CN105556249A - Magnetic encoder, and production method therefor - Google Patents

Abstract

The invention provides a magnetic encoder, and a production method therefore. The magnetic encoder is produced by: applying, during insert moulding, an adhesive agent in a hardened state or a cured state so as to not be washed away from a fixed member by a molten substance of a plastic magnet material, said adhesive agent being capable of having a coating state thereof controlled by way of heating; removing from a die, after completion of the insertion moulding, a moulded article for each slinger; and heating said adhesive agent, after completion of injection moulding, to induce adhesion and establish an adhesive bond between a magnet part and the fixed member.

Description

Magnetic coder and manufacture method thereof

Technical field

The manufacture method that the present invention relates to the magnetic coder used in the detection of the rotational speed of rotary body and the magnetic coder utilizing the method to make.

Background technology

In prior art, in the magnetic coder that wheel bearing uses, there is the ferro-gum scrambler employing the magnetic rubber being mixed into magnetic in rubber, with the plastic magnet scrambler be made up of the plastic magnet being mixed into magnetic in the plastic, but both compare, the injection molded of plastic magnet under the state being applied with magnetic field (magnetic forming) is easy, it can thus be appreciated that, with employ identical magnetic use level ferro-gum situation compared with, higher output can not only be obtained, and the magnetic coder of having excellent magnetic properties, and, plastic magnet scrambler is at resistance to environmental reliability (heatproof oxidation performance, water tolerance, oil resistant, resistance to chemical reagents etc.) and mar proof aspect also more excellent than ferro-gum scrambler.

For the above reasons, for the requirement premised on using under the rugged surroundings assuming higher output (high magnetic force) and BRICS etc., compared with ferro-gum scrambler, plastic magnet scrambler is more suitable, can predict, from now on, take above-mentioned requirements as foothold, the increasing market of plastic magnet scrambler expands.

But, as the driving system of automobile, in the plastic magnet scrambler that can be suitable for towards the wheel bearing used under extremely rugged environment in exploitation, one of maximum technical matters is, between plastic magnet and metal fixed part, how to establish the bonding of high reliability.

Before vehicle to life-span, cohesive force between plastic magnet and fixed part must not be had to disappear and plastic magnet from phenomenons such as fixed part come off, the applicant is first in patent documentation 1,2, as the manufacture method of the plastic magnet scrambler of the bonding for accomplished high reliability, establish (the be shaped bonding) method utilizing and the fixed part being coated with cementing agent is in advance formed simultaneously as the insert molding method of core and bondd, overcome above-mentioned problem.

But, manufacture method according to patent documentation 1,2, even if the plastic magnet scrambler having possessed the bonding of high reliability that also can be suitable in the presence of a harsh environment really can be obtained, but this manufacture method is following manufacture method: after the fixed part being coated with cementing agent is in advance placed to mould, the plastic magnet material of high temperature, high pressure is injected in the mould being controlled so as to the temperature expected, further, after injection completes, keep certain hour in this condition, in mould, make plastic magnet and cementing agent carry out bonding react.Therefore, in order to carry out bonding reaction in mould, and comprise technique insert molding body being kept in mould certain hour, therefore the shortening of pitch time has the limit.

Prior art document

Patent documentation

Patent documentation 1: Jap.P. No. 4178412 publication

Patent documentation 2: Jap.P. No. 4189696 publication

Summary of the invention

The technical matters of invention for solving

As mentioned above, in the manufacture method that patent documentation 1,2 relates to, although the product of high-quality can be obtained, in the reduction of production efficiency, i.e. production cost, also has room for improvement.Therefore, the object of the invention is, in the manufacturing process of magnetic coder, maintain the bond state of fixed part and plastic magnet well to guarantee high reliability, and shorten pitch time to enhance productivity, realize the reduction of production cost.

For the technological means of dealing with problems

The present invention is the invention solving above-mentioned problem, provides following the 1st and the 2nd shown manufacture method and magnetic coder.

(1) first manufacture method, it is the manufacture method of the magnetic coder of the rotational speed for detecting rotary body, the fixed part of cementing agent will be coated with in advance as core, insert molding is carried out to the plastic magnet material containing resin and magnetic and by after described fixed part and the magnet part integration that is made up of described plastic magnet material, described magnet part is carried out multipole magnetized at circumferencial direction, the feature of the manufacture method of described magnetic coder is

Described cementing agent can control by heating the cementing agent that it is coated with membrane stage, and, described cementing agent is applied by with following state: when insert molding, the hardening state that can not run off from described fixed part because of the fused mass of described plastic magnet material or solid state

After insert molding completes, from mould, related for formed products ring oiler is taken out together.

(2) second manufacture methods, it is the manufacture method of the magnetic coder of the rotational speed for detecting rotary body, the fixed part of cementing agent will be coated with in advance as core, insert molding is carried out to the plastic magnet material containing resin and magnetic and by after described fixed part and the magnet part integration that is made up of described plastic magnet material, described magnet part is carried out multipole magnetized at circumferencial direction, the feature of the manufacture method of described magnetic coder is

Described cementing agent can control by heating the cementing agent that it is coated with membrane stage, and, after injection molded completes, carry out heating bonding is finished, the adhesive joint of described magnet part and described fixed part is finished.

(3) magnetic coder, is characterized in that, utilizes above-mentioned (1) or the manufacture method described in (2) to manufacture.

Invention effect

The present invention relates to the 1st, in the 2nd manufacture method, adopt and employ and can control by heating the insert molding method that it is coated with the cementing agent of membrane stage, thus compare with existing product, guarantee equal high reliability, and significantly shorten pitch time, therefore, it is possible to realize cost degradation tremendously.Therefore, the magnetic coder utilizing the method to obtain also has high reliability, and low price.

Accompanying drawing explanation

Fig. 1 is the cut-open view of the example that the roller bearing unit possessing magnetic coder is shown.

Fig. 2 is the cut-open view that the packoff possessing magnetic coder is shown.

Fig. 3 illustrates that magnetic pole forms the stereographic map of an example of ring.

Description of reference numerals

2a hub unit bearing (bearing)

5a outer ring (retainer plate)

7a wheel hub (rotating circle)

11 in conjunction with flange

12 mounting flanges

16a inner ring (rotating circle)

17a ball (rolling body)

21a, 21b sealing ring

22a, 22b resilient material

24a, 24b are metal-cored

25 ring oilers (fixed part)

26 magnetic coders

27 magnetic poles form ring (magnet part)

28 sensors

Embodiment

Below, with reference to accompanying drawing, the present invention is described in detail.

Fig. 1 is an example as magnetic coder and the cut-open view of the state loaded in wheel support roller bearing unit 2a is shown, this wheel support with roller bearing unit 2a by the suspension support of independent suspension formula, for supporting non-driving wheel.

In illustrated roller bearing unit 2a, comprise: as the outer ring 5a of retainer plate; With the mounting flange 12 for fixing vehicle wheel (not shown) rotate integrally as rotating the wheel hub 7a and inner ring 16a that enclose (rotary body); Multiple ball 17a, 17a as rolling body of circumferentially arranging between outer ring 5a and wheel hub 7a and inner ring 16 Free-rolling; And magnetic coder 26.

For inner ring 16a outer on the path end difference 15 that the inner end at wheel hub 7a is formed, its inner end is compressed by utilizing calking portion 23, thus be combinedly fixed on wheel hub 7a, calking portion 23 is formed by the inner end radius vector of this wheel hub 7a being filled outward to open.In addition, wheel is freely combined fixing by stud bolt 8 in the outer end of this wheel hub 7a, this stud bolt 8 is arranged at mounting flange 12 circumferential with predetermined space implantation, and this mounting flange 12 is formed in from the outstanding part in the outer end of the outer ring 5a as retainer plate.On the other hand, outer ring 5a utilizes and is formed in freely combining not shown tangle (knuckle) etc. that be fixed on formation draft hitch in conjunction with flange 11 of its outer peripheral face.Between outer ring 5a and wheel hub 7a and inner ring 16a, be configured with at circumferential Free-rolling multiple ball 17a, 17a of being guided by retainer 18.

And, between the both ends inner peripheral surface of outer ring 5a and the inner end outer peripheral face of the pars intermedia outer peripheral face of wheel hub 7a and inner ring 16a, be respectively equipped with sealing ring 21a, 21b.The space and space outerpace that are provided with each ball 17a, 17a, between the inner peripheral surface and the outer peripheral face of wheel hub 7a and inner ring 16a of outer ring 5a, cut off by these each sealing ring 21a, 21b.

Each sealing ring 21a, 21b respectively by utilizing metal-cored 24a, 24 couples of elastic components 22a, 22b strengthen forming, this metal-cored 24a, 24 is by bending by mild steel plate and formed and be circular with cross section L-shaped by set overall.For such each sealing ring 21a, 21b, each metal-cored 24a, 24b are embedded in the both ends of outer ring 5a with interference fit, and the leading section of the sealing lip making each elastic component 22a, 22b form and ring oiler 25 are respectively throughout complete cycle ground sliding contact, this ring oiler 25 is outer is fixed on the pars intermedia outer peripheral face of wheel hub 7a or the inner end outer peripheral face of inner ring 16a.

In addition, as shown in Figure 2, magnetic coder 26 comprises: the ring oiler 25 as fixed part and the formation of the magnetic pole as the magnet part ring 27 at the side of ring oiler 25 one joint.As shown in Figure 3, it is multipole magnets that magnetic pole forms ring 27, is alternately formed with N pole and S pole in its circumference.Further, formed with this magnetic pole faced by ring 27 and be configured with Magnetic Sensor 28 (with reference to Fig. 1).

In addition, the magnetic pole of magnetic coder 26 forms ring 27 and is made up of multipole plastic magnet, and this multipole plastic magnet is formed by magnetic with as the resin combination of its bonding agent.And, this magnetic coder 26 is manufactured as described below, that is: the ring oiler 25 of cementing agent will be coated with in advance as core, and after insert molding is carried out to plastic magnet material, heat, thus the bonding of carrying out cementing agent and plastic magnet is reacted, bonding is between the two completed, then, will obtain adhesive joint thing circumferential carry out multipole magnetized.

, plastic magnet is not limited herein, be made up of the resin combination being major component with magnetic and bonding agent.As the major component of bonding agent, can polyamide series resin be used, specifically, polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 612 etc. can be used.When being equipped on driving wheel hub bearing, substantially can be exposed in external environment condition, the lime chloride being used as Snow Agent likely pours on this plastic magnet with water in the lump, but by the use level of adjustment (increase) magnetic, can guarantee the permanance of necessity and sufficiency, therefore the application of above-mentioned polyamide series resin is not problem completely.Wherein, in above-mentioned polyamide series resin, if apply so-called HighNylon and polyamide 11, polyamide 12, polyamide 612 so be polyamide 410, make terephthalic acid (TPA) and hexane diacid unit carry out the polyamide 6 T/6-6 as semiaromatic polyamide composition, polyamide 6 T/6I, polyamide 6 T/6I/6-6, polyamide 6 T/M-5T, polyamide 9T etc. of part copolymerization, then their water-intake rate is less, therefore resistance to Snow Agent is good, therefore particularly preferably.

As magnetic, the terres rares magnetic powder such as the ferrite such as strontium ferrite, barium ferrite, Nd-Fe-B, samarium-cobalt, samarium-iron can be used.It should be noted that, when employing the magnetic powder of rare earth, compared with ferrite, oxidative resistance is low, therefore, in order to maintain stable magnetic characteristic for a long time, also can the surface-treated layers such as electronickelling, process for electroless nickel plating, epoxy resin film, silicone resin film or fluororesin coating film be set on scrambler surface.

In addition, as magnetic, if consider weatherability, then the ferrite such as strontium ferrite is the most applicable, further, in order to improve ferritic magnetic characteristic, also can be mixed into lanthanum and cobalt etc. or a ferritic part is replaced to the terres rares magnetic powder such as Nd-Fe-B, samarium-cobalt, samarium-iron.

In plastic magnet, the content of magnetic is preferably 40 ~ 80 volume %.When the content of magnetic is lower than 40 volume %, magnetic characteristic is poor, and is difficult to make it multipole magnetized at circumferencial direction with thin space, on the other hand, when being greater than 80 volume %, then resin-bonding dosage is very few, the intensity step-down of magnet entirety, be difficult to be shaped, practicality reduces simultaneously.

In addition, in resin combination, according to object, various adjuvant can be added.Such as, in order to make the reliability of magnetic coder under the situation being applied in-40 DEG C ~ 120 DEG C thermal shocks repeatedly more certain, the compound substance having coordinated the soft composition as impact strength modifying agent in the polyamide series resin as the major component of bonding agent also can be formed in.Polyamide series resin as the major component of bonding agent is generally indefinite is the hard brittle material of intensity difference, but in order to make reliability under above-mentioned harsh temperature environment more certain, the intrinsic flexibility (toughness) of polyamide series resin is necessarily inabundant.In order to ensure higher reliability, the improvement of the flexibility (or low-temperature impact resistance) under indispensable flexibility, particularly low temperature, therefore, in order to realize object of the present invention, the cooperation as the soft composition of the impact strength modifying agent under low temperature (-40 DEG C) becomes extremely important.

As soft composition, can use in its molecular configuration and comprise the thermoplastic elastomer that glass transition temperature is at least the soft chain segment of less than-40 DEG C.As the thermoplastic elastomer that can utilize, there are polystyrene, polyolefin, polyvinyl chloride, Polyester, polyurethane series, polyamide-based, polyolefin and silicone-based, but consider the performance requirement of scrambler, environment for use, more suitably, Polyester and polyamide-based such engineering plastics based thermoplastic elastic body, and, as long as the soft chain segment glass transition temperature less than-40 DEG C of these thermoplastic elastomers.

It should be noted that, as long as this soft chain segment glass transition temperature is less than-40 DEG C, not especially by restrictions such as other character.As the candidate of such soft chain segment, can consider polyester, polyethers, polybutadiene, polyisoprene, polycarbonate and polycaprolactam etc., options is many.Wherein, consider the easy degree this point obtained from market, present situation is, selects the thermoplastic elastomer in soft chain segment with polyester or polyethers to be best suited for.Particularly, consider hydrolytic resistance, the thermoplastic elastomer of the polyether segment can thought containing the latter is more suitable for.In addition, as the concrete example of polyether segment, can enumerate: PolyTHF, polypropyleneoxide, polyethylene oxide or their multipolymer etc.

In addition, as soft composition, dynamic crosslinking type thermoplastic elastomer also can be used.Dynamic crosslinking type thermoplastic elastomer is the polymer alloy comprising thermoplastic resin and rubber, has the shortcoming that makes existing thermoplastic elastomer and oil resistance, a feature that thermotolerance improves.Therefore dynamic crosslinking type thermoplastic elastomer by thermoplastic resin and rubber combination in any are carried out design of material, can have studied various combination.That is, polyolefin, polystyrene, polyamide-based etc. commercially available, such as, the dynamic crosslinking type thermoplastic elastomer etc. comprising polyamide and silicone rubber that hyperalloyactymer, Multibase society made by rikentechnos (strain) that can particularly preferably use polystyrene dynamic crosslinking type elastic body and polyester elastomer, polyurethane elastomer, polyamide elastomer compatible sells.

It should be noted that, the use level of soft composition is 5 ~ 50 quality % relative to resin combination total amount, is preferably 10 ~ 35 quality %.If lower than 5 quality %, then absolute magnitude is very few, the low-temperature pliability of expectation can not be given.In addition, when more than 50 quality %, particularly thermotolerance is insufficient, is not suitable as the purposes of the ferromagnetic material of magnetic coder.

In addition, in resin combination, also thermal stabilizer (heat-resisting processing stabilizers, antioxidant), light stabilizer, charged preventor, plasticiser, inorganic or organic fire-retardant, intensive etc. can suitably be added as required.

Particularly, consider environment for use, preferred interpolation thermal stabilizer, as preferred additive, as amine system antioxidant, have 2, 2, 4-trimethyl-1, amine/ketone system representated by 2-bis-p-dihydroxy-benzene polymkeric substance, p, diallyl amine system representated by p '-dicumyl diphenylamine, and N, the antioxidant that p-phenylenediamine system representated by N '-diphenyl-p-phenylenediamine is such, as phenol system antioxidant, have 2, single phenol system representated by 6-di-tert-butyl-4-methy phenol, with 2, polyphenol system representated by 2 '-di-2-ethylhexylphosphine oxide (4-methyl-6-tert-butylphenol).And on the other hand, the quinhydrones system antioxidant that 2,5-di-tert-butyl hydroquinone is so also can be used.

And, in resin combination, also also can use peroxide-decomposing type antioxidant (secondary antioxidant) with above-mentioned amine system, phenol system together with the antioxidant of quinhydrones system.As secondary antioxidant, the phosphorus system secondary antioxidant that the sulphur system secondary antioxidant that 2-mercaptobenzimidazole can be used such, three (nonyl phenyl) phosphite are such.

It should be noted that, the use level of thermal stabilizer is preferably about 0.1 ~ 3 quality % relative to adhesive resin, but according to kind, maybe can not produce in dysgenic scope to the physical property of resin not producing halation, also can use above-mentioned above amount.

Contain resin combination to the magnetic containing mentioned component and carry out granulating, obtaining can for the plastic magnet material of insert molding.Now, use biaxial extruder, kneader or internal mixture etc., adhesive resin, soft composition, various adjuvant are mixed, makes resin combination, and this resin combination is extruded, carry out granulating.It should be noted that, mix that at the temperature of 160 DEG C ~ 280 DEG C, carry out 1 minute ~ 20 minutes be suitable.Then, use same mixing machine, after resin composition pellet and magnetic mixing, extrude, resin combination is contained to magnetic and carries out granulating.It should be noted that, it is also suitable that mixing now carries out 1 minute ~ 20 minutes at the temperature of 160 DEG C ~ 280 DEG C.

As mentioned above, at patent documentation 1, in 2 such manufacture methods, performance and excellent in te pins of durability, the plastic magnet scrambler of the high reliability that also can be suitable under severe running car system environment can be obtained, but, to be coated with after the fixed part after cementing agent (ring oiler 25) is placed to mould in advance, carry out the injection molded of plastic magnet material, further, after injection moulding completes, keep certain hour in such a state, in mould, make the bonding of plastic magnet and cementing agent react carry out to a certain degree, therefore the shortening of pitch time has the limit.

Consider above-mentioned problem, inventor is in order to establish the new manufacture method of the plastic magnet scrambler of the cost degradation realizing the high reliability above on an equal basis with existing product and be much better than existing product, repeatedly conduct in-depth research, result new discovery can cancel the cementing agent insert molding body in existing autofrettage being kept in mould the technique of certain hour, further, it is suitably applied, specify that (namely can control it is coated with membrane stage further, realize sclerosis or the solid state of immobilising level during insert molding, on the other hand, carry out fast and complete bonding during heating after forming, realize the control of sclerosis or the such painting membrane stage of solid state completely) cementing agent treatment conditions and be coated with the variation relation of membrane stage, complete the present invention.It should be noted that, bondd and referred to, magnetic coder achieves can guarantee that under practical service environment the magnetic pole of sufficient reliability forms the cohesive strength of ring 27, the state of adhesive durability.

That is, in the present invention, use and can control by heating the cementing agent that it is coated with membrane stage.In more detail, using makes the painting membrane stage after coating become the cementing agent of the state of expectation according to heat treated condition (temperature, time), namely, the cementing agent used is: when insert molding, the molten plastic ferromagnetic material injected with high temperature, high pressure also has the solid state (manufacture method of the 1st) of the level that can not flow, or complete bonding during heating after forming, and become sclerosis or solid state (manufacture method of the 2nd).

As cementing agent, meet selected condition if above-mentioned, then without any other restriction, can suitably use thermmohardening type cementing agent and hot-melt type adhesive.It should be noted that, as thermmohardening type cementing agent, epoxy resin cementing agent, silicone-based cementing agent, urethane resin system cementing agent can be used.In addition, in above-mentioned thermmohardening type cementing agent, also containing normal temperature hardened epoxy resin cementing agent, silicone-based cementing agent, the urethane resin system cementing agent that at room temperature harden, also suitably can use them.In addition, as hot-melt adhesive (hot-meltadhesive, hot melt adhesive), can enumerate: polyurethane series hot-melt adhesive, polyamide-based hot-melt adhesive, Polyester hot-melt adhesive, modified olefin system hot-melt adhesive, silicone-based hot-melt adhesive, epoxy hot-melt adhesive, phenol resin system hot-melt adhesive etc., also can use and they are carried out to suitable modification, such as implement to give the modification of thermosetting etc., and use.

Hot melt system cementing agent is owing to, by place at normal temperatures thus coated side is solidified and formed film, therefore can not to flow out from ring oiler 25 when insert molding after applying with molten condition in heating.Then, heat once again, thus sclerous reaction is carried out, harden completely.Wherein, the bonding agent that hot melt system cementing agent needs are suitable for is: except imparting thermosetting modification product, also want softening point at least more than 120 DEG C.This is because, fully take into account magnetic coder be exposed on the atmosphere of 120 DEG C under situation, such as, consider following situation: when under the situation that the thermal shock being repeatedly exposed on applying-40 DEG C ~ 120 DEG C is such, for the hot-melt adhesive that softening point is less than 120 DEG C, due to the impact that cementing agent during high temperature is softening, magnetic pole forms ring 27 and moves from ring oiler 25, and comes off.

And, in above-mentioned cementing agent, about thermmohardening type epoxy resin cementing agent and thermmohardening type silicone-based cementing agent, thermmohardening type polyurethane resin system cementing agent, particularly preferably use solvent-free type.In a binder, have and be dissolved or dispersed in the cementing agent used under the state in organic solvent, but by using solvent-free cementing agent thus without the need for the process of machine solvent, from environmentally considering, be preferred.

As the painting method to ring oiler 25 coated with adhesive, when the viscosity of hot melt system cementing agent, cementing agent is higher, extrude cementing agent from the discharge opening of nozzle, be directly coated in the magnet composition surface of ring oiler 25.In addition, when the binder solution making cementing agent be dissolved or dispersed in organic solvent, ring oiler 25 is immersed in binder solution, after taking-up, carries out drying, removing organic solvent.

It should be noted that, for the bonding surface of ring oiler 25, more firm in order to make with the bonding of plastic magnet, preferably utilize mechanical treatment, the chemical method for etching etc. such as sandblasting to carry out surface roughening.

And, in the manufacture method of the 1st of the present invention, to the ring oiler 25 of the film of above-mentioned cementing agent be formed with as core, plastic magnet material injection is shaped by the face after being coated with cementing agent, but now, cementing agent film becomes sclerosis or is solidified into the state of the degree that can not flow out from the coated side of ring oiler 25 because of the molten plastic ferromagnetic material of injection.In order to form such sclerosis or the state of solidification, preferably heat according to the kind of cementing agent.Such as, for thermmohardening type epoxy resin cementing agent, at 50 ~ 60 DEG C, heat 40 minutes ~ 1 hours, for thermmohardening type silicone-based bonding, at 100 ~ 120 DEG C, heat 30 minutes ~ 1 hours, be formed as semi-hardened state.In addition, do not heat, also can by placing at normal temperatures and making it harden or solidify.In addition, for hot melt system cementing agent, place at normal temperatures thus curing of coating after coating as described above, therefore, it is possible to directly use.Place according to such normal temperature, there is no need for the equipment heated, can production cost be reduced.

This insert molding is only by plastic magnet material forming on ring oiler, rapid in mould taking-up ring oiler 25 after being shaped.During insert molding, although also consider that the heat of the fused mass of plastic magnet material makes the sclerosis of cementing agent carry out a part, but cementing agent hardens in fact hardly, the molding (magnetic pole forms ring 27) of plastic magnet material becomes the state being temporarily retained as and can not coming off from ring oiler 25.

Then, the manufacture method as the 2nd, be heated to more than the temperature of the reaction acceleration making cementing agent, bond, and bonding is completed, thus ring oiler 25 and magnetic pole formation ring 27 are firmly adhered.It should be noted that, as heating means, from the viewpoint of can single treatment a large amount of precursor, preferably use heating furnace.

It should be noted that, in insert molding, preferably use the injection molding machine of diaphragm gate mode.Magnetic material after melting is extended to plate-like, then flow into the mould of the part being equivalent to internal diameter thickness portion, thus the lepidiod magnetic powder wherein contained is relative to face orientation abreast.Particularly, the orientation of the inside diameter detected by rotation sensor near internal diameter thickness portion and the part between outer diameter part is higher, is closely oriented to the axle anisotropy of thickness direction.In addition, during shaping, if apply magnetic field (magnetic forming) at thickness direction to mould, then anisotropy is closer to perfection.On the other hand, even if when adopting side gate when carrying out magnetic forming, at slow trend solid state in the process that the viscosity of the magnetic material of melting increases gradually, it is difficult for making the orientation of welding seam part carry out anisotropisation completely, therefore, lower and the welding seam part that physical strength is lower in magnetic signature, long use likely causes be full of cracks etc. occurs, and is not preferred.

Magnetic forming is: after being filled with plastic magnet material in a mold, and when cooling in a mold, demagnetize in the rightabout magnetic field of direction of magnetization.Then, removing gate part, then after making cementing agent harden completely, uses the demagnetizers such as oil-filled condenser type (OilCapacitorType), demagnetizes further, until below 2mT, be more preferably the magnetic flux density of below 1mT.

Then, carrying out gate cutting, in order to make cementing agent harden completely, heating certain hour at a certain temperature with calibration cell etc.According to circumstances, the short time heating under the high temperature such as high-frequency heating can also be carried out.

Like this, manufacturing method according to the invention, after the plastic magnet material to ring oiler 25 insert molding after being coated with cementing agent, does not need to make bonding carry out and keeps, significantly shortening pitch time.In addition, the process for making bonding finish also can be carried out with the heating furnace that can carry out a large amount of process.Therefore, production efficiency improves, and realizes the reduction of production cost.

Then, after bonding being finished carrying out heating, using deflection coil (yokecoil), ring 27 being formed to magnetic pole and carries out multipole magnetized, obtaining magnetic coder.Number of poles is 70 ~ 130 ultra-Left right sides, is preferably 90 ~ 120 poles.When number of poles is lower than 70 pole, number of poles is very few and be difficult to detect rotation number accurately.On the other hand, when number of poles is more than 130 pole, each spacing becomes too small, and be difficult to single interval error to suppress less, practicality is low.

Embodiment

Below, enumerate embodiment and come further that the present invention will be described, but the present invention is not subject to any restriction because of these embodiments.

(embodiment 1 ~ 5, comparative example 1)

(making of test body)

First, in biaxial extruder, drop into polyamide 12, the soft composition (Thermoplastic polyamide elastomer) of 30 quality % of resin combination total amount, the thermal stabilizer (N of 0.5 quality %, N '-diphenyl-p-phenylenediamine), mix, obtain resin combination.Mixing carries out 5 minutes at 250 DEG C.Then, usual way is utilized to carry out granulating to resin combination.

Then, in the particle of resin combination, drop into ferrite magnetic, use biaxial extruder, mix 10 minutes at 250 DEG C after, extrude.It should be noted that, magnetic is 60 volume % of plastic magnet material.Then, the magnetic after extruding this contains resin combination and carries out granulating.

In addition, prepare the stainless steel ring oiler (with reference to Fig. 2) of cross section L-shaped, utilize sandblasting to carry out roughened to adhesive surface.

Then, at the adhesive surface of above-mentioned ring oiler, the cementing agent of coating shown in table 1, heats with the temperature and time of token, makes it harden.

Then, the ring oiler being coated with cementing agent is placed on the mould of injection molding machine, uses above-mentioned magnetic to contain the particle of resin combination, enter insert molding.Then, after insert molding completes, take out together from the related ring oiler of mould, and collecting is to heating furnace, heats 1 hour at 150 DEG C, bonding is finished.Then, take out from heating furnace, after cooling, use deflection coil, multipole is magnetized, makes magnetic coder test body.

(resistance to sudden heating test)

For the magnetic coder test body of embodiment and comparative example, implement thermal shock test repeatedly.Test condition is: keep remaining 1 circulation with (at-40 DEG C 30 minutes) with (at 120 DEG C 30 minutes), carry out 1000 circulations.Then, after 1000 circulations, visual assessment outward appearance, and that evaluates after disbonded test (forcible separation method in plastic magnet portion) is damage state based.Result is recorded in table 1 in the lump, in ocular estimate, without fragment, unchanged without gap, flawless and shape of product time, as well, in table, token is " 〇 ", and when there being fragment etc., as bad, in table, token is "×".In addition, in disbonded test, when magnet segment there occurs breakage, be judged as that cohesive strength is good, in table, token is " 〇 ", unbroken situation is judged as imperfect bonding, and in table, token is "×".

Table 1

※ (120 DEG C, 30 minutes)+(-40 DEG C, 30 minutes) are 1 circulation, carry out 1000 circulations

As shown in table 1, based in various embodiments of the present invention, outward appearance is good, even if in disbonded test, also obtains firmly cohesive strength.On the other hand, in comparative example 1, although employ hot melt system cementing agent, but at fusing point lower than 120 DEG C, and when applying the thermal shock repeatedly of-40 DEG C ~ 120 DEG C, because ring oiler is different with the linear expansion coefficient of plastic magnet, and stress is applied to binding part, when fusing point is lower than 120 DEG C as previously mentioned, binding part there occurs softening, when high temperature, (120 DEG C) there occurs deformation because of the stress produced at binding part, consequently, plastic magnet moves (having change of shape) from ring oiler, further, due to its impact, and cohesive strength is also not enough in disbonded test.

Describe the present invention in detail or with reference to particular implementation, but those skilled in the art understand, can carry out various change and correction without departing from the spirit and scope of the present invention.

The Japanese patent application (special Willing 2013-195854) that the application proposed based on September 20th, 2013, and its content is incorporated into this, as a reference.

Industrial applicability

According to the present invention, can pitch time be shortened and manufacture the magnetic coder used in wheel bearing expeditiously, the production cost of magnetic coder can be reduced.

Claims (3)

1. the manufacture method of a magnetic coder, it is the manufacture method of the magnetic coder of the rotational speed for detecting rotary body, the fixed part of cementing agent will be coated with in advance as core, insert molding is carried out to the plastic magnet material containing resin and magnetic and by after described fixed part and the magnet part integration that is made up of described plastic magnet material, described magnet part is carried out multipole magnetized at circumferencial direction, the feature of the manufacture method of described magnetic coder is

Described cementing agent can control by heating the cementing agent that it is coated with membrane stage, and, described cementing agent is applied by with following state: when insert molding, the hardening state that can not run off from described fixed part because of the fused mass of described plastic magnet material or solid state, after insert molding completes, from mould, related for formed products ring oiler is taken out together.

2. the manufacture method of a magnetic coder, it is the manufacture method of the magnetic coder of the rotational speed for detecting rotary body, the fixed part of cementing agent will be coated with in advance as core, insert molding is carried out to the plastic magnet material containing resin and magnetic and by after described fixed part and the magnet part integration that is made up of described plastic magnet material, described magnet part is carried out multipole magnetized at circumferencial direction, the feature of the manufacture method of described magnetic coder is

Described cementing agent can control by heating the cementing agent that it is coated with membrane stage, and, after injection molded completes, carry out heating bonding is finished, the adhesive joint of described magnet part and described fixed part is finished.

3. a magnetic coder, is characterized in that, utilizes the manufacture method described in claim 1 or 2 to manufacture.