| 摘要 |
836,682. Gearing for conveying rotary motion. GENERAL MOTORS CORPORATION. May 28, 1958 [June 26, 1957], No. 17003/58. Class 80 (1). In power-assisted or other steering gear wherein a sector 40, Fig. 2, on a rock shaft 42 is engaged by a reciprocable rack 22 the rack or sector teeth, or both, are tapered as shown in Fig. 3 and the rock shaft 42 is axially adjustable to set the required clearance between the teeth by rotation of a bolt 84 whose head 90 is held between a spring 82 and a retainer 94 mounted in the end of the rock shaft. According to the invention the materials of the retainer 94 and head 90 are so chosen that the wear between them as the shaft 42 rocks compensates for the wear between the rack and sector teeth, the shaft 42 being automatically moved axially by the spring 82 as wear proceeds to maintain the desired clearance between the rack and sector teeth. As shown, the rack 22 is reciprocated by a ball nut 28 on a steering shaft worm 26 and is power-assisted, the nut 28 being secured in a recess in a piston 18 integral with the rack 22. Pressure fluid is supplied to one or other side of the piston 18, to assist the steering, by a control valve, Fig. 1 (not shown) responsive to the reactionary thrust on the steering shaft. It is stated that during operation pressure fluid leaks around shaft 42 into chamber 102, Fig. 3, and develops a pressure which accelerates the wear between the retainer 94 and bolt head 90. The retainer 94 is preferably of softer material than the head 90. |
