Positioning structure for output shaft of gearbox

Abstract

The utility model relates to the technical field of wind driven generators, and discloses a positioning structure for an output shaft of a gearbox, which comprises a planet carrier and a bearing assembly, the bottom of the planet carrier is provided with a mounting hole for accommodating the end part of the output shaft, and the top of the planet carrier is provided with a fixing structure for connecting the output shaft with the planet carrier; the bearing assembly is arranged on the periphery of the planet carrier in a sleeving mode and comprises a bearing inner ring and a bearing outer ring, an inner raceway is formed in the bearing inner ring, an outer raceway is formed in the bearing outer ring, the inner raceway and the outer raceway are combined to form a first raceway and a second raceway, the second raceway is located below the first raceway, and the reference diameters of the first raceway and the second raceway are the same. An upper rolling ball and a lower rolling ball are installed in the first rolling way and the second rolling way respectively, the contact angle of the bearing assembly is not larger than 35 degrees, and the diameter of the lower rolling ball is larger than that of the upper rolling ball. According to the scheme, the compactness of the output positioning structure of the yaw gearbox is improved, the total height and weight are reduced, and the manufacturing cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of wind turbines, and particularly relates to a positioning structure for the output shaft of a gearbox. Background Art

[0002] As a speed reducer, the yaw gearbox is an important component of a wind turbine generator set. The yaw gearbox is vertically installed, and from top to bottom, it successively includes an input component, a planetary component (usually four stages), and an output component. The total height of the last-stage planetary component and the output component of the existing yaw gearbox is relatively large, the output positioning structure is not compact and has a relatively large weight, which increases the moment of inertia of the yaw system, increases the energy consumption during startup and stop, affects the overall efficiency of the wind power generation system. At the same time, under frequent yaw operations, the high energy consumption will directly affect the power generation cost and economic benefits of the wind turbine generator set.

[0003] Therefore, the applicant optimized and improved the above defects and applied for a Chinese invention patent, a yaw gearbox output pre-tightening positioning structure with the publication number of CN117090922A. This patent discloses that a bearing ball assembly is provided between the output housing and the planet carrier, and a roller bearing without an outer ring is provided between the planet carrier and the last-stage planet gear to improve the compactness of the output pre-tightening positioning structure. Although the above positioning structure has greatly improved the total height and weight of the yaw gearbox, the applicant found during subsequent further analysis and research that there is still room for further improvement in this structure. Therefore, the applicant further provides a positioning structure with a simple and compact structure. Summary of the Utility Model

[0004] The utility model aims to provide a positioning structure for the output shaft of a gearbox to improve the compactness of the output positioning structure of the yaw gearbox and reduce the overall height and weight of the yaw gearbox.

[0005] To achieve the above purpose, the utility model adopts the following technical scheme: A positioning structure for the output shaft of a gearbox includes a planet carrier and a bearing assembly. An installation hole for accommodating the end of the output shaft is opened at the bottom of the planet carrier, and a fixing structure for connecting the output shaft and the planet carrier is provided at the top of the planet carrier; the bearing assembly is sleeved on the outer periphery of the planet carrier. The bearing assembly includes an inner bearing ring and an outer bearing ring. An inner raceway is opened on the inner bearing ring, and an outer raceway is opened on the outer bearing ring. The inner raceway and the outer raceway are combined to form a first raceway and a second raceway. The second raceway is located below the first raceway, and the pitch circle diameters of the first raceway and the second raceway are the same. An upper rolling ball and a lower rolling ball are respectively installed in the first raceway and the second raceway. The contact angle of the bearing assembly is not greater than 35°, and the diameter of the lower rolling ball is larger than that of the upper rolling ball.

[0006] The principle and advantages of this scheme are:

[0007] 1. In this solution, the bottom of the planet carrier is provided with mounting holes for accommodating the end of the output gear shaft, and the top is provided with a fixing structure for connecting the output gear shaft. The outer periphery of the bottom of the planet carrier is sleeved with a bearing assembly. The bearing assembly includes an inner bearing ring and an outer bearing ring. The outer edge of the planet carrier overlaps on the inner bearing ring. Compared with the prior art, the connection between the planet carrier, the output gear shaft and the bearing assembly in this solution is tight and the structure is simple, effectively improving the structural compactness. At the same time, a connected first raceway and a second raceway are integrated between the inner bearing ring and the outer bearing ring, and upper balls and lower balls are concentrated in the same bearing to form a double-row ball bearing. The double-row ball bearing can provide a radial and axial load-bearing capacity equal to or even greater than that of a tapered roller bearing in a smaller space, effectively ensuring the bearing structural strength and anti-deformation ability. At the same time, the overall spatial span of the bearing structure is reduced, greatly reducing the overall volume of the positioning structure parts, improving the compactness of the output assembly, being beneficial to the lightweight and miniaturization design of the wind turbine, improving the space utilization rate and reducing the manufacturing cost.

[0008] 2. In this solution, the contact angle between the balls and the raceways is within 35°. Therefore, under the condition of the same load, compared with the structure of using multiple bearings to cooperate in bearing force in the traditional way, this bearing structure is more compact and miniaturized. Secondly, the smaller contact angle enables the upper and lower balls to share the load applied to the bearing more evenly, thus reducing the probability that a single ball bears too large a load. Therefore, the upper ball generally does not reach its maximum load-bearing potential. Furthermore, in this solution, the upper and lower balls are designed with different diameters, one small and one large. Such a design not only effectively ensures that the upper ball can exert its maximum load-bearing potential and improves the economy, but also further reduces the height of the bearing assembly by reducing the diameter of the upper ball, improving the structural compactness.

[0009] 3. In this solution, the pitch circle diameters of the first raceway and the second raceway are the same, which helps to distribute the load between the upper and lower balls more evenly, and can maintain a better force balance even under dynamic working conditions, avoiding excessive force on a single rolling element, thereby extending the bearing service life. At the same time, the same pitch circle diameter ensures that the upper ball and the lower ball can maintain the same radial movement trajectory during rotation, ensuring the high-precision operation of the yaw gearbox, and the improvement of the coaxiality reduces the vibration and noise during operation, improving the operation stability of the entire wind power generation system.

[0010] 4. Compared with the existing yaw output assembly design with multiple independent bearings, the double-row ball bearing design of this scheme not only significantly reduces the number of bearings, but also makes the bearing structure more centralized, making the bearing lubrication system more centralized and efficient. While reducing the number of lubrication points, it also reduces the complexity of the cooling system, helps to maintain a good operating temperature, and extends the service life of the bearings and gearbox. Moreover, the reduction in the number of bearings effectively simplifies the internal structure of the yaw gearbox, reduces the design complexity and assembly difficulty, improves production efficiency, and also facilitates subsequent maintenance and overhaul work.

[0011] Furthermore, the diameter ratio of the upper rolling ball to the lower rolling ball is 0.7-0.9.

[0012] Within the above-mentioned diameter ratio range, the upper and lower balls are subjected to uniform force. When the diameter ratio of the two balls is smaller than the above-mentioned range, the diameter of the upper ball located on top is too small to meet its own force requirements. When the diameter ratio of the two balls is larger than the above-mentioned range, the lower ball originally carries more load, and after the diameter of the upper ball increases, it will try to participate in load sharing more equally. However, due to physical limitations, the increase in the carrying capacity of the upper ball is not completely linear, so it cannot significantly reduce the burden on the lower layer. In fact, in the case of improper adjustment, the uneven load distribution will increase the force on the large-diameter ball in the lower layer, increase the fatigue damage of the lower ball, and reduce its service life.

[0013] Furthermore, the first raceway and the second raceway are both raceways with peach-shaped cross sections. The peach-shaped design of the raceway cross section makes the force distribution of the bearing assembly more uniform.

[0014] Furthermore, the fixing structure includes a fixing bolt for connecting the planet carrier and the output shaft and a gasket located between the fixing bolt and the planet carrier, the end of the fixing bolt extends into the output gear shaft, a gasket groove is opened on the upper part of the planet carrier, and the gasket is fixed in the gasket groove.

[0015] The planetary carrier and the output gear shaft are fastened together by the fixing bolts. During the connection process, the fixing bolts can pre-tighten the bearing assembly to increase the stiffness of the bearing assembly. At the same time, the output gear shaft and the positioning structure can be accurately positioned axially and radially to increase the rotation accuracy of the output shaft. In addition, the gasket is provided to reduce the friction damage between the fixing bolts and the planetary carrier and to enable the clamping force of the fixing bolts to be more evenly applied to the planetary carrier.

[0016] Furthermore, a shoulder is provided between the first raceway and the second raceway, and the height of the shoulder is 3-6 mm.

[0017] The shoulder is set to provide guidance and limitation for the upper and lower balls. In dynamic load and vibration environment, the shoulder can effectively constrain the movement trajectory of the balls, reduce unnecessary degrees of freedom of movement, and improve the overall working reliability of the bearing.

[0018] The height of the shoulder is designed to be 3 - 6 mm. Firstly, if the height of the shoulder is too high, the center distance between the upper rolling ball and the lower rolling ball will increase. Since the first and second raceways are no longer adjacent, the radial reaction forces transmitted from the upper rolling ball to the inner and outer rings of the bearing will cause slight elastic deformation of the inner and outer rings of the bearing. This deformation will cause the contact pressure at the lower rolling ball to increase because more force is required to balance the external load and the internal preload, resulting in an increase in the force borne by the lower rolling ball compared to when the center distance is smaller. Secondly, if the height of the shoulder is too high, the overall height of the bearing will increase, which is contradictory to the purpose of a compact structure.

[0019] Furthermore, oil seals are provided between the upper and lower ends of the outer ring of the bearing and the inner ring of the bearing and the planetary carrier respectively.

[0020] The oil seals on the upper and lower sides form a sealed lubrication space between the inner and outer rings of the bearing, effectively preventing dust and impurities from entering the bearing interior, reducing the friction and wear between the rolling balls and the raceways, and extending the service life of the bearing.

[0021] Furthermore, the upper end of the outer ring of the bearing protrudes radially to form a mounting platform. An installation groove is opened on the inner side of the mounting platform, and the bottom of the installation groove is flush with the upper end face of the inner ring of the bearing. The oil seal located above is arranged in the installation groove; the lower part of the planetary carrier is stepped, and its shoulder is located in the installation groove and is mounted on the inner ring of the bearing.

[0022] The outer ring of the bearing with the mounting platform serves as the output housing, reducing the overall number of components of the output structure, making the structure more compact. It also simplifies the installation process of the bearing in the yaw gearbox, provides a stable installation interface, ensures the correct and reliable positioning of the bearing and the output shaft, avoids initial faults caused by improper installation, and improves the assembly efficiency. Secondly, the shoulder of the planetary carrier being located in the installation groove and mounted on the inner ring of the bearing is beneficial for installation positioning and simplifies the installation process. At the same time, the shoulder of the planetary carrier presses and fixes the oil seal in the installation groove, eliminating the need for an additional structure to fix the oil seal, making the positioning between the bearing and the planetary carrier more accurate and improving the structural accuracy of the output assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic assembly diagram of the positioning structure and the output gear shaft according to an embodiment of the present invention.

[0024] Figure 2 It is a schematic structural diagram of the bearing assembly according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The following is a more detailed description through specific embodiments:

[0026] The reference numerals in the attached drawings of the description include: output gear shaft 100, sun gear 200, planet carrier 1, mounting hole 11, fixing structure 2, fixing bolt 21, gasket 22, bearing assembly 3, bearing inner ring 31, bearing outer ring 32, first raceway 33, second raceway 34, upper rolling ball 35, lower rolling ball 36, shoulder 37, mounting table 38, mounting groove 39, oil seal 4.

[0027] Embodiment

[0028] Basically as shown in the attached Figure 1 - Figure 2 drawings: A positioning structure for the output shaft of a gearbox, comprising a planet carrier 1 and a bearing assembly 3. The bearing assembly 3 is sleeved on the outer periphery of the planet carrier 1 and is connected by interference fit or spline fit to prevent slippage between the two; an installation hole 11 for accommodating the end of the output gear shaft 100 is opened at the bottom of the planet carrier 1. The output gear shaft 100 is in interference fit or connected by spline fit with the installation hole 11 of the planet carrier 1 to achieve transmission between the two. A fixing structure 2 for connecting the output gear shaft 100 and the planet carrier 1 is provided at the top of the planet carrier 1. The fixing structure 2 includes a fixing bolt 21 and a gasket 22. The fixing bolt 21 is used to connect the planet carrier 1 and the output gear shaft 100. The head of the fixing bolt 21 is located inside the sun gear 200. The end of the fixing bolt 21 extends into the output gear shaft 100 and the length of the shank of the fixing bolt 21 located inside the output gear shaft 100 is not less than 1 / 2 of the depth of the installation hole 11, so as to ensure the stable connection between the planet carrier 1 and the output gear shaft 100; a gasket groove is opened at the upper part of the planet carrier 1. The gasket 22 is fixed in the gasket groove to separate the planet carrier 1 from the fixing bolt 21, so as to reduce the direct friction loss between the two and ensure that the pressing force of the fixing bolt 21 can be evenly applied to the planet carrier 1.

[0029] The bearing assembly 3 includes a bearing inner ring 31 and a bearing outer ring 32. The lower end surface of the bearing inner ring 31 is lower than the lower end surface of the planet carrier 1 and fits with the middle step surface of the output gear shaft 100. There is a gap between the upper end surface of the output gear shaft 100 and the gasket 22. During the connection process, the fixing bolt 21 can pre-tighten the bearing assembly 3 to improve the stiffness of the bearing assembly 3. At the same time, it can also accurately position the output gear shaft 100 axially and radially with the positioning structure, and improve the rotation accuracy of the output gear shaft 100.

[0030] An inner raceway is formed on the inner ring 31 of the bearing, and an outer raceway is formed on the outer ring 32 of the bearing. The inner raceway and the outer raceway are combined to form a first raceway 33 and a second raceway 34. The second raceway 34 is located below the first raceway 33, and the pitch circle diameters of the first raceway 33 and the second raceway 34 are the same. Both the first raceway 33 and the second raceway 34 are raceways with a peach-shaped cross-section, so that the bearing assembly 3 is more evenly stressed; upper rolling balls 35 and lower rolling balls 36 are respectively installed in the first raceway 33 and the second raceway 34. The contact angle of the bearing assembly 3 is 20°-35°. Thus, under the condition of bearing the same load, compared with the structure of using multiple bearings to cooperate in bearing force in the traditional way, the bearing structure of the present invention is more compact and smaller. Preferably, in this embodiment, the contact angle is 30°. At this contact angle, the centrifugal force of the rolling balls can be more effectively controlled, ensuring the lasting stability and safe operation of the bearing assembly 3 at high speeds. At the same time, when bearing dynamic loads, the 30° contact angle can provide better rolling guidance and control, reduce non-linear vibration, improve the dynamic response performance of the entire system, and at the same time reduce wear and energy consumption.

[0031] Preferably, the diameter of the lower rolling balls 36 is larger than that of the upper rolling balls 35, and the diameter ratio of the upper rolling balls 35 to the lower rolling balls 36 is 0.7-0.9. Within the above diameter ratio range, both the upper rolling balls 35 and the lower rolling balls 36 are evenly stressed. When the diameter ratio of the two rolling balls is less than the above range, that is, the diameter of the upper rolling balls 35 located above is too small to meet the requirements of its own force bearing; when the diameter ratio of the two rolling balls is greater than the above range, originally the lower rolling balls 36 bear more loads. After the diameter of the upper rolling balls 35 increases, it will try to participate in load sharing more equally. However, due to physical limitations, the increase in the load-bearing capacity of the upper rolling balls 35 is not completely linear, so it cannot significantly reduce the burden on the lower layer. Even in the case of improper adjustment, due to uneven load distribution, the force on the large-diameter rolling balls in the lower layer increases, and the fatigue damage of the lower rolling balls 36 increases, and the service life is reduced.

[0032] A shoulder 37 is provided between the first raceway 33 and the second raceway 34 to provide guidance and limit for the upper rolling balls 35 and the lower rolling balls 36, and effectively restrict the movement trajectory of the rolling balls, reduce unnecessary degrees of freedom of movement, and improve the overall working reliability of the bearing. Preferably, the height of the shoulder 37 is designed to be 3-6 mm. In this embodiment, the height of the shoulder 37 is 5 mm. First, if the shoulder 37 is too high, the center distance between the upper rolling balls 35 and the lower rolling balls 36 will increase. Since the first raceway 33 and the second raceway 34 are no longer adjacent, the radial reaction forces transmitted by the upper rolling balls to the inner ring 31 and the outer ring 32 of the bearing will cause slight elastic deformation of the inner ring 31 and the outer ring 32 of the bearing. This deformation will cause the contact pressure at the lower rolling balls 36 to increase because more force is required to balance the external load and the internal preload, so that the force borne by the lower rolling balls 36 increases compared with when the center distance is smaller; second, if the height of the shoulder 37 is too high, the overall height of the bearing will increase, which is contradictory to the purpose of a compact structure.

[0033] Sealing rings 4 are provided between the upper and lower ends of the outer bearing ring 32 and the inner bearing ring 31 and the planet carrier 1 respectively. The sealing rings 4 on the upper and lower sides form a sealed lubricating space between the inner bearing ring 31 and the outer bearing ring 32, effectively preventing dust and impurities from entering the bearing interior, reducing the friction and wear between the balls and the raceways, and prolonging the service life of the bearing. The upper end of the outer bearing ring 32 protrudes radially to form a mounting platform 38. An installation groove 39 is formed on the inner side of the mounting platform 38. The bottom of the installation groove 39 is flush with the upper end face of the inner bearing ring 31. The lower part of the planet carrier 1 is stepped and its shoulder is mounted on the inner bearing ring 31. The upper sealing ring 4 is arranged in the installation groove 39 and is located between the outer bearing ring 32 and the planet carrier 1. In this way, not only is it convenient for the planet carrier 1 to be quickly positioned and assembled, but also the upper sealing ring 4 is fixed by using the existing structure without the need to additionally set up a structure to fix the sealing ring 4, which not only simplifies the overall structure and the installation process, but also makes the positioning between the bearing and the planet carrier 1 more accurate, improving the structural accuracy of the output assembly.

[0034] The above are only the embodiments of the present invention. Well-known specific technical solutions and / or common knowledge such as characteristics are not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several modifications and improvements can be made, which should also be regarded as the protection scope of the present invention and will not affect the implementation effect of the present invention and the practicality of the patent. The protection scope required by this application shall be subject to the content of its claims, and the specific implementation manners described in the specification can be used to interpret the content of the claims.

Claims

1. A positioning structure for the output shaft of a gearbox, characterized in that: It includes a planet carrier and a bearing assembly. An installation hole for accommodating the end of the output shaft is formed at the bottom of the planet carrier, and a fixing structure for connecting the output shaft and the planet carrier is provided at the top of the planet carrier; the bearing assembly is sleeved on the outer periphery of the planet carrier. The bearing assembly includes an inner bearing ring and an outer bearing ring. An inner raceway is formed on the inner bearing ring, and an outer raceway is formed on the outer bearing ring. The inner raceway and the outer raceway are combined to form a first raceway and a second raceway. The second raceway is located below the first raceway, and the pitch circle diameters of the first raceway and the second raceway are the same. An upper ball and a lower ball are respectively installed in the first raceway and the second raceway. The contact angle of the bearing assembly is not greater than 35°, and the diameter of the lower ball is larger than that of the upper ball.

2. The positioning structure for the output shaft of a gearbox according to claim 1, wherein: The diameter ratio of the upper ball to the lower ball is 0.7 - 0.

9.

3. The positioning structure for the output shaft of the gearbox according to claim 2, characterized in that: Both the first raceway and the second raceway are raceways with a peach-shaped cross-section.

4. A positioning structure for the output shaft of a gearbox according to claim 3, characterized in that: The fixing structure includes a fixing bolt for connecting the planet carrier and the output shaft and a gasket located between the fixing bolt and the planet carrier. The end of the fixing bolt extends into the output gear shaft, and a gasket groove is formed in the upper part of the planet carrier. The gasket is fixed in the gasket groove.

5. A positioning structure for the output shaft of a gearbox according to claim 4, characterized in that: A shoulder is provided between the first raceway and the second raceway, and the height of the shoulder is 3 - 6 mm.

6. The positioning structure for the output shaft of a gearbox according to claim 5, characterized in that: Oil seals are respectively provided between the upper and lower ends of the outer bearing ring and the inner bearing ring and the planet carrier.

7. A positioning structure for the output shaft of a gearbox according to claim 6, characterized in that: An installation platform protrudes radially from the upper end of the outer bearing ring. An installation groove is formed on the inner side of the installation platform, and the bottom of the installation groove is flush with the upper end face of the inner bearing ring. The oil seal located above is arranged in the installation groove; the lower part of the planet carrier is stepped, and its shoulder is located in the installation groove and is installed on the inner bearing ring.

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