KR101968652B1 - Undershipping for vehicles with needle punching for improved absorption performance - Google Patents

Abstract

The present invention relates to an under cover for a needle punching coupling vehicle to improve sound absorbing performance and a manufacturing method thereof and, more specifically, relates to an under cover for a needle punching coupling vehicle to improve sound absorbing performance and a manufacturing method thereof, which can improve dust caused by a glass fiber and reduce a weight and production costs. According to the present invention, the under cover comprises a PET outer cover layer, a glass fiber composite sheet, and a PET inner cover layer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an under cover for a needle punching tie-

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an under cover for a needle punching binding vehicle for improving sound absorption performance and a manufacturing method thereof, A fiberglass composite sheet is supplied between the layers to set the depth of the needle punching depth to a high level to thereby reduce the weight of the glass fiber and prevent the glass fiber from being separated from the trimming portion to thereby improve the dust caused by the glass fiber, To an under cover for a punching binding vehicle and a manufacturing method thereof.

Generally, when the vehicle is running, the vehicle body collides with the atmospheric air, thereby receiving a resistance. Such a resistance is called an air resistance, and the air resistance is largely classified into a drag force and a lift force.

Here, the drag force refers to a resistance force that a vehicle body that directly impacts air while traveling in the opposite direction of travel, and a lift phenomenon refers to a phenomenon that a vehicle body floats due to a pressure difference generated in the upper and lower portions of the vehicle during driving.

Therefore, in the early stage of automobile development, the target air resistance coefficient is set in order to reduce the air resistance as much as possible, and the body shape is determined by carrying out a lot of simulations and wind tunnel tests to achieve the target.

On the other hand, after the basic body shape is determined, various means are provided to improve the aerodynamic performance by reducing the drag and the like, one of which is an undercover installed under the engine room of the vehicle.

This undercover prevents undesirable noises such as road noise from being transmitted to the room through the engine room and the dash panel while driving, and improves the durability by preventing the parts of the engine room from being contaminated with external dust, thereby improving aerodynamic performance.

In addition, the floor under cover mounted on the floor of the vehicle is installed at the bottom of the engine, the transmission and the cooling fan to protect the engine and the transmission from the external impact, as well as the noise generated from the engine or transmission And prevents foreign matter from entering the interior of the vehicle from the outside.

However, in the conventional undercover, when the air is introduced at a high speed, the inflow air is not directly discharged to the rear lower portion of the vehicle but is dispersedly discharged to a portion opened at both sides of the front wheel to generate a flow loss, There is a problem that the overall air resistance increases during traveling.

In addition, such air resistance lowers the aerodynamic performance of the vehicle, thereby increasing the cooling drag to increase the air-fuel ratio, and the heat generated in the engine room is not discharged smoothly, Problems also arise.

Conventionally, GMT (Glass Fiber Mat Thermoplastic) was used as the material of the floor undercover. The GMT sheet refers to a composite material of a plate shape comprising a polypropylene (polyethylene) resin and a glass thermosetting reinforcement material. The thermoplastic resin is used as a matrix Matrix " refers to a sheet-shaped intermediate article in which glass fiber pads are reinforced in between.

GMT is a composite material for forming parts that has both light weight of plastic and mechanical properties of reinforcement. It is advantageous to obtain desirable physical properties comparatively cheaply by proper combination of matrix resin and reinforcement. However, GMT material has pore Since it is impossible to manufacture different thicknesses depending on the regions, there is almost no sound-absorbing performance, and it is impossible to realize an integral type full under cover due to the compression and injection molding method, and since the density of the material itself is high There is a problem that the total weight of the vehicle is increased.

BACKGROUND ART [0002] Conventional automotive underbarkers for automobiles generally include a cover body formed by mixing or kneading glass fiber and polypropylene into a sheet form, a laminate made of a flame retardant water repellent nonwoven fabric laminated on the upper surface of the cover body, And is made of a resin injection product.

Since the temperature of the exhaust pipe of the undercover is in the range of about 700 to 800 ° C., the conventional polypropylene resin injection molding can not escape thermal deformation. . However, this is also a factor that hinders the secondary performance of the vehicle such as cost increase and weight increase.

Dust is generated in the glass fiber used for the under cover, dust that is generated when the glass fiber is separated due to the under cover trimming part at the time of work, and there is a problem that flushing or skin troubles are generated due to being seated on the skin of the worker.

Accordingly, it is an object of the present invention to provide an under cover in which no dust due to the use of glass fiber is produced during the manufacture of an under cover, the sound absorption performance is improved, and the cost is reduced by reducing weight.

[Patent Document 1] Patent Publication No. 2013-0107627 (published on Mar. 10, 2013) [Patent Document 2] Patent Registration No. 1819050 (Registered on October 10, 2018) [Patent Literature 3] Patent Registration No. 1821499 (Registered on January 17, 2018) [Patent Document 4] Patent Registration No. 1788134 (Registered on October 13, 2017)

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an undercoat which is made of PET (polyethylene terephthalate), a glass fiber composite sheet and PET, And punching by needle punching followed by molding by hot pressing through press molding and cooling so as to prevent dust and deviations caused by the operation of the glass fiber to prevent dust from being generated.

Another object of the present invention is to provide a fiberglass composite sheet between PET layers to improve the noise, vibration and harshness (NVH) performance of a vehicle, The punching reduces the weight and cost for weight reduction and improves sound absorption performance.

The present invention provides a PET envelope layer, a glass fiber composite sheet, and a PET inner layer layer, wherein the PET envelope layer, the glass fiber composite sheet and the PET inner layer layer are bound together by needle punching so as to be integrated;
Wherein the PET envelope layer and the PET inner layer layer are made of polyethylene terephthalate and comprise 200 to 400 gsm (g / m < 2 >), wherein the glass fiber composite sheet has a glass fiber length of 80 to 100 mm When the needle punching is performed between the PET sheathing layer and the PET endothelium layer, a depth depth at which the glass fibers do not flow outward by the needles is set to be high, and after the hot press is preheated, 1. A vehicle under cover which is formed by molding,
The thickness of the under cover which press-molds the PET envelope layer, the glass fiber composite sheet, and the PET inner layer layer through a hot press in a state in which the PET envelope layer and the PET inner layer layer are integrally formed by needle punching, And a thickness for satisfying the NVH performance is in the range of 2 to 5 mm.

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In the present invention, the under cover is made of PET (polyethylene terephthalate), a glass fiber composite sheet and PET, and is punched to be integrally connected by needle punching, and then pre-heated and cold An effect of providing an under cover which prevents dust and deviation due to the operation of the glass fiber to prevent dust from occurring and improves work performance and strengthens the strength through bonding of the glass fiber composite sheet and PET to improve rigidity It is.

In order to improve the NVH performance of noise, vibration, and harshness of a vehicle, a glass fiber composite sheet is supplied between PET layers to reduce weight and cost for lightening by needle punching, The film is not inserted, thereby improving the high frequency NVH performance and providing the effect of improving the sound absorption performance.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a front view showing a state in which a raw fabric of an under cover is separated,
Fig. 2 is a cross-sectional view of a state in which the under cover fabric of the present invention is combined and needle-
Fig. 3 is an enlarged view of the main part in a state in which the under cover fabric of the present invention is engaged
Fig. 4 is a plan view showing a state in which the under cover fabric of the present invention is molded
5 is a schematic view showing a molding process for the undercover hot press of the present invention
6 is a block diagram showing an under cover molding process of the present invention
FIG. 7 is a graph showing the state of the surface detail state of the material of the present invention magnified 400 times
Fig. 8 is a graph showing the state of the surface detail state of the material of the present invention magnified 400 times

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a cross-sectional view of a state in which the under cover fabric of the present invention is combined with needle punching, FIG. 3 is a cross-sectional view of the under cover of the present invention, Fig. 4 is a plan view of a molded state using the under cover fabric of the present invention. Fig.

In order to improve the NVH performance of noise, vibration and harshness of the vehicle, a glass fiber composite sheet is supplied between the PET layers to reduce weight and cost for lightening by needle punching, To improve the high frequency NVH (noise) performance, and to provide an effect of improving sound absorption performance.

The under cover 10 of the present invention mainly comprises a PET envelope layer 20, a glass fiber composite sheet 30 and a PET inner layer 40. The PET envelope layer 20, the glass fiber composite sheet 30, and the PET And the endothelial layers 40 are bound together by a needle punching 50 so as to be integrated.

The PET envelope layer 20 and the PET endothelial layer 40 are made of polyethylene terephthalate and provide a yarn thickness of 4 to 6 denier and are made of 200 to 400 gsm (g / m 2) It is preferable to form it so as to have a thickness.

If the PET skin layer 20 and the PET endothelial layer 40 are 200 gsm or less, there is a disadvantage that the NVH performance is largely lowered and the bonding strength is lowered.

When the PET sheath layer 20 and the PET endothelial layer 40 are 400 gsm or more, there is a disadvantage that the NVH performance is not greatly improved and a bonding strength is not improved. Therefore, it is preferably 300 gsm.

When the thickness of the PET skin layer 20 and the thickness of the PET endothelial layer 40 is less than 1 mm, there is a disadvantage in that the NVH performance is largely lowered and the bonding strength is lowered.

If the PET sheath layer 20 and the PET inner layer 40 are 5 mm or more, there is a disadvantage that the NVH performance is not greatly improved and a bonding strength is not improved. Therefore, the thickness is preferably 3 mm.

The glass fiber composite sheet 30 of the present invention has a yarn thickness of 6 to 20 탆 and is made of long fibers of 80 to 100 mm in length of glass fibers to form the PET outer layer 20 and the PET inner layer 40 When the needle punching 50 is carried out between the needle and the needle, the depth of the glass fiber does not flow outward by the needles.

When the length of the glass fiber is 80 mm or less, the fiber is separated toward the outside by the needle as the fiber is closer to the short fiber,

When the length of the glass fiber is 100 mm or more, it is supplied to the long fiber so that it is difficult to provide the same weight as that of holding the uniform thickness, and the bonding force is lowered.

The glass fiber composite sheet 30 is preferably formed to have a thickness of from 6 to 12 mm, and has a thickness of from 500 to 1,000 gsm.

If the glass fiber composite sheet 30 has a thickness of 500 gsm or less, there is a disadvantage that the NVH performance is largely lowered and the bonding force is lowered.

When the glass fiber composite sheet 30 is 1,000 gsm or more, there is a disadvantage that the NVH performance is not greatly improved and a bonding strength is not improved. Therefore, it is preferably 750 gsm.

When the glass fiber composite sheet 30 has a thickness of 6 mm or less, there is a disadvantage in that the NVH performance is largely lowered and the bonding strength is lowered.

When the glass fiber composite sheet 30 is 12 mm or more, there is a disadvantage that the NVH performance is not greatly improved and a bonding strength is not improved. Therefore, the thickness of the glass fiber composite sheet 30 is preferably 9 mm, By keeping the depth to a minimum for a long fiber length, the glass fiber is prevented from flowing out.

5 is a schematic view showing a molding process for the undercover hot press of the present invention. The PET envelope layer 20, the glass fiber composite sheet 30 and the PET endothelial layer 40 are integrally formed by a needle punching 50 And then cold-formed by the under cover 10.

The under cover 10 is formed by preheating the hot press 60 at a temperature of 180 to 220 캜 for 70 to 80 seconds to form a PET envelope layer 20 and a glass fiber composite sheet 30, And the PET endothelial layer 40 are supplied to the preheated hot press 60 and cold-formed to a temperature of 15 to 20 占 폚 for 90 to 110 seconds.

When the temperature of the hot press 60 is 180 占 폚 or lower, there is a disadvantage in that the bonding force is lowered and the rigidity such as tensile strength is lowered. On the other hand, when the temperature is higher than 220 占 폚, Is heated and cooled to 200 deg.

When the cold forming time of the hot press 60 is 90 seconds or less, there is a disadvantage in that the bonding force is lowered and the rigidity such as tensile strength is lowered. When the hot press 60 is 110 seconds or more, So that cold forming is preferably performed for 100 seconds.

After the preheating using the hot press 60, the cold press molding is performed to maintain the mold temperature of the hot press 60 at 15 to 20 DEG C and maintain the molding time of 90 to 110 seconds, thereby forming the under cover 10 To complete.

The bonding strength between the PET outer cover layer 20 and the glass fiber composite sheet 30 and the PET inner layer 40 is weakened when the mold temperature of the hot press 60 is maintained at a molding time of 18 ° C or less and 90 seconds or less When the mold temperature of the hot press 60 is maintained at 20 ° C or more and for a molding time of 110 seconds or more, the bonding strength between the PET outer cover layer 20 and the glass fiber composite sheet 30 and the PET inner layer 40 becomes strong But it is difficult to maintain the appearance quality. Therefore, the mold temperature of the hot press 60 is preferably molded at 20 DEG C for 100 seconds.

The PET envelope layer 20 and the glass fiber composite sheet 30 and the PET inner layer 40 are integrally joined together through a needle punching 50 to prevent fold separation and prevent peeling, It is possible to improve the NVH performance by improving deflection phenomena caused by the PET endothelium layer 20 and the PET endothelial layer 40.

The under cover 10 (10) is press molded through a hot press 60 in a state in which the PET sheath layer 20, the glass fiber composite sheet 30 and the PET inner layer 40 are integrally formed by a needle punching 50 ) Is formed such that the rim portion and the portion requiring the stiffness on the mounting seat surface are 1.0 to 3.0 mm in thickness and the thickness to satisfy the NVH performance is 2 to 5 mm.

Figs. 7 and 8 relate to a detailed surface state photograph of the material of the present invention magnified 400 times, wherein glass fiber has a long elongated structure, and PET and PP fiber have been found to provide a structure in which a yarn is warped You can see the phenomenon that the LM fiber is melted by heat, not the glass fiber.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

end. (S10)

A PET envelope layer 20 made of polyethylene terephthalate and a PET inner layer 40 are provided so as to have a thickness of 3 mm and a thickness of 300 gms respectively by providing a yarn thickness of 4 to 6 denier and the PET envelope layer 20 and the PET inner layer layer 40 to provide a glass fiber composite sheet 30 having a thickness of 9 mm and having a thickness of 500 gsm.

I. The needle punching binding step (S20)

The PET envelope layer 20, the glass fiber composite sheet 30, and the PET endothelial layer 40 are bundled so as to be integrated with each other through the needle punching 50.

All. Hot press preheating step (S30)

Preheating is performed for 70 to 80 seconds so that the temperature of the hot press 60 is maintained at 180 to 220 deg.

la. In the cold forming step (S40)

After preheating by using the hot press 60, cold press molding is performed, and molding of the under cover 10 is completed by maintaining the mold temperature of the cold mold at 15 to 20 DEG C and maintaining the cold time of 90 to 110 seconds .

hemp. Trim step (S50)

And then the cold-injected under cover 10 is trimmed.

In order to improve NVH performance, the present invention provides a fiberglass composite sheet between a PET sheathing layer and an endothelium layer to provide light weight and prevent glass fiber separation from the trimming portion by needle punching, thereby improving dust caused by glass fiber and reducing weight and cost And to improve the sound absorption performance.

10: undercover 20: PET sheath layer
30: Our fiber composite sheet 40: PET inner layer layer
50: Needle punching

Claims (7)

The PET envelope layer 20 and the glass fiber composite sheet 30 and the PET endothelial layer 40 are made of a PET pouch layer 20, a glass fiber composite sheet 30 and a PET endothelial layer 40. The PET envelope layer 20, To be integral with each other;
The PET envelope layer 20 and the PET inner layer layer 40 are made of polyethylene terephthalate and have a thickness of 200 to 400 gsm (g / m 2). The glass fiber composite sheet 30 is made of glass fiber When the needle punching 50 is performed between the PET skin layer 20 and the PET endothelial layer 40 by using long fibers having a length of 80 to 100 mm, the depth of depth at which the glass fibers do not flow outward by the needles In which the under cover 10 is formed by cold forming by heating after preheating the hot press 60,
The under cover 10 (10) is press molded through a hot press 60 in a state in which the PET sheath layer 20, the glass fiber composite sheet 30 and the PET inner layer 40 are integrally formed by a needle punching 50 ) Is formed to have a thickness of 1.0 to 3.0 mm in a portion requiring the rigidity of the rim portion and the mounting seat surface, and a thickness of 2 to 5 mm in order to satisfy the NVH performance. Punching undercarriage for needle punching. delete delete delete delete delete delete

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