JPH0566534U - Triaxial semiconductor force sensor - Google Patents

Abstract

(57) [Abstract] [Objective] In a triaxial semiconductor force sensor, the influence of deformation of the strain-generating body caused by mounting the strain-generating body on the mounting surface is less likely to be transmitted to the semiconductor strain gauge. [Structure] By providing a thin-walled portion on the strain-flexing body, the deformation of the strain-generating body that occurs when the strain-flexing body is screwed is deformed by the large deformation of the thin-walled portion. Reduce the amount,
Furthermore, preferably three legs for attachment are provided on the flexure element,
The flatness of the mounting surface is less likely to affect the flexure element.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an input device of a force sensor used for automatic setting of grasping force in an automated manufacturing equipment or an article grasping part of a robot, and in particular, a silicon single crystal substrate having a diffusion type strain gauge formed into a strain body. The present invention relates to a three-dimensional force sensor formed by joining.

[0002]

[Prior Art]

 As shown in FIGS. 8 and 9, the detection portion of the triaxial semiconductor force sensor, which is the subject of the present invention, is composed of a disc-shaped strain element and a semiconductor strain gauge using a silicon single crystal substrate. .. When an external force is applied to the input shaft 5 of the flexure element, the flexure element 1 is deformed. Deformation increases as the rigidity decreases, so the central portion A of the strain-generating body 1 is made thin as shown in FIG. 9 to reduce the rigidity, and the semiconductor strain gauge 2 is bonded on top of it so that there is no gap. When the center portion A is deformed, the semiconductor strain gauge 2 is distorted according to the deformation. The semiconductor strain gauge detects a change in strain by utilizing the phenomenon that the resistivity changes when the amount of strain changes, that is, the piezoresistance effect. The magnitude and direction of the external force applied to the input shaft 5 are known by detecting the change in strain of the central portion A.

When actually used as a detection part of a triaxial semiconductor force sensor, after the semiconductor strain gauge 2 is bonded to the strain body 1, the strain body 1 is protected to protect the semiconductor strain gauge 2. The cover 11 is attached so as to cover the central portion A. Since the cover 11 projects from the outer peripheral surface of the flexure element 1 as shown in FIG. 9, when the flexure element 1 is attached, the mounting surface 9 is provided with a hole 9a into which the cover 11 can be inserted. The hole 9a is preferably made larger than the cover 11 so that the cover 11 and the hole 9a do not come into contact with each other.

After inserting the cover 11 into the hole 9 a, the flexure element 1 is fixed to the mounting surface 9 with a plurality of screws 6. At this time, if the tightening force of each screw is not uniform or the mounting surface 9 is not flat, the flexure element 1 will be deformed. When the flexure element 1 is deformed, the semiconductor strain gauge 2 is distorted and acts as if an external force is applied to the input shaft 5.

Therefore, after fixing the strain element 1 to the mounting surface 9, the amount of strain generated in the semiconductor strain gauge 2 is detected, and the display device of the triaxial semiconductor force sensor is adjusted to detect the strain. In the case of quantity, zero the magnitude of the force so that it is displayed as zero. After making this adjustment, the triaxial semiconductor force sensor will be used.

[0006]

[Problems to be solved by the device]

 However, it is very time-consuming to adjust the display device each time it is attached. Therefore, it is very inconvenient when it is used in a method of changing the mounting position many times. In addition, if the deformation that occurs when the flexure element is attached is large, the measurable range of the semiconductor strain gauge will be extremely narrow with respect to the force applied to the input shaft in a specific direction, which is inconvenient for use. It happened.

Therefore, a method of increasing the rigidity of the mounting portion of the flexure element to eliminate the deformation of the flexure element caused by the attachment can be considered. However, in order to increase the rigidity of the mounting portion of the strain-flexing body, the thickness of the strain-generating body of the mounting portion must be made extremely large, and the above method can be applied to a small-sized triaxial semiconductor force sensor. There is a problem that it is not preferable to use because it impairs the feature of being small. The present invention aims to solve the above problems.

[0008]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides a strain-generating body with a groove-shaped thin portion, and absorbs the deformation caused by uneven tightening of each screw by the thin portion, so that the semiconductor strain In addition to making it difficult to transmit to the gauge, the strain element is provided with thin, preferably three or more legs for mounting, and the strain element does not easily deform even if it is attached to a mounting surface with poor flatness. It was made to become.

[0009]

[Work]

 With the above configuration, the three thin legs provided on the flexure element are brought into contact with the mounting surface. There is a hole for a mounting screw inside each of the above-mentioned feet, and the screw is inserted into this hole, and then the screw is attached to the female screw provided on the mounting surface. However, at this time, each portion of the flexure element other than the foot portion is prevented from coming into contact with the mounting surface or other objects. When it is attached to the surface, the effect of the surface is the most influential to the flexure element when it is attached at three points, and it is stable, but it is of course possible to attach it to more than that. At this time, the groove-shaped thin portion absorbs the deformation. If it is thin, the rigidity will be lower than other parts, so that part will deform significantly, and other parts will hardly deform.

[0010]

【Example】

 FIG. 1 is a plan view showing an embodiment of a detecting portion of a triaxial semiconductor force sensor of the present invention, and FIG. 2 is a sectional view showing a mounting state. Reference numeral 1 is a strain element, 2 is a semiconductor strain gauge, 3 is an FPC for connecting to a semiconductor strain gauge and a resistivity change detection circuit of a semiconductor strain gauge (not shown), and 4 is a strain element 1 to which the semiconductor strain gauge is joined. The first annular thin portion provided in the central portion, 5 is the input shaft, 6 is a mounting screw, and 7 is a concentric first annular portion that surrounds the first annular thin portion to absorb the deformation caused by the attachment. Two annular thin-walled parts, 8 are provided in the strain-generating body 1 to mount the strain-generating body, and three legs are provided with holes through which the mounting screws 6 pass, 9 is a mounting surface, and 9a is a mounting surface 9. A recessed portion or hole is provided, in which a cover 11 described later is loosely fitted, 10 is a female screw provided on the mounting surface, and 11 is a cover for protecting the semiconductor strain gauge 2.

When fixing the semiconductor force sensor having the above structure to a predetermined mounting surface, first, as described in the above-mentioned conventional technique, the cover 11 mounted on the flexure element 1 is mounted on the mounting surface 9. It is inserted into the provided hole 9a. Then, the foot portion 8 comes into contact with the mounting surface 9. Next, as shown in FIG. 2, a screw 6 is inserted into a mounting screw hole provided in the flexure element 1, and the screw 6 is rotated to be screwed to a female screw portion 10 provided on the mounting surface 9.

The foot portion 8 should be made as thin as possible so that it is less susceptible to the flatness of the mounting surface 9 and the screw 6 should be as thin as possible to reduce the effect of tightening the screw 6. Is desirable. However, if the flexure element 1 is not firmly fixed to the mounting surface 9, it may cause a measurement error. Therefore, the thicknesses of the foot portion 8 and the screw 6 should be designed in consideration of this point.

When the screw 6 inserted into the through hole of each foot portion 8 is screwed onto the female screw 10 to fix the strain-flexing body 1 to the mounting surface 9, each screw 6 at the three positions is applied with the same force as much as possible. Must be tightened. However, even if the screws 6 are evenly tightened, the flatness of the mounting surface 9 causes the strain element 1 to be slightly deformed. If each screw 6 is tightened with such a force that the strain body 1 is not deformed at all, the strain body 1 is not firmly fixed to the mounting surface 9, which may cause a measurement error. Become one. Therefore, the deformation generated in the strain generating element 1 is absorbed by the second annular thin portion 7. That is, the second annular thin portion 7 is provided between the first annular thin portion 4 and the mounting portion of the screw 6 as shown in FIG. 2, and prevents the strain body 1 from being deformed by tightening the screw 6. The second annular thin portion 7 on the way absorbs the deformation to the first annular thin portion 4 so that the deformation of the first annular thin portion 4 can be made very small. it can.

When the deformation of the first annular thin portion 4 is very small, the zero adjustment of the display device after the attachment of the strain element 1 is almost unnecessary. Even if zero adjustment is required, the measurable range of force is not narrowed because it is negligible.

As a second embodiment, it is also possible to provide the second annular thin portion 7 as a linear groove on the strain element in a triangular shape as shown in FIG. FIG. 4 is a side view showing a state in which the flexure element 1 of the second embodiment shown in FIG. 3 is attached to the attachment surface 9. In this case, since the second annular thin portion 7 is also present between the screws 6, the forces exerted by the screws 6 on the strain-flexing body 1 do not interfere with each other, so that the first annular shape is further improved. It is possible to reduce the deformation that occurs in the thin portion 4.

FIG. 5 shows a third embodiment of the present invention. In this case, the outer peripheral portion of the flexure element 1 is entirely thin, and the foot portion 8 is provided in this portion. According to this method, since the second annular thin portion 7 is provided on the strain body 1, the second annular thin portion 7 is provided by cutting the strain body 1 from the outer peripheral direction of the strain body 1. The flexure element 1 is easy to manufacture.

6 and 7 show a fourth embodiment of the present invention. In this case, only the portion to which the screw 6 of the flexure element 1 is attached and its periphery are the second thin-walled portion 7, and the deformation caused by each screw 6 is the second attachment portion of each screw 6. The thin portion 7 absorbs each individually.

[0018]

[Effect of the device]

 As described above, in the three-axis semiconductor force sensor of the present invention, the deformation of the strain-generating body caused by mounting the strain-generating body of the detecting part on the mounting surface has a great influence on the semiconductor strain gauge. Can be made smaller. Therefore, even a strain sensor with low rigidity can be used as the detection part of a triaxial semiconductor force sensor, so a small triaxial semiconductor force sensor using a small strain element can be made. Almost no zero adjustment is required after mounting the to the mounting surface.

[Brief description of drawings]

FIG. 1 is a plan view showing an example of a strain-generating body portion of a triaxial semiconductor force sensor according to the present invention.

FIG. 2 is a cross-sectional view showing an attached state of a flexure element portion shown in FIG.

FIG. 3 is a plan view showing another embodiment of the strain-generating body portion of the triaxial semiconductor force sensor according to the present invention.

FIG. 4 is a side view showing a mounted state of a flexure element portion shown in FIG.

FIG. 5 is a partially enlarged cross-sectional view showing a third embodiment of the strain-generating body portion of the triaxial semiconductor force sensor according to the present invention.

FIG. 6 is a plan view showing a fourth embodiment of a flexure element portion of a triaxial semiconductor force sensor according to the present invention.

7 is a partial enlarged cross-sectional view showing a mounted state of the flexure element portion shown in FIG.

FIG. 8 is a plan view of a strain-generating body portion of a conventional triaxial semiconductor force sensor.

9 is a cross-sectional view showing a mounted state of the flexure element portion shown in FIG.

[Explanation of symbols]

 1. Strain element 2. Semiconductor strain gauge 4. First annular thin portion 5. Input shaft 7. Second (annular) thin portion 8. Foot

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. A semiconductor strain gauge is joined to a strain-generating body, and the deformation generated in the strain-generating body by an external force applied to an input shaft provided on the strain-generating body via a first thin portion, In a three-axis semiconductor force sensor for measuring the magnitude and direction of the external force by detecting with a semiconductor strain gauge, the strain element is provided with at least three legs for fixing to a mounting surface, and Second thin-walled portion is provided between the foot of the semiconductor strain gauge and the first thin-walled portion, and the semiconductor strain gauge is affected by the deformation of the strain-generating body generated by fixing the strain-generating body to a mounting surface. A three-axis semiconductor force sensor that is hard to reach.