Electricity: motive power systems – Switched reluctance motor commutation control
Reexamination Certificate
1999-01-21
2003-01-21
Fletcher, Marlon T. (Department: 2837)
Electricity: motive power systems
Switched reluctance motor commutation control
C318S434000, C388S800000
Reexamination Certificate
active
06509704
ABSTRACT:
FIELD OF THE INVENTION
The invention relates generally to motors and, more particularly, the invention relates to motors utilized within low profile blowers or fans that are installed for cooling purposes within the chassis of electronic equipment or other equipment.
BACKGROUND OF THE INVENTION
Flat-type blowers or fans (“flat blowers”) commonly are utilized to cool electronic equipment. One exemplary flat blower is the DIPLOMAT™ blower, available from Comair Rotron, Inc. of San Ysidro, Calif. Flat blowers commonly have a relatively low profile (i.e., cross-sectional dimension) to minimize the volume that is required to mount such type of blower within electronic equipment. The above noted DIPLOMAT™ blower, for example, has a profile of about 2.5 inches.
Although relatively thin, there is a continuing need to further reduce the profile of flat blowers. For example, reducing the thickness by as little as 0.25 inches is considered a significant profile reduction. The minimum thickness of a flat blower is limited, however, by the size of the motor that rotates the blower impeller. For example, the above noted DIPLOMAT™ blower includes a motor with a rotor coupled to an impeller. In addition to poles, bearings, motor windings, and other known motor elements, the motor also includes the motor electronics (e.g., the motor control and power regulation circuitry) within a motor housing that itself is contained within a blower housing. The motor electronics within the motor housing necessarily increases the size of the stator stack (i.e., poles, coils, and circuitry), consequently increasing the minimum thickness of the blower.
In addition to having a relatively low profile, it also is desirable for a flat blower to be mountable in different configurations within the chassis of electronic equipment. The different configurations enable the blower exhaust port to direct outward air flow in a desired direction, such as away from the interior of the electronic equipment being cooled. Accordingly, the electronics in a flat blower commonly are connectible to the electronic equipment (e.g., to derive power or receive controlling data signals from the electronics) by means of one or more wires extending from the blower. Use of wires is inconvenient, however, since the wires must be manually connected to the electronics of the equipment within the equipment chassis.
SUMMARY OF THE INVENTION
In accordance with one aspect of the invention, a flat blower utilizes surface mounting techniques for mounting the blower electronics on a thin laminated circuit board to reduce the blower profile. In some embodiments, the blower has a profile of no greater than about 1.65 inches. To that end, the blower includes a stator, and a rotor rotatably coupled to the stator. The stator includes a coil, a pole coupled with the coil, and a laminated circuit board having blower control circuitry and pads for electrically connecting the blower control circuitry to the coil. Use of laminated surface mounting techniques to mount the control circuitry on the laminated circuit board thus eliminates the discrete electronic components and the wires connecting such components. In preferred embodiments, the laminated circuit board has a thickness of no greater than about 0.032 inches.
In preferred embodiments, the rotor has a bottom face with a bottom face area, and the laminated circuit board has an opposing region that is coaxial with and faces the bottom face.
The bottom face area is the same size as the area of the opposing area. The control circuitry is located outside the opposing region.
In accordance with other aspects of the invention, the blower control circuitry may include a switching circuit for switching the polarity of the coil to control rotor rotation, and regulator circuitry for regulating at least one of blower input current and voltage. The blower control circuitry also may include a Hall effect sensor, and blower performance feedback circuitry to monitor blower performance. The laminated circuit board may include circuit traces to connect each of the different elements that comprise the blower control circuitry. The different circuit elements may be laminated surface mounted circuit elements.
The blower preferably is couplable with an electronic device. The laminated circuit board thus may include a first port coupled to the blower performance feedback circuitry for receiving and transmitting signals between the blower performance feedback circuitry and the electronic device. In other embodiments, the blower includes a housing with four sides and a front face, where the front face and one of the sides each define respective air inlet and exhaust openings. The rotor preferably is configured to direct air flow into the housing through the front face air inlet and to direct air out of the housing through the exhaust opening.
In accordance with other aspects of the invention, the electronic device includes a coupler and the blower includes a connector, which is connected to the port. The connector mechanically connects with the coupler to electrically connect the port to the electronic device. The blower also may be mechanically couplable to the electronic device in first and second configurations. The connector may be mountable on the blower at a first location when the blower is mounted in the first configuration. In a similar manner, the connector may be mountable on the blower at a second location when the blower is mounted in the second configuration. Moreover, the housing may have a light emitting diode on one or more of the surfaces of the housing.
In accordance with still another aspect of the invention, circuit elements in a motor are distributed to reduce the motor profile. To that end, the motor includes a stator, a rotor coupled to the stator and having a bottom face with a bottom face area, and a laminated circuit board having circuitry that controls the rotation of the rotor. The laminated circuit board has an opposing region with an opposing region area that is identical to the bottom face area. The bottom face is coaxial with the opposing region. The circuitry preferably is positioned on the circuit board so that it is not within the opposing region on the laminated circuit board.
In preferred embodiments, the bottom face of the rotor is spaced from the opposite region of the laminated circuit board. The circuit board may include other circuitry that is not within the opposing region. In addition, the circuit board preferably includes either or both of laminated surface mounted circuit elements and discrete circuit elements. The circuit elements may include a number of elements, including resistors or transistors. In other embodiments, the circuit elements includes a switching circuit for controlling the rotation of the rotor. The circuit elements preferably are connected by circuit traces laminated onto the laminated circuit board.
In other embodiments, the rotor includes an impeller. The motor also may include a housing for containing the rotor, stator, and laminated circuit board. The laminated circuit board preferably is mounted upon a rear face of the housing. In some embodiments, the bottom face and opposing region are circularly shaped. In preferred embodiments, however, the bottom face and opposing region are both toroidally shaped (i.e., ring-shaped, similar to a doughnut).
In accordance with other aspects of the invention, a motor includes a stator, a rotor coupled to the stator and having a bottom face with a bottom face area, a housing with a housing interior, and circuitry that controls the rotation of the rotor. The housing has an interior region that faces the bottom face of the rotor, and has an identical area to the bottom face area. In preferred embodiments, the bottom face also is coaxial with the opposing region. The circuitry preferably is positioned within the housing so that it is not within the opposing region on the laminated circuit board.
In many embodiments, the opposing region may include a volume extending from the bottom face of the rotor, to a bottom interior su
Bromberg & Sunstein LLP
Comair Rotron Inc.
Duda Rina I.
Fletcher Marlon T.
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