Electromagnetic valve device and manufacturing method thereof

• US 20030116739A1
• Filed: 12/12/2002
• Published: 06/26/2003
• Est. Priority Date: 12/13/2001
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Kawabata, Sanemasa, Murao, Yoshiyuki, Sumiya, Hiroshi, Kawamura, Futoshi
• Granted Patent: US 6,722,627 B2
• Time in Patent Office: Days
• US Class Current: 251/129.15
• CPC Class Codes: F16K 31/0613 with cylindrical slides
• CPC Class Codes: F16K 31/0668 Sliding valves
• CPC Class Codes: H01F 7/081 Magnetic constructions
• CPC Class Codes: H01F 7/1607 Armatures entering the winding
• CPC Class Codes: Y10T 137/7036 Jacketed

Abstract

An electromagnetic valve device reduces wear of a moving member and a non-magnetic member sliding against the moving member and prevents foreign matter from contacting the sliding part. The moving member is directly and movably supported in a reciprocating manner by a non-magnetic cup. The moving member has a hard layer made of nickel containing PTFE (polytetrafluoroethylene) particles at the sliding part located against the cup. The hardness of the hard layer is high and is approximately the hardness of the stainless steel cup. Therefore, the wear of both the moving member and the cup can be reduced. The hard layer contains the PTFE particles, and therefore the sliding part between the moving member and the cup is lubricated by the PTFE, which reduces the sliding resistance at the sliding part and improves the responsiveness of the device.

Claims

1. An electromagnetic valve device, comprising:

a moving member;

a valve member reciprocating together with said moving member, for controlling a flow rate of a fluid passing through a fluid path;

an energizing means for energizing said moving member in a first reciprocating direction;

a coil portion for generating a magnetic force to attract said moving member in a second reciprocating direction;

a stator for forming a magnetic circuit with said moving member, the stator having a tube portion covering an outer periphery of said moving member and a suction portion forming a gap between said tube portion and itself in the first and second reciprocating directions of said moving member, the suction member attracting said moving member in the second reciprocating direction; and

a non-magnetic member provided at an inner circumference of said tube portion, for movably supporting said moving member in a reciprocating manner, the non-magnetic member covering an end of said moving member in one of the reciprocating directions, the non-magnetic member extending to said suction portion to cover an outer periphery of said suction portion, wherein

said moving member has a hard portion with a hardness close to a hardness of said non-magnetic member at a sliding part against said non-magnetic member.

2. The electromagnetic valve device according to claim 1, wherein

said hard portion comprises a metal layer containing a solid lubricating material.

3. The electromagnetic valve device according to claim 2, wherein

said solid lubricating material is particulate and made of fluororesin.

4. The electromagnetic valve device according to claim 3, wherein

the particles made of said fluororesin are contained in said hard portion in the range from 5 vol % to 40 vol %.

5. The electromagnetic valve device according to claim 4, wherein

said fluororesin is polytetrafluoroethylene.

6. The electromagnetic valve device according to claim 2, wherein

said solid lubricating material is molybdenum disulfide.

7. The electromagnetic valve device according to claim 2, wherein

the metal forming said metal layer is nickel.

8. The electromagnetic valve device according to claim 7, wherein

said non-magnetic material has a bottom-closed tube portion supporting said moving member at an inner circumferential location of said tube portion, a large diameter portion formed to have a diameter larger than that of said bottom-closed tube portion, and a tapered portion connecting said bottom-closed tube portion and said large diameter portion.

9. The electromagnetic valve device according to claim 8, wherein

said moving member is formed to have an axial length larger than an axial length of said bottom-closed tube portion, and

when a movement amount of said moving member in said first direction is maximum, the moving member has an end, near an end of said valve member, positioned closer to a bottom portion of said bottom-closed tube portion than to a joint between said bottom-closed tube portion and said tapered portion.

10. The electromagnetic valve device according to claim 9, wherein

said suction portion is tapered with an outer diameter that increases from said moving member end portion toward said valve member, and

the outer wall of said suction portion and the inner wall of said large diameter portion define a gap.

11. A method of manufacturing an electromagnetic valve device comprising the steps of:

forming a moving member into a prescribed shape;

forming a hard portion on a surface of said moving member by electroless plating, said hard portion having a hardness approximate to that of a non-magnetic encasing portion of said moving member and containing a solid lubricating material; and

grinding a surface of said hard portion formed on said moving member.