JP5373581B2 - 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 immediately below the first movement line y<SB>1</SB>, a third MR circuit 13 arranged immediately below the second movement line y<SB>2</SB>, a fourth MR circuit 14 separated by d<SB>1</SB>at the opposite side to the second MR circuit 12 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 the outputs of the first and third MR circuits 11, 13, and determines the position of the magnet 20 on the second movement line y<SB>2</SB>, on the basis of the outputs of the second and fourth MR circuits 12, 14. 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. 1 MR sensor, a second MR sensor provided on the same side as the first MR sensor with respect to the second straight line, and the first MR sensor with respect to the first straight line A third MR sensor provided at an opposite position, a fourth MR sensor provided at a position opposite to the second MR sensor with respect to the second straight line, and parallel to the first straight line. And a first MR sensor that is spaced apart from the first MR sensor and has an output tilt characteristic opposite to that of the first MR sensor, and outputs of the first to fifth MR sensors. The position of the magnetic field generator in the first and second straight lines based on A second position sensor, and the second MR sensor is disposed between the first and third MR sensors, and the third MR sensor is formed of the second and fourth MR sensors. Provided is a position detection device disposed between the two.

  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. 13A is a schematic diagram showing a pattern of a seventh MR circuit according to the embodiment of the present invention, and FIG. 13B is a schematic diagram showing the circuit with symbols. FIG. 14A is a schematic diagram showing a pattern of an eighth MR circuit according to the embodiment of the present invention, and FIG. 14B is a schematic diagram showing the circuit with symbols. FIG. 15 is a graph showing the relationship between the position of the magnet on the first movement line and the differential output. FIG. 16 is a graph showing the relationship between the position of the magnet on the second movement line and the differential output. FIG. 17 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 device 1 includes, for example, first to eighth MR circuits 11, 12, 13, 14, 15, 16, 17, 18 as MR (Magneto Resistance) sensors, and first to first MR circuits on a flat mounting surface. 8 MR circuits 11 to 18 and a magnet 20 as a magnetic field generator, which is a detected object that is a direct target of position detection.

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 eighth MR circuits 11 to 18 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 eighth MR circuits 11 to 18 is small enough to be ignored within the moving range of the magnet 20. And Therefore, the first to eighth MR circuits 11 to 18 in the present embodiment are also used as magnetic field direction detection means for detecting the direction of the magnetic field.

  The first to eighth MR circuits 11 to 18 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 the same as the distance between the first movement line y ₁ and the second movement line y ₂ , and the distance d ₂ is the distance between the shift positions A and C. Are the same.

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 disposed on a line corresponding to the center of the shift position A on a line obtained by projecting the first movement line y ₁ onto the mounting surface of the substrate 10 immediately below the _first movement line y ₁ .

The third MR circuit 13 is arranged on a line corresponding to the center of the shift position D on the line obtained by projecting the second movement line y2 onto the mounting surface of the substrate 10 immediately below the _second movement line y2.

The fourth MR circuit 14 is arranged at the same symmetric position on the same line as the second MR circuit 12 with respect to the second movement line y ₂ and separated by the same distance d ₁ .

The fifth MR circuit 15 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 fifth MR circuit 15, in a direction parallel to the first mobile line _{y 1,} is spaced apart from the first MR circuits 11 by a distance _{d 2.}

The sixth MR circuit 16 is disposed on a line corresponding to the center of the shift position C on a line obtained by projecting the first movement line y1 onto the mounting surface of the substrate 10 immediately below the _first movement line y1. That is, the sixth MR circuit 16 is arranged at a distance d ₂ from the second MR circuit 12 in the direction parallel to the _first movement line y ₁ .

The seventh MR circuit 17 is disposed on a line corresponding to the center of the shift position F on the line obtained by projecting the second movement line y2 onto the mounting surface of the substrate 10 immediately below the _second movement line y2. That is, the seventh MR circuit 17 is arranged at a distance d ₂ from the third MR circuit 13 in the direction parallel to the _second movement line y ₂ .

The eighth MR circuit 18 is arranged at the same symmetric position on the same line as the sixth MR circuit 16 with respect to the _second movement line y ₂ and separated by the same distance d ₁ . That is, the eighth MR circuit 18 is arranged at a distance d ₂ from the fourth MR circuit 14 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.

  5-14, the MR element in 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 11 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 fourth, fifth and eighth MR circuits 14, 15 and 18.

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, two MR elements 121 and 122 whose current directions are orthogonal to each other are connected in series, one MR element 121 tilts 45 degrees counterclockwise, and the other MR element 122 It is tilted 45 degrees clockwise.

As described above, the second MR circuit 12 formed of a half bridge is disposed on a line obtained by projecting the first movement line y1 onto the mounting surface of the substrate 10 immediately below the _first movement line y1. In other words, the midpoint of the magnetic sensitive sections connecting the two MR elements 121 and 122 which constitute the half-bridge is located on the first immediately below the line of travel y _1. The same applies to the third, sixth, and seventh MR circuits 13, 16, and 17.

As shown in FIGS. 8A and 8B, the second MR circuit 12 is a half bridge in which a constant voltage Vs is supplied to the terminal 123 of the MR element 121 and GND is connected to the terminal 124 of the MR element 122. Consists of a circuit. The divided bridge output V ₂ is output from the terminal 125.

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 outputted 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.

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. As shown in FIGS. 11A and 11B, the fifth MR circuit 15 includes two MR elements 151 and 152 whose current directions are orthogonal to each other and connected in series. The other MR element 152 is tilted 45 degrees clockwise and the other MR element 152 is tilted 45 degrees counterclockwise. The fifth MR circuit 15 is configured by a half bridge circuit in which a constant voltage Vs is supplied to the terminal 153 of the MR element 151 and GND is connected to the terminal 154 of the MR element 152. Then, the divided bridge output V ₅ is outputted from the terminal 155.

Here, the first MR circuit 11 and the fifth MR circuit 15 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 fifth MR circuit 15 The bridge output V ₅ 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. 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 other MR element 162 is inclined 45 degrees clockwise and the other MR element 162 is inclined 45 degrees counterclockwise. 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 slope characteristics of the bridge outputs of the second MR circuit 12 and the sixth MR circuit 16 are opposite to each other. That is, the second MR circuit 12, while the direction of the magnetic field incident is increased bridge output V ₂ as in the counterclockwise direction (shift position D side) with respect to the horizontal, of the 6 MR circuit 16 The bridge output V ₆ increases as the direction of the incident magnetic field is clockwise (shift position F side) with respect to the horizontal.

FIG. 13A is a schematic diagram showing a pattern of the seventh MR circuit 17 according to the embodiment of the present invention, and FIG. 13B is a schematic diagram showing the circuit with symbols. As shown in FIGS. 13A and 13B, the seventh MR circuit 17 includes two MR elements 171 and 172 whose current directions are orthogonal to each other and connected in series. The MR element 172 is inclined 45 degrees counterclockwise and the other MR element 172 is inclined 45 degrees clockwise. The seventh MR circuit 17 is configured by a half-bridge circuit in which a constant voltage Vs is supplied to the terminal 173 of the MR element 171 and GND is connected to the terminal 174 of the MR element 172. The divided bridge output V ₇ is output from the terminal 175.

Here, the third MR circuit 13 and the seventh MR circuit 17 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 A side) with respect to the horizontal, MR circuit 17 of the seventh , the direction of the magnetic field incident bridge output V ₇ more in the counterclockwise direction (shift position C side) is increased with respect to the horizontal.

FIG. 14A is a schematic diagram showing a pattern of the eighth MR circuit 18 according to the embodiment of the present invention, and FIG. 14B is a schematic diagram showing the circuit by symbols. As shown in FIGS. 14A and 14B, the eighth MR circuit 18 includes two MR elements 181 and 182 whose current directions are orthogonal to each other and connected in series. The MR element 182 is inclined 45 degrees counterclockwise and the other MR element 182 is inclined 45 degrees clockwise. The eighth MR circuit 18 is configured by a half bridge circuit in which a constant voltage Vs is supplied to the terminal 183 of the MR element 181 and GND is connected to the terminal 184 of the MR element 182. Then, the divided bridge output V ₈ is outputted from the terminal 185.

Here, the fourth MR circuit 14 and the eighth MR circuit 18 have the slope characteristics of the bridge outputs opposite to each other. That is, the fourth MR circuit 14, while the direction of the magnetic field incident bridge output V ₄ higher in the clockwise direction (shift position D side) is increased with respect to the horizontal, MR circuit 18 of the eighth , the direction of the magnetic field incident bridge output V ₈ as in the counterclockwise direction (shift position F side) increases with respect to the horizontal.

As shown in FIG. 5, the position detection device 1 further includes a first differential amplifier 31 that computes and amplifies the voltage difference between the bridge outputs V ₁ and V ₅ of the first and fifth MR circuits 11 and 15; The second differential amplifier 32 for calculating and amplifying the voltage difference between the bridge outputs V ₃ and V ₇ of the third and seventh MR circuits 13 and 17, and the bridge output V of the second and sixth MR circuits 12 and 16. _2, a third differential amplifier 33 to the operational amplifier a voltage difference of _{V 6,} a fourth difference that the operational amplifier a voltage difference of the fourth and bridge output _V 4 of the eighth MR circuits 14, 18, _{V 8} A dynamic amplifier 34; a fifth differential amplifier 35 for calculating and amplifying a voltage difference between the bridge outputs V ₂ and V ₃ of the second and third MR circuits 12 and 13; a sixth and a seventh MR circuit 16; a voltage difference of the bridge output _V 6, _{V 7} of 17 the sixth differential amplifier 36 to operational amplifier It is provided.

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 is interlocked along the _first to third movement lines y ₁ , y ₂ , and 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, with respect to the third MR circuit 13, for example, at the position of the magnet 20 of the same first on moving line y ₁ and the bridge output V ₃ based on the magnetic field of the incident angle theta ₁₃ from the magnet 20, the formula It is represented by (4).

V ₃ = [{R ₀ −ΔR cos ² (θ ₁₃ + 45 °)} / {2R ₀ −ΔR}] × Vs Formula (4)

Regarding the fifth MR circuit 15, for example, the bridge output V ₅ 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 expressed by the following equation. It is represented by (5).
V ₅ = [{R ₀ −ΔR cos ² (θ ₁₅ −45 °)} / {2R ₀ −ΔR}] × Vs Formula (5)

Further, with respect to the seventh MR circuit 17, for example, at the position of the magnet 20 of the same first on moving line y ₁ and the bridge output V ₇ based on the magnetic field of the incident angle theta ₁₇ Kara from the magnet 20 , Expressed by Equation (6).
V ₇ = [{R ₀ −ΔR cos ² (θ ₁₇ −45 °)} / {2R ₀ −ΔR}] × Vs Formula (6)

FIG. 15 shows the positions of the magnets on the _first movement line y ₁ and the differential outputs V ₃₁ (= V ₁ −V ₅ ) and V ₃₂ (= V ₃ −V) based on the equations (3) to (6). ₇ ) is a graph showing the relationship with ( ₇ ). In FIG. 15, 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. 15, for example, the distance d ₂ is twice the distance d ₁ (2 × d ₁ = d ₂ ), the maximum resistance change rate is 2% (ΔR / R ₀ = 0.02), This is obtained by calculating the constant voltage Vs as 5 V and the amplification factors 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 incident angles θ ₁₁ , θ ₁₃ , θ ₁₅ , and θ ₁₇ described above are expressed by, for example, equations (7) to (10). It is represented by
^{_{θ 11 = tan -1 {(y}} -d 2/2) / d 1} Equation (7)
^{_{θ 13 = tan -1 {(y}} -d 2/2) / d 1} Equation (8)
^{_{θ 15 = tan -1 {(y}} + d 2/2) / d 1} Equation (9)
^{_{θ 17 = tan -1 {(y}} + d 2/2) / d 1} Equation (10)

As illustrated in FIG. 15, 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 ₁₅ of the magnetic fields incident on the first MR circuit 11 and the fifth MR circuit 15 is approximately as shown by the 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. 15 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 _{2 of} the second, fourth, sixth and eighth MR circuits 12, 14, 16, 18, V ₄ , V ₆ , and V ₈ are expressed by, for example, equations (11) to (14), respectively.
V ₂ = [{R ₀ −ΔR cos ² (θ ₂₂ + 45 °)} / {2R ₀ −ΔR}] × Vs Formula (11)
V ₄ = [{R ₀ −ΔR cos ² (θ ₂₄ + 45 °)} / {2R ₀ −ΔR}] × Vs Formula (12)
V ₆ = [{R ₀ −ΔR cos ² (θ ₂₆ −45 °)} / {2R ₀ −ΔR}] × Vs Formula (13)
V ₈ = [{R ₀ −ΔR cos ² (θ ₂₈ −45 °)} / {2R ₀ −ΔR}] × Vs Formula (14)

FIG. 16 shows the positions of the magnets on the _second movement line y ₂ and the differential outputs V ₃₃ (= V ₂ −V ₆ ) and V ₃₄ (= V ₄ −V) based on the equations (11) to (14). It is a graph which shows the relationship with ₈ ). 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. In the graph shown in FIG. 16, for example, as in FIG. 15, the distance d ₂ is twice the distance d ₁ (2 × 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 5 V, and the amplification factors of the differential amplifiers 33 and 34 are 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 fourth MR circuit 14 is input. The incident angle of the incident magnetic field is θ ₂₄ , the incident angle of the magnetic field incident on the sixth MR circuit 16 is θ ₂₆ , and the incident angle of the magnetic field incident on the eighth MR circuit 18 is θ ₂₈ .

As shown in FIG. 16, 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 ₂ , V _{3 of} the second, third, sixth and seventh MR circuits 12, 13, 16, 17 are provided. , V ₆ , V ₇ are represented by, for example, equations (15) to (18), respectively.
V ₂ = [{R ₀ −ΔR cos ² (θ ₃₂ −45 °)} / {2R ₀ −ΔR}] × Vs Formula (15)
V ₃ = [{R ₀ −ΔR cos ² (θ ₃₃ + 45 °)} / {2R ₀ −ΔR}] × Vs Formula (16)
V ₆ = [{R ₀ −ΔR cos ² (θ ₃₆ −45 °)} / {2R ₀ −ΔR}] × Vs Formula (17)
V ₇ = [{R ₀ −ΔR cos ² (θ ₃₇ + 45 °)} / {2R ₀ −ΔR}] × Vs Formula (18)

FIG. 17 shows the positions of the magnets on the third movement line x and the differential outputs V ₃₅ (= V ₃ −V ₂ ) and V ₃₆ (= V ₇ −V ₆ ) based on the equations (15) to (18). ). In FIG. 17, 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. 17, for example, as in FIG. 15, the distance d ₂ is twice the distance d ₁ (2 × 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 5 V, 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 the incident light is incident on the third MR circuit 13. The incident angle of the magnetic field to be incident is θ ₃₃ , the incident angle of the magnetic field incident to the sixth MR circuit 16 is θ ₃₆ , and the incident angle of the magnetic field incident to the seventh MR circuit 17 is θ ₃₇ .

As illustrated in FIG. 17, 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.

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 differential amplifier 31. , 32, the position detection of the shift positions A, B and C based on the outputs V ₃₁ and V ₃₂ is made effective. Further, 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 determination unit 40 performs differential operation. The position detection of the shift positions D, E and F based on the outputs V ₃₃ and V ₃₄ of the 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 fifth MR circuits 11 and 15 serving as the basis of the output V ₃₁ and the detection system of the third and seventh MR circuits 13 and 17 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.

  In addition, 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 17 ... 7th MR circuit 18 ... 1st 8 MR circuits, 20: magnets, 31, 32, 33, 34, 35, 36 ... differential amplifiers, 40 ... position determination units, 100 ... MR elements, 101 ... magnetic sensing units, 102, 103 ... terminals, 111, DESCRIPTION OF SYMBOLS 112 ... MR element, 113, 114 ... Terminal, 121, 122 ... MR element, 123, 124 ... Terminal, 131, 132 ... MR element, 133, 134 ... Terminal, 141, 142 ... MR element, 143, 144 ... Terminal 151 152 ... MR elements, 53, 154 ... terminal, 161,162 ... MR element, 163,164 ... terminal, 171,172 ... MR element, 173,174 ... terminal, 181,182 ... MR element, 183,184 ... terminal, A, B, C , D, E, F ... shift position, H ... magnetic field vector, I ... current direction, MF ... magnetic flux, R ₀ ... initial resistance value, ΔR ... 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 ₂ , V ₃ , V ₄ , V ₅ , V ₆ , V ₇ , V ₈ ... 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, 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 at a position on the same side as the first MR sensor with respect to the second straight line;
A third MR sensor provided at a position opposite to the first MR sensor with respect to the first straight line;
A fourth MR sensor provided at a position opposite to the second MR sensor with respect to the second straight line;
A fifth 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 detector that detects the position of the magnetic field generator in the first and second straight lines based on the outputs of the first to third MR sensors and the fifth MR sensor ;
The second MR sensor is disposed between the first and third MR sensors, and the third MR sensor is disposed between the second and fourth MR sensors. A sixth MR sensor provided apart from the second MR sensor in a direction parallel to the second straight line and having an output tilt characteristic opposite to that of the second MR sensor;
A seventh MR sensor provided apart from the third MR sensor in a direction parallel to the first straight line and having an output tilt characteristic opposite to that of the third MR sensor;
An eighth MR sensor provided apart from the fourth MR sensor in a direction parallel to the second straight line and having an output inclination characteristic opposite to that of the fourth MR sensor;
The position detection apparatus according to claim 1 . The position detector is configured to output the magnetic field generator in the first straight line based on at least one output of the outputs of the first and fifth MR sensors or the outputs of the third and seventh MR sensors. The position detection device according to claim 2 which detects a position. The position detection unit is configured to output the magnetic field generation unit in the second straight line based on at least one output of the outputs of the second and sixth MR sensors or the outputs of the fourth and eighth 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 detects a position of the magnetic field generation unit in the third straight line based on outputs of the second and third MR sensors or outputs of the sixth and seventh MR sensors. Item 5. The position detection device according to Item 4 .

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