JP2006222166A - Variable resistance device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable resistance device which can be constituted compactly in a simple structure, and which is easy to constitute a fail-safe system without requiring to draw around a wire long. <P>SOLUTION: A flexible conductive path 8 which forms a nonlinear state as a whole is provided between two electrodes 3 and 4. The part connected to at least two electrodes 3 and 4 of the flexible conductive path 8 shows an electric resistance of the degree not becoming also in the state that is not deformed, and constitutes from variable resistance elastomers 5 and 6 of an elongated shape having characteristic that an electric resistance falls when a deformation is received. At least the part of the elastomers 5 and 6 is made to extend in the direction which keeps away from both the sides of the two electrodes 3 and 4 in the state that a deformation is not received by the force out of the apparatus 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a variable resistance device that changes its electrical resistance in response to deformation of a predetermined portion, and more particularly to a variable resistance device using a variable resistance elastomer.

Various variable resistance devices that use a variable resistance elastomer such as a variable resistance rubber so that the electrical resistance changes in accordance with the deformation received by the elastomer have been conventionally developed (see, for example, Patent Document 1). ).
Japanese Patent Laid-Open No. 1-110202

  However, this type of conventional variable resistance device has the following problems.

(A) the structure is relatively complex;
(B) When a variable resistance element such as a variable resistance rubber is elongated and electrodes are connected to both ends of the element, the gap between the two electrodes is increased, the length of the device is increased, and at least It is necessary to route the lead wire connected to one electrode for a long time,
(C) Since a general variable resistance rubber has a very high electric resistance in an undeformed state and is an electrical insulator, in a variable resistance device using such a general variable resistance rubber, In both cases of not being deformed and failure conditions such as disconnection, it will be electrically insulated, so an output indicating that it has not undergone deformation will be output even at the time of failure. If this is not taken into consideration, a safety problem arises (however, the invention of Patent Document 1 uses a variable resistance rubber (extension-type conductive rubber) of a kind that does not become an insulator even when not deformed).

  In addition, the problem that the output of the normal operation state and the output of the failure state may not be distinguished from each other as in the above (c) is common to the sensors in general that do not use the variable resistance elastomer. It was a problem.

  The present invention has been made in view of such conventional circumstances, and an object of the present invention is to provide a variable resistance device that can have a simple structure.

  Another object of the present invention is to provide a variable resistance device that can be configured compactly.

  Another object of the present invention is to provide a variable resistance device that is advantageous in mounting without requiring a long lead wire connected to an electrode.

  Another object of the present invention is to provide a variable resistance device that can easily constitute a fail-safe system.

  Still other objects of the present invention will become apparent from the following description.

The variable resistance device according to the present invention has two electrodes and a flexible conductive path which is provided between the two electrodes and electrically connects the two electrodes to each other and which is formed in a non-linear shape as a whole. And
The portions of the flexible conductive path connected to at least the two electrodes, respectively, exhibit an electrical resistance that does not become an electrical insulator even when they are not deformed, and the electrical resistance decreases when they are deformed. It consists of an elongated variable resistance elastomer with properties,
At least a part of the variable resistance elastomer extends in a direction away from both of the two electrodes in a state in which the variable resistance elastomer is not deformed by a force outside the apparatus.

  Specifically, the shape of the flexible conductive path can be substantially U-shaped, for example, in a state where at least the variable resistance elastomer is not deformed by a force outside the apparatus.

  In the present invention, the structure can be simplified by the configuration as described above.

  Further, if the flexible conductive path is linear as a whole, the length of the device becomes long and the gap between the two electrodes becomes large, and it is necessary to draw a conductive wire connected to at least one electrode long, Although this is disadvantageous in terms of mounting, in the present invention, since the flexible conductive path is non-linear, it can be configured compactly, and the gap between the two electrodes can be reduced, so that the conductive wire connected to the electrode can be lengthened. This eliminates the need for routing and is advantageous in terms of mounting.

  In the present invention, since the variable resistance rubber exhibits an electrical resistance that does not become an electrical insulator even in a state where it is not deformed, it is easy to distinguish from a failure such as a disconnection that becomes an insulating state, Easy to configure fail-safe system.

The variable resistance device of the present invention is
(B) It can be a simple structure,
(B) It can be configured compactly.
(C) There is no need to route the lead wire connected to the electrode long, which is advantageous for mounting.
(D) Easy to configure fail-safe systems.
It is possible to obtain excellent effects such as.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

  1 and 2 show a variable resistance device 1 according to a first embodiment of the present invention. Two short round bar-like electrodes 3 and 4 are fixed to a plate-like electrode support 2 made of an electrical insulator such as plastic in a state of penetrating in a vertical direction with respect to the electrode support 2. . One end sides of two tube-like variable resistance elastomers 5 and 6 are fitted on the outer circumference of one end (lower end in FIG. 1) of each electrode 3 and 4. The other end sides of the variable resistance elastomers 5 and 6 are respectively fitted to the outer circumferences of both ends of the relay conductive material 7 made of a conductive material such as a metal having a circular cross section and generally U-shaped or U-shaped as a whole. It is worn. Here, the two variable resistance elastomers 5 and 6 and the relay conductive material 7 constitute a flexible conductive path 8 that electrically connects the two electrodes 3 and 4 to each other. 8 is generally U-shaped when at least the variable resistance elastomers 5 and 6 are not deformed by a force outside the variable resistance device 1. However, the two variable resistance elastomers 5 and 6 are linearly extended when not deformed by a force outside the device 1.

  The variable resistance elastomers 5 and 6 are made of the same variable resistance elastomer material. FIG. 3 is a characteristic diagram showing the relationship between the elongation ratio and the change in electrical resistance when the variable resistance elastomer material is stretched (however, this characteristic diagram shows a variable resistance elastomer material having a length of 50.0 mm and a width). 30.0 mm and thickness 0.3 mm). As is apparent from this characteristic diagram, the variable resistance elastomer material has a high electrical resistance that does not become an electrical insulator in a state where no elongation is given, and the electrical resistance increases as the given elongation increases. Has a characteristic of decreasing. In this variable resistance elastomer material, the change in electrical resistance with respect to the change in elongation (force) is smooth, the relationship between elongation (force) and electrical resistance is stable, and hysteresis is small.

  The variable resistance elastomer material has a characteristic that when it is compressed or twisted, the electrical resistance decreases as the deformation increases, as in the case of stretching.

  As the variable resistance elastomer material exhibiting such characteristics, for example, the variable resistance rubber (extension type conductive rubber) previously disclosed by the present inventor in JP-A-4-304266 or JP-A-64-48306 is used. Can do. However, as the variable resistance elastomer in the present invention, if it has a characteristic that the electrical resistance does not become an electrical insulator even in a state where it is not deformed, and the electrical resistance decreases when it is deformed, the above publication discloses Rubbers other than those disclosed and elastomers other than rubber can also be used.

  The variable resistance elastomers 5 and 6 have a uniform inner diameter and outer diameter in a free state in which they are not subjected to any external force and are not deformed before being fitted to the electrodes 3 and 4 and the relay conductive material 7. And it is in a straight state. The inner diameters of the variable resistance elastomers 5 and 6 in the free state and the outer diameters of the electrodes 3 and 4 and the relay conductive material 7 are the same as the inner diameters of the variable resistance elastomers 5 and 6 in the free state. It is smaller than the outer diameter of the relay conductive material 7, and the portions where the variable resistance elastomers 5 and 6 are attached to the electrodes 3 and 4 and the relay conductive material 7 are extended by about 40%, that is, the variable resistance elastomers 5 in these fitting portions. It is preferable to set so that the electric resistance of 6 is sufficiently lowered. Thereby, the electrical resistance of the variable resistance elastomers 5 and 6 in the fitting portion can be prevented from adversely affecting the operation of the apparatus.

  Next, the operation of this embodiment will be described. In this variable resistance device 1, in a state where it is not deformed by a force outside the device 1, the variable resistance elastomers 5 and 6 are in a state of extending linearly as shown in FIG. , 6, the electrical resistance of the portions not fitted to the electrodes 3, 4 and the relay conductive material 7 (hereinafter referred to as non-fitted portions 5 a, 6 a), and the electrical resistance between the electrodes 3, 4, is an electrical insulator. The value is high enough not to be.

  However, if the force outside the device 1 acts on the non-insertion portions 5a and 6a of the variable resistance elastomers 5 and 6 via the relay conductive material 7 or directly, the non-insertion portions 5a and 6a are deformed. The electrical resistance of the resistance elastomers 5 and 6 as a whole, and consequently the electrical resistance between the electrodes 3 and 4, decreases according to the magnitude of deformation of the non-inserted portions 5a and 6a. Therefore, the variable resistance device 1 can be used as various sensors for detecting various states or physical quantities.

  FIG. 4 shows an example of how the variable resistance device 1 is bent. In this example of use, as shown in (a), before the movable body 9 such as a door passes, the non-fitting portions 5a and 6a of the variable resistance elastomers 5 and 6 are not deformed and are straight. Since it is in a state, the electrical resistance between the electrodes 3 and 4 has a high value.

  However, when the movable body 9 tries to pass the installation position of the variable resistance device 1 while contacting the variable resistance elastomers 5 and 6 and the relay conductive material 7 as shown in FIG. Since the landing portions 5a and 6a are bent and deformed, the electrical resistance between the electrodes 3 and 4 is lowered.

  When the movable body 9 passes through the installation position of the variable resistance device 1 and the variable resistance device 1 becomes free from the movable body 9 as shown in (c), the variable resistance elastomers 5 and 6 are again straight. The electric resistance between the electrodes 3 and 4 becomes a high value again. Thereby, it can be detected whether the movable body 9 passed the predetermined position.

  Therefore, for example, if the door is the movable body 9, the opening and closing of the door can be detected. Moreover, it can also be used as a door pinching detection sensor as follows. That is, if the position of (a) is set to the position where the door is open, the position of (b) is set to the position immediately before the door is completely closed, and the position of (c) is set to the position where the door is completely closed, Is not pinched by the door, the resistance value between the electrodes 3 and 4 decreases for a short time at the position (b) and then returns to a high value, but when a person or the like is pinched, Since the door stops at the position (b) for a long time, the resistance value between the electrodes 3 and 4 decreases for a long time. Therefore, it is possible to detect the pinching of the door by detecting a decrease in the resistance value between the electrodes 3 and 4 that continues for a certain period of time.

  FIG. 5 shows an example of usage that undergoes another bending, and is an example in which this variable resistance device 1 is used as a liquid level sensor. In this usage example, the float 10 is attached to the relay conductive material 7, and the float 10 is floated on the liquid surface 11. Accordingly, the non-fitting portions 5a and 6a of the variable resistance elastomers 5 and 6 are bent and deformed as the liquid level 11 is raised and lowered. Can be detected.

  FIGS. 6 and 7 show an example of usage that receives torsion of the variable resistance device 1. In this usage example, a thin plate-like blade 12 is attached to the relay conductive material 7. As a result, when a force outside the device 1 acts on one side of the blade 12 as shown by an arrow A in FIG. 7, the non-fitting portions 5a and 6a of the variable resistance elastomers 5 and 6 undergo torsional deformation. Therefore, the force can be detected based on a change in electrical resistance between the electrodes 3 and 4.

  If the blades 12 are placed in a gas or liquid flow, the non-fitting portions 5a and 6a of the variable resistance elastomers 5 and 6 are formed according to the flow of the gas or liquid, as in FIGS. Subject to bending deformation. Therefore, the variable resistance device 1 can be used as a flow sensor that detects the flow of a liquid based on a change in electrical resistance between the electrodes 3 and 4.

  The variable resistance device 1 can be used in modes other than the usage modes as described above. For example, it can be used as a vibration sensor, or can be used as a magnetic sensor by attaching a magnetic body or the like to the relay conductive material 7. Moreover, the variable resistance elastomers 5 and 6 can also be used in such a manner that they are stretched by being pulled in their length direction.

  Further, in the present invention, the variable resistance elastomers 5 and 6 are not necessarily formed in a tube shape, and may be a solid shape such as a circular cross-section, a quadrangle, or a polygon. If an attempt is made to connect to the electrodes 3, 4 or the relay conductive material 7 by a simple tightening structure, there arises a problem that the electrical resistance of the connection portion becomes unstable, and cracks are likely to occur in the variable resistance elastomers 5, 6. However, if the variable resistance elastomers 5 and 6 are formed in a tube shape as in this embodiment, such inconvenience can be prevented. The electrical resistance of the variable resistance elastomers 5 and 6 in these tightening target portions is sufficiently lowered and then tightened to stabilize the electrical resistance of the connecting portion).

  In this embodiment, the length L (see FIG. 1) of the non-fitting portions 5a and 6a of the variable resistance elastomers 5 and 6 is usually equal to the inner diameter of the variable resistance elastomers 5 and 6 in a free state. About 1 to 3 times is preferable. This is because, when the length L is too long, the deformation ratio that the variable resistance elastomers 5 and 6 receive during operation becomes small, and thus a sufficiently large resistance change cannot be obtained.

  Further, if the flexible conductive path 8 is configured to extend linearly, the length of the device 1 is increased, and the gap between the two electrodes 3 and 4 is increased, so that it is connected to at least one of the electrodes 3 or 4. However, in this variable resistance device 1, the flexible conductive path 8 is generally U-shaped, so that the device can be made compact. In addition, since the gap between the two electrodes 3 and 4 can be reduced, it is not necessary to draw a long lead wire connected to the electrodes 3 and 4, which is advantageous in mounting.

  Further, in this variable resistance device 1, since the variable resistance elastomers 5 and 6 exhibit an electrical resistance high enough not to be an electrical insulator even in a state where they are not deformed, a failure such as a broken wire that becomes an insulating state. It is easy to discriminate from the time, and it is easy to construct a fail-safe system (if a voltage is applied between the electrodes 3 and 4, a weak current is applied to the variable resistance elastomers 5 and 6 even when no deformation is applied. Is flowing).

  FIG. 8 shows a second embodiment of the present invention. In the present embodiment, the flexible conductive path 8 having a substantially U shape is composed of only one tube-shaped variable resistance elastomer 13, and the relay conductive material 7 in the first embodiment is not provided.

  In the present embodiment, since the relay conductive material 7 is not provided, the configuration can be further simplified as compared with the first embodiment.

However, when using the variable resistance elastomer 13 that is straight when not receiving external force, the portion of the variable resistance elastomer 13 that should cause a change in resistance value is always deformed. As a result, the range of change in resistance value that can be used is narrowed and the elastomer 13 is easily fatigued (in the first embodiment, such inconvenience can be prevented). However, such inconvenience can be prevented by forming the variable resistance elastomer 13 in a generally U shape from the beginning so that the variable resistance elastomer 13 is not deformed when not receiving external force from outside the apparatus.

In each of the above embodiments, the flexible conductive path 8 is generally U-shaped as a whole. However, in the present invention, the shape of the flexible conductive path is substantially the same as the case where the flexible conductive path is generally U-shaped. It is sufficient that the shape fulfills the same function. That is, the shape of the flexible conductive path may be non-linear as a whole, and at least a part of the variable resistance elastomer constituting the conductive path may extend in a direction away from both of the two electrodes. For example, it may be generally W-shaped, M-shaped or arc-shaped.

  As described above, the variable resistance device according to the present invention is useful as various sensors.

It is a longitudinal cross-sectional view which shows Example 1 of the variable resistance apparatus by this invention. It is a top view which shows the said Example 1. FIG. It is a characteristic view which shows the relationship between the elongation rate at the time of giving the elongation of the variable resistance elastomer in the said Example 1, and an electrical resistance. It is operation | movement explanatory drawing which shows the usage example which receives bending of the variable resistance apparatus of the said Example 1. FIG. It is operation | movement explanatory drawing which shows the other usage condition example which receives bending of the variable resistance apparatus of the said Example 1. FIG. It is a front view which shows the usage example which receives the twist of the variable resistance apparatus of the said Example 1. FIG. It is operation | movement explanatory drawing which shows the usage example which receives the twist of the variable resistance apparatus of the said Example 1. FIG. It is a longitudinal cross-sectional view which shows Example 2 of the variable resistance apparatus by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Variable resistance apparatus 3, 4 Electrode 5, 6 Variable resistance elastomer 7 Relay conductive material 8 Flexible conductive path 13 Variable resistance elastomer

Claims (8)

Two electrodes, and a flexible conductive path which is provided between these two electrodes and electrically connects the two electrodes to each other and forms a non-linear shape as a whole,
The portions of the flexible conductive path connected to at least the two electrodes, respectively, exhibit an electrical resistance that does not become an electrical insulator even when they are not deformed, and the electrical resistance decreases when they are deformed. It consists of an elongated variable resistance elastomer with properties,
The variable resistance device, wherein at least a part of the variable resistance elastomer extends in a direction away from both of the two electrodes in a state in which the variable resistance elastomer is not deformed by a force outside the device. The flexible conductive path is a variable resistance device that is generally U-shaped at least when the variable resistance elastomer is not deformed by a force outside the device. The flexible conductive path has two variable resistance elastomers connected to the two electrodes, respectively, and a relay conductive material electrically connected between the two variable resistance elastomers. The variable resistance device according to claim 1, wherein the two variable resistance elastomers are in a state of extending linearly when not deformed by a force outside the device. The variable resistance device according to claim 3, wherein the variable resistance elastomer has a tube shape and is fitted to an outer periphery of the relay conductive material. The variable resistance device according to claim 1, wherein the flexible conductive path is constituted by a single variable resistance elastomer. The variable resistance device according to claim 1, wherein the variable resistance elastomer has a tube shape and is fitted to an outer periphery of the electrode. The variable resistance device according to claim 1, 2, 3, or 5, wherein the variable resistance elastomer is solid. The variable resistance device according to any one of claims 1 to 7, wherein the variable resistance elastomer has a characteristic that when the elongation is given, the electric resistance changes according to the magnitude of the elongation.

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