Inductor devices – Windings
Reexamination Certificate
2002-03-26
2003-11-11
Mai, Anh (Department: 2832)
Inductor devices
Windings
C336S224000, C336S223000
Reexamination Certificate
active
06646536
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a single coil and its winding former of a coil unit for a linear motor.
2. Description of the Related Art
A linear motor has a simple structure, comprises a small number of parts, and drives a moving body linearly, and its drive is precise and quick. It is widely applied to linear driving devices and positioning devices in all fields such as exposing devices for manufacturing semiconductors, and highly precise machine tools.
The linear motor generally comprises a magnetic pole unit including magnets, and a coil unit including coils, one of them is fixed to a base as a fixed body, and the other of them is connected to a moving table or the like as a moving body. The magnetic pole unit and the coil unit are placed opposing to each other at a certain gap. When a magnetic force is generated between them, the magnetic force as a thrust force drives the moving body without contact while the gap is being maintained.
A multi-pole/multi-phase DC linear motor is disclosed as one form of the linear motor. A magnetic pole unit is formed such that multiple N/S poles are placed such that neighboring poles have different polarities in this linear motor. One coil unit is formed such that multiple single coils are wired with one another as a whole.
The individual single coils constituting the coil unit have an approximately rectangular ring-like shape altogether. Two sides of the four sides of this rectangle, which oppose to each other, and are orthogonal to a moving direction, function as a pair of effective conductors contributing to generating a thrust force for a moving body of a linear motor. The other two sides opposing to each other form a pair of connecting conductors for connecting between the effective conductors, and do not contribute to generating the thrust force of the linear motor.
The thrust force F (N) of the linear motor is represented as: F=BIL where B (T) is a magnetic flux density acting on the effective conductors, I (A) is an electric current flowing thorough the effective conductors, and L (m) is the length of the effective conductors. When the number of turns of the single coil is n, F is represented as: F=BniL where i is a current per conductive wire.
Thus, it is necessary to increase the number of the turns n of the single coil for securing as large the thrust force F as possible with predetermined dimensions, or with predetermined various types of specifications of constituting members.
Because not only the area of the transverse section of the effective conductors, but also that of the connecting conductors increases as the number of turns n increases, a storage of the individual single coils becomes a problem when the multiple single coils are connected to form a coil unit.
Because the effective conductors of the individual single coils of the coil unit used for the linear motor are arranged closely to one another in a traveling direction, and the connecting conductors of the individual single coils take up spaces, it is important how to treat the connecting conductors, and then how to arrange multiple singe coils consecutively.
For example, parts close to the ends of effective conductors are bent from a coil plane (a plane including axial centers of the effective conductors) on a single coil, and three types of the single coils different in the degree of the bend are provided in the U.S. Pat. No. Re 34,674. Namely, three types of the single coils which are different in an offset of the connecting conductors from the coil plane are provided, and are sequentially arranged in a traveling direction for providing a constitution for closely arranging the effective conductors of the individual single coils while preventing interference between the connecting conductors.
However, because this constitution requires three types of single coils in consequence, the constitution has problems that the manufacturing cost increases, and the three types of connecting conductors occupy unique traveling spaces (projected areas on a section transverse to the traveling direction) respectively, thereby extremely increasing spaces around the connecting conductors as a whole.
Especially, when the number of turns of the coil n increases for increasing the transverse section of the effective conductors, thereby increasing a thrust force (a drive capability) of the motor, the transverse section of the connecting conductors increases accordingly, the space occupied by the connecting conductors becomes extremely large, and it is impossible to design a motor for increasing its space efficiency.
Also, when the entire coil unit is stored in a sealed container for cooling to avoid an effect of generated heat from the coil unit, for example, if the space occupied by the connecting conductors increases, a design for placing the magnet unit with maintaining a proper gap to the effective conductors becomes difficult while the coil unit is being stored in the sealed container.
In view of the foregoing, the inventors have proposed a single coil for a linear motor which improves these defects, and a coil unit using the same single coils in Japanese Patent Laid Open No. 2001-67955. The following section briefly describes the art because it helps understanding the problems to be solved by the present invention, and the validity of the present invention properly.
Multiple coil seats
3
shown in (a) of
FIG. 8
are piled while the size is being changed gradually, a single coil
2
is formed such that ends of effective conductors
4
together with connecting conductors
6
are bent largely at an approximately right angle with respect to a coil plane CP, and the resultant single coil
2
in a saddle-like shape is used in this art as shown in (b). Single coils
2
a
whose connecting conductors
6
are bent toward right, and single coils
2
b
whose connecting conductors
6
are bent toward left with respect to a traveling direction A are alternately inserted into companion effective conductors
4
a
and
4
b
, and they are arranged closely and orderly with almost no gaps as shown in (c) of the FIG.
8
. The individual single coils
2
are wired with one another according to specifications of a coil unit
10
to form the single coil unit for one linear motor.
When the single coils
2
are driven with a three-phase current, the phases of the current for the neighboring single coils
2
are shifted to one another by 120 degrees, and a three-phase coil unit with U, V, and W phases is formed. One pole, which is a constituting unit of a linear motor is defined as a part from one N/S pole to a next N/S pole in a magnet arrangement. The number of the corresponding single coils
2
(per pole) is three, and they consist of the single coils
2
for the U, V, and W phases.
Commercially available conventional coil units for linear motors including one according to the U.S. Pat. No. Re 34, 674 are formed by combining three types of single coils different in a form of connecting conductors bent toward left or right with respect to a traveling direction as a base, and has a characteristic that coil sections corresponding to three phases appear in a section perpendicular to the traveling direction (coinciding with a direction A). This means that the projected area in the transverse section in the traveling direction has an area corresponding at least three of the transverse sections of the connecting conductors.
On the other hand, the coil unit
10
relating to Japanese Patent Laid Open No. 2001-67955 includes only one type of the single coils
2
, and they are simply oriented toward left or right, and combined with one another to form the coil unit
10
. Thus, the coil unit
10
has a remarkable feature that the coil sections corresponding to only two phases appear in a section view of the coil unit
10
. This means that projected area in the transverse section in the traveling direction basically has an area corresponding to only the two transverse sections of the connecting conductors.
In addition, the single coil
2
and
Koyanagawa Yasushi
Mori Hidehiko
Arent Fox Kintner Plotkin & Kahn
Mai Anh
Sumitomo Heavy Industrie's, Ltd.
LandOfFree
Single coil of coil unit for linear motor and winding former... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Single coil of coil unit for linear motor and winding former..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Single coil of coil unit for linear motor and winding former... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3163318