WO2019167449A1 - Linear position sensor - Google Patents

Abstract

A linear position sensor detects the position of a target (400) the direction of movement thereof, the target (400 being constituted from a magnetic body, and projections (401) and recesses (402) being alternately provided therein. The linear position sensor includes a detection part (123) and a signal processing part (124). When the detection part is to detect the position of the target in the movement direction in a range from the center position (405) of a projection to the center position (406) of an adjacent projection, the target is provided with at least three recesses. When the detection part is to detect the position of the target in the movement direction in a range from the center position (403) of a recess to the center position (404) of an adjacent recess, the target is provided with at least two recesses. When the detection part is to detect the position of the target in the movement direction in a range from the edge position (407) of a projection and a recess to the edge position (408) of an adjacent projection and an adjacent recess, the target is provided with at least two recesses.

Description

Linear position sensor Cross-reference of related applications

This application is based on Japanese Patent Application No. 2018-35819 filed on February 28, 2018, the contents of which are incorporated herein by reference.

This disclosure relates to a linear position sensor.

Conventionally, an apparatus for detecting the position of a target using an optical detection element has been proposed in Patent Document 1, for example. The detection element includes a light source, a fixed slit, and a light receiving unit that receives light transmitted through the fixed slit. The target is provided with a pattern in which light reflecting portions and non-reflecting portions are alternately continued. For this reason, a part of the light emitted from the light source is reflected by the reflection portion to be detected and reaches the fixed slit.

In the fixed slit, reflective portions and non-reflective portions are alternately and continuously provided at the same pitch distance as the slit pattern of the target. Therefore, when the target moves relative to the fixed slit, the amount of light detected in the light receiving portion changes periodically and light and dark are repeated. By counting the number of light and dark repetitions, the amount of movement of the target can be measured.

Japanese Unexamined Patent Publication No. 2016-205854

Here, a method of detecting the position of the target by a magnetic detection element is known. In this method, for example, the position of the target is detected based on a change in the magnetic field that the detection unit receives from the concavo-convex shape with respect to the target moving in the arrangement direction of the concavo-convex shape. The inventors have invented a linear position sensor including a detection unit and a signal processing unit using this method.

Specifically, the detection unit corresponds to a plurality of ranges arranged in one direction along the moving direction of the target based on the change of the magnetic field received from the target as the target made of a magnetic material moves. At the same time, a plurality of detection signals having different phases are generated. The plurality of ranges is, for example, a concave or convex range having an uneven shape.

In addition, the signal processing unit acquires a plurality of detection signals from the detection unit, and compares the plurality of detection signals with a threshold value. Then, the signal processing unit specifies the position of the detection target as the position of any one of the plurality of ranges based on the combination of magnitude relationships between the plurality of detection signals and the threshold values.

∙ With the above configuration, the position of any one of a plurality of ranges can be specified. It is also possible to generate an output signal whose signal value increases at a constant increase rate with respect to the amount of movement of the target based on a plurality of detection signals.

However, in the end range of the plurality of ranges, the influence of the magnetic field received from the range not corresponding to the end by the detection unit is different from the effect of the magnetic field received from the end range. This is because there is another range next to one of the end ranges, but there is no other range next to the other. For this reason, the linearity of the signal value corresponding to the end range of the output signal is lost. Therefore, it is difficult to accurately detect the position corresponding to the end range.

This disclosure is intended to provide a linear position sensor that can improve the linearity of a signal value that increases at a constant rate of increase with respect to the amount of movement of a target.

According to the first aspect of the present disclosure, the linear position sensor detects the position of the target in the moving direction, which is made of a magnetic material and is provided with convex portions and concave portions alternately.

The linear position sensor includes a detection unit and a signal processing unit. The detection unit includes a magnet and a plurality of magnetic detection elements. The magnet generates a bias magnetic field. The plurality of magnetic detection elements generate a detection signal having a phase corresponding to the position of the convex portion and the concave portion based on a change in the magnetic field received from the target as the target moves, while a bias magnetic field is applied. The detection unit acquires a sine signal indicating a sine function and a cosine signal indicating a cosine function based on a plurality of detection signals having different phases.

The signal processing unit acquires a sine signal and a cosine signal from the detection unit, generates an arc tangent function based on the amount of movement of the target and indicates an arc tangent function based on the sine signal and the cosine signal, and outputs the arc tangent signal to the target. Is acquired as a position signal indicating the position of.

According to the second aspect of the present disclosure, the linear position sensor detects the position of the target in the moving direction. The target is made of a magnetic material, and the convex and concave portions are arranged obliquely with respect to the moving direction because the arrangement direction in which the convex and concave portions are alternately arranged is inclined with respect to the moving direction. Have a different shape.

The linear position sensor includes a detection unit and a signal processing unit. The detection unit includes a first magnetic detection element and a second magnetic detection element. The first magnetic detection element acquires a sine signal indicating a sine function as a signal having different phases corresponding to the positions of the convex portion and the concave portion based on a change in the magnetic field received from the target as the target moves. The second magnetic detection element acquires a cosine signal indicating a cosine function.

The signal processing unit acquires a sine signal and a cosine signal from the detection unit, generates an arc tangent function based on the amount of movement of the target and indicates an arc tangent function based on the sine signal and the cosine signal, and outputs the arc tangent signal to the target. Is acquired as a position signal indicating the position of.

In the first aspect and the second aspect, when the detection unit detects the position of the range from the center position of the convex part to the center position of the adjacent convex part in the moving direction of the target, the target is provided with at least three concave parts. ing.

When the detection unit detects a position in the range from the center position of the recess in the moving direction of the target to the center position of the adjacent recess, the target is provided with at least two recesses.

When the detection unit detects a position in a range from the edge position of the convex portion and the concave portion in the moving direction of the target to the edge position of the adjacent convex portion and the adjacent concave portion, the target has at least two concave portions. Yes.

According to this, the convex part or the concave part is located outside the movement range detected by the detection part among the targets. Thereby, the influence of the magnetic field that the detection unit receives from outside the target movement range can be brought close to the influence of the magnetic field that is received from within the target movement range. Accordingly, the waveforms of the sine signal and the cosine signal acquired by the signal processing unit can be brought close to ideal waveforms. Therefore, the linearity of the signal value of the arc tangent signal that increases at a constant increase rate with respect to the amount of movement of the target can be improved.

The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. In the accompanying drawings,
FIG. 1 is an external view of a linear position sensor according to the first embodiment. FIG. 2 is an exploded perspective view of components constituting a magnetic detection method using a magnetoresistive element, FIG. 3 is a plan view of each component shown in FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. FIG. 5 is a plan view showing components constituting a magnetic detection method using a Hall element, 6 is a cross-sectional view taken along the line VI-VI in FIG. FIG. 7 is a diagram showing a circuit configuration of the linear position sensor. FIG. 8 is a diagram showing the contents of signal processing of the circuit configuration shown in FIG. FIG. 9 is a diagram showing a sine signal, a cosine signal, and an arctangent signal corresponding to the convex and concave portions of the target, FIG. 10 is a diagram showing a sine signal and a cosine signal when a magnetoresistive element is mounted on a sensor chip. FIG. 11 is a diagram showing a sine signal and a cosine signal when a Hall element is mounted on the sensor chip. FIG. 12 is a diagram illustrating the first position signal and the second position signal with respect to the amount of movement of the target. FIG. 13 is a diagram showing a case where the center position of the convex portion and the position of the vertex of the sine signal match, FIG. 14 is a diagram showing a case where the positions of the edges of the convex part and the concave part coincide with the position of the vertex of the sine signal, FIG. 15 is a diagram showing a case where the positions of the edges of the convex part and the concave part coincide with the position of the vertex of the cosine signal, FIG. 16 is a diagram showing a configuration in which the gap of the magnetoresistive element with respect to the target is varied. FIG. 17A is a diagram showing the distance y, FIG. 17B is a diagram showing the relationship between the distance y and the magnetic amplitude for each signal shown in FIG. FIG. 18 is a diagram showing a case where five magnetoresistive elements are mounted on a sensor chip. FIG. 19 is a diagram showing a case where the width of the convex portion outside the moving range of the target is wider than the width of the convex portion within the moving range, FIG. 20 is a diagram showing a case where a wall is provided outside the movement range of the target, FIG. 21 is a diagram illustrating a case where the width of the convex portion outside the moving range of the target is narrower than the width of the convex portion within the moving range; FIG. 22 is a perspective view of a target according to the second embodiment, FIG. 23 is a diagram illustrating a sine signal, a cosine signal, and an arc tangent signal in the target illustrated in FIG. FIG. 24 is a perspective view showing a target for detecting the position of a movement range from a recess to an adjacent recess, FIG. 25 is a view showing a modified example according to the second embodiment, FIG. 26 is a diagram showing a modification according to the second embodiment. FIG. 27 is a diagram showing a modification according to the second embodiment. FIG. 28 is a view showing a modified example according to the second embodiment, FIG. 29 is a diagram showing a modification according to the second embodiment, FIG. 30A is a diagram showing an end face of a rotating plate in a modification according to the second embodiment; FIG. 30B is a view showing the outer peripheral surface of the rotating plate shown in FIG. 30A; FIG. 31 is a diagram illustrating a target and a detection unit according to the third embodiment. 32 is a sectional view taken along line XXXII-XXXII in FIG. FIG. 33 is a diagram showing a modification according to the third embodiment. FIG. 34 is a schematic view of a shift-by-wire system according to the fourth embodiment. FIG. 35 is a block diagram of a shift-by-wire system, FIG. 36 is a plan view showing a detent, FIG. 37 is a diagram showing the contents for detecting the position of the detent. FIG. 38 is a perspective view of a manual valve, FIG. 39 is a diagram showing the contents for detecting the position of the manual valve.

Hereinafter, a plurality of modes for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, portions corresponding to those described in the preceding embodiment may be denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each embodiment, the other embodiments described above can be applied to other parts of the configuration. Not only combinations of parts that clearly show that combinations are possible in each embodiment, but also combinations of the embodiments even if they are not explicitly stated unless there is a problem with the combination. Is also possible.

(First embodiment)
Hereinafter, a first embodiment of the present disclosure will be described with reference to the drawings. The linear position sensor according to the present embodiment is a sensor that detects the position of the detection target in the moving direction, which is made of a magnetic material and is provided with convex portions and concave portions alternately. Hereinafter, the linear position sensor is simply referred to as a sensor.

The sensor 100 shown in FIG. 1 detects the amount of movement of a target that moves in one direction as a detection target. That is, the sensor 100 detects the current position of the target. Specifically, the sensor 100 acquires the position of the target by detecting a signal proportional to the amount of movement of the target.

The sensor 100 includes a case 101 formed by resin molding of a resin material such as PPS. The case 101 has a tip 102 on the target side, a flange 103 fixed to the peripheral mechanism, and a connector 104 to which a harness is connected. A sensing portion is provided inside the tip portion 102.

Also, the sensor 100 is fixed to the peripheral mechanism via the flange portion 103 so that the tip portion 102 has a predetermined gap with respect to the detection surface of the target. Accordingly, the target moves relative to the sensor 100. Note that the moving direction of the target is not limited to rectilinear movement or reciprocation, but may be rotation or reciprocation within a specific angle.

The sensor 100 can employ a magnetic detection method using a magnetoresistive element or a magnetic detection method using a Hall element. In the case of a magnetic detection method using a magnetoresistive element, as shown in FIG. 2, the sensor 100 includes a mold IC part 105, a magnet 106, and a cap part 107. These are housed in the tip portion 102 of the case 101. The mold IC part 105 is inserted into the hollow cylindrical magnet 106. The magnet 106 generates a bias magnetic field and is inserted into the bottomed cylindrical cap portion 107.

As shown in the schematic plan view of FIG. 3 and the schematic sectional view of FIG. 4, the mold IC part 105, the magnet 106, and the cap part 107 are integrated. The main part of the mold IC part 105 is located in the hollow part of the magnet 106. The cap part 107 fixes the positions of the mold IC part 105 and the magnet 106.

The mold IC part 105 includes a lead frame 108, a processing circuit chip 109, a sensor chip 110, and a mold resin part 111. The lead frame 108 has a plate-like island portion 112 and a plurality of leads 113 to 116. The plane part of the island part 112 is arranged in parallel to the gap direction with respect to the target.

The plurality of leads 113 to 116 correspond to a power supply terminal 113 to which a power supply voltage is applied, a ground terminal 114 to which a ground voltage is applied, a first output terminal 115 for outputting a signal, and a second output terminal 116. . That is, the leads 113 to 116 are four for power supply, ground, and signal. Terminals 117 are connected to the tips of the leads 113 to 116, respectively. The terminal 117 is located in the connector part 104 of the case 101. A terminal 117 is connected to the harness.

In this embodiment, the ground lead 114 of the plurality of leads 113 to 116 is integrated with the island portion 112. The island portion 112 and all the leads 113 to 116 may be completely separated.

The processing circuit chip 109 and the sensor chip 110 are mounted on the island portion 112 with an adhesive or the like. The processing circuit chip 109 constitutes a circuit unit that processes signals from the sensor chip 110. The sensor chip 110 includes a magnetoresistive element whose resistance value changes when affected by a magnetic field from the outside. The magnetoresistive element is, for example, AMR (Anisotropic Magneto Resistance; AMR), GMR (Giant Magneto Resistance; GMR), or TMR (Tunneling Magneto Resistance; TMR). Each lead 113 to 116 and the processing circuit chip 109 are electrically connected via a wire 118. The processing circuit chip 109 and the sensor chip 110 are electrically connected via a wire 119.

The mold resin portion 111 seals the island portion 112, a part of each of the leads 113 to 116, the processing circuit chip 109, and the sensor chip 110. The mold resin portion 111 is molded into a shape that is fixed to the hollow portion of the magnet 106.

The detection signal by the magnetic detection method using the magnetoresistive element will be described. The cap unit 107 is disposed with a predetermined gap with respect to the target. When the gap increases, the amplitude of the detection signal decreases, and when the gap decreases, the amplitude of the detection signal increases. The position of the target can be detected using the detection signal. As will be described later, the detection signal is generated by outputs of a plurality of magnetoresistive elements.

The magnetoresistive element that detects the magnetic vector has the merit of canceling the accuracy error due to the gap shift. Further, there is a merit that the influence of the stress generated in the sensor chip 110 can be reduced or canceled. Therefore, highly accurate detection is possible.

When the magnetic detection method using the Hall element is adopted, the mold IC portion 105 is inserted into the cap portion 107 and fixed as shown in the schematic plan view of FIG. 5 and the schematic sectional view of FIG. The mold IC unit 105 includes a lead frame 108, an IC chip 120, a magnet 121, and a mold resin unit 111.

The island part 112 of the lead frame 108 is arranged so that the plane part is parallel to the moving direction of the target. On the other hand, the leads 113 to 116 are arranged so as to be perpendicular to the moving direction of the target. A ground lead 114 is integrated with the island portion 112 at a right angle. Terminals 117 are connected to the tips of the leads 113 to 116, respectively.

The IC chip 120 is formed with a plurality of Hall elements and a signal processing circuit unit. That is, the magnetic detection system using the Hall element has a one-chip configuration. The magnet 121 is fixed to the surface of the island part 112 opposite to the IC chip 120. Each lead 113 to 116 and the IC chip 120 are electrically connected via a wire 122. The mold resin portion 111 is molded into a shape that is fixed to the hollow portion of the cap portion 107.

A detection signal by a magnetic detection method using a Hall element will be described. For example, when two Hall elements are provided in the IC chip 120, when the target moves with respect to the cap portion 107, each detection signal becomes maximum corresponding to the position of each Hall element. The relationship between the gap and the amplitude of the detection signal is the same as in the magnetic detection method using the magnetoresistive element. The position of the target can be detected by using a periodic signal corresponding to the movement of the target.

Next, the circuit configuration configured in the sensor chip 110 and the processing circuit chip 109 will be described. As shown in FIG. 7, the sensor 100 and the ECU 200 are electrically connected via a harness 300. As described above, since the mold IC unit 105 has the four leads 113 to 116, the harness 300 is constituted by four wires.

The ECU 200 is an electronic control device that includes a power supply unit 201, a control unit 202, and a ground unit 203. The power supply unit 201 is a circuit unit that supplies a power supply voltage to the sensor 100. The control unit 202 is a circuit unit that performs predetermined control according to the position signal input from the sensor 100. Note that the control unit 202 may be configured as a circuit unit corresponding to each of the output terminals 115 and 116. The ground unit 203 is a circuit unit that sets the ground voltage of the sensor 100.

The sensor 100 includes a detection unit 123 and a signal processing unit 124. The detection unit 123 includes a sensor chip 110. The signal processing unit 124 is provided in the processing circuit chip 109. The detection unit 123 and the signal processing unit 124 operate based on the power supply voltage and the ground voltage supplied from the ECU 200.

The detection unit 123 includes a first detection unit 125 and a second detection unit 126. The first detection unit 125 is configured to output a first detection signal corresponding to the position of the target. The second detection unit 126 is configured to output a second detection signal corresponding to the position of the target. The detection units 125 and 126 have the same configuration and output the same detection signal.

As shown in FIG. 8, each of the detection units 125 and 126 includes a first magnetoresistive element 127, a second magnetoresistive element 128, and a third magnetoresistive element 129 whose resistance values change as the target moves. It has two elements. In FIG. 8, one detection unit is illustrated.

Each is arranged such that the second magnetoresistive element 128 is positioned between the first magnetoresistive element 127 and the third magnetoresistive element 129 in the moving direction of the target. That is, the second magnetoresistive element 128 is disposed so as to be sandwiched between the first magnetoresistive element 127 and the third magnetoresistive element 129. A bias magnetic field along the central axis of the magnet 106 is applied to the second magnetoresistive element 128. On the other hand, a bias magnetic field that entrains the end of the magnet 106 is applied to the first magnetoresistive element 127 and the third magnetoresistive element 129.

Each of the magnetoresistive elements 127 to 129 is configured as a half bridge circuit in which two magnetoresistors are connected in series between a power source and a ground. Each of the magnetoresistive elements 127 to 129 detects a change in resistance value when the two magnetoresistances are affected by the magnetic field as the target moves. Each of the magnetoresistive elements 127 to 129 outputs the voltage at the midpoint between the two magnetoresistors as a waveform signal based on the change in the resistance value.

Further, each of the detection units 125 and 126 includes first to fourth operational amplifiers in addition to the magnetoresistive elements 127 to 129. When the midpoint potential of the midpoint of the first magnetoresistive element 127 is defined as V1, and the midpoint potential of the midpoint of the second magnetoresistive element 128 is defined as V2, the first operational amplifier calculates V1−V2. The differential amplifier is configured to output the calculation result as R1. When the midpoint potential of the midpoint of the third magnetoresistive element 129 is defined as V3, the second operational amplifier is a differential amplifier configured to calculate V2-V3 and output the calculation result as R2. .

The third operational amplifier receives R1 (= V1−V2) from the first operational amplifier and R2 (= V2−V3) from the second operational amplifier, calculates R2−R1, and outputs the calculation result as S1 (= (V2 A differential amplifier configured to output as -V3)-(V1-V2)).

The fourth operational amplifier inputs the midpoint potential V1 from the midpoint of the first magnetoresistive element 127 and also inputs the midpoint potential V3 from the midpoint of the third magnetoresistive element 129, and calculates V1-V3. A differential amplifier configured to output the result as S2.

As described above, the detection units 125 and 126 generate and output the signal S1 (= (V2-V3)-(V1-V2)) and the signal S2 (= V1-V3) from the outputs of the magnetoresistive elements 127 to 129, respectively. Is configured to get. The signal S1 and the signal S2 are detection signals. That is, each of the detection units 125 and 126 generates a plurality of detection signals having different phases. Each of the detection units 125 and 126 outputs the signal S1 and the signal S2 to the signal processing unit 124 as a plurality of detection signals.

Note that the signal processing described above is a case where three magnetoresistive elements are provided in the sensor chip 110. When two or four magnetoresistive elements are provided on the sensor chip 110, processing according to the number of element pairs is performed.

7 is a circuit unit that processes a signal input from the detection unit 123. The signal processing unit 124 in FIG. The signal processing unit 124 includes a first processing unit 130, a second processing unit 131, and a redundancy determining unit 132.

The first processing unit 130 receives the first detection signal from the first detection unit 125 and acquires the position of the target based on the first detection signal. The second processing unit 131 receives the second detection signal from the second detection unit 126 and acquires the position of the target based on the second detection signal.

The second processing unit 131 inverts and outputs the position signal. Therefore, if there is no abnormality in the detection unit 123 and the signal processing unit 124, the position signal of the first processing unit 130 and the position signal of the second processing unit 131 are added to a constant value.

Here, the first detection unit 125 and the first processing unit 130 constitute a first system. Moreover, the 2nd detection part 126 and the 2nd process part 131 comprise a 2nd system | strain. That is, a duplex system is configured by the detection units 125 and 126 and the processing units 130 and 131.

The redundancy determining unit 132 is a circuit unit that determines whether the position acquired by the first processing unit 130 matches the position acquired by the second processing unit 131. If the signal processing results of the two systems match, the signal processing unit 124 outputs each position signal as it is. If the signal processing results of the two systems do not match, there is a possibility that an abnormality has occurred in one or both of each system. In this case, the signal processing unit 124 outputs an abnormal signal indicating abnormality to the ECU 200.

The signal processing is summarized as shown in FIG. 8, for example. The analog process is a process for generating a plurality of detection signals. Note that the detection unit 123 may have a function of detecting temperature. The temperature information Temp is used for temperature correction. “Sin” and “Cos” are a sine signal and a cosine signal to be described later.

The analog signal subjected to analog processing is converted into a digital signal by an A / D converter (ADC) via a multiplexer (MUX). The digital signal is processed to produce an arctangent signal. In analog processing and arithmetic processing, adjustment values stored in the memory are used as appropriate. The position signal acquired by the arithmetic processing is output to the ECU 200 according to an output format such as DAC, SENT, or PWM.

Note that the arithmetic processing is performed by the signal processing unit 124. Therefore, an A / D converter (ADC) and a memory are provided in the signal processing unit 124. The above is the configuration of the sensor 100 according to the present embodiment.

Next, the target and the movement range will be described. As shown in FIG. 9, the target 400 is provided with convex portions 401 and concave portions 402 alternately in the movement direction. The detection unit 123 is fixed to the target 400 with a gap. The target 400 moves in the movement direction with respect to the detection unit 123.

Also, the detection unit 123 detects the position of the movement range from the valley center to the adjacent valley center. The valley center is the width center in the moving direction of the target 400 in the recess 402. The movement range is an operation range of the target 400 in the movement direction.

As described above, when the detection unit 123 detects the position in the range from the center position 403 of the recess 402 to the center position 404 of the adjacent recess 402 in the moving direction of the target 400, the target 400 is provided with at least two recesses 402. It has been. The center position 403 of the recess 402 corresponds to P1. The center position 404 of the recess 402 corresponds to P2. In other words, three convex portions 401 are provided.

Then, when the target 400 moves in the moving direction, the detection unit 123 crosses from the center position 403 of the recess 402 to the center position 404 of the adjacent recess 402 via the protrusion 401. Accordingly, the detection unit 123 generates the signal S1 and the signal S2 having different phases based on the change of the magnetic field received from the convex portion 401 and the concave portion 402 as the target 400 moves.

FIG. 10 shows the signal S1 and the signal S2 when the method using the magnetoresistive element among the above magnetic detection methods is adopted. FIG. 11 shows the signal S1 and the signal S2 when the method using the Hall element is adopted among the above magnetic detection methods. In this case, three Hall elements 133, 134, and 135 are mounted on the IC chip 120.

The signal S1 is a sine signal indicating a sine function. The signal S2 is a cosine signal indicating a cosine function. That is, the signal S1 and the signal S2 have a phase difference of ¼ period. In both detection methods, the convex portion 401 and the concave portion 402 are located outside the center positions 403 and 404 of the concave portion 402. For this reason, the influence of the magnetic field that the sensor chip 110 receives from the vicinity of the central positions 403 and 404 of the concave portion 402 is close to the influence of the magnetic field that is received from the vicinity of the convex portion 401 between the central positions 403 and 404. Therefore, the signal S1 and the signal S2 are close to ideal sine waves and cosine waves.

9 to 11, the detection unit 123 generates a cosine signal so that the vertex 136 of the cosine function is positioned at the center position 405 of the convex portion 401 in the movement direction. The detection unit 123 acquires a sine signal and a cosine signal and outputs them to the signal processing unit 124 as a plurality of detection signals.

The signal processing unit 124 acquires a plurality of detection signals from the detection unit 123, and acquires a position signal indicating the position of the target 400 based on the plurality of detection signals. Specifically, as shown in the middle part of FIG. 9, the signal processing unit 124 acquires a sine signal and a cosine signal corresponding to the position of the target 400. The signal processing unit 124 calculates (signal value of cosine signal) / (signal value of sine signal). As a result, as shown in the lower part of FIG. 9, an arc tangent signal is obtained which shows an arc tangent function and whose signal value increases at a constant increase rate according to the amount of movement of the target 400. The signal processing unit 124 acquires an arctangent signal as a position signal.

As shown in FIG. 12, the signal processing unit 124 outputs to the ECU 200 a first position signal (O1) and a second position signal (O2) obtained by inverting the first position signal (O1).

As a comparative example, in the target 400 of FIGS. 9 to 11, a shape in which the convex portion 401 is not provided outside the center positions 403 and 404 is conceivable. In this shape, there is one convex portion 401, and the convex portion 401 and the concave portion 402 are not continuous. For this reason, the degree to which the change of the magnetic field is non-uniform is higher than when the convex portion 401 and the concave portion 402 are continuous. As a result, distortion components included in the waveforms of the sine signal and cosine signal near the center positions 403 and 404 increase. Therefore, the obtained arctangent signal also includes a distortion component, and the accuracy of the position of the target 400 is also reduced.

In contrast, in this embodiment, when detecting the position between the center positions 403 and 404 of the recess 402, the target 400 is provided with at least two recesses 402. Thereby, the convex part 401 is necessarily located outside the movement range detected by the detection part 123 in the target 400. For this reason, the influence of the magnetic field that the detection unit 123 receives from outside the movement range of the target 400 can be brought close to the influence of the magnetic field that is received from within the movement range of the target 400. Along with this, it is possible to acquire a sine signal and a cosine signal close to an ideal waveform. Therefore, the linearity of the signal value of the arctangent signal that increases at a constant increase rate with respect to the amount of movement of the target 400 can be improved.

As a first modification, as illustrated in FIG. 13, the detection unit 123 detects a position in a range from the center position 405 of the protrusion 401 to the center position 406 of the adjacent protrusion 401 in the moving direction of the target 400. You may do it. In this case, the target 400 is provided with at least three concave portions 402. As illustrated in FIG. 13, the detection unit 123 may generate a sine signal so that the vertex 137 of the sine function is positioned at the center positions 405 and 406 of the convex portion 401 in the movement direction.

As a second modification example, as illustrated in FIG. 14, the detection unit 123 detects whether the adjacent convex portion 401 and the adjacent concave portion 402 from the edge position 407 between the convex portion 401 and the concave portion 402 in the moving direction of the target 400. Positions in the range up to the edge position 408 may be detected. In this case, the target 400 is provided with at least two recesses 402. As illustrated in FIG. 14, the detection unit 123 may generate a sine signal so that the vertex 137 of the sine function is located at the edge positions 407 and 408 between the convex portion 401 and the concave portion 402 in the movement direction. .

As a third modified example, as shown in FIG. 15, the detection unit 123 generates a cosine signal so that the vertex 136 of the cosine function is located at the edge positions 407 and 408 of the convex portion 401 and the concave portion 402 in the moving direction. It may be generated.

As a fourth modification, as shown in FIG. 16, the three magnetoresistive elements 127 to 129 may have different gaps with respect to the target 400. In this case, the signal S1 is S1 = V1 + V3−2V2. The signal S2 is S2 = V1-V3.

As shown in FIGS. 17A and 17B, the arrangement of the elements causes the first signal S1 to be fixed in a state where y in the Y direction increases, that is, the position of the second magnetoresistive element 128 in the Y direction is fixed. The magnetic amplitude increases as the magnetoresistive element 127 and the third magnetoresistive element 129 move away from the end 138 of the magnet 106. The Y direction is the gap direction, and the X direction is the moving direction. On the other hand, the magnetic amplitude of the signal S2 increases as y decreases, that is, as the second magnetoresistive element 128 approaches the end 138 of the magnet 106. Thus, the signal amplitude of the signal S1 can be increased by moving the first magnetoresistive element 127 and the third magnetoresistive element 129 that generate the signal S1 away from the end 138 of the magnet 106. Further, by bringing the second magnetoresistive element 128 that generates the signal S2 closer to the end 138 of the magnet 106, the magnetic amplitude of the signal S2 can be expanded regardless of the magnetic amplitude of the signal S1. That is, the signal amplitude of the signal S2 can be adjusted independently of the magnetic amplitude of the signal S1.

As shown in FIG. 18, by adding the fourth magnetoresistive element 139 and the fifth magnetoresistive element 140 to the sensor chip 110, the magnetic amplitude can be further improved. As an example, in the case of five elements, the signal S1 is S1 = V1 + V3−2V2, and the signal S2 is S2 = V4−V5.

As a fifth modification, as shown in FIGS. 19 to 21, when detecting the movement range between the center positions 403 and 404 of the concave portion 402, the shape of the convex portion 401 outside the movement range of the target 400 is: It may be different from the shape of the convex portion 401 within the movement range. FIG. 19 shows a case where the width in the moving direction of the convex portion 401 outside the moving range of the target 400 is wider than the width of the convex portion 401 within the moving range. FIG. 20 shows a case where the outside of the movement range of the target 400 is not the convex portion 401 but the wall portion 409. In the example of FIG. 20, the detection unit 123 may detect a position in a range between the edge positions 407 and 408 between the convex portion 401 and the concave portion 402. FIG. 21 shows a case where the width of the convex portion 401 outside the moving range of the target 400 is narrower than the width of the convex portion 401 within the moving range. Similarly, the movement range of the target 400 between the protrusions 401 and between the edges does not have to be the same shape as the movement range.

(Second Embodiment)
In the present embodiment, parts different from the first embodiment will be described. As shown in FIG. 22, in the target 400, the arrangement direction in which the convex portions 401 and the concave portions 402 are alternately arranged is inclined with respect to the moving direction. Thereby, the target 400 has a shape in which the convex portion 401 and the concave portion 402 are arranged obliquely with respect to the moving direction. The convex portion 401 and the concave portion 402 are laid out linearly in a direction orthogonal to the arrangement direction.

Further, as shown in FIG. 23, the sensor chip 110 of the detection unit 123 has one surface 141 on which the magnetoresistive elements 127 to 129 are mounted. The one surface 141 of the sensor chip 110 corresponds to, for example, a planar portion of the island portion 112. One surface 141 of the sensor chip 110 is mounted on the detection unit 123 so as to be parallel to the arrangement direction. Specifically, if the direction in which the detection unit 123 is arranged with a gap with respect to the target 400 is defined as the gap direction, the one surface 141 of the sensor chip 110 is arranged in parallel to the arrangement direction and the gap direction. This makes it easier to detect the magnetic field that the sensor chip 110 receives from the convex portion 401 and the concave portion 402. Therefore, the accuracy of the waveform signal, the sine signal, the cosine signal, and the arctangent signal is improved, so that the accuracy of the position of the target 400 can be improved.

22 and 23 show a case where the detection unit 123 detects the position of the movement range from the convex part 401 to the adjacent convex part 401. As shown in FIG. The position of the movement range from 402 to the adjacent recess 402 may be detected.

As a modification, as shown in FIGS. 25 to 28, the one surface 141 of the sensor chip 110 is arranged in various directions with respect to the arrangement direction and the movement direction. In FIG. 25, when the detection unit 123 detects the position of the movement range from the convex part 401 to the adjacent convex part 401, the one surface 141 of the sensor chip 110 is arranged in parallel to the movement direction of the target 400. The extending direction of the convex portion 401 and the concave portion 402 with respect to the moving direction of the target 400 is set in a range of 0 <θ <180 °.

In FIG. 26, when the detection unit 123 detects the position of the movement range from the convex part 401 to the adjacent convex part 401, the one surface 141 of the sensor chip 110 is arranged in parallel to the arrangement direction of the convex part 401 and the concave part 402. . In FIG. 27, when the detection unit 123 detects the position of the movement range from the concave portion 402 to the adjacent concave portion 402, the one surface 141 of the sensor chip 110 is arranged in parallel with the moving direction of the target 400. In FIG. 28, when the detection unit 123 detects the position of the movement range from the concave portion 402 to the adjacent concave portion 402, the one surface 141 of the sensor chip 110 is arranged in parallel to the arrangement direction of the convex portion 401 and the concave portion 402.

As a second modified example, as shown in FIG. 29, the target 400 may have a configuration including a rotating shaft 410 and a rotating plate 411. The rotating plate 411 has a surface 413 that is fixed to the side surface 412 of the rotating shaft 410 and is orthogonal to the central axis of the rotating shaft 410. The rotating plate 411 is a fan-shaped plate member. The detection unit 123 is disposed to face the one surface 413 of the rotating plate 411.

In the above configuration, the moving direction is a rotating direction around the central axis of the rotating shaft 410. In addition, the arrangement direction of the convex portion 401 and the concave portion 402 is a direction orthogonal to the central axis of the rotating shaft 410 around a position 414 that is separated from the central axis of the rotating shaft 410 in the radial direction of the rotating shaft 410. That is, the arrangement direction is a radial direction centered on the position 414.

A plurality of groove portions 415 are laid out in an arc shape on one surface 413 of the rotating plate 411 with a position radially away from the central axis of the rotating shaft 410 as a center. The groove portion 415 corresponds to the concave portion 402, and the portion between the groove portion 415 and the groove portion 415 corresponds to the convex portion 401. FIG. 29 shows an example in which the position of the movement range from the convex portion 401 to the adjacent convex portion 401 is shown, but the position of the movement range from the groove portion 415 to the adjacent groove portion 415 may be detected. Absent.

As a third modification, as shown in FIGS. 30A and 30B, a groove 417 may be formed on the outer peripheral surface 416 of the rotating plate 411. The detection unit 123 is disposed to face the outer peripheral surface 416 of the rotating plate 411. In the above configuration, the groove portion 417 is laid out in a spiral shape around the central axis of the rotation shaft 410 on the outer peripheral surface 416 of the rotation plate 411. Therefore, the convex portion 401 and the concave portion 402 are also laid out in a spiral shape. The arrangement direction is a direction along the arrangement of the convex portions 401 and the concave portions 402.

In the above, the direction of the one surface 141 of the sensor chip 110 in the magnetic detection method using the magnetoresistive element is shown. On the other hand, in the case of the sensor chip 110 in the magnetic detection method using the Hall element, the one surface 141 is disposed to face the target 400. Specifically, one surface 141 of the sensor chip 110 is arranged in parallel to the arrangement direction and is arranged perpendicular to the gap direction.

(Third embodiment)
In the present embodiment, parts different from the first and second embodiments will be described. In the present embodiment, the detection unit 123 has a configuration in which a sine signal is acquired from one element and a cosine signal is acquired from the other element. In the above configuration, as shown in FIG. 31, a target 400 in which the arrangement direction of the convex portion 401 and the concave portion 402 is inclined with respect to the moving direction is employed. Note that the one surface 141 of the sensor chip 110 is arranged in parallel to the arrangement direction of the convex portions 401 and the concave portions 402.

32, the detection unit 123 includes a first magnetic detection element 142 and a second magnetic detection element 143. Each of the magnetic detection elements 142 and 143 is a magnetoresistive element. The magnetic detection elements 142 and 143 are arranged at a distance corresponding to a quarter period of the arrangement of the convex portions 401 and the concave portions 402. As a result, the first magnetic detection element 142 generates a sine signal indicating a sine function. Further, assuming that one period is from the edge position 407 to the adjacent edge position 408, the second magnetic detection element 143 generates a cosine signal indicating a cosine function having a phase difference of ¼ period. That is, the detection unit 123 does not generate a sine signal and a cosine signal from a plurality of detection signals, but acquires an output signal of the element as a sine signal and a cosine signal.

Therefore, the signal processing unit 124 acquires the sine signal and the cosine signal from the detection unit 123, generates an arctangent signal from these signals, and acquires the arctangent signal as a position signal indicating the position of the target 400.

As a modified example, as shown in FIG. 33, each magnetic detection element 142, 143 may be configured as a Hall element. Also in this case, the magnetic detection elements 142 and 143 are arranged apart by a distance corresponding to a quarter period of the arrangement of the convex portions 401 and the concave portions 402.

(Fourth embodiment)
In the present embodiment, parts different from the first to third embodiments will be described. The target 400 according to the present embodiment is a movable part that moves in conjunction with the operation of the shift position of the vehicle. Specifically, the target 400 is applied to the shift-by-wire system 500 of the vehicle shown in FIGS.

In the shift-by-wire system 500, the ShBWECU 501 acquires information on the shifter 502 of the vehicle and controls the actuator 503. A fan-shaped detent 504 is fixed to the actuator 503. A manual valve 505 and a parking rod 506 are fixed to the detent 504. Manual valve 505 is connected to transmission 507. The parking rod 506 is connected to the parking mechanism 508. The sensor 100 is used to detect the position of the detent 504 and the position of the manual valve 505, for example.

The shift-by-wire system 500 includes a motor / encoder 509, a TCU 510, a solenoid 511, a pump 512, and the like. The ShBWECU 501 acquires range information indicating the position from the sensor 100 and controls the motor encoder 509 and the TCU 510. A TCU 510 is a transmission controller and controls the solenoid 511.

When the sensor 100 detects the position of the detent 504, the detent 504 becomes the target 400 as shown in FIG. Therefore, the detent 504 is provided with a convex portion 401 and a concave portion 402. The target 400 may be fixed to the detent 504. As shown in FIG. 37, the sensor 100 is fixed to the housing 513 so as to face the detent 504. Thus, when the detent 504 is rotated by the actuator 503, the sensor 100 detects the rotational position of the detent 504.

When the sensor 100 detects the position of the manual valve 505, the target 400 is fixed to the manual valve 505 as shown in FIG. A target 400 provided with a convex portion 401 and a concave portion 402 is fixed to the manual valve 505. Further, as shown in FIG. 39, the sensor 100 is fixed to the housing 513 so as to face the target 400. Thereby, when the manual valve 505 moves through the detent 504, the sensor 100 detects the position of the manual valve 505. It can be said that FIG. 35 shows a configuration for detecting the position of the manual valve 505.

When the shift position is operated, the position of the shift position can be detected by detecting the positions of the detent 504 and the manual valve 505 by the sensor 100.

The present disclosure is not limited to the above-described embodiment, and various modifications can be made as follows without departing from the spirit of the present disclosure.

For example, the application of the sensor 100 is not limited to a vehicle, and can be widely used for industrial robots, manufacturing facilities, and the like as detecting the position of a movable part. Further, the sensor 100 may not have a redundant function. In this case, the number of leads 113 to 116 is three.

Although the present disclosure has been described based on the embodiments, it is understood that the present disclosure is not limited to the embodiments and structures. The present disclosure includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, as well as other combinations and forms including only one element, more or less, are within the scope and spirit of the present disclosure.

Claims (8)

A linear position sensor that detects a position in a moving direction of a target (400) that is made of a magnetic material and has convex portions (401) and concave portions (402) provided alternately.
A magnet (106) for generating a bias magnetic field and the bias magnetic field are applied, and the position of the convex portion and the concave portion corresponds to the change of the magnetic field received from the target as the target moves. A plurality of magnetic detection elements (127, 128, 129, 133, 134, 135, 139, 140) that generate phase detection signals, and a sine function that exhibits a sine function based on the plurality of detection signals having different phases A detection unit (123) for acquiring a cosine signal indicating a signal and a cosine function;
The sine signal and the cosine signal are acquired from the detection unit, an arc tangent function is generated based on the sine signal and the cosine signal, and an arc tangent signal corresponding to the amount of movement of the target is generated, and the arc tangent signal is generated. A signal processing unit (124) that acquires a position signal indicating the position of the target;
Including
When the detection unit detects a position in a range from the central position (405) of the convex portion in the moving direction of the target to the central position (406) of the adjacent convex portion, the target has at least the concave portion. There are three,
When the detection unit detects a position in a range from the center position (403) of the recess in the moving direction of the target to the center position (404) of the adjacent recess, the target has at least two recesses. Provided,
The detection unit detects a position in a range from an edge position (407) between the convex portion and the concave portion in the moving direction of the target to an edge position (408) between the adjacent convex portion and the adjacent concave portion. A linear position sensor in which the target is provided with at least two of the recesses. In the target, the convex portion and the concave portion are arranged obliquely with respect to the moving direction because the arrangement direction in which the convex portion and the concave portion are alternately arranged is inclined with respect to the moving direction. The linear position sensor according to claim 1, which has a curved shape. The detection unit has a sensor chip (110) having one surface (141),
The linear position sensor according to claim 1, wherein the one surface of the sensor chip is arranged in parallel to an arrangement direction in which the convex portions and the concave portions of the target are alternately arranged. The detection unit generates the sine signal so that the vertex (137) of the sine function is positioned at the center position (405, 406) of the convex portion in the movement direction, or the vertex ( The linear position sensor according to any one of claims 1 to 3, wherein the cosine signal is generated so that 136) is located at a center position (405, 406) of the convex portion in the movement direction. The detection unit generates the sine signal so that a vertex (137) of the sine function is located at an edge position (407, 408) between the convex portion and the concave portion in the moving direction, or the cosine The cosine signal is generated according to any one of claims 1 to 3, wherein the cosine signal is generated so that a vertex (136) of a function is located at an edge position (407, 408) between the convex portion and the concave portion in the movement direction. Linear position sensor. Since the arrangement direction in which the convex portions (401) and the concave portions (402) are alternately arranged is inclined with respect to the moving direction, the convex portions and the concave portions are moved in the moving direction. A linear position sensor for detecting a position in the moving direction of a target (400) having an obliquely arranged shape;
A magnet (106) for generating a bias magnetic field and the bias magnetic field are applied, and the position of the convex portion and the concave portion corresponds to the change of the magnetic field received from the target as the target moves. A detection unit (123) having a first magnetic detection element (142) that acquires a sine signal indicating a sine function as a signal having a different phase and a second magnetic detection element (143) that acquires a cosine signal indicating a cosine function. )When,
The sine signal and the cosine signal are acquired from the detection unit, an arc tangent function is generated based on the sine signal and the cosine signal, and an arc tangent signal corresponding to the amount of movement of the target is generated, and the arc tangent signal is generated. A signal processing unit (124) that acquires a position signal indicating the position of the target;
Including
When the detection unit detects a position in a range from the central position (405) of the convex portion in the moving direction of the target to the central position (406) of the adjacent convex portion, the target has at least the concave portion. There are three,
When the detection unit detects a position in a range from the center position (403) of the recess in the moving direction of the target to the center position (404) of the adjacent recess, the target has at least two recesses. Provided,
The detection unit detects a position in a range from an edge position (407) between the convex portion and the concave portion in the moving direction of the target to an edge position (408) between the adjacent convex portion and the adjacent concave portion. A linear position sensor in which the target is provided with at least two of the recesses. The detection unit has a sensor chip (110) having one surface (141),
The linear position sensor according to claim 6, wherein the one surface of the sensor chip is arranged in parallel to an arrangement direction in which the convex portions and the concave portions of the target are alternately arranged. The linear position sensor according to any one of claims 1 to 7, wherein the target is a movable part that moves in conjunction with an operation of a shift position of a vehicle.

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