JPS6225697Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an axial load detection device that detects an axial load from the shear force generated by the axial load.

As a conventional shaft load detection device, Figures 1 and 2
I found something like the one shown in the picture. Reference numeral 1 denotes an inner ring portion, and a bearing hole 2 for bearing a shaft is bored in the center of the inner ring portion. Reference numeral 3 denotes an outer ring portion attached to the bearing body, which is arranged concentrically with respect to the inner ring portion 1. The inner ring part 1 and the outer ring part 3 are connected by four horizontal beams 4 arranged in parallel on both sides of the bearing hole 2.
Strain gauges 6 are attached to the upper and lower surfaces of these beams 4, respectively. This load detection device detects the beam 4 by the load acting on the shaft fitted in the bearing hole 2.
The axial load is detected from the bending stress generated in the However, this load detection device had the following problems. First, since the bending moment of the beam 4 is as shown in FIG. 3b, even a slight movement of the load application point will affect the detection accuracy. Second, since the strain gauges are attached to the upper and lower surfaces of the beam, the detection accuracy is affected by torsional stress. Third, as shown in FIG. 3b, the bending moment changes significantly at the gage bonding position, so if the gage bonding position shifts, the detection accuracy will be affected. Due to these problems, great care was required in manufacturing.

In order to solve these problems, it is sufficient to detect the load from the shear force generated by the axial load. However, conventionally, load cells that detect shear force due to bending stress have been disclosed in, for example, US Pat.
Existed as disclosed in the specification of No.
There was nothing that could detect shear force due to axial load.

The object of this invention is to provide a load detection device that can detect load from shear force.

Below, this idea is shown in Figures 4 to 12.
The explanation will be based on two examples. The load detection device 7 of the first embodiment includes an inner ring portion 11, an outer ring portion 12, a beam 13, and a strain gauge 14. Inner ring part 1
As shown in FIG. 4, the bearing hole 1 is formed into an oval shape with a predetermined thickness dimension, and has a bearing hole 15 extending through the thickness direction in the center thereof.

The outer ring part 12 is an annular body arranged concentrically with the inner ring part 11 and has the same thickness dimension as the inner ring part 11. 16 is a flange portion for attaching the outer ring portion 12 to a bearing body (not shown).

The beam 13 is interposed between the outer ring portion 12 and the inner ring portion 11, and is arranged symmetrically and horizontally on both sides of the bearing hole 15. The beam 13 has an outer ring portion 12 and an inner ring portion 11.
are connected by their both end surfaces (dotted line portions in FIG. 4). The beam 13 is, as shown in FIG.
Recesses 19 are formed on both sides in the thickness direction, that is, on the front and rear sides, and the longitudinal cross-sectional shape is I-shaped.

As shown in FIG.
They are mounted at an angle of 45° and connected to form a Whiston bridge. The shear force applied to the beam 13 by this Wheatstone bridge is measured. The reason why the strain gauge 14 is provided approximately at the center of the beam 13 is that a large shear force can be measured at the center of the beam 13, as shown in FIG. 12b.

This load detection device 7 is manufactured as follows. A bearing hole 15 is drilled in the center of the flanged disk, and arc-shaped grooves 17 having straight parts at both ends are bored symmetrically above and below the bearing hole 15, and grooves 17 are formed symmetrically on both sides of the bearing hole 15 and with the front surface. A recess 19 is formed on both rear surfaces to form a beam 13 having an I-shaped cross section, and the recess 1
A strain gauge 14 is attached to the center of the strain gauge 9.

This load detection device 7, as shown in FIG.
It is attached to the bearing body 18 and used by fitting the shaft 8 into the bearing hole 15. This load detection device 7 detects the axial load from the shear force generated by the axial load.

The load detection device 20 of the second embodiment has a total of four beams 13 on both sides of the bearing hole 15 to form a roberval mechanism, as shown in FIGS. 9 to 11. Similar to the first embodiment, this load detection device also measures the axial load using shear force.

As shown in FIG. 7b, these axial load detection devices 7 and 20 detect the shear force that occurs constantly in the horizontal direction, so even if the load application point moves horizontally or the mounting position of the strain gauge Even if there is a slight shift in the horizontal direction, the detection accuracy will not be affected. Therefore, even if a large number of shaft load detection devices 7, 20 are manufactured, the accuracy of each device 7, 20 can be made uniform. In addition, the strain gauge 14 has recesses 19 and 1.
9 and has an I-shaped vertical cross section, the shear force is
As shown in Figure b, the strain gauge 14 can detect a shear force that is generated in a step shape and is several times the average shear force of the cross section. Since the strain gauge is installed near the center of curvature, the strain gauge 14 receives extremely little torsion and bending stress, and a highly sensitive detector with extremely little torsional and bending interference can be obtained. In addition, regarding the linearity of the Wheatstone bridge composed of strain gauges, due to the nature of shear stress, the resistance change of all gauges is the same, so a highly accurate detection circuit is constructed in which strain and output voltage are proportional. Ru.

[Brief explanation of the drawing]

Fig. 1 is a front view of a conventional load detection device, Fig. 2 is a longitudinal sectional side view thereof, Fig. 3 a is an elastic diagram thereof, Fig. 3 b is a bending moment diagram thereof, and Fig. 4 is a first embodiment. 5 is a sectional view taken along line A-A in FIG. 4, FIG. 6 is a sectional view taken along line B-B in FIG. 7, and FIG.
Figure b is a shear force diagram of the same, Figure 8 is a side view showing the state of use of the first embodiment, Figure 9 is a front view of the second embodiment, and Figure 10 is a cross-sectional view taken along line C-C in Figure 9. , FIG. 11 is a cross-sectional view taken along the line DD, and FIG. 12 a is a vertical cross-sectional view of the beam.
FIG. 12b is a shear force diagram in the longitudinal section of the beam. 11... Inner ring part, 12... Outer ring part, 13...
Beam, 14... strain gauge, 15... bearing hole, 18... bearing body, 19... recess.

Claims (1)

[Scope of utility model registration request] an inner ring part that is penetrated in the thickness direction by a bearing hole that supports a shaft on which a load is applied; an outer ring part that is arranged to surround this inner ring part and is attached to the bearing body;
A plurality of beams are provided symmetrically and horizontally on both sides of the bearing hole and connect the inner ring portion and the outer ring portion, and a plurality of beams are provided on both sides in the thickness direction of the beams, and a plurality of beams are provided horizontally and symmetrically on both sides of the bearing hole. a recess provided in each of the recesses, and a strain gauge installed approximately in the center of each recess in the height direction so as to detect the shear force generated in the beam due to the load applied to the inner ring portion. Detection device.