Electricity: motive power systems – Motor-reversing
Reexamination Certificate
2001-09-19
2003-12-02
Nappi, Robert E. (Department: 2837)
Electricity: motive power systems
Motor-reversing
C318S256000, C318S282000, C318S283000, C318S284000, C318S285000, C318S286000, C318S466000, C318S467000, C318S468000, C318S469000, C318S293000, C318S626000, C318S696000, C318S010000
Reexamination Certificate
active
06657406
ABSTRACT:
TECHNICAL FIELD
This invention relates to the control of a motor-driven actuator, and more particularly to a motor control for reducing audible noise due to armature shaft end-play.
BACKGROUND OF THE INVENTION
Control systems designed to position a load device frequently utilize an actuator coupled to a DC motor through a gear arrangement that provides a mechanical advantage. This is a common configuration because small permanent magnet DC motors may be produced at low cost, and actuator movement can be detected without position sensors by counting commutation pulses of the motor; see, for example, the U.S. Pat. No. 6,078,154 to Manlove et al., issued Jun. 20, 2000, and incorporated herein by reference. In many such systems, a worm gear is used to couple the armature of the motor to an output gear having an axis perpendicular to the armature; this is a popular arrangement because the worm gear can be formed or attached directly to the armature shaft, and because it provides a reasonably high mechanical advantage and virtually eliminates back-driving of the armature by the actuator. However, a drawback of this arrangement occurs due to axial shifting of the armature shaft each time the motor rotation is reversed. Mechanical stops are provided for limiting axial movement of the armature shaft, and clunking noises occur when the shaft forcibly impacts the stops. While the axial shifting and clunking noise can be virtually eliminated by minimizing the armature end-play, a certain amount of end-play is highly desirable from the standpoints of manufacturing cost and operating efficiency. Accordingly, what is needed is a way of minimizing the audible noise associated with axial shifting of the motor armature shaft while retaining the above-mentioned benefits of low cost and high efficiency.
SUMMARY OF THE INVENTION
The present invention is directed to an improved method of operation for a motor-driven actuator in which the motor is coupled to a load device through a worm gear on an armature shaft of the motor, wherein the motor is energized in a series of pulses during an initial period of motor operation when reversal of the motor is commanded. The pulsed energization produces a slow initial axial movement of the motor armature without moving the load device, minimizing the contact force between the armature shaft and a respective mechanical end stop of the motor. Rotation of the motor is determined by identifying and counting motor current pulses due to commutation, and the pulse count is adjusted at each reversal of the motor to compensate for motor current pulses caused by the pulsed energization.
REFERENCES:
patent: 4134052 (1979-01-01), Wanlass
patent: 4364111 (1982-12-01), Jocz
patent: 4455511 (1984-06-01), Stewart
patent: 4467250 (1984-08-01), Thomasson
patent: 4591868 (1986-05-01), Cusey et al.
patent: 4912380 (1990-03-01), Zylstra et al.
patent: 5410226 (1995-04-01), Sekiguchi et al.
patent: 5634676 (1997-06-01), Feder
patent: 5650698 (1997-07-01), Ito et al.
patent: 5693993 (1997-12-01), Ito et al.
patent: 5772274 (1998-06-01), Tokarz
patent: 5804938 (1998-09-01), Richmond et al.
patent: 5844382 (1998-12-01), Dan
patent: 5905345 (1999-05-01), Zimmer et al.
patent: 6075298 (2000-06-01), Maue et al.
patent: 6078154 (2000-06-01), Manlove et al.
patent: 6107759 (2000-08-01), Miller
patent: 6111378 (2000-08-01), LeMay et al.
patent: 6112583 (2000-09-01), Yamamura
patent: 6297606 (2001-10-01), Yoshioka et al.
patent: 6320342 (2001-11-01), Yoshioka et al.
patent: 6424109 (2002-07-01), Ochiai et al.
patent: 2000-324756 (2000-11-01), None
Enzinna Donald John
Parisi Mark Joseph
Delphi Technologies Inc.
Griffin Patrick M.
Nappi Robert E.
Smith Tyrone
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