JP3931104B2 - Triaxial load measuring sensor - Google Patents

Description

【００２８】
上記ΔＸ，ΔＹを用いて、下記(数２)式からＸ，Ｙ方向のずれ力ＳＸ，ＳＹをそれぞれ算出する。
【００２９】
【数２】

【００３０】
そして、上記(数２)式の結果を用いて、下記(数３)式からずれ力Ｓとその方向θを算出する。
【００３１】
【数３】

【００３２】
さらに、下記(数４)式からＺ方向の圧力Ｐ、すなわち永久磁石７に対して垂直な向きに作用する圧力を算出する。
【００３３】
【数４】

【００３４】
以上のようにして、ベッドに寝た患者に作用する荷重をＸ，Ｙ方向のずれ力ＸＳ，ＹＳ、ずれ力Ｓ、その方向θ、圧力Ｐに分解して求めることができる。
【００３５】
上記第１の実施の形態の場合、荷重の受容体であるゲル製パッド６として、円錐台形状のものを用いた。ゲル製パッド６をこのような円錐台形状に構成した場合、パッドベース４に対するゲル下面の接触面積が大きくなり、ずれ方向への負荷作用時にゲルの捲れが生じることがない。また、ゲルの下面が最初からパッドベース４に全面接触しているため、ゲル圧縮後の吸い付きが発生するようなこともなく、さらに、ずれ方向の変形量の設定が容易であると共に、荷重解放後の復帰性が極めて高い。
【００３６】
なお、上記実施の形態では、パッド６としてゲルを用いたが、ゲルに限られるものではなく、例えばゴムなど、荷重に応じて変形自在な弾性体であれば使用可能である。
【００３７】
また、上記実施の形態では、ゲル製のパッド６を中に挟んで、４個のホール素子３_１〜３_４を下側に、永久磁石７を上側にして対向配置した場合の例を示したが、これとは逆に、４個のホール素子３_１〜３_４を上側に、永久磁石７を下側にして対向配置してもよいものである。要は、ホール素子３_１〜３_４と永久磁石７の相対的な位置関係が荷重に応じて変化すればよい。
【００３８】
さらに、ゲル製パッド６の形状も、上述した円錐台形状のものに限らず、下記図６〜図８に示すような形状のものも用いることができる。
【００３９】
図６にパッド６の第２の形状例を示す。
このパッド６は、円板状になるゲル１９をゴム製カップ１８で囲み、このゴム製カップ１８に入った円板状の弾性体１９の上面に永久磁石７を載せ、永久磁石７の周面をゴム製カップ１８に接着すると共に、該ゴム製カップ１８をパッドベース４の天面に固着したものである。
【００４０】
このような形状のパッド６を用いた場合、モノコック構造とすることができるので、パッド自体を小さくできると共に、その価格も抑えることができ、量産にも適したものとなる。また、Ｚ軸方向の荷重に対しても、外側へ向かって膨張するゲル１９がゴム製カップ１８を押してその円筒部を外側へ変形させるので、Ｚ方向の荷重に対しても変形可能である。また、ゴム製カップ１８の円筒部のモノコック効果を利用して、ゲル１９のずれ方向の変位量を効果的に抑えることができる。
【００４１】
図７にパッド６の第３の形状例を示す。
このパッド６は、円板状をした第１のゲル１９_１の周囲をこれよりもヤング率の高い第２のゲル１９_２でドーナツ状に囲み、この内外二重構造になるゲル１９_１,１９_２の上面に永久磁石７を接着固定したものである。
【００４２】
このような形状のパッド６を用いた場合、第１のゲル１９_１の周囲をこれよりもヤング率の高い第２のゲル１９_２でドーナツ状に囲んでいるため、内側に位置する第１のゲル１９_１のずれ方向の変位量を外側の第２のゲル１９_２よって効果的に抑制できる。また、Ｚ軸方向の荷重に対しては、圧縮により横方向に膨張した第１のゲル１９_１がその外周に配置した第２のゲル１９_２を外側に向かって膨らませるので、第１のゲル１９_１が持つヤング率を維持することができる。この形状のパッド６の場合も、モノコック構造とすることができるので、パッド自体を小さくできると共に、その価格も抑えることができ、量産にも適したものとなる。
【００４３】
図８にパッド６の第４の形状例を示す。
このパッド６は、パッドベース４の凹状皿部５の深さを深くし、この凹状皿部５の中央位置に、該凹状皿部５よりも径が小さく、かつ、凹状皿部５の深さと同じ高さからなる円板状のゲル２０を接着固定し、このゲル２０の上面と凹状皿部５の全体を覆うように、ゴム製シート２１を所定のテンションをかけた状態で覆い、該ゴム製シート２１をゲル２０の天面と凹状皿部５の周縁部に接着固定し、このゴム製シート２１の上面中央部に永久磁石７を固着したものである。
【００４４】
このような形状のパッド６を用いた場合、Ｚ軸方向への圧縮時には、ゲル２０の持つヤング率をそのまま生かした弾性を発現させることができると共に、ずれ方向はゴム製シート２１の引っ張り応力により、同一荷重負荷時の変形量をずれ方向の全域において同じに維持することができる。このため、垂直方向、ずれ方向の荷重負担を明確に分けることができ、またずれ方向の変形量の設定が容易となる。この形状のパッド６の場合も、量産が比較的簡単である。
【００４５】
さらに、上述した第１の実施の形態では、４個のホール素子を用いてセンサを構成したが、ホール素子は４個に限られるものではなく、例えば図９に示すように、３個のホール素子３_１〜３_３を用い、この３個のホール素子３_１〜３_３を三角形状に配置してもよいし、あるいは図１０に示すように、５個のホール素子３_１〜３_５を用い、１個のホール素子３_５を座標軸の原点に配置すると共に、４個のホール素子３_１〜３_４を四角形のコーナー部に配置した構成としてもよい。
【００４６】
図１１に本発明に係る三軸荷重計測センサの第２の実施の形態を示す。
この第２の実施の形態は、静電容量方式によって構成した場合の例を示すものである。なお、前記第１の実施の形態と同一もしくは同等の部分には同一の符号を付し、その説明は省略する。
【００４７】
この第２の実施の形態は、図示するように、前記第１の実施の形態におけるホール素子３_１〜３_４と永久磁石７に代えて、４個の小電極１３_１〜１３_４と１個のグランド電極１７を用いたものである。
【００４８】
このようにグランド電極１７に対して小電極１３_１〜１３_４を対向配置した場合、各小電極とグランド電極間にそれぞれ静電容量が生じる。この静電容量Ｃは、次の式で表される。
Ｃ＝ε_０・ε_ｒ・Ｓ／ｄ
ただし、ε_０：真空誘電率
ε_ｒ：比誘電率
Ｓ ：グランド電極と小電極との重なり面積
ｄ ：グランド電極と小電極間の距離
【００４９】
上式から明らかなように、グランド電極１７と小電極１３_１〜１３_４間の距離ｄが小さくなれば、それに反比例して静電容量Ｃが大きくなり、また、グランド電極１７と小電極１３_１〜１３_４との重なり面積Ｓが大きくなれば、それに比例して静電容量Ｃが大きくなる。従って、この場合も、前記第１の実施の形態と同様にして、４個の小電極１３_１〜１３_４の静電容量の変化から、ずれ力Ｓ、ずれの方向θ、圧力Ｐを算出することができる。
【００５０】
なお、この第２の実施の形態の場合においても、図示とは逆に、４個の小電極１３_１〜１３_４を上側に、グランド電極１７を下側にして対向配置してもよいし、さらに、図示した円錐台形状のゲル製パッド６に代えて、前述した図６〜図８に示した形状のパッドを用いてもよいものである。
【００５１】
また、上記実施の形態では、４個の小電極１３_１〜１３_４を用いてセンサを構成したが、小電極は４個に限られるものではなく、例えば図１２に示すように、５個の小電極１３_１〜１３_５を用い、１個の小電極１３_１を原点に配置すると共に、その周りに４個の小電極１３_２〜１３_５を四角形に配置した構成としてもよい。
【００５２】
【発明の効果】
以上説明したように、本発明によれば、荷重受容体としてのパッドを最も効果的な形状となるように工夫したので、作用する荷重に対するパッドの追従性が極めて優れたものとなり、作用する荷重を作用面に垂直な圧力成分と平行なずれ力成分に正確に分解して計測することができるようになる。
【図面の簡単な説明】
【図１】 第１の実施の形態に係る三軸荷重計測センサを示すもので、（ａ）は平面図、（ｂ）は（ａ）中のＩ−Ｉ線断面図である。
【図２】 プリント配線基板の形状を示すもので、（ａ）は平面図、（ｂ）は側面図である。
【図３】 パッドベースの形状を示すもので、（ａ）は平面図、（ｂ）は背面図、（ｃ）は中央縦断面図ある。
【図４】 パッドとマグネットの形状を示すもので、（ａ）は平面図、（ｂ）は（ａ）中のII−II線断面図である。
【図５】 荷重の計測方法の説明図であって、（ａ）はホール素子と永久磁石の配置関係図、（ｂ）はずれ力のベクトル図である。
【図６】 パッドの第２の形状例を示す図である。
【図７】 パッドの第３の形状例を示す図である。
【図８】 パッドの第４の形状例を示す図である。
【図９】 ホール素子の他の配置例を示す図である。
【図１０】 ホール素子のさらに他の配置例を示す図である。
【図１１】 第２の実施の形態に係る三軸荷重計測センサを示すもので、（ａ）は平面図、（ｂ）は（ａ）中のIII−III線断面図である。
【図１２】 小電極の他の配置例を示す図である。
【符号の説明】
１ プリント配線基板
２ 電極
３_１〜３_４ ホール素子
４ パッドベース
５ 凹状皿部
６ ゲル製パッド
７ 永久磁石
８ ホール素子格納室
９ 突起
１０ 位置合わせ用穴
１１ フラットケーブル
１２ パッケージシート
１３_１〜１３_４ 小電極
１７ グランド電極
１８ ゴム製カップ
１９、１９_１,１９_２ ゲル
２０ ゲル
２１ ゴム製シート[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a triaxial load measurement sensor that measures a load acting on a body of a patient lying on a bed, for example, by decomposing the load into a pressure component perpendicular to the acting surface and a displacement force parallel to the acting surface.
[0002]
[Prior art]
It is known that bedridden sick people, elderly caregivers, and the like generate sores, so-called bed slips, mainly in portions that are in contact with the bed for a long time. To prevent this sore, it is necessary to move the body as much as possible to eliminate blood circulation problems so that the same part is not pressed for a long time. For this reason, care measures such as changing the direction of the patient's body sleeping every fixed time or changing the tilt angle of the bed have been taken.
[0003]
In recent years, research on the shape and structure of the bed and the air mat laid on the bed has been advanced to prevent the occurrence of wounds, and the applied load is dispersed as much as possible to reduce the pressure on the human body as much as possible. The idea to make it small is made.
[0004]
[Problems to be solved by the invention]
By the way, it is generally said that the occurrence of sores is proportional to the product of the pressure acting on the human body and the time of action. To prevent sores, how much pressure actually acts when sleeping on a bed. It is important to know what to do. Conventionally, various contact pressure sensors have been developed and used in order to measure such pressure, but all detect the load acting on the human body as a pressure perpendicular to the human body surface. It was.
[0005]
However, according to recent research, not only the magnitude of the so-called contact pressure acting in the direction perpendicular to the human body surface, but also the so-called displacement force acting in the direction parallel to the human body surface is important for the occurrence of sores. It has been pointed out that this is a serious factor. For this reason, it is not sufficient to detect the load acting like a conventional contact pressure sensor as only the pressure in the direction perpendicular to the human body surface, and the applied load is applied to the pressure in the direction perpendicular to the human body surface and the human body surface. It has become necessary to accurately measure by decomposing into parallel displacement forces.
[0006]
The present invention has been made on the basis of the above-mentioned demand, and is a triaxial load measuring sensor for measuring an acting load by decomposing it into a pressure component perpendicular to the acting surface and a displacement force parallel to the acting surface, The present invention provides a triaxial load measurement sensor that is devised in the shape of an elastic body that is a load receiving body, has excellent followability to the load, and can accurately measure the displacement force and pressure.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention employs the following means.
That is, the triaxial load measuring sensor according to claim 1 has a permanent magnet (or a plurality of hall elements) fixed on the upper surface of the elastic body fixed on the pad base, and a plurality of sensors on the lower side of the pad base. The Hall elements (or permanent magnets) are opposed to each other, the upper surface side of the permanent magnet (or a plurality of Hall elements) located on the upper side is used as a load acting surface, and the output voltage of the plurality of Hall elements is used. A triaxial load measuring sensor for measuring an acting load by decomposing it into a displacement force in a direction parallel to the acting surface and a pressure in a direction perpendicular to the acting surface, and using a disk-like elastic body as the elastic body The disk-shaped elastic body is surrounded by a rubber cup, and a permanent magnet (or a plurality of hall elements) is placed on the upper surface of the disk-shaped elastic body contained in the rubber cup and fixed to the rubber cup. In addition, the rubber cup is One in which was fixed to the base of the top surface.
[0008]
The triaxial load measuring sensor according to claim 2 has a permanent magnet (or a plurality of hall elements) fixed on the upper surface of the elastic body fixed on the pad base, and a plurality of sensors on the lower side of the pad base. The Hall elements (or permanent magnets) are opposed to each other, the upper surface side of the permanent magnet (or a plurality of Hall elements) located on the upper side is used as a load acting surface, and the output voltage of the plurality of Hall elements is used. A triaxial load measuring sensor for measuring an acting load by decomposing it into a displacement force in a direction parallel to the acting surface and a pressure in a direction perpendicular to the acting surface, wherein the elastic body is a disc-shaped first sensor Using an elastic body surrounded by a second elastic body having a higher Young's modulus than that of the elastic body in a donut shape, a permanent magnet (or a plurality of Hall elements) is formed on the upper surface of the elastic body having an internal / external double structure. The inner and outer double structure. It is obtained by fixing the elastic member to the top surface of the pad base.
[0009]
The triaxial load measuring sensor according to claim 3 has a permanent magnet (or a plurality of hall elements) fixed on the upper surface of the elastic body fixed on the pad base, and a plurality of sensors on the lower side of the pad base. The Hall elements (or permanent magnets) are opposed to each other, the upper surface side of the permanent magnet (or a plurality of Hall elements) located on the upper side is used as a load acting surface, and the output voltage of the plurality of Hall elements is used. A triaxial load measuring sensor for measuring an acting load by breaking it into a displacement force in a direction parallel to the acting surface and a pressure in a direction perpendicular to the acting surface, which is formed on the top surface of the pad base as the elastic body. A disc-shaped elastic body having the same height as the depth of the concave dish portion and having a width smaller than that of the concave dish portion is used, and the disk-shaped elastic body having a smaller width is placed in the concave dish portion of the top surface of the pad base. It adheres to the center of the concave dish and The entire surface is covered with a rubber sheet with a predetermined tension, and the rubber sheet with the tension is adhesively fixed to the top surface portion of the disk-shaped elastic body and the peripheral edge portion of the concave dish portion, and the adhesive fixing is performed. A permanent magnet (or a plurality of Hall elements) is fixed to the center of the upper surface of the rubber sheet.
[0010]
In the triaxial load measuring sensor according to claim 4, a ground electrode (or a plurality of small electrodes) is fixed to the upper surface of the elastic body fixed on the pad base, and a plurality of sensors are provided below the pad base. The small electrodes (or ground electrodes) are arranged opposite to each other, and the upper surface of the ground electrode (or a plurality of small electrodes) is used as the load acting surface, and works by using the capacitance of each small electrode. A triaxial load measuring sensor for measuring a load by decomposing the force into a displacement force in a direction parallel to the working surface and a pressure in a direction perpendicular to the working surface, wherein the elastic body uses a disk-like elastic body, A disk-shaped elastic body is surrounded by a rubber cup, and a ground electrode (or a plurality of small electrodes) is placed on the upper surface of the disk-shaped elastic body contained in the rubber cup and fixed to the rubber cup. , the rubber cup top surface of the pad base It is obtained by wearing.
[0011]
In the triaxial load measuring sensor according to claim 5, a ground electrode (or a plurality of small electrodes) is fixed to the upper surface of the elastic body fixed on the pad base, and a plurality of sensors are provided below the pad base. The small electrodes (or ground electrodes) are arranged opposite to each other, and the upper surface of the ground electrode (or a plurality of small electrodes) is used as the load acting surface, and works by using the capacitance of each small electrode. A triaxial load measurement sensor for measuring a load by decomposing into a displacement force in a direction parallel to the working surface and a pressure in a direction perpendicular to the working surface, wherein the elastic body is a disc-shaped first elastic body A ground electrode (or a plurality of small electrodes) is fixed to the upper surface of the elastic body having a double structure inside and outside using an elastic body surrounded by a donut shape with a second elastic body having a higher Young's modulus. In addition, the elastic body having the inner and outer double structure is filtered. Those fixed to the top surface of the Dobesu.
[0012]
In the triaxial load measuring sensor according to claim 6, a ground electrode (or a plurality of small electrodes) is fixed to the upper surface of the elastic body fixed on the pad base, and a plurality of sensors are provided below the pad base. The small electrodes (or ground electrodes) are arranged opposite to each other, and the upper surface of the ground electrode (or a plurality of small electrodes) is used as the load acting surface, and works by using the capacitance of each small electrode. A triaxial load measuring sensor for measuring a load by decomposing it into a displacement force in a direction parallel to the working surface and a pressure in a direction perpendicular to the working surface, the concave shape formed on the top surface portion of the pad base as the elastic body A disk-shaped elastic body having the same height as the depth of the dish portion and having a width smaller than that of the concave dish portion is used, and the disk-shaped elastic body having a smaller width is placed in the center of the concave dish portion of the pad base top surface. And the entire top surface of the concave dish The rubber sheet covered with the tension is adhered and fixed to the top surface portion of the disk-like elastic body and the peripheral edge portion of the concave dish portion, and the adhesive-fixed rubber sheet A ground electrode (or a plurality of small electrodes) is fixed to the center of the upper surface.
[0013]
Moreover, triaxial load measuring sensor according to claim 7, in the three-axis load measuring sensor according to the claims 1 to 6, is characterized in that using a gel as an elastic body.
[0014]
In the case of the triaxial load measuring sensor configured as described above, the followability of the elastic body with respect to the load becomes extremely excellent, and the applied load can be calculated by accurately decomposing the applied load into displacement force and pressure.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 4 show a first embodiment of a triaxial load measuring sensor according to the present invention.
This first embodiment shows an example of a case where it is configured by a magnetic detection method, FIG. 1 is a diagram showing the overall shape of a triaxial load measurement sensor, FIG. 2 is a diagram showing the shape of a printed wiring board, FIG. 3 is a diagram showing the shape of the pad base, and FIG. 4 is a diagram showing the shapes of the pad and the magnet.
[0016]
In the figure, reference numeral 1 denotes a printed wiring board serving as a base, and the planar shape of the printed wiring board is a so-called front-rear circular ring shape. Are formed, and four Hall elements 3 _{1 to} 3 ₄ which are magnetic sensing elements are formed in a circular portion. Are fixed on the X-axis and the Y-axis, two at a distance from the origin O.
[0017]
Wherein the four upper Hall elements 3 ₁ to 3 _4, rigid plastic pad base 4 to be substantially the same shape as the printed circuit board 1 is fixed and arranged so as to cover the entire hall elements 3 ₁ to 3 ₄ Has been. Then, a frustoconical pad 6 made of an elastically deformable gel is fitted and fixed to the concave dish portion 5 on the top surface of the pad base. four Hall elements 3 ₁ to 3 disc-shaped permanent magnet 7 consisting of size to cover the entire ₄ is fixed arranged to face the Hall element 3 ₁ to 3 _4. The permanent magnet 7 is magnetized in a direction perpendicular to the plate surface, and is configured such that the upper and lower surfaces of the disk-shaped permanent magnet 7 are N and S magnetic pole surfaces.
[0018]
Note that four Hall element storage chambers 8 are formed in a cross shape on the back side of the pad base 4, and four Hall elements 3 _{1 to} 3 ₄ are formed in the four Hall element storage chambers 8. by accommodating each, together with closer distances Hall element ₃ 1 to 3 ₄ and the permanent magnet 7, to protect the Hall element ₃ 1 to 3 ₄ from external forces.
[0019]
Two small projections 9 are formed at the front and rear positions of the four hall element storage chambers 8, and the two projections 9 are formed in alignment holes formed at corresponding positions on the printed wiring board 1. 10, the pad base 4 and the printed wiring board 1 are aligned.
[0020]
On the other hand, an electric wire such as a flat cable 11 is connected to the electrode 2 of the printed wiring board 1, and power is supplied to the printed wiring board 1 through the flat cable 11 and each of the hall elements 3 ₁ to 3. 3 is configured to take out the _fourth output.
[0021]
The printed wiring board 1 in which the Hall elements 3 _{1 to} 3 ₄ , the pad base 4, the gel pad 6, the permanent magnet 7 and the flat cable 11 are assembled together is a package made of, for example, a transparent vinyl sheet. Wrapped with a sheet 12, the back surface portion of the printed circuit board 1 and the upper surface portion of the permanent magnet 7 are bonded to the package sheet 12 by heat fusion or adhesive, and the side edges 13 of the package sheet 12 are sealed by heat welding or the like. By doing so, injuries and the like due to direct contact of the sensor with human skin and the like are prevented, and waterproofing and moisture prevention are achieved.
[0022]
Next, a load measuring method using the triaxial load measuring sensor will be described with reference to FIG. 5A is a diagram showing the positional relationship between the Hall elements 3 _{1 to} 3 ₄ and the permanent magnets 7, and FIG. 5B is a vector diagram of the displacement force, and the meaning of each symbol in the diagram is as follows: Street.
[0023]
XP: Output value of the Hall element 3 ₁ arranged on the + side on the X axis XN: Output value of the Hall element 3 ₂ arranged on the − side on the X axis YP: Hall element 3 arranged on the + side on the Y axis ₃ of the output value YN: Y on axis - the output value of the Hall element _{3 4} arranged on the side S: displacement force theta: the direction of the shift force S XS: X-direction component of the displacement force S YS: Y direction deviation force S Component P: pressure in the Z direction (vertically downward)
At the time of measurement, a triaxial load measuring sensor is attached to a region to be measured, for example, a waist, back, sacrum, etc. of a patient sleeping on a bed using a double-sided adhesive tape or the like. When a patient attached with a triaxial load measurement sensor lies on the bed, a load acts on the upper surface of the permanent magnet 7 as a load application surface according to the tilt of the bed, the state of the air mat or the futon, the posture at that time, and the like. When a load is applied, the gel pad 6 is deformed according to the magnitude and direction of the load, and outputs XP to YN are generated from the _four Hall elements 3 ₁ to 34 according to the deformation state at that time.
[0025]
The outputs XP to YN are taken out through the electrode 2 and the flat cable 11 and sent to an arithmetic processing unit constituted by a computer or the like. By performing the following arithmetic processing, the displacement force in the X and Y directions is obtained. XS, YS, displacement force S, direction θ, and pressure P are calculated.
[0026]
First, the output values XP, XN, YP, YN of a pair of Hall elements 3 ₁ , 3 ₂ , 3 ₃ , 3 ₄ corresponding on the same axis are subtracted, and the difference value ΔX, Find ΔY.
[0027]
[Expression 1]

[0028]
Using the above ΔX and ΔY, displacement forces SX and SY in the X and Y directions are calculated from the following (Equation 2), respectively.
[0029]
[Expression 2]

[0030]
Then, the displacement force S and its direction θ are calculated from the following equation (3) using the result of the above equation (2).
[0031]
[Equation 3]

[0032]
Further, the pressure P in the Z direction, that is, the pressure acting in the direction perpendicular to the permanent magnet 7 is calculated from the following equation (4).
[0033]
[Expression 4]

[0034]
As described above, the load acting on the patient sleeping on the bed can be determined by decomposing the displacement forces XS, YS, the displacement force S, the direction θ, and the pressure P in the X and Y directions.
[0035]
In the case of the first embodiment, a frustoconical shape is used as the gel pad 6 which is a load receptor. When the gel pad 6 is configured in such a truncated cone shape, the contact area of the lower surface of the gel with respect to the pad base 4 is increased, and the gel does not sag when a load is applied in the displacement direction. In addition, since the lower surface of the gel is in full contact with the pad base 4 from the beginning, there is no sticking after the gel compression, and it is easy to set the amount of deformation in the displacement direction, and the load The returnability after release is extremely high.
[0036]
In the above embodiment, the gel is used as the pad 6, but the pad 6 is not limited to the gel, and any elastic body that can be deformed according to a load, such as rubber, can be used.
[0037]
In the above embodiment, sandwiched in the gel pad made of 6, the four Hall elements 3 ₁ to 3 ₄ to the lower, an example of a case where opposed to the permanent magnets 7 on the upper side However, conversely, the four Hall elements 3 _{1 to} 3 ₄ may be arranged on the upper side and the permanent magnet 7 on the lower side to be opposed to each other. In short, it may be changed according to the load relative positional relationship between the Hall element 3 ₁ to 3 ₄ and the permanent magnet 7.
[0038]
Furthermore, the shape of the gel pad 6 is not limited to the shape of the truncated cone described above, and the shape shown in FIGS.
[0039]
FIG. 6 shows a second shape example of the pad 6.
The pad 6 surrounds a disk-shaped gel 19 with a rubber cup 18, and a permanent magnet 7 is placed on the upper surface of the disk-shaped elastic body 19 contained in the rubber cup 18. Is adhered to the rubber cup 18 and the rubber cup 18 is fixed to the top surface of the pad base 4.
[0040]
When the pad 6 having such a shape is used, a monocoque structure can be obtained, so that the pad itself can be made small and the price thereof can be suppressed, which is suitable for mass production. Further, the gel 19 that expands outward also pushes the rubber cup 18 to deform the cylindrical portion outward even with respect to the load in the Z-axis direction, and therefore can be deformed even with respect to the load in the Z-direction. Moreover, the amount of displacement of the gel 19 in the shifting direction can be effectively suppressed by utilizing the monocoque effect of the cylindrical portion of the rubber cup 18.
[0041]
FIG. 7 shows a third shape example of the pad 6.
The pad 6, first around the gel 19 ₁ which surrounds a donut shape in the second gel 19 ₂ high Young's modulus than the gel 19 _1, 19 to become the inner and outer double structure in which the disc-shaped _The permanent magnet 7 is bonded and fixed to the upper surface of No. ₂ .
[0042]
When using the pad 6 having such a shape, since the surrounding in a donut shape in the first gel 19 ₁ of the second gel 19 high Young's modulus than this ambient _2, first located inside the displacement amount of the displacement direction of the gel 19 ₁ can second gel 19 ₂ Therefore effectively suppressed outside. Also, for the load in the Z-axis direction, the first gel 19 ₁ inflated laterally to inflate the second gel 19 ₂ disposed on the outer periphery thereof toward the outside by the compression, a first gel The Young's modulus of 19 ₁ can be maintained. Also in the case of the pad 6 having this shape, since it can be a monocoque structure, the pad itself can be made small, the price thereof can be suppressed, and it is suitable for mass production.
[0043]
FIG. 8 shows a fourth shape example of the pad 6.
The pad 6 increases the depth of the concave dish portion 5 of the pad base 4, has a diameter smaller than that of the concave dish portion 5 at the central position of the concave dish portion 5, and the depth of the concave dish portion 5. A disc-shaped gel 20 having the same height is bonded and fixed, and the rubber sheet 21 is covered with a predetermined tension so as to cover the upper surface of the gel 20 and the entire concave dish portion 5, and the rubber The sheet 21 is bonded and fixed to the top surface of the gel 20 and the peripheral edge of the concave dish portion 5, and the permanent magnet 7 is fixed to the center of the upper surface of the rubber sheet 21.
[0044]
When the pad 6 having such a shape is used, at the time of compression in the Z-axis direction, elasticity that makes use of the Young's modulus of the gel 20 can be expressed as it is, and the displacement direction is caused by the tensile stress of the rubber sheet 21. The deformation amount when the same load is applied can be kept the same in the entire region in the shift direction. For this reason, the load burden in the vertical direction and the displacement direction can be clearly divided, and the deformation amount in the displacement direction can be easily set. Also in the case of this shape of the pad 6, mass production is relatively easy.
[0045]
Furthermore, in the first embodiment described above, the sensor is configured using four Hall elements. However, the number of Hall elements is not limited to four. For example, as shown in FIG. using an element ₃ 1 to 3 _3, to the three Hall elements ₃ 1 to 3 ₃ may be arranged in a triangular shape, or as shown in FIG. 10, the five hall elements ₃ 1 to 3 ₅ used, in conjunction with placing the one Hall element ₃₅ to the origin of the coordinate axes may be four Hall elements 3 ₁ to 3 ₄ as configuration disposed in a corner portion of the rectangle.
[0046]
FIG. 11 shows a second embodiment of the triaxial load measuring sensor according to the present invention.
This 2nd Embodiment shows the example at the time of comprising by an electrostatic capacitance system. In addition, the same code | symbol is attached | subjected to the part which is the same as that of the said 1st Embodiment, or equivalent, and the description is abbreviate | omitted.
[0047]
The second embodiment, as shown, in place of the Hall element ₃ 1 to 3 ₄ and the permanent magnet 7 in the first embodiment, one and four small electrodes _131-134 The ground electrode 17 is used.
[0048]
Thus if a small electrode _131-134 and opposed with respect to the ground electrode 17, respectively capacitance is generated between the small electrodes and the ground electrode. This capacitance C is expressed by the following equation.
C = ε ₀ · ε _r · S / d
Where ε _{0 is the} vacuum dielectric constant
ε _r : relative permittivity
S: Overlap area of ground electrode and small electrode
d: Distance between ground electrode and small electrode
As apparent from the above equation, if the ground electrode 17 decreases the distance d between the small electrodes _131-134, inversely proportional to it the capacitance C becomes larger, also the ground electrode 17 small electrodes 13 ₁ the larger the overlap area S between to 13 _4, the electrostatic capacitance C becomes larger in proportion thereto. Accordingly, in this case as well, as in the first embodiment, the displacement force S, the displacement direction θ, and the pressure P are calculated from the change in capacitance of the _four small electrodes 13 _{1 to} 134. be able to.
[0050]
Incidentally, the second even when the embodiment, contrary to the illustration, four small electrodes _131-134 in the upper, to the ground electrode 17 may be disposed opposite to the lower side, Further, instead of the illustrated frustoconical gel pad 6, the pads having the shapes shown in FIGS. 6 to 8 may be used.
[0051]
In the above embodiment, the sensor is configured using the _four small electrodes 13 _{1 to} 13 _4. However, the number of the small electrodes is not limited to four. For example, as illustrated in FIG. The small electrodes 13 _{1 to} 13 ₅ may be used, and one small electrode 13 ₁ may be arranged at the origin, and four small electrodes 13 _{2 to} 13 ₅ may be arranged in a square around the small electrode 13 ₁ .
[0052]
【The invention's effect】
As described above, according to the present invention, the pad as the load receptor is devised so as to have the most effective shape, so that the followability of the pad with respect to the acting load becomes extremely excellent, and the acting load Can be accurately decomposed and measured into a displacement component parallel to the pressure component perpendicular to the working surface.
[Brief description of the drawings]
FIGS. 1A and 1B show a triaxial load measurement sensor according to a first embodiment, in which FIG. 1A is a plan view and FIG. 1B is a cross-sectional view taken along line II in FIG.
FIGS. 2A and 2B show the shape of a printed wiring board, where FIG. 2A is a plan view and FIG. 2B is a side view.
3A and 3B show the shape of a pad base, wherein FIG. 3A is a plan view, FIG. 3B is a rear view, and FIG. 3C is a central longitudinal sectional view.
4A and 4B show the shapes of a pad and a magnet, where FIG. 4A is a plan view, and FIG. 4B is a cross-sectional view taken along line II-II in FIG.
FIGS. 5A and 5B are explanatory diagrams of a load measuring method, in which FIG. 5A is an arrangement relation diagram of Hall elements and permanent magnets, and FIG. 5B is a vector diagram of a displacement force.
FIG. 6 is a diagram showing a second shape example of the pad.
FIG. 7 is a diagram illustrating a third shape example of a pad.
FIG. 8 is a diagram illustrating a fourth shape example of a pad.
FIG. 9 is a diagram illustrating another arrangement example of the Hall elements.
FIG. 10 is a diagram showing still another arrangement example of the Hall elements.
11A and 11B show a triaxial load measuring sensor according to a second embodiment, wherein FIG. 11A is a plan view and FIG. 11B is a cross-sectional view taken along line III-III in FIG.
FIG. 12 is a diagram showing another arrangement example of small electrodes.
[Explanation of symbols]
1 printed wiring board 2 electrodes 3 ₁ to 3 ₄ Hall element 4 pad base 5 concave dish 6 gel manufactured pad 7 holes for the permanent magnets 8 a Hall element storage chamber 9 projections 10 aligned 11 flat cable 12 package sheet _131-134 Small electrode 17 Ground electrode 18 Rubber cup 19, 19 ₁ , 19 ₂ Gel 20 Gel 21 Rubber sheet

Claims (7)

A permanent magnet (or a plurality of Hall elements) is fixed to the upper surface of the elastic body fixed on the pad base, and a plurality of Hall elements (or permanent magnets) are arranged opposite to each other on the lower side of the pad base. The upper surface side of the permanent magnet (or a plurality of hall elements) positioned on the side is the load acting surface, and the output voltage of the plurality of hall elements is used as the displacement force in the direction parallel to the acting surface. A triaxial load measuring sensor that decomposes and measures pressure in a direction perpendicular to the working surface ,
A disk-shaped elastic body is used as the elastic body, the disk-shaped elastic body is surrounded by a rubber cup, and a permanent magnet (or a plurality of magnets) is formed on the upper surface of the disk-shaped elastic body contained in the rubber cup. A three-axis load measuring sensor characterized in that it is fixed to a rubber cup by mounting a plurality of Hall elements) and the rubber cup is fixed to the top surface of the pad base . A permanent magnet (or a plurality of Hall elements) is fixed to the upper surface of the elastic body fixed on the pad base, and a plurality of Hall elements (or permanent magnets) are arranged opposite to each other on the lower side of the pad base. The upper surface side of the permanent magnet (or a plurality of hall elements) positioned on the side is the load acting surface, and the output voltage of the plurality of hall elements is used as the displacement force in the direction parallel to the acting surface. A triaxial load measuring sensor that decomposes and measures pressure in a direction perpendicular to the working surface,
As the elastic body, an elastic body in which the periphery of the first elastic body having a disk shape is surrounded by a second elastic body having a higher Young's modulus in a donut shape is used, and this elastic body has an internal / external double structure. A triaxial load measuring sensor , wherein a permanent magnet (or a plurality of Hall elements) is fixed to the upper surface of the pad base, and an elastic body having an inner / outer double structure is fixed to the top surface of the pad base . A permanent magnet (or a plurality of Hall elements) is fixed to the upper surface of the elastic body fixed on the pad base, and a plurality of Hall elements (or permanent magnets) are arranged opposite to each other on the lower side of the pad base. The upper surface side of the permanent magnet (or a plurality of hall elements) positioned on the side is the load acting surface, and the output voltage of the plurality of hall elements is used as the displacement force in the direction parallel to the acting surface. A triaxial load measuring sensor that decomposes and measures pressure in a direction perpendicular to the working surface,
As the elastic body, a disk-shaped elastic body having the same height as the depth of the concave dish portion formed on the top surface portion of the pad base and having a smaller width than the concave dish portion is used. The elastic body is fixed to the central portion of the concave plate portion on the top surface of the pad base, and the entire upper surface of the concave plate portion is covered with a rubber sheet with a predetermined tension, and the rubber sheet with the tension is applied. The disk-shaped elastic body is bonded and fixed to the top surface portion and the peripheral edge portion of the concave dish portion, and a permanent magnet (or a plurality of hall elements) is fixed to the center of the upper surface of the bonded and fixed rubber sheet. A triaxial load measuring sensor. A ground electrode (or a plurality of small electrodes) is fixed on the upper surface of the elastic body fixed on the pad base, and a plurality of small electrodes (or ground electrodes) are arranged opposite to each other on the lower side of the pad base. The upper surface of the ground electrode (or a plurality of small electrodes) located on the side is used as a load acting surface, and using the capacitance of each small electrode, the acting load is shifted in the direction parallel to the acting surface and the acting surface. A triaxial load measuring sensor that decomposes and measures pressure in a direction perpendicular to
A disc-shaped elastic body is used as the elastic body, the disc-shaped elastic body is surrounded by a rubber cup, and a ground electrode (or a plurality of electrodes) is formed on the upper surface of the disk-shaped elastic body contained in the rubber cup. A triaxial load measuring sensor characterized in that the small cup is mounted and fixed to a rubber cup, and the rubber cup is fixed to the top surface of the pad base . A ground electrode (or a plurality of small electrodes) is fixed on the upper surface of the elastic body fixed on the pad base, and a plurality of small electrodes (or ground electrodes) are arranged opposite to each other on the lower side of the pad base. The upper surface of the ground electrode (or a plurality of small electrodes) located on the side is used as a load acting surface, and using the capacitance of each small electrode, the acting load is shifted in the direction parallel to the acting surface and the acting surface. A triaxial load measuring sensor that decomposes and measures pressure in a direction perpendicular to
As the elastic body, an elastic body in which the periphery of the first elastic body having a disk shape is surrounded by a second elastic body having a higher Young's modulus in a donut shape is used, and this elastic body has an internal / external double structure. A triaxial load measuring sensor , wherein a ground electrode (or a plurality of small electrodes) is fixed to the upper surface of the pad base, and an elastic body having an inner / outer double structure is fixed to the top surface of the pad base . A ground electrode (or a plurality of small electrodes) is fixed on the upper surface of the elastic body fixed on the pad base, and a plurality of small electrodes (or ground electrodes) are arranged opposite to each other on the lower side of the pad base. The upper surface of the ground electrode (or a plurality of small electrodes) located on the side is used as a load acting surface, and using the capacitance of each small electrode, the acting load is shifted in the direction parallel to the acting surface and the acting surface. A triaxial load measuring sensor that decomposes and measures pressure in a direction perpendicular to
As the elastic body, a disk-shaped elastic body having the same height as the depth of the concave dish portion formed on the top surface portion of the pad base and having a smaller width than the concave dish portion is used. The elastic body is fixed to the central portion of the concave plate portion on the top surface of the pad base, and the entire upper surface of the concave plate portion is covered with a rubber sheet with a predetermined tension, and the rubber sheet with the tension is applied. The disk-like elastic body is bonded and fixed to the top surface portion and the peripheral edge portion of the concave dish portion, and a ground electrode (or a plurality of small electrodes) is fixed to the center of the upper surface of the bonded and fixed rubber sheet. A triaxial load measuring sensor.   The triaxial load measuring sensor according to claim 1, wherein gel is used as the elastic body.

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