JP3850780B2 - Workpiece supply abnormality detection method and workpiece supply abnormality detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a workpiece supply abnormality detection method and apparatus for detecting an abnormality in the supply of a workpiece when continuously feeding the workpiece to be fed by a centerless grinding machine.
[0002]
[Prior art]
When a workpiece is continuously processed by through-feed grinding with a centerless grinder, the workpiece is generally continuously supplied using a parts feeder. At that time, due to factors such as mixing of workpieces with different diameters, insufficient amount of workpieces in the parts feeder (occurs frequently in the case of a production method in which an operator inputs workpieces), contamination of foreign matters (dust etc.), etc. If a failure occurs in the parts feeder, the supply of the workpiece becomes abnormal (discontinuous), and the accuracy of the finished dimensions varies.
[0003]
In addition, as a cause of the variation in dimensional accuracy due to the supply abnormality of the workpiece, for example, a change in the processing heat capacity acting on the grinding wheel, a pinch-out effect, and the like are conceivable. In addition, it is impossible to accurately determine the supply abnormality of the workpiece by simply checking the number of workpieces on the discharge side.
[0004]
For this reason, conventionally, a sensor for detecting a workpiece is attached to the supply side to detect a supply abnormality of the workpiece. This prior art is a conventional technique and does not relate to a specific known invention.
[0005]
[Problems to be solved by the invention]
However, in the conventional workpiece supply abnormality detection method, there is a problem that the workpiece supply abnormality cannot be reliably detected due to the effects of sensor responsiveness, workpiece behavior, self-vibration of the parts feeder, and the like. In particular, the faster the workpiece feed rate (for example, 5 m / min. Or more), the smaller the workpiece, and the shorter the workpiece, the higher the rate of false judgment by the sensor, and the abnormal supply of the workpiece. It tends to be difficult to reliably detect.
[0006]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional problems, and it is an object of the present invention to provide a workpiece supply abnormality detection method and apparatus capable of reliably detecting a workpiece supply abnormality continuously supplied to a through-feed centerless grinding machine. And
[0007]
[Means for Solving the Problems]
The method according to the present invention is a workpiece supply abnormality detection method for detecting an abnormality in the supply of a workpiece when continuously feeding and grinding a workpiece between a grinding wheel of a centerless grinder and a control wheel. And measuring a current value that changes according to an increase or decrease in the number of the workpieces per grinding wheel width of the grinding wheel of the driving motor that drives the grinding wheel or the adjusting wheel, and the measured current value is calculated as the workpiece. Compared with a set value that is set slightly lower than the lower limit value of the load current of the drive motor at the time of normal supply , it is determined that the workpiece supply is abnormal when the measured current value falls below the set value. Then, when the measured current value greatly falls below the set value, the work piece before and after is discontinued .
[0008]
The present invention apparatus, the workpiece supply abnormality detection for detecting an abnormality in supply of said workpiece at the time of grinding feed through by continuously feeding the workpiece between the centerless grinding machine of the grinding wheel and the regulating wheel the apparatus met, the driving motor for driving the grinding wheel or the regulating wheel, a measuring means for measuring a current value which varies with increase or decrease of the processing the number per grindstone width of the grinding wheel is measured by the measuring means A comparing means for comparing the measured current value with a set value set slightly lower than a lower limit value of the load current of the drive motor when the workpiece is normally supplied, and the measured current value is less than the set value. And determining means for determining that the supply of the workpiece is abnormal and determining that the preceding and following workpieces are interrupted when the measured current value is significantly below the set value .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a centerless grinding machine, on a bed 2, a grinding wheel 3, a grinding wheel driving motor 4 that rotationally drives the grinding wheel 3, an adjusting wheel 5, and an adjusting wheel drive that rotationally drives the adjusting wheel 5. A motor 6 is provided via a grinding wheel base 7 and an adjusting wheel base 8, respectively, and a blade 9 for supporting a workpiece W to be fed and ground between the grinding wheel 3 and the adjusting wheel 5 is provided. Yes.
[0010]
The workpieces W are aligned in a line by, for example, the parts feeder 10 and are continuously supplied between the grinding wheels 3 and 5 by the supply conveyor 11. In addition, the feed speed of the supply conveyor 11 is higher than the feed speed of the workpiece W between both the grindstones 3, 5, and continuous feeding between the both grindstones 3, 5 with the front and rear workpieces W in contact with each other. It has come to be. In addition, 12 is a discharge conveyor, and discharges the workpiece W after grinding.
[0011]
Reference numeral 13 denotes a workpiece supply abnormality detection device (hereinafter referred to as a supply abnormality detection device) having a function of detecting a supply abnormality (discontinuity) of the workpiece W by measuring a grinding load F applied to the grinding wheel driving motor 4. Have. As shown in FIG. 2, the supply abnormality detection device 13 includes a measuring unit 14 that measures a grinding load F applied to the grinding wheel driving motor 4, and a comparison unit 15 that compares the grinding load F with a predetermined set value S. Based on the comparison result of the comparison unit 15, the storage unit 16 that stores the set value S, the determination unit 17 that determines whether or not the supply of the workpiece W is abnormal, and the determination unit 17 includes the workpiece W When it is determined that the supply is abnormal, an informing means 18 for informing the fact is provided.
[0012]
The measuring means 14 has a function of measuring the power value, current value, etc. of the grinding wheel driving motor 4 as the grinding load F and measuring it. For example, when a three-phase motor is used for the grinding wheel driving motor 4, the power value or current value can be regarded as the grinding load F. If the grinding wheel drive motor 4 is driven via an inverter, the current change can be detected using the inverter as a detector. If not, an external wattmeter or the like can be used. What is necessary is just to catch a power change etc. as a detector.
[0013]
Further, when an AC servomotor is used for the grinding wheel drive motor 4, the AC servomotor itself can be used as a detector, and the torque fluctuation can be regarded as the fluctuation of the grinding load F.
[0014]
In the embodiment, the grinding load F applied to the grinding wheel driving motor 4 is measured, but the load (grinding load F) applied to the adjusting wheel driving motor 6 may be measured. In that case, the present invention can be implemented in substantially the same manner as in the embodiment.
[0015]
The storage means 16 has a function of storing a set value S that is slightly smaller than the lower limit value of the grinding load F when the workpiece W is normally supplied. The setting value S may be experimentally obtained and input externally, or setting means for automatically setting the setting value S according to the size, material, processing conditions, etc. of the workpiece W may be provided. . The comparison unit 15 has a function of comparing the grinding load F measured by the measurement unit 14 with the set value S stored in the storage unit 16.
[0016]
The determination unit 17 refers to the comparison result of the comparison unit 15 and determines that the supply of the workpiece W is normal when the grinding load F exceeds the set value S, and the grinding load F is the set value. It has a function to determine that the supply of the workpiece W is abnormal when it is below S, and a function to transmit an abnormal signal to the notification means 18 when it is determined to be abnormal.
[0017]
The notification means 18 is composed of, for example, a warning light, a buzzer, etc., and operates on the condition that an abnormality signal is received from the determination means 17, and indicates that the supply of the workpiece W is abnormal. Etc. are to be notified.
[0018]
Next, a workpiece supply abnormality detection method using the supply abnormality detection device 13 having the above configuration will be described with reference to FIGS. FIG. 4 shows the fluctuation (torque fluctuation) of the grinding load F applied to the grinding wheel driving motor 4 when the workpiece W is subjected to feed grinding using an AC servo motor as the grinding wheel driving motor 4. It is a graph.
[0019]
When starting the supply abnormality detection of the workpiece W, first, the measuring means 14 starts the measuring step (S10) (S11). Note that the start and end of the measurement step (S10) may be linked to the start and end of the driving of the grinding wheel drive motor 4 or the feed of the workpiece W, or triggered by the operation of the operator or the like. Also good. In the measuring step (S 10), the measuring means 14 measures the grinding load F applied to the grinding wheel driving motor 4 and transmits the data to the comparing means 15.
[0020]
In the comparison step (S12), the comparison means 15 that has received the grinding load F data from the measurement means 14 compares the grinding load F with the set value S stored in the storage means 16, and the comparison result. Is sent to the determination means 17.
[0021]
Note that a set value S is set in advance when the supply abnormality of the workpiece W is detected. As the setting process, for example, the fluctuation of the grinding load F in a state where the workpiece W is normally continuously supplied is measured, a value slightly smaller than the lower limit value is set as the set value S, and the storage means 16. You just have to remember it.
[0022]
In the determination step (S13), the determination unit 17 that has received the comparison result data from the comparison unit 15 determines whether or not the supply of the workpiece W is abnormal based on the comparison result. At this time, when the grinding load F is less than the set value S, the determination means 17 determines that the supply of the workpiece W is abnormal (Yes). Incidentally, when the supply of the workpiece W becomes discontinuous due to a defect on the supply side such as clogging of the parts feeder 10 and the supply of the workpiece W becomes discontinuous, the front and rear workpieces W are in contact with each other. Compared to the case, the number of workpieces W per grinding wheel width decreases, and the grinding load F applied to the grinding wheel driving motor 4 falls below the set value S as shown in FIGS. Can be determined to be abnormal. It should be noted that the portions where the grinding load F is greatly reduced, such as E and G in FIG. 4, are largely interrupted between the front and rear workpieces W, for example, when the workpiece W no longer exists between the grinding wheels 3 and 5. Indicates the state.
[0023]
When the determination unit 17 determines that the supply of the workpiece W is abnormal, the determination unit 17 transmits an abnormality signal to the notification unit 18. In the notification step (S14), the notification unit 18 that has received the abnormal signal from the determination unit 17 starts to operate, and notifies the operator and the like that the supply of the workpiece W is abnormal.
[0024]
On the other hand, when the grinding load F exceeds the set value S, the determination means 17 determines that the supply of the workpiece W is normal (No) in the determination step (S13), and the notification step (S14) is performed. skip. Incidentally, when the front and rear workpieces W are in contact and normally continuously supplied, the number of workpieces W per whetstone width is kept constant at a maximum value, for example, as shown in FIGS. Since the grinding load F exceeds the set value S and is maintained substantially constant, it is possible to determine that the supply of the workpiece W is normal.
[0025]
Thus, since the grinding load F responds sensitively to the number of workpieces W per wheel width, abnormal supply of the workpieces W can be detected with high reliability.
[0026]
Then, regardless of the determination by the determination means 17, the measurement means 14 confirms whether or not to end the measurement process (S10) (S15). If not (No), the comparison process (S12) is performed. Return and repeat the above control. When the measurement step (S10) is ended (Yes), the measurement unit 14 ends the measurement of the grinding load F (S16), and the supply abnormality detection of the workpiece W is ended. Examples of the termination condition of the measurement step (S10) include stop of the grinding wheel driving motor 4, termination of the feed of the workpiece W, operator operation, and the like.
[0027]
It should be noted that, when the determination means 17 once makes an abnormality determination and the notification means 18 notifies the fact, the determination means 17 notifies when the grinding load F increases and the determination means 17 makes a normal determination. A notification release signal may be transmitted to the means 18 to stop the notification. Further, the notification unit 18 may be provided with a timer or the like, and the notification unit 18 may notify only for a predetermined time, or may be provided with an operation switch for releasing notification that can be operated by the operator.
[0028]
Moreover, K and L of FIG. 4 have shown the condition in which the workpiece W is not sent between both the grindstones 3 and 5, ie, what is called a no-load state. In such a case, the grinding load F is naturally lower than the set value S, but it may be set so that the notification means 18 does not perform notification, such as providing a lower limit value of the grinding load F that performs notification. K ′ indicates the situation in which the front side of the workpiece W is entering between the grinding wheels 3 and 5, and L ′ indicates the situation in which the remaining workpiece W is being pushed out between the grinding wheels 3 and 5, respectively. The same applies to these cases.
[0029]
As shown in FIG. 4A, when the grinding load F is fluctuating greatly and the grinding load F is frequently lower than the set value S, the supply of the workpiece W is very unstable and frequently occurs. It can be seen that the discontinuity of the workpiece W has occurred. 4B, when the grinding load F is stable above the set value S, it can be seen that the workpiece W is stably and continuously supplied. .
[0030]
The workpiece supply abnormality detection method of this embodiment includes a measuring step (S10) for measuring the grinding load F applied to the grinding wheel drive motor 4 and a comparison step (S12) for comparing the grinding load F with a predetermined set value S. And a determination step (S13) for determining whether or not the supply of the workpiece W is abnormal based on the comparison result, the workpiece W is provided by a sensor provided on the supply side of the workpiece W. Compared with the method for detecting the supply abnormality, the detection with higher reliability can be performed, and the method is sufficiently applicable to the monitoring of the production status. Accordingly, it is possible to immediately cope with the supply abnormality of the workpiece W, the dimensional management of the workpiece W is facilitated, and a large number of defective products due to a supply abnormality detection error can be prevented.
[0031]
Including a setting step of setting a set value S based on the lower limit value of the grinding load F when the workpiece W is normally supplied, and supplying the workpiece W when the grinding load F falls below the set value S Therefore, it is possible to easily detect the supply abnormality of the workpiece W.
[0032]
When it is determined that the supply of the workpiece W is abnormal, the notification step (S14) for notifying the fact is included, so that the operator can immediately cope with the supply abnormality of the workpiece W.
[0033]
As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited to embodiment, A various change is possible in the range which does not deviate from the meaning.
[0034]
In the embodiment, the front and rear workpieces W are brought into contact with each other and are continuously supplied between the grindstones 3 and 5. However, the workpiece W is intermittently provided at a constant interval between the front and rear workpieces W. The present invention can also be applied to the case of continuous supply. That is, when the interval between the front and rear workpieces W increases, the number of workpieces W per grinding wheel width decreases and the grinding load F decreases, so that a supply abnormality is determined in substantially the same manner as in the embodiment. It is possible. Further, when the interval between the preceding and following workpieces W becomes small due to excessive supply of the workpiece W, the number of workpieces W per grinding wheel width increases and the grinding load F rises. By setting the set value S ′ based on the upper limit value of the grinding load F when it is normally supplied at regular intervals, when the grinding load F exceeds the set value S ′, it is excessive. It is possible to detect supply abnormality of the workpiece W due to supply.
[0035]
In the embodiment, when the determination unit 17 determines that the supply of the workpiece W is abnormal, the notification unit 18 such as a warning light or a buzzer notifies that fact. For example, the supply is abnormal. If it is determined, the grinding by the centerless grinding machine 1 may be stopped. When a supply abnormality is notified, an appropriate countermeasure may be taken according to each production method.
[0036]
Further, a monitor that displays the fluctuation of the grinding load F may be provided. In this case, the operator may determine whether or not the supply of the workpiece W is abnormal by looking at the monitor. Furthermore, a storage means for storing the change over time of the grinding load F or a recording means for recording by printing or the like may be provided. In this case, the accuracy of the inspection is improved by focusing on the workpiece W that has been ground when the supply is abnormal or unstable based on the stored or recorded data. Can be reduced.
[0037]
In the embodiment, it is determined that the supply of the workpiece W is abnormal when the grinding load F falls below the set value S. However, the length of the workpiece W, the feed speed, the allowable error, and the grindstone width are determined. An appropriate time may be set according to the above, and when the grinding load F falls below the set value S longer than that time, it may be determined that the supply of the workpiece W is abnormal.
[0038]
【The invention's effect】
The method of the present invention measures a current value that varies depending on the increase / decrease in the number of workpieces per grinding wheel width of a grinding wheel or driving motor that drives a grinding wheel, and supplies the measured current value to a normal supply of the workpiece. Compared with the set value set slightly lower than the lower limit of the load current of the drive motor at the time, when the measured current value falls below the set value, it is determined that the workpiece supply is abnormal, and the measured current value When the value is significantly below the set value, the front and rear workpieces are interrupted, so that the supply abnormality of the workpiece can be reliably detected.
[0041]
The present invention apparatus, the driving motor for driving the grinding wheel or the regulating wheel, a measuring means for measuring a current value that varies with changes in processing the number per grindstone width of the grinding wheel, the current value measured by the measuring means Comparison means to compare with the set value set slightly lower than the lower limit of the load current of the drive motor during normal supply of the workpiece, and abnormal supply of the workpiece when the measured current value falls below the set value And a means for determining that the front and rear workpieces are interrupted when the measured current value is significantly below the set value , the workpiece supply abnormality can be reliably detected.
[Brief description of the drawings]
FIG. 1 is a plan view of a centerless grinding machine showing an embodiment of the present invention.
FIG. 2 is a block diagram of a workpiece supply abnormality detection device showing an embodiment of the present invention.
FIG. 3 is a flowchart of a workpiece abnormality detection method showing an embodiment of the present invention.
FIG. 4 is a graph of grinding load variation showing an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Centerless grinding machine 3 Grinding wheel 4 Grinding wheel drive motor 5 Adjusting wheel 6 Adjusting wheel drive motor 13 Workpiece supply abnormality detection device 14 Measuring means 15 Comparison means 17 Determination means

Claims (4)

A workpiece supply abnormality detection method for detecting an abnormality in the supply of the workpiece when continuously feeding and feeding through a workpiece between a grinding wheel of a centerless grinder and an adjustment wheel, the grinding A current value that changes due to increase / decrease in the number of workpieces per grinding wheel width of the grinding wheel of the driving motor that drives the grinding wheel or the adjusting wheel is measured, and the measured current value is measured when the workpiece is normally supplied. Compared with a set value set slightly lower than the lower limit value of the load current of the drive motor, when the measured current value falls below the set value, it is determined that the workpiece supply is abnormal, and the measured A workpiece supply abnormality detection method characterized by discontinuing a workpiece before and after the current value greatly falls below the set value . Workpiece supply abnormality detection method according to claim 1, the higher the factory to set the pre Ki設 value characterized the early days free. Workpiece supply abnormality detection method according to claim 1 or 2, characterized in the Turkey it is reported to the effect that the Niso when it is determined that the supply abnormality. Centerless met workpiece workpiece supply abnormality detecting device for detecting a supply abnormality of the workpiece at the time of grinding feed through continuously supplied between the grinding machine of the grinding wheel and the regulating wheel, wherein A measuring means for measuring a current value that changes due to an increase or decrease in the number of the workpieces per grinding wheel width of the grinding wheel of a driving motor that drives the grinding wheel or the adjusting wheel, and a current value measured by the measuring means , Comparison means for comparing with a set value set slightly lower than the lower limit value of the load current of the drive motor at the time of normal supply of the workpiece, and when the measured current value falls below the set value, the workpiece A workpiece supply abnormality detection device comprising: a determination unit that determines that the preceding and following workpieces are interrupted when the measured current value greatly falls below the set value .

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