Member to be measured with mounted strain gauge, and 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 a structure for attaching a strain gauge to a part to be measured. [Background technology]

[0002] In a conventional strain gauge mounting structure of this type, the mutually continuous end faces of a circular diaphragm and a circular boss formed integrally with the outer periphery of the diaphragm are flat surfaces located on the same plane, the resistance wire of the strain gauge is attached to the flat surface on the diaphragm side, and terminals for connecting the resistance wire to lead wires are attached to the flat surface on the boss side (see Patent Document 1).In Patent Document 1, unlike when a strain gauge is attached to a curved surface, the strain gauge can be reliably attached to the flat surface, thereby avoiding a decrease in reliability due to peeling, etc., and further, because the terminals are attached to the flat surface on the boss side, which is not subject to elastic deformation, this part will not be exposed to repeated elastic deformation and thereby not break. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-69402 Summary of the Invention [Problem to be solved by the invention]

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

[0005] The present invention has been made to solve the above-mentioned problems, and its main object is to provide a strain gauge mounting structure that can improve durability and is applicable to a wider range of configurations. [Means for solving the problem]

[0006] The first means for solving the above problem is: A structure in which a strain gauge is attached to a 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; a first portion of the base member on which the resistor is provided is adhered to the portion to be measured; The second portion of the base member where the terminal is provided is not bonded to another member.

[0007] According to the above configuration, the strain gauge includes 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 where the resistor is provided is adhered to the measured portion. This allows the resistor provided on the first portion to deform in response to strain in the measured portion. Then, by measuring the resistance value of the resistor via the second wiring connected to the terminal, strain in the measured portion can be measured based on changes in the resistance value of the resistor. Furthermore, each component of the strain gauge can be integrated into a single base member, making the strain gauge easier to handle.

[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 strain occurs in the measured portion, the terminal provided in the second portion can be prevented from being distorted. Therefore, repeated application of stress to the terminal can be prevented, and damage to the connection between the terminal and the second wiring can be prevented. Furthermore, since there is no need to bond the second portion to the portion adjacent to the measured portion, the configuration of the portion adjacent to the measured portion can be more freely set. Therefore, a strain gauge mounting structure can be provided that can improve durability and be applicable to a wider range of configurations.

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

[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 the predetermined direction. Furthermore, the length of the first wiring is longer than the length of the terminal in the predetermined direction. Therefore, the portion of the base member where the first wiring is provided (hereinafter referred to as the "third portion") can prevent strain generated in the portion under measurement from being transmitted to the second portion via the base member.

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

[0012] According to the above configuration, the length of the first wiring in the predetermined direction is longer than the length of the resistor (>length of the terminal). Therefore, the third portion can effectively prevent strain generated in the portion to be measured from being transmitted to the second portion via the underlying member. Furthermore, when the first portion is bonded to the portion to be measured with an adhesive, even if the adhesive protrudes outside the first portion, the third portion can prevent the adhesive from reaching the second portion and, ultimately, from bonding the second portion to another member.

[0013] In a fourth aspect, the member to be measured that constitutes the portion to be measured extends from the portion to a position facing the second portion, and the second portion and the member to be measured are in contact with each other. Even with this configuration, the second portion and the member to be measured (another member) are not bonded together, so that the same effects as those of the first aspect can be achieved.

[0014] In addition, in the fifth aspect, a predetermined space is formed between the second part and the member to be measured that constitutes the portion to be measured. With this configuration, the predetermined space can be effectively utilized.

[0015] If a terminal is provided on the surface of the base member facing the part to be measured, the part to be measured may become an obstacle when connecting the second wiring to the terminal.

[0016] In this regard, in a sixth aspect, based on the fifth aspect, the terminal is provided on the surface of the base member facing the part to be measured. With this configuration, the predetermined space is formed between the part to be measured and the second part on which the terminal is provided, so that the part to be measured can be prevented from interfering with connecting the second wiring to the terminal.

[0017] Specifically, based on any one of the first to sixth means, a seventh means can be adopted in which the terminal and the second wiring are connected by solder. This configuration is based on the premise that repeated application of stress to the terminal can be suppressed, and therefore cracks in the solder and splitting at the boundary between the terminal and the solder can be suppressed.

[0018] Specifically, as in an eighth aspect, a configuration such as a robot equipped with the strain gauge mounting structure according to any one of the first to seventh aspects can be adopted. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 2 is a plan view of the strain gauge mounting structure. [Figure 2] FIG. 2 is a side view of the strain gauge mounting structure. [Figure 3] FIG. 10 is a plan view of a comparative example of a strain gauge mounting structure. [Figure 4] FIG. 10 is a side view of a comparative example of a strain gauge mounting structure. [Figure 5] FIG. 10 is a side view of a modified example of the strain gauge mounting structure. [Figure 6] FIG. 10 is a side view of another modified example of the strain gauge mounting structure. [Figure 7] FIG. 10 is a side view of another modified example of the strain gauge mounting structure. DETAILED DESCRIPTION OF THE INVENTION

[0020] An embodiment of a strain gauge mounting structure provided in a robot joint will be described below with reference to the drawings. The robot's controller (controller) measures the resistance value of the strain gauge resistor and measures the strain of the measured part based on the change in the resistance value. The controller calculates the torque acting on the joint based on the measured strain. In other words, the strain gauge is used as a torque sensor that detects torque. Note that since the method of calculating torque in this way is well known, a detailed description will be omitted.

[0021] 1 and 2, a strain gauge 10 measures the strain of a measurement target portion 91 of a measurement target member 90. The strain gauge 10 includes a film 11, a resistor 20, a printed wiring 30, a printed terminal 40, a wire 50, and a solder 55. Note that the resistor 20, the printed wiring 30, and the printed terminal 40 are not shown in FIG.

[0022] The film 11 (underlying member) is made of, for example, polyimide (insulating resin) and is formed in the shape of a rectangular film.

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

[0024] The printed wiring 30 (first wiring) 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 wiring 30 is connected to the resistor 20 and extends from the resistor 20 from one side of the longitudinal direction of the film 11 to the other side (predetermined direction).

[0025] The printed terminal 40 (terminal) is formed (provided) in a rectangular shape from a resistive material or a conductive material on the upper surface of the film 11. 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 (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 made of a conductive material and is connected to the printed terminal 40 by solder 55.

[0028] The first portion P1 of the film 11, where the resistor 20 is formed, is adhered (attached) to the measurement portion 91 by, for example, a thermosetting resin 13 (adhesive). The measurement member 90 constituting the measurement portion 91 extends from the measurement portion 91 to a position facing the second portion P2. That is, the surfaces of the measurement member 90 facing the first portion P1, the third portion P3, and the second portion P2 are flat and located on the same plane. However, the second portion P2 of the film 11, where the printed terminal 40 is formed, is not adhered to the measurement member 90 (another member). The thermosetting resin 13 adheres the first portion P1 and a part of the third portion P3 of the film 11, where the printed wiring 30 is formed, to the measurement member 90, but does not adhere the second portion P2 to the measurement member 90.

[0029] It is sufficient that only the first portion P1 of the thermosetting resin 13 is adhered to the member to be measured 90, but it may protrude beyond the first portion P1. In that case, the thermosetting resin 13 may be adhered 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 with each other. However, the second portion P2 and the member to be measured 90 do not necessarily have to be in contact with each other.

[0030] In the strain gauge 10 mounting structure configured as described above, when the robot moves, strain occurs in the measured member 90, for example, as indicated by arrow A1. Accordingly, strain also occurs in the portion of the film 11 that is bonded to the measured member 90 by the thermosetting resin 13, as indicated by arrow A2. This causes deformation of the resistor 20 formed in the first portion P1, changing the resistance value of the resistor 20. The robot's controller then measures the resistance value of the resistor 20 and measures the strain in the measured portion 91 based on the change in resistance value. The controller calculates the torque acting on the joint based on the measured strain.

[0031] Here, the second portion P2 is not bonded to the member to be measured 90. Therefore, even if distortion occurs in the member to be measured 90 as shown by the arrow A1, this distortion will not be transmitted to the second portion P2. Furthermore, the presence of the third portion P3 between the first portion P1 and the second portion P2 effectively prevents the distortion from being transmitted to the second portion P2. Therefore, repeated application of stress to the second portion P2 is prevented.

[0032] Fig. 3 is a plan view of a comparative example of a strain gauge mounting structure, and Fig. 4 is a side view of the comparative example of a strain gauge mounting structure. Note that the same parts as in Figs. 1 and 2 are given the same reference numerals.

[0033] The film 911 of the strain gauge 910 does not include the third portion P3. The strain gauge 910 does not include the printed wiring 30. The resistor 20 and the printed terminal 40 are connected.

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

[0035] When the robot operates, distortion occurs in the member to be measured 90 as shown by arrow A1. Accordingly, distortion also occurs in the entire film 911 as shown by arrow A2. As a result, stress is repeatedly applied to the second portion P2, which makes it easier for cracks to occur in the solder 55 or for the boundary between the printed terminal 40 and the solder 55 to break.

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

[0037] The first portion P1 of the film 11, on which the resistor 20 is provided, is adhered to the measured portion 91. Therefore, the resistor 20 provided in the first portion P1 can be deformed in accordance with the strain of the measured portion 91. Then, by measuring the resistance value of the resistor 20 via the wire 50 connected to the printed terminal 40, the strain of the measured portion 91 can be measured based on the change in the resistance value of the resistor 20. Furthermore, each component of the strain gauge can be integrated into a single film 11, making the strain gauge 10 easier to handle.

[0038] The second portion P2 of the film 11, on which the printed terminal 40 is provided, is not bonded to another member (the member to be measured 90). Therefore, even if distortion occurs in the member to be measured 91, distortion of the printed terminal 40 provided in the second portion P2 can be suppressed. This suppresses repeated application of stress to the printed terminal 40 and suppresses damage to the connection between the printed terminal 40 and the wire 50. Furthermore, since there is no need to bond the second portion P2 to the portion adjacent to the member to be measured 91, the configuration of the portion adjacent to the member to be measured 91 can be more freely set. This makes it possible to provide an attachment structure for a strain gauge 10 that can improve durability and be applicable to a wider range of configurations.

[0039] The printed wiring 30 extends from the resistor 20 in a predetermined direction, and the printed terminal 40 extends from the printed wiring 30. This allows the printed wiring 30 and the printed terminal 40 to be drawn out from the resistor 20 in the predetermined direction. In addition, the length L3 of the printed wiring 30 is longer than the length L2 of the printed terminal 40 in the predetermined direction. Therefore, the third portion P3 of the film 11, where the printed wiring 30 is provided, can prevent strain generated in the measurement portion 91 from being transmitted to the second portion P2 via the film 11.

[0040] In a predetermined 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 portion P3 can effectively prevent strain generated in the measured portion 91 from being transmitted to the second portion P2 via the film 11. Furthermore, when the first portion P1 is bonded to the measured portion 91 with the thermosetting resin 13, even if the thermosetting resin 13 protrudes outside the first portion P1, the third portion P3 can prevent the thermosetting resin 13 from reaching the second portion P2 and thereby prevent the second portion P2 from being bonded to the measured member 90.

[0041] The measured member 90 constituting the measured portion 91 extends from the measured portion 91 to a position facing the second portion P2, and the second portion P2 abuts the measured member 90. Even with this configuration, the second portion P2 and the measured member 90 are not bonded together, so the above-mentioned effects can be achieved.

[0042] The printed terminal 40 and the wire 50 are connected by the solder 55. As described above, repeated application of stress to the printed terminal 40 can be suppressed, and therefore cracks in the solder 55 and breakage at the boundary between the printed terminal 40 and the solder 55 can be suppressed.

[0043] The above embodiment can be modified as follows: The same parts as those in the above embodiment are denoted by the same reference numerals and the description thereof will be omitted.

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

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

[0046] According to the above configuration, the predetermined space S is formed between the measured member 190 and the second part P2 on which the printed terminal 140 is provided, thereby preventing the measured member 190 from interfering with connecting the wire 50 to the printed terminal 140.

[0047] 7, a predetermined space S is formed between the second portion P2 and the member to be measured 190 constituting the portion to be measured 91. The resistor 20, the printed wiring 30, and the printed terminal 40 are provided on a surface 211b of the film 211 facing the portion to be measured 91. The surface 211b of the film 211 is bonded to the member to be measured 190 with a thermosetting resin 13.

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

[0049] The first portion P1 can also be adhered (attached) to the measurement portion 91 using adhesive tape or the like.

[0050] Instead of the films 11, 111, and 211, the base member may be made of a plate-shaped substrate.

[0051] The printed wiring 30 is not limited to a linear shape, but may be a curved shape. In this case, it is also acceptable as long as the second portion P2 of the film 11, 111, 211 on which the printed terminals 40, 140 are provided is not adhered to another member.

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

[0053] 10...strain gauge, 11...film (underlying material), 13...thermosetting resin (adhesive), 20...resistor, 30...printed wiring (first wiring), 40...printed terminal (terminal), 50...wire (second wiring), 55...solder, 90...measuring element, 91...measured part, 110...strain gauge, 111...film (underlying material), 140...printed terminal (terminal), 190...measuring element, 210...strain gauge, 211...film (underlying material), 910...strain gauge, 911...film.

Claims

1. A structure in which a strain gauge is attached to a 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; a first portion of the base member on which the resistor is provided is adhered to the portion to be measured; A strain gauge mounting structure, wherein a second portion of the base member on which the terminal is provided is not bonded to another member.

2. the first wiring extends from the resistor in a predetermined direction, and the terminal extends from the first wiring, 2. The strain gauge mounting structure according to claim 1, wherein the length of the first wire is longer than the length of the terminal in the predetermined direction.

3. The length of the resistor is longer than the length of the terminal in the predetermined direction; 3. The strain gauge mounting structure according to claim 2, wherein the length of the first wiring is longer than the length of the resistor in the predetermined direction.

4. a measurement member constituting the measurement portion extends from the measurement portion to a position facing the second portion, 4. The strain gauge mounting structure according to claim 1, wherein the second portion and the member to be measured are in contact with each other.

5. 4. The strain gauge mounting structure according to claim 1, wherein a predetermined space is formed between the second portion and a member to be measured that constitutes the measured portion.

6. 6. The strain gauge mounting structure according to claim 5, wherein the terminal is provided on a surface of the base member facing the portion to be measured.

7. 7. The strain gauge mounting structure according to claim 1, wherein the terminal and the second wiring are connected by soldering.

8. A robot comprising the strain gauge mounting structure according to any one of claims 1 to 7.

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