DESC:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patent Rules, 2003
COMPLETE SPECIFICATION
(See sections 10 & rule 13)
1. TITLE OF THE INVENTION
A FIXTURE FOR FATIGUE TESTING OF METRO BOGIE CHASSIS
2. APPLICANT (S)
NAME NATIONALITY ADDRESS
BEML LIMITED IN BEML Soudha, No 23/1, 4th Main S.R. Nagar, Bengaluru- 560027, Karnataka, India.
3. PREAMBLE TO THE DESCRIPTION
COMPLETE SPECIFICATION

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

FIELD OF INVENTION:
[001] The present invention relates to the field of testing device. The present invention in particular relates toa fatigue test fixture for fabricated metro bogie chassis.
DESCRIPTION OF THE RELATED ART:
[002] For testing, e.g. fatigue testing, of products, or parts for products, such as vehicle parts, it is desirable to introduce loads in a manner allowing test results to be mapped to individual load scenarios. It is also desirable to introduce loads in a manner which closely reflects loads provided during actual use of the product.
[003] Reference may be made to the following:
[004] Publication No. WO2017082787 provides a test rig comprising - a first support structure, and - a second support structure connected to the first support structure whereby the second support structure is movable in at least a first degree of freedom in relation to the first support structure, - characterized - in that the test rig comprises a connection device arranged to connect a first portion of a test piece to the first support structure, - in that the test rig comprises a second actuator arranged to provide a second load between a second portion of the test piece and the second support structure, and - in that the test rig comprises a first actuator arranged to provide a first load between the first support structure and the second support structure, the first load having the direction of the first degree of freedom.
[005] Publication No. CN114235448 discloses a railway vehicle bogie wheel fatigue damage assessment method and system. The method comprises the steps of obtaining a dynamic vertical load and dynamic transverse load time history curve of a railway vehicle bogie wheel; based on the vertical load-stress transfer function and the transverse load-stress transfer function, radial, circumferential and tangential stress time travel curves of a set key area of the wheel are obtained; further obtaining a stress time travel curve of the wheel in any set direction of the key area; counting the stress time travel curve in any set direction of the key area by using a rain flow counting method to obtain a stress spectrum; based on the stress spectrum, the equivalent stress of the wheel is calculated, and then the fatigue damage life of the wheel during operation of the railway vehicle is obtained through calculation. According to the invention, the fatigue damage distribution of the wheel fatigue key area in any direction can be realized, the stress direction corresponding to the maximum fatigue damage in the wheel service process can be obtained, and the patch direction can be conveniently determined in the subsequent wheel line tracking test.
[006] Publication No. CN110823535 discloses a bogie test stand, which belongs to the technical field of vehicle engineering. The bogie test stand comprises a base, a gantry, a vertical loading device, a transverse actuator, a first high-frequency vibration excitation device, a second high-frequency vibration excitation device and an acquisition system, wherein the first high-frequency vibration excitation device and the second high-frequency vibration excitation device are arranged on the base and arranged on the two sides of the gantry correspondingly; each of the first high-frequency vibration excitation device and the second high-frequency vibration excitation device comprises a driving motor, a first rolling wheel and a second rolling wheel which are arranged on the base; and the driving motors are connected with the first rolling wheels and the second rolling wheels. By changing the edge shapes of the first rolling wheels and the second rolling wheels, the wheel vibration frequency can be adjusted, so that a bogie can be in different high-frequency vibration working conditions, and the vibration fatigue tests can be carried out on core parts and accessories of the bogie.
[007] Publication No. CN113804465 provides a constraint device for a framework fatigue test and a framework fatigue test system, the device comprises a rigid primary suspension height simulation body and an elastic primary suspension elastic simulation body, and the primary suspension elastic simulation body is arranged at the bottom end of the primary suspension height simulation body; a simulation primary suspension assembly is mounted on the simulation axle box through the primary suspension elastic simulation body; the primary suspension elastic simulation body elastically deforms when subjected to external force so as to flexibly restrain the side beam of the to-be-tested framework and the simulation axle box, and a test force is transmitted to the simulation axle box through the side beam of the to-be-tested framework and the simulation primary suspension assembly. According to the device and the system, the real stress state of the primary suspension tool is restored, and the primary suspension tool is elastically deformed when subjected to external force, so that the side beam and the simulated axle box of the to-be-tested framework are flexibly restrained, the load transmission path of the real axle box is restored, and the accuracy of a fatigue test result of the bogie framework is ensured.
[008] Publication No. CN213779521 provides a fatigue test tool for a train bogie. The fatigue test tool comprises a base, a stand column and a support. The stand column is fixedly installed on the base, and the stand column is connected with the base in a welded mode. Reinforcing ribs are welded and installed at the joints of the stand columns and the base. The support is installed on the outer wall of the stand column in a welded mode, and the support is located on the inner side of the stand column. The support is fixedly installed on the base through bolts and located on one side of the stand column. The air cylinder is fixedly installed on the upper portion of the support through a bolt, and the end of the air cylinder is sleeved with the clamping plate. The framework is placed at the top ends of the stand columns. By improving the fatigue test tool of the train bogie, the fatigue test tool has the advantages of being reasonable in structural design, capable of restraining a framework in the vertical direction, the transverse direction and the longitudinal direction, high in restraining capacity, high in fixing firmness, high in stability and capable of guaranteeing that the experiment process is completed at a time, and therefore the problems and defects of the fatigue test tool are effectively solved.
[009] Publication No. CN213041519 relates to a fatigue test tool of a train bogie, aims to solve the problems that the train bogie is inconvenient to mount and dismount and different types of train bogies are inconvenient to test in the fatigue test process of the existing train bogie, and provides the following scheme: the fatigue test tool comprises a base, wherein two symmetrical stand columns are fixedly mounted at the top of the base, a fixing plate is fixedly mounted at the tops of the two stand columns, an air cylinder is fixedly mounted at the top of the fixing plate, an adjusting assembly is fixedly mounted at the top of the base, a mounting seat is fixedly mounted at the top of the adjusting assembly, and a bogie is placed at the top of the mounting seat; according to the fatigue test device for the train bogie, in the fatigue test process of the train bogie, the train bogie can be conveniently mounted and dismounted, the train bogies of different models can be conveniently tested, and the fatigue test device is simple in structure and convenient to use.
[010] Publication No. CN210719689 discloses a fatigue test tool for a train bogie. The utility model relates to the technical field of bogie frame fatigue tests, in particular to a bogie frame fatigue test device which comprises an adjusting assembly, a mounting plate and a train bogie, the mounting plate is arranged on the adjusting assembly, the train bogie is arranged on the mounting plate, and the adjusting assembly comprises an upper adjusting plate, a lower fixing plate, a first driving cylinder, a second driving cylinder and a third driving cylinder. The fatigue test tool for the train bogie is simple in structure, convenient to operate, high in practicability and convenient to install and maintain, the train bogie is placed on the installation plate, the angle of the train bogie is adjusted through the adjusting assembly, the working efficiency is greatly improved, the production cost is reduced, and the fatigue test tool is suitable for being widely applied and popularized.
[011] Patent No. US4748854 relates to a fatigue test apparatus in which a specimen to be tested is attached at its ends to a pair of opposing pistons positioned within a pair of opposing cylinders. The cylinders are attached to a support frame such that the specimen is oriented substantially vertically. In a preferred embodiment, the specimen is enclosed in a heat chamber to test at high temperatures. Each of the pistons is attached to a shaft having a weight at its end and the weights are drivingly connected to a pair of shakers which are actuated to vibrate 180 DEG out of phase with each other. The cylinders are pressurized to exert a static tensile load on the specimen, and the shakers are actuated to exert a dynamic tensile load which is superimposed on the static load and travels through the weights, shafts and pistons to the specimen.
[012] Publication No. CN201476969 relates to a bogie fatigue testing stand, which comprises a control system and a mechanical system; the control system is connected with the mechanical system by an actuator; the mechanical system comprises a workbench and two portal frames; each portal frame comprises upright columns and lateral beams; longitudinal beams are mounted between the lateral beams of the two portal frames. The utility model has a reasonable structure and convenient operation; adopts a double portal frames mechanism, connects two portal frames by two longitudinal beams. The testing stand can be used for performing three tests at the same time, increases test efficiency greatly; and increases the test loading tonnage for the same design weight. The testing stand of the utility model can apply transverse and longitudinal load conveniently; at the same time, two longitudinal beams are connected between the two portal frames; small transverse beams can be mounted on the longitudinal beams; in this way, the vertical load can be applied at any point in the platform scope.
[013] Publication No. CN101363773 relates to a fatigue strength test stand of a locomotive bogie is as follows: drive eccentric shafts of a front drive eccentric wheel and a back drive eccentric wheel are fixed on one side of the bogie through a bearing and a bearing seat; driven eccentric shafts of a front driven eccentric wheel and a back driven eccentric wheel are fixed on the other side of the bogie through a bearing and a bearing seat; the front and the back drive eccentric shafts are respectively connected with a drive device. The test stand can simulate the vertical vibration, the transverse vibration, the nodding and the compound vibration of the bogie in full range so as to truly measure the fatigue life of the bogie, thereby determine the life cycle, and providing reliable guarantee for the safe operation of the locomotive. The test stand has the advantages of simple structure and convenient operation.
[014] Publication No. CN201251509 relates to a fatigue strength tester of bogie is composed by fixing the active eccentric shaft of a front and a back active eccentric wheel at one side of a bench via a bearing and a bearing base thereof; fixing the inactive eccentric shaft of a front and a back inactive eccentric wheel via a bearing and a bearing base thereof on another side of the bench; and connecting the active eccentric shaft with a drive device. The tester can simulate the vertical vibration, transverse vibration, nodding and composite vibration of a bogie in full frequency range to actually test the fatigue life of a bogie, thereby finding its service life and confirming the safe operation of locomotives. The fatigue strength tester has simple structure and simple operation.
[015] Thus the prior art is primarily of component level Fatigue testing, actuators mounting portal frame and fatigue testing by vibration mode. They include only the ground support items where the reaction forces are resolved with ground for obvious reasons of individual component testing’s. Some of the art claims, portal columns for mounting loading machines, fatigue testing mode, essay assembly for test components, locomotive bogie parts testing by ground mounted methods.
[016] In order to overcome abovelisted prior art, the present invention aims to provide a fatigue test fixture for fabricated metro bogie chassis. It eliminates the wheels and suspensions (shock absorbers) that will be available in a metro coach used for mobility in actual scenario. The wheels make the base unstable and the shock absorbers will absorb the reaction forces during testing and hence the chassis can't be tested as per loads specified in the test standard.
[017] This is a fatigue and static testing of complete Bogies , which supports the entire Metro Bogie Frame. It refers to the hanging level support to simulate the total representation of Metro Bogie, cantilever reactions and hence more realistic.
OBJECTS OF THE INVENTION:
[018] The principal object of the present invention is to provide afatigue and static test loading fixture for fabricated metro bogie chassis.
[019] Another object of the present invention is toprovidea testing set-up which can reproduce the deformation observed in service as closely as possible.
[020] Still another object of the present invention is toprovide metro bogie chassis frame fatigue and static testing loading fixtures and testing components holding fixtures by hanging type.
[021] Yet another object of the present invention is toprovide special fixtures to simulate load conditions that the bogie frame would undergo in real life.
SUMMARY:
[022] The present invention relates to the fixtures for fatigue testing of metro bogie chassis to confirm the bogie frame has adequate strength against test loads. It provides the rigid support for mounting the metro bogie chassis for preparation of the test setup. It eliminates the wheels and suspensions (shock absorbers) that will be available in a metro coach used for mobility in actual scenario. The wheels make the base unstable and the shock absorbers will absorb the reaction forces during testing and hence the chassis can't be tested as per loads specified in the test standard. The bogie frame is of "H" shape, fabricated with two side frames, two tubular transoms and two end beams. After fabricating, the bogie frame is heat treated for removing the residual stress and machined for parts to be installed. The overall frame configuration is provided to permit load transfer throughout the bogie frame.
BREIF DESCRIPTION OF THE INVENTION
[023] It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments.
[024] Figure 1 and 2 shows bogie frame according to the present invention;
[025] Figure 3 shows test setup depicting location and direction of the applied loads according to the present invention;
[026] Figure 4 shows two of the elements holding the frame hanging from the top while the remaining two, located diagonally opposite,
[027] Figure 5 shows two Y-frames are fitted to the axles;
[028] Figure 6 shows lateral force mechanism;
[029] Figure 7 shows lateral force application arrangement;
[030] Figure 8 showstwist load application;
[031] Figure 9 shows the way of applying the load for lozenge load case;
[032] Figure 10- 13 shows the way of applying the loads on ODD.
DETAILED DESCRIPTION OF THE INVENTION:
[033] The present invention provides a fixture for fatigue testing of metro bogie chassis to confirm the bogie frame has adequate strength against test loads. It provides the rigid support for mounting the metro bogie chassis for preparation of the test setup. It eliminates the wheels and suspensions (shock absorbers) that will be available in a metro coach used for mobility in actual scenario. The wheels make the base unstable and the shock absorbers will absorb the reaction forces during testing and hence the chassis can't be tested as per loads specified in the test standard. The bogie frame is of "H" shape, fabricated with two side frames, two tubular transoms and two end beams (fig 1 and fig 2). After fabricating, the bogie frame is heat treated for removing the residual stress and machined for parts to be installed. The overall frame configuration is provided to permit load transfer throughout the bogie frame.
[034] A test setup depicting location and direction of the applied loads is shown in Figure 3. The bogie is fixed using the above mentioned fixtures and tested with 02 actuators for longitudinal loads, 02 actuators for vertical loads, 02 actuators for twist load and 01 actuator for lateral load.
[035] The roller rig has a driven roll which is easy to change to simulate a corrugation rail or a wheel flat or to use an ideal roll. That gives the possibility to test a complete bogie with all attachments to test its reaction against such impacts from the rail or the wheel.
[036] For vertical force application the frame was supported on dummy axles, as it is supported in real operations. These axles were suspended from the top in place of being supported on wheels. Two of the elements holding the frame were rigid columns hanging from the top while the remaining two, located diagonally opposite, were connected to two 50 tonne actuators as shown in Figure 4. To ensure that this arrangement did not constrain any motion that they were not required to do, the actuator tops and the rigid columns were fitted with hinged joints.
[037] For longitudinal force application the testing required application of 5g longitudinal force. In order to simulate this condition, the traction or the longitudinal force was applied to the Y-frames. The Y-frame being connected to dummy axle transferred the force to bogie frame in the same way as would have been in actual operational condition. In order to ensure that both the axles were loaded evenly, two Y-frames are fitted to the axles as shown in the Figure 5 and to generate the required force, the two actuators were used.
[038] For lateral load application to simulate lateral forces on bogie frame, a lateral force mechanism is shown in Figure 6. This arrangement consists of two pipes whose one end was connected to lateral force actuator Fy and other end was attached to centre of the bogie frame. To avoid buckling, two pipes were provided. This also makes structure more rigid and hence lateral forces were evenly distributed.
[039] Lateral force application arrangement is shown in figure 7. To ensure lateral reaction forces which in real life come from rail flanks and transmitted to the bogie frame through wheels and axles to the bogie frame a special rolling mechanism was provided on axles faces. This ensured up and down movement of the axles while constraining any lateral movement.
[040] For twist load application the twist load was applied at two diagonally opposite corners of the bogie frame in vertical direction using two 50t actuators at the dummy axles, which will transfer the load to the bogie frame (Figure 8). This load simulates effect of track warping.
[041] For Lozenge load case application four actuators were mounted for applying load on four wheel locations of dummy axle for lozenge load case. The set up was made to apply load in x-direction. Figure 9 displays the way of applying the load for lozenge load case.
[042] For ODD load case applicationthree actuators were mounted for applying load on Obstacle Deflection Device (ODD) through fixtures. The set up was made to apply load in x-direction (i.e., longitudinal), y- direction (i.e., lateral) and z-direction (i.e., vertical) individually. Figure 10- 13 dictate the way of applying the loads on ODD.
[043] Thus the fixtures holding the metro bogie frame without any ground support, it is hanging type which is very unique to this kind of testing. The main fixtures withstanding the 70 tons load during static and fatigue testing condition. The small fixtures withstanding 40 tons, have been custom-made to provideindividual holding of respective test components to apply the loading in a uniform manner to represent, realistic load patterns
[044] Fixture includes the actual contact surface of the aggregates and applicable Load. The detailed fixture designs were carried-out to the geometric & kinematic conditions of salient features like traction motor inertia load case, driving gear loading case, brake unit loading case, ODD.
[045] The fixtures holding the metro bogie frame for fatigue testing of 10 million cycles without any failures. The main purpose of this fixtures, is to simulate the actual train running conditions and dynamic loading conditions will be represented to derive the actual fatigue, realized by bogie frame.
[046] The testing system reproduces the deformation observed in service as closely as possible. The test fixtures simulates load conditions that the bogie frame would undergo. These fixtures are the vital components for the static and fatigue testing in hanging method with dummy axle for equal load distribution throughout the chassis thereby replicating the actual bogie loading scenario that occurs on rails.
[047] Numerous modifications and adaptations of the system of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the true spirit and scope of this invention.
,CLAIMS:WE CLAIM:
1. A fixtures for fatigue testing of metro bogie chassis to confirm the bogie frame has adequate strength against test loads comprises bogie frame (Fig 1-A) is of "H" shape, fabricated with two side frames (1a,2b), two tubular transoms (3a,3b) and two end beams (4a,4b) (Refer Fig (2)) and after fabricating, the bogie frame is heat treated for removing the residual stress and machined for parts to be installed wherein the bogie is fixed using the above mentioned fixtures and tested with 02 actuators for longitudinal loads, 02 actuators for vertical loads, 02 actuators for twist load and 01 actuator for lateral load. (Refer Fig (3)).
2. The fixtures for fatigue testing of metro bogie chassis, as claimed in claim 1, wherein the roller rig has a driven roll which is easy to change to simulate a corrugation rail or a wheel flat or to use an ideal roll.
3. The fixtures for fatigue testing of metro bogie chassis, as claimed in claim 1, wherein for vertical force application the frame was supported on dummy axles, as it is supported in real operations and the axles were suspended from the top in place of being supported on wheels, two of the elements holding the frame were rigid columns hanging from the top while the remaining two, located diagonally opposite, were connected to two 50 tonne actuators and the actuator tops and the rigid columns were fitted with hinged joints.
4. The fixtures for fatigue testing of metro bogie chassis, as claimed in claim 1, wherein the traction or the longitudinal force was applied to the Y-frames being connected to dummy axle transferred the force to bogie frame in the same way as would have been in actual operational condition. In order to ensure that both the axles were loaded evenly, two Y-frames are fitted to the axles to generate the required force, the two actuators were used. .
5. The fixtures for fatigue testing of metro bogie chassis, as claimed in claim 1, wherein lateral load application to simulate lateral forces on bogie frame, consists of two pipes whose one end was connected to lateral force actuator Fy and other end was attached to centre of the bogie frame.