Forging die for universal joint light-weight forge piece

Abstract

The utility model discloses a universal joint lightweight forge piece forging die which comprises an upper pressing die and a lower fixed die which correspond to each other up and down, a cross-shaped die cavity is defined between the bottom face of the upper pressing die and the top face of the lower fixed die, the cross-shaped die cavity comprises a center cavity and four shaft cavities, and the structures of the cross-shaped die cavity in the upper pressing die and the lower fixed die are symmetrical up and down; a protruding block is arranged at the center of the bottom face of the center cavity in the lower fixed die, the top face of the protruding block is a round face, four ribs are evenly arranged on the edge of the round face of the protruding block, and the outer end of each rib is connected with the inner end of one shaft cavity. According to the utility model, the internal structure of the cross-shaped die cavity is improved, so that the strength of the easy-to-fail part of the universal joint forge piece is enhanced, the deformation resistance is increased, the stress is reduced when the universal joint forge piece is stressed, the fracture failure rate of the universal joint in the use process is reduced, and the purposes of prolonging the service life of the universal joint and reducing the failure rate of the universal joint are achieved; meanwhile, the weight of the universal joint forge piece is effectively reduced, 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 forging die for a universal joint lightweight forging. Background Art

[0002] A universal joint is a component that enables variable-angle power transmission and is used in locations where the direction of the transmission axis needs to be changed. It is the "joint" component of the universal joint device in the automobile drive system. The failure types of universal joints during use are mainly divided into the following two types:

[0003] 1) Failure of the four journals of the universal joint due to wear: Because 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.

[0004] 2) The connection between two adjacent axle necks is subjected to stress and fracture: During the use of the vehicle, the cross shaft is subjected to stress, which causes stress concentration at the connection between the two adjacent axle necks, forming a fracture source. The crack gradually expands, and the stress strength of the entire cross shaft universal joint gradually decreases, eventually leading to the fracture and failure of the cross shaft.

[0005] The universal joint is manufactured by forging technology. The traditional structure of the universal joint forging is as follows: Figure 1-Figure 4 As shown, it includes four journals 1. The surfaces on both sides of the middle part 2 connected by the four journals 1 are provided with a shallow groove 3. The thickness in area M (the connection part between the two journals 1, the horizontal distance from the bottom of the groove 3) and area N is relatively small, which can not solve the problem of fracture caused by stress concentration in area M, but also increase the weight of the universal joint in area N, resulting in waste of raw materials.

[0006] Since the universal joint forgings are made of forging dies, the optimization and improvement of the universal joint forgings requires structural improvement of the forging dies. Utility Model Content

[0007] In order to solve the above technical problems existing in the prior art, the utility model provides a forging die for a lightweight universal joint forging, which can forge a universal joint forging with high structural strength, not prone to failure and lighter weight.

[0008] In order to solve the above technical problems, the utility model adopts the following technical solutions: a forging die for a lightweight forging of a universal joint, comprising an upper pressure die and a lower fixed die corresponding to each other, the bottom surface of the upper pressure die and the top surface of the lower fixed die forming a cross-shaped die cavity and an annular burr bin located outside the cross-shaped die cavity, the cross-shaped die cavity comprising a central cavity and four axial cavities, the structures of the cross-shaped die cavity inside the upper pressure die and inside the lower fixed die being symmetrical up and down; a protrusion is provided in the lower fixed die at the center of the bottom surface of the central cavity, the top surface of the protrusion is a circular surface, and four ribs are evenly arranged on the edge of the circular surface, the ribs are inclined from high to bottom from the middle to the outside, and the outer end of each rib is connected with the inner end of an axial cavity.

[0009] The side wall and the bottom of the inner wall of the central cavity between two adjacent axial cavities are both concave structures.

[0010] An anti-drift guide block is respectively provided at the four corners of the bottom surface of the upper pressing die, and an anti-drift step groove corresponding to the anti-drift guide block is respectively provided at the four corners of the top surface of the lower fixed die.

[0011] An ejection hole communicating with the cross-shaped mold cavity is vertically opened inside the lower fixed mold. The upper end of the ejection hole is located at the center of the circular surface of the top of the protrusion. A pneumatic ejector rod is arranged in the ejection hole.

[0012] The inner edge of the annular burr bin is cross-shaped and is arranged around the outer edge of the cross-shaped mold cavity.

[0013] Compared to existing technologies, this technical solution employs a protrusion and four ribs at the top and bottom of the central cavity of the cross-shaped die. This increases the depth of the groove in the middle portion of the forged universal joint where the four journals connect, reducing the weight of the forged universal joint. Furthermore, the sidewalls and bottom of the inner wall of the central cavity between adjacent journals are concave, resulting in a greater thickness at the connection between adjacent journals in the universal joint forging, reducing weight while maintaining strength at the connection.

[0014] During forging, the blank is placed in the cross-shaped die cavity of the lower fixed die. When the upper die forges the blank downward, the four anti-drift guide blocks move downward along the corresponding anti-drift step grooves to prevent the horizontal forging force between the upper die and the blank from causing lateral displacement of the upper die, thereby ensuring the quality of the universal joint forging.

[0015] After forging is completed, the upper die is lifted and the universal joint forging will stick to the lower fixed die. At this time, the pneumatic ejector is started, and the upper end of the pneumatic ejector presses the universal joint forging upward. The universal joint forging and the burrs around it are lifted up, and the worker uses pliers to take out the universal joint forging.

[0016] During the forging process, excess blank material enters the annular burr bin through the parting surface between the bottom surface of the upper die and the top surface of the lower fixed die and is stored there. The inner edge of the annular burr bin is cross-shaped and is set around the outer edge of the cross-shaped die cavity. After forging, a thin circle of material is formed around the four journals of the universal joint forging. This is the trimming location, which facilitates the subsequent trimming process.

[0017] To sum up, the utility model improves the internal structure of the cross-shaped mold cavity, so that the strength of the universal joint forging is strengthened at the failure-prone parts, the deformation resistance is increased, the stress when subjected to force is reduced, and the fracture failure rate of the universal joint during use is reduced, thereby achieving the purpose of increasing the life of the universal joint and reducing the failure rate of the universal joint; at the same time, it effectively reduces the weight of the universal joint forging, achieving the purpose of lightweighting. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the planar structure of the existing universal joint forging;

[0019] Figure 2 yes Figure 1 Axial cross-sectional view of

[0020] Figure 3 yes Figure 1 Middle AA section view;

[0021] Figure 4 It is a schematic diagram of the three-dimensional structure of the existing universal joint forging;

[0022] Figure 5 This is a schematic diagram of the vertical cross-sectional structure of the utility model;

[0023] Figure 6 yes Figure 5 Top view of the middle and lower fixed molds;

[0024] Figure 7 yes Figure 5 Schematic diagram of the three-dimensional structure of the middle and upper die;

[0025] Figure 8 yes Figure 5 Schematic diagram of the three-dimensional structure of the middle and lower fixed molds;

[0026] Figure 9 The utility model is a three-dimensional structural diagram of a universal joint lightweight forging forged by the utility model. DETAILED DESCRIPTION

[0027] The following is a further detailed description of the embodiments of the present invention in conjunction with the accompanying drawings and examples.

[0028] Figure 5-Figure 8As shown, the forging die for a lightweight forging of a universal joint of the present invention comprises an upper die 4 and a lower fixed die 5 corresponding to each other. The bottom surface of the upper die 4 and the top surface of the lower fixed die 5 form a cross-shaped die cavity 6 and an annular burr bin 7 located outside the cross-shaped die cavity 6. The cross-shaped die cavity 6 comprises a central cavity 10 and four axial cavities 11. The structures of the cross-shaped die cavity 6 inside the upper die 4 and the lower fixed die 5 are symmetrical from top to bottom. A protrusion 8 is provided at the center of the bottom surface of the central cavity 10 in the lower fixed die 5. The top surface of the protrusion 8 is a circular surface. Four ribs 9 are evenly arranged on the edge of the circular surface. The ribs 9 are inclined from high to bottom from the middle to the outside. The outer end of each rib 9 is connected with the inner end of an axial cavity 11.

[0029] The sidewalls and bottom of the inner wall of the central cavity 10 between two adjacent axial cavities 11 are both concave structures 12 .

[0030] An anti-drift guide block 13 is provided at each of the four corners of the bottom surface of the upper pressing die 4 , and an anti-drift step groove 14 corresponding to the anti-drift guide block 13 is provided at each of the four corners of the top surface of the lower fixed die 5 .

[0031] An ejection hole 15 communicating with the cross-shaped mold cavity 6 is vertically opened inside the lower fixed mold 5 . The upper end of the ejection hole 15 is located at the center of the circular surface on the top of the protrusion 8 . A pneumatic ejector rod 16 is provided in the ejection hole 15 .

[0032] The inner edge 17 of the annular burr bin 7 is cross-shaped and is arranged around the outer edge of the cross-shaped mold cavity 6 .

[0033] A bump 8 and four ribs 9 are provided at the top and bottom of the center cavity 10 of the cross-shaped die 6. This increases the depth of the groove 3 in the middle portion 2 where the four journals 1 of the forged universal joint forging are connected, reducing the weight of the universal joint forging. At the same time, the side walls and bottom of the inner wall of the center cavity 10 between two adjacent journals 11 are formed into a concave structure 12. This makes the connection between two adjacent journals 1 of the universal joint forging have a greater thickness, that is, while reducing weight, the strength of the connection between the two journals 1 is guaranteed. Figure 9 The schematic diagram of the structure of the lightweight forging of the universal joint after trimming is shown.

[0034] During forging, the blank is placed in the cross-shaped die cavity 6 of the lower fixed die 5. When the upper die 4 forges the blank downward, the four anti-deviation guide blocks 13 move downward along the corresponding anti-deviation step grooves 14 to avoid the horizontal forging force between the upper die 4 and the blank causing the upper die 4 to produce lateral displacement, thereby ensuring the quality of the universal joint forging.

[0035] After forging is completed, the upper die 4 is lifted and the universal joint forging will be bonded to the lower fixed die 5. At this time, the pneumatic ejector 16 is started, and the upper end of the pneumatic ejector 16 presses the universal joint forging upward. The universal joint forging and the burrs around it are lifted up, and the worker uses pliers to take out the universal joint forging.

[0036] The annular burr bin 7 is set up so that during the forging process, excess blank enters the annular burr bin 7 through the parting surface between the bottom surface of the upper pressing die 4 and the top surface of the lower fixed die 5 and is stored. The inner edge 17 of the annular burr bin 7 is cross-shaped and is set around the outer edge of the cross-shaped die cavity 6. After forging, a thin circle of material is formed around the outside of the four journals 1 of the universal joint forging. This is the trimming position, which facilitates the subsequent trimming process.

[0037] The above embodiments illustrate the basic principles and features of the present invention. However, the above merely illustrates preferred embodiments of the present invention and is not intended to limit the present invention to the embodiments described. Persons skilled in the art, inspired by this patent, may make various modifications and improvements without departing from the spirit of the present invention and the scope of protection of the claims, all of which fall within the scope of protection of the present invention. Therefore, the patent and scope of protection of this utility model shall be subject to the appended claims.

Claims

1. A forging die for a lightweight universal joint forging comprises an upper pressing die and a lower fixed die corresponding to each other. The bottom surface of the upper pressing die and the top surface of the lower fixed die form a cross-shaped die cavity and an annular burr bin located outside the cross-shaped die cavity. The cross-shaped die cavity comprises a central cavity and four axial cavities, and is characterized by: The structures of the cross-shaped mold cavity inside the upper pressure mold and the lower fixed mold are symmetrical up and down; a convex block is provided at the center of the bottom surface of the central cavity in the lower fixed mold, the top surface of the convex block is a circular surface, and four ribs are evenly provided on the edge of the circular surface of the convex block. The ribs are inclined from the middle to the outside from the high to the bottom, and the outer end of each rib is connected with the inner end of an axis cavity.

2. The forging die for a lightweight universal joint according to claim 1, characterized in that: The side wall and the bottom of the inner wall of the central cavity between two adjacent axial cavities are both concave structures.

3. The forging die for a lightweight universal joint according to claim 1 or 2, characterized in that: An anti-drift guide block is respectively provided at the four corners of the bottom surface of the upper pressing die, and an anti-drift step groove corresponding to the anti-drift guide block is respectively provided at the four corners of the top surface of the lower fixed die.

4. The universal joint lightweight forging die according to claim 1 or 2, characterized in that: An ejection hole communicating with the cross-shaped mold cavity is vertically opened inside the lower fixed mold. The upper end of the ejection hole is located at the center of the circular surface of the top of the protrusion. A pneumatic ejector rod is arranged in the ejection hole.

5. The universal joint lightweight forging die according to claim 1 or 2, characterized in that: The inner edge of the annular burr bin is cross-shaped and is arranged around the outer edge of the cross-shaped mold cavity.

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