JP4909207B2 - Body undercover and method for manufacturing body undercover - Google Patents

Description

  The present invention relates to a vehicle body undercover that is formed in a shape that connects a front lower portion, a rear lower portion, or a lateral lower portion of a vehicle body and a lower surface of the vehicle body, forms a shape of the lower portion of the vehicle, and regulates the flow of air during traveling.

  2. Description of the Related Art Conventionally, an under cover for a vehicle body that is disposed under a floor at a front lower part or a rear lower part of a vehicle is known. In many cases, the under cover for the vehicle body is attached to reduce the intrusion of the traveling sound of the vehicle into the room or to prevent the engine noise or the noise such as intake and exhaust from leaking outside the vehicle. In addition, this undercarriage for the vehicle body prevents damage to equipment arranged under the floor of the vehicle body such as piping, auxiliary equipment, fuel tanks, etc. due to splashed stone or sand, etc., and dust or muddy water is formed on the upper part Preventing entry into the engine compartment.

  In addition, by forming the underside of the underbody for the vehicle body in a flat plate shape, the turbulence of the air flowing under the floor of the vehicle is reduced to reduce the air resistance, and the lift acting on the vehicle is reduced to reduce the driving performance at high speeds. There is also the purpose of improving

  2. Description of the Related Art Conventionally, there is a demand among some consumers to form a lower part of a front bumper or a rear bumper of a vehicle so as to extend further to the vicinity of the ground. There is also a demand to attach an under cover having a smooth flat surface on the lower surface of the front part of the vehicle, or to attach a diffuser for efficiently discharging air existing at the lower part of the vehicle toward the rear of the vehicle on the lower surface of the rear part of the vehicle.

  Originally, this type of vehicle has been designed to improve turning performance, left and right turn response, decrease posture change during acceleration / deceleration, increase maximum speed, etc. for competition vehicles that run only on closed paved roads. In order to do so, it is based on making the vehicle low. And in order to maintain the steering stability at the time of high-speed driving | running | working, it is necessary to reduce the lift which acts on a vehicle body. The air that flows from the lower front of the vehicle to the underside of the vehicle decelerates on the lower surface of the vehicle, so that lift acts on the vehicle, but in order to reduce this lift, the air that hits the front of the vehicle is laterally or A front spoiler and a front side wing are formed on the vehicle. In addition, a rear spoiler is formed above the rear part of the vehicle for reducing the downward flow generated at the rear of the vehicle when traveling at high speed.

  Such an appearance that mimics the atmosphere of a racing vehicle is popular among some customers. Especially in recent years, the front bumper is also used for passenger cars, 1.5 BOX cars, and four-wheel drive cars that have a high vehicle height. An under cover that also serves as a front spoiler is provided. A side spoiler that matches the shape of the front spoiler and a rear undercover are also provided. Further, a front under cover in which a current plate is formed on the front lower surface of the vehicle and a diffuser in which a current plate is formed on the rear lower surface of the vehicle are also provided.

  Of these various undercovers and side spoilers, the ones exposed on the side surfaces of the vehicle are low and thin, and conventionally integrally molded products such as urethane resin, polypropylene and FRP are used.

  For example, Japanese Patent Laid-Open No. 2004-203158 (Patent Document 1) discloses a structure behind the bumper lower face decoration portion at the front of the vehicle, which aims to maintain high strength while suppressing an increase in weight. Has been.

  According to the structure at the back of the bumper lower face decoration portion described in Patent Document 1, a reinforcing member in which a large number of reinforcing ribs are formed is disposed at a position close to the inside of the bumper lower face. And both are fastened by the fastening part of the lower end of a bumper lower face decoration part, and also it fastens to the connection board in the vicinity. The connecting plate is fastened to a cross member disposed behind the bumper face. By adopting such a structure, the reinforcing member can be supported on the rear vehicle structure with high strength while suppressing an increase in weight.

  Further, for the purpose of sound insulation and air resistance reduction, an undercover for a vehicle body made of a blow molded product having a light weight and sufficient rigidity is disclosed in Japanese Patent Laid-Open No. 2000-128027 (Patent Document 2).

  The under cover for a vehicle body described in Patent Document 2 is formed by integrally molding a decorative surface attached along a bumper and an under floor portion that closes a floor under an engine compartment of a vehicle. Therefore, the under floor portion has a flat lower surface portion, an upper surface portion covering the lower surface portion, and a flat hollow portion surrounded by the lower surface portion and the upper surface portion. Further, the decorative surface forms a lip spoiler in the lower part of the bumper.

According to the under cover for vehicle bodies described in Patent Document 2, sound insulation, reduction of air resistance, reduction of lift, improvement of air permeability of the engine compartment, prevention of entry of dust, muddy water, etc., prevention of engine damage due to obstacles, etc. It becomes possible to provide functions and the like, and the under cover for the vehicle body can be manufactured at a light weight and at a low price.
JP 2004-203158 A JP 2000-128027 A

  Conventionally, in order to produce an atmosphere resembling a competition vehicle on a general vehicle, optional parts that extend the lower part of the front bumper or rear bumper of the vehicle toward the ground are commercially available. Conventionally, the extension height of the lower part of the bumper is about 5 cm, but in recent years, there is a demand for an optional part of the type that extends downward by 10 cm or more. Furthermore, it is preferable that an under cover for expecting a rectifying effect under the floor is formed on a part that extends the lower part of the front bumper or the rear bumper downward. Furthermore, since these optional parts emphasize the decorative function on the appearance rather than the original aerodynamic performance, the beauty of the surface, the hue, and the texture are particularly important.

  However, if an under cover having a high extension height below the bumper is produced with the structure described in Patent Document 1, problems such as insufficient rigidity and reduced strength occur. When the rigidity of the front spoiler, side spoiler, under cover, etc. is low, the flexure is caused by vibration during traveling, noise and low-frequency vibration are generated, and the vehicle texture is deteriorated.

  If the thickness of the material is increased or ribs are formed in order to improve rigidity and strength, the weight will increase significantly. In addition, when ribs are added to the back surface, sink marks occur after molding on the surface of the portion where the ribs are present, resulting in problems such as poor appearance finish. In particular, the decorative surface that appears on the surface of the vehicle needs to form a texture and aesthetics that match the vehicle price. Therefore, in the past, since it was difficult to take a closed structure as the structure of the under cover, the rigidity and strength required for the under cover tended to be insufficient.

  Moreover, in the undercover for vehicle bodies described in Patent Document 2, a decorative surface that forms part of the outer lower peripheral surface of the vehicle body is also formed by blow molding. This decorative surface, like the outer panel of the vehicle, requires a decorative finish and accuracy that match the price of the vehicle.Blow molding involves controlling the temperature of the resin during molding and setting the cooling time immediately after molding. It is difficult and is not suitable for parts that require precision over a wide range. In particular, when blow molding is applied to front spoilers and side spoilers where the height of the decorative surface exposed on the side of the vehicle is high, distortion of the decorative surface is conspicuous and the shape integrity with the bumper existing at the top is Prone to problems such as damage.

Further, at the time of blow molding, the burnt resin adheres to the edge of the die that discharges the parison that is a molten resin cylinder, and fine streaks (called die lines) may enter the side surface of the parison along the discharge direction. Such streaks usually do not disappear when the parison is blown up. The pressurized air used for blow molding has a pressure of about 8 kgf / cm ² , so that it does not have to be pressed strongly against the mold surface but remains as a streak on the surface of the molded product.

  Also, at the time of blow molding, a resin crimped part is formed when sandwiching a cylindrical molten resin with a mold, but it is difficult to arrange this crimped part in a place where it is not exposed to the outside, etc. There are many molding restrictions. In addition, if an undercover for a vehicle body with a high decorative surface height is formed only by a blow molded product, there is a possibility that the strength when contacting a curb or the like, or the strength of a small stone that collides during high-speed traveling may be insufficient.

FIG. 11 shows a cross-sectional view when the height of the decorative portion is designed to be high while using the structure of the undercover for a vehicle body described in Patent Document 2, and problems occurring at that time will be considered.
As shown in FIG. 11, when the front under cover 110 having a shape in which the height H of the decorative surface 120 is increased using the structure described in Patent Document 2, the lower part of the front bumper 106 and the front under cover are formed. The fastening position LF1 by the fastening screw 80 and the clip 82 for fastening to 110 becomes long, and there arises a problem that it enters the back side of the vehicle body.

  This is because when the gap 116 is formed between the lower surface portion 132 forming the front under cover 110 and the upper surface portion 134, both the lower surface portion 132 and the upper surface portion 134 are sandwiched in order to improve the attachment strength to the front bumper 106. This is because the fastening screw 80 needs to be fastened to the front bumper 106 in order to press-fit the lower surface portion 132 to the upper surface portion 134, and it is necessary to form a punching taper 123 that is greatly raised in a convex shape. . As shown in FIG. 11, when the fastening position LF1 becomes longer from the front edge portion, the attachment rigidity of the front under cover 110 to the front bumper 106 is likely to be reduced. Further, due to wind pressure and vibration during traveling, there are problems such as a gap between the bumper contact portion 127 at the upper end of the front under cover 110 and the front bumper 106, or the front under cover 110 resonating.

  In addition, since the opening H for forming the taper taper 123 is increased by increasing the height H of the decorative surface 120, the airflow AF of the air flowing on the lower surface of the vehicle is disturbed, and the air resistance of the vehicle is increased. This causes a problem that the lift force applied to the motor increases.

  Further, when the front under cover 110 is integrally formed by blow molding using a resin, as shown in FIG. 11, the resin crimping portion WL is easily visible on the front lower end of the front under cover 110. Will be exposed to. Therefore, it is necessary to finish the surface of the crimping portion WL by trimming after blow molding, which causes a problem that the cost of the front under cover 110 increases. In addition, by performing trim processing on the crimping portion WL, the length of the crimping portion WL is shortened or the thickness is thinned. Therefore, the rigidity and strength of the crimping portion WL may be insufficient. If the rigidity and strength of the lower part of the front under cover 110 are reduced, there is a high possibility that a crack will occur in the crimping part WL when a pebble collides during traveling or when it interferes with a curbstone.

  Also, if a part of the front under cover 110 is damaged, the entire front under cover 110 formed by blow molding must be replaced regardless of the extent of the damage range, increasing the burden of repair costs. End up.

  Therefore, the present invention forms a front spoiler and side spoiler with a high height of the decorative portion exposed on the side of the vehicle, and in the under cover that forms a part of the lower surface of the vehicle, it is highly rigid, high in strength, lightweight, and repair costs are low. The purpose is to provide an inexpensive underbody cover.

  In order to achieve the above-described object, the main structure of the undercover for a vehicle body according to the present invention includes a decorative portion that forms a part of the outer lower peripheral surface of the vehicle body and an underfloor portion that forms a part of the lower surface of the vehicle body. The under floor portion is integrally formed between a lower surface portion, an upper surface portion disposed above the lower surface portion with a gap between the lower surface portion, and an outer peripheral edge of the lower surface portion and the upper surface portion. And the decoration portion is fixed to the lower surface portion and the upper surface portion so as to cover the connection portion of the under floor portion.

  As a preferred embodiment of the vehicle body undercover, a pressure-bonding portion that protrudes outwardly between the outer peripheral edges is formed in the connecting portion, and the space between the inner surface on the under floor portion side of the decorative portion and the pressure-bonding portion is formed. Preferably, a continuous concave portion that extends continuously in parallel with the lower surface of the vehicle body is formed on the inner surface of the decorative portion on the under floor portion side, and the crimp portion and the continuous concave portion in the under floor portion are formed. It is preferable to arrange them facing each other. Moreover, it is preferable that the said decoration part fixes directly in the form which pinches | interposes the said lower surface part and the said upper surface part.

  Furthermore, the under cover for the vehicle body is fastened to a lower part of a bumper that covers from a lower front end or lower rear end of the vehicle body to a lower side part of the vehicle body that extends to the wheel arch. The upper end portion on the bumper side is provided with a guide hook having a concave cross section that is folded back from the inner side surface of the decorative portion to the upper end portion on the bumper side and further to the under floor portion side substantially parallel to the inner side surface of the decorative portion. It is preferable to form a guide convex portion having a convex cross section for fitting into the guide hook at the upper end portion on the wheel arch side of the under floor portion and on the bumper side. Moreover, it is preferable to form a bumper contact portion that contacts the bumper lower portion and positions the bumper at the upper end portion on the bumper side of the decoration portion. Furthermore, it is preferable to form a rectifying plate for adjusting the airflow flowing on the lower surface of the vehicle body on the lower surface portion.

  Further, as a manufacturing method of the under cover for a vehicle body, the step of molding the decorative portion by injection molding using a resin material and the upper surface portion and the lower surface portion of the under floor portion are integrated by blow molding using a resin material. Preferably, the method includes a step of forming, and a step of fixing the decorative portion and the under floor portion using rivets.

  According to the present invention, since the decorative portion is fixed so as to cover the connecting portion between the lower surface portion and the upper surface portion, the under cover for the vehicle body has a double structure of the decorative portion and the under floor portion, and the rigidity of the decorative portion is increased. And strength is improved. Therefore, it can withstand the wind pressure during high-speed traveling and can prevent deformation and vibration. Further, even when pebbles or the like collide, it is possible to prevent the decoration part from being damaged by suppressing the deformation of the decoration part.

  Further, even when the decorative portion comes into contact with a curbstone or the like, it comes into contact with the underfloor portion existing behind the decorative portion, so that the deformation of the decorative portion can be suppressed and damage can be prevented. Moreover, since the decoration part covers and hides the connecting part that fixes the lower surface part and the upper surface part, it is possible to prevent the pebbles from directly colliding with the connecting part or contacting the curbstone. It is possible to prevent breakage of the connecting portion which tends to be weak in strength. Moreover, since the space | gap is formed between the lower surface part and upper surface part of an under floor part, it can be made lightweight while being highly rigid. Moreover, since the decoration part is being fixed to the under floor part, high rigidity and intensity | strength are unnecessary for the decoration part itself. Therefore, the decorative portion can be formed thin, and there is no need to provide a reinforcing portion such as a rib. Thereby, a decorative surface can be finished beautifully and smoothly, and it can be made lightweight.

  In addition, by fixing the decorative part to the lower surface part and the upper surface part of the under floor part, the under cover for the vehicle body is attached to the vehicle body and the bumper so that the under floor part and the decorative part are sandwiched together in the part close to the decorative surface. It becomes possible. Therefore, it is possible to maintain the integrity of the appearance at the connection portion between the vehicle body and the decorative portion. Moreover, since the connection part of an under floor part is covered with a decoration part, the external appearance at the time of attaching to a vehicle body can be finished beautifully.

  In addition, since the under floor portion and the decorative portion are separate parts, it is only necessary to perform a decorative finishing process only on the decorative portion, so that variations in set colors can be increased without deteriorating productivity. Even if the decorative part is painted, only one part of the undercover for the car body needs to be painted, so compared to handling the entire under cover for the car body, the product handling in the painting process is reduced. It becomes easy. Further, it is possible to replace only the decorative part that is easily damaged, thereby improving maintainability and reducing the cost of repair.

  In addition, by forming a crimping part that protrudes outward as a connecting part and placing the crimping part and the inner surface of the decorative part in close proximity, the decorative part deforms inward due to wind pressure or impact during travel. Even in this case, since the inner side of the decorative portion contacts the crimping portion of the under floor portion, further deformation of the decorative portion can be suppressed, and generation or breakage of vibration can be prevented.

  Furthermore, on the inner surface of the under floor part side in the decorative part, a continuous concave part extending continuously in parallel with the lower surface of the vehicle body is formed, and the crimping part and the continuous concave part in the under floor part are arranged facing each other. When the decorative portion is deformed inward, the continuous concave portion and the crimping portion can be easily engaged to prevent excessive deformation of the decorative portion.

Furthermore, the underbody cover for the vehicle body is fastened to the lower part of the bumper at the front end lower part or the rear end lower part of the vehicle body, and is formed in the decorative part at the wheel arch side in the decorative part and at the upper end part on the bumper side. Since the guide hook has a structure in which the guide convex portion formed in the under floor portion is fitted, the wheel arch side of the decorative portion is opened and a gap is prevented from being generated between the bumper and the decorative portion. In particular, the decorative portion that is relatively thin and directly receives the wind pressure during high-speed traveling is greatly deformed, and the wheel arch side of the decorative portion has a structure that is difficult to be directly fastened to the bumper. Therefore, this configuration is effective. . In addition, when fixing the decorative portion and the under floor portion, the guide protrusion of the under floor portion is used as an impact to insert the guide hook of the decorative portion, thereby positioning the under floor portion and the decorative portion in the width direction. It can be carried out.
Further, by adopting a structure in which the upper end portion on the bumper side of the decorative portion is brought into contact with the lower portion of the bumper, the decorative portion and the bumper can be positioned to prevent the occurrence of a gap.

  In addition, by forming a smooth rectifying plate with reduced irregularities on the lower surface portion of the under floor portion, it is possible to maintain the flow velocity of the air flowing on the lower surface of the vehicle and to reduce the lift and effectiveness acting on the vehicle body. Further, by forming fins that regulate the direction of air flow, the air flow can be prevented from being disturbed, and the flow velocity of the air flowing on the lower surface of the vehicle can be maintained.

  In addition, by using an injection-molded product made of a resin material for the decorative part of the undercover for the vehicle body, it is possible to finish with a high dimensional accuracy even for products with a large area, and to finish the appearance beautifully. be able to. Moreover, the shape which has closed space can be easily shape | molded by integrally forming the under floor part of the undercover for vehicle bodies by blow molding. Therefore, it is possible to form an underfloor portion that is relatively thin and lightweight, yet has high sound insulation and high rigidity and strength.

  Furthermore, the decorative part formed by injection molding covers the connecting part of the under floor part formed by blow molding, and is fixed to the lower surface part and the upper surface part by rivets, so that the vicinity of the decorative part of the under cover is double-structured It is possible to improve the rigidity and strength of the decorative part and to withstand the wind pressure during high-speed traveling. In addition, by covering the pressure bonding part of the resin formed at the time of blow molding with a decorative part, even if the front lower part of the vehicle is brought into contact with the curb or when the bounced pebbles collide, Since force is applied only through the portion, it is possible to prevent damage to the crimped portion that is relatively weak against impact.

Hereinafter, a typical embodiment of a vehicle body undercover according to the present invention will be specifically described with reference to the drawings.
FIG. 1 is an external perspective view of a box-type passenger car to which a vehicle body under cover according to the present invention is attached. FIG. 2 is an exploded perspective view when the vehicle body under cover according to the present invention is applied to a front under cover. . FIG. 3 is an enlarged perspective view of the front under cover shown in FIG. 2 observed from another direction. 4 is an IV arrow view of the front lower wheel arch portion 22 shown in FIG. 2, and is a perspective view showing a state after the decorative portion 20 is fitted and fixed to the under floor portion 30. 5 is a cross-sectional view taken along line VV shown in FIG.

  As shown in FIG. 1, four wheels 5 are generally attached to a vehicle body 4 of a passenger car. A front bumper 6 is attached to the front end of the vehicle body 4 so as to form a portion from the lower front end of the vehicle body 4 to the front wheel arch, and the rear wheel arch from the lower rear end of the vehicle body 4 to the rear end of the vehicle body 4. A rear bumper 8 is attached to form a part extending up to.

  Further, in the vehicle 2 shown in FIG. 1, a front under cover 10 is fastened to the lower part of the front bumper 6 of the vehicle body 4, and a rear under cover 60 is fastened to the lower part of the rear bumper 8. And the side spoiler 70 of the shape which can take harmony with the front under cover 10 and the rear under cover 60 is fastened by the side surface lower part of the vehicle body 4. As shown in FIG.

  From the front surface to the side surface of the front under cover 10, a step shape 12 simulating a front side spoiler is formed. Although not shown in FIG. 1, a current plate that regulates the airflow flowing through the lower surface of the vehicle body 4 is formed on the under floor portion formed on the inner lower surfaces of the front under cover 10 and the rear under cover 60.

Next, the structure of the front under cover 10 which is one form of the vehicle body under cover will be described with reference to FIGS.
As shown in FIGS. 2 to 5, the front under cover 10 includes a decorative portion 20 that forms the outer lower peripheral surface of the front bumper 6 and an under floor portion 30 that forms a part of the lower surface of the vehicle body.

  The under floor portion 30 includes a lower surface portion 32 that forms the lower surface of the vehicle body 4 and an upper surface portion 34 that faces the lower part of the engine room of the vehicle 2. The lower surface portion 32 and the upper surface portion 34 are fixed to each other at the connecting portion 11 formed on the outer periphery of the under floor portion 30. Furthermore, between the lower surface part 32 and the upper surface part 34, as shown in FIGS.

  A front lower wheel arch portion 22 that forms a lower portion on the front side of the wheel arch for the front wheel in the vehicle 2 is provided at both left and right ends of the decorative portion 20. As shown in FIGS. 4 and 5, the bumper side upper end portion of the front lower wheel arch portion 22 has an underside substantially parallel to the inner side surface of the decorative portion 20 from the inner surface of the decorative portion 20 to the upper end portion on the bumper side. A guide hook 24 having a concave cross-sectional shape that is folded back to the floor portion 30 side is formed. A guide convex portion 44 having a convex cross section is formed at the bumper side upper end portion of the wheel arch portion of one under floor portion 30. In the embodiment shown in FIG. 5, the under floor portion 30 is formed by welding the lower surface portion 32 and the upper surface portion 34 with the crimping portion WL, and between the lower surface portion 32 and the upper surface portion 34. A gap 16 is formed to reduce the weight.

  When assembling the underfloor portion 30 and the decorative portion 20, the decorative portion 20 is inserted in such a manner as to sandwich the lower surface portion 32 and the upper surface portion 34 of the underfloor portion 30. In the case of using a resin molded product as a material for forming the decorative portion 20 and the underfloor portion 30, due to the influence of dimensional errors that occur when molding both components, the fitting portion between both components is substantially omitted. It is impossible to finish the same dimension and fit like a metal workpiece.

  Therefore, in the present invention, the width of the decorative portion 20 is adjusted to the width of the under floor portion 30 by inserting the guide hook 24 on the decorative portion 20 side into the guide convex portion 44 formed on the under floor portion 30 side. The decorative portion 20 is deformed. As a result, positioning in the width direction is performed between the under floor portion 30 and the decorative portion 20, and the front lower wheel arch portion 22 of the decorative portion 20 spreads laterally, so that there is no gap between the vehicle body 4 and the front bumper 6. This prevents a problem that a gap is generated.

  In the state shown in FIG. 4, when the decorative portion 20 is inserted into the underfloor portion 30, the projection 45 that contacts the end surface of the guide hook 24 and serves as a stopper at the time of insertion is formed on the guide convex portion 44. It is formed at the back end. Furthermore, when the decorative portion 20 is inserted into the under floor portion 30, in order to position the under floor portion 30 and the decorative portion 20 in each portion, a rectangular shape is formed on the front bumper 6 side of the upper surface portion 34 in front of the vehicle body 4. The positioning boss 36 is projected. The positioning boss 36 is configured to be fitted into the fitting hole 26 opened in the upper surface portion of the decorative portion 20. The shape of the positioning boss 36 is not limited to a quadrangular shape, and a polygonal shape, a circular shape, or the like can be used.

  Furthermore, a fastening hole 38 through which a fastening screw 80 (see FIGS. 6 and 9) for fastening the front undercover 10 to the lower portion of the front bumper 6 is opened at the center of each positioning boss 36. Thus, by positioning the decorative portion 20 around the fastening hole 38, the front bumper 6 and the decorative portion 20 are more reliably positioned when the front under cover 10 is fastened to the lower portion of the front bumper 6, and the front bumper 6 and the decorative portion 20 can be easily generated and any level difference can be prevented.

  Even if the front bumper 6 or the decorative portion 20 is deformed by the wind pressure generated during traveling, the decorative portion 20 can follow the shape of the front bumper 6. In addition, the lower surface part 32 and the upper surface part 34 in the under floor part 30, and the decoration part 20 are fixed by fastening using the some blind rivet 14, for example. Thereby, even if it is a case where the front under cover 10 is comprised from two parts of the decoration part 20 and the under floor part 30, it can be handled as one assembly part. Moreover, the dimensional accuracy of the front under cover 10 can be improved by positioning and combining the two parts of the decorative portion 20 and the under floor portion 30.

  Rivet holes 28 through which blind rivets 14 for fixing the decorative portion 20 to the underfloor portion 30 are inserted are formed in the upper and lower surfaces of the decorative portion 20 and the upper surface portion 34 and the lower surface portion 32 of the underfloor portion 30. Has been. In the example shown in FIG. 2, only three blind rivets 14 and rivet holes 28 are shown in the left end portion of the vehicle 2 and the others are omitted. However, the rivet hole 28 has a U-shaped decorative portion in plan view. A number of blind rivets 14 are inserted along the rivet holes 28 to fix the under floor portion 30 and the decorative portion.

  In this way, by adopting a structure in which the decorative portion 20 is fixed to the under floor portion 30, when the pebbles collide with the decorative portion 20 during traveling of the vehicle 2 and the decorative portion 20 is damaged, or the decorative portion 20 becomes a curb. Even when the decorative portion 20 is damaged due to contact with the front, it is possible to replace only the damaged decorative portion 20 without replacing the entire front under cover 10 in an assembly manner. Since the appearance of the vehicle 2 is restored only by exchanging only the damaged decorative portion 20, it can be repaired at a low cost.

Next, a fixing structure between the under floor portion 30 and the decorative portion 20 and a fastening structure between the front bumper 6 and the front under cover 10 will be described with reference to FIGS.
6 is a cross-sectional view taken along the arrow VI-VI in a state after the decorative portion 20 is inserted and fixed to the under floor portion 30 shown in FIG. 2 and further fastened to the lower portion of the front bumper 6. FIG. -VII arrow sectional drawing, FIG. 8 is VIII-VIII arrow sectional drawing, FIG. 9 is VV arrow sectional drawing.

  As shown in FIGS. 6 to 9, the front under cover 10 includes a decorative portion 20 that forms the outer lower peripheral surface of the front bumper 6 and an under floor portion 30 that forms a part of the lower surface of the vehicle body.

  Among these, the under floor part 30 is comprised from the lower surface part 32 which forms the lower surface of the vehicle body 4, and the upper surface part 34 which faces the engine compartment lower part of the vehicle 2, and the lower surface part 32 and the upper surface part 34 are under floor parts. They are crimped and fixed to each other at the crimping part WL of the connecting part 11 formed on the outer peripheral edge of 30. Thus, by forming the space 16 in the closed space between the lower surface portion 32 and the upper surface portion 34, the under floor portion 30 can be integrally formed by blow molding. A blow molded product can produce a product having high rigidity at a relatively low cost while being relatively thin and light. In the embodiment shown in FIG. 6, the crimping portion WL is formed on a mating surface (parting line) between a mold for molding the lower surface portion 32 of the under floor portion 30 and a mold for molding the upper surface portion 34. Yes.

  Further, by molding the decorative portion 20 by resin injection molding, the dimensional accuracy can be increased with light weight, and the appearance of the portion appearing on the surface of the vehicle 2 can be finely finished.

  Further, as shown in FIG. 6, a fitting hole 26 opened on the upper surface of the decorative portion 20 is fitted into the positioning boss 36 protruding from the upper surface of the under floor portion 30. Thereby, the under floor part 30 and the decoration part 20 can be positioned by components. Further, the front bumper 6 and the decorative portion 20 are accurately connected by fastening the front under cover 10 to the lower part of the front bumper 6 using a fastening screw 80 (for example, a tapping screw) and a clip 82 at the center of the positioning boss 36. Can be matched well. Furthermore, as shown in FIG. 6, the crimping portion WL (one form of the connecting portion 11) of the under floor portion 30 formed by blow molding is relatively fastened to the front bumper 6 using a direct fastening screw 80. The pressure-bonding portion WL that is vulnerable to impact can be protected from the outside, and damage to the pressure-bonding portion WL can be prevented.

  A grommet 84 is attached to the opening provided on the lower surface of the decorative portion 20. When the front under cover 10 is fastened to the front bumper 6, the grommet 84 is removed downward, the fastening screw 80 is inserted through the opening, and the fastening screw 80 is screwed to the clip 82 using a tool. When the fastening screw 80 has been fastened, the tool is pulled out, the grommet 84 is inserted into the opening on the lower surface of the decorative portion 20 to close the opening, and the dust enters or flows into the lower surface of the front under cover 10. Prevents disturbance of the airflow AF.

  Further, as shown in FIG. 11 when explaining the background art, when all of the front under cover 110 is integrally formed by blow molding, the fastening position LF1 between the lower portion of the front bumper 106 and the front under cover 110 is inevitably set. However, according to the present invention, the fastening position LF2 between the lower portion of the front bumper 6 and the front under cover 10 can be shortened as shown in FIG. 6 (that is, LF1> LF2). Accordingly, it is possible to improve the mounting rigidity of the front under cover 10 with respect to the front bumper 6, and even when wind pressure or vibration occurs during traveling, a gap is hardly generated between the front bumper 6 and the front under cover 10. Thus, problems such as resonance of the front under cover 10 can be reduced.

  Further, according to the present invention, even when the height H of the decorative portion 20 is increased, there is no need to provide the opening 125 for forming the draft taper 123 as shown in FIG. Disturbance of the airflow AF of the air flowing through can be prevented. As a result, the air resistance of the vehicle can be reduced, and the lift applied to the vehicle can also be reduced.

Next, the structure of the decoration part 20 and the under floor part 30, and the position of the parting line PL will be described with reference to FIG.
As shown in FIG. 7, the front under cover 10 uses the upper surface portion and the lower surface portion of the decorative portion 20 to cover the connecting portion 11 of the under floor portion 30 formed by blow molding, so that the lower surface portion of the under floor portion 30 is covered. 32 and the upper surface portion 34. Blind rivets 14 are used to fix the under floor portion 30 and the decorative portion. By configuring the front under cover 10 in this way, a structure in which the space 16 and the space 17 formed inside the front under cover 10 are partitioned by the lower surface portion 32 or the upper surface portion 34 can be achieved. Therefore, it is possible to reduce the weight while maintaining the rigidity and strength of the front undercover 10.

  Further, when the decorative part 20 is formed by injection molding, as shown in FIG. 7, the parting lines PL1 and PL2 of the mold for forming the decorative part 20 can be arranged at positions that are not visible from the outside. . Thereby, the external appearance of the front undercover 10 can be finished beautifully and the texture can be improved. Moreover, since the parting line PL3 of the under floor part 30 is also covered with the decoration part 20, it can be hidden between the upper surface part and the lower surface part of the decoration part 20, so that the appearance of the front under cover 10 is finished beautifully. be able to.

Next, the relationship between the continuous recessed part 29 formed in the inner surface side of the decoration part 20 and the connection part 11 is demonstrated using FIG.
As shown in FIG. 8, a continuous recess 29 that extends continuously in parallel with the lower surface of the vehicle body 4 is formed on the inner surface of the decorative portion 20 on the under floor portion 30 side. On the front side of the continuous recess 29, a step shape 12 of the front under cover 10 simulating a front side wing is formed. The continuous concave portion 29 and the connecting portion 11 are arranged close to the opposed positions.

  Thus, by arranging the continuous concave portion 29 and the connecting portion 11 close to the facing position, the continuous concave portion 29 and the connecting portion 11 can be easily engaged with each other, and the decorative portion is caused by wind pressure or impact during traveling. When 20 is deformed inward, the inner side of the decorative portion 20 contacts the connecting portion 11, so that further deformation of the decorative portion 20 can be suppressed, and generation and breakage of vibration can be prevented.

  In addition, since the resin crimping part WL formed at the time of blow molding is covered with the decorative part 20, the case where the front lower part of the vehicle 2 is brought into contact with the curb stone or the jumped pebbles collide with the decorative part 20. Even if it exists, since force is applied only to the crimping part WL through the decorative part 20, it is possible to prevent the crimping part WL from being relatively weak against impact.

Next, an embodiment in which a bumper contact portion 27 is formed at the upper end portion of the decorative portion 20 that comes into contact with the lower portion of the front bumper 6 will be described with reference to FIG.
As shown in FIG. 9, a bumper contact portion 27 for contacting the lower portion of the front bumper 6 is formed at the upper end portion of the decorative portion 20 on the front bumper 6 side. Thereby, positioning of the decoration part 20 with respect to the front bumper 6 can be performed. Further, the bumper contact portion 27 is sandwiched between the guide convex portion 44 formed at the upper end portion of the under floor portion 30 and the front bumper 6, and the lower end portion of the front bumper 6 and the under bump portion 6 are clamped by a fastening screw 80 and a clip 82 in the vicinity thereof. The upper end portion of the floor portion 30 is fastened. Thereby, the front bumper 6 lower part and the front under cover 10 can be fastened with high accuracy without generating a gap between the front bumper 6 and the decorative portion 20.

Next, an example of the manufacturing process of the front undercover 10 will be described with reference to FIG.
Since the front under cover 10 according to the present invention is composed of two parts, the decorative portion 20 and the under floor portion 30, each can be manufactured independently in the first stage. First, the decoration part 20 shape | molds a base | substrate by injection molding in process S102 (it abbreviate | omits and describes as S102 hereafter). As the base material, a resin such as polypropylene or urethane can be used.

  In the next step S104, a coating ground treatment is performed on the decorative portion 20 after injection molding, and coating (surface treatment) is performed in a range including a portion exposed on the side surface of the vehicle 2. The paint color has variations of each color as well as the body color. In addition, according to this invention, since it is only necessary to surface-treat only about the decoration part 20 except the under floor part 30, the handling of the product in a surface treatment process becomes easy and productivity improves. In addition, a small surface treatment facility can be used. When the surface treatment is completed, the decorative portion 20 is completed and supplied to the assembly step (S130) with the under floor portion 30.

  One under floor portion 30 forms the base body by blow molding in S122. When the molding of the mother body is completed, in S124, after removing the burr and the bottom burr generated at the time of blow molding, trimming for the purpose of removing the burr is performed around the crimping part WL.

  In the next S126, processing is performed to open a rivet hole 28 for fixing the decorative portion 20, a fastening hole 38 (see FIG. 2) for fastening to the lower part of the front bumper 6 of the vehicle 2, and the like as necessary. Then, a process for driving a washer for reinforcing the fastening part is performed. When the processing in S126 is completed, the underfloor portion 30 is completed.

  Next, in S128, the completed under floor portion 30 is fastened to an assembly jig to correct the deformation after blow molding. In the next S130, the decorative portion 20 is inserted and assembled so as to sandwich the lower surface portion 32 and the upper surface portion 34 of the under floor portion 30 from the front of the under floor portion 30 (FIGS. 2 and 2). 3).

  In addition, the guide hooks 24 having a concave cross section formed at the upper ends of the left and right ends of the decorative portion 20 are fitted into the guide convex portions 44 having a convex cross section formed at the upper end of the under floor portion 30. Positioning in the left-right direction (the width direction of the vehicle 2) is performed. And the decoration part 20 is made to fit in the under floor part 30 until the end surface of the guide hook 24 contacts the projection part 45 of the under floor part 30.

  Then, a positioning boss 36 formed at the front end of the upper surface portion 34 of the under floor portion 30 is inserted into the insertion hole 26 of the decorative portion 20 to position both components. And the decoration part 20 and the under floor part 30 are fixed using the blind rivet 14, and the assembly of the front under cover 10 is completed.

  In next step S132, the assembled front under cover 10 is inspected for dimensions and appearance, and only products that fall within a predetermined tolerance range are shipped as finished products.

  The under floor portion 30 is molded by blow molding in S122, and the lower surface portion 32 and the upper surface portion 34 are separately molded by vacuum molding or the like, and then both members are pressure-bonded by the connecting portion 11, It is also possible to form the floor portion 30.

  In the above embodiment, an example in which the vehicle body under cover according to the present invention is applied to the front under cover 10 has been described. However, the present invention can also be applied to the rear under cover 60 and the side spoiler 70.

1 is an external perspective view of a box-type passenger car equipped with a vehicle body undercover according to the present invention. It is a disassembled perspective view at the time of applying the undercover for vehicle bodies concerning this invention to a front undercover. It is the expansion perspective view which observed the front undercover shown in Drawing 2 from the other direction. It is IV arrow directional view of the front lower wheel arch part shown in FIG. 2, and is a perspective view which shows the state after inserting and fixing a decoration part to an under floor part. FIG. 5 is a cross-sectional view taken along line VV shown in FIG. 4. It is VI-VI arrow sectional drawing in the state after assembling the under floor part and decoration part which were shown in FIG. 2, and also fastening to the front bumper lower part. FIG. 5 is a cross-sectional view taken along the line VII-VII in a state after assembling the under floor portion and the decorative portion shown in FIG. 2 and fastening the under floor portion and the lower portion of the front bumper. It is a VIII-VIII arrow sectional view in the state after assembling the under floor part and decoration part shown in Drawing 2, and also fastening to the lower part of a front bumper. FIG. 5 is a cross-sectional view taken along line VV in FIG. 4 in a state after assembling the under floor part and the decoration part and further fastening the under floor part and the decoration part to the lower part of the front bumper. It is process drawing which shows one Example of the manufacturing process of a front undercover. It is a figure explaining the malfunction which arises when the height of a decoration part is designed high in the front undercover which employ | adopted the conventional structure.

Explanation of symbols

2 Vehicle 4 Car body 5 Wheel 6,106 Front bumper 8 Rear bumper 10, 110 Front under cover 11 Connecting portion 12 Step shape 14 Blind rivet 16, 17, 116 Gap 20 Decoration portion 22 Front lower wheel arch portion 24 Guide hook 26 Fit hole 27 , 127 Bumper contact portion 28 Rivet hole 29 Continuous recess 30, 130 Under floor portion 32, 132 Lower surface portion 34, 134 Upper surface portion 36 Positioning boss 38 Fastening hole 44 Guide convex portion 45 Projection portion 60 Rear under cover 70 Side spoiler 80 Fastening Screw 82 Clip 85 Grommet 120 Decoration surface 123 Draw taper 125 Opening AF Air flow WL Crimping part PL Parting line

Claims (7)

A vehicle body undercover having a decorative portion that forms a part of the outer lower peripheral surface of the vehicle body and an under floor portion that forms a part of the lower surface of the vehicle body,
The underfloor portion is a lower surface portion, an upper surface portion disposed above the lower surface portion with a gap between the lower surface portion, and a connecting portion that integrally connects the lower surface portion and the outer peripheral edge of the upper surface portion. And
The underbody cover for a vehicle body, wherein the decorative portion is fixed so as to cover the connecting portion of the under floor portion and sandwich the lower surface portion and the upper surface portion. The connecting portion is composed of a crimping portion protruding outward between the outer peripheral edges,
The under cover for a vehicle body according to claim 1, wherein an inner side surface of the decorative portion on the under floor portion side and the crimping portion are close to each other. On the inner surface on the under floor portion side of the decorative portion, a continuous recess that extends continuously in parallel with the lower surface of the vehicle body is formed.
The under cover for a vehicle body according to claim 2, wherein the crimping portion and the continuous recess in the under floor portion are arranged to face each other. The vehicle body undercover is fastened to a lower portion of a bumper that covers a front end lower portion of a vehicle body or a rear end lower portion to a side lower portion of the vehicle body that reaches the wheel arch,
At the upper end on the wheel arch side of the decorative portion and on the bumper side, the upper end portion on the bumper side is folded back from the inner surface of the decorative portion to the under floor portion side substantially parallel to the inner surface of the decorative portion. A guide hook having a concave cross section is formed,
The guide convex part of the cross-sectional convex shape for fitting in the said guide hook is formed in the wheel arch side in the said under floor part, and the said bumper side upper end part, The 1-3 characterized by the above-mentioned. Under cover for car body as described in 4.   5. The vehicle body according to claim 4, wherein a bumper contact portion that positions the bumper by contacting the lower portion of the bumper is formed at an upper end portion on the bumper side of the decoration portion. For undercover.   The undercover for a vehicle body according to claim 4 or 5, wherein the lower surface portion includes a rectifying plate that regulates an airflow flowing on a lower surface of the vehicle body. Forming the decorative part according to claim 1 by injection molding using a resin material;
The step of integrally forming the upper surface portion and the lower surface portion of the under floor portion according to claim 1 by blow molding using a resin material,
Fixing the decorative portion and the under floor portion using a rivet;
The manufacturing method of the undercover for vehicle bodies characterized by including.

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