JP2003035565A - Magnetic encoder and bearing for wheel employing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic encoder for detecting the rotation of a bearing for wheel, which enables the wall to be thinned and has superior resistance to abrasion and superior productivity. SOLUTION: The magnetic encoder 10 is composed of a metallic annular member 11 and a magnetic member 14 disposed along the surface of the annular member 11 in the circumferential direction. A coating film of a synthetic coating resin, in which magnetic fine particles are mixed, is used as the magnetic member 14. The magnetic member 14 is magnetized so as to form multiple poles in the circumferential direction, and magnetic poles N, S are formed alternately. The magnetic encoder 10 is also used as a thrower of the bearing for wheel or the like, for example.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic encoder used in a rotation detecting device for a bearing that rotates relative to each other, and a wheel bearing equipped with the magnetic encoder. The present invention relates to a magnetic encoder that is a component of a bearing seal mounted on a rotation detection device that detects a magnetic field.

[0002]

2. Description of the Related Art Conventionally, the following structure has been widely used as an anti-skid rotation detecting device for preventing skid of an automobile. That is, the rotation detecting device comprises a toothed rotor and a sensor,
It is general that the bearings are arranged separately from the seal device that seals the bearings to form one independent rotation detection device. Such a conventional example has a structure in which a toothed rotor fitted to a rotating shaft is detected and detected by a rotation detecting sensor attached to a knuckle, and a bearing used is provided independently on its side portion. The sealing device protects against the ingress of moisture or foreign matter.

As another example, Japanese Patent Publication No. 281678.
In No. 3, in order to reduce the installation space of the rotation detection device and dramatically improve the sensing performance, the diameter of the slinger used in the bearing seal equipped with the rotation detection device for wheel rotation detection A structure in which elastic members mixed with magnetic powder in the direction are vulcanization-molded and bonded in a circumferential shape, and magnetic poles are alternately arranged therein is shown. In addition, in Kokaihei 6-281018, the axial dimension is reduced,
For the purpose of improving the airtightness between the rotating member and the fixed member and enabling easy attachment, the rotating member and the fixed member are sealed, and the rotating disk is attached to the rotating member. It is shown that the disk has a coder built-in hermetically sealed structure in which a multipolar coder is attached. The coder used is made of an elastomer to which magnetic particles are added, and the side surface of the coder is a sealing means which is substantially flush with the side surface of the fixing member.

A coder made of a magnetic powder or a plastic (plastomer) containing magnetic particles can be shaped by using a mold adapted to the product shape, like conventional injection molding and compression molding. In other words, it is molded into the shape of the mold, or the sheet is formed by sheet molding such as extrusion molding using a T-shaped die or calender molding, and punched to form the product shape. You may manufacture it by adhering and fixing it with the. Further, in this case, the metal substrate may be assembled in advance in the mold as in the insert molding, and then the molten resin may be poured into the mold to simultaneously process the bonding process.

[0005]

However, among the above-mentioned conventional examples, Japanese Patent Publication No. 2816783 and Japanese Unexamined Patent Publication No.
In the bearing seal shown in No. 281018, an elastic member mixed with magnetic powder in the radial direction of a slinger to be used is vulcanized and bonded in a circumferential shape, or a multipolar coder is attached to a built-in coder. If an attempt is made to use an elastomer containing magnetic particles as the coder as a closed structure, an elastomer or elastic member component serving as a binder for holding the magnetic powder or magnetic particles is required. However, when an elastomer or elastic member component is used as a binder, a dispersion process by kneading the magnetic powder or magnetic particles with the elastomer or elastic member is always required before shaping into a coder shape. In this process, the binder component in the coder is used. Since it is difficult to increase the relative content (volume fraction) of the magnetic powder or the magnetic particles with respect to, it was necessary to increase the thickness of the coder in order to obtain a magnetic force that is stably sensed by the magnetic sensor.

Further, the molding of the elastic member containing magnetic powder or magnetic particles or the coder made of elastomer is performed by using a mold suitable for the product shape such as injection molding or compression molding. If a vulcanization step is required, it must be held under pressure for the vulcanization time required in the mold, which required many steps in production. Further, the magnetic powder or the elastic member or the coder made of elastomer containing the magnetic particles can reduce the installation space of the rotation detecting device and improve the sensing performance in a bearing seal having a rotation detecting device for detecting the wheel rotation, for example. In order to dramatically improve,
Sensing sensors must be placed at locations close to and opposite to each other in the axial direction of the slinger used. However, in this case, when foreign matter particles such as sand particles enter and are caught in the gap between the bearing seal surface on the rotating side and the surface of the sensing sensor on the stationary side while the vehicle is running, the elastic member and the surface of the coder made of elastomer may be worn. Severe damage was sometimes noted.

In the case of a coder made of a magnetic powder or a plastic (plastomer) containing magnetic particles, the above-mentioned conventional injection molding, compression molding, sheet molding such as extrusion molding using a T-shaped die or calender molding, and When it is attempted to manufacture by insert molding, a synthetic resin component serving as a binder for holding magnetic powder or magnetic particles is also required. However, even when a synthetic resin component is used as a binder, a dispersion step by kneading magnetic powder or magnetic particles with a plastomer or an elastic member is always required before shaping into a coder shape, as in the case of conventional elastomers. After all, in this process, it is difficult to increase the relative content (volume fraction) of the magnetic powder or the magnetic particles with respect to the binder component in the coder. It was necessary to increase the thickness dimension. In addition, the pre-molding material produced by kneading the magnetic powder or magnetic particles with the plastomer or the elastic member in this way by the conventional manufacturing method is injected (compression) or compressed (compression) in the mold to be a coder. At the time of shaping, or at the time of shaping by insert molding, etc., the magnetic particle component contained in the material is an oxide of metal, so it is hard and the wear of the mold and the molding machine becomes a problem in mass production, Further, the material before molding having a high content of the magnetic particle component has a high melt viscosity, and there is a problem that the molding load is increased, such as the molding pressure and the mold clamping force are increased.

Even in the case of sheet molding such as extrusion molding or calender molding using a T-shaped die, the magnetic particle component contained in the material is a metal oxide and is hard. The abrasion of the roll of the molding machine became a problem.

An object of the present invention is to provide a magnetic encoder which can be made thin and which is excellent in wear resistance and productivity. Another object of the present invention is to detect rotation with a compact configuration without increasing the number of parts,
Another object of the present invention is to provide a wheel bearing having excellent durability of a magnetic encoder for detecting rotation.

[0010]

A magnetic encoder according to the present invention is a magnetic encoder comprising a metallic annular member and a magnetic member provided along the circumferential direction of the annular member and magnetized to have multiple poles in the circumferential direction. In the encoder, the magnetic member is made of synthetic resin paint mixed with magnetic powder.

The above synthetic resin coating material comprises a coating film forming main element and
It may contain a solvent or a diluent. The synthetic resin coating material may be a powder coating material in which at least the main film-forming element is powder. The coating film forming main element of the synthetic resin paint may be made of an epoxy resin.
The coating film forming main element of the synthetic resin paint may be made of an acrylic resin. The magnetic powder mixed in the synthetic resin paint may be made of a ferrite magnetic material. The magnetic powder mixed in the synthetic resin paint may be made of a rare earth magnetic material.

The magnetic encoder of this structure is used for rotation detection by making a magnetic sensor face a magnetic member. When this magnetic encoder is rotated, the passage of each magnetic pole magnetized into multiple poles of the magnetic member is detected by the magnetic sensor, and the rotation is detected in the form of a pulse. Since the magnetic member is made of a synthetic resin paint mixed with magnetic powder, as shown below,
The thickness of the magnetic encoder can be reduced while securing a magnetic force that can provide stable sensing, and the magnetic encoder can be made compact, and it is also excellent in wear resistance and productivity.

That is, the coating material in which the magnetic powder is mixed with the synthetic resin component as the binder is dispersed in the solvent while adjusting the composition ratio of the powder of the resin component and the magnetic powder, or the dry powder type powder is used. Since the particles can be mixed and dispersed, the relative content (volume fraction) of the magnetic powder or the magnetic particles in the coating film can be increased. Therefore, a magnetic force that is stably sensed by the magnetic sensor can be easily obtained, and it is not necessary to increase the magnetic film thickness of the magnetic member. Also, in the production of magnetic materials made of magnetic powder or paint films containing magnetic particles, synthetic resin (plastomer), which is classified as a polymer substance that is completely different from elastomer, is used as the binder, so heating / pressurizing hold The vulcanization step to perform is unnecessary. Therefore, the production process can be overwhelmingly simplified as compared with the case where the elastomer is used as the binder. A general coating method may be used to form the paint film that will become the magnetic member, and the mold used for injection molding or compression molding for shaping with an elastomer or plastomer is not required, and damage caused by abrasion of the mold etc. And the problem of molding load can be completely avoided.

The wheel bearing of the present invention is a seal for sealing an inner member and an outer member, a double row rolling element accommodated between these inner and outer members, and an end annular space between the inner and outer members. In a bearing for a wheel including a device, the magnetic encoder having any one of the above configurations of the present invention is a constituent element of the sealing device. According to the wheel bearing of this configuration, since the constituent element of the sealing device is the magnetic encoder, the rotation of the wheel can be detected without increasing the number of parts. Wheel bearings are generally exposed to the environment of the road surface, and particles such as sand particles may get caught between the magnetic encoder and the magnetic sensor facing it. Be protected like. That is, the surface hardness of the magnetic member, which is a coder made of a coating film containing a large amount of magnetic powder or magnetic particles, is harder than that of a conventional elastic member containing magnetic powder or magnetic particles or an coder made of elastomer. Therefore, in a bearing seal device having a magnetic encoder for wheel rotation detection, particles such as sand particles are caught in the gap between the surface of the bearing seal device on the rotating side and the surface of the magnetic sensor on the stationary side while the vehicle is traveling. Even if it is rare, it has a great effect of reducing wear damage on the surface of the magnetic member.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the magnetic encoder 10 includes an annular member 11 made of metal, and a magnetic member 14 provided on the surface of the annular member 11 along the circumferential direction. The magnetic member 14 is magnetized to have multiple poles in the circumferential direction, and magnetic poles N and S are alternately formed. The magnetic poles N and S are formed to have a predetermined pitch p in the pitch circle diameter PCD (FIG. 2). This magnetic encoder 10 is
It is attached to a rotating member (not shown) and is used for rotation detection by facing the magnetic sensor 15 to the magnetic member 14 as shown in FIG. 3, and the rotation detecting device is composed of the magnetic encoder 10 and the magnetic sensor 15. 20 are configured. This figure shows an application example in which the magnetic encoder 10 is a constituent element of a seal device 5 for a bearing (not shown).
It is attached to the bearing ring on the rotating side of the bearing. Sealing device 5
Is composed of a magnetic encoder 10 and a fixed-side seal member 9. The specific configuration of the sealing device 5 will be described later.

The magnetic encoder 10 includes a magnetic member 14
Is a synthetic resin paint mixed with magnetic powder.
The magnetic poles N and S are magnetized after the coating film of the synthetic resin paint is formed. The synthetic resin coating material of the magnetic member 14 may include a coating film forming main element and a solvent or a diluent.
A typical paint contains a film-forming main component and a solvent or diluent. Further, in the synthetic resin coating material of the magnetic member 14, at least the coating film forming main element may be powder.

The terms of the "paint" and its components as used in this specification will be explained. The paint comprises a film-forming element and a film-forming auxiliary element. The coating film forming element is a coating film forming main element and a coating film forming sub-element provided as necessary for this,
And a pigment. The film-forming main component is a main component of the film, and is often an organic polymer. Film-forming subelement refers to a substance added to aid in the formation of a film and to improve performance. These include plasticizers, desiccants, hardeners, dispersants, anti-skin agents, thickeners, leveling agents, anti-sagging agents, mildew-proofing agents, UV absorbers and the like. Pigments are used to color and impart opacity to the coating and to reinforce the mechanical properties of the coating. The coating film formation assisting element refers to a volatile component such as a solvent and a diluent.

The synthetic resin as the main component for forming a coating film in the synthetic resin coating material of the magnetic member 14 is a phenol resin coating material (alcohol-soluble phenol resin coating material, oil-soluble phenol resin coating material, cashew resin coating material, alkyd resin coating material, aminoalkyd). Resin coating (melamine resin, urea resin, benzoguanamine resin alone or mixed), vinyl resin coating (vinyl chloride resin coating, butyral resin coating, styrene-butadiene resin coating, vinyl sol resin coating), chlorinated rubber coating, epoxy resin coating (epoxy / Phenolic resin paint, Epoxy / Amino resin paint, Epoxy / Alkyd / Melamine resin paint, Epoxy alkyd resin paint, Baking epoxy ester paint, Room temperature dry epoxy ester paint, Amine curing epoxy paint, Epoxy coal tar paint, Epoxy dye Cyanate paint), acrylic resin paint (thermoplastic acrylic resin paint, thermosetting acrylic resin paint), unsaturated polyester resin paint, polyurethane resin paint (oil-modified polyurethane resin paint, moisture curable polyurethane resin paint, block type polyurethane resin paint) , Polyol curable polyurethane resin paint, urethane resin type UV curable paint), Silicone resin paint (pure silicone resin paint, alkyd modified silicone resin paint, polyester modified silicone resin paint, acrylic modified silicone resin paint, epoxy modified silicone resin paint), Fluororesin paint can be used.

Further, as the synthetic resin coating material for the magnetic member 14, thermoplastic powder coating material, thermosetting powder coating material and the like can be used. As the thermoplastic powder coating material, a thermoplastic resin such as polyethylene, vinyl chloride or nylon may be used. Thermosetting powder coatings include epoxy type, epoxy / polyester type, polyester / urethane type,
A thermosetting powder coating such as acrylic may be used. The powder coating material is a coating material which does not contain a solvent for the purpose of forming a coating film. More specifically, the powder coating material is a coating material in which all of the coating film forming main element, the coating film forming sub-element, and the pigment are powders and do not contain a coating film forming auxiliary element as a volatile component such as a solvent or a diluent. That is. There is also a so-called "solvent-free paint", which is a paint that does not require a solvent because the coating film forming main element itself is liquid. Magnetic member 1
A solventless paint may be used as the synthetic resin paint of No. 4, but this is different from the above powder paint.

As the magnetic powder mixed in the synthetic resin paint of the magnetic member 14, a ferrite magnetic material such as barium ferrite or strontium ferrite, or a rare earth magnetic material such as samarium iron nitrogen or neodymium iron boron is used. You can

The metal used as the material of the annular member 11 is preferably a magnetic material, particularly a metal which is a ferromagnetic material. For example, a steel sheet which is magnetic and has anticorrosive properties is used. As such a steel plate, a ferritic stainless steel plate (JIS standard SUS430 series or the like) or a rust-prevented rolled steel plate can be used.

The shape of the annular member 11 can be various annular shapes, but the groove portion 11 in which the magnetic member 14 is formed is formed.
A shape with b is preferred. As shown in FIG. 1, for example, the annular member 11 has an annular shape having an L-shaped cross section, which includes a cylindrical portion 11a and a standing plate portion 11b extending from one end thereof to the outer diameter side. The cylindrical portion 11a and the standing plate portion 11b are integrally press-molded. The standing plate portion 11b is formed in a groove shape, and the magnetic member 14 is formed in the groove portion 11ba. The groove portion 11ba is directed outward.

The magnetic member 14 is formed on the annular member 11 by coating such as coating and baking, and then magnetized. For example, the magnetic member 14 is formed by applying a synthetic resin paint containing magnetic powder and a solvent to the groove 11ba of the annular member 11, air-drying the solvent, and then baking the paint to form the magnetic member 14 made of a paint film. According to the prototype, a synthetic resin paint containing magnetic powder was applied and air-dried. The surface of the magnetic member 14 made of a paint film formed by baking is
A very smooth surface having a free surface was formed as a general coating film.

In addition to the method described above, the magnetic member 14 is formed by pouring powder coating material composed of magnetic powder and synthetic resin into the groove portion 11ba of the annular member 11 and then baking it to form the magnetic member 14 made of a coating film. Also good. The surface of the magnetic member 14 made of a paint film formed by incorporating a powder coating composed of magnetic powder and synthetic resin by trial production and then baking it is a general coating film, and is a very smooth surface having a free surface. Was formed.

As described above with reference to FIG. 3, the magnetic encoder 10 having this structure is used for rotation detection by making the magnetic sensor 15 face the magnetic member 14. Magnetic encoder 10
When is rotated, the magnetic sensor 15 detects the passage of the magnetic poles N and S magnetized in the multipole of the magnetic member 14, and the rotation is detected in the form of a pulse. The pitch p (FIG. 2) of the magnetic poles N and S can be set finely. For example, the pitch p can be 1.5 mm and the difference between the pitches can be ± 3%, which enables highly accurate rotation detection. Magnetic encoder 10
3 is applied to the bearing seal device 5 as shown in FIG. 3, the rotation of the bearing to which the magnetic encoder 10 is attached is detected. Since the magnetic member 14 is made of a synthetic resin paint mixed with magnetic powder, as shown below, the magnetic member 14 can be made thin while ensuring a magnetic force that enables stable sensing, and the magnetic encoder 10 can be made compact. It has excellent wear resistance and productivity.

That is, the coating material in which the magnetic powder is mixed with the synthetic resin component as the binder is dispersed in the solvent while adjusting the composition ratio of the powder of the resin component and the magnetic powder, or the dry type powder is used. Since the particles can be mixed and dispersed, the relative content (volume fraction) of the magnetic powder or the magnetic particles in the coating film can be increased. Therefore, a magnetic force that is stably sensed by the magnetic sensor 15 can be easily obtained, and the magnetic member 1
There is no need to increase the magnetic coating thickness of No. 4. Further, in the production of the magnetic member 14 made of a coating film containing magnetic powder or magnetic particles, as described in, for example, Iwanami Physics and Chemistry Dictionary, 4th edition (published by Iwanami Shoten Co., Ltd.), it is apparent that an elastomer is used. Since a synthetic resin (plastomer), which is classified as a completely different polymer, is used as a binder, the vulcanization process of heating and pressurizing is unnecessary. Therefore, the production process can be overwhelmingly simplified as compared with the case where the elastomer is used as the binder. The coating film to be the magnetic member 14 may be formed by a general coating method, and a mold used for injection molding or compression molding for shaping with an elastomer or a plastomer is unnecessary, and damage due to abrasion of the mold or the like becomes unnecessary. Problems and molding load problems can be completely avoided. Further, the surface hardness of the magnetic member 14 made of a coating film containing a high amount of magnetic powder or magnetic particles is
Harder than conventional magnetic powder and elastic members containing magnetic particles and coder made of elastomer. Therefore, when applied to the rotation detecting device 20 for detecting wheel rotation, particles such as sand particles are caught in the gap between the surface of the rotating magnetic member 14 and the surface of the fixed magnetic sensor 15 while the vehicle is traveling. Even if it occurs, the magnetic member 14 is less likely to be worn and damaged, and has a significant effect of reducing wear as compared with a conventional elastic member.

Next, an example of a wheel bearing including the magnetic encoder 10 and an example of the seal device 5 will be described.
This will be described with reference to FIGS. As shown in FIG. 5, this wheel bearing includes an inner member 1 and an outer member 2, a plurality of rolling elements 3 housed between the inner and outer members 1 and 2, and a member between the inner and outer members 1 and 2. And 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. Inner member 1
The outer member 2 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. Even if the bearing inner ring and the bearing outer ring are independent, these bearing inner rings are used. It may also be an assembly member in which the bearing outer ring and another component are combined. Further, the inner member 1 may be a shaft. The rolling elements 3 are balls or rollers, and balls are 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 has a pair of raceway surfaces 1a, 1a of each rolling element row. It is composed of split type inner rings 18, 19. These inner rings 18 and 19 are fitted to the outer periphery of the shaft portion of the hub wheel 6 and constitute the inner member 1 together with the hub wheel 6. The inner member 1 has the hub ring 6 and one inner ring 18 integrated instead of the three-part assembly of the hub ring 6 and the pair of split type inner rings 18 and 19 as described above. It may be composed of two parts including a hub wheel with a raceway surface and the other inner ring 19.

One end (for example, an outer ring) of a constant velocity universal joint 7 is connected to the hub wheel 6, and a wheel (not shown) is attached to a flange portion 6a of the hub wheel 6 with a bolt 8. The constant velocity universal joint 7 has the other end (for example, an inner ring) 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 in a suspension device. The rolling elements 3 are held by the cage 4 for each row.

FIG. 4 shows an enlarged view of the sealing device 5 with a magnetic encoder. In this sealing device 5, the magnetic encoder 10 serves as a slinger, and the inner member 1 and the outer member 2
Is attached to the member on the rotation side. In this example, since the member on the rotation side is the inner member 1, the magnetic encoder 1
0 is attached to the inner member 1. The seal device 5 will be described in detail. The seal device 5 has annular members 11 and 12 made of first and second metal plates attached to the inner member 1 and the outer member 2, respectively. These annular members 11 and 12 are attached by being fitted into the inner member 1 and the outer member 2 in a press-fitted state. Both annular members 11 and 12 are cylindrical parts 11 respectively.
a and 12a and standing plate portions 11b and 12b are formed in an L-shaped cross section and face each other. The first annular member 11 is
The inner member 1 and the outer member 2 are fitted to the inner member 1, which is a member on the rotation side, to form a slinger. The first annular member 11 is an annular member in the magnetic encoder 10. By arranging the magnetic sensor 15 facing the magnetic member 14 in the magnetic encoder 10 as shown in the figure, the rotation detecting device 20 for detecting the wheel rotation speed is configured.

The second annular member 12 is the seal member 9 described above.
(FIG. 3), the side lip 16a slidingly contacting the standing plate portion 11b of the first annular member 11 and the cylindrical portion 1
It integrally has radial lips 16b and 16c which are in sliding contact with 1a. These lips 16a to 16c are provided as a part of the elastic member 16 vulcanized and bonded to the second annular member 12. The number of these lips 16a to 16c may be arbitrary, but in the example of FIG. 4, one side lip 16a is used.
And two radial lips 16 located inside and outside in the axial direction
c and 16b are provided. The second annular member 12 has an elastic member 16 held in a fitting portion with the outer member 2 which is a fixed member. That is, the elastic member 16 is
It is assumed to have 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.
Intervenes in the fitting portion between the second annular member 12 and the outer member 2.

The cylindrical portion 12a of the second annular member 12 and the first
The end face of the standing plate portion 11b of the annular member 11 is faced with a slight radial gap, and the labyrinth seal 1
Make up 7.

According to the wheel bearing having this structure, the rotation of the inner member 1 rotating with the wheel is transmitted to the magnetic sensor 15 via the magnetic encoder 10 attached to the inner member 1.
And the wheel rotation speed is detected. Since the magnetic encoder 10 is a constituent element of the sealing device 5, it is possible to detect the rotation of the wheel without increasing the number of parts. The wheel bearing is generally exposed to the environment of the road surface, and particles such as sand particles may be caught between the magnetic encoder 10 and the magnetic sensor facing this.
As described above, since the magnetic member 14 of the magnetic encoder 10 is made of synthetic resin paint and is hard, abrasion damage on the surface of the magnetic member 14 is significantly reduced as compared with the conventional elastic member. . Further, the space at the bearing end portion of the wheel bearing 5 is a limited narrow space due to the constant velocity joint 7 and the bearing support member (not shown) in the periphery, but the magnetic member 14 of the magnetic encoder 10 is the above-mentioned space. Since the thickness can be reduced as described above, the rotation detecting device 20 can be easily arranged. Regarding the seal between the inner and outer members 1 and 2, the second annular member 1
2. The sliding contact of each of the seal lips 16a to 16c provided at 2 and the tip of the standing plate portion 11b of the first annular member 11 faces the cylindrical portion 12a of the second annular member 12 with a slight radial gap. And a labyrinth seal 17 composed of

In the above embodiment, the annular member 11 of the magnetic encoder 10 is made of a steel plate press-molded product. However, as shown in FIG. 6, the annular member 11 of the magnetic encoder 10 is a machined product of steel or the like. May consist of The annular member 11 in the example of the figure is the groove portion 11 of the standing plate portion 11b.
Ba is used as a cutting groove. Also, the magnetic encoder 1
In the case where 0 is a constituent element of the bearing seal device 5, the magnetic member 14 may be provided inwardly with respect to the bearing, contrary to the above embodiments. In that case, the annular member 11 is preferably made of a non-magnetic material. Further, the magnetic encoder 10 has the same structure as the magnetic member 1 as in the above embodiments.
4 is not limited to the one oriented in the axial direction, but may be provided in the radial direction as shown in FIG. 7, for example. In the example of the figure, a second cylindrical portion 11c extending axially outward from an annular member 11 serving as a slinger of the sealing device 5 is provided, and the second cylindrical portion 1 is provided.
A magnetic member 14 is provided on the outer periphery of 1c. In this case, the magnetic sensor 15 is arranged facing the magnetic member 14 in the radial direction.

Further, the magnetic encoder of the present invention is not limited to the component of the bearing seal device 5 and can be used independently for rotation detection. For example, the magnetic encoder 10 in the embodiment of FIG. 1 may be provided on the bearing separately from the seal device 5, and as shown in FIG. 8, the magnetic encoder 10 in which the magnetic member 14 is oriented in the radial direction has a cylindrical annular shape. The magnetic member 14 may be provided on the outer diameter surface of the member 11 and may be fitted to the outer diameter surface of the outer member 2A in the wheel bearing. In the wheel bearing shown in the figure, the outer member 2A of the inner member 1A and the outer member 2A is a member on the rotation side, and the wheel mounting flange 26 is provided on the outer member 2A. The sealing device 14 is the magnetic encoder 1.
The bearing is provided separately from 0. The outer member 2A is composed of a pair of split inner rings 18A and 19A.

[0036]

The magnetic encoder of the present invention is a magnetic encoder provided with a metallic annular member and a magnetic member provided along the circumferential direction on the annular member and magnetized in the circumferential direction with multiple poles. Since the magnetic member is made of synthetic resin paint mixed with magnetic powder, it can be made thinner while ensuring a magnetic force that can provide stable sensing, and the magnetic encoder can be made compact and has excellent wear resistance. Will be things. Moreover, since the magnetic member to be the coder portion can be manufactured by a simple coating process, the production process can be greatly simplified as compared with the conventional elastomer or elastic member using the coder. The wheel bearing of the present invention comprises an inner member and an outer member, a double row rolling element accommodated between these inner and outer members, and a seal device for sealing an end annular space between the inner and outer members. In the wheel bearing provided, since the magnetic encoder of the present invention is used as a constituent element of the sealing device, rotation detection can be performed in a compact configuration without increasing the number of parts, and the durability of the magnetic encoder for rotation detection is excellent. It becomes a thing.

[Brief description of drawings]

FIG. 1 is a partial perspective view of a magnetic encoder according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of magnetic poles showing the magnetic encoder from the front.

FIG. 3 is a partially cutaway front view showing a sealing device including the magnetic encoder and a magnetic sensor.

FIG. 4 is a partial cross-sectional view of a wheel bearing provided with the same sealing device.

FIG. 5 is an overall cross-sectional view of the wheel bearing.

FIG. 6 is a partial perspective view of a magnetic encoder according to another embodiment of the present invention.

FIG. 7 is a partial cross-sectional view of a wheel bearing including a magnetic encoder according to another embodiment of the present invention.

FIG. 8 is a partial sectional view of a wheel bearing including a magnetic encoder according to still another embodiment of the present invention.

[Explanation of symbols]

1 ... Inner member 2 ... Outer member 1A ... Inner member 2A ... Outer member 3 ... rolling elements 5 ... Sealing device 10 ... Magnetic encoder 11 ... Annular member 14 ... Magnetic member 15 ... Magnetic sensor 20 ... Rotation detection device

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G01P 3/487 G01P 3/487 FL

Claims (8)

[Claims] 1. A magnetic encoder comprising a metallic annular member and a magnetic member provided along the circumferential direction of the annular member and magnetized to have multiple poles in the circumferential direction, wherein the magnetic member is magnetic powder. A magnetic encoder characterized by being made of a synthetic resin paint mixed with. 2. The magnetic encoder according to claim 1, wherein the synthetic resin coating material contains a film forming main element and a solvent or a diluent. 3. The magnetic encoder according to claim 1, wherein the synthetic resin paint is a powder paint in which at least a film forming main element is powder. 4. The magnetic encoder according to claim 2, wherein the main component for forming a coating film of the synthetic resin coating material is an epoxy resin. 5. The magnetic encoder according to claim 2, wherein the main component for forming a coating film of the synthetic resin paint is made of acrylic resin. 6. The magnetic encoder according to claim 1, wherein the magnetic powder mixed in the synthetic resin paint is made of a ferrite magnetic material. 7. The magnetic encoder according to claim 1, wherein the magnetic powder mixed in the synthetic resin paint is made of a rare earth magnetic material. 8. A wheel having an inner member and an outer member, a double row rolling element accommodated between these inner and outer members, and a seal device for sealing an end annular space between the inner and outer members. A bearing for a wheel, wherein the magnetic encoder according to any one of claims 1 to 7 is a component of the sealing device.