JP2024031356A - torque sensor - Google Patents

Abstract

To provide a torque sensor which detects a displacement by a limited space and has an increased detection accuracy for a torque.SOLUTION: A torque sensor 1 includes: a first structure 11 formed in the shape of a wheel; a second structure 12 formed in the shape of a smaller wheel than the first structure 11 and arranged in the inner peripheral side of the first structure 11; a protrusion unit 14 provided in the first structure 11, the protrusion unit protruding to the second structure 12; a sensor 2 provided in the second structure 12, the sensor detecting a physical amount which shows the distance between two members which is changed by contact with the protrusion unit 14 caused in a manner that the first structure 11 receives a torque Mz and relatively rotates to the second structure 12; and torque detection means for detecting the torque Mz on the basis of the physical amount detected by the sensor 2.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to torque sensors.

Generally, torque sensors are known that detect torque based on elastic deformation of a deformable body. For example, a torque sensor has been disclosed that detects torque by providing a beam in a deformable portion that causes elastic deformation of a deformable body and measuring the displacement of the beam (for example, see Patent Document 1).

JP 2018-200259 Publication

However, when detecting torque by measuring displacement due to elastic deformation, the space in which displacement occurs is often limited by the structure. For this reason, the magnitude of displacement that can be measured in a limited space is also limited, and it may not be possible to achieve sufficient torque detection accuracy.
The purpose of this embodiment is to provide a torque sensor that detects displacement in a limited space and improves torque detection accuracy.

According to this embodiment, it is possible to provide a torque sensor that detects displacement in a limited space and improves torque detection accuracy.

The torque sensor of the present embodiment includes: a first structure formed in a ring shape; a second structure formed in a ring shape smaller than the first structure and disposed on the inner peripheral side of the first structure; a protrusion provided on the first structure so as to protrude toward the second structure; and a protrusion provided on the second structure that causes the first structure to move toward the second structure by application of torque. a sensor that detects a physical quantity indicating a distance between two members that changes when the two members rotate relative to the body and come into contact with the protrusion, and the torque is determined based on the physical quantity detected by the sensor. and torque detection means for detecting the torque.

FIG. 1 is a top view showing the configuration of a torque sensor according to a first embodiment of the present invention. FIG. 2 is a configuration diagram showing the configuration of an arithmetic processing unit according to the first embodiment. FIG. 3 is a state diagram showing a method of detecting torque by the torque sensor according to the first embodiment. FIG. 7 is a top view showing the configuration of a torque sensor according to a second embodiment of the present invention.

(First embodiment)
FIG. 1 is a top view showing the configuration of a torque sensor 1 according to a first embodiment of the present invention. Note that the same parts in the drawings are denoted by the same reference numerals, and redundant explanations will be omitted as appropriate.

Torque sensor 1 is a sensor that detects torque Mz. Torque Mz is a moment about the z-axis (rotation axis direction) shown in FIG. Here, the x-axis, y-axis, and z-axis are orthogonal to each other. Note that the torque sensor 1 is not limited to the one described here, and may be changed to various shapes or configurations. Further, the torque sensor 1 may have any name as long as it detects at least torque (z-axis moment) Mz.

The torque sensor 1 includes a first structure 11 , a second structure 12 , a plurality of third structures 13 , a protrusion 14 , and two displacement sensors 2 .

In addition to the above-described configuration, the torque sensor 1 includes, for example, an arithmetic processing section 3 and wiring such as a flexible printed circuit (FPC) that electrically connects the displacement sensor 2 and the arithmetic processing section 3. Further, a case may be provided in the hollow portion located at the center of the second structure 12. For example, the case houses the arithmetic processing unit 3, a power cable, and the like.

The first structure 11, the second structure 12, and the third structure 13 are integrally formed as an elastic body. The first structure 11 and the second structure 12 are both formed in a ring shape and arranged concentrically. The diameter of the second structure 12 is smaller than the diameter of the first structure 11, and the second structure 12 is arranged inside (center side) of the first structure 11. Therefore, a ring-shaped space is formed between the first structure 11 and the second structure 12.

The third structures 13 are arranged radially (radially) at equal intervals in the circumferential direction in the annular space between the first structures 11 and the second structures 12. It has a role as a beam connecting the structures 12. Here, the four third structures 13 were provided at equal intervals at 90 degrees, but any number of third structures 13 may be provided and they may be provided at any interval.

For example, the first structure 11 is connected to a structure to be measured to which torque Mz is applied, and the second structure 12 is connected to a structure to which torque Mz is applied. The first structure 11 and the second structure 12 rotate relative to each other due to the torque Mz. Note that the first structure 11 may be connected to the structure to which the torque Mz is applied, and the second structure 12 may be connected to the structure to be measured.

For example, the material of the first structure 11, the second structure 12, and the third structure 13 is a metal such as stainless steel, but as long as it has sufficient mechanical strength against the applied force. , materials other than metal (such as resin) may be used.

The protrusion 14 is provided on the inner peripheral side of the first structure 11 so as to protrude toward the second structure 12 . The protrusion 14 has a rod shape. For example, the longitudinal centerline of the protrusion 14 passes through the center of rotation of the torque Mz. The tip of the protrusion 14 is located between the two displacement sensors 2 provided on the second structure 12 so as to be in contact with the two displacement sensors 2 . For example, the tip of the protrusion 14 is formed into a curved shape so as to smoothly contact the displacement sensor 2. Note that the protrusion 14 is not limited to the one described here, and may have any shape or arrangement.

The two displacement sensors 2 are provided on the outer peripheral side of the second structure 12 such that the tip of the protrusion 14 is located between the two displacement sensors 2. The two displacement sensors 2 are arranged symmetrically around the tip of the protrusion 14 . One of the two displacement sensors 2 detects clockwise torque Mz, and the other detects counterclockwise torque Mz.

Note that the torque sensor 1 may include any number of displacement sensors 2. The torque sensor 1 may include one displacement sensor 2 and may detect only the torque Mz in one rotational direction. Further, the torque sensor 1 may be provided with a plurality of displacement sensors 2 that detect torque Mz in one rotational direction. In this case, the torque Mz may be detected based on the detection results of the plurality of displacement sensors 2 (for example, the average value of the plurality of displacement values), or the torque Mz may be detected based on the detection results of one displacement sensor 2 among the plurality of displacement sensors 2. Torque Mz may be detected based on the result. Further, the plurality of displacement sensors 2 may be arranged in any manner. For example, one or more displacement sensors 2 may be provided for each space partitioned by two third structures 13.

The displacement sensor 2 includes a reference part 21 and a deformable part 22. The reference portion 21 and the deformable portion 22 are each plate-shaped members. The displacement sensor 2 detects the torque Mz based on the amount of change in the distance between the reference part 21 and the deformable part 22. When torque Mz is not applied, each deformed portion 22 of the two displacement sensors 2 is in contact with the tip of the protrusion 14 . Each of the reference parts 21 of the two displacement sensors 2 is provided at a position opposite to the protruding part 14 with respect to the deformed part 22, and the corresponding deformed part 22 and the widest surface of the plate shape have the largest area. are arranged to face each other.

When torque Mz is applied, the first structure 11 provided with the protrusion 14 rotates relative to the second structure 12, and the tip of the protrusion 14 deforms the deformed part 22 of one displacement sensor 2. The deformable portion 22 is deformed. On the other hand, the reference part 21 does not deform even if the torque Mz is applied, and its position in the second structure 12 does not change. The distance between the reference portion 21 and the deformable portion 22 changes as the deformable portion 22 deforms due to the application of the torque Mz.

For example, the displacement sensor 2 is a capacitive sensor. The reference portion 21 and the deformed portion 22 are electrically conductive conductors. The reference part 21 is electrically connected to the deformable part 22. As the distance between the reference part 21 and the deformed part 22 changes, the capacitance between the reference part 21 and the deformed part 22 changes. Torque sensor 1 detects torque Mz based on the amount of change in capacitance measured by displacement sensor 2.

Here, we have explained that the displacement sensor 2 uses a capacitance type, but any type of sensor can be used as long as it can measure the physical quantity that indicates the amount of change in the distance between the reference part 21 and the deformed part 22. May be used. For example, the displacement sensor 2 may be of an optical type or a magnetic type. Further, when changing the measurement method, the mounting method of the displacement sensor 2 can be changed in accordance with the changed measurement method. For example, when an optical sensor is employed, a light emitting element and a light receiving element may be provided to optically measure the distance between the reference part 21 and the deformed part 22. Further, when a magnetic sensor is employed, a measurement terminal for magnetic measurement may be attached to either the reference portion 21 or the deformable portion 22.

Note that the displacement sensor 2 is not limited to what is described here, and may have any configuration or arrangement. For example, in the displacement sensor 2, a member corresponding to the reference portion 21 may be deformed by application of the torque Mz. Further, as long as the displacement sensor 2 can detect displacement, the reference portion 21 and the deformable portion 22 do not need to be plate-shaped.

FIG. 2 is a configuration diagram showing the configuration of the arithmetic processing section 3 according to this embodiment.
The arithmetic processing unit 3 is a computer such as a microcomputer. The arithmetic processing unit 3 realizes various functions through arithmetic processing executed by a program or the like. The calculation processing section 3 includes a torque calculation section 31.

The detection signal Sd detected by the displacement sensor 2 is input to the torque calculation section 31 . The detection signal Sd is an electrical signal that detects the capacitance indicating the distance between the reference portion 21 and the deformable portion 22. The torque calculation unit 31 calculates torque Mz based on the detected capacitance. That is, the torque calculation section 31 calculates the torque Mz based on the distance between the reference section 21 and the deformation section 22. The torque Mz calculated by the torque calculation unit 31 is output as a detection result by the torque sensor 1.

With reference to FIG. 3, a method for detecting torque Mz by the torque sensor 1 according to the present embodiment will be described. Here, a method of detecting torque Mz applied clockwise by one displacement sensor 2 will be described, but a method of detecting torque Mz applied counterclockwise by the other displacement sensor 2 will also be described. The same is true.

The protrusion 14 shown by a solid line shows an initial state before torque Mz is applied. The protrusion 14 shown by a dotted line shows the state after the torque Mz is applied. The deformed portion 22 shown by a solid line shows an initial state before torque Mz is applied. The deformed portion 22 shown by the dotted line shows the state after the torque Mz is applied. Further, a center line L1 passing through the center of the protrusion 14 in the width direction represents the inclination of the protrusion 14.

In the initial state, the tip of the protrusion 14 is slightly in contact with the deformed portion 22 of the displacement sensor 2. When torque Mz is applied, the protrusion 14 fixed to the first structure 11 rotates relative to the second structure 12. As a result, the protrusion 14 is tilted at an angle θ.

When the protrusion 14 is tilted, the deformable part 22 that is in contact with the protrusion 14 is pushed by the protrusion 14 and deforms so as to approach the reference part 21 of the displacement sensor 2 . As a result, the distance between the reference portion 21 and the deformed portion 22 changes. Specifically, the distance between the reference portion 21 and the deformable portion 22 decreases from the distance d1 to the distance d2 before and after applying the torque Mz. Therefore, by reducing the distance between the reference part 21 and the deformable part 22, the capacitance between the reference part 21 and the deformable part 22 increases.

From this, the stronger the torque Mz, the shorter the distance between the reference portion 21 and the deformable portion 22, and the more the capacitance detected by the displacement sensor 2 increases. In this way, the torque Mz can be measured based on the capacitance detected by the displacement sensor 2.

According to this embodiment, the protrusion 14 is provided on the first structure 11, the displacement sensor 2 is provided on the second structure 12, and the displacement sensor 2 is moved by the rotation that generates the torque Mz. Detect displacement. Thereby, the torque sensor 1 can detect torque Mz based on the displacement detected by the displacement sensor 2. Therefore, the torque sensor 1 can increase the detection accuracy of the displacement torque Mz by detecting the displacement with the displacement sensor 2 in the limited space between the first structure 11 and the second structure 12. .

(Second embodiment)
FIG. 4 is a top view showing the configuration of a torque sensor 1A according to a second embodiment of the present invention.

The torque sensor 1A has a protrusion 14A and two displacement sensors 2A instead of the protrusion 14 and the two displacement sensors 2 in the torque sensor 1 according to the first embodiment shown in FIG. Other points are the same as the torque sensor 1 according to the first embodiment.

The protrusion 14A is provided on the outer peripheral side of the second structure 12 so as to protrude toward the first structure 11. In other respects, the protrusion 14A is similar to the protrusion 14 according to the first embodiment.

The two displacement sensors 2A are provided on the inner peripheral side of the first structure 11 such that the tip of the projection 14A is located between the two displacement sensors 2A. In other respects, the displacement sensor 2A is the same as the two displacement sensors 2A according to the first embodiment.

According to this embodiment, by providing the protrusion 14A on the second structure 12 and providing the displacement sensor 2A on the first structure 11, the same effects as in the first embodiment can be obtained.

It is noted that additional advantages and modifications may readily occur to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

DESCRIPTION OF SYMBOLS 1... Torque sensor, 2... Displacement sensor, 3... Arithmetic processing unit, 11... First structure, 12... Second structure, 13... Third structure, 14... Protrusion.

Claims (6)

a first structure formed in a ring shape;
a second structure formed in a ring shape smaller than the first structure and disposed on the inner peripheral side of the first structure;
a protrusion provided on the first structure and protruding toward the second structure;
A distance between two members that is provided in the second structure and that changes when the first structure rotates relative to the second structure due to application of torque and comes into contact with the protrusion. a sensor that detects a physical quantity indicating
A torque sensor comprising: torque detection means for detecting the torque based on a physical quantity detected by the sensor. a first structure formed in a ring shape;
a second structure formed in a ring shape smaller than the first structure and disposed on the inner peripheral side of the first structure;
a protrusion provided on the second structure so as to protrude toward the first structure;
A distance between two members that are provided in the first structure and that changes when the first structure rotates relative to the second structure due to application of torque and comes into contact with the protrusion. a sensor that detects a physical quantity indicating
A torque sensor comprising: torque detection means for detecting the torque based on a physical quantity detected by the sensor. 3. The torque sensor according to claim 1, further comprising two sensors for separately detecting two torques having different rotational directions. 3. The torque sensor according to claim 1, wherein the sensor detects capacitance indicating a distance between the two members. 3. The torque sensor according to claim 1, wherein the sensor optically detects the distance between the two members. 3. The torque sensor according to claim 1, wherein the sensor magnetically detects the distance between the two members.

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