JP5373580B2 - Position detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a position detector capable of constituting a position detection duplexed system of one object to be detected, and being miniaturized. <P>SOLUTION: The position detector 1 includes a magnet 20 which moves along first to third movement lines y<SB>1</SB>, y<SB>2</SB>, x according to the operation of a shift lever 3, a first MR circuit 11 separated by d<SB>1</SB>with respect to the first movement line y<SB>1</SB>, a second MR circuit 12 arranged at an intermediate position between the first and second movement lines y<SB>1</SB>, y<SB>2</SB>, a third MR circuit 13 separated by d<SB>1</SB>at the opposite side to the first movement line y<SB>1</SB>with respect to the second movement line y<SB>2</SB>, and a position determination part 40. The position determination part 40 determines the position of the magnet 20 on the first movement line y<SB>1</SB>, on the basis of outputs of the first and second MR circuits 11, 12, and determines the position of the magnet 20 on the second movement line y<SB>2</SB>, on the basis of outputs of the second and third MR circuits 12, 13. Consequently, the position detection of the duplexed system can be performed by one magnet. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a position detection device.

  As conventional techniques, an MR (Magneto Resistance) element whose resistance value changes according to the strength of the magnetic field, a bias magnet that applies a constant magnetic field to these MR elements, and a shift lever that is a position detection target are connected. A position detection device as a shift lever unit including a magnetic body is known (see, for example, Patent Document 1).

  According to this conventional position detection device, the resistance of the MR element can be controlled by utilizing the property that the direction of the magnetic field is induced by the magnetic material when the magnetic material interlocked with the shift lever moves on the bias magnet. The position of the shift lever can be detected based on the amount of change.

JP 2009-204340 A

  In a position detection device as a shift lever unit mounted on a vehicle, it is necessary to avoid a function stop due to failure or malfunction of a sensor and a position detection circuit provided in the position detection device. For this purpose, it is effective that the position detection system of the position detection device is a double system. However, if the position detection system of the position detection device is a double system, at least two magnetic bodies that are positions to be detected are required, and it is necessary to increase the distance between them in order to prevent interference between the magnetic bodies. It has been difficult to downsize the position detection device.

  An object of the present invention is to provide a position detection device that can realize a double position detection system with a single detection target and can be miniaturized.

According to one aspect of the present invention, a magnetic field generator that is movable along first and second straight lines that are parallel to each other, and a first magnetic field generator that is provided at a position opposite to the second straight line with respect to the first straight line. One MR sensor, a second MR sensor provided between the first and second straight lines, and a third MR sensor provided at a position opposite to the first straight line with respect to the second straight line. And a fourth MR sensor provided apart from the first MR sensor in a direction parallel to the first straight line and having an output tilt characteristic opposite to that of the first MR sensor. , and a position detector for detecting the position of the magnetic field generator in the first and second straight line based on an output of the first through 4 MR sensor, the second MR sensor, four The MR element is inclined at 45 degrees with respect to the first and second straight lines. Providing position detecting device comprising a full bridge circuit connected Te.

  According to the present invention, a double position detection system can be realized by a single detection target and can be miniaturized.

FIG. 1 is a perspective view of a shift lever unit of a vehicle using a position detection device according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the shift position of the shift lever unit using the position detection device according to the embodiment of the present invention. FIG. 3 is a plan view of the position detection apparatus according to the embodiment of the present invention. FIG. 4A is a side view of the position detection apparatus according to the embodiment of the present invention, and FIG. 4B is a schematic diagram showing the direction of the magnetic flux on the substrate of the magnetic field generated by the magnet. FIG. 5 is a block diagram showing a circuit configuration of the position detection apparatus according to the embodiment of the present invention. FIG. 6A is a schematic diagram showing a pattern of a single MR element commonly used in the first to sixth MR circuits according to the embodiment of the present invention, and FIG. It is the schematic which shows the symbol of an element. FIG. 7A is a schematic diagram showing a pattern of the first MR circuit according to the embodiment of the present invention, and FIG. 7B is a schematic diagram showing the circuit with symbols. FIG. 8A is a schematic diagram showing a pattern of the second MR circuit according to the embodiment of the present invention, and FIG. 8B is a schematic diagram showing the circuit with symbols. FIG. 9A is a schematic diagram showing a pattern of a third MR circuit according to the embodiment of the present invention, and FIG. 9B is a schematic diagram showing the circuit with symbols. FIG. 10A is a schematic diagram showing a pattern of the fourth MR circuit according to the embodiment of the present invention, and FIG. 10B is a schematic diagram showing the circuit with symbols. FIG. 11A is a schematic diagram showing a pattern of a fifth MR circuit according to the embodiment of the present invention, and FIG. 11B is a schematic diagram showing the circuit with symbols. FIG. 12A is a schematic diagram showing a pattern of a sixth MR circuit according to the embodiment of the present invention, and FIG. 12B is a schematic diagram showing the circuit with symbols. FIG. 13 is a graph showing the relationship between the position of the magnet on the first movement line and the differential output. FIG. 14 is a graph showing the relationship between the position of the magnet on the second movement line and the differential output. FIG. 15 is a graph showing the relationship between the position of the magnet on the third movement line and the differential output.

[Embodiment]
(Configuration of shift lever unit)
FIG. 1 is a perspective view of a shift lever unit of a vehicle using a position detection device according to an embodiment of the present invention.

  The shift lever unit 2 includes, for example, a shift lever 3 for performing an operation of switching the shift position of the automatic transmission of the vehicle, a substantially H-shaped shift gate 4 into which the shift lever 3 is inserted, and the shift gate 4 Are formed, and a position detection device 1 for detecting the operation position of the shift lever 3 is provided. In the inner peripheral portion of the shift gate 4, for example, a guide groove 4 a that slides with a guided portion 3 a formed integrally with a part of the shaft of the shift lever 3 and guides the shift lever 3 to a predetermined shift position. Is provided.

FIG. 2 is a schematic diagram showing the shift position of the shift lever unit using the position detection device according to the embodiment of the present invention. In this shift lever unit 2, the shift lever 3 can be operated and moved to any one of the shift positions A to F shown in FIG. 2, for example. More specifically, for example, the shift positions A, B, and C are set stepwise along the first movement line y ₁ in order, and the second movement line y ₂ parallel to the _first movement line y _1. Shift positions D, E, and F are set along Further, the shift lever 3 is movable between the shift positions B and E, for example. That is, the shift positions B and E are set at positions where the third movement line x is orthogonal to the first and second movement lines y ₁ and y ₂ , respectively.

  Specifically, the shift positions A to F are, for example, shift position A is low drive (DL), shift position B is first neutral (N1), shift position C is parking (P), and shift position D is reverse. (R), the shift position E corresponds to the second neutral (N2), and the shift position F corresponds to the operation position of the drive (D). The position detection device 1 according to the present embodiment functions as a device that detects the position of the shift lever 3 in any one of these shift positions A to F.

(Configuration of position detection device)
FIG. 3 is a plan view of the position detection apparatus according to the embodiment of the present invention. The position detection apparatus 1 includes, for example, first to sixth MR circuits 11, 12, 13, 14, 15, 16 as MR (Magneto Resistance) sensors, and first to sixth MR circuits on a flat mounting surface. It includes a substrate 10 on which 11 to 16 are mounted, and a magnet 20 that is a detected object that is a direct target of position detection, and serves as a magnetic field generation unit.

For example, as shown in FIG. 3, the mounting surface (upper surface) of the substrate 10 has a positional relationship parallel to the virtual plane including the _first to third movement lines y ₁ , y ₂ , and x with a certain distance. is there.

  As will be described later, the first to sixth MR circuits 11 to 16 are configured as an MR sensor by forming a plurality of magnetoresistive elements (hereinafter referred to as “MR elements”) as bridge circuits. In the present embodiment, the magnetic field intensity generated by the magnet 20 is constant, and the attenuation of the magnetic field intensity received by the first to sixth MR circuits 11 to 16 is small enough to be ignored within the moving range of the magnet 20. And For this reason, the first to sixth MR circuits 11 to 16 in the present embodiment are also used as magnetic field direction detecting means for detecting the direction of the magnetic field.

  The first to sixth MR circuits 11 to 16 are mounted on the mounting surface of the substrate 10 in the form of, for example, an IC (Integrated Circuit) integrated on one chip, but a thin film is directly formed on the substrate 10. It may be formed.

Here, the distances d ₁ and d ₂ shown in FIG. 3 are, for example, parameters for design and production, and appropriate values are adopted according to specifications. In the present embodiment, for example, the distance d ₁ is ½ of the distance between the first movement line y ₁ and the second movement line y ₂ , and the distance d ₂ is between the shift positions A and C. 1/2 of the distance.

For example, the first MR circuit 11 is disposed on a line that is separated from the first movement line y ₁ by a distance d ₁ , passes through the center of the shift position A, and is orthogonal to the _first movement line y _1. Yes.

The second MR circuit 12 is separated from the first movement line y ₁ by the same distance d ₁ at the same symmetric position as the first MR circuit 11 and to the second movement line y ₂ . They are spaced apart also by a distance d _1.

The third MR circuit 13 is disposed on a line that is separated from the second movement line y ₂ by a distance d ₁ , passes through the center of the shift position D, and is orthogonal to the _second movement line y ₂ .

The fourth MR circuit 14 is disposed on a line that is separated from the first movement line y ₁ by a distance d ₁ , passes through the center of the shift position C, and is orthogonal to the _first movement line y ₁ . That is, the fourth MR circuit 14 and the first MR circuit 11 are separated by a distance twice as long as the distance d _{2 in} the direction parallel to the _first movement line y ₁ .

The fifth MR circuit 15 is separated from the first movement line y ₁ by the same distance d ₁ at the same symmetric position as the fourth MR circuit 14 and to the second movement line y ₂ . They are spaced apart also by a distance d _1. That is, the fifth MR circuit 16 and the second MR circuit 12 are separated by a distance twice as long as the distance d _{2 in} the direction parallel to the first movement line y ₁ and the second movement line y _2. Yes.

The sixth MR circuit 16 is disposed on a line that is separated from the second movement line y ₂ by a distance d ₁ , passes through the center of the shift position F, and is orthogonal to the _second movement line y ₂ . That is, the sixth MR circuit 16 and the third MR circuit 13 are separated from each other by a distance twice the distance d _{2 in} the direction parallel to the _second movement line y ₂ .

  FIG. 4A is a side view of the position detection device according to the embodiment of the present invention, and FIG. 4B is a schematic diagram showing the direction of the magnetic flux MF on the substrate of the magnetic field generated by the magnet. .

As shown in FIG. 4A, the magnet 20 is made of a permanent magnet formed in a disk shape, and is magnetized so that the magnetic poles of S and N are on the upper and lower circular plane sides. The surface of one magnetic pole (for example, S pole) of the magnet 20 is fixed to the lower part of the guided portion 3a of the shift lever 3 and moves on the movement lines y ₁ , y ₂ , x as the shift lever 3 is operated. It is provided as follows. The magnet 20 is not limited to a permanent magnet, and may be an electromagnet. Further, the shape of the magnet 20 is not limited to a disk shape as long as the magnetic flux is emitted radially, and may be, for example, a square shape, a polygonal shape, or a rectangular shape.

  Accordingly, the magnetic flux MF on the mounting surface of the substrate 10 is emitted radially and uniformly around the magnet 20 as shown in FIG. 4B, for example. Note that the magnet 20 may be fixed in reverse to the present embodiment (eg, the N pole is on the guided portion 3a side). This is because the directionality of the magnetic field from the magnet 20 does not affect the operation characteristics of position detection by the first to sixth MR circuits 11 to 16 at all.

(Circuit configuration of position detection device)
FIG. 5 is a block diagram showing a circuit configuration of the position detection apparatus according to the embodiment of the present invention. FIG. 6A is a schematic diagram showing a pattern of a single MR element commonly used in the first to sixth MR circuits according to the embodiment of the present invention, and FIG. It is the schematic which shows the symbol of the MR element.

The MR element 100 is formed of a thin film mainly composed of a ferromagnetic material such as NiFe permalloy, NiCo, and FeCo alloy, for example. As shown in FIG. 6A, the MR element 100 has a plurality of magnetically sensitive portions 101 that are long in the same direction and meandering with a linear ferromagnetic thin film pattern connected by a plurality of folded portions. It is configured. In the MR element 100 having such a pattern shape, the magnetic sensing portion 101 is overwhelmingly dominant in the portion that contributes to the detection of the magnetic field strength compared to the folded portion. For this reason, in this specification, the longitudinal direction of the plurality of magnetic sensing portions 101 indicated by the arrow I is defined as the “current direction” of the MR element. When attention is paid to the relationship between the two magnetic sensing portions 101 and 101 adjacent to each other, the directions in which the current flows are opposite to each other, but the “current direction” herein includes the directions of both currents. Used. Further, the current direction of the MR element 100 in FIG. 6A is assumed to be parallel to the first and second movement lines y ₁ and y ₂ , for example.

  5-12, the MR element of FIG. 6A is replaced with the box-shaped symbol shown in FIG. 6B, and the current direction is made to coincide with the longitudinal direction of the symbol. Shall be shown.

In the MR element 100, when a constant magnetic field (H) is supplied between the terminals 102 and 103 and a magnetic field (H) in a range that does not saturate is given at an angle θ with respect to the direction orthogonal to the current direction I, the magnetic field strength is increased. The electric resistance decreases in proportion to the square of the cosine component of (| H | cos ² θ).

FIG. 7A is a schematic diagram showing a pattern of the first MR circuit according to the embodiment of the present invention, and FIG. 7B is a schematic diagram showing the circuit with symbols. First MR circuits 11 is composed of, for example, two MR elements 111 and 112 to each other of the current directions are orthogonal are connected in series, the mobile lines _{y 1} of one of the MR element 111 is first, FIG. inclination MR element 100 shown in 6 (a) to 45 degrees counter-clockwise as a reference with respect to the other MR element 112 first movement line _{y 1,} based on the MR element 100 shown in FIG. 6 (a) It is tilted 45 degrees clockwise. In the following description, when using clockwise and counterclockwise expressions, the MR element 100 shown in FIG. 6A is used as a reference unless otherwise specified.

As described above, the first MR circuit 11 formed of a half bridge is disposed so as to be separated from the first movement line y ₁ by a distance d ₁ . Here, the distance _{d 1} from the first mobile line _{y 1,} the magnetic sensitive sections 101 connecting the two MR elements 111 and 112 which constitute the half bridge midpoint a first of the moving line _{y 1} The distance between them. The same applies to the third, fourth, and sixth MR circuits 11, 14, and 16 formed of half bridges.

In the first MR circuit 11, as shown in FIGS. 7A and 7B, a constant voltage Vs is supplied to the terminal 113 of the MR element 111, and GND (ground) is connected to the terminal 114 of the MR element 112. It is composed of a half-bridge circuit. Then, the divided bridge output V ₁ is outputted from the terminal 115.

  FIG. 8A is a schematic diagram showing a pattern of the second MR circuit according to the embodiment of the present invention, and FIG. 8B is a schematic diagram showing the circuit with symbols. In the second MR circuit 12, four MR elements 121, 122, 123, 124 are connected in a ring shape with their current directions orthogonal to each other. MR element 121 tilts 45 degrees clockwise, MR element 122 tilts 45 degrees counterclockwise, MR element 123 tilts 45 degrees counterclockwise, and MR element 124 tilts 45 degrees clockwise. Be placed.

As described above, the second MR circuit 12 composed of a full bridge is separated from the first movement line y _{1 by the} distance d _{1 and is} also separated from the second movement line y ₂ by the distance d _1. Are arranged. Regarding the full bridge MR circuit shown below, the distance d ₁ from the first or second movement line y ₁ , y ₂ is the center of gravity of the four MR elements 121, 122, 123, and 124 constituting the full bridge. This refers to the distance between the first or second movement line y ₁ and y ₂ . The same applies to the fifth MR circuit 15 composed of a full bridge.

As shown in FIGS. 8A and 8B, the second MR circuit 12 is supplied with a constant voltage Vs to a terminal 125 to which the MR element 121 and the MR element 123 are connected, and the MR element 122 and the MR element 124. Is configured by a full bridge circuit in which GND is connected to a terminal 126 to which is connected. The divided bridge outputs V ₂₁ and V ₂₂ are outputted from terminals 127 and 128, respectively.

FIG. 9A is a schematic diagram showing a pattern of a third MR circuit according to the embodiment of the present invention, and FIG. 9B is a schematic diagram showing the circuit with symbols. As shown in FIGS. 9A and 9B, the third MR circuit 13 includes two MR elements 131 and 132 whose current directions are orthogonal to each other and connected in series. The MR element 132 is inclined 45 degrees clockwise and the other MR element 132 is inclined 45 degrees counterclockwise. The third MR circuit 13 is configured by a half bridge circuit in which a constant voltage Vs is supplied to the terminal 133 of the MR element 131 and GND is connected to the terminal 134 of the MR element 132. Then, the divided bridge output V ₃ is output from the terminal 135.

FIG. 10A is a schematic diagram showing a pattern of the fourth MR circuit according to the embodiment of the present invention, and FIG. 10B is a schematic diagram showing the circuit with symbols. As shown in FIGS. 10A and 10B, the fourth MR circuit 14 includes two MR elements 141 and 142 whose current directions are orthogonal to each other and connected in series. The MR element 142 is tilted 45 degrees clockwise and the other MR element 142 is tilted 45 degrees counterclockwise. The fourth MR circuit 14 is configured by a half-bridge circuit in which a constant voltage Vs is supplied to the terminal 143 of the MR element 141 and GND is connected to the terminal 144 of the MR element 142. The divided bridge output V ₄ is output from the terminal 145.

Here, the first MR circuit 11 and the fourth MR circuit 14 have the slope characteristics of the bridge outputs opposite to each other. That is, the first MR circuits 11, whereas the direction of the magnetic field incident is increased bridge output V ₁ as in the counterclockwise direction (shift position A side) with respect to the horizontal, the fourth MR circuit 14 The bridge output V ₄ increases as the direction of the incident magnetic field is clockwise (shift position C side) with respect to the horizontal. In addition, horizontal is a direction parallel to the third movement line x.

  FIG. 11A is a schematic diagram showing a pattern of a fifth MR circuit according to the embodiment of the present invention, and FIG. 11B is a schematic diagram showing the circuit with symbols. In the fifth MR circuit 15, as shown in FIGS. 11A and 11B, four MR elements 151, 152, 153, and 154 are annularly connected with their current directions orthogonal to each other. MR element 151 tilts 45 degrees clockwise, MR element 152 tilts 45 degrees counterclockwise, MR element 153 tilts 45 degrees counterclockwise, and MR element 154 tilts 45 degrees clockwise. Be placed.

In the fifth MR circuit 15, the constant voltage Vs is supplied to the terminal 155 to which the MR element 151 and the MR element 153 are connected, and the GND is connected to the terminal 156 to which the MR element 152 and the MR element 156 are connected. Consists of a full bridge circuit. The divided bridge outputs V ₅₁ and V ₅₂ are output from terminals 157 and 158, respectively.

FIG. 12A is a schematic diagram showing a pattern of a sixth MR circuit according to the embodiment of the present invention, and FIG. 12B is a schematic diagram showing the circuit with symbols. As shown in FIGS. 12A and 12B, the sixth MR circuit 16 is formed by connecting two MR elements 161 and 162 whose current directions are orthogonal to each other in series. The MR element 162 is inclined 45 degrees counterclockwise and the other MR element 162 is inclined 45 degrees clockwise. The sixth MR circuit 16 is configured by a half bridge circuit in which a constant voltage Vs is supplied to the terminal 163 of the MR element 161 and GND is connected to the terminal 164 of the MR element 162. Then, the divided bridge output V ₆ is outputted from the terminal 165.

Here, the third MR circuit 13 and the sixth MR circuit 16 have opposite bridge output slope characteristics. That is, the third MR circuit 13, while the direction of the magnetic field incident is increased bridge output V ₃ as in the clockwise direction (shift position D side) with respect to the horizontal, MR circuit 16 of the sixth The bridge output V ₆ increases as the direction of the incident magnetic field is counterclockwise with respect to the horizontal (shift position F side).

As shown in FIG. 5, the position detection device 1 further includes a first differential amplifier 31 that arithmetically amplifies the voltage difference between the bridge outputs V ₁ and V ₄ of the first and fourth MR circuits 11 and 14, and The second differential amplifier 32 for calculating and amplifying the voltage difference between the bridge outputs V ₂₁ and V ₅₂ of the second and fifth MR circuits 12 and 15, and the bridge output V of the second and fifth MR circuits 12 and 15. ₂₂ , V ₅₁ , the third differential amplifier 33 for calculating and amplifying the voltage difference, and the fourth difference for calculating and amplifying the voltage difference between the bridge outputs V ₃ , V ₆ of the third and sixth MR circuits 13, 16. Of the dynamic amplifier 34, the fifth differential amplifier 35 for calculating and amplifying the voltage difference between the bridge outputs V ₂₁ and V ₂₂ of the second MR circuit 12, and the bridge outputs V ₅₁ and V ₅₂ of the fifth MR circuit 15. And a sixth differential amplifier 36 for calculating and amplifying the voltage difference. That.

Further, the position detection device 1 is provided with a position determination unit 40 as a position detection unit for inputting the outputs V _{31 to} V ₃₆ of the first to sixth differential amplifiers _{31 to 36} . The position determination unit 40 includes a CPU (Central Processing Unit), a memory, an AD (Analog Digital) conversion unit, an in-vehicle LAN (Local Area Network) control unit, and the like (not shown), and the CPU according to a program stored in the memory. Is configured by an MPU (Micro Processing Unit) that performs arithmetic operations. The position determination unit 40 transmits a function for determining the position (shift position) of the magnet 20 based on the outputs V _{31 to} V ₃₆ and position detection data to an ECU (Electronic Control Unit) of the vehicle (not shown) as needed. It has a function.

  Hereinafter, the operation of the position detection apparatus according to the present embodiment will be described in detail with reference to the drawings.

(Operation)
The magnet 20 connected to the lower part of the shift lever 3 moves along the _first to third movement lines y ₁ , y ₂ , x shown in FIGS. 3 and 5 according to the operation of the shift lever 3 by the user. .

In the first MR circuit 11, for example, when the MR element 111 receives a magnetic field having an incident angle θ ₁₁ with respect to a direction orthogonal to the current direction from the magnet 20 moving on the first movement line y ₁ , The resistance value R ₁₁₁ decreases to the value shown in Equation (1).
R ₁₁₁ = R ₀ −ΔR cos ² (θ ₁₁ −45 °) Formula (1)
Here, R ₀ is an initial resistance value, and ΔR is a resistance change rate.

On the other hand, when the MR element 112 receives, for example, a magnetic field having the same intensity at the same incident angle θ ₁₁ , the electrical resistance value R ₁₁₂ decreases to the value shown in Equation (2).
R ₁₁₂ = R ₀ −ΔR cos ² (θ ₁₁ + 45 °) Formula (2)

Therefore, the bridge output V ₁ of the first MR circuit 11 can be expressed by, for example, Expression (3).
V ₁ = [{R ₀ −ΔR cos ² (θ ₁₁ + 45 °)} / {2R ₀ −ΔR}] × Vs Formula (3)

On the other hand, as for the second MR circuit 12, for example, at the position of the magnet 20 of the same first on moving line _{y 1} and the bridge output _{V 21} based on the magnetic field of the incident angle theta ₁₂ from the magnet 20, the formula It is represented by (4).

V ₂₁ = [{R ₀ −ΔR cos ² (θ ₁₂ + 45 °)} / {2R ₀ −ΔR}] × Vs Formula (4)

Regarding the fourth MR circuit 14, for example, the bridge output V ₄ based on the magnetic field of the incident angle θ ₁₄ from the magnet 20 at the position of the magnet 20 on the same first movement line y ₁ as described above is expressed by the following equation. It is represented by (5).
V ₄ = [{R ₀ −ΔR cos ² (θ ₁₄ −45 °)} / {2R ₀ −ΔR}] × Vs Formula (5)

Furthermore, for the fifth MR circuit 15, for example, the bridge output V ₅₂ based on the magnetic field of the incident angle θ ₁₅ from the magnet 20 at the position of the magnet 20 on the same first movement line y ₁ as described above is It is expressed by Equation (6).
V ₅₂ = [{R ₀ −ΔR cos ² (θ ₁₅ −45 °)} / {2R ₀ −ΔR}] × Vs Formula (6)

FIG. 13 shows the positions of the magnets on the _first movement line y ₁ and the differential outputs V ₃₁ (= V ₁ −V ₄ ), V ₃₂ (= V ₂₁ −V) based on the equations (3) to (6). ₅₂ ). In FIG. 13, the horizontal axis is the position of the magnet 20, and the position corresponding to the shift position B is the origin. In the graph shown in FIG. 13, for example, the distance d ₁ and the distance d ₂ are the same (d ₁ = d ₂ ), the maximum resistance change rate is 2% (ΔR / R ₀ = 0.02), and the constant voltage Vs Is obtained by calculating the value of 5V and the amplification factor of the differential amplifiers 31 and 32 as 1.

If the coordinate position of the magnet 20 on the _first movement line y ₁ is y, the aforementioned incident angles θ ₁₁ , θ ₁₂ , θ ₁₄ , and θ ₁₅ are expressed by, for example, equations (7) to (10). Is done.
θ ₁₁ = tan ⁻¹ {(y−d ₂ ) / d ₁ } Formula (7)
θ ₁₂ = tan ⁻¹ {(y−d ₂ ) / d ₁ } Formula (8)
θ ₁₄ = tan ⁻¹ {(y + d ₂ ) / d ₁ } Formula (9)
θ ₁₅ = tan ⁻¹ {(y + d ₂ ) / d ₁ } Formula (10)

As illustrated in FIG. 13, for example, by setting the threshold value Vt ₁ to 12 mV and the threshold value Vt ₂ to −12 mV, the position determination unit 40 outputs the outputs V ₃₁ and V _{32 of the} differential amplifiers ₃₁ and _32. Based on at least one of the above, it is determined which of the positions corresponding to the shift positions A, B, and C the magnet 20 is.

In the present embodiment, the phase difference between the incident angles θ ₁₁ and θ ₁₄ of the magnetic fields incident on the first MR circuit 11 and the fourth MR circuit 14 is approximately as shown in equations (7) and (9). Although it is 90 °, it is not always constant. However, if the phase difference is always 90 °, the differential output of the MR circuit shown in FIG. 13 can be approximated to a straight line.

Next, for the magnetic field from the magnet 20 on the _second movement line y ₂ , the bridge outputs V _{22 of} the second, third, fifth, and sixth MR circuits 12, 13, 15, and 16, V ₃ , V ₅₁ , and V ₆ are represented by, for example, formulas (11) to (14), respectively.
V ₂₂ = [{R ₀ −ΔR cos ² (θ ₂₂ + 45 °)} / {2R ₀ −ΔR}] × Vs Formula (11)
V ₃ = [{R ₀ −ΔR cos ² (θ ₂₃ + 45 °)} / {2R ₀ −ΔR}] × Vs Formula (12)
V ₅₁ = [{R ₀ −ΔR cos ² (θ ₂₅ −45 °)} / {2R ₀ −ΔR}] × Vs Formula (13)
V ₆ = [{R ₀ −ΔR cos ² (θ ₂₆ −45 °)} / {2R ₀ −ΔR}] × Vs Formula (14)

FIG. 14 shows the positions of the magnets on the _second movement line y ₂ and the differential outputs V ₃₃ (= V ₂₂ −V ₅₁ ) and V ₃₄ (= V ₃ −V) based on the equations (11) to (14). ₆ ) is a graph showing the relationship with ( ₆ ). In FIG. 14, the horizontal axis is the position of the magnet 20, and the position corresponding to the shift position E is the origin. Further, in the graph shown in FIG. 14, for example, as in FIG. 13, the distance d ₁ and the distance d ₂ are the same (d ₁ = d ₂ ), and the maximum resistance change rate is 2% (ΔR / R ₀ = 0. 02), the value of the constant voltage Vs is 5V, and the amplification factor of the differential amplifiers 33 and 34 is 1. Further, in the equations (11) to (14), the incident angle of the magnetic field incident on the second MR circuit 12 from the position of the magnet 20 on the _second movement line y ₂ is θ ₂₂ , and the third MR circuit 13 is input. The incident angle of the incident magnetic field is θ ₂₃ , the incident angle of the magnetic field incident on the fifth MR circuit 15 is θ ₂₅ , and the incident angle of the magnetic field incident on the sixth MR circuit 16 is θ ₂₆ .

As shown in FIG. 14, for example, by setting the threshold value Vt ₃ to 12 mV and the threshold value Vt ₄ to −12 mV, the position determination unit 40 outputs the outputs V ₃₃ and V _{34 of the} differential amplifiers ₃₃ and _34. Based on at least one of these, it is determined which of the positions corresponding to the shift positions D, E, and F the magnet 20 is.

Further, for the magnetic field from the magnet 20 on the third movement line x, the bridge outputs V ₂₁ , V ₂₂ , V ₅₁ , V ₅₂ of the second and fifth MR circuits 12, 15 are, for example, Respectively, they are represented by mathematical formulas (15) to (18).
V ₂₁ = [{R ₀ −ΔR cos ² (θ ₃₂ + 45 °)} / {2R ₀ −ΔR}] × Vs Formula (15)
V ₂₂ = [{R ₀ −ΔR cos ² (θ ₃₂ −45 °)} / {2R ₀ −ΔR}] × Vs Formula (16)
V ₅₁ = [{R ₀ −ΔR cos ² (θ ₃₅ −45 °)} / {2R ₀ −ΔR}] × Vs Formula (17)
V ₅₂ = [{R ₀ −ΔR cos ² (θ ₃₅ + 45 °)} / {2R ₀ −ΔR}] × Vs Formula (18)

FIG. 15 shows the positions of the magnets on the third movement line x and the differential outputs V ₃₅ (= V ₂₁ −V ₂₂ ) and V ₃₆ (= V ₅₂ −V ₅₁ ) based on the equations (15) to (18). ). In FIG. 15, the horizontal axis is the position of the magnet 20, and the equidistant position is the origin between the positions corresponding to the shift positions B and E. In the graph shown in FIG. 15, for example, as in FIG. 13, the distance d ₁ and the distance d ₂ are the same (d ₁ = d ₂ ), and the maximum resistance change rate is 2% (ΔR / R ₀ = 0. 02), the value of the constant voltage Vs is 5V, and the amplification factors of the differential amplifiers 35 and 36 are calculated as 1. Further, in Equations (15) to (18), the incident angle of the magnetic field incident on the second MR circuit 12 from the position of the magnet 20 on the third movement line x is θ ₃₂ , and incident on the fifth MR circuit 15. the incident angle of the magnetic field is set to θ _35.

As shown in FIG. 15, for example, by setting the threshold value Vt ₅ to 0 V, the position determination unit 40 is based on at least one of the outputs V ₃₅ and V ₃₆ of the differential amplifiers ₃₅ and ₃₆ . It is determined whether the magnet 20 is in a position corresponding to the shift position B or E.

For example, when the position determination unit 40 determines that the outputs V ₃₅ and V ₃₆ are negative values (<Vt ₅ (= 0 V)) and the magnet 20 is on the first movement line y ₁ , The position detection of the shift positions A, B, and C based on the outputs V ₃₁ and V ₃₂ of the amplifiers 31 and ₃₂ is made effective. For example, when the position determination unit 40 determines that the outputs V ₃₅ and V ₃₆ are positive values (> Vt ₅ (= 0 V)) and the magnet 20 is on the second movement line y ₂ , The position detection of the shift positions D, E, and F based on the outputs V ₃₃ and V ₃₄ of the differential amplifiers 33 and ₃₄ is made effective.

(effect)
According to the position detection device 1 according to the present embodiment, the position determination unit 40 is configured such that the magnet 20 has the first movement line based on at least one of the outputs V ₃₁ and V ₃₂ of the differential amplifiers ₃₁ and _32. shift position a is set to y _1, B, it can be determined whether there in any position of the C. That is, the detection system of the first and fourth MR circuits 11 and 14 serving as the basis of the output V ₃₁ and the detection system of the second and fifth MR circuits 12 and 15 serving as the basis of the output V ₃₂ are doubled. The position of the magnet 20 on the _first movement line y1 can be detected by the system. For this reason, even if a failure or failure occurs in one detection system, the other detection system can function as a backup.

Similarly, when detecting the position of the second on the moving line _{y 2,} the position determining section 40, based on at least one of the output _{V 33, V 34} of the differential amplifier 33, the shift position It can be determined which position is D, E, or F. Further, the second and fifth MR circuits 12 and 15 which are the basis of the output V ₃₃ are configured by a full bridge circuit, and thus are common to the position detection system on the _first movement line y ₁ described above. Used. For this reason, the number of MR circuits can be reduced as compared with the case where the two detection systems are constituted by half bridges.

When detecting the position on the third movement line x, the position determination unit 40 determines the position of the shift position B or E based not only on the outputs V ₃₅ and V ₃₆ but also on the outputs V ₃₁ and V _34. Can be determined. That is, as a result, a multiplex (quadruple) detection system is configured for the movement line x. The first to sixth MR circuits 11 to 16 serving as the basis of these outputs V ₃₅ and V ₃₆ and outputs V ₃₁ and V ₃₄ detect positions on the first and second movement lines y ₁ and y _2. It is also used in common with the detection system. Therefore, the detection system can be multiplexed without adding an MR circuit, and the apparatus can be easily downsized.

  Furthermore, according to the position detection device 1 according to the present embodiment, it is possible to realize a double position detection using only one magnet 20 as a magnetic field generation unit, and a case where two magnetic field generation units are used. In comparison, the problem of mutual interference of magnetic fields does not occur, and the apparatus can be easily downsized. Furthermore, the number of magnets 20 can be reduced to contribute to cost reduction.

  The present invention is not limited to the above-described embodiments, and various modifications and combinations can be made without departing from or changing the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Position detection apparatus, 2 ... Shift lever unit, 3 ... Shift lever, 3a ... Guide part, 4 ... Shift gate, 4a ... Guide groove, 5 ... Panel, 10 ... Board | substrate, 11 ... 1st MR circuit, 12 2nd MR circuit, 13 ... 3rd MR circuit, 14 ... 4th MR circuit, 15 ... 5th MR circuit, 16 ... 6th MR circuit, 20 ... Magnet, 31, 32, 33, 34 , 35, 36 ... differential amplifier, 40 ... position determination unit, 100 ... MR element, 101 ... magnetic sensing part, 102, 103 ... terminal, 111, 112 ... MR element, 113, 114 ... terminal, 121, 122, 123 124, MR element, 125, 126, 127, 128 ... terminal, 131, 132 ... MR element, 133, 134 ... terminal, 141, 142 ... MR element, 143, 144 ... terminal, 151, 152, 153, 154 ... MR Child, 155,156,157,158 ... terminal, A, B, C, D , E, F ... shift position, H ... magnetic field vector, I ... current direction, MF ... flux, R 0 _... initial resistance value, [Delta] R ... Resistance change rate, d ₁ , d ₂ ... distance, y ₁ ... first movement line, y ₂ ... second movement line, x ... third movement line, V ₁ , V ₂₁ , V ₂₂ , V ₃ , V ₄ , V ₅₁ , V ₅₂ ... bridge output, V ₃₁ , V ₃₂ , V ₃₃ , V ₃₄ , V ₃₅ , V ₃₆ ... output, Vs ... constant voltage, Vt ₁ , Vt ₂ , Vt ₃ , Vt ₄ , Vt ₅ : Threshold value, θ: Incident angle of magnetic field

Claims (5)

A magnetic field generator movable along first and second straight lines parallel to each other;
A first MR sensor provided at a position opposite to the second straight line with respect to the first straight line;
A second MR sensor provided between the first and second straight lines;
A third MR sensor provided at a position opposite to the first straight line with respect to the second straight line;
A fourth MR sensor provided apart from the first MR sensor in a direction parallel to the first straight line and having an output tilt characteristic opposite to that of the first MR sensor;
A position detection unit that detects a position of the magnetic field generation unit in the first and second straight lines based on outputs of the first to fourth MR sensors,
The second MR sensor is a position detection device comprising a full bridge circuit in which four MR elements are connected with their current directions inclined at 45 degrees with respect to the first and second straight lines. The full MR sensor is provided apart from the second MR sensor in a direction parallel to the first straight line, and four MR elements are connected with their current directions inclined at 45 degrees with respect to the first and second straight lines. A fifth MR sensor comprising a bridge circuit;
A sixth MR sensor provided apart from the third MR sensor in a direction parallel to the second straight line and having an output tilt characteristic opposite to that of the third MR sensor;
The position detection apparatus according to claim 1 . The position detection unit is configured to output the magnetic field generation unit in the first straight line based on at least one of the outputs of the first and fourth MR sensors or the outputs of the second and fifth MR sensors. The position detection device according to claim 2 which detects a position. The position detector is configured to output the magnetic field generator in the second straight line based on at least one output of the outputs of the second and fifth MR sensors or the outputs of the third and sixth MR sensors. The position detection device according to claim 3 which detects a position. The magnetic field generation unit is movable along the first and second straight lines, and is movable along a third straight line orthogonal to the first and second straight lines,
The position detection unit according to claim 4 , wherein the position detection unit detects a position of the magnetic field generation unit in the third straight line based on an output of the second MR sensor or an output of the fifth MR sensor. apparatus.

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