JP4432764B2 - Manufacturing method of magnetic encoder and manufacturing method of rolling bearing unit for supporting wheel - Google Patents

Description

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

  Conventionally, anti-skid to prevent car skid (a phenomenon in which the wheel slips in a substantially stopped state) or traction control to effectively transmit the driving force to the road surface (unnecessary idling of the driving wheel that is likely to occur at the time of start and acceleration) As a rotation speed detection device used for control, etc., there are an annular encoder in which N poles and S poles are alternately magnetized in the circumferential direction, and a sensor for detecting a change in the magnetic field in the vicinity of the encoder. It is also known that an encoder is provided alongside a sealing device for sealing a bearing that supports a wheel so that the encoder rotates together with the rotation of the wheel, and a magnetic field change synchronized with the rotation of the wheel is detected by a sensor. (For example, refer to Patent Documents 1 and 2.)

  As shown in FIG. 8, the rotational speed detection device with a seal described in Patent Document 1 is attached to a seal member 102 attached to the outer ring 101a, a slinger 103 fitted to the inner ring 101b, and an outer surface of the slinger 103. The encoder 104 is configured to generate a magnetic pulse, and the sensor 105 is disposed adjacent to the encoder 104 to detect the magnetic pulse. In the bearing unit to which this rotational speed detector with seal is attached, the seal member 102 and the slinger 103 prevent foreign matters such as dust from entering the inside of the bearing, and the lubricant filled in the bearing is external to the bearing. To prevent leakage. The encoder 104 generates the number of magnetic pulses corresponding to the number of poles during one rotation of the inner ring 101b, and detects the number of rotations of the inner ring 101b by detecting this magnetic pulse with the sensor 105.

Conventionally, an elastic magnetic material obtained by mixing magnetic powder into an elastic material such as rubber or resin is used for a magnetic encoder used for a wheel bearing. Since the encoder made of magnetic rubber is suitably joined to the slinger by vulcanization adhesion, it absorbs the thermal expansion difference from the slinger generated under a severe temperature environment (−40 ° C. to 120 ° C.) by its elastic deformation. be able to. For this reason, the adhesiveness to the slinger is maintained even in the temperature environment as described above, and the problem of peeling hardly occurs. Generally, a nitrile rubber containing ferrite is used as a magnetic powder for an encoder, and the magnetic powder is mechanically oriented by being kneaded with a roll. .
JP 2001-255337 A JP 2003-57070 A

  In recent years, in order to more accurately detect the rotation speed of the wheel, the magnet portion of the magnetic encoder tends to be further multipolar in the circumferential direction. However, in the conventional rubber magnet containing ferrite powder by the mechanical orientation method, the magnetic flux density per pole becomes small, and in order to accurately detect the rotation speed, a gap (that is, an air gap) between the sensor and the magnet is required. Since it is necessary to make it small, assembly may be difficult. For this reason, it was necessary to improve the magnetic characteristics of the magnet in order to increase the air gap from the viewpoint of ease of assembly. However, when the mixing amount of the magnetic powder is increased in order to improve the magnetic characteristics, the elasticity of the rubber magnet is lowered, so that excellent thermal shock resistance is remarkably impaired. For this reason, since the absorption effect of the thermal expansion difference between the rubber magnet and the slinger is impaired, the rubber magnet may be peeled off from the slinger.

  On the other hand, a plastic magnet in which magnetic powder is mixed with plastic can mix a relatively large amount of magnetic powder with a rubber magnet. In this respect, the encoder material has a magnetic property superior to that of a rubber magnet. Have the potential to become. Furthermore, the plastic magnet is easy to be injection-molded (magnetic field molding) in a state where a magnetic field is applied, whereby an anisotropic magnet indispensable for exhibiting excellent magnetic properties can be obtained.

  However, since plastic magnets cannot be fixed to slinger by vulcanization bonding method like rubber magnets, they are usually simply joined by an adhesive or the like, or formed integrally by insert molding method. However, depending on the type of plastic used as a binder, there is a case where it is impossible to obtain a large adhesive strength equivalent to that in the case of vulcanization adhesion. In such a case, in the severe use environment, there is a possibility that the worst problem of peeling occurs.

  Also, plastic magnets usually do not have the same flexibility as rubber magnets, so there is almost no absorption of thermal expansion differences during sudden temperature changes, just like rubber magnets with an increased amount of magnetic powder. There was a possibility that peeling problems would occur.

The present invention has been made to solve the above-mentioned problems, and its purpose is to prevent the magnet portion from falling off the fixed member even under severe use conditions, and has a high magnetic property and a high-precision rotational speed. An object of the present invention is to provide a highly reliable magnetic encoder manufacturing method and a wheel support rolling bearing unit manufacturing method that enable detection.

The above object of the present invention can be achieved by the following constitution.
(1) A method of manufacturing a magnetic encoder comprising: a fixing member that can be attached to a rotating body; and a substantially annular magnet portion that is attached to the fixing member and is multipolarly magnetized in the circumferential direction.
A step of insert-molding a magnet material composed of a magnetic powder and a thermoplastic resin composition using the fixing member baked in a semi-cured state as a core; and
Curing the adhesive by secondary heating;
A step of magnetizing the magnet portion in a circumferential direction with multiple poles;
A method of manufacturing a magnetic encoder, comprising:
(2) The method for manufacturing a magnetic encoder according to (1), wherein the adhesive contains at least one of a phenol resin and an epoxy resin.
(3) The magnet material contains 60-80% by volume of magnetic powder for anisotropy, and the thermoplastic resin includes polyamide 6, polyamide 12, polyamide 612, polyamide 11, and polyphenylene sulfide. A method of manufacturing a magnetic encoder according to (1) or (2), wherein the method is used.
(4) The method for manufacturing a magnetic encoder according to any one of (1) to (3), wherein unevenness is formed on a surface of the fixing member to which the magnet portion is bonded.
(5) A method for manufacturing a wheel-supporting rolling bearing unit having a magnetic encoder,
The said magnetic encoder is manufactured by the method in any one of (1)-(4), The manufacturing method of the rolling bearing unit for wheel support characterized by the above-mentioned.

The encoder manufacturing method and wheel-supporting rolling bearing unit manufacturing method of the present invention prevent the magnet portion from falling off the fixed member even under severe use conditions, and have high magnetic characteristics and high-accuracy rotation speed detection. It becomes possible and reliable.

  Hereinafter, embodiments of the encoder manufacturing method of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 shows, as an example of an embodiment of the present invention, a case where the present invention is applied to a wheel support rolling bearing unit 2a for supporting a non-driving wheel supported by an independent suspension. Note that the configuration and operation other than the features of the present invention are the same as those of a conventionally well-known structure. Therefore, the description will be simplified, and the features of the present invention will be mainly described below.

  The inner ring 16a that is externally fitted to the small-diameter step portion 15 formed at the inner end portion of the hub 7a is restrained by a caulking portion 23 that is formed by caulking the inner end portion of the hub 7a radially outward. By attaching, it is fixedly coupled to the hub 7a. The hub 7a and the inner ring 16a constitute a rotating wheel. Further, the wheel can be coupled and fixed to a mounting flange 12 formed at a portion protruding from the outer end portion of the outer ring 5a, which is a fixed ring, at the outer end portion of the hub 7a. On the other hand, the outer ring 5a can be coupled and fixed to a knuckle or the like (not shown) constituting a suspension device by a coupling flange 11 formed on the outer peripheral surface thereof.

  Further, seal rings 21a and 21b are provided between the inner peripheral surface of both ends of the outer ring 5a, the outer peripheral surface of the intermediate part of the hub 7a, and the outer peripheral surface of the inner end part of the inner ring 16a, respectively. These seal rings 21a and 21b block the space provided with the balls 17a and 17a from the outer space between the inner peripheral surface of the outer ring 5a and the outer peripheral surfaces of the hub 7a and the inner ring 16a.

  Each of the seal rings 21a and 21b is formed by bending a mild steel plate and reinforcing the elastic members 22a and 22b with core bars 24a and 24b having an L-shaped cross section and an annular shape as a whole. Each of such seal rings 21a and 21b has a metal core 24a and 24b fitted into both ends of the outer ring 5a by an interference fit, and the tip ends of the seal lips formed by the respective elastic members 22a and 22b are connected to the hub. The slinger 25 is externally fitted and fixed to the outer peripheral surface of the intermediate portion 7a or the outer peripheral surface of the inner end portion of the inner ring 16a.

  As shown in FIG. 2, the magnetic encoder 26 includes a slinger 25 that is a fixed member, and a magnetic pole forming ring 27 that is a magnet portion fixed to the side surface of the slinger 25. As shown in FIG. 3, the magnetic pole forming ring 27 is a multipolar magnet, and N and S are alternately formed in the circumferential direction. The magnetic sensor 28 is disposed facing the magnetic pole forming ring 27.

  In the present invention, the magnetic pole forming ring 27 of the magnetic encoder 26 is composed of a multipolar magnet composed of magnetic powder and a plastic composition serving as the binder. In addition, the magnetic encoder according to the present invention uses a slinger baked with a phenol resin adhesive as a core, insert-molds a plastic magnet material, and then completely cures the phenol resin adhesive by secondary heating. Thus, the magnet material and the slinger are integrally bonded and bonded, and then multipolar magnetization is performed in the circumferential direction.

Hereinafter, the phenol resin-based adhesive used for bonding the magnet portion and the slinger of the encoder of the present invention will be described in detail.
The phenolic resin adhesive used in the present invention contains at least a resol type phenolic resin and a bisphenol A type epoxy resin, for example, at 100 ° C. to 120 ° C. under curing conditions of about several minutes to 30 minutes, The slinger can be baked in a semi-cured state that is not washed away by the molten plastic magnet material, and further, the heat from the molten plastic magnet at the time of insert molding and further secondary heating (for example, 130 ° C., about 2 hours) Is completely cured. This phenol resin adhesive has an inorganic filler that has the effect of improving the strain resistance (specific examples include fused silica powder, quartz glass powder, crystal glass powder, glass fiber, alumina powder, talc, and the like. , Aluminum powder, titanium oxide), crosslinked rubber fine particles (specifically, vulcanized acrylonitrile butadiene rubber fine particles having an average particle size of about 30 to 200 nm having a carboxyl group in the molecular chain in order to improve flexibility May be further added.

  In addition, the resol type phenol resin which comprises the phenol resin-type adhesive agent used by this invention is obtained by making phenols and formaldehyde react in presence of a basic catalyst. Examples of the phenols used as the raw material include phenol, m-cresol, p-cresol, a mixture of m-cresol and o-cresol, phenolic hydroxyl groups such as p-tert-butylphenol, p-phenylphenol, and bisphenol A. On the other hand, any one having two or three substitutable nuclear hydrogen atoms at the o- and / or p-position can be used.

  Furthermore, the resol type phenol resin used in the present invention may be a modified resol obtained by introducing o- or p-alkylphenol into a phenol resin, for example. In general, the introduction of o- or p-alkylphenol will improve the flexibility of the phenolic resin. For the same reason, butyl etherified resole obtained by etherifying resole with butyl alcohol, rosin modified resole obtained by reaction of rosin and resole, or the like may be used.

  In addition, in order to improve the adhesive performance and the hardening characteristic as an adhesive agent, a bisphenol A type epoxy resin is added to the phenol resin adhesive according to the present invention. The bisphenol A type epoxy resin may be liquid or solid at room temperature, but it is about 100 parts by weight of phenol resin contained in the adhesive according to the present invention. 1 to 20 parts by weight, or about 5 to 30 parts by weight in the case of a solid resin. The greater the proportion of the bisphenol A type epoxy resin used, the better the adhesive properties. However, when antifreeze resistance or the like is required, the performance tends to decrease.

  Furthermore, a novolac type epoxy resin or a novolac type phenol resin may be added to the phenol resin adhesive according to the present invention for the purpose of imparting toughness. Since these resins react with the resol-type phenol resin in the heating step, the toughness improves as the content increases. However, the content is desirably 30 parts by weight or less per 100 parts by weight of the resol type phenol resin. This is because if novolac type epoxy resin or novolac type phenol resin is used in a proportion higher than this, the adhesion to the plastic magnet may be adversely affected.

  The phenol resin adhesive according to the present invention contains at least a resol type phenol resin and a bisphenol A type epoxy resin in an organic solvent in which ketones such as acetone and methyl ethyl ketone, and alcohols such as methanol and ethanol are generally used. It is prepared and used as an organic solvent solution in which the adhesive composition is dissolved at a solid content concentration of about 5 to 40% by weight.

  As described above, the magnetic encoder using the phenolic resin adhesive according to the present invention was coated on a stainless steel slinger and allowed to air dry for 20 to 60 minutes at room temperature. Thereafter, heat treatment (baking treatment) is performed at about 120 ° C. for about 30 minutes. A slinger, which is heat-treated and baked with an adhesive, is set in a mold, and a plastic magnet material is insert-molded using the slinger as a core. Thereafter, the obtained molded body is heated (secondary curing) at about 130 ° C. for about 2 hours. Furthermore, a magnetic encoder is manufactured by magnetizing the adhesive of the plastic magnet and slinger obtained by heat treatment to multiple poles using a yoke coil.

  Further, as the material of the slinger, ferrite stainless steel (SUS430, etc.), martensitic stainless steel (SUS410, etc.), etc. that do not deteriorate the magnetic characteristics of the encoder magnet and have a corrosion resistance of a certain level or more depending on the usage environment. The magnetic stainless steel is most preferable. However, since the slinger cannot obtain sufficient adhesion simply by degreasing its adhesion surface, in order to ensure highly reliable adhesion, the surface is appropriately roughened by physical or chemical treatment methods. It is preferable to keep the surface. Incidentally, as a particularly preferable surface treatment method of the slinger according to the method for manufacturing the magnetic encoder of the present invention, there is a chemical etching method described in detail in the fourth embodiment. According to this method, the surface irregularities are chemically formed, so there is no shape dependence compared to the irregularities by mechanical methods such as shot blasting, it is uniformly formed on the entire surface, and partially inside the recess. As a result, a sharp (cornered) dent-like unevenness is obtained. That is, the unevenness caused by the chemical etching method has a suitable shape that allows the adhesive to easily enter. Therefore, when a slinger subjected to chemical etching is used, very strong adhesion can be obtained as compared with the case where other treatments are performed or a slinger without unevenness is used. Furthermore, the adhesiveness of the adhesive can be improved by undercoating the slinger with a silane coupling agent as a primer.

  As the plastic magnet material according to the magnetic encoder of the present invention, an anisotropic magnet compound containing 60-80% by volume of magnetic powder for anisotropy and using a thermoplastic as a binder can be suitably used. . As the magnetic powder, ferrite such as strontium ferrite and barium ferrite, rare earth magnetic powder such as neodymium-iron-boron, samarium-cobalt and samarium-iron can be used, and in order to further improve the magnetic properties of the ferrite It may be a mixture of lanthanum and cobalt. When the content of the magnetic powder is less than 60% 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 amount of the resin binder becomes too small, the strength of the entire magnet is lowered, and at the same time, molding becomes difficult and practicality is lowered. As the binder, an injection-moldable thermoplastic resin is suitable, and polyamide resins such as polyamide 6, polyamide 12, polyamide 612, and polyamide 11 and polyphenylene sulfide (PPS) can be used. In addition, since calcium chloride used as a snow melting agent for the encoder may be applied together with water, it is particularly preferable to use polyamide 12, polyamide 612, polyamide 11, or PPS having low water absorption as a resin binder.

  In addition, in order to give the plastic composition which comprises the magnetic encoder based on this invention toughness, for example, in order to improve the adhesiveness with respect to slinger for the fine particle of carboxylated styrene-butadiene rubber vulcanizate, For example, an adhesion modifier such as a copolymer containing glycidyl methacrylate as one component may be added as appropriate.

  The plastic magnet material used in the present invention is preferably a magnetic domain oriented (axial anisotropy) in the thickness direction of the ring-shaped magnet, and the magnetic properties are 1.3 to 15 MGOe in terms of maximum energy product (BHmax). Preferably it is the range of 1.8-12MGOe. When the maximum energy product is less than 1.3 MGOe, the magnetic properties are too low, so it is necessary to dispose the sensor at a considerable distance from the sensor in order to detect the rotational speed. No improvement in performance can be expected. When the maximum energy product exceeds 15 MGOe, it has excessive magnetic properties and cannot be achieved with a composition centered on relatively inexpensive ferrite. A large amount of rare earth magnetic powder such as neodymium-iron-boron is blended. Therefore, it is very expensive, has poor moldability and is not practical. In addition, when rare earths are used as the magnetic powder, the oxidation resistance is lower than that of ferrites. Therefore, in order to maintain stable magnetic properties over a long period of time, a surface treatment layer is further provided on the magnet surface. May be provided. As the surface treatment layer, an electric or electroless nickel plating, an epoxy resin coating film, a silicon resin coating film, a fluororesin coating film, or the like can be specifically used.

  The encoder part is preferably molded by a disk gate type injection molding in which the plastic magnet material melted from the inner diameter thick part simultaneously flows into the mold at a high pressure and is rapidly cooled and solidified in the mold. The molten resin spreads in a disk shape, and then flows into the mold corresponding to the inner diameter thick portion, whereby the flake-like magnetic powder contained therein is oriented in parallel to the surface. In particular, the portion between the inner diameter portion and the outer diameter portion detected by the rotation sensor in the vicinity of the inner diameter thick portion has higher orientation and is very close to the axial anisotropy oriented in the thickness direction. If a magnetic field is applied to the mold in the thickness direction during molding, the anisotropy becomes closer to perfection. Even if magnetic field molding is performed, if the gate is a disk gate 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 in the welded portion where the magnetic properties are deteriorated and the mechanical strength is lowered due to long-term use.

  As described above, according to the manufacturing method according to the present embodiment, it is possible to manufacture a highly reliable magnetic encoder that does not peel off and fall off from the slinger even under severe use conditions. In addition, since the magnetic powder in the plastic magnet obtained by the manufacturing method of the present embodiment is highly oriented in the thickness direction of the annular magnet, the magnetic characteristics of the encoder obtained by the magnetization are extremely good. It will be a thing. For this reason, depending on the content of the magnetic powder in the magnet, it is possible to improve the magnetic flux density, which was conventionally about 20 mT, to 26 mT or more. Therefore, when the gap between the magnetic encoder and the sensor is set to 1 mm as in the prior art, an object that has been multipolarly magnetized to 96 poles is magnetized to more than 120 poles while maintaining the magnetic flux per pole. It is possible. At this time, the single pitch error can be ± 2% or less. That is, according to the magnetic encoder according to the present embodiment, when the air gap is the same as that of the prior art, it is possible to increase the number of poles and improve the detection accuracy of the rotational speed of the wheel. Further, when the plastic magnet according to the present embodiment has the same number of poles as the conventional one, the air gap can be made large, and the degree of freedom in arranging the sensor can be improved.

(Second Embodiment)
Next, a wheel support rolling bearing unit for supporting a non-driven wheel, which is supported by an independent suspension, according to a second embodiment of the present invention will be described in detail. In addition, the same code | symbol is attached | subjected about a part equivalent to 1st Embodiment, and description is abbreviate | omitted or simplified.

  The magnetic encoder 26 of the present embodiment includes a slinger 25 that is a fixing member and a magnetic pole forming ring 27 that is a magnet portion. The magnetic pole forming ring 27 is composed of a magnetic powder having the same composition as that of the first embodiment, a plastic serving as a binder thereof, specifically, a polyamide-based resin and a polyamide plasticizer (hereinafter referred to as “specific polyamide use”). It is comprised by the multipolar magnet which consists of a resin composition to which "the plasticizer" was added.

  As a plastic component in the resin composition, a polyamide-based resin, specifically, calcium chloride used as a snow melting material may be taken together with water in the same manner as in the first embodiment. Polyamide 11, polyamide 12, and polyamide 612 with low properties are used.

  On the other hand, specific plasticizers for polyamide are mainly composed of adducts of phenol or cresol and unsaturated aliphatic esters. Specifically, phenol and methyl oleate or cresol and oleic acid 2 A viscous phenolic resin obtained by reaction with ethylhexyl. By the way, the specific plasticizer for polyamide according to the present embodiment exhibits a plasticizing effect by the interaction of the hydroxyl group of the plasticizer with the amide bond of the polyamide. Is a relatively high molecular weight polymer as a plasticizer, and is difficult to volatilize even under high temperature use. In other words, by using a specific polyamide plasticizer, other polyamide plasticizers such as butylbenzenesulfonamide and 2-ethylhexyl parahydroxybenzoate are often observed when used at high temperatures. Such a change in dimensions and deterioration of physical properties of the molded product are minimized.

  And the compounding quantity of the specific plasticizer for polyamides is 1-20 weight% with respect to the total weight of a resin composition, Preferably it is 5-15 weight%. If the encoder is less than 1% by weight and the absolute amount is too small, sufficient flexibility cannot be imparted so that cracks can be prevented from occurring in a severe temperature environment. On the other hand, if it exceeds 20% by weight, adverse effects such as a decrease in strength and heat resistance of the whole material become apparent, which is not preferable.

Moreover, you may add suitably an antioxidant, a weather resistance improving material, an antistatic material, an inorganic or organic flame retardant, a reinforcing agent, etc. to the resin composition concerning this embodiment as needed.
Note that the slinger 25 and the phenol resin adhesive of the present embodiment are the same as those of the first embodiment.

  The magnetic encoder 26 according to this embodiment is manufactured by inserting a magnet material consisting of a polyamide resin composition containing a specific plasticizer for polyamide and a magnetic powder with a slinger baked with a phenol resin adhesive as a core. After molding, the phenolic resin adhesive is completely cured by secondary heating, and the magnet material and the slinger are integrally bonded and bonded, and then multipolar magnetization is performed in the circumferential direction.

  The plastic magnet material as the molding material is obtained by kneading a polyamide-based resin and a specific polyamide plasticizer with a magnetic powder using a biaxial extruder, kneader or Banbury mixer. Pellets of polyamide resin composition containing body powder are prepared.

  Therefore, according to the magnetic encoder made of a magnetic material comprising the magnetic substance powder and the polyamide-based resin composition containing the specific polyamide plasticizer according to the present embodiment, the magnet portion is obtained by adding the specific polyamide plasticizer. By controlling the crystallinity of the molded product and imparting appropriate flexibility, for example, it becomes possible to suitably absorb the thermal shock applied during a sudden temperature change due to its deformation action. As a result, surface cracks are prevented from occurring. Therefore, in addition to the effects of the first embodiment, it is possible to manufacture a more reliable magnetic encoder that does not peel off and fall off from the slinger even under use conditions such as repeated vibration and cooling.

(Third embodiment)
Next, the rolling bearing unit assembled with the magnetic encoder-equipped sealing device according to the third embodiment of the present invention will be described in detail.

  As shown in FIGS. 4 and 5, a rolling bearing unit 30 including a magnetic encoder according to the present embodiment includes an outer ring 31 that is a fixed ring, an inner ring 32 that is a rotating ring (rotating body), an outer ring 31 and an inner ring. A ball 33, which is a plurality of rolling elements that are rotatably arranged in an annular gap defined by 32 and held at equal intervals in the circumferential direction by a cage 34, and an opening end of the annular gap. The sealing device 35, the magnetic encoder 36, and the sensor 37 are provided.

  The sealing device 35 includes a seal member 40 mounted on the inner peripheral surface of the outer ring 31, and a slinger 50 disposed on the outer side of the bearing than the seal member 40 and fixed to the outer peripheral surface of the inner ring 32. The sealing member 40 and the slinger 50 close the opening end of the annular gap to prevent foreign matters such as dust from entering the inside of the bearing and prevent the lubricant filled in the bearing from leaking. . The magnetic encoder 36 includes a slinger 50 and a magnet portion 60 attached to the slinger 50. The magnet portion 60 is fixed to the inner ring 32 that is a rotating body with the slinger 50 as a fixing member.

  The seal member 40 is configured by reinforcing a seal lip 42 similarly formed in an annular shape having a substantially L-shaped cross section with a core metal 41 formed in an annular shape having a substantially L-shaped cross section. It is installed. The front end portion of the seal lip 42 is branched into a plurality of sliding contact portions, and each sliding contact portion is formed on the end surface facing the bearing inward of the flange portion 52 of the slinger 50 or the outer peripheral surface of the fitting portion 51. They are in sliding contact with each other around the circumference. Thereby, a high sealing force is obtained.

  The slinger 50 is formed in an annular shape having an L-shaped cross section, and has a substantially cylindrical fitting portion 51 that is fitted on the outer peripheral surface of the inner ring 32, and a hook-like shape that is radially expanded from one end of the fitting portion 51. The flange portion 52 and a protruding portion 53 that protrudes outward in the axial direction from the flange portion 52 on the inner diameter side of the flange portion 52 by bending one end portion of the fitting portion 51. Further, a cutout 54 that is partially formed in the circumferential direction is provided on the outer peripheral surface of the protruding portion 53. A magnet portion 60 that changes a nearby magnetic field (for example, magnetic flux density) in synchronism with the rotation of the inner ring 12 is joined to an end surface (hereinafter referred to as a joining surface) 52 a facing the bearing outward of the flange portion 52. ing. At the same time, the magnet portion 60 is also mechanically joined to the outer peripheral portions of the notch 54 and the flange portion 52.

  As in the first embodiment, the slinger 40 is made of magnetic stainless steel such as ferritic stainless steel (SUS430, etc.), martensitic stainless steel (SUS410, etc.). Then, the surface of the magnetic stainless steel slinger of this embodiment is subjected to a roughening treatment by chemical etching treatment in the following steps.

  In the first step, after the surface of the slinger is cleaned with an alkaline degreasing agent, it is dipped in dilute hydrochloric acid at room temperature for several minutes and pickled, and then an iron oxalate treatment solution containing at least oxalate ions and fluorine compound ions For several minutes to form an iron oxalate film on the surface. In the second step, the magnetic stainless steel slinger with this iron oxalate film formed is immersed in an aqueous solution of nitric acid-hydrofluoric acid mixed acid at room temperature for several minutes until the underlying stainless steel is not immersed. Most of the iron oxalate film is removed, and chemical etching unevenness is formed on the surface of the slinger. Since these irregularities are formed chemically, there is no shape dependency compared to mechanical irregularities by shot blasting etc., and it is uniformly formed on the entire surface, and the inner space of the concave part is partially widened It becomes a sharp (cornered) concave-convex shape. Thereby, by performing insert molding using the slinger as a core, the melted plastic magnet material enters the recess and is mechanically joined. In addition, it is easy for the adhesive to enter the unevenness, and the adhesive is applied to the slinger and insert-molded using the core that has been baked in the latter-half-cured state. It is possible to achieve a strong adhesion state compared to the conventional one.

  Furthermore, you may perform the 3rd process of improving rust prevention property or the adhesiveness of an adhesive agent. A specific example of the treatment to improve rust prevention is the iron oxalate film treatment used in the second step, but it is formed with fine crystals that do not cover the uneven surface formed in the second step. A thin film is preferred. As a means for obtaining this fine crystal, a method of forming a crystal nucleus by immersing in a surface conditioning solution before the treatment is effective.

  A silane coupling agent treatment is effective as a treatment for improving the adhesiveness of the adhesive. The silane coupling agent film acts as a primer for the adhesive, and preferably has an amino group, an epoxy group, etc. that are highly reactive with the functional group of the adhesive at one end, specifically, γ-aminopropyltriethoxysilane. Γ-glycidoxypropyltriethoxysilane and the like, which are formed by dipping in a dilute solution such as alcohol and drying as necessary. The thickness of the film formed in the third step is 0.01 to 1.0 μm, more preferably 0.01 to 0.5 μm. When the thickness of the film is less than 0.01 μm, the effect of improving rust prevention and adhesiveness becomes poor, which is not preferable. On the other hand, if the thickness of the film exceeds 1.0 μm, the ratio of covering the uneven surface provided in the second step increases, which is not preferable. The unevenness state of the surface of the slinger obtained through the second step or the third step is 0.2 to 2.0 μm at the arithmetic average height Ra defined by JIS B 0601 (2001), and the maximum height. Rz is about 1.5 to 10 μm. If the unevenness is less than the lower limit, it becomes difficult to exhibit the wedge effect. On the other hand, if the unevenness exceeds the upper limit value, the wedge effect is improved accordingly, but it is difficult to achieve by the chemical etching method, and the sealing performance with the rubber seal lip with which the back surface of the slinger contacts is preferably reduced. Absent.

  As described above, the encoder according to the present invention is capable of mechanically joining the melted plastic magnet material into the unevenness provided by chemical etching by insert molding, but in order to improve reliability, It is more preferable to interpose an adhesive layer between them. The adhesive layer is in a semi-cured state so that it is not desorbed and washed away by the high-pressure plastic magnet material melted during insert molding, and is completely cured by heat from the molten resin or in addition to secondary heating after molding. It becomes a state. Adhesives that can be used can be diluted with a solvent, and phenol resin adhesives and epoxy resin adhesives that progress in a two-step curing reaction are considered in consideration of heat resistance, chemical resistance, and handling properties. It is preferable.

  The phenol resin-based adhesive is preferably used as a rubber vulcanized adhesive, and the composition is not particularly limited, but a novolac-type phenol resin, a resol-type phenol resin, and a curing agent such as hexamethylenetetramine. Can be used in which methanol or methyl ethyl ketone is dissolved. Further, the phenol resin adhesive may be the one used in the first embodiment.

  As the epoxy resin adhesive, a one-pack type epoxy adhesive that can be diluted into a solvent is suitable as a stock solution. This one-pack type epoxy adhesive, after evaporating the solvent, becomes a semi-cured state on the slinger surface at an appropriate temperature and time so as not to be washed away by the high-temperature and high-pressure molten resin at the time of insert molding. The resin is completely cured by heat from the resin and secondary heating.

  The one-pack type epoxy adhesive used in the present invention comprises at least an epoxy resin and a curing agent, and the curing agent hardly undergoes a curing reaction near room temperature. For example, a thermosetting reaction is not performed until heat of 100 ° C. or higher is applied. Is advancing. This adhesive was stressed by other epoxy compounds used as reactive diluents, curing accelerators that improve the thermal cure rate, inorganic fillers that have the effect of improving heat resistance and strain resistance, and stress Cross-linked rubber fine particles or the like that improve flexibility that sometimes deforms may be further added.

  As the epoxy resin, those having two or more epoxy groups in the molecule are preferable in that a crosslinked structure capable of exhibiting sufficient heat resistance can be formed. Also, 4 or less, and further 3 or less are preferable from the viewpoint that a low-viscosity resin composition can be obtained. If the number of epoxy groups contained in the molecule is too small, the heat resistance of the cured product tends to decrease and the strength tends to decrease. On the other hand, if the number of epoxy groups contained in the molecule is too large, the resin This is because the viscosity of the composition increases and the curing shrinkage tends to increase.

  The number average molecular weight of the epoxy resin is preferably 200 to 5500, particularly preferably 200 to 1000 from the viewpoint of balance of physical properties. If the number average molecular weight is too small, the strength of the cured product tends to decrease and the moisture resistance tends to decrease.On the other hand, if the number average molecular weight is too large, the viscosity of the resin composition increases and workability adjustment is possible. This is because there is a tendency that the use of a reactive diluent increases.

  Furthermore, the epoxy equivalent of the epoxy resin is preferably 100 to 2800, particularly 100 to 500 from the viewpoint that the blending amount of the curing agent is within an appropriate range. If the epoxy equivalent is too small, the amount of the curing agent will increase too much and the physical properties of the cured product will deteriorate. On the other hand, if the epoxy equivalent is too large, the amount of the curing agent will decrease and the epoxy resin will decrease. This is because the molecular weight of the resin itself tends to increase and the viscosity of the resin composition increases.

  Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, naphthalene type epoxy resin, biphenyl type epoxy resin, glycidylamine type epoxy resin, alicyclic epoxy resin, dicyclopentadiene. Type epoxy resin, phenol novolac type epoxy resin, polyester modified epoxy resin, copolymer with other polymers such as silicon modified epoxy resin, and the like. Among these, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, naphthalene type epoxy resin, phenol novolac type epoxy resin, etc. have a relatively low viscosity and excellent heat resistance and moisture resistance of the cured product. Therefore, it is preferable.

  As the curing agent, an amine curing agent, a polyamide curing agent, an acid anhydride curing agent, a latent curing agent, or the like can be used.

  The amine-based curing agent is an amine compound and does not generate an ester bond by a curing reaction. Therefore, the amine-based curing agent is preferable because it has excellent moisture resistance as compared with the case where an acid anhydride-based curing agent is used. As the amine compound, any of an aliphatic amine, an alicyclic amine, and an aromatic amine may be used, but the aromatic amine is most preferable because the storage stability of the blend at room temperature is high and the cured product has high heat resistance. .

  As aromatic amines, 3,3′-diethyl-4,4′-diaminodiphenylmethane, 3,5-diethyl-2,6-toluenediamine, 3,5-diethyl-2,4-toluenediamine, 3,5 Examples thereof include a mixture of diethyl-2,6-toluenediamine and 3,5-diethyl-2,4-toluenediamine, and the like.

  The polyamide-based curing agent is also called a polyamidoamine, and is a compound having a plurality of active amino groups in the molecule and similarly having one or more amide groups. A polyamide-based curing agent synthesized from polyethylene polyamine is preferable because it produces an imidazirine ring by secondary heating and improves compatibility with the epoxy resin and mechanical properties. The polyamide curing agent may be an adduct type in which a small amount of epoxy resin has been reacted in advance, and by using the adduct type, the compatibility with the epoxy resin is excellent, and the curing drying property and water / chemical resistance are improved. preferable. By using this polyamide-based curing agent, a tough cured resin having a particularly high flexibility is obtained by crosslinking with the epoxy resin, and therefore, it is excellent in the thermal shock resistance required for the magnetic encoder of the present invention, and is suitable.

  Cured products cured with acid anhydride curing agents have high heat resistance and excellent mechanical and electrical properties at high temperatures, but tend to be somewhat brittle, but are curing accelerators such as tertiary amines. Can be improved by combining with. Examples of acid anhydride-based curing agents include phthalic anhydride, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methyleneendomethylenetetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, trimellitic anhydride, etc. Can do.

  The latent curing agent has excellent storage stability at room temperature in a mixed system with an epoxy resin, and cures rapidly under conditions of a certain temperature or more. As an actual form, a curing agent for an epoxy resin Neutral salts or complexes of acidic or basic compounds that can be activated when heated, those that harden in microcapsules and break down by pressure, crystalline, high melting point, compatible with epoxy resins at room temperature There are some materials that are not dissolved by heating.

  As the latent curing agent, 1,3-bis (hydrazinocarboethyl) -5-isopropylhydantoin, eicosanedioic acid dihydrazide, adipic acid dihydrazide, dicyandiamide, 7,11-octadecadien-1 which is a high melting point compound , 18-dicarbohydrazide and the like. Among these, 7,11-octadecadien-1,18-dicarbohydrazide is used as a curing agent, and thus becomes a tough cured resin rich in flexibility by crosslinking with an epoxy resin. It is excellent in thermal shock resistance required for the magnetic encoder of the invention and is suitable.

  As the reactive diluent, t-butylphenyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, or the like can be used. Flexibility can be imparted. However, these reactive diluents, when used in a large amount, reduce the moisture resistance and heat resistance of the cured product, and therefore, preferably 30% or less, more preferably 20%, based on the weight of the main epoxy resin. It is added in the following ratio.

The curing accelerator is preferably one that has sufficient storage stability without accelerating the curing reaction at room temperature and rapidly proceeds with the curing reaction when the temperature reaches 100 ° C. or higher. And compounds having one or more ester bonds produced by the reaction of 1-alkoxyethanol and carboxylic acid. This compound is for example represented by the general formula (I):
^{R 3 [COO-CH (OR} 2) -CH 3] n (I)
(In the formula, R ³ is an n-valent hydrocarbon group having 2 to 10 carbon atoms and optionally containing one or more of nitrogen atom, oxygen atom, etc., R ² is 1 to 6 carbon atoms, A monovalent hydrocarbon group which may contain one or more of a nitrogen atom, an oxygen atom and the like, and n is an integer of 1 to 6. A specific example is shown in Chemical Formula 1.

As another example, the compound of R ² is a propyl group in R ³ is a divalent phenyl radical, in R ³ is a trivalent phenyl group the compound of R ² is a propyl group, with R ³ is a tetravalent phenyl group Examples thereof include compounds in which R ² is a propyl group. These may be used alone or in combination of two or more. Among these, the compound represented by Chemical Formula 1 is most preferable from the viewpoint of the balance between curing reactivity and storage stability.

  In addition to the compounds described above, imidazole compounds such as 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, and 2-phenylimidazole may be used as the curing accelerator.

  Further, as a curing accelerator, a carboxylic acid such as adipic acid, which is a compound having active hydrogen that reacts with an epoxy group to cause a ring-opening reaction, may be used. By using adipic acid as a curing accelerator, it reacts with the epoxy group of the epoxy resin and the amino group of the curing agent, and the resulting cured product becomes flexible as the amount of adipic acid added increases. In order to express flexibility, the amount of adipic acid added is 10 to 40% by weight, more preferably 20 to 30% by weight, based on the total amount of the adhesive. When the addition amount is less than 10% by weight, sufficient flexibility is not exhibited. On the other hand, when the addition amount exceeds 40% by weight, the total amount of the epoxy resin in the adhesive is reduced correspondingly, and the adhesive force and mechanical strength are lowered. Since adipic acid is also a starting material for polyamide resin, if the binder of magnetic powder is a polyamide-based resin such as polyamide 12 or polyamide 6, it reacts with a monomer or oligomer component remaining in a trace amount in the binder material itself. The adhesive composition contains adipic acid, and stronger adhesion is possible.

  Further, as a curing accelerator, a tertiary amine such as dimethylbenzylamine, a quaternary ammonium salt such as tetrabutylammonium bromide, which acts as a catalyst for promoting a ring-opening reaction of an epoxy group, 3- (3 ′, 4′-dichlorophenyl) An alkyl urea such as -1,1-dimethylurea may be added.

  The OH groups generated by the ring-opening reaction, including the amines described above, form hydrogen bonds with the hydroxyl groups on the metal surface, which is the adherend, and also act on the amide bonds of nylon, which is the binder material. And can maintain a strong adhesive state.

  The inorganic filler can be used without particular limitation as long as it is conventionally used. Examples thereof include fused silica powder, quartz glass powder, crystalline glass powder, glass fiber, alumina powder, talc, aluminum powder, and titanium oxide.

  As the crosslinked rubber fine particles, those having a functional group capable of reacting with an epoxy group are preferred, and specifically, vulcanized acrylonitrile butadiene rubber having a carboxyl group in the molecular chain is most preferred. A finer particle diameter is preferable, and an ultrafine particle having an average particle diameter of about 30 to 200 nm is most preferable in order to exhibit dispersibility and stable flexibility.

  The one-component epoxy adhesive described above hardly undergoes a curing reaction at room temperature, for example, becomes semi-cured at about 80 to 120 ° C., and is completely cured by applying high-temperature heat at 120 to 180 ° C. The reaction proceeds. More preferably, the curing reaction proceeds at a temperature of 150 to 180 ° C. in a relatively short time, and the one that can be bonded by high-frequency heating at about 180 ° C. is most preferable.

The cured product after the thermosetting of the phenol resin-based adhesive and the epoxy resin-based adhesive described above has a physical property of flexural modulus or Young's modulus of 0.02 to 5 GPa, more preferably 0.03 to 4 GPa. Yes, or hardness (durometer D scale; HDD) is preferably in the range of 40 to 90, more preferably 60 to 85. When the flexural modulus or Young's modulus is less than 0.02 GPa or the hardness (HDD) is less than 40, the adhesive itself is too soft and easily deforms due to vibrations during running of an automobile or the like, and thereby the magnet part moves easily. For this reason, the detection accuracy of the rotational speed may be lowered, which is not preferable. On the other hand, if the flexural modulus or Young's modulus exceeds 5 GPa or the hardness (HDD) exceeds 90, the adhesive itself is too hard and the thermal expansion / contraction difference between the magnet of the magnetic encoder and the fixing member (that is, both It is difficult to deform so as to absorb the difference in expansion and contraction due to the difference in linear expansion coefficient. The one-pack type epoxy adhesive of the present invention is required to have thermal shock resistance when used in an automobile, and more preferably has flexibility (deforms when stressed) in a cured state.
The material of the magnet part of the magnetic encoder is the same as that of the first embodiment.

  As for the molding method of the magnetic encoder, the disk gate type injection molding is preferable as in the first embodiment. Therefore, in the present embodiment, first, the slinger performs chemical etching treatment on the magnetic stainless steel to roughen the surface as shown in the cross-sectional electron micrograph of FIG. A cured film is formed. Then, in a state where a magnetic field is applied in the thickness direction using the slinger as a core, the magnet raw material is injection-molded (insert molding) using a disk gate on the inner peripheral portion, whereby the molten magnet raw material is formed into a ring shape. Thereafter, it is demagnetized by applying a reverse magnetic field during cooling and solidification in the mold, and then taken out. Furthermore, after performing the gate cut, in order to completely heat cure the adhesive, it is heated at a constant temperature for a certain time in a thermostatic bath or the like. Depending on the case, it is good also as a process which hardens | cures completely by high temperature and short time heating, such as high frequency heating, in a process. In insert molding, the melted magnet material enters the notch 54 of the protruding portion 53 of the slinger 50 and is mechanically joined, and also wraps around the outer peripheral portion of the flange portion 52 and mechanically joined. ing.

  After bonding, the magnets are magnetized together with the magnetizing yoke in the circumferential direction by a magnetizer. 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.

In the magnetic encoder of this embodiment, the slinger is subjected to a roughening (unevenness) process accompanied by a chemical etching process in which the internal space is partially expanded. In addition to improving the adhesiveness of the parts, the use of phenolic adhesives or epoxy adhesives as the adhesive allows high temperature, low temperature, and thermal shock during transition between high and low temperatures to which the undercarriage part of the automobile is exposed. The adhesive portion is less likely to be peeled off by various chemicals such as grease and oil, and the reliability is improved. In addition, using a special adhesive that can be cured in two stages, and performing insert molding with a semi-cured adhesive baked, mechanically and chemically, the slinger and the magnet can be joined. As a result, productivity and reliability are further improved.
(Fourth embodiment)
Next, a detailed description will be given of a rolling bearing unit assembled with a magnetic encoder-equipped sealing device according to a fourth embodiment of the present invention. In addition, about the equivalent part to the rolling bearing unit of 3rd Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted or simplified.
In the bearing unit of the present embodiment, the slinger 70 does not have the protruding portion as in the third embodiment, and the flange portion 72 is formed by bending the end portion of the fitting portion 71 vertically. Therefore, the magnet part 60 is joined to the slinger 70 at the surface of the flange part 72 roughened by the chemical etching process and the outer peripheral part of the flange part 72, and the magnet part 70 is prevented from being peeled off from the slinger 72. be able to.
Other configurations and operations are the same as those of the third embodiment.

(Fifth embodiment)
Next, a wheel support rolling bearing unit for supporting a non-driven wheel, which is supported by an independent suspension, according to a fifth embodiment of the present invention will be described in detail. In addition, since this embodiment is the same as that of 1st Embodiment in the shape of the rolling bearing unit containing a magnetic encoder, it demonstrates with reference to FIGS. 1-3. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  In the magnetic encoder 26 of this embodiment, when the plastic magnet material is insert-molded with the slinger as the core, the set slinger 25 has a phenol resin / epoxy resin-based adhesive as an undercoat adhesive and a phenol as an overcoat adhesive. It differs from the magnetic encoder of the first embodiment in that the resin adhesive is baked.

  As with the first embodiment, the material of the slinger 25 is most preferably a magnetic material such as ferritic stainless steel (SUS430 or the like) or martensitic stainless steel (SUS410 or the like) having a certain level or more of corrosion resistance. Further, in order to ensure highly reliable adhesion, it is preferable that the bonding surface of the slinger is made to have an appropriate surface roughness by a technique such as a shot blast method or the above-described chemical etching method.

  An undercoat adhesive containing a phenol resin and an epoxy resin is applied to the joining surface of the stainless slinger 25.

  In general, epoxy resin adhesives are used for water-resistant applications, but in order to improve the adhesion between the epoxy resin adhesive and the stainless steel that is the slinger material, undercoat bonding is used to bond plastic magnets and slinger. As an agent, an organic solvent solution of an adhesive composition composed of an epoxy resin and a phenol resin is used. That is, this undercoat adhesive ensures a large adhesive force to the slinger due to the presence of the phenolic hydroxyl group of the phenol resin, while imparting water resistance of the adhesive by the epoxy resin.

  The phenol resin contained in the undercoat adhesive is specifically a resol type phenol resin, and is obtained by reacting phenols with formaldehyde in the presence of a basic catalyst. Examples of the phenols used as the raw material include phenol, m-cresol, p-cresol, a mixture of m-cresol and o-cresol, phenolic hydroxyl groups such as p-tert-butylphenol, p-phenylphenol, and bisphenol A. On the other hand, any one having 2 or 3 substitutable nuclear hydrogen atoms at the o- and / or p-position can be used.

  Further, the resol type phenol resin may be a modified resol obtained by introducing o- or p-alkylphenol into a phenol resin, for example. Usually, the introduction of o- or p-alkylphenol will improve the flexibility of the phenolic resin, leading to improved reliability of the adhesive layer (for example, against mechanical stress such as thermal stress). For the same reason, butyl etherified resole obtained by etherifying resole with butyl alcohol, rosin modified resole obtained by reaction of rosin and resole, or the like may be used.

On the other hand, the epoxy resin contained in the undercoat adhesive is of the glycidyl type, and is an epoxy resin obtained from epichlorohydrin and an active hydrogen compound. In addition, as active hydrogen compounds, there are phenol derivatives, glycols, organic acids, amines, etc., and any of them may be used. However, in view of the maintenance stability and cost as an adhesive, Use is preferred. As the phenol derivative, dihydric phenols such as bisphenol A and bisphenol F, or polyhydric phenols such as phenol novolac and orthocresol novolac can be used.

By the way, since the undercoat adhesive is particularly required to have a function as a water-resistant primer, the glycidyl type epoxy resin contained in the undercoat adhesive is glycidyl for the purpose of further improving the water resistance and salt water resistance. The main skeleton of the epoxy resin may be modified. That is, an epoxy resin into which fluorine (mainly CF ₃ group) is introduced as a hydrophobic skeleton, specifically, a bisphenol AF type epoxy resin may be used. In addition, a naphthalene type epoxy resin derived from mononaphthols or a dicyclopentadiene type epoxy resin can be suitably used because of its excellent moisture resistance. Further, a rubber-modified epoxy resin in which a liquid acrylonitrile butadiene (NBR) rubber is reacted with an epoxy group and a rubber component is dissolved in an epoxy resin, or a crosslinked NBR, a crosslinked acrylic rubber, a silicone rubber or the like is dispersed in an epoxy resin. Since the rubber-modified epoxy resin has good water resistance due to the hydrophobic effect of the rubber component, these can also be suitably used as the epoxy resin contained in the undercoat adhesive.

  In addition, in the epoxy resin contained in the undercoat adhesive, in order to improve the adhesion to the slinger (made of stainless steel), a ligand that forms a chelate bond with a metal is incorporated in the epoxy resin, and the chelate deformed epoxy resin You may use what we did. Since the ligand in the chelate-modified epoxy resin forms a coordination bond on the surface of the slinger, the intermolecular attractive force between the epoxy resin and the slinger can be improved.

  Each component of the undercoat adhesive is used in a proportion of about 40 to 400 parts by weight, preferably about 50 to 150 parts by weight, of a resol type phenol resin with respect to 100 parts by weight of the epoxy resin described above. When the proportion of the resol type phenol resin is larger than this, the water-resistant adhesiveness is deteriorated. On the other hand, when the proportion is less than this, the adhesion to the slinger is lowered, which is not preferable.

  The undercoat adhesive containing the phenol resin and the epoxy resin described above has a component concentration of about 0.5 to 20% by weight in a single solvent or a mixed solvent of isopropyl alcohol, methyl ethyl ketone, or methyl isobutyl ketone. Used as a dissolved organic solvent solution.

  The above-mentioned undercoat adhesive is applied on the slinger 25 by a method such as dip coating, spray coating, brush coating, and the like, and after being dried at room temperature for about 20 to 60 minutes, It is baked on the slinger 25 at 120 to 200 ° C. under a drying and curing condition of about 5 to 30 minutes.

  The topcoat adhesive is prepared as an organic solvent solution in which an adhesive composition mainly composed of a resol type phenol resin is dissolved at a solid content concentration of about 5 to 40% by weight. As an adhesive mainly composed of such a resol type phenol resin, for example, TS1677-13 manufactured by Road Far East Co., Ltd. or a certain amount of epoxy resin is used. N-15 or Metalock N-23 can be used. The same coating method as that for the undercoat adhesive is also applied to the topcoat adhesive. In addition, as drying / curing conditions, for example, the drying process is performed at a temperature of 100 to 150 ° C. for several minutes to 30 minutes, and the slinger is in a semi-cured state that does not flow out by a high-temperature and high-pressure molten plastic magnet at the time of insert molding. It is baked. And it hardens | cures completely by the heat from the molten plastic magnet at the time of insert molding, and also secondary heating (for example, 150 degreeC, about 2 hours) following it.

  As a plastic magnet material according to the magnetic encoder of the present embodiment, an anisotropic magnet containing 60-80% by volume of anisotropic magnetic powder and using a polyamide resin composition as a binder, as in the first embodiment. A compound can be suitably used. As the magnetic powder, ferrite such as strontium ferrite and barium ferrite, rare earth magnetic powder such as neodymium-iron-boron, samarium-cobalt and samarium-iron can be used, and in order to further improve the magnetic properties of the ferrite It may be a mixture of lanthanum and cobalt.

  Further, as the binder, it is sufficiently assumed that the magnetic encoder is used under a severe environment, that is, an environment where repeated thermal shock is applied. Under such circumstances, for example, −40 In order to make the reliability more reliable under conditions where repeated thermal shock is applied at a temperature of from 120 ° C. to 120 ° C., a polyamide resin and a soft resin whose molecular structure has a glass transition temperature of at least −40 ° C. or lower It is a polymer alloy with a polyamide-based block copolymer containing segments. That is, the resin composition as a binder is a polymer alloy of a polyamide resin and a polyamide-based block copolymer containing a soft segment, and the flexibility at low temperature (low temperature toughness) is improved. The resistance to repeated thermal shock at ℃ is improved.

  As the hard segment in the polyamide block copolymer according to the present embodiment, that is, the polyamide block component, aliphatic polyamides such as polyamide 12, polyamide 11, and polyamide 6 can be used. However, considering market availability, the choice of polyamide 12 is practical.

  Moreover, as a soft segment of a polyamide-type block copolymer, a glass transition temperature should just be -40 degrees C or less, and it does not specifically limit by other properties. As candidates for the soft segment, polyester, polyether, polybutadiene, polyisoprene, polycarbonate, polycaprolactam, and the like are considered, and there are many choices. However, considering the ease of availability from the market, it is currently optimal to select a block copolymer having polyester or polyether in the soft segment. In particular, in consideration of hydrolysis resistance, the latter block copolymer containing a polyether segment can be considered more suitable. Specific examples of the polyether segment include polytetramethylene oxide, polypropylene oxide, polyethylene oxide, and copolymers thereof. In addition, the compounding quantity of the polyamide-type block copolymer demonstrated above is 5-55 weight% with respect to the total weight of a resin composition, Preferably it is 10-45 weight%. If it is less than 5% by weight, the absolute amount is too small to provide the desired low-temperature flexibility. On the other hand, if it exceeds 55% by weight, the heat resistance is particularly insufficient, and it is not suitable for use as a magnet material for a magnetic encoder.

  In addition, since the resin composition according to the present embodiment contains a block copolymer containing a soft segment in which the molecular chain is in active thermal motion, the addition of a stabilizer is essential for its stabilization. is there. That is, an antioxidant (phenols, copper halide) for quickly removing deterioration factors is added to the resin composition. Furthermore, a heat stabilizer, a light stabilizer, an antistatic material, an inorganic or organic flame retardant, and other reinforcing materials may be added as necessary.

  Note that the binder used in this embodiment may be the thermoplastic used in the first embodiment.

As in the first embodiment, the plastic magnet material is preferably one having a magnetic domain orientation (axial anisotropy) in the thickness direction of the ring-shaped magnet, and the magnetic properties are 1.3 to 15 MGOe at the maximum energy product (BHmax), More preferably, it is the range of 1.8-12MGOe. In addition, when rare earth is used as the magnetic powder, a surface treatment layer such as electric or electroless nickel plating, epoxy resin coating, silicon resin coating, or fluororesin coating may be further provided on the magnet surface. Good.
Further, it is preferable that the molding of the encoder unit of the present embodiment is performed by disk gate type injection molding, as in the first embodiment.

Therefore, according to the manufacturing method of the magnetic encoder of the present embodiment, a phenol resin / epoxy resin-based adhesive as an undercoat adhesive and a stainless slinger baked with a phenol resin adhesive as an overcoat adhesive are used as cores. After magnet molding containing magnetic powder and polyamide resin composition is insert-molded, the adhesive is cured by secondary heating, the magnet material and slinger are integrally bonded and joined, and then multipolar magnetization in the circumferential direction Therefore, even under a severe environment such as salt spray, it is possible to produce a magnetic encoder made of a plastic magnet having excellent adhesion without causing separation at the interface between the SUS steel plate and the adhesive. .
Other operations and effects are the same as those in the first embodiment.

In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably.
The magnetic encoder according to each embodiment can be applied to any bearing unit. The magnetic encoder according to the first, second, and fifth embodiments is applied to the rolling bearing unit according to the third and fourth embodiments, and the third and fourth embodiments. The magnetic encoder may be applied to the rolling bearing units of the first, second, and fifth embodiments.

  Hereinafter, the present invention will be further described with reference to examples and comparative examples, but the present invention is not limited thereto.

First, the adhesive force difference based on the difference between the bonding method and the adhesive was evaluated by the following method.
Example 1

A phenol resin adhesive (Metaloc N-15, manufactured by Toyo Chemical Laboratory) is coated on a SUS430 plate (width 40 mm, length 100 mm, thickness 1 mm) roughened with sandpaper, and air-dried at room temperature for about 30 minutes. Then, heat treatment was performed at 120 ° C. for 30 minutes. A SUS430 plate material baked with this adhesive is set in a mold, and this is used as a core for a plastic magnet material (Strontium ferrite-containing 12 nylon-based anisotropic plastic magnet compound FEROTOP TP-A27N (Totium ferrite content 75 manufactured by Toda Kogyo). Insert molding of volume%)) was performed. However, the size of the plastic magnet to be molded is 20 mm in width, 30 mm in length, and 3 mm in thickness. The portion to be injection-molded on the SUS430 plate, that is, the bonding area between the plastic magnet and the SUS430 plate is 200 mm ² (20 mm × 10 mm). It is. Thereafter, this joined body was heated (secondary curing) at 130 ° C. for 2 hours to obtain a test body of Example 1.

(Example 2)
The test body of Example 2 was obtained by the same method as (Example 1) except that the phenol resin-based adhesive used was Metaloc N-23 manufactured by Toyo Chemical Laboratory.

(Comparative Example 1)
A phenol resin adhesive (Metaloc N-15 manufactured by Toyo Chemical Laboratory) is applied onto a SUS430 plate (40 mm wide, 100 mm long, 1 mm thick) whose surface has been roughened with sandpaper, and air-dried at room temperature for about 30 minutes. After that, heat treatment was performed at 120 ° C. for 30 minutes. On a SUS430 plate material baked with this adhesive, a test piece (width 20 mm) of a plastic magnet (12 strontium ferrite-containing 12 nylon-based anisotropic plastic magnet compound FERTOP TP-A27N (stoichiometric ferrite content 75 volume%) manufactured by Toda Kogyo) , 30 mm in length and 3 mm in thickness) with a fixing jig or the like so that the bonding area becomes 200 mm ^2, and then subjected to heat treatment at 130 ° C. for 2 hours to obtain a specimen of Comparative Example 1 It was.

(Comparative Example 2)
A test body of Comparative Example 2 was obtained in the same manner as (Comparative Example 1) except that the phenol resin adhesive used was Metaloc N-23 manufactured by Toyo Chemical Laboratory.

(Comparative Example 3)
A one-pack type epoxy resin adhesive (LOCTITE Hysol 9432NA manufactured by Henkel Japan) is applied onto a SUS430 plate material (width 40 mm, length 100 mm, thickness 1 mm) whose surface is roughened with sandpaper, and a plastic is applied to the SUS430 plate material. Bonding area of magnet (strontium ferrite-containing 12 nylon-based anisotropic plastic magnet compound EROTOP TP-A27N (storium ferrite content 75% by volume)) test piece (width 20 mm, length 30 mm, thickness 3 mm) manufactured by Toda Kogyo Was fixed with a fixing jig or the like so as to be 200 mm ^2, and then subjected to a heat treatment at 120 ° C. for 1 hour to completely cure the adhesive, and a test body of Comparative Example 3 was obtained.

(Comparative Example 4)
The adhesive used is a two-pack type epoxy resin adhesive (LOCTITE E-20HP manufactured by Henkel Japan), and the heat treatment is unnecessary, and the method of Comparative Example 4 is performed in the same manner as in (Comparative Example 3). A specimen was obtained.

  The above six types of adhesion test pieces were each subjected to a tensile test at a tensile speed of 5 mm / min, and the shear adhesive strength (average value) of each adhesive was evaluated. The experimental results are shown in Table 1 below.

  From Table 1, Example 1 and Example 2 in which the joining surface of the plastic magnet test piece and the SUS material plate is molded and bonded are intended to ensure the adhesive force only by the secondary curing of the phenol resin adhesive. Compared with Comparative Example 1 and Comparative Example 2 or Comparative Example 3 and Comparative Example 4 simply bonded using one-component epoxy and two-component epoxy adhesives, higher adhesive strength is ensured. I understood it.

  Next, a magnetic encoder was produced using a magnetic powder and a plastic magnet material made of a resin composition in which a specific polyamide plasticizer was added to a polyamide-based resin.

(Examples 3 to 6)
As a plastic material of each Example 3-6, what consists of a mixing | blending composition of a magnetic body powder and a resin composition as shown in Table 2 was used.

  In production, first, a specific polyamide plasticizer is kneaded into a polyamide-based resin by a twin-screw extruder, a kneader, a Banbury mixer, or the like. The kneading is performed at a temperature of 160 to 280 ° C. for 1 to 20 minutes. Thereafter, the polyamide resin composition is pelletized by a usual method. Furthermore, the polyamide-based resin composition pellets are put into the magnetic powder, kneaded for 1 to 20 minutes while heating at a temperature of 160 to 280 ° C. using a biaxial extruder, and then extruded. Next, a molding material can be obtained by pelletizing the extruded magnetic substance-containing polyamide-based resin composition.

  Further, a phenol resin adhesive is applied on the chemically etched slinger and left to stand for 20 to 60 minutes at room temperature to be air-dried, followed by heat treatment at about 120 ° C. for about 30 minutes. A slinger, which is heat-treated and baked with an adhesive, is set in a mold, and insert molding of the plastic magnet material produced as described above is performed using this as a core. After that, the obtained molded body is heated (secondary curing) at about 130 ° C. for about 2 hours, and a plastic magnet and a slinger adhesive are magnetized in multiple poles using a yoke coil. A magnetic encoder can be obtained.

  The magnetic encoder manufactured as described above using the magnet material having the composition of Example 3 to Example 6 does not peel off and fall off from the slinger even under severe use conditions. It will be highly reliable.

  Next, in the magnetic encoder manufactured by insert molding using the slinger as a core according to the present invention, a test was conducted on the adhesion state due to the difference in surface treatment.

(Example 7)
Unevenness was formed by chemically etching the iron oxalate film formed on the surface of SUS430. The arithmetic average height Ra of the unevenness was 0.9 μm, and the maximum height Rz was 4.5 μm. Then, a 30% solid content phenol resin adhesive (Metal Lock N-15 manufactured by Toyo Chemical Laboratory), which is mainly composed of novolak-type phenol resin, was further diluted 3-fold with methyl ethyl ketone and applied to the slinger surface by dipping treatment. . 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. SUS430 plate material baked with this adhesive is set in a mold, and this is used as a core for plastic magnet material (12 nylon anisotropic plastic magnet compound “FEROTOP TP-A27N” made by Toda Kogyo Co., Ltd.) An amount of 75% by volume)) was insert-molded from the inner periphery with a disk gate. A gate cut was performed immediately after molding, and the adhesive was completely cured by secondary heating at 130 ° C. for 1 hour to obtain a test body of Example 7.

(Example 8)
Example 4 was carried out in the same manner as in Example 7, except that the surface of SUS430 was made uneven by shot blasting, the arithmetic average height Ra of the unevenness was 0.8 μm, and the maximum height Rz was 5.0 μm. The test body was obtained.

  Table 2 below shows the results of pulling the hooked portion of the outer periphery of the encoder after curing with pliers.

  As is apparent from Table 3, the unevenness caused by the chemical etching treatment has a shape in which the inside of the recess is widened (FIG. 3), although the surface roughness is hardly different by the unevenness treatment. It can be seen that the adhesive is firmly attached to the metal side.

  Next, several types of adhesives including the adhesive according to the present invention, and differences in initial adhesiveness and saltwater-resistant adhesive based on differences in their usage were tested.

Example 9
Resol type phenolic resin and glycidyl type epoxy resin as the undercoat adhesive on the slinger of SUS430 plate material (width 40mm, length 100mm, thickness 1mm) which roughened the adhesive joint surface with sandpaper and finished the appropriate surface roughness After applying an adhesive containing and for about 30 minutes at room temperature to air dry, a heat treatment was performed at 200 ° C. for 10 minutes. After that, as an overcoat adhesive, an adhesive mainly composed of a resol type phenolic resin (Metaloc N-15 of Toyo Chemical Laboratories) was applied and left to stand at room temperature for about 30 minutes to air dry. Heat treatment was performed at 120 ° C. for 30 minutes, and this adhesive was baked in a semi-cured state.

Thereafter, this SUS430 plate material is set in a mold, and a plastic magnet material (strontium ferrite-containing polyamide resin composition: binder resin is an alloy material of polyamide 12 and a polyamide block copolymer, Insert molding was performed with a content of 75% by volume. However, the size of the plastic magnet to be molded is 20 mm in width, 30 mm in length, and 3 mm in thickness. The portion to be injection-molded on the SUS430 plate, that is, the bonding area between the plastic magnet and the SUS430 plate is 200 mm ² (20 mm × 10 mm). Then, this joined body was heated (secondary curing) at 150 ° C. for 2 hours to obtain a test body of Example 9.

(Example 10)
A test specimen was obtained in the same manner as in Example 9 except that the adhesive mainly composed of a resol type phenol resin used as the topcoat adhesive was TS 1677-13 manufactured by Road Far East.

(Example 11)
An adhesive containing a resol type phenolic resin and a glycidyl type epoxy resin in a slinger made of SUS430 plate (width 40 mm, length 100 mm, thickness 1 mm) roughened with sandpaper and bonded to an appropriate surface. Was applied and allowed to stand for about 30 minutes at room temperature to air dry, followed by heat treatment at 150 ° C. for 30 minutes. This baked SUS430 plate material is set in a mold, and this is used as a core for a plastic magnet material (a strontium ferrite-containing polyamide resin composition. The binder resin is a polymer alloy of polyamide 12 and a polyamide block copolymer; strontium ferrite The content was 75% by volume). However, the size of the plastic magnet to be molded is 20 mm in width, 30 mm in length, and 3 mm in thickness. The portion to be injection-molded on the SUS430 plate, that is, the bonding area between the plastic magnet and the SUS430 plate is 200 mm ² (20 mm × 10 mm). Then, this joined body was heated (secondary curing) at 150 ° C. for 2 hours to obtain a test body of Example 11.

Example 12
The adhesive used is METALOC N-15, a product of Toyo Chemical Laboratory, which is an adhesive mainly composed of a resol-type phenol resin, and heating (baking) processing conditions (processing conditions are 120 ° C. for 30 minutes) Except for differing, the test body was obtained by the same method as (Example 11).

(Example 13)
The adhesive used is TS 1677-13 of Road Far East, which is an adhesive mainly composed of a resol type phenolic resin, except that the heat treatment conditions (treatment conditions are 120 ° C. for 30 minutes) are different. A test specimen was obtained in the same manner as in (Example 11).

  Ten test pieces of the above five types of adhesion test pieces at the initial stage and after immersion in hot water (after immersion in pure at 80 ° C. for 300 hours) are each subjected to a tensile test at a tensile speed of 5 mm / min. The shear bond strength (average value) in the piece was evaluated. The experimental results are shown in Table 4 below.

  From Table 4, an example in which a plastic magnet test piece and a SUS steel plate are formed and bonded by an adhesive layer composed of two layers of an undercoat adhesive excellent in water resistance and an overcoat adhesive excellent in adhesion to a plastic magnet. In Examples 9 and 10, the initial adhesive strength is larger than that in the case where the adhesive containing the phenol resin and the epoxy resin of Example 11 is used alone, while the adhesive mainly containing the phenol resin is used alone. It was found that higher salt water adhesion was secured than in the case of Example 12 and Example 13.

Sectional drawing which shows the rolling bearing unit of 1st Embodiment of this invention. It is sectional drawing which shows the sealing device provided with the magnetic encoder of 1st Embodiment of this invention. It is a perspective view which shows the example by which the multipolar magnetization was carried out in the circumferential direction of the encoder magnet. It is sectional drawing which shows the rolling bearing unit of 2nd Embodiment of this invention. It is sectional drawing which shows the sealing apparatus provided with the magnetic encoder of 2nd Embodiment of this invention. It is a cross-sectional microscope picture which shows the surface of the slinger processed by chemical etching. It is sectional drawing which shows the sealing apparatus provided with the magnetic encoder of 3rd Embodiment of this invention. It is sectional drawing which shows the conventional rolling bearing unit.

Explanation of symbols

2a Wheel support rolling bearing unit 5a Outer ring 7a Hub 8 Stud 10a, 10b Outer ring raceway 11 Coupling flange 12 Mounting flange 14, 14a, 14b Inner ring raceway 15 Small diameter step 16a Inner ring 17a Ball 18 Cage 21a Seal rings 22, 22a, 22b Elastic material 23 Caulking portion 24b Core metal 25 Slinger 26 Magnetic encoder magnetic pole forming ring 27 Magnetic forming ring

Claims (5)

A method of manufacturing a magnetic encoder comprising: a fixing member that can be attached to a rotating body; and a substantially annular magnet portion that is attached to the fixing member and is multipolarly magnetized in the circumferential direction,
A step of insert-molding a magnet material composed of a magnetic powder and a thermoplastic resin composition using the fixing member baked in a semi-cured state as a core; and
Curing the adhesive by secondary heating;
A step of magnetizing the magnet portion in a circumferential direction with multiple poles;
A method of manufacturing a magnetic encoder, comprising:   The method for manufacturing a magnetic encoder according to claim 1, wherein the adhesive contains at least one of a phenol resin and an epoxy resin. The magnet material contains 60-80% by volume of magnetic powder for anisotropy, and polyamide 6, polyamide 12, polyamide 612, polyamide 11, polyphenylene sulfide is used as the thermoplastic resin. A method for manufacturing the magnetic encoder according to claim 1 or 2. 4. The method of manufacturing a magnetic encoder according to claim 1, wherein unevenness is formed on a surface of the fixing member to which the magnet portion is bonded. A method for manufacturing a wheel bearing rolling bearing unit having a magnetic encoder, comprising:
  The said magnetic encoder is manufactured by any one of Claims 1-4, The manufacturing method of the rolling bearing unit for wheel support characterized by the above-mentioned.

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