JP4671624B2 - Vacuum pump - Google Patents

Description

  The present invention relates to a vacuum pump that performs evacuation processing of a vacuum device used in, for example, a surface analysis device, a fine processing device, or the like.

For example, vacuum devices that perform evacuation using a vacuum pump and keep the inside in a vacuum include a chamber for a semiconductor manufacturing device, a measurement chamber of an electron microscope, a surface analysis device, a fine processing device, and the like.
Among various vacuum pumps, a turbo molecular pump is often used to realize a high vacuum environment.
The turbo molecular pump is configured such that the rotor rotates at high speed inside a casing having an intake port and an exhaust port. On the inner peripheral surface of the casing, fixed blades are arranged in multiple stages, while on the rotor, rotary blades are arranged radially and in multiple stages. When the rotor rotates at high speed, gas is sucked from the intake port and discharged from the exhaust port by the action of the rotary blade and the fixed blade.

Since the turbo molecular pump performs exhaust processing by rotating the turbine at a high speed, the turbo molecular pump may be heated by a collision heat of gas molecules or heat generated from a motor to be in a high temperature state.
And there exists a possibility of causing trouble in the vacuum apparatus side by the influence of the radiant heat of this vacuum pump.
For example, when a surface analysis device or a microfabrication device is heated by the radiant heat of a vacuum pump, there is a risk that problems such as an error in measurement accuracy and processing accuracy increase. For this reason, it has been difficult to realize more precise processing and more accurate measurement in such an apparatus.
Therefore, in order to reduce the influence of the radiant heat of the vacuum pump, including the following patent documents, techniques for suppressing the heat propagation (conduction) from the vacuum pump and preventing overheating on the vacuum device side have been proposed. Yes.

JP 2002-227765 A

  In Patent Document 1, a vacuum pump and a vacuum device are joined via a member (piping) having a high thermal conductivity, and this member is cooled using a cooling method such as water cooling or air cooling, thereby obtaining a vacuum device. A technique for suppressing the propagation of heat is disclosed.

However, when taking measures against heat as proposed in Patent Document 1, not only a dedicated cooling pipe or cooling system is required, but also a space for arranging these members must be secured. Don't be.
Then, an object of this invention is to provide the vacuum pump which can reduce efficiently the radiant heat of the vacuum pump which propagates to the vacuum apparatus side with a simple structure.

In the first aspect of the present invention, a casing in which an air inlet and an air outlet are formed, and a gas transfer mechanism that is provided in the casing and transfers gas sucked from a vacuum apparatus through the air inlet to the air outlet. The emissivity of the surface facing the gas transfer mechanism is larger than the surface facing the vacuum device, arranged upstream from the gas transfer mechanism, and absorbs heat from the gas transfer mechanism to the vacuum device. The object is achieved by including a heat shield plate for reducing the radiated heat and a fixing means for fixing the heat shield plate.

The heat shield plate according to the first aspect of the invention has a surface treatment with a low emissivity on, for example, a surface facing the vacuum device (a surface facing the upstream direction when viewed from the flow of gas exhausted from the vacuum device). It is preferable that In this case, the surface treatment is preferably, for example, an electropolishing treatment, a gold plating treatment, an aluminum plating treatment or the like so that the emissivity is 0.1 or less.
The heat shield plate of the invention according to claim 1 is, for example, a surface facing the gas transfer mechanism (a surface facing the downstream direction when viewed from the flow of gas exhausted from the vacuum apparatus, or the direction of the exhaust port of the vacuum pump) It is preferable that a surface treatment having a high emissivity is applied to the surface facing the surface. In this case, the surface treatment is preferably, for example, an alumite coating treatment or a ceramic coating treatment such that the emissivity is 0.8 or more.

The fixing means according to the first aspect of the present invention is preferably a member formed of a member having high thermal conductivity, for example. Moreover, it is preferable that this fixing means is integrally formed with the heat shield plate, for example.
The heat shield plate according to the first aspect of the present invention is preferably disposed, for example, in the vicinity of the gas transfer mechanism.

According to a second aspect of the present invention, a casing having an air inlet and an air outlet, a gas transfer mechanism that is provided in the casing and transfers gas sucked from a vacuum apparatus through the air inlet to the air outlet. A heat shield plate disposed upstream of the gas transfer mechanism and having a greater emissivity of a surface facing the gas transfer mechanism than a surface facing the vacuum device, and a fixing means for fixing the heat shield plate And the gas transfer mechanism has a rotor part composed of a rotating shaft and a rotor fixed to the rotating shaft, and rotor blades arranged radially from the outer peripheral surface of the rotor part, The heat shield plate achieves the object by having a region projected on the gas transfer mechanism side substantially equal to a region facing the air inlet of the rotor portion.
In the invention according to claim 2 , for example, the heat shield plate is arranged so that the region where the rotor blades are projected on the intake port side and the region where the heat shield plate is projected on the intake port side do not overlap. It is preferable. That is, the heat shield plate is disposed so that, for example, an area where the heat shield plate is projected on the inlet side and an area where the inlet side surface area of the rotor portion is projected on the inlet side overlap. Preferably it is.

In the invention of claim 3, in the invention of claim 2 , the rotor blade located on the most upstream side is formed such that the emissivity of the surface facing the vacuum device is smaller than the emissivity of the other surfaces. Yes.
In the invention according to claim 3, it is preferable that the rotor blade located on the most upstream side is subjected to a surface treatment with a low emissivity, for example, in a region facing the vacuum device. In this case, the surface treatment with a low emissivity is preferably, for example, an electrolytic polishing treatment, a gold plating treatment, an aluminum plating treatment or the like so that the emissivity is 0.1 or less.

According to a fourth aspect of the invention, there is provided the cooling mechanism according to any one of the first to third aspects, wherein the cooling plate is cooled.
The cooling mechanism in the invention of claim 4 preferably uses, for example, a water cooling (liquid cooling) system in which heat is absorbed by a coolant that is a heat medium flowing in the cooling pipe.

The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the heat shield plate has a concave curved surface on a surface facing the gas transfer mechanism. Is formed.
The concavely curved surface in the invention described in claim 5 is preferably, for example, a parabolic curved surface in which the rotation axis of the vacuum pump is an axis of symmetry and the focal point is provided downstream from the upper surface of the rotor portion.
The concavely curved surface in the invention of claim 5 is preferably provided in multiple stages, for example.

  According to the present invention, the amount of heat radiated from a vacuum pump and propagated to a vacuum device can be reduced.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. In this embodiment, a turbo molecular pump is used as an example of a vacuum pump.
(First embodiment)
FIG. 1 is a diagram showing a schematic configuration of a turbo molecular pump 1 having a radiant heat reduction structure according to the first embodiment. 1 shows a cross-sectional view of the turbo molecular pump 1 in the axial direction.
FIG. 1 also shows a part of the vacuum chamber 30 connected to the turbo molecular pump 1.
Here, the vacuum chamber 30 connected to the turbo molecular pump 1 will be described.
The vacuum chamber 30 forms, for example, a vacuum device used as a chamber of a surface analysis device or a fine processing device.
The vacuum chamber 30 is a vacuum vessel that includes a vacuum chamber wall 31 and has a connection port with the turbo molecular pump 1.

Below, the structure of the turbo-molecular pump 1 is demonstrated.
The turbo molecular pump 1 is a vacuum pump for exhausting the vacuum chamber 30. The turbo molecular pump 1 is a so-called composite wing type molecular pump including a turbo molecular pump part and a thread groove type pump part.
A casing 2 that forms an exterior body of the turbo molecular pump 1 has a substantially cylindrical shape, and constitutes a casing of the turbo molecular pump 1 together with a base 3 provided at a lower portion (exhaust port 6 side) of the casing 2. is doing. A structure that allows the turbo molecular pump 1 to perform an exhaust function, that is, a gas transfer mechanism is housed inside the housing.
This gas transfer mechanism is roughly composed of a rotating portion that is rotatably supported and a fixed portion that is fixed to the casing.

An inlet 4 for introducing gas into the turbo molecular pump 1 is formed at the end of the casing 2. A flange portion 5 is formed on the end surface of the casing 2 on the intake port 4 side so as to project to the outer peripheral side. The turbo molecular pump 1 and the vacuum chamber wall 31 are coupled to each other by being fixed using a fastening member such as a bolt through the flange portion 5.
The base 3 is formed with an exhaust port 6 for exhausting gas from the turbo molecular pump 1.

The rotating portion includes a shaft 7 that is a rotating shaft, a rotor 8 disposed on the shaft 7, a rotor blade 9 provided on the rotor 8, and a stator column 10 provided on the exhaust port 6 side (screw groove type pump portion). Etc. The shaft 7 and the rotor 8 constitute a rotor part.
The rotary blade 9 is composed of blades extending radially from the shaft 7 at a predetermined angle from a plane perpendicular to the axis of the shaft 7.
The stator column 10 is made of a cylindrical member having a cylindrical shape concentric with the rotation axis of the rotor 8.

A motor part 11 for rotating the shaft 7 at a high speed is provided in the middle of the shaft 7 in the axial direction.
Further, on the intake port 4 side and the exhaust port 6 side with respect to the motor part 11 of the shaft 7, radial magnetic bearing devices 12 and 13 for supporting the shaft 7 in the radial direction (radial direction), the shaft 7. An axial magnetic bearing device 14 for supporting the shaft 7 in the axial direction (axial direction) is provided at the lower end of the shaft.

A fixing portion is formed on the inner peripheral side of the housing. The fixed portion includes a fixed blade 15 provided on the intake port 4 side (turbo molecular pump portion), a thread groove spacer 16 provided on the inner peripheral surface of the casing 2, and the like.
The fixed wing 15 is composed of a blade that is inclined by a predetermined angle from a plane perpendicular to the axis of the shaft 7 and extends from the inner peripheral surface of the housing toward the shaft 7.
The fixed wings 15 of each stage are separated from each other by a cylindrical spacer 17.
In the turbo molecular pump section, the fixed blades 15 are formed in a plurality of stages alternately with the rotor blades 9 in the axial direction.

The thread groove spacer 16 is formed with a spiral groove on the surface facing the stator column 10. The thread groove spacer 16 faces the outer peripheral surface of the stator column 10 with a predetermined clearance (gap) therebetween. The direction of the spiral groove formed in the thread groove spacer 16 is a direction toward the exhaust port 6 when gas is transported in the spiral groove in the rotational direction of the rotor 8.
In addition, the depth of the spiral groove becomes shallower as it approaches the exhaust port 6, and the gas transported through the spiral groove is compressed as it approaches the exhaust port 6.
The turbo molecular pump 1 configured as described above performs evacuation processing in the vacuum chamber 30.

Since the turbo molecular pump 1 configured in this manner performs exhaust processing by rotating the rotating part at a high speed, the turbo molecular pump 1 is heated by collision heat of gas (gas) molecules or heat generated from the motor part 11. May be in a high temperature state.
When the radiant heat of the turbo molecular pump 1 is transmitted to the vacuum chamber 30 through the intake port 4 and the inside of the vacuum chamber 30 is in a high temperature state, the apparatus, sample, etc. handled in the vacuum chamber 30 are affected. There is a fear.
Therefore, the turbo molecular pump 1 according to the first embodiment is provided with a radiant heat reduction structure for reducing the influence of the radiant heat received by the vacuum chamber 30. This radiant heat reduction structure is provided upstream (intake port 4 side) of the gas transfer mechanism.

Next, the radiant heat reduction structure provided in the turbo molecular pump 1 will be described.
The radiant heat reduction structure is roughly composed of a heat shield mechanism and a cooling mechanism. First, the heat shield mechanism will be described with reference to FIGS. 1 and 2.
FIG. 2 is a diagram illustrating a schematic configuration of the heat shield mechanism according to the first embodiment. In FIG. 2, the heat shield mechanism is shown in a plan view as viewed from the intake port 4 side.
By the way, all objects emit heat energy in the form of electromagnetic waves unless the absolute temperature is zero.
Therefore, by reducing the electromagnetic waves radiated from the high temperature part and reaching the vacuum chamber 30, it is possible to reduce the influence of the thermal radiation of the turbo molecular pump 1 on the vacuum chamber 30.
Therefore, the heat shield mechanism according to the first embodiment has a structure in which electromagnetic waves radiated from the high temperature portion of the turbo molecular pump 1 are easily absorbed and are not easily radiated to the vacuum chamber 30 side.

The heat shield mechanism according to the first embodiment includes a heat shield plate 18, a support portion 19, and an uppermost spacer 17a.
The heat shield plate 18 is a disk (disk) member and functions as a baffle plate (baffle plate) for blocking heat radiated from the turbo molecular pump 1 to the vacuum chamber 30.
Radiant heat has the strongest radiation in the direction perpendicular to the surface, and the influence of radiation heat from the blades (rotary blades 9 and fixed blades 15) inclined with respect to the plane perpendicular to the axis of the shaft 7 is so great. It is not a thing.
That is, the influence of the radiant heat radiated in the vertical direction from the end face on the intake port 4 side of the rotor 8, that is, toward the vacuum chamber 30 is the strongest.
Therefore, the heat shield plate 18 is disposed so as to absorb heat (electromagnetic waves) radiated in the vertical direction from the end surface on the intake port 4 side of the rotor 8 from the vertical direction.
The heat shield plate 18 is disposed in the vicinity of the rotary blade 9. By disposing in the vicinity of the rotary blade 9, it is possible to reduce heat radiation that wraps around from the outer peripheral end of the heat shield plate 18.

The size (diameter) of the heat shield plate 18 is equal to the end surface area on the intake port 4 side of the rotor 8 in order to minimize the influence on the exhaust performance. That is, the region projected on the intake port 4 side of the region where the gas transfer path is formed (the region where the rotary blade 9 and the fixed blade 15 are disposed) and the heat shield plate 18 are projected on the intake port 4 side. So that it does not overlap with other areas.
In other words, in the heat shield plate 18, the region where the heat shield plate 18 is projected on the intake port 4 side and the region where the end surface region on the intake port 4 side of the rotor 8 is projected on the intake port 4 side overlap. Is arranged.
In this way, the heat shield plate 18 increases only the upper portion of the cylindrical portion of the rotor 8 (the portion excluding the region where the rotor blades 9 are disposed), that is, the exhaust resistance of the gas transferred by the action of the gas transfer mechanism. By arranging so as not to reach the region, it is possible to suppress a decrease in the exhaust performance of the turbo molecular pump 1 due to the provision of the heat shield plate 18.

Further, different surface treatments are applied to both surfaces of the heat shield plate 18.
The downstream side surface of the heat shield plate 18 (the surface on the exhaust port 6 side), that is, the surface facing the gas transfer mechanism composed of the rotary blade 9 and the fixed blade 15 is subjected to a surface treatment with high emissivity. Yes.
The emissivity indicates the absorptance of thermal energy (electromagnetic wave), and the higher the emissivity, the higher the absorptance of heat, and the lower the emissivity, the lower the absorptance of heat.
Examples of the surface treatment having a high emissivity applied to the downstream side surface of the heat shield plate 18 include an alumite coating process and a ceramic coating process in which the emissivity is 0.8 or more.
In this way, by performing a surface treatment with a high emissivity on the downstream side surface of the heat shield plate 18, the absorption rate of heat radiated from the rotor 8 or the like in the heat shield plate 18 can be improved. That is, since more heat can be absorbed in the heat shield plate 18, the amount of heat radiated to the vacuum chamber 30 side can be reduced.

On the other hand, the upstream side surface of the heat shield plate 18, that is, the surface facing the vacuum chamber 30 is subjected to surface treatment with low emissivity.
Examples of the surface treatment with low emissivity applied to the upstream side surface of the heat shield plate 18 include electropolishing, gold plating, and aluminum plating so that the emissivity is 0.1 or less.
The electrolytic polishing treatment is a method for obtaining a polishing effect by causing a metal polishing object to be a + (plus) electrode of an electrode and passing a direct current through the electrolytic solution to dissolve the metal surface.
In this way, by performing a surface treatment with a low emissivity on the upstream side surface of the heat shield plate 18, the amount of heat radiated from the heat shield plate 18 to the vacuum chamber 30 side can be reduced. That is, the amount of heat radiated to the vacuum chamber 30 side after being absorbed by the heat shield plate 18 can be reduced.

The support portion 19 is a member for supporting the heat shield plate 18 and is composed of four belt-like members extending in the radial direction from the heat shield plate 18 at intervals of 90 degrees.
Further, the support portion 19 not only functions as a support member, but also guides the heat of the heat shield plate 18 to the casing (casing 2) of the turbo molecular pump 1 and dissipates it from the turbo molecular pump 1 to the outside. It also functions as a heat conduction path.
The support portion 19 is formed of a thin band-like member in order to suppress a decrease in exhaust performance in the turbo molecular pump 1.
Note that the support portion 19 may be formed of a member having high thermal conductivity in order to improve thermal conductivity. For example, carbon fiber or the like is used as the member having high thermal conductivity.

The outer end portion of the support portion 19 is fixed to the uppermost spacer 17a.
The uppermost spacer 17a is arranged at the uppermost stage of the spacer 17, which is arranged to fix the stationary blades 15 of each stage with an interval in the axial direction, that is, the most upstream side.
The heat shield plate 18, the support portion 19, and the uppermost spacer 17a are integrally formed in order to suppress an increase in thermal resistance at each joint portion (connection portion). The heat shield mechanism is preferably a seamless integrated structure formed by machining, for example.
The heat shield mechanism can be easily arranged by assembling the uppermost spacer 17 a in the same manner as the other spacers 17 when assembling the turbo molecular pump 1.

In the heat shield mechanism arranged in this way, the heat absorbed by the heat shield plate 18 is transmitted to the uppermost spacer 17a via the support portion 19.
In the first embodiment, a cooling mechanism is provided for effectively cooling the heat transmitted to the uppermost spacer 17a or for efficiently cooling the heat shield mechanism.
The cooling mechanism is configured by a water cooling (liquid cooling) system including a cooling pipe 20 and a cooling pipe jacket 21.
A cooling pipe jacket 21 is provided on the outer periphery of the uppermost spacer 17a via the casing 2 so as to surround the casing 2 in the circumferential direction. A cooling pipe 20 is disposed inside the cooling pipe jacket 21 so that the casing 2 is inscribed therein.
The cooling pipe 20 is made of a tubular (tubular) member. In the water cooling (liquid cooling) system, a cooling material as a heat medium is caused to flow inside the cooling pipe 20, and cooling is performed by causing the cooling material to absorb heat.

In addition, in 1st Embodiment, although the cooling pipe 20 is comprised separately from the casing 2, the structure method of the cooling pipe 20 is not limited to this. For example, a groove may be formed on the outer peripheral surface of the casing 2, and a coolant may be supplied to the groove to provide the function of the cooling pipe 20. When the cooling pipe is configured in this way, the cooling material can directly absorb heat from the casing 2, so that the cooling efficiency can be improved.
Further, solder or heat conduction paste is attached to the gap between the cooling pipe jacket 21 and the cooling pipe 20 or the contact portion between the cooling pipe 20 and the casing 2 to further improve the efficiency of heat exchange in the cooling pipe 20. You may do it.

  As described above, in the first embodiment, by providing the cooling mechanism, the heat transmitted from the heat shield plate 18 to the uppermost spacer 17a can be effectively cooled, that is, the heat can be quickly discharged to the outside. Thus, the amount of heat radiated from the turbo molecular pump 1 to the vacuum chamber 30 side can be reduced by efficiently cooling the heat shield mechanism.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 3A is a diagram showing a schematic configuration of the turbo molecular pump 1 having the radiant heat reduction structure according to the second embodiment, and FIG. 3B is a diagram of an A portion in FIG. It is the figure which showed the enlarged view. FIG. 3 shows a sectional view of the turbo molecular pump 1 in the axial direction.
FIG. 3 also shows a part of the vacuum chamber 30 connected to the turbo molecular pump 1.
In addition, the same code | symbol is used for the same part (1st part) as 1st Embodiment shown in FIG. 1, and detailed description is abbreviate | omitted.

Also in the second embodiment, a radiant heat reduction structure for reducing the influence of the radiant heat received by the vacuum chamber 30 is provided. The radiation heat reducing structure in the second embodiment is provided in the vacuum chamber 30.
The radiant heat reduction structure in the second embodiment will be described below.
The radiant heat reduction structure is roughly composed of a heat shield mechanism and a cooling mechanism. First, the heat shield mechanism will be described with reference to FIGS. 3 (a) and 3 (b).
In order to suppress the electromagnetic wave radiated from the high temperature portion of the turbo molecular pump 1 from being radiated to the inside of the vacuum chamber 30, the heat shield mechanism according to the second embodiment is connected to the connection port (exhaust port) of the vacuum chamber 30. ) In the vicinity of the radiant heat (electromagnetic wave).

The heat shield mechanism according to the second embodiment includes a heat shield plate 22 and a support portion 23.
The heat shield plate 22 is a disk (disk) -like plate member whose diameter is larger than the diameter of the intake port 4 of the turbo molecular pump 1, and is a baffle plate for blocking heat radiated from the turbo molecular pump 1 ( It functions as a baffle plate.
The heat shield plate 22 is disposed so as to be parallel to the mounting surface of the turbo molecular pump 1 so as to face the surface where the intake port 4 of the turbo molecular pump 1 is formed.

Further, a surface facing the turbo molecular pump 1 of the heat shield plate 22, that is, a surface facing the gas transfer mechanism, is formed with a concavely curved surface (hereinafter referred to as a curved surface).
Specifically, an annular groove is formed so that the surface facing the gas transfer mechanism is a concavely curved surface. A plurality of (multi-stage) concentric circular grooves are formed.
By forming such a curved surface, radiant heat (electromagnetic waves) can be appropriately reflected toward the turbo molecular pump 1 side. Alternatively, the amount of heat (electromagnetic wave) radiated in the direction of the turbo molecular pump 1 out of the heat (electromagnetic wave) radiated from the heat shield plate 22 can be increased.

As shown in FIG. 2B, the annular groove formed in the heat shield plate 22 has a cross section in the axial direction of the surface facing the turbo molecular pump 1 among the surfaces forming the groove. ) As a symmetry axis and a quadratic curve (parabola) having a focal point in the direction in which the gas transfer mechanism is provided. That is, the annular groove formed in the heat shield plate 22 is formed such that a surface facing the gas transfer structure of the turbo molecular pump 1 among the surfaces forming the groove becomes a parabolic curved surface.
In detail, it is preferable that the focal point of the paraboloid is set downstream of the upper surface of the rotor 8.

The parabolic curved surface has a characteristic that when an electromagnetic wave collides (radiates) with this surface, the electromagnetic wave is reflected in a direction parallel to the target axis direction of the parabolic surface.
Therefore, when the heat (electromagnetic wave) radiated from the turbo molecular pump 1 collides with the annular groove of the heat shield plate 22, the heat (electromagnetic wave) is reflected along a direction parallel to the axial direction. That is, it is reflected to the turbo molecular pump 1 side.

In this way, by forming a groove having a predetermined angle on the surface of the heat shield plate 22 facing the turbo molecular pump 1, that is, a groove in which the groove angle is set based on the parabolic curved surface described above, The heat radiated from the rotor 8 or the like can be efficiently reflected to the turbo molecular pump 1 side.
Further, by forming a concave curved surface on the surface of the heat shield plate 22 facing the turbo molecular pump 1, that is, the surface facing the gas transfer mechanism, heat is transferred from the heat shield plate 22 to the turbo molecular pump 1 side. It can be made easy to radiate.
Accordingly, more heat can be appropriately reflected on the heat shielding plate 22 toward the turbo molecular pump 1, and the heat (electromagnetic waves) radiated from the heat shielding plate 22 toward the turbo molecular pump 1. Since the amount of heat (electromagnetic wave) radiated can be increased, the amount of heat radiated to the vacuum chamber 30 side can be reduced.

The support portion 23 is a member for supporting the heat shield plate 22, and includes a plurality of columnar members extending perpendicularly from the outer peripheral end surface of the heat shield plate 22 toward the turbo molecular pump 1. Adjacent support portions 23 are arranged with a sufficient interval so as not to affect the exhaust performance of the vacuum chamber 30.
Further, the support portion 23 has not only a function as a support member but also a function of a heat conduction path for guiding the heat of the heat shield plate 22 to the vacuum chamber wall 31 and radiating the heat to the outside.
For this reason, the support portion 23 is preferably formed of a member having high thermal conductivity in order to improve thermal conductivity.
One end of the support portion 23 is joined to the outer peripheral end of the heat shield plate 22, and the other end is fixed to the vacuum chamber wall 31. The heat shield plate 22 is attached to the vacuum chamber wall 31 by, for example, pressing the support portion 23 into an attachment hole provided in the vacuum chamber wall 31.
In addition, the arrangement | positioning method of the support part 23 for fixing the heat shield plate 22 is not limited to a perpendicular direction with respect to the heat shield plate 22. For example, the heat shield plate 22 may be disposed in the horizontal direction, that is, in the radial direction and fixed to the vacuum chamber wall 31. In this case, a cooling mechanism to be described later is provided in the vicinity of the connection portion between the support portion 23 and the vacuum chamber wall 31.

In the heat shield mechanism arranged in this way, the heat of the heat shield plate 22 is transmitted to the vacuum chamber wall 31 via the support portion 23.
In the second embodiment, a cooling mechanism is provided to effectively cool the heat transmitted to the vacuum chamber wall 31 or to efficiently cool the heat shield mechanism.
The cooling mechanism is configured by a water cooling (liquid cooling) system in which cooling pipes 24 and 25 are formed or arranged directly inside the vacuum chamber wall 31.
As with the cooling system in the first embodiment, the cooling pipes 24 and 25 cool the cooling pipes 24 and 25 by flowing a cooling medium as a heat medium so as to absorb the heat. .

  As described above, in the second embodiment, by providing the cooling mechanism, the heat transmitted from the heat shielding plate 22 to the vacuum chamber wall 31 through the support portion 23 is effectively cooled, or the heat shielding mechanism is efficiently used. Can be cooled. Thereby, since the electromagnetic waves radiated from the high temperature part of the turbo molecular pump 1 can be shielded near the exhaust port of the vacuum chamber 30, the amount of heat radiated to the inside of the vacuum chamber 30 can be reduced.

In addition, the surface treatment with a high emissivity is given to the downstream side surface of the support part 19, and the surface treatment with a low emissivity is given to the upstream side surface of the support part 19 like the heat shielding plate 18 to the support part 19 in 1st Embodiment. You may make it give. By applying such a surface treatment to the support portion 19, the amount of heat radiated to the vacuum chamber 30 side can be further reduced.
In addition, the heat treatment plate 22 according to the second embodiment has a surface treatment with a high emissivity on the downstream side surface (the surface facing the turbo molecular pump 1) of the heat insulation plate 22, as with the heat shield plate 18 in the first embodiment. And a surface treatment with a low emissivity may be applied to the upstream side surface of the heat shield plate 22 (the surface facing the central portion of the vacuum chamber 30). By applying such a surface treatment to the heat shield plate 22, the amount of heat radiated to the vacuum chamber 30 side can be further reduced.
Furthermore, you may make it form the annular groove provided in the heat insulation plate 22 in 2nd Embodiment in the heat insulation plate 18 in 1st Embodiment. By subjecting the heat shield plate 18 to such surface treatment (grooving), the amount of heat radiated to the vacuum chamber 30 side can be further reduced.

A surface treatment similar to the surface treatment with a low emissivity applied to the upstream side surface of the heat shield plate 18 in the first embodiment, that is, the surface facing the vacuum chamber 30, is the same as in the first example and the second example. You may make it apply to the area | region which opposes the vacuum chamber 30 and the member located in the most upstream side of a gas transfer mechanism, for example, the surface facing the inlet 4 of the rotor 8, the inlet 4 of the rotary blade 9, etc. .
In this way, by applying a surface treatment with a low emissivity to the region facing the vacuum chamber 30 and the member located on the most upstream side of the gas transfer mechanism, the amount of heat radiated from this region to the vacuum chamber 30 side can be reduced. Can be reduced.

Further, the same surface treatment as the surface treatment with a low emissivity applied to the upstream side surface of the heat shield plate 18 in the first embodiment, that is, the surface facing the vacuum chamber 30 is performed in the first and second embodiments. Of the members located on the most upstream side of the gas transfer mechanism in the example, the portion forming the gas transfer path and the region facing the vacuum chamber 30, for example, the surface facing the intake port 4 of the rotor blade 9, etc. May be.
Thus, by applying a surface treatment with a low emissivity to the region that forms the gas transfer path of the member located on the most upstream side of the gas transfer mechanism and the region facing the vacuum chamber 30, the vacuum chamber is removed from this region. The amount of heat radiated to the 30 side can be reduced.
In this case, a portion of the member located on the most upstream side of the gas transfer mechanism that does not form a gas transfer path and a region facing the vacuum chamber 30, for example, from the end surface on the intake port 4 side of the rotor 8 to the vacuum chamber 30 side. Since heat (electromagnetic wave) radiated to the heat shield plate 18 or the heat shield plate 22 collides with the heat shield plate 18 or the heat shield plate 22, not only can the propagation to the vacuum chamber 30 be suppressed, but also the rotor 8 and the rotor blade 9. It is possible to suppress heat from being accumulated in the rotating part (non-contact part) such as the shaft 7. As a result, the temperature rise of the rotating part can be suppressed.

  According to the first and second embodiments described above, the heat propagating from the turbo molecular pump 1 to the vacuum chamber 30 can be attenuated (decreased), so that an increase in the internal temperature of the vacuum chamber 30 can be appropriately suppressed. it can. Thereby, it is possible to realize more precise processing and higher-accuracy measurement inside the vacuum chamber 30.

It is the figure which showed schematic structure of the turbo-molecular pump provided with the radiation heat reduction structure which concerns on 1st Embodiment. It is the figure which showed schematic structure of the thermal-insulation mechanism which concerns on 1st Embodiment. (A) is the figure which showed schematic structure of the turbo-molecular pump provided with the radiation heat reduction structure which concerns on 2nd Embodiment, (b) is the figure which showed the enlarged view of the A section in (a). is there.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Turbo molecular pump 2 Casing 3 Base 4 Intake port 5 Flange part 6 Exhaust port 7 Shaft 8 Rotor 9 Rotary blade 10 Stator column 11 Motor part 12, 13 Radial direction magnetic bearing apparatus 14 Axial direction magnetic bearing apparatus 15 Fixed blade 16 Groove spacer 17 Spacer 17a Uppermost spacer 18, 22 Heat shield plate 19, 23 Support part 20, 24, 25 Cooling tube 21 Cooling tube jacket 30 Vacuum chamber 31 Vacuum chamber wall

Claims (5)

A casing formed with an intake port and an exhaust port;
A gas transfer mechanism provided in the casing and configured to transfer gas sucked from a vacuum device to the exhaust port via the intake port;
The emissivity of the surface facing the gas transfer mechanism is larger than the surface facing the vacuum device, arranged upstream from the gas transfer mechanism, and absorbs heat from the gas transfer mechanism and radiates it to the vacuum device. A heat shield plate to reduce the heat generated ,
Fixing means for fixing the heat shield plate;
A vacuum pump comprising:
A casing formed with an intake port and an exhaust port;
A gas transfer mechanism provided in the casing and configured to transfer gas sucked from a vacuum device to the exhaust port via the intake port;
A heat shield plate disposed upstream of the gas transfer mechanism and having a greater emissivity of a surface facing the gas transfer mechanism than a surface facing the vacuum device;
A fixing means for fixing the heat shield plate ,
The gas transfer mechanism has a rotor portion composed of a rotation shaft and a rotor fixed to the rotation shaft, and rotor blades arranged radially from the outer peripheral surface of the rotor portion,
The vacuum pump is characterized in that a region projected onto the gas transfer mechanism side of the heat shield plate is substantially equal to a region facing the intake port of the rotor portion .
3. The vacuum pump according to claim 2 , wherein the rotor blade located on the most upstream side is formed such that the emissivity of the surface facing the vacuum device is smaller than the emissivity of the other surfaces.
The vacuum pump according to any one of claims 1 to 3, further comprising a cooling mechanism that cools the heat shield plate.
  The vacuum according to any one of claims 1 to 4, wherein the heat shield plate has a concavely curved surface formed on a surface facing the gas transfer mechanism. pump.

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