Planetary gearset

Abstract

The invention concerns an epicycloidal gear train (10) comprising a central pinion (26), an outer crown (28) and satellite pinions (32) in engagement with the central pinion (26) and the outer crown (28) and each mounted freely rotatable on a satellite carrier (36), the gear train (10) comprising an annular cup (56) being integral with the satellite carrier (36) and open radially inward. According to the invention, the cup (56) is divided into a circumferential succession of first basins (60) of the first oil circuit and second basins (62) of the second oil circuit, the first basins (60) being fluidly separated from the second cells (62) and characterised in that the cup (56) comprises two annular walls (56a, 56b) axially facing, the annular wall (56b) of which is furthest from a median transverse plane (74) of the gear train (10) has openings (76) opening into the second basins (62).

Claims

1. An epicycloidal gear train comprising a central pinion, an outer crown and satellite pinions engaging the central pinion and the outer crown and each mounted freely rotatable on a satellite carrier, the gear train comprising a first lubrication oil circuit for contact areas of the gear teeth of the satellite pinions with the central pinion and a second lubrication oil circuit for axes of the satellite pinions, an annular cup being integral with the satellite carrier and open radially inward, characterized in that the cup is divided into a circumferential succession of first basins of the first oil circuit and second basins of the second oil circuit, the first basins (60) being fluidly separated from the second basins and in that the cup comprises a first and a second annular wall axially facing, said first annular wall being further from a median radial plane of the gear train than said second annular wall, said first annular wall having openings opening into the second basins.

2. A gear train according to claim 1, characterized in that the openings comprise notches delimiting a portion of a radially inner annular edge of said first annular wall so that said annular edge includes notches.

3. A gear train according to claim 2, characterized in that the notches extend over an entire angular distance of one of said second basins.

4. A gear train according to claim 1, characterized in that the first basins are connected to first oil supply lines of said contact areas between said teeth of the satellite pinions and said teeth of the central pinion, and in that the second basins are connected to second oil supply lines of the axes of the satellite pinions.

5. A gear train according to claim 2, characterized in that the first basins are connected to first oil supply lines of said contact areas between said teeth of the satellite pinions and said teeth of the central pinion, and in that the second basins are connected to second oil supply lines of the axes of the satellite pinions.

6. A gear train according to claim 3, characterized in that the first basins are connected to first oil supply lines of said contact areas between said teeth of the satellite pinions and said teeth of the central pinion, and in that the second basins are connected to second oil supply lines of the axes of the satellite pinions.

7. A turbomachine comprising a gear train according to claim 1, the central pinion of which surrounds and is rotationally fixed to a shaft of the turbomachine, and first oil spraying means arranged radially outside the shaft and having at least one oil nozzle projecting oil towards the annular cup.

8. A turbomachine comprising a gear train according to claim 2, the central pinion of which surrounds and is rotationally fixed to a shaft of the turbomachine, and first oil spraying means arranged radially outside the shaft and having at least one oil nozzle projecting oil towards the annular cup.

9. A turbomachine comprising a gear train according to claim 3, the central pinion of which surrounds and is rotationally fixed to a shaft of the turbomachine, and first oil spraying means arranged radially outside the shaft and having at least one oil nozzle projecting oil towards the annular cup.

10. A turbomachine comprising a gear train according to claim 4, the central pinion of which surrounds and is rotationally fixed to a shaft of the turbomachine, and first oil spraying means arranged radially outside the shaft and having at least one oil nozzle projecting oil towards the annular cup.

11. Turbomachine according to claim 7, characterized in that said at least one nozzle is carried by an outer surface of the shaft and positioned so that its oil jet is directed towards the cup.

12. Turbomachine according to claim 7, characterized in that the gear train is a reducer and is mounted in an annular chamber formed radially inside a low-pressure compressor, the satellite carrier being connected to an upstream fan wheel and the shaft being a shaft of the low-pressure compressor.

13. Turbomachine according to claim 11, characterized in that the gear train is a reducer and is mounted in an annular chamber formed radially inside a low-pressure compressor, the satellite carrier being connected to an upstream fan wheel and the shaft being a shaft of the low-pressure compressor.

14. Turbomachine according to claim 12, characterized in that the gear train reducer is axially interposed between an upstream bearing and a downstream bearing supported by a stator structure of the low-pressure compressor, the upstream bearing rotatably guiding a connecting shaft (38) from the fan wheel to the satellite carrier and the downstream bearing rotatably guiding the shaft of the low-pressure compressor.

15. Turbomachine according to claim 14, characterized in that the first oil spraying means are fixed and are integrated into an oil circuit further comprising second oil spraying means on the upstream bearing and the downstream bearing and a pump for simultaneous feeding of the first and second oil spraying means.

Description

(1) The invention will be better understood, and other details, characteristics and advantages of the invention will appear upon reading the following description given by way of a non restrictive example while referring to the appended drawings wherein:

(2) FIG. 1 is a schematic axial sectional half-view of an epicycloidal gear train reducer in a turbomachine according to the invention;

(3) FIG. 2 is a truncated schematic perspective view of the gear train reducer and of the satellite lubrication means;

(4) FIG. 3 is a schematic sectional view of an impeller according to the invention.

(5) First of all, we refer to FIG. 1, which schematically represents a reducer 10, according to the invention, with epicycloidal gear trains mounted in a turbomachine such as an aircraft turbojet. Specifically, the gear train 10 is mounted in a radially formed annular chamber 12 inside a low-pressure compressor 14 arranged downstream of the fan wheel 16 and upstream of a high-pressure compressor (not shown). The low-pressure compressor 14 comprises a plurality of rows of fixed vanes 18 and annular rows of moving vanes 20 arranged axially, along axis A, alternately. The rows of moving vanes 20 are connected by an annular wall 22 to a low-pressure shaft 24, which also rotates the vanes of a downstream low-pressure turbine (not shown).

(6) The gear train reducer 10 comprises a central pinion 26 or planetary pinion surrounding the upstream end of the shaft 24 of the low-pressure compressor and fixed to it, an outer crown 28 or planetary ring gear surrounding the central pinion 26 and fixedly connected to an annular wall 30 defining internally the flow vein of the primary air flow (arrow B) flowing in the low-pressure compressor 14. The reducer 10 also includes satellite pinions 32 which are engaged by their teeth with gears of the central pinion 26 and the outer crown 28. These satellite pinions 32 are mounted freely rotating on axes 34 of a satellite carrier 36 whose upstream end is connected by a connecting shaft 38 to the fan wheel 16.

(7) The shaft 24 of the low-pressure compressor 14 is supported and guided in rotation by a downstream ball bearing 40 whose outer ring 40a is fixed to a first stator part 42 of the low-pressure compressor 14 connected externally to the inner annular wall 30 of the primary air vein. The connecting shaft 38 is supported and guided in rotation by two bearings 44, 46 arranged upstream of the reducer 10, among which a first bearing 44 arranged upstream of a second bearing 46 is a roller bearing, the second bearing 46 being a ball bearing. The outer crowns 44a, 46a of the first and second bearings are supported by a second stator part 48 of the low-pressure compressor connected externally to the inner annular wall 30 of the primary air vein.

(8) The annular chamber 12 of the epicycloidal gear train reducer 10 is thus delimited radially inwardly by the shaft 24 of the low-pressure compressor 14, radially outwardly by the first 42 and second 48 stator parts and the inner annular wall 30 of the primary air vein, upstream by the first upstream bearing 44 and downstream by the downstream bearing 40. It should be noted that the connecting shaft 38 also includes an annular wall 50 that cooperates sealingly with the upstream end 52 of the shaft 24 of the low-pressure compressor 14 to prevent lubricating oil leaks at this point. Similarly, to limit oil leaks, the outer crown 44a of the first upstream bearing 44 and the outer crown 40a of the downstream bearing 40 each have an annular portion 44b, 40b cooperating sealingly with the connecting shaft 38 and the shaft 24 of the low-pressure compressor 14.sup.1, respectively. .sup.1 Note du traducteur: erreur de référence dans la source

(9) The rotation of the satellite pinions 32 in the axes 34 of the satellite carrier is carried out by means of sliding bearings.

(10) The epicycloidal gear train reducer 10 includes lubrication means by spraying oil on the gear teeth of satellite pinions 32 and their axes 34, these means including a first oil circuit and a second oil circuit that are independent and which receive the oil from an impeller 54 arranged downstream of the reducer 10 and having an annular cup 56, more particularly circular in shape (FIG. 2). The cup 56 has a U-shaped section, the opening of which is oriented radially towards the axis A, i. e. towards the low pressure shaft 24. The cup 56 of the impeller 54 comprises a cylindrical bottom wall 58 connected at its upstream and downstream axial ends to radial annular walls 56a, 56b (FIG. 2). The cup 56 is circumferentially divided into a succession of basins 60, 62 separated circumferentially by radially oriented walls 64 and extending axially between the two radial ring walls 56a, 56b. In the example shown in FIG. 3, the circumferential separation walls 64 delimit first basins 60 alternating with second basins 62. The first basins 60 belong to the first oil circuit and the second basins belong to the second oil circuit. As it can be seen, the first basins 60 may have a smaller angular range than the second basins 62.

(11) The first basins 60 each have an oil outlet port formed in the bottom cylindrical wall 58 and leading into first oil supply lines 66 of the contact area between the teeth of the satellite pinions 32 and the teeth of the central pinion 26 (FIGS. 2 and 3). The second basins 62 each have an oil outlet port formed in the bottom cylindrical wall 58 and opening into second oil supply lines 68 of the axes 34 of the satellite pinions 32 (FIGS. 2 and 3). In FIG. 3, hole 67 allows the annular cup 56 to be fixed to the satellite carrier 36.

(12) The first basins 60 are different from the second basins 62 and the differences are essentially intended to ensure an optimal oil supply to the elements arranged at different radial positions. These differences also make it possible to direct the excess oil away from the reducer and force lubrication of the elements closest to the shaft, i. e. the contact area between the teeth of the satellite pinion 32 and the teeth of the central pinion 26. Thus, the second basins may be shallower than the first basins.

(13) Oil spraying means are also provided and include a plurality of oil nozzles 72 distributed around axis A and connected to a pump and an oil tank (FIG. 1). In an embodiment of the invention, oil nozzles 72 are orifices arranged on a fixed ring 70 surrounding the shaft 24. This ring 70 is mounted in the radial space between the annular cup 56 and the shaft 24. These nozzles 72 are oriented so that their oil jets project oil towards the cup 70, between the radial annular walls 56a, 56b. The projection direction is preferably radial, possibly slightly inclined downstream, upstream or according to the direction of rotation, i.e. the projection direction is included in an angular cone with a radial axis and an opening of 20°.

(14) The diameter of a nozzle 72 must be greater than the maximum diameter of the particles likely to clog the nozzles. The diameter must also be large enough to ensure a flow of oil to the cup 56 and energetic enough to be straight over a distance of about 5 cm. In a practical embodiment of the invention, the oil spraying means are configured to have an outlet pressure of about 1 bar in the least favourable regimes such as idling. If you want to move the nozzles 72 away from the cup, you must increase the oil pressure.

(15) As shown in FIG. 3, the downstream radial annular wall 56b of the cup 56, i. e. the radial annular wall 56b furthest from a median radial plane 74 of the reducer 10, has openings 76 having in the example shown the shape of notches that open into the second basins 62. These notches 76 are formed in the radially inner annular edge 75 of the radial wall downstream 56b. In particular, the notches are formed in the portions of the downstream radial annular wall 56b defining the second basins 62 laterally. In this way, it can be seen that the downstream radial annular wall 56b forms a notched annular wall. With such an arrangement, it is possible to better regulate the oil flow to the first and second oil circuits. Indeed, when the oil flow supplying the nozzles 72 is regulated by a pump whose output flow is directly proportional to the speed of a shaft of the high-pressure compressor, it follows that in the idling phase the oil flow may be too high in the second oil circuit supplying the axes of the satellite pinions 32, which is avoided by making slots 76 on the portions of the downstream radial annular wall 56b of the second basins 62. The excess oil (arrow 78) then flows through the notches directly onto the frustoconical wall 30 of the low-pressure compressor 14 on contact with which the oil cools. The oil then flows by gravity to the lowest point of the turbomachine and is collected by a collector arranged at six o'clock in relation to the dial of a watch.

(16) In a particular embodiment of the invention, the notches may have a depth P1, in radial direction, of the order of 20 to 50% of the depth P2 of the first basins 60.

(17) Of course, notches 76 could be replaced by circular or oblong openings providing the same function of regulating the quantity of oil. Thus, the term opening refers to a passage in the annular wall of the cup 56 which is the furthest from the median plane 74 of the reducer 10, i. e. with reference to the figures the downstream radial annular wall 56b of the cup 56. It is understood that the opening could have many forms, all of which fall within the scope of the protection conferred on the invention.

(18) With reference again to FIG. 1, the turbomachine also includes second oil spraying means 80 on the upstream roller bearings 44, 46 and the downstream bearing 40. These first 70 and second 80 oil spraying means are integrated into the same oil circuit 82 which also includes a pump 84. This pump 84 simultaneously supplies the first oil spraying means 70 supplying the epicycloidal reducer 10 and the second supply means of the bearings 40, 44, 46.

(19) Thus, the assembly according to the invention of an annular bailer fixed to the shaft makes it possible to ensure a centrifugation of the oil at low speed and it is possible to have a feed pump whose operating speed does not need to be a function of the rotational speed of the shaft 24 driving the central pinion. In a particular configuration, the operating speed of the pump can also be chosen to be dependent on the speed of a high-pressure shaft of the turbomachine such as the high-pressure compressor shaft.