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Optimal Seal Combination Through Systematic Tests

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Optimal Seal Combination Through Systematic Tests
Optimal Seal Combination Through Systematic Tests

Video: Optimal Seal Combination Through Systematic Tests

Отличия серверных жестких дисков от десктопных
Video: Effective Unit Testing by Eliotte Rusty Harold 2023, January
Anonim

Two extremely different parameters collide between the seal and the piston rod: the frictional force of the seal and the tightness on the rod. But wear, positioning and repeatability, maximum and minimum speed, stick-slip behavior, minimum and maximum pressure, suitability for certain fluids, including Skydrol or water-based fluids, as well as limit values ​​for contamination of the fluid are other important parameters.

Added to this are the different sealing systems: classic seals with sealing and scraper rings and non-contact seals with a hydrostatic piston rod guide or with an annular gap seal. With classic seals, different sealing materials play a role, as does the geometry - especially that of the sealing edge.

However, the nature of the counter surface, for example the piston rod, and the friction and lubrication properties of different media are also decisive. This includes chrome-coated steel or light metals, but also modern materials with a special plastic coating such as H-CFRP, the composite material from Hänchen made of carbon. The surface processing methods such as honing or grinding these materials also have an effect on the sealing effect.

Test bench for systematic tests

In order to be able to test the purchased seals for its own hydraulic cylinders efficiently and in a practical manner, Hänchen developed its own test bench with its Ratio-Drive drive system.

The core element is four hydraulically operated test axes, each of which tests two test chambers with defined seal combinations. All four axes can be operated with different test specimen types and parameters. The stroke of the system can be selected according to the rod. Speeds of up to 4 m / s are possible. With self-sufficient parallel operation of all 4 rods, up to 1 m / s can be driven, the frequency can be up to 5 Hz.

The seal test bench enables tests according to VDMA 24577 to determine the frictional force. The pressure in the test chamber can be up to 600 bar and can be regulated during the movement, so that realistic conditions can be mapped. The motion profile is designed for sinusoidal or constant speeds. The acceleration phase can also be parameterized. Any rods with any combination of seals can be attached as test objects and tested with a wide variety of fluids.

Content of the article:

  • Page 1: Optimal seal combination through systematic tests
  • Page 2: Data acquisition and evaluation
  • Page 3: External testing services

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