High-precision forming die and process for chain shaft core
By introducing oil drain grooves and through grooves into the chain shaft core forming mold, and combining them with secondary forming R angles, the problems of air trapping and taper were solved, achieving high-precision forming of the chain shaft core and improving product quality and lifespan.
Patent Information
- Application Number
- CN202511270962.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-08
- Publication Date
- 2025-12-30
AI Technical Summary
The problem of excessively large radius taper caused by air entrapment in the existing chain shaft core forming mold affects product quality and precision.
The design employs an oil drain groove and a through groove to work together to expel gas from inside the mold. Combined with a secondary forming R-angle method, it solves the problems of air trapping and taper, ensuring high-precision forming of the chain shaft core.
It significantly improves the forming accuracy and quality of the chain shaft core, reduces the possibility of air blockage, ensures that the R-angle taper is within 0.05mm, and improves the stress distribution uniformity and service life of the chain shaft core.
Smart Images
Figure CN121222984A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of chain shaft core forming mold technology, and more specifically, to a high-precision chain shaft core forming mold and process. Background Technology
[0002] As a key component in mechanical transmission systems, the precision and reliability of chain axles directly affect the transmission efficiency, service life, and stability of the entire chain. With the increasing demands of modern industry on the performance of transmission components, especially in applications requiring high speed and high load, the manufacturing quality of chain axles is receiving increasing attention. The manufacturing of chain axles primarily relies on metal forming processes, among which cold heading, warm heading, and precision stamping technologies are widely used.
[0003] Currently, in actual production processes, especially in the forming of high-precision shaft cores, the problem of excessive taper at the R-angle of the shaft core caused by air trapped inside the mold has become a key factor restricting the improvement of product quality.
[0004] Therefore, in view of this, we will study and improve the existing structure to provide a high-precision forming mold and process for chain shaft core, in order to achieve a more practical value. Summary of the Invention
[0005] 1. Technical problems to be solved
[0006] To address the problems existing in the prior art, the purpose of this invention is to provide a high-precision forming mold and process for chain shaft cores. It can solve the problem of air trapping, and when used in conjunction with a through groove, it helps to expel gas and further reduces the possibility of air trapping. At the same time, by choosing a secondary forming R-angle method, both the taper problem and the R-angle problem are solved, ensuring the quality of the final produced chain shaft core.
[0007] 2. Technical Solution
[0008] To solve the above problems, the present invention adopts the following technical solution.
[0009] A high-precision forming mold for chain shaft cores includes:
[0010] The mold body is used to form the chain shaft core, and the mold body has a core groove inside;
[0011] A punch, which is inserted directly into the core groove of the mold body, is used to form the chain shaft core;
[0012] The punch is equipped with an oil drain groove to discharge gas from inside the mold and reduce the taper at the R-angle of the shaft core.
[0013] Furthermore, the oil drain groove consists of multiple channels arranged along the axial direction of the punch, and the cross-sectional shape of the channels is arc-shaped or rectangular.
[0014] Furthermore, it also includes a through groove, which is disposed on the side wall of the mold body.
[0015] Furthermore, the openings of the through groove and the oil drain groove are opposite each other when they come into contact.
[0016] A high-precision forming process for chain shaft cores, the specific implementation steps of which are as follows:
[0017] Step 1: Place the material to be processed into the core groove of the mold body and perform initial clamping;
[0018] Step 2: The punch is inserted directly into the core groove of the mold body to shape the material, while the oil drain groove is used to discharge the gas inside the mold.
[0019] Step 3: After the punch is fully pressed into the core groove, the chain shaft core is formed. Then, the chain shaft core is removed, completing the initial forming of the chain shaft core.
[0020] Step 4: Expel the remaining gas through the channel and perform secondary shaping on the R-angle of the chain shaft core to reduce the taper and optimize the R-angle shape.
[0021] Furthermore, in step one:
[0022] Before the material is initially compressed, the straightened wire is precisely cut into cylindrical blanks of predetermined length and volume using a cutting machine;
[0023] When initially compressing the material, trim off any exposed portions.
[0024] Furthermore, in step two:
[0025] The punch is inserted vertically into the core groove using a stamping machine or hydraulic pump. The drain groove allows gas and excess oil to pass through but prevents metal from flowing in.
[0026] Furthermore, in step three:
[0027] During the full insertion of the punch, the punch reaches the bottom dead center and is held at pressure briefly.
[0028] Furthermore, in step four:
[0029] During the secondary forming process, a new punch is used for pressing.
[0030] After the secondary forming, the pressure of the punch is 70% to 90% of the pressure of the initial forming.
[0031] Furthermore, when the oil drain groove and the through groove are in contact, the taper at the R-angle of the shaft core is less than 0.1mm.
[0032] 3. Beneficial effects
[0033] Compared with the prior art, the advantages of this invention are:
[0034] This solution solves the problem of excessive R-angle taper caused by air entrapment in traditional processes by using a coordinated venting design of oil drain groove and through groove. Experimental data shows that the R-angle taper of the shaft core can be stably controlled within 0.05mm, which is 300% more accurate than traditional processes. This improvement makes the stress distribution of the chain shaft core more uniform when it is used in chain drive, effectively avoiding early failure caused by local stress concentration.
[0035] The oil drain groove design of the punch bar solves the problem of air trapping. When used in conjunction with the through groove, it helps to expel gas and further reduces the possibility of air trapping. At the same time, the secondary forming R-angle method solves both the taper and R-angle problems, ensuring the quality of the final produced chain shaft core. Attached Figure Description
[0036] Figure 1 This is a schematic diagram of the high-precision forming mold for the chain shaft core in this invention;
[0037] Figure 2 This is a schematic diagram of the internal structure of the high-precision forming mold for the chain shaft core in this invention;
[0038] Figure 3 This is a schematic diagram of the structure of the mold body in this invention;
[0039] Figure 4 This is a schematic diagram of the punch in this invention;
[0040] Figure 5 This is a schematic diagram of the high-precision forming process of the chain shaft core in this invention.
[0041] Explanation of the labels in the diagram:
[0042] 1. Mold body; 101. Core groove; 102. Through groove; 2. Punch; 3. Oil drain groove. Detailed Implementation
[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0044] Example 1:
[0045] Please see Figure 1 - Figure 4 A high-precision forming mold for chain shaft cores, comprising:
[0046] The mold body 1 is used to form the chain shaft core. The mold body 1 has a core groove 101 inside. The mold body 1 is made of high-strength alloy steel. The machining accuracy of the internal core groove 101 reaches ±0.005mm and the surface roughness Ra≤0.2μm.
[0047] Punch 2 is inserted directly into the core groove 101 of the mold body 1 to form the chain shaft core. Punch 2 is made of hard alloy material and its working end is designed with a 15° guide cone angle to facilitate insertion into the core groove 101.
[0048] The punch 2 is equipped with an oil drain groove 3, which is used to discharge the gas inside the mold and reduce the taper at the R-angle of the shaft core to avoid air entrapment and improve product quality.
[0049] See Figure 4 Specifically, the oil drain groove 3 consists of multiple channels arranged along the axial direction of the punch 2, and the cross-sectional shape of the channels is fan-shaped.
[0050] This ensures the effective drainage of oil in the oil draining tank 3, thus effectively solving the problem of air stagnation.
[0051] Furthermore, the oil drain groove 3 ensures venting performance without affecting the strength of the punch.
[0052] See Figure 2 , Figure 3 Specifically, it also includes a through groove 102, which is provided on the side wall of the mold body 1.
[0053] It can be used to help expel gas, further reducing the possibility of choking.
[0054] The through groove 102 is set on the side wall of the mold body 1, at a 45° angle to the horizontal plane, with a diameter of 2mm, and can form a three-dimensional venting network with the oil drain groove 3.
[0055] Specifically, the openings of the through groove 102 and the oil drain groove 3 are opposite each other when they come into contact.
[0056] The through groove 102 is used in conjunction with the oil drain groove 3 to further reduce the taper at the R-angle of the shaft core.
[0057] Example 2:
[0058] Based on the above embodiment 1, further description is provided.
[0059] See Figure 5 A high-precision forming process for chain shaft cores, the specific implementation steps of the forming process are as follows:
[0060] Step 1: Place the material to be processed into the core groove 101 of the mold body 1 and perform initial clamping;
[0061] Specifically, before initially compressing the material, a cutting machine is used to precisely cut the straightened wire into cylindrical blanks of predetermined length and volume; the length tolerance of the blanks is controlled within ±0.02mm.
[0062] The volume calculation must ensure that it can completely fill the cavity without causing a surge in pressure due to excessive material, which could damage the mold.
[0063] When initially compressing the material, trim off any exposed portions.
[0064] To avoid the impact of sharp parts on subsequent molding, ensure the uniformity of material after the chain shaft core is molded.
[0065] Step 2: The punch 2 is inserted directly into the core groove 101 of the mold body 1 to form the material, while the oil drain groove 3 is used to discharge the gas inside the mold.
[0066] Specifically, a punch 2 is vertically inserted into the core groove 101 using a stamping machine or hydraulic pump. The oil drain groove 3 is usually a very precise tiny slit that allows gas and excess oil to pass through but prevents metal from flowing in.
[0067] The pressing speed of punch 2 can be controlled in three stages: 50 mm / s in the initial stage, 20 mm / s in the forming stage, and 5 mm / s in the final pressing stage.
[0068] Under immense pressure, the billet metal undergoes plastic flow, beginning to fill the R-corner area at the bottom of the core groove 101 and the entire cavity. Smooth venting prevents gas pressure from causing additional resistance to the punch 2 and the mold cavity, or even "spreading" the mold, thus helping to extend the mold's service life.
[0069] Step 3: After the punch 2 is fully pressed into the core groove 101, the chain shaft core is formed. Then, the chain shaft core is removed, and the initial forming of the chain shaft core is completed.
[0070] Specifically, during the complete insertion of punch 2, punch 2 reaches the bottom dead center and holds pressure briefly. The holding time is 0.5 to 1 second, and the pressure is maintained at 200-250 MPa.
[0071] This ensures that the metal undergoes complete plastic deformation, releasing internal stress, reducing springback, and stabilizing dimensions.
[0072] Step 4: Expel the remaining gas through the through groove 102, and perform secondary shaping on the R-angle of the chain shaft core to reduce the taper and optimize the R-angle shape.
[0073] Specifically, during the secondary forming process, a new punch 2 is used for pressing; the new punch 2 is a nano-coated punch with a surface hardness of HRC70 or higher, and the pressure is adjusted to 80% of that used in the initial forming.
[0074] After the secondary forming, the pressure of the punch 2 is 70% to 90% of the pressure of the initial forming.
[0075] Specifically, when the oil drain groove 3 and the through groove 102 are in contact, the taper at the R-angle of the shaft core is less than 0.1mm.
[0076] Example 3
[0077] Further description is provided based on the above embodiments 1 and 2.
[0078] Based on the "high-precision forming process of chain shaft core", a "high-precision forming mold for chain shaft core" was produced, and the forming mold was tested. The statistical results of the experiment are as follows:
[0079] The forming accuracy has been significantly improved, with the core diameter tolerance controlled within ±0.01mm and the R-angle taper ≤0.05mm, which is 50% better than the industry standard;
[0080] The mold life is extended by more than 3 times. The life of an ordinary mold is about 500,000 cycles, while this design can reach 1.5 million cycles.
[0081] Production efficiency increased by 40%, and the single-piece molding cycle was shortened from 12 seconds to 7 seconds;
[0082] The defect rate was reduced from 3% in conventional processes to below 0.2%;
[0083] Significant energy-saving effect, reducing energy consumption per ton of product by 25%;
[0084] The product's fatigue life has been increased by 2 times, and it has been tested to withstand 10 million cycles of load.
[0085] Achieving automated production reduces manual intervention by 80%;
[0086] The mold maintenance cycle has been extended from once a week to once a month.
[0087] Working principle:
[0088] During mold operation, the metal blank undergoes plastic deformation under the pressure of the punch 2. The three-dimensional venting system composed of the oil drain groove 3 and the through groove 102 can promptly discharge the gas in the cavity and avoid the formation of an air cushion effect.
[0089] Specifically, when the punch 2 begins to press down, 30% of the gas is discharged upwards through the oil drain groove 3; when the punch 2 continues to press down to 50% of its stroke, 50% of the gas is discharged laterally through the through groove 102; in the final stage, the remaining gas is completely discharged through the connecting channel between the oil drain groove 3 and the through groove 102. This multi-path exhaust design ensures that the metal flow at the R-angle is not obstructed by gas, thus forming a perfect transition arc.
[0090] In summary, this molding die can solve the problem of air trapping. When used in conjunction with a through-groove, it helps to expel gas, further reducing the possibility of air trapping. Furthermore, the use of a secondary molding method for the radius (R-angle) simultaneously addresses both the taper and R-angle issues, ensuring the quality of the final produced chain shaft core.
[0091] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.
Claims
1. A high-precision forming mold for chain shaft cores, characterized in that: The utility model relates to a chain shaft core forming process and device, and belongs to the field of metal forming technology. The utility model discloses a chain shaft core forming process and device, which comprises a mold body (1) for forming a chain shaft core, a core groove (101) is formed in the inside of the mold body (1), a punch rod (2) is vertically inserted into the inside of the core groove (101) of the mold body (1) to perform forming processing on the chain shaft core, and an oil discharge groove (3) is arranged on the punch rod (2) to discharge gas in the inside of the mold and reduce the taper at the R angle of the shaft core. The oil discharge groove (3) is a plurality of grooves arranged in the axial direction of the punch rod (2), and the cross-sectional shape of the grooves is arc-shaped or rectangular. A through groove (102) is further arranged on the side wall of the mold body (1).
2. The high-precision forming die for a chain core according to claim 1, characterized in that: When the through groove (102) is in contact with the oil discharge groove (3), the openings are opposite to each other.
3. The high-precision forming die for a chain core according to claim 1, characterized in that: The specific implementation steps of the forming process are as follows:
4. The high-precision forming die for a chain core according to claim 3, characterized in that: Step one: the material to be processed is placed in the core groove (101) of the mold body (1) and is preliminarily compressed; 5. A high precision forming process for chain bushings as claimed in any one or more of the claims 1 to 4, characterized in that: Step two: the punch rod (2) is vertically inserted into the inside of the core groove (101) of the mold body (1) to perform forming processing on the material, and the oil discharge groove (3) is used to discharge gas in the inside of the mold; Step three: after the punch rod (2) is completely pressed into the core groove (101), the forming of the chain shaft core is completed, then the chain shaft core is taken out, and the preliminary forming of the chain shaft core is completed; Step four: the remaining gas is discharged through the through groove (102), and the R angle of the chain shaft core is secondarily formed to reduce the taper and optimize the shape of the R angle. In step one: Before the material is preliminarily compressed, a cutting machine is used to accurately cut the straightened wire into cylindrical blank with predetermined length and volume; 6. A high precision forming process for chain bushings as claimed in claim 5 wherein: When the material is preliminarily compressed, the leaked part of the cutting material is cut. In step two: A punch or a hydraulic pump is used to vertically insert the punch rod (2) into the core groove (101), and the oil discharge groove (3) allows gas and excess oil to pass through but prevents metal from flowing in.
7. A high precision forming process for chain bushings as claimed in claim 5 wherein: In step three: During the process of completely pressing the punch rod (2), the punch rod (2) reaches the lower dead point and is temporarily kept at pressure.
8. A high precision forming process for chain bushings as claimed in claim 5 wherein: In step four: During the secondary forming, a new punch rod (2) is used for pressing; 9. A high precision forming process for chain bushings as claimed in claim 5 wherein: After the secondary forming, the pressure of the punch rod (2) is 70% to 90% of the pressure of the primary forming. When the oil discharge groove (3) and the through groove (102) are in contact, the taper at the R angle of the shaft core is less than 0.1 mm. 10. A high precision forming process for chain bushings as claimed in claim 5 wherein: