JP2007163320A - Magnetic encoder and rolling bearing unit provided with the magnetic encoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic encoder for improving reliability by preventing foreign matters from leaking from a fitting part to a rotating body of a slinger, and to provide a rolling bearing unit provided with the magnetic encoder. <P>SOLUTION: The magnetic encoder 14 comprises a slinger 17 having a cylinder part 15 fitted to the inner ring 13 of a rolling bearing 10, and a magnet 18 formed into a form of circular ring, multi-pole magnetized in the circumferential direction and contacted on the slinger 17 being concentric with the inner ring 13. The magnetic encoder 14 forms an elastic coat 20 on the fitted face of the inner ring 13 in the cylinder part 15 of the slinger 17. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a magnetic encoder used for detecting the number of rotations of a rotating body and a rolling bearing unit including the magnetic encoder.

  Conventionally, in an automobile, anti-skid to prevent skid (a phenomenon in which the wheel slips in a substantially stopped state) and traction control to effectively transmit the driving force to the road surface (unnecessary idling of the driving wheel, which is likely to occur when starting or accelerating) For example, the number of rotations of the wheel is detected. In detecting the number of rotations of a wheel, a number of rotation number detection devices in which a magnetic pulse generated by a magnetic encoder attached to a rotating wheel of a bearing is detected by a sensor is often used.

  FIG. 6 shows an example of a conventional rotational speed detection device (see, for example, Patent Document 1). This rotational speed detection device is externally fixed to an inner ring 101b in a rolling bearing including an outer ring 101a and an inner ring 101b that is rotatable by interposing a plurality of rolling elements (not shown) between the outer ring 101a. The magnetic encoder 105 is formed by joining an annular magnet 104 to a slinger 103, and the sensor 106 is disposed so as to face the magnet 104 in the axial direction. The seal member 102 fitted and fixed to the outer ring 101a causes the lip 102a to slidably contact the slinger 103, thereby causing leakage of grease inside the bearing, intrusion of moisture or foreign matter into the bearing from the outside, and the like. Is prevented.

  The rotational speed of the inner ring 101b is detected by sensing a magnetic pulse generated by the magnet 104 of the magnetic encoder 105 by means of a sensor 106 disposed opposite to the magnet 104 in the axial direction.

  The magnet 104 of the magnetic encoder 105 is made of an elastic magnetic material in which magnetic powder is mixed with an elastic material such as rubber or resin, and is pressed on the outer surface in the axial direction of the flange portion 103a of the slinger 103 coated with an adhesive. Modeled and joined to the flange portion 103a.

  As the elastic magnetic material, a nitrile rubber containing ferrite is generally used, and the magnetic powder is mechanically oriented by being kneaded by a roll. As the adhesive, resol type phenolic resin adhesive is generally used in consideration of vulcanization adhesion with rubber magnets. In some cases, phenolic resin adhesive is highly epoxy resin with high water resistance. There are also examples in which these are mixed, and these adhesives are used as top coat adhesives, and silane coupling agents and epoxy resins are combined as undercoat adhesives to improve water resistance.

JP 2001-255337 A

  The surface of the slinger 103 to which an adhesive is applied for joining to the magnet 104 is finally covered with a hardened adhesive film of about several μm, but the slinger 103 is used as the inner ring 101b. The adhesive coating on the inner peripheral surface of the slinger 103 peels off when fitted with interference, and in a normal mounting state, it is almost between the inner peripheral surface of the slinger 103 and the outer peripheral surface of the inner ring 101b. There is nothing intervening. In this case, when rust or the like is generated on the inner peripheral surface of the slinger 103 and the outer peripheral surface of the inner ring 101b due to the aging of the bearing, the gap between the inner peripheral surface of the slinger 103 and the outer peripheral surface of the inner ring 101b in the fitted state is increased. There is a possibility that a minute gap may occur, and there is a possibility that moisture may enter the bearing from the gap.

  The present invention has been made in order to eliminate such inconveniences, and an object of the present invention is to prevent foreign matters from entering from a fitting portion of the slinger with respect to the rotating body and improve reliability. An object of the present invention is to provide a magnetic encoder that can be used and a rolling bearing unit including the magnetic encoder.

  The above object is achieved by a rolling bearing unit including the following magnetic encoders (1) to (3) and the magnetic encoder (4) below according to the present invention.

(1) A slinger having a fitting portion to be fitted to the rotating body, and a magnet formed in an annular shape and multipolarly magnetized in the circumferential direction, and concentrically bonded to the slinger. A magnetic encoder, wherein an elastic film is formed on a fitting surface of the fitting portion of the slinger with the rotating body.
(2) The elastic coating is a curable phenol resin, curable epoxy resin, amorphous fluororesin, curable urethane resin, curable acrylic resin, curable polyurea resin, polyparaxylylene derivative, acrylic rubber, acrylonitrile butadiene. The magnetic encoder according to (1) above, comprising at least one selected from the group consisting of rubber, hydrogenated acrylonitrile butadiene rubber, fluorine rubber, and silicon rubber.
(3) The magnetic encoder according to (1) or (2), wherein the magnet is made of a plastic magnet material containing magnetic powder and a thermoplastic resin as a binder of the magnetic powder.
(4) A rolling bearing unit comprising a fixed wheel, a rotating wheel disposed concentrically with a plurality of rolling elements interposed between the rotating wheel, and a magnetic encoder attached to the rotating wheel. And the said magnetic encoder is a magnetic encoder as described in any one of said (1)-(3), The rolling bearing unit characterized by the above-mentioned.

Hereinafter, the magnetic encoder of the present invention will be described in detail.
The material of the magnet of the magnetic encoder of the present invention is not particularly limited, but considering the bonding property to the slinger, a magnet compound containing about 50 to 80% by volume of magnetic powder and using a thermoplastic resin or rubber as a binder is suitable. Can be used. As the magnetic powder, ferrite such as strontium ferrite and barium ferrite, rare earth magnetic powder such as neodymium-iron-boron, samarium-cobalt, samarium-iron can be used, and lanthanum is used to improve the magnetic properties of ferrite. It may be a mixture of rare earth elements such as. When the content of the magnetic powder is less than 50% by volume, the magnetic properties are inferior, and it becomes difficult to perform multipolar magnetization in the circumferential direction at a fine pitch, which is not preferable. On the other hand, when the content of the magnetic powder exceeds 80% by volume, the binder amount becomes too small, the strength of the whole magnet is lowered, and at the same time, molding becomes difficult and practicality is lowered.

  When a thermoplastic resin is used as the binder, those that can be injection-molded are suitable. Specifically, a hard segment made of polyamide 6, polyamide 12, polyamide 612, polyamide 11, polyphenylene sulfide (PPS), polyamide 12 and Modified polyamide 12 comprising a soft segment comprising a polyether chain or a polyester chain, a modified polyester comprising a hard segment comprising a polyester such as polybutylene terephthalate or polybutylene naphthalate and a soft segment comprising a polyether chain or a polyester chain, etc. Can be used. In addition, since there is a possibility that calcium chloride used as a snow melting agent may be splashed with water on the magnet of the magnetic encoder, polyamide 12, polyamide 612, polyamide 11, polyphenylene sulfide (PPS), modified polyamide with low water absorption 12, modified polyester is more preferred. Furthermore, in order to prevent cracks due to sudden temperature changes (thermal shock) assumed in the environment where the magnetic encoder is used, the modified polyamide 12, modified polyester, or modified which improves bending flexibility and crack resistance by adding. Most preferably, a mixture of polyamide 12 and polyamide 12 or a mixture of modified polyester and polyester resin is used.

  When rubber is used as the binder, nitrile rubber, acrylic rubber, hydrogenated nitrile rubber, fluorine rubber, etc. having both oil resistance and heat resistance are suitable.

  As the magnetic powder, ferrite is most suitable in consideration of cost and oxidation resistance. However, when rare earths are used with priority given to magnetic properties, the oxidation resistance is lower than that of ferrite. In order to maintain stable magnetic properties over the surface, a surface treatment layer such as electric or electroless nickel plating, epoxy resin coating, silicon resin coating, or fluororesin coating may be provided on the exposed magnet surface.

  As the material of the slinger, ferritic stainless steel (SUS430, etc.), martensitic stainless steel (SUS410, etc.), etc. that do not deteriorate the magnetic properties of the magnet material and have a certain level or more of corrosion resistance depending on the usage environment. In addition, magnetic materials such as high corrosion resistance ferritic stainless steel such as SUS434 and SUS444, which are further improved in corrosion resistance by adding Mo or the like, are preferable.

  In order to improve the bonding force with the adhesive, the bonding surface with the slinger magnet used in the present invention is preferably provided with fine irregularities. As a method of providing the unevenness, in addition to mechanical methods such as shot blasting and transfer of unevenness on the mold surface during press molding, the surface once surface-treated may be chemically etched with acid or the like. . When unevenness is provided on the magnet bonding surface, an adhesive enters the magnetic bonding surface, and the bonding force between the magnet and the slinger is strengthened by the anchor effect.

  The adhesive used for joining the slinger and the magnet is in a semi-cured state to the extent that it will not be detached and washed away by the molten high-pressure plastic magnet material or rubber magnet material fluid at the time of magnet insert molding, It is preferable that the resin is completely cured by heat from the molten resin / fluid rubber or in addition to secondary heating after molding. Adhesives that can be used can be diluted with a solvent, and phenol resin adhesives, epoxy resin adhesives, etc., which proceed with a curing reaction close to two stages, take into account heat resistance, chemical resistance, and handling properties. It is preferable.

  The elastic coating of the magnetic encoder of the present invention comprises a curable phenol resin, a curable epoxy resin, an amorphous fluororesin, a curable urethane resin, a curable acrylic resin, a curable polyurea resin, a polyparaxylylene derivative, an acrylic resin. It consists of at least one selected from the group of rubber, acrylonitrile butadiene rubber, hydrogenated acrylonitrile butadiene rubber, fluorine rubber, and silicon rubber. Among these, an amorphous fluororesin film having a water repellency in the material itself and a polyparaxylylene derivative are particularly preferable because they have an effect of suppressing the permeation of moisture.

  Amorphous fluororesin is a polymer having a fluorine-containing aliphatic ether ring structure in the main chain, and specifically, a monomer composed of alkenyl vinyl ether such as perfluoro (allyl vinyl ether) or perfluoro (butenyl vinyl ether). Is obtained by copolymerizing these monomers with a radically polymerizable monomer such as tetrafluoroethylene, chlorotrifluoroethylene, perfluoro (methyl vinyl ether) or the like. The amorphous fluororesin preferably has a structure in which a functional group such as a carboxyl group is introduced at the end or the like in order to improve the adhesion to the substrate. Since this amorphous fluororesin has a property of being dissolved in a perfluoro solvent such as perfluoro (2-butyltetrahydrofuran), when a film is actually formed on the surface of the slinger, 1 to 10 It can be performed by dipping in a solution in which about% by weight is dissolved and then drying.

  The film thickness of the elastic coating depends on the solution concentration, and the concentration is adjusted appropriately so as to obtain a desired thickness. The film thickness of the elastic coating for maintaining sufficient sealing performance is 5 to 100 μm, preferably 10 to 50 μm. When the film thickness is less than 5 μm, the amount of elastic deformation is too small, and the effect of contributing to improvement of the sealing property is small, which is not preferable. On the other hand, if the film thickness exceeds 100 μm, the effect of improving the sealing property is not changed, and it is difficult to make the film thickness uniform, resulting in an increase in cost. In order to improve the adhesion (adhesion) between the elastic film and the fitting surface of the slinger, it is more preferable to perform a heat treatment at about 100 to 120 ° C. for about 0.5 to 3 hours or a primer treatment. is there.

  A curable urethane resin, a curable acrylic resin, a curable epoxy resin, and a curable polyurea resin have functional groups that are cured by heat, ultraviolet (UV), moisture, and the like in the structure. The film thickness is similar to that of amorphous fluororesin. The curable urethane resin, curable acrylic resin, curable epoxy resin, and curable polyurea resin are used for the adhesive cured film mainly composed of phenol resin, etc., provided on the slinger surface for adhesion to the magnet. Can also be formed directly on the surface of the slinger or on the cured adhesive film. The thickness of the coating is 5 to 100 μm, preferably 10 to 50 μm, equivalent to the amorphous fluororesin.

  The polyparaxylylene derivative is represented by the following chemical formula (1), and is formed by chemical vapor deposition of a (2,2) -paracyclophane compound represented by the chemical formula (2). In both chemical formulas (1) and (2), X1 and X2 represent hydrogen, lower alkyl, or halogen elements such as chlorine, and X1 and X2 may be the same or different.

  Specific examples of the chemical formula (1) are polyparaxylylene, polymonochloroparaxylylene, polydichloroparaxylylene, etc., and the heat resistance is higher for those with many chlorine substituents. Assuming the temperature, polymonochloroparaxylylene having a normal maximum use temperature of about 120 ° C. and polydichlorobaraxylylene having a temperature of about 150 ° C. are more suitable.

  In addition, the polyparaxylylene derivative represented by the chemical formula (1) may have a chemical structure represented by the following chemical formula (3) in which hydrogen is partially fluorinated to improve heat resistance. In addition, the usual maximum use temperature of the film of the chemical formula (3) is very high at about 250 ° C.

  The film thickness of the polyparaxylylene derivative film is preferably the same as described above. However, in order to increase the film thickness, the processing cost by the chemical vapor deposition method is increased, and about 5 to 10 μm is appropriate.

  When forming a rubber-based film of acrylic rubber, acrylonitrile butadiene rubber, hydrogenated acrylonitrile butadiene rubber, fluorine rubber, or silicon rubber, the rubber material alone does not have adhesiveness to the slinger, so the adhesive layer It is necessary to provide. As the adhesive, although depending on the state of the rubber to be coated, when using an unvulcanized rubber, it is preferable to use a vulcanized adhesive suitable for each rubber material. When vulcanized rubber is used, the adhesive is not particularly limited as long as it can be bonded. However, since vulcanized rubber is inferior in ductility and malleability and difficult to coat with a thin film, considering the processability, unvulcanized rubber is more suitable for the rubber before coating. There is an optimum method in which vulcanization and adhesion are simultaneously advanced by heat during coating to form a tough film.

  The thickness of the rubber-based film is 10 to 200 μm, more preferably 20 to 100 μm, including the thickness of the adhesive layer. When the thickness is less than 10 μm, the thickness of the rubber film excluding the adhesive layer is too thin, so that the amount of elastic deformation is small, the effect of improving the sealing property is not so much improved, and the practicality is low. On the other hand, when the thickness exceeds 200 μm, the rubber layer becomes thick, which increases the possibility of breaking at the rubber layer when press-fitted into the rotating body, which is not preferable.

  When the magnet material is a plastic magnet material using a thermoplastic resin as a binder, the plastic magnet material melted from the inner diameter thickness part flows into the mold at a high pressure at the same time, and is rapidly cooled and solidified in the mold. The disk gate type or similar ring gate type injection molding is preferred. In these methods, the molten magnet material spreads in a disk shape and then flows into the mold corresponding to the inner diameter thick portion, so that the flake-like magnetic powder contained therein is oriented parallel to the surface. To do. In particular, the portion between the inner peripheral portion and the outer peripheral portion serving as the detection surface of the sensor has a higher orientation, and is in a state very close to the axial anisotropy oriented in the thickness direction. Further, when a magnetic field is applied to the mold in the thickness direction during molding, the anisotropy becomes closer to perfection. Even when magnetic field molding is performed, if the gate is other than a disk gate, for example, a pin gate, the orientation at the weld is completely anisotropic in the process of gradually increasing the resin viscosity toward solidification. Therefore, it is difficult to cause cracks or the like to occur in the weld portion where the magnetic properties are lowered and the mechanical strength is lowered.

  When the magnet material is a rubber magnet material, the molding is preferably a disk gate type as in the case of a plastic magnet if the molding is performed by injection molding. If compression molding is used, first place a slinger in the mold (lower mold), then cover the sheet with an unvulcanized rubber magnet and the mold (upper mold) for vulcanization adhesion. It is molded by doing.

  According to the present invention, since the elastic film is formed on the fitting surface of the fitting part of the slinger fitted to the rotating body, the elastic film is interposed between the rotating body and the fitting part of the slinger, Intrusion of foreign matter from the fitting portion can be prevented, and reliability can be improved.

(First embodiment)
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view of a magnetic encoder and a rolling bearing unit including the magnetic encoder according to a first embodiment of the present invention, FIG. 2 is a perspective view of a single unit of the magnetic encoder of FIG. 1, and FIG. It is sectional drawing of the other rolling bearing unit provided.

  As shown in FIG. 1, the magnetic encoder 14 of this embodiment includes a rolling bearing including an outer ring 11 and an inner ring 13 that is rotatable with a plurality of rolling elements (not shown) interposed between the outer ring 11 and the outer ring 11. 10, it is attached to the end of the inner ring 13.

  The magnetic encoder 14 includes a cylindrical portion 15 that is fitted on the outer peripheral surface of the end portion of the inner ring 13, a slinger 17 having a flange portion 16 that extends radially outward from the axial end portion of the cylindrical portion 15, and a shaft of the flange portion 16. And a magnet 18 joined to the outer surface in the direction through an adhesive, and in the vicinity of the magnet 18, a sensor 19 is disposed opposite to the axial direction. And the elastic film 20 which is the principal part of this invention is formed in the internal peripheral surface which is a fitting surface with respect to the inner ring | wheel 13 of the cylindrical part 15 of the slinger 17. As shown in FIG.

  The lip 21 of the seal member 12 that is fitted and fixed to the outer ring 11 of the rolling bearing 10 is in sliding contact with the inner side surface in the axial direction of the slinger 17. The slinger 17 and the seal member 12 constitute a bearing sealing device, and the sealing device prevents entry of foreign matters such as dust into the bearing inner space and leakage of the lubricant to the outside of the bearing.

  As shown in FIG. 2, the magnet 18 of the magnetic encoder 14 is formed in an annular shape, and S poles and N poles are alternately magnetized at equal intervals in the circumferential direction (that is, multipolar). The number of poles is about 70 to 130, preferably 90 to 120. If the number of poles is less than 70, the number of poles is too small and it is difficult to accurately detect the rotational speed. On the other hand, when the number of poles exceeds 130, each pitch becomes too small, and it is difficult to suppress a single pitch error, and practicality is low.

  The magnetic encoder 14 rotates together with the inner ring 13 and periodically changes the magnetic flux density at a point near the magnet 18 with a peak number corresponding to the number of poles while the inner ring 13 rotates once (in other words, , Generate magnetic pulses). This change in magnetic flux density is detected by the sensor 19 so that the number of rotations of the inner ring 13 is detected.

  The magnetic encoder 14 is not limited to the rolling bearing 10 described above, and can be applied to a hub unit that supports wheels in a vehicle such as an automobile.

  A hub unit 30 shown in FIG. 3 rotatably supports a wheel (not shown) fastened to a mounting flange 35 of the hub 34, and is provided between an outer ring 31 fixed to a vehicle body (not shown) and the outer ring 31. And a hub 34 that is rotatable by interposing a plurality of rolling elements 33 in two rows, and an inner ring member 32 that is caulked and fixed to an axial end of the hub 34 on the vehicle body side. Between the outer ring 31 and the inner ring member 32, the magnetic encoder 14 is fitted and fixed to the inner ring member 32, and the seal member 12 is fitted and fixed to the outer ring 31.

  The magnetic encoder 14 rotates together with the inner ring member 32 and the hub 34, and has a peak number corresponding to the number of poles of the magnetic flux density at a point near the magnet 18 of the encoder 11 while the inner ring member 32 and the hub 34 rotate once. Change periodically. The change in the magnetic flux density is detected by the sensor 19, and the rotational speeds of the inner ring member 32 and the hub 34 (that is, the wheels) are detected.

  As described above, in the magnetic encoder 14 of the present embodiment, the magnet portion 18 made of an injection-moldable plastic magnet material having a resin binder is bonded to the axially outer surface of the flange portion 16 of the slinger 17 via an adhesive. On the inner peripheral surface that is a fitting surface of the cylindrical portion 15 of the slinger 17 with respect to the inner ring member 32, an elastic coating 20 that is a main part of the present invention is formed.

  The magnet 18 is joined to the flange portion 16 of the slinger 17 by previously holding the slinger 17 in which a thermosetting adhesive containing at least one of a phenolic resin and an epoxy resin is applied in a semi-cured state in a mold. The molten magnet material is bonded to the flange portion 16 of the slinger 17 by injection molding (insert molding) of the plastic magnet material with a disk gate in a state where a magnetic field is applied in the thickness direction. In this case, insert molding is performed in a state where a semi-cured film of the adhesive is applied, and heat in the mold at the time of molding is performed, and further secondary heating is performed as necessary, so that the flange portion of the magnet 18 and the slinger 17 16 is firmly joined.

  Here, when the resin-based elastic coating 20 is formed on the inner peripheral surface of the cylindrical portion 15 of the slinger 17, the inner peripheral surface of the cylindrical portion 15 was diluted with a solvent after the magnet 18 was joined to the flange portion 16. A film-forming resin is applied and the surface is dried, and then the film is completely cured by heat or ultraviolet rays. When the elastic coating 20 is formed by dipping or chemical vapor deposition (polyparaxylylene derivative), a method of performing masking or the like on other portions of the magnet 18 and slinger 17 is appropriate.

  When the rubber-based elastic coating 20 is formed on the inner peripheral surface of the cylindrical portion 15 of the slinger 17, first, an unvulcanized thin rubber sheet is semi-cured on the heated molding die. The plastic magnet material is injection-molded (insert molding) in the state of being set together with the slinger 17 covered with, and the slinger 17, the magnet 18, and the rubber sheet (elastic coating 20) are joined. Furthermore, by performing secondary heating as necessary, the bonding force becomes stronger. The rubber sheet is sandwiched between the slinger 17 and the mold member in the molding die, and is molded to a desired thickness.

  As described above, in this embodiment, the elastic coating 20 is formed on the fitting surface of the cylindrical portion 15 of the slinger 17 that is fitted to the inner ring 13 of the rolling bearing 10 that is a rotating body or the inner ring member 32 of the hub unit 30. Therefore, the elastic coating 20 is interposed between the inner ring 13 and the cylindrical portion 15 of the slinger 17 so that foreign matter can be prevented from entering from the fitting portion of the cylindrical portion 15 and the reliability can be improved. be able to.

(Second Embodiment)
Next, with reference to FIG. 4 and FIG. 5, the rotational speed detection apparatus with a seal provided with the magnetic encoder which is the 2nd Embodiment of this invention is demonstrated.
FIG. 4 is a cross-sectional view of a magnetic encoder and a rolling bearing unit including the magnetic encoder according to a second embodiment of the present invention, and FIG. 5 is a single perspective view of the magnetic encoder of FIG.

  As shown in FIG. 4, the magnetic encoder 44 of the present embodiment is a rolling bearing that includes an outer ring 41 and an inner ring 43 that is rotatable with a plurality of rolling elements (not shown) interposed between the outer ring 41 and the outer ring 41. At 40, it is attached to the end of the inner ring 43.

  The magnetic encoder 44 includes a cylindrical portion 45 fitted on the outer peripheral surface of the end portion of the inner ring 43, a flange portion 46a extending radially outward from the axial end portion of the cylindrical portion 45, and a diameter from the outer peripheral end of the flange portion 46a. A slinger 47 having a bent portion 46b bent inward in the direction and a cylindrical portion 46c extending outward in the axial direction from the inner peripheral end of the bent portion 46b, and an outer peripheral surface of the cylindrical portion 46c are bonded to each other with an adhesive. A magnet 49 is provided, and a sensor 49 is disposed in the vicinity of the magnet 48 so as to face the radial direction. The elastic coating 20 that is the main part of the present invention is formed on the inner peripheral surface that is the fitting surface of the cylindrical portion 45 of the slinger 47 with respect to the inner ring 43, similar to the magnetic encoder 14 of the first embodiment described above. Yes.

  A lip 42 a of a seal member 42 fitted and fixed to the outer ring 41 of the rolling bearing 40 is in sliding contact with the axially inner surface of the slinger 47. The slinger 47 and the seal member 42 constitute a bearing sealing device, and the sealing device prevents entry of foreign matters such as dust into the bearing internal space and leakage of the lubricant to the outside of the bearing.

  As shown in FIG. 5, the magnet 48 of the magnetic encoder 44 is formed in an annular shape, and S poles and N poles are alternately magnetized at equal intervals in the circumferential direction (that is, multipolar). Here, in the present embodiment, in order to enable detection of the rotation speed and the axial load, the boundary line between the S pole and the N pole is, for example, an inverted V shape (or a C shape). Magnetized.

  The magnetic encoder 44 rotates together with the inner ring 43 and periodically changes the magnetic flux density at a point near the magnet portion 48 of the encoder 44 with a peak number corresponding to the number of poles while the inner ring 43 makes one rotation ( In other words, a magnetic pulse is generated). This change in magnetic flux density is detected by a sensor 49 to detect the rotational speed of the inner ring 43.

  Here, in this embodiment, as shown in FIG. 4, two sensors 49A and 49B are spaced apart in the axial direction, and act on the bearing from the phase difference of the pulses detected by the sensors 49A and 49B, respectively. The load in the axial direction is also detected. About another structure and an effect, it is the same as that of the said 1st Embodiment.

  Note that the configurations of the rotating body, cylindrical portion, slinger, adhesive, magnet portion, elastic coating, fixed ring, rotating ring, rolling element, etc. of the present invention are not limited to the above-described embodiment, and the gist of the present invention As long as it does not deviate from the above, it can be changed as appropriate.

  For example, in the above-described embodiment, the case where the rotating wheel is the inner ring and the magnetic encoder is attached to the inner ring is illustrated. Alternatively, the rotating wheel may be the outer ring and the magnetic encoder may be attached to the outer ring. .

Hereinafter, actual application examples of the material and forming method of the magnet 18 (48) of the magnetic encoder, the material of the slinger 17 (47), and the elastic coating 20 in the first and second embodiments described above will be described.
(Material of magnet)
Toda Kogyo Strontium Ferrite-containing 12 Nylon Anisotropic Plastic Magnet Compound “FEROTOP (registered trademark) TP-A27N” (Strontium Ferrite Content 75% by Volume): Maximum Energy Product: 2.1MGoe by Magnetic Field Molding It was. The thickness of the magnet 18 (48) was 0.9 mm.
(Magnet forming method)
A magnetic field was applied in the thickness direction during molding, and the disk gate method was used. When the mold was cooled, reversal demagnetization was performed, and the magnet was completely demagnetized. Then, along with the magnetized yoke, N and S were alternately magnetized to 96 poles. In order to cure the adhesive completely, it was heated at 150 ° C. for 1 hour.
(Slinger material)
SUS430 having a thickness of t = 0.6 mm was used as a base material, N0.2B finishing (about Ra0.06) was performed, and only the joint surface with the magnet was set to Ra0.75 by shot blasting.
(adhesive)
A 30% solid content phenol resin adhesive (metal lock (registered trademark) N-15 manufactured by Toyo Chemical Laboratories) with a novolak-type phenol resin as the main component was further diluted 3-fold with methyl ethyl ketone, and the slinger was treated by immersion treatment. Applied to the surface. Then, after drying at room temperature for 30 minutes, it was made into the semi-hardened state by leaving it to stand in 120 degreeC for 30 minutes.
(Elastic coating)
After coating the coating liquid (Furatan (registered trademark) 535, manufactured by Futsura Tech Sales Co., Ltd.) with a solid content of curable polyurethane elastomer as the main component to the fitting surface of the slinger fitting portion with a brush. And cured completely at room temperature for 3 hours. The thickness of the elastic coating was about 50 μm.

A water spray test was performed on the magnetic encoder of the example having the above-described configuration and a magnetic encoder having the same shape and no elastic coating as a comparative example while being press-fitted into the shaft.
(Water spray test)
Water spray amount: 4 cm ³ / min
Water spray pressure: 0.2 MPa
Water spray cycle: 5 seconds spray, 5 seconds stop Shaft rotation speed: 1000 min ⁻¹
Spraying time: 5000 hours Spraying position: Near the inner diameter press-fitting part (fitting part)

  As a result of the water spray test, when water intrusion after 5000 hours was observed, water intrusion was observed in the comparative example, whereas water intrusion was observed in the example. There wasn't.

It is sectional drawing of the rolling bearing unit provided with the magnetic encoder which is 1st Embodiment of this invention, and the said magnetic encoder. It is a single-piece | unit perspective view of the magnetic encoder of FIG. Sectional drawing of the other rolling bearing unit provided with the magnetic encoder of FIG. It is sectional drawing of the rolling bearing unit provided with the magnetic encoder which is 2nd Embodiment of this invention, and the said magnetic encoder. It is a single-piece | unit perspective view of the magnetic encoder of FIG. It is principal part sectional drawing which shows an example of the conventional rotation speed detection apparatus.

Explanation of symbols

10 Rolling bearing 11 Outer ring (fixed ring)
13 Inner ring (Rotating wheel)
14 Magnetic encoder 15 Cylindrical part (fitting part)
17 Slinger 18 Magnet 20 Elastic coating

Claims (4)

A slinger having a fitting portion to be fitted to the rotating body;
A magnet formed in an annular shape and multipolarly magnetized in the circumferential direction, concentrically with the rotating body and joined to the slinger;
A magnetic encoder comprising:
A magnetic encoder, wherein an elastic film is formed on a fitting surface of the slinger at the fitting portion with the rotating body.   The elastic coating is composed of curable phenol resin, curable epoxy resin, amorphous fluororesin, curable urethane resin, curable acrylic resin, curable polyurea resin, polyparaxylylene derivative, acrylic rubber, acrylonitrile butadiene rubber, hydrogen. 2. The magnetic encoder according to claim 1, comprising at least one selected from the group consisting of added acrylonitrile butadiene rubber, fluorine rubber, and silicon rubber.   The magnetic encoder according to claim 1 or 2, wherein the magnet is made of a plastic magnet material containing magnetic powder and a thermoplastic resin as a binder of the magnetic powder. A fixed ring,
A rotating wheel disposed concentrically with a plurality of rolling elements interposed between the rotating wheel, and
A magnetic encoder attached to the rotating wheel;
A rolling bearing unit comprising:
The said magnetic encoder is a magnetic encoder as described in any one of Claims 1-3, The rolling bearing unit characterized by the above-mentioned.

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