Steering encoder units

SKF steering encoder units (fig. 1) are plug-and-play steering input devices for steer- by-wire systems. They combine reliable encoder technology with the simplicity of plug-and-play component packaging.

Designs and variants

SKF steering encoder units are based on well-proven SKF technologies. They have been designed from the inside out, starting with bearing encoder technology, to precisely monitor steering. From there, a friction torque device, mechanical interface for mounting and a shaft to connect the steering wheel are added to create a complete unit. The friction torque device provides feedback to the operator by providing adequate resistance in the steering wheel.

The units contain a sealed SKF Explorer deep groove ball bearing to provide long service life and reliable performance. They do not require any adjustment or relubrication during their expected service life and are considered virtually maintenance-free. They reliably fulfil the demands of industrial and off-highway vehicle steer-by-wire systems.

SKF steering encoder units are supplied ready to mount. Connection to a steer-by-wire system is achieved by plugs. Available steering encoder units are listed in table 1. For additional information about SKF steering encoder units, contact the SKF application engineering service.

Sensor technology and electrical data

SKF steering encoder units use non-contact incremental sensors to track the movement of the steering wheel. These magnetic sensors do not wear, are protected from external influences, and are designed to provide maximum service life. SKF steering encoder units are designed to support the safety requirements of safety related control systems in accordance with ISO 13849. They contain two sets of sensors to provide redundancy.

SKF steering encoder units provide two independent sets of square wave signals (fig. 2) via open collector circuits. They require a regulated voltage supply, which can range from 5 to 12 V DC. Pull-up resistors should be placed between the voltage supply and the conductors for the output signals to limit the output current to 20 mA. Recommended pull-up resistors are listed in table 2. The application load resistance between the ground line and the conductors for the output signals should be at least 10 times higher than the resistance of the pull-up resistor. This keeps the output signals readable.

Units providing absolute position information

For applications where a combination of absolute position information, variable steering feel and active end stops are required, SKF can provide customized steering units. For additional information about available designs, contact the SKF application engineering service.
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