POSITION SENSOR, POSITION DETECTION SYSTEM AND STEERING SYSTEM USING THE SAME

Abstract

A position sensor (1), comprising: a magnetic sensor (3); a plurality of magnets (2) which are moved in a first direction (X) relative to the magnetic sensor (3), wherein one or some of the magnets (2) are arranged in a first track (5A) and the remaining magnets (2) are arranged in a second track (5B), wherein the magnetic sensor (3) includes: a first magnetic field detection element (9A) arranged in the first track (5A), a first processor (4A) that outputs a voltage VM1 when a rotation angle of a first magnetic field applied to the first magnetic field detection element (9A) is less than a first threshold (S21), and that outputs a predetermined high voltage VH when the rotation angle of the first magnetic field is equal to or greater than the first threshold (S21), wherein the voltage VM1 is a voltage between a predetermined low voltage VL and the high voltage VH and indicates positions of the magnets (2) relative to the first magnetic field detection element (9A); a second magnetic field detection element (9B) arranged in the second track (5B); and a second processor (4B) that outputs the low voltage VL when a rotation angle of a second magnetic field applied to the second magnetic field detection element (9B) is less than a second threshold (S22), and that outputs a voltage VM2 when the rotation angle of the second magnetic field is equal to or greater than the second threshold (S22), wherein the voltage VM2 is a voltage between the low voltage VL and the high voltage VH and indicates positions of the magnets (2) relative to the second magnetic field detection element (9B).

Description

BACKGROUND OF THE INVENTION 1. Field of the invention:

[0001] The present application is based on JP2020-33436, filed on 28 February 2020 and published as JP 2021 - 135 241 A, and claims its priority.

[0002] The present invention relates to a position sensor which uses a magnetic sensor, as well as a position detection system which uses this, and a steering system which uses this. 2. Description of the state of the art

[0003] A position sensor that uses a magnetic sensor is known. A position sensor has a plurality of magnets arranged in series in a moving element, and a magnetic sensor is arranged in a stationary element. When the moving element is moved, the magnets move relative to the magnetic sensor. The magnetic sensor detects a change in a magnetic field caused by the relative movement and thereby detects the positions of the magnets, i.e., the position of the moving element. JP2011-137796 discloses a position sensor with four or five magnets arranged in series.

[0004] DE 10 2016 218 530 A1, DE 10 2014 200 945 A1 and DE 198 18 799 A1 each show a position sensor. DE 102 43 157 A1 shows an operational amplifier. JP H08 - 327 394 A shows a magnetic rotary encoder. JP 2007 - 51 901 A shows a magnetic sensor. SUMMARY OF THE INVENTION

[0005] In the position sensor disclosed in JP 2011-137796A, a plurality of magnets are arranged in series. Accordingly, if the range or stroke of the detection positions is long, the size of the magnets is increased to obtain the required intensity of a magnetic field, and the distance between the magnets and the magnetic sensor is also increased. As a result, the size of the position sensor is increased.

[0006] The present invention aims to provide a position sensor that can detect a position along a long stroke and that can limit an increase in size.

[0007] According to one aspect of the present invention, a position sensor comprises: a magnetic sensor; a plurality of magnets that are moved in a first direction relative to the magnetic sensor, wherein one or some of the magnets are arranged in a first track and the remaining magnets are arranged in a second track. The magnetic sensor comprises: a first magnetic field sensing element arranged in the first track; a first processor that outputs a voltage VM1 when the rotation angle of a first magnetic field applied to the first magnetic field sensing element is less than a first threshold, and that outputs a predetermined high voltage VH when the rotation angle of the first magnetic field is equal to or greater than the first threshold, wherein the voltage VM1 is a voltage between a predetermined low voltage VL and the high voltage VH and indicates the positions of the magnets relative to the first magnetic field sensing element.a second magnetic field detection element arranged in the second track; and a second processor that outputs the low voltage VL when a rotation angle of a second magnetic field applied to the second magnetic field detection element is less than a second threshold, and that outputs the voltage VM2 when the rotation angle of the second magnetic field is equal to or greater than the second threshold, wherein the voltage VM2 is a voltage between the low voltage VL and the high voltage VH and indicates positions of the magnets relative to the second magnetic field detection element.

[0008] According to the present invention, it is possible to provide a position sensor that can detect a position along a long stroke and that can limit an increase in size.

[0009] The above and other items, features and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings, which illustrate examples of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a schematic view showing the arrangement of a vehicle's steering system; Fig. Figures 2A to 2B are views that generally show the arrangement of a position sensor according to an unclaimed comparative form; Fig. 3A to 3B are conceptual views that describe the operating principle of the [system / device]. Fig. 2A to 2B illustrate the position sensor shown; Fig. Figures 4A to 4B are views that generally show the arrangement of a position sensor according to an embodiment of the present invention; Fig. 5A to 5B are conceptual views that describe the operating principle of the Fig. 4A to 4B illustrate the position sensor shown; Fig. Figures 6A to 6B are schematic representations of a first modification of the in Fig. 2A and Fig. Position sensor shown in 2B; Fig. Figures 7A to 7B are schematic representations of a second modification of the in Fig. 2A and Fig. Position sensor shown in 2B; and Fig. Figure 8 is a comparison between a reference example, a comparison example, and an embodiment of the position sensor. DETAILED DESCRIPTION OF THE INVENTION

[0010] With reference to the drawings, embodiments of the present invention are described. In the following descriptions, the first direction is a direction in which the magnetic sensor and the magnet are moved relative to each other and is also referred to as the X-direction. The second direction is a direction perpendicular to the first direction in a plane in which a plurality of magnets are provided (on the substrate 5) and is also referred to as the Y-direction. A direction perpendicular to both the first and second directions is referred to as the Z-direction. A stroke is understood to be the path of movement of the magnet relative to the magnetic sensor in the first direction. The present invention is preferably used, in particular, with a long-stroke position sensor.

[0011] Fig. Figure 1 schematically shows the arrangement of a steering system 100 of a vehicle to which the present invention can preferably be applied. In the steering system 100, one end of the steering shaft 102 is connected to a steering wheel 101, and a pinion 103 is provided at the other end of the steering shaft 102. The pinion 103 engages with a rack 105 of a rod 104 to convert the rotational movement of the steering shaft 102 into a linear movement of the rod 104 in the transverse direction of the vehicle. The rod 104 is connected to a front wheel (not shown). The orientation of the wheel can be changed by the linear movement of the rod 104. The position sensor 1 of the present embodiment detects the position of the rod 104 in the transverse direction of the vehicle.

[0012] Fig. Figure 2A shows the general arrangement of position sensor 1, and Fig. 2B shows a sectional view along line AA in Fig. 2A. In the drawing, the white arrows conceptually indicate the direction of the magnetic flux. The position sensor 1 has a plurality of magnets 2, a magnetic sensor 3, and a sensor output processor 4C, which processes the output signal of the magnetic sensor 3. The magnets 2 are moved in a first direction X relative to the magnetic sensor 3. The sensor output processor 4C can be implemented as a microcomputer or an on-board computer. The magnets 2 are arranged on the rod 104, i.e., a movable element, while the magnetic sensor 3 and the sensor output processor 4C are arranged on the vehicle body 201, i.e., a stationary element. The position sensor 1, the movable element on which the magnets 2 are arranged, and the stationary element on which the magnetic sensor 3 is arranged, form the position sensing system 200.It is also possible to arrange the magnets 2 on the vehicle body 201 and the magnetic sensor 3 on the rod 104. However, to prevent a cable connected to the magnetic sensor 3 from oscillating, the magnetic sensor 3 is preferably arranged on a stationary element. The term "arranging" includes both the direct fastening or connection of an object by means of a screw or adhesive, and the indirect fastening or connection of an object via another element. In the latter case, the movement of the magnets 2 and the movement of the moving element may or may not be completely identical. In other words, it is not necessary for the magnets 2 and the moving element to travel the same path or move along the same route. It is sufficient if the magnets 2 and the moving element move together, so that the movement of the magnets 2 corresponds to the movement of the moving element and vice versa.Alternatively, the magnets 2 can be positioned on one side of the movable element with respect to the direction of movement, so that the position is only detected by a movable element that pushes the magnets 2 when the magnets 2 are moved in a certain direction. For the sake of simplicity, it is assumed in the following descriptions that the magnetic sensor 3 is moved relative to the magnets 2.

[0013] The magnets 2 are arranged on a single substrate 5. The magnets 2 can be arranged individually or in a group on different substrates, but the positional deviation between the magnets 2 can be limited by arranging them on a single substrate 5. The substrate 5 is divided into a first track 5A and a second track 5B, which lie side by side in the second direction Y. One or some of the magnets 2 are arranged on the first track 5A and the others on the second track 5B. The first track 5A and the second track 5B are essentially rectangular or strip-shaped areas that have the same width in the second direction Y. A set of magnets consisting of magnets 2A and 2B is provided on the first track 5, and a set of magnets consisting of the third and fourth magnets 2C and 2D is provided on the second track 5B.The first and second magnets 2A, 2B are arranged in a line on the first track 5A, parallel to the first direction X. The third and fourth magnets 2C, 2D are arranged in a line on the second track 5B, parallel to the first direction X. The back surfaces of the first magnet 2A and the second magnet 2B, facing the magnetic sensor 3, can be connected by a yoke (not shown) extending in the first direction X. Similarly, the back surfaces of the third magnet 2C and the fourth magnet 2D, facing the magnetic sensor 3, can be connected by a yoke (not shown) extending in the first direction X. The area of ​​the first track 5A containing the first and second magnets 2A, 2B is designated as the first magnet area 6A.The area of ​​the second track 5B, in which the third and fourth magnets 2C and 2D are located, is designated as the second magnetic area 6B. This means that one or more of the magnets 2 are located in both the first magnetic area 6A and the second magnetic area 6B. The first magnetic area 6A corresponds to the left half of the first track 5A, and the second magnetic area 6B corresponds to the right half of the second track 5B. The first magnetic area 6A and the second magnetic area 6B have the same length in the first direction X. The magnetic areas of the tracks (first magnetic area 6A and second magnetic area 6B) are defined exclusively with respect to the first direction X, and the magnetic area of ​​each track (first magnetic area 6A and second magnetic area 6B) is continuous with the magnetic area of ​​the other track (second magnetic area 6B and first magnetic area 6A).In particular, the first magnetic area 6A and the second magnetic area 6B do not overlap in the first direction X (or, viewed in the second direction Y), and there is no gap between the first magnetic area 6A and the second magnetic area 6B. In the area where the magnets 2 are arranged, at each position in the first direction X, there is either only the first magnetic area 6A or only the second magnetic area 6B.

[0014] The first through fourth magnets, 2A through 2D, have the same configuration and magnetic properties. The surfaces of the first magnet, 2A, and the second magnet, 2B, facing magnetic sensor 3, have opposite polarities, and the N pole of the first magnet, 2A, and the S pole of the second magnet, 2B, face magnetic sensor 3. Similarly, the surfaces of the third magnet, 2C, and the fourth magnet, 2D, facing magnetic sensor 3, have opposite polarities, and the S pole of the third magnet, 2C, and the N pole of the fourth magnet, 2D, face magnetic sensor 3. That is, two adjacent magnets (second magnet, 2B, and third magnet, 2C) are each located in adjacent magnetic regions (first magnetic region, 6A, and second magnetic region, 6B), and the surfaces of the two adjacent magnets facing magnetic sensor 3 have the same polarity. As shown in Fig. As shown in Figure 2B, the magnetic interference between the second magnet 2B and the third magnet 2C can be limited because the magnetic flux released by the first magnet 2A is mainly absorbed by the second magnet 2B, and the magnetic flux released by the fourth magnet 2D is mainly absorbed by the third magnet 2C. Alternatively, the S-pole of the first magnet 2A and the N-pole of the second magnet 2B can face the magnetic sensor 3, and the N-pole of the third magnet 2C and the S-pole of the fourth magnet 2D can face the magnetic sensor.

[0015] The set of first and second magnets 2A, 2B and the set of third and fourth magnets 2C, 2D are arranged rotationally symmetrically with respect to the contact point 7 of the first magnetic area 6A and the second magnetic area 6B. Since the distribution and intensity of the magnetic field in the first magnetic area 6A and the second magnetic area 6B are approximately the same, the accuracy of the magnetic field detection can be improved. The first to fourth magnets 2A to 2D are spaced from the edges 8 of the first and second magnetic areas 6A, 6B in the first direction X. When the magnets are arranged at the edges 8, larger magnets are required to ensure the magnetic field intensity due to the increased distance between them. In the present embodiment, the length of the first magnetic area 6A and the second magnetic area 6B in the X direction is approximately 100 mm (i.e.,The stroke of position sensor 1 is approximately 200 mm), and the distance D in the X direction between the centers of two magnets in the same magnetic area is approximately 56 mm.

[0016] In the present unclaimed comparative embodiment, two magnets are provided in each track 5A, 5B, but only one magnet can also be provided in each track 5A, 5B. This allows the size of the position sensor 1 to be reduced. Alternatively, three magnets can be provided in each track 5A, 5B. This increases the length of each magnet area in the first direction X and allows the stroke of the position sensor 1 to be increased.

[0017] The magnetic sensor 3 has magnetic field detection elements 9A and 9B for tracks 5A and 5B, respectively. The magnetic sensor 3 has a first magnetic field detection element 9A, which is related to or oriented towards the first track 5A, and a second magnetic field detection element 9B, which is related to or oriented towards the second track 5B. The first magnetic field detection element 9A and the second magnetic field detection element 9B are arranged in a line that runs parallel to the second direction Y. Since the first magnetic field detection element 9A and the second magnetic field detection element 9B are integrated in a single housing, their relative positional deviation can be limited.The first magnetic field detection element 9A and the second magnetic field detection element 9B each contain a magnetic field detection element for the X-direction (not shown), which scans a magnetic field in the X-direction, and a magnetic field detection element for the Z-direction (not shown), which scans a magnetic field in the Z-direction. The magnetic field detection element for the X-direction and the magnetic field detection element for the Z-direction are Hall elements, but could also be magnetic field detection elements of another type, e.g., a TMR element.

[0018] The magnetic sensor 3 further comprises a first processor 4A, which outputs a predetermined voltage based on the angle of the magnetic field detected by the first magnetic field detection element 9A, and a second processor 4B, which outputs a predetermined voltage based on the angle of the magnetic field detected by the second magnetic field detection element 9B. The angle θ of the magnetic field is related to the angle of the magnetic flux in the XZ plane and can be calculated as arctan (Bz / Bx), where Bx is the intensity of the magnetic field in the X direction and Bz is the intensity of the magnetic field in the Z direction. The first processor 4A and the second processor 4B each calculate the angle θ of the magnetic field and output a voltage proportional to the angle θ of the magnetic field. The output voltage can be determined to be proportional to the intensity of the magnetic field Bz in the Z direction.

[0019] When the magnetic sensor 3 is positioned on the left side of tracks 5A and 5B, the first magnetic field detection element 9A overlaps with the first magnetic area 6A, viewed in the Z direction. Since the angle θ of the magnetic field changes as the magnetic sensor 3 moves, the magnetic sensor 3 can detect its position relative to the magnets 2. When the magnetic sensor 3 is positioned on the right side of tracks 5A and 5B, the second magnetic field detection element 9B overlaps with the second magnetic area 6B, viewed in the Z direction. Since the angle θ of the magnetic field changes as the magnetic sensor 3 moves, the magnetic sensor 3 can detect its position relative to the magnets 2. On the other hand, if the first magnetic field detection element 9A overlaps with the first magnetic area 6A, the second magnetic field detection element 9B is located away from the second magnetic area 6B, and the intensity of the detected magnetic field is weak and unstable.If the second magnetic field detection element 9B overlaps with the second magnetic area 6, the first magnetic field detection element 9A is positioned away from the first magnetic area 6A, and the intensity of the detected magnetic field is weak and unstable. A magnetic field applied by a magnet located away from a magnetic field detection element can be considered noise by the magnetic field detection element. Consequently, it is difficult to achieve the measurement accuracy of the position sensor 1 by simply adding the output signal of the first magnetic field detection element 9A and the output signal of the second magnetic field detection element 9B. In the present unclaimed comparative embodiment, the output signal of the first magnetic field detection element 9A and the output signal of the second magnetic field detection element 9B are processed as follows.

[0020] Regardless of the position of the magnetic sensor 3, the first magnetic field detection element 9A and the second magnetic field detection element 9B detect the intensity of the magnetic field Bx in the X-direction and the intensity of the magnetic field Bz in the Z-direction and send them to the first processor 4A and the second processor 4B, respectively. The first processor 4A calculates the first intensity B1 of the magnetic field, which is a vector sum of the intensity of the magnetic field Bx and the intensity of the magnetic field Bz detected by the first magnetic field detection element 9A. Similarly, the second processor 4B calculates the second intensity B2 of the magnetic field, which is a vector sum of the intensity of the magnetic field Bx and the intensity of the magnetic field Bz detected by the second magnetic field detection element 9B. Fig. Figure 3A shows the relationship between the first magnetic field intensity B1, the second magnetic field intensity B2, and the displacement. The first magnetic field intensity B1 is strong in the first magnetic region 6A and weak in the second magnetic region 6B. The second magnetic field intensity B2 is weak in the first magnetic region 6A and very strong in the second magnetic region 6B.

[0021] Fig. Figure 3B shows a method for determining the output signals of the first and second processors 4A and 4B. When the first intensity B1 of the magnetic field is equal to or greater than the predetermined threshold S1, the first processor 4A outputs the first voltage VM1, which is a value between the predetermined low voltage VL and the predetermined high voltage VH, to the sensor output processor 4C, depending on the angle θ of the magnetic field (= arctan (Bz / Bx)). Since the relationship between the angle θ of the magnetic field and the position of the first magnetic field detection element 9A in the X-direction is predetermined, the first processor 4A outputs the first voltage VM1, corresponding to the position of the first magnetic field detection element 9A in the X-direction, to the sensor output processor 4C based on the angle θ of the magnetic field. If the first intensity B1 of the magnetic field is less than the threshold S1, the first processor 4A outputs the high voltage VH.If the first magnetic field intensity B1 is less than the threshold S1, the magnetic sensor 3 is located in the second magnetic area 6B, and the magnetic field intensity detected by the first magnetic field detection element 9A is weak and unstable. Therefore, the output signal of the first processor 4A is fixed to a constant output signal VH.

[0022] On the other hand, the second processor 4B outputs a low voltage VL when the second magnetic field intensity B2 is below the threshold S1. The low voltage VL is a voltage slightly greater than zero, but its value is not limited. When the second magnetic field intensity B2 is less than the threshold S1, the magnetic sensor 3 is located in the first magnetic area 6A, and the magnetic field intensity detected by the second magnetic field sensing element 9B is weak and unstable. Therefore, the output signal of the second processor 4B is fixed at a constant output signal VL. When the second magnetic field intensity B2 is equal to or greater than the threshold S1, the second processor 4B outputs the second voltage VM2, which is a value between the predetermined low voltage VL and the predetermined high voltage VH, to the sensor output processor 4C, depending on the angle θ of the magnetic field.As described above, the relationship between the angle θ of the magnetic field and the position of the second magnetic field detection element 9B in the X direction is determined in advance; the second processor 4B outputs the voltage VM2, which corresponds to the position of the second magnetic field detection element 9B in the X direction, to the sensor output processor 4C, based on the angle θ of the magnetic field.

[0023] The sensor output processor 4C adds the voltage output by the first processor 4A and the voltage output by the second processor 4B, calculates the voltage VT, and outputs it. If the first processor 4A outputs the first voltage VM1 and the second processor 4B outputs the lower voltage VL, then VT = VM1 + VL. If the first processor 4A outputs the voltage VH and the second processor 4B outputs the second voltage VM2, then VT = VH + VM2. The relationship between the position of the magnets 2 relative to the magnetic sensor 3 in the first direction X and the voltage VT is determined in advance. Therefore, the relative position can be determined from the voltage VT output by the sensor output processor 4C. This process can be performed, for example, by another computer mounted on a vehicle.The timing at which the first processor 4A switches the voltage from / to the first voltage VM1 to / from the high voltage VH, and the timing at which the second processor 4B switches the voltage from / to the low voltage VL to / from the second voltage VM2, preferably coincide, but there may be some time delay.

[0024] Fig. 4A, Fig. Figure 4B shows a method for processing the output signal of the first magnetic field detection element 9A and the output signal of the second magnetic field detection element 9B. The first pre-magnetizing magnet 10A is located near the first magnetic field detection element 9A, and the second pre-magnetizing magnet 10B is located near the second magnetic field detection element 9B. The N pole of the first pre-magnetizing magnet 10A is located on the rear (right) side of the first magnetic field detection element 6A, and the S pole faces the first magnetic field detection element 6A (left). The N pole of the second pre-magnetizing magnet 10B is located on the rear (left) side of the second magnetic field detection element 6B, and the S pole faces the second magnetic field detection element 6B (right).As a result, a left-directed magnetic flux is generated near the first premagnetizing magnet 10A and a right-directed magnetic flux near the second premagnetizing magnet 10B. The first magnetic field detection element 9A detects Bx and Bz, and the first processor 4A calculates the first angle θ1 of the magnetic field (= arctan (Bz / Bx)). Similarly, the second magnetic field detection element 9B detects Bx and Bz, and the second processor 4B calculates the second angle θ2 of the magnetic field (= arctan (Bz / Bx)).

[0025] Fig. Figure 5A shows the relationship between the first and second angles θ1, θ2 of the magnetic field and the stroke. The premagnetizing field of the first premagnetizing magnet 10A and the second premagnetizing magnet 10B is weaker than the magnetic field of the first to fourth magnets 2A to 2D. In the first magnet section 6A, the magnetic flux at the left edge is generally directed to the left, while near the first magnet 2A it is generally directed upwards and rotates clockwise to the right. In the region between the left edge of the first magnet section 6A and near the second magnet 2B, the magnetic field of the first and second magnets 2A, 2B dominates, while the magnetic field of the first premagnetizing magnet 10A is negligible in comparison. Conversely, in the region between the second magnet 2B and the third magnet 2C, the magnetic field of the first premagnetizing magnet 10A dominates due to its weak and unstable magnetic field.Consequently, the first angle θ1 of the magnetic field makes approximately one revolution between the left and right edges of the first magnetic region 6A. To the right of this region, i.e., in the region adjacent to the second magnetic region 6B in the Y-direction, the first angle θ1 of the magnetic field is essentially maintained at a constant value by the premagnetizing field of the first premagnetizing magnet 10A. Conversely, in the region adjacent to the first magnetic region 6A in the Y-direction, the second angle θ2 of the magnetic field is essentially maintained at a constant value by the premagnetizing magnetic field of the second premagnetizing magnet 10B, and to the right of this region, i.e., in the second magnetic region 6B, the second angle θ2 of the magnetic field makes approximately one revolution between the left and right edges of the second magnetic region 6B.

[0026] Fig. Figure 5B shows a method for determining the output signals of the first and second processors 4A and 4B. If the first angle θ1 of the magnetic field is smaller than the predetermined first threshold S21, the first processor 4A outputs a first voltage VM1, i.e., a value between the predetermined low voltage VL and the predetermined high voltage VH, to the sensor output processor 4C as a function of the first angle θ1 of the magnetic field. Since the relationship between the first angle θ1 of the magnetic field and the position of the first magnetic field detection element 9A in the X-direction is predetermined, the first processor 4A outputs the first voltage VM1, corresponding to the position of the first magnetic field detection element 9A in the X-direction, to the sensor output processor 4C based on the first angle θ1 of the magnetic field.If the first angle θ1 of the magnetic field is equal to or greater than the first threshold S21, the first processor 4A outputs the high voltage VH. If the first angle θ1 of the magnetic field is equal to or greater than the first threshold S21, the magnetic sensor 3 is located in the second magnetic area 6B, and the intensity of the magnetic field detected by the first magnetic field detection element 9A is weak and unstable. Therefore, the output signal of the first processor 4A is fixed at a constant output signal VH.

[0027] If the second angle θ2 of the magnetic field is smaller than the predefined second threshold S22, the second processor 4B outputs a low voltage VL. When the second angle θ2 of the magnetic field is smaller than the second threshold S22, the magnetic sensor 3 is located in the first magnetic area 6A, and the intensity of the magnetic field detected by the second magnetic field detection element 9B is weak and unstable. Therefore, the output signal of the second processor 4B is fixed at a constant output signal VL. If the second angle θ2 of the magnetic field is equal to or greater than the second threshold S22, the second processor 4B outputs the second voltage VM2, i.e., a value between the predefined low voltage VL and the predefined high voltage VH, to the sensor output processor 4C, depending on the second angle θ2 of the magnetic field.Since, as described above, the relationship between the second angle θ2 of the magnetic field and the position of the second magnetic field detection element 9B in the X direction is determined in advance, the second processor 4B outputs the voltage VM2, which corresponds to the position of the second magnetic field detection element 9B in the X direction, based on the second angle θ2 of the magnetic field, to the sensor output processor 4C.

[0028] The sensor output processor 4C adds the voltage output by the first processor 4A and the voltage output by the second processor 4B to calculate the voltage VT. If the first processor 4A outputs the first voltage VM1 and the second processor 4B outputs the lower voltage VL, then VT = VM1 + VL. If the first processor 4A outputs the voltage VH and the second processor 4B outputs the second voltage VM2, then VT = VH + VM2. The relationship between the position of the magnets 2 relative to the magnetic sensor 3 in the first direction X and the voltage VT is determined in advance. Therefore, the relative position can be determined from the voltage VT output by the sensor output processor 4C.The point in time at which the first processor 4A switches the voltage from / to the first voltage VM1 to / from the high voltage VH, and the point in time at which the second processor 4B switches the voltage from / to the low voltage VL to / from the second voltage VM2, preferably coincide, but there may be a certain time delay. In this embodiment, it is desirable that each track has a sufficient width in the Y direction to mitigate the influence of the magnets in the adjacent track, but the shielding 11, which is described later in the third modification, can alternatively be provided.

[0029] The present invention has been described by the embodiments described above, but the present invention is not limited to the embodiments described above. Some modifications of the present invention will now be described.

[0030] Fig. 6A, Fig. 6B are views similar to the Fig. 2A, Fig. 2B and show the first modification of the in Fig. 2A and Fig. The position sensor shown in Figure 2B is modified. This modification includes a shield 11 extending in a first direction X between the first track 5A and the second track 5B, which are adjacent to each other. The shield 11 is preferably made of a soft magnetic material, such as iron, ferrosilicon, or mu-metal. As described above, the first magnetic field detection element 9A detects a magnetic field generated by the first magnet 2A and the second magnet 2B, but also simultaneously a magnetic field generated by the third magnet 2C and the fourth magnet 2D. In particular, when the magnetic sensor 3 is located near the third magnet 2C, the first magnetic field detection element 9A is further influenced by the magnetic field generated by the third magnet 2C and the fourth magnet 2D.Due to the shielding 11, which blocks the magnetic field, it is possible to reduce the width (the dimension in the second direction Y) of the first track 5A and the second track 5B and thereby reduce the size of the position sensor 1.

[0031] Fig. 7A, Fig. 7B are views similar to the Fig. 2A, Fig. 2B and show the second modification of the in Fig. 2A and Fig. The position sensor shown in Figure 2B is modified. This modification includes a shield 12 arranged between the first magnetic area 6A and the second magnetic area 6B, which are adjacent to each other. The shield 12 extends in the second direction Y across the first track 5A and the second track 5B, which are adjacent to each other. Like the shield 11, the shield 12 is preferably made of a soft magnetic material, such as iron, ferrosilicon, and mu-metal. When the magnetic sensor 3 is arranged, as shown, in the first magnetic area 6A between the second magnet 2B and the third magnet 2C, the first magnetic field detection element 9A can detect a magnetic field generated by the third magnet 2C.Although the magnetic field between the second magnet 2B and the third magnet 2C is weak, a left-directed magnetic flux is generated on the right side of the second magnet 2B, and a right-directed magnetic flux is generated on the left side of the third magnet 2C. This weakens the magnetic flux attracted by the second magnet 2B, and the measurement accuracy can be affected. The shield 12 blocks a magnetic field generated by the third magnet 2C and reduces the influence of the third magnet 2C on the first magnetic field sensing element 9A. Similarly, the shield 12 blocks a magnetic field generated by the second magnet 2B and reduces the influence of the second magnet 2B on the second magnetic field sensing element 9B.

[0032] According to the third modification of the present invention, the sensor output processor 4C can selectively output as voltage VT either the voltage VM1, output by the first processor 4A, or the voltage VM2, output by the second processor 4B. If the first processor 4A outputs the first voltage VM1 and the second processor 4B outputs the low voltage VL, then VT = VM1. If the first processor 4A outputs the voltage VH and the second processor 4B outputs the second voltage VM2, then VT = VM2. The present modification yields the same result as in the case where both VL and VH are zero in the embodiment mentioned above, but it is not necessary to add the output signals.

[0033] Referring to Fig. 3A, Fig. 3B, if the second intensity B2 of the magnetic field is less than the threshold S1, the sensor output processor 4C outputs as VT the first voltage VM1, which is output by the first processor 4A, instead of the sum of VT = VM1 + VL. If the first intensity B1 of the magnetic field is less than the threshold S1, the sensor output processor 4C outputs as VT a second voltage VM2, which is output by the second processor 4B, instead of the sum of VT = VM2 + VH. In this case, the position of the magnets 2 relative to the magnetic sensor 3 cannot be determined solely by the output voltage of the sensor output processor 4C. Accordingly, the sensor output processor 4C preferably continues to output the information selected (as an output signal of the sensor output processor 4C itself) from the output signal of the first processor 4A and the output signal of the second processor 4B.For example, if the output signal of the first processor 4A is selected as the output signal of the sensor output processor 4C, the magnetic sensor 3 in the first magnetic area 6A will be placed in the . Fig. 3A, Fig. 3B is arranged. Therefore, the position of the magnets 2 can be calculated from the output voltage of the sensor output processor 4C. If the magnetic sensor 3 is arranged near the boundary between the first magnetic area 6A and the second magnetic area 6B, it is possible that both conditions B1 <S1 und B2<S1 erfüllt sind. In diesem Fall kann die Bedingung (B1<S1 oder B2<S1), die vorrangig ist, im Voraus bestimmt werden, und das Ausgangssignal kann entsprechend der vorrangigen Bedingung bestimmt werden. Bei der vorliegenden Erfindung gibt der erste Prozessor 4A die Hochspannung VH aus, wenn beide Bedingungen B1<S1 und B2<S1 erfüllt sind, und der zweite Prozessor 4B gibt VL aus. Wenn die Bedingung B1<S1 vorrangig ist, kann der Sensorausgangsprozessor 4C das Ausgangssignal VH des ersten Prozessors 4A als das Ausgangssignal des Sensorausgangsprozessors 4C auswählen.If condition B2 <S1 vorrangig ist, kann der Sensorausgangsprozessor 4C das Ausgangssignal VL des zweiten Prozessors 4B als Ausgangssignal des Sensorausgangsprozessors 4C auswählen. Wenn entweder die Bedingung B1<S1 oder B2<S1 erfüllt ist, wird der oben beschriebene Prozess durchgeführt. Das heißt, die Spannung, die vom Sensorausgangsprozessor 4C ausgegeben wird, ist nicht auf VM1 und VM2 beschränkt und kann das Ausgangssignal des ersten Prozessors 4A oder des zweiten Prozessors 4B sein.

[0034] Referring to Fig. 5A, Fig. 5B, if the second angle θ2 of the magnetic field is less than the second threshold S22, the sensor output processor 4C outputs as VT the first voltage VM1 output by the first processor 4A, instead of summing VT=VM1+V. If the first angle θ1 of the magnetic field is equal to or greater than the first threshold S21, the sensor output processor 4C outputs as VT the second voltage VM2 output by the second processor 4B, instead of summing VT=VM2+VH. In this case, as with reference to Fig. 3A, Fig. As described in 3B, the sensor output processor 4C preferably continues to output the information about the voltage (as the output signal of the sensor output processor 4C itself) assumed to be derived from the output signal of the first processor 4A and the output signal of the second processor 4B. If the magnetic sensor 3 is located near the boundary between the first magnetic area 6A and the second magnetic area 6B, it is possible that both conditions B1 <S1 und B2<S1 erfüllt sind. In diesem Fall kann, wie unter Bezugnahme auf Fig. 3A, Fig. As described in 3B, the condition that takes precedence can be determined in advance, and the output signal can be determined according to the precedence condition.

[0035] As described above, it can be determined whether the magnetic sensor 3 is located in the first magnetic area 6A or in the second magnetic area 6B, based on the information about which output signal from the first processor 4A and the second processor 4B is selected by the sensor output processor 4C (as the output signal of the sensor output processor 4C itself). Thus, the position of the magnets 2 in the first direction X relative to the magnetic sensor 3 can be determined from the output signal VT. Since summing the output signals is not required in this modification, the sensor output processor 4C can be simplified.

[0036] Finally, the present embodiment is compared with a comparative example. Fig. Figure 8 shows a comparison between position sensors of a reference example, a comparison example, and an unclaimed comparative form referred to as the "Example." The reference example is an example of a conventional short-stroke position sensor. The number of tracks is one, and the stroke is 24 mm. Three magnets are provided, located at both ends and in the center of the substrate. The comparison example and the Example are examples of a long-stroke position sensor. The stroke is 200 mm, which is about eight times greater than that of the reference example. The comparison example has a single-track configuration like the reference example, and the number and arrangement of the magnets are also the same as in the reference example. Large magnets are required to generate a strong magnetic field over a large distance D between the centers of the magnets.The total volume of the magnets increases significantly with increasing stroke rate and is approximately 60 times larger than that of the reference example. The height (dimension in the Z-direction) of the magnets is approximately four times greater than that of the reference example. To efficiently apply a magnetic field to the magnetic sensor, the distance between the magnets and the magnetic sensor in the Z-direction is increased at approximately the same rate as the stroke rate compared to the reference example. Therefore, the cost of the comparison example is higher than that of the reference example, and the installation space is significantly increased. Furthermore, the increased magnet size leads to an increase in the magnet's magnetic force. This may result in a decrease in position detection accuracy, as metals such as iron powder readily adhere to the magnet, and may also complicate the installation of the position sensor in a vehicle.Furthermore, the surrounding magnetic elements tend to be affected by the magnets of the position sensor.

[0037] The example corresponds to the one in Fig. The unclaimed comparative form shown is used. Due to the two-track configuration, the distance D between the centers of the magnets in the example is approximately half the distance D in the comparative example. Accordingly, it is not necessary to use magnets as large as in the comparative example. The number of magnets is increased, but the total volume of the magnets is less than 20% of that in the comparative example. The distance between the magnets and the magnetic sensor is approximately half the distance in the comparative example.

[0038] Although a particular preferred embodiment of the present invention has been shown and described in detail, it should be understood that various changes and modifications may be made without departing from the spirit or scope of the attached claims.

Claims

A position sensor (1) comprising: a magnetic sensor (3);a plurality of magnets (2) which are moved in a first direction (X) relative to the magnetic sensor (3), wherein one or some of the magnets (2) are arranged in a first track (5A) and the remaining magnets (2) are arranged in a second track (5B), the magnetic sensor (3) comprising: a first magnetic field detection element (9A) arranged in the first track (5A), a first processor (4A) which outputs a voltage VM1 when a rotation angle of a first magnetic field applied to the first magnetic field detection element (9A) is less than a first threshold (S21), and which outputs a predetermined high voltage VH when the rotation angle of the first magnetic field is equal to or greater than the first threshold (S21), wherein the voltage VM1 is a voltage between a predetermined low voltage VL and the high voltage VH and indicates positions of the magnets (2) relative to the first magnetic field detection element (9A);a second magnetic field detection element (9B) arranged in the second track (5B); and a second processor (4B) which outputs the low voltage VL when a rotation angle of a second magnetic field applied to the second magnetic field detection element (9B) is less than a second threshold (S22), and which outputs a voltage VM2 when the rotation angle of the second magnetic field is equal to or greater than the second threshold (S22), wherein the voltage VM2 is a voltage between the low voltage VL and the high voltage VH and indicates positions of the magnets (2) relative to the second magnetic field detection element (9B). The position sensor (1) according to claim 1, further comprising a sensor output processor (4C) which processes the output signal of the magnetic sensor (3), wherein the sensor output processor (4C) calculates a sum of the output signal of the first processor (4A) and the output signal of the second processor (4B). The position sensor (1) according to one of claims 1 or 2, wherein the first processor (4A) calculates the rotation angle of the first magnetic field based on a magnetic field detected by the first magnetic field detection element (9A), and the second processor (4B) calculates the rotation angle of the second magnetic field based on a magnetic field detected by the second magnetic field detection element (9B). The position sensor (1) according to claim 1, wherein the first processor (4A) calculates the voltage VM1 based on the rotation angle of the first magnetic field, and the second processor (4B) calculates the voltage VM2 based on the rotation angle of the second magnetic field. The position sensor (1) according to claim 1, wherein one or some of the magnets (2) are arranged in a first magnetic area (6A) of the first track (5A), and the remaining magnets (2) are arranged in a second magnetic area (6B) of the second track (5B). The position sensor (1) according to claim 5, wherein the magnetic sensor (3) comprises: a first pre-magnetizing magnet (10A) which applies a magnetic field to the first magnetic field detection element (9A), wherein the magnetic field is directed in a direction opposite to a direction of a magnetic field at a center of the first magnetic area (6A), and a second pre-magnetizing magnet (10B) which applies a magnetic field to the second magnetic field detection element (9B), wherein the magnetic field is directed in a direction opposite to a direction of a magnetic field at a center of the second magnetic area (6B). The position sensor (1) according to claim 5, wherein the first magnetic area (6A) and the second magnetic area (6B) are provided exclusively and continuously in the first direction (X). The position sensor (1) according to claim 5, wherein surfaces of a pair of adjacent magnets (2) have the same polarity, the surfaces facing the magnetic sensor (3) and one of the pair of magnets (2) is arranged in the first magnetic area (6A) and the other in the second magnetic area (6B). The position sensor (1) according to claim 5, wherein each magnet (2) is spaced apart from the edges (8) of the first and second magnet area (6A, 6B) in the first direction (X). The position sensor (1) according to claim 5, further comprising a shield (12) extending between the first magnetic area (6A) and the second magnetic area (6B), wherein the shield (12) extends over the first and the second track (5A, 5B) in a direction (Y) perpendicular to the first direction (X). The position sensor (1) according to claim 1, which further comprises a shield (11) extending in the first direction (X) between the first track (5A) and the second track (5B). The position sensor (1) according to claim 5, wherein a magnet (2) is arranged in the first magnetic area (6A) and in the second magnetic area (6B). The position sensor (1) according to claim 5, wherein two magnets (2) are arranged in the first magnetic area (6A) and in the second magnetic area (6B). The position sensor (1) according to claim 5, wherein three magnets (2) are arranged in the first magnetic area (6A) and in the second magnetic area (6B). The position sensor (1) according to claim 5, wherein a set of magnets (2) arranged in the first magnetic area (6A) and a set of magnets (2) arranged in the second magnetic area (6B) are rotationally symmetric with respect to a contact point (7) of the first magnetic area (6A) and the second magnetic area (6B). The position sensor (1) according to one of claims 1 to 15, wherein the magnets (2) are arranged on a substrate (5). A position detection system (200) comprising: the position sensor (1) according to any one of claims 1 to 15; a movable element (104) to which the magnets (2) are attached; and a stationary element (201) to which the magnetic sensor (3) is attached. A steering system (100) with the position detection system (200) according to claim 17.

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