Electricity: motive power systems – Positional servo systems
Reexamination Certificate
2000-04-19
2001-10-30
Ip, Paul (Department: 2837)
Electricity: motive power systems
Positional servo systems
C318S038000, C318S040000, C310S080000, C074S089100, C074S640000
Reexamination Certificate
active
06310455
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a positioning and actuating drive.
2. Description of Related Art
Positioning and actuating drives are used in different industries for adjusting and positioning movable parts with respect to one another. Applications of such positioning and actuating drives include, for example, input feed axes and format adjustment devices in printing presses and textile machinery, woodworking machinery, packaging machines, bakery equipment, wrapping and labeling machines, as well as handling devices and attachments upstream and downstream from these machines.
Such positioning and actuating drives typically have an electric motor, which often drives an output shaft via a gear box, the output shaft being responsible for the positioning and actuating effect. A position phase angle sensor is coupled to the output shaft and generates position feedback and, optionally, velocity and/or acceleration feedback. If a direct current (i.e., DC) motor is used, typically a motor phase angle sensor is used to determine the rotor position of the motor for commutating and energizing the motor windings. The electric motor, the gearbox, and the phase angle sensor make the positioning and actuating drive occupy a large amount of space.
Thus there exists a problem in the art with the size of positioning and actuating drives. It would be desirable to provide a compact positioning and actuating drive in order to decrease the required volume, and thus increase the opportunity for incorporating or installing the positioning and actuating drive.
SUMMARY OF THE INVENTION
According to an embodiment of the present invention, a positioning and actuating drive has the features of a DC motor, which has a stator and a rotor rotatably mounted coaxially in the stator. A rotor shaft of the rotor is designed as a hollow shaft, and has an output shaft rotatably mounted coaxially in the rotor shaft. A gear box which drivingly connects the rotor shaft to the output shaft is arranged at the first end face of the electric motor, and the output shaft protruding outward from the rotor shaft and the gear box at this first end face. A position phase angle sensor and a motor phase angle sensor are arranged at the opposite second end face of the electric motor. The position phase angle sensor has a position phase angle sensing unit mounted on the output shaft and a fixed position phase angle sensor. The motor phase angle sensor has a motor phase angle sensing unit mounted on the rotor shaft and a fixed motor phase angle sensor. Electronics for detecting and processing the signals from the position phase angle sensor and of the phase angle sensor may be included in a housing, which encloses the electric motor, the gear box, the position phase angle sensor, the motor phase angle sensor, and the electronics. The output shaft may protrude at its end face.
Another embodiment of the invention provides a positioning and actuating drive where the position phase angle sensor includes a positioning magnet mounted on the end of the output shaft and a magnetoresisitive sensor disposed on a circuit board.
Another embodiment of the invention provides a positioning and actuating drive where the motor phase angle sensor has a ring magnet mounted on the end face end of the rotor shaft and at least one Hall sensor mounted on a circuit board.
In yet another embodiment of the invention, the gear box is a tooth-coupled gear, which engages the peripheral teeth of an end section of the rotor shaft protruding from the rotor and the peripheral teeth of a section of the output shaft protruding from the rotor shaft.
In still another embodiment of the invention, the housing includes a housing block, a housing tube and covers that seal the housing at both ends. The housing tube accommodates the electric motor, the position phase angle sensor, the motor phase angle sensor and the respective electronics, while the housing block accommodates the gear box.
In a further embodiment of the invention, the housing block has a pot-shaped design with its bottom adjacent to the housing tube and sealed at its open end by a cover.
In yet a further embodiment of the invention, the housing tube axially protrudes from the electric motor at the end away from the gear box and forms a space, sealed by a second cover, for one or more circuit boards, which carry the position phase angle sensor and of the motor phase angle sensor, as well as the electronics for detecting and processing the data of these sensors and for controlling and supplying the electric motor.
In a further embodiment of the invention, the ring magnet coaxially encloses the position magnet.
Generally, according to the present invention, the electric motor, the gearbox, the position phase angle sensor and the motor phase angle sensor are integrated in a common housing. The housing may also include the electronics for detecting and processing the signals from the phase angle sensor. In particular, the rotor shaft of the electric motor is designed as a hollow shaft, in which the drive shaft is mounted coaxially. The gearbox is arranged at one end face of the electric motor, the output shaft passing coaxially through the gearbox, and the end of the shaft which protrudes from the gear box being provided with a coupling. The drive shaft passes coaxially through the rotor of the electric motor and carries a position phase angle sensor at the second end face of the electric motor opposite the gear box. The motor phase angle sensor arranged on the rotor shaft coaxially encloses the position phase angle sensor. The scanning sensors of both phase angle sensors are arranged on a common circuit board, which also carries the electronics for detecting and processing the signals of these sensors. Thus the phase angle sensors and the respective electronics can be mounted in the housing in a compact manner. Preferably a second circuit board, carrying the control and power electronics for the motor power supply, can be integrated in the housing parallel to the circuit board carrying the sensors. Since both circuit boards are arranged parallel to the end face of the electric motor, i.e., perpendicular to the axis of the rotor shaft and the output shaft, these circuit boards add little to the overall dimensions of the housing.
The phase angle sensors may beneficially be magnetic phase angle sensors, which require little space for the units coupled to the respective shaft and for the respective sensors.
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Held Siegfried
Siraky Josef
Hutchins, Wheeler & Dittmar
Ip Paul
Max Stegmann GmbH Antriebstechnik-Elektronik
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