A spline-free welded three-pin frame structure and three-ball pin type constant velocity universal joint

Abstract

The utility model provides a kind of no spline welding type three-pin frame structure and three ball pin type constant velocity universal joint, belong to automobile parts technical field, for three ball pin type constant velocity universal joint, no spline welding type three-pin frame structure includes: handle three-pin frame, its one end is equipped with welding end face, the other end is equipped with three circumferential distribution's axle neck;Bearing assembly includes respectively the first bearing, second bearing and third bearing on each described axle neck are pressed into;The handle three-pin frame is fixedly connected with the intermediate shaft of constant velocity drive shaft by the welding end face, and the no spline welding type three-pin frame structure does not include the retaining ring for axial limit. The utility model is through simplifying structure, cancel retaining ring and spline processing, using friction welding and center hole weight reduction design, while ensuring transmission performance, significantly reduce manufacturing cost, assembly complexity and product weight.

Description

Technical Field

[0001] This utility model relates to the field of automotive parts technology, and more specifically, to a spline-free welded three-pin frame structure and a three-ball pin constant velocity universal joint. Background Technology

[0002] Constant velocity drive shafts are key components in automotive powertrain systems, widely used in passenger vehicles. They primarily transmit power from the transmission to the front wheels, or from the rear differential to the rear wheels. Among these, the three-ball-pin universal joint is one of the most commonly used joint types for constant velocity drive shafts, widely adopted due to its excellent constant velocity transmission performance and axial extension capability.

[0003] Currently, three-ball pin universal joints on the market typically connect the three-pin bracket to the intermediate shaft through an interference fit of internal and external splines combined with an axial retaining ring. While this structure has advantages such as strong torque transmission capability, high centering accuracy, and compact structure, it also has significant drawbacks: the spline machining accuracy requirements are extremely high, making manufacturing difficult and costly; the assembly process is complex and highly dependent on specialized equipment; and once assembled, disassembly is difficult, leading to a significant increase in maintenance costs.

[0004] Therefore, there is an urgent need for a spline-free welded three-pin frame structure and a three-ball pin constant velocity universal joint that can simplify the structure, reduce the difficulty of processing and assembly, facilitate maintenance, and take into account the lightweight, while ensuring transmission performance, so as to overcome the shortcomings in current practical applications. Utility Model Content

[0005] The purpose of this invention is to provide a spline-free welded three-pin frame structure and a three-ball pin constant velocity universal joint, aiming to solve the problems mentioned in the background art.

[0006] This utility model is implemented as follows: a spline-free welded three-pin frame structure for a three-ball pin constant velocity universal joint, comprising:

[0007] A three-pin bracket with a handle has a welded end face at one end and three circumferentially distributed journals at the other end.

[0008] The bearing assembly includes a first bearing, a second bearing, and a third bearing respectively press-fitted onto each of the journals;

[0009] The three-pin bracket with handle is fixedly connected to the intermediate shaft of the constant velocity drive shaft through the welded end face, and the spline-free welded three-pin bracket structure does not include a retaining ring for axial positioning.

[0010] Optionally, the three-pin holder with handle has an overall rotating structure; the three journals are evenly distributed at 120° along the circumference; the outer ring of the bearing assembly is used for sliding engagement with the petal groove in the three-ball pin housing.

[0011] Optionally, the welding end face is a flat annular end face perpendicular to the axis of the three-pin bracket with handle, and the welding end face is connected to the intermediate shaft by friction welding, and both sides of the welding interface are circular rotating structures.

[0012] Optionally, the three-pin holder with handle has a three-pin holder side center hole along its axial direction, which is used as a machining reference and to reduce the overall weight.

[0013] Optionally, the three-pin bracket with handle includes a connecting shaft, the welding end face and the journal are located at the two ends of the connecting shaft respectively; the connecting shaft has an intermediate shaft side center hole at one end near the welding end face, and the intermediate shaft side center hole cooperates with the three-pin bracket side center hole.

[0014] Another objective of this utility model is to provide a three-ball pin constant velocity universal joint, including the aforementioned spline-free welded three-pin frame structure and a three-ball pin housing; the three-ball pin housing is cylindrical in shape, and its inner cavity is provided with a ball track, the ball track including a circular groove in the middle and three petal grooves evenly distributed along the circumference, the bearing assembly is accommodated in the petal grooves and can slide along the axial direction.

[0015] Optionally, each of the petal grooves includes a first inner arc wall and a second inner arc wall located on both sides of the bearing assembly, and a clearance groove located on the side away from the circular groove, the clearance groove being used to provide clearance space for the journal.

[0016] Optionally, one end of the three-ball pin housing is provided with a connecting spline for connection to the differential interface.

[0017] The spline-free welded three-pin frame structure and the three-ball pin constant velocity universal joint provided by this utility model have the following beneficial effects:

[0018] By eliminating the retaining ring, adopting a simplified structure with a handle-type three-pin holder and bearing assembly, and replacing the traditional spline connection with friction welding, the number of parts and processing steps are significantly reduced, thus lowering manufacturing and assembly costs. At the same time, a center hole is set in the center of the handle-type three-pin holder, which effectively reduces the overall weight and saves materials. While ensuring transmission performance and reliability, it achieves a comprehensive technical effect of lightweight, high efficiency and low cost.

[0019] Other features and advantages of the present invention will become clear from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the present invention and, together with their description, serve to explain the principles of the present invention.

[0021] Figure 1 A three-dimensional structural diagram of the spline-free welded three-pin frame structure provided in this embodiment of the utility model;

[0022] Figure 2 for Figure 1 Front view structural diagram;

[0023] Figure 3 for Figure 2 Schematic diagram of the structure of the housing part of the three-ball pin;

[0024] Figure 4 for Figure 2 Schematic diagram of the cross-sectional structure along the AA direction.

[0025] In the diagram: 10-Three-ball pin housing, 101-Connecting spline, 11-Ball track, 12-Circular groove, 13-Petal groove, 131-First inner arc wall, 132-Second inner arc wall, 133-Gap groove, 21-Three-pin holder with handle, 211-Welding end face, 212-Intermediate shaft side center hole, 213-Connecting shaft, 214-Three-pin holder side center hole, 215-Junior journal, 22-Bearing assembly, 221-First bearing, 222-Second bearing, 223-Third bearing. Detailed Implementation

[0026] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0027] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model 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 utility model.

[0028] The following is a detailed description, with reference to the accompanying drawings, of a spline-free welded three-pin frame structure and a three-ball pin constant velocity universal joint according to an embodiment of the present invention.

[0029] like Figure 1-4As shown, an embodiment of this utility model provides a spline-free welded three-pin frame structure for a three-ball pin constant velocity universal joint, comprising:

[0030] The three-pin bracket 21 with handle has a welding end face 211 at one end and three circumferentially evenly distributed journals 215 at the other end.

[0031] The bearing assembly 22 includes a first bearing 221, a second bearing 222 and a third bearing 223 respectively press-fitted onto each of the journals 215;

[0032] The three-pin bracket 21 with handle is fixedly connected to the intermediate shaft of the constant velocity drive shaft through the welded end face 211, and the spline-free welded three-pin bracket structure does not include a retaining ring for axial positioning.

[0033] Furthermore, the three-pin bracket 21 with handle has an overall rotating structure and is integrally forged from high-strength alloy steel or carburized steel to ensure its structural strength and fatigue life under high torque conditions.

[0034] The three journals 215 are evenly distributed at 120° along the circumference. The outer surface of each journal 215 is precision ground to a surface roughness Ra≤0.8μm to ensure the interference fit accuracy with the inner ring of the bearing and the smoothness of rotation.

[0035] The bearing assembly 22 is preferably a needle roller bearing, whose outer ring is directly slidably engaged with the petal groove 13 in the three-ball pin housing 10 to achieve axial extension and retraction.

[0036] The welding end face 211 is a flat annular end face perpendicular to the axis of the three-pin bracket with handle 21. Its end face runout tolerance is controlled within 0.05mm to meet the requirements of parallelism and coaxiality of the friction welding mating surfaces.

[0037] Since the retaining ring and spline fit in the traditional structure are eliminated, the axial positioning of the bearing assembly 22 on the journal 215 in this embodiment relies entirely on the interference fit force after press fitting and the constraint of the housing on the outer ring of the bearing during the subsequent assembly of the universal joint assembly. This simplifies the structure while still reliably preventing axial movement of the bearing.

[0038] In this structure, axial force is primarily transmitted to the three-ball housing 10 through the contact between the bearing outer ring and the petal groove 13, rather than relying on the retaining ring. The interference fit between the bearing inner ring and the journal 215 provides sufficient axial restraint to ensure structural stability under extreme operating conditions.

[0039] In addition, the three-pin bracket with handle 21 can be provided with a central hole (such as the three-pin bracket side central hole 214 described later) through the axial direction, which not only reduces weight, but also facilitates uniform heat conduction during welding and reduces residual welding stress.

[0040] In one embodiment, the three-pin holder 21 with a handle has a three-pin holder side center hole 214 along its axial direction. The three-pin holder side center hole 214 serves as a machining datum and reduces overall weight. That is, the three-pin holder side center hole 214 not only serves as a machining datum to improve manufacturing accuracy, but also effectively reduces overall weight and material costs. Specifically, in high-precision turning, grinding, and other machining processes, the three-pin holder side center hole 214 provides an ideal positioning point, which helps to ensure the coaxiality and geometric tolerances between components, thereby improving the assembly accuracy and operational stability of the final product.

[0041] Furthermore, the handle-mounted three-pin bracket 21 includes a connecting shaft 213, with the welding end face 211 and journal 215 located at opposite ends of the connecting shaft 213. This design enables the handle-mounted three-pin bracket 21 to not only securely connect with the intermediate shaft but also effectively transmit torque and withstand radial loads. Specifically, the connecting shaft 213 has an intermediate shaft-side center hole 212 at one end near the welding end face 211. This intermediate shaft-side center hole 212 mates with the three-pin bracket-side center hole 214, further reducing the overall weight of the assembly and providing a better heat conduction path during friction welding, thus reducing deformation or residual stress caused by localized overheating.

[0042] The welded end face 211 is connected to the intermediate shaft via friction welding, and both sides of the weld interface are circular rotating structures. The advantage of friction welding technology is that it achieves a high-strength, high-quality connection without the use of additional filler material, while ensuring the concentricity and physical properties of both sides of the weld interface. Furthermore, since the high temperature and pressure during welding are limited to the welded area, the impact on surrounding materials is minimal, thus maintaining the overall mechanical properties of the three-pin bracket 21 with its handle unchanged. This connection method not only simplifies the manufacturing process and reduces the complex procedures required for traditional spline connections, but also improves production efficiency and yield, making maintenance and replacement easier and faster.

[0043] In summary, this embodiment, through optimized design of the handle-type three-pin bracket 21 and the application of friction welding technology, achieves the goal of significantly reducing production costs and weight while maintaining good mechanical properties, demonstrating innovation and practicality.

[0044] like Figure 1-4 As shown, one embodiment of the present invention also provides a three-ball pin constant velocity universal joint, including the aforementioned spline-free welded three-pin frame structure and a three-ball pin housing 10;

[0045] The three-ball pin housing 10 is cylindrical in shape and is made of carburized alloy steel or medium carbon alloy steel through forging, machining, and heat treatment, possessing high strength and good wear resistance. The inner cavity of the three-ball pin housing 10 is provided with a ball track 11 for accommodating the three-pin bracket assembly. The ball track 11 includes a central circular groove 12 and three circumferentially distributed petal grooves 13. The circular groove 12 accommodates the overall contour of the three-pin bracket, while each petal groove 13 corresponds to a bearing assembly 22, forming a sliding guide channel.

[0046] The bearing assembly 22 (preferably a needle roller bearing) is housed in the petal groove 13 and can slide axially in the petal groove 13 to adjust the length of the drive shaft, that is, to adapt to the change in the length of the drive shaft caused by suspension bounce during vehicle operation, and to realize the axial extension function.

[0047] In one embodiment, each petal groove 13 includes a first inner arc wall 131 and a second inner arc wall 132 located on both sides of the bearing assembly 22, and a clearance groove 133 located on the side away from the circular groove 12. The clearance groove 133 is used to provide clearance space for the journal 215. The depth and width of the clearance groove 133 should be at least greater than the radial projection dimension of the journal 215 at the maximum swing angle to avoid motion interference. Preferably, the width of the clearance groove 133 is 1.2 to 1.5 times the diameter of the journal 215, and the depth is 0.8 to 1.2 times the length of the journal 215.

[0048] The bearing assembly 22 can move axially within the petal groove 13, maintaining a small frictional force. Specifically, the cross-sectional profile of the petal groove 13 matches the outer ring of the bearing, and its two side walls are smooth arc-shaped surfaces (i.e., the first inner arc wall 131 and the second inner arc wall 132), effectively reducing sliding friction resistance. At the same time, a clearance groove 133 is provided at the end of the petal groove 13 away from the circular groove 12, providing necessary clearance space for the journal 215 of the handle-type three-pin bracket 21 under large-angle swing or extreme extension and contraction conditions, preventing motion interference.

[0049] In one embodiment, one end of the three-ball-pin housing 10 is provided with a connecting spline 101 (or internal spline) for connecting to the differential interface (such as docking with the differential output shaft or hub flange) to achieve power input; the other end is fitted with a dust cover through an opening or retaining ring structure to form a sealed cavity, preventing grease leakage and the intrusion of external contaminants. The entire universal joint is injected with special high-temperature grease after assembly to ensure low wear and high reliability during long-term operation.

[0050] By combining the spline-free welded three-pin frame structure with the optimized three-ball pin housing 10, this embodiment not only retains the constant velocity transmission characteristics and axial compensation capability of the traditional three-ball pin universal joint, but also significantly simplifies the connection structure on the three-pin frame side, avoiding high-precision spline machining and retaining ring assembly, thereby greatly reducing manufacturing costs and assembly complexity while ensuring performance.

[0051] like Figure 1-4 As shown, the assembly method for a spline-free welded three-pin frame structure includes the following steps:

[0052] S1: Press the first bearing 221, the second bearing 222, and the third bearing 223 onto the three journals 215 of the three-pin holder with handle 21 to form the bearing assembly 22. The pressing process is carried out using a hydraulic or servo press under controlled pressing force (usually 10–30 kN) and displacement accuracy (±0.1 mm) to ensure a stable interference fit between the bearing inner ring and the journal 215, thereby achieving reliable circumferential torque transmission and axial positioning.

[0053] S2: Align the welding end face 211 of the three-pin bracket with handle with the intermediate shaft of the constant speed drive shaft. Both of their mating end faces are circular rotating structures, and the coaxiality error is controlled within ≤0.05mm to meet the geometric matching requirements of subsequent friction welding.

[0054] S3: Using inertial friction welding or continuous drive friction welding, the welding end face 211 is fixed to the intermediate shaft. During the welding process, by setting appropriate rotation speed (1500–3000 rpm), upsetting pressure (80–200 MPa), and welding time, the interface metals achieve metallurgical bonding in a high-temperature plastic state, forming a high-strength, high-coaxiality integrated connection. After welding, flash removal, annealing, or shot peening can be performed to eliminate residual stress and improve fatigue performance.

[0055] The entire assembly process eliminates the need for axial retaining rings for positioning, as well as the need to machine internal splines, external splines, or spline grooves on the three-pin holder 21 or intermediate shaft, completely eliminating complex processes such as high-precision spline grinding, inspection, and specialized assembly tooling. Since the bearing assembly 22 already possesses sufficient axial stability after press-fitting, and the three-ball-pin housing 10 provides axial constraint to the bearing outer ring during assembly, reliable operation of the universal joint under all working conditions can be ensured even without the retaining rings.

[0056] This assembly method not only significantly shortens the process flow and reduces equipment investment and labor costs, but also improves product consistency and maintainability. When the universal joint fails, the three-pin bracket assembly can be quickly replaced by cutting the weld, without scrapping the entire drive shaft, which has good economic efficiency and sustainability.

[0057] The above embodiments of this utility model provide a spline-free welded three-pin frame structure and a three-ball pin constant velocity universal joint, which have the following advantages:

[0058] By eliminating the retaining ring used for axial positioning in the traditional structure, the three-pin holder structure consists only of a three-pin holder with a handle 21 and a bearing assembly 22, which significantly reduces the number of parts, simplifies the assembly process, reduces reliance on special assembly equipment, and improves production efficiency.

[0059] The handle-type three-pin bracket 21 is directly connected to the intermediate shaft by friction welding, which eliminates the complex machining process of high-precision internal splines, external splines and spline grooves in the traditional solution. This not only reduces the difficulty of machining and equipment investment, but also effectively controls the manufacturing cost.

[0060] A center hole 214 is provided on the side of the three-pin bracket 21 with a handle. This can serve as a machining reference to improve manufacturing accuracy, effectively reduce the overall weight and save raw materials, and meet the strength requirements while conforming to the development trend of lightweight automotive parts.

[0061] The bearing assembly 22 can slide smoothly axially within the petal groove 13 of the housing. Combined with the clearance groove 133's avoidance design of the journal 215, it ensures that the drive shaft maintains low friction and low wear during the extension and retraction adjustment process, thereby improving the durability and transmission smoothness of the universal joint.

[0062] In summary, this utility model achieves multiple technical advantages such as simplified structure, optimized cost, reduced weight, and convenient assembly while ensuring constant velocity transmission performance, and has good prospects for industrial application.

[0063] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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 based on the specific circumstances.

[0064] In this specification, the terms "embodiment," "example," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0065] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A spline-free welded three-pin frame structure for a three-ball pin constant velocity universal joint, characterized in that, include: The three-pin bracket with handle (21) has a welded end face (211) at one end and three circumferentially distributed journals (215) at the other end. The bearing assembly (22) includes a first bearing (221), a second bearing (222) and a third bearing (223) respectively press-fitted onto each of the journals (215). The handle-type three-pin bracket (21) is fixedly connected to the intermediate shaft of the constant velocity drive shaft through the welded end face (211), and the spline-free welded three-pin bracket structure does not include a retaining ring for axial positioning.

2. The spline-free welded three-pin frame structure according to claim 1, characterized in that, The three-pin bracket with handle (21) has a rotating structure as a whole; The three journals (215) are evenly distributed at 120° along the circumferential direction; The outer ring of the bearing assembly (22) is used for sliding engagement with the petal groove (13) inside the three-ball pin housing (10).

3. The spline-free welded three-pin frame structure according to claim 1, characterized in that, The welding end face (211) is a flat annular end face perpendicular to the axis of the three-pin bracket (21) with handle, and the welding end face (211) is connected to the intermediate shaft by friction welding, and both sides of the welding interface are circular rotating structures.

4. The spline-free welded three-pin frame structure according to claim 2, characterized in that, The three-pin holder (21) with handle has a three-pin holder side center hole (214) along its axial direction. The three-pin holder side center hole (214) is used as a machining reference and to reduce the overall weight.

5. The spline-free welded three-pin frame structure according to claim 4, characterized in that, The three-pin bracket (21) with handle includes a connecting shaft (213), and the welding end face (211) and the journal (215) are located at the two ends of the connecting shaft (213), respectively. The connecting shaft (213) has an intermediate shaft side center hole (212) at one end near the welding end face (211), and the intermediate shaft side center hole (212) is matched with the three pin frame side center hole (214).

6. A three-ball pin type constant velocity universal joint, characterized in that, Includes the spline-free welded three-pin frame structure as described in any one of claims 1-5, and the three-ball pin housing (10). The three-ball pin housing (10) is cylindrical in shape, and its inner cavity is provided with a ball track (11). The ball track (11) includes a circular groove (12) located in the middle and three petal grooves (13) evenly distributed along the circumference. The bearing assembly (22) is housed within the petal groove (13) and can slide axially.

7. The three-ball pin type constant velocity universal joint according to claim 6, characterized in that, Each of the petal grooves (13) includes a first inner arc wall (131) and a second inner arc wall (132) located on both sides of the bearing assembly (22), and a clearance groove (133) located on the side away from the circular groove (12), the clearance groove (133) being used to provide clearance space for the journal (215).

8. The three-ball pin type constant velocity universal joint according to claim 6, characterized in that, One end of the three-ball pin housing (10) is provided with a connecting spline (101) for connecting to the differential interface.

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