RU2715826C1 - Railway wheel - Google Patents

Abstract

FIELD: transport machine building.

SUBSTANCE: railway wheel comprises rim (1) with rolling surface (1.1) and crest (1.2), hub (2) with axial bore and disc (3) of curved shape with outer (3.1) and inner (3.2) surfaces forming bend in central part of disc (3) directed towards outer surface of wheel, and with central line (3.3) of disk axial section.

EFFECT: reduced level of residual deformations occurring under action of operational mechanical loads and thermal stresses from wheel heating at braking, reduced rigidity of structure in axial and radial directions, improved damping ability of wheel.

3 cl, 5 dwg, 2 tbl

Description

The invention relates to the field of railway transport and can be used as a wheel of railway freight cars.

A wheel for railway transport is known, comprising a rim, a hub and an inclined disk with radius transitions to the rim and the hub, the disk being radially made flat, with straight generatrices and inclined to the wheel axis at an angle of 71 ° - 75 ° (see RU 2085403 C1, 07.27.1997).

In this known wheel from the action of operational loads, a highly stressed state arises with an uneven distribution of internal stresses over the volume of the wheel due to the plane-conical shape of the disk. Insufficient fatigue strength reduces wheel service life and impairs driving safety.

Reducing the level of internal stresses caused by the action of operational loads, a higher margin of fatigue strength and a more even distribution of internal stresses over the volume of the wheel are observed in the construction of railway wheels with curved disks.

A railway wheel is known having a central plane perpendicular to the axis of rotation of the wheel, and including a rim, a hub and a curved disk formed by the outer and inner surfaces and made with a bend in the central part, the theoretical middle line of the transverse profile of the disk passes through point A located at the point of mating of the disk with the rim, point C, where the theoretical center line has a maximum displacement towards the outer surface of the wheel, and point B, located at the point of mating of the disk with dull, with points A and C offset from the central plane toward the outer surface of the wheel, and point B offset from the central plane toward the inner surface of the wheel, and the ratio of the thickness of the disk at point A to the thickness of the disk at point B is from 0.7 to 1 , 1, and the ratio of the thickness of the disk at point C to the thickness at point B is from 0.7 to 0.9 (see RU 2486063 C1, 06.27.2013).

A railway wheel is known that contains a rim, a disk and a hub, while the axial section of the disk is curved with a bend in the central part, and the center line of the axial section of the disk at its interface with the hub is displaced in the axial direction relative to the center line of the axial section of the disk at its mating with the rim towards the inner surface of the wheel, while the bend in the Central part of the disk is directed toward the outer surface of the wheel, and the specified amount of displacement is in the range of values 10 ÷ 25 mm. (see RU 2259279 C1, 08.28.2005). This railway wheel is taken as the closest analogue.

The technical problem of the known railway wheels is a significant axial and radial displacement of the wheel rim relative to the hub during braking during operation. The indicated displacement of the wheel rim arises as a result of the action of thermal stresses arising due to the friction of the brake pads on the surface of the wheel, while the heat concentration on the rim increases. From repeated and prolonged braking, this process has a cyclic nature of loading and leads to expansion of the metal in the radial and axial directions, which leads to high thermal concentrations of internal stresses in the wheel disk, especially in the area of mating of the disk and rim. In addition, there is a localization of internal stresses on the outer and inner surfaces of the disk at the interface between the disk and the rim and the disk with the hub, due to external loads from the railheads of the railway track and from the elements of the freight car. An increase in the total internal stresses can lead to the initiation of fatigue cracks leading to the destruction of the wheel.

The technical result of the invention is to reduce the level of residual deformations arising under the action of operational mechanical loads and thermal stresses from heating the wheel during braking, as well as to reduce the rigidity of the railway wheel structure in axial and radial directions and improve damping ability.

The technical result is achieved by the fact that the railway wheel contains a rim, a hub and a disk of a curved shape with outer and inner surfaces forming a bend in the central part of the disk, directed towards the outer surface of the wheel, and with a central line of the radial section of the disk, while the center line of the axial section the disk at the interface between the disk and the rim and at the interface between the disk and the hub is displaced in the axial direction relative to the middle of the hub towards the outer surface of the wheel. In contrast to the closest analogue, the central line of the axial section of the disk at the interface between the disk and the rim is offset from the place of its interface with the hub by a value of 26.0 to 42.0 mm, the central line of the axial section of the disk at the interface between the disk and the hub offset from the middle of the hub by an amount of 10.0 to 24.5 mm, while the outer surface of the disk is formed on the side of the rim and on the side of the hub with outer radius lines R1 and R2 directed toward the inner surface wheels, in the central part of the disk is formed by two sections of the central outer radius curves R3 and R4 directed towards the outer surface of the wheel and conjugated to each other, and also formed by intermediate outer radius curves R5 and R6 directed towards the inner surface of the wheel and mated with the corresponding edge and central outer radius curves, the inner surface of the disk is formed on the side of the rim and on the side of the hub by the edge inner radius curves R7 and R8 directed to a defense of the outer surface of the wheel, in the central part of the disk is formed by two sections of the central inner radius curves R9 and R10 directed towards the outer surface of the wheel and interconnected, and also formed by intermediate outer radius curves R11 and R12 directed towards the inner surface of the wheel and conjugated with corresponding boundary and central inner radius curves.

In particular cases of the invention, the edge outer radius curves R1 and R2 are made in the range of radii from 12 mm to 70 mm; boundary inner radius curves R7 and R8, made in the range of radii from 20 mm to 45 mm, the central outer and inner radius curves R3, R9, located on the side of the rim, made in the range of radii from 30 mm to 125 mm, the central outer and inner radius curves R4, R10 located on the hub side are made in the range of radii from 30 mm to 170 mm, intermediate outer radius curves R5, R11 are made in the range of radii from 30 mm to 230 mm and intermediate inner radius curves R6, R12 are made in the range of radii from 30 mm d 135 mm.

In special cases of the invention, the angle of inclination of the disk to the axis of the wheel is from 76.5º to 82.5º.

The combination of the indicated design features of the railway wheel, namely, the shape of the curved disk in terms of the magnitude and direction of the radii of the radius curves of its outer and inner surfaces, the relative position of the center line of the axial section of the disk relative to the hub at the characteristic points of the disk, the angle of inclination of the disk, contributes to a more uniform distribution in volume wheels of total internal stresses arising from the action of thermal and mechanical operational loads, reducing the concentration internal stresses at the junction with the rim disc and the hub, wherein the fatigue stresses occur, and reduces stiffness wheel design that increases the damping capability, which reduces the dynamic loading on the rails and elements of a goods wagon.

The invention is illustrated by graphic materials, which show:

in FIG. 1 - railway wheel, axial section passing through the axis of rotation of the wheel;

in FIG. 2 is a diagram of the movements of the crests of three-dimensional wheel models along the component of the displacement vector Uz;

in FIG. 3 is a diagram of applying a radial load at the ridge and equivalent deformations of three-dimensional wheel models;

in FIG. 4 is a diagram of a radial load application with offset from the ridge and equivalent deformations of three-dimensional wheel models;

in FIG. 5 is a diagram of the application of the combined load on the surface of the skating and comb and equivalent deformations of three-dimensional models of wheels.

The railway wheel (Fig. 1) contains a rim 1 with a skating surface 1.1 and a ridge 1.2, a hub 2 with an axial hole (not shown) and a disk 3 of a curved cross-sectional shape with an external 3.1 and internal 3.2 surfaces forming a bend in the central part of the disk 3, directed towards the outer surface of the wheel, and with a center line 3.3 of the axial section of the disk.

The disk 3 is formed by six interconnected sections, conventionally referred to as edge sections located at the interface between the disk 3 and the rim 1 and the hub 2, the central section located on the side of the rim 1, the central section located on the side of the hub 2, and intermediate sections, located between the edge sections and the corresponding central sections.

The outer surface of the disk 3 is formed on the side of the rim 1 and on the side of the hub 2 by the outer edge radius curves R1 and R2 directed towards the inner surface of the wheel, in the central part of the disk 3 by two sections of the central outer radius curves R3 and R4 directed towards the outer surface wheels and mating with each other, as well as intermediate outer radius curves R5 and R6, directed towards the inner surface of the wheel and mating with the corresponding boundary and central outer radius curves. The inner surface of the disk 3 is formed on the side of the rim 1 and on the side of the hub 2 by the edge inner radius curves R7 and R8 directed towards the outer surface of the wheel, in the central part of the disk 3 by two sections of the center inner radius curves R9 and R10 directed towards the outer surface wheels and paired with each other, as well as intermediate outer radius curves R11 and R12, directed towards the inner surface of the wheel and paired with the corresponding boundary and central inner ra diagonal curves. All radius curves forming the outer and inner surfaces of the disk 3 have tangent conjugation with each other.

Edge outer radius curves R1 and R2 are made in the range of radii from 12 mm to 70 mm; edge internal radius curves R7 and R8 are made in the range of radii from 20 mm to 45 mm. The central outer and inner radius curves R3, R9, located on the side of the rim, are made in the range of radii from 30 mm to 125 mm, R4, R10, located on the side of the hub, are made in the range of radii from 30 mm to 170 mm. The intermediate outer and inner radius curves R5, R11 are made in the range of radii from 30 mm to 230 mm and R6, R12 are made in the range of radii from 30 mm to 135 mm.

The outer surface of the disk 3, formed by the radius curves R1, R2, R3, R4, R5, R6, is consistent with the inner surface of the disk 3, formed by the radius curves R7, R8, R9, R10, R11, R12, through circles of diameters d1, d2, d3 d4, d5, inscribed in the thickness of the disk 3, with which the indicated outer 3.1 and inner 3.2 of the surface of the disk 3 are tangentially connected. The circles can be made equal to the diameter d1, d2, d3 d4, d5, or a variable diameter in the range from 15 to 30 mm.

The center line 3.3 of the radial section of the disk 3 from the side of the rim 1 coincides with the line 4 passing through the middle of the rim 1, and along the length of the disk 3 passes through three characteristic points, from which point A is located at the interface between the disk 3 and the rim 1, point C is located at the point of greatest bending of the disk 3, point B is located at the interface between the disk 3 and the hub 2. The center line 3.3 of the axial section of the disk 3 at the location of point A is displaced in the axial direction relative to the center line 3.3 of the axial section of the disk 3 at the point In the side surface of the outer wheel by an amount "a" of between 26.0 to 42.0 mm. The center line 3.3 of the axial section of the disk 3 at point B is displaced in the axial direction relative to the line 5 passing through the middle of the hub 2 by an amount “b” of 10.0 to 24.5 mm.

The angle of inclination "α" of the disk 3 to the axis O-O of the wheel is from 76.5º to 82.5º.

In order to simulate the operating conditions of both thermal and mechanical loads, computer modeling and comparative calculations were performed for the designs of wheel 1 (a wheel with a displaced curved disk having a U-shaped transverse profile with a bend to the outside of the wheel), wheel 2 (a wheel with an unshifted curved a disk having an s-shaped transverse profile) and the proposed wheel.

For a comparative assessment of the thermally deformed state (Fig. 2) on the rolling surfaces of 1.1 three-dimensional wheel models, the heat fluxes of convective heat exchange with the environment were set and the boundary conditions corresponding to the operational mode of braking were set: Current = 40 ° C, convective heat transfer coefficient is 1048 W / m ² K, the heat flux density vector is 241 kW. Due to heating of the surfaces of the wheels during imitation braking, the ridges 1.2 move along the component of the displacement vector Uz in the axial direction in the direction of increasing the distance between the side surface of the rail and the ridge 1.2 of the wheel.

The values of the displacements of the ridges of the known wheels and the proposed wheel arising from the action of various loading modes are presented in table 1.

Table 1

Crest movement Wheel type Prototype Wheel 1 Experimental wheel 2 Proposed wheel Uz, mm 8.1 13,4 4.3

As you can see, the smallest movement Uz, characterizing the displacement of the wheel rim relative to the hub during braking, showed the wheel of the proposed design. A smaller displacement Uz indicates lower values of thermal concentrations in the disk of the wheel, including in the area of mating of the disk and rim.

For a comparative assessment of the stress-strain state, three-dimensional models of loading were applied to three-dimensional models of the prototype wheel and the proposed wheel, simulating the most typical operating conditions:

1 - radial load Px with the application on the surface of the wheel at a distance s = 46 ÷ 49 mm from the inner surface of the rim by the value Px = 284 kN (Fig. 3);

2 - radial load Px with the application of the wheel 1.1 on the tread surface at a distance s = 69 ÷ 71 mm from the inner surface of the rim, Px = 284 kN (Fig. 4);

3 - combined load with the application of a radial load Px on the rolling surface 1.1 with an offset towards the ridge 1.2 and an axial load Py with application on the ridge 1.2, Px = 1.25R = 156.25 kN, Py = 0.7R = 87.5 kN where R is half the vertical static load acting from the side of the trolley on the rail (Fig. 5).

The indicated most characteristic and unfavorable load application variants must be taken into account when calculating the railway wheel for fatigue and static strength. In order to maintain strength characteristics, equivalent stresses do not exceed the permissible value, which is 160 MPa. The calculated mode of the radial load acting on the surface of the rim, is carried out to assess the cyclic strength of the wheels when moving along a straight section of the path. The design mode of the combined load, in which vertical forces act on the rolling surface in the circum-ridge zone, and lateral forces act on the crest, is required to evaluate movement along curved sections of the path.

The values of equivalent deformations of the known wheels and the proposed wheel arising from the action of various loading modes are presented in table 2.

table 2

Equivalent deformation of the wheel disc Wheel type Prototype Wheel 1 Experimental wheel 2 Proposed wheel Loading mode 1 (radial load applied to the ridge) Units,% 0, 07330 0,08089 0,07350 Loading mode 2 (vertical load applied with offset from the ridge) Units,% 0, 07375 0, 07212 0,07695 Load Mode 3 (Combined Load) Units,% 0.01016 0,00853 0.01162

As follows from a comparative analysis of the data in Table 2, the total equivalent strain of the proposed wheel is the highest, which indicates a relatively lower value of the rigidity of this design in the axial and radial directions.

Thus, the railway wheel of the proposed design allows to reduce residual deformations from thermal stresses that arise as a result of friction of the surface of the brake pads and the surface of the wheel during braking, as well as reduce the level of stiffness and improve damping capabilities while maintaining strength characteristics. Improved performance indicators can increase the wheel's resistance to destruction, increase its life, reduce dynamic load on the upper track structure and on unsprung elements of a freight car.

Claims (3)

1. A railway wheel containing a rim, a disk and a hub, while the axial section of the disk is curved with a bend in the central part, and the center line of the axial section of the disk at its interface with the hub is displaced axially relative to the center line of the axial section of the disk at its mating with the rim towards the inner surface of the wheel, while the bend in the Central part of the disk is directed towards the outer surface of the wheel, characterized in that the center line of the axial section of the disk in places the pairing of the disk with the rim is shifted relative to the place of its pairing with the hub by an amount "a", ranging from 26.0 to 42.0 mm, the center line of the axial section of the disk at the interface of the disc with the hub is shifted relative to the middle of the hub by the amount of "b", from 10.0 to 24.5 mm, while the outer surface of the disk is formed on the side of the rim and on the side of the hub by edge outer radius curves R1 and R2 directed towards the inner surface of the wheel, in the central part of the disk is formed by two sections of the central outer radial curves R3 and R4 directed towards the outer surface of the wheel and conjugated to each other, and is also formed by intermediate outer radius curves R5 and R6 directed towards the inner surface of the wheel and mated with the corresponding boundary and central outer radius curves, the inner surface of the disk is formed from the rim side and from the hub side, the inner radius curves R7 and R8 directed towards the outer surface of the wheel are formed by two chastkami central internal radius curves R9 and R10, directed toward the outer surface of the wheel and conjugate with each other, and is formed intermediate the outer radiused curves R11 and R12, are directed towards the inner surface of the wheel and mating with the respective internal edge and central radiused curves. 2. The railway wheel according to claim 1, characterized in that the outer edge radius curves R1 and R2 are made in the range of radii from 12 mm to 70 mm; boundary inner radius curves R7 and R8, made in the range of radii from 20 mm to 45 mm, the central outer and inner radius curves R3, R9, located on the side of the rim, made in the range of radii from 30 mm to 125 mm, the central outer and inner radius curves R4, R10 located on the hub side are made in the range of radii from 30 mm to 170 mm, intermediate outer radius curves R5, R11 are made in the range of radii from 30 mm to 230 mm and intermediate inner radius curves R6, R12 are made in the range of radii from 30 mm d 135 mm. 3. The railway wheel according to claim 1, characterized in that the angle of inclination of the disk to the axis of the wheel is from 76.5 ° to 82.5 °.

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