JP2011249277A - Proximity switch and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a proximity switch capable of simplifying the layout work of a magnet, and downsizing the whole of the switch; and a method of manufacturing the same.SOLUTION: A neutral detection switch 120 constitutes a detecting portion 121 for detecting a projection 310 made from magnetic materials rotating around a predetermined center axis m1, and comprises a bias magnet 140 of a C-shaped cross section which forms a magnetic field changing according to a rotating position of the projection 310, and MR sensors 131, 132 detecting the changes of the magnetic field. The bias magnet 140 has a plurality of magnet elements 140a, 140b, and the plurality of the magnet elements 140a, 140b is integrated by a recessed portion 141 to which inner surfaces 141a, 141b oppose through a sensor mounting member 130 mounting the MR sensors 131, 132.

Description

  The present invention relates to a proximity switch that detects whether or not an object to be detected is approaching, and a manufacturing method thereof.

  As is well known, a vehicle equipped with a manual transmission is provided with a shift device that changes the gear stage of the transmission based on an operation of an operation lever by a driver.

  Conventionally, this type of shift device is known to include a neutral detection switch for detecting whether or not the operation position of the operation lever is a neutral position in order to execute various controls of the vehicle. (For example, refer to Patent Document 1).

  The neutral detection switch is formed by a package switch having a detection portion that faces the detected portion by rotation of the shaft by operating the operation lever to the neutral position, and a package that seals the detection portion with resin.

  The detection unit includes a magnet that forms a magnetic field that varies depending on the rotational position of the detected portion, and a pair of magnetic sensors that detect changes in the magnetic field caused by the magnet.

  The magnet is formed by a U-shaped magnet having a recess opening in three directions. The pair of magnetic sensors is formed by a package sensor which is arranged in parallel with each other on a sensor mounting substrate and is resin-sealed together with a part of the sensor mounting substrate. A part of the package sensor is accommodated in the recess of the magnet.

  The package has a threaded portion on the outer peripheral surface, and is attached to the case of the shift device (transmission) via the threaded portion, and is entirely formed of a cylindrical plastic.

  The shaft has a convex portion as a detected portion that protrudes toward the detection portion, and is formed by a magnetic member that rotates and moves by operation of an operation lever.

  In the neutral detection switch, when the convex portion is rotated by the operation of the operation lever, the magnetic field formed by the magnet changes due to a change in the distance between the detection portion and the convex portion. It is configured to detect whether or not the operation position is a neutral position.

  With the above configuration, when the operation position of the operation lever is the neutral position, the convex portion is positioned to face the neutral position of the detection unit, so that it is detected that the operation position of the operation lever is the neutral position.

  On the other hand, when the operation position of the operation lever is a position other than the neutral position, the convex portion is in a position that does not face the neutral position of the detection unit, so that it is detected that the operation position of the operation lever is not the neutral position.

  By the way, in order to manufacture the proximity switch described above, a part of a sensor mounting member on which a magnetic sensor is mounted in advance is insert-molded together with the magnetic sensor to form a package sensor, and then externally connected to the magnetic sensor via the sensor mounting member. Connect the lead for connection, and then insert a U-shaped magnet between the package sensor and the lead for external connection to accommodate a part of the package sensor in the recess, and then connect the lead for external connection. This is done by insert molding the leads together with the package sensor and magnet to form a package switch.

JP 2009-206058 A

  However, according to the conventional proximity switch, a magnet having a U-shaped cross section is inserted between the package sensor and the lead for external connection, and a part of the package sensor is accommodated in the recess, so that the magnet is placed at a predetermined position. Had been placed in. As a result, there has been a problem that the operation of arranging the magnet at a predetermined position requires two operations of an insertion operation and an accommodating operation, which complicates the magnet arrangement operation.

  Further, according to the conventional proximity switch, there is a problem that a large space is required as a space for inserting the magnet, and the entire switch is increased in size.

  Accordingly, an object of the present invention is to provide a proximity switch that can simplify the magnet placement operation and reduce the size of the entire apparatus, and a method of manufacturing the proximity switch.

  In order to achieve the above object, the present invention provides a proximity switch (1) to (3) and a manufacturing method thereof.

(1) A detection unit configured to detect a detection unit made of a magnetic material that rotates around a predetermined central axis, and a U-shaped magnet that forms a magnetic field that varies depending on the rotation position of the detection unit; The magnetic sensor includes a magnetic sensor for detecting a change in the magnetic field, and the magnet includes a plurality of magnet elements, and the plurality of magnet elements are integrated with a concave portion whose inner surface is opposed via a sensor mounting member for mounting the magnetic sensor. Proximity switch that is.

(2) In the proximity switch according to (1), the magnet has a region where the recess is formed as one pole, and a region opposite to the region where the recess is formed as the other pole. .

(3) In a method of manufacturing a proximity switch including a detection unit that detects a detection unit made of a magnetic material that rotates around a predetermined center axis, among a plurality of magnet materials that serve as magnets constituting the detection unit A switch body is formed by insert molding part of a magnet material on one side and a sensor mounting member on which a magnetic sensor that constitutes the detection unit together with the magnet is formed, and the other side member among the plurality of magnet materials A first step of forming a switch cap by insert molding, a second step of mounting the magnetic sensor on the sensor mounting member, and the one side member and the other side by assembling the switch cap to the switch body By integrating the side members, a U-shaped cross-section having a recess whose inner surface faces through the sensor mounting member Third step and the fourth step in the method of manufacturing the proximity switch with forming a U-shaped cross section of the magnet is subjected to magnetization treatment on the magnetic forming member that forms a magnet forming member.

  According to the present invention, it is possible to simplify the magnet placement work and reduce the size of the entire apparatus.

The perspective view which shows the shift apparatus of the vehicle by which the proximity switch which concerns on embodiment of this invention is mounted. Sectional drawing which shows the manual transmission of the vehicle by which the proximity switch which concerns on embodiment of this invention is mounted. The perspective view shown in order to demonstrate the proximity switch which concerns on embodiment of this invention. AA sectional drawing of FIG. (A) And (b) is the front view and side view shown in order to demonstrate the detection part of the proximity switch which concerns on embodiment of this invention. (A) shows a front view, and (b) shows a side view. The perspective view shown in order to demonstrate the magnet of the proximity switch which concerns on embodiment of this invention. (A) And (b) is a circuit diagram which shows the circuit structure of the circuit board in the proximity switch which concerns on embodiment of this invention. (A) shows one magnetic sensor, and (b) shows the other magnetic sensor. (A) And (b) is the front view which shows the rotation position of the to-be-detected part, and the state of a magnetic field when the operation lever is arrange | positioned in positions other than a neutral position in the proximity switch which concerns on embodiment of this invention. The side view shown typically. (A) shows a front view, and (b) shows a side view. (A) And (b) is the front view which shows the rotation position of the to-be-detected part when the operation lever is arrange | positioned in the neutral position in the proximity switch which concerns on embodiment of this invention, and the mode of a magnetic field typically FIG. (A) shows a front view, and (b) shows a side view. (A) And (b) is a front view which shows typically the change of direction of the magnetic vector applied to a pair of magnetic sensor in the proximity switch which concerns on embodiment of this invention. (A) shows one magnetic sensor, and (b) shows the other magnetic sensor. The graph which shows the relationship between the rotation angle of the to-be-detected part corresponding to the detection part of the proximity switch which concerns on embodiment of this invention, and the output voltage of a pair of magnetic sensor. (A) And (b) is a perspective view shown in order to demonstrate the 1st process in the manufacturing method of the proximity switch which concerns on embodiment of this invention. (A) shows one insert molding, and (b) shows the other insert molding. The perspective view shown in order to demonstrate the 2nd process in the manufacturing method of the proximity switch which concerns on embodiment of this invention. The perspective view shown in order to demonstrate the 3rd process in the manufacturing method of the proximity switch which concerns on embodiment of this invention. The flowchart shown in order to demonstrate the manufacturing method of the proximity switch which concerns on embodiment of this invention.

[Embodiment]
(Configuration of shift device)
FIG. 1 shows the entire shift device. As shown in FIG. 1, the shift device 200 includes a case panel 202 and an operation lever 210 and is disposed in an automobile (not shown).

  The case panel 202 is provided with a guide groove 201 for guiding the operation lever 210. The guide groove 201 is formed by grooves 201a to 201c extending in the y-axis direction and grooves 201d extending in the x-axis direction so as to connect the central portions of these grooves 201a to 201c.

  The operation lever 210 is movably inserted into the guide groove 201. Thus, when the operating lever 210 is operated to both ends of the grooves 201a to 201c by the driver, the gear positions of the manual transmission are “1st speed”, “2nd speed”, “3rd speed”, “4th speed”. , “5th speed” and “Reverse (R)”, respectively. If the operation lever 210 is operated to the groove 201d, the gear position of the manual transmission is in a state corresponding to “Neutral (N)”.

  The shift device 200 is provided with a neutral detection switch as a proximity switch for detecting whether or not the operation position of the operation lever 210 is a neutral position. Details of the neutral detection switch will be described later.

(Configuration of manual transmission)
Next, the manual transmission will be described with reference to FIG. FIG. 2 shows a manual transmission of an automobile. As shown in FIG. 2, the manual transmission 300 includes a select lever 301 and a shift lever 302 that operate in conjunction with movement of the operation lever 210 (shown in FIG. 1) in the x-axis direction and the y-axis direction, respectively. Installed in automobiles.

  The select lever 301 is rotatably supported via a bracket 303 on the outside of the transmission case 307 of the manual transmission 300. An operation lever 210 is connected to one end of the select lever 303 via a select cable 301a, and a shift lever 302 is connected to the other end.

  The shift lever 302 is connected to the operation lever 210 via the shift cable 302a and to the upper end of the change shaft 304.

  The change shaft 304 is supported by the transmission case 307 so as to be rotatable about the central axis m1 and movable along the central axis m1, and is entirely made of a magnetic material.

  As a result, if the driver operates the operation lever 210 in the x-axis direction, the select lever 301 rotates in the directions of arrows S10 and S11 in the drawing via the select cable 301a, and the change shaft 304 is centered along with this rotation. It moves in the direction of arrows S20 and S21 in the figure along the axis m1.

  Also, assuming that the operating lever 210 is operated in the y-axis direction by the driver, the shift lever 302 rotates in the directions of arrows T10 and T11 in the drawing via the shift cable 302a, and the change shaft 304 moves along the center axis along with this rotation. It rotates in the directions of arrows T20 and T21 around m1.

  Then, as the change shaft 304 moves in the directions of arrows S20 and S21 and rotates in the directions of arrows T20 and T21, an automobile synchronization device (not shown) is activated, and the gear stage of the manual transmission 300 is changed. .

  A convex portion 310 as a detected portion protruding from the outer peripheral surface is integrally provided at an intermediate portion in the axial direction of the change shaft 304. Thereby, the convex part 310 is integrated with the change shaft 304 and moves in the directions of arrows S20 and S21, and rotates in the directions of arrows T20 and T21.

  In the vicinity of the convex portion 310, a neutral detection switch 120 including a detecting unit 121 that detects the convex portion 310 is disposed.

(Overall configuration of neutral detection switch)
Next, the neutral detection switch 120 will be described with reference to FIGS. FIG. 3 shows the entire neutral detection switch. FIG. 4 shows a main part of the neutral detection switch. 5A and 5B show the detection unit. FIG. 6 shows a magnet. 7A and 7B show the circuit configuration of the circuit board. As shown in FIG. 3, the neutral detection switch 120 includes a package 122 that covers the detection unit 121 in addition to the detection unit 121 described above.

(Configuration of the detection unit 121)
The detection unit 121 includes a bias magnet 140 and a pair of magnetoresistive effect sensors (MR sensors) 131 and 132 and is sealed with a package 122 by resin.

  As shown in FIGS. 4, 5 (a), 5 (b), and 6, the bias magnet 140 is composed of a U-shaped magnet that forms a bias magnetic field that changes depending on the rotational position of the convex portion 310. The two inner surfaces 141a and 141b are opposed to each other through a sensor mounting member 130 with an external connection lead for mounting the MR sensors 131 and 132, and are disposed on the side of the change shaft 304. In the bias magnet 140, a region where the concave portion 141 is formed is an N pole, and a region opposite to the region where the concave portion 141 is formed is an S pole.

  The bias magnet 140 is formed by a magnet element 140a having an L-shaped cross section and a magnet element 140b having an I-shaped cross section. As the bias magnet 140, for example, a neodymium (Nd) rare earth magnet is used.

  The bias magnet 140 is formed after the L-shaped magnet material and the I-shaped magnet material (both not shown) are integrated to form a U-shaped magnet forming member (not shown). The magnet forming member is subjected to a magnetization process.

  In the present embodiment, the case where the bias magnet 140 having a U-shaped cross section is formed by the two magnet elements 140a and 140b has been described. However, the present invention is not limited to this, and the cross section is formed by three or more magnet elements. A U-shaped bias magnet may be formed.

  The recess 141 is formed from a pair of magnet ends interposed between the pair of MR sensors 131 and 132 to the center of the magnet.

  The sensor mounting member 130 is disposed at a position where the plate thickness direction is a direction along the tangential direction t at the intersection point P between the rotation locus c of the convex portion 310 and its normal line n.

  The pair of MR sensors 131 and 132 are parallel to each other along the direction of the central axis m1 in such a manner that each of them is symmetrical with respect to the normal line n. It is arranged closer. Thereby, even when the convex portion 310 rotates in the directions of arrows T20 and T21 as the change shaft 304 rotates in the directions of arrows T20 and T21 (shown in FIG. 2), the outputs of the pair of MR sensors 131 and 132 are output. The voltages Va and Vb (shown in FIG. 7) can be made equal.

  One MR sensor 131 includes four magnetoresistive elements 131a, 131b, 131c, and 131d as shown in FIG. 7A, and the other MR sensor 132 includes four magnetoresistive elements as shown in FIG. 7B. The circuits 132a, 132b, 132c, and 132d are formed on the sensor mounting member 130 as a full-bridge connected circuit.

  In the pair of MR sensors 131 and 132, the resistance values of the magnetoresistive elements 131a, 131b, 131c, 131d, 132a, 132b, 132c, and 132d change according to the direction of the magnetic vector of the bias magnetic field generated by the bias magnet 140. As a result, the output voltages Va and Vb change. A voltage Vcc is applied to the pair of MR sensors 131 and 132.

(Configuration of package 122)
As shown in FIGS. 3 and 4, the package 122 has a flange 122a for mounting a switch, and is attached to the transmission case 307 via the flange 122a. The package 122 is entirely normal to the rotation locus c of the convex portion 310. Is formed of a cylindrical member made of plastic. And the package 122 is comprised so that the detection part 121 may be resin-sealed.

  Further, the package 122 has a package end surface that faces the tip surface of the convex portion 310 when the convex portion 310 is located at the rotational position P2, that is, when the operation lever 210 (shown in FIG. 1) is operated to the neutral position. Placed in position.

  The flange 122a is provided with a screw insertion hole 122b having a center axis at a position eccentric from the center axis of the package 122. As a result, the neutral detection switch 120 is attached to the transmission case 307 of the manual transmission 300 (shown in FIG. 2) by inserting an attachment screw (not shown) through the screw insertion hole 122b and screwed to the transmission case 307. Done. For this reason, when the neutral detection switch 120 is attached to the transmission case 307 with an attachment screw, the neutral detection switch 120 is structured not to rotate with respect to the transmission case 307, so the outputs of the MR sensors 131 and 132 are the same output. These two outputs can be made redundant as a dual system.

(Operation of the neutral detection switch 120)
In the neutral detection switch 120 shown in the present embodiment, when the operation position of the operation lever 210 is the neutral position, the position where the convex portion 310 faces the neutral position of the detection unit 121 as in the conventional neutral detection switch. Therefore, it is detected that the operation position of the operation lever 210 is the neutral position.

  On the other hand, when the operation position of the operation lever 210 is a position other than the neutral position, the convex portion 310 is a position that does not oppose the neutral position of the detection unit 121, indicating that the operation position of the operation lever 210 is not the neutral position. Detected.

  Next, changes in the output voltages Va and Vb of the MR sensors 131 and 132 when the convex portion 310 is rotated from the state where it is positioned at the rotational position P3 toward the rotational position P2 will be described with reference to FIGS. I will explain. FIGS. 8A and 8B show the rotational position of the detected portion and the state of the magnetic field when the operation lever is arranged at a position other than the neutral position. FIGS. 9A and 9B show the rotational position of the detected portion and the state of the magnetic field when the operation lever is disposed at the neutral position. FIGS. 10A and 10B show changes in the direction of a magnetic vector applied to a pair of MR sensors. FIG. 11 shows the relationship between the rotation angle of the detected part corresponding to the detecting part and the output voltage of the pair of MR sensors.

  As shown in FIG. 8A, when the convex portion 310 is rotated from the state where the convex portion 310 is located at the rotational position P3 toward the rotational position P2, the bias magnetic field formed by the bias magnet 140 is attracted to the convex portion 310. To change. Specifically, as shown in FIG. 8B, the bias magnetic field is slightly drawn toward the convex portion 310 as a whole when the convex portion 310 reaches the rotational position P10 immediately before reaching the rotational position P2. To change. Magnetic vectors MV10 and MV20 applied to the MR sensors 131 and 132 are slightly directed toward the convex portion 310.

  Accordingly, the magnetic vectors MV10 and MV20 change in directions in which the angles θa and θb formed with the reference directions MV10b and MV20b are increased.

  Thereafter, it is assumed that the convex portion 310 has rotated to the rotational position P2. In this case, as shown in FIG. 9A, the bias magnetic field formed by the bias magnet 140 remains attracted to the convex portion 310 side, but the magnetic vectors MV10 and MV20 are rotated by the convex portion 310. Each changes slightly when compared with the time point when the position P10 is reached. Specifically, as shown in FIG. 9B, since the convex portion 310 comes closer to the MR sensors 131 and 132 than in the state shown in FIG. 8B, the magnetic vectors MV10 and MV20. Is directed in the direction attracted toward the convex portion 310, that is, the direction in which the angles θa and θb formed with the reference directions MV10b and MV20b are increased.

  Therefore, when the convex portion 310 changes from the rotational position P3 to the rotational position P2, as shown in FIGS. 10A and 10B, the angle θa between the magnetic vectors MV10 and MV20 and the reference directions MV10b and MV20b. , Θb change in the increasing direction.

  As shown in FIG. 11, when the convex portion 310 changes from the rotational position P3 to the rotational position P2, the output voltage Va of the MR sensor 131 gradually increases from a value Va31 that is smaller than the midpoint potential (Vcc / 2) of the circuit. It increases so that the value Va32 is slightly larger than the midpoint potential (Vcc / 2). On the other hand, the output voltage Vb of the MR sensor 132 changes so as to be a value Vb32 slightly smaller than the midpoint potential (Vcc / 2) of the circuit.

(Manufacturing method of the neutral detection switch 121)
Next, a method for manufacturing the neutral detection switch shown in the present embodiment will be described with reference to FIGS. 12A and 12B show the first step. FIG. 13 shows the third step. FIG. 14 shows the third step. FIG. 15 shows a flowchart.

  The manufacturing method of the neutral detection switch shown in this embodiment includes “the formation of the switch body and the switch cap (first step)”, “the mounting of the MR sensor (second step)”, “integration of the magnet material ( The third step) and the “magnet formation (fourth step)” are performed sequentially, so these steps are performed sequentially.

"Formation of switch body and switch cap"
First, as shown in FIG. 12A, a magnet material 140c having an L-shaped cross section as a magnet material on one side among a plurality of magnet materials (two pieces in the embodiment) to be the bias magnet 140, and an MR sensor The switch body A having the package 122 with the flange 122a is formed by insert-molding a part of the sensor mounting member 130 on which 131 and 132 are mounted.

  Next, as shown in FIG. 12B, the switch cap B is formed by insert-molding a magnet material 140d having an I-shaped cross section as the other magnet material among the plurality of magnet materials.

  In this way, the switch body A and the switch cap B can be formed (step S1 in FIG. 15).

"Mounting MR sensor"
As shown in FIG. 13, the MR sensors 130 and 132 are mounted on the mounting surface of the sensor mounting member 130 (step S2 in FIG. 15).

"Integration of magnet materials"
As shown in FIG. 14, the switch cap B is assembled to the switch body A to integrate the magnet materials 140c and 140d (step S3 in FIG. 15), whereby the inner surfaces 141a and 141b (FIG. 5) are interposed via the sensor mounting member 130. The magnet forming member C having the concave portions 141 facing each other is formed. The assembly of the switch cap B to the switch body A is performed, for example, by fusing the package resin forming the switch body A and the switch cap B, respectively.

"Formation of magnet"
Magnet forming member C is magnetized to form U-shaped magnet 140 (shown in FIG. 6) having L-shaped magnet element 140a and I-shaped magnet element 140b (FIG. 15). Step S4). The magnetizing process for the magnet forming member C is performed by, for example, a static magnetic field using an electromagnet. In this case, in the magnet 140, the region where the concave portion 141 is formed is an N pole, and the region opposite to the region where the concave portion 141 is formed is an S pole.

[Effect of the embodiment]
According to the embodiment described above, the following effects can be obtained.

(1) Since the magnet elements 140a and 140b can be integrated with the concave portion 141 facing the inner surfaces 141a and 141b through the sensor mounting member 130 and the magnet 140 can be disposed at a predetermined position, the magnet 140 is positioned at a predetermined position. The two operations of the insertion operation and the housing operation that are conventionally required for the placement work are not necessary, and the placement work in the magnet 140 can be simplified.

(2) A sensor mounting surface on which the MR sensors 131 and 132 are mounted can be secured when the switch body A is formed, and a conventionally required package for resin-sealing the MR sensors 131 and 132 is not necessary.

(3) A large space on the opposite side of the magnet 140 from the recess forming side is not required as in the prior art, and the entire apparatus can be downsized.

(4) Since the neutral detection switch 120 has a structure that does not rotate with respect to the transmission case 307, the outputs of the MR sensors 131 and 132 can be made the same, and both these outputs can be made redundant so as to have redundancy. . Thus, in order to provide redundancy, a plurality of switches are not required, and the number of parts can be reduced to reduce the cost and to reduce the size and weight of the entire switch.

  Although the proximity switch and the manufacturing method thereof according to the present invention have been described based on the above embodiment, the present invention is not limited to the above embodiment, and various modes can be used without departing from the scope of the present invention. For example, the following modifications are possible.

(1) In the above embodiment, in the bias magnet 140, the region where the concave portion 141 is formed is the N pole, and the region opposite to the region where the concave portion 141 is formed is the S pole. The present invention is not limited to this, and the region where the recess is formed may be the S pole, and the region opposite to the region where the recess is formed may be the N pole.

(2) In the above embodiment, the switch body A is formed and then the switch cap B is formed to manufacture the neutral detection switch 120. However, the present invention is not limited to this, and the switch cap is formed. After that, a neutral detection switch may be manufactured by forming a switch body.

(3) In the above embodiment, the case where the proximity switch is applied to the vehicle shift device as the neutral detection switch 120 has been described. However, the present invention is not limited to this, and various types such as turning on and off the headlight of the vehicle, for example. The present invention is also applicable to a lever switch device that operates switching of in-vehicle devices.

  DESCRIPTION OF SYMBOLS 120 ... Neutral detection switch, 121 ... Detection part, 122 ... Package, 122a ... Flange, 122b ... Screw insertion hole, 130 ... Sensor mounting member, 131 ... MR sensor, 131a, 131b, 131c, 131d ... Magnetoresistive element, 132 ... MR sensor, 132a, 132b, 132c, 132d ... magnetoresistive element, 140 ... bias magnet, 140a, 140b ... magnet element, 140c, 140d ... magnet material, 141 ... recess, 141a, 141b ... inner surface, 200 ... shift device, 201 Guide groove, 201a to 201d ... Groove, 202 ... Case panel, 210 ... Operating lever, 300 ... Manual transmission, 301 ... Select lever, 301a ... Select cable, 302 ... Shift lever, 302a ... Shift cable, 303 ... Bracket, 04 ... change shaft, 307 ... transmission case 310 ... protrusion, A ... switch body, B ... switch cap, C ... magnet forming member

Claims (3)

A detection unit configured to detect a detection unit made of a magnetic material that rotates around a predetermined center axis, a U-shaped magnet that forms a magnetic field that changes according to a rotation position of the detection unit, and the magnetic field Equipped with a magnetic sensor to detect changes,
The proximity switch in which the magnet has a plurality of magnet elements, and the plurality of magnet elements are integrated with a recess facing the inner surface via a sensor mounting member for mounting the magnetic sensor.   2. The proximity switch according to claim 1, wherein the magnet has a region where the recess is formed as one pole, and a region opposite to the region where the recess is formed as the other pole. In a method of manufacturing a proximity switch including a detection unit that detects a detection unit made of a magnetic material that rotates around a predetermined central axis,
The switch body is formed by insert-molding a part of a magnet material on one side of a plurality of magnet materials to be a magnet constituting the detection unit and a sensor mounting member on which the magnetic sensor constituting the detection unit is mounted together with the magnet. And forming a switch cap by insert-molding the other member of the plurality of magnet materials,
A second step of mounting the magnetic sensor on the sensor mounting member;
By attaching the switch cap to the switch body and integrating the one side member and the other side member, a magnet-forming member having a U-shaped cross section having a concave portion whose inner surface faces via the sensor mounting member. A third step of forming;
And a fourth step of forming the magnet having a U-shaped cross section by subjecting the magnet forming member to a magnetizing process.

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