JPS63304125A - Load measuring element - Google Patents

Abstract

PURPOSE:To obtain a load measuring element which is better in characteristics than a load measuring element formed by using a metallic strain inducing body and can make measurement even in a high temp. region or special environment by sticking strain gages to a strain inducing body formed by molding ceramics having an electrical insulating characteristic. CONSTITUTION:The ceramics such as silicon nitride, zirconium oxide or alumina having the electrical insulating characteristic is molded to form the strain inducing body 1 provided with flanges 2, 3 at the top and bottom ends of a cylindrical shape. The strain gages 4 are stuck the cylindrical outside peripheral face of the strain inducing body 1. This strain inducting body is housed into a protective cylinder 5 made of metal. The flanges 2, 3 at the top and bottom ends project slightly to above and below from the end of the protective cylinder 5 and O-rings 6 made of rubber fitted into the groove parts on the inside surface of the protective cylinder 5 come into contact with said flanges. A connector for taking the lead wires of the gages 4 is provided to the side part of the protective cylinder 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a load measuring element using a ceramic as a strain body.

[Prior Art] Conventionally, a metal body has been used as a strain-generating body used in a strain gauge-type applied measurement element due to its strength and workability.

It is true that metal strain bodies have many advantages, but
On the other hand, for example, in a high temperature region of 200°C or higher, the elastic properties of metal deteriorate, resulting in unstable properties, and since the metal itself is electrically conductive, the electrical conductivity may interfere, for example, between electrodes while electricity is flowing. It may not be possible to use it for measurement targets for special purposes such as load measurement.

[Object of the Invention] An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a load measuring element that can be used for special purposes.

[Summary of the Invention] The gist of the present invention for achieving the above-mentioned object is a load measuring element characterized in that a strain gauge is attached to a strain-generating body formed by molding ceramic having electrical insulation properties.

[Embodiments of the invention] The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 is a perspective view of the strain body, and FIG. 2 is a longitudinal sectional view of the measuring element. The strain-generating body 1 is made of, for example, silicon nitride, zirconia oxide,
It is made of ceramic such as alumina, and has a circular shape with flanges 2.3 provided at the upper and lower ends. A strain gauge 4 is attached to the cylindrical outer surface of the strain body l. The strain body 1 is manufactured by molding into a predetermined shape before firing. The strain-generating body 1 is housed in a metal protective opening 05, and flanges 2.3 at the upper and lower ends are adapted to slightly protrude upward and downward from the end surface of the protective cylinder 5. The outer peripheral surface of the flange 2.3 is in contact with a rubber O-ring 6 fitted into a groove on the inner surface of the protective cylinder 5, and the strain-generating body 1 is held in the protective cylinder 5. In addition, the protective cylinder 5
A connector 7 for taking out the lead wires of the strain gauge 4 is provided on the side of the strain gauge 4 .

By doing so, the strain-generating body 1 can obtain almost the same characteristics as the conventional strain-generating body 1 made of metal, but its characteristics are better than those made of metal, especially at high temperatures, and the vapor deposition When the strain gauge 4 is formed, it can be used even in an atmosphere of about 800°C. In addition, depending on the type of ceramic, the abrasion resistance is often better than that of metal.Furthermore, since the strain-generating body 1 is held from the surrounding area by the metal protective cylinder 5, Distorted body l
Even if it is destroyed, the presence of the protective cylinder 5 prevents major damage to the surrounding equipment to be protected.

FIG. 3 shows a case where this measuring element is applied to an electrode pressing force measuring device for an arc welding machine. Arc welding machines apply electricity between electrodes to weld the metal objects sandwiched between them, but this pressing force has a large effect on welding characteristics, so it is necessary to measure this pressing force frequently. There is. However, it is not preferable in terms of work efficiency to cut off the electricity to the electrodes every time the pressing force is measured, and it is desired to carry out the measurement while the electricity is being applied. However, due to the characteristics of the electrode! The measuring element that is interposed between the electrodes and measures the pressing force needs to be made of a non-conductive material.

The strain body 10 in this case is made of ceramic as described above, and its upper and lower surfaces are covered with electrodes 1 shown by dotted lines.
Recesses 10a and 10b are provided to prevent 1.12 from slipping. Further, a strain gauge (not shown) is attached to the side surface of the strain body 10, and a metal protection cylinder 13 is attached around the strain body 10 to protect the strain body 10. The gripping rod 14 pulled out from the cylinder 13 also serves as a lead wire for the strain gauge.

When a measuring device having such a configuration is inserted between the electrodes 11 and 12 to measure the pressing force between the electrodes 11 and 12, the pressure between the electrodes 11 and 12 is measured.
．． Even when a voltage is applied between the strain body 10
Measurement is possible because it is an electrical insulator.

[Effects of the Invention] As explained above, since the load measuring element according to the present invention uses a ceramic strain body, it is possible to perform measurements in high-temperature regions that were impossible with conventional metal strain bodies. Alternatively, since the strain-generating body is a conductor, it becomes possible to measure a measurement target that could not be measured.

[Brief explanation of the drawing]

The drawings show an embodiment of the load measuring element according to the present invention, and the first
FIG. 2 is a perspective view of a strain body, FIG. 2 is a longitudinal sectional view of a load measuring element, and FIG. 3 is a side view of a measuring device applied to measuring the electrode pressing force of an arc welder. Reference numerals 1 and 10 indicate a strain body, 2.3 a flange, 4 a strain gauge, 5 and 13 a protective cylinder, and 11.12 an electrode. Patent applicant: Showa Sokki Co., Ltd.

Claims (1)

[Claims] 1. A load measuring element characterized by having a strain gauge attached to a strain-generating body formed by molding ceramic having electrical insulation properties.