Apparatus for confirming movement of tap when rigid tapping

• US 5,062,744 A
• Filed: 03/26/1990
• Issued: 11/05/1991
• Est. Priority Date: 08/03/1988
• Status: Expired due to Fees

• Current Assignee: Fanuc Ltd (Fanuc Corporation)
• Original Assignee: Fanuc Ltd (Fanuc Corporation)
• Inventors: Nakamura, Kosei, Numai, Kazuhisa
• Primary Examiner(s): Howell, Daniel W.
• Application Number:
  US07/474,758
• Time in Patent Office: 589 Days
• Field of Search: 408/5, 408/6, 408/8, 408/9, 408/10, 408/11, 10/129 R, 10/139 R, 364/474.02, 364/474.12, 364/474.16
• US Class Current: 408/8
• CPC Class Codes: B23G 1/16 in holes of workpieces by taps B23G1/26, B23G1/32, B23G1/36 take precedence
• CPC Class Codes: G05B 19/186 Generation of screw- or gearlike surfaces
• CPC Class Codes: G05B 19/4062 Monitoring servoloop, e.g. overload of servomotor, loss of feedback or reference
• CPC Class Codes: G05B 2219/34457 Emit alarm signal
• CPC Class Codes: G05B 2219/42268 Safety, excess in error
• CPC Class Codes: G05B 2219/45216 Tapping
• CPC Class Codes: G05B 2219/50234 Synchronize two spindles, axis, electronic transmission, line shafting
• CPC Class Codes: Y10T 408/16 with control means energized in response to activator stimulated by condition sensor

Abstract

When tapping is effected by a tap driven by a built-in spindle motor (12) and another motor (22), which built-in spindle motor directly drives the tap (14) to rotate without a transmission mechanism, and which other motor drives the tap (14) with the built-in spindle motor (12) to proceed along a longitudinal direction (Z), the two motors (12, 22) are synchronously controlled, and the difference between a commanded rotational speed output to the built-in spindle motor (12) from a synchronous control unit (36) and an actual rotational speed of the built-in spindle motor detected by a detector (16) is calculated by a difference calculator (32), and an alarm is output, for example, by a light-emitting diode (40), when the difference is higher than a prescribed value. Thereby, a high-speed tapping can be effected, the number of defective products can be reduced, and the threads accurately tapped.

Claims

1. An apparatus for confirming movement of a tap when rigid tapping with a machine tool having a built-in spindle motor for directly driving a spindle to rotate and a Z-axis motor for driving the spindle to move linearly along an axis of the spindle, comprising:

a detecting means for detecting a rotation of said spindle;

a spindle control means for outputting a signal to control a rotation of said spindle motor according to a signal output from said detecting means;

a Z-axis control means for outputting a signal to control a rotation of said Z-axis motor;

a synchronous control means for outputting each synchronous signal to said spindle control means and said Z-axis control means, respectively; and

a judgement means for judging a follow-up ability of said spindle motor, by comparing a prescribed reference signal with a signal of a rotational error of said spindle calculated by said spindle control means, using the synchronous signal from said synchronous control means and the signal from said detecting means.