JP7091545B2 - Torque sensor - Google Patents

Description

The present invention relates to a torque sensor that detects torque.

Generally, a sensor that detects torque by elastic deformation of a member is known. (See Patent Document 1).

Japanese Unexamined Patent Publication No. 2007-40774

However, in the case of a sensor that detects torque by elastic deformation of a member, in order to increase the sensitivity of the sensor, it is necessary to make the elastically deformable member easy to deform, but if the member is easily deformed, an excessive load is applied. If so, the durability of the sensor tends to decrease.

An object of the embodiment of the present invention is to provide a torque sensor in which the sensitivity of the sensor to torque in the measuring direction is increased and the durability to torque in other directions is improved.

The torque sensor according to the viewpoint of the present invention is located in the first region formed in an annular shape and inside the first region portion on a concentric circle with the first region portion, and is formed in an annular shape. The region portion, a plurality of first beam portions connecting the inside of the first region portion and the outside of the second region portion, and the inside of the first region portion and the outside of the second region portion are connected. The width of the connection portion with the first region portion or the second region portion is narrower than the width of the central portion between the first region portion and the second region portion, and a hole is provided in the central portion. The second beam portion having a rectangular shape is fixed to the inside of both ends of the second beam portion so as to straddle the hole of the second beam portion, and is relative to the first region portion and the second region portion. It is equipped with a strain-causing body for detecting various displacements.

According to an embodiment of the present invention, it is possible to provide a torque sensor in which the sensitivity of the sensor to distortion in the measuring direction is increased and the durability to torque in other directions is improved.

The block diagram which shows the structure of the torque sensor which concerns on 1st Embodiment of this invention. An enlarged view of the vicinity of the strain detection beam portion of the torque sensor according to the first embodiment. An enlarged view of the vicinity of the strain detection beam portion of the torque sensor according to the second embodiment of the present invention. An enlarged view of the vicinity of the strain detection beam portion of the torque sensor according to the third embodiment of the present invention. An enlarged view of the vicinity of the strain detection beam portion of the torque sensor according to the fourth embodiment of the present invention.

(First Embodiment)
FIG. 1 is a configuration diagram showing a configuration of a torque sensor 10 according to the first embodiment of the present invention.

The torque sensor 10 is a sensor for detecting the torque of the Z-axis moment Mz with the Z-axis (direction perpendicular to the drawing) as the rotation axis. For example, the torque sensor 10 is mounted on a robot or the like.

The torque sensor 10 includes a first region portion 1, a second region portion 2, a plurality of beam portions 3, a plurality of strain detecting beam portions 4, and a plurality of strain generating bodies 5.

The first region portion 1, the second region portion 2, the plurality of beam portions 3, and the plurality of strain detecting beam portions 4 are integrally formed of a material such as metal. The first region portion 1 is formed in an annular shape. The second region portion 2 is formed in an annular shape having a diameter smaller than that of the first region portion 1. The second region portion 2 is located inside (center side) of the ring of the first region portion 1 on concentric circles. The plurality of beam portions 3 and the plurality of strain detecting beam portions 4 extend radially from the second region portion 2 and are provided so as to connect the inside of the first region portion 1 and the outside of the second region portion 2. The beam portion 3 has a role of connecting the first region portion 1 and the second region portion 2. In addition to the same role as the beam portion 3, the strain detecting beam portion 4 is provided with a strain generating body 5 for measuring strain. Any number of beam portions 3 may be provided. The strain detecting beam portion 4 is provided at least as many as the number of strain generating bodies 5.

The first region portion 1 is a portion attached to a load that receives torque. For example, the first region portion 1 is attached to a movable portion such as a robot's hand or arm. The second region portion 2 is a portion attached to a power source that generates torque. For example, the second region portion 2 is attached to a motor, a speed reducer, or the like.

The strain-causing body 5 is provided in the strain detecting beam portion 4 so that a force due to the relative displacement between the first region portion 1 and the second region portion 2 is applied. The strain-causing body 5 has, for example, a rectangular shape. Any number of strain generating bodies 5 may be provided.

The strain generator 5 includes a strain gauge that acts as a sensor for detecting strain. The strain gauge has, for example, an elongated shape, and is provided so that the longitudinal direction of the strain generating body 5 coincides with the longitudinal direction of the strain gauge. Strain gauges are configured to cause electrical displacement when deformed. The strain gauge may be any strain gauge as long as it causes an electrically detectable displacement. For example, the strain gauge may change the electric resistance or generate a voltage depending on the amount of deformation. The torque sensor 10 measures the torque by detecting these electrical displacements from the strain-causing body 5 (strain gauge).

For example, the strain-causing body 5 is used as follows. When torque is applied to the torque sensor 10, a pair of strain-causing bodies 5 are provided at positions where stresses that are symmetrical to each other are applied (positions that are symmetrical or vertically symmetrical). The force in the direction not to be measured is prevented from being detected by canceling the output of each strain gauge of the pair of strain generators 5. As a result, the torque sensor 10 detects only the torque in the measurement direction (Z-axis moment Mz).

FIG. 2 is an enlarged view of the vicinity of the strain detection beam portion 4 of the torque sensor 10 according to the present embodiment.

The strain-causing body 5 has a direction in which the strain detecting beam portion 4 connects the first region portion 1 and the second region portion 2 (hereinafter referred to as “connection direction”) and a longitudinal direction of the strain-causing body 5 (or It is arranged in the center of the strain detecting beam portion 4 in a direction in which the strain gauge is parallel to each other (longitudinal direction of the strain gauge). The strain detecting beam portion 4 is configured as follows so that the force of the Z-axis moment Mz can be easily detected.

The strain detection beam portion 4 has a shape in which the width of the connecting portion with the first region portion 1 and the second region portion 2 is narrower than the width of the central portion between the first region portion 1 and the second region portion 2. be. Specifically, both sides R of the strain detecting beam portion 4 are formed in a curve that swells from the connecting portion (both ends) of the first region portion 1 or the second region portion 2 toward the central portion.

A hole H1 is provided in the central portion of the strain detecting beam portion 4. The hole H1 is located in the central portion in the longitudinal direction of the strain-causing body 5 to be arranged. The strain generating body 5 is fixed to the strain detecting beam portion 4 at both ends. The central portion other than both ends of the strain-causing body 5 is not fixed anywhere and becomes a floating shape in the air. That is, the strain-causing body 5 is provided in the strain detecting beam portion 4 so as to straddle the hole H1.

By making both ends of the strain detection beam 4 narrower than the center, even if a force other than the Z-axis moment Mz is applied, the width of both ends of the strain detection beam 4 is narrow (dotted line in FIG. 2). Make sure that the deflection is concentrated in the area surrounded by. As a result, the force applied to the strain generating body 5 by a force other than the Z-axis moment Mz is reduced. Further, by providing a hole H1 in the center of the strain detecting beam portion 4 and fixing the strain generating body 5 at both ends, the strain generating body 5 can be easily deformed by the force of the Z-axis moment Mz. .. The strain generating body 5 is fixed to the strain detecting beam portion 4 by welding or the like.

When fixing the strain-causing body 5 to the strain detection beam portion 4, by fixing it not at the end but at a portion W slightly inside the end, stress due to torque can be avoided from being concentrated on the end of the strain-causing body 5. Be done. However, if it is fixed at the end, stress due to torque is likely to be applied to the strain generating body 5. Therefore, in order to increase the sensitivity of the sensor, it may be fixed at the end.

According to the present embodiment, regarding the strain detection beam portion 4, the width of the connection portion between the first region portion 1 and the second region portion 2 is the central portion between the first region portion 1 and the second region portion 2. A hole H1 is provided at a position located in the central portion of the strain-causing body 5 so as to be narrower than the width of the strain-generating body 5, and both end portions of the strain-causing body 5 are fixed to the strain detecting beam portion 4. As a result, the sensitivity of the sensor to the torque of the Z-axis moment Mz can be increased, and the durability to the torque in the direction other than the Z-axis moment Mz can be improved.
(Second embodiment)
FIG. 3 is an enlarged view of the vicinity of the strain detection beam portion 4A of the torque sensor 10A according to the second embodiment of the present invention.

The torque sensor 10A replaces the strain detection beam portion 4 with the strain detection beam portion 4A in the torque sensor 10 according to the first embodiment shown in FIG. Other points are the same as those of the first embodiment.

In the strain detection beam portion 4 according to the first embodiment, the strain detection beam portion 4A uses the auxiliary beam portion BM in the width direction (perpendicular to the connection direction) of the strain detection beam portion 4 according to the first embodiment. It is provided in the central portion of the hole H1 in parallel with the direction of). The two holes H11 and H12 correspond to the holes H1 according to the first embodiment divided by the auxiliary beam portion BM. The auxiliary beam portion BM does not necessarily have to be perpendicular to the connection direction as long as the two holes H11 and H12 are provided so as to be divided into the first region portion 1 side and the second region portion 2 side. Other points are the same as those of the strain detecting beam portion 4 according to the first embodiment.

The strain-causing body 5 is located on the central portion of the auxiliary beam portion BM. The strain-causing body 5 is not fixed to the auxiliary beam portion BM, but may be fixed.

By forming the strain detection beam portion 4A into a shape provided with the auxiliary beam portion BM, the shape includes the H-shaped portion as shown by the dotted line in FIG. This H-shaped portion is easily deformed with respect to the force in the direction of the Z-axis moment Mz, but is not easily deformed with respect to the force in the direction of the Y-axis moment My.

According to this embodiment, in addition to the action and effect according to the first embodiment, the following action and effect can be obtained.

The strain detection beam portion 4A is easily deformed with respect to a force in the direction of the Z-axis moment Mz by providing the auxiliary beam portion BM, but is easily deformed by a force in a direction other than the Z-axis moment Mz including the Y-axis moment My. On the other hand, the shape can be made difficult to deform. As a result, the sensitivity of the sensor to the torque in the direction of the Z-axis moment Mz is not lowered, and the durability against the external force in the direction other than the Z-axis moment Mz can be improved.
(Third embodiment)
FIG. 4 is an enlarged view of the vicinity of the strain detection beam portion 4B of the torque sensor 10B according to the third embodiment of the present invention.

The torque sensor 10B replaces the strain detection beam portion 4 with the strain detection beam portion 4B in the torque sensor 10 according to the first embodiment shown in FIG. Other points are the same as those of the first embodiment.

The strain detection beam portion 4B is a hole H1 in the vicinity of each of the connection portion with the first region portion 1 and the connection portion with the second region portion 2 in the strain detection beam portion 4 according to the first embodiment. The lightening portion L1 is provided on the extension line in the connection direction from the to. Other points are the same as those of the strain detecting beam portion 4 according to the first embodiment.

The lightening portion L1 is formed so as to be lighter than the portion of the strain detecting beam portion 4B other than the lightening portion L1. The lightening portion L1 may be formed in a recess so as to be thinner than other portions, or may be formed so as to have a hole. The lightening portion L1 may be provided only in one of the connection portion with the first region portion 1 and the connection portion with the second region portion 2. Moreover, even if it is provided in both, each shape may be different.

In particular, when a force is applied in the Z-axis direction, the lightening portion L1 concentrates the deflection due to this force on this portion, and applies a force applied to the central portion of the strain detecting beam portion 4B provided with the strain-causing body 5. Reduce.

According to this embodiment, in addition to the action and effect according to the first embodiment, the following action and effect can be obtained.

By providing the lightening portion L1 in the strain detecting beam portion 4B, it is possible to reduce the force applied to the central portion provided with the strain generating body 5 with respect to the force in the Z-axis direction. As a result, the strain-causing body 5 can reduce the strain due to the force in the Z-axis direction, and can improve the sensitivity of the sensor to the torque in the direction of the Z-axis moment Mz.
(Fourth Embodiment)
FIG. 5 is an enlarged view of the vicinity of the strain detection beam portion 4C of the torque sensor 10C according to the fourth embodiment of the present invention.

The torque sensor 10C is the torque sensor 10 according to the first embodiment shown in FIG. 2, in which the strain detection beam portion 4 is replaced with the strain detection beam portion 4C. Other points are the same as those of the first embodiment.

The strain detection beam portion 4C is the strain detection beam portion 4 according to the first embodiment, provided with the auxiliary beam portion BM according to the second embodiment and the lightening portion L1 according to the third embodiment. Is.

According to this embodiment, in addition to the action and effect of the first embodiment, the action and effect of each of the second embodiment and the third embodiment can be obtained.

The present invention is not limited to the above-described embodiment, and components may be deleted, added, or modified. Further, a new embodiment may be obtained by combining or exchanging components for a plurality of embodiments. Even if such an embodiment is directly different from the above-described embodiment, the description having the same purpose as that of the present invention is omitted as it has been described as the embodiment of the present invention.

1 ... 1st region, 2 ... 2nd region, 3 ... Beam, 4 ... Strain detection beam, 5 ... Distortion body, 10 ... Torque sensor.

Claims (1)

The first region formed in a ring shape and
Inside the first region portion, a second region portion located concentrically with the first region portion and formed in an annular shape,
A plurality of first beam portions connecting the inside of the first region portion and the outside of the second region portion, and
The inside of the first region portion and the outside of the second region portion are connected, and the width of the connection portion with the first region portion or the second region portion is the width of the first region portion and the second region portion. A second beam portion narrower than the width of the central portion between the two beams and having a hole in the central portion.
It is fixed inward of both ends of the second beam portion so as to straddle the hole of the second beam portion, and causes strain for detecting the relative displacement between the first region portion and the second region portion. A torque sensor characterized by having a body.

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