Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2000-07-19
2001-08-21
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S071000, C310S179000, C310S208000, C310S254100
Reexamination Certificate
active
06278205
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to an electric motor comprising a first part and a second part which are rotatable with respect to each other about an axis of rotation, wherein the first part comprises a foil-shaped insulating substrate, on which a plurality of series-connected spiral-shaped patterns of conductor tracks are provided and which is bent as a circular-cylindrical body extending, seen in a direction parallel to the axis of rotation, between a first and a second imaginary end surface and being mounted on a carrier near the first end surface, and wherein the second part comprises a permanent magnet unit for generating a magnetic field at the location of the conductor tracks, said first part being provided with connector means for connecting said conductor tracks to an electrical energy source.
The invention further relates to a data storage unit comprising a support for at least one information carrier, an electric motor for rotating the support about an axis of rotation, and a scanning unit for scanning the information carrier.
DESCRIPTION OF PRIOR ART
A data storage unit and an electric motor of the kinds mentioned in the opening paragraphs are known from EP-B-0 764 357. The known data storage unit is a hard disc drive, wherein a plurality of hard discs are arranged in mutually parallel positions on the rotatable support. The known electric motor, which is used to rotate the support about the axis of rotation, comprises a circular-cylindrical stator body comprising three layers of the foil-shaped insulating substrate. The patterns of conductor tracks form a three-phase electric coil system, wherein each layer of the stator body comprises one of the respective phases. The conductor tracks constitute relatively thin copper tracks, which are provided on the substrate by means of an etching process. The known electric motor further comprises a circular-cylindrical rotor body, which is fastened to the support and comprises a circular-cylindrical permanent magnet and a circular-cylindrical closing yoke, the stator body being arranged in a circular-cylindrical gap which is present between the magnet and the closing yoke. The connector means of the known electric motor comprise two strip-like foil elements for each phase of the coil system, on which foil elements extensions of an initial and an end conductor track of the relevant phase are provided. Said strip-like foil elements extend in an imaginary plane extending through the substrate, and are arranged outside the boundaries of the substrate formed by the first and the second end surface.
A disadvantage of the known data storage unit and the known electric motor used therein is that, during the manufacturing process of the first part of the motor and the manufacturing process of the motor, the strip-like foil elements of the connector means of the motor can easily be bent under the influence of inaccurate handling forces and movements, whereby the complete substrate can be rendered useless for the further manufacturing process. Thus, to avoid an excessive percentage of rejected parts during the manufacturing process, the accuracy of the manufacturing process must be relatively high.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an electric motor and a data storage unit of the kinds mentioned in the opening paragraphs, in which the disadvantage of the known electric motor and the known data storage unit is prevented as much as possible.
To achieve this object, an electric motor in accordance with the invention is characterized in that said connector means comprise a first connector element, which is provided on the substrate between the first and the second end surface near the first end surface and is electrically connected to the conductor tracks, and a second connector element, which is provided on the carrier and is electrically connected to the first connector element.
To achieve this object, a data storage unit in accordance with the invention is characterized in that the electric motor used therein is an electric motor in accordance with the invention.
Since the first connector element is provided on the substrate between the first and the second end surface of the substrate, the first connector element is protected against damage, which could result from inaccurate handling forces and movements during the manufacturing process. The first connector element can be connected to the energy source via the second connector element, which is also effectively protected against damage as a result of its presence on the carrier. In this way, a practical and robust construction of the connector means is achieved.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A particular embodiment of an electric motor in accordance with the invention is characterized in that the first connector element comprises an additional conductor track. The additional conductor track can be provided on the substrate in a similar manner as and simultaneously with the patterns of conductor tracks, for example by means of an etch process. Thus, the manufacturing process of the electric motor is further simplified. Besides, said additional conductor track is substantially not susceptible to damage caused by inaccurate handling forces and movements during the manufacturing process of the motor.
A further embodiment of an electric motor in accordance with the invention is characterized in that the additional conductor track extends substantially parallel to the first end surface. In this further embodiment, a great freedom of design is achieved regarding the position of the second connector element on the carrier, because the length of the additional conductor track can be adapted to the desired position of the second connector element.
Yet another embodiment of an electric motor in accordance with the invention is characterized in that the substrate is provided with a metal track extending near the first end surface, substantially parallel to the first end surface, and substantially over the complete length of the substrate, wherein part of said metal track constitutes the additional conductor track. As a result of the presence of said metal track, a substantially uniform bending stiffness of the substrate is achieved over the complete length of the substrate, so that said circular-cylindrical body of the first part of the motor, which is formed by bending said substrate, has an accurate circular-cylindrical form.
A particular embodiment of an electric motor in accordance with the invention is characterized in that the circular-cylindrical body comprises at least two substrate layers, wherein each layer, which is present between another layer and a connector element on the carrier connected to the other layer, is provided with an opening in the substrate through which said connector element extends. By virtue of said opening in each relevant layer, each layer can be provided with a connector element which is positioned on the substrate between the first and the second end surface of the substrate. Since the connector element on each relevant layer is provided near the first end surface, the opening can be formed as a simple recess in the edge of the substrate which is present near the first end surface.
REFERENCES:
patent: 4645961 (1987-02-01), Malsky
patent: 4843269 (1989-06-01), Shramo
patent: 4962329 (1990-10-01), Fujita et al.
patent: 5331244 (1994-07-01), Rabe
patent: 5510663 (1996-04-01), Van Loenen
patent: 0764357B1 (1997-03-01), None
Lam Thanh
Ramirez Nestor
U.S. Philips Corpration
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