Rotor sleeve, rotor of rotary electric machine, and method for manufacturing rotor of rotary electric machine

Abstract

To provide a sleeve for a rotor, a rotor of a rotary electric machine, a method of manufacturing the sleeve for the rotor, and a method of manufacturing the rotor of the rotary electric machine, which are hardly affected by an operation condition and an installation condition of the rotary electric machine and can stably rotate the rotor.SOLUTION: A rotor sleeve 1 is used for a rotor 10 of a rotary electric machine including a permanent magnet 2, a shaft 3 provided on an end side of the permanent magnet 2, and the rotor sleeve 1 in which the permanent magnet 2 and the shaft 3 are disposed, the rotor sleeve 1 including a first cylindrical portion 4 made of metal and having a cylindrical shape with a constant inner diameter and a constant outer diameter, the permanent magnet 2 being disposed in the first cylindrical portion 4, and a second cylindrical portion 5 made of fiber reinforced plastic and having a cylindrical shape with a constant inner diameter, the first cylindrical portion 4 being disposed in the second cylindrical portion 5. The thickness of the second cylindrical part 5 is larger than the thickness of the first cylindrical part 4 over the whole from one end to the other end in the length direction of the first cylindrical part 4 and the second cylindrical part 5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a rotor sleeve, a rotor for a rotating electric machine, a method for manufacturing a rotor sleeve, and a method for manufacturing a rotor for a rotating electric machine. [Background technology]

[0002] A rotating electric machine has a rotor around an axis, and the rotor has a rotating shaft and a permanent magnet. A cylindrical member (also called a sleeve) is installed on the outer periphery of the permanent magnet to prevent the permanent magnet from flying off during rotation of the rotor.

[0003] In the following Patent Document 1, a first cylindrical member and a second cylindrical member are provided around a magnetic body, which is a permanent magnet, and a shaft member, the first cylindrical member being made of, for example, stainless steel, and the second cylindrical member being made of, for example, a titanium alloy or a carbon fiber reinforced material. The second cylindrical member is overlapped on the radially outer side of the first cylindrical member, and the thickness of the second cylindrical member is thinner than the thickness of the cylindrical main body of the first cylindrical member.

[0004] Furthermore, in Patent Document 2 listed below, a rotor includes a permanent magnet, a metal protective sleeve, and a CFRP shrink ring. The permanent magnet is fitted onto the outer periphery of the rotating shaft and has a truncated conical cylindrical shape with tapered inner and outer peripheries over the entire axial length. The protective sleeve has a tapered inner periphery corresponding to the outer periphery of the permanent magnet, and a tapered or cylindrical outer periphery. The shrink ring has a protective sleeve attached to its inner periphery, and the shape of the inner periphery is tapered or cylindrical corresponding to the outer periphery of the protective sleeve. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-38525 [Patent Document 2] Patent No. 4172066 Summary of the Invention [Problem to be solved by the invention]

[0006] As in the above-mentioned Patent Documents 1 and 2, there is a technique of applying fiber reinforced plastic such as carbon fiber reinforced plastic to a rotor sleeve in order to reduce the weight and improve the strength of the rotor.

[0007] However, in Patent Document 1, the first cylindrical member has low strength, the second cylindrical member has high strength, and the first cylindrical member is thicker than the second cylindrical member. Therefore, under conditions where a rotating electric machine is used at ultra-high speeds for a long period of time accompanied by heat cycles, creep deformation occurs in the first cylindrical member of the rotor disclosed in Patent Document 1, and the tension force for holding the permanent magnets inside is reduced.

[0008] Furthermore, in the example of Patent Document 2 in which the CFRP shrink ring is tapered (Fig. 1), the strength of the thinner side (i.e., the larger diameter side of the rotating shaft) is low, so the compressive force of the shrink ring on the magnet is weak. Therefore, if the rotating electric machine is used at ultra-high speeds for a long period of time accompanied by heat cycles, there is a risk that the rotor will break starting from the thinner side of the shrink ring.

[0009] Furthermore, in the example of Patent Document 2 in which the shrink ring is cylindrical (FIG. 3), similar to the tapered example in FIG. 1, the inner circumferential surface of the metal protective sleeve, the inner and outer circumferential surfaces of the permanent magnet, and the outer circumferential surface of the rotating shaft are all tapered, and each part has a shape with a different diameter along its length. Therefore, each part has a different coefficient of linear expansion within it. Therefore, when a rotating electric machine is used at ultra-high speeds for a long period of time accompanied by heat cycles, misalignment is likely to occur at the mating parts between parts. For example, when a rotating electric machine rotates at high speeds due to temperature changes, the thick side of the part may not deform, while the thin side may expand in diameter.

[0010] Furthermore, tapered components such as those described in Patent Document 2 require tapering for production, which poses the problem of increased effort and cost. Not only does it require adjusting the taper angle of each component, but misalignment of the angles makes it difficult to properly assemble the components, resulting in an unbalanced assembled rotor. Therefore, the rotor described in Patent Document 2 is difficult to apply to rotating electrical machines with ultra-high speeds.

[0011] In rotating electrical machines that operate at ultra-high speeds while undergoing long-term heat cycles ranging from below room temperature to above room temperature, there is a high possibility of creep deformation, especially in sleeves that have dual components arranged in them. As a result, the tension on the magnets provided by the sleeve is lost, causing the problem of rotor rotational balance being lost.

[0012] The present invention has been made in consideration of the above circumstances, and aims to provide a rotor sleeve, a rotor for a rotating electric machine, a method for manufacturing a rotor sleeve, and a method for manufacturing a rotor for a rotating electric machine, which are less susceptible to the operating conditions and installation conditions of a rotating electric machine and are capable of stably rotating the rotor. [Means for solving the problem]

[0013] In order to solve the above problems, the rotor sleeve, the rotor for a rotating electrical machine, the method for manufacturing a rotor sleeve, and the method for manufacturing a rotor for a rotating electrical machine of the present invention employ the following means. In other words, the rotor sleeve of the present invention is a rotor sleeve used in a rotor of a rotating electric machine having a permanent magnet, a shaft provided on the end side of the permanent magnet, and a rotor sleeve in which the permanent magnet and the shaft are arranged, and is characterized in that it comprises: a first cylindrical portion made of metal, which has a cylindrical shape with constant inner and outer diameters, and in which the permanent magnet is arranged so that the outer surface of the permanent magnet contacts its inner surface; and a second cylindrical portion made of fiber-reinforced plastic, which has a cylindrical shape with a constant inner diameter, and in which the first cylindrical portion is arranged so that the outer surface of the first cylindrical portion contacts its inner surface, and the thickness of the second cylindrical portion is greater than the thickness of the first cylindrical portion over the entire length of the first cylindrical portion and the second cylindrical portion from one end to the other.

[0014] In the above invention, the axial length of the first cylindrical portion and the second cylindrical portion may be longer than the axial length of the permanent magnet.

[0015] The rotor of a rotating electric machine according to the present invention comprises the above-mentioned rotor sleeve, a permanent magnet arranged inside the first cylindrical portion of the rotor sleeve, and a shaft arranged inside the first cylindrical portion of the rotor sleeve and provided on the end side of the permanent magnet.

[0016] The method for manufacturing a rotor sleeve according to the present invention is a method for manufacturing a rotor sleeve used in a rotor of a rotating electric machine having a permanent magnet, a shaft provided on the end side of the permanent magnet, and a rotor sleeve in which the permanent magnet and the shaft are arranged, and is characterized in that it includes a first press-fitting step in which a cylindrical first cylindrical portion made of metal is pressed into the inside of a cylindrical second cylindrical portion made of fiber-reinforced plastic, the thickness of the second cylindrical portion being greater than the thickness of the first cylindrical portion, and before the first press-fitting step, the outer diameter of the first cylindrical portion being greater than the inner diameter of the second cylindrical portion, and the first press-fitting step positions the first cylindrical portion inside the second cylindrical portion so that the outer surface of the first cylindrical portion is in contact with the inner surface of the second cylindrical portion.

[0017] A method for manufacturing a rotor for a rotating electric machine according to the present invention is a method for manufacturing a rotor for a rotating electric machine having a permanent magnet, a shaft provided on an end side of the permanent magnet, and a rotor sleeve in which the permanent magnet and the shaft are placed, and includes a first press-fitting step of press-fitting a cylindrical first cylindrical portion made of metal into a cylindrical second cylindrical portion made of fiber-reinforced plastic, and a second press-fitting step of press-fitting the cylindrical permanent magnet into the first cylindrical portion while the cylindrical permanent magnet is placed inside the second cylindrical portion, and the thickness of the second cylindrical portion is greater than the thickness of the first cylindrical portion. the outer diameter of the first cylindrical portion is larger than the inner diameter of the second cylindrical portion before the first press-fitting step, and the first cylindrical portion is disposed inside the second cylindrical portion by the first press-fitting step so that the outer surface of the first cylindrical portion contacts the inner surface of the second cylindrical portion; the outer diameter of the permanent magnet is larger than the inner diameter of the first cylindrical portion when disposed inside the second cylindrical portion before the second press-fitting step, and the permanent magnet is disposed inside the first cylindrical portion by the second press-fitting step so that the outer surface of the permanent magnet contacts the inner surface of the first cylindrical portion.

[0018] In the above invention, the ratio (δ2 / δ1) of the second interference (δ2), which is the difference between the outer diameter of the first cylindrical portion and the inner diameter of the second cylindrical portion before the first press-fitting step, to the first interference (δ1), which is the difference between the outer diameter of the permanent magnet before the second press-fitting step and the inner diameter of the first cylindrical portion when placed inside the second cylindrical portion, may be 0.8 or more and 1.6 or less.

[0019] In the above invention, the first interference (δ1) and the second interference (δ2) may have the same value. [Effects of the Invention]

[0020] According to the present invention, the rotor can be rotated stably without being affected by the operating conditions and installation conditions of the rotating electrical machine. [Brief explanation of the drawings]

[0021] [Figure 1]1 is a longitudinal cross-sectional view showing a rotor according to an embodiment of the present invention; [Figure 2] 1 is a flowchart illustrating a method for manufacturing a rotor according to an embodiment of the present invention. [Figure 3] 2A to 2C are schematic diagrams illustrating steps in a method for manufacturing a rotor according to an embodiment of the present invention. [Figure 4] 10 is a graph showing the relationship between the rate of change in the inner diameter of the first cylindrical portion and interference δ2 / interference δ1. DETAILED DESCRIPTION OF THE INVENTION

[0022] 1, a rotor 10 of a rotating electric machine according to one embodiment of the present invention includes a rotor sleeve (hereinafter referred to as "sleeve") 1, a permanent magnet 2, and a shaft 3 provided on the end side of the permanent magnet 2. The rotor 10 is a component installed in a rotating electric machine, and is installed together with a stator inside a housing of the rotating electric machine.

[0023] The permanent magnet 2 is cylindrical and is arranged inside the sleeve 1 so that its outer circumferential surface is in contact with the inner circumferential surface of the sleeve 1. The permanent magnet 2 and the sleeve 1 are arranged coaxially. The length of the permanent magnet 2 is shorter than the length of the sleeve 1, and the permanent magnet 2 is arranged approximately in the center of the sleeve 1, with the ends of the permanent magnet 2 located inside the sleeve 1.

[0024] The shaft 3 is cylindrical and is disposed inside the sleeve 1 so that its outer circumferential surface contacts the inner circumferential surface of the sleeve 1. The shaft 3 is disposed coaxially with the permanent magnet 2 and the sleeve 1. The rotor 10 is provided with two shafts 3, each disposed at either end of the permanent magnet 2, with the ends of the shafts 3 and the permanent magnet 2 contacting each other inside the sleeve 1.

[0025] The sleeve 1 includes a first cylindrical portion 4 made of metal and a second cylindrical portion 5 made of fiber-reinforced plastic, with the first cylindrical portion 4 disposed inside the second cylindrical portion 5. The axial lengths of the first cylindrical portion 4 and the second cylindrical portion 5 are longer than the axial length of the permanent magnet 2.

[0026] The first cylindrical portion 4 is made of a metal such as stainless steel, and has a cylindrical shape with constant inner and outer diameters. This allows for uniform tension along the length, unlike when a metallic cylindrical member has a tapered shape. The permanent magnet 2 is placed inside the first cylindrical portion 4 so that the outer surface of the permanent magnet 2 contacts the inner surface.

[0027] The second cylindrical portion 5 is made of fiber-reinforced plastic, such as CFRP (carbon fiber reinforced plastic), and has a cylindrical shape with constant inner and outer diameters. This allows for uniform tensioning force along the length, unlike when a cylindrical member made of fiber-reinforced plastic has a tapered shape. The first cylindrical portion 4 is disposed inside the second cylindrical portion 5 so that the outer surface of the first cylindrical portion 4 contacts the inner surface of the second cylindrical portion 5.

[0028] The thickness of the second cylindrical portion 5 is greater than the thickness of the first cylindrical portion 4 across the entire length of the first cylindrical portion 4 and the second cylindrical portion 5, from one end to the other. This allows the tensioning force of the fiber-reinforced plastic second cylindrical portion 5 to reliably fix the first cylindrical portion 4 to the interior. Unlike this embodiment, if the fiber-reinforced plastic cylindrical portion located on the outside is thinner than the metal cylindrical portion located on the inside, the tensioning force is weaker, and creep deformation is likely to occur under conditions such as when the rotating electrical machine is used at ultra-high speeds for long periods of time accompanied by heat cycles. In contrast, this embodiment can suppress creep deformation even under such conditions.

[0029] Next, a method for manufacturing the rotor sleeve 1 and a method for manufacturing the rotor 10 will be described with reference to FIGS. First, to manufacture the sleeve 1, the first cylindrical portion 4 made of metal and the second cylindrical portion 5 made of fiber-reinforced plastic are separately manufactured (step S11).

[0030] 3(A), the cylindrical first cylindrical portion 4 made of metal is press-fitted into the cylindrical second cylindrical portion 5 made of fiber-reinforced plastic (first press-fitting step) (step S12). Specifically, a lubricant such as molybdenum disulfide lubricant is applied to the surface of the first cylindrical portion 4, and the first cylindrical portion 4 is press-fitted into the second cylindrical portion 5 by a press.

[0031] Before the first press-fitting step, the outer diameter of the first cylindrical portion 4 located on the inside is larger than the inner diameter of the second cylindrical portion 5 located on the outside. In other words, the first cylindrical portion 4 and the second cylindrical portion 5 are manufactured so as to have an interference δ2 (second interference), which is the difference between the outer diameter of the first cylindrical portion 4 and the inner diameter of the second cylindrical portion 5 before the first press-fitting step.

[0032] By the first press-fitting step, the first cylindrical portion 4 is arranged inside the second cylindrical portion 5 so that the outer surface of the first cylindrical portion 4 contacts the inner surface of the second cylindrical portion 5. The interference δ2 (second interference) is set to a value that allows the first cylindrical portion 4 made of metal to be appropriately press-fitted inside the second cylindrical portion 5 made of fiber-reinforced plastic. In this way, the sleeve 1 according to this embodiment is manufactured.

[0033] 3(B), the cylindrical permanent magnet 2 is press-fitted into the sleeve 1 manufactured above, i.e., the first cylindrical portion 4 disposed inside the second cylindrical portion 5 (second press-fitting step) (step S13). Specifically, a lubricant such as molybdenum disulfide lubricant is applied to the surface of the permanent magnet 2, and the permanent magnet 2 is press-fitted into the first cylindrical portion 4 of the sleeve 1 by a press.

[0034] Before the second press-fitting step, the outer diameter of the permanent magnet 2 placed inside is larger than the inner diameter of the first cylindrical portion 4 when it is placed inside the second cylindrical portion 5. In other words, the permanent magnet 2, the first cylindrical portion 4, and the second cylindrical portion 5 are manufactured so as to have an interference δ1 (first interference), which is the difference between the outer diameter of the permanent magnet 2 before the second press-fitting step and the inner diameter of the first cylindrical portion 4 when it is placed inside the second cylindrical portion 5.

[0035] By the second press-fitting step, the permanent magnet 2 is arranged inside the first cylindrical portion 4 so that the outer surface of the permanent magnet 2 contacts the inner surface of the first cylindrical portion 4. The interference δ1 (first interference) may be a value that is generally used when press-fitting a permanent magnet into a sleeve.

[0036] 3(C), the cylindrical shaft 3 is press-fitted into the first cylindrical portion 4 of the sleeve 1 with the permanent magnet 2 disposed inside the first cylindrical portion 4 (step S14). The shaft 3 is press-fitted onto each of the ends on both sides of the permanent magnet 2. In this way, the rotor 10 according to this embodiment is manufactured.

[0037] Next, the interference set for each member for the above-mentioned press-fitting will be described. The ratio (δ2 / δ1) of interference δ2, which is the difference between the outer diameter of the first cylindrical portion 4 and the inner diameter of the second cylindrical portion 5 before the first press-fitting step, to interference δ1, which is the difference between the outer diameter of the permanent magnet 2 before the second press-fitting step and the inner diameter of the first cylindrical portion 4 when placed inside the second cylindrical portion 5, is preferably 0.8 or more and 1.6 or less. In particular, it is even better if the values ​​of interference δ1 and interference δ2 are the same (δ2 / δ1 = 1.0). The reason for this is as follows.

[0038] After the sleeve 1 was manufactured and the rotor 10 was manufactured, a creep test was performed on the rotor 10. The creep test was performed at 150°C for 72 hours. Multiple values ​​were set for the wall thickness of the first cylindrical portion 4, and multiple values ​​were set for the interference δ1 and interference δ2, to manufacture multiple types of rotors 10, and a creep test was performed on each rotor 10. After that, the permanent magnet 2 was removed, and the inner diameter of the metallic first cylindrical portion 4 was measured. The amount of change in the inner diameter of the first cylindrical portion 4 before and after the creep test was calculated.

[0039] As a result, as shown in Figure 4, regardless of the wall thickness of the first cylindrical portion 4 or the absolute values ​​of the interference δ1 and interference δ2, when the ratio of interference δ2 to interference δ1 (δ2 / δ1) was between 0.8 and 1.6, the change in the inner diameter of the first cylindrical portion 4 before and after the creep test was relatively small. In particular, when the ratio of interference δ2 to interference δ1 (δ2 / δ1) was 1.0, the change in the inner diameter of the first cylindrical portion 4 before and after the creep test was smallest.

[0040] In other words, regardless of whether the creep test was performed or not, it can be said that the metallic first cylindrical portion 4 deformed within the elastic range without plastic deformation when the ratio of the interference δ2 to the interference δ1 (δ2 / δ1) was within the above-mentioned range. Therefore, even when the rotor 10 was used under severe conditions such as high temperatures, the tension force exerted by the sleeve 1 on the permanent magnet 2 could be maintained. On the other hand, when the ratio of the interference δ2 to the interference δ1 (δ2 / δ1) was less than 0.8 and more than 1.6, the change in the inner diameter of the first cylindrical portion 4 before and after the creep test was relatively large, which could result in a relatively low tension force exerted by the sleeve 1 on the permanent magnet 2. [Explanation of symbols]

[0041] 1: Rotor sleeve (sleeve) 2: Permanent magnet 3: Shaft 4: First cylindrical part 5: Second cylindrical part 10: Rotor

Claims

1. A rotor sleeve for use in a rotor of a rotating electric machine, the rotor sleeve having a permanent magnet, a shaft provided on an end side of the permanent magnet, and a rotor sleeve in which the permanent magnet and the shaft are disposed, a first cylindrical portion made of metal, having a cylindrical shape with a constant inner diameter and a constant outer diameter, and having the permanent magnet disposed therein so that the outer surface of the permanent magnet is in contact with the inner surface of the first cylindrical portion; a second cylindrical portion made of fiber reinforced plastic, having a cylindrical shape with a constant inner diameter, with the first cylindrical portion disposed therein so that the outer surface of the first cylindrical portion is in contact with the inner surface of the second cylindrical portion; Equipped with A rotor sleeve characterized in that the thickness of the second cylindrical portion is greater than the thickness of the first cylindrical portion throughout the entire length of the first cylindrical portion and the second cylindrical portion from one end to the other.

2. The rotor sleeve according to claim 1 , wherein the axial length of the first cylindrical portion and the second cylindrical portion is longer than the axial length of the permanent magnet.

3. The rotor sleeve according to claim 1 or 2; a permanent magnet disposed inside the first cylindrical portion of the rotor sleeve; a shaft disposed inside the first cylindrical portion of the rotor sleeve and provided on an end side of the permanent magnet; A rotor for a rotating electric machine comprising:

4. A method for manufacturing a rotor sleeve used in a rotor of a rotating electric machine having a permanent magnet, a shaft provided on an end side of the permanent magnet, and a rotor sleeve in which the permanent magnet and the shaft are disposed, comprising: a first press-fitting step of press-fitting a cylindrical first cylindrical portion made of metal into a cylindrical second cylindrical portion made of fiber-reinforced plastic; The thickness of the second cylindrical portion is greater than the thickness of the first cylindrical portion, Before the first press-fitting step, an outer diameter of the first cylindrical portion is larger than an inner diameter of the second cylindrical portion, A method for manufacturing a rotor sleeve, characterized in that the first cylindrical portion is positioned inside the second cylindrical portion by the first press-fitting process so that the outer surface of the first cylindrical portion contacts the inner surface of the second cylindrical portion.

5. A method for manufacturing a rotor for a rotating electric machine having a permanent magnet, a shaft provided on an end side of the permanent magnet, and a rotor sleeve in which the permanent magnet and the shaft are disposed, the method comprising: a first press-fitting step of press-fitting a cylindrical first cylindrical portion made of metal into a cylindrical second cylindrical portion made of fiber-reinforced plastic; a second press-fitting step of press-fitting a cylindrical permanent magnet into the first cylindrical portion while the permanent magnet is disposed inside the second cylindrical portion; Equipped with The thickness of the second cylindrical portion is greater than the thickness of the first cylindrical portion, Before the first press-fitting step, an outer diameter of the first cylindrical portion is larger than an inner diameter of the second cylindrical portion, the first cylindrical portion is disposed inside the second cylindrical portion such that the outer surface of the first cylindrical portion is in contact with the inner surface of the second cylindrical portion by the first press-fitting step; Before the second press-fitting step, an outer diameter of the permanent magnet is larger than an inner diameter of the first cylindrical portion when the permanent magnet is disposed inside the second cylindrical portion, A method for manufacturing a rotor for a rotating electric machine, characterized in that the permanent magnet is positioned inside the first cylindrical portion by the second press-fitting process so that the outer surface of the permanent magnet is in contact with the inner surface of the first cylindrical portion.

6. 6. A method for manufacturing a rotor for a rotating electric machine as described in claim 5, wherein a ratio (δ2 / δ1) of a second interference (δ2) which is the difference between the outer diameter of the first cylindrical portion and the inner diameter of the second cylindrical portion before the first press-fitting process to a first interference (δ1) which is the difference between the outer diameter of the permanent magnet before the second press-fitting process and the inner diameter of the first cylindrical portion when disposed inside the second cylindrical portion is 0.8 or more and 1.6 or less.

7. 7. The method for manufacturing a rotor for a rotating electrical machine according to claim 6, wherein the first interference (δ1) and the second interference (δ2) have the same value.

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