RU2487031C2 - Freight car bogie solebar - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: car bogie solebar comprises top and bottom girths 1, 2 interconnected by vertical struts 3 to form spring opening 21, inclined girths 4, mid elements 5 connected with horizontal bearings sections making axle box openings 6. Inner cross-section of top girth is shaped to semi-ellipse with ellipticity of 0.864-1 and bulged wall at transition of horizontal bearing sections to mid elements of inclined girths. Metal in said bulged sections contains 0.8-1.2% of chromium, 2-4% of nickel, 0.2-0.4% of molybdenum, up to 0.5% of vanadium, content of other metal varies with the limits of bogie solebar main metal. Radius at transition of horizontal bearing sections to mid elements of inclined girths makes 56-65 mm while wall thickness gradually decreases toward inclined girths. Note also that wall thickness at transition of mid elements to bearing horizontal girths gradually decreases toward horizontal girths.

EFFECT: higher strength of solebar.

2 cl, 4 dwg

Description

The invention relates to railway rolling stock, namely to the construction of a molded side frame of a freight car truck.

Known design of the side frame of the railway cart, indicated in patent RU No. 2323243 (IPC B61F 5/52, filed July 10, 2006).

SUMMARY OF THE INVENTION A side frame design is proposed in which the lower corner of the spring aperture of the side frame is made in the form of a stepwise transition of the vertical column of the frame to the lower horizontal belt, along with this, the upper transition surface is a continuation of the bridge, poured into the flange of the technological holes of the frame and goes into the limiters of the Wedge spring, the outer the surface of which repeats the configuration of the transition of the side wall of the lower belt to the side wall of the inclined belt. The transition of the side wall of the lower belt to the side wall of the inclined belt is made using conjugated radii, and one of the mating radii of the transition has a center that coincides with the center of the canister of the spring. In addition, along the contour of the joint of the inner jaw guide with an inclined belt, a U-forming hole is made in the inclined belt. The refraction of the upper horizontal belt and the vertical side surfaces of the frame in the over-box zone coincides with the transverse reference plane of the reference tide of the inner jaw guide. Supporting tides are made on the vertical side walls of the frame in the over-box zone, the outer surfaces of which are located at an angle to the horizontal supporting surface of the axle box opening.

The proposed design of the side frame reduces the likelihood of microcracks.

However, these measures are not enough to prevent the occurrence of microcracks in the side frames in harsh operating conditions, especially when the carts enter the curves. In this case, the side frame works for torsion.

Also known is the design of the side frame of the trolley of a freight car (patent RU No. 2294855, (IPC B61F 5/52, claimed September 28, 2005).

In the claimed invention, the task of increasing reliability and increasing the safety factor of fatigue resistance is solved due to the combination of the following essential features of the invention. The side frame contains an upper closed-section belt with consoles forming axle openings, a closed closed lower belt with a supporting platform for a spring kit, two closed-section inclined belts with technological windows connecting the upper and lower belts, and a central spring opening limited by a supporting platform for a spring a set of the lower belt, the upper belt and the inclined belts, and in the zone of connection of the lower belt with each inclined belt three converging ribs are made, one of which is located the lower part of the inclined belt from the periphery to the center, the other along the curved part of the spring opening in the zone of articulation of the lower belt with the inclined belt, the third is made as a continuation of the supporting platform for the spring set, and protrusions are formed symmetrically with respect to the central transverse plane of the frame in the convergence zones of the above-mentioned ribs creating conditions for directional crystallization, and the protrusions combine these ribs and smoothly mate with their side surfaces, in addition, the protrusions are made We are not protruding into the central spring opening.

The authors have done a lot of work to improve the strength and performance characteristics of the side frames of a freight wagon trolley. Using the directed crystallization method, the safety factor of fatigue resistance was increased, as well as the rigidity of the side frame of the trolley by introducing additional ribs and thickening the walls.

The operation of these frames showed that the rigidity of the side frames is insufficient.

The closest analogue of the invention is the side frame of the truck wagon, presented in the patent for a utility model. RU No. 95619 (IPC B61F 5/00, declared on 02/08/2010).

The essence of the invention is that the shape of the individual elements of the side frame is changed, the shape is described further through the aspect ratio. The side frame contains an upper belt of a closed box section with consoles forming axle openings, a lower belt of a closed section with a support platform for a spring kit, two inclined belts of a closed section with technological windows connecting the upper and lower belts and a central spring opening limited by a support platform for a spring a set of the lower belt, the upper belt and inclined belts, while the height of the closed box section of the upper belt of the overbook opening and its width are in shenii 1.15 ... 1.25.

In addition, part of the inner corner of the axle box opening is formed by a section of the inclined belt. The radius of the technological window of the inclined belt is such that a ratio of the distance from the edge of the technological window to the edge of the inclined belt to the width of the inclined belt is within 0.5-0.6.

A study of the manufactured frames of this design for fatigue strength showed a relatively low number of cycles before the appearance of cracks.

The objective of the proposed design of the molded side frame of the trolley is to further reduce the stress concentration in critical places of the frame and, above all, in the places of transition of horizontal supporting sections to inclined belts.

The goal is achieved by the fact that the side frame of the freight wagon trolley, comprising a closed upper section belt with consoles forming axle openings, a closed section lower section with a support platform for a spring set, two closed section inclined sections with technological windows connecting the upper and lower sections and the central one spring opening, limited by the support platform for the spring set of the lower belt, the upper belt. The difference is that the internal section of the upper zone at the transition points of the horizontal supporting sections to the middle elements of the inclined zones is made in the lower part of the box section into a semi-ellipse with an ellipticity in the range from 0.864 to 1.0 and a thickened wall.

Metal in a thickened place contains chromium from 0.8 ... 1.2%, nickel 2 ... 4%, molybdenum 0.2 ... 0.4%, vanadium up to 0.5%, the rest of the elements are contained within the base metal of the side frame of the cart.

The radius at the transition points of the horizontal supporting sections to the middle elements of the inclined belts is 56 ... 65 mm, and the wall thickness in the section gradually decreases in the direction of the middle elements of the inclined belts and becomes box-shaped at the place of the U-shaped jumpers, symmetrically the wall thickness in the section at the transition points of the middle elements in inclined belts in the horizontal supporting zones decreases in the direction of horizontal sections and gradually becomes box-shaped.

The essence of the invention is illustrated by drawings, which depict:

Figure 1 - General view of the side frame of the trolley (side view);

Figure 2 is a fragment of the side frame with the changes (side view);

Figure 3 - section aa the design of the proposed side frame;

Figure 4 is a section along aa of the analogue of the side frame (patent RU No. 95619).

The side frame of the carriage trolley consists of an upper belt 1 and a lower 2 horizontal belts interconnected by vertical columns 3, forming together with the horizontal belts 1 and 2 a spring aperture 21, the upper belt 2 of the frame goes into its inclined belts 4, the middle elements 5, which mated with horizontal supporting sections 10, form box openings 6.

Each axle box 6 consists of an inner 7 and an outer 8 jaw guides with supporting tides and an over-axle zone 9.

The inner jaw guide 7 is associated with the middle element 5 of the inclined belt 4, having in its cross section a trough-like shape.

On the contour of the joint of the inner jaw guide 7 with an inclined belt 4, a U-shaped jumper 11 is made, forming a hole in the middle element 5 of the inclined belt 4.

The lower belt 2 and the upper belt 1, as well as the over-slip zones 9, have a box-shaped cross-section at the points of transition of the horizontal supporting sections 10 to the middle elements 5 of the inclined belt 4. The box-shaped form goes into a semi-ellipse at the bottom with an ellipticity in the range of 0.864 ... 1.0 and with a thickened wall, the thickness of the side walls increases accordingly. The maximum thickness of the wall and base of the semi-ellipse gradually decreases upward, and at the ends of the radius of the major axis, the thickness is equal to the thickness of the box section.

The side wall 12 of the upper belt 1, the side walls 13 of the lower belt 2, as well as the side walls 14 of the inclined belts 4 are parallel to the longitudinal plane of the frame.

Figure 2 presents a fragment of the side frame of the trolley. The shaded part of the side frame from the transition of the horizontal sections 10 to the middle elements of the inclined belts 4, section A-A, has a semi-ellipse with an ellipticity in the range of 0.864 ... 1.0 and a thickened wall in the lower part of the box section.

Figure 3 presents a section aa of figure 2. It is known that the ratio of the lengths of the minor and major semi-axes is usually called the compression coefficient of the ellipse or ellipticity

$$K=\frac{r}{R}$$

where R is the semimajor axis, r is the semimajor axis.

Figure 4 presents a section aa analogue of the side frame.

From a comparison of the cross sections of the prototype and the proposed design of the side frame, a thickening of the wall is clearly visible.

The proposed design of the side frame works as follows.

During operation, the side frames perceive static and dynamic vertical loads (weight of the car and load, impacts when the car passes along the nerves of the track), longitudinal loads (traction with uniform movement of the train, force when the cars collide), and also experience the effect of torque when entering wagons in curves. Moreover, the bulk of the dynamic vertical loads is cyclical in nature and the fatigue strength of the side frames (the ability to withstand the effects of cyclic loads for a long time) is the main characteristic of their operational reliability.

The main cause of side frame failures in operation is the formation and development of fatigue cracks at the locations of stress concentrators. The greatest voltage is at the transition points of the horizontal supporting sections in the middle elements of the inclined belts (see figure 2).

A feature of the fatigue process is its locality - as a result of the accumulation of damage in the overstressed zone with continued cyclic loading, failure occurs (L.N. Stepanov, S.A. Grassman, S.I. Kabanov, A.L. Bobrov, S.A. Becher ., A. A. Bolganov. “Acoustic emission monitoring of box-shaped side frames,” J. Defectoscopy No. 3, 2011. pp. 10-17).

Therefore, in these places it is required to reduce the voltage.

It was proposed to reduce the voltage by thickening the wall in places from the transition of the horizontal supporting sections 10 to the middle elements of the inclined belts 4. Section A-A (Fig. 2) shows a thickening which is achieved by a semi-ellipse in the lower part of the box section.

The radius at the transition points of the horizontal supporting sections to the middle elements 5 of the inclined zones 4 is increased and makes 56 ... 65 mm, the wall thickness gradually decreases in the direction of the middle elements of the inclined zones 4 and at the place of the U-shaped jumpers becomes equal to the thickness in the box section, symmetrically wall thickness at the points of transition of inclined belts to horizontal support belts decreases in the direction of horizontal sections and gradually passes into a box-shaped section.

Therefore, in a section along AA of the side frame, a semi-ellipse with a thickened wall is formed in the lower part of the box section. Ellipticity is 0.864.

$$K=\frac{60.5}{70}=0.864$$

where R = 70 mm, r = 60.5 mm.

The interval of effective stress relief in the hazardous areas of the side frame is in the range of 0.864 ... 1.0.

In the manufacture of the side frame, the proposed section AA of FIG. 3 allows the passage of hot metal in the flask easier compared to the prototype of FIG. 4. Thus, cooling, followed by crystallization, will take place uniformly throughout the casting, and there will be no cracks due to temperature differences.

Another distinctive feature is the use of metal with increased strength characteristics in the thickened wall of section AA (Fig. 2) of the internal section of the upper belt from the transition point of the horizontal supporting sections to the middle elements of the inclined zones 4 in the lower part to the U-shaped bridges.

The metal contains chromium 0.8 ... 1.2%, nickel 2 ... 4%, molybdenum 0.2 ... 0.4%, vanadium up to 0.5%. The remaining elements within the base metal of the side frame.

The metal should possess not only a high tensile strength, and a high yield strength while maintaining high viscosity, which is characterized by a large impact resistance.

The dissolution of alloying elements in Feα occurs as a result of the replacement of iron atoms by the atoms of these elements.

Atoms of alloying elements, differing from iron atoms in size and structure, create stresses in the lattice that cause a change in its period (A.P. Gulyaev. "Metallurgy." Publishing House "Metallurgy" 1978, pp. 349-350).

In the same figure, Fig. 280 shows the influence of alloying elements on the properties of ferrite (hardness and toughness) and Fig. 281 shows the effect of alloying elements on the cold resistance threshold.

It is the influence of the chromium and nickel additives that provide an increase in mechanical properties and cold resistance. To obtain the necessary strength of the metal of the side frame, it is proposed to add nickel from 2 ... 4% and chromium to 0.8 ... 1.2%.

To ensure the thermal stability of steel, i.e. increase the yield strength, molybdenum 0.2 ... 0.5% is introduced.

Molybdenum, dissolving in the phases of iron, grinds the grain, which is very beneficial for the mechanical properties of the metal, increases strength and resistance to impact.

For dispersion hardening and grinding of grain, vanadium is introduced.

The most effective effect of vanadium on the properties of steel is achieved with a vanadium content of 0.5% in steel. In this case, the hardening phase enters the solution in an amount sufficient for subsequent dispersion hardening, and its quantity remains insoluble, which is necessary to inhibit grain growth during heating.

Moreover, the steel must be well deoxidized, have a sufficient temperature to create a favorable shape and location of the resulting microinclusions.

The proposed design of the side frame of the freight car truck was manufactured and tested for cyclicity.

The test results are positive.

Claims (2)

1. The side frame of the freight car truck, comprising an upper closed-section belt with consoles forming axle openings, a closed closed lower belt with a support platform for a spring set, two closed-section inclined belts with technological windows connecting the upper and lower zones and the central spring opening, limited by the support platform for the spring set of the lower belt, the upper belt, characterized in that the inner section of the upper belt at the transition points of the horizontal supporting sections in the middle elements of inclined belts are made in the lower part of the box section into a semi-ellipse with an ellipticity in the range from 0.864 to 1 and with a thickened wall, metal in the thickened parts contains chromium up to 0.8 ... 1.2%, nickel 2 ... 4%, molybdenum 0.2 ... 0.4%, vanadium up to 0.5%, other elements within the base metal of the side frame of the trolley. 2. The side frame of the freight car truck according to claim 1, characterized in that the radius at the points of transition of the horizontal supporting sections to the middle elements of the inclined belts is 56 ... 65 mm and the wall thickness gradually decreases in the direction of the inclined belts and in the place of the U-shaped jumpers passes into the box, symmetrically, the wall thickness at the points of transition of the middle elements of the inclined belts to the horizontal support belts decreases in the direction of the horizontal sections, passing gradually into the box.

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