The TE77 variable speed reciprocating machine is used to assess the dynamic wear and friction performance of lubricants, fuels, materials and surface coatings. The contact consists of a fixed plate and reciprocating pin. Data output is automatically logged using a TE77SLIM Data Acquisition System.
The moving ball specimen is mounted on the carrier head which is mechanically oscillated against the lower fixed flat specimen. The normal load is applied via a spring-balance through a lever and stirrup mechanism. The normal force is transmitted directly onto the moving specimen by means of a needle roller cam follower on the carrier head and a running plate on the loading stirrup. The oscillations are produced by a motor with an eccentric cam, scotch yoke and guide block arrangement. The fixed specimen is held secure within a stainless steel bath that is clamped to a heater block. The bath can be filled with lubricant. The assembly is mounted on flexible supports, which allow free movement in horizontal directions but no movement vertically. This is connected to a stiff piezo-electric force transducer that measures tangential force in both directions.
The possible testing configurations are as follows:
- Shape of contact: nominally point, line, area, piston ring / cylinder liner
- Normal load: 5 to 250N
- Temperature: Room to 250°C;
- Frequency: 0.1 to 50Hz;
- Amplitude: 1 to 15mm in 8 steps or 0.5 to 5mm in 8 steps.
- Lubrication Conditions: Lubricated/Dry
- Method of Lubrication: Immersed, thin layer, drip fed.
- Friction Force: Can be displayed on an oscilloscope but normally logged to file to show friction evolution
- Temperature: Measured using a thermocouple pushed againsed the side of the lower specimnen.
- Contact Potential: Used to observe the performance of lubricant additivesin produce anti-wear and extreme pressure chemical films.
- Wear: Not directly measured but normally used in conjunction with the profilometer and microscope for wear scar evaluation.
An example of a friction evolution graph crated from a 30 minute lubricated test can be seen below. The test was repeated twice. Note that the repeated tests show very similar results.