Load sensor equipped with strain-generating member having strain elements with tube spacer for eliminating clamping force

• US 6,677,539 B2
• Filed: 09/12/2001
• Issued: 01/13/2004
• Est. Priority Date: 09/18/2000
• Status: Expired due to Fees

• Current Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.), Takata Corporation (Ningbo Junsheng Investment Group Co., Ltd.)
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Aoki, Hiroshi, Miura, Akito, Shimbo, Kunio, Takahashi, Koichi
• Primary Examiner(s): GIBSON, RANDY W
• Application Number:
  US09/954,668
• Publication Number:
  US 20020033283A1
• Time in Patent Office: 853 Days
• Field of Search: 180/273, 280/735, 701/45, 340/667, 177/25.11, 177/25.13, 177/136, 177/144, 177/210.R, 177/211, 177/229, 177/DIG.9, 738/624.74, 738/626.32
• US Class Current: 177/136
• CPC Class Codes: G01G 19/4142 for controlling activation of safety devices, e.g. airbag systems electrical circuits for triggering safety arrangements in case of vehicle accidents B60R21/015
• CPC Class Codes: G01G 23/002 Means for correcting for obliquity of mounting for pendulum-weight apparatus G01G1/16
• CPC Class Codes: G01L 1/2206 Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
• CPC Class Codes: Y10S 177/09 Scale bearings

Abstract

A load sensor is assembled by screwing a nut on a bolt, sequentially fitting a washer and a tube spacer on the bolt, fitting a bore of a strain-generating member on the tube spacer, fitting another washer on the bolt, tightening another nut, and clamping a bobbin-shaped unit composed of the washers and the tube spacer between the nuts in the axial direction of the bolt. Since the strain-generating member having a thickness less than the height of a strain-generating member holding space formed between the washers is placed in the space with some clearance, even when the washers are fixed to the bolt by a strong pressing force, the pressing force will not directly act on the strain-generating member.

Claims

1. A load sensor comprising:

a strain-generating member having a bore formed at a distance from a load point on which a load acts;

a strain element mounted on said strain-generating member between said load point and said bore;

a fixed shaft for supporting said strain-generating member; and

a spacer member fixed to said fixed shaft,

wherein said spacer member has a shaft portion to be passed through said bore of said strain-generating member, and a flange portion extending from said shaft portion along the surface of said strain-generating member, and a strain-generating member holding space is formed between said flange portion and the rim of said bore so as to extend in the axial direction of said fixed shaft.

2. A load sensor according to claim 1, wherein said fixed shaft is a threaded bolt, and said spacer member is fixed by nuts fastened to said bolt.

3. A load sensor according to claim 2, wherein said spacer member includes a tube spacer having a length greater than the thickness of said strain-generating member so as to be passed through said bore, and a pair of washers for clamping said tube spacer by said nuts.

4. A load sensor according to claim 2, said spacer member includes a pair of convex washers each having a cylindrical portion at the center thereof, said cylindrical portions of said washers are clamped by said nuts, and said bore of said strain-generating member is fitted on said cylindrical portions.

5. A load sensor according to claim 1, wherein the thickness of a portion of said strain-generating member adjacent to said bore is set to be greater than the thickness of a portion of said strain-generating portion where said strain element is mounted.

6. A load sensor according to claim 1, wherein said strain-generating member holding space is filled with a fixing adhesive.

7. A load sensor comprising:

a strain-generating member having a bore formed at a distance from a load point on which a load acts;

a strain element mounted on said strain-generating member between said load point and said bore;

a fixed shaft passed through said bore of said strain-generating member;

a pair of spacer members fitted on said fixed shaft with said strain-generating member therebetween; and

fixing means for fixing said spacer members by pressing said spacer members in the axial direction of said fixed shaft,

wherein a concave or convex pressed portion is formed at a predetermined position on the periphery of said bore of said strain-generating member, said pressed portion is clamped between said spacer members, and the front and back surfaces of said strain-generating member except said pressed portion are held spaced from said spacer members.