JP2007010682A - Magnetic encoder and bearing for wheel equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic encoder capable of thinning a wall thickness while providing excellent detection sensitivity, and capable of selecting a proper material to secure moldability. <P>SOLUTION: The magnetic encoder 10 is provided with a multi-pole magnet 14 with magnetic poles formed alternately along a circumferential direction, and a mandrel 11 for supporting the multi-pole magnet 14. The multi-pole magnet 14 comprises a mixture with magnetic powder mixed in a plastomer such as a plastic, and a blended amount of the magnetic powder is 30-80 vol%. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic encoder used for a rotation detecting device for a bearing portion that rotates relatively, and a wheel bearing provided with the same, for example, a rotation detecting device that detects front and rear wheel rotation speeds in an antilock brake system of an automobile The present invention relates to a magnetic encoder provided.

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 to 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 powder is added.
Japanese Patent No. 2816783 Japanese Published Unexamined Patent Application No. 6-281018

Considering the improvement of the magnetic characteristics, it is preferable that the amount of the magnetic substance contained in the magnetic encoder is large. This is because the magnetic force per unit area can be increased, so that the magnetic encoder can be thinned and the detection sensitivity can be improved. In particular, the magnetic properties are improved when the rare earth magnetic powder is used rather than the ferrite magnetic powder.
However, when the base material is an elastomer or plastomer, the blending amount of the rare earth magnetic powder cannot be increased. This is because the following problem has occurred in the mixing process of the base material and the rare earth magnetic powder. Even when ferrite magnetic powder is used, the same problem as in the case of rare earth magnetic powder occurs.
(1). When the blending amount of magnetic powder is large, the processing machine (kneading machine) is greatly damaged. The rotational torque increases and a large load is applied to the apparatus, or the wear of the roll is significantly damaged by contact with hard magnetic powder.
(2). Due to the heat generated during processing, the magnetic powder is oxidized and the magnetic properties are deteriorated.

An object of the present invention is to provide a magnetic encoder that can be thinned while obtaining excellent detection sensitivity and is excellent in moldability.
Another object of the present invention is to provide a wheel bearing capable of detecting rotation with a compact configuration without increasing the number of parts.

The magnetic encoder of the present invention is a magnetic encoder comprising a multipolar magnet made of plastic magnets having magnetic poles alternately formed in the circumferential direction and a cored bar that supports the multipolar magnet, wherein the multipolar magnet is a plastomer. The magnetic powder is mixed with the magnetic powder, and the blending amount of the magnetic powder of this multipolar magnet is 30 to 80 vol%.
The multipolar magnet is, for example, an annular shape such as an annular shape or a disc shape. The core metal is also formed in an annular shape such as an annular shape or a disc shape.
The magnetic encoder having this 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 blending amount of the magnetic powder is 30 to 80 vol%, the multipolar magnet can be thinned while obtaining excellent detection sensitivity, and moldability can be ensured by selecting an appropriate material. If the blending amount of the magnetic powder of the multipolar magnet is less than 30%, the residual magnetic flux density is low and the thickness cannot be reduced. However, since it is 30% or more, the magnetic force that enables stable detection is ensured even if the thickness is reduced. it can. Moreover, if the blending amount of the magnetic powder exceeds 80%, molding is very difficult or impossible, but since it is less than 80%, by appropriately selecting the material of the non-magnetic material component, Formability is ensured.

  The magnetic powder may be ferrite powder. Ferrite powder is cheaper than other magnetic powders, and using this, a magnetic encoder can be manufactured at low cost. The ferrite powder may be a granular powder or a pulverized powder of a wet anisotropic ferrite core. The pulverized powder of the wet anisotropic ferrite core can be made into a highly oriented high-strength magnetic powder compared to other ferrite powders, can be made thinner, and when the multipolar magnet is made into a ring shape, it is thinner and has a larger diameter. The ring-shaped sintered body can be made.

  The magnetic powder may be a rare earth magnetic powder. For example, a samarium-based magnetic powder or a neodymium-based magnetic powder may be used. When these samarium magnetic powder and neodymium magnetic powder are used, a strong magnetic force can be obtained. As the samarium-based magnetic powder, samarium iron (SmFeN) -based magnetic powder is used, and as the neodymium-based magnetic powder, neodymium iron (NdFeB) -based magnetic powder is used. In addition, the magnetic powder may be manganese aluminum (MnAl) gas atomized powder.

In the present invention, the magnetic powder may include two or more kinds of magnetic powder.
When two or more kinds of magnetic powders are included, desired characteristics can be obtained by arbitrarily mixing a plurality of kinds of powders. For example, when the magnetic force is insufficient with ferrite powder alone, it can be manufactured at low cost while improving the magnetic force by mixing ferrite powder with the required amount of rare earth magnetic material samarium magnetic powder or neodymium magnetic powder. .

  The wheel bearing according to the present invention includes the magnetic encoder having any one of the above-described configurations according to the present invention. Since the magnetic encoder according to the present invention can be thinned while securing a magnetic force for obtaining stable sensing, by providing this for a wheel bearing, it becomes a wheel bearing capable of detecting rotation with a compact configuration.

In the wheel bearing according to the present invention, the constituent element of the seal device for sealing the bearing space may be a magnetic encoder. For example, this wheel bearing includes an outer member in which double-row rolling surfaces are formed on the inner peripheral surface, an inner member in which a rolling surface opposite to the rolling surface of the outer member is formed, A wheel bearing having a double row rolling element interposed between rolling surfaces and rotatably supporting the wheel with respect to the vehicle body, wherein the annular space between the outer member and the inner member is sealed. A sealing device may be provided.
In this case, the seal device is opposed to the first seal plate having an L-shaped cross section that is fitted to the rotation side member of the outer member or the inner member, and the first seal plate. A side lip that is slidably in contact with the upright plate portion of the first seal plate, comprising a second seal plate having an L-shaped cross section that is fitted to the fixed member of the outer member or the inner member, and A radial lip that is in sliding contact with a cylindrical portion is fixed to the second seal plate, the first seal plate is a core metal in the magnetic encoder, and the multipole magnet is provided on the standing plate portion. Also good.
In the case of the wheel bearing of this configuration, since the component of the seal device is a magnetic encoder, the rotation of the wheel can be detected with a more compact configuration without increasing the number of parts. Further, an excellent sealing effect can be obtained, for example, by the side lip and radial lip fixed to the second seal plate being in sliding contact with the first seal plate.

The magnetic encoder of the present invention is a magnetic encoder comprising a multipolar magnet composed of plastic magnets having magnetic poles alternately formed in the circumferential direction, and a cored bar that supports the multipolar magnet, wherein the multipolar magnet is a plastomer. This is a mixture of magnetic powder and the amount of magnetic powder in this multipolar magnet is 30 to 80 vol%, so it is possible to reduce the thickness while obtaining excellent detection sensitivity, and select an appropriate material. By doing so, moldability can be secured.
The wheel bearing of the present invention can perform stable rotation detection with a compact configuration.

  A first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the magnetic encoder 10 includes an annular metal core 11 made of metal and a multipolar magnet 14 made of a plastic magnet provided on the surface of the core 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. A specific configuration of the sealing device 5 will be described later.

The multipolar magnet 14 is formed by mixing non-magnetic powder as a base material with plastomer and mixing magnetic powder therein.
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.

  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 magnetic powder, a neodymium iron 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 the blending in the mixed powder forming the multipolar magnet 14, the blending amount of the magnetic powder is required to be 20 to 90 vol%, but in this invention, it is set to 30 to 80 vol%. If the blending amount of the magnetic powder of the multipolar magnet 14 is less than 30%, particularly less than 20%, the residual magnetic flux density is low and the thinning cannot be performed. However, it is possible to secure a magnetic force that enables stable detection. Further, if the blending amount of the magnetic powder exceeds 90%, molding is very difficult or impossible, but if it is less than 90%, particularly less than 80%, moldability is ensured.

  Since magnetic powder is 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.

  The sintered body forming the magnetic encoder 10 may be provided with a rust-proof 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.

  The metal that is the material of the core metal 11 is preferably a magnetic material, particularly a metal that is a ferromagnetic material. 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 cored bar 11 is composed of a cylindrical portion 11a on the inner diameter side serving as a fitting side and a standing plate portion 11b extending from one end thereof to the outer diameter side. It is an annular shape with an L-shaped cross section. In this example, the other cylinder part 11c further extends from the outer diameter edge of the standing plate part 11b. If this other cylinder portion 11c is included, the cross-sectional shape of the cored bar 11 is generally an inverted Z shape.
The cylindrical portion 11a, the upright plate portion 11b, and the other cylindrical portion 11c are integrally formed by pressing from a metal plate such as a steel plate. The standing plate portion 11b is formed flat, and a non-magnetized sintered body of the multipolar magnet 14 is built on the surface of the flat standing plate portion 11b, and the other cylindrical portion 11c of the outer peripheral edge is crimped. Thus, the multipolar magnet 14 is fixed in an overlapping state with the standing plate portion 11 b of the core metal 11. The other cylindrical portion 11c has a crimped portion at the front end side portion or substantially the whole in its cross section. Further, this caulking portion extends over the entire circumference of the core metal 11 and thus has an annular shape. The portion fixed by the other cylindrical portion 11 c that is the crimping portion of the multipolar magnet 14 is a recessed portion 14 a that is recessed from the surface to be detected of the multipolar magnet 14, and the crimping portion of the core metal 11. The other cylindrical portion 11c is configured not to protrude from the surface to be detected of the multipolar magnet 14. The recessed portion 14 a is formed as a stepped portion that is slightly retracted to the back side from the surface to be detected of the multipolar magnet 14. A portion of the outer peripheral edge of the multipolar magnet 14 on the back side with respect to the recessed portion 14a is a curved surface having a circular cross section, and a crimped portion of the other cylindrical portion 11c is formed along the curved surface portion. In addition to performing the outer peripheral portion of the multipolar magnet 14 over the entire circumference as described above, the caulking and fixing may be partial caulking performed at a plurality of locations in the circumferential direction.

  For example, as shown in FIG. 5, the core metal 11 may be formed in an annular shape having an L-shaped cross section including a cylindrical portion 11 a on the inner diameter side and a standing plate portion 11 b ″ that extends low from one end to the outer diameter side. The cylindrical portion 11a and the upright plate portion 11b ″ are integrally formed by pressing from a metal plate such as a steel plate. The upright plate portion 11b ″ is formed flat, and a disk-like sintered body that becomes the multipolar magnet 14 is press-fitted and fixed to the outer periphery of the cylindrical portion 11a up to the flat upright plate portion 11b ″. The height of the upright plate portion 11b "is a height that hits the vicinity of the inner peripheral portion of the multipolar magnet 14, and is lower than the example of FIG.

Further, in each of the above examples, the core metal 11 is made of a steel plate press-formed product. However, as shown in FIG. 6, the core metal 11 may be made of a machined product such as a steel material. The cored bar 11 in the example of the figure has the groove 11ba of the standing plate 11b as a cutting groove.
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.

  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 shaft ring to which the magnetic encoder 10 is attached is detected.

  Since the blending amount of the magnetic powder is 30 to 80 vol%, the multipolar magnet 14 can be thinned and can secure moldability while ensuring excellent detection sensitivity, that is, a magnetic force capable of obtaining stable sensing. . If the blending amount of the magnetic powder of the multipolar magnet 14 is less than 20%, the residual magnetic flux density is low and the thickness cannot be reduced, but if it is 20% or more, especially 30% or more, stable detection is possible even if the thickness is reduced. Can be obtained.

A test example will be described. As shown in Table 1 below, formulation examples (1) to (8) are examples of sintered magnetic encoders. The nonmagnetic metal powder was tin powder, the magnetic powder was samarium-iron powder, the blending ratio was as shown in Table 1, a test piece of φ25 mm × 3.2 mm was manufactured, and the residual magnetic flux density was measured. The results are also shown in Table 1. The moldability and handling properties of the test pieces (◯: good, Δ: average, x: bad) are also shown. The handling property is the handling property when the green body in which the mixed powder is hardened is taken out from the mold.
From Table 1, the residual magnetic flux density, molding processability, and handling properties were good at all the blending ratios of blending examples (2) to (7) (range of blending amount of magnetic powder 30 to 80). The residual magnetic flux density was judged to be good if it was 200 mT or more required as an operating range as a magnetic encoder.
Formulation example (8) is an example in which the blending amount of magnetic powder is reduced to 10 vol%, and the moldability and handling properties are good, but the residual magnetic flux density is 170 mT, and the operating range as a magnetic encoder (200 mT) It was slightly less than. Formulation Example (1) is an example in which the blending amount of the magnetic powder was increased to 95 vol%, and molding was impossible.
From these results, when the multipolar magnet is a sintered body, the lower limit of the preferable blending amount of the magnetic powder is 10 vol%, which is a value that makes the residual magnetic flux density insufficient, and a good residual magnetic flux density. The upper limit of the preferable blending amount is considered to be 90 vol% when viewed as the intermediate between 95 vol%, which is the above-mentioned unmoldable value, and 80 vol%, which is a good moldability value. The

Formulation examples (9) to (14) in Table 2 are examples of rubber magnets. A nonmagnetic powder was used as an elastomer, a magnetic powder was used as a samarium-iron-based powder, the blending ratio was as shown in Table 2, a test piece of a sintered body of φ25 mm × 3.2 mm was manufactured, and the residual magnetic flux density was measured. The results are also shown in Table 2.
In the case of the blending examples (9) to (12), since the blending amount of the magnetic powder was large, the rotational torque of the apparatus was large and the moldability was poor. In the case of Formulation Example (14), the residual magnetic flux density is the lower limit value (200 mT) of the operating range, but the moldability and handling properties are slightly poor.
From this result, when it is set as a rubber magnet, it is thought that the compounding quantity of a preferable magnetic powder is less than 30 vol%.

  From the results of Tables 1 and 2, the value of the residual magnetic flux density depends on the blending amount of the magnetic powder, and the preferable blending amount range of the magnetic powder as viewed from the residual magnetic flux density is 20 vol% or more, more preferably 30 vol% or more. It is thought. Although the moldability and handling properties are greatly affected by the difference in non-magnetic powder, it is considered that the preferred range of blending amount is 90 vol% or less, more preferably 80 vol% or less, as arbitrary non-magnetic powder can be selected. The Therefore, the range of the preferable compounding quantity of magnetic powder is 20-90 vol%, More preferably, it is 30-80 vol%. Although the above test examples have been described for the case of a sintered magnet and the case of a rubber magnet, the case of a plastic magnet is considered to be the same as that of a rubber magnet.

  Next, an example of a wheel bearing provided with the magnetic encoder 10 and an example of the seal device 5 will be described with reference to FIGS. As shown in FIG. 7, the wheel bearing includes an inner member 1 and an outer member 2, a plurality of rolling elements 3 accommodated between the inner and outer members 1 and 2, and the inner and outer members 1 and 2. Sealing devices 5 and 13 for sealing the end annular space. The sealing device 5 at one end is provided with a magnetic encoder 10. The inner member 1 and the outer member 2 have raceway surfaces 1a and 2a of the rolling element 3, and each raceway surface 1a and 2a is formed in a groove shape. The inner member 1 and the outer member 2 are an inner peripheral member and an outer peripheral member that are rotatable with respect to each other via the rolling elements 3, respectively. An assembly member in which the bearing inner ring and the bearing outer ring are combined with another component may be used. Further, the inner member 1 may be a shaft. The rolling element 3 is composed of a ball or a tapered roller, and a ball is used in this example.

  This wheel bearing is a double-row rolling bearing, more specifically, a double-row angular contact ball bearing, and the inner ring of the bearing is a pair of split type in which the raceway surfaces 1a and 1a of the respective rolling element rows are respectively formed. It consists of inner rings 18 and 19. The inner rings 18 and 19 are fitted to the outer periphery of the shaft portion of the hub ring 6 and constitute the inner member 1 together with the hub ring 6. The inner member 1 is integrated with the hub ring 6 and one inner ring 18 instead of the three-piece assembly part including the hub ring 6 and the pair of split inner rings 18 and 19 as described above. A hub ring with a raceway surface, that is, a hub ring in which the raceway surface 1a is directly formed on the outer periphery, and the other inner ring 19 may be used.

One end (for example, an outer ring) of the constant velocity universal joint 7 is connected to the hub wheel 6, and a wheel (not shown) is attached to the flange portion 6 a of the hub wheel 6 with a bolt 8. The other end (for example, inner ring) of the constant velocity universal joint 7 is connected to the drive shaft.
The outer member 2 includes a bearing outer ring, and is attached to a housing (not shown) including a knuckle or the like in the suspension device. The rolling elements 3 are held by a holder 4 for each row.

  FIG. 8 shows an enlarged view of the sealing device 5 with a magnetic encoder. The sealing device 5 is the same as that shown in FIG. 3, and a part of the sealing device 5 has been described above, but the details will be described with reference to FIG. The sealing device 5 is attached to a rotating member of the inner member 1 and the outer member 2 with the magnetic encoder 10 or its core 11 serving as a slinger. In this example, since the rotation-side member is the inner member 1, the magnetic encoder 10 is press-fitted and attached to the outer peripheral surface of the inner member 1.

  This sealing device 5 has annular sealing plates (11), 12 made of first and second metal plates attached to the inner member 1 and the outer member 2, respectively. The first seal plate (11) is the core metal 11 in the magnetic encoder 10 and will be described as the core metal 11 below. The magnetic encoder 10 is according to the first embodiment described above with reference to FIGS. 1 to 3, and redundant description thereof is omitted. The rotation detection device 20 for detecting the wheel rotation speed is configured by arranging the magnetic sensor 15 as shown in the figure so as to face the multipolar magnet 14 in the magnetic encoder 10.

The second seal plate 12 is a member constituting the seal member 9 (FIG. 3), and a side lip 16a and a cylinder which are in sliding contact with the inner surface of the standing plate portion 11b of the core metal 11 which is the first seal plate. Radial lips 16b and 16c that are in sliding contact with the portion 11a are integrally provided. The lips 16 a to 16 c are provided as a part of the elastic member 16 that is vulcanized and bonded to the second seal plate 12. The number of the lips 16a to 16c may be arbitrary, but in the example of FIG. 8, one side lip 16a and two radial lips 16c and 16b positioned inside and outside in the axial direction are provided. The second seal plate 12 is configured such that an elastic member 16 is held in a fitting portion with the outer member 2 that is a fixed side member. That is, the elastic member 16 has a tip cover portion 16d that covers from the inner diameter surface of the cylindrical portion 12a to the outer diameter of the tip portion, and this tip cover portion 16d is formed between the second seal plate 12 and the outer member 2. It is interposed in the fitting part, and the sealing degree of this fitting part is improved.
The cylindrical portion 12a of the second seal plate 12 and the other cylinder portion 11c of the core metal 11 serving as the first seal plate are opposed to each other with a slight radial gap, and the labyrinth seal 17 is configured by the gap.

According to the wheel bearing of this configuration, the rotation of the inner member 1 rotating together with the wheel is detected by the magnetic sensor 15 via the magnetic encoder 10 attached to the inner member 1, and the wheel rotation speed is detected. The
Since the magnetic encoder 10 is a constituent element of the sealing device 5, the rotation of the wheel can be detected without increasing the number of parts. Further, the space at the bearing end portion of the wheel bearing 5 is a narrow space limited by the constant velocity joint 7 and the bearing support member (not shown) in the periphery, but the multipolar magnet 14 of the magnetic encoder 10 is the above-described space. Therefore, the rotation detector 20 can be easily arranged.
As for the seal between the inner and outer members 1 and 2, the first seal plate is used for sliding contact of the seal lips 16 a to 16 c provided on the second seal plate 12 and the cylindrical portion 12 a of the second seal plate 12. It is obtained with the labyrinth seal 17 configured by facing the other cylindrical portion 11c of a certain core metal 11 with a slight radial gap.

In the wheel bearing shown in FIGS. 7 and 8, the core 11 of the magnetic encoder 10 is shown as having the shape of FIG. 1, but the magnetic encoder 10 is shown in FIGS. 4 to 6. Each example may be used.
Further, when the magnetic encoder 10 is used as a component of the bearing seal device 5, the multipolar magnet 14 may be provided inward with respect to the bearing, contrary to the above embodiments. That is, the multipolar magnet 14 may be provided on the inner surface of the bearing of the core metal 11. In that case, the cored bar 11 is preferably made of a non-magnetic material.

  Furthermore, the magnetic encoder 10 is not limited to the one in which the multipolar magnets 14 are directed in the axial direction as in the above embodiments, and may be provided in the radial direction, for example, as shown in FIG. In the example shown in the drawing, a second cylindrical portion 11d extending outward in the axial direction from the standing plate portion 11b is provided on a core metal 11A which is a sealing plate serving as a slinger of the sealing device 5, and the second cylindrical portion 11d A multipolar magnet 14 is fixed to the outer periphery. That is, a crimping plate portion 11e extending to the outer diameter side is integrally provided at the tip of the second cylindrical portion 11d, and the second cylindrical portion is attached to the multipolar magnet 14 by crimping the crimping plate portion 11e. It is fixed to the outer peripheral surface of 11d. The upright plate portion 11b extends from the cylindrical portion 11a to the outer diameter side. That is, the metal core 11A in this example is added from the tip of the second cylindrical portion 11d to a substantially inverted Z-shaped section in which the cylindrical portion 11a, the standing plate portion 11b, and the second cylindrical portion 11d are successively connected. The fastening plate portion 11e has a shape extending integrally to the outer diameter side. The magnetic sensor 15 is disposed facing the multipolar magnet 14 in the radial direction.

The magnetic encoder 10 in each of the above embodiments has been described as a component of the bearing seal device 5. However, the magnetic encoder 10 of each of the embodiments is a component of the seal device 5. Not limited to this, it can be used alone for rotation detection. For example, the magnetic encoder 10 in the embodiment of FIG. 1 may be provided in the bearing separately from the seal device 5.
As shown in FIG. 10, the magnetic encoder 10A may have 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. . In this case, the magnetic encoder 10 may be provided by being fitted to the outer diameter surface of the outer member 2A in the wheel bearing. The wheel bearing shown in FIG. 2 is one in which the outer member 2A of the inner member 1A and the outer member 2A is a rotating side member, and the wheel mounting flange 26 is provided on the outer member 2A. The seal device 5A is provided on the bearing separately from the magnetic encoder 10A. The inner member 1A includes a pair of split inner rings 18A and 19A.

(A) is a fragmentary perspective view of the magnetic encoder which concerns on 1st Embodiment 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 axial direction fracture | rupture sectional view which shows the sealing device provided with the magnetic encoder, and a magnetic sensor. It is a fragmentary perspective view of the magnetic encoder which concerns on other embodiment of this invention. It is a fragmentary perspective view of the magnetic encoder which concerns on other embodiment of this invention. It is a fragmentary perspective view of the magnetic encoder which concerns on other embodiment of this invention. It is a sectional view of the whole wheel bearing provided with the magnetic encoder concerning a 1st embodiment. It is a fragmentary sectional view of the bearing for the wheels. It is sectional drawing of the magnetic encoder part of the wheel bearing which concerns on further another embodiment of this invention. It is sectional drawing of the wheel bearing which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1A ... Inner member 2, 2A ... Outer member 3 ... Rolling body 5 ... Sealing device 10 ... Magnetic encoder 11, 11A, 11B ... Core metal (1st sealing board)
11a ... cylindrical portion 11b ... standing plate portion 12 ... second seal plate 14 ... multipolar magnet 15 ... magnetic sensor 16a ... side lips 16b, 16c ... radial lip 20 ... rotation detector

Claims (3)

  In a magnetic encoder comprising a multipolar magnet composed of plastic magnets having magnetic poles alternately formed in the circumferential direction and a cored bar that supports the multipolar magnet, the multipolar magnet is obtained by mixing magnetic powder into a plastomer. A magnetic encoder characterized in that the amount of magnetic powder of this multipolar magnet is 30 to 80 vol%.   The magnetic encoder according to claim 1, wherein the multipolar magnet has a disk shape. A wheel bearing comprising the magnetic encoder according to claim 1.

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