www.ijatir.org ISSN 2348–2370 Vol.09,Issue.06, May-2017, Pages:0832-0839 Copyright @ 2017 IJATIR. All rights reserved. Design SND Analysis of Two Wheeler Rocker ARM P. PRASAD Assistant Professor, Dept of Mechanical Engineering, GIITS Engineering College, Aganampudi, Visakhapatnam (Dt), AP, India, E-mail: [email protected]. Abstract: Rocker arms are part of the valve actuating mechanism. A rocker arm is designed to pivot on a pivot pin or shaft that is secured to a bracket. The bracket is mounted on the cylinder head. One end of a rocker arm is in contact with the top of the valve stem, and the other end is actuated by the camshaft. In installations where the camshaft is located below the cylinder head, the rocker arms are actuated by pushrods. The lifters have rollers which are forced by the valve springs to follow the profiles of the cams In this thesis, finds the various stresses under extreme load condition. For this we are modeling the arm using design software and the stressed regions are found out using ANSYS software. Here in this thesis we are observing that by changing different materials(carbon steel, HMCF UD & Aluminum alloy7075). In this thesis the static analysis to determine the stress, deformation and strain at different materials. Modal analysis is determining the deformations and frequency at different mode shapes. Fatigue analysis to estimate the life of the component 3D modeling done in CREO parametric software and analysis done by the ANSYS software. Keywords: Finite Element Analysis, Rocker Arm, Static And Model Analysis. I. INTRODUCTION A. Rocker ARM A rocker arm is an oscillating lever that conveys radial movement from the cam lobe into linear movement at the poppet valve to open it. One end is raised and lowered by a rotating lobe of the camshaft while the other end acts on the valve. When the camshaft lobe raises the outside of the arm, the inside presses down on the valve which is used for opening the valve. When the outside of the arm is permitted to return due to the camshafts rotation, the inside rises, allowing the valve spring to close the valve. B. Working Concept of Rocker ARM The drive cam is driven by the camshaft. It pushes the rocker arm up and down about the rocker shaft. Friction may be reduced at the point of contact with the valve stem by a roller cam follower. A similar arrangement transfers the motion via another roller cam follower to a second rocker arm. This rotates about the rocker shaft, and transfers the motion via a tappet to the poppet valve For car engines the rocker arms are generally steel stampings, providing a reasonable balance of strength, weight and economical cost. Because the rocker arms are reciprocating weight, excessive mass especially at the lever ends limits the engine's ability to reach high operating speeds. Truck engines use stronger and stiffer rocker arms made of cast iron or forged carbon steel. Energy is required to move a rocker arm and depress a valve; their weight can be an important consideration. If a rocker arm is excessively heavy, it may require too much energy to move. This may prevent the engine from achieving the desired speed of rotation. Fig.1. C. Variable Valve Actuation Variable valve actuation (VVA) technologies are used to flexible the engine’s valve train by introducing variable valve event timing, duration or lift. The main type of VVA technologies include valve timing control (VTC), variable valve lift (VVL) and cam less valve trains. A rocker arm is used to operate variable valve lift. In variable valve lift operating system, there is two type of lift will be gotten as a minimum lift and a maximum lift. Such operating system is known as 2 step valve train system. This rocker arm which is used in such system is known as 2 step rocker arm. It’s named by its working operation. A 2-step Valve train system is developed that features switchable rocker arms on all intake valves and solenoid-actuated oil control valves (OCV). Fig.2 shows a sectional view of the 2-step system. It is a 2 step valve train system with hydraulic lash adjusters (HLA).
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www.ijatir.org
ISSN 2348–2370
Vol.09,Issue.06,
May-2017,
Pages:0832-0839
Copyright @ 2017 IJATIR. All rights reserved.
Design SND Analysis of Two Wheeler Rocker ARM P. PRASAD
Assistant Professor, Dept of Mechanical Engineering, GIITS Engineering College, Aganampudi, Visakhapatnam (Dt), AP, India,