Delco Remy America, Inc.

James D Stuber

David A Fulton

A coaxial starter motor assembly that includes a housing. An electrical motor is provided in the housing that has a rotatable armature shaft that is linked with a drive shaft. A pinion assembly is provided that is engageable at one end with the drive shaft and includes a pinion at the other end engageable with a flywheel of an engine. A solenoid assembly is provided for selectively energizing the electrical motor. The solenoid assembly is coaxial with the drive shaft. The solenoid assembly includes a plunger having a bore. The plunger is engageable with the pinion assembly to move the pinion assembly including the pinion into engagement with the flywheel. The plunger is also engageable with a moveable contact to move the moveable contact to electrically connect with a pair of fixed contacts. A return spring is provided that is positioned at least in part within the bore of the plunger of the solenoid assembly for moving the pinion assembly including the pinion away from engagement with the flywheel. The return spring is spaced from the pinion assembly. Energization of the solenoid assembly moves the plunger to move the pinion assembly to engage the pinion with the flywheel. Upon deenergization of the solenoid assembly, the plunger is capable of moving independently of the pinion assembly to thereby break the electrical connection between the moveable contact and the fixed contacts before the return spring moves the pinion assembly to move the pinion away from engagement with the flywheel.

Engagement and disengagement mechanism for a coaxial starter motor assembly

A starter motor assembly is provided. A motor housing encloses an electrical motor having a rotatable armature shaft. A rotatable drive shaft is provided that is engageably linked with the armature shaft. A pinion assembly is also provided, which includes a pinion that is engageable with the drive shaft for turning a flywheel of an engine. A solenoid assembly is provided, which includes a plunger. The plunger, when the solenoid assembly is energized, is moved in an axial direction to close electrical contacts to start the electrical motor and to move the pinion into-engagement with the engine flywheel. Once the engine is cranked and the solenoid is deenergized, a return spring moves the pinion away from engagement with the engine flywheel. The return spring of the present invention moves the pinion without utilizing contact between the spring and the pinion (or any pinion shaft) to move the pinion away from engagement. Thus, the spring may be positioned around the pinion shaft without contacting the pinion shaft.

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Fishers, IN, United States of America

James D Stuber