Vibration damping apparatus using magnetic circuit

• US 6,505,718 B2
• Filed: 07/05/2001
• Issued: 01/14/2003
• Est. Priority Date: 07/11/2000
• Status: Expired due to Fees

• Current Assignee: Delta Tooling Co., Ltd.
• Original Assignee: Delta Tooling Co., Ltd.
• Inventors: Fujita, Etsunori, Honda, Hiroki, Oshimo, Hiroki
• Primary Examiner(s): Schwartz, Christopher P.
• Assistant Examiner(s): KRAMER, DEVON C
• Application Number:
  US09/899,623
• Publication Number:
  US 20020017749A1
• Time in Patent Office: 558 Days
• Field of Search: 257/140.14, 257/140.15, 188/378, 188/379, 188/380, 188/267, 188/267.2
• US Class Current: 188/267
• CPC Class Codes: F16F 15/03 using magnetic or electromagnetic means F16F9/53, F16F15/005 take precedence
• CPC Class Codes: F16F 3/026 to give a zero-spring rate characteristic
• CPC Class Codes: F16F 6/005 using permanent magnets only

Abstract

A vibration damping apparatus using a magnetic circuit which is easier and less expensive to manufacture than conventional apparatus is provided. The apparatus comprises a moving member 30 placed to move relatively away from and close to magnets 20 and 21 and made of a magnetic material which generates attraction force between the moving member 30 and the magnets 20 and 21, metal springs 40 and 41 as elastic members urging the moving member 30 in a direction in which the moving member 30 approaches the magnets 20 and 21, and rubbers 60 and 61 as cushioning members mounted on predetermined positions to prevent the moving member 30 from coming in contact with the magnets 20 and 21. A negative spring constant is created by using an attracting magnetic circuit formed between the magnets 20 and 21 and the moving member 30, and to this, the elastic force of the metal springs 40 and 41 having a positive spring constant with the same value as the negative spring constant is added, whereby a total spring constant within a predetermined range of displacement can be set to substantially near zero by a very simple configuration.

Claims

1. A vibration damping apparatus using a magnetic circuit, comprising:

a moving member placed to move relatively away from and close to a magnet and made of a magnetic material which generates an attraction force between said moving member and the magnet;

an elastic member urging said moving member in a direction in which said moving member approaches the magnet; and

a cushioning member mounted on a predetermined position to prevent said moving member from coming in contact with the magnet,

wherein a total spring constant obtained by a combination of the attraction force between the magnet and said moving member with an elastic force of said elastic member is sot to substantially zero within a predetermined range of displacement.

2. A vibration damping apparatus using a magnetic circuit as set forth in claim 1,

wherein said elastic member comprises a metal spring.

3. A vibration damping apparatus using a magnetic circuit as set forth in claim 1,

wherein said cushioning member comprises a rubber.

4. A vibration damping apparatus using a magnetic circuit, comprising:

a moving member placed to move relatively away from and close to a magnet and made of a magnetic material which generates an attraction force between said moving member and the magnet;

an elastic member urging said moving member in a direction in which said moving member approaches the magnet;

a cushioning member mounted on a predetermined position to prevent and moving member from coming in contact with the magnet; and

an operating member connected to and moving member and placed so that the magnet is positioned around said operating member, moving in a direction in which it traverses a magnetic flux generated in a space in the magnet with the approaching and leaving movement of said moving member, and made of a conductive material which generates a damping force by an electromagnetic inductive action,

wherein a total spring constant obtained by a combination of the attraction force between the magnet and said moving member with an elastic force of said elastic member is set to substantially zero within a predetermined range of displacement.

5. A vibration damping apparatus using a magnetic circuit as set forth in claim 4,

wherein said elastic member comprises a metal spring.

6. A vibration damping apparatus using a magnetic circuit as set forth in claim 4,

wherein said cushioning member comprises a rubber.