JPH01321609A - Manufacturing method of magnetic gears - Google Patents

Abstract

PURPOSE:To make it excellent in magnetic characteristics, to increase mechanical strength, to enable strong joining with other member, and to reduce the cost by applying hot working and heat treatment after melting and casting R-TM-B alloy (rare earth transition metal boron line). CONSTITUTION:Alloy which has at least one kind of R among rare earth elements including Y, transition metals TM and boron B for its main ingredients is melted and casted, and then the cast ingot is hot-worked at the temperature of 500 deg.C or more. Also, after hot-working, it is heat-treated at the temperature of 250 deg.C or higher so as to manufacture a joined substance of a permanent magnet and a soft magnetic substance, and then after-processing such as cutting, etc., is applied so as to leave a part of the soft magnetic substance section as a structure part material or a magnetic circuit. That is, sufficient coercive force can be obtained simply by applying hot-working and heat treatment without going through processes of pulverizing and sintering cast ingot, and production process of the permanent magnet can be reduced sharply. Furthermore, it has magnetic characteristics of about seven times the conventional ferrite magnet and the intensity of the magnet itself is greater than the sintered product, and further solid phase junction between the magnet and other structure material or magnetic circuit is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a magnetic gear that can conduct rotation in a non-contact manner in industrial equipment and the like.

[Prior Art] Ferrite, alnico, rare earth sintered magnets, etc. have been used for magnetic gears in the past.

[Problems to be Solved by the Invention] However, conventional magnetic gears have the following problems.

When using ferrite magnets, the magnetic properties are far inferior to rare earth magnets, so the rigidity of the magnetic gear is reduced, and in order to compensate for this, a large magnetic circuit is constructed with a large magnet. It was necessary to focus the magnetic flux. Furthermore, since the magnet itself is brittle, there was a strength problem in that it could be damaged by centrifugal force.

When using alnico magnets, the magnet has extremely small coercive force, so it must be magnetized after it is installed in the device, and it must be structured so that no demagnetizing field is applied during use. There was a problem.

Rare earth sintered magnets have satisfactory magnetic properties, but their mechanical strength is inferior to that of ferrite magnets, causing problems such as damage due to centrifugal force, cracking and chipping due to shock and vibration, and the raw material cost is high, making it difficult to use magnets. The problem was that it was very expensive.

In addition, when manufacturing rare earth iron boron based sintered magnets with low raw material costs by the sintering method, a process of turning the alloy into powder is essential, but R-T M-B alloys are extremely sensitive to oxygen. It is active, so when it goes through the process of powdering, its surface area increases, oxidation becomes intense, and the oxygen temperature in the sintered body inevitably increases. Also, when molding the powder, molding aids such as zinc stearate must be used. Although this is removed before the sintering process, there is a problem in that it remains in the magnet in the form of carbon for several moments, degrading the magnetic performance of the R-T M-B magnet.

The molded body after press molding with the addition of a molding aid is called a green body. It is very fragile and difficult to handle. Therefore, another major drawback is that it takes a considerable amount of effort to arrange them neatly in a sintering furnace.

Furthermore, in order to obtain an anisotropic magnet, press molding must be performed in a magnetic field, which requires large equipment such as a magnetic field power source and a coil.

Because of the above drawbacks, generally speaking, R-TM-B
Manufacturing sintered magnets of this type not only requires expensive equipment, but also reduces production efficiency and increases the manufacturing cost of the magnets. Therefore, R-T M-, which uses relatively cheap raw materials,
It was not possible to take advantage of the advantages of B-series magnets.

Furthermore, all conventional magnets had the structure described in Utility Model Application Laid-open No. 53-150378 and shown in Figure 2, in which the magnet was manufactured as a single unit and then fixed to a yoke, structural member, etc. by gluing. There was also a serious problem in that the magnets could peel off from the yoke, structural members, etc. due to the centrifugal force that accompanies the high-speed rotation of the gears.

Therefore, the present invention is intended to solve such problems, and its purpose is to melt and cast R-TM-B alloy as a basic process, and to use hot working and heat treatment in combination to improve magnetic properties. Our goal is to provide low-cost magnetic gears that have excellent mechanical properties, high mechanical strength, and can be strongly bonded to other parts.

[Means for Solving the Problems] In order to solve the above problems, the method for manufacturing a magnetic gear of the present invention uses R (where R is at least one rare earth element including Y), a transition metal, and boron. After melting and casting the alloy as a basic component, the cast ingot is hot worked at a temperature of 500° C. or higher.

In addition, the magnetic alloy is melted and cast, the cast ingot is then covered with a soft magnetic material, hot worked at a temperature of 500°C or higher, and then heat treated at a temperature of 250°C or higher to form a joined body of the permanent magnet and the soft magnetic material. It is characterized in that it is manufactured and then subjected to post-processing such as cutting so that a part of the soft magnetic material portion of the joined body remains as a structural member or a magnetic circuit.

Alternatively, a process of melting the magnet alloy and casting it into a mold made of a soft magnetic material or a material used to bond with the magnet, hot working the cast ingot together with the mold at a temperature of 500°C or higher, and then heating it at a temperature of 250°C or higher. Heat treatment is performed to produce a joined body of the permanent magnet and the mold material, and further, one part of the mold material part of the joined body is
It is characterized by performing post-processing such as cutting so that the parts remain as structural members or magnetic circuits.

[Example 1] FIG. 1 shows a side view of a magnetic gear manufactured by the manufacturing method of the present invention. 1 is a permanent magnet whose main components are rare earths, transitional metals, and boron; 2 is an internal mold with holes drilled; and 3 is a magnetic gear shaft. Table 1 shows the composition of the magnet alloy of this example.

Table 1 However, the composition of the magnet is not limited to the composition shown in Table 1, and the rare earth metals include Y, La, Ce, Pr.
, Nd, Sm, Eu, Gd, Tb
, DV.

Ho, Er, Tm, Yb, Lu are listed as candidates,
One or a combination of two or more of these may be used. The highest magnetic properties are obtained with Pr. Practically, therefore, Pr, Pr-Nd, Ce-Pr-Nd alloys, etc. are used.

Transferable metals include Fe, Co, Ni, and Cu.
, etc. are listed as candidates, and one or a combination of two or more of these may be used. In addition, additive elements for small plates, such as heavy rare earths Dy, Tb, etc., A1, S
i, Mo, Ga, etc. are effective in improving coercive force.

The main phase of R-T M-B permanent magnet is R2T M + 4
This is the B compound phase. Therefore, if R is less than 8 at %, the above-mentioned compound is no longer formed and high magnetic performance cannot be obtained. On the other hand, when R exceeds 30 atomic %, the nonmagnetic R-rich phase increases and the magnetic properties deteriorate significantly.

Therefore, the appropriate range for R is 8 to 30 atomic %.

However, in order to form a cast magnet, it is preferably 8 to 25 atomic %.

B is an essential element for forming the R2TMIaB compound phase, and if it is less than 2 atomic %, it becomes a rhombohedral R-TM system, so a high coercive force cannot be expected. Moreover, if it exceeds 28 at %, the amount of non-magnetic phase containing B increases, and the residual magnetic flux density decreases significantly. However, for cast magnets, the B content is preferably 8 at% or less; if it exceeds this, it will not be possible to obtain a fine R2T M + a B compound phase unless special cooling is performed, and an appropriate coercive force will not be obtained. I can't get it.

A1, Ga, etc. exhibit the effect of increasing coercive force. Since A1 and Ga are non-magnetic elements, the residual magnetic flux density decreases as the amount of addition ■ increases, and when A1 exceeds 15 at% and Ga exceeds 6 at%, it becomes less than a hard ferrite. Since the residual magnetic flux density becomes , it cannot fulfill its purpose as a rare earth magnet. Therefore, the amount of A1 added is preferably 15 at % or less, and the amount of Ga is preferably 6 at % or less.

The alloy having the composition shown in Table 1 is melted and cast into iron inner molds 2 and outer molds 4 assembled by welding as shown in Fig. 3. After cooling, a lid 5 is welded to the top and heated to 950°C. , hot extrusion was performed. Then, heat treatment was performed to obtain a solid-phase joined body of the permanent magnet 1, the inner mold 2, the outer mold 4, and the lid 5 shown in FIG. The magnetic properties of this permanent magnet 1 are shown in Table 2.

The assembled body shown in Table 2 and Figure 2 is made by cutting the mold M5, drilling a hole in the inner mold 2, cutting the outer mold 4, slicing it to the desired thickness, press-fitting the magnetic gear shaft 3, and forming the first A magnetic gear as shown in the figure was manufactured.

Furthermore, the present invention can also be applied to magnetic coupling by configuring it as an internal gear with a reduction ratio of 1:1 as shown in FIG. The driving side consists of an internal mold 2 into which a magnetic coupling drive shaft 6 is press-fitted and a permanent magnet 1, and the driven side consists of a solid-state joint of a mold and a magnet manufactured by combining a mold with a diameter larger than that of the driving side. The mold part has been removed.

[Effects of the Invention] As described above, in the method for manufacturing a magnetic gear of the present invention, sufficient coercive force can be obtained by simply subjecting a cast ingot to hot working and heat treatment without going through the steps of crushing and sintering. , the production process of permanent magnets can be significantly reduced.

Furthermore, as a magnetic property, the maximum energy product of Example 1
Since it has magnetic properties of 16 to 17 (MGOe), about seven times that of conventional ferrite magnets, it is possible to construct small and highly rigid magnetic gears.

In addition, the strength of the magnet itself is much greater than that of fired crystals,
Furthermore, since solid phase bonding is performed between the magnet and other structural materials or magnetic circuits, it is possible to manufacture magnetic gears that can be used without problems such as breakage or peeling even in magnetic gears that rotate at high speeds.

Furthermore, the present invention can also be applied to magnetic gears, that is, magnetic couplings with a rotational speed ratio of 1:1.

[Brief explanation of the drawing]

Fig. 1 is a side view of a magnetic gear produced by the manufacturing method of the present invention, Fig. 2 is a side view of a conventional magnetic gear, and Fig. 3 is a vertical cross-sectional view of the mold and magnet before hot working by the production method of the present invention. 4 is a longitudinal sectional view of a magnet and mold assembly after hot working according to the manufacturing method of the present invention, and FIG. 5 is a side view of a magnetic coupling which is an application example of the present invention. 1...Permanent magnet 2...Inner mold 3...Magnetic gear shaft 4...Outer mold 5...Lid 6...Magnetic coupling drive shaft and above Applicant Seiko Epson Corporation Agent Patent attorney Kisanbe Suzuki and 1 other person Figure 1 Figure 2 Figure 3 Prisoner 4 mu

Claims (3)

[Claims] (1) A method for manufacturing a magnetic gear in which rotation is transmitted non-contact by the magnetic force of a permanent magnet, in which R (where R is at least one rare earth element including Y), a transition metal, and boron are used as basic components. A method of manufacturing a magnetic gear, comprising melting and casting an alloy, and then hot working the cast ingot at a temperature of 500° C. or higher. (2) Process of melting and casting the magnetic alloy, then covering the cast ingot with a soft magnetic material, performing hot working at a temperature of 500°C or higher, and then heat treatment at a temperature of 250°C or higher to join the permanent magnet and the soft magnetic material. Claim 1, characterized in that a body is manufactured and further post-processing such as cutting is performed so that a part of the soft magnetic material portion of the joined body remains as a structural member or a magnetic circuit.
A method for manufacturing a magnetic gear described in . (3) The process of melting the magnet alloy and casting it into a mold made of a soft magnetic material or a material used for bonding with the magnet. The method is characterized in that a bonded body of a permanent magnet and a mold material is produced by heat treatment at a high temperature, and further post-processing such as cutting is performed so that a part of the mold material portion of the bonded body remains as a structural member or a magnetic circuit. A method for manufacturing a magnetic gear according to claim 1.