Method for roll forming asymmetrically rolled steel strip into u-shaped skeletons

Abstract

The application discloses a kind of asymmetric rolling steel band U-shaped skeleton roll forming method, this method first determines the design reference point of final shape roller, then with the design reference point of final shape roller as foundation, using arc length invariant development method gradually develops the cross section pre-press shape of asymmetric rolling steel band U-shaped skeleton, to obtain the center line of different cross section pre-press shape in the quadrant point of long side circular arc, i.e. the design reference point of pre-press roller, using the design reference point of final shape roller and the design reference point of cross section pre-press shape to make a set of final shape roller and more than three sets of pre-press roller;Asymmetric rolling steel band U-shaped skeleton is gradually pre-pressed and formed using pre-press roller, finally using final shape roller to shape asymmetric rolling steel band U-shaped skeleton can be.The method of the application makes the steel band after forming without distortion phenomenon, can effectively reduce the use of straightening tooling, improve asymmetric rolling steel band U-shaped skeleton forming quality, reduce tooling design cost.

Description

Technical Field

[0001] This invention relates to a method for rolling asymmetric rolled steel strip U-shaped skeleton, belonging to the field of automotive sealing strip processing technology. Background Technology

[0002] See Figure 8 In automotive sealing strips, an embedded steel strip is often required as the skeleton of the sealing strip. Current U-shaped steel strips are mainly formed using equal-angle roll forming, and a straightening fixture is needed during the forming process to straighten the steel strip and reduce the twisting deformation of the skeleton. Because of the twisting of the formed skeleton, the difficulty of adjusting the extrusion die is increased, resulting in waste. This also causes the skeleton to easily deviate laterally during the sealing strip extrusion process, leading to an increase in extrusion waste. Summary of the Invention

[0003] The purpose of this invention is to provide a method for rolling asymmetric steel strip with a U-shaped skeleton, which effectively eliminates torsional strain, reduces the possibility of steel strip twisting, and improves the forming quality of the steel strip.

[0004] The technical solution of the present invention: a method for roll forming an asymmetric rolled steel strip U-shaped skeleton, comprising the following steps:

[0005] Step 1: Determine the design reference point for the final shaped roller: First, establish rolling coordinates on the CAD software. Draw the final cross-sectional shape of the asymmetric rolled steel strip U-shaped skeleton on the rolling coordinates, and make the long side and short side of the cross-section of the asymmetric rolled steel strip U-shaped skeleton located on both sides of the X-axis. Then, calculate the axis of inertia of the cross-section of the asymmetric rolled steel strip U-shaped skeleton on the CAD software, and establish the axis of inertia coordinates of the cross-section using the axis of inertia as the reference. Then, rotate the cross-section of the asymmetric rolled steel strip U-shaped skeleton along with the axis of inertia coordinates of the cross-section by the offset angle of the axis of inertia, so that the axis of inertia coordinates of the cross-section coincide with the rolling coordinates. At this time, the center line of the cross-section of the asymmetric rolled steel strip U-shaped skeleton at the quadrant point of the long side arc is taken as the design reference point for the final shaped roller.

[0006] Step 2: Based on the design reference point of the final roller, the cross-sectional pre-compression shape of the asymmetric rolled steel strip U-shaped skeleton is gradually unfolded using the arc length constant unfolding method to obtain the center line of different cross-sectional pre-compression shapes in the quadrant of the long side arc, which is the design reference point of the pre-compression roller. The cross-sectional pre-compression shapes of two adjacent times must satisfy the relationship: R1=a1 / a2*R2, where R1 and a1 represent the long side arc and the long side unfolding angle before unfolding, respectively, and R2 and a2 represent the long side arc and the long side unfolding angle after unfolding, respectively.

[0007] Step 3: Using the design reference points of the final shaped roller obtained in Step 1 and the design reference points of the pre-compression cross-section obtained in Step 2, manufacture one set of final shaped rollers and three or more sets of pre-compression rollers;

[0008] Step 3: Use pre-pressing rollers to gradually pre-press and form the asymmetrical rolled steel strip U-shaped skeleton, and finally use final forming rollers to shape the asymmetrical rolled steel strip U-shaped skeleton.

[0009] In the above methods, when making the final forming roller or pre-pressing roller, it is necessary to ensure that the long side forming angle of the U-shaped skeleton section of the asymmetrical rolled steel strip is smaller than the short side forming angle.

[0010] In the above method, the value range of the inertial axis offset angle of the cross section is 10 to 20 degrees.

[0011] In the above method, when the cross-sectional pre-compression shape of the asymmetric rolled steel strip U-shaped skeleton is gradually unfolded using the arc length constant unfolding method, non-equal angle unfolding is adopted, that is, a1≠a2, to reduce the possibility of steel strip twisting.

[0012] Because of the adoption of the above technical solution, the advantages of the present invention are as follows:

[0013] 1. Select the position where the strain on both sides of the U-shaped skeleton section of the asymmetric rolled steel strip is close as the design reference point of the final forming roller. This is used to reduce the strain difference on both sides when the asymmetric rolled steel strip U-shaped skeleton is formed, reduce the forming angle required for the long side with larger strain, and increase the forming angle required for the short side with smaller strain, thereby reducing the twisting phenomenon.

[0014] 2. The twisting and deformation of the steel strip after forming is reduced, which can effectively reduce the use of straightening tools, improve the forming quality of the U-shaped skeleton of the asymmetric rolled steel strip, and reduce tooling design costs.

[0015] 3. Because the steel strip forms a straighter skeleton compared to the old method, it is more stable when passing through the orifice positioning core, reducing the risk of skeleton skewing, reducing machine adjustment scrap, and improving product quality. Attached Figure Description

[0016] Figure 1 A schematic diagram showing the final cross-sectional shape of the asymmetric rolled steel strip U-shaped skeleton in the coordinates of the cross-section inertia axis and the rolling coordinate.

[0017] Figure 2 A schematic diagram of the cross-section of an asymmetric rolled steel strip U-shaped skeleton after the rotation of the inertial axis offset angle;

[0018] Figure 3 A schematic diagram of the cross-section of an asymmetric rolled steel strip U-shaped skeleton being gradually unfolded using the constant arc length unfolding method;

[0019] Figure 4 This is a schematic diagram of the cross-section of the asymmetric rolled steel strip U-shaped skeleton in the embodiment being gradually unfolded using the arc length constant unfolding method;

[0020] Figure 5 This is a schematic diagram of the final forming roller and pre-compression roller used to form the U-shaped skeleton of the asymmetric rolled steel strip in the embodiment.

[0021] Figure 6 A partial structural diagram of the U-shaped skeleton of the asymmetric rolled steel strip when it is flattened;

[0022] Figure 7 A partial structural diagram of the asymmetric rolled steel strip U-shaped skeleton after pre-compression forming;

[0023] Figure 8 This is a cross-sectional view of the asymmetric rolled steel strip U-shaped skeleton assembled with automotive sealing strips. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0025] An embodiment of the present invention: a method for roll forming a U-shaped skeleton of asymmetric rolled steel strip, comprising the following steps:

[0026] Step 1: Determine the design reference point for the final roller: See Figure 1 First, establish a rolling coordinate system (XY) in the CAD software. Draw the final cross-sectional shape of the asymmetric rolled steel strip U-shaped skeleton A on the rolling coordinate system (XY), ensuring that the long and short sides of the cross-section of the asymmetric rolled steel strip U-shaped skeleton A are located on opposite sides of the X-axis. Then, calculate the axis of inertia M of the cross-section of the asymmetric rolled steel strip U-shaped skeleton A in the CAD software, and establish the axis of inertia coordinate system MN based on the axis of inertia M. Next, rotate the cross-section of the asymmetric rolled steel strip U-shaped skeleton A along with the axis of inertia coordinate MN by an offset angle α. The value of the offset angle α ranges from 10 to 20 degrees. Make the axis of inertia coordinate MN coincide with the rolling coordinate system (XY). See [link to documentation]. Figure 2 At this point, the center line of the A section of the asymmetric rolled steel strip U-shaped skeleton is taken as the quadrant point of the long side arc R as the design reference point for the final shaped roller.

[0027] Step 2, see Figure 3Based on the design reference point of the final roller, the cross-sectional pre-compression shape of the asymmetric rolled steel strip U-shaped skeleton A is gradually unfolded using the arc-length constant unfolding method to obtain the center line of different cross-sectional pre-compression shapes in the quadrant of the long side arc R, which is the design reference point of the pre-compression roller. The cross-sectional pre-compression shapes of two adjacent times must satisfy the relationship: R1=a1 / a2*R2, where R1 and a1 represent the long side arc and the long side unfolding angle before unfolding, respectively, and R2 and a2 represent the long side arc and the long side unfolding angle after unfolding, respectively. When gradually unfolding the cross-sectional pre-compression shape of the asymmetric rolled steel strip U-shaped skeleton A using the arc-length constant unfolding method, non-equiangular unfolding is adopted, that is, a1≠a2, to reduce the phenomenon of steel strip twisting.

[0028] Step 3: Using the design reference points for the final forming roller obtained in Step 1 and the design reference points for the pre-compression shape of the cross-section obtained in Step 2, fabricate one set of final forming rollers and three or more sets of pre-compression rollers. To reduce the strain difference on both sides during the forming of the asymmetric roll-shear steel strip U-shaped skeleton, this embodiment uses five sets of pre-compression rollers and one set of final forming rollers to form the asymmetric roll-shear steel strip U-shaped skeleton in stages. See [link to documentation] Figure 4 Five sets of pre-compression rollers and one set of final forming rollers need to be designed according to the long and short side forming angles of the cross-section of the asymmetric rolled steel strip U-shaped skeleton A. It is necessary to ensure that the long side forming angle of the cross-section of the asymmetric rolled steel strip U-shaped skeleton A is less than the short side forming angle.

[0029] Step 3, see Figure 6 The initial state of the asymmetric rolled steel strip U-shaped skeleton A is a continuous strip structure, see [reference]. Figure 5 The asymmetrical rolled steel strip U-shaped skeleton A is gradually pre-pressed and formed using pre-pressing rollers. (See also...) Figure 7 After pre-pressing, the U-shaped skeleton A of the asymmetrical rolled steel strip is bent on both sides to form the long side and the short side; finally, the asymmetrical rolled steel strip U-shaped skeleton A is shaped by the final forming roller.

Claims

1. A method for roll forming an asymmetric rolled steel strip U-shaped skeleton, characterized in that... Includes the following steps: Step 1: Determine the design reference point for the final shaped roller: First, establish the rolling coordinate XY on the CAD software. Draw the final cross-sectional shape of the asymmetric rolled steel strip U-shaped skeleton on the rolling coordinate XY, and make the long side and short side of the cross-section of the asymmetric rolled steel strip U-shaped skeleton located on both sides of the X-axis. Then, calculate the inertia axis M of the cross-section of the asymmetric rolled steel strip U-shaped skeleton on the CAD software, and establish the cross-section inertia axis coordinate MN with the cross-section inertia axis M as the reference. Then, rotate the cross-section of the asymmetric rolled steel strip U-shaped skeleton along with the cross-section inertia axis coordinate MN by the cross-section inertia axis offset angle α, so that the cross-section inertia axis coordinate MN coincides with the rolling coordinate XY. At this time, the center line of the asymmetric rolled steel strip U-shaped skeleton cross-section at the quadrant point of the long side arc R is taken as the design reference point for the final shaped roller. Step 2: Based on the design reference point of the final roller, the cross-sectional pre-compression shape of the asymmetric rolled steel strip U-shaped skeleton is gradually unfolded using the arc length constant unfolding method to obtain the quadrant point of the center line of different cross-sectional pre-compression shapes in the long side arc (R), which is the design reference point of the pre-compression roller. The cross-sectional pre-compression shapes of two adjacent times must satisfy the relationship: R1=a1 / a2*R2, where R1 and a1 represent the long side arc and the long side unfolding angle before unfolding, respectively, and R2 and a2 represent the long side arc and the long side unfolding angle after unfolding, respectively. Step 3: Using the design reference points of the final shaped roller obtained in Step 1 and the design reference points of the pre-compression cross-section obtained in Step 2, manufacture one set of final shaped rollers and three or more sets of pre-compression rollers; Step 4: Use pre-pressing rollers to gradually pre-press and form the asymmetrical rolled steel strip U-shaped skeleton, and finally use final forming rollers to shape the asymmetrical rolled steel strip U-shaped skeleton.

2. The method for roll forming asymmetric rolled steel strip U-shaped skeleton according to claim 1, characterized in that: When making the final-shaped roller or pre-pressed roller, it is necessary to ensure that the long side forming angle of the U-shaped skeleton section of the asymmetrical rolled steel strip is smaller than the short side forming angle.

3. The method for roll forming asymmetric rolled steel strip U-shaped skeleton according to claim 1, characterized in that: The value range of the inertial axis offset angle α of the cross section is 10 to 20 degrees.

4. The method for roll forming asymmetric rolled steel strip U-shaped skeleton according to claim 1, characterized in that: When using the constant arc length unfolding method to gradually unfold the cross-sectional pre-compression shape of the asymmetric rolled steel strip U-shaped skeleton, non-equal angle unfolding is adopted, i.e., a1≠a2, to reduce the phenomenon of steel strip twisting.

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