JP2024110215A - Vehicle underbody structure - Google Patents

Abstract

[Problem] To protect peripheral devices located in the front of the vehicle, which are a heat source, below the rear floor panel. [Solution] A rear floor cover 18 is provided below the rear floor panel 12, next to the vehicle rear of a muffler 16, which is a heat source, and has a front surface 24 facing the muffler 16, and an opening 26 is provided on this front surface 24, which makes it easier for heat (hot air) from the muffler 16 to escape through the opening 26 into a space S inside the rear floor cover 18. Since it is possible to prevent heat generated from the muffler 16 from circulating around to the front of the vehicle, it is advantageous in preventing thermal damage to peripheral devices such as a fuel tank 14 located in front of the muffler 16 and protecting the peripheral devices. [Selected Figure] Figure 2

Description

The present invention relates to a vehicle undercarriage.

2. Description of the Related Art In order to improve the aerodynamic performance of a vehicle while it is in motion, a rear floor cover (also called an undercover) is attached below the rear floor panel of the vehicle.
The rear floor cover is disposed in front of the rear bumper and has a front surface facing the front of the vehicle and a bottom surface extending from the lower end of the front surface toward the rear of the vehicle toward the rear bumper (see Patent Document 1).

JP 2020-40610 A

Incidentally, for example, in a vehicle using an engine as a drive source, a heat source such as a muffler may be disposed adjacent to the vehicle front of the rear floor cover below the rear floor panel.
In this case, there is a concern that the heat emitted from the heat source will be blocked by the front surface of the rear floor cover, causing the heat to accumulate around the heat source, causing thermal damage to peripheral equipment located in front of the heat source below the rear floor panel.
The present invention has been made in consideration of the above circumstances, and has an object to provide a vehicle underbody structure that is advantageous in protecting peripheral equipment located below the rear floor panel and in front of the vehicle, which is a heat source.

In order to achieve the above object, one embodiment of the present invention is a vehicle underbody structure including a heat source provided below a rear floor panel, and a rear floor cover provided below the rear floor panel and in line with the heat source to the rear of the vehicle, covering the rear floor panel from below, the rear floor cover having a front surface that extends in the vertical and width directions of the vehicle and faces the heat source, and an opening is provided on the front surface.

According to one embodiment of the present invention, a rear floor cover located below the rear floor panel and behind the heat source has a front surface facing the heat source, and an opening is provided on this front surface, so that heat (hot air) from the heat source can easily escape into the space inside the rear floor cover through the opening.
Therefore, heat generated from the heat source can be prevented from flowing around to the front of the vehicle, which is advantageous in preventing thermal damage to peripheral equipment located in front of the heat source and protecting the peripheral equipment.

FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. 2 is a perspective view of a rear floor cover attached to the underside of the vehicle, as viewed from below and in front of the vehicle. FIG. 2 is a perspective view of the rear floor cover as viewed from above the front of the vehicle. FIG. 2 is a perspective view of the rear floor cover as viewed from above at the rear of the vehicle. FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In the drawings, the arrow UP indicates the upper side of the vehicle, the arrow FR indicates the front side of the vehicle, the arrow IN indicates the inner side in the vehicle width direction, and the arrow OUT indicates the outer side in the vehicle width direction.
As shown in FIGS. 1 and 2, a rear floor panel 12 extending in the vehicle front-rear direction and in the vehicle width direction is provided at the rear of a vehicle 10.
Below the rear floor panel 12, a fuel tank 14, a muffler 16, and a rear floor cover 18 are arranged in this order from the front to the rear of the vehicle.
In addition, a rear bumper 20 is provided behind the rear floor cover 18 .
The rear bumper 20 has a bumper rear surface 2002 that covers the rear of the rear floor cover 18 and the rear of the rear floor panel 12 over the entire length in the vehicle width direction, and a bumper lower surface 2004 that extends from the lower end of the bumper rear surface 2002 toward the front of the vehicle.
A bumper beam (not shown) extends inside the rear bumper 20 in the vehicle width direction.

The fuel tank 14 is disposed adjacent to the muffler 16 at the front of the vehicle and is provided approximately in the center in the vehicle width direction. In this embodiment, the fuel tank 14 is a peripheral device disposed at the front of the muffler 16.
The fuel tank 14 has a width in the vehicle width direction, a length in the vehicle front-rear direction, and a height in the up-down direction.
The fuel tank 14 is attached to vehicle frame members such as cross members and side members via stays (not shown).
The muffler 16 has a length along the vehicle width direction, a width along the vehicle front-rear direction, and a height in the up-down direction. In this embodiment, the muffler 16 has an elliptical shape with its major axis oriented in the vehicle front-rear direction when viewed in the vehicle width direction.
The muffler 16 serves to reduce the temperature and pressure of high-temperature, high-pressure exhaust gas discharged from an engine (not shown) while the vehicle is running, thereby suppressing exhaust noise. The temperature of the muffler 16 can reach high temperatures, for example several hundred degrees, depending on the location, and therefore the muffler 16 is a heat source that reaches high temperatures.
Reference numeral 22 in the drawing denotes a heat protector provided above the muffler 16 so as to cover the underside of the rear floor panel 12. The heat protector 22 is intended to protect peripheral devices (not shown) arranged on the upper surface of the rear floor panel 12 from heat damage caused by the muffler 16.

The rear floor cover 18 is a component for improving the aerodynamic performance of the vehicle 10 while it is moving, and is provided below the rear floor panel 12, next to the muffler 16 and to the rear of the vehicle, with the rear floor cover 18 covering the rear floor panel 12 from below.
In this embodiment, the rear floor cover 18 is made of synthetic resin.
As shown in FIGS. 1 to 5, the rear floor cover 18 includes a front surface 24 , a bottom surface 28 , and a pair of side surfaces 30 .
The front surface 24 faces the muffler 16 and extends in the vertical direction and in the vehicle width direction.
The width of the front surface 24 in the vehicle width direction is formed to be larger than the widths of the muffler 16 and the fuel tank 14 .
An opening 26 is provided at the top of the front surface 24 .
The opening 26 is provided by removing a portion including the upper edge of the front surface 24, so that the opening 26 is open upward.
The opening 26 has a uniform depth and extends over almost the entire length of the front surface 24 in the vehicle width direction, with portions of the front surface 24 remaining on both sides of the extension direction of the opening 26.

The bottom surface 28 extends from the lower end of the front surface 24 toward the rear of the vehicle, and the bottom surface 28 has a width in the vehicle width direction that is approximately the same as that of the front surface 24.
In this embodiment, when the rear floor cover 18 is attached to the vehicle 10, the bottom surface 28 extends on a substantially horizontal plane.
As shown in FIG. 3 , a towing hook hole 32 that is open to the rear of the vehicle is provided in the bottom surface 28 at approximately the center in the vehicle width direction at the rear end of the vehicle, and a towing hook 34 is exposed downward from the towing hook hole 32.
The pair of side surfaces 30 connect both ends of the front surface 24 in the vehicle width direction to both ends of the bottom surface 28 in the vehicle width direction.
The pair of side surfaces 30 extend in the vehicle front-rear direction and in the up-down direction, and face each other in the vehicle width direction.

In this embodiment, the rear floor cover 18 is attached to the vehicle 10 by attaching the rear floor cover 18 to the rear floor panel 12 and the bumper beam with the bottom surface 28 of the rear floor cover 18 near the rear end of the vehicle overlapping the underside of the bumper 2004 from above, as shown in Figure 2.
More specifically, as shown in FIG. 3, a first attachment piece 36 protruding from an upper end of the front surface 24 near one end in the vehicle width direction is fastened to the underside of the rear floor panel 12 by a bolt.
As shown in FIG. 5, bolts that have passed through mounting holes 2010, 2012 in the bumper underside 2004 shown in FIG. 3 are inserted into first and second mounting holes 38A, 38B provided in the bottom surface 28 at locations toward the rear end of the vehicle on either side of the towing hook hole 32 in the vehicle width direction, and are fastened together to a bracket (not shown) provided on the bumper beam.
As shown in FIG. 4 , a second mounting piece 40 protrudes upward from a location near the other end in the vehicle width direction at the rear end of the bottom surface 28, and this second mounting piece 40 is fastened with a bolt to a bracket (not shown) provided on the bumper beam inside the rear bumper 20.
Incidentally, various conventionally known structures can be adopted as the assembly structure for the rear floor cover 18.

As shown in Figure 2, when the rear floor cover 18 is assembled to the vehicle 10 below the rear floor panel 12, a space S is formed between the rear floor cover 18 and the rear floor panel 12 and the rear bumper 20, i.e., inside the rear floor cover 18, extending in the fore-and-aft, width-wise, and up-and-down directions of the vehicle.
Furthermore, when the rear floor cover 18 is attached to the vehicle 10 below the rear floor panel 12 , a certain amount of gap is formed between the upper edge of the rear floor cover 18 and the rear floor panel 12 .

Next, the effects will be described.
According to this embodiment, the rear floor cover 18, which is arranged below the rear floor panel 12 and next to the rear of the muffler 16, which is a heat source, has a front surface 24 facing the muffler 16, and an opening 26 is provided on this front surface 24, so that heat (hot air) from the muffler 16 can easily escape into the space S inside the rear floor cover 18 through the opening 26.
Therefore, since the heat generated from the muffler 16 can be prevented from flowing around to the front of the vehicle, it is advantageous for preventing thermal damage to peripheral equipment such as the fuel tank 14 located in front of the muffler 16 and protecting the peripheral equipment, which is advantageous for preventing deterioration and breakdowns of the peripheral equipment.
In particular, when the engine is idling, the air flow below the vehicle 10 stops, so the heat generated from the muffler 16 tends to flow around to the front of the vehicle, raising concerns about thermal damage to peripheral equipment located in front of the muffler 16.
Even in such a case, according to this embodiment, heat (hot air) from the muffler 16 can be released through the opening 26 into the space S inside the rear floor cover 18, which is advantageous in reducing thermal damage to peripheral equipment located in front of the muffler 16 and protecting the peripheral equipment.

In addition, in this embodiment, the opening 26 is located at the upper part of the front surface 24, and therefore the opening 26 is located away from the air flowing underneath the vehicle 10 when the vehicle 10 is moving.
This is advantageous in reducing the effect that the opening 26 has on the air flowing underneath the vehicle 10 while it is moving, and is advantageous in ensuring the aerodynamic performance of the vehicle 10.

In addition, in this embodiment, the opening 26 extends over almost the entire length of the front surface 24 in the vehicle width direction, so that a large area of the opening 26 can be secured and heat from the muffler 16 can be efficiently dissipated through the opening 26 into the space S of the rear floor cover 18, which is more advantageous in preventing thermal damage to peripheral equipment located in front of the muffler 16 and protecting the peripheral equipment.
In addition, the work of assembling the rear floor cover 18 to the vehicle 10 involves placing the rear end of the bottom surface 28 of the rear floor cover 18 on the bumper underside 2004 of the rear bumper 20, and using the rear end of the bottom surface 28 as a fulcrum, swinging the front portion of the rear floor cover 18 from below to above.
In this embodiment, the opening 26 extends at the top of the front surface 24 over almost the entire length of the front surface 24 in the vehicle width direction, and therefore the opening 26 prevents interference between the front surface 24 of the rear floor cover 18 and the muffler 16, which is advantageous in improving the efficiency of the assembly work of the rear floor cover 18.
It should be noted that in order to prevent interference between the front surface 24 of the rear floor cover 18 and the muffler 16 during the assembly process, it is also possible to shorten the length of the rear floor cover 18 in the longitudinal direction of the vehicle.
However, in that case, the length of the bottom surface 28 in the fore-and-aft direction of the vehicle would be shortened, which would be disadvantageous in terms of ensuring the aerodynamic performance of the vehicle 10.
In contrast to this, in the present embodiment, by providing an opening 26, it is possible to improve the efficiency of the assembly work of the rear floor cover 18 while advantageously ensuring the aerodynamic performance of the vehicle 10 without shortening the length of the bottom surface 28 in the fore-and-aft direction of the vehicle.

In addition, in this embodiment, when the rear floor cover 18 is assembled to the vehicle, heat that escapes into the space S through the gap formed between the upper edge of the rear floor cover 18 and the rear floor panel 12 will escape, albeit in small amounts, to the outside of the rear floor cover 18.
However, as in the present embodiment, when a bottom surface 28 is formed extending from the lower end of the front surface 24 to the rear of the vehicle and a towing hook hole 32 is provided in the bottom surface 28 to expose the towing hook 34, this is advantageous in efficiently dissipating heat that has escaped from the muffler 16 into the space S of the rear floor cover 18 through the towing hook hole 32 to the outside of the rear floor cover 18.
As a result, heat is less likely to build up in the space S of the rear floor cover 18, which is more advantageous in efficiently dissipating heat from the muffler 16 into the space S of the rear floor cover 18 through the opening 26, and is even more advantageous in preventing thermal damage to peripheral equipment and protecting the peripheral equipment.

In addition, in this embodiment, the heat source is configured as the muffler 16, and the fuel tank 14 is located adjacent to the muffler 16 in front of the vehicle, which is advantageous in suppressing thermal damage to the fuel tank 14 caused by the muffler 16 and protecting the fuel tank 14.

In this embodiment, the heat source is described as the muffler 16, but the heat source may include various conventionally known components and devices that become hot as the vehicle is operating, such as an exhaust pipe.
In addition, in this embodiment, the case has been described in which the peripheral device arranged adjacent to the heat source at the front of the vehicle is the fuel tank 14, but the peripheral device includes various conventionally known devices and components that are susceptible to heat damage, such as a battery pack and electrical components.

10 vehicle 12 rear floor panel 14 fuel tank (peripheral equipment)
16 Muffler (heat source)
Reference Signs List 18 Rear floor cover 20 Rear bumper 2002 Bumper rear surface 2004 Bumper lower surface 2010, 2012 Mounting hole 22 Heat protector 24 Front surface 26 Opening 28 Bottom surface 30 Pair of side surfaces 32 Towing hook hole 34 Towing hook 36 First mounting piece 38A First mounting hole 38B Second mounting hole 40 Second mounting piece S Space

Claims (5)

A heat source provided under the rear floor panel;
a rear floor cover that is provided below the rear floor panel and aligned with the heat source to the vehicle rear, and covers the rear floor panel from below,
the rear floor cover has a front surface extending in a vertical direction and a vehicle width direction and facing the heat source,
The front surface is provided with an opening.
A vehicle underbody structure comprising: The opening is located at the top of the front surface.
2. The vehicle underbody structure according to claim 1. The opening extends over substantially the entire length of the front surface in the vehicle width direction.
3. The vehicle underbody structure according to claim 2. A bottom surface is formed extending from a lower end of the front surface toward the rear of the vehicle,
A towing hook hole is provided on the bottom surface to expose the towing hook.
2. The vehicle underbody structure according to claim 1. The heat source comprises a muffler,
A fuel tank is disposed adjacent to the muffler in front of the vehicle.
2. The vehicle underbody structure according to claim 1.

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