CN117529641A

CN117529641A - Sensor for detecting a position of a body

Info

Publication number: CN117529641A
Application number: CN202280043948.8A
Authority: CN
Inventors: 大竹亚里沙
Original assignee: Nideco Zhibo Electronics Co ltd
Current assignee: Nideco Zhibo Electronics Co ltd
Priority date: 2021-08-03
Filing date: 2022-06-29
Publication date: 2024-02-06
Also published as: JP2023022592A; WO2023013316A1

Abstract

The sensor (10) comprises: a first structure (11) formed in a ring shape; a second structure (12) formed in a ring shape on the inner peripheral side of the first structure (11); a strain body (20) provided between the first structure (11) and the second structure (12); and a plurality of sensor elements (21 a-21d,22a-22 d) that constitute a first series detection circuit and a second series detection circuit that are doubled, are arranged on the surface of one side of the strain body (20) in a line-symmetrical manner, and detect the strain.

Description

Sensor for detecting a position of a body

Technical Field

Embodiments of the present invention relate to a sensor that detects force.

Background

A torque sensor is known in which a bridge circuit including a plurality of strain sensors detects a force transmitted between a first structure and a second structure. For example, a torque sensor that detects an abnormality based on a difference between output voltages of two bridge circuits including a plurality of strain sensors is disclosed (for example, refer to patent document 1).

However, when a detection circuit (bridge circuit or the like) using strain sensors is duplicated, it is physically impossible to dispose two strain sensors at the same position. Therefore, the detection accuracy of each detection circuit varies depending on the arrangement of the strain sensors of the doubled detection circuit. In this way, the detection accuracy of the doubled detection circuits is different, and the doubled detection circuits are not ideal as sensors.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2018-132313

Disclosure of Invention

An object of the present embodiment is to provide a sensor that reduces a difference in detection accuracy between the respective double detection circuits.

The sensor according to an embodiment of the present invention includes: a first structure formed in a ring shape; a second structure formed in a ring shape on an inner peripheral side of the first structure; a strain body provided between the first structure and the second structure; and a plurality of sensor elements that constitute a first series detection circuit and a second series detection circuit that are duplicated, are arranged on one side surface of the strain body in a line-symmetrical manner, and detect the strain.

Drawings

Fig. 1 is an enlarged perspective view of the vicinity of a sensor portion of a torque sensor according to a first embodiment.

Fig. 2 is a plan view showing the structure of the torque sensor of the first embodiment.

Fig. 3 is a plan view showing a structure of a sensor portion provided with 1 terminal portion of the first embodiment.

Fig. 4 is a plan view showing a structure of a sensor portion provided with 2 terminal portions of the first embodiment.

Fig. 5 is a front view showing an installation state of the torque sensor of the first embodiment.

FIG. 6 is a cross-sectional view of the torque sensor mounting plate shown in FIG. 5 taken along line A-A.

Fig. 7 is a simplified diagram showing a state of the torque sensor when an external load is generated on the torque sensor mounting plate of the first embodiment.

Fig. 8 is a plan view showing the structure of the sensor unit of the second embodiment.

Fig. 9 is a plan view showing the structure of the sensor unit of the third embodiment.

Detailed Description

(first embodiment)

Fig. 1 is an enlarged perspective view of the vicinity of a sensor portion 14 of a torque sensor 10 according to the first embodiment. Fig. 2 is a plan view showing the structure of the torque sensor 10 of the present embodiment. In the drawings, the same parts are given the same symbols.

The torque sensor 10 is not limited to the description herein, and may be modified to have various shapes and configurations. The torque sensor 10 may be a sensor of another name such as a force sensor as long as it is a sensor that detects at least torque (z-axis torque Mz). For example, the force sensor detects the respective translational forces Fx, fy, fz and moments Mx, my, mz of the orthogonal three axes (x-axis, y-axis, z-axis) shown in fig. 2.

The torque sensor 10 includes a first structural body 11, a second structural body 12, a plurality of third structural bodies 13, a plurality of sensor portions 14, a housing 15, and a cable 16.

The first structure 11, the second structure 12, and the third structure 13 are integrally formed as one elastic body. The first structure 11, the second structure 12, and the third structure 13 are made of a metal such as stainless steel, but a material other than metal (such as a resin) may be used if the material has sufficient mechanical strength against a force such as an applied torque.

The first structure 11 and the second structure 12 are formed in a ring shape. The diameter of the second structure 12 is smaller than the diameter of the first structure 11. The second structure 12 is disposed on the inner peripheral side on a circle concentric with the first structure 11. The plurality of third structures 13 are arranged radially and are provided as beams connecting the first structure 11 and the second structure 12. The third structure 13 may be provided in any number.

The thickness (length in the z-axis direction) of the third structure 13 is smaller than the thicknesses of the first structure 11 and the second structure 12. Specifically, the thickness of the third structure 13 is inclined so as to be thinner from the both end portions connected to the first structure 11 or the second structure 12 toward the center, and the center portion is a uniform thickness (plane). The third structure 13 is made to have a thickness (length in the z-axis direction) longer than a width (length in the circumferential direction) so that torque can be easily detected, but the thickness and width of the third structure 13 may be arbitrarily determined.

The housing 15 is provided so as to cover a hollow portion provided in a central portion of the second structural body 12. The hollow portion is provided with a data processing circuit for processing data detected by each sensor portion 14. The data processing circuit is electrically connected to each sensor unit 14 via a flexible substrate (flexible printed circuit board). The data processing circuit is supplied with power via the cable 16, and outputs the sensor signal after data processing to the outside.

The sensor unit 14 detects strain generated by the relative movement between the first structure 11 and the second structure 12. The data indicating the strain detected by the sensor unit 14 is transmitted as an electrical signal to a data processing circuit. The data processing circuit detects the applied force such as torque based on the strain detected by the sensor unit 14. Here, the structure in which 4 sensor portions 14 are provided at equal intervals (90 degree intervals) in the circumferential direction is shown, but other numbers of sensor portions 14 may be provided.

The sensor unit 14 includes a strain body 20, 4 a-series sensor elements 21a, 21B, 21c, 21d, and 4B-series sensor elements 22a, 22B, 22c, 22d.

The sensor portion 14 is provided so as to span between the first structure 11 and the second structure 12. Both ends of the sensor portion 14 are fixed to the first structure 11 and the second structure 12, respectively. In order to fix both ends of the sensor portion 14, the first structure 11 and the second structure 12 are formed with recesses 11a and 12a having a thickness thinner than the other portions. For example, covers for protecting the sensor portion 14 from external factors, such as waterproofing and dust proofing, are fitted into the concave portions 11a, 12a of the upper surface of the sensor portion 14. The lower surface of the sensor portion 14 may be provided with a cover in the same manner.

The sensor portion 14 is mounted by fixing both ends of the strain body 20 to the first structure 11 and the second structure 12. Specifically, fixing plates 31 are disposed so as to press both ends of the strain body 20 from the upper surface, and both ends of the strain body 20 are fixed to the first structure 11 and the second structure 12 with screws 32 together with the fixing plates 31. The sensor unit 14 may be mounted.

The a-series sensor elements 21a to 21d and the B-series sensor elements 22a to 22d are arranged between the first structure 11 and the second structure 12 on the upper surface of the strain body 20. The A-series sensor elements 21a to 21d and the B-series sensor elements 22a to 22d are wired to form an A-series detection circuit and a B-series detection circuit, respectively. The two detection circuits are double detection circuits for detecting torque and the like, and each of the two detection circuits independently detects torque and the like. The torque sensor 10 outputs torque or the like as a detection result based on detection data of the two detection circuits. The torque sensor 10 may determine the torque or the like as the detection result based on the detection data of one of the two detection circuits.

Here, the a-series sensor elements 21a to 21d and the B-series sensor elements 22a to 22d are assumed to be strain gauges, and the detection circuit is assumed to be a full bridge circuit, but the present invention is not limited thereto. For example, each system of detection circuits may be a bridge circuit composed of 2 strain gauges provided on the strain body 20 and a reference resistor provided at a portion (for example, a data processing circuit provided on the second structure 12) which is not substantially deformed by the application of torque or the like. Specifically, the bridge circuit may be constituted by 2 sensor elements selected arbitrarily from the 4 sensor elements 21a to 21d,22a to 22d of each system, and 2 reference resistors provided in the data processing circuit. The latter embodiment is not limited to the full bridge circuit, and may be configured as a similar bridge circuit.

With reference to fig. 3 and 4, 2 examples will be described as the configuration of the sensor unit 14. Fig. 3 is a plan view showing a structure of a sensor unit 14a provided with a terminal portion T1 that integrates the terminals of the sensor elements 21a to 21d and 22a to 22d. Fig. 4 is a plan view showing a structure of a sensor portion 14b provided with terminal portions Ta and Tb in which the terminals of the sensor elements 21a to 21d and 22a to 22d are respectively gathered at two positions. The wiring of each sensor element 21a to 21d,22a to 22d is not limited to the configuration described herein. For example, 3 or more terminal portions of the sensor elements 21a to 21d and 22a to 22d may be provided.

The upper and lower surfaces of the strain body 20 are rectangular plate-shaped. The upper and lower surfaces of the sensor elements 21a to 21d and 22a to 22d are rectangular plate-shaped. The sensor elements 21a to 21d and 22a to 22d in the strain body 20 of each sensor portion 14a, 14b are arranged substantially identically. The a-series sensor elements 21a to 21d are arranged on the first structure 11 side (left side in the drawing) of the strain body 20. The B-system sensor elements 22a to 22d are arranged on the second structure 12 side (right side in the drawing) of the strain body 20.

The first a-series sensor element 21a and the second a-series sensor element 21b of the first group of the 4 a-series sensor elements 21a to 21d are disposed close to each other within a non-contact range so as to maintain an electrical insulation distance. The a-series sensor elements 21a and 21b of the first group are arranged obliquely to the longitudinal direction of the strain body 20 so that the end portions on the first structure 11 side face outward in substantially the same direction.

The third a-series sensor element 21c and the fourth a-series sensor element 21d of the second group of the 4 a-series sensor elements 21a to 21d are disposed in proximity within a non-contact range so as to be oriented in substantially the same direction and so as to maintain an electrical insulation distance. The second group of a-type sensor elements 21c and 21d are arranged so as to be line-symmetrical to the first group of a-type sensor elements 21a and 21b with respect to a center line that bisects the strain body 20 in the longitudinal direction.

The 4B-series sensor elements 22a to 22d are arranged so as to be line-symmetrical to the 4 a-series sensor elements 21a to 21d with respect to a center line that bisects the strain body 20 in the short-side direction (direction perpendicular to the long-side direction).

The terminal portion T1 shown in fig. 3 is arranged at the center of the strain body 20 in the longitudinal direction, and is configured such that the terminals are arranged adjacently in the short-side direction. Each of the terminals of the a-series sensor elements 21a to 21d is electrically connected to a terminal located at the center of the terminal portion T1 through two wires W1. Each of the terminals of the B-system sensor elements 22a to 22d is electrically connected to the terminals located at both ends of the terminal portion T1 through two wires W1. Each of the terminals of the sensor elements 21a to 21d and 22a to 22d may be connected to any of the terminals of the terminal portion T1.

The terminal portions Ta and Tb shown in fig. 4 are configured to divide the terminal portion T1 shown in fig. 3 into two. Each terminal of the a-series sensor elements 21a to 21d is electrically connected to the a-series terminal portion Ta through two wirings Wa. Each terminal of the B-series sensor elements 22a to 22d is electrically connected to the B-series terminal portion Tb through two wirings Wb.

The state after the torque sensor 10 is mounted will be described with reference to fig. 5 and 6. Fig. 5 is a front view showing an installation state of the torque sensor 10. Fig. 6 is a cross-sectional view of the torque sensor mounting plate 41 shown in fig. 5 cut by line A-A. In fig. 6, the adapter 42, the decelerator 43, and the motor 44 are simply shown.

The torque sensor 10 is mounted on a torque sensor mounting plate 41. Thereby, the first structural body 11 of the torque sensor 10 is fixed to the torque sensor mounting plate 41. The torque sensor mounting plate 41 is a member mounted on a structure to which torque or the like is applied.

The second structure 12 of the torque sensor 10 is fixed to a speed reducer 43 coupled to a motor 44 via an adapter 42. By driving the motor 44, the torque output from the motor 44 is applied to the torque sensor mounting plate 41 via the decelerator 43, the adapter 42, and the torque sensor 10. Thereby, the torque sensor mounting plate 41 and the structure to which the torque sensor mounting plate 41 is attached are operated by the torque output from the motor 44.

The second structure 12 of the torque sensor 10 may be mounted on the side to which torque is applied (the torque sensor mounting plate 41, etc.), and the first structure 11 of the torque sensor 10 may be mounted on the side to which torque is applied (the motor 44, etc.).

With reference to fig. 5 and 7, a case will be described in which an external load (load or the like) Fw is generated on the torque sensor mounting plate 41. Fig. 7 is a simplified diagram showing a state of the torque sensor 10 when an external load is generated on the torque sensor mounting plate 41. Fig. 5 and 7 show two arrangement patterns P1 and P2 of 4 sensor units 14, and the sensor unit 14 is mounted using either one of the two arrangement patterns P1 and P2. The sensor unit 14 is not limited to the two arrangement patterns P1 and P2, and other arrangement patterns may be used.

As shown in fig. 7, when a downward external load Fw such as an arrow is generated on the torque sensor mounting plate 41, tensile stress is generated on the upper side of the torque sensor mounting plate 41, and compressive stress is generated on the lower side of the torque sensor mounting plate 41.

Due to the deformation of the torque sensor mounting plate 41, the elastic bodies (the first structural body 11, the second structural body 12, and the third structural body 13) of the torque sensor 10 are deformed from the circular shape shown by the broken line to the elliptical shape shown by the solid line. If the deformed elastic body is elliptical, the elastic body is stretched in the major axis direction and compressed in the minor axis direction.

Due to the deformation of the elastic body, each sensor portion 14 of the arbitrary arrangement patterns P1, P2 is deformed from a rectangular shape shown by a broken line to a quadrangular shape shown by a solid line. In this way, when the external load Fw is generated, the stress applied to the sensor portion 14 by the external load Fw differs between the arrangement patterns P1 and P2 at each arrangement position.

In the torque sensor 10, a-type sensor elements 21a to 21d and B-type sensor elements 22a to 22d, which constitute a double-type detection circuit and a double-type detection circuit, respectively, are provided in each sensor portion 14. Therefore, even when the stress applied to the sensor portions 14 is different, the corresponding detection accuracy of the detection circuits of the respective systems is substantially the same.

In contrast, unlike the torque sensor 10 of the present embodiment, a case is considered in which the sensor portion 14 in which only the a-type detection circuit is provided is arranged in the arrangement pattern P1, and the sensor portion 14 in which only the B-type detection circuit is provided is arranged in the arrangement pattern P2, and the double detection circuit is provided.

When the external load Fw is not generated at all and the ideal torque is applied to the torque sensor 10, the stress applied to the sensor portions 14 of the arrangement patterns P1 and P2 is substantially the same. That is, the strain body 20 of each sensor portion 14 is deformed in substantially the same manner. Therefore, since the strains detected by the respective systems are substantially the same, the detection accuracy of the two detection circuits which are duplicated hardly varies.

On the other hand, when the external load Fw is generated, even if the torque sensor 10 is applied with a desired torque, the stress received by the sensor portion 14 varies due to the arrangement position of the sensor portion 14 as described above. That is, the strain bodies 20 of the sensor units 14 are deformed differently. Therefore, since the strains detected by the two systems are different, there is a possibility that the detection accuracy of the two detection circuits may be greatly different. For example, when a function of detecting an abnormality from a difference between the two detection circuits is provided, even if a normal torque or the like is applied, an unexpected abnormality may be detected.

According to the present embodiment, by providing the sensor elements 21a to 21d and 22a to 22d of each of the two detection circuits that are duplicated in the same sensor unit 14, even when the external load Fw is generated, the difference in detection accuracy of the two detection circuits that are duplicated can be suppressed.

Further, by providing the a-type sensor elements 21a to 21d and the B-type sensor elements 22a to 22d on the surface (front surface or back surface) of one strain body 20 in line symmetry, the data indicating strain detected by each of the a-type detection circuit and the B-type detection circuit can be made to approach each other. The a-series sensor elements 21a to 21d and the B-series sensor elements 22a to 22d may be provided so as to be line-symmetrical with respect to a center line that bisects the strain body 20 in the longitudinal direction.

In this case, all of the sensor elements 21a to 21d and 22a to 22d are provided on the front surface of the strain body 20, but may be provided on the rear surface of the strain body 20.

(second embodiment)

Fig. 8 is a plan view showing the structure of the sensor unit 14A according to the second embodiment.

The sensor unit 14A is a sensor unit in which the arrangement of the sensor elements 21a to 21d,22a to 22d, wiring thereof, and the like are changed in the sensor unit 14A of the first embodiment shown in fig. 3. Otherwise, the torque sensor 10 of the first embodiment is the same.

The sensor unit 14A has one terminal portion T1, similar to the sensor unit 14A shown in fig. 3. The terminal portion T1 is arranged at the center of the strain body 20 in the longitudinal direction, and is configured such that the terminals are arranged adjacent to each other in the short-side direction. Each of the terminals of the a-series sensor elements 21A to 21d is electrically connected to the terminals located at both ends of the terminal portion T1 through two wires W1A. Each of the terminals of the B-series sensor elements 22a to 22d is electrically connected to a terminal located at the center of the terminal portion T1 through two wires W1A. Each of the terminals of the sensor elements 21a to 21d and 22a to 22d may be connected to any of the terminals of the terminal portion T1.

The first a-system sensor element 21a is disposed on the first structure 11 side of the strain body 20 so as to be inclined with respect to the longitudinal direction of the strain body 20 such that the end on the first structure 11 side faces outward. The fourth a-system sensor element 21d is disposed on the first structure 11 side of the strain body 20 so as to be line-symmetrical to the first a-system sensor element 21a with respect to a center line that bisects the strain body 20 in the longitudinal direction.

The second a-type sensor element 21b and the third a-type sensor element 21c are arranged so as to be line-symmetrical to the first a-type sensor element 21a and the fourth a-type sensor element 21d, respectively, with respect to a center line that bisects the strain body 20 in the short-side direction.

The B-series sensor elements 22a to 22d are disposed in proximity to the corresponding a-series sensor elements 21a to 21d in a non-contact range so as to maintain an electric insulation distance therebetween, and are disposed in substantially the same direction. For example, the correspondence between the a-series sensor elements 21a to 21d and the B-series sensor elements 22a to 22d is determined by the circuit positional relationship between the a-series detection circuit and the B-series detection circuit.

Accordingly, the arrangement of the sensor elements 21a to 21d and 22a to 22d in the sensor unit 14A is an arrangement in which the second a-type sensor element 21B and the third a-type sensor element 21c are respectively shifted from the first B-type sensor element 22a and the fourth B-type sensor element 22d in the sensor unit 14A shown in fig. 3.

According to the present embodiment, the sensor elements 21a to 21d and 22a to 22d corresponding to each other are arranged close to each other between the two detection circuits for doubling and are arranged on the strain body 20, whereby the same operational effects as those of the first embodiment can be obtained.

(third embodiment)

Fig. 9 is a plan view showing the structure of the sensor unit 14B according to the third embodiment.

The sensor unit 14B is a sensor unit in which the arrangement of the a-system sensor elements 21a to 21d, wiring thereof, and the like are changed in the sensor unit 14a of the first embodiment shown in fig. 3. Otherwise, the torque sensor 10 of the first embodiment is the same.

The arrangement and wiring of the B-series sensor elements 22a to 22d in the sensor unit 14B are the same as those of the sensor unit 14a shown in fig. 3. The a-series sensor elements 21a to 21d and the B-series sensor elements 22a to 22d are arranged on the second structure 12 side of the strain body 20.

The sensor unit 14B has one terminal portion T1, similar to the sensor unit 14a shown in fig. 3. The terminal portion T1 is arranged at the center of the strain body 20 in the longitudinal direction, and is configured such that the terminals are arranged adjacently in the short-side direction. Each of the terminals of the a-series sensor elements 21a to 21d is electrically connected to a terminal located at the center of the terminal portion T1 through two wires W1B. Each of the terminals of the B-system sensor elements 22a to 22d is electrically connected to the terminals located at both ends of the terminal portion T1 through two wires W1B. Each of the terminals of the sensor elements 21a to 21d and 22a to 22d may be connected to any of the terminals of the terminal portion T1.

The first B-system sensor element 21a is disposed close to the second B-system sensor element 22B within a range not in contact with the second B-system sensor element 22B so as to maintain an electrically insulating distance at a position closer to the inner side of the strain body 20 than the second B-system sensor element 22B. The first a-system sensor element 21a is disposed obliquely to the longitudinal direction of the strain body 20 so that the end on the second structure 12 side faces outward in the substantially same direction as the second B-system sensor element 22B.

The second a-system sensor element 21b is disposed close to the first a-system sensor element 21a within a range not in contact with the first a-system sensor element 21a so as to maintain an electrical insulation distance at a position closer to the inner side of the strain body 20 than the first a-system sensor element 21 a. The second a-system sensor element 21b is disposed obliquely to the longitudinal direction of the strain body 20 so that the end on the second structure 12 side faces outward in the same direction as the first a-system sensor element 21 a.

The third a-type sensor element 21c and the fourth a-type sensor element 21d are arranged so as to be line-symmetrical to the second a-type sensor element 21b and the first a-type sensor element 21a, respectively, with respect to a center line that bisects the strain body 20 in the longitudinal direction.

That is, the fourth a-type sensor element 21d is disposed close to the third B-type sensor element 22c within a range not in contact with the third B-type sensor element 22c so as to maintain an electrical insulation distance at a position closer to the inner side of the strain body 20 than the third B-type sensor element 22 c. The third a-system sensor element 21c is disposed close to the fourth a-system sensor element 21d within a range not in contact with the fourth a-system sensor element 21d so as to maintain an electrical insulation distance at a position closer to the inner side of the strain body 20 than the fourth a-system sensor element 21 d.

According to the present embodiment, by disposing all of the sensor elements 21a to 21d and 22a to 22d of the two detection circuits on the second structure 12 side of the strain body 20, the same operational effects as those of the first embodiment can be obtained.

The sensor elements 21a to 21d and 22a to 22d may be arranged on the first structure 11 side of the strain body 20 so as to be line-symmetrical to the arrangement shown in fig. 9. In this way, the same operational effects as those of the first embodiment can be obtained.

The present invention is not limited to the above embodiments, and in the implementation stage, the constituent elements may be modified and embodied within a range not departing from the gist thereof. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some of the constituent elements may be deleted from all of the constituent elements shown in the embodiment. In addition, the constituent elements of the different embodiments may be appropriately combined.

Claims

1. A sensor, comprising:

a first structure formed in a ring shape;

a second structure formed in a ring shape on an inner peripheral side of the first structure;

a strain body provided between the first structure and the second structure; and

and a plurality of sensor elements forming a first series detection circuit and a second series detection circuit which are duplicated, and arranged on one side surface of the strain body in a line symmetrical manner, and detecting the strain.

2. The sensor of claim 1, wherein:

the plurality of first sensor elements of the first series detection circuit are arranged line symmetrically,

the plurality of second sensor elements of the second series detection circuit are arranged line symmetrically.

3. The sensor of claim 2, wherein:

the plurality of first sensor elements are each disposed in close proximity to the other first sensor elements,

the plurality of second sensor elements are each disposed in close proximity to the other second sensor elements.

4. The sensor of claim 1, wherein:

the plurality of first sensor elements of the first series detection circuit and the plurality of second sensor elements of the second series detection circuit are arranged line symmetrically.

5. The sensor of claim 4, wherein:

the plurality of first sensor elements and the plurality of second sensor elements are arranged in proximity in a respective corresponding manner.