JP2018004414A - Stroke sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stroke sensor which can be easily built and has a high detection accuracy.SOLUTION: A stroke sensor A includes: a housing 2; a shaft 1 partially contained in the housing 2, the shaft reciprocating around the position of the original point by following a detection target body; a magnet 4 provided to the shaft 1; and a magnetism detection element 5 detecting a magnetic force from the magnet 4 which changes with the amount of movement of the shaft 1. The shaft 1 includes: metal shafts 11, 12; and guide parts 115, 123 for guiding the positional relation of the shafts 11, 12 while being in contact with the shafts before and after the shafts are engaged with each other to be connected together.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a stroke sensor.

  As a stroke sensor for detecting the amount of movement of a moving body such as a lever of an automobile or a motorcycle, there is one disclosed in Patent Document 1, for example. This stroke sensor is a stroke sensor that detects the amount of movement of a shaft that follows the movement of an object to be detected and the magnet provided on the shaft, and discloses a structure that houses components such as a shaft in a housing.

JP 2014-130035 A

In the stroke sensor described in Patent Document 1, since a non-magnetic material is used for the shaft, a part of the shaft is formed of synthetic resin. In this case, a process such as insert molding so as to include a magnet or the like is necessary and complicated.
In addition, when applied to a place where a large temperature change or vibration is applied, or when higher detection accuracy is required, it is necessary to apply a shaft made of a small metal material such as thermal deformation. Even in this case, a structure that can be easily assembled has been demanded.

  Therefore, an object of the present invention is to provide a stroke sensor that is easy to assemble and has high detection accuracy, paying attention to the above-mentioned problems.

In order to achieve the above object, a stroke sensor according to the present invention comprises:
A housing;
A shaft that is partly housed in the housing and reciprocates around the origin position following the object to be detected;
A magnetic detection element for detecting a magnetic force from a magnet that varies with the amount of movement of the shaft;
A stroke sensor comprising:
The shaft is composed of a plurality of shaft portions made of a metal material, and is provided with a guide portion that guides the positional relationship between the shaft portions before and after being connected to each other by screwing.

  Each of the plurality of shaft portions may be provided with a sliding portion that contacts the housing.

Also, an origin return means for returning the shaft to the origin position with respect to the housing is provided,
The origin returning means is characterized in that it is held by the shaft so as to be sandwiched by the connection of the plurality of shaft portions.

  According to the present invention, the stroke sensor can be easily assembled and has high detection accuracy.

The top view which shows embodiment of the stroke sensor of this invention Sectional drawing (VV sectional drawing of FIG. 1) of the stroke sensor of embodiment same as the above. The figure which shows the shaft before the assembly | attachment of embodiment same as the above. The figure which shows the shaft at the time of the assembly | attachment of embodiment same as the above. Sectional drawing which shows the 2nd case, shaft, and packing of embodiment same as the above. Sectional drawing which shows the stroke sensor before the assembly | attachment of the 1st case of embodiment same as the above.

  Hereinafter, as an embodiment of the present invention, a movable part mounted on a vehicle, for example, a movable part such as an operation lever, an accelerator pedal, a transmission, an intake throttle, etc. is used as a detected body, and a movement amount or an operation amount thereof is determined. An example applied to a stroke sensor to be detected will be described with reference to the accompanying drawings.

  As shown in FIGS. 1 and 2, the stroke sensor A of the present invention is a stroke sensor A that detects the amount of movement of the shaft 1 that reciprocates around the origin position following the detected object. A slidably supported housing 2 and an origin return means 3 provided between the shaft 1 and the housing 2 for detecting the amount of movement and returning the moved shaft 1 to the origin position. And a magnet 4 provided on the shaft 1 and a magnetic detection element 5 for detecting a movement amount from a change in the magnetic field accompanying the movement of the shaft 1 at a position facing the magnet 4 through the housing 2. The A packing 6 is assembled so that no foreign matter enters between the shaft 1 and the housing 2.

  The shaft 1 according to the present embodiment is a detection medium that follows the movement of the detection target. For example, the shaft 1 is connected to the detection target, transmits an external force, and reciprocates in the axial direction (longitudinal direction).

  As shown in FIGS. 3 and 4, the shaft 1 includes a first shaft (shaft portion) 11 and a second shaft (shaft portion) 12, and the first shaft 11 and the second shaft 12 are connected by screws. ing. As shown in FIG. 5, the shaft 1 is unitized with the origin returning means 3 and then assembled to the second case 22.

  The first shaft 11 is made of a nonmagnetic metal having a certain degree of rigidity, and is typically made of austenitic stainless steel (SUS; Steel Use Stainless). The first shaft 11 includes a connecting portion 111, a holding portion 112, a sliding portion 113, a housing portion 114, and a guide portion 115.

  The connecting portion 111 is on the end side of the guide portion 115 and has a thread formed on one end side of the first shaft 11, and can be connected to the second shaft 12.

  The holding portion 112 can slidably hold the origin returning means 3 including the piston 31 and the spring 32, and the origin is defined by the end surface 12a of the connected second shaft 12 and the end surface 112a facing the end surface 12a. The return means 3 is held so as to be sandwiched in the axial direction. The end faces 12a and 112a are in contact with a piston 31 of the origin returning means 3 described later, and transmit the pushing force to the piston 31 when the shaft 1 is pushed. As a result, a drag force is generated by the spring 32 via the piston 31, and the shaft 1 can be returned to the origin position.

  The sliding portion 113 is a portion that is formed on the other end side of the first shaft 11 (opposite side of the connecting portion 111), and that slides in contact with the inner wall surface in the housing (first case 21) 2. 2 is supported with high precision and is formed in a shape capable of preventing rotation rather than a cylinder. Thereby, the eccentricity of the shaft 1 due to the load of the spring 32 applied to the end faces 12a and 112a can be suppressed as much as possible. In addition, a groove 113a is formed in the sliding portion 113 so that the lubricant can be retained. In addition, as a non-rotating shape, a notch surface in which the side surface of the first shaft 11 is cut flat is formed to have a substantially D-shaped cross section, and the inner wall of the housing (first case 21) 2 is notched. It is sufficient to make it contact the surface. The stroke sensor A can prevent the magnet 4 from rotating together with the shaft 1 by this rotation prevention, so that the direction in which the magnet 4 and the magnetic detection element 5 face each other is kept constant, and the change in magnetic force can be accurately detected.

  The accommodating portion 114 is a concave portion formed on the end surface of the first shaft 11 on the other end side, and the magnet 4 is press-fitted and held. In this case, the magnet 4 is held in a shape that can be prevented from rotating so as not to be displaced, and is further firmly fixed using an adhesive.

  The guide portion 115 is formed of a cylindrical curved surface, is formed with a smooth surface similar to the surface on which the piston 31 of the holding portion 112 slides, and is screwed together by the connecting portion 111 as shown in FIG. By contacting the second shaft 12 before, the axial positions can be matched. Therefore, screwing by the connecting portion 111 is possible while maintaining the coaxial state.

  The second shaft 12 is connected to the first shaft 11, and a part thereof is accommodated in the housing (second case 22) 2. For example, a metal material is used for the second shaft 12. As with the first shaft 11, the second shaft 12 is preferably made of a non-magnetic material. However, since the distance from the magnet 4 and the magnetic detection element 5 is secured, a magnetic field can be used even with a soft magnetic material such as steel. The material has a low degree of influence, and it is possible to select a material as appropriate in light of cost and strength.

  The second shaft 12 includes a connecting part 121, a sliding part 122, and a guide part 123. The connecting part 121 is screwed and connected to the connecting part 111 of the first shaft 11 through which the origin returning means 3 is passed. At the time of connection, screw loosening is prevented between the connecting portions 111 and 121 with a reinforcing adhesive (for example, seal lock agent). The second shaft 12 includes a sliding portion 122 similar to the sliding portion 113 of the first shaft 11, and slides in contact with the inner wall of the housing (second case 22) 2. In addition, the sliding portion 122 includes a groove portion 122a for storing a lubricant, similarly to the groove portion 113a. In this case, the second shaft 12 is not subjected to rotation prevention with respect to the housing 2.

  The second shaft 12 is formed with a cylindrical inner wall curved surface, and a guide portion 123 having a smooth surface corresponding to the dimension of the guide portion 115 of the first shaft 11 is formed on the further end side of the connecting portion 121. The As shown in FIG. 4, the guide portion 123 is fitted in contact with the guide portion 115 before the coupling portions 111 and 121 are screwed together. Due to this contact state, the first shaft 11 and the second shaft 12 are coaxial, and while maintaining this state, the origin return means 4 is sandwiched between the end faces 12a and 112a, and at the same time, the connecting portions 111 and 121 are screwed together. Can be connected. Therefore, even if there is a repulsive force (elastic force) due to the spring 32, the screwing operation can be easily performed without being displaced.

  Further, since the guide portion 123 is provided at a position overlapping the sliding portion 122 on the inner wall side of the sliding portion 122, the first and second shafts 11 and 12 are pivotally supported at the same position, and the shaft 1 is divided. Even so, the axial accuracy can be increased. Moreover, since the sliding part 122 part of the shaft 1 is made solid and it becomes difficult to deform | transform, a highly accurate detection can be maintained.

  The housing 2 is provided with a first case 21 that accommodates the first shaft 11 while sliding, and a second case 22 that accommodates the second shaft 12 while sliding.

  The first case 21 is formed of a nonmagnetic material in a substantially cylindrical shape. For example, a metal material such as aluminum or stainless steel, or PBT (Poly Butylene Terephthalate) is used. As shown in FIG. 6, the first case 21 is formed in a cap shape, and is provided with a connecting means 211, a sliding surface 212, and an accommodating means (detection unit) 213.

  The connecting means 211 is formed when connecting to the second case 21, and the threaded portion 211 a that is threaded to be screwed together, and the screw portion 211 a is screwed into the first case 21. Before the contact, the abutting portion 211b that guides and contacts the second case 21 is formed. In this case, the screw part 211 a and the contact part 21 b are formed on the inner wall side of the first case 21.

  Since the first case 21 and the second case 22 are aligned with each other by the abutting portion 211b, the screw portion 211a can be screwed in from the correct direction, and assembling is easy. Become. Moreover, since the contact state is continued even after the first case 21 and the second case 22 are assembled, the rigidity of the housing 2 can be increased.

  In addition, since the screw portion 211a is arranged outside the contact portion 211b and external influence is difficult to reach the inner contact portion 211b, it prevents adhesion of foreign substances and corrosion and keeps the same axis. Can be maintained. Furthermore, this action can be enhanced by using a reinforcing adhesive (for example, a seal lock agent) at the time of connection.

  The sliding surface 212 is formed on the inner wall on the back side of the coupling means 211 in the housing space of the shaft 1, and supports the shaft 1 so as to be slidable against the sliding portion 113 formed on the side wall of the first shaft 11. . The sliding surface 212 is formed in a substantially D-shaped cross section that contacts the outer surface of the notch surface of the first shaft 11, and also prevents the shaft 1 from rotating. Therefore, the distance accuracy between the magnet 4 and the magnetic detection element 5 can be made constant, and the detection accuracy can be increased.

  The accommodating means 213 can hold the magnetic detection element 5 in the vicinity of the magnet 4. In this case, the accommodating means 213 uses the screw 213b in the concave accommodating means 213 by assembling the printed wiring board 213a mounted with the magnetic detection element 5 and externally connected via the cable C from the outside of the first case 21. Held. Further, the accommodating means 213 is provided with a filling member 213c for hermetically connecting the printed wiring board 213a and the cable C.

  Further, the first case 21 is provided with an end face 214 that determines the position of the shaft 1 in the axial direction, and the movement of the shaft 1 is restricted by contacting the piston 31.

  For example, a metal material is used for the second case 22. As with the first case 21, the second case 22 is preferably made of a non-magnetic material. However, since the distance from the magnet 4 and the magnetic detection element 5 is secured, a magnetic field can be used even with a soft magnetic material such as steel. The material has a low degree of influence, and it is possible to select a material as appropriate in light of cost and strength.

  The second case 22 is formed with connecting means 221 having a shape corresponding to the connecting means of the first case 21. In this case, as shown in FIG. 5, the connecting means 221 includes a screw part 221a and an abutting part 221b formed on the outer side of the second case 22 and a screw part 211a of the connecting means 211 of the first case 21, respectively. It is provided so as to correspond to the contact portion 211b.

  Further, the connecting means 221 is formed with a tapered surface 221c for guiding the contact portion 211b to a predetermined position where the contact portion 211b contacts the contact portion 221b of the second case 21 on the tip side of the surface facing the first case 21. ing. With the tapered surface 221c, contact of the contact portions 221b and 211b which are covered with the screw portion 211a of the first case 21 and cannot be seen can be facilitated. Therefore, when the screw portion 211a is formed closer to the opening end than the contact portion 211b, the first case 21 can be easily used even when the clearance between the contact portions 221b and 211b is extremely small. Since it can guide to the contact state (axis alignment) with the 2nd case 22, assembling property can be made easy.

  In addition, since the sliding part 113 of the 1st shaft 11 and the sliding surface 212 of the 1st case 21 contact | abut from the state shown in FIG. 6 to the assembly | attachment state shown in FIG. Without being conscious of the state, the housings 2 can be screwed together.

  The second case 22 has a sliding surface 222 and an end surface 223 formed in the same manner as the first case 21. The sliding surface 222 is formed on the inner wall of the cylindrical second case 22 and pivotally supports the shaft 1 so as to be slidable against the sliding portion 122 formed on the side wall of the second shaft 12. The end surface 223 restricts the movement of the shaft 1 by contacting the piston 31.

  The origin returning means 3 is composed of a pair of pistons 31 and 31 and a spring 32 that is mounted between the pistons 31 and 31 and biases them away from each other. For example, a metal material is used for the two pistons 31. The two pistons 31 are preferably made of a non-magnetic material. However, since the distance from the magnet 4 is ensured, even a soft magnetic material such as a steel material has a low influence on the magnetic field, and has durability and strength. It is possible to select materials appropriately in light of the comparison.

  The two pistons 31 are formed in a cylindrical shape with a bottom, and a mounting hole for mounting to the holding portion 112 of the first shaft 11 is formed in the center of the bottom portion. The two pistons 31 are opposed to each other with the bottom portion facing outward, and are slidably mounted on the holding portion 112 of the first shaft 11, and a spring 32 formed of a coil spring is interposed between the two pistons 31. 1 shaft 11 is mounted.

  The two pistons 31 are arranged between the end surfaces 214 and 223 by being formed by connecting the first case 21 and the second case 22. The two pistons 31 are provided so as to have a clearance with respect to the inner wall surface of the housing (second case 22) 2. With this clearance, the shaft 1 is assembled in the housing (second case 22) 2. Even if stress is applied to the shaft 1 due to workability or a large load applied after the vehicle is mounted, the two pistons 31 are less likely to contact the inner wall surface of the housing 2. It is possible to prevent factors that affect the operational feeling such as the inner wall surface being damaged.

  As the spring 32, a coil spring made of stainless steel, for example, a nonmagnetic metal such as SUS304WPB is preferably used. However, since the spring 32 has a distance from the magnet 4, even if it is a soft magnetic material (for example, SWB or SWC), a magnetic field is used. Therefore, the material may be appropriately selected in light of durability and strength. Moreover, since the two pistons 31 can be pressed against the end surfaces 214 and 223 and the end surfaces 112a and 12a by the spring 32 regardless of the position of the shaft 1, the clearance 2 with respect to the inner wall surface is provided. Even one piston 31 can be held without vibration. For this reason, a constant operational feeling can be provided for the stroke of the shaft 1. Moreover, the detection accuracy by the magnetic detection element 5 can be stabilized by preventing the vibration of the two pistons 31.

  As shown in FIG. 2, the two pistons 31 of the origin returning means 3 are separated from each other by the piston 31 a contacting the end surfaces 214 and 223 of the housing 2 and the end surfaces 112 a and 12 a of the shaft 1 at the origin position. Is regulated. The separation distance (interval) between the cylindrical portions of the two pistons 31 in this state (origin position) is the detection stroke of the shaft 1.

  In the origin return means 3, when the shaft 1 at the origin position is displaced so as to be pushed into the housing 2, the piston 31 moves to the end face 214 of the housing (first case 21) 2 and the end face of the shaft (second shaft 12). The cylindrical portion of the two pistons 31 moves against the spring 32 while moving away from the end surface 223 of the housing (second case 22) 2 and the end surface 112a of the shaft (first shaft 11) 1 while abutting against the spring 12a. It can move by the detection stroke until it hits. When the force for pushing the shaft 1 disappears, the shaft 1 is returned to the origin position by the spring force accumulated in the spring 32.

  Further, in the origin return means 3, when the shaft 1 at the origin position is displaced so as to be pulled out from the housing 2, the piston 31 is connected to the end surface 223 of the housing (second case 22) 2 and the shaft (first shaft). 11) while moving away from the end surface 214 of the housing (first case 21) 2 and the end surface 12 a of the shaft (second shaft 12) 1 while abutting against the end surface 112 a of 11) It is possible to move by the detection stroke until 31 cylindrical portions hit. When the force for pushing the shaft 1 disappears, the shaft 1 is returned to the origin position by the spring force accumulated in the spring 32. Note that a lubricant such as grease is applied to the outer peripheral surface of the piston housing portion in which the piston 31 is housed to ensure a long-term stable sliding with respect to the first shaft 11.

  The magnet 4 is composed of a rare earth magnet (for example, a magnet made of a material such as SmCo or NdFeB) formed in a quadrangular prism shape or a cylindrical shape. In this embodiment, the magnet 4 has a cylindrical shape using an SmCo sintered magnet, and two poles are magnetized in the axial direction (longitudinal direction) of the shaft 1. The magnet 4 is accommodated in the accommodating portion 114 of the first shaft 11 of the shaft 1 and fixed with an adhesive or the like.

  The magnet 4 provides a magnetic field to the magnetic detection element 5 facing the magnet 4 of the first case 21, and the direction (magnetic force) of the magnetic field applied to the magnetic detection element 5 by the displacement of the magnet 4 together with the shaft 1. As a result, the magnetic detection element 5 detects the amount of movement. The magnet 4 may be either a sintered magnet or a plastic magnet compressed or molded by mixing with plastic according to a manufacturing method. The sintered magnet has a stronger magnetic force, while the plastic magnet has characteristics such as higher mass productivity and higher crack resistance. Therefore, the sintered magnet may be appropriately selected according to use conditions and design requirements.

  The magnetic detection element 5 detects a displacement such as the amount of movement of the detected object. For example, the magnetic detection element 5 includes a Hall element and converts a change in magnetic force associated with the displacement such as the movement of the detected object into an electric signal. Output to the outside. For example, the magnetic detection element 5 is configured as a magnetic detection package by mounting a plurality of Hall elements on a circuit board.

  Here, the detection surface of the magnetic detection element 5 is arranged in a direction perpendicular to the magnetization direction of the magnet 4. The magnetic detection package including the magnetic detection element 5 is mounted on the surface of the printed wiring board 213a on the magnet 4 side, is stored in the storage means 213 of the housing 2 (first case 21), and is temporarily fixed with positioning pins or screws 213b. Thereafter, it is hermetically sealed with a potting agent (filling member). It can also be kept airtight with a packing or lid (not shown). By doing so, the gap with the magnet 4 is made as small as possible so that a change in the magnetic field can be detected with high accuracy.

  The power supply to the magnetic detection element 5 and the output to the outside are performed by a direct connector or a cord. The magnetic detection element 5 may be mounted on a wire frame or the like and configured as a magnetic detection package.

  The stroke detection using the magnetic detection element 5 described above detects a magnetic field in the vertical direction and a magnetic field in the horizontal direction with respect to the magnetic detection surface of the magnetic detection element 5 of a magnetic field formed by the magnet 4 by a plurality of Hall elements. The obtained vertical magnetic field and horizontal magnetic field are converted into angles by a trigonometric function (ATAN) in a processing circuit (for example, ASIC: Application Specific Integrated Circuit) and output as angle information. The output angle information and the movement amount (stroke) of the shaft 1 are proportional, and as a result, the movement amount of the shaft 1 can be detected.

  The output method from the magnetic detection package including the magnetic detection element 5 may be any method, and may be selected according to a control unit (ECU; Engine Control Unit) that uses the detection result ( For example, analog, PWM (Pulse Width Modulation), SENT (Single Edge Nibble Transmission), etc.).

  As the packing 6, a rubber packing with a cylindrical bellows that closes a gap between the shaft (second shaft 12) 1 and the housing (second case 22) 2 can be applied. The packing 6 is fixed so that the opening end of the packing 6 is sandwiched by fitting the opening at one end into the shaft 1 and press-fitting another metal member 61 into the housing 2 at the other end opening. Further, the inside of the housing 2 can be kept airtight while absorbing the displacement of the stroke amount by the middle bellows portion of the packing 6. In addition, since the 2nd shaft 12 rotates with respect to the 2nd case 22 by the screwing connection of the housings 2, the packing 6 is preferably assembled after this screwing connection.

  According to such a stroke sensor A, the housing 2, the shaft 1 that is partially housed in the housing 2 and reciprocates around the origin position following the detected body, the magnet 4 provided on the shaft 1, A stroke sensor A including a magnetic detection element 5 that detects a magnetic force from a magnet 4 that changes with the amount of movement of the shaft 1, and the shaft 1 includes a plurality of shafts 11 and 12 made of a metal material, Guide portions 115 and 123 are provided for guiding the positional relationship between the shafts 11 and 12 before and after being connected with each other by screwing.

  Therefore, it is easy to assemble the shafts 11 and 12 by the guides by the guide portions 115 and 123, and even after the assembly, the guide portions 115 and 123 provided in addition to the screwed portions (the coupling portions 111 and 121) Since the axial accuracy of the shaft 1 can be maintained high, the distance between the magnet 4 and the magnetic detection element 5 can be set as desired, resulting in a stroke sensor with high detection accuracy. Moreover, since the stroke sensor A can move the shaft 1 smoothly due to its high axial accuracy, it can prevent unnecessary wear and uncertain operation feeling. Further, since the shafts 11 and 12 can be held coaxially by the guide portions 115 and 123, a structure in which stress (load) is not easily applied to the connecting portions 111 and 121 other than the movement direction (axial direction) of the shaft 1 is obtained.

  Further, the shafts 11 and 12 are provided with the sliding portions 113 and 122 that come into contact with the housing, so that the shaft 1 is less likely to be displaced with respect to the housing 2 so that highly accurate stroke detection is possible.

  In addition, an origin return means 3 for returning the shaft 1 to the origin position with respect to the housing 2 is provided, and the origin return means 3 is held by the shaft 1 so as to be sandwiched by the connection between the plurality of shafts 11 and 12. Even in this case, the stroke sensor A can be easily assembled.

  Although the stroke sensor of the present invention has been described as an example in the configuration of the above-described embodiment, the present invention is not limited to this, and other configurations do not depart from the gist of the present invention. It goes without saying that various improvements and display changes can be made in the range. For example, regarding the screwing relationship between the housings 2, the relationship between the male screw and the female screw may be different from the embodiment described above.

  In addition, the structure in which the magnet 4 is held on the shaft 1 is shown. However, the magnet 4 is generated by applying a magnetic material to the moving shaft 1 and providing a magnet on the back side (opposite the detection surface) of the magnetic detection element. Further, it is possible to adopt a configuration for detecting a change in the bias magnetic field, and the amount of movement of the shaft 1 (the magnetic body) can be detected with high accuracy as in the above-described embodiment.

  The present invention relates to a stroke sensor, and is suitable as a stroke sensor that detects the amount of movement of a movable part mounted on a vehicle that vibrates due to traveling or the like.

A Stroke sensor 10 Shaft unit 1 Shaft 11 First shaft (shaft)
111 Connecting portion 112 Holding portion 112a End surface 113 Sliding portion 113a Groove portion 114 Housing portion 115 Guide portion 12 Second shaft (shaft portion)
12a end surface 121 connecting portion 122 sliding portion 122a groove portion 123 guide portion 2 housing 21 first case 211 connecting means 211a screw portion 211b abutting portion 212 sliding surface 213 housing means (detecting portion)
213a Printed circuit board 213b Screw 213c Filling member 214 End face 22 Second case 221 Connecting means 221a Screw part 221b Abutting part 221c Tapered face 222 Sliding face 223 End face 3 Origin return means 31 Piston 32 Spring 4 Magnet 5 Magnetic detection element 6 Packing

Claims (3)

A housing;
A shaft that is partly housed in the housing and reciprocates around the origin position following the object to be detected;
A magnetic detection element for detecting a magnetic force from a magnet that varies with the amount of movement of the shaft;
A stroke sensor comprising:
The shaft is composed of a plurality of shaft portions made of a metal material, and is provided with a guide portion that guides the positional relationship between the shaft portions before and after being connected by screwing together. Sensor. The stroke sensor according to claim 1, wherein each of the plurality of shaft portions is provided with a sliding portion that comes into contact with the housing. Origin return means for returning the shaft to the origin position relative to the housing,
2. The stroke sensor according to claim 1, wherein the origin returning means is held by the shaft so as to be sandwiched by the connection between the plurality of shaft portions.

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