Magnetic detection device, magnetic detection module, magnetic detection system, gear drive detection device, motor drive detection device, and encoder

Abstract

The invention provides a magnetic detection device, a magnetic detection module, a magnetic detection system, a gear drive detection device, a motor drive detection device, and an encoder which have a small number of components and can be compactly configured. This magnetic detection device is provided with: a first detection unit that detects a change in magnetic force from a magnet, which is generated by a first convex row comprising at least one convex part provided on a moving body passing between the first detection unit and the magnet in accordance with the movement of the moving body; a magnet; and a second detection unit that are arranged in this order in one direction. The second detection unit detects a change in magnetic force from the magnet generated by a second convex row comprising at least one convex portion provided on the moving body passing between the magnet and the second detection unit in accordance with the movement of the moving body.

Description

Technical Field

[0001] The invention relates to a magnetic detection device, a magnetic detection module, a magnetic detection system, a gear drive detection device, a motor drive detection device and an encoder. Background Art

[0002] Various detection devices are known for detecting the rotation angle of a rotating body or the displacement position of a linear motion body. Among these detection devices, magnetic detection devices are widely used due to their ability to contactlessly detect the angle and position of a moving object, even in environments with high levels of interference light and dust, which can hinder sensing. For example, they are used as rotation angle detection devices for internal combustion engines (see, for example, Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 61-177794 Summary of the Invention

[0006] When detecting the rotation angle of a rotating body or the displacement position of a linear body, it is sometimes necessary to detect the absolute rotation angle or displacement position relative to a measurement reference, rather than the relative rotation angle (i.e., the amount of rotation) or displacement position (i.e., the amount of displacement). In such cases, a detection unit for detecting the measurement reference provided on the moving body is typically provided separately from the detection unit for detecting the relative rotation angle or displacement position. However, considering the various environments in which magnetic detection devices are used, it is desirable to minimize the number of components and achieve a compact design.

[0007] The present invention is made to solve such problems and provides a magnetic detection device having a small number of components and capable of being compactly constructed, and a magnetic detection module, a magnetic detection system, a gear drive detection device, and a motor drive detection device including the magnetic detection device.

[0008] The magnetic detection device of the first aspect of the present invention comprises a first detection unit, a magnet, and a second detection unit arranged in sequence along one direction, the first detection unit detecting a change in the magnetic force from the magnet caused by a first convex row composed of at least one convex portion provided on a movable body passing between the first detection unit and the magnet as the movable body moves, and the second detection unit detecting a change in the magnetic force from the magnet caused by a second convex row composed of at least one convex portion provided on the movable body passing between the magnet and the second detection unit as the movable body moves.

[0009] Furthermore, a magnetic detection module according to a second aspect of the present invention includes the magnetic detection device described above, and a base member for positioning the first detection portion, the magnet, and the second detection portion of the magnetic detection device.

[0010] Furthermore, a magnetic detection system according to a third aspect of the present invention includes the magnetic detection device described above together with the movable body described above.

[0011] Furthermore, a gear drive detection device according to a fourth aspect of the present invention includes the above-mentioned magnetic detection system.

[0012] Furthermore, a motor drive detection device according to a fifth aspect of the present invention includes the above-mentioned magnetic detection system.

[0013] Furthermore, an encoder according to a sixth aspect of the present invention includes the above-mentioned magnetic detection system.

[0014] According to the present invention, it is possible to provide a magnetic detection device having a small number of components and capable of being compactly configured, and a magnetic detection module, a magnetic detection system, a gear drive detection device, and a motor drive detection device including the magnetic detection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is an overall diagram showing the overall structure of the magnetic detection system of the first embodiment.

[0016] Figure 2 This is a partial perspective view showing an enlarged view of the main parts of the magnetic detection system.

[0017] Figure 3 This is an enlarged view of the main parts for explaining the configuration and function of the magnetic detection device.

[0018] Figure 4 It is a diagram showing changes in the output of each sensor accompanying the rotation of the rotating body.

[0019] Figure 5 It is a diagram for explaining the relationship between the interval between adjacent first convex portions and the width of the first convex portions.

[0020] Figure 6 Graph showing simulation results of the detection magnetic flux distribution with respect to the tooth width ratio.

[0021] Figure 7 This is a diagram for explaining the difference in the output of the third sensor due to the presence or absence of the yoke.

[0022] Figure 8 It is an overall diagram showing the overall structure of the magnetic detection system according to the second embodiment.

[0023] Explanation of symbols

[0024] 10, 20…Magnetic detection system, 100…Magnetic detection module, 110…Frame, 120…Mounting portion, 130…Connector insertion port, 141…First slit, 142…Second slit, 150…Magnet, 151…Yoke, 151a…Opening, 160…First detection portion, 161…First sensor, 162…Second sensor, 170…Second detection portion (third sensor), 200…Rotating body, 210…Circular plate portion, 220…Joint portion, 230…First protrusion, 240…Second protrusion, 300…Direct-acting body, 310…Plate portion, 320…Joint portion, 330…First protrusion, 340…Second protrusion, 910…Rotating shaft, 920…Reciprocating slider. DETAILED DESCRIPTION

[0025] Embodiments of the present invention will be described with reference to the accompanying drawings. In each figure, components labeled with the same reference numerals have the same or similar structure. Furthermore, in each figure, when there are multiple structures having the same or similar structure, in order to avoid complexity, some components may be labeled with reference numerals while the other components may be omitted from the same reference numerals. Furthermore, the present invention is not limited to the following embodiments. Furthermore, not all of the structures described in the embodiments are necessarily required as technical means for solving the technical problem.

[0026] Figure 1 1 is an overall diagram showing the overall configuration of a magnetic detection system 10 according to a first example of the present embodiment. The magnetic detection system 10 includes a rotating body 200 fixed to a rotating shaft 910 and a magnetic detection module 100 for detecting the rotation angle of the rotating body 200 .

[0027] The rotating body 200 mainly comprises a circular plate portion 210, a joint portion 220, a first protrusion 230, and a second protrusion 240. The rotating body 200 is formed entirely from a plate-shaped soft magnetic material. Specifically, the joint portion 220, the first protrusion 230, and the second protrusion 240 are manufactured by punching or bending.

[0028] The circular plate portion 210 serves as a base material of the rotating body 200. The circular plate portion 210 may also be subjected to weight reduction processing, for example, in the radial direction. The joint portion 220 serves as a mounting portion for mounting on the rotating shaft 910. The joint portion 220 may be riveted to the rotating shaft 910 or may be mounted via a loading and unloading mechanism. The rotating body 200 is mounted on the rotating shaft 910 via the joint portion 220 and rotates integrally with the rotating shaft 910. In addition, in this embodiment, it is assumed that the rotating shaft 910 can rotate in a clockwise direction (CW) as shown in the figure, or can rotate in a counterclockwise direction (CCW) for illustration.

[0029] Multiple first protrusions 230 are provided along the circumferential direction of the periphery of the circular plate portion 210. Specifically, each first protrusion 230 is formed by bending the tongues radially arranged on the periphery of the circular plate portion 210 so as to stand upright relative to the plane of the circular plate portion 210. The width direction of the first protrusions 230 thus formed is along the circumferential direction of the circular plate portion 210. In this embodiment, a case where 30 first protrusions 230 are formed at equal intervals along the periphery of the circular plate portion 210 is used as an example for description. These first protrusions 230 standing upright along the circumferential direction constitute a first protrusion row as a whole.

[0030] The second protrusion 240 is formed by punching and bending the tongue piece in a manner that is upright relative to the plane of the circular plate portion 210, similar to the first protrusion 230. The width direction of the second protrusion 240 is the same as the width direction of the first protrusion 230, and is along the circumferential direction of the circular plate portion 210. As described later, multiple second protrusions 240 can also be provided along concentric circles. However, in this embodiment, a case where a second protrusion 240 is formed on the inner circumferential side of the circumference of the circular plate portion 210 is used as an example for description. The one or more second protrusions 240 formed in this way constitute the second protrusion row as a whole.

[0031] The magnetic detection module 100 is mounted and fixed to a support (not shown) via a mounting portion 120. The frame 110 of the magnetic detection module 100 serves as a base member for positioning various components of the magnetic detection device described later. The magnetic detection device, mounted on the frame 110, detects the first protrusions 230 of the first protrusion row and the second protrusions 240 of the second protrusion row, which move relative to the magnetic detection module 100, based on changes in magnetic force.

[0032] In addition, in this embodiment, as shown in the coordinate axis in the figure, the rotation axis direction of the rotation axis 910 is determined as the Z axis direction, and the two axes orthogonal to the Z axis direction are determined as the X axis direction and the Y axis direction. Figure 1 The same coordinate axes based on the state of the magnetic detection system 10 are set as described above, and the orientations of the structures shown in the respective drawings are indicated.

[0033] Figure 2 This is a partial perspective view showing an enlarged main portion of the magnetic detection system 10. The housing 110 of the magnetic detection module 100 supports various elements of the magnetic detection device, and output signals from a magnetic sensor (described later) are output to a signal processing circuit via a connector (not shown) inserted into a connector insertion port 130 .

[0034] The housing 110 includes a first slit 141 and a second slit 142. The first slit 141 is a space through which the rotating first protrusion 230 passes. The second slit 142 is a space through which the similarly rotating second protrusion 240 passes. While details will be described later, the magnetic sensor detects the magnetic force that changes as the first protrusion 230 passes through the first slit 141 and the magnetic force that changes as the second protrusion 240 passes through the second slit.

[0035] Figure 3 This is an enlarged view of the main part for explaining the configuration and function of the magnetic detection device. The magnetic detection device has a rotation center S passing through the rotating body 200. a The first detection unit 160, the magnet 150, the yoke 151, and the second detection unit 170 are arranged along a straight line parallel to the Y axis (indicated by a single dotted line in the figure). In this embodiment, the first detection unit 160 is composed of a first sensor 161 and a second sensor 162, which are arranged along the moving direction of the first protrusion 230 in a manner that sandwiches the straight line. The first detection unit 160, the magnet 150, the yoke 151, and the second detection unit 170 are supported and fixed to Figure 1 and Figure 2 The positions of the frames 110 are determined respectively. Figure 3 In FIG, the frame 110 is omitted except for the dotted lines indicating the space of the first slit 141 and the space of the second slit 142 .

[0036] The first sensor 161 and the second sensor 162 that comprise the first detection unit 160 are both magnetic sensors, such as linear Hall effect ICs. As the rotating body 200 rotates, the first protrusion 230 passes through the first slit 141 defined between the first and second sensors 161, 162, and the magnet 150. While details will be provided later, when the first protrusion 230 passes through the first slit 141, the magnetic force from the magnet 150 is temporarily blocked. Consequently, the first and second sensors 161, 162 each output an analog signal corresponding to the passage of the first protrusion 230.

[0037] In this embodiment, second detection unit 170 is comprised of a single magnetic sensor and is therefore referred to herein as third sensor 170. Third sensor 170 is, for example, a switch-type Hall effect IC. As rotating body 200 rotates, second protrusion 240 passes through second slit 142 defined between magnet 150 and third sensor 170. While this will be described in detail later, when second protrusion 240 passes through second slit 142, the magnetic force from magnet 150 is temporarily blocked. Consequently, third sensor 170 outputs a binary signal (digital signal) corresponding to the passage of second protrusion 240.

[0038] Magnet 150 is a permanent magnet. In this embodiment, because a Hall effect IC is used as a magnetic sensor, its magnetization direction is parallel to the direction indicated by the dashed line. A yoke 151 is positioned adjacent to the surface of magnet 150 facing third sensor 170, limiting the magnetic force from magnet 150 toward third sensor 170. Yoke 151 has an opening 151a near its center, which contributes to limiting the magnetic force from magnet 150 toward third sensor 170. The specific functions of yoke 151 and opening 151a will be described later.

[0039] Figure 4 1 is a diagram showing changes in the output of each sensor accompanying the rotation of the rotating body 200 . Figure 4 The figure above shows the analog signal outputs of each sensor when rotating body 200 rotates counterclockwise (CCW), specifically before and after second protrusion 240 passes through second slit 142. The horizontal axis represents the rotation angle (deg), and the vertical axis represents the detected magnetic flux density (T). The solid line L1 represents the output of first sensor 161, the dashed line L2 represents the output of second sensor 162, and the dashed line S represents the output of third sensor 170 during the analog phase.

[0040] The output of first sensor 161 decreases as first protrusion 230 approaches the area between first sensor 161 and magnet 150, and increases as first protrusion 230 moves away from the area between first sensor 161 and magnet 150. When a first protrusion 230 passes, its output signal forms a roughly sinusoidal curve corresponding to one wavelength, and this increase and decrease repeats each time a first protrusion 230 passes. In other words, if the rotational speed of rotating body 200 is constant, the output of first sensor 161 becomes a roughly sinusoidal signal with a constant period. Furthermore, the interval C in the bottom-to-bottom diagram of the output represents the rotation angle corresponding to adjacent first protrusions 230. In this embodiment, as described above, 30 first protrusions 230 are provided along the circumference of circular plate portion 210, corresponding to 12°.

[0041] The output of second sensor 162 is also identical to the output of first sensor 161. Specifically, it decreases as first protrusion 230 approaches the area between second sensor 162 and magnet 150 and increases as first protrusion 230 moves away from the area between second sensor 162 and magnet 150. Second sensor 162 is spaced apart from first sensor 161 along the direction of movement of first protrusion 230. Therefore, when rotating body 200 rotates counterclockwise, as shown in the figure, the output of second sensor 162 exhibits a delayed change that follows the output of first sensor 161. Conversely, when rotating body 200 rotates clockwise, the output of first sensor 161 exhibits a delayed change that follows the output of second sensor 162. Therefore, if first detection unit 160 is composed of two sensors (first sensor 161 and second sensor 162) arranged along the direction of movement of first protrusion 230, as in this embodiment, the rotational direction of rotating body 200 can be detected by observing the changes in their respective outputs.

[0042] In this embodiment, a plurality of first protrusions 230 are provided at regular intervals along the periphery of the circular plate portion 210. Therefore, the outputs of the first sensor 161 and the second sensor 162 each exhibit periodic fluctuations as described above. On the other hand, as described above, a single second protrusion 240 is provided slightly inward from the periphery of the circular plate portion 210. Therefore, the internal analog signal of the third sensor 170 is constant when the second protrusion 240 is sufficiently away from the third sensor 170, decreasing as the second protrusion 240 approaches the area between the magnet 150 and the third sensor 170, increasing as the second protrusion 240 leaves the area between the magnet 150 and the third sensor 170, and returning to a constant output fluctuation.

[0043] As described above, the third sensor 170 is a switch type IC. When the value of the internal analog signal is lower than the threshold value Th1, the Figure 4 As shown in the figure below, the binary output of IC is from V low Switch to V high When the internal analog signal value returns to the threshold Th2, the IC's binary output changes from V high Switch to V low The signal processing circuit can, for example, convert the binary output of the IC from V low Switch to V high The posture of rotating object 200 at the time of measurement is determined as the measurement reference (for example, rotation angle = 0°). Then, by observing the changes in the outputs from first sensor 161 and second sensor 162 at this reference time, the rotation angle of rotating object 200 from the measurement reference can be calculated. In other words, the posture of rotating object 200 at the measurement time can be identified.

[0044] Furthermore, the above description describes a case where the outputs of first sensor 161 and second sensor 162 depict a roughly sinusoidal curve. If the outputs depict a sinusoidal curve, the rotation angle between two adjacent first protrusions 230 at a given point in time can also be calculated using an inverse trigonometric function. Therefore, to measure the rotation angle of rotating body 200 as a continuous value, the output of at least one of first sensor 161 and second sensor 162 must depict a sinusoidal curve. However, to achieve a sinusoidal output, adjustments must be made to the positions of magnet 150, first sensor 161, and second sensor 162, and the shape of first protrusion 230 must also be considered.

[0045] Figure 5 This is a diagram for explaining the relationship between the interval between adjacent first convex portions 230 and the width of the first convex portion 230. As shown in the figure, the interval between adjacent first convex portions 230 is set to the rotation center S of the rotating body 200. a The angle formed by the connected diameters is C S In this embodiment, 30 first protrusions 230 are provided along the periphery of the circular plate portion 210. Therefore, C S = 12°. In addition, the width of the first convex portion 230 is connected to the two ends and the rotation center S a The angle formed by the diameters is set as C W Therefore, the ratio R of the width of the first convex portion 230 to the interval between two adjacent first convex portions 230 is c Can R c =C W / C S definition.

[0046] In R c When the value is small, the first sensor 161 is not blocked by the first protrusion 230 and directly receives the magnetic force of the magnet 150 for a longer period of time. Figure 4 The output curve of the first sensor 161, i.e., the solid line L1, has a flat portion at the maximum value. c When the first sensor 161 is blocked by the first protrusion 230, the period during which the first sensor 161 directly receives the magnetic force of the magnet 150 becomes longer, and the period during which the first sensor 161 directly receives the magnetic force of the magnet 150 becomes shorter. Figure 4 The output curve of the first sensor 161 shown, that is, the valley shape including the minimum value of the solid line L1, becomes shallower and smaller. The output of the second sensor 162 is also the same. That is, when R c If the range is not appropriate, the sensor output will not be able to draw a sine wave curve.

[0047] As a result of trial and error conducted by the inventors, it was found that in R c When the value is 8% or more and 40% or less, it is easy to adjust the sensor output to a sine wave curve. Figure 6 It represents the tooth width ratio (R c ) is a diagram showing the simulation results of the detection magnetic flux distribution. The horizontal axis represents the rotation angle (deg) and the vertical axis represents the detection magnetic flux density (T). As shown in the figure, each curve represents R c The changes when R is 5%, 8%, 20%, 30%, 40%, 50%, and 75%. c When the value is between 8% and 40%, it is roughly treated as a sine wave. In particular, since the waveform of 20% is highly consistent with the sine wave, it can be said that R c For example, the range of 10% to 30% is preferable. c By adjusting the first convex portion 230 , i.e., the first convex row, within such a range, the arrangement of the magnet 150 and each sensor can be adjusted relatively simply. As a result, each sensor can output a curve that is at least close to a sine wave curve.

[0048] The second slit 142 is provided closer to the rotation center S than the position where the magnet 150 is arranged. a The third sensor 170 is also arranged at the rotation center S a Therefore, the area where third sensor 170 can be placed is often restricted. While magnet 150 should be optimally positioned to obtain an appropriate output, as with first sensor 161 and second sensor 162, this optimal placement is difficult for third sensor 170. Therefore, in this embodiment, yoke 151 is positioned adjacent to the surface of magnet 150 facing third sensor 170, enabling an appropriate output to be obtained even when third sensor 170 is placed in a restricted area. Magnetic yoke 151 serves to adjust the magnetic force from magnet 150 toward third sensor 170.

[0049] Figure 7 This graph illustrates the difference in the output of third sensor 170 depending on the presence or absence of yoke 151. The horizontal axis represents the rotation angle (deg), and the vertical axis represents the detected magnetic flux density (T). The solid line represents the simulated output of third sensor 170 without yoke 151, while the dashed-dotted line represents the simulated output of third sensor 170 with yoke 151.

[0050] In most cases, the third sensor 170 is placed in a region close to the magnet 150. If the third sensor 170 is placed in a region close to the magnet 150, the magnetic detection module 100 as a whole can be made smaller. However, if this is done, as shown by the solid line, the magnetic flux density detected by the third sensor 170 increases as a whole, and the amount of reduction (D shown in the figure) when the second protrusion 240 passes by increases. n) is also insufficient, resulting in a flat portion near the valley bottom.

[0051] On the other hand, even if the third sensor 170 is arranged at the same position, if the yoke 151 is provided, as shown by the single-dot chain line, the magnetic flux density detected by the third sensor 170 becomes slightly smaller as a whole, and a decrease is formed when the second protrusion 240 passes (D e ) large V-shaped valley. In particular, in this embodiment, the opening portion 151a is provided in the yoke 151, so the amount D is reduced. e That is, the magnetic flux density detected when the second protrusion 240 passes through changes more. When the magnetic flux density detected changes greatly, the magnetic flux density changes from V low Switch to V high The timing is more stable and the measurement reference can be detected with higher accuracy.

[0052] The size of the opening 151a provided in the yoke 151 is appropriately determined based on the magnetic force of the magnet 150 and the configuration position of the third sensor 170. In some cases, the opening 151a may not be provided depending on these conditions. The opening 151a may be formed in a slit shape relative to the yoke 151 (for example, the yoke 151 is composed of two independent parts with a gap between them). In addition, the yoke 151 may be formed in a U-shape. That is, the yoke 151 only needs to be configured so as not to cover a portion of the magnet 150. In addition, in this embodiment, the yoke 151 is arranged adjacent to the surface of the magnet 150 on the side of the third sensor 170, but it may also be arranged adjacent to the sensor-side surfaces of the magnet 150 and the first sensor 161 and the second sensor 162, depending on the relationship between the magnet 150 and the first sensor 161 and the second sensor 162. In this case, two openings 151a may be provided, corresponding to each of the first sensor 161 and the second sensor 162.

[0053] Next, a second example of this embodiment will be described. Figure 8 : is an overall diagram showing the overall structure of the magnetic detection system 20 of the second embodiment. In the magnetic detection system 10 of the first embodiment, the detection target of the magnetic detection module 100, that is, the moving object, is the rotating object 200. In other words, the magnetic detection system 10 is a system that detects the rotation angle of the rotating object 200 and the rotation axis 910. In the magnetic detection system 20 of the second embodiment, the detection target of the magnetic detection module 100, that is, the moving object, is, for example, a rotating object in the horizontal direction ( Figure 8 A linear motion body 300 reciprocates in the X-axis direction.

[0054] The magnetic detection system 20 is composed of a linear motion body 300 fixedly mounted on a reciprocating slider 920 and a magnetic detection module 100. In this embodiment, the magnetic detection module 100 detects the displacement position of the linear motion body 300 and, therefore, the reciprocating slider 920.

[0055] The linear actuator 300 mainly comprises a flat plate portion 310, a joint portion 320, a first protrusion 330, and a second protrusion 340. The linear actuator 300 is formed entirely from a plate-shaped soft magnetic material. Specifically, the joint portion 320, the first protrusion 330, and the second protrusion 340 are manufactured by punching or bending.

[0056] The flat plate portion 310 serves as the base material of the linear motion body 300. The joint portion 320 serves as a mounting portion for attachment to the reciprocating slider 920. The linear motion body 300 is attached to the reciprocating slider 920 via the joint portion 320, thereby linearly moving integrally with the reciprocating slider 920. In this embodiment, the reciprocating slider 920 is described as reciprocating in the rightward (R) and leftward (L) directions as shown.

[0057] Multiple first protrusions 330 are provided along a side edge of the flat plate portion 310 along the linear motion direction. Specifically, each first protrusion 330 is formed by bending tongues arranged in a comb-like pattern on the side edge of the flat plate portion 310 so that they stand upright relative to the plane of the flat plate portion 310. The width direction of the first protrusions 330 formed in this manner is along the longitudinal direction (linear motion direction) of the flat plate portion 310. These first protrusions 330 standing along the longitudinal direction collectively constitute a first protrusion row.

[0058] The second protrusion 340 is formed by punching a tongue formed inwardly of the side edge of the flat plate portion 310, where the first protrusion 330 is located, and is bent so that it stands upright relative to the plane of the flat plate portion 310, similar to the first protrusion 330. Like the width direction of the first protrusion 330, the width direction of the second protrusion 340 is along the longitudinal direction of the flat plate portion 310. While multiple second protrusions 340 may be provided along the longitudinal direction, in this embodiment, a single second protrusion 340 is formed inwardly of the side edge of the flat plate portion 310. The one or more second protrusions 340 formed in this manner collectively constitute a second protrusion row.

[0059] The structure of the magnetic detection module 100 is the same as that of the magnetic detection module 100 of the first embodiment. In the magnetic detection system 20 thus configured, the first sensor 161 and the second sensor 162 detect the first protrusions 330 passing through the first slit 141, and the third sensor 170 detects the second protrusions 340 passing through the second slit 142. More specifically, the first and second sensors 161 and 162 detect the displacement of the linear motion body 300 by detecting the first protrusions 330 arranged at regular intervals, while the third sensor 170 detects the reference position of the linear motion body 300 by detecting the second protrusions 340. The signal processing circuit can calculate the absolute position of the linear motion body 300 based on these detection results.

[0060] The first and second embodiments described above can be modified in various ways. For example, the convex portions are not limited to those of bent plate-like components. They can also be constructed as separate parts from the circular plate portion or the flat plate portion, i.e., the substrate portion, and mounted on the substrate portion. Furthermore, the substrate portion can be divided into a first substrate portion having a first convex row and a second substrate portion having a second convex row, which can be positioned relative to each other and mounted on a driven object such as the rotating shaft 910 or the reciprocating slider 920. In this case, the substrate portion can also be other than a soft magnetic material. Furthermore, the magnetic sensor can also be other than a Hall IC. For example, an MR element can be used. In this case, the magnetization direction of the magnet can be changed according to the magnetic sensor used.

[0061] In the first and second embodiments described above, a single second protrusion constitutes the second protrusion row. However, if multiple reference positions are to be detected, the number of second protrusions can be increased accordingly. Furthermore, while the first protrusion row is arranged at the edge and the second protrusion row is arranged within the base portion of the movable body, these arrangements may be reversed.

[0062] In addition, in the first and second embodiments described above, an example in which the first detection unit 160 is composed of two sensors (the first sensor 161 and the second sensor 162) is described, but in cases where there is no need to detect the moving direction of the moving body, it can also be composed of a single sensor. In this case, as in the first and second embodiments, it is preferred to configure the first detection unit, the magnet, and the second detection unit along a direction orthogonal to the moving direction of the moving body. In addition, the "orthogonal" mentioned here is not strictly limited to the case of 90°. As mentioned above, it is sufficient as long as the first detection unit and the second detection unit are within the range that can detect the magnetic force of the magnet. If configured in this way, the magnetic detection device and the magnetic detection module including the magnetic detection device can be compactly constructed. Here, the configuration along one direction is not limited to the case of being arranged in a straight line. Overall, it is sufficient as long as they are arranged along an imaginary line to a degree that can compactly construct the magnetic detection device and the magnetic detection module including the magnetic detection device.

[0063] Furthermore, the magnetic detection systems 10 and 20 described in the first and second embodiments are particularly effective when incorporated into gear-driven or motor-driven detection devices. Gear- or motor-driven devices are often used in environments subject to the spread of dust or oil, but compared to contact-type and optical detection devices, even in such environments, measurement results are less likely to be affected. Furthermore, they are also suitable for incorporating encoders, which are often used in such environments.

Claims

1. A magnetic detection device, wherein: The device comprises a first detection unit, a magnet, and a second detection unit which are sequentially arranged along one direction. The first detecting portion detects a change in magnetic force from the magnet caused by a first convex row consisting of at least one convex portion provided on the moving body passing between the first detecting portion and the magnet as the moving body moves. The second detection portion detects a change in magnetic force from the magnet caused by a second convex row composed of at least one convex portion provided on the movable body passing between the magnet and the second detection portion as the movable body moves.

2. The magnetic detection device according to claim 1, wherein The first detection unit includes at least two magnetic sensors along the moving direction of the moving object.

3. The magnetic detection device according to claim 1, wherein The magnet has a yoke on either a first surface side facing the first detection portion or a second surface side facing the second detection portion.

4. The magnetic detection device according to claim 3, wherein: The yoke has an opening portion through which the magnetic force of the magnet passes.

5. The magnetic detection device according to claim 1, wherein The magnetization direction of the magnet is parallel to the one direction. The magnetic detection device according to claim 1 , wherein: The number of the protrusions constituting the second protrusion row is smaller than the number of the protrusions constituting the first protrusion row, The first detection unit outputs the change in magnetic force from the magnet as an analog signal. The second detection unit outputs a change in magnetic force from the magnet as a digital signal.

7. A magnetic detection module, wherein: have: The magnetic detection device according to any one of claims 1 to 6; and A base material portion is used to position the first detection portion, the magnet, and the second detection portion.

8. A magnetic detection system, wherein: have: The magnetic detection device according to any one of claims 1 to 6; and The mobile object.

9. The magnetic detection system according to claim 8, wherein: In the moving direction of the movable body, a ratio of the width of the convex portion to the interval between two adjacent convex portions constituting the first convex row is not less than 8% and not more than 40%.

10. The magnetic detection system according to claim 8, wherein: The moving body is a rotating body having a rotation center on a straight line along the one direction, The magnetic detection device detects a rotation angle of the rotating body.

11. The magnetic detection system according to claim 8, wherein: The moving body is a linear motion body that moves along a straight line perpendicular to the one direction. The magnetic detection device detects the position of the linear motion body.

12. A gear driven detection device, wherein: A magnetic detection system according to claim 8 is provided.

13. A motor driven detection device, wherein: A magnetic detection system according to claim 8 is provided.

14. An encoder, wherein A magnetic detection system according to claim 8 is provided.

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