DESIGN OF A TEST BENCH FOR THE TILTING BOLSTER OVER THE BOGIE

Transcription

1 DESIGN OF A TEST BENCH FOR THE TILTING BOLSTER OVER THE BOGIE Gabriel Gomes Gameiro (Extended abstract for MSc Thesis in Mechanical Engineering) Instituto Superior Técnico, Technical University of Lisbon Lisboa, Portugal; gabrielgameiro@gmail.com Abstract This paper present the design of a test bench for the tilting bolster over the bogie of the tilting train CP 4000 of the company CP- Comboios de Portugal, E.P.E. This test will serve to observe/measure the angle of inclination of the Load Bolster in relation to the Tilting Bolster and the angles of the relative positions of the connecting rods. The main objectives of this project are: 1) Design the test bench based on Standards/Codes of the Mechanical Engineering Design; 2) Develop a new procedure/methodology for observation/measurement the angles of the relative positions of the Bolsters and the connecting rods; 3) Analysis of manufacturing costs of the test bench. This design was inspired by a need of the EMEF, S.A. Company to obtain one test bench that is able to replace manual stay work methods. In this slow way of work it is used a coordinate measure laser machine. This test bench is composed by a support structure of the tilting bolster over the bogie and by a work station that includes a hydraulics power unit to operate the hydraulic tilting cylinders to tilt the Load Bolster and an electronic control unit to allow that one computer controls the hydraulic circuit and measure the angles. In the design of the supporting structure, there was a check of the forces involved and it was made a structural analysis of the structure by means of method based on Eurocode 3 and a numerical method (finite element method). In the hydraulic circuit and electronic unit, were selected all the components that constitute it. In conclusion, it is presented a test bench and a new methodology for measuring the angles that satisfy the requirements and constraints specified in design. Keywords: Test Bench, Train, Active Tilting, Structural Design, Eurocode 3, Oil-Hydraulic Introduction Design Objective The test bench for the tilting bolster over the bogie complements the equipment necessary to EMEF company to ensure the quality of services provided in the maintenance of trains, once EMEF company has a quality management system certified since the year 2000, currently as the norm NP EN ISO 9001: 2008, covering all of its field of activity in all its establishments. In this case, this 1/10

2 equipment is used for testing the tilting bolster over the bogie of tilting train's CP 4000, property of the company CP-Comboios de Portugal, E.P.E. more efficient. These test methods need improvement to reduce the time to perform testing and to make it The aim of this project is a test bench that using the hydraulic cylinders of the same bogie actuated by an oil hydraulic circuit. It simulates the movement of tilting train and checks the relative positions of the four connecting rods, all through a computer that controls the oil hydraulic circuit and constantly reads the angle between the Tilting Bolster and Load Bolster until reaches 8 degrees. Once this value is obtained, the computer must verify the angular displacement of the four rods and compare them with results given by the manufacturer (31 and 25 degrees). Description of Test Performing Currently At the moment, to measure the relative angles of the four connecting rods and the 8 degrees between the Tilting Bolster and Load Bolster is used a coordinate measuring laser machine. The use of this machine requires that the object to verify remains fixed, since it measures all the distances in relation to its position. Subsequently the desired measure is computed. With the requirement of having the object to measure remains fixed, the company has built a structure to support the tilting bolster over the bogie, illustrated in figure 1. Figure 1. The existing structure supporting the tilting bolster over the bogie This structure is used to determinate the drilling stops signs of secondary suspension to fix the assembly to the frame by 8 bolts. This framework has some disadvantages: The procedure to set in place the structure and fix it with bolts is a time consuming method and requires a meticulous work; Requires two operators, so that with a load lifting device, place the assembly on the support and align the holes for the bolts are placed; Does not guarantee stability in order to prevent rollover in case of an accident. 2/10

3 First, to tilt the load Bolster 8 degrees, is used a crane and the angle between the Bolsters is frequently measure till the specified angle is reached. Since this method was very time consuming, some special tools were developed to make easy the all procedure. Figure 2. Special tools used on the current tests Project Specifications Project Requisites i. The test bench must have the ability to tilt the Load Bolster 8 degrees in relation to the Tilting Bolster. ii. The test bench should be designed by the standards and codes of design. iii. Use of standard components and profiles. iv. The test bench should be as light as possible. v. The test bench should be transportable. vi. The test should be done automatically and in a short time. vii. The console will also have manual control devices. viii. The Unit Control should have an emergency stop device. ix. The devices must be marked clearly and have good visibility. x. Automatic issuing of test reports. Project Constraints i. The measurement of the angles should be as accurate as possible. ii. The structure must support the tilting bolster over the bogie and remain stable in emergency situations. iii. The structure should be rigid. iv. The minimum thickness of the components should be 4mm. 3/10

4 Solution Found Gabriel G. Gameiro Support structure of the tilting bolster over the bogie Figure 3. New structure obtained by the design This structure meets all the requirements and constraints numbered in the previous section and its main features are: Weight: 178 Kg Maximum width: 2000 mm Maximum height: 1108 mm Maximum length: 2444 mm Item Constituted essentially by elements with profiles UPN 80 e L30x30x4 Two eyebolts to lifting and to transport the structure. Description 1 Transverse Beam Base 2 Reinforcement Bar of stability 3 Support 4 Column 5 Lifting Eyebolt 6 Shell to fixed the supports Reinforcement bar of transverse 7 stiffness Reinforcement bar of longitudinal 8 stiffness 9 Longitudinal Beam Base Table 1. Legend of figure 3 Rod Tilting Bolster Load Bolster Figure 4. New structure supporting the tilting bolster and the load bolster over the bogie 4/10

5 Control Unit After performing the steps of the design of control unit, it was obtained one solution for the portable table, one solution to hydraulic circuit and one solution to electronic circuit. 1. Portable Table: Figure 5. Concept of the portable table with the control unit This portable table has a lower compartment to place the hydraulic system (power group + valve group), a base for placing a laptop computer and a set of buttons (emergency button and buttons for manual operation of valves). As the manufacture of this portable table will be more expensive than buying one in the market that fits the same circumstances, it was opted for to buy the table which is illustrated in Figure 6. Figure 6. Portable table to buy This table is manufactured by FACOM Company with the reference 2703PB and has the following characteristics: Dimensions (L x W x H): 1092 x 617 x 903 mm Weight: 54,0 Kg operation. In this car will be adapted the hydraulic circuit, the electronic circuit and the buttons for manual 5/10

6 2. Electronic Circuit: The electronic circuit is composed by one chain of measurement and one chain of actuation, both connected to a Bus-Powered Multifunction DAQ for USB (NI USB-6008) for one computer with software developed in LabView control the test. The chain of actuation is illustrated on the figure 7. It has two relays to act the hydraulic valves because the DAQ doesn t have electrical power to act the valves directly. Figure 7. Chain of actuation The chain of measurement is illustrated on the figure 8. It s composed by one sensor (inclinometer) that measure the require angle and the signal conditioning to convert the output signal of inclinometer (4 20 ma) in the signal accepted by the DAQ ( V). The electronic circuit has six chains of measurements. All of them have de the same signal conditioning but two have inclinometers that measures angles between -15º and +15º for the plates and four have inclinometers that measures angles between -45º and +45º for the rods. Figure 9 presents the signal conditioning. Figure 8. Chain of measuring Figure 9. Signal conditioning 6/10

7 3. Hydraulic Circuit: The solution for the hydraulic circuit is shown in Figure 10. Item Description 1 Reservoir - 40 L 2 Oil Filler Cap 3 Optical Level Indicator 4 Electrical Motor - 500W 5 Gear Pump 6 Return Filter 7 Pressure Filter 8 Pressure Gauge (0-60) bar 9 Pressure Relief Valve 10 Compensated Flow Control Valve 11 Solenoid Valve 12 Directional Valve Tray 13 Pilot Check Valve sandwich 14 Quick Coupler (3/8'') 15 Hydraulic Cylinder Table 2. Legend of hydraulic circuit Figure 10. Scheme of hydraulic circuit 7/10

8 Methodology This project is divided into 2 parts: Design to supporting structure of the tilting bolster over the bogie and the control unit with the hydraulic and electronic circuit. Design of support structure of the tilting bolster over the bogie: 1. Concept generation: In the first step, we surveyed the advantages and disadvantages of the existing support structure in EMEF Company. As the structure had very significant disadvantages, it was developed a new structure in order to supress these disadvantages. 2. Structural optimization and verification: After generating the concept of the new structure, we proceeded to the structural optimization and verification, first, by the analytical method following the advice of Eurocode 3 and later by the numerical method (finite element method) using the software ANSYS. It was verified the resistance of all the elements of the structure and the strength of the connections. In the end it was compared the results of the two methods to check the reliability of the implemented solutions. Unit Control Project The project consists of a portable table that supports a hydraulic power group and an electronic circuit required to measure the angle and controller the hydraulic circuit. 1. Generation of the concept of the portable table: To generate the concept of the portable table, was raised all the requirements and design constraints imposed by EMEF Company. Once generated the concept, came to the conclusion that it was all worthwhile purchase a portable table on the market that it is less expensive than to manufacture one. 2. Project of the hydraulic circuit: The amount of force needed to tilt the load plate was estimated that with the time of tilting, be calculated the values of pressure and oil flow necessary to choose a pump and motor to ensure the necessary strength in the cylinders. A supplier of hydraulic valves, filters and other components of the hydraulic circuit was consulted in order to make a shopping list and a cost estimation for the assembly of the hydraulic circuit. 3. Electronic circuit: Another important step was the design of electronic circuitry of the test bench, the measuring chain and the chain of actions controlled by a computer through a software created in LabVIEW. Several catalogues from suppliers of electronic components were consulted to identify the purchase, including the best sensors to use to measure the required angles. Chains were designed to measure and action have been identified the major 8/10

9 components of electronic circuit and drew up a cost estimation for the manufacture of the circuit. RESULTS In the structural verification by the analytical method, it s used the following scheme forces, as illustrated in figure 11. Figure 11. Scheme of forces actuating on the structure As a simplification, it was assumed that the components c, e and f are bars and the components a, b and d are beams. The value of the length L of the component a is obtained considering that the structure is still stable when is tilted 45 degrees. This value equals 2000 millimetres. The results obtained by this method are resumed on table 2. Component Von Mises Stress Safety coefficient Allowable Stress b MPa 13.2 c MPa 20.0 d MPa MPa e MPa 23 f MPa 7.1 Table 3. Results of the von Mises Stress Through numerical analysis using the finite element method, it was obtained the following stress distributions and displacement distribution, see figures 12 and 13. Figure 12. Stress distributions obtained by finite element method 9/10

10 Figure 13. Displacement distribution References [1] NP EN 1990, Eurocódigo - Bases para o projecto de estruturas, Dezembro 2009 [2] NP EN 1993, Eurocódigo 3 Projecto de estruturasde aço (partes 1 e 8), Março 2010 [3] Parlamento Europeu e do Conselho de 17 Maio de 2006, "Directiva 2006/42/CE," Jornal Oficial da União Europeia de 9 de Junho de 2006, no. Directiva europeia relativa às máquinas. [4] NP EN ISSO 13920:1996, Soldadura-Tolerâncias gerais para construção soldada, Março 2006 [5] Chagas. (2º Edição 2002) Manual Técnico de Produtos Siderúrgicos. [Online]. ( Abril de 2011) [6] Grupo Ferpinta. Catálogo de Produtos Siderúrgicos [Online] (Abril de 2011) [7] J. N. Reddy, An Introduction To The Finite Element Method, Third Edition ed. McGraw-Hill Science Engineering, December [8] F. P. Beer and E. R. Jonhston, Mechanincs of Mateials. 4º edição, McGaw-Hill, J. E. Shigley, C. R. Mischke, and R. G. Budynas, Mechenical Engineering Design. 8ª edição, McGraw-Hill, 2008 [10] A. Silva, J. Dias, and L. Sousa, Desenho Técnico Moderno. 5ª Edição LIDEL, [11] K. Ogata, Engenharia de Controle Moderno. 4ª Edição Pearson Prentice Hall, 2003 [12] MRA-Instrumentação. Catálogo de sensores [Online] (Junho de 2011) [13] RS - Components. Distribuidor de componentes electrónicos [Online] (Junho de 2011) [14] Legrand. Catálogo de componentes eléctricos [Online] (Junho de 2011) [15] Cudell. Óleo-Hidráulica/Automação Industrial. Catálogo 2011 [16] Facom. Catálogo Acções Especiais /10