JPH0573548B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a grinding abnormality detection device for a grinding machine of the type that corrects a rotary grindstone using a rotary dress.

(Prior Art) In a grinding machine equipped with a rotary grindstone, grinding causes wear and deformation of the grindstone, so after grinding a predetermined number of times, it is necessary to correct the grindstone using a rotary dress or the like. When the grindstone is dressed, the grindstone becomes clogged, so even though the grinding power (rotational load of the grindstone) during the first grinding after dressing is normal grinding operation. It is known that the value becomes larger than the grinding power during the second and subsequent grinding.

For this reason, in conventional grinding abnormality detection devices for grinding machines, the reference value for determining the presence or absence of grinding abnormality is set to a value higher than the peak value of the grinding power during the first grinding after dressing. When the grinding power of the grinding machine becomes larger than this reference value, a grinding abnormality signal is generated. This is because if the reference value is not set in this manner, a grinding abnormality signal will be issued even if the first grinding after dressing is performed normally.

(Problems to be solved by the invention) As mentioned above, in the conventional grinding abnormality detection device,
The reference value for determining the presence or absence of grinding abnormality is set to a value higher than the peak power value during the first grinding, so even if a grinding abnormality occurs in the grinding value after the second grinding, grinding will not continue. An abnormal signal may not be generated.

Therefore, an object of the present invention is to provide a grinding abnormality detection device for a grinding machine that generates a grinding abnormality signal when the grinding power of the grinding machine exceeds a preset reference value, which The reference value for grinding and the reference value for the second and subsequent grinding are set separately, and appropriate grinding abnormalities can be detected not only during the first grinding after dressing, but also during the second and subsequent grinding. An object of the present invention is to provide a grinding abnormality detection device for a grinding machine that is capable of emitting a signal.

(Means and effects for solving the problem) In order to achieve the above-mentioned object, the present invention provides a first reference value that is higher than the peak value of rotational power during normal operation during the first grinding after dressing processing. The presence or absence of an abnormality is determined based on the second reference value, and during the second and subsequent grinding, the presence or absence of an abnormality is determined based on a second reference value that is lower than the first reference value. Specifically, in a grinding abnormality detection device for a grinding machine that generates a grinding abnormality signal when the grinding power of the grinding machine exceeds a preset reference value, the grinding wheel of the grinding machine is in the grinding operation. a grinding power detector for detecting rotational load in the grinding wheel; a first reference value setter having a first reference value set therein for detecting an abnormality in the first grinding after dressing the grindstone; A second reference value setter is set with a second reference value lower than the first reference value in order to detect abnormalities in grinding after the first grinding, and the first grinding after dressing the grindstone. a determiner that determines whether or not the grinding power is the same, and when it is determined by the determiner that this is the first grinding after dressing the grindstone, the output of the grinding power detector and the first reference value setter; and, at other times, compares the output of the grinding power detector and the output of the second reference value setter to determine whether or not there is a grinding abnormality. It is structured like this.

(Example) Examples of the present invention will be described below based on the attached drawings.

FIG. 1 shows the relationship between the number of times of grinding performed by the grinding machine and the grinding power (rotational load on the rotary grindstone) after correction processing using the rotary dress of the rotary grindstone. As is clear from the figure, the first grinding immediately after dressing requires greater grinding power than the second and subsequent grinding. This is thought to be because the dressing causes clogging and the like in the rotating grindstone, which generates a large frictional force when it comes into contact with the workpiece, thereby increasing the rotational load on the rotating grindstone. Furthermore, the grinding power from the second dressing onwards is almost the same until the next dressing process, and this is thought to be because the clogging of the grindstone is cleared during the first grinding.

FIG. 2 shows a first embodiment of the grinding abnormality detection device of the present invention. In the figure, 1 is a rotating grindstone, and 2 is a workpiece. The rotary grindstone 1 is rotationally driven by a motor 3, and the motor 3 is equipped with a grinding power detector 4.
are connected to each other, and power is supplied to the motor 3 via this grinding power detector 4. A grinding power detector 4 detects the rotational load of the rotary grindstone 1 during the grinding operation as the power required by the motor 3. On the other hand, a first reference value setter 5 and a second reference value setter 6 are provided which output a reference value for comparison with the output signal of the detector 4. The first reference value setter 5 sets a first reference value after dressing the grinding wheel 1 to detect an abnormality in the first grinding operation.
Output B ₁ (see Figure 1). Further, the second reference value setter 6 is configured to set a second reference value after dressing the grinding wheel 1 in order to detect abnormalities in the second and subsequent grinding operations.
Output B ₂ (see Figure 1). As is clear from FIG. 1, the first reference value _B1 is set to a value higher than the peak value of the first grinding power by a predetermined amount,
The second reference value _B2 is set to a value higher than the peak value of the second grinding power by a predetermined amount. and,
The first reference value _B1 is set higher than the second reference value _B2 by G (G>0).

The first reference value setting device 5 is the first reference value setting device 5 of the comparison signal switching device 7.
The second reference value setter 6 is connected to the second input terminal 7b of the switch 7. Then, the output end 7c of the switch 7 and the grinding power detector 4
are connected to a power comparator 8, respectively, and the power comparator 8 is connected to an abnormal output detector 9. This comparator 8 and detector 9 constitute a grinding abnormality discriminator.

10 shows a control circuit of the grinding machine, and control circuit 1
0 is provided with an alarm indicator 11 that generates a grinding abnormality signal and a stop signal generator 12 that applies an emergency return and stops the grinding machine when a grinding abnormality occurs. The stop signal generator 12 may be configured to stop the grinding machine by stopping the cycle at the end of the cycle, without immediately setting an emergency return after the occurrence of a grinding abnormality.

A counter 13 outputs a contact switching signal to the switching device 7. The counter 13 is the control circuit 1
It is reset by receiving a dressing completion signal from 0, and then counts the number of times of grinding.

The counter 13 and the control circuit 10
A determining device is configured to determine whether or not this is the first grinding after dressing.

The operation of the first embodiment will be explained. First, a dressing completion signal is sent from the control circuit 10 to the counter 13.
When the counter 13 is outputted, the counter 13 resets itself and sends a signal to the switch 7 to connect its first input terminal 7a and output terminal 7c.
As a result, the first reference value B ₁ is inputted to the comparator 8 from the setter 5 . When the grinding power during the first grinding is higher than the first reference value _B1 , the detector 9 detects this and issues a signal to the control circuit 10, which starts the alarm display 11 and the stop signal generator 12. let The functions of the display 11 and generator 12 are as described above.

Next, when the first grinding operation is completed, the counter 13 detects this and issues a signal to the switch 7 to connect the first input terminal 7b to the output terminal 7c. As a result, the second reference value B ₂ is input to the comparator 8 from the second reference value setting device 6 . Therefore,
When the second and subsequent grinding starts and the peak value of the grinding power during the third grinding exceeds the second reference value _B2 , for example as shown by the broken line in FIG. A signal is issued to circuit 10. As a result, as in the case described above, the alarm display 11,
The stop signal generator 12 is activated.

FIG. 3 shows a second embodiment of the present invention, in which the same components as in the previous embodiment are given the same reference numerals, and their explanation will be omitted.

In this embodiment, the second reference value _B2 used during the second and subsequent grinding is set not as an absolute value but based on the peak value of the grinding power during the first grinding. At the point. That is, in order to satisfy such a function, as shown in FIG. It is interposed in.

To explain the operation of the second embodiment, first, when the dressing process is completed, the first input terminal 7a and the output terminal 7 of the switching device 7 are connected in response to a signal from the counter 13, as in the previous embodiment. hand,
First reference value from first reference value setter 5 to comparator 8
B ₁ is input. The determination of the presence or absence of the first grinding abnormality is performed based on this first reference value _B1 in the same manner as in the first embodiment. At this time, counter 1
3 turns on the switch 14, and the peak value of the grinding power during the first grinding is stored in the circuit 15. Then, the override 16 subtracts a predetermined amount from this peak value at a preset ratio and inputs that value to the second reference value setter ₆ as the second reference value B2. And the second
The presence or absence of grinding abnormality after the first grinding is determined based on the second reference value _B2 set in this way, in the same manner as in the first embodiment.

In this second embodiment, variations in the precision of the dressing process are absorbed, and it is possible to further improve the accuracy of determining abnormalities in the second and subsequent grinding operations.

(Effects of the Invention) As explained above, according to the grinding abnormality detection device of the present invention, after dressing, during the first grinding and during the second grinding,
Determine whether or not there are any abnormalities in grinding after the first grinding.
Since the determination is made based on separate reference values, it is possible to greatly improve the accuracy of determining abnormalities in grinding.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between the grinding power of the grinder and the number of times of grinding. FIG. 2 is a block diagram showing the configuration of a first embodiment of the present invention. FIG. 3 is a block diagram showing the configuration of a second embodiment of the present invention. 1... Rotating grindstone, 2... Workpiece, 3... Motor, 4... Grinding power detector, 5... First reference value setter, 6... Second reference value setter, 7... Comparison Signal switch, 8... Power comparator, 9... Abnormal output detector, 10... Control circuit.

Claims (1)

[Scope of Claims] 1. A grinding abnormality detection device for a grinding machine that generates a grinding abnormality signal when the grinding power of the grinding machine exceeds a preset reference value, comprising: a grinding power detector that detects a rotational load during operation; a first reference value setting device that is set with a first reference value for detecting an abnormality in the first grinding after dressing the grindstone; a second reference value setter in which a second reference value lower than the first reference value is set to detect abnormalities in the second and subsequent grinding; and a first grinding after dressing the grindstone. a determination device that determines whether or not the grinding power is the same, and when the determination device determines that it is the first grinding after dressing the grindstone, the output of the grinding power detector and the first reference value setting. a grinding abnormality discriminator that determines whether there is a grinding abnormality by comparing the output of the grinding power detector and the output of the second reference value setting device at other times. A grinding abnormality detection device characterized by: