Double toothed structure and gear box

Abstract

The utility model relates to a double gear structure and gear box relates to mechanical drive technical field, it includes first planetary gear and second planetary gear, first planetary gear is provided with assembly hole, first planetary gear has first side and second side, a plurality of first recesses are provided on first side, a plurality of second recesses are provided on second side, a plurality of first recesses and a plurality of second recesses are sequentially arranged in alternation in the circumference of first planetary gear, the distance between first side and second side gradually reduces in the direction from the center of first planetary gear to the periphery, second planetary gear includes integral connecting axle section and gear body, and connecting axle section and gear body are coaxial arrangement, connecting axle section is inserted and fixed in assembly hole, and the side of gear body contacts first side or second side, it can improve structural strength, improve deformation resistance, increase inherent frequency, change modal shape, optimize noise reduction.

Description

Technical Field

[0001] This utility model relates to the field of mechanical transmission technology, and more specifically, to a double-tooth structure and a gearbox. Background Technology

[0002] In existing gearboxes, double gears are generally used to adjust the speed ratio. Existing double gears usually include a large gear and a small gear. The axle of the small gear is inserted into the center hole of the large gear, and the two are coaxially arranged.

[0003] The inventors discovered during their research that the existing double-tooth structure has at least the following drawbacks:

[0004] The spokes of the large gear are regular straight ring plates, which have poor resistance to bending deformation under the axial force of helical gear meshing. This results in large variations in the contact patch (i.e., peak-to-peak value of transmission error) on the tooth surface of the large gear under different load conditions, which is not conducive to gear noise reduction. At the same time, the spoke structure of the straight ring plate large gear is simple, making it difficult to increase the structural stiffness to increase the natural frequency while reducing weight, which is not conducive to frequency avoidance. Moreover, the mode shapes of similar structures are basically the same, which is not conducive to mode avoidance and easily leads to gear noise problems. In addition, the spokes of the straight ring plate large gear lack the function of optimizing lubrication. Utility Model Content

[0005] The objectives of this invention include, for example, providing a double-tooth structure and gearbox that can improve structural strength, enhance resistance to deformation, increase natural frequency, change mode shape, and optimize noise reduction.

[0006] The embodiments of this utility model can be implemented as follows:

[0007] In a first aspect, this utility model provides a double-tooth structure, comprising:

[0008] A first planetary gear and a second planetary gear, wherein the first planetary gear is provided with a mounting hole, and the first planetary gear has a first side and a second side opposite to each other in the axial direction of the mounting hole; a plurality of first grooves are provided on the first side, and a plurality of second grooves are provided on the second side, the plurality of first grooves and the plurality of second grooves being arranged alternately in the circumferential direction of the first planetary gear; the distance between the first side and the second side gradually decreases from the center of the first planetary gear to the periphery.

[0009] The second planetary gear includes an integral connecting shaft section and a gear body. The connecting shaft section is coaxially arranged with the gear body, and the outer diameter of the connecting shaft section is smaller than the tooth tip circle diameter of the gear body. The connecting shaft section is inserted and fixed in the mounting hole, and the side of the gear body contacts the first side or the second side.

[0010] In an optional embodiment, the first side is perpendicular to the axis of the first planetary gear, and the second side protrudes outward in a direction away from the first side, so that the distance between the first side and the second side gradually decreases from the center of the first planetary gear to the surrounding area.

[0011] The side of the gear body contacts the second side.

[0012] Based on the above scheme, the second side forms an outward convex structure, which can increase the contact area between the connecting shaft section and the first planetary gear, thereby improving the bonding strength; it can also improve the structural strength of the first planetary gear and enhance its resistance to deformation.

[0013] In an optional embodiment, a first oil guide hole is provided on the bottom wall of the first groove;

[0014] Or / and, a second oil guide hole is provided on the bottom wall of the second groove.

[0015] Based on the above scheme, the first oil guide hole, which is connected to the first groove, is used to throw oil to the right side of the gearbox. The lubricating oil can reach the tooth groove of the spline of the internal gear ring and the housing, which enhances the lubrication of the floating spline of the internal gear ring and reduces friction and noise. The second oil guide hole, which is connected to the second groove, is used to throw oil to the oil guide rib plate of the left side of the gearbox housing, which enhances the lubrication of the left bearing, oil seal and sun gear of the planetary carrier. In this way, both sides of the double gear structure can have sufficient lubricating oil to lubricate the corresponding parts, resulting in good lubrication effect, low wear and stable and reliable operation.

[0016] In an optional embodiment, a portion of the wall of the first oil guide hole overlaps with the groove sidewall of the first groove that is away from the axis of the first planetary gear.

[0017] Or / and, a portion of the wall of the second oil guide hole overlaps with the groove sidewall of the second groove away from the axis of the first planetary gear.

[0018] Based on the above scheme, when the first planetary gear rotates around its own axis, under the action of centrifugal force, the lubricating oil is concentrated at the position away from the groove side wall of the first planetary gear, which makes it easier for the lubricating oil to be discharged from the oil guide hole at this position, and the lubricating oil flows more smoothly and has a better lubrication effect.

[0019] In an optional embodiment, the assembly hole includes a communicating variable-diameter hole section and a constant-diameter hole section, with one end of the variable-diameter hole section away from the constant-diameter hole section located on the first side surface, and one end of the constant-diameter hole section away from the variable-diameter hole section located on the second side surface, wherein the diameter of the variable-diameter hole section gradually decreases in the direction from the first side surface to the second side surface.

[0020] Based on the above scheme, the location of the variable diameter hole section can form an annular groove with the outer circumferential surface of the connecting shaft section, which is conducive to accommodating the solder and resulting in a good welding effect.

[0021] In an optional embodiment, a chamfer is provided on the end face of the connecting shaft segment away from the gear body, and the chamfer cooperates with the variable diameter hole segment to form a solder receiving groove.

[0022] Based on the above solution, the connecting shaft segment, with its chamfered end, is inserted into the assembly hole, minimizing interference and making insertion easier and faster. Furthermore, the chamfered position, combined with the variable diameter hole segment, forms a larger solder receiving groove, resulting in higher weld strength.

[0023] In an optional embodiment, an air guide groove is provided on the outer peripheral surface of the connecting shaft segment;

[0024] The outer circumferential surface of the gear body is provided with tooth grooves, and the air guide groove is connected to the corresponding tooth grooves.

[0025] Based on the above scheme, the hot gas flow and residue generated during welding can smoothly enter the tooth groove from the gas guide groove and then be discharged. The gas guide groove can be set as a straight groove, and the extension direction of the gas guide groove is consistent with the extension direction of the corresponding tooth groove. There are no bends between the gas guide groove and the tooth groove, the gas guide stroke is short, the resistance is low, which is conducive to the discharge of hot gas flow and residue and can improve the welding quality.

[0026] In addition, there can be multiple air guide grooves. These grooves are evenly spaced around the axis of the connecting shaft segment. Each air guide groove is connected to a corresponding tooth groove. The cooperation of multiple air guide grooves ensures uniform and sufficient air delivery, which helps to ensure the consistency of the welding quality of the entire circle and improves the load-bearing performance.

[0027] In an optional embodiment, the air guide groove is spaced apart from the end face of the connecting shaft segment away from the gear body.

[0028] Based on the above solution, solder is prevented from entering the gas guide channel, making it less likely to clog the gas guide channel and less likely to affect the welding quality.

[0029] In an optional embodiment, an annular guide groove is provided on the outer peripheral surface of the connecting shaft segment. The annular guide groove is located on the side of the air guide groove away from the gear body and communicates with the air guide groove. The annular guide groove is spaced from the end face of the connecting shaft segment away from the gear body.

[0030] Based on the above scheme, the hot gas flow and residue generated during the welding process can be guided into the gas guide groove from different directions through the annular guide groove, resulting in good gas guiding effect.

[0031] Secondly, this utility model provides a gearbox, the gearbox comprising:

[0032] The double-tooth structure described in any of the foregoing embodiments.

[0033] The beneficial effects of this utility model embodiment include, for example:

[0034] In summary, the double-tooth structure provided in this embodiment, by setting multiple first grooves and multiple second grooves on the first and second sides of the first planetary gear, and having these grooves alternately arranged in the circumferential direction of the first planetary gear, forms an alternating, evenly distributed support structure along the circumferential direction of the first planetary gear's spokes. Simultaneously, the distance between the first and second sides gradually decreases from the center of the first planetary gear outwards, creating a gradually reinforced bending structure at the root of the first planetary gear along the axial direction. This achieves weight reduction while significantly increasing structural stiffness, increasing the natural frequency, changing the mode shape, and optimizing noise reduction. When the connecting shaft of the second planetary gear is inserted into the mounting hole, the gear body of the second planetary gear can contact the first or second side, forming axial positioning and bearing axial load. After the connecting shaft and the first planetary gear are welded, the torsional shear stress, bending stress, and axial shear stress at the weld location can be significantly reduced, significantly improving the static strength and fatigue life of the weld area. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the double-tooth structure from a first-view perspective in this embodiment;

[0037] Figure 2 This is a schematic diagram of the double-tooth structure in this embodiment from a second perspective;

[0038] Figure 3 This is a cross-sectional schematic diagram of the double-tooth structure in this embodiment;

[0039] Figure 4 This is a schematic diagram of the first planetary gear in this embodiment;

[0040] Figure 5 This is a cross-sectional schematic diagram of the first planetary gear in this embodiment;

[0041] Figure 6 This is a schematic diagram of the second planetary gear in this embodiment;

[0042] Figure 7This is a schematic diagram of the gearbox in this embodiment;

[0043] Figure 8 for Figure 7 A magnified schematic diagram of a portion of the image.

[0044] icon:

[0045] 100-First planetary gear; 101-Assembly hole; 102-First side surface; 103-Second side surface; 110-First groove; 120-Second groove; 130-First oil guide hole; 140-Second oil guide hole; 200-Second planetary gear; 201-Mounting hole; 210-Connecting shaft section; 211-Chamfer; 212-Air guide groove; 213-Annular guide groove; 220-Gear body; 221-Helical tooth; 222-Gear groove; 001-Gear housing; 002-Drive shaft; 003-Sun gear; 004-Gear ring; 005-Planet carrier. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0047] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0048] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0049] In the description of this utility model, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used 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 in which the product is usually placed during use, they are only for the convenience of describing this utility model 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 utility model.

[0050] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0051] It should be noted that, where there is no conflict, the features in the embodiments of this utility model can be combined with each other.

[0052] Please refer to Figures 1-6 This embodiment provides a double-tooth structure, including:

[0053] A first planetary gear 100 and a second planetary gear 200 are provided. The first planetary gear 100 is provided with a mounting hole 101 and has a first side surface 102 and a second side surface 103 that are axially opposite to each other in the mounting hole 101. A plurality of first grooves 110 are provided on the first side surface 102 and a plurality of second grooves 120 are provided on the second side surface 103. The plurality of first grooves 110 and the plurality of second grooves 120 are arranged alternately in the circumferential direction of the first planetary gear 100. The distance between the first side surface 102 and the second side surface 103 gradually decreases from the center of the first planetary gear 100 to the periphery.

[0054] The second planetary gear 200 includes an integral connecting shaft section 210 and a gear body 220. The connecting shaft section 210 and the gear body 220 are coaxially arranged. The outer diameter of the connecting shaft section 210 is smaller than the tooth tip circle diameter of the gear body 220. The connecting shaft section 210 is inserted and fixed in the mounting hole 101. The side of the gear body 220 contacts the first side 102 or the second side 103.

[0055] As described above, the assembly method of the double-tooth structure provided in this embodiment is as follows:

[0056] One end of the connecting shaft section 210 of the second planetary gear 200 is inserted into the mounting hole 101 of the first planetary gear 100. The first planetary gear 100 and the second planetary gear 200 are interference-fitted, and the end of the connecting shaft section 210 is approximately flush with either the first side 102 or the second side 103 of the first planetary gear 100. For example, when the connecting shaft section 210 is inserted from the first side 102, the end face of the connecting shaft section 210 is approximately flush with the second side 103, and one side of the gear body 220 of the second planetary gear 200 contacts the first side 102, achieving axial positioning. Similarly, when the connecting shaft section 210 is inserted from the second side 103, the end face of the connecting shaft section 210 is approximately flush with the first side 102, and one side of the gear body 220 of the second planetary gear 200 contacts the second side 103, achieving axial positioning. Then, at the end of the connecting shaft section 210 exposed to the first planetary gear 100, the connecting shaft section 210 and the first planetary gear 100 are welded and fixed. Since multiple first grooves 110 and multiple second grooves 120 are respectively provided on the first side 102 and the second side 103 of the first planetary gear 100, the multiple first grooves 110 and multiple second grooves 120 are arranged alternately in the circumferential direction of the first planetary gear 100. That is, the spokes of the first planetary gear 100 form an alternating concave-convex support structure along the circumferential direction. At the same time, the distance between the first side 102 and the second side 103 gradually decreases from the center of the first planetary gear 100 to the periphery, so that the first planetary gear 100 forms a bending-resistant structure with gradually strengthened roots along the axial direction, thereby achieving weight reduction while significantly improving structural stiffness, increasing natural frequency, changing mode shape, and optimizing noise reduction. When the connecting shaft section 210 of the second planetary gear 200 is inserted into the mounting hole 101, the gear body 220 of the second planetary gear 200 can contact the first side 102 or the second side 103 to form axial positioning and bear axial load. When the connecting shaft section 210 and the first planetary gear 100 are welded, the torsional shear stress, bending stress and axial shear stress borne by the weld position can be greatly reduced, and the static strength and fatigue life of the weld area can be significantly improved.

[0057] The following embodiments illustrate the details of the double-tooth structure of this application by way of example.

[0058] Please refer to Figures 1-6 In this embodiment, optionally, the double-gear structure includes a first planetary gear 100 and a second planetary gear 200. The first planetary gear 100 and the second planetary gear 200 are welded and fixed together and are coaxially arranged. The outer diameter of the first planetary gear 100 is larger than the outer diameter of the second planetary gear 200. That is, the first planetary gear 100 is a large gear relative to the second planetary gear 200, and the second planetary gear 200 is a small gear relative to the first planetary gear 100.

[0059] Optionally, the first planetary gear 100 is provided with a mounting hole 101. The cross-sectional profile of the mounting hole 101 can be circular. The mounting hole 101 is coaxially arranged with the first planetary gear 100, and its cross-section is a plane perpendicular to the axis of the mounting hole 101. For example, in this embodiment, the mounting hole 101 includes a variable-diameter section and a constant-diameter section that are connected. The end of the variable-diameter section away from the constant-diameter section is located on a first side surface 102, and the end of the constant-diameter section away from the variable-diameter section is located on a second side surface 103. The diameter of the variable-diameter section gradually decreases in the direction from the first side surface 102 to the second side surface 103. The first planetary gear 100 has a first side surface 102 and a second side surface 103 that are axially opposite to each other in the mounting hole 101. The distance between the first side 102 and the second side 103 gradually decreases from the center of the first planetary gear 100 outwards. For example, in this embodiment, the first side 102 is perpendicular to the axis of the first planetary gear 100, and the second side 103 protrudes outwards away from the first side 102. The distance between the first side 102 and the second side 103 gradually decreases from the center of the first planetary gear 100 outwards. That is, the second side 103 protrudes a greater distance closer to the axis and gradually decreases further away from the axis, forming a gradually convex structure. Because the second side 103 protrudes outwards, the length of the mounting hole 101 can be increased, thereby increasing the contact area between the second planetary gear 200 and the first planetary gear 100 and improving structural strength.

[0060] Meanwhile, a plurality of first grooves 110 are provided on the first side surface 102. For example, in this embodiment, the number of first grooves 110 can be six, and the plurality of first grooves 110 are evenly spaced in the circumferential direction of the mounting hole 101. A first oil guide hole 130 is provided on the bottom wall of each first groove 110, and part of the hole wall of the first oil guide hole 130 overlaps with the groove side wall of the first groove 110 away from the axis of the first planetary gear 100. It should be understood that the number of first oil guide holes 130 in each first groove 110 is not limited to one. Since the first oil guide hole 130 is located on the groove side wall of the first groove 110 away from the axis of the mounting hole 101, when the first planetary gear 100 rotates around its own axis, under the action of centrifugal force, the lubricating oil is concentrated at the position away from the groove side wall of the first planetary gear 100, which facilitates the discharge of the lubricating oil from the oil guide hole at this position, making the flow of lubricating oil smoother and the lubrication effect better.

[0061] Correspondingly, a plurality of second grooves 120 are provided on the second side surface 103. For example, in this embodiment, the number of second grooves 120 can be six, and the plurality of second grooves 120 are evenly spaced in the circumferential direction of the mounting hole 101. A second oil guide hole 140 is provided on the bottom wall of each second groove 120, and part of the hole wall of the second oil guide hole 140 overlaps with the groove side wall of the second groove 120 away from the axis of the second planetary gear 200. It should be understood that the number of second oil guide holes 140 in each second groove 120 is not limited to one. Since the second oil guide hole 140 is located on the groove side wall of the second groove 120 away from the axis of the mounting hole 101, when the second planetary gear 200 rotates around its own axis, under the action of centrifugal force, the lubricating oil is concentrated at the position away from the groove side wall of the second planetary gear 200, which facilitates the discharge of the lubricating oil from the oil guide hole at this position, making the flow of lubricating oil smoother and the lubrication effect better.

[0062] Furthermore, multiple first grooves 110 and multiple second grooves 120 are arranged alternately in the circumferential direction of the mounting hole 101. That is, in the circumferential direction of the mounting hole 101, there is a second groove 120 between any two adjacent first grooves 110, and similarly, there is a first groove 110 between any two adjacent second grooves 120. In this way, the spokes of the first planetary gear 100 form an alternating concave-convex support structure, which achieves weight reduction while significantly improving structural stiffness, increasing natural frequency, changing mode shape, and optimizing noise reduction.

[0063] Please refer to Figures 1-6In this embodiment, optionally, the second planetary gear 200 includes an integral connecting shaft section 210 and a gear body 220. The connecting shaft section 210 is located on one side of the gear body 220 and is coaxially arranged with the gear body 220. The outer diameter of the connecting shaft section 210 is smaller than the addendum circle diameter of the gear body 220. A chamfer 211 is provided at the end of the connecting shaft section 210 away from the gear body 220. The chamfer 211 can be a rounded corner. An air guide groove 212 and an annular guide groove 213 are provided on the outer circumferential surface of the connecting shaft section 210. There can be multiple air guide grooves 212, each of which can extend in a straight line. The multiple air guide grooves 212 are evenly spaced around the axis of the connecting shaft section 210. The number of air guide grooves 212 is designed as needed and is not specifically limited in this embodiment. In this embodiment, the length direction of the air guide groove 212 forms an angle with the axis of the connecting shaft section 210, that is, the air guide groove 212 is inclined relative to the axis of the connecting shaft section 210, which facilitates smooth docking with the obliquely extending tooth groove 222 formed on the gear body 220. There is no bend at the docking position, which is beneficial for guiding airflow and residue. The annular guide groove 213 is arranged around the axis of the connecting shaft section 210. The annular guide groove 213 is located on the side of all air guide grooves 212 away from the gear body 220, and there is a gap between the annular guide groove 213 and the end of the connecting shaft section 210 away from the gear body 220. Furthermore, there is a gap between the annular guide groove 213 and the chamfer 211. The end of all air guide grooves 212 away from the gear body 220 is connected to the annular guide groove 213. The gear body 220 has multiple helical teeth 221, which are evenly spaced around the axis of the connecting shaft segment 210, and an oblique tooth groove 222 is formed between adjacent helical teeth 221. The end of each air guide groove 212 away from the annular guide groove 213 can communicate with a tooth groove 222.

[0064] Meanwhile, a mounting hole 201 is provided at one end of the connecting shaft section 210, and the mounting hole 201 penetrates the end face of the gear body 220 away from the connecting shaft section 210. The mounting hole 201 facilitates the assembly of the second planetary gear 200 onto the planet carrier 005.

[0065] During assembly, the connecting shaft section 210 is inserted into the assembly hole 101 from the second side 103 until one side of the gear body 220 contacts the second side 103. At this point, the end face of the connecting shaft section 210 and the first side 102 are basically in the same plane. Then, the connecting shaft section 210 and the first planetary gear 100 are welded and fixed at the chamfer 211 position of the connecting shaft section 210 and the variable diameter hole section of the first planetary gear 100. During the welding process, the generated hot airflow and residue can enter the air guide groove 212 from the annular guide groove 213 and then be discharged from the corresponding tooth groove 222. Since the air guide groove 212 extends in a straight line, its stroke is short and its resistance is low, which is conducive to the rapid discharge of the hot airflow and harmful impurities generated during welding, resulting in high welding quality. Furthermore, the annular guide groove and multiple air guide grooves 212 work together to achieve uniform and sufficient air guidance throughout the entire circumference of the connecting shaft section 210, which is beneficial to ensuring the consistency of the welding quality of the entire circle and improving the load-sharing performance.

[0066] The double-tooth structure provided in this embodiment, with the structural design of the first planetary gear 100, can reduce weight while improving structural stiffness, increasing natural frequency, changing mode shape, and optimizing noise reduction.

[0067] Please refer to Figures 7-8 This embodiment also provides a gearbox, which includes a gear housing 001, a drive shaft 002, a sun gear 003, a ring gear 004, a planet carrier 005, and a double-gear structure. The drive shaft 002 is rotatably mounted within the gear housing 001 via bearings and can be connected to a motor to achieve torque input. The sun gear 003 is fixedly connected to the drive shaft 002, and the ring gear 004 is fixed within the gear housing 001. The second planetary gear 200 of the double-gear structure is mounted on the planet carrier 005, which is rotatably connected to the gear housing 001. The first planetary gear 100 meshes with the sun gear 003, and the gear body 220 of the second planetary gear 200 meshes with the ring gear 004. During operation, lubricating oil can enter the first groove 110 and reach the right side region of the double-gear structure through the first oil guide hole 130, lubricating the ring gear 004 and other components. The lubricating oil can also enter the second groove 120 and enter the left side area of ​​the double tooth structure through the second oil guide hole 140 to lubricate the sun gear 003 and other components.

[0068] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A double-tooth structure, characterized in that, include: A first planetary gear (100) and a second planetary gear (200). The first planetary gear (100) is provided with a mounting hole (101). The first planetary gear (100) has a first side surface (102) and a second side surface (103) that are axially opposite to each other in the mounting hole (101). The first side surface (102) is provided with a plurality of first grooves (110), and the second side surface (103) is provided with a plurality of second grooves (120). The plurality of first grooves (110) and the plurality of second grooves (120) are arranged alternately in the circumferential direction of the first planetary gear (100). The distance between the first side surface (102) and the second side surface (103) gradually decreases from the center of the first planetary gear (100) to the periphery. The second planetary gear (200) includes an integral connecting shaft section (210) and a gear body (220). The connecting shaft section (210) is coaxially arranged with the gear body (220). The outer diameter of the connecting shaft section (210) is smaller than the tooth tip circle diameter of the gear body (220). The connecting shaft section (210) is inserted and fixed in the mounting hole (101). The side of the gear body (220) contacts the first side (102) or the second side (103).

2. The double-tooth structure according to claim 1, characterized in that: The first side (102) is perpendicular to the axis of the first planetary gear (100), and the second side (103) protrudes outward in a direction away from the first side (102) so that the distance between the first side (102) and the second side (103) gradually decreases from the center of the first planetary gear (100) to the surrounding area; The side of the gear body (220) contacts the second side (103).

3. The double-tooth structure according to claim 1, characterized in that: The first groove (110) has a first oil guide hole (130) on the bottom wall of the groove. Or / and, a second oil guide hole (140) is provided on the bottom wall of the second groove (120).

4. The double-tooth structure according to claim 3, characterized in that: A portion of the hole wall of the first oil guide hole (130) overlaps with the groove sidewall of the first groove (110) that is away from the axis of the first planetary gear (100); Or / and, a portion of the hole wall of the second oil guide hole (140) overlaps with the groove sidewall of the second groove (120) away from the axis of the first planetary gear (100).

5. The double-tooth structure according to claim 1, characterized in that: The assembly hole (101) includes a variable diameter hole section and a constant diameter hole section that are connected. The end of the variable diameter hole section away from the constant diameter hole section is located on the first side surface (102), and the end of the constant diameter hole section away from the variable diameter hole section is located on the second side surface (103). The diameter of the variable diameter hole section gradually decreases in the direction from the first side surface (102) to the second side surface (103).

6. The double-tooth structure according to claim 5, characterized in that: A chamfer (211) is provided on the end face of the connecting shaft section (210) away from the gear body (220), and the chamfer (211) cooperates with the variable diameter hole section to form a solder receiving groove.

7. The double-tooth structure according to any one of claims 1-6, characterized in that: An air guide groove (212) is provided on the outer peripheral surface of the connecting shaft section (210); The gear body (220) has a tooth groove (222) on its outer peripheral surface, and the air guide groove (212) is connected to the corresponding tooth groove (222).

8. The double-tooth structure according to claim 7, characterized in that: The air guide groove (212) has a gap with the end face of the connecting shaft section (210) away from the gear body (220).

9. The double-tooth structure according to claim 7, characterized in that: An annular guide groove (213) is provided on the outer peripheral surface of the connecting shaft section (210). The annular guide groove (213) is located on the side of the air guide groove (212) away from the gear body (220). The annular guide groove (213) is connected to the air guide groove (212). The annular guide groove (213) is spaced from the end face of the connecting shaft section (210) away from the gear body (220).

10. A gearbox, characterized in that, The gearbox includes: The double-tooth structure according to any one of claims 1-9.

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