JP2017009531A - Manufacturing method of pressure sensor and pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a pressure sensor and the pressure sensor capable of being manufactured without using a dummy wire.SOLUTION: A manufacturing method of a cylindrical pressure sensor 1 includes: an elastic insulator 2 having a hallow part 2a along a longitudinal direction; and a plurality of electrode wires 3 arranged in spiral shape along an inner peripheral surface of the hallow part 2a of the elastic insulator 2 and arranged so as not to come into contact with each other. The electrode wire 3 has a conductor 6 composed of a shape memory alloy, and the method includes: a step of making the conductor 6 store a spiral shape; a step of linearly drawing out the conductor 6; a step of forming the elastic insulator 2 around the electrode wire 3 including the conductor 6; and a step of restoring the conductor 6 into a previously stored spiral shape at the time or after the time of forming the elastic insulator 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pressure sensor manufacturing method and a pressure sensor.

  Conventionally, a cylindrical elastic insulator having a hollow portion along the longitudinal direction, and a plurality of elastic insulators arranged spirally along the inner peripheral surface of the hollow portion of the elastic insulator and not contacting each other There is known a pressure-sensitive sensor including an electrode wire.

  A pressure-sensitive sensor fulfills a switching function by contacting internal electrode wires when they are subjected to an external force and becoming a conductive state. For example, the pressure-sensitive sensor is used for pinching detection in a sliding door of a vehicle. Yes.

  In the conventional method of manufacturing a pressure-sensitive sensor, after the electrode wires and the dummy wires are more closely aligned, the surroundings are covered with an elastic insulator by extrusion molding, and then the dummy wires are drawn to form a hollow portion. It was general (see, for example, Patent Document 1).

Japanese Patent No. 3275767

  However, the conventional method for manufacturing a pressure-sensitive sensor requires a step of drawing a dummy wire after forming an elastic insulator, which takes time for manufacturing, and damages the inside of the pressure-sensitive sensor when the dummy wire is pulled out. There is a risk that. There was a problem. In addition, since the dummy line is discarded after manufacturing, there is a problem that it is wasteful.

  Therefore, an object of the present invention is to provide a pressure-sensitive sensor manufacturing method and a pressure-sensitive sensor that can be manufactured without using dummy wires.

  In order to solve the above-described problems, the present invention provides a cylindrical elastic insulator having a hollow portion along the longitudinal direction, and a spiral arrangement along the inner peripheral surface of the hollow portion of the elastic insulator. And a plurality of electrode wires arranged so as not to contact each other, the electrode wire having a conductor made of a shape memory alloy, and spiraling to the conductor A step of memorizing a shape, a step of extending the conductor in a straight line, a step of forming the elastic insulator around the electrode wire including the conductor, and at or after the formation of the elastic insulator, And a step of returning the conductor to a spiral shape stored in advance.

  Further, in order to solve the above problems, the present invention provides a cylindrical elastic insulator having a hollow portion along the longitudinal direction, and a spiral shape along the inner peripheral surface of the hollow portion of the elastic insulator. And a plurality of electrode wires arranged so as not to contact each other, wherein the electrode wire has a conductor made of a shape memory alloy, and the conductor is a spiral A pressure-sensitive sensor stored in a shape is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method and pressure sensor of a pressure sensor which can be manufactured without using a dummy line can be provided.

It is a figure which shows the pressure sensor manufactured with the manufacturing method of the pressure sensor which concerns on one embodiment of this invention, (a) is a figure which shows the state of an electrode wire typically, (b) is the 1B-1B. It is line sectional drawing. (A)-(c) is a figure explaining the manufacturing method of the pressure-sensitive sensor which concerns on this Embodiment. It is a figure explaining the manufacturing method of the pressure-sensitive sensor which concerns on one modification of this invention.

[Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  1A and 1B are diagrams showing a pressure-sensitive sensor manufactured by the method of manufacturing a pressure-sensitive sensor according to the present embodiment, in which FIG. 1A is a diagram schematically showing the state of an electrode wire, and FIG. It is a 1B line sectional view.

  As shown in FIGS. 1A and 1B, a pressure-sensitive sensor 1 includes a cylindrical elastic insulator 2 having a hollow portion 2a along the longitudinal direction, and an inner periphery of the hollow portion 2a of the elastic insulator 2. And a plurality of electrode wires 3 arranged in a spiral shape along the surface and arranged so as not to contact each other.

  Here, the elastic insulator 2 is formed in a cylindrical shape, and the hollow portion 2a is formed in a circular shape in a sectional view, but the shape of the elastic insulator 2 and the hollow portion 2a is not limited to this.

  In the present embodiment, the elastic insulator 2 includes an inner layer 4 facing the hollow portion 2 a and an outer layer 5 formed around the inner layer 4. Although details will be described later, in the manufacturing method of the pressure-sensitive sensor 1 according to the present embodiment, since irregularities are easily formed on the outer surface of the inner layer 4 at the time of manufacturing, the outer surface of the pressure-sensitive sensor 1 is made flat to improve the appearance. The outer layer 5 is formed. Here, although the cross-sectional shape of the outer layer 5 is circular, the outer layer 5 may be formed in a D shape in a cross-sectional view so that the pressure-sensitive sensor 1 can be easily fixed to a fixed object. Moreover, the inner layer 4 and the outer layer 5 may be comprised with the same material, and may be comprised with a different material.

  The electrode wire 3 is formed by coating a conductive rubber 7 around the conductor 6. In the present embodiment, the case where two electrode wires 3 are used will be described, but the number of electrode wires 3 may be three or more. The two electrode wires 3 are arranged so as to face each other with the hollow portion 2a interposed therebetween (with the center in the sectional view of the pressure-sensitive sensor 1 interposed). The conductive rubber 7 is made of, for example, a rubber material containing carbon black.

  In the pressure-sensitive sensor 1 according to the present embodiment, the conductor 6 is made of a shape memory alloy and is stored in a spiral shape. That is, even when the conductor 6 is deformed at a temperature lower than the transformation point of the shape memory alloy constituting the conductor 6 (deformed to such an extent that the crystal structure does not change), when the conductor 6 is heated to a temperature higher than the transformation point, The shape is stored in advance so as to obtain the shape.

  Next, a manufacturing method of the pressure sensor 1 will be described.

  As shown in FIG. 2A, first, the conductor 6 is stored with a spiral shape. At this time, for example, in a state where the conductor 6 is deformed in a spiral shape, a temperature higher than the transformation point of the shape memory alloy constituting the conductor 6 (temperature at which the crystal structure changes) is applied to the conductor 6. 6 can store a spiral shape. At this time, by making the spiral shape memorized in the conductor 6 slightly larger than the diameter of the hollow part 2a to be formed later (the diameter of the die 21 described later), the conductor 6 is detached from the hollow part 2a. Can be suppressed.

  Then, as shown in FIG.2 (b), the conductor 6 is extended linearly. This step is performed at a temperature below the transformation point of the shape memory alloy constituting the conductor 6.

  Thereafter, the conductor 6 is covered with the conductive rubber 7 to form the electrode wire 3. At this time, the temperature at which the conductive rubber 7 is coated is set to a temperature lower than the transformation point of the shape memory alloy constituting the conductor 6 so that the conductor 6 does not return to a spiral shape when the conductive rubber 7 is coated. The conductive rubber 7 is preferably crosslinked in advance by electron beam irradiation or the like.

  Then, as shown in FIG. The inner layer 4 of the elastic insulator 2 is formed around the electrode wire 3 by extrusion molding. At this time, a cylindrical mold 21 is used, and two electrode wires 3 are introduced along the axial direction of the mold 21 along the outer peripheral surface of the mold 21, and the inner layer 4 is formed around the mold 21. The hollow portion 2a can be formed by introducing the resin constituting the inner layer 4 and separating the resin constituting the inner layer 4 from the mold 21 in a state where the resin constituting the inner layer 4 is hardened to some extent.

  In the present embodiment, when the inner layer 4 of the elastic insulator 2 is formed, the conductor 6 is returned to a spiral shape stored in advance by heat during extrusion of the inner layer 4. The temperature at the time of extrusion molding of the inner layer 4 is set to a temperature equal to or higher than the transformation point of the shape memory alloy constituting the conductor 6.

  As a result, the conductor 6 returns to a spiral shape when it is detached from the mold 21 and is arranged in a spiral shape along the inner wall of the hollow portion 2a. In order to prevent the two electrode wires 3 from coming into contact with each other when the conductor 6 returns to a spiral shape, both electrode wires 3 are in a phase-matched state in consideration of the shape when returning to a spiral shape. Is introduced into the mold 21. At this time, in order to easily adjust the phases of the two electrode lines 3, a marker representing the shape when the two electrode lines 3 return to a spiral shape may be attached in advance. Further, by introducing the conductor 6 into the mold 21 while rotating it, the direction in which the conductor 6 bends when the mold 21 is released may be kept constant.

  In the present embodiment, since the inner layer 4 is formed while returning the electrode wire 3 to a spiral shape, the inner layer 4 is pushed outward by the electrode wire 3, and irregularities are easily formed on the outer surface of the inner layer 4. Therefore, an outer layer 5 is further formed around the inner layer 4 in order to make the outer surface of the pressure-sensitive sensor 1 flat and improve the appearance.

  After the inner layer 4 is formed, when the outer layer 5 is coated on the outer periphery of the inner layer 4 by extrusion molding, the resin constituting the outer layer 5 enters into the irregularities formed on the outer surface of the inner layer 4, thereby causing the inner layer 4 and the outer layer 5 to be displaced. Is suppressed. After the outer layer 5 is formed, the elastic insulator 2 is crosslinked with high-pressure steam or the like.

  In addition, as resin which comprises the outer layer 5, the temperature at the time of extrusion molding becomes below the temperature at the time of extrusion molding of the inner layer 4, and it suppresses that the inner layer 4 melt | dissolves at the time of the outer layer 5 extrusion molding. It is desirable. Thus, the pressure sensitive sensor 1 of FIG. 1 is obtained.

Thus, in the manufacturing method of the pressure-sensitive sensor 1 according to the present embodiment,
(1) The temperature at which the conductive rubber 7 is coated is a temperature lower than the transformation point of the shape memory alloy constituting the conductor 6,
(2) The temperature at the time of extrusion molding of the inner layer 4 is a temperature equal to or higher than the transformation point of the shape memory alloy constituting the conductor 6, and
(3) The temperature at the time of extrusion molding of the outer layer 5 is not more than the temperature at the time of extrusion molding of the inner layer 4,
Is required.

  For example, when a titanium-nickel-copper alloy (Ti: Ni: Cu = 50: 20: 30 (mass ratio)) is used as the shape memory alloy constituting the conductor 6, the transformation point of the alloy is about 80 ° C. (transformation start). Since the temperature is 80 ° C. and the reverse transformation start temperature is 85 ° C., urethane is used as the resin constituting the inner layer 4 and the outer layer 5, the temperature during extrusion molding of the inner layer 4 is 200 ° C., and during the extrusion molding of the outer layer 5. The temperature can be 190 ° C.

  In the present embodiment, the conductor 6 is memorized in a spiral shape, and after the conductor 6 is stretched linearly, the conductor 6 is covered with the conductive rubber 7 to form the electrode wire 3. Instead, after the electrode wire 3 is formed, the conductor 6 may store a spiral shape.

  In this case, after forming the electrode wire 3 by covering the conductor 6 with the conductive rubber 7, the electrode wire 3 is deformed into a spiral shape, and the temperature (crystal structure) is equal to or higher than the transformation point of the shape memory alloy constituting the conductor 6. The temperature is changed so that the spiral shape is stored in the conductor 6, and then the electrode wire 3 is linearly extended to form the elastic insulator 2. In this case, it is possible to use the conductive rubber 7 having a coating temperature equal to or higher than the transformation point of the shape memory alloy constituting the conductor 6. However, since it is necessary to store the spiral shape in the conductor 6 by applying a temperature equal to or higher than the transformation point of the shape memory alloy constituting the conductor 6 to the electrode wire 3 after the conductive rubber 7 is coated. It is necessary to use a rubber material that does not deteriorate due to the heat of the conductive rubber 7.

  Moreover, in this Embodiment, although the case where the conductor 6 was returned to the spiral shape memorized in advance by the heat at the time of extrusion molding of the inner layer 4 was described, not limited to this, after the inner layer 4 is extruded, You may make it return the conductor 6 to a helical shape.

  Specifically, as shown in FIG. 3, the inner layer 4 is extruded by setting the temperature during the extrusion of the inner layer 4 to a temperature lower than the transformation point of the shape memory alloy constituting the conductor 6, and then high-pressure steam or the like. To crosslink the inner layer 4. At this time, the electrode wire 3 returns to a spiral shape and remains in a straight state.

  Thereafter, by applying a temperature equal to or higher than the transformation point of the shape memory alloy constituting the conductor 6, the electrode wire 3 is formed in a spiral shape, and the outer layer 5 is formed around the inner layer 4 by extrusion molding. 1 is obtained. In addition, after forming the outer layer 5, you may make it return the electrode wire 3 to a helical shape, However, In this case, when the electrode wire 3 returns to a spiral shape, an unevenness | corrugation arises in the surface of the outer layer 5, and an external appearance deteriorates. It is possible that After the electrode wire 3 is returned to the spiral shape, the outer layer 5 is formed, whereby the appearance can be improved and the outer layer 5 enters the irregularities formed on the outer surface of the inner layer 4. 5 can be firmly fixed, and the inner layer 4 and the outer layer 5 can be prevented from shifting.

(Operation and effect of the embodiment)
As described above, in the method of manufacturing the pressure-sensitive sensor 1 according to the present embodiment, the electrode wire 3 includes the conductor 6 made of a shape memory alloy, and the conductor 6 stores a spiral shape; A step of extending the conductor 6 in a straight line, a step of forming the elastic insulator 2 around the electrode wire 3 including the conductor 6, and a spiral shape in which the conductor 6 is stored in advance during or after the formation of the elastic insulator 2 And a step of returning to the shape.

  As a result, the pressure-sensitive sensor 1 can be manufactured without using a dummy line as in the prior art. Therefore, it becomes possible to omit the process of removing the dummy wire, and the pressure-sensitive sensor 1 can be easily manufactured. In addition, since dummy lines that are discarded after manufacturing are not used, there is little waste and manufacturing costs can be reduced.

(Summary of embodiment)
Next, the technical idea grasped from the embodiment described above will be described with reference to the reference numerals in the embodiment. However, the reference numerals and the like in the following description are not intended to limit the constituent elements in the claims to the members and the like specifically shown in the embodiments.

[1] A cylindrical elastic insulator (2) having a hollow portion (2a) along the longitudinal direction, and spirally along the inner peripheral surface of the hollow portion (2a) of the elastic insulator (2) And a plurality of electrode wires (3) arranged so as not to contact each other, wherein the electrode wire (3) is made of a shape memory alloy. A conductor (6) having a spiral shape stored in the conductor (6), a step of linearly extending the conductor (6), and the electrode wire (3) including the conductor (6) ) Forming the elastic insulator (2) around the periphery, and returning the conductor (6) to a spiral shape stored in advance during or after the formation of the elastic insulator (2); A method for manufacturing a pressure-sensitive sensor (1).

[2] The elastic insulator (2) is formed by extrusion molding around the electrode wire (3), and the conductor (6) is returned to a spiral shape stored in advance by heat during the extrusion molding. The manufacturing method of the pressure sensitive sensor (1) as described in [1].

[3] After the conductive wire (7) is coated around the conductor (6) to form the electrode wire (3), a spiral shape is stored in the conductor (6). [1 ] Or the manufacturing method of the pressure sensor (1) according to [2].

[4] The spiral shape is stored in the conductor (6), and the conductor (6) is linearly stretched, and then the conductive rubber (7) is coated around the conductor (6). The method for manufacturing a pressure-sensitive sensor (1) according to [1] or [2], wherein the electrode wire (3) is formed.

[5] A cylindrical elastic insulator (2) having a hollow portion (2a) along the longitudinal direction, and spirally along the inner peripheral surface of the hollow portion (2a) of the elastic insulator (2) And a plurality of electrode wires (3) arranged so as not to contact each other, wherein the electrode wire (3) is a conductor made of a shape memory alloy ( 6), and the conductor (6) is memorized in a spiral shape.

  While the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the claims. In addition, it should be noted that not all the combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

  The present invention can be appropriately modified and implemented without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the case where the elastic insulator 2 includes the inner layer 4 and the outer layer 5 has been described, but the outer layer 5 can be omitted without being limited thereto. That is, the elastic insulator 2 may be composed of only one inner layer 4. In this case, it is possible to suppress deterioration of the appearance by forming the inner layer 4 thicker.

DESCRIPTION OF SYMBOLS 1 ... Pressure sensor 2 ... Elastic insulator 2a ... Hollow part 3 ... Electrode wire 4 ... Inner layer 5 ... Outer layer 6 ... Conductor 7 ... Conductive rubber

Claims (5)

A cylindrical elastic insulator having a hollow portion along the longitudinal direction;
A plurality of electrode wires arranged spirally along the inner peripheral surface of the hollow portion of the elastic insulator, and arranged not to contact each other;
A method of manufacturing a pressure sensitive sensor comprising:
The electrode wire has a conductor made of a shape memory alloy,
Storing a spiral shape in the conductor;
Extending the conductor in a straight line;
Forming the elastic insulator around the electrode wire including the conductor;
A step of returning the conductor to a spiral shape stored in advance during or after the formation of the elastic insulator,
A method for manufacturing a pressure-sensitive sensor. The elastic insulator was formed by extrusion molding around the electrode wire, and the conductor was returned to a spiral shape stored in advance by heat during the extrusion molding.
The manufacturing method of the pressure-sensitive sensor of Claim 1. After the conductive wire is coated around the conductor to form the electrode wire, the conductor is stored with a spiral shape,
A method for manufacturing the pressure-sensitive sensor according to claim 1. After the spiral shape is memorized in the conductor and the conductor is straightened, the electrode wire is formed by covering the conductor with a conductive conductive rubber.
A method for manufacturing the pressure-sensitive sensor according to claim 1. A cylindrical elastic insulator having a hollow portion along the longitudinal direction;
A plurality of electrode wires arranged spirally along the inner peripheral surface of the hollow portion of the elastic insulator, and arranged not to contact each other;
A pressure sensor comprising:
The electrode wire has a conductor made of a shape memory alloy,
The conductor is stored in a spiral shape,
Pressure sensitive sensor.

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