JP2005049359A - Bearing with magnetic encoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing with a magnetic encoder which a magnetization capable of a stable sensing can be performed, having an excellent abrasion resistance property and also excellent in a productivity. <P>SOLUTION: In a roller bearing in which a rolling body 3 intervenes between the orbital planes 1a and 2a of an inner member 1A and an outer member 2A, the magnetic encoder 10A is fitted to the circumference of the outer member 2A. The magnetic encoder 10A is constituted of a multipole magnet 14 in the outer diameter surface of a cylindrical arbor 11C so as to orient the multipole magnet 14 into a radial direction. The multipole magnet 14 is obtained by forming magnetic poles alternately in the circumferential direction, and comprises a sintered body by sintering a mixture powder of a magnetic powder and a non-magnetic metal powder. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a bearing provided with a magnetic encoder, such as a bearing provided with a magnetic encoder used for rotation detection, for example, a wheel bearing provided with a magnetic encoder for detecting the rotation speed of a wheel in an antilock brake system of an automobile.

Conventionally, the following structure is often used as an anti-skid rotation detection device for preventing automobile skid. That is, the rotation detection device is composed of a toothed rotor and a sensing sensor, and in this case, the rotation detection device is generally arranged apart from the seal device for sealing the bearing, and constitutes an independent rotation detection device. Is.
Such a conventional example has a structure in which a toothed rotor fitted to a rotating shaft is sensed and detected by a rotation detection sensor attached to a knuckle, and a bearing used is provided independently on the side thereof. Protected against intrusion of moisture or foreign matter by the sealed device.

As another example, Patent Document 1 discloses a bearing seal having a rotation detection device for detecting wheel rotation for the purpose of reducing the mounting space of the rotation detection device and dramatically improving the sensing performance. A structure is shown in which an elastic member mixed with magnetic powder is circumferentially vulcanized and bonded in the radial direction of a slinger to be used, and magnetic poles are alternately arranged there.
Further, in Patent Document 2, for the purpose of reducing the dimension in the axial direction, improving the degree of sealing between the rotating member and the fixed member, and enabling easy attachment, the gap between the rotating member and the fixed member is disclosed. Is shown, and a rotating disk is attached to the rotating member, and a multi-polar coder is attached to the rotating disk. The coder used is made of an elastomer to which magnetic particles are added, and the side surface of the coder is a sealing means that is substantially flush with the side surface of the fixing member.

A coder made of plastic (plastomer) containing magnetic powder or magnetic particles is shaped by using a mold suitable for the product shape, like conventional injection molding or compression molding. Or by forming a sheet by extrusion molding using a T-shaped die or sheet molding such as calendering and then punching it into a product shape, and then fixing it on a metal substrate with an adhesive You may make it. In this case, a metal substrate may be assembled in advance in a mold as in insert molding, and then a molten resin may be poured to simultaneously process the bonding process.
Japanese Patent No. 2816783 JP-A-6-281018 JP-A 63-115008 JP-A-63-300910

  However, among the above conventional examples, in the bearing seals shown in Patent Document 1 and Patent Document 2, an elastic member mixed with magnetic powder in the radial direction of the slinger used therein is vulcanized and bonded in a circumferential shape. In addition, if the coder is to be made into an elastomer with magnetic particles added as a coder built-in sealed structure with a multipolar coder attached, an elastomer or elastic member component that becomes a binder for holding magnetic powder or magnetic particles is required. Become. However, when an elastomer or elastic member component is used for the binder, a dispersion step is always required by kneading the magnetic powder or magnetic particles with the elastomer or elastic member before shaping into the coder shape. In this step, the binder component in the coder Since it is difficult to increase the relative content (volume fraction) of magnetic powder or magnetic particles, it is necessary to increase the thickness of the coder in order to obtain a magnetic force that is stably sensed by the magnetic sensor.

In addition, molding of elastic members and elastomeric coders containing magnetic powder and magnetic particles is performed by using a mold suitable for the product shape, such as injection molding and compression molding, and the vulcanization process is performed. When necessary, the vulcanization time required in the mold had to be maintained under pressure, requiring many steps in production.
In addition, elastic members and elastomeric coders containing magnetic powder and magnetic particles, for example, in bearing seals with a rotation detection device for detecting wheel rotation, reduce the mounting space for the rotation detection device and dramatically improve sensing performance. In order to improve the quality of the sensor, the sensor must be disposed at a position close to and opposite to the slinger used in the axial direction. However, in this case, if foreign particles such as sand particles enter the gap between the bearing seal surface on the rotating side and the surface of the sensing sensor on the fixed side while the vehicle is running, the elastic member and the elastomer coder surface will be worn. Severe damage was observed.

  In the case of a coder made of plastic (plastomer) containing magnetic powder or magnetic particles, it is manufactured by conventional injection molding, compression molding, sheet molding such as extrusion molding using T-shaped dies or calendar molding, and insert molding. If it is going to do, the synthetic resin component used as a binder for hold | maintaining magnetic powder and a magnetic particle will be needed. However, when a synthetic resin component is used for a binder, a dispersion step by kneading magnetic powder, magnetic particles, plastomer, and an elastic member is always required before shaping into a coder shape, like an elastomer. Again, in this process, the relative content (volume fraction) of magnetic powder and magnetic particles with respect to the binder component in the coder is difficult to increase, so the thickness of the coder is used to obtain a magnetic force that is stably sensed by the magnetic sensor. It was necessary to increase the dimensions. In addition, pre-molding materials produced by kneading magnetic powder, magnetic particles, plastomers, and elastic members in this way by conventional manufacturing methods are injected (injected) into the mold or compressed (compressed) to be applied to the coder. When forming, or by shaping by insert molding, etc., the magnetic particle component contained in the material is a metal oxide, so it is hard and wear of molds and molding machines becomes a problem in mass production. The pre-molding material with a high content of magnetic particle components has a problem that the melt viscosity becomes high and the molding load increases, such as increasing the molding pressure and the mold clamping force.

  Even in the case of sheet molding such as extrusion molding and calendar molding using a T-shaped die, the magnetic particle component contained in the material is hard with metal oxide, so that for mass production, T-shaped die and calendar molding machine Roll wear became a problem.

An object of the present invention is to provide a bearing with a magnetic encoder that can perform magnetization that enables stable sensing, has excellent wear resistance, and is excellent in productivity.
Another object of the present invention is to provide a bearing with a magnetic encoder, which is a wheel bearing for a magnetic encoder, capable of performing magnetization that enables stable sensing, excellent wear resistance, and excellent productivity. is there.

  A bearing with a magnetic encoder according to the present invention is a rolling bearing in which a rolling element is interposed between raceway surfaces of an outer member and an inner member, and a magnetic encoder is fitted to the outer periphery of the outer member. It is composed of a multipolar magnet having magnetic poles alternately formed in the circumferential direction, and this multipolar magnet is a sintered body obtained by sintering a mixed powder of magnetic powder and nonmagnetic metal powder. The magnetic encoder may be a multi-pole magnet provided on the outer periphery of a cylindrical cored bar.

According to this configuration, since the multipolar magnet is a sintered body obtained by sintering a mixed powder of magnetic powder and nonmagnetic metal powder, the following advantages can be obtained.
(1). Compared to conventional elastomers and plastomers, the magnetic powder ratio can be increased, so that the magnetic force per unit volume can be increased. As a result, the detection sensitivity can be improved and the wall thickness can be reduced.
(2). Compared to a conventional sintered magnet that is sintered only with magnetic powder, it is difficult to break due to the presence of non-magnetic metal powder as a binder.
(3). Since the surface is harder than conventional elastomers, etc., it is excellent in wear resistance and hardly damaged.
(Four) . Productivity is superior to conventional elastomers.

Even in the production of sintered compacts for multipolar magnets, the sintering method for mixed powders by dry blending of powders is a vulcanization process compared to injection molding and compression molding in the case of conventional elastomers and elastic members. In addition, since the molding load is small, the production process can be greatly simplified. Further, in the case of forming a green compact by sintering, problems such as wear of the mold do not occur as compared with injection molding or compression molding of an elastomer or an elastic member.
In addition, the multi-polar magnet sintered body can be attached to the metal core by a simple caulking process or a mechanical fixing method such as press-fitting, so even under severe conditions in a high and low temperature environment. Reliability can be maintained.
As described above, magnetic poles are alternately magnetized in the circumferential direction on the sintered body attached to the metal core to form a multipolar magnet.

  The magnetic encoder having the above configuration is used for rotation detection with a magnetic sensor facing a multipolar magnet. When this magnetic encoder is rotated, the passage of each magnetic pole of the multipolar magnet is detected by the magnetic sensor, and the rotation is detected in the form of pulses. Since the multi-pole magnet is made of a sintered body mixed with magnetic powder, as described above, the magnetic encoder can be made thin while securing a magnetic force to obtain stable sensing, and the magnetic encoder can be made compact and wear-resistant. In addition, since the metal cored bar and the multipolar magnet can be integrated by an assembling method such as caulking or press fitting, the fixing method is also excellent.

In this invention, the rolling bearing may be a wheel bearing. For example, an outer member having a double-row raceway surface formed on the inner periphery, an inner member having a raceway surface facing the raceway surface of the outer member on the outer periphery, and a composite member interposed between the two raceway surfaces. A wheel bearing that includes rolling elements in a row and rotatably supports the wheel with respect to the vehicle body may be used.
The wheel bearing may be a rotating member whose outer member has a wheel mounting flange.

In general, wheel bearings are exposed to the road surface environment, and particles such as sand particles may be caught between the magnetic encoder and the magnetic sensor that faces the magnetic encoder. Protected like.
That is, the surface hardness of the sintered multipolar magnet made of magnetic powder and nonmagnetic metal powder is harder than that of a conventional elastic member or elastomer coder containing magnetic powder or magnetic particles. For this reason, in a wheel bearing having a magnetic encoder for detecting wheel rotation, particles such as sand particles get caught in the gap between the surface of the rotating multipolar magnet and the surface of the stationary magnetic sensor during vehicle running. Even if rare, it has a significant reduction effect on wear damage of multipolar magnets.

The bearing with a magnetic encoder according to the present invention is a rolling bearing in which rolling elements are interposed between the raceway surfaces of the outer member and the inner member. A magnetic encoder is fitted on the outer periphery of the outer member. Since the multi-pole magnet is a sintered body made by sintering a mixed powder of magnetic powder and non-magnetic metal powder, the magnetic encoder can be magnetized for stable sensing, It is excellent in wear and productivity.
In particular, when applied to a wheel bearing, even if particles such as sand particles are caught in the gap between the surface of the rotating multipolar magnet and the surface of the stationary magnetic sensor during vehicle travel, the multipolar magnet There is a significant reduction effect on wear damage.

  A magnetic encoder according to a proposed example as the basis of the present invention will be described with reference to FIGS. As shown in FIG. 1, the magnetic encoder 10 includes a metal annular cored bar 11 and a multipolar magnet 14 provided on the surface of the cored bar 11 along the circumferential direction. The multipolar magnet 14 is a member that is magnetized in multiple poles in the circumferential direction and has magnetic poles N and S alternately formed, and is composed of a magnetic disk magnetized in multiple poles. The magnetic poles N and S are formed to have a predetermined pitch p in the pitch circle diameter PCD (FIG. 2). The magnetic encoder 10 is attached to a rotating member (not shown), and is used for rotation detection with a magnetic sensor 15 facing a multipolar magnet 14 as shown in FIG. The rotation detection device 20 is configured with the sensor 15. This figure shows an application example in which the magnetic encoder 10 is a component of a seal device 5 for a bearing (not shown), and the magnetic encoder 10 is attached to a bearing ring on the rotation side of the bearing. The seal device 5 includes a magnetic encoder 10 and a fixed-side seal member 9.

  The magnetic powder mixed in the multipolar magnet 14 may be isotropic or anisotropic ferrite powder such as barium-based and strontium-based. These ferrite powders may be granular powders or pulverized powders composed of a wet anisotropic ferrite core. When the pulverized powder made of this wet anisotropic ferrite core is used as a magnetic powder, it is necessary to use a mixed powder with a nonmagnetic metal powder as an anisotropic green body formed in a magnetic field.

  The magnetic powder may be a rare earth magnetic material. For example, samarium iron (SmFeN) magnetic powder and neodymium iron (NdFeB) magnetic powder, which are rare earth magnetic materials, may be used alone. The magnetic powder may be manganese aluminum (MnAl) gas atomized powder.

The magnetic powder may be a mixture of two or more of samarium iron (SmFeN) magnetic powder, neodymium iron (NdFeB) magnetic powder, and manganese aluminum (MnAl) gas atomized powder. For example, the magnetic powder is a mixture of samarium iron (SmFeN) magnetic powder and neodymium iron (NdFeB) magnetic powder, a mixture of manganese aluminum gas atomized powder and samarium iron magnetic powder, and samarium iron. Any of a mixture of a system magnetic powder, a neodymium iron system magnetic powder, and a manganese aluminum gas atomized powder may be used.
In addition, for example, when the magnetic force is insufficient with only the ferrite content, the required amount of samarium iron (SmFeN) magnetic powder or neodymium iron (NdFeB) magnetic powder, which is a rare earth magnetic material, is mixed with the ferrite powder to improve the magnetic force. It can also be manufactured at a low cost.

  In addition, the nonmagnetic metal powder forming the multipolar magnet 14 may be any one of powders of tin, copper, aluminum, nickel, zinc, tungsten, manganese, etc., or nonmagnetic stainless steel metal powder alone (one type). These powders, mixed powders of two or more, or alloy powders of two or more can be used.

Both the magnetic powder and the nonmagnetic metal powder have an average particle size of 10 μm to 150 μm, preferably 20 μm to 130 μm. If the average particle size of one or both of these powders is smaller than 10 μm, even if you try to obtain a green compact by pressing it in a mold at room temperature to make a mixed powder, it will mix well in the mold Powder may not flow in, and a green compact with a predetermined shape cannot be formed. In addition, if the average particle size of one or both of these powders is larger than 150 μm, even if an attempt is made to obtain a green compact by pressing it in a mold at room temperature as a mixed powder, the green compact strength Therefore, it cannot be removed from the mold and cannot be molded.
The above-mentioned average particle size range magnetic powder and non-magnetic metal powder are mixed at a predetermined mixing ratio using a powder mixer, and the mixed powder is pressed in a mold at room temperature. Obtain powder.

In the blending in the mixed powder forming the multipolar magnet 14, the volume blending ratio of the non-magnetic metal powder that is not magnetic powder is preferably 1 vol% or more and 90 vol% or less, preferably 5 vol% or more and 85 vol% or less, and more desirably 10 vol% or more and 80 vol% or less are good.
When the volume content of the nonmagnetic metal powder that is not magnetic powder is less than 1 vol%, the nonmagnetic metal powder is small as a metal binder, so that the multipolar magnet 14 obtained after sintering is hard but brittle. For this reason, as will be described later, even if the sintered body to be the multipolar magnet 14 is mechanically fixed on the core metal 11 by caulking or press-fitting, it is cracked. Moreover, since there are too few metal binders, a green compact may not be shape | molded.
If the volume content of the nonmagnetic metal powder that is not magnetic powder is more than 90 vol%, the magnetic component is relatively small, so that the magnetization strength of the obtained multipolar magnet 14 cannot be increased after sintering, and the magnetic encoder 10 Therefore, it is not possible to secure the magnetic force for obtaining the desired stable sensing.

The linear expansion coefficient of the multipolar magnet 14 obtained after sintering is preferably 0.5 × 10 ⁻⁵ or more and 9.0 × 10 ⁻⁵ or less, but preferably 0.8 × 10 ⁻⁵ or more and 7 × 10 ⁻⁵ or less, more preferably 0.9 × 10 ⁻⁵ or more and 5 × 10 ⁻⁵ or less.
For example, in the case of stainless steel (JIS standard SUS430), the linear expansion coefficient of the metal material used as the material of the core metal 11 is 1.0 × 10 ⁻⁵ . When the linear expansion coefficient of the multipolar magnet 14 is larger than 0.5 × 10 ⁻⁵ or smaller than 9 × 10 ⁻⁵ , the difference in linear expansion coefficient from the metal material that is the material of the core metal 11 is large. The difference in dimensional change when used in a high and low temperature environment becomes large, and the multipolar magnet 14 and the core metal 11 may interfere with each other and the multipolar magnet 14 may be damaged. Further, it becomes impossible to secure the multipolar magnet 14 and the cored bar 11.

In forming the green compact, a lubricant such as zinc stearate may be added to improve the green compact moldability when the magnetic powder and the nonmagnetic metal powder are blended.
These green compacts (green bodies) desirably have 5 to 30 vol% pores. Preferably it is 12-22 vol%, More preferably, it is 14-19 vol%. When the porosity is less than 5 vol%, the green compact may be damaged due to springback caused by recovery of elastic deformation of the raw material powder when the molding pressure is released. In addition, when the number of pores is more than 30 vol%, the mechanical strength of the sintered body is weakened, and as described later, even if it is attempted to be mechanically fixed on the core metal 11 by caulking or press fitting, etc. End up. In addition, the green compact may not be formed due to insufficient adhesion between the particles.

Since magnetic powder and non-magnetic metal powder are expensive, it is preferable that the plate thickness is thin. In view of compression moldability and handling, the preferred plate thickness is 0.3 mm to 5 mm, more preferably 0.6 mm to 3 mm. When the plate thickness is less than 0.3 mm, it is difficult to fill the mold and it is difficult to obtain a green molded body. Moreover, since the obtained green molded object may also be damaged at the time of handling, it is not preferable. On the other hand, when the green molded body is thicker than 10 mm, the moldability and handling are improved, but it is disadvantageous in terms of cost. On the other hand, when the thickness is too thick, uneven density of the green molded body tends to occur, and deformation after firing tends to occur. From these points, the plate thickness is preferably 0.3 mm to 5 mm.
The obtained green molded body is heated and sintered in a furnace as shown in FIG. 4 to form a disk-shaped sintered body. The heating and sintering in the furnace may be performed in an electric furnace in the atmosphere, or may be performed in a pusher furnace or an inert furnace while flowing an inert gas in a vacuum furnace.

The sintered body forming the magnetic encoder 10 may be provided with a rust preventive coating 22 as shown in FIG. In other words, the rust preventive film 22 is an anticorrosive film. The rust-proof coating 22 can be a clear high anti-corrosion paint. This paint can also be expected to have an effect as an adhesive between the core metal 11 and the sintered body, and penetrates into the pores of the surface layer of the sintered porous body and is suitably held on the surface by the anchor effect of the clear coating film component. Even during long-term use, good adhesion can be maintained as a rust-proof coating layer.
Examples of clear anticorrosive paints include modified epoxy paints, modified epoxy phenol curable paints, epoxy melamine paints, and acrylic paints. Among these, a modified epoxy phenol curing type and epoxy melamine type clear coating are particularly suitable.
Also, apply the clear to vacuum or impregnation (dipping), spray (spray) coating, electrostatic coating, etc. on fat or washed sintered body, and adhere to the sintered body by natural or forced air drying. The solvent component in the clear is removed, and the clear layer is baked on the sintered body under a predetermined baking condition (temperature and time), so that the rust preventive coating 22 is applied to the surface of the multipolar magnet 14 as shown in FIG. May be formed. The rust preventive coating 22 may be formed on the entire surface of the magnetic encoder 10. When this magnetic encoder 10 is attached to, for example, a wheel bearing, the film thickness of the anticorrosion (corrosion) film formed as described above is not particularly limited as long as it can satisfy the corrosion resistance required for the wheel bearing. However, 0.5 μm or more is desirable.
When used as a wheel bearing, if sand particles or the like are caught in the gap between the magnetic sensor 15 and the surface of the magnetic encoder 10, the surface of the magnetic encoder 10 may be damaged. If the thickness of the coating is thinner than 0.5 μm, the scratches may reach the sintered body as the base material, and the generation of rust from there may not be prevented.

  The metal that is the material of the core metal 11 is preferably a magnetic material, particularly a metal that is a ferromagnetic material. For example, a steel plate that is magnetic and has rust prevention properties is used. As such a steel plate, a ferritic stainless steel plate (JIS standard SUS430 series or the like), a rust-proof rolled steel plate, or the like can be used.

The shape of the core metal 11 can be various annular shapes, but a shape capable of fixing the multipolar magnet 14 is preferable. In particular, a shape capable of performing mechanical fixing such as caulking and fitting fixing is preferable.
In the case of caulking and fixing, for example, as shown in FIG. 1B, the core metal 11 includes an inner diameter side cylindrical portion 11a serving as a fitting side, an upright plate portion 11b extending from one end to the outer diameter side, The cross section formed by the other cylindrical portion 11c of the radial edge has a generally inverted Z-shaped annular shape.
Moreover, although the core metal 11 is made of a steel plate press-formed product in each of the above examples, the core metal 11 may be made of a machined product such as a steel material.

  The mixed magnetic powder sintered magnet disk provided along the circumferential direction on the metal core 11 that is a metal annular member as described above becomes a multipolar magnet 14 by being magnetized in multiple directions in the circumferential direction. The magnet 14 and the cored bar 11 constitute a magnetic encoder 10. In this case, the mixed magnetic powder sintered magnet disk (sintered body) mixed with magnetic powder using nonmagnetic metal powder as a binder is adjusted with a powder mixer while adjusting the composition ratio of the nonmagnetic metal powder and magnetic powder. By dispersing, a dry blend of powders can be obtained. Therefore, the relative content rate (volume fraction) of the magnetic powder in the sintered body can be increased. Therefore, the magnetic force stably sensed by the magnetic sensor 15 (FIG. 3) can be easily obtained, and it is not necessary to make the multipolar magnet 14 thick.

As described above with reference to FIG. 3, the magnetic encoder 10 having this configuration is used for rotation detection with the magnetic sensor 15 facing the multipolar magnet 14. When the magnetic encoder 10 is rotated, the magnetic sensor 15 detects the passage of the magnetic poles N and S magnetized in the multipole of the multipolar magnet 14, and the rotation is detected in the form of pulses. The pitch p (FIG. 2) of the magnetic poles N and S can be set finely. For example, it is possible to obtain an accuracy that the pitch p is 1.5 mm and the pitch difference is ± 3%, thereby enabling highly accurate rotation detection. The pitch mutual difference is a value indicating a difference in distance between the magnetic poles detected at a position away from the magnetic encoder 10 by a predetermined distance as a ratio to the target pitch. When the magnetic encoder 10 is applied to the bearing seal device 5 as shown in FIG. 3, the rotation of the bearing to which the magnetic encoder 10 is attached is detected.
Since the multi-pole magnet 14 is made of a sintered body (mixed magnetic powder sintered disk) mixed with magnetic powder, the magnetic pole can be thinned while securing a magnetic force to obtain stable sensing as shown below. 10 can be made compact, and it is excellent in wear resistance and productivity.

Furthermore, the surface hardness of the multipolar magnet 14 is harder than that of an elastic member or elastomer coder containing conventional magnetic powder or magnetic particles. For this reason, when applied to the rotation detection device 20 for detecting wheel rotation, particles such as sand particles bite into the gap between the surface of the rotation-side multipolar magnet 14 and the surface of the stationary-side magnetic sensor 15 during vehicle travel. Even if it is inserted, wear damage of the multipolar magnet 14 hardly occurs, and there is a significant reduction effect of wear as compared with a conventional elastic body.
The flatness of the surface of the mixed magnetic powder sintered magnet disk that becomes the multipolar magnet 14 provided along the circumferential direction on the metal core 11 that is a metal annular member is preferably 200 μm or less, and preferably 100 μm or less. . When the flatness of the disk surface is higher than 200 μm, the gap between the magnetic sensor 15 and the disk surface (air gap) changes during the rotation of the magnetic encoder 10, thereby degrading the sensing accuracy.
For the same reason, the surface runout of the mixed magnetic powder sintered magnet disk surface during rotation of the magnetic encoder 10 is preferably 200 μm or less, and preferably 100 μm or less.

  Next, the magnetic encoder bearing according to one embodiment of the present invention is applied with FIG. This embodiment is an example applied to a wheel bearing. This wheel bearing is a rolling bearing in which the outer member 2A of the inner member 1A and the outer member 2A is a rotating member, and the wheel mounting flange 26 is provided on the outer member 2A. The inner member 1A and the outer member 2A have double-row raceway surfaces 1a and 2a, respectively, and the rolling elements 3 are interposed between the opposed raceway surfaces 1a and 2a. The inner member 1A includes a pair of split inner rings 18A and 19A. Sealing devices 13 and 5A for sealing the end annular space are provided between the inner and outer members 1 and 2.

The magnetic encoder 10A has a configuration in which the multipolar magnet 14 is provided on the outer diameter surface of the cylindrical metal core 11C so that the multipolar magnet 14 faces in the radial direction. The magnetic encoder 10 is provided by being fitted to the outer diameter surface of the outer member 2A in the wheel bearing. A magnetic sensor 15 is provided to face the multipolar magnet 14.
The magnetic encoder 10A is formed so that the multipolar magnet 14 faces in the radial direction as described above, and is provided on the outer diameter surface of the cylindrical metal core 11C. Other configurations are shown in FIGS. This is the same as the proposed example described with reference to FIG. That is, the multipolar magnet 14 is a sintered body obtained by sintering a mixed powder of magnetic powder and nonmagnetic metal powder, and the above-mentioned proposed example is also used for the material and blending ratio of the magnetic powder and nonmagnetic metal powder. The items described in the above can be adopted.

  According to the wheel bearing of this configuration, similarly to the above-described proposal example, the magnetic encoder 10A can be magnetized so that stable sensing can be performed, and can be excellent in wear resistance and productivity.

(A) is a fragmentary perspective view of the magnetic encoder based on the proposal example used as the foundation of this invention, (B) is a fragmentary perspective view which shows the assembly process of the magnetic encoder. It is explanatory drawing of the magnetic pole which shows the same magnetic encoder from the front. It is a partial fracture front view showing a sealing device provided with the magnetic encoder and a magnetic sensor. It is process drawing which uses a green body as a sintered compact. It is a fragmentary perspective view of the other proposal example of a magnetic encoder. It is sectional drawing of the bearing with a magnetic encoder which is a wheel bearing concerning one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Inner member 2 ... Outer member 1A ... Inner member 2A ... Outer member 3 ... Rolling element 10 ... Magnetic encoder 10A ... Magnetic encoder 14 ... Multipolar magnet 15 ... Magnetic sensor

Claims (4)

  In a rolling bearing in which rolling elements are interposed between the raceway surfaces of the outer member and the inner member, a magnetic encoder is fitted to the outer periphery of the outer member, and the magnetic encoder alternately forms magnetic poles in the circumferential direction. A bearing with a magnetic encoder, which is composed of a multipolar magnet, and is a sintered body obtained by sintering a mixed powder of magnetic powder and nonmagnetic metal powder.   2. The bearing with a magnetic encoder according to claim 1, wherein the magnetic encoder is provided with a multipolar magnet on an outer periphery of a cylindrical cored bar.   3. The rolling bearing according to claim 1, wherein the rolling bearing has an outer member formed with a double-row raceway surface on the inner periphery, and an inner member formed with a raceway surface facing the raceway surface of the outer member on the outer periphery. And a bearing with a magnetic encoder, which is a wheel bearing for supporting the wheel rotatably with respect to the vehicle body.   4. The bearing with a magnetic encoder according to claim 3, wherein the wheel bearing is a rotating member whose outer member has a wheel mounting flange.

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