JP2016114536A - Position detection sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position detection sensor with which it is possible to detect the position of a detection object with high accuracy, and for which downsizing is achieved.SOLUTION: A position detection sensor 101 has a magnet element 2 formed extending in one direction AD and magnetized so as to have a magnetic pole at both ends in the one direction AD, and a magnetism detection member 3 capable of detecting the direction of a magnetic field generated by the magnet element 2, and is characterized in that the magnetism detection member 3 is disposed facing the magnet element 2 on the side intersecting the one direction AD, detects the direction of a magnetic field changing along with the relative movement of the magnet element 2 and the magnetism detection member 3, and detects the position of a moving detection object, and the magnet element 2 has a base part M2 formed in shape of a rod in the one direction AD, and a protrusion part T2 formed at both ends in the one direction AD of the base part M2 and protruding at least toward the magnetism detection member 3 side.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a non-contact type position detection sensor that detects the position of a moving object to be detected.

  The non-contact type position detection device, for example, is more durable than the contact type position detection device that detects the position from the change of the output voltage accompanying the change of the contact position with the resistor. In addition to being excellent, it has the advantage that the movable part can be airtight. For this reason, it is used in a position sensor that measures the position (opening / closing angle, etc.) of an exhaust control valve or a turbocharger in an automobile, a pressure measuring device that measures the pressure of a liquid in home appliances, and the like.

  As a conventional example of such a position detection device, in Patent Document 1, a movable magnet 972 that moves with the movement of a detection object (movable body 904) and a sensor unit that detects the position of the movable magnet 972 (magnetoresistance effect element 976). A non-contact type position detecting device 900 using a position detecting sensor 950 having a FIG. 10 is an exploded perspective view of a position detection device 900 in a conventional example (Patent Document 1).

  A position detection apparatus 900 shown in FIG. 10 includes a position detection sensor 950 having a movable magnet 972 and a magnetoresistive effect element 976, a movable body 904 that moves by accommodating the movable magnet 972, and a magnetoresistive effect element 976. The sensor unit support 908 that fixes the substrate 957, the case 902 that houses the position detection sensor 950, the movable body 904, and the sensor unit support 908, and the lid 903 are configured.

  The position detection sensor 950 is provided with a magnetic body (protective plate 974) formed in a substantially U shape in plan view so as to surround the movable magnet 972 and the magnetoresistive element 976. Is assembled, the side plate portion 974a (first facing portion) of the protection plate 974 faces the movable magnet 972, and the side plate portion 974b (second facing portion) of the protection plate 974 is a magnetoresistive element. 976 comes to face. Thus, the opposing surface of the side plate portion 974a can reliably receive the magnetic flux from the movable magnet 972 and transmit it to the side plate portion 974b via the connecting portion 974c of the protection plate 974. By returning to the movable magnet 972 again via the side plate portion 974a, the connecting portion 974c, and the side plate portion 974b, the flow of the magnetic field detected by the magnetoresistive effect element 976 can be stabilized. For this reason, the position of the detection target (movable body 904) can be accurately detected without requiring a complicated operation for adjusting the relative positional relationship of each component, and a magnet or the like can be used corresponding to the stroke distance. Since it is not necessary to lengthen the position detection sensor 950, the position detection sensor 950 can be downsized.

JP 2010-185854 A

  However, since it has a magnetic body (protection plate 974) surrounding the movable magnet 972 and the magnetoresistive effect element 976 for the desire to further reduce the position detection sensor 950 of the conventional example, it is difficult to do so. there were. On the other hand, when the magnetic material (protection plate 974) of the conventional example is removed for downsizing, there is a problem that the good effect that the position of the detection target (detected object) can be accurately detected is lost. there were.

  The present invention solves the above-described problems, and an object of the present invention is to provide a position detection sensor that can accurately detect the position of an object to be detected and can be downsized.

  In order to solve this problem, a position detection sensor of the present invention is formed by a magnet body that is formed to extend in one direction and is magnetized to have magnetic poles at both ends in the one direction, and the magnet body. A magnetic detection member capable of detecting the direction of the magnetic field, the magnetic detection member being disposed on the side crossing the one direction so as to face the magnet body, and relative to the magnet body and the magnetic detection member. In the position detection sensor that detects the position of the moving object to be detected by detecting the direction of the magnetic field that changes along with the general movement, the magnet body has a base portion formed in a bar shape in the one direction; And a protruding portion that is formed at both end portions in the one direction of the base portion and protrudes at least toward the magnetic detection member.

  According to this, the position detection sensor of the present invention is formed so that the magnetic field generated by the magnet body connects the pair of protrusions, and is formed so as to follow the magnet body as compared with the case where there is no protrusion. The magnetic field region spreads to both ends of the magnet body and becomes stable. For this reason, even when the relative distance between the magnet body and the magnetic detection member changes due to assembly or the like, the difference from the magnetic field to be detected at a desired position is small, and deterioration in detection accuracy can be prevented. it can. In addition, since a stable magnetic field region extends to both ends of the magnet body, a longer detection region can be ensured without lengthening the magnet body. Accordingly, it is possible to provide a position detection sensor that can detect the position of the object to be detected with high accuracy and can be miniaturized.

  In the position detection sensor of the present invention, the protrusion height of the pair of protrusions may be a ratio of 0.11 to 0.27 with respect to the distance between the magnet body and the magnetic detection member. It is a feature.

  According to this, the balance between the projecting height of the projecting portion and the entire length of the magnet body is improved, and the magnetic field along the magnet body is stabilized by connecting the pair of projecting portions. As a result, it is possible to prevent a decrease in linearity accuracy when the detection accuracy, in particular, the relative distance between the magnet body and the magnetic detection member changes due to assembly or the like.

  The position detection sensor of the present invention is characterized in that the projecting portion is formed so as to project in all directions intersecting the one direction.

  According to this, in comparison with the case where the protruding portion is formed to protrude only on the magnetic detection member side, the protruding direction of the protruding portion is strictly aligned with the magnetic detection member when the position detection sensor is assembled. There is no need to do. As a result, the assembly of the position detection sensor is facilitated, and the relative positional accuracy between the projecting portion and the magnetic detection member is ensured, thereby preventing a decrease in detection accuracy.

  The position detection sensor according to the present invention is characterized in that the base portion is formed in a columnar shape, and the protruding portion is formed in a disk shape that is a concentric circle of the columnar shape.

  According to this, it is not necessary to position the protruding direction of the protruding portion when the position detection sensor is assembled, as compared with the case where the protruding portion is formed to protrude only on the magnetic detection member side. As a result, the assembly of the position detection sensor becomes easier, and the relative positional accuracy between the protrusion and the magnetic detection member is ensured, and the detection accuracy can be prevented from being lowered.

  In the position detection sensor of the present invention, the base portion and the protruding portion are formed of an integral permanent magnet.

  According to this, the number of parts can be reduced and assembly can be facilitated. Further, it is possible to ensure the dimensional accuracy and the placement position accuracy of the protruding portion, and it is possible to further prevent the detection accuracy from being lowered.

  The position detection sensor of the present invention is characterized in that the base portion is made of a permanent magnet and the protruding portion is made of a soft magnetic material.

  According to this, while being able to form the base part of a permanent magnet by a simple shape, the part formed with a permanent magnet can be reduced. This makes it possible to produce the magnet body easily and inexpensively.

  The position detection sensor of the present invention is characterized in that the protrusion has an attachment portion for fixing the magnet body.

  According to this, it can fix easily to the to-be-detected object side which moves, or the fixed side which does not move. In addition, the attachment portion can be easily manufactured as compared with the case of processing a permanent magnet.

  In the position detection sensor of the present invention, the magnetic field generated by the magnet body is formed so as to connect the pair of projecting portions, and the magnetic field region formed so as to follow the magnet body is smaller than the case where there is no projecting portion. It spreads to both ends of the and becomes stable. For this reason, even when the relative distance between the magnet body and the magnetic detection member changes due to assembly or the like, the difference from the magnetic field to be detected at a desired position is small, and deterioration in detection accuracy can be prevented. it can. In addition, since a stable magnetic field region extends to both ends of the magnet body, a longer detection region can be ensured without lengthening the magnet body. Accordingly, it is possible to provide a position detection sensor that can detect the position of the object to be detected with high accuracy and can be miniaturized.

It is a figure explaining the position detection sensor of 1st Embodiment of this invention, Comprising: It is a perspective view of the position detection apparatus with which the position detection sensor was applied. It is a figure explaining the position detection sensor of 1st Embodiment of this invention, Comprising: It is a top view of the position detection apparatus with which the position detection sensor was applied. FIG. 3 is a diagram illustrating the position detection sensor according to the first embodiment of the present invention, and FIG. 3 is a cross-sectional view of the position detection apparatus taken along line III-III shown in FIG. It is a figure explaining the position detection sensor of 1st Embodiment of this invention, Comprising: It is sectional drawing of a position detection apparatus when a magnet body moves upwards from the lower limit state of FIG. 3, and is located in an upper limit state. It is a figure explaining the position detection sensor of 1st Embodiment of this invention, Comprising: It is a perspective view of a magnet body. It is a schematic diagram explaining the position detection sensor of 1st Embodiment of this invention, Comprising: It is a cross-sectional block diagram of a magnet body and a magnetic detection member. It is a figure explaining the effect in the position detection sensor concerning a 1st embodiment of the present invention, and Drawing 7 (a) is a simulation result (A) of a position detection sensor, and Drawing 7 (b) is as a comparison. It is a simulation result (Z) of the comparative example performed. It is a figure explaining the effect in the position detection sensor concerning a 1st embodiment of the present invention, and Drawing 8 (a) is a simulation result (B) of a position detection sensor, and Drawing 8 (b) is position detection. It is a simulation result (C) of a sensor. FIG. 9A is a diagram for explaining the effect of the position detection sensor according to the first embodiment of the present invention, and FIG. 9A is a schematic diagram showing a magnetic flow generated by the magnet body, and FIG. FIG. 9 is a schematic view showing a comparative example in the case where no protrusion is provided, with respect to FIG. It is a disassembled perspective view of the position detection apparatus of a prior art example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
First, the position detection device 500 using the position detection sensor 101 according to the first embodiment of the present invention will be briefly described. FIG. 1 is a diagram illustrating a position detection sensor 101 according to the first embodiment of the present invention, and is a perspective view of a position detection device 500 to which the position detection sensor 101 is applied. FIG. 2 is a top view of a position detection apparatus 500 to which the position detection sensor 101 is applied. FIG. 3 is a cross-sectional view of the position detection apparatus 500 taken along the line III-III shown in FIG. In addition, in FIG. 3, the lower limit state which the magnet body 2 moved to the downward side is shown. 4 is a cross-sectional view of the position detection device 500 when the magnet body 2 moves upward from the lower limit state of FIG. 3 and is positioned in the upper limit state.

  The position detection device 500 has an appearance as shown in FIGS. 1 and 2, and as shown in FIGS. 3 and 4, the upper case K11 and the lower case K19 that form the appearance, and a one-way AD (see FIGS. 3 and 4). A position detection sensor 101 having a magnet body 2 that moves in the Z direction shown in FIG. 4 and a magnetic detection member 3 that can detect the direction of the magnetic field, a moving body 25 that can be driven integrally with the magnet body 2, and a magnet body. 2 and a drive unit 26 that moves 2. In addition, the position detection device 500 includes a guide member G17 that guides the movement of the magnet body 2 in one direction AD, a connector case H18 in which a connector CN for electrical connection with an external device is incorporated, and not illustrated. And a fitting F19 connected to a pneumatic control device such as a decompression source by a tube or the like. The position detection sensor 101 according to the first embodiment of the present invention will be described in detail after the outline of the position detection device 500 is described.

  First, the upper case K11 and the lower case K19 of the position detecting device 500 are manufactured by processing a metal material. When the upper case K11 and the lower case K19 are combined, they are shown in FIGS. Thus, the magnet body 2 and the drive part 26 are accommodated, and the accommodating part K1s in which the magnet body 2 is movable is formed.

  As shown in FIGS. 3 and 4, a guide member G17 is disposed in the housing portion K1s of the upper case K11, and a connector case is disposed above the outer side of the upper case K11 as shown in FIG. H18 is provided. Further, as shown in FIG. 1, the upper case K11 is provided with a fitting F19 extending from the side wall of the intermediate portion in a direction perpendicular to the side wall. The fitting F19 is formed in a hollow shape, and the housing portion K1s is connected to the outside through the hollow space.

  As shown in FIGS. 3 and 4, the lower case K19 has an opening K19h opened at the center, and a moving shaft J5 of the moving body 25 described later is inserted therethrough. The opening K19h keeps the inside of the accommodating portion K1s on the lower case K19 side at atmospheric pressure.

  Next, the moving body 25 of the position detecting device 500 can move integrally with the magnet body 2, and as shown in FIGS. 3 and 4, a holder portion H5 for fixing the magnet body 2 and a holder Piston portion P5 to which portion H5 is fixed, moving shaft J5 engaged with piston portion P5, and reinforcement disposed at the lower side of piston portion P5 (Z2 direction shown in FIG. 3) that engages with moving shaft J5. And a plate A5.

  The holder part H5 and the piston part P5 of the moving body 25 are injection-molded using a synthetic resin such as polybutylene terephthalate resin (PBT, polybutyleneterephtalate). Although not shown in detail, the piston part P5 is a cylinder. The bottom surface P5b has a hole at the center.

  The reinforcing plate A5 of the moving body 25 is made of a metal material, and although not shown in detail, it is formed in a disk shape and has a through hole at the center thereof. As shown in FIGS. 3 and 4, the reinforcing plate A5 is disposed at a position where the driving plate 26 (diaphragm D6 described later) is sandwiched between the reinforcing plate A5 and the bottom surface portion P5b of the piston portion P5.

  The moving axis J5 of the moving body 25 is made of a metal material, and is not shown in detail, but is formed in a substantially cylindrical shape. As shown in FIGS. 3 and 4, the moving shaft J5 has a tip on one side of the moving shaft J5 inserted through the hole of the piston portion P5 and the through hole of the reinforcing plate A5. It is fixed to the piston part P5 and the reinforcing plate A5 using a ring or the like. In addition, an operation target component (detected object) to be detected by the position detection device 500 is connected to the tip of the other side of the movement axis J5. In FIG. 1, the other end face has a flat cylindrical shape, but can be changed to various shapes for convenience of connection with the operation target component to be connected.

  Next, as shown in FIGS. 3 and 4, the drive unit 26 of the position detection device 500 includes a diaphragm D6 that divides the interior of the housing portion K1s into two spaces, and a biasing member F6 that biases the bottom 26b of the diaphragm D6. And is configured. The two spaces refer to a decompression chamber on the upper case K11 side of the diaphragm D6 and an atmosphere chamber on the lower case K19 side of the diaphragm D6.

  The diaphragm D6 of the drive unit 26 is made of an elastic rubber material, and as shown in FIGS. 3 and 4, a flange portion 26f sandwiched between the upper case K11 and the lower case K19, and a freely deformable member. And a bottom portion 26b having a through hole through which the moving shaft J5 is inserted. Further, as described above, since the bottom portion 26b of the diaphragm D6 is interposed between the bottom surface portion P5b of the piston portion P5 and the reinforcing plate A5, the vertical direction of the moving body 25 (shown in FIGS. 3 and 4). Even if the diaphragm D6 is deformed with the movement in the Z direction), the bottom portion 26b of the diaphragm D6 can be kept flat.

  The urging member F6 of the drive unit 26 is a coil spring whose both ends are flattened. As shown in FIGS. 3 and 4, one end abuts against the ceiling surface of the upper case K11 and the other end is the bottom surface of the piston part P5. It is in contact with the portion P5b. The urging member F6 urges the piston portion P5 downward.

  In the position detection device 500 configured as described above, when the decompression chamber is decompressed from the lower limit state shown in FIG. 3, the diaphragm D6 is deformed and resists the urging force of the urging member F6, and the bottom of the diaphragm D6. 26b moves upward (Z1 direction shown in FIG. 3). Then, when the force due to the decompression of the decompression chamber is greater than the urging force of the urging member F6, the bottom 26b of the diaphragm D6 is moved to the upper limit state of FIG. On the other hand, when the decompression of the decompression chamber is released, the bottom portion 26b of the diaphragm D6 is moved to the lower limit state of FIG. 3 by the biasing force of the biasing member F6. In this way, the magnet body 2 and the moving body 25 are moved in the vertical direction by the drive unit 26 moving in the vertical direction. The position detection device 500 detects the position of the moving object (operation target component to be detected) using the position detection sensor 101 according to the first embodiment of the present invention.

  Next, the position detection sensor 101 of the present invention will be described in detail. FIG. 5 is a perspective view of the magnet body 2. FIG. 6 is a schematic diagram illustrating the position detection sensor 101 according to the first embodiment of the present invention, and is a cross-sectional configuration diagram of the magnet body 2 and the magnetic detection member 3.

  The position detection sensor 101 according to the first embodiment of the present invention includes a magnet body 2 that moves in one direction AD (the Z direction shown in FIGS. 3 and 4) in the housing portion K1s in the upper case K11 and the lower case K19. And a magnetic detection member 3 for detecting the moving operation of the magnet body 2. The position detection sensor 101 is configured by disposing the magnetic detection member 3 so as to face the magnet body 2 on the side intersecting the one direction AD in which the magnet body 2 moves, and the magnet body 2 and the magnetic detection member 3. The magnetic detection member 3 detects the direction of the magnetic field that changes with relative movement. Thereby, the position of the detected object (operation target part to be detected) moving in conjunction with the magnet body 2 can be detected.

  First, as shown in FIG. 5, the magnet body 2 of the position detection sensor 101 is formed at a base portion M2 formed to extend in a bar shape in one direction AD and at both ends in the one direction AD of the base portion M2. And a protruding portion T2. The magnet body 2 is magnetized so as to have magnetic poles at both ends in one direction AD.

  The base portion M2 of the magnet body 2 is made of a permanent magnet such as a neodymium magnet, and is formed in a cylindrical shape as shown in FIG. Thereby, while being able to form the base part M2 with a simple shape, the part formed with a permanent magnet can be reduced. Thereby, the magnet body 2 can be manufactured easily and inexpensively.

  The projecting portion T2 of the magnet body 2 is made of a soft magnetic material such as iron or an iron alloy, and is formed in a disk shape having an outer shape that is a cylindrical concentric circle of the base portion M2, as shown in FIG. It is attached to both ends of the base part M2. In addition, in 1st Embodiment of this invention, although formed in the annular shape which provided the through-hole in the disk-shaped center part, it does not restrict to this, For example, the recessed part was provided in the base part M2 side. A configuration may be adopted in which the base portion M2 and the concave portion are fitted and mounted.

  When the position detection sensor 101 is assembled, as shown in FIGS. 3 and 4, a part of the protruding portion T <b> 2 protrudes toward the magnetic detection member 3 with respect to the magnetic detection member 3. It is arranged. Thereby, the magnetic field generated by the magnet body 2 is formed so as to connect the pair of projecting portions T2, and the magnetic field region formed along the magnet body 2 is compared with the case where the projecting portion T2 is not provided. Will spread to both ends. In other words, a parallel magnetic field is formed by the magnet body 2 at both ends of the magnet body 2, a magnetic field area parallel to the magnet body 2 is expanded, and the magnetic field area received by the magnetic detection member 3 is stabilized. For this reason, a longer detection region can be secured without lengthening the magnet body 2.

  Moreover, in 1st Embodiment of this invention, since the protrusion part T2 is formed in the disk shape and is mounted | worn with the cylindrical base part M2, the protrusion part T2 protrudes in all the directions which cross | intersect one direction AD. It is comprised so that it may be formed. Thereby, compared with the case where the protruding portion T2 protrudes only on the magnetic detection member 3 side, the protruding direction of the protruding portion T2 is strictly set with respect to the magnetic detection member 3 when the position detection sensor 101 is assembled. Therefore, the position detection sensor 101 can be easily assembled.

  Further, the protrusion height TH (see FIG. 6) of the pair of protrusions T2 is set to the same height, and the surface of the magnet body 2 on the magnetic detection member 3 side and the magnetic detection of the magnetic detection member 3 are set. A ratio of 0.11 to 0.27 is preferable for the distance SD between points (see FIG. 6). Thereby, the balance between the projecting height TH of the projecting portion T2 and the entire length of the magnet body 2 is improved, and the magnetic field along the magnet body 2 formed so as to connect the pair of projecting portions T2 becomes stable. The width TW (see FIG. 6) of the protruding portion T2 is preferably set to be equal to or slightly wider than the width of the magnetic detection member 3.

  Further, as shown in FIG. 5, a mounting portion T <b> 2 r for fixing the magnet body 2 to the holder portion H <b> 5 of the moving body 25 is formed on the protruding portion T <b> 2 made of a soft magnetic body. In the first embodiment of the present invention, the attachment portion T2r is a through hole, and the magnet body 2 can be easily fixed by screwing the protruding portion T2 using a screw or the like. Moreover, since it is protrusion part T2 which consists of a soft magnetic body, compared with the case where a permanent magnet is processed and the attachment part T2r is provided, the attachment part T2r can be produced easily.

  Finally, the magnetic detection member 3 of the position detection sensor 101 uses two Hall elements. Although not shown in detail, the magnetic detection member 3 is packaged with a thermosetting synthetic resin together with a semiconductor element, It is mounted on the board. These two Hall elements have sensitivity axes in the Z direction and the X direction shown in FIG. And the magnetism detection member 3 is arrange | positioned facing the magnet body 2 on the side which cross | intersects one direction AD, detects the change of the magnetic field accompanying the operation | movement of the up-down direction of the magnet body 2, with a biaxial Hall element, The position of the magnet body 2 is detected.

  As described above, since the magnetic field region received by the magnetic detection member 3 is stable in the position detection sensor 101, the relative distance between the magnet body 2 and the magnetic detection member 3 changes due to assembly or the like. Even in this case, the difference between the magnetic detection member 3 and the magnetic field that should be detected at a desired position is small, and a decrease in detection accuracy is prevented. In particular, a decrease in detection accuracy at both end portions of the magnet body 2 is prevented as compared with a case where the protruding portion T2 is not provided.

[Example]
The position detection sensor 101 configured as described above was simulated and the effect was verified. FIG. 7 is a diagram for explaining the effect of the position detection sensor 101. FIG. 7A is a simulation result (A) of the position detection sensor 101, and FIG. 7B is a comparison performed as a comparison. It is a simulation result (Z) of an example. The vertical axis in FIG. 7 is the ratio of the difference (variation difference) to the output value of the magnetic detection member 3 obtained at the position of the reference interval distance SD, and the horizontal axis in FIG. 7 is the movement of the magnetic detection member 3. The stroke ST to be performed. FIG. 8 is a diagram for explaining the effect of the position detection sensor 101. FIG. 8A is a simulation result (B) of the position detection sensor 101, and FIG. 8B is a position detection sensor. 101 is a simulation result (C). The vertical axis in FIG. 8 is the ratio of the difference (variation difference) to the output value of the magnetic detection member 3 obtained at the position of the reference interval distance SD, and the horizontal axis in FIG. This is the ratio of the magnet body length ML, and the horizontal axis in FIG. 8B is the ratio of the protrusion height TH to the interval distance SD. For easy understanding, FIG. 8A shows a simulation result of the comparative example (Z1 shown in the figure) by a two-dot chain line. FIG. 9 is a diagram for explaining the effect of the position detection sensor 101. FIG. 9A is a schematic diagram showing a simulation result showing the flow of magnetism generated by the magnet body 2, and FIG. FIG. 10 is a schematic diagram illustrating a simulation result of a comparative example in the case where the protrusion T <b> 2 is not provided with respect to FIG. 9A.

  Each size used in the simulation (the size shown in FIG. 6) has the following values. First, as a size common to FIGS. 7 and 8, the reference distance SD is fixed to 7.25 (mm), and the distance SD of ± 2 (mm) varies from this reference value. The solid line value shown in FIG. 7 indicates the result when the reference value is deviated by +2 (mm), and the broken line value shown in FIG. 7 indicates the result when the reference value is deviated by −2 (mm). . Moreover, the stroke ST in which the magnetic detection member 3 moves was fixed at 12 (mm). The stroke ST shown in FIG. 7 represents the position facing the center of the magnet body length ML as “0”.

  Next, in FIG. 7, the magnet body length ML of the magnet body 2 is fixed to 25 (mm), and the base portion diameter MW is fixed to 10.7 (mm). In FIG. 7A, the width TW of the protrusion T2 is fixed to 2.5 (mm), and the protrusion height TH is fixed to 1.6 (mm). In this case, the ratio of the magnet body length ML to the stroke ST is 2.1, and the ratio of the protrusion height TH to the interval distance SD is 0.22. Moreover, in FIG.7 (b), since it was a comparative example, it was set as the structure which does not provide the protrusion part T2.

  Next, in FIG. 8A, the magnet body length ML of the magnet body 2 is varied from 12 (mm) to 30 (mm), and the base part diameter MW of the magnet body 2 is fixed to 10.7 (mm). The protrusion height TH was fixed at 1.6 (mm), and the width TW of the protrusion T2 was fixed at 2.5 (mm). In this case, the ratio between the protrusion height TH and the distance SD is 0.22. Finally, in FIG. 8B, the magnet body length ML of the magnet body 2 is fixed to 30 (mm), the base portion diameter MW is fixed to 10.7 (mm), and the width TW of the protruding portion T2 is set to 2. The protrusion height TH was varied from 1.0 (mm) to 3.6 (mm). Note that the ratio of the magnet body length ML to the stroke ST at this time is 2.5.

  As shown in FIG. 7A, the position detection sensor 101 according to the first embodiment of the present invention is magnetic as shown in FIG. 7A compared with the result (Z) of the comparative example that does not have the protrusion T2 shown in FIG. The output value fluctuation difference (linearity) obtained by the detection member 3 is greatly reduced. As shown in FIG. 9A, the magnetic field generated by the magnet body 2 is formed so as to connect the pair of protrusions T <b> 2, and the magnetic field regions formed along the magnet body 2 are at both ends of the magnet body 2. This is because it spreads to the side and is stable. On the other hand, in the comparative example that does not have the projecting portion T2, as shown in FIG. 9B, the magnetic field is formed so as to connect both end portions of the magnet body 702 and along the magnet body 702. Is narrowing. As described above, the position detection sensor 101 has a small difference from the magnetic field to be detected at a desired position even when the relative distance between the magnet body 2 and the magnetic detection member 3 changes due to assembly or the like. Therefore, it is possible to prevent a decrease in detection accuracy.

  Further, the position detection sensor 101 is obtained by the magnetic detection member 3 at any magnet body length ML as shown in FIG. 8A, as compared with the simulation result Z1 of the comparative example shown in FIG. The difference in output value (linearity) is greatly reduced. This means that a longer detection area can be secured without lengthening the magnet body 2. On the contrary, when it is going to obtain the same fluctuation | variation difference (linearity), the ratio of the magnet body length ML with respect to stroke ST can be made smaller than a comparative example. That is, the magnet body length ML can be shortened, and the position detection sensor 101 can be downsized.

  Further, as shown in FIG. 8B, the protrusion height TH of the protrusion T2 in the position detection sensor 101 is a minimum value in the ratio of the distance to the distance SD (about 0.21 in FIG. 8B). have. That is, as the ratio of the protrusion height TH to the interval distance SD increases, the linearity gradually increases, and when the ratio exceeds a certain ratio (local minimum value), the linearity gradually decreases. This is a ratio in which the protrusion height TH of the protrusion T2 and the total length of the magnet body 2 (magnet length ML) are balanced, and the magnetic field along the magnet body 2 is formed so as to connect the pair of protrusions T2. This is because it becomes stable. Thereby, it is preferable that the protrusion height TH of the pair of protrusions T2 is a ratio of 0.11 to 0.27 with respect to the distance SD between the magnet body 2 and the magnetic detection member 3.

  The effects of the position detection sensor 101 according to the first embodiment of the present invention configured as described above will be collectively described below.

  The position detection sensor 101 according to the first embodiment of the present invention has protrusions T2 that protrude toward the magnetic detection member 3 at both ends of a base part M2 in which the magnet body 2 is formed in a bar shape in one direction AD. Therefore, the magnetic field generated by the magnet body 2 is formed so as to connect the pair of projecting portions T2, and the magnetic field region formed along the magnet body 2 is compared to the case where the projecting portion T2 is not provided. It spreads to both ends and becomes stable. For this reason, even when the relative distance between the magnet body 2 and the magnetic detection member 3 is changed due to assembly or the like, the difference from the magnetic field to be detected at a desired position is small, thereby preventing a decrease in detection accuracy. be able to. In addition, since a stable magnetic field area extends to both ends of the magnet body 2, a longer detection area can be secured without lengthening the magnet body 2. Accordingly, it is possible to provide the position detection sensor 101 that can accurately detect the position of the object to be detected and can be downsized.

  Further, since the protrusion height TH of the pair of protrusions T2 is a ratio of 0.11 to 0.27 with respect to the distance SD between the magnet body 2 and the magnetic detection member 3, the protrusion height of the protrusion T2 is as follows. The balance between the length TH and the entire length of the magnet body 2 is improved, and the magnetic field along the magnet body 2 is stabilized by connecting the pair of protrusions T2. Thereby, it is possible to prevent a decrease in linearity accuracy when the detection accuracy, in particular, the relative distance between the magnet body 2 and the magnetic detection member 3 changes due to assembly or the like.

  Further, since the protruding portion T2 is formed so as to protrude in all directions intersecting the one direction AD, the position detection is performed as compared with the case where the protruding portion T2 is formed to protrude only on the magnetic detection member 3 side. When the sensor 101 is assembled, it is not necessary to strictly align the protruding direction of the protruding portion T2 with respect to the magnetic detection member 3. As a result, the assembly of the position detection sensor 101 is facilitated, and the relative positional accuracy between the projecting portion T2 and the magnetic detection member 3 is ensured, and a decrease in detection accuracy can be prevented.

  Further, since the projecting portion T2 is formed in a disk shape that is a cylindrical concentric circle of the base portion M2, position detection is performed as compared with the case where the projecting portion T2 is projected only on the magnetic detection member 3 side. When the sensor 101 is assembled, it is not necessary to position the protruding direction of the protruding portion T2. As a result, the position detection sensor 101 can be assembled more easily, and the relative positional accuracy between the protruding portion T2 and the magnetic detection member 3 can be ensured, and the detection accuracy can be prevented from being lowered.

  Further, since the base portion M2 of the magnet body 2 is a permanent magnet and the protruding portion T2 of the magnet body 2 is a soft magnetic body, the base portion M2 of the permanent magnet can be formed in a simple shape and formed with a permanent magnet. Can be reduced. Thereby, the magnet body 2 can be manufactured easily and inexpensively.

  Further, since the protruding portion T2 has an attachment portion T2r for fixing the magnet body 2, it can be easily fixed to the moving object to be detected. Further, since the protruding portion T2 is made of a soft magnetic material, the mounting portion T2r can be easily manufactured as compared with the case of processing a permanent magnet.

  In addition, this invention is not limited to the said embodiment, For example, it can deform | transform and implement as follows, These embodiments also belong to the technical scope of this invention.

<Modification 1>
In the first embodiment, the base portion M2 of the magnet body 2 is configured as a permanent magnet, and the protruding portion T2 of the magnet body 2 is configured as a soft magnetic material. However, the base portion M2 and the protruding portion of the magnet body 2 are integrated. You may comprise as a permanent magnet. Thereby, the number of parts can be reduced and assembly can be facilitated. Further, it is possible to ensure the dimensional accuracy and the arrangement position accuracy of the protruding portion, and it is possible to prevent a decrease in detection accuracy.

<Modification 2>
In the first embodiment, the protrusion T2 is formed to protrude in all directions intersecting the one direction AD. However, the present invention is not limited to this, and the protrusion protrudes at least toward the magnetic detection member 3 side. If it is good.

<Modification 3>
In the said 1st Embodiment, although it was set as the structure formed in the disk shape which the protrusion part T2 becomes a cylindrical concentric circle of the base part M2, it is not restricted to this. For example, the protruding portion may be formed in a polygonal shape, and the protruding height TH of the protruding portion corresponding to the side may be changed. Thereby, the distance SD between the magnet body 2 and the magnetic detection member 3 can be changed depending on the case, and the optimal protrusion height TH of the protrusion can be set in accordance with the change. .

<Modification 4>
In the first embodiment, a simple through hole is used as the attachment portion T2r. However, the present invention is not limited to this. For example, a hook-like attachment portion extended from a disk-shaped protrusion T2 may be used. In that case, it is more preferable to provide an attachment part in the protrusion part on the opposite side to the side facing the magnetic detection member 3.

<Modification 5>
In the first embodiment, a simple cylindrical columnar permanent magnet is used as the base portion M2 of the magnet body 2. However, the present invention is not limited to this. For example, a cylindrical permanent magnet is used as the base. You may comprise a part. In that case, a magnet holder having a columnar shaft portion may be used, and the shaft portion may be inserted into a cylinder of the base portion to hold the magnet body. Furthermore, this shaft part may be provided in the holder part H5 of the moving body 25 to form a magnet holder.

<Modification 6>
In the first embodiment, the Hall element is used as the magnetic detection member 3, but the present invention is not limited to this. For example, a GMR (Giant Magneto Resistive) element, an MR (Magneto Resistive) element, and an AMR (Anisotropic Magneto Resistive) element A TMR (Tunnel Magneto Resistive) element or the like may be used.

<Modification 7>
In the first embodiment, the example in which the position detection sensor 101 is applied to the position detection device 500 has been described. However, the present invention is not limited to this, and the position detection sensor of the present invention is a moving object to be detected. It can utilize suitably for the apparatus which detects this position.

  The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the scope of the object of the present invention.

2 Magnet body M2 Base part T2 Protrusion part T2r Mounting part 3 Magnetic detection member AD Unidirectional SD Spacing distance TH Projection height 101 Position detection sensor

Claims (7)

A magnet body formed to extend in one direction and magnetized to have magnetic poles at both ends in the one direction, and a magnetic detection member capable of detecting the direction of the magnetic field generated by the magnet body,
The magnetic detection member is disposed opposite the magnet body on the side intersecting the one direction;
In the position detection sensor that detects the position of the moving detection object by detecting the direction of the magnetic field that changes with relative movement of the magnet body and the magnetic detection member,
The magnet body has a base portion formed in a bar shape in the one direction, and protrusions formed at both ends of the base portion in the one direction and projecting at least toward the magnetic detection member. Position detection sensor.   2. The position according to claim 1, wherein a protrusion height of the pair of protrusions is a ratio of 0.11 to 0.27 with respect to a distance between the magnet body and the magnetic detection member. Detection sensor.   The position detection sensor according to claim 1, wherein the protrusion is formed so as to protrude in all directions intersecting the one direction. The base portion is formed in a cylindrical shape,
The position detection sensor according to any one of claims 1 to 3, wherein the protruding portion is formed in a disk shape that is the cylindrical concentric circle.   The position detection sensor according to claim 1, wherein the base portion and the protruding portion are formed of an integral permanent magnet. The base portion is made of a permanent magnet,
The position detection sensor according to claim 1, wherein the protrusion is made of a soft magnetic material. The position detection sensor according to claim 6, wherein the protrusion has an attachment portion for fixing the magnet body.