JP2007260885A - Inclination detecting method and inclination detecting device of tool holder in machine tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a detecting method and detecting device which highly accurately detects an inclination of a tool holder, without using an expensive sensor, when nipping foreign matter such as cutting chips between a main spindle and the tool holder. <P>SOLUTION: An eddy current sensor 5 is arranged so that a head surface 5a of the eddy current sensor 5 is opposed from the oblique direction to a side surface 232a of a flange part 232 of the tool holder 2. When rotating the main spindle 1, the inclination of the tool holder 2 is detected on the basis of output of the eddy current sensor 5 generated by a change in the relative positional relationship between the flange part 232 of the tool holder 2 and the head surface 5a of the eddy current sensor 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method and apparatus for detecting the tilt of a tool holder relative to a rotation axis of a main shaft in a machine tool.

  In a machine tool such as a machining center equipped with an automatic tool changer, tools are automatically changed according to a machining process. Various tools are each held in a tool holder and stored in a tool magazine. The automatic tool changer selects a predetermined tool holder, removes it from the tool magazine, and automatically mounts it on the spindle. However, chips tend to adhere to the main shaft, and when the tool holder is mounted on the main shaft, if the chips are sandwiched between the tool holder and the main shaft, the tool holder is inclined with respect to the rotation axis of the main shaft, When the main shaft is rotated in this state, tool deflection occurs. For this reason, the machining accuracy of the workpiece is adversely affected, and in some cases, it may lead to a serious accident such as dropping of the tool holder. For this reason, when the tool holder is mounted on the spindle, various ingenuities have been made to detect the inclination of the tool holder due to the chip being caught and prevent machining defects.

  For example, Patent Document 1 listed below discloses a tool holder inclination detection device using an eddy current sensor. In this apparatus, the eddy current sensor is disposed to face the side surface of the flange portion of the tool holder. Since the impedance formed between the sensor head and the flange portion changes according to the gap between them, the inclination of the tool holder can be detected by measuring the impedance change when the main shaft is rotated. .

  Further, Patent Document 2 described later also discloses an inclination detection device in which an eddy current sensor is disposed to face a side surface of a flange portion of a tool holder. In this device, the change in the distance from the sensor head to the side surface of the flange portion is measured by an eddy current sensor corresponding to the rotation angle of the tool holder, and this measurement data is analyzed by FFT (Fast Fourier Transform). A fundamental frequency component is extracted and its amplitude is calculated. Then, the inclination of the tool holder is calculated from the amplitude of the fundamental frequency component.

JP 2002-331442 A Japanese Patent Laid-Open No. 2002-200542

  Patent Document 1 and Patent Document 2 described above use an eddy current sensor arranged opposite to the side surface of the flange portion of the tool holder, and detect the inclination of the tool holder based on a change in the distance between the sensor head and the tool holder. Is. However, since these prior arts use only the change in distance in the direction orthogonal to the rotation axis of the main shaft, the change in distance due to the inclination of the tool holder is very small, and the output change of the eddy current sensor, that is, the sensitivity is small. It was not enough. For this reason, it was difficult to detect the inclination of the tool holder due to the inclusion of foreign matter such as chips with high accuracy. In addition, in order to increase the sensitivity and detect a displacement of several tens of microns, a highly sensitive displacement sensor must be used, resulting in a problem that the apparatus becomes expensive.

  Therefore, the present invention is a detection capable of detecting the tilt of the tool holder with high accuracy without using an expensive sensor when foreign matter such as chips is caught between the spindle and the tool holder. It is an object to provide a method and a detection device.

  In the tool holder tilt detection method according to the present invention, an eddy current sensor is disposed in the vicinity of the tool holder attached to the main spindle of the machine tool, and the tool holder relative to the rotation axis of the main spindle is based on the output of the eddy current sensor. Inclination detection method, the eddy current sensor is arranged so that the head surface of the eddy current sensor faces the side surface of the flange portion of the tool holder so as to face the oblique direction or partially face the lateral direction, When the spindle is rotated, the tilt of the tool holder is detected based on the output of the eddy current sensor generated by the change in the relative positional relationship between the flange portion of the tool holder and the head surface of the eddy current sensor. .

  In this case, when the main shaft is rotated, the distance or the facing area between the flange portion of the tool holder and the head surface of the eddy current sensor greatly changes according to the inclination of the tool holder. Compared to the conventional method using only the change in the distance in the direction orthogonal to the rotation axis, a large change in output can be obtained from the eddy current sensor. As a result, the sensitivity is improved, and the tilt of the tool holder due to foreign matters such as chips can be detected with high accuracy. Further, even if a highly sensitive displacement sensor is not used, the conventional eddy current sensor can be used and can be realized simply and inexpensively by simply changing the position of the sensor.

  Two embodiments of the tool holder tilt detection method of the present invention are conceivable. The first embodiment is a method that mainly uses a change in the distance between the flange portion and the sensor head. In this method, the eddy current sensor is inclined by a predetermined angle with respect to the direction orthogonal to the rotation axis of the main shaft. The head surface of the eddy current sensor is opposed to the side surface of the flange portion of the tool holder from an oblique direction. Then, the inclination of the tool holder is detected based on the output of the eddy current sensor that is generated when the predetermined portion of the flange portion is displaced in the direction of the head surface of the eddy current sensor when the main shaft is rotated.

  In the first embodiment, by arranging the eddy current sensor obliquely in the direction in which the displacement amount of the predetermined portion in the flange portion of the tool holder is maximized, the output change of the eddy current sensor is maximized and the sensitivity is improved. It is possible to detect the tilt of the tool holder with high accuracy. For example, the sensitivity can be improved by about 77% as compared with a conventional case where the eddy current sensor is opposed to the side surface of the flange portion from the lateral direction.

  The second embodiment is a method that mainly uses a change in the overlap area (opposed area) between the flange portion and the sensor head. In this method, the eddy current sensor is arranged in a direction orthogonal to the rotation axis of the main shaft. By doing so, the head surface of the eddy current sensor is partially opposed to the side surface of the flange portion of the tool holder from the lateral direction. Then, when the spindle is rotated, the tilt of the tool holder is detected based on the output of the eddy current sensor generated by the change in the overlap area between the head surface of the eddy current sensor and the side surface of the flange portion of the tool holder. To do.

  In the second embodiment, when the spindle is rotated, the distance between the head surface of the sensor and the side surface of the flange portion changes due to the inclination of the tool holder, and the output of the eddy current sensor changes. The overlap area between the head surface and the side surface of the flange portion changes, and the output of the eddy current sensor changes. As a result, a large output change is obtained from the eddy current sensor due to both a change in distance and a change in the overlap area, and the sensitivity is improved and the tool holder tilt can be detected with high accuracy.

  The tilt detection device of the present invention used in the first embodiment includes an eddy current sensor arranged in the vicinity of a tool holder attached to the spindle of a machine tool, and based on the output of the eddy current sensor, An apparatus for detecting the inclination of the tool holder with respect to the rotation axis, wherein the eddy current sensor is disposed at a predetermined angle with respect to a direction perpendicular to the rotation axis of the main shaft, thereby being arranged on the side surface of the flange portion of the tool holder. On the other hand, the head surface of the eddy current sensor is opposed from an oblique direction.

  The tilt detection device of the present invention used in the second embodiment includes an eddy current sensor arranged in the vicinity of a tool holder attached to the spindle of a machine tool, and based on the output of the eddy current sensor, An apparatus for detecting a tilt of a tool holder with respect to a rotating shaft, wherein the eddy current sensor is disposed in a direction perpendicular to the rotating shaft of the main shaft, whereby the head of the eddy current sensor is placed against the side surface of the flange portion of the tool holder. The surfaces are partially opposed in the lateral direction so that the overlap area between the head surface and the side surface of the flange portion is approximately half the area of the head surface.

  In the tilt detection apparatus of the present invention, the flange portion of the tool holder may be constituted by a disc that is detachably attached to the tool holder. According to this, the position of the eddy current sensor can be arbitrarily set according to the disk, and measurement can be performed without being influenced by the notch provided in the tool holder, and the sensor output This makes signal processing easier.

  According to the present invention, the distance between the flange portion of the tool holder and the head surface of the eddy current sensor and the change in the facing area are increased, and the sensitivity is improved. The inclination of the tool holder due to foreign matters such as chips sandwiched between the holder and the holder can be detected with high accuracy.

  FIG. 1 is an example of a tool holder used in the present invention, and shows a state in which a tool holder is mounted on a main shaft. Reference numeral 1 denotes a main shaft of a machine tool such as a machining center, 2 denotes a tool holder attached to the main shaft 1, and 3 denotes a tool held by the tool holder 2. The main shaft 1 is provided with a boss portion 11 and a concave portion 12. The tool holder 2 includes a fitting portion 21 that fits into the concave portion 12 of the main shaft 1 and a flange portion 23 that joins to the boss portion 11 of the main shaft 1. The flange portion 23 includes two flange portions 231 and 232 sandwiching the groove 22. Reference numeral 24a denotes one of a pair of chuck notches formed in the flange portion 23, which engages with an arm of a tool changer (not shown) during automatic tool change. Reference numeral 25 denotes a notch for positioning the tool holder 2, and its position is detected by a sensor (not shown). The structure of the spindle 1 and the tool holder 2 as described above is the same as the conventional one.

  FIG. 2 shows a state in which foreign matter 4 such as chips is sandwiched between the end surface 13 of the boss portion 11 of the spindle 1 and the flange portion 231 of the tool holder 2. 2, illustration of the tool 3 of FIG. 1 is omitted (the same applies to the following drawings). In this case, due to the presence of the foreign matter 4, the rotation shaft 2 x of the tool holder 2 is inclined to the left by an angle θ with respect to the rotation shaft 1 x of the main shaft 1. Then, when the main shaft 1 rotates around the rotation shaft 1x in this state, the flange portion 23 swings in the F direction as shown in FIG. 3 in the numbers 1 → 2 → 3 → 2 → 1 → 2. To do.

  If the location where the foreign material 4 is sandwiched is the position shown in FIG. 4A, the rotation angle φ of the main shaft 1 at this time is set to φ = 0 (reference position) as shown in FIG. 4B. When the main shaft 1 rotates in the direction of the arrow in FIG. 4B, the foreign matter 4 also moves accordingly. When the foreign material 4 comes to the position shown in FIG. 5A, the rotation angle φ of the main shaft 1 becomes φ = π (half rotation position) as shown in FIG. 5B. At this time, the rotation shaft 2x of the tool holder 2 is inclined to the right by the angle θ with respect to the rotation shaft 1x of the main shaft 1. When the main shaft 1 further rotates halfway (φ = 2π), the foreign matter 4 returns to the position shown in FIG. In FIG. 5A, 24b represents the other of the chuck notches.

From the above, in the process in which the main shaft 1 makes one rotation, the tool holder 2 swings left and right by an angle 2θ. FIG. 6A is a diagram showing the state of the swing of the tool holder 2, and FIG. 6B is a cross-sectional view taken along line AA of FIG. 6A. Here, since the angle formed between the boss portion 11 of the main shaft 1 and the flange portion 23 is equal to the inclination angle θ of the tool holder 2, the diameter of the foreign matter 4 is d, and the diameter of the flange portion 23 (= the diameter of the boss portion 11). When D is D, the following relationship is established between them.

また、Δｚ＝ｄであるから、式（１）、（２）より、

となる。 On the other hand, in FIG. 7 in which the K portion of FIG. 6 is enlarged, the measurement point P is taken at the edge portion of the flange portion 232, and the r axis and the z axis are set as shown in the figure. The r-axis is an axis orthogonal to the rotation axis 1x (FIG. 6) of the main shaft 1, and the z-axis is an axis parallel to the rotation axis 1x of the main shaft 1. Δr is the maximum amplitude amount in the r-axis direction of the P point, Δz is the maximum amplitude amount in the z-axis direction of the P point, ΔL is the maximum displacement amount of the P point, and α is the angle formed by the displacement direction of the P point and the r-axis direction. It is. s is the distance from the upper end of the flange portion 231 to the point P. In FIG.

Moreover, since Δz = d, from the equations (1) and (2),

It becomes.

式（３）、（４）、（５）よりφを消去してｒとｚの関係を求めると、次式のようになる。

FIG. 8 shows a change in the amplitude of the point P during one rotation of the main shaft 1 (0 ≦ φ ≦ 2π). (A) shows the amplitude in the z-axis direction, and (b) shows the amplitude in the r-axis direction. As shown in the figure, the point P simply vibrates in the r-axis direction and the z-axis direction, and each amplitude is expressed by the following equation.

If the relationship between r and z is determined by eliminating φ from the equations (3), (4), and (5), the following equation is obtained.

  The relationship of equation (6) is represented in a graph as shown in FIG. 9, and the point P swings on the locus shown in FIG. Here, since tan α = Δz / Δr from FIG. 7 and Δz / Δr = D / 2s from equation (3), tan α = D / 2s. That is, the angle α of the swinging direction of the point P with respect to the r-axis direction depends only on the size (D, s) of the tool holder 2 and does not depend on the diameter d of the foreign matter.

Now, assuming that the dimensions of D and s of the tool holder 2 are D = 63 mm and s = 21.5 mm, the value of the angle α is as follows.
α = tan ⁻¹ (D / 2s) = tan ⁻¹ (63/43) = 55.7 °
Therefore, it can be understood that the displacement amount at the point P becomes the maximum value ΔL when the swinging direction of the point P forms an angle of about 56 ° with respect to the r-axis direction. Therefore, if the displacement amount of the point P is measured by the sensor from this direction, the inclination of the tool holder 2 can be detected most efficiently. Since the maximum displacement amount ΔL at point P at this time is in a relationship of ΔL> Δr as compared with the amplitude Δr in the r-axis direction, it is better to measure ΔL than to measure Δr as in the prior art. A large change in output is obtained with respect to the fluctuation of the rotation, and the sensitivity is improved.

  FIG. 10 shows the inclination detecting device of the first embodiment in which the eddy current sensor 5 for detecting the displacement amount at the point P is arranged at an angle of 56 ° with respect to the r-axis direction based on the principle as described above. . The eddy current sensor 5 is attached to, for example, a mounting plate fixed to a headstock (not shown). In this state, the head surface 5a of the eddy current sensor 5 faces the side surface 232a of the flange portion 232 of the tool holder 2 from an oblique direction. The eddy current sensor 5 is a known eddy current sensor. The eddy current sensor 5 has a built-in coil. When a high frequency current flows through the coil, an eddy current flows through the flange portion 232 due to the generated high frequency magnetic field, and the impedance of the coil changes. Since this impedance changes according to the distance between the eddy current sensor 5 and the flange portion 232, it is possible to detect the displacement amount at the point P by detecting the change in the output of the eddy current sensor 5 based on the impedance change. The inclination (angle θ) of the tool holder 2 can be detected from the displacement amount of the point P. As the inclination of the tool holder 2 increases, the amount of displacement at point P increases.

From FIG. 9, since ΔL · sin α = d, the theoretical value of the displacement amount ΔL at the point P is as follows.

  Now, for example, the displacement amount ΔL at point P corresponding to the output voltage 1 V of the eddy current sensor 5 is 203 μm, and a shim 6 made of a metal plate as shown in FIG. The measurement time t, the output voltage V, and the displacement amount ΔL when the tool holder 2 is rotated twice in about 5 seconds per cycle and the thickness d of the shim 6 is changed every 10 μm from 10 to 100 μm. 11A to 11C are represented as graphs. A sine curve at the bottom of the waveform represents the temporal displacement of point P. As shown by A, B, and C in the figure, there are three types of waveform breaks, because this is because the notch portions 24a, 24b, and 25 are provided in the flange portion 23 of the tool holder 2. It is. At these notches, the output voltage waveform is saturated. However, in the present invention, when calculating the displacement amount ΔL, the difference ΔV between the maximum value and the minimum value of the voltage is read from the sine curve on the waveform, and ΔV is converted into the displacement amount ΔL. Even if there is a break, there is no significant effect. For example, by setting a threshold value for the output voltage and extracting only signals below the threshold value, waveform breaks can be ignored.

  As an example, when the shim 6 with d = 60 μm is sandwiched, the output voltage V and the displacement amount ΔL are as shown in FIG. 11B (f). Here, since 1V = 203 μm, the difference between the maximum value and the minimum value of the voltage is ΔV = 0.470 [V] from FIG. 12 which is an enlarged view of FIG. 11B (f). Accordingly, the displacement amount is ΔL = 203 × 0.470 = 95.4 [μm]. In this way, the displacement amount ΔL of the point P when the thickness d of the shim 6 is changed every 10 μm can be obtained from the measured value of ΔV. A solid line I in the graph of FIG. 14 represents the relationship between the displacement amount ΔL obtained from the calculation result and the thickness d of the shim 6.

By the way, as described above, the theoretical value of the displacement amount ΔL is expressed by the equation (7). However, the equation (7) assumes that the foreign matter 4 is caught at the end of the tool holder 2 as shown in FIG. This is the calculation formula when However, when the measurement is performed using the shim 6 instead of the foreign material 4, as shown in FIG. 13A, the shim 6 is inserted between the spindle 1 and the tool holder 2, for example, 7.5 mm. The inclination of the tool holder 2 is increased. From FIG. 13B, since d ′ / d = 63 / (63−7.5), d ′ = 1.14d, and the theoretical value equation when the shim 6 is sandwiched is as follows: Become.

となる。 When the theoretical value of the displacement amount ΔL is obtained from the above equation (8) and expressed in a graph, it is as shown by a broken line II in FIG. A broken line III in FIG. 14 indicates a theoretical value of the displacement amount Δr by the displacement measurement in the r-axis direction by the conventional method. The theoretical value of Δr is from equation (3):

It becomes.

From the above, the theoretical value of the amount of displacement Δr when the measurement is performed with the eddy current sensor 5 facing the side 232a of the flange portion 232 of the tool holder 2 from the side as in the prior art, as in the present invention. In comparison with the theoretical value of the displacement ΔL when the eddy current sensor 5 is tilted by 56 °, the equation (8) and equation (9)
ΔL / Δr = 1.375d / 0.778d = 1.767
Thus, it can be seen that the displacement amount of the present invention is about 1.77 times larger than the conventional one, and the sensitivity is improved by 77%.

  As described above, according to the first embodiment described above, a large output change is obtained from the eddy current sensor 5, the sensitivity is improved, and the inclination of the tool holder 2 due to foreign matters such as chips is detected with high accuracy. Can do. Further, even if an expensive high-sensitivity type displacement sensor is not used, it can be realized simply and inexpensively by using a conventional eddy current sensor and changing the position of the sensor.

  The output voltage of the eddy current sensor 5 is given to a detection circuit (not shown), and the inclination of the tool holder 2 is detected based on this output voltage by the detection circuit. When the inclination amount exceeds a certain value, the detection circuit outputs an abnormal signal, and control such as stopping the rotation of the spindle 1 is performed based on the abnormal signal.

  In the above example, the mounting angle α of the eddy current sensor 5 is set to about 56 ° using the tool holder 2 having the dimensions of D = 63 mm and s = 21.5 mm. However, the tool holder used in the present invention is used. Of course, 2 is not limited to this size, and the angle α takes different values depending on the values of D and s. An angle adjusting mechanism for changing the mounting angle α of the eddy current sensor 5 may be provided so as to be compatible with tool holders having various dimensions.

  Further, in FIG. 10, the eddy current sensor 5 is disposed in the vicinity of the flange portion 23 originally provided in the tool holder 2, but as shown in FIG. 15, a disk 26 is detachably attached to the tool holder 2, The disk 26 may be a flange portion. In this case, the mounting position of the eddy current sensor 5 can be arbitrarily set according to the disk 26. Further, by making the diameter of the disk 26 larger than the diameter of the flange portion 23, the eddy current sensor 5 can be disposed away from the main body of the tool holder 2, and the eddy current sensor 5 does not get in the way when changing the tool. Can be. Further, since the measurement can be performed without being affected by the notches 24a, 24b, 25 and the like provided in the tool holder 2, the waveform breaks as shown in FIGS. Signal processing of the output of the sensor 5 becomes easy.

  Next, a second embodiment of the present invention will be described. FIG. 16 is a diagram illustrating an inclination detection apparatus according to the second embodiment. In the second embodiment, as shown in FIG. 16A, the eddy current sensor 5 is arranged in a direction orthogonal to the rotation axis 1 x of the main shaft 1, and the eddy current sensor is disposed on the side surface 232 a of the flange portion 232 of the tool holder 2. 5 head surfaces 5a are partially opposed from the right lateral direction (so as not to overlap completely). The eddy current sensor 5 is attached to, for example, a mounting plate fixed to a headstock (not shown). dx represents the distance between the head surface 5a and the side surface 232a.

  The principle of the second embodiment is as follows. The eddy current sensor 5 is moved from the position indicated by the broken line in FIG. 16A, that is, from the position where the head surface 5a and the side surface 232a of the flange portion 232 do not face each other (overlap area = 0). Let us consider a case of moving in the direction parallel to Output when the diameter of the head surface 5a of the eddy current sensor 5 is w = 5.4 mm and the eddy current sensor 5 is moved from the position of the broken line (z = 0) to the position of z = 5.4 mm at intervals of 0.2 mm. When the change in voltage is measured in each case of dx = 0.5, dx = 0.7, dx = 0.9, dx = 1.1, dx = 1.3 (unit: mm), as shown in FIG. become. As the eddy current sensor 5 moves in the z direction, the overlap area between the head surface 5a of the sensor and the side surface 232a of the flange portion 232 gradually increases, and the output voltage V decreases accordingly.

  As can be seen from FIG. 17, the slope of the output voltage V becomes the largest in the vicinity of z = 2.5 indicated by the broken line, and the vibration of the tool holder 2 can be detected most sensitively in this vicinity. At this time, the value of z corresponds to about half of the diameter w (= 5.4 mm) of the head surface 5a of the eddy current sensor 5. Therefore, as shown in FIGS. 16B and 16C, the overlap area between the head surface 5a of the eddy current sensor 5 and the side surface 232a of the flange portion 232 is approximately half the area of the head surface 5a. If the eddy current sensor 5 is disposed, the change in the output voltage V when the flange portion 23 is displaced in the z direction due to the inclination of the tool holder 2 is maximized, and the sensitivity is improved.

  Further, as shown in FIG. 17, the smaller the distance dx between the head surface 5a of the eddy current sensor 5 and the side surface 232a of the flange portion 232, the larger the inclination of the output voltage V, and the more sensitive the vibration of the tool holder 2 can be detected. I understand. Therefore, it is desirable that the eddy current sensor 5 be installed as close as possible to the tool holder 2 as long as it does not interfere with the tool holder 2 during automatic tool change.

  As shown in FIG. 18, when foreign matter 4 such as chips is sandwiched between the boss portion 11 of the main shaft 1 and the flange portion 231 of the tool holder 2, when the main shaft 1 rotates, the flange portion 23 is It swings in the F direction as numbers 1 → 2 → 3 → 2 → 1 → 2. As the flange portion 23 swings as 1 → 2 → 3, the overlap area decreases. At the same time, the distance dx between the eddy current sensor 5 and the flange portion 232 is increased. From FIG. 17, when the overlap area decreases (that is, when z decreases), the output voltage V of the sensor 7 increases, and the output voltage V increases even when the distance dx increases. That is, a larger change in the output voltage V can be obtained by using two of the change in the overlap area and the change in the distance.

  Specifically, when the diameter of the eddy current sensor 5 is w = 5.4 mm, the eddy current sensor 5 is installed at a position where dx = 0.5 mm and z = 2.5 mm, and as in the first embodiment, The main shaft 1 is rotated with the shim 6 (FIG. 13) in place of the foreign matter 4, and the output voltage waveform of the eddy current sensor 5 is measured to obtain the difference ΔV between the maximum value and the minimum value of the output voltage. The results are as shown by 19 solid lines IV, and it was found that substantially the same effect as the solid line I representing the measurement results of the first embodiment was obtained.

  Thus, according to the second embodiment described above, a large output change can be obtained from the eddy current sensor 5 by utilizing changes in both the overlap area and the distance, the sensitivity can be improved, and chips and the like can be obtained. It is possible to detect the inclination of the tool holder 2 due to the foreign matter with high accuracy. Further, even if an expensive high-sensitivity type displacement sensor is not used, it can be realized simply and inexpensively by using a conventional eddy current sensor and changing the position of the sensor.

  The output voltage of the eddy current sensor 5 is given to a detection circuit (not shown), and the inclination of the tool holder 2 is detected based on this output voltage by the detection circuit. When the inclination amount exceeds a certain value, the detection circuit outputs an abnormal signal, and control such as stopping the rotation of the spindle 1 is performed based on the abnormal signal.

  Also in the second embodiment, the disc holder 26 as shown in FIG. 15 is used as a flange, and the inclination of the tool holder 2 is changed by utilizing the change in the overlap area between the side surface 26 a of the disc 26 and the eddy current sensor 5. Can be detected.

  In the first embodiment, the description has been made by paying attention only to the change in the distance. However, by arranging the eddy current sensor 5 at an angle, the flange portion 232 of the tool holder 2 can be connected to the flange portion 232 as in the second embodiment. It is considered that the overlap area also changes between the two, and this is one of the reasons why the measured value I of the displacement ΔL exceeds the theoretical value II in FIG.

  In each of the embodiments described above, the machining center is taken as an example of the machine tool. However, the present invention can be applied to all machine tools provided with an automatic tool changer in addition to the machining center.

It is a figure which shows the state which mounted | wore the main shaft with the tool holder. It is a figure which shows the state in which the foreign material was pinched | interposed between the main axis | shaft and the tool holder. It is a figure explaining rocking | fluctuation of the flange part of a tool holder. It is a figure explaining the rotation angle of a main axis | shaft, and the position of a foreign material. It is a figure explaining the rotation angle of a main axis | shaft, and the position of a foreign material. It is a figure which shows the mode of deflection of a tool holder. It is the figure which expanded the K section of FIG. It is a figure showing the change of the amplitude of P point during 1 rotation of a main axis | shaft. It is a figure showing the movement locus | trajectory of P point. It is a figure which shows the inclination detection apparatus of 1st Embodiment of this invention. It is a figure showing the measurement result of output voltage and displacement. It is a figure showing the measurement result of output voltage and displacement. It is a figure showing the measurement result of output voltage and displacement. It is an enlarged view of FIG. 11B (f). It is a figure which shows the state which interposed the shim between the main axis | shaft and the tool holder. It is a figure showing the relationship between the amount of displacement and the thickness of a shim. It is a figure which shows the other example of a flange. It is a figure which shows the inclination detection apparatus of 2nd Embodiment of this invention. It is a figure showing the relationship between the position of an eddy current sensor, and output voltage. It is a figure explaining the rocking | fluctuation of a flange part, and the change of an overlap area. It is a figure showing the relationship between the difference of an output voltage, and the thickness of shim.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main shaft 1x Rotating shaft 2 Tool holder 2x Rotating shaft 3 Tool 4 Foreign object 5 Eddy current sensor 5a Head surface 23,231,232 Flange part 232a Side surface 26 Disc

Claims (6)

In a method of arranging an eddy current sensor in the vicinity of a tool holder attached to a spindle of a machine tool, and detecting an inclination of the tool holder with respect to a rotation axis of the spindle based on an output of the eddy current sensor,
The eddy current sensor is arranged so that the head surface of the eddy current sensor is opposed to the side surface of the flange portion of the tool holder from the oblique direction or partially opposed from the lateral direction,
Detecting the tilt of the tool holder based on the output of the eddy current sensor caused by a change in the relative positional relationship between the flange portion of the tool holder and the head surface of the eddy current sensor when the spindle is rotated. A tilt detection method of a tool holder in a machine tool characterized by the above. In a method of arranging an eddy current sensor in the vicinity of a tool holder attached to a spindle of a machine tool, and detecting an inclination of the tool holder with respect to a rotation axis of the spindle based on an output of the eddy current sensor,
By arranging the eddy current sensor so as to be inclined at a predetermined angle with respect to a direction orthogonal to the rotation axis of the main shaft, the head surface of the eddy current sensor is inclined from the side surface of the flange portion of the tool holder. Face each other
The tilt of the tool holder is detected based on the output of the eddy current sensor generated when the predetermined portion of the flange portion is displaced in the direction of the head surface of the eddy current sensor when the main shaft is rotated. Of tilting a tool holder in a machine tool. In a method of arranging an eddy current sensor in the vicinity of a tool holder attached to a spindle of a machine tool, and detecting an inclination of the tool holder with respect to a rotation axis of the spindle based on an output of the eddy current sensor,
By disposing the eddy current sensor in a direction orthogonal to the rotation axis of the main shaft, the head surface of the eddy current sensor is partially opposed from the lateral direction to the side surface of the flange portion of the tool holder,
Based on the output of the eddy current sensor generated by changing the overlap area between the head surface of the eddy current sensor and the side surface of the flange portion of the tool holder when the spindle is rotated, the tilt of the tool holder is adjusted. A tool holder tilt detection method for a machine tool, wherein the tool holder is detected. In an apparatus that includes an eddy current sensor disposed in the vicinity of a tool holder attached to a spindle of a machine tool, and detects an inclination of the tool holder with respect to a rotation axis of the spindle based on an output of the eddy current sensor,
By arranging the eddy current sensor so as to be inclined at a predetermined angle with respect to the direction orthogonal to the rotation axis of the main shaft, the head surface of the eddy current sensor is inclined from the side surface of the flange portion of the tool holder. A tool holder inclination detecting device in a machine tool characterized by being opposed to each other. In an apparatus that includes an eddy current sensor disposed in the vicinity of a tool holder attached to a spindle of a machine tool, and detects an inclination of the tool holder with respect to a rotation axis of the spindle based on an output of the eddy current sensor,
By disposing the eddy current sensor in a direction perpendicular to the rotation axis of the main shaft, the head surface of the eddy current sensor is partially opposed to the side surface of the flange portion of the tool holder from the lateral direction, and A tool holder inclination detecting device in a machine tool, wherein an overlap area between a head surface and a side surface of a flange portion is substantially half of an area of a head surface. In the detection device according to claim 4 or 5,
A tool holder inclination detecting device in a machine tool, wherein the flange portion is constituted by a disc detachably attached to a tool holder.

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