Processes for improving the quality of crane tires

Abstract

This invention discloses a process for improving the quality of crane-specific tires, relating to the field of tire technology. The invention identifies and standardizes key process parameters throughout the entire tire forming process, including tire blank pressing, X-ray inspection, tire blank shaping, forming drum rotation, and pressure roller condition detection. It also standardizes indicators such as tire carcass expansion coefficient, inflation pressure, and time, fundamentally preventing defects such as unstable tire carcass stretching and steel wire retraction deformation, improving the stability of steel wire distribution in the tire carcass, significantly increasing the tire's X-ray deformation pass rate and durability, and adapting to the harsh operating conditions required by cranes.

Description

Technical Field

[0001] This invention relates to the field of tire technology, and more specifically to a process for improving the quality of crane tires. Background Technology

[0002] As heavy engineering machinery, cranes are often used in complex and harsh environments such as ports, construction sites, and mines. This places extremely high demands on the load-bearing capacity, structural stability, durability, and deformation resistance of specialized tires. The quality of the tires directly determines the crane's operational safety, efficiency, and stability.

[0003] Currently, in the manufacturing of crane tires, the molding process, as the core link in tire structure formation, lacks a systematic and standardized management system for identifying key process parameters related to tire carcass stretching, steel wire positioning, and pressing operations. This results in crane tires commonly exhibiting quality problems such as poor consistency in the steel wire distribution curve, high deformation rate of the tire shoulder steel wires, and uncontrolled tire carcass pullback. These issues not only lead to low X-ray deformation pass rates but also significantly reduce the actual durability of the tires, making them prone to early bulges, delamination, and blowouts. This increases safety hazards for crane operations and raises equipment maintenance costs in construction projects. Therefore, it is urgent to establish a standardized molding process for crane tires to achieve precise control over key parameters during the molding process, thereby addressing the quality defects of existing tires at their root. Summary of the Invention

[0004] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art, provide a process to improve the quality of crane tires, identify and standardize the key process parameters in the tire forming process, avoid quality defects such as unstable tire body stretching and uncontrolled steel wire pullback during the tire forming process, improve the stability and conformity of the distribution curve of the tire body steel wire in the tire, improve the X-ray deformation pass rate, and improve the durability of the product.

[0005] The technical solution of this invention is as follows:

[0006] Processes to improve the quality of crane tires:

[0007] (1) During the molding process, the rolling direction of the tire blank when the sidewall, tread assembly and wire ring assembly are pressed is calibrated and recorded. Then the tire blank is vulcanized and tracked by X-ray inspection. During the X-ray inspection, an arrow-shaped metal piece is fixed on the tire crown. The arrow points in the same direction as the rolling direction when the tire blank is pressed. Then the tire is inspected. The direction of the arrow-shaped metal piece will be displayed on the X-ray image. Based on the direction of the arrow-shaped metal piece in the X-ray image and the deformation direction of the tire carcass wire, the correlation between the deformation direction of the tire carcass wire and the rolling direction of the tire blank when pressed is determined.

[0008] (2) Before the finished tire is inspected, three steel wires perpendicular to the center of the tire crown are attached to the tire body in the tire body direction. The length of the steel wires covers the tire crown and the area under both shoulders. The three steel wires are distributed in parallel at an angle of 90° to 120° in the tire body. Then X-ray inspection is performed. Based on the distribution trend of the steel wires and the tire body steel wires in the tire shoulder area in the X-ray image, the number of deformed tire body steel wires in the tire shoulder area can be accurately determined.

[0009] (3) During fast charging, the fast charging pressure is set to 0.3~0.4MPa and the fast charging time is 4~15s. After fast charging, the inflation pressure is switched to 0.1~0.12MPa and maintained. Then, the tire blank is shaped. When the forming locking block supports the tire, the time difference between the left and right sides is required to be ≤1s, and the pressure difference between the left and right forming locking blocks is ≤0.02MPa. The standard pressure of the single forming locking block is 0.75~0.85MPa, and the medium pressure of the forming internal pressure is 0.1~0.12MPa. The tire body expansion coefficient X = the length of the tire body between the steel rings of the finished tire section B ÷ the width of the forming plane C = 1.028~1.041. This step calibrates and standardizes the fast charging pressure, fast charging time, and time difference of the forming locking block support to avoid the tire body outside the steel ring from shifting to the inside of the steel ring due to excessive pressure. This displacement will cause the tire body steel wire bending to increase during X-ray inspection, resulting in product defects.

[0010] (4) The rolling direction of the formed tire blank parts during the pressing process is calibrated and recorded. When the tire tread is pressed after shaping, the forming drum rotates counterclockwise. When the lower rubber core and the reverse tire side are pressed, the forming drum rotates counterclockwise or clockwise. This step can avoid the problem of the tire body steel wires being obliquely deformed due to the pressure during the pressing process.

[0011] (5) After the tread and sidewall components are pressed together, record the actual number of rotations of the pressure rollers on the left and right sides of the molding machine. Both rollers should be greater than 5 rotations. This step can effectively confirm the condition of the pressure rollers and avoid complete deformation of the tire body due to the sensitivity of the pressure roller rotation.

[0012] Preferably, in step (1), the arrow-shaped metal sheet is made of iron or aluminum.

[0013] Preferably, in step (2), the diameter of the steel wire is 0.8 to 1.5 times the diameter of the carcass steel wire.

[0014] Preferably, in step (3), the method for measuring the length B of the tire body between the steel wire rings of the finished tire section is as follows: after the tire blank is formed and vulcanized, the finished section is cut, the section is polished, and then the length of the tire body between the steel wire rings of the tire is measured by a tape measure, which is the length B of the tire body between the steel wire rings of the finished tire section.

[0015] Preferably, in step (5), a mark is affixed to the side of the left and right pressure rollers of the molding machine, and the actual number of rotations of the left and right pressure rollers is recorded based on the number of rotations of the mark.

[0016] The process for improving the quality of crane tires disclosed in this invention solves the industry pain points in existing crane tire production, such as unstable tire carcass stretching, uncontrolled steel wire pullback and deformation, and low detection accuracy, by accurately identifying, standardizing, and strictly controlling key process parameters throughout the tire forming process. Compared with existing technologies, it has the following significant advantages:

[0017] 1. This invention calibrates and records the rolling direction during tire blank pressing, and achieves visual traceability of the rolling direction through an arrow-shaped metal piece during X-ray inspection. It can accurately determine the correlation between the deformation of the tire body steel wire and the pressing operation direction, breaking the dilemma of no trace of quality problems in existing production, greatly improving the efficiency of analysis and rectification of quality defects in the molding process, and providing accurate data support for process optimization.

[0018] 2. This invention attaches auxiliary steel wires before X-ray inspection of finished tires. Using these steel wires as a reference, the number of deformed steel wires in the tire shoulder area can be accurately determined. This solves the problems of vague judgment and inaccurate data in traditional X-ray inspection of tire shoulder steel wire deformation, significantly improves the accuracy of inspection results, effectively reduces the rate of missed detection and misjudgment of quality defects, and builds a solid inspection defense line for the quality control of finished tires.

[0019] 3. This invention standardizes the pressure and time parameters for fast charging and medium pressure, sets strict limits on the time difference and pressure difference of the forming locking blocks, and limits the reasonable range of the tire carcass expansion coefficient. This achieves uniform and controllable stretching of the tire carcass during the tire blank shaping process, avoiding excessive or insufficient local stretching of the tire carcass caused by pressure fluctuations and inconsistent operation of the forming locking blocks. At the same time, the rotation direction of the forming drum is uniformly calibrated, eliminating the problems of excessive tire carcass wire pullback and oblique deformation caused by pressing pressure from the operational level, and significantly improving the stability and conformity of the distribution curve of tire carcass wires in the tire.

[0020] 4. By quantitatively detecting and setting limits on the number of free rotations of the rear pressure roller and the actual number of idle rotations of the left and right pressure rollers, this invention can quickly and intuitively determine the rotational sensitivity of the pressure rollers, promptly detect equipment problems such as pressure roller jamming and inflexible rotation, avoid tire body deformation caused by abnormal equipment conditions, and achieve linkage control between equipment conditions and process quality, thus ensuring the stability of tire molding quality from the production equipment level.

[0021] 5. This invention, through multi-dimensional and full-process standardized process control, effectively reduces the amount of tire carcass retraction and the number of deformed steel wires in the tire carcass, significantly improving the X-ray deformation qualification rate of finished tires. At the same time, the stability of the steel wire distribution and the uniformity of the tire carcass structure are greatly improved, directly enhancing the durability of crane-specific tires. This effectively reduces the occurrence of early bulges, delamination, and blowouts during tire use, and improves the tire's load-bearing capacity and deformation resistance, making it suitable for the use of cranes in harsh operating environments such as ports, mines, and construction sites.

[0022] 6. This invention establishes a complete standardized management system for the forming process of crane-specific tires. It clearly defines and calibrates the key parameters of each link, such as forming, testing, and equipment control, changing the current situation of vague process parameters and inconsistent operations in production. This not only improves the production efficiency and product quality consistency of the enterprise, but also provides a reference for the standardization and normalization of the crane-specific tire industry, promoting the overall improvement of production quality and technology level in the industry. Detailed Implementation

[0023] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention.

[0024] Example 1

[0025] This embodiment uses a 325 / 95R24 tire as an example to provide a process for improving the quality of crane-specific tires:

[0026] (1) During the molding process, the rolling direction of the tire blank when the sidewall, tread assembly and wire ring assembly are pressed is calibrated and recorded. Then the tire blank is vulcanized and tracked by X-ray inspection. During the X-ray inspection, an aluminum arrow-shaped metal piece is fixed on the tire crown. The arrow points in the same direction as the rolling direction when the tire blank is pressed. Then the tire is inspected and the direction of the arrow-shaped metal piece will be displayed on the X-ray image.

[0027] (2) Before the finished tire is inspected, three steel wires perpendicular to the center of the tire crown are attached to the tire body in the tire body direction. The diameter of the steel wires is 0.8 times the diameter of the tire body steel wires. The steel wires are attached to cover the tire crown and the area under both shoulders. The three steel wires are distributed in parallel at 90° intervals in the tire body. Then X-ray inspection is performed.

[0028] (3) During fast charging, the fast charging pressure is set to 0.3MPa and the fast charging time is 4s. After fast charging, the inflation pressure is switched to 0.1MPa and maintained. Then, the tire blank is shaped. When the forming locking block supports the tire, the time difference between the left and right sides is 0s, and the pressure difference between the left and right forming locking blocks is 0MPa. The standard pressure of the single forming locking block is 0.75MPa, and the medium pressure of the forming internal pressure is 0.1MPa. The tire body expansion coefficient X = the length of the tire body between the steel rims of the finished tire section B ÷ the width of the forming plane C = 759mm ÷ 730mm = 1.04.

[0029] (4) The rolling direction of the molded tire blank components during the pressing process is calibrated and recorded. When the tire tread is pressed after shaping, the forming drum rotates counterclockwise. When the lower rubber core and the reverse tire side are pressed, the forming drum rotates counterclockwise.

[0030] (5) A note is attached to the side of the left and right pressure rollers of the molding machine as a marker. After the tire tread and tire sidewall components are pressed according to the process steps, the actual number of idle rotations of the left and right pressure rollers of the molding machine is recorded according to the number of rotations of the note. The number of idle rotations of the left tire side pressure roller is 6, the number of idle rotations of the right tire side pressure roller is 8, the number of idle rotations of the left tire tread pressure roller is 8, and the number of idle rotations of the right tire tread pressure roller is 7, all of which are greater than 5.

[0031] Comparative Example 1

[0032] Without performing the operations of Example 1, tires of specification 325 / 95R24 are produced according to existing processes.

[0033] The tire performance of Examples 1 and 1 (Comparative Example) was tested. The tire carcass retraction amount is the tire carcass expansion coefficient X, which is considered acceptable within the range of 1.028-1.041. The test method for the number of deformed steel wires in the tire carcass is as follows: After X-ray inspection, the tire carcass steel wires intersect with three steel wires perpendicular to the center of the tire crown. The maximum number of intersections between the tire carcass steel wires and the three steel wires within a 50-150mm range on the tire shoulder in the X-ray image is taken as the number of deformed steel wires in the tire carcass. The X-ray deformation pass rate of the tire is calculated based on the number of deformed steel wires. A tire is considered acceptable if the number of deformed steel wires is ≤3, otherwise it is considered unacceptable; the required X-ray deformation pass rate is ≥99.90%. The durability test method is as follows: run at a speed of 55 km / h, first run at 65% load for 7 hours, then at 85% load for 16 hours, then at 100% load for 24 hours, and then increase the load by 10% every 10 hours until the tire is damaged; the durability performance is required to be >90 hours.

[0034] The test results are shown in Table 1:

[0035] Table 1. Tire performance test results of Example 1 and Comparative Example 1

[0036]

[0037] Example 2

[0038] This embodiment uses a 315 / 80R22.5 tire as an example to provide a process for improving the quality of crane-specific tires:

[0039] (1) During the molding process, the rolling direction of the tire blank when the sidewall, tread assembly and wire ring assembly are pressed is calibrated and recorded. Then the tire blank is vulcanized and tracked by X-ray inspection. During the X-ray inspection, an iron arrow-shaped metal piece is fixed on the tire crown. The arrow points in the same direction as the rolling direction when the tire blank is pressed. Then the tire is inspected and the direction of the arrow-shaped metal piece will be displayed on the X-ray image.

[0040] (2) Before the finished tire is inspected, three steel wires perpendicular to the center of the tire crown are attached to the tire body in the tire body direction. The diameter of the steel wires is 1.5 times the diameter of the tire body steel wires. The steel wires are attached to cover the tire crown and the area under both shoulders. The three steel wires are distributed in parallel at 120° intervals in the tire body. Then X-ray inspection is performed.

[0041] (3) During fast charging, the fast charging pressure is set to 0.4MPa and the fast charging time is 15s. After fast charging, the internal pressure is switched to 0.12MPa and maintained. Then, the tire blank is shaped. When the forming locking block supports the tire, the time difference between the left and right sides is 0s, and the pressure difference between the left and right forming locking blocks is 0.02MPa. The standard pressure of the single forming locking block is 0.85MPa, and the medium pressure of the forming internal pressure is 0.12MPa. The tire body expansion coefficient X = the length of the tire body between the steel rims of the finished tire section B ÷ the width of the forming plane C = 749mm ÷ 722mm = 1.037.

[0042] (4) The rolling direction of the molded tire blank components during the pressing process is calibrated and recorded. When the tire tread is pressed after shaping, the forming drum rotates counterclockwise. When the lower rubber core and the reverse tire side are pressed, the forming drum rotates clockwise.

[0043] (5) A note is attached to the side of the left and right pressure rollers of the molding machine as a marker. After the tire tread and tire sidewall components are pressed according to the process steps, the actual number of idle rotations of the left and right pressure rollers of the molding machine is recorded according to the number of rotations of the note. The number of idle rotations of the left tire side pressure roller is 8, the number of idle rotations of the right tire side pressure roller is 8, the number of idle rotations of the left tire tread pressure roller is 6, and the number of idle rotations of the right tire tread pressure roller is 6, all of which are greater than 5.

[0044] Comparative Example 2

[0045] Without performing the operations of Example 2, tires of specification 315 / 80R22.5 are produced according to the existing process.

[0046] The tire performance of Example 2 and Comparative Example 2 was tested, and the test results are shown in Table 2:

[0047] Table 2. Tire performance test results of Example 2 and Comparative Example 2

[0048]

[0049] As can be seen from Examples 1-2 and Comparative Examples 1-2, the present invention identifies and standardizes the key process parameters in the tire forming process, avoiding quality defects such as unstable tire body stretching and uncontrolled steel wire pullback during the tire forming process, improving the stability and conformity of the distribution curve of the tire body steel wire in the tire, improving the X-ray deformation pass rate, and improving the durability of the product.

Claims

1. A process for improving the quality of crane-specific tires, characterized in that, (1) During the molding process, the rolling direction of the tire blank when the sidewall, tread assembly and wire ring assembly are pressed is calibrated and recorded. Then the tire blank is vulcanized and tracked by X-ray inspection. During the X-ray inspection, an arrow-shaped metal piece is fixed on the tire crown, and the arrow points in the same direction as the rolling direction when the tire blank is pressed. (2) Before the finished tire is inspected, three steel wires perpendicular to the center of the tire crown are attached to the tire body in the tire body direction. The length of the steel wires covers the tire crown and the area under the shoulders. The three steel wires are distributed in parallel at an angle of 90°~120° in the tire body. Then X-ray inspection is carried out. (3) During fast charging, the fast charging pressure is set to 0.3~0.4MPa and the fast charging time is 4~15s. After fast charging, the inflation pressure is switched to 0.1~0.12MPa and maintained. Then, the tire blank is shaped. When the forming locking block supports the tire, the time difference between the left and right sides is required to be ≤1s, and the pressure difference between the left and right forming locking blocks is ≤0.02MPa. The standard pressure of the single forming locking block is 0.75~0.85MPa, and the medium pressure of the forming internal pressure is 0.1~0.12MPa. The tire body expansion coefficient X = the length of the tire body between the steel rings of the finished tire section B ÷ the width of the forming plane C = 1.028~1.

041. (4) The rolling direction of the molded tire blank components during the pressing process is calibrated and recorded. When the tire tread is pressed after shaping, the forming drum rotates counterclockwise. When the lower rubber core and the reverse tire side are pressed, the forming drum rotates counterclockwise or clockwise. (5) After the tread and sidewall components are pressed together, record the actual number of rotations of the pressure rollers on the left and right sides of the molding machine. They should all be greater than 5 rotations.

2. The process for improving the quality of crane-specific tires as described in claim 1, characterized in that, In step (1), the arrow-shaped metal sheet is made of iron or aluminum.

3. The process for improving the quality of crane-specific tires as described in claim 1, characterized in that, In step (2), the diameter of the steel wire is 0.8 to 1.5 times the diameter of the carcass steel wire.

4. The process for improving the quality of crane-specific tires as described in claim 1, characterized in that, In step (3), the method for measuring the length B of the tire body between the steel wire rings in the finished tire section is as follows: After the tire blank is formed and vulcanized, the finished section is cut, the section is polished, and then the length of the tire body between the steel wire rings is measured, which is the length B of the tire body between the steel wire rings in the finished tire section.

5. The process for improving the quality of crane-specific tires as described in claim 1, characterized in that, In step (5), a mark is attached to the side of the left and right pressure rollers of the molding machine. When recording the actual number of rotations of the left and right pressure rollers, the number of rotations of the mark shall be used as the standard.

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