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TM 280 Pressure distribution in journal bearings



  • Ideal observation of the function thanks to transparent bearing housing1
  • Clear representation of the radial and axial pressure distribution in the journal bearing1
  • Investigation and visualisation of instability in journal bearings


Technical Description

In hydrodynamic journal bearings the shaft and the bearing shell are separated from each other during operation by a lubricating film. The supporting function of the lubricating film in the journal bearing can be described by the pressure distribution in the bearing gap. 

The TM 280 unit is used to visualise the axial and radial pressure profile in the journal bearing with hydrodynamic lubrication. To do this, there are 12 measuring points around the circumference of the bearing shell and 4 measuring points in the longitudinal direction. The respective pressures can be read via 16 tube manometers with reference to the height of the liquid column.

The journal bearing consists of an electrically driven journal that rotates in a freely movable bearing housing. Oil is used as the lubricant. The displacement of the shaft journal depending on the speed and direction of rotation as well as the characteristic behaviour during start-up can be observed through the transparent bearing housing. 

Speed and direction can be adjusted. The load can be adjusted by varying the weights supplied with the unit. The temperature in the bearing gap is measured in order to determine the viscosity of the lubricant.

The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.

Learning Objectives / Experiments
- displacement of the shaft journal as a function of the speed
- pressure distribution in the bearing under constant load and different speeds
- critical speed as a function of the load
- critical speed as a function of the oil temperature


[1] visualisation and investigation of pressure distribution in journal bearings
[2] bearing housing is completely transparent
[3] bearing housing moves freely on the rotating journal
[4] infinitely variable speed, electronically controlled
[5] load on the bearing via set of weights included with the unit
[6] temperature measurement in the bearing housing
[7] radial and axial pressure distribution indicated with 16 tube manometers
[8] digital display for speed on the display and control unit

Technical Data
- nominal bearing diameter: 51mm
- bearing gap: 4mm
- bearing width: 75mm
- bearing load: 6,7...16,7N
- power: 0,37kW
- max. speed: 3000min-1
Oil ISO viscosity grade: VG 32
Tank for oil: 2,5L
Set of weights
- 1x 1N (hanger)
- 2x 2N
- 1x 5N

Measuring ranges
- pressure: 1770mm oil column
- temperature: -10...50°C
- speed: 0...3000min-1

Dimensions and Weight
LxWxH: 1100x750x2650mm
Weight: approx. 110kg Required for Operation 230V, 50Hz, 1 phase or 230V, 60Hz, 1 phase

Scope of Delivery
1 trainer
1 display and control unit 
1 set of tools
5L hydraulic oil
1 hand-held temperature measuring device
1 set of instructional materials

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