JP2021010961A - Gear processing method - Google Patents

Abstract

To provide a gear processing method capable of preventing interference between an end part of a cutting edge of a gear cutting tool and a work-piece, and processing a gear.SOLUTION: A gear processing method that processes teeth of a gear of a work-piece with a gear cutting tool having a plurality of cutting edges on an outer periphery includes: a step (S12) of setting a central axis Ct of a gear cutting tool T to a state having a first angle (crossing angle) θ with respect to a central axis Cw of a work-piece W on a second plane S2; a step (S13) of setting the central axis Ct of the gear cutting tool T to a state having a second angle (angle of inclination) α with respect to the central axis Cw of the work-piece W on a third plane S3; and steps (S14, S15) of synchronizing the work-piece W with the gear cutting tool T, relatively moving the gear cutting tool T in the central axis Cw direction of the work-piece W with respect to the work-piece W, and processing teeth of the gear in the work-piece W.SELECTED DRAWING: Figure 11

Description

The present invention relates to a gear processing method.

In recent years, gear machining capable of high-speed machining has been desired from the viewpoint of cost, and skiving machining as described in Patent Document 1 is known. The skiving process is a state in which the central axis of the gear cutting tool and the central axis of the workpiece have an intersecting angle in gear processing. Then, while rotating the gear cutting tool and the workpiece synchronously around their respective central axes, the gear cutting tool is relatively moved in the direction of the central axis of the workpiece. In the skiving process, each tooth groove portion of the workpiece is machined only once by the gear cutting tool while the workpiece makes one revolution.

In this skiving process, the gear cutting tool is advanced straight to a preset end position in the feed direction to form a gear to a predetermined axial position of the workpiece. At this time, since the gear cutting tool has an intersecting angle with respect to the workpiece, the tip of the cutting edge of the gear cutting tool protrudes in the feed direction from the axial position where the gear is formed in the workpiece. .. Therefore, depending on the shape of the workpiece, the tip of the cutting edge of the protruding gear cutting tool may interfere with the workpiece.

Patent Document 2 describes a skiving processing method in which an annular groove in which the tip of a cutting edge of a gear cutting tool is accommodated is formed in advance on the end surface of a workpiece. As a result, even if the tip of the cutting edge of the gear cutting tool protrudes in the feed direction from the axial position where the gear is formed in the workpiece, it is accommodated in the annular groove, so that the cutting edge of the protruding gear cutting tool Interference between the tip and the workpiece can be prevented.

However, this skiving processing method has a problem that it cannot cope with the case where an annular groove cannot be formed on the end face of the workpiece. Patent Document 3 describes a skiving processing method for changing the crossing angle. According to this skiving processing method, it is possible to prevent interference between the tip of the cutting edge of the gear cutting tool and the workpiece.

Japanese Unexamined Patent Publication No. 2012-171020 JP 2015-89600 JP-A-2018-79558

In the gear processing method by skiving described in Patent Document 3 described above, in order to prevent interference between the tip of the cutting edge of the gear cutting tool and the workpiece, the crossing angle tends to be small, and various gears are used. There is a problem that it cannot be processed depending on the original. Further, in order to prevent interference between the tip of the cutting edge of the gear cutting tool and the workpiece, there is a problem that the gear cutting tool tends to have a small diameter, the tool life is shortened, and the machining accuracy is deteriorated.

An object of the present invention is to provide a gear processing method capable of processing a gear by preventing interference between the tip of a cutting edge of a gear cutting tool and a workpiece.

The gear processing method for processing gear teeth on a workpiece according to the present invention is a gear processing method for processing gear teeth on a workpiece with a gear cutting tool having a plurality of cutting edges on the outer periphery. A first plane including the central axis of the gear cutting tool and the central axis of the workpiece is defined by making the central axis of the gear cutting tool parallel to the central axis of the workpiece, and the first plane includes the central axis of the gear cutting tool and the central axis of the workpiece. A second plane that is perpendicular to the center axis of the gear cutting tool and includes the center axis of the gear cutting tool is defined, and the center axis of the gear cutting tool that is perpendicular to the second plane and has a first angle (intersection angle) is set. Define the third plane to include.

The gear processing method includes a first angle setting step of setting the central axis of the gear cutting tool in the second plane so as to have the first angle with respect to the central axis of the workpiece, and the third plane. A second angle setting step of setting the central axis of the gear cutting tool to have a second angle (tilt angle) with respect to the central axis of the workpiece, and rotation of the workpiece around the central axis of the workpiece. A synchronous rotation step that synchronizes the rotation of the gear cutting tool with respect to the central axis of the gear cutting tool, and the work by moving the gear cutting tool relative to the workpiece in the direction of the central axis of the workpiece. The object is provided with a gear processing step for processing the teeth of the gear.

According to the gear machining method according to the present invention, since the central axis of the gear cutting tool is inclined with respect to the central axis of the workpiece, the tip of the cutting edge of the gear cutting tool is in the axial direction in which the gear is formed in the workpiece. The amount of protrusion from the position in the feed direction can be set small. Therefore, the gear can be machined by preventing the tip of the cutting edge of the gear cutting tool from interfering with the workpiece without reducing the diameter of the gear cutting tool. Therefore, the tool life can be improved and high-precision machining can be maintained.

It is a figure which shows the schematic structure of the gear processing apparatus. It is a figure which shows the double helical gear which has the 1st gear and the 2nd gear processed by the gear processing apparatus of FIG. It is a perspective view of the 1st gear cutting tool for machining the 1st gear of the double helical gear of FIG. It is a perspective view of the 2nd gear cutting tool for machining the 2nd gear of the double helical gear of FIG. FIG. 3B is a partial cross-sectional view of the first gear cutting tool (second gear cutting tool) of FIG. 3A (FIG. 3B) as viewed from a direction perpendicular to the central axis. It is the figure which looked at the arrangement state before making the crossing angle necessary for machining a work piece by the 1st gear cutting tool in the radial direction of a work piece. FIG. 4A is a view seen in the direction of the central axis of the workpiece. It is the figure which looked at the arrangement state after making the crossing angle necessary for machining a work piece by the 1st gear cutting tool in the radial direction of a work piece. FIG. 5A is a view seen in the direction of the central axis of the workpiece. It is a figure which looked at the arrangement state after having added the crossing angle and the inclination angle necessary for processing a work piece by the 1st gear cutting tool in the radial direction of the work piece which can discriminate the crossing angle. It is a figure which looked at the arrangement state after having added the crossing angle and the inclination angle necessary for processing the workpiece with the 1st gear cutting tool in the radial direction of the workpiece whose inclination angle can be discriminated. It is a figure which looked at the arrangement state after having added the crossing angle and the inclination angle necessary for machining a work piece by the 2nd gear cutting tool in the radial direction of the work piece which can discriminate the crossing angle. It is a figure which looked at the arrangement state after having added the crossing angle and the inclination angle necessary for processing the workpiece with the 2nd gear cutting tool in the radial direction of the workpiece whose inclination angle can be discriminated. If the tool blade of the first gear cutting tool does not have a clearance angle, the placement state after adding the offset angle, intersection angle, and inclination angle required when machining the workpiece with the first gear cutting tool is the diameter of the workpiece. It is a view in the direction. FIG. 8A is a view seen in the direction of the central axis of the workpiece. It is a flowchart for demonstrating the design method of the gear cutting tool used for a gear processing apparatus. When a gear tooth profile (broken line) when a gear cutting tool with an involute curved blade shape is machined with an inclination angle and when a gear cutting tool with a non-involute curve shape blade shape is machined with an tilt angle It is a figure which shows the tooth profile (solid line) of the gear of. It is a figure which shows the blade shape (broken line) of an involute curve shape, and the blade shape (solid line) of a modified non-involute curve shape in the cutting edge of a gear cutting tool. It is a flowchart for demonstrating the gear processing method.

(1. Configuration of gear processing device 10)
The configuration of the gear processing apparatus will be described with reference to the drawings. As shown in FIG. 1, the gear processing apparatus 10 has, for example, three straight shafts and two rotation shafts as drive shafts that change the relative positions and orientations of the workpiece W and the machining tool T. In this example, the gear processing device 10 has three orthogonal axes (X-axis, Y-axis, Z-axis) as straight-moving axes, and A-axis and B-axis as rotating axes. The A-axis is a rotation axis around the X-axis line in the reference state, and the B-axis is a rotation axis around the Y-axis line in the reference state. Further, the gear processing device 10 has a Ct axis capable of rotating the gear cutting tool T around its own central axis, and a Cw axis capable of rotating the workpiece W around its own central axis. That is, the gear processing device becomes a 7-axis machining center including the Ct axis and the Cw axis.

The gear processing device 10 includes a tool spindle 11 that supports the gear cutting tool T and is rotatable, and a workpiece spindle 12 that is rotatable by supporting the workpiece W and is movable relative to the tool spindle 11. Further, a tool magazine 13 capable of accommodating the gear cutting tool T, a tool changing device 14 for exchanging one gear cutting tool T with respect to the tool spindle 11 for another gear cutting tool T, and operation control of gear tooth machining. The control device 15 and the like are provided.

The tool spindle 11 rotatably supports the gear cutting tool T around the central axis (Ct axis) of the gear cutting tool T via a gripping device 11a on a bed (not shown). Further, the tool spindle 11 can be moved in the X-axis direction and the Y-axis direction on the bed. Therefore, the gear cutting tool T can rotate around the central axis (Ct axis) of the gear cutting tool T, and can move in the X-axis direction and the Y-axis direction with respect to the bed.

The work spindle 12 rotatably supports the work W on the bed via the chuck 12a around the central axis of the work W (Cw axis). Further, the workpiece spindle 12 is supported on the bed by the tilt table 12b so as to be A-axis rotatable (tilt (tilted)), and on the bed by the turntable 12c so as to be B-axis rotatable.

The work spindle 12 supported by the tilt table 12b can move in the Z-axis direction on the bed. Therefore, the workpiece W can rotate around the central axis Cw of the workpiece W, and can rotate around the A-axis, the B-axis, and the Z-axis with respect to the bed.

The control device 15 controls the Ct axis rotation around the central axis of the gear cutting tool T (tool spindle 11) and the Cw axis rotation around the central axis of the workpiece W (workpiece spindle 12), respectively, and the workpiece W (working). The A-axis rotation and the B-axis rotation of the main spindle 12) are controlled, respectively. Further, the movement of the gear cutting tool T (tool spindle 11) in the X-axis direction and the Y-axis direction is controlled, and the movement of the workpiece W (work spindle 12) in the Z-axis direction is controlled. It also controls the tool changing operation of the tool changing device 14. Here, in the following description, the A-axis rotation center is referred to as the axis A, the B-axis rotation center is referred to as the axis B, the Ct-axis rotation center is referred to as the axis Ct, and the Cw-axis rotation center is referred to as the axis Cw.

(2. Work W)
In the gear processing device 10 of this example, a case where a general double helical gear WG used for a speed reducer of an automobile shown in FIG. 2 is formed by skiving processing will be described as an example. The double helical gear WG includes a first gear G1 and a second gear G2 that is coaxial with the first gear G1 and is formed as an integral portion with a gap d. The first gear G1 and the second gear G2 are formed to have the same shape and symmetrical twist angles. The first gear G1 is formed by pushing with the first gear cutting tool T1 (see FIG. 3A). The second gear G2 is formed by pulling with a second gear cutting tool T2 (see FIG. 3B).

(3. Tooth cutting tool T)
As shown in FIG. 3A, the tool blade Tc1 of the first gear cutting tool T1 has a conical trapezoidal shape having a plurality of cutting blades Tcc1 on the outer periphery, and the tool shaft Ta1 of the first gear cutting tool T1 has a small diameter end surface Tb1. It is formed as an integral part. As shown in FIG. 3B, the tool blade Tc2 of the second gear cutting tool T2 has the same shape as the tool blade Tc1 of the first gear cutting tool T1, and the tool shaft Ta2 of the second gear cutting tool T2 has a large diameter end surface. It is formed as an integral part of Td2.

The shape of the cutting edge Tcc1 on the large-diameter end surface Td1 of the tool blade Tc1 of the first gear cutting tool T1 is formed in a non-involute curved shape in this example. Similarly, the shape of the cutting edge Tcc2 on the large-diameter end surface Td2 of the tool blade Tc2 of the second gear cutting tool T2 is formed in a non-involute curved shape in this example. Then, as shown in FIG. 3C, the cutting edge Tcc1 (Tcc2) is provided with a rake angle inclined by an angle γ with respect to a plane perpendicular to the central axis Ct on the large-diameter end surface Td1 (Td2) side. A front clearance angle inclined by an angle δ with respect to a parallel straight line is provided on the peripheral surface side of the tool. The cutting edge Tcc1 (Tcc2) has a twist angle inclined by β with respect to the central axis Ct when a straight line Le passing through the center of the blade streaks Te1 (Te2) on both sides is viewed in the radial direction.

(4. Outline of gear processing method)
Weight reduction of parts is required as an energy saving measure for automobiles, but in double helical gear WG, it is required to reduce the weight of parts by narrowing the gap d. However, when the gap d is narrowed in the double helical gear WG, when the first gear G1 is pushed by the first gear cutting tool T1, the tip of the cutting edge Tcc1 of the first gear cutting tool T1 becomes the second gear G2. May interfere with the cylindrical part where the is formed. Further, when the second gear G2 is pulled by the second gear cutting tool T2, the tip of the cutting edge Tcc2 of the second gear cutting tool T2 may interfere with the formed first gear G1. The gear processing method described below is a method in which the interference does not occur.

First, as shown in FIGS. 4A and 4B, the central axis Ct of the first gear cutting tool T1 and the central axis Cw of the workpiece W are made parallel. Then, the first plane S1 including the central axis Ct of the first gear cutting tool T1 and the central axis Cw of the workpiece W is defined.

Next, as shown in FIGS. 5A and 5B, a second plane S2 that is perpendicular to the first plane S1 and includes the central axis Ct of the first gear cutting tool T1 is defined. Then, in the second plane S2, the central axis Ct of the first gear cutting tool T1 is set to have an intersection angle θ (first angle) with respect to the central axis Cw of the workpiece W. This intersection angle θ is adjusted based on the twist angle of the teeth of the gear to be machined on the workpiece W and the twist angle of the first gear cutting tool T1.

Next, as shown in FIGS. 6A and 6B, a third plane S3 including the central axis Ct of the first gear cutting tool T1 which is perpendicular to the second plane S2 and has an intersection angle θ is defined. In the third plane S3, the central axis Ct of the first gear cutting tool T1 is set to have an inclination angle α (second angle) with respect to the central axis Cw of the workpiece W.

Then, the rotation of the workpiece W and the rotation of the first gear cutting tool T1 are synchronized, and the first gear cutting tool T1 is moved relative to the workpiece W in the direction of the central axis Cw of the workpiece W to move the first gear. Process G1 teeth. During the relative movement, the central axis Ct of the gear cutting tool T moves toward Ct2 in FIG. 6B. That is, the gear cutting tool T moves in the Y-axis direction. Here, the intercenter distance D between the gear cutting tool T and the workpiece W is the distance between the central axis Ct of the gear cutting tool T and the reference point Cw0 of the central axis of the workpiece W. That is, in the relative movement, the workpiece W is moved in the Z-axis direction while changing the intercenter distance D (based on the tooth bottom of the first gear G1). When the central axis of the gear cutting tool T is located at Ct2, the intercenter distance is D2. As a result, it is possible to prevent the tip of the cutting edge Tcc1 of the first gear cutting tool T1 from interfering with the cylindrical portion where the second gear G2 is formed.

Further, as shown in FIGS. 7A and 7B, the second gear cutting tool T2 arranges the first gear cutting tool T1 symmetrically. Then, the rotation of the workpiece W and the rotation of the second gear cutting tool T2 are synchronized, and the second gear cutting tool T2 is moved relative to the workpiece W in the direction of the central axis Cw of the workpiece W to move the second gear. Process G2 teeth. As a result, interference between the tip of the cutting edge Tcc2 of the second gear cutting tool T2 and the first gear G1 can be prevented.

When the front clearance angle δ is not formed in the first gear cutting tool T1, as shown in FIGS. 8A and 8B, the machining points Pc of the first gear cutting tool T1 and the workpiece W on the first plane S1. Is moved to a position (offset position) deviated by an offset angle φ in the circumferential direction of the workpiece W (machining point Pco). This is a common method used to ensure a front clearance.

Then, the rotation of the workpiece W and the rotation of the first gear cutting tool T1 are synchronized, and the first gear cutting tool T1 is moved relative to the workpiece W in the direction of the central axis Cw of the workpiece W to move the first gear. Process G1 teeth. As a result, it is possible to prevent the tip of the cutting edge of the first gear cutting tool T1 from interfering with the cylindrical portion where the second gear G2 is formed. Processing of the teeth of the second gear G2 is also possible.

(5. Design method of gear cutting tool)
Next, the design method of the first gear cutting tool T1 will be described with reference to the flowchart of FIG. Since the design method of the second gear cutting tool T2 is the same, the description thereof will be omitted.

First, point cloud data representing the workpiece W is created based on the specifications of the workpiece W (step S1). The specifications of the workpiece W are, for example, the number of teeth, the tooth length, the tooth thickness, the twist angle, etc.). For example, in the CAD system, by inputting the specifications of the workpiece W, point cloud data (CAD data) representing the workpiece W is created. Next, the inclination angle α is initially set (step S2). The initial value of the inclination angle α is 0 °. When the inclination angle α is 0 °, the state shown in FIGS. 5A and 5B is the initial state.

Next, an interference simulation capable of determining the presence or absence of interference between the workpiece W and the tip of the cutting edge of the gear cutting tool T is performed (step S3). The interference simulation uses point cloud data representing the workpiece W, external shape data of the cutting edge of the gear cutting tool T, an intersection angle θ, and an inclination angle α. Then, the interference simulation determines the presence or absence of interference between the gear cutting tool T and the second gear G2 in a state where the outer shape data of the cutting edge of the gear cutting tool T is located at the end point of the tooth profile processing of the first gear G1. The outer shape data of the cutting edge of the gear cutting tool T may be a circular shape representing a simple outer shape, or may be an uneven shape corresponding to the actual cutting edge. The intersection angle θ is a preset value based on the specifications of the workpiece W.

Then, when there is interference between the workpiece W and the tip of the cutting edge of the gear cutting tool T (step S4: No), the inclination angle α is changed by a minute angle (for example, 1 °) (step S5), and the step is performed. Return to S3 and perform the interference simulation again. Then, the inclination angle α is continuously changed until there is no interference.

In step S3, when there is no interference between the workpiece W and the tip of the cutting edge of the gear cutting tool T (S3: Yes), the inclination angle α at that time is determined (step S6). Next, the point cloud data of the cutting edge of the gear cutting tool T is created (step S7). The point cloud data of the cutting edge of the gear cutting tool T is determined based on the specifications of the gear cutting tool T determined based on the specifications of the workpiece W. Here, the point cloud data of the cutting edge of the gear cutting tool T is data having an involute-shaped tooth surface as the initial shape.

Next, a gear machining simulation for machining the first gear G is performed (step S8). In the gear machining simulation, the point cloud data representing the material of the work piece W and the point cloud data of the gear cutting tool T are initially arranged in a state having an intersection angle θ and an inclination angle α, and the gear cutting tool T is placed on the work piece W. It is moved relative to the central axis Cw direction of. As shown in FIG. 6B, the relative movement is an operation of moving the workpiece W in the Z-axis direction while changing the intercenter distance D.

Next, the tooth profile of the first gear G machined into the workpiece W in the gear machining simulation is compared with the design tooth profile of the first gear G1 to obtain the difference between the two. Then, based on the difference, the point cloud data of the cutting edge of the gear cutting tool T for processing the design tooth profile of the first gear G1 is corrected (step S9).

As shown in FIG. 10A, the design tooth profile GFD (shown solid line) of the first gear G1 and the tooth profile GFS (shown broken line) of the first gear G by gear machining simulation are different. For example, the point cloud data of the cutting edge of the gear cutting tool T is modified based on the tendency of the difference between the tooth profile GFD in design and the tooth profile GFS in the gear machining simulation. Since the point cloud data of the cutting edge of the gear cutting tool T had an involute curve shape at the initial stage, it has a non-involute curve shape after correction.

That is, as shown in FIG. 10B, the involute curve-shaped blade shape TFM (broken line in the figure) of the cutting edge of the gear cutting tool T at the initial stage of the simulation is modified to obtain the non-involute curve-shaped blade shape TFP (solid line in the figure). It is determined as the blade shape TFP of the cutting edge Tcc1 of the one-tooth cutting tool T1. This completes the design of the first gear cutting tool T1 capable of machining the tooth profile GFD of the first gear G1 in design.

(6. Gear processing method)
Next, the operation (gear processing method) of the control device 15 of the gear processing device 10 will be described with reference to the flowchart of FIG. It is assumed that the first gear cutting tool T1 is mounted on the tool spindle 11. Further, it is assumed that the second gear cutting tool T2 is housed in the tool magazine 13. Further, it is assumed that the work spindle 12 supports a work piece W provided with two cylindrical portions for forming the double helical gear WG.

The control device 15 has the specification data of the workpiece W, the specification data of the gear cutting tool T, the intersection angle θ, the machining conditions (tilt angle α) determined by the above-mentioned interference simulation and the gear machining simulation, and other machining conditions. Enter. Then, the control device 15 drives and controls a ball screw mechanism (not shown) for moving the tool spindle 11 and a drive motor to drive and control the first gear cutting tool T1 supported by the tool spindle 11 in the X-axis direction and the Y-axis direction. Move to each. Further, the ball screw mechanism and the drive motor shown in the drawing for moving the workpiece spindle 12 are driven and controlled to move the workpiece W supported by the workpiece spindle 12 in the Z-axis direction. Then, as shown in FIGS. 4A and 4B, the central axis Ct of the first gear cutting tool T1 supported by the tool spindle 11 and the central axis Cw of the workpiece W supported by the workpiece spindle 12 are parallel to each other. Is set to (step S11).

Then, the control device 15 drives and controls the drive motor (not shown) for the turntable 12c to rotate the workpiece W supported by the workpiece spindle 12 around the B axis. Then, as shown in FIGS. 5A and 5B, the central axis Ct of the first gear cutting tool T1 is set to have an intersection angle θ (first angle) with respect to the central axis Cw of the workpiece W (step S12, step S12, First angle setting process).

Further, the control device 15 drives and controls a drive motor (not shown) for the tilt table 12b to rotate the workpiece W supported by the workpiece spindle 12 around the A axis. Then, as shown in FIGS. 6A and 6B, the central axis Ct of the first gear cutting tool T1 is set to have an inclination angle (second angle) with respect to the central axis Cw of the first gear G1 (step S13, step S13, Second angle setting process).

Then, the control device 15 drives and controls the drive motor of the drawing for the rotation of the tool spindle 11 and the drive motor of the drawing for the rotation of the workpiece spindle 12 to drive and control the first gear cutting supported by the tool spindle 11. The workpiece W supported by the tool T1 and the workpiece spindle 12 is synchronously rotated (step S14, synchronous rotation step). Then, the ball screw mechanism and the drive motor for each movement of the tool spindle 11 and the workpiece spindle 12 are driven and controlled, and the first gear cutting tool T1 supported by the tool spindle 11 is supported by the workpiece spindle 12. The work is moved in the direction of the central axis Cw of the workpiece W, and control for machining the first gear G1 is started (step S15, gear machining step). As shown in FIG. 6B, the machining operation at this time is an operation of moving the workpiece W in the Z-axis direction while changing the intercenter distance D.

Then, the control device 15 determines whether or not the machining of the first gear G1 is completed (step S16), and when the machining of the first gear G1 is completed, the tool changing device 14 uses the first gear cutting tool T1. Is replaced with the second gear cutting tool T2 (step S17). Then, in the following, the same processing as the setting of the first gear cutting tool T1 is performed. That is, the central axis Ct of the second gear cutting tool T2 supported by the tool spindle 11 and the central axis Cw of the workpiece W supported by the workpiece spindle 12 are brought into a parallel state (step S18).

Then, the central axis Ct of the second gear cutting tool T2 is set to have an intersection angle θ (first angle) with respect to the central axis Cw of the workpiece W, and is set to have an inclination angle (second angle). (Steps S19, S20, first angle setting step, second angle setting step). Then, the second gear cutting tool T2 supported by the tool spindle 11 and the workpiece W supported by the workpiece spindle 12 are synchronously rotated (step S21, synchronous rotation step), and control for machining the second gear G1 is started. (Step S22, gear processing step). As shown in FIG. 7B, the machining operation at this time is an operation of moving the workpiece W in the Z-axis direction while changing the intercenter distance D. Then, the control device 15 determines whether or not the machining of the second gear G2 is completed (step S23), and when the machining of the second gear G2 is completed, all the processes are completed.

According to the gear machining method described above, since the central axis Ct of the first and second gear cutting tools T1 and T2 is inclined with respect to the central axis Cw of the workpiece W, the first and second gear cutting tools T1 and T1 The amount by which the tips of the cutting edges Tcc1 and Tcc2 of T2 protrude in the feed direction from the axial positions where the first and second gears G1 and G2 are formed in the workpiece W can be set small. Therefore, interference between the tip portions of the cutting edges Tcc1 and Tcc2 of the first and second gear cutting tools T1 and T2 and the workpiece W can be prevented without reducing the diameter of the first and second gear cutting tools T1 and T2. Then, the first and second gears G1 and G2 can be machined. Therefore, the tool life can be improved and high-precision machining can be maintained.

(7. Others)
In the above, the tool spindle 11 is configured to be movable in the X-axis direction and the Y-axis direction with respect to the workpiece spindle 12, and the workpiece spindle 12 is configured to be movable in the Z-axis direction with respect to the tool spindle 11. However, the tool spindle 11 and the workpiece spindle 12 may be configured to be relatively movable. The work spindle 12 is configured to be rotatable (tilt) around the A axis with respect to the tool spindle 11 and rotatable around the B axis, but the tool spindle 11 is A axis with respect to the tool spindle 12. It may be configured to be rotatable (tilt) around an axis parallel to the axis and rotatable around an axis parallel to the B axis. Further, in the workpiece W, the gear teeth are machined on the outer circumference of the cylindrical member, but the gear teeth may be machined on the inner circumference of the cylindrical member.

T1: First gear cutting tool, Tc1: Tool blade, Tcc1: Cutting edge, T2: Second gear cutting tool, Tc2: Tool blade, Tcc2: Cutting edge, S1: First plane, S2: Second plane, S3: Third plane, W: Work piece, G1: First gear, G2: Second gear, Ct: Center axis of gear cutting tool, Cw: Center axis of work piece, θ: Cross angle, α: Tilt angle

Claims (4)

A gear machining method in which gear teeth are machined on a workpiece with a gear cutting tool that has multiple cutting edges on the outer circumference.
A first plane including the central axis of the gear cutting tool and the central axis of the workpiece is defined by making the central axis of the gear cutting tool parallel to the central axis of the workpiece.
A second plane that is perpendicular to the first plane and includes the central axis of the gear cutting tool is defined.
A third plane including the central axis of the gear cutting tool, which is perpendicular to the second plane and has a first angle (intersection angle), is defined.
The gear processing method is
A first angle setting step of setting the central axis of the gear cutting tool in the second plane so as to have the first angle with respect to the central axis of the workpiece.
A second angle setting step of setting the central axis of the gear cutting tool in the third plane so as to have a second angle (tilt angle) with respect to the central axis of the workpiece.
A synchronous rotation step that synchronizes the rotation of the workpiece around the central axis of the workpiece with the rotation of the gear cutting tool around the central axis of the gear cutting tool.
A gear processing step of moving the gear cutting tool relative to the workpiece in the direction of the central axis of the workpiece to machine the gear teeth on the workpiece.
A gear processing method. The tooth profile of the gear has an involute curve shape.
The gear processing method according to claim 1, wherein the blade shape of the gear cutting tool is a non-involute curve shape. The gear processing method according to claim 1 or 2, wherein the gear processing step relatively moves the gear cutting tool and the workpiece with reference to the tooth bottom of the gear. The gear processing method according to any one of claims 1-3, wherein the gear includes a first gear and a second gear coaxially formed with the first gear as an integral portion.

Images