SU1092314A1 - Sealing taper-threaded joint - Google Patents

Abstract

SEALED CONIC THREADED CONNECTION containing female and male parts with metric tapered threads, screwed with tension on the top and bottom of the thread, characterized in that, in order to increase the tightness of the joint, the female parts are covered with the ratio of the lengths of thread sections from their faces. the main plane, equal to 1.6-2.0. Osnojena plane (L with th

Description

The invention relates to mechanical engineering, and more particularly to threaded connections of machine parts and threaded pipe joints.

A conical threaded connection is known, consisting of a coupling with an internal conical thread screwed onto the external conical thread of the pipe [1].

This compound is widely used in mechanical engineering for sealing the fuel, oil and water pipelines ^WHO-1 stuffy machines and machine tools.

However, the required tightness of the joints cannot be ensured. This is due to the fact that this compound does not provide a guaranteed tightness at the vertices ₁ us and troughs screwed threads.

The closest to the proposed technical essence and the achieved result is a conical threaded connection containing female and male parts with a metric conical 2 thread, screwed with an interference fit on the tops and troughs of the thread [2].

The ratio of the lengths of the sections of the thread from their ends to the main plane in the known thread is taken to be less than unity. The specified ratio leads to the fact that with ² adverse ratios of tolerance fields, threads with an incomplete profile participate in the contact, and an interference fit at the tops and troughs of the threads occurs at the end of the part to be covered, where the first turn at the external thread is cut with a chamfer. The threads of the female part are usually cut with a cylindrical drill. When screwing a threaded pair near the main plane, a gap is formed along the vertices and sides of the thread profile, and the tightness of the connection is broken.

The aim of the invention is to increase the tightness of the conical threaded connection.

This goal is achieved by the fact that in a sealed conical threaded connection 4 containing female and male parts with a metric male thread, screwed with an interference fit on the tops and troughs of the thread, male and female parts are made with the ratio of the lengths of the sections of the thread from their ends to the base ⁴ plane equal to 1.6-2.

The drawing shows a sealed conical threaded connection.

The female part 1 with the cone angle of the average thread diameter is threaded onto the threaded portion _f of the male part 2c cone angle Vj average thread diameters.

The distances from the ends of parts 1 and 2 to the main plane of the thread are indicated, respectively, 1 _g and I,. P is the thread pitch.

With a ratio of 1 _X / E ₂ = 1.6-2 closure.

Threads occur on a larger cone, closer to the end of part 1. In this case, lower values of the ratio Е _х / Г _г correspond to a larger thread pitch P, and large values of the ratio ζ / Ε _{ζ to a} smaller thread pitch. Amount _x + E _z wherein ⁰ vatsya must remain constant and equal cone angles of A = 34 ^°, 48 ° ^{0 + I r} ', 3 ° 34'48 * that corresponds to the difference of average thread diameters in length E _x + E _g taking into account the maximum deviations.

The tightness on the tops and troughs of the screwed threads in the area of the main plane occurs along their full profile, there are no gaps in the threaded connection, which ensures the tightness of the conical threaded connection. The closure of the threads in the area of the main plane on the larger cone also contributes to a more uniform distribution of the load over the turns in the conical threaded connection when it is tightened and, as a result, a more uniform distribution of the contact pressure over the turns of the thread along the make-up length. The radial pressure from the interference on the threads is reduced, which eliminates galling and jamming in the threaded connection (which occurred when the threads were closed on a smaller cone), i.e. the initial specified requirements for the quality of contact surfaces are met.

The totality of the foregoing and the fulfillment of the basic tightness requirement for part of the coils in the elastic stage of deformation

Ved> Rkr>

where) to _L. —Contact pressure along the thread profile;

P _{cr - the} pressure of the medium in which a leak appears, favorably increases the tightness of the conical threaded connection.

For a thread-forming tool, for example, for a tap for cutting an internal tapered thread and for a die for cutting an external tapered thread, the distances of the threads at the tap and 1 _g at the die are also assigned from the ratio ^ / ^ = 1.6-4-2, and the cone angle is average the diameter of the tap thread is less than the same die angle, i.e. the angle of the cone of the average diameter of the thread of the tap should be set equal to 3 ° 34'48 ''^{£> and} - ', and the angle of the cone of the average diameter of the thread of the die 3 ° 34 ¹ 48' ^a ° ^g '

Claims (1)

SEALED CONICAL THREADED CONNECTION containing female and male parts with a metric conical thread, screwed with an interference fit on the top and bottom of the thread, characterized in that, in order to increase the tightness of the connection, the male and female parts are made with a ratio of the lengths of the thread sections from their ends to the main plane equal to 1.6-2.0.