WO2009048403A1 - Device for changing a blade pitch of a blade in a wind turbine rotor - Google Patents

Device for changing a blade pitch of a blade in a wind turbine rotor Download PDF

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Publication number
WO2009048403A1
WO2009048403A1 PCT/SE2008/000597 SE2008000597W WO2009048403A1 WO 2009048403 A1 WO2009048403 A1 WO 2009048403A1 SE 2008000597 W SE2008000597 W SE 2008000597W WO 2009048403 A1 WO2009048403 A1 WO 2009048403A1
Authority
WO
WIPO (PCT)
Prior art keywords
ring
bearing
gear
gear teeth
blade
Prior art date
Application number
PCT/SE2008/000597
Other languages
French (fr)
Inventor
Torbjörn Lövgren
Pascal Ovize
Giuseppe Garripoli
Original Assignee
Aktiebolaget Skf
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Aktiebolaget Skf filed Critical Aktiebolaget Skf
Publication of WO2009048403A1 publication Critical patent/WO2009048403A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
    • F03D—WIND MOTORS
    • F03D7/00—Controlling wind motors 
    • F03D7/02—Controlling wind motors  the wind motors having rotation axis substantially parallel to the air flow entering the rotor
    • F03D7/022—Adjusting aerodynamic properties of the blades
    • F03D7/0224—Adjusting blade pitch
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2260/00—Function
    • F05B2260/70—Adjusting of angle of incidence or attack of rotating blades
    • F05B2260/79—Bearing, support or actuation arrangements therefor
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/72—Wind turbines with rotation axis in wind direction

Definitions

  • the invention deals with a device for changing a blade pitch of a blade in a wind turbine rotor.
  • the invention deals with a wind turbine rotor including the device according to the first aspect.
  • a device for changing a blade pitch of a blade in a wind turbine rotor comprises a first bearing having a first ring, a second ring, and rolling elements located therebetween.
  • the wind turbine rotor and a blade are being fixable to the first bearing.
  • the first ring is being fixable to the wind turbine rotor using a first fixing means
  • a blade is being fixable to the second ring using a second fixing means.
  • the first ring is being fixable to a blade using a first fixing means
  • the wind turbine rotor is being fixable to the second ring using a second fixing means.
  • a gear is operating between the first ring and of the second ring, wherein the gear comprises a plurality of cog wheels having cogs, whereof a plurality of cogs are in driving cooperative engagement with cogs of at least one other cog wheel in the gear during operation, a motor for driving the gear leading to a rotation of one of the first ring and the second ring leading to changing the blade pitch of the blade.
  • cog is considered synonym to the term tooth in this document.
  • a cog wheel is considered a wheel that has cogs directed outwardly or inwardly, i.e. the cogs extend in an outward radial direction or the cogs extend in an inward radial direction.
  • driving cooperative engagement should be interpreted as cogs that are in contact and a significant driving torque is transmitted between them.
  • two cog wheels that are engaged there may be contact between other cogs adjacent to the cogs having driving cooperative engagement but there is only an insignificant torque, or even no torque, being transferred over the other (adjacent) cogs.
  • driving cooperative engagement is not considered present.
  • the ratio of cogs of a cog wheel that are in driving cooperative engagement as compared to number of cogs that are not in driving cooperative engagement is higher than 5%. In another embodiment, the ratio is higher than 7%. In another embodiment, the ratio is higher than 10%. In another embodiment, the ratio is higher than 15%. In another embodiment, the ratio is higher than 20%. In another embodiment, the ratio is higher than 25%. In another embodiment, the ratio is higher than 30%.
  • the number of cogs that are in driving cooperative engagement is, or is higher than, one 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20.
  • the motor is an electric motor.
  • An advantage of the invention described in the first aspect is that a plurality of cog wheels having cogs, whereof a plurality of cogs are in driving cooperative engagement with cogs of at least one other cog wheel in the gear during operation, which leads to a higher capacity to transmit load/force of the device. This offers an opportunity of developing bigger blades and wind turbines. Also, this offers an opportunity of being able change the blade pitch faster. Also, this leads to less wear of the cogs since a plurality of cogs are involved in creating the cooperating engagement. Alternatively a low torque electrical motor may be used.
  • the gear is a planetary gear, wherein the motor drives a sun wheel of the planetary gear, and the sun wheel drives a plurality of planetary wheels, that drives the one of the first or the second ring .
  • the gear is a type of gear that comprises a wave generator, a flex spline, and a circular spline, wherein the wave generator comprises a bearing and a steel disk, the outer surface of the wave generator plug having an elliptical shape.
  • the flex spline is a thin-walled steel cup with gear teeth into the outer surface near the open end of the cup.
  • the circular spline presents a rigid circular steel ring with teeth on the inside diameter and is located such that its teeth mesh with those of the flex spline. Advantages with this gear include low backlash, high torque, compact size, and excellent positional accuracy.
  • the gear is a type of gear that further comprises a second bearing having a third ring and a fourth ring, and rolling elements located therebetween.
  • a third bearing is having a fifth ring and a sixth ring, and rolling elements located therebetween.
  • the third ring is fixed in relation to the first ring via a third fixing means, and there is an eccenter between the second bearing and the third bearing.
  • the sixth ring is provided with two axially adjacent sections, a first and a second section, of gear teeth, or cogs, along its periphery.
  • the first ring is fixed in relation to a seventh ring via a fourth fixing means, wherein the seventh ring is provided with gear teeth that is interacting with the gear teeth of the sixth ring.
  • the second ring is fixed in relation to an eighth ring via a fifth fixing means, wherein the eighth ring is provided with gear teeth that is interacting with the gear teeth of the sixth ring.
  • a stator and rotor arrangement is acting between the third ring and the fourth ring.
  • the stator and rotor arrangement is responsible for accomplishing a relative movement such that the rotor drives the fourth ring, which leads to an eccentric movement of the sixth ring.
  • This further leads to an interaction between the gear teeth on the sixth ring and the gear teeth on the seventh ring and the gear teeth on the eighth ring.
  • the reduction ratio between the gear teeth on the sixth and seventh respectively sixth and eighth ring is not equal. This leads further to a relative movement between the first ring and the second ring.
  • the eccentric movement of the sixth ring causes the first and second section of the gear teeth to roll off upon the gear teeth of the seventh and eighth ring, and the resulting relative rotational movement between the seventh and the eighth ring are different. At least one gear tooth of each of the first and second section interacts with the gear teeth of the seventh and eighth ring.
  • the roll off movement results in that the gear teeth interacts in multi-turns, instead of only back and forth within a specific interval as for e.g. a pinion gear.
  • the gear according to this embodiment will be subjected to less wear and improved lubrication.
  • the simultaneous interaction between the gear teeth of the first and second section and the gear teeth of the seventh and eighth ring results in that more gear teeth are in engagement at the same time. This design allows high forces and torques, while reducing play and backlash.
  • advantages with this embodiment are high stiffness, a compact and robust design, reduced need for maintenance due to improved lubrication, easy to mount, and low backlash.
  • a first section of the sixth ring is having N-n gear teeth and a second section is having M-m gear teeth, while the seventh ring is being provided with M gear teeth, and the eighth ring is being provided with N gear teeth.
  • a first section of the sixth ring is having N gear teeth and a second section is having M gear teeth, while the seventh ring is being provided with M-m gear teeth, and the eighth ring is being provided with N-n gear teeth.
  • the rotor may drive, e.g. via a second gear, via a connection, e.g. an arm or plate, that will act upon the fourth ring in order to accommodate a movement .
  • the gear is sealed keeping dust out and oil inside.
  • stator winding may be on the third ring, and the rotor winding on the fourth ring. In an embodiment, the stator winding may be on the fourth ring, and the rotor winding on the third ring.
  • a motor may be driving the third or the fourth ring.
  • the motor may be an electric motor.
  • n, m and N may not be trivial.
  • the fourth ring and the fifth ring may be integrally manufactured.
  • the third, fourth or the fifth fixing means may for instance be a stiffening plate, arms, a ring, or a plurality of segments of a ring.
  • the gear further comprises a supporting member fixed to at least one of the first ring, the third ring or the seventh ring. This further improves the rigidity and stiffness of the gear.
  • the gear further comprises a supporting member fixed to at least one of the second ring or the eighth ring. This further improves the rigidity and stiffness of the gear.
  • the supporting member may for instance be a stiffening plate, arms, a ring, or a plurality of segments of a ring.
  • the supporting member is the third and fourth fixing means.
  • the supporting member is the fifth fixing means.
  • the rotor winding is integrated in the fourth or the fifth ring.
  • the rotor winding is integrated in the fourth or the fifth ring.
  • the two axially adjacent sections of N-n and M-m gear teeth may be mounted onto the sixth ring.
  • the two axially adjacent sections of N-n and M-m gear teeth may be forged on the sixth ring .
  • the second or the third bearing is one of a deep groove ball bearing, an angular contact rolling bearing, a self-aligning ball bearing, a cylindrical roller bearing, a spherical roller bearing, a needle roller bearing, a toroidal roller bearing, a slewing bearing, and a taper roller bearing.
  • the first bearing is one of a slewing bearing, a deep groove ball bearing, an angular contact rolling bearing, a self-aligning ball bearing, a cylindrical roller bearing, a spherical roller bearing, a needle roller bearing, a toroidal roller bearing, and a taper roller bearing.
  • the slewing bearing is one of a cross-roller bearing, a four-point contact bearing, a single-row ball bearing, a double-row ball bearing, single-row roller bearing, a double-row roller bearing, a three-row roller bearing, a wire race bearing, or a ball and roller bearing.
  • the turbine rotor is mounted to the first ring and the blade is mounted to the second ring .
  • the turbine rotor is mounted to the second ring and the blade is mounted to the first ring .
  • a wind turbine rotor is disclosed. It comprises a hub mountable to a nacelle of a wind turbine, a plurality of devices according to the first aspect mounted onto the hub, and where each one of the devices according to the first aspect has a blade.
  • Figure 1 A schematic view of a wind turbine rotor.
  • Figure 2 A schematic view of the device according to an embodiment of the invention.
  • Figure 3 A schematic view of a gear of the device according to an embodiment of the invention.
  • Figure 4 A schematic view of a gear of the device according to an embodiment of the invention.
  • Figure 5 A schematic view of a gear of the device according to an embodiment of the invention.
  • FIG 1 a schematic illustration of a wind turbine rotor 1 is given.
  • the turbine rotor 1 is mountable to a nacelle of a wind turbine.
  • FIG 1 there are three blades 2 that are indicated using dashed lines.
  • the device 3 is to be mounted functionally between a blade 2 and the turbine rotor 1.
  • three devices 3 will be needed; one for each blade 2.
  • FIG 2 an embodiment of the device 3 is given.
  • the relation between Figure 2 and Figure 1 is that Figure 2 is a cross section between the turbine rotor 1 and the blade 2.
  • the embodiment includes a device 3 for changing a blade pitch of a blade 2 in a wind turbine rotor 1.
  • the device 3 comprises a first fixing means for fixing the device 3 to a wind turbine rotor 1, a first bearing 4 having a first ring 5, a second ring 6, and rolling elements 7 located therebetween.
  • the first ring 5 is fixable to the wind turbine rotor 1 using a first fixing means.
  • a blade 2 is fixable to the second ring 6 using a second fixing means.
  • the blade 2 is fixed to the wind turbine rotor 1.
  • a gear 8 operates between the first ring 5 and the second ring 6.
  • the gear 8 comprises a plurality of cog wheels having cogs, whereof a plurality of cogs are in driving cooperative engagement with cogs of at least one other cog wheel in the gear 8 during operation.
  • a motor 9 for driving the gear 8 leads to a rotation of the second ring 6 leading to changing the blade pitch of the blade 2.
  • the first ring 5 is the outer ring which is fixed and the second ring 6 is the inner ring which is rotary.
  • the gear 8 is a planetary gear, wherein the motor 9 drives a sun wheel 10 of the planetary gear 8, and the sun wheel 10 drives a plurality of planetary wheels 11 that drives the second ring 6.
  • FIG 4 an embodiment dealing with an alternative gear solution is shown.
  • the gear 8 is constituted by a wave generator 13, a flex spline 16, and a circular spline 6, 19, wherein the wave generator 13 comprises a bearing and a steel disk.
  • the outer surface of the wave generator plug has an elliptical shape.
  • the flex spline 16 is a thin-walled steel cup with gear teeth into the outer surface near the open end of the cup.
  • the circular spline 6, 19 presents a rigid circular steel ring with teeth on the inside diameter and is located such that its teeth mesh with those of the flex spline
  • the wave generator 13 is typically used as the input member, usually attached to a servo motor.
  • the flex spline 16 geometry allows walls of the cup to be radially compliant, yet remain torsionally stiff since the cup has a large diameter. Gear teeth are machined into the outer surface near the open end of the cup (near the "brim").
  • the cup has a rigid boss at one end to provide a rugged mounting surface.
  • the flex spline 16 wall near the brim of the cup conforms to the same elliptical shape of the bearing. This causes the teeth on the outer surface of the flex spline 16 to also conform to this elliptical shape. Accordingly, the flex spline has an elliptical gear pitch diameter on its outer surface.
  • the flex spline 16 is usually the output member of the mechanism.
  • the gear 8 further comprises a second bearing 22 having a third ring 24 and a fourth ring 26, and rolling elements 28 located therebetween.
  • a third bearing 30 has a fifth ring 32 and a sixth ring 34, and rolling elements 36 located therebetween.
  • the third ring 24 is fixed in relation to the first ring 5 via a third fixing means 38, which in this embodiment is a stiffening plate, and an eccenter 40 is located between the second bearing 22 and the third bearing 30.
  • the sixth ring 34 is provided with two axially adjacent sections of gear teeth along its periphery, wherein a first section is having N-n gear teeth 42, and a second section is having M-m gear teeth 44.
  • the first ring 5 is fixed in relation to a seventh ring 46 via a fourth fixing means 47, which in this embodiment is the same as the third fixing means 38.
  • the seventh ring 46 is provided with M gear teeth 48 that interact with the M-m gear teeth 44 of the sixth ring 34.
  • the second ring 6 is fixed in relation to an eighth ring 48 via a fifth fixing means 50, which in this embodiment is a stiffening plate.
  • the eighth ring 49 is provided with N gear teeth 52 that interact with the N-n gear teeth 42 of the sixth ring 34.
  • a stator and rotor arrangement 54 comprising a stator 56 and a rotor 58, acts between the third ring 24 and the fourth ring 26.
  • the stator and rotor arrangement 54 is responsible for accomplishing a relative movement such that the rotor 58 drives the fourth ring 26.
  • This leads to an eccentric movement of the sixth ring 34 which further leads to an interaction between the gear teeth 42, 44 on the sixth ring 34 and the gear teeth 48 on the seventh ring 46 and the gear teeth 52 on the eighth ring 49.
  • the eccentric movement of the sixth ring 34 causes the first and second section of the gear teeth 42, 44 to roll off upon the gear teeth 48, 52 of the seventh 46 and eighth ring 49, and the resulting relative rotational movement between the seventh 46 and the eighth ring 49 are different.
  • At least one gear tooth of each of the first and second section of gear teeth 42, 44 interacts with the gear teeth 48, 52 of the seventh 46 and eighth ring 49.
  • first ring 5 and the second ring 6 which in turn leads to a change of the blade pitch of the blade 2.
  • the rotor winding 58 is integrated in the fourth 26 or the fifth ring 32.
  • the second 22 or the third bearing 30 is one of a deep groove ball bearing, an angular contact rolling bearing, a self-aligning ball bearing, a cylindrical roller bearing, a spherical roller bearing, a needle roller bearing, a toroidal roller bearing, a slewing bearing, or a taper roller bearing.
  • the first bearing 4 is one of a slewing bearing, a deep groove ball bearing, an angular contact rolling bearing, a self-aligning ball bearing, a cylindrical roller bearing, a spherical roller bearing, a needle roller bearing, a toroidal roller bearing, or a taper roller bearing.

Abstract

A device (3) for changing a blade pitch of a blade (2) in a wind turbine rotor (1) is disclosed. It comprises a first bearing (4) having a first ring (5), a second ring (6), and rolling elements (7) located therebetween. The wind turbine rotor (1) and a blade (2) is being fixable to the first bearing (4), and a gear (8) is operating between the first ring (5) and the second ring (6), wherein the gear (8) comprises a plurality of cog wheels (6, 10, 11, 16, 19, 34, 42, 44, 46, 48, 49, 52) having cogs, whereof a plurality of cogs are in driving cooperative engagement with cogs of at least one other cog wheel (6, 10, 11, 16, 19, 34, 42, 44, 46, 48, 49, 52) in the gear (8) during operation, a motor (9) for driving the gear (8) leading to a rotation of one of the first (5) and the second ring (6), leading to changing the blade pitch of the blade (2). Also disclosed is a wind turbine rotor (1) comprising: a hub mountable to a nacelle of a wind turbine, a plurality of devices (3) mounted onto the hub, each one of the devices (3) having a blade (2).

Description

TITLE
Device for changing a blade pitch of a blade in a wind turbine rotor
FIELD OF INVENTION
According to a first aspect of the present invention, the invention deals with a device for changing a blade pitch of a blade in a wind turbine rotor. According to a second aspect of the present invention, the invention deals with a wind turbine rotor including the device according to the first aspect.
SUMMARY OF INVENTION
According to the first aspect, a device for changing a blade pitch of a blade in a wind turbine rotor is disclosed. It comprises a first bearing having a first ring, a second ring, and rolling elements located therebetween. The wind turbine rotor and a blade are being fixable to the first bearing. In an embodiment, the first ring is being fixable to the wind turbine rotor using a first fixing means, and a blade is being fixable to the second ring using a second fixing means. In an embodiment, the first ring is being fixable to a blade using a first fixing means, and the wind turbine rotor is being fixable to the second ring using a second fixing means. A gear is operating between the first ring and of the second ring, wherein the gear comprises a plurality of cog wheels having cogs, whereof a plurality of cogs are in driving cooperative engagement with cogs of at least one other cog wheel in the gear during operation, a motor for driving the gear leading to a rotation of one of the first ring and the second ring leading to changing the blade pitch of the blade. The term cog is considered synonym to the term tooth in this document. Also, a cog wheel is considered a wheel that has cogs directed outwardly or inwardly, i.e. the cogs extend in an outward radial direction or the cogs extend in an inward radial direction.
The term driving cooperative engagement should be interpreted as cogs that are in contact and a significant driving torque is transmitted between them. As an illustrative example, if two cog wheels that are engaged there may be contact between other cogs adjacent to the cogs having driving cooperative engagement but there is only an insignificant torque, or even no torque, being transferred over the other (adjacent) cogs. In this example, driving cooperative engagement is not considered present.
In an embodiment, the ratio of cogs of a cog wheel that are in driving cooperative engagement as compared to number of cogs that are not in driving cooperative engagement is higher than 5%. In another embodiment, the ratio is higher than 7%. In another embodiment, the ratio is higher than 10%. In another embodiment, the ratio is higher than 15%. In another embodiment, the ratio is higher than 20%. In another embodiment, the ratio is higher than 25%. In another embodiment, the ratio is higher than 30%.
In an embodiment, the number of cogs that are in driving cooperative engagement is, or is higher than, one 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20.
In an embodiment, the motor is an electric motor. An advantage of the invention described in the first aspect is that a plurality of cog wheels having cogs, whereof a plurality of cogs are in driving cooperative engagement with cogs of at least one other cog wheel in the gear during operation, which leads to a higher capacity to transmit load/force of the device. This offers an opportunity of developing bigger blades and wind turbines. Also, this offers an opportunity of being able change the blade pitch faster. Also, this leads to less wear of the cogs since a plurality of cogs are involved in creating the cooperating engagement. Alternatively a low torque electrical motor may be used. In an embodiment, the gear is a planetary gear, wherein the motor drives a sun wheel of the planetary gear, and the sun wheel drives a plurality of planetary wheels, that drives the one of the first or the second ring . In an embodiment, the gear is a type of gear that comprises a wave generator, a flex spline, and a circular spline, wherein the wave generator comprises a bearing and a steel disk, the outer surface of the wave generator plug having an elliptical shape. The flex spline is a thin-walled steel cup with gear teeth into the outer surface near the open end of the cup. The circular spline presents a rigid circular steel ring with teeth on the inside diameter and is located such that its teeth mesh with those of the flex spline. Advantages with this gear include low backlash, high torque, compact size, and excellent positional accuracy.
In an embodiment, the gear is a type of gear that further comprises a second bearing having a third ring and a fourth ring, and rolling elements located therebetween. A third bearing is having a fifth ring and a sixth ring, and rolling elements located therebetween. The third ring is fixed in relation to the first ring via a third fixing means, and there is an eccenter between the second bearing and the third bearing. The sixth ring is provided with two axially adjacent sections, a first and a second section, of gear teeth, or cogs, along its periphery. The first ring is fixed in relation to a seventh ring via a fourth fixing means, wherein the seventh ring is provided with gear teeth that is interacting with the gear teeth of the sixth ring. The second ring is fixed in relation to an eighth ring via a fifth fixing means, wherein the eighth ring is provided with gear teeth that is interacting with the gear teeth of the sixth ring. A stator and rotor arrangement is acting between the third ring and the fourth ring. The stator and rotor arrangement is responsible for accomplishing a relative movement such that the rotor drives the fourth ring, which leads to an eccentric movement of the sixth ring. This further leads to an interaction between the gear teeth on the sixth ring and the gear teeth on the seventh ring and the gear teeth on the eighth ring. The reduction ratio between the gear teeth on the sixth and seventh respectively sixth and eighth ring is not equal. This leads further to a relative movement between the first ring and the second ring. The eccentric movement of the sixth ring causes the first and second section of the gear teeth to roll off upon the gear teeth of the seventh and eighth ring, and the resulting relative rotational movement between the seventh and the eighth ring are different. At least one gear tooth of each of the first and second section interacts with the gear teeth of the seventh and eighth ring. The roll off movement results in that the gear teeth interacts in multi-turns, instead of only back and forth within a specific interval as for e.g. a pinion gear. As a consequence, the gear according to this embodiment will be subjected to less wear and improved lubrication. The simultaneous interaction between the gear teeth of the first and second section and the gear teeth of the seventh and eighth ring results in that more gear teeth are in engagement at the same time. This design allows high forces and torques, while reducing play and backlash.
Consequently, advantages with this embodiment are high stiffness, a compact and robust design, reduced need for maintenance due to improved lubrication, easy to mount, and low backlash.
In an embodiment, a first section of the sixth ring is having N-n gear teeth and a second section is having M-m gear teeth, while the seventh ring is being provided with M gear teeth, and the eighth ring is being provided with N gear teeth.
In an embodiment, a first section of the sixth ring is having N gear teeth and a second section is having M gear teeth, while the seventh ring is being provided with M-m gear teeth, and the eighth ring is being provided with N-n gear teeth.
In an embodiment, the rotor may drive, e.g. via a second gear, via a connection, e.g. an arm or plate, that will act upon the fourth ring in order to accommodate a movement .
In an embodiment, the gear is sealed keeping dust out and oil inside.
In an embodiment, the stator winding may be on the third ring, and the rotor winding on the fourth ring. In an embodiment, the stator winding may be on the fourth ring, and the rotor winding on the third ring.
In an embodiment, a motor may be driving the third or the fourth ring. In an embodiment, the motor may be an electric motor.
It should be noted that the relation between n, m and N may not be trivial. A few steps indicating a process towards finding suitable relations include a) determination of desired gear ratio, b) determination of desired value of the tooth module (m) where the module=the ratio of the pitch diameter to the number of teeth, c) determining of approximate pitch diameter for the fixed gear wheel, d) calculation of the number of teeth and determination of the pitch diameter of the fixed wheel and of the eccentric wheel starting from the initial values in steps a) , b) and c) , e) drawing the teeth of the two gear wheels on a common sheet of drawing paper with guidance from the raw data for the values obtained in step d) , f) visual inspection of the drawn gear wheels for determining the areas on the wheels where the teeth interfere with each other, g) graphic determination of the profile shift and stubbing, whereby the basic eccentricity eo is changed to a new value eo - x.m where m is the module, h) drawing the teeth of the two wheels corrected according to g) , and possible residual correction of the eccentricity by a factor s, so that at all places round the wheels where the teeth are not in mesh, the top lands of respective teeth will have a predetermined minimum clearance, whereby the total eccentricity will be etot =eo +x.m-s.
In an embodiment, the fourth ring and the fifth ring may be integrally manufactured. In an embodiment, the third, fourth or the fifth fixing means may for instance be a stiffening plate, arms, a ring, or a plurality of segments of a ring.
In an embodiment, the gear further comprises a supporting member fixed to at least one of the first ring, the third ring or the seventh ring. This further improves the rigidity and stiffness of the gear.
In an embodiment, the gear further comprises a supporting member fixed to at least one of the second ring or the eighth ring. This further improves the rigidity and stiffness of the gear.
In an embodiment, the supporting member may for instance be a stiffening plate, arms, a ring, or a plurality of segments of a ring. In an embodiment, the supporting member is the third and fourth fixing means. By this arrangement, the gear may be even more compact with maintained high stiffness.
In an embodiment, the supporting member is the fifth fixing means. By this arrangement, the gear may be even more compact with maintained high stiffness.
In an embodiment, the rotor winding is integrated in the fourth or the fifth ring.
In an embodiment, the rotor winding is integrated in the fourth or the fifth ring. In an embodiment, the two axially adjacent sections of N-n and M-m gear teeth may be mounted onto the sixth ring. In an embodiment, the two axially adjacent sections of N-n and M-m gear teeth may be forged on the sixth ring . In an embodiment, the second or the third bearing is one of a deep groove ball bearing, an angular contact rolling bearing, a self-aligning ball bearing, a cylindrical roller bearing, a spherical roller bearing, a needle roller bearing, a toroidal roller bearing, a slewing bearing, and a taper roller bearing.
In an embodiment, the first bearing is one of a slewing bearing, a deep groove ball bearing, an angular contact rolling bearing, a self-aligning ball bearing, a cylindrical roller bearing, a spherical roller bearing, a needle roller bearing, a toroidal roller bearing, and a taper roller bearing.
In an embodiment, the slewing bearing is one of a cross-roller bearing, a four-point contact bearing, a single-row ball bearing, a double-row ball bearing, single-row roller bearing, a double-row roller bearing, a three-row roller bearing, a wire race bearing, or a ball and roller bearing.
In an embodiment, the turbine rotor is mounted to the first ring and the blade is mounted to the second ring .
In an embodiment, the turbine rotor is mounted to the second ring and the blade is mounted to the first ring . According to the second aspect, a wind turbine rotor is disclosed. It comprises a hub mountable to a nacelle of a wind turbine, a plurality of devices according to the first aspect mounted onto the hub, and where each one of the devices according to the first aspect has a blade. BRIEF DESCRIPTION OF DRAWINGS
Figure 1: A schematic view of a wind turbine rotor.
Figure 2: A schematic view of the device according to an embodiment of the invention. Figure 3: A schematic view of a gear of the device according to an embodiment of the invention.
Figure 4 : A schematic view of a gear of the device according to an embodiment of the invention.
Figure 5: A schematic view of a gear of the device according to an embodiment of the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
In Figure 1 a schematic illustration of a wind turbine rotor 1 is given. The turbine rotor 1 is mountable to a nacelle of a wind turbine. In Figure 1 there are three blades 2 that are indicated using dashed lines. The device 3 is to be mounted functionally between a blade 2 and the turbine rotor 1. Thus, in view of the turbine rotor 1 as depicted in Figure 1, three devices 3 will be needed; one for each blade 2.
In Figure 2, an embodiment of the device 3 is given. The relation between Figure 2 and Figure 1 is that Figure 2 is a cross section between the turbine rotor 1 and the blade 2. The embodiment includes a device 3 for changing a blade pitch of a blade 2 in a wind turbine rotor 1. The device 3 comprises a first fixing means for fixing the device 3 to a wind turbine rotor 1, a first bearing 4 having a first ring 5, a second ring 6, and rolling elements 7 located therebetween. The first ring 5 is fixable to the wind turbine rotor 1 using a first fixing means. A blade 2 is fixable to the second ring 6 using a second fixing means. In an embodiment the blade 2 is fixed to the wind turbine rotor 1. A gear 8 operates between the first ring 5 and the second ring 6. The gear 8 comprises a plurality of cog wheels having cogs, whereof a plurality of cogs are in driving cooperative engagement with cogs of at least one other cog wheel in the gear 8 during operation. A motor 9 for driving the gear 8 leads to a rotation of the second ring 6 leading to changing the blade pitch of the blade 2. In Figure 1, the first ring 5 is the outer ring which is fixed and the second ring 6 is the inner ring which is rotary. In an embodiment of the gear, as shown in Figure 3 the gear 8 is a planetary gear, wherein the motor 9 drives a sun wheel 10 of the planetary gear 8, and the sun wheel 10 drives a plurality of planetary wheels 11 that drives the second ring 6. In figure 4, an embodiment dealing with an alternative gear solution is shown. The gear 8 is constituted by a wave generator 13, a flex spline 16, and a circular spline 6, 19, wherein the wave generator 13 comprises a bearing and a steel disk. The outer surface of the wave generator plug has an elliptical shape. The flex spline 16 is a thin-walled steel cup with gear teeth into the outer surface near the open end of the cup. The circular spline 6, 19 presents a rigid circular steel ring with teeth on the inside diameter and is located such that its teeth mesh with those of the flex spline
16. The wave generator 13 is typically used as the input member, usually attached to a servo motor. The flex spline 16 geometry allows walls of the cup to be radially compliant, yet remain torsionally stiff since the cup has a large diameter. Gear teeth are machined into the outer surface near the open end of the cup (near the "brim"). The cup has a rigid boss at one end to provide a rugged mounting surface. The flex spline 16 wall near the brim of the cup conforms to the same elliptical shape of the bearing. This causes the teeth on the outer surface of the flex spline 16 to also conform to this elliptical shape. Accordingly, the flex spline has an elliptical gear pitch diameter on its outer surface. The flex spline 16 is usually the output member of the mechanism.
In figure 5, an embodiment dealing with an alternative gear solution is shown. The gear 8 further comprises a second bearing 22 having a third ring 24 and a fourth ring 26, and rolling elements 28 located therebetween. A third bearing 30 has a fifth ring 32 and a sixth ring 34, and rolling elements 36 located therebetween. The third ring 24 is fixed in relation to the first ring 5 via a third fixing means 38, which in this embodiment is a stiffening plate, and an eccenter 40 is located between the second bearing 22 and the third bearing 30. The sixth ring 34 is provided with two axially adjacent sections of gear teeth along its periphery, wherein a first section is having N-n gear teeth 42, and a second section is having M-m gear teeth 44. The first ring 5 is fixed in relation to a seventh ring 46 via a fourth fixing means 47, which in this embodiment is the same as the third fixing means 38. The seventh ring 46 is provided with M gear teeth 48 that interact with the M-m gear teeth 44 of the sixth ring 34. The second ring 6 is fixed in relation to an eighth ring 48 via a fifth fixing means 50, which in this embodiment is a stiffening plate. The eighth ring 49 is provided with N gear teeth 52 that interact with the N-n gear teeth 42 of the sixth ring 34. A stator and rotor arrangement 54, comprising a stator 56 and a rotor 58, acts between the third ring 24 and the fourth ring 26. The stator and rotor arrangement 54 is responsible for accomplishing a relative movement such that the rotor 58 drives the fourth ring 26. This leads to an eccentric movement of the sixth ring 34, which further leads to an interaction between the gear teeth 42, 44 on the sixth ring 34 and the gear teeth 48 on the seventh ring 46 and the gear teeth 52 on the eighth ring 49. The eccentric movement of the sixth ring 34 causes the first and second section of the gear teeth 42, 44 to roll off upon the gear teeth 48, 52 of the seventh 46 and eighth ring 49, and the resulting relative rotational movement between the seventh 46 and the eighth ring 49 are different. At least one gear tooth of each of the first and second section of gear teeth 42, 44 interacts with the gear teeth 48, 52 of the seventh 46 and eighth ring 49. This leads to a relative movement between the first ring 5 and the second ring 6, which in turn leads to a change of the blade pitch of the blade 2. It may be preferred to make two rings integral at manufacture, i.e. instead of forging two rings, one single ring is forged to have two raceways, e.g. raceways on opposite sides. In an embodiment, the rotor winding 58 is integrated in the fourth 26 or the fifth ring 32. In an embodiment, the second 22 or the third bearing 30 is one of a deep groove ball bearing, an angular contact rolling bearing, a self-aligning ball bearing, a cylindrical roller bearing, a spherical roller bearing, a needle roller bearing, a toroidal roller bearing, a slewing bearing, or a taper roller bearing. In an embodiment, the first bearing 4 is one of a slewing bearing, a deep groove ball bearing, an angular contact rolling bearing, a self-aligning ball bearing, a cylindrical roller bearing, a spherical roller bearing, a needle roller bearing, a toroidal roller bearing, or a taper roller bearing.

Claims

PATENT CLAIMS
1. Device (3) for changing a blade pitch of a blade (2) in a wind turbine rotor (1), comprising: -a first bearing (4) having a first ring (5), a second ring (6), and rolling elements (7) located therebetween, -the wind turbine rotor (1) and a blade (2) being fixable to the first bearing (4),
-a gear (8) operating between the first ring (5) and the second ring ( 6) , -wherein the gear (8) comprises a plurality of cog wheels (6, 10, 11, 16, 19, 34, 42, 44, 46, 48, 49, 52) having cogs, whereof a plurality of cogs are in driving cooperative engagement with cogs of at least one other cog wheel (6, 10, 11, 16, 19, 34, 42, 44, 46, 48, 49, 52) in the gear during operation,
- a motor (9, 54) for driving the gear (8) leading to a rotation of one of the first (5) and the second ring (6), leading to changing the blade pitch of the blade (2).
2. Device (3) according to claim 1, wherein the gear (8) is a planetary gear, wherein the motor (9) drives a sun wheel (10) of the planetary gear and the sun wheel (10) drives a plurality of planetary wheels (11) that drives one of the first (5) and the second ring (6) .
3. Device (3) according to claim 1, wherein the gear (8) further comprises:
- a wave generator (13), a flex spline (16), and a circular spline (19), wherein the wave generator (13) comprises a bearing and a steel disk, the outer surface of the wave generator plug having an elliptical shape,
- the flex spline (16) is a thin-walled steel cup with gear teeth into the outer surface near the open end of the cup,
-the circular spline (19) presents a rigid circular steel ring with teeth on the inside diameter and is located such that its teeth mesh with those of the flex spline ( 16) .
4. Device (3) according to claim 1, wherein the gear (8) further comprises a second bearing (22) having a third ring (24) and a fourth ring (26), and rolling elements (28) located therebetween, -a third bearing (30) having a fifth ring (32) and a sixth ring (34), and rolling elements (36) located therebetween,
-the third ring (24) being fixed in relation to the first ring (5) via a third fixing means (38), -an eccenter (40) between the second bearing (22) and the third bearing (30),
-the sixth ring (34) being provided with two axially adjacent sections of gear teeth (42, 44) along its periphery, -the first ring (5) being fixed in relation to a seventh ring (46) via a fourth fixing means (47), wherein the seventh ring (46) is provided with gear teeth (48), interacting with the gear teeth (44) of the sixth ring (34 ), -the second ring (6) being fixed in relation to an eighth ring (49) via a fifth fixing means (50), wherein the eighth ring (49) is provided with gear teeth (52), interacting with the gear teeth (42) of the sixth ring (34),
-wherein the numbers of gear teeth (42, 44, 48, 52) on the sixth ring (34), the seventh ring (46), and the eighth ring (49) are different, such that the reduction ratio between the gear teeth (44, 48) on the sixth ring (34) and the seventh ring (46) is different than the reduction ratio between the gear teeth (42, 52) on the sixth ring (34) and the eighth ring (49),
-a stator and rotor arrangement (54) acting between the third ring (24) and the fourth ring (26), the stator and rotor arrangement (54) being responsible for accomplishing a relative movement such that the rotor (58) drives the fourth ring (26), leading to an eccentric movement of the sixth ring (34), leading to an interaction between the gear teeth
(42, 44) on the sixth ring (34) and the gear teeth (30) on the seventh ring (46) and the gear teeth (52) on the eighth ring (49), leading to a relative movement between the first ring (5) and the second ring ( 6) .
5. Device (3) according to claim 4, wherein a first section of the sixth ring (34) is having N-n gear teeth (42) and a second section is having M-m gear teeth (44), the seventh ring (46) being provided with M gear teeth
(48), and the eighth ring (49) being provided with N gear teeth (52) .
6. Device (3) according to claim 4, wherein a first section of the sixth ring (34) is having N gear teeth (42) and a second section is having M gear teeth (44), the seventh ring (46) being provided with M-m gear teeth (48), and the eighth ring (49) being provided with N-n gear teeth (52) .
7. Device (3) according to claim 4, further comprising a supporting member fixed to at least one of the first ring
(5), the third ring (24) or the seventh ring (46).
8. Device (3) according to claim 4, further comprising a supporting member fixed to at least one of the second ring (6) or the eighth ring (49).
9. Device (3) according to claim 4, wherein the rotor (58) is integrated in the fourth (26) or the fifth ring (32) .
10. Device (3) according to claim 4, wherein the second (22) or the third bearing (30) is one of a deep groove ball bearing, an angular contact rolling bearing, a self- aligning ball bearing, a cylindrical roller bearing, a spherical roller bearing, a needle roller bearing, a toroidal roller bearing, a slewing bearing, or a taper roller bearing.
11. Device (3) according to claim 4, wherein the first bearing (4) is one of a slewing bearing, a deep groove ball bearing, an angular contact rolling bearing, a self- aligning ball bearing, a cylindrical roller bearing, a spherical roller bearing, a needle roller bearing, a toroidal roller bearing, or a taper roller bearing.
12. Device (3) according to claim 4, wherein the fourth ring (26) and the fifth ring (32) may be integrally manufactured.
13. A wind turbine rotor (1) comprising:
-a hub mountable to a nacelle of a wind turbine,
-a plurality of devices (3) according to claim 1 mounted onto the hub,
-each one of the devices (3) according to claim 1 having a blade (2) .
PCT/SE2008/000597 2007-10-11 2008-10-13 Device for changing a blade pitch of a blade in a wind turbine rotor WO2009048403A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
SE0702294 2007-10-11
SE0702294-0 2007-10-11
SE0800453-3 2008-02-26
SE0800453 2008-02-26

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Publication Number Publication Date
WO2009048403A1 true WO2009048403A1 (en) 2009-04-16

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ITBO20090414A1 (en) * 2009-06-25 2010-12-26 Bonfiglioli Riduttori Spa GROUP FOR COMMANDING THE WINDLESS ORIENTATION OF A WIND GENERATOR
CN102900608A (en) * 2012-10-25 2013-01-30 国电联合动力技术有限公司 Multipoint meshing type pitch-variable driving device and wind generating set adopting device
WO2013091664A1 (en) * 2011-12-20 2013-06-27 Imo Holding Gmbh Blade bearing or nacelle bearing of a wind turbine
EP3364018A4 (en) * 2015-10-14 2019-06-12 Nabtesco Corporation Assembly of blade and rotor, and power generation device
EP3364019A4 (en) * 2015-10-14 2019-06-12 Nabtesco Corporation Assembly of blade and rotor, and power generation device
US10655610B2 (en) 2017-04-28 2020-05-19 General Electric Company Wire races for wind turbine bearings
CN112253385A (en) * 2020-09-15 2021-01-22 东方电气风电有限公司 Novel variable-pitch driving structure of wind generating set

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EP1553315A1 (en) * 2004-01-07 2005-07-13 Ntn Corporation Cylindrical roller bearing and planetary gear assembly utilizing the same
EP1596064A2 (en) * 2004-05-11 2005-11-16 REpower Systems AG Blade pitch adjustment system for wind turbine
WO2007098759A2 (en) * 2006-02-28 2007-09-07 Vestas Wind Systems A/S A wind turbine rotor, a rotation controlling mechanism and a method for controlling at least one blade of a wind turbine rotor

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US3996816A (en) * 1974-08-01 1976-12-14 The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland Harmonic drives
EP0266972A2 (en) * 1986-11-05 1988-05-11 Harmonic Drive Systems Inc. Tooth profile of spline of strain wave gearing
WO2005019642A1 (en) * 2003-08-21 2005-03-03 General Electric Company Wind turbine blade pitch change by means of electric stepping motor
EP1553315A1 (en) * 2004-01-07 2005-07-13 Ntn Corporation Cylindrical roller bearing and planetary gear assembly utilizing the same
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ITBO20090414A1 (en) * 2009-06-25 2010-12-26 Bonfiglioli Riduttori Spa GROUP FOR COMMANDING THE WINDLESS ORIENTATION OF A WIND GENERATOR
WO2013091664A1 (en) * 2011-12-20 2013-06-27 Imo Holding Gmbh Blade bearing or nacelle bearing of a wind turbine
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CN102900608A (en) * 2012-10-25 2013-01-30 国电联合动力技术有限公司 Multipoint meshing type pitch-variable driving device and wind generating set adopting device
EP3364018A4 (en) * 2015-10-14 2019-06-12 Nabtesco Corporation Assembly of blade and rotor, and power generation device
EP3364019A4 (en) * 2015-10-14 2019-06-12 Nabtesco Corporation Assembly of blade and rotor, and power generation device
US10655610B2 (en) 2017-04-28 2020-05-19 General Electric Company Wire races for wind turbine bearings
CN112253385A (en) * 2020-09-15 2021-01-22 东方电气风电有限公司 Novel variable-pitch driving structure of wind generating set

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