A high-strength high-rigidity planetary carrier

Abstract

The application discloses a high-strength and high-rigidity planet carrier and relates to the field of planet carrier structures.The planet carrier comprises a front side plate, a rear side plate and a plurality of support columns, the arrangement directions of the front side plate and the rear side plate are in the axial direction, the support columns are assembled between the front side plate and the rear side plate and are located at the outer edges of the front side plate and the rear side plate, the front side plate and the rear side plate are matched to form a cavity for accommodating gears, the support columns protrude outward from the cavity, have a first arc-shaped surface located at the inner side and protruding outward and a second arc-shaped surface located at the outer side and protruding outward, the first arc-shaped surface and the second arc-shaped surface are smoothly connected with the front side plate and the rear side plate, and the two sides of the support column have concave arc-shaped edges which are smoothly connected with the inner surfaces of the front side plate and the rear side plate in the circumferential direction of the cavity.The planet carrier is designed in the structural mode, interference between the planet carrier and the planet wheel is effectively avoided, stress caused by alternating loads is effectively dispersed, the strength and the rigidity are improved and the purposes are achieved.

Description

Technical Field

[0001] This invention relates to the field of planetary carrier structures, and in particular to a high-strength, high-rigidity planetary carrier. Background Technology

[0002] In the field of mechanical transmission, planetary gear drives are widely used in equipment such as gearboxes of wind turbine generators and rotary reducers of aircraft turbines due to their advantages such as high transmission efficiency, large transmission ratio, and compact structure. As the core component of the planetary gear transmission system, the planet carrier's main function is to support the planetary gears and transmit torque. Its structural strength, rigidity, and stability directly affect the operational reliability, service life, and transmission efficiency of the entire transmission system.

[0003] In the gearbox of a wind turbine generator, the planetary carrier is generally composed of a front side plate, a rear side plate, and a support column connecting the two. The support column is arranged circumferentially along the outer edge of the front and rear side plates (hereinafter collectively referred to as side plates) to form a cavity for accommodating the gears (multiple planetary gears and a sun gear). The sun gear is located at the center of this cavity, and multiple planetary gears are located in the cavity and arranged circumferentially around the sun gear. During operation, the connection between the support column and the side plate is a critical area of ​​stress concentration. It is very easy for the connection between the support column and the side plate to crack due to alternating loads (the torque of the sun gear when it rotates in both directions) or for the support column to crack, leading to the failure of the planetary carrier.

[0004] Alternating loads causing planetary carrier failure is a common problem in the industry. To solve this problem, engineers have done a lot of design work. For example, in traditional designs, to reduce the risk of cracking, rounded corners are used at the connection between the support column and the side plate. However, while an excessively large rounded corner increases the material at the connection between the support column and the side plate, thus increasing strength, it also presents the technical problem of "interference between the planetary gears and the planetary carrier due to the increased material." Therefore, when using rounded corners at the connection between the support column and the side plate, the rounded corner cannot be too large; on the other hand, a rounded corner that is too small cannot effectively disperse the stress brought by alternating loads. In other words, there is a contradiction between stress dispersion and assembly space. At the same time, in traditional designs, to ensure smooth assembly of the planetary gears, sufficient space is usually reserved between adjacent support columns, often achieved by reducing the length of the support column (the circumferential dimension of the planetary carrier). This reduces the overall stiffness of the planetary carrier, exacerbates gearbox vibration, and affects the stability and service life of the transmission system. Of course, there are other designs for planetary carriers in the industry. For example, Chinese patent CN210661310U discloses a planetary carrier for wind turbine gearboxes. To solve the problem of "connecting plate (equivalent to connecting column) breakage", it adopts a technical solution of tilt angle setting + transition fillet. The initial tilt angle of the connecting plate reserves "buffer space" for torsional deformation during operation and passively adapts to deformation. Chinese patent CN115427710A discloses a planetary carrier planetary transmission device transmission system and wind turbine. To solve the problem of "lightweight structure", it adopts a reciprocal curved surface technical solution. By setting convex and concave bends on one surface at the same time, stress concentration caused by small radius is avoided. Chinese patent CN103511604A discloses a planetary carrier for a planetary gear transmission mechanism. To solve the problem of "weight and strength optimization", it adopts a ball seat-shaped transition area technical solution. By removing material from the connecting area through the ball seat (concave contour), the wall thickness is reduced while adapting to the force flow line. None of these three technical solutions can effectively resolve the contradiction between stress dispersion and assembly space. Therefore, further research is needed in the industry to address this issue. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems by providing a high-strength and high-rigidity planetary carrier. Through structural design, it effectively avoids interference between the planetary carrier and the planetary gears while effectively dispersing the stress caused by alternating loads, thereby improving strength and rigidity.

[0006] The technical solution adopted in this invention is as follows: A high-strength and high-rigidity planetary carrier includes a front side plate, a rear side plate, and multiple support columns. The front side plate and the rear side plate are arranged in the axial direction. The support columns are assembled between the front side plate and the rear side plate and are located at the outer edges of the front side plate and the rear side plate, forming a cavity for accommodating gears. The support columns protrude outward from the cavity and have a first arc-shaped surface located on the inner side and protruding outward and a second arc-shaped surface located on the outer side and protruding outward. Both the first arc-shaped surface and the second arc-shaped surface smoothly transition with the front side plate and the rear side plate. In the circumferential direction of the cavity, the two sides of the support columns have concave arc-shaped edges that smoothly transition with the inner surfaces of the front side plate and the rear side plate.

[0007] Furthermore, in the circumferential direction of the cavity and on the first arc-shaped surface, the distance from the point where the arc-shaped edge smoothly transitions with the inner surfaces of the front and rear side plates to the deepest point of the arc-shaped edge is 'a', where the dimension of 'a' is 1 / 8 to 1 / 4 of the circumferential length of the first arc-shaped surface; in the axial direction of the cavity, the maximum width of the arc-shaped edge is 'b'; therefore, a / b ≥ 1 / 2.

[0008] Furthermore, the first arc-shaped surface is C-shaped or U-shaped; and / or the second arc-shaped surface is C-shaped or U-shaped; and / or the arc-shaped edge is C-shaped or U-shaped.

[0009] Furthermore, the plurality of the support columns are arranged in a circumferential array along the cavity.

[0010] Furthermore, the first arcuate surface has a smaller circumferential dimension than the second arcuate surface, so that the two sides of the support column have inclined surfaces in the circumferential direction of the cavity. The inclined surfaces are arcuate surfaces that match the curvature of the arcuate edges, and the inclined surfaces smoothly transition with the inner surfaces of the front and rear side plates.

[0011] Furthermore, the smooth transition can be either a rounded corner smooth transition or a tangent smooth transition.

[0012] Furthermore, the outer surfaces of the front and rear side plates have arc-shaped notches at the connection points with the support columns, and these arc-shaped notches are located between the two arc-shaped edges of the support column.

[0013] Furthermore, the arc-shaped notch is located at the connection point between the support column and the front side plate, and between the support column and the rear side plate, and allows for material removal from the front side plate, the support column, and the rear side plate.

[0014] Furthermore, after setting the arc-shaped notch, the dimension c of the residual material on the first arc-shaped surface in the axial direction of the cavity is 1 / 4 to 3 / 4 of the dimension of the support column in that direction.

[0015] Furthermore, the edges between adjacent faces on the planetary mount have rounded corners.

[0016] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: This invention, by incorporating a first and a second arc-shaped surface, effectively disperses the stress caused by alternating loads, significantly reducing the risk of cracking at the connection points between the support column and the front and rear side plates, and substantially improving the overall strength of the planetary carrier. Simultaneously, the arc-shaped edge design avoids interference with the planetary gears during assembly. Furthermore, the presence of these arc-shaped edges ensures sufficient circumferential connection length between the support column and the front and rear side plates, allowing the stress on the connecting column to be more dispersed across the front and rear side plates, effectively improving the connection strength between the front and rear side plates and the connecting column. In summary, the planetary carrier disclosed in this invention effectively resolves the contradiction between stress dispersion and assembly space, achieving both effective avoidance of interference between the planetary carrier and the planetary gears and effective dispersion of stress caused by alternating loads. Attached Figure Description

[0017] The present invention will be described by way of example and with reference to the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a front view structural diagram of the present invention; Figure 3 for Figure 2 Schematic diagram of the cross-sectional structure in the middle EE direction; Figure 4 The topology calculation of the force flow path for the planetary carrier is shown in Figure 1. Figure 5 The topology calculation of the force flow path for the planetary carrier is shown in Figure 2. Figure 6 The actual working condition verification of the planetary carrier is shown in Figure 1. Figure 7 The second part demonstrates the actual working condition verification of the planetary carrier. The markings in the diagram are: 1-front side plate; 2-rear side plate; 3-connecting column; 31-arc edge; 32-first arc surface; 33-second arc surface; 34-inclined surface; 5-cavity. Detailed Implementation

[0018] In the description of this specification, it should be noted that if terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," or "outer" appear to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, they are only for the convenience of describing this specification and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this specification.

[0019] Furthermore, the use of terms such as "horizontal" and "vertical" in this specification does not imply that the component must be absolutely horizontal or suspended, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0020] In the description of this specification, it should also be noted that, unless otherwise expressly specified and limited, the terms “set up,” “install,” “connect,” and “link” should be interpreted broadly. For example, a link can be a fixed link, a detachable link, or an integral link; it can be a mechanical link or an electrical link; it can be a direct link or an indirect link through an intermediate medium; it can be a connection within two components.

[0021] Example 1 like Figures 1-3 As shown, a high-strength and high-rigidity planetary carrier includes a front side plate 1, a rear side plate 2, and multiple support columns. The front side plate 1 and the rear side plate 2 are arranged axially. The support columns are assembled between the front side plate 1 and the rear side plate 2 and are located at the outer edges of the front side plate 1 and the rear side plate 2, forming a cavity 5 for accommodating gears. The support columns protrude outward from the cavity 5 and have a first arc-shaped surface 32 located on the inner side and protruding outward and a second arc-shaped surface 33 located on the outer side. Both the first arc-shaped surface 32 and the second arc-shaped surface 33 smoothly transition with the front side plate 1 and the rear side plate 2. In the circumferential direction of the cavity 5, the two sides of the support columns have concave arc-shaped edges 31 that smoothly transition with the inner surfaces of the front side plate 1 and the rear side plate 2.

[0022] In this embodiment, for ease of explanation, the axial direction of the cavity 5 is defined as the axial direction, the radial direction of the cavity 5 as the radial direction, and the circumferential direction of the cavity 5 as the circumferential direction; in the axial direction, the dimension of the support column is the width dimension; in the circumferential direction, the dimension of the support column is the length dimension; in the radial direction, the dimension of the support column is the thickness dimension; with the edges of the front side plate 1 and the rear side plate 2 as the boundary, the area inside the cavity 5 is called the inner side, and the area outside the cavity 5 is called the outer side.

[0023] Therefore, in this embodiment, the first arc-shaped surface 32 and the second arc-shaped surface 33 are convex, similar to an arch, which can effectively disperse the counter-torque load applied to the planetary carrier when the planetary gear is working, thus making the planetary carrier more effective in bearing stress. At the same time, by using the first arc-shaped surface 32 and the second arc-shaped surface 33 to connect with the front side plate 1 and the rear side plate 2 through a smooth transition, the stress can be diffused from the support column to the front side plate 1 and the rear side plate 2 under the "streamlined force flow guidance", effectively avoiding the stress concentration at the connection between the support column and the front side plate 1 and the rear side plate 2, reducing the stress peak, and thus reducing the risk of planetary carrier cracking. Based on this design, although it can effectively solve the problem caused by stress concentration, the outward convexity of the first arc surface 32 and the second arc surface 33, due to the planet carrier being a circular structure, naturally increases the circumferential dimension (length) of the connecting column 3, thereby compressing the space between adjacent connecting columns 3. In other words, this measure does not actually effectively solve the problem of interference between the planetary gear and the planet carrier. Therefore, in this embodiment, an arc edge 31 is also provided. The presence of this arc edge 31 not only provides space for the planetary gear but also enables an increase in strength. Specifically: In this embodiment, because the arc-shaped edge 31 does not exist in a direction perpendicular to the front side plate 1 and the rear side plate 2 (although the support column is parallel to the axial direction in the width direction), it is possible to make a larger diameter arc transition between the two sides of the support column and the front side plate 1 and the rear side plate 2 (see...). Figure 1 , Figure 3 (as indicated by "A"), thus more material is present at this connection point, increasing strength; at the same time, the setting of the arc edge 31 does not affect the connection length between the support column and the front side plate 1 and the rear side plate 2 (see...). Figure 1 , Figure 2 The dimension “l” in the middle is used to maintain the connection strength between the support column and the front side plate 1 and the rear side plate 2.

[0024] Force flow path topology calculations were performed on the planetary carrier to maximize structural stiffness, using cavity 5 as a non-designable region as a forced constraint for iterative calculations; the calculation results show that... Figures 4-5 As shown, the specific design of this planetary carrier is also the result of automatic convergence of the stress-coherence algorithm (the area with material is the area of ​​dense force flow distribution), which fully proves that the planetary carrier disclosed in this embodiment effectively solves the contradiction between stress dispersion and assembly space, that is, it effectively avoids interference between the planetary carrier and the planetary gears, while achieving the purpose of effectively dispersing the stress brought by alternating loads.

[0025] Example 2 Based on Example 1, further feasible implementation methods are proposed.

[0026] As described in Example 1, the design of this planetary carrier also conforms to the theoretical configuration of force flow path topology calculation; however, in actual production, planetary carriers are all produced using the same casting draft method, therefore, further design is required in the specific structure; specifically, one optional implementation method is as follows: Figure 1 , Figure 2 As shown, in the circumferential direction of the cavity 5 and on the first arc-shaped surface 32, the distance from the point where the arc-shaped edge 31 smoothly transitions with the inner surface of the front side plate 1 and the rear side plate 2 to the deepest point of the arc-shaped edge 31 is 'a'. The dimension of 'a' is 1 / 8 to 1 / 4 of the circumferential length of the first arc-shaped surface 32; in the axial direction of the cavity 5, the maximum width of the arc-shaped edge 31 is 'b'; therefore, a / b ≥ 1 / 2. This design ensures that the stiffness required for stress dispersion is fully utilized and that the planetary carrier can be smoothly demolded during the casting process, realizing the transformation from the theoretical configuration to a practically producible configuration. Specifically: Constraining the dimensions of a preserves the existence of the curved edge 31, thus preserving the technical effect brought by the curved edge 31; at the same time, it also preserves the material in the middle of the connecting column 3, thus preserving the stiffness required for the connecting column 3 to withstand stress flow on the planetary carrier; constraining a / b≥1 / 2 ensures smooth demolding of the planetary carrier.

[0027] In one feasible implementation, the first arc-shaped surface 32 is C-shaped or U-shaped; and / or the second arc-shaped surface 33 is C-shaped or U-shaped; and / or the arc-shaped edge 31 is C-shaped or U-shaped. The C-shaped or U-shaped surfaces can use the same radius of curvature, or different radii of curvature can be used according to actual needs. When the same radius of curvature is used, uniform stress dispersion at the connection between the support column and the front side plate 1 and the rear side plate 2 can be achieved through a stable curved surface shape, simplifying the processing technology and ensuring the consistency of stress in the transition area. When different radii of curvature are used, differentiated designs can be made for the stress distribution characteristics of different connection parts on the support column and the front side plate 1 and the rear side plate 2. For example, a larger radius of curvature can be used at the inner side connection where stress concentration is more obvious to enhance the dispersion effect, and a smaller radius of curvature can be used at the outer side connection to adapt to the outer circumferential surface shape. This ensures the strength of each part while more accurately adapting to the planetary gear assembly space and avoiding interference. The C-shaped arc achieves gradual stress dispersion through continuous curvature radius, which allows for smoother force flow at the connection between the support column and the side plate, avoiding abrupt changes; the U-shaped structure, on the other hand, uses a combination of arc buffering and straight line directional guidance to precisely control the stress transmission path, using arcs to alleviate concentration and straight lines to adapt to specific space or stress requirements.

[0028] In one feasible implementation, the multiple support columns are arranged in a circumferential array along the cavity 5; the regularity of the circumferential array simplifies the design modeling, facilitates the use of mold casting, CNC machining and other processes, and reduces manufacturing difficulty and cost; during assembly, the symmetrical layout provides a clear reference for part alignment, improving assembly efficiency and accuracy; in terms of stress dispersion, it also makes the stress flow more uniformly distributed relative to the front side plate 1 and the rear side plate 2.

[0029] One feasible implementation method is, for example Figure 3 As shown, the first arc-shaped surface 32 has a smaller circumferential dimension than the second arc-shaped surface 33. This design results in inclined surfaces 34 on both sides of the support column in the circumferential direction. These inclined surfaces 34 are arc-shaped surfaces that match the curvature of the arc-shaped edge 31. The inclined surfaces 34 further allow space for the planetary gears, preventing interference. At the same time, the feature that "the inclined surfaces 34 are arc-shaped surfaces that match the curvature of the arc-shaped edge 31" enables a smooth transition between the inclined surfaces 34 and the front and rear side plates 1 and 2. This allows for a smooth transition with a larger diameter arc, increasing the material at the connection point and achieving connection strength. Simultaneously, the smooth transition also allows stress flow to diffuse smoothly to the front and rear side plates 1 and 2, avoiding stress concentration.

[0030] In one feasible implementation, the smooth transition can be either a rounded corner smooth transition or a tangential smooth transition. By using a rounded corner smooth transition or a tangential smooth transition, the slight sharp corners that may exist at the joint between the two can be eliminated, avoiding the formation of new stress concentration points. This allows for a more coherent transmission of force from the connecting column 3 to the front side plate 1 and the rear side plate 2, which can enhance local fatigue resistance, especially under high load conditions.

[0031] Example 3 Based on Examples 1-2, further feasible implementation methods are proposed.

[0032] like Figure 3 As shown, after performing force flow path topology calculations on the planetary carrier disclosed in Embodiment 1, it was found that the amount of material is relatively small at the connection points between the support column and the front side plate 1 and the rear side plate 2, and between the two arc-shaped edges 31 on the same support column. Therefore, the stress flow distribution at this location is relatively small. To address this, a feasible implementation involves an arc-shaped notch at the connection points between the outer surfaces of the front side plate 1 and the rear side plate 2 and the support column. This arc-shaped notch is located between the two arc-shaped edges 31 on the support column. The design of this arc-shaped notch does not affect the effect of dispersing stress flow on the planetary carrier, and at the same time, by removing material, it effectively reduces the weight of the planetary carrier. Furthermore, in actual operation, the presence of the arc-shaped notch reduces material accumulation in areas far from the center of rotation, effectively reducing the rotational inertia of the planetary carrier, making it easier for the planetary carrier to respond during startup, speed change, or braking, reducing drive energy consumption, and improving the dynamic performance of the transmission system.

[0033] It should be noted that the arc-shaped notch still has an arc transition, avoiding stress concentration caused by right angles or sharp corners.

[0034] Furthermore, the arc-shaped notch is located at the connection point between the support column and the front side plate 1, the support column and the rear side plate 2, which allows for material removal from the front side plate 1, the support column and the rear side plate 2.

[0035] Based on practical application and production, further design of the arc-shaped notch is required, as detailed below: After setting the arc-shaped notch, as follows Figure 1 , Figure 2 As shown, the dimension c of the residual material on the first arc surface 32 in the axial direction of the cavity 5 is 1 / 4 to 3 / 4 of the dimension of the support column in that direction; this limiting condition actually limits the amount of material removed by the arc notch, ensuring that there is material on the support column required for stress flow dispersion, guaranteeing the required strength, and at the same time, in terms of casting draft, it has a lower impact on the demolding of the planetary carrier.

[0036] One feasible implementation is that the edges between adjacent faces on the planetary carrier have rounded corners to avoid stress concentration at the edges between faces.

[0037] One feasible implementation method is as follows. Of course, other conventional structures are also provided on the planetary carrier, which will not be described in detail here.

[0038] The planetary carriers disclosed in Examples 1-3 above were verified under actual working conditions using finite element analysis; the verification results are as follows. Figure 6 , Figure 7 As shown, it can be determined that: a) Static strength analysis: Under extreme torque conditions, the peak Von Mises stress in the connection area is 271.4 MPa, and the safety factor meets the requirements of the GL wind power specification. b) Fatigue life prediction: Based on the SN curve of the GL2010 wind power standard and the Miner linear cumulative damage criterion, the minimum fatigue life is predicted to meet the 20-year design life requirement, and there is no risk of fatigue failure in the critical connection area. c) Interference verification: Sufficient safety clearance is maintained in all working positions of the planetary gears (including the most unfavorable combination of manufacturing tolerances and thermal expansion) without any risk of interference.

[0039] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A high-strength, high-rigidity planetary carrier, comprising a front side plate (1), a rear side plate (2), and a plurality of support columns, wherein the front side plate (1) and the rear side plate (2) are arranged axially; the support columns are disposed between the front side plate (1) and the rear side plate (2) and located at the outer edges of the front side plate (1) and the rear side plate (2), forming a cavity (5) for accommodating gears in conjunction with the front side plate (1) and the rear side plate (2); characterized in that: The support column protrudes outward from the cavity (5) and has a first arc-shaped surface (32) located on the inner side and protruding outward and a second arc-shaped surface (33) located on the outer side and protruding outward; the first arc-shaped surface (32) and the second arc-shaped surface (33) are both smoothly transitioned with the front side plate (1) and the rear side plate (2); in the circumferential direction of the cavity (5), the two sides of the support column have concave arc-shaped edges (31) that smoothly transition with the inner surfaces of the front side plate (1) and the rear side plate (2).

2. The planetary carrier according to claim 1, characterized in that: In the circumferential direction of the cavity (5) and on the first arc surface (32), the distance from the point where the arc edge (31) smoothly transitions to the inner surface of the front side plate (1) and the rear side plate (2) to the deepest point of the arc edge (31) is a, and the size of a is 1 / 8 to 1 / 4 of the length of the first arc surface (32) in the circumferential direction; in the axial direction of the cavity (5), the maximum width of the arc edge (31) is b; and a / b ≥ 1 / 2.

3. The planetary carrier according to claim 1, characterized in that: The first arc surface (32) is C-shaped or U-shaped; and / or the second arc surface (33) is C-shaped or U-shaped; and / or the arc edge (31) is C-shaped or U-shaped.

4. The planetary carrier according to claim 1, characterized in that: The plurality of the support columns are arranged circumferentially along the cavity (5).

5. The planetary carrier according to claim 1, characterized in that: The first arc surface (32) is smaller in the circumferential direction than the second arc surface (33) so that the two sides of the support column have inclined surfaces (34) in the circumferential direction of the cavity (5). The inclined surfaces (34) are arc surfaces that match the degree of arc of the arc edge (31). The inclined surfaces (34) smoothly transition with the inner surfaces of the front side plate (1) and the rear side plate (2).

6. The planetary carrier according to any one of claims 1-5, characterized in that: The smooth transition can be either a rounded corner smooth transition or a tangent smooth transition.

7. The planetary carrier according to any one of claims 1-5, characterized in that: The outer surfaces of the front side plate (1) and the rear side plate (2) have arc-shaped notches at the connection with the support column. The arc-shaped notches are located between the two arc-shaped edges (31) on the support column.

8. The planetary carrier according to claim 7, characterized in that: The arc-shaped notch is located at the connection between the support column and the front side plate (1), and the support column and the rear side plate (2), and has the function of removing material from the front side plate (1), the support column and the rear side plate (2).

9. The planetary carrier according to claim 7, characterized in that: After setting the arc-shaped notch, the dimension c of the residual material on the first arc-shaped surface (32) in the axial direction of the cavity (5) is 1 / 4 to 3 / 4 of the dimension of the support column in that direction.

10. The planetary carrier according to claim 1, characterized in that: The edges between adjacent faces on the planetary mount have rounded corners.

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