Vacuum pump and vacuum pump component

Abstract

[Problem] To provide a vacuum pump having superior mechanical characteristics. [Solution] Provided is a turbo-molecular pump that includes a rotor blade 114 disposed on a rotor shaft and rotating together with the rotor shaft, and that exhausts a process gas by the rotation of the rotor shaft with exhaust elements (such as a rotary turbine blade 102 and a rotor body 103a) provided on the rotor blade. The rotor blade 114 is made from a first metal material and a second metal material, and at least some of constituent parts are produced using a 3D printer. A portion to be a joint 212 of the first metal material and the second metal material has an inclusion coupling structure in which one of the first metal material and the second metal material contains at least a portion of the other.

Description

Vacuum pumps and vacuum pump components

[0001] The present invention relates to vacuum pumps, such as turbomolecular pumps, and vacuum pump components.

[0002] Turbomolecular pumps are a type of vacuum pump commonly used for exhausting gases from manufacturing equipment for semiconductors, flat panels, etc. Turbomolecular pumps use a motor inside the pump body to rotate rotors, which ejects gas molecules from the gas (process gas) drawn into the pump body.

[0003] Furthermore, Patent Document 1, which is listed below, discloses that the rotor disk (66) or the stator disk (68) can be manufactured by fused deposition modeling, 3D printing, or the like, and can be composed of two or more material layers.

[0004] Japanese Patent Application Laid-Open No. 2016-205391

[0005] Incidentally, Patent Document 1 states in paragraph 0015 that "These component layers can be connected to one another by lamination (lamination processing, German: Laminieren). In this case, the component layers can be made individually and then joined or laminated to one another later." It also states in paragraph 0019 that "In particular, various material combinations can be intended in the component. One region of the component can be made of, for example, one powder material, while another region is made of, for example, another powder material. The first region of the component can be made of, for example, aluminum, and the second region of the component can be made of, for example, titanium. In this case, an aluminum-titanium transition (German: Uebergaenge) can be formed in the boundary region between both regions by intermetallic bonding."

[0006] Furthermore, in Patent Document 1, paragraph 0020 states, "The member may be formed from various powder materials. These may be combined, for example, via a buffer layer." and paragraph 0021 states, "Preferably, the member is composed of at least two, particularly laminated, member layers. These layers are then manufactured individually and arranged with each other in the above-mentioned arrangement, and are joined with each other, particularly by lamination."

[0007] However, Patent Document 1 only discloses joining or laminating individually produced component layers, and does not disclose how to improve the mechanical properties between the components, etc. Therefore, even if the manufacturing method disclosed in Patent Document 1 is adopted, the mechanical properties of the component may be insufficient.

[0008] SUMMARY OF THE INVENTION It is an object of the present invention to provide a vacuum pump and vacuum pump components having improved mechanical properties.

[0009] (1) To achieve the above object, the present invention provides a vacuum pump having a rotor blade disposed on a rotor shaft and rotating together with the rotor shaft, wherein the rotor blade exhausts gas by rotation of the rotor shaft using an exhaust element provided on the rotor blade, wherein the rotor blade is made of a plurality of metal materials, at least a portion of the constituent parts are made by fusion deposition modeling, and a portion of the joint between the plurality of metal materials has an inclusive bonding structure in which one part contains at least a portion of the other. (2) To achieve the above object, the present invention provides a vacuum pump component comprising a plurality of metal materials, at least a portion of the constituent parts are made by fusion deposition modeling, and a portion of the joint between the plurality of metal materials has an inclusive bonding structure in which one part contains at least a portion of the other.

[0010] According to the above invention, it is possible to provide a vacuum pump and vacuum pump components having superior mechanical properties.

[0011] FIG. 1 is an explanatory diagram schematically illustrating the configuration of a turbomolecular pump according to a first embodiment of the present invention. FIG. 2 is a circuit diagram of an amplifier circuit. FIG. 3 is a time chart illustrating control when a current command value is greater than a detection value. FIG. 4 is a time chart illustrating control when a current command value is smaller than a detection value. (a) is a cross-sectional view showing a joint according to a first embodiment, (b) is a cross-sectional view showing a joint according to a second embodiment, (c) is a cross-sectional view showing a joint according to a third embodiment, (d) is a cross-sectional view showing a joint according to a fourth embodiment, and (e) is a cross-sectional view showing a joint according to a fifth embodiment. (a) is a cross-sectional view showing a joint according to a sixth embodiment, (b) is a cross-sectional view showing a joint according to a seventh embodiment, (c) is a cross-sectional view showing a joint according to an eighth embodiment, and (d) is a cross-sectional view showing a joint according to a ninth embodiment. FIG. 1 is an explanatory diagram schematically illustrating a 3D printer. (a) is an explanatory diagram schematically illustrating the steps of forming each layer, (b) is an explanatory diagram illustrating another step of forming each layer, and (c) is an explanatory diagram illustrating yet another step of forming each layer. FIG. 1A is an explanatory diagram showing an embodiment in which the blade portion and the rotor main body are made of different metal materials, and FIG. 1B is an explanatory diagram showing an embodiment in which the rotor main body and the rotor lower cylindrical portion are made of different metal materials.

[0012] 1 shows a vertical cross-sectional view of a turbomolecular pump 100 as a vacuum pump according to a first embodiment of the present invention. This turbomolecular pump 100 is adapted to be connected to a vacuum chamber (not shown) of a target device such as a semiconductor manufacturing device.

[0013] 1, a turbomolecular pump 100 has an intake port 101 formed at the upper end of a cylindrical outer cylinder 127. Inside the outer cylinder 127, a rotor 103 is provided, on the periphery of which are formed a plurality of rotating turbine impellers 102 (102a, 102b, 102c, ...) which are turbine blades for sucking in and exhausting gas, arranged radially and in multiple stages.

[0014] In the following, the rotating turbine blades (turbine blade portions) of multiple stages may be collectively referred to as "rotary turbine blades 102." Furthermore, when there is no need to particularly distinguish between the rotating turbine blades (turbine blade portions) of each stage, they may be collectively referred to as "rotary turbine blades 102." Furthermore, as necessary, the rotating turbine blades (turbine blade portions) may be distinguished by stage and referred to as "rotary turbine blade 102a," "rotary turbine blade 102b," "rotary turbine blade 102c," and so on. Each stage is configured to include multiple blades (blade portions), similar to a typical turbomolecular pump. The same applies to the stationary turbine blades 123 (123a, 123b, 123c, and so on) and stationary blade spacers 125 (125a, 125b, 125c, and so on) described below.

[0015] A rotor shaft 113 is attached to the center of the rotating body 103, and this rotor shaft 113 is supported in the air by, for example, a five-axis controlled magnetic bearing, and its position is controlled. In this embodiment, the rotating body 103 has the rotor shaft 113, and the rotor shaft 113 and rotor blades 114 are combined to form the rotating body 103. The structure of the rotor blades 114 will be described in detail later.

[0016] The upper radial electromagnets 104 are arranged in pairs on the X-axis and the Y-axis. Four upper radial sensors 107 are provided adjacent to the upper radial electromagnets 104 and corresponding to each upper radial electromagnet 104. The upper radial sensors 107 are, for example, inductance sensors or eddy current sensors having conductive windings, and detect the position of the rotor shaft 113 based on changes in the inductance of the conductive windings, which change depending on the position of the rotor shaft 113. The upper radial sensors 107 are configured to detect the radial displacement of the rotor shaft 113, i.e., the rotating body 103 fixed thereto, and send the detected displacement to the control device 200.

[0017] In this control device 200, for example, a compensation circuit having a PID adjustment function generates an excitation control command signal for the upper radial electromagnet 104 based on a position signal detected by the upper radial sensor 107, and an amplifier circuit 150 (described later) shown in Figure 2 controls the excitation of the upper radial electromagnet 104 based on this excitation control command signal, thereby adjusting the upper radial position of the rotor shaft 113.

[0018] The rotor shaft 113 is made of a material with high magnetic permeability (iron, stainless steel, etc.) and is attracted by the magnetic force of the upper radial electromagnets 104. Such adjustment is performed independently in the X-axis direction and the Y-axis direction. In addition, the lower radial electromagnets 105 and the lower radial sensors 108 are arranged in the same manner as the upper radial electromagnets 104 and the upper radial sensors 107, and adjust the radial position of the lower side of the rotor shaft 113 in the same manner as the radial position of the upper side.

[0019] Furthermore, axial electromagnets 106A and 106B are arranged above and below a circular metal disk (also called an "armature disk") 111 provided at the bottom of rotor shaft 113. Metal disk 111 is made of a highly magnetic permeable material such as iron. An axial sensor 109 is provided to detect the axial displacement of rotor shaft 113, and an axial position signal from the axial sensor 109 is sent to control device 200.

[0020] In the control device 200, a compensation circuit having, for example, a PID adjustment function generates excitation control command signals for each of the axial electromagnets 106A and 106B based on the axial position signal detected by the axial sensor 109, and the amplifier circuit 150 controls the excitation of each of the axial electromagnets 106A and 106B based on these excitation control command signals, so that the axial electromagnet 106A attracts the metal disk 111 upward by magnetic force, and the axial electromagnet 106B attracts the metal disk 111 downward, thereby adjusting the axial position of the rotor shaft 113.

[0021] In this way, the control device 200 appropriately adjusts the magnetic forces that the axial electromagnets 106A and 106B exert on the metal disk 111, magnetically levitating the rotor shaft 113 in the axial direction and holding it in space without contact. The amplifier circuit 150 that controls the excitation of the upper radial electromagnet 104, the lower radial electromagnet 105, and the axial electromagnets 106A and 106B will be described later.

[0022] Meanwhile, motor 121 has a plurality of magnetic poles arranged circumferentially so as to surround rotor shaft 113. Each magnetic pole is controlled by control device 200 so as to rotate rotor shaft 113 via electromagnetic force acting between the magnetic pole and rotor shaft 113. Motor 121 also incorporates a rotational speed sensor (not shown), such as a Hall element, resolver, or encoder, and the rotational speed of rotor shaft 113 is detected by the detection signal of this rotational speed sensor.

[0023] Furthermore, a phase sensor (not shown) is attached, for example, near the lower radial sensor 108, to detect the phase of rotation of the rotor shaft 113. The control device 200 uses the detection signals of both this phase sensor and the rotational speed sensor to detect the position of the magnetic pole.

[0024] A plurality of fixed turbine blades 123 (123a, 123b, 123c...) are arranged at small gaps (predetermined intervals) from the rotating turbine blades 102 (102a, 102b, 102c...). Each of the rotating turbine blades 102 (102a, 102b, 102c...) is inclined at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113 in order to transport exhaust gas molecules downward through collision.

[0025] Similarly, the fixed turbine vanes 123 are also formed at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113, and are arranged alternately with the rows of rotating turbine vanes 102 toward the inside of the outer cylinder 127. The outer peripheral ends of the fixed turbine vanes 123 are supported by being inserted between a plurality of stacked stator vane spacers 125 (125a, 125b, 125c, ...).

[0026] The fixed vane spacer 125 is a ring-shaped member made of a metal such as aluminum, iron, stainless steel, or copper, or an alloy containing any of these metals. An outer cylinder 127 is fixed to the outer periphery of the fixed vane spacer 125 with a small gap between them. A base 129 is disposed at the bottom of the outer cylinder 127. An exhaust port 133 is formed in the base 129 and communicates with the outside. Exhaust gas that enters the intake port 101 from the chamber (vacuum chamber) and is transferred to the base 129 is sent to the exhaust port 133.

[0027] Furthermore, depending on the application of the turbomolecular pump 100, a threaded spacer 131 is disposed between the lower part of the fixed vane spacer 125 and the base portion 129. The threaded spacer 131 is a cylindrical member made of a metal such as aluminum, copper, stainless steel, iron, or an alloy containing any of these metals, and has a plurality of spiral thread grooves 131a engraved on its inner circumferential surface. The spiral direction of the thread grooves 131a corresponds to the direction in which exhaust gas molecules are transported toward the exhaust port 133 when they move in the rotation direction of the rotor 103. A rotor lower cylindrical portion 103b hangs down from the lower part of the rotor main body 103a on which the rotary turbine vanes 102 (102a, 102b, 102c, ...) of the rotor 103 are formed. The outer peripheral surface of the rotor lower cylindrical portion 103b is cylindrical and protrudes toward the inner peripheral surface of the threaded spacer 131, with a predetermined gap separating them. Exhaust gas transferred to the thread grooves 131a by the rotating turbine impellers 102 and the fixed turbine impellers 123 is guided along the thread grooves 131a and sent to the base portion 129. In this manner, the threaded spacer 131 and the opposing rotor lower cylindrical portion 103b constitute a Holweck-type exhaust mechanism 204. The Holweck-type exhaust mechanism 204 imparts directionality to the exhaust gas by the rotation of the rotor lower cylindrical portion 103b relative to the threaded spacer 131, thereby improving the exhaust characteristics of the turbomolecular pump 100.

[0028] The base portion 129 is a disk-shaped member that forms the base of the turbomolecular pump 100, and is generally made of metal such as iron, aluminum, stainless steel, etc. The base portion 129 not only physically holds the turbomolecular pump 100, but also functions as a heat conduction path, so it is desirable to use a metal that is rigid and has high thermal conductivity, such as iron, aluminum, or copper.

[0029] In this configuration, when the rotating turbine impellers 102 are rotated together with the rotor shaft 113 by the motor 121, exhaust gas is drawn from the chamber through the intake port 101 by the action of the rotating turbine impellers 102 and the fixed turbine impellers 123. The exhaust gas drawn in through the intake port 101 passes between the rotating turbine impellers 102 and the fixed turbine impellers 123 and is transferred to the base portion 129. At this time, the temperature of the rotating turbine impellers 102 rises due to frictional heat generated when the exhaust gas comes into contact with the rotating turbine impellers 102 and conduction of heat generated by the motor 121, but this heat is transferred to the stationary turbine impellers 123 side by radiation or conduction by gas molecules of the exhaust gas.

[0030] The fixed blade spacers 125 are joined together at their outer peripheries and transmit to the outside heat received by the fixed turbine blades 123 from the rotating turbine blades 102 and frictional heat generated when exhaust gas comes into contact with the fixed turbine blades 123.

[0031] In the above description, the threaded spacer 131 is disposed on the outer periphery of the rotor lower cylindrical portion 103b of the rotor 103, and the thread groove 131a is engraved on the inner circumferential surface of the threaded spacer 131. However, conversely, there are also cases where a thread groove is engraved on the outer circumferential surface of the rotor lower cylindrical portion 103b, and a spacer having a cylindrical inner circumferential surface is disposed around it.

[0032] Depending on the application of the turbomolecular pump 100, the electrical equipment section may be covered by a stator column 122 to prevent the gas sucked in from the intake port 101 from entering the electrical equipment section, which is composed of the upper radial electromagnet 104, the upper radial sensor 107, the motor 121, the lower radial electromagnet 105, the lower radial sensor 108, the axial electromagnets 106A and 106B, the axial sensor 109, etc., and the interior of this stator column 122 may be kept at a predetermined pressure by purge gas.

[0033] In this case, a purge gas introduction pipe (also referred to as a "purge gas port") 132 is provided in the base portion 129, and the purge gas is introduced through this pipe. The introduced purge gas is sent to an exhaust port 133 through gaps between the protective bearing 120 and the rotor shaft 113, between the rotor and stator of the motor 121, and between the inner cylindrical portion of the rotating turbine blades 102 (lower cylindrical portion 103b of the rotor) and the stator column 122 or the base portion 129.

[0034] Here, the turbomolecular pump 100 requires control based on specific parameters (e.g., various characteristics corresponding to the model) that are individually adjusted and specific to the model. To store these control parameters, the turbomolecular pump 100 is provided with an electronic circuit unit 141 within its body. The electronic circuit unit 141 is composed of a semiconductor memory such as an EEPROM, electronic components such as semiconductor devices for accessing the memory, and a substrate 143 for mounting these components. The electronic circuit unit 141 is housed below a rotational speed sensor (not shown) near the center of a base unit 129 that constitutes the lower part of the turbomolecular pump 100, and is closed by an airtight bottom lid 145.

[0035] In the semiconductor manufacturing process, some process gases introduced into a chamber have the property of solidifying when their pressure exceeds a predetermined value or their temperature falls below a predetermined value. Inside the turbomolecular pump 100, the pressure of the exhaust gas is lowest at the inlet 101 and highest at the outlet 133. If the pressure of the process gas exceeds a predetermined value or the temperature falls below a predetermined value while the process gas is being transferred from the inlet 101 to the outlet 133, the process gas solidifies and adheres to and accumulates inside the turbomolecular pump 100.

[0036] For example, when SiCl4 is used as the process gas in an Al etching apparatus, the vapor pressure curve shows that at low vacuum (760 torr to 10-2 torr) and low temperature (approximately 20°C), a solid product (e.g., AlCl3) precipitates and adheres to and accumulates inside the turbomolecular pump 100. As a result, when precipitates of the process gas accumulate inside the turbomolecular pump 100, these deposits narrow the pump flow path, causing a decrease in the performance of the turbomolecular pump 100. The aforementioned product is prone to solidification and adhesion in high-pressure areas near the exhaust port 133 and the threaded spacer 131.

[0037] To solve this problem, conventionally, a heater (not shown) or a circular water-cooled pipe 149 is wound around the outer periphery of the base portion 129, and a temperature sensor (e.g., a thermistor) (not shown) is embedded in the base portion 129, and heating by the heater and cooling by the water-cooled pipe 149 are controlled based on a signal from the temperature sensor to maintain the temperature of the base portion 129 at a constant high temperature (set temperature) (hereinafter referred to as TMS; Temperature Management System). In this embodiment, the threaded spacer 131 is heated by a heater (not shown) embedded in the threaded spacer 131, and the base portion 129 is cooled by the water-cooled pipe 149 embedded in the bottom cover 145.

[0038] Next, an amplifier circuit 150 that controls excitation of the upper radial electromagnets 104, the lower radial electromagnets 105, and the axial electromagnets 106A and 106B in the turbomolecular pump 100 will be described. A circuit diagram of this amplifier circuit is shown in FIG.

[0039] 2, one end of the electromagnet winding 151 constituting the upper radial electromagnet 104 and the like is connected to the positive electrode 171a of the power supply 171 via a transistor 161, and the other end is connected to the negative electrode 171b of the power supply 171 via a current detection circuit 181 and a transistor 162. The transistors 161 and 162 are so-called power MOSFETs, and have a structure in which a diode is connected between the source and drain.

[0040] At this time, the transistor 161 has a diode cathode terminal 161a connected to the positive electrode 171a and an anode terminal 161b connected to one end of the electromagnet winding 151. The transistor 162 has a diode cathode terminal 162a connected to the current detection circuit 181 and an anode terminal 162b connected to the negative electrode 171b.

[0041] Meanwhile, the current regenerating diode 165 has its cathode terminal 165a connected to one end of the electromagnet winding 151 and its anode terminal 165b connected to the negative electrode 171b. Similarly, the current regenerating diode 166 has its cathode terminal 166a connected to the positive electrode 171a and its anode terminal 166b connected to the other end of the electromagnet winding 151 via a current detecting circuit 181. The current detecting circuit 181 is configured, for example, by a Hall sensor type current sensor or an electrical resistance element.

[0042] The amplifier circuit 150 configured as described above corresponds to one electromagnet. Therefore, if the magnetic bearing is controlled in five axes and there are a total of ten electromagnets 104, 105, 106A, and 106B, a similar amplifier circuit 150 is configured for each electromagnet, and the ten amplifier circuits 150 are connected in parallel to the power supply 171.

[0043] Furthermore, the amplifier control circuit 191 is configured, for example, by a digital signal processor section (hereinafter referred to as a DSP section) not shown in the figure of the control device 200, and this amplifier control circuit 191 is configured to switch the transistors 161 and 162 on / off.

[0044] The amplifier control circuit 191 compares the current value detected by the current detection circuit 181 (a signal reflecting this current value is called a current detection signal 191c) with a predetermined current command value. Based on the comparison result, the amplifier control circuit 191 determines the magnitude of the pulse width (pulse width times Tp1 and Tp2) to be generated within a control cycle Ts, which is one period of PWM control. As a result, gate drive signals 191a and 191b having these pulse widths are output from the amplifier control circuit 191 to the gate terminals of the transistors 161 and 162.

[0045] It is necessary to control the position of the rotor 103 at high speed and with strong force when, for example, the rotor 103 passes through a resonance point during acceleration of its rotational speed or when a disturbance occurs during constant-speed operation. For this reason, a high voltage of, for example, about 50 V is used as the power supply 171 so that the current flowing through the electromagnet winding 151 can be rapidly increased (or decreased). In addition, a capacitor (not shown) is usually connected between the positive electrode 171a and the negative electrode 171b of the power supply 171 to stabilize the power supply 171.

[0046] In this configuration, when both the transistors 161 and 162 are turned on, the current flowing through the electromagnet winding 151 (hereinafter referred to as electromagnet current iL) increases, and when both are turned off, the electromagnet current iL decreases.

[0047] Furthermore, when one of the transistors 161 and 162 is turned on and the other is turned off, a so-called flywheel current is maintained. By passing a flywheel current through the amplifier circuit 150 in this manner, hysteresis loss in the amplifier circuit 150 can be reduced, and the power consumption of the entire circuit can be kept low. Furthermore, by controlling the transistors 161 and 162 in this manner, high-frequency noise such as harmonics generated in the turbomolecular pump 100 can be reduced. Furthermore, by measuring this flywheel current with the current detection circuit 181, the electromagnet current iL flowing through the electromagnet winding 151 can be detected.

[0048] That is, when the detected current value is smaller than the current command value, both transistors 161 and 162 are turned on for a time period corresponding to a pulse width time Tp1 only once during a control cycle Ts (e.g., 100 μs), as shown in Fig. 3. Therefore, the electromagnet current iL during this period increases toward a current value iLmax (not shown) that can flow from the positive electrode 171a to the negative electrode 171b via the transistors 161 and 162.

[0049] On the other hand, if the detected current value is greater than the current command value, both transistors 161 and 162 are turned off for a time period corresponding to pulse width time Tp2 only once during the control cycle Ts, as shown in Fig. 4. Therefore, the electromagnet current iL during this period decreases toward a current value iLmin (not shown) that can be regenerated from the negative electrode 171b to the positive electrode 171a via diodes 165 and 166.

[0050] In either case, after the pulse width times Tp1 and Tp2 have elapsed, one of the transistors 161 and 162 is turned on. Therefore, a flywheel current is maintained in the amplifier circuit 150 during this period.

[0051] 1 (the side of the intake port 101) serves as an intake section connected to the target device, and the lower side (the side on which the exhaust port 15 constituting the exhaust port 133 is provided on the base portion 129 so as to protrude to the right in the figure) serves as an exhaust section connected to an auxiliary pump (back pump) or the like (not shown). The turbomolecular pump 100 can be used in an inverted, horizontal, or inclined position in addition to the vertical position shown in Figure 1.

[0052] In the turbomolecular pump 100, the aforementioned outer cylinder 127 and base portion 129 are combined to form a single case. Hereinafter, the outer cylinder 127 and base portion 129 may be collectively referred to as the "casing" or the "main body casing." Alternatively, only the outer cylinder 127 or only the base portion 129 may be referred to as the "casing." The turbomolecular pump 100 is electrically (and structurally) connected to a box-shaped electrical equipment case (not shown), and the aforementioned control device 200 is incorporated into the electrical equipment case.

[0053] The internal configuration of the main body casing of the turbomolecular pump 100 (here, a combination of the outer cylinder 127 and the base portion 129) can be divided into a rotation mechanism portion 136 that rotates the rotor shaft 113 and the like using the motor 121, and an exhaust mechanism portion 137 that is rotationally driven by the rotation mechanism portion 136. The exhaust mechanism portion 137 can also be divided into a turbomolecular pump mechanism portion (turbomolecular pump portion) 138 that is composed of the rotating turbine impeller 102, the fixed turbine impeller 123, and the like, and a thread groove pump mechanism portion (Hollweck-type exhaust mechanism portion 204) that is composed of the rotor lower cylindrical portion 103b, the threaded spacer 131, and the like.

[0054] The aforementioned purge gas (protective gas) is used to protect the bearing parts, the rotating turbine blades 102, etc., to prevent corrosion caused by the exhaust gas (process gas), and to cool the rotating turbine blades 102. This purge gas can be supplied by a general method.

[0055] For example, the aforementioned purge gas port 132 extending linearly in the radial direction is provided at a predetermined position (such as a position 90 degrees or 120 degrees away from the exhaust port 133) of the base portion 129. Then, purge gas is supplied to this purge gas port 132 from the outside of the base portion 129 via a purge gas cylinder (such as an N2 gas cylinder) or a flow rate regulator (valve device).

[0056] The protective bearings 120 described above are also called "touchdown (T / D) bearings," "backup bearings," etc. These protective bearings 120 prevent the position and attitude of the rotor shaft 113 from changing significantly, even in the unlikely event of a problem with the electrical system or atmospheric inrush, thereby preventing damage to the rotating turbine blades 102 and their surrounding areas.

[0057] In FIG. 1 showing the structure of the turbo molecular pump 100 and the rotor 103, hatching showing cross sections of components is omitted to avoid cluttering the drawing.

[0058] <Configuration of Rotor 114> As described above, the rotor 114 is combined with the rotor shaft 113 and rotates together with the rotor shaft 113. The rotor 114 has a rotor main body 103a and a rotor lower cylindrical portion 103b, and a large number of rotary turbine blades 102 (102a, 102b, 102c, ...) are integrally formed with the rotor main body 103a. Then, as the rotor shaft 113 rotates, gas (exhaust gas, process gas) is exhausted by an exhaust element 116 provided on the rotor 114.

[0059] The exhaust element 116 provided on the rotor 114 includes, for example, portions and components (parts) of the rotor 114 that come into contact with gas (exhaust gas, process gas) and are directly involved in exhaust. Specifically, the exhaust element 116 includes, for example, the rotating turbine blades 102 (102a, 102b, 102c, ...), the rotor main body 103a, and the rotor lower cylindrical portion 103b.

[0060] The rotor 114 is made of a plurality of metal materials, and at least some of the components (parts that make up the rotor 114) are manufactured by fused deposition modeling. Furthermore, the turbomolecular pump 100 has a structure (an inclusion-type joining structure) in which a portion of the plurality of metal materials is joined by being enclosed within the portion (an inclusion-type joining structure).

[0061] 5(a) to 5(e) and 6(a) to 6(d) show various embodiments in which the rotor 114 is made of multiple metal materials (here, two types of metal materials: first and second metal materials). Furthermore, FIGS. 5(a) to 5(e) and 6(a) to 6(d) show examples in which the rotor turbine blade 102a (as well as the rotor turbine blades 102b, 102c, etc. in other stages) and the cylindrical rotor main body 103a are made of different types (dissimilar) of metal materials. The rotor main body 103a may also be formed by combining annular (cylindrical) rotor spacers (not shown) in the axial direction that support the rotor turbine blades 102 (102a, 102b, 102c, etc.).

[0062] 5(a) to 5(e) and 6(a) to 6(d) show enlarged views of various embodiments of a joint 212 between one rotating turbine blade (referred to here as the "blade portion 102a") in one stage of rotating turbine blades (rotary turbine blade portion) 102 and the cylindrical rotor main body 103a that serves as a support portion. Furthermore, in FIGS. 5(a) to 5(e) and 6(a) to 6(d), the blade portion 102a and the rotor main body 103a are indicated by hatching.

[0063] In the following, we will explain the inclusion bonding structure between one blade portion 102a and the support portion of the blade portion 102a (here, the rotating body main body 103a), but it is also possible to adopt a similar inclusion bonding structure for other blade portions 102a of the same stage, or for all or part of blade portions 102b, 102c, etc. of other stages, and their support portions.

[0064] In the example of Fig. 5(a) (first embodiment), the cross section of the blade portion 102a is formed in a rectangular shape, and the base end portion 214 of the blade portion 102a is inserted into a recessed portion 216 of the rotating body 103a. The recessed portion 216 of the rotating body 103a is formed to match the shape of the base end portion 214 of the blade portion 102a. The base end portion 214 and the recessed portion 216 are in close contact and joined together so as to leave no gap.

[0065] The metallic material of the blade portion 102a may be, for example, a metallic material having a greater strength (such as tensile strength) than the rotor main body 103a. Furthermore, the metallic material of the blade portion 102a may be a metallic material having a smaller linear expansion coefficient than the rotor main body 103a, or a metallic material having a smaller (or larger) specific gravity. Furthermore, the metallic material of the rotor main body 103a may be a metallic material having a higher heat resistance or a higher linear expansion coefficient than the blade portion 102a. These relationships may also be applied between the rotary turbine impeller (rotary turbine impeller portion) 102 and the rotor main body (cylindrical portion) 103a, and between the rotor main body 103a and the rotor lower cylindrical portion 103b.

[0066] For example, aluminum (usually an aluminum alloy) can be used as the metallic material for the rotary turbine blades 102a, and stainless steel (usually a stainless steel alloy) can be used as the metallic material for the rotor body 103a. In this case, a metallic material with a relatively low specific gravity (and density) is used for the rotary turbine blades 102a, and a metallic material with a relatively high specific gravity is used for the rotor body 103a. This results in a weight distribution for the rotor blades 114 in which the specific gravity is lighter on the radially outer side and heavier on the radially inner side. Furthermore, a structure is obtained in which the tensile strength of the base portion (here, the rotor body 103a) supporting the rotary turbine blades 102a is greater than that of the rotary turbine blades 102a. This is particularly noticeable when a stainless steel alloy (e.g., SUS630) with a relatively high strength-to-weight ratio is used.

[0067] In addition to the combination of aluminum as the metallic material for the rotary turbine blades 102a and stainless steel as the metallic material for the rotor body 103a, various other combinations are possible. For example, the metallic material for the rotary turbine blades 102a can be a magnesium alloy and the metallic material for the rotor body 103a can be an aluminum alloy. Furthermore, the metallic material for the rotary turbine blades 102a can be an aluminum alloy or magnesium alloy and the metallic material for the rotor body 103a can be a titanium alloy or nickel alloy. Furthermore, the metallic material for the rotary turbine blades 102a can be an aluminum alloy or magnesium alloy and the metallic material for the rotor body 103a can be a stainless steel alloy with a high strength-to-weight ratio, such as SUS630. The advantages of using dissimilar materials will be described in detail below.

[0068] As described above, at the joint 212 between the blade portion 102a and the rotor main body 103a, a structure (an inclusion bonded structure) is formed in which a portion made of one metal material is bonded to a portion made of the other metal material by enclosing it within itself. The "inclusion bonded structure" referred to here can be explained as a structure in which one (portion made of a metal material) wraps around the other (portion made of a metal material) within itself, and the two (one and the other) are bonded together. In other words, the one (portion made of a metal material) fits into the inside (recess) of the other (portion made of a metal material), and the two (one and the other) are bonded together in a hook-like manner with no gaps between them.

[0069] Such "embodied bonded structures" are formed by fused deposition modeling (FDM). Examples of FDM include 3D printers, which melt and layer materials to form structures. 3D printers create three-dimensional structures based on digital models containing three-dimensional information. 3D printers are also called additive manufacturing machines, AM (Additive Manufacturing) machines, etc.

[0070] <Example of 3D Printer 280> Any 3D printer can be used as the 3D printer according to this embodiment as long as it can form an "encapsulated bonded structure" using multiple metal materials. Examples of 3D printer methods that can be used include the FDM (Fused Deposition Modeling, registered trademark) method (also known as the FFF (Fused Filament Fabrication) method).

[0071] FIG. 7 schematically illustrates an example of the basic configuration of a 3D printer (three-dimensional modeling apparatus) 280 using the FDM method. The 3D printer 280 includes a first filament supply unit 282A and a second filament supply unit 282B (not shown). In FIG. 7, only the first filament supply unit 282A is shown, with the second filament supply unit 282B hidden behind the first filament supply unit 282A. A first filament 284A containing a binder is delivered from the first filament supply unit 282A. A second filament 284B containing a binder is delivered from the second filament supply unit 282B (not shown).

[0072] The 3D printer 280 extrudes the first filament 284A from the first head 286A while melting it with heat, and stacks each layer to form a three-dimensional object. The molding material is bonded by using a heat source to melt the first filament 284A, which contains a binder.

[0073] The 3D printer 280 includes a second head unit 286B, and switches the head unit in use from the first head unit 286A to the second head unit 286B as needed. Furthermore, the 3D printer 280 may also switch the head unit in use from the second head unit 286B to the first head unit 286A.

[0074] The 3D printer 280 extrudes the second filament 284B from the second head 286B while melting it with heat, similar to the first filament 284A, and stacks each layer to form a three-dimensional object. The bonding of the modeling material is performed by melting the second filament 284B, which contains a binder, using a heat source.

[0075] The 3D printer 280 is provided with a table unit 278 that can move up and down in the Z-axis direction, and modeling is performed on the table unit 278. The table unit 278 descends as modeling progresses, making it possible to maintain or adjust the distance between the first head unit 286A and the second head unit 286B.

[0076] A first filament 284A and a second filament 284B made of different types of metal materials are individually supplied to the first head unit 286A and the second head unit 286B. The first filament 284A (or the second filament 284B) to be used for 3D printing is then guided to the printing position, and 3D printing is performed using a filament (the first filament 284A or the second filament 284B) made of a metal material appropriate for the portion of the object to be printed (here, the rotor 114). For example, the metal material of the first filament 284A can be stainless steel, and the metal material of the second filament 284B can be aluminum.

[0077] The first head unit 286A and the second head unit 286B are guided by the drive mechanism 238 within a horizontal plane (within the XY plane) and move together. For example, when forming an "inclusion bonded structure" such as the example shown in FIG. 5A, metal material can be layered in the order shown schematically in FIG. 8A. In this case, the 3D printer 280 scans the first head unit 286A (and the second head unit 286B) in the direction indicated by arrow A, for example. Then, the portion 218A that will become the rotor main body 103a is formed first, and then the portion 218B that will become the rotary turbine blade 102a is formed as part of the same layer (lower layer) 218.

[0078] When forming the next layer (upper layer) 219, the first head unit 286A (and the second head unit 286B) are scanned again, for example, in the direction indicated by arrow A. Then, a portion 219A that will become the rotor main body 103a is formed first, and then a portion 219B that will become the rotary turbine blade 102a is formed as part of the same layer (upper layer 219). In this case, a portion 219A (or portion 219B) of the upper layer 219 made of the same metal material is stacked on top of a portion 218A (or portion 218B) of the lower layer 218.

[0079] Depending on the part to be formed, the position of the end (end in the scanning direction) of part 218A (or part 218B) in the lower layer 218 and the position of the end (end in the scanning direction) of part 219A (or part 219B) in the upper layer 219 may be different (may be shifted in the scanning direction).

[0080] The first head unit 286A (and the second head unit 286B) may also be scanned in the direction indicated by arrow B. In this case, the portion 218B of the lower layer 218 that will become the rotary turbine blade 102a is formed first, and then the portion 218A that will become the rotor main body 103a is formed. Then, when forming the upper layer 219, the portion 219B that will become the blade portion 102a is formed first, and then the portion 219A that will become the rotor main body 103a is formed.

[0081] Furthermore, the scanning direction of the first head unit 286A (and the second head unit 286B) may be different for the lower layer 218 and the upper layer 219. For example, when forming the lower layer 218, the first head unit 286A (and the second head unit 286B) may be scanned in the direction indicated by arrow B, and when forming the upper layer 219, the first head unit 286A (and the second head unit 286B) may be scanned in the direction indicated by arrow A.

[0082] Furthermore, depending on the portion of the rotor 114, it is also possible to perform a shape as schematically shown in Fig. 8(b) . In the example of Fig. 7(b) , for the lower layer 220, the first head unit 286A (and the second head unit 286B) is scanned in the direction indicated by arrow A, and a portion 220A that will become the rotor main body 103a is formed. Next, for the upper layer 221, the first head unit 286A (and the second head unit 286B) is scanned in the same direction indicated by arrow A, and a portion 221A that will become the rotor main body 103a and a portion 221B that will become the blade portion 102a are formed in that order.

[0083] Here, in Figure 8(b), as in the example of Figure 8(a), the scanning direction of the first head unit 286A (and the second head unit 286B) can be set in the direction of arrow B, or the scanning direction can be changed alternately for each layer.

[0084] Furthermore, depending on the portion of the rotor 114, it is also possible to perform a shaping as shown schematically in Fig. 8(c) . In the example of Fig. 8(c) , a portion 222A1 that will become the rotor main body 103a is formed as part of one layer 222, and then a portion 222B1 that will become the blade portion 102a is formed as part of the same layer 222. Next, a portion 222A2 that will become the rotor main body 103a is formed as part of the same layer 222, and then a portion 222B2 that will become the blade portion 102a is formed as part of the same layer 222.

[0085] In the 3D printer 280, by appropriately combining layers such as those shown in Figures 8(a) to (c) as examples, it is possible to form the "contained bonded structure" of this embodiment, which has no gaps and has a complex uneven shape.

[0086] The 3D printer 280 may have the following functions. For example, the 3D printer 280 may include a drive mechanism that guides the first head unit 286A and the second head unit 286B with high positioning accuracy. Although not shown, the drive mechanism that guides the first head unit 286A and the second head unit 286B may include, for example, a stepping motor with an encoder or a linear guide. In this manner, when switching between the first filament 284A and the second filament 284B or when replacing the first filament 284A (or the second filament 284B), it is possible to accurately connect the previously modeled portion to the subsequent modeling.

[0087] The 3D printer 280 may also be equipped with a table heater (reference numeral omitted) capable of heating the table 278. In this case, the table 278 can be heated to a predetermined temperature (for example, approximately 100°C or higher). By appropriately heating the table 278, the temperature difference between the material (model) and the table 278 can be reduced, preventing the model from shrinking excessively due to a temperature drop.

[0088] The table 278 may be made of a material with sufficient thermal conductivity (e.g., aluminum). Furthermore, the table 278 may be made of a material with a sheet having a moderately fine irregularity on its surface, which enhances the fixation of the object. The irregularity of the sheet ensures a large contact area between the object and the table 278, preventing deformation of the object.

[0089] The 3D printer 280 may be equipped with an internal heater (reference numeral omitted) that can heat the interior of the chamber (the space where the modeling is performed) to a predetermined temperature (for example, about 70°C or higher). By heating the interior of the chamber, it is possible to prevent the temperature of the modeled object from dropping and causing excessive shrinkage.

[0090] Regarding the bonding of the modeling materials layered by the 3D printer 280, it is also possible to sinter the model that has been solidified using a binder.

[0091] <Details of the Inclusion Bonding Structure> The "inclusion bonding structure" as described above includes a structure in which a portion made of one metal material and a portion made of the other metal material are intertwined. In the example of Fig. 5(a), the "intricate structure" here means a state in which the blade portion 102a is inserted into the rotor main body 103a, and when a moment with the base end 214 as a fulcrum acts on the blade portion 102a, the rotor main body 103a supports the blade portion 102a.

[0092] Furthermore, the "intricate structure" means that the blade portion 102a and the rotor main body 103a are not only formed into flat plates and stacked, but also that a portion of the blade portion 102a (and / or a portion of the rotor main body 103a) has bent portions (including bent portions, stepped portions, etc.) that interlock with each other and are in close contact with each other.

[0093] The term "inclusion bonded structure" also includes a structure in which multiple metal materials form a mechanically bonded structure. The "mechanically bonded structure" used here refers to a structure in which multiple metal materials are bonded together without using mechanical fasteners such as bolts.

[0094] Generally, methods for joining metal materials are broadly classified into mechanical joining, material joining, and chemical joining. Of these, mechanical joining includes bolting, riveting, shrink fitting, cold fitting, and caulking. Material joining includes fusion welding, resistance welding, solid-state welding, diffusion bonding, brazing (brazing, soldering), pressure welding, friction welding, sintering, and insert casting. Chemical joining includes adhesive bonding, plating, and vapor deposition.

[0095] The "mechanically bonded structure" in this embodiment is a bonded structure formed by a fused deposition modeling method such as a 3D printer, and is not classified as a bonding method that uses mechanical fasteners such as bolts, rivets, etc. According to the inventors' findings, the bonding method according to this embodiment is a bonding method that has the characteristics of both mechanical bonding and material bonding, and therefore the term "mechanically bonded structure" is used in this specification.

[0096] Furthermore, the "mechanically bonded structure" is a nested structure. The "nested structure" here includes a configuration in which parts made of different types of metal materials are combined and bonded together.

[0097] <Comparison of the Technology According to the Present Embodiment with the Prior Art> According to the turbomolecular pump 100 of the present embodiment as described above, the portion that becomes the joint 212 of the plurality of metal materials has a structure that incorporates and joins a portion of the metal materials (an inclusion joining structure), and therefore has the following advantages (merits) compared to the prior art (described later).

[0098] As prior art, in addition to the above-mentioned Patent Document 1, for example, Japanese Patent Application Laid-Open No. 2000-274394, Japanese Patent Application Laid-Open No. 2007-71139, Japanese Patent Application Laid-Open No. 2008-184927, and Japanese Patent Application Laid-Open No. 2005-180265 can be cited.

[0099] Of these, Japanese Patent Application Laid-Open No. 2000-274394 (paragraphs 0008, 0009, etc.) discloses that "As a result, the rotor components can be individually manufactured, for example, by machining," and that "Methods for joining the rotor components include shrink fitting and fastening with bolts. By providing the joining portion with projections and recesses that fit together, the two can be firmly fixed, and positioning during joining is also easy."

[0100] Japanese Patent Application Laid-Open No. 2007-71139 (e.g., 0010) discloses a "composite molecular pump consisting of a low vacuum side pump rotor made of a heat-resistant metal material and a high vacuum side pump rotor made of a light metal or light alloy, which is connected to the low vacuum side pump rotor by casting the end of the low vacuum side pump rotor around it." This method can be said to be a nested structure for the joints of the divided rotor members.

[0101] Japanese Patent Application Laid-Open Publication No. 2008-184927 (e.g., 0015, 0019) discloses that "...the pump comprises a plurality of rotating blades radially arranged on the outer periphery of the rotor body, each attached to the rotor body by a dovetail joint; a fixed blade fixed within the pump case in the axial direction of the rotor body, spaced apart from the rotating blades by a gap; and an insert member sandwiched between the dovetail groove and dovetail joint of the dovetail joint." It also discloses that "by selecting materials for the insert member and dovetail joint as described above, a sufficiently large joining force of the dovetail joint can be ensured even at elevated temperatures." This structure prevents a decrease in joining force due to elevated temperatures during operation by using a dovetail or dovetail joint between the rotor body and the blades, sandwiching a material with a high linear expansion coefficient at the joint, and joining them by shrink fitting.

[0102] Japanese Patent Application Laid-Open No. 2005-180265 (paragraphs 0015, 0043, etc.) discloses that "...reinforcing fibers are filled inside the pump components that make up the vacuum pump," and that "the die-casting method shown in Figure 2b can be used in the exterior material molding process."

[0103] However, when bolting is used, as in the invention disclosed in JP 2000-274394 A, stress concentration areas may occur in the bolt holes. Furthermore, there is a possibility that the bolts may loosen or may not be tightened properly. This also increases the number of parts and the number of assembly steps. Furthermore, adding bolts may cause the rotor's weight distribution to become unbalanced. Furthermore, when shrink fitting is used, it is necessary to consider the stress concentration in the joints when designing, and the number of assembly steps increases.

[0104] Furthermore, when casting, as in the invention disclosed in JP 2007-71139 A, the parts thermally expand during casting, making it difficult to obtain the desired dimensions (expected dimensions, designed dimensions). Furthermore, when dissimilar metals are cast and then contract, gaps are likely to form at the interface due to differences in thermal expansion coefficients. Furthermore, if the melting points of the components are close, the components to be cast may also melt, so combinations of metals with sufficiently different melting points are limited. Furthermore, because the components are heated to high temperatures during casting, the effects of heat treatment during material production are diminished, potentially reducing the strength of the material.

[0105] Furthermore, when combining an inserting member with a dovetail groove or dovetail structure, as in the invention disclosed in JP 2008-184927 A, it is difficult to fit many blades together at once when assembling by shrink fitting. Furthermore, repeating the shrink fitting multiple times increases the number of assembly steps.

[0106] In addition, as in the invention disclosed in JP 2005-180265 A, when high-strength fibers are inserted into the rotor to reinforce it, a die-casting method is used to form the exterior material around the fibers. However, if this method is used for the entire rotor, the fiber material must first be processed into the rotor shape, requiring many steps. Furthermore, if the exterior material is not formed with a uniform thickness, the weight distribution may be unbalanced. Furthermore, when the rotor is manufactured in sections, the methods disclosed in JP 2000-274394 A, JP 2007-71139 A, and JP 2008-184927 A each may be used to join the components, but these methods present the various problems described above.

[0107] In contrast to these conventional techniques, the turbomolecular pump 100 of this embodiment uses a 3D printer to manufacture the rotor 114 as a single unit, eliminating the need to separate and manufacture each part in advance even when combining two or more types of materials (metal materials), and making assembly of parts unnecessary (or easy). Furthermore, the turbomolecular pump 100 of this embodiment also reinforces the joints of dissimilar materials (dissimilar metal materials) using an "inclusive joint structure," which also makes assembly unnecessary (or easy). It also makes it possible to easily reinforce the rotor 114 partially.

[0108] Furthermore, according to the turbomolecular pump 100 of this embodiment, the entire rotor 114 is manufactured as a single unit by 3D printing, which eliminates various problems associated with conventional techniques such as bolting, shrink fitting, casting, etc., when joining parts. In addition, by employing a structure in which multiple metal materials are intertwined as the inclusion joining structure, or a mechanical joining structure, and further employing a nested structure as the mechanical joining structure, parts can be firmly joined without the need for cumbersome assembly work.

[0109] Furthermore, because the encapsulated bonded structure is formed using the 3D printer 280, gaps are unlikely to form at the joint 212 between the rotating turbine impeller 102 (blade portions 102a, 102b, 102c, etc.) and the rotor main body 103a. Therefore, it is possible to firmly bond components formed from different metal materials. Furthermore, because the shaping is performed using the 3D printer 280, even if a metal material that is relatively difficult to process with a blade (e.g., stainless steel or titanium) is used as the first metal material (or the second metal material), the difficulty of processing is less likely to have an effect. Therefore, the rotor impeller 114 can be easily formed regardless of the selected material.

[0110] The "container-bonded structure" is not limited to the structure shown in FIG. 5(a) (first embodiment), and various forms can be considered, such as a hook-shaped structure, a tapered structure, a screw-shaped structure, and a protrusion-shaped structure.

[0111] 5(b) to (e) and 6(a) to (d) show examples of other aspects of the "inclusion coupling structure." In the example of FIG. 5(b) (second embodiment), an I-shaped portion (linear convex portion) 314 that serves as a tenon is formed at the base end of the blade portion 102a. A recess 316 that is shaped to match the I-shaped portion 314 of the blade portion 102a is formed in the rotor main body 103a, and the I-shaped portion 314 and the recess 316 are tightly coupled together without any gaps.

[0112] 5(c) (third embodiment), a T-shaped section 324 is formed at the base end of the blade section 102a. A recess 326 is formed in the rotor main body 103a so as to match the T-shaped section 324 of the blade section 102a, and the T-shaped section 324 and the recess 326 are in close contact and joined together so as not to create a gap.

[0113] 5(d) (fourth embodiment), an L-shaped section 334 having an L-shaped cross section is formed at the base end of the blade section 102a. A recess 336 having a shape that matches the L-shaped section 334 of the blade section 102a is formed in the rotor main body 103a, and the L-shaped section 334 and the recess 336 are in close contact and joined together so as not to create a gap.

[0114] 5(e) (fifth embodiment), a wedge portion 344 having a wedge-shaped cross section is formed at the base end of the blade portion 102a. A recess 346 having a shape that matches the wedge portion 344 of the blade portion 102a is formed in the rotor main body 103a, and the wedge portion 344 and the recess 346 are in close contact and joined together so as not to create a gap.

[0115] 6(a) (sixth embodiment), a dovetail joint 354 having a cross section resembling a dovetail is formed at the base end of the blade portion 102a. A recess 356 having a shape that matches the dovetail joint 354 of the blade portion 102a is formed in the rotor main body 103a, and the dovetail joint 354 and the recess 356 are tightly joined together without any gaps.

[0116] In the example of Fig. 6(b) (seventh embodiment), a toothed portion 364 having a toothed cross section is formed at the base end of the blade portion 102a. A plurality of recesses 366 having a shape that matches the toothed portion 364 of the blade portion 102a are formed in the rotor main body 103a, and the toothed portion 364 and the recesses 366 are in close contact and joined so as not to create gaps. Note that although the portion having a shape in the example of Fig. 6(b) (seventh embodiment) is referred to here as a "toothed portion having a toothed cross section," it may also be referred to as, for example, a "protrusion portion having a cross section with a plurality of protrusions."

[0117] 6(c) (eighth embodiment), a V-shaped portion 374 having a V-shaped cross section is formed at the base end of the blade portion 102a. A recess 376 having a shape that matches the V-shaped portion 374 of the blade portion 102a is formed in the rotor main body 103a, and the V-shaped portion 374 and the recess 376 are in close contact and joined together so as not to create a gap.

[0118] In the example of Fig. 6(d) (ninth embodiment), a thread groove portion 384 having a thread-like cross section is formed at the base end of the blade portion 102a. A recess 386 having a shape that matches the thread groove portion 384 of the blade portion 102a is formed in the rotor main body 103a, and the thread groove portion 384 and the recess 386 are in close contact and coupled so as to leave no gap. Note that the thread groove portion 384 is not limited to being formed in a spiral shape, and may be, for example, one in which a large number of annular protrusions and recesses are formed alternately.

[0119] The structures shown in Figures 5(a)-(e) and 6(a)-(d) can also be referred to as joint structures. In addition to the structures shown in Figures 5(a)-(e) and 6(a)-(d), structures such as a conical protrusion enclosed within a recess can also be used. The combination of the dovetail joint 354 and recess 356 in the example shown in Figure 6(a) can also be referred to as a combination of a dovetail tenon (354) and a dovetail groove (356). Furthermore, the combination of the wedge 344 and recess 346 in the example shown in Figure 5(e) can also be referred to as a combination of a dovetail tenon (344) and a dovetail groove (346).

[0120] It should be noted that various types of "container bonded structures" can be classified, for example, as follows. The "container bonded structures" in the examples of Figures 5(c) to (e) and Figures 6(a), (c), and (d) can be said to be hook-shaped structures. The examples of Figures 5(e) and 6(a) to (d) can be said to be tapered structures. The example of Figure 6(d) can be said to be a screw-shaped structure. The examples of Figures 5(b) to (e) and Figures 6(a) to (d) can be said to be protruding structures. The example of Figure 5(a) can be said to be a flat structure. The classification described here is just an example, and various other classifications are possible.

[0121] <Advantages of using dissimilar materials> As described above, the use of dissimilar materials between the blade portion 102a and the rotor main body (support portion) 103a, between the rotating turbine blade (rotating turbine blade portion) 102 and the rotor main body (cylindrical portion) 103a, between the rotor main body (first cylindrical portion) 103a and the rotor lower cylindrical portion (second cylindrical portion) 103b, etc., provides the following advantages.

[0122] <Aspect in which the first metal material has a lower specific gravity than the second metal material> For example, as shown in FIG. 9( a), if the specific gravity of the metal material (first metal material) of the blade portions 102a, 102b, 102c... is lower than the metal material (second metal material) of the rotor body (support portion) 103a, the stress applied to the base ends of the blade portions 102a, 102b, 102c... (such as the base end 214 in the example of FIG. 5( a)) and their surrounding areas (the area surrounded by ellipse C in FIG. 9( a)) is reduced. As a result, it is possible to further increase the rotation speed of the rotor 114 and increase the allowable temperature during rotation. In this aspect, for example, the first metal material (such as the blade portions 102a, 102b, 102c...) is lower than the second metal material (such as the rotor body (support portion) 103a).

[0123] 9A, the cross sections of the blade portions 102a, 102b, 102c, etc. are distinguished from the cross sections of other portions by the presence or absence of hatching. The "inclusion coupling structure" in FIG. 9A corresponds to the wedge portion 344 in the example of FIG. 5E (fifth embodiment).

[0124] <An embodiment in which the second metal material contained in the portion other than the portion made of the first metal material has higher heat resistance than the first metal material> For example, as shown in Figure 9(a), if a material with a relatively high heat resistance temperature is used in the portion other than the blade portions 102a, 102b, 102c, etc., it becomes possible to perform high-temperature operation with an increased allowable temperature during rotation.

[0125] More specifically, the cylindrical portion (here, the rotor main body 103a) that supports the blade portions 102a, 102b, 102c, etc. may experience stresses higher than those generated inside the blade portions 102a, 102b, 102c, etc. due to centrifugal forces generated during rotation. Furthermore, as a characteristic of metal materials, tensile strength decreases with increasing temperature. Therefore, using a material with a high heat resistance temperature for the cylindrical portion (here, the rotor main body 103a) that supports the blade portions can prevent loosening due to reduced strength and improve the reliability of the joints at higher temperatures. Furthermore, the rotor 114 as a whole can operate (rotate) with high reliability at high temperatures. The term "heat resistance" is used here to refer to the strength of the material's characteristics (strength) at high temperatures.

[0126] 9(a), if the heat resistance of the metal material (second metal material) of the rotor main body (cylindrical portion) 103a is higher than that of the metal material (first metal material) of the blade portions 102a, 102b, 102c, etc., high-temperature operation is possible. As a result, the rotor 114 as a whole can operate (rotate) with high reliability at high temperatures.

[0127] Furthermore, as shown in FIG. 9( b), when the heat resistance of the metal material (second metal material) of the rotor lower cylindrical portion 103b of the rotor 103 is higher than that of the metal material (first metal material) of the rotor main body (cylindrical portion) 103a, high-temperature operation is possible in a situation where the rotor lower cylindrical portion 103b has a higher temperature distribution during rotation than the blade portions 102a, 102b, 102c, etc. As a result, the rotor 114 as a whole can operate (rotate) with high reliability even at high temperatures. Note that, because the gap between the rotor lower cylindrical portion 103b and the fixed portion (non-rotating portion) is relatively narrow, it is desirable to use a material with high heat resistance to prevent deformation during operation at high temperatures.

[0128] 9B, the cross section of the lower cylindrical portion 103b of the rotor is distinguished from the cross sections of other portions by the presence or absence of hatching. The "inclusion coupling structure" in FIG. 9B corresponds to the structure in which the orientation of the wedge portion 344 in the example of FIG. 5D (fourth embodiment) is changed by 90 degrees (upward in the figure).

[0129] <Aspect in which the second metal material has a higher linear expansion coefficient than the first metal material> When the linear expansion coefficient of the metal material of the cylindrical portion (e.g., the rotor 103) is higher than that of the metal material of the portions other than the cylindrical portion (such as the blade portions 102a, 102b, 102c, etc.), as the temperature rises during operation, the joint between the cylindrical portion (e.g., the rotor main body 103a of the rotor 103) and the portions other than the cylindrical portion (such as the blade portions 102a, 102b, 102c, etc.) becomes tight (a state in which the joint is crimped due to the difference in the amount of expansion), making it possible to more reliably prevent the joint between the two from coming loose.

[0130] In addition, in order to obtain the technical effect that the parts that make up the encapsulated bonding structure are less likely to loosen when the rotor 114 becomes hot, it is effective to position the part of the second metal material with a high (large) linear expansion coefficient inside the part of the first metal material.

[0131] <Inventions that can be extracted from each embodiment> The following inventions can be extracted from each of the embodiments described above: (1) A vacuum pump (such as the turbomolecular pump 100) that has a rotor blade (such as the rotor blade 114) that is disposed on a rotor shaft (such as the rotor shaft 113) and rotates together with the rotor shaft, and that exhausts gas (such as exhaust gas or process gas) by exhaust elements (such as the rotary turbine blade 102, the rotor main body 103a, and the rotor lower cylindrical portion 103b) provided on the rotor blade due to the rotation of the rotor shaft, wherein the rotor blade is made of a plurality of metal materials (such as a first metal material and a second metal material), and at least some of the constituent parts (such as the rotary turbine blade 102, the rotor main body 103a, and the rotor lower cylindrical portion 103b) are manufactured by fused deposition modeling means (such as a 3D printer 280), A vacuum pump characterized in that the joints of the plurality of metal materials (joints 212, 312, 322, 332, 342, 352, 362, 372, 382, ​​etc.) have an inclusion structure in which one of the metal materials contains at least a part of the other. (2) The vacuum pump described in (1) above, characterized in that the inclusion structure forms a hook-shaped structure. (3) The vacuum pump described in (1) above, characterized in that the inclusion structure forms a tapered structure. (4) The vacuum pump described in (1) above, characterized in that the inclusion structure forms a screw-shaped structure. (5) The vacuum pump described in (1) above, characterized in that the inclusion structure forms a plurality of protrusion-shaped structures. (6) The vacuum pump according to any one of claims 1 to 5, characterized in that the rotor is composed of blade portions (blade portions 102a, 102b, 102c, etc.) of a turbine impeller portion (rotating turbine impeller 102, etc.) constituting a turbomolecular pump portion (turbomolecular pump mechanism portion 138, etc.) made of a first metallic material (aluminum, etc.), and other portions (such as portions of rotor 114 other than blade portions 102a, 102b, 102c, etc.) including a support portion (rotating body main body 103a, etc.) that supports at least the blade portions and that is made of a second metallic material, and has the inclusion bonded structure at the joint between the blade portions and the support portion, and the first metallic material has a lower specific gravity than the second metallic material.(7) The vacuum pump according to any one of claims 1 to 5, characterized in that the rotor is composed of blade portions (blade portions 102a, 102b, 102c, etc.) of a turbine impeller portion (rotating turbine impeller 102, etc.) constituting a turbomolecular pump portion made of a first metal material (aluminum, etc.), and other portions (such as portions of rotor 114 other than blade portions 102a, 102b, 102c, etc.) including a support portion (rotating body main body 103a, etc.) that supports at least the blade portions and that is made of a second metal material, the vacuum pump having the inclusion bonded structure at the joint between the blade portions and the support portion, and the second metal material having higher heat resistance than the first metal material. (8) The vacuum pump according to any one of claims 1 to 5, characterized in that the rotor is composed of a turbine blade portion (rotating turbine blade 102, etc.) constituting a turbomolecular pump portion made of a first metal material (aluminum, etc.), and a cylindrical portion (lower rotor cylindrical portion 103b, etc.) constituting a thread groove pump portion (thread groove pump mechanism portion, Holweck type exhaust mechanism portion 204, etc.) made of a second metal material, the encapsulated bond structure is formed at the joint between the turbine blade portion and the cylindrical portion, and the second metal material has a higher heat resistance than the first metal material. (9) The vacuum pump according to any one of claims 1 to 5, characterized in that the rotor is composed of a turbine blade portion (rotating turbine blade 102, etc.) constituting a turbomolecular pump portion made of a first metallic material (aluminum, etc.), and a cylindrical portion (rotor lower cylindrical portion 103b, etc.) constituting a thread groove pump portion (thread groove pump mechanism portion, Holweck type exhaust mechanism portion 204, etc.) made of a second metallic material, the vacuum pump has the inclusion bonded structure at the joint between the turbine blade portion and the cylindrical portion, and at the joint, at least a part of the cylindrical portion is arranged inside the turbine blade portion, and the second metallic material has a higher linear expansion coefficient than the first metallic material.(10) A vacuum pump component (e.g., rotor 114) made of a plurality of metal materials (e.g., a first metal material, a second metal material), at least a portion of the constituent parts being manufactured by a fused deposition modeling method (e.g., a 3D printer 280), and characterized in that at the joint (e.g., joint 212) of the plurality of metal materials, one part contains at least a portion of the other part, and has an inclusion bonding structure.

[0132] <Others> The present invention is not limited to the above-described embodiments, and various modifications and combinations of the embodiments are possible without departing from the gist of the present invention.

[0133] For example, it is possible to form one portion (e.g., the rotating turbine blade 102) by fusion deposition modeling (such as a 3D printer) and form the other portion (e.g., the rotating body main body 103a) by means other than fusion deposition modeling (such as a 3D printer) (e.g., a casting means).It is also possible to form one portion (e.g., the rotating turbine blade 102) and a cylindrical portion that supports that portion by fusion deposition modeling (such as a 3D printer), and then cut the cylindrical portion to form the other portion (e.g., the rotating body main body 103a).

[0134] DESCRIPTION OF SYMBOLS 100: Turbo molecular pump 102 (102a, 102b, 102c...): Rotating turbine blade 103: Rotor 103a: Rotor body main body 103b: Rotor lower cylindrical portion 113: Rotor shaft 114: Rotating blade 116: Exhaust element 212, 312, 322, 332, 342, 352, 362, 372, 382: Joint portion 214: Base end portion 216, 316, 326, 336, 346, 356, 366, 376, 386: Recess 218, 220: Lower layer 219, 221: Upper layer 222: Layer 280: 3D printer 284A: First filament 284B: Second filament 286A: First head portion 286B: Second head portion 314: I-shaped portion 324: T-shaped portion 334: L-shaped portion 344: Wedge portion 354: Dovetail portion 364: Tooth portion 374: V-shaped portion 384: Thread groove portion

Claims

1. A vacuum pump having a rotor blade disposed on a rotor shaft and rotating together with the rotor shaft, wherein the rotation of the rotor shaft causes gas to be exhausted by an exhaust element provided on the rotor blade, wherein the rotor blade is made of a plurality of metal materials, at least some of the constituent parts are made by fused deposition modeling, and the part where the plurality of metal materials are joined has an inclusion bonding structure in which one part contains at least a part of the other.

2. The vacuum pump according to claim 1, wherein the inclusion coupling structure forms a hook-shaped structure.

3. The vacuum pump according to claim 1, wherein the inclusion coupling structure forms a tapered structure.

4. The vacuum pump according to claim 1, wherein the inclusion coupling structure forms a screw-like structure.

5. The vacuum pump according to claim 1, wherein the inclusion structure forms a plurality of protrusion structures.

6. A vacuum pump as claimed in any one of claims 1 to 5, characterized in that the rotor is composed of a blade portion of a turbine impeller constituting a turbomolecular pump section made of a first metal material, and other portions including a support portion made of a second metal material that supports at least the blade portion, and has the inclusion bonding structure at the joint between the blade portion and the support portion, and the first metal material has a lower specific gravity than the second metal material.

7. A vacuum pump as claimed in any one of claims 1 to 5, characterized in that the rotor is composed of a blade portion of a turbine impeller constituting a turbomolecular pump section made of a first metallic material, and other portions including a support portion made of a second metallic material that supports at least the blade portion, the joint portion between the blade portion and the support portion has the inclusion bonding structure, and the second metallic material has higher heat resistance than the first metallic material.

8. A vacuum pump as claimed in any one of claims 1 to 5, characterized in that the rotor is composed of a turbine blade portion constituting a turbomolecular pump portion made of a first metallic material and a cylindrical portion constituting a thread groove pump portion made of a second metallic material, the joint between the turbine blade portion and the cylindrical portion has the inclusion bonding structure, and the second metallic material has higher heat resistance than the first metallic material.

9. A vacuum pump as claimed in any one of claims 1 to 5, characterized in that the rotor is composed of a turbine blade portion constituting a turbomolecular pump portion made of a first metallic material and a cylindrical portion constituting a threaded pump portion made of a second metallic material, the rotor has the inclusion bonding structure at the joint between the turbine blade portion and the cylindrical portion, and at the joint, at least a part of the cylindrical portion is arranged inside the turbine blade portion, and the second metallic material has a higher linear expansion coefficient than the first metallic material.

10. A vacuum pump component made of multiple metal materials, at least some of the components being manufactured by fused deposition modeling, characterized in that the joints between the multiple metal materials have an inclusion bonded structure in which one part contains at least a part of the other.

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