USRE22718E - Planetary transmission - Google Patents

Description

Feb- 12, 1946 H. E.'CARNAGUA PLNETARY TRANSMISSION Original Filed Aug. 25. 1941 f-WM @Mg Reued Feb. 12, 1946 PLANETARY TRANSMISSIGN Harold E. Carnagua, Muncie, Ind.,A assigner to Borg-Warner Corporation, Chicago, Ill., a corporation of Illinois Original No. 2,311,209, dated AFebruary 16, 1943,

Serial No. 408,171, August 25, 1941. Application for reissue August 22, 1945, Serial No.

8 Claims.

This invention relates to power transmitting devices of the planetary gear type and particularly to such a transmission which is adapted to provide a plurality of forward driving speed ratios including an overdrive ratio.

The present day internal combustion engines of the type and proportion generally used in an automobile require the use of a variable speed transmission between the engine and Wheels in order to satisfy generally accepted performance requirements. Such a transmission, however. if

satisfactory as to speed ratios is apt to be bulky and difficult to manipulate.- To reduce thesize of such a transmission it has been proposed to take advantage of certain inherent characteristics ofi the planetary type of gearing whereby but one planetary gear set will be sulcient to provide a reverse ratio, a neutral, a direct drive and an overdrive. The simplicity of gearing thereby 0btained is somewhat detracted from, however, by the resulting complexity of the controls necessary to bring about the ratio changes.

The principal objectof this invention is to provide a multiple ratio single planetary transmission wherein the controls are improved and simplified so as to render the transmission less expensive to build and maintain.

Another obiect'of this invention is to provide a transmission wherein a manually operated direct drive is secured and an automatic shift is made between direct and an overdrive ratio, the shift employing hydraulically controlled means.

'I'hese and other objects and features of the invention will become apparent from the following description when taken together with the accomllnyin drawing in which:

Fig. 1 is a side elevation in section of the improved transmission; and

Fig. 2 is a fragmentary elevation taken along lines 2-2 of Fig. 1, showing in detail the form of one of the coupling means.

Referring now to the drawing vfor a detailed description of the invention, I is a drive shaft which is adapted to be connected to a prime mover such as the internal combustion engine of an automobile or to the output of an axillary transmission. The driven shaft isv shown at II and is adapted to be connected to a load such as the rear wheels of an automobile (not shown) Between drive shaft Ill and driven shaft II is a planetary gear set I2 which is adapted to be connected to .the shafts by means hereinafter to be described to produce a reverse drive, a neutral, a direct drive and an overdrive. Said planetary gear set is com,- Drlsed of one or more planet gears I3 meshing Cl. 'I4-260) With a ring gear I4 formed on the interior of a drum I5, and with 'a sun gear I6 formed on the exterior of a sleeve I1. Said planet gears are mounted on a carrier I8 with which is rotatable a large drum I9 anda smaller drum 2li, drum I9 extending to the right of carrier I8 as viewed in Fig. 1 and drurn20 extending to the left. Drum` I9 is xed axially with respect to carrier I8 by means of a shoulder 2| on one side and a ring 22 on the other side. Similarly drum 2t is fixed axially with respect to carrier I9 by means of a shoulder 23 on one side and a snap ring 24 on the other side of carrier I8. Both drums I9 and 2l) are attached to and rotate with carrier I9.

'I'he right hand end (Fig. 1) of ring gear drum I5 is provided with splines 25 with which are drivingly connected a belled portion 26 of driven shaft II andaninternally toothed clutch element 21. It is apparent that ring gear I4 and clutch element 21 are constrainedvto rotate with driven shaft II at all times.

The right hand end (Fig. l) -of drum I9 is provided with clutch teeth 28 which are of the same size as internal clutch teeth 29 on clutch element 21. A washer 3l) spaces the two clutch teeth and prevents excessive axial movement between ring gear I4 and planetary gears I3.

Smaller drum 20 is provided with external n splines 3i which mesh with a slidable sleeve 32 which is likewise provided with external teeth or splines 33. Said sleeve' 32 is adapted to slide axially along splines 3| to assume a plurality of positions. In the extreme left hand position, teeth 33 engage with teeth 34 on a plate 35 which is bolted or otherwise non-rotatably secured to the casing 36 of the transmission. When so engaged, y

sleeve 32, its associated `drum member 20 and carrier I6 are all held against rotation, thereby making possible a reverse drive through planetary gear set I2.

Loosely mounted on drive shaft III and within belled portion 26 of drivenv shaft I I is a hub member 31 having external teeth 39 formed on one end thereof and a series of cams 39 formed on the'other end. .Between cams 39 and the inner surface of belled portion 26 are located rollers` 4l which constitutev a one-way or free-wheeling drive between hub member 31 and driven shaft I I.

Immediately adjacent hub member 31 is a collar 4I which is splined to drive shaft III so as to be rotatable therewith. Said collar 4I has ex' Aternal splines or teeth 42 on which is mounted an.

internally splined sleeve 43, said sleeve 43 being axially slidable rela-tive to collar 4I. Said sleeve 43 is connected to sleeve 32 by means of a pluoverdrive operation by .of piston 53 is formed into a tooth ybores 52 and 58 and direction to withdraw rod 58 and its associated ondisc 49. A

` and sleeve 43 are constrained to move together.

'I'he connection between pins 44 and sleeve 43 is such as to permit relative rotation therebetween so that if sleeve 32Ais in its extreme left hand position wherein it is held against rotation, sleeve 43 may be rotated by the drive shaft.

Sun gearv sleeve |1 is provided at one end with a toothed clutch element 45 which is adapted to be engaged by the internal teeth of sleeve 43 when the latter is moved to its extreme left hand position. It will be apparent now that in this position sun gear I5 will be driven by the drive shaft through sleeve 43, and carrier I8 will be held against rotation, thereby causing ring gear 4 to be driven reverselyand with it the driven shaft Ii. Sleeve 43 is also provided with external teeth 48 which are adapted to engage teeth 28 and 29 on drum I9 and clutch element 21, respectively. When engaged with either of these teeth. the internal splines likewise engage teeth 38 on hub member 31 and thereby transmit drive simultaneously to this member.

When teeth 46 engage teeth 28, drum I3 and hub member 31 are both driven by the drive shaft and, depending upon whether or not sun gear I8 is held against rotation, the transmission will be either in direct drive or in overdrive. direct drive being secured through the free-wheel connection established between cams 39, roller 48 and belle'd portion 25 oi' driven shaft I When sleeve 43 is in its extreme right hand position so that teeth 48 engage teeth .23 and do not engage teeth 28, said sleeve 43 provides a direct connection between belled portion 25 and drive shaft I8 so as to lock out the free wheeling action of rollers 40. In this position direct drive only will be obtainab The position of sleeve 32 and sleeve 43 is de-v termined by means of a manually controlled disc 41 which is secured to sleeve 32.

'I'he transmission illustrated is designed to produce an overdrive automatically through the planetary gear set. The latter is conditioned for arresting sun gear |8 and coupling teeth 45 on sleeve 43 with teeth 28 on drum I9. The means by which sun gear Il is held against rotation will now be described.

It will be observed that on the left hand end (Fig. l) of sleeve I1 are formed external teeth or splines 48. An internally toothed disc 43 meshes with splines 48 to cause said disc to rotate with sleeve I1 and sun gear I6. Around the outer periphery of disc 49 are teeth 50 as shown in Fig. 2, the teeth having sloping or cammed outer surfaces 5|. Located within housing 38 is a bore 52 within which is reciprocable a piston 53. The outer end 54 resembling a pawl the outer surface 55 of which is also sloped or cammed. The inside of piston 53 is formed into a rod 55 which passes through a second piston 51 located ina larger bore 58. 'I'he is threaded to receive a nut 88 abutment for piston against the shoulder end 59 of rod 58 which forms an 51. A coil spring 8| reacts s2 formed by the Junctio of urges piston 51 outward in a piston 53 and pawl 54 from contact with teeth 50 second coil spring 53 is designed specically to'take up the lost motion connection between pistons 53 and 51 by tending to'separate the pistons.

'I'hus when duid under pressure is admitted behind piston 51 the pressure will be transmitted tion between teeth h piston 53 which in turn will be urged toward disc 43 to engage pawl 54 with teeth 5|). Ii' at the moment there is relative rotaand pawl 54, engagement through spring 83 to will be precluded surfaces 5| and 55 against one another. The pressure of the duid will be absorbed in spring 83 so that piston 51 may assume its fully engaged position and remain in such position independently of the movement of piston 53. At the instant when relative rotation between the disc and pawl ceases and slightly reverses its direction. pawl 54 will engage teeth 58 and thus arrest the rotation of sun gear I5.

The automatic control for the iluid pressure will now be described. 'I'he iluid circuit includes a conduit I4, leading to -a sump or other reservoir of iiuid such as oil, which conducts the fluid to a suitable power driven pump and thence to a conduit 85 formed in a rotatable valve block 81 which is trunnioned in casing 38 at 88 and 88. The pressure' within conduit 88 is regulated `by means of a suitable pressure relief valve 1li.. Valve block 51 is connected by means of gears 1| and 12 to driven shaft il so as to be rotatable in response to the rotation of said driven shaft. With,

in valve block 81 is a radial bore 13 in which is mounted a valve 14. Said valve has a circumferential groove 15 in communication with a central vent groove 18.. and a relatively wide circumferential groove 11 located adjacent groove 15. `A spring 18 acting against a washer 19 and a bolt 88 threaded to valve 14 biases said valve'radially ihwardly. It will be noted that the bulk of the valve is eccentric to the axis of rotation and that this eccentricity will tend to increase as the valve is rotated. The spring thus counteracts the centrifugal force developedin the rotating valve and it may be adjusted to provide any suitable initial tension. A conduit 8| invalve block 81 is so located with respect to conduit 55 and circumferential grooves 15 and 11 that when the valve is in the position shown, that is, the position assumed when it is not rotating, conduit 8| will be vented through groove 15 and conduit 18, and at the same time-conduit 65 will be blocked olf. When the valve is rotated at some predetermined speed, say for example a vehicle speed of 23 miles per hour, it will assume a position such that circumferential groove 11 will connect conduit 88 with conduit 8| andk admit fluid pressure past the valve.

Conduit 5| connects with conduits 82 and 83' in casing 86 which ultimately connects with bore 58.

It will be evident from the foregoing description that when control disc 41 is in its rst left.

with it is rotated valve 14. Up to the predetermined speed for which the valve is set, conduit 8| will be vented through the valve and there will be no pressure behind the piston 58. At or above the predetermined speed, valve 14 will be in lits radially outward position wherein iiuid under pressure is admitted behind piston 51 to force it inwardly together with pawl 54. The

bythe camming action oi' the sun gear will not be immediately arrested. however, since the camming action of the pawl and teeth 50 will prevent such engagement. To engage the pawl with the teeth. torque on drive shaft III is momentarily released as by slowing down the prime mover in order to slow down this shaft with respect to the driven shaft, the latter rotating at substantially the same speed due to the momentum of the load associated therewith. The slowing down of drive shaft il causes disc I! to .slow down and eventually to come to a standstill and then begin to rotate in the reverse direction. When this occurs the disc will be rotated Just far enough to permit pawl III to become aligned with a slot or space between teeth and it will then engage the teeth and hold the sun gear against rotation. During this time the driven shaft has been free-wheeling with respect to the drive shaft. `When the sun gear is arrested, the drive then becomes an overdrive and will obtain as long as fluid pressure is present behind piston I1.

It is to be understood that the foregoing description is merely illustrative of the preferred embodiment of the invention and that the scope of the invention therefore is not to be limited thereto but is to be determined by the appended claims.

I claim:

1. A transmission comprising drive and driven shafts; planetary gearing. including a sun gear connectible between the shafts to establish reverse, direct and overdrive ratios; a source of fluid under pressure; a centrifugaily operable valve driven from the driven shaft; a positive brake for arresting the rotation of the sun gear of the planetary gearing to'establish overdrive; hydraulic means for operating the brake, said hydraulic means comprising a fixed housing having a bore therein, a step in the bore, a piston in the wider portion of the bore, a second piston in the narrower portion of the bore, a lost motion connection betwee'n the pistons, resilient means between the step and one ofthe pistons for urging the said one of the pistons in a direction to take up the lost motion connection, and resilient means for transmitting the pressure from .one piston to the other; and conduits connecting the source of fluid under pressure, the valve and the hydraulic means, said valve being adjusted to admit fluid under pressure to the hydraulic means at a predetermined speed of the driven shaft to establish overdrive.

2. A transmission comprising drive and driven shafts; planetary gearing, including a sun gear connectible between the shafts to establish reverse, direct and overdrive ratios; a source of fluid under pressure; a centrifugally operable valve driven from the driven shaft; a positive brake for arresting the rotation of the sun gear of the planetary gearing to establish overdrive; hydraulic means for operating the brake, said hydraulic means comprising a nxed housing having a bore therein, a step in the bore, a piston in the 'wider portion of the bore, a second piston in the narrower portion of the bore, a lost motion connection between the pistons, resilient means be tween the step and one of the pistons for urging the said one of the pistons in a direction to take up the lost motion connection, and resilient means for transmitting the pressure from one piston to the other; ,the' brake comprising a wheel on the sim gear, said wheel having slots, and a paw] on one of the pistons engageable with the slotted wheel to arrest the rotation of the 'sun gear; and

conduits connecting the source of uuid under Pressure, the valve and the hydraulic means, said valve being adjusted to admit fluid under` presunderpressure; a positive brake for arresting therotation of the sun gear of the planetary gearing to establish overdrive; hydraulic means for operating the brake; a centrifugaliy operable valve driven from the driven shaft; and conduits connecting the source of fluid under pressure, the valve, and the hydraulic means; said valve comprising a rotatable block, a radially disposed valve inthe block, and resilient means for urging the valve radially inwardly, said valve having a circumferential groove in communication with a vent opening, and a second circumferential groove. said second groove being connected only with the conduit to the source of fluid under pressure when the valve is rotated below a predetermined speed, and the second groove connecting the source of fluid under pressure and the'hydraulic means conduits when"the valve is rotated above a predetermined speed: said valve being adjusted to admit fluid under pressure to the hydraulc means at a predetermined speed of the driven lshaft to establish overdrive.

4. A transmission comprising drive and driven shafts, planetary gearing connectible between the shafts. and control means for the planetary gearing adapted to establish la' plurality of speed ratios through said planetary gearing, said control means comprising an element loosely mountwheel drive, and in a third position connecting ed on the drive shaft, a siidable sleeve mounted for rotation with the drive shaft, an overrunning clutch between the element and driven shaft, and cooperable clutch means on the sleeve and driven shaft, said sleeve in a first position being disconnected from the element and driven shaft, in a second position connecting vthe element with the drive shaft to establish a free the shafts together for a two-way drive.

5. 4A transmission comprising drive and driven A shafts, planetary gearing connectible between the shafts' to establish a plurality of speed ratios, said planetary gearing including a planet gear lcarrier, a splined drum rotatable'with the carrier, a positive brake for the carrier comprising a fixed element and an axially 'slidable element adapted to engage the fixed element, said axially slidable element being mounted to rotate withy the drum, an element loosely mounted on the drive shaft, a slidable sleeve mounted for rotation with the drive shaft, an overrunning clutch between the loosely mounted element and driven shaft, and cooperable clutch means on the sleeve, loosely mounted element and driven shaft, said sleeve in a first position being disconnected from the loosely mounted element and driven shaft to establish neutral. in a second position connesting the loosely mounted element with the drive shaft to establish a free-wheel direct drive, and in a third position connecting the shafts together for a positive two-way drive, and means connecting the slidable sleeve on the drive shaft with the slidable brake element on the carrier `drumtocausethetwotomoveinunisomsaid connecting means preventing the engagement of the brake elements when the slidable sleeve is in neutral, free-wheel drive positions. Y

6. A transmission as described in claim 5, said carrier havinga second drum rotatable therewith and extending in the direction of the driven shaft, said drum'having clutch means cooperablevwith the clutch means on the slidable sleeve rotatable with the drive shaft and eil'ectivevto couple the drive shaft with the carrier to condition the transmission for overdrive.

'1. A transmission comprising drive and driven shafts, planetary gearing connectible between the shafts to establish a plurality of s peed ratios, said gearing comprising a ring gear, a sun gear and a planet gear carrier, a sleeve surrounding the drive shaft and rotatable with the sun gear, a brake element on one end of the sun gear sleeve, a clutch element on the other end of the sleeve, a drum on the carrier, means spacing the drum from the brake element, means preventing axial movement between the carrier and drum, a second drum on the carrier and extending in the opposite direction from that of the first drum, means on the second drum preventing relative movement between the drum and carrier in the direction of the brake element, a clutch element on the driven shaft in proximity to a clutch element on the second drum, spacing means between the two elements, said spacing means limiting the movement of the second drum and associated carrier and rst drum in the direction of the driven shaft, an element freely rotatable on the drive shaft, an overrunning clutch between said rotatable element and the driven shaft', a collar splined to the drive shaft, a slidable sleeve on the collar rotatable with the collar and having a clutch element cooperable with the clutch element on the second drum and with the element on the driven shaft, means for connecting the slidable sleeve with the clutch element on Y the sun gear sleeve so as to drive the latter from the drive shaft, a second brake element, a slid- 'able sleeve on the rst carrier drum engageable with the second brake element to arrest the rotation of the carrier, and means connecting the last mentioned slidable sleevey and the slidable sleeve on the drive shaft collar so as to Icause the two to move in unison, said connecting means shaft and adapted inone position to connect the direct, or positive direct in one position connecting the sun gear to the drive shaft and the carrier to the second brake element, in a second position disconnecting the drive shaft from the sun gear and the second brake element from the carrier to provide a neutral, in a third position connecting said rotatable element and the clutch element on the second drum to the drive shaft to provide a free-wheeling direct drive, and in a fourth position connecting the drive and driven shafts directly together.

8. A transmission comprising drive anddriven shafts, planetary gearing connectible between the shafts and comprising a ring gear, a sun gear and planet pinions meshing with the ring and sun gears, a carrier for the planet gears, a freely rotatable collar on the drive shaft, an overrunning clutch between the collar and driven shaft,

'axially fixed clutch means on the collar. the sun gear, the carrier and on the driven shaft, axially slidable clutch means connected with the drive drive shaft to the sun gear, in another position to the carrier and collar, and in a third position to the driven shaft and collar, a slotted brake member on the sun'gear, a radially movable pawl adaptedv to engage the slotted brake member to arrest the rotation of the sun gear, piston means for effecting radial movement of the pawl to engaged and disengaged positions, a hydraulic circuit including a source of uid under pressure and conduits for conducting the iluid under pressure to the piston means, a. centrifugally operable valve inthe hydraulic circuit adapted in one position to vent thefiuid behind the piston means and in another position to admit duid under pressure therebehind, a gear drive between the driven shaft and valve for driving the valve in response to rotation of the driven

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