solenoid.

2. Description of the Related Art:

Conventional prior art automotive engine starters comprise a shift lever having two ends,

one end connected to a solenoid plunger rod and the other end connected to a pinion drive shaft.

The plunger rod is carried within a solenoid plunger and extends from the solenoid plunger to

contact the shift lever. A jump spring biases the rod to move with the plunger. Upon excitation

of the solenoid, the plunger moves in a linear direction to reduce a magnetic air gap within the

plunger. As the plunger moves, it takes the plunger rod with it and causes the shift lever to rotate

about a pivot point. Rotation of the lever about the pivot point causes the lever to move the drive

shaft in a linear direction, opposite the direction of the plunger.

The drive shaft is generally connected to an overrun clutch and a pinion. When the shift

lever imparts linear movement to the drive shaft, the overrun clutch and pinion also move

linearly toward an engine flywheel ring gear. The linear movement of the pinion toward the ring

gear generally causes the pinion to mesh with the ring gear. However, if the teeth of the pinion

do not meet the spaces of the ring gear, an abutment will result between the teeth of the pinion

and the teeth of the ring gear. This abutment prevents the pinion from meshing with the ring gear

and restricts further movement of the pinion toward the ring gear. Restriction of pinion movement also restricts movement of the shift lever and plunger rod. However, movement of

the plunger is not prohibited as the plunger compresses the jump spring and continues linear

movement toward reduction of the magnetic air gap.

When the plunger is fully drawn into the solenoid, an electric motor switch is activated.

Rotation of the electric motor transmits rotational power to the drive shaft and pinion through

a reduction gear unit. If an abutment exists between the pinion and ring gear, rotation of the

pinion will release the abutment, and the linear force applied to the plunger rod and shift lever

by the compressed jump spring will accelerate the pinion into mesh with the ring gear. Rotation

of the pinion in mesh with the ring gear will transmit rotational force to a crankshaft and start the

automobile engine.

The above arrangement in the conventional starter is problematic because a relatively

large solenoid is required to insure proper engagement of the pinion with the ring gear. A

smaller solenoid is desirable to reduce the overall size and weight of the starter motor. By

reducing the overall size and weight of the starter motor, manufacturing costs for the starter

motor will be decreased and the starter motor may be used in a wider variety of engines.

The main factors influencing solenoid size are the stroke distance of the plunger, and the

return spring forces that must be overcome over that distance to bring the pinion into engagement

with the ring gear. Particularly, the force required from the jump spring is an important factor

in determining solenoid size. The jump spring must provide sufficient force to accelerate the

pinion into engagement with the ring gear following an abutment. Since the acceleration

required to speed the pinion into mesh with the ring gear is a constant, the force required from

the jump spring is proportional to the mass of materials translated by the jump spring (i.e., f=ma).

In the above described conventional starter arrangement, this mass includes the drive shaft, pinion and overrun clutch. This relatively large mass requires a relatively large force from the

jump spring, and therefore a relatively large solenoid is required to bring the pinion into

engagement with the ring gear.

Accordingly, reducing the mass which the solenoid jump spring must accelerate into

engagement with the ring gear will reduce the force required from the jump spring, and thereby

reduce the overall size of the solenoid. To reduce this mass, elements formerly carried by the

axially moveable drive shaft may be relocated to other parts of the starter. For example, several

starter motor designs include an axially stationary overrun clutch that is not moved by the shift

lever. While these designs have reduced the force required from the solenoid jump spring, and

have thus reduced the required size of the solenoid, other portions of the starter motor have been

enlarged to facilitate relocation of the overrun clutch, or have required several additional parts,

thus increasing the cost and difficulty of manufacturing the starter.

U.S. Patent Nos. 5,156,057, issued to Isozumi, and U.S. Patent No. 5,317,933, issued to

Rometsch each disclose a starter motor with an axially stationary overrun clutch. An axially

stationary overrun clutch may comprise a clutch inner member having a helical spline gear

formed its inner cylindrical surface. The helical spline gear engages complementary helical

splines formed on the outer circumference of the drive shaft. Axial movement is imparted to the

drive shaft through a solenoid operated shift lever. Although the clutch rotates with the drive

shaft, it does not move in the axial direction with the drive shaft and pinion, and thus, less force

is required by the solenoid jump spring to bring the pinion into engagement with the ring gear.

Nevertheless, these starter motors each require additional parts within the starter motor to

incorporate the axially stationary overrun clutch. Additionally, problems have arisen in the

manufacture of the above-described starter arrangement because it is difficult to provide adequately sized helical splines on the relatively narrow interior cylindrical surface of the clutch

inner. Furthermore, the shift lever's access to the drive shaft is hampered when the drive shaft

must pass through the interior of the clutch inner.

Accordingly, it is an object of the present invention to provide a starter having an axially

stationary overrun clutch which requires a minimal number of additional parts so that the starter

motor may retain a compact and inexpensive design.

It is an another object of the present invention to provide a starter motor having an axially

stationary overrun clutch that does not have helical splines on an interior cylindrical surface of

the clutch inner, thereby removing difficulty in the manufacture of the overrun clutch.

Still another object of the present invention is the design of a starter which meets the

above objectives and still provides easy access of the shift lever to the drive shaft.

Summary of the Invention

The present invention realizes advantages over prior art engine starters because the

present invention reduces the amount of force required from the solenoid jump spring, is compact

in design, and is easy to manufacture. As compared to conventional engine starters, the solenoid

jump spring of the present invention is not required to accelerate as much mass to move the

pinion gear into engagement with the ring gear in the case of an abutment, because only a hollow

drive shaft and the pinion are shifted in the axial direction by the solenoid of the present

invention. Therefore, the present invention may utilize a smaller solenoid than that found in

many conventional starters, thereby facilitating use of the starter in more compact engine

compartments. Furthermore, the starter according to the present invention provides for helical

splines on the interior of the drive shaft, rather than the exterior, thus allowing for easy access to the drive shaft by the shift lever, and limiting the difficulty of manufacture of the engine

starter.

Accordingly, an improved starter motor comprises an electrical motor with an armature

shaft that rotates to provide rotational force about an axis of rotation when electrical energy is

applied to the motor. The armature shaft of the improved starter motor engages a gear means

which transmits rotational force from the armature shaft to other parts at increased mechanical

advantage.

The starter motor further comprises an overrun clutch having an outer clutch member

which engages said gear means. The overrun clutch also includes an inner clutch member

secured to an overrun shaft having a helical spline gear formed on its outer circumference.

Rotation of the armature shaft in one direction turns the gear means and thereby rotates the outer

clutch member about the axis of rotation. Rotation of the outer clutch member drives the inner

clutch member when the inner clutch member is static or is not rotating as fast as the outer clutch

member, and thereby transmits rotational force to the overrun shaft. Upon starting of the engine,

the overrun shaft and connected inner clutch member may be turned faster than the driving outer

clutch member. When this occurs, only a negligible amount of rotational force is transmitted

back to the outer clutch member and the armature is thereby protected from excessive speeds.

The starter motor further comprises a drive shaft having two ends. One end of the drive

shaft has an inner circumferential wall which slidably engages the helical spline gear on the outer

circumference of the overrun shaft. Engagement of the drive shaft with the helical spline gear

of the overrun shaft causes the drive shaft to rotate with the overrun shaft and allows the drive

shaft to move linearly with respect to the overrun shaft along the axis of rotation. Linear

movement of the drive shaft with respect to the overrun shaft is effected by a solenoid and solenoid plunger that moves in a linear direction when electrical energy is applied to the

solenoid.

A pinion gear is formed on another end of the drive shaft. The pinion gear is adapted to

engage a flywheel ring gear of an engine when the drive shaft is moved linearly away from the

overrun shaft. A lever means interconnects the solenoid plunger and the drive shaft. The lever

means moves the drive shaft in a linear direction toward the ring gear when electrical energy is

applied to the solenoid and also moves the drive shaft away from the ring gear when electrical

energy is removed form the solenoid.

Brief Description of the Drawings

FIG. 1 is a longitudinal cross sectional view of an engine starter which constitutes a first

embodiment of this invention;

FIG. 2 shows an enlarged longitudinal cross sectional view of the engine starter of FIG.

i;

FIG. 3 shows a longitudinal cross sectional view of an alternative embodiment of the

invention having a removable pinion.

Description of the Preferred Embodiments

As shown in FIG. 1, a non-coaxial engine starter 10 of one embodiment of the present

invention comprises a motor 12 situated within a metallic starter housing 14. Motor 12 includes

stator windings 16 and an armature shaft 18 having a rear end 20 and a front end 22. The rear

end 20 of armature shaft 18 is supported by a rear bearing 24 supported by housing 14. The front

end 22 of armature shaft 18 is supported by a bushing 34 and includes a central sun gear 26 for engaging a planetary gear system 28 and an armature tip 30 which is supported by an inner clutch

bushing 32.

Planetary gear system 28 comprises central sun gear 26, three planet gears 36 which mesh

with sun gear 26, and a planet orbital gear 38. Planet orbital gear 38 is fixed within housing 14

and completely surrounds planet gears 36 in an inter-engaging relationship between the teeth of

orbital gear 38 and the teeth of planet gears 36. Each planet gear 36 is rotatably supported by

a planet gear pin 37 mounted to and axially extending from an overrun clutch 40.

Overrun clutch 40 comprises a cylindrical clutch shell 42 having an outer cylindrical wall

44 and a flat circular face 46. The three planet gear pins 37 are embedded in the flat circular face

46 and perpendicularly extend from the face 46 parallel to armature shaft 18. The flat circular

face 46 includes an armature hole 47 or passage in the center of the face for receiving armature

tip 30. A cylindrical clutch inner member 48 is disposed within the clutch shell 42. Clutch inner

48 includes an armature receiving recess 53 which holds clutch bushing 32 and receives armature

tip 30.

A roller and spring mechanism 50, as is well known in the art, is situated between clutch

shell 42 and clutch inner 48. The roller and spring mechanism 50 allows rotation of clutch inner

48 in a clockwise direction relative to clutch shell 42 as viewed from a drive shaft end 84 of the

non-coaxial engine starter 10. The roller and spring mechanism 50 also prevents

counterclockwise rotation of clutch inner 48 relative to clutch shell 42 as viewed from the drive

shaft end 84 of the non-coaxial engine starter 10.

A short overrun shaft 52 is integral with clutch inner 48 and extends from clutch inner

48 coaxially with armature shaft 18 of motor 12. Short overrun shaft 52 is cylindrical in shape

and includes a helical spline gear 54 on an outer shaft surface. Helical spline gear 54 has a chamfer 55 at the end of short overrun shaft 52. A shaft bore 56 for receiving a stop bolt 58 is

formed within short overrun shaft 52 along a central axis of clutch inner 48. Stop bolt 58

includes a pointed tip 60 and an adjacent cylindrical leg portion 62. Both the tip 60 and leg

portion 62 of stop bolt 58 are fixedly secured within the shaft bore 56 of clutch inner 48 to affix

the stop bolt 58 to the clutch inner 48. Stop bolt 58 also includes a body portion 64 adjacent to

leg portion 62, the body portion 64 being situated outside of shaft bore 56. Stop bolt 58 further

includes a flanged head 66 positioned next to body portion 64 on an opposite end of stop bolt 58

from the tip 60.

Referring now to FIG. 2, a drive shaft 67 slidably engages short overrun shaft 52 and stop

bolt 58. The drive shaft 67 comprises a hollow cylinder having an inner circumference 68 that

fits over short overrun shaft 52. Drive shaft 67 further comprises an outer circumferential wall

63, a pinion end 84, and a lever end 70. Helical splines 65 are formed on the inner circumference

68 of drive shaft 67 at the lever end 70. These helical splines 65 engage the helical spline gear

54 formed on the exterior of short overrun shaft 52. Sliding movement of drive shaft 67 along

helical spline gear 54 is possible until the inner end surface 100 of inner boss 82 engages flanged

head 66. Helical splines 65 and 54 permit rotational and forward movement of drive shaft 67

relative to clutch inner 48.

The inner circumference 68 of drive shaft 67 narrows past the helical splines 65 to form

an inner boss 82 near the center of the drive shaft 67. Inner boss 82 fits around the body portion

64 of stop bolt 58 and is dimensioned to allow drive shaft 67 to slide along stop bolt 58. Drive

shaft 67 is only allowed to slide along stop bolt 58 for the length of body portion 64 since inner

boss 82 of drive shaft 67 is contained between the helical spline gear 54 and the flanged head 66

of stop bolt 58. A cylindrical channel 101 is axially formed at the pinion end 84 of drive shaft 67 to provide clearance for the flanged head 66 of stop bolt 58 when drive shaft 67 slides along

body portion 64.

The pinion end 84 of drive shaft 67 further includes a pinion gear 86 formed thereon for

engagement with an engine flywheel ring gear 88 (shown in dotted lines). Pinion 86 may be

integral the drive shaft 67 as shown in FIG. 1 or may be connected to the drive shaft 67 by

splines, screws, threads and/or other connection means as known in the art. A drive shaft bearing

89 mounted in housing 14 supports drive shaft 67 near pinion 86.

A lever-retaining collar 72 is positioned upon the outer circumferential wall 63 of drive

shaft 67 near lever end 70. The lever retaining collar 72 includes two grooves 74-75 in which

are mounted a pair of annular flanges 76-77. Each flange 76-77 encircles drive shaft 67 at an

outside edge of a groove.

The starter motor further comprises a shift lever 80 having a fork end 98 and a solenoid

end 85. The fork end 98 of shift lever 80 has two tines 95 which extend over and loosely

embrace the outer circumferential wall 63 of drive shaft 67 between the two flanges 76-77. The

tines 95 include end knobs 87 to prevent the tines 95 from losing engagement with drive shaft

67 upon pivoting of the shift lever 80. The shift lever 80 further includes a central pivot elbow

96 above the fork end 98 of lever 80. Pivot elbow 96 is situated in a lever seat within housing

14 and acts as a pivot point for the lever 80. A Y-shaped rod seat 93 is positioned upon the

solenoid end 85 of shift lever 80. The rod seat 93 engages a plunger rod 92 of a solenoid 90.

Solenoid 90 comprises a magnetic air gap 94, a plunger 91, a plunger rod 92, a return

spring 97 and a jump spring 99. Return spring 97 biases plunger 91 away from magnetic air gap

94 toward a forward position in solenoid 90. Plunger rod 92 is carried within plunger 91 and

extends from plunger 91 to engage shift lever 80. Plunger rod 92 is parallel to, but non-coaxial with armature shaft 18. Plunger rod 92 is biased backwardly within plunger 91, encouraging

plunger rod 92 to remain stationary within plunger 91 when plunger 91 is drawn backwardly into

solenoid 90 upon solenoid excitation.

With reference to FIGS. 1 and 2, operation of the non-coaxial engine starter 10 is now

described. When an ignition key of a motor vehicle is turned to start an engine, solenoid 90 is

excited, and plunger rod 92 is drawn toward a backward position within solenoid 90 to reduce

the magnetic air gap, thus pivoting shift lever 80 about pivot elbow 96 in a counterclockwise

manner. The counterclockwise pivot of shift lever 80 causes the tines 95 on the fork end 98 of

shift lever 80 to press against the flange 76 on the drive shaft 67 and move the drive shaft 67 and

pinion 86 in a forward direction toward the engine ring gear 88.

As shift lever 80 presses drive shaft 67 forward, drive shaft 67 and pinion 86 are directed

toward the engine ring gear 88. Engagement of the outer circumferential wall 63 of drive shaft

67 with bearing 89, and engagement of inner boss 82 with body portion 64 of stop bolt 58,

provides support and direction for the drive shaft as it moves within the housing. Pinion 86

movement in a forward direction toward the engine ring gear 88 causes the helical splines 65 on

the inner circumference 68 of drive shaft 67 to interact with the helical spline gear 54 and impart

rotational movement to the drive shaft 67 and pinion 86. The forward movement of pinion 86

causes the teeth of pinion 86 to engage the spaces of ring gear 88 when the shift lever 80 reaches

its full pivot point. Stop bolt 58 limits the distance that the drive shaft 67 may travel along the

short overrun shaft 52 and thereby assists with proper engagement of the pinion 86 and engine

Occasionally, the teeth of pinion 86 will abut the teeth of ring gear 88, preventing the

teeth of pinion 86 and the teeth of ring gear 88 from meshing together. Abutment of the teeth of pinion 86 against the teeth of ring gear 88 restricts further movement of the pinion 86 toward

the ring gear 88, thereby restricting movement of shift lever 80 and plunger rod 92. Movement

of plunger 91 is not prohibited by the abutment of the teeth, as plunger 91 will continue to move

backwardly into magnetic air gap 94 despite the abutment, and jump spring 99 will be

compressed against plunger rod 92.

When plunger 91 is fully drawn into the solenoid, an electric motor switch is activated,

motor 12 is energized, and armature shaft 18 is caused to rotate. Rotation of armature shaft 18

spins sun gear 26 which results in rotational movement of planet gears 36 around the stationary

planet orbital gear 38. As the planet gears 36 rotate, planet gear pins 37 also rotate clutch shell

42 about armature tip 30. In turn, the roller and spring mechanism of the clutch imparts

rotational movement to clutch inner 48 and short overrun shaft 52. Rotation is then imparted to

drive shaft 67 and pinion 86. If an abutment exists between the teeth of pinion 86 and the teeth

of ring gear 88, rotation of the pinion will release the abutment, and the force applied to plunger

rod 92 by compressed jump spring 99 will rotate shift lever 80 and accelerate the teeth of pinion

86 into mesh with the teeth of ring gear 88. Rotation of pinion 86 in mesh with the ring gear 88

will transmit rotational force to a crankshaft to start the motor vehicle engine.

Upon starting of the motor vehicle engine, power to the solenoid is switched off.

Removal of solenoid power causes return spring 97 to returns plunger 91 and plunger rod 92 to

the forward position. As plunger rod 92 returns to its forward position, shift lever 80 is turned

in a clockwise direction, and drive shaft 67 and pinion 86 are retracted from the engine ring gear

88.

Should pinion 86 remain engaged with the engine ring gear 88 for a short time after firing

of the engine, no damage will result to motor 12. After the motor vehicle engine starts, the speed of rotation of the engine ring gear 88 will become so great that it will overtake the speed of

rotation of armature shaft 18. If pinion 86 remains engaged with the engine ring gear 88 during

this time, the excess speed of the engine ring gear 88 and pinion 86 will not be transferred back

to the armature, because of the disengagement of overrun clutch 40. Specifically, when drive

shaft 67 begins to rotate at a speed greater than the speed of armature shaft 18, the roller and

spring mechanism of overrun clutch 40 will disengage to allow the clutch inner 48 to rotate at

the speed of ring gear 88 while the clutch outer will continue to rotate at the speed of armature

shaft 18. In this manner, the motor 12 is protected since it is not required to absorb the excess

speed of the drive shaft 67 upon firing of the engine.

Several alternative embodiments of the present invention are possible as will be

recognized by those skilled in the art. For example, as shown in FIG. 3, the drive shaft 200 may

be modified to include a removable pinion 202. In this embodiment, pinion 202 is keyed to the

drive shaft by horizontal splines 204 on an outer circumference of the pinion which engage

complementary horizontal splines 206 on the inner circumferential wall 208 of the drive shaft.

Other similar keying formations may also be used to connect the pinion to the drive shaft. The

pinion is locked to the drive shaft by a bolt, pressure fit, or other sufficient attachment means.

While the preferred embodiments of the invention have been described herein, it will be

obvious to those of skill in the art that various alterations, changes and modifications may be

made therein without departing from the spirit and scope of the invention. Accordingly, the

appended claims are intended to cover all such changes and modifications as fall within the spirit

and scope of the invention.

Claims

ClaimsWhat is claimed is:

1. An improved starter motor for imparting rotational energy to a flywheel ring gear of a

motor vehicle engine, said starter motor having an electrical motor with an armature shaft

that rotates when electrical energy is applied to the motor to provide rotational force, said

starter motor also having a solenoid with a solenoid plunger that moves in a linear

direction when electrical energy is applied to the solenoid and returns to an initial

position under the bias of a return spring when electrical energy is removed from the

solenoid, wherein the improvement comprises,

(a) gear means for engaging the armature shaft and transmitting rotational force from the

armature shaft at increased mechanical advantage;

(b) overrun clutch means engaging said gear means;

(c) an overrun shaft mounted to said overrun clutch means and extending along and

rotating around the axis of rotation of said overrun clutch means, said overrun shaft having an

outer circumference;

(d) a drive shaft having two ends, a first end slidably engaging said outer circumference

of said overrun shaft so that said drive shaft rotates with said overrun shaft and so that said drive

shaft can move linearly with respect to said overrun drive shaft along said axis of rotation, said

drive shaft having a pinion gear formed on said second end, said pinion gear adapted to engage

the flywheel ring gear when said drive shaft is moved linearly away from said overrun shaft;

(e) a lever means interconnecting the solenoid plunger and said drive shaft, said lever

means for moving said drive shaft in a linear direction toward the ring gear when electrical energy is applied to the solenoid and moving said drive shaft away from the ring gear when

electrical energy is removed from the solenoid.

2. The improved starter motor of claim 1 wherein a helical spline gear is formed on said

outer circumference of said overrun shaft.

3. The improved starter motor of claim 2 wherein said first end of said drive shaft has an

inner circumferential wall, said inner circumferential wall having helical splines formed

thereon.

4. The improved starter motor of claim 1 wherein said gear means further comprises a

planetary gear system, said planetary gear system having a central gear formed on the

armature shaft, a plurality of planet gears spaced around and engaging said central gear,

and a stationary orbital gear surrounding and engaging said plurality of planet gears.

5. The improved starter motor of claim 4 wherein said plurality of planet gears are rotatably

supported by a plurality of gear pins.

6. The improved starter motor of claim 5 wherein said clutch means further comprises a

clutch shell and a clutch inner, said clutch inner located within said clutch shell and said

plurality of gear pins mounted to said clutch shell.

7. The improved starter motor of claim 6 wherein said clutch shell further includes an

armature passage and said clutch inner further includes an armature receiving recess for

supporting the armature shaft.

8. The starter motor of claim 1 wherein said drive shaft further includes a pair of grooves

encircling said drive shaft at said first end, said pair of grooves having a pair of annular

flanges mounted therein.

9. The starter motor of claim 9 wherein said lever means engages said pair of annular

flanges.

10. The improved starter motor of claim 1 wherein said overrun shaft further includes a shaft

bore coaxial with said axis of rotation of said overrun clutch, said shaft bore having a

stop bolt positioned therein which extends from said overrun shaft coaxial with said axis

of rotation of said overrun clutch.

11. The improved starter motor of claim 10 wherein said drive shaft further comprises an

inner circumferential wall, said inner circumferential wall having an inner boss formed

therein coaxial with said axis of rotation of said overrun clutch, said inner boss slidably

engaging said stop bolt.

12. A starter for a motor vehicle comprising:

(a) an electric motor having an armature shaft, said armature shaft having a rear end and

a front end, said armature shaft also having a central gear formed on said front end of said

armature shaft;

(b) a planetary gear system, said planetary gear system comprising a plurality of planet

gears spaced around and engaging said central gear of said armature shaft, said planet

gears being rotatably supported by a plurality of gear pins, and a stationary orbital gear

surrounding said plurality of planet gears and engaging said planet gears;

(c) an overrun clutch positioned adjacent said planetary gear system, said overrun clutch

comprising a clutch shell and a clutch inner member positioned within said shell, said

gear pins being mounted to said shell to cause said shell to rotate as a result of rotation

of said armature shaft and planetary gear system, and means positioned between said

shell and said inner member for imparting rotational forces to said inner member when said inner member is static or rotating no faster than said shell, and for disengaging said

inner member from said shell when said inner member is rotating faster than said shell;

(d) an overrun shaft formed integral with said inner member and extending axially from

said inner member away from said motor such that said overrun shaft is coaxial with said

armature shaft, said overrun shaft having a helical spline gear formed on an outer

cylindrical wall;

(e) a drive shaft having a lever end, said lever end having helical splines slidably

engaging said helical spline gear of said overrun shaft, said drive shaft extending away

from said overrun shaft and said motor such that said drive shaft is coaxial with said

overrun shaft, said drive shaft also having a pinion end, said pinion end having a pinion

gear formed thereon;

(f) a shift lever having a fork end and a solenoid end, said shift lever pivotably mounted

between said fork end and said solenoid end, said fork end of said shift lever engaging

said drive shaft at said lever end, and said solenoid end engaging a solenoid plunger of

a solenoid, said solenoid plunger moving in a linear direction to pivot said shift lever to

cause said pinion gear to engage a flywheel ring gear of an engine when electrical energy

is applied to said solenoid, and to pivot said shift lever in an opposite direction when

electrical energy is removed from said solenoid.

13. The starter motor of claim 12 wherein said shell includes an armature passage and said

inner member includes an armature recess, said armature recess having an inner clutch

bushing for supporting said front end of said armature shaft.

14. The starter motor of claim 12 wherein said drive shaft further includes a pair of grooves

encircling said lever end of said drive shaft, said drive shaft also having and a pair of

annular flanges positioned outside of said pair of grooves.

15. The starter motor of claim 14 wherein said fork end of said shift lever also engages said

pair of annular flanges of said drive shaft.

16. The starter motor of claim 12 wherein said overrun shaft further comprises a shaft bore,

said shaft bore having a stop bolt coaxially positioned therein with said overrun shaft.

17. The starter motor of claim 16 wherein said drive shaft further comprises an inner

circumferential wall, said inner circumferential wall forming a boss and said boss

slidably engaging said stop bolt.

18. The starter motor of claim 12 wherein said drive shaft is supported by a drive shaft

bearing between said pinion and said overrun shaft.

19. The starter motor of claim 12 wherein said pinion is formed integral with said pinion end

of said drive shaft.

20. The starter motor of claim 12 wherein said pinion is removably mounted to said pinion

end of said drive shaft.