Laser welding tire mold clamp mechanism and method of use

Abstract

The application provides a laser welding tire mold clamp mechanism and a use method, which comprises an upper plate, a lower plate, an upper tire mold and a clamp assembly. The upper plate is opposite to the lower plate, and a welding seam is formed at the abutting position. Above the welding seam, the upper plate and the lower plate form a "C" shaped area. The upper tire mold is located in the "C" shaped area, and a gap is left between the upper end of the upper tire mold and the upper plate, and the lower end of the upper tire mold presses the upper plate. A plurality of clamp assemblies are sequentially abutted along the length direction of the welding seam, are installed in the "C" shaped area, are fixedly connected with the upper tire mold, and one end of each clamp assembly presses the upper plate. The clamp assembly is designed for the "C" shaped area, and then the clamp assembly is installed in the upper tire mold. When the upper plate is attached to the lower plate, the movement of the upper tire mold can be controlled, so that the clamp assembly filled in the "C" shaped area can press the upper plate at one time, the segmented clamping mode of the clamping cylinder of the traditional welding fixture is replaced, the structure is simple and reliable, and the movement beat time of the clamp is greatly reduced.

Description

Technical Field

[0001] This invention belongs to the field of body-in-white welding technology, and specifically relates to a laser welding tire mold fixture mechanism and its usage method. Background Technology

[0002] The main connection processes for the hood of a traditional body-in-white are spot welding, self-piercing riveting, and hemming. For steel bodies, spot welding and hemming are generally used, while for aluminum bodies, self-piercing riveting and hemming are generally used.

[0003] Traditional automotive hood connections typically employ resistance spot welding or self-piercing riveting for initial fixing, followed by a rolling process to join the inner and outer panels. The rolling process mainly consists of pre-rolling and final rolling, which places significant demands on the flange dimensions and bending angles of the overlapping panels.

[0004] Laser welding is mainly used for welding automotive body frame structures, such as the four doors, hood, and rear cover. Traditional resistance spot welding has been gradually replaced by laser welding. Using laser welding can improve the flexibility of product design, reduce the overlap between panels, lower manufacturing costs, and at the same time improve production efficiency and increase the strength of body connections.

[0005] Traditional laser welding of car bodies uses a cylinder to drive a pressure block to press the overlapping surfaces of the plates together, ensuring the accuracy of the position between the upper and lower plates, controlling the gap during welding, and thus obtaining better welding quality.

[0006] However, traditional laser welding of car bodies is mostly used for welding the four-door frame and lap joints of the inner and outer panels of the front and rear hoods. These lap joints share a common feature: there is sufficient space above the welding position, with no sheet metal obstructing the view, facilitating the placement of clamping units. But for the outer panel sub-assembly of the car body, the weld seam is located within a narrow "C"-shaped space, with the longest weld seam exceeding 2 meters. The primary purpose of laser welding is to enhance the strength of the car body connection. Therefore, to ensure weld continuity, traditional clamping cylinders or two-stage flipping units in welding fixtures cannot achieve weld seam clamping in this special lap joint location. Summary of the Invention

[0007] To address at least one of the problems in the background art, the present invention proposes a laser welding mold clamping mechanism and a method for using it.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A laser welding mold clamping mechanism includes an upper plate, a lower plate, an upper mold, and a clamping assembly;

[0010] The upper plate and the lower plate abut against each other, and a weld seam is formed at the abutment.

[0011] Above the seam to be welded, the upper and lower plates form a “C” shaped area;

[0012] The upper mold is located in the "C"-shaped area, with a gap between the upper end and the upper plate, and the lower end pressing against the upper plate;

[0013] Several of the aforementioned clamping assemblies are sequentially abutted against each other along the length of the seam to be welded, installed in the “C”-shaped area, fixedly connected to the upper mold, and one end presses against the upper plate.

[0014] Preferably, the upper mold has an upper contact surface and a side contact surface on the side facing the clamping assembly, and the upper contact surface is perpendicular to the side contact surface.

[0015] Preferably, the inner wall surface of the "C"-shaped region is a limiting surface, which is used to block the upper mold moving upward.

[0016] Preferably, the clamping assembly includes a connecting block, an adjusting shim, a pressure block, a countersunk bolt, a positioning bolt, and a positioning pin;

[0017] The connecting block and the pressure block are connected by countersunk bolts, and at least one of the adjusting shims is located in the connection gap between the connecting block and the pressure block;

[0018] At least two symmetrically arranged positioning bolts are perpendicular to the countersunk bolts and pass through the pressure block to connect with the side contact surface;

[0019] One of the positioning pins is installed between symmetrical positioning bolts, passes through the pressure block, and connects to the side contact surface;

[0020] The connecting block abuts against the upper contact surface, and the pressing block presses down on the upper plate;

[0021] At least one of the adjusting shims is installed between the pressure block and the side contact surface.

[0022] Preferably, the length of the seam to be welded is greater than 2m, and the height of the "C"-shaped area is 57mm to 107mm.

[0023] Preferably, it also includes a base plate, a primary slide module, a secondary slide module, and a lower mold.

[0024] The primary slide module is fixedly mounted on the base plate and is used to push the secondary slide module to move to one side of the "C" shaped area.

[0025] The secondary slide module is installed on the primary slide module and is fixedly connected to the upper mold, and is used to drive the upper mold and clamping assembly to move in the vertical direction, thereby separating from or pressing the upper plate.

[0026] The lower mold is fixedly mounted on the base plate to support the lower plate.

[0027] Preferably, air grooves are provided on the surface of the lower mold that contacts the lower plate;

[0028] The gas tank is equipped with a pipe connector at its end, which is used to introduce inert gas into the gas tank.

[0029] Preferably, the width of the air groove does not exceed 4 mm and the depth does not exceed 10 mm.

[0030] A method of use for the above-mentioned laser welding mold fixture mechanism includes the following steps:

[0031] The upper plate and the lower plate are pressed together;

[0032] Move the upper mold with the clamping assemblies installed to the "C"-shaped area so that each clamping assembly presses down on the upper plate;

[0033] Determine if the gap between the clamping assembly and the upper plate is less than the target value. If not, detach the clamping assembly from the upper plate, adjust the number or thickness of the adjusting shims in the clamping assembly, and press the upper plate back down until the gap between the clamping assembly and the upper plate is less than the target value.

[0034] Preferably, determining whether the gap between the clamping assembly and the lower plate is less than the target value includes the following steps:

[0035] Use a feeler gauge to measure the gap between the fixture assembly and the upper plate;

[0036] If the gap is less than 0.3mm, it is less than the target value; otherwise, it is greater than the target value.

[0037] The beneficial effects of this invention are:

[0038] 1. This invention designs a clamping assembly for the "C"-shaped area, and then installs the clamping assembly in the upper mold. When the upper plate and the lower plate are attached, the upper mold can be controlled to move, so that the clamping assembly filling the "C"-shaped area can press the upper plate at one time. This replaces the segmented clamping method of the clamping cylinder of the traditional welding fixture. The structure is simple and reliable, and the clamping cycle time is greatly reduced.

[0039] 2. Both the upper and lower molds of this invention are CNC machined. The upper mold is a connecting pressure block assembly that abuts against the upper plate; the lower mold is fixed on the base plate and supports the lower plate. The mold's shape perfectly replicates the surface shape of the plate in a narrow space. While ensuring structural strength, it makes great use of the effective space and meets the required safety distance in the design. This provides an effective reference for the design of fixtures and tooling for such narrow spaces and specially shaped plates in the future.

[0040] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 A schematic diagram of the "C"-shaped area of ​​a laser welding mold clamping mechanism according to the present invention is shown;

[0043] Figure 2 A diagram showing the fit between the "C"-shaped region and the fixture assembly of a laser welding mold clamping mechanism according to the present invention is provided.

[0044] Figure 3 A structural diagram of the clamp assembly of the present invention is shown;

[0045] Figure 4 A complete schematic diagram of the weld seam to be welded according to the present invention is shown;

[0046] Figure 5 The diagram shows the installation positions of the upper mold and clamping assembly in the "C"-shaped area;

[0047] Figure 6 A schematic diagram of a laser welding mold clamping mechanism according to the present invention is shown;

[0048] Figure 7 A schematic diagram of the lower mold of the present invention is shown;

[0049] Figure 8 It shows Figure 7 A large view of area A in the middle.

[0050] In the diagram: 1. Upper plate; 101. "C" shaped area; 102. Limiting surface; 103. Welding seam 103; 2. Lower plate; 3. Upper mold; 301. Upper contact surface; 302. Side contact surface; 4. Fixture assembly; 401. Connecting block; 402. Adjusting shim; 403. Pressure block; 404. Countersunk bolt; 405. Positioning bolt; 406. Positioning pin; 5. Base plate; 6. Primary slide module; 7. Secondary slide module; 8. Lower mold; 801. Air groove; 802. Pipe joint. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] A laser welding mold clamping mechanism, such as Figure 1 and Figure 2 As shown, the assembly includes an upper plate 1, a lower plate 2, an upper mold 3, and a clamping assembly 4. The upper plate 1 abuts against the lower plate 2, forming a weld seam 103 at the abutment. Above the weld seam 103, the upper plate 1 and lower plate 2 form a "C"-shaped area 101. The upper mold 3 is located within the "C"-shaped area 101, with a gap between its upper end and the upper plate 1, and its lower end abutting against the lower plate 2. Several clamping assemblies 4 are sequentially abutted against each other along the length of the weld seam 103 and installed within the "C"-shaped area 101. Furthermore, the clamping assembly 4 is fixedly connected to the upper mold 3, with one end pressing against the upper plate 1. The upper mold 3 has an upper contact surface 301 and a side contact surface 302 on the side facing the clamping assembly 4, with the upper contact surface 301 perpendicular to the side contact surface 302. The inner wall of the “C”-shaped region 101 has a limiting surface 102, which faces the “C”-shaped region 101 and is used to block the upper mold 3 from moving upward.

[0053] It should be noted that the space in the "C"-shaped area 101 is very small, with a minimum height of only 54mm and a maximum height of only 107mm; and as Figure 4 As shown, the weld seam 103 in this area is curved, and its total length is greater than 2 meters. With the upper mold 3 pressing against the upper plate 1, the distance between the upper mold 3 and the top of the "C"-shaped area 101 is greater than 10mm, allowing sufficient height for the upper mold 3 to be lifted.

[0054] Furthermore, combined Figure 2 and Figure 3It is known that the clamp assembly 4 includes a connecting block 401, an adjusting shim 402, a pressure block 403, a countersunk bolt 404, a positioning bolt 405, and a positioning pin 406. The connecting block 401 and the pressure block 403 are connected by the countersunk bolt 404, and at least one adjusting shim 402 is located in the connection gap between the connecting block 401 and the pressure block 403; at least two symmetrically arranged positioning bolts 405 are perpendicular to the countersunk bolt 404 and pass through the pressure block 403 to connect with the side contact surface 302; a positioning pin 406 is installed between the symmetrical positioning bolts 405, passes through the pressure block 403, and connects with the side contact surface 302; the connecting block 401 abuts against the upper contact surface 301, and the pressure block 403 presses against the upper plate 1; at least one adjusting shim 402 is installed between the pressure block 403 and the side contact surface 302.

[0055] It should be noted that the clamping assembly 4 is detachably connected to the upper mold 3 via positioning bolts 405 and positioning pins 406. Therefore, the clamping assembly 4 can move together with the upper mold 3. When the upper plate 1 contacts the lower plate 2, the upper mold 3 drives the clamping assembly 4 to press the upper plate 1, making the upper plate 1 and the lower plate 2 completely fit together. Compared with the traditional cylinder clamping structure, this structure can make the weld seam 103 fit more closely, ensuring the final weld quality. The adjusting shim 402 is a comb-shaped shim used for adjustment in both vertical and horizontal directions. The pressure block 403 is provided with holes, which are oblong holes with a center distance of 5mm, which facilitates the pin positioning and bolt fixing after the adjusting shim 402 is added or removed.

[0056] It should be further explained that, since the clamping assembly 4 is detachably connected to the upper mold 3, the clamping assembly 4 can be structurally adjusted. For example, if the gap between the upper plate 1 and the lower plate 2 is large (greater than or equal to 0.3 mm), the number or thickness of the adjusting shims 402 between the connecting block 401 and the pressure block 403 can be increased, so that the upper plate 1 and the lower plate 2 can fit together completely.

[0057] like Figure 5 As shown in the figure, the clamping assembly 4 is symmetrical from left to right. In some embodiments, there are 16 sets on each side, for a total of 32 sets. By manually adjusting the shims 402, the gap of the weld seam 103 to be welded can be clamped and eliminated, which can effectively reduce the negative impact of the weld gap on laser welding.

[0058] Furthermore, such as Figure 6 As shown, the laser welding mold clamping mechanism also includes a base plate 5, a primary slide module 6, a secondary slide module 7, and a lower mold 8. The primary slide module 6 is fixedly mounted on the base plate 5 and is used to push the secondary slide module 7 towards the "C"-shaped area 101. The secondary slide module 7 is mounted on the primary slide module 6 and is fixedly connected to the upper mold 3, used to drive the upper mold 3 and clamping assembly 4 to move vertically, thereby detaching from or pressing against the upper plate 1. The lower mold 8 is fixedly mounted on the base plate 5 and is used to support the lower plate 2.

[0059] It should be noted that the primary slide module 6 includes a cylinder, a slide, a clamping mechanism, and a limiting mechanism (including mechanical hard limits and soft limits). During operation, the cylinder drives the primary slide to move along the X-axis. After reaching the working position, it limits the vertical movement to prevent the slide from tipping over along one side of the guide rail. On the other hand, after reaching the working position, the cylinder closes, mechanically limiting the slide in the horizontal direction (X-axis) to ensure the stability and rigidity of the primary mechanism on the fixture BASE (base plate 5).

[0060] It should be further explained that the secondary slide module 7 consists of a pair of symmetrical four-bar linkages. After the primary slide is in position, the secondary slide is driven by another cylinder to move the connecting rod, causing the clamping assembly 4 to move vertically. When the crank and connecting rod of the linkage mechanism are in the same straight line, the linkage mechanism moves to the "dead point" (the motion characteristic of the crank-rocker four-bar linkage). Due to the irreversible mechanical characteristic of the "dead point", even if a large force is applied to the driven end (the mold clamping end), the dead point state cannot be broken. Therefore, the linkage mechanism can provide a sufficiently large clamping force to the pressure block 403.

[0061] Furthermore, such as Figure 7 and Figure 8 As shown, an air groove 801 is provided on the surface of the lower mold 8 that contacts the lower plate 2. A pipe connector 802 is installed at the end of the air groove 801 for supplying air to the air groove 801. In addition, the width of the air groove 801 does not exceed 4mm and the depth does not exceed 10mm.

[0062] It should be noted that the surface of the lower mold 8 is CNC profiled to ensure that its shape fits perfectly with the lower plate 2, allowing for complete control of the gap between the lap welds of the upper and lower plates during the welding process of the lower plate 2. Simultaneously, the lower mold 8 is a one-piece casting, providing support around the lower plate. A full ring of air grooves 801 is machined on the surface of the lower mold 8. The pipe connector 802 is connected to the lower mold 8 via pipe threads. During welding, inert gas is continuously introduced into the air grooves 801 through the air inlet of the pipe connector 802, expelling air from the grooves. This isolates the back of the weld from air, enabling post-weld discoloration control and rapid cooling of the weld.

[0063] It needs to be further explained that, in combination Figure 2 and Figure 8 As can be seen, the "C"-shaped region 101 in this invention has a unique shape, and the back of the upper mold 3 needs to be designed to mimic the shape, preserving the material thickness and strength of the mold to the greatest extent possible. The lower mold 8 is designed as a frame shape, which has higher structural strength and deformation of less than 0.3mm under large span conditions.

[0064] A method of use for the laser welding mold fixture mechanism described above includes the following steps:

[0065] S1: Place the upper plate 1 against the lower plate 2; S2: Move the upper mold 3, equipped with the clamping assembly 4, into the "C"-shaped area 101, so that each clamping assembly 4 presses down on the upper plate 1; S3: Determine whether the gap between the clamping assembly 4 and the upper plate 1 is less than the target value. If not, the cylinder drives the linkage mechanism to move, and the clamping assembly 4 disengages from the upper plate 1. Adjust the number or thickness of the adjusting shims 402 in the clamping assembly 4, and press down on the upper plate 1 again until the upper plate 1 is pressed tightly, so that the gap between the clamping assembly 4 and the upper plate 1 is less than the target value. Specifically, a feeler gauge can be used to measure the gap between the clamping assembly 4 and the upper plate 1; if the gap is less than 0.3mm, it is less than the target value, and vice versa.

[0066] It should be noted that in the method of this invention, horizontal movement can be achieved through the primary slide module 6, and vertical movement can be achieved through the secondary slide module 7. The upper mold 3 is fixedly connected to both ends of the secondary slide module 7. Therefore, when the secondary slide module 7 is raised or lowered, it can drive the clamping assembly 4 to press down on the upper plate 1 or move away from the upper plate 1. When it is necessary to adjust the clamping assembly 4, the secondary slide module 7 can be driven to lift, and then the clamping assembly 4 can be removed from the upper mold 3, thereby adjusting the thickness of the adjusting shim 402 (such as changing the shim specification and increasing or decreasing the number of shims).

[0067] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A laser welding mold clamping mechanism, characterized in that, It includes an upper plate (1), a lower plate (2), an upper mold (3), and a fixture assembly (4); The upper plate (1) abuts against the lower plate (2), and a weld seam (103) is formed at the abutment. Above the weld seam (103), the upper plate (1) and the lower plate (2) form a "C" shaped area (101). The upper mold (3) is located in the "C" shaped area (101), with a gap between the upper end and the upper plate (1), and the lower end pressing against the upper plate (1). Several of the clamping assemblies (4) are installed in the "C"-shaped area (101) along the length of the weld seam (103), fixedly connected to the upper mold (3), and one end presses against the upper plate (1). The upper mold (3) is provided with an upper contact surface (301) and a side contact surface (302) on the side facing the clamp assembly (4), and the upper contact surface (301) and the side contact surface (302) are perpendicular to each other; The clamp assembly (4) includes a connecting block (401), an adjusting shim (402), a pressure block (403), a countersunk bolt (404), a positioning bolt (405), and a positioning pin (406). The connecting block (401) and the pressure block (403) are connected by countersunk bolts (404), and at least one of the adjusting shims (402) is located in the connection gap between the connecting block (401) and the pressure block (403); At least two symmetrically arranged positioning bolts (405) are perpendicular to the countersunk bolts (404) and pass through the pressure block (403) to connect with the side contact surface (302); One of the positioning pins (406) is installed between symmetrical positioning bolts (405), passes through the pressure block (403) and connects to the side contact surface (302); The connecting block (401) abuts against the upper contact surface (301), and the pressing block (403) presses down on the upper plate (1). At least one of the adjusting shims (402) is installed between the pressure block (403) and the side contact surface (302).

2. The laser welding mold clamping mechanism according to claim 1, characterized in that, The inner wall upper surface of the "C"-shaped area (101) is a limiting surface (102), which is used to block the upper mold (3) moving upward.

3. The laser welding mold clamping mechanism according to claim 1, characterized in that, The length of the weld seam (103) is greater than 2m, and the height of the "C"-shaped area (101) is 57mm to 107mm.

4. A laser welding mold clamping mechanism according to any one of claims 1-3, characterized in that, It also includes a base plate (5), a primary slide module (6), a secondary slide module (7), and a lower mold (8); The primary slide module (6) is fixedly mounted on the base plate (5) and is used to push the secondary slide module (7) to move towards the "C" shaped area (101); The secondary slide module (7) is installed on the primary slide module (6) and is fixedly connected to the upper mold (3). It is used to drive the upper mold (3) and the clamp assembly (4) to move in the vertical direction, thereby separating from or pressing the upper plate (1). The lower mold (8) is fixedly installed on the base plate (5) to support the lower plate (2).

5. The laser welding mold clamping mechanism according to claim 4, characterized in that, Air grooves (801) are provided on the surface of the lower mold (8) that contacts the lower plate (2). The gas tank (801) is equipped with a pipe joint (802) at its end, which is used to pass inert gas into the gas tank (801).

6. The laser welding mold clamping mechanism according to claim 5, characterized in that, The width of the air groove (801) shall not exceed 4 mm and the depth shall not exceed 10 mm.

7. A method of use, characterized in that, The laser welding mold clamping mechanism according to any one of claims 1-6 comprises the following steps: Place the upper plate (1) against the lower plate (2); Move the upper mold (3) with the clamping assembly (4) installed into the "C" shaped area (101) so that each clamping assembly (4) presses down on the upper plate (1). Determine whether the gap between the clamp assembly (4) and the upper plate (1) is less than the target value. If not, detach the clamp assembly (4) from the upper plate (1), adjust the number or thickness of the adjusting shims (402) in the clamp assembly (4), and press the upper plate (1) back down until the gap between the clamp assembly (4) and the upper plate (1) is less than the target value.

8. A method of use according to claim 7, characterized in that, Determining whether the gap between the fixture assembly (4) and the upper plate (1) is less than the target value includes the following steps: Use a feeler gauge to measure the gap between the clamp assembly (4) and the upper plate (1); If the gap is less than 0.3mm, it is less than the target value; otherwise, it is greater than the target value.

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