Motor terminal portion structure

A motor terminal portion structure is provided which can satisfactorily drain the water in an insulating member surrounding the outer circumference of a terminal and prevent water from entering the insulating member, in addition to allowing the insulating member to be commoditized without being influenced by motor layout. A motor terminal portion structure includes an insulator that is formed in a cylindrical shape surrounding the outer circumference of a terminal and is secured to a bracket. A drain hole is provided to establish communication between the inside and outside of the insulator. A flange portion shields an opening of the drain hole on the outside of the insulator. A plurality of the drain holes are disposed around the terminal. The outer side surface of the insulator and the inside surface of the flange portion are each formed in regular polygon so as to conform to each other. A portion of the flange portion facing vertically downward in an on-board state is formed as a notch.

CROSS-REFERENCE TO RELATED APPLICATIONS

This nonprovisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No. 2005-138372, filed in Japan on May 11, 2005, the entirety of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a terminal portion structure of a motor mounted on a vehicle.

2. Description of Background Art

In Japanese Patent Laid-Open No. 3027900, a conventional terminal structure is configured such that a dish-like insulator (insulating member) is attached to a terminal of an alternator (motor) and is formed with drainage slits (drain holes) at four outer circumferential positions thereof.

Draining the water in the insulating member through the drain holes needs to expose at least part of the drain holes through an insulating cap attached to the insulating member. If the exposed part of the drain holes faces upward in terms of the motor layout; however, water may enter the insulating member through the drain hole.

In this case, it is conceivable to change the positions of the drain holes of the insulating member in accordance with the motor layout. However, this makes it inevitable to provide a plurality of different types of insulating members, which is unpreferable in terms of commoditizing parts.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a motor terminal portion structure that is capable of satisfactorily draining the water in an insulating member surrounding the outer circumference of a terminal and is capable of preventing water from entering the insulating member, in addition to allowing the insulating member to be commoditized without being influenced by motor layout.

As means for solving the problem, a first aspect of the present invention is directed to a motor terminal portion structure in which a terminal (e.g., the terminal11of the embodiment) is projectingly provided on a bracket (e.g., the bracket6of the embodiment) constituting one side of a motor (e.g., the motor1of the embodiment). An insulating member (e.g., the insulator20,40of the embodiment) is formed in a cylindrical shape surrounding the outer circumference of the terminal and is secured to the bracket. A drain hole (e.g., the drain hole28of the embodiment) is provided to establish communication between the inside and outside of the insulating member. A flange portion (e.g., the flange portion30of the embodiment) shields an opening (e.g., the opening29of the embodiment) of the drain hole on the outside of the insulating member.

With this configuration, the opening of the drain hole on the outside of the insulating member is shielded by the flange portion. Therefore, the insulating member is prevented from being exposed. Thus, even if the periphery of the insulating member is splashed with water, the water can be prevented from entering the inside of the insulating member. It should be noted that the motor described above can be a generator as well as an electric motor.

According to a second aspect of the present invention, the insulating member has an outside flat portion (e.g., the outside flat portion21bof the embodiment) on an outside surface (e.g., the outer circumferential surface21a) thereof. The flange portion is formed integral with the bracket and has an inside flat portion (e.g., the inside flat portion30bof the embodiment) on an inside surface (e.g., the inside surface30aof the embodiment) thereof. The inside flat portion conforms to the outside flat portion.

With this configuration, when the outside flat portion of the insulating member and the inside flat portion of the flange portion are conformably fitted to each other, they function as a lock when the insulating member is secured to the bracket. Thus, assembling of the insulating member can be enhanced. In addition, the flange portion is formed integral with the bracket. Therefore, the number of components can be reduced as compared with when the flange portion is formed as a single piece.

According to a third aspect of the present invention, the insulating member is formed on one side thereof with a slit (e.g., the slit24of the embodiment) for connection with an external terminal (e.g., the external terminal14) to be connected to the terminal and a plurality of the drain holes are arranged radially around the terminal.

With this configuration, the plurality of drain holes are radially arranged in the insulator. Therefore, even if the insulator is shared by motors that are different from each other in the terminal connection direction, drainage can be ensured. In other words, in addition to the fact that the insulator can be shared by a plurality of motors, the drainage of the insulator can be ensured.

According to a fourth aspect of the present invention, the outside surface of the insulating member is formed in a polygonal shape comprising a plurality of outside flat portions. The flange portion is disposed around the polygonal shape to conform thereto and the flange portion has a notch (e.g., the notch31of the embodiment) at a portion facing vertically downward in an on-board state.

With this configuration, locking can be ensured when the insulator is secured to the bracket. Furthermore, in addition to that fact that the vertical-downward drainage in the on-board state can be ensured, water can be prevented from entering the inside of the insulator when the periphery of the insulator is splashed with the water.

According to a fifth aspect of the present invention, an attachment portion (e.g., the attachment portion7of the embodiment) is provided to attach the motor to a vehicle at a position under the notch of the flange portion and is formed with an eave.

With this configuration, even if the motor is removed from the vehicle, it is possible to prevent water or dust from entering the inside of the insulator from the drain hole exposed from the inside of the notch since the eaved attachment portion is provided on the side (the lower side in the on-board state) where the notch of the flange portion is provided.

According to the first aspect of the present invention, even if the periphery of the insulating member is splashed with water, the water can be prevented from entering the inside of the insulating member.

According to the second aspect of the present invention, assembling of the insulating member can be enhanced, and the number of components can be reduced as compared with when the flange portion is formed as a single piece.

According to the third aspect of the present invention, in addition to the fact that the insulator can be shared by a plurality of motors, the drainage of the insulator can be ensured.

According to the fourth aspect of the present invention, locking of the insulator can be ensured. Furthermore, in addition to that fact that the drainage of the insulating member can be ensured, water can be prevented from entering the inside of the insulator.

According to the fifth aspect of the present invention, even if the motor is removed from the vehicle, it is possible to prevent water or dust from entering the inside of the insulator from the drain hole.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings, wherein the same or similar elements will be identified with the same reference numerals.

A motor1shown inFIGS. 1 and 2is a starter motor for a motorcycle, for instance. The motor1includes an almost-cylindrical casing2. A stator3is secured in the inside of and on the outer circumferential side of the casing2. A rotor4is disposed for rotation on the inner circumferential side of the casing2. The rotor4is integrally connected to a rotary shaft5that passes therethrough. The rotary shaft5is carried for rotation by the casing2.

When electric power from an on-board battery is fed to the motor1, the rotor4and rotary shaft5are drivingly rotated integrally. Such a motor1is mounted to the vehicle with its rotary axis C being parallel thereto. It should be noted that the following description is made on the assumption that arrow RR in the figures denotes the rearward direction (axial direction) along the rotary shaft C when the motor1is mounted on the vehicle; arrow UP denotes an up-and-down direction when the motor1is mounted on the vehicle; and arrow LH denotes the left direction as viewed forward (as viewed inFIG. 2) taken along the axial direction when the motor1is mounted on the vehicle.

An attachment portion7is provided at the rear end of the casing2to attach the rear portion of the motor1to the vehicle. The rear end of the casing2is configured as a bracket6formed integral with the attachment portion7. A terminal11for connection with the positive electrode of the on-board battery is provided above the bracket6so as to project rearward along the motor rotary axis C. The bracket6is made of metal and the attachment portion7is joined to the vehicle body to ground the motor1.

The terminal11is such that the neck-under-portion of the terminal bolt12that passes through the rear wall of the bracket6from the inside of the casing2projects rearward. The terminal bolt12and a nut13threaded thereto are fastened with the rear wall of the bracket6. An insulating member such as an insulator20or the like is located therebetween. Thus, the bracket6and the terminal bolt12and the nut13are joined together while the insulation therebetween is maintained. It should be noted that the symbol T in the figure denotes the axis of the terminal11.

The insulator20is made of an insulating resin. In addition, the insulator20is cylindrical and is disposed to surround the outer circumference of the terminal11. The insulator20has a front end21formed with a shelf portion22projecting to the inner circumferential side. A collar23is fittingly attached, from the rear, to the opening of the shelf portion22on the inner circumferential side. The collar23is made similarly of an insulating resin and has a flange in contact, from the rear, with the shelf portion22. The terminal bolt12and the nut13are fastened while the respective front ends of the collar23and insulator20are in contact with the rear surface of the bracket6. Thus, the collar23and insulator20are secured to the bracket6together with the terminal bolt12and nut13.

FIGS. 1 to 4illustrate an example in which an external terminal14secured to the terminal11with a nut17and a harness15connected to the external terminal14extend above the terminal11. With such a motor layout, the insulator20is provided at an upper part with a slit24that is adapted to extend the external terminal14and the harness15from the terminal11inside the insulator20.

An insulating cap16that is adapted to shield the periphery of the external terminal14is attached to a tip of the harness15. The insulating cap16is mounted to the rear end of the insulator20. Thus, the opening of the rear end and the slit24are closed, and the peripheries of the terminal11and the external terminal14are covered with the insulator20and the collar23, and the insulating cap16so as to be insulated from the outside.

With additional reference toFIGS. 3 to 6, the shelf portion22at the front end21of the insulator20has an inside surface (inner circumferential surface) which is in a circular shape concentric with the terminal axis T as viewed axially. In addition, the shelf portion22has an outside surface (outer circumferential surface)21awhich is in an octagonal shape concentric with the inside surface as viewed axially.

The insulator20has a portion (hereinafter referred to as an outer wall25) excluding the front end21. The lower half of the outer wall25is formed with an outside surface shaped in a polygon, as viewed axially, conforming to the external profile of the front end21. An inside surface of the outer wall25is shaped in a semicircle as viewed axially.

The upper half of the external wall25is formed to have a circular arc-shaped outside surface at a portion protruding upward from the outer profile of the front end21as viewed axially. A widthwise center region of an upper wall forming the circular arc-shaped outside surface, which region is rearward of the axial substantial center of the insulator20, is cut away to form the slit24.

Drains26that are used to drain water that has entered the insulator20to the outside are formed at both or left and right side portions, a lower portion, and a portion between each of the left and right side portions and the lower portion, in the inside surface of the external wall25. More specifically, the drains26are disposed around the terminal axis T in the lower half of the insulator20, and are each formed semicircular in section and extend axially.

The drains26are each formed to entirely extend from the rear end to the front end21of the insulator20. With such a configuration, the respective portions, of the shelf portion22, corresponding to the drains26are each cut away at a width equal to that of the drain26to be open toward the inner circumferential side.

A front end drain27extending from the inside surface to the outside surface21aof the front end21is formed at a portion corresponding to each of the drains26at the front end of the insulator20. Consequently, even when the insulator20is fixed, the inside and outside of the insulator20communicate with each other through the drains26and the front end drains27, thereby draining the water in the insulator20to the outside. In other words, the drains26are each paired with a corresponding one of the front end drains27to form a drain hole28of the insulator20.

The bracket6is provided at a rear surface with a projecting flange portion30extending along the outside surface21aof the front end21included in the insulator20so as to surround it. The flange portion30is provided so that an inside surface (inner circumferential surface)30amay be conformably fitted to the outside surface21aof the front end21. More specifically, the outside surface21aof the front end21is formed in an octagon, as viewed axially, composed of eight outside flat portions21b. On the other hand, the inside surface30aof the flange portion30is formed in an octagon, as viewed axially, composed of eight inside flat portions30bcorresponding to the respective outside flat portions21b. Since the front end21is fitted in the flange portion30thus formed, the insulator20is locked when the nut13is fastened to secure the insulator20to the bracket6.

Additionally, with the insulator20secured to the bracket6, the flange portion30is provided to shield the opening29of each drain hole28on the outside surface21aof the front end21. However, a notch31is formed at a portion, of the flange portion30, facing vertically downward with the motor1mounted on the vehicle so as to expose to the outside only an opening29that faces vertically downward when the motor1is mounted on the vehicle.

As shown inFIGS. 2 and 7, the attachment portion7provided on the rear surface of the bracket6includes a pair of bosses8which is disposed on both respective sides of a portion under the terminal11. An eaved portion9extends from the rear surface of the bracket6so as to span between the bosses8. The bosses8are each formed to allow a bolt to pass therethrough in the up-and-down direction. In addition, the plate-like eaved portion9spans between both the bosses8so as to be substantially perpendicular to both bosses8. The attachment portion7described above shields, as viewed from below, the notch31of the flange portion30and the opening29of the drain hole28that is exposed from the inside of the notch31.

FIG. 8illustrates a motor layout in which the external terminal14and the harness15extend leftward of the terminal11. With such a motor layout, the insulator20is secured to the bracket6to turn at an angle of 90° counterclockwise around the terminal axis T from the state as shown inFIG. 2(the state where the slit24faces the upside). Since the front end21and the flange portion30fitted to each other are formed to be octagonal as viewed axially, they are fitted to each other even when the insulator20is turned as mentioned above. That is to say, the front end21and the flange portion30function as a lock for the insulator20at the time of fastening the nut13.

If the front end21and the flange portion30are formed to be octagonal as viewed axially, the rotary angle of the insulator20is a unit of 45 degrees. However, the rotary angle is arbitrarily changeable by the shape of the front end21and flange portion30.

In addition, if the insulator20is turned as mentioned above as well, the drain hole28that was located at the left-hand end inFIG. 2is located at the lower end so as to be exposed vertically downward from the notch31of the flange portion30. Consequently, the same drainage performance as that of the motor layout shown inFIG. 2can be ensured.

As described above, the motor terminal portion structure according to the embodiment is such that the terminal11is projectingly provided on the bracket6constituting one side of the motor1. In addition, the motor terminal portion structure includes the insulator20secured to the bracket6so as to be in a cylindrical shape surrounding the outer circumference of the terminal11. The drain holes28are provided in the insulator20so as to establish communication between the inside and outside thereof. The flange portion30shields the openings29of the drain holes28on the outside of the insulator20.

With this configuration, the openings29of the drain holes28on the outside of the insulator20are shielded by the flange portion30. Therefore, the exposure of the openings29can be prevented. Even when the periphery of the insulator20is splashed with water, the water can be prevented from entering the inside of the insulator20. Thus, the terminal11and the nut13can be prevented from rusting and electrically corroding.

In the motor terminal portion structure, while the insulator20has outside flat portions21bon the outside surface21aof the front end21thereof, the bracket6is formed integrally with the flange portion30and the flange portion30is provided on its inside surface30awith an inside flat portion30bconforming to the outside flat portion21b. Therefore, when the outside flat portion21bof the insulator20and the inside flat portion30bof the flange portion30are conformably fitted to each other, they function as a lock when the insulator20is secured to the bracket6. This improves the assembly of the insulator20. In addition, since the flange portion30is formed integral with the bracket6, the number of components can be reduced as compared with when the flange portion30is formed as a separate part.

Furthermore, in the motor terminal portion structure, while the insulator20is formed on its one side with the slit24used for connection with the external terminal14to be connected to the terminal11, a plurality of the drain holes28are radially disposed around the terminal11. Therefore, even if the insulator20is shared by different motors in the external terminal connection direction, drainage can be ensured since the plurality of drain holes28are radially arranged. In other words, in addition to the fact that the insulator20can be shared by a plurality of motors, the drainage of the insulator20can be ensured.

In the motor terminal portion structure, while the outside surface21aof the insulator20is formed in a regular polygon formed of a plurality of the outside flat portions21b, the flange portion30is disposed around the polygon so as to conform thereto. That is, the inner circumferential surface of the flange portion30is formed in a regular polygon formed of a plurality of the inside flat portions30bconforming to the outside flat portions21b. In addition, a portion of the flange portion30facing vertically downward in an on-board state is formed as the notch31. Therefore, locking can be ensured when the insulator20is secured to the bracket6. In addition to that fact that the vertical-downward drainage performance in the on-board state can be ensured, water can be prevented from entering the inside of the insulator20when the periphery of the insulator20is splashed with the water. Since the insulator20can be turned for each specified angle, design freedom with regard to the connection direction to the external terminal can be increased.

Additionally, with the motor terminal portion structure described above, the attachment portion7used to attach the motor1to the vehicle is provided under the notch31of the flange portion30and is formed to be eaved. Therefore, even if the motor1is removed from the vehicle, it is possible to prevent water or dust from entering the inside of the insulator20through the drain hole28exposed from the inside of the notch31since the eaved attachment portion7is provided on the side (the lower side in the on-board state) where the notch31of the flange portion30is provided.

The present invention is not limited to the embodiment described above. For example, as an insulator40shown inFIG. 9, a front end41(not shown in the figure) may be set to a size smaller than the external shape of an outer wall42(not shown in the figure). In this case, the flange portion30of a bracket6is also reduced in size to suit with the front end41, so that applicability to the small-sized motor can be enhanced. It should be noted again that portions corresponding to those in the embodiment described above are denoted with the same reference numerals and its explanation is omitted.

In addition, the insulator20and the terminal11may be configured to be separately secured to the bracket6. Furthermore, the flange portion30may be formed integral with or separate from the insulator20.

The configuration of the embodiment described above is one example of the invention, is applicable to a motor (electric motor) as well as a generator (electric dynamo), and needless to say, can be variously modified without departing from the gist of the invention.