Mechanical Engineering Design - Journal Bearings |

This page gives the comparative results of using the Raimondi and Boyd charts with the Java applet for determining characteristics of parallel shaft journal bearings with hydrodynamic lubrication.

d, mm | 20 | 20 | 20 | 100 | 100 | 100 | 100 | 40 | 40 | 40 |

length | 5 | 5 | 5 | 100 | 100 | 100 | 100 | 40 | 40 | 40 |

c | 0.005 | 0.005 | 0.005 | 0.05 | 0.05 | 0.05 | 0.05 | 0.04 | 0.04 | 0.04 |

Load | 10000 | 10000 | 10000 | 100000 | 100000 | 100000 | 100000 | 2500 | 2500 | 2500 |

Revs/s | 100 | 100 | 100 | 20 | 20 | 20 | 20 | 30 | 30 | 30 |

Viscosity | 0.01 | 0.01 | 0.01 | 0.1 | 0.1 | 0.1 | 0.1 | 0.0275 | 0.0275 | 0.0275 |

circ ints. | 72 | 180 | 180 | 180 | 360 | 180 | ||||

length ints. | 16 | 16 | 32 | 20 | 100 | 16 | ||||

Iterations | 1000 | 1000 | 1000 | 5000 | 40000 | 2000 | ||||

Oil hole dia, mm | 0.5 | 0.5 | 5 | 5 | 5 | 4 | ||||

Oil press, N/m^{2} |
100000 | 100000 | 100000 | 100000 | 100000 | 100000 | ||||

ecc. ratio | 0.925 | 0.925 | 0.93 | 0.47 | 0.47 | 0.47 | 0.47 | 0.59 | ||

Sommerfeld No. | 0.04 | 0.04 | 0.04 | 0.2 | 0.2 | 0.2 | 0.2 | 0.132 | 0.132 | 0.132 |

Results: | Chart results | Applet results | Applet results | Chart results | Applet results | Applet results | Applet results | Chart results | Applet results | Applet results |

Friction force, N | 10.4 | 10.76 | 16.18 | |||||||

Attitude angle | 17^{o} |
21.8 | 19 | 58.5 | 58.5 | 59.4 | 58.9 | 52 | 52 | |

Resultant N | 8600 | 9769 | 80048 | 99339 | 99923 | 2554 | ||||

Av. Press, MPa | 86 | 97.7 | 8 | 9.93 | 9.99 | 1.596 | ||||

Coef. of Friction | 0.0011 | 0.00104 | 0.001075 | 0.0046 | 0.0045 | 0.00449 | 0.00448 | 0.0066 | 0.00647 | |

Friction power W | 69.1 | 65.5 | 67.6 | 2890 | 2820 | 2820 | 2815 | 61 | ||

Oil flow l/s | 0.0015 | 0.000146 | 0.000146 | 0.02 | 0.0148 | 0.01477 | 0.01478 | 0.00358 | ||

p/p_{max} |
0.155 | 0.153 | 0.153 | 0.46 | 0.454 | 0.431 | 0.461 | 0.4054 | ||

Theta p_{o}, ^{o} |
23 | 22 | 21.6 | 85 | 84.5 | 79.4 | 83.9 | 76 | 70 | |

Theta p_{max}, ^{o} |
7.6 | 7 | 7.6 | 17.6 | 16.5 | 17.4 | 16.9 | 18 | 18 |

These results (and others) tend to show that with a reasonable number of circular and longitudinal intervals, 2000 iterations are normally sufficient to give answers which are converged within close limits, certainly closer than the limits for much of the real data input for the computations.

David J Grieve, CEng, MIMechE, updated: 7th February 2015, 17th December 2009