Roller Encoder Units

SKF roller encoder units (fig) are the optimal solution for applications requiring outer ring rotation. They are capable of detecting linear speed, direction and distance.

For example, they are widely used for the mast height control in forklift trucks. The units interface directly with the vehicle controller to provide useful information to the operator. They generate an electronic signal that can be used to determine

• relative position of the mast
• direction that the mast is moving
• speed and acceleration of the mast.

An SKF roller encoder unit is based on a 6201 sealed deep groove ball bearing with a 32 mm outside diameter, making it easy to incorporate into many designs. These robust units offer high signal accuracy within a compact bearing envelope. They can be easily integrated into pulleys, cams, rollers or wheels, providing an encoder assembly with an outer ring rotation.

SKF roller encoder units are available in different designs, including:

• A spring-loaded cam arrangement, using spring force to press the motor encoder unit against a moving component. The mechanical interface of the cam roller unit, which can be customized to meet OEM requirements, is directly driven by the moving counter surface.
• A pulley arrangement, driven either by a wire or belt that has been incorporated into the design of the mast height positioning system.

Active sensor design

An SKF roller encoder unit incorporates a compact, robust active sensor, that functions as an incremental encoder. Its main components are the magnetic impulse ring and sensor cells embedded in a body with connecting cables.

The digital output signal is equal to the number of pole pairs on the impulse ring. This is transmitted to an electronic processing control unit, and provides information about the length over which the unit has moved, speed and acceleration of the counter surface, e.g. the mast on a forklift. This enables accurate mast height control, which is particularly important to those operations that demand speed and accuracy from the operator, or the need of preprogrammed operating cycles. The roller encoder unit�s output signals may also be used for simple digital read-out systems or to trigger other safety systems.

Designed for demanding applications

The SKF roller encoder unit is designed primarily to increase operator efficiency. It also has applications well beyond fork lift trucks. They can be adapted to agricultural, forestry, mining and construction equipment and a variety of other industrial applications, such as escalators or sliding doors.

Additional designs of roller encoder units can be developed based on specific requirements. For detailed information about these units, contact the SKF application engineering service.