Dimension measurement device, cutting tool system, and dimension measurement method

Abstract

To provide a dimension measurement device which can efficiently perform dimension measurement of a work material in one direction with high accuracy, and to provide a cutting tool system and a dimension measurement method.SOLUTION: A dimension measurement device includes a sensor unit and a measurement device body. The sensor unit includes: a first distance sensor using an eddy-current sensor; and a signal conversion unit which outputs output signals of the distance sensor as detection values at a preset time interval. The measurement device body includes: a detection control unit which detects a distance to a work material with the sensor unit while rotating the work material; an acquisition unit which acquires the multiple detection values output from the sensor unit at the time interval in a preset specified time period; a calculation unit which calculates an average value of the detection values acquired by the acquisition unit; and a result output unit which outputs a measurement result of the work material based on the average value of the detection values calculated by the calculation unit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a dimension measuring device, a cutting tool system, and a dimension measuring method.

Background Art

[0002] In recent years, the development of tools for cutting processes with various functions has been underway. Patent Document 1 discloses a cutting tool equipped with a distance sensor. By having a distance sensor in the cutting tool, it is possible to measure the dimensions of the workpiece immediately after machining, shortening the time required for measurement and enabling efficient production.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the cutting tool as described above, an eddy current sensor is used as the distance sensor. When measuring the dimensions of the workpiece using an eddy current sensor, a measurement error may occur due to a phenomenon called Electrical Runout. The Electrical Runout phenomenon is considered to be caused by the residual magnetism of the steel material forming the workpiece, non-uniformity of the crystal structure, etc. Due to this Electrical Runout phenomenon, when measuring the diameter dimension of the workpiece after machining, the diameter dimension measured by the eddy current sensor may vary depending on the circumferential position around the central axis of the workpiece.

[0005] On the other hand, it is conceivable to measure the diameter dimension of the workpiece by measuring the diameter dimension of the workpiece with an eddy current sensor at a plurality of positions in the circumferential direction of the workpiece and calculating the average of the measurement values at the plurality of positions. However, it takes time and effort to measure the diameter dimension of the workpiece at a plurality of positions in the circumferential direction of the workpiece. For this reason, it is desired to efficiently and accurately measure the dimensional measurement in the radial direction of the workpiece.

[0006] In view of the above circumstances, one object of the present invention is to provide a dimensional measurement device, a cutting tool system, and a dimensional measurement method capable of efficiently and accurately measuring the dimensions of a workpiece.

Means for Solving the Problems

[0007] One aspect of the dimensional measurement device of the present invention is a dimensional measurement device that measures the dimension of a workpiece in one direction that is rotationally and relatively cut with respect to a cutting tool about a central axis, and a distance to the machined surface of the workpiece in the one direction of the workpiece. A sensor unit that detects the distance, and a measurement device main body that measures the dimension of the workpiece in the one direction based on the distance detected by the sensor unit, and the sensor unit uses an eddy current sensor. A distance sensor, and a signal conversion unit that outputs a detection value based on the output signal of the distance sensor at preset time intervals, and the measurement device main body rotates the workpiece around the central axis of the workpiece while the sensor unit detects the distance to the workpiece. A detection control unit, an acquisition unit that acquires a plurality of the detection values output from the sensor unit at each of the time intervals within a preset specified time, and a calculation unit that calculates an average value of the plurality of detection values acquired by the acquisition unit. And a result output unit that outputs a measurement result of the workpiece based on the average value of the detection values calculated by the calculation unit.

[0008] According to one aspect of the dimensional measurement device of the present invention, while rotating the workpiece to be machined, the distance to the workpiece to be machined is detected by a distance sensor using an eddy current sensor. The sensor unit outputs the output signal of the distance sensor as a detection value at preset time intervals. The measurement device main body calculates the average value of a plurality of detection values output from the sensor unit at time intervals within a preset specified time, and obtains the measurement result of the workpiece to be machined based on the calculated average value of the detection values. In this way, while rotating the workpiece to be machined, a plurality of averaged detection values are acquired from the sensor unit, and further the average value of the plurality of acquired detection values is obtained, thereby suppressing the influence of the electrical runout phenomenon and efficiently performing the dimensional measurement of the workpiece to be machined in one direction. As a result, the dimensional measurement of the workpiece to be machined in one direction can be efficiently and accurately performed while rotating the workpiece to be machined.

[0009] In the above dimensional measurement device, the signal conversion unit may output the average value of the output signal of the distance sensor within the time interval as a detection value at preset time intervals.

[0010] In this case, by using a signal converter that outputs the average value of the output signal as a detection value, the analog output of the distance sensor can be averaged with higher accuracy. In addition, in the description of the following embodiments, the case of using this type of signal converter will be described.

[0011] In the above dimensional measurement device, the detection control unit may rotate the workpiece to be machined at a predetermined rotational speed of 150 min -1 or more and 1500 min -1 or less.

[0012] In this case, by rotating the workpiece to be machined at a predetermined rotational speed of 150 min -1 or more and 1500 min -1 or less and performing the dimensional measurement of the workpiece to be machined in one direction, the number of detection values to be averaged can be increased in a short time. Therefore, the dimensional measurement of the workpiece to be machined in one direction can be performed more efficiently and with higher accuracy.

[0013] In the above-described dimensional measurement device, the acquisition unit may acquire the detection value while rotating the workpiece to be machined five or more times within the specified time.

[0014] In this case, since the detection value is acquired while rotating the workpiece to be machined five or more times within the specified time, the number of detection values to be averaged can be increased. As a result, the dimensional measurement in one direction of the workpiece to be machined can be performed with higher accuracy.

[0015] One aspect of the cutting tool system of the present invention includes the cutting tool including a tool body having a pedestal at a tip portion extending along a tool axis and a cutting insert detachably attached to the pedestal, and the above-described dimensional measurement device.

[0016] According to one aspect of the cutting tool system of the present invention, while rotating the workpiece to be machined by the dimensional measurement device, a plurality of averaged detection values are acquired from the sensor unit, and further, by obtaining the average value of the plurality of acquired detection values, it is possible to efficiently perform the dimensional measurement in one direction of the workpiece to be machined by the cutting tool while suppressing the influence of the electrical runout phenomenon. As a result, the dimensional measurement in one direction of the workpiece to be machined can be efficiently and accurately performed while rotating the workpiece to be machined.

[0017] In the above-described cutting tool system, the sensor unit may be attached to the cutting tool.

[0018] In this case, since the sensor unit is attached to the cutting tool, the dimensional measurement in one direction of the workpiece to be machined by the cutting tool can be efficiently performed by the sensor unit attached to the cutting tool.

[0019] One aspect of the dimensional measurement method of the present invention is a dimensional measurement method for measuring the dimension of a workpiece machined by cutting while rotating relative to a cutting tool about a central axis, comprising: rotating the workpiece about the central axis, detecting the distance to the workpiece with a distance sensor using an eddy current sensor, and outputting, as a detection value, the average value of the outputs of the distance sensor within the time interval for each preset time interval; acquiring a plurality of the detection values output for each time interval within a preset specified time; calculating the average value of the plurality of acquired detection values; and outputting a measurement result of the workpiece based on the average value of the calculated detection values.

[0020] According to one aspect of the dimensional measurement method of the present invention, while rotating the workpiece, a plurality of detection values, which are the average values of the outputs of the distance sensor, are acquired, and further, by obtaining the average value of the plurality of acquired detection values, it is possible to efficiently perform the dimensional measurement of the workpiece in one direction while suppressing the influence of the electrical runout phenomenon. As a result, the dimensional measurement of the workpiece in one direction can be efficiently and highly accurately performed while rotating the workpiece.

Effect of the Invention

[0021] According to the dimensional measurement device, cutting tool system, and dimensional measurement method of one aspect of the present invention, the dimensional measurement of the workpiece in one direction can be efficiently and highly accurately performed.

Brief Description of the Drawings

[0022]

Figure 1

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Figure 9

DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, with reference to the drawings, the turning tool (cutting tool) 1 according to the embodiment of the present invention will be described. In the following drawings, in order to make each configuration easy to understand, the actual structure and the scale, number, etc. in each structure may be made different.

[0024] <Turning Tool System> FIG. 1 is a diagram showing a turning tool system (cutting tool system) 10 according to an embodiment of the present invention. As shown in FIG. 1, the turning tool system 10 includes a turning tool 1 and a measuring device main body 100.

[0025] The turning tool 1 of the present embodiment performs turning processing such as boring on a work material such as a metal material that is rotated around the main shaft of a machine tool (not shown). The turning tool 1 of the embodiment is made of metal and includes a tool body 2, a cutting insert 4, and a head unit 7.

[0026] The tool body 2 extends in the axial direction Dj along the tool axis J. The tool body 2 has a columnar shank portion 21 centered on the tool axis J and a head portion 22 provided on one side Dj1 in the axial direction Dj of the tool body 2 with respect to the shank portion 21.

[0027] The head portion 22 has a protruding portion 23 that protrudes outward in the radial direction Dr of the tool body 2 that intersects the axial direction Dj from the outer peripheral surface of the shank portion 21. A pedestal 23d is provided on the protruding portion 23. A cartridge 41 is attached to the pedestal 23d. The cartridge 41 holds the cutting insert 4. The pedestal 23d and the cutting insert 4 attached to the cartridge 41 are arranged on the first side Dr1 in the radial direction Dr with respect to the tool axis J in the tool body 2. Note that the cutting insert 4 may be directly attached to the pedestal 23d.

[0028] The cutting insert 4 has a rhomboid shape when viewed from the thickness direction. The cutting insert 4 has a pair of main surfaces with a rhomboid shape in plan view facing the thickness direction and side surfaces connecting the pair of main surfaces. A cutting edge 42 is provided on the ridge line between the main surface and the side surface of the cutting insert 4. The cutting edge 42 is provided at the tip of one side Dj1 in the axial direction Dj of the tool body 2. A part of the cutting edge 42 protrudes from the tool body 2 to one side Dj1 in the axial direction Dj. Also, the cutting edge 42 protrudes outward in the radial direction Dr of the tool body 2. Therefore, a part of the cutting edge 42 is located at the outermost tip of one side Dj1 in the axial direction Dj and the outermost end in the radial direction Dr of the tool body 2.

[0029] According to the present embodiment, the cutting insert 4 is fixed to the tool body 2 via the cartridge 41. For this reason, by replacing the cartridge 41, cutting inserts 4 of various shapes can be fixed to the tool body 2, and the versatility of the tool body 2 is enhanced.

[0030] The head unit 7 is provided in the head portion 22. The head unit 7 includes a holder member 70, a sensor unit 3, an imaging device 5, and an illumination device 6. The head unit 7 is disposed on the second side Dr2 in the radial direction Dr with respect to the tool axis J in the tool body 2. That is, the head unit 7 is disposed on the opposite side of the pedestal 23d and the cutting insert 4 attached to the pedestal 23d across the tool axis J in the radial direction Dr of the tool body 2. The holder member 70 is detachably attached to the tool body 2.

[0031] The sensor unit 3 includes a first distance sensor 31 and a second distance sensor 32. The first distance sensor 31 and the second distance sensor 32 are held by the holder member 70. The holder member 70 is attached to the head portion 22. In this embodiment, the first distance sensor 31 and the second distance sensor 32 measure the distance to the machined surface machined using the cutting insert 4. The sensor unit 3 and the measuring device main body 100 together constitute a dimensional measuring device M.

[0032] The first distance sensor 31 is disposed facing outward in the radial direction Dr from the outer peripheral surface of the tool body 2. The first distance sensor 31 measures the distance to the measurement object disposed outside in the radial direction Dr of the tool body 2. That is, the first distance sensor 31 uses the radial direction Dr as the measurement direction. The first distance sensor 31 measures the distance to the machined surface facing the inner side in the radial direction Dr machined by the cutting insert 4.

[0033] The second distance sensor 32 is disposed facing one side Dj1 in the axial direction Dj from the head portion 22 of the tool body 2. The second distance sensor 32 measures the distance to the measurement object disposed on one side Dj1 in the axial direction Dj of the tool body 2. That is, the second distance sensor 32 uses the axial direction Dj as the measurement direction. The second distance sensor 32 measures the distance to the machined surface facing the other side Dj2 in the axial direction Dj machined by the cutting insert 4.

[0034] The first distance sensor 31 and the second distance sensor 32 are eddy current sensors. Eddy current sensors are less likely to be affected by external disturbances such as the surrounding environment, and thus are more suitable for distance measurement in an environment with many disturbances after cutting compared to optical distance sensors, regardless of whether wet machining or dry machining is selected. The first distance sensor 31 and the second distance sensor 32 generate a high-frequency magnetic field by passing a high-frequency current through their interiors. As a result, eddy currents flow on the surface (machined surface) of the measurement object, which is a conductor, and the impedance of the coils inside the first distance sensor 31 and the second distance sensor 32 changes. The first distance sensor 31 and the second distance sensor 32 detect the distance to the measurement object from this change in impedance. The first distance sensor 31 and the second distance sensor 32 output, as their respective output values, a voltage (unit: V) indicating the change in impedance.

[0035] The first distance sensor 31 and the second distance sensor 32 are used to measure the machined surface after the turning tool 1 has formed the machined surface. Since the first distance sensor 31 and the second distance sensor 32 are provided on the tool body 2, the machined surface after cutting can be measured without temporarily separating the turning tool 1 from the workpiece, which can shorten the time required for measuring the machined surface in turning. Also, using the first distance sensor 31, the distance to the machined surface facing the inside in the radial direction Dr machined by the cutting insert 4 can be measured, and using the second distance sensor 32, the distance to the machined surface facing the other side Dj2 in the axial direction Dj machined by the cutting insert 4 can be measured. That is, during dimensional measurement, dimensional measurement of surfaces facing different directions can be performed without changing the orientation of the workpiece, further shortening the time required for the measurement process. Note that the outer diameter, inner diameter, roundness, etc. machined by the cutting insert 4 can be measured by the first distance sensor 31. Also, the axial position of the stepped portion and the bottom of the hole machined by the cutting insert 4 can be measured by the second distance sensor 32.

[0036] The imaging device 5 is provided in the head unit 7 of the tool body 2. The imaging device 5 is arranged on the other side Dj2 in the axial direction Dj with respect to the sensor unit 3. The imaging device 5 includes a camera 51. The camera 51 is, for example, a waterproof CMOS image sensor or a CCD image sensor. The camera 51 is fixed to the holder member 70. The camera 51 is arranged so as to be able to photograph the outside in the radial direction Dr of the tool body 2. The camera 51 photographs the machining surface facing the inside in the radial direction Dr of the workpiece machined by the cutting insert 4, that is, the so-called inner diameter surface.

[0037] The lighting device 6 is provided in the head unit 7 of the tool body 2. The lighting device 6 is arranged on the other side Dj2 in the axial direction Dj with respect to the camera 51 of the imaging device 5. The lighting device 6 includes a light source 61 that illuminates the machining surface photographed by the camera 51. The light source 61 is a light-emitting element such as an LED, for example.

[0038] The turning tool 1 includes a tool control unit 81, a communication unit 82, and a power module 83. In the present embodiment, the tool control unit 81 is, in terms of hardware, for example, a control board housed inside the tool body 2. The tool control unit 81 is a computer including a CPU (Central Processing Unit), a memory, and the like. A control program for controlling the operations of the first distance sensor 31, the second distance sensor 32, the camera 51, and the light source 61 is stored in advance in the memory (not shown) of the tool control unit 81.

[0039] Based on a command from the measurement device main body 100 described later, the tool control unit 81 outputs control signals for controlling the operations of the first distance sensor 31, the second distance sensor 32, the camera 51, and the light source 61 to the first distance sensor 31, the second distance sensor 32, the camera 51, and the light source 61.

[0040] The tool control unit 81 includes signal conversion units 35A and 35B that convert an analog output signal indicating a voltage value output according to the detection results (distances) of the first distance sensor 31 and the second distance sensor 32 into a digital signal. The signal conversion units 35A and 35B are composed of converters. The signal conversion unit 35A outputs, as a detection value, the average value of the output signals from the first distance sensor 31 within a preset time interval (sampling interval) at each preset time interval. The signal conversion unit 35B outputs, as a detection value, the average value of the output signals from the second distance sensor 32 within a preset time interval at each preset time interval.

[0041] The communication unit 82 can perform wireless communication with the outside. Hardware-wise, the communication unit 82 is a communication module mounted on the control board that constitutes the tool control unit 81. The communication unit 82 can perform wireless communication with the measurement device main body 100 via a wireless communication network such as a wireless LAN, Wi-Fi (registered trademark), or BLUETOOTH (registered trademark). The communication unit 82 receives control signals for controlling the operations of the first distance sensor 31, the second distance sensor 32, the camera 51, and the light source 61 output from the measurement device main body 100. The communication unit 82 transmits the detection values from the signal conversion units 35A and 35B, image data captured by the camera 51, etc. to the measurement device main body 100. The communication unit 82 transmits the remaining amount (battery voltage) of the power module 83 to the measurement device main body 100.

[0042] The power module 83 supplies power to the tool control unit 81, the first distance sensor 31, the second distance sensor 32, the camera 51, and the light source 61. The power module 83 is, for example, a primary battery (battery) such as a manganese dry battery or an alkaline dry battery. Also, the power module 83 may be one that charges a secondary battery such as a lithium-ion battery with electricity from a power generation element such as a piezo vibration sensor that generates electricity by the vibration generated in the tool body 2 during cutting, or may be one that charges such a secondary battery with electricity supplied in a contact or non-contact manner from an external power source.

[0043] <Measurement device main body> FIG. 2 is a functional block diagram of the measuring device main body 100. The measuring device main body 100 that constitutes part of the measuring device M is, for example, a computer device such as a personal computer, a tablet terminal, or a smartphone. The measuring device main body 100 is hardware-wise equipped with a CPU (Central Processing Unit), a memory, a storage device, etc. The measuring device main body 100 is used when machining a workpiece with a turning tool 1. The measuring device main body 100 in the present embodiment measures the diameter dimension of a workpiece that has been cut by rotating relative to the turning tool 1 about the central axis O.

[0044] When machining a workpiece with the turning tool 1 based on a machining program stored in the machine tool, the measuring device main body 100 controls the operations of the first distance sensor 31, the second distance sensor 32, the camera 51, and the light source 61 of the turning tool 1 based on a command from the machine tool. The measuring device main body 100 performs dimensional measurement of the workpiece using the first distance sensor 31 and the second distance sensor 32, and photographing of the machined surface using the camera 51 based on a command from the machine tool. In the following description of the measuring device main body 100, the description will focus on the dimensional measurement in the radial direction of the workpiece using the first distance sensor 31, and the description of the dimensional measurement in the axial direction of the workpiece using the second distance sensor 32 and the photographing of the machined surface using the camera 51 will be omitted as appropriate.

[0045] The measuring device main body 100 includes a detection control unit 101, an acquisition unit 103, a calculation unit 105, and a result output unit 107 by the CPU executing a program stored in the device in advance. After the machining of the workpiece by the tool body 2 is completed, when measuring the dimensions of the machined workpiece, the detection control unit 101 controls the operations of the machine tool (not shown) and the turning tool 1. When measuring the dimensions of the workpiece, the detection control unit 101 rotates the workpiece held by the machine tool around the central axis O of the workpiece. The detection control unit 101 causes the sensor unit 3 to detect the distance to the workpiece while rotating the workpiece around the central axis O of the workpiece.

[0046] In this embodiment, the detection control unit 101 rotates the workpiece at a predetermined rotational speed of, for example, 150 min -1 or more and 1500 min -1 or less. When measuring the dimensions of the workpiece, the rotational speed at which the workpiece is rotated is preferably 250 min -1 or more and 1200 min -1 or less. When measuring the dimensions of the workpiece, the rotational speed at which the workpiece is rotated is particularly preferably 300 min -1 or more and 600 min -1 or less. When measuring the dimensions of the workpiece, while rotating the workpiece at a rotational speed within the above range, the first distance sensor 31 detects the distance to the machined surface of the workpiece, thereby suppressing the influence of the electrical runout phenomenon of the workpiece. When measuring the dimensions of the workpiece, if the workpiece is rotated at a rotational speed lower than the lower limit rotational speed of the above range, the influence of the electrical runout phenomenon of the workpiece may not be sufficiently suppressed. Also, when measuring the dimensions of the workpiece, if the workpiece is rotated at a rotational speed equal to or higher than the upper limit rotational speed of the above range, the mechanical vibration of the machine tool may increase, which may adversely affect the dimension measurement of the workpiece.

[0047] The acquisition unit 103 can communicate wirelessly with the communication unit 82 via a wireless LAN, Wi-Fi (registered trademark), BLUETOOTH (registered trademark), or the like. The acquisition unit 103 acquires the detection values output from the signal conversion units 35A and 35B of the sensor unit 3. The acquisition unit 103 acquires the detection values output from the sensor unit 3 within a preset specified time. In the first distance sensor 31 and the second distance sensor 32 of the sensor unit 3, a voltage (analog output signal) corresponding to the detection result (distance) of the distance to the processed surface of the workpiece is output. The analog output signals output from each of the first distance sensor 31 and the second distance sensor 32 are converted into digital signals by the signal conversion units 35A and 35B. The signal conversion units 35A and 35B output the digital signals obtained by converting the analog output signals output from each of the first distance sensor 31 and the second distance sensor 32 at preset time intervals. The signal conversion units 35A and 35B output, as detection values, the average values of the analog output signals from each of the first distance sensor 31 and the second distance sensor 32 within the preset time intervals at the preset time intervals. That is, the acquisition unit 103 acquires, as detection values, the average values of the analog output signals from each of the first distance sensor 31 and the second distance sensor 32 of the sensor unit 3 within a preset time interval. Here, the time interval can be set to, for example, 0.125 seconds or the like.

[0048] The acquisition unit 103 acquires the detection values output from the signal conversion unit 35A of the sensor unit 3, for example, during a specified time set so that the workpiece rotated around the central axis O by a machine tool has a rotational speed of, for example, 5 or more and 50 or less rotations. The specified time for the acquisition unit 103 to acquire the detection values output from the sensor unit 3 is the rotational speed of the workpiece (rotational speed [min -1) varies. It is more preferable that the acquisition unit 103 acquires the detection value output from the signal conversion unit 35A for a specified time period during which the workpiece is set to have a rotational speed of, for example, 10 revolutions or more and 20 revolutions or less. If the rotational speed of the workpiece is less than the lower limit value of the above range, the number of detection values from the sensor unit 3 that can be acquired by the acquisition unit 103 decreases, and the influence of the electrical run-out phenomenon may not be sufficiently suppressed. Also, if the rotational speed of the workpiece is more than the upper limit value of the above range, the time required for the acquisition unit 103 to detect a plurality of detection values becomes longer.

[0049] The calculation unit 105 calculates the average value of the plurality of detection values acquired by the acquisition unit 103. The calculation unit 105 calculates the average value of the plurality of detection values acquired by the acquisition unit 103 during a specified time period.

[0050] The result output unit 107 outputs the measurement result of the workpiece based on the average value of the detection values calculated by the calculation unit 105. The result output unit 107 calculates the dimension in the radial direction of the workpiece from the calculated distance to the machined surface of the workpiece. The result output unit 107 displays information regarding the calculated dimension measurement result of the workpiece on a display device such as a monitor. The result output unit 107 may perform a determination on the quality of machining in the machine tool based on the dimension measurement result of the workpiece and display the determination result and the like.

[0051] <Dimension Measurement Method> Next, a dimension measurement method in the turning tool system 10 as described above will be explained. FIG. 3 is a flowchart showing the flow of the dimension measurement method according to an embodiment of the present invention. As shown in FIG. 3, the dimension measurement method in the turning tool system 10 includes a machining process S1, a distance detection process S2, a detection value acquisition process S3, an average value calculation process S4, and a measurement result output process S5.

[0052] FIGS. 4A and 4B are diagrams showing a machining process according to an embodiment of the present invention. As shown in FIGS. 4A and 4B, the workpiece W of the present embodiment has a through-hole 200 with a step. The through-hole 200 has a stepped surface 203, a large-diameter portion 201 on one axial side with respect to the stepped surface 203, and a small-diameter portion 202 on the other axial side with respect to the stepped surface 203. In the present embodiment, the turning tool 1 is used to finish the large-diameter portion 201 and the stepped surface 203 of the through-hole 200 (so-called inner diameter machining).

[0053] In the machining step S1, as shown in FIG. 4A, the inner peripheral surface of the large-diameter portion 201 is machined. In this step, while rotating the workpiece W around the spindle O, the cutting edge 42 is brought into contact with the inner peripheral surface of the large-diameter portion 201 of the workpiece W and moved in the axial direction. Further, in the machining step S1, as shown in FIG. 4B, the stepped surface 203 is machined. In this step, while continuously rotating the workpiece W around the spindle O, the cutting edge 42 is moved in the radial direction to machine the stepped surface 203.

[0054] After the machining step S1, a distance detection step S2 is performed. In the distance detection step S2, detection values corresponding to the respective distances from the workpiece W are acquired using the first distance sensor 31.

[0055] FIG. 5 shows a state in which the first distance sensor 31 is performing distance detection in the radial direction of the workpiece in the distance detection step S2. In the distance detection step S2, first, the tip surface 31a of the first distance sensor 31 is opposed to the inner peripheral surface (machined surface) of the large-diameter portion 201. Next, the workpiece held by the machine tool is rotated around the central axis (spindle) O of the workpiece. In the detection control unit 101, while rotating the workpiece W around the central axis O of the workpiece W, the first distance sensor 31 detects the distance to the inner peripheral surface of the large-diameter portion 201 of the workpiece W. At this time, the detection control unit 101 rotates the workpiece at a predetermined rotational speed of, for example, 150 min -1 1500 min or more -1 and below.

[0056] From the first distance sensor 31, an analog output signal (voltage value) corresponding to the distance to the inner peripheral surface of the large-diameter portion 201 of the workpiece W is output. The analog output signal output from the first distance sensor 31 is converted into a digital signal by the signal conversion unit 35A. In the signal conversion unit 35A, the average value of the analog output signals from the first distance sensor 31 within that time interval is output as a detection value at preset time intervals.

[0057] After the distance detection step S2, a detection value acquisition step S3 is performed. In the detection value acquisition step S3, the acquisition unit 103 acquires the detection value output from the signal conversion unit 35A. The acquisition unit 103 acquires a plurality of the detection values output at each time interval within a preset specified time. The acquisition unit 103 acquires the detection value output from the signal conversion unit 35A, for example, during a specified time set so that the workpiece W rotates, for example, 10 times.

[0058] After the detection value acquisition step S3, an average value calculation step S4 is performed. In the average value calculation step S4, the calculation unit 105 calculates the average value of the plurality of detection values acquired in step S3. The calculation unit 105 calculates the average value of the radial distances from the first distance sensor 31 to the machined surface of the workpiece W at a plurality of locations around the central axis O of the workpiece W.

[0059] After the average value calculation step S4, a measurement result output step S5 is performed. In the measurement result output step S5, the result output unit 107 outputs the measurement result of the workpiece W based on the average value of the detection values calculated in step S4. The result output unit 107 calculates the radial dimension of the workpiece W from the calculated distance to the machined surface of the workpiece W. The result output unit 107 may display information regarding the calculated dimensional measurement result of the workpiece on a display device such as a monitor.

[0060] Note that the above steps S2 to S5 may be performed in the same manner at a plurality of positions having the same inner diameter of the workpiece W by moving the first distance sensor 31 in the direction of the central axis O of the workpiece W with respect to the workpiece W.

[0061] 〔Advantages and effects of this embodiment〕 According to the dimensional measurement device M, the turning tool system 10, and the dimensional measurement method of this embodiment described above, while rotating the workpiece, a plurality of detection values that are the average values of the outputs of the first first distance sensor 3131 are acquired, and further, by obtaining the average value of the plurality of acquired detection values, it is possible to efficiently perform dimensional measurement in the radial direction of the workpiece while suppressing the influence of the electrical runout phenomenon. As a result, dimensional measurement in the radial direction of the workpiece can be efficiently performed with high accuracy while rotating the workpiece.

[0062] Also, in this embodiment, the workpiece is rotated at a predetermined rotational speed of 150 min -1 or more and 1500 min -1 or less, and dimensional measurement in the radial direction of the workpiece is performed. Thereby, the number of detection values to be averaged can be increased in a short time. Therefore, dimensional measurement in the radial direction of the workpiece can be performed more efficiently and with high accuracy.

[0063] Also, in this embodiment, detection values are acquired while rotating the workpiece five or more times within a specified time. Thereby, the number of detection values to be averaged can be increased. Thereby, dimensional measurement in the radial direction of the workpiece can be performed with higher accuracy.

[0064] Also, in this embodiment, the sensor unit 3 is attached to the turning tool 1. Thereby, dimensional measurement in the radial direction of the workpiece machined by the turning tool 1 can be efficiently performed by the sensor unit 3 attached to the turning tool 1.

[0065] In addition, in the present embodiment, the case where the dimension measuring device M, the direction of machining the workpiece by the turning tool system, and the direction of dimension measurement are in the radial direction of the central axis O has been illustrated. However, the direction of machining the workpiece by the dimension measuring device M and the turning tool system, and the direction of dimension measurement may be in the axial direction of the central axis O. In this case, the turning tool 1 cuts the end face facing the axial direction of the workpiece W that rotates around the central axis O. Further, the sensor unit 3 detects the distance from the end face facing the axial direction of the workpiece W.

[0066] In the present embodiment, the case where the signal conversion unit 35A outputs the average value of the output signals of the first distance sensor 31 within the time interval as the detection value at each preset time interval has been described. However, the output signal of the first distance sensor 31 may be output as the detection value without being averaged. That is, the signal conversion unit 35A may output the detection value based on the output signal of the first distance sensor 31. In this case, in the calculation unit 105, a dimension measuring device that obtains the same operational effects by averaging the detection values can be configured. Also, even in this case, the signal conversion unit 35A outputs the detection value at each preset time interval. Here, the time interval at which the signal conversion unit 35A outputs the detection value is the sampling period of the converter of the signal conversion unit 35A. That is, the signal conversion unit 35A outputs the output signal of the distance sensor as the detection value as it is, or outputs the detection value after averaging the output signal, at each sampling period of the converter.

[0067] (Modification of the embodiment) In addition, in the above embodiment, when performing dimension measurement in the radial direction of the workpiece by the dimension measuring device M, calibration according to the material of the workpiece etc. may be performed. In this case, in advance, grasp the distance detection error in the first distance sensor 31 due to the influence of the material of the workpiece etc. by experiments etc., and based on the grasped result, the distance detection result in the first distance sensor 31 may be calibrated. In the above-described embodiment, the sensor unit 3 is attached to the turning tool 1, but the present invention is not limited to this. The sensor unit 3 may be provided independently separately from the turning tool 1. In this case, the sensor unit 3 may be provided, for example, on the machine tool side.

[0068] Other configurations included in the present invention Note that the present invention is not limited to the above-described embodiments, and within the scope not departing from the gist of the present invention, the above-described embodiments, modification examples, and each configuration (component) described in the amendments and the like may be combined, and addition, omission, substitution, and other changes of the configuration are possible. Further, the present invention is not limited by the above-described embodiments, but is limited only by the scope of the claims.

[0069] For example, in the above-described embodiment, the case where a turning tool that rotates the workpiece to perform cutting is adopted as an example of the cutting tool included in the cutting tool system has been described. However, the turning tool is not limited to the turning tool of the present embodiment as long as it presses the cutting insert against the workpiece to perform cutting. The cutting tool may be, for example, a rotary tool that rotates itself, such as a drill, an end mill, or a milling machine.

[0070] (Example) Verification was performed on the configuration as shown in the above-described embodiment, and the results are shown below. First, the occurrence of the electrical runout phenomenon was confirmed. For this, after machining the workpiece, the inner diameter dimension was measured with a dial gauge, and it was confirmed in advance that the variation in the diameter dimension (mechanical runout) at a plurality of positions in the circumferential direction was within 0.5 μm. Thereafter, the workpiece was rotated by 5° around the central axis O, and at each phase, the distance to the inner peripheral surface of the large-diameter portion 201 of the workpiece was detected by the first distance sensor 31. At this time, when the distance was detected by the first distance sensor 31, the workpiece was fixed at each phase without being rotated.

[0071] Figure 6 shows the variation in the detection distance to the machined surface of the workpiece in the radial direction due to the electrical runout phenomenon. As a result, it was confirmed that the detected distance varied depending on the phase of the workpiece, with a difference of 8 μm between the minimum and maximum values, as shown in Fig. 6. Since the variation is larger than the measurement results using a dial gauge, it can be inferred that this is due to the electrical runout phenomenon.

[0072] Next, the workpiece was rotated around the central axis O by the machine tool, and the distance to the inner circumferential surface of the large diameter portion 201 of the workpiece was detected by the first distance sensor 31. -1 , 300min -1 , 600min -1 , 1200min -1 The rotor was rotated at four different rotation speeds, and distance detection was performed by the first distance sensor 31 at time intervals of 0.125 seconds.

[0073] FIG. 7 is a diagram showing variation in the detected distance to the machined surface of the workpiece in the radial direction when the rotation speed of the workpiece is changed. As a result, as shown in Figure 7, -1 When the workpiece was rotated at a rotation speed of 300 min, the detected distance varied. -1 , 600min -1 , 1200min -1 It was confirmed that when the workpiece was rotated at a rotational speed of 1000 rpm, the variation in detection distance was equivalent to the measurement results using a dial gauge.

[0074] Next, the workpiece is rotated around the central axis O by the machine tool for 300 min. -1While rotating, the rotational speed of the workpiece was set to three levels: 2.5 revolutions, 5 revolutions, and 10 revolutions when detecting the distance to the inner peripheral surface of the workpiece with the first distance sensor 31. Then, the average value of the detection values output from the signal conversion unit 35A was calculated until the rotational speed of the workpiece reached each of 2.5 revolutions, 5 revolutions, and 10 revolutions. Furthermore, for each of the rotational speeds of 2.5 revolutions, 5 revolutions, and 10 revolutions, the same distance detection and calculation of the average value of the detection values were repeated 10 times. FIG. 8 is a diagram showing the average value of the detection values to the machined surface of the workpiece in the radial direction when the rotational speed of the workpiece is varied. As a result, as shown in FIG. 8, it was confirmed that the greater the rotational speed of the workpiece when detecting the distance to the inner peripheral surface of the workpiece with the first distance sensor 31, the smaller the variation in the average value of the detection values.

[0075] Furthermore, the workpiece was rotated at four rotational speeds of 60 min -1 , 300 min -1 , 600 min -1 , 1200 min -1 around the central axis O by a machine tool, and the distance detection and calculation of the average value of the detection values were repeated in the same manner as above. FIG. 9 is a diagram showing the variation (maximum - minimum) of the average value of the detection values for 10 repetitions of the average value of the detection values to the machined surface of the workpiece in the radial direction when the dimensional measurement in the radial direction of the workpiece is repeated. As a result, as shown in FIG. 9, when the rotational speed of the workpiece is 300 min -1 , 600 min -1 , 1200 min -1 , it was confirmed that when the rotational speed of the workpiece is 5 revolutions or more when detecting the distance to the inner peripheral surface of the workpiece with the first distance sensor 31, the variation in the detection values becomes small. In contrast, when the rotational speed of the workpiece is 60 min -1 , compared with the cases of 300 min -1 , 600 min -1 , 1200 min -1 , even if the rotational speed of the workpiece increases, the variation in the detection values is large.

[0076] Within the scope not departing from the gist of the present invention, the respective configurations described in the above-described embodiments, modifications, and the like may be combined, and addition, omission, substitution, and other changes of the configurations are possible. Further, the present invention is not limited by the above-described embodiments and the like, and is limited only by the scope of the claims.

Explanation of Reference Numerals

[0077] 1…Turning tool (cutting tool) 2…Tool body 3…Sensor unit 4…Cutting insert 5…Imaging device 6…Illumination device 7…Head unit 10…Turning tool system (cutting tool system) 21…Shank portion 22…Head portion 23…Protrusion 23d…Pedestal 31…First distance sensor 31a…Tip surface 32…Second distance sensor 35A, 35B…Signal conversion unit 41…Cartridge 42…Cutting edge 51…Camera 61…Light source 70…Holder member 81…Tool control unit 82…Communication unit 83…Power module 100…Measurement device body 101…Detection control unit 103…Acquisition unit 105…Calculation unit 107…Result output unit 200…Through hole 201…Large diameter portion 202…Small diameter portion 203…Step surface Dj…Axial direction Dj1…One side Dj2…The other side Dr…Radial direction Dr1…First side Dr2... Second side J... Tool axis M... Dimension measuring device O... Central axis, main axis S1... Machining process S2... Distance detection process S3... Detection value acquisition process S4... Average value calculation process S5... Measurement result output process W... Workpiece

Claims

1. A dimensional measurement device for measuring the dimension of a workpiece in one direction that is rotationally machined relative to a cutting tool about a central axis, comprising: a sensor unit that detects the distance to the machined surface of the workpiece in the one direction of the workpiece; a measurement device body that measures the dimension of the workpiece in the one direction based on the distance detected by the sensor unit. The sensor unit includes a distance sensor using an eddy current sensor, and a signal conversion unit that outputs a detection value based on the output signal of the distance sensor at preset time intervals. The measurement device body includes a detection control unit that causes the sensor unit to detect the distance to the workpiece while rotating the workpiece about the central axis, an acquisition unit that acquires a plurality of the detection values output from the sensor unit at each of the time intervals within a preset specified time, a calculation unit that calculates the average value of the plurality of detection values acquired by the acquisition unit, and a result output unit that outputs the measurement result of the workpiece based on the average value of the detection values calculated by the calculation unit. A dimensional measurement device.

2. The signal conversion unit outputs, as a detection value, the average value of the output signal of the distance sensor within the time interval at each preset time interval. The dimensional measurement device according to claim 1.

3. The detection control unit is configured to detect the workpiece for 150 min. －１ More than 1500min －１ Rotate at the following specified rotation speeds: The dimensional measurement device according to claim 1.

4. The acquisition unit acquires the detection values while rotating the workpiece five or more times within the specified time. The dimensional measurement device according to any one of claims 1 to 3.

5. The cutting tool comprising a tool body extending along a tool axis and having a pedestal at a tip, and a cutting insert detachably attached to the pedestal, and the dimensional measurement device according to any one of claims 1 to 3. A cutting tool system.

6. The sensor unit is attached to the cutting tool. The cutting tool system according to claim 5.

7. A dimensional measurement method for measuring the dimension of a workpiece in one direction that is rotationally machined relative to a cutting tool about a central axis, comprising: while rotating the workpiece about the central axis, detecting the distance to the workpiece with a distance sensor using an eddy current sensor, and outputting, as a detection value, the average value of the output of the distance sensor within the time interval at each preset time interval; acquiring a plurality of the detection values output at each of the time intervals within a preset specified time. A step of calculating an average value of the plurality of obtained detection values; A step of outputting a measurement result of the workpiece to be machined based on the calculated average value of the detection values; and A dimensional measurement method.

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