US2040287A - Reduction gearing - Google Patents

Description

12, 1936. w. c WA 2940387 I REDUCTION GEARING Filed March 16, 1955 2 Sheets-Sheet l May 12, 1936/ WC. WARE REDUCTION GEARING Filed March 16, 1933 2 Sheets-Sheet 2 Patented ll/lay 12, 1936 i t UNITED STATES PATENT OFFICE REDUCTION GEARING Walter C. Ware, Taunton, jMass, ,assignor to Evans Stamping and Plating Company, Taunton, Mass, a corporation of Massachusetts Application March 16, 1933, Serial 'No.=661,051

6 Claims. (01. 74-413) This invention relates to reduction gearing of Fig. 2is:a:section taken along line 2--2 of Fig. l.

the internal gear type and particularly to double Fig. 3 isa sectiontaken along line 3-3 of Fig. 1. reduction gearing wherein the drive is through Fig. 4 is a section taken along line 4--4 of Fig. 1. two sets of spur and internal gears in series so Fig. 5 is a detail taken along line 5-5 of Fig.1.

5 that the driving and driven shafts are or can Fig. -6 is a sectional detail taken along line 5 'be in axial alignment. Double reduction ,gear- .66 of Fig. 5. ingsof this type are useful in marine propulsion, Figs? is a sectional detail illustrating a modiassociated with high speed engines and are in- 'fied form of end plate and driving-shaft. terposed between the usual reversing gearing Fig.8 is a plan view of thegearing involving the 10 and the propeller to reduce the high speed of. the construction of Fig. 7. 10 engine to some lower speed at which the propeller The reduction gearing illustrated. in Figs. 1

is more -efiicient. This type of reduction gearthrough 6 is intended to be supported upon the ing is not necessarily restricted tomarine proend of the casing in of the engine, the casing also pulsion, however. housing :the usual reversing gearing (not-shown) l5 Speed reducing gearing of the type involving that has a driven shaft 14 whichextends through :15 meshing internal and external gears is inherthe end of the casing and constitutes a driving ently more quiet in operation than a gearing comshaft for the reduction gearing. Thereduction posed entirely of spur gears, provided the parts gearing is provided with a front end plate 16 are properly aligned. A double reduction gearthat has a ballbearing l8 that supports the shaft;

ing of the internal gear type presents problems and said plate has a forwardly extended cylin- :20

-of design peculiar to itself, that renders it difiidrical boss or pilot '20 that is received in a corcult to'maintain the rotating parts 'in-sueh exact respondingly formed recess 22 of the end wallof alignment, when operating under full load, that the casing-so :that the plate is held in-axialalignthe :gearing can operate as noiselessly as is inment with the shaft l4. The plate is securedto 5 herently possible, and without the development the end wall of the engine casingby bolts 24, see 25 of an undue amount of heat. Figs. -1 and 6, that are screw-threaded in the end It is :an object of the present invention to prowall of the engine casing and have their heads videa gearing of this type that has its parts so located :in :recesses 26 formed in the rear face of arranged that they are held in such accurate the plate 16, see especially Figs. 5 and 6. Cor- 0 alignment that the gearing operates under responding plates 16 of otherwise identical .re-

powerat high speed with a minimum of noise and \duction gears may be differently dimensioned in heating. their engine-casing attaching means for the pur- A reduction gearing intended particularly for pose :of adapting the gearing for attachment to marine propulsion should be axially short bedifferent engine casings,'the plates I-Gthus consti- 5 cause of space limitations in the boat; and an tutingadapter plates. In Fig. '7, for instance, a,- 5 object of the present invention is an arrangement diiferent-endplate'is illustrated that converts the of the parts of the gearingwhereinit is axially gearing into a -self-contained unit, having its compact. l own driving shaft and adapted for interposition A double reduction gearing of the present type between and connection to aligned driving and 40 involves a structure having an internal gear at idriven shafts. The plate l6 forms a front cover 40 one end and a spur gear at the other end, the plate for a casing section '28 that encloses the operating forces onwhichgears tend to rock the first reduction gearing. Said casing has a cystructure in such manner as .to move the meshing -lindri cal bore or chamber 30, .the axis of which is gear teeth out of proper alignment. An object parallel but eccentric with the axisof the driven of the present invention ,is the provision of an shaft 14. The rear face of the front end plate 45 improved double reduction gearing wherein said has a rabbet or pilot 32 that is correspondingly gear structure is rotatably supported in such eccentric with the shaft l4 and is located snugly manner that it is held against displacement .of within the front end'of the-passage 30and thereits meshing gear teeth. by, in combination with the abutting radial faces A further object is generally to improve the of the end plate and casing, holds the casing in 50 construction and operation of double reduction .axial parallelism with the driving shaft. A seegearings of the internal gear type. .ond or rear casing section 34 is disposed upon the Fig. 1 is a.-sec,tion taken longitudinally through ,openrear end of the front casing section 28 and the :axis .of the gearingembodying the present has an outstanding flange 36, the radial front .55 invention. 7 face of which abuts against the corresponding and 58 for this purpose.

face of the end of the front casing section. Bolts 38 are passed through the casing sections and are screw-threaded into the front plate 16 to hold the parts rigidly in the aforesaid relation. The confronting faces of the two casing sections 28 and 34 are recessed to receive an apertured plate 48 which constitutes a pilot plate that holds the two casing sections against axial displacement and also constitues an intermediate casing or thrust plate for the first internal gear as will be presently described. Said plate 48 is secured by a pin 42 to the first casing section 28 against rotation. The rear casing section is provided with an annular chamber 44 immediately at the rear of the pilot plate 48, the axis of which chamber is parallel and concentric with the axis of the driving shaft l4. The driving shaft I4 is provided with a spur gear 46. A cylindrical drum or cylinder 48 is located within the front casing section 28 and is open at the forward end and has internal gear teeth 50 which mesh with the teeth of the spur gear, thereby providing the first reduction unit. The cylinder 48 has a radial rear end wall 52 that has a rearwardly extended boss or hub 54 that is located within the chamber 44 of. the rear casing section eccentrically therewith but concentric with the cylinder 48 and is provided with spur gear teeth 58. An annular ring or cylinder 58 is located within said chamber 44 concentrically therewith and has internal gear teeth 69 that mesh with the spur gear teeth 56, thereby constituting the second reduction gearing. The internal gear cylinder 58 has an integral radial rear end wall 62 that has a rearwardly extended stud or driven shaft 64 that is concentric with the internal gear and has a flanged driving hub 66 keyed or otherwise fixed thereto. Said hub is supported rotatably in a ball bearing 58 supported by the end wall 18 of the casing section 34 and said bearing holds the driven shaft against axial'displacement. The driven shaft 64 is thus supported concentrically with the driving shaft M. A cover plate 12 is secured to the end wall 10 of the casing and overlies the bearing 68 and has an oil packing 14 therein. The length of the gear cylinder 48 is such that it is a close running fit between the front plate l6 and the pilot plate 40. Said plates overlie the front and rear faces of said cylinder and thereby hold the cylinder against axial displacement. The cylinder is supported rotatably within the front casing 28 by roller bearings 76 and 18, the cylinder 48 compris- Iing the inner race for the rollers of both bearings and there being separate outer races 88 and 82 which are carried by the casing. A spacing ring 84 is interposed between the bearings and so restrains them from axial movement. A roller bearing 86 surrounds and engages the second gear cylinder 58 and has its outer race 88 located within the chamber 44 of the rear casing section. A lubricant can be introduced into the casing through the opening 90 at the top of the rear casing section and can circulate into contact with the moving parts therein, oil holes 92 being provided in theradial faces of the internal gears 48 A water jacket 94 surrounds the lower half of the front casing section 28 and water can circulate through the jacket between suitably disposed inlet and outlet passages 98 for the purpose of cooling the oil which may become heated due to the churning action of the moving parts thereon when such cooling is necessary. The water jacket is applied only to the lower half of the front casing section since the casing section can thus be made to appear concentric with the driving and driven shafts and thereby present a symmetrical appearance, the cooling effect being ample as thus arranged.

The bearing 16 surrounds the internal gear 48 in the radial line of its engagement with the spur gear 48. Hence said bearing directly supports the internal gear against the thrust of the spur gear. The spur gear 56 connected with said internal gear is over-hung from the bearings 16 and 18 so that the spur gear exerts a thrust on the combined structure that tends to rock it. The bearing 78, however, is disposed as close as practical to the spur gear 55 and the internal gear cylinder 48 is comparatively long so that the bearings l8 and 18 are relatively wide apart and thus provide a stable support for the structure that resists angular displacement of the structure and misalignment of the meshing gear teeth. The roller bearing is disposed in the radial line of the second internal gear 58 and hence supports said gear against the thrust of. its meshingspur gear 56. The bearings 86 and 68 are relatively widely spaced in an axial direction and hence provide a stable support for the second internal gear. By positioning the roller bearings as described the axial length of the gear is made short and the pressure on the bearings is made small. The utilization of the internal gears as the inner races for the bearings permits the diameter of the enclosing casing to be kept down and also decreases the rolling speed of the rollers. By positioning the bearings as above described, leverage on the bearings is largely eliminated so that there is little tendency for axial displacement of the internal gears. of the casing are held in axial alignment by their pilots and hence the gear teeth are caused to be maintained in alignment so that the gearing opcrates quietly and with little heating under load.

The gearing illustrated in Figs. 7 and 8 is a unitary construction having a self-contained driving shaft and adapted to be maintained in position between and connected to driving and driven shafts. For this purpose the front cover plate 16a, corresponding to the plate I B of Fig. 1, is provided with a forwardly directed hub 98 that carries axially spaced ball bearings I81; and I00 in which a driving shaft I4a is rotatably supported, the shaft having the spur gear 48 at the rear end of a driving flange I82 at the forward end. The hub 98 can be provided with oppositely directed feet I84 and the rear casing section 34a can be provided with similar feet I06 so that the reduction gearing can be mounted on suitable supports.

I claim:

1. Reduction gearing comprising the combination of a driving shaft having a spur gear, a driven shaft having an internal gear, a speed reducing unit connecting said gears comprising a cylinder having internal gear teeth at the front end thereof that mesh with the teeth of said spur gear and having a rearwardly extended reduced section having external gear teeth that mesh with the teeth of said internal gear, and an enclosing casing for said gearing comprising a front casing section that surrounds said cylinder and a rear casing section that surrounds said internal gear, and a thrust'plate interposed between said sections and overlying and engaged by the rear end of said cylinder and interposed between the confronting ends of said cylinder and said driven shaft internal gear.

2. Reduction gearing comprising the combination of a driving shaft having. a spur gear, a

The sections driven shaft having an internal gear, a speed reducing unit connecting said gears comprising a cylinder having internal gear teeth at the front end thereof that mesh with the teeth of said spur gear and having a rearwardly extended reduced section having external gear teeth that mesh with the teeth of said internal gear, and an enclosing casing. for said gearing comprising a front casing section that surrounds said cylinder and a rear casing sectionthat surrounds said internal gear, and a pilot plate interposed between and located in confronting recesses of said sections and overlying and engaged by the rear end of said cylinder and interposed between said cylinder and said driven shaft internal gear, said front casing section having a cover plate for the end thereof that overlies and engages the front end of said cylinder.

3. Reduction gearing comprising, the combination of a driving shaft having a spur gear, a driven shaft having an internalgear, a speed reducing unit connecting said gears comprising a cylinder having internal gear teeth that mesh with the gear teeth of said spur gear and a reduced rearwardly extended projection provided with gear teeth that mesh with the teeth of said internal gear, and an enclosing casing for said gearing comprising abutting front and rear casing sections, and a pilot plate interposed between and located in centering recesses of said sections, said pilot plate overlying and engaging the rear end of said cylinder and also overlying the forward end of said driven shaft internal gear.

4. Reduction gearing comprising the combination of a driving shaft having a spur gear, a driven shaft having an internal gear, a speed reducing unit connecting said gears comprising a cylinder having internal gear teeth at the front end thereof that mesh with the teeth of said spur gear and a rearwardly extended reduced portion provided with external gear teeth that mesh with the teeth of said internal gear, an enclosing casing for said gearing comprising a front casing section which surrounds said cylinder and a rear casing section that surrounds said internal gear, an anti-friction bearing carried by said front casing section and engaged with the front end of said cylinder substantially in the plane of said meshing gear teeth, a second anti-friction hearing carried by said front casing section and engaging said cylinder between the ends thereof, an anti-friction bearing carried by said rear casing. section and engaging said driven internal gear substantially in the radial plane of the gear teeth of said driven internal gear, a cover plate for the front end of said front casing section having a bearing for said spur gear and said driving shaft, and a second bearing for said driven internal gear and also for said driven shaft located in the rear end of said rear casing section and in the rear of said driven internal gear teeth, and means which hold said casing sections and said cover plate in alignment, the arrangement providing an independent bearing support for each gear element.

5. Reduction gearing comprising a driving shaft having a spur gear, a driven shaft having an internal gear, a speed reducing unit connecting said shafts comprising. a cylinder having internal gear teeth at the front end thereof that mesh with the teeth of said spur gear and external gear teeth at the rear end thereof that mesh with the teeth of said internal gear, a casing enclosing said gearing having a front and intermediate walls and an interposed thrust plate which overlie the ends of said cylinder and hold it against axial displacement, roller bearings engaged with the periphery of said cylinder, a roller bearing engaged with the periphery of said internal gear, and a ball bearing carried by said driven shaft having an inner race fixed to said shaft against axial displacement in opposite directions and an outer race carried by said casing and fixed thereto against axial displacement in opposite directions, said ball bearing constituting means that holds said internal gear and driven shaft against axial displacement.

6. Reduction gearing comprising the combination of a driving spur gear, a driven internal gear, a speed reducing. unit connecting said gears comprising a cylinder large at one end and small at the other end having internal gear teeth at the large end meshing with said spur gear and external gear teeth at the small end meshing with said internal gear, a casing enclosing the aforesaid elements comprising a front casing part that surrounds the major part of said cylinder and a rear part that surrounds said internal gear, bearing means carried by said front casing part which provides the rotatable support for said cylinder and restrains it from axial displacement, other bearing means carried by said rear casing part which provides the rotatable support for said internal gear and restrains it from axial displacement, the bearing means for said cylinder being larger in internal diameter than the external diameter of the external gear teeth of said cylinder and being otherwise arranged so that said cylinder can be withdrawn from said front casing part through the open front end thereof independently of said internal gear and the bearing means for said internal gear being such that said internal gear can be withdrawn forwardly from said rear casing part through the open front end thereof.

WALTER C. WARE.

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