JPH0378637A - Detector of multiple component force and force - Google Patents

Abstract

PURPOSE:To eliminate an effect due to the thermal characteristic of strain gages by a construction wherein a load receiving part is provided in the central part of a frame body, T-shaped parts constructed of flexures are formed in four directions around the load receiving part and the flexures and the frame body are connected with each other by strain-generating parts constructed of four square pillars on the peripheries of which strain gages for detecting multiple component force are stuck. CONSTITUTION:When a force acts in the direction X on a load receiving part 12, a force applied to a square pillar part 13x in the direction of the X-axis is absorbed by a change in the form of a flat-plate flexure provided between a flexure 15x and a long groove 16x, and the force is made to act on a square pillar part 13y in the direction of the Y-axis through a flexure 15y in the direction of the Y-axis and detected from outputs of strain gages 18y stuck on the opposite lateral sides of the square pillar part 13y. A force in the direction of the Y-axis is detected, likewise, from outputs of strain gages 18x stuck on the square pillar part 13x in the direction of the X-axis, and moreover, a force in the direction of the Z-axis is detected from outputs of strain gages 18z stuck on the front and back sides of the square pillar parts 13x and 13y.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a multidirectional Kerr force detector for simultaneously measuring forces in three directions and force couples in three directions.

[Prior Art] Various types of multi-force load cells of this type have been known in the past. For example, Japanese Patent Publication No. 63-61609 discloses a load cell having a configuration as shown in FIG. 4.

This load cell has a load receiving part 2 arranged in the center of a frame 1, and a total of four prismatic parts 3, which are strain generating parts facing in the X direction and the Y direction, are connected between the frame 1 and the load receiving part 2. Supporting. A flexible flexure 4 is formed on the frame 1 side of the prismatic section 3, and a strain gauge 5 is formed on the load receiving section 2 side of the prismatic section 3.
is installed. Therefore, X.

Forces in the Y and Z directions are measured, and force couples centered on the X, Y, and Z axes can be measured.

[Problems to be Solved by the Invention] A multi-force load cell of the type described above is used, for example, when measuring component forces applied to the wheels of an automobile. , the axle will be inserted through this hole and measured. In this case, a considerably large force is applied to the load receiving part 2, and the mechanical rigidity between the load receiving part 2 and the prismatic part 3, which is an important element for a load cell, decreases, and the This causes mutual interference between component forces, which is a problem. In addition, frictional heat is generated due to rotation of the bearing interposed between the axle and the load receiving part 2, which is partially transmitted to the prismatic part 3, so the temperature characteristics of the strain gauge 5 attached to the prismatic part 3 are There is a high possibility that this may affect the measurement accuracy and introduce errors into the measurement accuracy.

An object of the present invention is to eliminate the above-mentioned drawbacks, and to provide a multi-force/force detector that is mechanically strong, has excellent couple sensitivity, and in which heat from the load receiver is difficult to be transmitted to the strain gauge. It is in.

[Means for Solving the Problem] In order to achieve the above object, in the multi-force/force detector according to the present invention, a load receiver is arranged in the center of the frame,
1 consisting of long grooves and flexures in four directions around the load receiving part;
forming a letter-shaped portion, and connecting the flexure and the frame with 4
It is characterized in that it is connected in a cross shape by strain-generating parts made of wooden prisms, and strain gauges for detecting multiple forces are attached around these strain-generating parts.

[Operation] The multi-force/force detector having the above configuration measures the force applied to the load receiving portion at the prismatic portion via the flexure.

[Example] The present invention will be explained in detail based on the example illustrated in FIGS. 1 to 3.

Figure 1 is a perspective view of the multi-force/force detector, Figure 2 is a plan view,
Figure 3 shows a cross-sectional view, and the main body of this multi-force/force detector is 1
It is formed by processing individual metal blocks. A load receiving part 12 is provided in the center of the ring-shaped frame 11, and between the frame 11 and the load receiving part 12 are four prismatic parts 13x, 13x, facing the X direction and the Y direction. 13y, connected by 13y. The load receiving portion 12 is provided with a male screw portion 14, and on the load receiving portion 12 side of each prismatic portion 13, flexures 15x, 15x, tsy, and 15y are provided, respectively, for twisting the prismatic portion 13 and reducing the transmission of couple forces. formed,
On the flexure 15 side of the load receiving portion 12, long grooves 16x, 16x, 16y are provided in directions orthogonal to the X direction and the Y direction, respectively.
16y is provided, and flat plate flexures 17x, 17 are provided to prevent tensile force and compressive force from being transmitted to the prismatic portion 13 as much as possible.
y is arranged. Further, strain gauges 18x, 18y, and 18z are attached to each surface of the prismatic portions 13x and 13y.

In the embodiment configured as described above, for example, the load receiving portion 12
When a force is applied in the X direction, the force applied to the square column 13x in the
The force is absorbed by the deformation of the flat plate flexure 17 provided between them, and the force acts on the prismatic portions 13y in the Y-axis direction via the flexure 15y in the Y-axis direction, and the strain attached to both sides of these prismatic portions 137 is absorbed. The force can be detected by the output of the gauge 18y. Further, force in the Y-axis direction can be detected by the output of the strain gauge 18x attached to the square column 13x in the X-axis direction. Furthermore,
Force in the X-axis direction can be detected by the outputs of strain gauges 18z, 18z attached to the front and back sides of the prismatic sections 13x, 13y. Furthermore, if the force is a composite force in the X-axis, Y-axis, and X-axis directions, it is sufficient to measure the force in each axis direction and detect these vectors.

Furthermore, for a couple centered on the X axis, flexure 15
x acts as a couple-reducing flexure and acts so as not to transmit torsion to the prismatic portion 13x, and the couple centered on the X axis is supported only by the prismatic portion 13y.

Therefore, the couple centered on the X-axis is the prismatic portion 13 in the Y-axis direction.
It is obtained by calculating the difference between the outputs of the strain gauges 18z attached to the front and back surfaces of the prismatic section 13x. It can be measured similarly by In addition, all flexures are unlikely to act on the couple centered on the X-axis, and can be directly measured using the outputs of the strain gauges 18x and tay attached to both sides of the prismatic sections 13x and 137. can do.

In the process of this measurement, even if a large force is applied to the load receiver 12, each square column 13 is firmly attached to the relatively rigid frame 11. This allows one component of force to be detected as extremely accurate bending strain while maintaining the ability to separate mutual interference of the applied force or force couple. Furthermore, even if the load receiving part 12 is heated by frictional force, such as when an axle is attached to the load receiving part 12, the heat will only pass through the strain gauge 1 through the flexures 17 and flexures 15, which have small cross-sectional areas.
Since the heat is transferred to the prismatic portion 13 to which the strain gauge 8 is attached, the heat transfer is extremely poor, and the strain gauge 18 is less affected by heat than in the past.

Furthermore, this load cell has flexures 17y to 17y sandwiching the male threaded portion 14, which is the point where the couple is generated, and flexures 17x to 17y.
The length between 17x and 17x is about 1/2 shorter than the length between flexures 6y and 6y and between flexures 6x and 6x of the conventional load cell shown in FIG. The detection sensitivity is nearly twice as good.

[Effect of the invention] As explained above, the multi-force/force detector according to the present invention has the following effects:
The prismatic part that supports the load receiver is firmly attached to the frame, and a flexure with a small cross-sectional area is provided on the load receiver side, so the load receiver is held stably. The amount of heat transferred to the strain gauge is small, there is little risk of affecting the thermal characteristics of the strain gauge, and the detection sensitivity for force couples is improved to about twice that of the conventional structure.

[Brief explanation of drawings]

Drawings 1 to 3 show an embodiment of the multi-force/force detector according to the present invention, in which Fig. 1 is a perspective view, Fig. 2 is a plan view, Fig. 3 is a sectional view, and Fig. 3 is a cross-sectional view. FIG. 4 is a perspective view of a conventional multi-force load cell. 11 is a frame body, 12 is a load receiving part, 13 is a prismatic part, 15
．． 17 is a flexure, 16 is a long groove, and 18 is a strain gauge.

Claims (1)

[Claims] 1. A load receiving part is placed in the center of the frame, a T-shaped part consisting of a long groove and a flexure is formed in four directions around the load receiving part, and four T-shaped parts are formed between the flexure and the frame. A multi-force/force detector characterized in that the parts are connected in a cross shape by strain-generating parts made of prisms, and a strain gauge for detecting multi-forces is attached around these strain-generating parts.