阅读说明：本技术 一种摆线齿锥齿轮端铣刀盘刀刃曲线优化方法 (Method for optimizing cutter edge curve of milling cutter disc at end of cycloid gear bevel gear ) 是由 郭文超 毛世民 于 2019-10-29 设计创作，主要内容包括：本发明公开了一种摆线齿锥齿轮端铣刀盘刀刃曲线优化方法,属于摆线齿锥齿轮加工领域。一种摆线齿锥齿轮端铣刀盘刀刃曲线优化方法包括下述步骤：1)根据齿轮副参数和刀具基本参数确定刀齿切削刃分段及各段曲线形式；2)确定大轮齿顶啮合起始边界；3)求步骤2)中大轮修形边界对应的一系列小轮理论齿面点,并将它作为小轮齿根理论修形边界；4)确定小轮刀齿齿顶修形高度或/和齿根修形高度；5)根据节点相切条件和齿形修形量,计算刀刃齿顶的曲率半径或/和齿根修形的曲率半径；6)确定刀尖圆角半径。该优化方法在保证齿面接触特性的前提下能够更合理的消除齿顶齿根接触。(The invention discloses a method for optimizing a cutter head edge curve at the end of a cycloidal-tooth bevel gear, and belongs to the field of processing of cycloidal-tooth bevel gears. A method for optimizing the cutter edge curve of a milling cutter disc at the end of a cycloid gear bevel gear comprises the following steps: 1) determining the cutting edge segmentation of the cutter teeth and the curve form of each segment according to the gear pair parameters and the basic parameters of the cutter; 2) determining the meshing starting boundary of the top of the big gear; 3) solving a series of theoretical tooth surface points of the small wheel corresponding to the shaping boundary of the large wheel in the step 2), and taking the theoretical tooth surface points as theoretical shaping boundaries of the tooth root of the small wheel; 4) determining the addendum modification height or/and the dedendum modification height of the small cutter teeth; 5) calculating the curvature radius of the addendum of the cutting edge or/and the curvature radius of the dedendum modification according to the node tangent condition and the tooth profile modification amount; 6) and determining the corner fillet radius of the tool nose. The optimization method can reasonably eliminate the tooth top and tooth root contact on the premise of ensuring the tooth surface contact characteristic.)

1. A method for optimizing the cutting edge curve of a milling cutter disc at the end of a cycloid gear bevel gear is characterized by comprising the following steps:

1) determining the cutting edge segmentation of the cutter teeth and the curve form of each segment according to the gear pair parameters and the basic parameters of the cutter;

the cutter tooth cutting edge comprises a main cutting edge, a tooth top profile, a tooth root profile, a cutter tip fillet and a cutter top edge, and the nodes of all sections of curves are tangent;

2) determining the meshing starting boundary of the top of the big gear;

3) solving a series of theoretical tooth surface points of the small wheel corresponding to the shaping boundary of the large wheel in the step 2), and taking the theoretical tooth surface points as theoretical shaping boundaries of the tooth root of the small wheel;

the theoretical tooth surface of the small wheel is a tooth surface of the small wheel which is completely conjugated with the tooth surface of the large wheel;

4) determining the tooth root modification height of the small flywheel cutter tooth or determining the tooth root modification height and the tooth top modification height;

5) calculating the curvature radius of the addendum of the cutting edge or/and the curvature radius of the dedendum modification according to the node tangent condition and the tooth profile modification amount;

6) and determining the corner fillet radius of the tool nose.

2. The method of claim 1 wherein said starting boundary of meshing of the top of the large gear tooth in step 2) is an upper boundary of the contact area on the face of the large gear tooth, and is a straight line parallel to the top of the tooth.

3. The method for optimizing the edge curve of the face milling cutter at the end of the cycloid gear according to claim 1, wherein the specific process of determining the addendum modification height of the pinion cutter tooth in step 4) is as follows:

solving a blade curve parameter set of an actual small gear tooth surface point corresponding to the small gear theoretical boundary point in the step 3), and taking the minimum value of the blade curve parameter set;

and the distance from the boundary to the cutter top line is the modification height of the addendum of the pinion cutter tooth.

4. The method for optimizing the cutter head edge curve of the bevel gear end milling cutter according to claim 1, wherein the specific process of determining the tooth root modification height of the pinion cutter tooth in step 4) comprises the following steps:

solving a small wheel tooth surface point blade curve parameter set corresponding to the theoretical modification boundary of the small wheel tooth crest, and taking the maximum value of the small wheel tooth surface point blade curve parameter set;

and the corresponding track of the maximum value on the tooth surface of the pinion is the actual modification boundary of the pinion tooth crest, and the distance from the actual modification boundary of the pinion tooth crest to the root of the cutter tooth is the modification height of the pinion cutter tooth root.

5. The method for optimizing the edge curve of a face milling cutter at the end of a cycloid gear according to claim 3 or 4, characterized in that the theoretical boundary of the small wheel is determined by a rotational projection to determine the actual modification boundary of the small wheel.

6. The method for optimizing the edge curve of a facing cutter at the end of a bevel gear of a cycloid gear as recited in claim 1, wherein the maximum value of the corner radius of the nose is found by trial and error based on the width of the received nose and the inclination angle of the top edge.

7. The method for optimizing the cutting edge curve of a face milling cutter at the end of a cycloid gear and a bevel gear according to claim 6, wherein the obtained maximum radius of the corner fillet satisfies the following requirements:

the maximum round corner radius of the tool nose can not cause excessive side cutting, namely the tool nose of the secondary cutting edge can not cut the tooth surface at the other side of the tooth socket during tooth cutting;

the maximum round corner radius of the tool nose is required to ensure that the tooth root transition curved surface cannot interfere with the tooth tops of the mating gears.

Technical Field

The invention belongs to the field of processing of a cycloid tooth bevel gear, and particularly relates to a method for optimizing a cutter edge curve of a milling cutter disc at the end of the cycloid tooth bevel gear.

Background

The cycloid tooth bevel gear is named after the tooth trace of the generating wheel is an extended epicycloid, and the tooth milling processing is carried out by adopting a constant-height tooth system and a Face-hobbing method (plane-hobbing) based on the principle of a plane generating wheel. The cycloid tooth bevel gear has three types: manufactured by Klingelnberg, germany, by orlikon, switzerland (Oerlikon) and by Gleason, usa, abbreviated as kreb, ohn and kreb, respectively.

The forming principle of the generating surface of the generating wheel of the imaginary plane of the cycloidal tooth bevel gear is as follows: the cutter head and the shaping wheel are respectively provided with a rounding circle, and the movement of the cutter head relative to the shaping wheel can be regarded as that the rounding circle of the cutter head rolls on the rounding circle of the shaping wheel in a pure rolling way, namely, the ratio of the diameter of the rounding circle of the cutter head to the diameter of the rounding circle of the shaping wheel is equal to the ratio of the number of cutter teeth of the cutter head to the number of teeth of the shaping wheel. When the cutter disc rolls on the rolling circle of the shaping wheel, the curved surface swept out by the cutting edge relative to the shaping wheel is the tooth surface of the shaping wheel, and the track of the point on the cutting edge in the plane of the shaping wheel is an extended epicycloid. The tooth surface of the processed gear is formed by winding the tooth surface of the forming gear. In actual processing, a machine tool rocking disc is used for representing a shaping wheel, cutter teeth of a cutter disc are divided into a plurality of groups, each group is provided with at least one inner cutter and one outer cutter, and a convex surface and a concave surface of a gear to be processed are respectively processed. In order to realize the local contact of actual requirements, a split double-layer cutter head with a very complicated mechanical structure is adopted, and an integral cutter head and a cutter inclining mechanism are adopted in an Australia system and a grid system, and the calculation of the integral cutter head and the cutter inclining mechanism is very complicated. In order to better control the tooth surface contact area, arc cutting edges are introduced into the three tooth systems to carry out tooth height direction modification, and tooth surface mismatch is more reasonable and controllable by combining with the drum shape in the tooth length direction.

In recent years, both the clinbeck and the gleisen develop six-axis full-numerical control bevel gear machine tools, a disc rocking mechanism is cancelled, a hard alloy sharp-toothed strip integral cutter head tool tilting method is adopted to process cycloidal-tooth bevel gears, and part of the machine tools can be dry-cut at high speed, but the clinbeck double-layer cutter head has a complex structure and is difficult to design and process, and only the clinbeck can be manufactured at present; the sharp-tooth cutter head of the Orlikang and the Grisson has high requirements on design and processing precision, and needs a special knife sharpener and a knife detecting machine. In practice, the cutting edge profile is usually made predominantly of straight lines and circular arcs, and in a few cases, the cutting edge profile is modified by adding a nose to avoid tip contact, and is usually made for a small wheel, which further reduces the strength of the small wheel root. The gear processed by the linear cutting edge is easy to generate tooth top and tooth root contact after installation error or load deformation, and even if a circular arc replaces a straight line, the contact condition of the tooth top and the tooth root can not be improved because the radius of the circular arc is large (more than 1000 mm). This phenomenon can be eliminated by using a nose of the tool tip, but it has two drawbacks: firstly, given the blindness of the convex angle and the modification quantity of the cutter top, a reasonable value is sought by repeated cutting tests; secondly, the convex angle of the cutter top is a section of straight line, and all the derivatives are not continuous at the joint of the convex angle and the main cutting edge, namely, the convex angle is a hard tooth surface modification shape and is unfavorable for tooth surface contact.

Disclosure of Invention

The invention aims to overcome the defect that the tooth surface contact characteristic cannot be ensured by solving the problem of tooth top and tooth root contact in the prior art, and provides a method for optimizing the edge curve of a milling cutter disc at the end of a cycloid gear bevel gear.

A method for optimizing the cutting edge curve of a milling cutter disc at the end of a cycloid gear bevel gear comprises the following steps:

1) determining the cutting edge segmentation of the cutter teeth and the curve form of each segment according to the gear pair parameters and the basic parameters of the cutter;

the cutter tooth cutting edge comprises a main cutting edge, a tooth top profile, a tooth root profile, a cutter tip fillet and a cutter top edge, and the nodes of all sections of curves are tangent;

2) determining the meshing starting boundary of the top of the big gear;

3) solving a series of theoretical tooth surface points of the small wheel corresponding to the shaping boundary of the large wheel in the step 2), and taking the theoretical tooth surface points as theoretical shaping boundaries of the tooth root of the small wheel;

the theoretical tooth surface of the small wheel is a tooth surface of the small wheel which is completely conjugated with the tooth surface of the large wheel;

4) determining the tooth root modification height of the small flywheel cutter tooth or determining the tooth root modification height and the tooth top modification height;

5) calculating the curvature radius of the addendum of the cutting edge or/and the curvature radius of the dedendum modification according to the node tangent condition and the tooth profile modification amount;

6) and determining the corner fillet radius of the tool nose.

Further, the meshing starting boundary of the big gear tooth top in the step 2) is an upper boundary of a contact area on the big gear tooth surface and is a straight line parallel to the tooth top.

Further, the specific process of determining the addendum modification height of the small-wheel cutter tooth in the step 4) is as follows:

solving a blade curve parameter set of an actual small gear tooth surface point corresponding to the small gear theoretical boundary point in the step 3), and taking the minimum value of the blade curve parameter set;

and the distance from the boundary to the cutter top line is the modification height of the addendum of the pinion cutter tooth.

Further, the specific process of determining the root shaping height of the pinion cutter tooth in the step 4) is as follows:

solving a small wheel tooth surface point blade curve parameter set corresponding to the theoretical modification boundary of the small wheel tooth crest, and taking the maximum value of the small wheel tooth surface point blade curve parameter set;

and the corresponding track of the maximum value on the tooth surface of the pinion is the actual modification boundary of the pinion tooth crest, and the distance from the actual modification boundary of the pinion tooth crest to the root of the cutter tooth is the modification height of the pinion cutter tooth root.

Further, the small wheel theoretical boundary determines a small wheel actual modification boundary through rotating projection.

Further, the maximum value of the radius of the corner fillet of the tool nose is obtained by a trial and error method according to the width of the tool nose and the inclination angle of the top edge.

Further, the obtained maximum tool nose fillet radius meets the following requirements:

the maximum round corner radius of the tool nose can not cause excessive side cutting, namely the tool nose of the secondary cutting edge can not cut the tooth surface at the other side of the tooth socket during tooth cutting;

the maximum round corner radius of the tool nose is required to ensure that the tooth root transition curved surface cannot interfere with the tooth tops of the mating gears.

Compared with the prior art, the invention has the following beneficial effects:

the method for optimizing the cutter head cutting edge curve at the end of the cycloidal-tooth bevel gear can reasonably eliminate the contact between the tooth top and the tooth root on the premise of ensuring the tooth surface contact characteristic, directly designs the contact area from the gear pair meshing principle, solves the blindness of the given cutter top salient angle and the modification amount in the prior method, does not need repeated trial cutting, and can reasonably eliminate the contact between the tooth top and the tooth root on the premise of ensuring the tooth surface contact characteristic in the design stage; the method for optimizing the edge curve of the end milling cutter disc of the cycloid-tooth bevel gear is not only suitable for optimizing the cycloid-tooth bevel gear, but also suitable for optimizing the cutting edges of the cutter teeth of other gears processed by the end milling cutter disc.

Drawings

FIG. 1 is a sectional optimization model of the cutting edge of the inner cutter tooth according to the present invention;

FIG. 2 is a theoretical meshing boundary of a large gear tooth crown according to the present invention;

FIG. 3 is a root relief boundary for a pinion according to the present invention;

FIG. 4 is a modified tip boundary of a small wheel according to the present invention;

FIG. 5 is a schematic view of the edge tangent and transition curve interference of the tool tip of the present invention; wherein, 5(a) is the side cutting of the cutter top, and 5(b) is the dryness of the transition curved surface;

FIG. 6 is a cutter tooth method profile optimization result of a left-handed small-wheel cutter head in the embodiment.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The invention is described in further detail below with reference to the accompanying drawings:

a method for optimizing the edge curve of a milling cutter disc at the end of a cycloid gear bevel gear comprises the following steps:

1) determining the cutting edge segment and the curve form of each segment

Referring to fig. 1, fig. 1 is a sectional optimization model of the cutting edge of the inner cutter tooth according to the present invention, wherein h is_TR、h_RRRespectively the addendum and dedendum modification heights of the blade, the corresponding modification amounts are respectively delta_TAnd delta_REpsilon is the angle of inclination of the top edge, w_tThe width of the knife top;

in a section of a cutter head method, a cutter tooth reference point is taken as an original point, a blade coordinate system SB-xyz is set, u is taken as a cutter edge curve parameter, the direction pointing to the cutter top is positive, and based on a geometrical relationship, a functional expression of each part of a cutter edge is as follows:

a) main cutting edge:

b) tooth top profile modification

c) Root shaping

d) Round corner of tool nose

In the above formula, the cutter profile angle α_n0Height h of reference point of cutter teeth_refAnd the radius of curvature ρ of the main cutting edge is determined by the position of the reference point and the contact characteristics at the time of tooth surface design;

the tooth form angle and arc length calculation formula of each node are as follows:

tooth profile angle of each node:

the arc length of each segment is as follows:

2) determining the starting boundary of meshing of the top of a large gear

Referring to FIG. 2, FIG. 2 illustrates theoretical meshing boundaries of the crown of a large gear tooth according to the present invention, defining an upper boundary of the contact area on the tooth surface of the large gear tooth, generally a straight line, Δ, parallel to the tooth tip_G1The distance from the starting boundary to the top of the big wheel;

3) calculating theoretical contouring boundary of pinion roots

Solving a series of small wheel theoretical tooth surface points corresponding to the large wheel shape trimming boundary in the step 2) and taking the small wheel theoretical tooth surface points as a small wheel tooth root theoretical shape trimming boundary, wherein the small wheel theoretical tooth surface is a small wheel tooth surface completely conjugated with the large wheel tooth surface, the small wheel tooth root shape trimming boundary is shown in fig. 3, a diamond line is the small wheel theoretical shape trimming boundary obtained by conjugating the large wheel shape trimming boundary, and an inverted triangle line is the small wheel tooth surface boundary actually drawn by a blade curve segmentation node;

4) determining the modification height h of the small gear tooth crest_TR

Solving a U parameter set U of actual small gear tooth surface points corresponding to the small gear theoretical boundary points in the step 3)_TRTake the minimum value u_minThe actual shaping boundary of the pinion tooth root is a series of corresponding points on the pinion tooth surface, see fig. 3, fig. 3 is the shaping boundary of the pinion tooth root of the invention, and the distance between the point and the cutter top line is h_TR；

5) Determining the tooth root modification height h of the pinion cutter_RR

Determining a theoretical modification boundary of the addendum of the small wheel by using the method in the step 2), and referring to fig. 4, wherein the fig. 4 is the addendum modification boundary of the small wheel, a solid line is the theoretical modification boundary of the addendum of the selected small wheel, and a diamond line is the actual boundary of the tooth surface of the small wheel marked by the cutting edge node of the cutter;

solving a small wheel tooth surface point U parameter set U corresponding to the boundary_RRMaximum value u of_maxThe corresponding track on the tooth surface of the small wheel is the actual shaping boundary of the tooth top of the small wheel, and the distance from the point to the root of the cutter tooth is h_RR；

6) Calculating the curvature radius rho of the modification of the tooth top and the tooth bottom of the blade according to the node tangent condition and the tooth profile modification amount_TRAnd ρ_RR；

7) Determining nose fillet radius ρ_ed

The radius of the tool nose fillet can not be directly calculated, and the following requirements are met: excessive side cutting cannot be caused, namely, the tool tip of the secondary cutting edge cannot cut the tooth surface on the other side of the tooth groove during tooth cutting, as shown in fig. 5(a), the tool tip side cutting is shown in fig. 5 (a); ensuring that the root transition surface cannot interfere with the tooth tips of the mating gear, see fig. 5(b), which is transition surface interference.