U.S. patent application number 13/877274 was filed with the patent office on 2013-08-15 for vacuum pump control device and vacuum pump.
This patent application is currently assigned to EDWARDS LIMITED. The applicant listed for this patent is Takashi Kabasawa, Hideki Omori. Invention is credited to Takashi Kabasawa, Hideki Omori.
Application Number | 20130209272 13/877274 |
Document ID | / |
Family ID | 45927494 |
Filed Date | 2013-08-15 |
United States Patent
Application |
20130209272 |
Kind Code |
A1 |
Omori; Hideki ; et
al. |
August 15, 2013 |
VACUUM PUMP CONTROL DEVICE AND VACUUM PUMP
Abstract
An object of the present invention is to improve, using a simple
configuration, heat dissipation of a regenerative resistor that is
disposed in a vacuum pump control device (controller) connected to
a vacuum pump. The regenerative resistor disposed in the vacuum
pump control device is stored in an aluminum die-cast casing. More
concretely, a housing of the vacuum pump control device is prepared
by aluminum die casting (metal mold casting). A regenerative
resistor storing portion (aluminum die-cast casing) provided with a
hollow portion is provided on a top panel of the aluminum die cast,
the hollow portion being designed to have a size accommodating the
entire regenerative resistor. The regenerative resistor is fitted
into the hollow portion, and an opening section of the hollow
portion is sealed with an aluminum sheet of the same material as
that of the casing. In this manner, the regenerative resistor can
removably be stored in the aluminum die-cast casing.
Inventors: |
Omori; Hideki; (Chosei,
JP) ; Kabasawa; Takashi; (Chiba, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Omori; Hideki
Kabasawa; Takashi |
Chosei
Chiba |
|
JP
JP |
|
|
Assignee: |
EDWARDS LIMITED
Yachiyo-shi, Chiba 2768523
JP
|
Family ID: |
45927494 |
Appl. No.: |
13/877274 |
Filed: |
July 28, 2011 |
PCT Filed: |
July 28, 2011 |
PCT NO: |
PCT/JP2011/067283 |
371 Date: |
April 1, 2013 |
Current U.S.
Class: |
417/26 |
Current CPC
Class: |
F04D 29/5813 20130101;
F04B 37/085 20130101; F04D 25/068 20130101; F04B 37/08 20130101;
F04D 27/0292 20130101; F04B 37/14 20130101; F04D 19/042
20130101 |
Class at
Publication: |
417/26 |
International
Class: |
F04B 49/00 20060101
F04B049/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 7, 2010 |
JP |
2010-227881 |
Claims
1. A vacuum pump control device for controlling a vacuum pump main
body, the vacuum pump control device comprising: a housing in which
a control circuit for controlling the vacuum pump main body is
disposed; a regenerative resistor storing portion that is provided
in the housing, and has a hollow portion into which is inserted a
regenerative resistor consuming regenerative energy, and a
regenerative resistor fixture for fixing the regenerative resistor;
and a cooling mechanism for cooling the regenerative resistor
storing portion.
2. The vacuum pump control device according to claim 1, wherein the
regenerative resistor storing portion is produced by a casting
process.
3. The vacuum pump control device according to claim 1 or 2,
wherein the regenerative resistor storing portion is positioned
away from a side surface sandwiched between a surface of the
housing on which the control circuit is disposed and a surface of
the housing on which the regenerative resistor storing portion is
provided.
4. The vacuum pump control device according to any one of claims 1
to 3, wherein the regenerative resistor is stored in a regenerative
resistor storing tool having an outer circumferential surface
fitted into an inner circumference of the hollow portion, and is
then inserted into the hollow portion.
5. The vacuum pump control device according to claim 4, wherein
between the inner circumference of the hollow portion and the
regenerative resistor storing tool inserted thereto, a clearance is
provided in advance for accommodating the regenerative resistor
that expands when the regenerative resistor generates heat.
6. A vacuum pump comprising: the vacuum pump main body including a
gas transfer mechanism for transferring a gas from an inlet port to
an outlet port; and the vacuum pump control device according to any
one of claims 1 to 5.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a vacuum pump control
device and a vacuum pump, and particularly relates to a vacuum pump
control device capable of efficiently cooling a regenerative
resistor thereof in order to, for example, prevent a housing of the
vacuum pump control device from overheating, and to a vacuum pump
having this vacuum pump control device.
[0003] 2. Description of the Related Art
[0004] A vacuum pump control device (controller) that controls a
motor for rotating a rotor is electrically connected to a vacuum
pump such as a turbo-molecular pump that performs an exhaust
process by rotating the rotor in a casing with inlet and outlet
ports at high speeds.
[0005] In this type of rotary machine using a motor, electric
energy (regenerative energy) is generated when the motor is rotated
upon deceleration. The regenerative energy increases a DC voltage
in a motor driver circuit controlling the motor, which might lead
to damage to an element inside the circuit. The regenerative
energy, therefore, needs to be processed so that the circuit
element is not damaged. One of the methods for processing
regenerative energy is the use of a regenerative resistor. The
regenerative resistor converts regenerative energy into thermal
energy and consumes this energy. It is, therefore, inevitable that
the regenerative resistor itself generates heat.
[0006] For the purpose of cooling the regenerative resistor, the
regenerative resistor is attached in contact with a side surface
(wall surface) and the like of a housing that encloses elements
configuring the vacuum pump control device. Therefore, the heat is
generated from the section in the housing of the vacuum pump
control device to which the regenerative resistor is attached, and,
consequently, the housing of the vacuum pump control device is
heated. The vacuum pump control device eventually becomes too hot
to touch.
[0007] The tolerance of the regenerative resistor is approximately
300.degree. C., and the regenerative resistor needs to be cooled
constantly so that the regenerative resistor can keep a temperature
significantly lower than the tolerance from the standpoint of
safety and reliability.
[0008] The heat that is generated in the vacuum pump control device
(i.e., the heat generated from the regenerative resistor, etc.) is
transmitted to the vacuum pump through the connection portion
between the vacuum pump control device and the vacuum pump. As a
result, the vacuum pump is heated to a high temperature, harming a
vacuum device connected to the vacuum pump.
[0009] The vacuum device is now described.
[0010] Examples of a vacuum device that keeps a vacuum therein by
performing an exhaust process using a vacuum pump include a
semiconductor manufacturing device, an electron microscope device,
a surface analysis device, and a microfabricated device. In such a
vacuum device, the error between the measurement accuracy and the
machining accuracy becomes significant under the influence of the
radiated heat of the vacuum pump described above, causing a great
deal of problem in the measuring/machining steps.
[0011] For this reason, the regenerative resistor disposed in the
vacuum pump control device needs to be constantly cooled in order
to realize more precise machining or measurement of higher
precision in the vacuum device.
[0012] FIG. 8 is a cross-sectional diagram showing an example of a
schematic configuration of a conventional vacuum pump control
device 2000.
[0013] In this conventional vacuum pump control device 2000, for
example, a heat sink (a radiator, a radiator plate), not shown, is
prepared separately and attached to a heat-generating
machine/electronic component (attached near or on a wall surface
thereof), and the temperature of the vacuum pump control device
2000 is reduced by releasing heat using the heat sink. Further, an
air-cooling fan (cooling fan) 50 and the like are installed as
shown in FIG. 8A, to improve the cooling capacity of the device by
forcibly moving more air therein.
[0014] More specifically, a regenerative resistor 200 is normally
mounted on a motor control board (i.e., a board on which a circuit
for controlling a motor of a vacuum pump is mounted) 300 along with
other elements (a CPU, a transistor, etc.) that also function to
control the motor, as shown in FIG. 8B. However, mounting the
regenerative resistor 200 and the other elements on the same
control board 300 increases the temperatures of both the
regenerative resistor 200 and the other elements due to the heat
generated by the regenerative resistor 200.
[0015] When directly cooling the control board 300 by bringing a
cooling medium close to the control board 300 on which the
regenerative resistor 200 in order to prevent such temperature
increase (in order to cool the regenerative resistor, etc.), dew
condensation forms on the cooled part, causing serious damage to
the other elements.
[0016] The formation of dew condensation here is a phenomenon in
which water vapor in the air condenses and forms liquid droplets on
the cooled surface of the cooled part (i.e., a surface of, or the
inside of, a solid substance) when the cooled part (cooled surface)
is cooled until the dew point or below (i.e., the temperature at
which the relative temperature becomes 100%). When such dew
condensation occurs in the control board 300, there is a
possibility that a malfunction occurs in the control circuit.
[0017] For these reasons, the conventional vacuum pump control
device adopts a method for cooling only the regenerative resistor
200 by removing the regenerative resistor 200 from the control
board 300, bringing the regenerative resistor 200 directly into
close contact with a wall surface of a housing of the vacuum pump
control device 2000, and cooling the wall surface with the cooling
fan 50 as shown in FIG. 8A.
[0018] As an example of bringing an electric element or resistor
into close contact with a wall surface of a housing to cool the
electric element or resistor, Japanese Patent Application
Publication No. 2006-73658 proposes a technology for cooling a
heat-generating element.
[0019] Specifically, Japanese Patent Application Publication No.
2006-73658 discloses a technology for efficiently releasing heat
generated in the electric element, through an electrode and a side
surface portion of an electric element storing container by joining
the electric element to the side surface portion of the electric
element storing container via the electrode.
[0020] However, it is difficult to separately provide a heat sink
in the conventional device, because the vacuum pump is small
relative to the power of the motor or because the surrounding
environment needs to be kept clean, in connection with the steps
carried out in the vacuum device. In most cases, a fan cannot be
installed, in light of noise and reliability.
[0021] In addition, when providing a heat sink or a fan separately,
a dedicated cooling pipe or cooling system are required, which
leads to a cost increase, and moreover a space for disposing these
components needs to be secured.
[0022] When, on the other hand, removing only the regenerative
resistor from the control board and bringing the regenerative
resistor directly into close contact with the wall surface of the
housing of the vacuum pump control device to cool the wall surface,
the temperature of the wall surface of the housing with which the
regenerative resistor is brought into close contact, propagates to
the whole surfaces of the housing. Therefore, the housing itself
becomes too hot to touch, causing dangerous conditions.
SUMMARY OF THE INVENTION
[0023] An object of the present invention, therefore, is to provide
a vacuum pump control device capable of improving heat dissipation
of a regenerative resistor thereof by using a simple configuration,
and a vacuum pump having this vacuum pump control device.
[0024] An invention according to claim 1 provides a vacuum pump
control device for controlling a vacuum pump main body, the vacuum
pump control device including: a housing in which a control circuit
for controlling the vacuum pump main body is disposed; a
regenerative resistor storing portion that is provided in the
housing, and has a hollow portion into which is inserted a
regenerative resistor consuming regenerative energy, and a
regenerative resistor fixture for fixing the regenerative resistor;
and a cooling mechanism for cooling the regenerative resistor
storing portion.
[0025] An invention according to claim 2 provides the vacuum pump
control device described in claim 1, wherein the regenerative
resistor storing portion is produced by a casting process.
[0026] An invention according to claim 3 provides the vacuum pump
control device described in claim 1 or 2, wherein the regenerative
resistor storing portion is positioned away from a side surface
sandwiched between a surface of the housing on which the control
circuit is disposed and a surface of the housing on which the
regenerative resistor storing portion is provided.
[0027] An invention described in claim 4 provides the vacuum pump
control device described in at least one of claims 1 to 3, wherein
the regenerative resistor is stored in a regenerative resistor
storing tool having an outer circumferential surface fitted into an
inner circumference of the hollow portion, and is then inserted
into the hollow portion.
[0028] An invention according to claim 5 provides the vacuum pump
control device described in claim 4, wherein between the inner
circumference of the hollow portion and the regenerative resistor
storing tool inserted thereto, a clearance is provided in advance
for accommodating the regenerative resistor that expands when the
regenerative resistor generates heat.
[0029] An invention according to claim 6 provides a vacuum pump
including: the vacuum pump main body including a gas transfer
mechanism for transferring a gas from an inlet port to an outlet
port; and the vacuum pump control device described in at least one
of claims 1 to 5.
[0030] The present invention can provide a vacuum pump control
device capable of improving heat dissipation of a regenerative
resistor thereof by using a simple configuration, and a vacuum pump
having this vacuum pump control device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a diagram showing an example of a schematic
configuration of a turbo-molecular pump main body that is
integrated with a vacuum pump control device having a heat
dissipation improving casing of a regenerative resistor according
to an embodiment of the present invention;
[0032] FIG. 2 is a diagram showing an example of a schematic
configuration of a turbo-molecular pump main body according to the
embodiment of the present invention;
[0033] FIG. 3 is a cross-sectional diagram of the turbo-molecular
pump main body according to the embodiment of the present
invention, taken along an axis direction;
[0034] FIG. 4 is a diagram showing an example of a schematic
configuration of a vacuum pump control device according to the
embodiment of the present invention;
[0035] FIG. 5A is an enlargement of schematic configurations of a
control unit casing and regenerative resistor casing according to
the embodiment of the present invention; and FIG. 5B is an arrow
view taken along the arrow A of FIG. 5A;
[0036] FIG. 6 is a diagram for explaining the regenerative resistor
according to the embodiment of the present invention;
[0037] FIG. 7 is a diagram showing an example of a metal case for
placing the regenerative resistor therein, the metal case being
used when inserting the regenerative resistor into a regenerative
resistor casing according to a modification of the embodiment of
the present invention;
[0038] FIG. 8 is a diagram showing an example of a schematic
configuration of a conventional vacuum pump control device; and
[0039] FIG. 9 is a diagram showing an example of a connection
between a vacuum pump main body and a vacuum pump control
device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
(i) Brief Summary of an Embodiment
[0040] In an embodiment of the present invention, a regenerative
resistor is provided in a vacuum pump control device (controller)
for controlling a motor rotating a rotor of a vacuum pump and is
stored in an aluminum die-cast casing.
[0041] More concretely, a housing of the vacuum pump control device
is produced by aluminum die casting (metal mold casting), and then
a regenerative resistor storing portion that is provided with a
hollow portion of a size accommodating the entire regenerative
resistor is installed in a part of the aluminum die cast (a top
panel, in the present embodiment, i.e., an upper lid of the vacuum
pump control device). Hereinafter, the regenerative resistor
storing portion with the hollow portion, which is provided in the
aluminum die-cast top panel of the housing of the vacuum pump
control device, is referred to as "casing" for accommodating the
regenerative resistor, the casing being produced by aluminum die
casting.
[0042] The regenerative resistor is removably stored in the hollow
portion, by fitting the regenerative resistor in the hollow portion
and sealing an opening section of the hollow portion with a bolt
and an aluminum sheet (a regenerative resistor fixture) made of the
same material as the casing.
(ii) Detail of the Embodiment
[0043] A preferred embodiment of the present invention is described
hereinafter in detail with reference to FIGS. 1 to 7.
[0044] The present embodiment is described using a turbo-molecular
pump as an example of the vacuum pump.
[0045] In the embodiment according to the present invention, a
vacuum pump control device 20 for controlling a turbo-molecular
pump main body 1 is attached to the turbo-molecular pump main body
1 via pump fixing legs 18. In other words, the turbo-molecular pump
main body 1 is integrated with the vacuum pump control device
20.
(Vacuum Pump Main Body)
[0046] The turbo-molecular pump main body 1 according to the
embodiment of the present invention is described first.
[0047] FIG. 1 is a diagram showing an example of a schematic
configuration of the turbo-molecular pump main body 1 that is
integrated with the vacuum pump control device having the casing
for accommodating the regenerative resistor (referred to as
"regenerative resistor casing," hereinafter) according to the
embodiment of the present invention.
[0048] FIG. 1 also shows a cooling plate (a water-cooling plate) 40
connected to the vacuum pump control device 20 and a part of a
vacuum chamber 30 connected to the turbo-molecular pump main body
1.
[0049] The water-cooling pump 40 is described later.
[0050] The vacuum chamber 30 connected to the turbo-molecular pump
main body 1 is now described.
[0051] The vacuum chamber 30 forms a vacuum device that is used as,
for example, a chamber of a surface analysis device or a
microfabricated device.
[0052] The vacuum chamber 30 is vacuum container configured by a
vacuum chamber wall 31 and has a connection port in order to be
connected to the turbo-molecular pump main body 1.
[0053] A configuration of the turbo-molecular pump main body 1 is
described hereinafter.
[0054] FIG. 2 is a diagram showing an example of a schematic
configuration of the turbo-molecular pump main body 1 according to
the embodiment of the present invention.
[0055] FIG. 3 is a cross-sectional diagram of the turbo-molecular
pump main body 1, taken along an axis direction.
[0056] The turbo-molecular pump main body 1 is a vacuum pump main
body for performing an exhaust process in the vacuum chamber
30.
[0057] The turbo-molecular pump main body 1 is a so-called
composite wing-type molecular pump with a turbo-molecular pump
portion and thread groove pump portion.
[0058] A casing 2 forming an exterior structure of the
turbo-molecular pump main body 1 is in the shape of substantially a
cylinder and configures the housing of the turbo-molecular pump
main body 1 along with a base 3 provided in a lower part (on the
outlet port 6 side) of the casing 2. A gas transfer mechanism,
which is a structure bringing out an exhaust function of the
turbo-molecular pump main body 1, is accommodated in the housing of
the turbo-molecular pump main body 1.
[0059] The gas transfer mechanism is configured mainly by a
rotating portion supported pivotally so as to be able to rotate,
and a fixed portion that is fixed to the housing of the
turbo-molecular pump main body 1.
[0060] An inlet port 4 for introducing a gas to the turbo-molecular
pump main body 1 is formed at an end portion of the casing 2. A
flange portion 5 projecting toward an outer circumference is formed
on an end surface on the inlet port 4 side of the casing 2. The
turbo-molecular pump main body 1 and the vacuum chamber wall 31 are
fixed and bonded to each other with the flange portion 5
therebetween, by using a bolt or other tightening member.
[0061] The outlet port 6 for discharging the gas from the
turbo-molecular pump main body 1 is formed on the base 3.
[0062] Further, a cooling (water-cooling) pipe 70 formed from a
tubular member is embedded in the base 3 in order to reduce the
impact of the heat received by the vacuum pump control device 20
from the turbo-molecular pump main body 1.
[0063] The cooling pipe 70 is a member for cooling the periphery
thereof by letting a coolant, which is a heating medium, flow
inside the cooling pipe 70 and absorbing heat by means of the
coolant.
[0064] The base 3 is forcibly cooled by the coolant flowing in the
cooling pipe 70. As a result, the heat carried from the
turbo-molecular pump main body 1 to the vacuum pump control device
20 can be reduced (suppressed).
[0065] The cooling pipe 70 is configured by a member having low
thermal resistance, which is a member having high thermal
conductivity, such as copper and stainless steel.
[0066] The coolant flowing in the cooling pipe 70, which is a
material for cooling an object, may be liquid or a gas. Examples of
a liquid coolant include water, calcium chloride solution, and
ethylene glycol solution. Examples of a gaseous coolant, on the
other hand, include ammonia, methane, ethane, halogen, helium,
carbon dioxide, and air.
[0067] Note that, in the present embodiment, the cooling pipe 70 is
disposed on the base 3, but the position for placing the cooling
pipe 70 is not limited thereto. For instance, the cooling pipe 70
may be fitted directly into a stator column 10 of the
turbo-molecular pump main body 1.
[0068] The rotating portion is configured by a shaft 7, which is a
rotary shaft, a rotor 8 disposed in the shaft 7, rotor blades 9
provided in the rotor 8, the stator column 10 provided on the
outlet port 6 side (the thread groove pump portion), and the like.
Note that the shaft 7 and the rotor 8 configure a rotor
portion.
[0069] The rotor blades 9 are inclined at a predetermined angle
from a plane perpendicular to the axis of the shaft 7 and expand
radially from the shaft 7.
[0070] The stator column 10 is a cylindrical member disposed
concentrically with a rotary axis of the rotor 8.
[0071] A motor portion 11 for rotating the shaft 7 at high speed is
provided in the vicinity of the middle of an axis direction of the
shaft 7.
[0072] Moreover, radial magnetic bearing devices 12, 13 for
pivotally supporting the shaft 7 in a non-contact state in a radial
direction are provided on the inlet port 4 side and the outlet port
6 side, respectively, with respect to the motor portion 11 of the
shaft 7. Furthermore, an axial magnetic bearing device 14 for
pivotally supporting the shaft 7 in a non-contact state in the axis
direction (axial direction) is provided at a lower end of the shaft
7.
[0073] A fixing portion is formed on the inner circumferential side
of the housing of the turbo-molecular pump main body 1. This fixing
portion is configured by fixed wings 15 provided on the inlet port
side 4 (the turbo-molecular pump portion) and a thread groove
spacer 16 provided on an inner circumferential surface of the
casing 2.
[0074] Each of the fixed wings 15 is configured by a blade that is
inclined at a predetermined angle from a plane perpendicular to the
axis of the shaft 7 and extends from an inner circumferential
surface of the housing of the turbo-molecular pump main body 1
toward the shaft 7.
[0075] The fixed wings 15 on the respective steps are placed apart
from each other by cylindrical spacers 17.
[0076] The turbo-molecular pump main body 1 has a plurality of
steps of the fixed wings 15 arranged alternately with the rotor
blades 9 in the axis direction.
[0077] A spiral groove is formed on a surface of the thread groove
spacer 16 that faces the stator column 10. The thread groove spacer
16 is disposed so as to face an outer circumferential surface of
the stator column 10, with a predetermined amount of clearance
(gap) therebetween. A direction of the spiral groove formed in the
thread groove spacer 16 is directed toward the outlet port 6 when
the gas is transported within the spiral groove in a direction of
rotation of the rotor 8.
[0078] The spiral groove is formed so as to become shallower toward
the outlet port 6. Thus, the gas transported within the spiral
groove is compressed gradually as it approaches the outlet port
6.
[0079] The turbo-molecular pump main body 1 having the
configuration described above performs an evacuation process in the
vacuum chamber 30.
(Vacuum Pump Control Device)
[0080] A structure of the vacuum pump control device 20 that is
attached to the turbo-molecular pump main body 1 having the
above-described configuration is now described.
[0081] FIG. 4A is a diagram showing an example of a schematic
configuration of the vacuum pump control device 20 according to the
embodiment of the present invention.
[0082] The vacuum pump control device 20 according to the present
embodiment configures a control unit that has a control circuit for
controlling various operations of the turbo-molecular pump main
body 1, and is disposed (attached) in a bottom portion of the base
3 of the turbo-molecular pump main body 1 as shown in FIG. 1.
[0083] The vacuum pump control device 20 of the present embodiment
is provided with a connector (not shown) that forms a pair with a
connector (not shown) provided in the turbo-molecular pump main
body 1. The control circuit provided in the vacuum pump control
device 20 is configured to be electrically connected to electronic
components of the turbo-molecular pump main body 1 by joining
(bonding) the connector of the turbo-molecular pump main body 1 and
the connector of the vacuum pump control device 20 to each other.
Accordingly, the vacuum pump control device 20 can not only supply
drive signals or power of the motor portion 11, the radial magnetic
bearing devices 12, 13, the axial magnetic bearing device 14, and a
displacement sensor (not shown) of the turbo-molecular pump main
body 1 to the turbo-molecular pump main body 1, but also receive
various signals from the turbo-molecular pump main body 1, without
using a dedicated cable for connecting the turbo-molecular pump
main body 1 and the vacuum pump control device 20 to each
other.
[0084] The vacuum pump control device 20 according to the
embodiment of the present invention has a vacuum pump control
device housing 220, an upper lid, that is, a control unit casing
210, a regenerative resistor casing 211, a regenerative resistor
200, and a control board 300.
[0085] The vacuum pump control device housing 220 and the control
unit casing 210 are produced by aluminum die casting. The whole or
part of the control unit casing 210 functions as the regenerative
resistor casing 211. The housing 220, the control unit casing 210,
and the regenerative resistor casing 211 are configured by aluminum
die casting.
[0086] The control unit casing 210 is joined to the housing 220 by
a seal member 214 so as to seal an opening of end of an upper part
of the housing 220 (on the turbo-molecular pump main body 1
side).
[0087] The control board 300 has a control circuit mounted thereon.
In the present embodiment, a plurality of the control boards 300
are fixed on the inside of the housing 220.
[0088] The control circuits mounted on the control boards 300 are
now described.
[0089] Each of the control circuits is provided with a drive
circuit, a power supply circuit and the like for the motor portion
11, the radial magnetic bearing devices 12, 13, and the axial
magnetic bearing device 14. In addition, a circuit for controlling
these drive circuits and a storage element for storing various
types of information used for controlling the turbo-molecular pump
main body 1, are mounted on each control circuit.
[0090] Generally, an electronic component (element) used in an
electronic circuit has a set environmental temperature in
consideration of reliability. For instance, the environmental
temperature of the storage element described above is set at
approximately 60.degree. C. Note that such an element of low
heat-resisting property is expressed as "low heat resistant
element."
[0091] During the operation of the turbo-molecular pump main body
1, each of the electronic components must be used within a set
environmental temperature range.
[0092] The circuits provided in the vacuum pump control device 20
use, not only the low heat resistant element described above, but
also a large number of components (power elements) that generate
heat due to loss inside each element (internal loss). For example,
transistor elements that configure an inverter circuit, which is
the drive circuit of the motor portion 11, correspond to these
elements.
[0093] Such elements having a large amount of heat generated
themselves also have set environmental temperatures.
(Cooling Mechanism of the Regenerative Resistor)
[0094] The water-cooling plate 40 is connected to the vacuum pump
control device 20, as shown in FIG. 4A.
[0095] In the water-cooling plate 40, a water-cooling pipe 80,
which is the same as the cooling pipe 70 of the vacuum pump main
body described above (turbo-molecular pump main body 1), is
embedded in the form of a circumference. The water-cooling plate 40
is cooled by a coolant flowing in the cooling pipe 80, and,
consequently, the control unit casing 210 that is in contact with
the water-cooling plate 40 and the regenerative resistor casing 211
that is a part of the control casing 210, are forcibly cooled.
[0096] Furthermore, the water-cooling plate 40 is fixed to a
formation surface of a side wall of the housing 220 by a tightening
member such as a bolt (not shown). In the present embodiment, the
water-cooling plate 40 is configured detachably, i.e., so as to be
able to be easily separated from the vacuum pump control device 20
by removing the bolt (not shown).
(The Regenerative Resistor Casing of the Vacuum Pump Control
Device)
[0097] In the present embodiment, the regenerative resistor casing
211 is disposed in a position away from a side surface of the
vacuum pump control device 20 (a side portion of the housing 220)
by a clearance d, as shown in FIG. 4A. The clearance d is, for
example, approximately 5 mm to 20 m.
[0098] Instead of attaching the regenerative resistor 200 to the
inside of the side surface of the vacuum pump control device 20
(the side portion of the housing 220), the regenerative resistor
200 is positioned away from the side portion of the housing 220, as
described above. Therefore, the section that is likely to be
contacted by a worker performing operations/checkups (the side
portion of the hosing 220) can be prevented from becoming
excessively hot, improving the safety of the operations.
[0099] The present embodiment has the configuration in which the
clearance d is provided between the regenerative resistor casing
211 and the vacuum pump control device 20. However, the present
embodiment is not limited thereto.
[0100] For example, the regenerative resistor casing 211 can be
placed in the center of the control unit casing 210, as shown in
FIG. 4B.
[0101] The regenerative resistor casing 211 can also be configured
by the control unit casing 210 itself, as shown in FIG. 4C.
[0102] Due to the configuration described above in which the
regenerative resistor 200 is stored in the aluminum die-cast casing
(the regenerative resistor casing 211) larger than the regenerative
resistor 200, the heat capacity increases more than when the
regenerative resistor 200 is disposed alone. Therefore, an increase
in temperature of the regenerative resistor 200 itself can be
prevented.
[0103] If the regenerative resistor 200 generates heat when it is
disposed alone, there is a risk that the temperature of the
regenerative resistor 200 increases to 200 to 300.degree. C.,
exceeding an allowable temperature (which is generally set at
approximately 300.degree. C.) thereof. However, storing the
regenerative resistor 200 in the container (aluminum die-cast
casing) can make it difficult for the temperature of the
regenerative resistor 200 to increase for the reasons mentioned
above. The experiment has succeeded in lowering the temperature to
approximately 150.degree. C., which is not an issue for the
allowable temperature.
[0104] FIG. 5A is an enlargement of schematic configurations of the
control unit casing 210 and regenerative resistor casing 211
according to the embodiment of the present invention. FIG. 5B is an
arrow view taken along the arrow A of FIG. 5A.
[0105] The regenerative resistor casing 211 according to the
embodiment of the present invention is configured as a part of the
control unit casing 210 (aluminum die-cast casing) that plays the
role of the upper lid (top panel) of the vacuum pump control device
20.
[0106] In the present embodiment the regenerative resistor casing
211 is a part of the control unit casing 210; however, the present
embodiment is not limited to this configuration. For example, the
regenerative resistor casing 211 produced separately by aluminum
die casting (metal mold casting) can be attached to the control
unit casing 210 by an attachment tool (e.g., a bolt, etc.).
[0107] The regenerative resistor casing 211 has a hollow portion
212 of a size accommodating the entire regenerative resistor 200.
The regenerative resistor 200 is inserted and fitted into this
hollow portion 212.
[0108] The regenerative resistor casing 211 further has a
regenerative resistor fixture 213 that functions as a lid for
closing (sealing) the hollow portion 212 in order to prevent the
fitted regenerative resistor 200 from falling, and a bolt 215 that
is an attachment tool for attaching the regenerative resistor
fixture 213 to the regenerative resistor casing 211 after the
regenerative resistor 200 is fitted in the regenerative resistor
casing 211. With these components provided in the regenerative
resistor casing 211, the regenerative resistor 200 can removably be
supported fixedly (stored).
[0109] The regenerative resistor 200 is connected to the control
board 300 (FIG. 4) by a conductor wire 250.
[0110] In order to increase the heat capacity, the regenerative
resistor casing 211 of the present embodiment is in the shape of a
cylinder (column) with a rectangular cross-sectional shape and an
oval bottom shape (a barrel shape, an egg shape) (when viewed in
the direction of the arrow A), as shown in FIG. 5. However, the
shape of the regenerative resistor casing 211 is not limited
thereto.
[0111] In order to be able to insert the regenerative resistor 200,
the lateral area of an inner surface of the hollow portion 212 of
the regenerative resistor casing 211 is made greater than that of
an outer surface (outer circumference) of the regenerative resistor
200.
[0112] More specifically, a clearance is provided to accommodate
the regenerative resistor 200 that expands when the regenerative
resistor 200 generates heat. This clearance is a space of
approximately 12 to 38 .mu.m.
[0113] With the appropriate size of clearance provided in advance,
the regenerative resistor 200, which expands when the regenerative
resistor 200 generates heat, can be supported fixedly (stored) in
the regenerative resistor casing 211, tightly with no space
therebetween (in an adhered state).
[0114] Although the hollow portion 212 and the regenerative
resistor 200 to be inserted therein are slightly separated from
each other at the time of the insertion of the regenerative
resistor 200, the space (clearance) between regenerative resistor
200 and the regenerative resistor casing 211 becomes eliminated as
the regenerative resistor 200 generates heat and expands when the
vacuum pump control device 20 is driven (i.e., when the
regenerative resistor 200 needs to be cooled). Thus, the
regenerative resistor 200 can be kept in a contact state with the
regenerative resistor casing 211 at all times. Therefore, the
regenerative resistor 200 can constantly be cooled efficiently by
the water-cooling plate 40 (FIG. 4) disposed in the upper part of
the regenerative resistor casing 211 (i.e., on the turbo-molecular
pump main body 1 side).
[0115] In the present embodiment, because the regenerative resistor
200 and the regenerative resistor casing 211 are in close contact
with each other as described above, the water-cooling plate 40 can
directly cool the regenerative resistor 200 via the regenerative
resistor casing 211 (in other words, there is no air
therebetween).
[0116] Moreover, according to the present embodiment having such a
configuration, the area of contact between the regenerative
resistor 200 and the regenerative resistor casing 211 (the area
where the regenerative resistor 200 and the regenerative resistor
casing 211 are brought into close contact with each other) is
significantly greater that of the conventional configuration (FIG.
8C) in which the regenerative resistor 200 and the side portion of
the housing 220 to which the regenerative resistor 200 is attached
are in line contact with each other (when the regenerative resistor
is in the shape of a cylinder) or in surface contact (one surface)
(when the regenerative resistor is in a rectangular shape).
[0117] Therefore, the cooling effect of the water-cooling plate 40
can be exercised extensively over a side circumferential surface of
the regenerative resistor 200. As a result, the cooling effect can
be improved.
[0118] The turbo-molecular pump main body 1 and the vacuum pump
control device 20 are integrated with each other in the present
embodiment; however, the present embodiment is not limited to this
configuration.
[0119] For example, when the vacuum pump main body (turbo-molecular
pump main body) and the vacuum pump control device are not
integrated with each other as shown in FIG. 9, the vacuum pump main
body and the vacuum pump control device may be connected with each
other by a cable and then disposed. In this case, a cooling system
(a water-cooling pipe, etc.) for use in a cooling plate used in the
vacuum pump control device may be provided separately, and water
required for cooling may be prepared (supplied) thereto.
(The Regenerative Resistor)
[0120] FIGS. 6A to 6C are diagrams for explaining the regenerative
resistor.
[0121] The regenerative resistor 200 is in various shapes. In the
present embodiment, the regenerative resistor 200 is in the shape
of a cylinder or column (cylindrical rod); however, the shape of
the regenerative resistor 200 is not limited thereto. For example,
a columnar shape with a square, hexagonal, or rectangular bottom
shape can be considered as the shape of the regenerative
resistor.
(Modification)
[0122] The embodiment of the present invention described above can
be modified in various forms.
[0123] FIG. 7 is a diagram showing an example of a metal case 400,
which is a regenerative resistor storing tool for storing the
regenerative resistor 200 and used when inserting the regenerative
resistor 200 into the regenerative resistor casing 211 according to
a modification of the embodiment of the present invention.
[0124] The shape or size of a ready-made regenerative resistor 200
is normally various and inconsistent, as shown in FIGS. 6A to 6C.
The surface of such a regenerative resistor 200 is not a smooth
flat surface. For this reason, when directly inserting the
regenerative resistor 200 into the regenerative resistor casing
211, only a certain part of the regenerative resistor 200 comes
into contact with an inner wall surface of the regenerative
resistor casing 211.
[0125] The present modification deals with such various
shapes/sizes and non-smooth surface of the regenerative resistor
200, by placing the regenerative resistor 200 in the metal case 400
for exclusive use for a regenerative resistor, instead of directly
inserting the regenerative resistor 200 into the regenerative
resistor casing 211, and then inserting (storing) this metal case
400 into the regenerative resistor casing 211. The cooling effect
is further enhanced by pouring electrothermal grease of high
thermal conductivity around the regenerative resistor 200 in the
metal case 400 to narrow the space therebetween. As the metal case
for exclusive use for a regenerative resistor, a rectangular metal
case 400 is used when the regenerative resistor 200 is in a
rectangular shape as shown in FIGS. 6A and 6B, or a cylindrical
metal case 400 is used when the regenerative resistor 200 is in a
cylindrical shape as shown in FIG. 6C.
[0126] This metal case 400 is shaped such that an outer
circumference thereof extends along the inner circumferential
surface of the regenerative resistor casing (i.e., the hollow
portion). Therefore, the metal case 400 can be fitted in the
regenerative resistor casing 211, with no space therebetween.
[0127] The configuration in which the regenerative resistor 200 in
the metal case 400 of high form/dimensional accuracy is inserted
into the regenerative resistor casing 211, can reduce the form
error between the regenerative resistor casing 211 and the metal
case 400 and equalize the dimensional difference therebetween.
[0128] Provision of the metal case 400 makes it possible for the
regenerative resistor 200 to come into close contact with the
inside of the metal case 400 when generating heat and thereby
expanding. As a result, the regenerative resistor 200 can come into
close contact with the regenerative resistor casing 211 (via the
metal case 400) that is in close contact with the outside of the
metal case 400.
[0129] It is desired that the metal case 400 be made of
heat-resistant steel or stainless steel (SUS) that give thermal
resistance.
[0130] This is because, if the metal case 400 is prepared with
aluminum, which is the same material as the regenerative resistor
casing 211 that is an aluminum die-cast casing, the heat of the
regenerative resistor 200 might causes fusion between the metal
case 400 and the regenerative resistor casing 211.
[0131] Fusion therebetween makes it difficult or impossible to
remove the regenerative resistor 200 from the regenerative resistor
casing 211 when, for example, replacing the regenerative resistor
200.
[0132] In the configuration in which the metal case 400 conforming
to the shape of the regenerative resistor 200 is used, even if the
expanded regenerative resistor 200 cannot come into close contact
with the regenerative resistor casing 211, the interior of the
metal case 400 can be machined in accordance with the regenerative
resistor 200 (i.e., such that the expanded regenerative resistor
200 can come into close contact with the metal case 400), so that
the regenerative resistor casing 211 does not have to be machined.
As a result, the production costs can be reduced.
[0133] In a modification of the regenerative resistor 200, a
regenerative resistor may be made to order, by installing a
resistor in the metal case 400 and then encasing the resistor in
ceramic or alumina oxide.
[0134] According to the embodiment and modification of the present
invention described above, (1) to (5) described hereinafter can be
realized.
[0135] (1) The whole or part of the top panel of the vacuum pump
control device is provided with the aluminum die-cast regenerative
resistor casing for exclusive use for a regenerative resistor.
Therefore, a higher heat capacity can be obtained compared to when
the regenerative resistor is disposed alone, making it difficult
for the temperature of the regenerative resistor itself to
increase.
[0136] In other words, the regenerative resistor does not generate
heat to high temperature by itself. Instead, the heat of the
regenerative resistor is transmitted to the regenerative resistor
casing that plays the role of accumulating heat. Accordingly, the
heat capacity can be increased more than when the regenerative
resistor is disposed alone.
[0137] As a result, a vacuum pump control device capable of
inhibiting the temperature increase and a vacuum pump having such a
vacuum pump control device can be provided.
[0138] (2) The cooling (water-cooling) plate is provided on the top
panel (i.e., the control unit casing) of the vacuum pump control
device having the regenerative resistor casing. Therefore, the heat
radiated from the regenerative resistor can be blocked in the
vicinity of the top panel of the vacuum pump control device. This
can not only reduce (attenuate) the temperature increase in the
vacuum pump control device main body but also reduce the amount of
heat that is radiated from the regenerative resistor to the inside
of the turbo-molecular pump integrated with the vacuum pump control
device.
[0139] As a result, a vacuum pump control device capable of
improving heat dissipation of a regenerative resistor thereof by
using a simple configuration and capable of appropriately
preventing a temperature increase, and a vacuum pump having this
vacuum pump control device, can be provided.
[0140] (3) A hole (hollow) for accommodating the entire
regenerative resistor is provided in the regenerative resistor
casing. The hole is designed to conform to the shape of the
regenerative resistor, in other words, designed to have a size that
allows the regenerative resistor and the regenerative resistor
casing to come into close contact with each other when the
regenerative resistor generates heat and expands. Moreover, the
regenerative resistor is inserted into this hole, thereby closing
the opening of the hole. This configuration can enhance the
adherence between the regenerative resistor casing and the
regenerative resistor, improving the thermal conductivity.
[0141] As a result, a vacuum pump control device capable of
improving heat dissipation of a regenerative resistor thereof, and
a vacuum pump having this vacuum pump control device, can be
provided.
[0142] (4) The regenerative resistor casing is installed in a
position away from the side wall of the housing of the vacuum pump
control device by a predetermined amount of clearance, in the
vacuum pup control device. Therefore, a temperature increase of the
wall surface of the vacuum pump control device can appropriately be
suppressed, improving the safety when a person touches the outside
of the vacuum pump control device.
[0143] (5) The regenerative resistor is placed in the metal case
for exclusive use for a regenerative resistor, and then this metal
case is inserted into (stored in) the regenerative resistor casing,
the metal case conforming to the shape of the inner circumferential
surface of the regenerative resistor casing. This configuration,
therefore, can bring the regenerative resistor casing and the
regenerative resistor into close contact with each other,
regardless of the various different shapes/sizes and non-smooth
surface of the regenerative resistor main body.
[0144] As a result, even when using regenerative resistors of
different types, metal cases corresponding to the types can be
used. Therefore, a vacuum pump control device capable of uniformly
improving heat dissipation of the corresponding regenerative
resistor, and a vacuum pump having this vacuum pump control device,
can be provided.
EXPLANATION OF REFERENCE NUMERALS
[0145] 1 Turbo-molecular pump main body
[0146] 2 Casing
[0147] 3 Base
[0148] 4 Inlet port
[0149] 5 Flange portion
[0150] 6 Outlet port
[0151] 7 Shaft
[0152] 8 Rotor
[0153] 9 Rotor blade
[0154] 10 Stator column
[0155] 11 Motor portion
[0156] 12, 13 Radial magnetic bearing device
[0157] 14 Axial magnetic bearing device
[0158] 15 Fixed wing
[0159] 16 Thread groove spacer
[0160] 17 Spacer
[0161] 18 Pump fixing leg
[0162] 20 Vacuum pump control device
[0163] 30 Vacuum chamber
[0164] 31 Vacuum chamber wall
[0165] 40 Water-cooling plate
[0166] 50 Air-cooling fan
[0167] 70 Cooling pipe
[0168] 80 Cooling pipe
[0169] 200 Regenerative resistor
[0170] 210 Control unit casing
[0171] 211 Regenerative resistor casing
[0172] 212 Hollow portion
[0173] 213 Regenerative resistor fixture
[0174] 214 Seal member
[0175] 215 Fixing bolt
[0176] 220 Housing
[0177] 250 Conductor wire
[0178] 300 Control board
[0179] 400 Metal case
[0180] 2000 Vacuum pump control device
* * * * *