A steel ball type constant velocity joint

Abstract

The utility model discloses a steel ball type constant velocity universal joint relates to automobile transmission system technical field, including outer star wheel, inner star wheel, retainer and steel ball. The ball channel is established on outer star wheel and inner star wheel, and inner star wheel is coaxially arranged in outer star wheel, and retainer is located between the two, and the window hole of unequal length is established thereon, and the window hole, ball channel and steel ball number are equal, outer star wheel ball channel opening side has the lead -in structure, and the edge of spherical surface opening has the avoidance structure. The lead -in structure is spherical surface, and the radius is greater than or equal to steel ball radius, and steel ball is guided to slide into ball channel, and the assembly radial pressure force is reduced, and the inner star wheel swing angle is reduced. The avoidance structure is at least four symmetrical distribution, and along the opening side to the interface side cutting, under the premise that not increasing the outer star wheel spherical surface opening diameter, ensure that retainer is smoothly loaded. The utility model has significantly enhanced the retainer strength, realized the miniaturization and light weight.

Description

Technical Field

[0001] This utility model relates to the field of automotive transmission system technology, specifically a steel ball constant velocity universal joint. Background Technology

[0002] The constant velocity joint (CV joint) is a key component of automotive transmission systems, used to transmit torque between the drive axle and the wheels and to accommodate large-angle swaying during vehicle steering. With the automotive industry, especially electric vehicles, increasingly demanding lightweight, high-efficiency, and compact designs, how to reduce the size and weight of the CV joint while maintaining its structural strength under large sway angles and high torque conditions has become an important research direction in this field.

[0003] To achieve miniaturization of constant velocity universal joints, a common technical solution is to upgrade the traditional six-ball structure to an eight-ball structure. By increasing the number of balls, the diameter and stress on each ball can be reduced, theoretically allowing for a smaller overall size of the universal joint. However, this design also introduces new technical challenges: to accommodate more balls, more openings need to be made in the cage, resulting in a narrower intermediate beam between the openings. During large swing angle operations, the cage bears enormous stress, and the narrowed intermediate beam makes it a weak point in the entire assembly; its insufficient strength limits the potential for miniaturization.

[0004] Therefore, there is an urgent need for a steel ball type constant velocity universal joint to solve the above problems. Utility Model Content

[0005] The purpose of this utility model embodiment is to provide a steel ball constant velocity universal joint to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A steel ball constant velocity universal joint includes: an outer star wheel, an inner star wheel, a cage, and a plurality of steel balls. Both the outer and inner star wheels have tracks for the steel balls to roll. The inner star wheel is located inside the outer star wheel and is coaxially arranged. The cage is located between the outer and inner star wheels. The cage has a plurality of sets of openings, including short and long openings of different lengths. The number of openings, tracks, and steel balls is equal. Each track on the outer star wheel has an inlet structure on its opening side, and an avoidance structure is provided at the edge of the spherical opening of the outer star wheel.

[0008] As a further embodiment of this utility model: the short window and the long window are spaced apart along the circumference of the retainer.

[0009] As a further embodiment of this utility model: the shape of the inlet structure is a spherical curved surface, the radius of which is greater than or equal to the radius of the steel ball.

[0010] As a further embodiment of this utility model: the avoidance structure is symmetrically arranged, and at least four of them are symmetrically distributed along the edge of the spherical opening of the outer star wheel.

[0011] Compared with the prior art, the beneficial effects of this utility model are:

[0012] 1. Significantly enhanced cage strength, achieving deep miniaturization and lightweighting: This application breaks through the traditional constraints between "strength" and "assembly" by coordinating the design of the cage with long and short windows, the guide structure of the outer star wheel track, and the avoidance structure of the outer star wheel opening. Among them, the spherical guide structure reduces the swing angle of the inner star wheel required for steel ball assembly, creating conditions for further shortening the length of the cage window. Combined with the layout of long and short windows, it greatly increases the effective cross-section of the intermediate beam between the cage windows, significantly improving the torsional strength and fatigue life of the cage. Based on this strength margin, the key dimensions such as the pitch circle diameter and inner and outer diameter of the cage and inner and outer star wheels can be reduced while meeting the same performance requirements, thereby achieving further miniaturization and lightweighting of the entire universal joint assembly based on the existing technology.

[0013] 2. Ensuring excellent assemblability and reducing manufacturing costs: The elongated window design of this invention ensures the feasibility of steel ball assembly, while the avoidance structure of the outer wheel opening cleverly solves the assembly interference problem of the reinforced cage itself. While pursuing ultimate performance, this invention comprehensively considers the assembly needs of each stage in industrial production, avoiding process complexity or decreased yield caused by structural optimization.

[0014] 3. Improved overall performance to meet higher technical requirements: Through the above structural optimization, the constant velocity universal joint of this utility model can withstand the harsh working conditions of large swing angle and large torque in a smaller space size and lighter weight, better meeting the higher performance requirements of modern automobiles for transmission systems, such as high efficiency, lightweight, and small turning radius. Attached Figure Description

[0015] Figure 1 This is a front structural diagram of a steel ball constant velocity universal joint according to an embodiment of the present utility model.

[0016] Figure 2 for Figure 1 Cross-sectional view of AA.

[0017] Figure 3 This is a schematic diagram of the imported structure in an embodiment of this utility model.

[0018] Figure 4This is a schematic diagram of the cage in the installation state in an embodiment of this utility model.

[0019] Figure 5 for Figure 4 Cross-sectional view of BB in the middle.

[0020] Figure 6 for Figure 5 A magnified schematic diagram of the structure at point A in the middle.

[0021] Figure 7 This is a schematic diagram of the cage structure in an embodiment of the present invention.

[0022] Figure 8 This is a schematic diagram of the structure of the cage and steel ball in an embodiment of this utility model.

[0023] Figure 9 This is a schematic diagram of the front structure of the outer star wheel in an embodiment of this utility model.

[0024] Figure 10 for Figure 9 Enlarged schematic diagram of the structure at point B.

[0025] In the diagram: 1. Outer star wheel; 2. Inner star wheel; 3. Cage; 4. Steel ball; 5. Guide structure; 6. Window; 61. Short window; 62. Long window; 7. Avoidance structure. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0027] In this embodiment of the utility model, please refer to Figures 1 to 10 A steel ball constant velocity universal joint includes: an outer star wheel 1, an inner star wheel 2, a cage 3, and a plurality of steel balls 4. The outer star wheel 1 and the inner star wheel 2 are provided with ball tracks for the steel balls 4 to roll. The inner star wheel 2 is located inside the outer star wheel 1 and is coaxially arranged. The cage 3 is located between the outer star wheel 1 and the inner star wheel 2. The cage 3 is provided with a plurality of sets of windows 6. The plurality of sets of windows 6 include short windows 61 and long windows 62 of different lengths. The plurality of sets of windows 6, ball tracks, and steel balls 4 are equal in number. Each ball track of the outer star wheel 1 is provided with an inlet structure 5 on the opening side. The outer star wheel 1 is provided with an avoidance structure 7 at the edge of the spherical opening.

[0028] In the assembled state, the retainer 3 is housed in the internal cavity of the outer star wheel 1, the inner star wheel 2 is housed inside the retainer 3, and a plurality of steel balls 4 are respectively placed in the window holes 6 opened on the retainer 3. The steel balls 4 are in contact with the ball tracks opened on the inner wall of the outer star wheel 1 and the ball tracks opened on the outer surface of the inner star wheel 2, serving as a medium for transmitting torque.

[0029] As one embodiment of this utility model, the outer star wheel 1, inner star wheel 2, cage 3 and steel ball 4 are made of high-strength alloy steel to ensure that the universal joint has sufficient strength and wear resistance when subjected to high torque and impact loads.

[0030] In this embodiment, the number of window holes 6 can be six, eight, or ten, preferably eight.

[0031] As one embodiment of this utility model, please refer to Figures 1 to 8 The retainer 3 has eight windows 6 evenly spaced along its circumference to accommodate eight steel balls 4. In this embodiment, the eight windows 6 are designed with two different lengths: four short windows 61 and four long windows 62. The long windows 62 have a longer length L4, and the short windows 61 have a shorter length L3. The four short windows 61 and four long windows 62 are alternately spaced along the circumference of the retainer 3, meaning that each short window 61 is adjacent to a long window 62 on both sides, and vice versa.

[0032] It should be noted that this design of long and short window openings has significant technical advantages. The shorter window opening 61, with a length L6, only needs to meet the minimum stroke required for the steel ball 4 to reciprocate within the ball track at the maximum working swing angle of the universal joint, without reserving additional assembly space. By shortening the length L3 of the short window opening 61, the axial width of the intermediate beam between two adjacent sets of window openings 6 is significantly increased. This directly increases the effective load-bearing cross-sectional area of ​​the cage 3 in this area, thereby greatly improving the overall structural strength and torsional stiffness of the cage 3. At the same time, the longer window opening 62, with a length L4, adds an extra length on top of meeting the working stroke. This extra length is mainly used to provide the necessary movement and adjustment space for the steel ball 4 during assembly, thereby ensuring the feasibility of assembly. Through this differentiated design, this embodiment effectively strengthens the overall strength of the cage 3 without sacrificing assemblability.

[0033] As one embodiment of this utility model, please refer to Figure 2 , Figure 3 , Figures 5 to 7 The shape of the inlet structure 5 is a spherical surface, and its radius is greater than or equal to the radius of the steel ball 4.

[0034] In the traditional steel ball assembly process, to insert the steel ball 4 into the gap between the outer star wheel 1 and the inner star wheel 2, the inner star wheel 2 needs to swing relative to the outer star wheel 1 by a large installation angle α (installation angle α is greater than the maximum working swing angle of the ball joint) to form a sufficiently large effective opening size L2 (L2 is the opening distance between the ball track opening of the outer star wheel 1 and the window 6 of the cage 3). However, a large swing angle limits the shortening of the cage window length, thus restricting the improvement of strength. In this embodiment, due to the presence of the guide structure 5, when assembling the steel ball 4, the steel ball 4 first contacts the smooth spherical curved surface and slides smoothly into the ball track under its guidance. This guiding effect greatly reduces the radial pressing force required for assembly, so that with only a small installation angle α, a larger effective opening size L1 can be formed than in the conventional design (L1 is the opening distance between the guide structure 5 at the ball track opening of the outer star wheel 1 and the window 6 of the cage 3, and L1>L2). In other words, assembling the steel ball 4 becomes easier, and the swing angle requirement of the inner star wheel 2 is reduced.

[0035] In this embodiment, the inlet structure 12 can be integrally formed at the ball track opening of the outer star wheel 1 through processes such as precision forging, turning or grinding to form a smooth transition.

[0036] As one embodiment of this utility model, please refer to Figure 9 and Figure 10 The avoidance structure 7 is symmetrically arranged, and at least four of them are symmetrically distributed along the edge of the spherical opening of the outer star wheel 1.

[0037] ΦA is the opening diameter of the spherical surface of the outer star wheel 1, L4 is the length of the long window 62 of the retainer 3, and L5 is the distance between the walls of the opposite long window 62. When ΦA ≥ L5, the retainer 3 can be smoothly installed into the outer star wheel 1. However, in this application, because the window L4 of the retainer 3 is designed to be shorter, the retainer 3 may not be able to be smoothly installed into the outer star wheel 1. If ΦA is increased, it will lead to an increase in the axial clearance of the ball joint and an increase in the shear stress of the intermediate beam of the large swing angle retainer, etc. Therefore, without increasing ΦA, this application designs at least four mutually symmetrical avoidance structures 7 on the spherical opening of the outer star wheel 1. Compared with the original conventional structure, the material of the shaded part in the figure is cut off, and there are at least four mutually symmetrical structures.

[0038] In this embodiment, the avoidance structure 7 is cut along the shaded portion from the opening side to the interface side.

[0039] The working principle of this invention is as follows: while ensuring excellent assemblability of all components (especially the cage 3 and steel balls 4), the structural strength of the cage 3 is significantly improved. Based on this strength margin, key dimensions such as the pitch circle diameter of the universal joint, the outer diameter of the outer star wheel 1, and the outer diameter of the cage 3 can be reduced accordingly, while meeting the same level of torque and life requirements. This allows for further miniaturization and weight reduction of the entire constant velocity universal joint assembly based on the existing eight-ball design. This has significant application value for modern automobiles (especially electric vehicles) where space is limited or where there are stringent requirements for unsprung mass.

[0040] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0041] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A steel ball type constant velocity universal joint, comprising: The device comprises an outer star wheel, an inner star wheel, a cage, and several steel balls. Both the outer and inner star wheels have tracks for the steel balls to roll. The inner star wheel is located inside the outer star wheel and is coaxially arranged. The cage is located between the outer and inner star wheels and has several sets of openings, including short and long openings of different lengths. The number of openings, tracks, and steel balls is equal. Each track on the outer star wheel has an inlet structure on its opening side, and an avoidance structure is provided at the edge of the spherical opening of the outer star wheel.

2. The steel ball type constant velocity universal joint according to claim 1, characterized in that, The short window and the long window are spaced apart along the circumference of the retainer.

3. A steel ball type constant velocity universal joint according to claim 1, characterized in that, The shape of the inlet structure is a spherical surface with a radius greater than or equal to the radius of the steel ball.

4. A steel ball type constant velocity universal joint according to claim 1, characterized in that, The avoidance structure is symmetrically arranged, and at least four of them are symmetrically distributed along the spherical opening edge of the outer star wheel.

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