JP2001323809A - Muffler of automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a muffler of an automobile that can be inserted into the lower surface of a car body without large change of a structure design of the car body, and does not disturb uniform diffusion and absorption of an impact force applied to the car body at a back collision time even when the car body structure is greatly right and left asymmetric, by effectively receiving the impact force even without causing cutting or falling off of an elastic holding member such as a mount rubber at the rear end collision. SOLUTION: In this muffler of the automobile disposed on the lower surface side of the car body, a plurality of pipes for inter-communicating extension chambers inside the muffler are extended in the back and forth direction of the car body, one end of at least one of the plurality of pipes is held in a projecting state backwardly from one end of the muffler. When a predetermined or stronger impact force is applied forwardly of the car body in relation to one end of the pipe, the pipe deforms in the front direction of the car body inside the muffler, and the other end of the pipe is pressed onto the other end of the muffler to contract and deform axially.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a muffler for an automobile, and more particularly, to an internal structure of a muffler disposed behind a vehicle body.

[0002]

Conventionally, a silencer (hereinafter, referred to as a muffler) 1 for silencing an explosive sound of an engine exhaust is
As shown in FIG. 6, it is often hung on the lower surface side of the rear part of the vehicle body via a plurality of mount rubbers 2, and the exhaust gas downstream of the catalytic converter 3 that purifies a specific component of exhaust gas discharged from the engine. The engine exhaust is introduced into the muffler from the rear exhaust pipe 4 connected to the side,
The engine exhaust is muffled by sequentially expanding, resonating, interfering, absorbing and cooling the engine exhaust.

[0003] The interior of such a muffler 1 has expansion chambers 7, 8, 9 partitioned by partitions 5, 6, as shown in FIG.
In addition, a pipe 10 communicating the rear exhaust pipe 4 with the expansion chamber 9, a pipe 11 having an opening 11 a on the peripheral surface, and a pipe 11 communicating the expansion chambers 7 to 9, and a sound absorbing part on the peripheral surface having the opening 12 a are provided. A material 13 is wound, and the tail pipe 12 that communicates from the expansion chamber 7 to the outside of the muffler 1 is fixed while being inserted therethrough. The arrows in the figure indicate the flow of engine exhaust.

[0004] By the way, as the performance required for automobiles, there is a growing demand for quietness inside and outside the vehicle interior. At present, there is a demand for improvement in muffler noise reduction efficiency.
As a measure to improve the noise reduction efficiency, increasing the muffler capacity is being studied. However, as shown in FIG. 6, the conventional muffler 1 is often disposed on one of the left and right sides of the rear of the vehicle body. Therefore, if an attempt is made to secure a volume necessary for noise reduction, there is a problem that the attachment of the large-sized muffler affects the frame structure of the vehicle body. Then, since the skeleton structure of the vehicle body is affected, the vehicle body structure becomes largely left-right asymmetric, and uniform diffusion and absorption of the impact force applied to the vehicle body at the time of a rear collision is prevented. Further, in an automobile requiring a muffler capacity that affects the skeletal structure of the vehicle body, it is conceivable that the arrangement of the muffler may cause a great obstacle to the structural design of the vehicle body. further,
Even if the impact force at the time of a rear collision is applied to the muffler 1,
Since the pipes 10, 11 and the tail pipe 13 disposed inside the muffler 1 are stretched to prevent deformation of the muffler 1 itself, there is a problem that the amount of deformation of the muffler 1 when receiving an impact force is small.

In order to solve such a problem, a muffler 1 is suspended from a lower surface of a rear portion of a vehicle body, and when an impact force is received from a rear side of the vehicle body, the exhaust is performed by cutting or falling off of a mount rubber 2. It is also conceivable to make the shock absorbing structure of the vehicle body uniform by separating the system, particularly the muffler 1, from the vehicle body.

However, when such a method is adopted, there is a risk that all of the mount rubber 2 holding the exhaust system may fall off, and the hot exhaust system that has completely fallen off may be safely held. You lose the way.
Further, in order to cause the mount rubber 2 to be cut off or fall off at the time of a rear collision, the muffler 1 is arranged so as to protrude from the lower surface of the vehicle body toward the road surface as appropriate. In addition to the above obstacles, the aerodynamic characteristics are deteriorated due to the disturbance of the air flow under the vehicle.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the conventional vehicle silencer, and has been described in the related art. By being able to be inserted and attached, and effectively receiving the impact force without cutting or falling off the elastic holding member such as the mount rubber at the time of a rear collision,
It is an object of the present invention to provide a muffler for an automobile that does not hinder uniform diffusion and absorption of an impact force applied to a vehicle body in a rear collision even when the vehicle body structure is largely asymmetric.

[0008]

In order to achieve the above object, the present invention relates to a muffler for a motor vehicle arranged on a rear lower surface of a vehicle body, wherein a plurality of mufflers communicating with an expansion chamber inside the muffler are provided. A pipe is disposed so as to extend in the vehicle front-rear direction, and at least one end of the plurality of pipes is held in a state protruding rearward from one end of the muffler, and When a predetermined or more impact force toward the front of the vehicle body is applied, the pipe displaces the inside of the muffler toward the front of the vehicle body, and the other end of the pipe comes into contact with the other end of the muffler. It is characterized by being contracted and deformed in the axial direction by being pressed.

The other end of the pipe is radially deformed by a compressive load when it comes into contact with the other end of the muffler, so that the entire length of the pipe is contracted. .

Further, the pipe has a double-pipe structure at one end and a single-pipe structure at the other end of the pipe, so that the pipe has a rigidity difference in the longitudinal direction of the vehicle body. It is characterized by.

Further, the pipe has a two-part structure in which cylindrical bodies having different diameters are added in the longitudinal direction of the vehicle body, and one end of the pipe is larger in diameter than the other end. The pipe is characterized in that the other end of the pipe is easily press-fitted into the one end.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a muffler (muffler) for an automobile to which the present invention is applied will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 1 is a side sectional view for explaining an internal structure of a muffler of the present invention, FIG. 2 is a side sectional view for explaining a configuration of a tail pipe of FIG. 1, and FIG. 3 is a tail in FIG. FIG. 4 is a perspective view showing a modification at the end of the pipe, FIG. 4 is a side sectional view showing an internal state of the muffler when a forward impact force is applied from behind the muffler in FIG. 1, and FIG. ,
It is the comparative figure which compared the crush load of the silencer of this invention with the thing of the prior art example. The same components as those of the conventional example are denoted by the same reference numerals.

As shown in FIG. 1, the muffler 14 of the present invention
Is disposed such that a front end portion (left side in FIG. 1) of a cylindrical main body portion 14a extending in the front-rear direction of the vehicle body, and a front end wall 14b and a rear end wall 14c at the rear end portion respectively close the open ends. . At a predetermined position on the inner surface side of such a main body portion 14a,
The partition walls 5, 6 are arranged in a direction orthogonal to the front-rear direction of the vehicle body, and partition the inside of the main body portion 14a into a plurality of chambers, so that expansion chambers 7, 8, 9 are formed.

Inside the muffler 14, a pipe 10 extending in the vehicle longitudinal direction so as to communicate the rear exhaust pipe 4 and the expansion chamber 9 exhausts predetermined positions of the front end wall 14b and the partition walls 5, 6. It is fixedly arranged in a state of being inserted so as not to leak. The expansion chambers 8 to 9 communicate with each other, and a predetermined area of the pipe 11 fixedly disposed in a state where the predetermined positions of the partition walls 5 and 6 are inserted so as not to cause exhaust leakage is provided to the expansion chamber 8 by engine exhaust. Are formed.

Further, inside the muffler 14, the expansion chamber 7 is provided.
A tail pipe 15 extending in the front-rear direction of the vehicle so as to conduct the engine exhaust to the outside of the muffler 14 is fixedly arranged in a state where predetermined positions of the partition walls 5, 6 and the rear end wall 14c are inserted so as to prevent exhaust leakage. Have been.

As shown in FIGS. 2 to 3A, the tail pipe 15 has an inner peripheral surface at the front end of a cylindrical main body 15A held by the partition walls 5, 6 and the rear end wall 14c. The outer peripheral surfaces of the rear ends of the cylindrical collapse portions 15B are connected to each other in such a manner that the outer peripheral surfaces are inserted by a predetermined distance.

First, the main body 15A will be described.
A plurality of apertures 15a having a predetermined diameter are formed in a circumferential surface of the substantially central portion of the main body 15A along the vehicle front-rear direction. Of the sound absorbing material 13 (for example, glass wool)
The sound absorbing material 13 is completely wound by a cylindrical outer tube 16 connected to the outer peripheral surface of the main body 15A.

The connecting force between the front end of the main body 15A and the partition wall 5 for holding the main body 15A inside the muffler 14, the connecting force between the outer tube 16 connected to the main body 15A and the partition wall 6, And a main body 15 at the rear of the outer tube 16.
When a predetermined or more collision load is input from the rear of the muffler 14 to the front, the main body 15A is displaced toward the front of the vehicle body when a predetermined collision load is input from the rear of the muffler 14 to the front. And a binding force that can be used. Also, due to such a coupling state, almost all parts of the main body 15A disposed inside the muffler 14 have a double pipe structure extending in the vehicle longitudinal direction, so that the rigidity of the main body 15A in the vehicle longitudinal direction is improved. Has been increased.

Next, the collapsed portion 15B will be described. The collapsed portion 15B is formed of a flat plate having a thickness smaller than the thickness of the main body portion 15A, and opposes one side of the flat plate in the longitudinal direction. The contact surface of both sides is formed into a tubular body by partial welding in a state of being wound so as to contact the side portion, and the outer peripheral surface side of the rear end portion of the collapse portion 15B is the front end portion of the main body portion 15A. It has a diameter that fits only a predetermined distance so that it can be easily inserted into the inner peripheral surface side, and is formed so that the rigidity in the vehicle front-rear direction is smaller than that of the main body 15A. Reference numeral 15Ba in FIG. 3 (a) indicates a non-welded portion on the contact connection surface of the collapsed portion 15B, and the non-welded portion 15Ba causes the strength of the connection force on the contact connection surface of the collapsed portion 15B to be weak. It is attached.

As a result, when a predetermined or more compressive load is applied to the front and rear ends of the tail pipe 15 shown in FIG. 3A in the vehicle longitudinal direction, the rigidity in the vehicle longitudinal direction is increased. The rear end of the collapsed portion 15B, which has low rigidity in the longitudinal direction of the vehicle body, is further press-fitted to the front end of the main body 15A, so that the front end of the main body 15A is fitted as shown in FIG. The abutting connection surface of the inserted collapsed portion 15B cannot withstand the compressive load, and the breakage is promoted from the abutting connection surfaces of both ends of the non-welded portion 15Ba, so that both sides are shifted so as to overlap each other. Then, the collapsed portion 15B whose diameter has been reduced and deformed is easily pressed into the inner peripheral surface side of the front end of the main body 15A.

As described above, the coupling force between the front end portion of the main body 15A and the partition wall 5, the coupling force between the outer tube 16 and the partition wall 6 coupled to the main body portion 15A, and the main body portion 15A behind the outer tube 16 And the rear end wall 14c of the muffler 14
When a rear impact load exceeding a predetermined value is input, the main body 15A has a coupling force capable of displacing the vehicle body forward inside the muffler 14, and the rear end of the collapsed portion 15B is provided at the front end of the main body 15A. The part is inserted inside. As a result, when a rear-end load greater than a predetermined value is applied to the rear of the muffler 14, the respective connecting forces of the main body 15A, the partition walls 5, 6 and the rear end wall 14c are exceeded, so that the connection inside the muffler 14 is performed. Main body 15 held
A is displaced toward the front of the vehicle body, and the collapse portion 15B inserted into the front end of the main body 15A collides with the front end wall 14b of the muffler 14. Displacement is front end wall 14
b, the main body 1
Most of the 5A has a double-pipe structure to increase rigidity in the longitudinal direction of the vehicle body, whereas the collapse portion 15B is a cylindrical body having a thickness smaller than the thickness of the main body 15A. The strength of the joining force of the abutting joint surface is increased or decreased by the non-welded portion 15Ba, so that the rigidity in the vehicle longitudinal direction is reduced, and a rigidity difference occurs in the vehicle longitudinal direction.

As a result, as shown in FIG. 4, the main body 15A, which is displaced to the front of the vehicle body due to a rear impact load applied to the rear end of the collapsed portion 15B, the displacement of which is prevented by the front end wall 14b. Further, by the press-fitting, the contact connection surfaces of the collapsed portion 15B cannot withstand the compressive load, and the breakage is promoted from the contact connection surfaces at both ends of the non-welded portion 15Ba. As a result, the collapse portion 15B is pressed into the inner peripheral surface side of the main body portion 15A displaced toward the front of the vehicle body while being reduced in diameter and crushed.
Thereby, as shown in FIG. 5, compared with the crush load value of the conventional muffler 1 (indicated by a dashed line in the figure),
The crushing load value (shown by a solid line in the figure) of the muffler 14 in the present invention can be greatly reduced,
It can be seen that the muffler 14 effectively absorbs the impact force applied from the rear of the vehicle body.

As described above, according to the present embodiment, the coupling force between the front end of the main body portion 15A and the partition wall 5, the coupling force between the outer tube 16 coupled to the main body portion 15A and the partition wall 6, and the outer tube 1
When a rear-end load greater than a predetermined value is applied, the main body 15A can be displaced forward in the muffler 14 toward the front of the vehicle body when the rear end wall 14c of the main body 15A and the rear end of the muffler 14 is coupled to each other. The tail pipe 15 is formed by inserting the rear end portion of the collapsed portion 15B into the front end portion of the main body portion 15A while having the coupling force. As a result, the structure design of the conventional muffler is not significantly changed, so that the muffler can effectively receive the impact force without affecting the quietness and the back pressure. Also, with the muffler becoming larger,
Even if the vehicle body structure becomes largely asymmetrical, transmission of the impact force applied to the vehicle body at the time of a rear collision is reduced, so that uniform diffusion and absorption of the impact force to the vehicle body are not hindered. Moreover, the muffler 14 can be inserted close to the lower surface of the vehicle body while minimizing the necessity of cutting or falling off the mount rubber 2 at the time of a rear collision. Is not a barrier to
It does not disturb the air flow under the vehicle.

The collapse portion similar to the tail pipe 15 may be formed at the end of the pipe 10 or at the end of the pipe 11. Also, the bellows-shaped ends for facilitating contraction deformation in the axial direction are connected to the respective pipes 10 and 1.
This may be achieved by integrally forming the components 1 and 15 or by forming a composite.

As a result, by adopting a structure in which the muffler absorbs shock when determining the structure of the vehicle, the degree of freedom in designing the shock absorbing structure around the muffler and at the rear of the vehicle, and the vicinity of the muffler, Effects such as improvement in space utilization can be obtained.

[0026]

As described above, according to the vehicle silencer of the present invention, it is possible to insert the muffler into the lower surface of the vehicle body without making a significant change in the structural design of the vehicle body, and at the same time, it is possible to mount the muffler at the time of a rear collision. By effectively receiving the impact force without causing the elastic holding member to cut or fall off, the vehicle does not hinder uniform diffusion and absorption of the impact force applied to the vehicle body during a rear collision, even if the body structure is significantly asymmetric. Can be provided.

[Brief description of the drawings]

FIG. 1 is a side sectional view illustrating an internal structure of a muffler according to the present invention.

FIG. 2 is a side sectional view for explaining a configuration of a tail pipe of FIG. 1;

FIG. 3 is a perspective view showing a modification of the end portion of the tail pipe in FIG. 2;

FIG. 4 is a side sectional view showing an internal state of the muffler when a forward impact force is applied from behind the muffler in FIG. 1;

FIG. 5 is a comparative diagram comparing the crushing load of the muffler of the present invention with that of the conventional example.

FIG. 6 is a side view showing one arrangement example of a conventional silencer.

FIG. 7 is a side sectional view showing an internal structure of a conventional silencer.

[Explanation of symbols]

 5, 6 Partition wall 7, 8, 9 Expansion room 10, 11 Pipe 13 Sound absorbing material 14 Muffler (muffler) 14a Main body 14b Front end wall 14c Rear end wall 15 Tail pipe 15A Main body 15a Opening 15B Collapse 15Ba Non-welded part 16 outer tube

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 3D038 BA14 BA16 BB01 BC02 BC23 3G004 AA00 AA01 BA00 CA04 CA11 CA13 DA07 DA09 DA14 EA00 EA01 GA06

Claims (4)

[Claims] 1. A muffler for an automobile disposed on a rear lower surface side of a vehicle body, wherein a plurality of pipes communicating with an expansion chamber inside the muffler are arranged so as to extend in a front-rear direction of the vehicle body. At least one end of the pipe is held in a state protruding rearward from one end of the muffler, and when an impact force of a predetermined amount or more directed toward the front of the vehicle body is applied to one end of the pipe, the pipe becomes And displacing the inside of the muffler in the forward direction of the vehicle body, and the other end of the pipe is pressed against the other end of the muffler and contracts and deforms in the axial direction. vessel. 2. The entire length of the pipe shrinks and deforms when the other end of the pipe is radially deformed by a compressive load when the other end of the pipe abuts on the other end of the muffler. The vehicle silencer according to claim 1. 3. The pipe has a rigidity difference in the longitudinal direction of the vehicle body by having a double pipe structure at one end of the pipe and a single pipe structure at the other end of the pipe. The vehicle silencer according to any one of claims 1 to 2, characterized in that: 4. The pipe has a two-part structure in which cylindrical bodies having different diameters are added in the vehicle longitudinal direction, and one end of the pipe is larger in diameter than the other end. The muffler according to any one of claims 1 to 3, wherein the pipe easily press-fits the other end of the pipe into the one end.