Passage of roll bending unit, manufacturing method and roll bending unit

Abstract

The application discloses a kind of roll bending unit hole type preparation method, and the application belongs to the field of rolling bending forming, comprising: the hole curve model of plate bending forming is constructed, wherein the hole curve model includes first section, last section and intermediate section between the first section and the last section, and the intermediate section is curved convex arc section;Based on the hole curve model, the three-dimensional model of the hole type of the roll bending unit is constructed, wherein the three-dimensional model includes a pair of the hole curve model, and the first section between the pair of the hole curve model, the last section and the intermediate section are all formed gap;Based on the three-dimensional model, the hole type of the roll bending unit is prepared.Compared with conventional roll bending forming hole type design, the application can improve the strength of plate bending angle, also can reduce the stress concentration of corner, reduce the risk of crack and fracture, improve the quality requirement of plate roll bending forming, improve production efficiency, reduce cost.

Description

Technical Field

[0001] This invention belongs to the field of rolling roll bending technology, and particularly relates to a roll bending machine's die shape, preparation method, and roll bending machine. Background Technology

[0002] Roll forming is a common metal processing method that shapes sheet metal into specific shapes and sizes using a roll forming machine. The design of the roll die is a crucial component of the roll forming machine, directly determining the rationality of the production process and the quality of the roll-formed products.

[0003] Currently, the conventional roll forming die design in existing technologies easily leads to thinning at the bends, cracks at the inner and outer bends, and damage to the internal structure, reducing the strength, fatigue value, toughness, and impact resistance of the steel support structure and rectangular tube, which greatly affects the forming quality of the product.

[0004] Meanwhile, for sheet materials with different material properties to be bent, the existing technology does not clearly describe the die curve function model of the forming roller, and cannot construct a die curve model with better forming effect, which directly leads to a reduction in the production efficiency of roller bending. Summary of the Invention

[0005] This invention proposes a method for preparing the die pattern of a roll bending unit to solve the technical problems existing in the prior art. It can not only improve the strength at the corner of the plate, but also reduce the stress concentration at the corner, reduce the risk of cracks and fractures, improve the quality requirements of plate roll bending, increase production efficiency, and reduce costs.

[0006] To achieve the above objectives, the present invention provides a method for preparing the die pattern of a roll bending unit, comprising:

[0007] Construct a hole curve model for sheet metal roll bending, wherein the hole curve model includes a first segment, a last segment, and an intermediate segment located between the first segment and the last segment, and the intermediate segment is a curved and raised arc segment;

[0008] Based on the aforementioned die curve model, a three-dimensional model of the die shape of the roller bending unit is constructed, wherein the three-dimensional model includes a pair of the aforementioned die curve models, and gaps are formed between the first segment, the last segment, and the middle segment of the pair of the aforementioned die curve models.

[0009] Based on the three-dimensional model, the die shape of the roller bending unit is prepared.

[0010] The functional expression of the aperture curve model is:

[0011]

[0012] Where x1 is the starting point value of the aperture curve model on the x-axis, x2 is the starting point value of the middle segment function, x3 is the ending point value of the middle segment function, x4 is the ending point value of the aperture curve model on the x-axis, k is the slope of the first segment of the aperture curve model, -k is the slope of the last segment of the aperture curve model, f1 and f2 are the intercepts of the aperture curve model on the y-axis, and a1, a2, a3, b1, b2, b3, c1, c2, and c3 are coefficients.

[0013] Preferably, the value of k in the function of the first segment and the last segment is determined by the yield strength and the elastic modulus.

[0014] Preferably, the value of the coefficient is determined by the bending radius, plate width, and plate thickness.

[0015] Preferably, the aperture curves of the pair of aperture curve models are parallel.

[0016] To achieve the above-mentioned technical objectives, the present invention also provides a die pattern for a roller bending unit, which is prepared by a method for preparing the die pattern of a roller bending unit.

[0017] Preferably, it includes a first aperture segment and a second aperture segment prepared based on a pair of aperture curve models respectively.

[0018] To achieve the above-mentioned technical objectives, the present invention also provides a roller bending unit, including the die type of the roller bending unit.

[0019] Compared with the prior art, the present invention has the following advantages and technical effects:

[0020] This invention proposes a method for preparing the die shape of a roll bending machine. It constructs a die shape curve model for roll bending of sheet metal. The die shape curve model includes a first segment, a last segment, and an intermediate segment located between the first and last segments. The intermediate segment is a curved, raised arc segment. Furthermore, using the die shape curve model, a three-dimensional model of the die shape of the roll bending machine is constructed. The three-dimensional model includes a pair of the die shape curve models, with gaps formed between the first segment, the last segment, and the intermediate segment of the pair. This invention's technical solution can more accurately target sheet metal with different material properties for roll bending, constructing a die shape curve model with better forming effect based on the die shape curve function model. This is more conveniently applicable to enterprises producing sheet metal of different materials and sizes for roll bending, improving production efficiency, reducing costs, and simultaneously increasing the strength at the bends of the sheet metal, reducing stress concentration at the corners, lowering the risk of cracks and fractures, thereby improving the forming quality of the sheet metal.

[0021] This invention also provides a die pattern for a roll bending unit, which is prepared by a method for preparing the die pattern of a roll bending unit. Compared with the traditional roll bending die pattern design, this invention effectively solves the problems of steel support structure and rectangular tube production in the current roll bending forming technology, and provides a better die pattern design method and technical support for the industrialization of large-scale production of rectangular tube roll bending forming. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0023] Figure 1 This is a flowchart illustrating an embodiment of the present invention;

[0024] Figure 2 This is a curve diagram of the "Ω" aperture shape according to an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of a three-dimensional model of the "Ω" forming roller according to an embodiment of the present invention;

[0026] Figure 4 This is a diagram showing the perforation curves of the upper and lower forming rollers of the "Ω" shape in an embodiment of the present invention.

[0027] Figure 5 This is an Ω-shaped hole curve diagram of a magnesium alloy sheet with a bending radius of 10mm, according to an embodiment of the present invention.

[0028] Figure 6 This is an Ω-shaped hole curve diagram of a magnesium alloy sheet with a bending radius of 6mm, according to an embodiment of the present invention.

[0029] Figure 7 This is an Ω-shaped hole curve diagram of Q345 steel plate with a bending radius of 10mm according to an embodiment of the present invention;

[0030] Figure 8 This is a schematic diagram of the next pass hole profile forming angle α in an embodiment of the present invention;

[0031] Figure 9 This is a schematic diagram illustrating the thickness variation of a unit at the center of the bend of the sheet metal using the "Ω" forming roller in an embodiment of the present invention.

[0032] Figure 10 This is a schematic diagram illustrating the variation in thickness of a unit at the center of a bend in a conventional forming roller sheet according to an embodiment of the present invention.

[0033] Among them, 1. "Ω" die curve; 2. "Ω" upper forming roller; 3. "Ω" lower forming roller; 4. "Ω" upper forming roller curve; 5. "Ω" lower forming roller curve; 6. "Ω" die curve for magnesium alloy sheet with a bending radius of 10mm; 7. "Ω" die curve for magnesium alloy sheet with a bending radius of 6mm; 8. "Ω" die curve for Q345 steel sheet with a bending radius of 10mm; 9. Die curve diagram of the next forming roller. Detailed Implementation

[0034] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0036] Example 1

[0037] like Figure 1 As shown, this embodiment provides a method for preparing the die pattern of a roll bending unit, including:

[0038] Step 1: Based on the laws of metal fluidity, the principle of constant volume, the theory of roll forming and the theory of die design, and considering factors such as the bending radius, plate thickness, plate width, elastic modulus and yield strength that affect the die curve, a piecewise “Ω” die curve function model is proposed.

[0039] Step 2: By using the "Ω" orifice curve function model of the present invention, the "Ω" orifice curve 1 under different working conditions can be obtained, such as... Figure 2 As shown, three-dimensional models of different “Ω” upper forming roller 2 and “Ω” lower forming roller 3 are established, as follows: Figure 3 As shown.

[0040] As attached Figure 4 As shown, the three-dimensional model includes a pair of aperture curve models. Gaps are formed between the first segment, the last segment, and the middle segment of the pair of aperture curve models. The pair of aperture curve models are the upper forming roller aperture curve of “Ω” and the lower forming roller aperture curve of “Ω”. The raised arc segment in the middle of the upper and lower forming roller aperture curves of “Ω” has a large gap. When the sheet metal is rolled and formed under heating conditions, the metal material is guided to the corner area by squeezing the metal sheet from both sides, thereby thickening the corner and improving the corner strength.

[0041] In this embodiment, the piecewise “Ω” aperture curve function model in step S1 includes: x1 is the starting point value of the “Ω” aperture curve on the x-axis, x4 is the ending point value, the first segment function is y = kx + f1, the last segment function is y = -kx + f2, k is the slope of the first segment of the aperture curve, f1 and f2 are the intercepts of the curve function on the y-axis, when the starting point of the curve is the origin, f1 is 0, and the piecewise “Ω” aperture curve function model is Equation (1):

[0042]

[0043] In the formula, k, f1, f2, a1, a2, a3, b1, b2, b3, c1, c2, and c3 are coefficients, which are determined based on factors such as bending radius, plate thickness, plate width, elastic modulus, and yield strength.

[0044] In the segmented "Ω" orifice curve function model of step S1, the k values ​​of the first and last segments of the function have upper limits. The upper limit value is the tangent of the angle α between the hypotenuse of the next forming roller orifice curve 9 and the horizontal baseline. Figure 8 As shown, as the plate thickness increases, the central angle corresponding to the arc segment of the "Ω" die curve 1 also increases, and the coefficients in the curve function model also change accordingly. The "Ω" die curve 1 also changes, that is, the "Ω" upper forming roller 2 and the "Ω" lower forming roller 3 also change accordingly.

[0045] In this embodiment, step S2 includes: obtaining "Ω" die curve 1 under different working conditions using the "Ω" die curve function model according to the present invention, and establishing different three-dimensional models of "Ω" forming rollers. In the present invention, the upper forming roller curve 4 and the lower forming roller curve 5 of "Ω" are consistent, that is, the radius of the arc portion of the two die curves is the same, and the two die curves are parallel, but the rotation directions of the two die curves are different when establishing the three-dimensional model. The "Ω" die curve 1 mentioned in the present invention refers to the upper "Ω" die curve 4.

[0046] The technical solution described in this embodiment includes the following experiments:

[0047] Experiment 1: Using AZ31B magnesium alloy sheet with dimensions of 76mm*1000mm*2mm, the yield strength, elastic modulus, specific heat, coefficient of thermal expansion, and thermal conductivity of the sheet varied at different temperatures. At room temperature, the yield strength of the sheet was 188 MPa, and the elastic modulus was 44.8 GPa. The spacing between adjacent working rolls in the roll bending unit was 480mm, the roll gap was 2mm, and the bending radius was 10mm. Using the "Ω" die curve function model proposed in this invention, the "Ω" die curve 6 with a bending radius of 10mm for the magnesium alloy sheet was obtained, as shown in Figure 6. Figure 5As shown, in actual manufacturing processes, the bending radius of the sheet metal is not a constant value. Therefore, the above parameters are only for the embodiments. When the bending radius is 6mm, the "Ω" shaped curve 7 with a bending radius of 6mm is obtained for the magnesium alloy sheet metal, as shown. Figure 6 As shown.

[0048] Experiment 2: The "Ω" hole profile curve varies depending on the material used. For materials with high yield strength and high elastic modulus, such as Q345 steel plate with dimensions of 76mm*1000mm*2mm, the yield strength at room temperature is 345MPa, the elastic modulus is 210Gpa, and the bending radius is 10mm. Using the "Ω" hole profile curve function model proposed in this invention, the "Ω" hole profile curve 8 for Q345 steel plate with a bending radius of 10mm is obtained, as shown in Figure 8. Figure 7 As shown.

[0049] Experiment 3: Using an "Ω" shaped curve with a bending radius of 10mm on magnesium alloy sheet, an "Ω" forming roller and a conventional forming roller were established and verified in simulation, including the following steps:

[0050] Simulation models were established in Abaqus using both the "Ω" forming roller and a conventional forming roller, and simulation experiments were conducted. The characteristics included the following steps: First, a three-dimensional model of the forming roller was established in Solidworks software based on the die profile curve, and then imported into Abaqus software. The material properties of AZ31B magnesium alloy sheet included: elastic modulus, Poisson's ratio, yield stress, plastic strain, specific heat, coefficient of thermal expansion, and thermal conductivity at 25°C, 125°C, 150°C, 175°C, and 200°C; the sheet size was 76mm*1000mm*2mm; the spacing between adjacent working rollers in the roll bending unit was 480mm, and the roller gap was 2mm. During the assembly of the roll bending forming unit, the downhill method should be considered, and the height at each bend should be reduced sequentially to prevent longitudinal bending and warping of the sheet during the roll bending forming process.

[0051] The sheet metal component is divided into meshes according to different regions, with reduced integral C3D8R solid elements of 2*4mm on both sides and 2*2mm in the middle corner area. The forming roller component is also divided into meshes according to different regions, with elements of 4mm on both sides and 2mm in the corner area where it contacts the sheet metal. Dynamic display analysis is used, which includes two analysis steps. The first analysis step sets a downward pressure of 0.04mm on the upper roller of the forming roller for the first pass. The second analysis step sets the working roller to rotate and the sheet metal to advance, completing the sheet metal roll bending forming.

[0052] A comparison was made between simulations using an "Ω" forming roller and a conventional forming roller. Multiple sets of unit thickness data at the center of the bend after the sheet material was rolled were extracted in the Abaqus post-processor for analysis and comparison. (See attached image.) Figure 9 The thickness of the unit at the bend of the sheet metal formed using the "Ω" forming roller shown is 2.1255 mm, as shown in the attached figure. Figure 10 As shown, the unit thickness at the bend of the sheet metal formed by conventional work roller bending is 1.927 mm. Comparing the simulation data of the two sets of experiments, it can be concluded that the "Ω" forming roller established by the "Ω" hole curve function model according to the present invention can achieve corner thickening.

[0053] The beneficial effects of this embodiment:

[0054] This invention proposes a segmented "Ω" die curve function model. For different influencing factors such as bending radius, plate thickness, plate width, elastic modulus and yield strength, a suitable "Ω" die curve can be calculated according to the function model, which can then be applied to roll forming production of different materials and sizes, and has good applicability.

[0055] Using this function model, we can obtain the "Ω" aperture curve 1 and establish the "Ω" forming roller, thereby achieving the goal of thickening the corner of the sheet metal roll forming and improving the quality requirements of sheet metal roll forming. This can greatly improve the production efficiency of enterprises, reduce costs, and create more economic benefits.

[0056] Compared with traditional roll forming die design, this invention effectively solves the problems of steel support structure and rectangular tube production in current roll forming technology, and provides a better die design method and technical support for the industrialization of large-scale production of rectangular tube roll forming.

[0057] Example 2

[0058] This embodiment provides a die pattern for a roller bending unit, which is prepared using the die pattern preparation method of the roller bending unit in Embodiment 1.

[0059] The die shape of the roll bending unit includes a first die surface segment and a second die surface segment prepared based on a pair of die shape curve models respectively;

[0060] The first hole segment is an "Ω" upper forming roller hole curve, and the second hole segment is an "Ω" lower forming roller hole curve.

[0061] Example 3

[0062] This embodiment provides a roller bending unit, including the die type of the roller bending unit described in Embodiment 2.

[0063] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for preparing the die pattern of a roll bending unit, characterized in that, include: Construct a hole curve model for sheet metal roll bending, wherein the hole curve model includes a first segment, a last segment, and an intermediate segment located between the first segment and the last segment, and the intermediate segment is a curved and raised arc segment; Based on the aforementioned die curve model, a three-dimensional model of the die shape of the roller bending unit is constructed, wherein the three-dimensional model includes a pair of the aforementioned die curve models, and gaps are formed between the first segment, the last segment, and the middle segment of the pair of the aforementioned die curve models. Based on the three-dimensional model, the die shape of the roller bending unit is prepared; The functional expression of the aperture curve model is: Where x1 is the starting point value of the aperture curve model on the x-axis, x2 is the starting point value of the middle segment function, x3 is the ending point value of the middle segment function, x4 is the ending point value of the aperture curve model on the x-axis, k is the slope of the first segment of the aperture curve model, -k is the slope of the last segment of the aperture curve model, f1 and f2 are the intercepts of the aperture curve model on the y-axis, and a1, a2, a3, b1, b2, b3, c1, c2, and c3 are coefficients.

2. The method for preparing the die pattern of the roll bending unit according to claim 1, characterized in that, The k value in the function of the first segment and the last segment is determined by the yield strength and elastic modulus of the sheet material to be rolled and formed.

3. The method for preparing the die pattern of the roll bending unit according to claim 1, characterized in that, The value of the coefficient is determined by the bending radius, plate width, and plate thickness.

4. The method for preparing the die pattern of the roll bending unit according to claim 1, characterized in that, The aperture curves of the pair of aperture curve models are parallel.

5. A die type for a roller bending unit, characterized in that, It is prepared by the method for preparing the die of the roller bending unit according to any one of claims 1-4.

6. The die profile of a roll bending unit according to claim 5, characterized in that, This includes a first aperture segment and a second aperture segment prepared based on a pair of aperture curve models.

7. A roller bending unit, characterized in that, The die type of the roller bending unit as described in any one of claims 5-6.

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