Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-10-02
2003-06-03
Lam, Thanh (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S180000, C310S013000
Reexamination Certificate
active
06573630
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to an electromagnetic actuator and, more particularly, to a comparably small sized electromagnetic actuator using for such as automotive vehicle, for driving a reflecting mirror of a radar, for example.
2. Background Art
FIG. 8 and 9
are the schematic views showing an actuator according to a prior art. More in detail,
FIG. 8
is the actuator classified as a voice coil type using a pair of the electromagnetic driving elements. Each of the electromagnetic driving elements consists of a magnet
2
installed on a bottom surface of a fixed cylindrical core
1
, a bar shaped core
3
set on the magnet
2
, a movable coil
4
installed in a ring shaped gap formed between the bar shaped core
3
and the cylindrical core
1
and a driven member
5
connected with the moving coil
4
. The driven member
5
is installed free of rotation centering a rotating axis
7
supported by a bearing
6
and is driven by the movable coil
4
.
In the actuator of the voice coil type, the driven member
5
is able to be driven in a direction of up and down by a driving force generated perpendicular to the movable coil according to a direction and a magnitude of a current through the movable coil
4
. However, there are some disadvantages in using the movable coil
4
as depicted in the following. For example, a wiring
4
a
to the moving coil
4
is necessary, and, moreover, the moving coil
4
is needed to be light in weight for high speed operation. Accordingly, some constraints arise such as in increasing a number of turns or in enlarging a wire diameter of the movable coil
4
, and so an adequate magnetic flux by the movable coil
4
is hard to be obtained. To cope with these problems, strengthening a force of the magnet
2
, and reducing a magnetic resistance of the cylindrical core
1
and making the ring shaped gap smaller between the movable coil
4
and the cylindrical core
1
are inevitable for enlarging an electromagnetic driving force of the electromagnetic driving element. Resultantly, a high accuracy in fabricating the electromagnetic driving element becomes absolutely necessary.
FIG. 9
is an actuator classified as a solenoid type using a pair of the electromagnetic driving elements. Each of the electromagnetic driving elements consists of a fixed cylindrical coil
8
installed inside of the cylindrical core
1
and a movable core
9
fixed to the driven member
5
, wherein the movable core
9
is installed to be attracted into the inside of the fixed coil
8
. As above explained, although the actuator of the solenoid type is structurally simple, it has some weak points in a high speed control of the driven member
5
wherein a driving direction of the movable core
9
is limited to an attracting direction by the fixed coil
8
, and a weight of a moving part is heavy due to the movable core
9
.
SUMMARY OF THE INVENTION
In view of the above, it is the object of the present invention to provide an electromagnetic actuator wherein a driving force for a movable component fixed to a driven member is continuously controlled by a control coil fixed to a fixed component, a weight of the movable component is smaller and a high fabricating accuracy becomes is not required.
An electromagnetic actuator according to the present invention is equipped with, at least, an electromagnetic driving element for driving a driven member,
said electromagnetic driving element comprises a movable component fixed to the driven member and a fixed component facing said movable component,
said movable component includes a movable magnet with the first magnetic pole of the first magnetic polarity and the second magnetic pole of the second magnetic polarity,
said fixed component includes a fixed magnet with the first magnetic pole of the first magnetic polarity and the second magnetic pole of the second magnetic polarity installed wherein the first magnetic pole of the fixed magnet opposes to the first magnetic pole of said movable magnet so as to give an electromagnetic repulsive force to said movable magnet,
said fixed component also includes a control coil for generating an electromagnetic controlling force according to an exciting current, said control coil is installed between the first magnetic pole of said fixed magnet and the first magnetic pole of said movable magnet,
wherein said movable magnet is controlled by a totalized electromagnetic force of said electromagnetic repulsive force and said electromagnetic controlling force.
According to the electromagnetic actuator, as the movable magnet of the movable component is driven by the totalized electromagnetic force of the electromagnetic repulsive force by the fixed magnet of the fixed component and the electromagnetic controlling force by the control coil of the fixed component, the totalized electromagnetic force for the movable magnet is possible to be controlled continuously by the control coil. Moreover, as the driving force is adequately obtained by increasing the number of turns and enlarging the wire diameter of the control coil which is installed to the fixed component, a cutoff in weight of the movable magnet is possibly and a high fabricating accuracy of the fixed component becomes unnecessary.
The electromagnetic actuator according to the present invention has a configuration, wherein the control coil is installed between the first magnetic pole of said fixed magnet and the first magnetic pole of said movable magnet, apart both from the first magnetic poles of said fixed magnet and said movable magnet.
According to this configuration, as the control coil is installed between the first magnetic pole of the fixed magnet and the first magnetic pole of the movable magnet apart from the first magnetic poles of both magnets, a decrease in a magnetism keeping ability of the fixed magnet due to a magnetic flux of the control coil is mitigated and the electromagnetic repulsive force can be adequately given from the fixed magnet to the movable magnet.
Furthermore, the electromagnetic actuator according to the present invention has a configuration, wherein a plate of a magnetic material is disposed on the second magnetic pole of said fixed magnet.
According to this configuration, as the second magnetic pole of the fixed magnet is installed to a plate made of a magnetic material, a magnetic coupling is strengthened both between the fixed magnet and the movable magnet and between the control coil and the movable magnet, leading to give the electromagnetic repulsive force and the electromagnetic controlling force to the movable magnet to a larger extent.
Furthermore, the electromagnetic actuator according to the present invention has a configuration, wherein the control coil is turned around a center line between the first magnetic pole of said fixed magnet and the first magnetic pole of said movable magnet.
Furthermore, the electromagnetic actuator according to the present invention has a configuration, wherein a control core is installed between the first magnetic poles of said fixed magnet and the movable magnet, and said control coil is turned around said control core.
According to these configuration, as the control coil is turned around a center line between the first poles of the fixed magnet and the movable magnet, or the control coil is turned around the control core installed between the first magnetic poles of the movable magnet and the fixed magnet, the magnetic flux by the control coil is more effectively given to the movable magnet, leading to give the electromagnetic controlling force to a larger extent.
Furthermore, the electromagnetic actuator according to the present invention has a configuration, wherein one end of said control core is installed opposing to the first magnetic pole of the movable magnet through a gap, and the other gap is formed between the opposite end of said control core and the first magnetic pole of said fixed magnet.
According to this configuration, as one end of the control core opposing to the first magnetic pole of the movable magnet throu
Lam Thanh
Sughrue & Mion, PLLC
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