GB2508949A

GB2508949A - Rotor lock

Info

Publication number: GB2508949A
Application number: GB1311387.3A
Authority: GB
Inventors: Marek Jakubaszek; Massimo Caterini
Original assignee: Romax Technology Ltd
Current assignee: Romax Technology Ltd
Priority date: 2012-12-13
Filing date: 2013-06-26
Publication date: 2014-06-18
Anticipated expiration: 2033-06-26
Also published as: GB2508949B; GB201307730D0; GB201222529D0; GB201311387D0

Abstract

A rotor lock F, for use in a wind turbine installation having a rotor, a housing G and a rotor lock housing 1 for receiving the rotor lock F, has a tubular insert 2 with a front flange, the insert 2 comprising a hard material, such as steel, which is connected to an inside surface of the rotor lock housing 1 for receiving the rotor lock F by an interference fit. It also has a rotor lock F disposed coaxially with the insert 2 and connected to the insert 2. The locking pin 3 is adapted to engage with the rotor to prevent it from rotating. The housing G and rotor lock housing 1 for receiving the rotor lock F are a single cast part having no drilled holes for fixing bolts, and the insert 2 is radially constrained by the interference fit. The rotor lock F may also have a plate 5 to axially constrain the rotor lock.

Description

Rotor lock housing The present invention relates to wind turbine maintenance. More particularly, the present invention relates to an arrangement for a rotor lock housing.

Rotor locks are used in the wind turbine industry and are typically mounted to the turbine's main bearing housing. The rotor lock is needed in order to stop the wind turbine during maintenance: it functions to prevent the rotorfrom turning.

Current approaches for rotor lock housing designs suffer from issues relating to the strength of the arrangement. For example, the rotor lock is typically fastened to the housing by means of bolts, and these cause a stress concentration, generating a notch effect, in the housing.. This means that compact design is preferable, but this leads to difficulties in the manufacturing processes. For example and referring to Figure 1, which shows housing E and rotor lock housing D for attachment of a rotor lock, drilling holes C passing through rotor lock housing D is difficult because of a lack of operating space for a drilling machine, which means that the bolt holes are drilled from the front, but the rotor lock is secured by bolts from the rear. Hence there is the risk to harm the integrity of the rotor lock housing. In addition, using bolts to connect the rotor lock to the housing carries a risk because the load is not a pure tensile load, but includes shear and bending loads. These shortcomings arise when the rotor lock is connected with a housing using bolts.

According to a first aspect of the invention, there is provided a rotor lock housing for a wind turbine installation having a rotor and a housing, the housing having a rotor lock housing (generally embedded as a unique body) for receiving the rotor lock, and a tubular insert comprising a hard material which is connected to an inside surface of the rotor lock housing by an interference fit. Rotor lock is disposed coaxially with the insert and connected to the insert. The locking pin is adapted to engage with the rotor to prevent the rotor from rotating. This means that the housing and rotor lock housing for receiving the rotor lock is a single cast part having no drilled holes for fixing bolts Preferably, the rotor lock housing for receiving the rotor lock includes an annular recess, and the tubular insert comprises a corresponding front flange adapted to engage with the recess. The rotor lock includes a plate having an outer diameter d1, and the plate is connected to a rear annular surface of the tubular insert.

The rotor lock housing for receiving the rotor lock may have a bore diameter d2.This means that the rotor lock is axially constrained by two contact surfaces: one between the rotor lock housing for receiving the rotor lock and the flange, the other between the rotor lock housing for receiving the rotor lock and the plate, because d1 > d2.

Preferably, the hard material comprises steel.

The present invention will now be described, by way of example only, with references to the accompanying drawings, in which: Figure 1 is a view of a prior art of a rotor lock housing for receiving a rotor lock; Figure 2 shows views of the rotor lock housing of the present invention and a sectional view along A-A of the rotor lock housing design; Figure 3 shows detail A of Figure 2; Figure 4 shows load directions during rotor lock operation; and Figure 5 shows an external view of an offshore wind turbine.

Figure 2 shows housing G having rotor lock housing 1 for receiving a rotor lock F comprised of a locking pin 3, piston 4, and plate 5. This is subject to very large loads from a rotor that generates commensurately high stresses between surfaces in contact, for example between rotor lock housing 1 and locking pin 3 in case of no intermediate part usage. To reduce contact stress, insert 2, formed of a hard material such as steel is used as an intermediate part between locking pin 3 and rotor lock housing 1, which increases this contact area. This has three important benefits: 1. Contact area between insert 2 and rotor lock housing 1 is greater than in

prior art designs;

2. Contact forces from locking pin 3 are acting on a hard material having a material strength permitting higher pressures. If localised plasticisation (extension beyond the elastic limit) occurs, it does not have an impact on the functionality of the whole structure because yielded area (due to compression only) will remain consistently limited and localised surrounded by elastic material it won't generate any problem to the structural integrity of rotor lock housing -yielding will be localised and would be limited by the rest of the structure; 3. No bolt holes in rotor lock housing structure.

Figure 2 shows complete assembly of the rotor lock housing of the present invention. This design has as the aim of connecting rotor lock F with rotor lock housing 1 avoiding usage of bolts and taking advantage of steel insert 2 to increase the load capability.

Figure 2 shows a sectional view of the housing G and rotor lock housing 1 integrated as one cast part. Insert 2 is assembled into rotor lock housing 1 via an interference fit. This provides a radial constraint at contact 1. Rotor lock F includes rear plate 5 fixed to insert 2 by bolts 6. As can be seen in Figure 2 and Figure 3, this means that rotor lock F is also axially constrained by two contact surfaces: contact 2, between an axial stop or recess in rotor lock housing 1 and flange 2a on insert 2; and also contact 3 between rotor lock housing 1 and plate 5, in which an outer diameter, d1, of plate 5 is greater than a rotor lock housing 1 bore diameter d2. The recess can be annular.

This means that rotor lock F is prevented from moving axially by the abutment provided by contact 2 at the front and contact 3 at the rear of rotor lock housing 1.

Insert 2 comprises a hard material, such as steel, which has a material strength to allow it to accept higher pressures than cast housing and also if local ised plasticisation occur, it doesn't have a deleterious impact on the functionality of the whole structure.

Figure 4 shows load directions during operation of rotor lock F. Taper angle a of locking pin 3 determines an axial and tangential force component of an applied load (F).

Figure 5 is a perspective view of an example of a wind turbine. Although an offshore wind turbine is shown, it should be noted that the description below may be applicable to other types of wind turbines. The wind turbine 402 includes rotor blades 404 mounted to a rotor or hub 406, which is supported by a nacelle 408 on a tower 410. Wind causes the rotor blades 404 and rotor or hub 406 to rotate about a main axis. A locking pin 3 engages rotor 406 when it is required to prevent the rotation of rotor blades 404.

Claims

Claims 1. A rotor lock housing for a wind turbine installation having a rotor and a housing, the rotor lock housing comprising: a recess; a tubular insert comprising a hard material and connected to an inside surface of the rotor lock housing by an interference fit, the tubular insert further comprising a front flange adapted to engage with the recess; and a rotor lock adapted to connect inside the insert so as to be disposed coaxially when connected, the rotor lock comprising a locking pin adapted to engage with the rotor to prevent the rotor from rotating; in which the rotor lock is connected to the insert and disposed coaxially within the insert, and when engaged with the recess the rotor lock is axially constrained by a contact between the front flange and the recess.
2. A rotor lock housing according to claim 1 or claim 2, in which the rotor lock housing comprises a bore of diameter d2, the rotor lock comprises a plate adapted to connect with the rotor lock housing and having an outer diameter di, greater than d2, the rotor lock is connected to the insert and disposed coaxially within the insert, wherein when the plate is connected to the rotor lock housing the rotor lock is axially constrained by a contact between the plate and the rotor lock housing.
3. A rotor lock housing according to claim 2, in which the plate is connected to a rear surface of the tubular insert.
4. A rotor lock housing according to any of claims 1 to 3, in which the hard material comprises steel.
5. A rotor lock housing according to any preceding claim, in which the rotor lock housing is a single cast part having no drilled holes for fixing bolts for the rotor lock.
6. A rotor lock housing according to any preceding claim, in which the rotor lock housing and the housing form a single cast part.
7. A rotor lock housing substantially as disclosed herein with reference to Figures 2 to 4.
8. A tubular insert for a rotor lock housing according to any preceding claim, the tubular insert comprising a hard material and connected to an inside surface of the rotor lock housing by an interference fit, the tubular insert further comprising a front flange adapted to engage with the recess.
9. A tubular insert for a rotor lock housing substantially as disclosed herein with reference to Figures 2 to 4.
10. A wind turbine installation having a rotor and a housing, in which the housing includes a rotor lock housing for receiving a rotor lock according to any of claims 1 to 7, the rotor lock configured to engage with the rotor to prevent the rotor from rotating.