JP2008256079A - Wheel supporting bearing unit with sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel supporting bearing unit with a sensor having a comparatively simple structure and excellent in waterproof and dust-proof properties that supports a drive wheel. <P>SOLUTION: The sensor 40 of the wheel supporting bearing unit 10 is equipped with: a case 41 having a cylindrical part 45 mounted to an outer ring 12 and an inward flange 42b extending from the cylindrical part 45; a holding part 42 mounted to the case 41 on the radially inner side of the cylindrical part 45 and the axially inner side of the inward flange 46, and in which a detection part 43 is embedded; an annular part 47 fitted to the outside of the inner ring 20 and disposed oppositely to the detection part 43 via an air gap g; and an encoder 44 having an outward flange 48 extending from the annular part 47. A labyrinth of a gap s1 narrower than the air gap g is formed of the inward flange 46 of the case 41 and the outward flange 48 of the encoder 44. On the abutting surface 50 of the cylindrical part 45 of the case 41 and the outer ring 12 of the holding part 42, a water draining passage 54 is formed whose maximum dimension is not larger than the air gap g. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wheel support bearing unit with a sensor, and more particularly to a wheel support bearing unit for rotatably supporting a wheel of an automobile or the like with respect to a suspension device, provided with a sensor for detecting the rotation speed of the wheel. The present invention relates to a wheel support bearing unit with a sensor.

  2. Description of the Related Art In recent years, anti-lock brake systems (ABS) that control so that wheels do not lock during braking and traction control systems that control so that wheels do not slip when starting have been adopted as techniques for improving the safety of automobiles. In these systems, in order to control the lock or slip of the wheel, a rotation sensor that accurately measures the rotation speed of the wheel is provided. Conventionally, various structures have been devised for attaching a rotation sensor to a wheel support bearing unit that supports a drive wheel (see, for example, Patent Documents 1 and 2).

  Further, in the wheel support bearing unit 100 described in Patent Document 1, as shown in FIG. 4, the seal device 110 in which the seal member 111 and the slinger 112 are combined is provided on the inboard side end of the outer member 101 (automobile). The rotation sensor 120 is mounted between the support ring body 103 press-fitted and fixed to the inner end of the vehicle in the vehicle width direction and the inner member 102 extending further outward in the axial direction than the outer member 101. Is disposed between the outer member 101 and the sealing device 110 in the axial direction. The rotation sensor 120 includes an encoder 121 that is directly attached to the outer peripheral surface of the inner member 102, and a sensor 122 that is attached to the support ring 103. A sensor pocket 104 and an engagement hole 105 are formed in the support ring body 103, and the sensor 122 is inserted into the sensor pocket 104, and a convex portion 123 provided in the sensor 122 is engaged with the engagement hole 105. It is fixed with.

In the wheel support bearing unit 100 a described in Patent Document 2, as shown in FIG. 5, the seal device 110 is mounted on the inboard side end between the outer member 101 and the inner member 102, and the rotation sensor 120. Is arranged axially outward of the sealing device 110. The encoder 121 of the rotation sensor 120 is attached to the side surface of the slinger 112, and the sensor 122 is inserted into the sensor pocket 104 of the support ring 103 that is press-fitted and fixed to the outer member 101, and a convex portion provided on the sensor 122. 123 is engaged with the engagement hole 105 and fixed to the support ring 103. Further, a rubber lip 124 that comes into contact with the outer peripheral surface of the rotating shaft 130 is bonded to the flange 106 on the inner diameter side of the support ring 103, and a space in which the sensor main body 125 and the encoder 121 are accommodated is sealed. .
JP 2000-225931 A (FIG. 3) Japanese Unexamined Patent Publication No. 2000-221202 (FIG. 12)

  By the way, as described above, the rotation sensor is attached to the inboard side end portion of the bearing unit that supports the drive wheel, so that it is exposed to the muddy water wound up by the constant velocity joint and is easily damaged by muddy water and dust. . In particular, when pebbles or the like are sandwiched between the sensor surface and the sensor rotor or encoder, the sensor surface is scratched and worn to destroy the sensor or wear the encoder surface and weaken the magnetic flux signal.

  In the wheel support bearing units 100 and 100a described in Patent Documents 1 and 2, a device for arranging the sensor 122 in the sealed space has been devised. However, the structure is complicated, and the sensor 122 and the sensor pocket 104 are arranged with each other. There is a problem that waterproofing is required newly. Further, when muddy water enters the sealed space where the sensor 122 is disposed, the sealed space becomes a water pool, which may adversely affect the detection accuracy of the sensor 122.

  The present invention has been made to eliminate such disadvantages, and an object of the present invention is to provide a wheel support bearing unit with a sensor that supports a drive wheel having a relatively simple structure and excellent waterproof and dustproof properties. There is to do.

The above object of the present invention is achieved by the following configurations.
(1) An outer member having first and second outer raceways on the inner peripheral surface;
A hub wheel having a wheel mounting flange for supporting the wheel at a portion near one end in the axial direction and having a first inner raceway surface on the outer peripheral surface and a small-diameter step formed on the hub wheel, An inner member comprising an inner ring having a second outer raceway surface on the surface;
A plurality of rolling elements arranged in a double row so as to roll freely between the first outer raceway and the first inner raceway and between the second outer raceway and the second inner raceway;
A sealing device for sealing an annular space between the inner member and the outer member, wherein the plurality of rolling elements are disposed;
A sensor that is disposed on the axially outer side of the annular space with respect to the sealing device, and that detects rotation of the inner member;
A wheel support bearing unit with a sensor comprising:
The sensor is
A metal case having a cylindrical portion mounted on the outer peripheral surface of the end portion of the outer member, and an inward flange portion extending radially inward from the cylindrical portion;
A resin-made holding part that is attached to the case on the radially inner side of the cylindrical part and the axially inner side of the inward flange part, and in which the detection part is embedded,
An annular portion that is externally fitted to the outer peripheral surface of the inner ring and is disposed to face the detection portion via a predetermined air gap, and an outward flange portion that extends radially outward from the annular portion. An L-shaped encoder,
With
The inward flange portion of the case and the outward flange portion of the encoder form a labyrinth having a gap narrower than the air gap,
A wheel support bearing unit with a sensor, characterized in that a drainage passage having a maximum dimension equal to or less than the air gap is formed on a butting surface of the cylindrical portion of the case and the outer member of the holding portion. .
(2) an outer member having first and second outer raceways on the inner peripheral surface;
A hub wheel having a wheel mounting flange for supporting the wheel at a portion near one end in the axial direction and having a first inner raceway surface on the outer peripheral surface and a small-diameter step formed on the hub wheel, An inner member comprising an inner ring having a second outer raceway surface on the surface;
A plurality of rolling elements arranged in a double row so as to roll freely between the first outer raceway and the first inner raceway and between the second outer raceway and the second inner raceway;
A sealing device for sealing an annular space between the inner member and the outer member, wherein the plurality of rolling elements are disposed;
A sensor that is disposed on the axially outer side of the annular space with respect to the sealing device, and that detects rotation of the inner member;
A wheel support bearing unit with a sensor comprising:
The sensor is
A metal case having a cylindrical portion mounted on the outer peripheral surface of the end portion of the outer member, and an inward flange portion extending radially inward from the cylindrical portion;
A resin-made holding part that is attached to the case on the radially inner side of the cylindrical part and the axially inner side of the inward flange part, and in which the detection part is embedded,
An encoder that rotates together with the inner member and is arranged to face the detection unit via a predetermined air gap;
With
The holding portion is integrally molded with an annular shield plate extending radially inward from the inward flange portion of the case,
The inner peripheral surface of the shield plate is in sliding contact with the inner member, or forms a labyrinth with a gap narrower than the inner member and the air gap,
A wheel support bearing unit with a sensor, characterized in that a drainage passage having a maximum dimension equal to or less than the air gap is formed on a butting surface of the cylindrical portion of the case and the outer member of the holding portion. .

  According to the wheel support bearing unit with a sensor of the present invention, the sensor includes a metal case, a resin holding portion, and an L-shaped encoder, and the holding portion is in the radial direction of the cylindrical portion. Since it is attached to the case on the inner side and the inner side in the axial direction of the inward flange portion, there is no need for a new waterproof structure for attaching a sensor as in the conventional structure, and the structure is relatively simple. In addition, the inward flange part of the case and the outward flange part of the encoder form a labyrinth with a gap narrower than the air gap, so that the waterproof and dustproof sensor of the sensor disposed on the axially outer side of the annular space with respect to the sealing device Can be improved. Furthermore, since a drainage passage having a maximum dimension equal to or less than the air gap is formed on the abutting surface of the case with the cylindrical portion and the outer member of the holding portion, it is possible to avoid the intrusion of water from the drainage passage as much as possible. The water accumulated in the space where the sensor is arranged can be discharged, and the waterproofness can be enhanced. Therefore, the durability and reliability of the wheel support bearing unit can be improved.

  According to another wheel support bearing unit with a sensor of the present invention, the sensor includes a metal case, a resin holding portion, and an encoder, and the holding portion is in the radial direction of the cylindrical portion. Since it is attached to the case on the inner side and the inner side in the axial direction of the inward flange portion, similarly, a new waterproof structure for attaching a sensor as in the conventional structure is not required, and the structure becomes relatively simple. The holding portion is integrally formed with an annular shield plate that extends radially inward from the inward flange portion of the case, and the inner peripheral surface of the shield plate is in sliding contact with the inner member, or Since the labyrinth having a narrower gap than the side member and the air gap is formed, it is possible to improve the waterproofness and dustproofness of the sensor disposed on the axially outer side of the annular space with respect to the sealing device. Furthermore, since a drainage passage having a maximum dimension equal to or less than the air gap is formed on the abutting surface of the case with the cylindrical portion and the outer member of the holding portion, it is possible to avoid the intrusion of water from the drainage passage as much as possible. The water accumulated in the space where the sensor is arranged can be discharged, and the waterproofness can be enhanced. Therefore, the durability and reliability of the wheel support bearing unit can be improved.

  Hereinafter, a sensor-equipped wheel support bearing unit according to each embodiment of the present invention will be described in detail with reference to the drawings.

(First embodiment)
The sensor-supported wheel support bearing unit 10 of the present embodiment is for a drive wheel. As shown in FIG. 1, a hub 11 that is an inner member, an outer ring 12 that is an outer member, and a plurality of rolling elements. A certain ball 13 is provided. The hub 11 includes a hollow hub wheel 15, and the hub wheel 15 is an end portion on the outboard side (an end portion on the outer side in the vehicle width direction in an assembled state in an automobile) that is a portion of the outer peripheral surface near one end in the axial direction. : The left end of FIG. 1) has a wheel mounting flange 16 extending radially outward. On the wheel mounting flange 16, a plurality of studs 17 for mounting a wheel, a brake rotor, and the like (not shown) constituting the wheel are planted on the outboard side side surface at substantially equal intervals in the circumferential direction. Furthermore, a spline groove 18 that engages with a spline shaft of a constant velocity joint (not shown) is formed on the inner peripheral surface of the hub wheel 15.

  A small-diameter step portion 19 is formed at the axial end of the hub wheel 15 on the inboard side, and an inner ring 20 is fitted on the small-diameter step portion 19. Then, the inner ring 20 is coupled and fixed to the hub wheel 15 by caulking and expanding a portion protruding from the inner end surface of the inner ring 20 of the small-diameter stepped portion 19 in the diametrically outward direction. The inner ring 20 may be fixed to the hub wheel 15 at the same time as the constant velocity joint is fixed to the hub wheel 15. A first inner ring raceway surface 21 is formed on the outer peripheral surface of the intermediate portion in the axial direction of the hub wheel 15, and a second inner ring raceway surface 22 is formed on the outer peripheral surface of the inner ring 20.

  A first outer ring raceway surface 23 corresponding to the first inner ring raceway surface 21 of the hub wheel 15 and a second outer ring raceway surface 24 corresponding to the second inner ring raceway surface 22 of the inner ring 20 are formed on the inner peripheral surface of the outer ring 12. ing. A suspension device mounting flange 25 extending radially outward is provided at the end of the outer ring 12 on the side away from the wheel mounting flange 16, and is fixed to the suspension device 26 via the flange 25. .

  A plurality of balls 13 are respectively provided in the circumferential direction via the cage 14 between the double-row first and second inner ring raceway surfaces 21 and 22 and the double-row first and second outer ring raceway surfaces 23 and 24. It is arranged so that it can roll. In the illustrated example, the balls 13 are used as the rolling elements. However, in the case of a wheel support bearing unit that is heavy, tapered rollers may be used as the rolling elements.

  A plurality of balls 13 are arranged between the inner peripheral surface of both ends of the outer ring 12 and the outer peripheral surfaces of the hub ring 15 and the inner ring 20 facing the inner peripheral surface. The outer ring 12, the hub ring 15 and the inner ring are arranged. Sealing devices 27 and 28 for sealing the annular space between them are disposed, and leakage of grease filled inside and entry of water and foreign matters from the outside are prevented.

  The inboard-side sealing device 27 is configured by sliding a sealing member 30 fixed to a core metal 29 fitted in the outer ring 12 to a slinger 31 fitted to the inner ring 20, and outboard. The side seal device 28 is configured by sliding a seal member 33 fixed to a cored bar 32 fitted in the outer ring 12 to the outer peripheral surface of the hub ring 15.

  In order to assemble the wheel support bearing unit 10 as described above to an automobile, the suspension device mounting flange 25 of the outer ring 12 is fixed to the suspension device 26, and the stud 17 and the nut are attached to the wheel mounting flange 16 of the hub wheel 15 on the rotating wheel side. The brake rotor and the wheel are fixed via a not shown. Thereby, the wheel can be rotatably supported with respect to the suspension device 26.

  Further, the wheel support bearing unit 10 includes a sensor 40 that detects the rotation of the hub 11 on the axially outer side of the annular space with respect to the inboard side sealing device 27, that is, on the inboard side of the sealing device 27.

  The sensor 40 includes a metal case 41, a resin holding part 42, a detection part 43 embedded in the holding part 42, and an L-shaped encoder 44. The case 41 includes a cylindrical portion 45 that is attached to the outer peripheral surface of the inboard side end portion of the outer ring 12, and an inward flange portion 46 that extends radially inward from the cylindrical portion 45. The holding portion 42 is insert-molded in the case 41 or fitted to the cylindrical portion 45 of the case 41, so that the holding portion 42 is attached to the case 41 on the radially inner side of the cylindrical portion 45 and the axially inner side of the inward flange portion 46. It is attached. The detection unit 43 is an IC that incorporates a magnetic detection element such as a Hall element or a magnetoresistive element (MR element) that changes its characteristics in accordance with the flow direction of magnetic flux, and a waveform shaping circuit for adjusting the output waveform of the magnetic detection element. It consists of.

  The L-shaped encoder 44 has an annular portion 47 fitted on the outer peripheral surface of the inner ring 20 that extends closer to the inboard than the outer ring 12, and extends radially outward from the annular portion 47. And an outward flange portion 48. The annular part 47 is arranged to face the detection part 43 in the radial direction via a predetermined air gap g, and changes the magnetic characteristics alternately and at equal intervals in the circumferential direction. The encoder 44 is made of a magnetic metal plate such as a mild steel plate, and a plurality of slit-like through holes 49 each having a long axial direction are formed at equal intervals in the circumferential direction at the intermediate portion in the axial direction of the annular portion 47. Thus, magnetic characteristics extending in the circumferential direction are formed alternately and at equal intervals.

  Instead of providing such a slit 45, for example, a cylindrical permanent magnet in which S poles and N poles are alternately arranged at equal intervals on the inner peripheral surface, or an internal gear-like shape on the inner peripheral surface. The annular portion 47 may be configured by externally fitting a magnetic metal member having irregularities on the cylindrical portion of the encoder 44. Further, when the encoder 44 having a permanent magnet is used, it is not necessary to incorporate a permanent magnet into the detection unit 43. However, when the encoder 44 made of a simple magnetic material is used, a magnetic flux generating source is provided on the sensor side. It is necessary to incorporate a permanent magnet. Further, the sensor 40 is not limited to an active type including the encoder 44 and the detection unit 43 including a magnetic detection element such as a Hall element. The sensor 40 is a passive type including an encoder, a magnet and an annular coil wound around it. It may be.

  The inward flange portion 46 of the case 41 and the outward flange portion 48 of the encoder 44 form a labyrinth having a gap s1 narrower than the air gap g, and seal the space S in which the detection portion 43 of the sensor 40 is disposed. Improves waterproofness and dustproofness.

  The case 41 to which the holding portion 42 is attached is fitted on the outer peripheral surface of the outer ring 12 with the axially inner side surface 50 of the holding portion 42 being abutted against the inboard side end side surface 51 of the outer ring 12. Here, radial grooves 52 are formed at a plurality of locations in the circumferential direction on the axial inner side surface 50 of the holding portion 42, and the cylindrical portion 45 of the case 41 has a radial direction of the holding portion 42. A plurality of through holes 53 are formed at positions corresponding to the grooves 52. Thereby, the cylindrical part 45 of the case 41 and the butting surfaces 50 and 51 of the holding part 42 and the outer ring 12 constitute a plurality of drainage passages 54 penetrating in the radial direction. The drainage passage 54 has a maximum dimension s2 that is less than or equal to the air gap g, and accumulates in the space S in which the detection unit 43 of the sensor 40 is disposed while avoiding the entry of water from the drainage passage 54 as much as possible. Drain water. The drainage passage 54 is preferably arranged at a position that is prevented by the housing hole 55 of the suspension device 26.

  Therefore, according to the wheel support bearing unit 10 of the present embodiment, the sensor 40 extends inward in the radial direction from the cylindrical portion 45 attached to the outer peripheral surface of the end portion of the outer ring 12 and the cylindrical portion 45. A metal case 41 having an inward flange portion 42b, a resin-made case attached to the case 41 on the radially inner side of the cylindrical portion 45 and the axially inner side of the inward flange portion 46, and in which the detector 43 is embedded. A holding part 42, an annular part 47 that is fitted on the outer peripheral surface of the inner ring 20 and is arranged to face the detection part 43 via a predetermined air gap g, and extends radially outward from the annular part 47. Since the encoder 44 having the L-shaped cross section having the outward flange portion 48 is provided, a new waterproof structure is not required when the sensor 40 is attached as in the conventional structure, and the structure is relatively simple.

  Further, the inward flange portion 46 of the case 41 and the outward flange portion 48 of the encoder 44 form a labyrinth having a gap s1 narrower than the air gap g, so that the seal device 27 is disposed outside the annular space in the axial direction. The waterproofness and dustproofness of the sensor 40 can be improved. Further, a drainage passage 54 having a maximum dimension that penetrates in the radial direction and having an air gap g or less is formed on the abutting surface 42b of the cylindrical portion 45 of the case 41 and the outer ring 12 of the holding portion 42. While avoiding water from entering the passage 54 as much as possible, it is possible to discharge the water accumulated in the space S in which the sensor 40 is disposed, thereby enhancing waterproofness. Therefore, the durability and reliability of the wheel support bearing unit 10 can be improved.

(Second Embodiment)
Next, a wheel support bearing unit with a sensor according to a second embodiment of the present invention will be described in detail with reference to FIG. The present embodiment is different from the first embodiment in the structure of the sensor, and the same parts as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted or simplified.

  The sensor 40a includes a metal case 41, a resin holding portion 42a, a detection portion 43a embedded in the holding portion 42a, and an encoder 44a. As in the first embodiment, the case 41 includes a cylindrical portion 45 attached to the outer peripheral surface of the inboard side end of the outer ring 12 and an inward flange portion 46 extending radially inward from the cylindrical portion 45. And have. The holding portion 42 a is insert-molded in the case 41 or fitted to the cylindrical portion 45 of the case 41, so that the holding portion 42 a is fitted to the case 41 on the radially inner side of the cylindrical portion 45 and the axially inner side of the inward flange portion 46. It is attached.

  The encoder 44 a is formed in an annular shape, is attached to the flange surface 60 of the slinger 31 of the sealing device 27 by insert molding, adhesion, or the like, and rotates together with the inner ring 20. The encoder 44a is opposed to the detection unit 43a in the axial direction via a predetermined air gap g, and changes the magnetic characteristics alternately and at equal intervals in the circumferential direction. In addition, the structure of the detection part 43a and the encoder 44a can be variously changed according to the detection method of a sensor similarly to 1st Embodiment.

  An annular shield plate 61 that extends radially inward from the inward flange portion 46 of the case 41 is integrally formed in the holding portion 42a. The inner peripheral surface of the shield plate 61 is in sliding contact with the outer peripheral surface of the inner ring 20 and seals the space S in which the detection portion 43a of the sensor 40a is arranged to improve waterproofness and dustproofness. Since the inner ring 20 is made of hardened steel, there is no problem even if the inner ring 20 is slightly in contact with the resin shield plate 61, and the contact is eliminated after a while due to wear of the shield plate 61, resulting in a labyrinth with substantially zero gap. The shield plate 61 may seal the space S by forming a labyrinth with a gap narrower than the inner ring 20 and the air gap g in advance, instead of being in sliding contact with the outer peripheral surface of the inner ring 20.

  Further, as in the first embodiment, the cylindrical portion 45 of the case 41 and the butting surfaces 50 and 51 of the holding portion 42a and the outer ring 12 are drained so that the maximum dimension penetrating in the radial direction is the air gap g or less. A passage 54 is formed, and water accumulated in the space S in which the detection unit 43 of the sensor 40 is disposed is discharged while avoiding entry of water from the drain passage 54 as much as possible.

  Therefore, according to the wheel support bearing unit 10 of the present embodiment, the sensor 40a extends inward in the radial direction from the cylindrical portion 45 attached to the outer peripheral surface of the end portion of the outer ring 12 and the cylindrical portion 45. A metal case 41 having an inward flange portion 46, and a resin case attached to the case 41 on the radially inner side of the tubular portion 45 and the axially inner side of the inward flange portion 46, and in which the detection portion 43 is embedded. Since it includes the holding portion 42a and the encoder 44a that rotates together with the inner ring 20 and is opposed to the detection portion 43a via a predetermined air gap g, a new waterproof structure for attaching a sensor as in the conventional structure is also provided. There is no need, and the structure is relatively simple.

  The holding portion 42a is integrally formed with an annular shield plate 61 extending radially inward from the inward flange portion 46 of the case 41, and the inner peripheral surface of the shield plate 61 is in sliding contact with the inner ring 20. Alternatively, since the labyrinth having a gap narrower than the inner ring 20 and the air gap g is formed, the waterproof and dustproof properties of the sensor 40a disposed on the outer side in the axial direction of the annular space with respect to the seal device 27 can be improved. Furthermore, a drainage passage 54 having a maximum dimension that penetrates in the radial direction and having an air gap g or less is formed on the abutting surface 42b of the cylindrical portion 45 of the case 41 and the outer ring 12 of the holding portion 42a. While avoiding water from entering the passage 54 as much as possible, it is possible to discharge the water accumulated in the space S in which the sensor 40a is arranged, and the waterproofness can be enhanced. Therefore, the durability and reliability of the wheel support bearing unit 10 can be improved.

  In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the summary of this invention, it can change suitably.

It is sectional drawing for demonstrating the wheel support bearing unit which concerns on 1st Embodiment of this invention. It is an expanded sectional view of the sensor vicinity of FIG. It is an expanded sectional view near the sensor of the bearing unit for wheel support concerning a 2nd embodiment of the present invention. It is sectional drawing for demonstrating the sensor structure of the conventional wheel support bearing unit. It is sectional drawing for demonstrating the sensor structure of the other conventional wheel support bearing unit.

Explanation of symbols

10 Wheel support bearing unit 11 Hub 12 Outer ring 13 Ball (rolling element)
15 Hub wheel 19 Small diameter step portion 20 Inner ring 21 First inner ring raceway surface 22 Second inner ring raceway surface 23 First outer ring raceway surface 24 Second outer ring raceway surface 27, 28 Sealing device 40, 40a Sensor 41 Case 42, 42a Holding portion 43 , 43a Detecting part 44, 44a Encoder 45 Cylindrical part 46 Inward flange part 47 Annular part 48 Outward flange part 54 Drain passage 61 Shield plate g Air gap

Claims (2)

An outer member having first and second outer raceway surfaces on the inner circumferential surface;
A hub wheel having a wheel mounting flange for supporting the wheel near one end in the axial direction and having a first inner raceway surface on the outer peripheral surface, and a small-diameter step formed on the hub wheel are externally fitted to the outer peripheral surface. An inner ring comprising an inner ring having a second outer raceway surface,
A plurality of rolling elements arranged in a double row so as to roll freely between the first outer raceway and the first inner raceway and between the second outer raceway and the second inner raceway;
A sealing device for sealing an annular space between the inner member and the outer member, wherein the plurality of rolling elements are disposed;
A sensor that is disposed on the axially outer side of the annular space with respect to the sealing device, and that detects rotation of the inner member;
A wheel support bearing unit with a sensor comprising:
The sensor is
A metal case having a cylindrical portion mounted on the outer peripheral surface of the end portion of the outer member, and an inward flange portion extending radially inward from the cylindrical portion;
A resin-made holding part that is attached to the case on the radially inner side of the cylindrical part and the axially inner side of the inward flange part, and in which the detection part is embedded,
An annular portion that is externally fitted to the outer peripheral surface of the inner ring and is disposed to face the detection portion via a predetermined air gap, and an outward flange portion that extends radially outward from the annular portion. An L-shaped encoder,
With
The inward flange portion of the case and the outward flange portion of the encoder form a labyrinth having a gap narrower than the air gap,
A wheel support bearing unit with a sensor, characterized in that a drainage passage having a maximum dimension equal to or less than the air gap is formed on a butting surface of the cylindrical portion of the case and the outer member of the holding portion. . An outer member having first and second outer raceway surfaces on the inner circumferential surface;
A hub wheel having a wheel mounting flange for supporting the wheel near one end in the axial direction and having a first inner raceway surface on the outer peripheral surface, and a small-diameter step formed on the hub wheel are externally fitted to the outer peripheral surface. An inner ring comprising an inner ring having a second outer raceway surface,
A plurality of rolling elements arranged in a double row so as to roll freely between the first outer raceway and the first inner raceway and between the second outer raceway and the second inner raceway;
A sealing device for sealing an annular space between the inner member and the outer member, wherein the plurality of rolling elements are disposed;
A sensor that is disposed on the axially outer side of the annular space with respect to the sealing device, and that detects rotation of the inner member;
A wheel support bearing unit with a sensor comprising:
The sensor is
A metal case having a cylindrical portion mounted on the outer peripheral surface of the end portion of the outer member, and an inward flange portion extending radially inward from the cylindrical portion;
A resin-made holding part that is attached to the case on the radially inner side of the cylindrical part and the axially inner side of the inward flange part, and in which the detection part is embedded,
An encoder that rotates together with the inner member and is arranged to face the detection unit via a predetermined air gap;
With
The holding portion is integrally molded with an annular shield plate extending radially inward from the inward flange portion of the case,
The inner peripheral surface of the shield plate is in sliding contact with the inner member, or forms a labyrinth with a gap narrower than the inner member and the air gap,
A wheel support bearing unit with a sensor, characterized in that a drainage passage having a maximum dimension equal to or less than the air gap is formed on a butting surface of the cylindrical portion of the case and the outer member of the holding portion. .

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