JPS6327722B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a backlash correction method for a numerical control device that corrects backlash occurring in a processing machine such as a machine tool or an industrial machine.

Prior to explaining the present invention, a method for measuring the amount of backlash defined by JIS and the phenomenon of machine ejection will be briefly explained using FIGS. 1 to 3.

In Figure 1, point a is the starting position of the machine,
Point b is a point moved by, for example, +100mm by a rapid traverse command, and point c is further moved by 100mm by a rapid traverse command.
Assuming that the moved point, point d, is a point returned by -100 mm from point c by a fast forward command, the dial gauge is preset at point b, and the difference in the reading on the dial gauge when returned to point d is taken as the backlash amount. There is.

By the way, when a machine is moved by rapid traverse, the gear 1 on the machine side and the gear 2 on the feed motor side usually stop with a backlash shown by α, as shown in Fig. 2, but depending on the machine, As shown in FIG. 3, there is a case where the gear 1 on the machine side stops in a state where it appears to be pushed away from the gear 2 on the motor side by an amount indicated by β.

Conventionally, the backcrush correction that occurs in processing machines such as machine tools or industrial machines controlled by numerical control devices is based on the amount of backlash measured by the method shown in FIG. The back-crush amount for β) is set in a storage device such as an IC memory, and whenever the moving direction of the processing machine changes, the above-mentioned back-crush is unconditionally applied to the actual movement command value, whether it is rapid traverse or cutting feed (low-speed traverse). This is done by increasing the amount.

In this way, the measured backlash amount is
In processing machines where the push-off phenomenon occurs during rapid traverse,
The setting value (α−β) is smaller than the original backlash amount by the amount of push-out. Therefore, if the set values are corrected as they are, when cutting a perfect circular contour using a cutting feed that does not cause the push-off phenomenon, a step in the cut will occur near the switching point where the push-off phenomenon occurs, and the machining accuracy will decrease. There was a drawback.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and when the power transmission means is moved at a low speed and then moved in a direction opposite to the direction of the low speed feed, the power transmission means has a predetermined first backlash. When the power transmission means is moved in the opposite direction to the high-speed feeding direction, an ejecting phenomenon occurs in the power transmission means, and a second buck-crushing amount is generated which is smaller than the first buck-crushing amount. In a device that controls a machine that produces The determining means determines whether the feed is high-speed feed or low-speed feed, and if the determination result is high-speed feed, correcting the buckle of the power transmission means with the second buckle amount, and It is an object of the present invention to provide a backlash correction method for a numerical control device that can improve machining accuracy near the backlash operation by correcting the backlash of the power transmission means using the first backlash amount when the feed is at a low speed. This is the purpose.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 4, reference numeral 11 indicates a determination circuit for determining whether or not the previous movement command was for fast forwarding; 12;
is a determination circuit that determines whether the cutting feed is hot or not;
Reference numeral 13 denotes a control circuit which sets the outputs of the discrimination circuits 11 and 12 to the flip-flop 14 immediately before starting backlash correction. Reference numeral 15 denotes a storage device for storing the set value of the backlash (first backlash amount α) measured in the example shown in FIG. or β), 17 is an AND circuit, and 18 is an OR circuit.

For example, if a gear is moved by cutting feed, then moved back in the opposite direction by rapid traverse, and then returned in the opposite direction by cutting feed, first, the gear is moved from cutting feed to rapid traverse. At the point where the switching occurs, the flip-flop 14 is reset by the discrimination circuit 12 and the control circuit 13, and the amount of backlash is corrected by the amount set in the storage device 15. Next, at the point where rapid feed is switched to cutting feed, the flip-flop 14 is set by the discrimination circuit 11 and the control circuit 13, and the storage device 1 is set.
It is corrected by the setting amount of 6.

As described above, the present invention causes the power transmission means to produce a predetermined first backlash amount when low-speed feeding is performed and then moved in the opposite direction to the low-speed feeding direction, and at the same time, high-speed feeding is performed and then the high-speed In a device for controlling a machine that causes a push-off phenomenon to occur in the power transmission means and generates a second amount of backlash smaller than the first amount of backlash when the device is moved in a direction opposite to the feeding direction, the power transmission means The first and second batch amounts of the means are stored in the storage means, and before the moving direction of the machine changes and the batch correction starts, it is determined whether the feed up to that point was high speed feed or low speed feed. is discriminated by the discriminating means, and if the discrimination result indicates high-speed feed, the backlash of the power transmission means is corrected by the second backlash amount, and if the result is low-speed feed, the backlash of the power transmission means is corrected by the first backlash amount. Since the bump crash of the power transmission means is corrected by the amount, even in the above-mentioned machines, the bump bump can be corrected with the correct correction amount, and therefore the machining accuracy of the workpiece can be improved. There is.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the method for measuring the amount of backlash of a machine according to JIS, Figures 2 and 3
The figures are diagrams for explaining a phenomenon in which the backlash of a machine is released, and FIG. 4 is a block diagram for explaining the backlash correction method according to the present invention. In the figure, 1 is a gear on the machine side, 2 is a gear on the motor side, 11 and 12 are a discrimination circuit, 13 is a control circuit, 14 is a flip-flop, 15 and 16 are storage devices, 17 is an AND circuit, and 18 is an OR circuit. be.

Claims (1)

[Claims] 1 When performing low-speed feeding and then moving in the opposite direction to the low-speed feeding direction, a predetermined first backlash amount is generated in the power transmission means, and at the same time, high-speed feeding is performed and then in the opposite direction to the high-speed feeding direction. The first and second portions of the power transmission means control a machine that, when moved, causes a push-off phenomenon to occur in the power transmission means and produces a second amount of backlash that is smaller than the first amount of backlash. The amount of backlash is stored in the storage means, and before the moving direction of the machine changes and the backlash correction is started, the determining means determines whether the feed up to that point is high-speed feed or low-speed feed, If the determination result is high-speed feed,
A backlash of a numerical control device characterized in that the backlash of the power transmission means is corrected by the second backlash amount, and when the feed is at a low speed, the backlash of the power transmission means is corrected by the first backlash amount. Correction method.