Grinding wheel forming method, grinding wheel forming apparatus, and gear grinding apparatus
Patent Information
- Application Number
- JP2024099149
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-06-19
- Publication Date
- 2026-01-07
Smart Images
Figure 2026001642000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a grinding wheel molding method, a grinding wheel molding device, and a gear grinding device. [Background technology]
[0002] Conventionally, in gear grinding machines that use a threaded grinding wheel to machine various gears, the tooth flank of the grinding wheel is modified by dressing to improve machining accuracy (see, for example, Patent Document 1). Dressing is performed, for example, using a disk-shaped rotary dresser. The rotary dresser is used to perform an operation along the side of the groove of the grinding wheel, and the grinding wheel shape required for gear machining is transferred from the shape of the rotary dresser. The grinding wheel shaped in this way can be used to shape the tooth flank of a gear. [Prior art documents] [Patent documents]
[0003] [Patent Document 1] Patent No. 6133131 Summary of the Invention [Problem to be solved by the invention]
[0004] When dressing a grinding wheel, it is desirable to create a rotary dresser that is shaped to match the shape of the gear tooth flank. However, the design shape of the rotary dresser may not completely match the actual shape of the rotary dresser. If a rotary dresser with a shape different from the design shape is used, the grinding wheel forming accuracy may be reduced.
[0005] The present invention has been made in view of the above-mentioned problems, and aims to provide a grinding wheel molding method, a grinding wheel molding device, and a gear grinding device that can improve the molding accuracy of the grinding wheel. [Means for solving the problem]
[0006] One aspect of the present invention is A method for forming a grinding wheel having grooves, comprising the steps of: Acquire a reference position of a reference rotary dresser with respect to the groove, assuming that the side surface of the groove of the grinding wheel is formed using the reference rotary dresser having a reference cross-sectional shape; acquiring an actual cross-sectional shape of an actual rotary dresser formed based on the reference rotary dresser; calculating a positional correction amount of the actual rotary dresser relative to the reference position so as to reduce a positional error between the actual cross-sectional shape and the reference cross-sectional shape while forming the side surface of the groove using the actual rotary dresser; The grindstone shaping method corrects the position correction amount with respect to the reference position, and shapes the side surface of the groove using the actual rotary dresser.
[0007] Another aspect of the present invention is A molding device for a grinding wheel having grooves, a grindstone support member that supports the grindstone rotatably around a grindstone shaft; a rotary dresser that is rotatably supported around a rotary dresser shaft and shapes the side surface of the groove of the rotating grinding wheel; a control device that moves at least one of the grinding wheel and the rotary dresser to a desired position and controls the rotation thereof to shape the side surface of the groove of the grinding wheel; The control device Acquire a reference position of a reference rotary dresser with respect to the groove, assuming that the side surface of the groove of the grinding wheel is formed using the reference rotary dresser having a reference cross-sectional shape; acquiring an actual cross-sectional shape of an actual rotary dresser formed based on the reference rotary dresser; calculating a positional correction amount of the actual rotary dresser relative to the reference position so as to reduce a positional error between the actual cross-sectional shape and the reference cross-sectional shape while forming the side surface of the groove using the actual rotary dresser; The grindstone shaping device corrects the position correction amount with respect to the reference position and shapes the side surface of the groove using the actual rotary dresser.
[0008] Yet another aspect of the present invention is a method for producing a semiconductor device comprising: A gear grinding apparatus for grinding a gear tooth surface using a grinding wheel formed by the above-described grinding wheel forming method, a grindstone support member that supports the grindstone rotatably around a grindstone shaft; a gear support member that supports the gear rotatably around the workpiece axis; and a control device that moves at least one of the grinding wheel and the gear to a desired position and controls the rotation to grind the tooth surface of the gear. [Effects of the Invention]
[0009] According to one aspect and another aspect of the present invention, in the dressing process of the grinding wheel, the position error between the reference cross-sectional shape of the reference rotary dresser and the actual cross-sectional shape of the actual rotary dresser can be reduced, thereby improving the forming accuracy of the grinding wheel.
[0010] According to yet another aspect of the present invention, a gear can be ground with high precision using a grinding wheel.
[0011] As described above, according to the above aspects, it is possible to provide a grinding wheel molding method, a grinding wheel molding device, and a gear molding device that are capable of improving the molding accuracy of the grinding wheel. [Brief explanation of the drawings]
[0012] [Figure 1] 1 is a front view showing a gear grinding device according to a first embodiment. [Figure 2]In the first embodiment, (a) is a partially enlarged view showing the cross-sectional shape of a gear grinding wheel, (b) is a partially enlarged view showing the reference cross-sectional shape of a reference rotary dresser corresponding to the cross section taken along line II-II in FIG. 1, and (c) is a partially enlarged view showing the actual cross-sectional shape of an actual rotary dresser taken along line II-II in FIG. [Figure 3] FIG. 1 is a diagram showing the cross-sectional shape of a gear grinding wheel according to the first embodiment, the reference cross-sectional shape of a reference rotary dresser, and the actual cross-sectional shape of an actual rotary dresser, and is a partially enlarged view showing a state in which point A1 of the gear grinding wheel, point A2 of the reference cross-sectional shape of the reference rotary dresser, and point A3 of the actual cross-sectional shape of the actual rotary dresser are aligned. [Figure 4] 3 is a diagram showing a reference cross-sectional shape and an actual cross-sectional shape in the first embodiment. FIG. [Figure 5] 1A and 1B are diagrams showing a state in which the actual cross-sectional shape has been corrected in the radial direction R in the first embodiment, in which FIG. 1A shows a state in which the correction has been made using one end of the radial direction R as a reference, and FIG. 1B shows a state in which the correction has been made using an arbitrary point on the reference cross-sectional shape and an arbitrary point on the actual cross-sectional shape as a reference. [Figure 6] FIG. 10 is a diagram showing a perpendicular bisector at a distance calculation point of an actual cross-sectional shape in the first embodiment. [Figure 7] FIG. 3 is a diagram showing the intersection of a perpendicular bisector and a straight line in the reference cross-sectional shape in the first embodiment. [Figure 8] 10 is a diagram showing a state in which the actual cross-sectional shape is moved by a predetermined amount in the left-right direction L in the first embodiment. FIG. [Figure 9] 10 is a diagram showing a process of correcting the actual cross-sectional shape with respect to the rotation angle θ in the first embodiment. FIG. [Figure 10] 10 is a diagram showing a state in which a position correction amount is calculated for an actual cross-sectional shape and the actual cross-sectional shape is moved based on the position correction amount in the first embodiment. FIG. [Figure 11] FIG. 2 is a diagram showing a state in which a gear grinding wheel is being shaped by an actual rotary dresser in the first embodiment. [Figure 12]In the first embodiment, (a) is a diagram showing the cross-sectional shape of a gear grinding wheel, the reference cross-sectional shape of a reference rotary dresser, and the actual cross-sectional shape of an actual rotary dresser, and (b) is a diagram showing the state in which the gear grinding wheel is being formed by the actual rotary dresser whose position has been corrected. [Figure 13] 1 is a flowchart showing the overall steps of dressing in the first embodiment. [Figure 14] 4 is a flowchart showing an evaluation function calculation process in the first embodiment. [Figure 15] 10 is a flowchart showing an L-direction correction process in the first embodiment. [Figure 16] 10 is a flowchart showing a sum-of-squares calculation process in the first embodiment. [Figure 17] 10 is a flowchart showing a rotation angle θ correction process in the first embodiment. DETAILED DESCRIPTION OF THE INVENTION
[0013] (Embodiment 1) 1. Gear grinding equipment 1 A first embodiment will be described with reference to Figure 1. A gear grinding apparatus 1 according to this embodiment includes a dressing device 30. The gear grinding apparatus 1 grinds the tooth flanks of a gear using a gear grinding wheel T (an example of a grinding wheel). The dressing device 30 also shapes the side surfaces of grooves 40 in the gear grinding wheel T.
[0014] The gear grinding machine 1 includes a bed 2, an X-axis guide (not shown), a column 3, a Y-axis guide 4, a Y-axis slide 5, a rotating member 6, a Z-axis guide 7, a Z-axis slide 8, a grinding wheel support member 9, a gear grinding wheel T, a workpiece support member 10, a rotary dresser support member 11, a rotary dresser 12, a control device 13, and a memory device 14. The bed 2 is installed on an installation surface. The column 3 is guided by an X-axis guide installed on the upper surface of the bed 2 and is installed so as to be movable in the X-axis direction (horizontal direction) relative to the bed 2. Although not shown in detail, the column 3 is driven by a ball screw mechanism, a linear motor, or the like.
[0015] The dressing device 30 includes a grinding wheel support member 9, a rotary dresser 12, and a control device 13. The dressing device 30 is an example of a molding device for a grinding wheel T for gear grinding.
[0016] The Y-axis slide 5 is guided by a Y-axis guide 4 provided on a side surface of the column 3 extending in the vertical direction, and is provided so as to be movable in the Y-axis direction (up and down) relative to the column 3. The rotation member 6 is provided on the Y-axis slide 5 and is provided so as to be rotatable around the A-axis, which is a horizontal axis. The rotation member 6 is provided so as to be rotatable within a range of 360°, for example.
[0017] Z-axis slide 8 is guided by Z-axis guide 7, which is provided on the upper surface of bed 2 and perpendicular to the X-axis guide, and is provided so as to be movable in the Z-axis direction (horizontal direction) relative to bed 2. Although not shown in detail, Z-axis slide 8 is driven by a ball screw mechanism, a linear motor, or the like.
[0018] The grindstone support member 9 is provided on the rotating member 6, and rotates when the rotating member 6 rotates around the A axis.
[0019] The grinding wheel support member 9 supports the gear grinding wheel T so that it can rotate around the C axis. The C axis coincides with the grinding wheel axis direction Ct of the gear grinding wheel T and is an axis line parallel to the Z axis direction. The gear grinding wheel T has a spiral grinding blade that protrudes radially outward. The gear grinding wheel T may have a single-start thread or a multiple-start thread. In the case of a multiple-start thread, the gear grinding wheel T has multiple spiral grinding blades.
[0020] The workpiece support member 10 is provided on the Z-axis slide 8 and supports the workpiece W rotatably around the Cg axis by the motor M1.
[0021] The rotary dresser support member 11 is provided on the Z-axis slide 8 and supports the rotary dresser 12 so that the rotary dresser 12 can rotate around the Cd axis by the motor M2.
[0022] The gear grinding machine 1 according to this embodiment is a six-axis machine, i.e., a machine having three linear axes and three rotational axes. However, the gear grinding machine 1 is not limited to a six-axis machine. In this embodiment, the gear grinding machine 1 is configured so that the workpiece W can rotate about the Cg axis, the gear grinding wheel T can rotate about the A axis, the gear grinding wheel T can move in the X-axis and Y-axis directions, and the workpiece W can move in the Z-axis direction. The A-axis is an axis perpendicular to the central axis of the workpiece W and the grinding wheel axis direction Ct of the gear grinding wheel T. The C-axis coincides with the grinding wheel axis direction Ct (central axis) of the gear grinding wheel T.
[0023] The gear grinding device 1 is configured so that the rotary dresser 12 can rotate around the Cd axis and can move in the Z axis direction.
[0024] The control device 13 is configured, for example, by a CPU (Central Processing Unit), a PLC (Programmable Logic Controller), or a CNC (Computerized Numerical Control) device. The control device 13 is configured to grind the tooth flank of the first gear with the gear grinding wheel T by rotating the first gear 21 and the gear grinding wheel T synchronously while controlling the relative positions of the first gear 21 and the gear grinding wheel T, so that an axial direction Cg of the first gear 21 (described later) and an axial direction Ct of the gear grinding wheel T form a predetermined crossing axis angle.
[0025] The control device 13 is configured to rotate the gear grinding wheel T and the rotary dresser 12 synchronously and to control the relative positions of the gear grinding wheel T and the rotary dresser 12, thereby allowing the rotary dresser 12 to shape the side surfaces of the grooves 40 of the gear grinding wheel T. The rotary dresser 12 according to this embodiment is a forming device.
[0026] The storage device 14 may be a known storage device 14 such as a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk drive, or a USB (Universal Serial Bus) memory. The storage device 14 may be located in the gear grinding machine 1 or may be a server connected via a network (not shown).
[0027] The feed direction of the gear grinding wheel T may be both a direction along the central axis of the workpiece W and a direction in which the central axis of the workpiece W and the central axis of the gear grinding wheel T approach each other, or it may be only a direction in which the central axis of the workpiece W and the central axis of the gear grinding wheel T approach each other.
[0028] As shown in FIG. 1 , the workpiece W according to this embodiment includes a shaft 20, a first gear 21, and a second gear 22. The shaft 20 is formed in a long cylindrical shape. The first gear 21 and the second gear 22 are formed side by side at an interval in the longitudinal direction of the shaft 20. In this embodiment, the diameter of the first gear 21 is smaller than the diameter of the second gear 22. However, the diameter of the first gear 21 may be the same as or larger than the diameter of the second gear 22. When the workpiece W is placed on the workpiece support member 10, the axis of the shaft 20 and the B axis are arranged parallel to each other.
[0029] In this embodiment, the gear grinding wheel T grinds the tooth flank of the first gear 21. However, the gear grinding wheel T may grind the tooth flank of the second gear 22, or may grind the tooth flank of the first gear 21 and the tooth flank of the second gear 22.
[0030] 2. Gear grinding wheel T The gear grinding wheel T according to this embodiment is a threaded grinding wheel formed in the shape of a helical gear. The outer shape of the gear grinding wheel T is not particularly limited, and may be cylindrical, hourglass-shaped, or barrel-shaped. The gear grinding wheel T may also be configured to have a shape (cup-shaped) that tapers from one end of the gear grinding wheel T to the other end.
[0031] 3. Rotary Dresser 12 The rotary dresser 12 is formed in a disk shape. The rotary dresser 12 is rotatably supported by a rotary dresser support member 11 so as to rotate around a Cd axis within a horizontal plane. The rotation axis of the rotary dresser 12 and the Cd axis are arranged coaxially.
[0032] As shown in Fig. 1, the cutting edge 31 of the disk-shaped rotary dresser 12 has an acute-angled cross section, and contact portions 32 that come into contact with the side surfaces of the grooves 40 in the gear grinding wheel T are formed on one or both of the upper and lower surfaces. Fig. 1 illustrates an example in which the contact portions 32 are formed on both the upper and lower surfaces. However, the contact portions 32 may be formed on either the upper or lower surface of the rotary dresser 12. Diamond grains are uniformly attached to the entire surfaces of the cutting edge 31 and the contact portions 32.
[0033] In this embodiment, the gear grinding wheel T is configured to move in the left-right direction (Z direction), the front-back direction (X direction), and the up-down direction (Y direction) in Fig. 1, and the rotary dresser 12 is configured to move in the left-right direction (Z direction) in Fig. 1. As a result, the rotary dresser 12 and the gear grinding wheel T move relatively in the Z direction, and the rotary dresser 12 performs desired dressing on the side surface of the groove 40 of the gear grinding wheel T.
[0034] 4. Cross-sectional shape of the rotary dresser 12 The cross-sectional shape of the rotary dresser 12 will be described with reference to FIGS.
[0035] 4-1. Gear grinding wheel T FIG. 2(a) shows a portion of the cross-sectional shape of gear grinding wheel T. Gear grinding wheel T has a groove 40. The side surface of groove 40 is formed by rotary dresser 12. A curved surface S1 is formed on the inner side surface of groove 40 on the left side L1 in the left-right direction L in FIG. 2(a). The curved surface S1 is indicated by a thick solid line. One end of curved surface S1 in the radial direction R in FIG. 2(a) is connected to the bottom surface of groove 40. The other end of curved surface S1 in the radial direction R in FIG. 2(a) is connected to point A1. Groove 40 opens downward in the radial direction R in FIG. 2(a) at point A1.
[0036] 4-2. Reference rotary dresser 12a A reference rotary dresser 12a having a reference cross-sectional shape 51 of the rotary dresser 12 is designed to form the side surface of the groove 40 of the gear grinding wheel T into a desired shape. FIG. 2(b) shows a portion of the reference cross-sectional shape 51 of the reference rotary dresser 12a. The reference cross-sectional shape 51 has a shape that is a transfer of at least a portion of the shape of the side surface of the groove 40 of the first gear 21. If the rotary dresser 12 having the reference cross-sectional shape 51 is designated as the reference rotary dresser 12a, and it is assumed that the side surface of the groove 40 of the gear grinding wheel T is formed using the reference rotary dresser 12a, the position of the reference rotary dresser 12a with respect to the groove 40 is defined as the reference position.
[0037] The shape of the reference rotary dresser 12a according to this embodiment is designed to be narrower in the left-right direction L in FIG. 2(b) than the cross dimension of the groove 40 of the gear grinding wheel T. This is intended to form each side of the groove 40 one side at a time, rather than simultaneously forming both side surfaces of the groove 40 in the left-right direction L of the gear grinding wheel T. It is preferable to simultaneously form both side surfaces of the groove 40 of the gear grinding wheel T using the rotary dresser 12, as this improves the efficiency of the gear grinding wheel T forming process. However, as described above, the shape of the actual actual rotary dresser 12b may differ from the design, and therefore a positional correction may be made to the reference position of the reference rotary dresser 12a. If a positional correction is made to the actual rotary dresser 12b, there is a risk that the actual rotary dresser 12b may interfere with a portion of the gear grinding wheel T that is not the grinding target. Therefore, in order to avoid interference with the gear grinding wheel T, the shape of the standard rotary dresser 12a according to this embodiment is designed to be narrower in the left-right direction L than the cross dimension of the groove 40 of the gear grinding wheel T.
[0038] The reference rotary dresser 12a has a cutting edge 31a at its tip in the radial direction R. The reference rotary dresser 12a according to FIG. 2(b) has a contact portion 32a on the left side L1 of the cutting edge 31a in the left-right direction L in FIG. 2(b). One end of the contact portion 32a in the radial direction R is continuous with the cutting edge 31a. The other end of the contact portion 32a in the radial direction R is continuous with point A2. The portion of the reference rotary dresser 12a below point A2 in the radial direction R in FIG. 2(b) is formed in a flat shape.
[0039] When the reference rotary dresser 12a is placed at a reference position where points A1 and A2 are aligned, the curved surface S2 on the left side L1 of the contact portion 32a of the reference rotary dresser 12a has a shape that is a transcription of the shape of the curved surface S1 of the groove 40 of the gear grinding wheel T (see FIG. 3). The curved surface S2 is indicated by a thick solid line.
[0040] FIG. 2(c) shows a portion of an actual cross-sectional shape 52, which is a cross-sectional shape of an actual rotary dresser 12b formed based on the reference rotary dresser 12a. The actual rotary dresser 12b has a cutting edge 31b at its tip in the radial direction R. The actual rotary dresser 12b of FIG. 2(c) has a contact portion 32b on the left L1 side of the cutting edge 31b in the left-right direction L in FIG. 2(c). One end of the contact portion 32b in the radial direction R is continuous with the cutting edge 31b. The other end of the contact portion 32b in the radial direction R is continuous with point A3. A portion of the actual rotary dresser 12b below point A3 in the radial direction R in FIG. 2(c) is formed in a flat shape.
[0041] Of the contact portion 32b of the actual rotary dresser 12b, a curved surface S3 on the left L1 side in the left-right direction L comes into contact with the curved surface S1 of the groove 40 of the gear grinding wheel T to form the curved surface S1. The curved surface S3 is indicated by a thick solid line.
[0042] As shown in FIGS. 2(b) and 2(c), there are cases where the reference cross-sectional shape 51 of the reference rotary dresser 12a, which is the design shape, does not completely match the actual cross-sectional shape 52 of the actual rotary dresser 12b that is actually formed.
[0043] 4-3. Cross-sectional shapes of the gear grinding wheel T, the reference rotary dresser 12a, and the actual rotary dresser 12b 3 shows a state in which the left end and point A1 of the cross-sectional shape of the gear grinding wheel T in FIG. 2(a), the left end and point A2 of the reference cross-sectional shape 51 of the reference rotary dresser 12a in FIG. 2(b), and the left end and point A3 of the actual cross-sectional shape 52 of the actual rotary dresser 12b in FIG. 2(c) are aligned. The following describes the differences between the reference cross-sectional shape 51 of the reference rotary dresser 12a and the actual cross-sectional shape 52 of the actual rotary dresser 12b. However, the manner of difference between the reference cross-sectional shape 51 of the reference rotary dresser 12a and the actual cross-sectional shape 52 of the actual rotary dresser 12b is not limited to the following description.
[0044] As shown in Fig. 3, for example, the width dimension in the left-right direction L in Fig. 3 of the reference cross-sectional shape 51 of the reference rotary dresser 12a is smaller than the width dimension in the left-right direction L in Fig. 3 of the groove 40 of the gear grinding wheel T. This is because, when taking into consideration correcting the position of the actual rotary dresser 12b when dressing the side surface of the groove 40 of the gear grinding wheel T with the actual rotary dresser 12b, interference between the actual rotary dresser 12b and a portion of the side surface of the groove 40 of the gear grinding wheel that is different from the side surface of the grinding target is suppressed. Note that the left-right direction L in Fig. 2 is an example of two linear axes.
[0045] 3, for example, the outer diameter of the actual rotary dresser 12b in the radial direction R in Fig. 3 is smaller than the inner diameter of the gear grinding wheel T in the radial direction R in Fig. 3. This is because, when the position of the actual rotary dresser 12b is corrected when the side surface of the groove 40 of the gear grinding wheel T is dressed by the actual rotary dresser 12b, interference of the actual rotary dresser 12b with a portion of the side surface of the groove 40 of the gear grinding wheel that is different from the side surface of the object to be ground is suppressed.
[0046] 3, for example, the curved surface S2 of the reference cross-sectional shape 51 of the reference rotary dresser 12a and the curved surface S3 of the actual cross-sectional shape 52 of the actual rotary dresser 12b are different. The width dimension of the actual rotary dresser 12b in the left-right direction L in FIG. 3 is larger than the width dimension of the reference rotary dresser 12a in the left-right direction L in FIG. 3. However, the width dimension of the actual rotary dresser 12b in the left-right direction L in FIG. 3 may be smaller than the width dimension of the reference rotary dresser 12a in the left-right direction L in FIG. 3.
[0047] If an attempt is made to form the side surface of the groove 40 of the gear grinding wheel T at the above-mentioned reference position using an actual rotary dresser 12b having an actual cross-sectional shape 52 different from the reference cross-sectional shape 51, it would be difficult to form the cross-sectional shape of the gear grinding wheel T into the designed shape.
[0048] Therefore, in this embodiment, as will be described below, in a state where the actual rotary dresser 12b is used to form the side surface of the groove 40 of the gear grinding wheel, a position correction amount of the actual rotary dresser 12b with respect to the reference position is calculated so that the position error between the actual cross-sectional shape 52 and the reference cross-sectional shape 51 becomes small, and the position correction amount is corrected with respect to the reference position, and the side surface of the groove 40 is formed using the actual rotary dresser 12b.
[0049] 5. Method for calculating the position correction amount of the actual rotary dresser 12b A method for calculating the position correction amount of the actual rotary dresser 12b will be described with reference to Figures 4 to 10. However, the method for calculating the position correction amount of the actual rotary dresser 12b is not limited to the following description.
[0050] (1) First, the control device 13 acquires point cloud data of the reference cross-sectional shape 51 of the reference rotary dresser 12a and point cloud data of the cross-sectional shape of the actual rotary dresser 12b. The point cloud data of the reference cross-sectional shape 51 can be acquired from the design data of the reference rotary dresser 12a. The point cloud data of the actual cross-sectional shape 52 can be acquired by measuring the shape of the actual rotary dresser 12b using a known three-dimensional shape measurement method. The three-dimensional shape measurement method is not particularly limited, and for example, a contact method using a probe or a non-contact method using laser light may be used. The control device 13 stores the point cloud data of the reference cross-sectional shape 51 of the reference rotary dresser 12a and the point cloud data of the actual cross-sectional shape 52 of the actual rotary dresser 12b in the storage device 14.
[0051] In Fig. 4, the reference cross-sectional shape 51 of the reference rotary dresser 12a is shown by a dashed line, and the actual cross-sectional shape 52 of the actual rotary dresser 12b is shown by a solid line. Of the point cloud data of the reference cross-sectional shape 51, six points on the surface (corresponding to the curved surface S2) on the left side L1 side in the left-right direction L in Fig. 4 are representatively shown by filled-in symbols, and six points on the surface (corresponding to the curved surface S3) on the left side L1 side of the point cloud data of the actual cross-sectional shape 52 are representatively shown by filled-in symbols. The same applies to Figs. 5 to 10.
[0052] (2) Next, the control device 13 calculates an evaluation function relating to the amount of position correction based on the point group.
[0053] The parameters for calculating the evaluation function are not particularly limited, and any parameters can be used, such as the dimension in the radial direction R, the dimension in the left-right direction L, or the rotation angle θ of the actual rotary dresser 12b (described later).
[0054] The evaluation function is not particularly limited, and may be calculated, for example, based on the distance D (an example of a normal error) between each point in the normal direction of each point of the point cloud and a reference cross-sectional shape 51, which will be described later. The evaluation function may be, for example, the sum of squares of the distances D, the root mean square of the distances D, the arithmetic mean of the distances D, the geometric mean of the distances D, or the harmonic mean of the distances D, and any evaluation function can be selected.
[0055] (3) Next, the control device 13 calculates the position correction amount so that the evaluation function becomes smaller. The method for calculating the position correction amount so that the evaluation function becomes smaller is not particularly limited, and any method can be used. In this embodiment, for example, the position correction amount can be calculated so that the evaluation function becomes smaller as shown in the following (4) to (14).
[0056] (4) The control device 13 calculates a radius difference, which is the difference between the radius at the outermost point of the reference cross-sectional shape 51 and the radius at the outermost point of the actual cross-sectional shape 52, in the radial direction R of the rotary dresser 12. As shown in FIG. 5(a), the actual cross-sectional shape 52 is translated in the radial direction R so as to make the radius difference zero. The radial direction R is an example of two linear axes.
[0057] However, the point for making the radius difference zero is not particularly limited, and as shown in FIG. 5(b), a configuration may be adopted in which an arbitrary point P2 on the curved surface S2 of the reference cross-sectional shape 51 and an arbitrary point P3 on the curved surface S3 of the actual cross-sectional shape 52 are translated so that the radius difference becomes zero. In this case, the rotation center of the rotation angle θ, which will be described later, can be the points P2 and P3. Also, as shown in FIG. 4, a configuration may be adopted in which a point A2 on the reference cross-sectional shape 51 and a point A3 on the actual cross-sectional shape 52 are translated so that the radius difference becomes zero. In this case, the rotation center of the rotation angle θ can be the points A2 and A3.
[0058] (5) Next, as shown in Fig. 6, control device 13 sets a point on the outer surface of actual cross-sectional shape 52 as distance calculation point 52a. Control device 13 calculates a perpendicular bisector PL (an example of a normal line) passing through distance calculation point 52a from three consecutive points including distance calculation point 52a and two points before and after distance calculation point 52a. However, if distance calculation point 52a is the extreme end point, control device 13 calculates a perpendicular line (an example of a normal line) to a line connecting this extreme end point.
[0059] (6) The control device 13 calculates the distance (an example of a normal error) between the perpendicular bisector PL and all point cloud data of the reference cross-sectional shape 51. The control device 13 calculates, from the point cloud data of the reference cross-sectional shape 51, two points that are the shortest distance from the perpendicular bisector PL.
[0060] (7) As shown in Fig. 7, the control device 13 calculates an intersection 51a between a straight line SL connecting two points calculated from the point cloud data of the reference cross-sectional shape 51 and a perpendicular bisector PL calculated from the point cloud data of the actual cross-sectional shape 52. The control device 13 calculates a distance D between the intersection 51a and a distance calculation point 52a set in the point cloud data of the actual cross-sectional shape 52.
[0061] (8) The control device 13 executes the above-described processes (5) to (7) for all points on the left side L1 in the left-right direction L of the actual cross-sectional shape 52. As a result, the control device 13 calculates the distance D described in the above-described (5) for all points on the left side L1 in the left-right direction L of the actual cross-sectional shape 52, and calculates the sum of squares of the distance D (an example of an evaluation function) based on this distance D. The control device 13 stores this sum of squares in the storage device 14 as a first sum of squares SS1.
[0062] (9) As shown in FIG. 8 , the control device 13 adds or subtracts the position of the actual cross-sectional shape 52 in the left-right direction L to move the actual cross-sectional shape 52 in the left-right direction L. Whether the position in the left-right direction L is added or subtracted is arbitrary, and may be determined in advance or by random numbers. The distance to be moved is arbitrary, and may be a fixed amount, random, or may be a fixed amount with momentum taken into consideration. The control device 13 executes the above-described processes (5) to (8) on the point cloud data of the actual cross-sectional shape 52 moved in the left-right direction L. As a result, the control device 13 calculates the sum of squares of the distance D based on the actual cross-sectional shape 52 moved in the left-right direction L. The control device 13 stores this sum of squares in the storage device 14 as a second sum of squares SS2.
[0063] (10) The control device 13 compares the first sum of squares SS1 with the second sum of squares SS2, and if the second sum of squares SS2 is smaller than the first sum of squares SS1, moves the actual cross-sectional shape 52 in the same direction as the direction in which the actual cross-sectional shape 52 was moved in the left-right direction L when calculating the second sum of squares SS2.
[0064] On the other hand, the control device 13 compares the first sum of squares SS1 with the second sum of squares SS2, and if the second sum of squares SS2 is greater than the first sum of squares SS1, moves the actual cross-sectional shape 52 in the opposite direction to the direction in which the actual cross-sectional shape 52 was moved in the left-right direction L when calculating the second sum of squares SS2.
[0065] However, the control device 13 may be configured to compare the first sum of squares SS1 and the second sum of squares SS2, and if the first sum of squares SS1 and the second sum of squares SS2 are the same, move the actual cross-sectional shape 52 in any direction in the left-right direction L. The direction of movement may be determined, for example, by generating a random number and determining whether the random number is odd or even, to move the actual cross-sectional shape 52 to the left L1 or right L2 in the left-right direction L, or it may be determined in advance whether the actual cross-sectional shape 52 is moved to the left L1 or right L2 when the first sum of squares SS1 and the second sum of squares SS2 are the same.
[0066] (11) The control device 13 repeats the above-described processes (5) to (10), and if the direction of movement in the left-right direction L changes continuously, the control device 13 temporarily terminates the calculation of the position in the left-right direction L. A case where the direction of movement in the left-right direction L changes continuously is, for example, a case where the actual cross-sectional shape 52 is moved to the left L1 in the left-right direction L and then moved to the right L2 in the left-right direction L in the next trial. Similarly, a case where the cross-sectional shape is moved to the right L2 in the left-right direction L and then moved to the left L1 in the left-right direction L in the next trial also corresponds to a case where the direction of movement in the left-right direction L changes continuously.
[0067] (12) Next, the control device 13 executes the above-described processes (5) to (11) using, as a variable, the rotation angle θ when the actual cross-sectional shape 52 is rotated while the position of the actual cross-sectional shape 52 in the left-right direction L is fixed. In detail, in the above-described descriptions (5) to (11), the left-right direction L is read as the rotation angle θ, the left side L1 of the left-right direction L is read as the clockwise direction θ1 of the rotation angle θ in Fig. 9, and the right side of the left-right direction L is read as the counterclockwise direction θ2 of the rotation angle θ in Fig. 9. Since the rest of the description is the same as the descriptions of (5) to (11), redundant explanations will be omitted.
[0068] (13) When the process related to the rotation angle θ is completed, the control device 13 again alternately executes the processes (5) to (10) related to the left-right direction L and the process (11) related to the rotation angle θ. However, either the process related to the left-right direction L or the process related to the rotation angle θ may be executed first.
[0069] (14) The control device 13 ends the above-described processes (5) to (12) on the condition that the evaluation function is minimum. The condition for determining whether the evaluation function is minimum is arbitrary. For example, the control device 13 may use the convergence of the fluctuations in the sum of squares calculated as the evaluation function as a condition, or may determine that the evaluation function is minimum when other conditions are satisfied.
[0070] For example, when the condition is whether the fluctuation in the sum of squares has converged, the control device 13 compares the sum of squares of the distance D that converged when the left-right direction L was changed with the sum of squares of the distance D that converged when the rotation angle θ was changed. In this case, for example, if the absolute value of the difference between the sum of squares of the distance D that converged when the left-right direction L was changed and the sum of squares of the distance D that converged when the rotation angle θ was changed is smaller than a predetermined threshold, it may be determined that the sum of squares has converged. Alternatively, for example, the control device 13 may calculate the average value (e.g., arithmetic mean, geometric mean, harmonic mean, etc.) of the sum of squares of the distance D that converged when the left-right direction L was changed and the sum of squares of the distance D that converged when the rotation angle θ was changed, and determine that the sum of squares has converged if this average value is smaller than a predetermined threshold.
[0071] In addition, the control device 13 may calculate the sum of squares of the smallest distance D based on a combination of the sum of squares of all distances D calculated in the left-right direction L and the sum of squares of all distances D calculated for the rotation angle θ.
[0072] 10, it is possible to reduce the position error between the curved surface S3 on the left side L1 in the left-right direction L of the actual cross-sectional shape 52 and the curved surface S2 on the left side L1 in the left-right direction L of the reference cross-sectional shape 51. In this way, it is possible to calculate the position correction amount with respect to the reference position for the curved surface S3 on the left side L1 in the left-right direction L of the actual rotary dresser 12b.
[0073] However, the position correction amount relative to the reference position may be calculated by a computer (not shown) separate from the gear grinding machine 1 , and the calculated position correction amount may be transmitted to the control device 13 .
[0074] 6. Total forming method of grinding wheel Based on the position correction amount calculated in 5 above, the actual rotary dresser 12b is used to form the side of the groove 40 in the gear grinding wheel T. As shown in Fig. 11, the curved surface S3 on the left side L1 in the left-right direction L of the actual rotary dresser 12b is brought into contact with the curved surface S1 on the left side L1 in the left-right direction L of the groove 40 in the gear grinding wheel T, thereby forming the curved surface S1 on the left side L1 in the left-right direction L of the groove 40 in the gear grinding wheel T. This makes it possible to form the side of the groove 40 in the gear grinding wheel T with high precision using the actual rotary dresser 12b.
[0075] 12(a), the position correction amount may be calculated for the curved surface U1 on the right L2 side in the left-right direction L of the groove 40 of the gear grinding wheel T, the curved surface U2 on the right L2 side in the left-right direction L of the reference rotary dresser 12a, and the curved surface U3 on the right L2 side in the left-right direction L of the actual rotary dresser 12b in the same manner as for the curved surface S3 on the left L1 side in the left-right direction L of the actual rotary dresser 12b. As a result, as shown in FIG. 12(b), the curved surface U1 on the right L2 side in the left-right direction L of the groove 40 of the gear grinding wheel T may be formed by the curved surface U3 on the right L2 side in the left-right direction L of the actual rotary dresser 12b.
[0076] However, the position correction amount may be calculated for both the left side L1 and the right side L2 of one actual rotary dresser 12b in the left-right direction L. Also, a configuration may be adopted in which one actual rotary dresser 12b for which the position correction amount is calculated only for the curved surface S3 on the left side L1 in the left-right direction L and another actual rotary dresser 12b for which the position correction amount is calculated only for the curved surface U3 on the right side L2 in the left-right direction L are used to form the curved surface S1 on the left side L1 in the left-right direction L and the curved surface U1 on the right side L2 in the left-right direction L of the groove 40 of the gear grinding wheel T, respectively.
[0077] 7. Dressing method Next, the dressing method will be described mainly with reference to the flowcharts in Figures 13 to 17. However, the dressing method is not limited to the following description.
[0078] As shown in FIG. 13, the overall process of dressing includes a step S10 of acquiring point cloud data, a step S20 of calculating an evaluation function, a step S30 of determining whether the average evaluation function is minimum, a step S40 of determining a position correction amount, and a dressing step S50.
[0079] When S10 is executed, the control device 13 acquires point cloud data of the reference cross-sectional shape 51 of the reference rotary dresser 12a, and also acquires point cloud data of the actual cross-sectional shape 52 of the actual rotary dresser 12b.
[0080] Next, the control device 13 calculates an evaluation function in S20. A flowchart of the evaluation function calculation step S20 is shown in Fig. 14. The evaluation function calculation step S20 includes a step S21 of correcting the radial direction R, a step S22 of correcting the left-right direction L, and a step S23 of correcting the rotation angle θ.
[0081] When the evaluation function calculation step S20 is executed, in S21, the control device 13 calculates a radius difference, which is the difference between the radius at the outermost point of the reference cross-sectional shape 51 and the radius at the outermost point of the actual cross-sectional shape 52, in the radial direction R of the rotary dresser 12, and translates the actual cross-sectional shape 52 in the radial direction R so as to make the radius difference zero (see FIG. 5).
[0082] Next, in S22, the control device 13 executes an L direction correction step of calculating a position correction amount in the left-right direction L. Fig. 15 shows a flowchart of the L direction correction step S22.
[0083] When the L-direction correction step S22 is executed, the control device 13 executes the sum-of-squares calculation process S60 to calculate the first sum of squares SS1.
[0084] A flowchart of the sum-of-squares calculation process S60 is shown in Fig. 16. When the sum-of-squares calculation process S60 is executed, the control device 13 sets a point on the outer surface of the actual cross-sectional shape 52 as the distance calculation point 52a (S61).
[0085] Next, the control device 13 calculates a perpendicular bisector PL passing through the distance calculation point 52a from three consecutive points including the distance calculation point 52a and two points before and after the distance calculation point 52a (S62). However, if the distance calculation point 52a is the extreme point, the control device 13 calculates a perpendicular line to a line connecting the extreme point and a point adjacent to the extreme point.
[0086] Next, the control device 13 calculates the distance between the perpendicular bisector PL and all of the point cloud data of the reference cross-sectional shape 51 (S63). The control device 13 calculates two points from the point cloud data of the reference cross-sectional shape 51 that are the shortest distance from the perpendicular bisector PL (S64).
[0087] Next, the control device 13 calculates a straight line SL connecting the two points calculated from the point cloud data of the reference cross-sectional shape 51 (S64). The control device 13 calculates an intersection 51a between the calculated straight line SL and a perpendicular bisector PL calculated from the point cloud data of the actual cross-sectional shape 52 (S66). The control device 13 calculates a distance D between this intersection 51a and a distance calculation point 52a set in the point cloud data of the actual cross-sectional shape 52 (S67).
[0088] The control device 13 determines whether or not the above-described processing of S61 to S67 in Fig. 16 has been performed for all points on one surface (for example, the left L1 side) in the left-right direction L of the actual cross-sectional shape 52 (S68). If the processing of S61 to S67 in Fig. 16 has not been performed for all points on one surface (for example, the left L1 side) in the left-right direction L of the actual cross-sectional shape 52 (S68: N), the control device 13 repeats the processing of S61 to S67 in Fig. 16.
[0089] 16 has been performed for all points on one surface (for example, the left L1 side) in the left-right direction L of the actual cross-sectional shape 52 (S68: Y), the control device 13 calculates the distance D in S67 for all points on one surface (for example, the left L1 side) in the left-right direction L of the actual cross-sectional shape 52, and calculates the sum of squares of the distances D based on this distance D (S69). This completes the sum-of-squares calculation process S60.
[0090] Returning to FIG. 15, the control device 13 executes S222 to add or subtract a fixed value to the position of the actual cross-sectional shape 52 in the left-right direction L, thereby moving the actual cross-sectional shape 52 in the left-right direction L.
[0091] Next, the control device 13 executes a sum-of-squares calculation process S60 to calculate a second sum of squares SS2, which is the sum of squares of the distance D based on the actual cross-sectional shape 52 moved in the left-right direction L (S223). A redundant description of the sum-of-squares calculation process S60 will be omitted.
[0092] In S224, the control device 13 compares the first sum of squares SS1 with the second sum of squares SS2 to determine whether the first sum of squares SS1 is greater than the second sum of squares SS2. If the first sum of squares SS1 is greater than the second sum of squares SS2 (S224: Y), the control device 13 moves the actual cross-sectional shape 52 in the same direction as the direction in which the actual cross-sectional shape 52 was moved in the left-right direction L when calculating the second sum of squares SS2 in S222 (S225).
[0093] On the other hand, if the first sum of squares SS1 is smaller than the second sum of squares SS2 (S224: N), the control device 13 moves the actual cross-sectional shape 52 in the opposite direction to the direction in which the actual cross-sectional shape 52 was moved in the left-right direction L when calculating the second sum of squares SS2 in S222 (S226).
[0094] Next, the control device 13 determines whether the movement direction in the left-right direction L has changed continuously (S227). If the movement direction in the left-right direction L has not changed continuously (S227: N), the control device 13 repeats the processes of S221 to S226. On the other hand, if the movement direction in the left-right direction L has changed continuously (S227: Y), the control device 13 ends the L-direction correction step S22.
[0095] Returning to Fig. 14, the control device 13 executes the rotation angle θ correction step S23. Fig. 17 shows a flowchart of the rotation angle θ correction step S23.
[0096] When the rotation angle θ correction step S23 is executed, the control device 13 executes the sum of squares calculation process S60, using the rotation angle θ obtained when the actual cross-sectional shape 52 is rotated in the radial direction R about a rotation center (not shown) as a variable, while keeping the position of the actual cross-sectional shape 52 in the left-right direction L fixed, to calculate the first sum of squares SS1 (S231). The sum of squares calculation process S60 is the same as S60 in Fig. 16, so a duplicated description will be omitted.
[0097] Next, the control device 13 executes S232 to add or subtract a fixed value to the rotation angle θ of the actual cross-sectional shape 52, thereby moving the actual cross-sectional shape 52 in the clockwise direction θ1 or the counterclockwise direction θ2.
[0098] Next, the control device 13 executes a sum-of-squares calculation process S60 to calculate a second sum of squares SS2, which is the sum of squares of the distance D based on the actual cross-sectional shape 52 moved about the rotation angle θ (S233). The sum-of-squares calculation process S60 is the same as S60 in Fig. 16, and therefore a duplicated description will be omitted.
[0099] In S234, the control device 13 compares the first sum of squares SS1 with the second sum of squares SS2 to determine whether the first sum of squares SS1 is greater than the second sum of squares SS2. If the first sum of squares SS1 is greater than the second sum of squares SS2 (S234: Y), the control device 13 moves the actual cross-sectional shape 52 in the same direction as the direction in which the actual cross-sectional shape 52 was moved about the rotation angle θ when calculating the second sum of squares SS2 in S232 (S235).
[0100] On the other hand, if the first sum of squares SS1 is smaller than the second sum of squares SS2 (S234: N), the control device 13 moves the actual cross-sectional shape 52 in the opposite direction to the direction in which the actual cross-sectional shape 52 was moved about the rotation angle θ when calculating the second sum of squares SS2 in S232 (S236).
[0101] Next, the control device 13 determines whether the movement direction of the rotation angle θ has changed continuously for the rotation angle θ (S237). If the movement direction of the rotation angle θ has not changed continuously for the rotation angle θ (S237: N), the control device 13 repeats the processes of S231 to S236. On the other hand, if the movement direction of the rotation angle θ has changed continuously for the rotation angle θ (S237: Y), the control device 13 ends the rotation angle θ correction step S23.
[0102] Returning to Fig. 13, the control device 13 determines whether the calculated evaluation function is minimum (S30). The control device 13 compares the sum of squares of the distance D when the left-right direction L is changed, calculated in S22 of Fig. 14, with the sum of squares of the distance D when the rotation angle θ is changed, calculated in S23 of Fig. 14, and if the absolute value of the difference between the sum of squares of the distance D when the left-right direction L is changed and the sum of squares of the distance D when the rotation angle θ is changed is greater than a predetermined threshold, it determines that the sum of squares of the distance D has not converged and that the sum of squares of the distance D, which is the evaluation function, is not minimum (S30:N). In this case, the evaluation function calculation step S20 is repeated.
[0103] On the other hand, if the absolute value of the difference between the sum of squares of the distance D when the left-right direction L is changed and the sum of squares of the distance D when the rotation angle θ is changed is equal to or less than a predetermined threshold, it is determined that the sum of squares of the distance D, which is the evaluation function, has converged, and that the sum of squares of the distance D is minimum (S30: Y). In this case, the control device 13 determines the amount of position correction for the actual cross-sectional shape 52 (S40). That is, in S40, the control device 13 determines the amount of position correction based on the sum of squares for which it was determined in S30 that the fluctuation in the sum of squares has converged (the first sum of squares SS1 or the second sum of squares SS2). Because it was determined in S30 that the fluctuation between the first sum of squares SS1 and the second sum of squares SS2 has converged, the control device 13 may determine the amount of position correction based on either the first sum of squares SS1 or the second sum of squares SS2.
[0104] Next, the control device 13 uses the actual rotary dresser 12b to dress the side surface of the groove 40 of the gear grinding wheel T based on the position correction amount determined in S40 (S50). In this way, the side surface of the groove 40 of the gear grinding wheel T can be shaped.
[0105] 8. Effects of this form Next, the effects of this embodiment will be described. This embodiment is a method for forming a gear grinding wheel T having a groove 40, in which, assuming that a reference rotary dresser 12a having a reference cross-sectional shape 51 is used to form the side surface of the groove 40 of the gear grinding wheel T, a reference position of the reference rotary dresser 12a with respect to the groove 40 is obtained, an actual cross-sectional shape 52 of an actual rotary dresser 12b formed based on the reference rotary dresser 12a is obtained, and in a state in which the side surface of the groove 40 is formed using the actual rotary dresser 12b, a position correction amount of the actual rotary dresser 12b with respect to the reference position is calculated so that a position error between the actual cross-sectional shape 52 and the reference cross-sectional shape 51 is reduced, and the position correction amount is corrected with respect to the reference position, and the side surface of the groove 40 is formed using the actual rotary dresser 12b.
[0106] According to this embodiment, it is possible to reduce the positional error between the reference cross-sectional shape 51 of the reference rotary dresser 12a and the actual cross-sectional shape 52 of the actual rotary dresser 12b in the dressing process of the gear grinding wheel T. This makes it possible to improve the forming accuracy of the gear grinding wheel T.
[0107] Furthermore, according to this embodiment, even if the actual cross-sectional shape 52 of the actual rotary dresser 12b does not completely match the design shape, the gear grinding wheel T can be formed with high precision, similar to when it is formed using a rotary dresser formed to match the shape of the gear tooth flank. By grinding a gear using the gear grinding wheel T formed with such high precision, it becomes possible to grind the gear efficiently and accurately.
[0108] Furthermore, the position correction amount according to this embodiment includes at least the rotation correction amount of the actual rotary dresser 12b relative to the reference position, thereby reducing the position error regarding the rotation angle θ of the actual rotary dresser 12b.
[0109] Furthermore, the position correction amount according to this embodiment includes a linear correction amount for the two linear axes and a rotation correction amount. This makes it possible to reduce the position error in the axial direction of the two linear axes and the position error with respect to the rotation angle θ of the actual rotary dresser 12b. In this embodiment, the radial direction R and the left-right direction L are set as the axial directions of the two linear axes. Therefore, it is possible to reduce the position error of the actual rotary dresser 12b with respect to the radial direction R, the left-right direction L, and the rotation angle θ.
[0110] In this embodiment, the actual cross-sectional shape 52 is defined by a point group, an evaluation function relating to the position correction amount is calculated based on the point group, and the position correction amount is calculated so as to reduce the evaluation function, thereby improving the accuracy of the position correction amount.
[0111] Furthermore, according to this embodiment, an evaluation function is calculated based on the normal error between each point of the point cloud and the reference cross-sectional shape 51 in the normal direction of each point. As a result, in this embodiment, the actual cross-sectional shape 52 is defined by the point cloud, and a position correction amount is calculated so as to reduce the position error using the normal error between each point of the point cloud and the reference cross-sectional shape 51 in the normal direction of each point. This makes it possible to improve the accuracy of the position correction amount.
[0112] In this embodiment, the position correction amount has three variables. A first position correction amount related to one of the three variables is calculated, and with the first position correction amount fixed, second and third position correction amounts related to the remaining two variables are calculated. In this embodiment, the position correction amount in the radial direction R is calculated as the first position correction amount, and then the position correction amount in the left-right direction L and the position correction amount for the rotation angle θ are calculated. This allows the three variables related to the position correction amount to be calculated efficiently.
[0113] In this embodiment, the side surfaces of the grooves 40 of the gear grinding wheel T are formed one by one. This makes it possible to improve the forming accuracy of the side surfaces of the grooves 40.
[0114] The thickness dimension in the rotational axis direction of the actual rotary dresser 12b according to this embodiment is smaller than the across dimension of the groove 40 of the gear grinding wheel T. This makes it possible to prevent the rotary dresser 12 from interfering with the other surface of the groove 40 in the process of forming one surface of the groove 40.
[0115] This embodiment also provides a dressing device 30 for a gear grinding wheel T having grooves 40, and includes a grinding wheel support member 9 that supports the gear grinding wheel T rotatably about the Ct axis, a rotary dresser 12 that is rotatably supported about the Cd axis and shapes the side surfaces of the grooves 40 of the rotating gear grinding wheel T, and a control device 13 that moves at least one of the gear grinding wheel T and the rotary dresser 12 to a desired position and controls the rotation to shape the side surfaces of the grooves 40 of the gear grinding wheel T. Assuming that the side surface of the groove 40 of the gear grinding wheel T is formed using a reference rotary dresser 12a having a reference cross-sectional shape 51, the control device 13 acquires a reference position of the reference rotary dresser 12a with respect to the groove 40, acquires an actual cross-sectional shape 52 of the actual rotary dresser 12b formed based on the reference rotary dresser 12a, and in a state where the side surface of the groove 40 is formed using the actual rotary dresser 12b, calculates a position correction amount of the actual rotary dresser 12b with respect to the reference position so that a position error between the actual cross-sectional shape 52 and the reference cross-sectional shape 51 is reduced, corrects the position correction amount with respect to the reference position, and forms the side surface of the groove 40 using the actual rotary dresser 12b.
[0116] Furthermore, the gear grinding device 1 according to this embodiment is a gear grinding device 1 that grinds the tooth flank of a first gear 21 using a gear grinding wheel T formed by the above-described method for forming a gear grinding wheel T. The gear grinding device 1 includes a grinding wheel support member 9 that supports the gear grinding wheel T rotatably around the Ct axis, a workpiece support member 10 that supports the first gear 21 rotatably around the Cg axis, and a control device 13 that moves at least one of the gear grinding wheel T and the first gear 21 to a desired position and controls the rotation to grind the tooth flank of the first gear 21. According to this embodiment, the first gear 21 can be ground with high precision.
[0117] The present invention is not limited to the above-described embodiments, and can be applied to various embodiments within the scope of the present invention.
[0118] In this embodiment, the position correction amount is configured to include a linear correction amount for two linear axes and a rotation correction amount, but this is not limited to this, and the position correction amount may be configured to include only a linear correction amount for two linear axes.
[0119] In this embodiment, the position correction amount in the radial direction R is first determined and fixed, and the position correction amount in the left-right direction L and the position correction amount in the rotation angle θ are changed, but this is not limiting and any parameters can be changed. For example, the position correction amount may be calculated by changing the position correction amount in the radial direction R, the position correction amount in the left-right direction L, and the position correction amount in the rotation angle θ. [Explanation of symbols]
[0120] 1: gear grinding device, 9: grinding wheel support member, 10: workpiece support member, 11: rotary dresser support member, 12: rotary dresser, 12a: reference rotary dresser, 12b: actual rotary dresser, 13: control device, 14: storage device, 21: first gear, 30: dressing device, 40: groove, 51: reference cross-sectional shape, 52: actual cross-sectional shape, 52a: distance calculation point, Cg: axial direction of workpiece, Cd: axial direction of rotary dresser, Ct: grinding wheel axial direction, L: left-right direction, R: radial direction, T: gear grinding wheel, W: workpiece, θ: rotation angle, S10: point cloud data acquisition process, S20: evaluation function calculation process, S21: R direction correction process, S22: L direction correction process, S23: rotation angle θ correction process, S40: position correction amount determination process, S50: dressing process
Claims
1. A method for forming a grinding wheel having grooves, comprising the steps of: Acquire a reference position of a reference rotary dresser with respect to the groove, assuming that the side surface of the groove of the grinding wheel is formed using the reference rotary dresser having a reference cross-sectional shape; acquiring an actual cross-sectional shape of an actual rotary dresser formed based on the reference rotary dresser; calculating a positional correction amount of the actual rotary dresser relative to the reference position so as to reduce a positional error between the actual cross-sectional shape and the reference cross-sectional shape while forming the side surface of the groove using the actual rotary dresser; a grindstone shaping method, correcting the position correction amount with respect to the reference position and shaping the side surface of the groove using the actual rotary dresser;
2. 2. The method for shaping a grindstone according to claim 1, wherein the position correction amount includes at least a rotation correction amount of the actual rotary dresser relative to the reference position.
3. The position correction amount is The method for shaping a grindstone according to claim 1 , further comprising: a linear correction amount for two linear axes; and a rotation correction amount.
4. The actual cross-sectional shape is defined by a group of points; 2. The method for shaping a grindstone according to claim 1, further comprising the steps of: calculating an evaluation function relating to the amount of position correction based on the group of points; and calculating the amount of position correction so as to reduce the evaluation function.
5. 5. The method for shaping a grindstone according to claim 4, wherein the evaluation function is calculated based on a normal error between each point of the point cloud and the reference cross-sectional shape in a normal direction of the point.
6. The position correction amount has three variables: calculating a first position correction amount relating to one of the three variables; 2. The method for shaping a grindstone according to claim 1, wherein the second and third position correction amounts relating to the remaining two variables are calculated while the first position correction amount is kept constant.
7. The method for shaping a grindstone according to claim 1 , wherein shaping is performed on each side surface of the groove of the grindstone one by one.
8. 8. The method for shaping a grindstone according to claim 7, wherein a thickness dimension of the actual rotary dresser in the rotational axis direction is smaller than a cross dimension of the groove of the grindstone.
9. A molding device for a grinding wheel having grooves, a grindstone support member that supports the grindstone rotatably around a grindstone shaft; a rotary dresser that is rotatably supported around a rotary dresser shaft and shapes the side surface of the groove of the rotating grinding wheel; a control device that moves at least one of the grinding wheel and the rotary dresser to a desired position and controls the rotation thereof to shape the side surface of the groove of the grinding wheel; The control device Acquire a reference position of a reference rotary dresser with respect to the groove, assuming that the side surface of the groove of the grinding wheel is formed using the reference rotary dresser having a reference cross-sectional shape; acquiring an actual cross-sectional shape of an actual rotary dresser formed based on the reference rotary dresser; calculating a positional correction amount of the actual rotary dresser relative to the reference position so as to reduce a positional error between the actual cross-sectional shape and the reference cross-sectional shape while forming the side surface of the groove using the actual rotary dresser; a grindstone shaping device that corrects the position correction amount with respect to the reference position and shapes the side surface of the groove using the actual rotary dresser;
10. A gear grinding device that grinds a gear tooth surface using a grinding wheel formed by the grinding wheel molding method according to any one of claims 1 to 8, a grindstone support member that supports the grindstone rotatably around a grindstone shaft; a workpiece support member that supports the gear rotatably around the workpiece axis; a control device that moves at least one of the grinding wheel and the gear to a desired position and controls rotation to grind the tooth surface of the gear.
Citation Information
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Manufacture of thio, dithio or carbonyl group-containing organic compound
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