Vacuum pump and hermetic connector

Abstract

To achieve compact size and high performance while reducing manufacturing cost of a hermetic connector.SOLUTION: A vacuum pump (100) comprises a hermetic connector (10). The hermetic connector (10) comprises pins (11 and 12) connected electrically, a connector base part (13) surrounding the pins (11 and 12), and a sealing part (14) for sealing a gap between the pins (11 and 12) and the connector base part (13). The sealing part (14) is made of a resin material having insulation performance.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a vacuum pump and a hermetic connector for use in a vacuum pump. [Background technology]

[0002] As a conventional technique in this technical field, for example, a vacuum pump described in Patent Document 1 is equipped with a hermetic connector having a horizontal structure. The hermetic connector applied to the vacuum pump is required to have high airtightness and high heat resistance. For this reason, the gap between the connector base and the pin of the hermetic connector is generally sealed with a glass material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6912196 Summary of the Invention [Problem to be solved by the invention]

[0004] When manufacturing the above-mentioned conventional hermetic connector, there is a problem that the manufacturing cost is high because the process of sealing with a glass material is special. In addition, the hermetic connector used in a vacuum pump is required to be small, but a large number of pins are required and a high level of leak rate performance is required. In particular, in the case of a vacuum pump, if the atmosphere enters the inside through the hermetic connector, the pump performance may be deteriorated. Therefore, there is a demand to manufacture a small, high-performance hermetic connector with a predetermined leak rate performance at low cost.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to realize a hermetic connector that is small in size and has high performance while reducing the manufacturing costs. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, a first aspect of the present invention is a vacuum pump equipped with a hermetic connector, the hermetic connector having electrically connected pins, a connector base portion surrounding the pins, and a sealing portion sealing between the pins and the connector base portion, the sealing portion being made of an insulating resin material.

[0007] In the above configuration, the sealing portion includes a first sealing portion covering an outer surface of the pin and a second sealing portion sealing between the first sealing portion and the connector base portion, and the connector base portion is made of a metal material, the first sealing portion is made of a first resin material, and the second sealing portion is made of a second resin material.

[0008] In the above configuration, the linear expansion coefficient of the first resin material is equal to or greater than the linear expansion coefficient of the second resin material.

[0009] In the above configuration, the hermetic connector is characterized in that it further has a labyrinth structure between the pin and the sealing portion for suppressing the passage of gas.

[0010] In the above configuration, the labyrinth structure includes a convex portion and / or a concave portion provided on an outer surface of the pin.

[0011] In order to achieve the above object, a second aspect of the present invention is a hermetic connector for use in a vacuum pump, comprising electrically connected pins, a connector base portion surrounding the pins, and a sealing portion sealing between the pins and the connector base portion, the sealing portion being made of an insulating resin material. Effect of the Invention

[0012] According to the present invention, it is possible to realize a hermetic connector that is small in size and has high performance while suppressing the manufacturing cost of the hermetic connector. Note that problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0013] [Figure 1] 1 is a vertical sectional view of a turbomolecular pump according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a circuit diagram of an amplifier circuit of the turbomolecular pump shown in FIG. [Diagram 3] 6 is a time chart showing the control of the amplifier control circuit when a current command value is larger than a detection value. [Figure 4] 6 is a time chart showing the control of the amplifier control circuit when a current command value is smaller than a detection value. [Diagram 5] FIG. 2A is a front view of the hermetic connector according to the embodiment, and FIG. [Figure 6] 6A is a front view of a hermetic connector according to a first modified example, and FIG. 6B is a sectional view taken along the line VIb-VIb. [Figure 7] 13A is a longitudinal sectional view of a hermetic connector according to Modification 2, and FIG. [Figure 8] 1(a) to 1(c) are diagrams showing variations of the labyrinth structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vacuum pump according to the present invention will now be described with reference to the drawings, taking a turbomolecular pump as an example.

[0015] A longitudinal cross-sectional view of this turbomolecular pump 100 is shown in Fig. 1. In Fig. 1, the turbomolecular pump 100 has an intake port 101 formed at the upper end of a cylindrical outer tube 127 that is an exterior body. Inside the outer tube 127, a rotor 103 is provided, the rotor 103 having a plurality of rotors 102 (102a, 102b, 102c, ...) that are turbine blades for sucking in and exhausting gas, formed radially on the periphery and in multiple stages. A rotor shaft 113 is attached to the center of the rotor 103, and the rotor shaft 113 is supported in the air and positionally controlled by, for example, a five-axis controlled magnetic bearing. The rotor 103 is generally made of a metal such as aluminum, an aluminum alloy, or stainless steel.

[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 of the upper radial electromagnets 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 the change in inductance of the conductive windings that changes according to 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 electromagnet 104. Such adjustment is performed independently in the X-axis direction and the Y-axis direction. The lower radial electromagnet 105 and the lower radial sensor 108 are arranged in the same manner as the upper radial electromagnet 104 and the upper radial sensor 107, and adjust the lower radial position of the rotor shaft 113 in the same manner as the upper radial position.

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

[0020] In the control device 200, a compensation circuit having, for example, a PID adjustment function generates an excitation control command signal 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 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 force that the axial electromagnets 106A, 106B exert on the metal disk 111, magnetically levitating the rotor shaft 113 in the axial direction and holding it in a non-contact manner in space. The amplifier circuit 150 that controls the excitation of the upper radial electromagnets 104, the lower radial electromagnets 105, and the axial electromagnets 106A, 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. Also, motor 121 incorporates a rotation speed sensor such as a Hall element, resolver, or encoder (not shown), and the rotation speed of rotor shaft 113 is detected by a detection signal from this rotation speed sensor.

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

[0024] A plurality of fixed blades 123 (123a, 123b, 123c...) are arranged at small gaps from the rotor blades 102 (102a, 102b, 102c...). The multiple stages of rotor blades 102 and the multiple stages of fixed blades 123 form a turbo pump section. The rotor blades 102 (102a, 102b, 102c...) are formed at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113 in order to transport exhaust gas molecules downward by collision. The fixed blades 123 (123a, 123b, 123c...) are made of metal such as aluminum, iron, stainless steel, copper, or an alloy containing these metals as components.

[0025] Similarly, the fixed blades 123 are formed at an inclination at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113, and are arranged alternately with the stages of the rotor blades 102 toward the inside of the outer cylinder 127. The outer peripheral ends of the fixed blades 123 are supported in a state where they are inserted between a plurality of stacked stages of fixed blade spacers 125 (125a, 125b, 125c, etc.).

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

[0027] Furthermore, depending on the application of the turbo molecular pump 100, a threaded spacer 131 functioning as a thread groove pump section is disposed between the lower part of the fixed vane spacer 125 and the base section 129. The threaded spacer 131 is a cylindrical member made of metal such as aluminum, copper, stainless steel, iron, or an alloy containing these metals, and has a plurality of helical thread grooves 131a engraved on its inner peripheral surface. The helical direction of the thread groove 131a is the direction in which, when exhaust gas molecules move in the rotation direction of the rotor 103, the molecules are transported toward the exhaust port 133. A cylindrical section 102d hangs down from the lowest part of the rotor 103, which is connected to the rotor vanes 102 (102a, 102b, 102c, etc.). The outer peripheral surface of this cylindrical section 102d is cylindrical and protrudes toward the inner peripheral surface of the threaded spacer 131, and is adjacent to the inner peripheral surface of the threaded spacer 131 with a predetermined gap therebetween. The exhaust gas transferred to the thread groove 131a by the rotor 102 and the fixed blade 123 is sent to the base portion 129 while being guided by the thread groove 131a.

[0028] The base portion 129 is a disk-shaped member that constitutes the base of the turbomolecular pump 100, and is generally made of a metal such as iron, aluminum, or stainless steel. The base portion 129 physically holds the turbomolecular pump 100 and also functions as a heat conduction path, so it is desirable to use a metal that has rigidity and high thermal conductivity, such as iron, aluminum, or copper. In addition, a hermetic connector 10 is provided on the side of the base portion 129. The control device 200 is connected via this hermetic connector 10. The hermetic connector 10 will be described in detail later.

[0029] In this configuration, when the rotor 102 is rotated together with the rotor shaft 113 by the motor 121, the exhaust gas is sucked from the chamber through the intake port 101 by the action of the rotor 102 and the fixed blade 123. The rotation speed of the rotor 102 is usually 20,000 rpm to 90,000 rpm, and the peripheral speed at the tip of the rotor 102 reaches 200 m / s to 400 m / s. The exhaust gas sucked through the intake port 101 passes between the rotor 102 and the fixed blade 123 and is transferred to the base part 129. At this time, the temperature of the rotor 102 rises due to frictional heat generated when the exhaust gas comes into contact with the rotor 102 and conduction of heat generated by the motor 121, and the like, but this heat is transferred to the fixed blade 123 side by radiation or conduction by gas molecules of the exhaust gas, and the like.

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

[0031] In the above description, the threaded spacer 131 is disposed on the outer periphery of the cylindrical portion 102d of the rotor 103, and the thread groove 131a is formed on the inner periphery of the threaded spacer 131. However, there are also cases where the thread groove is formed on the outer periphery of the cylindrical portion 102d, and a spacer having a cylindrical inner periphery is disposed around the outer periphery of the cylindrical portion 102d.

[0032] Depending on the application of the turbomolecular pump 100, in order 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., the electrical equipment section may be covered all around with a stator column 122, and the inside of this stator column 122 may be kept at a predetermined pressure by a purge gas.

[0033] In this case, a pipe (not shown) is provided in the base portion 129, and the purge gas is introduced through this pipe. The introduced purge gas is sent to the 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 stator column 122 and the inner cylindrical portion of the rotor blades 102. As shown in FIG. 1, the stator column 122 is erected at the center position of the base portion 129. In this embodiment, the base portion 129 is provided with a water-cooled pipe 149 as a cooling means. Cooling water is supplied to this water-cooled pipe 149, so that the base portion 129 and the stator column 122 are kept at an appropriate temperature.

[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 identified as a model. In order to store these control parameters, the turbomolecular pump 100 has an electronic circuit section 141 in its main body. The electronic circuit section 141 is composed of a semiconductor memory such as an EEPROM, electronic components such as semiconductor elements for accessing the memory, and a substrate 143 for mounting these components. The electronic circuit section 141 is housed below a rotational speed sensor (not shown) near the center of a base section 129 that constitutes the lower part of the turbomolecular pump 100, and is closed by an airtight bottom cover 145.

[0035] In the semiconductor manufacturing process, some process gases introduced into the chamber have the property of becoming solid when their pressure exceeds a predetermined value or their temperature falls below a predetermined value. Inside the turbo molecular pump 100, the pressure of the exhaust gas is lowest at the intake port 101 and highest at the exhaust port 133. If the pressure of the process gas becomes higher than a predetermined value or the temperature falls below a predetermined value while the process gas is being transferred from the intake port 101 to the exhaust port 133, the process gas becomes solid and adheres to and accumulates inside the turbo molecular pump 100.

[0036] For example, when SiCl4 is used as the process gas in an Al etching device, low vacuum (760[torr]~10 -2 It can be seen from the vapor pressure curve that at a vapor pressure of 100 MPa (100 [torr]) and low temperature (approximately 20 [°C]), solid products (e.g., AlCl3) precipitate and adhere to and accumulate inside the turbomolecular pump 100. As a result, when precipitates of the process gas accumulate inside the turbomolecular pump 100, the deposits narrow the pump flow path, causing a decrease in the performance of the turbomolecular pump 100. The above-mentioned products are prone to solidification and adhesion in high-pressure areas near the exhaust port 133 and near the threaded spacer 131.

[0037] Therefore, in order to solve this problem, in the past, a heater (not shown) or a circular water-cooled tube 149 was wrapped around the outer periphery of the base portion 129, and a temperature sensor (e.g., a thermistor) (not shown) was embedded in the base portion 129, and the heating of the heater and the cooling by the water-cooled tube 149 were controlled based on the signal from this temperature sensor to keep the temperature of the base portion 129 at a constant high temperature (set temperature) (hereinafter referred to as TMS; Temperature Management System).

[0038] Next, regarding the turbo molecular pump 100 configured as described above, 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 will be described. A circuit diagram of this amplifier circuit 150 is shown in FIG.

[0039] 2, one end of an electromagnet winding 151 constituting the upper radial electromagnet 104 etc. is connected to a positive electrode 171a of a power source 171 via a transistor 161, and the other end is connected to a negative electrode 171b of the power source 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 cathode terminal 161a of the diode 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 cathode terminal 162a of the diode connected to the current detection circuit 181, and an anode terminal 162b connected to the negative electrode 171b.

[0041] On the other hand, the current regeneration 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 regeneration 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 detection circuit 181. The current detection circuit 181 is composed of, for example, a Hall sensor type current sensor or an electric resistance element.

[0042] The amplifier circuit 150 configured as above corresponds to one electromagnet. Therefore, when the magnetic bearing is controlled by 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) of the control device 200, and this amplifier control circuit 191 switches the transistors 161 and 162 on / off.

[0044] The amplifier control circuit 191 is adapted to compare 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. Then, based on the result of this comparison, the magnitude of the pulse width (pulse width times Tp1, Tp2) to be generated within a control cycle Ts, which is one period of PWM control, is determined. As a result, gate drive signals 191a, 191b having this pulse width are output from the amplifier control circuit 191 to the gate terminals of the transistors 161, 162.

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

[0046] In this configuration, when both transistors 161, 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] Moreover, when one of the transistors 161, 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, the 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, 162 in this manner, high-frequency noise such as harmonics generated in the turbo molecular 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 of the transistors 161 and 162 are turned on for a time period corresponding to the pulse width time Tp1 only once in 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, when the detected current value is larger than the current command value, both of the transistors 161 and 162 are turned off for a time period corresponding to the 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 pole 171b to the positive pole 171a via the 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] <Hermetic connector structure> Next, a detailed description will be given of the structure of the hermetic connector 10 used in the turbo molecular pump 100. Figure 5(a) is a front view of the hermetic connector 10. Figure 5(b) is a cross-sectional view taken along line Vb-Vb of Figure 5(a).

[0052] As shown in Figures 5(a) and (b), the hermetic connector 10 of this embodiment has a plurality of electrically connected small diameter pins 11 and large diameter pins 12, a connector base portion 13 in the form of a horizontally long rectangular frame that surrounds the multiple pins 11, 12, and a sealing portion 14 that seals between the multiple pins 11, 12 and the connector base portion 13.

[0053] In this embodiment, the small diameter pin 11 and the large diameter pin 12 are each formed in a long and thin cylindrical shape, but the shape is not limited thereto. For example, the pins 11 and 12 may be formed in a cylindrical shape having a step formed by arranging cylinders of different diameters coaxially and integrating them, or may be formed in a prismatic shape instead of a cylindrical shape.

[0054] The connector base portion 13 is made of a metal material such as stainless steel. The connector base portion 13 has a horizontally long opening 13a in the center, and holes 18 for bolting to the base portion 129 of the turbo molecular pump 100 are provided at the four corners. The aspect ratio of the connector base portion 13 is, for example, about 1:1.5 to 1:2. Although the connector base portion 13 is formed in a plate shape, the shape is not important. Connector base portions of any shape can be used.

[0055] The sealing portion 14 is made of a resin material having insulating properties. Examples of the resin material that can be used include polyamide / nylon (PA), polyphenylene ether (PPE), polyphenylene sulfide (PPS), and polybutylene terephthalate (PBT). As shown by the diagonal lines in FIG. 5(a), the sealing portion 14 is filled between the connector base portion 13 and the multiple pins 11 and 12, and the connector base portion 13 and the pins 11 and 12 are integrally molded through the sealing portion 14. For example, the pins 11 and 12 may be insert-molded into the sealing portion 14.

[0056] Next, the effects of this embodiment configured as above will be described.

[0057] Since the sealing portion 14 is made of an insulating resin material, the manufacturing process is simpler than in the conventional structure in which glass material is filled, and it is possible to reduce the manufacturing cost of the hermetic connector 10. Furthermore, the hermetic connector 10 used in the turbo molecular pump 100 requires many wirings such as power lines for the motor and electromagnets, sensors, etc., and therefore requires a large number of pins 11 and 12, and a high level of leak rate performance (sealing performance) is required, but in this embodiment, the connector base portion 13 and the pins 11 and 12 are integrally molded by the sealing portion 14 made of a resin material, so that a high level of leak rate performance can be realized.

[0058] Moreover, because the connector base portion 13 is made of a metal material, the gap between the connector base portion 13 and the base portion 129 of the turbomolecular pump 100 can be reliably sealed by an O-ring. Therefore, the hermetic connector 10 according to this embodiment is suitable for the turbomolecular pump 100. Furthermore, because the connector base portion 13 has a horizontally elongated configuration, the axial (height) dimension of the turbomolecular pump 100 can be made compact.

[0059] Thus, according to this embodiment, a small, high-precision, and high-quality hermetic connector 10 with a low leak rate can be realized at low cost. Furthermore, by incorporating the high-performance hermetic connector 10 into the turbomolecular pump 100, it is possible to prevent the exhaust performance of the turbomolecular pump 100 from deteriorating.

[0060] (Variation 1) Next, a description will be given of the structure of the hermetic connector 20 according to the modified example 1. Fig. 6(a) is a front view of the hermetic connector 20. Fig. 6(b) is a cross-sectional view taken along line VIb-VIb of Fig. 6(a).

[0061] As shown in Figures 6(a) and (b), the hermetic connector 20 of variant example 1 has a plurality of small diameter pins 21 and large diameter pins 22 that are electrically connected, a circular frame-shaped connector base portion 23 that surrounds the plurality of pins 21, 22, and a first sealing portion 25 and a second sealing portion 26 that seal between the plurality of pins 21, 22 and the connector base portion 23.

[0062] The connector base portion 23 is made of a metal material such as stainless steel, etc. The connector base portion 23 has a circular opening 23a in the center, and holes 28 for fastening to the base portion 129 of the turbo molecular pump 100 with bolts are provided at the four corners.

[0063] The first sealing portion 25 covers the outer surfaces (outer peripheral surfaces) of the pins 21, 22. The first sealing portion 25 is formed of a cylinder that closely fits the outer shapes of the pins 21, 22. The second sealing portion 26 seals between the first sealing portion 25 and the connector base portion 23. That is, the second sealing portion 26 seals between the multiple pins 21, 22 covered with the first sealing portion 25 and the connector base portion 23.

[0064] Both the first sealing portion 25 and the second sealing portion 26 are made of an insulating resin material. Examples of the resin material that can be used include polyamide / nylon (PA), polyphenylene ether (PPE), polyphenylene sulfide (PPS), and polybutylene terephthalate (PBT). However, the linear expansion coefficient α1 of the resin material (first resin material) of the first sealing portion 25 is equal to or greater than the linear expansion coefficient α2 of the resin material (second resin material) of the second sealing portion 26 (α1≧α2).

[0065] The hermetic connector 20 according to the first modification provides the same effects as the hermetic connector 10 according to the embodiment described above. In addition, since the linear expansion coefficient α1 of the first sealing portion 25 is equal to or greater than the linear expansion coefficient α2 of the second sealing portion 26, the hermetic connector can maintain hermeticity even if a difference in thermal deformation occurs between the connector base portion 23 made of a metal material and the first sealing portion 25 and the second sealing portion 26 made of a resin material. In particular, during operation of the turbo molecular pump 100, the ambient temperature of the hermetic connector 20 rises, so that the difference in thermal deformation between the connector base portion 23 and the first sealing portion 25 and the second sealing portion 26 becomes significant. However, by using two types of resin materials with different linear expansion coefficients, it is possible to reduce the difference in thermal deformation described above, and further, since the linear expansion coefficients satisfy the relationship α1≧α2, it is possible to prevent gaps from occurring around the pins 21 and 22.

[0066] Here, in the first modification, the first sealing portion 25 and the second sealing portion 26 may be made of the same resin material. In this case, the first sealing portion 25 and the second sealing portion 26 take the place of the sealing portion 14 according to the above-described embodiment. In other words, the first sealing portion 25 and the second sealing portion 26 are manufactured as separate members, and are finally integrated together to function as the sealing portion 14. Even with this configuration, it is possible to achieve the same effects as those of the above-described embodiment.

[0067] (Variation 2) Next, the structure of the hermetic connector 30 according to the modified example 2 will be described. The hermetic connector 30 according to the modified example 2 has the same basic structure as the hermetic connector 10 shown in Figures 5(a) and (b), but differs in that it has a labyrinth structure 31 described below. Therefore, the same components of the hermetic connector 30 as those of the hermetic connector 10 will be denoted by the same reference numerals and descriptions thereof will be omitted.

[0068] FIG. 7(a) is a vertical cross-sectional view of a hermetic connector 30 according to the second modification. FIG. 7(b) is an enlarged view of part A in FIG. 7(a). In FIG. 7(a), the small-diameter pin 11 is omitted. As shown in FIGS. 7(a) and 7(b), the hermetic connector 30 according to the second modification has a labyrinth structure 31. The labyrinth structure 31 is composed of a protrusion 32 provided on the large-diameter pin 12 and a recess 33 provided on the sealing portion 14. More specifically, the large-diameter pin 12 has a plurality of protrusions 35 protruding in the radial direction on its outer surface. The plurality of protrusions 35 are provided at intervals along the axial direction of the large-diameter pin 12. Each protrusion 35 is made of a disk shape (flange) protruding from the outer circumferential surface of the large-diameter pin 12.

[0069] On the other hand, the sealing portion 14 is made of a resin material filled between the connector base portion 13 and the large diameter pin 12, and therefore a recess 36 is formed following the shape of the protrusion 35. In the normal state, the protrusion 35 and the recess 36 are in close contact with each other, ensuring sealing. The small diameter pin 11 may also be provided with a labyrinth structure 31.

[0070] During operation of the turbomolecular pump 100, the ambient temperature of the hermetic connector 10 becomes high, and a gap may occur between the large diameter pin 12 and the sealing portion 14 due to the difference in linear expansion coefficient. However, in the second modification, the large diameter pin 12 has a labyrinth structure 31, which makes it possible to prevent air from passing through the gap between the large diameter pin 12 and the sealing portion 14. This makes it possible to prevent a decrease in the leak rate performance of the hermetic connector 10, and to maintain good exhaust performance of the turbomolecular pump 100. Another advantage is that the labyrinth structure can prevent the large diameter pin 12 from being pulled out.

[0071] Next, variations of the labyrinth structure will be described. Figures 8(a), (b), and (c) are diagrams showing variations of the labyrinth structure.

[0072] 8(a) has a convex portion 42 bent like a key. Therefore, a concave portion 43 formed in the sealing portion 14 also has a bent shape following the convex portion 42. Even with this configuration, it is possible to prevent air from passing through the gap between the large diameter pin 12 and the sealing portion 14.

[0073] 8(b) is composed of uneven portions 52 formed on the surface of large pin 12 by knurling, sandblasting, or the like, and uneven portions 53 formed to match uneven portions 52. Even with this configuration, it is possible to prevent air from passing through the gap between large pin 12 and sealing portion 14.

[0074] 8(c) is composed of a recess 62 formed in the large pin 12 and a protrusion 63 formed in the sealing portion 14 so as to match this recess 62. Even with this configuration, it is possible to prevent air from passing through the gap between the large pin 12 and the sealing portion 14.

[0075] In this way, by providing a labyrinth structure between the large pin 12 and the sealing portion 14, even if a gap occurs between the large pin 12 and the sealing portion 14, it is possible to prevent gas from easily passing through this gap. In other words, any structure that can make it difficult for gas to pass through the gap between the large pin 12 and the sealing portion 14 can be used as the labyrinth structure of the present invention.

[0076] 7 and 8, the sealing portion 14 made of a resin material is exemplified, but the labyrinth structures 31, 41, 51, and 61 can also be used for sealing portions made of conventional glass materials. In other words, the labyrinth structure can be applied between the pin and the sealing portion of any hermetic connector. By providing the labyrinth structure, even if a gap occurs between the pin and the sealing portion, it is possible to prevent gas from passing through the gap, preventing a decrease in the leak rate performance of the hermetic connector 10 and further preventing a decrease in the exhaust performance of the turbo molecular pump.

[0077] In the present invention, the gas passing through the hermetic connector 10 is determined by the relationship between the internal pressure and the external pressure of the turbomolecular pump 100. If the internal pressure is higher than the external pressure, there is a possibility that the exhaust gas present in the turbomolecular pump 100 passes from the hermetic connector 10 to the outside. In this case, the gas passing through the hermetic connector 10 is the exhaust gas present in the turbomolecular pump 100. If the internal pressure is lower than the external pressure, the external gas (such as the atmosphere) becomes the gas passing through the hermetic connector 10. And, regardless of the relationship between the internal pressure and the external pressure, the labyrinth structures 31, 41, 51, and 61 of the hermetic connector 10 can suppress the passage of the gas.

[0078] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the present invention, and all technical matters included in the technical ideas described in the claims are the subject of the present invention. The above-described embodiment shows a preferred example, but a person skilled in the art can realize various alternatives, modifications, variations, combinations, or improvements from the contents disclosed in this specification, and these are included in the technical scope described in the attached claims.

[0079] For example, the shape of the connector base part of the hermetic connector is not limited to the horizontally long rectangular frame shape or the circular frame shape described above. Any shape of the connector base part can be used. Furthermore, the shape of the connector base part may be a box shape instead of a frame shape. [Explanation of symbols]

[0080] 10,20,30 Hermetic Connector 11,21 Small diameter pin (pin) 12,22 Large diameter pin (pin) 13,23 Connector base 13a,23a opening 14 Sealing part 18,28 hole 25 First sealing part 26 Second sealing part 31,41,51,61 Labyrinth structure 32,42,62 Convex 33,43,63 Recess 52,53 Uneven part 100 Turbo molecular pump (vacuum pump)

Claims

1. A vacuum pump having a hermetic connector, The hermetic connector comprises: A pin electrically connected thereto; a connector base portion surrounding the pin; a sealing portion that seals between the pin and the connector base portion, The sealing portion is made of an insulating resin material. A vacuum pump characterized by:

2. 2. The vacuum pump according to claim 1, The sealing portion is A first sealing portion covering an outer surface of the pin; a second sealing portion that seals between the first sealing portion and the connector base portion, the connector base portion is made of a metal material, the first sealing portion is made of a first resin material, and the second sealing portion is made of a second resin material; A vacuum pump characterized by:

3. 3. The vacuum pump according to claim 2, The linear expansion coefficient of the first resin material is equal to or greater than the linear expansion coefficient of the second resin material. A vacuum pump characterized by:

4. 2. The vacuum pump according to claim 1, The hermetic connector comprises: Further, a labyrinth structure is provided between the pin and the sealing portion to suppress the passage of gas. A vacuum pump characterized by:

5. 5. The vacuum pump according to claim 4, The labyrinth structure is The pin includes a protrusion and / or a recess provided on an outer surface thereof. A vacuum pump characterized by:

6. A hermetic connector for use in a vacuum pump, comprising: A pin electrically connected thereto; a connector base portion surrounding the pin; a sealing portion that seals between the pin and the connector base portion, The sealing portion is made of an insulating resin material. A hermetic connector comprising:

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