Boom section forming method and boom section

Abstract

Disclosed in the present invention are a boom section forming method and a boom section. In the present invention, a boom section base plate is cut according to the size of a boom section to be formed, and the boom section base plate is sequentially subjected to heating pre-bending and heating closed bending, so as to obtain a boom section only having one gap. Compared with a boom section having the same cross-section and formed by using an existing method, the strength and rigidity of the boom section can be effectively improved, the machining cost is reduced, the production efficiency is improved, and energy consumption is reduced. Compared with a boom section having the same strength and rigidity and formed by using an existing method, the cross-section size can be effectively reduced, thereby effectively reducing the weight of a boom.

Description

A method for forming a boom section and a boom section Technical Field

[0001] The invention relates to a boom section forming method and a boom section, and belongs to the field of boom section preparation. Background Art

[0002] The boom section is the core component of aerial work platforms, cranes, etc. It is the most important load-bearing structure for lifting and hoisting operations. Its strength basically determines the lifting performance of the lifting equipment. The boom section is processed and formed from sheet metal. This forming process is a very critical process in the production process of the boom and has an important impact on the mechanical properties of the boom.

[0003] In the currently disclosed technologies (such as CN103287994A, CN205076723U, CN202785400U, CN110733992A and CN103015726B), the boom sections are all made of sheet metal by bending and welding. However, there are at least two welds. During the welding process, deformation of the sheet metal is difficult to avoid. The more welds are made, the more damage is done to the sheet metal, which inevitably reduces the structural strength of the overall boom.

[0004] Summary of the Invention

[0005] The present invention provides a boom section forming method and a boom section, which solve the problems disclosed in the background technology.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A method for forming a boom section, comprising:

[0008] According to the required size of the boom section, the plate is cut to obtain the boom section base plate;

[0009] From one side to the other side of the boom section base plate, the boom section base plate is divided into a first boom section top plate portion, a first boom section side plate portion, a boom section bottom plate portion, a second boom section side plate portion and a second boom section top plate portion in sequence;

[0010] Heating and pre-bending the first portion of the boom section top plate and the second portion of the boom section top plate, so that the first portion of the boom section top plate and the second portion of the boom section top plate are bent toward each other at a preset angle A;

[0011] The first side plate portion of the boom section and the second side plate portion of the boom section are heated and pre-bent so that the first side plate portion of the boom section and the second side plate portion of the boom section are bent toward each other at a preset angle C;

[0012] The boom section base plate that has been heated and pre-bent is subjected to heating, sealing and bending to obtain a formed boom section.

[0013] The cutting plate is a high-strength aluminum alloy plate.

[0014] A fixed mold with a heating function is used to heat and pre-bend the first part of the boom section top plate and the second part of the boom section top plate.

[0015] A flexible reconfigurable mold with a heating function is used to perform multiple heating and pre-bending on the first part of the boom section top plate and the second part of the boom section top plate; each heating and pre-bending causes the first part of the boom section top plate and the second part of the boom section top plate to bend toward each other at a preset angle B, and the sum of the angles B formed by all heating and pre-bending is equal to the preset angle A; during each heating and pre-bending process, the plate body is heated and pre-bent in sections.

[0016] A flexible reconfigurable mold with a heating function is used to perform multiple heating and pre-bending on the first side plate portion and the second side plate portion of the boom section; each heating and pre-bending causes the first side plate portion and the second side plate portion of the boom section to bend toward each other at a preset angle D, and the sum of the angles D formed by all heating and pre-bending is equal to the preset angle C; during each heating and pre-bending process, the plate body is heated and pre-bent in sections.

[0017] A flexible reconfigurable mold with a heating function is used to perform multiple heating and closed bending on the boom section base plate after heating and pre-bending. Each heating and pre-bending causes the first part of the boom section top plate and the second part of the boom section top plate to bend toward each other at a preset angle E, and causes the first side plate part and the second side plate part of the boom section to bend toward each other at a preset angle F. During each heating and closed bending process, the plate body is subjected to segmented heating and closed bending.

[0018] During the segmented heating and bending process, a laser tracking and positioning method is used to align the current bending line with the previous bending line, and a multi-point laser heating method is used to heat the current bending line before bending and pressing.

[0019] During the heating and closing bending process, the bending part is wind quenched.

[0020] During the heating, closing and bending process, the mold for pressing the first part of the boom section top plate and the second part of the boom section top plate is a triangular punch, and the mold for pressing the first side plate part, the boom section bottom plate part and the second side plate part of the boom section is an arc-shaped concave mold.

[0021] A boom section is formed by the above-mentioned boom section forming method.

[0022] The beneficial effects achieved by the present invention are as follows: the present invention cuts out a boom section base plate according to the size of the boom section to be formed, and performs heating pre-bending and heating closed bending on the boom section base plate in sequence, so as to obtain a boom section with only one gap. Compared with the boom section formed by the existing method with the same cross-section, the strength and rigidity of the boom section can be effectively improved, and the processing cost can be reduced, the production efficiency can be improved, and the energy consumption can be reduced; and compared with the boom section formed by the existing method with the same strength and rigidity, the cross-sectional size can be effectively reduced, thereby achieving effective weight reduction of the boom frame. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG1 is a flow chart of a boom section forming method;

[0024] Figure 2 is a schematic structural diagram of a boom section base plate;

[0025] FIG3 is a schematic diagram of heating and pre-bending of a fixed mold in the first boom section forming method;

[0026] FIG4 is a schematic diagram of the heating and pre-bending of the flexible reconfigurable mold in the first boom section forming method;

[0027] FIG5 is a schematic diagram of the heating, closing, bending and pressing of the flexible reconfigurable mold in the first boom section forming method;

[0028] FIG6 is a schematic diagram of heating and pre-bending of a fixed mold in the second boom section forming method;

[0029] FIG7 is a schematic diagram of the heating and pre-bending of the flexible reconfigurable mold in the second boom section forming method;

[0030] FIG8 is a schematic diagram of the heating, closing, bending and pressing of the flexible reconfigurable mold in the second boom section forming method;

[0031] FIG9 is a schematic diagram of heating, closing, and bending with consideration given to the springback of the plate;

[0032] FIG10 is a schematic diagram of the plate after rebound. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0034] As shown in FIG1 , a method for forming a boom section includes the following steps:

[0035] Step 1: Cut the plate according to the required size of the boom section to obtain the boom section base plate.

[0036] Step 2, from one side of the boom section base plate to the other side, divide the boom section base plate into the first part of the boom section top plate, the first side plate part of the boom section, the bottom plate part of the boom section, the second side plate part of the boom section and the second part of the boom section top plate.

[0037] Step 3: heat and pre-bend the first portion of the boom section top plate and the second portion of the boom section top plate, so that the first portion of the boom section top plate and the second portion of the boom section top plate are bent toward each other at a preset angle A.

[0038] Step 4: heat and pre-bend the first side plate portion and the second side plate portion of the boom section so that the first side plate portion and the second side plate portion of the boom section are bent toward each other at a preset angle C.

[0039] Step 5: heating and sealing the boom section base plate after the heating and pre-bending to obtain a formed boom section.

[0040] The above method cuts out a boom section base plate according to the size of the boom section to be formed, and performs heating pre-bending and heating closed bending on the boom section base plate in sequence, so as to obtain a boom section with only one gap. Compared with the boom section formed by the existing method with the same cross-section, the strength and rigidity of the boom section can be effectively improved, and the processing cost can be reduced, the production efficiency can be improved, and the energy consumption can be reduced; and compared with the boom section formed by the existing method with the same strength and rigidity, the cross-sectional size can be effectively reduced, thereby achieving effective weight reduction of the boom frame.

[0041] At present, the lightweight design of replacing steel with aluminum has been well applied in the fields of aerospace, rail transportation, etc. In the engineering machinery industry, due to the high working strength requirements, as an embodiment of the present invention, the present invention uses high-strength aluminum alloy to prepare the boom section, that is, according to the required size of the boom section to be formed, the high-strength aluminum alloy plate is cut to obtain the boom section base plate, specifically see Figure 2, from one side to the other side of the boom section base plate, the boom section base plate is divided into the first part of the boom section top plate, the first side plate part of the boom section, the bottom plate part of the boom section, the second side plate part of the boom section and the second part of the boom section top plate; wherein, the first part of the boom section top plate and the second part of the boom section top plate will finally be spliced ​​into the boom section top plate, and generally the sizes of these two parts are the same.

[0042] Although high-strength aluminum alloy is strong and can completely replace steel, it has poor formability and is difficult to perform plastic bending and stamping. Therefore, the present invention performs flexible bending on the boom section base plate in multiple steps, which can be specifically as follows:

[0043] 1. The first part of the boom section top plate and the second part of the boom section top plate are heated and pre-bent so that the first part of the boom section top plate and the second part of the boom section top plate are bent toward each other at a preset angle A.

[0044] Generally, the pre-bending angle of the top plate is not large. For cost and efficiency reasons, a fixed mold with a heating function can be used for this pre-bending. For example, when bending a square boom section, as shown in Figure 3, a fixed mold with a heating function (i.e., a heating resistor within the mold) is used to heat and pre-bend the first and second sections of the boom section's top plate. For bending an arc-shaped boom section, as shown in Figure 6, this fixed mold bending method achieves a single-step bending process, i.e., bending to the preset angle A.

[0045] Of course, if cost and efficiency are not considered, a flexible reconfigurable mold with heating function (similar to the molds in Figures 4, 5, 7, and 8, with laser heads on both sides of the molds in the figures) can also be used to perform multiple heating and pre-bending on the first part of the boom section top plate and the second part of the boom section top plate; wherein, each heating and pre-bending causes the first part of the boom section top plate and the second part of the boom section top plate to bend toward each other at a preset angle B, and the sum of the angles B formed by all heating and pre-bending is equal to the preset angle A; and during each heating and pre-bending process, the plate body is heated and pre-bent in sections, that is, the plate body can be migrated by a migration device, bending and pressing for a section and then migrating for a section, and the plate body section downstream of the bending is pre-bent.

[0046] In order to ensure that the bending lines are aligned between multiple sections of pre-bending, the present invention adopts a laser tracking and positioning method during the segmented heating and bending process to align the current bending line with the previous bending line; and in order to facilitate bending, the present invention further adopts a multi-point laser heating method to heat the current bending line.

[0047] 2. The first side plate portion of the boom section and the second side plate portion of the boom section are heated and pre-bent, so that the first side plate portion of the boom section and the second side plate portion of the boom section are bent toward each other at a preset angle C.

[0048] The side panel heating and pre-bending adopts a flexible reconfigurable mold with heating function, see Figures 4 and 7, and performs multiple heating and pre-bending on the first side panel part of the boom section and the second side panel part of the boom section; each heating and pre-bending causes the first side panel part of the boom section and the second side panel part of the boom section to bend toward each other at a preset angle D, and the sum of the angles D formed by all heating and pre-bending is equal to the preset angle C; during each heating and pre-bending process, the plate body is heated and pre-bent in sections.

[0049] Similarly, in order to ensure that the bending lines are aligned between multiple sections of pre-bending, a laser tracking and positioning method is used during the segmented heating and bending process to align the current bending line with the previous bending line; and in order to facilitate bending, a multi-point laser heating method is further used to heat the current bending line.

[0050] 3. The boom section base plate that has been heated and pre-bent is subjected to heating, sealing and bending to obtain a formed boom section.

[0051] Similar to the heating and pre-bending of the side panels, see Figures 5 and 8, a flexible reconfigurable mold with a heating function is used to perform multiple heating and closed bending on the boom section base plate after heating and pre-bending; each heating and pre-bending causes the first part of the boom section top plate and the second part of the boom section top plate to bend toward each other at a preset angle E, and causes the first side panel part and the second side panel part of the boom section to bend toward each other at a preset angle F. After multiple heating and closed bending, the required boom section is formed, such as the square boom section in Figure 5 and the arc-shaped top panel boom section in Figure 8; in each heating and closed bending process, the plate body is subjected to segmented heating and closed bending.

[0052] Similarly, in order to ensure that the bending lines are aligned between multiple sections of pre-bending, a laser tracking and positioning method is used during the segmented heating and bending process to align the current bending line with the previous bending line; and in order to facilitate bending, a multi-point laser heating method is further used to heat the current bending line.

[0053] In order to improve the performance of the material at the bend, the bend is wind-quenched during the heated closed bending process. During the mobile heating and mobile bending process, if the bend needs to be strengthened after a certain bending is completed, it is immediately wind-quenched while the bend line still retains a certain temperature (increasing the cooling rate at a certain high temperature can improve strength) to restore the strength performance here.

[0054] It should be noted that the impact of the rebound of the plate on the final formed structure needs to be considered during the forming process, and it is necessary to consider that under greater pressure, the side plates and bottom plates of the boom section may be crushed. Therefore, during the heating closed bending process, the mold parts are adjusted, as shown in Figure 9. The mold parts for pressing the first part of the boom section top plate and the second part of the boom section top plate adopt a triangular punch, and the mold parts for pressing the first side plate part of the boom section, the boom section bottom plate part and the boom section second side plate part adopt an arc-shaped die, as shown in Figure 10. After the closed bending step is completed, the two sides and the upper flexible reconfigurable mold are separated from the formed boom section, and after the bent metal plate rebounds (the residual stress is naturally eliminated), the boom section is deformed into the final required shape.

[0055] 4. The formed boom section has only one gap, that is, the gap between the first part of the boom section top plate and the second part of the boom section top plate. The gap is welded to obtain the final boom section.

[0056] To further illustrate the above method, taking a square boom section as an example, the forming process is shown in Figures 3-5, 9-10, and includes:

[0057] S1) Based on the drawing of the square boom section, the dimensions of the high-strength aluminum alloy plate required for forming the boom section are obtained. Then, the high-strength aluminum alloy plate is cut to form a boom section base plate that is integrated, including the first portion of the boom section top plate, the first side plate portion of the boom section, the bottom plate portion of the boom section, the second side plate portion of the boom section, and the second portion of the boom section top plate of the final formed boom section, as shown in FIG2.

[0058] S2) First heating and pre-bending

[0059] Two pairs of fixed molds are used (the left punch and the left die are one pair, and the right punch and the right die are another pair, see Figure 3), and heating resistance wires are embedded in the molds.

[0060] The fixed mold is installed on the press, heated to 180°C, and the press is started, with the punch pressing downward. This pre-bending step causes plastic deformation of the sheet material at the pre-bend during the subsequent closing step. The two pairs of fixed molds used in this step can be used for all boom sections with flat top plates. The two pairs of fixed molds used in this step need to be designed based on the shape of the top plate of the boom section being formed.

[0061] S3) Second heating pre-bending

[0062] The flexible reconfigurable mold is adjusted according to the cross-sectional shape of the final formed boom section. After the shape adjustment is completed, the S) formed plate is placed in the flexible reconfigurable mold for secondary heating and pre-bending.

[0063] A heating resistance wire is embedded inside the flexible reconfigurable mold. The flexible reconfigurable mold is installed on a press and a laser gun head is installed at the same time. The two ends of the 6061-T6 high-strength aluminum alloy pre-bending forming plate are fixed on a clamping device with a traction device and a guide rail. The flexible reconfigurable mold is heated to 180°C, and the laser gun head is started (laser power 5500W, pulsed, with the forming plate partially heated to 240°C instantaneously). The traction device is started synchronously to drive the plate to be formed to move (speed 0.6m / min), and the press is started synchronously, and the mold moves back and forth (0.2m / min). The total pressing amount of this bending forming is 120mm, and the number of reciprocating tractions is 3 times. Laser heating pre-bending is completed at the boundary between the top plate and the side plate, as shown in Figure 4. This pre-bending step causes the plate to produce plastic deformation at the pre-bending point in the subsequent closing step.

[0064] S4) Heating, closing, bending and pressing

[0065] First, the upper reconfigurable module in S3) is lifted, and then the reconfigurable modules in the upper, lower, left, and right directions are adjusted; after the adjustment is completed, the left, right, and upper reconfigurable modules simultaneously perform closed bending on the plate, and the bending process is similar to S3), see Figure 5.

[0066] It should be noted that the impact of the sheet's rebound on the final formed structure needs to be considered during the forming process, and the possibility of crushing the boom section side panels and bottom panels under greater pressure needs to be considered. Therefore, when adjusting the shape of the reconfigurable mold in the closing step, as shown in Figure 9, the two side and bottom reconfigurable modules should be adjusted to a certain curvature, and the upper module should be adjusted to a conical shape so that the amount of compression gradually decreases from the middle to the two sides; in this way, after the closing bending step is completed, the two side and upper reconfigurable modules are separated from the formed boom section, and the bent metal sheet rebounds (residual stress is naturally eliminated), the boom section is deformed into the final desired shape, as shown in Figure 10.

[0067] The present invention is a novel flexible forming method which uses a rapidly reconfigurable bending die and can form boom sections of different cross-sectional shapes or lengths from high-strength aluminum alloy plates without replacing the forming equipment.

[0068] Based on the same technical solution, the present invention also discloses a boom section, which is specifically formed by the above-mentioned boom section forming method. Compared with the boom section formed by the existing method with the same cross-section, the strength and stiffness of the boom section can be effectively improved, and the processing cost can be reduced, the production efficiency can be improved, and the energy consumption can be reduced; and compared with the boom section formed by the existing method with the same strength and stiffness, the cross-sectional size can be effectively reduced, thereby achieving effective weight reduction of the boom frame.

[0069] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for forming a boom section, characterized in that: include: According to the required size of the boom section, the plate is cut to obtain the boom section base plate; From one side to the other side of the boom section base plate, the boom section base plate is divided into a first boom section top plate portion, a first boom section side plate portion, a boom section bottom plate portion, a second boom section side plate portion and a second boom section top plate portion in sequence; The first part of the boom section top plate and the second part of the boom section top plate are heated and pre-bent so that the first part of the boom section top plate and the second part of the boom section top plate are bent toward each other at a preset angle A; The first side plate portion of the boom section and the second side plate portion of the boom section are heated and pre-bent so that the first side plate portion of the boom section and the second side plate portion of the boom section are bent toward each other at a preset angle C; The heated and pre-bent boom section base plate is subjected to heated and closed bending and pressing to obtain a formed boom section.

2. The boom section forming method according to claim 1, characterized in that: The cutting plate is high-strength aluminum alloy plate.

3. The method for forming a boom section according to claim 1, characterized in that: A fixed mold with a heating function is used to heat and pre-bend the first part of the boom section top plate and the second part of the boom section top plate.

4. The method for forming a boom section according to claim 1, characterized in that: A flexible reconfigurable mold with a heating function is used to heat and pre-bend the first part of the boom section top plate and the second part of the boom section top plate for multiple times; each heating and pre-bending process causes the first part of the boom section top plate and the second part of the boom section top plate to bend toward each other at a preset angle B, and the sum of the angles B formed by all the heating and pre-bending processes is equal to the preset angle A; During each heating and pre-bending process, the plate body is heated and pre-bent in sections.

5. The method for forming a boom section according to claim 1, characterized in that: A flexible reconfigurable mold with a heating function is used to perform multiple heating and pre-bending pressing on the first side plate portion and the second side plate portion of the boom section; each heating and pre-bending pressing causes the first side plate portion and the second side plate portion of the boom section to bend toward each other at a preset angle D, and the sum of the angles D formed by all heating and pre-bending pressing is equal to the preset angle C; during each heating and pre-bending pressing process, the plate body is heated and pre-bent in sections.

6. The method for forming a boom section according to claim 1, characterized in that: A flexible reconfigurable mold with a heating function is used to perform heating, closing and bending on the boom section base plate after heating and pre-bending for multiple times; each heating and pre-bending causes the first part of the boom section top plate and the second part of the boom section top plate to bend toward each other at a preset angle E, and causes the first side plate part of the boom section and the second side plate part of the boom section to bend toward each other at a preset angle F; during each heating, closing and bending process, the plate body is heated, closed and bent in sections.

7. The method for forming a boom section according to any one of claims 4 to 6, characterized in that: In the process of segmented heating and bending, a laser tracking and positioning method is used to align the current bending line with the previous bending line, and a multi-point laser heating method is used to heat the current bending line before bending.

8. The method for forming a boom section according to claim 1, characterized in that: During the heating and closing bending process, the bending part is wind quenched.

9. The method for forming a boom section according to claim 1, characterized in that: During the heating, closing and bending process, the mold for pressing the first part of the boom section top plate and the second part of the boom section top plate is a triangular convex mold, and the mold for pressing the first side plate part of the boom section, the bottom plate part of the boom section and the second side plate part of the boom section is an arc-shaped concave mold.

10. A boom section, characterized in that: The method according to any one of claims 1 to 9 is used for forming.

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