Wind power variable pitch speed reducer and design method thereof

Abstract

A wind power variable pitch speed reducer comprises a box body, an input shaft assembled in the box body, a multi-stage planetary speed reduction assembly assembled in the box body and meshed with the input shaft and an output shaft meshed with the output end of the multi-stage planetary speed reduction assembly, and the output shaft extends out of the box body. The speed reducer is characterized in that a plurality of rows of balls which are distributed in a plurality of rows from top to bottom in the axial direction are arranged between the output shaft and the box body, the output shaft is axially positioned on the box body through the plurality of rows of balls, and rotating connection between the output shaft and the box body is formed; a multi-layer sealing assembly is assembled between the output shaft and the box body, separates the multi-stage planetary speed reduction assembly from the multiple rows of balls in a sealed mode and seals the bottom end of the box body. The size of the output end of the variable-pitch speed reducer can be effectively reduced, the bearing capacity and supporting rigidity of the output shaft are improved, overturning is prevented, the abrasion rate of gears and bearings in the variable-pitch speed reducer is reduced, the service life is prolonged, and the sealing effect of the output end of the speed reducer is improved. The invention further provides a design method of the wind power variable pitch speed reducer.

Description

Technical Field

[0001] The invention relates to a wind turbine pitch-changing reducer, belonging to the technical field of wind turbine pitch-changing reducers. Background Art

[0002] In a wind turbine generator set, the variable pitch system plays a key role in adjusting the blade angle of the wind rotor and ensuring the stable and efficient operation of the unit at different wind speeds. The variable pitch reducer is a key transmission component in the variable pitch system. It converts the high speed and low torque of the drive motor into the low speed and high torque of the drive blade root bearing to adjust the direction and angle of the wind turbine blades. At present, variable pitch reducers mostly use multi-stage planetary gear transmission. The output shaft is connected to the unstage planetary carrier. Double spherical roller bearings or double tapered roller bearings are arranged on the output shaft to form the support between the output shaft and the reducer housing. The axial positioning of the output shaft is achieved by the cooperation of the round nut and the roller bearing fastened on the output shaft. The transmission characteristics of the output shaft are low speed and high torque, which requires the output shaft and the roller bearing to bear axial and radial loads. The support and positioning structure of the output shaft has the following defects: 1. The axial and radial dimensions of roller bearings are large, and they occupy a large space in the wind rotor hub. They have high requirements for the hub assembly space and poor adaptability. In addition, the roller bearings need to adjust the clearance to ensure that the bearings reach the best working state. The processing and assembly requirements are high, resulting in the output end of the variable pitch reducer being larger in size and the assembly cost being high.

[0003] 2. Roller bearings have high lubrication requirements, and the seal between the output end and the housing is weak. Iron filings formed by the wear of multi-stage planetary gears during operation can easily enter the upper roller bearings, affecting the performance and service life of the roller bearings. The reducer also has the risk of oil leakage.

[0004] 3. Under harsh working conditions, the reducer is prone to shaking, and the output shaft diameter and axial load increase, resulting in deviation. Due to insufficient load-bearing capacity, the output shaft will produce bending deformation and axial impact, which will affect the multi-stage planetary gears inside the reducer, accelerate the wear of the gears, reduce the stability of the reducer, and even cause the reducer to overturn.

[0005] 4. The tightening torque of the round nut needs to be above 2500Nm, which requires special high-torque tightening tools and equipment. In addition, there is a risk of the tightened round nut loosening during the operation of the reducer. If the round nut is loose, it will move axially on the output shaft, affecting the stability of the axial positioning of the output shaft. Summary of the invention

[0006] The wind turbine variable pitch reducer provided by the present invention can effectively reduce the size of the output end of the variable pitch reducer, improve the adaptability of the output end of the variable pitch reducer and the impeller hub, improve the load-bearing capacity and support stiffness of the output shaft, improve the stability of the variable pitch reducer, prevent overturning, improve the axial positioning reliability of the output shaft, reduce the wear rate of the internal gears and bearings of the variable pitch reducer, extend the service life, improve the sealing effect of the output end of the reducer, and ensure the lubrication reliability of the multi-row reduction assembly and the multi-row ball bearings. The present invention also provides a design method for a wind turbine variable pitch reducer.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is: A wind turbine variable pitch reducer comprises a housing, an input shaft mounted in the housing, a multi-stage planetary reduction assembly mounted in the housing and meshing with the input shaft, and an output shaft meshing with the output end of the multi-stage planetary reduction assembly, wherein the output shaft extends from the housing and is characterized in that: a plurality of rows of balls distributed in a plurality of rows axially from top to bottom are arranged between the output shaft and the housing, the plurality of rows of balls axially position the output shaft on the housing and form a rotational connection between the output shaft and the housing, and a multi-layer sealing assembly is arranged between the output shaft and the housing to seal the multi-stage planetary reduction assembly and the plurality of rows of balls and seal the bottom end of the housing.

[0008] Preferably, the multi-stage planetary reduction assembly includes a first-stage sun gear meshed with the input shaft, a first-stage planetary gear meshed with the first-stage sun gear, a first-stage planetary carrier connected to the first-stage planetary gear, a second-stage sun gear meshed with the first-stage planetary carrier, a second-stage planetary gear meshed with the second-stage sun gear, a second-stage planetary carrier connected to the second-stage planetary gear, a last-stage sun gear meshed with the second-stage planetary carrier, a last-stage planetary gear meshed with the last-stage sun gear, and a last-stage planetary carrier connected to the last-stage planetary gear, the first-stage planetary gear, the second-stage planetary gear and the last-stage planetary gear are respectively meshed with the ring gear on the inner wall of the casing, the upper end of the output shaft is meshed with the last-stage planetary carrier, and a multi-row ball bearing and a multi-layer sealing assembly are arranged below the last-stage planetary carrier.

[0009] Preferably, the output shaft is integrally formed from top to bottom by an upper gear section meshing with the final planetary carrier, an intermediate mating section and a lower gear section extending out of the housing, multiple rows of balls and a multi-layer sealing assembly are arranged between the inner wall of the housing and the intermediate mating section, an annular raceway is formed between the intermediate mating section and the inner wall of the housing, the annular raceway is evenly spaced along the axial direction, the multiple rows of balls are composed of balls installed in the annular raceway, the balls in the annular raceway are arranged in sequence to form a row of balls, and each ball forms four contact points with the annular raceway in a rectangular distribution.

[0010] Preferably, an inner wall raceway is provided on the inner wall of the box body, an output shaft raceway corresponding to the inner wall raceway is provided on the middle mating shaft, a radial gap is provided between the middle mating section and the inner wall of the box body so that the inner wall raceway and the corresponding output shaft raceway are separated and do not contact each other, the inner wall raceway and the corresponding output shaft raceway are radially aligned to form an annular raceway, the ball is sandwiched between the inner wall raceway and the corresponding output shaft raceway, and the ball forms two contact points with the inner wall raceway and the output shaft raceway respectively.

[0011] Preferably, the inner wall raceway and the output shaft raceway are both formed by connecting two annular arc surfaces with arc-shaped cross sections, and the two annular arc surfaces form point contacts with the balls respectively.

[0012] Preferably, the multi-layer sealing assembly comprises at least an upper oil seal disposed above the multiple rows of balls and a lower oil seal disposed below the multiple rows of balls.

[0013] Preferably, the inner cavity of the box body is divided into an upper cavity located above the upper oil seal and a lower cavity located between the upper oil seal and the lower oil seal, the upper cavity is filled with lubricating oil for lubricating the multi-stage planetary reduction assembly, and the lower cavity is injected with grease for lubricating the multiple rows of balls.

[0014] Preferably, the housing is composed of an upper housing and a lower housing coaxially fixed to the bottom of the upper housing, a plurality of rows of balls and a multi-layer sealing assembly are respectively installed between the lower housing and the output shaft, the inner cavity of the lower housing includes a gear ring cavity meshing with the final planetary gear, an assembly cavity for assembling the plurality of rows of balls and the multi-layer sealing assembly, and a wedge-shaped transition cavity arranged between the gear ring cavity and the assembly cavity, the inner diameter of the assembly cavity is smaller than the inner diameter of the gear ring cavity, the wedge-shaped transition cavity is wedge-shaped with a diameter gradually decreasing from top to bottom, an upper annular step surface matching with the upper oil seal is arranged at the top of the assembly cavity, a lower annular step surface matching with the lower oil seal is arranged at the bottom of the assembly cavity, the upper oil seal abuts against the upper annular step surface, the lower oil seal abuts against the lower annular step surface, and an axial retaining ring for supporting the lower oil seal is arranged in the assembly cavity.

[0015] The design method of the wind turbine variable pitch reducer described above is characterized in that the number of rows of balls, the ball diameter and the number of balls in each row are designed according to the radial load, axial load and torque transmission requirements of the output shaft.

[0016] Preferably, the number of layers of the multi-layer sealing assembly and the axial position of each layer are designed according to the number of rows of multi-row balls, lubrication requirements and sealing requirements of the box.

[0017] The beneficial effects of the invention are: The wind turbine variable pitch reducer of the present invention is equipped with multiple rows of balls between the output shaft and the housing. The multiple rows of balls axially position the output shaft on the housing and form a rotational connection between the output shaft and the housing. The multiple rows of balls replace the roller bearings between the housing and the output shaft in the prior art. The axial and radial dimensions occupied by the multiple rows of balls between the output shaft and the housing are small, which can effectively reduce the size of the output end of the variable pitch reducer and improve the adaptability of the output end of the variable pitch reducer to the impeller hub.

[0018] The number of rows of multi-row balls, the ball diameter and the number of balls in each row can be set according to the load-bearing requirements of the output shaft, so as to improve the load-bearing capacity and support stiffness of the output shaft, adapt to the load-bearing requirements of harsh working conditions, ensure that the output shaft is not offset along the axial direction of the reducer, reduce the impact on the internal structure of the reducer, improve the stability of the variable pitch reducer, and prevent overturning.

[0019] The axial positioning of the output shaft on the housing is formed by multiple rows of balls, replacing the axial positioning structure of the round nut fastened to the output shaft. This not only saves the tightening operation of the round nut, but also improves the axial positioning reliability of the output shaft, reduces the impact of the output shaft on the multi-stage planetary reduction assembly during operation, reduces the wear rate of the internal gears and bearings of the variable pitch reducer, and extends the service life.

[0020] A multi-layer sealing component is installed between the output shaft and the housing. The multi-layer sealing component seals and separates the multi-stage planetary reduction component from the multi-row ball bearings and seals the bottom end of the housing. The chamber where the multi-stage planetary reduction component is located in the housing is sealed and separated from the chamber where the multi-row ball bearings are located. The multi-row ball bearings and the multi-row reduction component are lubricated separately and independently to prevent iron filings generated by gear wear during the operation of the multi-stage planetary reduction component from falling into the multi-stage ball bearings. The setting of the multi-layer sealing component improves the sealing effect of the output end of the reducer and ensures the lubrication reliability of the multi-row reduction component and the multi-row ball bearings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the wind turbine variable pitch reducer of the present invention.

[0022] Figure 2 for Figure 1 A partial enlarged schematic diagram of .

[0023] Figure 3 Schematic diagram of the output shaft.

[0024] Figure 4 Schematic diagram of the lower box. DETAILED DESCRIPTION

[0025] Combine the following Figures 1 to 4 The embodiments of the present invention are described in detail.

[0026] The wind turbine variable pitch reducer comprises a housing 1, an input shaft 2 mounted in the housing 1, a multi-stage planetary reduction assembly 3 mounted in the housing 1 and meshing with the input shaft 1, and an output shaft 4 meshing with the output end of the multi-stage planetary reduction assembly 3, wherein the output shaft 4 extends from the housing 1, and is characterized in that: a plurality of rows of balls 5 distributed in a plurality of rows axially from top to bottom are arranged between the output shaft 4 and the housing 1, the plurality of rows of balls 5 axially position the output shaft 4 on the housing 1 and form a rotational connection between the output shaft 4 and the housing 1, and a multi-layer sealing assembly 6 is arranged between the output shaft 4 and the housing 1 to seal and separate the multi-stage planetary reduction assembly 3 and the plurality of rows of balls 5 and to seal the bottom end of the housing 1.

[0027] The wind turbine variable pitch reducer described above is equipped with multiple rows of balls 5 between the output shaft 4 and the housing 1. The multiple rows of balls 5 axially position the output shaft 4 on the housing 1 and form a rotational connection between the output shaft 4 and the housing 1. The multiple rows of balls 5 replace the roller bearings between the housing and the output shaft in the prior art. The multiple rows of balls 5 have small axial and radial dimensions between the output shaft 4 and the housing 1, which can effectively reduce the size of the output end of the variable pitch reducer and improve the compatibility between the output end of the variable pitch reducer and the impeller hub. The number of rows of multiple rows of balls 5, the ball diameter and the number of balls in each row can be set according to the load requirements of the output shaft 4, so as to improve the load capacity and support stiffness of the output shaft, adapt to the load requirements of harsh working conditions, ensure that the output shaft is set along the axial direction of the reducer without deviation, reduce the impact on the internal structure of the reducer, improve the stability of the variable pitch reducer, and prevent overturning. The output shaft 4 is axially positioned on the housing 1 by using multiple rows of balls 5, replacing the axial positioning structure of the round nut fastened on the output shaft, which not only saves the fastening operation of the round nut, but also improves the reliability of the axial positioning of the output shaft 4, reduces the impact of the output shaft on the multi-stage planetary reduction assembly 3 during operation, reduces the wear rate of the internal gears and bearings of the variable pitch reducer, and prolongs the service life. A multi-layer sealing component 6 is installed between the output shaft 4 and the housing 1, and the multi-layer sealing component 6 seals and separates the multi-stage planetary reduction assembly 3 and the multiple rows of balls 5 and seals the bottom end of the housing 1, and seals and separates the chamber where the multi-stage planetary reduction assembly 3 in the housing 1 and the chamber where the multiple rows of balls 5 are located. The multiple rows of balls 5 and the multi-row reduction assembly 3 are separately lubricated independently to prevent iron filings generated by gear wear during the operation of the multi-stage planetary reduction assembly 3 from falling into the multi-stage balls 5. The setting of the multi-layer sealing component 6 improves the sealing effect of the output end of the reducer and ensures the lubrication reliability of the multi-row reduction assembly and the multiple rows of balls.

[0028] Among them, the multi-stage planetary reduction assembly 3 includes a primary sun gear 31 meshed with the input shaft 2, a primary planetary gear 32 meshed with the primary sun gear 31, a primary planet carrier 33 connected to the primary planetary gear 32, a secondary sun gear 34 meshed with the primary planetary gear 33, a secondary planetary gear 35 meshed with the secondary sun gear 34, a secondary planetary gear 36 connected to the secondary planetary gear 35, a final sun gear 37 meshed with the secondary planetary gear 36, a final planetary gear 38 meshed with the final sun gear 37 and a final planetary gear 39 connected to the final planetary gear 38, the primary planetary gear 32, the secondary planetary gear 35 and the final planetary gear 38 are respectively meshed with the ring gear on the inner wall of the casing 1, the upper end of the output shaft 4 is meshed with the final planetary gear 39, and a multi-row ball 5 and a multi-layer sealing assembly 6 are arranged below the final planetary gear 39. The multi-stage planetary reduction assembly 3 includes a three-stage planetary gear structure. The last-stage planet carrier 39 is located above the multi-row balls 5 and the multi-layer sealing assembly 6. The multi-row balls 5 and the multi-layer sealing assembly 6 are respectively assembled between the output shaft 4 and the inner wall of the casing 1. The multi-layer sealing assembly 6 seals the multi-stage planetary reduction assembly 3 from the multi-row balls 5, seals the chamber where the multi-row balls 5 are located, and forms a multi-layer seal on the bottom end of the casing 1, so that the multi-stage reduction assembly 3 and the multi-row balls 5 are separately lubricated, thereby improving the lubrication reliability and effectively reducing the risk of oil leakage.

[0029] Among them, the output shaft 4 is integrally formed from top to bottom by an upper gear section 41 meshing with the final planetary carrier 39, an intermediate matching section 42 and a lower gear section 43 extending out of the housing 1. Multiple rows of balls 5 and a multi-layer sealing assembly 6 are arranged between the inner wall of the housing 1 and the intermediate matching section 42. An annular raceway 7 is formed between the intermediate matching section 42 and the inner wall of the housing 1. The annular raceway 7 is evenly spaced along the axial direction. The multiple rows of balls 5 are composed of balls 51 installed in the annular raceway. The balls 51 in the annular raceway 7 are arranged in sequence to form a row of balls. Each ball 51 forms four contact points with the annular raceway 7 in a rectangular distribution. The annular raceway 7 is provided on the middle matching section 42 and the inner wall of the housing 1, and the middle matching section 42 and the housing 1 are used as the inner and outer sleeves of the bearing, and the inner and outer sleeves of the bearing are omitted. The assembly structure of the balls 51, the middle matching section 42 and the housing 1 replaces the bearing, and the weight and size of the assembly structure of the output shaft 4 and the housing 1 are reduced. The balls 51 and the annular raceway 7 form four contact points distributed in a rectangular shape, and the multi-row balls 5 are equivalent to multi-row four-point contact bearings. The multi-row balls 5 cooperate with the output shaft and the housing to form axial positioning and radial support for the output shaft 4, improve the positioning reliability and load-bearing capacity of the output shaft 4, improve the support stiffness and load-bearing capacity of the output shaft 4, and improve the anti-bending moment capacity of the output shaft 4, and effectively reduce the probability of bending moment deformation of the output shaft 4 under harsh working conditions. The balls 51 in the annular raceway 7 are arranged in sequence to form a row of balls, and there is no isolation block between adjacent balls 51. The balls 51 in the annular raceway 7 can be fully loaded, with more balls, simpler assembly, and higher load-bearing capacity.

[0030] Among them, the inner wall of the box body 1 is provided with an inner wall raceway A, the middle matching shaft 42 is provided with an output shaft raceway B corresponding to the inner wall raceway A one-to-one, and a radial gap C is provided between the middle matching section 42 and the inner wall of the box body 1 so that the inner wall raceway A and the corresponding output shaft raceway B are separated and do not contact each other, the inner wall raceway A and the corresponding output shaft raceway B are radially aligned to form an annular raceway 7, the ball 51 is sandwiched between the inner wall raceway A and the corresponding output shaft raceway B, and the ball 51 forms two contact points with the inner wall raceway A and the output shaft raceway B respectively. There is a radial gap C between the inner wall raceway A and the corresponding output shaft raceway B. The ball 51 is sandwiched between the inner wall raceway A and the output shaft raceway B, and forms two contact points with the inner wall raceway A and the output shaft raceway B respectively, forming a four-point contact between the ball 51 and the annular raceway 7. Only corresponding raceways need to be provided on the middle matching section 42 and the inner wall of the housing 1. The ball 51 is assembled in place when it is installed between the inner wall raceway A and the output raceway B, thereby simplifying the assembly structure between the output shaft 4 and the housing 1, reducing assembly parts, and thus reducing the failure rate. The ball 51 is positioned by the inner wall raceway A and the corresponding output shaft raceway B, thereby ensuring the reliability of the axial positioning of the ball 51 between the output shaft 4 and the housing 1. The axial positioning, radial support and rotational connection of the output shaft 4 with the housing 1 are realized by the cooperation of the ball 51 and the annular raceway 7, thereby effectively simplifying the internal structure of the variable pitch reducer, and improving the load-bearing capacity and support stiffness.

[0031] The inner wall raceway A and the output shaft raceway B are formed by connecting two annular arc surfaces D with arc-shaped cross sections, and the two annular arc surfaces D respectively form point contacts with the ball 5. As shown in the figure, the inner wall raceway A and the output raceway B are in a flared shape arranged opposite to each other, and the two annular arc surfaces D are arranged opposite to each other and connected at the ends to form the inner wall raceway A and the output raceway B, and each annular arc surface D forms a contact point with the ball 51, so that the annular raceway 7 and the ball 51 form four contact points distributed in a rectangular shape, forming a four-point contact.

[0032] The multi-layer sealing assembly 6 at least includes an upper oil seal 61 disposed above the multi-row balls 5 and a lower oil seal 62 disposed below the multi-row balls 5. Since the multi-layer sealing assembly 6 is disposed below the final planet carrier 39, the upper oil seal 61 is located between the multi-row balls 5 and the final planet carrier 39, and the chamber where the multi-stage planetary reduction assembly 3 is located is sealed and separated from the chamber where the multi-row balls 5 are located. The lower oil seal 62 seals the chamber where the multi-row balls 5 are located, so that the multi-stage planetary reduction assembly 3 and the multi-row balls 5 can be lubricated separately. As shown in the figure, the multi-row balls 5 between the output shaft 4 and the housing 1 are two rows of balls. The upper oil seal 61 is disposed above the multi-row balls 5, and the lower oil seal 52 is disposed below, forming The independent sealed chamber of the multi-row balls 5 not only forms a seal for the chamber where the multi-row balls 5 are located, but also seals and separates the multi-row balls 5 from the multi-stage planetary reduction assembly 3, thereby preventing iron filings formed by the wear of the multi-stage planetary reduction assembly 3 from falling into the multi-row balls 5, and at the same time forms a multi-layer seal on the bottom of the box body. If the number of rows of the multi-row balls 5 is increased, the number of layers of the multi-layer sealing assembly 6 can be increased, and a sealing layer can be set in the multi-row balls 5 to divide the chamber where the multi-row balls 5 are located into multiple independent sealed chambers to ensure that each row of balls can be fully lubricated.

[0033] The inner cavity of the housing 1 is divided into an upper cavity E located above the upper oil seal 61 and a lower cavity F located between the upper oil seal 61 and the lower oil seal 62. The upper cavity E is filled with lubricating oil for lubricating the multi-stage planetary reduction assembly 3, and the lower cavity F is filled with grease for lubricating the multi-row ball bearings 5. The oil in the upper cavity E lubricates the multi-stage planetary reduction assembly 3, and the grease in the lower cavity F lubricates the multi-row ball bearings 5, so that the multi-stage planetary reduction assembly 3 and the multi-row ball bearings 5 ​​are lubricated separately. The grease can also prevent the leakage of the lubricating oil in the upper cavity E, improve the sealing efficiency, and ensure that the multi-stage planetary reduction assembly 3 and the multi-row ball bearings 5 ​​are fully lubricated respectively.

[0034] The housing 1 is composed of an upper housing 8 and a lower housing 9 coaxially fixed to the bottom of the upper housing 8. The multi-row balls 5 and the multi-layer sealing assembly 6 are respectively installed between the lower housing 9 and the output shaft 4. The inner cavity of the lower housing 9 includes a ring gear cavity 91 meshing with the final planetary gear 38, an assembly cavity 92 for assembling the multi-row balls 5 and the multi-layer sealing assembly 6, and a wedge-shaped transition cavity 93 arranged between the ring gear cavity 91 and the assembly cavity 92. The inner diameter of the assembly cavity 92 is smaller than that of the ring gear. The inner diameter of the cavity 91 and the wedge-shaped transition cavity 93 are wedge-shaped with a diameter gradually decreasing from top to bottom. An upper annular step surface 90 that cooperates with the upper oil seal 61 is arranged at the top of the assembly cavity 92, and a lower annular step surface 94 that cooperates with the lower oil seal 62 is arranged at the bottom of the assembly cavity 92. The upper oil seal 61 abuts against the upper annular step surface 90, and the lower oil seal 62 abuts against the lower annular step surface 94. An axial retaining ring 95 is installed in the assembly cavity 92 to support the lower oil seal 62. Multiple rows of balls 5 are installed in the assembly cavity 92, and the upper oil seal 61 is axially positioned by the upper annular step surface 90, and the lower oil seal 62 is axially positioned by the lower annular step surface 94 and the axial retaining ring 95, so that the multiple rows of balls 5 are sealed in the lower cavity F. The assembly of the multiple rows of balls 5 and the multi-layer sealing assembly 6 in the lower housing 9 is simple, and a sealed chamber for independently lubricating the multiple rows of balls is formed, which ensures the lubrication of the multiple rows of balls 5 while forming a multi-layer seal on the bottom of the housing 1 to prevent oil leakage.

[0035] The present invention also protects the design method of the wind turbine variable pitch reducer described above, which is characterized in that: the number of rows of multiple rows of balls 5, the ball diameter and the number of balls in each row are designed according to the radial load, axial load and torque transmission requirements of the output shaft 4. The number of rows of multiple rows of balls 5, the ball diameter and the number of balls in each row are set according to the load requirements of the output shaft 4, so as to improve the load capacity and support stiffness of the output shaft, adapt to the load requirements of harsh working conditions, ensure that the output shaft is set along the axial direction of the reducer without deviation, reduce the impact on the internal structure of the reducer, improve the stability of the variable pitch reducer, and prevent overturning.

[0036] The number of layers and the axial position of each layer of the multi-layer sealing assembly 6 are designed according to the number of rows of multi-row balls 5, the lubrication requirements and the sealing requirements of the housing 1. The multi-layer sealing assembly 6 forms a seal for the chamber where the multi-row balls 5 are located, and seals and separates the multi-row balls 5 from the multi-stage planetary reduction assembly 3, which can prevent iron filings formed by the wear of the multi-stage planetary reduction assembly 3 from falling into the multi-row balls 5, and at the same time forms a multi-layer seal on the bottom of the housing. According to the number of rows of multi-row balls 5, the number of layers of the multi-layer sealing assembly 6 can be increased, and a sealing layer is also set in the multi-row balls 5 to separate the chamber where the multi-row balls 5 are located into multiple independent sealed chambers to ensure that each row of balls can be fully lubricated.

[0037] The above is a complete description of the technical solutions of the embodiments of the present invention in conjunction with the accompanying drawings. It should be noted that the described embodiments are only part of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

Claims

1. A wind turbine variable pitch reducer, comprising a housing, an input shaft mounted in the housing, a multi-stage planetary reduction assembly mounted in the housing and meshing with the input shaft, and an output shaft meshing with the output end of the multi-stage planetary reduction assembly, wherein the output shaft extends from the housing, and is characterized in that: A plurality of rows of balls distributed axially from top to bottom are arranged between the output shaft and the housing, the plurality of rows of balls axially position the output shaft on the housing and form a rotational connection between the output shaft and the housing, and a multi-layer sealing assembly is assembled between the output shaft and the housing to separate the multi-stage planetary reduction assembly and the plurality of rows of balls and seal the bottom end of the housing.

2. The wind turbine variable pitch reducer according to claim 1, characterized in that: The multi-stage planetary reduction assembly includes a primary sun gear meshed with the input shaft, a primary planetary gear meshed with the primary sun gear, a primary planetary carrier connected to the primary planetary gear, a secondary sun gear meshed with the primary planetary carrier, a secondary planetary gear meshed with the secondary sun gear, a secondary planetary carrier connected to the secondary planetary gear, a final sun gear meshed with the secondary planetary carrier, a final planetary gear meshed with the final sun gear, and a final planetary carrier connected to the final planetary gear. The primary planetary gear, the secondary planetary gear and the final planetary gear are respectively meshed with the gear ring on the inner wall of the casing, the upper end of the output shaft is meshed with the final planetary carrier, and a multi-row ball bearing and a multi-layer sealing assembly are arranged below the final planetary carrier.

3. The wind turbine variable pitch reducer according to claim 2, characterized in that: The output shaft is integrally formed from top to bottom by an upper gear section meshing with the final planetary carrier, an intermediate matching section and a lower gear section extending out of the housing. Multiple rows of balls and a multi-layer sealing assembly are arranged between the inner wall of the housing and the intermediate matching section. An annular raceway is formed between the intermediate matching section and the inner wall of the housing. The annular raceway is evenly spaced along the axial direction. The multiple rows of balls are composed of balls installed in the annular raceway. The balls in the annular raceway are arranged in sequence to form a row of balls. Each ball forms four contact points with the annular raceway in a rectangular distribution.

4. The wind turbine variable pitch reducer according to claim 3, characterized in that: An inner wall raceway is provided on the inner wall of the box body, an output shaft raceway corresponding to the inner wall raceway is provided on the middle matching shaft, a radial gap is provided between the middle matching section and the inner wall of the box body so that the inner wall raceway and the corresponding output shaft raceway are separated and do not contact each other, the inner wall raceway and the corresponding output shaft raceway are radially aligned to form an annular raceway, the ball is sandwiched between the inner wall raceway and the corresponding output shaft raceway, and the ball forms two contact points with the inner wall raceway and the output shaft raceway respectively.

5. The wind turbine variable pitch reducer according to claim 4, characterized in that: The inner wall raceway and the output shaft raceway are both formed by connecting two annular arc surfaces with arc-shaped cross sections, and the two annular arc surfaces are in point contact with the balls respectively.

6. The wind turbine variable pitch reducer according to claim 2, characterized in that: The multi-layer sealing assembly at least comprises an upper oil seal arranged above the multiple rows of balls and a lower oil seal arranged below the multiple rows of balls.

7. The wind turbine variable pitch reducer according to claim 6, characterized in that: The inner cavity of the box body is divided into an upper cavity located above the upper oil seal and a lower cavity located between the upper oil seal and the lower oil seal. The upper cavity is filled with lubricating oil for lubricating the multi-stage planetary reduction assembly, and the lower cavity is filled with grease for lubricating the multi-row ball bearings.

8. The wind turbine variable pitch reducer according to claim 6, characterized in that: The housing is composed of an upper housing and a lower housing part coaxially fixed to the bottom of the upper housing, a plurality of rows of balls and a multi-layer sealing assembly are respectively installed between the lower housing and the output shaft, the inner cavity of the lower housing includes a gear ring cavity meshing with the final planetary gear, an assembly cavity for assembling the plurality of rows of balls and the multi-layer sealing assembly, and a wedge-shaped transition cavity arranged between the gear ring cavity and the assembly cavity, the inner diameter of the assembly cavity is smaller than the inner diameter of the gear ring cavity, the wedge-shaped transition cavity is wedge-shaped with a diameter gradually decreasing from top to bottom, an upper annular step surface matching with an upper oil seal is arranged at the top of the assembly cavity, a lower annular step surface matching with a lower oil seal is arranged at the bottom of the assembly cavity, the upper oil seal abuts against the upper annular step surface, the lower oil seal abuts against the lower annular step surface, and an axial retaining ring supporting the lower oil seal is arranged in the assembly cavity.

9. The design method of a wind turbine variable pitch reducer according to any one of claims 1 to 8, characterized in that: The number of rows of multi-row balls, the ball diameter and the number of balls in each row are designed according to the radial load, axial load and torque transmission requirements of the output shaft.

10. The design method of a wind turbine variable pitch reducer according to claim 9, characterized in that: The number of layers and the axial position of each layer of the multi-layer sealing assembly are designed according to the number of rows of multi-row balls, lubrication requirements and sealing requirements of the box.

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