RU2767547C1 - Tow clamp - Google Patents

Abstract

FIELD: transportation.

SUBSTANCE: invention relates to railway transport, particularly, to tow hitch clamps. Clamp comprises head part, rear part and two traction strips. Strips connect the head and rear support parts. Spherical surfaces are made at points of connection of traction strips with side and end surfaces of head part. Edges of the side surfaces of the head part directed inside the clamp are made along the radius.

EFFECT: increased service life of clamp.

3 cl, 4 dwg, 1 tbl

Description

The claimed invention relates to railway transport, in particular to the designs of traction clamps for couplers.

A traction clamp is known [Patent for utility model RU 200822 U1 dated 11/12/2020], containing a head part, a rear support part, an upper and lower traction strip connecting the head and rear support part of the clamp, while the rear support part of the clamp is made with guide elements made protruding relative to the base metal of the rear support part of the traction clamp.

Also known is a traction clamp according to GOST 32885-2014 “Cast parts for coupling and automatic couplers of railway rolling stock. General specifications" version 1, containing the head part, the rear support part, the upper and lower traction strips connecting the head and rear support parts of the clamp, while the side surfaces of the head part are rectangular in shape and have traction strips with side and end surfaces at the junctions the head part of the transition sections connecting adjacent surfaces at angles close to perpendicular.

This design is chosen as a prototype for the claimed invention.

The disadvantage of the above structures is the presence of stress concentrators due to the uneven distribution of shock loads in the head of the clamp, which occurs during the operation of the automatic coupler of a freight car, which leads to a decrease in the strength characteristics of the traction clamp.

The problem to be solved by the invention is to create a design of the traction clamp, which makes it possible to increase the strength characteristics of the clamp and increase the intended service life due to improved stress distribution.

The problem is solved by the fact that at the junction of the traction strips with the side and end surfaces of the head part, four spherical surfaces are made, while the edges of the side surfaces of the head part, directed into the collar, are made along the radius.

The essence of the invention lies in the fact that the clamp is traction, contains a head part, a rear support part and two traction strips adjacent to the head and rear support parts and connecting them to each other, also at the junction of the traction strips with the side and end surfaces of the head part, four spherical surfaces (A), while the edges of the side surfaces of the head part, directed into the inside of the clamp, are made along the radius (R).

The spherical surfaces are made along the radius in the range from 350 to 450 mm.

The radius R of the edges of the side surfaces is made in the range from 200 to
300 mm.

The essence of the claimed invention is illustrated by drawings:

Fig. 1 - Traction collar (general view);

Fig. 2 - Traction collar (isometry);

Fig. 3 - Fields of distribution of equivalent stresses in the head part of the traction clamp (view ¾ from above);

Fig. 4 - Fields of distribution of equivalent stresses in the head part of the traction clamp (view ¾ from below).

Traction clamp, containing the head part 1, the rear support part 2 and two traction bands 3 adjacent to the head 1 and rear support 2 parts and connecting them to each other. At the junction of the traction strips 3 with the side and end surfaces of the head part 1, four spherical surfaces (A) are made. The edges 4 of the side surfaces 5 of the head part 1, directed into the inside of the clamp, are made along the radius (R).

Spherical surfaces (A) are made along the radius in the range from 350 to 450 mm.

The radius (R) of the edges 4 of the side surfaces 5 is made in the range from 200 to 300 mm.

The traction clamp works as follows.

The good condition of the coupling equipment determines the safety of the movement of the train. During the movement of the train, during its stops and performing various maneuvers, the traction collar is constantly subjected to compressive and tensile shock loads transmitted from the automatic coupler. Longitudinal loads acting on the clamp can cause stress concentration in places of sharp changes in the configuration of the clamp elements. Such elements include sharp corners in the head part of the clamp, as well as straight sections of the edges of the side surfaces of the head part directed inside the clamp. As a result, there is an uneven distribution of shock loads in the head part when stresses are distributed over the clamp body. In this case, the material adjacent to the weakened place perceives additional forces. This can lead to a decrease in the strength of the clamp, as well as cracking and fracture. To reduce the stress concentration, it is necessary to ensure smooth transitions between the clamp elements and a more uniform distribution of the load on the clamp structure.

The retention of the strength of the traction clamp was confirmed by the strength calculation, which was carried out in accordance with the requirements of the "Standards for the calculation and design of railway carriages of the Ministry of Railways of 1520 mm gauge (non-self-propelled)" and GOST 33434 "Coupling and automatic coupling device of railway rolling stock. Technical requirements and acceptance rules. The stress state of the stirrup was assessed using the finite element method (FEM) in the ANSYS Workbench 2020 R1 finite element package. The clamp strength was assessed according to the following scheme:

- on the action of the maximum tensile force of the traction clamp during the coupling of freight cars P = 2.5 MN, which is transmitted to the lugs of the clamp from the roller and acts in the longitudinal direction.

As zones for measuring the values of equivalent stresses, the most loaded zones for the considered design mode were chosen. The distribution fields of equivalent stresses in the elements of the traction clamp under the action of design loads are shown in figures 3 and 4.

The technical result of the claimed invention lies in the fact that the implementation of four spherical surfaces (A) at the junction of the traction strips with the side and end surfaces of the head part along a radius in the range from 350 to 450 mm, as well as the execution of the edges of the side surfaces of the head part, directed towards inside the clamp, along the radius (R) in the range from 200 to 300 mm, allows you to more evenly distribute the longitudinal shock loads transmitted from the automatic coupler by eliminating sharp corners and creating smooth transitions between the clamp elements, which in turn allows you to reduce the stress concentrators that occur in clamp design during the movement of the train and reduce the likelihood of cracks and fractures during the warranty period, as well as increase the strength characteristics of the clamp and increase the intended service life, while reducing material costs as part of the reclamation activity.

The dimensions of the radii of the spherical surfaces and the dimensions of the radii of the edges of the side surfaces were chosen by the calculation method and tested on a prototype.

In support of this statement, Table 1 shows comparative data on the stresses that occur in the proposed design of the traction clamp and in the design of the traction clamp with sharp corners of the head. The value of stress reduction due to the use of the specified technical solution in the design of the traction clamp is also indicated.

Currently, design documentation has been developed for the claimed invention and comprehensive testing of prototypes is underway.

Claims (3)

1. A traction clamp containing a head part, a rear support part and two traction strips adjacent to the head and rear support parts and connecting them to each other, characterized in that four spherical surfaces are made at the junctions of the traction strips with the side and end surfaces of the head part , while the edges of the side surfaces of the head part, directed into the inside of the clamp, are made along the radius. 2. Traction clamp according to claim 1, characterized in that the spherical surfaces are made along the radius in the range from 350 to 450 mm. 3. Traction clamp according to claim 1, characterized in that the radius of the edges of the side surfaces is made in the range from 200 to 300 mm.

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