Magnet switch for starter

• US 20030193382A1
• Filed: 03/31/2003
• Published: 10/16/2003
• Est. Priority Date: 04/12/2002
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Niimi, Masami, Shiga, Tsutomu
• Granted Patent: US 6,710,690 B2
• Time in Patent Office: Days
• US Class Current: 335/126
• CPC Class Codes: F02N 11/087 Details of the switching means in starting circuits, e.g. relays or electronic switches
• CPC Class Codes: H01H 50/543 Auxiliary switch inserting resistor during closure of contactor
• CPC Class Codes: H01H 51/065 Relays having a pair of normally open contacts rigidly fixed to a magnetic core movable along the axis of a solenoid, e.g. relays for starting automobiles details H01H50/20

Abstract

A magnet switch has a coil of a reduced size and a sufficiently large contact and does not have a rod running through the plunger or the fixed iron core. A flange and a joint are fixed at one end of the plunger. The arm of the flange is connected to a holder via an elastic body. Movable contacts are pushed into the holder to be fixed at one end thereof. When the plunger moves, the flange, the holder, and the movable contacts move somewhat simultaneously to work as a switch.

Claims

1. A magnet switch for a starter, for providing an electric current to a starter motor, the magnet switch comprising:

an attraction coil (51) of a substantially cylindrical shape;

a case (55), wherein the case covers an outer face and a side face of the attraction coil (51),

a fixed iron core (54), wherein one end of the case'"'"'s inner structure is closed with the fixed iron core (54), and wherein the attraction coil (51), the case (55), and the fixed iron core (54) are of a substantially cylindrical shape having a closed bottom;

a

a plunger (52) and the fixed iron core (54) define an air gap (56), wherein

the plunger (52) is disposed within an inner circumference of the attraction coil (51), and

the case (55), the fixed iron core (54), the plunger (52), and the air gap (56) form a magnetic circuit, and

the plunger (52) can move to an opposite side of the fixed iron core (54), pulled by the attraction coil (51) to shorten the air gap (56);

a holder (58) and a joint (53a), wherein

the plunger (52) is directly or indirectly connected to the holder (58); and

the joint (53a) is disposed on the side opposite to the air gap (56);

a movable contact fixed in the holder (58); and

a pinion (25), wherein the joint (53a) is indirectly connected to a connection rod (90) and moves the pinion (25) in accordance with a movement of the plunger (52) during a switching operation.

2. The magnet switch for a starter according to claim 1, wherein the movable contact (82) and the joint (53a) are disposed oppositely, to each other, across the side wall (55b) of the case (55), and wherein the magnet switch further comprises:

a flange (53), fixed to the plunger (52), substantially covers the outer periphery of the case (55), wherein the flange (53), the movable contact (82), the joint (53a), and the plunger (52) are connected to each other.

3. The magnet switch for a starter according to claim 1, wherein

the plunger (52) has the flange (53) and the joint (53a) at its end on the side opposite to the air gap (56),

the flange (53) has an arm (53b) which substantially covers the case (55), and is connected to the holder (62) via the arm (53b),

the movable contact (82) on the side opposite to the flange (53) across the case (55) is fixed by the holder (58) substantially from the outside, and

a fixed contact (81) is disposed in a position facing the movable contact (82).

4. The magnet switch for a starter according to claim 1, wherein the case (55) is fastened to the starter with a band or the like and the outer face of the magnet switch is covered with a cover (98).

5. The magnet switch for a starter according to claim 1, further comprising:

a gear reduction mechanism (30);

an output shaft (20) for driving the gear reduction mechanism (30);

an armature shaft (11), wherein the gear reduction mechanism (30) is installed between the armature shaft (11) and the output shaft (20) and wherein the gear reduction mechanism (30) transmits a reduced number of rotations of the armature shaft (11) to the output shaft (20);

a connection part (90) for reducing rotation of the pinion (25), wherein the movable contact (82) contacts the fixed contact (81) to activate the starter motor, and wherein the magnet switch is disposed at a first end of the starter motor and the pinion (25) is disposed at a second end, and wherein the connection part (90) moves in accordance with the plunger (52) that is moved by the attraction coil (51).

6. A magnet switch for starter, for providing an electric current to a starter motor, having an attraction coil (51) of a substantially cylindrical shape;

wherein an inner face and a side face of the attraction coil (51) are covered with a fixed iron core (54) and both sidewalls, while an outer face thereof includes a cylindrical part, a plunger (52), and an air gap (56);

wherein the fixed iron core (54), the sidewalls, the cylindrical part (55a), the plunger (52), and the air gap (56) form a magnetic circuit;

wherein the plunger (52) can move to an opposite side of the cylindrical part, pulled by the attraction coil (51) to shorten the air gap (56), the plunger (52) being directly or indirectly connected to a holder (58) and a joint (53a) on the side opposite to the air gap (56);

wherein a movable contact (82) is fixed in the holder (58); and

wherein the joint (53a) is connected to a pinion (25) indirectly via a connection rod (90) or the like, and moves the pinion (25) in accordance with the movement of the plunger (52) during a switching operation.

7. The magnet switch for a starter according to claim 6, wherein:

the movable contact (82) and the joint (53a) are disposed on opposite sides to each other across the side wall of the attraction coil (51);

a flange (53) fixed to the plunger (52) covers most of the outer periphery of the cylindrical part; and

the flange (53), the movable contact (82), the joint (53a), and the plunger (52) are connected to each other.

8. The magnet switch for a starter according to claim 6, wherein:

the plunger (52) has the flange (53) and the joint (53a);

the holder (58) covers most of the cylindrical part and its one end is connected to the flange (53);

the joint (53a) is fastened to one end of the plunger (52);

the movable contact (82) is disposed across the attraction coil (51) on the side opposite the joint (53a);

the movable contact (82) is fixed by the holder (58); and

a fixed. contact (81) is disposed in a position facing the movable contact (82).

9. The magnet switch for a starter according to claim 6, wherein an immovable part of the magnet switch is fastened to the starter with a band (95) or the like and the outer face of the magnet switch is covered with a cover (98).

10. The magnet switch for starter according to claim 6, comprising an output shaft (20) and a gear reduction mechanism (30) that is installed between an armature shaft (11) of the starter motor and the output shaft (20) and transmits rotation of the armature shaft (11) to the output shaft (20) by reducing a rotation speed, the magnet switch restricting rotation of the pinion (25) via connection means (90) that moves in combination with the plunger (52), pulled by the attraction coil (51), the magnet switch activating the pinion (25) by moving the movable contact (82) to contact the fixed contact (71) to activate the starter motor, wherein the magnet switch is disposed on the opposite side of the starter motor as the pinion (25).

11. A magnet switch for a starter, for providing an electric current to a starter motor by contacting a moveable contact to a fixed contact, comprising:

a case (55) made of a magnetic material;

a cylindrical electromagnetic coil (51) housed in the case (55);

a fixed iron core (54) for covering one end of the electromagnetic coil (51);

a plunger (52) that is installed in the electromagnetic coil (51) and slides therein toward the fixed iron core (54) by means of a magnetic circuit made up of the case (55) and the fixed iron core (54) when the electromagnetic coil (51) is energized;

a holding member (58) for holding the movable contact (82), the holding member (58) being installed on the fixed contact side of the fixed iron core (54); and

a connection member (90) for connecting the holding member (58) with the plunger (52) along an outer periphery of the case (55).

12. The magnet switch for starter according to claim 11, wherein said holding member (58) is formed so as to cover a part of the outer periphery of the case (55).

13. The magnet switch for starter according to claim 11, wherein said holding member (58) has a housing for housing said movable contact (82), and a contact pressure providing spring is arranged between the movable contact (82) and the housing to provide contact pressure to the movable contact (82).

14. The magnet switch for starter according to claim 11, wherein a contact pressure providing spring is arranged between the holding member and the connection member to provide contact pressure to the movable contact.

15. The magnet switch for a starter according to claim 11, adopted in a starter for moving a pinion gear (25) by rotating a starter motor while controlling, with a controlling member, rotation of the pinion gear (25), wherein the rotation of the pinion gear (25) is limited by moving the plunger (52) to move the controlling member.