JP2002055004A - Force detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost and thin type force detector. SOLUTION: The force detector can measure the magnitude and direction or distribution of a force having worked on an operation part 2, by putting variable resistors with a specific angle interval between a substrate 1 and the operation part 2 and detecting the variations of the resistance values of the variable resistors. Each variable resistor is constituted of a pair of conduction lands, provided to one of the substrate 1 and the operation part 2 and a constant resistance generation plate consisting of rubber or elastomer provided on the other side. On the opposite face of the pair of conduction lands in the contact resistance generation plate, a multitude of small projections (t) are formed, so that when a force is added to the operation part 2 to contact resistance generation plate to the pair of conduction land, the small projections (t) are crushed according to the magnitude of the force and the contact area between the contact resistance generation plate and the pair of conduction lands becomes large and accordingly, the resistance between the pair of conduction lands becomes small.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a force detecting device.

[0002]

2. Description of the Related Art As a force detecting device, for example, as shown in FIG. 14, strain gauges 91 are attached to four side surfaces of a quadrangular prism which is an operation shaft 90, and at the same time, a force in an XY axis direction is detected. Constituting a bridge circuit including the strain gauge 91,
Some devices detect the magnitude and direction of a force acting in the X-Y axis directions.

However, in this force detecting device, FIG.
As shown in (1), there is a problem that the thickness is difficult due to the presence of the operation shaft 90, and the cost is high.

[0004] Therefore, the industry dealing with this type of force detection device has been waiting for the development of an inexpensive and thin force detection device.

[0005]

Accordingly, an object of the present invention is to provide an inexpensive and thin force detecting device.

[0006]

Means for Solving the Problems (Invention of Claim 1)
The force detection device according to the present invention has a variable resistor interposed between the substrate and the operation unit at a predetermined angular interval, and detects a change in the resistance value of each variable resistor, thereby detecting the force acting on the operation unit. A force detection device capable of measuring the size and direction, or the distribution of force, wherein each variable resistor includes a pair of conductive lands provided on one of a substrate and an operation unit, and a conductive rubber provided on the other. Or a contact resistance generating plate made of an elastomer, and a large number of minute projections are formed on a surface of the contact resistance generating plate facing the pair of conductive lands, and the contact resistance generating plate and the pair of conductive lands are formed. When a force is applied to the operation unit to make contact with the conductive land, the minute protrusion is crushed in accordance with the force, and the contact area between the contact resistance generating plate and the pair of conductive lands increases, and accordingly, A pair of conductive runs Resistance between the are to be smaller. (Invention of claim 2) The force detecting device of the present invention is configured such that variable resistors are interposed at a predetermined angle interval between the substrate and the operation unit, and a change in the resistance value of each variable resistor is detected. A force detection device capable of measuring the magnitude and direction of the force applied to the operation unit, or the distribution of the force, wherein each variable resistor includes a pair of conductive lands provided on one of the substrate and the operation unit, and the other And a non-conductive rubber or non-conductive elastomer contact resistance generating plate having a large number of minute projections to which conductive ink or conductive paint is attached. When a force is applied to the operating portion to make contact with the pair of conductive lands, the small projections are crushed in accordance with the force, and the contact area between the contact resistance generating plate and the pair of conductive lands increases, and A pair of conductive runs Resistance between the are to be smaller. (The invention according to claim 3) The force detecting device according to the present invention relates to the invention according to claim 1 or 2, wherein the variable resistor has 180
It is provided between the substrate and the operation unit at an interval of °. (Invention of claim 4) A force detecting device according to the present invention relates to the invention of claim 1 or 2, wherein the variable resistor is 90 °.
X-Y is provided between the substrate and the operation unit at an interval, and acts on the operation unit by a change in the resistance value of the variable resistor.
The magnitude and direction of the axial force or the distribution of the force can be measured. (A fifth aspect of the present invention) A force detecting device according to the first aspect of the present invention relates to the first aspect of the present invention, wherein a force is applied to the pair of conductive lands when no force is applied to the operating portion. The resistance generating plate is separated, and the resistance between the pair of conductive lands is infinite. According to a sixth aspect of the present invention, there is provided a force detecting device according to any one of the first to fifth aspects, wherein two concentric circular conductive members are formed on a substrate at a center between the variable resistors. A land is provided as a switch terminal.On the other hand, a switch plate serving as a switch contact having a conductive rubber surface, a conductive elastomer surface, a conductive ink surface or a conductive paint surface is fixed to a button portion of the operation unit, and a contact resistance generating plate is provided. When a force is applied to the button to bring the pair of conductive lands into contact with each other,
The switch plate comes into contact with the two concentric conductive lands, and the space between the two conductive lands is closed. According to a seventh aspect of the present invention, there is provided a force detecting device according to the sixth aspect, wherein a distance between a contact resistance generating plate constituting a variable resistor and a pair of conductive lands, a concentric circle with a switch plate. The distance between the two conductive lands,
The contact timing between the contact resistance generating plate and the pair of conductive lands and the contact timing between the switch plate and the two concentric conductive lands are shifted. (Invention of Claim 8) The force detecting device of the present invention relates to the invention of any one of the above-mentioned claims 1 to 7, and can transmit a click feeling to a hand when operated.

The function of the force detecting device of the present invention will be clarified in the following embodiments of the present invention.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the drawings showing embodiments. [Embodiment 1] FIG. 1 is a sectional view of a force detecting device S of the present invention. FIG. 2 is a sectional view of a conductive land DX1, DX2, DX3, DX4, DY1, DY on a substrate 1 constituting the force detecting device S. DY
2, DY3, DY4 and conductive lands DS1, DS2. FIG. 3 shows a contact resistance generating plate DGX1, provided on the lower surface of the button unit 20 of the operation unit 2 constituting the force detecting device S.
DGX3, DGY1, DGY3 and the switch plate 23 are shown.

As shown in FIG. 1, the force sensor S comprises a substrate 1, an operation unit 2 disposed opposite to the substrate 1, and a fixing unit 3 for fixing the operation unit 2 on the substrate 1. Have been.

The substrate 1 is formed of a thin printed board as shown in FIG. 1, and has four circular conductive lands DX1, DX2 / DX3, DX4 / D on its upper surface as shown in FIG.
Y1, DY2 / DY3, DY4 are arranged on the XY axis at an equal distance from the origin O, and conductive lands DS1, DS2 are arranged around the origin O.

Here, as shown in FIG.
S2 is a ring-shaped conductive land DS1 formed inside the ring.
Are formed in a circular shape, respectively, and as shown in FIG. 1, are drawn out at appropriate positions as terminals TS1 and TS2.

The conductive lands DX1, DX2 / DX3, DX4
As shown in FIG. 1, / DY1, DY2 / DY3, and DY4 are terminals TX1, TX2 / TX3, TX4 / TY1, T
Y2 / TY3, TY4 are derived as.

As shown in FIGS. 1 and 3, the operating portion 2 is made of rubber or elastomer formed in a cup shape, and is formed of the conductive lands DX1, DX2 / DX3, DX4 / DY1, D
A button portion 20 having a circular shape in plan view disposed at a portion facing Y2 / DY3, DY4 and conductive lands DS1, DS2; and the conductive lands DX1, DX2 / DX3, DX4 / DY1, DY2 / DY3, D
An annular mounting portion 21 mounted on the substrate 1 so as to surround Y4, a thin deformed portion 22 connecting the outer peripheral surface of the button portion 20 and the upper end surface of the mounting portion 21 all around, and a conductive rubber. And the conductive lands DX1, DX2 / DX of the button portion 20
3, contact resistance generating plates DGX1, DGX3, DGY1, DGY3 fixed to the surfaces facing DX4 / DY1, DY2 / DY3, DY4
And a switch plate 23 made of conductive rubber and fixed to the surface of the button portion 20 facing the conductive lands DS1 and DS2.

Here, the contact resistance generating plates DGX1, DGX
Conductive lands DX1, DX2 / D on X3, DGY1, DGY3
The surfaces facing X3, DX4 / DY1, DY2 / DY3 and DY4 are shown in FIG.
As shown in FIG. 7, a large number of minute projections t are formed, and when a force or pressure is applied to push the button portion 20, the minute projections t are crushed and the contact resistance generating plates DGX1, DGX3, D
GY1, DGY3 lower surface and conductive lands DX1, DX2 / DX3, D
The contact area with X4 / DY1, DY2 / DY3, DY4 is changed.

Further, the surface of the switch 23 facing the conductive lands DS1 and DS2 is flat as shown in FIG.

As shown in FIG. 1, the fixing portion 3 has an inverted L section.
It is an annular shape formed in the shape of a letter.
The upper surface is pressed down.

Next, functions and the like of the force detecting device S of this embodiment will be described. (1) When the button portion 20 is pressed with a finger, the deformed portion 22 buckles and a light click feeling is transmitted to the finger.
Approach the upper conductive land. Now, as shown in FIG. 4, when a button portion 20 is pressed so as to press the contact resistance generating plate DGX1 against the substrate 1 by applying a force in the X-axis direction, the contact resistance generating plate DGX1 And comes into contact with the conductive lands DX1 and DX2 on the substrate 1. Contact resistance generating plate D
Since GX1 has a small protrusion t on its lower surface, the contact area between the contact resistance generating plate DGX1 and the conductive lands DX1, DX2 changes according to the magnitude of the pressing force of the button portion 20. Therefore, the contact resistances RX1 and RX2 between the contact resistance generating plate DGX1 and the conductive lands DX1 and DX2 also change according to the magnitude of the pressing force of the button portion 20, but when the surface of the contact resistance generating plate is flat. In comparison with the force, the rate of change according to the magnitude of the force is small, and when operated with a finger or the like, an effect is obtained that the operation is easy. At this time, the other contact resistance generating plates DGX3, DGY1 and DGY3 also have the conductive lands DX3 and DG3 on the opposing substrate 1 depending on the magnitude of the force applied to the button portion 20.
DX4 / DY1, DY2 / DY3, DY4
The contact resistance is larger than the contact resistances RX1 and RX2.

If the inherent resistance of the contact resistance generating plate DGX1 is Rdgx1, the combined resistance between the terminals TX1 and TX2 is RX
12 is RX12 = RX1 + Rdgx1 + RX2. However, when the button section 20 is not pressed, the contact resistance generating plate DGX1 is not in contact with the conductive lands DX1, DX2, so that RX12 is infinite. (2) The same can be said for the pressing force of the button portion 20 in the Y-axis direction because of the symmetry. Therefore, other terminals TX3,
A combined resistance RX34 between TX4, a combined resistance RY12 between terminals TY1 and TY2, and a combined resistance RY between terminals TY3 and TY4.
Numeral 34 changes from infinity according to the direction and magnitude of the force pressing the button unit 20. (3) Next, as shown in FIG. 5, when the button 20 is pressed uniformly with respect to the XY axes, the combined resistances RX12, R
X34, RY12 and RY34 change almost equally. (4) The above (1) to (3) are summarized in Table 1.

[0019]

[Table 1]

(5) When the button portion 20 is pressed uniformly with respect to the XY axes, the switch plate 23 is connected to the conductive lands DS1,
Touch DS2. Since the surface of the switch plate 23 is flat, the contact resistance between the switch plate 23 and the conductive lands DS1 and DS2 is small, and the terminals TS1 and TS2 are electrically closed to perform the same function as a switch. . When the button portion 20 is pressed unevenly with respect to the XY axis, the magnitude of the pressed force and the contact resistance generating plates DGX1, DGX
3, because it depends on the deformation of the DGY1, DGY3 and the switch plate 23, it is difficult to determine whether the terminals TS1, TS2 are open or closed. (6) The above can be expressed as a circuit as shown in FIG. FIG. 7 shows an application circuit according to the embodiment of the present invention (in FIG. 7, reference symbol r is a fixed resistor). In the circuit of FIG.
X3, VY1, VY3 are measured, and (VX1-VX3) and (VY1-
By calculating (VY3) by an appropriate method, the force in the XY axis direction can be detected, and by calculating (VX1 + VX3 + VY1 + VY3), the force in the Z-axis direction can be detected. Further, for example, when applied to a joystick, when no operation is performed, the combined resistances RX12, RX34, RY12, and RY34 are infinite, so that no current flows and power saving is excellent. (7) FIG. 8 shows the following application circuit (in the figure, symbol r is a fixed resistor)
It is. VX and VY are XY applied to the button unit 20.
Indicates the magnitude and direction of the axial force. (8) The conductive lands DX1 and DX2 on the substrate 1 are shown in FIG.
As shown in FIG. (9) The contact resistance generating plates DGX1, DGX3, D of the above embodiment
The GY1, DGY3 and the switch plate 23 are made of a conductive rubber, but are not limited thereto, and may be made of a conductive elastomer. You may comprise by printing a hydrophilic paint. The combined resistors RX12 and RX between the terminals in FIG.
34, RY12 and RY34 can be adjusted by changing the resistivity, material, hardness and surface form of the conductive rubber or conductive elastomer of the contact resistance generating plate. (10) Conductive lands DX1, DX2 / DX3, DX4 / D on substrate 1
Y1, DY2 / DY3, DY4 and conductive lands DS1, DS2 may be arranged as necessary. For example, conductive lands DX1,
If only DX2 / DX3 and DX4 are arranged, the magnitude can be detected only in the direction of the force in the X direction. When it is desired to detect the directions of the forces in eight directions, the lines of the respective detection directions 1, 2, 3, 4, 5, 6, 7, and 8 are sandwiched on the substrate 1 as shown in FIG. Conductive land D11, D12 / D21, D22
.. / D81 and D82 are arranged. On the other hand, as shown in FIG.
On lines 2,3,4,5,6,7,8 and D11,
DG1, DG2,... DG8 corresponding to D12 / D21, D22 /... / D81, D82 may be arranged. (11) In the force detecting device S shown in FIG. 1, the switch plate 23 of the button unit 20 and the contact resistance generating plates DGX1, DGX3, DG
Using the height of Y1, DGY3 and the elastic deformation of rubber, the switch is closed and the contact resistance generating plates DGX1, DGX3, DGY1, DGY3 and the conductive lands DX1, DX2 / DX3, DX4 / DY1, DY2 / DY3, DY4
The timing at which the combined resistance changes between them can be relatively changed. For example, as shown in FIG.
If the button 23 is made to protrude slightly (indicated by the symbol Δh) from the conductive land DX1 or the like, when the button 20 is pressed uniformly in the XY directions, the switch is closed first and the button 20 is further pressed.
, The combined resistances RX12, RX34, RY12, RY34 according to the magnitude and direction of the force pressing the button section 20.
Changes. Conversely, if the conductive lands DX1 and the like are slightly protruded from the switch plate 23, the combined resistances RX12, RX34, RY12, and RY34 change first, and then the switches are closed. (12) In the force detection device S shown in FIG. 1, as shown in FIG. 13, the operation part 2 and the switch plate 23 are integrally formed of rubber (or elastomer) having high hardness, and the contact surface of the switch plate 23 is formed. The contact resistance generating plates DGX1, DGX3, DGY1, and DGY3 are made of low-hardness rubber (or elastomer).
Is set smaller than the size indicated by reference symbol b. The force detection device S shown in FIG. 13 functions as follows. Since the switch plate 23 is hard and does not deform so much even when the button portion 20 is pressed, the terminal TS1 and TS2 must be pressed unless the button portion 20 is pressed so that the surface of the conductive ink IC completely contacts the conductive lands DS1 and DS2. Does not close. Here, in a state where the button portion 20 is pushed in so that the surface of the conductive ink IC completely contacts the conductive lands DS1 and DS2 to close the terminals TS1 and TS2, the relation of dimension a <dimension b is obtained. Since the contact resistance generating plates DGX1, DGX3, DGY1, DGY3 are not in contact with the conductive lands DX1, DX2 / DX3, DX4 / DY1, DY2 / DY3, DY4, the combined resistances RX12, RX34, RY12,
RY34 is infinite. The combined resistors RX12, RX34,
To change the resistance values of RY12 and RY34, the button 20 may be tilted and pushed. In this case, since the surface of the conductive ink IC does not contact both of the conductive lands DS1 and DS2, the terminal TS1 and TS2 are not closed. That is, the force detection device S shown in FIG.
2, RX34, RY12, and RY34 do not change simultaneously. The force detection device S having such a function is very useful depending on the application. In addition, if the force detection device S of the embodiment of the present invention is used, the distribution of force can be measured. The force detecting device S according to the embodiment of the present invention is thin because it does not require an operation shaft, and is inexpensive because it does not use expensive strain gauges that are difficult to attach.

[0021]

The present invention has the following effects since it has the above-described configuration. As is clear from the description of the embodiments of the present invention, an inexpensive and thin force detecting device can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a force detection device according to an embodiment of the present invention.

FIG. 2 is a plan view of a conductive land formed on a substrate constituting the force detection device.

FIG. 3 is a plan view of a contact resistance generating plate and a switch plate formed on a button part constituting the force detecting device.

FIG. 4 is a sectional view when a force is applied to a button portion of the force detection device.

FIG. 5 is a cross-sectional view when a force is applied to a button portion of the force detection device.

FIG. 6 is a diagram illustrating a variable resistor and a terminal in an electric circuit.

FIG. 7 is a diagram of an application circuit that can be employed in this embodiment.

FIG. 8 is a diagram of another application circuit that can be adopted in this embodiment.

FIG. 9 is a plan view of conductive lands and terminals on a substrate constituting the force detection device.

FIG. 10 is a plan view of conductive lands on a substrate used when detecting forces in eight directions.

FIG. 11 is a plan view of a contact resistance generating plate and a switch plate of a button portion used when detecting forces in eight directions.

FIG. 12 is a cross-sectional view of a force detection device according to another embodiment.

FIG. 13 is a cross-sectional view of a force detection device according to another embodiment.

FIG. 14 is an external perspective view of a prior art force detection device.

[Explanation of symbols] D conductive land t minute protrusion 1 substrate 2 operation part 3 fixing part 23 switch plate TX1 terminal TX1 terminal TX2 terminal TX3 terminal TX4 terminal TY1 terminal TY2 terminal TY3 terminal TY4 terminal TS1 terminal TS2 terminal DGX1 Contact resistance generation plate D Contact resistance generator plate DGY1 Contact resistance generator plate DGY3 Contact resistance generator plate DX1 Conductive land DX2 Conductive land DX3 Conductive land DX4 Conductive land DY1 Conductive land DY2 Conductive land DY3 Conductive land DY4 Conductive land DS1 Conductive land DS2 Conductive land

Claims (8)

[Claims] 1. A magnitude and direction of a force applied to an operation unit by interposing variable resistors at a predetermined angular interval between a substrate and an operation unit and detecting a change in a resistance value of each variable resistor. Or a force detection device capable of measuring a force distribution, wherein each variable resistor is made of a pair of conductive lands provided on one of a substrate and an operation unit, and a conductive rubber or elastomer provided on the other. A plurality of minute projections are formed on a surface of the contact resistance generating plate facing the pair of conductive lands,
When a force is applied to the operating portion so as to bring the contact resistance generating plate into contact with the pair of conductive lands, the minute protrusions are crushed in accordance with the force, and the contact area between the contact resistance generating plate and the pair of conductive lands is reduced. And a resistance between the pair of conductive lands is reduced accordingly. 2. The magnitude and direction of a force applied to an operation unit by interposing variable resistors at a predetermined angular interval between a substrate and an operation unit and detecting a change in resistance value of each variable resistor. Or a force detection device capable of measuring a force distribution, wherein each variable resistor is provided with a pair of conductive lands provided on one of a substrate or an operation unit, and provided on the other and conductive ink or conductive ink. A contact resistance generating plate made of a non-conductive rubber or a non-conductive elastomer having a large number of minute projections to which a conductive paint is attached, and operating to contact the contact resistance generating plate with a pair of conductive lands. When a force is applied to the portion, the minute projections are crushed in accordance with the force, and the contact area between the contact resistance generating plate and the pair of conductive lands increases, and accordingly, the resistance between the pair of conductive lands decreases. Make it smaller A force detecting device, characterized in that: 3. The force detection device according to claim 1, wherein the variable resistors are provided between the substrate and the operation unit at 180 ° intervals. 4. A variable resistor is provided between the substrate and the operation unit at 90 ° intervals, and a change in a resistance value of the variable resistor causes a force in the XY axis direction acting on the operation unit to change. 3. The force detecting device according to claim 1, wherein the size and the direction or the distribution of the force can be measured. 5. When no force is applied to the operation unit,
A pair of conductive lands and a contact resistance generating plate are separated,
5. The force detecting device according to claim 1, wherein the resistance between the pair of conductive lands is infinite. 6. At the center between the variable resistors, two concentric conductive lands are provided on the substrate to serve as switch terminals, while the button portion of the operation section has a conductive rubber surface, a conductive elastomer surface, and a conductive terminal. A switch plate serving as a switch contact having an ink surface or a conductive paint surface is fixed, and when a force is applied to the button portion so as to bring the contact resistance generating plate into contact with the pair of conductive lands, the switch plate is concentric. The force detecting device according to any one of claims 1 to 5, wherein the force detecting device comes into contact with two conductive lands, and a space between the two conductive lands is closed. 7. The distance between a contact resistance generating plate constituting a variable resistor and a pair of conductive lands is different from the distance between a switch plate and two concentric conductive lands, and the contact resistance generating plate and a pair of conductive lands are different from each other. 7. The force detecting device according to claim 6, wherein the contact timing with the conductive land and the contact timing with the two conductive lands concentric with the switch plate are shifted. 8. The force detecting device according to claim 1, wherein a click feeling can be transmitted to a hand when operated.