Rotor manufacturing method

Abstract

The rotor is manufactured quickly while minimizing material waste. [Solution] The method for manufacturing the rotor 4 comprises the steps of forming a first portion 4A, which includes at least a part of the rotor cylindrical portion 23 of the rotor 4, by mechanical processing, and forming a second portion 4B, which includes the rotor blades 22, by laminating it onto the first portion 4A.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a rotor of a vacuum pump.

Background Art

[0002] Some vacuum pumps include a rotor that has rotor blades and a rotor cylindrical portion and is rotationally driven (see, for example, Patent Document 1). In this vacuum pump, the rotor is rotated to suck the inside of the device to be evacuated, and the sucked gas is discharged to the outside.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventionally, components of a rotor such as rotor blades have been manufactured by forming a metal block (for example, a forged material) through mechanical processing such as cutting (machining). In the manufacture of a rotor by mechanical processing, there are problems such as the generation of chips, and particularly, the processing time becomes long due to the complex shape of the portion where the rotor blades are provided.

[0005] In order to solve the problems in the manufacture of a rotor by such mechanical processing, it is conceivable to manufacture a rotor using a shaping method by laminating materials (for example, additive manufacturing). In the shaping method by laminating materials, an object with an arbitrary shape can be formed by sequentially laminating layers of materials. Even when the entire rotor is manufactured by the above shaping method, problems such as the manufacturing time of the rotor becoming long because the materials are laminated and the rotor is formed in order, and the manufacturing cost of the rotor becoming high because a large amount of materials to be laminated is required occur.

[0006] Therefore, the objective of the present invention is to manufacture a vacuum pump rotor in a short time while minimizing material waste. [Means for solving the problem]

[0007] A method for manufacturing a rotor according to one aspect of the present invention is a method for manufacturing a rotor having rotor blades and a rotor cylindrical portion. The method for manufacturing a rotor comprises the following steps. (a) A step of forming a first portion, including at least a part of the rotor cylindrical portion, by mechanical processing. (b) A step of forming a second portion, including rotor blades, by stacking it on the first portion. [Effects of the Invention]

[0008] In a method for manufacturing rotors used in vacuum pumps, a first portion of the rotor, including at least a part of the rotor cylinder, is formed by mechanical processing, and the remaining portion of the rotor, i.e., the second portion including the rotor blades, is formed by laminating it onto the first portion. The first portion, including at least a part of the rotor cylinder, has a simple shape and can be formed easily and quickly by mechanical processing. On the other hand, the second portion, including the rotor blades, has a complex shape but can be easily formed by laminating it onto the first portion. Forming the entire rotor by lamination takes a long time and requires a lot of material, but by laminating only the second portion, the processing time can be reduced. In addition, since a lot of material is not required, the manufacturing cost of the rotor can be reduced.

[0009] In this way, by separating the rotor manufacturing process into a part formed by mechanical processing (first part) and a part formed by lamination (second part), the rotor can be manufactured easily and quickly while reducing the amount of shavings compared to when the entire rotor is formed by mechanical processing. Furthermore, the rotor can be manufactured in a shorter time and at a lower cost compared to when the entire rotor is formed by lamination. [Brief explanation of the drawing]

[0010] [Figure 1]This is a cross-sectional view of a vacuum pump. [Figure 2] This is a diagram illustrating the components that make up the rotor. [Figure 3] This figure shows an example of an additive manufacturing apparatus. [Figure 4] This is a flowchart showing the manufacturing method of the rotor. [Figure 5A] This figure shows an example of the formation of the first part. [Figure 5B] This is a schematic diagram (part 1) illustrating the process by which the second part is formed by laminating the first material. [Figure 5C] This is a schematic diagram (part 2) illustrating the process by which the second part is formed by laminating the first material. [Figure 5D] This is a schematic diagram (part 3) illustrating the process by which the second part is formed by laminating the first material. [Figure 6] This figure shows another embodiment of the first part. [Modes for carrying out the invention]

[0011] The rotor used in the vacuum pump and the manufacturing method of the rotor will be described below. First, a vacuum pump equipped with a rotor will be described using Figure 1. Figure 1 is a cross-sectional view of the vacuum pump 1. The vacuum pump 1 includes a housing 2, a base 3, a rotor 4, and a stator 5.

[0012] The housing 2 includes a first end 11, a second end 12, and a first internal space S1. The first end 11 is provided with an intake port 13. The intake port 13 is connected to the interior of an exhaust device (not shown) in a gas-flowable manner. The first internal space S1 is in communication with the intake port 13. The second end 12 is located opposite the first end 11 in the axial direction of the rotor 4 (hereinafter simply referred to as "axial direction A1"). The second end 12 is connected to the base 3. The base 3 includes a base end 14. The base end 14 is connected to the second end 12 of the housing 2.

[0013] The rotor 4 is housed in the internal space of the housing 2. The rotor 4 is attached to one end of the shaft 21. The shaft 21 extends in the axial direction A1. The shaft 21 is rotatably housed in the base 3. That is, the rotor 4 rotates due to the rotation of the shaft 21. A thrust disc 21A is provided at the lower part of the shaft 21. Furthermore, a target 21B is screwed to the lower end of the shaft 21.

[0014] The rotor 4 includes multiple stages of rotor blades 22 and a rotor cylindrical section 23. Each of the multiple stages of rotor blades 22 is connected to the shaft 21 at an angle with respect to the axial direction A1. The multiple stages of rotor blades 22 are spaced apart from each other in the axial direction A1. Although not shown in the figure, each of the multiple stages of rotor blades 22 extends radially from the shaft 21. In the figure, only one of the multiple stages of rotor blades 22 is labeled, and the labels of the other rotor blades 22 are omitted. The rotor cylindrical section 23 is located below the multiple stages of rotor blades 22. The rotor cylindrical section 23 extends in the axial direction A1.

[0015] The stator 5 is located on the outer circumference of the rotor 4. The stator 5 includes multiple stages of stator blades 31 and a stator cylindrical section 32. Each of the multiple stages of stator blades 31 is inclined in the opposite direction to the inclination of the rotor blades 22 and connected to the inner surface of the housing 2. For example, if the rotor blades 22 are inclined from the intake side to the exhaust side, the stator blades 31 are inclined from the exhaust side to the intake side. On the other hand, if the rotor blades 22 are inclined from the exhaust side to the intake side, the stator blades 31 are inclined from the intake side to the exhaust side. The inclination direction of the rotor blades 22 and stator blades 31 can be appropriately determined by the rotation direction of the rotor 4, etc.

[0016] The plurality of stages of stator blades 31 are arranged at intervals in the axial direction A1. The plurality of stages of stator blades 31 are respectively arranged between the plurality of stages of rotor blades 22. Although not shown in the figure, the plurality of stages of stator blades 31 each extend radially about the shaft 21. In the drawing, only two of the plurality of stages of stator blades 31 are labeled, and the labels of the other stator blades 31 are omitted. The stator cylindrical portion 32 is fixed in a state of contacting the base 3. The stator cylindrical portion 32 is arranged facing the outer peripheral surface of the rotor cylindrical portion 23 with a slight gap in the radial direction of the rotor cylindrical portion 23. A spiral groove is provided on the inner peripheral surface of the stator cylindrical portion 32 facing the rotor cylindrical portion 23.

[0017] As shown in FIG. 1, an exhaust space S2 is formed further downstream of the end portions on the exhaust downstream side of the rotor cylindrical portion 23 and the stator cylindrical portion 32. The exhaust target gas exhausted from the exhaust target device is guided into the exhaust space S2. The exhaust space S2 communicates with the exhaust port 15. The exhaust port 15 is provided in the base 3. Another vacuum pump (not shown) is connected to the exhaust port 15. Note that the exhaust downstream side means the side closer to the exhaust space S2 in the axial direction A1. Also, the exhaust downstream direction means the direction toward the exhaust space S2.

[0018] The vacuum pump 1 includes bearings 41A, 41E, magnetic bearings 41B to 41D, and a motor 42. The bearings 41A, 41E are attached to positions where the shaft 21 of the base 3 is housed. The bearings 41A, 41E rotatably support the shaft 21. The bearings 41A, 41E are ball bearings. The magnetic bearings 41B to 41D are bearings that support the shaft 21 by magnetic force. Among these, the magnetic bearings 41B, 41C are radial magnetic bearings that support the shaft 21 in the radial direction, and the magnetic bearing 41D is a thrust magnetic bearing that supports the shaft 21 in the axial direction.

[0019] The motor 42 rotates the rotor 4 by rotating the shaft 21. The motor 42 includes a motor rotor 42A and a motor stator 42B. The motor rotor 42A is attached to the shaft 21. The motor stator 42B is attached to the base 3. The motor stator 42B is positioned opposite the motor rotor 42A.

[0020] In vacuum pump 1, multiple stages of rotor blades 22 and multiple stages of stator blades 31 constitute the turbomolecular pump section. The rotor cylindrical section 23 and the stator cylindrical section 32 constitute the screw-groove pump section. In vacuum pump 1, the rotor 4 is rotated by the motor 42, causing the gas to be exhausted to flow from inside the waste disposal device into the first internal space S1 through the intake port 13. The gas to be exhausted in the first internal space S1 passes through the turbomolecular pump section and the screw-groove pump section and is guided to the exhaust space S2. The gas to be exhausted in the exhaust space S2 is exhausted from the exhaust port 15. As a result, the inside of the waste disposal device attached to the intake port 13 becomes a high vacuum state.

[0021] The rotor 4 will now be described in detail. As shown in Figure 2, the rotor 4 has a first part 4A and a second part 4B. Figure 2 is a diagram illustrating the parts that make up the rotor 4. In this embodiment, the first part 4A is the part from the lower end of the rotor cylindrical part 23 to the connection point between the rotor cylindrical part 23 and the lowest rotor blade 22. That is, the first part 4A is the part corresponding to the rotor cylindrical part 23. The second part 4B is the part from the lowest rotor blade 22 to the upper end of the rotor 4. That is, the second part 4B is the part that includes multiple stages of rotor blades 22.

[0022] The rotor 4 is made of a titanium-based material. Examples of titanium-based materials used for the rotor 4 include titanium and titanium alloys. In this embodiment, an alloy containing approximately 6% aluminum and 4% vanadium by mass fraction (sometimes called "64 titanium") can be used as the material for the rotor 4. The rotor 4 made of a titanium-based material is lightweight and has very high strength. Therefore, the performance of the vacuum pump 1 can be greatly improved compared to conventional vacuum pumps 1, such as by allowing the rotor 4 to rotate at a higher speed.

[0023] Titanium-based materials are difficult to process using mechanical methods that employ cutting tools. On the other hand, additive manufacturing is a method of forming articles of a desired shape by irradiating metal powder with laser light, electron beams, etc., according to the desired shape, thereby melting and solidifying the powder. Therefore, even articles with complex shapes can be easily formed using titanium-based materials.

[0024] Therefore, the first part 4A, which has a simple, almost cylindrical shape, can be formed relatively easily and quickly even by mechanical processing. On the other hand, the second part 4B, which has a complex shape and includes multiple stages of rotor blades 22, can be formed relatively easily by additive manufacturing. Although additive manufacturing makes it difficult to increase the formation speed because it builds up powder layers sequentially to form an object, by using additive manufacturing only for the second part 4B and not for the entire rotor 4, the second part 4B can be formed in a relatively short time compared to when the entire rotor 4 is formed by additive manufacturing. In addition, since the amount of powder material used for layering can be saved, the manufacturing cost of the rotor 4 can be reduced compared to when the entire rotor 4 is formed by additive manufacturing.

[0025] Thus, by separating the rotor 4 into a part formed by mechanical processing (first part 4A) and a part formed by material lamination (second part 4B), the rotor 4 can be manufactured easily and quickly while reducing the amount of shavings compared to when the entire rotor 4 is formed by mechanical processing. Furthermore, the rotor 4 can be manufactured in a shorter time and at a lower cost compared to when the entire rotor 4 is formed by additive manufacturing.

[0026] Furthermore, instead of forming the entire rotor 4 using additive manufacturing, forming a portion of the rotor 4 by mechanical processing allows for the precise formation of the second part 4B by additive manufacturing and the accurate determination of the processing origin in various processes. The processing origin is determined based on the surface of the workpiece, but if the processing origin is determined on a part formed by additive manufacturing, it cannot be accurately determined. This is because the surface of the part formed by additive manufacturing has many irregularities, and the processing origin determined on that part may differ depending on the position where it is determined. Also, additive manufacturing cannot achieve the same dimensional accuracy as mechanical processing.

[0027] On the other hand, parts formed by mechanical processing have fewer surface irregularities and higher dimensional accuracy. Therefore, by setting the processing origin based on any position in the part formed by mechanical processing (first part 4A), the processing origin can be accurately set to its intended location.

[0028] The manufacturing method for the rotor 4 described above will now be explained. First, an example of an additive manufacturing apparatus 100 for forming the second part 4B by additive manufacturing will be explained using Figure 3. Figure 3 is a diagram showing an example of an additive manufacturing apparatus 100. The additive manufacturing apparatus 100 has a first chamber R1 and a second chamber R2 formed by three walls W arranged at predetermined intervals.

[0029] A material mounting section 101 is located in the first chamber R1. The material mounting section 101 is movable vertically along the wall W in the first chamber R1. In the first chamber R1, the space from the upper end of the material mounting section 101 to slightly above the upper end of the wall W is filled with a first material M (in this embodiment, titanium alloy powder) used to form the second section 4B.

[0030] A processing object placement section 102 is located in the second chamber R2. A processing object for laminating the first material M is placed in the processing object placement section 102. In the processing object placement section 102, the processing object is positioned such that its upper surface is slightly below the upper surface of the wall W. The processing object placement section 102 is movable vertically along the wall W in the second chamber R2.

[0031] The additive manufacturing apparatus 100 has a material extrusion unit 103. The material extrusion unit 103 is movable in the lateral direction and extrudes the first material M, which is filled in the first chamber R1 and is located slightly above the upper surface of the wall W, toward the second chamber R2, supplying it to the upper surface of the workpiece placed in the workpiece placement unit 102.

[0032] The additive manufacturing apparatus 100 includes an irradiation unit 104 and a mirror 105. The irradiation unit 104 generates a beam L that melts the powder of the first material M supplied to the upper surface of the workpiece. The beam L that melts the powder of the first material M is, for example, laser light. In this case, the irradiation unit 104 is a laser oscillator that generates laser light.

[0033] The mirror 105 reflects the beam L irradiated from the irradiation unit 104 toward the first material M of powder supplied to the upper surface of the workpiece. The mirror 105 is rotatable around multiple axes (for example, vertical axes and horizontal axes) by means of a galvanometer scanner, for example, and can reflect the beam L to any position on the workpiece. In this way, the beam L can be irradiated to any position on the workpiece, allowing the additive manufacturing apparatus 100 to form articles of any shape.

[0034] The manufacturing method of the rotor 4 will be explained in detail using Figure 4. Figure 4 is a flowchart of the manufacturing method of the rotor 4. First, the first part 4A of the rotor 4 is formed by cutting, as shown in Figure 5A (step ST1). In addition, holes are drilled for mounting positions of parts, etc., as needed. Figure 5A is a diagram showing an example of the formation of the first part 4A. As shown in Figure 5A, the first part 4A is cylindrical in shape and can be formed relatively easily and quickly by mechanical processing such as cutting, even when formed from titanium-based materials that are difficult to process.

[0035] Next, the second part 4B is formed on the upper end of the first part 4A formed in step ST1 by additive manufacturing (step ST2). Specifically, the second part 4B is formed as follows. First, the first part 4A formed in step ST1 is placed in the workpiece placement section 102 of the additive manufacturing apparatus 100. In the workpiece placement section 102, the first part 4A is positioned so that its upper end surface coincides with the upper end surface of the workpiece placement section 102. The workpiece placement section 102 is also positioned so that its upper end surface is slightly below the upper end surface of the wall W.

[0036] As described above, when the first part 4A is placed in the processing target placement section 102, the processing origin for forming the second part 4B by additive manufacturing is determined. However, in the case of the first part 4A formed by mechanical processing, the processing origin can be accurately determined. As a result, the formation of an inappropriate second part 4B, such as due to misalignment of the layers, can be prevented.

[0037] Subsequently, the material extrusion unit 103 of the additive manufacturing apparatus 100 is moved toward the second chamber R2 to extrude and supply the first material M filled in the first chamber R1 to the second chamber R2. As described above, the upper end surface of the first portion 4A is positioned to coincide with the upper end surface of the workpiece placement unit 102, and the upper end surface of the workpiece placement unit 102 is located slightly below the upper end surface of the wall W. Therefore, when the material extrusion unit 103 supplies the first material M to the second chamber R2, the upper end surfaces of the workpiece placement unit 102 and the first portion 4A are supplied with the first material M in a thickness corresponding to the distance between the upper end surface and the upper end surface of the wall W. In other words, in one process of additive manufacturing, a portion of the second portion 4B with a thickness corresponding to the distance between the upper end surface and the upper end surface of the wall W is formed on the upper end surface of the first portion 4A.

[0038] After supplying the first material M to the upper surface of the workpiece placement section 102 and the first part 4A, a beam L is generated from the irradiation section 104 and the mirror 105 is rotated as appropriate to irradiate the first material M on the upper surface of the workpiece placement section 102 and the first part 4A with the beam L according to the shape (cross-sectional shape) of a part of the second part 4B to be formed by the current process of additive manufacturing, thereby melting and solidifying the first material M and forming a part of the second part 4B.

[0039] After forming a portion of the second part 4B, the material extrusion section 103 is returned to the end of the first chamber R1 (the left end in Figure 3), and the material placement section 101 of the first chamber R1 of the additive manufacturing apparatus 100 is raised so that the first material M in the first chamber R1 protrudes above the upper surface of the wall W. Meanwhile, the workpiece placement section 102 is lowered so that the upper surface of the portion of the second part 4B formed in this process is moved to a position slightly below the upper surface of the wall W.

[0040] Subsequently, the following steps are repeated until the entire second part 4B is formed (i.e., "No" in step ST3): (i) the first material M from the first chamber R1 is supplied to the upper surface of a part of the second part 4B (and the upper surface of the workpiece placement section 102); (ii) the beam L is irradiated according to the shape of a part of the second part 4B to melt and solidify the first material M supplied to the upper surface; and (iii) the material placement section 101 of the additive manufacturing apparatus 100 is raised and the workpiece placement section 102 is lowered.

[0041] In Figures 5A to 5D, solid lines (without internal hatching) indicate already formed portions, areas enclosed by thick solid lines and hatched with diagonal lines indicate portions formed in this process, and dashed lines indicate unformed portions. Figures 5B to 5D schematically show the process by which the second portion 4B is formed by laminating the first material M.

[0042] After forming the second part 4B, the rotor 4 is finished (step ST4). Here, "finishing" is performed by mechanical processing, such as using a lathe to eliminate surface irregularities of the rotor 4 (especially the second part 4B) and to adjust the dimensions of the rotor 4. Finishing is not limited to these, but is particularly performed on the contact areas with the shaft 21 (e.g., the surface P1 that contacts the shaft 21 (Figure 2), the protruding part P2 that fits onto the shaft 21 (Figure 2)), and the mounting surfaces of various parts (e.g., the surface P3 (Figure 2)). This is done, for example, to ensure proper connection (fitting) between the rotor 4 and the shaft 21, to balance the rotor 4, and to ensure that the axis center of the shaft 21 and the center of the rotor 4 coincide without error. Additionally, if necessary, drilling holes for mounting parts is performed as part of the finishing process.

[0043] For the reasons stated above, it is preferable to perform finishing work after accurately determining the machining origin. Accordingly, if it is necessary to hold or place the rotor 4 during finishing work, the first portion 4A of the rotor 4, which is formed by mechanical machining, should be held or placed on it. Furthermore, the machining origin should be determined based on the surface of the first portion 4A, which is formed by mechanical machining. For example, the position of the workpiece when it is in contact with the surface of the first portion 4A can be determined as the machining origin.

[0044] By setting the machining origin for the finishing process based on the surface of the first part 4A, the rotor 4 can be finished to the intended dimensions. This allows for proper connection between the rotor 4 and the shaft 21, and enables the manufacture of a rotor 4 with little to no imbalance in the rotor 4 or misalignment between the center of the shaft 21 and the center of the rotor 4.

[0045] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention.

[0046] In the above embodiment, the first part 4A of the rotor 4 was the entire rotor cylindrical portion 23. However, it is not limited to this. For example, as shown in Figure 6, the first part 4A may be the connection portion 23a of the rotor cylindrical portion 23 to the lowest rotor blade 22. Figure 6 shows another embodiment of the first part 4A. This makes it possible to reduce the vertical dimension of the first part 4A, and thus reduce the vertical dimension of the workpiece placement section 102 of the additive manufacturing apparatus 100. As described above, when placing the first part 4A in the workpiece placement section 102, it is necessary to align the upper end surface of the workpiece placement section 102 with the upper end surface of the first part 4A. For this reason, if the first part 4A is the entire rotor cylindrical portion 23, it is necessary to make the vertical dimension of the workpiece placement section 102 the same as the dimension of the entire rotor cylindrical portion 23. On the other hand, if the first part 4A is designated as the connecting part 23a, the vertical dimension of the workpiece placement section 102 can be made smaller, matching the dimension of the connecting part 23a, which is smaller than the entire rotor cylindrical section 23.

[0047] Furthermore, if the first part 4A is used as the connecting part 23a, the amount of material to be formed by mechanical processing can be reduced, thus shortening the manufacturing time of the rotor 4.

[0048] Furthermore, if the first part 4A is used as the connecting part 23a, as shown in Figure 6, the rotor cylindrical part 23 can be formed by fixing another cylindrical part 23b to the lower end of the connecting part 23a, which is the first part 4A. By forming the rotor cylindrical part 23 separately into the connecting part 23a and the cylindrical part 23b in this way, the rotor cylindrical part 23 can be formed from a more optimal material. The cylindrical part 23b can be made of a carbon material such as graphite, for example. By making the cylindrical part 23b from a carbon material, the rotor cylindrical part 23 can be made lighter (i.e., the entire rotor 4 can be made lighter).

[0049] In addition to the entire rotor cylindrical portion 23, the first portion 4A formed by mechanical machining may also include several stages (about one or two stages) of rotor blades 22 at the bottom. If the rotor blades 22 are included in this first portion 4A, the machining tool can be brought relatively easily close to the rotor blade 22 formation area, thus allowing the rotor blades 22 to be formed by mechanical machining.

[0050] The rotor cylindrical portion 23 may be provided with a through hole that penetrates from its outer circumference to its inner circumference. This allows the exhaust gas to be exhausted not only from the gap between the rotor cylindrical portion 23 and its outer circumference and the stator cylindrical portion 32, but also from the gap between the inner circumference of the rotor cylindrical portion 23 and the base 3. This through hole can be formed by mechanical processing (drilling).

[0051] When forming the second part 4B, the beam L irradiated to melt the powdered first material M is not limited to laser light, but can also be an electron beam.

[0052] The method for forming the second part 4B is not limited to the method using the additive manufacturing apparatus 100 described above (i.e., the powder bed method). For example, a method in which the first material M is deposited and solidified by irradiating it with laser light or the like while spraying it with powder (metal deposition method), a method in which the molten first material M is extruded from a nozzle or the like to form the second part 4B (ADAM method), or a method in which a binder (liquid binder) is sprayed onto the powder of the first material M to solidify it (binder jet method) can be employed.

[0053] The rotor 4 can also be made of other metals such as aluminum, depending on its application. Even when using other metals, the entire rotor 4 can be manufactured by forming the first part 4A of the rotor 4 by mechanical processing and the second part 4B by material lamination (additive manufacturing), as described above.

[0054] Furthermore, the first part 4A and the second part 4B can be formed from different materials, for example, by forming the first part 4A from an aluminum alloy and the second part 4B from a titanium alloy. For example, the first part 4A can be formed from a first titanium alloy, and the second part 4B can be formed from a second titanium alloy with a different alloy composition from the first titanium alloy. In other words, it is preferable to select a titanium alloy suitable for machining as the first titanium alloy and a titanium alloy suitable for additive manufacturing as the second titanium alloy.

[0055] Those skilled in the art will understand that the above-described exemplary embodiments are specific examples of the following embodiments.

[0056] (First Embodiment) A method for manufacturing a rotor (e.g., rotor 4) having rotor blades (e.g., rotor blades 22) and a rotor cylindrical portion (e.g., rotor cylindrical portion 23) comprises the following steps. The following (a) and (b) do not limit the order in which they are performed. (a) A step (e.g., step ST1) in which a first portion (e.g., first portion 4A) including at least a portion of the rotor cylindrical portion is formed by mechanical processing. (b) A step of stacking a second part (e.g., second part 4B) including rotor blades onto the first part (e.g., steps ST2 to ST3).

[0057] In the rotor manufacturing method according to the first embodiment, a first portion of the rotor, including at least a part of the rotor cylindrical portion, is formed by mechanical processing, and the remaining portion of the rotor, i.e., the second portion including the rotor blades, is formed by laminating it onto the first portion. The first portion, including at least a part of the rotor cylindrical portion, has a simple shape and can be formed easily and quickly by mechanical processing. On the other hand, the second portion, including the rotor blades, has a complex shape but can be easily formed by laminating it onto the first portion. When forming the entire rotor by lamination, it takes a long time and requires a lot of material, but by laminating only the second portion, the processing time can be reduced. In addition, since a lot of material is not required, the manufacturing cost of the rotor can be reduced.

[0058] In this way, by separating the rotor manufacturing process into a part formed by mechanical processing (first part) and a part formed by lamination (second part), the rotor can be manufactured easily and quickly while reducing the amount of shavings compared to when the entire rotor is formed by mechanical processing. Furthermore, the rotor can be manufactured in a shorter time and at a lower cost compared to when the entire rotor is formed by lamination.

[0059] (Second Embodiment) In the rotor manufacturing method according to the first embodiment, the first material (for example, first material M) laminated to the first part may be a titanium-based material. In the rotor manufacturing method according to the second embodiment, a rotor that is lightweight and has very high strength can be manufactured, so the performance can be greatly improved compared to conventional vacuum pumps, such as by allowing the rollers to rotate at a higher speed in the vacuum pump. Furthermore, although titanium-based materials are difficult to process by mechanical processing methods, by using a lamination method, even if the first material laminated to form the second part is a titanium-based material, a second part with a complex shape can be easily formed.

[0060] (Third Embodiment) The rotor manufacturing method according to the first or second embodiment may further include a step (for example, step ST4) in which a machining origin is set based on a first part formed by mechanical machining, and at least a second part is finished. In the rotor manufacturing method according to the third embodiment, the rotor can be finished to the intended dimensions, so a rotor can be manufactured with little to no deviation in rotor balance or deviation of the center of rotor 4.

[0061] (Fourth aspect) In the rotor manufacturing method according to any of the first to third aspects, the first part may be the entire rotor cylindrical portion. In the rotor manufacturing method according to the fourth aspect, the entire rotor cylinder can be formed with high precision.

[0062] (Fifth Embodiment) In the rotor manufacturing method according to any of the first to third embodiments, the first part may be the part of the rotor cylindrical portion that is connected to the rotor blades (for example, the connecting portion 23a). In the rotor manufacturing method according to the fifth embodiment, the dimensions of the part (for example, the part to be processed arrangement 102) where the first part is placed in the apparatus for forming the second part (for example, the additive manufacturing apparatus 100) can be reduced. Also, since the amount of part to be formed by mechanical processing can be reduced, the rotor manufacturing time can be shortened.

[0063] (Sixth aspect) The method for manufacturing a rotor according to the fifth aspect may further include the step of forming a rotor cylindrical portion by attaching a predetermined member (for example, a cylindrical portion 23b) to the first portion. In the method for manufacturing a rotor according to the sixth aspect, the rotor cylindrical portion can be formed from a more optimal material.

[0064] (Seventh aspect) In the rotor manufacturing method according to the sixth aspect, the predetermined member may be made of carbon material. In the rotor manufacturing method of the seventh aspect, the rotor cylindrical portion can be made lighter (i.e., the rotor can be made lighter). [Explanation of symbols]

[0065] 1: Vacuum pump 2: Housing 3: Bass 4: Rotor 5: Status 11:First end 12:Second end 13: Air intake 14: Base end 15: Exhaust vent 21: Shaft 21A: Thrust Disc 21B: Target 22: Rotor blades 22a: Center 22b: Wings 221 :1st part 223 :Second part 225: Connection part 227 :Curve part M1: 1st material M2: 2nd material 23: Rotor cylindrical section 31: Stator Wing 32: Stator cylindrical section 41A: Bearing 41B: Magnetic bearing 41C: Magnetic bearing 41D: Magnetic bearing 41E: Bearing 42: Motor 42A: Motor Rotor 42B: Motor stator A1: Axial direction S1: 1st internal space S2: Exhaust space

Claims

1. A method for manufacturing a rotor having rotor blades and a rotor cylindrical portion, The steps include forming a first portion, which includes at least a part of the rotor cylindrical portion, by mechanical processing, The steps include forming the second portion, which includes the rotor blades, by stacking it on the first portion, A method for manufacturing a rotor, comprising the same components.

2. The method for manufacturing a rotor according to claim 1, wherein the first material laminated on the first portion is a titanium-based material.

3. The method for manufacturing a rotor according to claim 1, further comprising the step of determining a machining origin with respect to the first portion formed by mechanical processing, and finishing processing at least the second portion.

4. The method for manufacturing a rotor according to claim 1, wherein the first portion is the entire rotor cylindrical portion.

5. The method for manufacturing a rotor according to claim 1, wherein the first portion is the portion of the rotor cylindrical portion that is connected to the rotor blades.

6. The method for manufacturing a rotor according to claim 5, further comprising the step of forming the rotor cylindrical portion by attaching a predetermined member to the first portion.

7. The method for manufacturing a rotor according to claim 6, wherein the predetermined member is made of carbon material.

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