JPH11148877A - Load sensor - Google Patents

Abstract

(57) [Problem] To provide an inexpensive load sensor used for an operation unit of a game machine, a pointing device of a personal computer, etc., which can set an operation load-output voltage level arbitrarily and easily. With the goal. SOLUTION: An elastic insulating resin substrate 1 having first and second pairs of strain detecting elements 5 and 6 disposed on a front surface thereof and an elastic metal reinforcing plate 2 are overlapped and fixed to a mount 4. With this configuration, the reinforcing plate 2 can be operated against a predetermined operation load of the operation shaft 3.
By appropriately selecting the material, shape, thickness and the like of the above, an arbitrary operation load-output voltage can be easily set, and a load sensor that can respond inexpensively can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is mainly used for an operation unit of a game machine, a pointing device of a personal computer, a remote controller of various electronic devices, and the like.
The present invention relates to a load sensor for performing a coordinate input (two-dimensional) on a display screen.

[0002]

2. Description of the Related Art As a conventional load sensor of this type, a load sensor described in Japanese Patent Application Laid-Open No. 7-174646 is known.

As shown in a perspective view of a conventional load sensor shown in FIG.
A rigid operating shaft 12 is provided at the center of the elastic plate 11 fixed to the mounting base 4 by A, and the elastic plate 11 is deformed by applying a force to the tip thereof. 12 and the fixing portion 4A of the mounting base 4, the fixing portion 4
A pair of first and second pairs of strain detecting elements 5 and 6 made of strain-sensitive resistors having the same resistance value are orthogonal to each other on a straight line connecting A and the operation axis 12 and at the same distance from the operation axis 12. They are provided in a positional relationship.

The operation of the load sensor having such a configuration is performed when a force is applied to the tip of the operation shaft 12 in a direction parallel to the elastic plate 11 as shown in a front sectional view illustrating the operation state of FIG. Of the first pair of strain detecting elements 5 of the elastic plate 11, the detecting element 5A is deformed into a concave surface and the detecting element 5B is deformed into a convex surface, and this deformation lowers the resistance value of the detecting element 5A and increases the resistance value of the detecting element 5B. Therefore, by calculating the difference between the resistance change of the detection elements 5A and 5B of the first pair of strain detection elements 5, the force applied in a state where the resistance change is doubled is detected. On the other hand, the detecting elements 6A and 6B of the second pair of strain detecting elements 6 do not generate a difference in resistance value change only when a torsional stress in the same direction is applied, and the first pair of strain detecting elements 6 Only the force in the coordinate axis direction of No. 5 can be detected.

Similarly, the distal end of the operating shaft 12 is moved in the direction A in parallel with the elastic plate 11 shown in FIG.
When a force is applied in the middle direction of A, the detection elements 5A and 6A
A is deformed into a concave surface, and 5B and 6B are deformed into a convex surface, and the deformation lowers the resistance values of the detection elements 5A and 6A.
Since the resistance value of B increases, the difference between the change in the resistance value of the detection elements 5A and 5B of the first pair of strain detection elements 5 and the change in the resistance value of the detection elements 6A and 6B of the second pair of strain detection elements 6 , And by comparing the differences, the magnitude and direction of the applied force can be detected and output.

As described above, the force applied to the operation shaft 12 can be separated in the directions of two coordinate axes, and its magnitude and direction can be detected and output.

[0007]

However, in the above-mentioned conventional load sensor, the material used for the elastic plate 11 is usually an expensive ceramic substrate or an enamel substrate, and the load sensor only uses the strength of the elastic plate 11. However, since the operating load-output voltage level is determined, there is a disadvantage that the degree of freedom of design is small and it is not possible to easily meet various user needs at low cost.

An object of the present invention is to solve such a conventional problem and to provide an inexpensive load sensor capable of arbitrarily and easily setting an operation load-output voltage level. It is.

[0009]

In order to solve the above-mentioned problems, a load sensor according to the present invention comprises a substrate made of an elastic insulating resin on which a strain detecting element is arranged and a reinforcing plate made of an elastic metal, which are overlapped with each other. And the periphery thereof is integrally fixed by a fixing portion of the mounting base.

According to the present invention, the operating load-output voltage can be easily set by changing the material, shape, thickness and the like of the reinforcing plate to be combined with one type of substrate, and a general-purpose insulating resin can be used. Since a material and an elastic metal material can be used in combination, an inexpensive load sensor can be realized.

[0011]

The invention according to claim 1 of the present invention has at least two strain detecting elements on the front surface,
A substrate made of an elastic insulating resin having a hole in the center thereof, a reinforcing plate made of an elastic metal disposed on the substrate and provided with a hole at a position corresponding to the hole of the substrate, and the substrate and the reinforcing plate Is a load sensor consisting of a mounting table that holds the fixed part and an operating shaft inserted and fixed in the holes of the substrate and the reinforcing plate. By selecting the material, shape, thickness, etc. of the reinforcing plate, It is possible to provide an inexpensive load sensor that can easily set an arbitrary operation load-output voltage and can also use a general-purpose insulating resin material and a metal material.

According to a second aspect of the present invention, in the first aspect of the present invention, the lower portion of the operating shaft comprises a small-diameter portion inserted into the hole of the substrate and the reinforcing plate, and a circular large-diameter portion above the lower portion. The stacked substrate and the reinforcing plate are sandwiched between the large-diameter portion lower surface and the seat plate fixed to the substrate and the lower surface of the reinforcing plate by the small-diameter portion, and the operating shaft and the seat plate firmly connect the substrate and the reinforcing plate. Since it can be fixed stably, there is an effect that it is possible to provide a load sensor having excellent responsiveness without play of the operation shaft during use.

According to a third aspect of the present invention, in the second aspect of the present invention, the lower end surface of the large diameter portion of the operating shaft or the end portion of the outer diameter of the seat plate is combined with the combination in which the reinforcing plate is overlapped on the back surface of the substrate. Is arranged above or below the substrate front surface so as to press the vicinity of the distortion detection element of the substrate front surface,
When a load is applied to the operation shaft, the largest distortion occurs at the large diameter portion lower end surface of the operation shaft holding the substrate and the reinforcing plate or at the abutting portion of the end of the seat plate outer diameter. This has the effect of increasing the amount of distortion of the arranged strain resistance element, and as a result, obtaining a large output voltage.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the shape of the reinforcing plate is:
It is connected to the outer peripheral frame at a connecting portion of a predetermined width centered on a straight line connecting the strain detecting element on the substrate front surface and the central operating axis, and the load applied to the operating shaft is connected to the reinforcing plate. Since it concentrates on the portion, the largest strain can always be generated in the strain resistance element on the substrate irrespective of the operation direction of the operation shaft, so that there is an effect that a stable operation load-output voltage characteristic can be obtained.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the substrate has flexibility and is attached to the reinforcing plate with an adhesive, and the substrate has a distortion. Since the lead-out portion of the electric signal from the resistance element to the outside can be formed integrally with the substrate, the number of components can be reduced, and a compact, highly reliable and inexpensive load sensor can be realized.

According to a sixth aspect of the present invention, in the fifth aspect, the main component of the adhesive is a thermosetting resin, and the adhesive made of the thermosetting resin has a three-dimensional network structure. Because it is developed, plastic deformation is small and it is hard to be affected by the use environment, so it is possible to reliably transmit the amount of distortion of the reinforcing plate to the strain detection element on the flexible board, and the hysteresis is small and responsiveness is small. This has the effect that a good load sensor can be provided.

According to a seventh aspect of the present invention, in the invention according to any one of the first to sixth aspects, the strain detecting element is a strain gauge. , It is possible to easily and flexibly cope with production.

According to an eighth aspect of the present invention, in the first aspect of the present invention, the strain detecting element comprises a strain sensitive resistor printed and formed on a substrate. By forming the strain detecting element directly on the substrate by a method such as thick-film printing, the displacement of the strain detecting element and the variation of the resistance value can be suppressed to be small, so that mass production can be performed with high accuracy and at low cost. This has the effect of providing a load sensor having an excellent strain detecting element.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. The same components as those described in the section of the related art are denoted by the same reference numerals, and detailed description will be omitted.

(Embodiment 1) FIG. 1 is an external perspective view of a load sensor according to a first embodiment of the present invention, FIG. 2 is an exploded perspective view thereof, and FIG. 3 is a front sectional view thereof. , 1
Is a substrate made of elastic insulating resin, 2 is a reinforcing plate made of elastic metal,
The small holes 1B and 2B are provided at the same positions at the four surrounding positions, and the small holes 1B and 2B are inserted into the fixing portions 4A protrudingly provided at the four positions around the mounting base 4 and fixed. 4A
The substrate 1 and the reinforcing plate 2 are fixed to the mounting table 4 in a state of being overlapped by caulking the upper end of the substrate 1.

Reference numeral 3 denotes a rigid operation shaft having an operation portion 3A at the upper end, a large-diameter portion 3B at the lower end, and a small-diameter portion 3C concentric with the operation portion. The small-diameter portion 3C is provided at the center of the substrate 1 and the reinforcing plate 2. Holes 1A and 2A, and a ring-shaped fitting that is inserted below the holes 1A and 2A, and is inserted through a central through-hole 7A of a seat plate 7 having the same outer diameter as the large-diameter portion 3B of the operation shaft 3, and the lower end is swaged. As a result, the substrate 1 and the reinforcing plate 2 are fixed while being sandwiched between the lower surface of the large diameter portion 3B of the operation shaft 3 and the seat plate 7.

An end of the lower surface of the large-diameter portion 3B is provided on the front surface of the substrate 1 on a straight line connecting the fixed portion 4A of the mounting base 4 and the operation shaft 3 and at the same distance from the operation shaft 3. In the vicinity of the position where the 3D abuts on the substrate 1, four strain-sensitive resistors having the same resistance value are printed and formed so as to be orthogonal to each other to form first and second two pairs of strain detecting elements 5 and 6. ing.

On the other hand, the reinforcing plate 2 superposed on the back surface of the substrate 1 has a flat plate-like connection formed at a predetermined width around a straight line connecting the fixing portion 4A of the mounting base 4 and the operation shaft 3 as a center line. The parts 2C are provided in a positional relationship orthogonal to each other, and are connected to the outer peripheral frame part 2D.

The operation of the load sensor configured as described above will be described with reference to the front sectional view of FIG. 4 which illustrates the operation state of the load sensor. When a load is applied to the substrate, the substrate 1 and the reinforcing plate 2
Is firmly held and fixed in a state of being sandwiched between the lower surface of the large diameter portion 3B of the operation shaft 3 and the seat plate 7, so that the operation shaft 3
The substrate 1 and the reinforcing plate 2 are both elastically deformed by the load applied to the substrate 1, and among the first pair of strain detecting elements 5 of the substrate 1, the detecting element 5A is deformed into a concave surface and the detecting element 5B is deformed into a convex surface. The resistance value decreases in the detection element 5A and increases in the detection element 5B, and the applied load is detected by calculating the difference in resistance value change between the detection elements 5A and 5B of the first pair of strain detection elements 5. The operation that can be performed is the same as that of the prior art, but the operation axis 3
The portion where the end 3D of the lower surface of the large diameter portion 3B abuts is the position where the amount of distortion of the substrate 1 is the largest and the load is concentrated on the joint 2C of the reinforcing plate 2, so that a large output voltage is responsive. Can get better.

On the other hand, since the second pair of strain detecting elements 6 only apply a torsional force in the same direction, there is no difference in resistance value change, and only the coordinate axis direction of the first pair of strain detecting elements 5 is used. Can be detected as in the case of the related art.

Further, the operation portion 3A of the operation shaft 3 is moved in the direction A in parallel with the substrate 1 shown in FIG. 1, that is, the detection elements 5A and 6A
When a load is applied in the middle direction of the above, the detecting elements 5A and 6A are deformed into concave surfaces, and the detecting elements 5B and 6B are deformed into convex surfaces. This deformation lowers the resistance values of the detecting elements 5A and 6A, By increasing the resistance value, the difference between the change in the resistance value of the detection elements 5A and 5B of the first pair of strain detection elements 5 and the difference between the change in the resistance value between the detection elements 6A and 6B of the second pair of strain detection elements 6 are determined. , Respectively, and by comparing the difference between the two, the magnitude and direction of the applied load can be detected in the same manner as in the prior art. However, the elastic insulating resin substrate 1 is made of an elastic metal reinforcement. Since the load is deformed with a much smaller load than the plate 2, the load is concentrated on the joint 2C of the reinforcing plate 2 in the same manner as when the load is applied in the direction a, and the load is also applied in the direction a. Largest for the strain resistance element on the substrate Joined by themselves, stable operation load -
Output voltage characteristics can be obtained.

Therefore, according to the present embodiment, the first and second two pairs of strain detecting elements 5 and 6 provide high sensitivity regardless of the direction in which the load is applied to the operation portion 3A of the operation shaft 3. It is possible to obtain a stable operation load-output voltage characteristic that can be detected.

In the present embodiment, the reinforcing plate 2 is formed such that the flat connecting portion 2C having a predetermined width is connected to the outer peripheral frame portion 2D. The end of 2C may be superimposed on the substrate 1 and fixed to the fixing portion 4A of the mounting base 4. Even if the outer peripheral frame 2D and the connecting portion 2C are formed as a single flat plate, two pairs of strain detecting elements are provided. Detection at 5 and 6 is possible.

The operation part 3A of the operation shaft 3 is connected to the large diameter part 3B.
The seat plate 7 may have the same diameter as the large diameter portion 3B of the operating shaft 3.
It goes without saying that smaller diameters may be used.

Further, it is needless to say that strain gauges may be used as the two pairs of strain detecting elements 5 and 6, and the board 1 and the reinforcing plate 2 are turned upside down and fixed to the mounting table 4 to be fixed. 7, two pairs of strain detecting elements 5 near the end.
Of course, the same effect can be obtained even if the configuration in which 6 are arranged is provided.

(Embodiment 2) FIG. 5 is an exploded perspective view of a load sensor according to a second embodiment of the present invention, FIG. 6 (a) is a front sectional view thereof, and FIG. FIG. 3 is a partially enlarged cross-sectional view of a c portion shown in (). The load sensor according to the present embodiment is different from the first embodiment in that the substrate is a flexible substrate 8.

That is, as shown in FIGS. 5 and 6A, the shape of the flexible substrate 8 is such that the hole 8A
It is provided with a wiring pattern 8D having small holes 8B at four peripheral places and a lead-out part 8C at the end for leading out an output signal to the outside, and a central hole 2A of the reinforcing plate 2.
And the hole 8A and the small hole 8 at the positions of the four small holes 2B around it.
Together with B, both are adhered by an adhesive 9 whose main component is a thermosetting resin (see FIG. 6B).

This adhesive can reduce the hysteresis due to the small plastic deformation due to the development of the three-dimensional network structure, and is hardly affected by the use environment such as temperature.

Then, the attached flexible substrate 8
And the reinforcing plate 2, the four small holes 8 B and 2 B at the periphery are fixed by the fixing portion 4 A of the mounting base 4, and the flexible substrate 8 and the holes 8 A and 2 A of the reinforcing plate 2 are connected to the large diameter of the operating shaft 3. Part 3B
It is the same as the configuration of the first embodiment that it is sandwiched and fixed while being sandwiched between the lower surface and the seat plate 7.

The operation shaft 3 on the upper surface of the flexible substrate 8
The first and second pairs of strain detecting elements 5 and 6 are arranged in the vicinity of the end 3D of the lower surface of the large diameter portion 3B in the same manner as in the first embodiment.

When a load is applied to the operating portion 3A of the operating shaft 3, the load sensor having the above-described configuration is configured to fix the flexible substrate 8 fixed by the adhesive 9 with the elastic deformation of the connecting portion 2C of the reinforcing plate 2. Is elastically deformed, and the distortion is transmitted to the first and second two pairs of strain detecting elements 5 and 6 on the flexible substrate 8, and the resistance value is changed. The magnitude and direction of the applied load can be detected in the same manner as in the first embodiment, but the first and second two pairs of strain detecting elements 5 on the upper surface of the flexible substrate 8 are also provided. , 6 can be formed integrally with the flexible substrate 8, so that the number of components can be reduced, and a compact, highly reliable and inexpensive load sensor can be realized.

In the present embodiment, the flexible substrate 8 has the small holes 8B at four locations around it for fixing to the mounting table 4. However, the flexible substrate 8 has four small holes 2B around the reinforcing plate 2. Only the fixing portion 4A of the mounting base 4 may be fixed, and the flexible substrate 8 may be fixed only to the reinforcing plate 2 with an adhesive 9.

Although the main component of the adhesive 9 is a thermosetting resin, the first and second pairs of strain detecting elements can be used even if an adhesive mainly containing a thermoplastic resin is used. It is needless to say that detection is possible.

[0039]

As described above, according to the present invention, the desired operating load-output voltage can be easily set by changing the material, shape, thickness, etc. of the reinforcing plate to be combined with one type of substrate. And a general-purpose insulating resin material and elastic metal material can be used in combination, so that an advantageous effect that an inexpensive load sensor can be provided is obtained.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a load sensor according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the same.

FIG. 3 is a front sectional view of the same.

FIG. 4 is a front sectional view illustrating the operation state.

FIG. 5 is an exploded perspective view of a load sensor according to a second embodiment of the present invention.

FIG. 6A is a front sectional view of the same. FIG.

FIG. 7 is an external perspective view of a conventional load sensor.

FIG. 8 is a front sectional view illustrating the operation state.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Board 1A, 2A, 8A Hole 1B, 2B, 8B Small hole 2 Reinforcement plate 2C Joint 2D Peripheral frame 3 Operation shaft 3A Operation part 3B Large diameter part 3C Small diameter part 3D End 4 Mounting base 4A Fixed part 5 First pair of strain detecting elements 5A, 5B, 6A, 6B Detecting element 6 Second pair of strain detecting elements 7 Seat plate 7A Through hole 8 Flexible board 8C Outgoing part 8D Wiring pattern 9 Adhesive

Claims (8)

[Claims] 1. A substrate made of an elastic insulating resin having at least two strain detecting elements on a front surface and having a hole at the center thereof, and a substrate which is disposed on the substrate and corresponds to the hole of the substrate. A load sensor comprising an elastic metal reinforcing plate having a hole at a position to be mounted, a mounting table for holding the substrate and the reinforcing plate at a fixed portion, and an operation shaft inserted and fixed through the hole of the substrate and the reinforcing plate. 2. The lower part of the operating shaft comprises a small-diameter portion inserted into the hole of the substrate and the reinforcing plate, and a circular large-diameter portion above the small-diameter portion. 2. The load sensor according to claim 1, wherein the load sensor is held by a seat plate fixed to the lower surface of the substrate and the reinforcing plate by the small diameter portion. 3. A lower end surface of a large diameter portion of the operation shaft or an end portion of an outer diameter of a seat plate presses the vicinity of a distortion detecting element on a front surface of the substrate, in a combination in which a reinforcing plate is superimposed on a back surface of the substrate. 3. The load sensor according to claim 2, wherein the front surface of the substrate is disposed above or below. 4. The reinforcing plate is connected to the outer peripheral frame at a connecting portion having a predetermined width centered on a straight line connecting the strain detecting element on the substrate front surface and the central operation axis. The load sensor according to claim 1. 5. The load sensor according to claim 1, wherein the substrate has flexibility and is attached to the reinforcing plate with an adhesive. 6. The load sensor according to claim 5, wherein the main component of the adhesive is a thermosetting resin. 7. The load sensor according to claim 1, wherein the strain detecting element is a strain gauge. 8. The strain detecting element according to claim 1, wherein the strain detecting element is constituted by a strain sensitive resistor printed on a substrate.
7. The load sensor according to any one of 6.