WO2019159512A1 - Load sensor and load detection device - Google Patents

Load sensor and load detection device Download PDF

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Publication number
WO2019159512A1
WO2019159512A1 PCT/JP2018/045258 JP2018045258W WO2019159512A1 WO 2019159512 A1 WO2019159512 A1 WO 2019159512A1 JP 2018045258 W JP2018045258 W JP 2018045258W WO 2019159512 A1 WO2019159512 A1 WO 2019159512A1
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WO
WIPO (PCT)
Prior art keywords
circle
strain
load
resistor
load sensor
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Application number
PCT/JP2018/045258
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French (fr)
Japanese (ja)
Inventor
公宏 横山
朋子 海老沢
Original Assignee
アルプスアルパイン株式会社
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Application filed by アルプスアルパイン株式会社 filed Critical アルプスアルパイン株式会社
Priority to JP2020500297A priority Critical patent/JPWO2019159512A1/en
Publication of WO2019159512A1 publication Critical patent/WO2019159512A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01G—WEIGHING
    • G01G3/00—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances
    • G01G3/12—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances wherein the weighing element is in the form of a solid body stressed by pressure or tension during weighing
    • G01G3/14—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances wherein the weighing element is in the form of a solid body stressed by pressure or tension during weighing measuring variations of electrical resistance
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
    • G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges

Definitions

  • the present invention relates to a load sensor and a load detection device.
  • load sensors using strain gauges have been used.
  • a load sensor a sensor in which a bridge circuit is formed by four strain gauges arranged on a strain generating body, and a load is detected by an output voltage of the bridge circuit is known.
  • the conventional load sensor has a problem that when the direction in which the load is applied is not perpendicular to the strain generating body, the strain of the strain generating body is biased and the load detection accuracy is lowered.
  • the present invention has been made in view of the above-described problems, and an object thereof is to improve the detection accuracy of a load sensor having a strain gauge.
  • a load sensor includes a strain generating body provided with a load receiving portion, an insulating layer provided on the strain generating body, and a first resistance portion provided on the insulating layer and connected in series. And a first output terminal that outputs a voltage between the first resistance part and the second resistance part, wherein the first resistance part is connected in series and is a circle or an ellipse
  • a plurality of first strain gauges arranged on the circumference of the first circle, and the second resistance portion is connected in series and arranged on the circumference of the second circle that is a circle or an ellipse.
  • a plurality of second strain gauges are provided, and the first circle and the second circle are concentric circles or concentric ellipses around the load receiving portion.
  • the detection accuracy of a load sensor having a strain gauge can be improved.
  • FIG. 1 The top view which shows an example of the load sensor 100.
  • FIG. The side view which shows an example of the load sensor 100.
  • FIG. The elements on larger scale which show an example of the leg part 5 of FIG. Sectional drawing of the leg part 5 of FIG.
  • a load sensor 100 according to the first embodiment will be described with reference to FIGS.
  • the load sensor 100 according to the present embodiment is a sensor that detects an applied load, and includes a strain gauge.
  • a strain gauge is an element whose resistance value changes according to the strain.
  • FIG. 1 is a plan view showing an example of the load sensor 100.
  • FIG. 2 is a side view showing an example of the load sensor 100.
  • the top, bottom, left, and right in the figure will be described as the top, bottom, left, and right of the load sensor 100.
  • the load sensor 100 includes a strain body 1, an insulating layer 2, a first resistor R 1, a second resistor R 2, a third resistor R 3, and a fourth resistor.
  • a section R4, a first output terminal T1, a first output terminal T2, and a conversion circuit 3 are provided.
  • the strain body 1 is a plate-like member to which a load is applied, and is formed of a metal plate.
  • the load sensor 100 detects a load applied to the strain body 1 by detecting strain of the strain body 1 using a strain gauge. As shown in FIG. 1, the strain body 1 includes a first portion 11 and a second portion 12.
  • the first portion 11 is a circular portion that is distorted according to the load.
  • the first portion 11 has a plurality of openings 13 on the outer peripheral portion, and the outer peripheral portion is fixed to a load detection target by inserting a bolt through each opening 13.
  • a load receiver 14 that receives a load from the detection target is provided at the center of the first portion 11. In this way, by fixing the outer peripheral portion of the circular first portion 11 and applying a load at the center, the distortion of the first portion 11 according to the load can be made uniform.
  • the load receiving portion 14 is a nut having a hemispherical head, is provided on the lower surface of the strain body 1, and is inserted with a screw 15 provided on the upper surface of the strain body 1.
  • the load receiver 14 may be provided on the upper surface of the strain body 1 or may be fixed by a nut. In the latter case, a bolt having a hemispherical head may be used as the load receiving portion 14.
  • the second portion 12 is a substantially rectangular portion extending from the first portion 11.
  • the shape of the second portion 12 can be arbitrarily designed.
  • the insulating layer 2 is an insulating layer provided on the strain body 1.
  • the insulating layer 2 may be an oxide film, a nitride film, or a resin insulating film formed on the strain generating body 1, or an insulating printed board fixed on the strain generating body 1. Also good.
  • the printed circuit board may be a flexible board or a rigid board. In any case, the entire surface of the insulating layer 2 is fixed to the strain generating body 1 so as to be distorted according to the strain of the strain generating body 1.
  • the insulating layer 2 has a first portion 21 and a second portion 22.
  • the first portion 21 is a circular portion that is distorted according to the load.
  • the first portion 21 is fixed to the first portion 11 of the strain body 1 so that the center thereof coincides with the first portion 11.
  • the first portion 11 is provided with a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4.
  • an opening for inserting the screw 15 is provided at the center of the first portion 21.
  • the second portion 22 is a substantially rectangular portion extending from the first portion 21.
  • the shape of the second portion 22 can be arbitrarily designed.
  • the second portion 22 is provided from the first portion 11 to the second portion 12 of the strain body 1.
  • the conversion circuit 3 is provided in the second portion 22 on the second portion 12 of the strain generating body 1.
  • FIG. 3 is a diagram illustrating an example of a circuit configuration of the load sensor 100.
  • the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the first output terminal T1, and the first resistor A two-output terminal T2 and a conversion circuit 3 are provided on the insulating layer 2.
  • the first resistor R1 has one end connected to the power supply and the other end connected to the first output terminal T1.
  • the second resistor unit R1 has one end connected to the first output terminal T1 and the other end connected to the ground. That is, the first resistor R1 and the second resistor R2 are connected in series to form a half bridge circuit.
  • a voltage between the first resistor R1 and the second resistor R2 (a voltage obtained by dividing the power supply voltage Vdd by the first resistor R1 and the second resistor R2) is output from the first output terminal T1 as the output voltage V1. Is output.
  • the first output terminal T ⁇ b> 1 is connected to the conversion circuit 3, and the output voltage V ⁇ b> 1 is input to the conversion circuit 3.
  • the third resistor R3 has one end connected to the power supply and the other end connected to the second output terminal T2.
  • the fourth resistor unit R4 has one end connected to the second output terminal T2 and the other end connected to the ground. That is, the third resistor unit R3 and the fourth resistor unit R4 are connected in series to form a half bridge circuit.
  • a voltage between the third resistor R3 and the fourth resistor R4 (a voltage obtained by dividing the power supply voltage Vdd by the third resistor R3 and the fourth resistor R4) is output from the second output terminal T2 as an output voltage V2. Is output.
  • the second output terminal T2 is connected to the conversion circuit 3, and the output voltage V2 is input to the conversion circuit 3.
  • the third resistor R3 and the fourth resistor R4 are connected in parallel with the first resistor R1 and the second resistor R2, and are bridged together with the first resistor R1 and the second resistor R2. Configure the circuit.
  • each of the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 includes a plurality of strain gauges, and the resistance value changes according to the load.
  • the output voltage V1 becomes a voltage according to the resistance values of the first resistance part R1 and the second resistance part R2 that have changed according to the load.
  • the output voltage V2 becomes a voltage according to the resistance values of the third resistor portion R3 and the fourth resistor portion R4 that have changed according to the load. That is, the output voltages V1, V2 are both voltages according to the load.
  • the conversion circuit 3 is a circuit that detects a load based on the output voltages V1 and V2. Specifically, the conversion circuit 3 converts the difference between the output voltages V1 and V2 into a load with reference to a table prepared in advance. In the example of FIG. 3, it is assumed that the conversion circuit 3 is one IC (Integrated Circuit), but the conversion circuit 3 may be configured by a plurality of discrete components.
  • the first resistance portion R1 includes four first strain gauges r1 connected in series by printed wiring (not shown).
  • the first strain gauge r1 may be formed by printing a resistance material in which a metal material or carbon is mixed with a binder resin on the insulating layer 2, or formed by sticking a metal foil to the insulating layer 2. Also good.
  • the first strain gauge r1 may be an independent element mounted on the insulating layer 2. In any case, the entire surface of the first strain gauge r1 is fixed to the strain generating body 1 so as to be distorted according to the strain of the insulating layer 2.
  • the strain body 1 when a load is applied to the strain body 1, the strain body 1 is distorted according to the load, the insulation layer 2 is distorted together with the strain body 1, and the first strain gauge r1 is strained together with the insulation layer 2.
  • the resistance value of each first strain gauge r1 changes according to the strain, and the resistance value of the first resistance unit R1 changes according to the change of the resistance value of each first strain gauge r1.
  • the output voltage V1 changes according to the load.
  • the first strain gauges r1 are arranged at equal intervals (every 90 °) on the circumference of the first circle centered on the center of the strain body 1 (load receiving portion 14). By disposing each first strain gauge r1 in this way, it is possible to suppress an error in the resistance value of the first resistance portion R1 that occurs when the direction of the load is inclined (not perpendicular) to the strain generating body 1. This is because the strain of the first strain gauge r1 disposed on the side opposite to the tilt direction is decreased at the same time as the strain of the first strain gauge r1 disposed on the tilt direction side of the load is increased. By suppressing the error of the first resistance unit R1, the error of the output voltage V1 can be suppressed.
  • the 1st resistance part R1 should just be provided with the some 1st strain gauge r1, and the number is not restricted to four.
  • the first strain gauges r1 are preferably arranged at equal intervals on the circumference of the first circle. However, it is possible not to arrange the first strain gauges r1 at equal intervals.
  • the second resistance portion R2 includes four second strain gauges r2 connected in series by printed wiring (not shown).
  • the second strain gauge r ⁇ b> 2 may be formed by printing a metal material on the insulating layer 2, or may be formed by attaching a metal foil to the insulating layer 2.
  • the second strain gauge r2 may be an independent element mounted on the insulating layer 2. In either case, the entire surface of the second strain gauge r2 is fixed to the strain generating body 1 so as to be distorted in accordance with the strain of the insulating layer 2.
  • the strain generating body 1 when a load is applied to the strain generating body 1, the strain generating body 1 is strained according to the load, the strain generating body 1 and the insulating layer 2 are strained, and the insulating layer 2 and the second strain gauge r2 are strained.
  • the resistance value of each second strain gauge r2 changes according to the strain, and the resistance value of the second resistance portion R2 changes according to the change of the resistance value of each second strain gauge r2.
  • the output voltage V1 changes according to the load.
  • the second strain gauges r2 are arranged at equal intervals (every 90 °) on the circumference of the second circle with the center of the strain generating body 1 as the center.
  • the second circle is a concentric circle of the first circle smaller than the first circle.
  • the outer peripheral portion of the first portion 11 is fixed, when a load is applied to the strain generating body 1, the central portion side and the outer peripheral portion side of the first portion 11 are distorted in opposite directions.
  • the resistance value of the gauge r2 changes in the opposite direction. That is, when a load is applied to the strain body 1, the resistance value of the first resistance part R1 and the resistance value of the second resistance part R2 change in opposite directions.
  • the first resistor R1 and the second resistor R2 constitute a half-bridge circuit, and the voltage between the first resistor R1 and the second resistor R2 is output as the output voltage V1. The corresponding change in the output voltage V1 can be amplified.
  • the 2nd resistance part R2 should just be equipped with several 2nd strain gauge r2, and the number is not restricted to four.
  • the second strain gauges r2 are preferably arranged at equal intervals on the circumference of the second circle. However, it is possible not to arrange the second strain gauges r2 at equal intervals.
  • each second strain gauge r2 is preferably disposed between the center of the first circle and the second circle and each first strain gauge r1.
  • each second strain gauge r2 is preferably arranged on a line segment connecting the centers of the first circle and the second circle and each first strain gauge r1.
  • the third resistance portion R3 includes four third strain gauges r3 connected in series by printed wiring (not shown).
  • the third strain gauge r3 may be formed by printing a metal material on the insulating layer 2, or may be formed by attaching a metal foil to the insulating layer 2.
  • the third strain gauge r3 may be an independent element mounted on the insulating layer 2. In any case, the entire surface of the third strain gauge r3 is fixed to the strain generating body 1 so as to be distorted according to the strain of the insulating layer 2.
  • the strain generating body 1 when a load is applied to the strain generating body 1, the strain generating body 1 is strained according to the load, the insulating layer 2 is strained together with the strain generating body 1, and the third strain gauge r3 is strained together with the insulating layer 2.
  • the resistance value of each third strain gauge r3 changes according to the strain, and the resistance value of the third resistance portion R3 changes according to the change of the resistance value of each third strain gauge r3.
  • the output voltage V2 changes according to the load.
  • the third strain gauges r3 are arranged at equal intervals (every 90 °) on the circumference of the third circle centered on the center of the strain body 1 (load receiving portion 14). By disposing each third strain gauge r3 in this way, it is possible to suppress an error in the resistance value of the third resistance portion R3 that occurs when the direction of the load is inclined (not vertical) with respect to the strain generating body 1. This is because the strain of the third strain gauge r3 disposed on the side opposite to the tilt direction is reduced at the same time as the strain of the third strain gauge r3 disposed on the load tilt direction side is increased. By suppressing the error of the third resistor R3, the error of the output voltage V2 can be suppressed.
  • the third resistor R3 only needs to include a plurality of third strain gauges r3, and the number is not limited to four. In any case, the third strain gauges r3 are preferably arranged at equal intervals on the circumference of the third circle. However, it is possible not to arrange the third strain gauges r3 at equal intervals.
  • the first strain gauges r1 and the third strain gauges r3 are alternately arranged at equal intervals (every 45 °). Thereby, the difference
  • the first circle and the third circle are preferably the same. That is, it is preferable that the first strain gauge r1 and the third strain gauge r3 are arranged on the same circumference. Thereby, the change of the resistance value of 1st resistance part R1 according to a load and the change of the resistance value of 3rd resistance part R3 can be equalize
  • the fourth resistance portion R4 includes four fourth strain gauges r4 connected in series by printed wiring (not shown).
  • the fourth strain gauge r4 may be formed by printing a metal material on the insulating layer 2, or may be formed by attaching a metal foil to the insulating layer 2.
  • the fourth strain gauge r4 may be an independent element mounted on the insulating layer 2. In any case, the entire surface of the fourth strain gauge r4 is fixed to the strain generating body 1 so as to be distorted according to the strain of the insulating layer 2.
  • the strain generating body 1 when a load is applied to the strain generating body 1, the strain generating body 1 is strained according to the load, the strain generating body 1 and the insulating layer 2 are strained, and the insulating layer 2 and the fourth strain gauge r4 are strained.
  • the resistance value of each fourth strain gauge r4 changes according to the strain, and the resistance value of the fourth resistance portion R4 changes according to the change of the resistance value of each fourth strain gauge r4.
  • the output voltage V2 changes according to the load.
  • the fourth strain gauges r4 are arranged at equal intervals (every 90 °) on the circumference of the fourth circle with the center of the strain body 1 as the center.
  • the fourth circle is a concentric circle of the third circle smaller than the third circle.
  • the outer peripheral portion of the first portion 11 is fixed, when a load is applied to the strain generating body 1, the central portion side and the outer peripheral portion side of the first portion 11 are distorted in opposite directions.
  • the resistance value of the gauge r4 changes in the opposite direction. That is, when a load is applied to the strain generating body 1, the resistance value of the third resistance portion R3 and the resistance value of the fourth resistance portion R4 change in opposite directions.
  • the third resistor portion R3 and the fourth resistor portion R4 constitute a half-bridge circuit, and the voltage between the third resistor portion R3 and the fourth resistor portion R4 is output as the output voltage V2, thereby increasing the load.
  • the corresponding change in the output voltage V2 can be amplified.
  • the 4th resistance part R4 should just be equipped with several 4th strain gauge r4, and the number is not restricted to four. In any case, it is preferable that the fourth strain gauges r4 are arranged at equal intervals on the circumference of the second circle. However, the fourth strain gauges r4 may not be arranged at equal intervals.
  • each fourth strain gauge r4 is preferably arranged between the third circle and the center of the fourth circle and each third strain gauge r3. That is, each fourth strain gauge r4 is preferably arranged on a line segment connecting the third circle and the center of the fourth circle and each third strain gauge r3.
  • the second strain gauges r2 and the fourth strain gauges r4 are alternately arranged at equal intervals (every 45 °). Thereby, the difference
  • the second circle and the fourth circle are preferably the same. That is, it is preferable that the second strain gauge r2 and the fourth strain gauge r4 are arranged on the same circumference. Thereby, the change of the resistance value of 2nd resistance part R2 according to a load and the change of the resistance value of 4th resistance part R4 can be equalize
  • the plurality of first gauge elements r1 are arranged at equal intervals on the circumference of the first circle.
  • the load sensor 100 can accurately detect the load based on the output voltages V1 and V2 even when the direction of the load is inclined with respect to the strain body 1.
  • the influence of the position shift of the first gauge elements r1 is affected by the plurality of first gauge elements r1. Is offset between. The same applies to the second resistor portion R2, the third resistor portion R3, and the fourth resistor portion R4. Therefore, even if the load sensor 100 is misaligned in the first gauge element r1, the second gauge element r2, the third gauge element r3, and the fourth gauge element r4 due to a manufacturing error, the output voltage V1, Based on V2, the load can be detected with high accuracy.
  • the load sensor 100 can accurately detect the load based on the output voltage V1.
  • first portion 11 of the strain body 1 may be oval.
  • first circle, the second circle, the third circle, and the fourth circle are concentric ellipses centered on the center of the first portion 11 (load receiving portion 14), which is similar to the first portion 11. It is preferable.
  • the load detection device according to the present embodiment can be any device including the load sensor 100.
  • the load detection device is, for example, a chair, a bed, a table, or a stretcher, but is not limited thereto.
  • a case where the load detection device is a bed will be described as an example.
  • FIG. 4 is a diagram illustrating an example of the bed 200 according to the present embodiment.
  • the bed 200 in FIG. 4 includes a top plate 4 and four legs 5.
  • the top plate 4 is a part for a person to lie down, and is composed of a frame and a floor plate.
  • the bed 200 is laid with a mattress or the like on the top 4 in use.
  • the leg part 5 supports the top plate 4 horizontally.
  • FIG. 5 is a partially enlarged view showing an example of the leg portion 5 of FIG. 6 is a cross-sectional view of the leg 5 of FIG.
  • the leg portion 5 is disposed between the first support portion 51 that supports the top plate 4, the second support portion 52 that supports the first support portion 51, and the first support portion 51 and the second support portion 52.
  • Load sensor 100 The 1st support part 51 has the recessed part 511 which accommodates the screw 15 of the load sensor 100 in a lower end.
  • the second support part 52 includes a housing 53, a caster 54, and a pressing part 55.
  • the housing 53 is a cylindrical member that connects the first support portion 51 and the casters 54, and has a hollow portion 531.
  • the upper end of the casing 53 is fixed to the lower ends of the load sensor 100 and the first support portion 51, and the lower end of the casing 53 is fixed to the upper end of the casters 54.
  • the load receiving portion 14 of the load sensor 100 is accommodated in the hollow portion 531 of the housing 53.
  • the caster 54 includes a wheel that can rotate about a horizontal axis, and a universal bracket that supports the wheel to rotate about a vertical axis.
  • the bed 200 can be easily moved by the casters 54.
  • the pressing portion 55 is a rod-like member extending upward from the upper end of the caster 54 and is housed in the hollow portion 531 of the housing 53.
  • the pressing portion 55 is designed to have a height at which the upper end of the pressing portion 55 can press the load receiving portion 14 when a load is applied to the bed 200.
  • the load sensor 100 when a person is on the bed 200, the load sensor 100 is pushed down by the first support portion 51, and the load receiving portion 14 is pressed from below by the pressing portion 55. Thereby, since the load according to a person's weight is added to the load receiving part 14, the load sensor 100 can detect a person's weight (load).

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  • General Physics & Mathematics (AREA)
  • Measurement Of Force In General (AREA)

Abstract

A load sensor according to an embodiment is provided with: a strain body provided with a load receiving part; an insulating layer provided on the strain body; a first resistor part and a second resistor part which are provided on the insulating layer and connected in series; and a first output terminal that outputs a voltage between the first resistor part and the second resistor part, wherein: the first resistor part is provided with a plurality of first strain gauges connected in series and arranged on the circumference of a first circle that is a circle or an ellipse; the second resistor part is provided with a plurality of second strain gauges connected in series and arranged on the circumference of a second circle that is a circle or an ellipse; and the first circle and the second circle are concentric circles or concentric ellipses centered on the load receiving part.

Description

荷重センサ及び荷重検出装置Load sensor and load detection device
　本発明は、荷重センサ及び荷重検出装置に関する。 The present invention relates to a load sensor and a load detection device.
　従来、歪ゲージを利用した荷重センサが利用されている。このような荷重センサとして、起歪体上に配置された４つの歪ゲージによりブリッジ回路を形成し、ブリッジ回路の出力電圧により、荷重を検出するものが知られている。 Conventionally, load sensors using strain gauges have been used. As such a load sensor, a sensor in which a bridge circuit is formed by four strain gauges arranged on a strain generating body, and a load is detected by an output voltage of the bridge circuit is known.
特許６０７８４７８号明細書Japanese Patent No. 6078478
　しかしながら、上記従来の荷重センサでは、荷重が加えられる方向が起歪体に対して垂直でない場合、起歪体の歪みに偏りが生じ、荷重の検出精度が低下するという問題があった。 However, the conventional load sensor has a problem that when the direction in which the load is applied is not perpendicular to the strain generating body, the strain of the strain generating body is biased and the load detection accuracy is lowered.
　本発明は、上記の課題に鑑みてなされたものであり、歪ゲージを備えた荷重センサの検出精度を向上させることを目的とする。 The present invention has been made in view of the above-described problems, and an object thereof is to improve the detection accuracy of a load sensor having a strain gauge.
　一実施形態に係る荷重センサは、荷重受け部を備えた起歪体と、前記起歪体上に設けられた絶縁層と、前記絶縁層上に設けられ、直列に接続された第１抵抗部及び第２抵抗部と、前記第１抵抗部と前記第２抵抗部との間の電圧を出力する第１出力端子と、を備え、前記第１抵抗部は、直列に接続され、円又は楕円である第１円の円周上に配置された複数の第１歪ゲージを備え、前記第２抵抗部は、直列に接続され、円又は楕円である第２円の円周上に配置された複数の第２歪ゲージを備え、前記第１円及び前記第２円は、前記荷重受け部を中心とする同心円又は同心楕円である。 A load sensor according to an embodiment includes a strain generating body provided with a load receiving portion, an insulating layer provided on the strain generating body, and a first resistance portion provided on the insulating layer and connected in series. And a first output terminal that outputs a voltage between the first resistance part and the second resistance part, wherein the first resistance part is connected in series and is a circle or an ellipse A plurality of first strain gauges arranged on the circumference of the first circle, and the second resistance portion is connected in series and arranged on the circumference of the second circle that is a circle or an ellipse. A plurality of second strain gauges are provided, and the first circle and the second circle are concentric circles or concentric ellipses around the load receiving portion.
　本発明の各実施形態によれば、歪ゲージを備えた荷重センサの検出精度を向上させることができる。 According to each embodiment of the present invention, the detection accuracy of a load sensor having a strain gauge can be improved.
荷重センサ１００の一例を示す平面図。The top view which shows an example of the load sensor 100. FIG. 荷重センサ１００の一例を示す側面図。The side view which shows an example of the load sensor 100. FIG. 荷重センサ１００の回路構成の一例を示す図。The figure which shows an example of the circuit structure of the load sensor. ベッド２００の一例を示す図。The figure which shows an example of the bed 200. FIG. 図４の脚部５の一例を示す部分拡大図。The elements on larger scale which show an example of the leg part 5 of FIG. 図５の脚部５の断面図。Sectional drawing of the leg part 5 of FIG.
　以下、本発明の各実施形態について、添付の図面を参照しながら説明する。なお、各実施形態に係る明細書及び図面の記載に関して、実質的に同一の機能構成を有する構成要素については、同一の符号を付することにより重畳した説明を省略する。 Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, regarding the description of the specification and the drawings according to each embodiment, constituent elements having substantially the same functional configuration are denoted by the same reference numerals and overlapping description is omitted.
＜第１実施形態＞
　第１実施形態に係る荷重センサ１００について、図１～図３を参照して説明する。本実施形態に係る荷重センサ１００は、加えられた荷重を検出するセンサであり、歪ゲージを備える。歪ゲージとは、その歪みに応じて抵抗値が変化する素子である。図１は、荷重センサ１００の一例を示す平面図である。図２は、荷重センサ１００の一例を示す側面図である。以下、便宜上、図における上下左右を、荷重センサ１００の上下左右として説明する。 <First Embodiment>
A load sensor 100 according to the first embodiment will be described with reference to FIGS. The load sensor 100 according to the present embodiment is a sensor that detects an applied load, and includes a strain gauge. A strain gauge is an element whose resistance value changes according to the strain. FIG. 1 is a plan view showing an example of the load sensor 100. FIG. 2 is a side view showing an example of the load sensor 100. Hereinafter, for convenience, the top, bottom, left, and right in the figure will be described as the top, bottom, left, and right of the load sensor 100.
　図１及び図２に示すように、荷重センサ１００は、起歪体１と、絶縁層２と、第１抵抗部Ｒ１と、第２抵抗部Ｒ２と、第３抵抗部Ｒ３と、第４抵抗部Ｒ４と、第１出力端子Ｔ１と、第１出力端子Ｔ２と、変換回路３と、を備える。 As shown in FIGS. 1 and 2, the load sensor 100 includes a strain body 1, an insulating layer 2, a first resistor R 1, a second resistor R 2, a third resistor R 3, and a fourth resistor. A section R4, a first output terminal T1, a first output terminal T2, and a conversion circuit 3 are provided.
　起歪体１は、荷重を加えられる板状部材であり、金属板により形成される。荷重センサ１００は、歪ゲージを利用して起歪体１の歪みを検出することにより、起歪体１に加えられた荷重を検出する。図１に示すように、起歪体１は、第１部分１１と、第２部分１２と、を有する。 The strain body 1 is a plate-like member to which a load is applied, and is formed of a metal plate. The load sensor 100 detects a load applied to the strain body 1 by detecting strain of the strain body 1 using a strain gauge. As shown in FIG. 1, the strain body 1 includes a first portion 11 and a second portion 12.
　第１部分１１は、荷重に応じて歪む円形の部分である。第１部分１１は、外周部に複数の開口部１３を有し、各開口部１３にボルトを挿通させることにより、外周部を荷重の検出対象に固定される。また、図２に示すように、第１部分１１の中心には、検出対象からの荷重を受ける荷重受け部１４が設けられる。このように、円形の第１部分１１の外周部を固定し、中心に荷重を加えることにより、荷重に応じた第１部分１１の歪みを均一化できる。 The first portion 11 is a circular portion that is distorted according to the load. The first portion 11 has a plurality of openings 13 on the outer peripheral portion, and the outer peripheral portion is fixed to a load detection target by inserting a bolt through each opening 13. As shown in FIG. 2, a load receiver 14 that receives a load from the detection target is provided at the center of the first portion 11. In this way, by fixing the outer peripheral portion of the circular first portion 11 and applying a load at the center, the distortion of the first portion 11 according to the load can be made uniform.
　なお、図２の例では、荷重受け部１４は、頭部が半球状のナットであり、起歪体１の下面に設けられ、起歪体１の上面に設けられたネジ１５を挿通させることによりに第１部分１１に固定されているが、荷重受け部１４の位置及び固定方法はこれに限られない。荷重受け部１４は、起歪体１の上面に設けられてもよいし、ナットにより固定されてもよい。後者の場合、荷重受け部１４として、頭部が半球状のボルトを利用すればよい。 In the example of FIG. 2, the load receiving portion 14 is a nut having a hemispherical head, is provided on the lower surface of the strain body 1, and is inserted with a screw 15 provided on the upper surface of the strain body 1. However, the position and fixing method of the load receiving portion 14 are not limited to this. The load receiver 14 may be provided on the upper surface of the strain body 1 or may be fixed by a nut. In the latter case, a bolt having a hemispherical head may be used as the load receiving portion 14.
　第２部分１２は、第１部分１１から延出した略矩形の部分である。第２部分１２の形状は任意に設計可能である。 The second portion 12 is a substantially rectangular portion extending from the first portion 11. The shape of the second portion 12 can be arbitrarily designed.
　絶縁層２は、起歪体１上に設けられた絶縁性の層である。絶縁層２は、起歪体１上に形成された酸化膜、窒化膜、又は樹脂製の絶縁膜であってもよいし、起歪体１上に固定された絶縁性のプリント基板であってもよい。プリント基板は、フレキシブル基板であってもよいし、リジッド基板であってもよい。いずれの場合も、絶縁層２は、起歪体１の歪みに応じて歪むように、全面を起歪体１に固定される。絶縁層２は、第１部分２１と、第２部分２２と、を有する。 The insulating layer 2 is an insulating layer provided on the strain body 1. The insulating layer 2 may be an oxide film, a nitride film, or a resin insulating film formed on the strain generating body 1, or an insulating printed board fixed on the strain generating body 1. Also good. The printed circuit board may be a flexible board or a rigid board. In any case, the entire surface of the insulating layer 2 is fixed to the strain generating body 1 so as to be distorted according to the strain of the strain generating body 1. The insulating layer 2 has a first portion 21 and a second portion 22.
　第１部分２１は、荷重に応じて歪む円形の部分である。第１部分２１は、起歪体１の第１部分１１に、第１部分１１と中心が一致するように固定される。第１部分１１には、第１抵抗部Ｒ１、第２抵抗部Ｒ２、第３抵抗部Ｒ３、及び第４抵抗部Ｒ４が設けられる。また、第１部分２１の中心部には、ネジ１５を挿通させるための開口部が設けられる。 The first portion 21 is a circular portion that is distorted according to the load. The first portion 21 is fixed to the first portion 11 of the strain body 1 so that the center thereof coincides with the first portion 11. The first portion 11 is provided with a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4. In addition, an opening for inserting the screw 15 is provided at the center of the first portion 21.
　第２部分２２は、第１部分２１から延出した略矩形の部分である。第２部分２２の形状は任意に設計可能である。第２部分２２は、起歪体１の第１部分１１から第２部分１２に亘って設けられる。起歪体１の第２部分１２上の第２部分２２には、変換回路３が設けられる。 The second portion 22 is a substantially rectangular portion extending from the first portion 21. The shape of the second portion 22 can be arbitrarily designed. The second portion 22 is provided from the first portion 11 to the second portion 12 of the strain body 1. The conversion circuit 3 is provided in the second portion 22 on the second portion 12 of the strain generating body 1.
　ここで、絶縁層２上に形成される回路構成について、図３を参照して説明する。図３は、荷重センサ１００の回路構成の一例を示す図である。図３に示すように、絶縁層２上には、第１抵抗部Ｒ１と、第２抵抗部Ｒ２と、第３抵抗部Ｒ３と、第４抵抗部Ｒ４と、第１出力端子Ｔ１と、第２出力端子Ｔ２と、変換回路３と、が設けられる。 Here, a circuit configuration formed on the insulating layer 2 will be described with reference to FIG. FIG. 3 is a diagram illustrating an example of a circuit configuration of the load sensor 100. As shown in FIG. 3, on the insulating layer 2, the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the first output terminal T1, and the first resistor A two-output terminal T2 and a conversion circuit 3 are provided.
　第１抵抗部Ｒ１は、一端が電源に接続され、他端が第１出力端子Ｔ１に接続される。第２抵抗部Ｒ１は、一端が第１出力端子Ｔ１に接続され、他端がグラウンドに接続される。すなわち、第１抵抗部Ｒ１及び第２抵抗部Ｒ２は、直列に接続され、ハーフブリッジ回路を構成する。第１抵抗部Ｒ１と第２抵抗部Ｒ２との間の電圧（電源電圧Ｖｄｄを第１抵抗部Ｒ１及び第２抵抗部Ｒ２で分圧した電圧）が、第１出力端子Ｔ１から出力電圧Ｖ１として出力される。第１出力端子Ｔ１は、変換回路３に接続され、出力電圧Ｖ１は、変換回路３に入力される。 The first resistor R1 has one end connected to the power supply and the other end connected to the first output terminal T1. The second resistor unit R1 has one end connected to the first output terminal T1 and the other end connected to the ground. That is, the first resistor R1 and the second resistor R2 are connected in series to form a half bridge circuit. A voltage between the first resistor R1 and the second resistor R2 (a voltage obtained by dividing the power supply voltage Vdd by the first resistor R1 and the second resistor R2) is output from the first output terminal T1 as the output voltage V1. Is output. The first output terminal T <b> 1 is connected to the conversion circuit 3, and the output voltage V <b> 1 is input to the conversion circuit 3.
　第３抵抗部Ｒ３は、一端が電源に接続され、他端が第２出力端子Ｔ２に接続される。第４抵抗部Ｒ４は、一端が第２出力端子Ｔ２に接続され、他端がグラウンドに接続される。すなわち、第３抵抗部Ｒ３及び第４抵抗部Ｒ４は、直列に接続され、ハーフブリッジ回路を構成する。第３抵抗部Ｒ３と第４抵抗部Ｒ４との間の電圧（電源電圧Ｖｄｄを第３抵抗部Ｒ３及び第４抵抗部Ｒ４で分圧した電圧）が、第２出力端子Ｔ２から出力電圧Ｖ２として出力される。第２出力端子Ｔ２は、変換回路３に接続され、出力電圧Ｖ２は、変換回路３に入力される。 The third resistor R3 has one end connected to the power supply and the other end connected to the second output terminal T2. The fourth resistor unit R4 has one end connected to the second output terminal T2 and the other end connected to the ground. That is, the third resistor unit R3 and the fourth resistor unit R4 are connected in series to form a half bridge circuit. A voltage between the third resistor R3 and the fourth resistor R4 (a voltage obtained by dividing the power supply voltage Vdd by the third resistor R3 and the fourth resistor R4) is output from the second output terminal T2 as an output voltage V2. Is output. The second output terminal T2 is connected to the conversion circuit 3, and the output voltage V2 is input to the conversion circuit 3.
　図３からわかるように、第３抵抗部Ｒ３及び第４抵抗部Ｒ４は、第１抵抗部Ｒ１及び第２抵抗部Ｒ２と並列に接続され、第１抵抗部Ｒ１及び第２抵抗部Ｒ２と共にブリッジ回路を構成する。第１抵抗部Ｒ１、第２抵抗部Ｒ２、第３抵抗部Ｒ３、及び第４抵抗部Ｒ４は、後述する通り、いずれも複数の歪ゲージを備え、荷重に応じて抵抗値が変化する。このため、出力電圧Ｖ１は、荷重に応じて変化した第１抵抗部Ｒ１及び第２抵抗部Ｒ２の抵抗値に応じた電圧となる。同様に、出力電圧Ｖ２は、荷重に応じて変化した第３抵抗部Ｒ３及び第４抵抗部Ｒ４の抵抗値に応じた電圧となる。すなわち、出力電圧Ｖ１，Ｖ２は、いずれも荷重に応じた電圧となる。 As can be seen from FIG. 3, the third resistor R3 and the fourth resistor R4 are connected in parallel with the first resistor R1 and the second resistor R2, and are bridged together with the first resistor R1 and the second resistor R2. Configure the circuit. As will be described later, each of the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 includes a plurality of strain gauges, and the resistance value changes according to the load. For this reason, the output voltage V1 becomes a voltage according to the resistance values of the first resistance part R1 and the second resistance part R2 that have changed according to the load. Similarly, the output voltage V2 becomes a voltage according to the resistance values of the third resistor portion R3 and the fourth resistor portion R4 that have changed according to the load. That is, the output voltages V1, V2 are both voltages according to the load.
　変換回路３は、出力電圧Ｖ１，Ｖ２に基づいて、荷重を検出する回路である。具体的には、変換回路３は、出力電圧Ｖ１，Ｖ２の差を、予め用意されたテーブルを参照して、荷重に変換する。図３の例では、変換回路３が１つのＩＣ（Integrated Circuit）である場合を想定しているが、変換回路３は、複数のディスクリート部品により構成されてもよい。 The conversion circuit 3 is a circuit that detects a load based on the output voltages V1 and V2. Specifically, the conversion circuit 3 converts the difference between the output voltages V1 and V2 into a load with reference to a table prepared in advance. In the example of FIG. 3, it is assumed that the conversion circuit 3 is one IC (Integrated Circuit), but the conversion circuit 3 may be configured by a plurality of discrete components.
　次に、第１抵抗部Ｒ１、第２抵抗部Ｒ２、第３抵抗部Ｒ３、及び第４抵抗部Ｒ４の構成について、図１を参照して説明する。 Next, the configuration of the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 will be described with reference to FIG.
　第１抵抗部Ｒ１は、プリント配線（図示省略）により直列に接続された４つの第１歪ゲージｒ１を備える。第１歪ゲージｒ１は、絶縁層２に金属材料やカーボンをバインダー樹脂に混ぜ込んだ抵抗材料をプリントすることにより形成されてもよいし、絶縁層２に金属箔を貼付することにより形成されてもよい。また、第１歪ゲージｒ１は、絶縁層２に実装された独立した素子であってもよい。いずれの場合も、第１歪ゲージｒ１は、絶縁層２の歪みに応じて歪むように、全面を起歪体１に固定される。このような構成により、起歪体１に荷重が加わると、荷重に応じて起歪体１が歪み、起歪体１と共に絶縁層２が歪み、絶縁層２と共に第１歪ゲージｒ１が歪み、歪みに応じて各第１歪ゲージｒ１の抵抗値が変化し、各第１歪ゲージｒ１の抵抗値の変化に応じて第１抵抗部Ｒ１の抵抗値が変化する。結果として、出力電圧Ｖ１が、荷重に応じて変化する。 The first resistance portion R1 includes four first strain gauges r1 connected in series by printed wiring (not shown). The first strain gauge r1 may be formed by printing a resistance material in which a metal material or carbon is mixed with a binder resin on the insulating layer 2, or formed by sticking a metal foil to the insulating layer 2. Also good. The first strain gauge r1 may be an independent element mounted on the insulating layer 2. In any case, the entire surface of the first strain gauge r1 is fixed to the strain generating body 1 so as to be distorted according to the strain of the insulating layer 2. With such a configuration, when a load is applied to the strain body 1, the strain body 1 is distorted according to the load, the insulation layer 2 is distorted together with the strain body 1, and the first strain gauge r1 is strained together with the insulation layer 2. The resistance value of each first strain gauge r1 changes according to the strain, and the resistance value of the first resistance unit R1 changes according to the change of the resistance value of each first strain gauge r1. As a result, the output voltage V1 changes according to the load.
　各第１歪ゲージｒ１は、起歪体１の中心（荷重受け部１４）を中心とした第１円の円周上に、等間隔（９０°ごと）に配置される。各第１歪ゲージｒ１をこのように配置することにより、荷重の方向が起歪体１に対して傾いている（垂直でない）場合に生じる第１抵抗部Ｒ１の抵抗値の誤差を抑制できる。これは、荷重の傾斜方向側に配置された第１歪ゲージｒ１の歪みが大きくなると同時に、傾斜方向と反対側に配置された第１歪ゲージｒ１の歪が小さくなるためである。第１抵抗部Ｒ１の誤差を抑制することにより、出力電圧Ｖ１の誤差を抑制できる。 The first strain gauges r1 are arranged at equal intervals (every 90 °) on the circumference of the first circle centered on the center of the strain body 1 (load receiving portion 14). By disposing each first strain gauge r1 in this way, it is possible to suppress an error in the resistance value of the first resistance portion R1 that occurs when the direction of the load is inclined (not perpendicular) to the strain generating body 1. This is because the strain of the first strain gauge r1 disposed on the side opposite to the tilt direction is decreased at the same time as the strain of the first strain gauge r1 disposed on the tilt direction side of the load is increased. By suppressing the error of the first resistance unit R1, the error of the output voltage V1 can be suppressed.
　なお、第１抵抗部Ｒ１は、複数の第１歪ゲージｒ１を備えればよく、その数は４つに限られない。いずれの場合も、各第１歪ゲージｒ１は、第１円の円周上に等間隔に配置されるのが好ましい。ただし、各第１歪ゲージｒ１を等間隔に配置しないことも可能である。 In addition, the 1st resistance part R1 should just be provided with the some 1st strain gauge r1, and the number is not restricted to four. In any case, the first strain gauges r1 are preferably arranged at equal intervals on the circumference of the first circle. However, it is possible not to arrange the first strain gauges r1 at equal intervals.
　第２抵抗部Ｒ２は、プリント配線（図示省略）により直列に接続された４つの第２歪ゲージｒ２を備える。第２歪ゲージｒ２は、絶縁層２に金属材料をプリントすることにより形成されてもよいし、絶縁層２に金属箔を貼付することにより形成されてもよい。また、第２歪ゲージｒ２は、絶縁層２に実装された独立した素子であってもよい。いずれの場合も、第２歪ゲージｒ２は、絶縁層２の歪みに応じて歪むように、全面を起歪体１に固定される。このような構成により、起歪体１に荷重が加わると、荷重に応じて起歪体１が歪み、起歪体１と共に絶縁層２が歪み、絶縁層２と共に第２歪ゲージｒ２が歪み、歪みに応じて各第２歪ゲージｒ２の抵抗値が変化し、各第２歪ゲージｒ２の抵抗値の変化に応じて第２抵抗部Ｒ２の抵抗値が変化する。結果として、出力電圧Ｖ１が、荷重に応じて変化する。 The second resistance portion R2 includes four second strain gauges r2 connected in series by printed wiring (not shown). The second strain gauge r <b> 2 may be formed by printing a metal material on the insulating layer 2, or may be formed by attaching a metal foil to the insulating layer 2. The second strain gauge r2 may be an independent element mounted on the insulating layer 2. In either case, the entire surface of the second strain gauge r2 is fixed to the strain generating body 1 so as to be distorted in accordance with the strain of the insulating layer 2. With such a configuration, when a load is applied to the strain generating body 1, the strain generating body 1 is strained according to the load, the strain generating body 1 and the insulating layer 2 are strained, and the insulating layer 2 and the second strain gauge r2 are strained. The resistance value of each second strain gauge r2 changes according to the strain, and the resistance value of the second resistance portion R2 changes according to the change of the resistance value of each second strain gauge r2. As a result, the output voltage V1 changes according to the load.
　各第２歪ゲージｒ２は、起歪体１の中心を中心とした第２円の円周上に、等間隔（９０°ごと）に配置される。第２円は、第１円より小さい第１円の同心円である。各第２歪ゲージｒ２をこのように配置することにより、荷重の方向が起歪体１に対して傾いている場合に生じる第２抵抗部Ｒ２の抵抗値の誤差を抑制できる。これは、荷重の傾斜方向側に配置された第２歪ゲージｒ２の歪みが大きくなると同時に、傾斜方向と反対側に配置された第２歪ゲージｒ２の歪が小さくなるためである。第２抵抗部Ｒ２の誤差を抑制することにより、出力電圧Ｖ２の誤差を抑制できる。 The second strain gauges r2 are arranged at equal intervals (every 90 °) on the circumference of the second circle with the center of the strain generating body 1 as the center. The second circle is a concentric circle of the first circle smaller than the first circle. By disposing each second strain gauge r2 in this way, it is possible to suppress an error in the resistance value of the second resistance portion R2 that occurs when the direction of the load is inclined with respect to the strain generating body 1. This is because the strain of the second strain gauge r2 disposed on the side opposite to the tilt direction is reduced at the same time as the strain of the second strain gauge r2 disposed on the load tilt direction side is increased. By suppressing the error of the second resistance unit R2, the error of the output voltage V2 can be suppressed.
　また、第１部分１１の外周部は固定されているため、起歪体１に荷重が加わると、第１部分１１の中心部側と外周部側とは逆向きに歪む。この結果、起歪体１に荷重が加わると、第１部分１１の外周部側に配置された第１歪ゲージｒ１の抵抗値と、第１部分１１の中心部側に配置された第２歪ゲージｒ２の抵抗値と、は逆向きに変化する。すなわち、起歪体１に荷重が加わると、第１抵抗部Ｒ１の抵抗値と、第２抵抗部Ｒ２の抵抗値と、は逆向きに変化する。このような第１抵抗部Ｒ１及び第２抵抗部Ｒ２によりハーフブリッジ回路を構成し、第１抵抗部Ｒ１と第２抵抗部Ｒ２との間の電圧を出力電圧Ｖ１として出力することにより、荷重に応じた出力電圧Ｖ１の変化を増幅することができる。 Further, since the outer peripheral portion of the first portion 11 is fixed, when a load is applied to the strain generating body 1, the central portion side and the outer peripheral portion side of the first portion 11 are distorted in opposite directions. As a result, when a load is applied to the strain generating body 1, the resistance value of the first strain gauge r <b> 1 disposed on the outer peripheral side of the first portion 11 and the second strain disposed on the central portion side of the first portion 11. The resistance value of the gauge r2 changes in the opposite direction. That is, when a load is applied to the strain body 1, the resistance value of the first resistance part R1 and the resistance value of the second resistance part R2 change in opposite directions. The first resistor R1 and the second resistor R2 constitute a half-bridge circuit, and the voltage between the first resistor R1 and the second resistor R2 is output as the output voltage V1. The corresponding change in the output voltage V1 can be amplified.
　なお、第２抵抗部Ｒ２は、複数の第２歪ゲージｒ２を備えればよく、その数は４つに限られない。いずれの場合も、各第２歪ゲージｒ２は、第２円の円周上に等間隔に配置されるのが好ましい。ただし、各第２歪ゲージｒ２を等間隔に配置しないことも可能である。 In addition, the 2nd resistance part R2 should just be equipped with several 2nd strain gauge r2, and the number is not restricted to four. In any case, the second strain gauges r2 are preferably arranged at equal intervals on the circumference of the second circle. However, it is possible not to arrange the second strain gauges r2 at equal intervals.
　また、図１の例のように、各第２歪ゲージｒ２は、第１円及び第２円の中心と、各第１歪ゲージｒ１と、の間に配置されるのが好ましい。すなわち、各第２歪ゲージｒ２は、第１円及び第２円の中心と、各第１歪ゲージｒ１と、を結ぶ線分上に配置されるのが好ましい。第１歪ゲージｒ１及び第２歪ゲージｒ２をこのように配置することにより、荷重の方向の傾斜による影響を、第１抵抗部Ｒ１及び第２抵抗部Ｒ２の間で均一化できる。 Also, as in the example of FIG. 1, each second strain gauge r2 is preferably disposed between the center of the first circle and the second circle and each first strain gauge r1. In other words, each second strain gauge r2 is preferably arranged on a line segment connecting the centers of the first circle and the second circle and each first strain gauge r1. By arranging the first strain gauge r1 and the second strain gauge r2 in this way, the influence of the inclination in the direction of the load can be made uniform between the first resistance portion R1 and the second resistance portion R2.
　第３抵抗部Ｒ３は、プリント配線（図示省略）により直列に接続された４つの第３歪ゲージｒ３を備える。第３歪ゲージｒ３は、絶縁層２に金属材料をプリントすることにより形成されてもよいし、絶縁層２に金属箔を貼付することにより形成されてもよい。また、第３歪ゲージｒ３は、絶縁層２に実装された独立した素子であってもよい。いずれの場合も、第３歪ゲージｒ３は、絶縁層２の歪みに応じて歪むように、全面を起歪体１に固定される。このような構成により、起歪体１に荷重が加わると、荷重に応じて起歪体１が歪み、起歪体１と共に絶縁層２が歪み、絶縁層２と共に第３歪ゲージｒ３が歪み、歪みに応じて各第３歪ゲージｒ３の抵抗値が変化し、各第３歪ゲージｒ３の抵抗値の変化に応じて第３抵抗部Ｒ３の抵抗値が変化する。結果として、出力電圧Ｖ２が、荷重に応じて変化する。 The third resistance portion R3 includes four third strain gauges r3 connected in series by printed wiring (not shown). The third strain gauge r3 may be formed by printing a metal material on the insulating layer 2, or may be formed by attaching a metal foil to the insulating layer 2. The third strain gauge r3 may be an independent element mounted on the insulating layer 2. In any case, the entire surface of the third strain gauge r3 is fixed to the strain generating body 1 so as to be distorted according to the strain of the insulating layer 2. With such a configuration, when a load is applied to the strain generating body 1, the strain generating body 1 is strained according to the load, the insulating layer 2 is strained together with the strain generating body 1, and the third strain gauge r3 is strained together with the insulating layer 2. The resistance value of each third strain gauge r3 changes according to the strain, and the resistance value of the third resistance portion R3 changes according to the change of the resistance value of each third strain gauge r3. As a result, the output voltage V2 changes according to the load.
　各第３歪ゲージｒ３は、起歪体１の中心（荷重受け部１４）を中心とした第３円の円周上に、等間隔（９０°ごと）に配置される。各第３歪ゲージｒ３をこのように配置することにより、荷重の方向が起歪体１に対して傾いている（垂直でない）場合に生じる第３抵抗部Ｒ３の抵抗値の誤差を抑制できる。これは、荷重の傾斜方向側に配置された第３歪ゲージｒ３の歪みが大きくなると同時に、傾斜方向と反対側に配置された第３歪ゲージｒ３の歪が小さくなるためである。第３抵抗部Ｒ３の誤差を抑制することにより、出力電圧Ｖ２の誤差を抑制できる。 The third strain gauges r3 are arranged at equal intervals (every 90 °) on the circumference of the third circle centered on the center of the strain body 1 (load receiving portion 14). By disposing each third strain gauge r3 in this way, it is possible to suppress an error in the resistance value of the third resistance portion R3 that occurs when the direction of the load is inclined (not vertical) with respect to the strain generating body 1. This is because the strain of the third strain gauge r3 disposed on the side opposite to the tilt direction is reduced at the same time as the strain of the third strain gauge r3 disposed on the load tilt direction side is increased. By suppressing the error of the third resistor R3, the error of the output voltage V2 can be suppressed.
　なお、第３抵抗部Ｒ３は、複数の第３歪ゲージｒ３を備えればよく、その数は４つに限られない。いずれの場合も、各第３歪ゲージｒ３は、第３円の円周上に等間隔に配置されるのが好ましい。ただし、各第３歪ゲージｒ３を等間隔に配置しないことも可能である。 Note that the third resistor R3 only needs to include a plurality of third strain gauges r3, and the number is not limited to four. In any case, the third strain gauges r3 are preferably arranged at equal intervals on the circumference of the third circle. However, it is possible not to arrange the third strain gauges r3 at equal intervals.
　また、各第１歪ゲージｒ１と各第３歪ゲージｒ３とは、交互に等間隔（４５°ごと）に配置されるのが好ましい。これにより、荷重の方向が起歪体１に対して傾いている場合に生じる出力電圧Ｖ１，Ｖ２の差の誤差を抑制できる。 Further, it is preferable that the first strain gauges r1 and the third strain gauges r3 are alternately arranged at equal intervals (every 45 °). Thereby, the difference | error of the difference of output voltage V1, V2 produced when the direction of a load inclines with respect to the strain body 1 can be suppressed.
　また、第１円及び第３円は同一であるのが好ましい。すなわち、第１歪ゲージｒ１と第３歪ゲージｒ３とは同一円周上に配置されるのが好ましい。これにより、荷重に応じた第１抵抗部Ｒ１の抵抗値の変化と第３抵抗部Ｒ３の抵抗値の変化とを均一化できる。 Also, the first circle and the third circle are preferably the same. That is, it is preferable that the first strain gauge r1 and the third strain gauge r3 are arranged on the same circumference. Thereby, the change of the resistance value of 1st resistance part R1 according to a load and the change of the resistance value of 3rd resistance part R3 can be equalize | homogenized.
　第４抵抗部Ｒ４は、プリント配線（図示省略）により直列に接続された４つの第４歪ゲージｒ４を備える。第４歪ゲージｒ４は、絶縁層２に金属材料をプリントすることにより形成されてもよいし、絶縁層２に金属箔を貼付することにより形成されてもよい。また、第４歪ゲージｒ４は、絶縁層２に実装された独立した素子であってもよい。いずれの場合も、第４歪ゲージｒ４は、絶縁層２の歪みに応じて歪むように、全面を起歪体１に固定される。このような構成により、起歪体１に荷重が加わると、荷重に応じて起歪体１が歪み、起歪体１と共に絶縁層２が歪み、絶縁層２と共に第４歪ゲージｒ４が歪み、歪みに応じて各第４歪ゲージｒ４の抵抗値が変化し、各第４歪ゲージｒ４の抵抗値の変化に応じて第４抵抗部Ｒ４の抵抗値が変化する。結果として、出力電圧Ｖ２が、荷重に応じて変化する。 The fourth resistance portion R4 includes four fourth strain gauges r4 connected in series by printed wiring (not shown). The fourth strain gauge r4 may be formed by printing a metal material on the insulating layer 2, or may be formed by attaching a metal foil to the insulating layer 2. The fourth strain gauge r4 may be an independent element mounted on the insulating layer 2. In any case, the entire surface of the fourth strain gauge r4 is fixed to the strain generating body 1 so as to be distorted according to the strain of the insulating layer 2. With such a configuration, when a load is applied to the strain generating body 1, the strain generating body 1 is strained according to the load, the strain generating body 1 and the insulating layer 2 are strained, and the insulating layer 2 and the fourth strain gauge r4 are strained. The resistance value of each fourth strain gauge r4 changes according to the strain, and the resistance value of the fourth resistance portion R4 changes according to the change of the resistance value of each fourth strain gauge r4. As a result, the output voltage V2 changes according to the load.
　各第４歪ゲージｒ４は、起歪体１の中心を中心とした第４円の円周上に、等間隔（９０°ごと）に配置される。第４円は、第３円より小さい第３円の同心円である。各第４歪ゲージｒ４をこのように配置することにより、荷重の方向が起歪体１に対して傾いている場合に生じる第４抵抗部Ｒ４の抵抗値の誤差を抑制できる。これは、荷重の傾斜方向側に配置された第４歪ゲージｒ４の歪みが大きくなると同時に、傾斜方向と反対側に配置された第４歪ゲージｒ４の歪が小さくなるためである。第４抵抗部Ｒ４の誤差を抑制することにより、出力電圧Ｖ２の誤差を抑制できる。 The fourth strain gauges r4 are arranged at equal intervals (every 90 °) on the circumference of the fourth circle with the center of the strain body 1 as the center. The fourth circle is a concentric circle of the third circle smaller than the third circle. By disposing each fourth strain gauge r4 in this way, it is possible to suppress an error in the resistance value of the fourth resistance portion R4 that occurs when the direction of the load is inclined with respect to the strain generating body 1. This is because the strain of the fourth strain gauge r4 disposed on the side opposite to the tilt direction is reduced at the same time as the strain of the fourth strain gauge r4 disposed on the load tilt direction side is increased. By suppressing the error of the fourth resistor R4, the error of the output voltage V2 can be suppressed.
　また、第１部分１１の外周部は固定されているため、起歪体１に荷重が加わると、第１部分１１の中心部側と外周部側とは逆向きに歪む。この結果、起歪体１に荷重が加わると、第１部分１１の外周部側に配置された第３歪ゲージｒ３の抵抗値と、第１部分１１の中心部側に配置された第４歪ゲージｒ４の抵抗値と、は逆向きに変化する。すなわち、起歪体１に荷重が加わると、第３抵抗部Ｒ３の抵抗値と、第４抵抗部Ｒ４の抵抗値と、は逆向きに変化する。このような第３抵抗部Ｒ３及び第４抵抗部Ｒ４によりハーフブリッジ回路を構成し、第３抵抗部Ｒ３と第４抵抗部Ｒ４との間の電圧を出力電圧Ｖ２として出力することにより、荷重に応じた出力電圧Ｖ２の変化を増幅することができる。 Further, since the outer peripheral portion of the first portion 11 is fixed, when a load is applied to the strain generating body 1, the central portion side and the outer peripheral portion side of the first portion 11 are distorted in opposite directions. As a result, when a load is applied to the strain generating body 1, the resistance value of the third strain gauge r <b> 3 disposed on the outer peripheral side of the first portion 11 and the fourth strain disposed on the center portion side of the first portion 11. The resistance value of the gauge r4 changes in the opposite direction. That is, when a load is applied to the strain generating body 1, the resistance value of the third resistance portion R3 and the resistance value of the fourth resistance portion R4 change in opposite directions. The third resistor portion R3 and the fourth resistor portion R4 constitute a half-bridge circuit, and the voltage between the third resistor portion R3 and the fourth resistor portion R4 is output as the output voltage V2, thereby increasing the load. The corresponding change in the output voltage V2 can be amplified.
　なお、第４抵抗部Ｒ４は、複数の第４歪ゲージｒ４を備えればよく、その数は４つに限られない。いずれの場合も、各第４歪ゲージｒ４は、第２円の円周上に等間隔に配置されるのが好ましい。ただし、各第４歪ゲージｒ４を等間隔に配置しないことも可能である。 In addition, the 4th resistance part R4 should just be equipped with several 4th strain gauge r4, and the number is not restricted to four. In any case, it is preferable that the fourth strain gauges r4 are arranged at equal intervals on the circumference of the second circle. However, the fourth strain gauges r4 may not be arranged at equal intervals.
　また、図１の例のように、各第４歪ゲージｒ４は、第３円及び第４円の中心と、各第３歪ゲージｒ３と、の間に配置されるのが好ましい。すなわち、各第４歪ゲージｒ４は、第３円及び第４円の中心と、各第３歪ゲージｒ３と、を結ぶ線分上に配置されるのが好ましい。第３歪ゲージｒ３及び第４歪ゲージｒ４をこのように配置することにより、荷重の方向の傾斜による影響を、第３抵抗部Ｒ３及び第４抵抗部Ｒ４の間で均一化できる。 Further, as in the example of FIG. 1, each fourth strain gauge r4 is preferably arranged between the third circle and the center of the fourth circle and each third strain gauge r3. That is, each fourth strain gauge r4 is preferably arranged on a line segment connecting the third circle and the center of the fourth circle and each third strain gauge r3. By arranging the third strain gauge r3 and the fourth strain gauge r4 in this way, the influence of the inclination in the direction of the load can be made uniform between the third resistance portion R3 and the fourth resistance portion R4.
　また、各第２歪ゲージｒ２と各第４歪ゲージｒ４とは、交互に等間隔（４５°ごと）に配置されるのが好ましい。これにより、荷重の方向が起歪体１に対して傾いている場合に生じる出力電圧Ｖ１，Ｖ２の差の誤差を抑制できる。 Also, it is preferable that the second strain gauges r2 and the fourth strain gauges r4 are alternately arranged at equal intervals (every 45 °). Thereby, the difference | error of the difference of output voltage V1, V2 produced when the direction of a load inclines with respect to the strain body 1 can be suppressed.
　また、第２円及び第４円は同一であるのが好ましい。すなわち、第２歪ゲージｒ２と第４歪ゲージｒ４とは同一円周上に配置されるのが好ましい。これにより、荷重に応じた第２抵抗部Ｒ２の抵抗値の変化と第４抵抗部Ｒ４の抵抗値の変化とを均一化できる。 Also, the second circle and the fourth circle are preferably the same. That is, it is preferable that the second strain gauge r2 and the fourth strain gauge r4 are arranged on the same circumference. Thereby, the change of the resistance value of 2nd resistance part R2 according to a load and the change of the resistance value of 4th resistance part R4 can be equalize | homogenized.
　以上説明した通り、本実施形態によれば、複数の第１ゲージ素子ｒ１は第１円の円周上に等間隔に配置される。このような構成により、荷重の方向が起歪体１に対して傾いている場合であっても、荷重の傾斜による影響が、複数の第１ゲージ素子ｒ１の間で相殺される。これは、第２抵抗部Ｒ２、第３抵抗部Ｒ３、及び第４抵抗部Ｒ４についても同様である。したがって、荷重センサ１００は、荷重の方向が起歪体１に対して傾いている場合であっても、出力電圧Ｖ１，Ｖ２に基づいて、精度よく荷重を検出することができる。 As described above, according to the present embodiment, the plurality of first gauge elements r1 are arranged at equal intervals on the circumference of the first circle. With such a configuration, even when the direction of the load is inclined with respect to the strain body 1, the influence due to the inclination of the load is canceled between the plurality of first gauge elements r <b> 1. The same applies to the second resistor portion R2, the third resistor portion R3, and the fourth resistor portion R4. Therefore, the load sensor 100 can accurately detect the load based on the output voltages V1 and V2 even when the direction of the load is inclined with respect to the strain body 1.
　また、本実施形態によれば、製造誤差により、複数の第１ゲージ素子ｒ１の位置がずれた場合であっても、第１ゲージ素子ｒ１の位置ずれによる影響が、複数の第１ゲージ素子ｒ１の間で相殺される。これは、第２抵抗部Ｒ２、第３抵抗部Ｒ３、及び第４抵抗部Ｒ４についても同様である。したがって、荷重センサ１００は、製造誤差により第１ゲージ素子ｒ１、第２ゲージ素子ｒ２、第３ゲージ素子ｒ３、及び第４ゲージ素子ｒ４に位置ずれが生じた場合であっても、出力電圧Ｖ１，Ｖ２に基づいて、精度よく荷重を検出することができる。 Further, according to the present embodiment, even if the positions of the plurality of first gauge elements r1 are shifted due to manufacturing errors, the influence of the position shift of the first gauge elements r1 is affected by the plurality of first gauge elements r1. Is offset between. The same applies to the second resistor portion R2, the third resistor portion R3, and the fourth resistor portion R4. Therefore, even if the load sensor 100 is misaligned in the first gauge element r1, the second gauge element r2, the third gauge element r3, and the fourth gauge element r4 due to a manufacturing error, the output voltage V1, Based on V2, the load can be detected with high accuracy.
　なお、本実施形態において、第３抵抗部Ｒ３及び第４抵抗部Ｒ４を備えない構成も可能である。このような場合であっても、荷重センサ１００は、出力電圧Ｖ１に基づいて、精度よく荷重を検出することができる。 In addition, in this embodiment, the structure which is not provided with 3rd resistance part R3 and 4th resistance part R4 is also possible. Even in such a case, the load sensor 100 can accurately detect the load based on the output voltage V1.
　また、起歪体１の第１部分１１は、楕円形であってもよい。この場合、第１円、第２円、第３円、及び第４円は、第１部分１１と相似形の、第１部分１１の中心（荷重受け部１４）を中心とした同心楕円であることが好ましい。 Further, the first portion 11 of the strain body 1 may be oval. In this case, the first circle, the second circle, the third circle, and the fourth circle are concentric ellipses centered on the center of the first portion 11 (load receiving portion 14), which is similar to the first portion 11. It is preferable.
＜第２実施形態＞
　第２実施形態に係る荷重検出装置について、図４～図６を参照して説明する。本実施形態に係る荷重検出装置は、荷重センサ１００を備えた任意の装置で有り得る。荷重検出装置は、例えば、椅子、ベッド、テーブル、又は担架であるが、これに限られない。以下、荷重検出装置がベッドである場合を例に説明する。 Second Embodiment
A load detection apparatus according to the second embodiment will be described with reference to FIGS. The load detection device according to the present embodiment can be any device including the load sensor 100. The load detection device is, for example, a chair, a bed, a table, or a stretcher, but is not limited thereto. Hereinafter, a case where the load detection device is a bed will be described as an example.
　図４は、本実施形態に係るベッド２００の一例を示す図である。図４のベッド２００は、天板４と、４つの脚部５と、を備える。天板４は、人が横たわるための部分であり、フレームや床板により構成される。ベッド２００は、使用時において、天板４の上部にマットレスなどを敷かれる。脚部５は、天板４を水平に支持する。 FIG. 4 is a diagram illustrating an example of the bed 200 according to the present embodiment. The bed 200 in FIG. 4 includes a top plate 4 and four legs 5. The top plate 4 is a part for a person to lie down, and is composed of a frame and a floor plate. The bed 200 is laid with a mattress or the like on the top 4 in use. The leg part 5 supports the top plate 4 horizontally.
　図５は、図４の脚部５の一例を示す部分拡大図である。図６は、図５の脚部５の断面図である。脚部５は、天板４を支持する第１支持部５１と、第１支持部５１を支持する第２支持部５２と、第１支持部５１と第２支持部５２との間に配置された荷重センサ１００と、を備える。第１支持部５１は、下端に荷重センサ１００のネジ１５を収納する凹部５１１を有する。第２支持部５２は、筐体５３と、キャスタ５４と、押圧部５５と、を備える。 FIG. 5 is a partially enlarged view showing an example of the leg portion 5 of FIG. 6 is a cross-sectional view of the leg 5 of FIG. The leg portion 5 is disposed between the first support portion 51 that supports the top plate 4, the second support portion 52 that supports the first support portion 51, and the first support portion 51 and the second support portion 52. Load sensor 100. The 1st support part 51 has the recessed part 511 which accommodates the screw 15 of the load sensor 100 in a lower end. The second support part 52 includes a housing 53, a caster 54, and a pressing part 55.
　筐体５３は、第１支持部５１とキャスタ５４とを連結する筒状部材であり、中空部分５３１を有する。筐体５３の上端は荷重センサ１００及び第１支持部５１の下端に固定され、筐体５３の下端はキャスタ５４の上端に固定される。筐体５３の中空部分５３１には、荷重センサ１００の荷重受け部１４が収納される。 The housing 53 is a cylindrical member that connects the first support portion 51 and the casters 54, and has a hollow portion 531. The upper end of the casing 53 is fixed to the lower ends of the load sensor 100 and the first support portion 51, and the lower end of the casing 53 is fixed to the upper end of the casters 54. The load receiving portion 14 of the load sensor 100 is accommodated in the hollow portion 531 of the housing 53.
　キャスタ５４は、水平軸まわりに回転可能な車輪と、車輪を鉛直軸まわりに回転可能に支持する自在金具とを備える。キャスタ５４により、ベッド２００は容易に移動可能となる。 The caster 54 includes a wheel that can rotate about a horizontal axis, and a universal bracket that supports the wheel to rotate about a vertical axis. The bed 200 can be easily moved by the casters 54.
　押圧部５５は、キャスタ５４の上端から上方に延びる棒状部材であり、筐体５３の中空部分５３１に収納される。押圧部５５は、ベッド２００に荷重が加わった際に、その上端が荷重受け部１４を押圧可能な高さに設計される。 The pressing portion 55 is a rod-like member extending upward from the upper end of the caster 54 and is housed in the hollow portion 531 of the housing 53. The pressing portion 55 is designed to have a height at which the upper end of the pressing portion 55 can press the load receiving portion 14 when a load is applied to the bed 200.
　以上のような構成により、ベッド２００に人がのると、第１支持部５１により荷重センサ１００が押し下げられ、荷重受け部１４が押圧部５５により下方から押圧される。これにより、人の重さに応じた荷重が荷重受け部１４に加えられるため、荷重センサ１００は、人の重さ（荷重）を検出することができる。 With the above configuration, when a person is on the bed 200, the load sensor 100 is pushed down by the first support portion 51, and the load receiving portion 14 is pressed from below by the pressing portion 55. Thereby, since the load according to a person's weight is added to the load receiving part 14, the load sensor 100 can detect a person's weight (load).
　なお、上記実施形態に挙げた構成等に、その他の要素との組み合わせなど、ここで示した構成に本発明が限定されるものではない。これらの点に関しては、本発明の趣旨を逸脱しない範囲で変更可能であり、その応用形態に応じて適切に定めることができる。 It should be noted that the present invention is not limited to the configuration shown here, such as a combination with other elements in the configuration described in the above embodiment. These points can be changed without departing from the spirit of the present invention, and can be appropriately determined according to the application form.
　また、本国際出願は、２０１８年２月１５日に出願した日本国特許出願第２０１８－０２４９５３号に基づく優先権を主張するものであり、当該出願の全内容を本国際出願に援用する。 This international application claims priority based on Japanese Patent Application No. 2018-024953 filed on February 15, 2018, and the entire contents of the application are incorporated herein by reference.
１：起歪体
２：絶縁層
３：変換回路
４：天板
５：脚部
１１：第１部分
１２：第２部分
１３：開口部
１４：荷重受け部
１５：ネジ
２１：第１部分
２２：第２部分
５１：第１支持部
５２：第２支持部
５３：筐体
５４：キャスタ
５５：押圧部
１００：荷重センサ
２００：ベッド 1: Strain body 2: Insulating layer 3: Conversion circuit 4: Top plate 5: Leg part 11: First part 12: Second part 13: Opening part 14: Load receiving part 15: Screw 21: First part 22: 2nd part 51: 1st support part 52: 2nd support part 53: Case 54: Caster 55: Press part 100: Load sensor 200: Bed

Claims (16)

  1. 　荷重受け部を備えた起歪体と、
    　前記起歪体上に設けられた絶縁層と、
    　前記絶縁層上に設けられ、直列に接続された第１抵抗部及び第２抵抗部と、
    　前記第１抵抗部と前記第２抵抗部との間の電圧を出力する第１出力端子と、
    を備え、
    　前記第１抵抗部は、直列に接続され、円又は楕円である第１円の円周上に配置された複数の第１歪ゲージを備え、
    　前記第２抵抗部は、直列に接続され、円又は楕円である第２円の円周上に配置された複数の第２歪ゲージを備え、
    　前記第１円及び前記第２円は、前記荷重受け部を中心とする同心円又は同心楕円である
    荷重センサ。     A strain body having a load receiving portion;
    An insulating layer provided on the strain body;
    A first resistor part and a second resistor part provided on the insulating layer and connected in series;
    A first output terminal for outputting a voltage between the first resistor unit and the second resistor unit;
    With
    The first resistance unit includes a plurality of first strain gauges connected in series and disposed on a circumference of a first circle that is a circle or an ellipse,
    The second resistance portion includes a plurality of second strain gauges connected in series and disposed on a circumference of a second circle that is a circle or an ellipse,
    The first circle and the second circle are load sensors that are concentric circles or concentric ellipses centered on the load receiving portion.
  2. 　前記第１歪ゲージは、前記第１円の円周上に等間隔に配置される
    請求項１に記載の荷重センサ。     The load sensor according to claim 1, wherein the first strain gauges are arranged at equal intervals on a circumference of the first circle.
  3. 　前記第２歪ゲージは、前記第２円の円周上に等間隔に配置される
    請求項１又は請求項２に記載の荷重センサ。     The load sensor according to claim 1 or 2, wherein the second strain gauges are arranged at equal intervals on a circumference of the second circle.
  4. 　前記第２歪ゲージは、前記第１歪ゲージと前記第１円の中心との間に配置される
    請求項１から請求項３までのいずれか１項に記載の荷重センサ。     The load sensor according to any one of claims 1 to 3, wherein the second strain gauge is disposed between the first strain gauge and a center of the first circle.
  5. 　前記第１抵抗部は、２つ又は４つの前記第１歪ゲージを備える
    請求項１から請求項４までのいずれか１項に記載の荷重センサ。     The load sensor according to any one of claims 1 to 4, wherein the first resistance portion includes two or four of the first strain gauges.
  6. 　前記第２抵抗部は、２つ又は４つの前記第２歪ゲージを備える
    請求項１から請求項５までのいずれか１項に記載の荷重センサ。     The load sensor according to any one of claims 1 to 5, wherein the second resistance portion includes two or four of the second strain gauges.
  7. 　前記絶縁層上に設けられ、直列に接続された第３抵抗部及び第４抵抗部と、
    　前記第３抵抗部と前記第４抵抗部との間の電圧を出力する第２出力端子と、
    を備え、
    　前記第３抵抗部及び前記第４抵抗部は、前記第１抵抗部及び前記第２抵抗部と並列に接続され、
    　前記第３抵抗部は、直列に接続され、円又は楕円である第３円の円周上に配置された複数の第３歪ゲージを備え、
    　前記第４抵抗部は、直列に接続され、円又は楕円である第４円の円周上に配置された複数の第４歪ゲージを備え、
    　前記第３円及び前記第４円は、前記荷重受け部を中心とする同心円又は同心楕円である
    請求項１から請求項６までのいずれか１項に記載の荷重センサ。     A third resistor portion and a fourth resistor portion provided on the insulating layer and connected in series;
    A second output terminal that outputs a voltage between the third resistor unit and the fourth resistor unit;
    With
    The third resistor unit and the fourth resistor unit are connected in parallel to the first resistor unit and the second resistor unit,
    The third resistance portion includes a plurality of third strain gauges connected in series and arranged on the circumference of a third circle that is a circle or an ellipse,
    The fourth resistance unit includes a plurality of fourth strain gauges connected in series and arranged on the circumference of a fourth circle that is a circle or an ellipse,
    The load sensor according to any one of claims 1 to 6, wherein the third circle and the fourth circle are concentric circles or concentric ellipses centered on the load receiving portion.
  8. 　前記第３歪ゲージは、前記第３円の円周上に等間隔に配置される
    請求項７に記載の荷重センサ。     The load sensor according to claim 7, wherein the third strain gauges are arranged at equal intervals on a circumference of the third circle.
  9. 　前記第４歪ゲージは、前記第４円の円周上に等間隔に配置される
    請求項７又は請求項８に記載の荷重センサ。     The load sensor according to claim 7 or 8, wherein the fourth strain gauges are arranged at equal intervals on a circumference of the fourth circle.
  10. 　前記第４歪ゲージは、前記第３歪ゲージと前記第３円の中心との間に配置される
    請求項７から請求項９までのいずれか１項に記載の荷重センサ。     The load sensor according to any one of claims 7 to 9, wherein the fourth strain gauge is disposed between the third strain gauge and a center of the third circle.
  11. 　前記第３抵抗部は、２つ又は４つの前記第３歪ゲージを備える
    請求項７から請求項１０までのいずれか１項に記載の荷重センサ。     The load sensor according to any one of claims 7 to 10, wherein the third resistance unit includes two or four third strain gauges.
  12. 　前記第４抵抗部は、２つ又は４つの前記第４歪ゲージを備える
    請求項７から請求項１１までのいずれか１項に記載の荷重センサ。     The load sensor according to any one of claims 7 to 11, wherein the fourth resistance portion includes two or four of the fourth strain gauges.
  13. 　前記第１円及び前記第３円は同一であり、
    　前記第２円及び前記第４円は同一である
    請求項７から請求項１２までのいずれか１項に記載の荷重センサ。     The first circle and the third circle are the same,
    The load sensor according to any one of claims 7 to 12, wherein the second circle and the fourth circle are the same.
  14. 　前記第１歪ゲージ及び前記第３歪ゲージは、交互に等間隔に配置され、
    　前記第２歪ゲージ及び前記第４歪ゲージは、交互に等間隔に配置される
    請求項７から請求項１３までのいずれか１項に記載の荷重センサ。     The first strain gauge and the third strain gauge are alternately arranged at equal intervals,
    The load sensor according to any one of claims 7 to 13, wherein the second strain gauge and the fourth strain gauge are alternately arranged at equal intervals.
  15. 　前記起歪体は、外周部を固定される
    請求項１から請求項１４までのいずれか１項に記載の荷重センサ。     The load sensor according to any one of claims 1 to 14, wherein an outer peripheral portion of the strain generating body is fixed.
  16. 　天板と、
    　前記天板を支持する第１支持部と、
    　前記第１支持部を支持する第２支持部と、
    　前記第１支持部と前記第２支持部との間に配置され、前記第１支持部又は前記第２支持部から荷重を加えられる請求項１から請求項１５までのいずれか１項に記載の荷重センサと、
    を備える荷重検出装置。     With the top plate,
    A first support for supporting the top plate;
    A second support part for supporting the first support part;
    It is arrange | positioned between the said 1st support part and the said 2nd support part, The load is applied from the said 1st support part or the said 2nd support part, The any one of Claim 1-15 A load sensor;
    A load detection device comprising:
PCT/JP2018/045258 2018-02-15 2018-12-10 Load sensor and load detection device WO2019159512A1 (en)

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Citations (8)

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Publication number Priority date Publication date Assignee Title
JPS63302333A (en) * 1987-06-02 1988-12-09 Komatsu Ltd Pin type load cell
JP2009020096A (en) * 2007-06-14 2009-01-29 Panasonic Corp Strain detector
US20110067502A1 (en) * 2008-05-29 2011-03-24 Weigh Point Incorporated Load-Cell System
US8256306B1 (en) * 2009-09-02 2012-09-04 The Boeing Company High-capacity low-profile load cell for measuring compression force
WO2013108502A1 (en) * 2012-01-20 2013-07-25 昭和電工株式会社 Bed with load detection function, and load detector for bed
JP2013217815A (en) * 2012-04-11 2013-10-24 Yamato Scale Co Ltd Load cell
JP2013250161A (en) * 2012-05-31 2013-12-12 Aisin Seiki Co Ltd Load detection device
JP2017211297A (en) * 2016-05-26 2017-11-30 アイシン精機株式会社 Load detector

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63302333A (en) * 1987-06-02 1988-12-09 Komatsu Ltd Pin type load cell
JP2009020096A (en) * 2007-06-14 2009-01-29 Panasonic Corp Strain detector
US20110067502A1 (en) * 2008-05-29 2011-03-24 Weigh Point Incorporated Load-Cell System
US8256306B1 (en) * 2009-09-02 2012-09-04 The Boeing Company High-capacity low-profile load cell for measuring compression force
WO2013108502A1 (en) * 2012-01-20 2013-07-25 昭和電工株式会社 Bed with load detection function, and load detector for bed
JP2013217815A (en) * 2012-04-11 2013-10-24 Yamato Scale Co Ltd Load cell
JP2013250161A (en) * 2012-05-31 2013-12-12 Aisin Seiki Co Ltd Load detection device
JP2017211297A (en) * 2016-05-26 2017-11-30 アイシン精機株式会社 Load detector

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