| 摘要 |
<p>1,133,361. Toothed gearing; screw-and-nut gearing; change-speed gears. M. R. KUEHNLE. 10 Feb., 1966 [11 Feb., 1965], No. 5981/66. Headings F2D and F2Q. A mechanical power transmission comprises a shaft or ring 18 extending along the central axis of a helical race 36, a bearing 16 engaging the race and rotatable about the shaft or ring but not movable along the axis thereof, rotation of the bearing 16, e.g. by a worm 11, causing the bearing to advance relative to the race to transmit power to an output member. In the reduction or step-up gear shown, a multi-start globoidal worm 11 on a shaft 12 engages balls 43 rotatably housed at the outer peripheries of the outer races (42), (Fig. 5, not shown), of ball-bearing units 16 whose inner races (38) are non-rotatably mounted on a ring 18 between spacing blocks 46 clamped to the ring and having arms 56 secured to a hub 58 on a shaft 24, the balls 43 also engaging helical races 36 of a toroidal reaction member 37 secured in a casing 22. Rotation of shaft 12 causes rotation of the bearing unit outer races (42) about their axes, the helical races 36 causing the units 16 to move around the toroidal member 37 carrying with them the ring 18, to rotate the shaft 24. To allow for the pitch of the worm, the bearing units 16 are not equispaced round the ring 18, but have at least one spacing greater than the others, e.g. with 12 units, eleven spaces of 29 degrees 10 minutes and one of 40 degrees, or ten spaces of 29 degrees 10 minutes and two of 35 degrees diametrically opposed. Modifications.-A disc secured to the shaft 12 and having spiral facial grooves which engage balls 43 of the units 16 may replace the worm 11. Non-uniformly inclined helical grooves 36 may be used, shaped to produce intermittent or cyclically variable rotation or angular oscillation of the shaft 24. By providing for release of the reaction member 37 and locking of the bearing units 16, a two-speed gear may be produced. Several gears of different characteristics may be coupled in series to provide a multi-ratio transmission. A straight tube having internal helical grooves engaged by the outer balls of bearing units on a straight shaft coaxial with the tube has a longitudinal slot through which an elongated spur gear parallel to the tube engages the outer balls of the bearing units, so that rotation of the spur gear produces axial movement of the shaft, or vice versa. If the shaft is articulated, the tube need not be straight.</p> |
