SU1152733A1 - Tapping die - Google Patents

Abstract

The METER, on the feathers of the intake cone of which the teeth are cut through a thread, characterized in that, in order to improve the threading accuracy and durability, the circumferential pitch between the front surfaces of two adjacent feathers, containing the first and last teeth cut, is increased by defined by the formula (.Z-OP Stny) - T iTTir — and the remaining circumferential steps between adjacent feathers are reduced by an amount determined by the formula R 6in C | where 7, is the number of feathers of the tap; R - thread pitch H - angle of the intake cone; “- back corner of the tap. t О1 к si СО САД

Description

The invention relates to metal working, namely to taps, and can be used mainly for machining threads in viscous and ductile materials.

Taps with an odd number of feathers are known, the teeth of which are on the gauge and intake part, i.e. along the whole threaded length of the tool are cut in a checkerboard pattern through a tooth. When machining threads with such taps in viscous and ductile materials, the threads of the thread formed by the holes have the ability to elastically deform to the side of the cut teeth of the tap in such a way that no tool is wedged between the tool teeth or the intake or calibrating part. In this case, the balance of forces lj is maintained on the pens of the tap.

However, such a tooth pattern cannot be extended to taps with an even number of feathers, as this would lead to the complete removal of the teeth on half the feathers. Therefore, for taps with an even number of feathers, the teeth are cut out according to other schemes, but at the same time the balance of cutting forces is disturbed due to the different cut thicknesses at the aerowayer, which significantly reduces the wear resistance of taps and impairs the accuracy of the thread they cut.

A tap with a thread-cutting pattern is the closest to the technical essence of the invention. This tap is simple to manufacture, since the teeth can be cut in one turn of the tap with multi-thread grinding wheels 1 o1 with double thread pitch.

The purpose of the invention is to improve the threading accuracy and durability of the tap with the teeth cut through the thread along the entire threaded length of the tool.

This goal is achieved by the fact that the tap, on the inlet cone feathers of which the teeth are cut through the thread along the entire threaded length, has a circumferential pitch between the front surfaces of two adjacent feathers containing the first and last teeth cut by an amount determined by according to the formula

(7; -OPsinCf iVz.eVno.

and the remaining circumferential steps between adjacent pens are made reduced by an amount determined by the formula

in t

uEj Z-sin o4

where “- the number of feathers of the tap P - the thread pitch; Cf - intake cone angle

tap, oi - the back angle of the tap.

FIG. 1 shows the tap, general view; in fig. 2 is the same, the cross section with altered circumferential steps between the front surfaces of adjacent feathers.

The tap includes an intake part 1, a calibrating part 2, a shank 3, and has four feathers with serial numbers 4-7 as they enter the hole. The tooth of the tap on the cutting and calibrating part, i.e. along the entire threading length of the tool, cut through a thread The remaining circumferential steps 2, €} between the front surfaces of adjacent feathers 4 and 5, 5 and 6, 6 and 7 are reduced compared to the nominal value of the circumferential mara l-z by the value

In operation, a tap with the specified values of circumferential steps between the front surfaces of feathers removes the teeth of the first feather with cut threads, not fivefold, but double the thickness of the cut.

The teeth of the remaining feathers also remove the double slice thickness. When the slice thicknesses are equal, the balance of cutting forces on the feathers is equalized and the tap in operation does not shift or is displaced by a significantly smaller value in the radial direction.

The use of the invention by leveling the thickness of the slice and cutting force on the feathers improves the accuracy of threading taps with cut threads and simultaneously increases the wear resistance of taps and their service life due to

Claims (1)

TAPER, on the feathers of the intake cone of which the teeth are cut through a thread, characterized in that, in order to increase the accuracy of the re-cutting and resistance, the circumferential step between the front surfaces of two adjacent feathers containing the first and last teeth cut on the thread is made increased by an amount determined by by the formula (Z - <) p- G> n & 8.- '-: ------- ·> ¹ Z · P and the remaining circumferential steps between adjacent feathers are made reduced by an amount determined by the formula P βίη ^{Λ 1} ~ Z-sineC where 7 is the number of tap feathers; P is the thread pitch; - angle of the intake cone; ⁰⁰ is the rear corner of the tap. (rig. 1