Dressing device, gear grinding device, and dressing method for grinding wheel

Abstract

This dressing device is provided with: a dressing mechanism capable of performing dressing on the grinding groove of a grindstone having a spirally continuous grinding groove; and a control unit for controlling the operation of the dressing mechanism. The control unit: controls the grindstone to rotate about the grindstone rotation axis and controls a dressing tool to rotate about the tool rotation axis, thereby using a pair of dressing surfaces to perform dressing on two adjacent grinding surfaces in the groove width direction; and controls a tool turning part to turn the dressing tool about the tool turning axis, thereby changing the angles of the pair of the dressing surfaces with respect to the two grinding surfaces.

Description

Technical Field

[0001] The present invention relates to a dressing device, a gear grinding device, and a dressing method for a grinding wheel.

Background Art

[0002] Gears are required to have high machining accuracy depending on their intended use. Gears that require high machining accuracy are manufactured by finishing the rough workpiece by grinding with a grinding wheel. As the gears to be manufactured, for example, there are helical gears in which the teeth are formed in a spiral shape so as to be inclined with respect to the central axis. Further, as a gear processing method, crowning processing may be performed on the tooth surface such that the center of the tooth in the tooth trace direction bulges. When crowning processing is performed on the teeth of a helical gear, since the teeth are formed in a spiral shape and the pressure angle of the tooth surface changes in the tooth trace direction, the tooth surface becomes twisted. In order to manufacture a gear with an appropriately adjusted degree of tooth surface twist (bias amount), for example, a grinding wheel whose pressure angle changes in the tooth trace direction is used.

[0003] For example, Patent Document 1 discloses the configuration of a dressing device for dressing a screw-shaped grinding wheel. The screw-shaped grinding wheel is continuous in a spiral shape and has grinding grooves for grinding the teeth of a gear. The dressing device relatively moves and brings into contact a screw-shaped grinding wheel, which is the object of dressing, and a dressing tool while rotating them relative to each other. In the configuration disclosed in Patent Document 1, at least one of the screw-shaped grinding wheel and the dressing tool is moved at a constant speed in the axial direction, for example, and the rotational speed of the screw-shaped grinding wheel is changed, whereby dressing is performed on the grinding grooves of the screw-shaped grinding wheel such that the pressure angle changes in the tooth trace direction.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, dressing in the dressing device as described above needs to be performed on two grinding surfaces adjacent to each other in the groove width direction in the grinding groove of the screw-shaped grinding wheel. In the case of a grinding groove having a complex shape in which the pressure angle changes in the tooth flank direction, it is difficult to perform dressing so as to change the pressure angle simultaneously for two grinding surfaces adjacent to each other in the groove width direction. For this reason, there is a method in which a dressing tool is applied separately to the grinding surface on the first side and the grinding surface on the second side in the groove width direction of the grinding groove, and dressing is performed for each grinding surface. However, in such a method, dressing takes time and labor, and improvement is desired in terms of work efficiency.

[0006] The present invention provides a dressing device, a gear grinding device, and a method for dressing a grinding wheel that can perform dressing efficiently and in a short time even for a grinding wheel having a grinding surface with a complex shape.

Means for Solving the Problems

[0007] In order to solve the above problems, a dressing device according to the present disclosure is configured to be relatively movable in a first direction orthogonal to a grindstone rotation axis with respect to a grindstone having grinding grooves continuously formed in a spiral shape around the grindstone rotation axis, and includes a dressing mechanism capable of dressing the grinding grooves, and a control unit configured to control the operation of the dressing mechanism. The dressing mechanism includes a disk-shaped dressing tool having a pair of dressing surfaces at its tip end that are capable of dressing two adjacent grinding surfaces in a groove width direction, which are surfaces constituting the grinding grooves, and a tool turning unit configured to turn the dressing tool around a tool turning axis orthogonal to the tool rotation axis and the first direction. The control unit rotates the grindstone around the grindstone rotation axis, rotates the dressing tool around the tool rotation axis to dress two adjacent grinding surfaces in the groove width direction with the pair of dressing surfaces, and turns the dressing tool around the tool turning axis by the tool turning unit to change the angle of the pair of dressing surfaces with respect to the two grinding surfaces. When grinding one tooth of the gear, the spiral grinding groove has a first part that contacts a first end on one side of the tooth in the tooth flanks direction of the tooth, and a second part that contacts a second end on the other side of the tooth in the tooth flanks direction. In a cross-section including the grinding wheel rotation axis, at the first part, the control unit inclines the dressing tool so that the tip is located on the first side in the groove width direction with respect to the groove center axis located in the middle of the grinding groove in the groove width direction; and in a cross-section including the grinding wheel rotation axis, at the second part, the control unit inclines the dressing tool so that the tip is located on the second side in the groove width direction with respect to the groove center axis. 。

[0008] A gear grinding apparatus according to the present disclosure includes a worktable configured to rotatably support a workpiece to be a gear, a grindstone configured to grind the workpiece, a grindstone support unit configured to rotationally drive the grindstone around the grindstone rotation axis, and the dressing device as described above.

[0009] A method for dressing a grindstone according to the present disclosure is a method for dressing a grindstone in the dressing device as described above, and includes a step of rotating the grindstone around the grindstone rotation axis, a step of rotationally driving the dressing tool around the tool rotation axis, a step of dressing two adjacent grinding surfaces in the groove width direction with the pair of dressing surfaces, and a step of changing the angle of the pair of dressing surfaces with respect to the two grinding surfaces by turning the dressing tool around the tool turning axis by the tool turning unit.

Advantages of the Invention

[0010] According to the dressing device, gear grinding device, and grinding wheel dressing method of the present disclosure, even for a grinding wheel having a grinding surface with a complex shape, it is possible to perform dressing efficiently and in a short time.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Mode for Carrying Out the Invention

[0012] (First Embodiment) Hereinafter, with reference to the accompanying drawings, embodiments for implementing a dressing device, a gear grinding device, and a dressing method for a grinding wheel according to the present disclosure will be described. However, the present disclosure is not limited to only these embodiments.

[0013] (Configuration of Gear Grinding Device) The gear grinding device 1A shown in FIGS. 1 and 2 is capable of grinding a workpiece W to be a gear 200 with a grinding wheel T. In the gear grinding device 1A, the workpiece W is ground by bringing the grinding wheel T and the workpiece W into contact with each other while rotating synchronously. The workpiece W is, for example, a member to be processed formed in a disk shape or a cylindrical shape. The workpiece W forms teeth 201 formed on the outer peripheral surface by the grinding wheel T.

[0014] As shown in FIG. 3, the grinding wheel T is formed in a cylindrical shape centered on the grinding wheel rotation axis O4. On the outer peripheral surface of the grinding wheel T, grinding grooves 101 corresponding to the tooth profile of a desired gear are formed. The grinding grooves 101 are formed so as to continuously spiral around the grinding wheel rotation axis O4 with respect to the outer peripheral surface of the grinding wheel T. The grinding grooves 101 are formed so as to be sandwiched by the grinding teeth 100 which are convex portions. The grinding grooves 101 are constituted by two grinding surfaces 101A and 101B (a first grinding surface 101A and a second grinding surface 101B) adjacent to each other in the groove width direction Dw which is the direction in which the grinding wheel rotation axis O4 extends. The two grinding surfaces 101A and 101B face each other in the groove width direction Dw. That is, the two grinding surfaces 101A and 101B are the surfaces inside one grinding groove 101. The two grinding surfaces 101A and 101B are the surfaces that come into contact with the workpiece W during machining of the workpiece W by the grinding wheel T, and are the surfaces that form the teeth 201 of the gear 200 after the workpiece W is ground.

[0015] In this embodiment, the gear 200 manufactured by grinding the workpiece W with the grinding wheel T is, for example, a helical gear in which the teeth 201 are formed in a spiral shape so as to be inclined with respect to the central axis of the gear 200. As shown in FIG. 4, in this embodiment, the teeth 201 of the gear 200 to be manufactured are subjected to crowning processing so that the tooth surface bulges between the first end 201a on one side (first side) in the tooth trace direction Ds and the second end 201b on the other side (second side) in the tooth trace direction Ds. Here, the tooth trace direction Ds is a direction orthogonal to the direction in which the teeth 201 arranged apart from each other are lined up, and is a direction in which the tooth surface extends including the direction in which the central axis of the gear extends. That is, the tooth trace direction Ds is the direction in which a virtual line connecting the first end 201a and the second end 201b extends. In the case of a helical gear, the tooth trace direction Ds is a direction that extends in a spiral shape with respect to the central axis of the gear 200. As shown in FIG. 3, when grinding one tooth 201 of the gear 200 with the grinding wheel T, the grinding wheel T is rotated around the grinding wheel rotation axis O4, and the grinding groove 101 is pressed against the region of the workpiece W that will become the tooth 201. In the direction in which the grinding groove 101 extends, after the first part 101s of the grinding groove 101 hits the first end 201a on one side in the tooth trace direction Ds of the tooth 201, when the grinding wheel T is rotated while grinding the tooth 201 with the grinding groove 101, the second part 101t of the grinding groove 101 hits the second end 201b on the other side in the tooth trace direction Ds of the tooth 201. That is, using the continuous region from the first part 101s to the second part 101t of the grinding groove 101, the first end 201a to the second end 201b of one tooth 201 are continuously ground.

[0016] In the grinding groove 101, the first part 101s and the second part 101t are regions at different positions in the direction in which the grinding groove 101 extends and the direction in which the grinding wheel axis O4 extends. For example, when the grinding wheel T is a single - groove grinding wheel, when viewing the grinding wheel T from a direction perpendicular to the grinding wheel axis O4, the first part 101s and the second part 101t are adjacent positions in the direction in which the grinding wheel axis O4 extends (the starting position and the ending position of one revolution of the grinding groove 101). Also, when the grinding wheel T is a double - groove grinding wheel, when viewing the grinding wheel T from a direction perpendicular to the grinding wheel axis O4, the first part 101s and the second part 101t are positions separated by one grinding groove 101 in the direction in which the grinding wheel axis O4 extends (the starting position and the ending position of one revolution of the grinding groove 101). Therefore, the positions of the first part 101s and the second part 101t shown in FIG. 3 are only examples and can be appropriately changed according to the shape of the gear 200 to be manufactured.

[0017] As shown in FIG. 5, when the gear 200 is a helical gear, when crowning is performed on the tooth surface of the tooth 201, twisting of the tooth profile, so - called bias, may occur. The twisting (bias) of the tooth profile means that the inclination direction (increasing or decreasing direction) of the angle of the tooth surface at the tooth root and the tooth tip in the tooth profile direction Dg is different (opposite) between the first end 201a on one side and the second end 201b on the other side in the tooth flank direction Ds. In the present embodiment, in order to suppress the degree of twist (bias amount) of the tooth surface, the pressure angle of the grinding groove 101 of the grinding wheel T for grinding the tooth 201 is formed to change along the tooth flank direction Ds.

[0018] As shown in FIGS. 1 and 2, the gear grinding apparatus 1A includes a bed 2, a work table 3, a grinding wheel support portion 4, a dressing device 5A, a tailstock 6, a tailstock support portion 7, a dressing device moving portion 55, a tailstock moving portion 65, and a control portion 9.

[0019] The bed 2 is a pedestal installed on the floor surface as shown in FIG. 1. The work table 3, the grinding wheel support portion 4, and the tailstock support portion 7 are attached to the bed 2.

[0020] The worktable 3 rotatably supports the work W on the bed 2. The worktable 3 is attached to the bed 2 at a position where the work W can be faced to the grinding wheel T. The worktable 3 is rotatable with respect to the bed 2 about a table axis O3 extending in the vertical direction Dv.

[0021] The grinding wheel support portion 4 rotationally drives the grinding wheel T for grinding the work W around the grinding wheel rotation axis O4. The grinding wheel support portion 4 movably supports the grinding wheel T with respect to the worktable 3 on the bed 2. As shown in FIG. 2, the grinding wheel support portion 4 has a grinding wheel support portion main body 41, a grinding wheel moving portion 42, and a grinding wheel driving portion 43.

[0022] The grinding wheel support portion main body 41 is disposed apart from the worktable 3 on the bed 2. The grinding wheel support portion main body 41 is movable in the horizontal direction with respect to the worktable 3 with the grinding wheel T. Here, the moving direction of the grinding wheel support portion main body 41 with respect to the bed 2 is referred to as the first direction D1. The first direction D1 is one of the horizontal directions and is the longitudinal direction of the bed 2. Therefore, the grinding wheel support portion main body 41 adjusts the position of the grinding wheel T in the first direction D1 with respect to the worktable 3.

[0023] As shown in FIG. 1, the grinding wheel moving portion 42 is movable in the vertical direction Dv with respect to the grinding wheel support portion main body 41. Therefore, the grinding wheel moving portion 42 adjusts the position of the grinding wheel T in the vertical direction Dv with respect to the worktable 3.

[0024] As shown in Fig. 2, the grindstone driving unit 43 is movable in a horizontal direction (referred to as the second direction D2) orthogonal to the first direction D1 with respect to the grindstone moving unit 42. The second direction D2 is a direction orthogonal to the first direction D1 and the vertical direction Dv, and is the width direction of the bed 2. The grindstone T is detachably attached to the grindstone driving unit 43. The grindstone driving unit 43 moves the grindstone T while rotating it about a grindstone rotation axis O4 extending in a direction intersecting the first direction D1 by the power of a driving source such as a motor. Therefore, the grindstone driving unit 43 adjusts the position of the grindstone T in the second direction D2 with respect to the worktable 3 while rotating the grindstone T.

[0025] As shown in Figs. 1 and 2, the dressing device 5A is composed of a dressing mechanism 50 capable of dressing the grindstone T and a part of the control unit 9. The dressing mechanism 50 is supported by the tailstock support portion 7 so as to be movable in the vertical direction Dv via the dressing device moving portion 55. The dressing mechanism 50 will be described later.

[0026] The tailstock support portion 7 supports the tailstock 6 and the dressing mechanism 50 so as to be movable in the vertical direction Dv. The tailstock support portion 7 is disposed at a position separated from the grindstone support portion 4 in the first direction D1 with the worktable 3 interposed therebetween.

[0027] The tailstock 6 presses the work W supported by the worktable 3 toward the worktable 3 from above in the vertical direction Dv.

[0028] The tailstock support portion 7 includes a support portion main body 71, a first guide rail 75, and a second guide rail 76. The support portion main body 71 is fixed to the bed 2. The support portion main body 71 has a portal shape in which a conveyance path through which the work W can pass is formed inside. The first guide rail 75 and the second guide rail 76 are fixed to the surface of the support portion main body 71 facing the grindstone support portion 4.

[0029] The first guide rail 75 is fixed to the support portion main body 71. The first guide rail 75 extends linearly in the vertical direction Dv. The pair of first guide rails 75 are arranged at a distance from the support portion main body 71 in the second direction D2.

[0030] The second guide rail 76 is fixed to the support portion main body 71. The second guide rail 76 extends linearly in the vertical direction Dv. The pair of second guide rails 76 are arranged at a distance from the support portion main body 71 in the second direction D2. The pair of second guide rails 76 are arranged so as to sandwich the pair of first guide rails 75 inside in the second direction D2.

[0031] The tailstock moving portion 65 supports the tailstock 6 so as to be movable toward the work table 3. The tailstock moving portion 65 is movably supported by the first guide rail 75. The tailstock 6 is fixed to the tailstock moving portion 65. The tailstock moving portion 65 is moved relative to the first guide rail 75 by a driving device such as a motor (not shown). That is, the tailstock moving portion 65 moves the tailstock 6 only in the vertical direction Dv with respect to the tailstock support portion 7 along the first guide rail 75.

[0032] The work rotation and transfer unit 8 rotates around the work rotation axis between the work processing position and the work exchange position to move the work W. Here, the work processing position is a position where the work W can be placed on the work table 3. Therefore, at the work processing position, the work W is ground by the grinding wheel T. Also, the work exchange position is a position where the processed work W can be exchanged with the unprocessed work W. The work exchange position is a position on the opposite side of the grinding wheel support portion 4 across the tailstock support portion 7. That is, the work exchange position is in the same position in the vertical direction Dv and the second direction D2 with respect to the work processing position, and is a position separated in the first direction D1. The work rotation and transfer unit 8 moves the work W located at the work processing position and the work W located at the work exchange position relative to each other during the exchange. Note that the work rotation and transfer unit 8 is moved to a position where there is no interference with the grinding of the work W by the grinding wheel T except during the exchange of the work W.

[0033] As shown in FIGS. 1 and 6, the dressing device moving unit 55 supports the dressing mechanism 50 so as to be movable in the first direction D1. The dressing device moving unit 55 is supported by the second guide rail 76 so as to be movable in the vertical direction Dv. The dressing device moving unit 55 linearly moves the dressing mechanism 50 between the dressing device standby position P1 (see FIG. 1) and the dressing device use position P2 (see FIG. 6). The dressing device use position P2 is a position where the grinding wheel T can be dressed. That is, the dressing device use position P2 is a position where the dressing tool 51A contacts the grinding wheel T. The dressing device standby position P1 is above the dressing device use position P2 in the vertical direction Dv, and is a position where the dressing tool 51A cannot contact the grinding wheel T.

[0034] Also, the dressing device moving unit 55 has a structure that does not interfere with the tailstock moving unit 65 when viewed from above in the vertical direction Dv. For this reason, when the dressing device moving unit 55 or the tailstock moving unit 65 moves in the vertical direction Dv, they do not interfere with each other. The dressing device moving unit 55 is moved relative to the second guide rail 76 by a driving device such as a motor (not shown).

[0035] When viewed from above in the vertical direction Dv, the dressing device 5A is disposed at a position closer to the grindstone support portion 4 than the tailstock 6.

[0036] (Dressing mechanism) The dressing mechanism 50 is configured such that the grindstone support portion main body 41 is movable horizontally with respect to the work table 3 with respect to the grindstone T, and thus is relatively movable in the first direction D1 with respect to the grindstone T. The dressing mechanism 50 is capable of dressing the grinding grooves 101 of the grindstone T such that the pressure angle changes along the tooth flank direction Ds. As shown in FIGS. 6 and 7, the dressing mechanism 50 includes a dressing tool 51A, a tool rotating portion 52, and a tool turning portion 53.

[0037] The dressing tool 51A is formed in a disk shape that spreads around the tool rotation axis O5. The tool rotation axis O5 extends along the grindstone rotation axis O4. That is, the tool rotation axis O5 is not limited to extending parallel to the grindstone rotation axis O4, and may extend intersecting to such an extent that they are not orthogonal. The tool rotation axis O5 of the present embodiment extends parallel to the grindstone rotation axis O4. The dressing tool 51A is formed in a disk shape with a through hole formed in the center and tapering toward the tip (outer peripheral end). The dressing tool 51A is fixed to the rotation shaft 54 in a state where the rotation shaft 54 of the tool rotation unit 52 described later is inserted through the central through hole. That is, the dressing tool 51A is arranged so as to spread outward in the radial direction Dr with respect to the rotation shaft 54. Thereby, the dressing tool 51A is rotatably supported around the tool rotation axis O5 integrally with the rotation shaft 54. The dressing tool 51A of the present embodiment integrally has a dressing portion 510 that forms the tip and an annular tool body portion 500 arranged on the inner side Dri in the radial direction Dr with respect to the dressing portion 510. On both side surfaces in the rotation axis direction Da, which is the direction in which the grindstone rotation axis O4 extends, a pair of dressing surfaces 511 and 512 (first dressing surface 511 and second dressing surface 512) are formed on the dressing portion 510. The pair of dressing surfaces 511 and 512 are capable of dressing two adjacent grinding surfaces 101A and 101B in the groove width direction Dw. The rotation axis direction Da is the groove width direction Dw when dressing is performed. The pair of dressing surfaces 511 and 512 of the present embodiment face opposite sides (outer sides) so as not to face each other in the rotation axis direction Da. The pair of dressing surfaces 511 and 512 are formed in a tapered shape such that the interval in the rotation axis direction Da gradually decreases in a cross-sectional view including the tool rotation axis O5 from the inner side Dri to the outer side Dro in the radial direction Dr. That is, due to the pair of dressing surfaces 511 and 512, the thickness of the dressing portion 510 becomes thinner as it approaches the tip away from the rotation shaft 54.

[0038] The tool rotating unit 52 has a motor that rotationally drives the rotating shaft 54 around the tool rotation axis line O5. The rotating shaft 54 is formed in a columnar shape centered on the tool rotation axis line O5. The tool rotating unit 52 is fixed to the dressing device moving unit 55.

[0039] The tool turning unit 53 rotationally drives the dressing tool 51A around the tool turning axis line O6 that is orthogonal to the tool rotation axis line O5 and the first direction D1. The tool turning axis line O6 of the present embodiment extends in the vertical direction Dv. The tool turning unit 53 is fixed to the dressing device moving unit 55. As shown in FIGS. 7 to 9, the tool turning unit 53 rotationally drives the dressing tool 51A around the tool turning axis line O6 together with the tool rotating unit 52. By turning around the tool turning axis line O6, the dressing tool 51A can be swung so that the tip where the dressing portion 510 is formed swings in the rotation axis direction Da (groove width direction Dw). Specifically, the pair of dressing surfaces 511 and 512 are swung so as to rotate from a state where the tool center axis Ct is orthogonal to the grinding wheel rotation axis line O4. The tool center axis Ct is a virtual axis passing through the center of the dressing portion 510 so as to extend at an equal distance from the pair of dressing surfaces 511 and 512 in the rotation axis direction Da in a cross section including the tool rotation axis line O5.

[0040] When dressing the grinding wheel T, the dressing tool 51A is rotationally driven around the tool rotation axis line O5 in a state where the dressing portion 510 is inserted into the grinding groove 101. Thereby, the two grinding surfaces 101A and 101B adjacent to each other in the groove width direction Dw in the grinding groove 101 are simultaneously contacted by the pair of dressing surfaces 511 and 512.

[0041] As shown in FIG. 1, the control unit 9 controls various mechanisms in the gear grinding apparatus 1A when machining the workpiece W with the grinding wheel T or when dressing the grinding wheel T with the dressing mechanism 50. The control unit 9 of the present embodiment controls the operations of the worktable 3, the grinding wheel support portion 4, the dressing device 5A, the tailstock 6, the dressing device moving unit 55, and the tailstock moving unit 65.

[0042] (Hardware Configuration Diagram) As shown in FIG. 10, the control unit 9 is a computer including a CPU 81 (Central Processing Unit), a ROM 82 (Read Only Memory), a RAM 83 (Random Access Memory), an HDD 84 (Hard Disk Drive), and a signal transmission module 85. The signal transmission module 85 transmits control signals to each part of the gear grinding device 1A.

[0043] (Functional Block Diagram) As shown in FIG. 11, the control unit 9 controls each part of the gear grinding device 1A by executing a program stored in advance in the device itself via the ROM 82, the RAM 83, and the HDD 84 by the CPU 81.

[0044] The control unit 9 functions as a part of the dressing device 5A and controls the operations of other parts when dressing the grinding wheel T. The control unit 9 controls the dressing device moving part 55 and moves the dressing mechanism 50 to the dressing device use position P2 so that the dressing tool 51A contacts the grinding wheel T. The control unit 9 controls at least one of the grinding wheel support part main body 41 and the dressing device moving part 55 to move in the first direction D1 and presses the grinding wheel T against the dressing tool 51A. Further, the control unit 9 controls the grinding wheel T to rotate around the grinding wheel rotation axis O4 and the dressing tool 51A to be rotationally driven around the tool rotation axis O5. Thereby, the control unit 9 inserts the rotating dressing part 510 into the grinding groove 101 of the rotating grinding wheel T. After that, the control unit 9 simultaneously presses the pair of dressing surfaces 511 and 512 against the adjacent grinding surfaces 101A and 101B in the groove width direction Dw. Thereby, dressing is simultaneously performed on the two grinding surfaces 101A and 101B by the pair of dressing surfaces 511 and 512. The control unit 9 dresses along the tooth direction Ds of the grinding groove 101 while turning the dressing tool 51A around the tool turning axis O6. As a result, dressing is performed while the angles of the pair of dressing surfaces 511 and 512 with respect to the two grinding surfaces 101A and 101B change.

[0045] Furthermore, when dressing is performed with the dressing tool 51A, the control unit 9 gradually rotates the dressing tool 51A around the tool rotation axis O6 as it approaches from the first part 101s to the second part 101t of the grinding groove 101. Thereby, dressing is performed such that the pressure angle (the angle between the pair of grinding surfaces 101A and 101B with respect to the groove center axis Cm as shown in FIG. 7 described later) of the grinding groove 101 gradually changes along the tooth flank direction Ds.

[0046] As a configuration when performing dressing, the control unit 9 of the present embodiment includes configurations of a grindstone control unit 91, a tool rotation control unit 92, a tool turning control unit 93, and an output unit 94.

[0047] The grindstone control unit 91 controls the grindstone support unit 4. Specifically, the grindstone control unit 91 moves the grindstone support unit main body 41 and the grindstone moving unit 42. Further, the grindstone control unit 91 rotates the grindstone T around the grindstone rotation axis O4 by the grindstone drive unit 43. Furthermore, the grindstone control unit 91 presses the rotated grindstone T against the dressing tool 51A. Thereafter, with the dressing tool 51A pressed against it, the grindstone T is sent in the second direction D2.

[0048] The tool rotation control unit 92 controls the tool rotation unit 52. The tool rotation control unit 92 rotationally drives the rotation shaft 54. The tool rotation control unit 92 of the present embodiment rotates the dressing tool 51A around the tool rotation axis O5 at a constant speed. Note that the tool rotation control unit 92 may rotate the dressing tool 51A at an arbitrary rotation speed so as to change the rotation speed.

[0049] The tool rotation control unit 93 controls the tool rotation unit 53. The tool rotation control unit 93 rotates the dressing tool 51A around the tool rotation axis O6 by an arbitrary rotation amount (rotation angle) in the tool rotation unit 53. In the present embodiment, the tool rotation control unit 93 rotates the dressing tool 51A by a constant rotation amount. Further, the tool rotation control unit 93 linearly and gradually changes the angles of the first dressing surface 511 with respect to the first grinding surface 101A and the second dressing surface 512 with respect to the second grinding surface 101B in the process of dressing from the first part 101s to the second part 101t of the grinding groove 101.

[0050] Specifically, as shown in FIG. 8, in the first part 101s, the tool rotation control unit 93 inclines the dressing tool 51A so that the angle between the tool center axis Ct and the groove center axis Cm becomes the inclination angle θ1 with the tip positioned on the first side Dw1 in the groove width direction Dw with respect to the groove center axis Cm. Here, the groove center axis Cm is a virtual axis located in the middle of the grinding groove in the groove width direction Dw in the cross section including the grinding wheel rotation axis O4. That is, in the cross section including the grinding wheel rotation axis O4, the distance between the groove center axis Cm and the first grinding surface 101A and the distance between the groove center axis Cm and the second grinding surface 101B are equal. As shown in FIG. 9, in the second part 101t, the tool rotation control unit 93 inclines the dressing tool 51A so that the angle between the tool center axis Ct and the groove center axis Cm becomes the inclination angle θ2 with the tip positioned on the second side Dw2 in the groove width direction Dw with respect to the groove center axis Cm. Here, the inclination angle θ1 and the inclination angle θ2 may have the same absolute value or different absolute values. Further, as shown in FIG. 7, in the intermediate part 101c between the first part 101s and the second part 101t, the dressing tool 51A is not inclined with respect to the groove center axis Cm, and the tool center axis Ct and the groove center axis Cm are in a parallel state (coincident state).

[0051] The output unit 94 outputs a control signal to various devices. The output unit 94 is a signal transmission module 85 in terms of hardware.

[0052] (Procedure of the grinding wheel dressing method) The dressing method S1 of the grinding wheel T is a method of dressing the grinding wheel T for grinding the gear 200. As shown in FIG. 12, the dressing method S1 of the grinding wheel T according to the embodiment of the present disclosure includes a preparation step S2, a step S3 of rotating the grinding wheel T, a step S4 of rotationally driving the dressing tool 51A, and a step S5 of dressing the grinding groove 101 while swinging the dressing tool 51A.

[0053] In the preparation step S2, the control unit 9 controls the dressing device moving unit 55 to move the dressing device 5A to the dressing device use position P2. Further, if necessary, the control unit 9 controls the dressing device moving unit 55 and the grinding wheel moving unit 42 to adjust the position of the grinding wheel T with the dressing tool 51A and the grinding wheel moving unit 42.

[0054] In the step S3 of rotating the grinding wheel T, the grinding wheel control unit 91 rotates the grinding wheel T around the grinding wheel rotation axis O4 by the grinding wheel driving unit 43.

[0055] In the step S4 of rotationally driving the dressing tool 51A, the tool rotation control unit 92 rotationally drives the dressing tool 51A around the tool rotation axis O5 together with the rotation axis 54 by the tool rotation unit 52.

[0056] In the step S5 of dressing the grinding groove 101, first, at least one of the grinding wheel support body 41 and the dressing device moving unit 55 is moved in the first direction D1. Thereby, the dressing portion 510 of the rotating dressing tool 51A is inserted into the grinding groove 101 of the grinding wheel T, and the pair of dressing surfaces 511 and 512 are pressed against the two grinding surfaces 101A and 101B. Then, the grinding wheel T against which the dressing tool 51A is pressed is sent in the second direction D2 in a state of rotating around the grinding wheel rotation axis O4. In this way, while the rotating dressing tool 51A is pressed against the grinding groove 101, the grinding wheel T rotates around the grinding wheel rotation axis O4, so that the pair of dressing surfaces 511 and 512 simultaneously and continuously dress the pair of grinding surfaces 101A and 101B in the direction in which the grinding groove 101 extends.

[0057] In this step S5, as shown in FIGS. 8 and 9, while dressing the pair of grinding surfaces 101A and 101B simultaneously in the direction in which the dressing groove 101 extends by the dressing tool 51A, the dressing tool 51A is rotated around the tool rotation axis O6. As a result, the dressing tool 51A rotates so that the angle between the tool center axis Ct and the groove center axis Cm gradually changes.

[0058] Specifically, for example, in the direction in which the dressing groove 101 extends, the dressing tool 51A is rotated by a certain rotation amount between the spaced-apart first portion 101s and the second portion 101t. That is, the dressing tool 51A is rotated so that the rotation amount is linear. As a result, as shown in FIG. 8, when the contact portion between the grinding wheel T and the dressing tool 51A is at the first portion 101s, the dressing tool 51A is inclined at an inclination angle θ1 so that the tip is positioned on the first side Dw1 in the groove width direction Dw with respect to the groove center axis Cm. Thereby, the angle of the first dressing surface 511 with respect to the first grinding surface 101A is widened to be an obtuse angle, and the angle of the second dressing surface 512 with respect to the second grinding surface 101B is narrowed to be an acute angle.

[0059] After that, in the intermediate portion 101c where the contact portion between the grinding wheel T and the dressing tool 51A is on the way from the first portion 101s toward the second portion 101t, as shown in FIG. 7, the dressing tool 51A is in a state where the tool center axis Ct coincides with the groove center axis Cm (a state where the inclination angle is 0°).

[0060] Furthermore, after that, when the contact portion between the grinding wheel T and the dressing tool 51A advances from the intermediate portion 101c and reaches the second portion 101t, as shown in FIG. 9, the dressing tool 51A is inclined at an inclination angle θ2 so that the tip is positioned on the second side Dw2 in the groove width direction Dw with respect to the groove center axis Cm. Thereby, the angle of the first dressing surface 511 with respect to the first grinding surface 101A is narrowed to be an acute angle, and the angle of the second dressing surface 512 with respect to the second grinding surface 101B is widened to be an obtuse angle.

[0061] In addition, in the present embodiment, when the contact portion between the grinding wheel T and the dressing tool 51A reaches the second portion 101t from the first portion 101s through the intermediate portion 101c, the dressing tool 51A rotates so that the tool center axis Ct with respect to the groove center axis Cm changes linearly.

[0062] As described above, the inclination angles θ1 and θ2 when the dressing tool 51A is inclined most around the tool rotation axis line O6 are preferably set to values suitable for bias correction machining for eliminating, for example, the twist bias of the tooth surface that occurs when crowning is applied in the tooth trace direction Ds of the helical gear. Specifically, the twist of the tooth profile generated on the tooth surface when the tooth 201 of the gear 200 is actually ground with the grinding wheel T having the grinding groove 101 dressed without inclining the dressing tool 51A is measured. Based on the measurement results, the inclination angles θ1 and θ2 are set so as to cancel the degree of twist (bias amount) of the tooth surface, which is the deviation of the pressure angle in the tooth trace direction Ds on the tooth surface.

[0063] (Operational effects) The dressing device 5A with the above configuration rotates the dressing tool 51A around the tool rotation axis O6 while simultaneously dressing two grinding surfaces 101A and 101B adjacent to each other in the groove width direction Dw of the grinding groove 101 with a pair of dressing surfaces 511 and 512 of the dressing tool 51A. Thereby, the contact angles of the pair of dressing surfaces 511 and 512 with respect to the two grinding surfaces 101A and 101B can be adjusted simultaneously. Specifically, by rotating the dressing tool 51A, the first dressing surface 511 tilts with respect to the first grinding surface 101A. At the same time, the second dressing surface 512 tilts with respect to the second grinding surface 101B so as to face the opposite direction to the tilt of the first dressing surface 511 with respect to the first grinding surface 101A. That is, the contact angle of the first dressing surface 511 with respect to the first grinding surface 101A and the contact angle of the second dressing surface 512 with respect to the second grinding surface 101B change simultaneously so that they have the same absolute value and opposite signs. Thereby, dressing can be performed so as to simultaneously change the pressure angles of the two grinding surfaces 101A and 101B. Thereby, when correcting the bias, the dressing of the grinding groove 101 can be efficiently performed.

[0064] Also, when performing dressing, as the dressing tool 51A gradually rotates as it approaches from the first part 101s to the second part 101t of the grinding groove 101. As a result, the pressure angles of the two grinding surfaces 101A and 101B gradually change along the tooth flank direction Ds from the first part 101s to the second part 101t of the grinding groove 101. Therefore, when machining the gear 200 in the grinding groove 101, the pressure angle can be smoothly adjusted from the first part 101s that contacts one end 201a on one side in the tooth flank direction Ds of the tooth 201 to the second part 101t that contacts the second end 201b of the tooth 201.

[0065] Further, the dressing tool rotates such that the tips of the first part 101s and the second part 101t face in opposite directions in the groove width direction Dw with respect to the groove center axis Cm. As a result, the pressure angles of the first part 101s and the second part 101t can be adjusted while making the change amount of the pressure angle at the intermediate part 101c between the first part 101s and the second part 101t approach zero. From this, for example, the pressure angle at the first part 101s can be gradually changed to be larger than the pressure angle at the intermediate part, and the pressure angle at the second part 101t can be gradually changed to be smaller than the pressure angle at the intermediate part. Conversely, the pressure angle at the first part 101s can be gradually changed to be smaller than the pressure angle at the intermediate part, and the pressure angle at the second part 101t can be gradually changed to be larger than the pressure angle at the intermediate part.

[0066] When one dressing part 510 is inserted into the grinding groove 101 of the grinding wheel T, a pair of dressing surfaces 511 and 512 come into contact with two adjacent grinding surfaces 101A and 101B in the groove width direction Dw of the grinding groove 101. As a result, dressing can be simultaneously performed on both surfaces of the grinding groove 101 in the groove width direction Dw.

[0067] Also, since the dressing device 5A as described above is provided in the gear grinding devices 1A and 1B, dressing can be efficiently performed on the grinding wheel T used for grinding the gear 200.

[0068] (Modification of the First Embodiment) In the above first embodiment, the dressing tool 51A is formed in a disk shape that tapers. That is, in the first embodiment, the dressing tool 51A has a structure in which a pair of dressing surfaces 511 and 512 are formed in one dressing part 510. However, the shape of the dressing tool is not limited to such a structure.

[0069] For example, as shown in FIG. 13, the dressing tool 51B of the modified example is formed in a disk shape with a concave portion formed at the end such that the tip is bifurcated. Specifically, the dressing tool 51B of the modified example includes a first dressing portion 520 and a second dressing portion 530.

[0070] The first dressing portion 520 extends from the tool main body portion 500 to the outside Dro in the radial direction Dr. The second dressing portion 530 extends from the tool main body portion 500 to the outside Dro in the radial direction Dr at a position away from the first dressing portion 520. The second dressing portion 530 is arranged at an interval on the first side Da1 in the rotation axis direction Da with respect to the first dressing portion 520. On the first side Da1 in the rotation axis direction Da of the first dressing portion 520, a first dressing surface 521 is formed. On the second side Da2 in the rotation axis direction Da of the second dressing portion 530, a second dressing surface 531 is formed.

[0071] The first dressing surface 521 polishes the first grinding surface 101C on the first side Da1 in the rotation axis direction Da of the grinding groove 101. The second dressing surface 531 polishes the second grinding surface 101D on the second side Da2 in the rotation axis direction Da of the adjacent grinding groove 101 arranged on the first side Da1 in the rotation axis direction Da with respect to the grinding groove 101 having the first grinding surface 101C. That is, the first dressing surface 521 and the second dressing surface 531 do not simultaneously process both surfaces of one grinding groove 101, but simultaneously process one by one of two adjacent grinding grooves 101. In this way, the first dressing surface 521 and the second dressing surface 531 are capable of simultaneously dressing two adjacent grinding surfaces 101C and 101D in the groove width direction Dw. Thereby, the dressing tool 51A of the first embodiment dresses the grinding wheel T with the dressing portion 510 inserted into the grinding groove 101, while the dressing tool 51B of the modified example dresses the grinding wheel T with the convex portion between two adjacent grinding grooves 101 sandwiched by the first dressing portion 520 and the second dressing portion 530.

[0072] Further, the dressing tool 51B is formed to fit into a convex portion formed between two grinding grooves 101 where the first dressing portion 520 and the second dressing portion 530 are adjacent to each other. That is, the tip surfaces 522 of the first dressing portion 520 and 532 of the second dressing portion 530 are capable of polishing the groove bottom surface 101b of the grinding groove 101. The base surface 540 between the first dressing portion 520 and the second dressing portion 530 is capable of polishing the tip surface 101d of the grinding groove 101.

[0073] (Function and effect) Also in such a dressing tool 51B, similar to the above embodiment, while simultaneously dressing two grinding surfaces 101C and 101D adjacent to each other in the groove width direction Dw in the convex portion forming the grinding groove 101 with a pair of dressing surfaces 521 and 531 of the dressing tool 51B, the dressing tool 51B is rotated around the tool rotation axis O6. Thereby, the contact angles of the pair of dressing surfaces 521 and 531 with respect to the two grinding surfaces 101C and 101D can be adjusted simultaneously.

[0074] Further, in the dressing tool 51B, the groove bottom surface 101b and the tip surface 101d of the grinding groove 101 can be simultaneously dressed by the tip surfaces 522, 532, and the base surface 540. That is, with the first dressing portion 520 and the second dressing portion 530 having a shape adapted to the grinding groove 101, the grinding groove 101 can be machined with many contact surfaces as if in surface contact. Thereby, the dressing time of the grinding groove 101 can be shortened and it can be performed more efficiently.

[0075] (Second Embodiment) Next, a second embodiment of the dressing device and the gear grinding device according to the present disclosure will be described. In the second embodiment described below, components common to the first embodiment are denoted by the same reference numerals in the drawings and their description is omitted. The second embodiment is different from the first embodiment in that the lead of the grinding groove 101 of the grinding wheel T is changed.

[0076] As shown in FIG. 14, in the dressing device 5B and the gear grinding device 1B of the present embodiment, the lead dimension L of the spiral grinding groove 101 is non-uniform in the rotation axis direction Da. The lead dimension L is the length of the grinding groove 101 in the groove width direction Dw when the grinding wheel T rotates a predetermined number of times. Specifically, when the grinding wheel T is a single-rib grinding wheel, it is the length in the groove width direction Dw in a cross section including the grinding wheel rotation axis O4 of the start point and the end point of the grinding groove 101 when the grinding wheel T makes one revolution. Further, when the grinding wheel T is a double-rib grinding wheel, it is the length in the groove width direction Dw in a cross section including the grinding wheel rotation axis O4 of the start point and the end point with one grinding groove 101 in between when the grinding wheel T makes one revolution.

[0077] In the present embodiment, the lead dimension L of the grinding groove 101 is not constant from the first part 101s to the second part 101t of the grinding groove 101, but gradually changes. For example, the lead dimension L of the grinding groove 101 is the largest L1 on one side in the groove width direction Dw, and gradually decreases to L2 and L3 as it goes toward the other side of the groove width direction Dw. At this time, the lead dimension L preferably changes linearly.

[0078] To change the lead dimension L, for example, there is a method of keeping the moving speed of the grinding wheel T in the second direction D2 by the grinding wheel driving unit 43 constant and changing the rotation speed of the dressing tool 51A by the tool rotating unit 52. When the lead dimension L is gradually decreased from one side to the other side in the groove width direction Dw, the pressure angle of the grinding groove 101 gradually increases from one side to the other side in the groove width direction Dw. Note that the method of changing the lead dimension L is not limited to such a method. That is, as long as the lead dimension L can be changed, the grinding wheel T and the dressing tool 51A may be moved and rotated under any conditions.

[0079] (Function and Effect) When the lead dimension L of the grinding groove 101 is changed and a pair of dressing surfaces 511 and 512 are simultaneously applied to the two grinding surfaces 101A and 101B for dressing, the angles at which the pair of dressing surfaces 511 and 512 contact the two grinding surfaces 101A and 101B can be adjusted simultaneously. Specifically, since the lead dimension L of the grinding groove 101 is changing, the position (depth) at which the first dressing surface 511 contacts the first grinding surface 101A and the position (depth) at which the second dressing surface 512 contacts the second grinding surface 101B will shift by the same amount in the same direction in the groove width direction Dw. As a result, the angle at which the first dressing surface 511 contacts the first grinding surface 101A and the angle at which the second dressing surface 512 contacts the second grinding surface 101B will change simultaneously such that they have the same absolute value and the same sign. Thereby, dressing can be performed by changing the pressure angles of the two grinding surfaces 101A and 101B simultaneously by the same amount in the same direction. Therefore, by changing the lead dimension L while rotating the dressing tool 51A, dressing can be performed such that the pressure angles of the two grinding surfaces 101A and 101B are changed while being finely adjusted simultaneously. Thereby, when correcting the bias, dressing of the grinding groove 101 can be performed more efficiently.

[0080] Also, by changing the lead dimension L from the first part 101s toward the second part 101t in the tooth flank direction Ds, in addition to adjusting the pressure angle by rotating the dressing tool 51A, the pressure angle can be further finely adjusted in the tooth flank direction Ds by changing the lead dimension L. Thereby, even when the degree of change in the pressure angle from the first part 101s toward the second part 101t is different between the grinding surface 101A on one side of the groove width direction Dw and the grinding surface 101B on the other side, it becomes possible to appropriately adjust the pressure angle.

[0081] As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, each configuration and their combinations in each embodiment are merely examples, and additions, omissions, substitutions, and other changes to the configuration are possible without departing from the spirit of the present invention. Further, the present invention is not limited by the embodiments and is limited only by the claims.

[0082] <Addendum> The dressing apparatuses 5A and 5B, the gear grinding apparatuses 1A and 1B, and the dressing method S1 of the grinding wheel T described in each embodiment are understood as follows, for example.

[0083] (1) The dressing devices 5A and 5B according to the first aspect are relatively movable in a first direction D1 orthogonal to the grinding wheel rotation axis O4 with respect to a grinding wheel T having grinding grooves 101 continuously spiraling around the grinding wheel rotation axis O4, and include a dressing mechanism 50 capable of dressing the grinding grooves 101 and a control unit 9 for controlling the operation of the dressing mechanism 50. The dressing mechanism 50 is rotationally driven around a tool rotation axis O5 extending along the grinding wheel rotation axis O4, and has a pair of dressing surfaces 511, 512, 521, 531 at the tip for dressing two adjacent grinding surfaces 101A, 101B, 101C, 101D in the groove width direction Dw, which are the surfaces constituting the grinding grooves 101, on a disk-shaped dressing tool 51A, 51B. The dressing mechanism 50 further includes a tool turning unit 53 for turning the dressing tools 51A, 51B around a tool turning axis O6 orthogonal to the tool rotation axis O5 and the first direction D1. The control unit 9 rotates the grinding wheel T around the grinding wheel rotation axis O4, rotates the dressing tools 51A, 51B around the tool rotation axis O5, dresses two adjacent grinding surfaces 101A, 101B, 101C, 101D in the groove width direction Dw with the pair of dressing surfaces 511, 512, 521, 531 of the dressing tools 51A, 51B, and changes the angles of the pair of dressing surfaces 511, 512, 521, 531 with respect to the two grinding surfaces 101A, 101B, 101C, 101D by turning the dressing tools 51A, 51B around the tool turning axis O6 by the tool turning unit 53.

[0084] The contact angles of the pair of dressing surfaces 511 and 512 with respect to the two grinding surfaces 101A and 101B can be adjusted simultaneously. Specifically, by rotating the dressing tool 51A, one of the dressing surfaces 511 inclines with respect to one of the grinding surfaces 101A. At the same time, the other dressing surface 512 inclines with respect to the other grinding surface 101B so as to face the opposite direction to the inclination of one of the dressing surfaces 511 with respect to one of the grinding surfaces 101A. That is, the contact angle of one of the dressing surfaces 511 with respect to one of the grinding surfaces 101A and the contact angle of the other dressing surface 512 with respect to the other grinding surface 101B change simultaneously such that they have the same absolute value but opposite signs. Thereby, dressing can be performed so as to simultaneously change the pressure angles of the two grinding surfaces 101A and 101B. Thereby, when correcting the bias, the dressing of the grinding groove 101 can be efficiently performed.

[0085] (2) The dressing devices 5A and 5B according to the second aspect are the dressing devices 5A and 5B of (1), wherein when the spiral grinding groove 101 grinds one tooth 201 of the gear 200, it has a first portion 101s that contacts a first end 201a on one side of the tooth 201 in the tooth flank direction Ds of the tooth 201, and a second portion 101t that contacts a second end 201b on the other side of the tooth 201 in the tooth flank direction Ds. When performing dressing, the control unit 9 gradually rotates the dressing tools 51A and 51B as it approaches from the first portion 101s to the second portion 101t.

[0086] Thereby, the pressure angles of the two grinding surfaces 101A and 101B gradually change along the tooth flank direction Ds from the first portion 101s to the second portion 101t of the grinding groove 101. Therefore, when machining the gear 200 with the grinding groove 101, the pressure angle can be smoothly adjusted from the first portion 101s that contacts the first end 201a on one side of the tooth flank direction Ds of the tooth 201 to the second portion 101t that contacts the second end 201b of the tooth 201.

[0087] (3) The dressing devices 5A and 5B according to the third aspect are the dressing devices 5A and 5B of (2), and in the cross-section including the grinding wheel rotation axis O4, in the first part 101s, the control unit 9 positions the tips on the first side Dw1 of the groove width direction Dw with respect to the groove center axis Cm located in the middle of the grinding groove 101 in the groove width direction Dw so as to tilt the dressing tools 51A and 51B, and in the cross-section including the grinding wheel rotation axis O4, in the second part 101t, the dressing tools 51A and 51B are tilted so that the tips are located on the second side Dw2 of the groove width direction Dw with respect to the groove center axis Cm.

[0088] As a result, the pressure angles of the first part 101s and the second part 101t can be adjusted in a state where the change amount of the pressure angle between the first part 101s and the second part 101t is close to 0.

[0089] (4) The dressing devices 5A and 5B according to the fourth aspect are the dressing devices 5A of any one of (1) to (3), and the dressing tool 51A has one dressing part 510, and the pair of dressing surfaces 511 and 512 are formed on the side surface of the dressing part 510 facing opposite sides in the direction in which the tool rotation axis O5 extends.

[0090] As a result, when the dressing part 510 is inserted into the grinding groove 101 of the grinding wheel T, the pair of dressing surfaces 511 and 512 come into contact with two adjacent grinding surfaces 101A and 101B in the groove width direction Dw of the grinding groove 101. As a result, dressing can be simultaneously performed on both surfaces of the grinding groove 101 in the groove width direction Dw.

[0091] (5) The dressing devices 5A and 5B according to the fifth aspect are any one of the dressing devices 5A and 5B in (1) to (3). The dressing tool 51B has, at its tip, a first dressing portion 520 and a second dressing portion 530 arranged at an interval in the extending direction of the tool rotation axis O5 with respect to the first dressing portion 520. The dressing surface 521 formed on the first dressing portion 520 and the dressing surface 531 formed on the second dressing portion 530 face each other in the extending direction of the tool rotation axis O5.

[0092] (6) The dressing device 5B according to the sixth aspect is any one of the dressing devices 5B in (1) to (5). The spiral grinding groove 101 has a non-uniform lead dimension L which is the length in the extending direction of the grinding wheel rotation axis O4 when the grinding wheel T rotates a predetermined number of times. When performing dressing, the control unit 9 adjusts the turning amount of the dressing tool 51B so as to correspond to the change amount of the lead dimension L.

[0093] Thereby, while turning the dressing tool 51A, by changing the lead dimension L, dressing can be performed so as to change the pressure angles of the two grinding surfaces 101A and 101B while finely adjusting them simultaneously. Thereby, when correcting the bias, dressing of the grinding groove 101 can be performed more efficiently.

[0094] (7) The gear grinding devices 1A and 1B according to the seventh aspect include a work table 3 that rotatably supports a work W to be a gear 200, a grinding wheel T that grinds the work W, a grinding wheel support portion 4 that rotationally drives the grinding wheel T around the grinding wheel rotation axis O4, and any one of the dressing devices 5A and 5B in (1) to (6).

[0095] Thereby, in the gear grinding devices 1A and 1B, dressing can be efficiently performed on the grinding wheel T used for grinding the gear 200.

[0096] (8) The dressing method S1 of the grinding wheel T according to the tenth aspect is the dressing method S1 of the grinding wheel T in any one of the dressing devices 5A and 5B from (1) to (6), and includes a step S3 of rotating the grinding wheel T around the grinding wheel rotation axis O4, and a step of dressing two adjacent grinding surfaces 101A and 101B in the groove width direction Dw with a pair of dressing surfaces 511 and 512, and changing the angle of the pair of dressing surfaces 511 and 512 with respect to the two grinding surfaces 101A and 101B by rotating the dressing tools 51A and 51B around the tool rotation axis O6 by the tool turning unit 53, namely step S5.

[0097] Thereby, dressing can be performed so as to simultaneously change the pressure angles of the two grinding surfaces 101A and 101B. Thereby, when correcting the bias, dressing of the grinding groove 101 can be efficiently performed.

Industrial Applicability

[0098] According to the above-described dressing device, gear grinding device, and grinding wheel dressing method, even a grinding wheel having a grinding surface with a complex shape can be efficiently dressed.

Explanation of Reference Numerals

[0099] 1A, 1B Gear grinding device 2 Bed 3 Worktable 4 Grinding wheel support part 5A, 5B Dressing device 6 Tailstock 7 Tailstock support part 8 Work turning and conveying part 9 Control part 41 Grinding wheel support part main body 42 Grinding wheel moving part 43 Grinding wheel driving part 50 Dressing mechanism 51A, 51B Dressing tool 52 Tool rotating part 53 Tool turning part 54 Rotating shaft 55 Dressing device moving part 65 Tailstock moving part 71 Support part body 75 First guide rail 76 Second guide rail 81 CPU 82 ROM 83 RAM 84 HDD 85 Signal transmission module 91 Grinding wheel control part 92 Tool rotation control part 93 Tool swiveling control part 94 Output part 100 Grinding teeth 101 Grinding groove 101A Grinding surface (first grinding surface) 101B Grinding surface (second grinding surface) 101C Grinding surface (first grinding surface) 101D Grinding surface (second grinding surface) 101b Groove bottom surface 101c Intermediate part 101d Tooth tip end surface 101s First part 101t Second part 200 Gear 201 Teeth 201a First end 201b Second end 500 Tool body part 510 Dressing part 511, 521 Dressing surface (first dressing surface) 512, 531 Dressing surface (second dressing surface) 520 First dressing part 522 Tip end surface 530 Second dressing part 532 Tip end surface 540 Base bottom surface Cm Groove center axis Ct Tool center axis D1 First direction D2 Second direction Da Rotation Axis Direction Da1 First Side Da2 Second Side Dg Tooth Profile Direction Dr Radial Direction Dri Inner Side Dro Outer Side Ds Tooth Rib Direction Dv Vertical Direction Dw Groove Width Direction Dw1 First Side Dw2 Second Side L Lead Dimension O3 Table Axis O4 Grinding Wheel Rotation Axis O5 Tool Rotation Axis O6 Tool Swivel Axis P1 Dressing Device Standby Position P2 Dressing Device Use Position S1 Dressing Method S2 Preparation Process S3 Process of Rotating the Grinding Wheel S4 Process of Rotationally Driving the Dressing Tool S5 Process of Performing Dressing T Grinding Wheel W Workpiece θ1, θ2 Inclination Angles

Claims

Claim 1 A dressing device for a grinding wheel having grinding grooves that are continuously spiral around a grinding wheel rotation axis, the dressing device being relatively movable in a first direction orthogonal to the grinding wheel rotation axis and being capable of dressing the grinding grooves, and a control unit that controls the operation of the dressing device, comprising: the dressing device includes: a disk-shaped dressing tool that is rotationally driven around a tool rotation axis extending along the grinding wheel rotation axis and has, at its tip, a pair of dressing surfaces capable of dressing two adjacent grinding surfaces in the groove width direction on the surface constituting the grinding groove; a tool turning unit that turns the dressing tool around a tool turning axis orthogonal to the tool rotation axis and the first direction; and the control unit rotates the grinding wheel around the grinding wheel rotation axis, rotates the dressing tool around the tool rotation axis, dresses two adjacent grinding surfaces in the groove width direction with the pair of dressing surfaces, and changes the angle of the pair of dressing surfaces with respect to the two grinding surfaces by turning the dressing tool around the tool turning axis by the tool turning unit; the spiral grinding groove has a first portion that contacts a first end on one side of the tooth in the tooth flanks direction and a second portion that contacts a second end on the other side of the tooth in the tooth flanks direction when grinding one tooth of a gear; the control unit in a cross section including the grinding wheel rotation axis, at the first portion, inclines the dressing tool so that the tip is located on a first side in the groove width direction with respect to a groove center axis located in the middle of the grinding groove in the groove width direction; in a cross section including the grinding wheel rotation axis, at the second portion, inclines the dressing tool so that the tip is located on a second side in the groove width direction with respect to the groove center axis. A dressing device Claim 2 The dressing device according to claim 1, wherein the control unit gradually turns the dressing tool as it approaches from the first portion to the second portion when dressing. Claim 3 The dressing tool has one dressing portion at its tip, and the pair of dressing surfaces are formed on the side surface of the dressing portion facing opposite sides in the direction in which the tool rotation axis extends. The dressing device according to claim 1 or 2. Claim 4 The dressing tool has, at the tip, a first dressing part and a second dressing part arranged at an interval in a direction in which the tool rotation axis extends with respect to the first dressing part. The dressing device according to claim 1 or 2, wherein the dressing surfaces formed on the first dressing part and the dressing surfaces formed on the second dressing part face each other in the direction in which the tool rotation axis extends.

5. The spiral grinding groove has a non-uniform lead dimension, which is the length in the direction in which the grinding wheel rotation axis extends when the grinding wheel rotates a predetermined number of times. The dressing device according to any one of claims 1 to 4, wherein the control unit adjusts the turning amount of the dressing tool so as to correspond to the change amount of the lead dimension when dressing.

6. A worktable that rotatably supports a work that becomes a gear. A grinding wheel for grinding the work. A grinding wheel support part that rotationally drives the grinding wheel around the grinding wheel rotation axis. A gear grinding device comprising the dressing device according to any one of claims 1 to 5.

7. A method for dressing a grinding wheel in the dressing device according to any one of claims 1 to 5, comprising: a step of rotating the grinding wheel around the grinding wheel rotation axis; a step of rotationally driving the dressing tool around the tool rotation axis; a step of dressing two adjacent grinding surfaces in the groove width direction with a pair of dressing surfaces, and changing the angle of the pair of dressing surfaces with respect to the two grinding surfaces by turning the dressing tool around the tool turning axis by the tool turning part.

Images