JP5390930B2 - Body front structure - Google Patents

Description

  The present invention relates to a front structure of a vehicle body such as an automobile, and more particularly to a structure having a cradle connected to a lower part of a main frame and mounted with various parts such as an engine and a suspension.

As a front part structure of a vehicle body such as an automobile, a main frame extending forward from the compartment front partition along the left and right side parts of the engine room, and a cross beam-like cross member connecting the lower parts of the left and right main frames There is a known configuration in which various components such as an engine mount, a steering gear box, and a vehicle body side support portion of a suspension arm are mounted on the cross member.
As a conventional technique related to such a vehicle body front structure, for example, Patent Document 1 describes that an engine or the like is mounted on a cross member that is reinforced by forming closed cross-sections in front and rear of a plate-like main body. .

JP 2008-284894 A

  In order to improve the running performance of the vehicle, it is desired to lower the center of gravity of the vehicle by mounting a power unit such as an engine at a lower position. In order to lower the mounting position of the engine and secure the minimum ground clearance of the vehicle, it is necessary to form a thin engine mounting member such as a cross member. For example, in the technique disclosed in Patent Document 1, the cross member is simply thinned. When formed, it is difficult to ensure rigidity.

In recent years, it has also been proposed to install a frame-like cradle at the bottom of the main frame and mount the engine etc. on this cradle, but even with a structure using a cradle, in order to lower the engine mounting position The transverse member of the cradle needs to be thin, and it is difficult to ensure rigidity.
The subject of this invention is providing the vehicle body front part structure which can ensure the rigidity of a cradle even when a through member is made thin.

The present invention solves the above-described problems by the following means.
The invention according to claim 1 is a vehicle body front part structure including a main frame that protrudes forward from the front partition of the vehicle compartment and is disposed on each of the left and right sides of the engine room, and a cradle attached to a lower portion of the main frame. The cradle extends substantially along the longitudinal direction of the vehicle and is spaced apart in the vehicle width direction, and a pair of longitudinal members respectively coupled to the lower portions of the left and right main frames, and substantially in the vehicle width direction. A front lateral member extending along the longitudinal member and extending along the vehicle width direction, and extending substantially along the vehicle width direction and extending along the longitudinal member, spaced from the rear side of the front lateral member A rear lateral member disposed at a distance from each other, and an intermediate portion of the front lateral member and an intermediate portion of the rear lateral member that extend substantially along the vehicle longitudinal direction and are spaced apart from each other in the vehicle width direction. And And a pair of connecting member for forming the intermediate portion of the front Yokodori members and the rear Yokodori member is curved to form such raised to the post-processing exhaust gas of the engine between the left and right of the connecting member A vehicle body front part structure in which at least a part of a catalytic converter is disposed .

The invention of claim 2 includes a suspension arm swingably attached to the cradle, wherein at least a part of the attachment portion of the suspension arm is in the vicinity of a connection portion between the longitudinal member and the front lateral member, Or it is arrange | positioned in the connection part vicinity of the said longitudinal member and the said rear lateral member, The vehicle body front part structure of Claim 1 characterized by the above-mentioned.
The invention according to claim 3 includes an engine mount provided on the front lateral member and mounted with an engine, and a steering gear box attached to the rear lateral member. 2 is a vehicle body front structure.
The invention according to claim 4 is the vehicle body front part structure according to claim 3, characterized in that the engine mount is arranged in the vicinity of a joint portion between the front lateral member and the connecting member.
The invention of claim 5 is characterized in that the connecting member is formed by continuously expanding the cross-sectional shape in the vicinity of the connecting portion between the front lateral member and the rear lateral member with respect to the intermediate portion. The vehicle body front part structure according to any one of claims 1 to 4 .

According to the present invention, the following effects can be obtained.
(1) By connecting the left and right longitudinal members with the front lateral member and the rear lateral member, and connecting the front and rear lateral members with a coupling member, the load input to one lateral member is Can be distributed to the horizontal members and efficiently transmitted to the left and right vertical members. For this reason, it is easy to ensure rigidity even when the cross-section of the cross member is reduced in the height direction in order to lower the mounting position of the engine or the like. As a result, it is possible to reduce the center of gravity of the vehicle and improve the running performance. For example, when each transverse member has a curved shape in order to prevent interference with other parts such as an exhaust pipe, the member is stretched or deformed by a lateral tensile load, or the member is deformed by a compressive load. There is a concern that bending deformation may occur, but even in such a case, deformation of the member can be suppressed by bearing the load between the front and rear members.
(2) By disposing at least a part of the suspension arm attachment portion in the vicinity of the connecting portion between the longitudinal member and either the front or rear transverse member, the lateral input acting on the longitudinal member from the suspension arm is reversed. Can be transmitted to the longitudinal member on the side, the rigidity of the attachment portion of the suspension arm can be improved, and the running performance of the vehicle can be further improved.
(3) An engine mount is provided on the front lateral member, and a steering gear box is attached to the rear lateral member, so that the load on the front and rear lateral members is distributed and a light weight structure is achieved. Thus, rigidity can be secured by transmitting the load between the front and rear transverse members.
(4) By disposing the engine mount in the vicinity of the joint between the front lateral member and the connecting member, the load input from the engine mount to the front lateral member can be efficiently input to the connecting member.
(5) The load can be efficiently transmitted by forming the cross-sectional shape in the vicinity of the connecting portion of the connecting member with each lateral member continuously enlarged with respect to the intermediate portion.
(6) By disposing at least a part of the catalytic converter for post-processing engine exhaust gas in the interval between the left and right connecting members, the mounting height of the catalytic converter can be increased while effectively utilizing the dead space to reduce the minimum ground clearance. It can be secured.

It is a perspective view of the Example of the vehicle body front part structure to which this invention is applied. It is a perspective view of the vehicle body main body and the cradle in the vehicle body front part structure of the embodiment. It is a perspective view of the vehicle body in the vehicle body front part structure of the embodiment. It is a perspective view of the cradle in the vehicle body front part structure of an Example. It is a perspective view which shows the state which mounted the exhaust pipe etc. in the cradle of FIG. It is a top view of the vehicle body front part structure of an Example. FIG. 7A is a schematic cross-sectional view of a vehicle body front portion structure of an embodiment, and FIGS. 7A, 7B, and 7C are respectively aa portion, bb portion, and c of FIG. -C part arrow sectional drawing.

  The present invention provides a vehicle body front structure capable of ensuring the rigidity of the cradle even when the transverse member is thin, and connects the pair of left and right longitudinal members with a pair of front and rear transverse members, Furthermore, the problem was solved by connecting the front and rear transverse members with a pair of left and right connecting members.

Embodiments of a vehicle body front structure to which the present invention is applied will be described below. The vehicle body front structure of the embodiment is applied to an automobile such as a front engine passenger car, for example.
The vehicle body front structure includes a vehicle body 100 and a cradle 200, and further, an engine mount 310, an exhaust pipe 320, a steering gear box 330, a suspension arm 340, and the like are attached.

The vehicle body 100 is, for example, a white body (unmounted vehicle body) having a steel plate monocoque cabin, and is formed by assembling mainly pressed members of steel plates and joining them by spot welding, laser welding, or the like. Yes.
As shown in FIG. 1 and the like, the vehicle body 100 includes a toe board 110, a floor panel 120, a main frame 130, an upper frame 140, a suspension support 150, a bumper beam 160, a radiator upper support 170, a radiator lower support 180, and the like. .

The toe board 110 is a partition that is provided in front of a cabin (cabin) (not shown) and divides the cabin and an engine room in front of the cabin.
The floor panel 120 is a portion constituting the floor surface of the passenger compartment, and extends from the lower end portion of the toe board 110 to the vehicle rear side.
A floor tunnel 121 extending in the vehicle front-rear direction is formed at the center of the floor panel 120 in the vehicle width direction. The floor tunnel 121 is formed so as to protrude upward, and a transmission, a propeller shaft, a part of an exhaust pipe, and the like are accommodated in the interior (below the floor).

  The main frame 130 is a structural member that is provided on the left and right sides of the engine room and extends substantially along the longitudinal direction of the vehicle. The main frame 130 is a beam-like member with a closed cross section having a substantially rectangular cross section. Note that in this specification and the like, the transverse section refers to a section obtained by cutting a beam-like member along a plane orthogonal to the longitudinal direction thereof. The front half of the main frame 130 is disposed so as to protrude from the lower part of the toe board 110 toward the vehicle front side. The rear half of the main frame 130 is curved so that the shape seen from the vehicle width direction is S-shaped, and is arranged from the lower part of the toe board 110 along the lower surface of the floor panel 120, and is joined thereto by welding or the like. Yes.

The main frame 130 includes a front bracket 131 and a rear bracket 132 to which the cradle 200 is coupled. The front bracket 131 and the rear bracket 132 are provided at the front end portion and the middle portion of the main frame 130, respectively, and are formed to protrude downward from the lower surface portion of the main frame 130. The front bracket 131 and the rear bracket 132 have closed cross-sections that are cut in a horizontal plane and are substantially rectangular.
In addition, an escape recess that prevents interference with the front wheels at the time of large steering angle turning is formed in the side surface portion on the outer side in the vehicle width direction in the intermediate portion of the main frame 130 as necessary.

The upper frame 140 is a member that extends to the front side of the vehicle from a portion of the toe board 110 that is above the position where the toe board 110 is coupled to the main frame 130 and outside in the vehicle width direction. The upper frame 140 is disposed along both side portions of the hood (not shown) from the base portion of the A pillar (not shown). The upper frame 140 is a beam-like member having a closed cross section having a substantially rectangular cross section.
A region from the middle portion to the rear end portion of the upper frame 140 is disposed substantially along the vehicle front-rear direction. This region is arranged above the main frame 130 and outside in the vehicle width direction.
The region in the vicinity of the front end portion of the upper frame 140 is arranged to be inclined with respect to the vehicle front-rear direction so that the front end portion is lowered and offset inward in the vehicle width direction.

As shown in FIG. 7C, the side surface portion on the inner side in the vehicle width direction at the front end portion of the upper frame 140 is coupled to the side surface portion on the outer side in the vehicle width direction of the main frame 130.
Moreover, as shown in FIG. 1 etc., the front bracket 131 mentioned above is arrange | positioned just before this coupling | bond part.

  The suspension support 150 includes a bracket that supports the upper end of a strut of a McPherson strut suspension that is a front wheel suspension. As shown in FIG. 7A and the like, the suspension support part 150 is disposed between the main frame 130 and the upper frame 140. The suspension support 150 is formed with a closed cross section (not shown) that connects the main frame 130 and the upper frame 140.

The bumper beam 160 is a transverse beam-like member attached to the front end portion of the main frame 130 and extending substantially along the vehicle width direction, and is disposed inside a bumper face (not shown).
The radiator upper support 170 and the radiator lower support 180 are members that support an upper end portion and a lower end portion of a condenser core (not shown) and a condenser core for an air conditioner.
The radiator upper support 170 is provided between the left and right upper frames 140.
The radiator lower support 180 is provided between the lower ends of the front brackets 131 of the left and right main frames 130.

The cradle 200 is a structural member (subframe) that is attached to the lower side of the main frame 130 of the vehicle body 100 and on which various components are mounted.
As shown in FIG. 4 and the like, the cradle 200 includes a longitudinal member 210, a front lateral member 220, a rear lateral member 230, a connecting member 240, a front end member 250, and a lower member 260 (not shown in FIG. 4). 1) etc.).

The longitudinal members 210 are members that are respectively provided below the left and right main frames 130 and extend substantially along the vehicle longitudinal direction. The cross-sectional shape of the longitudinal member 210 is a substantially rectangular closed cross section. The longitudinal member 210 includes a bracket 211, a front arm attachment portion 212, a rear arm attachment portion 213, and the like.
The bracket 211 is formed so as to protrude upward from an intermediate portion of the longitudinal member 210. The lower end of the rear bracket 132 of the main frame 130 is connected to the upper end of the bracket 211.
The front arm attachment portion 212 and the rear arm attachment portion 213 are provided on the side surface portion of the longitudinal member 210 on the outer side in the vehicle width direction so as to be separated in the front-rear direction. A front bush 341 and a rear bush 342 of the suspension arm 340 are attached to the front arm attachment portion 212 and the rear arm attachment portion 213, respectively.
As shown in FIG. 4 and the like, the front arm attachment portion 212 is disposed in the middle portion of the longitudinal member 210 (near the joint portion of the main frame 130 with the front bracket 131), and the rear arm attachment portion 213 is disposed in the longitudinal member 210. It is arrange | positioned in the rear-end part vicinity.
Further, the rear region of the longitudinal member 210 is raised so that the rear end portion is higher than the other portions.

The front lateral member 220 is a member that extends substantially along the vehicle width direction and connects the left and right longitudinal members 210. The front cross member 220 has a substantially rectangular closed cross section. A joint portion between the front lateral member 220 and the longitudinal member 210 is disposed in the vicinity of the bracket 211.
As a result of such a configuration, the upper frame 140 and the main frame 130 are connected by the suspension support portion 150, and the main frame 130 and the longitudinal member 210 of the cradle are connected to each other by the rear bracket 132 and the bracket 211 in the lower part. Further, in the vicinity thereof, the left and right longitudinal members 210 can be coupled by the front lateral member 220, and in the vicinity of the middle portion of the main frame 130, a continuous substantially U-shape when viewed from the front of the vehicle. A strong stiffening structure is formed.

The rear lateral member 230 is a member that extends substantially along the vehicle width direction and connects the left and right longitudinal members 210. The rear cross member 230 has a substantially rectangular closed cross section. The rear lateral members 230 are disposed on the rear side of the front lateral members 220 at intervals in the front-rear direction. The joint portion of the rear lateral member 230 with the longitudinal member 210 is disposed in the vicinity of the rear arm attachment portion 213.
As for the cross-sectional shapes of the front lateral member 220 and the rear lateral member 230, the vicinity of the junction with the longitudinal member 210 is enlarged with respect to the intermediate portion.
Further, the front lateral member 220 and the rear lateral member 230 are formed to be curved so that the central portion is lifted in order to pass the exhaust pipe 320 below the central portion.

  The connecting member 240 is a member that extends substantially along the front-rear direction of the vehicle and connects between the intermediate portion of the front lateral member 220 and the intermediate portion of the rear lateral member 230. The cross-sectional shape of the connecting member is a substantially rectangular closed cross section. A pair of connecting members 240 are provided, for example, separated in the vehicle width direction. As for the cross-sectional shape of the connecting member 240, the vicinity of the joint portion between the front lateral member 220 and the rear lateral member 230 is enlarged with respect to the intermediate portion. The expansion of the closed cross section is performed gradually and continuously, and as a result, both end portions of the connecting member 240 are formed in a tapered shape.

  The front end member 250 is a cross beam-like member that connects the front end portions of the left and right longitudinal members 210.

A lower member 260 shown in FIG. 1 and the like is a vertical beam-like member provided between the lower surface portion of the rear portion of the longitudinal member 210 and the lower surface portion of the main frame 130 disposed along the lower surface of the floor panel 120. is there. A gap is formed between the lower surface of the rear end of the longitudinal member 210 and the upper surface of the lower member 260, and both ends of the steering gear box 330 are passed through this gap.
The longitudinal member 210, the front lateral member 220, the rear lateral member 230, the connecting member 240, and the front end member 250 are joined to each other by welding or the like, and the lower member 260 is formed separately. And are fastened by bolts and nuts or the like.

The engine mount 310 supports an engine (not shown) through rubber having vibration isolation properties. For example, a pair of left and right engine mounts 310 are provided, and are fixed in the vicinity of the joint portion with the connecting member 240 on the upper surface portion of the front lateral member 220 of the cradle 200.
In this embodiment, the engine is, for example, a horizontally opposed engine with a lower exhaust mounted vertically.

The exhaust pipe 320 discharges exhaust gas discharged from the exhaust port below the engine from the vehicle rear side.
As shown in FIG. 5 and the like, the exhaust pipe 320 includes a flange 321, a first catalytic converter 322, a second catalytic converter 323, and the like. Further, a pair of exhaust pipes 320 are provided from the engine to the second catalytic converter 323 for each of the left and right banks of the engine so as to be substantially left and right, and merge on the rear side of the second catalytic converter 323.

The flange 321 is a part connected to the exhaust port of the engine.
Each of the first catalytic converter 322 and the second catalytic converter 323 is a three-way catalyst in which a noble metal such as platinum, rhodium or palladium is supported as a catalyst component on a carrier such as alumina. The upper part of the first catalytic converter 322 arranged on the upstream side is accommodated in a space portion between the left and right connecting members 240 in the cradle 200. In addition, the second catalytic converter 323 disposed on the downstream side is disposed below the floor panel 120.

The steering gear box 330 is provided with a rack and pinion mechanism that receives rotation of a steering wheel (not shown) via a steering shaft (not shown) and converts the rotational motion into a reciprocating motion in the vehicle width direction.
Tie rods 331 are provided on the left and right ends of the steering gear box 330, respectively.
The tie rod 331 is a transmission shaft that connects a steering rack (not shown) in the steering gear box 330 and a knuckle arm formed on a housing (not shown) of the left and right front wheels. The tie rod 331 pushes and pulls the knuckle arm to steer the front wheel during steering operation by the driver, and transmits the steering reaction force from the front wheel to the driver side.

The suspension arm 340 is attached to the cradle 200 so as to be swingable about an axis substantially along the longitudinal direction of the vehicle, and supports the lower end of the housing of the front wheel via a ball joint.
The suspension arm 340 includes a front bush 341 and a rear bush 342 that are spaced apart in the front-rear direction at the end of the vehicle body.
The front bush 341 and the rear bush 342 are attached to the front arm attachment portion 212 and the rear arm attachment portion 213 of the longitudinal member 210 in the cradle 200 using bolts and nuts, respectively.

As described above, according to the embodiment, the following effects can be obtained.
(1) By connecting the left and right longitudinal members 210 with the front lateral member 220 and the rear lateral member 230, and connecting the front and rear lateral members 220, 230 with the coupling member 240, one lateral passage is achieved. The load input to the members can be distributed and handled by the front and rear transverse members and efficiently transmitted to the left and right longitudinal members 210. For this reason, it is easy to ensure rigidity even when the transverse member is thinned to lower the mounting position of the engine. As a result, it is possible to reduce the center of gravity of the vehicle and improve the running performance. Further, the rear lateral member 230 formed in a curved shape is deformed by a lateral tensile load input from the suspension arm 340, or the rear lateral member 230 is bent by a compressive load. Although there is a concern, even in such a case, the load on the front lateral member 220 is also borne through the connecting member 240, thereby suppressing the deformation of the rear lateral member 230 and reducing the change in suspension geometry. Suspension performance can be improved.
(2) By disposing the rear bushing 342 of the suspension arm 340 in the vicinity of the connecting portion between the longitudinal member 210 and the rear transverse member 230, the lateral input acting on the longitudinal member 210 from the suspension arm 340 is received. This can be transmitted to the longitudinal member 210 on the opposite side, so that the rigidity of the attachment portion of the suspension arm 340 can be improved and the running performance of the vehicle can be further improved.
(3) By providing the engine mount 310 on the front lateral member 220 and attaching the steering gear box 330 to the rear lateral member 230, the load on the front and rear lateral members 220, 230 is distributed and the structure is lightweight. When the load is input, the rigidity can be ensured by transmitting the load between the front and rear transverse members 220 and 230 by the connecting member 240.
(4) By placing the engine mount 310 in the vicinity of the joint between the front lateral member 220 and the connecting member 240, a load input from the engine mount 310 to the front lateral member 220 can be efficiently input to the connecting member 240. Can do.
(5) Since the cross-sectional shape in the vicinity of the connection portion of the connecting member 240 with each of the transverse members 220 and 230 is continuously enlarged with respect to the intermediate portion, the load can be transmitted efficiently.
(6) By disposing the upper part of the first catalytic converter 322 in the interval between the left and right connecting members 240, the mounting position of the first catalytic converter 322 can be increased and the minimum ground clearance can be secured while effectively utilizing the dead space. .

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the technical scope of the present invention.
(1) The detailed structure of the vehicle body front part structure is not limited to that of the above-described embodiment, and can be changed as appropriate. For example, the shape, material, manufacturing method and the like of each member can be changed as appropriate.
(2) The cradle of the embodiment includes a pair of longitudinal members, lateral members, and connecting members, but the present invention is not limited to this, and for example, three or more longitudinal members, lateral members, A connecting member or the like may be provided. Further, other members may be added.
(3) In the embodiment, the engine mount is provided on the front lateral member of the cradle, and the steering gear box is attached to the rear lateral member. However, the arrangement of these components is not limited to this. For example, an engine mount may be provided on the rear lateral member, or a steering gear box or other parts may be attached to the front lateral member.
(4) In the embodiment, a part of the catalytic converter is accommodated in the gap between the left and right connecting members in the cradle. However, the present invention is not limited to this. For example, the protruding portion in the differential part of the engine oil pan or transaxle case Etc. may be accommodated. Further, other parts can be accommodated in the gap between the connecting member and the longitudinal member.

100 Body body 110 Toe board 120 Floor panel 121 Floor tunnel 130 Main frame 131 Front bracket 132 Rear bracket 140 Upper frame 150 Suspension support 160 Bumper beam 170 Radiator upper support 180 Radiator lower support 200 Cradle 210 Longitudinal member 211 Bracket 212 Front arm attachment Portion 213 Rear arm attachment portion 220 Front lateral member 230 Rear lateral member 240 Connecting member 250 Front end member 260 Lower member 310 Engine mount 320 Exhaust pipe 321 Flange 322 First catalytic converter 323 Second catalytic converter 330 Steering gear box 331 Tie rod 340 Suspension arm 341 Front bush 342 Rear Bush

Claims (5)

A main frame that protrudes forward from the front partition of the passenger compartment and is arranged on each of the left and right sides of the engine room
A vehicle body front structure comprising: a cradle attached to a lower portion of the main frame;
The cradle is
A pair of longitudinal members extending substantially along the vehicle front-rear direction and spaced apart in the vehicle width direction, respectively coupled to the lower portions of the left and right main frames;
A front lateral member extending substantially along the vehicle width direction and provided to the longitudinal member;
A rear lateral member that extends substantially along the vehicle width direction and is provided on the longitudinal member, and is disposed at a rear side with respect to the front lateral member;
A pair of connecting members that extend substantially along the vehicle longitudinal direction and are spaced apart in the vehicle width direction and connect the intermediate portion of the front lateral member and the intermediate portion of the rear lateral member ;
It is formed so as to be curved so that an intermediate part of the front lateral member and the rear lateral member is lifted,
At least a part of a catalytic converter for post-processing exhaust gas from an engine is disposed between the left and right connecting members . Comprising a suspension arm swingably attached to the cradle;
At least a part of the suspension arm mounting portion is disposed in the vicinity of the connecting portion between the longitudinal member and the front lateral member, or in the vicinity of the connecting portion between the longitudinal member and the rear lateral member. The vehicle body front part structure according to claim 1. An engine mount provided on the front lateral member and mounted with an engine;
The vehicle body front part structure according to claim 1, further comprising: a steering gear box attached to the rear lateral member. The vehicle body front part structure according to claim 3, wherein the engine mount is disposed in the vicinity of a joint portion between the front lateral member and the connecting member. 5. The connection member is formed by continuously expanding a cross-sectional shape in the vicinity of a connection portion between the front lateral member and the rear lateral member with respect to an intermediate portion. The vehicle body front part structure according to any one of the preceding items .

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