Error correction method
The method corrects tooth trace direction errors in multi-tasking machines by combining Z-axis movements with X-axis or Y-axis directions, addressing precision and productivity issues without requiring high-precision motor control, thus improving machine performance.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2024-11-07
- Publication Date
- 2026-05-19
AI Technical Summary
Existing multi-tasking machines face challenges in achieving precision and productivity due to tooth trace direction errors caused by support rigidity and require high-precision motor control, making error correction difficult.
A method for correcting tooth trace direction errors by moving the hob tool in the Z-axis direction combined with perpendicular movements in the X-axis or Y-axis directions, depending on the desired correction direction, allowing independent error correction on right and left tooth surfaces.
This method enables easy and effective correction of tooth trace errors, ensuring both productivity and accuracy without the need for high-precision motor control, enhancing multi-tasking machine performance.
Smart Images
Figure 2026082337000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a method for correcting an error in the tooth trace direction in hobbing of a machining center.
Background Art
[0002] In recent years, due to the reduction in the number of machine tools, an integrated technology for production processes using machining centers has attracted attention.
[0003] Generally, when hobbing a workpiece with a hob tool, the hob tool is operated to approach the workpiece while rotating around its axis. For example, FIGS. 3(a) and 3(b) show a related hobbing machine in a state where the hob tool and the workpiece are synchronously rotated and the hob tool is operated only in the Z-axis direction.
[0004] The hob tools shown in FIGS. 3(a) and 3(b) are arranged to have an intersection angle according to the twist angle of the gear as the workpiece, but show a state where the intersection angle does not change during machining.
Prior Art Documents
Patent Documents
[0005]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0006] However, when hobbing a workpiece with a hob tool, the machining resistance acts as a load on the rotation of the hob tool. Therefore, as shown in FIG. 3(c), errors in the actual tooth trace direction occur on the right tooth surface and the left tooth surface with respect to the ideal tooth trace. Note that, as shown in FIG. 3(c), the error directions in the actual tooth trace direction on the right tooth surface and the left tooth surface with respect to the ideal tooth trace may be in different directions.
[0007] Patent Document 1 discloses a method for correcting tooth trace errors by slightly shifting the rotational synchronization between the synchronized tool axis and the workpiece axis.
[0008] However, the support rigidity of the hob cutter in a multi-tasking machine is lower than that of a dedicated machine (hobbing machine) due to the need for various movements and interference constraints. Therefore, it is difficult to ensure the same level of precision and productivity as a dedicated machine in a multi-tasking machine. Furthermore, in order to ensure precision and productivity, it is necessary to correct for errors in the tooth trace direction caused by the support rigidity.
[0009] Furthermore, the tooth trace correction method disclosed in Patent Document 1 requires high-precision motor control in the machine tool, making its implementation difficult. Therefore, there has been a need for an error correction method that can easily correct errors in the tooth trace direction.
[0010] This disclosure provides an error correction method for correcting errors in the tooth trace direction in an easy-to-implement manner. [Means for solving the problem]
[0011] The error correction method according to this disclosure is a method for correcting errors in the tooth trace direction when hobbing a workpiece with a hob tool provided on a multi-tasking machine, wherein the hob tool and the workpiece are arranged side by side in the Z-axis direction and rotate synchronously, and when it is desired to correct the tooth trace direction error on the right tooth surface and the left tooth surface in the same direction, the hob tool is moved in the Z-axis direction while moving in the X-axis direction which is perpendicular to the Z-axis direction, and when it is desired to correct the tooth trace direction error on the right tooth surface and the left tooth surface in opposite directions, the hob tool is moved in the Z-axis direction while moving in the Y-axis direction which is perpendicular to both the Z-axis direction and the X-axis direction. This allows for the correction of tooth trace errors independently on the right and left tooth surfaces by combining the two actions. [Effects of the Invention]
[0012] This disclosure provides an error correction method for correcting errors in the tooth trace direction in an easy-to-implement manner. [Brief explanation of the drawing]
[0013] [Figure 1] This figure shows the operation of a tool provided in the multi-tasking machine according to Embodiment 1. [Figure 2] This figure shows the correction of tooth trace errors in a multi-tasking machine according to Embodiment 1. [Figure 3] This diagram shows the operation of the related multi-tasking machine and the error in the tooth trace. [Modes for carrying out the invention]
[0014] Embodiment 1 The operation of the hob tool 11 provided in the multi-tasking machine 1 according to this embodiment will be described below with reference to the drawings. The object to be machined by the multi-tasking machine 1 will be referred to as workpiece 2. Here, a multi-tasking machine is defined as a machine tool that has at least two axes, either a rotary AB axis or a BC axis, in addition to the three orthogonal XYZ axes.
[0015] In the following, the terms "right tooth surface" and "left tooth surface" refer to those conforming to JIS standards. The right tooth surface is the tooth surface to the right of the tooth at the 12 o'clock position in a top view, and the left tooth surface is the tooth surface to the left of the tooth at the 12 o'clock position in a top view.
[0016] Figures 1(a) and 1(b) show the positional relationship between the hob tool 11 and the workpiece 2 of the multi-tasking machine 1, and the direction of operation of the hob tool 11. Here, the hob tool 11 and the workpiece 2 are assumed to be aligned in the Z-axis direction.
[0017] Figure 1(a) shows the left-right direction as the Z-axis direction and the up-down direction as the X-axis direction. In the following explanation, the X-axis, Y-axis, and Z-axis directions are assumed to be orthogonal to each other. Here, the operation shown in Figure 1(a) will be described as the first correction operation.
[0018] In Fig. 1(a), the thin-line arrows around the axes described for the hob tool 11 and the workpiece 2 respectively indicate the rotational motions of the hob tool 11 and the workpiece 2 involved in hob machining. Note that the hob tool 11 and the workpiece 2 are rotating synchronously. As shown in Fig. 1(a), the workpiece 2 is rotating around the Z axis, and the rotation axis of the hob tool 11 is in a direction slightly inclined in the Z-axis direction from a state close to being parallel to the X-axis direction.
[0019] Also, the thick-line arrow in Fig. 1(a) indicates an example of the operation direction of the hob tool 11. That is, the hob tool 11 moves in the X-axis direction and also moves in the Z-axis direction so as to approach the workpiece 2.
[0020] Particularly, for the hob tool 11, while the hob machining is in progress with contact against the workpiece 2, a force for moving in the X-axis direction acts, and a state is reached where a force for moving in the Z-axis direction also acts.
[0021] Note that as shown by the thick-line arrow in Fig. 1(a), for the hob tool 11, the force applied to move in the X-axis direction can be made smaller than the force applied to move in the Z-axis direction.
[0022] On the other hand, Fig. 1(b) is a diagram showing the left-right direction as the Z-axis direction and the up-down direction as the Y-axis direction. Here, the operation shown in Fig. 1(b) will be described as the second correction operation.
[0023] Also in Fig. 1(b), similar to Fig. 1(a), the thin-line arrows around the axes described for the hob tool 11 and the workpiece 2 respectively indicate the rotational motions of the hob tool 11 and the workpiece 2 involved in hob machining.
[0024] Also, the thick-line arrow in Fig. 1(b) indicates an example of the operation direction of the hob tool 11. That is, the hob tool 11 moves in the Y-axis direction and also moves in the Z-axis direction so as to approach the workpiece 2.
[0025] In particular, with the hob tool 11, while it is in contact with the workpiece 2 and hobbing is progressing, a force acting in the Y-axis direction acts as well as a force acting in the Z-axis direction.
[0026] Furthermore, as shown by the thick arrow in Figure 1(b), the force acting on the hob tool 11 to move in the Y-axis direction can be made smaller than the force acting to move in the Z-axis direction.
[0027] Next, with reference to Figures 2(a) and 2(b), the correction of tooth trace errors by the first and second correction operations will be explained.
[0028] Here, Figure 2(a) shows an example of tooth trace error correction corresponding to the first correction operation shown in Figure 1(a). In other words, as shown in Figure 2(a), in the multi-tasking machine 1, the right and left tooth surfaces can be corrected to the same orientation by moving the hob tool 11 in the Z-axis direction while moving it in the X-axis direction.
[0029] On the other hand, Figure 2(b) shows an example of tooth trace error correction corresponding to the second correction operation shown in Figure 1(b). In other words, as shown in Figure 2(b), in the multi-tasking machine 1, the right and left tooth surfaces can be corrected in opposite directions by moving the hob tool 11 in the Z-axis direction while moving it in the Y-axis direction.
[0030] Therefore, by combining the first and second correction operations, independent error correction in the tooth trace direction can be achieved for the right and left tooth surfaces. In other words, the multi-tasking machine 1 can perform error correction in the tooth trace direction in any direction, either in the same direction or in opposite directions, for both the right and left tooth surfaces.
[0031] Here, for example, if the amount of correction on the right tooth surface is A and the amount of correction on the left tooth surface is B, then as shown in Figures 2(a) and 2(b), the correction amounts x and y for tooth trace error are, x = (A + B) / 2 y = (AB) / 2 Therefore, by specifying the required amount of modification, hobbing can be performed to achieve the desired shape.
[0032] To put it another way, in the multi-tasking machine 1, if you want to correct the error in the tooth trace direction of the right tooth surface and the left tooth surface to the same direction, you can adjust the correction state by moving the hob tool 11 in the Z direction while moving it in the X direction. On the other hand, in the multi-tasking machine 1, if you want to correct the error in the tooth trace direction of the right tooth surface and the left tooth surface to opposite directions, you can adjust the correction state by moving the hob tool 11 in the Z direction while moving it in the Y direction.
[0033] For the sake of clarity, Figures 1(a) and 1(b) above only show the movement direction of the hob tool 11 as linear motion, but this is not the only option. For example, in the multi-tasking machine 1, it is also possible to move the hob tool 11 so that it bends at any point, or to move it in an arc.
[0034] According to the method described above, tooth trace direction errors caused by the support rigidity in the multi-tasking machine 1 are corrected, making it possible to achieve both productivity and the required accuracy.
[0035] Furthermore, with the multi-tasking machine 1, high-precision motor control is not required, and errors in the tooth trace direction can be corrected using an easy-to-implement method.
[0036] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. In other words, the above description has been omitted and simplified as appropriate for the sake of clarity, and those skilled in the art can easily change, add, and modify each element of the embodiments within the scope of the present invention. [Explanation of symbols]
[0037] 1 Multi-tasking machine 2 Work 11 Hob Tools
Claims
[Claim 1] A method for correcting errors in the tooth trace direction when hobbing a workpiece using a hob tool provided on a multi-tasking machine, The hob tool and the workpiece are arranged side by side in the Z-axis direction and are rotating synchronously. If you want to correct the error in the tooth trace direction on the right tooth surface and the left tooth surface to be in the same direction, you can move the hob tool in the direction perpendicular to the Z-axis direction, while moving it in the Z-axis direction. If you want to correct the error in the tooth trace direction on the right tooth surface and the left tooth surface in opposite directions, you move the hob tool in the Z-axis direction while moving it in the Y-axis direction, which is perpendicular to the Z-axis direction and the X-axis direction. Error correction method.