| 摘要 |
1,126,071. Flexible shafts ; collapsible shafts. BIRFIELD ENG. Ltd. 9 Jan., 1967 [12 Jan., 1966], No. 1381/66. Heading F2U. [Also in Division B7] A motor-vehicle telescopic flexible steering column shaft which will collapse under vehic e impact and which also reduces noise transmission from the engine compartment, comprises a hard rubber or polyurethane sleeve 4 fast in a tubular outer shaft 3 with a solid rectangular cross-section inner shaft 2 axially slidable in the sleeve 4. The sleeve may be moulded directly in the tubular outer shaft 3 or may be moulded separately in one or more parts with one or more projections 9 which register in corresponding side holes 12 in the wall of the tube 3, the sleeve being collapsed to allow the projections to enter the tube and spring outwards into the holes before the inner shaft 2 is fitted. The inner surface 7 of the sleeve is coated with P.T.F.E. by bonding or impregnation, the surface 7 also having longitudinal lubricant reservoir recesses 8 packed with grease on assembly. A staked projection 15 or peened rivet (Fig. 4, not shown) retains the assembly during storage &c. As shown, the outer tubular shaft 2 may also be rectangular in cross-section whereby the sleeve 4 is in torque-transmitting compression and the joint fails-safe in the event of rupture of the sleeve 4, or, the outer member may be of elliptical cross-section (Fig. 5, not shown) whereby the sleeve 4 is in torque-transmitting shear. In Figs. 6 and 7 (not shown), steel rollers (22) in the flat plastics cages (23) are interposed between the inner shaft 2 and longitudinal recesses (20) in the sleeve 4 to increase torsional stiffness and reduce axial sliding friction, the bases of the recesses (20) being lined with shim steel to further reduce rolling resistance of the needle rollers and also prevent roller indentation in the recesses base surfaces. Conventional yoke members 1 of Hook's type joints are secured to the ends of the shafts 2, 3, the latter of which may be additionally lined beyond the sleeve 4 with foamed synthetic plastics material acting as a further noise damper. |
