JPH048814A - Exhaust structure for vehicle - Google Patents

Abstract

PURPOSE:To surely bend a power plant frame downward so as to surely absorb an impact force which occurs upon vehicle-to-vehicle bumping, by specifying the support of a difference unit, the coupling between a power plant frame and the differential unit and the arrangement of catalysts. CONSTITUTION:A vehicle has a power plant frame 3 connecting between a power unit 1 on the front side and a differential unit 2 on the rear side. In this arrangement, the differential unit 2 is attached to a subframe 11, vertically swingably, by coupling a cylindrical part of an arm member 13 to a bracket 12 with a coupling pin 17. The vertical center of attachment of the power plant frame 3 onto the differential unit 2 by a bolt 8 is off downward from the coupling pin 17. Further, a catalyst 24 disposed in the exhaust pipe 22 is provided direct below the front part of the power plant frame 3, and the downstream part thereof is off widthwise of the vehicle from a position directly below the frame 3.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applied to a vehicle in which a power unit mounted on the front side of the vehicle and a differential mounted on the rear side are connected by a power plant frame. This paper relates to the exhaust system structure of a vehicle.

[Prior Art] In conventional vehicles, a power unit mounted on the front side and a differential mounted on the rear side are bent. Some systems are rigidly connected via a power plant frame with a U-shaped cross section that is highly rigid and flexible against torsion. This structure reduces engine vibration and suppresses differential wind-up vibration caused by torque reaction from the rear wheels, improving the vehicle's responsiveness when accelerating. It has become.

[Problem to be solved by the invention]

However, with the conventional structure described above, when an impact force acts on the vehicle body from the front and rear directions during a vehicle collision, this impact force is directly transmitted to the differential or power unit via the power plant frame, resulting in the impact The problem is that the absorption of

Therefore, it is possible to make the power plant frame bend in the event of a vehicle collision, but if the power plant frame is made to bend downward, there is a risk that the power plant frame will interfere with the exhaust system and will not be able to bend reliably. be. In addition, the exhaust system is equipped with a catalyst that generates high heat, and in order to block the heat of this catalyst, a structure such as a heat shield plate above the catalyst has conventionally been required. There is a need for a simplified configuration.

[Means to solve the problem]

In order to solve the above problem, the exhaust system structure for a vehicle according to the invention of claim 1 includes a power unit provided on the front side of the vehicle and a horizontal member disposed in the width direction of the vehicle. An exhaust system for a vehicle in which the differential installed on the rear side of the vehicle is connected by a power plant frame, and the exhaust system connected to the engine has a catalyst that purifies exhaust gas. In terms of structure, the following measures have been taken.

That is, the above-mentioned differential is swingably supported by a pin member extending in the vehicle width direction on the front side of the horizontal member,
The power plant frame is connected to the differential at a position shifted downward from the pin member, and a catalyst is provided below the power plant frame at a position that overlaps with the power plant frame when viewed from above, and a catalyst is provided in the exhaust system. The downstream side of the list is located at a position offset from directly below the power plant frame in the vehicle width direction.

In order to solve the above problem, the vehicle exhaust system structure according to the invention of claim 2 has the following features in the structure of claim 1:
The exhaust pipe of the exhaust system is characterized in that a portion corresponding to the rear part of the power plant frame is supported by a support member that passes below the power plant frame and is connected to a vehicle body side member via an elastic body.

[For production]

According to the structure of claim 1, when an impact force in the longitudinal direction is applied to the power plant frame due to a vehicle collision, the differential is made swingable by the pin member extending in the vehicle width direction on the front side of the horizontal member. Since the power plant frame is supported and connected to the differential at a position shifted downward from the above-mentioned pin member, the differential rotates downward, and therefore the power plant frame moves downward at the rear of the differential side. It will bend to. At this time, since the downstream side of the catalyst in the exhaust system is located at a position offset from directly below the power plant frame in the vehicle width direction, there may be a situation where the downward bending of the power plant frame is obstructed by, for example, the exhaust pipe. is avoided. As a result, for example, when a vehicle collides head-on, the power unit can move rearward, and the impact can be reliably absorbed. Furthermore, since the power plant frame bends downward due to the impact force of the collision, it is possible to avoid a situation where the broken power plant frame rushes into the vehicle interior. Furthermore, since the exhaust system catalyst is provided below the power plant frame at a position that overlaps with the power plant frame when viewed from above, the heat radiation from the high-temperature catalyst toward the floor panel of the vehicle body is removed. It can be shielded by a plant frame.

According to the structure of claim 2, in addition to the above-mentioned effect, when the power plant frame is bent downward,
The power plant frame is once held by the support member, and this support member is connected to the vehicle body side member via an elastic body, so that the impact when the power plant frame is bent downward is applied to the support member and the elastic body. absorbed by a structure consisting of Therefore, for example, when a vehicle collides head-on and the power unit moves rearward, sudden movement of the power unit is prevented, and the shock absorption function at the time of the collision is improved.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 14.

For example, in an FR (front engine/rear drive) type vehicle, as shown in Figs. It has a plant frame 3. The power unit 1 described above is a unit made up of an engine, a clutch, and a transmission. The power unit 1 and the differential 2 are connected by a drive shaft 4, so that engine power is transmitted to the rear wheels.

The above power plant frame 3 is shown in FIGS. 3 and 4.
As shown in the figure, two plate members 5 and 6 are joined to each other.
It is formed into a U-shaped cross section that is open laterally, with flanges 3b and 3C extending horizontally at the upper and lower ends of the upright part 3a, and has high bending rigidity and flexibility against twisting. It has become a thing. The above plate member 5
6 are joined to each other at the upper and lower flange portions 3b and 3C, as shown in FIGS. The central parts of the intermediate part in the vertical direction are joined to form a joined part A, while a closed cross section B is formed in approximately the lower half of the front end and the rear end, and the upper and lower parts of the intermediate part. There is. With this structure, it is possible to balance the bending rigidity and torsional flexibility of the power plant frame 3 as a whole.

As shown in FIGS. 3 and 4, the front end of the power plant frame 3 has upper and lower flange portions 3b and 3C attached to the mounting portion 1a formed on the power unit 1 with bolts 7.
・It is connected to the power unit) 1 by being fastened at. The rear end portion of the power plant frame 3 is connected to the differential 2 by fastening upper and lower flange portions 3b and 3C to a mounting portion 2a formed on the differential 2 with bolts 8. The vertical attachment of the power plant frame 3 to the differential 2 using the bolts 8 above is centered so that the power plant frame 3 bends downward when a longitudinal impact is applied to the power plant frame 3. Therefore, as shown in Figure 4, when viewed from the side,
The differential 2 is attached to a subframe 11, which will be described later, at a point, that is, at a position shifted downward from the connecting pin 17. On the other hand, the attachment of the power plant frame 3 to the differential 2 in the left-right direction using the bolts 8... is centered so that the power plant frame 3 will bend laterally when a longitudinal impact is applied to the power plant frame 3. In order to
As shown in the figure, the power plant frame 3 is offset laterally from the center of the power plant frame 3 when viewed from above.

Further, as shown in FIG. 3, the power plant frame 3 has a bent portion 3d bent in the direction of the drive shaft 4 at a position in front of the connection portion with the differential 2 and near the connection portion. Therefore, when viewed from above, the power plant frame 3 has a substantially doglegged shape near the bent portion 3d, and is more likely to bend laterally due to an impact force in the front-rear direction. Furthermore, as shown in FIGS. 3, 4, and 9, the bent portion 3d has a recess 3e recessed in the direction of the drive shaft 4, and by having this recess 3e, the power plant The frame 3 is more easily bent laterally from the bent portion 3d due to an impact in the front and back direction. In this embodiment, the recess 3e also serves as a recess for avoiding the protrusion of a bolt for fixing the rear seat to the floor panel of the vehicle body.

On the other hand, the differential 2 is attached to the front part of a subframe 11 as a horizontal member, as shown in FIG. The subframe 11 has a structure with a highly rigid closed cross section, extends in the vehicle width direction, and is connected to, for example, a double wishbone type suspension device 10 shown in the figure.

Two U-shaped brackets 12 are provided on the front surface of the subframe 11.

On the other hand, an arm member 13 for attaching the differential 2 to the subframe 11 is provided at the upper end of the differential 2. This arm member 13 has two arm parts 14 that are curved and extend rearward, and a cylindrical part 15 that is provided at the rear end of the arm part 14 and whose axial direction is in the vehicle width direction. . A rubber bushing 16 having a pin insertion hole is provided inside the cylindrical portion 15. And the differential 2 is the arm member 1
The cylindrical portion 15 of No. 3 is connected to the bracket 12 by a connecting pin 17 as a pin member, so that it is attached to the subframe 11 so as to be swingable in the vertical direction with the vehicle width direction as the axial direction.

An exhaust system 21 is provided below the power plant frame 3, as shown in FIGS. 1 and 2. In this exhaust system 21, a front end portion of an exhaust pipe 22 extending in the longitudinal direction of the vehicle is connected to an exhaust manifold of an engine (not shown).

In the exhaust pipe 22, from the upstream side to the downstream side, there is a direct-coupled catalyst 23 for purifying exhaust gas immediately after the engine starts, a main catalyst 24 and a silencer 25 for this direct-coupled catalyst 23. They are arranged in order. The catalyst 24 described above is provided almost directly below the front part of the power plant frame 3, and the downstream part of the catalyst 24 in the exhaust system 21 is such that the exhaust pipe 22 bends diagonally from the downstream side of the catalyst 24. As a result, it is shifted from directly below the power plant frame 3 in the vehicle width direction.

Further, as shown in FIGS. 1, 2, and 11, below the front side of the recess 3e at the rear of the power plant frame 3, there is a rod-shaped bracket 26 as a support member for supporting the exhaust pipe 22. is provided. The bracket 26 extends in the vehicle width direction below the power plant frame 3 and is connected to the exhaust pipe 22 at one end. The other end of the bracket 26 is connected to a hanger 28, which is a vehicle body side member, via a rubber 27, which is an elastic body. This hanger 28 is connected to a side end of a tunnel portion 29a in the floor panel 29. As shown in FIG. 12, the above rubber 27 has a bracket insertion hole 27a at the bottom, a hanger insertion hole 27b at the top,
A bracket 26 and a hanger 28 are attached to both types of through holes 27a and 27b with their respective enlarged diameter portions 26a and 28a penetrating on opposite sides.

In the above configuration, if a longitudinal impact force is applied to the vehicle due to a vehicle collision, the power plant frame 3
As shown in FIG. 13, while bending laterally from the bent portion 3d, from the bent portion 3d which has become weaker due to the bending, it bends downward as shown in FIG. 14.

For example, when a vehicle collides head-on, the impact force applied to the power unit 1 is applied to the power plant frame 3. At this time, the attachment of the power plant frame 3 to the differential 2 in the left-right direction is such that the center is shifted to the side from the center of the power plant frame 3, and the connecting portion of the power plant frame 3 to the differential 2 is The above three powers are due to the fact that a bent part 3d bent in the direction of the differential 2 is formed near the front connection part, and a recessed part 3e recessed in the direction of the drive shaft 4 is formed in the bent part 3d. Due to the structure that makes it easy to bend the plant frame 3 laterally, the power plant frame 3 first bends laterally.

Next, differential 2 for subframe 11
Since the attachment of the power plant frame 3 to the differential 2 is centered downward with respect to the connecting pin 17, the differential 2 rotates downward due to the above-mentioned impact force, and therefore, The power plant frame 3 is bent downward. At this time, the exhaust system 21 below the bent portion 3d of the power plant frame 3
is placed offset from directly below the power plant frame 3 in the vehicle width direction, so the power plant frame 3
is bent downward without interfering with the exhaust system 21.

Next, the power plant frame 3 bent downward is temporarily held by the bracket 26, and then falls further downward as the rubber 27 breaks.

As described above, in the configuration of the present invention, the power plant frame 3 is bent by an impact force in the front and rear directions, so that when a vehicle collides head-on, for example, the power unit 1 can move backwards and Since the power plant frame 3 is finally bent downward, it is possible to avoid a situation where the tip of the broken power plant frame 3 rushes into the vehicle interior.

Further, the downward bending of the power plant frame 3 is caused by the fact that the exhaust system 21 below the bending part of the power plant frame 3 is arranged to be offset from directly below the power plant frame 3 in the vehicle width direction.
This is guaranteed to happen. In addition, in this embodiment, when the power plant frame 3 is subjected to an impact in the longitudinal direction, it first bends in the lateral direction, and when it becomes weaker, it bends downward. The power plant frame 3 is bent downward more reliably.

Moreover, since the power plant frame 3 bent downward is held by the bracket 26, the power plant frame 3 may suddenly fall, i.e.
For example, it is possible to suppress sudden rearward movement of the power unit 1, and it is possible to exhibit an even higher shock absorption function.

On the other hand, since the catalyst 24 is provided almost directly below the power plant frame 3, the heat generated by the catalyst 24 is shielded by the power plant frame 3.
For example, it is difficult for the light to be transmitted to the floor panel, that is, to the interior of the vehicle.

〔Effect of the invention〕

As described above, in the vehicle exhaust system structure according to the invention of claim 1, the differential is swingably supported by the pin member extending in the vehicle width direction on the front side of the horizontal member, and the power plant frame is supported as described above. A catalyst is connected to the differential at a position shifted downward from the pin member, and a catalyst is provided below the power plant frame at a position overlapping the power plant frame when viewed from above,
In this configuration, the downstream side of the catalyst in the exhaust system is located at a position offset in the vehicle width direction from directly below the power plant frame.

As a result, when a longitudinal impact force is applied to the power plant frame due to a vehicle collision, the power plant frame can reliably bend downward without being obstructed by the exhaust system, such as the exhaust pipe, thereby reducing the impact force. Absorption can be ensured. Further, the power plant frame can shield heat radiation from the high-temperature catalyst toward the floor panel of the vehicle body.

The exhaust system structure for a vehicle according to the invention set forth in claim 2 is such that, in the configuration set forth in claim 1, a portion of the exhaust pipe of the exhaust system that corresponds to the rear part of the power plant frame passes under the power plant frame and is elastic. This configuration is supported by a support member that is connected to the vehicle body side member through the body.

As a result, in addition to the effect of the structure of claim 1,
Since the power plant frame bent downward can be temporarily supported by the support member connected to the vehicle body side member via the elastic body, it is possible to provide an even higher impact absorption function.

[Brief explanation of drawings]

1 to 14 show an embodiment of the present invention. FIG. 1 is a plan view showing the exhaust system structure of a vehicle according to the present invention. FIG. 2 is a front view of the same. FIG. 3 is a plan view showing a power plant frame that connects the power unit and the differential. FIG. 4 is a front view of the same. Figures 5 to 9 are a cross-sectional view taken along the line E-E, a cross-sectional view taken along the line F-F, a cross-sectional view taken along the line -G, and a cross-sectional view taken along the line H-G in Figure 4, respectively.
-H arrow sectional view and I-1 arrow sectional view. FIG. 10 is an exploded perspective view showing the structure of attaching the differential to the subframe. FIG. 11 is a sectional view taken along the line JJ in FIG. 1. FIG. 12 is a perspective view of the rubber shown in FIG. 11. FIG. 13 is a schematic plan view showing a state in which the power plant frame is bent laterally. FIG. 14 is a schematic front view showing the power plant frame bent downward. 1 is a power unit, 2 is a differential, 3 is a power plant frame, 4 is a drive shaft, 11 is a subframe (horizontal member), 12 is a bracket, 17 is a connecting pin (pin member), 21 is an exhaust system 22 is an exhaust pipe, 24 is a catalyst, 26 is a bracket (supporting member), and 27 is a rubber (
28 is a hanger (vehicle body side member).

Claims (1)

[Claims] 1. A power unit provided on the front side of the vehicle;
A vehicle is equipped with a power plant frame that supports a horizontal member disposed in the vehicle width direction and connects a differential installed on the rear side of the vehicle with an exhaust system connected to the engine that collects exhaust gas. In the exhaust system structure of a vehicle that has a catalyst that purifies the air, the above-mentioned differential is swingably supported by a pin member extending in the vehicle width direction on the front side of the horizontal member, and the power plant frame is supported by the above-mentioned pin member on the front side of the horizontal member. A catalyst is connected to the differential at a position shifted downward from the member, and a catalyst is provided below the power plant frame at a position overlapping the power plant frame when viewed from above.The downstream side of the catalyst in the exhaust system is connected to the differential. A vehicle exhaust system structure characterized by being arranged at a position offset from directly below the frame in the vehicle width direction. 2. The portion of the exhaust pipe of the exhaust system that corresponds to the rear part of the power plant frame is supported by a support member that passes below the power plant frame and is connected to the vehicle body side member via an elastic body. An exhaust system structure for a vehicle according to claim 1.