Phase determination 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, it relates to a method of measuring the rotational phase of a gear portion of a workpiece rotatably supported on a work spindle of a machine tool by a probe supported on the machine tool.

Background Art

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

[0003] For example, in the gear phase measurement method of Patent Document 1, the tip of a probe is brought close to the workpiece from the side of the workpiece, and a first determination result indicating whether or not the gear portion is detected at a first detection position having a first angle in the circumferential direction of the gear portion of the workpiece is obtained. Then, the tip of the probe is brought close to the workpiece from the side of the workpiece, and a second determination result different from the first determination result is obtained at a second detection position having a second angle in the circumferential direction of the gear portion of the workpiece.

[0004] And, the gear phase measurement method of Patent Document 1 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 determination result indicating whether or not the gear portion is detected at a third detection position having the third angle in the circumferential direction of the gear portion of the workpiece.

[0005] Furthermore, in the gear phase measurement method of Patent Document 1, if the third determination result and the first determination result are the same, the first angle is replaced with the third angle, and if the third determination result and the first determination result are different, the second angle is replaced with the third angle, and the rotational phase of the gear portion of the workpiece is measured based on the angle from the first angle to the second angle.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Patent No. 6466633 [Overview of the Initiative] [Problems that the invention aims to solve]

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

[0008] This disclosure has been made in view of these problems and realizes a phase measurement method that contributes to improving the accuracy of measuring the rotational phase of the 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 the rotational phase of a gear portion of a workpiece rotatably supported on the spindle of a machine tool using a probe supported on the machine tool, A first step involves moving the probe from a preset reference position in the radial direction of the workpiece so that the tip of the probe comes into contact with the gear portion of the workpiece. The first step is repeated by rotating the workpiece by a predetermined amount of rotation until the amount of radial movement of the workpiece at the tip of the probe exceeds a predetermined threshold, thereby positioning the tip of the probe within the groove formed by the opposing tooth surfaces and tooth roots of the gear portion of the workpiece. A third step of moving the tip of the probe to a predetermined radial position of the workpiece within the groove of the gear portion of the workpiece, such that the amount of radial movement of the workpiece at the tip of the probe is a predetermined amount. A fourth step is to rotate the workpiece in one direction after the third step is completed and to obtain the first rotational 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 the gear portion of the workpiece. A fifth step is to rotate the workpiece to the other side after the third step is completed, and to obtain the second rotational 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 involves adding the first rotational phase of the workpiece and the second rotational phase of the workpiece, and dividing the summed rotational phase by 2 to obtain the rotational phase of the center of the tooth root of the gear portion of the workpiece. It is equipped with.

[0010] In the phase measurement method described above, it is preferable that the specified amount is small compared to the threshold.

[0011] In the phase measurement method described above, it is preferable that the specified position is located radially outward of the workpiece with respect to the reference circle of the gear portion of the workpiece.

[0012] In the phase measurement method described above, it is preferable that the probe is positioned above the workpiece and moved downward from the reference position to make contact with the gear portion of the workpiece.

[0013] In the phase measurement method described above, it is preferable that the machine tool supports both axial ends of the workpiece by the workpiece spindle so that they can rotate. [Effects of the Invention]

[0014] According to this disclosure, it is possible to improve the accuracy of measuring the rotational phase of the gear portion of a workpiece. [Brief explanation of the drawing]

[0015] [Figure 1] This is a diagram for explaining a representative example of the configuration of a machine tool in which the phase measurement method of the embodiment is implemented. [Figure 2] This is a flowchart showing the flow of the phase measurement method of the embodiment. [Figure 3] (a) is a view seen from the Y-axis - side of the state where the tip of the probe contacts the gear part of the workpiece, (b) is a view seen from the Y-axis - side of the state where the tip of the probe has moved more than the threshold value, and (c) is a view seen from the Y-axis - side of the state where the tip of the probe is arranged at the specified position. [Figure 4] (a) is a view seen from the Y-axis - side of the 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 (b) is a view seen from the Y-axis - side of the 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.

Mode for Carrying Out the Invention

[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. Also, for clarity of explanation, the following description and drawings are simplified as appropriate.

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

[0018] Here, in the following description, for clarity of explanation, it will be described using a three-dimensional (XYZ) coordinate system. Note that the + side of the X-axis is the front side of the machine tool, and the - side of the X-axis is the rear side of the machine tool. The + side of the Y-axis is the left side of the machine tool, and the - side of the Y-axis is the right side of the machine tool. The + side of the Z-axis is the upper side of the machine tool, and the - side of the Z-axis is the lower side of the machine tool.

[0019] The working machine 1 can be configured, for example, as a turning center. As shown in FIG. 1, it includes 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 force of respective drive mechanisms controlled by, for example, a control device.

[0020] The tool spindle 2 is movable in the X-axis direction, Y-axis direction, and Z-axis direction. The tool spindle 2 can support tools, probes, etc. In the illustrated example of FIG. 1, the tool spindle 2 supports a probe P. The probe P detects contact with the work W, for example, as will be described later.

[0021] The first work spindle 3 is rotatable about the Y-axis. The first work spindle 3 can support, for example, as shown in FIG. 1, the end portion on the +Y side of the work W extending in the Y-axis direction by a chuck 3a.

[0022] The second work spindle 4 is arranged to face the first work spindle 3 in the Y-axis direction as shown in FIG. 1. The second work spindle 4 is rotatable about the Y-axis. The second work spindle 4 can support, for example, the end portion on the -Y side of the work W by a chuck 4a. In the illustrated example of FIG. 1, the first work spindle 3 and the second work spindle 4 support a work W having a gear portion G formed on the peripheral surface of a shaft-like member extending in the Y-axis direction.

[0023] The tool rest 5 is preferably, for example, a general turret, and is configured to be able to support a plurality of tools on its peripheral surface. The tool rest 5 is rotatable (swingable) about the Y-axis and is movable in the X-axis direction, Y-axis direction, and Z-axis direction.

[0024] When machining a workpiece W on which a gear section G is formed 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 for heat treatment, and then reattached to the first workpiece spindle 3 and the second workpiece spindle 4 after the heat treatment.

[0025] In this case, it may be necessary to measure the rotational phase of the gear section G of the workpiece W in order to machine holes or other gear sections at a predetermined position relative to the rotational phase of the gear section G of the workpiece W.

[0026] Therefore, the phase measurement method of this embodiment measures the rotational phase of the center of the tooth root 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 described below. Note that the process of measuring the rotational phase of the center of the tooth root of the gear portion G of the workpiece W described below can be realized by the control device of the machine tool 1 executing a program.

[0027] Figure 2 is a flowchart showing the flow of the phase measurement method of this embodiment. Figure 3(a) is a view from the Y-axis side showing the state in which the tip of the probe is in contact with the gear portion of the workpiece, Figure 3(b) is a view from the Y-axis side showing the state in which the tip of the probe has moved beyond a threshold, and Figure 3(c) is a view from the Y-axis side showing the state in which the tip of the probe is positioned at a predetermined location. Figure 4(a) 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 Figure 4(b) 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.

[0028] First, the tool spindle 2 is moved (S1) such 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, and the Z-axis-side end (i.e., the tip) of the probe P is positioned on the Z-axis+ side relative to the gear portion G of the workpiece W.

[0029] In this state, the tool spindle 2 is moved to move the probe P from a preset reference position at a height in the Z-axis direction toward the Z-axis side, so that the Z-axis side end of the probe P comes into contact with the gear portion G of the workpiece W, as shown in Figure 3(a) (S2). Then, it is determined whether the amount of movement of the Z-axis side end of the probe P from the reference position until the Z-axis side end of the probe P comes into contact with the gear portion G of the workpiece W in the Z-axis direction is greater than or equal to a preset threshold (S3).

[0030] If the amount of movement of the Z-axis-side end of probe P is less than the threshold (NO in S3), the first work spindle 3 and the second work spindle 4 are rotated to rotate the workpiece W by a preset amount (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 Z-axis-side end of probe P is greater than or equal to the threshold.

[0031] If the amount of movement of the Z-axis-side end of probe P is greater than or equal to the threshold (YES for S3), as shown in Figure 3(b), the Z-axis-side end of probe P is positioned inside the groove g3 between circumferentially adjacent teeth g1 and teeth g2 in the gear portion G of the workpiece W, as viewed from the Y-axis direction. The groove g3 is formed by the tooth surface s1 of tooth g1, the tooth surface s2 of tooth g2 adjacent to tooth g1, and the tooth root s3 between tooth g1 and tooth g2.

[0032] Next, as shown in Figure 3(c), the tool spindle 2 is moved so that the amount of movement of the Z-axis end of the probe P becomes a predetermined amount, thereby moving the tip of the probe P to a predetermined position in the Z-axis direction within the groove g3 of the gear portion G of the workpiece W (S5). At this time, the predetermined amount should be small compared to the threshold value mentioned above.

[0033] Therefore, the specified position is positioned on the tooth tip side of the gear portion G of the workpiece W, relative to the height position in the Z-axis direction of the Z-axis end of the probe P when the amount of movement of the Z-axis end of the probe P is greater than or equal to a threshold and the Z-axis end of the probe P is in contact with the gear portion G of the workpiece W. Here, although the detailed function will be described later, the specified position is preferably positioned radially outward of the workpiece W with respect to the reference circle R1 of the gear portion G of the workpiece W (however, including on the reference circle R1), as shown in Figure 3(c).

[0034] Next, with the tip of the probe P positioned in the specified location, the first work spindle 3 and the second work spindle 4 are rotated to rotate the workpiece W in one direction, and as shown in Figure 4(a), the Z-axis-side end of the probe P is brought into contact with the tooth surface s2 of the tooth portion g2, and the first rotational phase of the workpiece 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 to the other side, and the tip of the probe P is again positioned at the specified location. Then, the first work spindle 3 and the second work spindle 4 are rotated to rotate the workpiece W to the other side, and as shown in Figure 4(b), the Z-axis side end of the probe P is brought into contact with the tooth surface s1 of the tooth portion g1, and the second rotational phase of the workpiece W from the specified position in that state is obtained (S7).

[0036] Next, the rotational phase of the center C2 of the tooth root s3 of the gear portion G of the workpiece W is obtained based on the first rotational phase of the workpiece W and the second rotational phase of the workpiece W (S8). For example, the first rotational phase of the workpiece W and the second rotational phase of the workpiece W are added together, and the value obtained by dividing the sum of the rotational phases by 2 is taken as the rotational phase of the center C2 of the tooth root s3 of the gear portion G of the workpiece W.

[0037] In detail, for example, when viewed from the Y-axis side, in the state shown in Figure 3(c), the central axis of the workpiece W is defined as 0 degrees, clockwise is the negative direction, and counterclockwise is the positive direction. Then, when changing from the state in Figure 3(c) to the state in Figure 4(a), a first rotational phase of +2.4 degrees is obtained for the workpiece W. After returning to the state in Figure 3(c) and then changing the workpiece W to the state in Figure 4(b), a second rotational phase of -5.4 degrees is obtained for the workpiece W. In this case, ((+2.4)+(-5.4))÷2=-1.5 degrees is the rotational phase of the center C2 of the tooth root s3 of the gear part G of the workpiece W. This allows us to obtain the rotational phase of the center C2 of the tooth root s3 of the gear part G of the workpiece W relative to the defined position.

[0038] In this case, as described above, if the specified position is located radially outward of the workpiece W with respect to the reference circle R1 of the gear portion G of the workpiece W, the first and second rotational phases of the workpiece W can be obtained at a location where the gap between the tooth surface s1 of adjacent tooth portion g1 and the tooth surface s2 of tooth portion g2 in the gear portion G of the workpiece W is wider on the side of the tooth root s3, thereby improving the measurement accuracy of the rotational phase of the center C2 of the tooth root s3 of the gear portion G of the workpiece W.

[0039] Subsequently, for example, based on the previously acquired specification data of the gear section G of the workpiece W and data indicating the rotational phase of the center C2 of the tooth root s3 of the gear section G of the workpiece W, the position for machining holes and other gear sections is calculated relative to the rotational phase of the gear section G. By operating the first workpiece spindle 3, the second workpiece spindle 4, and the tool post 5 so that holes and other gear sections are machined at the calculated positions, the workpiece W can be machined.

[0040] As described above, the phase measurement method of this embodiment involves bringing the Z-axis-side end of the probe P into contact with the tooth surface s1 of adjacent tooth portion g1 and the tooth surface s2 of tooth portion g2, thereby obtaining the rotational phase of the center C2 of the tooth root s3 between tooth portion g1 and tooth portion g2. Therefore, the phase measurement method of this embodiment can accurately measure the rotational phase of the gear portion G of the workpiece W compared to the gear phase measurement method of Patent Document 1.

[0041] Furthermore, the phase measurement method of this embodiment acquires the rotational phase of the center C2 of the tooth root s3 of the gear portion G of the workpiece W by bringing the probe P close to the workpiece W from the radial direction. Therefore, as described above, 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, it is difficult to bring the probe into contact with the gear portion of the workpiece from the side, as in the gear phase measurement method of Patent Document 1, for example. However, the phase measurement method of this embodiment allows the probe P to easily come 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 tooth root s3 of the gear portion G of the workpiece W. However, the probe P can be moved in the radial direction of the workpiece W to obtain the rotational phase of the center C2 of the tooth root s3 of the gear portion G of the workpiece W.

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

[0044] This disclosure is not limited to the embodiments described above, and may be modified as appropriate without departing from the spirit of the invention. [Explanation of Symbols]

[0045] 1 machine tool 2 Tool spindle 3. First workpiece spindle, 3a chuck 4. Second workpiece spindle, 4a chuck 5. Tool rest AX1 Reference axis C1 Workpiece central axis Center of the tooth root of the gear section of the C2 workpiece G Gear section g1, g2 teeth g3 Groove P probe R1 Base Yen s1, s2 tooth surface s3 tooth root Double job

Claims

1. A method for measuring the rotational phase of a gear portion of a workpiece rotatably supported on the spindle of a machine tool using a probe supported by the machine tool, A first step involves moving the probe from a preset reference position in the radial direction of the workpiece so that the tip of the probe comes into contact with the gear portion of the workpiece. The first step is repeated by rotating the workpiece by a preset amount of rotation until the amount of radial movement of the workpiece from the reference position at the tip of the probe exceeds a preset threshold, thereby positioning the tip of the probe within the groove formed by the opposing tooth surfaces and tooth roots of the gear portion of the workpiece. A third step is to move the tip of the probe to a predetermined position in the radial direction of the workpiece within the groove of the gear portion of the workpiece, such that the amount of movement of the tip of the probe from the reference position to the radial direction of the workpiece is a predetermined amount set to be smaller than the threshold, A fourth step is to rotate the workpiece in one direction after the third step is completed and to obtain the first rotational 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 the gear portion of the workpiece. A fifth step is to rotate the workpiece to the other side after the third step is completed, and to obtain the second rotational 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 involves adding the first rotational phase of the workpiece and the second rotational phase of the workpiece, and dividing the summed rotational phase by 2 to obtain the rotational phase of the center of the tooth root of the gear portion of the workpiece. A phase measurement method comprising the following features.

2. The phase measurement method according to claim 1, wherein the specified position is located radially outward of the workpiece with respect to the reference circle of the gear portion of the workpiece.

3. The phase measurement method according to claim 1 or 2, wherein the probe is positioned above the workpiece and moved downward from the reference position to contact the gear portion of the workpiece.

4. The phase measurement method according to claim 3, wherein the machine tool supports both axial ends of the workpiece by the workpiece spindle so as to be rotatable.

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