JP2021060348A - Fixing device for strain sensor and torque sensor using the same - Google Patents

Abstract

To provide a fixing device for a strain sensor that can prevent reduction of the performance of the sensor and increase of the size of a device structure and that can fix the strain sensor to the structure without fail, and to provide a torque sensor using the fixing device.SOLUTION: A fixing member 41A is in contact with edges of a strain body of a strain sensor, the strain sensor having a first side 41c, a second side 41d parallel to the first side, and a surface 41b with an opening 41f between the first side 41c and the second side 41d, the first side 41c being in contact with the first structure 11 and the second side 41d being on the first structure 11. A cut C1 is provided so that an edge of the strain body is exposed.SELECTED DRAWING: Figure 10

Description

An embodiment of the present invention relates to, for example, a fixing device for a strain sensor provided on a joint of a robot arm and a torque sensor using the same.

The torque sensor has a first structure to which torque is applied, a second structure to which torque is output, and a plurality of strain generating portions as beams connecting the first structure and the second structure. However, a plurality of strain gauges as sensor elements are arranged in these strain generating portions. A bridge circuit is composed of these strain gauges (see, for example, Patent Documents 1, 2 and 3).

Japanese Unexamined Patent Publication No. 2013-096735 Japanese Unexamined Patent Publication No. 2015-049209 Japanese Unexamined Patent Publication No. 2017-172983

Generally, a strain sensor is provided with a plurality of strain gauges as sensor elements on a metal strain generating body. As a method of fixing the strain sensor to the torque sensor, for example, there are a method using welding, a method using an adhesive, and a method using a plurality of screws.

However, when the strain sensor is fixed to the structure by welding, the temperature of the strain-causing body is rapidly increased by welding. Therefore, the composition and shape of the strain-causing body and the strain gauge may change, which may affect the performance of the strain sensor.

Further, when the strain sensor is fixed to the structure using an adhesive, a low-rigidity adhesive is interposed between the strain-causing body and the structure. Therefore, the deformation of the structure is not directly transmitted to the strain-causing body, which may reduce the sensitivity of the strain sensor.

On the other hand, when the strain sensor is fixed to the structure using screws, a pressing member is provided on the strain generating body, and the pressing member is fastened to the structure with screws. It is fixed. In the case of such a configuration, since the pressing member and the strain-causing body are in surface contact with each other, the pressing member needs to maintain a high pressing force with respect to the strain-causing body. In order to maintain a high pressing force, it is necessary to increase the size and rigidity of the pressing member, increase the size of the screw, and increase the number of screws. Therefore, it is difficult to reduce the size and thickness of the torque sensor provided with the holding member and the screw.

The present embodiment provides a strain sensor fixing device capable of reliably fixing the strain sensor to a structure by preventing deterioration of sensor performance and an increase in the size of the device configuration, and a torque sensor using the strain sensor fixing device.

The strain sensor fixing device according to the embodiment is provided between the first side, the second side parallel to the first side, and the first side and the second side, and has an opening. The end of a strain generating body that comprises a surface including a portion, the first side of which is in contact with the first structure, and the second side of which constitutes a strain sensor provided on the first structure. It includes a fixing member that is brought into contact with the portion and is provided with a notch so that the tip of the strain-causing body is exposed, and a screw that is inserted into the opening and screwed into the first structure.

The perspective view which shows the torque sensor to which this embodiment is applied. The plan view which shows except for a part of FIG. The perspective view which takes out the attachment part of the strain sensor shown in FIG. 2 and shows it enlarged. A plan view showing a part of FIG. 2 taken out and enlarged. FIG. 4 is a cross-sectional view taken along the line VV of FIG. FIG. 3 is an enlarged perspective view showing a fixing plate as a fixing member shown in FIG. The cross-sectional view which shows the 1st modification of a fixed plate. The cross-sectional view which shows the 2nd modification of a fixed plate. The cross-sectional view which shows the 3rd modification of a fixed plate. A perspective view of the fixing plate according to the first embodiment as viewed from below. The simplified figure which shows the positional relationship between the fixed plate and the strain sensor which concerns on 1st Embodiment. The simplified figure which shows the positional relationship between the fixed plate and the strain sensor which concerns on 2nd Embodiment. The simplified figure which shows the positional relationship between the fixed plate and the strain sensor which concerns on 3rd Embodiment. The simplified figure which shows the positional relationship between the fixed plate and the strain sensor which concerns on 4th Embodiment.

Hereinafter, embodiments will be described with reference to the drawings. In the drawings, the same parts are designated by the same reference numerals.

(Basic configuration of each embodiment)
First, the basic configuration of each embodiment will be described.
1 and 2 show an example of a torque sensor 10 to which this embodiment is applied. The configuration of the torque sensor 10 is not limited to this, and can be applied to torque sensors having various configurations. Further, the present embodiment can be applied not only to a torque sensor but also to a force sensor using a strain gauge or the like.

In FIG. 1, the torque sensor 10 includes a first structure 11, a second structure 12, a plurality of third structures 13, a plurality of waterproof caps 14, a case 15, a bush 16, and a cable 17.

The first structure 11 and the second structure 12 are formed in an annular shape, and the diameter of the second structure 12 is smaller than the diameter of the first structure 11. The second structure 12 is arranged concentrically with the first structure 11, and the first structure 11 and the second structure 12 are connected by a third structure 13 as a plurality of beams arranged radially. Has been done. The number of the third structure 13 is, for example, eight, and the eight third structures 13 are arranged at equal intervals. The number of the third structure 13 is not limited to eight.

The first structure 11 is connected to, for example, the object to be measured, the second structure 12 is connected to another structure (not shown), and the plurality of third structures 13 are connected to the first structure 11 to the second structure. Torque (moment (Mz) shown in FIG. 2) is transmitted to the structure 12. On the contrary, the second structure 12 is connected to the measured body, the first structure 11 is connected to another structure (not shown), and a plurality of third structures are connected from the second structure 12 to the first structure 11. Torque may be transmitted through the body 13.

In the case of the force sensor, the first structure 11, the second structure 12, and the third structure 13 are deformed three-dimensionally, and the three orthogonal axes (x, y, z) shown in FIG. 2 are related to each other. Forces (Fx, Fy, Fz) and moments (Mx, My, Mz) are detected.

The first structure 11, the second structure 12, and the plurality of third structures 13 are made of metal, for example, stainless steel, but if mechanically sufficient strength can be obtained with respect to the applied torque. , It is also possible to use materials other than metal.

As shown in FIG. 2, a strain sensor 20 described later is arranged corresponding to each third structure 13, and each strain sensor 20 is covered with a cap 14. In FIG. 2, one cap 14 is removed to expose the strain sensor 20. In the present embodiment, the number of strain sensors 20 is the same as the number of the third structure 13, but the number is not limited to this, and the number of strain sensors 20 is the number of the third structure 13. May be less.

The configuration of each strain sensor 20 is the same. The strain sensor 20 is provided between the first structure 11 and the second structure 12. That is, as will be described later, one end of the strain sensor 20 is joined to the first structure 11, and the other end of the strain sensor 20 is joined to the second structure 12.

The second structure 12 has a hollow portion 12a, and the case 15 is attached to the second structure 12 around the hollow portion 12a. Inside the case 15, a processing circuit (not shown) is provided that processes an electric signal supplied from the strain sensor 20 and generates a torque detection signal as a sensor signal.

A bush 16 for holding the cable 17 is provided in a part of the case 15. One end of the cable 17 (not shown) is connected to a processing circuit in the case 15, and the other end of the cable 17 is passed through, for example, a hollow portion 12a. The cable 17 supplies power to the processing circuit from the outside, and outputs a sensor signal processed by the processing circuit to the outside. Since the configuration of the processing circuit is not the essence of the present embodiment, the description thereof will be omitted.

3, FIG. 4, and FIG. 5 show the strain sensor 20 and the mounting structure of the strain sensor 20.
FIG. 3 shows the configuration of the mounting portion of the strain sensor 20. A recess 30 is integrally formed in the first structure 11, the second structure 12, and the plurality of third structures 13. At the bottom of the recess 30, a portion corresponding to the first structure 11 is provided with a first bottom 31a and a second bottom 32a lower than the first bottom 31a. As shown in FIG. 5, the difference in depth between the first bottom portion 31a and the second bottom portion 32a is substantially equal to the thickness of the strain generating body 21.

In the bottom portion of the recess 30, a first bottom portion 31b and a second bottom portion 32b lower than the first bottom portion 31b are also provided in a portion corresponding to the second structure 12. The difference in depth between the first bottom portion 31b and the second bottom portion 32b is also substantially equal to the thickness of the strain generating body 21.

At the bottom of the recess 30, a third bottom 33 lower than the second bottoms 32a and 32b is provided at a portion corresponding to the third structure 13.

An opening 34a is provided in a substantially central portion of the second bottom portion 32a corresponding to the first structure 11, and a screw thread is provided in the opening 34a. An opening 34b is also provided at substantially the center of the second bottom portion 32b corresponding to the second structure 12, and a screw thread is provided inside the opening 34b.

As shown in FIG. 4, the strain sensor 20 is provided between the first structure 11 and the second structure 12 in the recess 30. The strain sensor 20 includes, for example, a metal strain generating body 21 and a plurality of strain gauges 22 as sensor elements arranged on one surface of the strain generating body 21.

The strain gauge 22 is, for example, a thin film resistance element, and its resistance value changes as the strain generating body 21 is deformed. The plurality of strain gauges 22 form a bridge circuit (not shown), and the change in resistance value is detected as an electric signal by the bridge circuit. The plurality of strain gauges 22 are connected to one end of a flexible substrate 23 (shown in FIGS. 2 and 5) provided at the center of the strain generating body 21. The other end of the flexible substrate 23 is connected to the processing circuit in the case 15. The electric signal output from the bridge circuit is supplied to the processing circuit via the flexible substrate 23, and the processing circuit generates a torque detection signal as a sensor signal.

The strain-causing body 21 has, for example, a rectangular shape, and the length of the strain-causing body 21 is longer than the length of the third bottom portion 33. The strain-causing body 21 is fixed to the first structure 11 and the second structure 12 by the fixing device 40a and the fixing device 40b in a state of being arranged in the recess 30.

Specifically, as shown in FIG. 5, the first end portion of the strain generating body 21 is placed on the second bottom portion 32a of the first structure 11, and the second end portion of the strain generating body 21 is It is placed on the second bottom 32b of the second structure 12. That is, the strain-causing body 21 is arranged between the opening 34a of the second bottom 32a of the first structure 11 and the opening 34b of the second bottom 32b of the second structure 12.

The first end portion of the strain generating body 21 is fixed to the first structure 11 by a fixing device 40a arranged in a portion corresponding to the first structure 11 of the recess 30, and the second end portion of the strain generating body 21 is fixed to the first structure 11. , It is fixed to the second structure 12 by the fixing device 40b arranged in the portion corresponding to the second structure 12 of the recess 30.

The fixing device 40a and the fixing device 40b have the same configuration, and the fixing device 40a and the fixing device 40b each include a fixing plate 41 as a fixing member and a screw 42. In the fixing device 40a, the fixing plate 41 is attached to the first structure 11 by a screw 42 screwed into the opening 34a. In the fixing device 40b, the fixing plate 41 is attached to the second structure 12 by a screw 42 screwed into the opening 34b.

The screw 42 is inserted from above the fixing plate 41 and screwed into the opening 34a of the first structure 11 or the opening 34b of the second structure 12.

When the screw 42 of the fixing device 40a is tightened, the first end portion of the strain generating body 21 is fixed to the first structure 11 by the fixing plate 41, and when the screw 42 of the fixing device 40b is tightened, the strain generating body 21 The second end is fixed to the second structure 12 by the fixing plate 41.

(Structure of fixed plate)
FIG. 6 shows one form of the fixed plate 41 according to the present embodiment.
The fixing plate 41 is made of, for example, the same metal as the first structure 11, but is not limited to this, and may be made of another material.

The fixed plate 41 has, for example, a rectangular parallelepiped main body 41a. The fixed plate 41 and the main body 41a are the same, and the fixed plate 41 is also simply referred to as the main body 41a. A first protrusion 41c is provided along the first side of, for example, the bottom surface 41b of the main body 41a, and a second protrusion 41d is provided along the second side parallel to the first side. The first protrusion 41c and the second protrusion 41d are linear and project from the bottom surface 41b in the same direction. Therefore, the bottom surface 41b is arranged at a position away from the line connecting the first protrusion 41c and the second protrusion 41d. Further, the main body 41a has an opening 41f penetrating from the surface 41e to the bottom surface 41b.

The width W1 of the fixed plate 41 is narrower than the width W2 of the recess 30 (shown in FIG. 4), and the length L1 of the fixed plate 41 is the length L2 of the portion of the recess 30 corresponding to the first structure 11 (FIG. 4). The length of the portion of the recess 30 corresponding to the second structure 12 is shorter than L3. Here, the relationship between L2 and L3 is, for example, L2 <L3, but the relationship is not limited to this. That is, the length of the fixing plate 41 allows the fixing plate 41 to come into contact with the first bottom portion 31a and the first end portion of the strain generating body 21 when the screw 42 is tightened, or the first bottom portion 31b and the strain generating body 21. It may be long enough to contact the second end of the.

Specifically, as shown in FIGS. 4 and 5, in a state where the two fixing plates 41 are inserted into the portion of the recess 30 corresponding to the first structure 11 and the portion corresponding to the second structure 12. It is sufficient that the first protrusion 41c of each fixing plate 41 can make line contact with the first bottom portion 31a or the first bottom portion 31b, and the second protrusion 41d can make line contact with the first end portion or the second end portion of the strain generating body 21.

In this way, in a state where the two fixing plates 41 are inserted into the recesses 30, the screws 42 are inserted into the openings 41f of each fixing plate 41, and the openings 34a of the first structure 11 or the second structure By being screwed into the opening 34b of the body 12, the first protrusion 41c of the fixing plate 41 is in line contact with the first bottom 31a or the first bottom 31b, and the second protrusion 41d is the first end of the strain generating body 21. Line contact with the portion or the second end.

As shown in FIG. 6, the first protrusion 41c of the fixing plate 41 is linear, and the first protrusion 41c is in line contact with the first bottom portion 31b. However, the present invention is not limited to this, and for example, as shown by the broken line in FIG. 6, the first protrusion 41c may be a point-like protrusion, and the first protrusion 41c may make point contact with the first bottom portion 31b. The point-shaped first protrusion 41c is provided at substantially the center of the first side, but for example, two first protrusions may be provided at both ends of the first side. Alternatively, three first protrusions may be provided at the center of the first side and at both ends.

(Effect of the basic configuration of the embodiment)
According to the above embodiment, the fixing plate 41 has a first protrusion 41c and a second protrusion 41d, and by tightening the screw 42, the first protrusion 41c comes into line contact with the first bottom portion 31a or the first bottom portion 31b. , The second protrusion 41d makes line contact with the first end or the second end of the strain generating body 21. Therefore, for example, the strain generating body 21 can be fixed to the first structure 11 and the second structure 12 with a higher pressure than in the case where the strain generating body and the fixing plate are in surface contact with each other. Therefore, it is possible to reduce the variation in the fixing strength of the strain generating body 21 with respect to the first structure 11 and the second structure 12, and it is possible to prevent the sensor performance from being lowered.

Moreover, according to the fixing method using the fixing plate 41 of the present embodiment, the strain generating body 21 is brought into the first structure 11 and the first structure 11 by simply bringing the second protrusion 41d of the fixing plate 41 into line contact with the strain generating body 21. 2 It can be fixed to the structure 12. Therefore, thermal deformation of the strain generating body 21 and the strain gauge can be prevented, for example, when the strain generating body 21 is fixed to the first structure 11 and the second structure 12 by welding. Further, unlike the case where the strain generating body 21 is fixed with an adhesive, the low rigidity portion does not intervene between the strain generating body 21 and the first structure 11 and the second structure 12. Therefore, according to the fixing method using the fixing plate 41 of the present embodiment, the force applied to the first structure and the second structure 12 can be reliably transmitted to the strain generating body 21, and the performance of the sensor. Can be improved.

Moreover, the fixing devices 40a and 40b are composed of one fixing plate 41 and one screw 42. Therefore, the number of parts is small, and it is possible to prevent the fixing devices 40a and 40b from becoming large and the torque sensor 10 from becoming large.

Further, since the fixing devices 40a and 40b are composed of one fixing plate 41 and one screw 42, the fixing devices 40a and 40b can be easily assembled.

Further, the screw 42 is inserted from the upper side of the fixing plate 41 and screwed into the opening 34a of the first structure 11 or the opening 34b of the second structure 12. Therefore, for example, the assembly work is facilitated as compared with the case where the screw 42 is inserted from the opening 34a of the first structure 11 or the opening 34b side of the second structure 12 and screwed into the fixing plate 41. Is possible.

(Modification example of fixed plate)
(First modification)
FIG. 7 shows a first modification of the fixed plate. In the case of the embodiment shown in FIG. 6, the main body 41a is provided with a first protrusion 41c and a second protrusion 41d on a flat bottom surface 41b.

On the other hand, in the first modification, for example, the rectangular parallelepiped main body 51a of the fixed plate 51 has a curved bottom surface 51b, and the first side of the bottom surface 51b functions as the first protrusion 51c, and the first The second side parallel to the side functions as the second protrusion 51d. Therefore, the curved bottom surface 51b is arranged at a position away from the line connecting the first protrusion 51c and the second protrusion 51d. An opening 51f penetrating the surface 51e is provided at the center of the bottom surface 51b.

The same effect as that of the above-described embodiment can be obtained by the above-mentioned first modification. Moreover, according to the second modification, since the bottom surface 51b of the main body 51a is curved, the elasticity of the fixing plate 51 is improved. Therefore, the strain generating body 21 can be reliably fixed by the fixing plate 51.

Further, according to the first modification, the first protrusion 51c and the second protrusion 51d can be formed only by processing the bottom surface of the main body 51a into a curved shape, so that the production can be facilitated.

(Second modification)
FIG. 8 shows a second modification of the fixed plate. In the first modification shown in FIG. 7, the main body 51a has a curved bottom surface 51b.

On the other hand, in the second modification, the fixed plate 61, for example, the rectangular parallelepiped main body 61a, is entirely curved. Therefore, it has a curved bottom surface 61b, the first side of the bottom surface 61b functions as the first protrusion 61c, and the second side parallel to the first side functions as the second protrusion 61d. Therefore, the curved bottom surface 61b is arranged at a position away from the line connecting the first protrusion 61c and the second protrusion 61d. An opening 61f penetrating the surface 61e is provided at the center of the bottom surface 61b.

The same effect as that of the above-described embodiment can also be obtained by the above-mentioned second modification. Moreover, according to the second modification, since the entire main body 61a is curved, the elasticity of the fixing plate 61 is improved. Therefore, the strain generating body 21 can be more reliably fixed by the fixing plate 61.

Further, according to the second modification, the first protrusion 61c and the second protrusion 61d can be formed only by processing the main body 61a into a curved shape, so that the production can be facilitated.

(Third modification example)
FIG. 9 shows a third modification of the fixed plate. In the above embodiment and each modification, the main body of the fixing plate is provided with protrusions on two sides.

On the other hand, in the third modification shown in FIG. 9, the main body 71a of the fixed plate 71 is, for example, a rectangular parallelepiped, and protrusions 71c are provided along the four sides of the bottom surface 71b of the main body 71a. That is, the protrusion 71c is provided around the bottom surface 71b.

The same effect as that of the above-described embodiment can be obtained by the above-mentioned third modification. Moreover, by providing the protrusion 71c around the bottom surface 71b, the rigidity of the fixing plate 71 can be increased, and the strain generating body 21 can be fixed more reliably.

Further, the case where the shape of the main body 71a of the fixed plate 71 is a rectangular parallelepiped and the shape of the bottom surface 71b is rectangular has been described, but the shape of the main body 71a of the fixed plate 71 is a cube and the shape of the bottom surface 71b is a square. It is also possible. In this case, the strain generating body 21 can be fixed by using any of the four parallel sides, whichever is parallel. Therefore, it is not necessary to consider the orientation of the fixing plate 71 with respect to the recess 30a, so that the assembly work can be simplified.

Also in the first modification and the second modification, it is possible to provide protrusions around the main body.

(First Embodiment)
In the first embodiment, the changed points will be mainly described with reference to the above-mentioned basic configuration, but the same changes may be made with reference to the first modification to the third modification. The same applies to the subsequent embodiments.

FIG. 10 is a perspective view of the fixing plate 41A according to the first embodiment of the present invention as viewed from below. FIG. 11 is a simplified diagram showing the positional relationship between the fixed plate 41A and the strain sensor 20 according to the present embodiment.

In the present embodiment, the structure in which the fixing plate 41A is brought into line contact or point contact with the first structure 11 or the second structure 12 and the strain generating body 21 will be mainly described, but surface contact may be used, or the like. It may be contacted in any way. The same applies to the subsequent embodiments.

The fixed plate 41A is a fixed plate 41 shown in FIG. 6 having a notch C1 on the strain sensor 20 side so as to be connected to the opening 41f.

The notch C1 exposes the tip of the strain sensor 20 without being covered by the fixing plate 41A. Therefore, even if the fixed plate 41A is arranged on the strain sensor 20, the operator who attaches the strain sensor 20 can see the tip of the strain sensor 20 from the notch C1 of the fixed plate 41A.

The operator visually confirms the position of the strain sensor 20 by visually observing the tip of the strain sensor 20 from the notch C1 in a state where the fixed plate 41A is arranged on the strain sensor 20. After confirming the position of the strain sensor 20, the operator fixes the fixing plate 41A with the screw 42.

According to the present embodiment, by making a notch C1 in the fixed plate 41A, the position of the strain sensor 20 in particular the longitudinal direction (the direction connecting the first end portion and the second end portion of the strain generating body 21) is accurately aligned. The strain sensor 20 can be fixed in this state.

(Second Embodiment)
FIG. 12 is a simplified diagram showing the positional relationship between the fixed plate 41B and the strain sensor 20 according to the second embodiment of the present invention.

The fixed plate 41B is the fixed plate 41A shown in FIG. 11 in which the notch C1 is replaced with the notch C2. The notch C2 is provided on the strain sensor 20 side of the fixed plate 41A so as not to be connected to the opening 41f. The notch C2 is formed in a rectangular shape wider than the notch C1. For example, the width of the notch C2 is substantially the same as the diameter of the opening 41f.

The notch C2 exposes the tip of the strain sensor 20 without being covered by the fixing plate 41B. Therefore, even if the fixed plate 41B is arranged on the strain sensor 20, the operator can see the tip of the strain sensor 20 from the notch C2 of the fixed plate 41B. The method of attaching the fixing plate 41B by the operator is the same as that of the first embodiment.

According to the present embodiment, in addition to the action and effect of the first embodiment, the width of the notch C2 is set to the first width without significantly weakening the rigidity of the fixing plate 41B by making the notch C2 so as not to connect with the opening 41f. The width of the notch C1 according to the embodiment can be made wider so that the tip of the strain sensor 20 can be easily seen.

(Third Embodiment)
FIG. 13 is a simplified diagram showing the positional relationship between the fixed plate 41C and the strain sensor 20 according to the third embodiment of the present invention.

The fixed plate 41C is the fixed plate 41A shown in FIG. 11 in which the notch C1 is replaced with two notches C3. Each notch C3 is formed on the strain sensor 20 side of the fixed plate 41C in a direction perpendicular to the longitudinal direction of the strain sensor 20 so that the width of the portion of the fixed plate 41C that holds the strain sensor 20 is narrower than the width of the strain sensor 20. It is provided at both ends where it is located. The notch C3 may be provided in only one of the two (one side of the tip).

The two notches C3 expose the tip of the strain sensor 20 and the left and right ends of the tip without being covered by the fixing plate 41C. Therefore, even if the fixed plate 41C is arranged on the strain sensor 20, the operator can see the tip of the strain sensor 20 and the left and right ends of the tip from the notch C3 of the fixed plate 41C. The method of attaching the fixing plate 41C by the operator is the same as that of the first embodiment.

According to the present embodiment, in addition to the action and effect of the first embodiment, the left and right ends of the tip of the strain sensor 20 can be confirmed from the two notches C3, so that the operator can adjust the strain sensor 20 to an appropriate position. It becomes easier to do.

(Fourth Embodiment)
FIG. 14 is a simplified diagram showing the positional relationship between the fixed plate 41D and the strain sensor 20 according to the fourth embodiment of the present invention.

The fixed plate 41D is the fixed plate 41A shown in FIG. 11 in which the notch C1 is replaced with the notch C4. The notch C4 is provided so that an elongated hole extending in the width direction of the strain sensor 20 is formed on the strain sensor 20 side of the opening 41f. For example, the width of the notch C4 is substantially the same as the diameter of the opening 41f.

The notch C4 exposes the tip of the strain sensor 20 without being covered by the fixed plate 41D. Therefore, even if the fixed plate 41D is arranged on the strain sensor 20, the operator can see the tip of the strain sensor 20 from the notch C4 of the fixed plate 41D. The method of attaching the fixing plate 41D by the operator is the same as that of the first embodiment.

According to the present embodiment, in addition to the action and effect according to the first embodiment, the size of the notch C4 can be suppressed to the minimum by forming the hole shape. As a result, various effects due to the notch C4 (for example, the effect on the rigidity of the fixed plate 41D or the sensitivity of the sensor) can be minimized.

In each embodiment, the cuts C1 to C4 may not be provided in both of the two fixing devices 40a and 40b as long as they are provided in at least one of the two fixing devices 40a and 40b. Further, the notch is not limited to C1 to C4 according to each embodiment, and any notch may be provided as long as the tip of the strain sensor 20 can be seen.

In addition, the present invention is not limited to each of the above embodiments as it is, and at the implementation stage, the components can be modified and embodied within a range that does not deviate from the gist thereof. In addition, various inventions can be formed by appropriately combining the plurality of components disclosed in each of the above embodiments. For example, some components may be removed from all the components shown in the embodiments. In addition, components across different embodiments may be combined as appropriate.

10 ... Torque sensor, 11 ... 1st structure, 12 ... 2nd structure, 13 ... 3rd structure, 20 ... Strain sensor, 21 ... Distortion body, 40a, 40b ... Fixing device, 41 ... Fixed plate, 41a , 51a, 61a, 71a ... Main body, 41b, 51b, 61b, 71b ... Bottom surface, 41c, 51c, 61c ... First protrusion, 41d, 51d, 61d ... Second protrusion, 41f, 51f, 61f ... Opening, 42 ... Screws, C1, C2, C3, C4 ... Notches.

Claims (6)

The first side, the second side parallel to the first side, and a surface provided between the first side and the second side and including an opening are provided, and the first side is provided. One side is in contact with the first structure, the second side is in contact with the end of the strain generating body constituting the strain sensor provided on the first structure, and the tip of the strain generating body is contacted. A fixing member with a notch so that
A screw inserted into the opening and screwed into the first structure,
A strain sensor fixing device comprising. The strain sensor fixing device according to claim 1, wherein the fixing member is provided with the notch so as to be connected to the opening. The strain sensor fixing device according to claim 1, wherein the fixing member is provided with the notch so as not to be connected to the opening. The strain sensor fixing device according to claim 3, wherein the fixing member is provided with the notch so as to form a hole on the strain sensor side of the opening. The strain sensor fixing device according to claim 1, wherein the fixing member is provided with the notch so that at least one side of the tip of the strain-causing body is exposed. The first structure and
The second structure and
A plurality of third structures connecting the first structure and the second structure,
A strain generating body constituting a strain sensor provided between the first structure and the second structure, and
A first fixing device provided in the first structure and fixing the first end portion of the strain-causing body to the first structure.
A second fixing device provided in the second structure and fixing the second end portion of the strain-causing body to the second structure.
Equipped with
Each of the first fixing device and the second fixing device
The first side, the second side parallel to the first side, and a surface provided between the first side and the second side and including an opening are provided, and the first side is provided. A fixing member whose side 1 is in contact with the first structure and whose second side is in contact with the end of the strain generating body constituting the strain sensor provided on the first structure.
It comprises a screw that is inserted into the opening and screwed into the first structure.
A torque sensor, wherein the first fixing device and at least one fixing member of the second fixing device are provided with a notch so that the tip of the strain generating body is exposed.

Images