CN108787904B

CN108787904B - Stamping and riveting integrated process and die for patch reinforcing structure

Info

Publication number: CN108787904B
Application number: CN201810581277.6A
Authority: CN
Inventors: 胡志力; 华林; 王旭; 詹博异; 李岩
Original assignee: Wuhan University of Technology WUT
Current assignee: Wuhan University of Technology WUT
Priority date: 2018-06-07
Filing date: 2018-06-07
Publication date: 2020-04-21
Anticipated expiration: 2038-06-07
Also published as: CN108787904A

Abstract

The invention discloses a stamping and riveting integrated process and a die for a patch reinforcing structure, wherein the process comprises the following steps: 1. placing the patch board at a preset position of the mainboard, and fixedly connecting the patch board with the mainboard; 2. placing the patch board and the main board which are connected into a whole in a die, wherein the die integrates the functions of stamping and riveting; 3. firstly, starting a stamping function of a die to punch and form the patch board and the main board, and then starting a riveting function of the die to rivet the patch board on the main board; 4. and carrying out subsequent treatment on the patch board and the main board which are riveted into a whole to obtain the patch reinforcing structure. The invention integrally forms the main board and the patch board, reduces the input quantity of stamping dies, lowers the tool development cost, simplifies the working procedures, combines the stamping forming and the riveting, realizes the multifunctional requirement of a single die, avoids the defects of insufficient solder, coating extrusion, solder joint cracking and the like caused by welding, and can obtain a formed part with better rigidity and mechanical strength.

Description

Stamping and riveting integrated process and die for patch reinforcing structure

Technical Field

The invention belongs to the technical field of punch forming, and particularly relates to a stamping and riveting integrated process and a die for a patch reinforcing structure.

Background

In the production process of automobiles, part of automobile body parts require to improve the mechanical strength of parts in local areas, and the parts produced by the traditional part forming process have the same integral strength, so that the aim of improving the local strength cannot be fulfilled, and the strength requirement of the whole automobile cannot be met. For example, in the processing of automobile covering parts, the excessive thinness of the covering part plate can lead to insufficient rigidity and instability, or flutter occurs in a flow field to cause accidents, and the excessive thickness of the plate can lead to the increase of weight and cost.

It is a common practice at present to use patch panels in conjunction with sheet materials to increase the stiffness, stability and mechanical strength of parts. However, in the conventional patch board connection process, parts are formed and then welded, and the process has the following defects:

1. due to the influence of surface impurities such as a plating layer and the like, cold joint is easy to occur, so that the quality problems of substandard welding strength and the like are caused;

2. because most of the existing stamping forming processes are single-plate forming, two or more parts are formed separately and then are fixedly attached together through spot welding, the process needs a plurality of working procedures to finish one finished part, the required time is long, the working procedures are complicated, the tool investment is large, the cost is high, and great contrast exists between the process and the requirements of large-batch production of automobiles.

If two steel plates with different shapes and sizes are welded firstly and then integrally punched, the method is easy to have the problems of insufficient welding points, extrusion of a plating layer, pulling crack of the welding points and the like.

Disclosure of Invention

The invention aims to provide a stamping and riveting integrated process and a die for a patch reinforcing structure, which can successively realize the stamping forming and riveting of a patch board and a main board in the same die, can quickly realize the stable connection of the patch board and has low cost.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a stamping and riveting integrated process of a patch reinforcing structure comprises the following steps:

1. placing the patch board at a preset position of the mainboard, and fixedly connecting the patch board with the mainboard;

2. placing the patch board and the main board which are connected into a whole in the step 1 into a die, wherein the die integrates the functions of stamping and riveting;

3. in the die assembly process, the stamping function of the die firstly performs integrated punch forming on the patch board and the main board, then pressure maintaining is performed in the die, and meanwhile the riveting function of the die rivets the formed patch board on the formed main board;

4. and (4) carrying out subsequent processing on the patch board and the main board which are riveted into a whole in the step (3) to obtain the patch reinforcing structure.

According to the technical scheme, in the step 1, the preset position between the patch board and the main board is a position which plays a role in strengthening after the main board and the patch board are molded into a specific shape, and the fixed position between the patch board and the main board corresponds to the riveting position between the patch board and the main board.

According to the technical scheme, in the step 3, the punch forming is hot stamping forming or cold stamping forming, and the riveting is hot riveting or cold riveting.

According to the technical scheme, if the punch forming is the hot punch forming, the step 3 comprises the following steps:

301. firstly, heating a mould to a specified temperature;

302. then heating the main board and the patch board to a specified temperature;

303. and then the patch board and the main board are subjected to punch forming and riveting in a high-temperature die.

According to the technical scheme, in the step 4, the subsequent treatment comprises pressure maintaining quenching in the die and shot blasting, aging or acid pickling outside the die.

Correspondingly, the invention also provides a stamping and riveting integrated die of the patch reinforcing structure, which is used for realizing the stamping and riveting integrated process of the patch reinforcing structure.

According to the technical scheme, the end part of the riveting male die, which is close to the riveting female die, is provided with a self-locking angle bulge.

According to the technical scheme, the stamping male die and the stamping female die are internally provided with local heating and cooling mechanisms.

According to the technical scheme, the number of the riveting male dies is one or more.

The invention has the following beneficial effects: compared with the traditional welding technology, the riveting has great advantages in the aspects of dynamic strength, safety, environmental protection, connection efficiency and the like, so that the process fixed connection of the patch board and the main board is realized by adopting riveting instead of traditional welding, and a patch reinforcing structure with better rigidity and mechanical strength can be obtained; moreover, as the punching process and the riveting process are simultaneously combined in the one-time die assembly process, the punched patch board and the main board not only realize the mutual restraint and positioning in the riveting process, but also have the functions of strengthening and restraining the rebound in the in-die riveting process; in addition, the punch forming and the riveting are carried out in the same set of die, so that the investment quantity of the die can be reduced, the tool development cost is reduced, the working procedure is simplified, and the multifunctional requirement of a single die is met.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic structural view of an integrated stamping and riveting die for a patch reinforcing structure provided by the present invention;

FIG. 2 is a schematic view of the connection of the patch panel to the motherboard before stamping;

FIG. 3 is a schematic structural view of the patch panel riveted with the main board;

fig. 4 is a schematic view of a mechanism of the riveting punch in the embodiment of the invention.

In the figure: the method comprises the following steps of 1-telescopic guide rod, 2-stamping male die, 3-patch plate, 4-stamping female die, 5-lower die mounting plate, 6-upper die mounting plate, 7-hydraulic cylinder, 8-riveting male die, 9-self-locking angle protrusion, 10-main plate and 11-riveting female die.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In a preferred embodiment of the present invention, a process for integrating stamping and riveting a patch reinforcing structure comprises the following steps:

1. as shown in fig. 2, the patch board 3 is placed at a preset position of the motherboard 10 and is fixedly connected with the motherboard, specifically, the patch board is fixed with the motherboard by spot welding, so as to prevent the patch board from deviating during the transferring process;

2. as shown in fig. 1, the patch board and the main board which are connected into a whole in the step 1 are placed in a die, and the die integrates the functions of stamping and riveting;

3. the stamping function of the die firstly performs punch forming on the patch board and the main board in the die assembly process, then performs intra-die pressure maintaining, and the riveting function of the die rivets the formed patch board on the formed main board;

4. and (3) carrying out subsequent treatment on the patch board and the main board which are riveted into a whole in the step (3) to obtain the patch reinforcing structure shown in the figure 3, wherein the subsequent treatment comprises pressure maintaining quenching in the mould and shot blasting, aging or acid pickling outside the mould.

In a preferred embodiment of the present invention, the predetermined position between the patch panel and the main board is a position which has a reinforcing effect after the main board and the patch panel are molded into a specific shape, and the fixing position between the patch panel and the main board corresponds to the riveting position between the patch panel and the main board.

In a preferred embodiment of the invention, the stamping is hot stamping or cold stamping and the riveting is hot riveting or cold riveting.

If the punch forming is the hot punch forming, the step 3 comprises the following steps:

301. firstly, heating a mould to a specified temperature;

302. heating the main board and the patch board to a specified temperature, wherein the temperature of the riveting part of the main board and the temperature of the rest parts of the main board can be isothermal or gradient;

303. and then, carrying out punch forming and riveting on the patch board and the main board in the high-temperature die in sequence, wherein the riveting is carried out in a non-nail or nail gradient temperature manner.

Correspondingly, the invention also provides a stamping and riveting integrated die of the patch reinforcing structure, which is used for realizing the stamping and riveting integrated process of the patch reinforcing structure, as shown in figure 1, the die comprises an upper die mounting plate 6 and a lower die mounting plate 5 which are arranged oppositely up and down, a telescopic guide rod 1 for connecting the upper die mounting plate and the lower die mounting plate, a stamping male die 2 arranged on the upper die mounting plate 6, a stamping female die 4 arranged on the lower die mounting plate 5, a riveting male die 8 arranged in the stamping male die 2, a riveting female die 11 arranged on the surface of the stamping female die 4 and matched with the riveting male die 8, a first driving mechanism (generally, the first driving mechanism is a press machine) for driving the stamping male die to move up and down and a second driving mechanism (in the embodiment, the second driving mechanism adopts a hydraulic cylinder 7) for driving the riveting male die, wherein, the driving mechanisms of the riveting male die 11 and the stamping male die 2 can share one set of power system.

The riveting male die and the riveting female die are positioned at the joint of the patch board and the main board, after punch forming, the patch board is pre-compacted by utilizing the pressure of the closed die, the riveting male die is driven by the hydraulic cylinder to move downwards, the patch board and the main board generate plastic deformation, and the riveting female die is filled, so that riveting is completed.

In the preferred embodiment of the invention, as shown in fig. 4, the end part of the riveting male die 8 close to the riveting female die is provided with a self-locking angle protrusion 9 which can strengthen the deformation, namely performing secondary riveting. The volume of the bulge is smaller than that of the riveting male die, the position and the number of the bulge are determined according to the processing requirement of a specific processing workpiece, and the second strengthening effect is achieved. In the processing process, the bulge and the riveting male die simultaneously act on the plate, so that the plastic deformation of the plate is promoted, and the connection strength can be enhanced.

In a preferred embodiment of the invention, as shown in fig. 1, a local heating and cooling mechanism is provided in both the stamping punch and the stamping die.

In the preferred embodiment of the present invention, as shown in fig. 1, the number of the riveting punches is one or more, and a plurality of riveting can be performed. The number and the position of the riveting male dies can be adjusted according to different processing requirements of different workpieces.

If the patch reinforcing structure needs to be formed by hot stamping, a stamping and riveting integrated process of the patch reinforcing structure comprises the following steps:

(1) pretreatment: preprocessing the main board and the patch board, wherein the patch board is prefabricated into a structure which can be completely attached to the main board and can be transferred into a mold together;

(2) positioning a patch board: placing the patch board at a position to be reinforced on the main board, and fixing the patch board by using spot welding and other modes;

(3) firstly heating a mould to a specified temperature, then transferring the main board and the patch board together into a heating furnace to be heated to the specified temperature (the specified temperature is determined according to specific materials of the patch board and the main board, such as aluminum alloy to be heated to 100-, after the riveting procedure is finished, the riveting male die returns to the initial state for next processing;

(4) and (3) post-treatment: and performing subsequent treatment as required.

In the step (3), the stamping and riveting process needs to perform stamping, pressure maintaining and riveting according to a specific pressure curve so as to prevent the plate from rebounding and ensure that the riveted joint is completely shaped. The specific pressure curve refers to an optimized process curve, and a molding and riveting process curve without defects is guaranteed. The pressure curve and the pressing speed of the stamping male die used in the pressure maintaining process can be adjusted according to different materials.

The principle of the riveting process is that plastic deformation of metal is utilized, but the plasticity of the metal is usually not high under the normal temperature condition, so that the neck of the joint is easily broken due to insufficient material shaping during riveting, and the connection fails.

And (3) if the patch reinforcing structure needs to be formed by cold stamping, the difference lies in that the main board and the patch board are directly transferred into the die together without heating the die and the board in the step (3), and then are subjected to stamping forming and riveting in sequence, and are taken out after pressure maintaining is finished and then are subjected to post-treatment.

The invention is further explained by a patch reinforcing structure formed by aluminum alloy plates of 6082 series of main plates and patch plates, and the forming process comprises the following steps:

(1) pretreatment: preprocessing the main board and the patch board;

(2) positioning a patch board: placing the patch board at a preset position of the main board, and fixing the patch board and the main board in a spot welding mode;

(3) heating a mould: heating the die to 20-30 ℃;

(4) heating a metal blank: heating the main board and the patch board to 500 ℃;

(5) hot stamping and forming and in-mold riveting: transferring the main board and the patch board into a die, starting a press machine, controlling the descending speed of the press machine, performing punch forming on the board, starting a hydraulic cylinder to drive a riveting male die to descend under the closed state of the die to complete riveting, and maintaining the pressure for 10-15 seconds;

(6) quenching in a die: rapidly cooling and taking out the hot stamping part at the quenching temperature in a die;

(7) and (3) post-treatment: post-treatment such as shot blasting and finishing is performed as necessary.

It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.

Claims

1. A stamping and riveting integrated process of a patch reinforcing structure is characterized by comprising the following steps:

3. in the die assembly process, the stamping function of the die firstly performs integrated stamping forming on the patch board and the main board, then performs intra-die pressure maintaining, and meanwhile, the riveting function of the die rivets the formed patch board on the formed main board, wherein the stamping forming is hot stamping forming, and the riveting is hot riveting;

2. The stamping and riveting integrated process of a patch reinforcement structure as claimed in claim 1, wherein in step 1, the preset position between the patch board and the main board is a position which has a reinforcement effect after the main board and the patch board are molded into a specific shape, and the fixed position between the patch board and the main board corresponds to the riveting position between the patch board and the main board.

3. The integrated stamping and riveting process of a patch reinforcement structure according to claim 1, wherein step 3 comprises the steps of:

301. firstly, heating a mould to a specified temperature;

4. The integrated stamping and riveting process of a patch reinforcing structure according to claim 1, wherein in step 4, the post-processing comprises in-mold dwell quenching and out-mold shot blasting, aging or acid pickling.

5. A stamping and riveting integrated die of a patch reinforcing structure is used for realizing the stamping and riveting integrated process of the patch reinforcing structure according to any one of claims 1 to 4, and is characterized by comprising an upper die mounting plate and a lower die mounting plate which are arranged oppositely from top to bottom, a telescopic guide rod for connecting the upper die mounting plate and the lower die mounting plate, a stamping male die arranged on the upper die mounting plate, a stamping female die arranged on the lower die mounting plate, a riveting male die arranged in the stamping male die, a riveting female die arranged on the surface of the stamping female die and matched with the riveting male die, a first driving mechanism for driving the stamping male die to move up and down and a second driving mechanism for driving the riveting male die to move up and down, wherein a self-locking angle protrusion is arranged at the end part of the riveting male die, which is close to.

6. The integrated stamping and riveting die for a patch reinforcing structure according to claim 5, wherein the stamping male die and the stamping female die are each provided with a local heating and cooling mechanism.

7. The integrated stamping and riveting die for a patch reinforcing structure according to claim 5, wherein the number of riveting male dies is one or more.