JPS62235533A - Force sensor - Google Patents

Abstract

PURPOSE:To easily obtain the magnitude of a load by measuring an inductance by applying the load to a load connecting member, producing a distortion in a sensing member, changing its permeability and accordingly changing the inductance of a detecting coil. CONSTITUTION:A rectangular sensing member 1 is fixed at both ends to an annular base material 2 and a load connecting member 3 is fixed to the central portion of the member 1. The members 1 and 3 are stuck to each other by caulking with rivets 3a. The member 1 is the sheets of the spring material made up of the ribbon 1a of an iron amorphous alloy with excellent magnetostrictive characteristics and phosphor bronze. The ribbon 1a is plated with a thin copper to both surfaces in advance and integrally adhered to spring members 1b and 1c by a polymerizable macromolecular adhesive 1d. When a load is applied to the member 3 of a force sensor, a distortion is produced in the member 1 and its permeability is changed to change the inductance 24 of detecting coils 4. Thus, by measuring the inductance 24, the magnitude of the load can be learned.

Description

[Detailed description of the invention] The present invention relates to a force sensor for measuring loads and the like.

Part of April Support Reeds - To measure the size of a load, etc., there is a conventional method of measuring its displacement using a spring, etc., and a force sensor is used to detect that displacement or strain and convert it into an electrical output. Some of these methods include those that use differential transformers, those that utilize piezoelectric characteristics, and those that utilize strain resistance change characteristics.

However, those that utilize piezoelectric characteristics are unsuitable for static measurements, and those that utilize strain resistance characteristics, although stable, have small outputs and vary in quality. Further, devices using differential transformers have the disadvantage that they are difficult to miniaturize and are expensive.

On the other hand, since an amorphous alloy material with excellent magnetostrictive properties has recently been developed, a force sensor has been proposed in which this material is used as a part of a magnetic circuit and a coil is attached to the magnetic circuit. However, such amorphous alloy materials have only been available with a thickness of 0.0i to 0.05 mm, and have fatal drawbacks such as uneven strength and brittleness. Force sensors using magnetostrictive properties had not been put into practical use.

1+t' The present invention aims to eliminate the drawbacks of the prior art, and aims to economically provide a magnetostrictive force sensor that has stable quality, can set a wide measurement load range, and is highly sensitive. This is the purpose.

1. , n , 27゛, Le In order to achieve the above object, the force sensor of the present invention includes a plate-shaped sensing member formed by laminating and bonding an amorphous alloy layer having magnetostrictive properties and an elastic metal layer, and the sensing member. a load coupling member provided at the center of the sensing member; a base material for identifying both ends of the sensing member;
and a detection coil provided surrounding the sensing member.

The sensing member used in the present invention is formed by laminating and bonding together a thin elastic metal plate such as stainless steel, brass, or phosphor bronze, and a thin plate of an amorphous alloy having iron-based magnetostrictive properties. It is. Bonding materials used for such bonding include, for example, low-temperature metal solder and polymer adhesives, and in order to strengthen the bond, the surfaces of the elastic metal plates and amorphous alloy plates are coated with appropriate pretreatment. A treatment such as copper plating may be applied.

The thickness of the elastic metal plate constituting the sensing member of the present invention is preferably selected according to the width and length of the sensing member and the magnitude of the expected load. May be adjusted. Further, the amorphous alloy thin plate is not limited to one, but a plurality of sheets may be laminated, and furthermore, elastic metal plates and amorphous alloy thin plates may be alternately laminated to constitute a laminated plate material for a sensing member.

The thus obtained laminate is cut, for example, into a rectangular shape to form a leaf spring-like sensing member. A load coupling member such as a plate having a V-shaped groove or the like for coupling the load is provided in the center of the sensing member, and is fixed by fixing means such as a rivet. In this case, the base material to be connected to the case or the like of the force sensor is identified by fixing means such as rivets.

The detection coil surrounding the sensing member is preferably installed with a slight gap maintained so as not to prevent the sensing member from deflecting due to the load, and the sensing coil is arranged in series over the entire length of the sensing member. It is particularly advantageous to accommodate them in two coils.

The cross-sectional shape of the detection coil is not particularly limited, but if the cross-sectional shape of the sensing member is a flat rectangle, the coil should also have a correspondingly flat cross-sectional shape to improve the sensitivity and compactness of the force sensor. It is preferable from the point of view of

11. Hereinafter, an example of the force sensor of the present invention will be explained based on FIGS. 1 and 2.

1 is a rectangular plate-shaped sensing member, 2 is an annular base material for identifying both ends of the sensing member 10, 3 is a load coupling member fixed to the center of the sensing member, and 4 is a detection coil. . The sensing member l and the base material 2 are fixed by bolts 2a,
Further, the sensing member 1 and the load coupling member 3 are caulked and fixed with rivets 3a. The base material 2 has two frames 21
and 22 are integrally connected by a bolt 23, and both ends of the receiving tube member l are held between the frames 21 and 22 and identified. Further, 3b is a V-shaped coupling groove for applying the load accurately to the center.

FIG. 3 is an example showing the configuration of the sensing member l in the force sensor of the present invention. 1a is a ribbon made of an iron-based amorphous alloy having excellent magnetostrictive properties, and 1b and lc are sheets of spring material made of phosphor bronze. The amorphous alloy ribbon la is pre-plated with copper to a thickness of about 2 mm on both sides, and is integrally joined to the spring material 1b and the IC using a polymeric polymer adhesive Field.

The force sensor configured in this way is coupled to a detection circuit as shown in FIG. 4, for example, but this circuit is designed so that a change in the inductance of the detection coil 4 can be extracted as an output voltage of the multivibrator circuit. It is constructed.

- When a load is applied to the load coupling member of the force sensor of the present invention, distortion occurs in the sensing member and its magnetic permeability changes, thereby changing the inductance of the detection coil. Therefore, the magnitude of the load can be determined by measuring the inductance by appropriate means.

Since the force sensor of the present invention uses a sensing member in which an amorphous alloy layer with excellent magnetostrictive properties and an elastic metal layer are laminated and bonded, it can be adjusted according to the desired load range. It is possible to easily create a sensing member having elasticity, and it is also easy to mass-produce sensing members of the same standard. Moreover, the laminated and bonded sensing member has significantly better workability and assembly workability than sheets made of amorphous alloy alone, and a force sensor with stable quality and performance can be obtained.

Furthermore, since the sensing member can be installed at a fixed position inside the detection coil, sensitivity is good and stable output can be obtained, and the installation of the force sensor has the advantage of not being affected by posture, etc. .

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view of an embodiment of the force sensor of the present invention, FIG. 2 is a vertical cross-sectional view, FIG. 3 is an explanatory diagram showing the structure of the sensing member, and FIG. 4 is a force sensor. The output coupled to′
It is a circuit diagram of an example of A position. 1 Sensing member 2 Base material 3 Load coupling member 4 Detection coil

Claims (1)

[Claims] Identifying a plate-shaped sensing member formed by laminating and bonding an amorphous alloy layer having magnetostrictive properties and an elastic metal, a load coupling member provided at the center of the sensing member, and both ends of the sensing member. A force sensor comprising a base material and a detection coil provided surrounding the sensing member.