Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1998-12-15
2004-03-09
Tamai, Karl (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S268000, C310S06800R, C310S052000, C310S064000, C180S065510, C180S065600
Reexamination Certificate
active
06703742
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to electric motors, specifically to an electric motor where the rotor of the motor also functions as a drive wheel.
2. Description of the Related Art
At least three United States patents apply to electric motors where a portion of the electric motor serves as a drive wheel, rather than providing power to a shaft which transfers such power to another component. These are U.S. Pat. No. 3,548,965 of John J. Pierro; U.S. Pat. No. 5,164,623 of Vasily V. Shkondin; and U.S. Pat. No. 5,721,473 of LeRoy M. DeVries.
U.S. Pat. No. 3,548,965 involves a rather complicated rotor primarily composed of two adjacent ferromagnetic circles, each having projections which extend toward the other circle and which projections from one circle are interdigitated with the projections from another circle. The rotor, itself, contains no magnet—either permanent or electromagnetic. A field excitation coil projects a magnetic field into both circles of the rotor. (It is stated that in some cases the field excitation coil may be replaced with one or more permanent magnets.) The magnetic field created by the field excitation coil interacts with a magnetic field created by stator conductor windings. To produce rotation of the rotor, the electric current through the stator conductor windings is supplied at a frequency which is calculated from a formula which includes the tangential velocity of the rotor. Such tangential velocity is determined by a commutator which is “preferably of electromagnetic type . . . ”
The motor of U.S. Pat. No. 5,164,623 utilizes a mechanic commutator, which—being a mechanical device in which different physical parts make moving contact with one another—is subject to wear as well as physical breakage and, therefore, to malfunction. Additionally, from the drawings it appears that the electromagnets of the rotor are located radially outward from the (preferably permanent) magnets of the stator. The disclosure and claims merely state that the “magnetic members” of the stator are mounted on the circumference of the stator and face the electromagnets of the rotor.
And the rotor associated with the motor of U.S. Pat. No. 5,721,473 includes both permanent magnets and electromagnets. It is suggested on lines 62 through 64 in column 5 of U.S. Pat. No. 5,721,473 that the electromagnets of the rotor are necessary in order to achieve adequate acceleration: “When the electromagnets 16 are magnetized and incited by the wire coil stator 17, a wheel accelerates very fast.” And, although the disclosure does not clearly specify the orientation of the magnets on the rotor with respect to the “wire coil stator,” the drawings and the claim indicate that the magnets of the rotor are located radially outward from the “wire coil stator.” In pertinent part, the claim states: “a tire and rim rotor which includes a plurality of oppositely placed interchangeable permanent and electro magnets that rotate said tire and rim rotor by means of an electric field excited by an interchangeable wire coil stator secured onto a stationary axle . . . ”
In its description of the prior art, U.S. Pat. No. 5,164,623 discusses several patents issued by the former Soviet Union but states that the “independent-drive wheel[s]” of such patents have “poor controllability because of the absence of a link between dynamics of rotation and control signals.”
SUMMARY OF THE INVENTION
The present Electric Motor with Rotor Being a Drive Wheel minimizes the possibility of failure by not utilizing mechanical commutators. Moreover, the current invention does not require the use of a formula to compute a frequency for the time when the electromagnets should be energized.
In the present invention, permanent magnets are placed upon one or both of the lateral sides of the drive wheel, forming the rotor. Electromagnets are attached to the structure that supports the axle for the drive wheel, creating the stator. Such electromagnets are arranged generally in a plane that is substantially parallel to, but not within, the plane or planes containing the permanent magnets and are sufficiently close to the permanent magnets that the magnetic fields of the electromagnets and the permanent magnets will interact with one another. If permanent magnets are placed upon both of the lateral sides of the drive wheel, electromagnets may be placed upon both sides of the structure that supports the axle for the drive wheel.
A sensor mounted on the structure that supports the axle for the drive wheel simply determines when a pole of a permanent magnet approaches or is near such sensor. The sensor is so located (1) that when such pole approaches or is near the sensor, magnetic attraction or repulsion between the permanent magnet and an electromagnet will produce a force in the direction that it is desired to rotate the drive wheel and (2) that when the opposite pole of the electromagnet approaches or is near the sensor, magnetic attraction or repulsion between the permanent magnet and an electromagnet would not produce a force in the direction that it is desired to rotate the drive wheel.
Three methods are employed for utilizing the information from the sensor both (1) to assure that the electromagnets will be energized only when such energization will produce a force in the desired direction and (2) to control the speed of the drive wheel.
The control of speed depends upon the fact that the speed of the drive wheel is proportional to the average power (and, therefore, the average voltage) supplied to the electromagnets. Consequently, the speed of the drive wheel is determined by regulating the average voltage that is supplied to the electromagnets.
All three methods control such average voltage by regulating the percentage of time that voltage is supplied to the electromagnets. This is accomplished by closing a switch (preferably an electronic switch—such as a transistor, a triac, or a semiconductor-controlled rectifier), i.e., substantially reducing the resistance between the terminals of the switch, in a circuit between a source of electrical energy, preferably a battery or other generator of direct current, and the electromagnets for such desired percentage of time.
To assure that force is produced only in the desired direction, the first method for closing the switch operates only between the time that the first pole of a permanent magnet approaches the sensor and the time that the second pole of the permanent magnet approaches the sensor; the second and third methods, only when a pole of polarity to which the sensor is sensitive is near such sensor. Outside of such periods, the switch is left open because no signal is sent to close such switch.
In the first method, input of the desired speed can be provided to a computer through any means that is well known in the art. The sensor is in communication with the computer and informs the computer when a pole of a permanent magnet has approached the sensor. The computer then begins producing a signal to close the switch. Preferably, the output signal from the computer will be in the form of a square wave, i.e., a periodic wave which has a constant voltage amplitude when the output is being supplied and zero amplitude during the remainder of the period. The computer communicates with the switch so that the output signal from the computer is sent to the switch and causes such switch to be closed for the proportion of the period during which the output from the computer is non-zero, i.e. when a voltage is being supplied by the computer. The computer adjusts the non-zero proportion of the period to achieve the desired average voltage being transmitted from the source of electrical energy through the switch to the electromagnets and, consequently, the desired average speed of the drive wheel. When the sensor detects that the opposite pole of the permanent magnet has approached the sensor, the sensor so informs the computer; and the computer terminates the production of an output signal, causing the switch to be open.
In a second method, t
Brandley Adam K.
Irwin John R.
Fehr Thompson E.
Fehr Law Firm
Tamai Karl
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