JP7173242B2 - cable with sensor - Google Patents

Description

The present invention relates to cables with sensors.

2. Description of the Related Art Conventionally, there has been known a rotation detection device that is used in, for example, a bearing unit of a wheel and detects the rotation speed of a rotating member that rotates together with the wheel (see, for example, Patent Document 1).

In Patent Document 1, a member to be detected that is attached to a rotating member and has a plurality of magnetic poles along the circumferential direction of the rotating member, and a fixed member that rotatably supports the rotating member is attached to the magnetic field of the member to be detected. and a magnetic sensor having a sensing element for sensing.

JP 2013-47636 A

By the way, as described above, in the rotation detection device for measuring the rotation speed of the wheel, it is possible to detect the rotation speed of the wheel even if the magnetic sensor fails, or to detect the rotation speed of the wheel more accurately. There is a desire to use multiple magnetic sensors as much as possible.

When a plurality of magnetic sensors are mounted in the sensor section, the size of the entire sensor section becomes large, and there is a possibility that, for example, the sensor section cannot be inserted into the holding hole that holds the sensor section. Therefore, even when a plurality of magnetic sensors are mounted, there has been a demand to keep the size of the sensor unit small.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a sensor-equipped cable capable of reducing the size of a sensor unit while having a plurality of magnetic sensors.

An object of the present invention is to solve the above-described problems. a sensor unit that is attached to a fixed member that does not rotate along with the rotation of the rotating member and is arranged to face the member to be detected, wherein the sensor unit detects a magnetic field from the member to be detected. a plate-shaped detection section having a cover body covering the magnetic detection element and the signal processing circuit for processing the signal output from the magnetic detection element, and the magnetic detection element and the signal processing circuit collectively. each of the detection units is stacked in a direction in which the sensor unit and the member to be detected are opposed to each other, and the magnetic sensor positioned farthest from the member to be detected Provided is a rotation detection device having higher sensitivity than the magnetic sensor arranged closest to the member to be detected.

Further, in order to solve the above-mentioned problems, the present invention provides a member to be detected which is attached to a rotating member and has a plurality of magnetic poles provided along the circumferential direction about the rotating shaft of the rotating member. and a sensor unit that is attached to a fixed member that does not rotate with the rotation of the rotating member and is arranged to face the member to be detected, wherein the cable is used in a rotation detection device, , a cable, and the sensor section provided at the end of the cable, wherein the sensor section detects the magnetic field from the member to be detected, and the magnetic field output from the magnetic detection element A signal processing circuit for processing signals, and a plurality of magnetic sensors having a plate-shaped detection unit having a resin mold that collectively covers the magnetic detection element and the signal processing circuit, wherein each detection unit and a cable with a sensor, which is laminated in a direction in which the sensor section and the member to be detected face each other.

ADVANTAGE OF THE INVENTION According to this invention, the cable with a sensor which can make a sensor part small can be provided, even if it has several magnetic sensors.

1 is a sectional view showing a configuration example of a rotation detection device according to an embodiment of the present invention and a wheel bearing device for a vehicle having this rotation detection device; It is a perspective view of a sensor part. (a) is a side view of the sensor unit, and (b) is a broken cross-sectional view showing a cross section of the housing. (a) is a top view of the sensor portion, (b) is a broken cross-sectional view showing a cross section of the housing, and (c) is a top view of the magnetic sensor and the electric wire. It is a figure which shows the cable with a sensor based on the modified example of this invention, (a) is a schematic block diagram, (b) is sectional drawing of a cable.

[Embodiment]
BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings.

(Configuration of Wheel Bearing Device 10)
FIG. 1 is a sectional view showing a configuration example of a rotation detection device according to the present embodiment and a wheel bearing device for a vehicle having this rotation detection 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 to which a wheel is attached; A pair of raceway surfaces 11b, 11b formed on the outer peripheral surface 11a of the outer ring 12 and a pair of raceway surfaces 12b, 12b formed on the inner peripheral surface 12a of the outer ring 12. and a rotation detection device 1 for detecting the rotational speed of the inner ring 11 with respect to the outer ring 12 (that is, the wheel speed).

A through hole is formed along the rotation axis O in the central portion of the 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 this through hole. ing. The pair of raceway surfaces 11b, 11b of the inner ring 11 are formed parallel to each other so as to extend in the circumferential direction.

A flange portion 111 of the inner ring 11 is provided integrally with the body portion 110 so as to protrude radially outward of the body portion 110 . The flange portion 111 is formed with a plurality of through holes 111a into which bolts for mounting wheels (not shown) are press-fitted.

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

The knuckle 9 is formed with a holding hole 90 for holding the sensor section 3 of the rotation detecting device 1 which will be described below. The holding hole 90 has a circular cross-sectional shape perpendicular to the central axis, and penetrates the knuckle 9 in the radial direction of the rotation axis O. As shown in FIG.

(Explanation of Rotation Detection Device 1)
FIG. 2 is a perspective view of the sensor section. FIG. 3(a) is a side view of the sensor portion, and FIG. 3(b) is a broken cross-sectional view showing a cross section of the housing. 4(a) is a top view of the sensor section, FIG. 4(b) is a broken cross-sectional view showing a cross section of the housing, and FIG. 4(c) is a top view of the magnetic sensor and the electric wire.

As shown in FIGS. 1 to 4, the rotation detection device 1 is attached to an inner ring 11 as a rotating member, and has a plurality of magnetic poles (non-magnetic ) is provided as a member to be detected, and a sensor that is attached to a knuckle 9 as a fixed member that does not rotate with the rotation of the inner ring 11 and is arranged to face the magnetic encoder 2. Part 3;

The magnetic encoder 2 is formed in an annular shape having a thickness in a direction parallel to the rotation axis O. As shown in FIG. The magnetic encoder 2 is supported by a support member 112 fixed to the outer peripheral surface 11 a of the inner ring 11 and attached so as to rotate together with the inner ring 11 . The magnetic encoder 2 also has N magnetic poles and S magnetic poles that are alternately arranged along the circumferential direction so as to face the sensor section 3 .

The sensor section 3 is provided at the end of the cable 4 . The sensor-equipped cable 100 according to the present embodiment is the cable 4 provided with the sensor unit 3 at the end thereof. In the present embodiment, the magnetic encoder 2 and the tip of the sensor section 3 face each other in the axial direction parallel to the rotation axis O. As shown in FIG.

In the rotation detection device 1 according to the present embodiment, the sensor section 3 has a plurality of magnetic sensors 30 and a housing section 31 made of resin molding and covering the plurality of magnetic sensors 30 collectively. there is Here, a case where the sensor section 3 has two magnetic sensors 30 will be described.

The cable 4 has a plurality of pairs (here, two pairs) of electric wires 41 corresponding to the plurality of magnetic sensors 30 . Each electric wire 41 has a central conductor 41a made of a stranded wire conductor made by twisting strands of good conductivity such as copper, and the outer periphery of the central conductor 41a is covered with insulation made of an insulating resin such as crosslinked polyethylene. and a body 41b. Moreover, the cable 4 further has a sheath 42 that collectively covers the two pairs (four wires) of the electric wires 41 .

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

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

The detection unit 300 includes a magnetic detection element (not shown) that detects the magnetic field from the magnetic encoder 2, a signal processing circuit (not shown) that processes the signal output from the magnetic detection element, the magnetic detection element and the signal processing circuit. and a resin mold 300a as a covering body that collectively covers the above. The detection unit 300 is formed in a substantially rectangular plate shape in plan view (a shape in which one of four corners of a rectangle is chamfered). The detection axis (magnetic field detection direction) of the magnetic detection element is the vertical direction (direction tangential to the circle centered on the rotation axis O) in FIG. 4(a).

A pair of connection terminals 301 extends from one long side of the detection unit 300 (long side not connected to the chamfered corner) in a direction perpendicular to the long side. are formed parallel to each other. In the present embodiment, both connection terminals 301 are formed in a strip shape, and the central conductor 41a of the corresponding electric wire 41 is electrically connected to the leading end portion (the end portion on the side opposite to the detecting portion 300). there is

A pair of connection terminals 301 of one of the magnetic sensors 30 closer to the magnetic encoder 2 (lower magnetic sensor 30 in FIG. 3B) are arranged in the same direction as the extension direction of the central conductor 41a. They extend in parallel straight lines. On the other hand, a pair of connection terminals 301 of the other magnetic sensor 30 farther from the magnetic encoder 2 (the upper magnetic sensor 30 in FIG. 3B) are bent into a crank shape. Specifically, the pair of connection terminals 301 of the other magnetic sensor 30 has a portion extending parallel to the extension direction of the central conductor 41a from the connection portion with the central conductor 41a, and is bent from the portion to It has a portion extending in the direction of the magnetic sensor 30 (diagonally downward to the left in FIG. 3(b)), and further has a portion bent from the portion and extending parallel to the extending direction of the central conductor 41a. .

Although not shown, a capacitive element for suppressing noise is connected between the two connection terminals 301, and the capacitive element and the connection terminal 301 connected to the capacitive element are covered. , a capacitive element protection portion 302 formed by resin molding is provided. The capacitive element protection portion 302 provided in the other magnetic sensor 30 is provided between the pair of connection terminals 301 of one magnetic sensor 30 and the pair of connection terminals 301 of the other magnetic sensor 30 . and the pair of crank-shaped connection terminals 301 are arranged while making effective use of the space.

In the rotation detection device 1 according to the present embodiment, the detection units 300 of the plurality (here, two) of the magnetic sensors 30 are stacked in the facing direction of the sensor unit 3 and the magnetic encoder 2 . Further, the detection units 30 are stacked in a direction that intersects (perpendicular to in this embodiment) the direction in which the cable 4 is led out from the housing portion 31 . Further, in the present embodiment, the magnetic sensor 30 arranged furthest from the magnetic encoder 2 has higher sensitivity than the magnetic sensor 30 arranged closest to the magnetic encoder 2 . When the cable 4 is bent and resin-molded along with the bent portion of the cable 4 to form the L-shaped housing portion 30, each detection portion 30 is arranged in the lead-out direction in which the cable 4 is led out from the housing portion 31. are stacked in the same direction as

The detection portions 300 of both magnetic sensors 30 are stacked in the thickness direction. That is, in the present embodiment, the direction in which the sensor section 3 and the magnetic encoder 2 face each other coincides with the thickness direction (laminating direction) of the detection section 300 . The direction in which the sensor section 3 and the magnetic encoder 2 face each other does not need to be exactly the same as the thickness direction (laminating direction) of the detection section 300, and may be slightly different. In other words, "each detection unit 300 is laminated in the facing direction of the sensor unit 3 and the magnetic encoder 2" means that the facing direction of the sensor unit 3 and the magnetic encoder 2 is the same as the lamination direction of the detection unit 300. A deviation of several degrees (for example, about ±10°) is also included.

In the present embodiment, since the magnetic encoder 2 and the tip of the sensor section 3 face each other in the axial direction parallel to the rotation axis O, the thickness direction (laminating direction) of the detection section 300 is aligned with the axial direction. I am doing it. However, not limited to this, for example, when the magnetic encoder 2 and the tip of the sensor unit 3 are opposed to each other in the radial direction perpendicular to the rotation axis O, the thickness direction (stacking direction) of the detection unit 300 is , should be aligned in the radial direction.

Further, in the present embodiment, both detection units 300 are directly laminated. That is, the surface of one detection unit 300 and the surface of the other detection unit 300 are in contact. As a result, the size can be reduced compared to the case where both detection units 300 are spaced apart, and the distance between the magnetic detection elements in both detection units 300 can be easily maintained constant. Detection accuracy can be improved by minimizing the distance from the magnetic sensor 30 to the magnetic encoder 2, which is arranged further away. In the present embodiment, both detectors 300 are not adhered and fixed by an adhesive or the like, and both detectors 300 are held in the housing part 31 in a laminated state.

Moreover, it is desirable that both detection units 300 are laminated so that at least a part of both magnetic detection elements overlap in the direction (axial direction) in which the sensor unit 3 and the magnetic encoder 2 face each other.

Using a plurality of magnetic sensors 30 makes it possible to continue detection using other magnetic sensors 30 even if one magnetic sensor 30 fails, improving the reliability of the rotation detection device 1 .

In addition, by stacking the detection units 300 (stacking them in the thickness direction), the plurality of magnetic sensors 30 can be arranged more compactly than, for example, when the sensor units 3 are arranged side by side in the width direction perpendicular to the thickness direction. Therefore, even when a plurality of magnetic sensors 30 are used, the entire sensor section 3 can be kept small.

The thickness of the detection unit 300 is, for example, about 1 mm. If the target is too large, the strength of the magnetic field detected by the magnetic sensor 30 located at a distance 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 arranged furthest from the magnetic encoder 2 is made higher than the sensitivity of the magnetic sensor 30 arranged closest to the magnetic encoder 2 . When two magnetic sensors 30 are used as in the present embodiment, the magnetic sensor 30 arranged on the opposite side of the magnetic encoder 2 should have a higher sensitivity than the magnetic sensor 30 arranged on the magnetic encoder 2 side. will be used.

Here, "high sensitivity" means that a smaller magnetic field strength can be detected. In other words, "high sensitivity" means that the minimum detectable magnetic field strength is smaller.

In the present embodiment, a Hall IC is used as the magnetic sensor 30 arranged on the side of the magnetic encoder 2, and a GMR (Giant Magneto Resistive Sensor) having higher sensitivity than the Hall IC is used as the magnetic sensor 30 arranged on the opposite side of the magnetic encoder 2. effect) sensor was used. When a Hall IC is used as the magnetic sensor 30 arranged on the side of the magnetic encoder 2, the magnetic sensor 30 arranged on the side opposite to the magnetic encoder 2 may be an AMR (Anisotropic Magneto Resistive) sensor or a TMR (Tunneling Magneto Resistive) sensor. A sensor may be used.

Further, for example, when the detection result of the rotation speed (wheel speed) of the inner ring 11 with respect to the outer ring 12 is used for a vehicle body stability control device or an indirect air pressure detection device, the rotation speed (wheel speed) of the inner ring 11 with respect to the outer ring 12 can be increased. When accurate detection is required, a GMR sensor or an AMR sensor is used as the magnetic sensor 30 arranged on the side of the magnetic encoder 2, and a GMR sensor is used as the magnetic sensor 30 arranged on the opposite side of the magnetic encoder 2. A TMR sensor, which has a higher sensitivity than the AMR sensor, may also be used. For example, a GMR sensor is used as the magnetic sensor 30 arranged on the side of the magnetic encoder 2, and the sensitivity of the magnetic sensor 30 arranged on the side opposite to the magnetic encoder 2 is higher than that of the GMR sensor arranged on the side of the magnetic encoder 2. It is also possible to use the same type of magnetic sensor 30 with different sensitivities, such as using a high GMR sensor. The indirect air pressure detection device detects the occurrence of a puncture in any wheel by comparing the number of revolutions (wheel speed) of four wheels of the vehicle.

When three or more magnetic sensors 30 are used, it is preferable that the sensitivity increases as the distance from the magnetic encoder 2 increases. More specifically, the sensitivity of the magnetic sensors 30 other than the magnetic sensor 30 arranged closest to the magnetic encoder 2 is greater than or equal to the sensitivity of the magnetic sensor 30 arranged closer to the magnetic encoder 2 than the magnetic sensor 30 concerned. Good to have. That is, for example, when four magnetic sensors 30 are used, Hall ICs with the same sensitivity are used as the two magnetic sensors 30 arranged closer to the magnetic encoder 2, and the two magnetic sensors 30 arranged further apart from the magnetic encoder 2 are used. It is also possible to use a GMR sensor with the same sensitivity as the magnetic sensor 30 .

The housing portion 31 integrally includes a substantially cylindrical body portion 310 that collectively covers the magnetic sensor 30 and the ends of the cables 4, and a flange portion 311 for fixing the sensor portion 3 to the knuckle 9. It becomes The flange portion 311 is formed with a bolt hole 312 for passing a bolt 92 (see FIG. 1) for fixing the sensor portion 3 to the knuckle 9. A collar 313 made of metal for suppressing deformation of the flange portion 311 during bolting is provided so as to follow.

A facing surface 314 facing the magnetic encoder 2 is formed at the tip of the body portion 310 of the housing portion 31 (the end on the side opposite to the extension side of the cable 4). The sensor unit 3 is fixed to the knuckle 9 with the facing surface 314 facing the magnetic encoder 2 (in the axial direction parallel to the rotation axis O).

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

(Modified example of cable 100 with sensor)
In the above-described embodiment, the cable 4 has two pairs of wires 41 collectively covered with the sheath 42, but the cable 4 is not limited to this, and the cable 4 may include wires other than the wires 41 for the sensor section 3. may contain.

In the sensor-equipped cable 100a shown in FIGS. 5(a) and 5(b), the cable 4a includes two twisted pair wires 43 formed by twisting a pair of electric wires 41, and an outer diameter and a conductor cross-sectional area larger than those of the electric wires 41. A large pair of power wires 7, a tape member 45 spirally wound around an assembly 44 formed by twisting both twisted pairs 43 and the power wires 7, and the outer periphery of the tape member 45 is coated and a sheath 42 which is in contact with.

A sensor section 3 is provided at one end of both twisted pair wires 43 . A body-side sensor connector 75 is attached to the other end of both twisted wire pairs 43 for connection to a wire group in a junction box provided in the body of the vehicle.

In this embodiment, the power line 7 is a power line for supplying drive current to an electric motor (not shown) for an electric parking brake (EPB) mounted on the wheels of the vehicle.

EPB means that when the parking brake activation switch is turned on from the off state while the vehicle is stopped, a drive current is output to the electric motor for a predetermined period of time (for example, one second) so that the brake pads are applied by the electric motor. This is an electric braking device that generates a braking force on the wheel when pressed against the disk rotor of the wheel. Also, in the EPB, when the parking brake activation switch is turned from the ON state to the OFF state, or when the accelerator pedal is stepped on, a drive current is output to the electric motor to move the brake pads from the disk rotors of the wheels. It is configured to move away to release the braking force on the wheels. In other words, the operating state of the EPB is maintained after the parking brake activation switch is turned on until the parking brake activation switch is turned off or the accelerator pedal is depressed.

The power line 7 has a power line center conductor 71 and a power line insulator 72 covering the outer circumference of the power line center conductor 71 . The power line central conductor 71 is made of a twisted wire conductor made by twisting strands of good conductivity such as copper, and the power line insulator 72 is made of an insulating resin such as crosslinked polyethylene.

One end of the pair of power wires 7 is attached with a wheel-side power connector 73a for connection with an electric motor for EPB, and the other end of the pair of power wires 7 is connected to a wire group in the relay box. A vehicle body side power connector 73b is attached for connection to the .

The assembly 44 is configured by twisting both twisted wire pairs 43 and a pair of power wires 7 . In the present embodiment, the power line 7 is arranged between the two twisted wire pairs 43 in the circumferential direction. In the cross section of FIG. 7B, one twisted pair wire 43, one power wire 7, the other twisted pair wire 43, and the other power wire 7 are sequentially arranged in the clockwise direction.

When the power wires 7 are arranged adjacent to each other in the circumferential direction (when both the twisted pair wires 43 are arranged adjacent to each other), the center of gravity of the aggregate 44 deviates greatly from the central position of the aggregate 44. In this state, if the twisted pair wires 43 and the power supply wire 7 are twisted together to form the assembly 44, the assembly 44 will be twisted as a whole. As a result, it becomes difficult to fabricate a straight cable 4a, and there is a problem that the flexibility of the cable 4a is lowered because there are some directions in which it is difficult to bend the cable 4a in the longitudinal direction. As in this embodiment, the twisted pair wires 43 and the power wires 7 are arranged alternately in the circumferential direction, so that the straight cable 4a can be easily realized, and a part of the longitudinal direction It is possible to suppress the problem of occurrence of a direction in which it is difficult to bend in the direction, and suppress the decrease in flexibility.

Note that the EPB basically supplies drive current to the electric motor when the vehicle is stopped. On the other hand, the rotation detection device 1 is used when the vehicle is running, and the rotation detection 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, it is possible to reduce the outer diameter of the cable 4a compared to the case where the shield conductor is provided, and it is also possible to reduce the number of parts and suppress the cost.

Further, in the present embodiment, the twisted wire pair 43 for transmitting electrical signals during running of the vehicle is spaced apart by the pair of power wires 7 that supply drive current to the electric motor mainly after the vehicle is stopped. This makes it possible to reduce crosstalk between both twisted pair wires 43 even if shield conductors provided around the twisted pair wires 43 are omitted.

A plurality of thread-like (fiber-like) interpositions extending in the longitudinal direction of the cable 4 a may be arranged between the twisted pair wires 43 , the power wire 7 and the tape member 45 . In this case, it is preferable to construct the assembly 44 by twisting this interposition, both twisted pair wires 43 and the power supply wire 7 together. As a result, the cross-sectional shape when the tape member 45 is wound around the outer periphery of the assembly 44 can be made closer to a circular shape. As an intervening material, fibrous bodies such as polypropylene yarn, staple 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 contacts all the electric wires (the four electric wires 41 and the pair of power wires 7) covered by the tape member 45. ing. The tape member 45 is interposed between the assembly 44 and the sheath 42 and serves to reduce friction between the assembly 44 (the electric wire 41 and the power supply wire 7) and the sheath 42 during bending. That is, by providing the tape member 45, the friction between the electric wire 41 or the power wire 7 and the sheath 42 is reduced without using a lubricant such as talc powder, and the stress applied to the electric wire 41 or the power wire 7 when bending is reduced. It is possible to reduce it and improve the bending resistance.

As the tape member 45, it is desirable to use a material that is slippery (having a small coefficient of friction) with respect to the insulator 41b of the electric wire 41 and the power line insulator 72 of the power line 7. For example, nonwoven fabric, paper, Alternatively, one made of resin (resin film, etc.) can be used. The tape member 45 is spirally wound around the assembly 44 so that a portion of the tape member 45 in the width direction (the direction perpendicular to the longitudinal direction and thickness direction of the tape member 45) overlaps. Note that the portion where the tape member 45 overlaps is not adhered with an adhesive or the like.

(Actions and effects of the embodiment)
As described above, in the rotation detection device 1 according to the present embodiment, the sensor unit 3 includes a magnetic detection element that detects the magnetic field from the magnetic encoder 2, and a signal processing circuit that processes the signal output from the magnetic detection element. , and a plurality of magnetic sensors 30 each having a plate-shaped detection unit 300 having a resin mold 300a that collectively covers the magnetic detection element and the signal processing circuit. They are stacked in the direction facing the encoder 2 .

As a result, even when a plurality of magnetic sensors 30 are used for redundancy or improved detection accuracy, the size of the sensor section 3 can be reduced, and, for example, the gap between the sensor section 3 and the magnetic encoder 2 can be reduced. is large, and even if the stacking interval of the detection unit 300 is large, detection using a plurality of magnetic sensors 30 is possible.

Further, in the present embodiment, the magnetic sensor 30 arranged furthest from the magnetic encoder 2 has higher sensitivity than the magnetic sensor 30 arranged closest to the magnetic encoder 2 . For example, when two magnetic sensors 30 are used, it is conceivable that both magnetic sensors 30 have sufficiently high sensitivity. However, since the highly sensitive magnetic sensor 30 is expensive, the cost of the rotation detection device 1 increases. According to the present embodiment, it is possible to realize a highly reliable rotation detection device 1 using a plurality of magnetic sensors 30 while suppressing costs.

(Summary of embodiment)
Next, technical ideas understood from the embodiments described above will be described with reference to the reference numerals and the like in the embodiments. However, each reference numeral and the like in the following description do not limit the constituent elements in the claims to the members and the like specifically shown in the embodiment.

[1] 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 the rotation axis of the rotating member (11); (11) is attached to a fixed member (9) that does not rotate along with the rotation of (11), and is provided with a sensor section (3) arranged facing the member to be detected (2), and the sensor section ( 3) includes a magnetic detection element for detecting the magnetic field from the member to be detected (2), a signal processing circuit for processing the signal output from the magnetic detection element, and the magnetic detection element and the signal processing circuit collectively. a plurality of magnetic sensors (30) having a plate-like detection part (300) having a cover (300a) that covers the sensor part (3) and the A rotation detection device (1) stacked in a direction facing a member to be detected (2).

[2] The magnetic sensor (30) arranged farthest from the member (2) to be detected is arranged more than the magnetic sensor (30) arranged closest to the member (2) to be detected. The rotation detector (1) according to [1], which has high sensitivity.

[3] The sensor section (3) has two magnetic sensors (30), and the magnetic sensor (30) arranged on the side of the detected member (2) is a Hall IC. The rotation detection device (1) according to [2], wherein the magnetic sensor (30) arranged on the opposite side of the detection member (2) consists of a GMR sensor, an AMR sensor or a TMR sensor.

[4] The sensor section (3) has two magnetic sensors (30), and the magnetic sensor (30) arranged on the detected member (2) side is a GMR sensor or an AMR sensor. , The rotation detecting device (1) according to [2], wherein the magnetic sensor (30) arranged on the side opposite to the member to be detected (2) is a TMR sensor.

[5] 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 the rotating shaft of the rotating member (11); A rotation detection device ( A cable (100) with a sensor used in 1), comprising a cable (4) and the sensor section (3) provided at the end of the cable (4), wherein the sensor section (3 ) integrates a magnetic detection element for detecting the magnetic field from the member to be detected (2), a signal processing circuit for processing the signal output from the magnetic detection element, and the magnetic detection element and the signal processing circuit. a plurality of magnetic sensors (30) each having a plate-shaped detection part (300) having a cover (300a) covering the surface of the magnetic sensor, and each detection part (300) includes the sensor part (3) and the subject. A sensor-equipped cable (100) laminated in a direction facing a detection member (2).

[6] The magnetic sensor (30) arranged farthest from the member (2) to be detected is arranged more closely than the magnetic sensor (30) arranged closest to the member (2) to be detected. The sensor-equipped cable (100) according to [5], which has high sensitivity.

[7] The rotation detection device (1) detects the rotation speed of the rotating member (11) that rotates with the wheels of the vehicle, and the cable (4) is connected to the plurality of magnetic sensors (30). A plurality of pairs of corresponding electric wires (41), a power supply line (7) for supplying a drive current to the electric motor for the electric parking brake mounted on the wheel, the plurality of pairs of electric wires (41) and the A cable with a sensor (100a) according to [5] or [6], comprising a sheath (42) collectively covering the power line (7).

Although the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the scope of claims. Also, it should be noted that not all combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

The present invention can be appropriately modified and implemented without departing from the gist thereof.

For example, in the above-described embodiment, the rotation detection device 1 detects the wheel speed. be.

1... Rotation detection device 2... Magnetic encoder (member to be detected)
3... Sensor part 30... Magnetic sensor 300... Detection part 300a... Resin mold (cover)
301... Connection terminal 31... Housing part 4... Cable 9... Knuckle (fixing member)
10... Wheel bearing device 11... Inner ring (rotating member)
12... Outer ring 13... Rolling element 100... Cable with sensor

Claims (5)

a cable;
a sensor unit provided at the end of the cable;
has
The sensor unit is
a plurality of magnetic sensors each having a detection unit having a magnetic detection element and a cover covering the magnetic detection element;
a housing covering the plurality of magnetic sensors and the cable;
has
The cable extends from the housing portion,
The sensor-equipped cable, wherein the detection units are arranged in a direction crossing a direction in which the cable extends from the housing unit. Used in a rotation detection device that detects the rotation speed of a rotating member,
Each of the detection units is arranged side by side with the rotating member in a direction intersecting with a direction in which the cable extends from the housing,
The cable with sensor according to claim 1. The sensor unit is inserted into a through hole formed in a fixed member that does not rotate with rotation of the rotating member,
The housing portion is inserted in a direction opposite to the extending direction of the cable from the housing portion,
The sensor-equipped cable according to claim 1 or 2. each of the plurality of magnetic sensors has a connection terminal extending from the detection unit;
The cable has a plurality of electric wires connected to the respective connection terminals of the plurality of magnetic sensors,
The sensor-equipped cable according to any one of claims 1 to 3. each of the detection units is in contact;
The sensor-equipped cable according to any one of claims 1 to 4.

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