JPS63162157A - Grinding machine - Google Patents

Abstract

PURPOSE:To prevent a grindstone from being broken by providing a control system allowing the activation of the grindstone only when the signal detecting the zero rotation of the grindstone is on and controlling the grindstone not to be angle-activated during its inertial rotation until the rotation becomes zero. CONSTITUTION:A zero rotation detector 11 is connected between a pulse generator 5 and a computer control device 1, and the detector 11 detects that the rotation of a grindstone is stopped based on a speed detection signal S6 and outputs a zero rotation signal S11. The control device 1 ignores a grindstone activating signal S2 generated by the action of a worker not to rotate a grindstone motor 4 if the zero rotation signal S11 is off. Accordingly, the quick deceleration due to the re-activation during the inertial rotation of the grindstone which may be caused by the power outage or emergency stop operation is prevented, and a safe grinding machine with no crack of the grindstone can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to a grinding machine equipped with a grinding wheel rotation speed control function, and relates to a grinding machine that prevents the grinding wheel from being damaged due to starting during rough rotation of the grinding wheel.

<Prior Art> FIG. 2 is a block diagram showing a typical conventional grinding machine of this type. In the figure, reference numeral 1 denotes a computer control device, which is equipped with data input means such as machining conditions and operator instructions, and also has a function to control various output signals from these input data to perform desired grinding. are doing.

Sl is a base control signal which is the base of various data, and S2 is a motor start signal, both of which are output signals of the computer control device 1 and serve as input signals to the grindstone motor driver 3. 2 is a D/A converter which outputs a digital speed command signal S3 which is an output signal from the computer control device 1.
is converted into an analog signal and an analog speed command signal S4 is output to the grindstone motor driver 3. The grindstone motor driver 3 receives a base control signal 31. If the activation signal S2 is ON, a motor drive command S5 determined by an analog speed command signal S4 and a speed detection signal S6, which will be described later, is output. Reference numeral 4 denotes a grindstone motor, and a fixing flange 6 for fixing the grindstone 7 is attached to its output shaft. Reference numeral 8 denotes a movable flange for pressing and fixing the grindstone 7 against the fixed flange. A pulse generator 5 is mechanically connected to the rotating shaft of the grindstone motor 4 and outputs a speed detection signal S6.

Next, regarding the starting and stopping of the grinding wheel in a grinding machine with such a configuration, the grinding wheel is normally started using the pace control signal S1.
, turn on the start signal S2 and output the analog speed command signal s4.
Gradually increase from zero to achieve the desired rotational speed. Similarly, when stopping, the analog speed command signal S4 is gradually lowered to zero, or the base control signal S1 is turned OFF to cause a free run stop (natural rotation stop). That is, the rotation of the grindstone is controlled to provide gentle acceleration or deceleration. This means that the grinding wheel has a fixed flange 6 and a movable flange 8.
Because the method of fixing the grinding wheel with scissors is used, if the grinding wheel, which has a large inertia, is suddenly accelerated or decelerated, the contact surface between the flange and the grinding wheel may slip, causing the grinding wheel to crack.

<Problems to be Solved by the Invention> In a conventional grinding machine, for example, when a power outage occurs, the pace control signal S1 is turned off, so the grinding wheel rotates in free run and usually continues to rotate for several minutes. If the power outage is restored during this rational rotation, it will be possible to start up again. At this time as well, a command is output from the computer control device 1 to the grindstone motor driver 3 to gradually increase the rotation of the grindstone motor from zero by the operator's operation, in the same way as when the grindstone rotation is stopped.

As a result, the grinding wheel motor during free running is under control.
Since the grindstone motor starts from a zero command even though it is still rotating, a deceleration torque is generated in the free-running grindstone motor to achieve the zero rotation commanded by the analog speed command signal S4. Although this deceleration torque varies depending on the speed during free running, the performance of the grindstone motor 4 and the grindstone motor driver 3, etc., the torque may be sufficient to generate a gap between the flange and the grindstone 7 and cause the grindstone to crack. The way to solve this problem is for the operator to confirm that the grinding wheel has completely stopped before restarting it.

The tightening of the O grindstone increases the force.

θ Use a motor/motor driver/bar with low deceleration torque.

Both of these are considered undesirable for the following reasons.

is unreliable because it relies on operator confirmation.

The tightening torque for O is determined by the grindstone, and if the tightening torque is exceeded, the grindstone may crack due to the tightening force.

With θ, heavy grinding cannot be performed and the performance as a grinder deteriorates.

In any case, a breakage of the whetstone is not only economical, but also has the potential to cause extremely dangerous personal injury, and must be prevented at all costs under any circumstances.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a grinding machine that can reliably prevent sudden deceleration that could lead to damage to the grindstone, regardless of the operation.

Means for Solving the Problems> In order to solve the above problems and achieve the purpose, the present invention provides a detection means for detecting the zero rotation of the grindstone, and enables the grindstone to be started only when this signal is ON. It is characterized by a control method.

ζ Function By taking such measures, restarting of the grinding wheel during its rational rotation, which may occur due to a power outage or emergency stop operation, can be controlled so that it will not restart until it reaches zero rotation, thereby eliminating the cause of grinding wheel cracking. This makes it possible to prevent sudden deceleration.

=Example> The present invention will now be described in detail with reference to FIG. In Fig. 1, 1 is a computer control device, 2 is a D/A converter, 3 is a grinding wheel motor driver, 4 is a grinding wheel motor, 5 is a pulse generator, 6 is a fixed flange, 7 is a grinding wheel, and 8 is a movable 7 lunge. be. In addition, Sl is a base control signal, S2 is a start signal, S3 is a digital speed command signal, and S4
is the analog speed command signal, S5 is the motor drive command,
S6 is a speed detection signal.

A zero rotation detector 11 is connected between the pulse generator 5 and the computer control device 1. This zero rotation detector 11 detects that the rotation of the grindstone has stopped based on the speed detection signal S6, and a zero rotation signal Sll is generated as an output signal of this zero rotation detector 11.

By turning off the zero rotation signal 311, that is, by not rotating the grindstone motor 4, the computer control device 1 operates to ignore the grindstone start signal S2 generated by the operator's operation.

<Effects of the Invention> As detailed above, the present invention provides a zero rotation detector for detecting zero rotation of a grindstone, inputs a zero rotation signal, which is an output signal of the zero rotation detector, to a computer control device, The computer control device enables the operator's operation of the grindstone start signal only when this signal is ON (zero grindstone rotation). It is possible to obtain a grinding machine which prevents deceleration and is free from cracking of the grinding wheel, which is safe and which is economically improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, and FIG. 2 is a conventional block diagram. In the figure, 1 is a computer control device, 2 is a pulse generator, and 11 is a zero rotation detector.

Claims (1)

[Claims] A grinding machine that processes a workpiece by rotating a grinding wheel, and is equipped with a detection means for detecting zero rotation of the grinding wheel, and a control means for starting the grinding wheel only when this zero rotation signal is input.