JP2019189102A - Rear part vehicle body structure for vehicle - Google Patents

Abstract

To provide a rear part vehicle body structure for a vehicle capable of reducing travel resistance caused by a rear flow vortex generated on a vehicle rear side.SOLUTION: A rear part vehicle body structure of a vehicle V includes: rear window glass 12; a spoiler 20 which covers an upper end side portion of the rear window glass 12; and a lift gate 1 which can open/close a rear cargo room opening. The spoiler 20 has a roof spoiler 21 extending to right and left sides and a pair of right and left side spoilers 22 which extends downward from both ends on right and left sides of the roof spoiler 21, respectively. A rear side edge section 22e of the side spoiler 22 is formed to extend upward from middle step sections of right and left ends of the rear window glass 12 and to be substantially orthogonal to a vehicle body longitudinal direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rear body structure of a vehicle, and more particularly to a rear body structure of a vehicle having a spoiler that covers an upper end side portion of a rear window glass.

Conventionally, many rear spoilers have been put to practical use in order to reduce air resistance, which is a main item related to improvement in vehicle performance and fuel consumption.
Usually, the rear spoiler includes a roof spoiler that covers an upper end portion of the rear window glass and extends in the vehicle width direction, and a pair of left and right side spoilers that extend downward from the left and right ends of the roof spoiler.

As shown in FIG. 10, an air flow (hereinafter referred to as a side wall airflow) that flows on the upper surface of the vehicle body is caught in an air flow (hereinafter referred to as a roof airflow) that flows on the top surface of the vehicle in the rear region of the vehicle that is running. A pair of left and right wake vortices (also called trailing vortexes) extending spirally are formed. The region sandwiched between the pair of wake vortices forms a negative pressure region (dead water region) in which almost no air moves. Therefore, a drag force acting backward is applied to the vehicle, resulting in a loss of kinetic energy. It has become a big factor.
The rear spoiler has a function of suppressing (reducing) a wake vortex generated at the rear of the vehicle by peeling off the roof airflow and the side wall airflow from the vehicle body at once using the roof spoiler and the side spoiler.

  The rear body structure of an automobile disclosed in Patent Document 1 includes a roof spoiler extending in the vehicle width direction and a pair of left and right side spoilers extending downward from the left and right ends of the roof spoiler, respectively, and the side surface of the side spoiler in the vehicle width direction. Further, an outer ridge line portion for separating the side wall airflow is extended in the up-down direction, and an extension portion that includes the inner ridge line portion and extends rearward is formed on the inner side in the vehicle width direction than the protrusion of the ridge line portion. As a result, the outer ridge line part immediately peels off the side wall airflow and the inward transverse wind is peeled off at the inner ridge line part to improve the aerodynamic characteristics.

JP 2017-078771 A

The rear body structure of the automobile of Patent Document 1 can improve aerodynamic characteristics by causing the outer ridge line portion to immediately peel the side wall airflow.
However, as in Patent Document 1, when the rear edge of the side spoiler is formed so as to move downward toward the rear side, the kinetic energy loss may not be sufficiently reduced.

As a result of examination by the present inventors, it has been found that a wake vortex is generated based on the speed difference between the high-speed roof airflow and the low-speed side wall airflow, and the wake vortex becomes larger (stronger) as the speed difference between these airflows increases. .
In other words, the flow velocity of the side wall airflow gradually decreases as the side wall airflow flowing rearward in the vicinity of the roof side rail gradually separates from the upper end portion of the rear edge of the side spoiler along the lower end portion. As a result, the side wall airflow caught in the roof airflow increases, and as a result, the effect of suppressing the generation of the wake vortex is diminished.
Therefore, in order to secure the effect of suppressing the generation of the wake vortex that becomes the running resistance, further improvement is required for the rear body structure of the vehicle.

  An object of the present invention is to provide a rear body structure or the like of a vehicle that can reduce running resistance caused by a wake vortex generated behind the vehicle.

  The rear body structure of a vehicle according to claim 1 is a rear body structure of a vehicle that includes a rear window glass and a spoiler that covers an upper end portion of the rear window glass and includes a lift gate that can open and close the rear luggage compartment opening. The spoiler includes a roof spoiler that extends in the vehicle width direction and a pair of left and right side spoilers that extend downward from the left and right ends of the roof spoiler, and the rear edge of the side spoiler includes the rear winder It is characterized in that it is formed so as to extend upward from the middle step in the vehicle width direction end of the glass and to be substantially orthogonal to the longitudinal direction of the vehicle body.

In this vehicle rear body structure, the spoiler has a roof spoiler extending in the vehicle width direction and a pair of left and right side spoilers extending downward from the left and right ends of the roof spoiler, and thus acts on the rear window glass. While reducing lift and drag, the roof airflow flowing on the roof upper surface can be peeled off from the rear edge of the roof spoiler, and the side wall airflow flowing on the vehicle body side wall upper surface can be peeled off from the rear edge of the side spoiler.
The rear edge of the side spoiler extends upward from the middle step of the rear window glass in the vehicle width direction and is formed so as to be substantially perpendicular to the longitudinal direction of the vehicle body, so that it flows in the vicinity of the roof side rail. By separating the side wall airflow from the vehicle body at substantially the same time, a decrease in flow velocity can be suppressed, and the side wall airflow caught in the roof airflow can be reduced.

The invention of claim 2 is characterized in that, in the invention of claim 1, an upper end portion of the rear side edge portion is arranged in front of a rear end portion of the roof spoiler.
According to this configuration, the separation timing of the side wall airflow can be made earlier than the separation timing of the roof airflow, and the side wall airflow caught in the roof airflow can be further reduced.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the vehicle has a pair of left and right roof side rails extending in the vehicle front-rear direction, and extends in the vehicle width direction at a vehicle width direction outer portion of the roof side rail. A groove portion recessed inward is formed, and the side spoiler is disposed on a rearward extension line of the groove portion.
According to this configuration, since the side wall airflow flowing in the vicinity of the roof side rails is gathered via the groove portion, the side wall airflow is increased before the side airflow reaches the rear edge of the side spoiler, and the roof airflow is increased. The speed difference of the side wall airflow can be reduced, and the collected side wall airflow can be forcibly guided to the rear edge of the side spoiler.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the rear edge includes a distance from a predetermined reference point to an upper end set at the rear of the vehicle and a lower end from the reference point. It is characterized in that it is formed so that the distances to the parts are substantially equal.
According to this configuration, the angle of the rear edge of the side spoiler can be easily set.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the rear edge separates a roof airflow flowing on the upper surface of the vehicle body roof and a side wall airflow flowing on the upper surface of the vehicle body side wall as the vehicle travels. It is characterized by being formed as follows.
According to this configuration, the side wall airflow and the roof airflow can be reliably divided, and the influence of the wake vortex can be suppressed.

  According to the rear vehicle body structure of the vehicle of the present invention, it is possible to reduce running resistance caused by a wake vortex generated behind the vehicle.

1 is a perspective view of a rear body structure of a vehicle according to a first embodiment. It is a left side view. It is a top view. It is the IV-IV sectional view taken on the line of FIG. It is a principal part enlarged view of FIG. It is a perspective view of a rear spoiler. It is explanatory drawing of the setting method which concerns on the rear edge part of a side spoiler. It is an analysis result of the back stream concerning a comparative example model. It is an analysis result of the back air flow concerning an example model. It is explanatory drawing of a wake vortex.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its application, or its use.

Embodiment 1 of the present invention will be described below with reference to FIGS.
As shown in FIGS. 1 to 3, the vehicle V of the present embodiment is a four-door hatchback type passenger car having a flip-up type lift gate 1 at the rear of the vehicle body.
In the following description, the arrow F direction is the front side, the arrow L direction is the left side, and the arrow U direction is the upper side.

First, the basic configuration of the vehicle V will be described.
As shown in FIGS. 1 to 3, the vehicle V includes a pair of left and right front pillars 2 that support a front window glass, a pair of left and right center pillars (not shown), and a pair of left and right rear pillars 3. The roof portion 4 is supported by these pillars.
A front door 5 is pivotally supported between the front pillar 2 and the center pillar, and a rear door 6 is pivotally supported between the center pillar and the rear pillar 3.

  A front fender 7 connected to the front pillar 2 is disposed in the lower front portion of the front pillar 2, and a rear fender 8 connected to the rear pillar 3 is disposed in the rear lower region of the rear pillar 3. The front pillar 2, the rear pillar 3, the front door 5, the outer panel of the rear door 6, the front fender 7, and the rear fender 8 constitute a pair of left and right side panels S corresponding to the side wall of the vehicle V.

  The roof portion 4 includes a pair of left and right roof side rails 9 extending front and rear, a front header (not shown) that connects the front end portions of the pair of roof side rails 9, and a rear of the pair of roof side rails 9. A rear header (not shown) that connects the end portions and a substantially rectangular roof panel 10 that covers the entire space between the pair of roof side rails 9 from the upper side are provided.

As shown in FIG. 3, the pair of roof side rails 9 are formed so that the separation distance in the vehicle width direction becomes narrower toward the rear side.
As shown in FIG. 4, the roof side rail 9 includes a roof side outer 9 a disposed on the outer side in the vehicle width direction, and a roof side inner 9 b that forms a closed section extending in the front-rear direction in cooperation with the roof side outer 9 a. have. An extension line L connecting the centroids of the closed cross section is formed in a gently curved shape so as to move downward from the upper end portion of the front pillar 2 toward the rear side.
As shown in FIGS. 1 to 5, the upper half portion of the roof side outer 9 a has a groove portion 9 g extending in the front-rear direction along the extension line L. The groove 9g is formed such that the rear dimension is larger in the vertical dimension (vertical width) and the depth dimension is larger (the distance to the centroid is shorter).

Next, the lift gate 1 will be described.
As shown in FIGS. 1 to 3, the lift gate 1 is configured to be able to open and close the rear luggage compartment opening. The lift gate 1 includes a metal inner panel (not shown), a metal outer panel 11, a pair of left and right rear pillar reinforcements (not shown), a rear window glass 12, and a synthetic resin (for example, polycarbonate resin). , ABS, etc.) and the like, and is formed in a substantially curved shape in a side view.
The outer panel 11 constitutes an outer surface of a region excluding the upper end portion of the lift gate 1 and is provided with an inner lamp portion of a rear combination lamp, a rear wiper mechanism, and the like.

Next, the spoiler 20 will be described.
The spoiler 20 forms a part of the outer surface of the lift gate 1 in cooperation with the outer panel 11 so as to cover the upper end portion of the rear window glass 12.
As shown in FIGS. 1 to 3, 5, and 6, the spoiler 20 includes a substantially horizontal roof spoiler 21 and a pair of left and right substantially vertical sides that extend downward from both left and right ends of the roof spoiler 21. A spoiler 22 is provided.

As shown in FIG. 2, the roof spoiler 21 projects rearward from the rear end portion of the roof panel 10 in a side view. The roof spoiler 21 is configured such that the upper surface thereof is continuous with the upper surface of the roof panel 10 without forming an intersecting angle, and the vertical distance from the rear window glass 12 is increased toward the rear side.
The rear part of the roof spoiler 21 is equipped with a high-mount stop lamp that lights up in synchronization with the stop lamp of the rear combination lamp.

As shown in FIG. 3, the left and right ends of the roof spoiler 21 are formed in a substantially curved shape so as to extend along the extension lines of the left and right ends of the roof panel 10 in plan view. A rear side edge 21e extending in the vehicle width direction of the roof spoiler 21 is formed along the lower end of the rear window glass 12, and the central portion is disposed farthest rearward than the left and right ends.
As a result, the roof airflow flowing on the upper surface of the roof panel 10 is peeled off from the rear edge 21e of the roof spoiler 21, and lift and drag caused by the roof airflow flowing on the upper surface of the rear window glass 12 are reduced.

As shown in FIGS. 1 to 3, 5, and 6, the pair of side spoilers 22 are each configured in a substantially triangular shape in a side view.
The front side edge portion 22f and the rear side edge portion 22e of the side spoiler 22 are formed so as to correspond to (overlap) the rearward extension line of the groove portion 9g of the roof side rail 9, respectively.
The upper end portion 22a of the rear side edge portion 22e is disposed in a front position with respect to the lower end portion 22b and a front side position with respect to the rear end portion of the rear side edge portion 21e in a side view.
In the present embodiment, the lower end portion 22b and the rear end portion of the rear edge portion 21e are arranged at substantially the same longitudinal position.

The substantially straight rear side edge 22e extends upward from the middle step of the left and right ends of the rear window glass 12 and is formed so as to be substantially orthogonal to the front-rear direction.
In the present embodiment, the term “substantially orthogonal” includes an angle range of 75 ° to 90 ° in consideration of design conditions, tolerances, and the like.

Here, a setting method of the rear edge 22e will be described.
The rear edge 22e has a distance La from the reference point B to the upper end 22a and a distance Lb from the reference point B to the lower end 22b when the attachment point where the airflow that has passed through the vehicle V gathers is the reference point B. The positions of the upper end portion 22a and the lower end portion 22b are set so that.
Specifically, as shown in FIGS. 7A and 7B, the vehicle width direction center line and the outermost side in the vehicle width direction on the waist line (approximately 60% of the vehicle height). The point where the crossing angle with the line passing through the position is about 16 ° is set as the reference point B. An upper end 22a and a lower end 22b are set at positions equidistant from the reference point B.

Next, functions and effects of the rear vehicle body structure of the vehicle will be described.
In describing the actions and effects, a three-dimensional CFD (Computational Fluid Dynamics) model calculated based on CAD (Computer Aided Design) data was created and a verification experiment was performed. In this verification experiment, an example model with the same specifications as in Example 1 and a comparative example model with the same specifications as in Example 1 except that the inclination angle of the rear edge of the side spoiler is 30 ° are prepared. Each airflow was analyzed. The same configuration as that of the first embodiment will be described using the same reference numerals as those of the first embodiment.

The analysis results are shown in FIGS.
As shown in FIG. 8, in the comparative example model, the main stream of the side wall airflow (main side wall airflow) flowing over the middle stage of the left and right side panels S is respectively entangled in the roof airflow flowing over the roof panel 10.
As a result, the left and right main side wall airflows are combined with the roof airflow, and the airflow is disturbed behind the vehicle body, so-called a pair of left and right main wake vortices are generated.

The left and right side wall airflows (upper side wall airflows) flowing on the side panels S in the vicinity of the left and right roof side rails 9 are gradually separated from the vehicle body with a time difference by the rear side edges of the side spoilers, so the speed decreases. And a movement vector in the turning direction is given.
Thereby, the upper side wall airflow that has started the spiral motion is respectively engulfed by the roof airflow flowing on the roof panel 10, and a pair of left and right upper wake vortices are generated above the main wake vortex.
A negative pressure region (dead water region) where air does not move is formed between the wake vortices, and the magnitude of the negative pressure tends to increase as the wake vortex increases.

As shown in FIG. 9, in the example model, as in the comparative example model, the left and right main sidewall airflows are combined with the roof airflow to generate a pair of left and right main wake vortices.
Since the left and right upper side wall airflows flowing in the vicinity of the roof side rail 9 are simultaneously peeled from the vehicle body by the rear edge 22e of the side spoiler 22, the speed reduction is small and the spiral movement after peeling is also suppressed. Therefore, since the entrainment of the upper side wall airflow with respect to the roof airflow is suppressed, the pair of left and right upper wake vortices generated above the main wake vortex is smaller than the comparative example model.

Furthermore, since the side wall airflow flowing in the vicinity of the side rail 9 is converged by the groove 9g, the side airflow is guided to the rear edge 22e of the side spoiler 22 in a state where the decrease in the flow velocity is suppressed.
Thereby, the flow velocity of the upper side wall airflow flowing in the vicinity of the side rail 9 from the upstream side to the downstream side of the rear edge portion 22e is avoided, and the turbulence of the airflow is suppressed.
From the above, it was found that the example model has a higher wake vortex generation suppression effect than the comparative example model.

  According to this rear vehicle body structure, the spoiler 20 has the roof spoiler 21 extending left and right and the pair of left and right side spoilers 22 extending downward from the left and right ends of the roof spoiler 21 respectively. The roof airflow flowing on the upper surface of the roof panel 10 is peeled off from the rear edge 21e of the roof spoiler 21 while reducing the lift and drag force, and the side airflow flowing on the upper surface of the side panel S is separated from the rear edge of the side spoiler 22. It can be made to peel from 22e. The rear edge 22e of the side spoiler 22 extends upward from the middle step of the left and right ends of the rear window glass 12 and is formed so as to be substantially orthogonal to the longitudinal direction of the vehicle body. By causing the flowing side wall airflow to peel from the vehicle body substantially simultaneously, it is possible to suppress a decrease in the flow velocity, and to reduce the side wall airflow caught in the roof airflow.

  Since the upper end portion 22a of the rear edge portion 22e is disposed in front of the rear end portion of the roof spoiler 21, the separation timing of the side wall airflow can be made earlier than the separation timing of the roof airflow, and the roof airflow is further increased. It is possible to reduce the side wall air entrained in the wall.

It has a pair of left and right roof side rails 9 extending in the front-rear direction, and a groove 9g recessed inward in the vehicle width direction extending in the front-rear direction is formed on the outer side in the vehicle width direction of the roof side rail 9 on the rearward extension line of the groove 9g A side spoiler 22 is disposed on the side.
As a result, the side wall airflow flowing in the vicinity of the roof side rail 9 is gathered through the groove 9g, so that the side wall airflow is increased before the side airflow reaches the rear edge 22e of the side spoiler 22, and the roof airflow is increased. The speed difference between the airflow and the side wall airflow can be reduced, and the collected side wall airflow can be forcibly guided to the rear edge 22e of the side spoiler 22.

  The rear edge 22e is formed so that the distance from the predetermined reference point B to the upper end 22a set at the rear of the vehicle V is substantially equal to the distance from the reference point B to the lower end 22b. The angle of the rear edge 22e of the side spoiler 22 can be easily set.

  The rear edge 22e is formed so as to separate the roof airflow that flows on the upper surface of the roof panel 10 and the side wall airflow that flows on the upper surface of the side panel S as the vehicle travels. It can divide | segment and can suppress the influence of a wake vortex.

Next, a modified example in which the embodiment is partially changed will be described.
1] Although the example of the hatchback type passenger car has been described in the above embodiment, it may be a sedan type passenger car and can be applied regardless of the vehicle type.

2) In the above embodiment, the rear spoiler is also used as the outer panel of the lift gate. However, the rear spoiler and the outer panel of the lift gate may be separated and the rear spoiler may be set as an option.

3) In addition, those skilled in the art can implement the present invention in a form in which various modifications are added to the above-described embodiment or a combination of the above-described embodiments without departing from the spirit of the present invention. Various modifications are also included.

DESCRIPTION OF SYMBOLS 1 Lift gate 9 Roof side rail 9g Groove part 10 Roof panel 12 Rear window glass 20 Rear spoiler 21 Roof spoiler 22 Side spoiler 22e Rear edge V Vehicle B Reference point

Claims (5)

In a vehicle rear body structure having a rear window glass and a spoiler that covers an upper end side portion of the rear window glass, and a lift gate capable of opening and closing a rear luggage compartment opening,
The spoiler has a roof spoiler extending in the vehicle width direction, and a pair of left and right side spoilers extending downward from left and right ends of the roof spoiler,
The rear edge of the side spoiler is formed so as to extend upward from a middle step in the vehicle width direction end of the rear window glass and to be substantially orthogonal to the vehicle longitudinal direction. Body structure.   2. The rear body structure of the vehicle according to claim 1, wherein an upper end portion of the rear edge portion is disposed in front of a rear end portion of the roof spoiler. It has a pair of left and right roof side rails that extend in the vehicle longitudinal direction,
A groove portion recessed inward in the vehicle width direction extending in the front-rear direction is formed in the vehicle width direction outer side portion of the roof side rail,
The rear body structure of a vehicle according to claim 1 or 2, wherein the side spoiler is disposed on a rearward extension line of the groove.   2. The rear side edge portion is formed so that a distance from a predetermined reference point set to the rear of the vehicle to the upper end portion is substantially equal to a distance from the reference point to the lower end portion. The rear body structure of the vehicle according to any one of? The said rear side edge part was formed so that the roof airflow which flows through a vehicle body roof upper surface, and the side wall airflow which flows through a vehicle body side wall upper surface with driving | running | working may be formed. Rear vehicle body structure of the described vehicle.