JP2604692B2 - 2 component force / 1 moment detector - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention belongs to the field of strain gauge type load transducers, and more particularly to a detection device capable of detecting two component forces and one moment simultaneously.

[Prior art] A strain gauge type load transducer converts weight, force, and torque into an electrical output using a strain gauge.
Transducers that simultaneously measure forces and torques in different directions are often used for measuring the shock absorption of automobiles and the operating characteristics of robots.

Conventionally, devices that simultaneously detect two-component force and one moment include devices shown in FIG. 6 (plan view), FIG. 7 (front view), and FIG. 8 (sectional view taken along the line ZZ). Used.

The two-component / one-moment detecting device includes a load receiving portion 51
And four strain columns 52 supporting both sides of the load receiving portion 51 by two each, and a seat body 53 supporting the other end of each strain column 52, and are integrally formed. A strain gauge (not shown) is adhered to each side surface of the strain column 52. As shown in FIG. 7, when a two-component force Fx, Fz and one moment My act on the load receiving portion 51. Then, the strain generated in the strain column 52 is converted into an electrical output by a strain gauge and detected, and Fx, Fz,
Allows you to measure My. The load receiving portion 51 has a screw hole 51a for connecting to the movable portion to be measured.
It is fixed using.

Here, the seat portion 53 is formed as a frame surrounding the load receiving portion 51, and a hole is formed in an appropriate position of the seat portion 53, and a screw is fixed to a fixed base. It is installed by the fixing means.

[Problems to be Solved by the Invention] In this type of two-component / one-moment detecting device, since the seat 53 serves as a fixed end of the strain column 52, the seat 53 is high. If it does not have rigidity, the linearity of the measurement data and the zero return characteristic when the load is removed deteriorates, and accurate measurement cannot be performed.

In this regard, the seat body 53 in the above-described conventional device is formed in a frame shape, but has a low rigidity. Even if the seat body 53 is fixed to the fixed base by screwing or the like, the load is slightly applied to the load receiving unit 51. There is a disadvantage in that the measurement results are deformed, and the linearity and the zero return characteristic of the measurement result are deteriorated.

On the other hand, this effect can be suppressed by designing the thickness and width of the frame, which is the seat body 53, to be large, or by strengthening the entire fixed installation conditions to achieve high rigidity. Problem arises.

Therefore, the present invention provides a two-component / one-moment detecting device which makes small-sized and high-accuracy measurement possible by making the fixed end condition of the strain-flexing column more complete by increasing the rigidity of the seat body. It was created for the purpose.

[Means for Solving the Problems] According to the present invention, a load receiving portion, four strain-bearing columns supporting two sides of each of the load receiving portions, and the other end of each strain-bearing column are supported. In a two-component / one-moment detecting device in which a seat body is integrally formed and a strain gauge is adhered to the side surface of each strain-causing column, the seat body is formed in a U-shape and between the side wall portions thereof. In which the load receiving portion is supported by strain columns.

Further, by forming a hole in a region of the bottom plate portion of the U-shaped seat body portion facing each of the strain-generating columns, it is possible to bond a strain gauge to the side surface on the hole side of each strain-generating column. It will be easier.

[Operation] In the two-component / one-moment detecting device of the present invention, the rigidity of the side wall portion, which is the fixed end of the strain-causing column, is reduced because the seat body has a U-shaped integral structure including the side wall portion and the bottom plate portion. Get higher. As a result, when the load is applied to the load receiving portion, the deformation of the seat portion becomes extremely small, and the fixed end conditions of the strain column are idealized, and the strain linearity of the strain column corresponding to the load is good. And the zero return characteristic when the load is removed is also improved. Further, since the side wall portion has sufficient rigidity even if its thickness and width are small, and it is not necessary to form the seat body as a frame and surround the load receiving portion as in the conventional device. The whole can be reduced in size.

On the other hand, in the present invention, since the seat body portion has a U-shape, it becomes difficult to adhere a strain gauge to the surface of the strain-generating column on the side of the bottom plate portion due to the presence of the bottom plate portion. Since the hole formed in the area facing the column enables the strain gauge to be bonded from the bottom side, positioning and bonding of the strain gauge can be performed in the same manner as in a normal case.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

FIGS. 1, 2, and 3 are a plan view, a cross-sectional view taken along the line XX, and a view of the two-component / one-moment detecting device, respectively.
FIG. 2 is a cross-sectional view taken along the arrow Y, where 1 is a load receiving portion, 2 is a strain column having a rectangular cross section, 3 is a seat portion (3a is a side wall portion of the seat portion,
Denotes a bottom plate portion of the seat body portion, which are formed as an integral structure. Further, the strain-flexing column 2 supports the load receiving portion 1 by connecting both sides of the load receiving portion 1 and both side wall portions 3a of the seat portion 3 in two grooves in the groove of the seat portion 3 with a total of four each. However, strain gauges 4 for detecting the shearing force are adhered to the four side surfaces of each strain column 2.

Further, a hole 5 is formed in a region of the bottom plate portion 3b of the seat body portion 3 facing each strain-flexing column 2. When the strain gauge 4 is bonded to the side surface of the base plate portion 3b side of the seat body portion 3 in the strain-causing column 2, if the gap between the side surface and the bottom plate portion 3b is narrow, positioning and bonding work becomes difficult. Therefore, bonding can be performed from the bottom surface side of the seat body portion 3 through the hole 5.

In the apparatus of this embodiment, a connection member (not shown) for connecting to a movable portion to be measured is screwed into a screw hole 6 formed in a load receiving portion 1.
To detect the force and torque acting on the load receiving portion 1 from the movable body, as shown in FIG.
The axial forces Fx and Fz and the torque My can be detected simultaneously.

That is, the strain gauges 4 forming Fx, Fz, and My are each composed of a total of eight pieces, and are electrically assembled as a bridge circuit as shown in FIG. Is measured as data corresponding to Fx, Fz, and My. Here, C and T indicate gauges that detect the compression direction and the expansion direction, respectively, when Fx, Fz, and My are acting in the directions of the arrows shown in FIG. .

In order to compare the accuracy of the device of the present embodiment with the device of the prior art, a strain gauge of the same standard was adhered to each of the strain generating columns 2 and 52, and the same load (Fx , Fz, My) on the load receivers 1,51. Although not shown, the strain column 2,
52 have the same cross-sectional shape.

As a result of this measurement, data as shown in Table 1 for Fx, Table 2 for Fz, and Table 3 for My were obtained, and their qualitative trends showed the relationship shown in FIG. became. That is, it has been proved that the device of the present embodiment has less nonlinearity and a better zero return characteristic than the conventional device for any kind of load.

In addition, the maximum dimension of the planar shape of the apparatus of this embodiment is two-thirds that of the conventional apparatus, and in terms of volume, it is about 7 times that of the conventional apparatus.
Since it is as small as 0%, the device of the present embodiment is much smaller than the conventional device.

Although not shown in the drawings, in order to prevent stress concentration, the strain-causing columns 2 and the side walls of the load receiving portion 1 and the seat portion 3 are formed.
It is desirable to form a corner or the like of the connection portion with 3a, and this means is also applied to the apparatus of this embodiment.

In this embodiment, a strain gauge for detecting a shear strain is attached to detect a two-component force and one moment, but a strain gauge for detecting a bending strain or a strain gauge for detecting a bending strain and a shear strain is applied. It does not matter.

[Effects of the Invention] The present invention is configured as described above, and has the following effects.

The two-component, one-moment detecting device adopts a structure in which the seat body is formed in a U-shape and the load receiving part is supported between the side walls by a strain-flexing column. Thus, it is possible to configure a detection device that is excellent in linearity and return-to-zero characteristics, and that can perform high-precision measurement while being compact.

In addition, by forming a hole in the region of the bottom plate portion of the seat body facing the strain-generating column, it is easy to bond the strain gauge to the lower surface side of the strain-generating column with high positional accuracy, further improving the accuracy of the device. To improve.

[Brief description of the drawings]

1 is a plan view of the apparatus of the embodiment, FIG. 2 is a sectional view of the same (a sectional view taken along the line XX in the plan view), FIG. 3 is a sectional view thereof (a sectional view taken along the line YY in the plan view), and FIG. FIG. 4 is an electric circuit diagram of the gauge bridge, FIG. 5 is a graph showing the qualitative tendency of the non-linearity between the embodiment apparatus and the conventional apparatus by taking the load on the horizontal axis and the output (strain) on the vertical axis. 6 is a plan view of the conventional device, FIG. 7 is a front view thereof, and FIG. 8 is a sectional view thereof (Z in FIG. 6).
-Z section). DESCRIPTION OF SYMBOLS 1 ... Load receiving part, 2 ... Strain generating column, 3 ... Seat part 3a ... Side wall part, 3b ... Bottom plate part 4 ... Strain gauge, 5 ... Hole

Claims (2)

(57) [Claims] 1. A load receiving portion, four strain-bearing columns supporting two sides of the load receiving portion each, and a seat portion supporting the other end of each strain-bearing column are integrally formed. In a two-component / one-moment detecting device in which a strain gauge is adhered to a side surface of each strain column, a seat body portion is formed in a U-shape, and a load receiving portion is formed between both side wall portions by a strain column. A two-component / one-moment detection device characterized by being supported by: 2. The two-component, one-moment detecting device according to claim 1, wherein a hole is formed in a region of the bottom plate portion of the seat body facing each strain-causing column.