A machining process and machining device for an integrated chain sleeve

Abstract

The application discloses a processing technology and a processing device of an integrated chain sleeve, and the processing technology of the integrated chain sleeve comprises the following steps: processing raw materials to form a sleeve blank in a cylindrical shape, thereby obtaining A blank; performing first cold heading treatment on the A blank, so that a convex part is formed outwardly in the middle of the A blank, step pipes are formed at both ends of the A blank, and a hollow circular platform is formed between the convex part and the step pipes, thereby obtaining B blank; performing second cold heading treatment on the B blank, so that the length of the step pipes at both ends is increased after the second cold heading treatment, the length of the convex part is shortened after the second cold heading treatment, and the taper of the hollow circular platform is unchanged and the length of the hollow circular platform is increased after the second cold heading treatment, thereby obtaining C blank; and performing third cold heading treatment on the C blank, so that the outer wall of the hollow circular platform in the C blank is inwardly recessed to form a right angle after the third cold heading treatment, thereby obtaining a finished chain sleeve. The application can realize cold heading forming of the chain sleeve.

Description

Technical Field

[0001] This invention relates to a chain sleeve, and more particularly to a processing technology and processing device for an integral chain sleeve. Background Technology

[0002] Traditionally, chain sleeves used in automotive chains achieve stepped shapes at both ends by nesting two cylinders together, utilizing the difference in length and inner / outer diameter of the two cylinders to form the steps. However, this type of chain sleeve is structurally complex and has high production costs. Furthermore, it creates an installation gap between the two cylinders, reducing the stability and performance of the chain sleeve during subsequent use.

[0003] To address the aforementioned defects, some manufacturers are attempting to process chain bushings using a cold heading process. This involves using a cylindrical blank as the raw material and stretching and compressing both ends of the blank using a cold heading die to create a stepped structure. However, this method has a drawback in practice: because the stepped shape of some chain bushings undergoes greater deformation compared to the cylindrical shape, if the cold heading die is used for a single-step cold heading process, the chain bushing may deform and crack at the stepped area, compromising the quality of the cold heading.

[0004] Based on the above, while multiple cold heading processes can reduce the deformation of the billet during each cold heading, achieving cold heading of the stepped structure, dead spots easily form at the metal edges of the steps during the cold heading process, affecting the forming quality of the stepped area. For example, when the single-sided thickness of the step is 0.9mm and the step depth is 2mm, the metal below the step needs to flow downwards during the cold heading process, while the billet above the step needs to flow upwards. Furthermore, the metal at the step location suffers from reduced flowability due to its narrow thickness, preventing it from flowing smoothly and quickly in both directions during deformation. This results in micro-cracks on the inner and outer sidewalls of the step area after cold heading, failing to meet the manufacturer's quality requirements for the chain bushing. Due to these limitations, current cold heading processes cannot achieve cold heading of this chain bushing.

[0005] Therefore, existing cold heading equipment cannot achieve stable processing of chain sleeves. Summary of the Invention

[0006] The purpose of this invention is to provide a processing technology and apparatus for an integrated chain sleeve. It enables cold heading forming of the chain sleeve.

[0007] The technical solution of this invention: a processing technology for an integrated chain sleeve, comprising the following steps:

[0008] ① The raw material is processed to form a cylindrical sleeve blank, resulting in blank A;

[0009] ② Perform the first cold heading treatment on billet A to form an outward convex part in the middle of billet A, and form stepped tubes at both ends of billet A. A hollow frustum is formed between the convex part and the stepped tubes to obtain billet B.

[0010] ③ Perform a second cold heading process on billet B, so that the length of the stepped tubes at both ends increases after the second cold heading process, the length of the protrusions decreases after the second cold heading process, and the taper of the hollow truncated cone remains unchanged and its length increases after the second cold heading process, thus obtaining billet C.

[0011] ④ Perform a third cold heading process on the C billet, so that the outer wall of the hollow truncated cone in the C billet is concave inward to form a right angle after the third cold heading process, to obtain the finished chain sleeve.

[0012] In the aforementioned processing technology of an integrated chain sleeve, let the thickness of blank A in step ① be the first thickness, let the thickness of the stepped tube of blank B in step ② be the second thickness, let the length of the stepped tube of blank B be the first length, and let the thickness of the stepped tube of blank C in step ③ be the third thickness, and let the length of the stepped tube of blank B be the second length.

[0013] The first thickness is 1 to 1.5 mm;

[0014] The second thickness is reduced by 0.2 to 0.3 mm relative to the first thickness, and the first length is 1 to 1.5 mm;

[0015] The third thickness is reduced by 0.2 to 0.3 mm relative to the second thickness, and the second length is increased by 0.6 to 0.8 mm relative to the first length.

[0016] In the aforementioned processing technology of an integrated chain sleeve, in step ②, the side wall taper of the hollow frustum of blank B is 40°, and the length of the hollow frustum of blank B is 0.6-0.7 mm; in step ③, the length of the hollow frustum of blank C is increased by 0.6-0.7 mm compared with the length of the hollow frustum of blank B in step ②.

[0017] The processing device used in the aforementioned processing technology of an integrated chain sleeve includes a first cold heading assembly, a second cold heading assembly, and a third cold heading assembly. Each of the first, second, and third cold heading assemblies includes a fixed mold frame and a moving mold frame. The fixed mold frame contains a fixed mold core, and a stop tube is slidably connected to the middle of the fixed mold core. The moving mold frame contains a moving mold core, and a punch and an ejector tube are respectively connected to the middle of the moving mold core. The punch and the ejector tube are nested and slidably connected. The fixed mold core, the stop tube, the moving mold core, the punch, and the ejector tube, when enclosed, form a forming cavity for cold heading the blank.

[0018] The first cold heading assembly is used to perform a first cold heading process on billet A, so that a protruding part is formed in the middle of billet A, and stepped tubes are formed at both ends of billet A, and a hollow frustum is formed between the protruding part and the stepped tubes at both ends.

[0019] The second cold heading assembly is used to perform a second cold heading process on the B billet, so that the length of the stepped tubes at both ends increases after the second cold heading process, the length of the protrusions decreases after the second cold heading process, and the inclination of the hollow truncated cone remains unchanged and its length increases after the second cold heading process.

[0020] The third cold heading assembly is used to perform a third cold heading process on the C billet, so that the hollow frustum sidewall of the C billet is concave inward to form a right angle after the third cold heading process.

[0021] In the aforementioned processing device, the end of the baffle tube extends to the inner side of the fixed mold frame and is connected to a return block. The return block is slidably connected inside the fixed mold frame and connected to the fixed mold frame via an elastic element.

[0022] In the aforementioned processing device, a positioning block is fixedly connected to the inner side of the moving mold frame, and one end of the punch is fastened and connected inside the positioning block.

[0023] In the aforementioned processing device, a groove is formed in the fixed mold frame on one side of the positioning block. One end of the ejector tube extends into the groove and is connected to an ejector block. A drive rod is connected to the end of the ejector block away from the ejector tube. The end of the drive rod passes through the ejector tube and the fixed mold frame and extends to the outside.

[0024] In the aforementioned processing device, the fixed mold core includes a first fixed mold core, a second fixed mold core, and a third fixed mold core, and the movable mold core includes a first movable mold core, a second movable mold core, and a third movable mold core. The first fixed mold core and the first movable mold core are respectively disposed in the fixed mold frame and the movable mold frame of the first cold heading assembly. The second fixed mold core and the second movable mold core are respectively disposed in the fixed mold frame and the movable mold frame of the second cold heading assembly. The third fixed mold core and the third movable mold core are respectively disposed in the fixed mold frame and the movable mold frame of the third cold heading assembly.

[0025] Compared with the prior art, the present invention has the following characteristics:

[0026] (1) By limiting the cold heading process, the present invention enables the two sides of the sleeve blank to form a hollow truncated cone after the first cold heading treatment, and uses the hollow truncated cone to perform a second cold heading treatment on the base of the sleeve blank. This eliminates the dead point of the sleeve blank at the connection between the stepped tube and the protrusion through the hollow truncated cone, enhances the metal flow effect of the stepped tube at this part, avoids the micro cracks caused by the stepped tube being too narrow in thickness and too large in deformation, and improves the cold heading quality of the sleeve blank.

[0027] (2) Based on the above, by performing a third cold heading process on the sleeve blank at the hollow truncated cone, the outer wall of the hollow truncated cone can be extruded to form an end corner, thereby ensuring the end corner effect of the chain sleeve at the stepped tube. On the other hand, since the metal of the hollow truncated cone flows towards the protrusion during the third cold heading process, while the length and thickness of the stepped tube remain unchanged, the stepped tube will not have micro-cracks at the connection due to the difficulty of metal flow in this state, further improving the cold heading quality of the sleeve blank. With the above combination, the present invention can eliminate the micro-cracks in the sleeve blank caused by the defects of the cold heading process, thereby realizing the cold heading of the sleeve blank.

[0028] (3) Based on the cold heading process, the present invention enables the processing device to perform three cold heading processes on the sleeve blank by limiting the structure of the processing device, and improves the forming effect of the chain sleeve after cold heading.

[0029] Therefore, the present invention can realize the cold heading of chain sleeves. Attached Figure Description

[0030] Figure 1 This is the process flow diagram of Example 1;

[0031] Figure 2 This is a flow chart of the existing cold heading process for chain sleeves;

[0032] Figure 3 yes Figure 2 A diagram showing the forming state during the fourth cold heading process;

[0033] Figure 4 This is a structural schematic diagram of Example 2;

[0034] Figure 5 This is a schematic diagram of the structure of the first cold heading assembly in Embodiment 2.

[0035] The labels in the attached diagram are as follows: 1-First cold heading assembly, 2-Second cold heading assembly, 3-Third cold heading assembly, 4-Fixed mold frame, 5-Moving mold frame, 6-Fixed mold core, 7-Block tube, 8-Moving mold core, 9-Punch, 10-Ejector tube, 11-Return block, 12-Elastic element, 13-Positioning block, 14-Ejector block, 15-Drive rod, 100-Protrusion, 200-Step tube, 300-Hollow frustum. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0037] Example 1. A processing technology for an integrated chain sleeve, the process flow diagram is as follows: Figure 1 As shown, it includes the following steps:

[0038] ① The raw material is processed to form a cylindrical sleeve blank, resulting in blank A;

[0039] ② Perform a first cold heading process on billet A, so that a protruding part 100 is formed in the middle of billet A, and stepped tubes 200 are formed at both ends of billet A. A hollow frustum 300 is formed between the protruding part 100 and the stepped tubes 200 to obtain billet B.

[0040] ③ Perform a second cold heading process on billet B, which increases the length of the stepped tubes at both ends after the second cold heading process, shortens the length of the protrusion 100 after the second cold heading process, and keeps the taper of the hollow truncated cone 300 unchanged and increases its length after the second cold heading process, thus obtaining billet C.

[0041] ④ Perform a third cold heading process on the C billet, so that the outer wall of the hollow frustum 300 in the C billet is concave inward to form a right angle after the third cold heading process, to obtain the finished chain sleeve.

[0042] Let the thickness of billet A in step ① be the first thickness, the thickness of the stepped tube 200 of billet B in step ② be the second thickness, and the length of the stepped tube 200 of billet B be the first length, the thickness of the stepped tube 200 of billet C in step ③ be the third thickness, and the length of the stepped tube 200 of billet B be the second length, and the thickness of the stepped tube 200 of the finished chain sleeve in step ④ be the fourth thickness, and the length of the stepped tube 200 of billet B be the third length.

[0043] The first thickness is 1.28 mm;

[0044] The second thickness is 1.04 mm, and the first length is 1.44 mm;

[0045] The third thickness is 0.87 mm, and the second length is 2.17 mm;

[0046] The fourth thickness is 0.89 mm, and the third length is 2 mm.

[0047] In step ②, the side wall taper of the hollow frustum 300 of billet B is 40°, and the length of the hollow frustum 300 of billet B is 0.63 mm; in step ③, the length of the hollow frustum 300 of billet C is 1.3 mm.

[0048] The existing cold heading process flow diagram for chain sleeves is as follows: Figure 2As shown, the sleeve blank is first cold-forged in the third process to form stepped tubes 200 at both ends. Then, the stepped tubes 200 are further formed in the fourth cold-forging process, achieving the predetermined length and thickness. Finally, the inner hole of the sleeve blank is processed in the fifth and sixth cold-forging processes to obtain the finished chain sleeve. The forming state of the sleeve blank during the fourth cold-forging process is shown in the diagram below. Figure 3 As shown, during the cold heading process of the sleeve blank, the stepped tube 200 at the lower end of the sleeve blank needs to be extended from 2.05mm to 2.15mm in length through the cold heading process. Furthermore, it is fixed in a fixed state by the fixed shaft and the fixed mold core on both sides, resulting in a dead angle at point Q of the sleeve blank. Specifically, the stepped tube 200 below point Q needs to be extended downwards by extrusion, while the sleeve blank above point Q needs to be extended upwards by extrusion, causing the metal at point Q to flow in both directions. Simultaneously, since the thickness of the stepped tube 200 at this point is only 0.85mm, the fluidity of the metal at point Q is relatively weak, making it difficult to achieve rapid flow in both directions under external extrusion. This can lead to micro-cracks at the joint during deformation.

[0049] Based on the above, this embodiment completely changes the cold heading process for the chain sleeve. First, the sleeve blank is pre-treated to form a cylindrical blank A. Then, a first cold heading process forms a protrusion 100 in the middle and a stepped tube 200 at both ends of blank A, creating a hollow frustum 300 between the protrusion 100 and the stepped tube 200. A second cold heading process is then performed based on the hollow frustum 300, allowing the metal from the protrusion 100 to flow through the hollow frustum 300 to the stepped tube 200 during the cold heading process. Combined with the limiting effect of the cold heading die, the stepped tube 200 elongates and its outer diameter shrinks accordingly. With the above-mentioned coordination, this embodiment avoids the reverse flow of metal at the hollow frustum 300 during the cold forging process, and the metal of the protrusion 100 can also flow smoothly into the stepped tube 200 through the hollow frustum 300; thereby effectively avoiding dead points and cracks in the stepped tube 200 during the deformation process.

[0050] After the stepped tube 200 is formed, the outer wall of the hollow frustum 300 can be squeezed from the inclined surface into a right angle shape by the third cold heading treatment of the C blank, thereby achieving the final forming effect of the chain sleeve.

[0051] Example 2. Processing apparatus, configured as follows Figure 4-5As shown, the processing device is used to process the sleeve blank according to the process of Embodiment 1. Specifically, it includes a first cold heading assembly 1, a second cold heading assembly 2, and a third cold heading assembly 3. The first cold heading assembly 1, the second cold heading assembly 2, and the third cold heading assembly 3 all include a fixed mold frame 4 and a moving mold frame 5. The fixed mold frame 4 is provided with a fixed mold core 6, and a baffle tube 7 is slidably connected to the middle of the fixed mold core 6. The moving mold frame 5 is provided with a moving mold core 8, and a punch 9 and an ejector tube 10 are respectively connected to the middle of the moving mold core 8. The punch 9 and the ejector tube 10 are nested and slidably connected. The fixed mold core 6, the baffle tube 7, the moving mold core 8, the punch 9, and the ejector tube 10 form a forming cavity for cold heading the blank after being enclosed.

[0052] The first cold heading assembly 1 is used to perform a first cold heading process on billet A, so that a protruding part is formed in the middle of billet A, and stepped tubes are formed at both ends of billet A, and a hollow frustum is formed between the protruding part and the stepped tubes at both ends.

[0053] The second cold heading assembly 2 is used to perform a second cold heading process on the B billet, so that the length of the stepped tubes at both ends increases after the second cold heading process, the length of the protrusions decreases after the second cold heading process, and the inclination of the hollow truncated cone remains unchanged and its length increases after the second cold heading process.

[0054] The third cold heading assembly 3 is used to perform a third cold heading process on the C billet, so that the hollow frustum sidewall of the C billet is recessed inward to form a right angle after the third cold heading process.

[0055] The end of the baffle tube 7 extends to the inner side of the fixed mold frame 4 and is connected to the return block 11. The return block 11 is slidably connected in the fixed mold frame 4 and connected to the fixed mold frame 4 via the elastic element 12.

[0056] The inner side of the moving mold frame 5 is fastened to a positioning block 13, and one end of the punch 9 is fastened to the positioning block 13.

[0057] A groove is formed in the fixed mold frame 4 on one side of the positioning block 13. One end of the ejector tube 10 extends into the groove and is connected to the ejector block 14. The ejector block 14 is slidably connected in the groove. A drive rod 15 is connected to the end of the ejector block 14 away from the ejector tube 10. The end of the drive rod 15 passes through the ejector tube 10 and the fixed mold frame 4 and extends to the outside.

[0058] The fixed mold core 6 includes a first fixed mold core, a second fixed mold core, and a third fixed mold core. The movable mold core 8 includes a first movable mold core, a second movable mold core, and a third movable mold core. The first fixed mold core and the first movable mold core are respectively disposed in the fixed mold frame 4 and the movable mold frame 5 of the first cold heading assembly 1. The second fixed mold core and the second movable mold core are respectively disposed in the fixed mold frame 4 and the movable mold frame 5 of the second cold heading assembly 2. The third fixed mold core and the third movable mold core are respectively disposed in the fixed mold frame 4 and the movable mold frame 5 of the third cold heading assembly 3.

[0059] This embodiment limits the structure of the processing device to enable cold heading of the sleeve blank according to the steps of Embodiment 1. In use, the blank is first transported between the fixed mold core 6 and the moving mold core 8 by clamps. Then, an external drive device moves the moving mold frame 5 towards the fixed mold frame 4, and the punch 9 pushes the blank into the fixed mold core 6 during the movement. After the blank enters the fixed mold core 6, one end of the blank is limited by the cooperation of the fixed mold core 6 and the stop tube 7. Simultaneously, the moving mold core 8, punch 9, and ejector tube 10 compress the blank from the other end, causing it to be cold-headed under compression. After the blank is formed, the moving mold frame 5 retracts, and the punch 9 drives the blank to detach from the fixed mold core 6. Then, the drive rod 15 drives the ejector tube 10 outward via the ejector block 14, causing the blank to be compressed and detached from the punch 9. The clamps then re-close to clamp the blank, thus achieving one cold heading operation. Based on this, the blank can be cold-forged three times in sequence by the cooperation of the first cold-forging assembly 1, the second cold-forging assembly 2 and the third cold-forging assembly 3, so as to turn the round tube sleeve blank into a chain sleeve of a specified shape.

Claims

1. A processing device for an integrated chain sleeve, characterized in that: The assembly includes a first cold heading component (1), a second cold heading component (2), and a third cold heading component (3). Each of the three components includes a fixed mold frame (4) and a moving mold frame (5). The fixed mold frame (4) contains a fixed mold core (6), and a baffle tube (7) is slidably connected to the middle of the fixed mold core (6). The moving mold frame (5) contains a moving mold core (8), and a punch (9) and an ejector tube (10) are respectively connected to the middle of the moving mold core (8). The punch (9) and the ejector tube (10) are nested together and slidably connected. The fixed mold core (6), the baffle tube (7), the moving mold core (8), the punch (9), and the ejector tube (10) together form a forming cavity for cold heading the blank. The first cold heading assembly (1) is used to perform the first cold heading process on the A billet, so that the middle part of the A billet forms an outwardly protruding part, the two ends of the A billet form stepped tubes, and a hollow frustum is formed between the protruding part and the stepped tubes at both ends. The second cold heading assembly (2) is used to perform a second cold heading process on the B billet, so that the length of the stepped tubes at both ends increases after the second cold heading process, the length of the protrusions decreases after the second cold heading process, and the inclination of the hollow truncated cone remains unchanged and its length increases after the second cold heading process. The third cold heading assembly (3) is used to perform a third cold heading process on the C billet, so that the hollow frustum sidewall of the C billet is recessed inward to form a right angle after the third cold heading process; A positioning block (13) is fixedly connected to the inner side of the moving mold frame (5), and one end of the punch (9) is fastened to the positioning block (13); A groove is formed in the fixed mold frame (4) on one side of the positioning block (13). One end of the ejector tube (10) extends into the groove and is connected to the ejector block (14). The ejector block (14) is connected to a drive rod (15) at the end away from the ejector tube (10). The end of the drive rod (15) passes through the ejector tube (10) and the fixed mold frame (4) and extends to the outside. The fixed mold core (6) includes a first fixed mold core, a second fixed mold core and a third fixed mold core, and the moving mold core (8) includes a first moving mold core, a second moving mold core and a third moving mold core. The first fixed mold core and the first moving mold core are respectively disposed in the fixed mold frame (4) and the moving mold frame (5) of the first cold heading assembly (1). The second fixed mold core and the second moving mold core are respectively disposed in the fixed mold frame (4) and the moving mold frame (5) of the second cold heading assembly (2). The third fixed mold core and the third moving mold core are respectively disposed in the fixed mold frame (4) and the moving mold frame (5) of the third cold heading assembly (3).

2. The processing device for the integrated chain sleeve according to claim 1, characterized in that: The end of the baffle tube (7) extends to the inside of the fixed mold frame (4) and is connected to a return block (11). The return block (11) is slidably connected in the fixed mold frame (4) and connected to the fixed mold frame (4) via an elastic element (12).

3. A processing technology for an integrated chain sleeve, characterized in that: The processing technology is carried out using the processing device for the integrated chain sleeve as described in claim 1 or 2, and specifically includes the following steps: ① The raw material is processed to form a cylindrical sleeve blank, resulting in blank A; ② Perform the first cold heading treatment on billet A to form an outward convex part in the middle of billet A, and form stepped tubes at both ends of billet A. A hollow frustum is formed between the convex part and the stepped tubes to obtain billet B. ③ Perform a second cold heading process on billet B, so that the length of the stepped tubes at both ends increases after the second cold heading process, the length of the protrusions decreases after the second cold heading process, and the taper of the hollow truncated cone remains unchanged and its length increases after the second cold heading process, thus obtaining billet C. ④ Perform a third cold heading process on the C billet, so that the outer wall of the hollow truncated cone in the C billet is concave inward to form a right angle after the third cold heading process, to obtain the finished chain sleeve.

4. The processing technology of an integrated chain sleeve according to claim 3, characterized in that: Let the thickness of billet A in step ① be the first thickness, the thickness of the stepped tube of billet B in step ② be the second thickness, and the length of the stepped tube of billet B be the first length, and the thickness of the stepped tube of billet C in step ③ be the third thickness, and the length of the stepped tube of billet B be the second length. The first thickness is 1 to 1.5 mm; The second thickness is reduced by 0.2 to 0.3 mm relative to the first thickness, and the first length is 1 to 1.5 mm; The third thickness is reduced by 0.2 to 0.3 mm relative to the second thickness, and the second length is increased by 0.6 to 0.8 mm relative to the first length.

5. The processing technology of an integrated chain sleeve according to claim 3, characterized in that: In step ②, the side wall taper of the hollow frustum of billet B is 40°, and the length of the hollow frustum of billet B is 0.6 to 0.7 mm; in step ③, the length of the hollow frustum of billet C is increased by 0.6 to 0.7 mm compared with the length of the hollow frustum of billet B in step ②.

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