Patent Grant
10364814
This application is a Section 371 National Stage Application of International Application No. PCT/JP2013/084634, filed Dec. 25, 2013, which is incorporated by reference in its entirety and published as WO 2014/119191 A1 on Aug. 7, 2014, not in English, and which claims priority to Japanese Patent Applications 2013-017234 filed on Jan. 31, 2013 and 2013-025936, filed on Feb. 13, 2013.
The present invention relates to a vacuum pump used as gas exhaust units and the like of process chambers and other sealed chambers in a semiconductor manufacturing apparatus, a flat panel display manufacturing apparatus, and a solar panel manufacturing apparatus.
As the vacuum pump of this type, for example, a vacuum pump described in Japanese Patent Application Laid-Open No. 2002-21775 has been publicly known. In the vacuum pump descried in Japanese Patent Application Laid-Open No. 2002-21775 (hereinafter referred to as “conventional vacuum pump”), as a means for preventing adhesion of a product in the pump, an alternating current is fed to a coil (25) illustrated in FIG. 2 of Japanese Patent Application Laid-Open No. 2002-21775 to raise the temperatures of a good heat conductor (24) and a heat radiation plate (20) and heat gas channels of a moving blade (5), a stationary blade (4), and a thread groove pump stage (9) through the heat radiation plate (20).
However, in the conventional vacuum pump, although the gas channels of the moving blade (5), the stationary blade (4), and the thread groove pump stage (9) can be heated as explained above, a lower side in a casing (1) cannot be heated (see FIG. 2 of Japanese Patent Application Laid-Open No. 2002-21775). Therefore, there is a problem in that the product easily adheres to the lower side in the casing (1) and an adhesion amount of the product in the vacuum pump as a whole is relatively large.
With the conventional vacuum pump, as illustrated in FIG. 2 of Japanese Patent Application Laid-Open No. 2002-21775, the coil (25) is housed in the good heat conductor (24) and a wire of the coil (25) is connected to a connector (26) piercing through the good heat conductor (24). Therefore, it is also likely that a trouble of a vacuum pump electric system due to magnetic flux leak occurs, for example, magnetic flux leaks from a through-hole (a hole through which the wire of the coil (25) is inserted) of the good heat conductor (24) and the wire of the coil (25) and electric components inside the vacuum pump malfunction because of the leaked magnetic flux.
Incidentally, in the conventional vacuum pump, gas in a gas inlet port (2) flows in the direction of an outlet port (3) through the gas channels of the moving blade (5), the stationary blade (4), and the thread groove pump stage (9), whereby the inlet port (2) side changes to a high vacuum and, on the other hand, the outlet port (3) side changes to a low vacuum (see the description of paragraph 0052 of Japanese Patent Application Laid-Open No. 2002-21775). When the outlet port (3) side changes to the low vacuum, a downstream side of the thread groove pump stage (9) close to the outlet port (3) also changes to the low vacuum.
However, with the conventional vacuum pump, as explained above, since the coil (25) is disposed downstream of the thread groove pump stage (9) that changes to the low vacuum (see FIG. 2 of Japanese Patent Application Laid-Open No. 2002-21775), insulating coating breakage of the coil (25) due to vacuum electric discharge occurs and the life of the coil (25) is short. There is also a problem in that a failure of the pump electric system such as a short circuit due to the insulating coating breakage of the coil (25) occurs and the vacuum pump cannot be stably continuously operated for a long period.
In the conventional vacuum pump, the connector (26) is attached to the lower outer circumference of the casing (1), the connector (26) and the coil (25) are connected by a wire (no reference numeral), and an alternating current is fed from the connector (26) to the coil (25) via the wire (see FIG. 2 of Japanese Patent Application Laid-Open No. 2002-21775).
However, with the conventional vacuum pump, an end side of the connector (26), in particular, a side to which the wire is connected is disposed in a vacuum in the casing (1) (see FIG. 2 of Japanese Patent Application Laid-Open No. 2002-21775). Therefore, an expensive vacuum connector has to be used as the connector (25) (see the description of paragraph 0051 of Japanese Patent Application Laid-Open No. 2002-21775). There is also a problem in that costs of the vacuum pump as a whole are inevitably high.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.
The present invention has been devised in order to solve the problems and it is an object of the present invention to reduce an adhesion amount of a product in a vacuum pump as a whole and effectively prevent a trouble of a vacuum pump electric system due to a magnetic flux leak. It is another object of the present invention to enable stable continuous operation of the vacuum pump for a long period and reduce costs of the vacuum pump as a whole.
In order to attain the object, according to a first invention, there is provided a vacuum pump including: a rotor enclosed in a pump case; a rotating shaft fixed to the rotor; a supporting means that rotatably supports the rotating shaft; a driving means that rotates the rotating shaft; and a thread-groove-exhaust-portion stator that forms a thread grove exhaust passage between the thread-groove-exhaust-portion stator and an outer circumferential side of or an inner circumferential side of the rotor. A heating portion is provided below the thread-groove-exhaust-portion stator. The heating portion includes a yoke, a coil, and a heating plate. The heating portion heats the yoke and the heating plate with electromagnetic induction heating by feeding an alternating current to the coil.
In the first invention, the rotor may be enclosed in a base spacer, a stator base may be disposed below the rotor, the heating portion may be provided between the thread-groove-exhaust-portion stator and the stator base and further include a heater spacer, and the heating plate may be in contact with the thread-groove-exhaust-portion stator and attached to the heater spacer, and at least one of the heater spacer, the thread-groove-exhaust-portion stator, the base spacer, and the stator bas may be heated by heating the yoke and the heating plate.
In the first invention, the heating portion may be configured by the heater spacer having a recess, the yoke disposed in the recess, the coil disposed on the yoke, and the heating plate that is in contact with the thread-groove-exhaust-portion stator and attached to the heater spacer to cover the recess.
In the first invention, the heating portion may be configured by the heater spacer having a recess, the yoke disposed in the recess, and the heating plate that has a groove and that is in contact with the thread-groove-exhaust-portion stator and attached to the heater spacer to cover the recess.
In the first invention, the heating portion may be configured by the heater spacer, the yoke attached to the heater spacer, the heating plate that has a groove and that is in contact with the thread-groove-exhaust-portion stator and attached to the heater spacer to enclose the yoke, and the coil disposed in the groove.
In the first invention, the vacuum pump may include: a connector mounting portion for mounting a connector on an outer side surface of the heater spacer; a wire through-hole formed in only the heater spacer or both of the heater spacer and the yoke and connecting with the connector mounting portion from the recess or the groove; and a wire inserted through the wire through-hole to connect the coil and the connector.
In the first invention, the heating portion may include: a temperature sensor attached to the heating plate, or the thread-groove-exhaust-portion stator, or the yoke; and a temperature control means that controls, on the basis of a detection value in the temperature sensor, the heating plate, or the thread-groove-exhaust-portion stator, or the yoke to have a predetermined temperature.
In the first invention, the heating portion may include: a temperature sensor attached to the coil; and a protection control means that controls, on the basis of a detection value in the temperature sensor, the coil not to have temperature exceeding a predetermined temperature.
In the first invention, as a means enabling the thread-groove-exhaust-portion stator to be heated preferentially over the base spacer and the stator base, a gap or an intermediate member having lower thermal conductivity may be disposed between the thread-groove-exhaust-portion stator and the base spacer or the stator base whereby the thread-groove-exhaust-portion stator and the base spacer or the stator base are not in direct contact with each other.
In the first invention, the heater spacer and the yoke may be integrally formed of a magnetic material.
In the first invention, the heater spacer and the base spacer may be integrally formed.
In the first invention, the stator base, the heater spacer, and the base spacer may be integrally formed.
In the first invention, the vacuum pump may adopt a configuration in which bolt through-holes are provided in the heater spacer, and the heating plate and the heater spacer and the heating plate are integrally attached to the thread-groove-exhaust-portion stator by fastening bolts inserted through the bolt through-holes, or a configuration in which bolt through-holes are provided in the thread-groove-exhaust-portion stator and the heating plate, and the thread-groove-exhaust-portion stator and the heating plate are integrally attached to the heater spacer by fastening bolts inserted through the bolt through-hole, or a configuration in which a bolt through-hole is provided in the thread-groove-exhaust-portion stator, and the thread-groove-exhaust-portion stator is attached to the base spacer or the stator base by a fastening bolt inserted through the bolt through-hole such that a lower end face of the thread-groove-exhaust-portion stator is in contact with the heating plate, and a configuration in which, as a means for enabling the thread-groove-exhaust-portion stator to be heated preferentially over the heater spacer, heat conduction from the heating plate to the heater spacer is reduced by providing a lightening portion near a boundary between the heater spacer and the heating plate.
In order to attain the object, according to a second invention, there is provided a vacuum pump including: a rotor enclosed in a pump case; a rotating shaft fixed to the rotor; a supporting means that rotatably supports the rotating shaft; a driving means that rotates the rotating shaft; and a thread-groove-exhaust-portion stator that forms a thread grove exhaust passage between the thread-groove-exhaust-portion stator and an outer circumferential side of or an inner circumferential side of the rotor. A heating portion is provided below the thread-groove-exhaust-portion stator. The heating portion includes a yoke, a coil, and a heating plate. The heating portion further includes a wire that connects the coil to a connector and a magnetic-flux-leak reducing means. The heating portion heats the yoke and the heating plate with electromagnetic induction heating by feeding an alternating current to the coil.
In the second invention, the rotor may be enclosed in a base spacer, a stator base may be disposed below the rotor, the heating portion may be provided between the thread-groove-exhaust-portion stator and the base stator and further include a heater spacer, the heating plate may be in contact with the thread-groove-exhaust-portion stator and attached to the heater spacer, the heating portion may further include a wire through-hole formed in only the heater spacer or both of the heater spacer and the yoke, the wire may be inserted through the wire through-hole, the magnetic-flux-leak reducing means may be mounted around the wire through-hole or the connector, the alternating-current may be fed from the connector via the wire, and the heating portion heats at least one of the heater spacer, the thread-groove-exhaust-portion stator, the base spacer, and the stator base by heating the yoke and the heating plate.
In the second invention, the heating portion may be configured by the heater spacer having a recess, the yoke disposed in the recess, the coil disposed on the yoke, and the heating plate that is in contact with the thread-groove-exhaust-portion stator and attached to the heater spacer to cover the recess.
In the second invention, the heating portion may be configured by the heater spacer having a recess, the yoke disposed in the recess, and the heating plate that has a groove and that is in contact with the thread-groove-exhaust-portion stator and attached to the heater spacer to cover the recess.
In the second invention, the heating portion may be configured by the heater spacer, the yoke attached to the heater spacer, the heating plate that has a groove and that is in contact with the thread-groove-exhaust-portion stator and attached to the heater spacer to enclose the yoke, and the coil disposed in the groove.
In the first or second invention, the heating portion may further include a seal means for making it possible to set pressure inside the recess or the groove to an outside pressure.
In the first or second invention, the heating portion may include an elastic O-ring functioning as the seal means, an O-ring groove for attaching the O-ring to the heating plate, and a minimum diameter portion provided between an opening end face and a bottom surface of the O-ring groove, and the minimum diameter portion may function as an O-ring-drop preventing means for preventing the O-ring from dropping by being formed larger than an inner diameter of the O-ring or being configured by a protrusion portion provided at an edge of the O-ring groove.
In the first invention, the rotor may be enclosed in a pump base, the thread-groove-exhaust-portion stator may consist of: an outer thread-groove-exhaust-portion stator on an outer circumference side of the rotor; and an inner thread-groove-exhaust-portion stator on an inner circumference side of the rotor, the heating portion may be provided below the inner thread-groove-exhaust-portion stator and the outer thread-groove-exhaust-portion stator, the heating plate may be in contact with the inner thread-groove-exhaust-portion stator or the outer thread-groove-exhaust-portion stator, the yoke may be disposed in the pump base, the coil may be disposed on the yoke and have a function of heating at least any one of the inner thread-groove-exhaust-portion stator, the outer thread-groove-exhaust-portion stator, and the pump base by heating the heating plate and the yoke, and the heating plate may be separated into a plurality of heating plates as two or more separated heating plates.
The separated heating plates may have different material properties, and exhibit different heat values respectively.
The separated heating plates each may have an asymmetrical cross-sectional shape with respect to a gap portion formed by the separation, and exhibit different heating ranges and heat values respectively.
At least any one of the separated heating plates may be formed of a laminated material, whereby a heat value is different for each of the separated heating plates.
Separated portions of the separated heating plates may overlap in a vertical direction and formed in a bent passage shape.
In the first invention, in the pump base, a recess in which the yoke is disposed, a connector mounting portion for mounting a connector, a wire through-hole that is connected with the recess from the connector mounting portion, and a wire inserted through the wire through-hole to connect the coil and the connector may be provided.
In the first or second invention, the vacuum pump may include a magnetic-flux-leak reducing means amounted around the wire through-hole or the connector.
The magnetic-flux-leak reducing means may be a shield pipe mounted in the wire through-hole.
The magnetic-flux-leak reducing means may be a shield plate mounted around the connector.
In the second invention, the rotor may be enclosed in a pump base, the thread-groove-exhaust-portion stator may consist of: an outer thread-groove-exhaust-portion stator on an outer circumference side of the rotor; and an inner thread-groove-exhaust-portion stator on an inner circumference side of the rotor, the heating portion may be provided below the inner thread-groove-exhaust-portion stator and the outer thread-groove-exhaust-portion stator, the heating plate may be in contact with the inner thread-groove-exhaust-portion stator or the outer thread-groove-exhaust-portion stator, the yoke may be disposed in the pump base, the coil may be disposed on the yoke and have a function of heating at least any one of the inner thread-groove-exhaust-portion stator, the outer thread-groove-exhaust-portion stator, and the pump base by heating the heating plate and the yoke, a connector mounting portion for mounting the connector may be provided in the pump base, the magnetic-flux-leak reducing means may be a shield pipe formed of a magnetic material, and the wire is covered with the shield pipe.
A shield plate formed of a magnetic material may be set around the connector.
In the present invention, as explained above, the heating portion is provided below the thread-groove-exhaust-portion stator and, as a specific configuration of the heating portion, the vacuum pump adopts a configuration in which the yoke and the heating plate are heated by the electromagnetic induction heating by feeding the alternating current to the coil to heat members around the lower part of the thread-groove-exhaust-portion stator such as the heater spacer, the thread-groove-exhaust-portion stator, the base spacer, and the stator base. Consequently, adhesion of a product in the base spacer and the stator base can be prevented by the heating of the base spacer and the stator base by the heating portion. Therefore, it is possible to reduce an adhesion amount of the product in the vacuum pump as a whole.
In particular, according to second invention, as the specific configuration of the heating portion, the vacuum pump adopts the configuration including the coil and including the magnetic-flux-leak reducing means. Therefore, a magnetic flux leak of the coil can be reduced by the magnetic-flux-leak reducing means. It is possible to effectively prevent a trouble of a vacuum pump electric system due to the magnetic flux leak such as a malfunction of electric components inside the vacuum pump due to leaked magnetic flux.
In the specific configuration of the heating portion, with the configuration including the seal means for making it possible to set the inside of the recess or the groove to the outside pressure, the inside of the recess or the groove can be set to the outside pressure that does not cause vacuum electric discharge such as the atmospheric pressure or pressure close to the atmospheric pressure. Consequently, it is possible to prevent insulating coating breakage of the coil due to the vacuum electric discharge and attain extension of the life of the coil. It is possible to prevent a failure of the electric system of the vacuum pump such as a short circuit due to the insulating coating breakage of the coil. Therefore, it is possible to stably continuously operate the vacuum pump for a long period.
Further, with the configuration including the seal means, the inside of the recess or the groove can be set to, for example, the atmospheric pressure or the pressure close to the atmospheric pressure. Therefore, when a connector is connected to the coil in the recess or the groove via the wire, it is unnecessary to use an expensive vacuum connector as the connector. An inexpensive connector can be used. Therefore, it is possible to attain a reduction in costs of the vacuum pump as a whole.
The Summary is provided to introduce a selection of concepts in a simplified form that are further described in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
Preferred embodiments of the present invention are explained in detail below with reference to the accompanying drawings.
A vacuum pump P1 shown in
The armor case 1 is formed in a cylindrical shape obtained by integrally coupling a cylindrical pump case 1A and a base spacer 1B using fastening bolts in a cylinder axial direction of the pump case 1A and the base spacer 1B. An upper end side of the pump case 1A is opened as a gas inlet port 2. A gas outlet port 3 is provided on a lower end side surface of the base spacer 1B.
The gas inlet port 2 is connected to a not-shown sealed chamber in a high vacuum such as a process chamber of a semiconductor manufacturing apparatus by not-shown fastening bolts provided in a flange 1C at the upper edge of the pump case 1A. The gas outlet port 3 is connected to a not-shown auxiliary pump.
A cylindrical stator base 4 incorporating various electric components is provided in the center in the pump case 1A. The stator base 4 is integrally erected on the inner bottom of the base spacer 1B. However, as another embodiment, for example, the stator base 4 may be formed as a component separate from the base spacer 1B and threaded and fixed to the inner bottom of the base spacer 1B.
A rotating shaft 5 is provided on the inner side of the stator base 4. The rotating shaft 5 is disposed such that the upper end thereof faces the direction of the gas inlet port 2 and the lower end thereof faces the direction of the base spacer 1B. The upper end of the rotating shaft 5 is provided to project upward from a cylindrical upper end face of the stator base 4.
The rotating shaft 5 is supported rotatably in a radial direction and an axial direction by two sets of radial magnetic bearings 10 and one set of an axial magnetic bearing 11 functioning as a supporting means. In this state, the rotating shaft 5 is driven to rotate by a driving motor 12 functioning as a driving unit. The supporting means (the radial magnetic bearings 10 and the axial magnetic bearing 11) and the driving unit (the driving motor 12) are housed in the stator base 4. Note that the radial magnetic bearings 10, the axial magnetic bearing 11, and the driving motor 12 are publicly known. Therefore, specific detailed explanation thereof is omitted.
A rotor 6 is provided on the outer side of the stator base 4. The rotor 6 is enclosed in the pump case 1A and the base spacer 1B. The rotor 6 is formed in a cylindrical shape surrounding the outer circumference of the stator base 4 and in a shape obtained by coupling two cylinder bodies (a first cylinder body 61 and a second cylinder body 62), which have different diameters, in a cylinder axis direction thereof using a coupling section 60 of an annular plate body located substantially in the middle of the rotor 6.
At the upper end of the first cylinder body 61, as a member configuring an upper end surface thereof, an end member is integrally provided. The rotor 6 is fixed to the rotating shaft 5 via the end member 63. The rotor 6 is rotatably supported around the axis thereof (the rotating shaft 5) by the radial magnetic bearings 10 and the axial magnetic bearing 11 via the rotating shaft 5.
The rotor 6 in the vacuum pump P1 shown in
<<Detailed Configuration of the Blade Exhaust Section Pt>>
In the vacuum pump P1 shown in
A plurality of rotary blades 13 are integrally provided on the outer circumferential surface of the rotor 6 further on the upstream side than substantially the middle of the rotor 6, specifically, the outer circumferential surface of the first cylinder body 61 configuring the rotor 6. The plurality of rotary blades 13 are radially disposed side by side centering on the rotation center axis (the rotating shaft 5) of the rotor 6 or the axis of the armor case 1 (hereinafter referred to as “vacuum pump axis”).
On the other hand, a plurality of fixed blades 14 are provided on the inner circumference side of the pump case 1A. The plurality of fixed blades 14 are also radially disposed side by side centering on the vacuum pump axis.
In the vacuum pump P1 shown in
Note that all the rotary blades 13 are blade-like cut products cut out integrally with an outer diameter machined section of the rotor 6. The rotary blades 13 are inclined at an angle optimum for exhaust of gas molecules. All the fixed blades 14 are also inclined at an angle optimum for exhaust of gas molecules.
<<Explanation of an Exhaust Operation by the Blade Exhaust Section Pt>>
In the blade exhaust section Pt configured as explained above, the rotating shaft 5, the rotor 6, and the plurality of rotary blades 13 integrally rotate at high speed according to the start of the driving motor 12. The rotary blade 13 at the top stage gives a momentum in the downward direction to gas molecules injected from the gas inlet port 2. The gas molecules having the momentum in the downward direction are sent by the fixed blades 14 to the rotary blade 13 side at the next stage. The giving of the momentum to the gas molecules and the sending action explained above are repeatedly performed in multiple stages, whereby the gas molecules on the gas inlet port 2 side are exhausted to sequentially shift toward downstream of the rotor 6.
<<Detailed Configuration of the Thread Groove Exhaust Section Ps>>
In the vacuum pump P1 shown in
The rotor 6 further on the downstream side than substantially the middle of the rotor 6, specifically, the second cylinder body 62 configuring the rotor 6 is a portion that rotates as a rotating member of the thread groove exhaust section Ps. The second cylinder body 62 is inserted and housed, via a predetermined gap, between thread-groove-exhaust-portion stators 18A and 18B having an inner/outer double cylindrical shape of the thread groove exhaust section Ps.
The thread-groove-exhaust-portion stator 18A of the thread-groove-exhaust-portion stators 18A and 18B having the inner/outer double cylindrical shape is a cylindrical fixed member disposed such that the outer circumferential surface thereof are opposed to the inner circumferential surface of the second cylinder body 62. The thread-groove-exhaust-portion stator 18A is disposed to be surrounded by the inner circumference of the second cylinder body 62.
On the other hand, the thread-groove-exhaust-portion stator 18B on the outer side is a cylindrical fixed member disposed such that the inner circumferential surface thereof is opposed to the outer circumferential surface of the second cylinder body 62. The thread-groove-exhaust-portion stator 18B is disposed to surround the outer circumference of the second cylinder body 62.
In an outer circumferential section of the thread-groove-exhaust-portion stator 18A on the inner side, as a means for forming a thread groove exhaust passage R1 on the inner circumference side of the rotor 6 (specifically, on the inner circumference side of the second cylinder body 62), a thread groove 19A changing in a taper cone shape reduced in diameter downward is formed. The thread groove 19A is engraved in a spiral shape from the upper end to the lower end of the thread-groove-exhaust-portion stator 18A. A thread groove exhaust channel is formed on the inner circumference side of the second cylinder body 62 (hereinafter referred to as “inner thread groove exhaust channel R1”) by the thread-groove-exhaust-portion stator 18A including the thread groove 19A. Note that, as shown in
In an inner circumferential section of the thread-groove-exhaust-portion stator 18B on the outer side, as a means for forming a thread groove exhaust passage R2 on the outer circumferential side of the rotor 6 (specifically, the outer circumference side of the second cylinder body 62), a thread groove 19B same as the thread groove 19A is formed. A thread groove exhaust channel is formed on the outer circumference side of the second cylinder body 62 (hereinafter referred to as “outer thread groove exhaust channel R2”) by the thread-groove-exhaust-portion stator 18B including the thread groove 19B. Note that, as shown in
Although not shown in the figure, the inner thread groove exhaust channel R1 or the outer thread groove exhaust channel R2 may be provided by forming the thread grooves 19A and 19B explained above on the inner circumferential surface or the outer circumferential surface or both of the surfaces of the second cylinder body 62.
In the thread groove exhaust section Ps, in order to transfer gas while suppressing the gas according to a drag effect in the thread groove 19A and on the inner circumferential surface of the second cylinder body 62 and a drag effect in the thread groove 19B and on the outer circumferential surface of the second cylinder body 62, the depth of the thread groove 19A is set to be the largest on an upstream inlet side of the inner thread groove exhaust channel R1 (a channel opening end closer to the gas inlet port 2) and the smallest on a downstream outlet side of the inner thread groove exhaust channel R1 (a channel opening end closer to the gas outlet port 3). The same applies to the thread groove 19B.
An upstream inlet of the outer thread groove exhaust channel R2 is connected with a gap between a rotary blade 13E at the bottom stage among the rotary blades 13 disposed in the multiple stages and an upstream end of a connection opening H explained below (hereinafter referred to as “final gap G1”). As shown in
An upstream inlet of the inner thread groove exhaust channel R1 is opened toward the inner circumferential surface of the rotor 6 (specifically, the inner surface of the coupling section 60) substantially in the middle of the rotor 6. A downstream outlet of the channel R1 is connected with the gas outlet port 3 side through the annular confluence channel S1, the lateral hole channel S2, and the annular confluence channel S3.
The annular confluence channel S1 is formed to be connected with the downstream outlets of the inner and outer thread groove exhaust channels R1 and R2 and the lateral hole channel S2 by providing a predetermined gap between the end of the second cylinder body 62 and a heating portion 20 explained below (in the vacuum pump P1 shown in
The connection opening H is opened substantially in the middle of the rotor 6. The connection opening H is formed to pierce through the front and rear surfaces of the rotor 6 to function to guide a part of gas present on the outer circumference side of the rotor 6 to the inner thread groove exhaust channel R1. The connection opening H having such a function may be formed to, for example, pierce through the inner and outer surfaces of the coupling section 60 as shown in
<<Explanation of an Exhaust Operation in the Thread Groove Exhaust Section Ps>>
The gas molecules reaching the upstream inlet of the outer thread groove exhaust channel R2 and the final gap G1 according to the transfer by the exhaust operation of the blade exhaust section Pt explained above shift to the inner thread groove exhaust channel R1 from the outer thread groove exhaust channel R2 and the connection opening H. The shifted gas molecules shift toward the annular confluence channel S1 while being compressed from a transitional flow into a viscous flow according to an effect generated by the rotation of the rotor 6, that is, a drag effect on the outer circumferential surface of the second cylinder body 62 and in the thread groove 19B and a drag effect on the inner circumferential surface of the second cylinder body 62 and in the thread groove 19A. The viscous flow of the gas molecules reaching the annular confluence channel S1 flows into the annular confluence channel S3 through the lateral hole channel S2 and flows into the gas outlet port 3. The viscous flow of the gas molecules is exhausted to the outside from the gas outlet port 3 through the not-shown auxiliary pump.
<<Explanation of the Heating Portion in the Vacuum Pump Shown in
In the vacuum pump P1 shown in
The heating portion 20 includes, as shown in
The heating portion 20 heats the yoke 25 and the heating plate 23 with electromagnetic induction heating by feeding a high-frequency alternating current to the coil 26 to heat the heater spacer 22, the thread-groove-exhaust-portion stators 18A and 18B, the base spacer 1B, and the stator base 4.
The heater spacer 22 includes a connector mounting portion 101 for mounting a connector 100 on the outer side surface thereof, a wire through-hole 102 connecting with the connector mounting portion 101 from the recess 21, and a wire 103 of the coil 26 inserted through the wire through-hole 102 to connect the coil 26 and the connector 100. In the yoke 25 as well, the wire through-hole 102 is provided in order to insert the wire 103 of the coil 26 and a wire of a temperature sensor 51 explained below therethrough.
The connector 100, the connector mounting portion 101, the wire through-hole 102, the wire 103, and the wire of the temperature sensor 51 shown in
The seal means 24 seals an opening peripheral edge of the recess 21 with an O-ring or another seal member to thereby separate the recess 21 from a vacuum region such as the inner and outer thread groove exhaust channels R1 and R2 and make it possible to set only the inside of the recess 21 to the outside pressure.
The inside of the recess 21 is set to the atmospheric pressure when the atmosphere outside the heater spacer 22 is taken into the recess 21 via the wire through-hole 102. Note that it is also possible to take the outdoor air other than the atmosphere into the recess 21. The pressure in the recess 21 is not limited to the atmospheric pressure and only has to be pressure that does not cause insulting coating breakage of the coil 26 due to vacuum electric discharge.
The yoke 25 and the coil 26 are electrically insulated by an insulating plate 27 interposed between the yoke 25 and the coil 26. The heater spacer 22 is formed of an aluminum alloy. The heating plate 23 and the yoke 25 are formed of a magnetic material such as an iron-base material (e.g., pure iron, S15C, or S25C) or a stainless steel material having magnetism (e.g., a ferrite-base stainless steel material, SUS430, SUS304, or SUS420J2). The coil 26 is formed of a good conductor (e.g., a copper material).
When a high-frequency alternating current is fed to the coil 26, the coil 26, the heating plate 23, and the yoke 25 are electromagnetically coupled. An eddy current is generated on the insides of the heating plate 23 and the yoke 25. Then, since the heating plate 23 and the yoke 25 have peculiar electric resistances, Joule heat is generated in the heating plate 23 and the yoke 25. Iron loss heat generation occurs in the heating plate 23 and the yoke 25 and copper loss heat generation occurs in the coil 26. The thread-groove-exhaust-portion stators 18A and 18B and the heater spacer 22 are preferentially heated by these kinds of heat. Further, the base spacer 1B and the stator base 4 are also heated by heat conduction from the heater spacer 22.
The distance from the coil 26 to the heating plate 23 and the distance from the coil 26 to the yoke 25 equivalent to the thickness of the insulating plate 27 can be changed as appropriate according to necessity. However, from the viewpoint of preventing adhesion of a product on the thread-groove-exhaust-portion stator side, the distances are preferably set to distances with which the heating plate 23 can be more effectively heated than the yoke 25.
In the heating portion 20, the cross-sectional shape of the yoke 25 is formed in an upward groove shape toward the ends of the thread-groove-exhaust-portion stators 18A and 18B. The upper end of the yoke 25 is disposed close to the heating plate 23. Consequently, the coil 26 in the yoke 25 is disposed in a space surrounded by the heating plate 23 and the yoke 25. Therefore, a magnetic flux leak of the coil 26 decreases and improvement of heating efficiency is attained.
Further, the heating portion 20 includes the temperature sensor 51 attached to the heating plate 23 and a temperature control means (not shown in the figure) that controls, on the basis of a detection value in the temperature sensor 51, the heating plate 23 to have a predetermined temperature.
Further, the heating portion 20 may include a temperature sensor (not shown in the figure) attached to the coil 26 and a temperature control means (not shown in the figure) that controls, on the basis of a detection value in the temperature sensor 51, the coil 26 not to have temperature exceeding a predetermined temperature.
As a method of attaching the temperature sensor 51 to the heating plate 23, it is possible to adopt a method of forming a sensor attachment hole 50, which is opened only on the recess 21 side, in the heating plate 23 and inserting the temperature sensor 51 into the sensor attachment hole 50 and fixing the temperature sensor 51 with an adhesive or the like as shown in
In the vacuum pump P1 shown in
In the vacuum pump P1 shown in
In particular, in the attachment structure example shown in
In the attachment structure example shown in
After the heating portion 20 is assembled to the base spacer 1B as shown in
In the attachment structure example shown in
In the heating portion 20, as a method of fixing the recess 21 and the yoke 25, it is possible to adopt a method of pressing the yoke 25 into the recess 21, a method of fixing the recess 21 and the yoke 25 with a not-shown thread, or a method of bonding the yoke 25 in the recess 21.
In the heating portion 20, as a method of fixing the yoke 25 and the coil 26, it is possible to adopt a method of filling resin or the like in the yoke 25 to mold the entire coil 26 with the resin or the like.
Further, in the heating portion 20, as a method of fixing the heating plate 23 and the thread-groove-exhaust-portion stators 18A and 18B, it is possible to adopt a method of providing a projection on the surface of the heating plate 23, for example, as shown in
Note that, in the heating portion 20, the heating plate 23 and the thread-groove-exhaust-portion stators 18A and 18B are fastened by the fastening bolts BT1 as explained above. Therefore, the fixing methods by the press-in and the bonding of the heating plate 23 and the thread-groove-exhaust-portion stators 18A and 18B explained above can be omitted according to necessity.
When cooling unit is attached in the vacuum pump P1 shown in
The heater spacer 22 and the base spacer 1B are separate components. The heater spacer 22 has a form like a relatively thin doughnut shape plate as a whole. Therefore, manufacturing work of the heater spacer 22 by the casting and work itself for casting the water cool pipe 7 in the heater spacer 22 in the casting are relatively easy.
In the structure example shown in
As a method of mounting the heat conduction pipe 8 on the exhaust pipe 30, for example, it is possible to adopt a method of attaching the heat conduction pipe 8 by vertically dividing the heat conduction pipe 8 into a plurality of pieces (e.g., into two) in the axial direction thereof or a method of attaching the heat conduction pipe 8 in size equal to or smaller than the diameter of the exhaust pipe 30.
The heater spacer 22 of the heating portion 20 explained above can be integrated with the base spacer 1B as in the structure example shown in
The heater spacer 22, the base spacer 1B, and the stator base 4 of the heating portion 20 explained above can also be integrated as shown in
The attachment structure example shown in
As in the attachment example shown in
The vacuum pump P1 shown in
The vacuum pump P2 shown in
The heating portion 20 adopted in the vacuum pump P1 shown in
As the gas outlet port 3 shown in
A vacuum pump P3 shown in
The heating portion 20 adopted in the vacuum pump P1 shown in
The protrusion 28 is disposed to be opposed to the inner circumference of the second cylinder body 62 to form a clearance seal and reduces intrusion of gas, which reaches the annular confluence channel S1 from a downstream outlet of the thread groove exhaust channel R2, into an inner side space of the rotor 6.
Note that, in the heating portion 20 shown in
The heater spacer 22 of the heating portion 20 can also be formed of a magnetic material. In this case, as in the structure example shown in
In the structure example shown in
In the heating portion 20, as explained above, the wire through-hole 102 is also formed in the yoke 25 in order to insert the wire 103 of the coil 26 and the wire of the temperature sensor 51 therethrough. Therefore, it is likely that magnetic flux of the coil 26 leaks to the outside through the wire through-hole 102.
On the other hand, in the structure example shown in
Note that, in the vacuum pump P1 shown in
Incidentally, in the structure example shown in
A heating portion 70 shown in
The heating portion 70 shown in
The heating portion 70 is configured to heat the yoke 73 and the heating plate 74 with electromagnetic induction heating by feeding a high-frequency alternating current to the coil 77 to thereby heat the heater spacer 71, the thread-groove-exhaust-portion stators 18A and 18B, the base spacer 1B, and the stator base 4.
The O-ring 83 seals opening peripheral edges of the recess 72 and the groove 75 shown in
In the case of a configuration including the O-ring 83, as shown in
Further, the O-ring groove 84 and the O-ring 83 shown in
In
When a high-frequency alternating current is fed to the coil 77, the coil 77, the heating plate 74, and the yoke 73 are electromagnetically coupled. An eddy current is generated on the insides of the heating plate 74 and the yoke 73. Then, since the heating plate 74 and the yoke 73 have peculiar electric resistances, Joule heat is generated in the heating plate 74 and the yoke 73. Iron loss heat generation occurs in the heating plate 74 and the yoke 73 and copper loss heat generation occurs in the coil 77. The thread-groove-exhaust-portion stators 18A and 18B and the heater spacer 71 are preferentially heated by these kinds of heat. Further, the base spacer 1B and the stator base 4 are also heated by heat conduction from the heater spacer 71.
The distance from the coil 77 to the yoke 73 and the distance from the coil 77 to the heating plate 74 equivalent to the thickness of the insulating plate 81 can be changed as appropriate according to necessity. However, from the viewpoint of preventing adhesion of a product on the thread-groove-exhaust-portion stator side, the distances are preferably set to distances with which the heating plate 74 can be more effectively heated than the yoke 73.
In the heating portion 70, the cross-sectional shape of the yoke 73 is formed in a plate shape. The upper end of the yoke 73 is disposed close to the heating plate 74. Consequently, the coil 77 in the heating plate 74 is disposed in a space surrounded by the heating plate 74 and the yoke 73 formed of the magnetic material. Therefore, a magnetic flux leak of the coil 77 decreases and improvement of heating efficiency is attained.
The heating portion 70 includes a temperature sensor 79 attached to a sensor attachment hole 78 and a temperature control means (not shown in the figure) that controls, on the basis of a detection value in the temperature sensor 79, the heating plate 74 to have a predetermined temperature.
Further, the heating portion 70 may include a temperature sensor 80 attached to the coil 77 and a temperature control means (not shown in the figure) that controls, on the basis of a detection value in the temperature sensor 80, the coil 77 not to have temperature exceeding a predetermined temperature.
For the attachment of the temperature sensor 79 to the heating plate 74, as shown in
In the heating portion 70 shown in
The heating portion 70 shown in
As explained above, in the vacuum pumps P1, P2, and P3 in the first to third embodiments, as the specific configuration of the heating portion 20 (70), the heating portion 20 (70) adopts a configuration in which the yoke 25 (73) and the heating plate 23 (74) are heated by the electromagnetic induction heating by feeding the alternating current to the coil 26 (77) to heat the heater spacer 22 (71), the thread-groove-exhaust-portion stators 18A and 18B, the base spacer 1B, and the stator base 4. Therefore, adhesion of a product in the base spacer 1B and the stator base 4 can also be prevented by the heating of the base spacer 1B and the stator base 4 by the heating portion 20 (70). Consequently, it is possible to reduce an adhesion amount of the product in the vacuum pump as a whole.
With the vacuum pumps P1, P2, and P3 in the first to third embodiments, as a specific configuration of the heating portion 20 (70), the heating portion 20 (70) adopts a configuration in which the coil 26 (77) is disposed in the recess 21 of the heater spacer 22 (the groove 75 of the heating plate 74) that can be set to the outside pressure by the seal means 24 (83) and a configuration in which the inside of the recess 21 (the groove 75) is set to the outside pressure that does not cause vacuum electric discharge such as the atmospheric pressure or pressure close to the atmospheric pressure. Therefore, it is possible to prevent insulating coating breakage of the coil 26 (77) due to the vacuum electric discharge and attain extension of the life of the coil 26 (77). It is possible to prevent a failure of the electric system of the vacuum pump such as a short circuit due to insulating coating breakage of the coil 26 (77). It is possible to stably continuously operate the vacuum pump for a long period.
Further, in the vacuum pumps P1, P2, and P3 in the first to third embodiments, the inside of the recess 21 (the groove 75) is set to, for example, the atmospheric pressure or pressure close to the atmospheric pressure. Therefore, when the wire 103 of the coil 26 (77) in the recess 21 (the groove 75) is connected to the connector 100, it is unnecessary to use an expensive vacuum connector as the connector 100. An inexpensive connector can be used. Therefore, it is possible to attain a reduction in costs of the vacuum pump as a whole.
In a vacuum pump P4 shown in
<<Explanation of a Heating Portion in the Vacuum Pump Shown in
In the vacuum pump P4 shown in
The heating portion 20 shown in
The heating portion 20 shown in
In the heating portion 20 shown in
The heating plate 23 in the heating portion 20 shown in
As a specific structure example of the plurality of separated heating plates 23, in the vacuum pump P4 shown in
In the vacuum pump P4 shown in
In the heating portion 20 shown in
Referring to
In
The inner and outer separated heating plates 23A and 23B may be formed of magnetic materials having the same material properties to thereby set a heat value of each of the separated heating plates 23A and 23B to be substantially the same. However, as another embodiment, the separated heating plates 23A and 23B may be formed of magnetic materials having different material properties to thereby vary the heat value for each of the separated heating plates 23A and 23B.
The inner thread-groove-exhaust-portion stator 18A and the outer thread-groove-exhaust-portion stator 18B sometimes have different heat values because of, for example, differences in mass, a material, and a heat loss thereof. For example, the heat value of the outer thread-groove-exhaust-portion stator 18B is sometimes larger than the heat value of the inner thread-groove-exhaust-portion stator 18A. In this case, for example, the heat value of the separated heating plate 23B on the outer side can be set larger than the heat value of the separated heating plate 23A on the inner side by forming the separated heating plate 23B on the outer side from a pure iron-base material and, on the other hand, forming the separated heating plate 23A on the inner side from a stainless steel material. Consequently, it is possible to heat by the heating plate 25 the thread-groove-exhaust-portion stators 18A and 18B according to the heat values of the thread-groove-exhaust-portion stators 18A and 18B, for example, heat the inner thread-groove-exhaust-portion stator 18A and the outer thread-groove-exhaust-portion stator 18B to substantially the same temperatures or heat the inner thread-groove-exhaust-portion stator 18A and the outer thread-groove-exhaust-portion stator 18B to respective target temperatures.
Besides, as a method of changing material properties, there is a method of adding an additive to a material. For example, ceramics are added to the material of the separated heating plates to partially change physical properties such as electric resistance of the material. Consequently, it is possible to change a heat value concerning not only the entire separated heating plates but also a part of the separated heating plates.
Like the heating plate 23 shown in
In the heating plate 23 shown in
In particular, in the heating plate 23 shown in
On the other hand, in the heating plate 23 shown in
In the heating plate 23 shown in
As still another embodiment in which the laminated material explained above is adopted, it is also possible to set the heating value to be different for each of the separated heating plates 23A and 23B by forming both of the inner and outer separated heating plates 23A and 23B from the laminated material and changing the number of laminated materials in the inner and outer separated heating plates 23A and 23B.
In the heating plate 23 shown in
Since the separation gap G3 is an air gap, a magnetic flux leak of the coil 26 from the separation gap G3 to the upper side of the heating plate 23 is inevitable. However, with the superimposed structure of the separated heating plates 23A and 23B shown in
In particular, in the superimposed structure of the separated heating plates 23A and 23B shown in
In the vacuum pump P4 shown in
In
In the heating portion 20 shown in
Consequently, the coil 26 in the yoke 25 is disposed in a space surrounded by the heating plate 23 and the yoke 25 formed of the magnetic material. Therefore, a magnetic flux leak of the coil 26 is little.
In the heating portion 20 shown in
The vacuum pump P4 shown in
The heating portion 20 shown in
In the vacuum pump P4 shown in
The heating portion 20 shown in
The heating portion 20 shown in
Further, the heating portion 20 shown in
In the heating portion 20 shown in
The vacuum pump P4 shown in
As explained above, in the vacuum pump P4 in the fourth embodiment, as a specific configuration of the heating portion 20, the heating portion 20 has a function of heating the heating plate 23 and the yoke 25 with electromagnetic induction heating by feeding an alternating current to the coil 26 to thereby heat the inner thread-groove-exhaust-portion stator 18A, the outer thread-groove-exhaust-portion stator 18B, and the pump base 1D. Therefore, it is possible to prevent adhesion of a product in the pump base 1D by heating the pump base 1D with the heating portion 20. In addition, it is also possible to heat the stator column 4 with heat conduction from the pump base 1D and prevent adhesion of the product in the stator column 4. Therefore, it is possible to reduce an adhesion amount of the product in the vacuum pump P4 as a whole.
The vacuum pump P4 in the fourth embodiment adopts a configuration in which the shield pipe 200 formed of the magnetic material is mounted on the wire through-hole 102 and a configuration in which the shield plate 201 formed of the magnetic material is disposed around the connector 100. Therefore, it is possible to reduce a magnetic flux leak of the coil 26 with the shield pipe 200 and the shield plate 201. It is possible to effectively prevent a trouble of a vacuum pump electric system due to the magnetic flux leak such as a malfunction of electric components inside the vacuum pump P4 due to leaked magnetic flux.
Further, the vacuum pump P4 in the fourth embodiment adopts, as a specific configuration of the heating portion 20, a configuration in which the heating plate 23 is separated into a plurality of heating plates as the two or more separated heating plates 23A and 23B in contact with one of the inner and outer thread-groove-exhaust-portion stators 18A and 18B. Therefore, for example, at a pump assembly stage in which the heating plate 23 is attached in contact with the ends of the inner and outer thread-groove-exhaust-portion stators 18A and 18B, the heating plate 23 can be individually attached to the respective inner and outer thread-groove-exhaust-portion stators 18A and 18B as the separated heating plates 23A and 23B separated into two or more. Therefore, even when a machining dimension error or an attachment dimension error in the length direction in the inner and outer thread-groove-exhaust-portion stators 18A and 18B is present, it is possible to easily attach the heating plate 23 to the inner and outer thread-groove-exhaust-portion stators 18A and 18B without being affected by the errors. Since it is unnecessary to highly accurately set a machining dimension and an attachment dimension in the length direction in the inner and outer thread-groove-exhaust-portion stators 18A and 18B, it is possible to attain a reduction in costs of the vacuum pump P4 as a whole.
The structure examples of the heating plates 23 shown in
In the vacuum pump P4 in the fourth embodiment, the thread groove exhaust section Ps configures the thread groove pump parallel flow type. However, the present invention is not limited to the thread groove exhaust section Ps of this type. The present invention can be applied to all vacuum pumps including thread-groove-exhaust-portion stators. As the vacuum pumps to which the present invention can be applied, there are, for example, a type in which the thread groove exhaust section Ps including only an outer thread-groove-exhaust-portion stator is configured and a type in which the thread groove exhaust section Ps exhausts gas with an outer thread groove and thereafter successively exhausts gas with an inner thread groove.
he vacuum pumps P1, P2, P3, and P4 in the first to fourth embodiments explained above include the blade exhaust section Pt and the thread groove exhaust section Ps. However, the present invention can be applied to a vacuum pump including only the thread groove exhaust section Ps.
Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-017234 | Jan 2013 | JP | national |
| 2013-025936 | Feb 2013 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2013/084634 | 12/25/2013 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2014/119191 | 8/7/2014 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 6504379 | Jackson | Jan 2003 | B1 |
| 6629824 | Yamauchi | Oct 2003 | B2 |
| 6793466 | Miyamoto | Sep 2004 | B2 |
| 20030180162 | Beyer et al. | Sep 2003 | A1 |
| 20070052389 | Kooij | Mar 2007 | A1 |
| Number | Date | Country |
|---|---|---|
| S5129753 | Mar 1976 | JP |
| H07145952 | Jun 1995 | JP |
| 2002021775 | Jan 2002 | JP |
| 2002048088 | Feb 2002 | JP |
| 2002180988 | Jun 2002 | JP |
| 2004241215 | Aug 2004 | JP |
| 2012179409 | Sep 2012 | JP |
| Entry |
|---|
| PCT International Search Report dated Apr. 8, 2014 for corresponding PCT Application No. PCT/JP2013/084634. |
| The specification and drawings annexed to the request of Japanese Utility Model Application No. 58093/1991 (Laid-open No. 12691/1993) (Shimadzu Corp.), Feb. 19, 1993, entire text; all drawings (family: none). |
| Number | Date | Country | |
|---|---|---|---|
| 20160025096 A1 | Jan 2016 | US |
