Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-07-16
2003-09-30
Le, Dang (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310SDIG006
Reexamination Certificate
active
06628038
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a small-sized and thin type resolver using a sheet coil, which is used for detection of speed and position of a servomotor in the field of, for example, factory automation equipment and office automation apparatuses, and is composed of a sheet coil.
2. Description of the Related Art
A prior art with resolver using a sheet coil is such that a flat sheet coil of an excitation phase consisting of one phase and a flat sheet coil of a detection phase consisting of two phases are disposed with air gaps, wherein the detection phase has a detection phase of eddy current patterns made of copper foil and formed on the surface side and rear side thereof, between which a thin film insulation sheet layer is placed, and another detection phase having a phase difference of an electric angle of 90° with respect to the above-described detection phase, although it is the same pattern, between which the thin insulation sheet layer is placed. On the other hand, the excitation phase is such that the same eddy-like pattern is disposed without any difference in phase on the surface side and rear side thereof, between which a thin-film insulation sheet layer is placed. The resolver using a sheet coil is such that the flux linkage of the detection changes according to a sine wave by a rotation angle at high precision on the basis of an eddy pattern that is accurately patterned by etching, etc., and the angular error is reduced to be small (For example, JP, 8-84449, A).
Also, the following rotary transformer is disclosed as that having the same functions as those of the resolver using a sheet coil. In the rotary transformer, a pair of secondary side conductor patterns formed on the surface side and rear side of a thin-film substrate made of an insulation body are formed of multi-layered thin-film conductors concentrically with clearance secured at a part of a circle, and the ends between the thin-film conductors are connected to each other by a jumper line, wherein the second side is opposed to and disposed at the primary side of the transformer through a throughhole and clearance (For example, JP, 8-306562, A).
Also, in other prior art with resolvers having a sheet coil, there is a resolver in which a patter of a rotary transformer is provided inside the resolver pattern, and the pattern of the rotary transformer and that of the resolver are made integral with each other (For example, JP, 8-136211, A).
However, the following problems and shortcomings exist in the prior art. (1) Because a resolver using a rotary transformer according to JP, 8-136211 is such that the pattern of a rotary transformer is made integral with that of a resolver, the number of working processes can be reduced, and production cost thereof can be decreased. But, the outer diameter must be reduced when making the resolver smaller, the pattern of the rotary transformer is made very small, wherein a lowering in the transformation ratio occurs due to a decrease in a magnetic flux and number of windings, and an appointed detection voltage could not be obtained. Also, because the detection phase pattern links with a magnetic flux produced by the rotary transformer, large residual voltage is generated to cause an angular error to be increased. (2) In the resolver described in JP, 8-84449 and rotary transformer described in JP, 8-306562 the primary side center is misaligned with the secondary side center due to misalignment when attaching a sheet coil of a conductor, and as the sheet coil rotates, a fluctuation component in the mechanical angle of 360° appeared in the amplitude of flux linkage. As described above, in the prior art, there is a problem in that only slight misalignment in attaching a sheet coil causes a large angular error. Also, although the angular error can be decreased if the precision of attaching a sheet coil and of incorporation thereof is improved, the cost is increased instead, wherein an original effect of becoming less expensive may be lost. It is therefore an object of the invention to provide an inexpensive resolver using a sheet coil, having only a small angular error, which can be downsized without resulting in a lowering of the detection voltage and can limit the variation in amplitude of flux linkage even if misalignment occurs when attaching a sheet coil.
SUMMARY OF THE INVENTION
The present invention is a means to solve the above-described problems and shortcomings, and a resolver using a sheet coil according to a first embodiment of the present invention is disclosed below.
That is, a resolver according to the present invention is provided with a disk-shaped rotor and two disk-shaped stators between which the rotor is placed with air gaps in the axial direction thereof, wherein the above-described rotor is such that a rotor side sheet coil is attached to both sides of a disk-shaped soft magnetic material on which are formed a secondary side pattern of a rotary transformer and a resolver excitation phase pattern, and a stator side sheet coil having a rotary transformer primary side pattern formed on a disk-shaped soft magnetic material is attached to one of the stators opposed to the above-described rotary transformer secondary pattern, and a stator side sheet coil having a resolver detection phase pattern formed on a disk-shaped soft magnetic material is attached to the other of the above-described stators opposed to the above-described resolver excitation phase pattern.
Also, the above-described rotor side sheet coil according to the present invention is formed of a single sheet composed of a disk having the above-described resolver excitation phase pattern formed, a disk having the above-described rotary transformer secondary side pattern formed, and a linear portion having a cross-over line that connects the above-described resolver excitation phase pattern and the above-described rotary transformer secondary side pattern to each other.
In addition, the above-described stator side sheet coil is formed of a single sheet composed of a disk having the above-described resolver detection phase pattern formed, a disk having the above-described rotary transformer primary side pattern formed, and a linear portion that links the corresponding two disks with each other.
Further, the above-described rotary transformer secondary side pattern formed on both sides of the disk according to the invention is a pattern eddying from outside to inside, and both the patterns are connected to each other in series, and the above-described resolver excitation phase pattern that is formed at both sides of the disk is a pattern eddying by 2N times in the circumferential direction where N is a natural number, and the center of the eddy on the surface side is disposed at the same position of the eddy on the rear side in the circumferential direction, and 4N eddies are connected to each other in series, wherein the axial multiple angle is NX.
Also, the above-described rotary transformer primary side pattern is formed on both sides of the disk, and both patterns eddying from outside to inside are connected to each other in series, and the above-described resolver detection phase pattern is formed on both sides of the disk, and one side of which is a “&agr;” phase and the other of which is a “&bgr;” phase, wherein 2N patterns eddying in the circumferential direction are disposed, and the center positions of the eddies of the “&agr;” phase and “&bgr;” phase slip by 90/N° from each other in the circumferential direction. Also, 2N eddies are connected to each other in series, wherein the axial angle becomes NX.
Therefore, in the present invention, because the area of the rotary transformer can be increased further than that of the prior art rotary transformers even if the outer diameter thereof is reduced, the detection voltage is lowered beyond that in the prior art. Also, because the patterns of the rotary transformer are not on the same level as that of the resolver patterns, no flux produced by the rotary transformer links with the detection p
Katsuma Takashi
Maemura Akihiko
Shikayama Toru
Armstrong Westerman & Hattori, LLP
Kabushiki Kaisha Yaskawa Kenki
Le Dang
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