JP2010210461A - Force sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a force sensor reduced in variations of its output corresponding to sensitivity thereof or force applied thereto, having a simple and small-sized structure with a reduced manufacturing cost. <P>SOLUTION: Since the force sensor includes a position adjustment means 50 for a magnetic sensor 5, the position of a magnetic circuit 45 is adjustable relative to the magnetic sensor 5 after assembly. In assembling a shaft 1 and a housing 3 with an elastic member 2 put therebetween, the position of the magnetic sensor 5 in the magnetic circuit 45 is adjustable even if the assembly is performed with the magnetic circuit 45 and the magnetic sensor 5 displaced relative to each other owing to the displacement of the shaft 1 relative to the housing 3 caused by elastic deformation, etc. of the elastic member 2. Accordingly, the force sensor 10 can be acquired which is reduced in variations of its output corresponding to sensitivity thereof or force applied thereto. Further, the force sensor 10 can be acquired having a simple and small-sized structure with a reduced manufacturing cost since a permanent magnet dispensing with wiring is used in a magnetic field generator 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a force sensor used for a robot or the like.

The force sensor is attached to, for example, a hand part at the tip of the arm part of the robot, and is used to detect a force applied to the hand part. The robot is applied to operations such as assembly of electronic components. Since the assembly process of electronic components is diverse and requires a large number of robots, a force sensor with a simple structure and reduced manufacturing cost is required.
As a force sensor, there is a structure in which a transmission coil substrate and a reception coil substrate are arranged in parallel with a predetermined interval with a supporting rubber that is an elastic member interposed therebetween. When force is applied to the transmission coil substrate and the reception coil substrate, the distance between them changes, and the electromotive current generated in the reception coil increases or decreases. There is known an electromagnetic induction type that detects the increase / decrease in the electromotive force, measures the amount of displacement, and measures the force applied from the compression characteristics of the supporting rubber (see, for example, Patent Document 1).

JP 2002-82006 A (2 pages, FIGS. 1 to 3)

However, in the electromagnetic induction type, after the transmission coil and the reception coil are formed on the transmission coil substrate and the reception coil substrate, respectively, when the transmission coil substrate and the reception coil substrate are arranged in parallel with the elastic member interposed therebetween, When the interval is not constant, it is difficult to adjust the sensitivity balance after manufacturing the force sensor. Therefore, the output corresponding to the sensitivity and applied force varies.
Further, in the electromagnetic induction type, wiring to the transmission coil and the reception coil is required, the structure is complicated, and it is difficult to reduce the manufacturing cost.

  SUMMARY An advantage of some aspects of the invention is to solve at least one of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
A first substrate having a magnetic circuit formed by a magnetic field generator having a yoke, a second substrate having a magnetic sensor crossing the magnetic circuit, and between the first substrate and the second substrate. A force sensor comprising: an elastic member that is elastically deformed by a load applied therebetween, and at least one of a position adjusting unit of the magnetic sensor and a permeance adjusting unit of the yoke.

  According to this application example, since at least one of the position adjusting means of the magnetic sensor or the permeance adjusting means of the yoke constituting the magnetic circuit is provided, the relative position of the magnetic circuit and the magnetic sensor after assembly or the magnetic circuit At least one of the adjustments is possible. When the first base and the second base are assembled through the elastic member, the relative position between the first base and the second base is shifted due to elastic deformation of the elastic member, etc. Even when the magnetic sensor is assembled with a relative position shifted, at least one of the position of the magnetic sensor in the magnetic circuit and the magnetic circuit can be adjusted. Therefore, a force sensor with little variation in output according to sensitivity and applied force can be obtained.

[Application Example 2]
In the force sensor, the shape of the yoke forms the magnetic circuit such that an output of the magnetic sensor and a moving distance of the magnetic sensor moving in the magnetic circuit by the load are in a proportional relationship. Force sensor characterized by its shape.
In this application example, the shape of the yoke is formed so that the magnetic circuit has a proportional relationship between the output of the magnetic sensor and the moving distance of the magnetic sensor. Therefore, a force sensor having a constant output according to sensitivity and force can be obtained at any position in the magnetic circuit formed by the yoke.

[Application Example 3]
The force sensor, wherein the magnetic field generator includes a permanent magnet.
In this application example, since a permanent magnet that does not require wiring is used for the magnetic field generator, a force sensor with a simple structure and a reduced manufacturing cost can be obtained.

Schematic of the force sensor in the first embodiment. (A) is a schematic plan view of a force sensor, (b) is an AA schematic sectional drawing in (a). (A) is a schematic expanded sectional view near the magnetic field generation part of a force sensor and a magnetic sensor, (b) is a related figure of the output voltage of a magnetic sensor, and the distance from a magnetic field generation part. The circuit diagram in case a magnetic sensor is a Hall element. In the modified example, (a) is a schematic enlarged cross-sectional view in the vicinity of the magnetic field generation unit and the magnetic sensor of the force sensor, and (b) is a relationship diagram between the output voltage of the magnetic sensor and the distance from the magnetic field generation unit. The figure which showed the compression characteristic of the elastic member. The schematic diagram of the force sensor in a 2nd embodiment. (A) is a schematic plan view, (b) is a schematic cross-sectional view taken along the line A-B-C-D-F in (a). The figure which showed the relationship between the center of an axial part, and the contact position of an object. The schematic diagram of the force sensor in a 3rd embodiment. (A) is a schematic plan view, (b) is a BB schematic sectional drawing in (a).

Hereinafter, embodiments will be described in detail with reference to the drawings.
(First Embodiment)
FIG. 1 shows a schematic diagram of a force sensor 10 in the present embodiment. (A) is a schematic top view of the force sensor 10, (b) is an AA schematic sectional drawing in (a).

In FIG. 1, the force sensor 10 includes a shaft 1 as a first base, an elastic member 2, a housing 3 as a second base, four magnetic field generators 4, four magnetic sensors 5, and a magnetic sensor 5. Position adjusting means 50 is provided.
A ring-shaped convex portion 11 is formed in the middle of the shaft portion 1. The housing 3 has a ring shape, and a groove 31 is formed on the inner surface thereof. The convex portion 11 of the shaft portion 1 is fitted into the groove 31 of the housing 3 via the elastic member 2. Therefore, the elastic member 2 is interposed between the shaft portion 1 and the housing 3.
In the figure, the axial direction of the shaft portion 1 is shown as the Z axis, and the direction in which the force is detected is shown as the X axis direction and the Y axis direction.

In addition, thrust bearings 6A and 6B are disposed in the Z-axis direction between the convex portion 11 and the groove 31, and the shaft portion 1 is not deformed so that the shaft portion 1 moves in the Z-axis direction or the shaft portion 1 is twisted. It has become difficult.
Therefore, the force sensor 10 in this embodiment is a force sensor that does not detect a moment of force.

  On the outer periphery 111 of the projection 11 of the shaft 1, two recesses 12 are formed in the X-axis direction and two in the Y-axis direction with the center 1 C of the shaft 1 interposed therebetween. A magnetic field generator 4 is provided. Further, a recess 32 is formed at the position of the groove 31 of the housing 3 facing the magnetic field generation unit 4, and the magnetic sensor 5 is disposed on the bottom surface 321 of the recess 32.

The shaft portion 1 and the housing 3 are less deformable than the elastic member 2 and are made of a nonmagnetic material. For example, as the metal, aluminum, nonmagnetic stainless steel, brass, zinc, magnesium, and other ceramics and hard resins can be used.
Examples of the elastic member 2 include silicon rubber, fluorine-based rubber, isoprene rubber, nitrile rubber, butyl rubber, chloroprene rubber, acrylic rubber, urethane rubber, ethylene propylene rubber, butadiene rubber, styrene butadiene rubber, natural rubber, and the like. It is possible to appropriately select the one that can take a larger deformation amount according to the required load and deformation amount.
An electromagnet, a permanent magnet, or the like can be used for the magnetic field generating unit 4. However, a permanent magnet is preferable because wiring is not required, the structure is simple, and the size can be reduced.
Suitable permanent magnets include ferrite magnets, NdFeB magnets, SmFe magnets, and alnico magnets. The number of permanent magnets may be one or two.
As the magnetic sensor 5, a Hall element, a magnetoresistive element semiconductor type, a flux gate type, or the like can be used.

In the force sensor 10, when the shaft portion 1 receives a force in the X-axis direction or the Y-axis direction, the shaft portion 1 acts so as to deform the elastic member 2, and an output corresponding to the deformation amount is generated. It has become.
For example, as indicated by the white arrow shown in FIG. 1B, when a force Fx is applied in the + X-axis direction of the shaft portion 1, a force is also applied to the elastic member 2 in the + X-axis direction. The member 2 is deformed, and the shaft portion 1 approaches the magnetic sensor 5 in the + X direction. When the magnetic field generator 4 moves with the movement of the shaft 1, the magnetic field surrounding the magnetic sensor 5 also changes, and the output voltages of the four magnetic sensors 5 change.

Here, the magnetic sensor 5 in the + X axis direction is the magnetic sensor (+ X), the magnetic sensor 5 in the −X axis direction is the magnetic sensor (−X), the magnetic sensor 5 in the + Y axis direction is the magnetic sensor (+ Y), The magnetic sensor 5 in the −Y-axis direction is defined as a magnetic sensor (−Y).
For example, assuming that the output voltage before the force Fx is applied in the + X-axis direction is V ₀ , the output voltages V _{+ X} , V _-X , V _{+ Y} , V of the magnetic sensor 5 after the force Fx is applied in the + X-axis direction. _-Y changes as follows:
Magnetic sensor (+ X) output voltage V _{+ X} > V ₀
Magnetic sensor (−X) output voltage V _−X <V ₀
Magnetic sensor (+ Y) output voltage V _{+ Y} = V ₀
Magnetic sensor (−Y) output voltage V _−Y = V ₀
From the comparison of these output voltages, it is determined that the force sensor 10 has applied the force Fx in the + X-axis direction. The magnitude of the force Fx can be determined by measuring the magnitude of the output voltage V in advance according to the magnitude of the force, and knowing the output voltage V.

The same applies to the force Fy in the + Y-axis direction, and changes as follows.
Magnetic sensor (+ X) output voltage V _{+ X} = V ₀
Magnetic sensor (−X) output voltage V _−X = V ₀
Magnetic sensor (+ Y) output voltage V _{+ Y} > V ₀
Magnetic sensor (−Y) output voltage V _−Y <V ₀
An oblique force can also be calculated from the composition of the output voltages in the X-axis direction and the Y-axis direction.

FIG. 2A is a schematic enlarged cross-sectional view of the vicinity of the magnetic field generator 4 and the magnetic sensor 5 of the force sensor 10.
FIG. 2B shows a relationship diagram between the output voltage of the magnetic sensor 5 and the relative movement distance with respect to the magnetic field generation unit 4 when the initial position L ₀ of the magnetic sensor 5 is set. Here, the direction toward the magnetic field generator 4 is represented as a positive direction. Hereinafter, the detection principle will be described with reference to the drawings.
In FIG. 2A, the magnetic field generating unit 4 and the magnetic sensor 5 are disposed to face each other with the elastic member 2 interposed therebetween. The magnetic field generation unit 4 includes two permanent magnets 41 and 42 and a yoke 43, and a magnetic circuit 45 is formed so that the magnetic flux 44 flows so as to spread toward the outer peripheral side of the convex portion 11 of the shaft portion 1 and returns again. Has been.

This magnetic flux 44 is detected by the magnetic sensor 5 and output as a voltage.
When the shaft 1 receives a force toward the magnetic sensor 5, the elastic member 2 is deformed, the distance between the magnetic field generator 4 and the magnetic sensor 5 is reduced, and the output of the magnetic sensor 5 is increased by increasing the magnetic flux 44. Become. As a result, force can be detected as voltage.
In FIG. 2B, when the relative movement distance from the initial position L ₀ of the magnetic sensor 5 to the magnetic field generation unit 4 increases (the distance between the magnetic field generation unit 4 and the magnetic sensor 5 decreases), The output voltage increases.

FIG. 3 shows a circuit example when the magnetic sensor 5 is a Hall element as a circuit diagram. OPAmp represents an operation amplifier, Tr represents a transistor, and R represents a resistance.
The circuit includes a constant current unit, an instrumentation amplifier unit, and a balance adjustment unit. As these circuits, well-known circuits can be used, and the circuit is not limited to the circuits shown in the drawings.

The Hall element measures the strength of the magnetic field, which is the density of the magnetic flux 44, according to the following principle.
In a p-type or n-type semiconductor sample, for example, a current is passed in the x direction and a magnetic field is applied in the y direction. At this time, charged particles (carriers) flowing through the semiconductor sample move in the z direction under the Lorentz force by the magnetic field. As a result, an electric field (Hall electric field) appears in a direction orthogonal to both the current and the magnetic field. This is the Hall effect, and the Hall element can measure the strength of the magnetic field using the Hall effect.
Examples of semiconductors used for the Hall element include gallium arsenide (GaAs), indium arsenide (InAs), and indium antimony (InSb). Indium antimony is highly sensitive but easily affected by temperature. Arsenic has characteristics such as being hardly affected by temperature, and can be used properly depending on the application.

In order to measure the magnetic field with high accuracy, it is better that the Hall current is constant, and the Hall current is made constant by the constant current portion. The Hall current can be determined by the resistance Rh.
A Hall voltage is generated at the output section of the Hall element, but since the voltage is small, it is amplified by the instrumentation amplifier section. The instrumentation amplifier unit has a single-ended output with a pair of differential input terminals and a reference terminal as a potential reference, high input impedance, and a common mode rejection ratio (CMR: COMMON MODE REJECTION) of 70 dB to 100 dB. Excellent to some extent.
The output voltage Vout of the instrumentation amplifier unit is expressed as shown in Expression (1) by the Hall voltage Vh and the gain of the instrumentation amplifier unit.

As described above, the Hall voltage Vh proportional to the magnetic field is obtained as the output. Further, when the zero point of the Hall voltage Vh amplified by the instrumentation amplifier unit is shifted, it can be adjusted by the balance adjusting unit.
By appropriately designing the material, dimensions, and shape of the permanent magnets 41 and 42, the gradient of the magnetic field gradient, which is a magnetic circuit in the space between the two permanent magnets 41 and 42, can be adjusted.
Further, the position of the magnetic sensor 5 can be moved with respect to the distribution of the magnetic flux 44 by the position adjusting means 50 of the magnetic sensor 5. As the position adjusting means 50, for example, the position of the magnetic sensor 5 can be mechanically adjusted in the X, Y, and Z axis directions using a screw, a micrometer, or the like.

(Modification)
FIG. 4A shows a schematic enlarged cross-sectional view in the vicinity of the magnetic field generator 40 and the magnetic sensor 5 in the modification. FIG. 4B shows a relationship diagram between the output voltage of the magnetic sensor 5 and the relative movement distance with respect to the magnetic field generator 40 when the magnetic sensor 5 is set to the initial position L ₀ , as in the first embodiment. The same components as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment.

The magnetic field generator 40 includes a permanent magnet 49 and two yokes 46 and 47, and a magnetic circuit 48 is configured so that the magnetic flux 44 flows so as to spread toward the outer peripheral side of the shaft 1 and returns again.
In this case, the magnetic field gradient in the space between the two 46 and 47 can be designed to be relatively uniform, and the gradient of the magnetic field gradient can be adjusted depending on the shape of the yokes 46 and 47. For example, the inclination of the magnetic field gradient can be changed by tapering the yokes 46 and 47 so that the yokes 46 and 47 are thinned away from the permanent magnet and changing the shape of the taper.

In FIG. 4A, the magnetic sensor 5 is disposed in a substantially uniform magnetic field gradient in the space between the yokes 46 and 47.
Further, depending on the shape of the yokes 46 and 47, it is possible to change the shape of the elastic member 2 so that the yokes 46 and 47 do not contact the elastic member 2. In the modified example, the elastic member 2 is not disposed in a portion of the yokes 46 and 47 that protrudes from the convex portion 11 of the shaft portion 1.

  The yokes 46 and 47 are provided with permeance adjusting means 60 so that the gradient of the magnetic field gradient and the like can be adjusted. Similar to the position adjusting means 50, the permeance adjusting means 60 can mechanically adjust the positions of the yokes 46 and 47 in the X, Y, and Z axis directions using, for example, a screw, a micrometer, or the like.

When the magnetic field gradient in the space between the yokes 46 and 47 is uniform, as shown in FIG. 4B, the magnetic field generator 40 when the output voltage of the magnetic sensor 5 and the initial position L ₀ of the magnetic sensor 5 are set. The relative movement distance with respect to is proportional.

  In the first embodiment and the modification, as the yokes 43, 46, 47, iron-based materials having high saturation magnetic flux density, electromagnetic soft iron, low carbon steel, silicon steel plate, etc. are suitable. Rust plating or painting is applied. The shapes of the yokes 43, 46 and 47 are preferably such that the magnetic resistance is reduced so that the magnetic flux from the permanent magnet passes through the magnetic sensor 5 as much as possible. A suitable shape can be selected from the permeance of the permanent magnet, and the shapes of the yokes 43, 46, and 47 can be designed accordingly.

In FIG. 5, the example of the compression characteristic of the elastic member 2 was shown. The horizontal axis indicates the load, and the vertical axis indicates the amount of displacement.
In FIG. 5, the amount of displacement is not proportional to the load and becomes a gently upward convex curve, but the shape of this curve also changes depending on the type of elastic member 2 selected and the manner of foaming.
The output characteristics (load-output voltage) of the force sensor 10 are both the compression characteristics (load-displacement amount) of the elastic member 2 and the output characteristics of the magnetic sensor 5 shown in FIGS. 2 (b) and 4 (b). It depends on.
In order to select the type of the elastic member 2, the elastic member 2 is selected from a comprehensive point of view such as compression characteristics, stability against repeated loads, temperature characteristics, etc. In particular, compression characteristics are important as an end effector of a robot. . First, the compression characteristics of the elastic member 2 are determined, the type and grade of the elastic member 2 are determined, and then the magnetic field gradients of the magnetic field generators 4 and 40 are designed so that the output characteristics of the magnetic sensor 5 have a proportional relationship. .
If the output characteristics of the magnetic sensor 5 are proportional, the load can be easily obtained from the output voltage, and no means for converting in consideration of the compression characteristics of the elastic member 2 is required.

  Further, it is sufficient that at least one of the position adjusting means 50 of the magnetic sensor 5 or the permeance adjusting means 60 of the yokes 46 and 47 is provided, and the magnetic field gradient is also provided by the position adjusting means 50 or the permeance adjusting means 60 of the yokes 46 and 47. Can be adjusted.

According to such this embodiment and modification, there exist the following effects.
(1) Since at least one of the position adjusting means 50 of the magnetic sensor 5 or the permeance adjusting means 60 of the yokes 46 and 47 constituting the magnetic circuit 48 is provided, the magnetic circuits 45 and 48 and the magnetic sensor 5 Adjustment of the relative position or at least one of the magnetic circuits 45, 48 can be made possible. When the shaft portion 1 and the housing 3 are assembled via the elastic member 2, the relative positions of the shaft portion 1 and the housing 3 are shifted due to elastic deformation of the elastic member 2, etc. Even when the relative position with respect to the sensor 5 is shifted and assembled, the position of the magnetic sensor 5 in the magnetic circuits 45 and 48 or at least one of the magnetic circuits 48 can be adjusted. Therefore, it is possible to obtain the force sensor 10 with little variation in output according to sensitivity and applied force.

  (2) Since permanent magnets that do not require wiring are used for the magnetic field generators 4 and 40, the force sensor 10 having a simple structure and a small manufacturing cost can be obtained.

According to the modification, the following effects are obtained.
(3) The shapes of the yokes 46 and 47 are formed so that the magnetic circuit 48 has a proportional relationship between the output of the magnetic sensor 5 and the moving distance of the magnetic sensor 5. Accordingly, the force sensor 10 having a constant output according to sensitivity and force can be obtained at any position in the magnetic circuits 45 and 48 formed by the yokes 46 and 47.

(Second Embodiment)
FIG. 6A is a schematic plan view of the force sensor 20 in the present embodiment, and FIG. 6B is a schematic cross-sectional view taken along the line A-B-C-D-F in FIG.
In this embodiment, a large number of magnetic sensors 5 and magnetic field generators 4 are arranged, and the force sensor 20 is multi-axial. The same components are denoted by the same reference numerals, and only those necessary for explanation are labeled. Components not described have the same functions and structures as those of the first embodiment even if the sizes and shapes are different. Further, the position adjusting means 50 and the permeance adjusting means 60 of the magnetic sensor 5 are omitted.
In the present embodiment, twelve pairs of the magnetic sensor 5 and the magnetic field generator 4 are provided. Of these, eight are provided in the Z-axis direction.

The elastic member 21 is provided in a ring shape inside a pair of the eight magnetic sensors 5 and the magnetic field generator 4 provided in the Z-axis direction. Also, the thrust direction receivers 6A and 6B in the first embodiment are not provided. Therefore, in addition to the X-axis direction, the Y-axis direction, and the Z-axis direction, moments Mx, My, and Mz in the X, Y, and Z-axis directions can be measured.
As an example, the moment M is indicated by a hatched arrow in the figure. The moment M has an X component and a Y component.
Note that a through hole 14 is formed in the shaft portion 13 of the present embodiment.

FIG. 7 is a diagram showing the relationship between the center of the shaft portion 13 and the contact position of the object.
The origin 0 of the coordinate is the center 1C of the shaft portion 13, and N ′ (X1, Y1) is the contact position between the shaft portion 13 and the object. The combined moment M of the position N ′ of the object with the origin 0 as the center is expressed as M = (Mx ² + My ² ) ^(1/2) where Mx is the X component of the moment and My is the Y component of the moment.
If the distance from the origin 0 to the point N ′ is r, the moment M around the Z axis is expressed by the force F as M = F × r.
From the sign of the moments Mx and My, it can be seen in which region (one of the first to fourth quadrants on the XY plane) the point N ′ is. Further, from the ratio of the moments Mx and My, the angle θ is tan θ = My / Mx.
From the distance r, the coordinates X1 and Y1 of the point N ′ are X1 = r × cos θ and Y1 = r × sin θ, respectively.

According to this embodiment, there are the following effects.
(4) Not only the forces in the X-axis, Y-axis, and Z-axis directions but also the components Mx, My, and Mz of the moment M can be measured.

(Third embodiment)
FIG. 8A shows a schematic plan view of the force sensor 70 in the present embodiment, and FIG. 8B shows a schematic cross-sectional view taken along line BB in FIG. The same components are denoted by the same reference numerals, and only those necessary for explanation are labeled. Components not described have the same functions and structures as those of the first embodiment even if the sizes are different.
Also in this embodiment, the position adjusting means 50 and the permeance adjusting means 60 of the magnetic sensor 5 are omitted.

In FIG. 8, the force sensor 70 includes a shaft portion 71 as a first base and a base 73 as a second base.
A disc-shaped support plate 72 is provided at one end of the shaft portion 71. The base 73 has a cylindrical shape having a bottom 731 and includes a ring-shaped lid 74. The lid 74 has an opening 741 at the center. A circuit portion 75 is provided on the bottom portion 731 of the base 73, and a support portion 76 is provided thereon.
On the support plate 72, the magnetic field generators 4 </ b> A, 4 </ b> B, 4 </ b> C, 4 </ b> D are arranged so as to be rotationally symmetric with respect to the center 7 </ b> C of the shaft part 71. On the other hand, magnetic sensors 5A, 5B, 5C, 5D are arranged on the support portion 76 so as to face the magnetic field generating portions 4A, 4B, 4C, 4D.

  The support plate 72 of the shaft portion 71 is held by the elastic member 22 between the lid portion 74 and the support portion 76 so that the support plate 72 and the support portion 76 of the shaft portion 71 are parallel to each other. Therefore, the elastic member 22 is interposed between the shaft portion 71 and the base 73. The shaft portion 71 protrudes from the opening 741.

For example, when a force Fx in the + X direction indicated by a white arrow in the drawing is applied to the shaft portion 71, the shaft portion 71 is displaced in the + X direction with respect to the base 73. Then, the outputs of the four magnetic sensors 5A, 5B, 5C, and 5D deviate from the equilibrium point, and the output voltage changes.
Here, the direction of the magnetic field gradient of the four magnetic field generators 4A, 4B, 4C, and 4D is changed to change the sign of the output voltage so that the direction of the force can be seen on the XY plane. For example, the output voltage of each magnetic sensor is set as shown in Table 1.

  Here, with respect to the force in the first quadrant direction (+ X + Y), 5A is +, 5B is ˜0, 5C is −5, and 5D is ˜0, and the force in the second quadrant direction is (−X + Y). On the other hand, 5A is ˜0, 5B is -5, -5C is ˜0, and 5D is an output of +, and in contrast to the force in the third quadrant (+ X−Y), 5A is ˜0, 5B is + 5C Is 0 and 5D is an output of-, and 5A is -5B is 0, 5C is + 5D, and 5D is 0 output with respect to the force in the fourth quadrant (-XY).

According to this embodiment, there are the following effects.
(5) The direction and magnitude of the force applied on the XY plane can be known from the amount of change in the output voltage of the magnetic sensors 5A, 5B, 5C, 5D.

Various changes can be made in addition to the above-described embodiments and modifications.
The shape of the yokes 46 and 47 is not limited to the shape surrounded by the plane shown in the modified example, but may be a shape having a curved surface. For example, when designing the magnetic field gradient of the magnetic field generators 4 and 40 so that the output characteristics of the magnetic sensor 5 have a proportional relationship, the shape of the yokes 46 and 47 is changed to a curved surface according to the compression characteristics of the elastic member 2. It is good also as a shape with.

Further, the arrangement of the magnetic field generation unit and the magnetic sensor is not limited to being arranged at a symmetric position with respect to the origin, the X axis, the Y axis, and the Z axis, and may be arranged at an asymmetric position.
Further, the first base is not limited to the one having the cylindrical shaft portions 1, 13, 71. For example, a triangular prism or a quadrangular prism may be used.

  DESCRIPTION OF SYMBOLS 1,13,71,72 ... Shaft part and support plate as 1st base | substrate, 2, 21, 22 ... Elastic member, 3 ... Housing as 2nd base | substrate, 4, 4A, 4B, 4C, 4D, 40 ... Magnetic field generator, 5, 5A, 5B, 5C, 5D ... Magnetic sensor, 10, 20, 70 ... Force sensor, 41, 42, 49 ... Permanent magnet, 43, 46, 47 ... Yoke, 45, 48 ... Magnetic Circuit: 50: Position adjusting means, 60: Permeance adjusting means, 73: Base as second substrate.

Claims (3)

A first base body having a magnetic circuit formed by a magnetic field generation unit including a yoke;
A second substrate having a magnetic sensor across the magnetic circuit;
An elastic member interposed between the first base and the second base and elastically deformed by a load applied between the first base and the second base;
A force sensor comprising: at least one of a position adjusting unit of the magnetic sensor and a permeance adjusting unit of the yoke. The force sensor according to claim 1,
The shape of the yoke is a shape that forms the magnetic circuit such that the output of the magnetic sensor and the moving distance of the magnetic sensor that moves in the magnetic circuit by the load are in a proportional relationship. Force sensor. The force sensor according to claim 1 or 2,
The magnetic field generation unit includes a permanent magnet.

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