GB2309056A

GB2309056A - Variable-ratio tapered-roller planet gearing

Info

Publication number: GB2309056A
Application number: GB9705784A
Authority: GB
Inventors: Eric Albert Whateley
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-01-07
Filing date: 1997-03-20
Publication date: 1997-07-16
Anticipated expiration: 2017-03-20
Also published as: GB9705784D0; GB9700203D0; GB2309056B

Abstract

An input shaft 1 drives one or more tapered rollers 3 mounted on a carrier 4. A non-rotating, axially-movable control ring 8 has plungers 10 engageable with hemispherical recesses 7 on the roller 3. The recesses are arranged in circular rows at right angles to the roller axis. The plungers 10 are moved radially against springs by fluid pressure in a chamber 11 to engage to engage the recesses 7. The fluid pressure is released during a change of ratio, to retract the plungers while the control ring 8 is moved axially into alignment with another row of recesses. The output is either from the carrier 4 or from a gear 6 engaged by a gear 5 rotating with the roller 3.

Description

MULTIPLE SPEED TRANSMISSION This invention relates to a multiple speed transmission.

Multiple speed transmissions are well known in road and off road vehicles and industrial applications. The two main types of transmission are the layshaft with a synchronizing unit for ratio changing and the automatic using epicyclic gearing and multi plate clutches. It is usual that external or internal gear teeth are ofthe involute form subjected to bending and surface fatique, during their application under load and any tooth failure can lead to high consequential damage.

According to the present invention comprising an input shaft driving one or more tapered rollers with their outside surface parallel with the input shaft axis. The tapered rollers surface have lines of hemispherical holes around its circumference. The tapered rollers are supported at its output by a carrier ring. A control ring restrained from rotation but adjustable axially with its internal surface having hemispherical protrusions which when engaged with the hemispherical holes rotate the tapered rollers in a planetary fashion. The hemispherical protrusions are held in position by pressure, for example air or liquid which when released allows the protrusions to be withdrawn allowing the control ring to move axially. The output shaft is driven alternatively by the carrier or the gear driven from the tapered rollers.

A specific embodiment of the invention will now by way of example with reference to the accompanying drawings be described Fig 1 shows a longitudinal section of the transmission Fig 2 shows an enlarged section on A.A. of the hemispherical holes and protrusions.

Referring to the drawing Fig 1 the transmission has a input 1 driving one or more gears 2 attached to tapered roller 3 supported in the output carrier 4. The end of the tapered roller 3 has gear 5 driving gear 6. The tapered roller 3 outside surface is parallel to the input shaft axis and has a series of hemispherical holes 7 around the circumference at right angles to its axis with each series of holes having identical pitch. The distance between each row dependant on the number of hemispherical holes in each row.

Around the outside of the tapered roller 3 is a control ring 8 and inner ring 9 joined together but restrained from rotation by a number of shafts 14 but able to slide axially. Fig 2 has the enlarged section A.A and shows the control ring 8 and inner ring 9 has a number of plungers 10 with a lip and hemispherical end retained in position for example by air or liquid pressure in sealed cavity 11 with springs 12 retracting the plunger 10 when the pressure is released.

Referring to Fig 1, in operation the input shaft 1 rotates the taper roller 3 with the hemispherical holes 7 engaging with the stationary hemispherical ends of plunger 10 and rotates with the carrier 4 and gear 5 in a planetary fashion. The carrier 4 is attached not shown to the output shaft 13 with the gear 6 free to rotate. When a change in ratio is required the pressure in cavity 11 is released allowing the plunger 10 to retract and the control ring 8 and 9 to move axially to the next line of hemispherical holes. This operation will proceed until it reaches the large end of the tapered roller 3 at which point the output speed of the carrier 4 approximating to one third of the input speed.

Gear 6 driven from gear 5 through an idler gear not shown rotates at the same speed as the carrier 4 but in the opposite direction. Gear 6 can be attached to the output shaft 13 through a reverse gear layshaft assembly not shown to give the same direction of rotation and speed as the carrier 4 which is then disengaged.

The controlling 8 and 9 can now move axially towards the small end of the tapered roller 3 increasing the output shaft 13 speed from approximately one third to approaching input speed.

Claims

1. An input shaft driving one or more tapered rollers whose outside surface has a series of holes of equal pitch around its circumference at right angles to its axis and encircled by a control ring with its inner surface having protrusions.

2. A control ring as in Claim 1 wherein the protrusions held in position by pressure are able to engage with the holes in the tapered rollers.

3. A control ring as in Claim 1 or 2 restrained from rotation but able to slide axially encircles the tapered rollers.

4. A control ring as in Claim 2 or 3 wherein the protrusions are retracted by releasing the pressure and allowing axially sliding.

5. One or more tapered rollers as in Claim 1 supported in a carrier and the tapered rollers driving a gear enables either the carrier or gear to drive the output shaft from the planetary assembly.