WO2010013411A1 - Bearing device adapted for use in wheel and equipped with rotation sensing device - Google Patents

Abstract

A bearing device adapted for use in a wheel and equipped with a rotation sensing device is compact in size and enables accurate sensing of rotation by preventing wear, swelling, and positional displacement of a magnetic encoder.  A bearing device for a wheel, having rolling bodies (5) mounted between a rolling surface (3) on the inner periphery of an outer member (1) and a rolling surface (4) on the outer periphery of an inner member (2), wherein a magnetic encoder (21) is mounted to the outer peripheral surface of the inner member (2).  A sensor holder (25) incorporating a magnetic sensor (24) is mounted to the outer member (1), and the magnetic sensor (24) faces axially the magnetic encoder (21) with a predetermined gap therebetween.  A gap between the sensor holder (25) and the inner member (2) is sealed by a sealing device (8).  The magnetic encoder (21) is a plastic magnetic encoder.  On either or both of the magnetic encoder (21) and the inner member (2) are formed engaging sections (21ab, 10a) for engaging the magnetic encoder (21) and the inner member (2) with each other to axially restrict the magnetic encoder (21) in position.

Description

Wheel bearing device with rotation detector Related applications

This application claims the priority of Japanese Patent Application No. 2008-193474 filed on July 28, 2008 and Japanese Patent Application No. 2008-207113 filed on August 11, 2008, which is incorporated herein by reference in its entirety. Quote as part.

The present invention relates to a wheel bearing device with a rotation detecting device used for an automobile or the like equipped with an anti-lock brake system.

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

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

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

Therefore, as a solution to such a problem, a wheel bearing device with a rotation detecting device in which the magnetic encoder and the magnetic sensor are installed inside the bearing has also been proposed (for example, Patent Document 1).

JP 2005-300289 A

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, there is a problem that the magnetic encoder easily swells, the magnetic signal is disturbed, and accurate rotation detection cannot be performed. Further, in such a configuration, the axial space becomes large, so it is necessary to make it compact.

In order to meet such a demand, the present inventors have developed a wheel bearing device with a rotation detection device having the configuration shown in FIGS. This wheel bearing device with a rotation detection device includes an axial type plastic magnetic encoder 71 fitted on the outer peripheral surface of an inner member 42 of a bearing serving as a rotating wheel, and an outside of the bearing serving as a fixed wheel with a built-in magnetic sensor 74. An annular sensor holder 75 attached to the side member 41 and a sealing device 48 that seals a space between the sensor holder 75 and the inner member 42 at a position outside the bearing than the plastic magnetic encoder 71. . In the configuration example of FIG. 11, the magnetic sensor 74 is disposed so as to face the plastic magnetic encoder 71 in the axial direction with a predetermined interval at a position inside the bearing relative to the plastic magnetic encoder 71. In the configuration example of FIG. 12, the outer peripheral surface of the plastic magnetic encoder 71 is an inclined surface 71b inclined with respect to the axial direction, and the magnetic sensor 74 is parallel to the inclined surface 71b of the plastic magnetic encoder 71 via a predetermined gap. Arranged to face each other.

In the wheel bearing device with a rotation detection device having the above-described configuration, the plastic magnetic encoder 71 having no slinger is used as the magnetic encoder, so that the size and cost can be reduced.
However, in the case of this configuration, the coupling force of the plastic magnetic encoder 71 to the inner member 42 is higher than that of the rubber magnetic encoder disclosed in Patent Document 1 fitted to the inner member 42 via a slinger. There is a concern that the axial position of the plastic magnetic encoder 71 may be insufficient due to a decrease in the size.

Also in this case, the plastic magnetic encoder is still placed in a high temperature environment near the bearing heat generating part such as a rolling element, and when the automobile is used in a very low temperature region, the plastic magnetic encoder is low in temperature. You will be exposed to the environment. For this reason, the difference in linear expansion coefficient between the plastic magnetic encoder and the metal shaft to which the plastic magnetic encoder is attached causes the plastic magnetic encoder to be easily damaged, causing a problem that the magnetic signal is disturbed, and also cannot accurately detect rotation. The problem remains.

An object of the present invention is to provide a wheel bearing with a rotation detecting device that can be made compact, prevent wear, swelling, damage and displacement of a magnetic encoder, and can be used even in a high and low temperature environment and can detect rotation accurately. Is to provide a device.

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 bearing device for a wheel that includes an inner member serving as a rotation side member and a double row rolling element interposed between the facing rolling surfaces, and rotatably supports the wheel with respect to the vehicle body, A magnetic encoder fitted to and attached to the outer peripheral surface of the inner member and a magnetic sensor are incorporated, and the magnetic sensor is attached to the outer member so as to face the magnetic encoder in the axial direction through a predetermined gap. An annular sensor holder, and a sealing device that seals a space between the sensor holder and the inner member at a position outside the bearing than the magnetic encoder, and the magnetic encoder is a plastic magnetic encoder, This magnetic energy Either or both of the coder and the inner member to form an engagement portion for positional regulation of the magnetic encoder in the axial direction of the both members are engaged with each other.
According to this configuration, the sensor holder with the built-in magnetic sensor is attached to the outer member so that the magnetic sensor faces the magnetic encoder in the axial direction at a predetermined interval, and the sensor holder is positioned outside the bearing relative to the magnetic encoder. A sealing device is provided for sealing a space between the inner member and the inner member. For this reason, it is possible to prevent the magnetic encoder from being worn by foreign matter or the like from the outside. In particular, since a plastic magnetic encoder is used as the magnetic encoder, it is possible to prevent the magnet portion from coming into contact with the grease as the lubricant and swelling. In addition, since either or both of the magnetic encoder and the inner member are engaged with each other to form an engaging portion for restricting the position of the magnetic encoder in the axial direction, the fixing position of the magnetic encoder is set. It can be determined accurately and can be prevented from being displaced due to rotation of the bearing or temperature change. As a result, accurate rotation detection is possible.
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 this invention, the engaging portion is composed of a convex portion formed on the outer peripheral surface of the inner member and a concave portion formed on the inner peripheral surface of the plastic magnetic encoder and engaged with the convex portion. May be. In the case of this configuration, the position of the magnetic encoder in the axial direction can be restricted by an engaging portion with a simple configuration.

In this invention, the engaging portion is composed of a concave portion formed on the outer peripheral surface of the inner member and a convex portion formed on the inner peripheral surface of the plastic magnetic encoder and engaged with the concave portion. Also good. In the case of this configuration, the position of the magnetic encoder in the axial direction can be restricted by an engaging portion with a simple configuration.

In this invention, the engaging portion may be formed of a stepped surface that is formed on the outer peripheral surface of the inner member and engages with a width surface facing the axial direction of the plastic magnetic encoder. In the case of this configuration, the position of the magnetic encoder in the axial direction can be restricted by an engaging portion with a simple configuration.

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

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

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

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

In this invention, the plastic magnetic encoder may be an injection molded product. According to injection molding, plastic magnetic encoders can be easily molded.

In this invention, the plastic magnetic encoder may be a magnetic field formed by injection molding. By forming the magnetic field in this way, a plastic magnetic encoder with a higher magnetic flux density can be obtained.

In this invention, the plastic magnetic encoder has an inclined surface inclined with respect to the axial direction, and the annular sensor holder is opposed to the inclined surface of the plastic magnetic encoder in parallel with a predetermined interval. It may be attached to the outer member.
When the plastic magnetic encoder is configured to face the sensor holder on the inclined surface as described above, the plastic magnetic encoder has a triangular shape in cross section, and thus the plastic magnetic encoder can be reinforced with a compact configuration.

In the present invention, as the magnetic encoder, instead of the plastic magnetic encoder, the magnet to be detected may include a thermoplastic elastomer magnet in which magnetic powder is mixed in a thermoplastic elastomer.
According to this configuration, since the thermoplastic elastomer magnetic encoder is used as the magnetic encoder, unlike the rubber magnetic encoder, it is avoided that the magnet portion swells even when it comes into contact with grease as a lubricant. In addition, the stress inside the magnetic encoder due to the difference in linear expansion coefficient in a high and low temperature environment is smaller than a plastic magnetic encoder and is not cracked if it is a thermoplastic elastomer. As a result, wear, swelling and damage of the magnetic encoder can be prevented and accurate rotation detection is possible.

The present invention will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are merely for illustration and description and should not be used to define the scope of the present invention. The scope of the invention is defined by the appended claims. In the accompanying drawings, the same part number in a plurality of drawings indicates the same part.
1 is a cross-sectional view of a wheel bearing device with a rotation detector according to a first embodiment of the present 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 a 2nd embodiment of this invention. It is a partial expanded sectional view of the wheel bearing apparatus with a rotation detector concerning 3rd Embodiment of this invention. It is a partial expanded sectional view of the wheel bearing apparatus with a rotation detector concerning 4th Embodiment of this invention. It is a partial expanded sectional view of the bearing device for wheels with a rotation detector concerning a 5th embodiment of this invention. FIG. 2 is a wheel bearing device with a rotation detection device according to a first application example of the present invention, and is an enlarged cross-sectional view of a portion corresponding to part A in FIG. 1. 2 is a graph showing the stress-strain behavior of an elastomer compared to other materials such as plastic. It is a partial expanded sectional view of the wheel bearing apparatus with a rotation detection apparatus concerning the 2nd application example of this invention. It is a partial expanded sectional view of a proposal example. It is a partial expanded sectional view of other proposal examples.

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

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

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

FIG. 2 is an enlarged cross-sectional view of part A in FIG. A plastic magnetic encoder 21 is fitted and attached to the inboard side end of the outer peripheral surface of the inner member 2. 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 annular single body, and the inner peripheral surface 21a 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 the inner side of the bearing have a large diameter. It has the inclined surface 21b which is an outer peripheral surface inclined with respect to the axial direction.
The sensor holder 25 is attached to the outer member 1 so that the magnetic sensor 24 faces the inclined surface 21b of the plastic magnetic encoder 21 in parallel with a predetermined interval.

The position of the plastic magnetic encoder 21 is restricted in the axial direction by engaging the inner member 2 with engaging portions 21ab and 10a formed on both the plastic magnetic encoder 21 and the inner member 2. In this case, the engaging portion 10 a of the inner member 2 is a convex portion that extends in the circumferential direction on the outer peripheral surface of the inner ring 10 that is a component of the inner member 2 and is formed in an annular shape. The engaging portion 21ab of the plastic magnetic encoder 21 is a recess that extends in the circumferential direction on the inner peripheral surface 21a and is formed in an annular shape and engages with the engaging portion 10a of the inner member 2. The engaging portions 10a and 21ab may be locally provided at a plurality of locations in the circumferential direction.

As shown in FIG. 3, the plastic magnetic encoder 21 is an annular plastic multipolar magnet that is magnetized in multiple poles so that the magnetic poles N and S are alternately arranged in the circumferential direction. An injection molded product containing a plastic resin is used. The magnetic poles N and S are formed to have a predetermined pitch p in the pitch circle diameter PCD.

If the melt viscosity of the magnetic powder-containing thermoplastic resin that is the material of the plastic magnetic encoder 21 is smaller 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 proportion of the magnetic powder is increased, the kneading failure becomes remarkable. Therefore, in this embodiment, the melt viscosity of the magnetic powder-containing thermoplastic resin is 30 Pa · s or more and 1500 Pa · s or less. Thereby, the plastic magnetic encoder 21 with good productivity can be obtained. Moreover, it leads also to the productivity improvement of the wheel bearing apparatus with a rotation detection apparatus.
The melt viscosity of the thermoplastic resin in this case is a capillograph (manufactured by Toyo Seiki Co., Ltd.), using a capillary with a diameter of 1 mmφ and a land length of 10 mm, a shear rate of 100 (l / s), and a melting point of the thermoplastic resin. The result measured at the temperature of +50 degreeC is shown.

The thermoplastic resin in this case includes polyamide 12, polyamide 612, polyamide 11 and polyphenylene 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. It is preferred to include one or more compounds selected from the group. Since such a thermoplastic resin has poor water absorption, the thermoplastic resin is resistant to deterioration even in a high moisture environment such as dew condensation at low temperatures, salt water, muddy water, rainwater, etc., and the plastic magnetic encoder 21 incorporated in the wheel bearing device is used. It is particularly effective as a material.

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

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

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

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

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

Especially, since the plastic magnetic encoder 21 is used as the magnetic encoder, it is possible to prevent the magnetic encoder from swelling due to contact with grease as a lubricant. In addition, since the plastic magnetic encoder 21 and the inner member 2 are engaged with each other by the engaging portions 21ab and 10a to restrict the position of the plastic magnetic encoder 21 in the axial direction, the plastic magnetic encoder 21 It is possible to accurately determine the fixed position of the shaft, and it is also possible to prevent displacement due to rotation of the bearing, temperature change, or the like. As a result, accurate rotation detection is possible.

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.

Further, in the case of this embodiment, the plastic magnetic encoder 21 has a generally triangular cross section whose outer peripheral surface is an inclined surface 21b inclined with respect to the axial direction, so that the structure of the plastic magnetic encoder 21 can be strengthened. it can.

Further, in place of the plastic magnetic encoder 21 used as the magnetic encoder in the first embodiment, a magnet as a detected portion may be provided with a thermoplastic elastomer magnet in which magnetic powder is mixed in a thermoplastic elastomer. . Thus, when a thermoplastic elastomer magnetic encoder is used as the magnetic encoder, unlike the rubber magnetic encoder, swelling is avoided even when the magnet portion comes into contact with grease as a lubricant. Also, the stress inside the magnetic encoder due to the difference in linear expansion coefficient under a high and low temperature environment is smaller than the plastic magnetic encoder 21 and is not cracked if it is a thermoplastic elastomer. As a result, wear, swelling and damage of the magnetic encoder can be prevented and accurate rotation detection is possible. This thermoplastic elastomer magnetic encoder can be used similarly in the second to fifth embodiments described below, instead of the plastic magnetic encoder 21.

FIG. 4 shows a second embodiment of the present invention. In this embodiment, in the wheel bearing device with a rotation detecting device of the first embodiment shown in FIGS. 1 to 3, the engagement portions 21aa and 10b formed on both the plastic magnetic encoder 21 and the inner member 2 are inward. By engaging with the member 2, the position of the plastic magnetic encoder 21 is restricted in the axial direction. In this case, the engaging portion 10b of the inner member 2 is a concave portion that extends in the circumferential direction on the outer peripheral surface of the inner ring 10 that is a component of the inner member 2, and is formed in an annular shape. The engaging portion 21aa of the plastic magnetic encoder 21 is a convex portion that extends in the circumferential direction on the inner peripheral surface 21a and is formed in an annular shape and engages with the engaging portion 10b of the inner member 2. The engaging portions 10b and 21aa may be provided locally at a plurality of locations in the circumferential direction. Other configurations are the same as those of the first embodiment shown in FIGS.

FIG. 5 shows a third embodiment of the present invention. In this embodiment, in the wheel bearing device with a rotation detector of the first embodiment shown in FIGS. 1 to 3, the plastic magnetic encoder 21 is engaged with the inner member 2 by the engaging portion 10c formed on the inner member 2. As a result, the position of the plastic magnetic encoder 21 is restricted in the axial direction. In this case, the engaging portion 10c of the inner member 2 is formed at the boundary between the large-diameter portion on the inboard side and the small-diameter portion on the outboard side on the outer peripheral surface of the inner ring 10 that is a component of the inner member 2. The step surface is engaged with a width surface facing the inboard side of the plastic magnetic encoder 21 to restrict the displacement of the plastic magnetic encoder 21 toward the inboard side. Other configurations are the same as those of the first embodiment shown in FIGS.

FIG. 6 shows a fourth embodiment of the present invention. In this embodiment, in the wheel bearing device with a rotation detector of the first embodiment shown in FIGS. 1 to 3, the plastic magnetic encoder 21 is engaged with the inner member 2 by the engaging portion 10d formed on the inner member 2. As a result, the position of the plastic magnetic encoder 21 is restricted in the axial direction. In this case, the engaging portion 10d of the inner member 2 is formed at the boundary between the small diameter portion on the inboard side and the large diameter portion on the outboard side on the outer peripheral surface of the inner ring 10 that is a component of the inner member 2. The step surface is engaged with a width surface facing the inboard side of the plastic magnetic encoder 21 to restrict the displacement of the plastic magnetic encoder 21 to the outboard. Other configurations are the same as those of the first embodiment shown in FIGS.

FIG. 7 shows a fifth embodiment of the present invention. In this embodiment, in the wheel bearing device with a rotation detector of the first embodiment shown in FIGS. 1 to 3, the plastic magnetic encoder 21 is engaged with the inner member 2 by the engaging portion 10e formed on the inner member 2. As a result, the position of the plastic magnetic encoder 21 is restricted in the axial direction. In this case, the engaging portion 10e of the inner member 2 is formed between a small-diameter portion in the middle in the axial direction formed on the outer peripheral surface of the inner ring 10 that is a component of the inner member 2, and a large-diameter portion on both sides. It is a stepped surface. The plastic magnetic encoder 21 is fitted into a circumferential groove-shaped portion composed of the small-diameter portion and the engaging portions 10e on the step surfaces on both sides, and the positional deviation is caused in both the outboard side and the inboard side. Is prevented. Other configurations are the same as those of the first embodiment shown in FIGS.

Next, application examples of the present invention will be described. The application example described below is a wheel bearing device with a rotation detection device that can prevent wear, swelling, and damage of the magnetic encoder, and can be strengthened in structure, can be used even in high-temperature environments, and can be made compact. Therefore, the engaging portion for restricting the position of the magnetic encoder in the axial direction in each embodiment of the present invention described above is not a requirement.
First, a first application example will be described with reference to FIG. FIG. 8 is an enlarged cross-sectional view of a portion corresponding to part A in FIG. In this application example, the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
A thermoplastic elastomer magnetic encoder 21A is fitted and attached to the inboard side end of the outer peripheral surface of the inner member 2. An annular sensor holder 25 having a built-in magnetic sensor 24 for detecting the magnetic flux of the thermoplastic elastomer magnetic encoder 21 </ b> A is attached to the inboard side end of the outer member 1. The thermoplastic elastomer magnetic encoder 21A and the magnetic sensor 24 constitute a rotation detection device 20 that detects the rotation of the inner member 2 integrated with the thermoplastic elastomer magnetic encoder 21A, that is, the rotation of the wheel.

The thermoplastic elastomer magnetic encoder 21A has an inner peripheral surface 23a that is press-fitted and fixed to the outer peripheral surface of the inner member 2 (here, the outer peripheral surface of the inner ring 10), and the axial direction so that the inside of the bearing has a large diameter. Thus, a single annular thermoplastic elastomer multipolar magnet 23 having an inclined surface 23b that is an outer peripheral surface inclined outward is formed. The inclined surface 23b is a detected surface. The thermoplastic elastomer multipolar magnet 23 has a sealing device fitting projection 23c that fits on the outer diameter surface of a sealing plate 31 of the sealing device 8 described later at the outer end in the axial direction.
The sensor holder 25 is placed on the outer member 1 so that the magnetic sensor 24 faces the inclined surface 23b of the thermoplastic elastomer magnetic encoder 21A (thermoplastic elastomer multipolar magnet 23) in parallel with a predetermined gap. Mounted.

The description of FIG. 3 described above can be applied to the thermoplastic elastomer multipolar magnet 23 as it is, and the description thereof is omitted.
The thermoplastic elastomer contains one or more compounds selected from the group consisting of ester, urethane, vinyl chloride and olefin. For example, TPO (olefin-based thermoplastic elastomer), TPV (vinyl chloride-based thermoplastic elastomer), TPEE (polyester-based thermoplastic elastomer), or the like can be used as the thermoplastic elastomer.

Regarding the melt viscosity of the magnetic powder-containing thermoplastic elastomer that is the material of the thermoplastic elastomer multipolar magnet 23, the melt viscosity of the magnetic powder-containing thermoplastic resin described in the first embodiment is the same as the reason and advantage described above. The range of 30 Pa · s to 1500 Pa · s is preferable.

In this case, as the thermoplastic elastomer, Hytrel 4767 (manufactured by Toray DuPont Co., Ltd.), which is an ester-based thermoplastic elastomer having a very small amount of swelling even when immersed in grease used as a lubricant in a bearing at high temperature, is used. ), Ferrite powder (FA700 manufactured by Toda Kogyo Co., Ltd.) was added at a volume content of 50 vol% at 220 ° C., and kneaded with a kneader.
Such a thermoplastic elastomer is particularly effective as a material for the thermoplastic elastomer magnetic encoder 21A, which has good oil resistance and is incorporated into a wheel bearing device.

As the magnetic powder that is the material of the thermoplastic elastomer multipolar magnet 23, the same powder as in the case of the plastic magnetic encoder 21 of the first embodiment is used, and the advantages thereof are also the same.

The manufacturing of the thermoplastic elastomer magnetic encoder 21 is the same except that the thermoplastic resin in the description of the manufacturing process of the plastic magnetic encoder 21 of the first embodiment is replaced with the thermoplastic elastomer, and the injection molding is performed. Since the magnetic field shaping at the time and the advantages thereof are the same, detailed description thereof will be omitted.

Since the operation and effect of the wheel bearing device with a rotation detection device having the above-described configuration are the same as those in the first embodiment, detailed description thereof will be omitted.

In particular, since the thermoplastic elastomer magnetic encoder 21A (thermoplastic elastomer multipole magnet 23) is used as the magnetic encoder, unlike the magnetic magnetic encoder, the magnetic encoder can be prevented from coming into contact with the lubricant grease and swelling. . Also, the stress inside the magnetic encoder due to the difference in linear expansion coefficient under a high and low temperature environment is smaller than a plastic magnetic encoder as long as it is a thermoplastic elastomer and does not crack. As a result, wear, swelling, and damage of the magnetic encoder can be prevented and accurate rotation detection can be performed.

When polymer substances are roughly classified, they are divided into resin and elastomer as follows.
(1) Resin-Thermosetting resin: phenol resin, urea resin, etc.-Thermoplastic resin: PP (polypropylene), ABS resin (acrylonitrile butadiene styrene resin), PPS (polyphenylene sulfide), etc. (2) Elastomer-Synthetic rubber, Natural rubber: NBR (nitrile rubber), CR (chloroprene rubber), VMQ (silicone rubber), etc. Thermoplastic elastomer: TPO (olefin), TPVC (vinyl chloride), TPEE (ester), etc. Next, magnetic encoder In order to show that a thermoplastic elastomer is superior as a material, the following will describe data compared with other materials (plastic, elastomer) in terms of its physical properties.
Plastic (thermoplastic resin or thermosetting resin) ............ High hardness and low elastic deformation (within several percent).
Thermoplastic elastomer: It is a polymer material that behaves as a rubber elastic body at room temperature, but melts when the temperature rises. It has both rubber and plastic properties (elastic deformation of about 10%). For this reason, it has flexibility, is moderately stretched and is hard to break.
Elastomer: A flexible (low hardness) elastic body with a large amount of elastic deformation (about several hundred percent). It is a general term for polymer substances (natural rubber, synthetic rubber, etc.) that have very large elasticity at room temperature, and has elongation.
FIG. 9 is a graph showing a comparison of stress-strain behavior of four materials, ie, a thermoplastic resin, polyurethane (thermoplastic elastomer), polyester (thermoplastic elastomer), and elastomer (rubber) as plastics. The graph shows the following.
Plastic: Harder than rubber, large stress during deformation, and small amount of elastic deformation. For this reason, it is easy to break.
Rubber: The elastic deformation is large and it extends sufficiently. Low elastic modulus (Young's modulus).
Thermosetting elastomer: Combines the strength of plastic and the flexibility of rubber. As long as it is used within the range of the strain amount W shown in FIG. 9, the behavior as an elastic body is shown.
Thus, in the case of a thermoplastic elastomer, since the elastic region is wider than that of plastic, it is more resistant to impact and is hard to crack.

FIG. 10 shows a second application example of the present invention. This second application example is the same as the first application example shown in FIG. 8 except that the thermoplastic elastomer magnetic encoder 21A composed of a single unit of the thermoplastic elastomer multipole magnet 23 is replaced with an annular slinger 22 in the wheel bearing device with a rotation detector. This is a thermoplastic elastomer magnetic encoder 21B made of a composite of thermoplastic elastomer multipolar magnets 23. As the thermoplastic elastomer in this case, Hytrel 4767 (manufactured by Toray DuPont Co., Ltd.), which is an ester-based thermoplastic elastomer, is used, and ferrite powder (FA700 manufactured by Toda Kogyo Co., Ltd.) at a volume content of 50 vol% at 220 ° C. It was added and kneaded with a kneader.
A thermoplastic elastomer magnetic encoder 21B molded with this material was incorporated into a bearing and examined for cracks after 800 cycles in a low temperature side -35 ° C and high temperature side 110 ° C heat cycle test (held at each temperature for 1 hour). Cracking did not occur and good high and low temperature characteristics were exhibited. This shows that it can be used even in a sufficiently high and low temperature environment.

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 to the outer diameter side from the inner end of the bearing of the cylindrical portion 22a. It is a cored bar having an annular shape and an L-shaped cross section composed of 22b. The thermoplastic elastomer multipolar magnet 23 is molded separately from the slinger 22 and then bonded to the slinger 22 with a one-component cyanoacrylate adhesive (Toagosei Aron α201) to integrate the heat. A plastic elastomer magnetic encoder 21B is configured. The fact that the outer peripheral surface of the thermoplastic elastomer multipolar magnet 23 is the inclined surface portion 23b is the same as in the previous embodiment. The slinger 22 is made of a magnetic steel plate (SUS430). As described above, by using a magnetic material as the material of the slinger 22, the magnetic force of the thermoplastic elastomer magnetic encoder 21B can be increased as compared with the case of using a non-magnetic material.

The thermoplastic elastomer magnetic encoder 21B in this application example can also be manufactured by insert molding according to the following process. First, the magnetic powder and the molten thermoplastic elastomer are kneaded using a twin screw extruder or a kneader, and the magnetic powder is appropriately dispersed in the thermoplastic elastomer. Thereafter, a thermoplastic elastomer containing magnetic powder is injected into the mold in which the slinger 22 is disposed, and the thermoplastic elastomer multipole magnet 23 is integrally formed with the slinger 22 to obtain a desired thermoplastic elastomer magnetic encoder 21B. The insert molded product of the thermoplastic elastomer magnetic encoder 21B thus obtained is magnetized in multiple poles using a magnetizing yoke, thereby forming the magnetic poles of the thermoplastic elastomer multipole magnet 23. Also in this case, at the time of the injection molding, it is preferable to form a magnetic field while applying a vertical magnetic field of 80000 Oe or more to the inclined surface 23b which is a magnetized surface, and to magnetically orient the contained magnetic powder. Other configurations are the same as those of the first application example shown in FIG. 8, and the description thereof is omitted here.

The application examples that do not require the engaging portions 10a to 10d, 21aa, and 21ab of the present invention described above include the following application modes.

[Aspect 1]
In the wheel bearing device with a rotation detection device according to the aspect 1, the outer member which is a fixed side member with a double row rolling surface formed on the inner periphery, and the rolling surface facing each of the rolling surfaces is on the outer periphery. A wheel bearing device that includes an inner member that is formed as a rotation-side member and a double row rolling element interposed between these opposing rolling surfaces, and that supports the wheel rotatably with respect to the vehicle body, A magnetic encoder that is fitted and attached to the outer peripheral surface near the end of the inner member and is inclined with respect to the axial direction so that the outer peripheral surface faces the end of the inner member, and An annular sensor holder which is attached to the outer member in a fitted state with a cored bar having a built-in magnetic sensor and which faces the inclined surface of the magnetic encoder in parallel via a gap; The sensor holder and the inner member at a position outside the bearing relative to the encoder And a sealing device for sealing the space between, the magnetic encoder, magnets to be detected portion has a thermoplastic elastomer magnetic encoder is a thermoplastic elastomer magnet by mixing magnetic powder into thermoplastic elastomers.
According to this configuration, the detected surface of the magnetic encoder is an outwardly inclined surface, a sensor holder incorporating a magnetic sensor facing the inclined surface is attached to the outer member, and the sealing device is disposed at a position outside the bearing relative to the magnetic encoder. Since it is provided, it is possible to prevent the magnetic encoder from being worn by foreign matters from the outside.
In particular, since a thermoplastic elastomer magnetic encoder is used as the magnetic encoder, unlike the rubber magnetic encoder, swelling is avoided even if the magnet portion comes into contact with grease as a lubricant. In addition, the stress inside the magnetic encoder due to the difference in linear expansion coefficient in a high and low temperature environment is smaller than a plastic magnetic encoder and is not cracked if it is a thermoplastic elastomer. As a result, wear, swelling and damage of the magnetic encoder can be prevented and accurate rotation detection is possible.
In addition, since the magnetic encoder has an inclined surface to be detected, the cross-sectional outline can be made triangular and the structure can be strengthened. Since the detection surface of the magnetic encoder is an inclined surface, the magnetic encoder is disposed at the same axial position as the sensor holder. Therefore, 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.

[Aspect 2]
In the aspect 1, the thermoplastic elastomer magnetic encoder is a multipolar magnet in which the thermoplastic elastomer magnet has magnetic poles arranged in a circumferential direction. The multipolar magnet includes magnetic powder and a thermoplastic resin, and includes the magnetic powder. The melt viscosity of the thermoplastic resin may be 30 Pa · s or more and 1500 Pa · s or less.
When the melt viscosity is less than 30 Pa · s, the magnetic powder-containing thermoplastic elastomer, which is a material for the thermoplastic elastomer multipolar magnet, generates a large amount of burrs during injection molding, making it difficult to mold appropriately. If the melt viscosity of the thermoplastic elastomer is greater than 1500 Pa · s, it becomes difficult to knead the magnetic powder into the thermoplastic elastomer. In particular, when the proportion of the magnetic powder is increased, the kneading failure becomes remarkable. Thus, by setting the melt viscosity of the magnetic powder-containing thermoplastic elastomer to 30 Pa · s or more and 1500 Pa · s or less, a thermoplastic elastomer magnetic encoder with good productivity can be obtained. Further, the productivity improvement of the thermoplastic elastomer magnetic encoder also leads to the improvement of the productivity of the wheel bearing device with the rotation detection device.

[Aspect 3]
In Aspect 2, the thermoplastic elastomer may contain one or more compounds selected from the group consisting of ester, urethane, vinyl chloride and olefin.
Since these thermoplastic elastomers have a very small amount of swelling (less than 10%) even when they are immersed in grease used as a lubricant for bearings at high temperatures, they are materials for thermoplastic elastomer magnetic encoders incorporated in wheel bearing devices. As particularly effective.

[Aspect 4]
In Aspect 2, the magnetic powder may be a ferrite-based magnetic powder. Since ferrite magnetic powder is difficult to oxidize, the corrosion resistance of the thermoplastic elastomer magnetic encoder can be improved.

[Aspect 5]
In Aspect 4, the magnetic powder may be anisotropic ferrite magnetic powder.

[Aspect 6]
In the aspect 1, the thermoplastic elastomer magnet of the thermoplastic elastomer magnetic encoder may be an injection molded product.

[Aspect 7]
In Aspect 6, when the thermoplastic elastomer magnet is an injection-molded product, the thermoplastic elastomer magnet may be formed by magnetic field molding in injection molding. That is, it may be formed by magnetic field molding in an injection mold during injection molding. By forming the magnetic field in this way, a thermoplastic elastomer magnetic encoder having a larger magnetic flux density can be obtained.

[Aspect 8]
In aspect 1, the thermoplastic elastomer magnetic encoder is a single annular thermoplastic elastomer magnet having an inner peripheral surface that is press-fitted and fixed to the outer peripheral surface of the inner member and an outer peripheral surface that is the inclined surface. May be.
Thus, if a thermoplastic elastomer magnetic encoder is constituted by a single thermoplastic elastomer magnet having no slinger, the cost of the thermoplastic elastomer magnetic encoder can be reduced.

[Aspect 9]
In the aspect 1, the thermoplastic elastomer magnetic encoder includes a cylindrical portion that is press-fitted and fixed to the outer peripheral surface of the inner member, and a slinger having an L-shaped cross section that includes a standing plate portion that rises from one end portion of the cylindrical portion. The slinger may be formed of a thermoplastic elastomer magnet having an outer peripheral surface integrally formed over the cylindrical portion and the standing plate portion of the slinger.

[Aspect 10]
In Aspect 9, the thermoplastic elastomer magnetic encoder having the slinger is an insert-molded product in which the thermoplastic elastomer magnet is integrally molded by injecting a magnetic powder-containing thermoplastic elastomer into a mold in which the slinger is disposed. Also good. Alternatively, a slinger and a thermoplastic elastomer magnet may be manufactured separately, and a thermoplastic elastomer magnetic encoder having the slinger integrated by bonding them together may be used.
As an adhesive at this time, an isocyanate, urethane, ester, vinyl chloride, rubber, or cyanoacrylate adhesive can be used. In particular, urethane type and cyanoacrylate type are preferable.

[Aspect 11]
In the aspect 10, in the injection molding of the thermoplastic elastomer magnetic encoder, when the thermoplastic elastomer magnet is integrally formed with the slinger by an insert method, the slinger material is preferably a nonmagnetic material. By using a non-magnetic material as a material for the slinger, the magnetic powder distribution in the thermoplastic elastomer magnetic encoder is improved compared to the case where a magnetic material is used, so that the magnetic force can be increased.
In addition, by producing a slinger and a thermoplastic elastomer magnet separately, and bonding and integrating them, when a thermoplastic elastomer magnetic encoder having a slinger is used, by using a magnetic material as a slinger material, Compared with the case of using a nonmagnetic material, the magnetic force can be increased.

As described above, the preferred embodiments have been described with reference to the drawings. However, those skilled in the art will readily assume various changes and modifications within the obvious scope by looking at the present specification. Accordingly, such changes and modifications are to be construed as within the scope of the invention as defined by the appended claims.

DESCRIPTION OF SYMBOLS 1 ... Outer member 2 ... Inner member 3, 4 ... Rolling surface 5 ... Rolling body 8 ... Sealing device 10a-10d, 21aa, 21ab ... Engagement part 20 ... Rotation detection device 21 ... Plastic magnetic encoder 21A, 21B ... Thermoplastic elastomer magnetic encoder 22 ... Slinger 22a ... Cylindrical portion 22b ... Standing plate portion 23 ... Thermoplastic elastomer multipolar magnet 23a ... Inner peripheral surface 23b ... Inclined surface 24 ... Magnetic sensor 25 ... Sensor holder

Claims (12)

1. 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 double-row rolling element interposed between the rolling surfaces, and a wheel bearing device for rotatably supporting the wheel with respect to the vehicle body,
   A magnetic encoder fitted to and attached to the outer peripheral surface of the inner member and a magnetic sensor are incorporated, and the magnetic sensor is attached to the outer member so as to face the magnetic encoder in the axial direction through a predetermined gap. An annular sensor holder, and a sealing device that seals a space between the sensor holder and the inner member at a position outside the bearing than the magnetic encoder,
   The magnetic encoder is a plastic magnetic encoder, and one or both of the magnetic encoder and the inner member are engaged with each other to form an engaging portion that restricts the position of the magnetic encoder in the axial direction. A wheel bearing device with a rotation detection device.
2. 2. The rotation detection according to claim 1, wherein the engaging portion includes a convex portion formed on an outer peripheral surface of the inner member and a concave portion formed on an inner peripheral surface of the plastic magnetic encoder and engaged with the convex portion. Wheel bearing device with device.
3. The rotation detection device according to claim 1, wherein the engaging portion includes a concave portion formed on the outer peripheral surface of the inner member and a convex portion formed on the inner peripheral surface of the plastic magnetic encoder and engaged with the concave portion. Wheel bearing device with attached wheels.
4. 2. The wheel bearing device with a rotation detecting device according to claim 1, wherein the engaging portion includes a stepped surface that is formed on an outer peripheral surface of the inner member and engages a width surface facing an axial direction of the plastic magnetic encoder.
5. 2. The magnetic encoder according to claim 1, wherein the plastic magnetic encoder is a magnetic encoder having a multipolar magnet in which magnetic poles are arranged in a circumferential direction, and the multipolar magnet includes magnetic powder and a thermoplastic resin. A wheel bearing device with a rotation detector having a melt viscosity of 30 Pa · s to 1500 Pa · s.
6. 6. The wheel bearing device with a rotation detecting device according to claim 5, wherein the thermoplastic resin includes one or more compounds selected from the group consisting of polyamide 12, polyamide 612, polyamide 11, and polyphenylene sulfide.
7. 6. The wheel bearing device with a rotation detector according to claim 5, wherein the magnetic powder is a ferrite magnetic powder.
8. The wheel bearing device with a rotation detector according to claim 7, wherein the magnetic powder is an anisotropic ferrite magnetic powder.
9. The wheel bearing device with a rotation detecting device according to claim 1, wherein the plastic magnetic encoder is an injection molded product.
10. 10. The wheel bearing device with a rotation detector according to claim 9, wherein the plastic magnetic encoder is formed by magnetic field molding in injection molding.
11. 2. The plastic magnetic encoder according to claim 1, wherein the plastic magnetic encoder has an inclined surface inclined with respect to an axial direction, and the annular sensor holder faces the inclined surface of the plastic magnetic encoder in parallel with a predetermined interval. A wheel bearing device with a rotation detection device mounted on the outer member.
12. 2. The wheel bearing device with a rotation detecting device according to claim 1, wherein, as the magnetic encoder, instead of a plastic magnetic encoder, a magnet serving as a detected portion includes a thermoplastic elastomer magnet in which magnetic powder is mixed in a thermoplastic elastomer.

Images