JPH0663818A - Machining device for straight bevel gear - Google Patents

Abstract

PURPOSE:To provide a machining device which can machine tooth flanks of a gear and a gear which has a smooth mesh characteristics without using a dedicated cutting tool for each specification even if a gear is different in specification in machining the tooth flank of a straight bevel gear in an arc-like tooth shape. CONSTITUTION:An index shaft 3, which is rotatable around a horizontal axis, is provided on the turn table 22, which is rotatable around a perpendicular axis and is placed on a slide table 21, which is slidable in the direction of an X axis, and a gear W is clamped at the head of the index shaft 3. A grinding wheel 45 is movably held in the directions of a Y axis and Z axis, and the index shaft 3 and turn table 22 are made to rotate at a specified angle while moving the grinding wheel 45 along the root line of a tooth space Wa, and the contact section of a tooth flank to the grinding wheel is made to continuously move toward the tip of a tooth from the dedendum to vary the tangent in the direction of tooth depth at this contact section at a fixed rate so that the tooth flank may be machined in an arc-like tooth shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a machining apparatus capable of machining the tooth flank of an immediate bevel gear into an arc tooth profile.

[0002]

2. Description of the Related Art Immediate bevel gears used in a differential device of an automobile are processed by a lever cycle gear cutting method. This lever cycle gear cutting method, on the outer circumference of the rotating disk,
A plurality of broach blade-shaped cutting tools having concave arc-shaped cutting blades with the same radius centered on different points are provided around, and one by rotating the rotating disc in one direction while reciprocating in the tooth trace direction. The tooth groove is processed by cutting. The cutting tool that cuts the tooth surface is formed into a concave arc shape, and the processed tooth surface is processed into an arc tooth shape.

[0003]

In the above Lever cycle gear cutting method, when adjusting the shape of the tooth surface to be processed, it is necessary to adjust the shape and the mounting position of all of the plurality of cutting tools, and the processing is also performed. If the specifications of the gears are different, it is necessary to prepare a dedicated cutting tool for each specification. Further, in this lever cycle gear cutting method, since the tooth surface is formed by one rotation of the rotary disk around which the cutting tool is provided, a smooth tooth surface cannot be obtained, and the lever cycle gear cutting method is used. Gears do not have smooth meshing characteristics.

In view of the above problems, therefore, the present invention, when machining the tooth flank of an immediate bevel gear into an arcuate tooth profile, does not require the use of a dedicated cutting tool for each specification even if the gear specifications differ. An object of the present invention is to provide a processing device capable of processing a gear having good and smooth meshing characteristics.

[0005]

In order to achieve the above object, the present invention provides a rotary shaft for holding a direct bevel gear rotatably around a horizontal axis on a turntable which rotates around a vertical axis, Holding a rotary cutting tool in which concave arc-shaped cutting blades having a radius of curvature larger than the radius of curvature of the tooth surface of the gear are provided so as to be freely movable with respect to the gear, The turntable and the rotary shaft are moved such that the rotary blade is moved in the tooth trace direction of the gear, and the inclination of the tangent line along the tooth flank direction is changed at a constant rate in synchronization with the movement of the rotary blade. Has a circular arc tooth profile characterized by including control means for rotating the tooth surface into an arc tooth profile.

[0006]

Operation: While the rotary blade is moving along the root line, the turntable and the rotary shaft are operated so that the tooth surface continuously contacts the cutting blade from the root to the tip, and at this time, the tooth The tooth surface is formed into an arc shape by controlling the operation amounts of the turntable and the rotating shaft so that the inclination of the tangent line along the direction of the surface changes at a constant rate.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a work head 2 and a spindle head 4 are mounted on a bed 11 of a processing apparatus 1. The work head 2 includes a slide table 21 that is slidable in the X-axis direction and a turntable 22 that is placed on the slide table 21 and is rotatable about the vertical axis of the B-axis. Then, an index shaft 3 rotatable around a horizontal C-axis is projected from a bracket 23 erected on the turntable 22, and a gear W as a workpiece is clamped at the tip of the index shaft 3. I decided to do it.

On the other hand, the spindle unit 4 has the X
A column 41 slidable in the Y-axis direction orthogonal to the axis and a spindle unit 42 mounted on the column 41 and vertically movable in the Z-axis direction are provided. Then, a grindstone holder 44 is attached to the spindle shaft 43 of the spindle unit 42.
The grindstone 45 is attached via. The whetstone 4
As shown in FIG. 2, a concave arc-shaped grinding portion 46 having a radius r and serving as a cutting edge is provided in a pair on the left and right sides of the peripheral edge of the groove 5.

When the tooth groove Wa of the gear W is processed by the grindstone 45, the B axis is rotated so that the C axis, which is the rotation axis of the index shaft 3, is parallel to the X axis. The whetstone 45 is once moved to a position where the center of the whetstone 45 in the width direction is vertically above the axis of the C-axis (the position indicated by A in the figure). Further, the B axis is rotated so that the center of the tooth groove Wa in the groove width direction is also positioned vertically above the axis of the C axis, and the grindstone 45 is moved from the large end portion Wc side of the tooth groove Wa as shown in FIG. Then, the spindle unit 42 is lowered along the Z-axis, and the slide table 21 is moved in the X-axis direction in conjunction therewith to move the grindstone 4 as a relative motion with respect to the gear W.
5 is moved toward the small end portion Wd in the tooth trace direction.

Further, as shown in FIG. 4, the C-axis is rotated by a predetermined angle in conjunction with the movement of the grindstone 45 toward the small end Wd side, and the B-axis is rotated to move the gear W to the bottom line Wb. Vertex W
The wheel W is rotated about e to shift the gear W to the state shown in W'and the grindstone 45 is offset along the Y axis.
At this time, the contact portion of the tooth surface Wf with the grinding portion 46 is shown in FIG.
The tooth surface Wf has a curved line indicated by a broken line, and this contact portion moves sequentially from the broken line a to the broken line c as the grindstone 45 moves, and the inclination of the tangent line in the direction of the brush at the contact portion is constant. Control so that the tooth surface W
The f is formed in an arc shape with a smaller radius of curvature and a larger pressure angle as it goes to the small end Wd. The VV cross section when the contact portion is in the state indicated by the broken lines a, b, and c is shown as (a), (b), and (c) in FIG. 5, respectively.

By the above steps, the tooth groove Wa is formed 1.
One of the pair of tooth surfaces has been machined, and the other tooth surface rotates the B axis and the C axis in opposite directions while feeding the grindstone 45 again from the large end portion Wc side to the small end portion Wd side. To process. Then, the process of the gear W is completed by performing this step for each tooth groove.

As shown in FIG. 6, the controller 5 for performing such control has a drive control section 51 for feedback controlling a servo motor (not shown) for operating each axis of the processing apparatus 1 and various set values. And an arithmetic unit 52 that calculates the relational expression of the operation amount of each axis and transfers the NC program created based on the relational expression to the drive control unit 51.

In the above embodiment, a grindstone is used as the cutting tool, but a milling cutter may be used for cutting.

[0014]

As is apparent from the above description, according to the present invention, even if the bevel gears of different models are used, the cutting tool can be replaced by appropriately changing the turning amounts of the turntable and the turning shaft. Instead, it can be processed into a desired arc-shaped tooth surface. Further, since a grindstone or a milling cutter can be used as a cutting tool, not only cutting but also grinding can be performed, and a gear having smooth meshing characteristics can be processed.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a processing apparatus according to the present invention.

FIG. 2 is a sectional view showing the shape of a grindstone.

[Fig. 3] III sectional view taken along the arrow

[Figure 4] View from arrow IV

FIG. 5 is a VV sectional view showing a change in a contact state between a grindstone and a tooth surface.

FIG. 6 is a block diagram showing the configuration of a controller.

[Explanation of symbols]

 1 Processing Device 2 Work Head 3 Index Shaft 4 Spindle Head 5 Controller 22 Turntable 45 Grinding Stone 51 Drive Control Section 52 Calculation Section W Gear Wa Groove Wb Bottom Width Wc Large End Wd Small End We Apex Wf Tooth Surface

Claims (1)

[Claims] 1. A rotary shaft for rotatably holding a bevel gear around a horizontal axis is provided on a turntable that rotates around a vertical axis, and the tooth surface of the gear has a radius of curvature larger than the radius of curvature along the direction of brush. Left and right concave cutting blades with a radius of curvature 1
The rotary blades provided around the pair are held so as to be freely movable with respect to the gear, the rotary blades are moved in the tooth trace direction of the gear, and the tooth surface of the tooth surface is synchronized with the movement of the rotary blade. A straight blade having an arcuate tooth profile characterized by including control means for rotating the turntable and the rotary shaft so as to shape the tooth flank into an arcuate tooth profile so that the inclination of the tangent line along the brush direction changes at a constant rate. Bevel gear processing device.