JP2026001642A - Grinding wheel forming method, grinding wheel forming device, and gear grinding device - Google Patents

Abstract

A grinding wheel forming method, a grinding wheel forming device, and a gear grinding device are provided that can improve the grinding wheel forming accuracy.
[Solution] A method for forming a gear grinding wheel T having a groove 40, assuming that a reference rotary dresser 12a having a reference cross-sectional shape 51 is used to form the side of the groove 40 of the gear grinding wheel T, the method includes: acquiring a reference position of the reference rotary dresser 12a relative to the groove 40; acquiring an actual cross-sectional shape 52 of an actual rotary dresser 12b formed based on the reference rotary dresser 12a; calculating a position correction amount for the actual rotary dresser 12b relative to the reference position so that the position error between the actual cross-sectional shape 52 and the reference cross-sectional shape 51 is small when the side of the groove 40 is formed using the actual rotary dresser 12b; correcting the position correction amount relative to the reference position; and forming the side of the groove 40 using the actual rotary dresser 12b.
[Selected Figure] Figure 11

Description

The present invention relates to a grinding wheel molding method, a grinding wheel molding device, and a gear grinding device.

Conventionally, in gear grinding machines that use threaded grinding wheels to machine various gears, the tooth flanks of the grinding wheels are modified by dressing to improve machining accuracy (see, for example, Patent Document 1). Dressing is performed, for example, using a disk-shaped rotary dresser. By using the rotary dresser to move along the side of the groove in the grinding wheel, 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 flanks of the gears.

Patent No. 6133131

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 and the actual shape of the rotary dresser may not match perfectly. If a rotary dresser with a shape that differs from the design shape is used, there is a risk that the grinding wheel's forming accuracy will decrease.

The present invention was made in consideration of these issues, and aims to provide a grinding wheel molding method, grinding wheel molding device, and gear grinding device that can improve the grinding wheel molding accuracy.

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.

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.

Yet another aspect of the present invention is
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.

According to one and other aspects of the present invention, 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 during the grinding wheel dressing process. This improves the grinding wheel forming accuracy.

Furthermore, according to yet another aspect of the present invention, gears can be ground with high precision using a grinding wheel.

As described above, the above aspects provide a grinding wheel molding method, a grinding wheel molding device, and a gear molding device that can improve the grinding wheel molding accuracy.

FIG. 1 is a front view showing a gear grinding device according to a first embodiment. 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. FIG. 1 is a diagram showing the cross-sectional shape of a gear grinding wheel according to a 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. 3A and 3B are diagrams showing a reference cross-sectional shape and an actual cross-sectional shape in the first embodiment; 1A and 1B are diagrams showing the 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 the state in which the correction has been made using one end of the radial direction R as a reference, and FIG. 1B shows the 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. FIG. 10 is a diagram showing a perpendicular bisector at a distance calculation point of an actual cross-sectional shape in the first embodiment. FIG. 10 is a diagram showing the intersection of a perpendicular bisector and a straight line in the reference cross-sectional shape in the first embodiment. 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. 10A to 10C are diagrams illustrating a process of correcting an actual cross-sectional shape with respect to a rotation angle θ in the first embodiment. 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. 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. 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 a state in which the gear grinding wheel is being shaped by the actual rotary dresser whose position has been corrected. 1 is a flowchart showing the overall steps of dressing in the first embodiment. 10 is a flowchart showing an evaluation function calculation process in the first embodiment. 10 is a flowchart showing an L-direction correction process in the first embodiment. 10 is a flowchart showing a sum-of-squares calculation process in the first embodiment. 10 is a flowchart showing a rotation angle θ correction process in the first embodiment.

(Embodiment 1)
1. Gear grinding device 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.

The gear grinding machine 1 comprises 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 top surface of the bed 2 and is 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 or a linear motor, etc.

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 gear grinding wheel T.

The Y-axis slide 5 is guided by a Y-axis guide 4 provided on the vertically extending side of the column 3, and is movable in the Y-axis direction (up and down) relative to the column 3. The rotating member 6 is provided on the Y-axis slide 5 and is rotatable around the A-axis, which is the horizontal axis. The rotating member 6 is rotatable within a range of 360°, for example.

The Z-axis slide 8 is guided by Z-axis guides 7, which are installed on the top surface of the bed 2 and perpendicular to the X-axis guides, and is movable in the Z-axis direction (horizontal direction) relative to the bed 2. Although not shown in detail, the Z-axis slide 8 is driven by a ball screw mechanism or linear motor, etc.

The grindstone support member 9 is attached to the rotating member 6 and rotates as the rotating member 6 rotates around axis A.

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 parallel to the Z axis. 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.

The workpiece support member 10 is mounted on the Z-axis slide 8 and supports the workpiece W rotatably around the Cg axis using the motor M1.

The rotary dresser support member 11 is mounted on the Z-axis slide 8 and supports the rotary dresser 12 so that it can rotate around the Cd axis using the motor M2.

The gear grinding machine 1 according to this embodiment is a six-axis machine, i.e., a machine with 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.

The gear grinding device 1 is configured so that the rotary dresser 12 can rotate around the Cd axis and move in the Z axis direction.

The control device 13 is configured, for example, by a CPU (Central Processing Unit), PLC (Programmable Logic Controller), or 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 synchronously rotating the first gear 21 and the gear grinding wheel T while controlling the relative positions of the first gear 21 and the gear grinding wheel T, so that the axial direction Cg of the first gear 21 (described below) and the grinding wheel axial direction Ct of the gear grinding wheel T form a predetermined crossing axis angle.

The control device 13 is also configured to rotate the gear grinding wheel T and the rotary dresser 12 synchronously and 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 in the gear grinding wheel T. The rotary dresser 12 in this embodiment is a forming device.

The storage device 14 can be a known storage device 14 such as RAM (Random Access Memory), ROM (Read Only Memory), a hard disk drive, or USB (Universal Serial Bus) memory. The storage device 14 may be located on the gear grinding machine 1, or may be a server connected via a network (not shown).

The feed direction of the gear grinding wheel T may be either along the central axis of the workpiece W or in the 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 in the direction in which the central axis of the workpiece W and the central axis of the gear grinding wheel T approach each other.

As shown in FIG. 1, the workpiece W in 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 and spaced apart 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 aligned parallel to each other.

In this embodiment, the gear grinding wheel T grinds the tooth flank of the first gear 21. However, the gear grinding wheel T may also 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.

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 that tapers from one end of the gear grinding wheel T to the other end (a cup shape).

3. Rotary dresser 12
The rotary dresser 12 is formed in a disk shape and is rotatably supported by a rotary dresser support member 11 so as to rotate about a Cd axis within a horizontal plane. The rotation axis of the rotary dresser 12 and the Cd axis are arranged coaxially.

As shown in Figure 1, the cutting edge 31 of the disk-shaped rotary dresser 12 has an acute-angled cross section, and one or both of the upper and lower surfaces are formed with contact portions 32 that come into contact with the side surfaces of the grooves 40 in the gear grinding wheel T. Figure 1 shows an example in which the contact portions 32 are formed on both the upper and lower surfaces. However, the contact portions 32 may also be formed on either the upper or lower surface of the rotary dresser 12. Diamond grains are uniformly attached to the entire surface of the cutting edge 31 and contact portions 32.

In this embodiment, the gear grinding wheel T is configured to move left and right (Z direction), front and rear (X direction), and up and down (Y direction) in FIG. 1, while the rotary dresser 12 is configured to move left and right (Z direction) in FIG. 1. This allows the rotary dresser 12 and the gear grinding wheel T to move relative to each other in the Z direction, and the rotary dresser 12 performs the desired dressing on the side surfaces of the grooves 40 in the gear grinding wheel T.

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.

4-1. Regarding the gear grinding wheel T Figure 2(a) shows a portion of the cross-sectional shape of the gear grinding wheel T. The gear grinding wheel T has a groove 40. The side surface of the groove 40 is formed by the rotary dresser 12. A curved surface S1 is formed on the inner side surface of the groove 40, on the left side L1 in the left-right direction L in Figure 2(a). The curved surface S1 is indicated by a thick solid line. One end of the curved surface S1 in the radial direction R in Figure 2(a) is connected to the bottom surface of the groove 40. The other end of the curved surface S1 in the radial direction R in Figure 2(a) is connected to point A1. The groove 40 opens downward in the radial direction R in Figure 2(a) at point A1.

4-2. Regarding the Reference Rotary Dresser 12a In order to form the side surface of the groove 40 of the gear grinding wheel T into a desired shape, a reference rotary dresser 12a having a reference cross-sectional shape 51 of the rotary dresser 12 is designed. 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 obtained by transferring at least a portion of the shape of the side surface of the groove 40 of the first gear 21. When the rotary dresser 12 having the reference cross-sectional shape 51 is set as the reference rotary dresser 12a, the position of the reference rotary dresser 12a relative to the groove 40 when 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 is defined as the reference position.

The shape of the reference rotary dresser 12a in 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. Simultaneous forming of both side surfaces of the groove 40 of the gear grinding wheel T using the rotary dresser 12 is preferable, as it improves the efficiency of the gear grinding wheel T forming process. However, as mentioned above, the shape of the 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 will 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 reference rotary dresser 12a in 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.

The reference rotary dresser 12a has a cutting edge 31a at its tip in the radial direction R. The reference rotary dresser 12a shown in Figure 2(b) has a contact portion 32a on the left side L1 of the cutting edge 31a in the left-right direction L in Figure 2(b). One end of the contact portion 32a in the radial direction R is connected to the cutting edge 31a. The other end of the contact portion 32a in the radial direction R is connected to point A2. The portion of the reference rotary dresser 12a below point A2 in the radial direction R in Figure 2(b) is formed in a flat shape.

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 Figure 3). The curved surface S2 is indicated by a thick solid line.

Figure 2(c) shows a portion of the actual cross-sectional shape 52, which is the cross-sectional shape of the 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 shown in Figure 2(c) has a contact portion 32b on the left L1 side of the cutting edge 31b in the left-right direction L in Figure 2(c). One end of the contact portion 32b in the radial direction R is connected to the cutting edge 31b. The other end of the contact portion 32b in the radial direction R is connected to point A3. The portion of the actual rotary dresser 12b below point A3 in the radial direction R in Figure 2(c) is formed in a flat shape.

Of the contact portion 32b of the actual rotary dresser 12b, the curved surface S3 on the left side L1 in the left-right direction L comes into contact with the curved surface S1 of the groove 40 of the gear grinding wheel T, forming the curved surface S1. The curved surface S3 is indicated by a thick solid line.

As shown in Figures 2(b) and 2(c), the reference cross-sectional shape 51 of the reference rotary dresser 12a, which is the design shape, may not completely match the actual cross-sectional shape 52 of the actual rotary dresser 12b that is actually formed.

4-3. Regarding the Cross-sectional Shapes of the Gear Grinding Wheel T, the Reference Rotary Dresser 12a, and the Actual Rotary Dresser 12b Fig. 3 shows the state in which the left end and point A1 in Fig. 2(a) of the cross-sectional shape of the gear grinding wheel T, the left end and point A2 in Fig. 2(b) of the reference cross-sectional shape 51 of the reference rotary dresser 12a, and the left end and point A3 in Fig. 2(c) of the actual cross-sectional shape 52 of the actual rotary dresser 12b are aligned. Below, 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 will be described. 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.

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 considering 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 prevented. Note that the left-right direction L in FIG. 2 is an example of two linear axes.

As shown in FIG. 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 to prevent the actual rotary dresser 12b from interfering with portions of the side of the groove 40 of the gear grinding wheel T that are different from the side of the object to be ground, when taking into consideration correcting the position of the actual rotary dresser 12b when dressing the side of the groove 40 of the gear grinding wheel T with the actual rotary dresser 12b.

As shown in FIG. 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 also be smaller than the width dimension of the reference rotary dresser 12a in the left-right direction L in FIG. 3.

If an actual rotary dresser 12b having an actual cross-sectional shape 52 different from the reference cross-sectional shape 51 were used to form the side surface of the groove 40 of the gear grinding wheel T at the reference position described above, it would be difficult to form the cross-sectional shape of the gear grinding wheel T into the designed shape.

In this embodiment, as described below, when the actual rotary dresser 12b is used to form the side surface of the groove 40 of the gear grinding wheel, the position correction amount of the actual rotary dresser 12b relative to the reference position is calculated so as to reduce the position error between the actual cross-sectional shape 52 and the reference cross-sectional shape 51, and the position correction amount is corrected relative to the reference position, and the actual rotary dresser 12b is used to form the side surface of the groove 40.

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.

(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 may be, for example, a contact method using a probe or a non-contact method using laser light. 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.

In Figure 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 for the reference cross-sectional shape 51, six points on the surface on the left side L1 in the left-right direction L in Figure 4 (corresponding to the curved surface S2) are representatively shown by filled-in symbols, and six points on the surface on the left side L1 (corresponding to the curved surface S3) of the point cloud data for the actual cross-sectional shape 52 are representatively shown by filled-in symbols. The same applies to Figures 5 to 10.

(2) Next, the control device 13 calculates an evaluation function related to the position correction amount based on the point cloud.

The parameters used to calculate the evaluation function are not particularly limited. For example, any parameter can be used, such as the radial dimension R, the left-right dimension L, or the rotation angle θ of the actual rotary dresser 12b (described below).

The evaluation function is not particularly limited, and may be calculated, for example, based on the distance D (an example of normal error) between each point in the normal direction of each point in the point cloud and the reference cross-sectional shape 51 described below. 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.

(3) Next, the control device 13 calculates the amount of position correction so that the evaluation function becomes smaller. There are no particular limitations on the method for calculating the amount of position correction so that the evaluation function becomes smaller, and any method can be used. In this embodiment, for example, the amount of position correction can be calculated so that the evaluation function becomes smaller as shown in (4) to (14) below.

(4) The control device 13 calculates the 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 that the radius difference becomes zero. The radial direction R is an example of two linear axes.

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 in parallel 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 points P2 and P3. Also, as shown in FIG. 4, a configuration may be adopted in which point A2 on the reference cross-sectional shape 51 and point A3 on the actual cross-sectional shape 52 are translated in parallel so that the radius difference becomes zero. In this case, the rotation center of the rotation angle θ can be points A2 and A3.

(5) Next, as shown in FIG. 6, the control device 13 sets a point on the outer surface of the actual cross-sectional shape 52 as the distance calculation point 52a. The control device 13 calculates a perpendicular bisector PL (an example of a normal line) 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. However, if the distance calculation point 52a is the extreme end point, the control device 13 calculates a perpendicular line (an example of a normal line) to the straight line connecting the extreme end point.

(6) The control device 13 calculates the distance (an example of 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.

(7) As shown in FIG. 7, the control device 13 calculates the intersection 51a between the straight line SL connecting two points calculated from the point cloud data of the reference cross-sectional shape 51 and the perpendicular bisector PL calculated from the point cloud data of the actual cross-sectional shape 52. The control device 13 calculates the distance D between this intersection 51a and the distance calculation point 52a set in the point cloud data of the actual cross-sectional shape 52.

(8) The control device 13 performs the above-described processes (5) to (7) for all points on the left side L1 of the actual cross-sectional shape 52 in the left-right direction L. As a result, the control device 13 calculates the distance D described in (5) above for all points on the left side L1 of the actual cross-sectional shape 52 in the left-right direction L, 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 the first sum of squares SS1.

(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 moved is also arbitrary, and may be a fixed amount, random, or a fixed amount that takes momentum into account. The control device 13 performs the processes (5) to (8) described above 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 the second sum of squares SS2.

(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.

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 direction opposite 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.

However, the control device 13 may also 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 to move the actual cross-sectional shape 52 to the left L1 or right L2 in the left-right direction L depending on whether the random number is odd or even, or it may be determined in advance whether to move the actual cross-sectional shape 52 to the left L1 or right L2 if the first sum of squares SS1 and the second sum of squares SS2 are the same.

(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, it temporarily terminates the calculation of the position in the left-right direction L. A case in which the direction of movement in the left-right direction L changes continuously is, for example, when the actual cross-sectional shape 52 is moved to the left L1 in the left-right direction L, and then in the next trial, the actual cross-sectional shape 52 is moved to the right L2 in the left-right direction L. Similarly, a case in which the direction of movement in the left-right direction L changes continuously is also when the cross-sectional shape is moved to the right L2 in the left-right direction L, and then in the next trial, the actual cross-sectional shape 52 is moved to the left L1 in the left-right direction L.

(12) Next, the control device 13 executes the processes (5) to (11) described above, using 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 as a variable. In detail, in the descriptions of (5) to (11) described above, 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 Figure 9, and the right side of the left-right direction L is read as the counterclockwise direction θ2 of the rotation angle θ in Figure 9. Other than the above, the description is the same as the descriptions of (5) to (11), so redundant explanations will be omitted.

(13) When the processing related to the rotation angle θ is completed, the control device 13 again alternately executes the above-described processing (5) to (10) related to the left-right direction L and the above-described processing (11) related to the rotation angle θ. However, either the processing related to the left-right direction L or the processing related to the rotation angle θ may be executed first.

(14) The control device 13 terminates 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 condition that the fluctuations in the sum of squares calculated as the evaluation function have converged, or may determine that the evaluation function is minimum when other conditions are met.

For example, if 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 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 may be calculated, and if this average value is smaller than a predetermined threshold, it may be determined that the sum of squares has converged.

The control device 13 may also calculate the smallest sum of squares of 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.

In this manner, as shown in FIG. 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 relative 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.

However, the position correction amount relative to the reference position may also be calculated by a computer (not shown) separate from the gear grinding device 1, and the calculated position correction amount may be transmitted to the control device 13.

6. Grinding Wheel Total Forming Method Based on the position correction amount calculated in 5. above, the actual rotary dresser 12b is used to form the side surfaces of the grooves 40 of 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 grooves 40 of the gear grinding wheel T, thereby forming the curved surface S1 on the left side L1 in the left-right direction L of the grooves 40 of the gear grinding wheel T. In this way, the side surfaces of the grooves 40 of the gear grinding wheel T can be formed with high precision using the actual rotary dresser 12b.

As shown in FIG. 12(a), the position correction amount may be calculated for 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, the curved surface U2 on the right side L2 in the left-right direction L of the reference rotary dresser 12a, and the curved surface U3 on the right side L2 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 side L1 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 side L2 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 side L2 in the left-right direction L of the actual rotary dresser 12b.

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. Alternatively, one actual rotary dresser 12b may be used to calculate the position correction amount only for the curved surface S3 on the left side L1 in the left-right direction L, and another actual rotary dresser 12b may be used to calculate the position correction amount only for the curved surface U3 on the right side L2 in the left-right direction L, 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.

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.

As shown in Figure 13, the overall dressing process includes step S10 of acquiring point cloud data, step S20 of calculating an evaluation function, step S30 of determining whether the average evaluation function is minimum, step S40 of determining the position correction amount, and step S50 of dressing.

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 point cloud data of the actual cross-sectional shape 52 of the actual rotary dresser 12b.

Next, in S20, the control device 13 calculates an evaluation function. Figure 14 shows a flowchart of the evaluation function calculation process S20. The evaluation function calculation process S20 includes a process S21 for correcting the radial direction R, a process S22 for correcting the left-right direction L, and a process S23 for correcting the rotation angle θ.

When the evaluation function calculation step S20 is executed, in S21, the control device 13 calculates the 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 that the radius difference becomes zero (see Figure 5).

Next, in S22, the control device 13 executes an L direction correction process to calculate the position correction amount in the left-right direction L. Figure 15 shows a flowchart of the L direction correction process S22.

When the L-direction correction process S22 is executed, the control device 13 executes the sum-of-squares calculation process S60 to calculate the first sum-of-squares SS1.

Figure 16 shows a flowchart of the sum-of-squares calculation process S60. 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).

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 this 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 the straight line connecting the extreme point and the point adjacent to this extreme point.

Next, the control device 13 calculates the distance between the perpendicular bisector PL and all point cloud data of the reference cross-sectional shape 51 (S63). The control device 13 calculates the 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).

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 the intersection 51a between the calculated straight line SL and the perpendicular bisector PL calculated from the point cloud data of the actual cross-sectional shape 52 (S66). The control device 13 calculates the distance D between this intersection 51a and the distance calculation point 52a set in the point cloud data of the actual cross-sectional shape 52 (S67).

The control device 13 determines whether the processes of S61 to S67 in FIG. 16 described above have been performed for all points on one surface of the actual cross-sectional shape 52 in the left-right direction L (e.g., the left L1 side) (S68). If the processes of S61 to S67 in FIG. 16 have not been performed for all points on one surface of the actual cross-sectional shape 52 in the left-right direction L (e.g., the left L1 side) (S68: N), the control device 13 repeats the processes of S61 to S67 in FIG. 16.

On the other hand, if the processes of S61 to S67 in FIG. 16 have been performed for all points on one side of the actual cross-sectional shape 52 in the left-right direction L (for example, the left L1 side) (S68: Y), the control device 13 calculates the distance D in S67 for all points on one side of the actual cross-sectional shape 52 in the left-right direction L (for example, the left L1 side), 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.

Returning to FIG. 15, the control device 13 executes S222, adds or subtracts a fixed value to the position of the actual cross-sectional shape 52 in the left-right direction L, and moves the actual cross-sectional shape 52 in the left-right direction L.

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 explanation of the sum-of-squares calculation process S60 will be omitted.

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 in the left-right direction L as the actual cross-sectional shape 52 was moved in when calculating the second sum of squares SS2 in S222 (S225).

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 direction opposite 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).

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.

Returning to Figure 14, the control device 13 executes the rotation angle θ correction process S23. Figure 17 shows a flowchart of the rotation angle θ correction process S23.

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 radial direction R of the actual cross-sectional shape 52 is rotated around 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 Figure 16, so a redundant description will be omitted.

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 counterclockwise direction θ2.

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, so a redundant description will be omitted.

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).

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 direction opposite 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).

Next, the control device 13 determines whether the direction of movement of the rotation angle θ has changed continuously for the rotation angle θ (S237). If the direction of movement 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 direction of movement 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 process S23.

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 distance D when the left-right direction L is changed, calculated in S22 of FIG. 14, with the sum of squares of distance D when the rotation angle θ is changed, calculated in S23 of FIG. 14. If the absolute value of the difference between the sum of squares of distance D when the left-right direction L is changed and the sum of squares of distance D when the rotation angle θ is changed, is greater than a predetermined threshold, the control device 13 determines that the sum of squares of distance D has not converged and that the sum of squares of distance D, which is the evaluation function, is not minimum (S30: N). In this case, the evaluation function calculation step S20 is repeated.

On the other hand, if the absolute value of the difference between the sum of squares of distance D when the left-right direction L is changed and the sum of squares of 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 distance D has converged, and that the sum of squares of distance D, which is the evaluation function, is at a minimum (S30: Y). In this case, the control device 13 determines the position correction amount for the actual cross-sectional shape 52 (S40). That is, in S40, the control device 13 determines the position correction amount 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 position correction amount based on either the first sum of squares SS1 or the second sum of squares SS2.

Next, the control device 13 uses the actual rotary dresser 12b to dress the side surface of the groove 40 in 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 in the gear grinding wheel T can be shaped.

8. Effects of the Present Embodiment Next, the effects of the present 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 as to reduce a position error between the actual cross-sectional shape 52 and the reference cross-sectional shape 51, 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.

According to this embodiment, the position 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 can be reduced during the dressing process of the gear grinding wheel T. This improves the forming accuracy of the gear grinding wheel T.

Furthermore, according to this embodiment, even if the actual cross-sectional shape 52 of the actual rotary dresser 12b does not perfectly 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 gears using a gear grinding wheel T formed with such high precision, it is possible to grind gears efficiently and accurately.

In addition, the position correction amount in this embodiment includes at least the rotation correction amount of the actual rotary dresser 12b relative to the reference position. This reduces the position error regarding the rotation angle θ of the actual rotary dresser 12b.

In addition, the position correction amounts in this embodiment include linear correction amounts for the two linear axes and rotational correction amounts. This makes it possible to reduce the position error in the axial directions 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 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.

In this embodiment, the actual cross-sectional shape 52 is defined by a point cloud, an evaluation function related to the position correction amount is calculated based on the point cloud, and the position correction amount is calculated so as to reduce the evaluation function. This improves the accuracy of the position correction amount.

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 the normal error between each point of the point cloud and the reference cross-sectional shape 51 in the normal direction of each point is used to calculate the position correction amount so as to reduce the position error. This makes it possible to improve the accuracy of the position correction amount.

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 while the first position correction amount is held constant, a second position correction amount and a third position correction amount 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 a position correction amount in the left-right direction L and a 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.

In this embodiment, the side surfaces of the grooves 40 of the gear grinding wheel T are shaped one side at a time. This improves the shaping accuracy of the side surfaces of the grooves 40.

The thickness dimension in the rotational axis direction of the actual rotary dresser 12b in this embodiment is smaller than the across dimension of the groove 40 in the gear grinding wheel T. This prevents the rotary dresser 12 from interfering with the other surface of the groove 40 during the process of forming one surface of the groove 40.

In addition, this embodiment is a dressing device 30 for a gear grinding wheel T having a groove 40, and includes a grinding wheel support member 9 that rotatably supports the gear grinding wheel T around the Ct axis, a rotary dresser 12 that is rotatably supported around the Cd axis and shapes the side surfaces of the groove 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 groove 40 of the gear grinding wheel T. Assuming that the side surface of a groove 40 in a gear grinding wheel T is formed using a reference rotary dresser 12a having a reference cross-sectional shape 51, the control device 13 acquires the reference position of the reference rotary dresser 12a relative to the groove 40, acquires the actual cross-sectional shape 52 of the actual rotary dresser 12b formed based on the reference rotary dresser 12a, and, in a state in which the side surface of the groove 40 is formed using the actual rotary dresser 12b, calculates a position correction amount for the actual rotary dresser 12b relative to the reference position so as to reduce the position error between the actual cross-sectional shape 52 and the reference cross-sectional shape 51, corrects the position correction amount relative to the reference position, and forms the side surface of the groove 40 using the actual rotary dresser 12b.

The gear grinding device 1 according to this embodiment 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 rotatably supports the gear grinding wheel T about the Ct axis, a workpiece support member 10 that rotatably supports the first gear 21 about 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 its 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.

The present invention is not limited to the above-described embodiments, and can be applied to various embodiments without departing from the spirit of the present invention.

In this embodiment, the position correction amount is configured to include a linear correction amount for two linear axes and a rotational 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.

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 for the rotation angle θ are varied, but this is not limited to this, and any parameters can be varied. For example, the position correction amount may be calculated by varying the position correction amount in the radial direction R, the position correction amount in the left-right direction L, and the position correction amount for the rotation angle θ.

1: Gear grinding machine, 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: Workpiece axial direction, Cd: Rotary dresser axial direction, 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 (10)

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; The grinding wheel shaping method 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. 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. 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. The grinding wheel shaping method according to claim 4, wherein the evaluation function is calculated based on the normal error between each point of the point cloud and the reference cross-sectional shape in the normal direction of the point. 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. The grinding wheel shaping method according to claim 1, wherein shaping is performed on each side of the groove of the grinding wheel. The grinding wheel shaping method according to claim 7, wherein the thickness dimension of the actual rotary dresser in the rotational axis direction is smaller than the cross dimension of the groove of the grinding wheel. 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; 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.