JPH0222651Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a double-sided shear type load cell, and its purpose is to improve the hysteresis phenomenon.

1 to 3 show a conventional double-sided shear type load cell. Reference numeral 1 denotes a load cell main body, which is composed of end portions 3a and 3b, which are located on both sides of the intermediate portion 2 and connected to the fixed side, on which a load G acts on the intermediate portion 2. Reference numeral 4 denotes a mounting base for the load cell body 1, which corresponds to the bottom surface of a pit in a truck scale, for example. Mounting blocks 5a and 5b are interposed between the ends 3a and 3b of the load cell main body 1 and the mounting base 4 to support the load cell main body 1, and 6a and 6b are fixing bolts. Also, 7
Reference numerals a to 7d denote strain cages for shear detection, which are attached to the thin wall portions 9a and 9b formed by drilling the through holes 8a and 8b, and are attached to the center portion 10 between the thin wall portions 9a and 9b. The load G acts through the side spherical seat 11. Reference numeral 12 indicates a steel ball, and reference numeral 13 indicates an upper spherical seat, which is attached to the girder 14 of the deck, for example, in the aforementioned truck scale.

Conventionally, in the lower spherical seat 11, the lower surface of the lower spherical seat 11 abuts the upper surface of the intermediate portion 2, as shown in FIG. It engages with a recess 16 formed on the upper surface of 2.

Therefore, the load on the load cell body 1 is the same as that of the steel ball 1.
2→Lower spherical seat 11→The contact surface 17 between the lower surface of the lower spherical seat 11 and the load cell body 1 is transmitted.
However, in such a transmission path, friction occurs at the contact surface 17 between the lower surface of the lower spherical seat 11 and the load cell main body 1, and a hysteresis phenomenon occurs in the output voltage of the load cell main body. This hysteresis phenomenon is particularly harmful to high-precision weighing devices, and it is desirable to reduce the hysteresis phenomenon.

Therefore, the present invention provides a catch whose lower end is fitted into contact with the bottom of a recess formed in the center of the upper surface of the middle part of the load cell main body, and eliminates friction between this catch and the upper surface of the middle part. The above-mentioned problems are avoided by applying a load to the device.Examples of the present invention will be described below with reference to FIGS. 4 to 8.

Reference numeral 1' denotes a load cell main body, which is composed of an intermediate part 2' on which the load G acts, and end parts 3a' and 3b' located on both sides of this intermediate part 2' and connected to the fixed side. Thin wall portion 20a formed by drilling through holes 18a to 18d and forming recess 19,
Strain gauges 7a to 7d are attached to 20b,
The load G acts on the center portion 10' of the thin portions 20a and 20b via the lower spherical seat 11'.
Reference numeral 21 denotes a mounting bracket interposed between the load cell body 1' and the mounting base 4, and has both ends 22a and 22b.
supports the ends 3a' and 3b' of the load cell body 1' from below, and connects the ends 22a and 22b.The intermediate part 2' of the load cell body 1' is on the surface of the load cell body 1' side of the central part 22c that connects the ends 22a and 22b. A support block 24 having a predetermined thickness H is fixed to the surface of the center portion 22c on the mounting base 4 side except for both ends 22a and 22b. Numerals 25a and 25b are fixing bolts for fixing the support block 24 to the mounting base 4.

As shown in FIG.
6, the spherical seat 27 is fitted until the lower end of the spherical seat 27 contacts the bottom surface 28 of the recess 26, and a through hole 29 slightly larger than the spherical seat 27 is bored in the center of the portion of the spherical seat 27 exposed from the recess 26. Bracket 3 for preventing steel balls from falling, with a part 30 of a spherical seat formed on the top surface
1 is installed. In normal use, the load G is directly transmitted to the bottom surface 28 of the recess 26 via the steel ball 12 and the spherical seat 27, and then to the central portion 10' of the load cell body 1'. In this state, the steel ball 12 and the bracket 31 are not in contact with each other.

With this configuration, the load G acts on the bottom surface 28 of the recess 26 via the spherical seat 27, and no frictional force is generated between the upper surface of the central portion 10' and the spherical seat 27 as in the conventional case, so hysteresis is eliminated. The occurrence of the phenomenon can be reduced.

In the above embodiment, the lower end of the spherical seat 27 was in contact with the bottom surface 28 of the recess 26 with its entire wide bottom surface, but this can be done by cutting off the outer circumference of the lower end as shown in FIG. The load G is concentrated in the center and a more favorable result can be obtained.

In addition, in the above embodiment, the load cell body 1'
Although the shape is different from that of the load cell body 1 shown in FIGS. 1 to 3, the same effect can be obtained with the load cell body 1.

As explained above, according to the present invention, there is a catch seat that is fitted so that its lower end comes into contact with the bottom surface of the recess formed at the center of the upper surface of the middle part of the double-sided shear type load cell body, and a seat that is placed on top of the catch seat. and a steel ball having a through hole slightly larger than the seat in the center and having a part of a spherical seat formed on the upper surface so as to be attached to the part exposed from the recess of the seat. A fall prevention bracket is provided, and the load is applied to the bottom surface of the recess formed at the center of the upper surface of the intermediate portion via the steel ball and the catch, so that the lower end of the catch is connected to the middle part of the load cell main body. The hysteresis phenomenon can be eliminated by a simple configuration in which the recess is fitted so as to come into contact with the bottom surface of a recess formed in the center of the upper surface, and this effect is particularly noticeable in highly accurate weighing machines.

[Brief explanation of drawings]

Figures 1 to 3 show a conventional double-sided shear type load cell, with Figure 1 being a front view, Figure 2 being a plan view of the load cell main body, and Figure 3 being a longitudinal sectional view of the lower spherical seat. 4 to 8 show embodiments of the present invention,
Figure 4 is the front view, Figure 5 is the side view, Figure 6 is the 4th
7 and 8 are vertical cross-sectional views of the lower spherical seat portion, and FIG. 8 is a vertical cross-sectional view of another embodiment of FIG. 7. 1, 1'...Load cell body, 2...Intermediate part,
3a, 3b...End part, 4...Mounting base, 5
a, 5b...Mounting block, 6a, 6b...Fixing bolt, 7a-7d...Strain gauge, 8
a, 8b...Thin hole, 9a, 9b...Thin wall part, 1
0...Central part, 11, 11'...Lower spherical seat, 1
2...Steel ball, 13...Upper spherical seat, 18a, 18
b...Through hole, 19...Recess, 20a, 20b...
... Thin wall portion, 26 ... Concave portion, 27 ... Spherical seat, 28
...Bottom surface of recess 26, 29...Through hole, 30...
Part of the spherical seat, 31...Bracket to prevent falling.

Claims (1)

[Scope of utility model registration request] A double-sided shearing type load cell main body consisting of an intermediate part on which a load is applied and end parts located on both sides of this intermediate part and connected to a fixed side, and a bottom surface of a recess whose lower end is formed in the center of the upper surface of the intermediate part. A steel ball placed on the catch, and a through hole slightly larger than the catch in the center so as to be attached to the part exposed from the recess of the catch. A steel ball drop prevention bracket having a hole bored therein and a part of a spherical seat formed on the upper surface thereof is provided, and the bottom surface of the recess formed at the center of the upper surface of the intermediate portion is provided through the steel ball and the seat. A double-sided shear type load cell configured to carry loads.