JPH10185711A - Load cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve the configuration of a load cell that can be manufactured easily. SOLUTION: A load cell body has a regular quadrangular prism shape. A strain-generating part 48-2 is determined by a corner opposing vertical hole 81 that is formed at each corner 38 of the load cell body, a side surface opposing vertical hole 86 that is formed for each side surface 34 of the load cell body, and a side hole 95 that is extended to a next corner opposing vertical hole 81 across an installation fixation part 49, across a corner opposing vertical hole 80, and across a side surface opposing vertical hole 86, vertical to each side surface 33 from each side surface 33 that is a plane around the load cell body. The installation fixation part 49 is in an annular shape with a load action part 47 as a center and is an annular part for surrounding the above, each strain-generating part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a load cell,
At the center there is a load acting part on which the load of the measured object acts,
The present invention relates to a load cell having a plurality of strain generating portions around a load application portion, an installation fixing portion for installing and fixing a load cell around the load application portion, and measuring a load acting on the load application portion in an axial direction.

[0002]

2. Description of the Related Art A measuring instrument for measuring the load of heavy objects such as iron ore, steel, and coiled steel plate carried on a load truck or a steel material suspended by an overhead crane or an ironworks, etc. As the strain gauge (st
rain gauge) to detect the strain when a load is applied,
2. Description of the Related Art A load cell which electrically measures a load and measures the load is used.

FIGS. 14, 15 and 16 show a load cell 10 described in Japanese Patent Publication No. 2515645, which was previously filed by the present applicant. The load cell 10 includes a load cell main body 11 made of a disc-shaped cylindrical aluminum and a strain gauge 12. The load cell main body 11 has a load acting portion 11a at the center where a load acts, and a plurality of strain generating portions 11b around the load acting portion 11a which are distorted in accordance with the magnitude of the load acting on the load acting portion 11a. In addition, there is an annular installation fixing portion 11c around the periphery for installing and fixing the load cell to a base or the like. The strain gauge 12 is adhered to each of the strain generating portions 11b. Each strain gauge 1
2 constitutes a bridge circuit.

The strain generating portion 11b is defined by vertical holes 20, 21, 22 and horizontal holes 23, 24, 25, and is present between the adjacent vertical holes 20, 21, 22 in the circumferential direction. In place. The vertical holes 20, 21, and 22 are formed at intervals of 120 degrees, and penetrate the load cell main body 11 in the axial direction. Side holes 23, 24 and 25 are also 1
It extends laterally from the circumferential surface 26 of the load cell body 11 at intervals of 20 degrees, and traverses the vertical holes 20, 21 and 22, respectively.
It extends to the vertical holes 20, 21, 22 adjacent on the circumferential direction.
The strain generating portion 11b includes vertical holes 20, 21, and 22 that are circumferentially adjacent to each other.
Between the horizontal holes 23, 24, 25 and the upper and lower surfaces of the load cell body 11.

[0005] The load cell 10 is installed and fixed on a base with an installation fixing portion 11c. When the load F acts on the load acting portion 11a, the plurality of strain generating portions 11b are distorted, and the strain gauge 12 detects the distortion of the strain generating portion 11b, and the load F is electrically measured by the bridge circuit.

The vertical holes 20, 21, 22 and the horizontal holes 23, 2
4 and 25 are both formed by drilling.

[0007]

In the load cell 10 having the above structure, the load cell main body 11 has a cylindrical shape, so that the load cell main body 11 is hardly chucked, and thus drilling is difficult. In particular, side hole 2
Drilling for forming the holes 3, 24, and 25 is difficult because the angle of the load cell body 11 cannot be easily set.
It was more difficult than drilling to form 1,22.

Further, when drilling the lateral holes 23, 24 and 25, it is necessary to make a cut from the curved circumferential surface 26 and in a direction deviated from the radial direction of the load cell main body 11. But slippery and difficult to process. Therefore, it was difficult to manufacture the load cell 10 having the above configuration.

Therefore, an object of the present invention is to provide a load cell which has solved the above-mentioned problems.

[0010]

According to a first aspect of the present invention, there is provided a load operating portion in which a load of an object to be measured is applied at a center portion, and a load acting on the load operating portion is provided around the load applied portion. A load cell body having a plurality of strain generating portions that are distorted in accordance with the size and having an installation fixing portion around which the load cell is installed and fixed to a base or the like; In the load cell comprising a strain gauge for detecting the strain, the load cell main body has a regular polygonal prism shape, and each of the strain-generating portions is one for each corner of the regular polygonal prism load cell body. A square opposed vertical hole formed in the direction of the axis of the load cell main body, and a side opposed vertical hole formed in the direction of the axis of the load cell main body for each planar side surface of the load cell main body. , From each flat side surface of the load cell body to the side surface. Parallel to the side surface fit, across the sides facing longitudinal hole across the angle opposite longitudinal hole across the installation fixing unit, in which a configuration which is defined by the transverse holes extending up to the next corner opposing longitudinal hole.

The invention according to a second aspect of the present invention has a load acting portion at the center portion on which a load of an object to be measured acts, and is distorted around the load acting portion in accordance with the magnitude of the load acting on the load acting portion. A load cell body having a plurality of strain generating portions, and having a mounting fixing portion around which the load cell is mounted and fixed to a base or the like, and a strain which is attached to the strain generating portion and detects a strain generated in the strain generating portion. In a load cell comprising a gauge, the load cell main body has a regular polygonal prism shape, and each of the strain-generating portions has an axis direction of the load cell main body, one for each corner of the regular polygonal prism load cell body. An opposed vertical hole formed through the load cell body; a side opposed vertical hole formed through the load cell body in the direction of its axis for each planar side surface of the load cell body; From each side of the shape parallel to the side adjacent to the side Is obtained by a structure which is defined by the lateral hole extends to the side opposite longitudinal hole across the angle opposite longitudinal hole across the installation fixing unit.

According to a third aspect of the present invention, there is provided a load acting portion at a center portion on which a load of an object to be measured acts, and the load is distorted around the load acting portion according to the magnitude of the load acting on the load acting portion. A load cell body having a plurality of strain generating portions, and having a mounting fixing portion around which the load cell is mounted and fixed to a base or the like, and a strain which is attached to the strain generating portion and detects a strain generated in the strain generating portion. In a load cell comprising a gauge, the load cell main body has a regular polygonal prism shape, and each of the strain-generating portions has an axis direction of the load cell main body, one for each corner of the regular polygonal prism load cell body. Two adjacent opposed vertical holes formed so as to penetrate through the installation fixing portion and from the planar side surfaces of the load cell main body in parallel to the side surfaces adjacent to the side surfaces. With the horizontal hole extending to the next corner-facing vertical hole. It is obtained by a structure which is defined.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the installation fixing portion is an annular surface centered on the load acting portion. According to a fifth aspect of the present invention, there is provided a load applying portion in which a load of an object to be measured is applied at a central portion, and a plurality of protrusions distorted around the load applying portion in accordance with the magnitude of the load applied to the load applying portion. A load cell body having a distorted portion and having an installation fixing portion for installing and fixing the load cell to a base or the like around the periphery, and a strain gauge attached to the distorted portion and detecting a strain generated in the distorted portion. In the load cell, the load cell main body is formed of a square prism, and each of the strain generating portions is formed so as to penetrate the square prism one by one at each corner of the square prism in the direction of the axis thereof. A vertical hole, a side-facing vertical hole formed by penetrating the square prism in the direction of its axis for each side surface of the square prism,
From each side surface, which is a plane around the square prism, to the side surface adjacent to the side surface, in parallel with the side surface adjacent to the side surface, cross the installation fixing portion, cross the square opposing vertical hole, cross the side opposing vertical hole, and extend to the next square opposing vertical hole. The installation fixing portion has a ring shape centered on the load acting portion and is a ring portion surrounding each strain generating portion.

[0014]

FIG. 1 shows a load cell 30 according to a first embodiment of the present invention. The load cell 30 generally includes a load cell main body 31 made of aluminum and eight strain gauges 32-1 to 32-8.

FIGS. 2, 3A, 3B, 3C and 4 show the load cell body 31. FIG. As shown in each figure,
The load cell body 31 has a square prism shape having a side length a of about 60 mm and a height (thickness) b of about 20 mm, and four flat side faces 33, 34, 35, 36, 4 It has three corners 37,38,39,40. X is side surface 33,
35 is a direction parallel to 35, Y is a direction parallel to the side surfaces 34 and 36, and Z is a height direction (axial direction) of the load cell body 31.

The load cell main body 31 has a load acting portion 37 at the center thereof on which a load acts, and eight load distorting portions around the load acting portion 47 depending on the magnitude of the load acting on the load acting portion 47. It has distortion parts 48-1 to 48-8,
An installation fixing section 49 for installing and fixing the load cell to a base or the like is provided around the outside outside of 8-1 to 48-8. As shown in FIGS. 6A and 6B, the eight strain gauges 32-1 to 32-8 are adhered to the respective strain-generating portions 48-1 to 48-8 one by one. The strain gauges 48-1 to 48-8 are appropriately connected to form a bridge circuit 50 shown in FIG.

As shown in FIGS. 2 and 3B, the load acting portion 47 has a substantially cylindrical shape, and
1 includes a convex portion 52 on the upper surface 51 side, a convex portion 54 on the lower surface 53 side of the load cell main body 31, and a screw hole 55 penetrating the convex portion 52 and the convex portion 53 in the axis (Z) direction. Convex part 52
Are relatively convex from the bottom surface 57 of the annular groove 56. The convex portion 52 is relatively convex from the bottom surface 59 of the annular groove 58. The upper end surface 60 of the load acting portion 47 is slightly lower than the upper surface 62 of the annular base 61. The lower end surface 63 of the load acting portion 47 is slightly recessed from the surface 65 of the annular base 64. The upper end surface 60 of the load acting portion 47 is
It may be the same height as the upper surface 62 of the first.

The height of the projection 52 is slightly longer than the height of the projection 54. An annular plate portion 72 between the bottom surface 53 and the bottom surface 59
Is slightly larger than the diameter d3 of the lateral hole 95. The annular pedestal 61 includes the annular groove 56 and the load cell body 31.
And between the triangular surface portions 66 of the respective corners 37 to 40 of the upper surface 51 of the first embodiment. The annular base 64 is formed of a triangular surface 6 having corners 37 to 40 of the annular groove 58 and the lower surface 53 of the load cell body 31.
7 and exists.

As shown in FIGS. 2 and 3B, the installation fixing portion 49 includes an annular base 64, an annular base 61, and through holes 68 to 71. Each of the through holes 68 to 71 has three corners.
7, 38, 39, and 40, and penetrate the annular base 61 and the annular base 64.

As shown in FIGS. 2 and 3B, the strain generating portions 48-1 to 48-8 are formed in the annular plate portion 72 having a plurality of holes. The remaining portion of the annular plate portion 72 which is not removed by the hole is the strain generating portion 48-1.
48-8. The annular plate 72 (the load cell main body 31) has the following vertical holes and horizontal holes. The vertical hole is a hole in the Z direction, and the horizontal hole is a hole along the XY plane.

Numerals 80, 81, 82, and 83 are vertical holes opposed to each other, each having a diameter d1, and provided at each of the corners 37, 38, 39, and 40 so as to face each of the corners 37, 38, 39, and 40. . The corner-facing vertical holes 80 and 82 are located on a diagonal line 84 connecting the corners 37 and 39 and at positions near the corners 37 and 39, that is, at positions closer to the outer periphery of the annular plate portion 72. , Penetrates the annular plate portion 72 in the Z direction. The corner-facing vertical holes 81 and 83 are diagonal lines 8 connecting the corners 38 and 40, respectively.
5 and near the corners 38 and 40, that is, at a position closer to the outer periphery of the annular plate 72, and penetrates the annular plate 72 in the Z direction. The square facing vertical hole 80 and the square facing vertical hole 83, and the square facing vertical hole 81 and the square facing vertical hole 82
They are respectively located on lines 91 and 93 parallel to the X axis. The corner-facing vertical holes 80 and 81 and the corner-facing vertical holes 82 and 83 are located on lines 90 and 92 parallel to the Y axis, respectively.

Reference numerals 86, 87, 88, 89 denote vertical holes opposed to the side surfaces, each having a diameter d2. The diameter d2 is equal to the above-mentioned angled vertical hole 8.
It is equal to the diameter d1 such as 0. The side facing vertical hole 86 is
Are formed in the annular plate portion 72 at an intermediate position between the square opposed vertical hole 80 and the square opposed vertical hole 81,
The annular plate 72 penetrates in the Z direction. Square facing vertical hole 80
, The side facing vertical hole 86 and the corner facing vertical hole 81 are aligned on a line 90 parallel to the Y axis.

The side facing vertical hole 87 faces the center of the side surface 35, and is formed in the annular plate portion 72 at a position intermediate between the square facing vertical hole 81 and the square facing vertical hole 82.
2 in the Z direction. The square opposed vertical hole 81, the side opposed vertical hole 87, and the square opposed vertical hole 82 are formed by a line 9 parallel to the X axis.
1 above.

The side facing vertical hole 88 faces the center of the side surface 36 and is formed in the annular plate portion 72 at a position between the corner facing vertical hole 82 and the corner facing vertical hole 83 in the annular plate portion 72.
2 in the Z direction. The square opposed vertical hole 82, the side opposed vertical hole 88, and the square opposed vertical hole 83 are formed by a line 9 parallel to the Y axis.
2 above.

The side facing vertical hole 89 faces the center of the side surface 33 and is formed in the annular plate portion 72 at a position intermediate between the square facing vertical hole 80 and the square facing vertical hole 83.
2 in the Z direction. The square opposed vertical hole 80, the side opposed vertical hole 89, and the square opposed vertical hole 83 are formed by a line 9 parallel to the X axis.
3 on top.

Reference numerals 95, 96, 97, 98 denote lateral holes having a diameter d3. The center of the horizontal hole 95 coincides with the above-described line 90, and extends from the side surface 33 to the inside of the load cell main body 31 (annular plate portion 72) in the Y1 direction perpendicularly to the side surface 33. , Enters the annular plate portion 72, crosses the vertical square hole 80, crosses the vertical vertical hole 86, and terminates at the position of the vertical vertical hole 81.

The center of the lateral hole 96 coincides with the above-mentioned line 91, and extends in the X2 direction from the side surface 34 to the inside of the load cell body 31 (annular plate portion 72) perpendicularly to the side surface 34. It traverses the fixing portion 49, enters the annular plate portion 72, traverses the square opposing vertical hole 81, traverses the side opposing vertical hole 87, and terminates at the position of the square opposing vertical hole.

The center of the horizontal hole 97 coincides with the above-mentioned line 92, and extends in the Y2 direction from the side surface 35 to the inside of the load cell body 31 (annular plate portion 72) perpendicular to the side surface 35. It crosses the fixing portion 49 and enters the annular plate portion 72, crosses the corner opposed vertical hole 82, crosses the side opposed vertical hole 88, and terminates at the position of the corner opposed vertical hole 83.

The center of the horizontal hole 98 coincides with the above-mentioned line 93, and extends in the X1 direction from the side surface 35 to the inside of the load cell body 31 (annular plate portion 72) perpendicularly to the side surface 35. It crosses the fixing portion 49 and enters the annular plate portion 72, crosses the corner opposed vertical hole 83, crosses the side opposed vertical hole 89, and terminates at the position of the corner opposed vertical hole 80.

The diameter d3 of the lateral hole 95 is smaller than the thickness c of the annular plate 72 by about 1 mm. Strain-flexing parts 48-1 to 48-8
Are formed in the annular plate portion 72 at the above-described square opposed vertical holes 80, 81,
82, 83, side facing vertical holes 86, 87, 88, 89 and horizontal holes 95, 96, 97, 98 are formed by the portions which are not removed. Strain generating parts 48-1 to 48
As shown in FIG. 4, lines -8 to -8 are drawn in each image when a well is drawn around the load acting portion 47 as shown in FIG.
8 above.

The strain-flexing portion 48-1 is located on the line 105, and as shown enlarged in FIG. 5, the upper beam 100 extending in the X direction, and approximately the lower dimension of the upper beam 100. The lower beam 101 also extends in the X direction at the position c, and has a so-called parallel spring structure.

The upper beam 100 and the lower beam 101 are formed by portions which are not cut off by the corner opposed vertical holes 80, the side opposed vertical holes 86, and the horizontal holes 95. Upper beam 100
Is a length l1 having a minimum width w1 and a minimum thickness t1 at the center.
It is a beam. The lower beam 101 is the same as the upper beam 100. The minimum width w1 is determined by the diameter d1 of the vertical square hole 80, the diameter d2 of the vertical vertical hole 86, and the distance between the vertical square hole 80 and the vertical vertical hole 86. The minimum thickness t1 is the thickness of the annular plate portion 72.
And the diameter d3 of the lateral hole 95. Length l1
Are the diameter d1 of the vertical hole 80 and the diameter d of the vertical hole 86.
Determined by 2. The upper beam 100 has a minimum width w1 of about 4 mm, a minimum thickness t1 of about 0.5 mm, and a length l1 of about 8 mm.

Further, the bottom surfaces 57 and 59, and the corner opposed vertical holes 8
0, the finish roughness accuracy of the inner surface of the side facing vertical hole 86 and the horizontal hole 95 is 3S at the maximum height Rmax, and the finish roughness accuracy of the surface of the upper beam 100 and the lower beam 101 is the maximum height Rma.
x is 3S. As shown in FIG. 8, the upper beam 100 and the lower beam 101 are elastically bent such that the X1 end is a fixed end and the X2 end is displaced in the Z2 direction.

The strain-flexing portion 48-2 is formed of a parallel beam extending in the X direction which is not cut off by the corner opposed vertical hole 81, the side opposed vertical hole 86, and the horizontal hole 95.
Located on top. The strain-flexing portion 48-3 has a vertical opposed vertical hole 81.
It is formed of a parallel beam extending in the Y direction that has not been removed by the vertical hole 87 and the horizontal hole 96 facing the side, and is located on the line 107. The strain-flexing portion 48-4 is formed of a parallel beam extending in the Y direction that has not been cut off by the corner opposed vertical hole 82, the side opposed vertical hole 87, and the horizontal hole 96, and is located on the line 108. The strain-flexing portion 48-5 is formed of a parallel beam extending in the X direction that has not been cut off by the corner opposed vertical hole 82, the side opposed vertical hole 88, and the horizontal hole 97, and is located on the line 106. Flexure section 48-6
Is formed by a parallel beam extending in the X direction which is not cut off by the corner opposed vertical hole 83, the side opposed vertical hole 88, and the horizontal hole 97, and is located on the line 105. Flexure section 4
8-7 is a vertical hole 83 facing the corner, a vertical hole 89 facing the side surface, and a horizontal hole 9
8 and is formed of a parallel beam extending in the Y direction that has not been scraped off, and is located on the line 108. The strain-flexing portion 48-8 is formed by a parallel beam extending in the Y direction which is not cut off by the corner opposed vertical hole 80, the side opposed vertical hole 89, and the horizontal hole 98, and is located on the line 107.

The strain generating parts 48-1 to 48-8 are arranged around the load acting part 47. The strain generating part 48-1 and the strain generating part 4
8-6 are aligned on line 105. Strain generating part 48-
2 and the strain-flexing portion 48-5 are aligned on the line 106.
The strain generating part 48-3 and the strain generating part 48-8 are aligned on the line 107. The strain generating portion 48-4 and the strain generating portion 48-7 are aligned on the line 108.

When each of the strain generating portions 48-1 to 48-8 bends due to a load acting on the load application portion 47, the upper surface thereof is pulled toward the installation fixing portion 49 and compressed toward the load application portion 47. Is done. FIG. 6 shows the strain gauges 32-1 to 32-8.
As shown in FIG.
8-8 are adhered one by one along the beam.

Each of the strain gauges 32-1 to 32-8 is formed by printing a fine electric resistance foil pattern on an epoxy resin film. When the strain is distorted in the tensile direction, the electric resistance pattern becomes thin and the resistance value becomes small. When the resistance is increased and the material is distorted in the compression direction, the electric resistance pattern becomes thick and the resistance value decreases.

As shown in FIGS. 8 and 9, the center of each of the strain gauges 32-1, 32-3, 32-5, and 32-7 is the strain-generating portion 48 so as to detect the compression strain. −
The dimension δ is shifted from the center (the above-mentioned lines 90 to 93) such as 1, 48-3, etc., toward the load application portion 47 side.

As also shown in FIGS. 8 and 9,
As for the strain gauges 32-2, 32-4, 32-6, and 32-8, the centers of the strain gauges are set so as to detect the tensile strain.
The dimension δ is shifted from the center of 8-2, 48-4, etc. (the above-mentioned lines 90 to 93) toward the installation fixing portion 49.

The above-mentioned dimension δ is equal to the diameter d1 of the square opposed vertical hole 80.
(Or the diameter d2 of the side facing vertical hole 86) is 15 to 16%. Each strain gauge is connected so as to form a bridge circuit 50 shown in FIG. Strain gauges 32-1 and 32-3 for detecting compressive strain are connected in series, and strain gauges 32-5 and 32-7 for detecting compressive strain are also connected in series, and both are opposed to each other. doing. Strain gauges 32-2 and 32 for detecting tensile strain
-4 are connected in series, and strain gauges 32-6 and 32-8 for detecting tensile strain are connected in series,
Both are facing.

As shown in FIG. 1, the annular grooves 52 and 58 of the load cell body 31 are covered with an annular lid 110. Further, the connector 111 is incorporated in the lateral hole 96. The connector 111 is connected to the output terminal 112, and is exposed at the opening of the horizontal hole 96. The connection may be made directly without using the connector 111.

Next, the use of the load cell 30 having the above configuration is described.
The operation will be described. As shown in FIG. 1, the load cell 30 has the installation fixing portion 49 fixed on the base 121 with bolts 120 penetrating through holes 68 to 71. Further, the load receiving member 122 is screwed into the screw hole 55 so that
, And the connector 123 at the end of the cord of the measuring instrument (not shown) is connected to the connector 111. As a result, the load cell 30 enters a use state.

When a load acts on the load receiving member 122,
In the load cell main body 31, the load acting portion 47 is installed and fixed
Deformed to sink. The strain generating portion 48-1 and the strain generating portion 48-6 are distorted into a substantially parallelogram shape as shown in an exaggerated manner in FIG. 8, the strain gauge 32-1 detects a compressive strain, and the strain gauge 32-6 detects a tensile strain. Detect distortion. The strain generating portions 48-2 and 48-5 are distorted in a substantially parallelogram shape as shown in an exaggerated manner in FIG. 9, the strain gauge 32-1 detects tensile strain, and the strain gauge 32-5 compresses. Detect distortion.

The change in the resistance value of each of the strain gauges 32-1 to 32-8 is applied to a predetermined calculation formula, and the load applied to the load receiving member 122 is displayed on a measuring instrument (not shown). Next, features of the load cell 30 having the above configuration will be described. Since the shape of the load cell body 31 is a square prism, chucking to an NC milling machine, a lathe or the like is easy.

A horizontal hole 9 for forming the strain-generating portion 48-1 and the like
5, 96, 97 and 98 are the side surfaces 33, 34 and 3 respectively.
5 and 36, it is formed perpendicular to the side surfaces 33, 34, 35 and 36. For this reason, when drilling the horizontal holes 95, 96, 97, and 98, the position of the load cell main body 31 is easier to position than when drilling holes in the side surface of the circle, and the drilling is started. Occasionally, the tip of the drill does not slip, and the lateral holes 95, 96, 97, 98 can be formed easily and accurately.

Therefore, the load cell 30 can be manufactured with a higher yield than in the past and at a processing cost of about half that in the past. Further, the portion that is in contact with the base 121 is an annular installation fixing portion 49, and the triangular portion of the corner is the base 12.
Since the load cell 30 is floating above 1, the load can be measured with sufficient accuracy even if the load cell 30 is not a cylinder but a square prism. The measurement error is 0. 0 of the rated load of the load cell 30.
02% or less.

Further, the strain gauges 32-1 to 32-8 are bonded only to the upper beam 100 for each of the strain generating portions 48-1 to 48-8. Therefore, the load can be measured with higher accuracy than when four strain gauges are separately bonded to the upper beam and the lower beam. Next, a modified example will be described.

As a material of the load cell body 31, nickel chromium molybdenum steel can be used. Vertical hole 86 facing the side
May be different from the diameter d1 of the square opposing vertical hole 80 or the like.

Next, another embodiment of the present invention will be described. FIG. 10 shows a load cell 130 according to a second embodiment of the present invention. The load cell 130 has a load cell body 131 having a regular triangular prism shape. The load cell main body 131 has a square opposed vertical hole 132, side opposed vertical holes 133 and 134, and a horizontal hole 135.
Is formed. Two side facing vertical holes 133 and 134 are provided for each side 136. Side hole 135 is side 1
Starting at 36, it extends parallel to the side next to this side 136, and has a square opposing vertical hole 132, side opposing vertical holes 133, 134
Across the road to the next corner-facing vertical hole. A strain generating portion 137 is formed between the vertical holes 133 and 134 facing the side surface, and the strain gauge 32 is bonded to the strain generating portion 137. Strain gauge 3
2 is a bridge circuit similar to the above.

FIG. 11 shows a load cell 140 according to a third embodiment of the present invention. The load cell 130 has a regular hexagonal prism-shaped load cell body 141. Load cell body 14
1 has a corner opposed vertical hole 142, a side opposed vertical hole 143, and a horizontal hole 145. The side hole 145 starts from the side surface 146, extends parallel to the side surface adjacent to the side surface 146, crosses the corner opposed vertical hole 142, and reaches the side opposed vertical hole 143. A portion between the square opposed vertical hole 142 and the side opposed vertical hole 143 serves as a strain generating portion 147, in which the strain gauge 32 is provided.
Is adhered. The strain gauge 32 forms a bridge circuit as described above.

FIG. 12 shows a load cell 150 according to a fourth embodiment of the present invention. The load cell 150 has a regular octagonal prism-shaped load cell body 151. Load cell body 15
In FIG. 1, a corner opposed vertical hole 152 and a horizontal hole 155 are formed. Since the length of the side surface 156 is short, no vertical hole facing the side surface is formed. The side hole 155 starts from the side surface 156,
It extends parallel to the side adjacent to this side 156 and crosses the corner opposed vertical hole 152 to the next corner opposed vertical hole.
A strain generating portion 157 is formed between the adjacent corner opposed vertical holes 152, and the strain gauge 32 is adhered to the strain generating portion 157. Strain gauge 3
2 is a bridge circuit similar to the above.

FIG. 13 shows a load cell 150A according to a fifth embodiment of the present invention. The load cell 150A is a modified example of the load cell 150 of FIG. 12, in which lateral holes 155 are formed in every other side surface 156.

[0053]

As described above, according to the first, second, and third aspects of the present invention, the load cell main body is formed of a regular polygonal prism, and the lateral holes are flat surfaces around the regular polygonal prism. Drilling to form a side hole should be started on a flat surface instead of a curved surface.The work of chucking the load cell main body to the machine tool and processing the side hole is performed when the load cell main body is a cylinder. As a result, the load cell can be manufactured with a lower processing cost than the conventional one and at a high yield.

According to the first and second aspects of the present invention, since the strain-flexing portion is formed between the square opposed vertical hole and the side opposed vertical hole,
When the length of each side of the load cell body is long, for example, in the case of a small number of corners, a regular triangular prism, or a regular square prism, a sufficiently deformable strain-generating portion can be formed. According to the second aspect of the present invention, since the horizontal hole crosses the corner-facing vertical hole and extends to the side-facing vertical hole, the strength of the load cell body can be prevented from being unnecessarily reduced.

Since the third aspect of the present invention does not have the vertical hole facing the side surface, it is effective when applied to a load cell body having a short side, for example, a regular octagonal prism load cell body.
According to the fourth aspect of the present invention, since the installation fixing portion is configured to be an annular surface centered on the load acting portion, the influence of the load cell body being a regular polygonal prism is minimized, and the load is accurately measured. I can do it.

According to the fourth aspect of the present invention, it has the shape of a regular square pole, and can be formed by cutting the side hole vertically to the side.
Therefore, the lateral hole can be more easily and accurately drilled, so that it can be manufactured at a low processing cost and the load can be measured with high accuracy.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of a load cell according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a load cell main body.

FIG. 3 is a view showing a load cell main body of FIG. 2;

FIG. 4 is a plan view of the load cell main body of FIG. 2;

FIG. 5 is an enlarged view showing one strain generating portion.

FIG. 6 is a diagram showing the load cell of FIG. 1 with a lid removed.

FIG. 7 is a diagram showing a bridge circuit.

FIG. 8 is an exaggerated view showing a state of distortion of a strain generating part when a load cell is used.

FIG. 9 is a diagram exaggeratingly showing a state of distortion of a strain generating portion when a load cell is used.

FIG. 10 is a plan view of a load cell according to a second embodiment of the present invention.

FIG. 11 is a plan view of a load cell according to a third embodiment of the present invention.

FIG. 12 is a plan view of a load cell according to a fourth embodiment of the present invention.

FIG. 13 is a plan view of a load cell according to a fifth embodiment of the present invention.

FIG. 14 is a partially cutaway perspective view of one example of a conventional load cell.

FIG. 15 is a plan view of the load cell of FIG. 14;

FIG. 16 is a front view of the load cell of FIG. 14;

[Explanation of symbols]

 30, 130, 140, 150, 150A Load cell 31, 131, 141, 151 Load cell body 32-1 to 32-8 Strain gauge 33 to 36, 136, 146, 156 Planar side surface 37 to 40 Angle 47 Load acting portion 48 -1 to 48-8, 137, 147, 157 Strain-flexing part 49 Installation fixing part 50 Bridge circuit 51 Upper surface 52, 54 Convex part 53 Lower surface 55 Screw hole 56, 58 Groove 57, 59 Bottom surface 60 Upper end surface 61, 64 Ring base Part 62 Upper surface 63 Lower end surface 65 Surface 66, 67 Triangular surface part 68-71 Through hole 72 Annular plate part 80-83, 132, 142, 152 Square opposing vertical hole 84, 85 Diagonal line 86-89, 133, 134, 143 Side opposing vertical hole 90-93 line 95-98, 135, 145, 155 Side hole 100 Upper beam 101 Lower beam 105-108 Wire 110 Lid 111 Connector 112 Output terminal 120 Bolt 121 Base 122 Load receiving member 123 Connector

Claims (5)

[Claims] A plurality of strain-generating portions having a load acting portion at a central portion on which a load of an object to be measured acts, and distorted around the load acting portion in accordance with the magnitude of the load acting on the load acting portion. Has,
A load cell comprising a load cell main body having an installation fixing portion for mounting and fixing the load cell to a base or the like, and a strain gauge attached to the strain generating portion and detecting a strain generated in the strain generating portion. The main body has a regular polygonal prism shape, and each of the strain generating portions is formed so as to penetrate in the direction of the axis of the load cell body, one for each corner of the regular polygonal prism load cell body. An opposing vertical hole, a side opposing vertical hole formed through the load cell main body in the direction of its axis for each planar side surface of the load cell main body, and adjacent to the side surface from each flat side surface of the load cell main body. In parallel with the mating side surface, crossing the installation fixing portion, traversing the square opposed vertical hole, traversing the side opposed vertical hole, and having a configuration defined by a horizontal hole extending to the next square opposed vertical hole. Do low Cell. 2. A plurality of strain-generating portions having a load acting portion at a center portion on which a load of an object to be measured acts, and distorted around the load acting portion in accordance with the magnitude of the load acting on the load acting portion. Has,
A load cell comprising a load cell main body having an installation fixing portion for mounting and fixing the load cell to a base or the like, and a strain gauge attached to the strain generating portion and detecting a strain generated in the strain generating portion. The main body has a regular polygonal prism shape, and each of the strain generating portions is formed so as to penetrate in the direction of the axis of the load cell body, one for each corner of the regular polygonal prism load cell body. An opposing vertical hole, a side opposing vertical hole formed through the load cell main body in the direction of its axis for each planar side surface of the load cell main body, and adjacent to the side surface from each flat side surface of the load cell main body. A load cell, wherein the load cell is defined by a horizontal hole extending across the installation fixing portion and across the corner-facing vertical hole to the side-facing vertical hole in parallel to the mating side surface. 3. A plurality of strain-generating portions having a load acting portion at a central portion on which a load of an object to be measured acts, and distorted around the load acting portion in accordance with the magnitude of the load acting on the load acting portion. Has,
A load cell comprising a load cell main body having an installation fixing portion for mounting and fixing the load cell to a base or the like, and a strain gauge attached to the strain generating portion and detecting a strain generated in the strain generating portion. The main body has a regular polygonal prism shape, and each of the strain generating portions is formed so as to penetrate in the direction of the axis of the load cell body one by one at each corner of the regular polygonal prism load cell body. Two matching opposed vertical holes, and extending from the planar side surface of the load cell body to the side adjacent to the side surface, parallel to the installation fixing portion, across the square opposed vertical hole, and to the next square opposed vertical hole. A load cell having a configuration defined by the horizontal hole. 4. The load cell according to claim 1, wherein the installation fixing portion is an annular surface centered on the load acting portion. 5. A plurality of strain-generating portions having a load acting portion at a central portion on which a load of an object to be measured acts, and distorted around the load acting portion in accordance with the magnitude of the load acting on the load acting portion. Has,
A load cell comprising a load cell main body having an installation fixing portion for mounting and fixing the load cell to a base or the like, and a strain gauge attached to the strain generating portion and detecting a strain generated in the strain generating portion. The main body has a regular quadrangular prism shape, and each of the strain generating portions is formed so as to penetrate in the direction of the axis of the load cell main body, one at each corner of the regular polygonal prism load cell body. A vertical hole, a side facing vertical hole formed by penetrating the load cell main body in the direction of its axis for each planar side surface of the load cell main body, and being adjacent to the side surface from each planar side surface of the load cell main body. In parallel to the side surface, it is defined by a horizontal hole that traverses the installation fixing portion, traverses the corner opposed vertical hole, traverses the side opposed vertical hole, and extends to the next corner opposed vertical hole. Load action An annular around the load cell, characterized in that it has a configuration which is an annular portion surrounding the respective strain generating portions.