JP6544456B2 - Composite member having annular bonded magnet and method of manufacturing the same - Google Patents

Description

The present invention relates to a composite member provided with an annular bonded magnet and a method of manufacturing the same.

For example, as a driving source of a fuel pump in a car, a motorcycle, etc., a rotor provided with an annular permanent magnet as shown in Patent Document 1, for example, is known. This component is configured by attaching a magnet to a rotating body that is a metal base. As a mounting method, there is a method of utilizing adhesive force such as adhesion or a method of utilizing mechanical fitting force such as shrink fitting or caulking. For relatively small parts, a method of integrally molding a bond magnet on a metal member is adopted mainly from the viewpoint of cost reduction. However, the bond magnet may be broken due to the difference in the coefficient of linear expansion of the metal member and the bond magnet material during the cooling process during the manufacturing process, the operation of a car or a motorcycle, or storage in a cold region is there. Therefore, a composite member excellent in cooling and heating cycles is required, and in Patent Document 1, the annular permanent magnet is annular by injection molding the metal member, the magnet powder, the thermoplastic resin, and the thermoplastic elastomer. A composite member integrally molded on the outer periphery of a metal member has been proposed.

According to Patent Document 2, when bonding a plurality of sintered magnets to the outer surface of a metal rotor core, the thermal stress between the rotor core and the magnet can be reduced by opening the gap between the magnetic pole and the magnetic pole. There is a description of

Patent Document 3 describes that a metal rotor core and a magnet are joined by solder and that a plurality of slit-like concave portions are provided on the surface of the rotor core for the purpose of relieving thermal stress.

Patent Document 4 describes that when forming an anisotropic bond magnet around a metal shaft, it is recommended that the inter-pole portion, that is, the switching portion of the magnetic pole and the weld portion do not coincide.

Patent Document 5 describes that flexibility can be improved by mixing a bisunsaturated fatty acid amide in a polyamide, which is a base resin most used in bonded magnets, and the thermal shock resistance of the molded article can be improved.

In Patent Document 6, there is a description that molding shrinkage cracking is improved by mixing liquid rubber into polyamide, which is also a base resin.

In Patent Document 7, there is a description that it is possible to avoid cracking of a molded body by combining materials having an aspect ratio appropriately selected.

In Patent Document 8, when the bonded magnet is integrally formed on the outer periphery of the rotor, an intermediate layer is provided on the rotor and the bonded magnet, and a molded shrinkage crack is formed by forming a bonded magnet composed of a material having a large bending strain. There is a statement that cold cycle cracking can be avoided.

According to these conventional methods, it is necessary to newly consider the resin composition or significantly review the magnet particle composition as a countermeasure against cracking, and for this purpose it is necessary not only to increase costs but also to verify characteristics other than cracking. was there. In other words, there is a demand to improve only the behavior of the crack while maintaining the magnet characteristics represented by the magnetic characteristics or maintaining the tensile characteristics and the adhesive strength by using the current material as it is.

On the other hand, Patent Document 9 discloses a composite material including a soft magnetic powder, a filler having an outer peripheral layer containing an organic matter on the surface of rubber, and a resin portion containing the soft magnetic powder and the filler in a dispersed state. It is done. Although the filler containing the rubber is dispersed, it is effective in suppressing the extension caused by the micro crack, but in order to be compatible with the resin, the filler itself needs to be separately formulated such as surface treatment. Further, as in the present invention, in the case of an annular bonded magnet formed by integral molding with a metal member, stress is applied to the resin due to the difference in linear expansion coefficient at the time of thermal shock, so that the resin is compatible with the matrix resin. It is difficult to obtain sufficient effect in terms of absorbing the stress by the method of dispersing the rubber by

Unexamined-Japanese-Patent No. 2016-101062 JP 2002-78257 A Japanese Patent Application Publication No. 2016-533148 gazette JP, 2008-172965, A JP, 2006-41116, A Japanese Patent Laid-Open No. 6-287445 JP, 2005-72240, A JP 2005-151757 A JP, 2016-143827, A

The present invention provides a composite member having an annular bonded magnet excellent in thermal shock resistance and a method of manufacturing the same.

The composite member according to one aspect of the present invention is
A composite member comprising a substantially cylindrical or substantially annular metal member and an annular bonded magnet provided on the outer periphery of the metal member, wherein the annular bonded magnet includes a thermoplastic resin, magnetic particles, and rubber particles. It is characterized by

According to another aspect of the present invention, there is provided a method of producing the composite member,
Kneading the thermoplastic resin and the magnetic particles to obtain a compound;
It is characterized by including a step of integrally molding the compound and the rubber particles with a substantially cylindrical or substantially annular metal member.

According to the above aspect, it is possible to provide a composite member having an annular bonded magnet excellent in thermal shock resistance and a method of manufacturing the same.

It is a figure which shows the cross-sectional photograph of the bonded magnet concerning 1 aspect of this invention. FIG. 2 is a schematic view of a bonded magnet including rubber magnet particles according to one embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described. However, the embodiments shown below are for embodying the technical idea of the present invention, and the present invention is not specified to the following. In the present specification, when a plurality of substances corresponding to each component are present in the composition, the content of each component in the composition is the total of the plurality of substances present in the composition unless otherwise specified. Means quantity.

(Composite member)
The composite member of the present invention is a composite member including a substantially cylindrical or substantially annular metal member and an annular bonded magnet provided on the outer periphery of the metal member, wherein the annular bonded magnet is a thermoplastic resin, It contains magnetic particles and rubber particles.

In a composite member provided with an annular bonded magnet provided on the outer periphery of a conventional metal member, a stress is applied to the resin due to the difference in linear expansion coefficient at the time of thermal shock, and thus the bonded magnet is likely to be cracked. On the other hand, in the present embodiment, it is considered that the rubber elasticity is sufficiently exhibited by the presence of the elastic member as rubber particles, and the stress of expansion and contraction during the thermal cycle can be sufficiently relieved.

The shape of the metal member is not limited as long as it is substantially cylindrical or substantially annular. The outer diameter of the substantially cylindrical or substantially annular metal member is preferably 5 mm or more and 100 mm or less, and the height is preferably 1 mm or more and 30 mm or less. The metal of the metal member is not particularly limited as long as it can be a yoke.

The shape of the composite member provided with the annular bonded magnet is also not limited as long as it is substantially cylindrical or substantially annular. The outer diameter is preferably 6 mm or more and 150 mm or less, and the height is preferably 1 mm or more and 30 mm or less.

The thermoplastic resin is not particularly limited, and examples thereof include polypropylene, polyethylene, polyvinyl chloride, polyester, polyamide, polycarbonate, polyphenylene sulfide and acrylic resin. Among them, polyamide, particularly polyamide 12 is preferable. The polyamide 12 has a relatively low melting point, a low water absorption rate, and is a crystalline resin so that the moldability is good. Moreover, it is also possible to mix and use these suitably.

The annular bonded magnet preferably further contains a thermoplastic elastomer. By including the thermoplastic elastomer, the initial strength can be improved without impairing the flowability. Examples of the thermoplastic elastomer include polystyrenes, polyolefins, polyesters, polyurethanes and polyamides. Moreover, you may mix and use these suitably. Among these, polyamide-based thermoplastic elastomers which are excellent in chemical resistance are preferable.

The annular bonded magnet may further contain an antioxidant such as a phosphorus-based antioxidant. By including the phosphorus-based antioxidant, the change in strength with time can be reduced even when the composite member is exposed to high temperatures. Examples of phosphorus-based antioxidants include tris (2,4-di-tert-butylphenyl) phosphite and the like.

Magnetic particles include ferrite-based and rare earth-based Nd--Fe--B-based, Sm--Co-based, and Sm--Fe--N based. Among them, it is preferable to use Sm-Fe-N system. Sm-Fe-N system is generally represented by the _Sm 2 _Fe 17 _{N 3.} The Sm-Fe-N system has a stronger magnetic force than a ferrite system, and can generate a high magnetic force even with a relatively small amount. In addition, Sm-Fe-N is smaller in particle diameter than other rare earths such as Nd-Fe-B and Sm-Co, and is suitable as a filler for base resin, and resistant to rusting. It has the feature of

The magnetic particles may be either anisotropic or isotropic or both. From the viewpoint of obtaining stronger magnetic properties, anisotropic particles (anisotropic magnetic particles) are preferred. Specifically, Sm-Fe-N-based magnetic particles (anisotropic Sm-Fe-N-based magnetic particles) having anisotropy are preferable. When an Sm—Fe—N based magnetic particle is used as the magnetic particle, the magnetic particle has a strong magnetic force, so that the magnetic particle can be made more excellent.

10 micrometers or less are preferable and, as for the average particle diameter of a magnetic particle, 1 micrometer or more and 5 micrometers or less are more preferable. If it is 10 μm or less, uneven parts, cracks and the like do not easily occur on the surface of the product, and the appearance can be excellent. Further, cost reduction can be achieved. If the average particle size is larger than 10 μm, irregularities and cracks may be generated on the surface of the product and the appearance may be deteriorated. On the other hand, when the average particle diameter is smaller than 1 μm, the cost of the magnetic particles is increased, which is not preferable from the viewpoint of cost reduction.

The rubber particles may be commercially available products, or may be used after crosslinking and grinding a rubber material. The raw material for the rubber is not particularly limited, but from the viewpoint of thermal shock resistance, rubber having heat resistance of 120 ° C. or more and cold resistance of −40 ° C. or less is preferable, for example, silicone rubber (silicone raw rubber), fluoro rubber, ethylene acetic acid Vinyl rubber etc. are mentioned. Silicone rubber is particularly preferred in view of moderate flexibility and chemical stability, heat resistance and cold resistance.

The rubber particles are preferably rubber magnet particles containing at least a part of magnetic particles in view of magnetic flux density (see FIG. 2). The magnetic particles described above can be used as the magnetic particles. The content of the magnetic particles in the rubber magnet particles is preferably 50% by mass to 99% by mass, and more preferably 80% by mass to 98% by mass from the viewpoint of obtaining high magnetic properties.

The average particle diameter of the rubber particles is determined as a particle diameter corresponding to 50% of accumulation from the small diameter side in a volume-based cumulative particle size distribution measured under dry conditions using a laser diffraction type particle size distribution measuring device. The average particle diameter of the rubber particles is preferably more than 0.7 μm and less than 1 mm, more preferably 2 μm or more and 900 μm or less from the viewpoint of thermal shock resistance, and particularly preferably 11 μm or more and 500 μm or less. In the case of rubber magnet particles containing magnetic particles, the rubber particles preferably have a diameter of more than 0.7 μm and less than 1 mm, preferably 50 μm to 900 μm, and particularly preferably 100 μm to 800 μm. .

The content of the magnetic particles in the annular bonded magnet is preferably 80% by mass or more and 95% by mass or less, and more preferably 90% by mass or more and less than 95% by mass from the viewpoint of obtaining high magnetic properties. The content of the thermoplastic resin in the annular bonded magnet is preferably 3% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 15% by mass or less from the viewpoint of securing fluidity. Furthermore, when the thermoplastic elastomer is contained, the content of the thermoplastic elastomer in the annular bonded magnet is preferably such that the mass ratio of the thermoplastic resin to the thermoplastic elastomer is in the range of 90:10 to 50:50, The range of 90:10 to 70:30 is more preferable from the point of impact resistance. Furthermore, in the case where a phosphorus-based antioxidant is contained, the content of the phosphorus-based antioxidant in the annular bonded magnet is preferably 0.1% by mass or more and 2% by mass or less. The content of the rubber particles in the annular bonded magnet is preferably 0.3% by mass or more and 10% by mass or less, and preferably 0.5% by mass or more and 5.5% by mass or less from the viewpoint of thermal shock resistance. Here, when the rubber particles do not contain a magnetic material, 0.3% by mass or more and 1.0% by mass or less is more preferable, and when the rubber particles are rubber magnet particles containing a magnetic material, 0.3% by mass or more and 10% by mass % Or less is more preferable.

(Method of manufacturing composite member)
The method for producing a composite member according to the present invention comprises the steps of kneading a thermoplastic resin and magnetic particles to obtain a compound, and integrally molding the compound and rubber particles with a substantially cylindrical or substantially annular metal member. It is characterized by including.

In this embodiment, a compound containing a thermoplastic resin and magnetic particles is prepared separately from the rubber particles. When the rubber particles are kneaded together with the thermoplastic resin and the magnetic particles, heat is applied to the rubber particles both during compounding and during integral molding, so that the elasticity and strength of the rubber particles may be reduced. In addition, since the measuring torque at the time of molding is increased, it is necessary to increase the molding temperature, and the molding temperature is increased to cause deterioration of the thermoplastic resin, which may lower the thermal shock resistance. However, in the case of this embodiment, since the heat is applied to the rubber particles only at the time of integral molding, the characteristics of the rubber particles are hardly deteriorated, and the elasticity and the strength of the rubber particles are maintained in the finally obtained composite member. it can.

(Preparation of compound)
In the step of kneading the thermoplastic resin and the magnetic particles to obtain a compound, the thermoplastic resin and the magnetic particles are sufficiently kneaded, and the resulting kneaded product is fed into a kneader such as a single-screw kneader or a twin-screw kneader. After cooling, it can be obtained by cutting to an appropriate size. Here, the thermoplastic resin and the magnetic particles are as described above.

An antioxidant such as a thermoplastic elastomer and a phosphorus-based antioxidant can be simultaneously kneaded together with the thermoplastic resin and the magnetic particles.

80 mass% or more and 95 mass% or less are preferable, and, as for content of the magnetic particle in a compound, 90 mass% or more and 95 mass or less are more preferable from the point which acquires a high magnetic characteristic. On the other hand, the content of the thermoplastic resin in the compound is preferably 3% by mass to 20% by mass, and more preferably 5% by mass to 15% by mass from the viewpoint of securing fluidity. Furthermore, when the thermoplastic elastomer is contained, the mass ratio of the thermoplastic resin to the thermoplastic elastomer is preferably in the range of 90:10 to 50:50, and from the point of impact resistance, the range of 90:10 to 70:30 is More preferable. Furthermore, when it contains phosphorus antioxidant, 0.1 mass% or more and 2 mass% or less of content of phosphorus antioxidant in a compound are preferable.

(Preparation of rubber particles)
Commercially available rubber particles may be used. In the case of producing rubber particles, a rubber raw material and a rubber raw material are combined with a vulcanizing agent such as a mixing roll, a kneader or a Banbury mixer, and a vulcanizing agent and a crosslinking agent are appropriately mixed. Input and obtain a string-like molded article. Subsequently, these molded articles are heat-cured as necessary, cooled, and then crushed to a desired size to obtain rubber particles.

From the viewpoint of magnetic flux density, it is preferable that at least a part of the rubber particles be rubber magnet particles including magnetic particles. The rubber magnet particles are prepared by combining the magnetic particles, the rubber raw material and the rubber raw material with a vulcanizing agent such as a mixing roll, a kneader or a Banbury mixer, and appropriately vulcanizing the vulcanizing agent and the crosslinking agent. It is put into a machine to obtain a string-like molded article. Subsequently, these molded articles are heat-cured as necessary, cooled, and then crushed to a desired size to obtain rubber magnet particles. The magnetic particles and the rubber material are as described above. The rubber magnet particle in which at least a part of the rubber particle contains a magnetic particle means that the rubber particle may be used by mixing the rubber magnet particle and the rubber particle not containing a magnetic material.

(Molding process)
In the step of integrally molding the compound and the rubber particles with the substantially cylindrical or substantially annular metal member, the substantially cylindrical or substantially annular metal member is disposed in the mold of the injection molding machine, and the compound and the rubber particles are formed. Obtained by injection molding into an injection molding machine.

The mass ratio of the rubber particles to the compound is not particularly limited, but 0.3 to 10 parts by mass is preferable with respect to 100 parts by mass of the compound, and 0.5 to 5.5 parts by mass is more preferable. . When the amount is less than 0.3 parts by mass, the thermal shock resistance is insufficient, and when the amount is more than 10 parts by mass, the magnetic flux density tends to be reduced. Here, when the rubber particles do not contain magnetic particles, the rubber particles are more preferably 0.3 parts by mass or more and 1.0 parts by mass or less with respect to 100 parts by mass of the compound, and the rubber particles contain magnetic particles In the case of, 0.3 to 10 parts by mass is more preferable.

The composite member of the present invention can be used as a drive source of a fuel pump in a car, a two-wheeled motor vehicle, etc., for a rotor or the like provided with an annular permanent magnet.

Examples according to the present invention will be specifically described below. The average particle size is determined by measuring the cumulative particle size distribution based on volume using a laser diffraction type particle size distribution measuring device (HELOS & RODOS manufactured by Nippon Laser Co., Ltd.) and determining the particle size corresponding to the cumulative 50% from the small diameter side. The

The following materials were used in the examples.
Magnetic particles: anisotropic Sm-Fe-N system (average particle size 3 μm)
Thermoplastic resin: Polyamide 12
Rubber particles A: Silicone rubber fine particles Tospearl 120 (average particle diameter 2 μm) manufactured by Momentive Performance Materials
Rubber particles B: Silicone rubber fine particles Tospearl 145 (average particle diameter 4.5 μm) manufactured by Momentive Performance Materials
Rubber particle C: Silicone rubber fine particle Tospearl 1110 (average particle diameter 11 μm) manufactured by Momentive Performance Materials
Rubber particles D: Silicone rubber fine particles Tospearl XC99-A8808 (average particle diameter 0.7 μm) manufactured by Momentive Performance Materials

Example 1
Sm-Fe-N based magnetic materials were surface-treated with ethyl silicate and a silane coupling agent. 91% by mass of the surface-treated Sm-Fe-N-based magnetic material and 9% by mass of polyamide 12 are mixed by a mixer. The obtained mixed powder was kneaded at 220 ° C. using a twin-screw kneader, and after cooling, was cut into a suitable size to obtain a pellet-like compound.

0.5 parts by mass of rubber particles A was introduced into an injection molding machine with respect to 100 parts by mass of the compound. Insert an annular metal member (outside diameter φ 14 mm × height 20 mm) into the mold, and injection-mold the compound and rubber particles in one piece with the metal member in the mold cavity surrounding the outer periphery of the metal member Bonded magnets were formed on the outer periphery of the metal member. The dimensions of the composite member were 21 mm in outer diameter, and during injection molding, molding was performed while applying magnetic field orientation in the radial direction to the annular bonded magnet after molding.

(Example 2)
A composite member was obtained in the same manner as in Example 1 except that rubber particles B were used instead of the rubber particles A.

(Example 3)
A composite member was obtained in the same manner as in Example 1 except that rubber particles C were used instead of the rubber particles A.

(Example 4)
A composite member was obtained in the same manner as in Example 1 except that rubber particles D were used instead of the rubber particles A.

(Comparative example 1)
A composite member was obtained in the same manner as in Example 1 except that rubber particles were not used.

<Evaluation 1: Thermal shock test>
For each 10 composite members, 32 cycles of thermal shock with one cycle of "-40 ° C (15 minutes), 160 ° C (2 hours), time to reach 160 ° C or -40 ° C by damper switching: 1 minute" The test was done.
In this test, an accelerated aging test was conducted. Actual use environment-It was assumed whether a crack was confirmed by 500 cycles with respect to -40 degreeC to 120 degreeC in that case. According to the 10 ° C. double speed law, in this test, acceleration degradation is performed at a speed of 2 4. From 500 cycles ÷ 2 of the fourth power = 31.25, in this test, the appearance of the rotor was checked after 32 cycles, and the number of cracks not counted was counted. The obtained results are shown in Table 1.

<Evaluation 2: Magnetic flux density Br>
A cylindrical bonded magnet having a diameter of 10 mm and a height of 7 mm was manufactured using the compound and rubber particles used in each of the examples and the comparative examples. The magnetic flux density Br was measured by a BH curve tracer (manufactured by Riken Denshi). Table 1 shows the results of relative comparison with the magnetic flux density Br measured in Comparative Example 1 as 100.

From Table 1, in comparison with Comparative Example 1, it was confirmed that the thermal shock resistance is improved while the lowering of the magnetic flux density Br is suppressed by containing the rubber particles in Examples 1-4.

(Example 5)
A compound was prepared in the same manner as Example 1. Sm-Fe-N magnetism which surface-treated with 0.1 mass% of addition type vulcanizing agents, 0.4 mass% of crosslinking agents, 22 mass% of silicone raw rubber (cold resistance-120 degrees C, heat resistance 280 degrees C) 77.5% by weight of the material was compounded and uniformly mixed using an extruder. Subsequently, it was formed into a cord shape having a diameter of about 2 mm or more and 4 mm or less by an extrusion molding machine, and heat treated at 150 ° C. for 2 hours to obtain a silicone rubber magnet. Next, the rubber magnet was crushed in liquid nitrogen to obtain rubber magnet particles having an average particle diameter of 150 μm. A composite member was obtained in the same manner as in Example 1 except that the compound and the rubber particles were charged into the injection molding machine such that the mass ratio of the rubber magnet particles to 100 parts by mass of the compound was 5.0 parts by mass.

(Example 6)
A composite member was obtained in the same manner as in Example 5 except that rubber magnet particles having an average particle diameter of 300 μm were obtained.

(Example 7)
A composite member was obtained in the same manner as in Example 5 except that rubber magnet particles having an average particle diameter of 500 μm were obtained.

(Example 8)
A composite member was obtained in the same manner as in Example 5 except that rubber magnet particles having an average particle diameter of 1 mm were obtained.

(Comparative example 2)
Rubber magnet particles were obtained in the same manner as in Example 5. 91% by mass of Sm-Fe-N magnetic material surface-treated in the same manner as in Example 1 and 9% by mass of polyamide 12 The amount of rubber magnet particles having an average particle diameter of 150 μm obtained in Example 5 and The same amount was mixed by a mixer, and a compound was obtained in the same manner as Example 1 except that the obtained mixed powder was kneaded at 240 ° C. using a twin-screw kneader. The obtained compound was used for injection molding in the same manner as in Example 1 to obtain a composite member.

The thermal shock resistance and the magnetic flux density Br of Examples 5 to 8 and Comparative Example 2 were measured in the same manner as described above, and the results are shown in Table 2.

From Table 2, compared with Comparative Example 1 of Table 1, Examples 5 to 8 confirmed that the thermal shock resistance is improved while maintaining the magnetic flux density Br by including the rubber magnet particles. Moreover, when Example 5 and the comparative example 2 which used the same rubber magnet were compared, Example 5 confirmed that a thermal shock property improves. In Comparative Example 2, when rubber magnet particles are added in advance, the measuring torque at the time of injection molding is increased, so it was necessary to increase the molding temperature. As a result, the thermoplastic resin is deteriorated due to the high temperature, which is considered to cause a decrease in thermal shock resistance. Further, the reason why the pressure at the time of injection molding is increased by about 20% is considered to be because the secondary vulcanization of the silicone rubber occurred when kneading the compound and the rubber magnet particles, and the hardness of the rubber increased.

(Example 9)
The Sm-Fe-N magnetic material was surface-treated with ethyl silicate and a silane coupling agent. 91% by mass of the surface-treated Sm-Fe-N magnetic material, 7% by mass of polyamide 12, and 2% by mass of polyamide elastomer are mixed by a mixer. The obtained mixed powder was kneaded at 220 ° C. using a twin-screw kneader, and after cooling, was cut into a suitable size to obtain a pellet-like compound. Injection molding was performed in the same manner as in Example 1 using the obtained rubber particles and the same rubber particles as in Example 1 to obtain a composite member.

(Example 10)
Injection molding was performed in the same manner as in Example 1 using the compound obtained in Example 9 and the same rubber particles as in Example 2 to obtain a composite member.

(Example 11)
Injection molding was performed in the same manner as in Example 1 using the compound obtained in Example 9 and the same rubber particles as in Example 3 to obtain a composite member.

(Comparative example 3)
The compound used in Example 9 was injection molded in the same manner as in Example 1 to obtain a composite member.

The thermal shock resistance and the magnetic flux density of Examples 9 to 11 and Comparative Example 3 were measured in the same manner as described above, and the results are shown in Table 3.

From Table 3, it was confirmed that Examples 9 to 11 improve the thermal shock resistance while suppressing the decrease in the magnetic flux density by containing the rubber particles, as compared with Comparative Example 3.

(Example 12)
Injection molding was performed in the same manner as in Example 1 using the compound used in Example 9 and the same rubber magnet particles as in Example 5 to obtain a composite member.

(Example 13)
Injection molding was performed in the same manner as in Example 1 using the compound used in Example 9 and the same rubber magnet particles as in Example 6 to obtain a composite member.

(Example 14)
Injection molding was performed in the same manner as in Example 1 using the compound used in Example 9 and the same rubber magnet particles as in Example 7 to obtain a composite member.

The thermal shock resistance and the magnetic flux density of Examples 12 to 14 were measured in the same manner as described above, and the results are shown in Table 4.

From Table 4, Examples 12-14 confirmed that a thermal shock property improves more, maintaining a magnetic flux density by including rubber magnet particle | grains.

The cross-sectional photograph by the optical microscope of the bonded magnet produced in Example 7 is shown in FIG. It was confirmed from FIG. 1 that the rubber magnet 6 was present as particles in the bonded magnet including the magnetic powder, the thermoplastic resin and the rubber magnet particles.

From these results, it was confirmed that the presence of the rubber particles in the bonded magnet can provide a composite member having an annular bonded magnet excellent in thermal shock resistance and a method for producing the same.

By using the composite member having the annular bonded magnet obtained according to the aspect of the present invention, it is possible to obtain a rotating device such as a motor excellent in thermal shock resistance. Therefore, the obtained rotating device can be suitably used as a driving source of a fuel pump in a car, a motorcycle, or the like.

1: Metal member 2: Bond magnet 3: Magnetic particle 4: Thermoplastic resin 5: Rubber 6: Rubber magnet particle

Claims (9)

A composite member comprising: a substantially cylindrical or substantially annular metal member; and an annular bonded magnet provided on an outer periphery of the metal member,
It said annular bonded magnet, the thermoplastic resin, magnetic particles and rubber particles observed including,
The composite member, wherein the rubber particles do not contain a magnetic material, and the content in the annular bonded magnet is 0.3% by mass or more and 1.0% by mass or less . A composite member comprising: a substantially cylindrical or substantially annular metal member; and an annular bonded magnet provided on an outer periphery of the metal member,
The annular bonded magnet comprises a thermoplastic resin, magnetic particles and rubber particles,
Double coupling member at least partially Ru Oh rubber magnet particles comprising magnetic particles of the rubber particles. The composite member according to claim 1, wherein the rubber particles include silicone rubber. The composite member according to any one of claims 1 to 3, wherein an average particle size of the rubber particles is more than 0.7 μm and less than 1 mm. A method of manufacturing a composite member including a substantially cylindrical or annular metal member and an annular bonded magnet provided on the outer periphery of the metal member, the annular bonded magnet including a thermoplastic resin, magnetic particles, and rubber particles. And
Kneading the thermoplastic resin and the magnetic particles to obtain a compound;
The compound and the rubber particles, method for producing a multi coupling member you comprising a substantially cylindrical or substantially annular metallic member and the step of integrally molding. The method according to claim 5, wherein the addition amount of the rubber particles is 0.3 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the compound. The composite member according to claim 1, wherein an average particle diameter of the rubber particles not containing the magnetic material is 2 μm or more and 900 μm or less. The composite member according to claim 7, wherein an average particle diameter of the rubber particles not containing the magnetic material is 11 μm or more and 500 μm or less. The composite member according to any one of claims 2 to 4, wherein an average particle diameter of the rubber magnet particles is 50 μm or more and 900 μm or less.

Images