• Tribology and Lubricants
• /
• v.18 no.6
• /
• pp.402-410
• /
• 2002

In this study, a hydrodynamic analysis of the reciprocating compressor crankshaft considering a finite bearing modelling of the journal bearings used in small refrigeration compressors is performed. In the problem formulation of the compression mechanism dynamics, all corresponding hydrodynamic forces and moments are considered using the finite bearing analysis in order to determine the crankshaft trajectory at each step. The solution of the Reynolds' equation is determined numerically using a finite difference method and a Newton-Raphson procedure was employed in solving the dynamic equations of the crankshaft. The crankshaft orbits fur the finite bearing model and short bearing theory were used to compare the effect of the hydrodynamic farces of the journal bearings on the dynamic and lubrication characteristics of the crankshaft-journal bearing system. Results show that the finite bearing model for the journal bearings must be considered in calculating for the accurate dynamic characteristics of the reciprocating compressor crankshaft.

• Tribology and Lubricants
• /
• v.20 no.3
• /
• pp.119-124
• /
• 2004

Engine bearing system is generally affected by aeration. In this paper, the aeration effects on the engine crankshaft bearing system were studied. To do this, unsteady oil flow analysis on the engine crankshaft oil circuit system was carried out. And aeration effects on the bearing system were simulated to figure out lubrication characteristics of the each bearing such as oil flow rate, minimum oil film thickness, friction loss and increase of oil temperature.

• Journal of KSNVE
• /
• v.10 no.1
• /
• pp.97-106
• /
• 2000

The dynamic behavior of crankshaft-bearing system in scroll compressor has been investigated using the combined methodologies of finite elements and transfer matrices. The finite element formulation is proposed including the field element for a shaft section and the point element at balancer weight locations, bearing locations, etc., whereas the conventional method is used with the elements. The Houbolt method is used to consider the time march for the integration of the system equations. The linear stiffness and damping coefficients are calculated for a finite cylindrical fluid-film bearing by solving the Reynolds equation, using finite difference method. The orbital response of crankshaft supported on the linear bearing model is obtained, considering balancer weights of motor rotor. And, the steady state displacement of crankshaft are compared with a variation in balancer weight. The loci of crankshaft at bearing locations are composed of the synchronous whirl component and the non-synchronous whirl component.

• Tribology and Lubricants
• /
• v.22 no.4
• /
• pp.203-210
• /
• 2006

Two kinds of crankshaft oil supply system which were called continuous and discontinuous oil sup-ply system have recently been adopted in engine developing process. In order to clarify the lubrication characteristics for theses systems, in this paper, the comparison studies on supplied oil temperature, pressure, aspect ratio of bearings, and radial clearance were carried out for the main and the connecting rod bearing using computational fluid dynamic analysis.

• Tribology and Lubricants
• /
• v.20 no.1
• /
• pp.27-32
• /
• 2004

This paper presents unsteady oil flow behaviors in the engine lubrication network to clarify the differences between continuous and discontinuous oil supply crankshaft system. Using commercial network analysis program, Flowmaster2, engine lubrication network system analysis were carried out. And effects of crankshaft speed and supplied oil pressure on pressure fluctuation in oil groove and oil flow rate to each bearing were analyzed.

• Tribology and Lubricants
• /
• v.11 no.5
• /
• pp.162-171
• /
• 1995

The application of reciprocating engine crankshaft bearings is of particular importance and interest among the plain bearing, not only because the sheer volume of intemal combustion engines now produced, but because the severe operating conditions they are subjected to. Demands for better performances of crankshaft bearings have provide an important impetus in the development of bearings and bearing materials. As engine design progresses toward higher outpt and higher efficiency, crankshaft bearings must perform under more seveve operating conditions. Higher load, temperature, and speed as well as lower viscosity oil are applied to the bearing sysem, resulting in a smaller minimum oil film thickness. This means more solid-solid contact between the shaft and bearing, and the bearing is exposed to more danger of seizure. Some engines may experience bearing seizure problems. However, understanding about the seizure behavior and mechanism is far from being enough. Seizure resistance of a bearing-shaft system will be affected by the properties of the shaft and bearing, especially their materials and surface texture. Commonly used engine bearing materials include Al-Pb-Si, Al-Sn-Si, Al-Sn, and Cu-Pb with Pb-Sn-Cu overlay. These materials have very different properties. They showed different behaviors dering seizure tests and seizure may occur with different mechanism for different bearing material. Shaft materials also affect the seizure resistance of the system. Surface texture of the bearing and shaft have apparent effects on the lubrication and solid-solid contact pattern, and therefore will affect the seizure behavior of the system. Bearings and shafts which are made of different materials and have different surface textures have been tested and analyzed. Their effects on seizure resistance are discussed and possible seizure mechanisms for different beatings are presented in this paper.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.26 no.8
• /
• pp.1585-1590
• /
• 2002

This paper reports on the balance weight effect on the lubrication and friction characteristics of crankshaft system. To determine the main bearing loads, the crankshaft was treated as statically determinate system. Four and eight-balance weight crankshafts were considered, and minimum oil film thickness and friction loss were calculated. The main bearing loads were increased in the four-balance shaft due to the increasing of unbalanced rotating mass at No. 1 and 3 main bearing sides. The minimum oil film thickness of four-balance shaft became thinner than eight-balance, and friction loss was increased.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1996.05a
• /
• pp.41-46
• /
• 1996

For a vertical type crankshaft-journal bearing system used in scroll compressor, nonlinear transient response analysis is applied includung nonlinear fluid film reaction forces of journal beatings. By a connected behavior analysis of crankshaft and orbiting scroll, the radial clearance of scroll wraps is calculated. Considering tangential leakage for this clearance, a coupled analysis model for leakage and dynamic behavior of the orbiting scroll is made, and analyzed by iterative calculation. By regarding clearances of main, sub bearing of crankshaft and orbiting scroll shaft bearing clearance as design parameters, the radial clearance of scroll wraps is analyzed.

• Tribology and Lubricants
• /
• v.11 no.1
• /
• pp.44-49
• /
• 1995

Friction characteristic of an engine crankshaft bearing is affected by revolution speed, applied loads, and viscosity of lubrication. So, experimental investigation is required to observe the friction characteristics using these factors. Hydraulic cylinder, servo controller system which can be modified the applied load, and test rig for the observation of the characteristics of engine crankshaft bearings were designed and fabricated, and some experiments were performed. Friction torque, journal locus and circumferential temperature variation of crankshaft bearing were measured according to applied load, revolution speed, and oil inlet temperature.

• Tribology and Lubricants
• /
• v.20 no.2
• /
• pp.84-90
• /
• 2004

It is very important to improve the durability and reliability of crankshaft because of conflicting demands for lower fuel consumption and higher power output. In this study, for the crankshaft bearing design, analyses were conducted to determine the lubrication characteristics such as oil flow rate, minimum oil film thickness, friction force and increase of oil temperature at main bearing and connecting rod bearing. Additionally, supplied oil pressure and temperature effects on the bearings were simulated to figure out lubrication characteristics on the bearings. Finally the effects of increasing the bearing width and clearance were introduced on the lubrication characteristics.