US1993051A - Frictional epicyclic gearing - Google Patents

Description

March 5, 1935. c. DELL Er AL FRICTIONAL EPICYCLIC GEARING Filed Jan. 3l, 1934 J 2 50,7%; ,ff

Patented Mar. 5, 1935V UNITED srirri-ssv PATENT o -fFFlc-E FRICTIONAL EPICYCLIC iGEARING Cyril Dell, Berkhamsted, and Herbert Louis Read,f

Hutton Mount,

England, assignors to Dellread Gears (Holdings) Company Limited, London,

England Application In Great Britain 6 Claims;

This invention relates to frictional epicyclic gears and has for its object to -improve and simplify the construction of devices of this type in general and to provide improved and simple i means for effecting the contact pressure between By this the various members of the gear.

According to this invention a gear of the type indicated, i. e. comprising aV sun member, a series of planets mounted on Aa Ycarrier and-an annulus is characterized in that the sun and the :planets are locked against 'relative axial move- .ment Aand are bodily movable in axial direction for pressure adjustment relatively to the-'annulus which has a conical or curved contact surface. means independent pressure on the planets axially is avoided, and the liability to excessive strain` and distortion on the planet axles `and their bearings is Vobviated.

In one embodiment the arrangement is such4 vthat .the sun andthe planets become interlocked Y when assembled, no separate members to effect -the interlocking being required. For this purpose the sun Yandthe planet carrier may abut and the lsun and planets may be made frusto conical with A'the imaginary apex of the sun on the side op- Lposite .to the planet carrier. The sun is thereby wedged between the planets and cannot be moved relatively thereto in the direction of its apex, `whilst its movement in the opposite direction is prevented by its abutment against the planet carrier. Or, the contacting surfaces ofthe sun and the planets may be curved thereby eifectfing the. interlocking of these members against the'axial separating movement. VIf thesun and :the planets are not so formed as to effect interlocking .against axial separation when these members are assembled thenseparate fastening .or interlocking devices may be added to effect this interlock. 1

YOther features of the frictional epicyclic gear` u or may not be rotatable and is held together by January 31, 1934, serial No. 709,218

February 21, 1933 (Cl. 'i4-302) means of screws 4. The parts 2 and 3 of the casing have bosses 5 and 6 respectively. Inithe boss 5 runs the input shaft 7 on ball bea rings 8 and 9 and the output shaft vl0 is similarly mounted in boss 6 on ball bearings 11 and 12'. In

the vexample shown the sun 13 is integral the input shaft 7 and the carrier with 14 of planets 15 is integral with the output shaft 10. The annulus 1, the sun 13 and the planets 15 have conical Contact surfaces and the sun13` and planet 'carrier 14 abut, the imaginary apex 16 of the sun 13 being on the sideaway from the planet Vcarrier 14. Therefore, when the device is as Sembled axial movement of Vthe sun- 131relatively to the planets 15 in the direction of its apex'is vented because in wedged between the planets.

In theopposite direction against the planet carrier 14 under Ythe -inter ment insthat direction is prevented.

Y pre- 'that` direction the sun is the sun 13 abuts position of a thrust bearing '17 and thereby its move- It will be obvious that any axialpressure applied to the planet carrier 14, as fork examp le by the movement of the adjustingring 19vial the bearing 11 on to the shoulder ofthe Vshaft 10',

will be transmitted solidly to the shaft 7 thr the bearing 17 on to the shoulder of the sun 13 against which it bears.

There can therefore be ino possible axial movement relatively between parts of the assembly revolving inside the a lus and its casing.

nnu-

Ihe sun 13 and the lplanets 15 are thus interlocked against axial separation when assembled andY they can only be moved bodily in relation to the annulus 1 to effect contact pressure adjustment between theiatterland the planets. As

is well known the correctness of such adjustment is Vof great importance for Athe satisfactory operation of the gearv as the reduction of slipto the wasteful and harmfulV heating up and the possible minimum and thereby elimination of load ' transmitting capacity of the gear depend on the correctness of this adjustment. It has been found-that if the pressure adjustment between the sun and the planets is correctly effected when assembling these parts no subsequent adjustment is required between these parts, so that eventual adjustments are conned to that between the planets and the annulus and this, as already Y mentioned, is effected (in the Vexample shown) by bodily moving the interlocked planets and sun relatively to the annulus.

The axial displacement of :the interlocked planets and` sun is effected between very limits by an externally threaded ring 18 scr fine.

ewed

into the boss 5 and the aforesaid similar ring 19 screwed into the boss 6. These two rings are screwed up tightly on both sides after adjustment has been effected and according to whether reduction or increase of pressure is required between the planets 15 and the annulus 1 one ring is eased and the other tightened up. For pressure reduction, ring 19 is eased and ring 18 tightened up, and for pressure increase, ring 18 is eased and ring 19 tightened up.

For assembling the sun and the planets the sun is caused to abut against the planet carrier 14 under the interposition of thrust bearing 17 and the planet axles 20 are located in theirrespective slots 21 provided in the periphery of the planet carrier 14 (see also Figure 6). A distance ring 22 is placed between the planets 15 and the carrier 14, the planet axles 20 being secured in position by means of nuts 23 screwed on their threaded rear end under the interposition of locking washers 24 which prevent subsequent turning or unscrevving of the nuts. The planets, when mounted, are caused to abut radially against the sun 13 with the required or correct driving pressure.

Preferably, as shown in Figure 6, between the planet axle slots 2l further radial slots 25 are made in the periphery of the planet carrier 14, so as to form slightly resilient prongs between which theV planet axles 20 are received, the resilient flexibilityof the carrier V14 enabling the planets to seat themselves with uniform pressure on the sun, and to run with a perfect circumferential balance, i. e. with equal pressure on the annulus and sun at all pointsA of the track. The slots 25 are preferably narrower and deeper than the slots 21. f

In Figures 2, 3 and 4 alternative methods of providing interlocking between the planets 15 and the Vsun 13 are shown. InFigure 2 the sun 13 and the planets i5 have curved contact surfaces so that they arey interlocked against relative axial movement when assembled, and the annulus l has a conical contact surface. In Fig- *f ure 3 the arrangement is similar, but the annulus 1 has aY convex contact surface. In Figure 4 the planets 15A are balls and the contact surface of thc sun 13 is suitably curved, the Contact surface of the annulus l being conical, although obviously itv could be curved as in Figure 3.

In Figure 5 the planets l5 and sun 13 are frustoconical but as distinct from Figure 1 the imaginary apices are located on the side of the system facing the planetary carrier member 14; normally, therefore, when sun and planetshare assembled and before inserting this assembly in the casing, they would be .able to separate axially. This is prevented by the rings 26 and 27 screwed on to the sun member and planet carrier respectively. Y V

The invention is not limited tothe details hereinbefore described. Thus, the sunrlS and the planet carrier 14 need not be integral with the shafts 7 and 10 respectively but may be attached thereto in any suitable manuel'. The l can be the output shaft and the shaft can be the input shaft, in which case a multiplying gear is obtained. The interlocked planets and sun may be secured against axial movement in the casing and the annulus 1 may be constructed so as to Ytoward a common axial point along the shaft kplanet gears thereon to provide flexible tongues be relatively movable to said interlooked members.

We claim:-

l. An epicyclic gear comprising a driving shaft, a driven shaft axially alined therewith, a combined journal and end thrust bearing between the inner ends of said shafts holding them inl solidly abutting relationship against endwise movement toward each other, a tapered sun gear fixed to one of said shafts, a carrier fixed with respect to the other of said shafts, a series of tapered planet gears carried by said carrier and disposed around and cooperating with said sun gear, a casing in which the solidly abutting driving and driven shafts are journaled for unitary endwise adjustments, a tapered annulus carried by said casing and surrounding said planet gears and cooperating therewith, and means for holding said shafts against relative endwise outward movement and for imparting endwise adjustments to said shafts relative to said casing to vary the pressure between the planet gears and the sun gear and annulus.v

2. An epicyclic gear comprising a driving shaft, a driven shaft axially alined therewith, an end thrust bearing between the inner ends of said shafts holding them against endwise movement toward each other, a tapered sun gear xed with respect to one of said shafts, a carrier fixed with respect tothe other of said shafts, a series of tapered planetgears carried by said carrier and disposed around-and cooperating with said sun gear, a casing in which the solidly abutting driving and driven shafts are journaled for endwise adjustments, a tapered annulus carried by said casing Yand surrounding said planet gears and cooperating therewith, said sun gearand said annulus and said planet gears all being tapered carrying the sun gear, which point is spaced from the inner end of said shaft, whereby the shafts and the sun and planet gears are interloclced for unitary endwise adjustments and whereby-such unitary endwise adjustments cause the planet wheels to cooperate with the annulus to vary the pressure between the planet gears and the sun gear and annulus, the shafts being shouldered, and members threaded in said casing and cooperating with the shoulders of said shafts tokadjust them axially to vary the pressure between the planet wheels and the sun gear and annulus.

3. An epicyclic gear as set forth in claim 1 in which the carrier is in the form of a disk radially slitted between the points of mounting of the supporting the planet gears.Y

4. vAn epicyclic gear as set forth in claim 2 in which the carrier is in the form of a disk radially -slitted between the points of mounting of the planet gears thereon to provide flexible tongues supporting the planet gears.

5. An epicyclic gear as set forth in claim 1 in which the carrier has flexible portions on which the planet gears are mounted. 6. An epicyclic gear as set forth in claim 2 in which the carrier has ilexible portions on which the planet gears are mounted.

Y C. DELL.

H. L. READ.

Images