Measurement aid, cutting temperature measuring device, and cutting temperature measuring method

Abstract

To provide a measurement auxiliary tool which suppresses modification to a processing machine itself, and can easily perform measurement of a cutting temperature during milling by tool-work-piece thermocouple method.SOLUTION: A measurement auxiliary tool 30 comprises: a cylindrical guide pipe 32 on one end side of which a fitting part 41 is formed, in which a guide hole 44 is formed, and which guides a first conductor wire 13a inserted in the guide hole 44 from one end side to the other end side; a rotary connector 34 which has relatively rotatable rotation side terminal 48a and stationery side terminal 49a that are so arranged as to be separated from each other in an axial direction, and in which a rotary part 48 is connected to the other end side of the guide pipe 32 so that the rotation side terminal 48a faces the guide hole 44; and a holding arm 36 for holding the rotary connector 34. The first conductor wire 13a inserted in the guide hole 44 is connected to a non-rotational second conductor wire 13b via the rotation side terminal 48a and the stationery side terminal 49a of the rotary connector 34.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a measuring aid, a cutting temperature measuring device, and a cutting temperature measuring method, and more particularly to a measuring aid, a cutting temperature measuring device, and a cutting temperature measuring method suitable for use in measuring cutting temperatures during milling. [Background technology]

[0002] The cutting temperature during cutting has a significant effect on tool wear, and it is important to understand the cutting temperature in order to understand the cutting phenomenon. One known method for measuring cutting temperatures is the tool-workpiece thermocouple method (see, for example, Patent Document 1 below). In this method, potentials are extracted from both the tip (tool) with the cutting edge and the workpiece, and the cutting temperature is derived from the thermoelectromotive force between the tip and workpiece calculated from the difference between these two potentials. Compared to other measurement methods, this tool-workpiece thermocouple method is an effective method that strikes a good balance between cost and measurement accuracy. However, because it requires a conductor to be drawn from near the tip, there are few examples of it being applied to milling processes in which the tip rotates at high speed around the axis of the spindle.

[0003] For example, as described in Non-Patent Document 1 below, it is possible to provide a rotating contact (mercury contact) on the end of the rotating spindle opposite the tip and extract a signal from the tip through this rotating contact, but this requires modifying the processing machine itself, which increases the cost required for measurement.In addition, the processing machines that can measure temperature are limited, and measurements cannot be performed on other unmodified processing machines, so it lacks versatility. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-202704 [Non-patent literature]

[0005] [Non-Patent Document 1] Mitsuaki Murata, "Study on in-process detection of milling tool wear", URL: https: / / doi.org / 10.15017 / 1398356 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in light of the above circumstances, with the objective of providing a measurement aid, a cutting temperature measuring device, and a cutting temperature measuring method that can easily measure the cutting temperature during milling using the tool-workpiece thermocouple method, without requiring modifications to the processing machine itself. [Means for solving the problem]

[0007] The measurement aid of the first aspect of the present invention is defined as follows: a cylindrical guide tube having an attachment portion formed at one end thereof to be fixed to a mating member and a guide hole formed therein, the guide hole guiding a first conducting wire inserted from the one end thereof into the guide hole to the other end thereof; a rotary connector having a rotating-side terminal and a fixed-side terminal that are arranged axially apart and can rotate freely relative to each other, and a rotating portion connected to the other end of the guide tube so that the rotating-side terminal faces the guide hole; a holding arm for holding the rotary connector; Equipped with The first conducting wire inserted into the guide hole is connected to a non-rotating second conducting wire via the rotating-side terminal and the fixed-side terminal of the rotary connector.

[0008] The measurement auxiliary device of the first aspect defined in this manner allows the conductor drawn out from the opposing member to rotate as the first conductor when the opposing member to which the guide tube is fixed rotates, thereby preventing twisting or breakage of the first conductor and enabling the signal from the opposing member to be stably extracted from the non-rotating second conductor. The measuring aid thus defined is suitable for use in measuring the tip potential during milling. By using this measuring aid, it is possible to easily measure the cutting temperature during milling using the tool-workpiece thermocouple method without having to modify the processing machine itself.

[0009] A cutting temperature measuring device according to a second aspect of the present invention is defined as follows: A cutting temperature measuring device that measures the potential from each of the workpiece and tip during milling and measures the cutting temperature from the thermoelectric power between the tip and workpiece, A measuring aid according to the first aspect of the present invention is provided. the mounting portion of the guide tube is fixed to a tool holder that holds the tip and rotates together with the tip; A signal from the chip is taken out via the first conductor and the second conductor.

[0010] According to the cutting temperature measuring device of the second aspect defined in this way, when the tool holder to which the guide tube is fixed rotates, the conductor drawn out from the tip on the tool holder side is allowed to rotate as the first conductor, thereby preventing twisting or breakage of the first conductor and enabling the signal from the tip to be stably extracted from the non-rotating second conductor. In this case, the modification to the processing machine is limited to the formation of screw holes for attaching auxiliary measuring tools, so that the modification to the processing machine itself can be kept to a minimum and the cutting temperature during milling can be easily measured using the tool-workpiece thermocouple method.

[0011] Here, the rotary connector can be disposed so that the rotation-side terminal is on the rotation axis of the tool holder (third aspect). This makes it possible to suppress vibration of the first conducting wire connected to the rotation-side terminal when it rotates.

[0012] A cutting temperature measuring method according to a fourth aspect of the present invention is defined as follows: This is a method for measuring the cutting temperature from the thermoelectric power between the tip and the workpiece by measuring the potential from each of the workpiece and the tip during milling. Using the measurement aid according to the first aspect, The mounting portion of the guide tube is fixed to a tool holder that holds the tip and rotates together with the tip; A signal from the chip is taken out via the first conductor and the second conductor. The cutting temperature measuring method defined in this way has the same effects as the cutting temperature measuring device of the second aspect. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is an explanatory diagram illustrating cutting temperature measurement using a cutting temperature measuring device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing the measurement aid of FIG. 1 attached to a milling machine. [Figure 3] FIG. 2 is an exploded perspective view of the measurement aid of FIG. 1. [Figure 4] (A) is a diagram showing a chip fixing structure, and (B) is a diagram showing a chip fixing structure different from (A). [Figure 5] FIG. 2 is an enlarged view of the rotary connector and its surrounding area in FIG. 1. [Figure 6] FIG. 2 is a diagram showing an example of a cutting temperature-machining time curve measured using the cutting temperature measuring device. DETAILED DESCRIPTION OF THE INVENTION

[0014] Next, an embodiment of the present invention will be described in detail with reference to the drawings. 1 is an explanatory diagram of cutting temperature measurement using a cutting temperature measuring device according to one embodiment of the present invention, showing the state in which the cutting temperature measuring device is attached to a milling machine. In the figure, reference numeral 1 denotes a milling machine that performs milling, and is equipped with a spindle 5 that extends downward from the center of a spindle base 3 and rotates around an axis P, and a cutting tool 8 attached to the tip (lower end) of the spindle 5.

[0015] The cutting tool 8 includes a tool holder 9 and a tip 12. The tool holder 9 has a plurality of tip mounting seats 10 formed at approximately equal intervals around the periphery of the tip. A tip 12 having a cutting edge made of a hard material such as cemented carbide is removably attached to each tip mounting seat 10. The cutting tool 8 is fixed to the spindle 5 so that its tool axis coincides with the rotation axis (axis P) of the spindle 5, and is rotated by the spindle 5 about axis P.

[0016] Below the cutting tool 8, a metal workpiece W as a workpiece to be milled by the cutting tool 8 is fixed by a fixture 20 with an insulator 21 interposed therebetween.

[0017] Reference numeral 25 denotes a cutting temperature measuring device that measures the cutting temperature during milling using the tool-workpiece thermocouple method, and is equipped with a voltmeter 27 and a measuring aid 30. In the tool-workpiece thermocouple method, potentials are extracted from the tip (tool) 12 and the workpiece (workpiece) W, and the cutting temperature is derived from the thermoelectromotive force between the tip and workpiece calculated from the difference between these two potentials. For this reason, in this example, the lead wire 13 drawn from the tip 12 is connected to the voltmeter 27, and the lead wire 22 drawn from the workpiece W is also connected to the voltmeter 27.

[0018] FIG. 4A is a diagram showing an example of a fixing structure for the chip 12. As shown in FIG. The tip mounting seat 10 formed on the tool holder 9 has a bottom surface 10a serving as a seating surface and side surfaces 10b extending from the bottom surface 10a. In the example shown in FIG. 4A, the bottom surface 10a is provided with an internally threaded hole 11 that threads onto a tip fixing bolt 15. Meanwhile, the side surfaces 10b are restraining surfaces for positioning the tip 12, against which the side surfaces of the tip 12 abut. The tip 12 is formed with a through hole 14 that penetrates the centers of its upper and lower surfaces. In this example, with an insulator 17 disposed on the inner surface of the through hole 14 of the tip 12 and between the tip 12 and the tip mounting seat 10, the tip fixing bolt 15 is screwed into the internally threaded hole 11 of the tip mounting seat 10, thereby fixing the tip 12 to the tip mounting seat 10. At this time, a conductor 13 is inserted between the tip 12 and the tip mounting seat 10, specifically, into the gap between the tip 12 and the insulator 17, thereby connecting the conductor 13 to the tip 12.

[0019] The fixing structure of the chip 12 may be such that the chip 12 is fixed directly by the chip fixing bolt 15 as in the example of Figure 4(A), or, for example, as shown in Figure 4(B), the chip 12 is fixed by the chip fixing bolt 15 via a pressing plate 18. In this case, an insulator 17 is disposed between the chip 12 and the chip mounting seat 10 and between the chip 12 and the pressing plate 18, and a conducting wire 13 is inserted between the chip 12 and the chip mounting seat 10, more specifically, into the gap between the chip 12 and the insulator 17, to connect the conducting wire 13 to the chip 12. In this example, the lead wire 13 connecting the tip 12 and the voltmeter 27 is divided into a rotatable first lead wire 13a and a non-rotatable second lead wire 13b via the measurement aid 30.

[0020] Fig. 2 is a perspective view showing the state in which the measurement aid 30 is attached to the milling machine 1, and Fig. 3 is an exploded perspective view of the measurement aid 30. The measurement aid 30 includes a guide tube 32, a rotary connector 34, and a holding arm 36. The guide tube 32 is a cylindrical member having a flange-shaped mounting portion 41 formed at one end (upper side in the figure) and a large-diameter portion 42 with a larger diameter than the other portion formed at the other end. The guide tube 32 is attached and fixed to the downward-facing end face 9a of the tool holder 9, which is perpendicular to the axis P. As shown in the partially enlarged view of FIG. 3 in detail, an internally threaded hole 16 is formed in the end face 9a of the tool holder 9, and the guide tube 32 is fixed by a bolt 43 with the upper surface 41a of the mounting portion 41 aligned with the end face 9a of the tool holder 9. This allows the guide tube 32 to rotate together with the spindle 5 and cutting tool 8 of the milling machine 1.

[0021] 3, a through hole 45 is formed radially penetrating the peripheral wall near the mounting portion 41 on one end side of the guide tube 32. A guide hole 44 is formed inside the guide tube 32, extending axially from one end side (upper side in the figure) to the other end side (lower side in the figure). The through hole 45 is a hole for drawing the first conducting wire 13a drawn out from the tip 12 into the inside of the guide tube 32. The first conducting wire 13a introduced inside through the through hole 45 is fed along the guide hole 44 to the other end side of the guide tube 32.

[0022] The rotary connector 34 has a rotating portion 48 and a fixed portion 49 that are rotatable relative to each other around an axis. The rotating portion 48 is provided to protrude upward from the upward end face of the casing 50, and the fixed portion 49 is provided to protrude downward from the downward end face of the casing 50. In the rotary connector 34, the rotating portion 48 is rotatable relative to the casing 50 and the fixed portion 49 while the casing 50 and the fixed portion 49 are held non-rotatably by the holding arm 36. A rotating-side terminal 48a and a fixed-side terminal 49a are provided at the tips of the rotating portion 48 and the fixed portion 49, respectively, and the rotating-side terminal 48a and the fixed-side terminal 49a are arranged spaced apart in the axial direction.

[0023] A fluid contact (not shown) is provided inside the casing 50 of the rotary connector 34, and the rotating side terminal 48a and the fixed side terminal 49a are electrically connected by a fluid contact using a conductive fluid such as mercury.

[0024] 5, the rotating portion 48 of the rotary connector 34 is disposed at the other end (lower end) of the guide tube 32 so as to face the guide hole 44. The rotating portion 48 is connected to the guide tube 32 by a connecting pin 52 that is screwed radially inward at a step 46 that connects the small-diameter portion and the large-diameter portion of the guide tube 32, and is rotatable integrally with the guide tube 32. A first conducting wire 13a drawn from the tip 12 is connected to a rotating-side terminal 48a of the rotating portion 48. More specifically, the rotary connector 34 is connected so that the rotating-side terminal 48a is on the rotation axis (axis P) of the tool holder 9, which makes it possible to suppress runout of the first conducting wire 13a connected to the rotating-side terminal 48a when it rotates. In this example, a gap is provided between the rotating guide tube 32 and the non-rotating casing 50 of the rotary connector 34 to prevent interference, but it is also possible to adopt a configuration in which a bearing is interposed between the guide tube 32 and the casing 50 to suppress vibration of the lower part of the guide tube 32.

[0025] As shown in Figures 3 and 5, the holding arm 36 is a member that holds the casing 50 and fixed portion 49 of the rotary connector 34 so that they cannot rotate, and is equipped with a holding portion 54 that holds the rotary connector 34, an attachment portion 58 that is attached and fixed to the downward-facing underside 3a of the non-rotating spindle base 3, and a connecting portion 60 that connects the holding portion 54 and the attachment portion 58.

[0026] A through hole 55 extending in the axial direction is formed in the holding portion 54, and a holding surface 56 that abuts against the peripheral surface and lower end surface of the casing 50 of the rotary connector 34 is formed on the upper end side of the through hole 55. A part of the holding portion 54 is formed as a separation body 54b that can be separated from the holding portion main body 54a, and by sandwiching the casing 50 of the rotary connector 34 between the holding portion main body 54a and the separation body 54b, the casing 50 of the rotary connector 34 and the fixed portion 49 are held so that they cannot rotate.

[0027] The fixed portion 49 of the rotary connector 34 is arranged at one end (upper end) of the holding portion 54 so as to face the through hole 55, and the second conductor 13b connected to the fixed side terminal 49a of the fixed portion 49 is inserted through the through hole 55 and connected to the voltmeter 27 (see Figure 1).

[0028] In the cutting temperature measuring device 25 of this embodiment configured as described above, the cutting temperature during milling can be derived from the thermoelectromotive force between the tip and the workpiece, which is calculated based on the signal from the conductor 13 connected to the tip 12 and the signal from the conductor 22 connected to the workpiece W. Fig. 6 shows an example of a cutting temperature-machining time curve measured using the cutting temperature measuring device 25. T1 shown in the figure is the time it takes for the cutting tool 8 to make one rotation, and T2 is the time the cutting edge of the tip 12 is in contact with the workpiece W. The figure clearly shows the transition between cutting and idling, and it can be seen that a stable cutting temperature is obtained.

[0029] In this embodiment, during milling, the entire first conductor 13a is allowed to rotate together with the guide tube 32 and the rotating portion 48 of the rotary connector 34 in accordance with the rotation of the tip 12, thereby preventing twisting or breakage of the first conductor 13a. On the other hand, the second conductor 13b connected to the voltmeter 27 on the downstream side remains non-rotating even when the first conductor 13a rotates.

[0030] Here, the modifications to the milling machine 1 are limited to the formation of a screw hole 16 for attaching the measurement aid 30, and therefore, according to this embodiment, modifications to the milling machine 1 itself can be kept to a minimum, and the cutting temperature during milling can be easily measured using the tool-workpiece thermocouple method.

[0031] In addition, in this embodiment, the rotary connector 34 is arranged so that the rotation side terminal 48a is on the rotation axis of the tool holder 9, which makes it possible to suppress vibration when the first conducting wire 13a connected to the rotation side terminal 48a rotates.

[0032] Although the embodiments of the present invention have been described in detail above, these are merely examples. For example, in the above embodiment, the conductor 13 connecting the tip 12 and the voltmeter 27 is configured as two separate conductors, a first conductor and a second conductor, but it can also be configured as three or more separate conductors via connectors. Furthermore, in the above embodiment, the mounting portion 58 of the holding arm 36 is fixed to the spindle base 3, but it can also be fixed to a non-rotating portion other than the spindle base 3. For example, the present invention can be configured in various modified forms without departing from the spirit of the invention. [Explanation of symbols]

[0033] 1 Processing machine 9 Tool holder 12 chips 13a First Conductor 13b Second Conductor 25 Cutting temperature measuring device 30 Measuring aids 32 Guide tube 34 rotary connector 36 Holding arm 41 Mounting part 44 Guide hole 48 Rotating part 48a Rotation side terminal 49a Fixed side terminal P axis (rotation axis) W Workpiece (workpiece material)

Claims

1. A cylindrical guide tube having an attachment portion formed at one end thereof that is fixed to a tool holder that rotates together with the chip, and a guide hole formed inside thereof that guides a first conducting wire inserted from the one end into the guide hole to the other end; a rotary connector having a rotating-side terminal and a fixed-side terminal that are arranged axially apart and can rotate freely relative to each other, and a rotating portion connected to the other end of the guide tube so that the rotating-side terminal faces the guide hole; a holding arm for holding the rotary connector; Equipped with A measuring aid characterized in that the first conductor inserted into the guide hole is connected to a non-rotating second conductor via the rotating side terminal and fixed side terminal of the rotary connector.

2. A cutting temperature measuring device that measures the potential from each of the workpiece and the tip during milling and measures the cutting temperature from the thermoelectric power between the tip and the workpiece, The measuring aid according to claim 1 is configured to include: the mounting portion of the guide tube is fixed to the tool holder that holds the tip and rotates together with the tip; A cutting temperature measuring device characterized in that a signal from said tip is taken out via said first conducting wire and said second conducting wire.

3. 3. The cutting temperature measuring device according to claim 2, wherein the rotary connector is disposed so that the rotation side terminal is located on the rotation axis of the tool holder.

4. A method for measuring the cutting temperature from the thermoelectric power between the tip and the workpiece by measuring the potential from each of the workpiece and the tip during milling, Using the measurement aid according to claim 1, The mounting portion of the guide tube is fixed to the tool holder that holds the tip and rotates together with the tip; A cutting temperature measuring method, characterized in that a signal from said tip is taken out via said first conducting wire and said second conducting wire.

Images