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

• US 9,416,867 B2
• Filed: 04/09/2013
• Issued: 08/16/2016
• Est. Priority Date: 05/08/2012
• Status: Active Grant

• Current Assignee: Zf Wind Power Antwerpen N.V. (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Zf Wind Power Antwerpen N.V. (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Van Den Donker, Michiel, Bogaert, Roger, Leimann, Dirk
• Primary Examiner(s): Hansen, Colby M
• Application Number:
  US14/398,132
• Publication Number:
  US 20150133260A1
• Time in Patent Office: 1,225 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: F03D 15/00 Transmission of mechanical power
• CPC Class Codes: F03D 15/10 using gearing not limited to rotary motion, e.g. with oscillating or reciprocating members
• CPC Class Codes: F03D 80/70 Bearing or lubricating arrangements
• CPC Class Codes: F16C 17/105 with at least one bearing surface providing angular contact, e.g. conical or spherical bearing surfaces
• CPC Class Codes: F16C 17/107 with at least one surface for radial load and at least one surface for axial load
• CPC Class Codes: F16C 17/18 with floating brasses or brushing, rotatable at a reduced speed F16C17/03, F16C17/06 take precedence
• CPC Class Codes: F16C 17/26 Systems consisting of a plurality of sliding-contact bearings
• CPC Class Codes: F16C 2360/31 Wind motors in general F03D
• CPC Class Codes: F16C 2361/61 Toothed gear systems, e.g. support of pinion shafts in general F16H57/02
• CPC Class Codes: F16C 33/122 Multilayer structures of sleeves, washers or liners
• CPC Class Codes: F16H 2057/085 Bearings for orbital gears
• CPC Class Codes: F16H 37/041 for conveying rotary motion with constant gear ratio
• CPC Class Codes: F16H 57/082 Planet carriers
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction

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.

Claims

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) comprises at least one free-rotating bushing (17).

22. The planetary gear stage (2) according to claim 21, wherein the at least one free-rotating bushing (17) is formed of a plain bearing material.

23. The planetary gear stage (2) according to claim 21, wherein the at least one free-rotating bushing (17) is formed of either steel or steel coated with a plain bearing material.