JP5274041B2 - 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 accurately detecting rotation while preventing the wear and swelling of a magnetic encoder, and of achieving improved assembling efficiency and reduced 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 axial type magnetic encoder 21 is fitted and mounted. 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 magnetic encoder 21 via a predetermined space at a bearing inside position beyond the magnetic encoder 21 in the axial direction. 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 having a plastic multipolar magnet 23. <P>COPYRIGHT: (C)2009,JPO&amp;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.

The B R ICs countries mentioned above, since in many cases the vehicle is operated in rough road unpaved, when the rotation detection device is incorporated in a wheel support bearing assembly of the vehicle, the wear resistance as a magnetic encoder A high one is 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 inside the bearing has also been 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.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a wheel bearing device with a rotation detection device that can prevent wear and swelling of a magnetic encoder, accurately detect rotation, and improve assembly and make it compact.

In the wheel bearing device with a rotation detecting device of the present invention, a double row rolling surface is formed on the inner periphery and an outer member serving as a fixed member and a rolling surface facing each of the rolling surfaces are formed on the outer periphery. An inner member serving as a rotation side member, and a double row rolling element interposed between the opposing rolling surfaces, and is fitted and attached to the outer peripheral surface near the end of the inner member. A magnetic encoder facing in the direction and a metal bar attached to the outer member with a metal core on the outer periphery, and a magnetic sensor is built in. The magnetic sensor is spaced from the magnetic encoder at a position inside the bearing in the axial direction than the magnetic encoder. A ring-shaped sensor holder that faces in the axial direction via a sealing device that seals a space between the sensor holder and the inner member at a position outside the bearing in the axial direction with respect to the magnetic encoder, The magnetic encoder is a magnet to be detected A plastic magnetic encoder is Purachikku magnet, wherein the sensor holder, and the core metal, the built-in magnetic sensor becomes in a resin sensor holder ring coupled to the metal core, the outer member is The inboard side end surface is formed in a shape recessed toward the outboard side from the inboard side end surface of the inner member, and the sensor holding body is provided at a recessed portion of the outer member, and the cored bar Is an outer diameter cylindrical portion that is press-fitted and attached to the outer peripheral surface of the outer member, a flange portion that extends from the inboard side end of the outer diameter cylindrical portion to the inner diameter side, and an axial direction from the inner diameter side end of the flange portion The sensor holder is fixed to the inboard side end of the outer member, and the sensor holder is fixed to the inboard side end surface of the outer member. Its axial bearing A sensor-embedded protrusion that protrudes inward from a hole formed in the inner diameter cylindrical portion of the metal core at a side end and incorporates the magnetic sensor, and is disposed at a portion extending from the inner diameter cylindrical portion to the flange portion. The resin sensor holding body is integrally molded .
According to this configuration, the sensor holder incorporating the magnetic sensor is attached to the outer member so as to face the magnetic encoder in the axial direction at a position inside the bearing relative to the magnetic encoder attached to the inner member. A sealing device is provided for sealing a space between the sensor holder and the inner member at a position outside the bearing. For this reason, 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 is possible.
In addition, since the magnetic encoder and the sealing device can be assembled together after attaching the sensor holder to the outer member in the assembly of the rotation detection device into the wheel bearing device, the assembly of the wheel bearing device with the rotation detection device is possible. Improves.
In addition, since the magnetic encoder is arranged at the same axial position as the sensor holder, the axial length of the wheel bearing device with the rotation detecting device can be shortened by the axial length of the magnetic encoder, and the device can be made compact. It becomes possible.

In the present invention, the plastic magnetic encoder is a multi-pole magnet that flop Rasuchi click magnets arranged magnetic poles in a circumferential direction, the multi-pole magnet comprises a magnetic powder and a thermoplastic resin, the magnetic powder-containing The melt viscosity of the thermoplastic resin may be 30 Pa · s or more and 1500 Pa · s or less.
If the melt viscosity of the magnetic powder-containing thermoplastic resin, which is the material of the plastic magnet, 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. 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. In addition, the improvement in the productivity of the plastic magnetic encoder also leads to the improvement in the productivity of the wheel bearing device with the rotation detection device.

The thermoplastic resin of the flop Rasuchi click magnet, polyamide 12, polyamide 612, polyamide 11, may include one or more compounds selected from the group of 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 ferritic magnetic powder is hard to oxidize, thereby improving the corrosion resistance of the plastic magnetic encoder.

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

In the present invention, the flop Rasuchi click magnet of the plastic magnetic encoder may be injection-molded article.

If the flop Rasuchi click magnet is an injection molded article, the flop Rasuchi click magnet may be obtained by magnetic field formed in an injection molding. By forming the magnetic field in this way, a plastic magnetic encoder with a higher magnetic flux density can be obtained.

In the present invention, the plastic magnetic encoder is an annular plastic magnet having an L-shaped cross section comprising a cylindrical portion press-fitted and fixed to the outer peripheral surface of the inner member, and a standing plate portion rising from one end portion of the cylindrical portion. It may be a simple substance.
Thus, if a plastic magnetic encoder is composed of a single plastic multipole magnet having no slinger, the cost of the plastic magnetic encoder can be reduced. Also this flop Rasuchi click magnet, for fitting the inner member with the cylindrical portion, can be performed rigid mounting.

  In this invention, the plastic magnetic encoder includes an annular slinger having an L-shaped cross section comprising a cylindrical portion that is press-fitted and fixed to the outer peripheral surface of the inner member, and an upright plate portion that rises from one end of the cylindrical portion. The plastic magnet may be integrally formed with the standing plate portion of the slinger.

  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.

In the wheel bearing device with a rotation detecting device of the present invention, a double row rolling surface is formed on the inner periphery and an outer member serving as a fixed member and a rolling surface facing each of the rolling surfaces are formed on the outer periphery. A wheel bearing device that includes an inner member that is a rotating side member and a double-row rolling element interposed between the opposing rolling surfaces, and that supports the wheel rotatably with respect to the vehicle body. A magnetic encoder that fits and is attached to the outer peripheral surface near the end of the member and faces in the axial direction, and a magnetic sensor that is attached to the outer member with a metal core on the outer periphery and is built in. Is a ring-shaped sensor holder facing the magnetic encoder in the axial direction through a gap at a position inside the bearing in the axial direction with respect to the magnetic encoder, and the sensor holder and the inside at a position outside the bearing in the axial direction with respect to the magnetic encoder. Seal the space between the side members And a sealing device, the magnetic encoder, magnets to be detected portion is a plastic magnetic encoder is Purachikku magnet, wherein the sensor holder, and the core metal, coupled to the metal core incorporates the magnetic sensor The outer member is formed in a shape in which the end surface on the inboard side is recessed toward the outboard side from the end surface on the inboard side of the inner member. The sensor holding body is provided in a recessed portion of the member, and the cored bar is attached to the outer peripheral surface of the outer member by being press-fitted and attached from an inboard side end of the outer diameter cylindrical portion. The sensor holder is composed of a flange extending toward the inner diameter side and an inner diameter cylindrical portion extending in the axial direction from the inner diameter side end of the flange, with the flange closely contacting the inboard side end surface of the outer member. Of the outer member The sensor holding body is fixed to the board side end, and the sensor holding body is embedded in the sensor that protrudes inward from the hole formed in the inner diameter cylindrical portion of the cored bar at the inner end of the axial bearing. It has a projection, because the resin of the sensor holder from the inside diameter cylindrical portion at a portion across the flange portion is integrally molded, to prevent wear or swelling of the magnetic encoder enables accurate rotation detection In addition, the assemblability can be improved and the size can be reduced.

  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 in the flange 1a at a plurality of locations in the circumferential direction, 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. On the other hand, an annular sensor holder 25 incorporating 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 is an axial type in which the surface to be detected faces in the axial direction, and a cylindrical portion 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 this cylinder The unit 23a is a single unit of an annular plastic multipolar magnet 23 having an L-shaped cross section composed of an upright plate portion 23b that rises from the outer end of the bearing in the axial direction to the outer diameter side. In the plastic magnetic encoder 21, an annular sealing device fitting protrusion 23 c is provided in the vicinity of the base end of the outward surface of the standing plate portion 23 b, and is fitted to the outer peripheral surface of the end portion of the sealing plate 32 described later in the sealing device 8. Match.
The sensor holder 25 is arranged so that the magnetic sensor 24 faces the upright plate portion 23b of the plastic magnetic encoder 21 in the axial direction at a position inside the bearing relative to the upright plate portion 23b of the plastic magnetic encoder 21 through a predetermined gap. It is attached to the direction member 1.

  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.

When the melt viscosity is less than 30 Pa · s, the magnetic powder-containing thermoplastic resin that is the material of the plastic multipolar magnet 23 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 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.
In this case, the melt viscosity of the thermoplastic resin 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 these thermoplastic resins have poor water absorption, they are resistant to deterioration even under high moisture conditions such as dew condensation at low temperatures, salt water, muddy water, rain water, etc., and the material of the plastic magnetic encoder 21 incorporated in the wheel bearing device. As particularly effective.

  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 an annular resin sensor holder 27 that incorporates the magnetic sensor 24 and is coupled to the cored bar 26. The sensor holding body 27 protrudes from the inner end of the bearing in the axial direction to the inner peripheral surface and is provided with a sensor embedded protrusion 27a. The magnetic sensor 24 is built in the sensor embedded protrusion 27a. The sensor embedding protrusion 27a may be annular or provided locally at 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 plastic magnetic encoder 21 (plastic multipolar magnet 23) in the axial direction through a predetermined gap reads the change in magnetic force of the magnetic poles N and S of the plastic magnetic encoder 21. 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 incorporating a magnetic sensor 24 that constitutes the rotation detection device 20 with an axial plastic magnetic encoder 21 fitted and attached to the outer peripheral surface of the inner member 2. the holder 25, in the magnetic sensor 24 is fitted to the outer member 1 so as to face to the plastic magnetic encoder 21 and axially bearing a side position than the plastic magnetic encoder 21, the bearing outer position than the plastic magnetic encoder 21 Since the sealing device 8 that seals the space between the sensor holder 25 and the inner member 2 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.

Further, when the rotation detection device 20 is incorporated in the wheel bearing device, the plastic magnetic encoder 21 and the sealing device 8 are positioned on the outer side in the axial direction with respect to the built-in portion of the magnetic sensor 24 of the sensor holder 25. After attaching the sensor holder 25 to 1, the plastic magnetic encoder 21 and the sealing device 8 can be assembled together. That is, contrary to the above, when the magnetic encoder is located inside the magnetic sensor 24 in the axial direction, the magnetic encoder, the sensor holder, and the sealing device need to be incorporated for incorporation, which is a three-step assembly operation. but in this embodiment, when the embedded sensor holder 25, requires only two steps and the incorporation of the polymer product of the magnetic encoder 21 and the sealing device 8. Therefore, the assemblability of the wheel bearing device with a rotation detection device is improved. When the plastic magnetic encoder 21 has the sealing device fitting protrusion 23c as described above, the work of assembling the magnetic encoder 21 and the sealing device 8 together becomes easier.

  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. This embodiment is a composite of a slinger 22 and a plastic multipole magnet 23 in a plastic magnetic encoder 21 composed of a single unit of a plastic multipole magnet 23 in the wheel bearing device with a rotation detecting device of the embodiment of FIGS. This is replaced with a plastic magnetic encoder 21A.

  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 outward from the bearing outer end of the cylindrical portion 22a. This is a core bar having an L-shaped cross section consisting of 22b. The plastic multi-pole magnet 23 is integrally formed on the inward surface of the standing plate portion 22b of the slinger 22, that is, on one side facing the magnetic sensor 24 built in the sensor holder 25. An end portion on the outer diameter side of the plastic multipolar magnet 23 is formed so as to hold the standing plate portion 22 b of the slinger 22 and is integrally held by the slinger 22. 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 21 </ b> A can be increased compared to the case of using a nonmagnetic 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. In this case as well, 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 at the time of the injection molding and to 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 ... plastic multipolar magnet 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 which is fitted and attached to the outer peripheral surface near the end of the inner member and faces in the axial direction, and a core bar which is provided on the outer periphery is attached to the outer member in a fitted state and incorporates a magnetic sensor. An annular sensor holder in which the magnetic sensor is opposed to the magnetic encoder in the axial direction through a gap at a position inside the bearing in the axial direction relative to the magnetic encoder, and the sensor holder at a position outside the bearing in the axial direction relative to the magnetic encoder wherein a sealing device for sealing the space between the inner member, the magnetic encoder, magnets to be detected portion is a plastic magnetic encoder is a flop Rasuchi click magnet and,
The sensor holder is composed of the cored bar and an annular resin sensor holder that incorporates the magnetic sensor and is coupled to the cored bar.
The outer member is formed in a shape in which the inboard side end surface is recessed toward the outboard side from the inboard side end surface of the inner member, and the sensor holding body is provided in a recessed portion of the outer member. And
The core bar includes an outer diameter cylindrical portion that is press-fitted and attached to the outer peripheral surface of the outer member, a flange portion that extends from the inboard side end of the outer diameter cylindrical portion toward the inner diameter side, and an inner diameter side end of the flange portion. The sensor holder is fixed to the inboard side end of the outer member, with the flange portion in close contact with the inboard side end surface of the outer member.
The sensor holding body has a sensor embedded protrusion that protrudes inward from a hole formed in the inner diameter cylindrical portion of the core at the inner end of the bearing in the axial direction, and incorporates the magnetic sensor, A wheel bearing device with a rotation detecting device , wherein the resin sensor holding body is integrally molded at a portion extending from an inner diameter cylindrical portion to the flange portion . According to claim 1, wherein the plastic magnetic encoder, the flop Rasuchi click magnet is a multi-pole magnet arranged magnetic poles in a circumferential direction, the multi-pole magnet comprises a magnetic powder and a thermoplastic resin, the magnetic powder A wheel bearing device with a rotation detecting device, wherein the thermoplastic resin contains a melt viscosity of 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. In any one of claims 1 to 5, wherein the flop Rasuchi click magnet is injection-molded article rotation detector equipped wheel support bearing assembly of the plastic magnetic encoder. According to claim 6, wherein the flop Rasuchi click magnet of the plastic magnetic encoder is obtained by a magnetic field formed in an injection molding rotation detector equipped wheel support bearing assembly.   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 detector, which is a single piece of an annular plastic magnet having an L-shaped cross section.   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 integrally formed on the standing plate portion of the slinger.   10. The wheel with a rotation detecting device according to claim 9, wherein the plastic magnetic encoder is an insert molded product in which the plastic multi-pole magnet is integrally molded by injecting a thermoplastic resin containing magnetic powder into a mold in which the slinger is arranged. Bearing device.   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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