Variable pitch bearing and wind turbine including same

Abstract

The utility model provides a kind of variable pitch bearing and wind turbine including it, variable pitch bearing includes inner ring, outer ring and several conical rollers, the side of outer ring towards inside is recessed and forms first recessed cavity, the side of inner ring towards outside is protruding and forms boss, boss extends into first recessed cavity to separate first recessed cavity into first raceway and second raceway, the cross-sectional area of two raceways is gradually reduced in the direction from outer ring to inner ring, several conical rollers are respectively arranged in first raceway and second raceway, the taper angle of conical roller arranged in first raceway is different from that of conical roller arranged in second raceway.The wind turbine includes the variable pitch bearing as above. The above structure effectively eliminates abnormal wear caused by sliding, significantly reduces the stress concentration of the contact surface, thereby greatly prolongs the service life of the raceway and the roller, and enhances the operation reliability of the variable pitch bearing under long-term high load conditions.

Description

Technical Field

[0001] This utility model relates to the field of wind power generation technology, and in particular to a pitch bearing and a wind turbine generator including the same. Background Technology

[0002] The pitch bearing of a wind turbine is a core component connecting the hub and blades. It typically consists of an inner ring, an outer ring, and rolling elements positioned between the raceways of the inner and outer rings. The core function of the pitch bearing is to precisely adjust the blade pitch angle by driving the inner or outer rings to rotate relative to each other, thereby changing the windward angle and controlling the turbine's power and load. Its performance and reliability directly affect the overall power generation efficiency, stability, and safe lifespan of the wind turbine.

[0003] Currently, pitch bearings in high-power wind turbines mostly employ cylindrical roller bearing structures. However, because the inner and outer raceways are parallel cylindrical surfaces, their radii of rotation inherently differ. When the inner ring rotates, the linear velocities at the contact points between the inner and outer rings and the rollers are different, while the cylindrical roller as a whole can only rotate at one angular velocity. This makes it impossible for it to simultaneously match the velocities of the inner and outer rings, creating an irreconcilable geometric contradiction, ultimately leading to harmful forced relative slippage between the rollers and the raceways.

[0004] The aforementioned sliding wear caused by misalignment of the rotation center is significantly harmful. It not only induces abnormal abrasive wear and fatigue spalling on the contact surfaces of the rollers and raceways, drastically reducing the rated life and reliability of the bearing, but also leads to abnormal temperature rise due to increased friction, worsening lubrication conditions. Over the long term, this will cause increased bearing clearance, decreased control accuracy, abnormal operating noise, and may even lead to bearing jamming or sudden failure, affecting the stable operation and safety of the wind turbine. Utility Model Content

[0005] The technical problem to be solved by this utility model is to overcome the defect in the prior art that cylindrical rollers are prone to sliding wear between the rollers and the raceway due to the difference in the center of rotation, and to provide a pitch bearing and a wind turbine unit including the same.

[0006] The present invention solves the above-mentioned technical problems through the following technical solution:

[0007] This utility model provides a pitch bearing, which includes an inner ring, an outer ring sleeved outside the inner ring, and a plurality of tapered rollers. The inner side of the outer ring is recessed along its circumferential direction toward the radial direction of the outer ring to form a first cavity. The outer side of the inner ring is protruded along its circumferential direction toward the radial direction of the outer ring to form a boss. The boss extends into the first cavity to divide the first cavity into a first raceway and a second raceway along the axial direction of the outer ring. The cross-sectional areas of the first raceway and the second raceway gradually decrease in the direction from the outer ring toward the inner ring. The plurality of tapered rollers are respectively disposed in the first raceway and the second raceway along the circumferential direction of the outer ring. The rotation axes of the tapered rollers are parallel to each other and parallel to the radial direction of the outer ring.

[0008] In this design, the pitch bearing forms a tapered raceway through the engagement of the first cavity and the boss, creating a stable line contact between the tapered rollers and the raceway. This effectively avoids the forced sliding friction caused by the difference in radii of rotation of cylindrical roller bearings when the inner and outer rings rotate relative to each other. This structure effectively eliminates abnormal wear caused by sliding, significantly reduces stress concentration on the contact surfaces, thereby greatly extending the service life of the raceway and rollers and enhancing the operational reliability of the pitch bearing under long-term high-load conditions.

[0009] Preferably, the first raceway is close to the blade, the second raceway is close to the hub, the cone angle of the tapered roller in the first raceway is α1, the cone angle of the tapered roller in the second raceway is α2, and α1 is greater than or equal to α2.

[0010] In this design, the cone angles of the tapered rollers in the two raceways can be the same or different. When the two cone angles are the same, even load distribution is achieved, preventing overload of any single roller in the raceway. Furthermore, the reason for the different cone angles is that the axial load is larger on the side closer to the blade, while the radial load is larger on the side closer to the hub. The tapered rollers in the first raceway closer to the blade are designed with a larger cone angle to primarily bear the axial load; the tapered rollers in the second raceway closer to the hub are designed with a smaller cone angle to better resist the radial load. Through this arrangement, the structural characteristics of the rollers on both sides are matched to the stress characteristics of their respective positions, thereby significantly improving the reliability of the pitch bearing under complex loads.

[0011] Preferably, the outer ring further includes at least two flanges, which are respectively disposed in the first raceway and the second raceway. One end of each flange is fixedly connected to the inner wall of the first cavity, and the other end of each flange abuts against the end face of the tapered roller facing the outer ring along the radial direction of the outer ring. The surface of the flange abutting against the tapered roller and the end face of the tapered roller facing the outer ring are both spherical surfaces.

[0012] In this solution, the above settings allow the contact points between the flange and the tapered roller to move freely in three dimensions. This ensures that when the pitch bearing is subjected to dynamic loads that cause the rollers to tilt, the optimal surface contact state can be maintained, effectively dispersing and significantly reducing contact stress, thereby reducing the roller tilt angle and lowering the risk of failure under extreme conditions.

[0013] Preferably, the two flanges are respectively offset from the axis of rotation of the tapered roller and abut against one side of the spherical surface of the tapered roller; and / or, the two flanges are symmetrically arranged with respect to the boss.

[0014] In this design, since the closer the flange is to the center of the spherical surface of the tapered roller, the less capable the flange is of adapting to bearing deformation under load. Therefore, the flange needs to be offset to one side of the axis of rotation of the tapered roller. In addition, symmetrical arrangement of the two flanges can make the movement of the tapered rollers in the two raceways more stable.

[0015] Preferably, the wall surface of the first cavity facing the inner ring is a bottom wall, a gap is provided between the boss and the bottom wall to connect the first raceway and the second raceway, and the outer ring is provided with an oil inlet and an oil outlet, the oil inlet being connected to the first raceway and the oil outlet being connected to the second raceway.

[0016] In this design, since the first and second raceways are connected, lubricating oil can be added to both raceways simultaneously using a single oil inlet by setting oil inlets and outlets on the first and second raceways respectively. This structure makes the lubrication operation more convenient.

[0017] Preferably, the walls on both sides of the bottom wall are sidewalls, and at least one oil groove is provided in the first cavity, the oil groove being recessed from the connection between the bottom wall and the sidewall in a direction away from the conical roller.

[0018] In this solution, the oil groove is recessed inward to form a cavity to accommodate lubricating oil. When the amount of lubricating oil in the raceway decreases, the lubricating oil stored in the oil groove will be automatically replenished to the raceway, thereby reducing the frequency of lubricating oil replenishment and reducing maintenance costs.

[0019] Preferably, the wall surface of the first cavity facing the inner ring is the bottom wall, the boss is recessed inward along the radial direction of the outer ring to form a second cavity, a third raceway is formed between the bottom wall of the second cavity and the first cavity, and the pitch bearing further includes cylindrical rollers, which are matched with the third raceway and disposed within the third raceway.

[0020] In this design, by setting a third raceway and cylindrical rollers, the cylindrical rollers directly contact and roll relative to the bottom wall of the first cavity, while the tapered rollers can bear the radial load of the pitch bearing, further improving the pitch bearing's ability to bear radial loads and further reducing the risk of the tapered rollers tilting.

[0021] Preferably, the outer ring is divided into a first ring body and a second ring body along its own axial direction, the first ring body and the second ring body are detachably connected, and the projection of the connection between the first ring body and the second ring body along the radial direction of the outer ring falls into the first cavity.

[0022] In this design, due to the high precision of the pitch bearing, the fit clearance between the inner and outer rings, as well as between the tapered rollers and the two raceways, is very small. By setting a split outer ring, the tapered rollers are first installed on the first and second outer rings respectively, and then the first and second outer rings are installed on the inner ring, thus achieving convenient installation and avoiding interference between the various structures during installation.

[0023] Preferably, the ratio of the axial length of the tapered roller to its radial length is in the range of 1-2.

[0024] In this solution, by increasing the axial length of the tapered rollers, the contact area between the tapered rollers and the inner wall of the raceway is increased, thereby improving the axial load capacity of the pitch bearing and enhancing its adaptability under high axial load conditions.

[0025] This utility model also provides a wind turbine generator set, which includes the pitch bearing described in any of the above technical solutions.

[0026] The positive and progressive effects of this utility model are as follows:

[0027] This utility model provides a pitch bearing and a wind turbine unit including the same. The pitch bearing forms a gradually narrowing raceway through the cooperation of a first concave cavity and a boss, creating stable line contact between the tapered rollers and the raceway. This effectively avoids the forced sliding friction caused by the difference in radii of rotation of cylindrical roller bearings when the inner and outer rings rotate relative to each other. This structure effectively eliminates abnormal wear caused by sliding, significantly reduces stress concentration on the contact surfaces, thereby greatly extending the service life of the raceway and rollers, and enhancing the operational reliability of the pitch bearing under long-term high-load conditions. Attached Figure Description

[0028] Figure 1 This is a perspective view of the pitch bearing according to an embodiment of the present utility model.

[0029] Figure 2 This is a front view of the inner ring of an embodiment of this utility model.

[0030] Figure 3 This is a cross-sectional view of the outer ring of an embodiment of the present invention.

[0031] Figure 4 This is a cross-sectional view of the pitch bearing according to an embodiment of the present invention.

[0032] Figure 5 for Figure 4 One of the schematic diagrams of the cross-sectional structure of region A in the middle.

[0033] Figure 6 for Figure 4 The second schematic diagram of the cross-sectional structure of region A in the middle.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1000 pitch bearing

[0036] Inner circle 1

[0037] 101 convex surface

[0038] Second cavity 102

[0039] Third Roller Rail 103

[0040] Outer ring 2

[0041] First cavity 201

[0042] Edge band 202

[0043] First circumference 203

[0044] Second ring 204

[0045] Tapered roller 3

[0046] First Rolling Track 4

[0047] Second Roller 5

[0048] Oil inlet 6

[0049] Oil outlet 7

[0050] Oil Ditch 8

[0051] Cylindrical roller 9 Detailed Implementation

[0052] The present invention will be described more clearly and completely below with reference to the accompanying drawings, using a preferred embodiment.

[0053] Example 1.

[0054] like Figures 1 to 6As shown, this embodiment provides a pitch bearing 1000, which includes an inner ring 1, an outer ring 2 sleeved outside the inner ring 1, and a plurality of tapered rollers 3. The outer ring 2 is disposed in a hub, and the blades are connected to the inner ring 1. The inner ring 1 rotates relative to the outer ring 2, thereby changing the angle of the blades. A first cavity 201 is formed by a recess on the inward side of the outer ring 2 along its circumferential direction towards the radial direction of the outer ring 2. Figure 3 As shown, the cross-sectional shape of one side of outer ring 2 is a sideways U-shape. (As...) Figure 2 As shown, the outer side of the inner ring 1 protrudes radially towards the outer ring 2 along its circumferential direction to form a boss 101. The boss 101 extends into the first cavity 201 to divide the first cavity 201 into a first raceway 4 and a second raceway 5 along the axial direction of the outer ring 2. That is, the first raceway 4 and the second raceway 5 are vertically related along the axial direction of the pitch bearing 1000. The cross-sectional areas of the first raceway 4 and the second raceway 5 gradually decrease from the outer ring 2 towards the inner ring 1, making the cross-sectional shape of the two raceways conical. Several conical rollers 3 are respectively arranged in the first raceway 4 and the second raceway 5 along the circumference of the outer ring 2. The conical rollers 3 are arranged with the larger diameter end facing outward and the smaller diameter end facing inward, and are spaced apart. The conical surfaces of the first raceway 4 and the second raceway 5 converge at the same point on the axis of the conical rollers 3. The rotation axes of the conical rollers 3 are parallel to each other and parallel to the radial direction of the outer ring 2.

[0055] Thus, the pitch bearing 1000 forms a raceway with a gradually narrowing cross-section through the cooperation of the first cavity 201 and the boss 101, enabling stable line contact between the tapered roller 3 and the raceway. This effectively avoids forced sliding friction caused by the difference in the radii of rotation of cylindrical roller bearings when the inner and outer rings rotate relative to each other. The above structure effectively eliminates abnormal wear caused by sliding, significantly reduces stress concentration on the contact surface, thereby greatly extending the service life of the two raceways and the tapered roller 3, and enhancing the operational reliability of the pitch bearing 1000 under long-term high-load conditions.

[0056] In this embodiment, the tapered rollers 3 located in the first raceway 4 and the tapered rollers 3 located in the second raceway 5 have different cone angles, where the cone angle refers to the included angle between the generatrices of the two sides of the tapered roller 3. In other embodiments, the tapered rollers 3 located in the first raceway 4 and the tapered rollers 3 located in the second raceway 5 may have the same cone angle. When the two cone angles are the same, uniform load distribution can be achieved, avoiding overload of the rollers in a single raceway.

[0057] Thus, the pitch bearing 1000 divides the first cavity 201 of the outer ring 2 into two raceways through the boss 101 of the inner ring 1. The cross-sectional area of ​​the raceways gradually decreases along the direction from the outer ring 2 to the inner ring 1, i.e., towards the axis of the pitch bearing 1000, making the raceways and the mounted rollers conical. The conical surfaces of the conical rollers 3 and the extended lines of the conical surfaces of the raceways converge at the same point on the roller axis. This ensures that the linear velocity of the rollers at the contact points with the inner and outer rings 2 remains consistent at all times, achieving true pure rolling. Therefore, it fundamentally eliminates the forced sliding caused by the difference in rotational center of the cylindrical rollers, overcoming the resulting sliding wear defects. The larger diameter end of the conical roller 3 is closer to the outer side of the variable diameter bearing, thus being closer to the load concentrated at the edge of the pitch bearing 1000, and therefore more effectively bearing the load. Meanwhile, the cone angle of the tapered roller 3 will affect the amount of axial or radial load that the roller can bear. Using tapered rollers 3 with different cone angles can optimize the load distribution, reduce the working tilt angle of the roller and the contact stress with the raceway, and improve the anti-overturning ability and fatigue life of the pitch bearing 1000.

[0058] In this embodiment, the first raceway 4 is located near the root of the blade, i.e., as shown below. Figure 5 The upper middle raceway. The second raceway 5 is close to the wheel hub, i.e. Figure 5 The raceway at the bottom center. The cone angle of the tapered roller 3 set in the first raceway 4 is α1, and the cone angle of the tapered roller 3 set in the second raceway 5 is α2, where α1 > α2.

[0059] Thus, since the axial load is larger on the side closer to the blade and the radial load is larger on the side closer to the hub, the tapered roller 3 in the first raceway 4 near the blade is designed with a large cone angle to primarily bear the axial load. The tapered roller 3 in the second raceway 5 near the hub is designed with a small cone angle to better suit resisting the radial load. Through this arrangement, the traditional symmetrical load is transformed into an asymmetrical load, matching the structural characteristics of the rollers on both sides with the force characteristics of their respective positions, thereby significantly improving the reliability of the pitch bearing 1000 under complex loads.

[0060] Furthermore, the extension lines of the two raceway tapered surfaces of the pitch bearing 1000 are both focused on the central axis of the pitch bearing 1000 to avoid back-and-forth swaying during operation and reduce the impact on the inner and outer rings 2, so as to adapt to independent pitch motion.

[0061] Specifically, such as Figure 5As shown, the outer ring 2 also includes at least two retaining edges 202, which are respectively disposed within the first raceway 4 and the second raceway 5. One end of each retaining edge 202 is fixedly connected to the inner wall of the first cavity 201, and the other end of each retaining edge 202 abuts against the end face of the tapered roller 3 facing the outer ring 2 along the radial direction of the outer ring. The point where the retaining edge 202 contacts the tapered roller 3 is the contact point, which bears the radial load of the tapered roller 3 and prevents the tapered roller 3 from moving radially. Therefore, in order to improve the service life of the retaining edge 202, it is necessary to perform quenching treatment on the retaining edge 202. This can improve the wear resistance of the retaining edge 202, thereby improving its service life.

[0062] Furthermore, the surface where the flange 202 abuts against the tapered roller 3, as well as the end face of the tapered roller 3 facing the outer ring 2, are both spherical surfaces. The diameter of the spherical surface of the tapered roller 3 is the diameter of the roller's rotation center, to accommodate the deformation of the inner ring 1 or outer ring 2 when the pitch bearing 1000 is under load, reducing the tilt angle of the tapered roller 3 caused by deformation. Specifically, through the above arrangement, since the contact between the end faces of the flange 202 and the tapered roller 3 is a spherical surface, this allows the contact point between the flange 202 and the tapered roller 3 to move freely on the spherical surface, i.e., in three dimensions. When the pitch bearing 1000 is subjected to dynamic loads that cause the rollers to tilt, it can continuously maintain the optimal surface contact state, effectively disperse and significantly reduce contact stress, thereby reducing the roller tilt angle and reducing the risk of failure under extreme operating conditions.

[0063] Specifically, the first raceway 4 is close to the blade, the second raceway 5 is close to the hub, the diameter of the spherical surface of the flange 202 of the first raceway 4 is R1, and the diameter of the spherical surface of the flange 202 of the second raceway 5 is R2, where R1 < R2.

[0064] Thus, since the tapered roller 3 near the blade mainly bears the axial load, the radial load it bears is relatively small, and the contact stress on the flange 202 is also relatively small. Therefore, the spherical surface of the flange 202 located in the first raceway 4 can have a smaller diameter, making the contact point between the flange 202 and the tapered roller 3 more precise. The tapered roller 3 near the hub mainly bears the radial load, and the contact stress on the flange 202 is also relatively large, making it more prone to tilting. Therefore, the spherical surface of the flange 202 located in the second raceway 5 uses a larger diameter, allowing the contact point to smoothly migrate on the spherical surface with a large radius of curvature. This also allows for a larger tilting angle for the tapered roller 3, which helps avoid localized stress concentration at the contact point.

[0065] Furthermore, the two flanges 202 are respectively offset from the rotation axis of the tapered rollers 3 in the two raceways, and respectively abut against the spherical surfaces of the two tapered rollers 3. Since the flange 202 has a smaller ability to adapt to bearing deformation under load the closer it is to the center of the spherical surface of the tapered roller 3, it is necessary to offset the flange 202 to one side of the rotation axis of the tapered roller 3. Specifically, the above effect can be achieved simply by not setting the flange on the rotation axis of the tapered roller 3. Preferably, in this embodiment, the two flanges 202 are respectively set on the side of the two tapered rollers 3 that are far apart from each other. In other embodiments, the two flanges 202 may also be offset towards the same side, or they may be respectively set on the side of the two tapered rollers 3 that are close to each other.

[0066] Furthermore, such as Figure 5 As shown, the two flanges 202 are symmetrically arranged relative to the boss 101. The symmetrical arrangement of the two flanges 202 can make the movement of the tapered rollers 3 in the two raceways more stable.

[0067] Specifically, such as Figure 5 As shown, the wall of the first cavity 201 facing the inner ring 1 is the bottom wall. A gap is provided between the boss 101 and the bottom wall to connect the first raceway 4 and the second raceway 5. The outer ring 2 is provided with an oil inlet 6 and an oil outlet 7. The oil inlet 6 connects to the first raceway 4, and the oil outlet 7 connects to the second raceway 5. Thus, since the first raceway 4 and the second raceway 5 are connected, lubricating oil can be added to both raceways simultaneously using one oil inlet 6 by providing the oil inlet 6 and the oil outlet 7 respectively. This structure makes the lubrication operation more convenient.

[0068] Furthermore, the walls on both sides of the bottom wall are sidewalls, and at least one oil groove 8 is provided in the first cavity 201. The oil groove 8 is recessed from the connection between the bottom wall and the sidewall in a direction away from the tapered roller 3. In this embodiment, as... Figure 5 As shown, a recessed oil groove 8 is provided at the corner of the first raceway 4 and the second raceway 5, respectively. With the above arrangement, the inward recess of the oil groove 8 can form a cavity to accommodate lubricating oil. When the amount of lubricating oil in the raceway decreases, the lubricating oil stored in the oil groove 8 will be automatically replenished to the raceway, thereby reducing the frequency of lubricating oil replenishment and reducing maintenance costs.

[0069] Specifically, such as Figure 3 and Figure 5As shown, the outer ring 2 is divided into a first ring body 203 and a second ring body 204 along its own axial direction. The first ring body 203 and the second ring body 204 are stacked vertically along their own axial direction to form a complete outer ring 2. The first ring body 203 and the second ring body 204 are detachably connected. In this embodiment, the first ring body 203 and the second ring body 204 are connected by bolts. In other embodiments, other existing detachable connection methods can also be used. The projection of the connection point of the first ring body 203 and the second ring body 204 along the radial direction of the outer ring 2 falls within the first cavity 201. That is, the dividing line between the first outer ring 2 and the second outer ring 2 can separate the first cavity 201, so that the first cavity 201 is also divided into two parts along with the separation of the first outer ring 2 and the second outer ring 2. Thus, due to the high precision of the pitch bearing 1000, the fit clearance between the inner ring 1 and the outer ring 2, as well as between the tapered roller 3 and the two raceways, is very small. By setting a split outer ring 2, tapered rollers 3 are first installed on the first outer ring 2 and the second outer ring 2 respectively, and then the first outer ring 2 and the second outer ring 2 are installed on the inner ring 1, thus achieving convenient installation and avoiding interference between the various structures during installation. Alternatively, the tapered rollers 3 can be installed on the inner ring 1 first, and then the first outer ring 2 and the second outer ring 2 can be installed on the inner ring 1.

[0070] Specifically, such as Figure 6 As shown, the axial length of the tapered roller 3 is Lw, and the radial length of the tapered roller 3 is Dp. Wherein, Lw > Dp, and preferably, the ratio of Lw / Dp ranges from 1 to 2. Thus, by increasing the axial length of the tapered roller 3, the contact area between the tapered roller 3 and the inner wall of the raceway is increased, thereby improving the axial load capacity of the pitch bearing 1000 and enhancing its adaptability under high axial load conditions.

[0071] Example 2.

[0072] The difference between this embodiment and Embodiment 1 is that a cylindrical roller 9, which mainly bears the radial load, is added.

[0073] like Figure 5 As shown, a second cavity 102 is formed by recessing the boss 101 inward along the radial direction of the outer ring 2. A third raceway 103 is formed between the second cavity 102 and the bottom wall of the first cavity 201. The pitch bearing 1000 also includes cylindrical rollers 9. The cylindrical rollers 9 are matched with and disposed within the third raceway 103. Thus, by providing the third raceway 103 and the cylindrical rollers 9, the cylindrical rollers 9 directly contact and roll relative to the bottom wall of the first cavity 201, and the tapered rollers 3 can bear the radial load of the pitch bearing 1000, further improving the radial load bearing capacity of the pitch bearing 1000 and further reducing the risk of the tapered rollers 3 tilting.

[0074] Example 3.

[0075] This embodiment provides a wind turbine generator set, which includes a pitch bearing 1000 as in Embodiment 1 or 2.

[0076] The advantages of this wind turbine are:

[0077] 1. Avoiding the relative sliding between the rollers and raceways caused by the difference in the center of rotation of cylindrical roller bearings can effectively solve the problem of the short service life of pitch bearing 1000 caused by the relative sliding between the rollers and raceways, and significantly extend the service life of pitch bearing 1000.

[0078] 2. By breaking the limitation of the Lw / Dp ratio and increasing Lw, the contact area between the tapered roller 3 and the inner wall of the raceway is increased, thereby improving the axial load capacity of the pitch bearing 1000 and enhancing its adaptability under high axial load conditions.

[0079] 3. For bearings with the same external dimensions, increasing Lw can increase the axial bending moment that the bearing as a whole can withstand;

[0080] 4. The tapered roller 3 can share part of the radial load; depending on the situation, it may be necessary to select whether the cylindrical roller 9 is needed.

[0081] 5. During operation, this pitch bearing 1000 can reduce the impact of the tapered rollers 3 on the inner wall of the raceway, and avoid bearing failure caused by the breakage of the inner and outer rings 2.

[0082] 6. The tapered rollers 3 have no relative sliding, and the rollers in each raceway move in a highly coordinated manner. The cage can be designed with multiple raceways. By reducing the deviation of the roller running trajectory in each raceway, the problem of easy breakage of the inner and outer rings 2 of the pitch bearing 1000 is solved.

[0083] While specific embodiments of this utility model have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this utility model, but all such changes and modifications fall within the scope of protection of this utility model.

Claims

1. A pitch bearing, characterized in that, The pitch bearing includes an inner ring, an outer ring fitted outside the inner ring, and a plurality of tapered rollers. The inner side of the outer ring is recessed along its circumferential direction toward the radial direction of the outer ring to form a first cavity. The outer side of the inner ring protrudes along its circumferential direction toward the radial direction of the outer ring to form a boss. The boss extends into the first cavity to divide the first cavity into a first raceway and a second raceway along the axial direction of the outer ring. The cross-sectional areas of the first raceway and the second raceway gradually decrease in the direction from the outer ring toward the inner ring. The plurality of tapered rollers are respectively disposed in the first raceway and the second raceway along the circumferential direction of the outer ring. The rotation axes of the tapered rollers are parallel to each other and parallel to the radial direction of the outer ring.

2. The pitch bearing as described in claim 1, characterized in that, The first raceway is close to the blade, and the second raceway is close to the hub. The cone angle of the tapered roller in the first raceway is α1, and the cone angle of the tapered roller in the second raceway is α2, and α1 is greater than or equal to α2.

3. The pitch bearing as described in claim 1, characterized in that, The outer ring also includes at least two retaining edges, which are respectively disposed in the first raceway and the second raceway. One end of the retaining edge is fixedly connected to the inner wall of the first cavity, and the other end of the retaining edge abuts against the end face of the tapered roller facing the outer ring along the radial direction of the outer ring. The surface of the retaining edge abutting against the tapered roller and the end face of the tapered roller facing the outer ring are both spherical surfaces.

4. The pitch bearing as described in claim 3, characterized in that, The two flanges are offset from the axis of rotation of the tapered rollers and respectively abut against the spherical surfaces of the two tapered rollers; And / or, the two said flanges are symmetrically arranged with respect to the said boss.

5. The pitch bearing as described in claim 1, characterized in that, The wall surface of the first cavity facing the inner ring is the bottom wall. A gap is provided between the boss and the bottom wall to connect the first raceway and the second raceway. The outer ring is provided with an oil inlet and an oil outlet. The oil inlet is connected to the first raceway, and the oil outlet is connected to the second raceway.

6. The pitch bearing as described in claim 5, characterized in that, The walls on both sides of the bottom wall are sidewalls, and at least one oil groove is provided in the first cavity. The oil groove is recessed from the connection between the bottom wall and the sidewall in a direction away from the conical roller.

7. The pitch bearing as claimed in claim 1, characterized in that, The wall of the first cavity facing the inner ring is the bottom wall. The boss is recessed inward along the radial direction of the outer ring to form a second cavity. A third raceway is formed between the bottom wall of the second cavity and the first cavity. The pitch bearing also includes cylindrical rollers, which are matched with the third raceway and disposed within the third raceway.

8. The pitch bearing as claimed in claim 1, characterized in that, The outer ring is divided into a first ring body and a second ring body along its own axial direction. The first ring body and the second ring body are detachably connected. The projection of the connection between the first ring body and the second ring body along the radial direction of the outer ring body falls into the first cavity.

9. The pitch bearing as claimed in claim 1, characterized in that, The ratio of the axial length of the tapered roller to its radial length is in the range of 1-2.

10. A wind turbine generator set, characterized in that, The wind turbine includes a pitch bearing as described in any one of claims 1-9.

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