Starter motor casing

A starter assembly has a starter motor with a center casing. A front housing is attached to the center casing and the front housing is adapted to attach the starter assembly to the vehicle. The center casing includes a pilot ring which mates with a groove in the front housing to define a serpentine path between the inside and outside of the starter assembly. The pilot ring is formed at the inside diameter of the center housing to define a dam which prohibits contaminants from entering the center housing.

CROSS-REFERENCE TO RELATED APPLICATIONS

Field

The present disclosure relates to starter assemblies for internal combustion engines. More particularly, the present disclosure relates to starter assemblies having a universal mount having a step shaped pilot surface.

Background

Starter assemblies for internal combustion engines are typically designed to fit a specific engine application. This creates a large number of unique starter assemblies which have the identical motor structure but which are different in the way they are adapted for connection to the specific engine.

Adapting a starter assembly for use with multiple engines or use with an engine other than that for which the starter assembly was originally designed is currently known in the art. Typically, such adaptations are made on automobiles for the aftermarket, for the purposes of racing or for the purposes of replacement of expensive or difficult to locate starters on exotic or antique automobiles. Some known starter assembly adaptation techniques require precision, custom machining work and are thus labor intensive and costly.

Other known designs allow for the changing of the attachment rotational angle by providing an adaptive ring with a plurality of attachment holes by which the adaptive ring can be secured to the starter assembly with attachment bolts. The adaptive ring includes a plurality of discrete sets of position holes which can be used to attach an adapter having a plurality of securing holes using attachment bolts. The adapter further includes mounting holes for securing the adapter to the engine using mounting bolts. This system allows the starter assembly to be attached to the engine in a variety of rotational positions.

The mounting of the various housings, adaptive plates and adaptors usually involves a pilot flange which engages a pilot diameter in the mating component to properly align the two components. The point of attachment of the various components with or without a pilot flange is a potential route of water or contaminants entry which can be detrimental to the internal mechanical and electrical components unless proper handling of the ingested water or contaminants is designed into the components.

SUMMARY

The present disclosure provides a universal mount for a starter assembly which does not involve the use of adaptive plates or adaptors. The starter assembly includes a center housing and a front housing. The center housing defines a plurality of sets of mounting holes for the front housing. By selecting different sets of mounting holes for the front housing, the rotational position of the starter assembly with its solenoid can be adjusted.

The center housing and front housing also define a piloting system which is configured to guide any water or contaminants that may leak past the attachment interface to a position away from the internal mechanical and electrical components of the starter assembly. In addition, the piloting system provides additional support for the starter assembly which lessens the tendency of a gap being formed at the attachment interface.

DETAILED DESCRIPTION

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. There is illustrated inFIG. 1a starter assembly10for an internal combustion engine. Starter assembly10comprises a starter motor12, an electromagnetic plunger14and a front housing16.

Starter motor12comprises a motor housing20, a stator22, a rotor24and a motor shaft26. Motor shaft26is press-fit to rotor24as is known in the art. An end frame28is fixed to the rear portion of motor housing20and a center casing30is fixed to the front portion thereof.

As illustrated inFIG. 3, a plurality of threaded bores32are formed at the front surface of center casing30. Front housing16includes a flange34at the open end thereof for attachment of front housing16to center casing30of starter motor12.

Flange34of front housing16defines a plurality of through holes40which are in a pattern designed to mate with a specific set of threaded bores32. Threaded bores32are designed to define a plurality of sets of patterns that align with the pattern of through holes40in flange34of front housing16. In this manner, front housing16can be mounted in a plurality of rotational positions with respect to starter motor12as illustrated inFIG. 4. Flange34of front housing16also defines a plurality of ear-like fixing portions42projecting radially outward from the outer periphery thereof. Each ear-like fixing portion defines a fastening hole44. Front housing16is fixed to the front surface of center casing30at flange34using a plurality of bolts which extend through the through holes to threadingly engage a respective threaded bore32. As illustrated inFIG. 4, front housing16can be fixed to center casing30at a rotational or angular position with respect to center casing30such that starter assembly10will fit into a specific vehicle application.

Motor housing20, end frame28and center casing30have nearly the same outside diameter D1as illustrated inFIG. 1. Starter assembly10is fixed to a bracket (not shown) of an internal combustion engine (not shown) using a plurality of fastening bolts50which extend through fastening holes44. Fastening holes44are formed on a circumference of a diameter D2to prevent motor housing20from obstructing access to the heads of the plurality of fastening bolts50as illustrated inFIG. 5. In other words, diameter D1is made smaller than the diameter D3of an inscribed circle of the heads of the plurality of fastening bolts50. Accordingly, a fixing tool, such as a socket wrench can have access to the heads of the plurality of fastening bolts50around motor housing20.

End frame28and center casing30each have two pairs of radially projecting fixing portions52and54and they are attached to each other by two fastening bolts56using fixing portions52and54.

Motor shaft26extends through the inside of center casing30and it carries a sun gear60of a planetary gear speed reduction mechanism62that is comprised of planetary gears64and a ring gear66. Planetary gears64are fixed to the rear portion of a drive shaft68and ring gear66is fixed to the inner wall of center casing30.

Drive shaft68is supported at its rear end by center casing30using a rear bearing70and at its front end by front housing16using a front bearing72such that drive shaft68is coaxial with motor shaft26. An overrunning clutch74and a pinion76are carried by drive shaft68such that they slide axially along drive shaft68.

Electromagnetic plunger14is disposed on motor housing20and center casing30. Electromagnetic plunger14comprises an electromagnetic coil80, a plunger82, a rod84, a compression coil spring86, a contact bridge88, and a pair of stationary contacts90and92. Compression coil spring86and rod84are disposed inside electromagnetic coil80. Contact bridge88is fixed to the end of plunger82that projects from electromagnetic coil80to face the pair of stationary contacts90and92.

A lever94is rotatably supported by a pin96. Lever94is fixed at its upper end to a front portion of plunger82. A ring-shaped dust seal98is disposed between flange34and center casing30such that an inner edge of dust seal98contacts the outer periphery of overrunning clutch74thereby keeping dust off the inside of center casing30.

When a starter switch is turned on, electromagnetic coil80is energized to move plunger82together with rod84rearward or to the right inFIG. 1. This causes lever94to rotate about pin96. Therefore, pinion76together with overrunning clutch74are moved along drive shaft68forward or to the left inFIG. 1to engage a ring gear (not shown) of the engine. When plunger82moves to the right as shown inFIG. 1, rod84urges contact bridge against stationary contacts90and92and this closes the power circuit to starter motor12. Accordingly, motor shaft26rotates drive shaft68via sun gear60and planetary gears64of planetary gear speed reduction mechanism62. This rotates the ring gear of the engine and the engine will start.

Referring now toFIG. 2, the mounting system in accordance with the present disclosure is described in more detail. Center casing30defines an inside diameter110and an axially extending flange or pilot ring112which forms an outer groove114. Pilot ring112includes an extension of inside diameter110and it is located on the radially inner portion of the end face of center casing30. Front housing16defines an inside diameter120which is larger than inside diameter110of center casing30. Front housing16also defines an inner groove122which accepts pilot ring112of center casing30. This mounting system creates a serpentine path depicted by arrow126through which any water or contaminants must flow from the environment outside the starter assembly in order to reach the inside chamber of front housing16and/or center casing30. Once any water or contaminants reach the inside of front housing16, the fact that inside diameter120is larger than inside diameter110creates a dam which will have a tendency to direct the water or the contaminants into front housing16and away from the inside chamber of center casing30within which the electrical and mechanical components of starter motor12are located.

Referring now toFIGS. 6A and 6B, a prior art mounting system is compared with the mounting system in accordance with the present disclosure. In the prior art mounting system illustrated inFIG. 6A, because a starter assembly10′ is cantilevered from a front housing16′, the weight of and the vibration of a starter motor12′ will easily create an opening18′ at the top of the interface between front housing16′ and starter motor12′ as illustrated inFIG. 6A. In addition, the movement of starter motor12′ in relation to front housing16′ causes additional stress to a front bearing72′ in front housing16′.

In the mounting system of the present disclosure as illustrated inFIG. 6B, the engagement between pilot ring112and inner groove122provide support for starter motor12and thus a more robust connection between starter motor12and front housing16. This additional support reduces the tendency to create an opening similar to opening18′ of the prior art and it reduces the stress on front bearing72of front housing16.

Referring now toFIGS. 7A and 7B, a mounting system in accordance with another embodiment of the present disclosure is illustrated inFIG. 7B. In the embodiment described above, as shown inFIG. 7A, pilot ring112is a C-shaped pilot which does not interfere with lever94inside center casing30as illustrated by a dashed line inFIG. 7B. As disclosed inFIG. 7B, center casing30can be increased in diameter and a full circle shape pilot ring212can be used in place of pilot ring112. Front housing16will also have to be designed to mate with the increased diameter center casing30.