JPH0748058B2 - Maybe force / force detector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a force / force detector for simultaneously measuring forces in three directions and couples in three directions.

[0002]

2. Description of the Related Art For this type of multi-force load cell, various methods have been conventionally known, for example, Japanese Patent Publication No. 63-6160.
Japanese Unexamined Patent Publication No. 9 discloses a load cell configured as shown in FIG. In this load cell, a load receiving portion 2 is arranged in the central portion of a frame body 1, and a total of four prismatic portions 3 which are strain generating portions extending in the X direction and the Y direction between the frame body 1 and the load receiving portion 2 are provided. Supporting. A flexible flexure 4 is formed on the frame 1 side of the prism 3 and a strain gauge 5 is attached to the load receiver 2 side of the prism 3. Therefore, X,
It is possible to measure the forces in the Y and Z directions and to measure the couple forces centered on the X axis, the Y axis, and the Z axis, respectively.

[0003]

A multi-component load cell of the type described above is used, for example, when measuring the component force applied to the wheels of an automobile. In this case, the load receiving portion 2 is provided with a hole. The axle will be inserted through this hole for measurement. In this case, a considerably large force is applied to the load receiving portion 2, and the mechanical rigidity, which is an important element as a load cell, between the load receiving portion 2 and the prismatic portion 3 is reduced, and the force load cell is probably the maximum. However, since it is a straight prism, the distribution of the detected stress generated in the strain gauge is poor. Further, frictional heat is generated by the rotation in the bearing portion interposed between the axle and the load receiving portion 2, and the heat is transmitted to the prismatic portion 3 as partial heat generation, so that the temperature of the strain gauge 5 attached to the prismatic portion 3 is increased. Affect the characteristics,
There is a high possibility that an error may intervene in the measurement accuracy.

The object of the present invention is to eliminate the above-mentioned drawbacks, to have a mechanically strong structure, a good stress distribution, a uniform output, excellent couple sensitivity, and the strain gauge to receive heat from the load receiving portion. It is to provide a force / force detector that is difficult to transmit.

[0005]

In order to achieve the above object, in the multi-component force / force detector according to the present invention, a load receiving portion is arranged at the center of the frame body, and the center of the load receiving portion is arranged. Long grooves that are orthogonal to the X-axis and the Y-axis are provided at four locations around the load-receiving portion along the X-axis and the Y-axis that intersect each other and intersect each other, and a flat flexure is formed outside these long grooves. X between the flat plate flexure and the frame.
Connected in a cross shape with four strain-flexing parts that become wider toward the outside along the axis and the Y-axis, and affix a strain gauge for detecting force to the periphery of these strain-flexing parts. It is a feature.

[0006]

In the force / force detector having the above structure, the force applied to the load receiving portion is measured by the strain gauge at the strain generating portion having an equal stress section provided between the load receiving portion and the frame.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in FIGS.

FIG. 1 is a perspective view of a force / force detector, and FIG.
The figure shows a plan view and FIG. 3 shows a sectional view, and this force / force detector main body is formed by processing a metal block. A load receiving portion 12 is provided in the center of the ring-shaped frame body 11, and the space between the frame body 11 and the load receiving portion 12 is the X axis, and the Y axis is the Y axis.
Four flexures 13x, 13x, 13y, 13 along the axis
Connected by y. A male screw portion 14 is provided in the center of the load receiving portion 12, and each strain generating portion 13 reduces the transmission of a twist, that is, a couple, and goes from the load receiving portion 12 to the frame body 11 in order to equalize the stress. The groove 16 is formed in a constant stress cross section whose width becomes wider as the X-axis and the Y-axis of the load receiving portion 12 extend in directions orthogonal to the X-axis and the Y-axis, respectively.
x, 16x, 16y, 16y are provided, and the load receiving portion 12 and the strain-flexing portion 13 form an outer portion of the long grooves 16x, 16y so that the tensile force and the compressive force are not transmitted to the strain-flexing portion 13 as much as possible. Flat plate flexures 17x, 17x, 17y,
It is connected via 17y. In addition, the strain-flexing portion 13x,
Strain gauges 18x and 18y are attached to the respective side surfaces of 13y, and strain gauges 18z are attached to the front and back surfaces.

In the embodiment configured as described above, for example, when a force acts on the load receiving portion 12 in the X-axis direction, the force applied to the strain-flexing portion 13x in the X-axis direction is the strain-generating portion 13x.
Is absorbed by the deformation of the flat flexure 17x provided between the long groove 16x and the long groove 16x, acts only on the strain-flexing portion 13y in the Y-axis direction, and is output by the strain gauges 18y attached to both side surfaces of the strain-flexing portion 13y. The force can be detected. The force in the Y-axis direction can be detected by the output of the strain gauge 18x attached to the strain-flexing portion 13x in the X-axis direction. Further, the force in the Z-axis direction can be detected by the output of the strain gauge 18z attached to the front and back sides of the strain-flexing portions 13x and 13y. If the force is a combined force in the X-axis, Y-axis, and Z-axis directions, the force in each axis direction may be measured to detect these vector components.

Further, the inner end of the strain-flexing portion 13x, which becomes wider toward the outside with respect to the couple force centering on the X-axis, functions as a couple-reducing flexure so as not to transmit a twist to the strain-generating portion 13x. The couple acting around the X-axis is supported only by the strain-flexing portion 13y. Therefore, the couple about the X axis is obtained by calculating the difference between the outputs of the strain gauges 18z attached to the front and back surfaces of the strain-flexing portion 13y in the Y axis direction, and the couple about the Y axis. The same can be measured by using the strain gauge 18z attached to the front surface and the back surface of the strain-flexing portion 13x. Further, the couple about the Z axis can be directly measured using the outputs of the strain gauges 18x and 18y attached to both side surfaces of the strain-flexing portions 13x and 13y.

In the process of this measurement, even if a large force is applied to the load receiving portion 12, each strain generating portion 13 is firmly attached to the frame body 11 having a relatively large rigidity. The force applied to the receiving portion 12 or the couple force is detected as an extremely accurate bending strain while maintaining the separation ability of mutual interference. Even when the load receiving portion 12 is heated by frictional force, for example, when an axle is attached to the load receiving portion 12, the heat is applied to the strain gauge 18 only through the flat flexure 17 having a small cross-sectional area. Since it is transferred to the strain-generating portion 13, the heat transfer is extremely poor, and the strain gauge 18 is less affected by heat than before.

Further, the force / force detector according to the present invention has a flat plate-shaped flexure 1 which sandwiches a male screw portion 14 which is a couple generation point.
The length between 7y and 17y and between the flexures 17x and 17x is the same as that of the conventional flexure 6 of the load cell shown in FIG.
1/2 between y-6y and flexure 6x-6x
Since the length is short, the detection sensitivity is almost doubled for the same couple.

[0013]

As described above, in the multi-component force / force detector according to the present invention, since the load receiving portion is supported and the strain receiving portion having a narrow width is firmly attached to the frame body, The receiving part is held stably, and the amount of heat transferred from the load receiving part to the strain-flexing part side is small, so there is little risk of affecting the thermal characteristics of the strain gauge. In addition, the detection sensitivity to couple is 2 compared with the conventional structure.
It will be improved about twice.

[Brief description of drawings]

FIG. 1 is a perspective view.

FIG. 2 is a plan view.

FIG. 3 is a cross-sectional view taken along the Y axis.

FIG. 4 is a perspective view of a conventional multi-force load cell.

[Explanation of symbols]

 11 frame body 12 load receiving portion 13 strain generating portion 16 long groove 17 flat plate flexure 18 strain gauge

Claims (1)

[Claims] 1. A load receiving portion is arranged in a central portion of a frame body, and X-axis and Y are orthogonal to each other and have an intersection in the central portion of the load receiving portion.
These X-axis and Y-axis are provided at four places around the load receiving part along the axis.
Long grooves that are orthogonal to the axis are provided, flat plate flexures are formed on the outer sides of these long grooves, and the width becomes wider between the flat plate flexure and the frame body along the X axis and the Y axis toward the outside. Probably a force / force detector characterized in that four strain elements are connected in a cross shape, and a strain gauge for detecting a force is attached around the strain elements.