Electricity: motive power systems – Positional servo systems – Program- or pattern-controlled systems
Patent
1987-07-30
1989-03-28
Shoop, Jr., William M.
Electricity: motive power systems
Positional servo systems
Program- or pattern-controlled systems
51 34C, 5116593, G05B 1918
Patent
active
048167312
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a honing machine. Honing machines are used for fine-finishing cylindrical bores in work-pieces such as automobile cylinder blocks and hydraulic and pneumatic components of all kinds.
In general, a honing machine has a rotatable spindle which carries at its end abrasive stones mounted in carriers which may be expanded radially. In a honing operation the spindle enters the bore in the work-piece and is rotated as the work-piece and spindle are reciprocated with respect to each other. Radial pressure is applied to urge the stones against the wall of the bore. Forward movement of the spindle causes the stones to trace a helical path in the bore in one sense and reverse movement of the spindle causes the stones to trace a helical path in the opposite sense. Consequently, a cross-hatched honing pattern is made in the bore. For optimum finishing it is found to be important to control the cross-hatch pattern accurately.
The cross-hatch angle is a function of the stroke velocity in relation to the spindle speed. Spindle speed can effectively be maintained constant by controlling a continuously rotating spindle motor of significant inertia. The problem of cross-hatch pattern control resolves itself, therefore, to control of stroke velocity. However, because of the reciprocating movement, the spindle must be repetitively accelerated and decelerated having regard to its position with respect to the work-piece.
In order to control stroke reversal in honing machines it has been the practice to use limit switches or mechanical trips for valves etc., near each end of the stroke. These may be micro-switches, proximity sensors, or the like which, when activated, reverse the drive to the stroke mechanism. The use of limit switches gives an inherently asymmetrical stroke velocity characteristic, and while offering repeatability, does not allow precision control. Often, the reciprocating mechanism is hydraulic. While this is a convenient way of driving a system for a large-scale machine with a high power requirement, it again does not lend itself to precision control. The characteristics of the hydraulic system change with temperature, for example. The present invention seeks to provide a honing machine offering very precise control, and while the principles are applicable to large-scale machines, the principal application for the invention is found in small-piece work where precision is particularly important.
According to one aspect of the invention there is provided a honing machine comprising a spindle; an expandable honing stone carrier at the end of the spindle; a drive motor for rotating the spindle; a direct-current stroke motor for reciprocating the spindle with respect to a work-piece; a position transducer arrangement for giving a digital output in accordance with the linear stroke position of the spindle with respect to the work-piece; a micro-processor; a memory unit for the micro-processor, which memory unit holds a predetermined acceleration profile look-up table; and an input console for manually applying input parameters, the micro-processor being programmed (a) to accept inputs from the console from which can be derived at least the required start and end positions of the stroke and the required mid-stroke speed of the spindle, (b) to sample the input from the position transducer arrangement periodically, (c) to compare the actual position of the spindle with the look-up table to drive a position error signal whereby the stroke motor is driven to correct the error and cause the spindle to follow the acceleration profile alternately in acceleration and deceleration modes, (d) to cause the spindle to continue at the mid-stroke speed between acceleration and deceleration when the mid-stroke speed is reached, and (e) to cause switching at the mid-stroke position from acceleration to deceleration mode if the required mid-stroke speed has not been reached.
This arrangement ensures symmetrical acceleration and deceleration of the spindle even if the required mid-stroke speed is not reached.
REFERENCES:
patent: 3126672 (1964-03-01), Calvert et al.
patent: 3404490 (1968-10-01), Entabrook
patent: 3664217 (1972-05-01), Schiewek et al.
patent: 4143310 (1979-03-01), Fujinawa et al.
patent: 4418305 (1983-11-01), Otsuki et al.
patent: 4455789 (1984-06-01), Gehring
patent: 4679357 (1987-07-01), Richter et al.
Bassirat Hamid R.
Boulton Michael A.
Roberts Joseph I.
Bergmann Saul M.
Delapena Honing Equipment Limited
Shoop Jr. William M.
LandOfFree
Honing machine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Honing machine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Honing machine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1661645