TM25 - Experiment


A self-contained floor standing apparatus to fully investigate the effects of speed viscosity and load on the pressure distribution in a journal bearing.

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This floor-standing apparatus allows students to study the performance of a journal bearing during different test conditions.

It is a plain steel shaft encased in a clear acrylic shell and directly driven by an electric motor. The bearing is freely supported on the motor shaft and sealed with a rubber diaphragm. The clearance is especially large to clearly show the oil in the bearing. Supplied with the equipment is a container of suitable oil.
A control unit adjusts the motor speed, which can run in both directions. A display shows the motor speed. An adjustable reservoir supplies oil to a low pressure region at both ends of the bearing.

The bearing contains 12 equi-spaced pressure tappings around its circumference and four additional ones along its topside and on a vertical radial plane. All are connected by light and flexible plastic tubes to the rear manometer panel, to clearly show the pressure head of oil at all 16 points at all times.
Students load the bearing by attaching weights (included) to arms connected to the bearing.

A strong steel frame with a worktop holds the bearing, the motor, the manometer panel and the control unit.

Learning outcomes

  • Measuring pressure profiles for chosen conditions and plotting the cartesian and polar pressure curves
  • Measuring pressure profiles for chosen conditions and plotting the theoretical Sommerfeld curve
  • Measurement of shaft speed and journal speed at the critical whirl
  • Observation of oil wedge (film thickness) and hence eccentricity variations for different speeds and loads
  • Observation of the pressure profiles at these conditions
  • Observation of the critical bearing whirl
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