JP2006315158A - Mounting state abnormality determination method for machine tool and tool holder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mounting state abnormality determination method for a machine tool and a tool holder, simply and surely detecting a chuck error in a machine tool where a tool holder to which a tool is fitted is mounted on a spindle, and the spindle is driven in rotation to machine a work. <P>SOLUTION: The machine tool includes: distance measuring means 12, 31 for measuring the distance from a predetermined measurement point to the outer peripheral surface of a flange of a tool holder mounted on the spindle; a rotation amount detecting means 32 for detecting the rotation amount of the flange; a maximum value select means 34 for selecting the maximum value at intervals of a predetermined amount of measurement data obtained by the distance measuring means based upon the rotation amount detected by the rotation amount detecting means 32; and a mounting state determination means 35 for determining the abnormality of mounting state of the tool holder to the spindle on the basis of a change with the passage of time of the maximum value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a machine tool, and more particularly to a machine tool that automatically detects a tool chuck error in a machining center (MC).

  The MC is an apparatus that automatically selects various tools according to a machining process and automatically attaches them to a spindle to perform various types of machining. In this MC, tool change is performed by an automatic tool change (ATC: auto tool holder change) device, and the ATC device automatically takes out the tool holder to which the tool is attached from the tool magazine and automatically attaches it to the spindle.

  As shown in FIG. 17A, the tool holder 2 that holds the tool 1 has a conical fitting portion 2A, and this fitting portion 2A is formed in a conical shape formed on the main shaft 3. It is fitted to the fitting portion 3A. However, as shown in FIG. 17B, when chips 94 or the like adhere to the fitting portion, the rotating shaft is bent and attached. When the main shaft is rotated at a high speed in this state, there is a risk that the tool holder 2 that holds the tool 1 falls off the main shaft 3 due to the circular force caused by the deflection of the tool 1.

  Conventionally, such a chuck error of the tool holder is detected by, for example, irradiating the tool tip of the tool holder mounted on the spindle with a laser beam and detecting whether or not the tool tip exists at a predetermined position. It was. That is, if there is no chuck mistake in the tool holder, the tip of the tool should always be in a predetermined position, and it is determined that there is a chuck mistake if the tip of the tool is not in a predetermined position.

  In addition, the applicants of the present application measure the displacement of the outer peripheral surface of the flange 2B of the tool holder 2 with an eddy current sensor or the like to detect a change in the displacement accompanying the rotation of the tool holder 2, and thereby the chuck error of the tool holder 2 (For example, Patent Document 1 and Patent Document 2 below).

Japanese Patent Laid-Open No. 2002-200542 JP 2003-334742 A

However, the conventional method of detecting the presence / absence of the tip of a tool with a laser beam has a drawback in that under a situation where a large amount of coolant is used as in MC, the laser beam is easily blocked by the coolant and detection errors are likely to occur. is there.
Moreover, the notch for a chuck | zipper is normally provided in the flange 2B outer peripheral surface of the tool holder 2 so that it may mention later. Therefore, in the conventional method for measuring the change in the position of the outer peripheral surface of the flange 2B, the measurement value fluctuates due to unevenness such as this notch, and therefore it is difficult to determine the chuck error of the tool holder 2 with a simple configuration. It was.

  In view of the above problems, an object of the present invention is to provide a machine tool and a tool holder mounting state abnormality determination method that can easily and reliably detect a chuck error.

It is known that when the tool holder falls off the main shaft, the amount of displacement of the tool holder attached to the main shaft gradually increases as the main shaft rotates at a higher speed, and the tool deflection increases accordingly. Therefore, in the present invention, the abnormality of the mounting state of the tool holder on the spindle is determined based on the change over time of the displacement amount of the outer peripheral surface of the flange of the tool holder.
At that time, a maximum value of the displacement amount measured when the flange rotates over a predetermined rotation amount is obtained, and an abnormality in the mounting state of the tool holder on the spindle is determined based on a change with time of the maximum value. .

  That is, in the machine tool according to the first embodiment of the present invention, in a machine tool in which a tool holder to which a tool is attached is mounted on a main shaft and the main shaft is rotationally driven to process a workpiece, from a predetermined measurement point to the main shaft. Based on the distance measurement means for measuring the distance to the outer peripheral surface of the flange of the mounted tool holder, the rotation amount detection means for detecting the rotation amount of the flange, and the rotation amount detected by the rotation amount detection means, the distance measurement means A maximum value selecting means for selecting a maximum value for each predetermined rotation amount of the measured data, and a mounting state determining means for determining an abnormality in the mounting state of the tool holder on the spindle based on a change with time of the maximum value. It is prepared for.

  In addition, according to the second embodiment of the present invention, a method for determining an abnormal state of attachment of a tool holder in a machine tool having a main shaft includes a tool holder mounted on the main shaft, and the machine tool that rotationally drives the main shaft from a predetermined measurement point. , Measure the distance to the outer peripheral surface of the flange of the tool holder attached to the spindle, detect the rotation amount of the flange, select the maximum value for each predetermined rotation amount of the measurement data measured based on the detected rotation amount, An abnormality in the mounting state of the tool holder on the spindle is determined based on the change over time of the selected maximum value.

  Here, the rotation amount detection means detects the rotation amount of the flange by detecting a position mark provided on the outer peripheral surface of the flange. This position mark may be installed by a notch or the like provided on the outer peripheral surface of the flange. At this time, the rotation amount detecting means detects the notch based on the measurement data of the distance measuring means. Good.

  When the maximum value measured at a certain point of time is greater than the maximum value measured before that by a predetermined threshold or more, the mounting state determination means indicates that the mounting state of the tool holder on the spindle is abnormal. Judge that there is. At this time, the maximum value selecting means may select the maximum value of the measurement data measured while the tool flange is rotated one or more times.

  In addition, the mounting state determination means calculates a cumulative value of differences between the maximum values measured at different times, and when this cumulative value exceeds a predetermined threshold, the mounting state of the tool holder on the spindle is abnormal. It may be determined that At this time, the wearing state determination means may calculate a cumulative value of differences between the maximum values measured at different times for the same portion of the outer peripheral surface of the flange.

  Further, the mounting state determination means calculates a cumulative value for each of a plurality of different portions of the outer peripheral surface of the flange, and when the sum of these cumulative values exceeds a predetermined threshold, the mounting state of the tool holder on the spindle May be determined to be abnormal.

  The maximum value of the displacement of the outer peripheral surface of the flange is obtained for each predetermined amount of rotation of the flange, and the abnormal value of the mounting state is determined based on the change over time. Since the behavior of the rotating tool holder can be captured regardless of fluctuations, it is possible to easily and reliably determine the abnormal state of the tool holder.

  Hereinafter, preferred embodiments of a machine tool according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing a first embodiment of a chuck error detection device incorporated in a machine tool according to the present invention. The chuck error detection device 10 is a device that automatically detects a chuck error of the tool holder 2 mounted on the spindle 3 by an ATC device, and mainly includes a distance measuring sensor 12 and a data processing device 14.

  The distance measuring sensor 12 is attached via a bracket 6 to a head 5 to which the main shaft 3 is attached. The distance measuring sensor 12 detects a distance d to the outer peripheral surface of the flange portion 2B of the tool holder 2 attached to the main shaft 3 as an electric signal. Although an eddy current sensor can be used as the distance measuring sensor 12, any other distance measuring sensor capable of measuring the distance from a specific measurement point to the outer peripheral surface of the tool holder 2 can be used as an eddy current sensor. Not limited to this, other sensors may be used. In this case, not only a non-contact type sensor such as an eddy current sensor but also a contact type sensor may be used.

The data processing device 14 detects a chuck error of the tool holder 2 based on the measurement data measured by the distance measuring sensor 12, and includes an A / D converter 16, a CPU 18, a memory 20, an input / output circuit 22, and the like. .
The A / D converter 16 converts the electrical signal indicating the distance d output from the distance measuring sensor 12 into a digital signal and outputs the digital signal to the CPU 18. As will be described later, the CPU 18 determines an abnormality in the mounting state of the tool holder 2 on the spindle 3 based on the change over time of the measurement data of the sensor 12 converted into the digital signal, and inputs and outputs the determination result. The signal is output to the MC controller 24 that controls the MC via the circuit 22.

  FIG. 2A is a functional block diagram realized by the data processing device 14 shown in FIG. As shown in the figure, the data processing device 14 outputs the distance measurement unit 31 that measures the distance d to the outer peripheral surface of the flange portion 2B based on the distance signal output from the distance measurement sensor 12 and the distance measurement unit 31. A rotation amount detection unit 32 that detects the rotation amount of the flange 2B based on the measurement data, and the predetermined rotation amount of the measurement data obtained by the distance measurement unit 31 based on the rotation amount detected by the rotation amount detection unit 32 Each function block is realized by a maximum value selection unit 34 that selects a maximum value for each and a mounting state determination unit 35 that determines an abnormality in the mounting state of the tool holder 2 based on a change with time of the maximum value. .

  Further, the rotation amount detection unit 32 includes a notch detection unit 36 that detects a notch provided on the outer peripheral surface of the flange portion 2B of the tool holder 2 described later. Furthermore, the data processing device 14 includes a functional block that forms a rotation detection unit 33 that detects the start and end of rotation of the flange 2B based on the notch detection frequency of the notch detection unit 36 according to the rotation speed of the flange 2B. Realize.

Hereinafter, the operation of the rotation amount detection unit 32 will be described with reference to FIGS. FIG. 3 is a plan view of the tool holder 2 having a notch in the flange portion 2B.
As shown in FIG. 3, a notch portion 2 </ b> C for the chuck is formed on the outer peripheral surface of the flange portion 2 </ b> B of the tool holder 2. The measurement data when the notch portion 2C is at the measurement position of the distance measuring sensor 12 is greatly different from the measurement data when the other flange portion outer peripheral surface 2D is at the measurement position. Accordingly, measurement data obtained when the outer peripheral surface portion 2D (measurement section) other than the notch is at the measurement position of the distance measuring sensor 12 is used to determine whether the tool holder 2 is mounted or not.
On the other hand, since the position of the notch portion 2C formed on the outer periphery of the flange and the interval between the notches are known, the rotation amount of the flange 2B is detected by detecting the notch portion 2C from the measurement data of the distance measuring sensor 12. Is possible.

  Therefore, the rotation amount detection unit 32 identifies the notch portions 2C and 2C based on the measurement data of the distance measuring sensor 12 by the notch detection unit 36. Then, the rotation amount of the flange 2B is detected in accordance with the number of notches 2C detected by the notch detector 36. 4 is an operation flowchart of the rotation amount detection unit 32 shown in FIG. 2A, and FIG. 5 is an operation explanatory diagram of the rotation amount detection unit 32 shown in FIG.

  First, at time t0 to t1, the notch detection unit 36 inputs the output of the distance measuring sensor 12 that performs measurement at predetermined time intervals, and stores the measurement value Vs at that time as the maximum value Vmax of measurement data (step S11). ). At this time, the notch detection unit 36 stores the measurement data other than the notch portion as the maximum value Vmax. When the tool holder 2 rotates at a low speed immediately after the rotation starts, measurement data larger than a predetermined value is input. When there is, the measured value Vs may be obtained.

From time t1 to t2, the notch detection unit 36 inputs the output of the distance measuring sensor 12 that performs measurement every predetermined time and measures the current value Vc of the measurement data (step S12). In FIG. 5, the horizontal axis indicates the passage of time, and the vertical axis indicates the measurement data of the distance measuring sensor 12 at each time.
In step S13, the notch detection unit 36 determines whether or not the difference between the stored Vmax and the current value Vc is greater than a predetermined notch discovery determination value (Vmax−Vc> notch discovery measurement value). When Vmax−Vc> notch discovery measurement value holds (time t2), the notch detection unit 36 proceeds to step S14 assuming that the first notch is found, and repeats steps S12 to S13 when not found.

At time t2, the notch detection unit 36 stores the average value ((Vmax + Vc) / 2) of the stored Vmax and the current value Vc as a notch determination value (Th1 shown in FIG. 5) (step S14). At this time, in step S15, the current operation mode of the rotation amount detection unit 32 is stored as the notch mode.
Thereafter, at times t2 to t3, the notch detection unit 36 acquires the minimum value Vmin1 of the measurement data of the distance measuring sensor 12 in step S16.

  After acquiring the minimum value Vmin, the notch detection unit 36 acquires the current value Vc of the measurement data of the distance measuring sensor 12 in step S17, and in step S18, the notch detection unit 36 determines that the current value Vc is the notch determination value. It is determined whether or not it has become larger than Th1 (Vc> Th1). When Vc> Th1 is satisfied (time t3), the notch detection unit 36 moves the process to step S19, and when not satisfied, repeats steps S17 to S18.

  At time t3, the notch detection unit 36 calculates an average value ((Vmax + Vmin1) / 2) of the maximum value Vmax (= Vs) measured and stored immediately before and the minimum value Vmim1 measured and stored immediately before (notch determination value ( This is stored as Th2) shown in FIG. 5 (step S19). In step S20, it is determined whether or not the current value Vc of the measurement data is larger than the next notch determination value Th2 (Vc> Th2). If larger, the process proceeds to step S22. Until the current value Vc of the measurement data becomes larger than the next notch determination value Th2, the current value Vc of the measurement data (step S21) and the above determination (step S20) are repeated.

If it is determined that the current value Vc of the measurement data is greater than the current notch determination value Th1 (step S18) and greater than the next notch determination value Th2 (step S20), at time t3, step S22 is performed. Thus, the current operation mode of the rotation amount detection unit 32 is stored as the normal mode (corresponding to the measurement section).
In step S23, the notch determination value is updated to the next notch determination value calculated in step S19. The maximum value Vmax and the minimum value Vmim1 stored at this time are also cleared.

Thereafter, at times t3 to t4, the notch detection unit 36 acquires the maximum value Vmax1 of the measurement data of the distance measuring sensor 12 in step S24.
After acquiring the maximum value Vmin1, the notch detection unit 36 acquires the current value Vc of the measurement data of the distance measuring sensor 12 in step S25, and in step S26, the notch detection unit 36 determines that the current value Vc is the notch determination value. It is determined whether it has become smaller than Th2 (Vc <Th2). When Vc <Th2 is satisfied (time t4), the notch detection unit 36 returns the process to step S15, and when not satisfied, repeats steps S25 to S26.

  Thereafter, the notch detection unit 36 changes the operation mode of the rotation amount detection unit 32 to the notch mode in the same manner as the processing performed for the notch part at time t2 to time t3 (step S15), and measures the minimum value Vmin2. The measured value is monitored until the current value becomes larger than the notch determination value Th2 at time t5 (S17, S18), the next notch determination value Th3 is calculated (S19), and the current value is determined at time t6. The measured value is monitored until it becomes larger than the next notch determination value Th3 (S20, S21), and then the operation mode of the rotation amount detection unit 32 is changed to the normal mode at time t6 (step S22), and the switching determination value is updated. (S23).

  Thereafter, by repeating such steps S15 to S26, the notch detection unit 36, based on the measurement data of the distance measuring sensor 12, the maximum value (peak value) and minimum of the measurement data detected immediately before. The boundary between the notch and the other measurement section is detected using the average value as a threshold value. Thereby, the notch detection part 36 can always identify a notch part irrespective of the outer diameter of the tool holder 2. FIG.

The operation mode of the rotation amount detection unit 32 updated by the notch detection unit 36 is an alternating signal that alternates the number of times proportional to the rotation amount of the flange portion 2B. Therefore, the rotation amount detection unit 32 outputs a signal indicating this operation mode to the maximum value selection unit 34 (FIG. 2) as a signal indicating the rotation amount of the flange portion 2B.
This operation mode is an alternating signal that alternates at a frequency proportional to the rotational speed of the flange portion 2B. Therefore, the rotation amount detection unit 32 outputs a signal indicating this operation mode to the rotation detection unit 33 (FIG. 2) that detects the rotation start and rotation end of the flange portion 2B.

  Hereinafter, with reference to FIG. 6 to FIG. 7, the rotation start / stop determination operation of the flange 2 by the rotation detection unit 33 illustrated in FIG. 2A will be described. FIG. 6 is an operation flowchart of the rotation detection unit 33, and FIG. 7 is an operation explanatory diagram of the rotation detection unit 33.

  The rotation detection unit 33 measures the time from the end of the notch mode detected by the rotation amount detection unit 32 to the end of the next notch mode, and this time is equal to or less than a predetermined rotation determination interval period Trot (constant). In such a case, the rotation start is detected when the predetermined rotation start determination interval number of times Bstart (constant) continues.

Therefore, the rotation detection unit 33 first initializes the rotation start determination section counter Cstart (variable) in step S31, and in step S32, from the end of the notch mode detected by the rotation amount detection unit 32 to the end of the next notch mode. Time T is measured.
In step S33, it is determined whether or not the measured time T is equal to or shorter than the in-rotation determination period cycle Trot (T ≦ Trot). When T> Trot, the rotation start determination section counter Cstart is cleared in step S34, and the process returns to step S32.

  On the other hand, if it is determined in step S33 that T ≦ Trot, the rotation detection unit 33 counts up the rotation start determination section counter Cstart in step S35. The above steps S32 to S35 are repeated until the rotation start determination section counter Cstart becomes equal to the rotation start determination section number Bstart (step S36). When the rotation start determination section counter Cstart becomes equal to the rotation start determination section count Bstart, the rotation detection unit 33 determines that the flange 2 has started rotating in step S37.

For example, in the example shown in FIG. 7, the times T1 to T5 from the end of the notch mode to the end of the next notch mode are T1 ≦ Trot, T2> Trot, T3 ≦ Trot, T4 ≦ Trot, T5 ≦ Trot, respectively. Yes, it is assumed that the rotation start determination section number Bstart = 3.
Then, since time T1 is less than or equal to Trot, Cstart counts up to “1”, and after that time T2 is greater than Trot, Cstart is cleared to “0”, and since time T3 is less than or equal to Trot, Cstart is counted. Since the time T4 is less than Trot, Cstart is counted up to “2”, and since time T5 is less than Trot, Cstart is counted up to “3”. Here, since Cstart becomes equal to Bstart, the rotation detection unit 33 determines that the flange 2 has started rotating at the end of time T5.

  Returning to FIG. 6, thereafter, the rotation detection unit 33 continues to measure the time T from the end of the notch mode detected by the rotation amount detection unit 32 to the end of the next notch mode (step S38). Is larger than the in-rotation determination section period Trot (step S39), it is determined in step S40 that the flange 2 has stopped rotating.

Hereinafter, each example of the mounting state determination unit 35 shown in FIGS. 2A and 2A will be described, and the mounting state abnormality determination method for the tool holder 2 according to the present invention will be described.
The maximum value selection unit 34 in FIG. 2A continues while the notch detection unit 36 detects the notch 2C shown in FIG. 3 a predetermined number of times, that is, while the flange 2B rotates by a predetermined amount of rotation. Among the measurement data measured by the distance measuring sensor 12, the maximum measurement data is calculated.
As shown in FIG. 8, the measurement data of the distance measuring sensor 12 includes valley portions t1 to t2 and t3 to t4 (rotation amount detection unit 32) when measuring the displacement of the section of the notch 2C (see FIG. 3). Is a portion operating in the notch mode), and mountain portions t2 to t3 when measuring the displacement of the measurement section 2D (see FIG. 3) (the rotation amount detection unit 32 is in the normal mode). It consists of the operating measurement section).

  Here, for example, when selecting the maximum value of the measurement data while the flange portion 2B is rotated by one measurement section 2D, the maximum value selection unit 34 inputs the output of the rotation amount detection unit 32 and rotates. Of the outputs V1, V2,... Of the distance measuring sensor 12 sampled at a predetermined sampling interval from the start time t2 to the end time t3 for one period during which the amount detection unit operates in the normal mode. Measurement data Vmax is calculated and output to the wearing state determination unit 35.

  FIG. 2B is a functional block diagram of the first embodiment of the wearing state determination unit 35 shown in FIG. As shown in the figure, the wearing state determination unit 35 includes a pop-up determination reference value storage unit 41, a subtractor 42 that calculates a difference between the pop-up determination reference value storage unit 41 and the input from the maximum value selection unit 34, and the subtraction. And a comparator 43 that compares the output of the comparator 42 with a predetermined abnormality determination value and outputs the comparison result.

  FIG. 9 is a flowchart of the wearing state determination method according to the present invention, and FIG. 10 is an explanatory diagram thereof. Here, the maximum value selected by the maximum value selector 34 corresponds to the maximum value of the measurement data while the flange portion 2B is rotated by one measurement section 2D, that is, one measurement section 2D. Consider a case where the maximum value of the measurement data is obtained for each rotation amount, and the wearing state is determined based on the change over time.

  In step S51, the mounting state determination unit 35 inputs the output of the maximum value selection unit 34 before the rotation of the tool holder 2 is still low and the rotation detection unit 33 determines the start of rotation. Then, at the time t0 when the rotation detection unit 33 detects the start of rotation, the maximum value of the measurement data of the distance measuring sensor 12 measured immediately before is stored in the pop-out determination reference value storage unit 41 as the pop-out determination reference value.

Then, after the rotation detection unit 33 detects the start of rotation, in step S52, the wearing state determination unit 35 inputs the output of the maximum value selection unit 34, and the pop-up determination reference value stored as the output of the maximum value selection unit 34 each time. Is calculated by the subtractor 42 (step S53). In step S54, the comparator 43 compares the difference ΔM with a predetermined abnormality determination value.
While determining that the difference ΔM between the maximum value of the measurement data and the stored pop-up determination reference value exceeds the predetermined abnormality determination value in step S54 while repeatedly executing the above steps S52 to S54, The mounting state determination unit 35 determines an abnormality in the mounting state of the tool holder 2 in step S55.

The mounting state determination method shown in FIG. 9 has an advantage that abnormality in the mounting state can be detected at high speed. However, the tool holder 2 capable of determining the abnormality is almost the same everywhere except the portion where the surface of the flange 2B is not notched. It is limited to a certain tool holder 2.
In addition, when the tool holder 2 is mounted eccentrically, measurement data may be uneven depending on the measurement section, which may cause erroneous detection due to the influence.

  Therefore, in the mounting state determination method described below, the maximum value selection unit 34 outputs the maximum value of the measurement data while the flange portion 2B is rotated by a plurality of measurement sections 2D. That is, the maximum value of the measurement data is obtained for each rotation amount corresponding to a plurality of measurement sections 2D, and the wearing state is determined based on the change over time. A flowchart of such a wearing state determination method is shown in FIG. 11, and an explanatory diagram thereof is shown in FIG.

At time t0 shown in FIG. 12, the rotation detection unit 33 detects the rotation start of the flange portion 2B, and outputs a rotation start detection signal to the popping-out determination reference value storage unit 41 of the mounting state determination unit 35 (step S61). .
Thereafter, in step S62, the maximum value selection unit 34 inputs measurement data of the distance measuring sensor 12. This operation is performed until the notch detector 36 detects the notch a predetermined number of times (four times in the example shown in FIG. 12) at time t1 (step S63).

  When the notch detection unit 36 detects the notch a predetermined number of times in step S63, the maximum value selection unit 34 extends from time t0 to time t1, that is, until the notch detection unit 36 detects the notch a predetermined number of times. M1, which is the maximum value of the measurement data input from the distance measuring sensor 12, is selected and output to the wearing state determination unit 35 (step S64). The pop-up determination reference value storage unit 41 of the mounting state determination unit 35 is used as a pop-up determination reference value when the measurement data input from the maximum value selection unit 34 is the first data after the rotation of the flange portion 2B is started. Remember.

  Thereafter, in step S65, the maximum value selection unit 34 inputs measurement data of the distance measuring sensor 12. This operation is performed until the notch detection unit 36 detects the notch a predetermined number of times at time t2 (step S66). When the notch detection unit 36 detects the notch a predetermined number of times in step S66, the maximum value selection unit 34 performs measurement from time t1 to time t2, that is, until the notch detection unit 36 detects the notch a predetermined number of times. The maximum value (in this case, M2) of the measurement data input from the distance sensor 12 is selected and output to the wearing state determination unit 35 (step S67).

Thereafter, in step S68, the subtractor 42 of the wearing state determination unit 35 calculates a difference ΔM between the maximum value M2 of the measurement data and the pop-up determination reference value. In step S69, the comparator 43 calculates the difference ΔM and a predetermined value. Compare the abnormality judgment value.
Steps S65 to S69 are repeated, and when the difference ΔM exceeds a predetermined abnormality determination value in step S69, it is determined in step S70 that the mounting state of the tool holder 2 is abnormal.

  At this time, if the number of notches detected until the maximum value selection unit 34 selects the maximum value is set to be larger than the number of times corresponding to one rotation of the flange portion 2B, the distance measuring sensor 12 in a round unit of the flange portion 2B. It is possible to monitor the change over time of the maximum value of the measured data, and to eliminate the influence of eccentricity on the difference in height of the flange 2B surface and the attachment of the tool holder 2.

The above-described wearing state determination method of FIG. 11 may be considered as the following method.
As shown in FIG. 12, the measurement data obtained by the distance measuring sensor 12 is divided into blocks at the notch measurement portion, and this block is divided into groups by a predetermined number.
And the rotation detection part 33 selects the maximum value of the measurement data contained in the first group 1 after detecting the rotation start, and makes this a pop-out determination reference value.
When the maximum value of the measurement data included in the group of measurement data measured after that is selected, and the difference between this maximum value and the pop-up judgment reference value is greater than the predetermined abnormality judgment value, the tool holder 2 to determine whether the wearing state is abnormal.

  Here, if the number of blocks per group is set to be larger than the number of blocks for one rotation of the tool, it becomes possible to eliminate the difference in the height of the flange 2B surface and the influence of eccentricity on the attachment of the tool holder 2. .

  When the tool holder is normally mounted on the spindle, the amount of displacement of the tool holder attached to the spindle hardly changes over time, so the maximum value of the measurement data output by the maximum value selection unit 34 However, when the tool holder is removed from the spindle, the maximum value of the measurement data output from the maximum value selection unit 34 may increase with time. Therefore, if the cumulative value of the difference between the measurement data output at different points in time is calculated, the cumulative value hardly changes when the tool holder is normally mounted on the spindle, whereas the tool holder falls off the spindle. In this case, the cumulative value may increase rapidly.

In the second embodiment of the wearing state determination unit 35 shown in FIG. 2A described below, the cumulative value of the difference between the measurement data output from the maximum value selection unit 34 at different times is calculated. An abnormality in the mounting state of the tool holder on the spindle is determined based on the change over time of the accumulated value.
FIG. 13 is a functional block diagram of a second embodiment of such a wearing state determination unit 35, and FIG. 14 is an operation explanatory diagram thereof.

  As illustrated in FIG. 13, the wearing state determination unit 35 obtains a difference value between the measurement data output from the maximum value calculation unit 34 and the measurement data output before that, and calculates a cumulative value of the difference values. A set of difference accumulation calculation units 61 and 62, a selection unit 63 that alternately distributes and inputs measurement data continuously output from the maximum value calculation unit 34 to the difference accumulation calculation units 61 and 62, and a difference accumulation calculation An adder 73 that adds the outputs of the units 61 and 62, and a comparator 64 that compares the output of the adder 73 with a predetermined abnormality determination value and outputs the comparison result.

The selection unit 63 alternately distributes the measurement data continuously output by the maximum value calculation unit 34 to the difference accumulation calculation units 61 and 62. Therefore, the difference accumulation calculation units 61 and 62 are input with the measurement data continuously output from the maximum value calculation unit 34 one by one. This will be described with reference to FIG.
As shown in FIG. 14A, the flange 2B of the tool holder 2 is provided with two notches 2C at positions opposite to the outer periphery of the flange 2B. Two outer peripheral surface portions (measurement sections A and B) sandwiched between the notches 2C are formed on the outer periphery of the flange 2B, and these two outer peripheral surface portions are also located at positions opposite to the outer periphery of the flange 2B. is doing.

  Accordingly, when the distance to the outer peripheral surface is measured by the distance measuring sensor 12 by rotating the flange 2B, the measurement data is data obtained by measuring the measurement section A and the measurement section B as shown in FIG. Are divided by notch portions, and the maximum value calculation unit 34 determines the maximum values Ma1, Ma2... Of the measurement data measured in the measurement section A, and the maximum values Mb1, Mb2. And are output alternately.

Therefore, when the selection unit 63 alternately distributes the measurement data of the maximum value calculation unit 34 to the difference accumulation calculation units 61 and 62, the difference accumulation calculation units 61 and 62 have one and the other of the measurement sections A and B, respectively. Only measured measurement data is input continuously. That is, only the measurement data measured for the same portion of the flange 2B is input to the difference accumulation calculation unit 61, and the difference accumulation calculation unit 62 also (the portion where the measurement data input to the difference accumulation calculation unit 61 is measured). Only the measurement data measured for the same part of the flange 2B is input.
For example, the difference accumulation calculation unit 61 is continuously input with the maximum values Ma1, Ma2,... Output by the maximum value calculation unit 34 continuously for the measurement interval A, and the difference accumulation calculation unit 62 is for the measurement interval B. The maximum values Mb1, Mb2,... Continuously output from the maximum value calculation unit 34 are continuously input.

Returning to FIG. 13, the previous cumulative data calculation unit 61 (62) stores the measurement data selected and input by the selection unit 63 until the next measurement data is input. ), The subtractor 66 (70) for calculating the difference between the currently input measurement data and the measurement data stored in the previous data storage unit 65 (69), and the accumulated value of the output from the subtractor 66 (70) Is added to the cumulative value storage unit 67 (71), the cumulative value stored in the cumulative value storage unit 67 (71) and the newly calculated output from the subtractor 66 (70), And an adder 68 (72) for calculating a new cumulative value.
Thus, for example, in the above example, the difference accumulation calculation unit 61 (62) is configured to output the maximum values Ma1, Ma2,... (Mb1, Mb2,...) Continuously output from the maximum value calculation unit 34 for the measurement section A (B). The cumulative value of the difference value between two consecutive values is output.

FIG. 15 is a flowchart (part 3) of the wearing state determination method according to the present invention.
In step S71, the difference accumulation calculation unit 61 (62) clears the accumulation value Δca (Δcb) stored in the respective accumulation value storage unit 67 (71). Next, in steps S72 and S73, the difference accumulation calculation unit 61 (62) inputs the first measurement data Ma1 (Mb1) output by the maximum value calculation unit 34 for the measurement section A (B) and is input last time. The data is stored in the previous data storage unit 65 (69) as data Mold (Mbold).

Subsequently, in steps S74 and S75, the difference accumulation calculation unit 61 (62) currently receives the measurement data Ma2 (Mb2...) After the maximum value calculation unit 34 outputs for the measurement section A (B). The measurement data Mannew (Mbnew) is sequentially input.
In step S76, the subtractor 66 (70) determines the difference Δa () between the previously input data Maold (Mbold) stored in the previous data storage unit 65 (69) and the currently input measurement data Mannew (Mbnew). Δb) is calculated.

  In step S77, the adder 68 (72) adds the difference Δa (Δb) to the current accumulated value Δca (Δcb) stored in the accumulated value storage unit 67 (71) to obtain a new accumulated value. Is calculated. Further, in step S78, the adder 73 calculates a total cumulative value Δcab = Δca + Δcb obtained by adding the cumulative values Δca and Δcb.

In step S79, the comparator 64 determines whether or not the total accumulated value Δcab exceeds a predetermined abnormality determination value. When the total accumulated value Δcab does not exceed the predetermined abnormality determination value, the previous data storage unit 65 is determined. The data Maold (Mbold) stored in (69) is updated to the currently input measurement data Mannew (Mbnew) (step S80), and steps S74 to S80 are repeated.
When the comparator 64 determines in step S79 that the total accumulated value Δcab has exceeded a predetermined abnormality determination value, it determines in step S81 that the mounting state of the tool holder 2 is abnormal.

  The total cumulative value Δcab obtained by adding the cumulative values Δca and Δcb calculated for a plurality of different sections A and B on the outer periphery of the flange 2B as in the configuration example of FIG. 13 and the notch installation mode of FIG. By comparing with a predetermined abnormality determination value, the cumulative value Δcab increases faster than the cumulative value Δca calculated for one section, and it becomes possible to find an abnormality in the wearing state at an early stage.

  Further, by calculating the total accumulated value Δcab, it is possible to remove the influence when the tool holder 2 slides with respect to the main shaft 3. That is, the tool holder 2 falls off while gradually sliding with respect to the main shaft 3. Since this slide also occurs in the direction of rotation of the tool holder 2, even if the mounting position of the tool holder 2 is actually large, the measurement data measured by the distance measuring sensor 12 in the same section is changed over time. It may not change greatly. This is shown in FIG.

  In the attachment state shown in FIG. 16B, the rotation shaft 2E of the tool holder 2 is further away from the rotation shaft 3C of the main shaft 3 than in the attachment state shown in FIG. It is more out of alignment. However, in the state shown in FIG. 16B, the mounting position of the tool holder 2 is shifted in the rotation direction with respect to the main shaft 3 as compared with the state shown in FIG. The azimuth angle of the rotation axis 3C of the main shaft 3 as viewed from 2E is different. Due to this influence, no difference occurs in the measurement data measured by the distance measuring sensor 12. As described above, when only a part of the outer circumference of the flange 2B is measured, the rotation occurs even when the distance between the rotation shaft 2E of the tool holder 2 and the rotation shaft 3C of the main shaft 3 is increasing. It is conceivable that there is no significant change in the maximum value of the measurement data due to the sliding of the mounting position in the rotation direction.

Therefore, when only a part of the outer circumference of the flange 2B is measured by calculating the total cumulative value Δcab obtained by adding the cumulative values Δca and Δcb calculated for a plurality of different sections A and B on the outer circumference of the flange 2B. It is possible to reduce the influence of the slide on the rotation direction that can occur.
Further, as in the above embodiment, for the sections A and B that cover the entire outer periphery of the flange 2B excluding the notch, the cumulative values Δca and Δcb are calculated, respectively, and the total cumulative value Δcab obtained by adding these is calculated. Since the change in the maximum value of the displacement amount of the flange 2B detected while the flange 2B makes one round can be monitored, the influence of the slide in the rotation direction can be eliminated.
In the configuration example of FIG. 13 and the notch installation mode of FIG. 14A described above, an example is shown in which two notches are provided on the outer peripheral surface of the flange 2B and only two measurement sections are defined. The present invention is not limited to this, and three or more measurement sections are defined by providing three or more cutouts on the outer peripheral surface of the flange 2B, and the cumulative values Δca, Δcb,... A total cumulative value obtained by adding all or part of the above may be compared with a predetermined abnormality determination value.

  The present invention can be suitably used for a machine tool device having a rotating shaft, particularly a machine tool using a tool holder such as a machining center (hereinafter abbreviated as “MC”).

It is a block diagram of the Example of the chuck | zipper mistake detection apparatus which concerns on this invention. (A) is a functional block diagram of the data processing apparatus shown in FIG. 1, and (B) is a functional block diagram of the first embodiment of the wearing state determination unit shown in (A). It is a top view of the tool holder which has a notch in a flange part. It is an operation | movement flowchart of the rotation amount detection part shown to (A) of FIG. It is operation | movement explanatory drawing of the rotation amount detection part shown to (A) of FIG. It is an operation | movement flowchart of the rotation detection part shown to (A) of FIG. It is operation | movement explanatory drawing of the rotation detection part shown to (A) of FIG. It is operation | movement explanatory drawing of the maximum value selection part shown to (A) of FIG. It is a flowchart (the 1) of the mounting state determination method which concerns on this invention. It is explanatory drawing of the mounting state determination method shown in FIG. It is a flowchart (the 2) of the mounting state determination method which concerns on this invention. It is explanatory drawing of the mounting state determination method shown in FIG. It is a functional block diagram of 2nd Example of the mounting state determination part shown to (A) of FIG. It is operation | movement explanatory drawing of the mounting state determination part shown in FIG. It is a flowchart (the 3) of the mounting state determination method which concerns on this invention. It is explanatory drawing of the shift | offset | difference of the rotation direction of the mounting state of a tool holder. It is explanatory drawing of a tool holder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tool 2 Tool flange 2A Fitting part 2B Flange part 3 Main shaft 3A Part to be fitted 5 Head 6 Bracket 10 Chuck mistake detection device 10
12 Distance Sensor 14 Data Processing Device 32 Rotation Amount Detection Unit

Claims (9)

In a machine tool that mounts a tool holder to which a tool is attached to a spindle and drives the spindle to rotate the workpiece,
Distance measuring means for measuring the distance from a predetermined measurement point to the outer peripheral surface of the flange of the tool holder attached to the spindle;
A rotation amount detecting means for detecting the rotation amount of the flange;
Maximum value selection means for selecting a maximum value for each predetermined rotation amount of the measurement data obtained by the distance measurement means based on the rotation amount detected by the rotation amount detection means;
Based on the change over time of the maximum value, mounting state determination means for determining an abnormality in the mounting state of the tool holder to the spindle,
A machine tool comprising:   The machine tool according to claim 1, wherein the rotation amount detecting means detects a rotation amount of the flange by detecting a position mark provided on an outer peripheral surface of the flange. The position mark is a notch provided on the outer peripheral surface of the flange,
The machine tool according to claim 2, wherein the rotation amount detection means detects the notch based on measurement data of the distance measurement means.   When the maximum value measured at a certain point of time is greater than a predetermined threshold value by a predetermined threshold or more, the mounting state determination unit is abnormal in the mounting state of the tool holder on the spindle It determines with it being, The machine tool as described in any one of Claims 1-3 characterized by the above-mentioned.   The machine tool according to claim 1, wherein the predetermined rotation amount is one rotation or more.   The mounting state determination means calculates a cumulative value of differences between the maximum values measured at different time points, and when the cumulative value becomes larger than a predetermined threshold, the mounting state of the tool holder on the spindle is determined. It determines with it being abnormal, The machine tool as described in any one of Claims 1-3 characterized by the above-mentioned.   The machine tool according to claim 6, wherein the mounting state determination unit calculates a cumulative value of differences between the maximum values measured at different time points on the same portion of the outer peripheral surface of the flange.   The mounting state determining means calculates the cumulative value for each of a plurality of different portions of the outer peripheral surface of the flange, and when the sum of the cumulative values becomes greater than a predetermined threshold, the tool holder is moved to the spindle. The machine tool according to claim 7, wherein the mounting state is determined to be abnormal. In a machine tool that attaches a tool holder to a main shaft and rotationally drives the main shaft,
Measure the distance from a predetermined measurement point to the outer peripheral surface of the flange of the tool holder attached to the spindle,
Detecting the amount of rotation of the flange;
Based on the detected rotation amount, select the maximum value for each of the predetermined rotation amount of the measured measurement data,
Based on the change over time of the selected maximum value, an abnormality in the mounting state of the tool holder on the spindle is determined.
A tool holder mounting state abnormality determination method for a machine tool having the spindle.

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