Metal working – Plural diverse manufacturing apparatus including means for... – Type of machine
Patent
1991-01-02
1992-03-10
Howell, Daniel W.
Metal working
Plural diverse manufacturing apparatus including means for...
Type of machine
10129R, 318 35, 318 68, 36447402, 36447412, 408 9, 408 10, B23B 4700
Patent
active
050939726
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a control unit mounted on a machine having a workpiece rotating spindle and a tapping tool rotating spindle, and more particularly, to a tapping control unit for controlling the drive of both these spindles so that an end face of a rotating workpiece can be tapped.
BACKGROUND ART
Generally, in tapping an end face of a workpiece, the workpiece is stopped from rotating. Therefore, the tapping operation cannot be performed simultaneously with processing which cannot dispense with the workpiece rotation, e.g., cutting the peripheral surface of the workpiece. As a result, the total required processing time is lengthened, so that the processing efficiency lowers.
DISCLOSURE OF THE INVENTION
The object of the present invention is to provide a tapping control unit capable of controlling the drive of a machine, which has a workpiece rotating spindle and a tapping tool rotating spindle, so that an end face of a rotating workpiece can be tapped.
In order to achieve the above object, according to the present invention, there is provided a tapping control unit for use in a machine where a first spindle fitted with a workpiece is rotated by a first motor, and a second spindle fitted with a tapping tool is rotated by a second motor and axially driven by a third motor. The tapping control unit comprises a first control circuit for controlling the rotation of the first motor, a second control circuit for controlling the rotation of the second motor, a third control circuit for controlling the rotation of the third motor, a first position sensor coupled to the first spindle, and a second position sensor coupled to the second spindle, the second control circuit being adapted to execute position loop control for the first spindle in accordance with position feedback signals respectively supplied from the first and second position sensors and a tapping speed command supplied from a host control unit, thereby rotating the first and second spindles with a speed difference corresponding to the tapping speed command, and the third control circuit being adapted to control the rotation of the third motor so that the second spindle axially moves at a speed corresponding to the rotational speed difference between the first and second spindles.
According to the present invention, as described above, the workpiece and the tapping tool are rotated with the speed difference corresponding to the tapping speed command by executing the position loop control based on the position feedback signals from the first and second position sensors and the tapping speed command from the host control unit, while the first spindle fitted with the workpiece is rotating, and the second spindle is axially moved at the speed corresponding to the rotational speed difference. Thus, the end face of the workpiece can be tapped while rotating the workpiece at any desired rotational speed. As a result, the tapping operation can be performed simultaneously with cutting operation on the peripheral surface of the workpiece, for example, so that the total required processing time can be considerably shortened.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view showing a compound lathe mounted with a tapping control unit according to one embodiment of the present invention;
FIG. 2 is a flowchart showing a tapping control process executed by a processor of a host numerical control unit shown in FIG. 1; and
FIG. 3 is a flowchart showing position control loop processing and speed control loop processing for a second spindle executed by a processor of a second control circuit shown in FIG. 1.
BEST MODE OF CARRYING OUT THE INVENTION
Referring to FIG. 1, a compound lathe, which serves as a tapping apparatus, comprises a first spindle (main spindle) 10 arranged to be rotatable, a second spindle (sub-spindle) 20 aligned with the first spindle and arranged to be rotatable and axially movable, and a tool rest 50 arranged for reciprocal motion in the axial direction of both these spindles and in a direction p
REFERENCES:
patent: 4587697 (1986-05-01), Link et al.
patent: 4722123 (1988-02-01), Pruvot et al.
patent: 4808047 (1989-02-01), Calevich et al.
patent: 4949443 (1990-08-01), Saruwatari
patent: 5010286 (1991-04-01), Nakamura et al.
Fukukura Masaaki
Kaku Masahiro
Kono Shinichi
Fanuc Ltd
Howell Daniel W.
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