JPH05325758A - Contact body structure of magnet switch for starter - Google Patents

Abstract

PURPOSE:To improve radiating property of the contact part of a magnet switch for starter and suppress the increase of manufacturing cost. CONSTITUTION:In a magnet switch for starter, protruding parts 27a and recessed parts 27b are formed chequerwise by punching on the contact surface of a fixed contact body 23a connected to a battery 26. On the contact surface 22a of a movable contact body 22, protruding parts 28a and recessed parts 28b are similarly formed by punching in the part making contact with the other fixed contact body 23b connected to a motor 2. Thus, radiating property by the protruding and recessed parts is ensured to prevent a rise of the contact resistance by high temperature. The protruding and recessed parts are provided on the positive electrode side of each contact body where the temperature becomes high at the time of arc generation without applying the irregular working to each contact body, whereby the working cost can be suppressed.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a pair of fixed contact bodies,
The present invention relates to a contact body structure of a starter magnet switch having a plate-shaped movable contact body for selectively short-circuiting both fixed contact bodies.

[0002]

2. Description of the Related Art In a magnet switch for a starter of an automobile, an electric current is selectively applied to an exciting coil to move a movable iron core, and the pinion gear is shifted by the displacement of the movable iron core to mesh with a ring gear. Has been Further, a rod that is displaced according to the displacement of the movable iron core is provided, and the plate-shaped movable contact body integrally attached to the rod is selectively brought into contact with a pair of fixed contact bodies fixedly mounted on the switch cover. By doing so, the two fixed contact bodies are short-circuited to electrically connect the battery and the motor.

In the above magnet switch, a relatively large current flows when the switch is turned on, so that the contact surface of the contact becomes hot and the contact resistance increases, which may deteriorate the efficiency. Japanese Utility Model Application Laid-Open No. 53-155060 discloses a movable contact body in which unevenness is formed on the contact surface to prevent slippage at the time of contact and stabilize the contact state. By forming the unevenness on the contact surface in this manner, the heat radiation area of the contact portion can be increased, and the heat radiation property can be improved. However, forming unevenness on the entire contact surface of the fixed contact body and the movable contact body is
There is an inconvenience that the processing cost increases and the component cost rises.

[0004]

By the way, it is conceivable that the heat generation is caused by an arc generated between the contacts. When an arc occurs, the anode is generally hotter than the cathode. Therefore, it is preferable to enhance the heat dissipation of the anode between the contacts. In view of such problems of the conventional technology, a main object of the present invention is to provide a contact body structure of a magnet switch for a starter capable of improving heat dissipation of a contact contact portion and suppressing an increase in manufacturing cost. It is in.

[0005]

According to the present invention, a starter having a pair of fixed contact bodies and a movable contact body for selectively short-circuiting the two fixed contact bodies is provided. A contact body structure for a magnet switch for use, wherein one of the fixed contact bodies, which is connected to the positive power source side, of the two fixed contact bodies has an uneven contact surface, and the other fixed contact of the movable contact body is formed. The present invention is achieved by providing a contact body structure of a magnet switch for a starter, which is characterized in that a contact surface that comes into contact with the body is formed to be uneven.

[0006]

As described above, by forming the contact surface of the one fixed contact body connected to the positive power source side in a concavo-convex manner, between the one fixed contact body and the movable contact body, Since the contact surface on the anode side is formed in a concavo-convex shape, it is possible to enhance the heat dissipation of the contact surface having a higher temperature when the arc is generated. Between the movable contact body and the other fixed contact body, the contact surface of the movable contact body, which is relatively on the anode side, is formed in a concavo-convex shape, so that the heat dissipation can be similarly enhanced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a side sectional view showing a main part of a starter 1 attached to an engine of an automobile to which the present invention is applied, broken along the axial direction. This starter 1
The pinion gear 3 rotated by the motor 2 is for selectively engaging with a ring gear 4 of an engine (not shown) to drive the pinion gear 3 by turning on / off a magnet switch 5 provided integrally. And the rotation of the motor 2 are performed. As shown in the figure,
A shift fork 7 is interposed between both the movable iron core 6 of the magnet switch 5 and the pinion gear 3, so that the pinion gear 3 is selectively shifted in conjunction with the axial displacement of the movable iron core 6. The movable iron core 6 and the pinion gear 3 are connected via a shift fork 7.

The pinion gear 3 is coaxially fitted on a pinion gear support shaft 8 parallel to the axis of the motor 2.
The pinion gear support shaft 8 is, for example, spline-coupled so that torque can be transmitted in the rotational direction and the shaft can reciprocate in the axial direction. The pinion gear support shaft 8 is hollow, and a shift shaft 9 connected to the pinion gear 3 is coaxially inserted therein. The shift shaft 9 is elastically biased by a return spring 11 in a direction to shift the pinion gear 3 in the retracted direction. Then, one end of the shift fork 7 is in contact with the rear end surface of the shift shaft 9, and the other end of the shift fork 7 is engaged in the groove of the projecting end of the movable iron core 6.

On the outer peripheral surface of the pinion gear support shaft 8, an input gear 12 gear-coupled to the drive shaft of the motor 2 is relatively rotatably provided, and the input gear 1 is also provided.
A one-way clutch 13 for transmitting the torque transmitted to the pinion gear support shaft 8 to the pinion gear support shaft 8 is provided.

In the starter 1 constructed as described above, when the coil described later on the magnet switch 5 is excited, the movable iron core 6 is displaced in the retracted direction which is the direction of arrow A in the figure, and accordingly. As the shift fork 7 swings clockwise in the drawing, the pinion gear support shaft 8 is pushed out in the direction of arrow B in the drawing against the urging force of the return spring 11. At the same time, a current flows through the motor 2 due to the switching operation of the magnet switch 5, and the input gear 12
And the pinion gear support shaft 8 via the one-way clutch 13.
The drive torque of the motor 2 is transmitted to the pinion gear 3 and the pinion gear 3 rotates together with the pinion gear support shaft 8. Therefore, the pinion gear 3 is able to drive the ring gear 4 by the torque transmitted from the motor 2 while rotating and entering the ring gear 4 and engaging with the ring gear 4.

Next, the internal structure of the magnet switch 5 will be described below with reference to a side view of the main part in FIG.
A coil bobbin 15 is provided in a yoke 14 made of a magnetic material that forms a bottomed tubular casing of the magnet switch 5.
An exciting coil wound around the outer peripheral surface of the is coaxially received. The exciting coil includes an attraction coil 16a formed by winding a conductor having a relatively large diameter on the inner peripheral side, and a holding coil 16b formed by winding a conductor having a relatively small diameter on the outer peripheral side.

The movable iron core 6 is reciprocally supported in the axial direction by the axial through hole opening at the center of the bottom of the yoke 4 and the inner peripheral surface of the coil bobbin 15. At the inner peripheral portion of the coil bobbin 15, the boss portion of the fixed iron core 17 is received on the side opposite to the support portion side of the movable iron core 6. A return spring 18 is interposed between the fixed iron core 17 and the movable iron core 6 to return the movable iron core 6 to the original position when the exciting coil 15 is demagnetized.

The plunger 19 is reciprocally supported in the axial direction by an axial penetrating hole formed in the axial center portion of the fixed iron core 17. One end of the plunger 19 faces the movable iron core 6, and the other end is received in the switch chamber 20 defined between the outward flange portion of the fixed iron core 17 and the bottomed tubular switch cover 21. The plunger 1
A movable contact body 22 is attached to the other end of the movable contact body 22 that is prevented from coming off by a collar portion 19a formed at the other end. The switch cover 21 has a pair of fixed contact bodies 23a and 23b at a portion of the inner surface thereof facing the movable contact body 22.
Are arranged. One fixed contact body 23a forms a positive contact that is connected to the positive terminal of a battery (not shown) on the positive power supply side, and the other fixed contact body 23b is a negative contact connected to the power input terminal of the motor 2. It forms a side contact.

The movable contact body 22 is attached to the plunger 19 via an insulating insulator 24. The contact spring is a conical compression coil spring interposed between the fixed iron core 17 and the insulator 24. Is elastically urged toward the fixed contact bodies 23a and 23b. Therefore, the plunger 19 is fixed to the fixed contact body 2
When the movable contact body 22 and the fixed contact bodies 23a and 23b are brought into contact with each other by being displaced to the 3a / 23b side, the contact state is secured with a predetermined urging force. A return compression coil spring is interposed between the flange portion 19a of the plunger 19 and the facing inner surface of the switch cover 21,
As a result, in the initial state, the plunger 19 is biased toward the fixed iron core 17 side as shown in FIG.

One ends of the above-mentioned coils 16a and 16b are connected to each other and connected to a switch terminal 25 projecting outward from the switch cover 21 through the outward flange of the coil bobbin 15. An ignition switch (not shown) is electrically connected to the switch terminal 25, the other end of the holding coil 16b is grounded through the fixed iron core 17, and the other end of the suction coil 16a is connected to the motor connection terminal described above. Is connected to the fixed contact body 23b.

According to the magnet switch 5, the movable iron core 6 is attracted to the fixed iron core 17 by energizing both the coils 16a and 16b as the exciting coils. The plunger 19 is displaced along with the suction operation of the movable iron core 6, and accordingly, the movable contact body 22 is moved to both the fixed contact bodies 23.
The fixed contacts 23a and 23b are electrically short-circuited by abutting on the a and 23b, and the current from the battery flows to the motor 2.

By the way, in the present magnet switch 5, as shown in FIG. 3, the contact surface of one fixed contact 23a connected to the positive terminal of the battery 26 is in contact with the movable contact 22. Is provided with a plurality of convex portions 27a and concave portions 27b. Further, on the contact surface 22a of the movable contact body 22, a plurality of convex portions 28a and concave portions 28b are provided in a portion in contact with the other fixed contact body 23b connected to the motor 2. Therefore, the movable contact body 22 and the two fixed contact bodies 23a and 23b are provided with the respective convex portions 27a and 28b.
It comes into contact via a.

In order to form the above-mentioned concave and convex portions, for example, a punch having a plurality of protrusions formed with the same square end face shape and arranged at a predetermined pitch in mutually orthogonal directions is used. It can be processed.
That is, once punching is performed, a plurality of checkerboard-like punch holes are formed in the vertical and horizontal directions, and then the punching is performed by shifting the punches in the vertical and horizontal directions by half the pitch of the protrusions. The holes are formed in a staggered manner, and the part that has not been punched is projected relative to both punch holes, forming a plurality of convex parts and a plurality of concave parts. It becomes a checkered pattern.

In this way, one fixed contact body 23a
An uneven checkered pattern composed of a plurality of convex portions 27a and concave portions 27b is formed on the contact surface of the movable contact body 22.
A plurality of convex portions 28a and concave portions 2 on a part of the contact surface 22a of the
An uneven checkerboard pattern composed of 8b is formed. Therefore, the respective convex portions 27a are provided independently of each other, so that the convex portion 27a has a good heat dissipation effect against the heat generated by the current flowing at the time of contact with the contact point, which causes an increase in contact resistance due to heat accumulation. It can be prevented as much as possible. This is the convex portion 28
The same applies to a. In addition, since the unevenness is formed on the contact surface of each of the contacts, which is on the side of the anode, which is relatively on the side of the anode, the heat dissipation of the higher temperature is generally secured at the time of arcing. It is possible to obtain a heat dissipation effect without forming unevenness on all of the above.

In this embodiment, one fixed contact body 23a is connected to the positive terminal of the battery, which is the positive power source side, but the other fixed contact body 23b is the positive power source side. You can also do it.

[0022]

As described above, according to the present invention, it is possible to secure a good heat dissipation property due to the uneven shape of the contact surface of the contact, and to form a pair of fixed contacts without performing the uneven processing on the entire contact surface. Between the contact surface of the body and the movable contact body, the contact surface of the one on the side of the positive power source, which is relatively positive, is formed to be uneven, and the heat dissipation at the higher temperature when an arc occurs is preferably secured. By doing so, it is possible to suppress a rise in manufacturing cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional side view of a main part of an automobile starter to which the present invention is applied.

FIG. 2 is an enlarged side sectional view showing a main part of the magnet switch according to the present invention in a cutaway manner.

FIG. 3 is a perspective view showing a pair of a fixed contact body and a movable contact body according to the present invention.

[Explanation of symbols]

 1 starter 2 motor 3 pinion gear 4 ring gear 5 magnet switch 6 movable iron core 7 shift fork 8 pinion gear support shaft 9 shift shaft 11 return spring 12 input gear 13 one-way clutch 14 yoke 15 coil bobbin 16a suction coil 16b holding coil 17 fixed iron core 17a Outward flange portion 18 Return spring 19 Plunger 19a Collar portion 20 Switch chamber 21 Switch cover 22 Moving contact body 22a Contact surface 23a / 23b Fixed contact body 24 Insulator 25 Switch terminal 26 Battery 27a / 28a Convex portion 27b / 28b Recessed portion

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Nagashima 1-2681 Hirosawa-cho Kiryu-shi Gunma Mitsuba Electric Manufacturing Co., Ltd. (72) Inventor Minoru Kimura 1261 Hirosawa-machi Kiryu-shi Gunma Mitsuba Electric Mfg. Co., Ltd. (72) Inventor Mitsuhiro Kogure 1268-1, Hirosawa-cho, Kiryu-shi, Gunma Mitsuba Electric Mfg. Co., Ltd.

Claims (1)

[Claims] 1. A contact body structure for a starter magnet switch, comprising: a pair of fixed contact bodies; and a movable contact body for selectively short-circuiting the fixed contact bodies. One of the fixed contact bodies connected to the positive power source side of the movable contact body is formed in an uneven shape, and the contact surface of the movable contact body that contacts the other fixed contact body is formed in an uneven shape. Contact body structure of magnet switch for starter.