Rotor and vacuum pump

Abstract

A rotor for vacuum pumps and preferably turbomolecular pumps, comprising a support member connectable to a rotor shaft having a plurality of rotor blades, each of the plurality of rotor blades comprising a plurality of layers perpendicular to the axial direction of the rotor, each of the plurality of layers being at least partially formed as an arcuate curve connected at a respective end to the support member, the plurality of layers being arranged laterally offset with respect to each other.

Description

Technical Field

[0001] The present invention preferably relates to a rotor for a turbomolecular pump and a vacuum pump provided with such a rotor.

Background Art

[0002] Known vacuum pumps comprise a housing having an inlet and an outlet. A rotor assembly is disposed within the housing and is rotated by an external power source such as an electric motor. At least one rotor element is attached to a rotor shaft, and rotation of the rotor assembly conveys a gaseous medium from the inlet to the outlet. In that regard, the rotor element may in particular be made of one or more rotor disks for a turbomolecular pump. In that regard, the rotor disk usually comprises a plurality of inclined surfaces made as blades in order to provide a pumping action. Known pumps have a plurality of pump stages, and each pump stage for a turbomolecular pump is composed of at least one rotor disk interacting with at least one stator element coupled to the housing.

[0003] Due to the high-speed rotation of the rotor assembly, high structural requirements are imposed on the components of the rotor blades. In that regard, the centrifugal force acting on the rotor blades usually limits the rotational speed of the vacuum pump and thereby simultaneously limits the maximum performance of the vacuum pump. Therefore, there is a need for rotor blades with high structural stability.

[0004] However, increasing the structural stability of the rotor increases the weight of the rotor assembly. This leads to higher requirements for the bearings and increases the cost of the vacuum pump. Also, this increases the stored energy of the rotor, which may limit the pump's performance and raise concerns about safety.

[0005] It is well known that composite materials, particularly carbon fiber reinforced plastics (CFRP), have the potential to significantly improve upon the limitations mentioned above. CFRP is widely used in TMP's Holweck skit, but not in the rotor's turbo blade section. The reason lies in its complex design and the resulting high manufacturing costs. The connection point between the radially oriented blades and the circumferentially oriented hub has been identified as a weak point. Mitigating this weakness increases the cost and weight of the rotor disc. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Therefore, the objective of the present invention is to provide a rotor assembly that is easy to manufacture, lightweight, and cost-effective. [Means for solving the problem]

[0007] This objective is achieved by the rotor described in claim 1 and the vacuum pump described in claim 19.

[0008] In one aspect of the present invention, a rotor for a turbomolecular pump is provided. Often, the rotor assembly consists of one or more rotor disks. The rotor disks, also known as blade disks or “blisks,” form the rotor elements of one pump stage of a vacuum pump. The rotor disks of the rotor can be manufactured individually and assembled onto a rotor shaft. Alternatively, two or more rotor disks can be manufactured integrally, preferably monolithically. The rotor disk comprises a support member that can be coupled to the rotor shaft. In this regard, the support member typically has a circular or substantially circular opening that is coupled to the rotor shaft of the vacuum pump. However, other shapes of openings are also possible. Generally, the opening of the support member has a shape that conforms to the shape of the rotor shaft in order to transmit the rotation of the rotor shaft to the support member and, as a result, to the rotor disk. Furthermore, the rotor disk includes a plurality of rotor blades. In this regard, each of the plurality of rotor blades includes a plurality of layers perpendicular to the axial direction of the rotor disk.

[0009] Here and below, the axial direction is defined by the axial direction of the rotor shaft, i.e., it coincides with the axis of rotation of the rotor. The transverse direction is the in-plane direction perpendicular to the axial direction.

[0010] Multiple layers are arranged along the rotor shaft in their assembled state. In this respect, each of the multiple layers relating to one of the multiple rotor blades is formed as at least partially arched curves, and each arched curve is coupled to a support member at its respective end. The multiple layers relating to one rotor blade are arranged offset from each other laterally or angularly. In other words, the arched curves of one layer on each blade relative to the arched curves of another layer are arranged offset from each other in the circumferential direction. Thus, the series of layers, and the laterally or angular offsets between each layer, create an angled surface that provides a pumping action when the rotor disk rotates. In detail, the arched curves of the multiple layers relating to one rotor blade are coupled to each other axially, creating a closed surface or sidewall, the shape of which follows the outer shape and internal line of the arched curve of the individual layers and is inclined with respect to the axial direction of the rotor disk. Accordingly, the present invention modifies the conventional blade shape of the rotor disc, thereby avoiding the problems of the prior art for connecting such conventional rectangular rotor blades to a support member. Thus, an alternative design is implemented that provides high structural stability, which can be easily carried out using carbon fiber reinforced plastic or other materials.

[0011] In another aspect of the present invention, a rotor for a turbomolecular pump is provided. Often, the rotor assembly consists of one or more rotor discs. The rotor discs of the rotor can be manufactured individually and assembled to a rotor shaft. Alternatively, two or more rotor discs can be manufactured integrally, preferably monolithically. The rotor discs form the rotor elements of one pump stage of a vacuum pump. The rotor discs include support members that can be coupled to a rotor shaft. In this regard, the support members typically have circular or substantially circular openings that are coupled to the rotor shaft of the vacuum pump. However, other shapes of openings are also possible. Generally, the openings of the support members have a shape that conforms to the shape of the rotor shaft in order to transmit the rotation of the rotor shaft to the support members and, as a result, to each rotor disc. Furthermore, the rotor discs include a plurality of rotor blades.

[0012] In this respect, each of the multiple rotor blades forms at least a partially curved portion in a cross section in a plane perpendicular to the axial direction, and the curved portion is coupled to a support member at each end. The curved portions of the first and second cross sections, located at different positions along the axial direction of the same blade, are positioned angularly offset from each other. Multiple cross sections can be defined that are positioned along the axial direction. Multiple curved cross sections relating to one rotor blade are positioned laterally or angularly offset from each other. In other words, the curved portion of one cross section relative to the curved portion of another cross section is positioned circumferentially offset from each other. Thus, the series of curved cross sections, and the lateral or angular offsets between each cross section, create an angled surface that provides a pumping action when the rotor disk rotates.

[0013] In detail, a third cross section can be defined, and the first, second, and third cross sections are arranged in a continuous order along the axial direction, and the angular or lateral offset between each arched curve of the first and second cross sections is in the same direction as the angular or lateral offset between each arched curve of the second and third cross sections, so as to form a continuous shape of the blade.

[0014] In detail, the multiple arched sections of a single rotor blade are joined to each other in the axial direction to form a closed surface or side wall, the shape of which follows the outer and inner lines of the arched sections of the individual sections and is inclined with respect to the axial direction of the rotor disc. Thus, the present invention modifies the conventional blade shape of the rotor disc, thereby avoiding the problems of the prior art for joining such conventional rotor blades to a support member. Accordingly, an alternative design is implemented that provides high structural stability, which can be easily carried out with carbon fiber reinforced plastic or other materials.

[0015] Preferably, the present invention requires an anisotropic material, such as having superior mechanical properties in one or two spatial directions.

[0016] Preferably, the arched curved portion is configured to exhibit only tensile forces parallel to the arched curve. Thus, the force is applied only along the direction of the maximum possible strain of the material, ensuring optimal force transmission and thereby improving the structural stability of the individual blades and rotor discs.

[0017] Preferably, the individual layers / sections of multiple rotor blades are arranged on a common plane or alternately on subsequent planes. For example, the first layer / section of one rotor blade is located on the same plane as the first layer / section of another rotor blade. Alternatively, in another example, the first layer / section of one rotor blade is located on a plane directly preceding the plane in which the section of another rotor blade is located. This arrangement enables a layered structure that simplifies the manufacturing process.

[0018] Preferably, the rotor disk is manufactured by an additive manufacturing method such as molten filament manufacturing.

[0019] Preferably, at least one of the rotor blades has a wall thickness or density that varies along the curved portion. Thus, the wall thickness can vary along the length of the curved portion, from the first end of the curved portion to the second end of the curved portion, which is connected to the support member. Preferably, the variation is symmetrical between the first end of the curved portion and the tip of the curved portion, which is the tip of the rotor blade. However, the thickness can also vary multiple times along each rotor blade.

[0020] Preferably, the thickness of the rotor blade is varied to change the shape of the curved section while maintaining only the tensile force of the curved section.

[0021] Preferably, the thickness of the rotor blade is varied such that it is thickest at the leading and / or trailing edge of each rotor blade and thinnest at the tip of the blade.

[0022] Preferably, the wall thickness of one rotor blade differs from that of another rotor blade. Thus, each rotor blade may have a similar structure in terms of its wall thickness, or different blades may have different wall thicknesses. Therefore, the wall thickness can be freely selected to improve pump performance and reduce the weight of the rotor disc while maintaining the structural stability of the rotor disc.

[0023] Preferably, each of the multiple rotor blades includes the same number of layers. Alternatively, at least two of the multiple rotor blades include different numbers of layers. In this regard, individual rotor blades can be manufactured in different ways, having different structural shapes to suit specific needs with respect to pump performance and structural stability.

[0024] Preferably, the lateral or angular offset of the plurality of layers / cross-sections is constant for each of the layers / cross-sections. Alternatively, the lateral or angular offset between the plurality of layers / cross-sections is different and can vary from one layer / cross-section to another. Thus, by changing the lateral or angular offset between the layers / cross-sections, the shape of the individual blades in the axial direction can be adapted to specific needs regarding pump performance and structural stability.

[0025] Preferably, the lateral or angular offset is the same for each of the plurality of rotor blades. Alternatively, at least two rotor blades implement different lateral or angular offsets from one of their layers / cross-sections to another, specifically with respect to the corresponding layers / cross-sections. Thus, the individual rotor blades can be made similarly or differently with respect to their lateral offset, i.e., their axial shape. The lateral offset can determine the inclination of each blade. Increasing the offset reduces the inclination. By implementing different lateral offsets for different blades, different inclinations can be provided that are adapted to each application in order to improve pump performance. The inclination can be defined as the angle between the blade surface and a plane perpendicular to the axis of rotation.

[0026] Preferably, the inclination of the wall of each of the plurality of rotor blades, i.e., the angle between the wall and a plane perpendicular to the axis of rotation, decreases as the distance from the support member to the tip of the rotor blade increases. Thereby, the high-speed rotating part at the tip of the individual rotor blade can have different wall inclinations that increase the pump performance of the rotor disk.

[0027] Preferably, each of the arcuate curvatures comprises a first end and a second end coupled to the support member, and the first end and the second end are spaced apart from each other. Thus, the arcuate curvature does not end at the position where it starts from the support member. Thereby, a sling defined by the arcuate curvature of the individual layer is created.

[0028] Preferably, the first and second ends of the arcuate bends of one blade, preferably two or more blades, more preferably all blades, are coupled to the support member at positions facing each other along the outer periphery of the support member. Accordingly, an optimal force transfer of the rotational force from the individual blades to the support member becomes possible, and at the same time, the tangential coupling of the individual blades to the support member can be made more stable.

[0029] Preferably, each of the arcuate bends of one layer / cross-section, preferably having a first end and a second end coupled to the support member, is combined with the arcuate bends of all the blades of each respective layer / cross-section to form a continuous line. Accordingly, the arcuate bends in the common layer / cross-section of all the blades can be called a hypotrochoid or are in a continuous shape that looks very similar. In that regard, the arcuate shape can be formed, for example, by continuous fibers of a fiber-reinforced plastic. In other words, the second end of the first blade coincides with the first end of another blade and continues until the second end of the last blade coincides with the first end of the first blade. In that regard, preferably, at the position where the first end of one blade coincides with the second end of another blade, there is no kink in the transition portion, that is, it has the same inclination / curvature. In other words, the first derivative at the first end of one blade is equal to or approximately equal to the derivative at the second end of the other blade. In that regard, specifically, each arcuate bend can extend along the outer surface of the support member in order to increase the contact surface between the blade and the support member. In other words, the first end of one blade can be coupled to the second end of the other blade respectively by an intermediate section, and the intermediate section can form the support member. The intermediate section can extend along the shape of the support member, and all the intermediate sections or the combination of all the layers / cross-sections can form the support member. This combination of arcuate bends shows an improvement in durability and strength, and at the same time, the manufacturing is simple.

[0030] Preferably, the number of tips / slings / blades

number

number

number

[0031] Preferably, each of the arched curves has a first end and a second end connected to a support member, and the first and second ends of one blade are directly connected by the first and second ends of the opposing blades. Thus, the arched curves of two opposing blades are directly connected, and their shapes can be made by combining them with a continuous sling. Alternatively, the arched curves of two opposing blades are connected by an intermediate section, which can form a support member. In other words, the second end of the first blade is connected to the first end of the opposing second blade by an intermediate section, and the second end of the second blade is connected to the first end of the first blade by an intermediate section. The intermediate section can extend along the shape of the support member, and any combination of all intermediate sections or any combination of layers / sections can form a support member.

[0032] Preferably, each of the arched curves comprises a first end and a second end connected to a support member, the first and second ends being in the same axial position. Thus, the arched curves terminate at the same axial position or axial height from the support member. In detail, each individual layer of the arched curve is perpendicular to the axis of rotation.

[0033] Preferably, each of the arched curves comprises a first end and a second end connected to a support member, the first and second ends being at different axial positions. Thus, the arched curves do not terminate at the same axial position or axial height from the support member. This creates a sling defined by the individual layers of arched curves. In detail, each individual layer of the arched curve is inclined around an axis perpendicular to the axial direction. Thus, the resulting blade shape can be adapted to specific needs, thereby optimizing the rotor performance.

[0034] Preferably, the reinforcing elements of each blade follow the curved portion. More specifically, the projection of the reinforcing elements of each blade onto a plane perpendicular to the axial / rotation axis follows the curved portion.

[0035] Preferably, with respect to a single rotor blade, at least one layer / section, preferably two or more, and most preferably all layers / sections, have a parabolic or substantially parabolic shape. In this regard, the shape of the arched curve is defined by a parabolic function to ensure that the tensile force is parallel to the arched curve. More specifically, if the first and second ends of each arched curve are in different axial positions, the axial projection of the arched curve has a parabolic or substantially parabolic shape. In this regard, the axial projection is defined as the projection along the axial direction of the rotor shaft.

[0036] Preferably, with respect to a single rotor blade, at least one layer / section, preferably two or more, and most preferably all layers / sections, have a catenary or substantially catenary shape. In this regard, the shape of the arched curve is defined by a catenary function to ensure that the tensile force is parallel to the arched curve. In this regard, the catenary function is usually proportional to the cosh function. More specifically, if the first and second ends of each arched curve are in different axial positions, the axial projection of the arched curve has a catenary or substantially catenary shape. In this regard, the axial projection is defined as the projection along the axial direction of the rotor shaft.

[0037] Preferably, with respect to a single rotor blade, at least one layer / section, preferably two or more, and most preferably all layers / sections, have a troposkeleton shape or a substantially troposkeleton shape. In this regard, the shape of the arched section is defined by a troposkeleton function to ensure that the tensile forces are parallel to the arched section. In this regard, the troposkeleton function is usually proportional to the Jacobian elliptic sine function (denoted by "sn" and also called sinus amplitudinis). More specifically, if the first and second ends of each arched section are in different axial positions, the axial projection of the arched section has a troposkeleton shape or a substantially troposkeleton shape. In this regard, the axial projection is defined as the projection along the axial direction of the rotor shaft.

[0038] Preferably, with respect to one rotor blade, at least one layer / section, preferably two or more, and most preferably all layers / sections, have a hypotrochoidal or substantially hypotrochoidal shape. In this respect, the shape of the arched curve is defined by a hypotrochoid to ensure that the tensile forces are parallel to the arched curve. More specifically, if the first and second ends of each arched curve are in different axial positions, the axial projection of the arched curve has a hypotrochoidal or substantially hypotrochoidal shape. In this respect, the axial projection is defined as the projection along the axial direction of the rotor shaft.

[0039] Preferably, with respect to one rotor blade, at least one layer / section, preferably two or more, most preferably all layers / sections, have a symmetrical shape, which is perpendicular to the axial direction and mirrored along a line connecting the axis of rotation and the point of the shape furthest from the axis of rotation. The lengths of the shapes on both sides of the mirror axis may or may not be equal.

[0040] Preferably, each blade is made at least partially from fiber-reinforced plastic (FRP), such as carbon fiber or glass fiber FRP. More specifically, the rotor, i.e., the rotor disc, is made entirely from FRP.

[0041] Preferably, the rotor, or rotor disc, is monolithic.

[0042] Preferably, the arched curved portion can be made of sling or long fibers. More preferably, continuous fibers can be used. Alternatively, closed sling material can be used to enhance the structural stability of the individual blades.

[0043] Preferably, the fibers are arranged along each arched curve. This ensures optimal force transmission from the tip of each blade to the support member.

[0044] Preferably, the fiber projections onto each cross-section are arranged along the curved portion.

[0045] Preferably, each of the multiple layers is made from at least partially a metal band. The metal band or metal band improves stability in one or two directions (directions perpendicular to the width of the band). In addition, the metal band has a high capacity to withstand tensile forces applied along the length of the band material. Thus, each layer can be made by band material that connects the individual layers to each other in order to create the shape of individual blades.

[0046] Preferably, the curved portions of multiple rotor blades are arranged either overlapping or spaced apart in a plane perpendicular to the axial direction or on the surface of a mathematical cone having circular symmetry, so that the rotor's axis of rotation coincides with the cone's line of symmetry. Therefore, the curved portion of one rotor blade may be separated from the curved portion of another adjacent rotor blade, or adjacent rotor blades may overlap.

[0047] Preferably, the length of the curved section may vary within a single rotor blade, from one layer / section to another. This allows the radial extension of individual blades to be tailored to specific needs.

[0048] Alternatively, the length of the curved section can be constant across all layers / sections of a single blade.

[0049] Preferably, the shape of the arched curve can vary from one layer / section to another of a particular rotor blade, thereby allowing the shape of individual rotor blades to be adapted in the axial direction.

[0050] Preferably, all blades on a single rotor disc are the same shape. Alternatively, at least two rotor blades are made to have different shapes.

[0051] In another object of the present invention, a vacuum pump is provided comprising at least one rotor disk as described above. In this, the rotor disk is coupled to the rotor shaft of the vacuum pump and is preferably rotated by an electric motor. Thereafter, the rotor disk interacts with a stator element coupled to the housing of the vacuum pump to produce a pumping action, carrying gas from the inlet to the outlet of the vacuum pump.

[0052] Preferably, the vacuum pump comprises a plurality of rotor disks as described above, more specifically, a rotor disk each interacting with an individual stator. In this regard, the plurality of rotor disks can be made identically, or the shape of the rotor disks can be varied.

[0053] The present invention will be described in more detail below with reference to the accompanying drawings. [Brief explanation of the drawing]

[0054] [Figure 1] This shows a vacuum pump according to one embodiment of the present invention. [Figure 2A] Details of the rotor disk according to the present invention are illustrated below. [Figure 2B] Details of the rotor disk according to the present invention are illustrated below. [Figure 2C] Details of the rotor disk according to the present invention are illustrated below. [Figure 3A] This is an embodiment of a detailed view of a cross-section, layer, or layer projection of a rotor disk according to the present invention. [Figure 3B] This is an embodiment of a detailed view of a cross-section, layer, or layer projection of a rotor disk according to the present invention. [Figure 4A] This is a diagram of Embed Design. [Figure 4B] This is a diagram of Embed Design. [Figure 5A] This is a diagram of another embodiment of the present invention. [Figure 5B] This is a diagram of another embodiment of the present invention. [Figure 6A] This is a diagram of another embodiment of the present invention. [Figure 6B] This is a diagram of another embodiment of the present invention. [Figure 7] This is a flowchart of the manufacturing method according to the present invention. [Modes for carrying out the invention]

[0055] Referring to Figure 1, a vacuum pump constructed as a turbomolecular pump is shown. The vacuum pump comprises a housing 10 including an inlet 12 and an outlet 14. A rotor shaft 16 is located within the housing, and the rotor shaft 16 is supported by a first radial bearing 18, constructed as a permanent magnet bearing in the example of Figure 1, and a mechanical ball bearing 31. The first radial bearing 18 comprises several magnet rings 22, 23. In this respect, the stationary magnet ring 26 of the radial bearing 18 is attached to a trunnion 24 that extends into a recess of the rotor shaft 16. The rotating magnet ring 22 is located radially adjacent to the stationary magnet ring 26 on the inner surface of the recess.

[0056] Furthermore, the radial bearing 18 includes an emergency operating bearing 30 (upper) made as a ball bearing. The rotor shaft 16 is driven by an electric motor 32. The rotor shaft 16 is fitted with several pump elements made as a rotor disk 34, which are coupled to the housing 10 of the vacuum pump and interact with stator elements 36 that are arranged alternately with the rotor disk 34. In addition, the vacuum pump of Figure 1 includes a Holbeck stage 38 which includes a rotating cylinder 40 that interacts with a threaded stator 42 coupled to the housing. The rotation of the rotor shaft 16 carries the gaseous medium from the inlet 12 to the outlet 14 of the vacuum pump.

[0057] Refer to Figures 2A-2C. According to the present invention, the rotor disc 34 comprises a support member 100 having an angular or nearly angular opening 101. The support member 100 can be attached to the rotor shaft 16 of the rotor assembly to couple the rotor disc 34 or blade disc to the rotor shaft 16. Refer to Figure 2B, which shows a detailed view of the rotor disc 34. An arched curved portion 102 is attached to the support member 100 in the first layer, with the first end 102A and the second end 102B of the arched curved portion 102 being attached to the support member 100, separated from each other. The arched curved portion has a defined width W, which defines the thickness of the side wall and encloses and creates an opening 103. Furthermore, the arched curved portion has a defined height in the axial direction. Thus, the arched curved portion 102 of the first layer forms part of the side wall or inclined wall that provides the pumping effect of the rotor disc. As shown in Figure 2C, the arched curve 102 of the first layer is repeated in the subsequent second layer, resulting in a second arched curve 104, which is axially displaced relative to the arched curve 102 of the first layer and offset laterally or angularly relative to the arched curve 102 of the first layer. Furthermore, Figure 2C shows a third arched curve 106 in the third layer. In this regard, only one rotor blade is shown in Figures 2B and 2C for simplification and illustrative purposes. However, the blade disk can comprise multiple rotor blades. The arched curves 102, 104, and 106 of the different layers are coupled to each other, creating a side wall or solid surface that provides a pumping effect when the rotor disk rotates in a vacuum pump. In this regard, the side wall can be made stepped, resulting in a stepped inclined wall. Alternatively, the side wall can be continuous, resulting in a smooth surface. In this regard, each rotor blade comprises multiple layers. In Figure 2C, three layers are illustrated for simplification and illustrative purposes, but the number of layers can exceed 20, preferably more than 50, and more preferably more than 100. Subsequent layers provide continuous coupling of each arched curve. In detail, there is no space between the individual subsequent layers and each arched curve to form a closed surface for pumping.

[0058] In other words, if the rotor is not constructed in layers in detail, the cross-section of the plane perpendicular to the axial direction is considered a layer. In this respect, the axial direction corresponds to the axial direction and the axis of rotation of the rotor shaft. As described above and with respect to layers, in each cross-section, the blades are made up of arched curves such as the arched curves 102, 104, and 106 shown in Figures 2A to 2C. Consequently, below, layers can be replaced with cross-sections.

[0059] In detail, if the rotor is made of long fibers, thin strips, or continuous fiber reinforcement, the projection of this reinforcement onto a plane perpendicular to the axis of rotation follows the shape of the arc-shaped curve described by the present invention.

[0060] Figures 2B and 2C show that the thickness of the sidewalls formed by the arched curves 102, 104, and 106 is constant, that is, W shown in Figure 2B is constant along the entire arched curve. However, in another embodiment, the thickness of the sidewalls formed by the arched curves 102, 104, and 106 can vary along the individual arched curves 102, 104, and 106, or it can provide a wall thickness that increases or decreases axially by varying from one layer to another.

[0061] Furthermore, Figure 2C shows that the length and shape of the arched curves 102, 104, and 106 are identical. However, in another embodiment, in order to adapt the shape of the blade 105 to the axial direction, the length or shape of either or both of the arched curves 102, 104, and 106 can vary from one layer to another.

[0062] The shapes of the arched curves 102, 104, and 106 can be given by parabolic functions. Alternatively, the arched curves may have a shape given by a catenary curve containing a cosh function, or by a troposkeleton or a very similar shape. A predetermined selection of the shapes of the arched curves 102, 104, and 106 allows all tensile forces introduced to a particular blade 105 by the rotation of the rotor disc to be parallel to the arched curves and therefore parallel to the direction of the highest possible tensile force of the material. Thus, if the arched curves are made of, for example, fiber-reinforced plastic, the fibers, especially long fibers or continuous fibers, or closed fiber loops, extend along the arched curves, providing structural stability in the direction of the tensile force, thereby improving the structural stability of the rotor blade. As a result, higher rotational speeds can be applied to a particular rotor blade, improving pumping performance. Thus, by moving away from conventional blade designs in which rectangular blades are coupled to annular support structures, a stable and easily manufactured rotor disc can be realized. As illustrated by arrow 107 in Figure 2C, as the rotor disk rotates, the inclined surface 109 pumps the particles of the gaseous medium toward the outlet of the vacuum pump.

[0063] Figure 3A shows a first embodiment, in which the rotor blades 108, 108' are exemplified by their arched curves. In detail, the rotor disk in Figure 3A may have more than 6 rotor blades, more than 10 rotor blades, and so on. However, in the embodiment of Figure 3A, the arched curves of the individual rotor blades 108, 108' do not intersect with each other, but are coupled to the support member 100 at a distance from each other.

[0064] In another embodiment shown in Figure 3B, five blades 110 are evenly distributed around the support member 100, and the arc-shaped curves of the rotor blades 110 in this embodiment intersect with each other.

[0065] Figures 3A and 3B show that individual rotor blades 108, 108', and 110 can have the same size and shape, but of course, different rotor blades can have different sizes and shapes to provide optimized pumping action through the individual inclined surfaces of the rotor disc.

[0066] Referring to Figures 4A and 4B, a complete rotor disc 34 of another embodiment is shown, having 11 blades 112 in two projections. In this respect, the thickness of the sidewalls is selected to be constant at 0.1–5 mm, preferably 0.5–2 mm. Furthermore, the blades create a plurality of openings 144 having inclined surfaces 116 that provide a pumping action to the particles of the gaseous medium. In this respect, the inclined surfaces 116 have an inclination of 10° to 65°, preferably 10° to 20°, with respect to the axial direction in the example of Figures 4A and 4B. Furthermore, as shown in Figure 4A, the outer rim 113 of the rotor disc 34 is substantially circular to prevent backflow of the gaseous medium in the vacuum pump between individual pump stages. However, when the number of blades is small, filler elements can be provided between the blades to ensure a circular or at least substantially circular correction of the rotor disc 34, so that the outer rim is close to the housing of the vacuum pump when assembled.

[0067] Referring to embodiments in Figures 5A and 5B, a rotor disc according to the present invention is shown having only six blades 114 that bring inclined surfaces within a plurality of openings 154, the inclined surfaces having an inclination between 10° and 65°, preferably between 15° and 30°, with respect to the axial direction to provide optimal pumping efficiency. In this respect, the arched curve of one blade is seamlessly coupled to the arched curve of the opposing blade in the layer or cross section. Thus, the reinforcing element used to form the blades 114 can be provided as a sling that simultaneously provides two opposing blades.

[0068] Preferably, the axial width of the rotor disc is between 1 mm and 35 mm, more preferably between 5 mm and 15 mm. The outer diameter of the rotor disc is preferably between 50 mm and 400 mm, more preferably between 70 mm and 300 mm.

[0069] As shown in Figures 4A, 4B, 5A, and 5B, the rotor disc can be made from carbon fiber reinforced plastic (CFRP) which preferably contains long fibers, more preferably continuous fibers, to create the arched curves of the individual layers. In this regard, a closed sling can also be used in the examples of Figures 5A and 5B to produce the opposing rotor blades in one go.

[0070] Preferably, an additive manufacturing method, more specifically a fiber-reinforced fused filament manufacturing method, can be used to manufacture each rotor blade. In this regard, the arched curves of each blade in the first layer are arranged in a common plane and manufactured in the first step. Subsequently, the arched curves of all blades in the subsequent layers are manufactured, and as a result, each rotor disc can be manufactured layer by layer. In particular, to further enhance the structural stability of the rotor disc when using continuous carbon fibers or closed slings of carbon fibers, these carbon fibers can be woven together, more specifically, at the intersections of individual blades.

[0071] Preferably, a filament winding process can be used to manufacture each rotor blade. In this regard, one or more mandrel parts are used to wind the material into the desired shape. Unlike commonly used filament winding processes, this mandrel may not be perfectly convex in the winding direction. Manufacturing such rotor blades that require a concave mandrel may require more than two axes of motion between the filament source and the mandrel.

[0072] Referring to embodiments in Figures 6A and 6B, a rotor disc according to the present invention is shown having nine blades 114 that bring inclined surfaces into a plurality of openings 154, the inclined surfaces having inclinations between 10° and 65°, preferably between 15° and 30°, with respect to the axial direction to provide optimal pumping efficiency. Figure 6A shows a combined arc-shaped curved section of one common layer or cross section. As shown, the arc-shaped curved section is connected to a single line. The endpoint of one blade becomes the starting point of another blade, and the endpoint of the last blade becomes the starting point of the first blade. In that respect, the curved section may be characterized by following a shape that resembles or substantially resembles a hypotrochoid. Reinforcement elements may be provided as a continuous sling that brings all the blades together. This improves the load balance within the rotor and enhances the durability and strength of the rotor. Figure 6B is a perspective view of the rotor of Figure 6A.

[0073] Referring to Figure 7, a flowchart of the method for manufacturing a blade disk according to the present invention is shown. This method is S01: A step of providing a support member for connecting the rotor disc to the rotor shaft, S02: A step of providing a curved portion to each of the rotor blades of the rotor disc, S03: The step of repeating the arc-shaped curve of the first layer in subsequent layers, offsetting it angularly with respect to the preceding layer, S04: Following arrow 600, the step of repeating step S03 multiple times to produce a rotor disk layer by layer in order to obtain the final rotor disk 602, Includes.

[0074] As described above, the arched shapes of the individual blades provided in step S02 do not need to be identical, nor do the arched shapes repeated in different layers provided in step S03 need to be identical. The length, side wall thickness, or shape of each arched curve can be adapted to improve the stability, pumping performance, or both of the rotor disc.

[0075] Therefore, by deviating from the conventional shape of the rotor disc, and more specifically its blades, structural stability can be improved, and as a result, higher rotational speeds can be applied without damaging the rotor. Alternatively, this concept can be used to manufacture rotor blades with smaller mass and / or lower second moment of inertia, thereby increasing rotational speeds. Alternatively, this concept can be used to utilize materials that could not be used for the impeller due to mechanical strength in at least one spatial direction. In particular, the arched curve is configured such that the tension in the direction of the material's highest strength is always, or at least substantially, parallel to the arched curve, thus improving the connection point between the individual blades and the support members.

Claims

1. A rotor for a turbomolecular pump, A support member that can be coupled to a rotor shaft having an axial direction, Multiple rotor blades, Equipped with, Each of the plurality of rotor blades has at least a partially curved portion in a cross-section in a plane perpendicular to the axial direction, and each of the curved portions is connected to a support member at its respective end, and the curved portions are configured to exhibit only a tensile force parallel to the curved portion due to the rotation of the rotor. A rotor in which the arc-shaped curved portions of the first and second cross-sections of each blade are arranged to be angularly offset from one another.

2. A rotor for a turbomolecular pump, A support member that can be connected to the rotor shaft, Multiple rotor blades, Equipped with, Each of the aforementioned rotor blades includes multiple layers, Each of the aforementioned layers is formed at least partially as an arched curved portion, the arched curved portion is coupled to the support member at each end, and the arched curved portion is configured to exhibit only a tensile force parallel to the arched curved portion due to the rotation of the rotor. A rotor in which the aforementioned multiple layers of each blade are arranged to be offset from one another in the angular direction.

3. The rotor according to claim 2, wherein each of the plurality of layers is made at least partially from fiber-reinforced plastic (FRP) material.

4. The rotor according to claim 3, wherein the FRP material includes continuous fibers or closed sling material.

5. The rotor according to claim 2, wherein each of the plurality of layers is made of at least partially metal bands.

6. The rotor according to claim 2, wherein one or more of the lengths and shapes of the arc-shaped curves of each of the plurality of layers of a single rotor blade vary between each end of the arc-shaped curve.

7. The rotor according to claim 1, wherein each of the plurality of rotor blades has a side wall in a cross-section in a plane perpendicular to the axial direction that forms the arched curve, the side wall having a wall thickness in the cross-section, the wall thickness varying along the arched curve and / or varying with respect to at least two cross-sections of the same rotor blade.

8. The rotor according to claim 1, wherein each of the plurality of rotor blades has a side wall that forms the arc-shaped curved portion in a cross-section in a plane perpendicular to the axial direction, the side wall has a wall thickness in the cross-section, the side wall has a constant thickness, or at least two of the plurality of rotor blades have side walls of different thicknesses.

9. The rotor according to claim 2, wherein the angular offset of the plurality of layers is constant, or the angular offset of the plurality of layers is different.

10. The rotor according to claim 1, wherein each of the plurality of rotor blades has a side wall that forms the arc-shaped curved portion in a cross-section in a plane perpendicular to the axial direction, and the inclination of the side wall decreases as the distance from the support member to the tip of each of the rotor blades increases.

11. The rotor according to claim 1, wherein each of the plurality of rotor blades is formed such that, in each of the plurality of cross-sections perpendicular to the rotation axis of the rotor, the rotor blade has a mirror-symmetric shape along a line perpendicular to the rotation axis and extending from the rotation axis to the tip of the rotor blade.

12. The rotor according to claim 1, wherein each of the arc-shaped curved portions comprises a first end and a second end connected to the support member, and the first end and the second end are spaced apart from each other.

13. The rotor according to claim 1, wherein each end of the arch-shaped curved portion extends tangentially to the support member.

14. The rotor according to claim 1, wherein each of the arched curved portions has a first end and a second end, the arched curved portions of all blades are combined to form a continuous line, the first end of one blade is connected to the second end of another blade by an intermediate section, and the intermediate section can form the support member.

15. The rotor according to claim 1, wherein each of the arched curved portions has a first end and a second end, and the arched curved portions of opposing blades around the outer circumference of the support member are combined to form a continuous line, the first end of one blade is connected to the second end of another blade by an intermediate section, and the intermediate section can form the support member.

16. The rotor according to any one of claims 1 to 15, wherein the arc-shaped curved portion has a parabolic shape.

17. The rotor according to any one of claims 1 to 15, wherein the arched curved portion has a catenary shape.

18. The rotor according to any one of claims 1 to 15, wherein the arched curved portion has a troposkeleton shape.

19. The rotor according to any one of claims 1 to 15, wherein the arc-shaped curved portion has a hypotrochoid shape.

20. The rotor according to claim 1, wherein the arc-shaped curved portions of the plurality of rotor blades overlap in a plane perpendicular to the axial direction or are arranged at intervals from one another.

21. A vacuum pump comprising the rotor according to any one of claims 1 to 15.

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