JP2017125681A - Stroke sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stroke sensor with which it is possible to improve detection accuracy and give a desired feeling of operation.SOLUTION: Provided is a stroke sensor 1 for detecting the movement amount of a detection shaft 10 that reciprocates centering on an origin position O while tracking a test object, said sensor comprising a housing 20 for restricting the rotation of and slidably supporting the detection shaft 10 and a return to origin mechanism 30 provided between the detection shaft 10 and the housing 20 for detecting the movement amount and returning the detection shaft 10 to the origin position O after movement, the return to origin mechanism 30 being provided with a pair of pistons 31a, 31b and a spring 31c held between this pair of pistons 31a, 31b, the pair of pistons 31a, 31b having a space D1 between themselves and the opposing inner wall surface of the housing 20.SELECTED DRAWING: Figure 1

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, for example, there is one disclosed in Patent Document 1. The stroke sensor includes a shaft that follows the movement of the object to be detected, a housing in which the shaft is accommodated, a cap portion that is disposed so as to close one end portion of the housing and supports sliding of the shaft that passes therethrough, A detected object, comprising: a magnet provided at the other end; a magnetic detecting element provided in the housing for detecting a magnetic field change of the magnet; and an origin return mechanism for returning the shaft to the origin position after the shaft reciprocates. Is detected by a change in the magnetic field.

German Patent Application Publication No. 102010015036

  However, in the stroke sensor described in Patent Document 1, since the sliding portion that supports the shaft is configured by the inner peripheral surface of the cap portion that closes one end of the housing, the supporting width of the sliding portion is short with respect to the entire shaft length. In addition, since the magnet is arranged at the tip of the shaft, if the magnet mounting center and the shaft center are deviated, the detection gap between the magnet and the magnetic detection element fluctuates with the movement of the shaft, and the detection accuracy is increased. There is a problem of lowering.

  Further, if the center of the magnet and the center of the shaft are deviated, there is a problem that the shaft is strongly hit against a part of the sliding portion and local wear is likely to occur.

  In addition, when the number of sliding parts that serve as bearings for each component is increased, the shaft becomes a resistance force when moving, and there is a possibility that a desired operational feeling (a constant operational feeling) cannot be provided. Met.

  An object of the present invention is to provide a stroke sensor capable of improving the detection accuracy and giving a desired operational feeling by paying attention to the above-mentioned problems.

In order to achieve the above object, a stroke sensor according to the present invention comprises:
A stroke sensor that has a magnet and detects the amount of movement of the detection shaft that reciprocates around the origin position following the object to be detected by a magnetic detection element,
A housing that slidably supports the rotation of the detection shaft; and
An origin return mechanism provided between the detection shaft and the housing for detecting the amount of movement and returning the detection shaft after the movement to the origin position;
The origin return mechanism includes a pair of pistons and a spring sandwiched between the pair of pistons,
The pair of pistons is characterized in that a gap is provided between the opposing inner wall surfaces of the second housing.

A magnet provided on a side surface of the detection shaft;
A magnetic detection element provided on the housing so as to face the magnet and detecting the amount of movement from a change in magnetic field accompanying the movement of the detection shaft.

The detection shaft includes a first shaft made of a nonmagnetic material and a second shaft made of a magnetic material connected to the first shaft,
A first housing supporting the first shaft is made of a non-magnetic material;
It is characterized by that.

The second shaft, the second housing that houses the second shaft, and the origin return mechanism that is housed in the second housing are made of a metal material.
It is characterized by that.

  According to the present invention, it becomes a stroke sensor which can improve detection accuracy and can give a desired operational feeling.

It is (a) top view, (b) AA sectional view, (c) BB sectional view, and (d) CC sectional view showing one embodiment of a stroke sensor of the present invention. It is sectional drawing of the 1st shaft of one embodiment of this invention. It is sectional drawing of the 2nd shaft of one embodiment of this invention. It is sectional drawing of the 1st housing of one embodiment of this invention. It is sectional drawing of the 2nd housing of one embodiment of this invention. It is sectional drawing of the origin return mechanism of one embodiment of this invention.

  Hereinafter, a stroke sensor according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1, the stroke sensor 1 of the present invention is a stroke sensor 1 that detects the amount of movement of a detection shaft 10 that reciprocates around an origin position O following a detected object. A housing 20 that is slidably supported by restricting rotation, and an origin return mechanism that is provided between the detection shaft 10 and the housing 20 and detects the amount of movement and returns the detection shaft 10 to the origin position O. 30, and a magnet 40 provided on the side surface of the detection shaft 10, and a magnetic detection element 50 provided on the housing 20 so as to face the magnet 40 and detecting a movement amount from a change in the magnetic field accompanying the movement of the detection shaft 10. It is configured.

  The detection shaft 10 according to the present embodiment is a detection medium that follows the movement of the detection target. For example, the detection shaft 10 is connected to the detection target, transmits an external force, and reciprocates in the axial direction. As shown in FIGS. 1 to 3, the detection shaft 10 includes a first shaft 11 and a second shaft 12, and the first shaft 11 and the second shaft 12 are connected by screws.

  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 three large diameter portions 11a having different diameters, a medium diameter portion 11b, and a small diameter portion 11c.

  The small diameter portion 11c protrudes outward from the housing 20 (first housing 21), and is connected to the detected body. For example, a male screw 11d is formed, and is connected to the detected body with the screw and follows.

The large-diameter portion 11a and the middle-diameter portion 11b are disposed in the housing 20 (first housing 21), and their rotation is restricted by a sliding support portion 23 described later between the housing 20 (first housing 21). So that it can slide.

  The large-diameter portion 11a has a female screw portion 11e for connecting to the second shaft 12 on the end surface opposite to the small-diameter portion 11c. Further, a centering groove 11f for concentrating the position of the second shaft 12 and the centering state with the first shaft 11 is formed concentrically on the outer peripheral portion of the female screw portion 11e on the end surface of the large diameter portion 11a. is there. By forming the centering groove 11f, the center of the second shaft 12 and the center of the first shaft 11 are matched with high accuracy on the inner peripheral surface of the centering groove 11f, and the second shaft 12 is formed with an annular flat end surface. The tightening position can be held at a predetermined position for connection. Thereby, the eccentricity with respect to the 1st shaft 11 by the load of the spring 31c added to the 2nd shaft 12 mentioned later can be suppressed as much as possible.

  The end surface outside the centering groove 11f of the end surface of the large diameter portion 11a is a locking portion 11g of the piston 31a of the origin return mechanism 30 described later, and when the first shaft 11 is pushed in, the pushing force is applied to the piston 31a. introduce. Thereby, a drag force is generated by the spring 31c through the piston 31a, and the first shaft 11 can be returned to the origin position O.

  Further, the large diameter portion 11a is formed with a notch surface 11h having a flat side surface at the end opposite to the small diameter portion 11c, and has a substantially D-shaped cross section. The length of the notch surface 11h in the axial direction of the first shaft 11 is the same as or slightly longer than the detection stroke S. The rotation of the first shaft 11 is regulated by the notch surface 11h in cooperation with a sliding support portion 23 of the housing 20 (first housing 21) described later.

  The diameter middle portion 11b is formed with a radial magnet storage portion 11i on the side surface. A magnet 40 is housed in the magnet housing portion 11i and fixed with an adhesive or the like.

  The second shaft 12 is connected to the first shaft 11 to form the detection shaft 10 and is housed in the housing 20 (second housing 22). For example, a metal material is used for the second shaft 12. As with the first shaft 11, the second shaft 12 is preferably a non-magnetic material. However, since the distance from the magnet 40 is ensured, even if it is a soft magnetic material such as steel, the degree of influence on the magnetic field is small. It is low, and it is possible to select a material as appropriate in light of cost and strength.

  The second shaft 12 includes a large-diameter portion 12a having three different diameters, a mid-diameter portion 12b, and a small-diameter portion 12c. The small diameter portion 12c is formed with a male screw 12d, and a step portion 12e is formed between the male screw 12d and the diameter middle portion 12b. Thereby, the second shaft 12 and the first shaft 11 are connected by the male screw portion 12d and the female screw portion 11e of the first shaft 11, and the stepped portion 12e is tightened so as to be fitted in the centering groove 11f of the first shaft 11. Thus, they are connected in a centered state and at a predetermined axial position. When connecting, screws are prevented from loosening with a reinforcing adhesive (for example, sealock agent).

  The diameter middle portion 12b is formed in a cylindrical shape having a predetermined axial length, and is mounted with pistons 31a and 31b and a spring 31c of an origin return mechanism 30 described later.

  The large diameter portion 12a constitutes a locking portion 12f of a piston 31b of the origin return mechanism 30 described later, and makes a pair with the locking portion 11g of the piston 31a of the first shaft 11. The large-diameter portion 12a has, for example, a hexagonal shape around the outside, and can be rotated with a tool such as a wrench when connected to the first shaft 11.

  As shown in FIGS. 1, 4, and 5, the housing 20 is connected to the first housing 21 in which the first shaft 11 is mainly accommodated, and the second shaft 12 is mainly accommodated in the first housing 21. 2 housings 22.

  The first housing 21 is made of a non-magnetic material and has a substantially cylindrical shape. For example, a metal material such as aluminum or stainless steel, or a synthetic resin material such as PBT (Poly Butylene Terephthalate) or PPS (Poly Phenylene Sulfide) is used. Used. A large diameter hole portion 21a, a diameter medium hole portion 21b, and a small diameter hole portion 21c are continuously formed in the inner peripheral portion of the first housing 21, and the medium diameter hole portion 21b and the small diameter hole portion 21c A sliding support portion 23 of the first shaft 11 is configured.

  In the large-diameter hole portion 21a, a female screw portion 21d is formed at an intermediate portion of the inner peripheral surface, and the second housing 22 is connected by a screw. A circumferential surface 21e and an end surface 21f formed on the distal end side (diameter middle hole portion 21b side) of the female screw portion 21d are fitted into the second housing 22 in the large-diameter hole portion 21a, so that the centering and axial connection positions are achieved. Set. Further, the end surface 21f of the large-diameter hole portion 21a serves as a contact surface of a piston 31a of the origin return mechanism 30 described later.

  As shown in FIGS. 1 and 4, the inner diameter hole portion 21 b is formed in a substantially D-shaped cross section that comes into contact with the outer surface of the notch surface 11 h of the large-diameter portion 11 a of the first shaft 11, and extends in the axial direction. Is formed to have a sufficient axial length even if the first shaft 11 moves by the detection stroke S of the first shaft 11.

  The small-diameter hole portion 21c is formed to have an inner diameter with which the middle diameter portion 12b of the first shaft 11 can slide. Thereby, the rotation of the first shaft 11 around the central axis is restricted by the substantially D shape and the small diameter hole portion 21c of the inner diameter hole portion 21b constituting the sliding support portion 23 of the housing 20, and in the axial direction. The sliding for the detection stroke S is supported with high accuracy. Accordingly, the first shaft 11 is supported so as to be slidable with its overall length being restricted by the first housing 21.

  The first housing 21 is formed with a substrate housing portion 21g of the circuit board 51 on which the magnetic detection element 50 is mounted so as to face the magnet housing portion 11i of the first shaft 11. The substrate storage portion 21g is a rectangular recess having a bottom surface parallel to the notch surface 11h of the first shaft 11, and protrudes upward from the bottom surface to temporarily fix the positioning pins 21h of the circuit substrate 51 and the circuit substrate 51. An internal thread portion 21i for a screw is formed. By providing a positioning pin 21h and a female screw portion 21i for temporarily fixing the circuit board 51 in the board housing part 21g, the first magnetic detection element 50 mounted on the circuit board 51 is first with a gap as small as possible with respect to the magnet 40. It can be fixed to the housing 21 and the change of the magnetic field by the magnet 40 can be detected with high accuracy.

  The second housing 22 is connected to the first housing 21 to form the housing 20, and for example, a metal material is used. As with the first housing 21, the second housing 22 is preferably made of a non-magnetic material. However, since the distance from the magnet 40 is secured, the degree of influence on the magnetic field is not limited even if a soft magnetic material such as steel is used. It is low, and it is possible to select a material as appropriate in light of cost and strength.

  As shown in FIGS. 1 and 5, the second housing 22 is formed in a cylindrical shape having a substantially two-stage outer shape, and includes a large-diameter portion 22 a and a small-diameter portion 22 b.

  A male screw 22c is formed on the outer periphery of the intermediate portion of the large-diameter portion 22a, and the outer peripheral portion 22d and the front end surface 22e on the front end side from the male screw 22c are fitted to the peripheral surface 21e and the end surface 21f of the first housing 21. It is as. Thus, the male screw 22c of the second housing 22 and the female screw portion 21d of the first housing 21 can be connected in a centered state and tightened to a predetermined position in the axial direction.

  A cylindrical large hole portion 22f and a small diameter hole portion 22g are continuously formed on the inner peripheral side of the large diameter portion 22a, and the large diameter hole portion 22f connects the pistons 31a and 31b and the spring 31c of the origin return mechanism 30. It becomes the piston accommodating part 31d to accommodate. The small-diameter hole portion 22g serves as a storage space for the large-diameter portion 12a at the end of the second shaft 12. Further, a step surface 22h between the large-diameter hole portion 22f and the small-diameter hole portion 22g serves as a contact surface of a piston 31b of the origin return mechanism 30 described later.

The small-diameter portion 22b has a female screw portion 22i formed in the center portion from the outer end face, and is used for holding the detection target to be detected as a stroke.
Note that the second housing 22 is not limited to being formed of a metal material, and may be formed by insert molding a synthetic resin material using a screw portion as a metal material.

  As shown in FIGS. 1 and 6, the origin return mechanism 30 is mounted between a pair of pistons 31a and 31b and a spring 31c that is attached between the two pistons 31a and 31b and biases them away from each other. Composed.

  For example, a metal material is used for the two pistons 31a and 31b. The two pistons 31a and 31b are preferably made of a non-magnetic material. However, since the distance from the magnet 40 is ensured, even a soft magnetic material such as a steel material has a low influence on the magnetic field. It is possible to select a material as appropriate in light of the strength.

  The two pistons 31a and 31b are formed in a cylindrical shape with a bottom, and a mounting hole is formed in the center of the bottom portion for mounting on the middle diameter portion 12b of the second shaft 12. The two pistons 31a, 31b are opposed to each other with the bottom portion facing outward, and are slidably mounted on the diameter middle portion 12b of the second shaft 12, and a spring 31c configured by a coil spring is interposed between the two pistons 31a, 31b. Mounted on the second shaft 12.

  The two pistons 31a and 31b are disposed in a large-diameter hole portion 22f (piston housing portion 31d) of the second housing 22 formed by connecting the first housing 21 and the second housing 22. The two pistons 31a and 31b have a clearance D1 from the inner wall surface of the large-diameter hole portion 22f (piston housing portion 31d), and when the first shaft 11 and the second shaft 12 move by reducing the mutual contact area. The resistance is reduced. The gap D1 also facilitates the work when assembling the second shaft 12 with the two pistons 31a, 31b and the spring 31c attached to the large-diameter hole 22f. Further, in addition to the mutual diameter setting for sliding the second shaft 12 and the two pistons 31a and 31b, by providing the gap D1, the shaft 10 can be applied during assembly work or when a large load is applied after the vehicle is mounted. Is eccentric, the two pistons 31a and 31b are difficult to contact the inner wall surface of the large-diameter hole portion 22f (piston housing portion 31d), so that the spring 31c, the two pistons 31a and 31b, and the inner wall surface It can prevent factors that affect the operational feeling, such as being damaged.

  The spring 31c is formed of a coil spring made of stainless steel, for example, SUS304WPB. The spring 31c is preferably made of a non-magnetic metal such as stainless steel (for example, SUS304WPB). However, since the spring 31c has a distance from the magnet 40, 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 31a and 31b can be pressed against the end surface 21f and the stepped surface 22h by the spring 31c regardless of the position of the shaft 10, the two pistons having a gap D1 with respect to the inner wall surface are provided. Even the pistons 31a and 31b can be held without vibration. For this reason, a constant operational feeling can be provided for the stroke of the shaft 10. Moreover, the detection accuracy by the magnetic detection element 50 can be stabilized by preventing the vibration of the two pistons 31a and 31b.

  As shown in FIG. 1, the two pistons 31 a and 31 b of the origin return mechanism 30 are configured such that, at the origin position O, the outer surface of the piston 31 a (the outer surface of the bottom of the bottomed cylinder) is the large-diameter hole portion 21 a of the first housing 21. The outer surface of the other piston 31b (the outer surface of the bottom of the bottomed cylinder) is in contact with the step surface 22h of the large-diameter hole portion 22f of the second housing 22, so that the separation distance is regulated. The The separation distance (interval) between the cylindrical portions of the two pistons 31a and 31b in this state (origin position O) is the detection stroke S of the detection shaft 10 (see FIG. 6).

  At the origin position O, the outer surface of the piston 31a (the outer surface of the bottom of the bottomed cylinder) comes into contact with the engaging portion 11g which is the end surface of the large-diameter portion 11a of the first shaft 11, and the other piston 31b. The outer surface (the outer surface of the bottom of the bottomed cylinder) is in contact with the end surface of the large diameter portion 12a of the second shaft 12 on the first shaft 11 side.

  In the origin return mechanism 30, when the detection shaft 10 at the origin position O is displaced so as to be pushed into the housing 20, the outside of the piston 31 a is removed via the locking portion 11 g which is the end surface of the large diameter portion 11 a of the first shaft 11. The side surface (the outer surface of the bottom of the bottomed cylinder) is pushed in, and the other piston 31b cannot move in contact with the stepped surface 22h of the large-diameter hole portion 22f of the second housing 22, and resists the spring 31c. It can move by the detection stroke S until the cylindrical portions of the pistons 31a and 31b hit. When the force for pushing the detection shaft 10 disappears, the detection shaft 10 is returned to the origin position O by the spring force accumulated in the spring 31c.

  In the origin return mechanism 30, when the detection shaft 10 at the origin position O is displaced so as to be pulled out from the housing 20, the outer surface of the piston 31 b (the outer surface of the bottom of the bottomed cylinder) is the diameter of the second shaft 12. Pulled out through the end surface of the large portion 12a on the first shaft 11 side, the outer surface of the piston 31a (the outer surface of the bottom of the bottomed cylinder) abuts against the end surface 21f of the large-diameter hole portion 21a of the first housing 21 and moves. It cannot move, and it can move only the detection stroke S until the cylindrical part of two pistons 31a and 31b hits against the spring 31c. When the force for pulling out the detection shaft 10 is lost, the detection shaft 10 is returned to the origin position O by the spring force accumulated in the spring 31c. Note that a lubricant such as grease is applied to the outer peripheral surface of the piston housing portion 31d in which the pistons 31a and 31b are housed, and ensures stable sliding with respect to the second shaft 12 over a long period of time.

  The magnet 40 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 40 has a cylindrical shape using an SmCo sintered magnet, and two poles are magnetized in the vertical direction (magnet thickness direction) which is the major axis direction. The magnet 40 is housed in the magnet housing portion 11i of the first shaft 11 of the detection shaft 10 and is fixed with an adhesive or the like.

  The magnet 40 provides a magnetic field to the magnetic detection element 50 facing the magnet 40 of the first housing 21, and the direction (magnetic force) of the magnetic field applied to the magnetic detection element 50 when the magnet 40 is displaced together with the detection shaft 10. As a result, the magnetic detection element 50 detects the amount of movement. The magnet 40 may be either a sintered magnet or a plastic magnet that is 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 50 detects a displacement such as the amount of movement of the detected object, and is composed of, for example, a Hall element and converts a change in magnetic force accompanying the displacement such as the movement of the detected object into an electrical signal. Output to the outside. For example, the magnetic detection element 50 is configured as a magnetic detection package by mounting a plurality of Hall elements on the circuit board 51.

Here, the detection surface of the magnetic detection element 50 of the magnetic detection package is arranged in a direction perpendicular to the magnetization direction of the magnet 40. In the magnetic detection package including the magnetic detection element 50, the circuit board 51 is accommodated in the substrate accommodating portion 21g of the housing 20 (first housing 21), temporarily fixed to the positioning pins 21h and the female screw portion 21i with screws, and then a potting agent or the like. It is kept airtight by the seal member and the lid. By doing so, the gap with the magnet 40 is made as small as possible so that the change in the magnetic field can be detected with high accuracy.

  The power supply to the magnetic detection element 50 of the magnetic detection package and the output to the outside are performed by a direct connector or a cord. The magnetic detection element 50 may be mounted on a wire frame or the like and configured as a magnetic detection package.

  The detection of the stroke S in the magnetic detection package 9 using the magnetic detection element 50 is performed by using a plurality of Hall elements of the circuit board 51 and a magnetic field perpendicular to the magnetic detection surface of the magnetic detection element 50 of the magnetic field formed by the magnet 40 and horizontal. Detect the direction magnetic field. 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 S) of the detection shaft 10 are proportional, and as a result, the movement amount of the detection shaft 10 can be detected.

  Further, the output method from the magnetic detection package including the magnetic detection element 50 may be any method, and may be selected according to a control unit (ECU; Engine Control Unit) using the detection result ( For example, analog, PWM (Pulse Width Modulation), SENT (Single Edge Nibble Transmission), etc.).

  According to such a stroke sensor 1, since the detection shaft 10 is slidably supported by the sliding support portion 23 of the housing 20 so as to be slidable, the support width with respect to the entire length of the detection shaft 10 is increased. The contact area can be increased and supported, and the detection shaft 10 can be slid relative to the housing 20 in a stable state.

  Thereby, the gap between the magnet 40 attached to the detection shaft 10 whose rotation is restricted and the magnetic detection element 50 attached to the housing 20 can be made as small as possible, and a change in the magnetic field can be detected with high accuracy. Moreover, the small magnet 40 can be made by attaching the magnet 40 to the side surface of the detection shaft 10, and a stroke can be detected from a large change by concentrating the magnetic field.

  Further, since the detection shaft 10 slides relative to the housing 20 without rotating, the detection shaft 10 having a large contact area does not swing, and a part of the detection shaft 10 can be prevented from strongly hitting the housing 20. Durability can be improved by preventing local wear.

  In addition, since the magnet 40 and the magnetic detection element 50 serving as a magnetic detection unit are arranged on one side of the detection shaft 10 and the housing 20 and the origin return mechanism 30 is arranged on the other side, the detection shaft 10 and the housing 20 By making one side a non-magnetic material, even if the other side is made of a magnetic metal material, it is possible to detect a change in the magnetic field while minimizing the influence on the magnetic field. Thereby, durability can be improved by making the origin return mechanism 30 into a metal material.

  Further, by separating the ferrous material into nonmagnetic and magnetic materials on one side and the other side of the detection shaft 10 and the housing 20, the peripheral portion of the magnet 40 can be used as a nonmagnetic material to suppress the influence of the magnetic field change. The detection accuracy can be improved, and the other side can increase the degree of freedom of material selection.

  According to such a stroke sensor 1, the stroke sensor 1 has a magnet 40 and detects the amount of movement of the detection shaft 10 that reciprocates around the origin position O following the detected object by the magnetic detection element 50. The housing 20 that is slidably supported by restricting the rotation of the detection shaft 10, and the detection shaft 10 that is provided between the detection shaft 10 and the housing 20 after detecting the movement amount is moved to the origin position O. An origin return mechanism 30 for returning, and the origin return mechanism 30 is provided with a pair of pistons 31a and 31b and a spring 31c sandwiched between the pair of pistons 31a and 31b. A gap D <b> 1 is provided between the opposing inner wall surfaces of the housing 20.

  Therefore, the resistance force when the detection shaft 10 moves can be reduced, and a desired operational feeling (a constant operational feeling) can be provided. Further, the vibration of the pistons 31a and 31b can be suppressed by the spring 31c, and the detection accuracy by the magnetic detection element 50 can be improved.

In addition, a magnet 40 provided on the side surface of the detection shaft 10 and a magnetic detection element 50 provided on the housing 20 so as to face the magnet 40 and detecting a movement amount from a change in magnetic field accompanying the movement of the detection shaft 10 are provided. Therefore, the detection accuracy can be improved by the magnet 40 and the magnetic detection element 50 having a small gap, and the detection shaft that is slid while its rotation is regulated is supported by the housing 20 with an increased contact area. Wear can be reduced. Further, the gap between the magnetic detection element 50 attached to the housing 20 and the magnet 40 of the detection shaft 10 can be reduced, the fluctuation of the magnetic field can be reduced by suppressing the gap fluctuation, and the change of the magnetic field can be detected with high accuracy.

  According to the stroke sensor 1, the detection shaft 10 includes a first shaft 11 made of a nonmagnetic material and a second shaft 12 made of a magnetic material connected to the first shaft 11. Since the supporting first housing 21 is made of a nonmagnetic material, the materials used can be divided between the first shaft 11 and the first housing 21, and the second shaft 12 and the second housing 22, for example. By separating the iron-based material from non-magnetic and magnetic, the influence of the magnetic field change can be suppressed by using the peripheral portion of the magnet 40 as a non-magnetic material, and the detection accuracy can be improved.

  Further, according to the stroke sensor 1, the second shaft 12, the second housing 22 that houses the second shaft 12, and the origin return mechanism 30 that is housed in the second housing are made of a metal material, thereby providing magnetic It is possible to suppress the influence on the detection unit and to use the material in consideration of durability and strength, and to further improve the durability and strength.

  In the above-described embodiment, the detection shaft 10 is configured by connecting the first shaft 11 and the second shaft 12. However, the detection shaft 10 is configured by a single shaft, and only the large diameter portion 12a of the second shaft 12 is configured. You may make it attach with a screw. In this case, it is preferable to provide a positioning groove so that axial positioning can be performed.

  Further, in the above-described embodiment, the configuration in which the magnet is provided on the side surface of the detection shaft has been described. However, when the magnetic detection element can sufficiently obtain the position detection accuracy of the magnet, the magnet is installed on the axis side of the detection shaft. It can also be configured as follows.

DESCRIPTION OF SYMBOLS 1 Stroke sensor 10 Detection shaft 11 1st shaft 11a Large diameter part 11b Medium diameter part 11c Small diameter part 11d Male thread part 11e Female thread part 11f Centering groove 11g Locking part 11h Notch surface 11i Magnet accommodating part 12 2nd shaft 12a Large diameter Part 12b Diameter middle part 12c Small diameter part 12d Male thread 12e Stepped part 12f Locking part 20 Housing 21 First housing 21a Diameter large hole part 21b Diameter medium hole part 21c Small diameter hole part 21d Female thread part 21e Peripheral surface 21f End face 21g Substrate storage part 21h Positioning Pin 21i Female thread portion 22 Second housing 22a Large diameter portion 22b Small diameter portion 22c Male screw 22d Outer peripheral surface 22e Tip surface 22f Large diameter hole portion 22g Small diameter hole portion 22h Stepped surface 22i Female thread portion 23 Sliding support portion 30 Origin return mechanism 31a Piston 31b Piston 31c Spring 31d Piston storage 40 Magnet 50 Magnetic detection element 51 Circuit board O Origin position S Detection stroke

Claims (4)

A stroke sensor that has a magnet and detects the amount of movement of the detection shaft that reciprocates around the origin position following the object to be detected by a magnetic detection element,
A housing that slidably supports the rotation of the detection shaft; and
An origin return mechanism provided between the detection shaft and the housing for detecting the amount of movement and returning the detection shaft after the movement to the origin position;
The origin return mechanism includes a pair of pistons and a spring sandwiched between the pair of pistons,
The pair of pistons are provided with a gap between the opposed inner wall surfaces of the second housing. A magnet provided on a side surface of the detection shaft;
A magnetic detection element that is provided in the housing so as to face the magnet and detects the amount of movement from a change in the magnetic field accompanying the movement of the detection shaft,
The stroke sensor according to claim 1. The detection shaft includes a first shaft made of a nonmagnetic material and a second shaft made of a magnetic material connected to the first shaft,
A first housing supporting the first shaft is made of a non-magnetic material;
The stroke sensor according to claim 1. The second shaft, a second housing that houses the second shaft, and the origin return mechanism that is housed in the second housing are made of a metal material.
The stroke sensor according to claim 3.

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