Planetary gear stage with plain bearings as planet bearings and use thereof

Patent metadata

Field	Value
Publication number	US-9416867-B2
Application number	US-201314398132-A
Country	US
Kind code	B2
Filing date	Apr 9, 2013
Priority date	May 8, 2012
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

A planetary gear stage for a gearbox has a ring gear, a sun gear and a planet carrier for driving planet shafts. Each planet shaft has a planet gear with radial and axial contact surfaces and which is rotatably supported by a plain bearing arrangement. The bearing arrangement has two bushings fixed to the planet shaft. Each bushing is L-shaped in cross-section and has radial and axial contact surfaces. The bushings form a cross-sectional U-shape and are axially locked by abutments. At least part of the planet gear is located within the U-shape formed by the bushings. The plain bearing arrangement has a radial sliding support arranged between the radial contact surface of the bushings and the radial contact surface of the planet gear and an axial sliding support arranged between the axial contact surface of the bushings and the axial contact surface of the planet gears.

First claim

The invention claimed is:

1. A planetary gear stage ( 2 ) for a gearbox ( 1 ), the planetary gear stage ( 2 ) comprising:
a ring gear ( 8 ), a sun gear ( 9 ) and a planet carrier ( 4 ) for driving at least three planet shafts ( 6 ), at least one planet gear ( 5 ) is rotatably mounted on each of the at least three planet shafts by a respective plain bearing arrangement ( 7 ), and each of the planet gears ( 5 ) having a radial contact surface ( 18 ) and an axial contact surface ( 20 ),
each of the plain bearing arrangements ( 7 ) comprising:
two bushings ( 12 ) fixedly connected to the planet shaft ( 6 ), each of the two fixed bushings ( 12 ) being L-shaped in cross-section and having a radial contact surface ( 13 ) and an axial contact surface ( 14 ), the fixed L-shaped bushings ( 12 ) being mounted to form a cross-sectional U-shape and being locked in an axial direction at both outer sides by an abutment ( 15 , 16 , 24 ), and at least part of the planet gear ( 5 ) is located within the U-shape formed by the fixed L-shaped bushings ( 12 ),
a radial sliding support ( 17 ) arranged directly in between the radial contact surface ( 13 ) of the fixed L-shaped bushings ( 12 ) and the radial contact surface ( 18 ) of the planet gear ( 5 ), and
an axial sliding support ( 19 ) arranged in between the axial contact surface ( 14 ) of the fixed L-shaped bushings ( 12 ) and the axial contact surface ( 20 ) of the planet gears ( 5 ).

2. The planetary gear stage ( 2 ) according to claim 1 , wherein a contact surface angle (a) of the axial contact surfaces ( 14 , 20 ) of the fixed L-shaped bushings ( 12 ) and the planet gear ( 5 ) is between +0.2° and +2.5° from an axis that is perpendicular to the radial contact surface of the planet gear.

3. The planetary gear stage ( 2 ) according to claim 2 , wherein the contact surface angle (a) of the axial contact surfaces ( 14 , 20 ) of the fixed L-shaped bushings ( 12 ) and the planet gear ( 5 ) is between +0.5° and +1.5° from the axis that is perpendicular to the radial contact surface of the planet gear.

4. The planetary gear stage ( 2 ) according to claim 1 , wherein the L-shaped bushings ( 12 ) having a width (W) and the planet shaft ( 6 ) having a diameter (d), and a ratio of the width (W) of the L-shaped bushings ( 12 ) to the diameter (d) of the planet shaft ( 6 ) is either equal to or larger than 0.3.

5. The planetary gear stage ( 2 ) according to claim 1 , wherein the L-shaped bushings ( 12 ) having a width (W) and the planet shaft ( 6 ) having a diameter (d), and a ratio of the width (W) of the L-shaped bushings ( 12 ) to the diameter (d) of the planet shaft ( 6 ) is either equal to or larger than 0.5.

6. The planetary gear stage ( 2 ) according to claim 1 , wherein the L-shaped bushings ( 12 ) axially abut each other and are fixed against rotation with respect to the planet shaft ( 6 ) by a positioning element ( 21 ) which engages both of the fixed L-shaped bushings.

7. The planetary gear stage ( 2 ) according to claim 6 , wherein the positioning element ( 21 ) is a key provided in a keyway in the planet shaft ( 6 ).

8. The planetary gear stage ( 2 ) according to claim 1 , wherein the fixed L-shaped bushings ( 12 ) are fixedly connected together and have axial sides that abut each other.

9. The planetary gear stage ( 2 ) according to claim 1 , wherein the plain bearing arrangement ( 7 ) comprises a spacer ( 22 ) arranged in between the fixed L-shaped bushings ( 12 ), and the spacer abuts axial sides of the fixed L-shaped bushings and axially separates the fixed L-shaped bushings from each other.

10. The planetary gear stage ( 2 ) according to claim 1 , wherein the plain bearing arrangement ( 7 ) comprises at least one further bushing ( 23 ) that is axially located between the fixed L-shaped bushings ( 12 ), and the at least one further bushing axially separates the fixed L-shaped bushings from each other.

11. The planetary gear stage ( 2 ) according to claim 1 , wherein opposed axial ends of the radial sliding support ( 17 ) are axially spaced from the respective axial contact surfaces ( 14 ) of the fixed L-shaped bushings ( 12 ) by gaps, and the radial sliding support comprises a coating ( 17 ) of plain bearing material provided at least on the radial contact surface ( 13 ) of the L-shaped fixed bushings ( 12 ).

12. The planetary gear stage ( 2 ) according to claim 1 , wherein the axial sliding support ( 19 ) comprises a coating ( 19 ) of plain bearing material provided on at least one of:
the axial contact surface ( 14 ) of the fixed L-shaped bushings ( 12 ), and
the axial contact surface ( 20 ) of the planet gears ( 5 ).

13. The planetary gear stage ( 2 ) according to claim 1 , wherein the planet carrier ( 4 ) is a double flange planet carrier.

14. The planetary gear stage ( 2 ) according to claim 13 , wherein the abutments for locking the L-shaped bushings ( 12 ) in the axial direction are formed at one outer side by an abutment ( 15 ) of the planet carrier ( 4 ) and at the other outer side by a collar ( 16 ) of the planet shaft ( 6 ).

15. The planetary gear stage ( 2 ) according to claim 1 , wherein the planet carrier ( 4 ) is a single flange planet carrier.

16. The planetary gear stage ( 2 ) according to claim 15 , wherein the abutments for locking the L-shaped bushings ( 12 ) in the axial direction are formed at one outer side by an abutment ( 15 ) of the planet carrier ( 4 ) and at the other outer side by a locking mechanism ( 24 ).

17. The planetary gear stage ( 2 ) according to 1 , wherein the planet carrier ( 4 ) comprises a backplate ( 26 ).

18. The planetary gear stage ( 2 ) according to claim 17 , wherein the abutments for locking the L-shaped bushings ( 12 ) in the axial direction are formed, at both outer sides, by a locking mechanism ( 24 ).

19. The planetary gear stage ( 2 ) according to claim 1 , wherein at least two planet gears ( 5 ) are rotatably mounted on a common planet shaft ( 6 ).

20. The planetary gear stage ( 2 ) according to claim 1 , wherein the planetary gear stage ( 2 ) is incorporated into a gearbox ( 1 ) of a wind turbine.

21. A planetary gear stage ( 2 ) for a gearbox ( 1 ), the planetary gear stage ( 2 ) comprising:
a ring gear ( 8 ), a sun gear ( 9 ) and a planet carrier ( 4 ) for driving at least three planet shafts ( 6 ), at least one planet gear ( 5 ) is rotatably mounted on the at least three planet shaft by a plain bearing arrangement ( 7 ), and each of the planet gears ( 5 ) having a radial contact surface ( 18 ) and an axial contact surface ( 20 ),
each of the plain bearing arrangements ( 7 ) comprising:
two bushings ( 12 ) fixedly connected to the planet shaft ( 6 ), each of the two fixed bushings ( 12 ) being L-shaped in cross-section and having a radial contact surface ( 13 ) and an axial contact surface ( 14 ) the fixed L-shaped bushings ( 12 ) being mounted to form a cross-sectional U-shape and being locked in an axial direction at both outer sides by an abutment ( 15 , 16 , 24 ), and at least part of the planet gear ( 5 ) is located within the U-shape formed by the fixed L-shaped bushings ( 12 ),
a radial sliding support ( 17 ) arranged in between the radial contact surface ( 13 ) of the fixed L-shaped bushings ( 12 ) and the radial contact surface ( 18 ) of the planet gear ( 5 ),
an axial sliding support ( 19 ) arranged in between the axial contact surface ( 14 ) of the fixed L-shaped bushings ( 12 ) and the axial contact surface ( 20 ) of the planet gears ( 5 ); and

the radial sliding support ( 17 ) c

Assignees

• Zf Wind Power Antwerpen Nv
• Zf Wind Power Antwerpen Nv

Inventors

• Van Den Donker Michiel
• Bogaert Roger
• Leimann Dirk

Classifications

• F16C2361/61

  Toothed gear systems, e.g. support of pinion shafts · CPC title

• F16C33/122

  Multilayer structures of sleeves, washers or liners · CPC title

• F16C17/105

  with at least one bearing surface providing angular contact, e.g. conical or spherical bearing surfaces · CPC title

• F16C17/18

  with floating brasses or brushing, rotatable at a reduced speed {(F16C17/03, F16C17/06 take precedence)} · CPC title

• F16H57/082 Primary

  Planet carriers · CPC title