JPH1130169A - Magnetic switch for starter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of chattering and welding between contacts by providing a stopper movable in the moving direction of a movable contact, in a position opposed to the movable contact so as to make the movable contact collide with the stopper before the movable contact collides with a fixed contact at the time of a magnetic switch being operated. SOLUTION: When a current flows to an exciting coil 3 to attract a plunger 4 at the time of a magnetic switch 2 being put in action, a movable shaft 6 moves, and a movable contact 5 collides with a stopper 8. Since the mass of this stopper 8 is equivalent to the total mass of the movable contact 5 and a movable contact pressing member 12, the axial moving speed of the movable contact 5 and movable contact pressing member 12 is instantaneously reduced to zero. When the movable shaft 6 further moves while bending a contact pressing spring 11, the movable contact 5 is jointed to a fixed contact 7, but since the movable contact 5 is further pressed by spring force from the state of colliding with the stopper 8, the speed of the movable contact 5 at the time of colliding with the fixed contact 7 is low.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starter for starting an internal combustion engine, and more particularly to an improvement in reliability and durability of a magnetic switch suitable for a starter for starting an internal combustion engine.

[0002]

2. Description of the Related Art A conventional magnetic switch is known, for example, from JP-A-6-280719. In the magnetic switch described in the publication, when a current is supplied to the exciting coil, the plunger is attracted, and at the same time, the shaft with the movable contact is pushed out, and the movable contact and the fixed contact are joined to supply electricity to the motor.

When the power supply to the exciting coil is cut off, the plunger returns to its original position due to a spring reaction force. Also, the shaft with the movable contact returns to the original position due to the spring reaction force, the contact is opened, the power supply to the electric motor is released, and the rotation stops.

[0004]

In the above-mentioned prior art, when the movable contact collides with the fixed contact at a certain speed, the movable contact reacts to generate chattering, and the contact heat is melted by the arc heat to cause welding between the contacts. The contact may not be easily opened by the spring reaction force that returns the shaft even when the power supply to the exciting coil is cut off. If the contacts do not open, the motor will be damaged by continuous energization.

The present invention has been made in view of these points. An object of the present invention is to prevent chattering and welding between contacts by avoiding violent collision between a movable contact and a fixed contact of a magnetic switch. It is an object of the present invention to provide a starter magnetic switch having high reliability and excellent durability by preventing the occurrence of the magnetic switch.

[0006]

The object of the present invention is to provide a stopper which is movable in the moving direction of the movable contact at a position opposed to the movable contact so that when the magnetic switch is actuated, the movable contact comes into contact with the fixed contact. , As a structure in which the movable contact and the stopper collide, the mass of the stopper is equivalent to or less than the total mass of the movable contact and the movable contact pressing member that moves integrally with the movable contact. It is achieved by doing.

According to this structure, chattering and welding between the contacts are prevented by preventing the movable contact and the fixed contact of the magnetic switch from violently colliding with each other, thereby improving reliability and durability. It can be greatly improved.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a magnetic switch 2 for a starter using the present invention.

When the start switch is turned on, a current flows from the battery (not shown) to the exciting coil 3, the plunger 4 is attracted, and the rear end 6a of the movable shaft 6 having the plunger inner bottom 4a and the movable contact 5 hits. The suction is further performed while pressing the movable shaft 6.

There is a fixed contact 7 at the moving destination of the movable contact 5, and each of the fixed contacts 7 is connected to a battery B.
It is configured integrally with a terminal 7a and an M terminal 7b connected to the electric motor 1 of the starter. When the movable shaft 6 is further sucked and the movable contact 5 is joined to the fixed contact 7, electricity is supplied from the battery to the motor 1 through the B terminal 7a, the movable contact 5 and the M terminal 7b,
The electric motor 1 starts rotating.

FIG. 2 shows a sectional view of a magnetic switch according to the present invention. The stopper 8 is held by a plate 9 and a stopper return spring 10 in a normal state, and when a load is applied from the direction of the movable contact 5, the stopper 8 deflects the stopper return spring 10 to move the movable contact 5.
It can be moved in the direction of movement.

Here, the movable contact 5 and the fixed contact 7 in the normal state
The gap in the axial direction is L1, the movable contact 5 and the stopper 8
The gap in the axial direction is L2, and L2 is configured to be slightly smaller than L1.

Next, the operation of the apparatus configured as described above will be described. 3 to 5 are cross-sectional views of the magnetic switch during operation.

FIG. 3 shows that a current flows from the battery (not shown) to the exciting coil 3, the plunger 4 is sucked, and further sucked while pushing the movable shaft 6, the movable shaft 6 moves, and the movable contact 5 is moved to the stopper 8. FIG.

At this time, the stopper 8 is movable in the moving direction of the movable contact 5 with a mass equivalent to the total mass of the movable contact 5 and the movable contact pressing member 12 moving integrally with the movable contact 5. Therefore, the moving speed in the axial direction of the movable contact 5 and the movable contact pressing member 12 instantaneously becomes zero. On the other hand, the stopper 8 moves in the moving direction of the movable contact 5 at the same speed as the speed of the movable contact 5 at the time of collision. Therefore, the fact that the movable contact 5 attempts to join the fixed contact 7
The stopper 8 does not interfere.

Next, as shown in FIG. 4, the plunger 4 is further sucked, and the movable shaft 6 further moves while bending the contact pressing spring 11. The stopper 8 moves in the moving direction of the movable contact 5 by the energy of the collision. Movable contact 5
Moves to the fixed contact 7 side again by the spring force of the contact pressing spring 11.

When the movable contact 5 is joined to the fixed contact 7,
The moving speed of the movable contact 5 at the time of the collision is reduced by the collision with the stopper 8 to 0, and is further pushed by the spring force. The speed of the contact 5 is reduced. As a result, it is possible to prevent chattering in which the movable contact 5 flutters away from the fixed contact 7 due to the recoil of the collision, and to prevent welding from occurring between the contacts.

FIG. 5 is a cross-sectional view of the plunger at the maximum suction time. The stopper 8 is held by the movable contact holding member 13 at a position moved in a moving direction of the movable contact 5 from a predetermined position. Therefore, the stopper 8 is returned to the original position by the spring force of the stopper return spring 10 and does not collide with the movable contact 5 and the movable contact 5 does not separate from the fixed contact 7.

In this state, the motor 1 from the battery passes through the B terminal 7a, the movable contact 5 and the M terminal 7b.
, The electric motor 1 starts rotating, and its rotational force is transmitted to the internal combustion engine to start the internal combustion engine.

With such a structure, it is possible to prevent the movable contact and the fixed contact from violently colliding.

[0021]

According to the present invention, the occurrence of chattering and the occurrence of welding between the contacts can be prevented by avoiding a violent collision between the movable contact and the fixed contact of the magnetic switch, thereby improving the reliability. A magnetic switch for a starter having excellent durability can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a starter using a magnetic switch according to the present invention.

FIG. 2 is a sectional view of a magnetic switch showing an embodiment of the present invention.

FIG. 3 is a cross-sectional view of the magnetic switch of the present invention at the time of operation.

FIG. 4 is a cross-sectional view of the magnetic switch of the present invention at the time of operation.

FIG. 5 is a cross-sectional view of the magnetic switch of the present invention at the time of operation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electric motor, 2 ... Magnetic switch, 3 ... Exciting coil, 4 ... Plunger, 4a ... Plunger inner bottom part, 5
.. Movable contact, 6 movable shaft, 6a rear end of movable shaft, 7 fixed contact, 7a B terminal, 7b M
Terminal, 8: stopper, 9: plate, 10: stopper return spring, 11: contact pressing spring, 12: movable contact pressing member, 13: movable contact holding member, L1: axial gap between movable contact and fixed contact, L2 ... A gap in the axial direction between the movable contact and the stopper.

Claims (5)

[Claims] An exciting coil responsive to opening and closing of a start switch, a plunger movable by being urged by the exciting coil, a shaft with a movable contact, and a fixed contact forming a drive circuit of a starter motor by joining the movable contact. A magnetic switch for a starter, comprising: a magnetic switch for a starter, comprising: a stopper movable in a moving direction of the movable contact at a position facing the movable contact. 2. The magnetic switch for a starter according to claim 1, wherein when the magnetic switch is operated, the movable contact collides with the stopper before the movable contact collides with the fixed contact. . 3. The mass of the stopper is equivalent to or less than the total mass of the movable contact and the movable contact pressing member that moves integrally with the movable contact. Item 2. A magnetic switch for a starter according to Item 1. 4. The starter according to claim 1, wherein when the magnetic switch is operated, the stopper is held at a position moved from a predetermined position in a moving direction of the movable contact. Magnetic switch. 5. The magnetic switch according to claim 1, wherein the stopper is made of an insulating material.