WIND TURBINE GEAR UNIT WITH INTEGRATED ROTOR BEARING
(19)AUSTRALIAN PATENT OFFICE(54) Title WIND TURBINE GEAR UNIT WITH INTEGRA I bD ROTOR BEARING(21) Application No: 2003290384 (22) Application Date: 2003.11.18(87) WIPONo: WO04/046582 (30) Priority Data (31) Number (32) Date 0226940.5 2002.11.19 (33) Country GB(43) Publication Date : 2004.06.15(43) Publication Journal Date : 2004.07.15(71) Applicant(s) HANSEN TRANSMISSIONS INTERNATIONAL NV(72) Inventor(s) FLAMANG, Peter; SMOOK, Warren;BOGAERT, Roger (H) Application NoAU2003290384 A1(19)AUSTRALIAN PATENT OFFICE(54) Title WIND TURBINE GEAR UNIT WITH INTEGRA I bD ROTOR BEARING(21) Application No: 2003290384 (22) Application Date: 2003.11.18(87) WIPONo: WO04/046582 (30) Priority Data (31) Number (32) Date 0226940.5 2002.11.19 (33) Country GB(43) Publication Date : 2004.06.15(43) Publication Journal Date : 2004.07.15(71) Applicant(s) HANSEN TRANSMISSIONS INTERNATIONAL NV(72) Inventor(s) FLAMANG, Peter; SMOOK, Warren;BOGAERT, Roger In a gear unit for use in wind turbines and of the kind with a planetary gear stage, and an integrated main rotor bearing that is adapted to provide location for the rotor hub relative to the wind turbine nacelle and to locate the planet carrier relative to a low speed ring gear, the forces due to bending moments acting between the rotor hub and nacelle are transmitted substantially directly from the rotor hub to the nacelle via the main bearing and substantially none of the bending moments are transmitted to the nacelle via the ring gear of the planetary gear stage. A gear unit for use in wind turbines of the kind having an integrated main rotor bearing (4) and comprising a planetary gear stage,
said integrated main rotor bearing (4) being adapted to provide location for the rotor hub (2) relative to the wind turbine nacelle (1) and to locate the planet carrier (3) relative to a low speed ring gear (13), characterised in that
the planet gears (36) lie axially displaced relative to the main bearing (4) as considered in the direction of the axis about which the planet carrier (3) rotates, whereby
the ring gear (13) of the planetary stage is selectively releasably secured to the nacelle (1) via an intermediate housing structure (11),
which intermediate housing structure (11) is secured directly to the nacelle (1) or to the outer ring (5) of the main bearing (4), whereby
forces due to bending moments acting between the rotor hub (2) and nacelle (1) are transmitted substantially directly from the rotor hub (2) to the nacelle (1) via the main bearing (4) and substantially none of said bending moments are transmitted to the nacelle (1) via the ring gear (13) of the planetary gear stage, so that all parts of the gear unit except for the main bearing and at least a part (33) of the planet carrier (3) can be dismounted without removing the rotor. A gear unit according to claim 1 wherein the or each outer ring (5) of the main rotor bearing (4) is secured directly to the nacelle (1) or optionally via a main bearing cover or an intermediate housing structure, and the rotor hub (2) and planet carrier (3) are secured to the inner ring(s) (6) of the main bearing (4). A gear unit according to claim 1 or claim 2 wherein no part of the planet carrier (3) which is substantially in the same axial plane as a plane containing the planet gears (35) transmits any said bending moments to the nacelle (1). A gear unit according to any one of the preceding claims wherein said main bearing (4) is a double taper roller bearing. A gear unit according to claim 4 wherein said double taper roller bearing (4) comprises two series of taper rollers arranged in an O configuration. A gear unit according to claim 4 or claim 5 wherein said double taper roller bearing (4) comprises a split inner ring. A gear unit according to any one of the preceding claims wherein the outer ring(s) (5) of the main bearing (4) is secured substantially directly to the nacelle (1) via a main bearing cover (9). A gear unit according to any one of claims 1 to 6 wherein the main bearing (4) is secured substantially directly to the nacelle (1) via an intermediate housing (11). A gear unit according to claim 8 wherein said intermediate housing (11) is secured directly to the nacelle (1) or to the outer ring (5) of the main bearing (4). A gear unit according to any one of the preceding claims wherein the ring gear (13) of the planetary gear stage is selectively releasably secured to the nacelle (1) whereby at least the planet gears (36) and ring gear (13) may be dismounted without the need to remove the rotor. A gear unit according to claim 10 wherein all parts of the gear unit except at least one of the main bearing (4) and the planet carrier (3) or a part thereof may be dismounted without the need to remove the rotor. A gear unit according to claims 10 or claim 11 wherein the planet carrier (3) is of a two part construction comprising one part to support the planet gears (36), said one part being selectively releasably secured to a second part of the planet carrier (3) which is secured substantially directly relative to the main bearing (4). A gear unit according to any one of the preceding claims wherein the main bearing (4) is provided with a seal pack (15) arranged to be selectively removable in situ from the main bearing (4). A gear unit according to claim 13 wherein said seal pack (15) is displaceable axially relative to the main bearing (4). A gear unit according to claim 13 or claim 14 wherein said seal pack (15) comprises a circumferentially discontinuous seal.