CN210760239U - Fuel storage box inner wall butt fusion structure - Google Patents

Abstract

The utility model relates to an inner wall welding structure of a fuel storage tank. The welding structure comprises a built-in component body and a welding surface structure arranged on the built-in component body. The welding surface structure is configured as a welding surface flange and/or a welding surface convex Since then, the welding surface protrusion is set to a cylindrical pit structure, the diameter of the pit is less than φ2.5mm, and the ratio of height to diameter is less than 1.2; this technical solution greatly improves the welding surface structure of the built-in parts by changing the structure. The welding quality of the built-in parts and the storage box body improves the production efficiency, reduces the production cost, and is conducive to energy saving and environmental protection.

Description

An inner wall welding structure of a fuel storage tank

technical field

The invention relates to a welding structure for the inner wall of a fuel storage tank, in particular to a welding structure and a welding method for the inner wall of a fuel storage tank, and belongs to the technical field of automobile structural parts.

Background technique

Compared with metal fuel tanks, fuel storage tanks are more and more widely used in the industry because of their advantages of light weight, high safety, good corrosion resistance, and full use of vehicle space. In the traditional fuel storage tank industry, the body blow molding After forming, the welding parts, such as valves, exhaust joints, etc., are welded to the storage box body by first punching holes. With the development of technology, there are also new requirements for fuel tanks, such as low emission, low noise, and high pressure resistance. Traditional fuel tanks can no longer meet these new technical requirements.

The new fuel tank arranges the welding parts inside the fuel tank, and the blow molding and welding are carried out simultaneously. The welding parts welded to the inner wall of the fuel tank are called built-in parts, including pipe clamps, columns, oil separators, wave boards, etc., built-in welding parts The poor quality of welding with the body may easily lead to deformation or even rupture of the fuel tank during use. Those skilled in the art have been trying new solutions to solve this technical problem, but the solutions have been unsatisfactory.

SUMMARY OF THE INVENTION

The present invention is aimed at the problems existing in the prior art, and provides a welding structure for the inner wall of the fuel storage tank. The technical solution greatly improves the welding quality of the built-in component and the fuel storage tank body by changing the welding surface structure of the built-in component.

In order to achieve the above purpose, the technical solution of the present invention is as follows, a fuel storage tank inner wall welding structure, the welding structure includes a built-in part body and a welding surface structure arranged on the built-in part body, and the welding surface structure is set as a welding surface Raised flanges and/or weld faces.

优选为1.5mm—2.0mm，其中，高度和直径的比例小于1.2，优选高度和直径的比例为1.0—1.2。首先上述范围的麻点结构不需要将麻点单独加热就可以满足产品焊接的要求，并且达到内置件拔脱力的要求，上述方案是申请人经过大量的理论分析和长时间的实践不断创新总结得到。在麻点与料胚熔接的过程中，熔融态的料胚最先将热量传递至麻点与料胚平行的表面，使麻点表面形成初始熔融层，初始熔融层内的分子运动能量和自由体积较大，高分子链可以进行整链的扩撒运动，在轴向压力的作用下，麻点表面的部分高分子链会逐渐从自己所在的熔融层扩散至料胚的熔融层，并与料胚的高分子发生缠结，两个熔融层界面的高分子链不断扩散、缠结、形成熔接面，(因为料胚的温度是一直下降的，所以希望实际生产过程的初始熔融层能够迅速形成)热量继续通过熔接面传至麻点根部。如果麻点直径过大，一方面一些内置件的拔脱力要求较高，需要在法兰面上布置几十个、甚至几百个麻点，麻点平面度不容易满足，另一方面，麻点直径大，形成初始熔融层耗时长，熔接慢，熔接质量不够，可能还会形成假焊(因为初始熔融层形成慢，麻点与料胚并未实际熔接上)。As an improvement of the present invention, the welding surface protrusion is configured as a cylindrical pit structure, and the diameter of the pit is smaller than

It is preferably 1.5mm-2.0mm, wherein the ratio of height to diameter is less than 1.2, preferably the ratio of height to diameter is 1.0-1.2. First of all, the pitting structure in the above range can meet the requirements of product welding without heating the pitting alone, and can meet the requirements of the pull-out force of the built-in parts. . In the process of welding the pits and the blank, the molten blank first transfers heat to the surface parallel to the pits and the blank, so that the surface of the pits forms an initial molten layer, and the molecular motion energy and free The volume is large, and the polymer chain can carry out the spreading movement of the whole chain. Under the action of axial pressure, part of the polymer chain on the surface of the pit will gradually diffuse from the molten layer where it is to the molten layer of the blank, and interact with it. The macromolecule of the blank is entangled, and the polymer chains at the interface of the two molten layers continue to diffuse, entangle, and form a fusion surface. Forming) heat continues to be transferred to the root of the pit through the welding surface. If the diameter of the pits is too large, on the one hand, the pull-out force of some built-in parts is high, and dozens or even hundreds of pits need to be arranged on the flange surface, and the flatness of the pits is not easy to meet. If the spot diameter is large, it takes a long time to form the initial molten layer, the welding is slow, the welding quality is not enough, and false welding may also be formed (because the initial molten layer is formed slowly, the pits and the blank are not actually welded).

If the ratio of height to diameter is too large, it means that the pitting is high, and the barrier layer of the blank is destroyed during the process of inserting the blank. The actual experiment was done with pits with a diameter of 2.5mm. Under the same production rhythm, the pull-out force of the built-in parts was not as good as that of the pits with a diameter of 2.0. It is because of the large diameter of the pits, some of the pits and the blank are falsely welded, but not really welded. If the diameter of the pits is small, on the one hand, the requirements for injection molding are high, on the other hand, the number of pits is required to be high, and the flange area of the built-in part is required to be relatively large, and the layout of the entire fuel storage system will also be more difficult.

As an improvement of the present invention, the thickness d of the pockmarked welding area formed by the welding surface structure and the blank is not greater than 1 mm, which meets the requirements of welding quality, but the thickness of the welding area is too high, requiring more energy and time to complete, reducing production efficiency, waste of resources.

As an improvement of the present invention, the welding face flange is set to one of a rectangle, a square, a circle, and an ellipse.

As an improvement of the present invention, the flange of the welding surface is provided with an overflow groove.

A method for welding the inner wall of a fuel storage tank for welding a structure, the method comprises the following steps: the material of the welding surface of the built-in part is the same as that of the blank; The main function of the built-in welding surface of the cylindrical pitted part and the overflow groove is to exhaust gas during the welding process. During the welding process, place the built-in on the tooling, move it to the designated position, and then insert the cylindrical pit on the welding surface of the built-in directly into the blank, where the pit is the cylindrical convex structure on the welding surface of the built-in. Before the pits come into contact with the blank, the surface of the pits fails to form a melting zone. After the contact with the blank, because the temperature of the blank is much higher than the melting temperature of the material, the surface of the pits melts. Under the action of pressure, the melting zone is formed by The unstable flow becomes a stable flow. At this time, the hydraulic cylinder pushes the mold to act on the blank with the same pressure as the pockmark acts on the blank. The boundary of the melting zone of the blank advances toward the blank. With the increase of heating time, The melting area of the pits is getting bigger and bigger. Under the action of pressure, the melting area formed by the pitting into a mushroom shape is in full contact with the blank, forming a barb structure, and there may be a gap between the flange and the blank.

As an improvement of the present invention, in the pitted melting zone formed in step 3), the minimum distance b from the top of the pitted melting zone to the inner wall of the fuel tank is not less than 1 mm; the minimum distance c from the top of the pitted melting zone to the EVOH layer is not less than 0.2mm; the thickness d of the pitted melting zone is not more than 1mm. Some built-in parts, such as uprights, also make separate requirements for the wall thickness l of the storage box body where the built-in parts are welded, requiring l not less than 5mm. For a larger welding surface, an exhaust overflow groove is provided on the welding surface, and an exhaust overflow groove is designed between every two or three rows of pits.

A storage box production and processing method, the method comprises the following steps:

1) Two blank blanks;

2) Pre-forming of blanks;

3) The welding of the built-in parts is realized through the welding structure of the inner wall;

4) Secondary mold clamping and blow molding;

5) The blow molding is completed, and the fuel storage tank is formed.

In described step 3), the material of the welding surface of the blank and the built-in part is the same;

In the step 3), in order to improve the welding strength of the built-in part and the blank, the welding surface should be fully contacted with the blank,

As shown in Figure 5, the welding surface of the built-in part with cylindrical pits can be used. For larger welding surfaces, the exhaust overflow groove should be added when designing the flange, and the design between every two or three rows of pits should be used. Exhaust overflow trough, several exhaust holes on each exhaust overflow trough or in the middle of the welding surface flange. The main function of the overflow groove is to exhaust gas during the welding process.

In the step 3), during the welding process, the built-in part is placed on the tooling, moved to a designated position, and then the cylindrical pit on the welding surface of the built-in part is directly inserted into the blank, wherein the pit is the welding surface of the built-in part. The cylindrical convex structure, before the pits are in contact with the blank, the surface of the pits fails to form a melting zone. After contacting the blanks, because the temperature of the blanks is much higher than the melting temperature of the material, the surface of the pits melts, and the surface of the pits melts under pressure. Under the action, the melting area changes from unstable flow to stable flow. At this time, the hydraulic cylinder pushes the mold to act on the blank with the same pressure as that of the pitting on the blank, and the boundary of the melting zone of the blank advances to the blank. With the increase of heating time, the melting area of pitting becomes larger and larger. Under the action of pressure, the melting area formed by pitting into mushroom shape is in full contact with the blank, forming a barb-mounted structure, and there may be gaps between the flange and the blank. void.

In the pitted melting zone formed in step 3), the minimum distance b from the top of the pitted melting zone to the inner wall of the fuel tank is not less than 1 mm; the minimum distance c from the top of the pitted melting zone to the EVOH layer is not less than 0.2 mm; the thickness of the pitted melting zone is not less than 0.2 mm. d is not more than 1mm. Some built-in parts, such as uprights, also make separate requirements for the wall thickness l of the storage box body where the built-in parts are welded, requiring l not less than 5mm.

优选为1.5mm—2.0mm，其中，高度和直径的比例小于1.2，优选高度和直径的比例为1.0—1.2，可以利用料胚的温度将麻点熔化后与料胚熔接，实现了能源的充分利用；Compared with the prior art, the present invention has the following advantages: 1) the diameter of the pits in the technical solution is smaller than

It is preferably 1.5mm-2.0mm, wherein the ratio of height to diameter is less than 1.2, and the ratio of height to diameter is preferably 1.0-1.2. The temperature of the blank can be used to melt the pits and then fuse them with the blank to achieve sufficient energy. use;

2) In terms of production efficiency, because the process of heating the built-in parts is reduced, the heating time of each fuel tank is not less than 20s, which greatly improves the production efficiency;

3) In terms of welding quality, the applicant has undergone a large number of experiments and carried out many theoretical and experimental analyses. The above dimensions are the optimal size, and the welding quality meets the requirements of product use. On multiple built-in parts such as uprights, the product meets the requirements of relevant standards and can meet the needs of customers;

4) In terms of energy consumption and process, there is no need for another heat source to heat the built-in parts, which simplifies the production process and saves tooling investment and reduces energy consumption;

5) In terms of environmental pollution, the built-in welding technology significantly reduces the HC emission of the fuel tank, which is beneficial to environmental protection.

Description of drawings

Figure 1 is a schematic diagram of the structure of the fuel tank;

2 is a schematic diagram of a fuel tank body with a six-layer structure;

3 is a schematic diagram of a fuel tank body with a seven-layer structure;

4 is a schematic diagram of the entire production process of the fuel tank of the present invention;

Figure 5 is a schematic view of the structure of the built-in part;

Fig. 6 is the structural representation of pitting melting zone;

Figure 7 is a schematic diagram of a hollow cylindrical pit structure;

Figures 8 and 9 are schematic diagrams of structures of different welding surfaces.

In the picture: 100, storage box body, 101, valve, 102, oil separator, 103, column, 104, wave-proof board, 105, buckle, 1, outer layer of new material, 2, outer layer of return material, 3. Outer bonding layer, 4. Inner barrier layer, 5. Inner bonding layer, 6. Inner new material layer, 7. Inner recycle layer, 8. Material blank, 9. Built-in parts, 10. Cylindrical Pockmarks, 11. Welding surface flange, 12. Pockmark melting zone, 13. Hollow cylindrical pits, 14. Overflow groove.

Detailed ways:

In order to deepen the understanding of the present invention, the present embodiment will be described in detail below with reference to the accompanying drawings.

Embodiment 1: Referring to FIG. 5 , a welding structure for the inner wall of a fuel storage tank, the welding structure includes a built-in body and a welding surface structure arranged on the built-in body, and the welding surface structure is provided as a welding surface flange 11 and a welding surface structure. / or welding surface protrusions; the welding surface protrusions are configured as cylindrical pit structures 10, the diameter of the pits is 1.5mm-2.0mm, wherein the ratio of height to diameter is 1.0-1.2. The thickness d of the pitted welding area is not greater than 1 mm; the welding surface flange is set to one of a rectangle, a square, a circle, and an ellipse, and the welding surface flange is provided with an overflow groove 14 .

In practical applications, choose according to different needs, see Figure 8-Figure 9,

Fig. 8 is an embodiment, the higher requirements for the welding strength of the built-in parts means that the number of pits is also larger, and the overflow groove 14 has a good exhaust effect, which can also make the entire welding surface and the blank better welded .

Figure 9 is another embodiment. When the degree of freedom of the surrounding space of the built-in part is not high, a rectangular welding surface flange can also be selected. The pitting no longer presents a ring structure like a circular welding surface, but is neatly arranged , The deeper overflow groove ensures smooth exhaust.

The above-mentioned welding surface structures have been tested and tested, and the welding quality meets the performance requirements.

Example 2: Referring to Figures 5 to 7, a method for welding the inner wall of a fuel storage tank for welding the structure, the method includes the following steps: first, the material of the welding surface of the built-in part and the blank should be selected as the same material as possible. For the welding strength of the embryo, to make the welding surface fully contact with the blank, the welding surface of the built-in part with cylindrical pits can be used as shown in Figure 5. According to the needs, for larger welding surface, when designing flange 11 The exhaust overflow groove 14 can be added, and the exhaust overflow groove 14 is designed between every two or three rows of pits. The main function of the overflow groove is to exhaust gas during the welding process. During the welding process, place the built-in part on the tooling, move it to the designated position, and then insert the cylindrical pit 10 on the welding surface of the built-in part directly into the blank, wherein the pit 10 is a cylindrical protrusion on the welding surface of the built-in part. Structure, the surface of the pit 10 fails to form a melting zone before contacting with the blank. After contacting with the blank, since the temperature of the blank is much higher than the melting temperature of the material, the surface of the pit melts. Under the action of pressure, the surface of the pit melts. The melting area changes from unstable flow to stable flow. At this time, the hydraulic cylinder pushes the mold to act on the blank with the same pressure as the pockmarks act on the blank. The boundary of the melting zone 12 of the blank advances toward the blank. With the increase of time, the pockmarked melting area 12 becomes larger and larger. Under the action of pressure, the pockmarked mushroom-shaped melting area is in full contact with the blank to form a barb-mounted structure. As shown in Figure 6, the flange 11 may There are gaps between the blanks.

The welding surface of the built-in part can also be designed as shown in Figure 7. 13 is a hollow circular pit. After welding, the hollow cylindrical pit and the blank will form a melting zone with a ring-mounted mushroom structure. The welding contact surface is larger, and the welding strength of the built-in part and the blank is higher.

In order to prevent the pockmarks from contacting with the inner adhesive layer after welding, resulting in damage to the barrier layer, the diameter d as shown in Figure 5 should be considered between 1.5mm and 2.0mm when designing the size of the pockmarks. After a series of theoretical analysis and experimental analysis, the ratio of pit height h to diameter d is 1.0-1.2, and the pit distance a is not less than d to meet the requirements of use.

One of the key technical indicators to measure the welding strength is the minimum pull-out force of a single pit

The unit of d is mm;

The pull-out force of a single pit measured in the actual test shall not be less than f _min , and the number of pits can be determined according to the type of built-in parts and the pull-out force requirements of specific built-in parts.

Another key technical indicator is the size requirement of the melting zone, as shown in Figure 6,

The minimum distance b from the top of the pitted melting zone to the inner wall of the fuel tank is not less than 1mm;

The minimum distance c from the top of the pitted melting zone to the EVOH layer is not less than 0.2mm;

The thickness d of the pitted melting zone is not more than 1mm.

Embodiment 3: Referring to FIGS. 1 to 4 , a method for producing and processing a fuel storage tank, the method includes the following steps:

1) Two blank blanks;

2) Pre-forming of blanks;

3) The welding of the built-in parts is realized through the welding structure of the inner wall;

4) Secondary mold clamping and blow molding;

5) The blow molding is completed, and the fuel storage tank is formed.

In described step 3), the material of the welding surface of the blank and the built-in part is the same;

In the step 3), in order to improve the welding strength of the built-in part and the blank, the welding surface should be fully contacted with the blank,

As shown in Fig. 5, the welding surface of the built-in parts with cylindrical pits can be used. According to actual needs, for larger welding surfaces, the exhaust overflow groove 14 can be added when designing the flange 11, every two rows or three. The exhaust overflow groove 14 is designed between the pitting points. The main function of the overflow groove is to exhaust gas during the welding process.

In the step 3), during the welding process, the built-in part is placed on the tooling, moved to a designated position, and then the cylindrical pit 10 on the welding surface of the built-in part is directly inserted into the blank, wherein the pit 10 is the built-in part. The cylindrical convex structure of the welding surface, the surface of the pit 10 fails to form a melting zone before contacting with the blank, and the surface of the pit melts after contacting with the blank because the temperature of the blank is much higher than the melting temperature of the material , Under the action of pressure, the melting area changes from unstable flow to stable flow. At this time, the hydraulic cylinder pushes the mold to act on the blank with the same pressure as that of the pits on the blank. The boundary of the melting zone 12 of the blank As the blank advances, as the heating time increases, the melting area 12 of the pits becomes larger and larger. Under the action of pressure, the melting area formed by the pitting into a mushroom shape is fully contacted with the blank to form a barb structure, as shown in Figure 6 , there may be a gap between the flange 11 and the blank.

The welding surface of the built-in part can also be designed as shown in Figure 7. 13 is a hollow circular pit. After welding, the hollow cylindrical pit and the blank will form a melting zone with a ring-mounted mushroom structure. The welding contact surface is larger, and the welding strength of the built-in part and the blank is higher.

In order to prevent the pitting from contacting with the inner bonding layer after welding, resulting in damage to the barrier layer, when designing the size of the pitting, the diameter d as shown in Figure 5 should be considered between 1.5mm and 2.0mm. After a series of theoretical analysis The ratio of the height and diameter of the pits to the test analysis is 1.0-1.2, and the distance a of the pits is not less than d, which can meet the requirements of use.

One of the key technical indicators to measure the welding strength is the minimum pull-out force of a single pit

The unit of d is mm;

The pull-out force of a single pit measured in the actual test shall not be less than f _min . In addition, the number of pits can be determined according to the type of built-in parts and the pull-out force requirements of specific products.

Another key technical indicator is the size requirement of the melting zone, as shown in Figure 6,

The minimum distance b from the top of the pitted melting zone to the inner wall of the fuel tank is not less than 1mm;

The minimum distance c from the top of the pitted melting zone to the EVOH layer is not less than 0.2mm;

The thickness d of the pitted melting zone is not more than 1mm.

Some built-in parts, such as uprights, also make separate requirements for the wall thickness l of the storage box body where the built-in parts are welded, requiring l not less than 5mm.

Working principle: In the production process of the fuel storage tank or the fuel tank, in order to weld one or more built-in parts with the inner wall of the fuel storage tank, it is generally realized by a two-piece blow molding process, that is, the blank is cut into two pieces. After the blank is pre-formed, the built-in parts are welded to the blank, and finally blow-molded.

Referring to FIG. 1 , the structure of the formed storage tank is as follows. As shown in FIG. 1 , the valve 101 includes but is not limited to a liquid level control valve, a flip valve, and a gravity valve. The storage tank body 100 may include more than one valve 101 , an oil-liquid separator 102 The purpose is to reduce the amount of fuel leakage. In actual products, the oil separator 102 may be directly welded with the storage box body 100 through the welding surface, or it may be installed with the installation clip and welded with the storage box body 100 by the clip. With a built-in oil separator, the main purpose of the upright column 103 is to improve the pressure resistance of the storage tank body 100 . The purpose of the wave shield 104 is to reduce the noise of the fuel tank during the use of the whole vehicle, and the purpose of the buckle 105 is to be installed with pipelines or other accessories. Among them, the anti-wave board 104 and the buckle 105 may be arranged on the upper surface of the storage box body. These similar structures are generally called the built-in parts of the fuel tank structure. At present, the storage box body uses a single-layer or multi-layer structure, and the multi-layer structure has two forms. Six-layer structure and seven-layer structure. A schematic diagram of the six-layer structure of the storage box body is shown in FIG. 2 . In addition to the HDPE raw material, the outer layer of new material layer 1 also needs to add color masterbatch to improve the aging resistance and ultraviolet resistance of the fuel tank. In order to reduce the scrap rate of materials and reduce the cost of use, the source of the outer material return layer 2 is the scrapped fuel tank and flash. The purpose of the barrier layer 4 is to reduce the HC emission during the use of the fuel tank, and EVOH material is usually used. Agent layers 3 and 5, the inner wall of the fuel tank uses a new HDPE material, usually a natural color without the addition of color masterbatch. In addition, there is a seven-layer storage box body structure, as shown in Figure 3, an inner layer return layer 7 is added between the inner layer new material layer 6 and the inner layer adhesive layer 5, which increases the distance from the fuel to the barrier layer. , so as to improve the fuel barrier performance of the storage tank body, and also improve the utilization rate of the return material.

In the process of welding the built-in parts, the material of the welding surface of the blank and the built-in part is the same, and the two can reach the same suitable temperature to obtain sufficient welding strength. In the actual process, the blank is hot, and the built-in part is at room temperature. The welding surface of the built-in parts needs additional heating, and additional energy is required to maintain the temperature of the blank, which not only increases energy consumption, but also reduces production efficiency. Therefore, it is required that the welding surface of the built-in part can be quickly melted during the normal placement process, and then welded with the blank.

During the welding process, there is no chemical connection between the polymer chains, and the welding strength depends on the degree of interpenetration and coiling of the polymer chains between the welding surfaces. The degree of polymer chain diffusion and coiling is mainly affected by factors such as welding pressure, heating temperature, action time and polymer flow characteristics.

In order to improve the welding strength of the built-in part and the blank, to make the welding surface fully contact with the blank, the cylindrical pitted welding surface of the built-in part as shown in Figure 5 can be used. When designing flange 11, an exhaust overflow groove 14 can be added. An exhaust overflow groove is designed between every two or three rows of pits, and there are several exhausts on each exhaust overflow groove or in the middle of the welding surface flange. The main function of the hole and the flash groove is to exhaust gas during the welding process.

It should be noted that the above-mentioned embodiments are not intended to limit the protection scope of the present invention, and equivalent transformations or substitutions made on the basis of the above-mentioned technical solutions all fall into the protection scope of the present invention.

Claims (4)

1. The utility model provides a fuel storage box inner wall welded structure with built-in, built-in and fuel storage box body inner wall welded, its characterized in that, the welded structure of built-in and storage box body is welding face flange and/or welding face arch, the welding face arch sets up to cylindrical pit structure, the diameter of pit is less than phi 2.5mm, and the proportion of height and diameter is less than 1.2.

2. The fuel storage tank inner wall fusion-bonding structure according to claim 1, wherein a thickness d of a pockmark fusion-bonding area formed by the fusion-bonding surface structure and the preform is not more than 1 mm.

3. The fuel storage tank inner wall fusion-bonding structure according to claim 2, wherein the fusion-bonding face flange is provided in one of a rectangular shape, a square shape, a circular shape, and an oval shape.

4. The fuel storage tank inner wall fusion-bonding structure according to claim 3, wherein a flash groove is provided on the fusion-bonding face flange.

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