Sun gear shaft with double guide spline structure

Abstract

The utility model belongs to the transmission parts design technical field relates to a sun gear shaft with double guide spline structure. Sun gear shaft body, one end of sun gear shaft body is provided with sun gear tooth, the other end is provided with outer spline, the both sides tooth surface of every spline tooth on the assembly end of outer spline all is provided with guide angle. The guide angle is from the each tooth top circle arc line center of assembly end of outer spline as the starting point, extends to the tooth root by tooth top bevel, and the angle with tooth center surface is 10~15. Through setting up guide angle on the both sides tooth surface of every spline tooth of outer spline assembly end, the two -way guide structure is formed. When the initial contact of inner and outer spline, the tooth top is opposite or the tooth surface is misaligned and is contacted, the guide angle bevel can all automatically produce radial component force, drives the inner spline tooth along the bevel and slides into the tooth groove, eliminates the manual rotation adjustment link in the process of assembly, promotes the blind assembly success rate, saves the assembly time.

Description

Technical Field

[0001] This utility model belongs to the field of transmission component design technology, and relates to a sun gear shaft with a double-guided spline structure. Background Technology

[0002] In hydraulic automatic transmissions (AT), planetary mechanisms are widely used due to their compact structure and diverse output methods. However, this compact structure brings some assembly inconveniences, especially since multiple planetary sets are nested together and need to be connected to different shift clutch assemblies to achieve power input and output. This results in a very compact spatial arrangement and nested component design. For some mating parts with long, deep holes, the installation position cannot be adjusted visually during assembly.

[0003] For example, in an automatic transmission (AT), the sun gear shaft of the first planetary gear set is fitted between the second clutch hub and the oil distribution plate of the clutch assembly. The sun gear shaft provides power input through a relatively long external spline that engages with the internal spline of the oil distribution plate. During the assembly of the sun gear shaft and the oil distribution plate spline, the ends of the internal and external spline teeth often abut against each other, preventing direct insertion. It is necessary to rotate the sun gear shaft during assembly to adjust the angle, ensuring the internal and external splines form a tooth-to-groove relationship before the two parts can be smoothly assembled, causing significant inconvenience in the assembly process. Figure 1 , Figure 2 and Figure 3 As shown, the external spline teeth of a conventional sun gear shaft have circumferential chamfers to facilitate entry into the mating hole during assembly. However, these chamfers only serve as guides during shaft-hole installation and do not solve the problem of tooth-to-tooth contact during internal and external spline assembly. For example, the Chinese utility model patent CN 222363316 U, entitled "A Spline Mating Structure and Transmission," only addresses the risk of wear and fatigue caused by the gaps between splines under alternating loads, but does not solve the problem of convenient spline assembly in long, deep hole structures. Utility Model Content

[0004] The purpose of this invention is to solve the technical problem in the prior art where the internal and external splines collide during the blind assembly process of parts in hydraulic automatic transmissions, making it difficult to complete the assembly. The invention provides a sun gear shaft with a double-guided spline structure.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, this utility model discloses a sun gear shaft with a double-guided spline structure, including a sun gear shaft body, one end of which is provided with sun gear teeth and the other end with an external spline; each spline tooth on the assembly end of the external spline is provided with a guide angle on both sides of the tooth surface.

[0007] Further improvements are made in the following aspects:

[0008] The guide angle starts from the center of the arc of each tooth tip at the assembly end of the external spline, extends obliquely from the tooth tip to the tooth root, and forms an angle of 10~15˚ with the center surface of the tooth.

[0009] The axial length of the guide angle is 1.2 to 1.5 times the module of the external spline.

[0010] The guide angle forms a guide slope with an axial length of 3~5mm on both sides of the tooth surface of the external spline.

[0011] The surface roughness Ra of the guide angle is ≤3.2μm, and it smoothly transitions with the tooth surface of the external spline.

[0012] The guide angle and the root of the external spline are provided with a fillet with a radius of R0.2~0.5mm.

[0013] The symmetry tolerance of the guide angles on both sides of the tooth surfaces of each spline tooth on the assembly end of the external spline is ≤0.05mm.

[0014] The guide angle surface is covered with a diamond-like carbon coating with a thickness of 2~3μm and a friction coefficient ≤0.15.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] This utility model discloses a sun gear shaft with a double-guided spline structure. By simultaneously setting guide angles on both sides of the tooth surface of each spline tooth at the assembly end of the external spline, a bidirectional guiding structure is formed. When the internal and external splines initially contact, the tooth tips are opposite or the tooth surfaces are misaligned and abut against each other. The inclined surface of the guide angle can automatically generate a radial component force, driving the internal spline tooth to slide into the tooth groove along the inclined surface. This eliminates the manual rotation and adjustment step in the assembly process, improves the success rate of blind assembly, saves assembly time, and reduces the skill requirements for operators.

[0017] Furthermore, the guide angle forms an angle of 10 to 15° with the center plane of the tooth. If the angle is less than 10°, the strength of the guide angle end face will be insufficient. If the angle is greater than 15°, the guiding force will be insufficient. This solution achieves the optimal balance between guiding efficiency and structural strength. It establishes a proportional scaling relationship with the spline module to adapt to different specifications of splines and avoids insufficient guidance due to excessively short length or weakening of the tooth body due to excessively long length.

[0018] Furthermore, the guide angle forms guide ramps with an axial length of 3~5mm on both sides of the tooth surface of the external spline, covering the critical guide area and ensuring the guiding function with minimal material removal. The surface roughness Ra of the guide angle is ≤3.2μm, reducing assembly thrust. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying 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.

[0020] Figure 1 A schematic diagram of the assembly of the sun gear shaft with the clutch hub and oil distribution plate in the prior art;

[0021] Figure 2 This is a schematic diagram of the sun gear shaft and the chamfer at the end of its spline teeth in the prior art;

[0022] Figure 3 A schematic diagram of the oil distribution plate structure fitted to the sun gear shaft in the prior art;

[0023] Figure 4 This is a schematic diagram of a sun gear shaft with a double-guide spline structure in an embodiment of this utility model;

[0024] Figure 5 This is an enlarged view of the double-guide spline structure of a sun gear shaft with a double-guide spline structure according to an embodiment of the present invention.

[0025] Wherein: 1-Sun gear shaft body; 11-External spline; 111-Circumferential chamfer at the end of the spline tooth of the ordinary sun gear shaft; 112-Left tooth surface guide angle at the end of the spline tooth of the sun gear shaft; 113-Right tooth surface guide angle at the end of the spline tooth of the sun gear shaft; 12-Sun gear tooth; 2-Clutch distributor plate; 21-Internal spline of the distributor plate; 3-Clutch hub. Detailed Implementation

[0026] 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.

[0027] 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.

[0028] 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.

[0029] In the description of the embodiments of this utility model, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" 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 utility model product is in use, they are only for the convenience of describing the 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 on the utility model. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0030] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0031] In the description of the embodiments of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0032] The present invention will now be described in further detail with reference to the accompanying drawings:

[0033] See Figure 4 and Figure 5This utility model discloses a sun gear shaft with a double-guided spline structure, including a sun gear shaft body 1. One end of the sun gear shaft body 1 is provided with sun gear teeth 12, and the other end is provided with an external spline 11. Each spline tooth on the assembly end of the external spline 11 has guide angles on both sides of its tooth surface. The guide angles include a guide angle 112 on the left tooth surface of the sun gear shaft spline tooth end and a guide angle 113 on the right tooth surface of the sun gear shaft spline tooth end. The guide angles start from the center of the arc of each tooth tip at the assembly end of the external spline 11, extend obliquely from the tooth tip to the tooth root, and form an angle of 10 to 15° with the center plane of the tooth. If the angle is <10°, the end face strength of the guide angle will be insufficient; if the angle is >15°, the guiding force will be insufficient. This solution achieves the optimal balance between guiding efficiency and structural strength. The axial length of the guide angle is 1.2 to 1.5 times the module of the external spline 11, establishing a proportional scaling relationship with the spline module to adapt to splines of different specifications, avoiding insufficient guidance due to excessive shortness or weakening of the tooth body due to excessive length. Alternatively, the guide angle can form a guide slope with an axial length of 3 to 5 mm on both sides of the tooth surface of the external spline 11, covering the key guide area, and ensuring the guiding function with minimal material removal.

[0034] The surface roughness Ra of the guide angle is ≤3.2μm, ensuring a smooth transition with the tooth surface of the external spline 11 and reducing assembly thrust. A fillet with a radius R0.2~0.5mm is provided at the junction of the guide angle and the tooth root of the external spline 11. The symmetry tolerance of the guide angle on both sides of the tooth surface of each spline tooth on the assembly end of the external spline 11 is ≤0.05mm. The surface of the guide angle is covered with a diamond-like carbon coating with a thickness of 2~3μm and a friction coefficient ≤0.15. First, controlling the surface roughness to Ra≤3.2μm and forming a smooth transition with the tooth surface effectively reduces microscopic contact stress concentration, thereby reducing frictional resistance during assembly and preventing scratches on the mating surfaces, significantly improving assembly smoothness and reliability of repeated assembly and disassembly. The R0.2~0.5mm transition fillet at the tooth root optimizes stress flow distribution, eliminating stress concentration caused by traditional right-angle transitions, and improving the bending fatigue strength of the tooth root.

[0035] This utility model discloses a sun gear shaft with a double-guided spline structure. By simultaneously setting guide angles on both sides of the tooth surface of each spline tooth at the assembly end of the external spline, a bidirectional guiding structure is formed. When the internal and external splines initially contact, the tooth tips are opposite or the tooth surfaces are misaligned and abut against each other. The inclined surface of the guide angle can automatically generate a radial component force, driving the internal spline tooth to slide into the tooth groove along the inclined surface. This eliminates the manual rotation and adjustment step in the assembly process, improves the success rate of blind assembly, saves assembly time, and reduces the skill requirements for operators.

[0036] The working process of this utility model is as follows:

[0037] The sun gear shaft 1 is mounted between the clutch hub 3 and the clutch distributor plate 2. The sun gear shaft 1 consists of two parts: the sun gear teeth 12 and the sun gear shaft spline 11. The sun gear shaft provides power input by engaging with the internal spline 21 of the clutch distributor plate through its external spline 11. During assembly, when the guide angles 112 and 113 on both sides of the tooth tip of the external spline 11 of the sun gear shaft contact the tooth tip of the internal spline 21 of the distributor plate, they automatically guide the teeth of the external spline 11 of the sun gear shaft into the tooth groove of the internal spline 21 of the distributor plate, achieving smooth assembly during blind assembly. This effectively solves the problem of teeth abutting and failing to assemble properly in spline assembly of deep-hole parts with nested structures in AT transmissions.

[0038] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A sun gear shaft with a double-guided spline structure, characterized in that, It includes a sun gear shaft body (1), one end of which is provided with a sun gear tooth (12), and the other end is provided with an external spline (11); the two sides of each spline tooth on the assembly end of the external spline (11) are provided with guide angles.

2. The sun gear shaft with a double-guided spline structure according to claim 1, characterized in that, The guide angle starts from the center of the arc of each tooth tip at the assembly end of the external spline (11), extends obliquely from the tooth tip to the tooth root, and forms an angle of 10~15˚ with the tooth center surface.

3. The sun gear shaft with a double-guided spline structure according to claim 2, characterized in that, The axial length of the guide angle is 1.2 to 1.5 times the module of the external spline (11).

4. The sun gear shaft with a double-guided spline structure according to claim 2, characterized in that, The guide angle forms a guide slope with an axial length of 3~5mm on both sides of the tooth surface of the external spline (11).

5. The sun gear shaft with a double-guided spline structure according to claim 1, characterized in that, The surface roughness Ra of the guide angle is ≤3.2μm, and it smoothly transitions with the tooth surface of the external spline (11).

6. The sun gear shaft with a double-guided spline structure according to claim 1, characterized in that, The guide angle and the tooth root of the external spline (11) are provided with a rounded corner with a radius of R0.2~0.5mm.

7. The sun gear shaft with a double-guided spline structure according to claim 1, characterized in that, The symmetry tolerance of the guide angle of the two sides of each spline tooth on the assembly end of the external spline (11) is ≤0.05mm.

8. The sun gear shaft with a double-guided spline structure according to claim 1, characterized in that, The guide angle surface is covered with a diamond-like carbon coating with a thickness of 2~3μm and a friction coefficient ≤0.15.

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