Phase measuring method

Abstract

To provide a phase measuring method contributing to an improvement in the measurement accuracy of a rotational phase of a gear portion of a workpiece.SOLUTION: A phase measuring method of the present disclosure includes: a first step of moving a probe (P) to bring the probe (P) into contact with a gear portion (G); a second step of rotating a workpiece (W) to repeat the first step until an amount of movement of the probe (P) becomes equal to or larger than a threshold; a third step of moving a tip part of the probe (P) to a specific position; a fourth step of acquiring a first rotational phase of the workpiece (W) when the workpiece (W) is rotated and the probe (P) is brought into contact with one of tooth surfaces of the gear portion (G); a fifth step of acquiring a second rotational phase of the workpiece (W) when the workpiece (W) is rotated and the probe (P) is brought into contact with another of the tooth surfaces of the gear portion (G); and a sixth step of setting a rotational phase for a center of a tooth bottom (s3) of the gear portion (G), on the basis of the first rotational phase of the workpiece (W) and the second rotational phase of the workpiece (W).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a phase measurement method, for example, a method for measuring the rotational phase of a gear portion of a workpiece rotatably supported on a workpiece spindle of a machine tool by a probe supported on the machine tool. [Background technology]

[0002] For example, when machining a work supported by a machine tool, the position of a hole to be machined in the work may be important with respect to the rotational phase of a gear portion formed in the work, and therefore the rotational phase of the gear portion of the work supported by the machine tool is measured.

[0003] For example, the gear phase measurement method of Patent Document 1 involves bringing the tip of a probe close to the workpiece from the side of the workpiece, obtaining a first judgment result indicating whether the gear portion has been detected at a first detection position having a first angle in the circumferential direction of the gear portion of the workpiece, and bringing the tip of the probe close to the workpiece from the side of the workpiece, obtaining a second judgment result different from the first judgment result at a second detection position having a second angle in the circumferential direction of the gear portion of the workpiece.

[0004] The gear phase measurement method of Patent Document 1 then obtains a third angle between the first angle and the second angle, brings the tip of the probe close to the workpiece from the side of the workpiece, and obtains a third judgment result indicating whether the gear portion of the workpiece has been detected at a third detection position having a third angle in the circumferential direction of the gear portion of the workpiece.

[0005] Furthermore, the gear phase measuring method of Patent Document 1 replaces the first angle with the third angle if the third judgment result is the same as the first judgment result, and replaces the second angle with the third angle if the third judgment result is different from the first judgment result, and measures the rotational phase of the gear portion of the workpiece based on the angle from the first angle to the second angle. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6466633 Summary of the Invention [Problem to be solved by the invention]

[0007] The present applicant has found the following problem. The gear phase measuring method of Patent Document 1 repeatedly replaces the first angle or the second angle with a third angle, and when the difference between the first angle and the second angle is equal to or less than a threshold value, the first angle or the second angle is set as the rotational phase of the gear part of the workpiece. In other words, the gear phase measuring method of Patent Document 1 does not measure the rotational phase of the gear part by contacting a probe with the tooth surface of the gear part of the workpiece. Therefore, the gear phase measuring method of Patent Document 1 has a problem that it is difficult to accurately measure the rotational phase of the gear part of the workpiece.

[0008] The present disclosure has been made in consideration of such problems, and realizes a phase measurement method that contributes to improving the measurement accuracy of the rotational phase of a gear portion of a workpiece. [Means for solving the problem]

[0009] A phase measurement method according to one aspect of the present disclosure is a method for measuring a rotational phase of a gear portion of a workpiece rotatably supported on a workpiece spindle of a machine tool by a probe supported on the machine tool, comprising: a first step of moving the probe from a preset reference position in a radial direction of the workpiece to bring a tip of the probe into contact with a gear portion of the workpiece; a second step of repeating the first step by rotating the workpiece by a preset rotation amount until a radial movement amount of the workpiece at the tip of the probe becomes equal to or greater than a preset threshold value, and disposing the tip of the probe in a groove portion formed by opposing tooth surfaces and tooth bottoms of a gear portion of the workpiece; a third step of moving the tip of the probe to a predetermined position in the radial direction of the workpiece within a groove of a gear portion of the workpiece, where the amount of movement of the tip of the probe in the radial direction of the workpiece is a predetermined predetermined amount; a fourth step of rotating the workpiece in one direction after the third step is completed, and acquiring a first rotation phase of the workpiece with respect to the specified position when the tip of the probe is brought into contact with one tooth surface of a gear portion of the workpiece; a fifth step of rotating the workpiece in the other direction after the third step is completed, and acquiring a second rotation phase of the workpiece relative to the specified position when the tip of the probe is brought into contact with the other tooth surface of the gear portion of the workpiece; A sixth step of adding the first rotational phase of the workpiece and the second rotational phase of the workpiece together, and dividing the sum by two to obtain a rotational phase of a center of a tooth bottom of a gear portion of the workpiece; Equipped with.

[0010] In the above-described phase measurement method, the specified amount is preferably smaller than the threshold value.

[0011] In the above-described phase measuring method, it is preferable that the specified position is disposed radially outward of the work with respect to a reference circle of a gear portion of the work.

[0012] In the above-described phase measurement method, it is preferable that the probe is disposed above the workpiece and brought into contact with the gear portion of the workpiece by moving the probe downward from the reference position.

[0013] In the above-described phase measuring method, it is preferable that the machine tool rotatably supports both axial ends of the workpiece by the workpiece spindle. Effect of the Invention

[0014] According to the present disclosure, it is possible to contribute to improving the measurement accuracy of the rotational phase of a gear portion of a workpiece. [Brief description of the drawings]

[0015] [Figure 1] 1 is a diagram for explaining a representative example of the configuration of a machine tool on which a phase measurement method according to an embodiment is implemented; [Diagram 2] FIG. 2 is a flowchart showing the flow of a phase measurement method according to an embodiment. [Diagram 3] (a) is a view from the Y-axis - side showing the state when the tip of the probe is in contact with the gear portion of the workpiece, (b) is a view from the Y-axis - side showing the state when the tip of the probe has moved more than the threshold value, and (c) is a view from the Y-axis - side showing the state when the tip of the probe is positioned at a specified position. [Figure 4] 1A is a view from the Y-axis - side showing the state in which the workpiece is rotated in one direction and the tip of the probe is in contact with one tooth surface of the gear portion of the workpiece, and 1B is a view from the Y-axis - side showing the state in which the workpiece is rotated in the other direction and the tip of the probe is in contact with the other tooth surface of the gear portion of the workpiece. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, specific embodiments to which the present disclosure is applied will be described in detail with reference to the drawings. However, the present disclosure is not limited to the following embodiments. In addition, the following description and drawings are appropriately simplified for clarity of explanation.

[0017] First, a typical example of the configuration of a machine tool on which the phase measurement method of the present embodiment is implemented will be described. Fig. 1 is a diagram for explaining a typical example of the configuration of a machine tool on which the phase measurement method of the present embodiment is implemented.

[0018] Here, in the following explanation, for clarity, a three-dimensional (XYZ) coordinate system is used. Note that the X-axis + side is the front side of the machine tool, and the X-axis - side is the rear side of the machine tool. The Y-axis + side is the left side of the machine tool, and the Y-axis - side is the right side of the machine tool. The Z-axis + side is the top side of the machine tool, and the Z-axis - side is the bottom side of the machine tool.

[0019] The machine tool 1 can be configured, for example, as a turning center, and as shown in Fig. 1, is equipped with a tool spindle 2, a first work spindle 3, a second work spindle 4, and a tool rest 5. The tool spindle 2, the first work spindle 3, the second work spindle 4, and the tool rest 5 are each configured to perform operations similar to those of a general turning center by the driving forces of respective drive mechanisms controlled by, for example, a control device.

[0020] The tool spindle 2 is movable in the X-axis, Y-axis, and Z-axis directions. The tool spindle 2 is capable of supporting a tool, a probe, and the like. In the example shown in Fig. 1, the tool spindle 2 supports a probe P. The probe P detects, for example, contact with a workpiece W as described below.

[0021] The first work spindle 3 is capable of rotating around the Y axis. For example, as shown in Fig. 1, the first work spindle 3 is capable of supporting an end portion of the workpiece W on the + side of the Y axis, the end portion extending in the Y axis direction, by a chuck 3a.

[0022] As shown in Fig. 1, the second work spindle 4 is disposed so as to face the first work spindle 3 in the Y-axis direction. The second work spindle 4 is rotatable around the Y-axis. The second work spindle 4 is capable of supporting an end of the work W on the negative Y-axis side, for example, by a chuck 4a. In the illustrated example of Fig. 1, the first work spindle 3 and the second work spindle 4 support the work W having a gear portion G formed on the peripheral surface of a shaft-shaped member extending in the Y-axis direction.

[0023] The tool rest 5 may be, for example, a general turret, and is configured to be able to support a plurality of tools on the peripheral surface of the tool rest 5. The tool rest 5 is rotatable (pivotable) around the Y axis, and is also movable in the X-axis, Y-axis, and Z-axis directions.

[0024] When machining a workpiece W having a gear portion G formed thereon using such a machine tool 1, for example, the workpiece W may be removed from the first workpiece spindle 3 and the second workpiece spindle 4 once to be heat-treated, and then reattached to the first workpiece spindle 3 and the second workpiece spindle 4 after the heat treatment.

[0025] At this time, in order to machine holes or other gear portions at positions that are preset relative to the rotational phase of the gear portion G of the workpiece W, it may be necessary to measure the rotational phase of the gear portion G of the workpiece W.

[0026] Therefore, the phase measuring method of the present embodiment measures the rotational phase of the center of the tooth bottom of the gear portion G of the workpiece W supported by the first workpiece spindle 3 and the second workpiece spindle 4 of the machine tool 1 as follows. Note that the process of measuring the rotational phase of the center of the tooth bottom of the gear portion G of the workpiece W described below can be realized by the control device of the machine tool 1 or the like executing a program.

[0027] Fig. 2 is a flow chart showing the flow of the phase measurement method of this embodiment. Fig. 3(a) is a view from the Y-axis minus side showing a state where the tip of the probe contacts the gear part of the workpiece, Fig. 3(b) is a view from the Y-axis minus side showing a state where the tip of the probe has moved by more than a threshold, and Fig. 3(c) is a view from the Y-axis minus side showing a state where the tip of the probe is arranged at a specified position. Fig. 4(a) is a view from the Y-axis minus side showing a state where the workpiece is rotated in one direction and the tip of the probe contacts one tooth surface of the gear part of the workpiece, and Fig. 4(b) is a view from the Y-axis minus side showing a state where the workpiece is rotated in the other direction and the tip of the probe contacts the other tooth surface of the gear part of the workpiece.

[0028] First, the tool spindle 2 is moved so that the central axis C1 of the probe P is positioned approximately on a reference axis AX1 that passes through the central axis of the workpiece W and extends in the Z-axis direction, while the end portion (i.e., the tip portion) of the probe P on the Z-axis negative side is positioned on the Z-axis positive side with respect to the gear portion G of the workpiece W (S1).

[0029] In this state, the tool spindle 2 is moved to move the probe P to the negative Z-axis side from a reference position at a preset height in the Z-axis direction, and the negative Z-axis end of the probe P is brought into contact with the gear portion G of the workpiece W (S2), as shown in Fig. 3(a). Then, it is determined whether or not the amount of movement of the negative Z-axis end of the probe P in the Z-axis direction from the reference position to the state where the negative Z-axis end of the probe P comes into contact with the gear portion G of the workpiece W is equal to or greater than a preset threshold value (S3).

[0030] If the amount of movement of the end of the probe P on the negative side of the Z axis is less than the threshold (NO in S3), the first work spindle 3 and the second work spindle 4 are rotated to rotate the work W by a preset amount of rotation (S4), and the process returns to S2. In other words, the processes from S2 to S4 are repeated until the amount of movement of the end of the probe P on the negative side of the Z axis becomes equal to or greater than the threshold.

[0031] When the amount of movement of the negative Z-axis end of the probe P is equal to or greater than the threshold (YES in S3), as shown in Fig. 3(b), the negative Z-axis end of the probe P is disposed inside a groove g3 between teeth g1 and g2 adjacent to each other in the circumferential direction of the gear G of the workpiece W when viewed from the Y-axis direction. The groove g3 is formed by the tooth surface s1 of the tooth g1, the tooth surface s2 of the tooth g2 adjacent to the tooth g1, and the tooth bottom s3 between the tooth g1 and the tooth g2.

[0032] Next, as shown in Fig. 3(c), the tool spindle 2 is moved so that the movement amount of the end of the probe P on the negative side of the Z axis becomes a preset specified amount, and the tip of the probe P is moved to a specified position in the Z axis direction within the groove g3 of the gear portion G of the workpiece W (S5). At this time, it is preferable that the specified amount is smaller than the above-mentioned threshold value.

[0033] Therefore, the specified position is located on the tooth tip side of the gear portion G of the workpiece W with respect to the height position in the Z axis direction of the Z axis negative end of the probe P when the amount of movement of the Z axis negative end of the probe P is equal to or greater than the threshold value and the Z axis negative end of the probe P is in contact with the gear portion G of the workpiece W. Here, although detailed functions will be described later, it is preferable that the specified position is located radially outward of the workpiece W with respect to the reference circle R1 of the gear portion G in the workpiece W (including on the reference circle R1), as shown in FIG. 3(c).

[0034] Next, with the tip of the probe P positioned at a specified position, the first work spindle 3 and the second work spindle 4 are rotated to rotate the work W in one direction, and the end of the probe P on the Z-axis - side is brought into contact with the tooth surface s2 of the tooth portion g2 as shown in Figure 4(a), and the first rotational phase of the work W from the specified position in that state is obtained (S6).

[0035] Next, the first work spindle 3 and the second work spindle 4 are rotated in the other direction, and the tip of the probe P is again placed at the specified position. Then, the first work spindle 3 and the second work spindle 4 are rotated to rotate the work W in the other direction, and the end of the probe P on the negative Z-axis side is brought into contact with the tooth surface s1 of the tooth portion g1 as shown in Fig. 4(b), and a second rotation phase of the work W from the specified position in that state is obtained (S7).

[0036] Next, the rotational phase of the center C2 of the tooth bottom s3 of the gear portion G of the work W is obtained based on the first rotational phase of the work W and the second rotational phase of the work W (S8). For example, the first rotational phase of the work W and the second rotational phase of the work W are added together, and the sum of the rotational phases is divided by 2 to obtain the rotational phase of the center C2 of the tooth bottom s3 of the gear portion G of the work W.

[0037] In detail, for example, when viewed from the negative side of the Y axis, in the state of Fig. 3(c), the specified position is set to 0 deg around the central axis of the workpiece W, the clockwise direction is set to the negative direction, and the counterclockwise direction is set to the positive direction. Then, when the state of Fig. 3(c) is changed to the state of Fig. 4(a), +2.4 deg is obtained as the first rotation phase of the workpiece W, and then the workpiece W is returned to the state of Fig. 3(c) again, and then the workpiece W is changed to the state of Fig. 4(b), and -5.4 deg is obtained as the second rotation phase of the workpiece W. In this way, the rotation phase of the center C2 of the tooth bottom s3 of the gear portion G of the workpiece W relative to the specified position can be obtained.

[0038] In this case, as described above, when the specified position is located radially outside the workpiece W with respect to the reference circle R1 of the gear portion G of the workpiece W, the first rotational phase and the second rotational phase of the workpiece W can be obtained at a point where the distance between the tooth surface s1 of the adjacent tooth portion g1 and the tooth surface s2 of the tooth portion g2 in the gear portion G of the workpiece W is wider toward the bottom s3 side, and the measurement accuracy of the rotational phase of the center C2 of the bottom s3 of the gear portion G of the workpiece W can be improved.

[0039] Thereafter, for example, based on previously acquired specification data of the gear portion G of the workpiece W and data indicating the rotational phase of the center C2 of the tooth bottom s3 of the gear portion G of the workpiece W, the positions for machining holes, other gear portions, etc. are calculated relative to the rotational phase of the gear portion G, and the first workpiece spindle 3, the second workpiece spindle 4 and the tool post 5 are operated so that holes, other gear portions, etc. are machined at the calculated positions, thereby machining the workpiece W.

[0040] In this manner, the phase measuring method of this embodiment brings the Z-axis minus end of the probe P into contact with the tooth surface s1 of the adjacent tooth g1 and the tooth surface s2 of the tooth g2, and obtains the rotational phase of the center C2 of the tooth bottom s3 between the tooth g1 and the tooth g2. Therefore, the phase measuring method of this embodiment can measure the rotational phase of the gear portion G of the workpiece W more accurately than the gear phase measuring method of Patent Document 1.

[0041] Moreover, in the phase measuring method of this embodiment, the probe P is brought close to the workpiece W from the radial direction to obtain the rotational phase of the center C2 of the tooth bottom s3 of the gear portion G of the workpiece W. Therefore, when both ends of the workpiece W in the Y-axis direction are supported by the first workpiece spindle 3 and the second workpiece spindle 4 as described above, it is difficult to bring the probe into contact with the gear portion of the workpiece from the side thereof as in the gear phase measuring method of Patent Document 1, for example. However, in the phase measuring method of this embodiment, the probe P can easily be brought into contact with the gear portion G of the workpiece W.

[0042] In this embodiment, the probe P is moved in the Z-axis direction to obtain the rotational phase of the center C2 of the bottom s3 of the gear portion G of the workpiece W, but it is also possible to obtain the rotational phase of the center C2 of the bottom s3 of the gear portion G of the workpiece W by moving the probe P in the radial direction of the workpiece W.

[0043] In addition, in this embodiment, the workpiece W is supported by the first workpiece spindle 3 and the second workpiece spindle 4, but the same can be implemented even if the workpiece W is supported by either the first workpiece spindle 3 or the second workpiece spindle 4.

[0044] The present disclosure is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit and scope of the present disclosure. [Explanation of symbols]

[0045] 1 machine tool 2 Tool spindle 3 1st work spindle, 3a chuck 4 Second work spindle, 4a Chuck 5 Tool rest AX1 Reference axis C1 Center axis of workpiece C2 Center of the bottom of the gear part of the workpiece G Gear section g1, g2 teeth g3 Groove P-Probe R1 Reference circle s1, s2 tooth surface s3 tooth root W work

Claims

1. A method for measuring a rotational phase of a gear portion of a workpiece rotatably supported on a workpiece spindle of a machine tool by a probe supported on the machine tool, comprising: a first step of moving the probe from a preset reference position in a radial direction of the workpiece to bring a tip of the probe into contact with a gear portion of the workpiece; a second step of repeating the first step by rotating the workpiece by a preset rotation amount until a radial movement amount of the workpiece at the tip of the probe becomes equal to or greater than a preset threshold value, and disposing the tip of the probe in a groove portion formed by opposing tooth surfaces and tooth bottoms of a gear portion of the workpiece; a third step of moving the tip of the probe to a predetermined position in the radial direction of the workpiece within a groove of a gear portion of the workpiece, where the amount of movement of the tip of the probe in the radial direction of the workpiece is a predetermined predetermined amount; a fourth step of rotating the workpiece in one direction after the third step is completed, and acquiring a first rotation phase of the workpiece with respect to the specified position when the tip of the probe is brought into contact with one tooth surface of a gear portion of the workpiece; a fifth step of rotating the workpiece in the other direction after the third step is completed, and acquiring a second rotation phase of the workpiece with respect to the specified position when the tip of the probe is brought into contact with the other tooth surface of the gear portion of the workpiece; A sixth step of adding the first rotational phase of the workpiece and the second rotational phase of the workpiece together, and dividing the sum by two to obtain a rotational phase of a center of a tooth bottom of a gear portion of the workpiece; A phase measurement method comprising:

2. The method of claim 1 , wherein the prescribed amount is small relative to the threshold value.

3. 3. The phase measuring method according to claim 1, wherein the specified position is disposed radially outward of the work with respect to a reference circle of a gear portion of the work.

4. 3. The phase measuring method according to claim 1, wherein the probe is disposed above the workpiece and is brought into contact with the gear portion of the workpiece by moving the probe downward from the reference position.

5. 5. The phase measuring method according to claim 4, wherein the machine tool rotatably supports both axial ends of the workpiece by the workpiece spindle.

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