Two-stage planetary gear assembly and assembling method and correcting tool for assembling two-stage planetary gear assembly

Abstract

The invention discloses a two-stage planetary gear assembly, an assembling method of the two-stage planetary gear assembly and a correction tool for assembling. The two-stage planetary gear assembly comprises a duplex planetary gear unit, a sun gear, a fixed gear ring and a movable gear ring. The duplicate planetary gear unit comprises a planetary gear support and at least three duplicate gear sets which are evenly arranged in the planetary gear support in the circumferential direction. Each duplicate gear set comprises a large gear and a small gear which are coaxially connected; the large gear and the small gear in each duplicate gear set are respectively provided with at least one positioning tooth, and the orthographic projection of the symmetrical center line of the tooth profile of the corresponding positioning tooth in the large gear and the small gear in the axial direction coincides with the orthographic projection of the symmetrical center line of the tooth profile of the corresponding positioning tooth in the axial direction in the axial direction. The sun gear is arranged on the inner sides of the at least three bull gears and is meshed with each bull gear at the same time; teeth, meshed with the sun gear, of the at least three large gears are evenly distributed in the circumferential direction of the sun gear. The fixed gear ring is arranged on the outer sides of the at least three bull gears and is meshed with each bull gear at the same time; the movable gear ring is arranged on the outer sides of the at least three pinions and meshed with the pinions at the same time.

Description

Technical Field

[0001] This invention relates to the field of gearbox technology, and more particularly to a two-stage planetary gear assembly, its assembly method, and the calibration fixture used for assembly. Background Technology

[0002] Planetary gear reduction structures are generally single-stage or multi-stage transmissions. For two-stage or higher transmissions, a combination of a fixed ring gear and multiple planetary gears is often used. A typical example is a two-stage planetary gear transmission, where the first-stage planetary gear is paired with a fixed ring gear, and the second-stage planetary gear is paired with a moving ring gear. Inside the first-stage planetary gear, there is also a sun gear. After assembly, an external input shaft drives the sun gear to rotate. The sun gear drives the first-stage planetary gear to rotate, causing the second-stage planetary gear, which rotates synchronously with the first-stage planetary gear, to rotate with the moving ring gear, thereby driving the output shaft to rotate.

[0003] In the aforementioned two-stage planetary gear transmission process, in one existing technology, a fixed gear is configured inside the second-stage planetary gear to mesh with it. This limits the second-stage planetary gear to the position between the moving gear ring and the fixed gear (for each second-stage planetary gear, the meshing points with the fixed gear ring and the moving gear ring are symmetrically located on both sides of the rotation center of the planetary gear to ensure reliable and stable operation of the moving gear ring). This ensures reliable operation of the moving gear ring under the action of the second-stage planetary gear. In this case, on the one hand, an additional fixed gear needs to be designed, which increases the overall cost of the product. On the other hand, the second-stage planetary gear needs to form a precise fit with both the moving gear ring and the fixed gear to ensure smooth operation. Therefore, the more components there are, the higher the requirements for assembly accuracy and product precision.

[0004] Based on the above, in the second optional implementation, the fixed gear is eliminated, so that the second-stage planetary gear only meshes with the moving ring gear, without a fixed gear inside. This simplifies the structure, reduces assembly steps, and lowers assembly difficulty. However, in this case, since there is no fixed gear inside the second-stage planetary gear for positioning, and the moving ring gear rotates synchronously with the second-stage planetary gear, if the multiple gears of the second-stage planetary gear, which lack a fixed positioning function, cannot guarantee a reliable meshing state with the moving ring gear, it may cause uneven force on the moving ring gear, affecting the stability of the moving ring gear's operation, and also generating operating noise between the moving ring gear and the second-stage planetary gear.

[0005] Therefore, for the case where the fixed gear is eliminated in the second-stage planetary gear, ensuring that multiple gears of the second-stage planetary gear simultaneously form a reliable meshing state with the moving gear ring (for multiple second-stage planetary gears, their meshing points with the moving gear ring must be evenly distributed along the circumference) is a technical challenge that needs to be overcome, thereby balancing structural simplification and operational reliability. For example, CN205155102U discloses a planetary transmission system for an excavator travel motor reducer, which improves gear meshing by optimizing the tooth profile of the double planetary gears, preventing uneven load distribution, improving transmission smoothness, and reducing transmission noise. While this planetary transmission system can improve transmission smoothness, it requires precise design of the gear tooth profile, placing high demands on gear manufacturing precision (high requirements for controlling tooth misalignment), thus making overall production relatively difficult. Therefore, to balance structural simplification and operational reliability, it is also necessary to consider reducing production difficulty.

[0006] Therefore, to address the issue of reducing noise and improving the reliability of two-stage planetary gear reduction structures while lowering the requirements for gear manufacturing precision, further optimization and improvement of the existing structure and assembly methods of two-stage planetary gear assemblies are needed. Summary of the Invention

[0007] The primary objective of this invention is to provide a two-stage planetary gear assembly that addresses the technical problem of balancing structural simplification and operational reliability while reducing manufacturing complexity.

[0008] The second objective of this invention is to provide a method for assembling a two-stage planetary gear assembly, thereby solving the technical problem of balancing structural simplification and operational reliability while reducing production difficulty.

[0009] A third objective of this invention is to provide a calibration fixture for assembling a two-stage planetary gear assembly, in order to solve the technical problem of rapidly calibrating the meshing position of the gears in each double-gear set of the two-stage planetary gear assembly.

[0010] The two-stage planetary gear assembly of the present invention is implemented as follows: A two-stage planetary gear assembly, comprising: A double planetary gear unit includes a planetary gear carrier and at least three double gear sets uniformly arranged circumferentially within the planetary gear carrier; each double gear set includes a large gear and a small gear coaxially connected; each large gear and small gear in each double gear set has at least one positioning tooth formed on it, and the symmetrical center lines of the tooth profiles of the corresponding positioning teeth on the large gear and small gear along the axial direction coincide in the orthogonal projection along the axial direction; each large gear and / or small gear in each double gear set is provided with an identification part corresponding to one of the positioning teeth; The sun gear is located inside at least three large gears and meshes with each large gear simultaneously, and the teeth of the at least three large gears meshing with the sun gear are evenly distributed along the circumference of the sun gear; the planet gear support is pre-set with mounting holes suitable for the sun gear to pass through. A fixed gear ring, which is located on the outside of at least three large gears and meshes with each of the large gears simultaneously; A moving gear ring, which is located outside at least three pinions and meshes with each pinion simultaneously.

[0011] In an optional embodiment of the invention, the identification part is disposed on the large gear; and The identification part is a structure that is recessed or raised on the shaft side end of the large gear facing away from the small gear.

[0012] In an optional embodiment of the present invention, the identification part is located at the root of the positioning tooth of the large gear.

[0013] In an optional embodiment of the present invention, the planetary gear support includes a first support and a second support adapted to be spliced ​​together; wherein Both the first bracket and the second bracket include a circular shaft end plate and a plurality of extension columns at one axial end of the circular shaft end plate; The extension columns of the first bracket and the second bracket are suitable for assembly and connection.

[0014] In an optional embodiment of the invention, the circular shaft end plate of the first bracket is located on the side of each double gear set where the large gear faces away from the small gear, and the circular shaft end plate of the second bracket is located on the side of each double gear set where the small gear faces away from the large gear; and Each of the aforementioned double gear sets is supported in a planetary gear bracket by a planetary shaft, and the two ends of the planetary shaft are respectively fixedly connected to the circular shaft end plates of the first bracket and the second bracket.

[0015] In an optional embodiment of the invention, the moving gear ring is connected to the circular shaft end plate of the second bracket via a positioning shaft.

[0016] In an optional embodiment of the present invention, the circular shaft end plate of the second bracket is further provided with a positioning post protruding toward the first bracket for axial positioning of the sun gear.

[0017] In an optional embodiment of the invention, at least a portion of the outer circular wall surface of the large gear in each of the double gear sets protrudes from the outer circular wall surface of the circular shaft end plate of the first support; and At least a portion of the outer circular wall surface of the pinion of each of the said double gear sets protrudes from the outer circular wall surface of the circular shaft end plate of the second bracket.

[0018] The assembly method of the two-stage planetary gear assembly of the present invention is implemented as follows: A method for assembling a two-stage planetary gear assembly, comprising: Step S1: Assemble each double gear set into place with the planetary gear carrier; Step S2: Use a calibration fixture to position the identification part of each double gear set so that the identification parts of at least three double gear sets are evenly distributed along the circumferential direction, thereby calibrating the positions of the large gear and small gear of each double gear set meshing with the fixed gear ring and the moving gear ring, respectively. Step S3: After the positions of the large and small gears of each double gear set meshing with the fixed and moving gear rings are corrected, insert the sun gear into the mounting hole of the planet gear holder until the sun gear meshes with each large gear simultaneously, and then remove the correction fixture. Step S4: Assemble the double planetary gear unit with the moving gear ring and the fixed gear ring in sequence.

[0019] The alignment fixture for assembling the two-stage planetary gear assembly of the present invention is implemented as follows: A calibration fixture for assembling a two-stage planetary gear assembly, applicable to the assembly method of the two-stage planetary gear assembly, includes: an annular support plate and multiple positioning parts disposed on the annular support plate for corresponding identification parts of each double-gear set; Multiple positioning parts are evenly arranged along the circumference.

[0020] In an optional embodiment of the present invention, the identification part is a positioning blind hole provided on the large gear and / or small gear; The positioning part is a positioning pin suitable for insertion into the positioning blind hole; the annular support plate is provided with an adapter hole that slides with the positioning pin. An elastic element is provided between the positioning pin and the adapter hole, so that the positioning pin is adapted to slide relative to the adapter hole to enter and exit the positioning blind hole.

[0021] In an optional embodiment of the invention, the annular support plate has a through hole suitable for the sun gear to pass through.

[0022] By adopting the above technical solution, the present invention has the following beneficial effects: The double-stage planetary gear assembly, its assembly method, and the calibration fixture for assembly of the present invention, for the double planetary gear unit, can use the positioning tooth engagement identification part designed on the large gear and small gear in each double gear set to calibrate the meshing position with the fixed gear ring and the moving gear ring through the calibration fixture, thereby ensuring that the meshing positions of the small gears corresponding to the multiple double gear sets and the moving gear ring are evenly arranged in the circumferential direction. This allows the multiple small gears to generate a balanced rotational force on the moving gear ring, preventing the moving gear ring from being subjected to uneven load, thereby improving the smoothness of the moving gear ring transmission and reducing transmission noise.

[0023] Furthermore, for the calibration fixture, the calibration of the large and small gears of the double gear set can be achieved simply by cooperating with the identification part in the double gear set. The operation is convenient, efficient, and easy. Attached Figure Description

[0024] Figure 1 This is an exploded structural diagram of the two-stage planetary gear assembly of the present invention; Figure 2 This is an exploded structural diagram of the double planetary gear unit of the double-stage planetary gear assembly of the present invention. Figure 3 This is a cross-sectional view of the two-stage planetary gear assembly of the present invention; Figure 4 This is a schematic diagram of the structure of the double gear set of the double-stage planetary gear assembly of the present invention; Figure 5 This is a schematic diagram of the positioning teeth of the double gear set in the double-stage planetary gear assembly of the present invention. Figure 6 This is a schematic diagram of the structure of the two-stage planetary gear assembly of the present invention with the positioning teeth of the three double gear sets in the corrected position. Figure 7 This is a schematic diagram of the mating structure between the double planetary gear unit and the calibration fixture in the double-stage planetary gear assembly of the present invention. Figure 8 This is a schematic diagram of the alignment fixture used for assembling the two-stage planetary gear assembly of the present invention; Figure 9 This is a cross-sectional view of the alignment fixture used for assembling the two-stage planetary gear assembly of the present invention. Figure 10 This is a schematic diagram of the assembly of the sun gear during the assembly process of the two-stage planetary gear assembly of the present invention; Figure 11 This is a schematic diagram of the structure of the double planetary gear unit and the moving gear ring of the double-stage planetary gear assembly of the present invention when they are assembled in place. Figure 12This is a schematic diagram of the structure of the double planetary gear unit and the fixed gear ring of the double-stage planetary gear assembly of the present invention when they are assembled in place. Figure 13 This is a schematic diagram of the mating structure between the fixed gear ring and the outer shell of the two-stage planetary gear assembly of the present invention.

[0025] In the diagram: outer shell 1, annular step 11, sun gear 2, fixed gear ring 3, moving gear ring 4, large gear 51, small gear 52, first bracket 531, mounting hole 532, second bracket 533, circular shaft end plate 54, extension column 55, positioning column 56, positioning shaft 57, positioning tooth 58, positioning blind hole 59, planetary shaft 510, annular support plate 61, positioning pin 62, adapter hole 63, elasticity 64, bolt 65, through hole 66, chamfer K, output shaft 7, bearing 8, groove 91, convex strip 92, end cover 100. Detailed Implementation

[0026] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0027] Example 1: Please see Figures 1 to 13 As shown, this embodiment provides a two-stage planetary gear assembly, including a mating double planetary gear unit, a sun gear 2, a fixed ring gear 3, a moving ring gear 4, an output shaft 7 connected to the moving ring gear 4, and an outer housing 1 for accommodating the double planetary gear unit, the sun gear 2, the fixed ring gear 3, and the moving ring gear 4. The moving ring gear 4 is rotatably engaged with the outer housing 1 via a bearing 8, while the fixed ring gear 3 is fixed within the outer housing 1.

[0028] Next, we will focus on the specifics. First, the double planetary gear unit includes a planetary gear carrier and at least three double gear sets evenly arranged circumferentially within the planetary gear carrier. This can involve three or four double gear sets; this embodiment, in conjunction with the accompanying drawings, illustrates a design with three double gear sets for detailed explanation.

[0029] Furthermore, each double gear set includes a large gear 51 and a small gear 52 coaxially connected. The outer diameters of the large gear 51 and the small gear 52 are different; the outer diameter of the large gear 51 is larger than that of the small gear 52. In an optional embodiment, the large gear 51 and the small gear 52 of each double gear set are integrally formed using powder metallurgy. In this embodiment, the module of the large gear 51 and the small gear 52 is no greater than 2, preferably 0.15 to 0.7 (the smaller the module, the more teeth, and the more difficult it is to determine the meshing teeth visually).

[0030] The sun gear 2 is located inside the three large gears 51 and meshes with each of them simultaneously. The teeth of the three large gears 51 meshing with the sun gear 2 are evenly distributed along the circumference of the sun gear 2. For assembly purposes, the planetary gear carrier has pre-set mounting holes 532 suitable for the sun gear 2 to pass through. The fixed ring gear 3 is located outside the three large gears 51 and meshes with each of them simultaneously. The movable ring gear 4 is located outside the three small gears 52 and meshes with each of them simultaneously. An external power input drives the sun gear 2 to rotate. The fixed ring gear 3 is fixed inside the outer casing 1. The rotation of the double planetary gear unit causes the movable ring gear 4 to rotate and decelerate. The output shaft 7 transmits the amplified torque after deceleration.

[0031] More specifically, the planetary gear support used in this embodiment includes a first support 531 and a second support 533 suitable for splicing and connecting; wherein both the first support 531 and the second support 533 include a circular shaft end plate 54 and a plurality of extension columns 55 on one axial side end of the circular shaft end plate 54; the extension columns 55 of the first support 531 and the second support 533 are suitable for splicing and connecting. In an optional embodiment, the extension columns 55 of the first support 531 and the second support 533 are connected by rivets to increase axial tensile force and further improve stability and accuracy.

[0032] Furthermore, the circular shaft end plate 54 of the first bracket 531 is located on the side of the large gear 51 of each double gear set facing away from the small gear 52, and the circular shaft end plate 54 of the second bracket 533 is located on the side of the small gear 52 of each double gear set facing away from the large gear 51; and each double gear set is supported in the planetary gear carrier by a planetary shaft 510, and the two ends of the planetary shaft 510 are respectively fixedly connected to the circular shaft end plates 54 of the first bracket 531 and the second bracket 533. Here, the two ends of the planetary shaft 510 can be optionally interference-fitted to the circular shaft end plates 54 of the first bracket 531 and the second bracket 533, respectively. Mounting hole 532 is provided on the circumferential shaft end plate of the first bracket 531. Accordingly, it should also be noted that, in order to improve the reliability and stability of the sun gear 2's operation, a positioning post 56 protruding towards the first bracket 531 is also provided on the circular shaft end plate 54 of the second bracket 533 for axial positioning of the sun gear 2. The positioning post 56 and the sun gear 2 are in a rotational fit, which does not affect the normal operation of the sun gear 2, and can also play the role of axial positioning of it.

[0033] In one alternative implementation, the movable gear ring 4 is connected to the circular shaft end plate 54 of the second bracket 533 via a positioning shaft 57. The positioning shaft 57 is designed to prevent excessive axial runout of the movable gear ring 4 during high-speed operation. Since the movable gear ring 4 is fixed to the output shaft 7, the positioning shaft 57 can also be connected to the output shaft 7, similarly preventing excessive axial runout of the movable gear ring 4. When both the positioning pin 56 and the positioning shaft 57 are designed, the positioning shaft 57 can be directly assembled with the positioning pin 56, requiring only a shaft hole within the positioning pin 56 for inserting the positioning shaft 57.

[0034] In addition, in order to better adapt the large gear 51 to the fixed gear ring 3 and the small gear 52 to the moving gear ring 4, at least part of the outer circular wall surface of the large gear 51 of each double gear set protrudes from the outer circular wall surface of the circular shaft end plate 54 of the first bracket 531; and at least part of the outer circular wall surface of the small gear 52 of each double gear set protrudes from the outer circular wall surface of the circular shaft end plate 54 of the second bracket 533.

[0035] Based on the above, it needs to be further explained that, in order to achieve a unified meshing transmission reference between the large gear 51 and the small gear 52 in each double gear set, at least one positioning tooth 58 is formed on each of the large gear 51 and the small gear 52 in each double gear set, and the symmetrical center lines of the tooth profiles of the corresponding positioning teeth 58 along the axial direction of the large gear 51 and the small gear 52 coincide in the orthographic projection along the axial direction. From the perspective of simplifying the structure, one positioning tooth 58 is formed on each of the large gear 51 and the small gear 52 in each double gear set, and the positioning teeth 58 of the large gear 51 and the small gear 52 coincide in the orthographic projection along the axial direction of the double gear set. Based on this, the remaining teeth of the large gear 51 and the small gear 52 can be arranged at a uniform angle in the circumferential direction according to the design parameters.

[0036] Based on the above structure, each double-gear set has an identification part on the large gear 51 and / or small gear 52 corresponding to the positioning tooth 58; thus, the position of the positioning tooth 58 can be clearly found through the identification part. The design of the identification part here is mainly to improve the accuracy and assembly efficiency of the double-planetary gear unit with the fixed gear ring 3 and the moving gear ring 4.

[0037] In this regard, let's take an example of an optional implementation, with reference to the attached diagram. The identification part is only provided on the large gear 51; as for the shape of the identification part, it can be understood that it can be a structure that is recessed or raised on the shaft side end of the large gear 51 facing away from the small gear 52.

[0038] In terms of the specific design location of the identification part, the identification part is located at the root of the positioning tooth 58 of the large gear 51.

[0039] In summary, for the double-stage planetary gear assembly of this embodiment, the positioning teeth 58 designed on the large gear 51 and small gear 52 in each double gear set can be used to identify the meshing position of the large gear 51 with the fixed gear ring 3 and the moving gear ring 4 by the correction fixture. This ensures that the meshing positions of the small gears 52 and the moving gear ring 4 corresponding to the multiple double gear sets are evenly arranged in the circumferential direction. This allows the multiple small gears 52 to generate a balanced rotational force on the moving gear ring 4, preventing the moving gear ring 4 from being subjected to uneven load, thereby improving the smoothness of the transmission of the moving gear ring 4 and reducing transmission noise.

[0040] Example 2: Please see Figures 1 to 13 As shown, based on the two-stage planetary gear assembly of Embodiment 1, this embodiment provides an assembly method for assembling the two-stage planetary gear assembly of Embodiment 1. Specifically, the assembly method includes the following steps: Step S1: Assemble each double gear set with the planetary gear carrier. During this process, the three planetary shafts 510 are passed through the double gear sets respectively, and the first carrier 531 and the second carrier 533 are fixed to both ends of the three planetary shafts 510 respectively. In this embodiment, the first carrier 531 and the second carrier 533 form a support for the double gear sets, thereby allowing the double planetary gear unit to be formed as a whole for easy assembly with the fixed gear ring 3 and the moving gear ring 4, improving assembly efficiency and accuracy.

[0041] Step S2: Use a calibration fixture to position the identification part of each double gear set so that the identification parts of at least three double gear sets are evenly distributed along the circumferential direction, thereby calibrating the positions of the large gear 51 and small gear 52 of each double gear set meshing with the fixed gear ring 3 and the moving gear ring 4, respectively.

[0042] Step S3: After the positions of the large gear 51 and small gear 52 of each double gear set meshing with the fixed gear ring 3 and the moving gear ring 4 are corrected, insert the sun gear 2 into the mounting hole 532 of the planet gear bracket until the sun gear 2 meshes with each large gear 51 at the same time, and then remove the correction fixture.

[0043] During this process, since the position of the positioning teeth 58 of the large gears 51 of the three double gear sets has been corrected under the action of the correction fixture, the meshing of the tooth surfaces of the large gears 51 of the three double gear sets with the sun gear 2 can simultaneously enter the correct meshing angle during the installation of the sun gear 2. This results in high assembly efficiency and high precision in meshing angle positioning. After the sun gear 2 is installed, the relative angles between the large gears 51 of the three double gear sets are already determined. Therefore, after removing the correction fixture, although each large gear 51 in the three double gear sets will rotate at a certain angle, the relative angles of the large gears 51 of the three double gear sets remain unchanged. Thus, the accuracy of the assembly position of the three double gear sets with the moving gear ring 4 and the fixed gear ring 3 can be ensured. That is, the meshing points of the three small gears 52 with the moving gear ring 4 are evenly distributed along the circumferential direction. Similarly, the meshing points of the three large gears 51 with the fixed gear ring 3 are evenly distributed along the circumferential direction.

[0044] Step S4: Assemble the double planetary gear unit with the moving gear ring 4 and the fixed gear ring 3 in sequence. In this process, the double planetary gear unit is assembled with the moving gear ring 4 first. Since the moving gear ring 4 is assembled inside the outer casing 1, the double planetary gear unit is inserted into the outer casing 1 so that the pinion 52 of the double planetary gear unit can mesh with the moving gear ring 4. During the insertion process, when the tooth profile of the pinion 52 contacts the tooth surface of the moving gear ring 4, the insertion direction and angle of the double planetary gear unit are adjusted appropriately. The pinions 52 of the three double gear sets can simultaneously engage with the tooth surfaces of the moving gear ring 4 at the correct meshing angle, resulting in high assembly efficiency and precise meshing angle positioning.

[0045] For the assembly process of the fixed gear ring 3 and the outer shell 1, in terms of the axial direction of the fixed gear ring 3, an annular step 11 is provided on the inner wall of the outer shell 1 to abut against one axial end of the fixed gear ring 3. In terms of the circumferential positioning of the fixed gear ring 3, it is achieved by at least one concave-convex fitting structure between the fixed gear ring 3 and the inner wall of the outer shell 1. The concave-convex fitting structure can be formed by forming a groove 91 on the inner wall of the outer shell 1 and forming a protrusion 92 on the outer wall of the fixed gear ring 3, thereby reliably fixing the fixed gear ring 3 in the outer shell 1 and preventing it from rotating with the operation of the three double gear sets.

[0046] It is also necessary to note that the entire double-stage planetary gear assembly involved in this embodiment also includes an end cover 100 that cooperates with the outer casing 1. After the assembly of the fixed gear ring 3 is completed in step S4, before the end cover 100 is assembled, an appropriate amount of lubricating grease can be injected into the gaps between the three double gear sets, between the planet gear and the large gear 51 and the fixed gear ring 3, and between the small gear 52 and the moving gear ring 4. After the end cover 100 is assembled, a certain period of running-in is performed to evenly distribute the lubricating grease on the meshing tooth surface.

[0047] In summary, regarding the assembly process of the two-stage planetary gear assembly in this embodiment, after the double planetary gear unit has completed its assembly with the sun gear 2, it is assembled integrally with the moving gear ring 4 and the fixed gear ring 3. This not only ensures high assembly efficiency but also avoids the problem of low installation accuracy and repeated adjustments caused by distributing each double gear set.

[0048] Example 3: Please see Figures 1 to 13 As shown, based on the assembly method of the double-stage planetary gear assembly in Embodiment 2, this embodiment provides a correction fixture for assembling a double-stage planetary gear assembly, which is applicable to the assembly method of the double-stage planetary gear assembly in Embodiment 2. The correction fixture includes: an annular support plate 61 and multiple positioning parts disposed on the annular support plate 61 for corresponding identification parts of each double-gear set; the multiple positioning parts are evenly arranged along the circumferential direction.

[0049] In the case of a two-stage planetary gear assembly using three double-gear sets, three positioning parts can be designed on the annular support plate 61. In this case, the central angle formed by any two adjacent positioning parts is 120° (when four positioning parts are designed for four double-gear sets, the central angle formed by any two adjacent positioning parts is 90°; that is, as long as the sum of the central angles formed by any two adjacent positioning parts is 360°, the usage requirements of this embodiment are met). Accordingly, when the three positioning parts correspond to the identification parts of each double-gear set, the positioning teeth 58 on the large gear 51 of the three double-gear sets form an equilateral triangle structure, i.e., the central angle formed between any two adjacent positioning teeth 58 is 120°. Thus, when the small gears 52 of the three double-gear sets simultaneously engage with the moving gear ring 4, the three small gears 52 can exert a balanced force on the moving gear ring 4, ensuring that the moving gear ring 4 is evenly stressed during operation, thereby improving the reliability and stability of the moving gear ring 4's operation.

[0050] In this regard, referring to the accompanying drawings, one optional embodiment is provided with a positioning blind hole 59 on the large gear 51 and / or the small gear 52; the positioning part is a positioning pin 62 adapted to be inserted into the positioning blind hole 59; the annular support plate 61 is provided with a fitting hole 63 that slides with the positioning pin 62. Here, in order to improve the convenience of inserting the positioning pin 62 into the positioning blind hole 59, the opening of the positioning blind hole 59 may be provided with a chamfer K.

[0051] Based on the above structure, a spring element 64 is provided between the locating pin 62 and the adapter hole 63, so that the locating pin 62 can slide relative to the adapter hole 63 to enter and exit the locating blind hole 59. The spring element 64 can be selected as a spring. The locating pin 62 is preferably T-shaped, so that one end is always kept in the adapter hole 63 and there is no problem of the locating pin 62 disengaging from the adapter hole 63. The adapter hole 63 can be a through hole extending axially along the annular support plate 61, with a large-diameter opening at the shaft end facing away from the large gear 51 to facilitate the installation of the locating pin 62 and the spring element 64. A bolt 65 can be used to form a stop for one end of the spring element 64. The shaft end of the adapter hole 63 facing the large gear 51 has a small-diameter opening, so that the locating pin 62 can partially extend out of the adapter hole 63 to form a positioning fit with the locating hole on the large gear 51.

[0052] Furthermore, it should be noted that the annular support plate 61 has a through hole 66 suitable for the sun gear 2 to pass through. In other words, the engagement between the sun gear 2 and the multiple large gears 51 is achieved when the positioning blind hole 59 of the large gear 51 and the positioning pin 62 are properly assembled. Specifically, the sun gear 2 is installed under the premise that the positions of the positioning teeth 58 of the multiple large gears 51 are precisely positioned by the calibration fixture. This not only allows for rapid and reliable meshing between the sun gear 2 and the multiple large gears 51, but also improves the accuracy of the meshing point position formed by the large gears 51 and the sun gear 2.

[0053] The specific usage process of the calibration fixture in this embodiment is as follows: The double planetary gear unit is placed on the calibration fixture, so that the end face of the large gear 51 with the positioning blind hole 59 is opposite to the end face of the annular support plate 61 with the positioning pin 62. At this time, when the positioning blind hole 59 of the large gear 51 is not aligned with the positioning pin 62, the shaft end face of the large gear 51 will press against the positioning pin 62, causing the positioning pin 62 to be compressed and compress the elastic element 64, thereby allowing the entire positioning pin 62 to be received into the fitting hole 63. Then, the large gears 51 of the three double gear sets are manually rotated sequentially. When the positioning blind hole 59 of each large gear 51 is aligned with the positioning pin 62 of the annular support plate 61, the positioning pin 62 enters the positioning hole under the thrust of the elastic element 64. This completes the process of the calibration fixture identifying and positioning the positioning teeth 58 of the large gears 51 of the double gear sets.

[0054] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0055] In the description of this invention, it should be understood that the terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element 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 invention.

[0056] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0057] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., 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 of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element 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 invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0058] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they 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.

[0059] In this invention, unless otherwise expressly specified and limited, "above or below" a first feature may include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on" the first feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the first feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

Claims

1. A two-stage planetary gear assembly, characterized in that, include: A double planetary gear unit includes a planetary gear carrier and at least three double gear sets uniformly arranged circumferentially within the planetary gear carrier; each double gear set includes a large gear and a small gear coaxially connected; each large gear and small gear in each double gear set has at least one positioning tooth formed on it, and the symmetrical center lines of the tooth profiles of the corresponding positioning teeth on the large gear and small gear along the axial direction coincide in the orthogonal projection along the axial direction; each large gear and / or small gear in each double gear set is provided with an identification part corresponding to one of the positioning teeth; The sun gear is located inside at least three large gears and meshes with each large gear simultaneously, and the teeth of the at least three large gears meshing with the sun gear are evenly distributed along the circumference of the sun gear; the planet gear support is pre-set with mounting holes suitable for the sun gear to pass through. A fixed gear ring, which is located on the outside of at least three large gears and meshes with each of the large gears simultaneously; A moving gear ring, which is located outside at least three pinions and meshes with each pinion simultaneously.

2. The two-stage planetary gear assembly according to claim 1, characterized in that, The identification unit is located on the large gear; and The identification part is a structure that is recessed or raised on the shaft side end of the large gear facing away from the small gear.

3. The two-stage planetary gear assembly according to claim 2, characterized in that, The identification part is located at the root of the positioning tooth of the large gear.

4. The two-stage planetary gear assembly according to any one of claims 1 to 3, characterized in that, The planetary gear support includes a first support and a second support suitable for splicing and connecting; wherein Both the first bracket and the second bracket include a circular shaft end plate and a plurality of extension columns at one axial end of the circular shaft end plate; The extension columns of the first bracket and the second bracket are suitable for assembly and connection.

5. The two-stage planetary gear assembly according to claim 4, characterized in that, The circular shaft end plate of the first bracket is located on the side of the large gear facing away from the small gear in each double gear set, and the circular shaft end plate of the second bracket is located on the side of the small gear facing away from the large gear in each double gear set. as well as Each of the aforementioned double gear sets is supported in a planetary gear bracket by a planetary shaft, and the two ends of the planetary shaft are respectively fixedly connected to the circular shaft end plates of the first bracket and the second bracket.

6. The two-stage planetary gear assembly according to claim 5, characterized in that, The movable gear ring is connected to the circular shaft end plate of the second bracket via a positioning shaft.

7. The two-stage planetary gear assembly according to claim 5, characterized in that, The circular shaft end plate of the second bracket is also provided with a positioning post that protrudes toward the first bracket for axial positioning of the sun gear.

8. The two-stage planetary gear assembly according to claim 5, characterized in that, At least a portion of the outer circular wall surface of the large gear in each of the said double gear sets protrudes from the outer circular wall surface of the circular shaft end plate of the first bracket; as well as At least a portion of the outer circular wall surface of the pinion of each of the said double gear sets protrudes from the outer circular wall surface of the circular shaft end plate of the second bracket.

9. A method for assembling a two-stage planetary gear assembly, characterized in that, For assembling a two-stage planetary gear assembly as described in any one of claims 1 to 8, comprising: Step S1: Assemble each double gear set into place with the planetary gear carrier; Step S2: Use a calibration fixture to position the identification part of each double gear set so that the identification parts of at least three double gear sets are evenly distributed along the circumferential direction, thereby calibrating the positions of the large gear and small gear of each double gear set meshing with the fixed gear ring and the moving gear ring, respectively. Step S3: After the positions of the large and small gears of each double gear set meshing with the fixed and moving gear rings are corrected, insert the sun gear into the mounting hole of the planet gear holder until the sun gear meshes with each large gear simultaneously, and then remove the correction fixture. Step S4: Assemble the double planetary gear unit with the moving gear ring and the fixed gear ring in sequence.

10. A calibration fixture for assembling a two-stage planetary gear assembly, characterized in that, An assembly method applicable to the double-stage planetary gear assembly as described in claim 9 includes: an annular support plate and a plurality of positioning portions disposed on the annular support plate for corresponding to the identification portions of each double-gear set; Multiple positioning parts are evenly arranged along the circumference.

11. The alignment fixture for assembling a two-stage planetary gear assembly according to claim 10, characterized in that, The identification part is a positioning blind hole provided on the large gear and / or small gear; The positioning part is a positioning pin suitable for insertion into the positioning blind hole; the annular support plate is provided with an adapter hole that slides with the positioning pin. An elastic element is provided between the positioning pin and the adapter hole, so that the positioning pin is adapted to slide relative to the adapter hole to enter and exit the positioning blind hole.

12. The alignment fixture for assembling a two-stage planetary gear assembly according to claim 10 or 11, characterized in that, The annular support plate has through holes suitable for the sun gear to pass through.

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