JP2022014333A - Force sensor - Google Patents

Abstract

To suppress the enlargement of a size of a physique.SOLUTION: A force sensor 10 comprises a baseboard 22 whose face is directed to one side in a Z-axis direction. The force sensor 10 also comprises a pressure-receiving member 24 having a first pressure-receiving part 24A arranged at the one side in the Z-axis direction with respect to the baseboard 22 while opposing the baseboard 22 in the Z-axis direction, a second pressure-receiving part 24B arranged at the one side in the Z-axis direction with respect to the first pressure-receiving part 24A, and a connection part 24C for connecting the first pressure-receiving part 24A and the second pressure-receiving part 24B in the Z-axis direction. Furthermore, a distortion gauge 26 in which a resistance value changes by the deformation of the connection part 24C is arranged at the connection part 24C. A pressure-sensing gauge resistor 28C whose resistance value changes by being compressed between the baseboard 22 and the first pressure-receiving part 24A, is arranged between the baseboard 22 and the first pressure-receiving part 24A.SELECTED DRAWING: Figure 1

Description

本発明は、力センサに関する。 The present invention relates to a force sensor.

下記特許文献１には、Ｘ軸、Ｙ軸及びＺ軸方向の力とＸ軸、Ｙ軸及びＺ軸まわりのモーメントとを検出可能な６軸力センサが開示されている。この文献に記載された６軸力センサは、Ｚ軸方向を軸方向とする環状に形成されていると共にＺ軸方向に重ねて配置された２つの円板状部材を備えている。また、６軸力センサは、２つの円板状部材をつなぐ４つの脚を備えている。この脚は、Ｚ軸まわりの周方向に延びると共に一方の円板状部材に接続される横梁と、横梁からＺ軸方向に延びると共に他方の円板状部材に接続される縦梁と、を備えている。さらに、６軸力センサは、４つの脚の横梁にそれぞれ取り付けられた横梁用ひずみゲージと、４つの脚の縦梁にそれぞれ取り付けられた縦梁用ひずみゲージと、を備えている。そして、一方の円板状部材の他方の円板状部材に対する変位に伴う４つの脚部の変形が、横梁用ひずみゲージ及び縦梁用ひずみゲージによって検出される。この横梁用ひずみゲージ及び縦梁用ひずみゲージの出力値に基づいて、Ｘ軸、Ｙ軸及びＺ軸方向の力とＸ軸、Ｙ軸及びＺ軸まわりのモーメントとを検出及び算出することが可能となっている。 The following Patent Document 1 discloses a 6-axis force sensor capable of detecting a force in the X-axis, Y-axis and Z-axis directions and a moment around the X-axis, Y-axis and Z-axis. The 6-axis force sensor described in this document is formed in an annular shape with the Z-axis direction as the axial direction, and includes two disc-shaped members arranged so as to be overlapped in the Z-axis direction. Further, the 6-axis force sensor is provided with four legs connecting two disc-shaped members. The leg comprises a cross beam extending circumferentially around the Z axis and connected to one disc-shaped member, and a vertical beam extending from the cross beam in the Z-axis direction and connected to the other disc-shaped member. ing. Further, the 6-axis force sensor includes a cross beam strain gauge attached to each of the four leg cross beams and a vertical beam strain gauge attached to each of the four leg vertical beams. Then, the deformation of the four legs due to the displacement of one disc-shaped member with respect to the other disc-shaped member is detected by the strain gauge for the cross beam and the strain gauge for the vertical beam. Based on the output values of the cross beam strain gauge and the vertical beam strain gauge, it is possible to detect and calculate the force in the X-axis, Y-axis and Z-axis directions and the moment around the X-axis, Y-axis and Z-axis. It has become.

特開２００６－２７５６５０号公報Japanese Unexamined Patent Publication No. 2006-275650

上記特許文献１に記載された構成は、Ｘ軸、Ｙ軸及びＺ軸方向の力とＸ軸、Ｙ軸及びＺ軸まわりのモーメントとを検出するという観点では有用な構成ではある。しかしながら、力を検出する部分の構成によっては、力センサの体格の大型化を抑制することが望まれる場合がある。 The configuration described in Patent Document 1 is a useful configuration from the viewpoint of detecting a force in the X-axis, Y-axis, and Z-axis directions and a moment around the X-axis, Y-axis, and Z-axis. However, depending on the configuration of the portion that detects the force, it may be desired to suppress the increase in the size of the force sensor.

本発明は上記事実を考慮し、体格の大型化を抑制することができる力センサを得ることが目的である。 In consideration of the above facts, it is an object of the present invention to obtain a force sensor capable of suppressing an increase in body size.

請求項１記載の力センサは、Ｚ軸方向の一方側に面が向けられた基部材と、前記基部材に対してＺ軸方向の一方側に配置されていると共に前記基部材とＺ軸方向に対向して配置された第１受圧部と、前記第１受圧部に対してＺ軸方向の一方側に配置された第２受圧部と、前記第１受圧部と前記第２受圧部とをＺ軸方向につなぐ接続部と、を有する受圧部材と、前記接続部に設けられ、前記接続部が変形されることで抵抗値が変化する第１抵抗体と、前記基部材と前記第１受圧部との間に配置され、前記基部材と前記第１受圧部との間で圧縮されることで抵抗値が変化する第２抵抗体と、を備えている。 The force sensor according to claim 1 has a base member whose surface is directed to one side in the Z-axis direction and a base member arranged on one side in the Z-axis direction with respect to the base member and the base member and the Z-axis direction. A first pressure receiving portion arranged so as to face the first pressure receiving portion, a second pressure receiving portion arranged on one side in the Z-axis direction with respect to the first pressure receiving portion, and the first pressure receiving portion and the second pressure receiving portion. A pressure receiving member having a connecting portion connected in the Z-axis direction, a first resistor provided in the connecting portion and whose resistance value changes when the connecting portion is deformed, a base member and the first pressure receiving member. It is provided with a second resistor which is arranged between the portions and whose resistance value changes by being compressed between the base member and the first pressure receiving portion.

請求項１記載の力センサによれば、受圧部材側から基部材側へ力が入力されると、受圧部材の第１受圧部と第２受圧部とをつなぐ接続部が変形する。これにより、第１抵抗体の抵抗値が変化する。また、受圧部材側から基部材側へ力が入力されると、第２抵抗体が受圧部材の第１受圧部と基部材との間で圧縮される。これにより、第２抵抗体の抵抗値が変化する。このように、受圧部材の接続部の変形によって抵抗値が変化する第１抵抗体に加えて、受圧部材の第１受圧部と基部材との間で圧縮されることによって抵抗値が変化する第２抵抗体を設けることにより、すなわち、部材の変形量への依存度が少ない第２抵抗体を設けることにより、力センサの体格の大型化を抑制することができる。 According to the force sensor according to claim 1, when a force is input from the pressure receiving member side to the base member side, the connecting portion connecting the first pressure receiving portion and the second pressure receiving portion of the pressure receiving member is deformed. As a result, the resistance value of the first resistor changes. Further, when a force is input from the pressure receiving member side to the base member side, the second resistor is compressed between the first pressure receiving portion of the pressure receiving member and the base member. As a result, the resistance value of the second resistor changes. In this way, in addition to the first resistor whose resistance value changes due to the deformation of the connection portion of the pressure receiving member, the resistance value changes due to compression between the first pressure receiving portion of the pressure receiving member and the base member. By providing the two resistors, that is, by providing the second resistor that is less dependent on the amount of deformation of the member, it is possible to suppress an increase in the physique of the force sensor.

請求項２記載の力センサは、請求項１に記載の力センサにおいて、前記基部材及び前記受圧部材には、Ｚ軸方向に貫通する孔が形成されている。 The force sensor according to claim 2 is the force sensor according to claim 1, wherein a hole penetrating in the Z-axis direction is formed in the base member and the pressure receiving member.

請求項２記載の力センサによれば、基部材及び受圧部材に形成された孔にボルト等を挿通して使用することができる。 According to the force sensor according to claim 2, bolts or the like can be inserted into holes formed in the base member and the pressure receiving member for use.

請求項３記載の力センサは、請求項１又は請求項２に記載の力センサにおいて、前記第１抵抗体及び前記第２抵抗体は、Ｚ軸方向のまわりの周方向の４か所に等間隔に配置されている。 The force sensor according to claim 3 is the force sensor according to claim 1 or 2, wherein the first resistor and the second resistor are located at four locations in the circumferential direction around the Z-axis direction. Arranged at intervals.

請求項３記載の力センサによれば、第１抵抗体及び第２抵抗体が、Ｚ軸方向のまわりの周方向の４か所に等間隔に配置されていることにより、Ｚ軸方向の力に加えて、Ｚ軸と直交するＸ軸方向の力と、Ｚ軸及びＸ軸と直交するＹ軸方向の力とを検出することができる。 According to the force sensor according to claim 3, the first resistor and the second resistor are arranged at four locations in the circumferential direction around the Z-axis direction at equal intervals, so that the force in the Z-axis direction is applied. In addition, a force in the X-axis direction orthogonal to the Z-axis and a force in the Y-axis direction orthogonal to the Z-axis and the X-axis can be detected.

本発明に係る力センサは、体格の大型化を抑制することができる、という優れた効果を有する。 The force sensor according to the present invention has an excellent effect of being able to suppress an increase in body size.

本実施形態の力センサ及びこの力センサが設けられた締結部を示す分解斜視図である。It is an exploded perspective view which shows the force sensor of this embodiment and the fastening part provided with this force sensor. 本実施形態のセンサを模式的に示す側面図である。It is a side view which shows typically the sensor of this embodiment. 受圧部材を模式的に示す側面図である。It is a side view which shows typically the pressure receiving member. 感圧素子を模式的に示す平面図である。It is a top view which shows the pressure-sensitive element schematically. 他の形態の受圧部材を示す斜視図である。It is a perspective view which shows the pressure receiving member of another form. 他の形態の受圧部材を示す側面図である。It is a side view which shows the pressure receiving member of another form.

図１～図４を用いて、本発明の実施形態に係る力センサについて説明する。 The force sensor according to the embodiment of the present invention will be described with reference to FIGS. 1 to 4.

図１に示されるように、本実施形態の力センサ１０は、第１の部材１２と第２の部材１４とがボルト１６及びナット１８を介して固定される締結部２０に設けることができる。なお、ボルト１６の軸方向及び力センサ１０においてボルト１６が挿通される方向をＺ軸方向とし、Ｚ軸方向と直交する方向をＸ軸方向とし、Ｚ軸方向及びＸ軸方向と直交する方向をＹ軸方向とする。また、Ｚ軸方向の一方側を矢印Ｚで示し、Ｘ軸方向の一方側を矢印Ｘで示し、Ｙ軸方向の一方側を矢印Ｙで示す。 As shown in FIG. 1, the force sensor 10 of the present embodiment can be provided at the fastening portion 20 in which the first member 12 and the second member 14 are fixed via the bolt 16 and the nut 18. The axial direction of the bolt 16 and the direction in which the bolt 16 is inserted in the force sensor 10 are defined as the Z-axis direction, the direction orthogonal to the Z-axis direction is defined as the X-axis direction, and the directions orthogonal to the Z-axis direction and the X-axis direction are defined. It is in the Y-axis direction. Further, one side in the Z-axis direction is indicated by an arrow Z, one side in the X-axis direction is indicated by an arrow X, and one side in the Y-axis direction is indicated by an arrow Y.

図１～図３に示されるように、力センサ１０は、板状に形成された基部材としての基板２２と、基板２２に対してＺ軸方向の一方側に配置された受圧部材２４と、受圧部材２４に取付けられた第１抵抗体としてのひずみゲージ２６と、基板２２と受圧部材２４との間に配置された感圧素子２８と、を備えている。 As shown in FIGS. 1 to 3, the force sensor 10 includes a substrate 22 as a base member formed in a plate shape, and a pressure receiving member 24 arranged on one side in the Z-axis direction with respect to the substrate 22. It includes a strain gauge 26 as a first resistor attached to the pressure receiving member 24, and a pressure sensitive element 28 arranged between the substrate 22 and the pressure receiving member 24.

図１及び図２に示されるように、基板２２は、一例として金属材料を用いて形成されている。この基板２２は、Ｚ軸方向の一方側から見てＹ軸方向の一方側の端が円形状に湾曲された形状に形成されていると共にＹ軸方向の他方側の端が四角形状に形成されている。この基板２２のＺ軸方向の一方側の面及び他方側の面は、Ｘ軸方向及びＹ軸方向に沿って互いに平行に延在している。また、基板２２には、ボルト１６が挿通される孔としての挿通孔２２Ａが形成されている。 As shown in FIGS. 1 and 2, the substrate 22 is formed by using a metal material as an example. The substrate 22 is formed so that one end in the Y-axis direction is curved in a circular shape when viewed from one side in the Z-axis direction, and the other end in the Y-axis direction is formed in a quadrangular shape. ing. One surface and the other surface of the substrate 22 in the Z-axis direction extend in parallel with each other along the X-axis direction and the Y-axis direction. Further, the substrate 22 is formed with an insertion hole 22A as a hole through which the bolt 16 is inserted.

図２及び図３に示されるように、受圧部材２４は、一例として金属材料を用いて形成されている。この受圧部材２４は、基板２２に対してＺ軸方向の一方側に配置されていると共に基板２２とＺ軸方向に対向して配置される第１受圧部２４Ａと、第１受圧部２４Ａに対してＺ軸方向の一方側に配置された第２受圧部２４Ｂと、を備えている。第１受圧部２４Ａ及び第２受圧部２４Ｂは、Ｚ軸方向を軸方向とする環状の円板状に形成されている。第１受圧部２４Ａ及び第２受圧部２４ＢのＺ軸方向への厚み寸法Ｔ１、Ｔ２は、互いに同じ寸法に設定されている。また、受圧部材２４は、第１受圧部２４Ａの径方向内側の端部と第２受圧部２４Ｂの径方向内側の端部とをＺ軸方向につなぐ円筒状の接続部２４Ｃを備えている。この接続部２４Ｃの径方向（Ｘ軸方向及びＹ軸方向）への厚み寸法Ｔ３は周方向の各部で一定の寸法に設定されている。なお、図３においては、接続部２４ＣのＺ軸方向への寸法を誇張して表現している。また、受圧部材２４の内周部には、ボルト１６が挿通される孔としての挿通孔２４Ｄが形成されている。 As shown in FIGS. 2 and 3, the pressure receiving member 24 is formed by using a metal material as an example. The pressure receiving member 24 is arranged on one side in the Z-axis direction with respect to the substrate 22 and is arranged so as to face the substrate 22 in the Z-axis direction with respect to the first pressure receiving portion 24A and the first pressure receiving portion 24A. It is provided with a second pressure receiving portion 24B arranged on one side in the Z-axis direction. The first pressure receiving portion 24A and the second pressure receiving portion 24B are formed in the shape of an annular disk whose axial direction is the Z-axis direction. The thickness dimensions T1 and T2 of the first pressure receiving portion 24A and the second pressure receiving portion 24B in the Z-axis direction are set to the same dimensions. Further, the pressure receiving member 24 includes a cylindrical connecting portion 24C that connects the radial inner end portion of the first pressure receiving portion 24A and the radial inner end portion of the second pressure receiving portion 24B in the Z-axis direction. The thickness dimension T3 in the radial direction (X-axis direction and Y-axis direction) of the connecting portion 24C is set to a constant dimension in each portion in the circumferential direction. In FIG. 3, the dimension of the connecting portion 24C in the Z-axis direction is exaggerated. Further, an insertion hole 24D is formed in the inner peripheral portion of the pressure receiving member 24 as a hole through which the bolt 16 is inserted.

ひずみゲージ２６は、Ｚ軸方向へのひずみを検出できる方向へ向けられた状態で受圧部材２４の接続部２４Ｃの外周面に接合される単軸ひずみゲージである。本実施形態では、Ｚ軸方向に間隔をあけて配置されたひずみゲージ２６（Ｒ１）及びひずみゲージ２６（Ｒ２）が、接続部２４Ｃの外周面におけるＸ軸方向一方側の部分に接合されている。また、Ｚ軸方向に間隔をあけて配置されたひずみゲージ２６（Ｒ３）及びひずみゲージ２６（Ｒ４）が、接続部２４Ｃの外周面におけるＸ軸方向他方側の部分に接合されている。また、本実施形態では、これらのひずみゲージ２６（Ｒ１，Ｒ２、Ｒ３、Ｒ４）によってブリッジ回路が組まれている。 The strain gauge 26 is a uniaxial strain gauge joined to the outer peripheral surface of the connection portion 24C of the pressure receiving member 24 in a state of being directed in a direction in which strain in the Z-axis direction can be detected. In the present embodiment, the strain gauges 26 (R1) and the strain gauges 26 (R2) arranged at intervals in the Z-axis direction are joined to one side of the outer peripheral surface of the connecting portion 24C in the X-axis direction. .. Further, the strain gauges 26 (R3) and the strain gauges 26 (R4) arranged at intervals in the Z-axis direction are joined to the other side portion in the X-axis direction on the outer peripheral surface of the connecting portion 24C. Further, in the present embodiment, a bridge circuit is assembled by these strain gauges 26 (R1, R2, R3, R4).

また、Ｚ軸方向に間隔をあけて配置されたひずみゲージ２６（Ｒ１）及びひずみゲージ２６（Ｒ２）が、接続部２４Ｃの外周面におけるＹ軸方向一方側の部分に接合されている。また、Ｚ軸方向に間隔をあけて配置されたひずみゲージ２６（Ｒ３）及びひずみゲージ２６（Ｒ４）が、接続部２４Ｃの外周面におけるＹ軸方向他方側の部分に接合されている。また、本実施形態では、これらのひずみゲージ２６（Ｒ１，Ｒ２、Ｒ３、Ｒ４）によってブリッジ回路が組まれている。なお、図３においては、接続部２４Ｃの外周面におけるＹ軸方向一方側の部分に接合されたひずみゲージ２６（Ｒ１）及びひずみゲージ２６（Ｒ２）が見えなくなっている。 Further, the strain gauges 26 (R1) and the strain gauges 26 (R2) arranged at intervals in the Z-axis direction are joined to a portion on one side in the Y-axis direction on the outer peripheral surface of the connecting portion 24C. Further, the strain gauges 26 (R3) and the strain gauges 26 (R4) arranged at intervals in the Z-axis direction are joined to the other side portion in the Y-axis direction on the outer peripheral surface of the connecting portion 24C. Further, in the present embodiment, a bridge circuit is assembled by these strain gauges 26 (R1, R2, R3, R4). In FIG. 3, the strain gauge 26 (R1) and the strain gauge 26 (R2) joined to one side of the outer peripheral surface of the connecting portion 24C in the Y-axis direction are not visible.

以上説明したように、本実施形態では、Ｚ軸方向に間隔をあけて配置された一対のひずみゲージ２６が、Ｚ軸方向のまわりに９０°間隔で設けられた構成となっている。 As described above, in the present embodiment, the pair of strain gauges 26 arranged at intervals in the Z-axis direction are provided around the Z-axis direction at intervals of 90 °.

図１及び図２に示されるように、感圧素子２８は、基板２２と受圧部材２４の第１受圧部２４Ａとの間に配置される薄肉の板状に形成されている。この感圧素子２８のＺ軸方向から見た形状は、基板２２と対応する形状となっている。また、感圧素子２８には、ボルト１６が挿通される孔としての挿通孔２８Ａが形成されている。 As shown in FIGS. 1 and 2, the pressure sensitive element 28 is formed in the shape of a thin plate arranged between the substrate 22 and the first pressure receiving portion 24A of the pressure receiving member 24. The shape of the pressure sensitive element 28 seen from the Z-axis direction corresponds to the substrate 22. Further, the pressure-sensitive element 28 is formed with an insertion hole 28A as a hole through which the bolt 16 is inserted.

ここで、図４に示されるように、感圧素子２８における挿通孔２８Ａの周縁部は、基板２２と受圧部材２４の第１受圧部２４Ａとの間で圧縮される感圧部２８Ｂとなっている。なお、図４においては、感圧素子２８における感圧部２８Ｂの周縁部が模式的に示されている。また、図４における感圧部２８Ｂは、感圧素子２８において二点鎖線で描かれたか仮想円Ｃ１と二点鎖線で描かれた仮想円Ｃ２との間の領域のことである。 Here, as shown in FIG. 4, the peripheral edge portion of the insertion hole 28A in the pressure sensitive element 28 becomes the pressure sensitive portion 28B compressed between the substrate 22 and the first pressure receiving portion 24A of the pressure receiving member 24. There is. In addition, in FIG. 4, the peripheral edge portion of the pressure sensitive portion 28B in the pressure sensitive element 28 is schematically shown. Further, the pressure-sensitive portion 28B in FIG. 4 is a region between the virtual circle C1 drawn by the two-dot chain line or the virtual circle C2 drawn by the two-dot chain line in the pressure-sensitive element 28.

感圧部２８Ｂには、第２抵抗体としての４つの感圧ゲージ抵抗２８Ｃが設けられている。この４つの感圧ゲージ抵抗２８Ｃは、Ｚ軸方向のまわりに９０°間隔で設けられている。また、この４つの感圧ゲージ抵抗２８Ｃは、Ｚ軸方向から見て前述の一対のひずみゲージ２６（Ｒ１、Ｒ２）及び一対のひずみゲージ２６（Ｒ３、Ｒ４）とそれぞれ同じ位置に配置されている。 The pressure sensitive portion 28B is provided with four pressure sensitive gauge resistances 28C as second resistors. The four pressure-sensitive gauge resistors 28C are provided around the Z-axis direction at intervals of 90 °. Further, the four pressure-sensitive gauge resistors 28C are arranged at the same positions as the pair of strain gauges 26 (R1, R2) and the pair of strain gauges 26 (R3, R4) described above when viewed from the Z-axis direction. ..

また、感圧素子２８において感圧部２８Ｂよりも径方向外側には、ダミーゲージとして機能する４つの温度補償用ゲージ抵抗２８Ｄが設けられている。この４つの温度補償用ゲージ抵抗２８Ｄは、感圧部２８Ｂが圧縮されることによる影響を受けない部分又は当該影響が小さい部分に設けられている。また、この４つの温度補償用ゲージ抵抗２８Ｄは、４つの感圧ゲージ抵抗２８Ｃに隣接する位置にそれぞれ設けられている。さらに、４つの温度補償用ゲージ抵抗２８Ｄと４つの感圧ゲージ抵抗２８Ｃとは、それぞれ２ゲージ法により結線されている。 Further, in the pressure sensitive element 28, four temperature compensating gauge resistors 28D that function as dummy gauges are provided on the radial side of the pressure sensitive portion 28B. The four temperature compensating gauge resistances 28D are provided in a portion that is not affected by the compression of the pressure sensitive portion 28B or a portion where the influence is small. Further, the four temperature compensating gauge resistances 28D are provided at positions adjacent to the four pressure sensitive gauge resistances 28C, respectively. Further, the four temperature compensating gauge resistances 28D and the four pressure sensitive gauge resistances 28C are each connected by a two-gauge method.

（本実施形態の作用並びに効果）
次に、本実施形態の作用並びに効果について説明する。 (Action and effect of this embodiment)
Next, the operation and effect of this embodiment will be described.

図１及び図２に示されるように、本実施形態の力センサ１０は、第１の部材１２と第２の部材１４とがボルト１６及びナット１８を介して固定される締結部２０に設けられることにより、当該締結部２０の軸力等を解析することができる。 As shown in FIGS. 1 and 2, the force sensor 10 of the present embodiment is provided at the fastening portion 20 in which the first member 12 and the second member 14 are fixed via the bolt 16 and the nut 18. This makes it possible to analyze the axial force and the like of the fastening portion 20.

詳述すると、力センサ１０は、第１の部材１２と第２の部材１４との間に配置される。そして、第１の部材１２、第２の部材１４及び力センサ１０の各挿通孔２２Ａ、２４Ｄ、２８Ａにボルト１６が挿通された状態で、当該ボルト１６がナット１８に螺合される。これにより、力センサ１０が第１の部材１２と第２の部材１４との間に配置された状態で、第１の部材１２と第２の部材１４とがボルト１６及びナット１８を介して固定される。 More specifically, the force sensor 10 is arranged between the first member 12 and the second member 14. Then, with the bolt 16 inserted into the insertion holes 22A, 24D, 28A of the first member 12, the second member 14, and the force sensor 10, the bolt 16 is screwed into the nut 18. As a result, the first member 12 and the second member 14 are fixed via the bolt 16 and the nut 18 in a state where the force sensor 10 is arranged between the first member 12 and the second member 14. Will be done.

ここで、ボルト１６がナット１８に螺合された状態で、Ｚ軸方向への軸力が締結部２０に生じると、受圧部材２４の接続部２４Ｃに設けられた各々の感圧ゲージ抵抗２８Ｃの抵抗値が変化する。この各々の感圧ゲージ抵抗２８Ｃの抵抗値の変化によってＺ軸方向への軸力を検出及び算出することができる。本実施形態では、各々の感圧ゲージ抵抗２８Ｃの抵抗値の変化量の和を主に用いて、すなわち、各々の感圧ゲージ抵抗２８Ｃを有する各々のブリッジ回路の出力値（出力電圧）の和を主に用いて、Ｚ軸方向への軸力を検出及び算出している。なお、Ｚ軸方向への軸力が締結部２０に生じると、受圧部材２４の第１受圧部２４Ａと第２受圧部２４Ｂとをつなぐ接続部２４Ｃが軸方向に変形する。これにより、接続部２４Ｃに接合された各々のひずみゲージ２６の抵抗値は変化するが、この抵抗値の変化は互いにほぼ同じである。そのため、各々のひずみゲージ２６を有する各々のブリッジ回路の出力値（出力電圧）の変化は小さくなっている。 Here, when an axial force in the Z-axis direction is generated in the fastening portion 20 in a state where the bolt 16 is screwed into the nut 18, each pressure-sensitive gauge resistance 28C provided in the connection portion 24C of the pressure receiving member 24 The resistance value changes. Axial force in the Z-axis direction can be detected and calculated by changing the resistance value of each of the pressure-sensitive gauge resistors 28C. In this embodiment, the sum of the changes in the resistance value of each pressure-sensitive gauge resistor 28C is mainly used, that is, the sum of the output values (output voltage) of each bridge circuit having each pressure-sensitive gauge resistance 28C. Is mainly used to detect and calculate the axial force in the Z-axis direction. When an axial force in the Z-axis direction is generated in the fastening portion 20, the connecting portion 24C connecting the first pressure receiving portion 24A and the second pressure receiving portion 24B of the pressure receiving member 24 is deformed in the axial direction. As a result, the resistance value of each strain gauge 26 joined to the connecting portion 24C changes, but the change in the resistance value is almost the same as each other. Therefore, the change in the output value (output voltage) of each bridge circuit having each strain gauge 26 is small.

また、Ｘ軸方向への軸力が締結部２０に生じると、接続部２４Ｃの外周面におけるＸ軸方向一方側の部分及び他方側の部分に接合されたひずみゲージ２６（Ｒ１，Ｒ２、Ｒ３、Ｒ４）の抵抗値が主に変化して、これらのひずみゲージ２６（Ｒ１，Ｒ２、Ｒ３、Ｒ４）を有するブリッジ回路の出力値（出力電圧）が主に変化する。この出力値を主としてＸ軸方向への軸力を検出及び算出している。 Further, when an axial force in the X-axis direction is generated in the fastening portion 20, the strain gauge 26 (R1, R2, R3, The resistance value of R4) mainly changes, and the output value (output voltage) of the bridge circuit having these strain gauges 26 (R1, R2, R3, R4) mainly changes. This output value is mainly used to detect and calculate the axial force in the X-axis direction.

また、Ｙ軸方向への軸力が締結部２０に生じると、接続部２４Ｃの外周面におけるＹ軸方向一方側の部分及び他方側の部分に接合されたひずみゲージ２６（Ｒ１，Ｒ２、Ｒ３、Ｒ４）の抵抗値が主に変化して、これらのひずみゲージ２６（Ｒ１，Ｒ２、Ｒ３、Ｒ４）を有するブリッジ回路の出力値（出力電圧）が主に変化する。この出力値を主としてＹ軸方向への軸力を検出及び算出している。 Further, when an axial force in the Y-axis direction is generated in the fastening portion 20, the strain gauge 26 (R1, R2, R3, The resistance value of R4) mainly changes, and the output value (output voltage) of the bridge circuit having these strain gauges 26 (R1, R2, R3, R4) mainly changes. This output value is mainly used to detect and calculate the axial force in the Y-axis direction.

また、Ｘ軸方向への曲げモーメントが締結部２０に生じると、受圧部材２４の接続部２４Ｃに設けられた各々の感圧ゲージ抵抗２８ＣのうちＺ軸方向から見てＸ軸上に配置された２つの感圧ゲージ抵抗２８Ｃの抵抗値及び接続部２４Ｃの外周面におけるＸ軸方向一方側の部分及び他方側の部分に接合されたひずみゲージ２６（Ｒ１，Ｒ２、Ｒ３、Ｒ４）の抵抗値が主に変化する。そして、上記の２つの感圧ゲージ抵抗２８Ｃを有するブリッジ回路の出力値（出力電圧）の変化量及び上記のひずみゲージ２６（Ｒ１，Ｒ２、Ｒ３、Ｒ４）を有するブリッジ回路の出力値（出力電圧）を主としてＸ軸方向への曲げモーメントを検出及び算出している。 Further, when a bending moment in the X-axis direction is generated in the fastening portion 20, the pressure-sensitive gauge resistance 28C provided in the connecting portion 24C of the pressure receiving member 24 is arranged on the X-axis when viewed from the Z-axis direction. The resistance values of the two pressure-sensitive gauge resistors 28C and the resistance values of the strain gauges 26 (R1, R2, R3, R4) joined to the one-sided portion and the other-sided portion in the X-axis direction on the outer peripheral surface of the connecting portion 24C. Mainly changes. Then, the amount of change in the output value (output voltage) of the bridge circuit having the above two pressure-sensitive gauge resistances 28C and the output value (output voltage) of the bridge circuit having the strain gauge 26 (R1, R2, R3, R4) described above. ) Is mainly used to detect and calculate the bending moment in the X-axis direction.

また、Ｙ軸方向への曲げモーメントが締結部２０に生じると、受圧部材２４の接続部２４Ｃに設けられた各々の感圧ゲージ抵抗２８ＣのうちＺ軸方向から見てＹ軸上に配置された２つの感圧ゲージ抵抗２８Ｃの抵抗値及び接続部２４Ｃの外周面におけるＹ軸方向一方側の部分及び他方側の部分に接合されたひずみゲージ２６（Ｒ１，Ｒ２、Ｒ３、Ｒ４）の抵抗値が主に変化する。そして、上記の２つの感圧ゲージ抵抗２８Ｃを有するブリッジ回路の出力値（出力電圧）の変化量及び上記のひずみゲージ２６（Ｒ１，Ｒ２、Ｒ３、Ｒ４）を有するブリッジ回路の出力値（出力電圧）を主としてＸ軸方向への曲げモーメントを検出及び算出している。 Further, when a bending moment in the Y-axis direction is generated in the fastening portion 20, the pressure-sensitive gauge resistance 28C provided in the connection portion 24C of the pressure receiving member 24 is arranged on the Y-axis when viewed from the Z-axis direction. The resistance values of the two pressure-sensitive gauge resistors 28C and the resistance values of the strain gauges 26 (R1, R2, R3, R4) joined to the one-sided portion and the other-sided portion in the Y-axis direction on the outer peripheral surface of the connecting portion 24C. Mainly changes. Then, the amount of change in the output value (output voltage) of the bridge circuit having the above two pressure-sensitive gauge resistances 28C and the output value (output voltage) of the bridge circuit having the strain gauge 26 (R1, R2, R3, R4) described above. ) Is mainly used to detect and calculate the bending moment in the X-axis direction.

以上、各軸力及びモーメントの検出及び算出方法の一部について説明したが、以下に各軸力及びモーメントの算出方法についてまとめる。 The above is a partial description of the methods for detecting and calculating each axial force and moment, but the methods for calculating each axial force and moment are summarized below.

先ず、Ｘ軸方向への軸力、Ｙ軸方向への軸力、Ｚ軸方向への軸力、Ｘ軸方向への曲げモーメント、Ｙ軸方向への曲げモーメント、Ｚ軸方向への曲げモーメントをそれぞれＦ_Ｘ、Ｆ_Ｙ、Ｆ_Ｚ、Ｍ_Ｘ、Ｍ_Ｙ、Ｍ_Ｚとする。また、接続部２４Ｃの外周面におけるＸ軸方向一方側の部分及び他方側の部分に接合されたひずみゲージ２６（Ｒ１，Ｒ２、Ｒ３、Ｒ４）を有するブリッジ回路の出力値（出力電圧）をε_１とし、接続部２４Ｃの外周面におけるＹ軸方向一方側の部分及び他方側の部分に接合されたひずみゲージ２６（Ｒ１，Ｒ２、Ｒ３、Ｒ４）を有するブリッジ回路の出力値（出力電圧）をε_２とする。さらに、受圧部材２４の接続部２４Ｃに設けられた各々の感圧ゲージ抵抗２８Ｃを有する各々のブリッジ回路の出力値（出力電圧）をそれぞれＶ１、Ｖ１、Ｖ３、Ｖ４とする。すると、Ｆ_Ｘ、Ｆ_Ｙ、Ｆ_Ｚ、Ｍ_Ｘ、Ｍ_Ｙ、Ｍ_Ｚは、以下の式で表すことができる。なお、ａ１１～ａ６６は、力センサ１０について校正を行うことによって得られた校正係数である。 First, the axial force in the X-axis direction, the axial force in the Y-axis direction, the axial force in the Z-axis direction, the bending moment in the X-axis direction, the bending moment in the Y-axis direction, and the bending moment in the Z-axis direction are calculated. _Let it be FX, _FY , F _Z , _{MX, MY, and M Z , respectively} . Further, the output value (output voltage) of the bridge circuit having the strain gauges 26 (R1, R2, R3, R4) joined to the one-sided portion and the other-sided portion in the X-axis direction on the outer peripheral surface of the connecting portion 24C is ε. The output value (output voltage) of the bridge circuit having the strain gauges 26 (R1, R2, R3, R4) joined to the one-sided portion and the other-sided portion in the Y-axis direction on the outer peripheral surface of the connecting portion 24C is set to ₁ . Let it be ε ₂ . Further, the output values (output voltages) of the respective bridge circuits having the respective pressure-sensitive gauge resistances 28C provided in the connection portion 24C of the pressure receiving member 24 are set to V1, V1, V3, and V4, respectively. Then, _{FX, FY, F Z, MX, MY, and M Z can be expressed by the} following equations. In addition, a11 to a66 are calibration coefficients obtained by calibrating the force sensor 10.

すなわち、Ｆ_Ｘ＝ａ_１１・ε_１＋ａ_１２・ε_２＋ａ_１３・Ｖ_１＋ａ_１４・Ｖ_２＋ａ_１５・Ｖ_３＋ａ_１６・Ｖ_４で算出される。これと同様に、Ｍ_Ｘ＝ａ_４１・ε_１＋ａ_４２・ε_２＋ａ_４３・Ｖ_１＋ａ_４４・Ｖ_２＋ａ_４５・Ｖ_３＋ａ_４６・Ｖ_４で算出される。なお、Ｆ_Ｙ、Ｆ_Ｚ、Ｍ_Ｙ、Ｍ_Ｚについても同様に算出される。 That is, it is calculated by _FX = a ₁₁ · ε ₁ + a ₁₂ · ε ₂ + a ₁₃ · V ₁ + a ₁₄ · V ₂ + a ₁₅ · V ₃ + a ₁₆ · V ₄ . Similarly, it is calculated by _MX = a ₄₁ · ε ₁ + a ₄₂ · ε ₂ + a ₄₃ · V ₁ + a ₄₄ · V ₂ + a ₄₅ · V ₃ + a ₄₆ · V ₄ . The same applies to _FY , F _Z , _MY , and M _Z.

なお、各校正係数の値が近似する値である場合においては、各軸力や各モーメントの検出感度にばらつきが生じる可能性がある。そこで、本実施形態では、４つの感圧ゲージ抵抗２８ＣをＺ軸方向のまわりに９０°間隔で配置すると共に、この４つの感圧ゲージ抵抗２８ＣをＺ軸方向から見て一対のひずみゲージ２６（Ｒ１、Ｒ２）及び一対のひずみゲージ２６（Ｒ３、Ｒ４）とそれぞれ同じ位置に配置している。これにより、Ｘ軸方向への軸力及びＹ軸方向への軸力に対してはひずみゲージ２６の感度が高くなるように、各モーメントに対しては感圧ゲージ抵抗２８Ｃの感度が高くなるように、各校正係数の差異がでるようになっている。 When the values of the calibration coefficients are close to each other, the detection sensitivity of each axial force and each moment may vary. Therefore, in the present embodiment, the four pressure-sensitive gauge resistances 28C are arranged around the Z-axis direction at 90 ° intervals, and the four pressure-sensitive gauge resistances 28C are arranged as a pair of strain gauges 26 (strain gauges 26) when viewed from the Z-axis direction. It is arranged at the same position as R1, R2) and the pair of strain gauges 26 (R3, R4), respectively. As a result, the sensitivity of the strain gauge 26 is increased with respect to the axial force in the X-axis direction and the axial force in the Y-axis direction, and the sensitivity of the pressure-sensitive gauge resistor 28C is increased with respect to each moment. In addition, the difference in each calibration coefficient appears.

以上説明したように、本実施形態の力センサ１０では、Ｘ軸方向への軸力、Ｙ軸方向への軸力、Ｚ軸方向への軸力、Ｘ軸方向への曲げモーメント、Ｙ軸方向への曲げモーメント、Ｚ軸方向への曲げモーメントをそれぞれ検出することができる。なお、力センサ１０の構成は、３軸力センサとするか又は６軸力センサとするかによって適宜設定すればよい。 As described above, in the force sensor 10 of the present embodiment, the axial force in the X-axis direction, the axial force in the Y-axis direction, the axial force in the Z-axis direction, the bending moment in the X-axis direction, and the Y-axis direction. It is possible to detect the bending moment to and the bending moment in the Z-axis direction, respectively. The configuration of the force sensor 10 may be appropriately set depending on whether it is a 3-axis force sensor or a 6-axis force sensor.

また、本実施形態の力センサ１０では、受圧部材２４の接続部２４Ｃの変形によって抵抗値が変化するひずみゲージ２６に加えて、受圧部材２４の第１受圧部２４Ａと基板２２との間で圧縮されることによって抵抗値が変化する感圧ゲージ抵抗２８Ｃを設けることにより、すなわち、部材の変形量への依存度が少ない感圧ゲージ抵抗２８Ｃを設けることにより、力センサ１０の体格の大型化を抑制することができる。また、このように構成することで、力センサ１０の出力値の安定性の向上と耐久性の向上を図ることができる。 Further, in the force sensor 10 of the present embodiment, in addition to the strain gauge 26 whose resistance value changes due to the deformation of the connection portion 24C of the pressure receiving member 24, compression is performed between the first pressure receiving portion 24A of the pressure receiving member 24 and the substrate 22. By providing a pressure-sensitive gauge resistance 28C whose resistance value changes as a result of the movement, that is, by providing a pressure-sensitive gauge resistance 28C that is less dependent on the amount of deformation of the member, the physique of the force sensor 10 can be increased. It can be suppressed. Further, with such a configuration, it is possible to improve the stability and durability of the output value of the force sensor 10.

なお、本実施形態では、ボルト１６を挿通可能な力センサ１０について説明したが、本発明はこれに限定されない。ボルト１６を挿通可能とするか否かについては、力センサが設けられる部分の構成を考慮して適宜設定すればよい。 In the present embodiment, the force sensor 10 through which the bolt 16 can be inserted has been described, but the present invention is not limited thereto. Whether or not the bolt 16 can be inserted may be appropriately set in consideration of the configuration of the portion where the force sensor is provided.

また、本実施形態では、第１受圧部２４Ａの径方向内側の端部と第２受圧部２４Ｂの径方向内側の端部とをＺ軸方向につなぐ円筒状の接続部２４Ｃを有する受圧部材２４を用いた例について説明したが、本発明はこれに限定されない。例えば、図５及び図６に示されるように、第１受圧部２４Ａの径方向内側の端部と第２受圧部２４Ｂの径方向内側の端部とをＺ軸方向につなぐと共にＺ軸方向のまわりに等間隔に配列された複数の接続部２４Ｃを有する受圧部材２４を用いた構成としてもよい。 Further, in the present embodiment, the pressure receiving member 24 has a cylindrical connecting portion 24C that connects the radially inner end portion of the first pressure receiving portion 24A and the radially inner end portion of the second pressure receiving portion 24B in the Z-axis direction. However, the present invention is not limited to this. For example, as shown in FIGS. 5 and 6, the radially inner end of the first pressure receiving portion 24A and the radially inner end of the second pressure receiving portion 24B are connected in the Z-axis direction and in the Z-axis direction. A pressure receiving member 24 having a plurality of connecting portions 24C arranged around the same space may be used.

以上、本発明の一実施形態について説明したが、本発明は、上記に限定されるものでなく、その主旨を逸脱しない範囲内において上記以外にも種々変形して実施することが可能であることは勿論である。 Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and can be modified in various ways other than the above within a range not deviating from the gist thereof. Of course.

１０ 力センサ
２２ 基板（基部材）
２２Ａ 挿通孔（孔）
２４ 受圧部材
２４Ａ 第１受圧部
２４Ｂ 第２受圧部
２４Ｃ 接続部
２４Ｄ 挿通孔（孔）
２６ ひずみゲージ（第１抵抗体）
２８Ｃ 感圧ゲージ抵抗（第２抵抗体） 10-force sensor 22 board (base member)
22A Insertion hole (hole)
24 Pressure receiving member 24A First pressure receiving part 24B Second pressure receiving part 24C Connection part 24D Insertion hole (hole)
26 Strain gauge (first resistor)
28C resistance temperature gauge resistance (second resistance)

Claims (3)

Ｚ軸方向の一方側に面が向けられた基部材と、
前記基部材に対してＺ軸方向の一方側に配置されていると共に前記基部材とＺ軸方向に対向して配置された第１受圧部と、前記第１受圧部に対してＺ軸方向の一方側に配置された第２受圧部と、前記第１受圧部と前記第２受圧部とをＺ軸方向につなぐ接続部と、を有する受圧部材と、
前記接続部に設けられ、前記接続部が変形されることで抵抗値が変化する第１抵抗体と、
前記基部材と前記第１受圧部との間に配置され、前記基部材と前記第１受圧部との間で圧縮されることで抵抗値が変化する第２抵抗体と、
を備えた力センサ。 A base member whose surface is directed to one side in the Z-axis direction,
A first pressure receiving portion arranged on one side in the Z-axis direction with respect to the base member and arranged facing the base member in the Z-axis direction, and a Z-axis direction with respect to the first pressure receiving portion. A pressure receiving member having a second pressure receiving portion arranged on one side and a connecting portion connecting the first pressure receiving portion and the second pressure receiving portion in the Z-axis direction.
A first resistor provided in the connection portion and whose resistance value changes when the connection portion is deformed.
A second resistor that is arranged between the base member and the first pressure receiving portion and whose resistance value changes by being compressed between the base member and the first pressure receiving portion.
Force sensor with. 前記基部材及び前記受圧部材には、Ｚ軸方向に貫通する孔が形成されている請求項１に記載の力センサ。 The force sensor according to claim 1, wherein a hole penetrating in the Z-axis direction is formed in the base member and the pressure receiving member. 前記第１抵抗体及び前記第２抵抗体は、Ｚ軸方向のまわりの周方向の４か所に等間隔に配置されている請求項１又は請求項２に記載の力センサ。
The force sensor according to claim 1 or 2, wherein the first resistor and the second resistor are arranged at four locations in the circumferential direction around the Z-axis direction at equal intervals.

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