Solenoid with an improved contact design and a system utilizing the solenoid

• US 5,563,563 A
• Filed: 12/04/1995
• Issued: 10/08/1996
• Est. Priority Date: 12/04/1995
• Status: Expired due to Fees

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Ford Motor Company
• Inventors: Massicotte, Mark R., Freitas, Charles M., Xue, Xiaolin B.
• Primary Examiner(s): Donovan, Lincoln
• Application Number:
  US08/566,806
• Time in Patent Office: 309 Days
• Field of Search: 335/126, 335/131
• US Class Current: 335/126
• CPC Class Codes: H01H 1/04 Co-operating contacts of different material
• 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

In one embodiment of the present invention, a starter motor solenoid includes two fixed contacts and a movable contact. The movable contact and one fixed contact are made of copper. The other fixed contact is made of steel. Over a relatively few cycles of the starter motor solenoid, a coating of copper is deposited from the movable contact to the steel fixed contact. Thus, despite the use of relatively inexpensive steel as fixed contact material, a highly-conductive and reliable junction is provided between the movable contact and the steel fixed contact.

Claims

1. A solenoid comprising:

first and second fixed contacts;

a movable contact adapted to switchably couple said first and second fixed contacts together;

wherein one of said fixed contacts is made of steel.

2. A solenoid as recited in claim 1, wherein said steel fixed contact is plated.

3. A solenoid as recited in claim 2, wherein said plating is tin plating.

4. A solenoid as recited in claim 1, wherein said movable contact is made of a material having higher electrical conductivity than steel.

5. A solenoid as recited in claim 1, wherein said movable contact is made of copper.

6. A solenoid as recited in claim 5, wherein the other said fixed contact is made of copper.

7. A solenoid as recited in claim 6, wherein said other fixed contact is plated.

8. A solenoid as recited in claim 7, wherein said other fixed contact is tin plated.

14. A cranking system for a motor vehicle, said system comprising:

an electrical power source;

a cranking motor;

a solenoid as recited in claim 1;

wherein the fixed contact made of steel is coupled to said cranking motor and the other fixed contact is coupled to said electrical power source.

15. A cranking system for a motor vehicle, said system comprising:

an electrical power source;

a cranking motor;

a solenoid as recited in claim 4;

wherein the fixed contact made of steel is coupled to said cranking motor and the other fixed contact is coupled to said electrical power source.

16. A cranking system for a motor vehicle, said system comprising:

an electrical power source;

a cranking motor;

a solenoid as recited in claim 6;

wherein the fixed contact made of steel is coupled to said cranking motor and the other fixed contact is coupled to said electrical power source.

9. A solenoid comprising:

a first fixed contact;

a second fixed contact;

a movable contact adapted to switchably couple said first and second fixed contacts together;

wherein said movable contact and one of said fixed contacts are made of different base materials.

10. A solenoid as recited in claim 9, wherein said one of said fixed contacts is made of steel.

11. A solenoid as recited in claim 10, wherein said movable contact and the other said fixed contact are made of a common material.

12. A solenoid as recited in claim 10, wherein said one of said fixed contacts is plated.

13. A solenoid as recited in claim 9, wherein said movable contact and the other said fixed contact are made of a common material.

17. A solenoid comprising:

a copper terminal stud having an integral first fixed contact;

a steel terminal stud having an integral second fixed contact; and

a copper movable contact disposed in opposition to said first and second fixed contacts for switchably coupling said first and second fixed contacts.

18. An electrical system comprising:

a battery;

a cranking motor; and

a solenoid as recited in claim 17;

wherein said steel terminal stud is electrically coupled to said cranking motor and said copper terminal stud is coupled to said battery.

19. A solenoid as recited in claim 17 wherein said terminal studs are tin plated.

20. An electrical system as recited in claim 18 wherein said terminal studs are tin plated.