FIELD OF INVENTION:

The invention relates to a starter motor of a vehicle.

BACKGROUND OF THE INVENTION:

In a typical electric starter motor for starting a vehicle engine, there is a pinion assembly that is moved into an engagement position on the engine flywheel. The pinion assembly typically moves within a housing on the end of the starter motor housing. A portion of this pinion assembly housing exposes the pinion gear to the flywheel. The engine flywheel extends into this portion, making it possible for the pinion gear to be moved into a position to engage the flywheel.

The opening in the pinion assembly housing for the flywheel provides a clear path for water and dust to the interiors of the starter motor. Especially if the water contains mud particles, the pinion may get jammed leading to locking of the armature of the starter motor. This may result in drawing of high current by the armature and the armature may get burnt in the process.

The contaminating material enters through the open space between the pinion assembly and the housing of the starter motor.

OBJECT OF THE INVENTION:

The object of this invention is to provide a sealing ring which prevents the entry of dust, muddy water into the starter motor thereby increasing the life of the starter motor.

ADVANTAGES OF THE INVENTION:

The invention provides a cost effective design to avoid wear out of the starter motor. There are no design changes required for any existing components of the starter motor.

BRIEF DESCRIPTION OF THE DRAWINGS:-

FIG. 1 shows a schematic of the invention where the pinion assembly has moved forward FIG. 2 shows a schematic of the invention where the pinion assembly has retracted

DETAILED DESCRITPION OF THE INVENTION:
The present invention is described in the preferred embodiment as follows:-
Shown in fig. 1 is a starter motor. The starter motor 10 comprises an armature which is not shown in fig. 1, a housing 12, a shaft 14, a pinion assembly 16 and a sealing ring 18.

The pinion assembly comprises a pinion gear and a clutch mechanism.

The pinion assembly 16 is fixed to the shaft 14 of the starter the motor 10. An actuator which is not shown in fig., when actuated, moves a lever which thrusts the pinion assembly 16 towards the end of the shaft 14, the end being away from the armature. This position of the pinion assembly 16 is shown in the figure 1. The pinion assembly 16 when thrust towards the end of the shaft 10, gets engaged with a flywheel which is not shown. When the starter motor 10 is activated, the shaft 14 starts rotating, thus rotating the pinion assembly. As the pinion assembly 16 is engaged in this position with a flywheel of the vehicle, the flywheel starts rotating. When the flywheel reaches a predetermined speed, the injection and ignition of the fuel take place in the engine which is not shown in the figure. The injection and ignition of the fuel may be controlled by an electronic control unit which is not shown in the figure.

The starter motor 10 supports the rotation of the flywheel till the engine sustains the rotation on its own. Once the flywheel sustains on its own the pinion assembly 16 is retracted back toward the armature as shown in fig. 2. This movement disengages the pinion assembly from the flywheel.

The sealing ring 18 is introduced on a pinion groove on the shaft 14, which seals shaft 14 from the housing 12. The sealing ring 18 is relieved from the housing 12 when the pinion assembly 16 moves forward to engage the flywheel. The sealing ring 18 rotates along with the pinion assembly 16 when the pinion is engaged with the flywheel. When the pinion assembly retracts back, the sealing ring 18 rests against the housing 12. At the pinion rest position, i.e. when the pinion assembly 16 is retracted, the sealing ring 18 acts as a dust cap and prevents the mud water/dust from entering into the starter motor.

The sealing ring 18 may be made of rubber or silicon. The inner diameter of the sealing ring 18 may be dependant on the recommended stretch and the diameter of the shaft 14. The thickness of the sealing ring 18 is selected to match the fitness of the shaft face to the pinion face. The outer diameter of the sealing ring 18 is appropriately selected based on the opening diameter of the shaft 14.

WE CLAIM:

1. A starter motor (10) comprising an armature in a housing (12), a shaft (14), a pinion assembly (16) and a sealing ring (18), the said sealing ring (18) adapted to rest against the housing (12) when the pinion assembly (16) is disengaged from a flywheel thereby sealing the gap between the shaft (14) and the housing (12) adapted to be released from its rest and adapted to rotate along with the pinion assembly (16) when the pinion assembly (16) is engaged with the said flywheel.

2. A starter motor (10) according to claim 1 wherein the sealing ring (18) is placed in a groove on the shaft (14).

3. A starter motor (10) according to claim 1 wherein the sealing ring (18) is made of rubber.

4. A starter motor (10) according to claim 1 wherein the sealing ring (18) is made of silicon