JP2015038527A - Position detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position detector which can expand a range in which highly accurate position detection can be performed with a small number of components.SOLUTION: The position detector includes a stationary member 4 to which a wiring board 2 having a hall element 3 is fixed, and a movable member 5 which is supported so as to be movable within a prescribed range with respect to the stationary member 4. The movable member 5 has a pair of detection magnet members 6a, 6b arranged so as to be up-grade from one end side to the other end side along the movement direction. The detection magnet members have single permanent magnets magnetized in the thickness direction and are arranged so that the gap facing the hall element changes from the one end to the other end in the movement direction.

Description

The present invention relates to a position detection device that uses a Hall element to detect the absolute position of a linearly driven member in a non-contact manner.

  In an optical apparatus such as a digital still camera or a video camera, a zoom operation and a focus operation are performed by linearly moving an optical element such as a lens. In order to perform these operations automatically, an optical position detection device has been conventionally used.

  In an optical position detection device, in order to obtain high resolution and good responsiveness, a semiconductor position detection element (PSD) in which a continuous electric signal is obtained and a material that generates a voltage corresponding to the amount of light is uniformly applied. Is used. However, in this position detection device, a light emitting element (LED) is required to irradiate the light receiving surface of the PSD with the spot light. This increases the cost and installation space, and further emits light by dust, oil, etc. It is difficult to secure an optical path for reading, and reading accuracy is likely to decrease.

In order to solve such problems, a linear potentiometer that detects the voltage corresponding to the position of the brush of the resistor by sliding the brush on a distance information resistor provided on the outer peripheral surface such as a focus ring. Such a magnetic position detecting device is also used. However, this position detection device has a complicated structure and is not suitable for customization, has a low degree of freedom for the required linear output, and requires a thrust to slide due to the sliding resistance of the brush and resistor. There is a drawback that it is not suitable for mounting on a portion where load driving or high speed driving is required.

  Therefore, a non-contact type position detection device using a magnetic field detection element has been proposed (see Patent Document 1). In this type of position detection apparatus, a relative position detection apparatus using, for example, a magnetoresistive effect element (MR element) is used as a magnetic field detection element (see Patent Document 2). According to this position detection device, the movable member is linearly moved from the reference position toward the target position, and in this movement process, the magnetic sheet (encoder magnet) subjected to multipolar magnetization in the optical axis direction by the MR element is used. By detecting the change in magnetic flux density and counting the electrical signal output from the MR element, the absolute position of the driven member (lens) in the optical axis direction is detected and until the difference between the target position and the current position disappears Driven.

However, the resolution of the MR element is generally 150 to 200 μm, and high-accuracy positioning cannot be performed as it is. Therefore, in order to obtain high positioning accuracy, it is necessary to multiply the output of the MR element. There is a problem that a large-scale signal processing circuit is required and noise resistance characteristics are deteriorated. Therefore, it has been proposed to use a GMR element having a resolution of 20 to 40 μm instead of the MR element. However, since the GMR element needs to be substantially in contact with the magnetic sheet, sliding noise is generated, which causes a problem that it cannot cope with moving images, and the driven member (for example, the focus lens) is smooth due to sliding friction. There is also a problem that the movement is hindered and the positioning accuracy is lowered.

  Furthermore, in a position detection apparatus using an MR element or a GMR element, a reset sensor (for example, a photo interrupter) is provided on a fixed member in order to first convert a measurement position into an absolute value (detect a reference position), Since the driven member is provided with a light shielding member, and the driven member is moved so that the light shielding member blocks the optical path of the photo interrupter, the sensor output changes from H (L) to L (H). It is necessary to detect the position at the time and use the detected position as a reference position. If the magnetoresistive effect element or the giant magnetoresistive effect element is used in this way, a reset sensor for detecting the reference position is required in addition to the magnetic field detecting element and the magnet for the encoder, which increases the size and cost of the position detecting device. Will be invited.

Therefore, it has been proposed to use a Hall element that does not require a reset sensor as a position detection device and that can obtain an output voltage substantially proportional to the moving distance in a range where the magnetic flux density changes linearly. However, in the structure in which the Hall element is opposed to a flat plate-like permanent magnet that is magnetized in the thickness direction and in which N and S poles are arranged, the gap magnetic flux density has a sinusoidal or trapezoidal waveform, and the magnetic flux density is linear. There is a drawback that the range of change is limited to a narrow range (about 1 to 2 mm) near the boundary of the magnetic poles. In addition, if a flat permanent magnet is used to increase the range in which the magnetic flux density changes linearly, it is necessary to lengthen the magnet to about 10 to 20 times the moving distance of the Hall element, and as a product Becomes unusable. Therefore, as described in Patent Document 3, there has been proposed a position detection device having two Hall elements and multi-pole magnetized position detection magnets. In addition to this, as described in Patent Document 4, in order to improve the linearity of the output of the Hall element, a rectangular magnet that moves relative to the Hall element is covered with a U-shaped yoke, and the sectional shape of the yoke Has been proposed to vary along the longitudinal direction.

  However, if a plurality of Hall elements are used as described in Patent Document 3, high detection accuracy can be obtained in a wide range, but the number of parts increases and the signal processing circuit becomes more complicated, resulting in increased costs. There is a problem. The position detection device described in Patent Document 4 has the following problems. As described in Patent Document 3, a structure in which a columnar detection magnet is covered with a yoke whose cross-sectional shape perpendicular to the longitudinal direction changes in the longitudinal direction increases the number of parts and increases the cost, which is problematic in practicality.

Japanese Utility Model Publication No. 2-131614 Japanese Patent Laid-Open No. 2002-214501 JP 2010-96540 A WO 06/115129 Pamphlet

  Accordingly, an object of the present invention is to provide a position detection device capable of expanding the range in which position detection with high accuracy can be performed with a small number of parts.

  In order to achieve the above object, a position detection apparatus according to the present invention includes a Hall element fixed at a predetermined position and a detection magnet member that is opposed to the Hall element and supported so as to be relatively movable. The detection magnet member includes a pair of permanent magnets magnetized in the thickness direction and adjacent to the magnetic poles of different polarities along the moving direction, and the Hall element toward the boundary between the two magnets. It arrange | positions so that the gap which opposes may increase, It is characterized by the above-mentioned.

  In the present invention, the magnet member for detection has a single permanent magnet magnetized in the thickness direction, and the gap facing the Hall element changes from one end to the other end in the moving direction. It can be set as the structure arrange | positioned.

  In the present invention, each of the detection magnets is composed of an R—Fe—B based sintered magnet (where R is one or more of rare earth elements including Y and necessarily includes Nd), and each of the detection magnets. It is preferable to mount a magnetic shield member on the magnetic pole surface opposite to the detection magnetic pole surface.

  In the present invention, the Hall element is mounted on the fixed member while being mounted on the wiring board, and the movable member can be supported so as to be movable within a predetermined range with respect to the fixed member.

  In the present invention, the gap between the magnetic sensing surface of the Hall element and the detection magnetic pole surface of the detection magnet is 0.3 mm or more and less than 2 mm (more preferably 0.5 mm to 1.5 mm) at the narrowest position. It is preferable to set.

  In the position detection sensor of the present invention, each of the detection magnets is preferably installed such that the detection magnetic pole surface is inclined by an angle range of 20 ° to 30 ° with respect to a straight line parallel to the magnetic sensing surface of the Hall element. .

  According to the present invention, the magnetic flux density that linearly changes over a predetermined range is detected by a single Hall element by arranging the detection magnet at a specific position while maintaining the size of the detection magnet. Even with a simple structure, position control of a linearly driven optical element or the like can be performed with high accuracy. In addition, since the Hall element is not in contact with the detection magnet, it is suitable for mounting on a portion that is required to be driven at a low load or at a high speed. In addition, parts other than the Hall element and detection magnet (a yoke is used if necessary) are not required, and linear output can be obtained without being affected by dust, dust, oil, etc. Have sex.

In addition, a single-pole magnetized plate-like permanent magnet that does not require a dedicated molding die or magnetizing device is used as the detection magnet, and a reset sensor is not required. It can be simplified and cost reduction can be achieved.

If the output value for the moving position is converted into a specific value, it is possible to obtain absolute position information. In addition, since the output zero-cross position (the boundary position between the N pole and the S pole) is uniquely determined by the magnet position, the positioning accuracy of the portion to be fixed is proportional to the mechanical accuracy, and therefore variations in the optical axis direction can be reduced. Therefore, if the zero cross position is set to the initial position, the initialization component (for example, a photo interrupter) can be omitted.

In particular, since the initialization position is in the middle of the movement range, the movement distance required for setting the origin, that is, the origin setting time, is halved as compared with the conventional photo interrupter, so that the sensing speed can be increased.

Since an analog voltage proportional to the moving distance is output from the Hall element, the resolution can be increased by increasing the reading accuracy. In addition, since the length dimension in the optical axis direction may be set equal to the movement length, the length is 1/10 to 1/30 times that when the detection magnet is arranged parallel to the optical axis direction (focus movement). (When the amount is 10 to 30 mm), it is possible to achieve compactness.

Since the gap between the Hall element and the detection magnet may be set to 0.3 mm or more, unlike the combination of the MR element and the magnetic sheet having a very narrow magnetization pitch (10 to 20 μm), Since it is not necessary to strictly manage the gap, the gap range is widened and the assembly operation is easy.

Since the gap between the Hall element and the detection magnet may be set to 0.3 mm or more, unlike the combination of the GMR element and the magnetic sheet having a very narrow magnetization pitch (10 to 20 μm), the Hall element and the detection magnet are not As a result of the contact, smooth movement is ensured and durability is improved.

It is a disassembled perspective view which shows the position detection apparatus concerning embodiment of this invention. It is sectional drawing which cut | disconnected the position detection apparatus (after an assembly) of FIG. 1 by the AA line. It is a figure which shows the use condition of the position detection apparatus of FIG. 1 typically, and is a figure which shows the state which has a Hall element in an initial position. It is a figure which shows an example of the signal processing circuit of the position detection apparatus concerning embodiment of this invention. It is a figure which shows the use condition of the position detection apparatus concerning other embodiment of this invention typically, and is a figure which shows the state which has a Hall element in an initial position. It is a figure which shows magnetic flux density distribution in the Hall element surface of the position detection apparatus shown in FIG. It is a figure which shows magnetic flux density distribution in the Hall element surface of the position detection apparatus shown in FIG. It is a figure which shows typically the use condition of the position detection apparatus concerning a 1st comparative example, and is a figure which shows the state which has a Hall element in an initial position. It is a figure which shows typically the use condition of the position detection apparatus concerning a 2nd comparative example, and is a figure which shows the state which has a Hall element in an initial position.

  Details of the present invention will be described below with reference to the accompanying drawings. In the following description, the same functional parts are denoted by the same reference numerals.

[Position detection device]
As shown in FIGS. 1 and 2, the position detecting device 1 is movable to the Hall element 3 mounted on the surface of the wiring board 2, the fixing member 4 that fixes the wiring board 2 at a predetermined position, and the fixing member 4. The movable member 5 having the detecting magnet members 6a and 6b supported by the motor is provided. Details of each part of the position detection device 1 are as follows.

(Wiring board)
The wiring board 2 is provided with a pair of positioning recesses 22a and 22b that are fitted to the fixing member 4 and fixed at a predetermined position on a flat surface, and one end side in the long side direction (Z direction). The Hall element 3 is mounted on.

(Fixing member)
The fixing member 4 includes a rectangular fixing frame 41 having two rows of leg portions 410a and 410b extending along the Z-axis direction at the lower portion, and a wiring board in a space portion 42 formed between the leg portions 410 and 410b. 2 is inserted. Screw parts 21a and 21b formed on the surface of the wiring board 2 are screwed into protrusions 45a (not shown) and 45b formed on the bottom part 43 of the fixed frame 41, respectively. In order to support the movable member 5 movably in the Z direction, the fixed frame 41 is formed with rectangular notches 46a and 46b on one end side and the other end side (short side portion) in the Z direction, Guide shafts 47a and 47b are attached along the Z direction so as to sandwich notches 46a and 46b.

(Movable member)
The movable member 5 includes a holding member 51 and detection magnet members 6a and 6b attached thereto. The holding member 51 is a member in which the surface not facing the hall element 3 is formed in an H-shape, and when viewed from the longitudinal section (see FIG. 2), the holding member 51 is separated from the slope 52a having an upward slope from one end toward the partition portion 52c. It has the slope 52b which becomes a downward slope toward the other end from the part 52c. A pair of magnet members for detection 6a and 6b are installed on the slopes 52a and 52b, respectively. One detection magnet member 6a has a flat plate-like permanent magnet 7a magnetized in the thickness direction and a flat plate-like yoke 8a made of a ferromagnetic material (for example, a steel material) fixed to the back side thereof. The other detection magnet member 6b is composed of a flat plate-like permanent magnet 7b magnetized in the thickness direction so that magnetic poles of different polarities are adjacent to each other, and a flat plate-like yoke 8b made of a ferromagnetic material fixed to the back side thereof. Have With this magnet arrangement, a closed magnetic circuit passing through the Hall element 3 is formed from the detection magnet members 6a to 6b.

The holding member 51 has sliding portions 53a and 53b through which one guide shaft 47a is inserted on one side surface. On the other side surface of the holding member 51, an arm portion 54 orthogonal to the Z direction is formed, and at the base of the arm portion 54, a guide hole 56a through which the other guide shaft 47b is inserted is formed. An extending portion 55 having a guide hole 56b through which the guide shaft 47b is inserted is formed on the end side of the portion 54.

(Magnetic member for detection)
As shown in FIG. 3, each of the detecting magnet members 6a and 6b is arranged so as to exhibit an inverted V shape when viewed from a direction perpendicular to the paper surface. That is, the permanent magnets 7a and 7b are held by the movable member 5 so as to be inclined by angles α1 and α2 with respect to a straight line parallel to the arrow Z. Therefore, the gap between the magnetic sensing surface of the Hall element 3 and the magnetic pole surface of the permanent magnet 7a is monotonous from the position where one end of the permanent magnet 7a and one end of the permanent magnet 7b approach or contact each other toward the other end of each magnet. The gap gh1 between the magnetic sensing surface of the Hall element 3 and the magnetic pole surface of the permanent magnet 7b is also arranged so as to monotonously decrease. Here, if the gap gh1 is too narrow, the magnetic flux waveform tends to be distorted, and if it is too wide, the curved portion increases and the linear region becomes short. It is preferably set to 3 mm or more and less than 2 mm, and more preferably in the range of 0.5 to 1.5 mm. The angle α1 and the angle α2 may be the same or different, but are preferably set in the range of 20 ° to 30 °.

  By arranging the detection magnet in this way, the magnetic flux density on the magnetic sensing surface of the Hall element 3 changes linearly over almost the entire length of the magnet, and the output voltage of the Hall element 3 also changes linearly. At the initial position where the magnetic flux density is zero, the output voltage of the Hall element is also zero. As the Hall element 3 moves in the Z direction from this initial position, the magnetic flux density detected by the Hall element changes linearly. As a result, the voltage output from the Hall element monotonously increases or decreases, so that the current position can be accurately grasped.

  The detection magnet can be formed of a known permanent magnet regardless of the material, but from the viewpoint of noise resistance, the input circuit side gain is set low and the sensor unit can be downsized. It is preferable to use rare earth magnets, for example, R—Fe—B based sintered magnets (where R is one or more of rare earth elements including Y and necessarily includes Nd).

(Hall element)
The output voltage of the Hall element depends on the electron mobility and Hall coefficient of the material, and is usually formed of an N-type semiconductor thin film (thickness of several μm) made of a III-V group compound such as GaAs, InSb, InAs or the like. Hall elements are used. In the present invention, in order to enable highly accurate position control, it is preferable to use a Hall element made of GaAs having a small Hall coefficient temperature coefficient (about −0.06% / ° C.). In addition to compound systems, Hall elements made of Si can be used, and Hall ICs in which Hall elements and signal processing circuits such as operational amplifiers are integrated can be used. It is preferable to have a circuit configuration that reduces the offset voltage and has a temperature compensation function.

(Signal processing circuit)
The Hall element 3 is connected to a position signal processing circuit 9 including an operational amplifier, for example, as shown in FIG. 4 in order to output the position of the movable member as a voltage signal. In the present invention, a drive circuit (not shown) is connected to the input side terminal of the Hall element to drive the 4-terminal Hall element 3 to obtain an output voltage proportional to the magnetic flux density, and the Hall element output side A circuit configuration in which a differential amplifier circuit 92 is connected to the terminals can be employed. The Hall element is driven with a constant current or a constant voltage. However, when the GaAs Hall element is driven with a constant voltage, the temperature characteristics deteriorate (about −0.3% / ° C.). In the present invention, as shown in FIG. 4, on the input side of the Hall element 3, a constant current driving circuit 91 comprising an operational amplifier OP1 having a non-inverting input terminal connected to a power source (Vc = reference voltage) and a current limiting resistor R1 is provided. It can be connected and driven by a constant current operation where the control current Ic = Vc / R1.

In the differential amplifier circuit 92 that receives the output of the Hall element, the resistor R3 is connected to the operational amplifier OP2 connected to the negative feedback, the resistor R2 connected to the inverting input terminal of the operational amplifier OP2, and the non-inverting input terminal of the operational amplifier OP2. The output voltage of the Hall element is differentially amplified by the resistors R2 and R3. Since the gain G of this differential amplifier circuit is R3 / (R2 + Rout), the position information of the driven member can be output as an appropriate voltage signal by adjusting R2 and R3.

(Magnetic shield member)
Further, on the back side of each permanent magnet 7a, 7b (the magnetic pole surface on the side not facing the magnetic sensitive surface of the Hall element 3), the projected area (in FIG. 2, from the direction perpendicular to the magnetic pole surface of each magnet) A pair of flat yokes 8a and 8b made of a ferromagnetic material having a large area when viewed) are fixed. These flat yokes are magnetic shielding members provided to prevent the magnetic flux generated from the permanent magnets from leaking to the outside. The magnetic properties of the permanent magnets are similar to those of R-Fe-B based sintered magnets. It is effective when it is high. However, when the magnetic characteristics of the permanent magnet are low and the leakage magnetic flux is small, the magnetic shield member can be omitted.
[Operation of position detection device]

A position signal (amount of movement of the movable member) detected by the hall element 3 is amplified to a predetermined magnification by the signal processing circuit 9, and then compared with a target position command (coil position command signal) by a control circuit (not shown). A drive signal is generated, and a drive current is supplied to the drive circuit of the drive motor. Here, when the sensitivity center of the Hall element 3 exists at the initial position (the magnetic pole boundary position where the polarity is reversed), the output voltage of the Hall element is zero, but when the Hall element 3 moves in the Z direction, the output voltage of the Hall element 3 Changes in proportion to the magnetic flux density (increases or decreases linearly), so that the position of the movable member can be accurately detected. Here, in FIG. 1, when the movable member 5 moves in the Z direction and reaches the position where the arm 54 is locked to the fixed frame 41, the movable member 5 stops at that position. Is restricted, and can be prevented from falling off the fixed frame 41.

[Other embodiments]
In the present invention, when the movable range of the movable member is 2 mm or more and 5 mm or less, one of the detection magnet members shown in FIG. 3 can be omitted and the structure shown in FIG. 5 can be obtained. In FIG. 5, the detecting magnet member 6 disposed opposite to the Hall element 3 includes a flat permanent magnet 7 magnetized in the thickness direction, and a flat yoke 8 is fixed to the back side thereof. The gap gh2 between the magnetic pole surface and the Hall element 3 is arranged so as to increase or decrease linearly from one end to the other end. That is, the permanent magnet 7 is held by a movable member (not shown) so as to be inclined by an angle α3 with respect to a straight line parallel to the arrow Z1. Also with this structure, the position of the movable member can be accurately detected in a wider range than in the past for the same reason as in FIG.

[Experiment 1]
3, the magnetic flux density distribution in the Z direction when α1 = α2 = 30 ° and the gap gh1 (end portion side) between the Hall element 3 and the permanent magnets 7a and 7b is set to 1.5 mm is shown in FIG. Is shown by a solid line. This magnetic flux waveform uses an Nd-Fe-B sintered magnet (NMX-S45SH manufactured by Hitachi Metals, length = 8 mm, width = 2 mm, thickness = 1 mm) as a permanent magnet for detection. It is a simulation result at the time of using an element. The magnetic flux density distribution shown in FIG. 6 (the same applies to FIG. 7 described later) shows a waveform when the Hall element 3 moves from the initial position (magnet boundary) to the edge of the permanent magnet 7a or 7b. Since the magnetic flux density is substantially zero at the initial position, the offset of the output voltage is adjusted so that the output voltage of the Hall element becomes zero at this position.

  For comparison, as shown in FIG. 8, a detection magnet member 61 having a permanent magnet 71 a to which the yoke 81 a is fixed and a permanent magnet 71 b to which the yoke 81 b is fixed is arranged opposite to the Hall element 3, and The magnetic flux density distribution when the gap gh3 between the permanent magnets 71a and 71b and the Hall element 3 is maintained constant (1.5 mm) along the Z1 direction is shown by broken lines in FIG. However, the material and dimensions of the magnet member are the same as those described above.

As shown in FIG. 6, in the case of the present invention, the change of the magnetic flux density becomes linear in a very wide range (la1). On the other hand, when the gap gh3 between the Hall element and the end of the detection magnet is constant, the change in the magnetic flux density is linear only in the vicinity (lb) of the magnetic pole boundary, which is an extremely narrow range. It turns out that it becomes.

[Experiment 2]
5, the magnetic flux density distribution in the Z1 direction when the inclination α3 of the permanent magnet 7 is set to 30 ° and the gap gh2 (end portion side) between the Hall element 3 and the permanent magnet 7 is set to 1.5 mm is shown in FIG. Is shown by a solid line. This magnetic flux waveform is a simulation result in the case of using the same permanent magnet and GaAs Hall element as in Experimental Example 1. The magnetic flux density distribution shown in FIG. 7 shows a waveform when the Hall element 3 moves from the initial position (one end portion of the magnet) to the other end portion of the permanent magnet 7.

  For comparison, as shown in FIG. 9, a detection magnet member 62 having a permanent magnet 72 having a yoke 82 fixed on the back side is disposed opposite to the Hall element 3, and the permanent magnet 72 and the Hall element are arranged. The magnetic flux density distribution when the gap gh4 with respect to 3 is maintained constant (1.5 mm) along the Z1 direction is shown by a broken line in FIG. However, the material and dimensions of the magnet member are the same as those described above.

As shown in FIG. 7, in the case of the present invention, the change in the magnetic flux density is linear in a very wide range (la2). On the other hand, when the gap gh4 between the Hall element and the end of the detection magnet is constant, the magnetic flux density changes in a substantially sinusoidal shape, and the range in which the magnetic flux density changes linearly is only near the center of the magnetic pole. It turns out that it becomes very narrow range.

  In the above description, in order to reduce the weight of the movable part, the Hall element is provided on the movable frame and the detection magnet is provided on the fixed frame. However, the detection magnet is provided on the fixed frame and the Hall element is provided on the movable frame. The structure provided in may be sufficient. The position detection device of the present invention can be used for various applications including a device for driving a focus lens and a zoom lens.

1: position detection device,
2: wiring board, 21a, 21b: screw portion, 22a, 22b: positioning recess,
3: Hall element,
4: Fixed member, 41: Fixed frame, 410a, 410b: Leg part, 42: Space part, 43: Bottom plate part, 44: Sensor hole, 45: Projection part, 46a, 46b: Notch part, 47a, 47b: Guide shaft ,
5: Movable member, 51: Holding member, 52a: First slope, 52b: Second slope, 52c: Partition part, 53a, 53b: Slide part, 54: Arm part, 55: Projection part, 56a, 56b: Guide hole,
6, 6a, 6b: detection magnet member, 7a, 7b: permanent magnet, 8a, 8b: yoke,
9: signal processing circuit,
91: constant current circuit,
92: Amplifier circuit,

However, if a plurality of Hall elements are used as described in Patent Document 3, high detection accuracy can be obtained in a wide range, but the number of parts increases and the signal processing circuit becomes more complicated, resulting in increased costs. There is a problem. The position detection device described in Patent Document 4 has the following problems. As described in Patent Document 4 , in a structure in which a columnar detection magnet is covered with a yoke whose cross-sectional shape perpendicular to the longitudinal direction changes in the longitudinal direction, the number of parts increases and the cost increases, which causes a problem in practicality.

In the present invention, the magnet member for detection has a single permanent magnet magnetized in the thickness direction, and the gap facing the Hall element from one end to the other end in the moving direction is linear. The structure may be arranged so as to change.

Movement in order to achieve the above object, the position detecting device of the present invention comprises a single Hall element to be supported at a predetermined position of the fixing member by a predetermined distance with respect to the counter to and said fixed member to said Hall element In the position detection device having a detection magnet member installed on a movable member that is supported, the detection magnet member is magnetized in the thickness direction, and magnetic poles of different polarities are adjacent to each other along the movement direction , a pair of flat permanent magnets which have a rectangular cross section, and, together with the gap facing the Hall element toward the boundary of the magnets are arranged so as to increase, each permanent magnet, the Hall element The magnetically sensitive magnetic pole surface is inclined with respect to a straight line parallel to the magnetically sensitive surface by an angle range of 20 ° to 30 °, and each permanent magnet has an end portion on the side facing the other permanent magnet. A partition with a slope that touches It is installed in the holding member which has a part, It is characterized by the above-mentioned.

Claims (6)

In a position detection device having a Hall element supported at a predetermined position and a detection magnet member that is supported so as to be movable relative to the Hall element, the detection magnet member is magnetized in the thickness direction, A magnetic pole having a different polarity along the moving direction has a pair of permanent magnets adjacent to each other, and is arranged so that a gap facing the Hall element increases toward a boundary between both magnets. Position detector. In a position detection device having a Hall element supported at a predetermined position and a detection magnet member supported so as to be movable relative to the Hall element, the detection magnet member is magnetized in the thickness direction. A position detecting device having a single permanent magnet and arranged so that a gap facing the Hall element changes from one end to the other end in the moving direction.   3. The position detection according to claim 1, wherein a gap between the magnetic sensing surface of the Hall element and the detection magnet is set to 0.3 mm or more and 1.5 mm or less at the narrowest position. apparatus.   2. The detection magnet according to claim 1, wherein the magnetic sensing magnetic pole surface is inclined with respect to a straight line parallel to the magnetic sensing surface of the Hall element by an angle range of 20 ° to 30 °. 2. The position detection device according to 2.   The detection magnet is made of an R—Fe—B sintered magnet (where R is one or more of rare earth elements including Y and must contain Nd), and the detection magnetic pole surface of each of the detection magnets. The position detection device according to claim 1, wherein a magnetic shield member is attached to a magnetic pole surface opposite to the magnetic pole surface.   A fixed member on which a wiring board having a Hall element is fixed, and a movable member supported so as to be movable within a predetermined range with respect to the fixed member, and the movable member from one end side along the moving direction A position detection device comprising a pair of magnet members for detection installed so as to be inclined upward toward the other end side.

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