RU2294855C1 - Side frame of freight car bogie - Google Patents

Abstract

FIELD: railway transport; freight cars.

SUBSTANCE: freight car bogie side frame has upper belt 1, lower belt 4, two inclined belts 6, 7 connecting upper and lower belts. Ribs are made in zone of connection of lower belt with each inclined belt. Rib 12 is arranged in lower part of inclined belt from periphery to center, and rib 13, along curvilinear part of spring aperture in zone of coupled of lower belt with inclined belt. Rib 14 is made as extension of support platform 5 for spring set. Projections 15 are formed symmetrically relative to central plane of frame in zones of rib meeting which create conditions for orientated crystallization, uniting ribs and mating with their side surfaces. Projections do not extend into central spring aperture. Construction strength of frame is improved owing to elimination of shrinkage porosities and cavities in places of location of stress concentrators.

EFFECT: improved reliability of construction and increased fating resistance safety factor.

4 dwg, 2 tbl

Description

FIELD OF THE INVENTION

The invention relates to railway rolling stock, in particular to the construction of a cast side frame of a freight car truck.

State of the art

There are various designs of the side frames of the trucks of a freight car (US 5305694, US 5481986, US 5718177, US 6125767, US 6543367, RU 2116921).

A side frame of a wagon trolley is known, including an upper and lower belt connected by vertical columns forming a spring opening, two inclined belts connecting the lower belt with end parts covering axle openings and having horizontal supporting surfaces conjugated with vertical parts. The angles of mating of the walls in the spring and axle openings are located in the hardening zones, the compressive stress of which does not exceed 30 MPa, with local residual deformations not higher than the deformation corresponding to the elastic limit of steel (RU No. 41687, U1, B61F 5/52, 2004).

Also known is the side frame of a freight wagon trolley containing axle openings at the ends, a lower belt, an upper belt, inclined belts, a middle opening, guides, a T-shaped transverse bracket rigidly mounted on the lower belt, and also attachment points for a longitudinal leash, vertically arranged dampers oscillations and suspension triangles, the middle opening of the frame is formed by the lower belt, upper belt and inclined belts of closed section, the mating sections of the inclined belts with the upper belt are made along a radius R ₁ equal to 150-160 mm, and with the lower one - along a radius R ₂ equal to 220-230 mm, while the guides are placed on cantilever-mounted stops, each of which covers an inclined belt on three sides (RU No. 37683, U1, B61F 5/52, 2004) .

The closest analogue of the invention is a side frame 100.00.002-4 of a freight car truck, which is a molded shaped structure formed by a lower belt, upper belt and two inclined belts, with axle box and central spring aperture. Belts have a box section. Technological windows are located along the inclined belt in the transition zone from the axle box to the central spring opening. To strengthen the structure in areas where there are stress concentrators, the frame is supported by stiffeners located symmetrically relative to the central plane of the frame. Stiffening ribs are located along the width of the inclined belt, other ribs - along the edging of the central spring opening in the place of the curvilinear transition from the lower belt to the inclined belt. The ribs converge with each other and with the corresponding ribs located on the lower edge of the central spring opening and made as a continuation of a flat platform under the spring set. In addition, to harden the most loaded section of the axle box opening, a pair of inclined straight ribs symmetrically located relative to the central plane of the frame are made on the frame. These ribs reinforce the radius transition zone from the inclined belt to the upper belt. Technological windows in inclined belts have a complex shape (www.promlit.com, publ. 08.04.2005).

According to the results of complete fatigue tests of the closest analogue, the fatigue safety margin of the studied side frames, based on the axial load of 23.5 tf and speed of 120 km / h, corresponds to n = 1.56 (see table 1), which exceeds the safety factor, established in the normative and technical documentation (n = 1,4).

The disadvantages of the above analogues, including the closest analogue (see table 1), are the insufficient fatigue strength of the frame in the areas where stress concentrators are located, especially in the spring opening in the lower part of the frame at the interface between the inclined belts and the lower belt, in the technological zone windows and the inner radius of the axle box.

Disclosure of invention

The objective of the invention is to increase the reliability of the design of the frames, increase the safety factor of fatigue by increasing the strength properties of the frame.

Special requirements are imposed on railway casting for quality, since the safety of train traffic depends on this. Cast side frames have a complex structure with hollow upper, lower and inclined belts. As a result of this, it is practically impossible to obtain a casting without defects. The most common defect causing the destruction of molded side frames is loosening and shrinkage shells, which are formed, including at the locations of stress concentrators. To compensate for possible defects in the most dangerous areas on known structures, ribs are made or local thickenings of the walls of the structure are formed. In the closest analogue, in the places of radial conjugation of the lower frame belt with the inclined belt, ribs are arranged symmetrically with respect to the central transverse plane of the frame.

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 joint zone of the lower belt with the inclined belt, the third is made as a continuation of the supporting platform for the spring set, while symmetrically relative to the central transverse plane of the frame in the convergence zones of the above-mentioned ribs are formed protrusions creating conditions for directional crystallization, moreover, the protrusions combine the said ribs and smoothly mate with their side surfaces, in addition, the protrusions are made We are not protruding into the central spring opening.

The technical result from the use of the invention is to improve the structural strength of the frame by eliminating loosening and shrinkage shells in the locations of stress concentrators, increasing the reliability of the structure, increasing the safety factor of fatigue resistance to 2.06. Note: the safety factor of fatigue resistance is calculated for cast parts in accordance with the “Rules for the calculation and design of railroad cars of the Ministry of Railways 1520 mm gauge (non-self-propelled)” according to the “Methodology for fatigue testing of cast parts of biaxial bogies of freight cars”.

The achievement of the specified technical result is due to the application of certain approaches to the design and manufacturing technology of the side frame, which together provide the output of quality products.

When developing the claimed invention, it was experimentally established that in the most loaded place — in the area of transition from the lower zone to the inclined zones — thermal units are formed in the prototype that concentrate shrinkage porosity and other casting defects. Thickening of the walls of the belts or an increase in the thickness of the ribs did not actually improve the structural strength, but at the same time increase the mass in the region of thermal units. Therefore, to solve the problem of improving the strength and operational characteristics of the product, changes were made to the design of the side frame, which allowed, in addition to purely structural advantages, the use of new technological methods for producing cast billets, inextricably linked to changes in the frame design. The manufacturing technology of the frame casting was based on the directional crystallization method, which consists in the establishment of certain casting and cooling conditions for castings. The use of this technology is associated with the well-known fact that directional crystallization eliminates shrinkage porosity, cracks and gives products increased strength.

To achieve the above technical result, a protrusion was made in the lower part of the frame, combining the three reinforcing ribs converging in this place, which were in the prototype structure (as described above). The introduction of the protrusion into the frame design made it possible, on the one hand, to additionally reinforce the critical section of the frame, and on the other hand, to create conditions for directional crystallization in this place.

Studies have shown that the implementation of the protrusion at the point of convergence of the ribs, as well as additional reinforcement of the spring aperture with ribs located in the central spring aperture along the radial conjugation of the upper belt with inclined belts, reduced the risk of destruction of the frame at the most loaded place, the lower corner of the spring opening.

The achievement of the specified technical result is confirmed by fatigue tests of the side frames (test results - see table 2), conducted by VNIIZhT.

Analysis of the invention for compliance with the patentability condition “inventive step” showed that devices are known from the prior art that describe various modernizations of one of the most vulnerable points of the side frame — the articulation of the lower belt with an inclined belt.

Thus, a side frame construction is known in which the thickness of said belts is increased at the interface between the inclined belt and the lower belt, in addition, this place is supported by internal ribs located in the internal cavity of the frame (US No. 5718177, B64F 5/00, 1998). . This solution allows to some extent to strengthen the zone of articulation of the inclined and lower belts, but does not solve the problem of eliminating defects that occur during the manufacturing of cast frames.

A device is also known (US patent US No. 6543367, B61F 3/00, 2003), in which the inclined belt is made in the form of a flat wall, reinforced around the perimeter with ribs, while the lower belt is made with a rib that prevents deformation when the frame is fully loaded . Technological windows in a flat wall are reinforced with ribs located diagonally on the window and dividing it into two separate openings. These ribs are made in order to compensate for the insufficient strength of the flat wall and reduce the risk of destruction of the frame on the specified technological windows.

Distinctive features of the claimed technical solution have not been identified from the prior art, and in the known devices described above, the task of increasing the reliability of the side frame structure has been solved by other means (introducing additional ribs, making thickened walls). Moreover, from the above and other sources of information known to the applicant, the side frame designs are not known, which, when tested, showed a fatigue safety factor of more than 2.0, as claimed by the invention.

Brief Description of the Drawings

The invention is illustrated by drawings, which depict:

figure 1 - side frame, the main view;

figure 2 - place a from figure 1;

figure 3 is a side frame, side view;

figure 4 is a place a from figure 1, side view.

The implementation of the invention

The side frame of the freight car truck consists of an upper belt 1 with consoles 2 forming box openings 3, a lower belt 4 of a closed section with a support platform 5 for a spring set. Two inclined belts 6 and 7 with technological windows 8 and 9 connect the upper 1 and lower belt 4. The central spring opening 10 is limited by the supporting platform 5 for the spring set of the lower belt 4, the upper belt 1 and the vertical belts 11 for installing the strips.

Three converging ribs 12, 13 and 14 are made at the junction of the lower belt 4 with each inclined belt 6 or 7. The rib 12 is located in the lower part of the inclined belt 6 and 7 from the periphery to the center, another rib 13 is formed on the edging in the curved part of the central spring the opening 10 at the junction of the lower belt 4 with the vertical belt 11. The third rib 14 is made as a continuation of the support platform 5 for the spring set.

Symmetrically with respect to the central transverse plane of the frame 14 in the areas of convergence of the above-mentioned ribs 12, 13, 14, protrusions 15 are formed, combining these ribs and mating with their side surfaces. The protrusions 15 are made not protruding into the Central spring opening 10 of the frame.

The side frame of the freight car truck is made of steel casting on an automatic molding line in sand and clay molds. The rods are made on rod machines with a triethylamine purge. The spring trolley kit (not shown) consists of springs, the number of which is selected depending on the capacity of the car. In the upper part of the axle box openings there are seats with which the side frames rest on the axle boxes, and on the sides - axle jaws. Five cylindrical protrusions are cast on an inclined belt 6 or 7, part of which is felled in accordance with the actual distance between the outer jaws of the axlebox openings. The selection of the side frames during assembly of the trolleys is carried out according to the number of cylindrical protrusions left to comply with the tolerances to ensure parallel axles of the wheelsets.

Table 1 Fatigue test results and fracture characteristics of side frames (closest equivalent) No. Load in kN (tf) Number of cycles Place of destruction Kink defects P _max P _min P _a Before the crack Before the break one 60 10 25 1670000 1939900 Spring opening Shrink shell 2 64 6 29th 1172000 1250000 Spring opening angle No obvious defects 3 58 12 23 2280000 2,400,000 Spring opening Shrink shell, infusion of the lower zone at the fracture

table 2 Fatigue test results and side frame failure characteristics
(claimed invention) No. Load in kN (tf) Number of cycles Place of destruction Kink defects P _max P _min P _a Before the crack Before the break one 60 10 25 3306000 On the corner of the axle box no 2 60 10 25 7714000 Not collapsed --- 3 60 10 25 3410000 On the corner of the spring opening no

Claims (1)

A side frame of a freight wagon trolley containing a closed upper section belt with consoles forming axle openings, a closed section lower belt with a support platform for a spring kit, two closed section inclined belts with technological windows connecting the upper and lower zones, and a central spring opening limited a supporting platform for the spring 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, ribs are made, one of which located in 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 support platform for the spring set, characterized in that it is symmetrical relative to the central plane of the frame in the convergence zones of the aforementioned protrusions creating conditions for directional crystallization are formed above the ribs, combining the said ribs and mating with their lateral surfaces, while the protrusions are not made high blunt in the central spring opening.

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