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US 4,646,596 AGranted
Machine tools
OwnerWalter C. Edwards, Robert J. H. Winterbottominventors
Life of this patent
Estimating the term…
Abstract
A machine tool for machining rotating workpieces at high rotational speeds and, in particular, with multiple tool movements within a revolution of the workpiece, comprises a low-inertia high-torque motor having an output shaft and a tool holder mounted for movement relatively to the motor. A cam or other single element connection drivable connects the output shaft and the tool holder and the motor can be operated by control apparatus to so oscillate the output shaft that the tool is moved rapidly back and forth in phase with the output shaft oscillation and in correspondence with the rotation of the workpiece to perform required machining movements.
Claims45
A machine tool for turning or facing a surface of a workpiece rotating about an axis to a changing profile in two mutually perpendicular directions extending axially and radially of the rotating workpiece comprising:
- a rotatable workpiece support for holding and rotating the workpiece;
- a workpiece angular position transducer for producing a signal representing the angular position of the workpiece,
- a tool support carriage supported for movement along a translational axis which extends in one of said directions,
- a carriage position transducer for producing a signal representing the position of the carriage along the translational axis,
- a tool holder carried on said tool support carriage and supported for movement in the other of said directions,
- a tool holder position transducer for producing a feedback signal representing the position of the tool holder in the other of said directions,
- a control apparatus for receiving the workpiece angular position signal and the tool carriage position signal from said transducers and for generating a single varying control signal corresponding to required tool positions for workpiece angular and tool carriage positions represented by the transducer signals for the production of a predetermined changing non-uniform profile on a surface of the workpiece in the axial and radial directions,
- a single low-inertia high-torque motor for receiving a control current,
- a rotor of the motor which is rotated responsive to the control current by a maximum of less than a revolution and whose successive angular positions within said revolution correspond to instantaneous values of the control current,
- a rotor velocity signal generator for producing a feedback signal representing the angular velocity of the rotor,
- a closed loop control system for receiving the single varying control signal, the tool position feedback signal, and the rotor velocity feedback signal, and for producing therefrom the control current for said motor,
- a single element transfer member connected directly to the rotor and acting directly on the tool holder for translating angular movements of the motor output shaft with substantially no lag in the transmission of the shaft movements into corresponding movements of a tool held by the tool holder,
- the rotor, the transfer member, and the control system with feedback having together an overall system bandwidth of at least 150 Hz to move the tool to each required position during machining to machine the surface of the workpiece to the required non-uniform profile in said two directions.
10 more elements
A machine tool for boring the interior of a hollow workpiece rotating about an axis to a non-cylindrical profile in axial and radial directions during relative rotation therebetween and comprising:
- a rotatable workpiece support for holding and rotating the workpiece,
- a workpiece angular position transducer for producing a signal representing the angular position of the workpiece,
- a tool support carriage supported for movement along a translational axis which extends in said axial direction,
- a carriage position transducer for producing a signal representing the position of the carriage along the translational axis,
- an elongate boring bar mounted intermediate the ends thereof for pivotal movement in said radial direction about an axis normal to the axis of rotation of the workpiece and carried on said tool support carriage,
- a tool carried at one end of the boring bar,
- a boring bar position transducer for producing a feedback signal representing the pivotal position of the boring bar,
- a control apparatus for receiving the workpiece angular position signal and the tool carriage position signal from said transducers and for generating a single varying control signal corresponding to required tool positions for workpiece angular and tool carriage positions represented by the transducer signals for the production of a predetermined non-cylindrical profile of the interior of the hollow workpiece in the axial and radial directions,
- a single low-inertia high-torque motor mounted adjacent an end of said boring bar opposite said one end for receiving a control current,
- a rotor of the motor which is rotated responsive to the control current by a maximum of less than a revolution and whose successive angular positions within said revolution correspond to instantaneous values of the control current,
- a rotor velocity signal generator for producing a feedback signal representing the angular velocity of the rotor,
- a closed loop control system for receiving the single varying control signal, the tool position feedback signal, and the rotor velocity feedback signal, and for producing therefrom the control current for sadi motor,
- a single element drive transfer member connected directly to the rotor of the motor and acting directly on said end of the boring bar opposite said one end for translating angular movements of the motor output shaft with substantially no lag in the transmission of the shaft movements into corresponding movements of the tool,
- the rotor, the transfer member, and the control system with feedback having together an overall system bandwidth of at least 150 Hz to move the tool to each required position during machining to bore the interior of the hollow workpiece to the required non-cylindrical profile in axial and radial directions.
11 more elements
A machine tool for machining a surface of a workpiece rotating about an axis to a changing profile in two mutually perpendicular directions extending axially and radially of the rotating workpiece comprising:
- a rotatable workpiece support for holding and rotating the workpiece,
- a workpiece angular position transducer means for producing a signal representing the angular position of the workpiece,
- a tool support carriage supported for movement along a translational axis which extends in one of said directions,
- a carriage position transducer means for producing a signal representing the position of the carriage along the translational axis,
- a tool holder on said tool support carriage and supported for movement in the other of said directions,
- a tool holder transducer means for producing a feedback signal representing the position of the tool holder in the other of said directions,
- control means for receiving the workpiece angular position signal and the tool carriage position signal from said transducer means and for generating a signal varying control signal corresponding to required tool positions for workpiece angular and tool carriage positions represented by the transducer means signals for the production of a predetermined changing non-uniform profile on a surface of the workpiece in the axial and radial directions,
- a single low-inertia high-torque motor for receiving a control current,
- a rotor of the motor which is rotated responsive to the control current by a maximum of less than a revolution and whose successive angular positions within said revolution correspond to instantaneous values of the control current,
- a rotor velocity signal generator means for producing a feedback signal representing the angular velocity of the rotor,
- a closed loop control system including means for receiving the single varying control signal, the tool position feedback signal, and the rotor velocity feedback signal, and for producing therefrom the control current for said motor, and
- a single element drive transfer member connected directly to the rotor and acting directly on the tool holder for translating angular movements of the motor output shaft with substantially no lag in the transmission of shaft movements into corresponding movements of a tool held by the tool holder,
- the rotor, the drive transfer member, and the control system with feedback providing a tool positioning means having together an overall system bandwidth of at least 150 Hz for moving the tool to each required position during machining to machine the surface of the workpiece to the required non-uniform profile in said two directions.
10 more elements
Dependencies are inferred from the claim text.