Electric automobile tire with high-modulus polyester tire body cord

Abstract

The invention relates to the technical field of tire manufacturing, and discloses an electric vehicle tire of a high-modulus polyester tire body cord thread, by adopting the polyester cord thread with a specific parameter combination (low constant load elongation and low dry heat shrinkage rate) and controlling the elongation rate of the cord thread at a forming drum, the bearing potential of a tire body is directly maximized, and the tire body is not damaged. Therefore, the manufactured tire can meet the requirement of the electric automobile for high bearing capacity, and meanwhile, the tire has low rolling resistance and good maneuvering performance. The reinforced tire body can be used for building a firmer skeleton for the tire, so that stronger lateral support can be provided during high-speed steering, the deformation of the tire wall is effectively inhibited, and the control stability and the safety limit of a vehicle are synchronously improved.

Description

Technical Field

[0001] This invention relates to the field of tire manufacturing technology, and more specifically, to an electric vehicle tire with high-modulus polyester carcass cord. Background Technology

[0002] As the global automotive industry moves towards electrification and intelligentization, the electric vehicle market is experiencing explosive growth. In this wave of transformation, the specialized research and development of key components has become the focus of industry competition, and its importance is increasingly prominent. As the only medium of contact between the vehicle and the road, tire performance directly determines the ultimate experience of an electric vehicle, making technological innovation in tires particularly urgent.

[0003] Compared to traditional internal combustion engine vehicles, electric vehicles, due to their large battery packs, generally have a curb weight increase of about 10% to 20%, and some models even more. This structural change first poses a severe challenge to the load-bearing capacity and durability of tires. Tires must have higher load indices and stronger carcass structures to withstand greater static loads and more severe dynamic impacts.

[0004] At the same time, the powertrain characteristics of electric vehicles impose unique driving demands. The instantaneous release of peak torque by the electric motor requires tires to provide exceptional grip during start-up and acceleration to prevent slippage and ensure efficient power transmission. Furthermore, the heavier vehicle body generates greater centrifugal force and inertia during high-speed cornering or emergency lane changes. This necessitates extremely rigid tire treads and sidewalls to minimize deformation, thereby providing users with precise steering feedback and robust driving stability, ensuring safety.

[0005] Beyond performance and safety, energy efficiency is another core issue for electric vehicles. Tire rolling resistance is a key factor affecting energy consumption, accounting for 15%-20% of total energy consumption. Lower rolling resistance means that with the same battery capacity, the vehicle's driving range can be effectively extended, alleviating users' range anxiety and reducing energy consumption over the entire life cycle, aligning with sustainable development goals. This is driving a profound revolution in tire technology. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing an electric vehicle tire that incorporates high-modulus polyester carcass cords. By employing polyester cords with a specific parameter combination (elongation at constant load and dry heat shrinkage) and controlling the cord elongation at the molding drum, the load-bearing potential of the tire carcass is directly maximized, easily handling the additional load of the electric vehicle. To achieve the above objectives, this invention adopts the following technical solution: An electric vehicle tire with high-modulus polyester carcass cord, the electric vehicle tire comprising a crown, crown belt layer, belt layer, carcass, inner liner, sidewall, and bead, the carcass comprising a first carcass and a second carcass, the carcass cord strength being between 13000-22000 N / 10cm, and using polyester cord; under a calendering density of 100-110 cords / 10cm, the strength of a single polyester cord is 130-200 N; the elongation at constant load of the polyester cord is 3.5%-4.5%; the dry heat shrinkage rate of the polyester cord (177℃×2min) is 1.8%-2.2%; and the cord elongation at the forming drum is 1.020%-1.030%.

[0007] Preferably, the polyester cord has a constant load elongation of 3.5%-4.0%; a dry heat shrinkage rate (177℃×2min) of 1.8%-2.0%; and a cord elongation at the forming drum of 1.020%-1.025%.

[0008] Preferably, the thickness of the tire carcass cord fabric after coating is 0.90-1.15mm, and the thickness tolerance of the upper and lower films covering the polyester fibers is ±0.02mm.

[0009] Preferably, the bead includes a triangular rubber ring and a steel wire ring; the first tire carcass wraps around the steel wire ring and then wraps back to the upper end of the triangular rubber ring, with the back-wrapped end point located 10-20mm radially upward from the triangular rubber ring; the second tire carcass wraps around the steel wire ring, with the back-wrapped end point located 5-10mm radially upward from the steel wire ring; after the tire carcass is wrapped back, it is further fitted with a bead wrapping cloth, which has a width of 40-60mm and a thickness of 0.5-1.0mm, with its center approximately located at the end point of the triangular rubber ring, the upper end point being at least 10mm from the back-wrapped end point of the first tire carcass, and the lower end point not lower than the horizontal height of the steel wire ring.

[0010] Preferably, the radial overlap distance between the lower end of the ferrule wrapping and the second tire body reverse wrapping end is not less than 5 mm.

[0011] Preferably, the material of the ferrule covering is nylon or polyester; more preferably, the angle of the semi-finished ferrule covering cord is 45±10°.

[0012] Preferably, the Shore hardness of the triangular rubber is in the range of 85-95; more preferably, the width of the base of the lower triangular rubber (i.e., the side of the triangular rubber closer to the rim) matches the width of the upper end of the wire ring, and its lower end is designed to be wide and full.

[0013] Preferably, the tire sidewall includes a sidewall rubber, an outer protective rubber, and a shoulder pad rubber. The shoulder pad rubber is disposed below the belt layer. The sidewall rubber, the shoulder pad rubber, and the tire crown are connected. The parting surface width between the sidewall rubber and the shoulder pad rubber is not less than 15 mm, and the parting surface width between the sidewall rubber and the outer protective rubber is not less than 25 mm.

[0014] Preferably, the end of the outer protective adhesive needs to cover the inner opening fabric and extend radially upward by at least 5 mm.

[0015] Preferably, the end of the outer protective rubber is lower than the end of the first tire carcass reverse wrapping, and is at least 5 mm downward in the radial direction.

[0016] Preferably, the tire crown includes tread rubber, base rubber and shoulder rubber, and the tire crown, crown belt layer and belt layer are combined to form a two-stage tire embryo.

[0017] Preferably, the liner includes an air-retaining layer and a transition layer, and is disposed between the tire body and the tire sidewall.

[0018] This invention employs the aforementioned technical solution, utilizing polyester cords with a specific parameter combination (constant load elongation and low dry heat shrinkage) and controlling the cord elongation at the molding drum to directly maximize the load-bearing potential of the tire carcass. This allows the manufactured tire to meet the high load-bearing capacity requirements of electric vehicles while possessing low rolling resistance and good handling performance. The reinforced carcass acts like a stronger "skeleton" for the tire, providing stronger lateral support during high-speed cornering, effectively suppressing sidewall deformation, and simultaneously improving vehicle handling stability and safety limits. This invention provides clear guidance for tire design and cord production, namely, to focus on developing cord materials with low constant load elongation and low dry heat shrinkage, and to combine them with reasonable molding processes (elongation control) to fully realize their performance potential. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the cross-sectional structure of the main components of an electric vehicle tire.

[0020] Reference numerals: 1. Tire crown; 2. Crown belt layer; 3. Belt layer; 4. First carcass; 5. Second carcass; 6. Inner liner; 7. Sidewall; 8. Bead wrap; 9. Triangle rubber; 10. Bead wire. Detailed Implementation

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0022] In the description of this application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0023] A radial electric vehicle tire using polyester fiber carcass cords, the cross-sectional structure of its main components is as follows: Figure 1 As shown. The electric vehicle tire includes a crown 1, a crown belt layer 2, a belt layer 3, a tire carcass, an inner liner 6, a sidewall 7, and a bead. The crown 1 includes a tread rubber, a base rubber, and a shoulder rubber. The crown 1, crown belt layer 2, and belt layer 3 are combined to form a two-section tire carcass. The tire carcass includes a first tire carcass 4 and a second tire carcass 5. The inner liner 6 includes an air-retaining layer and a transition layer, and is disposed between the tire carcass and the sidewall 7. The sidewall 7 includes a sidewall rubber, an outer protective rubber, and a shoulder pad rubber. The shoulder pad rubber is disposed below the belt layer 3. The sidewall rubber, the shoulder pad rubber, and the crown 1 are connected. The endpoint of the outer protective rubber needs to cover the bead wrapping fabric 8 and extend radially upward by at least 5 mm, and be at least 5 mm lower than the reverse end of the first tire carcass 4 and radially downward. The bead includes a triangular rubber 9 and a steel wire bead 10. In this embodiment, the endpoint of the outer protective rubber needs to cover the bead wrapping fabric 8 and extend radially upward by 5 mm, and be at least 5 mm lower than the reverse end of the first tire carcass 4 and radially downward.

[0024] The first tire carcass 4 wraps around the steel wire ring 10 and is then reversed to the upper end of the triangular rubber ring 9, with its reversed end located 10-20 mm radially upward from the triangular rubber ring 9. The second tire carcass 5 wraps around the steel wire ring 10, with its reversed end located 5-10 mm radially upward from the steel wire ring 10. After the tire carcass is reversed, it is further fitted with the bead wrap 8, which is 40-60 mm wide and 0.5-1.0 mm thick, with its center approximately located at the end of the triangular rubber ring 9. The upper end of the bead wrap 8 is at least 10 mm from the reversed end of the first tire carcass 4, and the lower end is not lower than the horizontal height of the steel wire ring 10. Furthermore, the radial overlap between the lower end of the bead wrap 8 and the reversed end of the second tire carcass 5 is not less than 5 mm. In this embodiment, the second tire body 5 wraps around the steel wire ring 10, and its reverse end point is located 8mm radially upward from the steel wire ring 10; the width of the ferrule 8 is 50mm and the thickness is 0.8mm. The upper end point of the ferrule 8 is 10mm away from the reverse end point of the first tire body 4, and the lower end point is 3mm higher than the steel wire ring 10.

[0025] The strength of the tire cord is between 13,000 and 22,000 N / 10cm; under a calendering density of 100-110 cords / 10cm, the strength of a single cord is 130-200 N; the elongation at constant load of the polyester cord is 3.5%-4.5%; the dry heat shrinkage rate of the polyester cord (177℃×2min) is 1.8%-2.2%; and the cord elongation at the forming drum is 1.020%-0.030%. More preferably, the elongation at constant load of the polyester cord is 3.5%-4.0%; the dry heat shrinkage rate of the polyester cord (177℃×2min) is 1.8%-2.0%; and the cord elongation at the forming drum is 1.020%-0.025%.

[0026] Furthermore, the thickness of the tire carcass ply after adhesive coating is 0.90-1.15 mm, and the thickness tolerance of the upper and lower films covering the polyester fibers is ±0.02 mm. In this embodiment, the thickness of the tire carcass ply after adhesive coating is 1.0 mm.

[0027] Furthermore, the material of the lining 8 is nylon or polyester. In this embodiment, the material of the lining 8 is nylon.

[0028] Furthermore, the semi-finished cord angle of the ferrule-covered fabric 8 is 45±10°. In this embodiment, the semi-finished cord angle of the ferrule-covered fabric 8 is 45°.

[0029] Furthermore, the Shore hardness range of the triangular adhesive 9 is 85-95. In this embodiment, the Shore hardness of the triangular adhesive 9 is 85.

[0030] Furthermore, the width of the lower triangular rubber base 9 matches the width of the upper end of the steel wire ring 10, and its lower end is designed to be wide and full.

[0031] Furthermore, the parting surface width between the sidewall rubber and the shoulder pad rubber is not less than 15mm, and the parting surface width between the sidewall rubber 7 and the outer protective rubber is not less than 25mm. In this embodiment, the parting surface width between the sidewall rubber and the shoulder pad rubber is 15mm, and the parting surface width between the sidewall rubber 7 and the outer protective rubber is 25mm.

[0032] This embodiment uses a tire with a specification of 235 / 45ZR18 for development testing. The tire carcass uses 1100 dtex / 2 polyester cord with a calendering thickness of 1.05 mm and a calendering density of 110 cords / 10 cm. While maintaining consistent basic physical properties of the cord, the effects of different combinations of three variables—elongation at constant load, dry heat shrinkage, and cord elongation at the forming drum—on tire performance were systematically studied. The cord performance parameters and forming elongation are shown in Table 1, and the tire performance test results are shown in Table 2.

[0033] The performance testing of finished tires was conducted in accordance with GB / T 4502—2016 "Indoor Test Methods for Passenger Car Tire Performance", GB / T29040—2012 "Test Methods for Rolling Resistance of Automobile Tires: Single-Point Tests and Correlation of Measurement Results", ECE R30 "Uniform Regulations for the Approval and Certification of Certain Pneumatic Tires for Motor Vehicles", and US FMVSS 139, among other standards. Tire performance test results were normalized and compared based on a percentage; a higher percentage indicates better performance.

[0034] Table 1 Cord performance parameters and forming elongation

[0035] Table 2 Comparison of Tire Performance Test Results

[0036] Table 2 shows that by optimizing cord performance parameters and molding process (controlling cord elongation at the molding drum), a comprehensive improvement in high-speed performance, handling stability (lateral / radial stiffness), and fuel economy (rolling resistance) can be achieved while ensuring basic tire safety performance. Among all embodiments, Embodiments 6 and 7 performed best. Embodiment 6 showed greater advantage in rolling resistance optimization, while Embodiment 7 performed best in lateral stiffness. It is evident that using cords with low constant load elongation (3.5%) and low dry heat shrinkage (1.8%) can significantly improve the overall performance of the tire.

[0037] To further evaluate the tire's handling performance in actual driving, a real-vehicle handling performance test was conducted using the reference scale and Example 6, and the results are shown in Table 3.

[0038] Table 3 Subjective Evaluation of Vehicle Handling Performance

[0039] As shown in Table 3, Example 6 exhibits superior handling stability during turning, acceleration, and braking, with a more sensitive response in the central area, and improved vibration control and overall smoothness at high speeds.

[0040] Based on the above test results, Example 6 is the optimal implementation scheme. By using cords with low constant load elongation (3.5%) and low dry heat shrinkage (1.8%), and controlling the cord elongation at the forming drum to 1.025%, the handling performance of electric vehicle tires can be effectively improved and rolling resistance reduced.

[0041] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. An electric vehicle tire with high-modulus polyester carcass cord, characterized in that, The electric vehicle tire includes a crown, crown belt layer, belt layer, tire carcass, inner liner, sidewall, and bead. The tire carcass includes a first tire carcass and a second tire carcass. The ply strength of the tire carcass is between 13,000 and 22,000 N / 10 cm, and it uses polyester cord. Under the condition of a calendering density of 100-110 cords / 10 cm, the strength of a single polyester cord is 130-200 N; the elongation at constant load of the polyester cord is 3.5%-4.5%; the dry heat shrinkage rate of the polyester cord (177℃×2 min) is 1.8%-2.2%; and the cord elongation at the forming drum is 1.020%-1.030%.

2. The electric vehicle tire with high-modulus polyester carcass cord according to claim 1, characterized in that, The polyester cord has a constant load elongation of 3.5%-4.0%; a dry heat shrinkage rate (177℃×2min) of 1.8%-2.0%; and a cord elongation at the forming drum of 1.020%-1.025%.

3. The electric vehicle tire with high-modulus polyester carcass cord according to claim 1, characterized in that, The thickness of the tire cord fabric after coating is 0.90-1.15mm, and the thickness tolerance of the upper and lower films covering the polyester fibers is ±0.02mm.

4. An electric vehicle tire with a high-modulus polyester carcass cord according to claim 1 or 2, characterized in that, The tire bead includes a triangular rubber ring and a steel wire ring; the first tire carcass wraps around the steel wire ring and then wraps back to the upper end of the triangular rubber ring, with the reversed end point located 10-20mm radially upward from the triangular rubber ring; the second tire carcass wraps around the steel wire ring, with the reversed end point located 5-10mm radially upward from the steel wire ring; after the tire carcass is reversed, it is further fitted with a bead wrapping cloth, which has a width of 40-60mm, a thickness of 0.5-1.0mm, an upper end point at least 10mm from the reversed end point of the first tire carcass, and a lower end point not lower than the horizontal height of the steel wire ring.

5. An electric vehicle tire with a high-modulus polyester carcass cord according to claim 3, characterized in that, The radial overlap distance between the lower end of the sub-mouth wrapping fabric and the second tire body reverse wrapping end shall not be less than 5mm; And / or, the material of the ferrule covering is nylon or polyester; more preferably, the semi-finished cord angle of the ferrule covering is 45±10°.

6. An electric vehicle tire with a high-modulus polyester carcass cord according to claim 3, characterized in that, The Shore hardness range of the triangular rubber is 85-95; preferably, the width of the lower triangular rubber base matches the width of the upper end of the wire ring.

7. An electric vehicle tire with a high-modulus polyester carcass cord according to claim 3, characterized in that, The tire sidewall includes a sidewall rubber, an outer protective rubber, and a shoulder pad rubber. The shoulder pad rubber is located below the belt layer. The sidewall rubber, the shoulder pad rubber, and the tire crown are connected. The parting surface width between the sidewall rubber and the shoulder pad rubber is not less than 15 mm, and the parting surface width between the sidewall rubber and the outer protective rubber is not less than 25 mm.

8. An electric vehicle tire with a high-modulus polyester carcass cord according to claim 7, characterized in that, The end of the outer protective adhesive must be covered with the inner opening fabric and extend upward in the radial direction by at least 5 mm; And / or, the endpoint of the outer protective rubber is lower than the endpoint of the first carcass reverse wrapping, at least 5 mm downward in the radial direction.

9. An electric vehicle tire with a high-modulus polyester carcass cord according to claim 1 or 2, characterized in that, The tire crown includes tread rubber, base rubber and shoulder rubber, and the tire crown, crown belt layer and belt layer are combined to form a two-section tire embryo; And / or, the liner includes an air-retaining layer and a transition layer, and is disposed between the tire body and the tire sidewall.

Images