阅读说明：本技术 旋转检测装置及带传感器电缆 (Rotation detection device and cable with sensor ) 是由 鬼本隆 城田照昌 于 2017-06-22 设计创作，主要内容包括：本发明提供旋转检测装置及带传感器电缆。所述旋转检测装置是通过磁性传感器来检测旋转构件的旋转速度的旋转检测装置,具备安装于旋转构件的被检测构件、以及安装于不会随着旋转构件的旋转而旋转的固定构件的传感器部,在固定构件形成有在与旋转构件的旋转轴交叉的方向上贯通的贯通孔,传感器部具备多个磁性传感器和被覆多个磁性传感器的外壳部,磁性传感器具有检测部,检测部具有磁性检测元件和覆盖磁性检测元件的被覆体,外壳部沿着与旋转轴交叉的方向插入所述贯通孔中,各个检测部在偏离于旋转轴的位置并在与外壳部插入所述贯通孔中的插入方向交叉的方向上,与被检测构件并排地配置。(The invention provides a rotation detecting device and a cable with a sensor. The rotation detecting device is a rotation detecting device for detecting a rotation speed of a rotating member by a magnetic sensor, and includes a detected member attached to the rotating member and a sensor unit attached to a fixed member that does not rotate with rotation of the rotating member, the fixed member being formed with a through hole that penetrates in a direction intersecting a rotation axis of the rotating member, the sensor unit including a plurality of magnetic sensors and a housing unit that covers the plurality of magnetic sensors, the magnetic sensor including a detecting unit that includes a magnetic detecting element and a covering body that covers the magnetic detecting element, the housing unit being inserted into the through hole in a direction intersecting the rotation axis, and each detecting unit being disposed in parallel with the detected member at a position offset from the rotation axis and in a direction intersecting an insertion direction in which the housing unit is inserted into the through hole.)

1. A rotation detection device for detecting the rotation speed of a rotating member by a magnetic sensor, comprising:

a detected member attached to the rotating member; and

a sensor unit attached to a fixed member that does not rotate with the rotation of the rotating member,

a through hole penetrating in a direction intersecting with a rotation axis of the rotating member is formed in the fixed member,

the sensor unit includes a plurality of the magnetic sensors and a housing unit covering the plurality of the magnetic sensors,

the magnetic sensor has a detection unit having a magnetic detection element and an adherend covering the magnetic detection element,

the housing portion is inserted into the through hole in a direction intersecting the rotation axis,

each of the detection units is disposed in parallel with the member to be detected at a position offset from the rotation axis and in a direction intersecting an insertion direction of the housing unit into the through hole.

2. The rotation detecting device according to claim 1, the housing portion having a flange portion for fixing the sensor portion to the fixing member,

the flange portion extends in a direction in which the respective detection portions are aligned with the detected member.

3. The rotation detecting device according to claim 1 or 2,

the outer shell portion comprises any one of polyamide, nylon, polybutylene terephthalate.

4. The rotation detecting device according to any one of claims 1 to 3,

the magnetic sensor disposed farthest from the detection target member has higher sensitivity than the magnetic sensor disposed closest to the detection target member.

5. A sensor-equipped cable for a rotation detection device for detecting the rotation speed of a rotating member by a magnetic sensor, the rotation detection device comprising:

a detected member attached to the rotating member; and

a sensor unit attached to a fixed member that does not rotate with the rotation of the rotating member,

the sensor-equipped cable has:

a cable; and

the sensor portion provided at an end portion of the cable,

a through hole penetrating in a direction intersecting with a rotation axis of the rotating member is formed in the fixed member,

the sensor unit includes a plurality of the magnetic sensors and a housing unit covering the plurality of the magnetic sensors,

the magnetic sensor has a detection unit having a magnetic detection element and an adherend covering the magnetic detection element,

the housing portion is inserted into the through hole in a direction intersecting the rotation axis,

each of the detection units is disposed in parallel with the member to be detected at a position offset from the rotation axis and in a direction intersecting an insertion direction of the housing unit into the through hole.

6. The sensor-equipped cable according to claim 5, a plurality of the magnetic sensors each having a connection terminal protruding from the detection portion,

the cable has a plurality of wires connected to the connection terminals of the respective plurality of magnetic sensors,

the sensor-equipped cable includes a single connector provided at an end of the plurality of electric wires and shared by the plurality of electric wires.

Technical Field

The present invention relates to a rotation detecting device and a cable with a sensor.

Background

A rotation detecting device for detecting a rotation speed of a rotating member rotating together with a wheel, which is used in a bearing unit of the wheel, is known (for example, see patent document 1).

Patent document 1 describes a rotation detection device including: the magnetic sensor includes a detected member attached to a rotating member and having a plurality of magnetic poles in a circumferential direction of the rotating member, and a magnetic sensor attached to a fixed member rotatably supporting the rotating member and having a detection element detecting a magnetic field of the detected member.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-47636

Disclosure of Invention

Problems to be solved by the invention

In a rotation detecting device for measuring the rotation speed of a wheel, there is a demand for using a plurality of magnetic sensors so that the rotation speed of the wheel can be detected even if a failure or the like of the magnetic sensors occurs, or the rotation speed of the wheel can be detected with higher accuracy.

When a plurality of magnetic sensors are mounted on the sensor portion, the size of the entire sensor portion may increase, and a problem may occur in that the magnetic sensors cannot be inserted into a holding hole for holding the sensor portion, for example. Therefore, there is a demand for keeping the size of the sensor unit small even when a plurality of magnetic sensors are mounted.

The invention aims to provide a rotation detecting device and a sensor-equipped cable, which can make a sensor part small even if a plurality of magnetic sensors are provided.

Means for solving the problems

In order to solve the above problem, a rotation detecting device according to one aspect of the present invention includes: a detection member attached to a rotating member and having a plurality of magnetic poles arranged along a circumferential direction around a rotation axis of the rotating member; and a sensor unit that is attached to a fixed member that does not rotate with rotation of the rotating member and is disposed to face the detected member, wherein the sensor unit includes a plurality of magnetic sensors, the magnetic sensors include a plate-shaped detection unit, and the detection unit includes: the magnetic sensor includes a magnetic detection element that detects a magnetic field from the detection target member, a signal processing circuit that processes a signal output from the magnetic detection element, and a cover that covers the magnetic detection element and the signal processing circuit together, wherein the detection units are stacked in a direction in which the sensor units face the detection target member, and the magnetic sensor disposed farthest from the detection target member has higher sensitivity than the magnetic sensor disposed closest to the detection target member.

In order to solve the above-described problems, a cable with a sensor according to an aspect of the present invention is a cable with a sensor for use in a rotation detecting device, the rotation detecting device including: a detection member attached to a rotating member and having a plurality of magnetic poles arranged along a circumferential direction around a rotation axis of the rotating member; and a sensor unit attached to a fixed member that does not rotate with rotation of the rotating member and disposed opposite the detected member, the sensor-equipped cable including: a cable and the sensor unit provided at an end of the cable, wherein the sensor unit includes a plurality of magnetic sensors, the magnetic sensors include a plate-shaped detection unit, and the detection unit includes: the magnetic sensor includes a magnetic detection element that detects a magnetic field from the detection target member, a signal processing circuit that processes a signal output from the magnetic detection element, and a cover that covers the magnetic detection element and the signal processing circuit together, and the detection units are stacked in a direction in which the sensor unit and the detection target member face each other.

ADVANTAGEOUS EFFECTS OF INVENTION

According to one embodiment of the present invention, a rotation detecting device and a sensor-equipped cable are provided in which a sensor unit can be made small even if a plurality of magnetic sensors are provided.

Drawings

Fig. 1 is a cross-sectional view showing a rotation detecting device according to an embodiment of the present invention and a wheel bearing device for a vehicle provided with the rotation detecting device.

Fig. 2 is a perspective view showing a sensor unit.

Fig. 3A is a side view showing the sensor portion.

Fig. 3B is a sectional view showing the housing in section in fig. 3A, fig. 3B.

Fig. 4A is a plan view showing the sensor portion.

Fig. 4B is a sectional view showing the housing in section in fig. 4A, fig. 4B.

Fig. 4C is a plan view showing the magnetic sensor and the electric wire.

Fig. 5A and 5A are explanatory views showing a sensor-equipped cable according to a modification of the present invention.

Fig. 5B is a sectional view showing the cable of fig. 5A.

Description of the symbols

1 … rotation detecting device, 2 … magnetic encoder (detected member), 3 … sensor unit, 30 … magnetic sensor, 300 … detecting unit, 300a … resin molding (covering body), 301 … connecting terminal, 31 … outer housing unit, 4 … cable, 9 … knuckle (fixed member), 10 … wheel bearing device, 11 … inner wheel (rotating member), 12 … outer wheel, 13 … rotating body, 100 … sensor-equipped cable.

Detailed Description

[ embodiment ]

Hereinafter, embodiments of the present invention will be described based on the drawings.

(constitution of wheel bearing device 10)

Fig. 1 is a cross-sectional view showing a rotation detecting device according to the present embodiment and a wheel bearing device for a vehicle provided with the rotation detecting device.

The wheel bearing device 10 includes: an inner ring 11 as a rotating member having a cylindrical body portion 110 and a flange portion 111 for mounting a wheel; an outer ring 12 disposed on the outer peripheral side of the body 110 of the inner ring 11; a plurality of spherical rolling elements 13 disposed between a pair of raceway surfaces 11b and 11b formed on an outer peripheral surface 11a of the inner ring 11 and a pair of raceway surfaces 12b and 12b formed on an inner peripheral surface 12a of the outer ring 12 and rolling on the two pairs of raceway surfaces 11b and 12 b; and a rotation detecting device 1 that detects the rotation speed of the inner wheel 11 relative to the outer wheel 12 (i.e., the wheel rotation speed).

A through hole is formed along the rotation axis O in the central portion of the main body portion 110 of the inner ring 11, and a spline fitting portion 110a for connecting a drive shaft, not shown, is formed on the inner surface of the through hole. The pair of raceway surfaces 11b and 11b of the inner race 11 are formed parallel to each other so as to extend in the circumferential direction.

The flange portion 111 of the inner race 11 protrudes radially outward of the body portion 110 and is provided integrally with the body portion 110. The flange portion 111 is formed with a plurality of through holes 111a, and bolts for attaching a wheel, not shown, are press-fitted into the through holes 111 a.

The outer ring 12 is formed in a cylindrical shape and is fixed to a knuckle 9 connected to a vehicle body by a plurality of bolts 91 (only 1 is shown in fig. 1). The knuckle 9 is an example of a fixed member that rotatably supports the inner wheel 11. The pair of raceway surfaces 12b and 12b of the outer ring 12 are formed parallel to each other so as to extend in the circumferential direction while facing the pair of raceway surfaces 11b and 11b of the inner ring 11. A seal 14 is disposed between the flange portion 111 side end of the inner ring 11 of the outer ring 12 and the inner ring 11.

The knuckle 9 is formed with a holding hole 90 for holding the sensor unit 3 of the rotation detecting device 1 described below. The holding hole 90 has a circular cross section perpendicular to the central axis, and the holding hole 90 penetrates the knuckle 9 in the radial direction of the rotation axis O.

(description of the rotation detecting device 1)

Fig. 2 is a perspective view of the sensor unit. Fig. 3A is a side view showing the sensor unit, and fig. 3B is a sectional view showing the housing thereof in section. Fig. 4A is a plan view showing the sensor unit, fig. 4B is a sectional view showing the housing thereof in section, and fig. 4C is a plan view showing the magnetic sensor and the electric wire.

As shown in fig. 1 to 4, the rotation detecting device 1 includes: the magnetic encoder 2 as a member to be detected is attached to an inner ring 11 as a rotating member, and a plurality of magnetic poles (not shown) are provided along a circumferential direction around a rotation axis (rotation axis O) of the inner ring 11, and the sensor unit 3 is attached to a knuckle 9 as a fixed member that does not rotate with rotation of the inner ring 11, and is disposed to face the magnetic encoder 2.

The magnetic encoder 2 is formed in a ring shape having a thickness in a direction parallel to the rotation axis O. The magnetic encoder 2 is supported by a support member 112 fixed to the outer peripheral surface 11a of the inner ring 11, and is attached to rotate integrally with the inner ring 11. The magnetic encoder 2 has N magnetic poles and S magnetic poles that face the sensor unit 3 and are alternately arranged in the circumferential direction.

The sensor unit 3 is provided at an end of the cable 4. A product in which the sensor portion 3 is provided at the end of the cable 4 is the sensor-equipped cable 100 according to the present embodiment. In the present embodiment, the magnetic encoder 2 and the distal end portion of the sensor unit 3 face each other in the axial direction parallel to the rotation axis O.

In the rotation detecting device 1 according to the present embodiment, the sensor unit 3 includes: a plurality of magnetic sensors 30, and a housing 31 made of a resin molding material collectively covering the plurality of magnetic sensors 30. Here, a case where the sensor unit 3 includes 2 magnetic sensors 30 will be described.

The cable 4 has a plurality of pairs (here, 2 pairs) of electric wires 41 corresponding to the plurality of magnetic sensors 30. Each of the wires 41 has: a central conductor 41a formed of a twisted conductor obtained by twisting bare wires having good conductivity such as copper, and an insulator 41b formed of an insulating resin such as crosslinked polyethylene and covering the outer periphery of the central conductor 41 a. The cable 4 further includes a sheath 42 collectively covering 2 pairs (4) of the electric wires 41.

At the end of the cable 4, 2 pairs of wires 41 are exposed from the sheath 42, and further, at the end of the wire 41, the central conductor 41a is exposed from the insulator 41 b. The central conductor 41a exposed from the insulator 41b is electrically connected to the corresponding connection terminal 301 of the magnetic sensor 30 by resistance welding.

The magnetic sensor 30 includes a detection unit 300 and a pair of connection terminals 301 extending from the detection unit 300.

The detection unit 300 includes: a magnetic detection element (not shown) for detecting a magnetic field from the magnetic encoder 2, a signal processing circuit (not shown) for processing a signal output from the magnetic detection element, and a resin mold 300a as a coated body in which the magnetic detection element and the signal processing circuit are collectively coated. The detection unit 300 is formed in a plate shape having a substantially rectangular shape (a shape in which 1 of 4 corners of the rectangular shape is chamfered) in a plan view. The detection axis (the detection direction of the magnetic field) of the magnetic detection element is the vertical direction in fig. 4A (the tangential direction of a circle having the rotation axis O as the center).

The pair of connection terminals 301 extend from one long side (long side on the side not connected to the chamfered corner) of the detection portion 300 in a direction perpendicular to the long side, and the two connection terminals 301 are formed parallel to each other. In the present embodiment, the two connection terminals 301 are formed in a band shape, and the tip end portions (end portions on the opposite side from the detection portion 300) thereof are electrically connected to the central conductors 41a of the corresponding wires 41.

Further, the pair of connection terminals 301 of one magnetic sensor 30 (the magnetic sensor 30 on the lower side if referred to as fig. 3B) closer to the magnetic encoder 2 extend linearly in parallel in the same direction as the extending direction of the central conductor 41 a. On the other hand, the pair of connection terminals 301 of the other magnetic sensor 30 (the upper magnetic sensor 30 in fig. 3B) located farther from the magnetic encoder 2 is bent in a crank shape. In detail, the pair of connection terminals 301 of the other magnetic sensor 30 has a portion extending in parallel to the extending direction of the central conductor 41a from the connection portion with the central conductor 41a, a portion bent from the portion and extending in the direction of the one magnetic sensor 30 (in fig. 3B, the obliquely downward left direction), and a portion bent from the portion and extending in parallel to the extending direction of the central conductor 41 a.

Although not shown, a capacitor element for suppressing noise is connected between the two connection terminals 301, and a capacitor element protection portion 302 formed of a resin mold is provided so as to cover the capacitor element and the connection terminal 301 at a portion connected to the capacitor element. The capacitive element protection portion 302 provided in the other magnetic sensor 30 is disposed between the pair of connection terminals 301 of the one magnetic sensor 30 and the pair of connection terminals 301 of the other magnetic sensor 30 so as to effectively utilize a gap formed between the pair of connection terminals 301 in a straight shape and the pair of connection terminals 301 in a crank shape.

In the rotation detecting device 1 according to the present embodiment, the detecting portions 300 of the plurality of (2 in this case) magnetic sensors 30 are stacked in the facing direction of the sensor portion 3 and the magnetic encoder 2. Each of the detection units 30 is stacked in a direction intersecting with a lead-out direction in which the cable 4 is led out from the housing unit 31 (in the present embodiment, in a direction orthogonal thereto). In the present embodiment, the magnetic sensor 30 disposed farthest from the magnetic encoder 2 has higher sensitivity than the magnetic sensor 30 disposed closest to the magnetic encoder 2. When the cable 4 is bent and the bent portion connected to the cable 4 is collectively resin-molded to form the L-shaped case portion 31, the respective detection portions 30 are laminated in the same direction as the lead-out direction in which the cable 4 is led out from the case portion 31.

The detection portions 300 of the two magnetic sensors 30 are stacked in the thickness direction thereof. That is, in the present embodiment, the facing direction of the sensor unit 3 and the magnetic encoder 2 coincides with the thickness direction (stacking direction) of the detection unit 300. The facing direction of the sensor unit 3 and the magnetic encoder 2 and the thickness direction (stacking direction) of the detection unit 300 do not need to be exactly the same, and may be offset to some extent. That is, "the detection units 300 are stacked in the facing direction of the sensor unit 3 and the magnetic encoder 2" includes a case where the facing direction of the sensor unit 3 and the magnetic encoder 2 and the stacking direction of the detection units 300 are deviated by several degrees (for example, about ± 10 °).

In the present embodiment, the magnetic encoder 2 and the distal end portion of the sensor unit 3 face each other in the axial direction parallel to the rotation axis O, and therefore the thickness direction (stacking direction) of the detection unit 300 coincides with the axial direction. Further, not limited to this, for example, when the magnetic encoder 2 and the distal end portion of the sensor unit 3 are opposed to each other in the radial direction perpendicular to the rotation axis O, it is preferable that the thickness direction (stacking direction) of the detection unit 300 is aligned with the radial direction.

In the present embodiment, two detection units 300 are stacked directly. That is, the surface of one detection part 300 is in contact with the surface of the other detection part 300. This makes it possible to achieve a reduction in size, and also makes it easy to maintain a constant distance between the magnetic detection elements in the two detection units 300, as compared with the case where the two detection units 300 are disposed separately, and also makes it possible to minimize the distance between the magnetic sensor 30 disposed farther from the magnetic encoder 2 and the magnetic encoder 2, thereby improving detection accuracy. In the present embodiment, the two detection units 300 are not fixed by adhesion with an adhesive or the like, but the two detection units 300 are stacked and held on the housing 31 in a stacked state.

In addition, the two detection units 300 are preferably stacked such that at least a part of the two magnetic detection elements overlap each other in the facing direction (axial direction) of the sensor unit 3 and the magnetic encoder 2.

By using a plurality of magnetic sensors 30, even if one magnetic sensor 30 fails, detection can be continued using another magnetic sensor 30, and the reliability of the rotation detection device 1 is improved.

Further, by stacking the detection units 300 (stacking them in the thickness direction), for example, as compared with the case where the sensor units 3 are arranged in parallel in the width direction perpendicular to the thickness direction, the plurality of magnetic sensors 30 can be arranged compactly, and even when the plurality of magnetic sensors 30 are used, the entire sensor unit 3 can be kept small.

The thickness of the detection unit 300 is, for example, about 1mm, but when the detection units 300 of the two magnetic sensors 30 are disposed apart from each other for some reason or when the distance (interval) between the sensor unit 3 and the magnetic encoder 2 is relatively large, the intensity of the magnetic field detected by the magnetic sensor 30 disposed at a position relatively distant from the magnetic encoder 2 may be reduced, and the detection accuracy may be lowered.

Therefore, in the present embodiment, the sensitivity of the magnetic sensor 30 disposed farthest from the magnetic encoder 2 is set to be higher than the sensitivity of the magnetic sensor 30 disposed closest to the magnetic encoder 2. When 2 magnetic sensors 30 are used as in the present embodiment, a magnetic sensor having a higher sensitivity than the magnetic sensor 30 disposed on the magnetic encoder 2 side is used as the magnetic sensor 30 disposed on the side opposite to the magnetic encoder 2.

Here, "high sensitivity" means that a smaller magnetic field intensity can be detected. That is, the term "high sensitivity" means that the minimum value of the intensity of the detectable magnetic field is smaller.

In the present embodiment, a hall IC is used as the magnetic sensor 30 disposed on the magnetic encoder 2 side, and a GMR (Giant Magneto Resistive effect) sensor having higher sensitivity than the hall IC is used as the magnetic sensor 30 disposed on the side opposite to the magnetic encoder 2. In addition, when a hall IC is used as the magnetic sensor 30 disposed on the side of the magnetic encoder 2, an AMR (Anisotropic magnetoresistive) sensor or a TMR (Tunneling magnetoresistive) sensor may be used as the magnetic sensor 30 disposed on the side opposite to the magnetic encoder 2.

Further, for example, when the rotation speed (wheel rotation speed) of the inner wheel 11 with respect to the outer wheel 12 is required to be detected with higher accuracy when the detection result of the rotation speed (wheel rotation speed) of the inner wheel 11 with respect to the outer wheel 12 is used in a vehicle body stability control device, an indirect inflation pressure detection device, or the like, a GMR sensor or an AMR sensor may be used as the magnetic sensor 30 disposed on the side of the magnetic encoder 2, and a TMR sensor having higher sensitivity than the GMR sensor or the AMR sensor may be used as the magnetic sensor 30 disposed on the side opposite to the magnetic encoder 2. It is also possible to use the same kind of magnetic sensor 30 having different sensitivities, for example, a GMR sensor as the magnetic sensor 30 disposed on the magnetic encoder 2 side and a GMR sensor having a higher sensitivity than the GMR sensor disposed on the magnetic encoder 2 side as the magnetic sensor 30 disposed on the side opposite to the magnetic encoder 2. The indirect inflation pressure detecting device is a device that detects the occurrence of a tire burst or the like on any wheel by comparing the rotation speeds (wheel rotation speeds) of 4 wheels of the vehicle.

In the case of using 3 or more magnetic sensors 30, the sensitivity is preferably higher as the distance from the magnetic encoder 2 increases. More specifically, the sensitivity of the magnetic sensor 30 other than the magnetic sensor 30 disposed closest to the magnetic encoder 2 is preferably equal to or higher than the sensitivity of the magnetic sensor 30 disposed closer to the magnetic encoder 2 than the magnetic sensor 30. That is, for example, in the case of using 4 magnetic sensors 30, it is also possible to use hall ICs of the same sensitivity as the 2 magnetic sensors 30 disposed closer to the magnetic encoder 2, and to use GMR sensors of the same sensitivity as the 2 magnetic sensors 30 disposed farther from the magnetic encoder 2.

The outer shell 31 is formed integrally with a substantially cylindrical main body 310 that covers the magnetic sensor 30 and the end of the cable 4, and a flange 311 that fixes the sensor 3 to the knuckle 9. A bolt hole 312 is formed in the flange portion 311, the bolt hole 312 is used for penetrating a bolt 92 (see fig. 1) for fixing the sensor portion 3 to the knuckle 9, and a metal collar (collar)313 is provided along an inner circumferential surface of the bolt hole 312 in the bolt hole 312, and the collar is used for suppressing deformation of the flange portion 311 at the time of fastening the 313 bolt.

An opposing surface 314 that faces the magnetic encoder 2 is formed at the distal end portion (the end portion on the opposite side to the extending side of the cable 4) of the body portion 310 of the housing portion 31. The sensor unit 3 is fixed to the knuckle 9 in a state where the facing surface 314 faces the magnetic encoder 2 (in a state where the facing surface faces in the axial direction parallel to the rotation axis O).

As the housing portion 31, for example, a housing portion formed of PA (polyamide) 612, nylon 66 (nylon is a registered trademark), PBT (polybutylene terephthalate), or the like can be used. In the present embodiment, as the resin used for the housing portion 31, a resin in which a glass filler is mixed in PA612 is used.

(modification of sensor-equipped cable 100)

In the above embodiment, the cable 4 is a cable in which the 2 pairs of electric wires 41 are collectively covered with the sheath 42, but the cable 4 is not limited thereto, and may include electric wires other than the electric wires 41 for the sensor unit 3.

In sensor-equipped cable 100a shown in fig. 5A and 5B, cable 4a includes: the electric cord comprises 2 twisted wires 43 formed by twisting 1 pair of electric wires 41, a pair of power cords 7 having an outer diameter and a conductor cross-sectional area larger than those of the electric wires 41, a band member 45 spirally wound around an aggregate 44 formed by twisting two twisted wires 43 and the power cords 7, and a sheath 42 covering the outer periphery of the band member 45.

The sensor unit 3 is provided at one end of each of the two twisted pairs 43. A vehicle body side sensor connector 75 for connecting to a group of wires provided in a relay box of a vehicle body is attached to the other end portions of the two twisted pairs 43.

In the present embodiment, the power supply line 7 includes a power supply line for supplying a driving current to an electric motor (not shown) for an electric parking brake (hereinafter, EPB) mounted on a wheel of a vehicle.

The EPB means an electric brake device including: when the parking brake operation switch is operated to switch from the off state to the on state when the vehicle is stopped, a drive current is output to the electric motor for a predetermined time (for example, 1 second), and the electric motor causes the brake pad to be pressed against the disc rotor of the wheel, thereby generating a braking force in the wheel. Further, the EPB is configured to: when a parking brake operation switch is operated to change from an on state to an off state or when an accelerator pedal is depressed, a drive current is output to an electric motor to separate a brake pad from a disc rotor of a wheel, thereby releasing a braking force applied to the wheel. That is, the operating state of the EPB is maintained from when the parking brake operation switch is on until when the parking brake operation switch is off or the accelerator pedal is depressed.

The power supply line 7 includes a power supply line central conductor 71, and a power supply line insulator 72 covering an outer periphery of the power supply line central conductor 71. The power-line central conductor 71 is formed of a twisted conductor obtained by twisting a bare wire having good conductivity such as copper, and the power-line insulator 72 is formed of an insulating resin such as crosslinked polyethylene.

A wheel-side power connector 73a for connection to the EPB electric motor is attached to one end of the pair of power lines 7, and a vehicle-body-side power connector 73b for connection to the set of electric wires in the relay box is attached to the other end of the 1 pair of power lines 7.

The assembly 44 is configured by twisting 1 pair of power supply lines 7 with two pairs of twisted wires 43. In the present embodiment, the power supply line 7 is arranged between two twisted pairs 43 in the circumferential direction. In the cross section of fig. 5B, one twisted pair 43, one power supply line 7, the other twisted pair 43, and the other power supply line 7 are arranged in this order in the clockwise direction.

In addition, in the case where the power supply lines 7 are arranged so as to be adjacent in the circumferential direction (in the case where two twisted pairs 43 are arranged so as to be adjacent), the center of gravity of the aggregate 44 is greatly displaced from the center position of the aggregate 44, and if the aggregate 44 is configured by twisting the two twisted pairs 43 and the power supply lines 7 in this state, the aggregate 44 is in a twisted state as a whole. Therefore, it is difficult to manufacture the linear cable 4a, and a problem of a decrease in flexibility occurs such as a direction in which bending is not easily generated in a part of the longitudinal direction. As in the present embodiment, by configuring the twisted pair wires 43 and the power supply line 7 to be alternately arranged in the circumferential direction, it is possible to easily realize the linear cable 4a, and it is possible to suppress a problem that a direction in which bending is not easily generated in a part in the longitudinal direction, and to suppress a decrease in flexibility.

In addition, in the EPB, basically, a drive current is supplied to the electric motor when the vehicle is stopped. On the other hand, the rotation detecting device 1 is used when the vehicle is traveling, and the rotation detecting device 1 is not used when the drive current is supplied to the power supply line 7. Therefore, in the present embodiment, the shield conductor provided around the power supply line 7 and the twisted pair wire 43 is omitted. By omitting the shield conductor, the outer diameter of the cable 4a can be reduced as compared with the case where the shield conductor is provided, and the number of components can be reduced to suppress the cost.

In the present embodiment, the two twisted pairs 43 that transmit electric signals when the vehicle is traveling are separated mainly by the pair of power supply lines 7 that supply drive current to the electric motor after the vehicle is stopped. Thus, even if the shield conductor provided around the twisted pair 43 is omitted, crosstalk between the two twisted pair 43 can be reduced.

A plurality of filamentary (fibrous) interposers extending in the longitudinal direction of the cable 4a may be disposed between the two twisted pairs 43 and the power supply line 7 and the tape member 45 (interposed therebetween). In this case, the aggregate 44 is preferably formed by twisting the intermediate together with the two twisted pairs 43 and the power supply line 7. This makes it possible to make the cross-sectional shape of the belt member 45 wound around the outer periphery of the assembly 44 closer to a circular shape. As the intermediate, a fibrous material such as polypropylene yarn, chemical fiber spun yarn (rayon staple fiber), aramid fiber, nylon fiber, or fiber-based plastic, paper, or cotton yarn can be used.

A tape member 45 is spirally wound around the assembly 44, and the tape member 45 is in contact with all the electric wires (4 electric wires 41 and 1 to the power supply line 7) covered with the tape member 45. The belt member 45 is interposed between the aggregate 44 and the sheath 42, and functions to reduce friction between the aggregate 44 (the electric wire 41 and the power supply line 7) and the sheath 42 during bending. That is, by providing the band member 45, friction between the electric wire 41, the power line 7, and the sheath 42 can be reduced without using a lubricant such as talc powder, and pressure applied to the electric wire 41 and the power line 7 during bending can be reduced, thereby improving bending resistance.

As the tape member 45, a tape member (a tape member having a small friction coefficient) that is easily slidable with respect to the insulator 41b of the electric wire 41 and the insulator 72 for the power cord of the power cord 7 is desirably used, and for example, a tape member formed of a nonwoven fabric, paper, or resin (resin film or the like) may be used. The belt member 45 is spirally wound around the aggregate 44 so that a part of the belt member in the width direction (a direction perpendicular to the longitudinal direction and the thickness direction of the belt member 45) overlaps with each other. In addition, the portions of the belt members 45 that overlap each other are not bonded by an adhesive or the like.

(action and Effect of the embodiment)

As described above, in the rotation detecting device 1 according to the present embodiment, the sensor unit 3 includes the plurality of magnetic sensors 30, the magnetic sensors 30 include the plate-shaped detecting unit 300, and the detecting unit 300 includes: each of the detecting units 300 is laminated in a direction in which the sensor unit 3 and the magnetic encoder 2 face each other, and includes a magnetic detecting element that detects a magnetic field from the magnetic encoder 2, a signal processing circuit that processes a signal output from the magnetic detecting element, and a resin mold 300a that covers the magnetic detecting element and the signal processing circuit together.

Thus, even when a plurality of magnetic sensors 30 are used for redundancy or to improve detection accuracy, the sensor unit 3 can be made small, and even when the gap between the sensor unit 3 and the magnetic encoder 2 is large or the lamination interval of the detection unit 300 is large, for example, detection can be performed using the plurality of magnetic sensors 30.

In the present embodiment, the magnetic sensor 30 disposed farthest from the magnetic encoder 2 has higher sensitivity than the magnetic sensor 30 disposed closest to the magnetic encoder 2. For example, when 2 magnetic sensors 30 are used, it is also conceivable to use a magnetic sensor having sufficiently high sensitivity as both of the magnetic sensors 30. However, since the magnetic sensor 30 having high sensitivity is expensive, the cost of the rotation detecting device 1 increases. According to the present embodiment, the highly reliable rotation detection device 1 using the plurality of magnetic sensors 30 can be realized while suppressing the cost.

(summary of embodiment)

Next, technical ideas that can be grasped from the above-described embodiments will be described by reference to symbols and the like in the embodiments. In the following description, the reference numerals and the like do not limit the components in the claims to those specifically shown in the embodiments.

[1] A rotation detecting device 1 includes:

a detected member 2 attached to the rotating member 11 and having a plurality of magnetic poles arranged along a circumferential direction around a rotation axis of the rotating member 11, and

a sensor unit 3 attached to a fixed member 9 that does not rotate with the rotation of the rotating member 11 and disposed to face the member to be detected 2,

the sensor unit 3 includes a plurality of magnetic sensors 30, the magnetic sensors 30 include a plate-shaped detection unit 300, and the detection unit 300 includes: a magnetism detection element for detecting a magnetic field from the detection target member 2, a signal processing circuit for processing a signal output from the magnetism detection element, and a covering body 300a for covering the magnetism detection element and the signal processing circuit together,

the detection units 300 are stacked in a direction in which the sensor unit 3 and the detection target member 2 face each other.

[2] According to the rotation detecting device 1 described in [1], the magnetic sensor 30 disposed farthest from the detection target member 2 has higher sensitivity than the magnetic sensor 30 disposed closest to the detection target member 2.

[3] According to the rotation detecting device 1 of [2], the sensor unit 3 includes 2 magnetic sensors 30, the magnetic sensor 30 disposed on the side of the detected member 2 includes a hall IC, and the magnetic sensor 30 disposed on the side opposite to the detected member 2 includes a GMR sensor, an AMR sensor, or a TMR sensor.

[4] According to the rotation detecting device 1 of [2], the sensor unit 3 includes 2 magnetic sensors 30, the magnetic sensor 30 disposed on the side of the detected member 2 includes a GMR sensor or an AMR sensor, and the magnetic sensor 30 disposed on the side opposite to the detected member 2 includes a TMR sensor.

[5] A sensor-equipped cable 100 used for a rotation detection device 1, the rotation detection device 1 comprising: a member to be detected 2 attached to a rotating member 11 and provided with a plurality of magnetic poles along a circumferential direction around a rotation axis of the rotating member 11, and a sensor unit 3 attached to a fixed member 9 that does not rotate with the rotation of the rotating member 11 and disposed so as to face the member to be detected 2,

the sensor-equipped cable 100 includes a cable 4 and the sensor unit 3 provided at an end of the cable 4,

the sensor unit 3 includes a plurality of magnetic sensors 30, the magnetic sensors 30 include a plate-shaped detection unit 300, and the detection unit 300 includes: a magnetism detection element for detecting a magnetic field from the detection target member 2, a signal processing circuit for processing a signal output from the magnetism detection element, and a covering body 300a for covering the magnetism detection element and the signal processing circuit together,

the detection units 300 are stacked in a direction in which the sensor unit 3 and the detection target member 2 face each other.

[6] According to the sensor-equipped cable 100 described in item [5], the magnetic sensor 30 disposed farthest from the detection target member 2 has higher sensitivity than the magnetic sensor 30 disposed closest to the detection target member 2.

[7] The sensor-equipped cable 100a according to item [5] or [6], in which the rotation detection device 1 detects the rotation speed of the rotating member 11 that rotates together with the vehicle wheel, and the cable 4 includes: a plurality of pairs of electric wires 41 corresponding to the plurality of magnetic sensors 30, a power supply line 7 for supplying a driving current to an electric motor for electric parking brake mounted on the wheel, and a sheath 42 for covering the plurality of pairs of electric wires 41 and the power supply line 7 together.

The embodiments of the present invention have been described above, but the embodiments described above do not limit the invention according to the claims. Note that not all of the combinations of the features described in the embodiments are essential to means for solving the problems of the invention.

The present invention can be implemented with appropriate modifications without departing from the spirit thereof.

For example, in the above embodiment, the case where the rotation detecting device 1 is a device that detects the wheel rotation speed has been described, but the present invention is not limited to this, and for example, the present invention can be applied to a drive shaft sensor, a crank angle sensor, and the like.