HSU

High Speed Uniformity Machine (HSU)

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High Speed Uniformity Machine (HSU)

The high-speed uniformity measuring machine type: HSU is used to measure the uniformity of tires on complete passenger car and light truck wheels (Li ≤ 121) under conditions similar to driving conditions.
In addition to the usual TU values, the HSU determines the tangential force fluctuation and its harmonics.
The heating effect of the tire during run-up of the tire to measuring speed (with low lateral force) improves the measuring and repetition accuracy of the measured values without influencing the cycle time, a settling time before the measurement can usually be omitted.

Measurement process

The tire is transported into the machine and centered by the centering unit.
Via the centering unit the outside diameter of the tire is measured.
The measured diameter is compared with the
For a correct measurement process, the tire type needs to be transferred to the machine via a barcode reader (optionally) or the conveyor control system. The tire type or tire number can be edited as well manually via the touch panel.
The road wheel is pressed against the tire by means of a ball screw, according to the given load force.
The values are registered by the load cells and transmitted to the machine control.
Based on the results and set tolerance, the registered values are displayed, compared and transmitted to the machine control.

Applied standard guidelines

2006/42/EG CE machinery directive
WDK-directive 109-2 Uniformity measurement of pneumatic tires – Radial and lateral force variation
WDK-directive 109-3 Uniformity measurement of pneumatic tires – Test condition for passenger car tires
WDK-directive 109-8 Uniformity measurement of pneumatic tires – Test parameters and quality values for passenger car tires.
SAE International J332 – Testing Machines for Measuring the Uniformity of Passenger Car and Light Truck Tires
ISO 13326 Test methods for measuring tyre uniformity