JP2024043206A - Bonded magnet with case - Google Patents

Abstract

To provide a bonded magnet with a case capable of ensuring rust resistance of a bonded magnet and the adhesion between the bonded magnet and the case.SOLUTION: The bonded magnet with a case includes: a bond magnet containing rare earth magnet powder and a thermosetting resin; a case in which the bond magnet is inserted; and a sealing material. The sealing material is fixed in a bond magnet insertion opening of the case, and the bond magnet is sealed with the sealing material and the case. The sealing material consists of a compound with siloxane bonds.SELECTED DRAWING: Figure 1

Description

The present invention relates to a cased bonded magnet, and in particular to a cased bonded magnet used in a sensor that detects angles without contact.

Bonded magnets, which are formed by bonding magnet powder such as rare earth alloys with a resin binder, have inferior magnetic properties than binder-less sintered magnets due to the resin binder, but they can be easily processed into any shape and their dimensions are Due to its excellent accuracy, it is used for various purposes. Note that the resin binder is generally selected from epoxy resin, polyamide resin, phenol resin, and PPS resin in many cases.

For example, in the automotive field, sensor applications that detect angles without contact include cooling water and gas flow path switching valves to efficiently cool engines, inverters, batteries, etc. of HEVs and EVs, and other oil and gas flow path switching valves. It is used as a sensor magnet to detect the opening/closing degree of valves and valve bodies in pumps, fuel pumps, etc.In the industrial machinery field, sensor magnets are used to detect the angle and rotation speed of robot joints, motors, gears, etc. ), etc.

When rare earth magnet powder is used in a bonded magnet, there is a risk of deterioration of magnetic properties due to rust or oxidative corrosion, especially since compressed bonded magnets have a large surface area because they are porous, and contain iron and rare earths that are prone to rust. This is particularly noticeable in high-temperature, high-humidity environments and corrosive environments that come into contact with fluids such as water. Therefore, the above-mentioned problem is solved by forming, for example, a resin coating film by electrodeposition coating, electrostatic coating, spray coating, etc., or a plating film such as nickel plating on the magnet surface.

Patent Document 1 proposes a method for manufacturing a bonded magnet in which a rust-preventing thermosetting film is formed on the surface of a rare earth magnet by a dipping method. In this manufacturing method, dipping, drying, and curing are repeated 2 to 6 times to impregnate the voids inside the magnet with resin while forming a 0.005 mm to 0.05 mm rust-preventing thermosetting film on the magnet surface. .

In addition, in recent years, there has been a desire for higher performance magnetic properties, and in order to improve magnetic properties, the amount of magnetic powder blended is often increased and the amount of resin binder is reduced, making it difficult to ensure the strength of the magnet itself. There is. Therefore, in order to prevent direct damage to the magnet when using it, the magnet is generally protected by inserting it into a metal or resin case and fixing it with adhesive, or by insert molding. There are many.

Patent Document 2 discloses that after inserting a compacted powder of a rare earth bonded magnet into a case and sealing the insertion opening with a thermosetting resin, the resin binder of the bonded magnet and the thermosetting resin for sealing are cured. A method has been proposed in which the magnet surface is protected with a thermosetting resin while the magnet is fixed to the case.

JP2002-260943A Patent No. 6258689

In the method shown in Patent Document 1, it is necessary to additionally perform a process of forming a rust-preventive coating after forming the rare earth bonded magnet, and this process requires a lot of man-hours. In addition, there are electrodeposition coatings, electrostatic coatings, spray coatings, etc. other than the method shown in Patent Document 1, but all of them still require additional man-hours.

The method shown in Patent Document 2 achieves a reduction in the number of man-hours by performing such a process for preventing rust of the magnet at the same time as a process for fixing the magnet to the case. However, if the wettability of the rare earth bonded magnet and the thermosetting resin for sealing is poor or the viscosity of the resin is high, a portion of the magnet surface may be exposed after the curing process. Furthermore, the thermosetting resin for sealing is cured without contacting the case, and there is a concern that the magnet and the case may not be sufficiently fixed or rust prevention may be insufficient.

In view of the above-mentioned problems, the present invention provides a bonded magnet with a case that ensures the rust prevention of the bonded magnet and the adhesion between the bonded magnet and the case.

The bonded magnet with a case of the present invention is a bonded magnet with a case comprising a bonded magnet containing rare earth magnet powder and a thermosetting resin, a case into which the bonded magnet is inserted, and a sealing material, the bonded magnet with a case comprising: The sealing material is fixed to the insertion opening of the bonded magnet of the case, the bonded magnet is sealed with the sealing material and the case, and the sealing material is made of a compound having a siloxane bond. be.

According to the bonded magnet with a case of the present invention, the sealing material is fixed to the insertion opening, and the bonded magnet is sealed with the sealing material and the case, so that the sealing material is attached to the surface of the bonded magnet. And it can be filled into the gap between the bonded magnet and the case.

By the way, it is preferable to select a material that has good wettability to both the bonded magnet and the case as the sealing material. Wettability indicates the affinity (ease of adhesion) of a liquid to a solid surface. For this reason, sealing materials that have siloxane bonds in their molecules or that form siloxane bonds through hydrolysis reactions can be used. In particular, inorganic sealing materials made of alkoxysilane compounds with low viscosity, silane coupling agents, or similar compounds are preferable because they easily penetrate into the gap between the bonded magnet and the case. Here, siloxane is a general term for compounds with a skeleton of silicon and oxygen and that have Si-O-Si bonds (siloxane bonds). Siloxane is a functional group that has a Si-O-Si bond. This functional group exists in organosilicon compounds, and siloxane compounds can be either linear or branched compounds.

Incidentally, a silanol group can be chemically bonded to a metal or an inorganic compound, and when heated, a silanol group undergoes a dehydration condensation reaction with the same silanol group to form a siloxane bond and harden. Typical examples of materials that meet these characteristics include various silane coupling agents, various silicone oligomers, various silicone oils, and various silicone resins. Furthermore, an inorganic encapsulant containing an alkoxysilane compound or a partially hydrolyzed condensate thereof is most preferred. The sealant may contain an inorganic additive for adjusting viscosity and a curing catalyst for adjusting curing speed. If it is a silane coupling agent, a silane coupling agent in which the alkoxysilyl group is an ethoxy group and has an epoxy group is most preferable. A methoxy group can also be selected as the alkoxysilyl group, but it produces methanol upon hydrolysis. Ethoxy groups produce ethanol, which has a lower environmental impact than methanol. Furthermore, epoxy groups are most preferable because of their good reactivity with the epoxy resin and phenol resin of the bonded magnet.

The sealing material may contain one or more structures selected from secondary amines, sulfide bonds, ether bonds, and oxazolidone rings.

The binder resin of the bonded magnet may be an epoxy resin, and the case may be made of a non-magnetic metal material.

A bonded magnet with a case is a bonded magnet with a case that includes a bonded magnet containing rare earth magnet powder and a resin binder, a case into which the bonded magnet is inserted, and a sealing material, and the bonded magnet before hardening. A sealant having a contact angle with the magnet of less than 50° is used. Here, the contact angle is the angle formed between the solid surface with which the liquid is in contact and the end point of the liquid. Therefore, by simply dropping such a sealant, the entire surface of the bonded magnet can be covered with the sealant, and furthermore, the sealant can be placed between the case and the bonded magnet (gap). flow (infiltrate)

As the sealant, an inorganic sealant containing an alkoxysilane compound or a partially hydrolyzed condensate thereof, an inorganic additive, a curing catalyst, or a hydrolyzable alkoxysilyl group, an amino group, a glycidyl group, or an epoxy group. A silane coupling agent having one or more functional groups selected from , mercapto group, and isocyanate group can be used.

Alkoxysilane compounds or silane coupling agents have reaction mechanisms such as hydrolysis reactions and condensation reactions, and also react with oxidized surfaces or hydroxyl groups of inorganic materials using a similar mechanism. After the alkoxy group is hydrolyzed by moisture to generate a silanol group, it migrates to the substrate surface via hydrogen bonds with the hydroxyl group on the surface of the inorganic material, and then undergoes a dehydration condensation reaction to form a strong covalent bond with the surface of the inorganic material. do. In parallel with this reaction, silanol groups condense with each other to produce siloxane oligomers. These reactions can be accelerated by the presence of heat or a catalyst, and can be accelerated by removing by-product water, alcohol, etc. from the system by heating, drying, etc. From the above, it can be seen that the optimal processing conditions vary depending on the type of inorganic material and the processing environment. In general, inorganic substances with highly polar surfaces are advantageous for the migration of silane coupling agent molecules to the surface, and the rate of hydrolysis of silane coupling agent molecules gathered on the surface affects the surface pH and the amount of adsorbed water. be done. In addition, since the organic functional groups of the silane coupling agent molecules are oriented to the outside of the powder particles, etc., the optimal solvent and blending ratio are selected by considering the balance between hydrophilicity and hydrophobicity of the silane coupling agent solution. There is a need to.

By using inorganic sealing materials or silane coupling agents that contain these alkoxysilane compounds, it is possible to achieve effective wettability for both the bonded magnet and the case.

In the bonded magnet with a case according to the present invention, the surface of the bonded magnet and the gap between the bonded magnet and the case can be filled with a sealing material. This ensures the rust prevention of the bonded magnet and the adhesion between the bonded magnet and the case.

The bonded magnet with a case according to the present invention uses a sealing material that has a contact angle with the bonded magnet of less than 50° before hardening. Therefore, for example, by dropping this sealing material, the entire surface of the bonded magnet can be covered, and a rust prevention function can be effectively added. In addition, the sealing material flows between the case and the bonded magnet (gap), so that the bonded magnet is bonded to the case, and a bonded magnet with a case can be obtained.

FIG. 2 is a simplified cross-sectional view of a first bonded magnet with a case according to the present invention. FIG. 3 is a simplified cross-sectional view of a second bonded magnet with a case according to the present invention. FIG. 2 is a simplified diagram showing a method for manufacturing a first bonded magnet with a case according to the present invention. FIG. 3 is a simplified diagram showing a method for manufacturing a second bonded magnet with a case according to the present invention. FIG. 2 is a simplified diagram showing a state in which a liquid is dropped onto a solid surface. An explanation of the contact angle is shown, in which (a) is a simplified diagram when the contact angle is large, and (b) is a simplified diagram when the contact angle is small. FIG. 2 is a simplified diagram showing a method of measuring contact angle. FIG. 2 is a simplified diagram showing a method for testing the adhesive strength of a bonded magnet with a case.

Embodiments of the present invention will be described below based on FIGS. 1 to 8.

FIG. 1 shows a first cased bonded magnet according to the present invention, and FIG. 2 shows a second cased bonded magnet according to the present invention. A bonded magnet with a case according to the present invention includes a bonded magnet 1 made of rare earth magnet powder and a thermosetting resin, a case 2 into which the bonded magnet 1 is inserted, and a sealing material 3. That is, the case 2 has an insertion opening 2a into which the bonded magnet 1 is inserted, a sealing material is fixed to the insertion opening 2a, and the bonded magnet 1 is sealed with the sealing material 3 and the case 2. has been done.

Rare earth bonded magnets are composed of magnetic powder and a resin binder. The magnetic powder can be any rare earth type, such as Nd-Fe-B, Sm-Fe-N, or Sm-Co. Thermosetting resins such as epoxy resin or phenol resin are selected as the resin binder. The case is preferably made of a non-magnetic material, as this does not adversely affect the magnetic properties. For this reason, there are combinations of rare earth bonded magnets with metal cases, and rare earth bonded magnets with resin cases.

The sealing material 3 is made of a material that has good wettability for both the rare earth bonded magnet and the case. Examples of such materials include compounds having an alkoxysilyl group and one or more functional groups selected from an amino group, a glycidyl group, an epoxy group, a mercapto group, and an isocyanate group. For example, compounds represented by chemical formulas 1, 2, 3, 4, and 5.

Alkoxysilyl groups are hydrolyzed to form silanol groups that can be chemically bonded to metals and inorganic compounds, while amino groups, glycidyl groups, epoxy groups, mercapto groups, isocyanate groups, etc. are chemically bonded to resins contained in bonded magnets. . The amino group forms a secondary amine, the glycidyl group, the epoxy group forms an ether bond, the mercapto group forms a sulfide bond, and the isocyanate group forms an oxazolidone ring and is cured. Moreover, the silanol group undergoes a dehydration condensation reaction with the same silanol group by heating to form a siloxane bond and harden. Typical examples of materials that meet these characteristics include materials that have siloxane bonds in their molecules or that form siloxane bonds through hydrolysis reactions, such as various silane coupling agents, various silicone oligomers, various silicone oils, and various silicone resins. Can be mentioned. In particular, an inorganic encapsulant or silane coupling agent made of an alkoxysilane compound having a low viscosity, or a compound similar thereto is preferred because it easily enters the gap between the bonded magnet and the case. A methoxy group can also be selected as the alkoxysilyl group, but it produces methanol upon hydrolysis. Ethoxy groups produce ethanol, which has a lower environmental impact than methanol. Furthermore, epoxy groups are most preferable because of their good reactivity with the epoxy resin and phenol resin of the bonded magnet.

Moreover, the sealing material 3 used in this bonded magnet with a case is cured by being treated at a predetermined temperature. The contact angle of the sealing material 3 before curing is selected to be less than 50°. By the way, when a liquid is dropped onto the surface of a solid body as shown in FIG. 5, the liquid becomes round due to its own surface tension, and the following equation 1 holds true. Here, γ _S is the surface tension of the solid, γ _L is the surface tension of the liquid, and γ _SL is the interfacial tension between the solid and the liquid.

This equation is called "Young's equation", and the angle between the tangent of the droplet and the solid is called the contact angle θ. As shown in FIG. 6(a), when the contact angle is large, it is difficult to get wet, and as shown in FIG. 6(c), when the contact angle is small, it is easy to get wet.

There is a θ/2 method for measuring the contact angle θ. As shown in FIG. 7, the contact angle θ can be determined by determining the radius r and height h of the droplet. That is, the equation shown in Equation 2 holds true, and since θ=2θ1, the equation shown in Equation 3 holds true. (The shape of a minute droplet can be assumed to be a part of a circle, and according to the naturalization theorem, θ=2θ1 holds true.) In this way, the θ/2 method uses the straight line connecting the left and right end points of the droplet and the apex to The contact angle θ is determined by determining the angle and doubling it.

Examples of the nonmagnetic material forming the case 2 include resin materials, rubber materials, stainless steel nonmagnetic materials such as austenitic materials, and the like. There are two types of stainless steel non-magnetic materials: sintered parts and machined parts. Sintered parts are advantageous in terms of heat resistance, dimensional accuracy, mass production, and cost, while machined parts are advantageous in terms of heat resistance, dimensional accuracy, and strength. It is advantageous. When using stainless steel cutting products, etc., in order to improve the adhesion with the sealing material made of thermosetting resin adhesive or resin injection molding, apply shot sand, etc. to the surface that will be in contact with the sealing material. Blast treatment, machining (surface roughening), and chemical treatment such as acid treatment may also be performed. Further, when a rubber material or a resin material is used, the degree of freedom in designing the shape is increased, and for example, a fitting structure that prevents the material from coming off after the resin hardens can be easily formed on the case side. Incidentally, cases made of non-magnetic materials such as stainless steel are generally expensive and have poor machinability, so the case part has a simple shape and the minimum size that can hold a compressed bond magnet, and this is used for general magnetic material shafts etc. It is preferable to connect it to the tip of the

Next, we will explain the manufacturing method of the cased bonded magnet according to the present invention. In this case, there is a method (first manufacturing method) in which the bonded magnet 1 is inserted into the case 2 and then the sealing material 3 is applied, and a method (second manufacturing method) in which the bonded magnet 1 coated with the sealing material 3 is inserted into the case 2. Figure 3 shows the first manufacturing method, and Figure 4 shows the second manufacturing method.

In the first manufacturing method shown in FIG. 3, as shown in FIG. 3(a), the bonded magnet 1 without the sealant 3 applied thereto is inserted into the case 2 through the insertion opening 2a thereof. In this state, a gap Sa is provided between the side surface (surrounding inner wall 4a) of the storage space 4 of the case 2 and the side surface (surrounding outer wall 1a) of the bonded magnet 1, and the height of the storage space 4 of the bonded magnet 1 is higher than that of the upper surface 1b. A gap Sb is provided between the upper surface 1b of the bonded magnet 1 and the opening end 4b of the storage space 4, which is higher than the opening end 4b of the cavity 4 (the opening end of the insertion opening 2a). In this case, the gap Sa is, for example, approximately 0.02 mm to 0.2 mm, and the gap Sb is, for example, approximately 0.1 mm to 0.5 mm. For example, the case 2 has a cylindrical shape with a bottom, the storage space 4 is also a circular hole, and the bonded magnet 1 has a cylindrical shape.

In this state, the sealing material 3 is dropped onto the upper surface 1b of the bonded magnet 1. In this case, as the sealing material 3 has a contact angle θ of less than 50° before curing and is easily wetted, it naturally spreads over the surface of the bonded magnet and the gap Sa , the sealing material will penetrate into the Sb. After that, the sealing material 3 is cured by processing at a predetermined temperature (for example, 80° C.). In this way, a bonded magnet with a case can be formed.

In the second manufacturing method shown in FIG. 4, first, as shown in FIG. 4(a), a sealant 3 (with a contact angle θ of 50 Drop the sealant). Next, as shown in FIG. 4(b), the bonded magnet 1 without the sealant 3 applied thereto is inserted into the case 2 through the insertion opening 2a. As a result, as shown in FIG. 4(c), the sealing material 3 penetrates into the gaps Sa and Sb. Thereafter, the sealing material 3 is cured by processing at a predetermined temperature (for example, 80° C.). In this way, a bonded magnet with a case can be formed. In this case as well, the case 2 has a cylindrical shape with a bottom, the storage space 4 also has a circular hole, and the bonded magnet 1 has a cylindrical shape.

In this way, regardless of the manufacturing method, an anti-rust coating is formed around the bonded magnet 1 using the sealing material 3. The sealing material 3 is hardened by treating it at a specified temperature (e.g., 80°C), and in this case, the atmosphere can be an oxidizing atmosphere such as air, an inert atmosphere such as nitrogen or argon, or even a vacuum.

In addition, if the rust prevention function is insufficient due to the above manufacturing method, a rust prevention coating may be additionally formed to form a plurality of layers. For example, there is a method in which a sealing material 3 is additionally applied to the anticorrosive coating formed by the above method to form a thick film. As for the type of sealing material 3, the above-mentioned inorganic sealing materials made of alkoxysilane compounds, various silane coupling agents, various silicone oligomers, various silicone oils, various silicone resins, etc. can be used, as well as those having good compatibility with the above-mentioned ones. Thermosetting resins can also be selected.

According to the bonded magnet with a case of the present invention, the sealing material 3 is fixed to the insertion opening 2a, and the bonded magnet 1 is sealed with the sealing material 3 and the case 2, so that the sealing material 3 is fixed to the insertion opening 2a. , the surface of the bonded magnet 1 and the gaps Sa and Sb between the bonded magnet 1 and the case 2 can be filled. Therefore, rust prevention of the bonded magnet 1 and adhesion between the bonded magnet 1 and the case 2 are ensured.

According to the method for manufacturing a bonded magnet with a case of the present invention, a sealant having a contact angle θ with the bonded magnet 1 before hardening of less than 50° is used. By doing so, the entire surface of the bonded magnet 1 can be covered, and a rust prevention function can be effectively added. In addition, the sealing material 3 flows between the case 2 and the bonded magnet 1 (gap), so that the case is bonded to the case, and a bonded magnet with a case can be obtained.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified in various ways. It can be used not only for spindle motors, such as magnetic rolls used in transfer, but also for vehicles, home appliances, office equipment, etc. The method for determining the contact angle θ of the sealing material 3 is not limited to the θ/2 method, but may be determined by other methods such as the tangent method or the curve fitting method.

<Evaluation of wettability>
The wettability of the sealing material 3 and the bonded magnet 1 was evaluated by the following test. Bonded magnet 1 was produced by compression molding a compound of Nd-Fe-B magnetic powder and bisphenol A type epoxy resin, and curing the epoxy resin under predetermined heat treatment conditions. Thereafter, 10 mg to 20 mg of the sealing material 3 was dropped onto the surface of the bonded magnet without performing a conventional anti-corrosion treatment, and when the flow of the droplet stopped, a photograph was taken from the side of the droplet with a digital camera. Thereafter, the ratio between the droplet radius r and the apex height h was calculated from the photograph, and the contact angle θ was determined by the θ/2 method. Table 1 shows the results. Example 1 for evaluating wettability has a smaller contact angle and better wettability than Comparative Examples 1 and 2 for evaluating wettability. In this case, as the sealant 3 of Example 1, an inorganic sealant made of an alkoxysilane compound (Permeate HS-200 (manufactured by D&D Co., Ltd.)) was used, and the sealant of Comparative Example 1 As the sealing material 3 of Comparative Example 2, liquid epoxy resin A (TB2230B (manufactured by Three Bond Co., Ltd.)) was used as liquid epoxy resin B (TB2225G (NEO) (manufactured by Three Bond Co., Ltd.)). Using.

<Adhesive strength evaluation>
First, a bonded magnet 1 produced by the method described in the evaluation of wettability and a case 2 of SUS304 produced by a powder metallurgy method were adhesively fixed. The bonded magnet 1 has a cylindrical shape and is not subjected to anti-rust treatment. The case 2 has an approximately cylindrical shape with an opening 2a at one end into which the magnet 1 is inserted. After preparing the bonded magnet 1 and the case 2, the bonded magnet 1 was inserted into the opening 2a of the case 2, and the sealing material 3 was applied dropwise from the upper surface thereof. Thereafter, the sealing material 3 was cured under predetermined heat treatment conditions, and the case 2 and the magnet 1 were fixed. That is, a bonded magnet with a case was formed using the first manufacturing method.

The adhesive strength was judged to pass or fail by the following test. First, a hole 2c (see Figure 8) was opened with a cutting tool such as a drill from the bottom surface 2b on the opposite side of the opening 2a of the case 2 of the cased bonded magnet to the interface between the case 2 and the magnet 1. Then, as shown in Figure 8, the cased bonded magnet 1 was placed on a ring-shaped base 5 with an inner diameter wider than the outer diameter of the magnet, a shaft 6 was inserted into the hole 2c, and a load equivalent to 60g was applied. If the magnet 1 did not separate from the case 2, it was judged to pass, and if the case 2 and magnet 1 separated, it was judged to fail. The results are shown in Table 2.

In Example 1 of adhesive strength evaluation, the sealing material 3 flowed into the gaps Sa and Sb between the bonded magnet 1 and the case 2, and the strength was at an acceptable level. In Comparative Examples 1 and 2 for adhesive strength evaluation, the droplets did not spread just by dropping the sealant, and the sealant 3 hardened without contacting the case 2, so the magnet 1 and case 2 were not fixed. First, magnet 1 fell. In this case, the sealant 3 of Example 1 also used an inorganic sealant made of an alkoxysilane compound (Permeate HS-200 (manufactured by D&D Co., Ltd.)), and the sealant 3 of Comparative Example 1 As the sealing material 3 of Comparative Example 2, one-component epoxy resin A (TB2230B (manufactured by Three Bond Co., Ltd.)) was used. )) was used.

<Rust prevention function evaluation>
Using the bonded magnet with a case produced in the adhesion evaluation described above, its antirust function was evaluated by a corrosion resistance test. The test conditions are shown below. The cased bonded magnet is placed in a constant temperature and humidity bath, heated to 85° C. and 85% Rh in 30 minutes, humidified, and held for a predetermined time (1000 hours). Thereafter, the temperature was lowered and dehumidified for 30 minutes, and the container was taken out. After the test was completed, the surface of the bonded magnet was checked using a microscope to determine the presence or absence of rust. Table 3 shows the results. In this case, since a bonded magnet with a case prepared for adhesion evaluation is used, the encapsulant 3 of Example 1 was also an inorganic encapsulant made of an alkoxysilane compound (Permeate HS-200 (D. Co., Ltd.)). As the sealing material 3 of Comparative Example 1, one-component epoxy resin A (TB2230B (manufactured by Three Bond Co., Ltd.)) was used, and as the sealing material 3 of Comparative Example 2, One-component epoxy resin B (TB2225G (NEO) (manufactured by ThreeBond Co., Ltd.)) was used.

In Example 1 of the rust prevention function evaluation, no rust was confirmed, and it was confirmed that the rust prevention function was satisfactory. Rust was confirmed in Comparative Example 1 and Comparative Example 2 for rust prevention function evaluation. In Comparative Examples 1 and 2 for rust prevention function evaluation, the droplets did not spread and did not flow into the gap between the case and the magnet, leaving a part of the magnet surface exposed.

1 Bonded magnet 2 Case 2a Insertion opening 2a Opening 3 Sealing material θ Contact angle

Claims (3)

A bonded magnet with a case comprising a bonded magnet containing rare earth magnet powder and a thermosetting resin, a case into which the bonded magnet is inserted, and a sealing material, the bonded magnet having an insertion opening in the case. The bonded magnet with a case is characterized in that the sealing material is fixed to the case, the bonded magnet is sealed with the sealing material and the case, and the sealing material is made of a compound having a siloxane bond. The bonded magnet with a case according to claim 1, wherein the sealing material contains one or more structures selected from a secondary amine, a sulfide bond, an ether bond, and an oxazolidone ring. The bonded magnet with a case according to claim 1 or 2, wherein the binder resin of the bonded magnet is an epoxy resin, and the case is made of a non-magnetic metal material.

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