JP2001050706A - Extension sensitive element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize an element by forming an extension conductive resistor connecting both the end parts to terminals for measuring a change of an electric resistance value so as to dispersedly blend conductivity giving material in non- conductive elastomer. SOLUTION: This extension sensitive element is provided with measuring terminals 2, 3 and an extension conductive resistor 4 connecting both the end parts with the terminals 2, 3 as fundamental constitution. The extension conductive resistor 4 is constituted so that conductivity giving material is dipersedly blended in non-conductive elastomer, the electric resistance is reduced at extension, and when the extended load is released, the electric resistance is returned to the intial state. As for non-conductive elastomer substance constituted of liquid silicone rubber and silicone adhesive is mentioned. As for conductivity giving material, conductive vitrified micro spherical carbon particle is mentioned. Such materials is formed into a cylindrical shape or bar shape to obtain an extension conductive resistor 4. The measuring terminals 2, 3 are connected to the terminals of an electric resistance measuring device, and one measuring terminal 2 is a movable terminal moving according to elongation of an object, and the other terminal 3 is unmovable terminal unmovable against the object.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extension sensing element, and more particularly, to an extension conductive element, which can reliably measure an extension amount of an object and an extension stress acting on the object, and an amplifier or the like. The present invention relates to a small-sized extension sensing element that does not require a separate device, and to a extension sensing element that can measure a change in distance between two objects and a force that tends to separate two objects from each other.

[0002]

2. Description of the Related Art Among instruments for measuring the extensional strain of an object, there is an electric resistance strain gauge which is widely used because it measures strain electrically and is relatively easy to handle. The conventional electric resistance strain gauge has a so-called strain gauge formed by sticking a metal resistance wire on an insulating mount as an extension sensing element. When this strain gauge is attached to the surface of the object with an adhesive and an elongation force is applied to the object in this state, the electric resistance value of the resistance wire changes according to the elongation. Since there is a certain correlation between the electric resistance of the resistance wire and the elastic elongation of the resistance wire, if the change in the electric resistance is measured, the elongation of the object can be calculated based on the change. In addition, since the stress can be calculated from the amount of extension when the elastic modulus of the material of the object is known, the strain gauge could also be used to measure the elongation stress acting on the object. Note that, for example, a nichrome wire is used as the resistance wire.

[0003]

However, the above-mentioned prior art has the following problems. That is, the strain gauge in the electric resistance strain gauge has an advantage that it is relatively easy to handle, but has a small change in the electric resistance value with respect to the elongation of the object. Therefore, in order to amplify the amount of change to a measurable level, it is necessary to separately provide a signal amplifying device including an amplifier and an AC bridge circuit. Since this signal amplifier occupies a relatively large space, there is a problem that the entire strain gauge becomes large. In addition, since metal wires such as nichrome wires have a relatively narrow elastic range and relatively small elastic strain, strain gauges using such metal wires have a narrow measurable range of the amount of elongation and elongation stress, and the It was not suitable for measurement when the elongation was large. Also, since a strain gauge is used by attaching it to the surface of one object, it can measure the change in the distance between two objects and the force that causes two objects to move away from each other. Did not.

[0004] The present invention has been made in view of such circumstances, and uses an extension conductive resistor to increase the amount of elongation of an object.
An object of the present invention is to provide a small extension sensing element which can reliably measure an extension stress acting on an object and does not require a separate device such as an amplifier.

[0005]

According to the first aspect of the present invention,
It consists of a pair of measuring terminals for measuring a change in electric resistance value, and an elongated conductive resistor having both ends connected to these terminals, and the resistor is made of a non-conductive elastomer in a conductivity-imparting material. Are dispersed and blended. In the invention according to claim 2, the pair of terminals are respectively fitted and connected to holes formed in the elongated conductive resistor, and an outer peripheral portion of each terminal is pressed against an inner peripheral surface of the hole. The extension sensing element according to claim 1, wherein a protrusion for preventing slippage is formed. The invention according to claim 3 is that, of the pair of terminals, one terminal is fixed to the first terminal holding portion, and the other terminal is moved by the second terminal holding portion in the extending direction of the extended conductive resistor. The second terminal holding portion is slidably held, and has a sliding holding surface along the outer peripheral shape of the other terminal having a non-circular cross section. Is an extension sensing element.

According to a fourth aspect of the present invention, of the pair of terminals, one of the terminals is fixed to the first terminal holding portion, and the other terminal is connected to the extended conductive resistor by the second terminal holding portion. The other terminal is slidably held in the extension direction, and an extension stopping protrusion is formed on an outer peripheral portion of the other terminal. The extension stopping protrusion is formed on the second terminal in a state where the resistor is extended by a predetermined length. The extension sensing element according to claim 1, wherein the extension sensing element is configured to interfere with the holding portion. In the invention according to claim 5, one of the pair of terminals is fixed to a first terminal holding portion, and the other terminal is moved by a second terminal holding portion in a direction in which the elongated conductive resistor extends. Slidably held, the elongated conductive resistor has an inner diameter larger than the maximum diameter of the resistor and is covered with an electrically insulating tubular cover material,
2. The extension sensing element according to claim 1, wherein the first terminal holding portion is provided on one end side of the tubular cover material, and the second terminal holding portion is provided on the other end side. 3. In the invention according to claim 6, one of the pair of terminals is fixed to a first terminal holding portion, and the other terminal is moved by a second terminal holding portion in an extending direction of the elongated conductive resistor. The load reducing elastic body is slidably held between the second terminal holding portion and the end of the elongated conductive resistor on the second terminal holding portion side. 2. The extension sensing element according to item 1. By providing these inventions,
The above problems are completely solved.

[0007]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view showing an extension sensing element according to the present invention. FIG. 2 is a sectional view showing the element. 3 to 9 are perspective views showing members constituting the element. Extension sensing element (1) according to the present invention
Is an elongation sensing element used in an electric resistance strain meter or the like, and the amount of elongation of an object, the elongation stress acting on the object, and the distance between two objects based on a change in resistance when the electric resistor is expanded. And the force with which two objects move away from each other can be measured. This extension sensing element (1)
Is a pair of measuring terminals (2) and (3) for measuring a change in electric resistance, and an elongated conductive resistor (4) having both ends connected to these terminals (2) and (3). And a pair of terminal holding portions (5) and (6) and a cylindrical cover member (7) as other configurations. Hereinafter, these components will be sequentially described in detail.

The stretched conductive resistor (4) is an elastic resistor having a property that the electrical resistance decreases as the amount of extension increases. The elongated conductive resistor (4) is obtained by dispersing and blending a conductivity-imparting material in a non-conductive elastomer. With the configuration in which the conductivity-imparting material is dispersed and blended in the non-conductive elastomer, the conductivity-imparting materials come close to or come into contact with each other at the time of elongation, and in some cases, dielectric breakdown occurs, and the electric resistance is suitably reduced. In addition, when the stretched conductive resistor (4) returns to its original length by releasing the stretching load, the position of the conductivity imparting material returns to its original position, and as a result, the electrical resistance value also returns to its original value.

The specific constitution of the material of the elongated conductive resistor (4) having such properties is not particularly limited. Examples of the non-conductive elastomer include liquid silicone rubber and silicone. Examples thereof include varnishes, silicone raw rubbers, and silicone adhesives containing these as a main component. Examples of the conductivity-imparting material include conductive glass-like fine spherical carbon particles obtained by heat-treating fine spherical particles made of a phenol resin or the like in a vacuum.

By forming such a material into a cylindrical shape or a rod shape, an elongated conductive resistor (4) as illustrated in FIG. 3 can be obtained. In the case of a cylindrical shape, in the case of a rod shape, the cross-sectional shape is not particularly limited, but in the case of a cylindrical shape, for example, it can be formed into a cylindrical shape, a square cylindrical shape, or a semi-cylindrical shape. In the case of a columnar shape, for example, it can be formed into a columnar shape, a square columnar shape, or a semi-columnar shape. Note that, in the illustrated example, the shape is cylindrical.

The pair of measuring terminals (2) and (3) are connected to both terminals (not shown) of the electric resistance measuring instrument. Of these measuring terminals (2) and (3), one measuring terminal (2) is a movable terminal that moves according to the elongation of the object (see FIGS. 10 and 11), and the other measuring terminal ( 3) is an immobile terminal that is immovable with respect to the object. In the following description, the one measuring terminal (2) will be referred to as a movable terminal (2), and the other measuring terminal (3) will be referred to as an immobile terminal (3). The terminal holding part (5) (corresponding to the second terminal holding part in the present invention) for holding the movable terminal holding part (5) and the terminal holding part (6) for holding the immobile terminal (3) (the second terminal holding part in the present invention) (Corresponding to one terminal holding portion) is referred to as an immobile terminal holding portion (6).

The immobile terminal (3) is a rod-shaped member as shown in FIG. 5, and has a male screw part (8) and a held part ( 9), a holding projection (10) and a detachment prevention projection (11) are formed. The material of the immobile terminal (3) is not particularly limited. For example, copper or brass plated with nickel or gold, or stainless steel can be used, but stainless steel is used in terms of strength and corrosion resistance. It is desirable to use steel. The external thread portion (8) is a portion to be screwed with the nut (12). By screwing the male screw portion (8) and the nut (12), the immobile terminal holding portion (6) is held between the nut (12) and the holding projection (10). Thereby, the fixed terminal (3) can be fixed to the fixed terminal holding part (6). In the illustrated example, the nut (1
An end of a terminal connection plate (13) is provided between the terminal connection plate (2) and the immobile terminal holding portion (6), and the male screw portion (8) and the nut (12) are screwed into the terminal connection plate (13). The end of the plate (13) can be clamped and fixed.

The held part (9) is a fixed terminal holding part (6).
This is the part that is held. The held portion (9) is inserted into the through hole (14) (see FIG. 7) of the stationary terminal holding portion (6). The cross-sectional shape of the held portion (9) is not particularly limited, but is, for example, a circular shape.

The holding projection (10) is a portion for holding the immobile terminal holding portion (6) together with the nut (12), and is in contact with one end surface of the immobile terminal holding portion (6). Although the shape of the holding projection (10) is not particularly limited,
In the illustrated example, it is formed in a ring shape.

The detachment-preventing projection (11) is a part for preventing the elongated conductive resistor (4) from falling off the end of the movable terminal (2). The protrusion (11) for preventing the detachment is
A resistor mounting part (1) formed at one end of the movable terminal (2)
5) It is formed in the middle part. Resistor mounting part (15)
The diameter of the hole (16) of the elongated conductive resistor (4) (FIG. 3)
(See reference). As a result, the elongated conductive resistor (4) can be mounted in close contact with the end of the resistor mounting portion (15). Further, since the protrusion (11) for preventing the detachment is formed so as to protrude from the peripheral surface of the resistor mounting portion (15), it is pressed against the inner peripheral surface of the elongated conductive resistor (4). Therefore, the protrusion (11) for preventing the detachment is provided.
Can reliably prevent the elongated conductive resistor (4) from falling off from the resistor mounting portion (15).

The immobile terminal holding portion (6) is provided with an immobile terminal (3).
And is a cylindrical body as shown in FIG. The stationary terminal holding portion (6) has the through hole (14) as described above, and the through hole (1) is provided.
The held portion (9) of the immobile terminal (3) is inserted into 4). And the immobile terminal (3) can be fixed to the immobile terminal holding part (6) by tightening the nut (12). The shape of the inner surface of the through hole (14) is not particularly limited, and may be any shape such as a circular shape or a polygonal shape. In the illustrated example, the shape is a circular shape. Further, the immobile terminal holding portion (6) is inserted and fixed to the end of the cylindrical cover member (7) covering the elongated conductive resistor (4) by an adhesive or the like.

The movable terminal (2) is a rod-shaped member as shown in FIG. 6, and has a male screw part (17) and a held part ( 18), a projection (19) for stopping the extension, and a projection (20) for preventing falling off. The male screw part (17) has a nut (21),
This is the portion that is screwed with (22). By screwing the male screw part (17) and the nuts (21) and (22), the end of the terminal connection plate (13) provided between the nuts (21) and (22) is connected to the movable terminal (2). ) Can be fixed. The nut (22) defines the movable range of the movable terminal (2). The movable terminal (2) is moved from the state shown in FIGS. 10 and 11 to the state shown in FIG.
That is, the nut (22) can be moved to a position where it comes into contact with the movable terminal holding portion (5).

The held portion (18) is a portion held by the movable terminal holding portion (5). This held part (18)
Is formed longer than the length of the movable terminal holding portion (5),
Moreover, its cross-sectional shape is non-circular. The inner peripheral surface of the through hole (23) (see FIG. 8) of the movable terminal holding portion (5)
The holding portion (18) is shaped to be in contact with the peripheral surface, and its cross-sectional shape is non-circular. Accordingly, the held portion (18) can slide in the through hole (23) of the movable terminal holding portion (5), and the rotation in the circumferential direction in the through hole (23) is prevented. In the illustrated example,
Although the cross-sectional shape of the held portion (18) is a substantially square shape, the present invention is not limited to this, and may be, for example, another polygonal shape.

The extension stopping projection (19) is a portion for suppressing the extension of the extension conductive resistor (4). When the extension conductive resistor (4) is extended to a predetermined length (see FIG. 11), the extension stopping projection (19) is formed on the periphery of the through hole (23) of the movable terminal holding portion (5). It is designed to interfere. Thereby, the extension stopping projection (19) can suppress the extension of the extension conductive resistor (4). In the illustrated example, the extension-reducing convex portion (19) is formed in a ring shape. However, the present invention is not limited to this shape, and may be, for example, a columnar protrusion.

The protrusion (20) for preventing detachment is a portion for preventing the extended conductive resistor (4) from coming off the end of the movable terminal (2). The form of the detachment preventing protrusion (20) is the same as that of the detachment preventing protrusion (11) of the immobile terminal (3).

The movable terminal holding section (5) includes a movable terminal (2).
Are slidably held in the extending direction of the elongated conductive resistor (4), and as shown in FIG. 2, the movable terminal (2)
Is a tubular body shorter than the length of the held portion (18). The movable terminal holding portion (5) has the through hole (23) as described above, and the held portion (18) of the movable terminal (2) is inserted into the through hole (23). As described above, the cross-sectional shape of the movable terminal (2) is non-circular, and the inner surface of the through hole (23) of the held portion (18) is also shaped accordingly. Therefore, the movable terminal (2) is slidable in the axial direction and is prevented from rotating in the circumferential direction.

The tubular cover member (7) covers the elongated conductive resistor (4). As shown in FIG. 2, the inner diameter of the tubular cover member (7) is set to be larger than the maximum diameter of the elongated conductive resistor (4), and is made of an electrically insulating material. Thereby, the expansion and contraction operation of the elongated conductive resistor (4) can be smoothly performed, and even if the elongated conductive resistor (4) hits the cover material (7), no leakage occurs, and the elongated conductive resistor (4) does not leak. It is possible to accurately measure the resistance value of the body (4). The cross-sectional shape of the tubular cover member (7) is not particularly limited, and may be, for example, a circular shape or a polygonal shape, but is circular in the example shown in FIG. Also, the material of the cylindrical cover member (7) is not particularly limited as long as it is an electrically insulating material. For example, a thermoplastic resin such as a polycarbonate resin, a polyacetal resin, an acrylic resin, a nylon resin, or the like; Curable resin can be adopted,
To further improve the heat resistance, glass or ceramic can be used.

The terminal connecting plate (13) is attached to the movable terminal (2), and is directly connected to both terminals (not shown) of the electric resistance measuring instrument. The shape of the terminal connection plate (13) is not particularly limited, but in the example shown in FIG. 9, it is formed in a substantially L-shape composed of two pieces, and one of the pieces has a movable terminal ( A hole (24) through which the male screw portion (8) of 2) is inserted is formed, and a hole (2) through which the terminal of the electric resistance measuring instrument is inserted is formed in the other portion.
5) is formed. The terminal connection plate (1
3) can be fixed to an object to be measured such as strain using an adhesive or the like, and thereby, the amount of elongation between two points, the elongation stress, and the like of the object can be measured. The terminal connection plate (13) is similarly attached to the immobile terminal (3).

Next, a method of using the extension sensing element (1) just described will be described. First, a case of measuring the amount of elongation and elongation stress between two points in one object will be described. Both terminals (not shown) of the electric resistance measuring instrument are connected to the holes (25) of the terminal connection plate (13). Then
Object to measure the amount of elongation and elongation stress (not shown)
Then, a terminal connection plate (13) is attached using an adhesive or the like. Then, an extension load is applied to the object. Then, an elongation strain occurs in the object due to the elongation load,
The terminal connection plate (13) and the movable terminal (2) move in response to the strain, and the elongated conductive resistor (4) expands. When the stretched conductive resistor (4) expands, its electrical resistance changes. Therefore, the correlation between the known resistance value of the stretched conductive resistor (4) and the elastic extension of the resistor (4) is determined. Based on this, the extension amount of the object can be calculated. Also,
If the elastic modulus of the object is known, the elongation stress can be calculated from the already calculated elongation.

If there is a graph showing the correlation between the resistance value of the elongated conductive resistor (4) and the elastic elongation of the resistor (4), the resistance value of the elongated conductive resistor (4) is After reading, the amount of elongation and elongation stress can be calculated by referring to the graph, but by connecting an electric resistance measuring device to a microcomputer (not shown) that performs an operation based on this correlation. , May be calculated automatically.

Next, a description will be given of a case in which a change in the distance between two objects and a force in which one object moves away from the other object are measured. Both terminals (not shown) of the electric resistance measuring instrument are connected to the holes (25) of the terminal connection plate (13). Next, a terminal connection plate (13) is attached to each of two objects (not shown) to be measured using an adhesive or the like. Then, a load is applied to one object in a direction away from the other object. Then, the terminal connection plate (13) and the movable terminal (2) are moved by the load.
Moves, and the elongated conductive resistor (4) expands. When the stretched conductive resistor (4) is stretched, its electrical resistance changes. Therefore, the correlation between the known resistance value of the stretched conductive resistor (4) and the stretching load applied to the resistor (4). Can be used to calculate a force that causes one object to move away from the other object. In addition, if the elastic modulus of the elongated conductive resistor (4) is known, the change in the distance between the two objects can be calculated from the already calculated stretch load.

If there is a graph showing the correlation between the resistance value of the elongated conductive resistor (4) and the extension load applied to the resistor (4), the resistance value of the elongated conductive resistor (4) After reading the data, it is possible to calculate a change in the distance between the two objects by referring to the graph, but a microcomputer (not shown) that performs an operation based on this correlation has an electric resistance measuring device. May be automatically calculated by connecting.

FIGS. 12 and 13 are sectional views showing another embodiment of the extension sensing element (1) according to the present invention. This embodiment is different from the above-described embodiment in that a load reducing elastic body (26) is interposed between the movable terminal holding portion (5) and the projection (19). By disposing the load-reducing elastic body (26), even if a large extension load is applied to the movable terminal (2), a part of the load is absorbed by the load-reducing elastic body (26), and the extension conductive material is extended. The force acting on the resistive element (4) can be reduced. In addition,
FIG. 12 shows a state before an extension load is applied to the movable terminal (2), and FIG. 13 shows a state when an extension load is applied to the movable terminal (2). The form of the load reducing elastic body (26) is not particularly limited, but is a coil spring in the illustrated example. When a coil spring is used, for example, a stainless steel wire, a spring steel wire, a piano wire, a phosphor bronze wire, or the like can be used as the material, but a stainless steel wire is used in terms of oxidation and corrosion resistance. It is desirable to do.

[0029]

According to the first aspect of the present invention, since the stretch sensing element uses a stretch conductive resistor obtained by dispersing and blending a conductivity-imparting material in a non-conductive elastomer, the stretch amount of the object is small. Even so, a change in the amount of extension can be detected as a relatively large change in resistance value. Therefore, this elongation sensing element can provide an accurate elongation amount, elongation stress,
Alternatively, the extension load can be measured, and the entire strain gauge can be significantly reduced in size. In addition, since this stretched conductive resistor has a much wider elastic range and a larger elastic strain than a metal wire, the measurable area of the amount of extension and the extensional load is greatly expanded, and when these values are large. Even if there is, it can be measured reliably.

The extension sensing element according to the second aspect is the first aspect.
In the stretch sensing element described, each of the pair of terminals is
The terminal is fitted and connected to the hole formed in the elongated conductive resistor, and the outer peripheral portion of each terminal has a structure in which a protrusion for preventing detachment that is pressed against the inner peripheral surface of the hole is formed. Therefore, even if a large extension force acts on the extension conductive resistor, the resistor does not fall out of the terminal.

According to a third aspect of the present invention, there is provided an extension sensing element.
In the extension sensing element, one of the pair of terminals is fixed to the first terminal holding portion, and the other terminal is slidable in the extension direction of the extension conductive resistor by the second terminal holding portion. And the second terminal holding portion has a structure having a sliding holding surface along the outer peripheral shape of the other terminal having a non-circular cross section. Can be stretched by faithfully following the extension amount of. Further, even if a twisting force acts on the other terminal, the rotation of the terminal is regulated by the sliding holding surface, so that no twisting force acts on the elongated conductive resistor, and the resistor is damaged. Can be prevented.

According to a fourth aspect of the present invention, there is provided an extension sensing element.
In the extension sensing element, one of the pair of terminals is fixed to the first terminal holding portion, and the other terminal is slidable in the extension direction of the extension conductive resistor by the second terminal holding portion. Is formed on the outer peripheral portion of the other terminal, and the extension-stopping convex portion interferes with the second terminal holding portion in a state where the resistor is extended by a predetermined length. Therefore, the stretched conductive resistor can stretch and follow the stretch amount of the object faithfully. In addition, even if the amount of extension of the object is large, the extension-stopping projection interferes with the second terminal holding portion and the extension of the extended conductive resistor is suppressed, so that it is possible to prevent the resistor from being damaged. it can.

The extension sensing element according to the fifth aspect is the first aspect.
In the extension sensing element, one of the pair of terminals is fixed to the first terminal holding portion, and the other terminal is slidable in the extension direction of the extension conductive resistor by the second terminal holding portion. The elongated conductive resistor is covered by an electrically insulating tubular cover material having an inner diameter larger than the maximum diameter of the resistor, and a first terminal holding portion on one end side of the tubular cover material. Since the second terminal holding portion is provided on the other end side, the elongated conductive resistor can be smoothly expanded and contracted in the cover material while being protected by the cylindrical cover material. Accordingly, the follow-up performance of the elongated conductive resistor can be sufficiently exhibited.

According to a sixth aspect of the present invention, there is provided an extension sensing element.
In the extension sensing element, one of the pair of terminals is fixed to the first terminal holding portion, and the other terminal is slidable in the extension direction of the extension conductive resistor by the second terminal holding portion. The structure is such that the load reducing elastic body is interposed between the second terminal holding portion and the second terminal holding portion side end of the elongated conductive resistor, so that the other terminal is Even when a large extension load is applied, a part of the load is absorbed by the load reducing elastic body, and the force acting on the extension conductive resistor can be reduced. Therefore, the load measurement range of the extension sensing element can be expanded.

[Brief description of the drawings]

FIG. 1 is a front view showing an extension sensing element according to the present invention.

FIG. 2 is a sectional view showing an extension sensing element according to the present invention.

FIG. 3 is a perspective view showing an elongated conductive resistor according to the present invention.

FIG. 4 is a perspective view showing a tubular cover member according to the present invention.

FIG. 5 is a perspective view showing a measurement terminal (immobile terminal) according to the present invention.

FIG. 6 is a perspective view showing a measurement terminal (movable terminal) according to the present invention.

FIG. 7 is a perspective view showing a first terminal holding portion (an immobile terminal holding portion) in the present invention.

FIG. 8 is a perspective view showing a second terminal holding section (movable terminal holding section) in the present invention.

FIG. 9 is a perspective view showing a terminal connection plate according to the present invention.

FIG. 10 is a sectional view showing the operation of the extension sensing element according to the present invention.

FIG. 11 is a sectional view showing the operation of the extension sensing element according to the present invention.

FIG. 12 is a cross-sectional view showing another embodiment of the extension sensing element according to the present invention.

FIG. 13 is a sectional view showing another embodiment of the extension sensing element according to the present invention.

[Explanation of symbols]

 1 ····· Extension sensing element 2 ····· Measurement terminal (movable terminal) 3 ····· Measurement terminal (immobile terminal) 4 ················· ..Second terminal holding part (movable terminal holding part) 6... First terminal holding part (immobile terminal holding part) 7 ... Hole of resistive element 19... Protrusion for stopping extension 20... Protrusion for preventing removal 26... Elastic body for reducing load

Claims (6)

[Claims] 1. A non-conductive elastomer comprising: a pair of measuring terminals for measuring a change in electric resistance value; and an elongated conductive resistor having both ends connected to these terminals. An elongation sensing element characterized in that a conductivity-imparting material is dispersed and compounded in the elongation sensing element. 2. The pair of terminals are respectively fitted and connected to holes formed in the elongated conductive resistor, and an outer peripheral portion of each terminal is provided with a through hole pressed against an inner peripheral surface of the hole. The extension sensing element according to claim 1, wherein a projection for prevention is formed. 3. One of the pair of terminals is fixed to a first terminal holding portion, and the other terminal is slidable by the second terminal holding portion in a direction in which the elongated conductive resistor extends. 2. The extension sensing device according to claim 1, wherein the second terminal holding portion has a sliding holding surface along the outer peripheral shape of the other terminal having a non-circular cross section. element. 4. One of the pair of terminals is fixed to a first terminal holding portion, and the other terminal is slidable by the second terminal holding portion in a direction in which the elongated conductive resistor extends. Is formed on the outer peripheral portion of the other terminal, and the extension-stopping convex portion interferes with the second terminal holding portion in a state where the resistor is extended by a predetermined length. The extension sensing element according to claim 1, wherein 5. One of the pair of terminals is fixed to a first terminal holding portion, and the other terminal is slidable in a direction in which the elongated conductive resistor extends by a second terminal holding portion. The elongated conductive resistor is covered with an electrically insulating tubular cover material having an inner diameter larger than the maximum diameter of the resistor, and the first terminal holding portion is provided at one end of the tubular cover material. The extension sensing element according to claim 1, wherein the second terminal holding portion is provided on the other end side. 6. One of the pair of terminals is fixed to a first terminal holding portion, and the other terminal is slidable in a direction in which the elongated conductive resistor extends by a second terminal holding portion. The elastic member for load reduction is interposed between the second terminal holding portion and the end of the elongated conductive resistor on the second terminal holding portion side. Extension sensing element.