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EP-4737039-A1 - GEAR GRINDER AND GEAR GRINDING METHOD

EP4737039A1EP 4737039 A1EP4737039 A1EP 4737039A1EP-4737039-A1

Abstract

A gear grinder (1) includes a workpiece rotation mechanism (10), a grinding wheel rotation mechanism (30), and a first movement mechanism (41). The workpiece rotation mechanism (10) rotates a workpiece (9) having a plurality of teeth (91) on an outer peripheral surface about a workpiece axis (X1) which is a central axis thereof. The grinding wheel rotation mechanism (30) rotates a grinding wheel (20) having threads (21) on an outer peripheral surface about a grinding wheel axis which is a central axis thereof. The first movement mechanism (41) moves the grinding wheel (20) from one end to the other end of the workpiece (9) in the tooth width direction. The gear grinder (1) grinds the workpiece (9) by synchronously rotating the workpiece (9) and the grinding wheel (20) while the workpiece (9) and the grinding wheel (20) mesh with each other and moving the grinding wheel (20) by the first movement mechanism (41). The workpiece (9) includes a first region located at a center portion in the tooth width direction and a second region closer to an end portion in the tooth width direction than the first region. The movement speed (AF) of the grinding wheel (20) in the tooth width direction when grinding the first region is lower than the movement speed (AF) of the grinding wheel (20) in the tooth width direction when grinding the second region.

Inventors

  • YANASE, YOSHIKOTO

Assignees

  • Nidec Machine Tool Corporation

Dates

Publication Date
20260506
Application Date
20251029

Claims (14)

  1. A gear grinder (1) for grinding a workpiece (9) serving as a gear, the gear grinder (1) comprising: a workpiece rotation mechanism (10) that rotates a workpiece (9) having a plurality of teeth (91) on an outer peripheral surface about a workpiece axis (X1) that is a central axis of the workpiece (9); a grinding wheel rotation mechanism (30) that rotates a grinding wheel (20) having threads (21) on an outer peripheral surface about a grinding wheel axis which is a central axis of the grinding wheel (20); and a first movement mechanism (41) that moves the grinding wheel (20) from one end to an other end of the workpiece (9) in a tooth width direction parallel to the workpiece axis (X1), wherein the workpiece rotation mechanism (10) and the grinding wheel rotation mechanism (30) synchronously rotate the workpiece (9) and the grinding wheel (20) in a state where the workpiece (9) and the grinding wheel (20) mesh with each other, and the first movement mechanism (41) moves the grinding wheel (20) to grind the workpiece (9), the workpiece (9) includes: a first region (A1) located at a center portion in the tooth width direction; and a second region (A2) closer to an end portion in the tooth width direction than the first region (A1), and a movement speed (AF) of the grinding wheel (20) in the tooth width direction when grinding the first region (A1) is lower than a movement speed (AF) of the grinding wheel (20) in the tooth width direction when grinding the second region (A2).
  2. The gear grinder (1) according to claim 1, wherein the first movement mechanism (41) gradually changes a movement speed (AF) of the grinding wheel (20) in the tooth width direction between the first region (A1) and the second region (A2).
  3. The gear grinder (1) according to claim 2, wherein the first movement mechanism (41) changes a movement speed (AF) of the grinding wheel (20) in the tooth width direction in a sinusoidal shape.
  4. The gear grinder (1) according to any one of claims 1 to 3, wherein a maximum value of a movement speed (AF) of the grinding wheel (20) in the tooth width direction is more than 1 time and 20 times or less a minimum value of a movement speed (AF) of the grinding wheel (20) in the tooth width direction.
  5. The gear grinder (1) according to claim 4, wherein the movement speed (AF) of the grinding wheel (20) in the tooth width direction becomes the minimum value only once while the first movement mechanism (41) moves the grinding wheel (20) once from one end to an other end of the workpiece (9) in the tooth width direction.
  6. The gear grinder (1) according to any one of claims 1 to 5, further comprising a control unit that calculates a movement speed (AF) of the grinding wheel (20) in the tooth width direction based on a change rate of a movement speed (AF) of the grinding wheel (20) in the tooth width direction and a movement time of the grinding wheel (20) in the tooth width direction.
  7. The gear grinder (1) according to any one of claims 1 to 6, further comprising a second movement mechanism that moves the grinding wheel (20) with respect to the workpiece (9) in a shift direction parallel to the grinding wheel axis, wherein the grinding wheel (20) is moved at a constant speed in the shift direction by the second movement mechanism while moving the grinding wheel (20) in the tooth width direction by the first movement mechanism.
  8. A gear grinding method for grinding a workpiece (9) serving as a gear, the gear grinding method comprising: a step of grinding a workpiece (9) by rotating a workpiece (9) having a plurality of teeth (91) on an outer peripheral surface thereof about a workpiece axis (X1) that is a central axis thereof, meshing a grinding wheel (20) having threads (21) on an outer peripheral surface thereof with the workpiece (9) while rotating the grinding wheel (20) about a grinding wheel axis which is a central axis thereof, and moving the grinding wheel (20) from one end to an other end of the workpiece (9) in a tooth width direction parallel to the workpiece axis (X1), wherein the workpiece (9) includes: a first region (A1) located at a center portion in the tooth width direction; and a second region (A2) closer to an end portion in the tooth width direction than the first region (A1), and a movement speed (AF) of the grinding wheel (20) in the tooth width direction when grinding the first region (A1) is lower than a movement speed (AF) of the grinding wheel (20) in the tooth width direction when grinding the second region (A2).
  9. The gear grinding method according to claim 8, wherein a movement speed (AF) of the grinding wheel (20) in the tooth width direction is gradually changed between the first region (A1) and the second region (A2).
  10. The gear grinding method according to claim 9, wherein a movement speed (AF) of the grinding wheel (20) in the tooth width direction is changed in a sinusoidal shape.
  11. The gear grinding method according to any one of claims 8 to 10, wherein a maximum value of a movement speed (AF) of the grinding wheel (20) in the tooth width direction is more than 1 time and 20 times or less a minimum value of a movement speed (AF) of the grinding wheel (20) in the tooth width direction.
  12. The gear grinding method according to claim 11, wherein a movement speed (AF) of the grinding wheel (20) in the tooth width direction becomes the minimum value only once while the grinding wheel (20) moves once from one end to an other end of the workpiece (9) in the tooth width direction.
  13. The gear grinding method according to any one of claims 8 to 12, wherein a movement speed (AF) of the grinding wheel (20) in the tooth width direction is calculated based on a change rate of a movement speed (AF) of the grinding wheel (20) in the tooth width direction and a movement time of the grinding wheel (20) in the tooth width direction.
  14. The gear grinding method according to any one of claims 8 to 13, wherein, in the step, the grinding wheel (20) is moved at a constant speed in a shift direction parallel to the grinding wheel axis while the grinding wheel (20) is moved in the tooth width direction.

Description

Technical Field The present invention relates to a gear grinder and a gear grinding method. Background Art Conventionally, a gear grinder that grinds a workpiece serving as a gear is known. A gear grinder synchronously rotates a workpiece having teeth and a grinding wheel having threads, and brings the workpiece and the grinding wheel into contact with each other such that the groove of the grinding wheel meshes with the teeth of the workpiece. Then, by moving the contact point between the workpiece and the grinding wheel in the tooth width direction, the tooth of the workpiece is ground from one end to the other end in the tooth width direction. A conventional gear grinder is described, for example, in Patent Literature 1. Patent Literature 1: JP 2016-083748 A Summary of Invention Technical Problem Feed marks (tool marks) are generated on the surface of the tooth ground by the gear grinder. The feed mark is minute undulations formed on the surface of the tooth by the grinding wheel. The feed mark is periodically formed at a pitch corresponding to the movement speed of the grinding wheel. When the gears are meshed, noise may occur due to the feed mark. Specifically, in addition to noise having a frequency corresponding to the number of teeth of the gear, noise having a frequency corresponding to the pitch of the feed marks may occur. Therefore, an object of the present invention is to provide a gear grinder and a gear grinding method capable of reducing noise caused by feed marks. Solution to Problem A first invention provides a gear grinder for grinding a workpiece serving as a gear, the gear grinder including: a workpiece rotation mechanism that rotates a workpiece having a plurality of teeth on an outer peripheral surface about a workpiece axis that is a central axis of the workpiece; a grinding wheel rotation mechanism that rotates a grinding wheel having threads on an outer peripheral surface about a grinding wheel axis which is a central axis of the grinding wheel; and a first movement mechanism that moves the grinding wheel from one end to the other end of the workpiece in a tooth width direction parallel to the workpiece axis, in which the workpiece rotation mechanism and the grinding wheel rotation mechanism synchronously rotate the workpiece and the grinding wheel in a state where the workpiece and the grinding wheel mesh with each other, and the first movement mechanism moves the grinding wheel to grind the workpiece, the workpiece includes: a first region located at a center portion in the tooth width direction; and a second region closer to an end portion in the tooth width direction than the first region, and a movement speed of the grinding wheel in the tooth width direction when grinding the first region is lower than a movement speed of the grinding wheel in the tooth width direction when grinding the second region. A second invention provides a gear grinding method for grinding a workpiece serving as a gear, the gear grinding method including: a step of grinding a workpiece by rotating a workpiece having a plurality of teeth on an outer peripheral surface thereof about a workpiece axis that is a central axis thereof, meshing a grinding wheel having threads on an outer peripheral surface thereof with the workpiece while rotating the grinding wheel about a grinding wheel axis which is a central axis thereof, and moving the grinding wheel from one end to an other end of the workpiece in a tooth width direction parallel to the workpiece axis, in which the workpiece includes: a first region located at a center portion in the tooth width direction; and a second region closer to an end portion in the tooth width direction than the first region, and a movement speed of the grinding wheel in the tooth width direction when grinding the first region is lower than a movement speed of the grinding wheel in the tooth width direction when grinding the second region. Advantageous Effects of Invention According to the first invention and the second invention, the pitch of the feed mark formed on the surface of the tooth by the grinding wheel can be made different between the first region and the second region. Accordingly, it is possible to reduce noise caused by the feed mark at the time of meshing the gear. In addition, noise perceived by a person can be reduced by increasing the frequency of noise generated from the first region that meshes relatively strongly. Brief Description of Drawings Fig. 1 is a diagram illustrating a configuration of a gear grinder.Fig. 2 is a flowchart illustrating a flow of an operation of the gear grinder.Fig. 3 is a diagram illustrating a state of a workpiece and a grinding wheel in step S5.Fig. 4 is a diagram illustrating a state of a workpiece and a grinding wheel in step S5.Fig. 5 is a diagram illustrating a state of the workpiece and the grinding wheel in step S5.Fig. 6 is a graph illustrating a change in a movement speed of a grinding wheel.Fig. 7 is a graph illustratin