Gear tooth profile creation method

Abstract

To provide a gear tooth form generating method capable of increasing the rigidity of a tip of a skiving cutter during a skiving process to prolong a tool life.SOLUTION: This gear tooth form generating method for cutting a workpiece 102 of a plurality of paths through a skiving process to generate a gear sets a cutting amount larger on an obtuse angle side than that on a sharp angle side of a blade twist angle of a skiving cutter 100 during cutting of a plurality of paths by using the skiving cutter provided with a plurality of blades 108 having prescribed twist angles.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for creating a gear tooth profile by creating a gear on a workpiece through skiving machining.

Background Art

[0002] As a machining method for cutting gears, skiving machining is known. Skiving machining is performed while synchronizing the rotation of a skiving cutter, which is a cutting tool, with the rotation of a workpiece, which is the object to be machined, in a state where the rotation axis of the skiving cutter (cutter axis) is inclined with respect to the rotation axis of the workpiece (workpiece axis).

[0003] When machining a general spur gear by skiving machining, the shaft intersection angle formed by the cutter axis with respect to the workpiece axis is kept constant, and the skiving cutter and the workpiece are rotated synchronously. As a result, axial sliding occurs at the contact point between the skiving cutter and the workpiece. By utilizing this sliding, the interfering portion is shaved off from the workpiece. The skiving cutter is moved in the tooth width direction of the workpiece according to the amount of shaving, and a tooth groove (tooth profile) etc. is machined on the workpiece.

[0004] Patent Document 1 describes a control device for a machine tool. In this control device, based on the cutting amount in the radial direction of the workpiece and the amount of displacement in the circumferential direction of the workpiece from the previous machining path of a tool (angular cutter) that performs turning machining on the workpiece, the rocking amplitude and rocking direction capable of shredding the chips generated by the turning machining are calculated. And in the control device of Patent Document 1, it is stated that by relatively rocking and moving the workpiece and the tool based on the calculated rocking amplitude and rocking direction, the chips can be shredded.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] A skiving cutter has multiple blades with a predetermined helix angle. A skiving cutter is preferable if the cutting angle is adjusted to make the angles of the blades on both sides of the cutting edge equal, as this ensures even wear on both sides of the cutting edge. However, for skiving cutters used in small modules, machining the cutting angle is difficult, and if no cutting angle is provided at the cutting edge, wear becomes severe on the acute side of the helix angle at the cutting edge, shortening the lifespan.

[0007] Furthermore, the control device described in Patent Document 1 merely calculates the oscillation amplitude and direction that can shred the chips generated by turning, and causes the machine tool to perform oscillating cutting based on these calculations; it does not perform control that takes tool life into consideration.

[0008] In view of these problems, the present invention aims to provide a gear tooth profile creation method that can increase the rigidity of the cutting edge of a skiving cutter and improve tool life in skiving operations. [Means for solving the problem]

[0009] To solve the above problems, a typical configuration of the gear tooth profile creation method according to the present invention is a gear tooth profile creation method in which a gear is created by cutting a workpiece in multiple passes by skiving, characterized in that a skiving cutter equipped with multiple blades having a predetermined helix angle is used, and in the cutting of multiple passes, the amount of cutting on the obtuse angle side of the helix angle of the skiving cutter blades is made larger than the amount of cutting on the acute angle side.

[0010] In the above configuration, during skiving, where the rotation of the skiving cutter is synchronized with the rotation of the workpiece, the depth of cut on the trailing side (which contacts the workpiece later) is greater than the depth of cut on the leading side (which contacts the workpiece earlier) (which has an acute helix angle). As a result, during skiving, cutting is mainly performed on the obtuse helix side of the skiving cutter's blade, resulting in a negative rake angle. This increases the rigidity of the cutting edge and dramatically extends tool life.

[0011] The skiving cutter described above should ideally not have a cutting angle at the tip of the blade.

[0012] Thus, in skiving cutters, if a cutting edge with a helix angle is not provided at the tip of the blade, a significant acute and obtuse angle is created on the left and right sides of the cutting edge, resulting in severe wear on the acute side. In such cases, the present invention is particularly effective, as it can improve tool life by primarily cutting on the obtuse side of the helix angle of the skiving cutter blade. [Effects of the Invention]

[0013] According to the present invention, a method for creating gear tooth profiles can be provided that can increase the rigidity of the cutting edge of a skiving cutter in skiving operations and improve tool life. [Brief explanation of the drawing]

[0014] [Figure 1] This figure illustrates a method for creating gear tooth profiles in an embodiment of the present invention. [Figure 2] This figure shows a skiving process in which a workpiece is cut in multiple passes using the skiving cutter shown in Figure 1. [Modes for carrying out the invention]

[0015] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. The dimensions, materials, and other specific numerical values ​​shown in these embodiments are merely examples to facilitate understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals to avoid redundant explanations, and elements not directly related to the present invention are omitted from the illustrations.

[0016] Figure 1 is a diagram illustrating a gear tooth profile creation method in an embodiment of the present invention. The gear tooth profile creation method is a method of creating gears by cutting a workpiece 102, which is the object to be processed, in multiple passes using a skiving cutter 100 shown in Figure 1(a).

[0017] This gear tooth profile creation method is performed while synchronizing the rotation of the skiving cutter 100 with the rotation of the workpiece 102, and tilting the cutter axis 106, which is the rotation axis of the skiving cutter 100, with respect to the workpiece axis 104, which is the rotation axis of the workpiece 102.

[0018] Here, as an example, a typical spur gear is machined by skiving, as shown in Figure 1(a). In this case, the axial intersection angle between the cutter axis 106 and the workpiece axis 104 is kept constant, and the skiving cutter 100 and the workpiece 102 are rotated synchronously (skiving cutter 100 in the direction of arrow B, workpiece 102 in the direction of arrow A). This causes axial sliding of the workpiece 102 at the contact point between the skiving cutter 100 and the workpiece 102. This sliding is used to shave off the interfering portion from the workpiece 102. Depending on the amount shaved off, the skiving cutter 100 is moved in the tooth width direction of the workpiece 102 to machine tooth grooves (tooth profiles), etc., into the workpiece 102.

[0019] As shown in Fig. 1(b), the skiving cutter 100 includes a plurality of cutting edges 108 having a predetermined twist angle θa. Further, since the skiving cutter 100 is for small modules, it is difficult to process the engagement angle, and no engagement angle is provided at the tip (cutting edge 110) of the cutting edge 108. In such a case, in the skiving cutter 100, significant acute angle θb and obtuse angle θc occur on the left and right sides of the cutting edge 110, the wear of the cutting edge 112 on the acute angle side becomes severe, and the life is shortened.

[0020] Therefore, in the gear tooth profile generation method of the present embodiment, the cutting amount of the cutting edge 114 on the obtuse angle side is made larger than the cutting amount of the cutting edge 112 on the acute angle side. The cutting edge 112 on the acute angle side is the leading side that first contacts the workpiece 102 along the rotation direction of the skiving cutter 100 (see arrow B in Fig. 1(a)) among the cutting edges 108 of the skiving cutter 100, and is the acute angle side of the twist angle θa. Further, the cutting edge 114 on the obtuse angle side is the trailing side that later contacts the workpiece 102 along the rotation direction of the skiving cutter 100 among the cutting edges 108 of the skiving cutter 100, and is the obtuse angle side of the twist angle θa.

[0021] Fig. 2 is a diagram showing skiving machining for cutting the workpiece 102 in a plurality of passes using the skiving cutter 100 of Fig. 1. In the figure, a state where the cutting edge 108 of the skiving cutter 100 cuts into the workpiece 102 in a plurality of passes along the rotation direction (arrow B) of the skiving cutter 100 is shown in a plan view.

[0022] In the skiving cutter 100 shown in Fig. 2(a), single-edge cutting (flank infeed) is performed with the cutting edge 114 on the obtuse angle side, which is the trailing side of the cutting edge 108. In this single-edge cutting, by not cutting the tooth surface on the acute angle side (right tooth surface 116) cut in the previous pass in this pass, the cutting amount of the cutting edge 112 on the leading side, which is the acute angle side, is substantially zero.

[0023] On one hand, the cutting edge 114 on the obtuse angle side cuts the tooth surface on the obtuse angle side (left tooth surface 118) in multiple passes. In this way, in the skiving process shown in Fig. 2(a), the cutting depth of the cutting edge 114 on the obtuse angle side is made larger than that of the cutting edge 112 on the acute angle side.

[0024] In the skiving cutter 100 shown in Fig. 2(b), a modified single-edge cutting (modified flank infeed) is performed with the cutting edge 114 on the obtuse angle side, which is the trailing side of the blade 108. In this modified single-edge cutting, by modifying the cutting angle in multiple passes, for example, by about 1° to 5°, the right tooth surface 116A is slightly cut by the cutting edge 112 on the acute angle side. Thereby, the cutting marks on the right tooth surface 116A can be eliminated.

[0025] On one hand, the cutting edge 114 on the obtuse angle side cuts the left tooth surface 118A in multiple passes. In this way, in the skiving process shown in Fig. 2(b), the cutting depth of the cutting edge 114 on the obtuse angle side is made larger than that of the cutting edge 112 on the acute angle side.

[0026] Therefore, according to the gear tooth profile generation method of the present embodiment, in the skiving process, mainly by cutting with the cutting edge 114 on the obtuse angle side, which is the obtuse angle side of the twist angle, that is, the trailing side, of the blade 108 of the skiving cutter 100, the rake angle of the blade 108 becomes negative, so the rigidity of the cutting edge 110 is increased, and the tool life can be dramatically extended.

[0027] As described above, the preferred embodiments of the present invention have been described with reference to the accompanying drawings. Needless to say, the present invention is not limited to such examples. It is obvious that those skilled in the art can conceive of various modification examples or correction examples within the scope described in the claims, and it is naturally understood that they also belong to the technical scope of the present invention.

Industrial Applicability

Explanation of Signs

[0029] 100...Skiving cutter, 102...Workpiece, 104...Workpiece axis, 106...Cutter axis, 108...Blade, 110...Blade tip, 112...Acute cutting edge, 114...Obtuous cutting edge, 116, 116A...Right tooth surface, 118, 118A...Left tooth surface

Claims

[Claim 1] In a gear tooth profile creation method in which gears are created by cutting a workpiece in multiple passes using skiving, Using a skiving cutter equipped with multiple blades having a predetermined twist angle and no cutting angle at the tip, A method for creating a gear tooth profile, characterized in that, in the cutting of the multiple passes, the amount of cutting on the obtuse angle side of the helix angle of the skiving cutter blade is always greater than the amount of cutting on the acute angle side, while cutting the tooth surface and making cuts in the tooth height direction of the gear.

Images