JPH0919093A - Permanent magnet of rotor - Google Patents

Abstract

PURPOSE: To enhance the centrifugal strength and flexural and torsional rigidity of a rotor by winding a monofilament on the surface of a magnet in a predeter mined direction in layers while always applying a constant tension and compounding with a matrix resin. CONSTITUTION: On the surface of a magnet 11, a monofilament 12 is wound up sequentially in layers in a predetermined direction always with a constant tension. By doing this winding, a comprsgsive stress is given to the main body of the magnet 11 and also flexural and torsional rigidity is given together. Here, to give a compressive stress in the radial direction is effective for reducing a tensile stress created in the radial direction which occurs within the magnet by the centrifugal force. Multiple layers of the monofilament wound up are thereafter compounded by a matrix resin and firmly fixed to prevent the monofilament wound up from being separated and loosened. In this way, the compressive stress is given to the main body of the magnet and also flexural and torsional rigidity is applied together so that the above will greatly contribute to the improvement of centrifugal strength and flexural and torsional rigidity for a rotor for the permanent magnet type rotary machine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet incorporated in a rotor such as a permanent magnet type high speed generator or an electric motor (capacity: about 20 to 300 kw).

[0002]

9 and 10 schematically show the structure of a rotor used in a conventional permanent magnet type high speed generator or electric motor (capacity: about 20 to 300 kw). In FIG. 9, reference numeral 01 is a shaft, 02 is a rare earth magnet, 03 is a non-magnetic metal cylinder, and 04.
Each show a non-magnetic disc. As shown in FIG. 9, in the conventional rotor, since the bending strength and rigidity of the rare earth magnet are low, a non-magnetic metal material thin cylinder such as austenitic stainless steel is used to restrain the magnet 02 inside from the outer peripheral portion, A method of increasing the strength and rigidity of the rotor is adopted.

FIG. 10 shows another rotor structure, in which the iron core groove 06 for restraining the magnet 02 formed in the iron core 05 has a wedge-shaped cross section so that when the centrifugal force acts, the iron core groove 06 is The magnet 02 is also constrained from both side surfaces.

[0004]

[Problems to be Solved by the Invention]

(1) By the advent of rare earth magnets represented by Nd-Fe-B system magnets, the magnetic characteristics of permanent magnets have been dramatically improved. In a permanent magnet type synchronous machine that incorporates such a strong magnet in the rotor, it is necessary to increase the energy density per unit volume and to increase the output by increasing the rotation speed, compared with induction machines and winding type synchronous machines. As a result, motors and generators can be made smaller, have higher performance, and have higher efficiency.

(2) On the other hand, the centrifugal force acting on the rotor further increases with the increase in speed and capacity of these rotary electric machines, but the rare earth magnet is essentially a brittle material, and its strength,
Mechanical properties such as rigidity and deformability are much lower than those of iron cores and other metallic materials that make up the rotor.

(3) For example, the bending strength of an Nd-Fe-B magnet is about 260 MPa (1/2 or less of steel), the elastic modulus is about 150 GPa (3/4 of steel), and the elongation at break is about 0.2.
% (1/10 of steel or less), which is extremely small, and almost only plastic deformation does not lead to elastic deformation. But,
Compressive strength is more than twice as large as bending and tensile strength.

(4) To reduce the size of a rotating machine having the same capacity, it is necessary to increase the rotor diameter or increase the rotational speed to increase the rotor peripheral speed. Unless improved, increasing centrifugal force (F) is difficult to cope with.

[0008]

[Equation 1] Centrifugal force F = mrω ² where m: mass r: radius ω: angular velocity

When the rotor diameter is increased, GD ² (moment of inertia) is increased even if the rotor weight is the same.

[0010]

[Number 2] ^{GD 2 = (D 2/2} ) W where D: rotor diameter W: rotor mass

(5) Further, when the rotary machine capacity is increased without changing the rotor diameter and the rotation speed, it is necessary to increase the axial length of the rotor. At that time, the bearing (that is, the axial load support) is required. As the distance between the points increases, the bending and torsional strength and bending and torsional rigidity of the rotor must be further increased.

(6) When the thickness of the nonmagnetic metal cylinder shown in FIGS. 9 and 10 described above in relation to (4) and (5) is increased, the strength and rigidity of the rotor are increased, but in this case ,
There is a problem that this method cannot be adopted because the gap between the stator and the rotor magnet also becomes large and the efficiency of the rotating machine is reduced.

In view of the above circumstances, the present invention improves centrifugal force strength and bending torsional rigidity of a rotor, alleviates local stress concentration when assembling a magnet into a rotor, and prevents cracking or chipping of the magnet. It is an object of the present invention to provide a permanent magnet incorporated in a rotor that can be manufactured.

[0014]

The structure of a permanent magnet for a rotor according to the present invention which achieves the above object is obtained by winding monofilaments on the surface of a magnet in a layered manner while always applying a constant tension in a predetermined direction. It is characterized in that it is compounded with a resin.

The permanent magnet of the rotor is characterized in that the single fiber is a resin-impregnated semi-cure fiber, which is formed by winding and heating and curing.

The permanent magnet of the rotor is characterized in that it is obtained by winding monofilaments, impregnating them with a resin in an autoclave, and heating and curing under pressure.

In the rotor permanent magnet, the monofilaments are carbon fibers, silicon carbide fibers, and tyranno fibers (SiTi).
C), either Kepler fiber or glass fiber.

In the permanent magnet of the rotor, the carbon fiber as the single fiber is a pitch type high elastic modulus carbon fiber.

The permanent magnet of the rotor is characterized in that the matrix resin is any one of an epoxy resin, a PEEK (polyether ether ketone) resin and a polyimide resin.

A preferred embodiment of the present invention will be described below.

[0021]

EXAMPLES FIGS. 1 to 3 show an example of winding a single fiber on the surface of a round bar magnet. As shown in these drawings, according to the present invention, high elastic modulus and high strength fibers (hereinafter referred to as “reinforcing fibers”) are formed in a predetermined direction on the surface of the magnet 11 in a layered manner with monofilaments under constant constant tension. The filament is wound by the "filament winding method". By this winding, a compressive stress is applied to the main body of the magnet 11 as well as bending and torsional rigidity. Here, the application of the compressive stress in the radial direction has an effect of reducing the tensile stress in the radial direction generated in the magnet by the centrifugal force. This is because compressive stress is applied as an initial value.

An example of winding by a specific filament winding method will be described below.

(1) Method for winding monofilament on the surface of a round bar magnet shown in FIG. 1 Step 1: When an axis L in the same direction as the axis is drawn on the surface of the magnet 11 in the direction orthogonal to the axial direction, The single fibers 12 are wound in layers in a direction in which the angle (α ₁ ) is 90 degrees (see FIG. 1A). By this step 1, compressive stress is applied. Step 2: The monofilaments 12 are wound in layers in a direction that intersects the axial direction and that has an angle (α ₂ ) with the axis L of 15 degrees on the surface of the magnet 11 in the lower left direction in the figure (see FIG. 1 (b )reference).
This step 2 imparts bending rigidity. Step 3: Similar to Step 2, the monofilament 12 is wound in layers downward in the drawing in the direction intersecting the axial direction and at the angle (α ₂ ) with the axis L of 15 degrees on the surface of the magnet 11. (See FIG. 1 (c)). This step 3 imparts bending rigidity. Step (final step) 4: Similar to step 1, when the axis L of the same direction as the axis is drawn on the surface of the magnet 11 in the direction orthogonal to the axial direction, the angle (α ₁ ) becomes 90 degrees. The monofilaments 12 are wound in layers in the direction (see FIG. 1 (d)). By this step 4, compressive stress is applied and the bending rigidity of the lower layer wound fiber is fixed. In this way,
Through steps 1 to 4, it was possible to improve the radial tensile strength and the axial bending rigidity of the magnet 11. It is necessary to perform at least one step of each step without fail, and to perform the above steps 2 and 3 in pairs. However, the order of steps 2 and 3 may be reversed.

Method for winding monofilament around the surface of a round bar magnet shown in FIG. 2 Step 1: When an axis L in the same direction as the axis is drawn on the surface of the magnet 11 in the direction orthogonal to the axial direction, the angle (α _The single fiber 12 is wound in layers in the direction in which ₁ ) becomes 90 degrees (see FIG. 2A). By this step 1, compressive stress is applied. Step 2: The monofilaments 12 are wound in layers in a direction that intersects the axial direction and that has an angle (α ₃ ) with the axis L of 45 degrees on the surface of the magnet 11 in the lower left direction in the figure (see FIG. )reference).
This step 2 imparts torsional rigidity. Step 3: Similar to Step 2, the monofilament 12 is wound in layers downward in the figure in a direction that intersects the axial direction and the angle (α ₃ ) with the axis L is 45 degrees on the surface of the magnet 11. (See FIG. 2 (c)). Torsional rigidity is imparted by this step 3. Step (final step) 4: Similar to step 1, when the axis L of the same direction as the axis is drawn on the surface of the magnet 11 in the direction orthogonal to the axial direction, the angle (α ₁ ) becomes 90 degrees. The monofilaments 12 are wound in layers in the direction (see FIG. 2D). By this step 4, a compressive stress is applied and the torsional rigidity of the lower layer winding fiber is fixed. In this way, in steps 1 to 4, it was possible to improve the tensile strength in the radial direction and the torsional rigidity in the axial direction with respect to the magnet 11.
In addition, each step must be performed at least one layer, and the above step 2
And step 3 must be performed in pairs. However, the order of steps 2 and 3 may be reversed. Improves radial tensile strength and axial torsional rigidity.

Method for winding single fiber around the surface of a round bar magnet shown in FIG. 3 This method is a combination of the above-described winding methods shown in FIGS. 1 and 2. Step 1: The monofilament 12 is wound in layers in a direction orthogonal to the axial direction in a direction in which the angle (α ₁ ) is 90 degrees when the axis L in the same direction as the axis is drawn on the surface of the magnet 11. (See FIG. 3A). By this step 1, compressive stress is applied. Step 2: The monofilament 12 is wound in layers in a direction that intersects the axial direction and that has an angle (α ₂ ) with the axis L of 15 degrees on the surface of the magnet 11 in the lower left direction in the figure (see FIG. )reference).
This step 2 imparts bending rigidity. Step 3: Similar to Step 2, the monofilament 12 is wound in layers downward in the drawing in the direction intersecting the axial direction and at the angle (α ₂ ) with the axis L of 15 degrees on the surface of the magnet 11. (See FIG. 3 (c)). This step 3 imparts bending rigidity. Step 4: The monofilaments 12 are wound in layers in a direction that intersects the axial direction, and the angle (α ₃ ) to the surface of the magnet 11 is 45 degrees on the surface of the magnet 11 in the downward left direction in the figure (see FIG. )reference).
Torsional rigidity is imparted by this step 4. Step 5: Similar to Step 4, the monofilaments 12 are wound in layers downward in the figure in a direction intersecting the axial direction and at an angle (α ₃ ) with the axis L of 45 degrees on the surface of the magnet 11. (See Fig. 3 (e)). Torsional rigidity is imparted by this step 5. Step (final step) 6: Similar to step 1, when the axis L of the same direction as the axis is drawn on the surface of the magnet 11 in the direction orthogonal to the axial direction, the angle (α ₁ ) becomes 90 degrees. The single fibers 12 are wound up in layers in the direction (see FIG. 3 (f)). By this step 6, a compressive stress is applied and the bending and torsional rigidity of the lower layer winding fiber is fixed. In this way, by steps 1 to 6, it was possible to improve the tensile strength in the radial direction and the bending and torsional rigidity in the axial direction for the magnet 11. In addition, be sure to perform each step at least one more,
The above steps 2 and 3 and steps 4 and 5 must be performed in pairs. However, the order of steps 2 and 3 and steps 4 and 5 may be reversed. Moreover, you may repeat process 1-process 5 by turns as needed.

By the above steps, the monofilaments are wound around the surface of the magnet in layers to be roughly classified as follows. (A) Compressive stress is imparted by winding a single fiber in a layer shape in a direction perpendicular to the axial direction (α ₁ ), that is, in the circumferential direction or the plate width direction. (B) Bending rigidity is imparted by winding monofilaments in layers in the direction of ± 15 ° (α ₂ ) with respect to the axial direction. (C) Torsional rigidity is imparted by winding the single fibers in layers in a direction of ± 45 ° (α ₃ ) with respect to the axial direction.

Here, the reinforcing fibers used as the monofilaments to be wound into the above layer in the present invention are, for example, carbon fibers (particularly,
Pitch-based high elastic modulus carbon fiber), silicon carbide fiber, tyranno fiber (SiTiC), Kepler fiber, glass fiber, alumina fiber, boron fiber, whisker and the like can be mentioned.

Next, FIG. 4 shows the shape of the magnet which is the object of such fiber reinforcement. In FIG. 4, (a) shows a solid round bar (circular and elliptical cross section), and (b) shows a hollow round bar (circular and elliptical cross section). Further, (c) shows a solid or hollow hexagonal rod having a polygonal cross section. Also,
(D) shows a rectangular cross-section rod (plate-like) and (e) shows a semi-cylindrical cross-section rod (plate-like), respectively. In addition, in the present invention, the shape of the magnet is not limited to the above-mentioned shape, and a magnet appropriately modified according to the purpose may be used.

The monofilament winding layer formed in multiple layers is then
By forming a composite with a matrix resin, the single fibers are firmly fixed so as not to be separated, and the fiber-reinforced composite material for magnet reinforcement according to the present invention is obtained. As a method for obtaining the above-mentioned fiber-reinforced composite material for magnet reinforcement by fixing with this matrix resin, examples thereof are shown in (1) and (2).

<Fixing method (1)> A resin is applied (impregnated) to the surface of the fiber surface-activated with a silane coupling agent, wound into a single fiber in a semi-cure state, and then heat-cured (if necessary, if pressure is applied. There is also). In the present invention, the above-mentioned "semi-cured state" refers to a state in which the viscosity of the resin is increased and the curing reaction is slightly advanced as compared with the conventional impregnation of single fibers. That is, a fiber is impregnated with a resin, and the resin is heated a little to be semi-cured. The semi-cured fiber is in a soft state, but when heat is further applied, the resin is fully cured, I try to make it hard.

<Fixing method (2)> A fiber whose surface has been activated by a silane coupling agent is wound into a single fiber, and thereafter, a resin is vacuum-impregnated in an autoclave and is cured by heating under pressure.
The silane coupling agent may be mixed with the impregnating resin. Here, as the matrix resin, it is usually preferable to use an epoxy resin. When strength and toughness are required more than the above epoxy resin, PEEK
It is preferable to use a (polyether ether ketone) resin. When heat resistance is required (Max. 150)
Up to 200 ° C.), it is preferable to use a polyimide resin as a structural member.

Next, application examples of the fiber-reinforced solid and hollow round bar magnets according to the present invention to a rotor of a rotating machine are shown in FIGS.
As shown in FIG. FIG. 5 shows the case of application to a solid round bar magnet, and FIG. 6 shows the case of application to a hollow round bar magnet. In these drawings, reference numeral 21 is a shaft, 22 is a rare earth magnet, 23 is a non-magnetic metal cylinder, 24 is a non-magnetic metal disc, 3
Reference numeral 1 denotes a fiber-reinforced composite material for magnet reinforcement. (A) When the axial length is larger than the diameter, it is necessary to focus on improving bending rigidity. (B) However, if a large torque fluctuation is expected during actual use, it is necessary to take into consideration the improvement in torsional rigidity. (C) When the axial length is shorter than the diameter, it is necessary to focus on improving the torsional rigidity. (D) Countermeasures against centrifugal force (improvement of tensile strength in the radial direction) by applying compressive stress must be emphasized in all cases, and are especially important when increasing the rotor diameter.

7 and 8 show examples of application of fiber-reinforced rectangular and semi-cylindrical bar magnets to a rotor of a rotary machine, respectively.
FIG. 7 shows a case where the present invention is applied to a rectangular bar magnet, and FIG. 6 shows a case where it is applied to a semi-cylindrical bar magnet. In these drawings, reference numeral 21 is a shaft, 22 is a rare earth magnet, 23 is a non-magnetic metal cylinder, 24 is a non-magnetic metal disc, 25 is an iron core,
Reference numeral 26 is a rectangular or chamfered iron core groove, and 31 is a fiber-reinforced composite material for magnet reinforcement. (A) In this case, giving the compressive stress and improving the bending rigidity are important, and the improvement in the torsional rigidity does not have to be considered so much. (B) Further, as the axial length and the plate width increase, the improvement of bending rigidity becomes more important.

[0034]

As described above, according to the present invention, the following effects can be obtained. (1) On the surface of the magnet, a high elastic modulus and high strength fiber is wound in a predetermined direction under a constant tension to give a compressive stress to the magnet body, as well as bending and torsional rigidity. Therefore, it contributes to improvement of centrifugal force strength and bending and torsional rigidity as a rotor of a permanent magnet type rotating machine. (2) The monofilament winding layer formed in multiple layers is then finished into a composite material of a resin matrix, whereby the monofilaments are firmly fixed so as not to be separated and the matrix resin also bears strength. (3) Capable of responding to an increase in shaft length, an increase in centrifugal force (rotation speed, rotor diameter), and an increase in torque, respectively, and can be applied to a fiber-reinforced solid or hollow round bar magnet for a rotating machine / rotor. (4) Capable of responding to increases in axial length and plate width, and centrifugal force (rotation speed, rotor diameter), and can be applied to rotary machines and rotors with fiber-reinforced rectangular and chamfered section magnets. (5) Compared to metallic materials (for example, non-magnetic austenitic stainless steel), the magnet body can be reinforced with a fiber-reinforced composite material (resin matrix) having a large specific strength.
The rotor weight can be made lighter than the conventional method in which the rotor is reinforced from the outer peripheral side with only the metal cylinder, and it contributes to the reduction of the centrifugal force and the moment of inertia of the rotor. (6) When the magnet is incorporated into the rotor, the magnet and the metal material (iron core or non-magnetic metal cylinder) do not come into direct contact with each other, so that the magnet is less susceptible to local stress concentration (stress relaxation at the composite material part). It is possible to prevent the magnet from cracking or chipping.

[Brief description of the drawings]

FIG. 1 shows a process drawing of winding a single fiber around the surface of a round bar magnet according to this example.

FIG. 2 shows a process drawing of winding a single fiber around the surface of a round bar magnet according to this example.

FIG. 3 shows a process drawing of winding a single fiber around the surface of a round bar magnet according to the present embodiment.

FIG. 4 shows shape diagrams of various magnets to be fiber-reinforced.

FIG. 5 shows an application diagram to a high speed generator / motor rotor according to the present embodiment.

FIG. 6 shows an application diagram to a high speed generator / motor rotor according to the present embodiment.

FIG. 7 shows an application diagram to a high speed generator / motor rotor according to the present embodiment.

FIG. 8 shows an application diagram to a high speed generator / motor rotor according to the present embodiment.

FIG. 9 shows a schematic view of a rotor structure.

FIG. 10 shows a schematic view of another rotor structure.

[Explanation of symbols]

 11 magnet 12 monofilament 21 shaft 22 rare earth magnet 23 non-magnetic metal cylinder 24 non-magnetic metal disk 25 iron core 26 rectangular or chamfered core groove 31 fiber-reinforced composite material for magnet reinforcement

[Procedure amendment]

[Submission date] November 6, 1995

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 4

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction contents]

[0002]

2. Description of the Related Art FIGS. 9 and 10 schematically show the structure of a rotor used in a conventional permanent magnet type high speed generator or electric motor (capacity: about 20 to 300 kw). In FIG. 9, reference numeral 01 is a shaft, 02 is a rare earth magnet, 03 is a non-magnetic metal cylinder, and 04.
Each show a non-magnetic disc. As shown in FIG. 9, in the conventional rotor, since the bending strength and rigidity of the rare earth magnet are low, a non-magnetic metal material thin cylinder such as austenitic stainless steel is used to restrain the magnet 02 inside from the outer peripheral portion, A method of increasing the strength and rigidity of the rotor is adopted.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

In the rotor permanent magnet, the monofilaments are carbon fibers, silicon carbide fibers, and tyranno fibers (SiTi).
C), characterized in that either Ke blanking color fibers or glass fibers.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0027

[Correction method] Change

[Correction contents]

Here, the reinforcing fibers used as the monofilaments to be wound into the above layer in the present invention are, for example, carbon fibers (particularly,
Pitch-based high modulus carbon fiber), silicon carbide fiber, Tyranno fiber (SiTiC), Quai blanking color fibers can include glass fibers, alumina fibers, boron fibers or the like.

Claims (6)

[Claims] 1. A permanent magnet for a rotor, characterized in that monofilaments are wound on a surface of a magnet in a layered manner while always applying a constant tension in a predetermined direction and compounded by a matrix resin. 2. The permanent magnet for a rotor according to claim 1, wherein the single fiber is a resin-impregnated semi-cure fiber, and is obtained by heating and hardening after winding. 3. The permanent magnet for a rotor according to claim 1, wherein the single fiber is wound up, and then impregnated with a resin in an autoclave and cured by heating under pressure. 4. The rotor permanent magnet according to claim 1, wherein the single fiber is any one of carbon fiber, silicon carbide fiber, Tyranno fiber (SiTiC), Kepler fiber, and glass fiber. permanent magnet. 5. The permanent magnet for a rotor according to claim 4, wherein the carbon fiber as the single fiber is a pitch-based high elastic modulus carbon fiber. 6. The permanent magnet for a rotor according to claim 1, wherein the matrix resin is an epoxy resin, a PEEK (polyether ether ketone) resin, or a polyimide resin.