Magnet switch for starter

• US 6,822,544 B2
• Filed: 04/01/2003
• Issued: 11/23/2004
• Est. Priority Date: 04/03/2002
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Niimi, Masami, Shiga, Tsutomu
• Primary Examiner(s): DONOVAN, LINCOLN D
• Application Number:
  US10/403,022
• Publication Number:
  US 20030189472A1
• Time in Patent Office: 602 Days
• Field of Search: 335/126, 335/131, 290/48, 200/292
• US Class Current: 335/126
• CPC Class Codes: F02N 11/0851 characterised by means for controlling the engagement or disengagement between engine and starter, e.g. meshing of pinion and engine gear
• CPC Class Codes: F02N 11/087 Details of the switching means in starting circuits, e.g. relays or electronic switches
• CPC Class Codes: F02N 15/067 the starter comprising an electro-magnetically actuated lever
• CPC Class Codes: F02N 2011/0874 characterised by said switch being an electronic switch
• CPC Class Codes: F02N 2300/102 Control of the starter motor speed; Control of the engine speed during cranking
• 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
• CPC Class Codes: H01H 9/38 Auxiliary contacts on to which the arc is transferred from the main contacts using arcing-horns H01H9/46

Abstract

In a magnet switch for a starter, a first contact portion and a second contact portion are connected in parallel between a battery and a motor. The first contact portion makes contact through a resistive component so that the motor starts rotation at low speed. By this, a pinion is pushed in an axial direction by an axial component of splines and brought into mesh with a ring gear in a condition that its rotation is restricted. Thereafter, the second contact portion makes contact in accordance with further movement of a plunger so that electric power is fully supplied to the motor through the second contact portion, thereby starting engine. A fixed contact of the first contact portion is made of a carbon material. The resistive component is provided by the carbon material.

Claims

1. A magnet switch for a starter to supply electric power to a motor, comprising:

a first contact portion having a fixed contact and a movable contact, the first contact portion including a carbon material;

a second contact portion having a fixed contact and a movable contact, the second contact portion including a metal material, wherein the first contact portion and the second contact portion operate an electrical connection between the motor and a battery, and wherein the first contact portion and the second contact portion are disposed such that the first contact portion makes contact before the second contact portion makes contact.

2. The magnet switch according to claim 1, wherein, the first contact portion and the second contact portion are disposed such that the first contact portion breaks contact after the second contact portion breaks contact.

3. The magnet switch according to claim 1, wherein the first contact portion includes a resistive component in series in a current path, wherein the first contact portion and the second contact portion are disposed to be in a parallel circuit between the battery and the motor.

4. The magnet switch according to claim 3, wherein the carbon material includes ten percent or less metal content and provides the resistive component.

5. The magnet switch according to claim 3, wherein the carbon material includes one hundred percent carbon and provides the resistive component.

6. The magnet switch according to claim 1, further comprising a resilient member for applying a contact pressure to the first and the second contact portions.

7. The magnet switch according to claim 1, wherein:

the carbon material includes two layers, the first layer includes more metal than carbon and the second layer includes one hundred percent carbon, and

the first contact portion is disposed to make contact via the second layer before the first layer and to break contact via the first layer before the second layer.

19. The magnet switch according to claim 6, wherein

the fixed contact of the first contact portion is made of the carbon material, and

the resilient member has a first end and a second end, the moveable contact of the first contact portion is provided by the first end of the resilient member and the moveable contact of the second contact portion is disposed on the second end of the resilient member.

8. A magnet switch for a starter, comprising:

an attraction coil for generating an attraction force when excited; and

a contact unit for electrically connecting a battery and a motor, including;

a first contact portion for supplying electric power to a motor through a resistive component, the first contact portion including a movable contact and a fixed contact, one of the movable contact and the fixed contact being electrically connected to a battery and the other of the movable contact and the fixed contact being operatively coupled to a plunger that is movable by the attraction force; and

a second contact portion for supplying electric power to the motor, the second contact portion including a movable contact comprised of a metal and a fixed contact comprised of a metal, one of the movable contact and the fixed contact being electrically connected to the battery and the other of the movable contact and the fixed contact being operatively coupled to the plunger,

wherein the contact unit is disposed such that the movable contact and the fixed contact of the first contact portion are brought into contact with each other while bending a return spring by the plunger to supply the electric power to the motor through the resistive component before the movable contact and the fixed contact of the second contact portion are brought into contact with each other by further movement of the plunger to supply the electric power to the motor, and when the power supply to the attraction coil is turned off, the movable contact and the fixed contact of the second contact portion are separated before the movable contact and the fixed contact of the first contact portion are separated by a return force of the return spring, and

wherein the resistive component is provided by a contact of the first contact portion, the contact being made of a carbon material.

9. The magnet switch according to claim 8, wherein the contact unit includes a resilient member for applying contact pressure to the first contact portion and the second contact portion.

10. The magnet switch according to claim 8, wherein the fixed contacts of the first and second contact portions are disposed to be connected to the battery, and the movable contacts of the first and second contact portions and the resilient member are disposed adjacent to the plunger.

11. The magnet switch according to claim 9,

wherein the resilient member includes a resilient part for applying contact pressure to the contact made of the carbon material by its resiliency in accordance with the movement of the plunger, to gradually increase the contact pressure from zero to a predetermined pressure after the power supply to the attraction coil is started and gradually decreasing the contact pressure from the predetermined pressure to zero after the power supply to the attraction coil is cut off.

12. The magnet switch according to claim 8,

wherein the carbon material includes two layers, the first layer is made of carbon and metal and the second layer is made of carbon, and

wherein the first contact portion is disposed to make contact via the second layer before the first layer while the first contact portion is closed, and to break contact via the first layer before the second layer while the first contact portion opens.

13. The magnet switch according to claim 8, wherein:

the plunger is disposed to restrict rotation of a pinion, which is supported on an output shaft coupled to an armature shaft of the motor, through a connecting means while moved by the attraction force,

the first contact portion has the contact made of carbon material that provides a resistance against the power supplied to the motor so that the pinion is pushed through helical splines formed the output shaft and brought into mesh with a ring gear of an engine, and

the second contact portion allows the power to the motor so that rotation of the motor is transmitted to the output shaft through a speed reducing device, thereby starting the engine.

20. The magnet switch according to claim 9, wherein

the resilient member has a U-shape having a first end and a second end and is moveable with the movement of the plunger, and

the movable contact of the first contact portion is provided at the first end of the resilient member as a part of the resilient member and the moveable contact of the second contact portion is fixed to the second end of the resilient member.

14. A magnet switch for a starter to supply electric power to a motor, the magnet switch comprising:

a first contact portion including a fixed contact and a movable contact for electrically connecting the motor and a battery, one of the fixed contact and the movable contact being made of a carbon material; and

a second contact portion including a fixed contact comprised of a metal and a movable contact comprised of a metal, the second contact portion connected in parallel with the first contact portion between the battery and the motor,

wherein the first contact portion is disposed to make contact before the second contact.

15. The magnet switch according to claim 14, wherein the carbon material includes ninety percent or more carbon, thereby providing a resistance in a circuit.

16. The magnet switch according to claim 14, further comprising:

an attraction coil for generating attraction force when excited; and

a plunger movable by the attraction force,

wherein the movable contacts of the first and the second contact portions are operatively coupled to the plunger,

wherein the first contact portion makes contact before the second contact portion in accordance with movement of the plunger.

17. The magnet switch according to claim 16, further comprising:

a resilient member for applying contact pressure to the first contact portion in accordance with the movement of the plunger,

wherein the resilient member gradually increases the contact pressure from zero to a predetermined pressure when the power supply to the attraction coil is started and gradually decreases the contact pressure to zero when the power supply to the attraction coil is cut off.

18. The magnet switch according to claim 14,

wherein the fixed contact of the first contact portion is made of the carbon material, the carbon material is formed into two layers, and the first layer includes less carbon than the second layer,

wherein the first contact portion is arranged such that the movable contact makes contact with the second layer before the first layer while the first contact portion is closed and the movable contact separates from the first layer before the second layer while the first contact portion opens.

21. The magnet switch according to claim 18, further comprising a resilient member having a first end and a second end, wherein the movable contact of the first contact portion is provided by the first end of the resilient member and the movable contact of the second contact portion is connected to the second end of the resilient member.