JPS63256832A - Load cell - Google Patents

Abstract

PURPOSE:To easily form a load cell which has no characteristic deterioration with high accuracy by fitting both ends of a ceramics plane plate where strain gauges are formed to a fixed body and a load receiving body by shrinkage. CONSTITUTION:The four strain gauges 5 which are bridge-coupled with one another are stuck on the top and reverse surface of the deformation part 4 of a flat plate type strain inducer 1 made of ceramic of Al2O3, etc. One end of this strain inducer 1 is coupled with the coupling groove 7 of the fixed body 6 by shrinkage fitting and the other end is coupled with the coupling groove 11 of the load receiving body 10 by shrinkage fitting to form a load cell main body. Then when a load is placed thereupon on a load receiving hole 12, the load cell deforms as shown in a figure and the resistance values of the strain gauges 5 vary, so that an electric signal corresponding to the load is obtained. Consequently, even when the main body is made of ceramics, the load cell having no deterioration in characteristics is formed with high accuracy at low cost because of the shrinkage fitting.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a load cell that converts a load into an electrical signal, and particularly relates to a load cell using ceramics.

BACKGROUND OF THE INVENTION Conventionally, load has been detected using a strain gauge whose resistance changes depending on the degree of mechanical deformation, but there is a load cell whose main body, which deforms under load, is made of ceramic. The load cell body has a parallelogram shape with a fixed body fixed to a fixed part, a load receiver to which a receiving plate is connected, and two arms extending parallel to each other. , strain gauges are formed at positions that expand and contract when a load is applied to the load receiver, and these strain gauges are bridge-connected to obtain an electrical signal corresponding to the load.

Problems to be Solved by the Invention Load cell bodies exhibiting such deformation have been formed of ceramics, but there are problems in that the structure is complicated and the cost is high.

Means for Solving the Problem: One strain-generating body is made of flat ceramic and has a strain gauge formed on its surface that is bridged to each other, and an insert or a hole is installed at one end of the second strain-generating body. A load cell main body is formed by a fixed body connected to a fixed part by a bottom, and a load receiver connected to the other end of the strain body by an insert or a bottom.

The strain-generating body made of ceramics, which is difficult to manufacture, has a flat plate shape, and the fixing body and load receiving part are separate from the strain-generating body, so they can be easily formed with high precision. Since the integration at the joint part is performed by an insert or the bottom of a pit, the joint state is reliable and does not cause characteristic deterioration.

Embodiment A first embodiment of the present invention will be explained based on FIGS. 1 to 3. First, a flat strain body 1 is formed of ceramics such as At, 03, and ZrO. This strain-generating body 1 has a rectangular shape, has two coupling holes 2 formed at each end, and has two deformed parts 4 formed by semicircular notches 3 extending inward from both side edges. There is. Four strain gauges 5 are attached to the front and back sides of the deformed portion 4 to be bridge-bonded to each other.

Next, a rectangular parallelepiped-shaped fixing body 6 made of metal is provided, and the second fixing body 6 has a coupling groove 7 formed therein to match the thickness of the strain-generating body 1, and a fixing part 8 such as a base.
A fixing hole 9 for fixing is formed.

Further, a load receiver 10 made of metal is formed. This load receiver 10 also has a coupling groove 1 in accordance with the thickness of the strain body 1.
1 is formed, and a protruding piece 13 in which a load receiving hole 12 is formed is formed below.

The strain-generating body 1, which is attached to the bottom of the pit, is coupled to the respective coupling grooves 7 and 11 of the fixed body 6 and the load receiver 10 formed in this way. When the flexure element 1, the fixed body 6, and the load receiver lO are integrated in this manner, the load receiver of the protruding piece is arranged such that the hole 12 is located at the center of the deformable portion 4 of the flexure element 1. Positioned.

In such a configuration, the load receiver connects the hole 12 with a saucer (not shown). That is, the load receiver is connected with a bolt in the hole 12, and a receiver plate is attached below the bolt. When an object to be weighed is placed on this tray, the strain body 1 deforms as shown in FIG. 3 due to its weight. This deformation state is large in the deformation part 4, and the surface length of the deformation part 4 expands and contracts, so the resistance value of the strain gauge 5 changes and an electrical signal corresponding to the load is generated. can get.

At this time, since the shape of the strain-generating body l made of ceramics is simple, it is easy to manufacture, and since the fixed body 6 and the load receiver 10 are connected through the bottom of the hole, they can be surely integrated. The measured values are stable.

In the above embodiment, the connection between the flexure element 1 and the fixed body 6 and the connection between the flexure element 1 and the load receiver 1° were explained at the bottom of the pit. Alternatively, the fixed body 6 and the load receiving body 10 may be made of a die-cast alloy made of aluminum or zinc, or the strain-generating body 1 made of ceramics as a synthetic resin may be integrated by an insert.

Further, the strain gauge 5 has been described as being attached in the above embodiment, but in practice, it may be formed on one side of the strain body 1 by thin film technology. In this case, two strain gauges 5 are formed on one surface of one deformed portion 4.

Next, a second embodiment of the present invention will be described based on FIG. In this embodiment, the fixed body 14 and the load receiver 15 are
9 and the fixed body 14 are connected by two thin parallel arms 16 to form an integral structure.
Grooves 17.18 are formed in each of the grooves 17.18 and the load receiver 15, and one strain-generating body made of a rectangular flat plate is integrated into these grooves 17.18 by an insert or a burnt surface. . Four strain gauges 20 similar to those in the embodiment described above are attached to the front and back sides of such a strain body 19.

In such a configuration, when a load is applied to the load receptor 15, the arm 16 deforms into a parallelogram shape and the strain body 19
is deformed into a certain shape, and an electrical signal corresponding to the load is generated by a resistance change based on the deformation of the strain gauge 20.

Effects of the Invention As described above, the present invention comprises a single strain-generating body made of flat ceramic and having strain gauges bridge-bonded to each other formed on its surface, and an insert at one end of the strain-generating body. Alternatively, the load cell body is formed by a fixed body that is connected to the fixed part by a burnt surface and a load receiver that is connected to the other end of the strain body by an insert or a burnt surface, The strain-generating body made of ceramics, which is difficult to manufacture, has a flat plate shape, and the fixing body and load receiving part are separate from the strain-generating body, so they can be easily formed with high precision. Since the integration at the bonding portion is performed by an insert or a burnt surface, the bonding state is reliable and there is no deterioration of characteristics.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a first embodiment of the present invention, FIG. 2 is an exploded perspective view thereof, FIG. 3 is a side view with a load applied, and FIG. 4 is a second embodiment of the present invention. It is a perspective view showing an example. 1...Strain body, 5...Strength, 6...Fixed body. 8... Fixed part, 10... Load receiver, 14... Fixed body, 15... Load receiver, 19... Flexible body, 20...
Strenge Applicant: Tokyo Electric Co., Ltd. J, 3 Figures, 33 are Figures.

Claims (1)

[Claims] A single strain-generating body made of flat ceramic and having strain gauges formed on its surface that are bridge-bonded to each other, and one end of this strain-generating body is connected to a fixed part by inserting or shrink-fitting. 1. A load cell comprising: a fixed body; and a load receiver coupled to the other end of the strain body by inserting or shrink fitting.