DESC:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
A METHOD FOR REDUCING BOGIE FRAME DISTORTION

Applicant:
BEML Limited
A company Incorporated in India under the Companies Act, 1956
Having address:
BEML Soudha, 23/1, 4th Main,
Sampangirama Nagar, Bengaluru,
Karnataka - 560 027, India

The following specification particularly describes the invention and the manner in which it is to be performed

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
[001] The present application claims priority from an Indian Provisional Application 201941053490 filed on 23rd December 2019.
TECHNICAL FIELD
[002] The present subject matter described herein, in general, relates to a method of reducing a bogie frame distortion and more specifically relates to optimization of process parameters for reducing the bogie frame distortion.
BACKGROUND
[003] A bogie is a module integrated with car body that supports & drives a metro car. Basically, the bogie supports and carry rail vehicle body, provides stability on both linear and curved track, stabilizes an impact of centrifugal forces when the rail vehicle runs on curves at high speed and improves riding comfort by absorbing vibration. A bogie frame is a main supporting part of the bogie for performing aforesaid functions as the bogie frame undergoes both static and dynamic loading in all directions. Hence, the bogie frame manufacturing becomes a critical task.
[004] A bogie frame mainly consists of two side frames and a transom wherein the transom is connected to the side frames. A bogie frame manufacturing comprises a multiple stage machining wherein the major machining is done on a vertical milling machine. Other jigs and fixtures required for bogie frame manufacturing includes single axis manipulator for side frame welding, two axis manipulator for transom welding, check & straightening machine, frame welding spinner jig, bracket integration jig and bogie integration jig. Further, an existing technology for manufacturing of conventional Indian Railway Bogie Frame uses MAG welding. In conventional Indian Railway Bogie Frame manufacturing, length of welding is less and hence, there is no distortion in the bogie frame. Whereas, in metro bogie frame, headstock and longitudinal channels are not available as per design. Because of which, the length of radiography welding increases and as a result, distortion occurred in the bogie frame due to excessive welding. Also, due to extensive welding, there is less stock available for other machining operations. In prior art figures, a larger distortion is observed due to excessive welding, a bevel angle of 45 degrees in a transom is observed, 6 mm root gap between the transom and the side frame is observed and conventionally, one end to other end welding is used for welding of the bogie frame. All the above-mentioned parameters may be responsible for the larger distortion of the bogie frame.
[005] Hence, there is a need of a method to reduce a bogie frame distortion and to provide stock availability for critical machining requirement.
OBJECT OF THE INVENTION

[006] It is an object of the present invention to reduce a distortion of a bogie frame.
[007] It is an object of the present invention to maintain machining stock availability for machining of bracketry items.
[008] It is an object of the present invention to ascertain fabrication dimensions before machining of a bogie frame.
[009] It is an object of the present invention to ensure radiographic quality of weld.
[0010] It is an object of the present invention to provide welding according to welding procedure specification (WPS).
[0011] It is an object of the present invention to optimize process parameters including a bevel angle of transom web plate and a root gap between transom to side frames.
[0012] It is an object of the present invention to provide optimized welding sequence.
SUMMARY
[0013] Before the present system and method are described, it is to be understood that this application is not limited to the particular machine or an apparatus, and methodologies described, as there can be multiple possible embodiments that are not expressly illustrated in the present disclosures. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only, and is not intended to limit the scope of the present application. This summary is provided to introduce aspects related to an apparatus for spot facing of a surface, and the aspects are further elaborated below in the detailed description. This summary is not intended to identify essential features of the proposed subject matter nor is it intended for use in determining or limiting the scope of the proposed subject matter.
[0014] The present subject matter relates to a method for reduction in distortion of a bogie frame. The said method comprises steps of : checking side frames and a transom for damages, fitting and aligning the side frames to the transom in an integration jig, ensuring a root gap of 3 mm between the side frames and the transom, ensuring a bevel angle of 30 degrees in a transom web plate, tack welding of the transom to the two side frames to secure predetermined position of the bogie frame, welding of right and left ends of the transom to the side frames simultaneously, welding of the transom to the side frames from center to one end diagonally, checking welding joints by radiography testing, mounting the bogie frame in a spinner jig, welding of plurality of bracketry items of the bogie frame, relieving stresses induced due to heavy welding, subjecting the bogie frame to grit blasting and primer painting and machining of unfinished parts of the bogie frame for finishing of the said parts. The said method is configured to provide a radiography quality of weld. Further, the above-mentioned welding method is configured to ascertain fabrication dimensions before machining. And, the explained welding method maintains machining stock availability for machining of bracketry items. Furthermore, the welding method as explained is configured to manufacture the bogie frame by steel and more specifically by a high corrosion resistance steel “SMA 490 BW”.

BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The foregoing summary, as well as the following detailed description of embodiments, is better understood when read in conjunction with the appended drawing. For the purpose of illustrating the disclosure, there is shown in the present document example constructions of the disclosure, however, the disclosure is not limited to the specific methods and apparatus disclosed in the document and the drawing:
[0016] The detailed description is described with reference to the accompanying figure. In the figure, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawing to refer like features and components.
[0017] Figure 1 (Prior Art) illustrates a larger distortion due to excessive welding.
[0018] Figure 2 (Prior Art) illustrates a bevel angle of 45 degrees in a transom.
[0019] Figure 3 (Prior Art) illustrates 6 mm root gap between a transom and a side frame.
[0020] Figure 4 (Prior Art) illustrates welding of a bogie frame from one end to other end used conventionally.
[0021] Figure 5(a) illustrates a top view of a bogie frame, in accordance with an embodiment of the present subject matter.
[0022] Figure 5(b) illustrates an isometric view of a bogie frame, in accordance with an embodiment of the present subject matter.
[0023] Figure 6 illustrates a stress analysis of a bogie frame, in accordance with an embodiment of the present subject matter.
[0024] Figure 7 illustrates a distortion in a bogie frame, in accordance with an embodiment of the present subject matter.
[0025] Figure 8 illustrates a bevel angle of a transom web plate of a bogie frame, in accordance with an embodiment of the present subject matter.
[0026] Figure 9 illustrates a root gap between a transom and a side frame of a bogie frame, in accordance with an embodiment of the present subject matter.
[0027] Figure 10 illustrates a welding sequence of a bogie frame, in accordance with an embodiment of the present subject matter.
[0028] Figure 11 illustrates an algorithm to perform a method to assemble a bogie frame with reduced distortion, in accordance with an embodiment of the present subject matter.
[0029] The figure depicts various embodiments of the present disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
[0030] Some embodiments of this disclosure, illustrating all its features, will now be discussed in detail. The words "comprising", “having”, and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. Although any systems and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary, systems and methods are now described. The disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms.
[0031] Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art will readily recognize that the present disclosure is not intended to be limited to the embodiments illustrated, but is to be accorded the widest scope consistent with the principles and features described herein.
[0032] A method for manufacturing a bogie frame is described wherein the reduction in distortion of the bogie frame is achieved. In an embodiment, the said bogie frame may configured to be a metro bogie frame. Further, plurality of process parameters comprising root gap between a side frame and a transom, bevel angle of a transom web plate and a weld sequence of a transom may be optimized. Also, a machining stock may be maintained for performing critical machining operations.
[0033] Referring to figure 5(a) and 5(b), a bogie frame (500) comprises two side frames (502) and a transom (504) wherein the transom (504) may configured to be connected to the two side frames (502). A surface (506) represents a connection between the two side frames (502) and the transom (504). The bogie frame (500) may be subjected to static and dynamic loading as the bogie frame (500) may be a main part to support a bogie.
[0034] Referring to figure 6, a stress analysis of the bogie frame (500) is shown. As can be seen from figure 6, a maximum distortion occurs near to a joint between the two side frames (502) and the transom (504).
[0035] Referring to figure 7, a distorted area (702) of the bogie frame (500) is shown. A reduction in distortion may be achieved by optimizing process parameters including root gap between a side frame and a transom, bevel angle of a transom web plate and a weld sequence of a transom.
[0036] Referring to figure 8, a bevel angle (802) of a transom web plate is shown. In the present subject matter, the aforesaid bevel angle (802) may be optimized to reduce the distortion of the bogie frame (500). In an embodiment, the bevel angle may configured to be of 30 degrees.
[0037] Referring to figure 9, a root gap between the transom (504) and the side frame (502) is shown. The aforesaid root gap may be optimized to reduce the distortion of the bogie frame (500). In an embodiment, the root gap may configured to be of 3 mm.
[0038] Referring to figure 10, a welding sequence adopted in the present subject matter is shown. Figure 10 (a) represents a welding from center to one end diagonally and figure 10 (b) shows simultaneous welding at both the ends. The said welding technique may helps in minimizing the bogie frame distortion.
[0039] Further, the method to optimize the above-mentioned process parameters to reduce the distortion of the bogie frame is described in figure 11. The two side frames (502) and the transom (504) may be individually checked for damages. Fitment and alignment of the two side frames (502) to the transom (504) may be ensured in an integration jig. In an embodiment, the root gap of 3mm between the side frame (502) and the transom (504) may be ensured and the bevel angle of 30 degree may be ensured for the transom web plate. After inspection, a full top and bottom of the bogie frame (500) may be subjected to a full welding. In an embodiment, the welding sequence as described may be ensured for minimizing the bogie frame distortion. In an embodiment, TAG welding may be used for the full welding of the bogie frame (500). Further, the fitment and alignment may be inspected to proceed further for welding. After the said welding, all welding joints may be subjected to a radiography testing. Then, the radiography testing may be inspected. Further, for welding of small bracketry items, the assembly (500) may be mounted on a spinner jig and the bracketry items may be welded. Then, the welded joints may be inspected. Further, stress relieving is ensured as stresses may be induced due to heavy welding. After stress relieving, the bogie frame (500) may be subjected to a grit blasting and a primer painting. At the end, for finishing of the bogie frame (500), some parts may be machined. Furthermore, the welding method as explained is configured to manufacture the bogie frame by steel and more specifically by a high corrosion resistance steel “SMA 490 BW”.
[0040] Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include the following.
[0041] Some of the embodiments of the method uses MIG welding and TAG welding for obtaining a weld of radiography quality.
[0042] Some of the embodiments of the method enables welding of casting to a metal plate.
[0043] Some of the embodiments of the method enables preheating of casting before welding of joints.
[0044] Some of the embodiments of the method enables machining of bogie frame using 5 axis vertical milling machine.
[0045] Some of the embodiments of the proposed bogie frame provides better suspension and reliability.
[0046] Although implementations for the said method have been described in language specific to structural features, it is to be understood that the appended specifications are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as examples of implementation for the apparatus 500.
,CLAIMS:
1. A method for reducing a bogie frame distortion comprising the steps of:
checking two side frames (502) and a transom (504) for damages;
fitting and aligning the side frames (502) to the transom (504) in an integration jig;
ensuring a root gap of 3 mm between the side frames (502) and the transom (504);
ensuring a bevel angle of 30 degrees in a transom web plate;
tack welding of the transom (504) to the two side frames (502) to secure predetermined position of the bogie frame (500);
welding of right and left ends of the transom (504) to the side frames (502) simultaneously;
welding of the transom (504) to the side frames (502) from center to one end diagonally;
checking welding joints by radiography testing;
mounting the bogie frame (500) in a spinner jig;
welding of plurality of bracketry items of the bogie frame (500);
relieving stresses induced due to heavy welding;
grit blasting of the bogie frame (500) followed by primer painting; and
machining of unfinished parts of the bogie frame (500) for finishing of the said parts.
2. The method as claimed in claim 1, wherein the welding process is configured to provide a radiography quality of weld.
3. The method as claimed in claim 1, wherein the welding process is configured to evaluate fabrication dimensions before machining.
4. The method as claimed in claim 1, wherein the welding process is configured to maintain machining stock availability for machining of bracketry items.
5. The method as claimed in claim 1, wherein the welding method is configured to optimize process parameters like the root gap between the side frame (502) and the transom (504), bevel angle of the transom web plate and predetermined welding sequence.
6. The method as claimed in claim 1, wherein the welding method is configured to manufacture the bogie frame (500) by a steel.
7. The method as claimed in claim 1, wherein the welding method is configured to manufacture the bogie frame (500) by a high corrosion resistance steel “SMA 490 BW”.
8. The method as claimed in claim 1, wherein the bogie frame (500) manufactured by the said method is configured to be RS13 DMRC Bogie frame.