Elasto-hydrodynamic behaviour between the sphere and rotating-glass-plate friction pair

Description:

• Elasto-hydrodynamic lubrication occurs in roller bearings, gear wheels and cam followers, whose contact surfaces are subjected to high loads.
• These surfaces are elastically deformed because of high contact pressures.
• The theory of elasto-hydrodynamics (EHDtheory) takes into consideration the elastic deformation of the bodies in contact with each other and provides a basis for calculating the influence of lubrication on damage to gears and roller bearings.
• The tribological system in TM 260.02allows a clear representation of the elasto-hydrodynamic behaviour of lubricating film layers.
• To do this, the lubricating film between a sphere and a glass plate is determined and studied using a reflected-light microscope.
• The experimental unit contains a rotating glass plate and a steel sphere as the friction pair.
• The steel sphere is pressed against the glass plate from underneath.
• The contact force between the friction partners can be adjusted continuously by means of a lever.
• A lubricating film is located between the sphere and glass plate at the contact point.
• The glass plate is plane-parallel and dielectric coated.
• The surface of the hardened steel ball is polished.
• The reflected-light microscope stands on an adjustable xy cross table and has a focus drive.
• The TM 260drive unit is required in order to conduct experiments.
• The experimental unit is mounted quickly and easily on the frame of the drive unit with quick-action chucks.
• The glass plate is driven by a clampable coupling between drive unit and gear unit.
• The display and control unit of the drive unit shows contact force and speed and allows the continuous adjustment of the speed.
• In the experiment, light waves from the reflected-light microscope pass through the glass plate and the lubricating film and are reflected by the surface of the steel sphere.
• The light waves are refracted in the lubricating film, making colour interference fringes visible.
• The wavelength of light increases or decreases with the variable thickness of the lubricating film.
• The thickness of the lubricating film is determined visually by means of the colour of the interference fringes created.
• The contact force is measured by a force sensor.

Technical Details:

Specifications:

• elasto-hydrodynamic behaviour of a lubricating film layer between sphere and rotating glass plate
• quick and easy assembly of the experimental unit on the frame of the drive unit
• determine the thickness of the lubricating film by optical interference
• glass plate is driven by a clampable coupling between drive unit and gear unit
• hardened steel sphere, polished
• rotating plane-parallel glass plate with dielectric coating
• continuous load on the sphere via lever arm
• load measured by force sensor
• displays of force and speed and speed adjustment on the drive unit

Technical Data:

• Load application device:
  • load: 150N
  • lever arm ratio: 3:1
• Sphere:
  • diameter: 25,4mm
  • hardened steel, polished
• Glass plate:
  • diameter: 150mm, plane-parallel
  • coating: BK 7, dielectric, R=30%
• Microscope:
  • magnification: x50
  • halogen lamp: 10W
• Force sensor: 0…50N

Dimensions & Weight:

• L x W x H: 350x250x550mm
• Weight: approx. 8kg

Learning Objectives/Experiments:

• together with the drive unit:
  • determine the thickness of the lubricating film at the contact point of a sphere with a plane surface – compare with theoretical value
  • study the effect of load and speed on the thickness of the lubricating film

Scope of Delivery:

• 1 experimental unit
• 1 sphere
• 1 glass plate
• 1 set of instructional material

Features:

• investigation of the thickness and shape of the lubricating film

Accessories:

• Required:
• TM 260Drive unit for tribological investigation

Due to the continuous development of our products, the goods supplied may vary in detail to that illustrated on this Website.