A pre-grooved tread compound for preventing non-symmetrical tread arching

Abstract

The application relates to the technical field of tire manufacturing, and discloses a pre-groove tread type rubber for preventing non-symmetrical tread arch. A preset groove corresponding to the position of a finished product main groove is arranged on the outer surface of a crown rubber layer, the ratio relationship between the size of the preset groove and the parameters of the main groove is limited, the residual crown rubber thickness of the preset groove is controlled, a base rubber thickness correction coefficient is introduced, the corresponding relationship between the cross-sectional area moment of the preset groove and the corrected area moment of the base rubber thickness of the main groove is established, and the two satisfy a specific proportion range, so that the uneven distribution of rubber caused by the non-symmetrical main groove is compensated. The structure can effectively inhibit the tread arch, improve the uniformity of tread forming and the stability of the tire structure.

Description

Technical Field

[0001] This invention relates to the field of tire manufacturing technology, and more specifically, to a pre-grooved tread profile rubber for preventing asymmetric tread pattern arches. Background Technology

[0002] Tire treads typically consist of a crown rubber layer and a base rubber layer beneath it. The crown rubber layer primarily provides wear resistance, grip, and cut resistance, while the base rubber layer mainly reduces heat generation, improves cushioning, and adjusts the overall tread stiffness. In asymmetric tread pattern tires, the number, width, depth, and lateral position of the main grooves are often not perfectly symmetrical relative to the tread center. During the vulcanization process, the main groove forming ribs are pressed into the crown rubber layer, causing the rubber material at the corresponding locations to flow to both sides. When the cross-sectional area and position of the main grooves in an asymmetric tread pattern are unevenly distributed, the volume of rubber discharged and the lateral discharge force generated by the pressing of the main groove forming ribs will also be uneven. This can easily cause the tread rubber to bulge in local areas of the crown, or cause the base rubber to arch upwards towards the bottom of the main grooves, thus affecting the rubber thickness at the bottom of the main grooves, the distribution of tread contact pressure, and the tire's appearance quality.

[0003] Chinese invention patent CN110815888B discloses a tire processing and molding method. Before mold forming and vulcanization, a rubber blank is pre-pressed into a billet using a die-casting machine. This billet has pre-formed grooves and pre-formed protrusions corresponding to the tire forming mold. The method discloses that the rubber thickness *d* at the bottom reference point of the groove and the rubber thickness *D* at the bottom of the main groove after mold forming satisfy dimensional relationships such as *D / d* = 0.7~0.9 and *L / l* = 0.2~0.25. This technology can guide the orderly distribution of rubber and reduce rubber accumulation at the edges of the tread pattern. However, this technology mainly focuses on the correspondence between the pre-formed grooves and protrusions and the mold structure, emphasizing the overall pre-forming of the billet and the uniform distribution of rubber in the tread pattern. It does not establish a compensation relationship for the tread arch problem caused by the combined effects of the main groove cross-sectional area, the lateral position of the main groove, and the base rubber thickness in asymmetrical tread patterns.

[0004] Chinese invention patent CN110936579A discloses a tread extrusion die assembly for a wide-base tire with a small shoulder pad. This assembly addresses issues such as grooves and wavy lines at the bottom of the tread by setting sharp corners and arc-shaped opening surfaces on the die plate, and adjusting the fit between the die plate and the pre-die plate. The key to this solution lies in the structural improvement of the extrusion die assembly, which influences the pressure and flow state of the tread rubber during extrusion through the local shape of the die plate. While this technology involves tread rubber flow and groove bottom formation, it primarily addresses the flatness and groove issues at the bottom of the extruded tread. It does not disclose setting a pre-set groove at a predetermined position on the finished main groove on the outer surface of the tread rubber layer, nor does it disclose determining the cross-sectional area moment of the pre-set groove after correcting the area moment of the main groove based on the thickness of the base rubber layer. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a pre-grooved tread profile rubber for preventing asymmetric tread camber. By adjusting the area moment distribution of the base rubber thickness to allocate the pre-release amount of rubber material in the preset groove, the probability of tread camber and base rubber camber generated during the vulcanization of asymmetric tread patterns is reduced.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A pre-grooved tread profile rubber for preventing asymmetric tread patterns includes a crown rubber layer and a base rubber layer disposed below the crown rubber layer. The crown rubber layer has an outer surface corresponding to the main groove forming rib of the vulcanizing mold. Multiple preset grooves are provided on the outer surface along the length direction of the tread profile rubber, and the multiple preset grooves are respectively located at the set positions of the main groove of the finished tread.

[0008] Definition of the first The opening width of each preset groove is Depth is The cross-sectional area is The corresponding first The opening width of the main groove of each finished tire tread is The depth of the main groove of the finished tire tread is The cross-sectional area of ​​the main groove of the finished tire tread is ,in:

[0009]

[0010] Definition of the first The location of each preset groove, when no preset groove is set, is determined by the thickness of the tread rubber layer from its outer surface to the interface between the tread rubber layer and the base rubber layer. The thickness of the base adhesive layer is The remaining tread rubber thickness from the bottom of the preset groove to the interface between the tread rubber layer and the base rubber layer is... ,in:

[0011]

[0012] And the remaining crown rubber thickness satisfy:

[0013] max(0.8mm, 0.18) )≤ ≤min(2.2mm,0.55 )

[0014] Define the centerline of the conductive rubber in the tread compound as the reference centerline; when no conductive rubber strip is provided, use the geometric centerline of the tread compound as the reference centerline; The lateral distance from the center of the main groove of each finished tire tread to the reference center line is: With one side of the reference centerline as positive and the other side as negative, the average thickness of the base rubber layer at multiple finished tire tread main groove locations is... ,in:

[0015]

[0016] No. Correction factor for base rubber thickness at the main groove position of each finished tire tread satisfy:

[0017]

[0018] Cross-sectional area of ​​multiple pre-set grooves and the base rubber thickness correction area of ​​multiple finished tire tread main grooves They respectively satisfy:

[0019]

[0020]

[0021] in, , and Same sign, and satisfying:

[0022]

[0023] Using the reference center line as the boundary, the multiple finished tire tread main grooves are divided into a first side main groove and a second side main groove; when the absolute value of the base rubber thickness correction area moment corresponding to the first side main groove is greater than the absolute value of the base rubber thickness correction area moment corresponding to the second side main groove, the average cross-sectional area of ​​the first side preset groove is greater than the average cross-sectional area of ​​the second side preset groove, and the average remaining tread rubber thickness of the first side preset groove is not less than 0.85 times the average remaining tread rubber thickness of the second side preset groove.

[0024] Preferably, the preset groove is a trapezoidal groove, a circular arc bottom groove, or a composite groove formed by a combination of trapezoidal sidewalls and a circular arc bottom.

[0025] Preferably, when the preset groove is a trapezoidal groove, the bottom width of the preset groove is 0.18 to 0.55 times its opening width, and the angle between the sidewall of the groove and the thickness direction of the tread rubber is 15° to 45°.

[0026] Preferably, the lateral offset between the centerline of the preset groove and the centerline of the corresponding main groove of the finished tire tread is no greater than 0.08. And not greater than 0.6mm.

[0027] Preferably, the average cross-sectional area of ​​the preset groove on the side with a larger contribution of the base adhesive thickness correction area moment is 1.2 to 2.0 times that of the average cross-sectional area of ​​the preset groove on the side with a smaller contribution of the base adhesive thickness correction area moment.

[0028] Preferably, the edge of the groove of the preset groove is transitioned to the outer surface of the tire crown rubber layer by a rounded corner, and the radius of the rounded corner is 0.3mm to 1.2mm.

[0029] Preferably, the preset groove is formed by extrusion through a tread extrusion die in one step, or by pressing it in with a pressure roller after the tread adhesive is extruded, or by cutting it after the tread adhesive is extruded.

[0030] A method for preparing a pre-grooved tread profile compound for preventing asymmetric tread patterns, the method comprising the following steps:

[0031] S1. Determine the opening width, depth, cross-sectional area, and lateral position of multiple finished tread main grooves based on the asymmetric tread pattern;

[0032] S2. Determine the thickness of the base rubber layer at the designated positions of the main grooves of multiple finished tire treads, and calculate the average thickness of the base rubber layer. Base adhesive thickness correction factor and base adhesive thickness correction area moment ;

[0033] S3. Adjust the area moment according to the thickness of the base adhesive. Determine the cross-sectional area, opening width, and depth of multiple preset grooves, such that the cross-sectional area of ​​the multiple preset grooves is perpendicular to the opening width and depth. Area moment with respect to the thickness of the base adhesive Same sign, and satisfy ;

[0034] S4. Check the remaining tread rubber thickness of each preset groove based on the tread rubber layer thickness and the base rubber layer thickness. ;

[0035] S5. Multiple preset grooves extending along the length of the tread rubber layer are formed on the outer surface of the tread rubber layer, and the multiple preset grooves are respectively located at the set positions of the main groove of the finished tread.

[0036] This invention establishes multiple pre-set grooves on the outer surface of the tread rubber layer at predetermined positions corresponding to the main grooves of the finished tread. The opening width, depth, and cross-sectional area of ​​these pre-set grooves are defined as specific proportions to the dimensions of the main grooves in the finished tread. This creates a controlled pre-release zone of rubber material at the main groove position before the forming ribs of the vulcanizing mold are pressed in. Simultaneously, based on the cross-sectional area of ​​each main groove, the lateral distance from the center of the main groove to the reference center line, and the thickness of the base rubber layer at that main groove position, this invention establishes a base rubber thickness correction area moment. The cross-sectional area moments of the multiple pre-set grooves are kept in the same sign as this correction area moment and within a specific ratio range, thus matching the rubber removal distribution of the pre-set grooves with the uneven rubber discharge caused by asymmetrical tread patterns. Furthermore, this invention, through the constraint relationship between the remaining tread rubber thickness and the base rubber layer thickness, avoids insufficient tread rubber at the bottom of the main groove or arching of the base rubber due to excessively deep pre-set grooves. Therefore, this invention can significantly reduce asymmetrical tread arching, reduce rubber thickness deviation at the bottom of the main groove, reduce rubber overflow at the edge of the main groove, and improve the consistency of the tread cross-section and tire forming quality after vulcanization. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the cross-sectional structure of the pre-grooved tread rubber for preventing asymmetric tread patterns according to the present invention.

[0038] Reference numerals: 11-Crown rubber layer; 12-Base rubber layer; 13-Preset groove; 14-Set position of the main groove of the finished tread; 15-Conductive rubber strip; 16-Reference center line; 17-Interface between crown rubber layer and base rubber layer. Detailed Implementation

[0039] 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.

[0040] 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.

[0041] like Figure 1As shown, the present invention provides a pre-grooved tread profile for preventing asymmetric tread patterns. The tread profile includes a crown rubber layer 11 and a base rubber layer 12 disposed below the crown rubber layer 11. The crown rubber layer 11 forms a wear-resistant rubber layer that contacts the ground, while the base rubber layer 12, located below the crown rubber layer 11, improves the heat generation, cushioning, and overall support performance of the tread profile. The crown rubber layer 11 has an outer surface facing the main groove forming rib of the vulcanizing mold. Multiple pre-set grooves 13 are provided on this outer surface along the length of the tread profile, and these grooves 13 are respectively located at predetermined positions 14 of the main groove of the finished tread.

[0042] The pre-set groove 13 described in this invention is not the final main groove of the finished tire, but a shallow groove pre-formed on the outer surface of the crown rubber layer 11 before the tread rubber is vulcanized. During vulcanization, the main groove forming rib of the vulcanization mold is pressed into the tread rubber. The area where the pre-set groove 13 is located has already reduced a portion of the rubber material that needs to be extruded, thus reducing the degree of uneven flow of rubber material to both sides when the main groove forming rib is pressed in. For Figure 1 The asymmetrical tread pattern shown has a non-symmetrical distribution of the main grooves relative to the reference center line 16. If a flat tread rubber is still used, the forming ribs on different sides of the main grooves will generate different rubber discharge volumes and lateral rubber discharge forces during vulcanization, which can easily lead to tread arching, base rubber arching, or uneven rubber thickness at the bottom of the main grooves. This invention controls the pre-release amount of rubber in the preset grooves 13 by adjusting the size of the preset grooves 13 and the area moment of the base rubber thickness correction, so that the pre-release amount of rubber in the preset grooves 13 matches the asymmetrical main groove distribution.

[0043] Definition of the first The opening width of each preset groove 13 is Depth is The cross-sectional area is The first corresponding to the preset groove 13 The opening width of the main groove of each finished tire tread is The depth of the main groove of the finished tire tread is The cross-sectional area of ​​the main groove of the finished tire tread is The opening width, depth, and cross-sectional area of ​​the preset groove 13 satisfy the following relationship:

[0044]

[0045]

[0046] .

[0047] The above relationship indicates that the pre-set groove 13 is not a simple replication of the finished tire tread main groove, but rather a partial pre-release based on the finished tire tread main groove. If Less than or Less than If the volume of rubber material released by the preset groove 13 is insufficient, significant local rubber discharge will still occur during vulcanization of the main groove forming rib; if Greater than or Greater than If the pre-set groove 13 is too wide or too deep, it can easily weaken the thickness of the tread rubber at the bottom of the main groove, and even exacerbate the upward arching of the base rubber layer 12. Controlled to This allows the pre-release volume of the preset groove 13 to be kept within a range that can reduce the tread arch without excessively weakening the crown rubber layer 11.

[0048] Definition of the first The location of each preset groove 13, when no preset groove is set, is such that the thickness of the tread rubber layer from the outer surface of the tread rubber layer to the interface between the tread rubber layer and the base rubber layer is [missing information]. The thickness of the base adhesive layer is The remaining crown rubber thickness from the bottom 18 of the preset groove 13 to the interface 17 between the crown rubber layer 11 and the base rubber layer 12 is... .in:

[0049]

[0050] In the formula, For the first The thickness of the tire crown rubber retained below the bottom of the pre-set groove 13 and groove 18. The thickness of the front tire crown rubber layer 11 along the thickness direction is the area where the pre-defined groove 13 is not formed. The depth of the preset groove 13 along the tread rubber thickness direction.

[0051] The remaining crown rubber thickness satisfy:

[0052] max(0.8mm, 0.18) )≤ ≤min(2.2mm,0.55 )

[0053] The purpose of this relationship is to keep the bottom 18 of the preset groove 13 and the base adhesive layer 12 within a controlled distance. If If the thickness is too small, the tread rubber layer 11 at the bottom of the main groove will be too thin, and the base rubber layer 12 will easily be squeezed upwards into the bottom area of ​​the main groove during vulcanization, resulting in unstable rubber thickness at the bottom of the main groove; if... If the groove is too large, it indicates that the preset groove 13 is too shallow, failing to fully release the volume of rubber material when the main groove forming rib is pressed in, resulting in insufficient improvement in the tread arch. Therefore, Simultaneously affected by both absolute thickness and base adhesive layer thickness The constraints can balance the arch reduction effect of the pre-excavated trench with the safety of the adhesive thickness at the bottom of the main trench.

[0054] In a tread compound with conductive rubber strips 15, the conductive rubber strips 15 are typically arranged along the length of the tread compound and located at a specific position on the crown rubber layer 11 in cross-section. Since the position of the conductive rubber strips 15 often corresponds to the tread center that needs to be controlled during actual molding and vulcanization, this embodiment preferably uses the centerline of the conductive rubber strips 15 as the reference centerline 16. When conductive rubber strips 15 are not provided, the geometric centerline of the tread compound is used as the reference centerline 16.

[0055] Definition of the first The lateral distance from the center of the main groove of the finished tire tread to the reference centerline 16 is With one side of the reference centerline 16 as positive and the other side as negative, the average thickness of the base rubber layer at multiple finished tire tread main groove locations is... ,in:

[0056]

[0057] In the formula, This refers to the number of main grooves in the finished tire tread. For the first The thickness of the base rubber layer at the main groove position of the finished tire tread.

[0058] No. Correction factor for base rubber thickness at the main groove position of each finished tire tread satisfy:

[0059]

[0060] In the formula, This is used to reflect the impact of differences in the thickness of the base adhesive layer 12 at different locations in the main trench on the arching and lateral discharge of the adhesive compound. When the thickness of the base adhesive layer 12 at a certain location in the main trench is greater than the average thickness... A value greater than 1 indicates that the influence of the base rubber layer 12 on vulcanization rubber discharge and tread arch should be amplified; when the thickness of the base rubber layer 12 at a certain main groove location is less than the average thickness, A value less than 1 indicates that the impact at that point is relatively small.

[0061] Cross-sectional area of ​​multiple preset grooves 13 and the base rubber thickness correction area of ​​multiple finished tire tread main grooves They respectively satisfy:

[0062] .

[0063] and The same sign indicates that the pre-release direction of the adhesive in the preset groove 13 is consistent with the direction of uneven adhesive discharge caused by the asymmetric main groove and the thickness of the base adhesive. A ratio between 0.35 and 0.55 indicates that the pre-set groove 13 does not completely offset the adhesive discharge effect of the finished main trench, but rather releases a portion of the adhesive volume in advance. If this ratio is less than 0.35, the compensation is insufficient; if it is greater than 0.55, it can easily lead to excessive weakening of the pre-dug trench side, resulting in insufficient adhesive thickness at the bottom of the main trench or adhesive arching at the base.

[0064] Using the reference centerline 16 as a boundary, multiple finished tread main grooves are divided into a first side main groove and a second side main groove. The contribution of the base rubber thickness correction area moment on each side is calculated separately. When the absolute value of the base rubber thickness correction area moment corresponding to the first side main groove is greater than the absolute value of the base rubber thickness correction area moment corresponding to the second side main groove, the average cross-sectional area of ​​the preset groove on the first side is greater than the average cross-sectional area of ​​the preset groove on the second side. Preferably, the average cross-sectional area of ​​the preset groove on the larger side is 1.2 to 2.0 times that of the smaller side, more preferably 1.5 to 1.9 times; and the average remaining crown rubber thickness of the preset groove on the first side is not less than 0.85 times the average remaining crown rubber thickness of the preset groove on the second side. The average cross-sectional area is obtained by dividing the sum of the cross-sectional areas of all preset grooves on the corresponding side by the number of preset grooves on that side. This structure allows the side with a larger tread arch to obtain a larger pre-release rubber area, while avoiding excessive digging on that side, which would make the crown rubber layer 11 locally too thin.

[0065] In one embodiment, the pre-set groove 13 is a trapezoidal groove. The bottom width of the trapezoidal groove is 0.18 to 0.55 times its opening width, and the angle between the groove sidewall and the tread rubber thickness direction is 15° to 45°. The trapezoidal groove can form a relatively stable groove edge 19 during pre-grooving, and the rubber material gradually flows along the groove sidewall during vulcanization, avoiding local shear concentration. In another embodiment, the pre-set groove 13 is a rounded bottom groove. The bottom 18 of the rounded bottom groove has no sharp corners, which can reduce the possibility of local stress concentration in the tread rubber layer 11 at the bottom 18. In yet another embodiment, the pre-set groove 13 is a composite groove formed by a combination of trapezoidal sidewalls and a rounded bottom, which has the advantages of stable groove opening positioning and stress relief at the bottom.

[0066] The lateral offset between the centerline of the preset groove 13 and the centerline of the corresponding finished tire tread main groove is no greater than The groove 13 should be no larger than 0.6 mm. This limitation ensures that the pre-groove 13 is aligned with the main groove forming rib of the vulcanizing mold, preventing the pre-groove 13 from deviating from the pressing area of ​​the main groove forming rib and reducing the pre-release effect. The groove edge 19 of the pre-groove 13 is preferably transitioned to the outer surface of the tread rubber layer 11 by a rounded corner with a radius of 0.3 mm to 1.2 mm, to prevent the groove edge 19 from tearing or local wrinkling during the handling, bonding and vulcanization of the tread rubber.

[0067] The preparation method of pre-grooved tread compound includes the following steps:

[0068] S1. Determine the opening width, depth, cross-sectional area, and lateral position of multiple finished tread main grooves based on the asymmetric tread pattern. Specifically, the dimensions of each finished tread main groove can be obtained from the tread pattern design drawing or vulcanizing mold cavity data. , , and .in, It can be obtained from the cross-sectional profile of the main groove using computer-aided design software, or it can be calculated by measuring and converting the cross-sectional profile of the forming rib of the main groove of the mold.

[0069] S2. Determine the thickness of the base rubber layer at the designated positions of the main grooves of multiple finished tire treads, and calculate the average thickness of the base rubber layer. Base adhesive thickness correction factor and base adhesive thickness correction area moment Specifically, the thickness of the base rubber layer 12 at each main groove setting position 14 is measured on the cross-section after the tread rubber is extruded. ,calculate and Then according to the formula The area moment of the base adhesive thickness correction is obtained.

[0070] S3. Adjust the area moment according to the thickness of the base adhesive. Determine the cross-sectional area, opening width, and depth of multiple preset grooves 13, such that the cross-sectional area of ​​the multiple preset grooves 13 is perpendicular to the cross-sectional area of ​​the grooves 13. Area moment with base adhesive thickness correction Same number, and make In determining Then, further combine the corresponding finished tire tread main grooves , and ,Sure and .

[0071] S4. Based on the thickness of the tread rubber layer and base adhesive layer thickness Check the remaining tread rubber thickness of each preset groove 13. If a certain preset groove 13 Less than If so, reduce the depth of the preset groove 13, or appropriately increase its opening width while maintaining the cross-sectional area; if Greater than If necessary, the depth of the preset groove 13 can be increased, or the width of the groove bottom can be reduced to improve the pre-release effect.

[0072] S5. Multiple pre-set grooves 13 extending along the length of the tread rubber layer 11 are formed on the outer surface of the tread rubber layer 11, and the multiple pre-set grooves 13 are respectively located at the set positions 14 of the main groove of the finished tread. The pre-set grooves 13 can be formed by one-time extrusion through a tread extrusion die, or by pressing in with a pressure roller after the tread rubber is extruded, or by cutting after the tread rubber is extruded. When forming in one step using an extrusion die, the dimensional stability of the pre-set grooves 13 is better; when pressing in with a pressure roller, it is easy to modify the existing extrusion production line; when using the cutting method, it is easy to conduct small-batch trial production and test verification.

[0073] Example 1

[0074] Table 1

[0075]

[0076] According to calculations, in this embodiment:

[0077]

[0078] This value is within the range of 0.35 to 0.55. The contribution of the base rubber thickness correction area moment of the first main groove (first and second main grooves) is greater than that of the second main groove (third and fourth main grooves). The average cross-sectional area of ​​the preset groove on the first side is 1.86 times that of the average cross-sectional area of ​​the preset groove on the second side, which is within the range of 1.2 to 2.0. When the average cross-sectional area of ​​the preset groove on one side is less than 1.20 times that of the other side, the compensation for uneven rubber distribution caused by the asymmetrical main groove is insufficient; when the ratio is greater than 2.00 times, it is easy to cause excessive excavation of the preset groove on that side, resulting in localized thinning of the tread rubber or causing the base rubber to arch upwards. The average remaining tread rubber thickness of the preset groove on the first side is 1.11 times that of the average remaining tread rubber thickness of the preset groove on the second side, which meets the requirement of not less than 0.85 times.

[0079] Comparative Example 1

[0080] Without the preset groove 13, the outer surface of the tread rubber layer 11 maintains the conventional tread rubber outline. This design is used to verify the improvement effect of the preset groove 13 on asymmetrical tread arches.

[0081] Comparative Example 2

[0082] Preset grooves 13 are provided, but all preset grooves 13 have a uniform depth and the area is not adjusted according to the thickness of the base adhesive. Distribute the cross-sectional area. The pre-set grooves 13 in this group... Approximately 0.25, calculated as follows The value is lower than the lower limit of 0.35 defined in this invention. This scheme is used to verify the effect when the compensation is insufficient.

[0083] Comparative Example 3

[0084] A preset groove 13 is provided, but to achieve a greater arch reduction effect, the preset groove 13 on the side that contributes more is excessively deepened. In this group The value is higher than the upper limit of 0.55 defined in this invention, and in some locations... <0.18 This scheme is used to verify the risks of overcompensation and insufficient remaining tread rubber thickness.

[0085] Comparative Example 4

[0086] In this group While within the scope of this invention, the edge of the preset groove 13 lacks a rounded transition, resulting in sharp angles in some sections. This design is used to verify the impact of the rounded corners on the stability of the preset groove edge.

[0087] The testing method is as follows:

[0088] 1) Tread arch height difference: A three-dimensional laser profilometer was used for detection. Twelve sections were selected at equal intervals along the circumference of each tire. The height of the left and right shoulders and the height of the central area on the outer surface of the tread crown were read on each section. The maximum height difference caused by the non-design arch was calculated, and the average value of the 12 sections of each tire was taken.

[0089] 2) Deviation of tread rubber thickness at the bottom of the main groove: The slicing measurement method is used for detection. Three tires are randomly selected from each group, and four circumferential slices are selected from each tire. The thickness of the tread rubber at the bottom of the main groove of each finished product is measured, and the maximum deviation relative to the design value is calculated.

[0090] 3) Base rubber arching amount: The slice image analysis method is used to detect the maximum distance of the base rubber layer arching towards the bottom area of ​​the main groove, based on the design curve of the interface between the tread rubber layer and the base rubber layer.

[0091] 4) Main groove overflow: This is obtained through visual inspection of the main groove area after vulcanization. All main grooves of each tire are selected, and the lengths of obvious overflow and local rubber accumulation at the edge of the main groove are counted and converted into the overflow length per meter of main groove length.

[0092] The test subjects were the tread compound of asymmetrical patterned all-steel radial truck tires of the same specification. The cross-section of the tread compound was similar to that of... Figure 1 The structures shown are consistent. The tread rubber layer uses the same batch of tread rubber formulation, and the base rubber layer uses the same batch of base rubber formulation. All samples were prepared using the same extrusion line and were left to stand in an environment of 23±2℃ and 50%±10% relative humidity for 4 hours before molding and vulcanization. Ten tread rubber profiles were prepared for each group, and ten tires were molded and vulcanized.

[0093] Table 2 Test Results

[0094]

[0095] As can be seen from the results in the table, in Comparative Example 1, no preset groove 13 was set. During vulcanization, after the main groove forming rib was pressed into the tread rubber, the rubber material migrated unevenly to the side of the asymmetric main groove with a smaller contribution and to the local area of ​​the tread crown, resulting in a tread arch height difference of 1.34 mm and an overflow length of 38.5 mm per meter at the edge of the main groove.

[0096] Although Comparative Example 2 has a preset groove 13, If the volume of pre-released rubber is below 0.35, the tread arch height difference is still 0.92mm, indicating that simply setting the ordinary preset groove 13 cannot fully solve the problem of asymmetrical tread arch.

[0097] Comparative Example 3 Above 0.55, although the tread arch height difference decreases to 0.61mm, the maximum deviation of the tread rubber thickness at the bottom of the main groove increases to 15.2%, and the maximum upward arch of the base rubber reaches 0.58mm. This indicates that excessive pre-cutting weakens the tread rubber layer 11 at the bottom of the main groove, resulting in the upward arch of the base rubber layer 12 and unstable rubber thickness.

[0098] Comparative Example 4 Within the specified range, but without rounded corners at the groove, local deformation of the groove edge during vulcanization and bonding resulted in a deviation in the length of overflow rubber at the edge of the main groove and the thickness of the tire crown rubber at the bottom of the main groove that was still higher than in Example 1.

[0099] 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. A pre-grooved tread pattern rubber for preventing asymmetric tread arches, characterized in that, It includes a crown rubber layer and a base rubber layer disposed below the crown rubber layer. The crown rubber layer has an outer surface corresponding to the main groove forming rib of the vulcanizing mold. A plurality of preset grooves are provided on the outer surface extending along the length direction of the tread rubber. The plurality of preset grooves are respectively located at the set position of the main groove of the finished tread. Definition of the first The opening width of each preset groove is Depth is The cross-sectional area is The corresponding first The opening width of the main groove of each finished tire tread is The depth of the main groove of the finished tire tread is The cross-sectional area of ​​the main groove of the finished tire tread is ,in: ； ； ； Definition of the first The location of each preset groove, when no preset groove is set, is determined by the thickness of the tread rubber layer from its outer surface to the interface between the tread rubber layer and the base rubber layer. The thickness of the base adhesive layer is The remaining tread rubber thickness from the bottom of the preset groove to the interface between the tread rubber layer and the base rubber layer is... ,in: ； And the remaining crown rubber thickness satisfy: ； Define the centerline of the conductive rubber in the tread compound as the reference centerline; when no conductive rubber strip is provided, use the geometric centerline of the tread compound as the reference centerline; The lateral distance from the center of the main groove of each finished tire tread to the reference center line is: With one side of the reference centerline as positive and the other side as negative, the average thickness of the base rubber layer at multiple finished tire tread main groove locations is... ,in: ； No. Correction factor for base rubber thickness at the main groove position of each finished tire tread satisfy: ； Cross-sectional area of ​​multiple pre-set grooves and the base rubber thickness correction area of ​​multiple finished tire tread main grooves They respectively satisfy: ； ； in, , and Same sign, and satisfying: ； Using the reference center line as the boundary, the multiple finished tire tread main grooves are divided into a first side main groove and a second side main groove; when the absolute value of the base rubber thickness correction area moment corresponding to the first side main groove is greater than the absolute value of the base rubber thickness correction area moment corresponding to the second side main groove, the average cross-sectional area of ​​the first side preset groove is greater than the average cross-sectional area of ​​the second side preset groove, and the average remaining tread rubber thickness of the first side preset groove is not less than 0.85 times the average remaining tread rubber thickness of the second side preset groove.

2. The pre-grooved tread profile rubber for preventing asymmetric tread pattern arches according to claim 1, characterized in that, The preset groove is a trapezoidal groove, a circular arc bottom groove, or a composite groove formed by a combination of trapezoidal sidewalls and a circular arc bottom.

3. The pre-grooved tread profile rubber for preventing asymmetric tread pattern arches according to claim 2, characterized in that, When the preset groove is a trapezoidal groove, the bottom width of the preset groove is 0.18 to 0.55 times its opening width, and the angle between the sidewall of the groove and the thickness direction of the tread rubber is 15° to 45°.

4. The pre-grooved tread profile rubber for preventing asymmetric tread pattern arches according to claim 1, characterized in that, The lateral offset between the centerline of the preset groove and the centerline of the corresponding finished tire tread main groove is no greater than 0.

08. And not greater than 0.6mm.

5. The pre-grooved tread profile rubber for preventing asymmetric tread pattern arches according to claim 1, characterized in that, The average cross-sectional area of ​​the preset groove on the side with a larger contribution of the base adhesive thickness correction area moment is 1.2 to 2.0 times that of the average cross-sectional area of ​​the preset groove on the side with a smaller contribution of the base adhesive thickness correction area moment.

6. The pre-grooved tread profile rubber for preventing asymmetric tread pattern arches according to claim 1, characterized in that, The edge of the preset groove is connected to the outer surface of the tire crown rubber layer by a rounded corner, the radius of which is 0.3mm to 1.2mm.

7. The pre-grooved tread profile rubber for preventing asymmetric tread pattern arches according to claim 1, characterized in that, The preset groove is formed by extruding the tread extrusion nozzle in one step, or by pressing it in with a pressure roller after the tread rubber is extruded, or by cutting the tread rubber after it is extruded.

8. A method for preparing a pre-grooved tread pattern rubber for preventing asymmetric tread patterns, characterized in that, The preparation method for the pre-grooved tread compound according to any one of claims 1 to 7 comprises the following steps: S1. Determine the opening width, depth, cross-sectional area, and lateral position of multiple finished tread main grooves based on the asymmetric tread pattern; S2. Determine the thickness of the base rubber layer at the designated positions of the main grooves of multiple finished tire treads, and calculate the average thickness of the base rubber layer. Base adhesive thickness correction factor and base adhesive thickness correction area moment ; S3. Adjust the area moment according to the thickness of the base adhesive. Determine the cross-sectional area, opening width, and depth of multiple preset grooves, such that the cross-sectional area of ​​the multiple preset grooves is perpendicular to the opening width and depth. Area moment with respect to the thickness of the base adhesive Same sign, and satisfy ; S4. Check the remaining tread rubber thickness of each preset groove based on the tread rubber layer thickness and the base rubber layer thickness. ; S5. Multiple preset grooves extending along the length of the tread rubber layer are formed on the outer surface of the tread rubber layer, and the multiple preset grooves are respectively located at the set positions of the main groove of the finished tread.

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