Improved forging structure of the inner coupling of the ball cage type constant velocity universal coupling

Abstract

The present invention discloses an improved forging structure of the inner coupling of a ball cage type constant velocity universal coupling, wherein the forging structure includes a plurality of rolling grooves evenly distributed on its spherical outer peripheral surface, protrusions formed between the rolling grooves, and an upper circular concave hole and a lower circular concave hole located at the center of the upper and lower end surfaces of the forging, wherein the depth of the upper circular concave hole is greater than the depth of the lower circular concave hole, and a ring structure is formed upward from the lower end surface of the forging structure, corresponding to the depth of the lower circular concave hole. The forging structure design of the present invention can reduce the contact surface between the forming blank and the cavity, thereby reducing the forming load, reducing the deformation of the mold, and improving the forming accuracy of the rolling groove; in addition, by reducing the forming load, the stress in the mold is reduced, thereby improving the life of the mold; by improving the forming accuracy of the rolling groove, the grinding thickness allowance of the rolling groove surface is small and stable, ensuring the uniform organization and uniform hardness of the rolling surface, which is of great significance.

Description

Technical Field

[0001] The invention belongs to the field of forging processing of vehicle parts, and in particular relates to a forging structure of an improved inner coupling of a ball cage type constant velocity universal coupling. Background Art

[0002] As a conventional forming method, Japanese Patent Application Publication No. 57-56132 describes a forging method for the inner coupling of a ball cage type constant velocity universal joint. Figure 1 As shown, the forging structure 102 of the inner coupling of the constant velocity universal joint under this forging method adopts the following structure: a plurality of rolling grooves 105 are evenly distributed on the spherical outer peripheral surface, protrusions 109 are formed between the rolling grooves 105, circular concave holes 106 and 107 of equal depth are opened in the upper and lower centers, and an unopened bamboo-shaped structure 108 is left between the upper circular concave hole 106 and the lower circular concave hole 107. Figure 3 As shown, in the subsequent punching process, a hole 110 is punched out to prepare for the subsequent internal hole machining.

[0003] As attached Figure 2 As shown, the forging die structure and forming process of the inner coupling forging structure 102 of the constant velocity universal joint are typically formed by closing the upper and lower dies (1, 2) to form a closed cavity. The blank 100 is placed in the closed cavity, and the punch 4 extrudes the material to fill the upper and lower dies (1, 2) and the punch 5 to form a closed cavity 3 until the forming is complete. As the press rises, the upper die 1 separates from the lower die 2, and the punch 5 then lifts the finished forging structure 102. This allows the finished forging structure 102 to be demolded from the lower die 2.

[0004] Under the forming structure and forming process of the inner coupling forging structure 102 of the existing constant velocity universal joint, when the blank 100 is filled in the upper and lower molds, in order to ensure that the blank is fully filled during molding, the blank 100 forms a large contact area with the blocked cavity, which requires high-load pressurization of the press. The high-load pressurization of the press acts on the blank, causing the blank to form high pressure on the inner surface of the blocked cavity. The deformation of the mold is related to the pressure on the inner surface of the cavity. The higher the pressure, the greater the deformation of the mold. The high pressure on the inner surface of the cavity causes the mold to deform greatly, and a mold with a large deformation cannot forge a high-precision product. At the same time, the high pressure acting on the inner surface of the cavity increases the deformation of the mold, resulting in an increase in stress inside the mold. The increase in excessive stress inside the mold is a direct cause of the short life of the mold.

[0005] During production, it is necessary to promptly monitor the filling status of the cavity formed by the blank and the upper and lower dies to adjust the press stroke. Overfilling or underfilling are both detrimental to production. Overfilling results in high loads, reduced forging accuracy, and reduced die life, while underfilling results in scrap. Summary of the Invention

[0006] The purpose of the present invention is to provide an improved forging structure of the inner coupling of a ball cage type constant velocity universal joint, which adopts a new forging shape to ensure the accuracy of the inner coupling raceway groove, reduce the forming load, and improve the die life and material utilization.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0008] The improved forging structure of the inner coupling of a ball cage-type constant velocity universal joint includes a plurality of rolling grooves 105 evenly distributed on its spherical outer circumference, protrusions 109 formed between the rolling grooves, and an upper circular recessed hole 106 and a lower circular recessed hole 107 located at the center of the upper and lower end surfaces of the forging. The depth of the upper circular recessed hole 106 is greater than the depth of the lower circular recessed hole 107. Furthermore, a ring-shaped structure F is formed upward from the lower end surface of the forging structure 102, corresponding to the depth of the lower circular recessed hole 107, for reinforcement. This structure is used to ensure the annular wall thickness L between the rolling groove 105 and the lower circular recessed hole 107. During the subsequent punching process, the bamboo-shaped structure 108 located between the two recessed hole openings is removed by the punch. During the punching and removal process, the ring-shaped structure F is used to prevent deformation of the lower portion of the rolling groove 105, thereby ensuring the accuracy of the finished rolling groove 105 after forging.

[0009] Preferably, a prismatic protrusion G is provided between the protrusion 109 and the rolling groove 105, which is used to observe with the naked eye whether the groove surface of the rolling groove is sufficiently well formed after forming. In this way, the press can be adjusted in time to avoid high load on the press. At the same time, the prismatic protrusion G is also a mark for subsequent machining allowance.

[0010] Preferably, the depth of the upper circular concave hole 106 is greater than 10 mm, and the depth of the lower circular concave hole 107 is 0 to 10 mm.

[0011] Preferably, the rolling groove 105 is in an arc shape.

[0012] In addition, in addition to being applicable to the arc-shaped rolling groove forming used in the background technology Japanese patent, the above-mentioned forging structure is also applicable to the rolling groove forming of a combination of a straight bar upper section and an arc-shaped lower section. Therefore, as a preference, the shape of the rolling groove 105 can also be a combination of a straight bar upper section and an arc-shaped lower section.

[0013] Preferably, the number of the rolling grooves 105 is 4, 6, 8 or 10, and most preferably, the number of the rolling grooves 105 is 6 or 8.

[0014] The above technical solution was chosen based on the following considerations:

[0015] The inventors found that in the prior art, in order to facilitate the forging of the inner coupling and ensure that the forging accuracy is not affected when the bamboo-shaped structure in the middle of the forging is punched, the prior art solution is that the depth of the circular recessed holes in the upper and lower centers is roughly the same. As described in this background technology, there is a problem of excessive forming load. The high load leads to a series of problems such as increased mold deformation, increased stress in the mold, and decreased forging accuracy.

[0016] In order to ensure sufficient forging accuracy and increase the life of the forging die, the forming load must be reduced, thereby reducing die deformation and internal stress. The most effective way to reduce the forming load is to reduce the contact area between the forming material and the die.

[0017] Through repeated experiments, the inventors found that reducing the depth of the lower circular concave hole 107 and deepening the depth of the upper circular concave hole 106 can optimize the flow of the forming material and make the material flow toward the lower end tip 111 where filling is difficult, thereby achieving an overall uniform filling effect, ensuring the gap between the outer surface and the mold, and effectively reducing the contact area between the forming material and the mold in the blocked cavity.

[0018] The new forging structure optimizes the flow of the forming material, ensuring a gap between the outer surface of the forging and the die. This allows the press to fully fill and form the material even under low-load conditions. Because the outer surface of the forging will subsequently require machining, sufficient cutting allowance is required. While this allows for sufficient cutting allowance, the outer surface of the forging does not need to contact the die to ensure accuracy. Therefore, a gap can be left between the outer surface of the forging and the die, reducing the contact area between the two. By reducing the contact area between the outer surface and the die, the forging load is reduced, and while the forming dimensions are acceptable, the amount of stock used can also be reduced.

[0019] The excessively shallow lower circular recess 107 reduces or even eliminates the average wall thickness distance L between the raceway groove and the lower circular recess. During the subsequent punching process of the bamboo-shaped structure between the two recesses, the lateral pulling caused by punching pushes the thinner wall portion adjacent to the punched hole inward, damaging the precision of the already formed raceway groove. Therefore, the inventors of the present invention made further design decisions.

[0020] To address the lateral drag caused by the shallow lower circular recess 107 during punching, the inventors added an upward annular structure F to the lower end surface of the forged product. This ensures the distance L between the raceway groove and the central lower circular recess, eliminating lateral drag and maintaining the precision of the formed raceway groove. Secondly, a prismatic protrusion G was added between the protrusion 109 and the raceway groove 105. This can be used on-site to observe whether the outer surface is fully formed, allowing for timely adjustment of the press stroke to avoid excessive load on the press. The prismatic protrusion G also serves as a marker for subsequent machining allowance, preventing scrap.

[0021] The beneficial effects of the present invention are:

[0022] The forging structure of the inner coupling of the improved ball cage type constant velocity universal coupling of the present invention is ingeniously conceived. Since the performance of the ball cage type constant velocity universal coupling is largely affected by the accuracy and surface structure of the raceway groove of the coupling, the high accuracy, good surface structure and hardness of the raceway groove ensure the performance of the coupling. The forging structure design of the present invention optimizes the flow of the forming material by reducing the depth of the lower circular concave hole and deepening the depth of the upper circular concave hole, which can reduce the contact area between the forming blank and the closed cavity and reduce the forming load. By reducing the forming load, excessive deformation of the mold and excessive increase in stress in the mold are avoided, thereby improving the accuracy of the raceway groove, making the raceway groove surface structure good and the hardness uniform, which is of great significance for manufacturing constant velocity universal couplings with excellent reliability and high performance. In addition, with the When forging forgings, an annular structure F that plays a supporting role when punching is forged first is forged, which can ensure that the accuracy of the roller groove is not affected when punching is performed after forming while reducing the depth of the lower circular concave hole, thereby ensuring the accuracy of the roller groove; more preferably, when forging an additional prismatic protrusion G that plays a role in indicating sufficient filling is forged, it can further facilitate the production site to observe whether the outer surface forming is sufficient, facilitate the load control of the press, and is extremely practical. The annular structure F and the prismatic protrusion G forged during forging will be removed in subsequent processing after completing their mission, and will not affect the smoothness of the arc-shaped roller surface on the roller groove; and compared with the original structure, reducing the forming load saves energy consumption, improves material utilization, and increases mold life, so the present invention as a whole has strong practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] For ease of explanation, the present invention is described in detail with reference to the following specific embodiments and accompanying drawings.

[0024] Figure 1 A schematic diagram of a longitudinal cross-section of an inner coupling forging of a qualified constant velocity universal coupling according to background technology;

[0025] Figure 2 A diagram showing the forming process of an inner coupling forging of a constant velocity universal coupling of background technology;

[0026] Figure 3 This is a schematic diagram of the three-dimensional structure of the constant velocity universal joint of the present invention in an inverted state after the bamboo-shaped structure of the inner coupling forging structure is washed away;

[0027] Figure 4 Schematic diagram of the longitudinal cross-section of the inner coupling forging structure of the constant velocity universal coupling of the present invention;

[0028] Figure 5 middle Figure 5-1A schematic diagram of the longitudinal cross-section structure and the flow direction of the formed material of the inner coupling forging of a medium-speed universal coupling when the upper and lower circular concave holes are of the same depth in the background art; Figure 5-2 A longitudinal cross-sectional structure of an inner coupling forging of a constant velocity universal coupling of the present invention and a schematic diagram of the flow direction of formed materials;

[0029] Figure 6 This is a schematic diagram showing the deformation of the wall between the raceway groove and the lower circular concave hole under load when punching the middle bamboo-shaped structure when the lower circular concave hole of the inner coupling forging of the constant velocity universal coupling is too shallow and no annular structure is provided;

[0030] Figure 7 is a schematic diagram of a cross-section structure when the rolling groove is in a combination of a straight strip and an arc shape;

[0031] Figure 8 It is a schematic diagram of the longitudinal cross-section structure of the inner coupling forging structure of the constant velocity universal coupling of the present invention when the annular structure F and the prismatic protrusion G are removed in the subsequent processing after the bamboo-shaped structure is punched out. DETAILED DESCRIPTION

[0032] like Figure 3 、 Figure 4 As shown, the forging structure of the inner coupling of the improved ball cage type constant velocity universal coupling, the forging structure 102 includes a plurality of rolling grooves 105 evenly distributed on its spherical outer peripheral surface, protrusions 109 formed between the rolling grooves 105, and an upper circular concave hole 106 and a lower circular concave hole 107 located at the center of the upper and lower end surfaces of the forging, the depth of the upper circular concave hole 106 is greater than the depth of the lower circular concave hole 107, and a ring structure F for reinforcement is formed upward from the lower end surface of the forging structure 102, corresponding to the depth of the lower circular concave hole 107, to ensure the average wall thickness distance L between the rolling groove 105 and the lower circular concave hole 107, so as to ensure that when the bamboo-shaped structure 108 located between the two concave holes is subsequently punched, the ring here has sufficient strength to ensure that the rolling groove 105 is not deformed and the forming accuracy of the rolling groove 105 is maintained.

[0033] The depth of the upper circular concave hole 106 is greater than 10 mm, and the depth of the lower circular concave hole 107 is 0 to 10 mm.

[0034] A prismatic protrusion G is also provided between the protrusion 109 and the rolling groove 105, which is used to observe with the naked eye whether the groove surface of the rolling groove is sufficiently well formed during forming after forming, so as to adjust the press stroke in time to prevent excessive load. At the same time, the prismatic protrusion G is also a mark of subsequent machining allowance.

[0035] The shape of the rolling groove 105 is arc-shaped or straight-bar-shaped. In addition to being applicable to the arc-shaped rolling groove forming used in the background art Japanese patent, the above-mentioned forging structure is also applicable to the rolling groove forming of a combination of a straight-bar upper section and an arc-shaped lower section. Figure 3 、 Figure 4 As shown, the rolling groove 105 is in the shape of an arc. Figure 7 As shown, the shape of the rolling groove 105 is a combination of a straight bar in the upper section and an arc in the lower section, and the straight bar and the arc transition smoothly in the middle.

[0036] The depth of the upper circular concave hole 106 is greater than 10 mm, and the depth of the lower circular concave hole 107 is 0 to 10 mm.

[0037] like Figure 3 and 4 , the shape of the rolling groove 105 is arc-shaped.

[0038] The number of the rolling grooves 105 is 4, 6, 8 or 10. Optimally, the number of the rolling grooves 105 is 6 or 8. In this embodiment, the number of the rolling grooves 105 is 6.

[0039] The above technical solution was chosen based on the following considerations:

[0040] The inventors found that in the prior art, in order to facilitate the forging of the inner coupling and ensure that the forging accuracy is not affected when the bamboo-shaped structure in the middle of the forging is punched, the prior art solution is that the depth of the circular recessed holes in the upper and lower centers is roughly the same. As described in this background technology, there is a problem of excessive forming load. The high load leads to a series of problems such as increased mold deformation, increased stress in the mold, and decreased forging accuracy.

[0041] In order to ensure sufficient forging accuracy and increase the life of the forging die, the forming load must be reduced, thereby reducing die deformation and internal stress. The most effective way to reduce the forming load is to reduce the contact area between the forming material and the die.

[0042] like Figure 5 of Figure 5-1 and Figure 5-2 As shown, through repeated experiments, the inventors found that reducing the depth of the lower circular concave hole 107 and deepening the depth of the upper circular concave hole 106 can optimize the flow of the forming material, so that the material flows purposefully to the lower end tip 111 where filling is difficult, thereby achieving an overall uniform filling effect, ensuring the gap between the outer surface and the mold, and effectively reducing the contact area between the forming material and the mold in the blocked cavity.

[0043] The new forging structure optimizes the flow of the forming material, ensuring a gap between the outer surface of the forging and the die. This allows the press to fully fill and form the material even under low-load conditions. Because the outer surface of the forging will subsequently require machining, sufficient cutting allowance is required. While this allows for sufficient cutting allowance, the outer surface of the forging does not need to contact the die to ensure accuracy. Therefore, a gap can be left between the outer surface of the forging and the die, reducing the contact area between the two. By reducing the contact area between the outer surface and the die, the forging load is reduced, and while the forming dimensions are acceptable, the amount of stock used can also be reduced.

[0044] like Figure 6 As shown, the overly shallow lower circular recess 107 causes the average wall thickness distance L between the raceway groove and the lower circular recess to decrease or even disappear. During the subsequent punching process of the bamboo-shaped structure between the two recesses, the lateral pulling caused by punching causes the thinner wall portion adjacent to the punching hole to tilt inward, damaging the precision of the already formed raceway groove. Therefore, the inventors of the present invention further developed a design.

[0045] To address the lateral drag caused by the shallow lower circular recess 107 during punching, the inventors added a reinforcing annular structure F to the lower end surface of the forged product. This ensures the distance L between the raceway groove and the central lower circular recess, eliminating lateral drag and maintaining the precision of the formed raceway groove. Secondly, a prismatic protrusion G was added between the protrusion 109 and the raceway groove 105. This can be used on-site to observe whether the outer surface is fully formed, allowing timely adjustments to the press stroke to avoid excessive loads on the press. The prismatic protrusion G also serves as a marker for subsequent machining allowances, preventing scrap.

[0046] The forging method of the inner coupling forging structure of the improved ball cage type constant velocity universal coupling adopts the following method: Figure 2 The background technology shown is based on the mold used, that is, the processing mold includes an upper mold 1 and a lower mold 2, and a cavity 3 is provided in the middle of the upper mold 1 and the lower mold 2 after the upper mold 1 and the lower mold 2 are closed. An upper punch 4 that moves up and down is provided in the center of the upper mold 1, and a lower punch 5 that moves up and down is provided in the center of the lower mold 2. The lower end of the upper punch 4 is stepped, and there is a gap between the upper end of the lower punch 5 and the lower mold 2, and the cavity 3 is provided with multiple ball track rolling grooves; the cavity 3 is composed of the upper mold 1, the lower mold 2, the upper punch 4, and the lower punch 5, which are adapted to the structure of the inner coupling of the constant velocity universal joint; then, according to the depth requirements of the upper and lower circular concave holes 106 and 107, the length of the upper punch 4 is correspondingly increased, the length of the lower punch 5 is shortened, and according to the requirement of forming the annular structure F, a circle of annular concave grooves is left around the lower punch 5 in the lower mold 2. Similarly, according to the requirement of forming the prismatic protrusion G, a corresponding strip structure is provided between each rolling groove and the protrusion in the cavity 3. The blank 100 is then press-formed in a mold having the above features.

[0047] The forming steps are:

[0048] The upper punch 4 is retracted into the upper die 1 , and the upper die 1 and the lower die 2 are separated to expose the cavity 3 . The blank 100 is placed upright in the cavity 3 in the lower die 2 . The diameter of the blank 100 is smaller than that of the cavity 3 .

[0049] The press drives the upper mold 1 to move downward through the pressure device 8, and keeps the mold closed with the lower mold 2 to form a blockage.

[0050] The press drives the upper punch 4 to press down to the maximum stroke, and the upper punch 4 and the lower punch 5 squeeze the blank 100 to fill the upper and lower molds 1, 2 and the upper and lower punches 4, 5 to form a closed cavity until the forming is completed.

[0051] At this time, the annular structure F on the lower end face of the forged product and the ridge-shaped protrusions G added between each rolling groove and the protrusion are also formed.

[0052] Then, as the press machine rises, the upper and lower dies 1 and 2 open, and the lower punch 5 lifts the forged product, thereby achieving demoulding of the forged product and the lower die.

[0053] The forging structure of the inner coupling of the improved ball cage type constant velocity universal coupling of the present invention is ingeniously conceived. Since the performance of the ball cage type constant velocity universal coupling is largely affected by the accuracy and surface structure of the raceway groove of the coupling, the high accuracy, good surface structure and hardness of the raceway groove ensure the performance of the coupling. The forging structure design of the present invention optimizes the flow of the forming material by reducing the depth of the lower circular concave hole 107 and deepening the depth of the upper circular concave hole 106, which can reduce the contact area between the forming blank and the closed cavity and reduce the forming load. By reducing the forming load, excessive deformation of the mold and excessive increase of stress in the mold are avoided, thereby improving the accuracy of the raceway groove and making the surface structure of the raceway groove good and Uniform hardness is of great significance for manufacturing constant velocity universal couplings with excellent reliability and high performance. In addition, when forging forgings, the annular structure F that plays a supporting role when punching is forged first can ensure that the accuracy of the raceway groove 105 is not affected when punching is performed after forming under the condition of reducing the depth of the lower circular recessed hole 107, thereby ensuring the accuracy of the raceway groove 105. When the prismatic protrusion G that plays a role of indicating that the filling is sufficient is forged during forging, it can be further facilitated to observe whether the outer surface forming is sufficient at the production site, and it is convenient for the load control of the press, which is highly practical. After the annular structure F and the prismatic protrusion G forged during forging have completed their mission, they will be processed and removed in the subsequent processing, as shown in the attached figure. Figure 8As shown in the figure, the left side is the structure before processing, and the right side is a processing schematic diagram, which mainly involves the trimming of the inner hole, the trimming of the outer protrusion and the trimming of the end face. In this way, the forged annular structure F and the prismatic protrusion G are removed without affecting the smoothness of the arc-shaped roller surface on the raceway groove; and compared with the original structure, reducing the forming load saves energy consumption, improves material utilization, and increases the life of the mold, so the present invention as a whole has strong practicality.

[0054] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that are not conceived through creative work should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection defined in the claims.

Claims

1. An improved forging structure of an inner coupling of a ball cage type constant velocity universal coupling, wherein the forging structure (102) comprises a plurality of rolling grooves (105) uniformly distributed on its spherical outer peripheral surface, protrusions (109) formed between the rolling grooves (105), and an upper circular concave hole (106) and a lower circular concave hole (107) located at the center of the upper and lower end surfaces of the forging, characterized in that: The depth of the upper circular concave hole (106) is greater than the depth of the lower circular concave hole (107), and a ring structure (F) is formed upward from the lower end surface of the forging structure (102) corresponding to the depth of the lower circular concave hole (107); a ridge-shaped protrusion (G) is also provided between the protrusion (109) and the rolling groove (105); the depth of the upper circular concave hole (106) is more than 10 mm, and the depth of the lower circular concave hole (107) is 0 to 10 mm.

2. The forging structure of the inner coupling of the improved ball cage type constant velocity universal coupling according to claim 1 is characterized in that: The rolling groove (105) is in the shape of an arc.

3. The forging structure of the inner coupling of the improved ball cage type constant velocity universal coupling according to claim 1 is characterized in that: The rolling groove (105) is in the shape of a combination of a straight strip in the upper section and an arc in the lower section.

4. The forging structure of the inner coupling of the improved ball cage type constant velocity universal coupling according to claim 1 is characterized in that: The number of the rolling grooves (105) is 4, 6, 8 or 10.

5. The forging structure of the inner coupling of the improved ball cage type constant velocity universal coupling according to claim 4 is characterized in that: The number of the rolling grooves (105) is 6 or 8.

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