Planetary gearing

Patent metadata

Field	Value
Publication number	US-11085523-B2
Application number	US-201816198172-A
Country	US
Kind code	B2
Filing date	Nov 21, 2018
Priority date	Nov 24, 2017
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

A planetary gearing includes a sun gear rotating about a rotation axis and driven by a sun shaft; planet gears driven by the sun gear, each planet gear having an axially forward face side and an axially rearward face side; a ring gear engaging the planet gears; and planet slide bearing pins, wherein respectively one planet slide bearing pin is arranged inside a planet gear forming a lubricated journal bearing. At an axially forward face side and/or axially rearward face side, each planet gear forms a recess that extends inside the planet gear starting from the face side, and the planet slide bearing pins respectively form one crowning at their abutment surface such that their outer diameter decreases from a maximum outer diameter to at least an axial end of the abutment surface and has a minimum at the axial end.

First claim

The invention claimed is:

1. A planetary gearing, comprising:
a sun gear rotatable about a rotation axis of the planetary gearing and driven by a sun shaft, wherein the rotation axis defines an axial direction of the planetary gearing,
a plurality of planet gears that are driven by the sun gear, wherein each planet gear has an axially forward face side and an axially rearward face side and includes an outer shell surface that includes a toothing that is a double helical gearing,
a ring gear with which the plurality of planet gears is in engagement,
a plurality of planet slide bearing pins, respectively having an outer-side abutment surface that comprises an axially forward end and an axially rearward end,
wherein respectively one planet slide bearing pin is arranged inside a planet gear, and the planet slide bearing pin and the planet gear form a lubricated journal bearing,
wherein, each planet gear includes a forward recess that extends inside the planet gear starting from the axially forward face side and a rearward recess that extends inside the planet gear starting from the axially rearward face side, and
wherein the abutment surface is crowned with an outer diameter decreasing from a maximum outer diameter towards at least one chosen from the axially forward end and the axially rearward end and having at least one minimum outer diameter at the at least one chosen from the axially forward end and the axially rearward end,
wherein the forward recess and the rearward recess are asymmetrical with respect to one another with respect to an axial center of the planet gear.

2. The planetary gearing according to claim 1 , wherein a radial thickness of at least one chosen from the forward recess and the rearward recess decreases with growing distance from a respective one of the axially forward face side and the axially rearward face side.

3. The planetary gearing according to claim 2 , wherein each planet gear further comprises:
an inner shell surface,
at least one chosen from the axially forward face side and the axially rearward face side:
an outer face side area extending from a respective one of the forward recess and the rearward recess outwardly to the outer shell surface, wherein the outer face side area forms a radially inner face side edge to the respective one of the forward recess and the rearward recess and a radially outer face side edge to the outer shell surface,
an inner face side area extending from the respective one of the forward recess and the rearward recess inwardly to the inner shell surface, wherein the inner face side area forms a radially outer face side edge to the respective one of the forward recess and the rearward recess and a radially inner face side edge to the inner shell surface,

wherein the radial thickness of the respective one of the forward recess and the rearward recess is defined as a radial distance between the radially inner face side edge of the outer face side area and the radially outer face side edge of the inner face side area.

4. The planetary gearing according to claim 3 , wherein, also adjacent to the inner face side area, a radially inner boundary of the respective one of the forward recess and the rearward recess forms an angle to the axial direction that is between 0° and 45°.

5. The planetary gearing according to claim 3 , wherein, also adjacent to the outer face side area, a radially outer boundary of the respective one of the forward recess and the rearward recess forms an angle to the axial direction that is between 0° and 45°.

6. The planetary gearing according to claim 3 , wherein
the outer shell surface has an axial length,
the inner shell surface has an axial length,
a thickness of the planet gear is defined by a radial distance between the inner shell surface and a tooth base plane of the toothing.

7. The planetary gearing according to claim 6 , wherein a ratio of the radial thickness of the respective one of the forward recess and the rearward recess at the face side to the thickness of the planet gear is between 0.1 and 0.9.

8. The planetary gearing according to claim 6 , wherein a ratio of the radial thickness of the inner face side area to the thickness of the planet gear is between 0.01 and 0.6.

9. The planetary gearing according to claim 6 , wherein a ratio of an axial length of the respective one of the forward recess and the rearward recess to half the axial length of the inner shell surface is between 0.01 and 0.9, wherein the axial length of the respective one of the forward recess and the rearward recess is measured starting from the inner face side area.

10. The planetary gearing according to claim 6 , wherein the axial length of the outer shell surface is not equal to the axial length of the inner shell surface.

11. The planetary gearing according to claim 1 , wherein, at an end formed in the planet gear, at least one chosen from the forward recess and the rearward recess is formed by a substantially radially extending surface that transitions via rounded corners into a radially outer boundary and into a radially inner boundary of the at least one chosen from the forward recess and the rearward recess.

12. The planetary gearing according to claim 11 , wherein at least one chosen from the radially outer boundary and the radially inner boundary is formed to be at least one chosen from rectilinear, circular and parabolic in a longitudinal section.

13. The planetary gearing according to claim 12 , wherein the at least one chosen from the forward recess and the rearward recess extends in a circumferential direction of the planet gear by 360°.

14. The planetary gearing according to claim 1 , and further comprising a torque carrier, wherein the plurality of planet slide bearing pins are coupled with the torque carrier, and the torque carrier rotates about the rotation axis of the planetary gearing, with the sun gear rotating and the ring gear being fixedly attached.

15. The planetary gearing according to claim 14 , and further comprising at least one chosen from:
wherein the plurality of planet slide bearing pins have respectively, axial openings at inner sides for receiving support slide bearing pins of the torque carrier,
and
further comprising a forward support plate and a rearward support plate and wherein the plurality of planet slide bearing pins are fixedly connected to the forward support plate and to the rearward support plate, wherein the forward support plate is coupled with the torque carrier for torque transmission.

16. A gear fan engine, comprising:
a fan stage,
a fan shaft via which the fan stage is driven,
a turbine shaft,
wherein the turbine shaft and the fan shaft are coupled via the planetary gearing according to claim 1 , wherein the turbine shaft forms the sun shaft, the planet slide bearing pins are coupled with a torque carrier and the torque carrier is coupled with the fan shaft.

Assignees

• Rolls Royce Deutschland Ltd & Co Kg
• Rolls Royce Plc

Inventors

• Nique Michael
• Gorenz Paul
• Campbell Christopher
• Wagner Frank
• Spruce Mark
• Ashmore Daren

Classifications

• F05D2260/98

  Lubrication · CPC title

• F02C7/36 Primary

  Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user ({F02C3/107 - F02C3/13 and} F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H) · CPC title

• F16H57/0486

  with fixed gear ratio  (axle or inter-axle differentials F16H57/0483) · CPC title

• F16H57/0479

  Gears or bearings on planet carriers · CPC title

• F16C23/04

  self-adjusting · CPC title