Gear cutting device

Abstract

To provide a CNC vertical hobbing machine which can manufacture several kinds of gears.SOLUTION: A CNC vertical hobbing machine 60 has: a collet spindle 22 configured to support a workpiece; and an arbor 42 configured to support a cutter 14 for cutting the workpiece. The CNC vertical hobbing machine includes: a support plate 24 which supports the collet spindle 22 in such a manner that the collet spindle can operate around a virtual line F2 and stops the collet spindle at a predetermined position in a circumferential direction centered on the virtual line F2; a support table 44 which supports the cutter 14 in such a manner that the cutter can operate around a virtual line G1 intersecting with a virtual line C1; and a lift platform 45 which operates the arbor 42 in a vertical direction. The virtual line F2 and the virtual line G1 are horizontally arranged. The virtual line C1 and the virtual line F2 are arranged parallel to each other in a plane formed when the lift platform 45 is viewed from directly above in the vertical direction. The virtual line G1 is disposed on an extension line of the virtual line F1; the virtual line F1 and the virtual line F2 intersect at 90 degrees; and the virtual line C1 and the virtual line G1 intersect at 90 degrees.SELECTED DRAWING: Figure 4C

Description

[Technical field]

[0001] The present disclosure relates to a gear cutting device that cuts a workpiece to manufacture a gear. [Background technology]

[0002] An example of a gear cutting machine that manufactures gears by cutting a workpiece is described in Patent Document 1. The CNC processing device described in Patent Document 1 is a CNC processing device for spiral bevel gears or hypoid gears, and has a work gear spindle that rotatably supports the work gear, a tool spindle that rotatably supports a tool that processes the work gear, and a moving means that moves the work gear spindle and the tool spindle relatively in a maximum of three different directions.

[0003] In addition, the CNC machining device described in Patent Document 1 has a work gear spindle or a tool spindle that is inclined at a fixed, non-adjustable inclination angle with respect to a reference axis for all bevel gears to be machined, and is adapted to be continuously swiveled around the reference axis by a swiveling means. Furthermore, in the CNC machining device described in Patent Document 1, the other spindle defines a reference plane with its axis and the reference axis, and the angular position is adjustable around a rotation axis perpendicular to the reference plane for each bevel gear to be machined, and the angular position is not changed during machining. Furthermore, in the CNC machining device described in Patent Document 1, the inclination angle and the angular position are set so that a predetermined rolling motion is realized between the work gear and the tool, and the inclination angle is set to be the same angle as ΔΓmax, which is the maximum value of the rotation range of the machine root angle when machining a bevel gear with a six-axis device. An example of a gear cutting machining device that cuts a workpiece to manufacture gears is also described in Patent Document 2. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4381780 [Patent Document 2] Patent No. 5040208 Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors of the present application have found that the processing devices described in Patent Documents 1 and 2 do not describe the manufacturing of multiple types of gears, such as straight bevel gears, spiral bevel gears, spur gears, helical gears, worm wheels, and worms, and that there is room for improvement in this regard.

[0006] An object of the present disclosure is to provide a gear cutting device capable of manufacturing multiple types of gears, such as straight bevel gears, spiral bevel gears, spur gears, helical gears, worm wheels, and worms. [Means for solving the problem]

[0007] The present disclosure relates to a gear cutting device having a workpiece support section that supports a workpiece rotatably about a first virtual line, and a cutting tool support section that supports a cutting tool for cutting the workpiece rotatably about a second virtual line, the device including a first movable section that supports the workpiece support section operatively in a circumferential direction about a third virtual line and stops the workpiece support section at a predetermined position in the circumferential direction about the third virtual line, and a second movable section that supports the cutting tool support section operatively and stopably about a fourth virtual line that intersects with the second virtual line. The gear cutting device has a movable part and an operating mechanism which operates the cutting tool support part in a vertical direction, wherein the third virtual line and the fourth virtual line are arranged horizontally, within a plane in which the operating mechanism is viewed from directly above in the vertical direction, the second virtual line and the third virtual line are arranged parallel to each other, the fourth virtual line is arranged on an extension of the first virtual line, the first virtual line and the third virtual line intersect at an angle of 90 degrees, and the second virtual line and the fourth virtual line intersect at an angle of 90 degrees. Effect of the Invention

[0008] The gear cutting apparatus of the present disclosure can manufacture multiple types of gears, such as straight bevel gears, spiral bevel gears, spur gears, helical gears, worm wheels, and worms. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a spiral bevel gear that can be manufactured by a CNC vertical hobbing machine, which is an example of a gear cutting device. [Diagram 2] FIG. 2 is a partial side view of a cutter, which is an example of a cutting tool for cutting a workpiece with a CNC vertical hobbing machine. [Figure 3A] FIG. 3 is a front view of the cutter shown in FIG. 2. [Figure 3B] FIG. 2 is a front view of a hob, which is another example of a cutting tool for cutting a workpiece. [Figure 3C] FIG. 3C is a side view of the hob shown in FIG. 3B. [Figure 4A] FIG. 1 is a schematic front view showing an overall configuration of a CNC vertical hobbing machine. [Figure 4B] FIG. 1 is a schematic front view showing an overall configuration of a CNC vertical hobbing machine. [Figure 4C] FIG. 1 is a schematic plan view showing an overall configuration of a CNC vertical hobbing machine. [Figure 4D] FIG. 2 is a block diagram showing the control system of a CNC vertical hobbing machine. [Diagram 5] FIG. 1 is a conceptual diagram showing a machining example 1 using a CNC vertical hobbing machine. [Figure 6] FIG. 1 is a conceptual diagram showing a second example of machining using a CNC vertical hobbing machine. [Figure 7] FIG. 13 is a conceptual diagram showing a third example of machining using a CNC vertical hobbing machine. [Figure 8] FIG. 13 is a conceptual diagram showing machining example 4 using a CNC vertical hobbing machine. [Figure 9] FIG. 5 is a conceptual diagram showing machining example 5 using a CNC vertical hobbing machine. [Figure 10] FIG. 13 is a conceptual diagram showing a sixth example of machining using a CNC vertical hobbing machine. [Figure 11] FIG. 7 is a conceptual diagram showing machining example 7 using a CNC vertical hobbing machine. [Figure 12] FIG. 13 is a conceptual diagram showing machining example 8 using a CNC vertical hobbing machine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] An embodiment of a gear cutting device will be described with reference to the drawings. A CNC vertical hobbing machine, which is an example of a gear cutting device, is a device that can manufacture a plurality of types of gears, such as straight bevel gears, spiral bevel gears, spur gears, helical gears, worm wheels, and worms, by cutting a workpiece with a rotating cutting tool. The rotating cutting tool is moved along the vertical direction, that is, the longitudinal direction, relative to the workpiece. In the drawings for explaining the embodiment of the CNC vertical hobbing machine, the same parts are generally designated by the same reference numerals, and repeated explanations thereof will be omitted.

[0011] (An example of a gear manufactured using a CNC vertical hobbing machine) FIG. 1 shows a spiral bevel gear 10, which is an example of a number of types of gears that can be manufactured by a CNC (Computerized Numerical Control) vertical hobbing machine. The spiral bevel gear 10 is made of a metal material. The metal material includes alloy steels for mechanical construction, such as chrome steel (SCr), chrome molybdenum steel (SCM), nickel chrome steel (SNC), and the like. The spiral bevel gear 10 in a manufactured state is used, for example, as a component of a power transmission device of a vehicle, and is rotated around a virtual line A1. The spiral bevel gear 10 has a number of teeth arranged along the rotation direction. A tooth trace 11 of each tooth of the spiral bevel gear 10 is a curve on a pitch cone, and the tooth trace 11 has a helix angle β1.

[0012] For convenience, FIG. 1 shows a right-handed spiral bevel gear 10. The pitch circle of the spiral bevel gear 10, which is an example of a manufacturing target, relatively increases from the upper end surface 12 to the lower end surface 13. The pitch cone angle δ1 is the acute angle between the imaginary line A1 and the imaginary line B1 that indicates the pitch cone of the spiral bevel gear 10. The helix angle β1 is the acute angle between the imaginary line A1 and the imaginary line B2. The imaginary line B2 is a tangent to the curve that indicates the tooth trace 11, and is a straight line that passes through point Q1. The imaginary lines A1 and B1 intersect at point Q1.

[0013] (Cutting tool explanation) 2 and 3A show an example of a cutter 14 as a cutting tool. The cutter 14 is a special cutter for cutting a workpiece to obtain a gear as a product, for example, a spiral bevel gear 10. The cutter 14 has a cylindrical boss portion 15 and a cutting blade 16 provided on the outer peripheral surface of the boss portion 15. The cutting blades 16 protrude from the outer peripheral surface of the boss portion 15 and are provided at predetermined intervals in the circumferential direction of the boss portion 15. The rotation center of the cutter 14 is shown by a virtual line C1, and a virtual line E1 perpendicular to the virtual line C1 is shown. In the case of the cutter 14 for manufacturing the spiral bevel gear 10, the cutting blade 16 is provided within a range of a predetermined angle θ3 or less in the rotation direction around the virtual line C1. The predetermined angle θ3 is, for example, 180 degrees. The tooth ridge of the cutter 14 is twisted with respect to the virtual line E1, and a virtual line D1 along the tooth ridge of the cutter 14 is shown. The direction in which the tooth trace of the cutter 14 twists with respect to the imaginary line E1 can be right-handed or left-handed. The cutter 14 has a lead angle (twist angle) γ1 between the imaginary lines E1 and D1. The lead angle γ1 is the acute angle formed between the imaginary lines E1 and D1.

[0014] (Description of hobbing machine) 4A, 4B, and 4C show an example of a CNC vertical hobbing machine 60. The CNC vertical hobbing machine 60 has a work support mechanism 20, a work drive mechanism 21, a cutting tool support mechanism 40, and a cutting tool drive mechanism 41. The work support mechanism 20 is a mechanism that supports a workpiece W1. The work support mechanism 20 has a collet spindle 22, a gear case 23, a support plate 24, a swivel base 25, and a table 26. The collet spindle 22 is supported by the gear case 23 so as to be rotatable about a virtual line F2. The gear case 23 is fixed to the support plate 24.

[0015] The support plate 24 can move in a circumferential direction around the imaginary line F2 relative to the swivel base 25, and can be stopped and fixed at a predetermined position in the circumferential direction. An operator can move the support plate 24 within a predetermined angle range around the imaginary line F2 relative to the swivel base 25, and fix the support plate 24 at a predetermined position relative to the swivel base 25. The operation of fixing the support plate 24 at a predetermined position relative to the swivel base 25 is performed, for example, by tightening a bolt or a nut. When the support plate 24 moves around the imaginary line F2 relative to the swivel base 25, the collet spindle 22 revolves around the imaginary line F2. The position at which the support plate 24 is fixed to the swivel base 25 is determined according to the pitch cone angle δ1 of the spiral bevel gear 10 to be manufactured. The imaginary line F2 is arranged along the horizontal direction. Furthermore, as shown in FIG. 2, regardless of the stop position of the support plate 24 relative to the swivel base 25, the imaginary lines F1 and F2 do not intersect within a plane perpendicular to the imaginary line F2.

[0016] The swivel base 25 is attached to a table 26, which is configured to be operable in a horizontal direction, and in the left and right directions in Fig. 4C. As shown in Fig. 4D, a table drive mechanism 70 is provided for operating and stopping the table 26. The table drive mechanism 70 has an electric servo motor 71, a ball screw mechanism, etc., and the table drive mechanism 70 operates the table 26 in the horizontal direction and stops it at a predetermined position.

[0017] The workpiece drive mechanism 21 is a mechanism for rotating and stopping the workpiece W1. As shown in FIG. 4A, the workpiece drive mechanism 21 has a first gear 27, a second gear 28 fixed to a rotating shaft 91, a male-connected first bevel gear (not shown) fixed to the rotating shaft 91, a second bevel gear (not shown) fixed to the rotating shaft 31 and meshing with the first bevel gear, a third gear 29 fixed to the rotating shaft 31, a fourth gear 30, and an electric servo motor 32. The rotating shaft 91 rotates around a virtual line F2. The first gear 27 is fixed to the collet spindle 22. The second gear 28 is meshed with the first gear 27. The second gear 28 is connected to the rotating shaft 31, and the third gear 29 is attached to the rotating shaft 31. The third gear 29 is meshed with the fourth gear 30. The fourth gear 30 is rotated and stopped by an electric servo motor 32. The collet spindle 22 is an attachment to which the workpiece W1 is attached and detached.

[0018] When the rotational force of the electric servo motor 32 is transmitted to the collet spindle 22 via the fourth gear 30, the rotating shaft 31, the rotating shaft 28, the third gear 29, and the second gear 28, the collet spindle 22 is rotated about the imaginary line F1. The work drive mechanism 21 switches the rotation direction of the work W1 and controls the rotation speed of the work W1.

[0019] (Cutting tool support mechanism and cutting tool drive mechanism) 4C shows a cutting tool support mechanism 40 and a cutting tool drive mechanism 41. The cutting tool support mechanism 40 is a mechanism that supports a cutting tool. The cutting tool support mechanism 40 has an arbor 42, a holder 46, an arbor support part 43, a support table 44, and a lifting platform 45. The arbor 42 is a rotating shaft, and an operator can attach and detach the cutter 14 to and from the arbor 42. The holder 46 and the arbor support part 43 are attached to the support table 44, and the holder 46 and the arbor support part 43 support the arbor 42 rotatably about the imaginary line C1.

[0020] The support table 44 is attached to a lifting platform 45, and the lifting platform 45 is attached to a guide rail 47. The support table 44 is configured to be able to operate and stop around an imaginary line G1 by the lifting platform 45, and to be able to be fixed at a stop position. The imaginary line G1 is disposed, for example, along the horizontal direction.

[0021] Before the cutter 14 cuts the workpiece W1, the worker manually moves the support table 44 around the virtual line G1, stops the support table 44 at a predetermined position, and then fixes the support table 44. The work of fixing the support table 44 is, for example, tightening bolts and nuts. The stop position of the support table 44 is determined based on the helix angle β1 of the spiral bevel gear 10 to be manufactured and the lead angle γ1 of the cutter 14. Furthermore, the lifting platform 45 is supported by the guide rail 47 so that it can move vertically, that is, rise and fall. Furthermore, a table lifting mechanism 72 is provided to lift, lower, and stop the lifting platform 45. The table lifting mechanism 72 has, for example, an electric servo motor 73 and a ball screw mechanism.

[0022] The cutting tool drive mechanism 41 is a mechanism for driving the cutting tool. The cutting tool drive mechanism 41 has an arbor 42, a gear transmission, and an electric spindle motor 48 shown in FIG. 4D. The electric spindle motor 48 is supported by the support table 44. The electric spindle motor 48 can switch the rotation direction. When the rotation force of the electric spindle motor 48 is transmitted to the arbor 42 via the gear transmission, the arbor 42 and the cutter 14 are rotated forward or backward. The cutting tool drive mechanism 41 switches the rotation direction of the cutter 14 and controls the rotation speed of the cutter 14. When the support table 44 is rotated and stopped around the virtual line G1, the arbor 42 and the arbor support part 43 are rotated and stopped around the virtual line G1 in a plane perpendicular to the virtual line G1. In this way, the CNC vertical hobbing machine 60 can raise and lower the cutter 14 in the vertical direction. The CNC vertical hobbing machine 60 is an NC hobbing machine in which a control unit numerically controls the rotation speed of the cutter 14, the ascent and descent speed of the cutter 14, the rotation speed of the workpiece W1, and the like.

[0023] Further, a control panel 74 shown in FIG. 4D is provided. The control panel 74 is for controlling the CNC vertical hobbing machine 60. The control panel 74 has an operation unit 75, a control circuit 76, and a memory circuit 77. The operation unit 75 is operated by an operator. The operation unit 75 has a touch panel, a switch, a monitor, etc., and the operator can set the specifications of the spiral bevel gear 10 to be manufactured, the rotation speed of the electric servo motor 32, the rotation speed of the electric spindle motor 48, etc. by operating the operation unit 75. The specifications of the spiral bevel gear 10 include, for example, the number of teeth, the diameter of the tooth root circle, the total tooth depth, the tooth width, the pitch circle diameter, the pitch cone angle δ1, the helix angle β1, etc.

[0024] The control circuit 76 can automate, by numerical control, the rotation direction, rotation speed, rotation and stop of the electric servo motors 32, 71, 73 and the rotation direction, rotation speed, rotation and stop of the electric spindle motor 48, based on signals input from the operation unit 75 and data, programs, etc. stored in the memory circuit 77. The memory circuit 77 stores data, programs, etc. used for the control executed by the control circuit 76.

[0025] The layout of the CNC vertical hobbing machine 60 will be described. The virtual lines F2 and G1 are arranged horizontally. As shown in FIG. 4C, in a plane viewed from directly above the CNC vertical hobbing machine 60 in the vertical direction, the virtual lines C1 and F2 are arranged in parallel, and the virtual line G1 is arranged on an extension of the virtual line F1, and the virtual lines F1 and F2 are arranged to intersect at an angle of 90 degrees, and the virtual lines C1 and G1 are arranged to intersect at an angle of 90 degrees. As shown in FIG. 4A, when the CNC vertical hobbing machine 60 is viewed from the front, the virtual lines F1 and G1 are located on the same plane.

[0026] (Example of manufacturing a spiral bevel gear) A manufacturing example of the spiral bevel gear 10, that is, a processing example, is as follows. As shown in FIG. 4A, the collet spindle 22 to which the workpiece W1 is attached is rotated, and the cutter 14 is also rotated. Then, the cutter 14 is raised or lowered to cut the workpiece W1 and produce the spiral bevel gear 10. A method in which the cutter 14 rises to cut the workpiece W1 is called climb. A method in which the cutter 14 descends to cut the workpiece W1 is called conventional. In either method of cutting the workpiece W1, the cutter 14 is rotated clockwise in FIG. 4A, and chips generated by cutting the workpiece W1 fall downward.

[0027] When the spiral bevel gear 10 is manufactured by the CNC vertical hobbing machine 60 of the present disclosure, as shown in Figs. 4A and 4B, in a plane perpendicular to the imaginary line F2, the imaginary line B1 corresponding to the pitch cone of the spiral bevel gear 10 and the imaginary line H1 indicating the movement path (operation path) of the cutter 14 are parallel to each other, and the support plate 24 is fixed to the swivel table 25. That is, the cutter 14 cuts the workpiece W1 in a state in which the imaginary line F1 is inclined with respect to the imaginary line H1. The movement path of the cutter 14 means, for example, the movement path of the imaginary line C1 when the cutter 14 rises or falls.

[0028] Then, when the process of cutting the workpiece W with the cutter 14 is started by rotating the cutter 14 and rotating the workpiece W1, each time the cutter 14 rotates once, a tooth of a predetermined length is formed at intervals in the rotation direction of the workpiece W1. Furthermore, each time one rotation of the workpiece W1 is completed, the cutter 14 is controlled to move a predetermined amount in the direction along the imaginary line H1.

[0029] Here, the rotation speed of the cutter 14 and the rotation speed of the workpiece W1 are numerically controlled by the control panel 74 so that the workpiece W1 rotates by "1 / tooth number" while the cutter 14 rotates once, and a correction rotation amount corresponding to the helix angle β1 is given to the rotation amount of the workpiece W1. Therefore, depending on the helix direction of the tooth trace 11 of the workpiece W1, there are cases where the workpiece W1 rotates more than "1 / tooth number" rotation while the cutter 14 rotates once, and cases where the workpiece W1 rotates less than "1 / tooth number" rotation while the cutter 14 rotates once. During the machining of the spiral bevel gear 10, the table 26 is stopped. After the machining of the spiral bevel gear 10 is completed, the table 26 is operated in the horizontal direction, for example, to the right in FIG. 4A. Note that the acute angle formed between the virtual line F1 and the virtual line H1 is different between FIG. 4A and FIG. 4B.

[0030] [Processing example 1] FIG. 5 is a conceptual diagram showing an example of manufacturing a right-handed spiral bevel gear 10 by cutting a workpiece W1 with a right-handed cutter 14. Note that FIG. 5 assumes a plane perpendicular to a virtual line G1, and the virtual line G1 is a horizontal straight line. In FIG. 5, the intersection point J1 of the virtual line C1, the virtual line G1, the virtual line F1, and the virtual line H1 shown in FIG. 4A is shown. The intersection point J1 is located at the center of the cutter 14 in the direction of the virtual line C1. The inclination angle θ1 is an acute angle formed between the virtual line C1 and the virtual line H2. The virtual line H2 is a straight line along the horizontal direction. The cutter 14 is rotated in a first direction R1 around the virtual line C1. Also, the workpiece W1 is rotated in a second direction U2 around the virtual line F1. Here, the inclination angle θ1 is θ1=β1-γ1 is set to.

[0031] Here, a state is assumed as a first reference position in which the cutter 14 and the workpiece W are stopped, the imaginary line C1 is horizontal, and the holder 46 is located to the right of the intersection J1, before starting cutting of the workpiece W1. The worker moves the support table 44 from the first reference position counterclockwise around the imaginary line G1 by a tilt angle θ1, stops the support table 44, and then fixes the support table 44.

[0032] [Processing example 2] FIG. 6 is a conceptual diagram showing an example of manufacturing a right-handed spiral bevel gear 10 using a left-handed cutter 14. The cutter 14 is rotated in a first direction R1 around a virtual line C1. The workpiece W1 is rotated in a first direction U1 around a virtual line F1. Here, the inclination angle θ1 is θ1=β1+γ1 is set to.

[0033] Before starting cutting processing of the workpiece W1, the worker moves the support table 44 counterclockwise from the first reference position by a tilt angle θ1 around the imaginary line G1 while the cutter 14 and the workpiece W are stopped, and then fixes the support table 44.

[0034] [Processing example 3] FIG. 7 is a conceptual diagram showing an example of manufacturing a left-handed spiral bevel gear 10 using a left-handed cutter 14. The cutter 14 is rotated in a first direction R1 around a virtual line C1. The workpiece W1 is rotated in a first direction U1 around a virtual line F1. Here, the inclination angle θ1 is θ1=β1-γ1 Before starting cutting of the workpiece W1, while the cutter 14 and the workpiece W are stopped, the operator moves the support table 44 from the first reference position clockwise around the virtual line G1 by an inclination angle θ1, stops the table, and then fixes the support table 44.

[0035] [Processing example 4] FIG. 8 is a conceptual diagram showing an example of manufacturing a left-handed spiral bevel gear 10 using a left-handed cutter 14. The cutter 14 is rotated in a second direction R2 around a virtual line C1. The workpiece W1 is rotated in a first direction U1 around a virtual line F1. Here, the inclination angle θ1 is θ1=β1-γ1 is set to.

[0036] Before starting cutting of the workpiece W1, the operator assumes that the cutter 14 and the workpiece W are stopped, the imaginary line C1 is horizontal, and the holder 46 is located to the left of the intersection J1, as the second reference position. The operator moves the support table 44 from the second reference position clockwise around the imaginary line G1 by an inclination angle θ1, stops the support table 44, and then fixes the support table 44.

[0037] [Processing example 5] FIG. 9 is a conceptual diagram showing an example of manufacturing a left-handed spiral bevel gear 10 using a right-handed cutter 14. The cutter 14 is rotated in a first direction R1 around a virtual line C1. The workpiece W1 is rotated in a second direction U2 around a virtual line F1. Here, the inclination angle θ1 is θ1=β1+γ1 is set to.

[0038] Before starting cutting processing of the workpiece W1, while the cutter 14 and the workpiece W are stopped, the operator moves the support table 44 from the first reference position clockwise around the virtual line G1 by a tilt angle θ1, stops the table, and then fixes the support table 44.

[0039] [Processing example 6] FIG. 10 is a conceptual diagram showing an example of manufacturing a left-handed spiral bevel gear 10 using a right-handed cutter 14. The cutter 14 is rotated in a second direction R2 around a virtual line C1. The workpiece W1 is rotated in a second direction U2 around a virtual line F1. Here, the inclination angle θ1 is θ1=β1+γ1 is set to.

[0040] Before starting cutting processing of the workpiece W1, while the cutter 14 and the workpiece W are stopped, the operator moves the support table 44 from the second reference position clockwise around the virtual line G1 by a tilt angle θ1, stops the table, and then fixes the support table 44.

[0041] (Other gear manufacturing examples)

[0042] [Processing example 7] FIG. 11 is a conceptual diagram showing an example of manufacturing a spur gear 61 using a right-handed hob 14A. The tooth trace of the spur gear 61 is parallel to a virtual line C1. The hob 14A is rotated in a first direction R1 about the virtual line C1. The workpiece W2 is rotated in a second direction U2 about the virtual line F1. The workpiece W2 is cut by the hob 14A to manufacture the spur gear 61. When cutting the workpiece W2, the support plate 24 shown in FIG. 4A is positioned and fixed in a state in which the virtual line F1 shown in FIG. 11 is aligned along the vertical direction. That is, the virtual line F1 and the virtual line H1 are arranged parallel to each other in a plane perpendicular to the virtual line C1.

[0043] In addition, the inclination angle θ1 is θ1=-γ1 Before starting machining of the workpiece W2, while the hob 14A and the workpiece W2 are stopped, the operator moves the support table 44 from the first reference position clockwise around the virtual line G1 by an inclination angle θ1, stops the support table 44, and then fixes the support table 44.

[0044] [Processing example 8] FIG. 12 is a conceptual diagram showing an example of manufacturing a spur gear 61 using a left-handed cutter 14. The hob 14A is rotated in a first direction R1 around a virtual line C1. Also, the workpiece W2 is rotated in a first direction U1 around a virtual line F1. The workpiece W2 is cut by the hob 14A to manufacture the spur gear 61. Here, the inclination angle θ1 is θ1=γ1 is set to.

[0045] Before starting machining of the workpiece W2, while the hob 14A and the workpiece W2 are stopped, the operator moves the support table 44 from the first reference position counterclockwise around the virtual line G1 by a tilt angle θ1, stops the table, and then fixes the support table 44.

[0046] In addition, in Processing Example 7 and Processing Example 8, a straight bevel gear can be manufactured instead of the spur gear 61. Also, the shape and structure of the cutting tool, for example, the range of a predetermined angle in which the cutting blades are provided around the imaginary line, and the number of rows in which the cutting blades are provided in a direction along the imaginary line that is the center of the arbor, differ depending on the type of gear to be manufactured. For this reason, even if the lead angle γ1 of the cutting tool is "0 degrees" or more in Processing Example 7 and Processing Example 8, it may not be taken into consideration when setting the inclination angle θ1.

[0047] (Effects of the present disclosure) When cutting the workpiece W1 using a CNC vertical hobbing machine 60 to manufacture the spiral bevel gear 10, the workpiece W1 is cut by the cutter 14 in a state in which a virtual line B1 corresponding to the pitch cone of the spiral bevel gear 10 and a virtual line H1 of the cutter 14 are parallel to each other in a plane perpendicular to a virtual line C1 indicating the center of rotation of the cutter 14.

[0048] Moreover, by an operator operating the support table 44 about the imaginary line G1 and stopping and fixing it at any position, right-handed and left-handed spiral bevel gears 10 can be manufactured, and spiral bevel gears 10 having any desired helix angle β1 can be manufactured. Therefore, the helix angle β1 of the spiral bevel gear 10 to be manufactured can be set to any value equal to or greater than 20 degrees or less than 20 degrees. Furthermore, by an operator operating the support plate 24 about the imaginary line F2 and stopping and fixing it at any position, spiral bevel gears 10 having any desired pitch cone angle δ1 can be manufactured.

[0049] Furthermore, by operating the support plate 24 around the imaginary line F2 and stopping and fixing it at any position, the operator can satisfy both of the following: positioning the imaginary line F1 and the imaginary line H1 parallel to each other, and inclining the imaginary line F1 with respect to the imaginary line H1. Therefore, the CNC vertical hobbing machine 60 can manufacture both the spiral bevel gear 10 and the spur gear 61 whose tooth trajectory is parallel to the imaginary line C1. In addition, by stopping the imaginary line C1 at the first reference position or the second reference position and cutting the workpiece W1 with the cutter 14, it is also possible to manufacture a straight bevel gear or a worm whose tooth trajectory is straight.

[0050] In addition, in the CNC vertical hobbing machine 60 shown in each of FIG. 4A and FIG. 4B, by adjusting the position where the support plate 24 is fixed to the swivel 25, positioning the virtual line H1 and the virtual line F1 parallel to each other, and using a hob as a cutting tool, it is possible to manufacture a variety of gears, such as spur gears, helical gears, and worm wheels. FIG. 3B and FIG. 3C show an example of a hob 14A. The hob 14A has a cylindrical boss portion 15 and a plurality of cutting edges 16 provided on the outer circumferential surface of the boss portion 15. The plurality of cutting edges 16 are provided at predetermined intervals and in a spiral shape around the entire circumference of the boss portion 15. The hob 14A has a right-handed twist and a left-handed twist, which have different twist directions of the cutting edges 16.

[0051] In this way, the CNC vertical hobbing machine 60 can manufacture a variety of gears. By positioning and fixing the support plate 24 in the operating direction centered on the imaginary line F2 and fixing the swivel base 25 at a predetermined position in the direction along the imaginary line G1, a variety of gears, such as spur gears, helical gears, straight bevel gears, and spiral bevel gears, can be manufactured.

[0052] For example, in machining a spur gear or straight bevel gear, the rotation speed of the machining tool and the rotation speed of the workpiece are synchronized so that one tooth can be formed on the workpiece during one rotation of the machining tool around the imaginary line C1. That is, when cutting a spur gear or straight bevel gear having 10 teeth on the outer periphery, the workpiece is rotated at a rotation speed at which the workpiece rotates 36 degrees while the cutting tool rotates once. In addition, the workpiece is rotated 36 degrees every time the machining tool completes one rotation, and the machining tool is moved in a direction along the imaginary line H1 every time the machining tool completes one rotation. By repeating the above steps, the cutting of one spur gear or straight bevel gear is completed. In addition, when manufacturing a worm wheel by cutting the workpiece with the machining tool, a step of operating the table 26 and the workpiece in a horizontal direction, for example, in the left-right direction in FIG. 4C, is performed.

[0053] On the other hand, when cutting a helical gear or spiral bevel gear with 10 teeth (10 teeth), the rotational speed of the work is controlled so that the work rotates once per one rotation of the cutting tool, and the work is cut by the cutting tool. Furthermore, by repeating the process of moving the cutting tool in the direction along the imaginary line H1 every time one rotation of the cutting tool is completed, it is possible to machine a helical gear or spiral bevel gear with 10 teeth all around, each of which is right-handed or left-handed. The amount by which the cutting tool is moved in the direction along the imaginary line H1 is determined according to the tooth width of the gear to be manufactured.

[0054] An example of the technical meaning of the matters described in this embodiment is as follows. The CNC vertical hobbing machine 60 is an example of a gear cutting device. The virtual line F1 is an example of a first virtual line. The virtual line C1 is an example of a second virtual line. The virtual line F2 is an example of a third virtual line. The virtual line G1 is an example of a fourth virtual line. The virtual line B1 is an example of a fifth virtual line. The virtual line H1 is an example of a sixth virtual line. The collet spindle 22 is an example of a work support part. The cutter 14 and the hob 14A are examples of cutting tools. The arbor 42 is an example of a cutting tool support part. The support plate 24 and the swivel table 25 are examples of a first movable part. The support table 44 is an example of a second movable part. The lift table 45 and the guide rail 47 are examples of an operating mechanism. The table drive mechanism 70 is an example of a horizontal operating mechanism. Fig. 4C is an example of a "plane viewed from directly above the actuation mechanism in the vertical direction". Figs. 4A and 4B are examples of a "plane perpendicular to the third imaginary line". Figs. 5 to 12 are each an example of a "plane perpendicular to the fourth imaginary line".

[0055] The present embodiment is not limited to those disclosed using the drawings, and various modifications are possible without departing from the spirit of the present embodiment. For example, in the present embodiment, the specifications of the gears can be set arbitrarily. [Industrial Applicability]

[0056] This embodiment can be used as a gear cutting device that cuts a workpiece to manufacture a variety of gears. [Explanation of symbols]

[0057] 14... cutter, 14A... hob, 22... collet spindle, 24... support plate, 25... swivel table, 42... arbor, 44... support table, 45... lift table, 47... guide rail, 60... CNC vertical hobbing machine, 70... table drive mechanism, B1, C1, F1, F2, G1... virtual line, H1... movement trajectory

Claims

1. A gear cutting apparatus including: a workpiece support portion that supports a workpiece rotatably about a first imaginary line; and a cutting tool support portion that supports a cutting tool for cutting the workpiece rotatably about a second imaginary line, a first movable portion that operably supports the work support portion in a circumferential direction centered on a third virtual line and stops the work support portion at a predetermined position in the circumferential direction centered on the third virtual line; a second movable portion that supports the cutting tool support portion so as to be operable and stoppable about a fourth virtual line that intersects with the second virtual line; an actuation mechanism for actuating the cutting tool support in a vertical direction; having a gear cutting device in which the third virtual line and the fourth virtual line are arranged horizontally, and in a plane in which the operating mechanism is viewed from directly above in the vertical direction, the second virtual line and the third virtual line are arranged parallel to each other, the fourth virtual line is arranged on an extension of the first virtual line, the first virtual line and the third virtual line intersect at an angle of 90 degrees, and the second virtual line and the fourth virtual line intersect at an angle of 90 degrees.

2. The gear cutting apparatus according to claim 1, the first movable part can fix the workpiece support part at the predetermined position in a circumferential direction centered on the third virtual line, at a position where a fifth virtual line along a pitch cone of a spiral bevel gear as the workpiece and a sixth virtual line indicating a movement trajectory of the cutting tool are parallel to each other within a plane perpendicular to the third virtual line.

3. The gear cutting apparatus according to claim 1, A gear cutting apparatus, wherein the first imaginary line and the third imaginary line do not intersect within a plane perpendicular to the third imaginary line.

4. The gear cutting apparatus according to claim 1, The gear cutting apparatus further includes a horizontal actuation mechanism that actuates the first movable part in a direction along the fourth imaginary line.

5. The gear cutting apparatus according to claim 1, the second movable part supports the cutting tool support part so that the cutting tool support part can be operated and stopped around the fourth imaginary line within a plane perpendicular to the fourth imaginary line.

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