JP4760485B2 - Strain detector - Google Patents

Description

  The present invention relates to a strain detection device for measuring a load on a vehicle seat or the like.

  Hereinafter, a conventional strain detection apparatus will be described.

  In FIG. 7, the conventional strain detection device is arranged between a plate-shaped metal strain generating body 32 having a plurality of through holes 31 and a through hole 31 of the strain generating body 32, and has resistance according to the amount of strain. A resistance element 33 whose value changes and a signal processing circuit (not shown) connected to the resistance element 33 are provided.

  For example, if the strain detection device is attached between the vehicle seat and the floor portion, the load of the person sitting on the vehicle seat can be measured. A part of the vehicle seat is inserted into the inner through-hole 31 among the plurality of through-holes 31 provided in the strain-generating body 32 to connect the strain-generating body 32 and the vehicle seat. A part of the floor surface portion is inserted and the strain generating body 32 and the floor surface portion are connected and attached (for example, a part of the vehicle seat or a part of the floor surface portion is used as a screw portion, and the nut is formed via the strain generating body 32. Tighten with and attach). Then, when a load is applied to the vehicle seat, the strain body 32 is distorted and the resistance value of the resistance element 33 changes, and the load can be measured by processing this with a signal processing circuit. In this case, since the strain body 32 is connected to both the vehicle seat and the floor portion, the load in the compression direction and the load in the tension direction can be measured. In the signal processing circuit, four resistance elements 33 are annularly connected to form a Hoyston bridge circuit and input to the signal processing circuit.

  As the shape of the strain generating body 32, there is a cylindrical shape in addition to the plate shape, and both are those in which a strain detecting device is attached by combining a plurality of attachment parts.

As prior art document information related to the invention of this application, for example, Patent Document 1 and Patent Document 2 are known.
JP 2003-240633 A JP-A-6-207865

  The above-described conventional strain detection device has a problem in that a plurality of mounting parts are required for mounting the strain detection device, and the assembly work efficiency and usability are poor.

  SUMMARY OF THE INVENTION The present invention solves the above-described problems, and an object of the present invention is to provide a strain detection device that has few attachment parts and is easy to work and easy to use.

  In order to achieve the above object, the present invention provides a columnar strain generating body that generates strain due to a load, a screw portion disposed in an axial direction of the strain generating body so as to sandwich the strain generating body, A first output electrode and a second output electrode disposed on the circumferential surface and opposed to each other, and a power supply electrode and a ground electrode disposed on the circumferential surface of the strain generating body and opposed to the first and second output electrodes. And first and second resistance elements connected to the power supply electrode and the first and second output electrodes, respectively, and third and fourth connected to the ground electrode and the first and second output electrodes, respectively. A first resistive element, a first resistive element, a first resistive element, a first resistive element, a first resistive element, a first resistive element, a first resistive element, and a grounding electrode, and The second output electrode, the power supply electrode, and the ground electrode are covered with a strain resistor. It is then formed by configuration.

  With the above configuration, since the screw part is arranged in the axial direction of the strain generating body so as to sandwich the strain generating body, it can be easily attached by connecting, for example, the seat and the floor surface part through this screw part. Thus, the work efficiency and usability can be improved.

  In particular, the first to fourth strain resistance elements, except for the facing portion between the power supply electrode and the ground electrode, between the first output electrode and the second output electrode, the first, second output electrode, the power supply electrode, Since the ground electrode is formed by covering the strain resistor, since all the electrodes are covered by the strain resistor, electrode corrosion caused by moisture or the like can be suppressed. At this time, since the strain resistor is covered between the first output electrode and the second output electrode except for the facing portion between the power electrode and the ground electrode, the strain is interposed between the power electrode and the ground electrode. No resistance component is added, and characteristic deterioration can be suppressed.

  Hereinafter, the invention described in all claims of the present invention will be described with reference to the drawings.

  1 is a perspective view of a strain detection device according to an embodiment of the present invention, FIG. 2 is a development view of a circumferential surface of a strain generating body of the strain detection device, FIG. 3 is a sectional view of the strain detection device, and FIG. 5 is a side view of a seat unit in which a vehicle seat and a floor portion are connected via a strain detection device, FIG. 5 is an enlarged view of a portion A in FIG. 4, and FIG. 6 is a front sectional view of the portion A in FIG.

  1 to 3, a strain detection apparatus according to an embodiment of the present invention includes a columnar strain generating body 2 that generates strain due to a load, and a resistance that is arranged on the outer peripheral surface of the strain generating body 2 according to the amount of strain. Signal processing for detecting the strain amount of the strain generating body 2 connected to the first to fourth resistance elements 4a, 4b, 4c, and 4d whose values change and the first to fourth resistance elements 4a, 4b, 4c, and 4d. Circuit (not shown). The strain body 2 has a cylindrical shape having a cavity 8 in the axial direction, and a screw portion 10 is arranged in the axial direction of the strain body 2 so as to sandwich the strain body 2. 10 are welded and joined together.

  Further, as shown in FIG. 2, the first output electrode 5a and the second output electrode 5b disposed on the circumferential surface of the strain generating body 2 and opposed to each other, and the first output electrode 5a and the second output electrode 5b disposed on the circumferential surface of the strain generating body 2 The power supply electrode 7 and the ground electrode 9 are opposed to the second output electrodes 5a and 5b, and are connected to the pad electrode 6, respectively. The first and second output electrodes 5a and 5b, the power supply electrode 7 and the ground electrode 9 are linear Ag electrodes formed by baking silver, and the opposing direction of each electrode is defined as the axial direction of the strain generating body 2. Yes. The power supply electrode 7 and the ground electrode 9 are arranged on substantially the same straight line, the first and second output electrodes 5a and 5b and the power supply electrode 7 are arranged substantially in parallel, and the first and second output electrodes 5a and 5b. And the power supply electrode 7 is arrange | positioned substantially parallel.

  Further, the first and second resistance elements 4a and 4b are formed by connecting the ground electrode 9 and the first and second output electrodes 5a and 5b, respectively, and the third and fourth resistance elements 4c and 4d are the power supply electrodes 7 respectively. And the first and second output electrodes 5a and 5b are connected to each other. The first to fourth resistance elements 4 a, 4 b, 4 c, and 4 d are provided between the opposed portions 17 of the first output electrode 5 a and the second output electrode 5 b except for the opposed portion 11 between the power supply electrode 7 and the ground electrode 9. The first and second output electrodes 5a and 5b, the power supply electrode 7 and the ground electrode 9 are formed by covering a strain resistor.

  The strain detection device applies a predetermined voltage between the pad electrode 6 (VCC) connected to the power supply electrode 7 and the pad electrode 6 (GND) connected to the ground electrode 9 to thereby generate the first output electrode. Signals are output from the pad electrode 6 (V +) connected to 5a and the pad electrode 6 (V-) connected to the second output electrode 5b.

  If this strain detection device is attached between the vehicle seat 12 and the floor surface portion 14 as shown in FIGS. 4 to 6, for example, the load of a person sitting on the vehicle seat 12 can be measured. The vehicle seat 12 is provided with an attachment portion 13 as an attachment member at a lower portion thereof, and the attachment portion 13 is provided with a through hole into which the screw portion 10 is inserted. The floor surface portion 14 is provided with a support portion 22 as an attachment member on the floor surface 18, and the support portion 22 is provided with a through hole into which the screw portion 10 is inserted. The axial direction of each through hole of the attachment portion 13 and the support portion 22 is set to be horizontal with respect to the floor surface 18.

  Then, one screw portion 10 is inserted into the through hole of the attachment portion 13 of the vehicle seat 12, and the other screw portion 10 is inserted into the through hole of the support portion 22, and tightened with the nuts 20 that are fastening members. The vehicle seat 12 and the floor surface portion 14 are connected via the strain body 2 and the screw portion 10.

  In the above strain detection device, when a load is applied to the vehicle seat 12, the screw portion 10 is arranged so that the load direction is perpendicular to the axial direction of the strain generating body 2 (up and down direction with respect to the floor surface 18). A load is added. At this time, since the elastic member 15 is disposed between the one attachment portion 13 and the strain body 2 and is fastened and fixed, a bending moment is generated in the strain body 2 so that the strain can be accurately detected. it can. Simply, when a load is applied to the screw portion 10 so that the load direction is perpendicular to the axial direction of the strain generating body 2, the strain is generated due to the shearing force or bending moment of the strain generating body 2. Although the body 2 is distorted, the amount of strain associated with a bending moment having a large amount of strain can be detected by the above configuration.

  In particular, the height between the vehicle seat 12 and the floor surface portion 14 can be reduced by simply selecting the diameter of the strain generating body 2 according to the specifications, and the vehicle seat 12 varies depending on the vehicle type. The seat height can be set low beforehand. That is, it becomes easy to adjust the height of the line of sight of the person sitting on the seating surface.

  Since the screw part 10 is formed so as to sandwich the strain generating body 2 with the above configuration, for example, when the vehicle seat 12 and the floor surface part 14 are connected via the screw part 10, an attachment component is provided. It can be installed with little and simple, and the work efficiency and usability can be improved.

  In particular, the first to fourth resistance elements 4 a, 4 b, 4 c, and 4 d have a distance 17 between the first output electrode 5 a and the second output electrode 5 b except for the facing portion 11 between the power supply electrode 7 and the ground electrode 9. The first and second output electrodes 5a and 5b, the power supply electrode 7 and the ground electrode 9 are formed by covering a strain resistor, and all the electrodes are covered with the strain resistor, so that the electrodes are caused by moisture or the like. Corrosion can be suppressed.

  Usually, a protective glass layer is provided on the first and second output electrodes 5a and 5b, the power supply electrode 7, the ground electrode 9, and the first to fourth resistance elements 4a, 4b, 4c, and 4d. Since porous or the like occurs, if there is an electrode that is not covered with the first to fourth resistance elements 4a, 4b, 4c, and 4d that are strain resistors, moisture permeates and causes electrode corrosion (migration, etc.). However, according to the above configuration, the first to fourth resistance elements 4a, 4b, 4c, all of which are electrodes (first and second output electrodes 5a, 5b, power supply electrode 7, ground electrode 9) are strain resistors. Since it is covered with 4d, electrode corrosion is suppressed.

  At this time, since the opposing portion 17 between the first output electrode 5a and the second output electrode 5b is covered with the strain resistor except for the facing portion 11 between the power electrode 7 and the ground electrode 9, the power electrode 7 No distortion resistance component is added between the ground electrode 9 and the characteristic deterioration can be suppressed.

  Furthermore, since the strain body 2 and the screw portion 10 are integrated with each other, the breakage at the boundary between the strain body 2 and the screw portion 10 can be suppressed even when a load is applied to the vehicle seat 12. From several tens of kg at the time of weight detection to about 1 ton at the time of vehicle collision detection, breakage at the boundary between the strain generating body 2 and the screw portion 10 can be suppressed without impairing the detection capability, and the vehicle can be destroyed. The breakage at the boundary between the strain body 2 and the screw portion 10 can be suppressed even with a load of several tons.

  The strain body 2 and the threaded portion 10 may be welded and joined together, or members made of the same material may be processed. Examples of the material of the strain body 2 and the screw portion 10 include precipitation hardening stainless steel. When the strain body 2 and the screw portion 10 are made of the same material, SUS630 and the like can be cited. Other examples include SUS301 having austenitic work-hardening properties that are rich in ductility and toughness and excellent in weldability, and ferrite-based SUS430 having good corrosion resistance and weldability. These SUS630, SUS301, and SUS430 are stainless steel standards defined by Japanese Industrial Standards (JIS).

  The strain resistor in one embodiment of the present invention is formed by firing a resistor paste made of metal glaze and is not a mere resin-based insulating layer. Therefore, a resin-based material is used as a protective layer. In the case of water leakage, water penetration can be removed. In particular, when glass is used as the protective layer, since the firing temperature of the glass is 850 degrees, the material of the strain generating body 2 cannot use an austenite or martensite system having a transformation point of 720 degrees or less, The degree of freedom in design is limited to ferrites with high temperature durability, but the degree of freedom in design can be improved by adopting the above configuration.

  As described above, the strain detection device according to the present invention has few attachment parts, is easy to install, has good work efficiency and convenience, and can be applied to various devices as a sensor for measuring a load.

The perspective view of the distortion | strain detector in one embodiment of this invention Development view of the peripheral surface of the strain body of the strain detector Cross section of the strain detector Side view of a seat unit in which a vehicle seat and a floor surface portion are connected via the strain detection device Enlarged view of part A in FIG. Front sectional view of part A in FIG. Top view of a conventional strain detector

Explanation of symbols

2 strain generating body 4a 1st resistance element 4b 2nd resistance element 4c 3rd resistance element 4d 4th resistance element 5a 1st output electrode 5b 2nd output electrode 6 Pad electrode 7 Power supply electrode 8 Cavity 9 Ground electrode 10 Screw part 11 Opposite Part 12 vehicle seat 13 mounting part 14 floor part 15 elastic member 16 rail part 18 floor 20 nut 22 support part

Claims (3)

A columnar strain generating body that generates strain due to a load, a screw portion that is disposed in the axial direction of the strain generating body so as to sandwich the strain generating body, and a circumferentially disposed surface of the strain generating body and that are opposed to each other A first output electrode and a second output electrode; a power supply electrode and a ground electrode disposed on a circumferential surface of the strain generating body and opposed to the first and second output electrodes; and the power supply electrode and the first and second output electrodes. First and second resistance elements connected to two output electrodes, and third and fourth resistance elements connected to the ground electrode and the first and second output electrodes, respectively. The four-resistance element is configured such that the first output electrode and the second output electrode are opposed to each other, except for the facing portion between the power electrode and the ground electrode, the first and second output electrodes, the power electrode, A strain detection device formed by covering a ground electrode with a strain resistor. The first and second output electrodes, the power supply electrode, and the ground electrode are linear, and the power supply electrode and the ground electrode are arranged on substantially the same straight line, and the first, second output electrode, and the ground electrode The strain detection device according to claim 1, wherein the power supply electrode is disposed substantially parallel to each other, and the first and second output electrodes and the ground electrode are disposed substantially parallel to each other. The strain detection apparatus according to claim 1, wherein a facing direction of the first and second output electrodes, the power supply electrode, and the ground electrode is an axial direction of the strain generating body.

Images