JPH0615993B2 - Axial force sensor - Google Patents

Description

TECHNICAL FIELD The present invention relates to an axial force sensor that detects a component of force in a predetermined direction among forces applied to an object.

[Prior Art] In many machines, devices, etc., the magnitude of the force applied to their specific parts or the force applied to the object they handle is detected, and based on the detected value, the machine, device, etc. A means for optimally controlling is used. Further, in various academic experiments, it may be indispensable to know the magnitude of the force applied to a predetermined portion. Several axial force sensors have been proposed to detect the magnitude of such force. Hereinafter, among these proposed axial force sensors, an axial force sensor having a parallel structure having extremely excellent performance will be described.

9 (a) and 9 (b) are side views of a conventional axial force sensor. In the figure, 1 is a supporting portion, 2 is a rigid block fixed to the supporting portion 1, 3 is a rectangular through hole formed in an appropriate portion of the block 2, and 4 is a fixing for fixing the block 2 to the supporting portion 1. Parts 5 are movable parts to which a force to be detected is applied. Reference numerals 6a and 6b are thin flat plates formed by forming the through holes 3 in the block 2, and these two thin flat plates 6a and 6b are parallel to each other. Thin flat plate 6
The parallel plate structure 7 is formed by the portions centering on a and 6b. The strain gauges 8a, 8b, 8c and 8d are provided at the roots of the thin flat plates 6a and 6b and output signals according to their deformation.

In the axial force sensor having such a parallel plate structure 7, when a force Fz in the vertical direction (z-axis direction) is applied to the movable part 5, the parallel plate structure 7 becomes a thin plate as shown in FIG. 9 (b). 6a and 6b are bent into substantially the same shape and deformed. Since the thin flat plates 6a and 6b are likely to be bent and deformed with respect to a vertical force, and further, the thin flat plates 6a and 6b have the same deformation and the degree of restraining each other is small. The deformation shown in b) easily occurs. On the other hand, a direction (y
With respect to the force F _{y in the} axial direction and the force F _x in the left-right direction (x-axis direction) in the drawing, the parallel plate structures 7 have very mutual rigidity, and their deformation is difficult. Here, when a force F _z as shown in FIG. 9 (b) is applied, tensile strain is applied to the strain gauges 8a, 8b, strain gauges 8b,
A compressive strain is generated in 8c.

As described above, the parallel plate structure 7 shown in FIGS. 9A and 9B is deformed only by the force F _z in the z-axis direction, and thus the force F _z in the z-axis direction is detected with high accuracy. can do. And, of course, if the installation direction of the parallel plate structure 7 is changed to the x-axis direction and the y-axis direction, the forces F _x and F _y in the respective directions can be detected.

By the way, in the axial force sensor having such a parallel plate structure 7, when the force applied to the additional portion 5 increases and exceeds a certain value, the stress of the parallel plate structure 7 itself exceeds the elastic limit and permanent deformation occurs. , It falls into a state where it cannot be used as a sensor. In order to solve this problem, FIG. 10 or 1
The axial force sensor shown in FIG. 1 has been proposed. FIG. 10 is a side view of the proposed axial force sensor. In this figure, the same parts as those shown in FIGS. 9 (a) and 9 (b) are designated by the same reference numerals and the description thereof will be omitted. 10a, 10b, 10c, 1
Reference numeral 0d is a rectangular through hole formed in the block 2 along the vertical direction (z-axis direction). Each through hole 10a to 10d
All have the same length 1 as the length shown in FIG. 9 (a), and the width thereof is also the same as that of each through hole. Further, the through holes 10a to 10d are arranged at equal intervals on the same vertical line. 11a, 11b, 11c, 11
d and 11e are thin flat plates formed by forming the through holes 10a to 10d, and the thin flat plates 11a to 11e have the same plate thickness t as the plate thickness shown in FIG. 9 (a). The thin flat plates 11a to 11e are parallel to each other. Reference numeral 12 denotes a parallel plate structure constituted by a portion centered on each of the thin plate 11a to 11e. The places where the strain gauges 8a to 8d are installed are the root portions of the thin flat plates 11a and 11e as shown in FIGS. 9 (a) and 9 (b).

When a force F _z in the z-axis direction is applied to the movable portion 5, the parallel plate structure 12 is deformed. In this modification, the lengths and thicknesses of the thin flat plates 11a to 11e are shown in FIG. 9 (a),
Since it is the same as the thin flat plates 6a and 6b shown in (b), the deformation is in the same mode as the deformation shown in FIG. 9 (b). That is, since the distribution of stress concentrates on the root part of each thin flat plate 11a to 11e, the parallel flat plate structure 12 does not lose its characteristic of the parallel flat plate structure. Since the stress due to the deformation is shared by each of the thin flat plates 11a to 11e, the displacement amount for the same force F _z is shown in FIG. 9 (b).
It is natural that the amount of displacement becomes smaller than that in the case shown in FIG. 3, which means that the parallel plate structure 12 can be deformed with a larger force F _z while maintaining the characteristics of the parallel plate structure. It is shown. After all, this axial force sensor can detect a larger force than the conventional axial force sensor without changing the dimensions of the parallel plate structure.

FIG. 11 is a side view of another proposed axial force sensor.
In the figure, those parts that are the same as those corresponding parts in FIG. 10 are designated by the same reference numerals, and a description thereof will be omitted. 30a, 30b, 30c are through holes having a circular cross section formed in the block 2 along the vertical direction (z-axis direction), and 31a, 31b, 31c, 31d are thin holes formed by forming the through holes 30a, 30b, 30c. It is a flat plate. Since the thin flat plates 31a to 31d are formed by the circular through holes 30a to 30c, it is difficult to say that they are "flat plates" even though they are "thin walls" in reality, and the expression "thin flat plates" is used. Although not necessarily appropriate, since it has the same function (deflection function) as the thin-walled flat plate shown in FIGS. 6 (a) to (c), the term "thin-walled flat plate" is an easy-to-understand term indicating the function. Since it is conceivable, the term "thin plate" will be used below. The through holes 30a to 30c are arranged at equal intervals on the same vertical line,
The thin flat plates 31a to 31d are in parallel with each other. In this case, the parallel relationship means that each of the thin flat plates 31a to 31
This means that the thin plates are in a parallel relationship when d is idealized like the thin plates shown in FIGS. 6 (a) to 6 (c). Reference numeral 32 denotes a parallel plate structure composed of portions centering on the respective thin flat plates 31a to 31d. In this case, the terms “parallel” and “flat plate” in the parallel plate structure are used in the above meanings. Strain gauge 8a
The installation location of 8d is the root portion of the thin flat plates 31a and 31d. The operation of this axial force sensor is also the same as that of the axial force sensor shown in FIG.

[Problems to be Solved by the Invention] As described above, the axial force sensor shown in FIG. 10 and FIG. 11 is compared with the axial force sensor made of two parallel flat plates,
With the same size, a larger force can be detected. However, in such a configuration of the axial force sensor, a force component in the vertical direction acts on the movable portion 5 and at the same time a moment component is inevitably generated, so that each thin flat plate is deformed by the force component and deformed by the moment component. Occur at the same time,
There is a problem in that the force component to be detected cannot be detected accurately.

The object of the present invention is to solve the above-mentioned problems in the conventional technology,
An object is to provide an axial force sensor that can accurately detect a force component.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention is an axial force sensor that is composed of one rigid body block and detects a force component acting in a predetermined axial direction. A central rigid body portion to which a force component is applied is provided, and the rigid body portions are arranged symmetrically with respect to a plane passing through the center of the central rigid body portion and extending along the predetermined axis direction, and the rigid bodies are arranged along the surface. It is characterized in that three or more thin-walled flat plates each having a surface perpendicular to the predetermined axis direction formed by forming a plurality of through holes penetrating the block are provided.

[Operation] When a force component in the predetermined axial direction is applied to the central rigid body portion, a moment component is generated simultaneously with the force component on both sides of the central rigid body portion. However, since the moment components generated on both sides of the central rigid body portion are equal in size and opposite in direction, they cancel each other out, and the thin flat plates on both sides of the central rigid body portion are only deformed by the above components. Occurs, and it becomes possible to accurately detect this force component.

[Examples] Hereinafter, description will be given based on illustrated examples of the present invention.

FIG. 1 is a front view of an axial force sensor according to a first embodiment of the present invention. In this figure, 20 is a rigid body (central rigid body portion) of the central portion of the block 2. Reference numerals 35a _{1 to} 35c ₁ are rectangular through holes formed on one side (right side in the drawing) of the central rigid body portion 20 along the direction perpendicular to the paper surface, and are arranged on the same vertical line (vertical direction in the drawing). Reference numerals 35a _{2 to} 35c ₂ are rectangular through holes formed on the other side (left side in the drawing) of the central rigid body portion 20 along the direction perpendicular to the paper surface, and are arranged on the same vertical line (up and down direction in the drawing). Left and right through holes are central rigid body 2
They are arranged symmetrically with respect to a plane that passes through the center of 0 and is perpendicular to the paper surface. _{36a 1 ~36d 1, 36a 2 ~36d} 2 is a thin flat plate which is formed by the formation of the respective through-holes _{35a 1 ~35c 1, 35a 2 ~35c} 2. 8a ₁ ~8b ₂ is a wire strain gauges respectively provided base portion of the thin plate-thin flat plate 36a _1, 36a _2. 37 is the central rigid body portion 20
And the force is applied to the protrusion 37. Reference numeral 38 is a through hole provided below the block 2. The horizontal length of the through hole 38 is equal to that of each through hole 35a _1.
The length exceeds the left and right ends of ~ 35c ₂ . Protrusion 37
When a vertical force is applied to the central rigid body part, the thin flat plates on both sides are deformed.

In this case, a vertical force component acts on the central rigid body portion 20 on the left and right thin-walled flat plates, and at the same time, a moment component is inevitably generated. However, since the moment components generated on both sides of the central rigid body portion 20 are equal in magnitude and opposite in direction, they cancel each other out, and the force components are applied to the thin flat plates on both sides of the central rigid body portion 20. Only the deformation due to will occur.

As described above, in this embodiment, since three or more thin flat plates are configured by the through holes symmetrically arranged on both sides of the central rigid body portion, it is possible to detect a large force as in the configuration shown in FIGS. In addition to the above, it is possible to eliminate the influence of the moment component generated when the force acts, so that the acting force component can be accurately detected.

FIG. 2 is a front view of an axial force sensor according to the second embodiment of the present invention. In the figure, the same parts as those shown in FIG. 35b ₁ ′, 35b ₂ ′,
Reference numerals 35c ₁ ′ and 35c ₂ ′ are through holes formed in the block 2, respectively, and 38 ′ are through holes formed in the block 2 beyond the left and right ends of the through holes 35c ₁ ′ and 35c ₂ ′. First
The difference between the embodiment shown in the figure and this embodiment is that the former through holes are arranged on the same vertical line (vertical direction in the figure), whereas in the present embodiment, the through holes are arranged on the same vertical line. There is a point that is not done. That is, the through-holes 35b ₁ ', 35b _2' is 'is arranged at a position, offset toward the center with respect to 35a _2, through-holes 35c _1' the through hole 35a ₁ on each 3
5c ₂ ′ has through-holes 35b ₁ ′, 35 on it, respectively.
It is arranged at a position further shifted in the central direction with respect to b ₂ ′. Therefore, the through holes on both sides are arranged on a diagonal line extending downward in the center. However, the left and right through holes are the same as in the previous embodiment in that they are symmetrically arranged on a plane perpendicular to the plane of the paper passing through the center of the central rigid body portion 20. The operation and effect of this embodiment are the same as the operation and effect of the embodiment shown in FIG.

FIG. 3 is a perspective view of an axial force sensor according to a third embodiment of the present invention. In the figure, 40 is a convex block, 40a is a convex portion of the block 40, and 40b is a base of the block 40. The base 40b has the same structure as that shown in FIG. 41F _x is a thin plate group formed by a plurality of through holes penetrating from the front surface to the back surface of the convex portion 40a, and 41F _y is formed by a plurality of through holes penetrating from one side surface of the convex portion 40a to the other side surface. It is a group of thin plates. These thin plate groups 41F _x and 41F _y are the same as the parallel plate structure 12 shown in FIG. 41F _z is a thin plate group formed by two rows of through holes penetrating from the front surface to the back surface of the base 40, and is the same as the thin plate group shown in FIG.

The axial force sensor of this embodiment is a triaxial force sensor that can detect a force F _{z in} the x-axis direction, a force F _{y in the y-} axis direction, and a force F _z in the z-axis direction. That is, the force F _z is detected by the deformation of the thin plate group 41F _x , the force F _y is detected by the deformation of the thin plate group 41F _y , and the force F _z is detected by the deformation of the thin plate group 41F _z. .

As described above, in the present embodiment, the thin plate group composed of a plurality of through holes arranged in the x-axis direction and the thin plate group arranged in the y-axis direction are formed on the convex portion integrally formed on the central rigid body portion of each of the preceding examples. Since the thin flat plate group including the plurality of through holes is provided, the forces in the x-axis and y-axis directions can be simultaneously detected in addition to the force in the z-axis direction.

FIG. 4 is a perspective view of an axial force sensor according to a fourth embodiment of the present invention. In the figure, 45 is a columnar block, 46a, 46
b is a notch formed on both sides of the central portion of the block 45, and 47a and 47b are notches 46a and 4 respectively.
6b is an upper block and a lower block divided by 6b. The structure of the lower block 47b is the same as that shown in FIG. However, the through hole has a circular cross section. 48F _x is a group of thin-walled flat plates formed by a plurality of through holes having a circular cross section that penetrates from the front surface to the back surface of the upper block 47a, and 48F _y has a circular cross section that penetrates from one side surface to the other side surface of the upper block 47a. A group of thin flat plates formed by a plurality of through holes, 48F _z is the lower block 4
7b is a thin-walled flat plate group. The difference from the embodiment shown in FIG. 3 is only the shape of the block, the cross-sectional shape of each through hole, and the arrangement of the thin plate group 48F _z . The operation and effect of this embodiment are the same as those of the embodiment shown in FIG. Is the same as.

In the embodiment shown in FIGS. 3 and 4, if the convex portion 40a or the upper block 47a is separated and taken out,
Thin plate group 41F _x , 41F _y or thin plate group 48F _x ,
It is clear that a biaxial force sensor composed of 48F _y can be obtained.

FIG. 5 is a perspective view of a part of a cutting machine using an axial force sensor according to a fifth embodiment of the present invention. 20 is a work which is a work to be cut, 21 is a cutting tool for cutting the work 20, and 22 is a rigid block to which the cutting tool 21 is fixed. The rigid block 22 consists of two parts, 22A and 22B. The rigid block 22A has the same structure as that shown in FIG. Reference numeral 23 denotes a thin plate group for main component force detection formed on the rigid block 22A, and 24 denotes a thin plate group for feed component force detection formed on the rigid block 22B. Each of the thin plate groups 23 and 24 has the same structure as that shown in FIG. P ₁ is the main component force applied to the cutting tool 21, P ₂ is the feed component force applied to the cutting tool 21, and P ₃ is the back force applied to the cutting tool 21. The feed component P ₂ and the back component P ₃ are the main component P ₁
It is extremely small compared to.

In the cutting apparatus, the main component force P ₁ and the feed component force P ₂ are detected by the thin plate groups 23 and 24, respectively,
(The illustration of an axial force sensor for detecting the back force P ₃ is omitted.) Appropriate control is performed based on this inspection value.
Incidentally, when heavy cutting is performed in such a cutting device, a main component force because P ₁ is extremely large value, the thin flat plate group 24 for detecting the feed force component P _2, the feed component of force P ₂ The force (principal component force P ₁ ) in a direction other than the applied direction becomes extremely large, which may cause bending in that direction.

However, since the thin plate group 24 is also composed of a plurality of sheets,
The cross-sectional area of the thin flat plate will be several times larger than the conventional one. This means that the total width of the thin flat plates in the direction perpendicular to the direction to be detected is several times the total width of the thin flat plates of the conventional one, and the rigidity in that direction is greatly increased. Deflection in that direction is suppressed, so that even when heavy cutting is performed, it is possible to sufficiently suppress the deflection due to the main component force P ₁ . In addition, thin plate group 2
It is obvious that 3 can detect the large main component P ₁ at the time of heavy cutting without any trouble.

As described above, in this embodiment, the main component P ₁ and the feed component force P ₂ can be simultaneously detected by one axial force sensor.

FIG. 6 is a side view of an axial force sensor having a radiating plate structure. Since such a radiation plate structure is used in the embodiment shown in FIG. 7, the radiation plate structure shown in FIG. 6 will be described first. In the figure, 1 is a support portion, 60 is a rigid block supported by the support portion 1, 61 is a trapezoidal through hole provided in the block 60, 62 is a fixing portion for fixing the block 60 to the support portion 1, 63 Is a movable part to which a moment is applied. 64a and 64b are thin flat plates formed by forming trapezoidal through-holes 61 in the block 60, and these two thin flat plates 64a and 64b are positioned on the radiation of an angle θ centered on the point O. is there. The radiating plate structure 65 is configured by the portions centering on the thin flat plates 64a and 64b. 66a, 66b, 66c, 66
Symbols d are strain gauges provided at the roots of the thin flat plates 64a and 64b, respectively.

In the axial force sensor having such a radiating flat plate structure 65, when a moment acts around an axis in a direction perpendicular to the paper plane passing through the point O of the movable portion 63, the thin flat plates 64a, 64 are formed.
b is bent and deformed. The thin flat plates 64a, 64b are likely to be deformed by the moment, and the deformations are the same shape and restrain each other from each other. Therefore, the thin flat plates 64a, 6b due to the moment are deformed.
The deformation of 4b easily occurs. However, it is highly rigid and difficult to deform with respect to moments around the axis in other directions and all axial forces. Therefore, the moment about the axis perpendicular to the plane of the sheet passing through the point O can be accurately detected by the strain gauges 66a to 66d. Also in such a radiation flat plate structure 65, by forming a plurality of trapezoidal through holes, three or more thin flat plates centering on the point O can be formed, thereby detecting a larger moment. It is possible to increase the rigidity against a force and other moments.

FIG. 7 is a partially cutaway perspective view of an axial force sensor according to a sixth embodiment of the present invention. In the figure, reference numeral 70 denotes a rigid block, which is divided into the following three parts. That is, 71 is a ring-shaped upper ring portion, 72 is a ring-shaped lower ring portion, and 73 is an intermediate portion located between the upper ring portion 71 and the lower ring portion 72.
The intermediate portion 73 is formed in a substantially cross shape, and the x axis and the y axis are assumed along the cross character as shown in the figure, and the z axis is assumed in the vertical direction. 73h is the middle part 7
A central opening formed in the center of 3 through the zZ axis direction,
73C is a central block centered on the central opening 73h. The central block 73C corresponds to the central rigid body portion 20 shown in FIG. 73D ₁ and 73D ₂ are projecting portions which respectively project symmetrically from the central block 73C in the y-axis direction,
3D ₃ and 73D ₄ are projecting portions that project symmetrically from the central block 73C in the x-axis direction. Upper ring portion 71
Is connected to the upper ends of the protrusions 73D ₁ and 73D ₂ , and the lower ring part 72 is linked to the lower ends of the protrusions 73D ₃ and 73D ₄ .

In the above-mentioned block 70, the reference numeral
A thin plate group shown by 5 and a thin plate group forming a radial plate structure are formed. That is, 73M _z is a radial flat plate structure constituted by a plurality of circular through holes arranged along the periphery of the upper ring portion 71, and detects the moment about the z axis. 75F _x is a group of thin flat plates formed on both sides of the central block 73C by linearly arranging a plurality of circular through holes penetrating from the upper surface to the lower surface of the protrusions 73D ₁ and 73D _{2 in} the x-axis direction. Corresponding to the thin plate group shown in the figure,
The force in the x-axis direction is detected. 75F _y is a protrusion 73D ₃ , 7
It is a thin-walled flat plate group configured by linearly arranging a plurality of circular through holes penetrating from the upper surface to the lower surface of 3D _{4 in} the y-axis direction, and detects the force in the y-axis direction. 75F _z is a thin flat plate group configured by arranging a plurality of circular through holes penetrating from the four outer surfaces of the central block 73C (intermediate portions of the respective protruding portions) to the central opening 73h in the z-axis direction, The force in the z-axis direction is detected. 75M _x is a thin plate group that forms a radial flat plate structure configured by arranging a plurality of circular through holes penetrating from one side surface of the protruding portions 73D ₁ and 73D _{2 to} the other side surface, and detects a moment about the x-axis To do. 75M _y is a group of thin-walled flat plates that form a radial flat plate structure configured by arranging a plurality of circular through holes penetrating from one side surface of the protruding portions 73D ₃ and 73D _{4 to} the other side surface in a circular arc. Detect the moment. This embodiment, three thin flat plate group 75F _x, 75F _y, 75F _z and three thin flat plate group 75M _x to form the radiation plate structure, 75M _y, is used as the six-axis force sensor by 75M _z.

Now, it is assumed that the lower ring portion 72 is fixed to a rigid body (not shown) and a force F _y in the y-axis direction is applied to the upper ring portion 71. Then, this force F _y is _generated by the upper ring portion 71,
It is transmitted to a rigid body (not shown) through the protrusions 73D ₁ and 73D ₂ connected to it, the central block 73C, the protrusions 73D ₃ and 73D ₄ , and the lower ring portion 72 connected to the protrusions 73D ₁ and 73D ₄ . In this transmission process, the thin plate group 75M _x , 75M _y , 7
5M _z and the thin flat plate group F _x, but F _z does not occur a deformation of what such a thin flat plate group 75F _y are deformed according to the force F _y, to detect a force F _y. Even if the force F _y is large, the thin-walled flat plate group 75F _y can perform detection without any trouble because of the structure of the plurality of through holes, and other thin-walled flat plate group 75F _y can be detected.
_x , 75F _z , and the thin plate group 75M _x , 75M _y , 75M _z exhibit high rigidity and do not deform due to the structure of the plurality of through holes.

As described above, in this embodiment, the block is divided into the upper ring portion, the lower ring portion, and the middle portion, and the middle portion is provided with the opening, the central block, and the four protruding portions protruding therefrom, and the circular through hole is provided at a predetermined position. Since a plurality of parallel thin-walled flat plate groups and three radial thin-walled flat plate groups are arranged by arranging a plurality of groups, a large force in the x-axis, y-axis, and z-axis directions and the x-axis, without increasing the external dimensions, It is possible to detect a large moment around the y-axis and the z-axis, and it is possible to obtain high rigidity against a force or moment in a direction other than the direction to be detected.

8 (a), (b) and (c) are schematic views of a signal conversion device other than the strain gauge used in the axial force sensor according to the embodiment of the present invention. In FIGS. 8A and 8B, only the thin plate group for one axis and the signal conversion device for the axis are shown. 8 (a), (b),
In (c), the same parts as those shown in FIG. 10 are designated by the same reference numerals.

First, in FIG. 8 (a), 4A is a support arm extending from the fixed part 4 in an inverted L shape, 5A is a core fixed to the movable part 5 or integrally formed therewith, and 80 is a core at the center. It is a differential transformer that inserts 5A. When the force F _z is applied, the parallel plate structure 12 is deformed, the core 5A moves downward together with the movable part 5, and a signal is output from the differential transformer 80 according to the moving amount.

Next, in FIG. 8 (b), 4A 'is a sandwiching arm extending in an inverted L shape from the fixed portion 4, 81 is a piezoelectric element sandwiched between the movable portion and the sandwiching arm 4A'. is there. When the force F _z is applied, the parallel plate structure 12 is deformed and the movable part 5 moves downward. At this time, since the fixed portion 4 and the sandwiching arm 4A 'do not move, the piezoelectric element 81 is pressed by the movement of the movable portion and outputs a signal according to the pressure.

Finally, the signal conversion device shown in FIG. 11 (c) will be described. Like the axial force sensor shown in FIG. _1, 35a _{1 to} 35c ₂ are through holes formed on both right and left sides perpendicular to the plane of the drawing. By the way, in this example, through holes are formed on both sides of the left and right side surfaces of the block in the figure as well. That is, 35a ₃ and 35a ₄ are through-holes on one side and the other side that penetrate the block 2 left and right on the left and right side surfaces of the block 2, and have the same height and the same size as the through-holes 35a ₁ and 35a _2. It is formed. Therefore, when the block 2 is cut along the line XI-XI and the plane is viewed in the direction of the arrow, _two parallel grooves formed by the through holes 35a ₁ and 35a ₂ in one direction are also formed. Two parallel grooves formed by the through holes 35a ₃ and 35a ₄ are formed in the other direction orthogonal to and in the other direction, and the center is a rectangular island portion surrounded by these four grooves. _{35b 3, 35b 4, 35c 3} , 35c 4 has a similar through hole formed on the same level with the through holes 35a _3, 35a ₄ on the left and right sides of the block 2. 2C through hole 35c ₁ to 3
Shows the central portion of the square surrounded by 5c _4. Reference numeral 82 is an oil chamber formed by sealing the through hole 38, 83 is a pipe communicating with the oil chamber 82, and 84 is a hydraulic pressure gauge connected to the pipe 83. The oil chamber 82 is filled with oil. When the force Fz is applied to the movable part 37, the parallel plate structure is deformed, whereby the central part of the block 2 (the part surrounded by each through hole) moves downward, and the oil in the oil chamber 82 is deformed. The corresponding force is applied. This force is transmitted to the oil pressure gauge through the pipe 83 to form an oil chamber, is displayed by a pointer or the like, and is output as a signal corresponding to this oil pressure.

Now, the embodiments of the present invention have been described with reference to the drawings,
In the description, the shape of the through hole is described as a square or a circle. However, the shape of the through hole is not limited to these shapes, and various shapes such as an ellipse, an ellipse, and a connecting circular hole that connects two small circles with a slit can be used as long as the function as a parallel plate structure is not lost. Can be adopted. In particular, the ellipse can be easily processed by an end mill or the like when forming the through hole, and the connecting round hole can be easily formed by wire cutting or the like, which is also advantageous from the viewpoint of manufacturing. . If the strain output is too small, increase the thickness of the central part of the outermost thin flat plate (that is, form a recess in the central part of the outermost through-hole) to increase the strain on the outer surface. You can also make the change to do so. Further, the thickness of each thin flat plate of the thin flat plate group can be made different, and the size of each through hole can also be made different.

EFFECTS OF THE INVENTION As described above, one rigid block is provided with the central rigid body portion and three or more thin flat plates formed by two or more through holes symmetrically arranged on both sides thereof. ,
A force component that is even larger than the force component that can be detected by the two thin flat plates can be accurately detected without the influence of the moment.

[Brief description of drawings]

1 and 2 are front views of axial force sensors according to the first and second embodiments of the present invention, respectively, and FIGS. 3, 4, and 5 are the third, fourth, and third embodiments of the present invention. FIG. 6 is a perspective view of an axial force sensor according to a fifth embodiment, FIG. 6 is a side view of a radiating plate structure, and FIG.
The figure is a perspective view of an axial force sensor according to a sixth embodiment of the present invention,
8 (a), (b), and (c) are front views for explaining the signal conversion device of the axial force sensor, FIGS. 9 (a), (b), and 10th.
FIG. 11 and FIG. 11 are side views of a conventional axial force sensor, respectively. 2 ... Blocks, 35a ₁ , 35a ₂ , 35b ₁ , 35
b ₂ , 35c ₁ , 35c ₂ , 38 ... through-holes, 36a ₁ , 3
6a ₂ , 36b ₁ , 36b ₂ , 36c ₁ , 36c ₂ ... thin plate, 8a ₁ , 8a ₂ , 8b ₁ , 8b ₂ ... strain gauge.

Claims (1)

[Claims] 1. An axial force sensor comprising one rigid body block for detecting a force component acting in a predetermined axial direction, wherein the rigid body block is provided with a central rigid body portion to which the force component is applied, and the central rigid body portion It is formed by forming a plurality of through holes that are arranged symmetrically with respect to a plane passing through the center and extending along the predetermined axial direction on both sides of the central rigid body portion, and that pass through the rigid body block along the plane. An axial force sensor comprising three or more thin flat plates each having a surface perpendicular to the predetermined axis direction.