| 摘要 |
A rack and pinion gear and a method of assembling such a gear. The gear has a rack bar 1 the rack 4 of which is biased into engagement with the pinion 6 by a spring loaded support 7 which slidably (or rolling) engages a bearing surface 8 of the rack bar. The bearing surface has a central region 9 parallel to the rack axis and tapering end regions 10 and 11 which reduce the thickness of the rack bar from the central region 9. The length C of the region 9 corresponds to 1 to 1.5 revolutions of the pinion 6 while the operative length A of the rack corresponds to at least three revolutions of the pinion. The pinion rotates about an eccentric axis 14 which varies the rack bar tightness. To determine the position of maximum tightness in which the spring loading of the support 7 is to be adjusted, the pinion is rotated from a central position on the rack 4 clockwise and counter-clockwise to displace the rack bar in each instance through a distance corresponding to 0.5 revolutions of the pinion from the said central position. During this displacement the reaction on the support 7 is observed to determine the position in which the maximum tightness of the rack bar is encountered where the spring loading of the support means is finally set. The invention is applicable to supports 7 which engage the rack bar in one or more positions around the support surface.
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