RU2323069C2 - Comb milling cutter - Google Patents

Abstract

FIELD: machine engineering, gear cutting tool for working hyperboloid gear wheels by copying method with periodic indexing.

SUBSTANCE: milling cutter includes annular turns. In order to increase useful life of worked gear wheels due to modifying cutting edges of milling cutter depending upon errors occurred at its manufacture and at engagement of two gear wheels, cutting edges near apex and near base of each annular turn of milling cutter are modified on portions consisting of 0.2 of turn height respectively by means of protuberance and flank of constant radius determined according to given formula.

EFFECT: increased useful life period of worked gear wheels.

5 dwg

Description

The invention relates to the field of engineering, in particular to a tool for cutting hyperboloid gears by copying with periodic division.

Known spur gear-cutting comb, the side cutting edges of which are made according to an ellipse curve (AC 75589. The method of profiling the teeth of spur gear cutting combs. Class 49d, 14, publ. 30.06.1949) - [1].

A worm mill is known for cutting cylindrical gears by the running method for subsequent grinding and shewing, the lateral cutting edges of which have a prominence and a flank made arcuate with a constant radius of curvature (S.N. Kalashnikov, A.S. Kalashnikov. Gear wheels and their manufacture. Moscow, Engineering, 1983, p.129) - [2]. The prominence and flank of the side cutting edges of this cutter are made from technological considerations to ensure that the grinding wheel and shaver exit the machining zone in the manufactured gear wheel during subsequent operations of the technological process.

Known as the closest analogue comb mill with ring turns for the manufacture of hyperboloid gears. The lateral cutting edges of this cutter are made rectilinear - (AC 1514515. A method of manufacturing a hyperboloid gears, IPC B23F 1/06, publ. 15.10.89, Bull. No. 38) - [3].

The disadvantage is that the lateral cutting edges of the comb mill are made without taking into account the influence of errors arising in the manufacture, assembly, operation of the gear pair and leading to a decrease in the durability of gear wheels made with such a mill.

The technical result to which the claimed invention is directed is to increase the durability of the gears made by such a comb mill by modifying the side cutting edges of the comb mill, depending on the errors encountered in the manufacture, operation of the gear pair.

The technical result is achieved by the fact that in a comb mill with ring turns for processing hyperboloid gears by the method of copying with periodic division, it is new that the side cutting edges of this mill are made with a prominence at the top of each turn and a flange at the base of each turn of the mill in sections 0, 2 heights of the turn, where the prominence and flank are made arcuate with a constant radius of curvature, depending on the errors that occur during the manufacture and operation of the gear pair. The radius of the arcuate sections of the side cutting edges of the comb mill is determined by the formula:

where R is the radius of the modified area in mm;

h ₁ - the height of the gear tooth in mm;

Δ _Σ is the value of the total error taken into account when modifying the lateral cutting edges of the comb mill in mm, equal to

Δ _Σ = Δ _w + f _f + Δ _xp + Δ _and ,

where Δ _W , f _f , Δ _xp , Δ _and are the components of the total error taken into account when modifying the side cutting edges of the comb mill, where:

Δ _W - parameter taking into account the roughness of the lateral surface of the teeth in mm;

f _f - tolerance for deviation of the profile in mm;

- параметр, учитывающий суммарный допуск двух равновероятных величин f_x и f_p в мм, где f_x - параметр, учитывающий допуск на предельное смещение средней плоскости зуба колеса в мм; f_p - параметр, учитывающий допуск на отклонение шага в мм;

- a parameter that takes into account the total tolerance of two equally probable values f _x and f _p in mm, where f _x is a parameter that takes into account the tolerance on the maximum displacement of the middle plane of the tooth of the wheel in mm; f _p - parameter taking into account the tolerance on the deviation of the pitch in mm;

параметр, учитывающий изгиб зуба под нагрузкой в мм, где F_t - окружная сила, приложенная на вершине зуба в Н;

- толщина зуба по хорде окружности впадин в мм; b - ширина зубчатого венца в мм.

a parameter that takes into account the bending of the tooth under load in mm, where F _t is the circumferential force applied at the top of the tooth in N;

- tooth thickness along the chord of the circumference of the depressions in mm; b - the width of the ring gear in mm.

- толщина зуба по хорде окружности впадин; F_t - окружная сила, приложенная на вершине зуба; F_n, F_r - нормальная и радиальная составляющие окружной силы F_t соответственно; фиг.3 - профиль модифицированных боковых режущих кромок гребенчатой фрезы, где: R - радиус дугообразных участков боковых режущих кромок гребенчатой фрезы; h_в - высота витка фрезы; Δ - глубина модификации боковых режущих кромок гребенчатой фрезы; фиг.4 - относительные положения нарезаемого колеса, воображаемого производящего колеса и инструмента; фиг.5 - сечение А-А на фиг.4.The invention is presented in figures 1-5, where figure 1 is a tool and profiles of the side cutting edges of a similar tool and the proposed tool; figure 1, a is a profile of the side cutting edges of the analog tool; figure 1, b is a profile of the side cutting edges of the proposed tool; figure 2 - errors taken into account when modifying sections of the side cutting edges of the comb mill; figure 2, a - parameter Δ _W , taking into account the roughness of the lateral surface of the teeth; figure 2, b - tolerance f _f on the deviation of the profile, where: h _l - the height of the gear tooth; figure 2, in - parameter f _x taking into account the tolerance on the maximum displacement of the middle plane of the tooth of the wheel; figure 2, g - parameter f _p taking into account the tolerance on the deviation of the step; figure 2, d - parameter Δ _and taking into account the bending of the tooth under load, where: h _l - the height of the tooth of the gear;

- the thickness of the tooth along the chord of the circumference of the depressions; F _t - circumferential force applied at the top of the tooth; F _n , F _r - normal and radial components of the circumferential force F _t, respectively; figure 3 is a profile of the modified lateral cutting edges of the comb mill, where: R is the radius of the arcuate sections of the side cutting edges of the comb mill; h _in - the height of the turn of the cutter; Δ is the depth of modification of the side cutting edges of the comb mill; 4 is the relative position of the cut wheel, an imaginary producing wheel and tool; figure 5 - section aa in figure 4.

Cutting gears with a comb cutter is as follows.

The machined wheel 1 and the tool 2 are informed of rotational movements around their axes O ₁ -O ₁ and O ₃ -O ₃ with angular velocities, respectively, ω _k and ω _f (Fig. 4). In addition, the wheel 1 is informed of additional rotation with an angular speed ω _pc around the axis O ₁ -O _{2 of} an imaginary producing wheel 3, the parameters of which are identical to the parameters of the processed wheel.

Gearing is performed at various interaxal distances between the machined 1 and imaginary producing 3 wheels, first at a distance equal to the diameter of the initial circumference of the machined wheel 1 in its throat section, and then at a distance equal to the sum of the radii of the initial circles in its end and throat sections. Several cavities 4 are simultaneously processed at once, while the axis of the tool 2 O ₃ -O _{3 is} set at an angle to the axis of the machined wheel 1 90 ° -β, where β is the angle of inclination of the teeth of the machined hyperboloid wheel 1 to its axis on the initial hyperboloid in section A- And, perpendicular to the direction of the tooth and passing through the interaxal perpendicular MM, one of the turns 5 of the tool 2 is set symmetrically relative to the interaxal perpendicular MM, and when moving from processing one group of depressions 4 to another, the machined wheel is turned on angle division, which is equal to 360 ° / n, where n - corresponds to the number of passages P _1, rounded to the nearest whole number and specific the formula P ₁ = z _a / k, wherein z _k - number of processed gearwheel 1, k - number turns 5 of the tool 2.

The outer diameter of the annular turns 5 of the comb mill 1 is made equal to the outer diameter of an imaginary producing wheel in its throat section. Step t _{to the} tool between adjacent turns (Fig. 5) is made equal to step t _{pc of} an imaginary producing wheel 3 in its normal section AA passing through the interaxal perpendicular MM.

An increase in the durability of the gears made by such a comb mill will be achieved due to the lack of initial edge contact on the head and leg of the teeth of the wheels at the moment of their engagement, and a small amount of clearance between the contacting surfaces on the head and leg of the teeth will allow contact over the entire height of the teeth after a short run-in.

=9 мм, h=6,75 мм.As an example, we give a calculation of the radius of the sections of the lateral cutting edges of a comb mill for cutting a hyperboloid gear (tolerances are assigned from the tables as for a worm gear of the 8th degree of accuracy). Initial data f _x = ± 0.053 mm, f _p = ± 0.02 mm, Δ _w = 0.007 mm, f _f = 0.014 mm, F _t = 4000 H, β = 45 °, b = 40 mm,

= 9 mm, h = 6.75 mm.

Calculation results

Δ _Σ = 0.007 + 0.014 + 0.0149 + 0.0152 = 0.0511 mm

Taking into account the influence of manufacturing errors and the operation of the gear pair, taken into account when modifying sections of the lateral cutting edges of the comb mill, a tool is obtained that allows to increase the durability of gears made by such a comb mill.

Claims (1)

A comb mill with ring turns for processing hyperboloid gears by the method of copying with periodic division, characterized in that the cutting edges at the top and bottom of each ring turn of the mill are modified in areas equal to 0.2 of the turn height, respectively, with a prominence and a flange of constant radius R, defined according to the formula

where h ₁ - the height of the gear tooth, mm; Δ _Σ = Δ _W + f _f + Δ _xp + Δ _and - the value of the total error taken into account when modifying the side cutting edges of the comb mill, mm; Δ _W - parameter taking into account the roughness of the lateral surface of the teeth, mm; f _f - tolerance for deviation of the profile, mm;

- a parameter that takes into account the total tolerance of two equally probable quantities f _x and f _p , mm;

- parameter taking into account the bending of the tooth under load, mm; f _x is a parameter that takes into account the tolerance on the maximum displacement of the middle plane of the tooth of the wheel, mm; f _p - parameter taking into account the tolerance on the deviation of the step, mm; F _t - circumferential force applied at the top of the tooth, H;

- tooth thickness along the chord of the circumference of the depressions, mm; b - the width of the ring gear, mm.

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