RU167740U1 - THREADED PLATE FOR CUTTING MULTI-START CONICAL THREAD ON PIPES - Google Patents

Abstract

The utility model relates to pipe production and can be used for cutting multiple tapered threads in threaded joints of oil assortment pipes. The threaded plate for cutting multiple conical threads has cutting teeth located on its calibrating part, the number of which is equal to the number of times the thread is cut, while all cutting teeth have the same shape and are located at a distance of the thread pitch from each other with a slope of the line passing through the tops of the teeth , which is determined by the difference in height between the vertices of adjacent teeth, based on the expression: A = Ρ × K / 2, where A is the difference in height between the vertices of the teeth, mm; Ρ - thread pitch, mm; K is the taper of the thread, while the thread pitch Ρ is measured parallel to the axis of the pipe thread. Using the utility model allows you to cut multi-tapered tapered thread of high accuracy and quality, which ensures the tightness, performance and operational stability of the threaded joint of oil assortment pipes while reducing the time of screwing and unscrewing. 1 ill.

Description

The utility model relates to pipe production and can be used for cutting multiple tapered threads in threaded joints of oil assortment pipes.

A threaded comb with a helical rear surface of cutting teeth is known, having a multi-starting rear helical surface and cutting teeth of the same profile, with which a multi-starting thread is cut with large screw angles, in particular crowns of multi-starting chevron wheels of self-braking gears (Aut. St. USSR No. 1013153, CL B23G 5/02, publ. 04.23.83). The disadvantage of the comb is the impossibility of cutting conical multi-thread with a small angle of elevation of the helix in the threaded joints of oil-grade pipes.

The closest in technical essence and the achieved results of the proposed utility model (prototype) is a comb (threaded plate) for cutting multiple threads, having cutting teeth located along the length of the intake and calibrating parts in sequentially joined packages, the length of each of which is equal to the course of the processed thread, shape cutting teeth varies from package to package, while within each package the number of cutting teeth is equal to the number of visits of the machined thread, and all the teeth have the same What are the shape and spaced thread pitch from each other (Pat. Russian №2214321, cl. B23G 5/02, publ. 20.10.2003). The disadvantage of the threaded plate of the prototype is its use for cutting multi-thread cylindrical threads and the inability to cut multi-thread conical threads of high accuracy in threaded pipe joints of oil grade.

The technical problem solved by the utility model is to create a threaded plate for cutting multi-taper tapered threads of high accuracy and quality, ensuring tightness, operability and operational stability of the threaded joint of oil assortment pipes while decreasing the make-up and unscrewing times.

The solution to the technical problem is due to the fact that in a threaded plate for cutting multi-tapered tapered threads on pipes with cutting teeth on the calibrating part, the number of which is equal to the number of starts of the cut thread, and all cutting teeth have the same shape and are located at a distance of the thread pitch from each other , the cutting teeth on the calibrating part of the threaded plate are inclined with a line passing through the tops of the teeth. The slope of the line is determined by the difference in height between the vertices of adjacent teeth, based on the expression:

where A is the height difference between the tops of the teeth, mm;

P - thread pitch, mm;

K is the taper of the thread,

wherein the thread pitch P is measured parallel to the axis of the pipe thread.

The essence of the utility model is illustrated by the drawing, where in FIG. 1 shows a profile of a threaded plate for cutting an external three-way tapered thread of a triangular profile on a pipe.

A threaded plate 3 cuts an external three-way tapered thread on a pipe 1 rotating at a speed ω, the end 2 of which is machined to a cone K. The threaded plate 3 consists of a fence 4 and a gauge of 5 parts. The cutting teeth 6 on the calibrating part 5 are located with the slope of the line passing through the tops of the teeth at a distance of the thread pitch P from each other, measured parallel to the axis 7 of the pipe thread 1. The shape, size of the profile and the relative position of the cutting teeth 6 correspond to the shape, size of the profile and mutual the location of the conical thread elements on the pipe 1. The number of cutting teeth 6 is equal to the number of thread starts p.

Due to the fact that the threaded plate 3 is designed for threading with a taper K, the cutting teeth 6 are positioned with a slope of the line passing through the tops of the teeth, which is determined by the difference in height between the vertices of adjacent teeth, based on expression (1). The accuracy of the execution of the elements of the thread profile depends on the thread-forming tool, therefore, the determination of the differences in height between the vertices of adjacent cutting teeth 6, based on a given taper K, instead of measuring the angle of inclination of the line passing through the vertices of the teeth provides a higher accuracy of their relative position, and, as a result , obtaining on the pipe of an oil assortment of conical multi-thread threads of higher accuracy and quality.

In the process of threading a pipe 1, rotating at a speed ω, the end 2 of which is grooved onto a cone with taper K, the longitudinal feed S is reported to the threaded plate 3, the value of which is determined by the formula:

where S is the longitudinal feed, mm / rev,

n is the number of visits,

P - thread pitch, mm,

which allows simultaneous cutting of the required number of thread starts with the corresponding number of cutting teeth 6 with high accuracy and quality.

The claimed technical solution was used when cutting double-thread tapered thread on experimental samples of tubing with a nominal diameter of 73 mm and a wall thickness of 5.5 mm from steel of strength group E, which underwent factory tests. A triangular profile thread was cut with a pitch of P = 2.54 mm with a taper of K = 1: 16 with a threaded plate with two cutting teeth on the calibrating part with a height difference between them A = P × K / 2 = 2.54 × (1:16 ) / 2 = 0.079 mm with a longitudinal feed S = n × P = 2 × 2.54 = 5.08 mm / rev.

Threaded connections made with high accuracy and quality have shown good performance and operational stability with amounts of make-up - unscrewing up to 20 cycles with a twofold reduction in make-up and unscrewing times due to the use of double-thread and withstood leak tests with a design pressure of 66.7 MPa in accordance with GOST 633-80.

Claims (1)

A threaded plate for cutting multi-tapered tapered threads on pipes with cutting teeth located on its calibrating part, the number of which is equal to the number of cuts of the thread being cut, and all cutting teeth have the same shape and are located at a distance of the thread pitch from each other, characterized in that the cutting teeth on the calibrating part of the threaded plate are located with a slope of the line passing through the tops of the teeth, which is determined by the difference in height between the vertices of adjacent teeth corresponding to the expression A = P ∙ K / 2, where A - difference in height between the peaks of adjacent teeth, mm; P - thread pitch, measured parallel to the axis of the pipe thread, mm; K is the taper of the thread.