JP2017039355A - Flow straightening structure for lower part of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flow straightening structure for a lower part of a vehicle, which aims at taking countermeasure against a heat damage as well as reducing air resistance while securing a minimum ground clearance.SOLUTION: A flow straightening structure for a lower part of a vehicle comprises: undercover 46, 47 for covering, from below, at least a part of a rear suspension device 28; an exhaust pipe 44 extending in a longitudinal direction with a lower surface side not covered with the undercovers; and insulators 60A, 60B for covering, from above in proximity, the exhaust pipe 44, arranged continuing to lower surfaces of the undercovers 46, 47. As appropriately, a part of the exhaust pipe 44 protrudes from lower surfaces of the undercovers 46, 47 and insulators 60A, 60B, and a side surface of the exhaust pipe 44 is arranged in proximately to lower surfaces of the insulators 60A, 60B.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a lower rectifying structure for an automobile provided with an under cover that covers at least a part of the under floor from below, such as a rear suspension provided under the floor and an exhaust pipe extending in the front-rear direction.

In general, an undercover is used to reduce aerodynamic resistance under the floor of an automobile.
The rear suspension of the torsion beam axle type and semi-trailing arm type that suspends the rear wheel requires a wide swinging space in the vertical direction, such as collision of underfloor wind against the suspension member, disturbance of underfloor wind, and fuel tanks, etc. A negative pressure was generated in the direction of pulling the vehicle body backward with respect to the auxiliary equipment, which caused an increase in aerodynamic resistance.

This point will be further described in detail with reference to the drawings.
FIG. 11 is a side view showing a lower rectification structure of a conventional automobile. In FIG. 11, a rear seat pan 82 and a recessed step are formed at the rear portion of the floor panel 80 via a kick-up portion 81. A rear floor 84 having a luggage compartment recess 83 is integrally formed rearward, and a rear end panel 85 extending in the vertical direction is vertically fixed to a rear end portion of the rear floor 84.

  A cross member 86 extending in the vehicle width direction is provided between the rear surface portion of the kick-up portion 81 and the lower surface of the front end portion of the rear seat pan 82, and the upper and lower portions of the rear end portion of the rear seat pan 82 are disposed in the vehicle width direction. A cross member upper 87 and a cross member lower 88 are provided, a rear cross member 89 extending in the vehicle width direction is provided below the front of the cargo compartment recess 83, and a vehicle width is provided on the front surface of the upper end of the rear end panel 85. A rear end member 90 extending in the direction is provided, and the rigidity of the lower vehicle body structure is improved by these members (elements 86 to 90) extending in the vehicle width direction.

  A fuel tank 92 is attached to the lower portion of the rear seat pan 82 using a tank band 91, and a silencer 93 is disposed below the cargo compartment recess 83, and a lower portion 93a of the silencer 93 is formed in a flat shape. It is formed to have a rectifying structure.

  A rear end under cover 95 that is integral with or separate from the rear bumper 94 is provided, while a torsion beam axle type rear suspension 96 as an example of a rear suspension is provided. The rear suspension 96 includes a torsion beam 97 that connects a pair of left and right trailing arms (not shown) in the vehicle width direction, and a spring seat 98 (specifically, a spring lower seat).

  An under cover 99 that covers the vehicle floor from below is provided, and the under cover 99 covers up to the portion immediately before the torsion beam 97 described above.

  As shown in FIG. 11, since the recess 100 is formed between the rear end portion of the fuel tank 92 and the front end portion of the silencer 93, the underfloor flowing on the lower surface of the under cover 99. The wind e8 is drawn into the recess 100, the underfloor wind e8 hits the front surface of the silencer 93, and a positive pressure (force that pushes the vehicle rearward) is generated on the front surface of the silencer 93.

Further, the underfloor wind e8 is peeled off at the rear end of the under cover 99, and negative pressure (force for pulling the vehicle rearward) is generated on the rear end surface of the fuel tank 92. Further, the underfloor wind e8 strikes the front surface of the spring seat 98 located in the above-described recess 100 between the fuel tank 92 and the silencer 93, thereby generating a positive pressure (force that pushes the vehicle rearward). A negative pressure (force that pulls the vehicle rearward) is generated on the rear surface of the spring seat 98.
The aerodynamic resistance increases due to the generation of each of these positive pressures and negative pressures.

  Therefore, in order to reduce the aerodynamic resistance, it is conceivable to cover the entire vehicle floor surface including the lower portion of the recess 100 shown in FIG. 11 with the under cover 99. However, the torsion beam 97 and the spring seat 98 of the rear suspension 96 are Since the vehicle moves up and down in accordance with the behavior of the vehicle, it is difficult to ensure a sufficient minimum ground clearance when an under cover is provided at a position where it does not interfere with the rear suspension 96.

  Furthermore, in addition to the torsion beam axle type suspension, when the majority of the floor including the exhaust pipe is covered with an undercover to reduce aerodynamic resistance, the exhaust pipe passes through the exhaust pipe and the exhaust pipe There has been a problem that the heat that is heated and released from the exhaust pipe causes heat damage such as a fuel tank and a differential such as an auxiliary machine around the exhaust pipe being overheated.

On the other hand, for example, Patent Document 1 has been proposed as a vehicle underfloor structure in which measures against heat damage are taken.
In the vehicle underfloor structure disclosed in Patent Document 1, an exhaust pipe or the like is disposed as an exhaust device extending from an engine inside a tunnel portion provided in the vehicle width direction center portion of the floor panel along the vehicle longitudinal direction. In addition, at least a part of the floor, such as the exhaust pipe, is covered from below by an under cover in order to reduce the air resistance at the lower part of the vehicle body when the vehicle is running.

  Such a vehicle underfloor structure of Patent Document 1 is provided with a latent heat storage device capable of storing heat between the tunnel portion and the exhaust pipe or between the exhaust pipe and the undercover as a countermeasure against the above-described heat damage. In order to increase the heat dissipation efficiency by increasing the surface area of the undercover, the lower surface thereof is formed in an uneven shape.

  However, the vehicle underfloor structure of Patent Document 1 has a structure in which an exhaust pipe that is heated by the passage of exhaust gas to release heat is closed from the upper and lower sides by a tunnel portion (floor panel) and an under cover. Since the problem of scolding inevitably occurs, there is a problem that the number of man-hours and the number of parts for taking various measures against heat damage as described above increase.

JP 2008-1309 A

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a lower rectifying structure for an automobile that can prevent heat damage and reduce aerodynamic resistance while ensuring a minimum ground clearance.

  The lower rectifying structure for an automobile according to the present invention includes an under cover that covers at least a part of a rear suspension device from below, an exhaust pipe whose lower surface extends in the front-rear direction without being covered by the under cover, and a lower surface of the under cover And an insulator that covers the exhaust pipe close to the top from above.

  According to the above-described configuration, the lower surface of the under cover is reduced so that the unevenness on the lower surface of the under cover and the gap between the under cover and the exhaust tube are reduced while the lower surface of the exhaust pipe is not covered with the under cover. Since the insulator that covers the exhaust pipe close to the upper side is provided, it is possible to improve the aerodynamic resistance and to secure the minimum ground height of the undercover and to suppress the heat damage.

  As an aspect of the present invention, a part of the exhaust pipe protrudes below the lower surface of the under cover and the insulator, and the side surface of the exhaust pipe is disposed close to the lower surface of the insulator.

  According to the above configuration, the gap between the insulator and the exhaust pipe can be reduced while increasing the minimum ground clearance of the undercover.

  Here, in the configuration in which the side surface of the exhaust pipe is disposed close to the lower surface of the insulator, it is preferable that the shortest distance to the exhaust pipe is close to 30 mm or less, and close to 25 mm or less. More preferred.

As an aspect of the present invention, an auxiliary machine with low heat resistance is provided under the rear floor of the vehicle body,
The exhaust pipe below the front floor of the vehicle body is covered with the under cover from below.

According to the above-described configuration, it is possible to achieve both protection of auxiliary equipment that is vulnerable to heat damage and reduction of aerodynamic resistance.
More specifically, under the rear part of the vehicle body, that is, on the downstream side of the exhaust pipe, for example, an auxiliary machine having low heat resistance such as a fuel tank, a rear differential, a motor, and a power storage device is often provided. Necessary. For this reason, the rear floor under the vehicle body is covered with the exhaust pipe close from above, and an insulator is provided so as to be continuous with the lower surface of the under cover. It is possible to reduce the aerodynamic resistance while protecting the weak auxiliary machine.
On the other hand, the aerodynamic drag can be reduced by covering the exhaust pipe from below with an under cover for the under floor of the front part of the vehicle body.
In addition, under the front floor of the vehicle body is equipped with an exhaust device such as an uneven catalyst (catalyst), so in consideration of the influence of heat radiation to the lower side (ground), under the front floor of the vehicle body, The exhaust pipe is preferably arranged above the under cover.

  Here, as the auxiliary machine having low heat resistance, for example, a rear differential gear (differential gear) provided at a lower part of a floor panel at the rear of a vehicle body of a four-wheel drive vehicle or a rear wheel drive vehicle, an electric vehicle, or a hybrid vehicle. Motors and power storage devices provided in the above.

  Further, as an aspect of the present invention, the insulator is formed with a storage portion for storing at least a part of the exhaust pipe, and a cooling lower surface portion disposed at a portion between the storage portion and the under cover. It is a thing.

  According to the above configuration, both heat conduction prevention to the undercover and reduction of aerodynamic resistance can be achieved.

  According to the present invention, measures against heat damage and reduction of aerodynamic resistance can be achieved while ensuring the minimum ground clearance.

The bottom view which shows the lower rectification | straightening structure of the motor vehicle of this invention 1 is a cross-sectional view taken along the line AA in FIG. 1 is a cross-sectional view of the main part along the line BB in FIG. 1 is a cross-sectional view of the main part along the line CC in FIG. DD sectional view taken along line D-D in FIG. Bottom view of center rear under cover Bottom view of rear center under cover Partial enlarged view of FIG. (A) is an exploded view of the fastener mounting portion of FIG. 8, (b) is a cross-sectional view when the fastener is completely mounted. Sectional view showing related structure of rear center under cover, insulator and exhaust pipe Side view of a conventional automobile lower rectification structure

An embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a bottom view showing the lower rectification structure, FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 4 is a cross-sectional view taken along the line B, FIG. 4 is a cross-sectional view taken along the line C-C in FIG. 1, FIG. 5 is a cross-sectional view taken along the line D-D in FIG. FIG. 7 is a bottom view of the rear center under cover, and FIG. 7 is a bottom view of the center rear side under cover. In the figure, arrow F indicates the front of the vehicle, and arrow R indicates the rear of the vehicle.

Prior to the description of the lower rectifying structure, the lower body structure of an automobile will be described first.
2 and 3, a rear floor 5 having a rear seat pan 3 and a luggage compartment recess 4 formed in a recessed shape at the rear of the floor panel 1 via a kick-up portion 2 rising upward. Specifically, a rear floor panel) is integrally or integrally formed rearward, and a rear end panel 6 extending in the vertical direction is vertically fixed to a rear end portion of the rear floor 5.

  A cross member 7 (so-called No. 3 cross member) extending in the vehicle width direction is provided between the back surface portion of the kick-up portion 2 and the lower surface of the front end portion of the rear seat pan 3, and the cross member 7 and each element 2 are provided. , 3 is formed with a closed cross section 8 extending in the vehicle width direction.

  A cross member upper 9 and a cross member lower 10 (so-called No. 4 cross member) extending in the vehicle width direction are joined and fixed to the upper and lower portions of the rear end portion of the rear seat pan 3. Between the member upper 9 and between the rear seat pan 3 and the cross member lower 10 are formed closed sections 11 and 12 that overlap in the vertical direction and extend in the vehicle width direction.

  Further, a rear cross member 13 (so-called No. 5 cross member) extending in the vehicle width direction is provided below the front portion of the load concave portion 4, and a vehicle width direction is provided between the rear cross member 13 and the load concave portion 4. A closed cross section 14 extending in the direction is formed.

A rear end member 15 extending in the vehicle width direction is provided on the front surface of the upper end portion of the rear end panel 6 described above, and a closed section 16 extending in the vehicle width direction is formed between the rear end member 15 and the rear end panel 6. ing.
The lower vehicle body rigidity is improved by the closed sections 8, 11, 12, 14, and 16 described above.

  As shown in FIG. 3, a fuel tank 18 as an auxiliary machine is attached to the lower portion of the rear seat pan 3 using a pair of left and right tank bands 17 and 17 (only one tank band is shown in the drawing). On the other hand, a silencer 19 is disposed below the cargo compartment recess 4, and a lower portion 19a of the silencer 19 is formed in a flat shape so as to have a rectifying structure. An insulator 20 for preventing thermal damage is disposed between the above-described cargo compartment recess 4 and the silencer 19.

Further, a rear end under cover 22 that is integral with or separate from the rear bumper 21 is provided, and the flat lower surface of the rear end under cover 22 and the flat lower portion 19a of the silencer 19 are continuous in the vehicle front-rear direction. The rear end under cover 22 forms a lower surface between the silencer 19 and the rear bumper 21.
2 and 3, reference numeral 23 denotes a bumper reinforcement that includes a bumper rain body 24 and a closing plate 25 and extends in the vehicle width direction.

  In FIG. 1, 26 is a front wheel and 27 is a rear wheel. As shown in FIGS. 1 and 5, the left and right rear wheels 27, 27 are suspended from the vehicle body by a torsion beam axle type (specifically, a coupled beam type) rear suspension 28.

  As shown in FIGS. 1 and 5, the rear suspension 28 includes a pair of left and right trailing arms 29, 29 and left and right spring seats provided at the rear portions of the pair of left and right trailing arms 29, 29, respectively. The spring lower seats 30, 30 and a torsion beam 31 (in the torsional direction) installed between the pair of left and right trailing arms 29, 29 above the left and right spring lower seats 30, 30 and in front of the vehicle in the vehicle width direction. A cross beam having elasticity).

  As shown in FIG. 5, the lower end of the rear wheel house inner 32 is joined and fixed to both ends of the rear floor 5 in the vehicle width direction, and the rear wheel house outer 32 is connected to the outer side of the rear wheel house inner 32 in the vehicle width direction. 33 is joined and fixed, and these both 32 and 33 constitute a rear wheel house.

  Further, as shown in FIG. 5, a rear side frame upper 34 and a rear side frame lower 35 are joined to both the upper and lower portions between both ends of the rear floor 5 in the vehicle width direction and the lower portion of the rear wheel house inner 32. Closed cross-sections 36 and 37 that are fixed and extend in the front-rear direction of the vehicle are formed.

  As shown in FIG. 4, a spring upper seat 38 is attached at a position facing the above-described spring lower seat 30 in the vertical direction and on the lower surface of the above-mentioned rear side frame lower 35. The spring upper seat 38 and the spring A coil spring 39 is stretched between the lower seat 30.

  As shown in FIG. 4, the above-described spring lower seat 30 is formed such that the lower surface thereof is inclined upward in the normal state. Here, the above-mentioned steady time means a time when the vehicle is traveling at a constant speed on a flat ground in a range from a state where only one driver is on board to a maximum loading capacity (or half of the maximum loading capacity).

Next, the lower rectification structure of the automobile will be described in detail.
As shown in FIG. 1, the lower part of the engine room has a vehicle floor surface covered from below by a front under cover 40 and a sub under cover 41 that are divided into a plurality of parts in the vehicle front-rear direction.
Further, the lower part of the tunnel portion 1T (see FIG. 2) extending in the vehicle front-rear direction at the center in the vehicle width direction of the floor panel 1 forming the passenger compartment floor is covered with a tunnel under cover 42 from below and the tunnel portion 1T. The lower part of the floor panel 1 located on the left and right is covered from below with a pair of left and right center front undercovers 43, 43 (see FIG. 1).

  Here, an exhaust port is provided in the cylinder head of the engine mounted in the engine room described above, and an exhaust pipe 44 is connected to an exhaust manifold connected in communication with the exhaust port. It extends toward the rear. The exhaust pipe 44 below the front floor of the vehicle body (specifically, the exhaust pipe up to the portion immediately before the kick-up portion 2 in plan view of the vehicle) is covered from below with the tunnel under cover 42 described above. In this tunnel under cover 42, a plurality of rectangular holes 42a, 42a,... Are separated from each other in the vehicle front-rear direction for the purpose of releasing heat from the exhaust pipe 44 downward, that is, outside the vehicle (FIG. 1). FIG. 2).

  The exhaust pipe 44 on the rear side of the vehicle with respect to the tunnel under cover 42 described above is stepped down with respect to the exhaust pipe 44 on the front side of the vehicle so as to avoid interference with the fuel tank 18, and the rear side thereof has an under cover (center) described later. The rear under cover 46 and the rear center under cover 47) extend below the vehicle in the front-rear direction at substantially the same height (see the exhaust pipe 44 indicated by the phantom line in FIG. 2). Thereafter, the rear end of the exhaust pipe 44 is inclined rearward and upward, and the rear end is connected to the silencer 19 described above, and the left and right sides of the silencer 19 are L-shaped in a bottom view toward the rear. Extending tail pipes 45, 45 (so-called mufflers) (see FIG. 1) are connected.

  As shown in FIGS. 1 to 4, a center rear side under cover 46 is provided as a spring seat front side cover portion that covers the front part of the rear suspension 28 from the lower side than the spring lower seat 30. The center rear side under cover 46 is at least a part of the rear suspension 28. Specifically, as shown in FIGS. 1, 4, and 5, the front side of the suspension covers the front part of the trailing arm 29 and the entire torsion beam 31 from below. Functions as a cover.

  In this embodiment, as shown in FIGS. 2, 3, and 4, the center rear side under cover 46 covers the fuel tank 18 that is an auxiliary machine having relatively low heat resistance from below.

  As shown in FIGS. 1, 5, and 6, the center rear side under cover 46 is located in the center in the vehicle width direction between the front and rear of the torsion beam 31 and the rear ends of the under covers 42 and 43. A lower surface portion 46g that covers the vehicle from below, and a lower front portion 46g of the lower surface portion 46g that is inclined downward from the left and right ends in the vehicle width direction and extends outward in the vehicle width direction, and the front portion of the trailing arm 29 of the rear suspension 28 is lowered downward. Inclined side portions 46S, 46S covering the

  Further, as shown in FIG. 1, a rear center under cover 47 is provided as a suspension center cover extending rearwardly between the spring lower seats 30 and 30 from the center portion in the vehicle width direction of the center rear side under cover 46. The rear center under cover 47 is also a central rear extension portion that extends further to the vehicle rear side than the above-described inclined side portion 46S at the center in the vehicle width direction. In this embodiment, the rear center under cover 47 described above is formed in a trapezoidal shape as viewed from the bottom, as shown in FIGS.

As shown in FIGS. 1, 3, and 4, a rear side under cover 48 is provided as a spring seat rear cover portion that covers the lower floor behind the above-described spring lower seat 30 from below. As shown in the bottom view in FIG. 1, the rear side under cover 48 is located behind the trailing arm 29 and is divided into two parts on the left and right.
Each of the undercovers 40, 41, 42, 43, 46, 47, 48 described above is made of synthetic resin or non-woven fabric.

  As shown in FIGS. 2 and 5, under the rear floor of the vehicle, the exhaust pipe 44 includes a center rear under cover 46 and a rear center under cover 47, and approximately half of the upper surface side of the under covers 46 and 47. It overlaps with the lower part, and the lower surface side substantially half is arrange | positioned by the height which protrudes below rather than the lower surfaces 46c and 47c of the undercovers 46 and 47. As shown in FIG.

  The exhaust pipe 44 is not covered from the lower side by the center rear side under cover 46, the rear center under cover 47, and the insulator 60, and the lower surface is exposed to the outside.

  As shown in FIG. 6, the center rear side under cover 46 is composed of at least two members, ie, flat center rear side under cover constituting members 46A and 46A arranged on the left and right sides of the exhaust pipe 44.

  On the other hand, as shown in FIG. 7, the above-described rear center under cover 47 is disposed on the left and right sides with respect to the exhaust pipe 44 and an undercover side storage section 47c that is convex upward to store the upper surface portion of the exhaust pipe 44. The plate-shaped rear center under cover lower surfaces 47g and 47g are integrally formed.

  In the present embodiment, as shown in FIG. 1, the above-described under covers (center rear side under cover 46 and rear center under cover 47) are insulators 60A and 60B that cover the exhaust pipe 44 from above. Is attached. As shown in FIGS. 8 and 10, such insulators 60 </ b> A and 60 </ b> B are provided on the center rear side under cover 46 side and the rear center under cover 47 side and have substantially the same cross-sectional shape. , Both are formed of aluminum or aluminum alloy.

  Specifically, the above-described insulator 60A provided on the center rear side under cover 46 side has an upwardly convex storage portion 60a (this is stored in the upper surface portion of the exhaust pipe 44 as shown in FIGS. 5 and 8). In the embodiment, the storage section 60 a) having a semicircular shape with an upward convex cross section, and flat plate-like cooling lower surface sections 60 b and 60 b located between the lower portion of the storage section 60 a and the center rear side undercover 46. Are integrally formed.

  Further, in the present embodiment, the storage section 60a having a semicircular cross section is disposed so as to be substantially concentric with the exhaust pipe 44. As described above, the upper semicircle in cross section of the exhaust pipe 44 is disposed. The portion is covered by the storage portion 60a of the insulator 60A, and the lower semicircular portion in the sectional view of the exhaust pipe 44 is not covered by the storage portion 60a and is disposed so as to protrude below the lower surface of the insulator 60. .

  In such an arrangement of the exhaust pipe 44 and the storage section 60a, the side face of the exhaust pipe 44 is arranged so as to be close to the inner peripheral surface of the insulator 60A, as indicated by a gap d1 in FIG.

  In particular, the exhaust pipe 44 and the storage portion 60a are arranged on the left and right sides of the exhaust pipe 44, respectively, as an outer end portion 44t in the vehicle width direction of the exhaust pipe 44 and an inner end portion in the vehicle width direction of the cooling lower surface portion 60b of the insulator 60. 60t is arranged so as to be closest to each other (see FIG. 8).

  Specifically, as shown in FIG. 8, the exhaust pipe 44 and the storage portion 60 a are arranged on the left and right sides of the exhaust pipe 44, inside the outer end portion 44 t of the exhaust pipe 44 and the cooling lower surface portion 60 b of the insulator 60. It is preferable that the gap d1 with the end 60t is close to 30 mm or less, and it is more preferable that the gap d1 is close to 25 mm or less.

  Here, although not shown, the exhaust pipe 44 is supported by a hanger provided on a floor panel 80, a frame or the like of the vehicle body through an elastic member such as rubber or a spring so as to be able to swing a predetermined amount. Transmission of vibration of the tube 44 itself to the vehicle body is reduced.

  Therefore, the gap d1 in the vehicle width direction between the exhaust pipe 44 and the storage portion 60a is made closest and smaller than the vertical gap, and the exhaust pipe 44 is easy to move in the vertical direction and difficult to move in the vehicle width direction. By setting at least one of the position of the hanger or the elastic characteristic of the elastic member, it is possible to secure a rocking space sufficient for suppressing vibration transmission and to reduce the gap d1 in the vehicle width direction between the exhaust pipe 44 and the storage portion 60a. You may make it balance aerodynamic resistance reduction.

  Further, as shown in FIG. 8, the cooling lower surface portions 60b and 60b of the insulator 60 arranged on the left and right sides with respect to the exhaust pipe 44 are center rear side under cover constituting members 46A and 46A corresponding to the left and right sides, respectively. The fastener 52 is attached so as to be continuous with the lower surface 46g of the steel plate. That is, the left and right center rear undercover constituent members 46A and 46A are attached so as to be connected via the insulator 60, whereby the left and right center rear undercover constituent members 46A and 46A divided into two members are centered. The rear under cover 46 is integrated (see FIG. 8).

  As shown in FIG. 9, the fastener 52 includes a fastener main body 52A having a locking piece 52c having a locking claw 52a at the distal end and a flange 52b at the proximal end, a shaft portion 52d, and a flange shaft 52e. The lock pin 52B is integrally formed.

  As shown in FIG. 9A, the fastener main body 52A is set in advance in the mounting holes 53 for attaching the fasteners 52 formed in the respective elements 60A, 46, and the holes of the fastener main body 52A are viewed from the direction of the arrow in FIG. When the lock pin 52B is inserted into the portion, as shown in FIG. 9 (b), the locking piece 52c increases in diameter, and the both 60A and 46 are clamped and fixed between the locking claw 52a and the flange 52b. is there.

  Subsequently, the related structure of the rear center under cover 47, the insulator 60B, and the exhaust pipe 44 will be described with reference to FIG. 10, but is the same as the related structure of the center rear side under cover 46, the insulator 60A, and the exhaust pipe 44 described above. The description of the structure is omitted.

  FIG. 10 is a cross-sectional view showing a related structure of the rear center under cover 47, the insulator 60B, and the exhaust pipe 44.

  With respect to the rear center under cover 47, the cooling lower surface portions 60b and 60b of the insulator 60 are attached to the exhaust pipe 44 so as to be continuous with the lower surface 47g of the rear center under cover lower surface portions 47f and 47f. .

  Further, the rear center under cover 47 is provided with an under cover side storage portion 47c, and the lower surface (the surface on the side having the exhaust pipe 44) of the under cover side storage portion 47c is the upper surface of the storage portion 60a of the insulator 60. It is attached in a state opposite to (in this embodiment, a polymerized state).

  As shown in FIG. 4, below the spring lower seat 30, the opening 49 that is not covered with the under cover, that is, any of the center rear side under cover 46, the rear center under cover 47, and the rear side under cover 48, is provided. An opening 49 that is not covered by the under cover is formed, and the opening 49 allows the spring lower seat 30 to move up and down.

  As shown in the bottom view in FIG. 1, the rear side under cover 48 and the rear wheel 27 are covered with under covers 46 and 47 at the outside of the silencer 19 in the vehicle width direction from the vehicle width direction end. A second opening 62 that is not provided is provided, and the tail pipe 45 described above is disposed at a position corresponding to the second opening 62.

  As described above, the lower rectification structure of the automobile according to the present embodiment described above is an under cover that covers at least a part of a rear suspension 28 as a rear suspension device from below as shown in FIGS. 1, 5, 8, and 10. The rear rear under cover 46 and the rear center under cover 47, the exhaust pipe 44 whose lower surface is not covered by the under covers 46, 47 and extending in the front-rear direction, the lower surfaces 46g of the under covers 46, 47, Insulators 60A and 60B that are continuous with 47g and cover the exhaust pipe 44 close to each other from above are provided.

  According to the above configuration, the minimum ground height of the under covers 46 and 47 (center rear side under cover 46 and rear center under cover 47) and thermal damage can be suppressed while improving the aerodynamic resistance.

  Specifically, from the viewpoint of reducing aerodynamic resistance, it is preferable to cover most of the under floor including the rear suspension 28 of the torsion beam axle type and the exhaust pipe 44 with the undercovers 46 and 47.

  However, when most of the floor is covered with the undercovers 46 and 47, it is difficult to secure the minimum ground clearance, and the exhaust heat released from the exhaust pipe 44 and the like tends to spread around the exhaust pipe 44 and the like. Therefore, it is necessary to take measures against heat damage to protect the auxiliary equipment such as the fuel tank 18 and the differential (not shown) from the exhaust heat.

  That is, the conventional lower rectification structure of an automobile cannot solve all of the problems of measures against heat damage and aerodynamic resistance while ensuring a minimum ground clearance.

  On the other hand, according to the above configuration, as shown in FIGS. 8 and 10, the lower surface side of the exhaust pipe 44 is not covered with the undercovers 46 and 47 and is arranged directly facing the ground, while the undercover 46 is disposed. , 47 are continuous with the lower surfaces 46g, 47g of the undercovers 46, 47 and the exhaust pipe 44 from above so that the unevenness of the lower surfaces 46g, 47g of the undercovers 46, 47g and the gap between the undercovers 46, 47 and the exhaust pipe 44 are reduced. Since the insulators 60A and 60B that cover each other are provided, respectively, the minimum ground height of the undercovers 46 and 47 and thermal damage can be suppressed while improving the aerodynamic resistance.

  Further, by providing the insulators 60A and 60B so as to be continuous with the lower surfaces 46g and 47g of the undercovers 46 and 47 and close to the exhaust pipe 44, the vehicle body floor is just before the undercover 46 and 47 reaches the exhaust pipe 44. As a result, the disturbance of the underfloor wind e1 can be suppressed.

  In particular, the undercovers 46 and 47 are made of resin, whereas the insulators 60A and 60B are made of aluminum or aluminum alloy having higher heat resistance, so that the lower surfaces of the insulators 60A and 60B, that is, The cooling lower surface portions 60b and 60b can be brought closer to the exhaust pipe 44. Furthermore, since the cooling lower surfaces 60b and 60b of the insulators 60A and 60B are provided between the undercovers 46 and 47 and the exhaust pipe 44, the undercovers 46 and 47 can be arranged without being close to the exhaust pipe 44. . Therefore, the undercovers 46 and 47 are not limited to materials having heat resistance that can withstand exhaust heat, but can be formed of, for example, resin or non-woven fabric. As a result, the weight of the vehicle body and the material cost can be reduced. Can be achieved.

  In addition, the exhaust pipe 44 is disposed in the front-rear direction without being covered by the undercovers 46 and 47 so that the lower surface thereof directly faces the ground side, and further, the insulator 60A that covers the exhaust pipe 44 close from above is provided. 60B, in particular, the storage portion 60a is provided, so that a large gap can be ensured between the exhaust pipe 44 and the auxiliary machine that is to be protected from heat, such as the fuel tank 18, and the auxiliary machine such as the fuel tank 18 and the insulator 60A, While the air layer between 60B can be increased and the air flow can be improved, the cooling efficiency for heat radiation from the exhaust pipe 44 can be increased.

  As an aspect of the present invention, a part of the exhaust pipe 44 protrudes below the lower surfaces of the insulators 60A and 60B, that is, the lower surface portions 60b and 60b for cooling and the undercovers 46 and 47, and the side surface of the exhaust pipe 44 is The insulators 60A and 60B are disposed close to the lower surface (see FIGS. 2, 5, 8, and 10).

  According to the above configuration, the minimum ground clearance of the undercovers 46 and 47 can be increased as compared with the case where the exhaust pipe 44 is covered with the undercovers 46 and 47 from below.

  In addition, according to the above configuration, the exhaust pipe 44 is disposed without protruding downward from the lower surfaces of the insulators 60A and 60B depending on the downward projection amount of the exhaust pipe 44 with respect to the lower surfaces of the under covers 46 and 47 and the insulators 60A and 60B. Compared to the conventional case, the lower surfaces of the insulators 60 </ b> A and 60 </ b> B can be brought closer to the side surface of the exhaust pipe 44.

Specifically, for example, in the case of a conventional arrangement structure in which the exhaust pipe 44 is arranged without protruding downward from the lower surfaces of the insulators 60A and 60B, such as the exhaust pipe 440 indicated by the phantom line in FIG. The gap (d2) between the lower surface of 60B (the lower surface portions 60b and 60b for cooling) and the exhaust pipe 440 increases, and the wind flowing under the floor may become turbulent.
On the other hand, as shown in FIGS. 8 and 10, as in the present embodiment, a part of the exhaust pipe 44 protrudes below the lower surfaces of the undercovers 46 and 47 and the insulators 60A and 60B. By arranging in this manner, a gap d1 (see FIGS. 8 and 10) between the inner end 60t in the vehicle width direction of the lower surface portions 60b and 60b for cooling and the side surface (outer end 44t in the vehicle width direction) of the exhaust pipe 44 is formed. Since it can reduce, disturbance of underfloor wind e1 can be controlled.

  Moreover, as described above, the exhaust pipe 44 is not covered from the lower side by the undercovers 46 and 47 and the insulators 60A and 60B, but a part thereof is below the lower surfaces of the undercovers 46 and 47 and the insulators 60A and 60B. Since it arrange | positions so that it may protrude, the influence of a heat damage can be reduced.

  As an aspect of the present invention, an auxiliary machine such as a fuel tank 18 having low heat resistance is provided below the rear floor of the vehicle body, and the exhaust pipe 44 below the front floor of the vehicle body is the center rear undercover 46 of the undercovers 46 and 47. And covered from below (see FIGS. 2 to 4).

According to the above configuration, it is possible to achieve both protection of an auxiliary machine that is vulnerable to heat damage and reduction of aerodynamic resistance.
Specifically, the fuel tank 18 and the auxiliary equipment having low heat resistance such as a rear differential, a motor, and a power storage device are provided below the rear floor of the vehicle body, that is, downstream of the exhaust pipe 44, although not shown. Heat damage measures are required.

  For this reason, a part of the exhaust pipe 44 projects below the lower surfaces of the undercovers 46 and 47 and the insulators 60A and 60B below the rear floor of the vehicle body, and the side surfaces of the exhaust pipe 44 are extended to the undercovers 46 and 47. By arranging the insulators close to the bottom surfaces of the insulators 60A and 60B that are continuous with the bottom surfaces 46g and 47g, it is possible to achieve both protection of an auxiliary machine that is vulnerable to heat damage and reduction of aerodynamic resistance.

  On the other hand, since the exhaust pipe 44 under the front floor of the vehicle body is covered almost completely from below by the undercovers 46 and 47, aerodynamic resistance can be greatly reduced. In addition, since the exhaust system such as a catalyst (catalyst) (not shown) having an uneven surface is provided under the front floor of the vehicle body, it is necessary to secure a minimum ground clearance and to lower (ground) From the viewpoint of thermal radiation, the exhaust pipe 44 is preferably disposed above the undercovers 46 and 47 below the front floor of the vehicle body. And since the arrangement | positioning height of the exhaust pipe 44 is set higher in the direction under the vehicle body front floor under the vehicle body front floor, it is possible to ensure the minimum ground clearance even under the vehicle body front floor.

  Further, as an aspect of the present invention, the insulators 60A and 60B include a storage portion 60a that opens downwardly and stores at least a part of the exhaust pipe 44, and a space between the storage portion 60a and the undercovers 46 and 47. The cooling lower surface portions 60b and 60b are formed in the region (see FIGS. 8 and 10).

  According to the above configuration, the undercovers 46 and 47 do not require a complicated configuration for heat damage countermeasures, such as providing a heat storage material or a heat insulating material around the exhaust pipe 44, or complicated installation work for the heat damage countermeasure means. It is possible to achieve both prevention of heat conduction and reduction of aerodynamic resistance.

  More specifically, the cooling lower surface portions 60b, 60b are interposed between the exhaust pipe 44 and the under covers 46, 47 in the vehicle width direction, so that the space between the exhaust pipe 44 and the under covers 46, 47 is firmly secured. The bottom of the floor can be formed by the lower surface portions 60b and 60b for cooling while preventing heat damage due to the exhaust heat released from the exhaust pipe 44. Can dissipate heat.

  Accordingly, heat conduction to the under covers 46 and 47 can be prevented.

Further, in the insulators 60A and 60B, the clearances between the exhaust pipe 44 and the under covers 46 and 47 are provided by disposing the cooling lower surface portions 60b and 60b between the storage portion 60a and the under covers 46 and 47. d1 can be minimized. Moreover, since the cooling lower surface portions 60b and 60b of the flat insulators 60A and 60B continuous with the lower surfaces 46g and 47g of the undercovers 46 and 47 form a rectifying surface, aerodynamic resistance can be suppressed.
Therefore, it is possible to reduce the aerodynamic resistance under the vehicle floor.

  Further, since the insulators 60A, 60B are provided so as to be continuous with the lower surfaces 46g, 47g of the under covers 46, 47, the lower surfaces 46g, 47g of the under covers 46, 47 and the cooling lower surface portions 60b, 60b of the insulators 60A, 60B As shown in FIGS. 8 and 10, since they can be connected so as to overlap each other in a surface contact state, the connection becomes easy, and the insulators 60A and 60B can be easily attached to the under covers 46 and 47.

  Conventionally, when a torsion beam type (especially a coupled beam type) rear suspension 28 is employed, it is necessary to secure a vertical stroke of the torsion beam 31 (cross beam). However, the exhaust pipe 44 was not passed through the lower side.

  On the other hand, when the exhaust pipe 44 is disposed above the torsion beam 31 and the torsion beam 31 is covered with the center rear side under cover 46 from below, there is a problem that the minimum ground clearance is lowered.

  On the other hand, as shown in FIG. 5, the lower rectification structure of the automobile according to the present embodiment includes a torsion beam 31 and an exhaust pipe 44 below the torsion beam 31, and a center rear undercover 46, An undercover layout in which only the torsion beam 31 is covered from below by the insulator 60A is realized, and the insulator 60A is connected to the rear center undercover 47 in a continuous manner to ensure a minimum ground clearance, while reducing aerodynamic resistance and heat damage. Countermeasures can be realized at a higher level.

In the correspondence between the configuration of the present invention and the above-described embodiment,
The rear suspension of the present invention corresponds to the rear suspension device 28 of the embodiment, and similarly,
The under cover corresponds to the center rear side under cover 46 and the rear center under cover 47,
The lower surface of the under cover corresponds to the lower surface 46g of the center rear side under cover and the lower surface 47g of the rear center under cover,
Although the auxiliary machine corresponds to the fuel tank 18, the present invention is not limited to the configuration of the above-described embodiment.

  As described above, the present invention is useful for a lower rectification structure of an automobile provided with an under cover that covers at least a part of the vehicle floor underneath, such as a rear suspension provided under the floor, from below.

18 ... Fuel tank 28 ... Rear suspension 44 ... Exhaust pipe 46 ... Center rear side under cover 47 ... Rear center under cover 46g ... Center rear side under cover lower surface 47g ... Rear center under cover lower surfaces 60A, 60B ... Insulator 60a ... Storage Part 60b ... lower surface part for cooling

Claims (4)

An undercover covering at least a part of the rear suspension device from below;
An exhaust pipe whose bottom surface extends in the front-rear direction without being covered by the under cover;
A lower rectification structure for an automobile provided with an insulator that is continuous with a lower surface of the under cover and covers the exhaust pipe close from above. 2. The lower rectifying structure for an automobile according to claim 1, wherein a part of the exhaust pipe projects below the lower surface of the under cover and the insulator, and a side surface of the exhaust pipe is disposed close to the lower surface of the insulator. . An auxiliary machine with low heat resistance is installed under the rear floor of the vehicle body,
The lower rectification structure for an automobile according to claim 1 or 2, wherein the exhaust pipe under the front floor of the vehicle body is covered with the under cover from below. 4. The insulator according to claim 1, wherein the insulator includes a storage portion that stores at least a part of the exhaust pipe, and a cooling lower surface portion that is disposed at a portion between the storage portion and the under cover. The lower rectifying structure for an automobile according to any one of the preceding claims.

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