Lightweight engine bay cover and method of manufacturing the same

Abstract

The application provides a light-weight engine compartment cover and a preparation method thereof, comprising a cover inner plate and a cover outer plate, wherein during preparation, the cover inner plate and the cover outer plate are integrally formed by injection molding; the cover inner plate and the cover outer plate are riveted and positioned by using plastic hinge pressing sheets and clamping blocks; the cover inner plate and the cover outer plate are welded into a cover assembly by using needle welding; the outer side of the cover assembly is painted; an adjustable nut is installed on a mounting bracket on the cover inner plate; and the mounting bracket is installed on an engine front end frame by using bolts. The cover inner plate and the cover outer plate are formed by using plastic material injection molding, and are welded into a cover assembly, and the outer plate of the cover assembly is painted, so that the functional requirements of appearance, detachability, safety and reliability, and durable use are met.

Description

Technical Field

[0001] This invention belongs to the field of automotive technology, and in particular relates to a lightweight engine compartment cover and its preparation method. Background Technology

[0002] Currently, traditional automotive engine hoods are made of stamped metal inner and outer panels, welded and painted, and then connected to the vehicle body via metal hinges. The overall production, assembly, and maintenance technologies are mature. However, with the rise of electric vehicles, due to the high energy consumption of electric vehicle batteries, lightweighting is essential. Therefore, vehicle lightweighting is a trend in vehicle body development, and the inherent weight of traditional metal hoods becomes apparent. Replacing metal hoods with plastic hoods can reduce overall weight by approximately 50%, a very significant effect. Furthermore, plastic hoods offer equal or slightly better performance than metal hoods in various aspects, such as stiffness modes, surface strength, and reaction deformation. Their corrosion resistance is also far superior to sheet metal products. Therefore, developing a lightweight engine hood is imperative. Summary of the Invention

[0003] To address the problems existing in the background art, the first objective of this invention is to provide a lightweight engine compartment cover, the technical solution of which is as follows:

[0004] A lightweight engine compartment cover includes an inner cover panel and an outer cover panel, both made of plastic and integrally molded by injection molding. Multiple plastic hinge plates are integrally molded at the upper and lower edges of the inner side of the outer cover panel, and each plastic hinge plate has a rivet hole. A rivet insertion groove is injection molded on the inner side of the inner cover panel to accommodate the folded plastic hinge plates. An inner plate rivet hole is provided in the rivet insertion groove, and rivets are used to sequentially pass through the inner plate rivet hole and the rivet hole to fasten the inner cover panel and the outer cover panel together. A retaining block is also injection molded in the rivet insertion groove to press against one edge of the plastic hinge plate.

[0005] A mounting bracket is injection molded on the outer side of the inner panel of the cover. The mounting bracket has a threaded hole for screwing in an adjustable nut. The adjustable nut includes a stud and a hexagonal flange head. The stud has a through hollow post. The hexagonal flange head is fixed to the upper outer side of the stud. The hollow post of the stud is used to adjust the gap between the inner panel of the cover and the front frame of the engine by adjusting the screwing length of the adjustable nut through the bolts that fix the front frame assembly of the engine.

[0006] A second objective of this invention is to provide a method for manufacturing a lightweight engine compartment cover, comprising the following steps:

[0007] Step 1: Prepare the inner and outer panels of the cover by injection molding.

[0008] Step 2: Use the plastic hinge pressure plate on the outer panel of the cover and the locking block on the inner panel of the cover to rivet and position the inner panel and the outer panel of the cover.

[0009] Step 3: Use needle welding to weld the inner side of the inner panel of the cover and the inner side of the outer panel of the cover together to form the cover assembly;

[0010] Step 4: Spray paint the outer surface of the cover assembly;

[0011] Step 5: Install the adjustable nut onto the mounting bracket on the inner plate of the cover;

[0012] Step 6: Install the mounting bracket onto the front frame of the engine using bolts;

[0013] Step 7: Install other accessories.

[0014] As a preferred embodiment of the present invention, in step one, the inner and outer panels of the cover are made of PP+EPDM+TD30, the outer panel has a wall thickness of 3.2mm, and the inner panel has a wall thickness of 2.5mm.

[0015] As a preferred embodiment of the present invention, in step three, the inner and outer panels of the cover are welded with 42 needle-punched welding points to ensure welding strength. The needle-punched welding points are designed with two redundancies: firstly, there are reserved welding points among the 42 needle-punched welding points, which can be canceled or added according to the strength requirements of the assembly product; secondly, the 42 needle-punched welding points are designed as double-row needle welding, reserving space for three and four rows of welding heads to increase the welding strength of a single point.

[0016] As a preferred embodiment of the present invention, in step four, the process of painting the outer panel of the cover assembly adopts the same process and equipment as that of ordinary exterior bumpers.

[0017] As a preferred embodiment of the present invention, a discontinuous spot welding method is used during needle welding. To avoid noise generated by vibration, sound-absorbing felt can be glued to the outer plate of the cover.

[0018] The beneficial effects of this invention are as follows:

[0019] (1) This invention uses plastic material to injection mold two main parts, the inner panel and the outer panel of the cover, and then welds them to form the cover assembly. The outer panel of the cover assembly is painted. The product has a higher degree of freedom in shape. More complex shapes, such as small R-angle structures, cannot be achieved by sheet metal, but can be achieved through the design of plastic hair cover. It meets the functional requirements of use: detachable, safe and reliable, durable and other functions. The performance of plastic hair cover is equal to or slightly better than that of metal hair cover, such as stiffness mode, surface strength, reaction force deformation; the corrosion resistance is much higher than that of sheet metal products.

[0020] (2) Compared to traditional metal covers, there are differences in mold tooling and production equipment. The plastic cover process provided in this application requires injection molds and injection molding via an injection molding machine. The cover assembly requires welding fixtures, and the painting process does not require electrophoretic rust prevention treatment; it only requires the same spraying process as the exterior bumper, making the manufacturing process simple. Compared to the metal cover process (stamping-welding, painting, and final assembly), there are fundamental differences in equipment investment. Overall, the investment in plastic covers is less than that in metal covers. In addition, plastic covers can meet the requirements of lightweight vehicle bodies, reducing costs by an average of 20%-30% compared to sheet metal, catering to the future automotive market.

[0021] (3) Considering the potential for inaccurate positioning during welding, a pressure plate insertion groove and a pressure block are injection molded on the inner and outer panels of the cover simultaneously. A plastic hinge pressure plate is injection molded on the outer panel. The plastic hinge pressure plate is folded into the pressure plate insertion groove, positioned using the pressure block, and then riveted to secure its position, ensuring no positional deviation during welding. Furthermore, the one-piece injection molding process saves on hinges and mounting parts compared to metal cover products, reducing costs.

[0022] (4) The cover assembly of this application uses a non-standard adjustable nut to mate with the threaded hole on the mounting bracket of the injection-molded inner plate of the cover to form the assembly structure. By rotating the hexagonal flange head of the adjustable nut, zero contact between the bolt and the surface of the matching part (fixing the front frame of the engine) is achieved, thereby realizing the X-axis adjustable function of the assembly product, and thus making it easier to achieve product appearance matching. Superior gap surface difference matching: Due to different manufacturing processes, the product tolerance of the plastic cover injection molding process is more superior than that of sheet metal stamping and springback tolerance control. Attached Figure Description

[0023] Other objects and results of the invention will become more apparent and readily understood with reference to the following description taken in conjunction with the accompanying drawings. In the drawings:

[0024] Figure 1 This is a schematic diagram of the cover assembly structure in this invention.

[0025] Figure 2 for Figure 1 Another perspective diagram.

[0026] Figure 3 for Figure 1 Another perspective diagram.

[0027] Figure 4 This is a schematic diagram of the structure of the outer cover plate in this invention.

[0028] Figure 5This is a schematic diagram of the structure of the inner panel of the cover in this invention.

[0029] Figure 6 for Figure 2 BB section view.

[0030] Figure 7 for Figure 3 Enlarged view of point A in the middle.

[0031] Figure 8 for Figure 7 CC section view during assembly.

[0032] Figure 9 for Figure 7 DD section view during assembly.

[0033] Figure 10 for Figure 7 EE section view during assembly.

[0034] Figure 11 This is a schematic diagram of the adjustable nut in this invention.

[0035] The attached figures are labeled as follows: inner cover plate 1, outer cover plate 2, plastic hinge pressure plate 21, pressure plate riveting hole 211, pressure plate insertion groove 11, inner plate riveting hole 111, rivet 3, clip 112, mounting bracket 12, threaded hole 121, adjustable nut 4, stud 41, hexagonal flange head 42, hollow column 411, bolt 5, engine front frame 6. Detailed Implementation

[0036] To enable those skilled in the art to better understand the technical solutions and advantages of the present invention, the present application will be described in detail below with reference to the accompanying drawings, but this is not intended to limit the scope of protection of the present invention.

[0037] In the description of this application, it should be noted that the terms "inner," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0038] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; or they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0039] Example 1

[0040] See Figure 1-11 As shown: A lightweight engine compartment cover includes an inner cover panel 1 and an outer cover panel 2. Both the inner cover panel 1 and the outer cover panel 2 are made of plastic and are integrally molded by injection molding. Multiple plastic hinge plates 21 are integrally formed on the upper and lower edges of the inner side of the outer cover panel 2. The plastic hinge plates 21 are provided with plate riveting holes 211. A plate insertion groove 11 is injection molded on the inner side of the inner cover panel 1. The plate insertion groove 11 is used to accommodate the folded plastic hinge plates 21. The plate insertion groove 11 is provided with inner plate riveting holes 111. The inner cover panel 1 and the outer cover panel 2 are fastened together by rivets 3 sequentially through the inner plate riveting holes 111 and the plate riveting holes 211. A retaining block 112 is also injection molded in the plate insertion groove 11. The retaining block 112 is used to press a certain edge of the plastic hinge plate 21.

[0041] A mounting bracket 12 is injection molded on the outer side of the inner plate 1 of the cover. The mounting bracket 12 has a threaded hole 121 for screwing in an adjustable nut 4. The adjustable nut 4 includes a stud 41 and a hexagonal flange head 42. The stud 41 has a through hollow post 411. The hexagonal flange head 42 is fixed to the upper outer side of the stud 41. The hollow post 411 of the stud 41 is used to adjust the gap between the inner plate 1 of the cover and the front frame 6 of the engine by means of the bolts 5 that fix the front frame 6 of the engine, and by means of the screwing length of the adjustable nut 4.

[0042] Example 2

[0043] A method for manufacturing a lightweight engine compartment cover includes the following steps:

[0044] Step 1: Prepare the inner cover panel 1 and outer cover panel 2 by injection molding. The materials of the inner cover panel 1 and outer cover panel 2 are PP+EPDM+TD30. The outer cover panel 2 has a wall thickness of 3.2mm, which can achieve good appearance performance. The inner cover panel 1 has a wall thickness of 2.5mm, which can achieve the best weight reduction target while also playing a reinforcing role.

[0045] Step 2: Use the plastic hinge plate 21 on the outer cover 2 and the locking block 112 on the inner cover 1 to rivet and position the inner cover 1 and the outer cover 2. Specifically, the inner side of the inner cover 1 is attached to the inner side of the outer cover 2, the plastic hinge plate 21 on the outer cover 2 is folded over and placed into the groove 11 on the inner cover 1, the locking block 112 is used to fix the position of the plastic hinge plate 21, and the rivet 3 is used to rivet the plastic hinge plate 21 to the inner cover 1 to achieve the positioning and fastening effect.

[0046] Step 3: The inner side of the inner panel 1 and the inner side of the outer panel 2 of the cover are welded together by needle welding to form the cover assembly. The inner panel 1 and the outer panel 2 of the cover are welded together by 42 needle welding points to ensure the welding strength. The needle welding points are designed with two redundancies: first, there are reserved welding points among the 42 needle welding points, which can be canceled or added according to the strength requirements of the assembly product; second, the 42 needle welding points are designed as double-row needle welding, with reserved space for three and four rows of welding heads to increase the single-point welding strength. During needle welding, a non-continuous point welding method is used. To avoid noise generated by vibration, sound-absorbing felt can be glued to the outer panel of the cover.

[0047] Step 4: Paint the outer surface of the cover assembly; the painting process for the outer panel of the cover assembly can use the same process and equipment as ordinary exterior bumpers.

[0048] Step 5: Install the adjustable nut 4 on the mounting bracket 12 on the inner plate 1 of the cover; specifically: turn the hexagonal flange head 42 and screw the stud 41 into the threaded hole 121 of the mounting bracket 12;

[0049] Step 6: Install the mounting bracket 12 onto the engine front frame 6 using bolts 5; specifically: insert bolts 5 into the hollow post 411 of stud 41 and then screw them onto the engine front frame 6.

[0050] Step 7: Install other accessories.

[0051] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A lightweight engine compartment cover, comprising an inner cover panel and an outer cover panel, characterized in that: Both the inner and outer panels of the cover are made of plastic and are integrally molded by injection molding. Multiple plastic hinge plates are integrally molded at the upper and lower edges of the inner side of the outer panel, and the plastic hinge plates are provided with rivet holes. A rivet insertion groove is injection molded on the inner side of the inner panel, which is used to accommodate the folded plastic hinge plates. The rivet insertion groove is provided with inner panel rivet holes. The inner panel and outer panel are fastened together by rivets passing through the inner panel rivet holes and the rivet holes in sequence. A retaining block is also injection molded in the rivet insertion groove, which is used to press one edge of the plastic hinge plate. A mounting bracket is injection molded on the outer side of the inner panel of the cover. The mounting bracket has a threaded hole for screwing in an adjustable nut. The adjustable nut includes a stud and a hexagonal flange head. The stud has a through hollow post. The hexagonal flange head is fixed to the upper outer side of the stud. The hollow post of the stud is used to adjust the gap between the inner panel of the cover and the front frame of the engine by adjusting the screwing length of the adjustable nut through the bolts that fix the front frame assembly of the engine.

2. The method for preparing a lightweight engine compartment cover according to claim 1, characterized in that, Includes the following steps: Step 1: Prepare the inner and outer panels of the cover by injection molding. Step 2: Use the plastic hinge pressure plate on the outer panel of the cover and the locking block on the inner panel of the cover to rivet and position the inner panel and the outer panel of the cover. Step 3: Use needle welding to weld the inner side of the inner panel of the cover and the inner side of the outer panel of the cover together to form the cover assembly; Step 4: Spray paint the outer surface of the cover assembly; Step 5: Install the adjustable nut onto the mounting bracket on the inner plate of the cover; Step 6: Install the mounting bracket onto the front frame of the engine using bolts; Step 7: Install other accessories.

3. The method for preparing a lightweight engine compartment cover according to claim 2, characterized in that: In step one, the inner and outer panels of the cover are made of PP+EPDM+TD30, with the outer panel having a wall thickness of 3.2mm and the inner panel having a wall thickness of 2.5mm.

4. The method for preparing a lightweight engine compartment cover according to claim 2, characterized in that: In step three, the inner and outer panels of the cover are welded with 42 needle-punched welding points to ensure welding strength. The needle-punched welding points are designed with two redundancies: first, there are reserved welding points among the 42 needle-punched welding points, which can be canceled or added according to the strength requirements of the assembly product; second, the 42 needle-punched welding points are designed as double-row needle welding, with reserved space for three and four rows of welding heads to increase the welding strength of a single point.

5. The method for preparing a lightweight engine compartment cover according to claim 2, characterized in that: In step four, the painting process for the outer panel of the cover assembly uses the same process and equipment as that for ordinary exterior bumpers.

6. The method for preparing a lightweight engine compartment cover according to claim 2, characterized in that: When needle welding, a discontinuous spot welding method is used. To avoid noise generated by vibration, sound-absorbing felt can be glued to the outer plate of the cover.

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