Rotation Detection Device

Abstract

To provide a rotation detector with which, even when using a high sensitivity MR element as a magnetism detection element, it is possible to suppress decrease in detection accuracy and downsize a sensor unit.SOLUTION: A rotation detector 1 comprises: a member 2 to be detected, which is attached to a rotary member, and to which a plurality of magnetic poles is provided along a circumferential direction; and a sensor unit 3 that is attached to a stationary member and located facing the member 2 to be detected. The sensor unit 3 has a magnetic sensor 4 having a tabular detection unit 40 that includes a magnetism detection element ad a connecting terminal 41 that is extended from the detection unit 40, and a housing unit 5 that is provided so as to cover the magnetic sensor 4. The magnetism detection element is composed of a magnetoresistive effect element that detects a magnetic field in a direction perpendicular to a plate thickness direction of the detection unit 40, and the sensor unit 3 has its tip, which is an edge on a side opposite the extension side in the connecting terminal 41 of the detection unit 40 of the magnetic sensor 4, provided so as to face an end face in an axial direction of the member 2 to be detected.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a rotation detection device. [Background technology]

[0002] Conventionally, there is known a rotation detection device that is used, for example, in a bearing unit of a wheel to detect the rotation speed of a rotating member that rotates together with the wheel. In the rotation detection device, a magnetic sensor provided in a sensor unit detects a change in a magnetic field caused by a ring-shaped magnet (called a detected member) attached to the rotating member, thereby detecting the rotation speed of the rotating member.

[0003] In general, a magnetic sensor has a plate-shaped detection section including a magnetic detection element that detects a magnetic field from a member to be detected, and a connection terminal extending from the detection section. In a conventional rotation detection device, the sensor section is arranged so that one surface of the detection section faces the axial end face of the member to be detected (i.e., so that the detection section and the axial end face of the member to be detected face each other in the plate thickness direction of the detection section) (see, for example, Patent Document 1). In order to improve detection accuracy, the distance between the member to be detected and the detection section is generally set as short as possible. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-184094 A Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, magnetoresistance effect elements (MR elements) have been widely used as magnetic detection elements, and the sensitivity of MR elements has been greatly improved. When such a highly sensitive MR element is used as a magnetic detection element, if a sensor unit is disposed so that one surface of the detection unit faces an axial end surface of a detected member as in the past, the magnetic detection element may be too close to the detected member, causing excessive change in magnetic flux density at the magnetic detection position, resulting in saturation of the change in resistance value of the magnetic detection element and a decrease in detection accuracy.

[0006] To solve this problem, for example, it is possible to provide the detection unit at a position far from the detected member within the sensor unit, but in this case, there is a risk that the sensor unit will become large. In addition, it is also possible to move the sensor unit itself away from the detected member, but this may not be possible if the installation space for the sensor unit is narrow.

[0007] Therefore, an object of the present invention is to provide a rotation detection device that can suppress a decrease in detection accuracy even when a highly sensitive MR element is used as a magnetic detection element, and that allows the sensor unit to be reduced in size. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present invention provides a rotation detection device comprising: a detectable member attached to a rotating member and having a plurality of magnetic poles arranged circumferentially around the rotation axis of the rotating member; and a sensor unit attached to a fixed member that does not rotate with the rotation of the rotating member and arranged opposite the detectable member, wherein the sensor unit has a magnetic sensor having a plate-shaped detection unit including a magnetic detection element that detects a magnetic field from the detectable member and a connection terminal extending from the detection unit; and a housing unit arranged to cover the magnetic sensor, wherein the magnetic detection element is a magnetoresistive effect element that detects a magnetic field in a direction perpendicular to the plate thickness direction of the detection unit, and the sensor unit is arranged so that a tip portion, which is the end portion of the detection unit of the magnetic sensor opposite the extending side of the connection terminal, faces the axial end face of the detectable member. Effect of the Invention

[0009] According to the present invention, it is possible to provide a rotation detection device that can suppress a decrease in detection accuracy even when a highly sensitive MR element is used as a magnetic detection element, and that can reduce the size of the sensor unit. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a rotation detection device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a perspective view showing the appearance of a sensor unit. [Diagram 3] 5A and 5B are diagrams showing a schematic view of the internal structure of the sensor unit, in which FIG. 5A is a side view seen from the circumferential direction of the detection member, and FIG. 5B is a front view seen from the radial direction of the detection member. [Figure 4] 5A and 5B are diagrams for explaining the arrangement of a magnetic sensor relative to a detection member, where FIG. 5A is a plan view and FIG. [Diagram 5] FIG. 4 is a cross-sectional view of the tip of the sensor unit. [Figure 6] FIG. 13 is a side view showing an internal structure of a sensor unit according to a modified example of the present invention. [Figure 7] 13(a) and 13(b) are side views showing the internal structure of a sensor unit according to a modified example of the present invention. [Figure 8] FIG. 1A is a side view showing the internal structure of a sensor unit according to a modified example of the present invention, FIG. 1B is a plan view explaining the arrangement of a magnetic sensor relative to a member to be detected, and FIG. 1C is a front view of the member to be detected in FIG. [Figure 9] 8(b) is a graph showing an example of the distribution of magnetic flux density in the cross section taken along line AA in FIG. 8(b). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [Embodiment Mode] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0012] Fig. 1 is a schematic diagram of a rotation detection device according to the present embodiment. As shown in Fig. 1, the rotation detection device 1 includes a detection target member 2 and a sensor unit 3. The rotation detection device 1 is used, for example, to detect the rotation speed of the wheels of an automobile, i.e., the wheel speed.

[0013] (Detection target 2) The detected member 2 is attached to a rotating member (not shown) and rotates together with the rotating member. When the rotation detection device 1 is used to detect the wheel speed, the rotating member is, for example, an inner ring to which the wheel is attached and which rotates together with the wheel. The detected member 2 is formed in an annular shape and in a plate shape perpendicular to the rotation axis of the rotating member, and is attached to, for example, the outer circumferential surface of the rotating member.

[0014] In this embodiment, the detected member 2 is a magnetic encoder having multiple magnetic poles arranged along the circumferential direction centered on the rotation axis of the rotating member. The detected member 2 has N magnetic poles and S magnetic poles arranged alternately along the circumferential direction.

[0015] (Sensor part 3) Fig. 2 is a perspective view showing the external appearance of the sensor unit 3. Fig. 3 is a diagram showing a schematic internal structure of the sensor unit 3, in which (a) is a side view seen from the circumferential direction of the detection member 2, and (b) is a front view seen from the radial direction of the detection member 2.

[0016] 1 to 3, the sensor unit 3 has one magnetic sensor 4 and a housing unit 5 provided to collectively cover the magnetic sensor 4. The sensor unit 3 is provided at the end of a cable 6, and is attached to a fixed member that does not rotate with the rotation of a rotating member. When the rotation detection device 1 is used to detect wheel speed, the fixed member is, for example, a knuckle that is connected to the body of an automobile and supports an outer wheel.

[0017] The sensor unit 3 is disposed facing the detected member 2. The sensor unit 3 is provided such that its tip, which is the end opposite to the extension side of the cable 6, faces the axial end face of the detected member 2. More specifically, the sensor unit 3 is provided such that its tip faces the axial end face of the detected member 2 in the axial direction of the detected member 2. The extension direction of the cable 6 from the sensor unit 3 is parallel to the axial direction of the detected member 2.

[0018] The cable 6 has a pair of electric wires 61. Each electric wire 61 has a central conductor 61a made of a twisted conductor made of twisted wires having good electrical conductivity such as copper, and an insulator 61b made of insulating resin such as cross-linked polyethylene that covers the outer periphery of the central conductor 61a. The cable 6 further has a sheath 62 that collectively covers the pair (two) of electric wires 61.

[0019] At the end of the cable 6, a pair of electric wires 61 are exposed from the sheath 62, and further, at the end of each electric wire 61, a central conductor 61a is exposed from an insulator 61b. The tip of the central conductor 61a exposed from the insulator 61b is electrically connected to the corresponding connection terminal 41 of the magnetic sensor 4 by welding.

[0020] (Magnetic sensor 4) The magnetic sensor 4 has a plate-shaped detection portion 40 including a magnetic detection element (not shown) that detects a magnetic field from the detection target member 2, and a pair of connection terminals 41 extending from the detection portion 40.

[0021] The magnetic detection element is composed of an MR element (magnetoresistance effect element) that detects a magnetic field in a direction perpendicular to the plate thickness direction of the detection unit 40, i.e., in a direction parallel to the surface of the detection unit 40. In this embodiment, a GMR (Giant Magneto Resistive effect) element is used as the magnetic detection element. Note that an AMR (Anisotropic Magneto Resistive) element or a TMR (Tunneling Magneto Resistive) element can also be used as the magnetic detection element.

[0022] The detection unit 40 has a magnetic detection element, a signal processing circuit (not shown), and a resin mold 40a as a cover for collectively covering the magnetic detection element and the signal processing circuit. The detection unit 40 is formed in a plate shape that is substantially rectangular (having one of the four corners of the rectangle chamfered) in a plan view.

[0023] The pair of connection terminals 41 extend from one long side (the long side not connected to the chamfered corner) of the detection unit 40 in a direction perpendicular to the long side, and both connection terminals 41 are formed parallel to each other. Both connection terminals 41 are provided linearly without bending. Both connection terminals 41 are formed in a strip shape (long, thin plate shape), and the central conductor 61a of the corresponding electric wire 61 is electrically connected to its tip end (the end opposite to the detection unit 40).

[0024] A capacitance element for suppressing noise is connected between both connection terminals 41, and a capacitance element protection part 42 formed by resin molding is provided so as to cover the capacitance element and the surrounding connection terminals 41. Hereinafter, the extension direction of the connection terminals 41 will be referred to as the length direction of the detection part 40, and the direction perpendicular to the length direction and the plate thickness direction will be referred to as the width direction of the detection part 40. In addition, the end part of the detection part 40 opposite to the extension side of the connection terminals 41 (the end part on the long side connected to the chamfered corner part) will be referred to as the tip part.

[0025] The magnetic sensor 4 is provided such that the tip of the detection section 40 faces the tip side of the sensor section 3. The detection section 40 of the magnetic sensor 4 has a plurality of (2 to 5) magnetic detection elements arranged in a line in the width direction. In Fig. 3, the position where the magnetic field is detected by the magnetic detection elements is indicated by the symbol 40b.

[0026] In the rotation detection device 1 according to this embodiment, the sensor unit 3 is provided so that the tip portion of the detection unit 40 of the magnetic sensor 4 (the tip portion of the sensor unit 3) faces the axial end face of the detection target member 2. More specifically, the sensor unit 3 is provided so that the length direction of the detection unit 40 coincides with the axial direction of the detection target member 2 (so that the length direction of the detection unit 40 is perpendicular to the axial end face of the detection target member 2).

[0027] By configuring in this way, it is possible to separate the magnetic field detection position 40b from the detected member 2 while keeping the distance (air gap) between the sensor unit 3 and the detected member 2 at the same level as in the conventional technology in which one surface of the detection unit 40 faces the axial end surface of the detected member 2. By separating the magnetic field detection position 40b from the detected member 2, it is possible to suppress the change in magnetic flux density at the magnetic field detection position 40b to be relatively small. As a result, even when a highly sensitive MR element such as a GMR element is used as the magnetic detection element, it is possible to suppress the deterioration of detection accuracy due to saturation of resistance value change. In addition, for example, in the magnetic sensor 4 configured to be able to detect the rotation direction, it may take time to enable the detection of the rotation direction when the resistance value change of the magnetic detection element is saturated. However, according to the present embodiment, it is possible to quickly enable the detection of the rotation direction because the change in magnetic flux density at the magnetic field detection position 40b can be suppressed to be relatively small.

[0028] Furthermore, according to this embodiment, the distance (air gap) between the sensor unit 3 and the detected member 2 can be maintained at the same level as in the conventional embodiment, making it easy to arrange the sensor unit 3 even when the arrangement space is narrow. Furthermore, in this embodiment, there is no need to bend the connection terminal 41, making it easy to manufacture and avoiding the risk of damage to the detection unit 40 due to bending. Also, since there is no need to bend the connection terminal 41, the entire sensor unit 3 can be made smaller.

[0029] Incidentally, the detection unit 40 is configured to calculate the difference between the detection values ​​of the magnetic flux densities detected at both detection positions 40b, and output a signal according to the calculated difference via the connection terminal 41. Therefore, for example, if the magnetic sensor 4 is arranged so that the radial direction of the detected member 2 and the width direction of the detection unit 40 coincide with each other, the changes in the magnetic field at both detection positions 40b will be almost the same, and the output of the difference will be almost zero, which may result in a decrease in detection accuracy.

[0030] 4(a) and (b), in this embodiment, the sensor unit 3 is provided so that the plate thickness direction of the detection unit 40 coincides with the radial direction of the detected member 2. This generates a phase difference between the magnetic fields detected at both detection positions 40b, making it possible to increase the differential output and improve the detection accuracy.

[0031] (Housing part 5) 5, the housing part 5 has a holder 51 that holds the magnetic sensor 4, and a resin molded part 52 that covers the periphery of the holder 51. The holder 51 is a member for protecting the magnetic sensor 4 and the connection part between the magnetic sensor 4 and the cable 6 when molding the resin molded part 52, and is formed in advance by injection molding or the like. The housing part 5 is formed by molding resin with the two magnetic sensors 4 and the cable 6 set in the holder 51 to form the resin molded part 52.

[0032] In this embodiment, the housing part 5 facing the tip of the detection part 40 is composed of only the holder 51. That is, in this embodiment, the housing part 5 facing the tip of the detection part 40 is not covered with the resin mold part 52, and the holder 51 is exposed in the part facing the detected member 2 and faces directly. This allows the housing part 5 at the tip of the sensor part 3 to be composed of only the thickness of one member (holder 51), and the housing part 5 at the tip of the sensor part 3 can be made very thin. As a result, it is possible to suppress a decrease in detection accuracy caused by the magnetic field detection position 40b being too far away from the detected member 2.

[0033] 2, the resin molded part 52 is formed by integrally forming a main body part 520 which collectively covers the magnetic sensor 4, the end of the cable 6, and the holder 51, and a flange part 521 for fixing the sensor part 3 to a fixed member. A bolt hole 522 for passing a bolt (not shown) for fixing the sensor part 3 to the fixed member is formed in the flange part 521, and a collar 523 made of metal is provided in the bolt hole 522 so as to fit along the inner peripheral surface of the bolt hole 522 in order to suppress deformation of the flange part 521 when the bolt is fixed.

[0034] (Modification) In the above embodiment, the magnetic sensor 4 is positioned so that the detection portion 40 is perpendicular to the axial end face of the detected member 2, but it is not necessary for the detection portion 40 to be strictly perpendicular to the axial end face of the detected member 2, and some inclination is permissible.

[0035] 6, the inclination θ of the length direction of the detection unit 40 with respect to the axial direction of the detection member 2 is preferably 30 degrees or less. If the inclination θ is greater than 30 degrees, the sensor unit 3 may become large.

[0036] In the above embodiment, the case has been described where the extending direction of the cable 6 in the sensor unit 3 coincides with the length direction of the detection unit 40, but the extending direction of the cable 6 does not have to coincide with the length direction of the detection unit 40. For example, as shown in Fig. 7(a), the cable 6 may be bent within the housing unit 5, or as shown in Fig. 7(b), the connection terminal 41 may be bent within the housing unit 5. In Figs. 7(a) and (b), the cable 6 and the connection terminal 41 are bent by 90 degrees, but the bending angle can be changed as appropriate.

[0037] This makes it possible to appropriately change the angle of the tip of sensor unit 3 relative to the extending direction of cable 6 (the direction in which the tip of detection unit 40 faces), and to flexibly adjust the shape of sensor unit 3 according to the shape of the fixing member on which sensor unit 3 is mounted. However, from the viewpoints of ease of manufacture and miniaturization, it is more preferable that the extending direction of cable 6 in sensor unit 3 coincides with the length direction of detection unit 40.

[0038] Furthermore, as shown in Figures 8(a) to (c), the sensor unit 3 may be provided with two magnetic sensors 4 for redundancy. To reduce the size of the sensor unit 3, it is desirable to arrange the two magnetic sensors 4 in an aligned manner so that the detection sections 40 are aligned in the plate thickness direction. In this case, the two magnetic sensors 4 are arranged side by side in the radial direction of the detected member 2 (see Figure 8(b)).

[0039] When two magnetic sensors 4 are provided, the sensor unit 3 is provided so that the tip portions of the detection portions 40 of both magnetic sensors 4 (tip portions of the sensor unit 3) face the axial end faces of the detection target member 2. This allows the distance between the detection portions 40 of the two magnetic sensors 4 and the detection target member 2 (the distance between the magnetic field detection position 40b and the detection target member 2) to be approximately the same, and allows both detection portions 40 to be arranged close to each other. Considering the functional safety defined in ISO26262, it is desirable to make the outputs of both magnetic sensors 4 as equal (homogeneous) as possible, that is, to homogenize the outputs of the two magnetic sensors 4. However, by arranging the sensor unit 3 so that the tip portions of the detection portions 40 of both magnetic sensors 4 face the axial end faces of the detection target member 2, it is possible to make the outputs of the two magnetic sensors 4 approximately the same and homogenize them.

[0040] FIG. 9 shows an example of the distribution of magnetic flux density in the cross section of line AA in FIG. 8(b). As shown in FIG. 9, in this example, the distribution of magnetic flux density is symmetrical in the radial cross section of the detection member 2 such that the magnetic flux density is highest at the radial center position of the detection member 2 and decreases as it moves away from the radial center position. Therefore, in this case, by adjusting the position of the sensor unit 3 so that the detection positions 40b of both magnetic sensors 4 are symmetrical with respect to the radial center position of the detection member 2, it becomes possible to obtain almost the same output from both magnetic sensors 4, and to achieve a very high level of homogenization. Note that the distribution of magnetic flux density in FIG. 9 is only an example. For example, if the magnetic flux density is maximum at a position shifted from the radial center position of the detection member 2, it is advisable to adjust the position of the sensor unit 3 so that the detection positions 40b of both magnetic sensors 4 are symmetrical with respect to the position where the magnetic flux density is maximum.

[0041] When using two magnetic sensors 4, it is desirable to match the front and back of the two magnetic sensors 4. For example, if the front and back of the two magnetic sensors 4 are inverted, the rotation directions detected by the two magnetic sensors 4 will be opposite, and a downstream computing device will need to perform a computation taking this into account, reducing versatility. By matching the front and back of the two magnetic sensors 4, the rotation directions detected by the two magnetic sensors 4 can be aligned to the same direction, improving versatility.

[0042] (Functions and Effects of the Embodiments) As described above, in the rotation detection device 1 of this embodiment, the magnetic detection element is composed of an MR element that detects a magnetic field in a direction perpendicular to the thickness direction of the detection section 40, and the sensor section 3 is arranged so that the tip end of the detection section 40 of the magnetic sensor 4 faces the axial end face of the detected member 2.

[0043] This makes it possible to separate the magnetic field detection position 40b from the detected member 2 while keeping the distance between the sensor unit 3 and the detected member 2 at the same level as in the past, and to suppress the change in magnetic flux density at the magnetic field detection position 40b to a relatively small value. As a result, even when a highly sensitive MR element is used as the magnetic detection element and the sensor unit 3 and the detected member 2 need to be placed close to each other due to a narrow installation space, it is possible to suppress the deterioration of detection accuracy due to saturation of the resistance value change. Furthermore, since there is no need to bend the connection terminal 41, the manufacturing is simplified, the risk of damage to the detection unit 40 due to bending can be avoided, and the size of the sensor unit 3 due to bending the connection terminal 41 can be suppressed, thereby realizing a rotation detection device 1 having a small sensor unit 3.

[0044] Furthermore, according to this embodiment, in a conventional sensor unit, the sensor unit 3 can be realized simply by replacing the magnetic sensor using a Hall element with the magnetic sensor 4 using an MR element, making it highly versatile.

[0045] (Summary of the embodiment) Next, the technical ideas grasped from the above-described embodiment will be described by using the reference numerals and the like in the embodiment. However, the reference numerals and the like in the following description do not limit the components in the claims to the members and the like specifically shown in the embodiment.

[0046] [1] A rotation detection device (1) comprising: a detectable member (2) attached to a rotating member and having a plurality of magnetic poles arranged in a circumferential direction centered on the rotation axis of the rotating member; and a sensor unit (3) attached to a fixed member that does not rotate with the rotation of the rotating member and arranged opposite the detectable member, wherein the sensor unit (3) has a magnetic sensor (4) having a plate-shaped detection unit (40) including a magnetic detection element that detects a magnetic field from the detectable member (2) and a connection terminal (41) extending from the detection unit (40); and a housing unit (5) provided to cover the magnetic sensor (4), wherein the magnetic detection element is a magnetoresistance effect element that detects a magnetic field in a direction perpendicular to the plate thickness direction of the detection unit (40), and the sensor unit (3) is provided so that a tip portion, which is an end portion of the detection unit (40) of the magnetic sensor (4) opposite to the extending side of the connection terminal (41) faces an axial end face of the detectable member (2).

[0047] [2] The rotation detector (1) according to [1], wherein the connection terminal (41) is provided linearly without having any bent portion.

[0048] [3] The rotation detection device (1) described in [1] or [2], wherein the detection unit (40) has a plurality of the magnetic detection elements arranged in a line in a length direction which is the extension direction of the connection terminal (41) and a width direction perpendicular to the plate thickness direction, and the sensor unit (3) is arranged so that the plate thickness direction of the detection unit (40) coincides with the radial direction of the detected member (2).

[0049] [4] The rotation detection device (1) described in any one of [1] to [3], wherein the housing portion (5) has a holder (51) that holds the magnetic sensor (4) and a resin molded portion (52) that covers the periphery of the holder (51), and the portion of the housing portion (5) that faces the tip end of the detection portion (40) is composed only of the holder (51).

[0050] [5] The rotation detection device (1) described in any one of [1] to [4], wherein the sensor unit (3) has two of the magnetic sensors (4), and the two magnetic sensors (4) are arranged so that the detection unit (40) is aligned in the plate thickness direction of the detection unit (40).

[0051] Although the embodiment of the present invention has been described above, the invention according to the claims is not limited to the embodiment described above. It should be noted that not all of the combinations of features described in the embodiment are essential to the means for solving the problems of the invention. The present invention can be modified appropriately without departing from the spirit of the invention. [Explanation of symbols]

[0052] 1...Rotation detection device 2...Detection target 3. Sensor section 4. Magnetic sensor 40…Detection section 40a…Resin mold 40b…Magnetic field detection position 41...Connection terminal 42...Capacitor element protection section 5…Housing section 51...Holder 52…Resin molded part 6…Cable

Claims

1. a ring-shaped detection member attached to a rotating member and having a plurality of magnetic poles provided along a circumferential direction centered on a rotation axis of the rotating member; a sensor unit attached to a fixed member that does not rotate with the rotation of the rotating member and disposed opposite the detection member; The sensor unit includes: two magnetic sensors each having a plate-shaped detection portion including a magnetic detection element for detecting a magnetic field from the detection target member; a housing portion provided to cover the magnetic sensor, the magnetic detection element is a magnetoresistance effect element that detects a magnetic field in a direction perpendicular to a plate thickness direction of the detection portion, the sensor portion is provided such that an end portion of the housing portion on which the detection portion is disposed faces an axial end surface of the detection member, a thickness of an end portion of the housing portion facing the axial end face is smaller than a radial width of the detection member; The two magnetic sensors are arranged so that the detection portions are aligned in a plate thickness direction of the detection portions, and the plate thickness direction of the detection portions coincides with the radial direction of the detected member, and the detection positions of the two magnetic sensors are arranged at positions symmetrical to a position where the magnetic flux density is maximum in the radial direction of the detected member. Rotation detection device.

2. The longitudinal direction of the housing portion intersects with the radial direction of the detection member. The rotation detection device according to claim 1 .

3. the housing portion includes a holder that holds the magnetic sensor, and a resin molded portion that covers a periphery of the holder, the housing portion facing the tip end of the detection portion is constituted only by the holder, and the resin molded portion is not interposed between the detection portion and the detected member; 3. The rotation detection device according to claim 1 or 2.

4. The position at which the magnetic flux density is maximum in the radial direction of the detection member is the radial center position of the detection member. The rotation detection device according to any one of claims 1 to 3.

5. a cable connected to the magnetic sensor and a portion of the cable in a longitudinal direction thereof is covered by the housing portion; The cable extends from an end portion of the housing portion opposite to an end portion on which the detection portion is disposed. The rotation detection device according to any one of claims 1 to 4.

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