阅读说明：本技术 行星齿轮系 (Planetary gear train ) 是由 阿德里安·路易斯·西蒙 西蒙·洛伊克·克莱门特·勒费布尔 纪尧姆·让·皮埃尔·罗比内特 于 2018-11-29 设计创作，主要内容包括：本发明涉及一种行星齿轮系(1),该行星齿轮系包括第一行星齿轮(2)、第二行星齿轮(3)、与第一行星齿轮(2)和第二行星齿轮(3)相接合的多个行星齿轮(4),每个行星齿轮(4)被安装成围绕轴(5)枢转,支撑每个轴(5)的行星齿轮架(6),其特征在于,每个轴(5)沿轴线(B)延伸并且包括：安装在行星齿轮架(6)上的径向内部圆柱形部分(18)；径向外部圆柱形部分(19),行星齿轮(4)围绕该径向外部圆柱形部分(19)被安装以用于枢转；以及从径向外部圆柱形部分(19)径向延伸的端板(20),端板(20)的径向外周边被安装在行星齿轮架(6)上,径向外部圆柱形部分(19)和径向内部圆柱形部分(18)通过径向延伸的连接区域(24)而彼此连接。(The invention relates to a planetary gear train (1) comprising a first planetary gear (2), a second planetary gear (3), a plurality of planetary gears (4) engaged with the first planetary gear (2) and with the second planetary gear (3), each planetary gear (4) being mounted to pivot about a shaft (5), a planetary carrier (6) supporting each shaft (5), characterized in that each shaft (5) extends along an axis (B) and comprises: a radially inner cylindrical portion (18) mounted on the planet carrier (6); a radially outer cylindrical portion (19) about which the planet gear (4) is mounted for pivoting; and an end plate (20) extending radially from the radially outer cylindrical portion (19), a radially outer periphery of the end plate (20) being mounted on the planet carrier (6), the radially outer cylindrical portion (19) and the radially inner cylindrical portion (18) being connected to each other by a radially extending connecting region (24).)

1. Planetary gear train (1) comprising:

-a first planetary gear (2),

-a second planetary gear (3),

-pinions (4) in mesh with the first planet gears (2) and the second planet gears (3), each pinion (4) being pivotally mounted about an axle (5),

-a pinion carrier (6) supporting each shaft (5), characterized in that each shaft (5) extends along an axis and comprises: a radially inner cylindrical portion (18) mounted on the pinion carrier (6); a radially outer cylindrical portion (19) about which the pinion (4) is pivotally mounted; and a flange (20) extending radially from the radially outer cylindrical portion (19), a radially outer periphery of the flange (20) being mounted on the pinion carrier (6), the radially outer cylindrical portion (19) and the radially inner cylindrical portion (18) being connected to each other by a radially extending connecting region (24).

2. Epicyclic gear (1) according to claim 1, wherein the pinion carrier (6) has a first radially extending annular flange (12) and a second radially extending annular flange (13), the first and second flanges (12, 13) being axially offset from each other and connected to each other by a plurality of axially extending connecting members (14).

3. Epicyclic gear (1) according to claim 2, wherein the flange (20) of each shaft (5) is mounted on the first side (12) of the pinion carrier (6) and the radially inner cylindrical portion (18) of each shaft (5) is mounted on the second side (13) of the pinion carrier (6).

4. Epicyclic gear (1) according to any of claims 1 to 3, wherein the first planet gears (2) are located radially inside the pinion gears (4) and the second planet gears (3) are located radially outside the pinion gears (4).

5. Epicyclic gear train (1) according to any of claims 1 to 4, wherein the first planet gear (2), the second planet gear (3) and the plurality of pinion gears (4) each have a first annular tooth (9a, 11a, 27a) and a second annular tooth (9b, 11b, 27b), the first annular teeth (9a, 11a, 27a) and the second annular teeth (9b, 11b, 27b) being axially offset from each other, the first tooth (11a) of each pinion gear (4) meshing with the first tooth (9a) of the first planet gear (2) and with the first tooth (27a) of the second planet gear (3), the second tooth (11b) of each pinion (4) meshes with the second tooth (9b) of the first planetary gear (2) and with the second tooth (27b) of the second planetary gear (3).

6. Epicyclic gear (1) according to any of claims 1 to 5, wherein the pinion carrier (6) is made of the same material as the shafts (5).

7. Epicyclic gear (1) according to any one of claims 1 to 6, wherein the radially inner cylindrical portion (18) and the radially outer cylindrical portion (19) are tubular, the thickness (e0) of the radially inner cylindrical portion (18) being smaller than the thickness (e1) of the radially outer cylindrical portion (19).

8. Epicyclic gear (1) according to any of claims 1 to 7, wherein the stiffness constant kc of the pinion carrier (6) or the stiffness constant kp of each shaft, the stiffness constants of the pinion carrier (6) and the shafts (5) are tailored such that 0.5kc < kp <2 kc.

Technical Field

The present invention relates to a planetary gear train for a turbomachine, such as an aircraft turbojet or turboprop.

Background

In the case of a turbojet, the planetary gear train makes it possible in particular to couple the blower to a shaft integral with the rotor of the compressor and/or of the turbine. This makes it possible to set the rotation speed of the blower different from the rotation speed of the turbine rotor.

The planetary gear train may also be used to couple the propeller of a turboprop engine to a shaft coupled to the rotor of the turbine so that the rotational speed of the propeller may be adjusted as desired.

The use of such a planetary gear train in a turbine engine is known in particular from document US 9038779. In this document, the planetary gear train includes inner and outer planetary gears, pinions that mesh with the inner and outer planetary gears, each pinion being pivotally mounted about an axle, and a pinion carrier that supports each axle.

During operation, high torque is transmitted through the planetary gear train, which can distort the pinion carrier and create misalignment of the pinions relative to the inner and outer sun gears, resulting in reduced performance of meshing and wear of the teeth. In order to avoid misalignment of the running pinions, document WO 2014/046960 proposes to arrange spacers between the pinions in order to absorb the forces and ensure that the sun gear shaft remains parallel to the axes of the inner and outer planet gears.

The use of additional spacers increases the complexity, cost and mass of the planetary gear train.

Disclosure of Invention

The present invention aims to remedy such drawbacks in a reliable and inexpensive manner.

To this end, the invention relates to a planetary gear train comprising:

-a first sun gear to be engaged with the first gear,

-a second sun gear which is connected to the first sun gear,

-a pinion in mesh with the first and second sun gears, each pinion being pivotally mounted about an axis,

-a pinion carrier supporting each shaft, wherein each shaft extends along an axis and comprises: a radially inner cylindrical portion mounted on the pinion carrier; a radially outer cylindrical portion about which the pinion is pivotally mounted; and a flange extending radially from the radially outer cylindrical portion, a radially outer periphery of the flange being mounted on the pinion carrier, the radially outer cylindrical portion and the radially inner cylindrical portion being connected to each other by a radially extending connecting region.

In this way, an annular space is present between the radially inner cylindrical portion and the radially outer cylindrical portion. Such a configuration allows for controlled deformation of the shaft at the flange, cylindrical portion or connection area to compensate for the deformation of the pinion carrier. In this way, good meshing performance between the pinion and the planet gear is maintained, while premature wear of the teeth is avoided.

The pinion carrier may have a first radially extending annular first flange and a second radially extending annular second flange, the first and second flanges being axially offset from one another and connected to one another by a plurality of axially extending connecting members.

The flange of each shaft may be mounted on a first side of the pinion carrier and the radially inner cylindrical portion of each shaft is mounted on a second side of the pinion carrier.

The first sun gear may be located radially inward of the pinion gear and the second planet gears may be located radially outward of the pinion gear.

The first and second planet gears and the sun gears may each have first and second annular teeth axially offset from each other, the first tooth of each sun gear being in mesh with the first tooth of the first planet gear and with the first tooth of the second planet gear, the second tooth of each sun gear being in mesh with the second tooth of the first planet gear and with the second tooth of the second planet gear.

The outer planet gears may have a first ring with first teeth and a second ring with second teeth.

The planet carrier may be made of the same material as the shafts or of two different materials.

The planet carrier and the shaft are made of steel or titanium, for example.

The planetary gear train may have a cover, wherein the pinion carrier, the pinions, and the shafts are at least partially housed in the cover.

The lid may include a first annular portion and a second annular portion that define the volume.

The inner and outer sun gears are intended to rotate and the pinion carrier and shaft are intended to remain stationary during operation.

The inner planetary gears may also be referred to as sun gears. The outer planet gears are also referred to as crown gears.

The radially inner and outer cylindrical portions may be tubular, the radially inner cylindrical portion having a thickness less than a thickness of the radially outer cylindrical portion.

With kc as the stiffness constant of the pinion carrier and kp as the stiffness constant of each axle, the stiffness constants of the pinion carrier and the axles can be tailored such that 0.5kc < kp <2 kc. The definition of the stiffness constant is given below.

The invention also relates to a turbine engine, such as an aircraft turbine engine or a turboprop engine, having a planetary gear train of the type described above.

The invention will be better understood and other details, characteristics and advantages thereof will appear, when the following description is read in conjunction with the accompanying drawings, given as a non-limiting example.

Drawings

Figure 1 is an exploded perspective view of a planetary gear train according to an embodiment of the invention;

figure 2 is an axial section view of the planetary gear train;

FIG. 3 is a detailed view of a portion of FIG. 2;

figure 4 is a perspective view of the pinion shaft;

figure 5 schematically shows the deformation of the first side of the pinion carrier when a force fc is applied at the edge of the opening of the first side;

fig. 6 schematically shows the deformation dp of the shaft when a force fp is applied to the shaft.

Detailed Description

Fig. 1 to 4 show a planetary gear train 1 according to an embodiment of the present invention. This includes the inner planet gears 2 or sun gears, the outer sun gear 3 or ring gear, the pinion gears 4 rotatably mounted on shafts 5, and a pinion carrier 6, the shafts 5 of the pinion gears 6 being mounted on the pinion carrier 6. The planetary gear train 1 also has a cover 7 or a ring gear carrier.

The inner planet gear 2 is annular with an axis a, and the inner planet gear 2 has a first annular and radially outer, axially offset first tooth 9a and a second annular and radially outer tooth 9 b.

Each pinion 4 is annular and has a radially inner cylindrical surface 10. Each pinion 4 also includes first and second teeth 11a, 11b axially offset from one another, which mesh with the first and second teeth 9a, 9b, respectively, of the inner sun gear 2.

The pinion carrier 6 has a first annular side 12 and a second annular side 13 axially offset from each other and connected by an axially extending connecting member 14. The first side 12 has a circular opening 15 of axis B. The second side 13 has a hole 16 of axis B, positioned axially opposite the circular opening 15 of the first side. The link portion 14 defines a slot 17 for mounting the pinion 4. Said housing 17 is open radially outwards so as to allow radial mounting of the pinion 4 in said housing 17 of the pinion carrier 6.

Each shaft 5 extends along a respective axis B and comprises a radially inner cylindrical portion 18, a radially outer cylindrical portion 19 about which the pinion 4 is pivotally mounted, and a flange 20 extending radially from the radially outer cylindrical portion 19 the radially outer periphery of the flange 20 has a cylindrical flange 20a, one end of which, called the front end, extends through a radial flange 20B so that it has a substantially L-shaped section the outer surface of the cylindrical flange 20a is mounted with no or little play in the opening 15 of the first flange 12 of the pinion carrier 6 the radial flange 20B is axially supported on the radially front surface of the first side 12.

Said inner cylindrical portion 18 has more specifically a first zone 21 or front zone having a smaller diameter than a second zone 22 or rear zone. The rear region 22 is mounted with no or little play in the bore 16 of the second side 13 of the pinion carrier 6. The second region 22 has an annular groove 23 on its radially outer surface.

The outer diameter of the second region 22 is denoted d 0. The thickness of the first region 21, i.e. the radial distance between the inner and outer surfaces of the first region 21, is denoted e 0. The outer diameter of the first region 21 is denoted d 3. The first region 21 is dimensioned to provide flexibility in the first region 21.

The outer diameter of the radially outer cylindrical portion 19 is denoted d 1. The thickness of the radially outer cylindrical portion 19, i.e. the radial distance between the outer surface and the inner surface, is denoted e 1.

The width of the radial annular part 20 of the flange, i.e. the axial dimension of said radial annular part 20, is denoted l 2. The outer diameter of the flange 20a is indicated as d 4. The width l2 is defined to provide flexibility at the flange 20.

The outer radial cylindrical portion 19 and the inner radial cylindrical portion 18 are connected to each other by a radially extending annular connecting region 24. In particular, the connecting region 24 connects one end, in particular the front end, of the intermediate region of the inner cylindrical portion 18 and the outer cylindrical portion 19. An annular space 25 is formed between the radially inner cylindrical portion 18 and the radially outer cylindrical portion 19. The minimum width of the connection region 24, i.e. the minimum axial distance from the connection region 24, is denoted 13.

The dimensions d0, d1, d3 and d4 are defined such that d3< d0< d1< d 4. Further, the dimensions e0 and e1 are defined such that e0 ≦ e 1.

The shaft 5 and the pinion carrier 6 are made of, for example, steel or titanium.

Fig. 5 schematically shows the deformation dc of the first side 12 of the pinion carrier 6 when a force fc is applied at the edge of the opening 15 and the second side 13 is defined as stationary. The value of the force applied to each opening 12 is equal to fc/n for n openings 12, these forces being evenly distributed over the different openings 12. This force fc results in a displacement dc of each opening 12. After said displacement, the opening 12 is shown in dashed lines. The stiffness constant kc of the pinion carrier 6 is defined by the equation kc ═ fc/dc.

Fig. 6 schematically illustrates the deformation dp of the shaft 5 when a force fp is applied to the shaft and the outer periphery of the flange 20 and the second region 22 of the inner member 18 are considered stationary. The flange 20 and the first region 21 of the inner member 18 are shown as springs due to their flexibility or suppleness. The dashed part shows the part after deformation. The stiffness constant kp of the shaft 5 is defined by the equation kp fp/dp.

It has been calculated that the stiffness constants of the different parts of the pinion carrier 6 and the shaft 5 should be tailored such that 0.5kc < kp <2kc, such that misalignment of the shaft 5 is considered acceptable.

The outer planet gears 3 comprise a first ring 26 and a second ring 27 axially offset from each other. As can be better seen in fig. 3, each ring 26, 27 has a radially inner annular portion 26a, 27a with radially inner teeth 26b, 27 b. The first ring 26 carries first teeth 26a which mesh with the first teeth 11a of each pinion 4. The second ring 27 carries a second tooth 27b which meshes with the second tooth 11b of each pinion 4. Each ring 26, 27 also has a radially extending radially outer flange 26c, 27 c. Finally, each ring 26, 27 has an inclined connecting wall 26d, 27d connecting the outer flange 26c, 27c and the inner annular part 26a, 27 a. The connecting wall 26d of the first ring 26 widens toward the second ring 27. The connecting wall 27d of the second ring 27 widens towards the first ring 26. The radially inner periphery of the flange 26c of the first ring 26 has an annular centering flange 28, which annular centering flange 28 engages in a correspondingly shaped recess 29 of the flange 27c of the second ring 27. The two flanges 26c, 27c are axially supported on each other. The cap 7 is attached to the flanges 26c, 27c of the first and second rings 26, 27. The cover 7 comprises a first part 30 or front part and a second part 31 or rear part, each part 30, 31 having a radial annular flange 30a, 31a on the radially outer periphery. The flanges 30a, 31a of the parts 30, 31 of the cover 7 are axially fixed on both sides of the flanges 26c, 27c of the bush, for example by welding or bolting. The first part 30 and the second part 31 of the cover 7 delimit an annular internal volume housing, at least partially delimiting the pinion 4, the shaft 5 and the pinion carrier 6.

In operation, the planetary gear train 1 according to the invention can transmit a high torque, which can have the effect of slightly deforming the pinion carrier 6, in particular at the second side 13. The structure of the shafts 5 allows them to deform at the flanges 20, the cylindrical portions 18, 19 or the connecting zones 24, in order to compensate for the deformation of the pinion carrier 6. In this way, good meshing performance between the pinion 4 and the planet gears 2, 3 is maintained, while premature wear of the teeth 9a, 9b, 11a, 11b, 27a, 27b is avoided.