Electrical generator or motor structure – Dynamoelectric – Linear
Reexamination Certificate
2002-04-05
2003-04-22
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Linear
C310S012060, C310S090000, C074S496000, C355S053000, C430S022000, C378S034000
Reexamination Certificate
active
06552449
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a stage system with onboard linear motor to provide a position controller energized with a linear motor, which has been extensively used in fields as diverse as semiconductor industries, industrial robots, inspection equipments, machine tools, and so on.
2. Description of the Prior Art
A slider unit with onboard linear motor made compact or slim in construction is disclosed in Japanese Patent Laid-Open No. 266659/1997, in which a small linear-motor table system is made to propel any one of confronting bed and table relatively to another. A solenoid-energized linear actuator is installed between the bed and the table, at least any one of which serves for a yoke of the solenoid-energized linear actuator, thus allowing the linear-motor table system to be made slim in size and in expensive in production cost.
Disclosed in Japanese Patent Laid-Open No. 266660/1997 is an X-Y table system that adopts a solenoid-energized linear actuator to be made compact or slim in construction. With the X-Y table cited earlier, all of a power line for the solenoid-energized linear actuator and wires for taking out signals from various sensors are held together on an intermediate moving member of X-table and assembled into a single cord that will be connected to any outside control unit. This arrangement helps lessen any potential negative affection that might be otherwise caused by the wires and realize well the high speed, durability, less occurrence of debris and overall shrinkage in size.
Moreover, a slider unit constructed as illustrated in
FIG. 12
has already been developed and disclosed in the co-pending senior application that was opened under Japanese Patent Laid-Open No. 352744/2001. The slider unit has an onboard moving-magnet linear motor and is envisaged improving high-speed operation and much response ability of the movable table
60
relatively to the stationary bed
64
and also realizing much more accurate position control of the table
60
to the bed
64
. With the slider unit, the three-phase conduction system is adopted for conduction to any armature winding
65
while the driving circuit is removed to any outside driver. This design can provide the bed
64
that is made simple in construction and also reduced in height. The stationary bed
64
in the slider unit is made of magnetic material while the movable table
60
is also made of magnetic material and arranged for sliding movement with respect to the bed
64
through a linear motion guide unit
61
that is mainly comprised of a slider
62
and a track rail
63
. The movable table
60
has mounted thereon with a field magnet
66
on which magnetic poles are arranged in such a way that they alternate in polarity along a traveling direction of the table
60
, while the bed
64
has the armature windings
65
on a surface of the bed
64
, which is in opposition to the field magnet
66
. In addition, there is provided a position detector composed of a linear scale
68
and a sensor
67
to determine the position of the table
60
with respect to the bed
64
in the traveling direction of the table
60
.
Moreover referring to
FIG. 13
, there is shown a prior rotary table system in which a servo-actuator is connected directly to a motor
81
in direct-drive manner to accomplish the very fast, highly accurate position control in turning direction with no backlash or no lost motion. The servo-actuator to control an angular position of a table
70
with high speed is mainly comprised of the motor
81
, an optical encoder
78
and a rolling-contact bearing
72
. The motor
81
is comprised of a rotor core
77
fixed to the table
70
, and a stator core
76
mounted on a housing
71
. With the rotary table system stated earlier, the table
70
is encased in the housing
71
for free rotation through the rolling-contact bearing
72
that is composed of an inner ring
74
, an outer ring
73
and rollers
76
. The rolling-contact bearing
72
is constructed with a crossed-roller bearing in which the rollers
75
are arranged circumferentially with their axes intersecting alternately one another in such a manner that each roller can carry the table
70
against any load in every direction, either radial or axial.
By the way, the table-position control system or the stage system used commonly for various machines such as semiconductor fabricating equipments is to move the work such as a semiconductor stock and the like, which is mounted on the movable table, in any one or both of X-direction and Y-direction perpendicular to the X-direction, and/or turn the work over an angle &thgr; thereby transferring the work to any desired position. To keep the workroom environment clean, the linear motors have been extensively employed for the driving means to move the table or the stage, whether linear or angular. Recently the systems that are used to manufacture the semiconductors are legion, and the semiconductor industries, image processors, inspection instruments or the like further need the position controls of high accuracy, even with compactness and inexpensiveness.
With the rotary table system as shown in
FIG. 13
, nevertheless, the rotor core
77
of the motor
81
is arranged overall around the periphery of the table
70
while the stator core
76
is installed circumferentially in an annular groove in the housing
71
in opposition to the rotor core
77
. This type of the prior rotary table system results in becoming tall in height and a corresponding increase in dimensions, and also would get complicated in construction itself. The prior stage system as stated earlier and shown in
FIG. 12
uses the linear motor, but only to propel the table in linear direction through the linear motion guide unit, not to provide position controls in a circular or angular direction. Thus, it remains a major challenge to provide a stage system that will be allowed to not only travel in linear direction, but also provide accurate position control in circular direction or in angular &thgr; direction by the use of some linear motors, which are substantially identical to one another in construction to reduce the desired parts and members making up the stage system in their numbers, thereby helping make the stage system smaller in dimensions, lighter in weight, even with better in response ability than the same sort of prior table system ever developed.
SUMMARY OF THE INVENTION
It is the primary object of the present invention to overcome the major problem as described just above and to provide a stage system with onboard linear motor, which is constructed to allow position control of tiny angles in either direction of turning or in &thgr; direction. Still more particular object of the present invention is to provide a stage system with onboard linear motor, which may afford a moving table high-precision angular-position control and better response ability, even being made thin and small in dimensions, light in weight and compact or slim in construction.
The present invention is concerned with a stage system with onboard linear motor, comprising an anti-turning stage kept against rotation, a turning stage lying on the anti-turning stage for rotation relatively to the anti-turning stage, a rolling bearing means interposed between the anti-turning stage and the turning stage to support the turning stage for free rotation, and a turning linear motor for driving the turning stage over a tiny amount of angle in either direction of rotation, wherein the turning linear motor is comprised of a primary side of more than one armature winding arranged in juxtaposition in straight line on either one of the turning stage and the anti-turning stage, and a secondary side of field magnets arranged in juxtaposition in opposition to the armature winding on another of the turning stage and the anti-turning stage, with magnetic poles alternating in polarity in straight line.
In an aspect of the present invention, there is provided a stage system with onboard linear motor, in which the turning
Ohno Masaki
Tsuboi Takaaki
Browdy and Neimark , P.L.L.C.
Mohandesi Iraj A.
Nippon Thompson Co. Ltd.
Ramirez Nestor
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