RU2030260C1 - Thread-cutting head - Google Patents

Abstract

FIELD: metal working. SUBSTANCE: thread-cutting head has 2 housing with multiple-unit thread chasers made in the form of Z-shaped blocks. The chasers are placed in the housing with the possibility of the alignment turn. Cutting members are placed on the ends of the blocks. In this case the cutting members on some ends of the blocks form the inner producing surface. The cutting members on the other ends produce the outer helical surface with the direction opposite to that of the producing surface. EFFECT: facilitated manufacture and increased accuracy of the thread-shaping tool. 7 dwg

Description

 The invention relates to metalworking and can be used in the tool industry, as well as when cutting external threads manually and on machines with both a fixed and a rotating head.

 Known thread-cutting head with interchangeable combs, in which interchangeable cylindrical thread-cutting combs are installed in the housing on threaded supports and are fixed by means of movable elements. The disadvantages of the thread-cutting head include the low installation accuracy of interchangeable combs, which affects the accuracy of the cut threads.

 Closest to the technical nature of the proposed one is a thread-cutting head for cutting threads, comprising a housing with multi-element threaded combs placed therein with the possibility of adjustment, on the rear surfaces of the cutting elements of which a trailing angle is formed, the cutting edges of which are located at the same distance from the geometric axis of the head and Placed on a helical production line. In this case, the thread-forming elements are processed according to the technology, including the backing process.

 Design shortcomings are the complexity of the technology for profiling cutting elements and the low accuracy of the thread-forming tool due to regrinding. In addition, the optimal selection of the number of threaded combs is not ensured, which also leads to the implementation of complex manufacturing technology of the tool.

 The aim of the invention is to simplify manufacturing technology and improve the accuracy of the thread-forming tool.

где d_u - номинальный диаметр наружной винтовой поверхности;
d_1p - номинальный внутренний диаметр винтовой производящей поверхности;
α₃ - задний угол при вершине режущих элементов; причем режущие элементы на одних концах блоков образуют внутpеннюю винтовую производящую поверхность, а режущие элементы на других концах - наружную винтовую поверхность с направлением, противоположным направлению производящей поверхности, и с номинальным средним диаметром, заданным зависимостью:
d_2u=

, где d_2p - номинальный средний диаметр винтовой производящей поверхности;
i_u - число заходов резьбы, профилируемой на наружной винтовой поверхности;
i_p - число заходов винтовой производящей поверхности, при этом оптимальное количество гребенок определяется зависимостью
N =

+ 1
На фиг. 1 изображена резьбонарезная головка с поворотными многоэлементными резьбовыми гребенками на осях, выполненными в виде Z-образных блоков; на фиг. 2 - сечение А-А на фиг. 1; на фиг. 3 - резьбонарезная головка с резьбовыми гребенками, закрепляемыми в пазах с возможностью подстройки в радиальном направлении; на фиг. 4 - сечение Б-Б на фиг. 3; на фиг. 5 - схема установки резьбовой гребенки; на фиг. 6 - развертка винтовой производящей поверхности; на фиг. 7 - развертка наружной винтовой поверхности, профилируемой на инструменте.This is achieved by the fact that in a thread-cutting head designed for cutting external threads, comprising a housing with multi-part threaded combs placed therein with the possibility of adjustment, the rear surfaces of the cutting elements of which are located at the same distance from the geometric axis of the head and are placed on a helical production line, threaded combs are made in the form of Z-shaped blocks, at the ends of which there are cutting elements installed with an offset relative to the plane of symmetry of the head application, passing through the geometrical axis of the head by an amount
h =

where d _u is the nominal diameter of the outer helical surface;
d _1p is the nominal internal diameter of the screw producing surface;
α ₃ - the rear angle at the top of the cutting elements; moreover, the cutting elements at one end of the blocks form an internal screw producing surface, and the cutting elements at the other ends form an external screw surface with a direction opposite to the direction of the producing surface, and with a nominal average diameter specified by the relationship:
d _2u =

where d _2p is the nominal average diameter of the screw producing surface;
i _u is the number of thread starts profiled on the outer screw surface;
i _p is the number of runs of the screw producing surface, while the optimal number of combs is determined by the dependence
N =

+ 1
In FIG. 1 shows a thread-cutting head with rotary multi-element threaded combs on the axles, made in the form of Z-shaped blocks; in FIG. 2 is a section AA in FIG. 1; in FIG. 3 - thread-cutting head with threaded combs fixed in grooves with the possibility of adjustment in the radial direction; in FIG. 4 is a section BB in FIG. 3; in FIG. 5 is a installation diagram of a threaded comb; in FIG. 6 - scan screw producing surface; in FIG. 7 - scan of the outer helical surface profiled on the tool.

 The thread-cutting head contains a cylindrical body 1 and a shank 2 for mounting in the machine spindle or in the device. In the housing 1, grooves 3 are made for positioning the threaded combs 4, made in the form of Z-shaped blocks. In the case of the location of the threaded combs on the axes 5 (Fig. 1, 2), holes are made in the housing 6. The axles 5 are fixed with nuts 7. In the case of the threaded combs 4 with the possibility of adjustment in the radial direction (Figs. 3 and 4), the combs 4 are made inclined bevels 8, with which wedges 9 interact, installed in the bores 10 of the housing 1 on the screws 11.

Желательно, чтобы отношение

было целым наименьшим числом. При большом значении указанного отношения значительно вырастают габариты инструмента.When profiling, the cutting elements at the ends of the threaded combs 4 are set protruding outside the housing 1 and rotated 180 ^about their working position. The combs 4 are fixed in the grooves 3 and a helical surface with a nominal average diameter d _{2u is formed} on them. Moreover, according to the known nominal average diameter d _{2p of the} producing helical surface, the number of its strokes i _p and the selected number of strokes i _{u of the} outer helical surface profiled on the tool combs, provided that the elevation angles of the helical line of the producing surface τ _p and profiled on the tool τ _u the nominal average diameter d _2u is determined by the following relationship:
d _2u =

It is desirable that the attitude

was the smallest integer. With a large value of the indicated ratio, the dimensions of the tool significantly increase.

To increase the resistance of the cutting edges is necessary to provide threaded combs obtain them in the operating position (i.e. when reinstalling a groove 180 ^{on the} relative position which the comb occupied when profiling adjustable setpoint angle α _3), which is achieved by moving the cutting blade elements relative to the plane of symmetry of the head passing through the geometric axis of the head, by the value of h (Fig. 5).

;
β₂= arccos

Преобразуем уравнение к виду
arccos

·

-

= 180^°- α₃ ,$ откуда h определяется зависимостью
h =

где d_u - номинальный диаметр наружной винтовой поверхности, профилируемой на режущих элементах;
d_1p - номинальный внутренний диаметр винтовой производящей поверхности.From the diagram (Fig. 5) it is obvious that
β ₁ + β ₂ = 180 ^o -α ₃ , where
β ₁ = arccos

;
β ₂ = arccos

We transform the equation to the form
arccos

·

-

= 180 ^° - α ₃ , $ from where h is determined by the dependence
h =

where d _u is the nominal diameter of the outer helical surface profiled on the cutting elements;
d _1p is the nominal internal diameter of the screw producing surface.

(N-1) tg τ_p
Положение этой же точки А, профилируемой на резьбовых гребенках на наружном диаметре d_2u, определяется зависимостью
Δu =

tg τ_u
Из равенства
Δ_p= Δ_u оптимальное количество резьбовых гребенок в инструменте определяется зависимостью
N =

+ 1
На режущей части резьбовых гребенок 4 выполнены заборный конус, определяемый угловым параметром φ, длиной l₃, и калибрующая часть l_k (фиг. 1).An external helical surface is profiled on the tool, in the opposite direction to the direction of the helical producing surface. Moreover, from the diagram (Fig. 6) of the screw producing surface, point A on the first thread on the comb j = N, where N is the number of combs in the tool, on the diameter d _{2p is} determined by the dependence
Δp =

(N-1) tg τ _p
The position of the same point A, profiled on threaded combs on the outer diameter d _2u , is determined by the dependence
Δu =

tg τ _u
From equality
Δ _p = Δ _{u the} optimal number of threaded combs in the tool is determined by the dependence
N =

+ 1
On the cutting part of the threaded combs 4 there is a sampling cone defined by the angular parameter φ, length l ₃ , and the calibrating part l _k (Fig. 1).

PRI me R. For cutting the right thread M18 x 1 - 89 with the parameters of the screw producing surface d _2p = 17.35 mm; d _1p = 16.917 mm; i _p = 1.

Based on the operating conditions of the tool, we assign the value of the back angle α ₃ = 10 ^о and the number of visits of the outer helical surface profiled on the tool, i _u = 4. The main parameters of the cutting part of the tool according to the derived dependences N = 5; h = 1.19 mm; d _2u = 69.4 mm.

 The proposed thread-cutting head is easier to manufacture due to the fact that when profiling the cutting part of the threaded combs, the thread grinding operation is used instead of the backing operation. When sharpening the tool along the front surface, the accuracy of the profile of the cutting elements of the tool remains high due to the fact that the profile represents a helical surface that is not hardened. In this regard, the costs of manufacturing the tool and its subsequent operation are reduced. Tool life is enhanced by providing optimal trailing angles on the cutting elements of threaded combs.

Claims (1)

A THREADING HEAD designed for cutting external threads, comprising a housing with multi-element threaded combs placed therein with the possibility of adjustment, with a rear corner formed on the rear surfaces of the cutting elements and the cutting edges located at the same distance from the head geometric axis and placed on a helical production line characterized in that the threaded combs are made in the form of Z-shaped blocks, at the ends of which with an offset relative to the plane of symmetry of the head, pr passing through the geometrical axis of the head, the cutting elements are arranged, wherein the offset value h is selected from the formula

where d _and is the nominal diameter of the outer helical surface;
d _{1 p} - nominal internal diameter of the screw producing surface;
α _s - the rear angle at the top of the cutting elements,
moreover, the cutting elements at one end of the blocks form an internal screw producing surface, and the cutting elements at the other ends form an external screw surface with a direction opposite to that of the internal producing surface and with a nominal average diameter d _{2 and} selected by the formula

where d _{2 p} is the nominal average diameter of the screw producing surface;
i _and - the number of threads on the outer screw surface;
i _p - the number of visits of the screw producing surface,
the optimal number N of combs is selected by the formula

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