Spline shaft and mold for manufacturing the same

Abstract

This utility model provides a splined shaft and a mold for manufacturing it, including a cylindrical spindle body, a limiting tooth formed at one end of the spindle body for axial positioning, and a splined tooth formed at the other end of the spindle body for transmitting torque. The limiting tooth includes a main body connected to the spindle body, and a transition ring and a positioning ring for positioning the assembly components are sequentially formed at the end of the main body near the spindle body. The spindle body, the limiting tooth, and the splined tooth are integrally formed. By manufacturing the spindle body, the limiting tooth, and the splined tooth as a whole, the structural strength and coaxiality accuracy of the product are significantly improved. It avoids the assembly gap problem of traditional split designs, simplifies the assembly process, and ensures the positional accuracy between the limiting tooth and the splined tooth.

Description

Technical Field

[0001] This utility model relates to the field of cold heading forming technology for shaft parts, and in particular to a spline shaft and a mold for manufacturing it. Background Technology

[0002] As a core transmission component in mechanical transmission systems, the spline shaft's structural design directly affects transmission accuracy and assembly reliability. Traditional spline shafts suffer from the following technical problems in practical applications: First, the shaft end limiting structure is typically a split design, using circlips or nuts for axial positioning. This structure not only increases the number of parts and assembly steps but also easily leads to loosening during long-term use, affecting positioning accuracy. Second, the spline teeth and limiting structure are manufactured separately and then assembled, making it difficult to guarantee coaxiality, which can easily cause vibration and uneven loading during high-speed operation. Third, the lack of a transition structure at the connection between the limiting teeth and the main shaft body results in significant stress concentration, reducing fatigue life. While some existing spline shafts utilize a one-piece molding process, their limiting tooth structure is simple, consisting of only a single ring platform, which cannot simultaneously meet the dual requirements of precise positioning and stress transition. Especially under heavy-load conditions, this simple structure is prone to cracking at the root of the limiting teeth, severely impacting the reliability of the transmission system.

[0003] Therefore, there is an urgent need to develop a new type of integrated spline shaft. By optimizing the design of the limiting tooth structure, the stress distribution can be improved while ensuring axial positioning accuracy, thereby increasing the overall service life. Utility Model Content

[0004] The purpose of this invention is to provide a splined shaft and a mold for manufacturing it. Employing an integrated molding design, by manufacturing the main shaft body, limiting teeth, and splined teeth as a single unit, the structural strength and coaxiality accuracy of the product are significantly improved. This avoids the assembly gap problems of traditional split designs, simplifies the assembly process, and ensures the positional accuracy between the limiting teeth and the splined teeth.

[0005] To achieve the above objectives, the technical solution of this utility model is implemented as follows:

[0006] This utility model provides a spline shaft for transmitting torque to an assembled component. It includes a cylindrical spindle body, a limiting tooth formed at one end of the spindle body for axial positioning, and a spline tooth formed at the other end of the spindle body for transmitting torque. The limiting tooth includes a main body portion connected to the spindle body. A transition ring platform and a positioning ring platform for positioning the installation position of the assembled component are sequentially formed at one end of the main body portion near the spindle body. The spindle body, the limiting tooth, and the spline tooth are integrally formed.

[0007] Furthermore, the spline teeth include a guide structure formed on the spindle body to enhance the connection stability with the assembly component.

[0008] Furthermore, the guide structure includes a tooth end guide portion disposed along the axial direction of the main shaft for guiding the assembly component to align with the spline teeth when it is fitted in, and a tooth tip transition portion distributed circumferentially along the main shaft for reducing the contact stress between the spline teeth and the assembly component.

[0009] Furthermore, the positioning ring platform is a ring-shaped stepped structure, the transition ring platform is formed between the positioning ring platform and the main body, and the spline teeth are involute tooth structures.

[0010] Furthermore, the outer diameter of the transition ring platform is smaller than the outer diameter of the positioning ring platform, forming a stepped transition structure.

[0011] Furthermore, the outer surface of the main body of the limiting tooth is formed with a circumferentially distributed tooth-like structure.

[0012] A mold for manufacturing a spline shaft as described in any one of the embodiments of the present invention includes a first mold and a second mold for preforming the head of the spline shaft, a third mold for forming the head teeth, and a fourth mold for forming the shank splines, arranged sequentially. The fourth mold has a core for forming the spline teeth, and the inner sidewall of the core has a tooth-shaped structure adapted to the spline teeth.

[0013] Furthermore, the toothed structure includes a guide structure forming part corresponding to the spline tooth, and the toothed structure is distributed along the axial direction of the mold core.

[0014] Furthermore, the third mold includes a cavity for forming the limiting tooth and a forming part adapted to the cavity, wherein the forming part cooperates with the cavity to form the forming space of the limiting tooth.

[0015] Furthermore, the mold also includes a shearing die for trimming the raw materials, the shearing die being mounted on the side of the first mold away from the second mold.

[0016] This utility model provides a splined shaft, comprising a cylindrical spindle body, a locating tooth formed at one end of the spindle body for axial positioning, and a splined tooth formed at the other end of the spindle body for torque transmission. The locating tooth includes a main body connected to the spindle body, and a transition ring and a positioning ring for positioning the assembly components are sequentially formed at the end of the main body near the spindle body. The spindle body, locating tooth, and splined tooth are integrally formed. By manufacturing the spindle body, locating tooth, and splined tooth as a single unit, the structural strength and coaxiality accuracy of the product are significantly improved. It avoids the assembly gap problems of traditional split designs, simplifies the assembly process, and ensures the positional accuracy between the locating tooth and the splined tooth. Attached Figure Description

[0017] 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.

[0018] Figure 1 This is a schematic diagram of the structure of a spline shaft provided in an embodiment of the present invention.

[0019] Figure 2 This utility model provides a method for manufacturing... Figure 1 The diagram shows the structure of the mold for the spline shaft.

[0020] Figure 3 for Figure 2 The diagram shows the structure of the fourth mold from another perspective.

[0021] In the diagram: 1. Main shaft; 2. Limiting tooth; 21. Main body; 22. Transition ring platform; 23. Positioning ring platform; 3. Spline tooth; 31. Tooth end guide; 32. Tooth top transition part; 4. First mold; 5. Second mold; 6. Third mold; 61. Forming part; 7. Fourth mold; 71. Mold core; 72. Tooth structure; 8. Shearing mold. Detailed Implementation

[0022] The specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some, not all, of the embodiments of this utility model. Based on the description of this utility model, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this utility model.

[0023] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," etc., 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. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0024] The terms “upper,” “lower,” “left,” “right,” “front,” “back,” “top,” “bottom,” “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 this utility model is in use. They are only for the convenience of description and simplification, 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. Therefore, they should not be construed as limitations on this utility model.

[0025] The terms “first,” “second,” “third,” etc., are used merely to distinguish elements with similar properties, not to indicate or imply relative importance or a specific order.

[0026] The terms “include,” “comprising,” or any other variation thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0027] like Figures 1 to 3 As shown, a preferred embodiment of the present invention provides a splined shaft, including a cylindrical main shaft body 1, a limiting tooth 2 for axial positioning formed at one end of the main shaft body 1, and a splined tooth 3 for transmitting torque formed at the other end of the main shaft body 1. The limiting tooth 2 includes a main body portion 21 connected to the main shaft body 1. A transition ring platform 22 and a positioning ring platform 23 for positioning the installation position of the assembly components are sequentially formed at one end of the main body portion 21 near the main shaft body 1. The main shaft body 1, the limiting tooth 2, and the splined tooth 3 are integrally formed.

[0028] In this embodiment, the main shaft 1 is cylindrical with a uniform outer diameter and axial length. The limiting teeth 2 and spline teeth 3 are formed at its two ends. The main shaft 1 is an intermediate support structure connecting the limiting teeth 2 and the spline teeth 3, providing radial support for the assembled components and ensuring the overall rigidity of the spline shaft during transmission.

[0029] The limiting tooth 2 is a cylindrical structure coaxial with the main shaft 1, comprising three parts: the main body 21, the transition ring platform 22, and the positioning ring platform 23. Its overall outer diameter is larger than that of the main shaft 1, forming a stepped protrusion. This structure axially limits the assembly components (such as gears and sleeves) to prevent them from moving axially along the main shaft 1 during operation. The main body 21 of the limiting tooth 2 is cylindrical with an outer diameter smaller than that of the transition ring platform 22. Its outer surface is directly machined with tooth-like structures. One end connects to the transition ring platform 22, and the other end is free. The transition ring platform 22 connects to the main body 21 of the limiting tooth 2 at one end and to the positioning ring platform 23 at the other end, eliminating abrupt dimensional changes between the limiting tooth 2 and the main shaft 1 and reducing stress concentration. The positioning ring platform 23 is a ring-shaped stepped structure installed at the connection between the transition ring platform 22 and the main shaft 1. The connection between the positioning ring platform 23 and the main shaft 1 has an optimized rounded transition, solving the defect of burrs at the spline shaft connection.

[0030] Spline teeth 3 are formed at the end of the main shaft 1 away from the limiting teeth 2, and are located at both ends of the main shaft 1 respectively with the limiting teeth 2. They are uniform tooth-shaped structures (such as open-line teeth or rectangular teeth) along the outer circumferential surface of the main shaft 1, with rounded corners at the tooth tip / root and an axial length greater than that of the limiting teeth 2.

[0031] Specifically, in this embodiment, the main shaft body 1, the main body 21 (with a toothed structure on the outer surface), the transition ring platform 22, the positioning ring platform 23, and the spline teeth 3 of the spline shaft are all integrally formed by cold forging. Taking advantage of the plastic deformation characteristics of metal at room temperature, axial pressure is applied to the rod-shaped blank through a special mold, so that the blank is forged into the contours of each structure in one step in the cavity, without the need for subsequent splicing or welding, which improves the overall torsional strength and fatigue life. At the same time, the mold ensures the dimensional accuracy of each structure, reduces the amount of machining, and has high material utilization and fast production efficiency.

[0032] In this embodiment, the spline tooth 3 includes a guide structure formed on the spindle body 1 to assist the assembly component in precise engagement with the spline tooth 3, reduce assembly resistance and contact stress, and improve connection stability. The guide structure includes a tooth end guide portion 31 arranged axially along the spindle body 1 and a tooth tip transition portion 32 distributed circumferentially along the spindle body 1. The inner spline of the assembly component (such as a spline sleeve) is aligned with the tooth end guide portion 31 of the spline tooth 3. The assembly component is advanced circumferentially along the spindle body 1. The tooth end guide portion 31 continuously guides the inner spline and the spline tooth 3 to gradually mesh, avoiding misalignment and jamming between teeth. At the same time, the tooth tip transition portion 32 of the spline tooth 3 contacts the tooth groove edge of the inner spline through a rounded corner structure, reducing frictional resistance and local extrusion stress.

[0033] A mold for manufacturing the spline shaft described in this embodiment includes a first mold 4 and a second mold 5 for preforming the head of the spline shaft, a third mold 6 for forming the head teeth, and a fourth mold 7 for forming the spline on the shaft. The fourth mold 7 is provided with a core 71 for forming the spline teeth 3. The inner sidewall of the core 71 is provided with a tooth-shaped structure 72 adapted to the spline teeth 3.

[0034] In this embodiment, the first mold 4 is used for preliminary upsetting of the rod-shaped blank, extruding one end of the blank into the prototype shape of the spline shaft head (forming the approximate outline of the main body 21, transition ring 22, and positioning ring 23), laying the foundation for subsequent fine forming. The second mold 5 is installed after the first mold 4 and is used for secondary upsetting of the head pre-formed by the first mold 4, refining the head structure and making the head shape closer to the final size. The third mold 6 is used for "tooth forming" of the head, extruding the blank through the tooth pattern of the cavity, so that the outer surface of the main body 21 of the limiting tooth 2 forms the required tooth structure. The fourth mold 7 is used for "spline forming" of the rod part of the spline shaft, extruding the blank to form the rod part of the main shaft 1 through the cooperation of the mold core 71 and the sleeve, and forming spline teeth 3 at the end of the rod part with the help of the tooth structure 72 of the mold core 71.

[0035] Specifically, the mold core 71 is detachably installed in the fourth mold 7. The inner side wall of the mold core 71 is provided with a tooth structure 72 that is adapted to the spline tooth 3. The blank is extruded by the tooth structure 72, so that the end of the rod forms a spline tooth 3 (including tooth end guide part 31 and tooth top transition part 32) that is complementary to the tooth groove, ensuring the tooth shape accuracy and dimensional consistency of the spline tooth 3.

[0036] The third mold 6 includes a cavity for forming the limiting tooth 2 and a forming part 61 adapted to the cavity. The forming part 61 cooperates with the cavity to form the forming space of the limiting tooth 2.

[0037] Specifically, the mold also includes a shearing die 8 for trimming the raw materials, which is installed on the side of the first mold 4 away from the second mold 5.

[0038] The specific operating procedure for manufacturing splined shafts using this mold is as follows:

[0039] 1. Raw material correction: Cut the rod-shaped raw material to a fixed length, trim the burrs and flatness at the ends to obtain the initial blank that meets the dimensional requirements.

[0040] 2. Head preforming: Pre-forging is performed on one end of the billet to initially form the outline of the head (main body 21, transition ring platform 22, positioning ring platform 23).

[0041] 3. Head Refinement and Shaping: Refine the head structure, accurately shape the curved surface of the transition ring platform 22 and the step size of the positioning ring platform 23, so that the head outline is close to the final shape.

[0042] 4. Head tooth forming: The tooth-like structure is extruded on the outer surface of the limiting tooth 2 by the cavity and the forming part 61 to complete the final head forming.

[0043] 5. Spline forming of rod section: The rod section of the extruded blank is formed into the main shaft 1. At the same time, with the help of the toothed structure 72 inside the mold core 71, spline teeth 3 and guide structure are formed at the end of the rod section.

[0044] 6. Finished product output: The overall structure is formed in one piece.

[0045] This utility model provides a splined shaft, comprising a cylindrical spindle body 1, a locating tooth 2 for axial positioning formed at one end of the spindle body 1, and a splined tooth 3 for torque transmission formed at the other end of the spindle body 1. The locating tooth 2 includes a main body portion 21 connected to the spindle body 1. A transition ring 22 and a positioning ring 23 for positioning the assembly components are sequentially formed at the end of the main body portion 21 near the spindle body 1. The spindle body, locating tooth 2, and splined tooth 3 are integrally formed. By manufacturing the spindle body 1, locating tooth 2, and splined tooth 3 as a single unit, the structural strength and coaxiality accuracy of the product are significantly improved. This avoids the assembly gap problems of traditional split designs, simplifies the assembly process, and ensures the positional accuracy between the locating tooth 2 and the splined tooth 3.

[0046] 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 splined shaft for transmitting torque to assembled components, characterized in that, The assembly includes a columnar spindle body (1), a limiting tooth (2) for axial positioning formed at one end of the spindle body (1), and a spline tooth (3) for transmitting torque formed at the other end of the spindle body (1). The limiting tooth (2) includes a main body (21) connected to the spindle body (1). A transition ring platform (22) and a positioning ring platform (23) for positioning the installation position of the assembly components are formed sequentially at one end of the main body (21) near the spindle body (1). The spindle body (1), the limiting tooth (2), and the spline tooth (3) are integrally formed.

2. The splined shaft according to claim 1, characterized in that, The spline teeth (3) include a guide structure formed on the spindle body (1) for enhancing the connection stability with the assembly components.

3. The splined shaft according to claim 2, characterized in that, The guide structure includes a tooth tip guide (31) arranged axially along the main shaft (1) for guiding the assembly component to align with the spline tooth (3) when it is fitted in, and a tooth tip transition portion (32) distributed circumferentially along the main shaft (1) for reducing the contact stress between the spline tooth (3) and the assembly component.

4. The splined shaft according to claim 1, characterized in that, The positioning ring platform (23) is a ring-shaped stepped structure, the transition ring platform (22) is formed between the positioning ring platform (23) and the main body (21), and the spline tooth (3) is an involute tooth structure.

5. The splined shaft according to claim 4, characterized in that, The outer diameter of the transition ring (22) is smaller than the outer diameter of the positioning ring (23), forming a stepped transition structure.

6. The splined shaft according to claim 5, characterized in that, The main body (21) of the limiting tooth (2) has a circumferentially distributed tooth-like structure on its outer surface.

7. A mold for manufacturing a splined shaft as described in any one of claims 1-6, characterized in that, The mold includes a first mold (4) and a second mold (5) for preforming the head of the spline shaft, a third mold (6) for forming the head teeth, and a fourth mold (7) for forming the spline on the shaft. The fourth mold (7) is provided with a core (71) for forming the spline teeth (3). The inner sidewall of the core (71) is provided with a tooth-shaped structure (72) that is adapted to the spline teeth (3).

8. The mold according to claim 7, characterized in that, The toothed structure (72) includes a guide structure forming part corresponding to the spline tooth (3), and the toothed structure (72) is distributed along the axial direction of the mold core (71).

9. The mold according to claim 7, characterized in that, The third mold (6) includes a cavity for forming the limiting tooth (2) and a forming part (61) adapted to the cavity. The forming part (61) cooperates with the cavity to form the forming space of the limiting tooth (2).

10. The mold according to claim 7, characterized in that, The mold also includes a shearing die (8) for trimming the raw materials, the shearing die (8) being mounted on the side of the first mold (4) away from the second mold (5).

Images