JPS6334414B2 - - Google Patents
Info
- Publication number
- JPS6334414B2 JPS6334414B2 JP57001540A JP154082A JPS6334414B2 JP S6334414 B2 JPS6334414 B2 JP S6334414B2 JP 57001540 A JP57001540 A JP 57001540A JP 154082 A JP154082 A JP 154082A JP S6334414 B2 JPS6334414 B2 JP S6334414B2
- Authority
- JP
- Japan
- Prior art keywords
- weight
- point
- strain gauge
- resistance
- load cell
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 229910052751 metal Inorganic materials 0.000 claims description 16
- 239000002184 metal Substances 0.000 claims description 16
- 229910001120 nichrome Inorganic materials 0.000 claims description 15
- 229910045601 alloy Inorganic materials 0.000 claims description 14
- 239000000956 alloy Substances 0.000 claims description 14
- VNNRSPGTAMTISX-UHFFFAOYSA-N chromium nickel Chemical compound [Cr].[Ni] VNNRSPGTAMTISX-UHFFFAOYSA-N 0.000 claims description 10
- 239000011248 coating agent Substances 0.000 claims description 10
- 238000000576 coating method Methods 0.000 claims description 10
- 239000007769 metal material Substances 0.000 claims description 9
- 239000011347 resin Substances 0.000 claims description 9
- 229920005989 resin Polymers 0.000 claims description 9
- 229910052804 chromium Inorganic materials 0.000 claims description 8
- 238000010586 diagram Methods 0.000 claims description 8
- 229910052759 nickel Inorganic materials 0.000 claims description 8
- 229910052710 silicon Inorganic materials 0.000 claims description 7
- 239000000203 mixture Substances 0.000 description 10
- 229910019819 Cr—Si Inorganic materials 0.000 description 7
- 238000004544 sputter deposition Methods 0.000 description 7
- 239000010409 thin film Substances 0.000 description 7
- 238000005259 measurement Methods 0.000 description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- 238000005530 etching Methods 0.000 description 3
- 239000010408 film Substances 0.000 description 3
- 238000009413 insulation Methods 0.000 description 3
- 238000001552 radio frequency sputter deposition Methods 0.000 description 3
- 239000004642 Polyimide Substances 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000010931 gold Substances 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229920001721 polyimide Polymers 0.000 description 2
- 235000012239 silicon dioxide Nutrition 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000007733 ion plating Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000001259 photo etching Methods 0.000 description 1
- 239000011253 protective coating Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000007261 regionalization Effects 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 238000010301 surface-oxidation reaction Methods 0.000 description 1
- 238000001771 vacuum deposition Methods 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Classifications
-
- 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
- G01L1/2287—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 constructional details of the strain gauges
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Force In General (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Description
【発明の詳細な説明】
本発明は荷重を測定する荷重検出器等に使用さ
れるロードセルに関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a load cell used in a load detector or the like for measuring load.
金属箔抵抗体パターンを接着した絶縁フイルム
を、ビーム体上に接着し、この後リード線で結線
して構成される公知のロードセルに比較して、製
造工数が少なく容易かつ安価に製造できるととも
に、高精度の測定が可能なロードセルを提供する
ために、ビーム体に直接設けた樹脂製絶縁被膜上
に、金属材料を蒸着又はスパツタリング等により
被着させて、この金属層により必要な回路パター
ンを直接形成して構成されるロードセルが、本発
明者等により提案され、既に出願済みである。 Compared to known load cells that are constructed by bonding an insulating film with a metal foil resistor pattern bonded onto a beam body and then connecting it with lead wires, the load cell can be manufactured easily and inexpensively with fewer manufacturing steps. In order to provide a load cell capable of high-precision measurement, a metal material is deposited by vapor deposition or sputtering on a resin insulating coating provided directly on the beam body, and the necessary circuit pattern is directly formed using this metal layer. The present inventors have proposed a load cell constructed by forming the above, and an application has already been filed.
この種のロードセルは、絶縁被膜が樹脂製であ
ることにより、同被膜を二酸化珪素製とした場合
に比較して歩留りが高い利点がある。なお、二酸
化珪素製絶縁被膜の形成条件はビーム体表面の仕
上げ条件に依存され、ピンホールやキズ等によつ
て絶縁不良が生じる可能性が高く、よつて歩留り
が悪い。また、この種ロードセルの回路パターン
のうちストレンゲージ抵抗体パターンは、一般的
なニクロム（Ni80重量％、Cr20重量％）で形成
されるが、このニクロムの抵抗温度係数は通常数
百PPm／℃である。ところで、ロードセルでは
正確な測定を行うために、ブリツジバランスの零
点ドリフトの発生をおさえる必要がある。しか
し、上記のように抵抗温度係数が大きいと、通電
時のジユール熱および環境温度により、抵抗変化
を生じて零点が動いてしまうから、環境温度が大
きく違う用途および環境温度変化が小さくても高
精度の測定を要求される用途の使用には問題があ
つた。さらに、ニクロム（Ni80重量％、Cr20重
量％）製のストレンゲージ抵抗体パターンからな
るブリツジは抵抗の経時変化が大きく、この意味
でも零点の安定性を確保しづらしことが分つた。
なお、これは上記組成の抵抗体パターンを備える
ロードセルを、60℃の雰囲気中に置いて抵抗変化
を測定した実験により確認されたもので、第９図
のグラフ中点線で示される。また、ニクロムをビ
ーム体に設けた絶縁被膜上に直接形成する際に、
真空容器内の酸素分圧をコントロールしながら行
つて、ニクロムの酸化物を形成させ、その酸化物
の抵抗の負の温度係数を利用して、ストレンゲー
ジ抵抗体パターンの抵抗温度係数を零に近づける
操作が、本発明者により試みられたが、コントロ
ールが非常に難しく、したがつて再現性がなくバ
ラツキ易いという結果がでて、実用的でないこと
が分つた。 This type of load cell has an advantage in that the yield is higher because the insulation coating is made of resin, compared to a case where the insulation coating is made of silicon dioxide. Note that the conditions for forming the silicon dioxide insulating film depend on the finishing conditions of the surface of the beam body, and there is a high possibility that insulation defects will occur due to pinholes, scratches, etc., resulting in poor yield. In addition, the strain gauge resistor pattern in the circuit pattern of this type of load cell is made of general nichrome (Ni80% by weight, Cr20% by weight), but the temperature coefficient of resistance of this nichrome is usually several hundred ppm/℃. be. By the way, in order to perform accurate measurements with a load cell, it is necessary to suppress the occurrence of bridge balance zero point drift. However, if the temperature coefficient of resistance is large as mentioned above, the resistance will change due to the Joule heat and the environmental temperature when the current is applied, and the zero point will move. There were problems when using it in applications that required precision measurements. Furthermore, the bridge, which consists of a strain gauge resistor pattern made of nichrome (Ni80% by weight, Cr20% by weight), has a large change in resistance over time, and in this sense, it has been found that it is difficult to ensure stability at the zero point.
This was confirmed by an experiment in which a load cell having a resistor pattern having the above composition was placed in an atmosphere at 60° C. and resistance changes were measured, and this is shown by the dotted line in the graph of FIG. 9. In addition, when forming nichrome directly on the insulating coating provided on the beam body,
This is done while controlling the oxygen partial pressure in the vacuum chamber to form nichrome oxide, and by utilizing the negative temperature coefficient of resistance of that oxide, the resistance temperature coefficient of the strain gauge resistor pattern approaches zero. Although this procedure was attempted by the inventor, it was found to be impractical as it was very difficult to control and the results were therefore non-reproducible and variable.
本発明は上記の事情にもとづいて提案されたも
ので、その目的はストレンゲージ抵抗体パターン
の抵抗温度係数を略零にできてブリツジ回路の零
点ドリフトを極小とでき高精度の測定が可能で、
しかも製造にも特に困難をきたさないロードセル
を提供しようとするものである。 The present invention was proposed based on the above circumstances, and its purpose is to make the resistance temperature coefficient of the strain gauge resistor pattern approximately zero, minimize the zero point drift of the bridge circuit, and enable highly accurate measurement.
Furthermore, the present invention aims to provide a load cell that does not pose any particular difficulty in manufacturing.
以下、本発明を図面に示す実施例にもとづいて
説明する。 The present invention will be described below based on embodiments shown in the drawings.
まず、第１図及び第２図に、完成品としてのロ
ードセルを示す。ビーム体１は、例えばステンレ
ス鋼（SUS630）高力アルミニウム合金（A2218）
等の金属材料を切削加工して形成されている。こ
のビーム体１は、一端部に設けられた取付孔２
Ａ，２Ｂに取付ボルト３Ａ，３Ｂを通して任意の
固定部４に取付けられるようになつている。ま
た、ビーム体１の中間部分は薄肉の起歪部５とな
つており、ビーム体１の他端側より起歪部５の下
方位置まで作用片６を延出させ、この作用片６に
設けた透孔７に、例えば吊下金具８を取付けて、
測定すべき荷重を矢印Ｗの如く作用させるように
している。このビーム体１の上面にはポリイミ
ド、エポキシ、アミドイミド、エポキシ変成ポリ
イミド等の耐熱絶縁性樹脂よりなる絶縁被膜１０
が被着されている。そして絶縁被膜１０上には、
第３図に示すようなブリツジ回路を構成する第１
〜第４のストレンゲージ抵抗体パターン１１Ａ〜
１１Ｄ及びリードパターン１２………が直接設け
られている。第１〜第４のストレンゲージ抵抗体
パターン１１Ａ〜１１Ｄは、その各抵抗値RA〜
RDがいずれも同一となるように、かつ二等分割
されている。これら第１〜第４のストレンゲージ
抵抗体パターン１１Ａ〜１１Ｄを形成する金属材
料は、NiCrを主成分としSiを含む合金であつて、
Cr成分が50重量％以下、Ni成分が50重量％以上、
Si成分が23重量％以下のNi−Cr−Si系合金であ
り、本実施例はNi成分が71重量％、Cr成分が18
重量％、Si成分が11重量％の場合である。勿論、
Ni−Cr−Si系合金はNi、Cr、Siの各成分だけで
構成されるものではなく、Ni−Cr−Si系合金と
しての本質的性能に影響を及ぼさない程度の少量
の他の元素が添加されていることは言うまでもな
い。そして、前記各分割抵抗体１１A1，１１A2
………１１D1，１１D2は、いずれも起歪部５の
両端部に存在する、歪量の相等しい最大歪領域５
Ａ，５Ｂに対向して設けられている。なお、一方
の最大歪領域５Ａには、作用片６に荷重Ｗを作用
させたとき最大伸び歪が生じ、他方の最大歪領域
５Ｂには最大収縮歪が生ずるようになつている。
そして第１、第２のストレンゲージ抵抗体パター
ン１１Ａ，１１Ｂは最大伸び歪領域５Ａに、また
第３、第４のストレンゲージ抵抗体パターン１１
Ｃ，１１Ｄは最大収縮歪領域５Ｂに、それぞれ対
向して設けられている。そして、最大伸び歪領域
５Ａにおいては、第１のストレンゲージ抵抗体パ
ターン１１Ａを構成する両分割抵抗体１１A1，
１１A2で、第２のストレンゲージ抵抗体パター
ン１１Ｂを構成する分割抵抗体１１B1，１１B2
を挾むような配置になつている。また、最大収縮
歪領域５Ｂにおいては、第３のストレンゲージ抵
抗体パターン１１Ｃを構成する分割抵抗体１１
C1，１１C2と第３のストレンゲージ抵抗体パタ
ーン１１Ｄを構成する分割抵抗体１１D1，１１
D2とが隣接して配置されている。なお、各分割
抵抗体１１A1，１１A2，………１１D1，１１D2
は、第４図に示すようにジグザグ状をなして構成
されており、その両端にリードパターン１２が接
続するようになつている。また、前記分割抵抗体
１１A1，１１A2，………１１D1，１１D2間を接
続するリードパターン１２………は、互に交差し
ないことは勿論であるが、前記２つの領域５Ａ，
５Ｂのいずれを通過することもないように設けら
れている。リードパターン１２………は、前記
Ni−Cr−Si系合金の金属層およびこの上に直接
積層されたAu、Cr等の金属層により形成されて
いる。そして、リードパターン１２………の一部
（分割抵抗体１１A1，１１C2間、１１B1，１１
D2間、１１C1，１１B2間及び１１D1，１１A2間
を接続するリードパターンの各中央部）をそれぞ
れ端子部Ａ，Ｂ，Ｃ，Ｄとし、外部リード線１３
………を介して端子部Ａ，Ｂ間に入力電圧V1を
印加し、端子部Ｃ，Ｄ間に発生する出力電圧V0
を測定することにより荷重Ｗの大きさを検出する
ような構成となつている。また、前記ストレンゲ
ージ抵抗体パターン１１Ａ〜１１Ｄ及びリードパ
ターン１２………は、耐熱絶縁性樹脂よりなる保
護被膜９でオーバーコーテングされている。 First, FIGS. 1 and 2 show a load cell as a completed product. The beam body 1 is made of, for example, stainless steel (SUS630) or high-strength aluminum alloy (A2218).
It is formed by cutting metal materials such as. This beam body 1 has a mounting hole 2 provided at one end.
Mounting bolts 3A and 3B are passed through A and 2B so that it can be attached to any fixed part 4. Further, the middle portion of the beam body 1 is a thin strain-generating portion 5, and an action piece 6 is extended from the other end side of the beam body 1 to a position below the strain-generating portion 5. For example, attach a hanging fitting 8 to the through hole 7,
The load to be measured is applied as shown by arrow W. The upper surface of the beam body 1 is coated with an insulating coating 10 made of a heat-resistant insulating resin such as polyimide, epoxy, amide-imide, epoxy-modified polyimide, etc.
is covered. And on the insulating coating 10,
The first circuit that constitutes a bridge circuit as shown in Figure 3.
~Fourth strain gauge resistor pattern 11A~
11D and lead pattern 12 are directly provided. The first to fourth strain gauge resistor patterns 11A to 11D each have a resistance value of RA to
It is divided into two halves so that both RDs are the same. The metal material forming these first to fourth strain gauge resistor patterns 11A to 11D is an alloy containing NiCr as a main component and containing Si,
Cr component is 50% by weight or less, Ni component is 50% by weight or more,
It is a Ni-Cr-Si alloy with a Si content of 23% by weight or less, and in this example, the Ni content is 71% by weight and the Cr content is 18% by weight.
This is a case where the Si component is 11% by weight. Of course,
Ni-Cr-Si alloys are not only composed of Ni, Cr, and Si, but also contain small amounts of other elements that do not affect the essential performance of the Ni-Cr-Si alloy. Needless to say, it is added. And each of the divided resistors 11A 1 and 11A 2
...... 11D 1 and 11D 2 are maximum strain regions 5 with the same amount of strain existing at both ends of the strain generating section 5.
It is provided facing A and 5B. In addition, when the load W is applied to the action piece 6, the maximum elongation strain occurs in one maximum strain area 5A, and the maximum contraction strain occurs in the other maximum strain area 5B.
The first and second strain gauge resistor patterns 11A and 11B are located in the maximum elongation strain region 5A, and the third and fourth strain gauge resistor patterns 11
C and 11D are provided facing each other in the maximum shrinkage strain region 5B. In the maximum elongation strain region 5A, both divided resistors 11A 1 , which constitute the first strain gauge resistor pattern 11A,
11A 2 , divided resistors 11B 1 , 11B 2 forming the second strain gauge resistor pattern 11B
It is arranged so that it is sandwiched between the two. Furthermore, in the maximum shrinkage strain region 5B, the divided resistor 11 constituting the third strain gauge resistor pattern 11C
C 1 , 11 C 2 and divided resistor 11D 1 , 11 forming the third strain gauge resistor pattern 11D
D 2 are placed adjacent to each other. In addition, each divided resistor 11A 1 , 11A 2 , ...... 11D 1 , 11D 2
As shown in FIG. 4, it has a zigzag shape, and lead patterns 12 are connected to both ends thereof. Furthermore, it goes without saying that the lead patterns 12 connecting between the divided resistors 11A 1 , 11A 2 , 11D 1 , 11D 2 do not intersect with each other, but the two regions 5A,
5B so as not to pass through any of them. Lead pattern 12... is the above-mentioned
It is formed of a metal layer of Ni-Cr-Si alloy and a metal layer of Au, Cr, etc. directly laminated thereon. Then, a part of the lead pattern 12 (between the divided resistors 11A 1 and 11C 2 , between 11B 1 and 11
The center portions of the lead patterns connecting between D 2 , 11C 1 and 11B 2 , and between 11D 1 and 11A 2 are terminal portions A, B, C, and D, respectively, and the external lead wires 13
An input voltage V 1 is applied between terminals A and B via ......, and an output voltage V 0 is generated between terminals C and D.
The structure is such that the magnitude of the load W can be detected by measuring . Further, the strain gauge resistor patterns 11A to 11D and the lead patterns 12 are overcoated with a protective coating 9 made of a heat-resistant insulating resin.
次に、以上に述べたロードセルの製造方法を第
５図により説明する。 Next, a method for manufacturing the load cell described above will be explained with reference to FIG.
まず、第５図Ａのような、切削加工により得ら
れたビーム体１の上面を脱脂洗浄し、その洗浄さ
れた面上に、粘度1000cp程度に調整されたワニ
ス状のポリイミド樹脂液を滴下する。そしてビー
ム体１をスピンナにより1600rpm程度の速度で回
転することによつて、ビーム体１の上面に耐熱絶
縁性樹脂を均一に塗布する。その後、100℃で約
１時間加熱して溶剤を乾燥し、続けて250℃で約
５時間加熱すると、樹脂が硬化してビーム体１の
上面に厚さ約４〜5μｍの耐熱絶縁性樹脂被膜１
０が形成される。次に、上記絶縁被膜１０上に、
ストレンゲージ抵抗体となる金属材料すなわち
Ni−Cr−Si系合金（例えばNi71％、Cr18％、
Si11％）をスパツタリングにより被着して厚さ約
500Åの金属層１１′を形成し、更にその上に、リ
ードパターンとなる金属材料（例えば金）をスパ
ツタリングにより被着して、厚さ約1.5μｍの金属
層１２′を積層形成する。 First, the upper surface of the beam body 1 obtained by cutting as shown in FIG. . Then, by rotating the beam body 1 with a spinner at a speed of about 1600 rpm, the heat-resistant insulating resin is uniformly applied to the upper surface of the beam body 1. After that, the solvent is dried by heating at 100°C for about 1 hour, and then heated at 250°C for about 5 hours, the resin hardens and a heat-resistant insulating resin coating with a thickness of about 4 to 5 μm is formed on the upper surface of the beam body 1. 1
0 is formed. Next, on the insulating coating 10,
Metal material that becomes the strain gauge resistor, i.e.
Ni-Cr-Si alloy (e.g. Ni71%, Cr18%,
11% Si) was deposited by sputtering to a thickness of approx.
A metal layer 11' having a thickness of 500 Å is formed, and a metal material (for example, gold) that will become a lead pattern is deposited thereon by sputtering to form a metal layer 12' having a thickness of approximately 1.5 μm.
次に、同図Ｂのように、金属層１２′及び１
１′に対して順次、それぞれの金属に適したエツ
チング液を用いてフオトエツチングを行ない、ス
トレンゲージ抵抗体パターンとなる部分及びリー
ドパターンとなる部分のみを残して他を除去し、
所定のパターンを現出させる。 Next, as shown in FIG.
1' is sequentially photo-etched using an etching solution suitable for each metal, leaving only the part that will become the strain gauge resistor pattern and the part that will become the lead pattern, and removing the others.
Make a predetermined pattern appear.
次に、同図Ｃのように、ストレンゲージ抵抗体
パターンとなる部分に積層された金属層１２′を
フオトエツチングにより除去し、前記分割抵抗体
１１A1，１１A2，………１１D1，１１D2を現出
させる。ここで、残りの部分は各分割抵抗体間を
接続するリードパターン１２………となる。 Next, as shown in Figure C, the metal layer 12' laminated on the portion that will become the strain gauge resistor pattern is removed by photo-etching, and the divided resistors 11A 1 , 11A 2 , . . . 11D 1 , 11D are removed. Make 2 appear. Here, the remaining portion becomes a lead pattern 12 that connects each divided resistor.
更に、同図Ｄのように、ストレンゲージ抵抗体
パターン及びリードパターンの上に再び耐熱絶縁
性樹脂よりなる保護被膜９をオーバーコンテング
する。 Furthermore, as shown in FIG. 3D, a protective film 9 made of a heat-resistant insulating resin is again overcontained over the strain gauge resistor pattern and lead pattern.
最後に、同図Ｅのように、保護被膜９の一部
（分割抵抗体１１A1，１１C2間、１１B1，１１
D2間、１１C1，１１B2間及び１１D1，１１A2間
を接続するリードパターン１２………の各中央部
を覆う部分）をそれぞれエツチングにより除去し
て、それらの部分におけるリードパターン１２…
……の各露出部を端子部Ａ，Ｂ，Ｃ，Ｄとし、各
端子部に、例えばアルミニウム、金等よりなる外
部リード線１３………をボンデイングする。以上
で第１図及び第２図に示すロードセルが完成され
る。 Finally, as shown in FIG .
The lead patterns 12 connecting between D 2 , 11C 1 and 11B 2 , and between 11D 1 and 11A 2 (the portions covering the central portions of the lead patterns 12 ) are removed by etching, and the lead patterns 12 in those portions are removed by etching.
The exposed portions of . With the above steps, the load cell shown in FIGS. 1 and 2 is completed.
以上の構造のロードセルによれば以下の理由に
より高精度の測定を行うことができる。すなわ
ち、本発明者は、NiCr合金をベースにしてこれ
にSiを添加すると、特定の組成領域において抵抗
温度係数が極少となることを以下の実験により見
出した。Ni80重量％、Cr20重量％の合金をベー
スにしてSiを添加した薄膜抵抗体を得るために、
NiCrターゲツトにSiを加えてRFスパツタを行つ
た。その結果、第６図に示したようにSiが５、
13、20重量％と増加するにつれて薄膜抵抗体（厚
さ400〜500Å）の抵抗温度係数は＋80、０、−
80ppm／℃と次第に減少することが分つた。一
方、Siを含まないNiCr合金においても、NiとCr
の比率を変えると抵抗温度係数が変わることが分
つた。すなわち、第７図に示したようにNiCrタ
ーゲツトのCr成分比を20、40、60重量％と変え
たとき、RFスパツタにより得られた薄膜抵抗体
の抵抗温度係数は＋130、＋70、0ppm／℃と減少
することが分つた。そして、第７図において、
Niの増量につれて増える抵抗温度係数を、第６
図のデータを考慮してSiを適量添加することによ
り零にすることを試みた。即ち、Ｎ、Cr、Siの
組成比を０点（Ni40、Cr60、Si0）、Ａ点（Ni50、
Cr45、Si5）、Ｂ点（Ni60、Cr32、Si8）、Ｃ点
（Ni71、Cr18、Si11）、Ｄ点（Ni83、Cr0、Si17）
（但しカツコ内数字は重量％、以下同じ）の５点
を選んでターゲツトを作り、以下の条件でRFス
パツタを行つた。 According to the load cell having the above structure, highly accurate measurement can be performed for the following reasons. That is, the present inventor found through the following experiment that when Si is added to a NiCr alloy as a base, the temperature coefficient of resistance becomes extremely small in a specific composition range. In order to obtain a thin film resistor based on an alloy of 80% Ni and 20% Cr and added with Si,
RF sputtering was performed by adding Si to a NiCr target. As a result, as shown in Figure 6, Si was 5,
13. As the weight percent increases to 20%, the temperature coefficient of resistance of a thin film resistor (thickness 400 to 500 Å) increases to +80, 0, -
It was found that the concentration gradually decreased to 80ppm/℃. On the other hand, even in NiCr alloys that do not contain Si, Ni and Cr
It was found that the temperature coefficient of resistance changes when the ratio of That is, as shown in Figure 7, when the Cr component ratio of the NiCr target is changed to 20, 40, and 60% by weight, the temperature coefficient of resistance of the thin film resistor obtained by RF sputtering is +130, +70, and 0ppm/℃. It was found that this decreases. And in Figure 7,
The temperature coefficient of resistance, which increases as the amount of Ni increases, is determined by the sixth
Considering the data shown in the figure, an attempt was made to reduce it to zero by adding an appropriate amount of Si. That is, the composition ratios of N, Cr, and Si are set at point 0 (Ni40, Cr60, Si0) and point A (Ni50,
Cr45, Si5), point B (Ni60, Cr32, Si8), point C (Ni71, Cr18, Si11), point D (Ni83, Cr0, Si17)
(However, the numbers in brackets are weight %, the same applies below) to create targets and perform RF sputtering under the following conditions.
到達真空度 ２×10-6Torr
Ar分圧 ９×10-3Torr
電源 RF1KV
基板 ガラス基板
基板温度 常温
得られた、厚さ400〜500Åの薄膜抵抗体の抵抗
温度係数は、Ｏ、Ａ、Ｂ、Ｃ、Ｄ点共ほゞ零であ
つた。この結果は、第８図のNi、Cr、Siの成分
比を示す三角図表で、Ｏ、Ａ、Ｂ、Ｃ、Ｄ点を通
る直線上で抵抗温度係数が零の薄膜抵抗体を得ら
れることを示している。ただし、Ｏ点の場合は
Crが多いために、真空装置の残留酸素の影響が
大きくなり再現性が悪いことが分つた。即ち、
Crが多くなるにつれて、真空装置、ベルジヤー
の大きさ、内部治具の量や材質、排気速度や排気
時間、基板温度等の装置依存性が大きくなるとと
もに、ターゲツト自体も表面酸化が大きくなり、
機械的にも脆くなる等の問題が生じる。このよう
な結果に拘らず実際には多少の組成のずれ、不純
物の含有等がおこるが、実用的にはスパツタリン
グ条件をコントロールする等により、使用できる
範囲は多少広がることが分つた。即ち、第８図の
B′点（Ni65、Cr32、Si5）、C′点（Ni70、Cr10、
Si20）においても、B′点はわずかに酸素分圧が高
い雰囲気内で、またC′点はわずかに酸素分圧が低
い雰囲気内でスパツタリングした場合、共に抵抗
温度係数がほゞ零のものが得られた。これに対
し、B″点（Ni70、Cr30、Si0）、C″点（Ni60、
Cr18、Si22）のターゲツト組成では、スパツタ
リング条件をコントロールしても抵抗温度係数が
零のものは得られず、第６図、第７図から明らか
な通り、B″点は＋100ppm／℃、C″点は−
100ppm／℃となる。Ultimate vacuum 2×10 -6 Torr Ar partial pressure 9×10 -3 Torr Power supply RF1KV Substrate Glass substrate Substrate temperature Room temperature The temperature coefficients of resistance of the obtained thin film resistor with a thickness of 400 to 500 Å are O, A, B , C, and D points were almost zero. This result shows that a thin film resistor with a temperature coefficient of resistance of zero can be obtained on a straight line passing through points O, A, B, C, and D in the triangular diagram shown in Figure 8, which shows the component ratios of Ni, Cr, and Si. It shows. However, in the case of O point
It was found that due to the large amount of Cr, the influence of residual oxygen in the vacuum equipment became large, resulting in poor reproducibility. That is,
As the amount of Cr increases, the dependence on the vacuum equipment, the size of the bell jar, the amount and material of internal jigs, the pumping speed and time, the substrate temperature, etc. increases, and the surface oxidation of the target itself increases.
Problems such as mechanical brittleness also occur. Despite these results, in practice, some deviation in composition and inclusion of impurities occur, but in practice it has been found that by controlling sputtering conditions, etc., the usable range can be somewhat expanded. That is, in Figure 8
Point B′ (Ni65, Cr32, Si5), point C′ (Ni70, Cr10,
In Si20), when sputtering is performed at point B' in an atmosphere with a slightly high oxygen partial pressure, and at point C' in an atmosphere with a slightly low oxygen partial pressure, both have a temperature coefficient of resistance of almost zero. Obtained. On the other hand, point B″ (Ni70, Cr30, Si0), point C″ (Ni60,
With the target composition of Cr18, Si22), even if the sputtering conditions are controlled, it is not possible to obtain a zero resistance temperature coefficient, and as is clear from Figures 6 and 7, point B'' is +100 ppm/℃, C'' The point is -
100ppm/℃.
以上の結果を総合すると、第８図の三角図表に
おいて、実用上好ましい組成範囲としてＷ点
（Ni50、Cr50、Si0）、Ｘ点（Ni90、Cr0、Si10）、
Ｙ点（Ni77、Cr0、Si23）、Ｚ点（Ni50、Cr40、
Si10）を結ぶ四角形で囲まれた範囲が求まる。 Combining the above results, in the triangular diagram in Figure 8, the practically preferred composition ranges are W point (Ni50, Cr50, Si0), X point (Ni90, Cr0, Si10),
Y point (Ni77, Cr0, Si23), Z point (Ni50, Cr40,
Find the range surrounded by the rectangle connecting Si10).
ちなみに、本実施例に示した第８図中Ｃ点の組
成のNi−Cr−Si系合金からなるストレンゲージ
抵抗体パターン１１Ａ〜１１Ｄ）を備えて構成し
たロードセルでは、零点ドリフトが約1μV／Ｖ未
満という高性能のものが実現できた。 Incidentally, in the load cell constructed with the strain gauge resistor patterns 11A to 11D made of Ni-Cr-Si alloy having the composition shown at point C in FIG. 8 shown in this example, the zero point drift is approximately 1 μV/V. We were able to achieve a high performance product with less than
なお、上記Ni−Cr−Si系合金でNiを50重量％
以上、Crを50重量％以下に限定しているのは、
Crが余り多くなると既述のように装置依存性が
大きくなり、かつ機械的にも脆くなる問題がある
ためで、一方、Siを23重量％以下に限定している
のは、Siを余り多くすると抵抗温度係数が負方向
に大きくなり過ぎて実用上好ましくないためであ
る。 In addition, in the above Ni-Cr-Si alloy, Ni is 50% by weight.
As mentioned above, the reason why Cr is limited to 50% by weight or less is that
If the Cr content is too large, as mentioned above, there will be a problem of increased device dependence and mechanical brittleness.On the other hand, the reason why Si is limited to 23% by weight or less is that if the Si content is too large, This is because the temperature coefficient of resistance becomes too large in the negative direction, which is not desirable in practice.
また、ストレンゲージ抵抗体パターン１１Ａ〜
１１Ｄを形成する金属材料は、NiCrベースにSi
を添加することで、全体に占めるCrの割合いを
低下させ得るために、経時的変化を小さくしてブ
リツジの零点の安定性を高めることができる。こ
れは第９図のグラフ中実線で示され、点線で示し
たNiCr製のものに比較して明らかである。 In addition, strain gauge resistor patterns 11A~
The metal material forming 11D is Si based on NiCr.
By adding Cr, the proportion of Cr in the whole can be lowered, so changes over time can be reduced and the stability of the zero point of the bridge can be increased. This is shown by the solid line in the graph of FIG. 9, and is clear compared to the NiCr product shown by the dotted line.
なお、本発明は、ビーム体のヤング率の温度特
性による出力電圧の温度依存性を補償するための
スパン抵抗体パターンを設けたロードセルにも実
施できる。この場合、スパン抵抗体パターンとな
る金属材料にはTiやNi等が用いられ、この金属
層はスパツタリングにより、ストレンゲージ抵抗
体パターンの金属層に被着されて設けられ、勿論
その上にリードパターンとなる金属層が被着され
るとともに、バターン形成の際にはTi又はNi等
に合うエツチヤントが使用されることは言うまで
もない。また、各金属層の被着形成は、真空蒸着
又はイオンプレーテングによりなしてもよい。 Note that the present invention can also be implemented in a load cell provided with a span resistor pattern for compensating for the temperature dependence of the output voltage due to the temperature characteristics of the Young's modulus of the beam body. In this case, Ti, Ni, etc. are used as the metal material for the span resistor pattern, and this metal layer is deposited on the metal layer of the strain gauge resistor pattern by sputtering. Needless to say, a metal layer is deposited and an etchant suitable for Ti or Ni is used during pattern formation. Further, each metal layer may be formed by vacuum deposition or ion plating.
以上説明した本発明は、上記特許請求の範囲に
記載の構成を要旨とする。したがつて、ストレン
ゲージ抵抗体パターンの抵抗温度係数をほゞ零と
できるとともに、経時的変化も小さくできるの
で、ブリツジ回路の零点ドリフトが極小となり、
高精度の荷重測定を実現できる。しかも、ストレ
ンゲージ抵抗体パターンの抵抗温度係数を零に近
ずけるのに、ストレンゲージ抵抗体パターンを形
成する金属材料の組成によつて実現し従来のよう
に格別困難な酸素分圧のコントロール等が必要不
可欠とされないので、製造にも困難性がないもの
である。 The gist of the present invention described above is the structure described in the claims. Therefore, the temperature coefficient of resistance of the strain gauge resistor pattern can be made almost zero, and the change over time can also be made small, so the zero point drift of the bridge circuit can be minimized.
Highly accurate load measurement can be achieved. Moreover, in order to bring the temperature coefficient of resistance of the strain gauge resistor pattern close to zero, it is possible to control the oxygen partial pressure, which is extremely difficult in the past, due to the composition of the metal material forming the strain gauge resistor pattern. Since it is not considered indispensable, there is no difficulty in manufacturing it.
図面は本発明の一実施例を示すもので、第１図
はロードセルの斜視図、第２図は同ロードセルの
断面図、第３図は同ロードセルの回路図、第４図
は部分拡大図、第５図Ａ〜Ｅは製造方法を工程順
に示す図、第６図はSi添加によるNiCr合金薄膜
抵抗体の抵抗温度係数変化を示す図、第７図は
NiCr合金薄膜抵抗体のCr比による抵抗温度係数
変化を示す図、第８図はストレンゲージ抵抗体パ
ターンの好ましい組成範囲を説明するためのNi、
Cr、Siの３成分組成図、第９図は相異なる組成
のストレンゲージ抵抗体パターンで形成したブリ
ツジ回路の抵抗経時変化を示す図である。
１……ビーム体、１０……絶縁被膜、１１Ａ〜
１１Ｄ……ストレンゲージ抵抗体パターン、１
１′……金属層。
The drawings show one embodiment of the present invention, and FIG. 1 is a perspective view of a load cell, FIG. 2 is a sectional view of the load cell, FIG. 3 is a circuit diagram of the load cell, and FIG. 4 is a partially enlarged view. Figures 5A to 5E are diagrams showing the manufacturing method in the order of steps, Figure 6 is a diagram showing the change in resistance temperature coefficient of NiCr alloy thin film resistor due to Si addition, and Figure 7 is
Figure 8 shows the change in temperature coefficient of resistance depending on the Cr ratio of a NiCr alloy thin film resistor.
The three-component composition diagram of Cr and Si, FIG. 9, is a diagram showing the change in resistance over time of a bridge circuit formed with strain gauge resistor patterns having different compositions. 1...Beam body, 10...Insulating coating, 11A~
11D...Strain gauge resistor pattern, 1
1'...Metal layer.
Claims (1)
に、絶縁性樹脂よりなる絶縁被膜を直接形成し、
この被膜上に金属層を直接被着し、この金属層に
よりストレンゲージ抵抗体パターンを形成したロ
ードセルにおいて、上記金属層を形成した金属材
料は、NiCrを主成分としSiを含む合金であつて、
かつNi、Cr、Siの成分比は三角図表において、
Niが50重量％、Crが50重量％、Siが０重量％の
点Ｗと、Niが90重量％、Crが０重量％、Siが10
重量％の点Ｘと、Niが77重量％、Crが０重量％、
Siが23重量％の点Ｙと、Niが50重量％、Crが40
重量％、Siが10重量％の点Ｚで囲まれる四角形の
範囲内となるように設定したことを特徴とするロ
ードセル。1. An insulating coating made of insulating resin is directly formed on the surface of the beam body on which the load to be measured is applied,
In a load cell in which a metal layer is directly deposited on this film and a strain gauge resistor pattern is formed by this metal layer, the metal material forming the metal layer is an alloy mainly composed of NiCr and containing Si,
And the component ratios of Ni, Cr, and Si are shown in the triangular diagram,
Point W is 50% by weight of Ni, 50% by weight of Cr, and 0% by weight of Si, and 90% by weight of Ni, 0% by weight of Cr, and 10% by weight of Si.
Point X of weight%, Ni is 77% by weight, Cr is 0% by weight,
Point Y where Si is 23% by weight, Ni is 50% by weight and Cr is 40%
A load cell characterized in that weight % and Si are set within a rectangular range surrounded by a point Z of 10 weight %.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP154082A JPS58118930A (en) | 1982-01-08 | 1982-01-08 | Load cell |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP154082A JPS58118930A (en) | 1982-01-08 | 1982-01-08 | Load cell |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58118930A JPS58118930A (en) | 1983-07-15 |
| JPS6334414B2 true JPS6334414B2 (en) | 1988-07-11 |
Family
ID=11504352
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP154082A Granted JPS58118930A (en) | 1982-01-08 | 1982-01-08 | Load cell |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58118930A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3403042A1 (en) * | 1984-01-30 | 1985-08-01 | Philips Patentverwaltung Gmbh, 2000 Hamburg | THIN FILM STRETCH MEASUREMENT STRIP SYSTEM AND METHOD FOR THE PRODUCTION THEREOF |
| JPS61152905U (en) * | 1985-03-15 | 1986-09-22 | ||
| US4777826A (en) * | 1985-06-20 | 1988-10-18 | Rosemount Inc. | Twin film strain gauge system |
| JP2717812B2 (en) * | 1988-08-23 | 1998-02-25 | 株式会社イシダ | Load cell |
| JP2008309719A (en) * | 2007-06-15 | 2008-12-25 | Tanita Corp | Load cell strain body, load cell and weight measuring device using load cell strain body, and method for producing load cell strain body |
| JP2019078726A (en) | 2017-10-27 | 2019-05-23 | ミネベアミツミ株式会社 | Strain gauge and sensor module |
| JP2019174387A (en) | 2018-03-29 | 2019-10-10 | ミネベアミツミ株式会社 | Strain gauge |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4830955A (en) * | 1971-08-26 | 1973-04-23 | ||
| JPS5114358A (en) * | 1974-07-26 | 1976-02-04 | Shinko Tsushin Kogyo Kk | NETSUKASOSEITORIWAKE FUKATSUSEINO PURASUCHITSUKUHYOMENNI TENCHAKUKANONAHIZUMI GEEJITOSONO TENCHAKUHO |
-
1982
- 1982-01-08 JP JP154082A patent/JPS58118930A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS4830955A (en) * | 1971-08-26 | 1973-04-23 | ||
| JPS5114358A (en) * | 1974-07-26 | 1976-02-04 | Shinko Tsushin Kogyo Kk | NETSUKASOSEITORIWAKE FUKATSUSEINO PURASUCHITSUKUHYOMENNI TENCHAKUKANONAHIZUMI GEEJITOSONO TENCHAKUHO |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58118930A (en) | 1983-07-15 |
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