Trw Limited

Zf Automotive UK Limited

James Stephen Ironside

Stephen David Butler

Robert Hill

Matthew Larner

Jose Martins

Andrew Paul Smith

A torsion bar assembly comprises an input shaft, an output shaft, and a torsion bar that connects the input shaft to the output shaft. An end stop face on the input shaft that co-operates with a respective end stop face of the output shaft to limit an angular deflection of the torsion bar assembly in a first direction away from the neutral position and an end stop face on the input shaft that co-operates with a respective end stop face of the output shaft to limit an angular deflection of the torsion bar assembly in a second direction that opposes the first direction. A first alignment feature is provided at or close to the end of the input shaft nearest the output shaft and a second alignment feature is provided at or close to an end of the output shaft nearest to the input shaft, the first alignment feature facing the second alignment feature across a gap. The alignment features each define respective contact surfaces such that if the input shaft and the output shaft are pressed axially towards each other to close up the gap the contact faces co-operate to set relative angular positions of the input shaft and the output shaft to correspond to a neutral position.

Torsion bar assembly and method of assembling same

A torque sensor for use in an electric power assisted steering system comprises a first shaft, a second shaft, and a torsion bar, a hollow sleeve that is secured to the first shaft and extends along the torsion bar to at least partially axially overlap the second shaft, angular deflection indicating means that produce a signal that is dependent on the angular deflection of the first shaft relative to the second shaft as a torque is applied across the torque sensor that causes the torsion bar to twist, at least one drive dog fixed to the sleeve and at least one corresponding drive dog fixed to the second shaft, in normal operation the two dogs being offset so that they permit a defined range of angular deflection of the torsion bar but will engage each other to provide a path for torque to be transferred from the first shaft to the second shaft in the event of a failure of the torsion bar, and a connecting element which has a first part that is secured within a bore in one of the second shaft and the sleeve, the connecting element having a second part that extends into a feature of the other of the second shaft and the sleeve, at zero torque across the torque sensor the connecting element being spaced circumferentially from the feature by an angular distance greater than the spacing between the drive dogs and spaced from the feature in a direction along the axis of the shafts that is less than the overlap of the drive dogs in that direction to prevent the shafts moving apart in the event of failure of the torsion bar by an amount that would otherwise prevent the drive dogs engaging.

Torque Sensors

Growing community of inventors

Birmingham, United Kingdom

James Stephen Ironside