JP2009185921A - Wheel bearing device with rotation detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel bearing device with a rotation detector, capable of preventing wear and swelling of a magnetic encoder, increasing the strength of the construction, and reducing the size. <P>SOLUTION: The wheel bearing device includes rolling elements 5 laid between double row rolling surfaces 3, 4 of an outward member 1 and an inward member 2. Onto the outer peripheral face of the inward member 2, the magnetic encoder 21 is fitted and mounted which has an inclined face 23b inclined to the axial direction. An annular sensor holder 25 with a built-in magnetic sensor 24 is mounted on the outward member 1. The magnetic sensor 24 faces the inclined face 23b of the magnetic encoder 21 in parallel via a predetermined space. A sealing device 8 for sealing a space between the sensor holder 25 and the inward member 2 is provided at a bearing outside position beyond the magnetic encoder 21. The used magnetic encoder 21 is a plastic magnetic encoder. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wheel bearing device with a rotation detection device used in an automobile or the like equipped with an antilock brake system.

  In recent years, exports of automobile parts to BRICs countries where economic growth is remarkable are increasing. Among such automobile parts, in a wheel bearing device that rotatably supports a wheel with respect to a vehicle body, as a tire lock detection sensor of the anti-lock brake system (ABS), a magnetic encoder, and this magnetic encoder as a target In many cases, a rotation detector including a magnetic sensor for detecting the rotation of the wheel is incorporated, and the magnetic encoder is made of magnetic rubber.

  In the above-mentioned BPICs countries, automobiles are often driven on unpaved rough roads. Therefore, when a rotation detection device is incorporated in the wheel bearing device of the automobile, it has high wear resistance as its magnetic encoder. Things are required. For this reason, conventionally, measures have been taken such as to prevent wear by covering the surface of a magnetic rubber magnetic encoder manufactured by heat compression with a protective cover made of a non-magnetic material.

  However, if the surface of the magnetic encoder is covered with a protective cover made of a non-magnetic material, the gap between the surface of the magnetic encoder and the magnetic sensor arranged opposite to the surface becomes large. An encoder is required.

Therefore, as a means for solving such a problem, a wheel bearing device with a rotation detection device in which the magnetic encoder and the magnetic sensor are installed in the bearing in the axial direction is also proposed (for example, Patent Document 1). .
Japanese Patent Laying-Open No. 2005-300289

  However, when a rubber magnetic encoder is installed inside the bearing in this way, the grease, which is a lubricant, comes into contact with the magnetic encoder, and the magnetic encoder is placed in a high-temperature environment near the bearing heat generating part such as a rolling element. As a result, the magnetic encoder is likely to swell, the magnetic signal is disturbed, and accurate rotation detection cannot be performed.

  Further, since the magnetic encoder and the magnetic sensor are installed facing each other in the axial direction, the axial space of the wheel bearing device with the rotation detecting device is increased, which is an obstacle to downsizing.

  An object of the present invention is to provide a wheel bearing device with a rotation detecting device capable of preventing wear and swelling of a magnetic encoder and strengthening the structure and reducing the size of the device.

An outer member that is a fixed side member with a double row rolling surface formed on the inner periphery, an inner member that is a rotating side member that has a rolling surface that faces each of the rolling surfaces on the outer periphery, and these facing members And a double row rolling element interposed between the rolling surfaces, wherein the wheel bearing device supports the wheel rotatably with respect to the vehicle body, and is fitted to the outer peripheral surface near the end of the inner member. A magnetic encoder that is attached to the outer member and has a slanted surface that is inclined with respect to the axial direction so that the outer peripheral surface faces the end of the inner member, and a slinger that is provided on the outer periphery, and is magnetically attached to the outer member. An annular sensor holder in which a sensor is incorporated and this magnetic sensor faces the inclined surface of the magnetic encoder in parallel with a gap, and the sensor holder and the inner member at positions outside the bearing relative to the magnetic encoder A sealing device for sealing the space between The serial magnetic encoder, magnets to be detected portion is characterized in that the plastic magnetic encoder is Purachikku magnet.
According to this configuration, the detected surface of the magnetic encoder is an outwardly inclined surface, the sensor holder containing the magnetic sensor facing the inclined surface is attached to the outer member, and the sealing device is disposed at a position outside the bearing relative to the magnetic encoder. Since it is provided, it is possible to prevent the magnetic encoder from being worn by foreign matters from the outside. In particular, since a plastic magnetic encoder is used as the magnetic encoder, the magnet portion can be prevented from coming into contact with the grease as the lubricant and swelling. As a result, wear and swelling of the magnetic encoder can be prevented and accurate rotation detection can be performed.
In addition, since the magnetic encoder has an inclined surface to be detected, the cross-sectional outline can be made triangular and the structure can be strengthened.
In addition, since the detected surface of the magnetic encoder is an inclined surface, the magnetic encoder is arranged at the same axial position as the sensor holder. Therefore, the wheel bearing device with a rotation detecting device is provided by the axial length of the magnetic encoder. The axial length can be shortened and the device can be made compact.

In the present invention, in the plastic magnetic encoder, the plastic magnet is a multipolar magnet in which magnetic poles are arranged in a circumferential direction. The multipolar magnet includes magnetic powder and a thermoplastic resin, and the magnetic powder-containing thermoplastic The melt viscosity of the resin may be 30 Pa · s or more and 1500 Pa · s or less.
When the melt viscosity is less than 30 Pa · s, the magnetic powder-containing thermoplastic resin, which is a material for the plastic multipolar magnet, generates a large amount of burrs during injection molding, making it difficult to mold appropriately. If the melt viscosity of the thermoplastic resin is greater than 1500 Pa · s, it will be difficult to knead the magnetic powder into the thermoplastic resin. In particular, when the proportion of the magnetic powder is increased, the kneading failure becomes remarkable. Therefore, by setting the melt viscosity of the magnetic powder-containing thermoplastic resin to 30 Pa · s or more and 1500 Pa · s or less, a plastic magnetic encoder with good productivity can be obtained. Further, the productivity improvement of the plastic magnetic encoder leads to the productivity improvement of the wheel bearing device with the rotation detection device.

In the present invention, the thermoplastic resin may include one or more compounds selected from the group consisting of polyamide 12, polyamide 612, polyamide 11, and polyphenylene sulfide.
These thermoplastic resins have very low swelling (less than 10%) even when immersed in grease used as a lubricant for bearings at high temperatures, so they have poor water absorption, condensation at low temperatures, salt water and muddy water. It is resistant to deterioration even in an environment with a lot of moisture such as rain water, and is particularly effective as a material for a plastic magnetic encoder incorporated in a wheel bearing device.

  In the present invention, the magnetic powder may be a ferrite-based magnetic powder. Since the ferrite-based magnetic powder is difficult to oxidize, the corrosion resistance of the plus-chip magnetic encoder can be improved.

  In the present invention, the magnetic powder may be anisotropic ferrite magnetic powder.

  In this invention, the plastic magnet of the plastic magnetic encoder may be an injection molded product.

  When the plastic magnet is an injection-molded product, the plastic magnet may be one that has been subjected to magnetic field molding in injection molding. By forming the magnetic field in this way, a plastic magnetic encoder with a higher magnetic flux density can be obtained.

In this invention, the plastic magnetic encoder may be a single annular plastic magnet having an inner peripheral surface that is press-fitted into the outer peripheral surface of the inner member and is fixed, and an outer peripheral surface that is the inclined surface. .
If the plastic magnetic encoder is constituted by a single plastic magnet having no slinger as described above, the cost of the plastic magnetic encoder can be reduced.

  In the present invention, the plastic magnetic encoder includes a cylindrical portion that is press-fitted and fixed to the outer peripheral surface of the inner member, and a slinger having an L-shaped cross section including a standing plate portion that rises from one end portion of the cylindrical portion, and the slinger And a plastic magnet having an outer peripheral surface that is integrally formed over the cylindrical portion and the upright plate portion and is formed as the inclined surface.

  In the present invention, the plastic magnetic encoder having the slinger may be an insert-molded product in which the plastic magnet is integrally molded by injecting a magnetic powder-containing thermoplastic resin into a mold in which the slinger is disposed.

  In the present invention, the slinger may be made of a magnetic material. By using a magnetic material as the material of the slinger, the magnetic force of the plastic magnetic encoder can be increased compared to the case of using a non-magnetic material.

  The wheel bearing device with a rotation detecting device according to the present invention is fitted to and attached to the outer peripheral surface in the vicinity of the end of the inner member, and the axial direction is such that the outer peripheral surface faces the end of the inner member. A magnetic encoder having an inclined surface and a slinger provided on the outer periphery are fitted to the outer member in a fitted state, and a magnetic sensor is incorporated, and the magnetic sensor is inserted into the inclined surface of the magnetic encoder via a gap. An annular sensor holder facing each other in parallel, and a sealing device that seals a space between the sensor holder and the inner member at a position outside the bearing at a position outside the magnetic encoder, Since the plastic magnetic encoder is a plastic magnet, the wear and swelling of the magnetic encoder can be prevented and the structure can be strengthened, and the apparatus can be made compact.

  An embodiment of the present invention will be described with reference to FIGS. The wheel bearing device with a rotation detection device of this embodiment is a double row angular contact ball bearing type classified as a third generation type, and is an inner ring rotation type and a drive wheel support type. In this specification, the side closer to the outer side in the vehicle width direction of the vehicle when attached to the vehicle is referred to as the outboard side, and the side closer to the center of the vehicle is referred to as the inboard side.

  As shown in the sectional view of FIG. 1, the wheel bearing device in the wheel bearing device with the rotation detecting device includes an outer member 1 in which a double row rolling surface 3 is formed on the inner periphery, and each of these rolling surfaces. 3, an inner member 2 formed on the outer periphery with a rolling surface 4 facing the outer periphery 3, and a double row rolling element 5 interposed between the outer member 1 and the rolling surfaces 3, 4 of the inner member 2. The The rolling elements 5 are formed of balls and are held by the cage 6 for each row. The rolling surfaces 3 and 4 have a circular arc shape in cross section, and the rolling surfaces 3 and 4 are formed so that the contact angles are aligned with the back surface. The end of the bearing space between the outer member 1 and the inner member 2 is sealed by a sealing device 7.

The outer member 1 is a fixed side member, and has a flange 1a for mounting a vehicle body attached to a knuckle 60 in a suspension device (not shown) of the vehicle body on the outer periphery, and the whole is an integral part. . Bolt holes 14 for mounting the vehicle body are provided at a plurality of locations in the circumferential direction of the flange 1a, and knuckle bolts 61 inserted from the inboard side into the bolt insertion holes 60a of the knuckle 60 are screwed into the bolt holes 14 of the flange 1a. By doing so, the flange 1a is bolted to the knuckle 60.
The inner member 2 is a rotating side member, and includes a hub wheel 9 having a hub flange 9a for wheel mounting, and an inner ring 10 fitted to the outer periphery of the end portion on the inboard side of the shaft portion 9b of the hub wheel 9. And become. The hub wheel 9 and the inner ring 10 are formed with the rolling surfaces 4 of the respective rows. An inner ring fitting surface 12 having a small diameter with a step is provided on the outer periphery of the inboard side end of the hub wheel 9, and the inner ring 10 is fitted to the inner ring fitting surface 12. A through hole 11 is provided at the center of the hub wheel 9. The stem portion 63a of the outer ring 63 of the constant velocity joint 62 is inserted into the through-hole 11, and the inner member 2 is sandwiched between the stepped surface around the proximal end of the stem portion 63a and the nut 64 that is screwed to the distal end. Thus, the wheel bearing device and the constant velocity joint 62 are connected. The hub flange 9a is provided with press-fit holes 16 for hub bolts 15 at a plurality of locations in the circumferential direction. In the vicinity of the base portion of the hub flange 9a of the hub wheel 9, a cylindrical pilot portion 13 for guiding a brake rotor and a wheel (not shown) protrudes toward the outboard side. The pilot rotor 13 guides the hub flange 9 a so that the brake rotor and the wheel are overlapped with each other and fixed with the hub bolt 15.

  FIG. 2 is an enlarged cross-sectional view of part A in FIG. A plastic magnetic encoder 21 is fitted and attached to the inboard side end of the outer peripheral surface of the inner member 2. An annular sensor holder 25 containing a magnetic sensor 24 for detecting the magnetic flux of the plastic magnetic encoder 21 is attached to the inboard side end of the outer member 1. The plastic magnetic encoder 21 and the magnetic sensor 24 constitute a rotation detection device 20 that detects the rotation of the inner member 2 integral with the plastic magnetic encoder 21, that is, the rotation of the wheel.

The plastic magnetic encoder 21 includes an inner peripheral surface 23a that is press-fitted and fixed to the outer peripheral surface of the inner member 2 (here, the outer peripheral surface of the inner ring 10), and an outer side with respect to the axial direction so that the inner diameter of the bearing is large. The annular plastic multipolar magnet 23 having an inclined surface 23b which is an outer peripheral surface inclined in the direction is a single body. The inclined surface 23b becomes a detected surface. The plastic multipolar magnet 23 has a sealing device fitting protrusion 23c that fits on an outer diameter surface of a sealing plate 31 of the sealing device 8 described later at the outer end in the axial direction.
The sensor holder 25 is attached to the outer member 1 so that the magnetic sensor 24 faces the inclined surface 23b of the plastic magnetic encoder 21 (plastic multipolar magnet 23) in parallel with a predetermined gap.

  As shown in FIG. 3, the plastic multipolar magnet 23 is an annular member magnetized in multiple poles so that the magnetic poles N and S are alternately arranged in the circumferential direction, and magnetic powder and thermoplastic as a binder. It is an injection-molded product containing resin. The magnetic poles N and S are formed to have a predetermined pitch p in the pitch circle diameter PCD.

If the melt viscosity of the magnetic powder-containing thermoplastic resin, which is the material of the plastic multipolar magnet 23, is less than 30 Pa · s, a large amount of burrs are generated during injection molding, making it difficult to mold appropriately. If the melt viscosity of the thermoplastic resin is greater than 1500 Pa · s, it will be difficult to knead the magnetic powder into the thermoplastic resin. In particular, when the ratio of the magnetic powder is increased, the kneading failure becomes remarkable. Thus, in this embodiment, the melt viscosity of the magnetic powder-containing thermoplastic resin is 30 Pa · s or more and 1500 Pa · s or less. Thereby, the plastic magnetic encoder 21 with good productivity can be obtained. Moreover, it leads also to the productivity improvement of the wheel bearing apparatus with a rotation detection apparatus.
The melt viscosity of the thermoplastic resin in this case is a capillograph (manufactured by Toyo Seiki Co., Ltd.), using a capillary with a diameter of 1 mmφ and a land length of 10 mm, a shear rate of 100 (l / s), and a melting point of the thermoplastic resin. The result measured at the temperature of +50 degreeC is shown.

  In this case, the thermoplastic resin includes polyamide 12, polyamide 612, polyamide 11, and poniphenylene sulfide which have a very small amount of swelling (less than 10%) even when immersed in grease used as a lubricant in a bearing at a high temperature. Preferably, it comprises one or more compounds selected from the group of Since such a thermoplastic resin has poor water absorption, the thermoplastic resin is resistant to deterioration even in a high moisture environment such as dew condensation at low temperatures, salt water, muddy water, rainwater, etc. It is particularly effective as a material.

  Barium-based or strontium-based ferrite powder is used as the magnetic powder that is a material of the plastic multipolar magnet 23. In the case of a ferrite magnetic powder, it may be an isotropic ferrite magnetic powder or an anisotropic ferrite magnetic powder. Since such ferrite-based magnetic powder is difficult to oxidize, the corrosion resistance of the plastic magnetic encoder 21 can be improved. In addition, when the magnetic force is insufficient with only ferrite magnetic powder, rare earth magnetic powder such as samarium iron magnetic powder or neodymium iron magnetic powder may be mixed with ferrite magnetic powder and used.

  The plastic magnetic encoder 21 is manufactured by the following process. First, the magnetic powder and the molten thermoplastic resin are kneaded using a twin screw extruder or a kneader, and the magnetic powder is appropriately dispersed in the thermoplastic resin. Then, injection molding etc. are performed so that it may become a shape of a multipolar magnet, and a desired molded object is obtained. The molded product thus obtained is magnetized into multiple poles using a magnetizing yoke to form a magnetic pole. At the time of the injection molding, it is preferable to form a magnetic field while applying a vertical magnetic field of 80000 Oe or more to the magnetic encoder magnetized surface and to orient the contained magnetic powder. By forming the magnetic field in this way, the plastic magnetic encoder 21 having a larger magnetic flux density can be obtained.

  The annular sensor holder 25 includes an annular cored bar 26 and a resin sensor holder 27 that incorporates a magnetic sensor 24 and is coupled to the cored bar 26. The sensor holding body 27 protrudes from the inner bearing end in the axial direction to the inner peripheral surface, and is provided with a sensor embedded protrusion 27a. In the sensor embedded protrusion 27a, the corner between the tip surface and the bearing inner surface is an inclined surface parallel to the inclined surface 23b of the magnetic encoder 21, and the magnetic sensor 24 is built in along the inclined surface. Yes. The sensor embedding protrusion 27a may be annular or may be locally provided in a part of the circumferential direction. The core metal 26 includes an outer diameter cylindrical portion 26a that is press-fitted and attached to the outer peripheral surface of the outer member 1, a flange portion 26b that extends from the inboard side end of the outer diameter cylindrical portion 26a toward the inner diameter side, and the flange portion 26b. The inner diameter cylindrical portion 26c extends in the axial direction from the inner diameter side end of the inner diameter. The cored bar 26 is formed by pressing a corrosion resistant stainless steel plate or the like. Perforations 28 are formed at a plurality of locations in the circumferential direction of the inner diameter cylindrical portion 26c in the cored bar 26, and a resin sensor holding body 27 is integrally molded at a portion extending from the inner diameter cylindrical portion 26c to the flange portion 26b. In a state where the outer diameter cylindrical portion 26a of the metal core 26 is press-fitted into the outer peripheral surface of the outer member 1, and the flange portion 26b is brought into close contact with the inboard side end surface of the outer member 1, the sensor holder 25 is moved to the outer member. 1 is fixed to the inboard side end.

The space between the inner periphery of the sensor holder 25 and the outer periphery of the inner member 2 is sealed by a sealing device 8 installed at a position outside the bearing relative to the plastic magnetic encoder 21. The sealing device 8 includes annular first and second seal plates 31 and 32 attached to the outer peripheral surface of the inner member 2 and the inner peripheral surface of the sensor holder 25, respectively.
The first seal plate 31 includes a cylindrical portion 31a that is press-fitted and attached to the outer peripheral surface of the inner member 2, and a cross-section L that includes a vertical plate portion 31b that extends from the inboard side end of the cylindrical portion 31a to the outer diameter side. It is formed in a letter shape. The first seal plate 31 is formed by pressing an austenitic stainless steel plate or a cold-rolled steel plate that has been rust-proofed.
The second seal plate 32 includes a cylindrical portion 32a that is press-fitted and attached to the inboard side of the inner peripheral surface of the sensor holder 25, and a standing plate portion 32b that extends from the outboard side end of the cylindrical portion 32a to the inner diameter side. The cross section is formed in an inverted L shape. The second seal plate 32 has an upright plate portion 32b positioned on the outboard side of the upright plate portion 31b of the first seal plate 31, and is axially aligned with the upright plate portion 31b of the first seal plate 31. It arrange | positions so that it may face. A seal member 33 having a side lip 33a, a grease lip 33b, and an intermediate lip 33c is vulcanized and bonded to the second seal plate 32. The seal member 33 is made of an elastic member such as rubber. The side lip 33 a is in sliding contact with the standing plate portion 31 b of the first seal plate 31, and the grease lip 33 b and the intermediate lip 33 c are in sliding contact with the cylindrical portion 31 a of the first seal plate 31. The tip of the upright plate portion 31b of the first seal plate 31 is opposed to the cylindrical portion 32a of the second seal plate 32 via a slight radial gap to constitute a labyrinth seal. The sealing device 8 seals the inboard side end in the bearing space between the outer member 1 and the inner member 2.

  According to the wheel bearing device with a rotation detection device having the above-described configuration, the plastic magnetic encoder 21 integrated with the inner member 2 rotates as the wheel rotates. At this time, the magnetic sensor 24 facing the inclined surface 23b, which is a magnetized surface of the plastic magnetic encoder 21 (plastic multipolar magnet 23), in parallel through a predetermined gap is used as the magnetic force of the magnetic poles N and S of the plastic magnetic encoder 21. Read changes. Thereby, the rotation detection apparatus 20 comprised by the plastic magnetic encoder 21 and the magnetic sensor 24 can detect rotation of a wheel.

  Further, in this wheel bearing device with a rotation detection device, a sensor holder 25 including a magnetic sensor 24 that constitutes the rotation detection device 20 with a plastic magnetic encoder 21 fitted and attached to the outer peripheral surface of the inner member 2 is provided. The magnetic sensor 24 is attached to the outer member 1 so as to face the inclined surface 23b of the plastic magnetic encoder 21, and is positioned between the sensor holder 25 and the inner member 2 at a position outside the bearing relative to the plastic magnetic encoder 21. Since the sealing device 8 for sealing the space is provided, it is possible to prevent the plastic magnetic encoder 21 from being worn by foreign matters or the like from the outside.

  In particular, since the plastic magnetic encoder 21 (plastic multipolar magnet 23) is used as the magnetic encoder, the magnetic encoder can be prevented from coming into contact with the grease, which is a lubricant, and swelled, and accurate rotation detection is possible.

  In addition, since the cross section of the plastic magnetic encoder 21 can be triangular, the structure of the plastic magnetic encoder 21 can be strengthened.

  Further, since the plastic magnetic encoder 21 is disposed at the same axial position as the sensor holder 25, the axial length of the wheel bearing device with the rotation detecting device can be shortened by the axial length of the plastic magnetic encoder 21, The device can be made compact.

  FIG. 4 shows another embodiment of the present invention. In this embodiment, in the wheel bearing device with a rotation detecting device of the embodiment of FIGS. 1 to 3, a plastic magnetic encoder 21 composed of a single plastic multipole magnet 23 is replaced by an annular slinger 22 and a plastic multipole magnet 23. This is replaced with a plastic magnetic encoder 21A made of a composite of the above.

  The slinger 22 is a cylindrical portion 22a that is press-fitted and fixed to the outer peripheral surface of the inner member 2 (here, the outer peripheral surface of the inner ring 10), and a standing plate portion that rises from the inner end of the cylindrical portion 22a to the outer diameter side. It is a cored bar having an annular shape and an L-shaped cross section composed of 22b. The plastic multipolar magnet 23 is integrally formed over the cylindrical portion 22a and the upright plate portion 22b of the slinger 22 and has the slope portion 23b which is an outer peripheral surface. The slinger 22 is made of a magnetic steel plate. Thus, by using a magnetic material as the material of the slinger 22, the magnetic force of the plastic magnetic encoder 21A can be increased as compared with the case of using a non-magnetic material.

  The plastic magnetic encoder 21A is manufactured by the following process. First, the magnetic powder and the molten thermoplastic resin are kneaded using a twin screw extruder or a kneader, and the magnetic powder is appropriately dispersed in the thermoplastic resin. Thereafter, a thermoplastic resin containing magnetic powder is injected into the mold in which the slinger 22 is disposed, and the plastic multipole magnet 23 is integrally formed with the slinger 22 to obtain a desired plastic magnetic encoder 21A. The insert molded product of the plastic magnetic encoder 21A thus obtained is magnetized into multiple poles using a magnetizing yoke, whereby the magnetic poles of the plastic multipole magnet 23 are formed. Also in this case, at the time of the injection molding, it is preferable to form a magnetic field while applying a vertical magnetic field of 80000 Oe or more to the inclined surface 23b which is a magnetized surface, and to magnetically orient the contained magnetic powder. Other configurations are the same as those of the embodiment shown in FIGS. 1 to 3, and the description thereof is omitted here.

It is sectional drawing of the bearing apparatus for wheels with a rotation detection apparatus concerning one Embodiment of this invention. It is an expanded sectional view of the A section in FIG. It is explanatory drawing of the magnetic pole which looked at the plastic magnetic encoder from the front. It is a partial expanded sectional view of the bearing device for wheels with a rotation detector concerning other embodiments of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Outer member 2 ... Inner member 3, 4 ... Rolling surface 5 ... Rolling body 8 ... Sealing device 20 ... Rotation detection device 21, 21A ... Plastic magnetic encoder 22 ... Slinger 22a ... Cylindrical part 22b ... Standing plate part 23 ... Plus-chip multipole magnet 23a ... Inner peripheral surface 23b ... Inclined surface 24 ... Magnetic sensor 25 ... Sensor holder

Claims (11)

An outer member that is a fixed side member with a double row rolling surface formed on the inner periphery, an inner member that is a rotating side member that has a rolling surface that faces each of the rolling surfaces on the outer periphery, and these facing members A wheel bearing device for supporting a wheel rotatably with respect to a vehicle body, comprising:
A magnetic encoder that is fitted and attached to the outer peripheral surface near the end of the inner member and is inclined with respect to the axial direction so that the outer peripheral surface faces the end of the inner member, and An annular sensor holder that is attached to the outer member in a fitted state with a cored bar having a built-in magnetic sensor and that faces the inclined surface of the magnetic encoder in parallel via a gap; and A sealing device that seals a space between the sensor holder and the inner member at a position outside the bearing relative to the magnetic encoder, and the magnetic encoder is a plastic magnetic encoder in which a magnet to be detected is a plastic magnet; A wheel bearing device with a rotation detecting device, characterized in that   2. The plastic magnetic encoder according to claim 1, wherein the magnetic encoder is a multipolar magnet in which magnetic poles are arranged in a circumferential direction, the multipolar magnet including magnetic powder and a thermoplastic resin, and the magnetic powder-containing thermoplastic. A wheel bearing device with a rotation detector, wherein the melt viscosity of the resin is 30 Pa · s to 1500 Pa · s.   3. The wheel bearing device with a rotation detecting device according to claim 2, wherein the thermoplastic resin includes one or more compounds selected from the group consisting of polyamide 12, polyamide 612, polyamide 11, and polyphenylene sulfide.   4. The wheel bearing device with a rotation detecting device according to claim 2, wherein the magnetic powder is a ferrite-based magnetic powder.   5. The wheel bearing device with a rotation detecting device according to claim 4, wherein the magnetic powder is anisotropic ferrite magnetic powder.   The wheel bearing device with a rotation detecting device according to any one of claims 1 to 5, wherein the plastic magnet of the plastic magnetic encoder is an injection molded product.   7. The wheel bearing device with a rotation detecting device according to claim 6, wherein the plastic magnet of the plastic magnetic encoder is formed by magnetic field molding in injection molding.   The plastic magnetic encoder according to claim 1, wherein the plastic magnetic encoder has an annular shape having an inner peripheral surface that is press-fitted and fixed to an outer peripheral surface of the inner member and an outer peripheral surface that is the inclined surface. Wheel bearing device with rotation detector, which is a single plastic magnet.   8. The plastic magnetic encoder according to claim 1, wherein the plastic magnetic encoder includes a cylindrical portion that is press-fitted and fixed to the outer peripheral surface of the inner member, and a standing plate portion that rises from one end portion of the cylindrical portion. A wheel bearing device with a rotation detecting device comprising an annular slinger having an L-shaped cross section and a plastic magnet having an outer peripheral surface formed integrally with the cylindrical portion and the standing plate portion of the slinger and having an inclined surface.   10. The wheel bearing device with a rotation detection device according to claim 9, wherein the plastic magnetic encoder is an insert-molded product in which the plastic magnet is integrally molded by injecting a magnetic powder-containing thermoplastic resin into a mold in which the slinger is disposed. .   11. The wheel bearing device with a rotation detector according to claim 9, wherein the slinger is made of a magnetic material.

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