Novel lightweight structure of transmission shaft universal joint forged piece

Abstract

The utility model discloses a novel light weight structure of a transmission shaft universal joint forging, which comprises a central part and four journals arranged along the circumference of the central part in an array mode, the included angle between two adjacent journals is 90 degrees, the upper surface and the lower surface of the central part are respectively provided with a groove, the two grooves are identical in structure and are symmetrical up and down, the bottom of each groove is round, and the bottom of each groove is provided with a through hole. A groove opening of the groove is a square with four vertexes and four edges of arc transition structures, the side wall of the groove is in curved surface transition from the groove opening to the groove bottom, and vertical projections of the four vertexes of the square are located on the center lines of the four shaft necks respectively. According to the utility model, by improving the structure of the universal joint forge piece, the strength of the easy-to-fail part is enhanced, the deformation resistance is increased, the stress is reduced when the universal joint is stressed, and the fracture failure rate of the universal joint is reduced by 2.5%, so that the aims of prolonging the service life of the universal joint and reducing the failure rate of the universal joint are fulfilled; meanwhile, the depths and the shapes of the grooves in the two sides are enlarged, the weight of the forge piece is effectively reduced, the weight of a single forge piece can be reduced by 0.1 Kg, and the purpose of light weight is achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of automobile industry, and in particular relates to a new lightweight structure of a transmission shaft universal joint forging. Background Art

[0002] A universal joint, or universal joint, is a device that enables variable-angle power transmission. It is used in locations where the direction of the drive axis needs to be changed. It is the "joint" component of the universal joint system in a vehicle's drive system. The combination of a universal joint and a drive shaft is called a universal joint system. The structure and function of a universal joint are somewhat similar to the joints in a human limb: it allows the angle between the connected parts to vary within a certain range. To ensure power transmission and accommodate angular changes caused by steering and vehicle movement, universal joints are often used to connect the drive axles and wheel axles in front-wheel drive vehicles. However, due to axial dimension constraints and the required large deflection angle, a single universal joint cannot ensure equal angular velocity between the output shaft and the input shaft, which can easily cause vibration, damage to components, and generate significant noise. Therefore, various constant velocity joints are widely used. In front-wheel drive vehicles, each axle uses two constant velocity joints: the one closest to the transaxle is the inboard universal joint, and the one closest to the axle is the outboard universal joint. In rear-wheel drive vehicles, the engine, clutch, and transmission are mounted as a single unit on the vehicle frame, while the drive axle is connected to the frame via a flexible suspension. This distance between the two assemblies requires a connection. During operation, uneven road surfaces, load variations, or misalignment between the two assemblies can cause changes in the angle and distance between the transmission output shaft and the drive axle's final drive input shaft. Therefore, rear-wheel drive vehicles utilize a dual universal joint system, with one universal joint at each end of the drive shaft. These joints maintain an equal angle between the two shafts, ensuring that the instantaneous angular velocity of the output and input shafts remains constant.

[0003] There are two main failure modes of universal joints:

[0004] 1. Failure of the four journals of the universal joint due to wear: Since the needle roller bearings on the universal joint assembly repeatedly swing within a small angle during use, when the radial clearance between the journal and the bearing is large, concentrated loads are easily generated. This causes fatigue cracks to form early in the areas with high loads, which then develop into large-scale fatigue spalling. The rings and needle rollers also experience large-scale fatigue spalling. Especially at the journal head, due to the influence of stress concentration, the chamfers of the loaded parts are almost completely eaten away.

[0005] 2. Fracture occurs at the connecting part between adjacent journal shafts: During the use of the whole vehicle, the cross shaft bears stress, resulting in stress concentration at the connecting part between adjacent journal shafts, forming a fracture source. The crack gradually expands, and the stress-bearing strength of the entire cross shaft universal joint gradually decreases, ultimately leading to the fracture failure of the cross shaft.

[0006] The universal joint structure of the traditional structure is as Figures 1-4 shown, including four journal shafts 1. The middle part 2 connected by the four journal shafts 1 is a shallow groove 3 with a diameter of ф26mm, an inclination of 10°, and a depth of 1.5mm. The thickness in area M (the connecting part between two journal shafts 1, with a horizontal distance of 17.5mm from the bottom of the shallow groove 3) and area N does not change, which not only cannot solve the problem of fracture caused by stress concentration in area M but also increases the weight of the universal joint in area N, resulting in waste of raw materials. Utility Model Content

[0007] In order to solve the above technical problems existing in the prior art, the present utility model provides a new lightweight structure of a drive shaft universal joint forging with high strength at the connecting part between adjacent journal shafts and lighter weight.

[0008] To solve the above technical problems, the present utility model adopts the following technical solution: A new lightweight structure of a drive shaft universal joint forging includes a central part and four journal shafts arranged in a circumferential array along the central part. The included angle between adjacent two journal shafts is 90°. Both the upper surface and the lower surface of the central part are provided with a groove. The two grooves have the same structure and are symmetrically arranged up and down. The bottom of the groove is circular, the groove opening is a square with arc transitions at four vertices and four sides, the side wall of the groove is in a curved surface transition from the groove opening to the groove bottom, and the vertical projections of the four vertices of the square are respectively located on the center lines of the four journal shafts.

[0009] The arc transition structures at the four vertices of the square all protrude towards the adjacent journal shafts.

[0010] The arc transition structures of each side of the square all protrude towards the center of the central part.

[0011] The diameter of the circle where the arc transition structures at the four vertices of the square are located is 48mm. The shortest distance from the arc transition structures at the four vertices of the square to the adjacent journal shafts is 3mm. The diameter of the arc transition structures of each side of the square is 21.4mm. The diameter of the bottom of the groove is 24mm. The maximum depth of the groove is 8mm. The horizontal distance from the outside of the connecting part between adjacent two journal shafts to the bottom of the groove is 21mm.

[0012] With the above technical solution, compared with the prior art, the utility model improves both the upper and lower sides of the middle part as follows: the depth of the groove is increased, the bottom diameter of the groove is enlarged, the groove opening is expanded, and the shape of the groove opening extends outward along the center lines of the four journal bearings as much as possible. At the same time, sufficient thickness is reserved at the connecting part between adjacent two journal bearings, that is, while reducing the weight, the strength of the connecting part between the two journal bearings is ensured (the thickness of the connecting part between the two journal bearings is increased from 17.5 mm to 21 mm).

[0013] In summary, by improving the structure of the universal joint forging, the utility model strengthens the strength of the vulnerable parts, increases the deformation resistance, reduces the stress during stress, and reduces the fracture failure rate of the universal joint by 2.5%, achieving the purpose of improving the life of the universal joint and reducing the failure rate of the universal joint; at the same time, by expanding the depth and shape of the grooves on both sides, the weight of the forging is effectively reduced, and the weight of a single forging can be reduced by 0.1 Kg, achieving the purpose of lightweighting. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic plan view of the prior art universal joint forging;

[0015] Figure 2 is Figure 1 the left view of

[0016] Figure 3 is Figure 1 the A-A cross-sectional view in

[0017] Figure 4 is a schematic perspective view of the prior art universal joint forging;

[0018] Figure 5 is a schematic plan view of the utility model;

[0019] Figure 6 is Figure 1 the left view of

[0020] Figure 7 is Figure 1 the B-B cross-sectional view in

[0021] Figure 8 is a schematic perspective view of the utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The following further describes in detail the embodiments of the utility model with reference to the drawings and embodiments.

[0023] Figures 5-8As shown in the figure, the novel lightweight structure of the forging of the drive shaft universal joint of the present utility model includes a central part 2 and four journal shafts 1 arranged in a circumferential array along the central part 2. The included angle between two adjacent journal shafts 1 is 90°. A groove 4 is provided on both the upper surface and the lower surface of the central part 2. The two grooves 4 have the same structure and are symmetrically arranged up and down. The bottom of the groove 4 is circular, and the notch of the groove 4 is a square with the four vertices 5 and the four sides 6 being arc-transition structures. The side wall of the groove 4 is a curved surface transition from the notch to the bottom. The vertical projections of the four vertices 5 of the square are respectively located on the center lines of the four journal shafts 1.

[0024] The arc-transition structures at the four vertices 5 of the square all protrude towards the adjacent journal shaft 1.

[0025] The arc-transition structures of each side 6 of the square all protrude towards the center of the central part 2.

[0026] The diameter of the circle where the arc-transition structures at the four vertices 5 of the square are located is 48 mm, and the shortest distance from the arc-transition structures at the four vertices 5 of the square to the adjacent journal shaft 1 is 3 mm ( Figure 5 in the N part), the diameter of the arc-transition structure of each side 6 of the square is 21.4 mm, the bottom diameter of the groove 4 is 24 mm, the maximum depth of the groove 4 is 8 mm, and the horizontal distance from the outside of the connecting part between two adjacent journal shafts 1 to the bottom of the groove 4 is 21 mm. These dimensions are designed according to the dimensions of the entire universal joint forging itself and to ensure strength.

[0027] Compared with the prior art, the present utility model makes the following improvements to both the upper and lower sides of the middle part: the depth of the groove 4 is increased, the bottom diameter of the groove 4 is increased, the notch is enlarged, the notch shape is extended outward along the center lines of the four journal shafts 1 as much as possible, and at the same time, enough thickness is reserved at the connecting part M between two adjacent journal shafts 1 as much as possible. The weight of the entire forging is reduced, that is, while reducing the weight, the strength of the connecting part between the two journal shafts 1 is ensured (the thickness of the connecting part between the two journal shafts 1 is increased from 17.5 mm to 21 mm).

[0028] The above embodiments illustrate the basic principles and characteristics of the present utility model. However, the above only illustrates the preferred embodiments of the present utility model and is not limited by the described embodiments. Those of ordinary skill in the art, inspired by this patent, without departing from the purpose of the present utility model and the scope protected by the claims, can also make many forms of deformation and improvement, and these all belong to the protection scope of the present utility model. Therefore, the patent and protection scope of the present utility model shall be subject to the appended claims.

Claims

1. A new lightweight structure for a universal joint forging of a transmission shaft, comprising a central part and four journal shafts arranged in a circumferential array along the central part, with an included angle of 90° between adjacent two journal shafts, and characterized in that: There is a groove on both the upper surface and the lower surface of the central part. The two grooves have the same structure and are symmetrically arranged up and down. The bottom of the groove is circular, and the notch of the groove is a square with arc transitions at all four vertices and four sides. The side wall of the groove is a curved surface transition from the notch to the bottom. The vertical projections of the four vertices of the square are respectively located on the center lines of the four journals.

2. The new lightweight structure of the drive shaft universal joint forging according to claim 1, characterized in that: The arc transition structures at the four vertices of the square all protrude towards the adjacent journals.

3. The new lightweight structure of the drive shaft universal joint forging according to claim 2, characterized in that: The arc transition structures on each side of the square all protrude towards the center of the central part.

4. The new lightweight structure of the drive shaft universal joint forging according to claim 3, characterized in that: The diameter of the circle where the arc transition structures are located at the four vertices of the square is 48 mm. The shortest distance between the arc transition structures at the four vertices of the square and the adjacent journals is 3 mm. The diameter of the arc transition structures on each side of the square is 21.4 mm. The bottom diameter of the groove is 24 mm. The maximum depth of the groove is 8 mm. The horizontal distance between the outer side of the connecting part between two adjacent journals and the bottom of the groove is 21 mm.

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