JPH10235538A - Anomaly detecting method for rotary tool and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary tool detecting method that is capable of properly detecting trouble with this rotary tool accurately at real time in a simple structure, and the device. SOLUTION: A threshhold value (high) of load in a normal condition of a drill and a threshhold value (low) of load in an abnormal condition both are stored in an operational means which incorporates a load value signal Xn from a load detecting means (S1), calculating a variation ΔXn in the load value and its standard deviation σΔxn (S2). In the case of an expression of Xn<ΔX bar-±3σΔx, it is so judged as a normal machining state, the threshhold value (high) is selected (S4), and it is compared with the load value Xn (S5). In this case of another expression of ΔXn>ΔX bar ±3σΔx, it is judged that the abnormal condition has occurred, and the threshhold value (low) is selected (S6), and it is compared with the load value Xn (S7). In the case where Xn exceeds each of these threshhold values (high and low), an anomaly detecting signal is outputted (S8).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting an abnormality of a rotary tool.

[0002]

2. Description of the Related Art Rotary tools such as drills, taps, milling machines, and end mills used in machining equipment such as machining centers, lathes, and milling machines wear with use.
Due to disturbance factors such as the cutting depth, the load such as thrust and torque applied to the rotary tool changes so as to increase. When a load equal to or more than the predetermined value is applied, damage occurs such as breakage of the rotary tool and loss of the blade. Therefore, in particular, when the machining apparatus is operated by a predetermined program to repeatedly machine a workpiece, it is necessary to detect an abnormality before the rotary tool is damaged and to prevent damage. Therefore, generally, a predetermined threshold value of the load of the rotating tool is set,
A load applied to the rotating tool is detected, and an abnormality of the rotating tool is detected by comparing a set threshold value with the detected value of the load.

By the way, the value of the load applied to the rotary tool is not steady, and as shown in FIG. 8, in a normal case where the load is worn with use, the load gradually increases after a predetermined number of machining. Will change. That is, the rate of change of the load applied to the rotary tool is relatively small. However, in particular, in the case of a rotary tool having a long length with respect to the diameter, such as the above-described drill or tap, the straightness of the workpiece to be machined is impaired as the end of the life of the rotary tool approaches, and the workpiece is bent. The workpiece enters the workpiece in the state, and the rate of change of the load applied to the rotary tool is relatively small, but the variation is large. On the other hand, in the case of a disturbance factor, the load applied to the rotary tool increases rapidly, and the rate of change of the load applied to the rotary tool increases. In other words, the time from when the load starts to increase so as to reach the damage level of the rotary tool is short.

For this reason, when the threshold value for comparison with the load is set high, the abnormality in the rotary tool is delayed due to the above-mentioned variation in load and a sudden rise. When the threshold value is set low, the frequency of changing the rotary tool increases. Therefore, various conventional techniques have been considered in order to appropriately set the threshold value in consideration of the variation in the detected load or a sudden increase.

The prior art is disclosed in Japanese Patent Application Laid-Open No. 61-192.
There is known a method for detecting an abnormality of a multi-blade tool disclosed in Japanese Patent Publication No. 449/449. In this method, a cutting force change pattern in the multi-edged tool is detected, and an autocorrelation coefficient is calculated from the detected cutting force change pattern and a delay pattern obtained by delaying the cutting force change pattern by a predetermined period. The autocorrelation coefficient is compared with a preset threshold value, and an abnormality of the multi-blade tool is detected based on the comparison result.

Another conventional technique is disclosed in Japanese Unexamined Patent Publication No.
A cutting tool damage detection device disclosed in Japanese Patent Application Publication No. 9554 is known. In this apparatus, a means for detecting a cutting load force, a cumulative average load force calculating means for calculating a cutting load force at the time of the latest predetermined number of cutting operations, and an output of the detection unit with respect to an output of the cumulative average load force calculating means And a comparison unit that compares the output of the variation ratio calculation unit with a set value, and a machine tool control device that stops the machine tool according to the output of the comparison unit. The set value (threshold value) to be compared with the output of the variation ratio calculating means by the comparing means differs depending on the machining conditions, the work material, and the like, and is determined by a cutting test or the like. Line 11 to column 13, line 13).

Further, as another conventional technique, Japanese Patent Laid-Open No.
BACKGROUND ART An abnormality prediction device for a rotary tool disclosed in Japanese Patent Application Publication No. 2011159 is known. In this apparatus, a cutting force detector provided on a holder for holding a rotary tool, and a calculation device for outputting a warning signal when a signal from the cutting force detector exceeds a predetermined threshold value, The apparatus detects the first spike signal each time cutting is performed, and sets a threshold value based on the cutting signal immediately before the detection of the spike signal. In this case, the torque signal and the thrust signal are stable immediately before the first spike-like signal is generated. And a predetermined multiple thereof is set as a threshold value (page 19, upper right column, line 19 to lower left column, line 5 of the same publication).

Further, as another conventional technique, there is known an abnormality detection apparatus for a drilling tool disclosed in Japanese Patent Application Laid-Open No. 61-252053. In this apparatus, a means for detecting a load applied to a drilling tool, a data storage means for receiving a load signal from the load detecting means and storing representative load data for each drilling process among the load signals, Computing means for calculating the standard deviation from the representative load data at the latest machining frequency, and comparing the standard deviation obtained by the computing means with the reference standard deviation, and when the standard deviation is larger than the reference standard deviation, an abnormality determination signal Is output. In this case, the reference standard deviation is set by multiplying the calculated standard deviation by a coefficient k obtained by an experiment as a correction coefficient for compensating for the individual difference between drills. Is calculated every time the drill is replaced (17th line in the upper left column on page 3 of the official gazette or the 2nd line in the upper right column of the same page).

[0009]

SUMMARY OF THE INVENTION Among the above prior arts, Japanese Patent Application Laid-Open No. 61-192449 and Japanese Patent Application Laid-Open No. 2-95
In the technique disclosed in Japanese Patent Application Publication No. 54-54, the set threshold value (set value) is not corrected according to the situation of the change in the load applied to the rotating tool during machining. Therefore, it is not possible to cope with a variation in load applied to the device or a sudden change, and it has been desired to improve the accuracy of abnormality detection.

Further, in the technique disclosed in Japanese Unexamined Patent Publication No. Hei 4-201159, a value obtained by multiplying or adding a predetermined value to an average value of signal values immediately before the first spike-like signal is generated is used as a threshold value. Therefore, the threshold value is not set by directly considering the damage level of the rotating tool. In addition, in order to calculate the threshold value based on the average value of the signal values, as described above, the load applied to the rotary tool suddenly increases due to the disturbance factor while the data for calculating the average value is acquired. In such a case, there is a problem that the abnormality detection is delayed and cannot be properly dealt with.

Further, in the apparatus disclosed in Japanese Patent Application Laid-Open No. 61-252053, the threshold value (reference standard deviation) is set by correcting the standard deviation with a correction coefficient k for compensating for individual differences between drills. In addition, since the calculation of the standard deviation is performed every time the drill is replaced, there has been a problem that it is not possible to detect an abnormality of the rotating tool during machining in real time.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems in an advantageous manner, and has a simple configuration, and a method and apparatus for detecting a rotary tool capable of accurately detecting an abnormality of the rotary tool in real time and appropriately. The purpose is to provide.

[0013]

The invention according to claim 1 is
In order to achieve the above object, a method of detecting a load applied to a rotating tool during machining, and detecting an abnormality of the rotating tool based on the load and a set threshold value, in a normal state of the rotating tool It is characterized in that a threshold value of the load and a threshold value of the load in the abnormal state are set, and the abnormality of the rotary tool is determined by comparing the detected load with one of the two threshold values. Is what you do.

According to a second aspect of the present invention, in order to achieve the above object, in the first aspect of the invention, the load applied to the rotary tool is a load threshold value and / or an abnormal value in a normal state of the rotary tool. The number of times using the load threshold value in the state is counted.

According to a third aspect of the present invention, there is provided a method for detecting a load applied to a rotary tool during machining and detecting an abnormality of the rotary tool based on the load and a threshold value. , Set the damage load level according to the rotating tool, find the rate of change from the detected load, set a threshold based on the damage load level and the rate of change of the load,
The abnormality of the rotary tool is determined by comparing the set threshold value with the detected load.

According to a fourth aspect of the present invention, there is provided a load detecting means for detecting a load applied to a rotary tool during machining, a threshold value being stored, and a load detected by the load detecting means. A rotating tool abnormality detecting device comprising: a calculating means for detecting an abnormality of the rotating tool based on the threshold value; wherein the calculating means includes a load threshold value in a normal state of the rotating tool and a load threshold value in an abnormal state of the rotating tool. The threshold value is stored, and an abnormality of the rotary tool is determined by comparing one of the two threshold values with the load and performing an arithmetic operation.

According to a fifth aspect of the present invention, in order to achieve the above object, in the invention of the fourth aspect, the load applied to the rotary tool is a load threshold value and / or an abnormal value in a normal state of the rotary tool. It has a counting means for counting the number of times using the threshold value of the load in the state.

According to a sixth aspect of the present invention, in order to achieve the above object, a load detecting means for detecting a load applied to a rotary tool during machining, and a load and a threshold value detected by the load detecting means. A rotating tool abnormality detecting device comprising: a rotating tool abnormality detecting device, wherein the calculating means stores a damage load level set according to the rotating tool, and calculates a change rate of the detected load. Then, a threshold value is set from the damage load level and the rate of change of the load, and the threshold value is compared with the load to determine whether the rotary tool is abnormal.

According to the first aspect of the present invention, the threshold value of the load in the normal state of the rotary tool and the threshold value of the load in the abnormal state are set. The load threshold in the abnormal state is set lower than the load threshold in the normal state. Detect the load of the rotating tool during machining, find the rate of change and the standard deviation of the rate of change, and if the rate of change is within a predetermined standard deviation, select the load threshold in the normal state, If the rate is not within the predetermined standard deviation, a threshold value of the load in the abnormal state is selected, and the detected load is compared with one of the selected thresholds. If it exceeds, it is determined to be abnormal.

In the invention according to claim 2, the number of times that the load applied to the rotary tool uses the load threshold value in a normal state of the rotary tool and / or the load threshold value in an abnormal state of the rotary tool is counted. In particular, by counting the number of times using the threshold value of the load in the abnormal state, the machining state of the rotary tool is determined, for example, a load has been applied to the rotary tool due to a disturbance factor and an abnormality has occurred.

According to the third aspect of the present invention, a damage load level corresponding to the rotary tool is set, a load applied to the rotary tool during machining is detected, and a change rate thereof is obtained. The threshold value is determined by multiplying the set damage load level by a constant determined from the obtained load change rate. The threshold decreases when the rate of change of the determined load is large,
The load fluctuates according to the change rate so as to increase when the change rate is small. The threshold value is compared with the detected load, and if the load exceeds the threshold value, it is determined that the load is abnormal.

According to the fourth aspect of the present invention, the load applied to the rotating tool being machined is detected by the load detecting means, and the detected load is sent to the calculating means. The calculation means stores a load threshold value in a normal state of the rotary tool and a load threshold value in an abnormal state of the rotary tool. The load threshold in the abnormal state is set lower than the load threshold in the normal state. The calculating means calculates a change rate of the detected load and a standard deviation of the change rate, and when the change rate is within a predetermined standard deviation, selects a threshold value of the load in the normal state, and sets the change rate to a predetermined value. If not within the standard deviation of, select the load threshold in the abnormal state, compare the detected load with one of the selected threshold,
If the load exceeds the selected threshold, it is determined that the load is abnormal.

In the invention according to claim 5, the number of times the load applied to the rotary tool is counted by the counting means using a load threshold value in a normal state of the rotary tool and / or a load threshold value in an abnormal state. . In particular, by counting the number of times using the threshold value of the load in the abnormal state, the machining state of the rotary tool is determined, for example, a load has been applied to the rotary tool due to a disturbance factor and an abnormality has occurred.

In the invention according to claim 6, a damage load level corresponding to the rotary tool is set and stored in the calculating means. The load applied to the rotary tool during machining is detected by the load detecting means, and the rate of change is determined. The calculating means determines a threshold value by multiplying the set damage load level by a constant determined from the obtained load change rate. The threshold value varies according to the change rate such that the threshold value decreases when the calculated change rate of the load is large, and increases when the calculated change rate of the load is small. The calculation means compares the threshold value with the detected load, and determines that the load is abnormal when the load exceeds the threshold value.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method and an apparatus for detecting an abnormality of a rotary tool according to the present invention will be described in detail with reference to FIGS. In this embodiment, a description will be given of the case of a drill attached to the spindle motor M of the processing apparatus D as the rotary tool T. However, the present invention is not limited to this and can be applied to other rotary tools. It is of course applicable.

As shown in FIG. 1, an apparatus 1 for detecting an abnormality of a rotary tool according to the present invention generally comprises a spindle motor M of a machining apparatus D.
A load detecting means 10 for detecting the driving current of the spindle T, and a threshold value stored therein, and a calculation for detecting an abnormality of the drill T by comparing the load current of the spindle motor M detected by the load detecting means 10 with the threshold value. Means 11.

The drill T is a chuck (not shown).
And the like, is held by a spindle motor M of the processing apparatus D, and is rotated around the axis. The work W is arranged on the bed B of the processing device D so as to face the drill T. The load detecting means 10 detects a load value for each work of the drill T by detecting a drive current of the spindle motor M,
The load value is output to the calculating means 11. The load detecting means 10 can select an optimal means for electrically or mechanically detecting the load, such as a torque sensor or a thrust sensor, according to the rotary tool T, in addition to the means for detecting the load current.

In the arithmetic means 11, a load threshold L _high in a normal state of the drill T and a load threshold L _low in an abnormal state are set and stored in advance. FIG.
As shown in the threshold L _low load in abnormal conditions
Is set lower than the load threshold L _high in the normal state.

FIG. 4 shows one drill T performed by the calculating means 11.
2 shows an algorithm for judging the abnormality of the above. Computing means 11 takes the load value signal X _n of the respective processing each output from the load detecting means 10 (S1), a load value of the change rate _{ΔX n (= (X n -X} n-1) / sampling time) and calculating the standard deviation Sigma] [Delta] _Xn of the change rate ΔX _n (S2). In addition, the sampling time may be set by dividing the time required for each processing into a predetermined time,
The time required for each process can be set as one unit. When the sampling time is set by dividing the time required for each processing into a predetermined time, the load value detected first for each processing is defined as the load value detected for each processing, and the time required for each processing is defined as one unit. When the sampling time is set, the load values detected in the first processing are 0
Because the rate of change increases because it increases from
These detected initial load values are compared with a load threshold L _high in the normal state of the drill T.

As shown in FIG. 3, the rate of change ΔX of the load value is
And a left-right symmetric curve with the average value ΔX bar
Assuming a substantially normal distribution, the normal processing shown in FIG.
Load value X in state_na, X_nbRate of change ΔX_na, ΔX_nb
Is the average ΔX bar ± 3σΔ of ΔX shown in FIG._X (Post
(Semi-deviation). Therefore, the rate of change ΔX _na
Or ΔX_nb<ΔX bar ± 3σΔ_X (S3
In the case of YES), it is determined that the workpiece is in the normal machining state,
Load threshold L in the state_highIs selected (S4).
Then, the selected threshold L_highAnd load value X_na, X_nb
(S5), and the load value X_na, X_nbIs the threshold L
_highLess than (X_na, X_nb<L_{hi gh}Is YES
Case), it is assumed that there is no abnormality in the drill T
The determination algorithm of that time is ended. Also, the load value X
_na, X_nbIs the threshold L_highIs exceeded (X_na, X_nb<
L_highIs NO), the drill T is abnormal at that point
To stop the processing device D
Step or alarm means to indicate the occurrence of an abnormality (not shown)
(Abbreviated), an abnormality detection signal is output (S8).

On the other hand, abnormalities are caused by disturbance factors shown in FIG.
Occurs and the load value X_ncRate of change ΔX _ncRose sharply
In this case, the average value Δ of the load value change rate ΔX shown in FIG.
X bar ± 3σΔ_X Is not included in the range. did
Therefore, the rate of change ΔX_nc> ΔX bar ± 3σΔ_X If
In the case of (NO in S3), it is determined that an abnormal state has occurred.
And the load threshold L in the abnormal state_low Select
(S6), this threshold L_low And load value X_ncAnd compare
(S7), load value X_ncIs the threshold L_low Place smaller than
(X_nc<L_low If YES), drill T is abnormal
Algorithm that has not occurred
To end. Also, the load value X_ncIs the threshold L_low Beyond
(X_nc<L_low If NO), fold the drill T
Loss prediction, that is, when it is determined that an abnormality has occurred,
It is output (S8).

As described above, in this embodiment, the load threshold value L in the normal state of the rotary tool is set.
A simple configuration that sets the _high and the load threshold L _low in the abnormal state, selects one of the thresholds according to the rate of change of the load, and compares it with the load value. Can be appropriately detected.

Further, although the rotary tool abnormality detecting device 1 according to the present invention in this embodiment is not shown,
Either the load threshold L _high in the normal state of the drill T or the load threshold L _low in the abnormal state is selected (S4 or S6 in FIG. 4), and the selected threshold is used. There is provided a counting means for counting whether the load value ( _Xna , _Xnb or _Xnc ) has been compared (S5 or S7). When the load value changes so as to increase rapidly, and the load value is often compared with the threshold value L _low , the setting of the processing apparatus D such as holding of the drill T, feeding to the work W, rotation speed, and the like. It is determined that a disturbance factor occurs due to the improperness of the processing device D, and a countermeasure for occurrence of an abnormality is performed on the processing apparatus D.

Next, a second embodiment of a method and an apparatus for detecting abnormality of a rotary tool according to the present invention will be described with reference to FIGS.
It will be described in detail based on. In this embodiment, the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The calculating means of the apparatus for detecting abnormality of a rotary tool according to this embodiment generally includes a drill T as a rotary tool.
Is stored, a change rate of the load applied to the drill T detected by the load detecting means 10 is obtained, and a threshold is set from the damage load level and the change rate of the load. The abnormality of the rotary tool is detected by comparing the threshold value and the load.

As shown in FIG. 6, the damage load level _Lmax stored in the calculating means is set to be constant according to the size of the drill T and the like. FIG. 5 shows an algorithm for judging abnormality of one drill T performed by the calculating means 11 in this embodiment. The calculating means 11 is a load detecting means 1
The load value signal X _n for each machining output from 0 is fetched (S10), and the load value change rate ΔX _n (= (X _n −X
_n-1 ) / sampling time) is calculated (S11).
Next, the calculating means 11 calculates the change rate ΔX _n of the load value from
A constant k in the range of 0 to 1 is determined (S12). This constant k, as shown in FIG. 7, as the change rate [Delta] X _n load value is large that number smaller and its numerical change rate [Delta] X _n load value is smaller is previously set to be larger.

Subsequently, the determined constant k is changed to the damage load.
Level L_max To the damage load level L
_max Set a threshold that is a predetermined percentage level for
Is performed (S13). Therefore, as shown in FIG.
Load value X in normal processing state_ndRate of change ΔX_ndIs a comparison
The threshold is the damage load level L_max Near
Is set to, and conversely,
Load value X_neRate of change ΔX _neIf rises sharply, then
The threshold value is the load value X in the normal machining state._ndSet by
Is set lower than the threshold value.

Thereafter, the set threshold value is compared with the detected load value (S14). If the load value _Xn is smaller than the threshold value ( _Xn <L is YES), the drill is performed. Assuming that no abnormality has occurred, the determination algorithm for that time is ended. When the load value _Xn exceeds the threshold value L (when _Xn <L is NO), it is determined that an abnormality has occurred in the drill, and an abnormality signal is output (S15).

As described above, in this embodiment, the simple configuration of setting the threshold value according to the rate of change of the load value allows the abnormality of the rotary tool to be detected accurately and appropriately in real time. Can be.

[0040]

According to the first aspect of the present invention, the threshold value of the load in the normal state of the rotary tool and the threshold value of the load in the abnormal state are set, and the detected load and the two threshold values are set. Therefore, the configuration of the method for detecting the abnormality of the rotary tool can be simplified, and the abnormality can be accurately and appropriately detected.

According to the second aspect of the present invention, in the first aspect, the load applied to the rotary tool is a load threshold value in a normal state of the rotary tool and / or a load threshold value in an abnormal state. Therefore, it is possible to appropriately determine the occurrence of an abnormality in the processing apparatus using the rotary tool, and to take measures against disturbance factors that cause the abnormality.

According to the third aspect of the present invention, a damage load level corresponding to the rotating tool is set, the rate of change is determined from the detected load, and a threshold value is determined based on the damage load level and the change rate of the load. Is set, and the set threshold value is compared with the detected load, so that the configuration of the abnormality detection method for the rotary tool can be simplified, and the abnormality detection is accurately performed in real time. be able to.

According to the fourth aspect of the present invention, the load threshold value in the normal state of the rotary tool and the load threshold value in the abnormal state are stored in the arithmetic means, and either one of the two threshold values is stored. With the configuration for comparing the load with the load, the configuration of the abnormality detection device for the rotary tool can be simplified, and the abnormality can be detected easily, accurately, and appropriately.

According to the invention of claim 5, in the invention of claim 4, the load applied to the rotary tool is a load threshold value in a normal state of the rotary tool and / or a load threshold value in an abnormal state. By having the counting means for counting the number of times of comparison, it is possible to appropriately determine the occurrence of an abnormality in the processing apparatus using the rotary tool, and to easily take measures against disturbance factors that cause the abnormality.

According to the invention of claim 6, the damage load level set according to the rotating tool is stored in the calculating means,
Since the load change rate detected by the calculating means is determined, a threshold value is set from the damage load level and the load change rate, and the threshold value is compared with the load to calculate, the rotary tool abnormality detection device Can be simplified, and abnormality detection can be accurately performed in real time.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an abnormality detection device for a rotary tool according to the present invention.

FIG. 2 shows a change in a load value applied to the rotary tool according to the first embodiment of the present invention, and a set load threshold in a normal state and a set load threshold in an abnormal state of the rotary tool. It is a graph.

FIG. 3 is a graph showing a standard deviation of a load.

FIG. 4 is a flowchart illustrating an algorithm for determining an abnormality of one drill performed by a calculation unit according to the first embodiment of the present invention.

FIG. 5 is a flowchart illustrating an algorithm for determining an abnormality of one drill performed by a calculation unit according to the second embodiment of the present invention.

FIG. 6 is a graph showing a change in a load value applied to a rotary tool, a change in a set threshold value of the load of the rotary tool, and a damage level according to the set rotary tool in the second embodiment of the present invention. It is.

FIG. 7 is a graph showing a change with respect to a load change rate of a constant k multiplied by a damage level according to a set rotary tool in the second embodiment of the present invention.

FIG. 8 is a graph for explaining a difference in change of damage caused by friction of a rotating tool and a disturbance factor.

[Description of sign]

1 abnormality detecting device 10 load detecting means 11 calculating means T drilling (rotary tool) L _high load in threshold L _LOW abnormal state of the load in the normal state of the rotation tool threshold X _n load value [Delta] X _n load of the rotary tool Value change rate σΔ _X standard deviation L _max damage load level k constant

Claims (6)

[Claims] 1. A method for detecting a load applied to a rotary tool during machining, and detecting an abnormality of the rotary tool based on the load and a set threshold value. Setting a threshold value and a threshold value of a load in an abnormal state, and comparing the detected load with one of the two threshold values to determine abnormality of the rotary tool; Tool error detection method. 2. The method according to claim 1, wherein the number of times the load applied to the rotary tool is counted using a load threshold value in a normal state of the rotary tool and / or a load threshold value in an abnormal state. 3. The method for detecting an abnormality of a rotary tool according to 1. 3. A method for detecting a load applied to a rotary tool during machining, and detecting an abnormality of the rotary tool based on the load and a threshold value, wherein a damage load level according to the rotary tool is set. The change rate is determined from the detected load, a threshold value is set based on the damage load level and the change rate of the load, and the set threshold value is compared with the detected load to obtain the rotation tool. An abnormality detection method for a rotary tool, characterized by determining an abnormality. 4. A load detecting means for detecting a load applied to the rotating tool during machining, and a threshold value are stored, and an abnormality of the rotating tool is detected based on the load and the threshold value detected by the load detecting means. A rotating tool abnormality detecting device comprising: a calculating means, wherein the calculating means stores a load threshold value in a normal state of the rotating tool and a load threshold value in an abnormal state of the rotating tool; An abnormality detection device for a rotary tool, wherein an abnormality of the rotary tool is determined by comparing and calculating one of the loads and a load. 5. A counter for counting the number of times the load applied to the rotary tool uses a load threshold value in a normal state of the rotary tool and / or a load threshold value in an abnormal state of the rotary tool. The rotating tool abnormality detection device according to claim 4. 6. A load detecting means for detecting a load applied to a rotary tool during machining, and a calculating means for detecting an abnormality of the rotary tool based on the load detected by the load detecting means and a threshold value. An abnormality detection device for a rotary tool, wherein the calculating means stores a damage load level set according to the rotary tool, obtains a change rate of the detected load, and calculates a threshold from the damage load level and the load change rate. An abnormality detection device for a rotary tool, wherein a value is set, and a threshold value and a load are compared to calculate an abnormality of the rotary tool.