A method for preparing a y-shaped ring for a clutch system

Abstract

This invention belongs to the field of automotive hydraulic seal manufacturing technology, specifically relating to a method for manufacturing Y-rings for clutch systems. Addressing the inherent contradiction in existing Y-ring technologies where a single formulation cannot simultaneously achieve root extrusion resistance and high elasticity and low friction at the lip, this invention employs a customized dual-formula design with separate functions. Through integrated co-extrusion of the two formulations, a near-net-shape pre-forming process without interfaces is achieved. Combined with in-mold gradient temperature directional vulcanization and ultrasonic-assisted processes, in-situ chemical bonding and self-lubricating film formation at the lip are simultaneously completed. Finally, the finished product is obtained through a two-stage gradient vulcanization. This method allows for precise control of the performance of different functional areas of the Y-ring, solving pain points in existing processes such as lip damage from trimming, easy peeling of the self-lubricating coating, and excessive compression set. The resulting Y-ring exhibits significantly improved sealing performance, wear life, and extrusion resistance. The production process is short, yield is high, and costs are controllable, making it directly adaptable to industrial mass production and fully meeting the stringent operating requirements of automotive clutch systems.

Description

Technical Field

[0001] This invention belongs to the field of automotive hydraulic seal manufacturing technology, specifically relating to a method for manufacturing a clutch system Y-ring. Background Technology

[0002] The Y-ring is a core dynamic sealing element in automotive hydraulic clutch systems, primarily assembled on the piston assemblies of the clutch master cylinder and slave cylinder. Its performance directly determines the hydraulic pressure stability, operational reliability, and service life of the clutch system. Currently, the Y-ring for clutch systems is mainly manufactured using compression molding or injection molding processes, both of which have the following inherent, insurmountable defects:

[0003] Firstly, existing processes all employ a single, integral formula design, while the root and lip of the Y-ring have completely contradictory performance requirements: the root needs high rigidity and high extrusion resistance to withstand the high-pressure impact of the clutch system and prevent collapse and deformation after long-term use; the lip needs high elasticity, low friction, and high resilience to ensure dynamic sealing and reduce wear. A single formula can only balance and compromise between these two properties, unable to achieve both simultaneously. This results in finished products that either lack sufficient extrusion resistance or have poor sealing and resilience, easily leading to problems such as a soft clutch pedal, excessive free travel, incomplete disengagement, and gear grinding during shifting.

[0004] Secondly, existing molding / injection processes all have mold-closing flash, which is mostly concentrated in the sealing lip area. It must be processed by freezing or manual trimming, which can easily cause defects such as lip scratches, folding, and insufficient glue, leading to sealing failure. The industry's average yield rate is only 85%-90%. At the same time, the presence of the parting line on the lip will cause discontinuity in the sealing surface, further increasing the risk of leakage.

[0005] Third, in order to reduce the friction coefficient of the lip, the existing process mostly adopts the method of secondary coating of PTFE lubricating layer after vulcanization. The coating and the rubber matrix are physically bonded, and the bonding force is weak. Under the conditions of high-frequency reciprocating motion of clutch system and immersion in brake fluid, it is very easy to fall off, lose the low friction effect, and result in a significant shortening of product life.

[0006] Fourth, the existing process uses overall constant temperature vulcanization, which cannot accurately control the crosslinking density for different areas. The internal stress generated during the vulcanization process cannot be effectively eliminated, resulting in large permanent compression deformation of the finished product. After long-term use, the resilience performance decays rapidly, and the sealing stability is poor.

[0007] To address the aforementioned issues, the industry has attempted to prepare Y-rings with different properties through adhesive bonding. However, the adhesive interface presents a significant risk of delamination and is prone to cracking under high-pressure impact and alternating high and low temperature conditions, failing to meet the requirements for automotive safety components and thus hindering industrial application.

[0008] In view of this, the present invention provides a method for preparing a Y-ring for a clutch system to meet production requirements. Summary of the Invention

[0009] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a Y-ring for a clutch system, comprising the following steps:

[0010] S1. Functional dual-formulation compounding: High-rigidity anti-extrusion compound A for the root of the Y-ring and high-elasticity low-friction self-lubricating compound B for the lip of the Y-ring are prepared separately; compound A adopts a peroxide vulcanization system and compound B adopts a sulfur vulcanization system, and the vulcanization initiation temperature of compound B is lower than that of compound A, providing a basis for subsequent gradient vulcanization.

[0011] S2. Dual-formula integrated co-extrusion preforming: Compound A and compound B are co-extruded in a viscous flow state through a twin-screw co-extrusion equipment and a shaped co-extrusion die to obtain an integrated shaped rubber strip that perfectly matches the cross-section of the Y-ring. After cutting, an annular preform is obtained. The shaped co-extrusion die is equipped with independent A-rubber feeding chambers and B-rubber feeding chambers. The two feeding chambers correspond to the root area and lip area of ​​the Y-ring, respectively, to achieve a 1:1 precise match between the formulation and the functional area.

[0012] S3. In-mold gradient heating directional vulcanization: The annular preform is placed in a zoned temperature-controlled mold. After the mold is closed, the root area is first subjected to a first stage of directional vulcanization to complete the main cross-linking of compound A. Then, the temperature is increased to perform a second stage of vulcanization on the lip area to complete the full cross-linking of compound B. At the same time, a chemically bonded self-lubricating layer is formed in situ on the lip surface. Ultrasonic-assisted vibration is applied throughout the vulcanization process to eliminate internal stress and improve the uniformity of cross-linking.

[0013] S4. Gradient two-stage post-vulcanization and finished product processing: The vulcanized semi-finished product undergoes gradient temperature two-stage post-vulcanization, and after cleaning and testing, the finished product is obtained.

[0014] As a preferred embodiment of the Y-ring preparation method for the clutch system of the present invention, the formulation components of the compound A, by mass parts, are: 100 parts of high acrylonitrile-content nitrile rubber, 55-70 parts of composite reinforcing agent, 2.5-3.5 parts of peroxide vulcanizing agent, 1.5-2 parts of crosslinking agent, 2-3.5 parts of composite antioxidant, and 5-8 parts of extract-resistant plasticizer; the acrylonitrile-content nitrile rubber has an acrylonitrile mass fraction of 34%-40%, ensuring excellent brake fluid resistance and basic rigidity.

[0015] In a preferred embodiment of the Y-ring preparation method for a clutch system according to the present invention, the composite reinforcing agent is a mixture of high abrasion-resistant carbon black N330 and fumed silica in a mass ratio of (4-5):1; the peroxide curing agent is DCP; the crosslinking agent is TAIC; the composite antioxidant is a mixture of antioxidant RD and antioxidant 4010NA; and the extraction-resistant plasticizer is DOS.

[0016] As a preferred embodiment of the Y-ring preparation method for the clutch system of the present invention, the formulation components of the compound B, by mass, are: 100 parts of nitrile butadiene rubber with medium acrylonitrile content, 30-43 parts of low-reinforcing filler system, 2.3-3.5 parts of sulfur vulcanization system, 8-12 parts of PTFE-grafted maleic anhydride modifier, 2-3 parts of composite antioxidant, 6-9 parts of low-temperature resistant plasticizer, and 0.5-1 parts of internal lubricant; the acrylonitrile mass fraction of the nitrile butadiene rubber with medium acrylonitrile content is 26%-33% to balance the brake fluid resistance and high rebound performance.

[0017] As a preferred embodiment of the Y-ring preparation method for the clutch system of the present invention, the low-reinforcing filler system is a mixture of fast-extruded carbon black N550 and nano-montmorillonite, with a mass ratio of (5-7):1; the sulfur vulcanization system includes sulfur, accelerator CZ and accelerator TMTD; the composite antioxidant is a mixture of antioxidant MB and antioxidant 4020; the low-temperature resistant plasticizer is DOA; and the internal lubricant is calcium stearate.

[0018] In a preferred embodiment of the Y-ring preparation method for the clutch system of the present invention, in step S2, the twin-screw co-extrusion equipment is equipped with two independent feeding systems and temperature control systems. The extrusion temperature control temperature of compound A is 55-65℃, and the extrusion temperature control temperature of compound B is 50-60℃. The cross-sectional dimensional tolerance of the shaped rubber strip is controlled within ±0.03mm, the single-piece weight error of the annular preform is controlled within ±0.02g, and the cut end face is treated with a 45° bevel butt joint.

[0019] In a preferred embodiment of the Y-ring preparation method for a clutch system according to the present invention, in step S3, the partitioned temperature control mold has two sets of independently temperature-controlled heating systems built in, corresponding to the root temperature control area and the lip temperature control area respectively. The mold parting surface is set on the non-sealing surface at the root of the Y-ring, completely avoiding the sealing lip area, thus preventing flash and parting line from appearing on the sealing working surface from the source.

[0020] As a preferred embodiment of the Y-ring preparation method for the clutch system of the present invention, in step S3, the process parameters for the first-stage directional vulcanization are: root temperature control zone temperature 170-180℃, lip temperature control zone temperature 120-130℃, clamping pressure 15-20MPa, and vulcanization time 5-8min; the process parameters for the second-stage vulcanization are: lip temperature control zone temperature raised to 150-160℃, constant temperature vulcanization time 3-5min, and clamping pressure kept constant throughout the process. During this stage, the compound rubber B completes full cross-linking and simultaneously achieves in-situ self-lubricating film formation.

[0021] In a preferred embodiment of the Y-ring fabrication method for a clutch system according to the present invention, the process parameters for ultrasonic-assisted vibration in step S3 are: ultrasonic frequency 20-30kHz, power density 0.5-0.8W / cm². 2 The vibration continues throughout the entire vulcanization process.

[0022] As a preferred embodiment of the Y-ring preparation method for the clutch system of the present invention, in step S4, the gradient two-stage post-vulcanization process is as follows: first, heat at 100°C for 2 hours, then heat to 120°C and heat for 2 hours, with nitrogen protection throughout the process.

[0023] In a preferred embodiment of the Y-ring preparation method for a clutch system according to the present invention, in step S4, ultrasonic cleaning is performed at room temperature, the cleaning medium is deionized water, the cleaning time is 5-10 minutes, and hot air drying is performed after cleaning.

[0024] As a preferred embodiment of the Y-ring preparation method for the clutch system of the present invention, the self-lubricating layer formed in situ is a PTFE dry film chemically bonded to the compound rubber B matrix, with a film thickness of 5-10 μm.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1. This invention utilizes a dual-formulation system, with customized formulations for the working conditions of the Y-ring root and lip respectively. The root formulation achieves high rigidity and high extrusion resistance, while the lip formulation achieves high elasticity and low friction. Simultaneously, the two rubber materials are molecularly bonded through viscous flow hot melt co-extrusion, with no obvious interface, thus avoiding the risk of delamination and cracking in the bonding composite process.

[0027] 2. This invention adopts a dual-formula integrated co-extrusion near-net-shape preforming, combined with a zoned temperature-controlled mold that avoids the parting lip, to achieve precision molding without flash or parting lines. It completely eliminates the trimming process in existing processes, avoiding damage to the sealing lip from the source. The product yield rate is increased from 85%-90% in the industry to over 99.5%, while significantly shortening the production process to improve production efficiency.

[0028] 3. This invention utilizes an in-mold gradient heating directional vulcanization process, combined with the vulcanization temperature difference between two vulcanization systems, to precisely control the crosslinking density in different regions, achieving a gradient structure with high crosslinking and high rigidity at the root and low crosslinking and high elasticity at the lip. Simultaneously, a self-lubricating layer is formed through in-situ chemical bonding during vulcanization, forming an integrated chemical bond with the rubber matrix, eliminating the risk of detachment and reducing the coefficient of friction, thereby improving wear resistance and lifespan. This solves the problem of easy coating detachment in existing secondary coating processes.

[0029] 4. This invention applies ultrasonic-assisted vibration throughout the vulcanization process, which can effectively eliminate internal stress during vulcanization, improve the uniformity of crosslinking of the rubber compound, remove internal micro-bubbles, and significantly improve the long-term sealing stability and resilience of the product.

[0030] 5. The raw materials and equipment used in this invention are all mature and common equipment in the rubber industry. Only custom-made die and mold are required. There are no special non-standard equipment or scarce materials. The equipment investment cost is low and the changeover is flexible. It can be adapted to the mass production of millions of OEMs and can also quickly switch to non-standard specifications. It has a strong industrialization capability and practical value. Attached Figure Description

[0031] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0032] Figure 1 This is a schematic diagram of the preparation process structure of the present invention. Detailed Implementation

[0033] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] The Y-rings for clutch system master cylinders prepared in the embodiments and comparative examples of this invention are both φ25.4mm and 3.2mm in cross-sectional width. The testing standards adopted are the current national standards for rubber seals, and the bench tests are conducted using a special simulation test bench for automotive clutch master cylinders.

[0035] Example 1

[0036] This embodiment describes a method for preparing the Y-ring of a conventional clutch system for passenger vehicles. The specific steps are as follows:

[0037] S1 dual-formula mixing:

[0038] Compound A (root-specific) formulation (parts by weight): 100 parts of nitrile rubber with 34% acrylonitrile content, 45 parts of high abrasion-resistant carbon black N330, 10 parts of fumed silica, 2.5 parts of DCP, 1.5 parts of TAIC, 1 part of antioxidant RD, 1 part of antioxidant 4010NA, and 5 parts of DOS.

[0039] Mixing process: Put the raw rubber into an internal mixer and plasticize it at 80°C for 3 minutes. Then add the antioxidant, reinforcing agent and plasticizer in sequence. Heat the mixture to 110°C and mix for 8 minutes. Discharge the rubber into sheets and cool it to room temperature. Let it stand for 12 hours. Then put it into an open mill and add the vulcanizing agent and crosslinking agent below 45°C. Pass the mixture through a thin mill 6 times and mix it in a triangular bag. Filter the rubber through a 120-mesh filter to obtain compound rubber A. Let it stand at room temperature for later use.

[0040] Compound B (for lip edge use) formulation (parts by weight): 100 parts of nitrile rubber with 33% acrylonitrile content, 25 parts of fast-extrusion carbon black N550, 5 parts of nano montmorillonite, 0.8 parts of sulfur, 1.2 parts of accelerator CZ, 0.3 parts of accelerator TMTD, 8 parts of PTFE grafted maleic anhydride modifier, 1 part of antioxidant MB, 1 part of antioxidant 4020, 6 parts of DOA, and 0.5 parts of calcium stearate;

[0041] Mixing process: Put the raw rubber into an internal mixer and plasticize at 75°C for 4 minutes. Then add antioxidant, reinforcing agent, plasticizer, and PTFE graft modifier in sequence. Heat to 105°C and mix for 7 minutes. Discharge the rubber into sheets and cool to room temperature. Let it stand for 12 hours. Then put it into an open mill and add vulcanizing agent and accelerator below 40°C. Pass through a thin mill 8 times and mix thoroughly in a triangular bag. Filter the rubber through a 150-mesh filter to obtain compound rubber B. Let it stand at room temperature for later use.

[0042] S2 Dual-Formula Integrated Co-Extrusion Preform

[0043] The system employs a twin-screw co-extrusion unit, equipped with two independent feeding hoppers, a temperature-controlled screw system, and a Y-shaped co-extrusion die. The A-grade feed chamber of the die corresponds to the root of the Y-ring, while the B-grade feed chamber corresponds to the lip of the Y-ring. The A-grade screw is set to a temperature of 55℃ and a speed of 15 rpm; the B-grade screw is set to a temperature of 50℃ and a speed of 10 rpm. The traction speed is linked to the screw speed, and the strip size is controlled in real-time using a laser diameter gauge in a closed-loop manner, resulting in an integrated, irregularly shaped strip with a cross-sectional dimensional tolerance within ±0.03 mm. The strip is then precisely cut into a fixed-weight annular preform according to the designed circumference, with a single preform weight error within ±0.02 g. The cut ends are then beveled at a 45° angle.

[0044] S3 In-mold Gradient Temperature Directed Vulcanization

[0045] A zoned temperature-controlled alloy steel mold is used, with the parting surface located on the non-sealed surface at the root of the Y-ring. It incorporates two independent temperature control systems and an ultrasonic transducer. The mold is preheated, with the root temperature control zone preheated to 170℃ and the lip temperature control zone preheated to 120℃. The annular preform is precisely placed into the cavity, and the clamping pressure is stabilized at 15MPa after mold closing. A first-stage directional vulcanization process is performed, followed by constant temperature and pressure vulcanization for 5 minutes, while simultaneously activating the ultrasonic auxiliary device with an ultrasonic frequency of 20kHz and a power density of 0.5W / cm³. 2 After the first vulcanization is completed, maintain the clamping pressure and ultrasonic vibration to rapidly raise the temperature control zone of the lip to 150°C, and vulcanize under constant temperature and pressure for 3 minutes; after vulcanization, introduce circulating cooling water to rapidly cool down to below 40°C, open the mold and remove the semi-finished product.

[0046] S4 gradient two-stage post-vulcanization and finished product processing

[0047] The semi-finished product is placed in a programmable hot air circulating oven, protected by nitrogen. It is first kept at 100℃ for 2 hours, and then heated to 120℃ for 2 hours to complete the gradient two-stage vulcanization. The product is then placed in an ultrasonic cleaner, cleaned with deionized water at room temperature for 5 minutes, and dried with hot air. After full inspection of appearance, size, and performance, the finished product is obtained.

[0048] Example 2

[0049] This embodiment describes a method for preparing a Y-ring for a low-friction clutch system in a high-end passenger vehicle. The specific steps are as follows:

[0050] S1 dual-formula mixing

[0051] Compound A (root-specific) formulation (parts by weight): 100 parts of nitrile rubber with 36% acrylonitrile content, 50 parts of high abrasion-resistant carbon black N330, 12 parts of fumed silica, 3 parts of DCP, 1.8 parts of TAIC, 1.5 parts of antioxidant RD, 1.2 parts of antioxidant 4010NA, and 6 parts of DOS.

[0052] Mixing process: Same as in Example 1;

[0053] Compound B (for lip edge use) formulation (parts by weight): 100 parts of nitrile rubber with 29% acrylonitrile content, 30 parts of fast-extrusion carbon black N550, 6 parts of nano montmorillonite, 1 part of sulfur, 1.5 parts of accelerator CZ, 0.4 parts of accelerator TMTD, 10 parts of PTFE grafted maleic anhydride modifier, 1.2 parts of antioxidant MB, 1.2 parts of antioxidant 4020, 7 parts of DOA, and 0.8 parts of calcium stearate;

[0054] Mixing process: Same as in Example 1;

[0055] S2 Dual-Formula Integrated Co-Extrusion Preform

[0056] The screw temperature control for compound A is set at 60℃ and the screw speed at 18 rpm; the screw temperature control for compound B is set at 55℃ and the screw speed at 12 rpm; the remaining process parameters are the same as in Example 1.

[0057] S3 In-mold Gradient Temperature Directed Vulcanization

[0058] Mold preheating temperature: 175℃ for the root temperature control zone, 125℃ for the lip temperature control zone; clamping pressure: 18MPa; first-stage vulcanization time: 6min; ultrasonic frequency: 25kHz, power density: 0.6W / cm³ 2 The temperature control zone of the second-stage vulcanization lip is raised to 155°C, and the vulcanization time is 4 minutes; the remaining process parameters are the same as in Example 1.

[0059] S4 gradient two-stage post-vulcanization and finished product processing

[0060] The process parameters are the same as in Example 1, and the finished product is obtained.

[0061] Example 3

[0062] This embodiment describes a method for preparing the Y-ring of a heavy-duty clutch system for commercial vehicles. The specific steps are as follows:

[0063] S1 dual-formula mixing

[0064] Compound A (root-specific) formulation (parts by weight): 100 parts of nitrile rubber with 40% acrylonitrile content, 55 parts of high abrasion-resistant carbon black N330, 15 parts of fumed silica, 3.5 parts of DCP, 2 parts of TAIC, 2 parts of antioxidant RD, 1.5 parts of antioxidant 4010NA, and 8 parts of DOS.

[0065] Mixing process: Same as in Example 1;

[0066] Compound B (for lip edge use) formulation (parts by weight): 100 parts of nitrile rubber with 26% acrylonitrile content, 35 parts of fast-extrusion carbon black N550, 8 parts of nano montmorillonite, 1.2 parts of sulfur, 1.8 parts of accelerator CZ, 0.5 parts of accelerator TMTD, 12 parts of PTFE grafted maleic anhydride modifier, 1.5 parts of antioxidant MB, 1.5 parts of antioxidant 4020, 9 parts of DOA, and 1 part of calcium stearate;

[0067] Mixing process: Same as in Example 1;

[0068] S2 Dual-Formula Integrated Co-Extrusion Preform

[0069] The temperature control of the screw for compound A is set at 65℃ and the rotation speed at 20 rpm; the temperature control of the screw for compound B is set at 60℃ and the rotation speed at 15 rpm; the remaining process parameters are the same as in Example 1.

[0070] S3 In-mold Gradient Temperature Directed Vulcanization

[0071] Mold preheating temperature: 180℃ for the root temperature control zone, 130℃ for the lip temperature control zone; clamping pressure: 20MPa; first-stage vulcanization time: 8min; ultrasonic frequency: 30kHz, power density: 0.8W / cm³ 2 The temperature control zone of the second-stage vulcanization lip is raised to 160°C, and the vulcanization time is 5 minutes; the remaining process parameters are the same as in Example 1.

[0072] S4 gradient two-stage post-vulcanization and finished product processing

[0073] The process parameters are the same as in Example 1, and the finished product is obtained.

[0074] Comparative Example

[0075] This comparative example shows a Y-ring of the same specification prepared by conventional compression molding process using existing technology. The specific steps are as follows:

[0076] S1 Single Formula Mixing

[0077] Formula (parts by weight): 100 parts of nitrile rubber with 33% acrylonitrile content, 40 parts of high abrasion-resistant carbon black N330, 1.5 parts of sulfur, 2 parts of accelerator CZ, 1.5 parts of antioxidant RD, 1.5 parts of antioxidant 4010NA, 7 parts of DOS, and 1 part of stearic acid.

[0078] Mixing process: Conventional internal mixing + open mill two-stage mixing process, filter out the glue through a 120-mesh filter to obtain the mixed glue, and let it stand at room temperature for later use.

[0079] S2 Preforming

[0080] The compounded rubber is extruded into round rubber strips through an extruder and cut into fixed-weight rubber blanks to obtain preforms;

[0081] S3 Compression Vulcanization

[0082] Using a conventional Y-ring mold, the mold is preheated to 160℃. The rubber blank is placed into the cavity, and after the mold is closed, the mold pressure is 15MPa. The mold is vulcanized at a constant temperature for 12 minutes. The mold is then opened and the semi-finished product with flash is taken out.

[0083] S4 Post-processing

[0084] The semi-finished product is placed in a freeze trimming machine for freeze trimming to remove the lip edge flash; then a PTFE lubricating coating is applied to the lip surface through a spraying process and dried and cured; then it is placed in an oven and vulcanized at a constant temperature of 120℃ for 4 hours; after cleaning and testing, the finished product is obtained.

[0085] The Y-rings prepared in Examples 1-3 and the comparative example were subjected to performance tests according to relevant national standards. Simulated bench life tests and batch yield statistics were also conducted. The test results are shown in the table below:

[0086] The test data clearly shows that the Y-ring prepared in this embodiment of the invention has the following significant advantages compared with the prior art:

[0087] 1. The performance gradient is precisely controllable, with root tensile strength increased by 37%-53% and extrusion resistance significantly enhanced, which can solve the problem of root collapse and deformation under high pressure; the lip elongation at break is increased by 19%-41%, and the resilience performance is significantly optimized, ensuring the reliability of dynamic sealing.

[0088] 2. Compression set is reduced by 47%-52%, and the rebound stability and sealing performance after long-term use are greatly improved, which can solve the pain points of soft clutch pedal and excessive free travel.

[0089] 3. It has superior resistance to brake fluid and a smaller volume change rate, fully meeting the stringent requirements for safety components in automotive clutch systems.

[0090] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a Y-ring for a clutch system, characterized in that, Includes the following steps: S1. Functional dual-formulation compounding: High-rigidity anti-extrusion compound A for the root of the Y-ring and high-elasticity low-friction self-lubricating compound B for the lip of the Y-ring are prepared separately; compound A adopts a peroxide vulcanization system and compound B adopts a sulfur vulcanization system, and the vulcanization initiation temperature of compound B is lower than that of compound A. S2. Dual-formula integrated co-extrusion preforming: Compound A and compound B are co-extruded in a viscous flow state through a twin-screw co-extrusion equipment and a shaped co-extrusion die to obtain an integrated shaped rubber strip that perfectly matches the cross-section of the Y-ring. After cutting, an annular preform is obtained. The shaped co-extrusion die is equipped with independent A rubber feeding chamber and B rubber feeding chamber, which correspond to the root area and lip area of ​​the Y-ring, respectively. S3. In-mold gradient heating directional vulcanization: The annular preform is placed in a zoned temperature-controlled mold. After the mold is closed, the root area is first subjected to a directional vulcanization to allow the compound A to complete the main cross-linking. The lip area is then subjected to a second-stage vulcanization process by raising the temperature, which enables the compound B to complete full cross-linking and forms a chemically bonded self-lubricating layer in situ on the lip surface. Ultrasonic-assisted vibration is applied throughout the vulcanization process. S4. Gradient two-stage post-vulcanization and finished product processing: The vulcanized semi-finished product undergoes gradient temperature two-stage post-vulcanization, and after cleaning and testing, the finished product is obtained.

2. The method for preparing the Y-ring of the clutch system according to claim 1, characterized in that: By weight, the formulation of compound A is as follows: 100 parts of high acrylonitrile content nitrile rubber, 55-70 parts of composite reinforcing agent, 2.5-3.5 parts of peroxide vulcanizing agent, 1.5-2 parts of crosslinking agent, 2-3.5 parts of composite antioxidant, and 5-8 parts of extract-resistant plasticizer; the acrylonitrile content of the high acrylonitrile content nitrile rubber is 34%-40% by weight.

3. The method for preparing the Y-ring of the clutch system according to claim 1, characterized in that: By weight, the formulation of compound B is as follows: 100 parts of medium acrylonitrile-content nitrile rubber, 30-43 parts of low-reinforcing filler system, 2.3-3.5 parts of sulfur vulcanization system, 8-12 parts of PTFE-grafted maleic anhydride modifier, 2-3 parts of composite antioxidant, 6-9 parts of low-temperature resistant plasticizer, and 0.5-1 parts of internal lubricant; the acrylonitrile mass fraction of the medium acrylonitrile-content nitrile rubber is 26%-33%.

4. The method for preparing the Y-ring of the clutch system according to claim 1, characterized in that: In S2, the twin-screw co-extrusion equipment is equipped with two independent feeding systems and temperature control systems. The extrusion temperature control temperature of compound A is 55-65℃, and the extrusion temperature control temperature of compound B is 50-60℃. The cross-sectional dimensional tolerance of the shaped rubber strip is controlled within ±0.03mm, and the single-piece weight error of the annular preform is controlled within ±0.02g.

5. The method for preparing the Y-ring of the clutch system according to claim 1, characterized in that: In S3, the zoned temperature control mold has two sets of independently controlled heating systems, corresponding to the root temperature control zone and the lip temperature control zone respectively. The mold parting surface is set on the non-sealing surface at the root of the Y-ring, completely avoiding the sealing lip area.

6. The method for preparing the Y-ring of the clutch system according to claim 1, characterized in that: In S3, the process parameters for the first stage of directional vulcanization are: root temperature control zone temperature 170-180℃, lip temperature control zone temperature 120-130℃, clamping pressure 15-20MPa, and vulcanization time 5-8min; the process parameters for the second stage of vulcanization are: lip temperature control zone temperature raised to 150-160℃, constant temperature vulcanization time 3-5min, and clamping pressure kept constant throughout the process.

7. The method for preparing the Y-ring of the clutch system according to claim 1, characterized in that: In step S3, the process parameters for ultrasonic-assisted vibration are: ultrasonic frequency 20-30kHz, power density 0.5-0.8W / cm². 2 The vibration continues throughout the entire vulcanization process.

8. The method for preparing the Y-ring of the clutch system according to claim 1, characterized in that: In S4, the gradient two-stage post-vulcanization process is as follows: first, heat at 100°C for 2 hours, then heat to 120°C and heat for 2 hours, with nitrogen protection throughout the process.

9. The method for preparing the Y-ring of the clutch system according to claim 1, characterized in that: In step S4, ultrasonic cleaning at room temperature is used, the cleaning medium is deionized water, the cleaning time is 5-10 minutes, and hot air drying is performed after cleaning.

10. The method for preparing the Y-ring of the clutch system according to claim 1, characterized in that: The self-lubricating layer formed in situ is a PTFE dry film chemically bonded to the matrix of compound B, with a film thickness of 5-10 μm.

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