Couplings

Drive couplings – the coupling between electric motor and hydraulic pump

Drive couplings transfer the torque from the motor shaft to the pump shaft and form the mechanical link inside the hydraulic power pack of a tail lift. They sit centred between motor flange and pump body, often embedded in an elastomer jaw ring for torque damping. At SULEJ Ladebordwand you will find drive couplings in different sizes and connection variants, compatible with various market configurations – for backlash-free power transmission in daily lifting and lowering operation.

Design and jaw shape – torque without peak loads

The design varies according to number of jaws, shaft diameter and fit type – common are star-shaped jaw couplings with an elastomer spider that absorbs starting impacts. The inner diameter matches the motor shaft and its keyway profile, the outer geometry matches the pump side. Materials range from die-cast aluminium to steel versions for higher torques. The correct choice of hardness and Shore value of the jaw ring noticeably influences noise behaviour and service life.

Wear pattern and inspection when opening the power pack

Worn drive couplings often stand out through a clacking noise during start-up, through torque loss or through hydraulic oil traces at the power pack flange. When opening the power pack, the jaw edges and the elastomer spider must be inspected – broken edges, cracks or hardening are clear replacement indicators. During installation pay attention to clean shaft fit, correct pressing depth and the specified tightening torque. Careful alignment prevents premature wear on pump bearing and motor bearing.

Benefits at a glance

• Backlash-free torque transmission between motor and pump
• Elastomer damping protects bearings and shaft from starting impacts
• Available in different jaw shapes and shaft diameters
• Easy replacement with opened power pack – without complete removal

A precisely fitting drive coupling ensures smooth power transmission and protects the expensive main components motor and pump from consequential damage.