Design method of tubeless high-strength steel rim rolling process

Abstract

The present application relates to the technical field of machining, and particularly relates to a design method of a high-strength steel wheel rim rolling process without an inner tube, which is characterized in that, in the first rolling process design, a parting line of a groove bottom is designed, so that the volume of the left side of the groove bottom is less than that of the right side, and the serious material thinning of the left side is avoided; in the first rolling process design, the radius of the two side fillets of the groove top is 3mm less than the target value R, and the design value of the groove bottom depth is 5mm greater than the target value H; the second rolling process design is the same as the first rolling process design, the design value of the groove bottom depth is the same as the target value H; in the third rolling process, the radius of the left side fillet and the right side fillet of the groove top is 3mm less than the target value R, and the design value of the groove bottom depth is the same as the target value H; after the three rolling processes, the left side fillet and the right side fillet of the groove bottom reach the target value R, and the depth of the groove bottom is close to the target value H, so that the size deviation caused by the springback is avoided, and the high-strength steel wheel rim after the rolling process meets the rigidity, the bending test life and the tire assembly of the steel wheel.

Description

Technical Field

[0001] This invention relates to the field of machining technology, and in particular to a method for designing a tubeless high-strength steel wheel rim rolling process. Background Technology

[0002] The rim manufacturing process of tubeless steel wheels includes flaring, first rolling, second rolling, and third rolling. This process has the following defects: During the rolling process, due to the stretching and flow of the material, at the turning points, especially in some areas with smaller top and bottom rounded corners, the thickness will be less than the normal material thickness, and the thickness at the bottom of the groove will also be less than the normal material thickness, which is called rolling thinning.

[0003] The newly developed high-strength steel material for tubeless wheel rims for commercial vehicles has a tensile strength of Rm780~850Mpa, while the tensile strength of ordinary low-strength steel material is Rm380~450. Since the tensile strength of high-strength steel is more than twice that of low-strength steel, the springback characteristics of the wheel rim during roll forming are significantly different. Therefore, the roll forming process of high-strength steel wheel rims is significantly different from that of low-strength steel wheel rims. There is no roll forming process for high-strength steel wheel rims in the existing technology.

[0004] like Figure 1 The image shows the cross-sectional shape of a tubeless rim in the prior art. If a high-strength steel rim is processed using the traditional low-strength steel rim rolling process, when the process design values ​​of the groove top radius, groove bottom radius, and groove bottom depth are equal to the target values, the final result will be that the actual product shape deviates significantly from the specified product shape. After rolling, the groove top radius is 10% larger than the target value, and the groove bottom depth is 15.6% smaller than the target value. The size and thickness of the groove top radius and groove bottom radius affect the bending test life of the steel wheel, and the height of the groove bottom depth H affects the tire assembly and the overall rigidity of the rim.

[0005] Therefore, how to avoid localized thinning of the rim, insufficient rigidity, and short service life caused by springback deformation is an urgent problem to be solved. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a tubeless high-strength steel rim roll forming process design method. This method controls and compensates for material springback during the roll forming process and controls material flow thinning, thereby controlling product parameters and ensuring that the processed rim meets product design requirements to satisfy the rigidity, bending test life, and tire assemblability of the steel wheel.

[0007] The present invention provides a tubeless high-strength steel rim rolling process design method, the process method including preliminary process design, first rolling design, second rolling design, and third rolling design;

[0008] In the first roll forming process design, the lowest point D of the arc limit of the groove bottom of the high-strength steel rim and the parting line CC of the groove bottom were determined to make the volume of the left side of the groove bottom smaller than the volume of the right side, so as to avoid serious thinning of the material on the left side.

[0009] In the first roll forming design, the design values ​​of the radius of the left fillet RC1 and the right fillet RD1 of the groove top of the high-strength steel rim were 3mm smaller than the target value R, and the design value of the groove bottom depth was 5mm deeper than the target value H.

[0010] In the second rolling design, the design values ​​of the radius of the left fillet RC1 and the right fillet RD1 of the groove top of the high-strength steel rim are 3mm smaller than the target value R, while the design value of the groove bottom depth is the same as the target value H.

[0011] In the third rolling design, the design values ​​of the radius of the left fillet RC1 and the right fillet RD1 of the groove top of the high-strength steel rim are 3mm smaller than the target value R, while the design value of the groove bottom depth is the same as the target value H.

[0012] After three rolling processes, the radii of the left rounded corner RC1 and the right rounded corner RD1 of the groove top of the high-strength steel rim are equal to the target value R, and the groove bottom depth is 1.5mm shallower than the target value H, thus avoiding dimensional deviations caused by springback.

[0013] Preferably, the parting line CC is a vertical virtual line with the lowest point D of the arc quadrant as the horizontal direction of the high-strength steel rim, and the volume on the left side of the bottom of the parting line CC groove is smaller than the volume on the right side.

[0014] The preferred method for determining the lowest point D in the arc quadrant is as follows:

[0015] In the first roll forming process design, an experimental parting line C0-C0 is designed. In the process design, the bottom of the groove is designed as an experimental arc R0. The lowest point D0 of the quadrant of the experimental arc is the lowest point of the quadrant of the experimental arc R0. Calculate the left and right volumes of the experimental parting line C0-C0.

[0016] If the volume on the left is greater than the volume on the right, then move the experimental arc R0 to the left to the position of arc R1, move the experimental parting line C0-C0 to the rear parting line C1-C1, and move the lowest point D0 of the experimental arc quadrant to the lowest point D' of the rear arc quadrant. Then perform volume calculations until the volume on the left is less than the volume on the right, thus determining the final position of the lowest point D in the arc quadrant.

[0017] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0018] 1. By designing the values ​​of the radius of the left rounded corner RC1 and the right rounded corner RD1 of the groove top and the groove bottom depth through three rolling processes, the dimensional deviation caused by springback is avoided. The radius of the left rounded corner RC1 and the right rounded corner RD1 of the groove top reaches the target value after three rolling processes, and the groove bottom depth H is close to the target value. The target value can be reached after the expansion process, so that the rolled rim meets the rigidity of steel wheels, bending test life and tire assembly.

[0019] 2. By determining the lowest point D in the arc quadrant, the parting line CC is designed to control the volume distribution on the left and right sides, thereby ensuring that the volume on the left side of the parting line CC is smaller than the volume on the right side, thus avoiding severe thinning of the material on the left side. Attached Figure Description

[0020] Figure 1 This is a comparative diagram showing that the actual product shape in the prior art deviates significantly from the product specification;

[0021] Figure 2 This is a schematic diagram of the rolling process flow of the tubeless high-strength steel wheel rim rolling process design method provided in the embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of the method for determining the bottom volume of the CC parting groove in the tubeless high-strength steel rim rolling process design method provided in the embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the CC parting line determination method in the tubeless high-strength steel rim rolling process design method provided in the embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the positioning of the flared part in the preceding process of the tubeless high-strength steel rim rolling process design method provided in the embodiment of the present invention;

[0025] Figure 6 This is a schematic diagram of the closed pressure holding process in the preceding process of the tubeless high-strength steel rim rolling process design method provided in the embodiment of the present invention;

[0026] Figure 7 This is a schematic diagram of the left-side volume calculation of the first rolling process in the tubeless high-strength steel rim rolling process design method provided in the embodiment of the present invention;

[0027] Figure 8 This is a schematic diagram of the right-side volume calculation of the first rolling process in the tubeless high-strength steel rim rolling process design method provided in the embodiment of the present invention;

[0028] Figure 9 This is a schematic diagram of the first roll forming process total volume calculation of the tubeless high-strength steel rim roll forming process design method provided in the embodiment of the present invention;

[0029] Figure 10 This is a schematic diagram of the left-side volume calculation in the second rolling process of the tubeless high-strength steel rim rolling process design method provided in the embodiment of the present invention;

[0030] Figure 11 This is a schematic diagram of the right-side volume calculation of the second rolling process in the tubeless high-strength steel rim rolling process design method provided in the embodiment of the present invention;

[0031] Figure 12 This is a schematic diagram of the second rolling process total volume calculation of the tubeless high-strength steel rim rolling process design method provided in the embodiment of the present invention;

[0032] Figure 13 This is a schematic diagram of the third rolling process total volume calculation of the tubeless high-strength steel rim rolling process design method provided in the embodiment of the present invention.

[0033] Figure label:

[0034] Left corner fillet RC1 at the top of the groove, right corner fillet RD1 at the top of the groove, point A 5mm from the tangent point of the left corner fillet RC1 at the top of the groove, point B 5mm from the tangent point of the right corner fillet RD1 at the top of the groove, left corner fillet RC2 at the bottom of the groove, right corner fillet RD2 at the bottom of the groove, bottom depth H, parting line CC, lowest point D in the arc quadrant, calculated bottom volume range W, lowest point D0 in the experimental arc quadrant, experimental arc R0, experimental parting line C0-C0, lowest point D' in the rear arc quadrant, rear arc R1, rear parting line C1-C1, bottom depth H, upper roller M, lower roller N, flared part L. Detailed Implementation

[0035] In the following description, embodiments of the invention will be described with reference to the accompanying drawings. In the description below, the same modules are denoted by the same reference numerals. Where the same reference numerals are used, their names and functions are also the same. Therefore, their detailed description will not be repeated.

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0037] Figure 1 This illustrates that in the prior art, the actual product shape deviates significantly from the product specifications.

[0038] like Figure 1As shown in the figure, the actual product shape in the prior art deviates significantly from the product shape. The rolling process includes three steps. After the three steps, the thick solid line represents the product designed and produced according to the rolling process of low-strength steel material with high-strength steel material. As can be seen from the figure, the actual product shape deviates significantly from the product shape specified, which greatly affects the rigidity, bending test life and tire assembly of high-strength steel rims.

[0039] Figure 2 The rolling process flow of the tubeless high-strength steel rim rolling process design method provided in the embodiment of the present invention is shown.

[0040] like Figure 2 As shown in the figure, the tubeless high-strength steel rim roll forming process design method provided by the present invention includes the following steps:

[0041] S1. Preliminary process design;

[0042] In the aforementioned process design, the lowest point D of the arc limit of the groove bottom of the high-strength steel rim and the parting line CC of the groove bottom are determined to make the volume on the left side of the groove bottom smaller than the volume on the right side, thus avoiding severe thinning of the material on the left side.

[0043] S2, First Roller Design;

[0044] In the first rolling design, the design values ​​of the radius of the left rounded corner RC1 and the right rounded corner RD1 of the groove top of the high-strength steel rim are 3mm smaller than the target value R, and the design value of the groove bottom depth is 5mm deeper than the target value H.

[0045] S3, Second Rolling Design;

[0046] In the second rolling design, the design values ​​of the radius of the left rounded corner RC1 and the right rounded corner RD1 of the groove top of the high-strength steel rim are 3mm smaller than the target value R, and the design value of the groove bottom depth is the same as the target value H.

[0047] S4, Third Roller Design;

[0048] In the third rolling design, the design values ​​of the radius of the left rounded corner RC1 and the right rounded corner RD1 of the groove top of the high-strength steel rim are 3mm smaller than the target value R, while the design value of the groove bottom depth is the same as the target value H.

[0049] Figure 3 This invention illustrates a method for determining the bottom volume of the CC groove at the parting line in a tubeless high-strength steel rim rolling process provided in an embodiment of the present invention.

[0050] Figure 4 This invention illustrates a method for determining the parting line CC in the tubeless high-strength steel rim rolling process provided by an embodiment of the present invention.

[0051] like Figure 3-4As shown, the tubeless high-strength steel rim roll forming process design method provided in this embodiment of the invention is determined by the characteristics of the rim roll forming process. Figure 3 In the pressing section, the material in the long shoulder area on the left is longer than that in the short shoulder area on the right. Therefore, the long shoulder area on the left flows slowly towards the bottom of the tank, while the short shoulder area on the right flows quickly towards the bottom of the tank. Thus, during the design phase, it is necessary to design the volume of the left side to be smaller than that of the right side to avoid severe thinning in the left side area.

[0052] The purpose of the CC volume calculation comparison of the parting line is to solve the problem that the volume on the left side of the bottom of the second roll parting line is smaller than the volume on the right side, under the premise that the volume of the bottom of the groove remains unchanged, so as to avoid local accumulation and thinning of material.

[0053] Experiments have shown that if the volume design of the CC on both sides of the first rolling parting line deviates from the principle that the volume on the left side is smaller than that on the right side, although the overall volume remains unchanged, if the volume on one side is too large, it will lead to an increase in material thickness and a decrease in the radius of the rounded corner at the left rounded corner RC1 or the right rounded corner RD1 at the top of the groove, which will cause the steel wheel bending experiment to fail at the rounded corner position.

[0054] Therefore, in the first roll forming process design, an experimental parting line C0-C0 is designed. In the process design, the bottom of the groove is designed as an arc. The lowest point D0 of the experimental arc quadrant is the lowest point of the experimental arc R0 quadrant. The volumes of the left and right sides of the experimental parting line C0-C0 are calculated. If the volume of the left side is greater than the volume of the right side, then the experimental arc R0 is moved to the left to the position of arc R1, the experimental parting line C0-C0 is moved to the rear parting line C1-C1, and the lowest point D0 of the experimental arc quadrant is moved to the lowest point D' of the rear arc quadrant. The volume calculation is then performed again until the volume of the left side is less than the volume of the right side.

[0055] Under normal circumstances, the volume on the left side is 3.6%-4.2% smaller than that on the right side, which can ensure that the thinning rate of the left rounded corner RC1 and the right rounded corner RD1 of the top of the tank is controlled at 10% (industry standard). See the test results in Table 1 below.

[0056] Table 1

[0057]

[0058] Figure 5 The illustration shows the positioning of the flared part, a preliminary process in the tubeless high-strength steel rim rolling process design method provided in this embodiment of the invention.

[0059] Figure 6 The preceding process of the tubeless high-strength steel rim rolling process design method provided in the embodiment of the present invention is shown.

[0060] like Figures 5-6As shown in the embodiment of the present invention, the tubeless high-strength steel rim roll forming process design method involves the following steps in the first roll forming process: The lower roller N and the flared part L move upwards, while the upper roller M compresses the lowest point D1 of the arc quadrant of the flared part, which is theoretically also the lowest point D of the arc quadrant at the bottom of the parting line CC. Points D and D1 are the intersection points of the parting line and the flared part. The upper roller M and the lower roller N clamp the flared part L. The position of the upper roller M remains unchanged, while the lower roller N feeds according to the PLC settings of the equipment. The material on both sides of the flared part gradually enters the cavity of the lower roller N. Within one workpiece cycle time, the position of point D1 on the flared part remains unchanged, and the material on both sides continuously flows towards the area near the lowest point D of the arc quadrant. Finally, the upper and lower rollers close and maintain pressure, completing one roll forming operation.

[0061] Figure 7 The left-side volume of the first rolling process of the tubeless high-strength steel rim rolling process design method provided in the embodiment of the present invention is shown.

[0062] Figure 8 The diagram shows the right-side volume of the first rolling process of the tubeless high-strength steel rim rolling process design method provided in an embodiment of the present invention.

[0063] Figure 9 The first rolling process volume of the tubeless high-strength steel rim rolling process design method provided in the embodiment of the present invention is shown.

[0064] like Figures 7-9 As shown in the embodiment of the present invention, the tubeless high-strength steel rim rolling process design method, in the first rolling design, considering the characteristics of high material strength, poor material fluidity, and large elastic rebound, the groove bottom reserve volume of the first rolling is designed to be larger than that of the second rolling, so as to facilitate subsequent molding. The radii of the left rounded corner RC1 and the right rounded corner RD1 of the groove top are smaller than the target value R.

[0065] The specific operation is as follows: The first deformation zone at the bottom of the rolling groove is from point A to point B. Point A is 5mm from the tangent point of the left rounded corner RC1 at the top of the groove, and point B is 5mm from the tangent point of the right rounded corner RD1 at the top of the groove. Assume that the target values ​​R of RC1 and RD1 are equal, both being 20mm; assume that the target value R of the depth H of the deep groove is 32mm. (Actual product designs may vary depending on the product's components and functions).

[0066] To compensate for material rebound, the design values ​​of the radii of the left fillet RC1 and the right fillet RD1 of the top of the groove are 3mm smaller than the target value R, that is, the design values ​​of the radii of the left fillet RC1 and the right fillet RD1 of the top of the groove are 17mm. The design value of the groove bottom depth H is 5mm larger than the target value H, that is, 37mm. After rolling, the actual result is that the actual depth of the groove bottom is 5mm less than H, that is, 27mm.

[0067] This invention proposes a method for designing the parting line of the roll-formed groove bottom, rationally addressing the volume distribution between the left and right parts of the groove bottom. The parting line is a virtual line, ensuring that the rounded corners of the groove bottom and top during the secondary roll forming of the rim meet product design requirements. The volumes on the left and right sides of the parting line are automatically calculated using CAD software, such as... Figure 7 The volume of the left side region is 412931 mm². 3 Less than Figure 8 The volume of the right-side region is 446366 mm². 3 And the sum of the volumes on both sides is equal to Figure 9 The total volume after the first roll forming is 859297 mm. 3 .

[0068] Figure 10 The left-side volume of the second rolling process is shown in the rolling process design method for tubeless high-strength steel rims provided in an embodiment of the present invention.

[0069] Figure 11 The right-side volume of the second rolling process is shown in the rolling process design method for tubeless high-strength steel rims provided in an embodiment of the present invention.

[0070] Figure 12 The total volume of the second rolling process of the tubeless high-strength steel rim rolling process design method provided in the embodiment of the present invention is shown.

[0071] like Figures 10-12 As shown in the embodiment of the present invention, the tubeless high-strength steel rim rolling process design method has a second rolling design in which the storage volume of the groove bottom of the second rolling is larger than that of the third rolling.

[0072] The locations of points A and B in the deformation zone of the groove bottom during the second rolling process are the same as those during the first rolling process. The designed radii of the left fillet RC1 and the right fillet RD1 at the top of the groove are 3mm smaller than the target value R, while the designed groove bottom depth is the same as the target value H. The actual results after rolling are: the radii of the left fillet RC1 and the right fillet RD1 at the top of the groove are R, i.e., 20mm; the actual groove bottom depth, after springback, is 3mm smaller than the target value H, i.e., 29mm.

[0073] Using CAD software for automatic calculation, the total volume of the groove bottom in the second rolling process is 786937 mm². 3 Therefore, the total bottom volume of the groove for the first rolling of high-strength steel in this technical solution is 859297 mm. 3 The total bottom volume of the groove compared to the second rolling process is 786937 mm. 3The difference is 9.2%. In the existing technology, the total bottom volume of the groove in the first rolling of low-strength steel is 1.2% of the total bottom volume in the second rolling. The reason why the volume difference ratio of high-strength steel is larger is that after the bottom of the groove is rolled, the springback of high-strength steel is greater than that of low-strength steel.

[0074] Calculate the volumes on both sides of the parting line of the second rolling process and compare them. See [reference needed]. Figure 10 The volume on the left side is 384543 mm. 3 and Figure 11 The volume on the right side is 402394 mm². 3 The total volume is Figure 12 786937mm 3 This shows that after the second rolling process, the volume on the left side is still smaller than the volume on the right side, thus ensuring that the material on the left side does not undergo significant thinning.

[0075] Figure 13 The total volume of the third rolling process of the tubeless high-strength steel rim rolling process provided in the embodiment of the present invention is shown.

[0076] like Figure 13 As shown in the embodiment of the present invention, the design value of the radius of the left rounded corner RC1 and the right rounded corner RD1 of the groove top in the third rolling design is 3mm smaller than the target value R, i.e., 17mm. The design value of the groove bottom depth H is the same as the target value H.

[0077] After the third rolling process, the radii of the left rounded corner RC1 and the right rounded corner RD1 at the top of the groove are R, which is 20mm; the depth of the bottom of the groove is close to the target value H, reaching H-1.5mm, or 31.5mm. The volume of the bottom of the groove is the same as that of the second rolling process.

[0078] The reason for the final error of 1.5 is that the design value under this error meets the final thickness process requirements; if the target value H is to be achieved in the end, the value of H needs to be increased in the design stage, which will make the bottom of the tank too thin and thus fail to meet the process requirements. An error of 1.5 can achieve the same effect as the target value H in the final expansion process.

[0079] After the first, second, and third rolling processes, the circumference of the rim is 10-15mm smaller than the target final circumference. In the expansion process, the rim is plastically formed again to meet the product's process target requirements.

[0080] As shown in Table 2 below, it is assumed that the target value R of the fillet RC1 on the left side of the slot top and the fillet RD1 on the right side of the slot top are equal, both being 20mm. (Actual product designs may vary depending on the product's components and functions.)

[0081] Assume the target depth H of the deep groove is 32mm. (Actual product designs may vary depending on the product's components and functions.)

[0082] Table 2

[0083]

[0084]

[0085] The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the invention described and / or claimed herein.

[0086] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0087] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for designing a tubeless high-strength steel rim roll forming process, characterized in that, The process design method includes preliminary process design, first rolling design, second rolling design, and third rolling design; In the first rolling design, the lowest point D of the arc quadrant of the groove bottom of the high-strength steel rim and the parting line CC of the groove bottom are determined so that the volume on the left side of the groove bottom is smaller than the volume on the right side, thus avoiding severe thinning of the material on the left side. In the first rolling design, the design values ​​of the radius of the left rounded corner RC1 and the right rounded corner RD1 of the groove top of the high-strength steel rim are 1.5~3mm smaller than the target value R, and the design value of the groove bottom depth is 5~7mm deeper than the target value H. In the second rolling design, the design values ​​of the radius of the left rounded corner RC1 and the right rounded corner RD1 of the groove top of the high-strength steel rim are 3mm smaller than the target value R, and the design value of the groove bottom depth is the same as the target value H. In the third rolling design, the design values ​​of the radius of the left rounded corner RC1 and the right rounded corner RD1 of the groove top of the high-strength steel rim are 3mm smaller than the target value R, and the design value of the groove bottom depth is the same as the target value H. After three rolling processes, the radius values ​​of the left rounded corner RC1 and the right rounded corner RD1 of the groove top of the high-strength steel rim are equal to the target value R, and the groove bottom depth is 1.5mm shallower than the target value H, thereby avoiding dimensional deviations caused by springback.

2. The tubeless high-strength steel rim rolling process design method according to claim 1, characterized in that, The parting line CC is a vertical virtual line with the lowest point D of the arc quadrant and the high-strength steel rim as the horizontal direction. The volume on the left side of the bottom of the parting line CC groove is smaller than the volume on the right side.

3. The tubeless high-strength steel rim rolling process design method according to claim 1, characterized in that, The method for determining the lowest point D in the arc quadrant is as follows: In the first roll forming design, an experimental parting line C0-C0 is designed. In the process design, the bottom of the groove is designed as an experimental arc R0. The lowest point D0 of the quadrant of the experimental arc is the lowest point of the quadrant of the experimental arc R0. The left and right volumes of the experimental parting line C0-C0 are calculated. If the volume on the left side is greater than the volume on the right side, then the experimental arc R0 is moved to the left to the position of arc R1, the experimental parting line C0-C0 is moved to the rear parting line C1-C1, and the lowest point D0 of the experimental arc quadrant is moved to the lowest point D' of the rear arc quadrant. The volume is then calculated again until the volume on the left side is less than the volume on the right side, thus determining the final position of the lowest point D of the arc quadrant.

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