tailieunhanh - The Motor Vehicle 2010 Part 12

Tham khảo tài liệu 'the motor vehicle 2010 part 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Epicyclic and pre-selector gearboxes 795 than the rotating sun wheel the situation is similar but P becomes the fulcrum so although the planet carrier still rotates anti-clockwise the sun wheel S1 rotates in the opposite direction. Although there are many other forms of planetary gearing the two described here are those most commonly used in automotive applications. The broad principles already explained apply to them all. Heavy duty epicyclic gearing is to be found mostly in pre-selector and automatic gearboxes and back axle differentials. In the latter bevel type planetary gears are usually used for turning the drive through 90 they have also the advantage of compactness. Examples of bevel gear types are illustrated in Chapters 31 33 and 34 the clearest being Fig. . As is explained in those chapters the terminology for differentials is different the planets are housed in a carrier called the differential cage bolted to the crown wheel. The latter in effect is substituted for the annulus. There are two sun wheels termed differential gears one on the inner end of each halfshaft. These mesh with the planet or differential pinions. Epicyclic gear ratios For ease of recognition of the various gears in all that follows the annulus gear is called A the planet carrier C the sun gear S and the planet gear P and it is assumed that the gears have respectively A S and P teeth. If either end of the planet carrier arm is integral with a tubular shaft and coaxial with the gear shaft at that end the arm can be used as either the input or output. First take the case of the planet being fixed and the carrier arm serving as the input turned through one revolution clockwise about the axis of S Fig. a . If the wheel S were not in mesh with P and were fixed to the planet arm it too would have been orbited through 360 . However since it is in mesh with P it will also have rotated P S times about its own axis so its total rotation will be 1 P S revolutions. Therefore the .