A component to be measured with a strain gauge attached, and a robot

Abstract

To provide a mounting structure for a strain gauge which can improve durability and can be applied to a larger number of configurations.SOLUTION: A structure for mounting a strain gauge (10) on a portion (91) to be measured, the strain gauge comprising a base member (11) in a film form, a resistance element (20) provided on the base member, a first wiring line (30) provided on the base member and connected to the resistance element, a terminal (40) provided on the base member and connected to the first wiring line, and a second wiring line (50) connected to the terminal. Of the base member, a first portion (P1) on which the resistance element is provided is adhered to the portion to be measured, while a second portion (P2) on which the terminal is provided is not adhered to another member (90).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to attaching a strain gauge The member to be measured thereto.

Background Art

[0002] Conventionally, in this type of strain gauge mounting structure, a flat surface portion is provided where the mutually continuous end surfaces of an annular diaphragm and an annular boss integrally formed on the outer peripheral edge of the diaphragm are located on the same plane. A resistance wire of the strain gauge is attached to the flat surface portion on the diaphragm side, and a terminal for connecting the resistance wire to a lead wire is attached to the flat surface portion on the boss side (see Patent Document

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the strain gauge mounting structure described in Patent Document 1 can only be applied to a configuration in which the measured portion (diaphragm) and the portion without elastic deformation (boss) are adjacent and flat, and the applicable configuration is limited.

[0005] The present invention has been made to solve the above problems, and its main object is to provide a strain gauge that can improve durability and be applicable to more configurations. The member to be measured to which the attachment is attached. ​[Means for solving the problem]

[0006] The first means to solve the above problem is, A structure for attaching a strain gauge to the part to be measured, The strain gauge comprises a film-like or plate-like base member, a resistor provided on the base member, a first wiring provided on the base member and connected to the resistor, a terminal provided on the base member and connected to the first wiring, and a second wiring connected to the terminal. The first portion of the base material on which the resistor is provided is adhered to the portion to be measured. The second portion of the base material on which the terminal is provided is not bonded to any other material.

[0007] According to the above configuration, the strain gauge comprises a base member, a resistor provided on the base member, a first wiring provided on the base member and connected to the resistor, a terminal provided on the base member and connected to the first wiring, and a second wiring connected to the terminal. The first portion of the base member on which the resistor is provided is bonded to the part to be measured. Therefore, the resistor provided on the first portion can be deformed in accordance with the strain of the part to be measured. Then, by measuring the resistance value of the resistor via the second wiring connected to the terminal, the strain of the part to be measured can be measured based on the change in the resistance value of the resistor. In addition, each component of the strain gauge can be combined into a single base member, making the handling of the strain gauge easier.

[0008] On the other hand, the second portion of the base member on which the terminal is provided is not bonded to other members. Therefore, even if distortion occurs in the part being measured, distortion of the terminal provided in the second portion can be suppressed. Consequently, repeated stress on the terminal can be suppressed, and damage to the connection between the terminal and the second wiring can be suppressed. Furthermore, since it is not necessary to bond the second portion to the part adjacent to the part being measured, the configuration of the part adjacent to the part being measured can be set more freely. Therefore, durability can be improved, and a strain gauge mounting structure that can be applied to a wider range of configurations can be provided.

[0009] In the second means, the first wiring extends from the resistor in a predetermined direction, and the terminal extends from the first wiring, wherein the length of the first wiring is longer than the length of the terminal in the predetermined direction.

[0010] According to the above configuration, the first wiring extends from the resistor in a predetermined direction, and the terminal extends from the first wiring. Therefore, the first wiring and the terminal can be drawn out from the resistor in a predetermined direction. In the predetermined direction, the length of the first wiring is longer than the length of the terminal. Therefore, the portion of the base material on which the first wiring is provided (hereinafter referred to as the "third portion") can suppress the transmission of strain generated in the part under measurement to the second portion via the base material.

[0011] In the third means, in the predetermined direction, the length of the resistor is longer than the length of the terminal, and in the predetermined direction, the length of the first wiring is longer than the length of the resistor.

[0012] According to the above configuration, in the predetermined direction, the length of the first wiring is longer than the length of the resistor (> terminal length). Therefore, the third part can effectively suppress the transmission of strain generated in the part under measurement to the second part via the base material. Furthermore, when the first part is bonded to the part under measurement with adhesive, even if the adhesive protrudes beyond the first part, the third part can prevent the adhesive from reaching the second part, and consequently from bonding the second part to other materials.

[0013] In the fourth method, the member to be measured, which constitutes the portion to be measured, extends from the portion to be measured to a position opposite the second portion, and the second portion and the member to be measured are in contact. Even with this configuration, since the second portion and the member to be measured (other members) are not bonded together, the same effects as the first method can be achieved.

[0014] Furthermore, in the fifth means, a predetermined space is formed between the member to be measured, which constitutes the portion to be measured, and the second portion. With this configuration, the predetermined space can be effectively utilized.

[0015] If a terminal is provided on the surface of the base material facing the part to be measured, the part to be measured may get in the way when connecting the second wiring to the terminal.

[0016] In this regard, assuming the fifth means, the sixth means provides the terminal on the surface of the base member facing the portion to be measured. With this configuration, since the predetermined space is formed between the portion to be measured and the second portion on which the terminal is provided, it is possible to suppress the portion to be measured from getting in the way when connecting the second wiring to the terminal.

[0017] Specifically, on the premise of any one of the first to sixth means, a configuration such as the seventh means, in which the terminal and the second wiring are connected by solder, can be adopted. According to such a configuration, since it is premised on a configuration capable of suppressing the repeated action of stress on the terminal, it is possible to suppress the occurrence of cracks in the solder or cracks at the boundary between the terminal and the solder.

[0018] Specifically, on the premise of any one of the first to seventh means, a configuration such as a robot having the strain gauge mounting structure described in any one of the first to seventh means can be adopted.

Brief Description of Drawings

[0019] [Figure 1] Plan view of the strain gauge mounting structure. [Figure 2] Side view of the strain gauge mounting structure. [Figure 3] Plan view of a comparative example of the strain gauge mounting structure. [Figure 4] Side view of a comparative example of the strain gauge mounting structure. [Figure 5] Side view of a modified example of the strain gauge mounting structure. [Figure 6] Side view of another modified example of the strain gauge mounting structure. [Figure 7] Side view of another modified example of the strain gauge mounting structure.

Mode for Carrying Out the Invention

[0020] Hereinafter, an embodiment embodied in the mounting structure of a strain gauge provided in a joint of a robot will be described with reference to the drawings. The robot controller (control unit) measures the resistance value of the strain gauge and measures the strain of the measured portion based on the change in the resistance value. The controller calculates the torque acting on the joint based on the measured strain. That is, the strain gauge is used as a torque sensor that detects torque. Since the method of calculating torque in this way is well known, a detailed description will be omitted.

[0021] As shown in Figures 1 and 2, the strain gauge 10 measures the strain of a portion 91 of the member 90 to be measured. The strain gauge 10 includes a film 11, a resistor 20, printed wiring 30, printed terminals 40, wires 50, solder 55, etc. Note that in Figure 2, the resistor 20, printed wiring 30, and printed terminals 40 are not shown.

[0022] The film 11 (base material) is formed in a rectangular film shape using, for example, polyimide (insulating resin).

[0023] The resistor 20 is formed (provided) on the upper surface (one side) of the film 11 in a predetermined pattern (shape) using a resistive material. The resistor 20 is formed at one end of the film 11 in the longitudinal direction.

[0024] The printed circuit board 30 (first circuit board) is formed (provided) in a straight line on the upper surface of the film 11 using a resistive material or a conductive material. The printed circuit board 30 is connected to the resistor 20 and extends from the resistor 20 in a predetermined direction from one side to the other in the longitudinal direction of the film 11.

[0025] The printed terminal 40 (terminal) is formed (provided) in a rectangular shape on the upper surface of the film 11 using a resistive material or a conductive material. The printed terminal 40 is connected to the printed wiring 30 and extends from the printed wiring 30 from one side of the longitudinal direction of the film 11 to the other side (a predetermined direction).

[0026] In the longitudinal direction of the film 11, the length L1 of the resistor 20 is longer than the length L2 of the printed terminal 40. In the longitudinal direction of the film 11, the length L3 of the printed wiring 30 is longer than the length L2 of the printed terminal 40 and the length L1 of the resistor 20.

[0027] The wire 50 (second wiring) is formed in a linear shape from a conductive material. The wire 50 is connected to the printed terminal 40 by solder 55.

[0028] The first portion P1 of the film 11, on which the resistor 20 is formed, is bonded (attached) to the portion to be measured 91 by, for example, a thermosetting resin 13 (adhesive). The member to be measured 90, which constitutes the portion to be measured 91, extends from the portion to be measured 91 to a position opposite the second portion P2. That is, the surfaces of the member to be measured 90 facing the first portion P1, the third portion P3, and the second portion P2 are planes located on the same plane. However, the second portion P2 of the film 11, on which the printed terminals 40 are formed, is not bonded to the member to be measured 90 (other members). The thermosetting resin 13 bonds the first portion P1 and a part of the third portion P3 of the film 11 on which the printed wiring 30 is formed to the member to be measured 90, but does not bond the second portion P2 to the member to be measured 90.

[0029] The thermosetting resin 13 only needs to be bonded to the member to be measured 90 in its first portion P1, but it may extend beyond the first portion P1. In that case, the thermosetting resin 13 may be bonded to the member to be measured 90 up to the third portion P3. The film 11 is flexible, and the second portion P2 and the member to be measured 90 are actually in contact. However, the second portion P2 and the member to be measured 90 do not necessarily have to be in contact.

[0030] In the mounting structure of the strain gauge 10 with the above configuration, when the robot operates, strain occurs in the member to be measured 90, for example, as shown by arrow A1. Consequently, strain also occurs in the portion of the film 11 that is bonded to the member to be measured 90 by the thermosetting resin 13, as shown by arrow A2. As a result, the resistor 20 formed in the first portion P1 deforms, and the resistance value of the resistor 20 changes. The robot's controller then measures the resistance value of the resistor 20 and measures the strain of the part to be measured 91 based on the change in resistance value. Based on the measured strain, the controller calculates the torque acting on the joint.

[0031] Here, the second part P2 is not bonded to the member 90 under test. Therefore, even if strain occurs in the member 90 under test as indicated by arrow A1, this strain will not be transmitted to the second part P2. Furthermore, because there is a third part P3 between the first part P1 and the second part P2, the transmission of strain to the second part P2 is effectively suppressed. Consequently, repeated stress acting on the second part P2 is suppressed.

[0032] Figure 3 is a plan view of a comparative example of a strain gauge mounting structure, and Figure 4 is a side view of the same comparative example. Parts identical to those in Figures 1 and 2 are denoted by the same reference numerals.

[0033] The film 911 of the strain gauge 910 does not have the third part P3 described above. The strain gauge 910 does not have the printed circuit board 30 described above. The resistor 20 and the printed terminal 40 are connected.

[0034] The first part P1 and the second part P2 are bonded to the member to be measured 90 by the thermosetting resin 13. In other words, the entire film 911 is bonded to the member to be measured 90 by the thermosetting resin 13.

[0035] When the robot operates, the measured component 90 experiences strain as indicated by arrow A1. Consequently, the entire film 911 also experiences strain as indicated by arrow A2. As a result, stress is repeatedly applied to the second portion P2, making it prone to cracking of the solder 55 or splitting at the boundary between the printed terminal 40 and the solder 55.

[0036] The embodiment described in detail above has the following advantages.

[0037] The first portion P1 of the film 11, on which the resistor 20 is provided, is bonded to the part 91 to be measured. Therefore, the resistor 20 provided in the first portion P1 can be deformed in accordance with the strain of the part 91 to be measured. By measuring the resistance value of the resistor 20 via the wire 50 connected to the printed terminal 40, the strain of the part 91 to be measured can be measured based on the change in the resistance value of the resistor 20. In addition, all components of the strain gauge can be combined into a single film 11, making the handling of the strain gauge 10 easier.

[0038] The second portion P2 of the film 11, on which the printed terminal 40 is provided, is not bonded to any other component (the component to be measured 90). Therefore, even if distortion occurs in the component to be measured 91, distortion of the printed terminal 40 provided on the second portion P2 can be suppressed. Consequently, repeated stress on the printed terminal 40 can be suppressed, and damage to the connection between the printed terminal 40 and the wire 50 can be suppressed. Furthermore, since it is not necessary to bond the second portion P2 to the portion adjacent to the component to be measured 91, the configuration of the portion adjacent to the component to be measured 91 can be set more freely. Therefore, durability can be improved, and a mounting structure for the strain gauge 10 that can be applied to a wider range of configurations can be provided.

[0039] • Printed wiring 30 extends from the resistor 20 in a predetermined direction, and printed terminals 40 extend from the printed wiring 30. Therefore, the printed wiring 30 and printed terminals 40 can be drawn out from the resistor 20 in a predetermined direction. Furthermore, in the predetermined direction, the length L3 of the printed wiring 30 is longer than the length L2 of the printed terminals 40. Consequently, the transmission of strain generated in the measured portion 91 to the second portion P2 via the film 11 can be suppressed by the third portion P3 of the film 11 on which the printed wiring 30 is provided.

[0040] In a given direction, the length L3 of the printed wiring 30 is longer than the length L1 of the resistor 20 (> the length L2 of the printed terminal 40). Therefore, the third part P3 effectively suppresses the transmission of strain generated in the part 91 under test to the second part P2 via the film 11. Furthermore, when the first part P1 is bonded to the part 91 under test with the thermosetting resin 13, even if the thermosetting resin 13 protrudes beyond the first part P1, the third part P3 can suppress the thermosetting resin 13 from reaching the second part P2, and consequently from the second part P2 being bonded to the member 90 under test.

[0041] The member 90 to be measured, which constitutes the portion 91 to be measured, extends from the portion 91 to a position opposite the second portion P2, and the second portion P2 and the member 90 to be measured are in contact. Even with this configuration, the above effects can be achieved because the second portion P2 and the member 90 to be measured are not bonded together.

[0042] The printed terminal 40 and the wire 50 are connected by solder 55. As described above, repeated stress on the printed terminal 40 can be suppressed, thereby preventing cracks in the solder 55 or splitting at the boundary between the printed terminal 40 and the solder 55.

[0043] Furthermore, the above embodiment can also be implemented with the following modifications. Parts identical to those in the above embodiment are denoted by the same reference numerals, and their descriptions are omitted.

[0044] As shown in Figure 5, the printed terminals (not shown) formed on the flexible printed circuit board 15 (printed circuit board) and the printed terminals 40 can also be connected by solder 55 or the like.

[0045] As shown in Figure 6, a predetermined space S may be formed between the member 190 that constitutes the portion 91 to be measured and the second portion P2. With this configuration, the predetermined space S can be effectively utilized. In the strain gauge 110, the resistor 20, printed wiring 30, and printed terminals 40 are provided on the surface 111a of the film 111 opposite to the surface 111b facing the portion 91 to be measured. On the other hand, the printed terminals 140 are provided on the surface 111b of the film 111 facing the portion 91 to be measured. The printed terminals 40 and 140 are connected by a conductive member 70 that penetrates the film 111.

[0046] According to the above configuration, since the predetermined space S is formed between the member to be measured 190 and the second part P2 on which the printed terminal 140 is provided, it is possible to suppress the member to be measured 190 from getting in the way when connecting the wire 50 to the printed terminal 140.

[0047] As shown in Figure 7, a predetermined space S is formed between the member to be measured 190, which constitutes the portion to be measured 91, and the second portion P2. The resistor 20, printed wiring 30, and printed terminals 40 are provided on the surface 211b of the film 211 that faces the portion to be measured 91. The surface 211b of the film 211 is bonded to the member to be measured 190 by a thermosetting resin 13.

[0048] According to the above configuration, since the predetermined space S is formed between the member to be measured 190 and the second part P2 on which the printed terminal 40 is provided, it is possible to suppress the member to be measured 190 from getting in the way when connecting the wire 50 to the printed terminal 40. In addition, in the strain gauge 210, the resistor 20 (first part P1) and the printed wiring 30 (third part P3) may be covered by a cover layer made of polyimide or the like. Similarly, in the above embodiment, the resistor 20 (first part P1) and the printed wiring 30 (third part P3) may be covered by a cover layer made of polyimide or the like.

[0049] The first part P1 can also be attached (sticked) to the part to be measured 91 using adhesive tape or the like.

[0050] • Instead of films 11, 111, and 211, the base material can also be constructed using a plate-shaped substrate.

[0051] The printed wiring 30 is not limited to a straight shape; it may also be bent. In this case as well, it is sufficient that the second portion P2 of the films 11, 111, 211 on which the printed terminals 40 and 140 are provided is not bonded to other components.

[0052] The mounting structure of strain gauges 10, 110, and 210 can be applied not only to robots but also to other industrial machinery and general machinery. Furthermore, the mounting structure of strain gauges 10, 110, and 210 can be applied to speed reducers and motors. Additionally, strain gauges 10, 110, and 210 can be used not only as torque sensors but also as force sensors. [Explanation of Symbols]

[0053] 10... Strain gauge, 11... Film (base material), 13... Thermosetting resin (adhesive), 20... Resistor, 30... Printed wiring (first wiring), 40... Printed terminal (terminal), 50... Wire (second wiring), 55... Solder, 90... Component to be measured, 91... Component to be measured, 110... Strain gauge, 111... Film (base material), 140... Printed terminal (terminal), 190... Component to be measured, 210... Strain gauge, 211... Film (base material), 910... Strain gauge, 911... Film.

Claims

1. A member to be measured with a strain gauge attached, The strain gauge comprises a film-like or plate-like base member, a resistor provided on the base member, a first wiring provided on the base member and connected to the resistor, a terminal provided on the base member and connected to the first wiring, and a second wiring connected to the terminal. The resistor, the first wiring, and the terminal are provided on the base member on the side opposite to the side facing the portion of the member to be measured. The first portion of the base material in which the resistor is provided is adhered to the portion to be measured. The member to be measured extends from the portion to be measured to a position opposite the second portion of the base member on which the terminal is provided. The second part is a member to be measured to which a strain gauge is attached, which is not bonded to any other member and is in contact with the member to be measured.

2. The first wiring extends from the resistor in a predetermined direction, and the terminal extends from the first wiring. The member to be measured to which the strain gauge is attached, according to claim 1, wherein the length of the first wiring is longer than the length of the terminal in the predetermined direction.

3. In the predetermined direction, the length of the resistor is longer than the length of the terminal. The member to be measured to which the strain gauge is attached, according to claim 2, wherein the length of the first wiring is longer than the length of the resistor in the predetermined direction.

4. The terminal and the second wiring are connected by solder, and the member to be measured to which the strain gauge according to any one of claims 1 to 3 is attached.

5. A robot comprising a member to be measured to which a strain gauge according to any one of claims 1 to 4 is attached.

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