Transmission for a wind turbine

Abstract

A transmission particularly for use in wind turbine applications but may also be used in other applications. The transmission includes a fixed ring gear and a first drive member rotatably supported within the fixed ring gear, the first drive member defining a plurality of radially arranged apertures or bores, each of the apertures or bores receiving a tooth element. The first drive member comprises a tooth element having a tooth tip and a tooth base, and the first drive member further comprises a radially outer surface and a radially inner surface, and wherein the tooth tip of the tooth element engages a respective gear profile defined by the fixed ring gear. The second drive member is rotatably supported such that it extends within the first drive member and defines a cam profile that engages the tooth base of each of the plurality of tooth elements. The first drive member further includes a lubrication system configured to supply a lubrication fluid to at least one of: i) radially arranged orifices; ii) a radially outer surface of the first drive member; and iii) a radially inner surface of the first drive member. Beneficially, the present invention relates to lubricating a target point on and in a first drive member by defining a lubrication channel inside the first drive member. Constructing the first drive member in this way provides a convenient and mechanically simple way to supply lubricating oil directly to the components where it is most required.

Description

Technical Field

[0001] The invention relates to a transmission in a powertrain, in particular a transmission for a wind turbine. Background Art

[0002] Wind turbines use a large rotor with multiple rotor blades to convert wind energy into electrical energy. A typical horizontal axis wind turbine (HAWT) includes a tower, a nacelle on top of the tower, a rotor hub mounted to the nacelle, and multiple wind turbine rotor blades coupled to the rotor hub. Depending on the wind direction, the nacelle and rotor blades are steered by a yaw system for rotating the nacelle and a pitch system for rotating the blades, and are directed to the optimal direction.

[0003] The nacelle houses many of the functional components of the wind turbine, including, for example, the main rotor shaft and one or more generators and converter equipment for converting mechanical energy at the rotor into electrical energy for supply to the grid. In some types of wind turbines (referred to as "direct drive" systems), the main rotor shaft directly drives the generator. However, it is more common for wind turbines to include a gearbox to increase the rotational speed between the main rotor shaft and the generator, thereby converting the low speed but high torque input from the main rotor shaft into a low torque but high speed input in the generator. The main rotor shaft, gearbox, and generator together form the power train of the wind turbine.

[0004] Typically, gearboxes for wind turbines include shunt gearboxes, epicyclic gearboxes, or a combination of both, and provide a transmission ratio between 1:30 and 1:140. Such high transmission ratios typically require multiple gear stages, which increases the size of the gearbox and also increases its overall mass and cost. The mass of the gearbox has a significant impact on the overall mass of the nacelle, and it is desirable to reduce this mass in order to reduce the swinging effect of the nacelle mass on top of the wind turbine tower, which may be more than 100 meters in height, and even up to 160 meters or more.

[0005] Gear system designs with more compact layouts are known. One such gear system is known as a strain wave drive system or "harmonic drive" and is well known in small-scale applications such as robotic joints and wheel motors. However, such systems are used as speed reducers and are not generally considered compatible with speed increasers due to issues with torque loads.

[0006] Another type of compact gear system is disclosed in US8656809B2 and US8256327B2 of the Wittenstein Group. This gear system includes a reducer device characterized by a plurality of circumferentially arranged teeth, each of which is configured to move radially in a rack member. The base of the tooth is driven by a rotatable cam member constituting an input drive, while the tip of the tooth engages an outer ring having an inner tooth profile. The number of radially or slidably movable teeth is different from the number of teeth in the annular tooth profile, which causes the rack member to move at a slower speed than the input drive member. Therefore, the rack member constitutes an output drive member. This "radially moving tooth" gearbox design is capable of achieving a high speed reduction ratio between 1:10 and 1:200.

[0007] Gear systems based on radially shifting tooth designs are not typically back-driven, primarily due to reduced efficiency when operating in the reverse drive direction. There are various technical challenges associated with configuring radially shifting tooth design gearboxes for use as speed increasing transmissions, particularly in high torque applications, and the inventions discussed herein are intended to address at least some of these challenges. Summary of the invention

[0008] According to a first aspect of the invention, there is provided a transmission which may have particular use in wind turbine applications, but may also be used in other applications. The transmission comprises a fixed ring gear, a first drive member rotatably supported within the fixed ring gear, the first drive member defining a plurality of radially arranged apertures or holes, each aperture or hole accommodating a tooth element, the tooth element being configured to slide or move within a respective aperture. The tooth element has a tooth tip and a tooth base, and the first drive member further comprises a radially outer surface and a radially inner surface, and wherein the tooth tip of the tooth element engages with a respective tooth surface defined by the fixed ring gear. A second drive member is rotatably supported such that it extends within the first drive member and defines a cam profile which engages directly or indirectly with the tooth base of each of the plurality of tooth elements through an intermediate element such as a pivot pad. The first drive member further comprises a lubrication system / network configured to supply lubricating fluid to at least one of: i) the radially arranged apertures; ii) the radially outer surface of the input member; and iii) the radially inner surface of the first drive member.

[0009] In examples of the invention, the lubrication system comprises one or more fluid lubrication passages, bores or passages extending internally through the material constituting the first drive member. Beneficially, the invention relates to targeting lubrication at targeted points on and in the first drive member by defining the lubrication passages internally within the first drive member. Constructing the first drive member in this manner provides a convenient and mechanically elegant way to deliver lubricating oil directly to the components that need it most.

[0010] In one example, the transmission may form part of a step-up gearbox, wherein rotation of the first drive member causes radial movement of the toothed element by engaging with a fixed ring gear.

[0011] In another aspect, examples of the invention provide a wind turbine comprising a tower on which is mounted a nacelle, the nacelle supporting a rotatable hub, wherein the rotatable hub is coupled to a transmission as defined above.

[0012] Preferred and / or optional features of the invention are set out in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0014] Figure 1 is a perspective view of a horizontal axis wind turbine that may incorporate the present invention;

[0015] Figure 2 is used for Figure 1 A perspective view of a power transmission system of a wind turbine in FIG. 1 , which includes a main shaft, a gearbox or transmission, and a generator;

[0016] Figure 3 yes Figure 2 an exploded perspective view of the transmission of the illustrated system;

[0017] Figure 4 is a view transversely through the transmission showing the arrangement of the main components;

[0018] Figure 5a to Figure 5c is a series of views showing gear tooth elements and associated pivot / tilt pads of a transmission;

[0019] Figures 6a to 6c is a series of views showing the progression of one of the gear tooth elements of the transmission during a load cycle;

[0020] Figure 7 and Figure 8 is a cross-sectional view of the various parts of the transmission, which shows the configuration of the lubrication system;

[0021] Fig. 9 is a schematic diagram of a gear tooth element of a transmission, which illustrates the role of the gear tooth element in the lubrication system;

[0022] Fig.10 is an end view of the transmission, and also illustrates another aspect of the transmission;

[0023] Fig.11 and Fig.12 is a view for a further application of the transmission according to the invention,

[0024] Fig.13 and Fig.14a , Fig.14b An alternative arrangement of gear tooth elements for use with a transmission according to the present invention is shown. DETAILED DESCRIPTION

[0025] Specific embodiments of the present invention will now be described, wherein many features will be discussed in detail in order to provide a thorough understanding of the inventive concept defined in the claims. However, it will be apparent to those skilled in the art that the present invention can be implemented without the specific details, and in some cases, well-known methods, techniques, and structures are not described in detail to avoid unnecessarily obscuring the present invention.

[0026] In order to place the embodiments of the present invention into proper context, reference will first be made to Figure 1 , which shows a typical horizontal axis wind turbine (HAWT) in which a generator rotor assembly according to an embodiment of the present invention may be implemented. Although this particular image depicts an onshore wind turbine, it will be understood that equivalent features will also be found on offshore wind turbines. In addition, although the wind turbine is referred to as a "horizontal axis", those skilled in the art will understand that for practical purposes, the axis is usually slightly tilted to prevent contact between the rotor blades and the wind turbine tower in the event of strong winds.

[0027] Wind turbine 10 includes a tower 12, a nacelle 14 rotatably coupled to a top of tower 12 by a yaw system (not shown), a rotor hub 16 mounted to nacelle 14, and a plurality of wind turbine rotor blades 18 coupled to rotor hub 16. Nacelle 14 and rotor blades 18 are rotated and directed into the wind direction by the yaw system.

[0028] The nacelle 14 houses many functional components of the wind turbine, including the main rotor shaft, generator, gearbox and power converter for converting the mechanical energy of the wind into electrical energy to provide to the grid. Together these components are often referred to as the power train of the wind turbine, while the gearbox and generator are often referred to as the drive train. Figure 2An example of a layout of a portion of a powertrain 19 within the nacelle 14 is shown, including a main shaft 20 extending through a main bearing housing 22, a gearbox 24, and a generator 26. The main shaft 20 is connected to and driven by the rotor hub 16 and provides input drive to the gearbox 24.

[0029] The gearbox 24 increases the speed of the low-speed main shaft through an internal gear (not shown) and drives a gearbox output shaft (also not shown). The gearbox output shaft in turn drives a generator 26, which converts the rotation of the gearbox output shaft into electricity. The electricity generated by the generator 26 can then be converted by other components (not shown) as needed before being supplied to appropriate consumers (such as a grid distribution system).

[0030] All aspects of the gearbox Figure 3 and Figure 4 is shown in more detail in . Figure 3 The general arrangement of the various components of the gearbox 24 is shown in exploded view. Figure 4 The relative positioning of the internal components of the gearbox is shown. Hereinafter, the gearbox components will generally be referred to as the transmission 28 .

[0031] The transmission 28 includes three main components: an input drive member 30 or "tooth carrier", an output drive member 32, and an outer ring gear 34. The transmission 28 is configured to increase the rotational speed between the input drive member 30 and the output drive member 32. In this case, the input drive member 30 will be coupled to the main rotor shaft 20 of the wind turbine, and the output drive member 32 will be coupled to the rotor of the generator 26. The main components of the transmission as described above can be made of suitable materials, such as suitable grades of cast or forged steel. In lower load applications, the components can be made of other materials such as suitable engineering plastics. The selection of the exact material for a particular application will be within the ability of the skilled person.

[0032] At this point, it should be noted that the general arrangement of the transmission is similar to the so-called "Galaxie" (RTM) drive system manufactured by the Wittenstein Group. This type of system is sometimes referred to in the art as a "radially movable tooth" or "slidable tooth" design, and the basis of the present technology is described in US8656809 B2 and US8256327 B2, etc. However, such drive systems tend to be used in speed reduction applications with lighter loads and relatively short working lives, while in the current context, the transmission is intended to be used as a speed increaser to convert the relatively high torque and low speed input drive (approximately 5-15rpm) from the main rotor of the wind turbine to a low torque but high speed output drive (approximately 100-1000rpm) for the gearbox. In addition, in wind turbine applications, the gearbox tends to run for longer periods of time than other applications, for example, a typical wind turbine has a working life of 25 years.

[0033] Back to Figure 3 and Figure 4 The outer gear ring 34 is a rotationally fixed component, which is connected to the main housing 38 of the gear box 24 (see Figure 2 ) is associated with or forms a part of it. Thus, the outer ring gear 34 is in a rotationally fixed relationship with the nacelle of the wind turbine.

[0034] The outer ring gear 34 is configured to define an inner gear profile 40 about its radial inner surface 42. The gear profile 40 extends circumferentially about the axis of rotation of the transmission. The gear profile 40 is defined by a plurality of gear tooth segments 44 or more simply "gear segments".

[0035] It should be noted that the outer profile of each gear segment 44 is shaped to define a portion of a logarithmic profile, which is beneficial in terms of force transmission with the toothed members of the transmission, as will now be discussed. However, the precise tooth geometry is not the focus of the present invention, so for the sake of clarity, further discussion will be omitted.

[0036] The input member 30 is configured to rotate within a space defined by the outer ring gear 34. Similarly, the output member 32 is rotationally supported such that it extends within or through the input member 30 such that it can rotate therein.

[0037] The input member 30 is associated with and physically connected to the main shaft of the wind turbine and therefore rotates at the same speed. It should be understood that in the drawings, the input member 30 is not shown as being connected to the main shaft. However, the input member 30 includes a set of bolt holes on its axial surface, which are used to define a connection interface for the main shaft, or an intermediate coupling member for coupling the input member 30 to the main shaft. It should be noted that the input member 30 can also be connected to the main shaft by a press-fit connection such as a shrink disk.

[0038] The input member 30 is annular in form and defines a radially outwardly facing surface 29, a radially inwardly facing surface 31, and a first axially facing surface 35 and a second axially facing surface 37. The input member 30 is configured to define a circumferentially spaced arrangement of apertures, holes or bores 50, each of which accommodates a respective gear tooth element 52. Thus, the bores 50 act as guides for the respective tooth elements 52 and may therefore be considered guide holes. The radial depth / dimension of the bores 50 is less than the axial length of the gear tooth elements such that the tips of the gear tooth elements protrude from the top surface of the input member 30. It should be noted that in Figure 4 Only two of the gear tooth elements 52 and corresponding holes 50 are labeled in order not to obscure the details of the figure. The exact number of gear tooth elements 52 and corresponding holes 50 is not the subject of the present invention and will not be described in detail here. However, the number may vary between about 20 and 200. In addition, the number of gear tooth elements and gear segments may be selected to vary the gear ratio between the input member 30 and the output member 32, and also to select the relative rotation direction between the input member 30 and the output member 32.

[0039] As is generally known in the art, the input member 30 and the output member 32 may rotate in the same direction, albeit at different rotational speeds, or they may rotate in opposite directions, and the direction of rotation is determined by the relative number of gear tooth elements 52 in the input member 30 and the number of gear segments 44 in the outer gear ring 34. Reference is made to US10830328, which discusses more details regarding the interrelationship between the number of gear segments 44 and the number of slidable tooth elements 52.

[0040] The input member 30 may be configured with a single row of bores 50 and gear tooth elements 52. However, in the example shown, the input member 30 has two rows 53 of bores 50 and gear tooth elements 52 appropriately spaced apart in the axial direction of the transmission. Additional rows are possible, although not currently contemplated. In this context, the above discussion regarding the number of teeth in a row will apply to each row. Note that the axis of rotation of the transmission is in the Figure 3 and Figure 4 This axis is preferably aligned with Figure 2 The axis Y in coincides.

[0041] like Figure 3As shown, each row of holes 50 is circumferentially spaced around the input member 30 in an equiangularly spaced relationship. In the embodiment shown, the angular spacing between the holes 50 in each row is the same for each row and may be between 2 degrees and 20 degrees, for example, depending on the number of tooth elements. However, in theory, there may be a different number of holes 50, and therefore tooth elements 52, in each row. In the example shown, where there are an equal number of holes 50 and tooth elements 52 in each row, the holes 50 in one row are angularly offset from the holes 50 in the other row. This can be understood by observing a line L1 taken through the center of one hole 50 in one row and a line L2 taken through the center of the nearest hole 50 in the other row. It can be seen that there is a small angular offset between the holes 50 in the two rows. The angular offset may be as high as 50% of the angular spacing between adjacent holes 50. For example, in a particular row, the angular offset may be 5% or 10% or 20% or 30% or 40% of the angular spacing between two adjacent holes 50. For example, for a row with 30 holes, the angular spacing would be 12 degrees. Thus, the angular offset between holes in adjacent rows can be up to 6 degrees.

[0042] The rotational action of the input member 30 causes the corresponding gear tooth elements 52 to be driven radially inward by the gear profile 40 as they slide within the bore 50. Since the number of gear tooth elements 52 does not match the number of gear segments 44 of the gear profile 40, the result is that each gear tooth element 52 is at a different radial lift height within its corresponding bore 50. This imparts an undulating motion pattern to the gear tooth elements 52, which in turn impart a rotational drive force to the output member 32, as will now be described.

[0043] Reference will be made in more detail to the gear tooth element 52, and also to Figure 5a to Figure 5c It will be seen that each gear tooth element 52 includes a tooth tip region 56 and a tooth base region 58, both of which are aligned on the tooth axis B. The tooth tip region 56 is positioned radially outwardly relative to the tooth base region 58. Figure 3 and Figure 4 It is not clearly seen in the figure, but it should be understood that the shape of the tooth tip region 56 is configured to complement the shape of the corresponding gear segment 44 of the outer ring gear 34. In the example shown, each side 60 of the tooth tip region 56 can be shaped to define a substantially flat surface, but in other examples, the side can define a portion of a logarithmic spiral or have a certain degree of curvature.

[0044] While the tooth tip regions 56 of the gear tooth elements 52 engage the gear profile 40 of the outer ring member 34 , the tooth base regions 58 of the gear tooth elements 52 engage the output member 32 .

[0045] Especially Figure 4As shown, the output member 32 has a non-circular circumferential outer surface 61. More specifically, in the example shown, the shape is elliptical. Therefore, in this example, the output member 32 is in the form of a cam so as to provide a shaft cam drive with two cam peaks. Other examples may provide a single cam peak or more than two cam peaks. The shape of the output drive member 32 allows the gear tooth element 52 to drive it with a rotational motion.

[0046] In order to reduce friction between the gear tooth element 52 and the output drive member 32 , a bearing arrangement 62 is provided.

[0047] The bearing assembly 62 includes a plurality of pivot pads 64, only some of which are located Figure 4 . Each pivot pad 64 is associated with a respective one of the gear tooth elements 52 and serves as a fulcrum against which the respective base region 58 of the gear tooth element 52 bears. The gear tooth element 52 thus engages the cam surface of the output member 52 to transmit force thereto, thereby acting on and driving the output member. However, in this example, the tooth element 52 acts indirectly on the cam surface by abutting against the pivot pad 64, but in this context, the terms "engage", "act on" and "driven by" are considered to cover direct engagement as well as indirect engagement via a pivot pad or other functionally equivalent bearing type element.

[0048] The action of the pivot pad 64 is Figure 5a to Figure 5c Schematically illustrated in FIG. 1 . It can be seen that the pivot pad 64 includes a pad portion 66 and a pivot or fulcrum portion 68. The pivot portion 68 projects upwardly from the pad portion 66 and is shaped to complement a recess 70 defined in the underside of the base region 58 of the gear tooth element 52. The pivot portion 68 may define a partially spherical or partially cylindrical protrusion. The precise geometry is not critical to the present invention, but it should allow the pivot pad 64 to smoothly pivot relative to the gear tooth element 52, as can be seen in the accompanying drawings, wherein Figure 5a The pivot pad 64 is shown in a neutral position, and Figure 5b and Figure 5c The pivot pads 64 are shown tilted to the left and right, respectively.

[0049] The pivot pads 64 are arranged to extend around the circumferential outer surface of the output member 32. Each pivot pad 64 is associated with a corresponding gear tooth element 52. Since the pivot pads 64 slide on the outer surface of the output member 32, it is preferred to provide suitable means to assist lubrication between these components. This can be achieved by a low friction coating on the underside of the pivot pads 64 and / or a low friction coating on the outer surface of the output member 32. Alternatively, the pivot pads 64 can be mounted on a suitable plain bearing or roller bearing system 63 (such as Figure 41 and 2. The pivot pads 64 may be appropriately coupled to one another. To limit the pivot pads from moving in the axial direction on the output drive member 32, the pivot pads 64 may be received in shallow guide channels (not shown) defined in the outer surface of the output member 32, or other functionally similar arrangements.

[0050] The benefit of the pivot pads is that they more effectively transfer the linear drive force vectors generated by the various tooth elements into the camming surface of the output member 32 as it undulates beneath the pivot pads 64 .

[0051] As a further illustration, Figures 6a to 6c is a series of diagrams showing the short rotational phases of the input member 30 and the output member 32. In these diagrams, only a single one of the gear tooth elements 52 is shown for clarity. However, by observing Figures 6a to 6c , the relative movement of the input member 30 and the gear tooth element 52 is apparent, as is the effect of forces applied to the gear tooth element 52 on the output member 32 .

[0052] First reference Figure 6a , which can be considered as a reference position at the beginning of the tooth loading cycle, wherein the tip region 56 of the gear tooth element 52 is located in the groove 44a of the gear tooth segment 44. It should be noted that the outer ring gear 34 is stationary, while the input member 30 and the output member 32 rotate relative to it, but at different rotational speeds. The rotation direction of the input drive member 30 is Figure 6a , and can be considered clockwise in this example. Similarly, the rotational direction of the output member 32 is labeled R2, and is also clockwise in this example. As described above, in some examples, the input member 30 and the output member 32 can be configured to rotate in opposite directions.

[0053] At this point, it will be noted that although a single gear tooth element 52 is shown, the input drive member 30 is shown in partial form for the sake of clarity. The movement of the input drive member 30 can be achieved by adjusting the position of the gear tooth element 52 to the position of the gear tooth element 52. Figures 6a to 6c The movement of the gear tooth element 52 relative to the outer gear ring 34 can be understood by comparing it with the gear segment 44 that is engaged therewith. Figure 6a In the embodiment, the output member 32 is in a rotational position where the height of the cam shape is at a maximum. Therefore, the cam shape provided by the output member 32 can be regarded as being in a rotational position where the height of the cam shape is at a maximum. Figure 6a The top dead center position in.

[0054] When the input member 30 is driven in the clockwise direction, a force will be exerted by the raised side 80 of the gear tooth segment 44 on the tooth tip area 56 of the gear tooth element 52. This force Figure 6aThe component of force F1 will be in the vertical downward direction (in the orientation of the drawing) and is shown here as F2. Therefore, when the output member 32 rotates, and when the gear tooth element 52 passes through the Figure 6a In the top position shown, the gear tooth element 52 will begin to exert a force on the camming surface of the output drive member 32 via the pivot pad 64 .

[0055] Compare Figure 6b and Figure 6a ,exist Figure 6b It will be seen that the output member 32 has rotated in a clockwise direction through an angle θ of approximately 30 degrees. In contrast, the gear tooth element 52 has only moved a small fraction of a degree relative to the outer ring member 34 , which illustrates the speed increasing configuration of the transmission 28 .

[0056] It can be seen that the cam shape of the output member 32 is Figure 6b The gear tooth element 52 has changed position in the pivot pad 64 so that the vertical force F2 applied by the gear tooth element 52 via the pivot pad 64 now acts on the cam-shaped descending ramp 82. Therefore, the gear tooth element 52 contributes a rotational force to the output drive member 32, which combines with the forces generated by the other gear tooth elements to drive the output member 32 to rotate.

[0057] Figure 6c Basically Figure 6a and Figure 6b Same, but showing the gear tooth element 52 further along its loading cycle. Once the gear tooth element 52 has gone through the loading cycle, as shown, it is driven outwardly by the cam surface of the output member 32 and is not loaded during this movement.

[0058] Having described the general arrangement of the transmission 28 , the discussion will now focus on various aspects related to lubrication of the moving components of the transmission 28 .

[0059] The transmission of the present invention is suitable for high load applications, such as the main gearbox for a wind turbine. Although lubrication of such a sliding tooth design gearbox is not so important for small-scale and low-load applications, for high torque applications generated by the main shaft of a wind turbine, adequate lubrication is essential for reliable operation of the transmission.

[0060] With this in mind, Figures 7 to 10 Various features of the transmission 28 are illustrated in relation to the lubrication system.

[0061] First refer to Figure 7 and Figure 8 It should be noted that these figures show different cross-sections of the transmission 28 cut along the axis of rotation at different angular planes, so that different details of the transmission 28 can be more fully understood. For the sake of clarity, the outer ring gear 34 has been omitted.

[0062] The transmission 28 includes a lubrication system 100. The lubrication system 100 includes a network 102 of fluid passages, channels or pathways configured to provide lubricating oil to various contact surfaces of the transmission, such as between the radially outer surface of the output member 32 and the pivot pads 64 and between the radially outer surface of the input member 30 and the outer ring gear 34 (not shown), and to the gear apertures 50.

[0063] The lubrication network 102 includes fluid passages disposed in the input member 30. Figure 7 As can be seen in FIG. 1 , the lubrication network 102 includes one or more fluid inlets 104 defined in a hub portion 106 of the input member 30 . Figure 7 Two fluid inlets are shown, but more fluid inputs may be provided in the hub portion 106. At present, it is contemplated that four fluid inlets will be provided, preferably in an equiangularly spaced relationship.

[0064] The fluid inlet 104 is supplied with lubricating fluid from a suitable fluid supply system 107. This may include a reservoir or tank 108 and a fluid pump 110, and these are Figure 7 108 and the pump 110. The rotatable coupling 112 may be configured to convert the fluid supply from the fixed reference frame of the reservoir 108 and the pump 110 to the rotating reference frame of the input member 30. The details of the rotatable coupling 112 are not the primary focus of the present invention and therefore will not be described herein for the sake of clarity. In addition, it is deemed to be within the scope of those skilled in the art to configure a suitable rotatable coupling known in the art.

[0065] Reference Figure 7 106. Referring to the fluid inlets 104 visible in FIG. 106, it will be appreciated that the fluid inlets 104 are respectively connected to intermediate passages 114 that radiate generally radially outward into an outer portion 116 of the input member 30. The outer portion 116 is positioned radially outward of the hub portion 106. Here, the fluid inlets 104 are shown extending in an axial direction through the input member 30, and more specifically through the hub portion 106. The axially extending fluid inlets 104 provide a convenient way to connect the rotatable coupling 112 to the radially extending passages within the input member 30.

[0066] Each of the intermediate passages 114 has a proximal end 114a located at the axially extending inlet passage 104 and a distal end 114b connected to a first fluid distribution lane or manifold 120. It should be noted that the fluid distribution lane 120 extends circumferentially around the inlet member 30, and particularly in the outer portion 116 thereof. In this example, the fluid distribution lane 120 is at least partially defined by a circumferential groove or channel 122 in the axial face of the input member, and is closed by a closing plate 124. The circumferential channel 122 extends circumferentially around at least a portion of the input member 30. This configuration provides a convenient means of forming the fluid distribution lane 120 in the input member 30.

[0067] The fluid distribution gallery 120 provides a volume from which lubrication fluid can be supplied to a variety of locations in the transmission. Some of these locations will now be described.

[0068] like Figure 7 As can be seen in the drawing, the first supply passage 125 extends generally in a radial direction from the fluid distribution lane 120 to the radial outer surface 29 of the input member 30. This can be used for the purpose of providing lubricating oil to the contact point between the outer ring gear 34 and the tip of the gear tooth element 52. Additionally, the passage 125 can be drilled out of the passage 114. If the passage 125 is not needed, it can be blocked with a suitable sealing plug (not shown).

[0069] The second supply passage 126 may extend from the fluid distribution lane 120 or from another passage (as shown here) to the radially inward surface 31 of the input member 30. In this example, the second supply passage 126 extends in a radial direction. Figure 7 1 and 2 to illustrate a possible path of the passage 126 through the input member 30 , but it should be noted that other paths are possible. The second supply passage 126 allows lubricating oil to be supplied to the outer circumferential surface of the output member 32 .

[0070] In addition to the first supply channel 125 and the second supply channel 126, the lubrication network 102 also includes a channel that supplies lubricating fluid directly to the gear tooth element 52. More specifically, the channel supplies lubricating fluid to the gear tooth aperture 50 in which the gear tooth element 52 reciprocates. In this regard, the third supply channel 130 extends in a generally axial direction from the first fluid distribution lane 120 to the second fluid distribution lane 132. The second fluid distribution lane 132 is located on a side of the input member 30 opposite to the first fluid distribution lane 120.

[0071] In this example of the invention, the second fluid distribution roadway 132 is also defined on the axially facing surface 134 of the input member 30, and more specifically, on the outer portion 116 of the input member 30. Here, the second fluid distribution roadway 132 extends circumferentially around the input member, and thus is circular in shape when viewed from the axial direction. In this example, the second fluid distribution roadway 132 is defined by an annular roadway plate 140 attached to the axial surface 134 of the input member 30. The roadway plate 140 defines an annular channel 142. The annular channel 142, together with the adjacent axial surface 134 of the input member 30, defines the volume of the second fluid distribution roadway 132.

[0072] The gear tooth apertures 50 are supplied with lubricating fluid from the second fluid distribution channel 132 via the corresponding fourth supply passage 144. Figure 8 14, the fourth supply passage 144 extends from the second fluid distribution lane 132. The fourth supply passage 144 has a first end 144a in communication with the second fluid distribution lane 132 and a second end 144b in communication with the gear tooth aperture 50. With this configuration, lubrication fluid can be supplied from the fluid inlet 104 via the intermediate passage 114 to the first fluid lane 120, and from there to the second fluid distribution lane 132 via the third supply passage 130. Fluid can be supplied from the second fluid distribution lane 132 to the gear tooth aperture 50 via the fourth supply passage 144.

[0073] It should be noted that there may be a fourth supply passage 144 for each of the corresponding gear tooth apertures 50. It should also be noted that Figure 8 As can be seen in FIG. 1 , the fourth supply channel 144 is arranged to supply two rows of gear tooth apertures 50 .

[0074] exist Figure 7 In another example of a lubrication system shown in FIG. 1 , the lubrication system is slightly simpler and includes similar components, the repetition of which is omitted here for the sake of brevity. The third supply channel 130 is used directly to supply the gear tooth apertures 50. These axial channels 130 are closed by another closing plate placed on the axial surface 134 of the input member 30. Therefore, there is no need to mainly Figure 8 Additional elements 132, 142, 144, 144a and 144b are shown in FIG.

[0075] Compared with this variant, Figure 7 and Figure 8 The lubrication system has the advantage of being more accessible and easier to manufacture in the installed state, and flow control devices can be replaced more easily to analyze any effects on oil distribution.

[0076] Alternatively, the gear tooth elements 52 may be specifically configured to most efficiently utilize the lubricating fluid delivered to the gear tooth apertures 50 . Figure 8 The internal configuration / structure of a representative gear tooth element in the gear tooth element 52 can be seen in FIG. Fig. 9 Described in more detail in .

[0077] It will be noted that the gear tooth element 52 shown in the illustrated example includes external channels and passages as well as internal channels and passages to transport lubricating fluid through the gear tooth element 54 and between different portions of the gear tooth element 56. More specifically, the illustrated gear tooth element 52 includes a first lubrication port 150 located at a first axial position and a second lubrication port 152 located at a second axial position. The internal lubrication passage 154 provides fluid communication between the first lubrication port 150 and the second lubrication port 152. In this manner, lubricating fluid can be transported between the first lubrication port 150 and the second lubrication port 152, to which the fluid is transported by the supply passage 144 present in the wall of the gear tooth aperture 50. The second lubrication port 152 is located lower on the gear tooth element 52 than the first lubrication port 150, which is closer to the tooth tip region 56.

[0078] In principle, the internal lubrication channel 154 can be of any shape, but in the illustrated example, it is shown as being formed by an axial channel portion 156 and a first radial channel portion 158 and a second radial channel portion 160. The radial channel portions 158, 160 link the axial channel portion 156 to the first port 150 and the second port 152, respectively. Note that Fig. 9 The terms "radial" and "axial" are used in the context of the gear tooth element 52 in the Fig. 9 is set in the context of the tooth axis B.

[0079] To improve the distribution of lubricating fluid around the outer surface of the gear tooth element 52, one or both of the first lubrication port 150 and the second lubrication port 152 may be associated with a corresponding circumferential groove extending around a portion of the gear tooth element 52. Preferably, the groove extends around the entire circumference of the gear tooth element. Fig. 9 , the first circumferential groove 162 is positioned at the first lubrication port 150. The second circumferential groove 164 is positioned at the second lubrication port 152. Thus, as the gear tooth element 52 slides up and down in the gear tooth aperture 50, the lubricating fluid in the grooves serves to coat the outer surface of the gear tooth element 52. The grooves 162, 164 also serve as lubricating oil reservoirs.

[0080] By inspection Fig. 9It can be noted that the first lubrication groove 162 has a greater width when considered along the axis B of the gear tooth element 52 than the axial width of the second lubrication groove 164. Without wishing to be bound by theory, it is currently believed that the lower portion of the gear tooth element 52 is subjected to lower loads, so the narrow width of the second lubrication groove 164 may be sufficient. In other examples of the present invention, the widths of the two lubrication grooves can be the same or nearly the same. The width of the upper groove 162 can be adjusted to control how much oil is allowed to enter the passage of the gear tooth element 52. A wider upper groove 162 will mean that the upper groove 162 overlaps the supply passage 144 longer during the up and down sliding of the teeth.

[0081] In the illustrated example, it will be noted that the internal lubrication passage 154 extends to the base of the gear tooth element 52. Thus, in this manner, lubrication fluid can be provided to the pivot pads ( Fig. 9 156 and the gear tooth element 52. In an alternative example, a closure element 165 may be secured to the bottom of the gear tooth element 52 to close the internal passage 156. However, it should be noted that this is optional and in some examples of the present invention, the passage 156 may remain open at the base of the tooth element 52.

[0082] The axial position of the second lubrication groove 164 is selected so that it remains within the gear aperture 50 when the gear tooth element 52 is in its lowest position, as shown in FIG. Fig. 9 This ensures that the lubricating oil supplied by the groove is applied to the orifice / hole 50 most effectively.

[0083] Similarly, the axial position of the first lubrication groove 162 is selected so that it is retained within the gear tooth aperture 50 through the reciprocating movement of the gear tooth element 52 .

[0084] Preferably, all of the gear tooth elements 52 have lubrication passages as described above, although the present invention extends to only a subset of the gear tooth elements provided with such passages.

[0085] As will be appreciated from the above discussion, the internal passages of the input member 30 and gear tooth element 52 allow lubrication fluid to reach important components of the input member 30 , which is particularly important for high load applications where lubrication is more critical to improving transmission wear resistance.

[0086] In some examples of the present invention, the lubrication system 100 can be configured so that the lubrication fluid is supplied to the gear tooth apertures 50 by a constant flow. The flow may be variable in volume, but constant in the sense that there is always some flow to the gear tooth apertures 50. However, in another example, the lubrication system 100 can be configured so that the flow of lubrication fluid to the gear tooth apertures 50 is intermittent. In this way, the lubrication system can be configured so that the lubrication fluid is delivered to a selected group of gear tooth elements 52 only during a predetermined loading phase for these corresponding tooth elements. Conversely, when the gear tooth element is not in a load phase, the delivery of lubrication fluid to the gear tooth element can be stopped or interrupted or minimized. This is a benefit because it means that a lower volume of lubricating fluid is circulating in the system at any time. This makes the system more efficient, or can reduce the demand on the supply pump, thereby enabling miniaturization. In addition, this measure can avoid overloading the various components of the structure with the lubricating fluid.

[0087] In one example, to achieve this function, the flow of lubricating fluid can be controlled by an electronically operated flow control valve device, which is not illustrated in the figure. In this arrangement, each of the fourth supply channels 144 or a group of such channels can be connected to an electronically operated flow control valve. Such a control valve can be configured to open the fluid flow through the corresponding fourth supply channel or channel group to ensure that the lubricating fluid is supplied to the loaded teeth and release the fluid flow to the unloaded teeth.

[0088] In other examples, this advantage can be achieved without an electronically controlled flow control valve, which would otherwise add complexity to the system. Figure 7 , Figure 8 and Fig.10 Describing one such solution, the figure shows the use of a flow control device 170, which may also be considered as a valve device.

[0089] Here, the flow control device 170 takes the form of a disc or plate. The flow control device 170 is circular in shape and has a central aperture 172 that is received above the output member 32 and attached to its radial shoulder 174. The manner in which the flow control device 170 is coupled to the output member 32 is not shown in the figure, but this can be achieved by an appropriate arrangement of mechanical fasteners such as bolts.

[0090] The location of the attachment point of the flow control device 170 to the output member 32 is such that a planar surface of the flow control device 70 abuts the axial facing surface 134 of the input member 30. In this manner, a radially outer edge region 176 of the flow control device 170 overlaps the fourth supply passage 144.

[0091] like Figure 7 and Figure 8 As can be seen particularly well in the inset in FIG. 1 , the radially outer edge region 176 of the flow control device 170 extends below the roadway plate 140. Suitable sealing means (not shown) may be provided at the contact surface between the roadway plate 140 and the flow control device 170.

[0092] The flow control device 170 is provided with an orifice 180 that selectively exposes certain of the fourth fluid passages 144 leading to the gear tooth apertures 50. Fig.10 The orifice 180 in the form of an arcuate slot can be clearly seen in the figure. Here, four arcuate slots are provided, each of which exposes approximately five fluid channels 144 that can be seen through the slots, only some of which are labeled for clarity. Here, it should be understood that Fig.10 The roadway plate 140 is not shown in order not to obscure the details of the aperture 180 .

[0093] The purpose of the flow control orifices 180 is to enable fluid to flow from the second fluid distribution lanes 132 through the orifices 180 into the corresponding fourth fluid passages 144 leading to the gear tooth orifices 50. In this manner, when the fluid control device 170 rotates synchronously with the output member 32, the slots 180 allow lubrication fluid to flow to only selected ones of the gear tooth elements 52, i.e., those that are experiencing a load phase. Thus, during rotation of the flow control device 170, the flow control orifices 180 can be viewed as gradually uncovering one set of passages while covering another set of passages.

[0094] Many modifications may be made to the specific examples described above without departing from the scope of the invention as defined in the accompanying claims. Features of one embodiment may also be used in other embodiments, in addition to or as an alternative to such an embodiment.

[0095] In the above discussion, a speed increasing gearbox has been described as being used in a wind turbine power train as a device for increasing the rotational speed of the main shaft to a speed suitable for the input shaft of the generator.

[0096] Those skilled in the art will appreciate that this is not the only application for such a transmission. As an example, Fig.11 and Fig.12 Two further applications are shown in which the transmission may be used. In the following discussion, it may be assumed that the internal details and functionality of the transmission are the same as described above.

[0097] First refer to Fig.11, the transmission of the present invention may be used in agricultural gearbox applications. Here, for example, an agricultural machine such as a tractor 200 provides a power take-off coupling 202, which is a rotating shaft driven by the engine of the tractor 200, as is known in the art. The power take-off coupling 202 may typically be driven between 200 and 600 rpm, and depends on the engine speed. For some agricultural applications, this rotational speed may be sufficient. However, for other applications, a higher rotational speed may be required. Therefore, in Fig.11 In the embodiment of the present invention, a transmission 228 is provided which receives a power take-off coupling 202 from a tractor 200 as a drive input. Here, the transmission 228 is shown attached to the tractor 200, but this is not necessary, particularly if mobility is not required. The transmission 228 converts the relatively high torque and low speed drive input from the power take-off coupling 202 into a higher speed but lower torque drive input 230 that is input to a hydraulic pump 232. As an example, the rated operating speed of the pump may be between 1200 and 2000 rpm. The hydraulic pump 232 may be a gear pump or any other suitable form of pump. In the application shown, the pump 232 is used to draw water from a nearby stream 234 through an input pipe 236 and pump the water to a water storage container 240 through an outlet pipe 238.

[0098] Advantageously, the technical advantages of the transmission of the present invention, such as low backlash and smooth operation, minimize further vibrations on the power take-off coupling 202 and reduce operating noise for the machine operator.

[0099] Fig.12 Another application is shown in FIG. 3 , in which a transmission 328 according to the present invention is integrated into a fluid power generation system 330 .

[0100] The power generation system 330 includes a so-called Archimedean screw device 332 arranged at an oblique angle relative to a flowing body of water such as a river or stream 334. An inlet 336 of the screw device 332 is provided at an upper end, while a discharge or outlet 338 is provided at a lower end thereof. The general form of the screw device is conventional.

[0101] A suitable structure 340 is provided to form a supply passage 342 through which a water stream 344 is supplied to the inlet 336 of the screw device 332, which causes its rotation, as is well known. The structure 340 may be, for example, an earth or concrete reservoir, but other structures are possible.

[0102] The screw device 332 includes a drive shaft 346, which supports the screw device 332 on suitable bearings (not shown) and provides an output drive. According to the present invention, the drive shaft 346 is connected to a gearbox or transmission 328. Since the screw device 332 has only a low rotation rate, such as 0.2 to 1 Hz, the transmission 328 provides a speed increase function. Therefore, the transmission 328 includes an output drive shaft 348 coupled to a generator 350.

[0103] It will be appreciated that the compact arrangement of the transmission according to the invention and other advantageous characteristics such as low noise and low clearance make it advantageous for such applications where installation space is at a premium. In addition, low clearance and smooth operation reduce wear on other components included in the drivetrain.

[0104] In the examples of the invention described above and shown in the accompanying drawings, the transmission has been described as a speed increasing transmission in which the input member 30 receives rotational drive from the main shaft of the wind turbine at a relatively low speed and the output member 32 provides a higher rotational output speed to the generator 26. Although this is the application currently contemplated for the transmission, as Fig.11 and Fig.12 , which is technically advantageous for applications other than wind turbines, but here, it should be noted that the transmission of the present invention can also be "reverse drive", which means that it can be used as a speed reducer transmission. Therefore, in this case, the radially inner output member 32 as described above can receive rotational drive from a prime mover (e.g., an internal combustion engine or an electric motor) with a relatively high speed and relatively low torque, while the radially outer input member 30 will provide forward drive to a load (e.g., a vehicle driveline or a lifting system) with a lower output speed but higher torque as described above. Therefore, in this case, the input member 30 of the transmission can be more generally regarded as a first drive member, while the output member 32 can be more generally regarded as a second drive member. In either operating mode, that is, when operating as an acceleration transmission or a speed reduction transmission, the rotational drive movement of the input member 30 will result in radial movement of the tooth element 52. Conversely, when the output member 32 is driven, it is the rotation of the output member 32 that causes the radial movement of the tooth element 52, which in turn means that the input member 30 also rotates. However, in this operating mode, the transmission can also be back-driven, meaning that rotational movement of the input member 30 results in radial movement of the tooth element 52. Thus, rotational movement of the input member 30 can be considered to be associated or linked to radial movement of the tooth element 52.

[0105] The invention is most preferred primarily in unidirectional applications (which are typically high torque applications, such as the above-mentioned wind turbine applications). However, the invention can also be applied in other fields where high power density, high torque density, large hollow shaft ratio, favorable damping behavior, high stiffness, zero or reduced clearance or backlash, high synchronicity, or generally a compact design are required. Even for bidirectional applications, such as robots, machine tools, industrial drive trains, servo motor torque reduction, packaging machines and milling machines, the invention will be an improvement over the known prior art.

[0106] In the above discussion, the transmission includes a lubrication system that supplies lubricating fluid to specific locations and components within the transmission because this is often an effective way to achieve adequate lubricity while reducing fluid requirements. Because the lubricating fluid is delivered to where it is needed, the lubrication system of the present invention can be considered to be a "dry sump" system, which does not have a fluid collector / sump / bath in which the lubricating fluid can collect and through which the components of the transmission can pass or into which the components can be at least partially immersed to aid lubrication. However, it is contemplated that in some examples of the present invention, the transmission can also be configured to include an oil sump or oil bath. This can be used as a fluid collector for supplying lubricating fluid back to the main fluid tank, and / or it can also be configured so that various components (e.g., input / output components and tooth elements) can be exposed to fluid in the sump during rotation.

[0107] In the examples of the invention described above, various features of the tooth element have been described and illustrated. Generally, the tooth element comprises a cylindrical tooth body that transitions to a tapered tooth tip or head region that terminates at a tip or point. The tooth body in the illustrated examples is cylindrical and matches the tooth aperture / guide so that they can slide relative to it. Although the tooth element and aperture / guide are shown as having a circular cross-section, in principle other cross-sections are also acceptable.

[0108] Another type of tooth element is Fig.13 as well as Fig.14a and Fig.14b In these figures, the same reference numerals will be used to refer to the same and / or equivalent features as the previously shown examples.

[0109] exist Fig.13 , three tooth elements 52 are shown in their respective input members 30. The outer ring gear 34 (like the output member 32) is also partially shown with the pivot pad 64 and the bearing layer 300 located between the outer surface of the output member 32 and the pivot pad 64. It will be understood that the tooth member 52 shown in the center of the image is in a "top dead center" position relative to its respective gear tooth segment 44, while the other tooth elements 52 are in slightly laterally offset positions.

[0110] Also refer to Fig.14a and Fig.14b It will be apparent that the tooth tip region 56 presents a different shape than in the previous examples.

[0111] The tooth element 52 includes a tooth body 302 having a tooth base 304 configured to engage with an adjacent pivot pad 64 ( Fig.14a / Fig.14b not shown) joined.

[0112] The tooth tip region 56 is adjacent to the tooth body 302 distal from the tooth base 304. The tooth tip region 56 is defined by a side section 308 that is separated from the tooth body 302 by a shoulder 310. Fig.14a As shown in FIG. 3 , a left shoulder 310 a and a right shoulder 310 b are provided.

[0113] The shoulder 310 is located intermediate the top of the tooth body 302 and the side section 308 of the tooth tip region 56. The shoulder 310 and the side section 308 together form the tooth tip region 56 of the tooth element 52.

[0114] The tooth body 302 has a generally constant cross-section over the body length L along the longitudinal axis B of the tooth element 52, which cross-section is circular in this example, although this is not the case and other cross-sectional profiles are acceptable. In the case where the cross-section is not circular, the cross-sectional profile can be generally constant along the longitudinal length of the tooth body 302. The tooth body 302 contacts the tooth aperture 50 or "guide" of the input member 30 over the entire length of the tooth body 302, so that force can be transmitted between the tooth element 52 and the corresponding aperture via a contact surface, contact line or contact point.

[0115] The side segments 308 include tooth flanks 320 that may engage corresponding surfaces of the gear tooth segments 44 on the outer ring gear 34 .

[0116] Fig.14b The tooth element 52 is shown as viewed perpendicularly from the tooth flank 320. As will be apparent, the tooth flank 320 is a major planar surface extending from the tooth tip toward the tooth body 302, and in particular the shoulder 312.

[0117] The tooth side 320 includes a straight generally flat section marked as 322 and a first transition section 324 / second transition section 326. The generally flat section 322 may have some curvature, although it is shown as a plane in the figure. The first transition section 324 is positioned toward the tip of the side 320 and extends toward the tip to provide a slightly rounded end instead of a sharp tip shape, thereby reducing stress concentration. The second transition section 326 is located at the other end of the side 320 and merges with the shoulder 310.

[0118] The side surfaces 320 define an angle relative to the tooth axis B. As shown, the angle α of each side surface is approximately 20 degrees, although this is exemplary only and other angles are acceptable. As a result, the taper angle of the tooth tip is approximately 40 degrees. Currently, as a non-limiting example, it is contemplated that taper angles between 30 and 60 degrees are acceptable.

[0119] The presence of the shoulder 310 means that a step is formed between the upper end of the tooth body 302 and the tooth side surface 320. Fig.14a As shown in FIG. 3 , a tooth side line 331 corresponding to an inner tangent line of the tooth side surface 320 intersects the volume of the tooth body 302 .

[0120] The shoulder 310 provides a curved, rounded or concave transition between the top of the tooth body 302 and the inclined side 320. As shown, the axial lower end of the shoulder 312 is horizontal, and from this point, the shoulder 310 bends upward through the lower transition section 326 to merge into the side 320. The curvature of the transition section 326 can be rounded. The shoulder 312 and the transition section 326 can be machined more finely than the tooth side 320.

[0121] The advantage of providing the shoulder 310 relative to the tooth flank 320 may be that splash losses when the tooth element contacts the gear profile can be reduced. In particular, the surface area of ​​the tooth flank can be reduced by the shoulder 310, thereby requiring lubricating oil to be drained from a smaller surface.

[0122] The tooth elements of the present invention may be of any suitable material, but it is currently envisaged that suitable grades of stainless steel are best suited for high load applications. However, in other applications, materials other than steel may be suitable, such as plastics. Similar considerations apply to the materials of the outer ring gear, input member and output member. At least a portion of the tooth element is configured to be flexurally rigid. In this case, the term "flexural rigidity" is generally understood in the art to mean that, due to the rigidity of the tooth material, the bending deformation of the tooth is small, so they are at least substantially unimportant to the kinematics of the gear transmission. In particular, flexurally rigid teeth include teeth made of metal alloys (in particular steel, or titanium alloys, nickel alloys or any other alloys). In addition, flexurally rigid teeth of plastics can also be provided, in particular in transmissions in which the outer ring gear and input / output members are also made of plastics. Metal / alloy components have the advantages of extremely high torsional rigidity and the ability to withstand high loads. Plastic gears have the advantage of being lightweight. In particular, the term "flexural rigidity" refers to the flexural rigidity around the transverse axis of the tooth. In particular, this means that, when the tooth is considered as a rod from the tooth base to the tooth flank area, bending deformations between the tooth flank area and the tooth base are at least substantially excluded, thereby providing bending stiffness. Due to the bending stiffness, a very high resistance to loads and torsional stiffness of the gear arrangement is achieved.

Claims

1. A transmission, comprising: Fixed gear ring (34); a first drive member (30) rotatably supported within the fixed gear ring (34), the first drive member (30) defining a plurality of radially arranged apertures (50), each of the apertures accommodating a tooth element (52), each tooth element (52) having a tooth tip region (56) and a tooth base (58), the first drive member (30) comprising a radial outer surface (29) and a radial inner surface (31), and wherein the tooth tips (58) of the tooth elements (52) engage with a corresponding gear profile (40) defined by the fixed gear ring (34), a second drive member (32) rotatably supported so as to extend within the first drive member (30), the second drive member defining a cam profile (61) engaging with each of the plurality of tooth elements, wherein the first drive member (30) comprises a lubrication system (100, 102) configured to supply lubrication fluid to at least one of: i) the radially arranged orifices (50); ii) the radially outer surface (29) of the first drive member; and iii) the radially inner surface (31) of the first drive member (30).

2. The transmission according to claim 1, wherein: The lubrication system includes at least one passage extending through the first drive member (30).

3. The transmission according to claim 1 or 2, wherein: The first drive member (30) is an input member and the second drive member (32) is an output member, wherein the output member acts on and is driven by the tooth base (58) of each of the plurality of tooth elements (32), thereby causing the output member (32) to rotate.

4. A transmission according to any one of the preceding claims, further comprising a rotating fluid coupling (112) for interfacing between a hydraulic supply (108, 110) in a stationary reference frame and the lubrication network (100, 102) in a rotating reference frame.

5. The transmission according to claim 4, wherein: The rotary fluid coupling (112) is connected to at least one axially extending fluid inlet (104) defined in the first drive member (30).

6. A transmission according to any one of the preceding claims, wherein: The lubrication system (100, 102) includes a fluid distribution channel (120) extending around at least a portion of the first drive member (30).

7. The transmission according to claim 6, wherein: The fluid distribution channel (120) is at least partially defined by a channel (122) defined in an axially facing surface (35) of the first drive member (30).

8. A transmission according to any one of the preceding claims, wherein: The lubrication system (100, 102) includes one or more generally axial passages (130, 144) that open into corresponding ones of the radially arranged apertures (50).

9. A transmission according to claim 8 when dependent on claim 5, wherein: The one or more generally axial passages (130, 144) span between respective radially disposed orifices (50) and the fluid distribution channel (120).

10. A transmission according to any one of the preceding claims, wherein: The lubrication system (100, 102) includes one or more first substantially radial passages (114, 125) opening into the radially outer surface (29) of the first drive member (30).

11. A transmission according to claim 10 when dependent on claim 6, wherein: The first generally radial passage (114, 125) extends from the fluid distribution channel (120).

12. A transmission according to any one of the preceding claims, wherein: The lubrication system (100, 102) comprises one or more substantially radial second passages (126) opening into the radial inner surface (31) of the first drive member (30).

13. A transmission according to claim 12 when dependent on claim 6, wherein: The generally radial second passage (126) extends from the fluid distribution channel (120).

14. The transmission according to claim 13, wherein: The generally radial second passage (126) extends radially inwardly to a hub portion (106) of the first drive member (30).

15. A wind turbine (10) comprising a tower (12) on which a nacelle (14) is mounted, the nacelle supporting a rotatable hub (16), wherein: The rotatable hub is coupled to a transmission according to any one of the preceding claims.

Images