JP2567844B2 - Vehicle exhaust gas silencer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an exhaust gas silencer that is optimal for motorcycles and tricycles, for example, and in particular, the silencer has a predetermined diameter so that it can be installed in a limited space. The present invention relates to a structure in which a necessary introduction passage area can be ensured while being held.

[Conventional technology]

Generally, the exhaust pipe that exhausts the exhaust gas from the vehicle engine is formed to have a length according to the desired output characteristics, and the exhaust pipe has a shape and volume that can achieve the required silencing effect. A silencer is provided. Eg 2
As a muffler for a scooter type motorcycle equipped with a cycle engine, conventionally, by forming a first expansion chamber at the downstream end of an exhaust pipe and further forming a second expansion chamber at the downstream side thereof, There are some which are designed to secure the necessary volume and the like. On the other hand, the space for arranging the exhaust pipe and the silencer is restricted by the structure of the vehicle, etc., so it is important to secure the required length, volume, etc. in this limited space. However, in the above-mentioned conventional structure, since the first and second expansion chambers are sequentially connected to the exhaust pipe having a predetermined length, the entire exhaust device becomes long, and the necessary installation space becomes large. is there.

Therefore, as a silencer capable of reducing the installation space, conventionally, for example, a first expansion chamber is formed at the downstream end of an exhaust pipe, and a portion of the exhaust pipe upstream of the first expansion chamber is surrounded. Some have a second expansion chamber (Actual Kokoku 59-
(See Japanese Patent No. 5134). This conventional structure requires only a short length of the exhaust device, and has an effect of reducing the installation space.

[Problems to be solved by the invention]

By the way, in the conventional structure in which the second expansion chamber is formed on the upstream side, a cylindrical pipe is arranged in parallel with the exhaust pipe as an introduction passage for introducing the exhaust gas from the first expansion chamber to the second expansion chamber. It is common. Therefore, in order to secure the required introduction passage area, the diameter of the pipe must be increased. However, if this pipe has a large diameter, the diameter of the silencer as a whole increases. As mentioned above, since there is a restriction on the space for disposing the silencer, there is naturally a limit to increasing the diameter of this pipe, and it is difficult to secure the necessary introduction passage area with the conventional structure. There is a problem that it is difficult to secure the effect.

Therefore, an object of the present invention is to solve the above conventional problems,
An object of the present invention is to provide an exhaust gas silencer for a vehicle, which can maintain the diameter of the silencer at a predetermined size, that is, can secure a necessary passage area in a limited installation space, and can improve the performance and the silence effect.

[Means for solving problems]

According to the present invention, a tapered downstream rear end portion having a larger diameter toward the downstream side of the exhaust pipe 9 connected to the engine is inserted into the outer cylinder 12, and the inside of the outer cylinder 12 is placed in front of the outer cylinder 12. Expansion chamber located on the rear side of the outer cylinder 12 and surrounding the downstream end of the outer cylinder insertion portion (tapered tube) 11 of the exhaust pipe 9 by the two partition plates 13a and 13b arranged in 15, the second expansion chamber 16 located on the front side, and the third expansion chamber 19 located between them, and the introduction pipe
The third expansion chamber 19 is penetrated by 17 to communicate the first and second expansion chambers 15 and 16 with each other, and the second expansion chamber 16 is connected to the third pipe by the introduction pipe 20.
In the exhaust gas muffler of a vehicle, which communicates with the expansion chamber 19 and discharges the exhaust gas in the third expansion chamber 19 to the outside of the outer cylinder 12 via the tail pipe 21, The taper pipe 11 is attached so as to surround the third expansion chamber 19 portion to form a double pipe, and both ends of the introduction pipe 17 are fixed to the two partition plates 13a and 13b. 11
Is defined as an exhaust gas introduction passage 18 for introducing the exhaust gas from the first expansion chamber 15 to the second expansion chamber 16, and the gap is substantially constant in the exhaust gas flow direction, and the passage cross-sectional area is the exhaust gas flow. The introduction pipe 17 is tapered along the shape of the taper pipe 11 so that it becomes smaller toward the downstream side in the direction.
The front portion of 11 is fixed to the front end of the outer cylinder 12, and the rear end is fixed to the outer cylinder 12 via the support plate 13c in the first expansion chamber 15,
A cover pipe 23 is fitted in a portion of the tapered pipe 11 between the introduction pipe 17 and the support plate 13 to form a resonance chamber 22 surrounding the portion, and the tail pipe 21 is tangentially below the outer cylinder 12. It is characterized in that it is arranged so as to extend.

[Action]

In the vehicle exhaust gas silencer according to the present invention, since the introduction passage is formed by the double pipe structure in which the exhaust pipe is surrounded by the introduction pipe, it is possible to increase the passage area by slightly increasing the diameter of the introduction pipe. Can be greatly expanded. Therefore, since it is not necessary to increase the diameter of the silencer as a whole, the silencer can be held at a predetermined diameter while ensuring the necessary introduction passage area, and as a result, the required space can be prevented while the installation space is expanded. Output characteristics and noise reduction effect can be secured.

Further, when configuring the double pipe structure, the introduction pipe 17,
Since it is arranged so as to straddle between the first and second expansion chambers 15 and 16, that is, the third expansion chamber 19 located relatively in the front part of the outer cylinder 12, the introduction pipe 17 is provided in the front part of the taper pipe 11. Since it will be installed in the small diameter part, if the passage area is the same, the diameter of the introduction pipe 17 can be made smaller while making the gap between both pipes 17 and 11 larger than in the case of being installed in the rear part, and it is possible to reduce the weight and the passage. The cross-sectional area can be easily set and the degree of freedom in setting is high.

Furthermore, the outer surface of the introduction pipe 17 is fixed to the partition plates 13a and 13b, the front portion of the tapered pipe 11 is fixed to the front end of the outer cylinder 12, and the rear end is supported by the support plate 13c in the first expansion chamber 15. Since it is fixed to the outer cylinder 12, the introduction pipe 17 and the taper pipe 11 are
Since the pipes 17 and 11 are reliably supported firmly, the relative deflection of the two pipes 17 and 11 is prevented, and the gap can be increased, the passage area of the introduction passage 18 does not fluctuate even if there is a deflection. It has almost no effect on the flow of exhaust gas.

Further, since the introduction pipe 17 and the taper pipe 11 are fixed to the outer cylinder 12, respectively, no supporting member is required in the gap between the pipes 17 and 11, and the cross-sectional area of the exhaust gas passage 18 is not narrowed. Therefore, the outer diameter of the introduction pipe 17 does not increase.

Since the cover pipe 23 that surrounds the tapered expansion pipe 15 and constitutes the resonance chamber 22 is fitted in the inner portion of the first expansion chamber 15, the rigidity of the downstream end portion of the tapered pipe 11 itself becomes high. From the point of view, the above-mentioned shake can be prevented.

Furthermore, the tail pipe 21 is formed so as to extend downward in the tangential direction of the outer cylinder 12, and the pipe 21 allows the exhaust gas to be discharged to the third direction.
Since the exhaust gas is discharged from the expansion chamber 19 to the outside of the outer cylinder 12 immediately, that is, without passing through another expansion chamber, the exhaust gas is discharged from the third expansion chamber 19 located in the front part of the outer cylinder 12. While the tape pipe 21 is short, the structure for arranging the tail pipe 21 inside the outer cylinder 12 can be simplified. Further, the diameter of the outer cylinder 12 can be made smaller than in the case where the tail pipe 21 is arranged on the side of the taper pipe 11.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 are views for explaining an exhaust gas silencer according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a scooter type motorcycle in which the silencer of this embodiment is adopted, and a front fork 4 having a front wheel 3 attached to a lower end of a vehicle body frame 2 of the motorcycle 1 is rotatable. A unit swing type engine 6 having a rear wheel 5 attached to a rear end thereof is swingably supported at a substantially central lower portion thereof. A seat 7 is provided above the rear portion of the body frame 2.
Is mounted, and the lower side of the seat 7 is covered with a side cover 8.

An exhaust pipe 9 of the engine 6 extends rearward of the vehicle, and a rear end portion of the exhaust pipe 9 forms a part of the exhaust pipe, and a taper pipe having a larger diameter toward the rear (insertion portion in the outer cylinder). 11 is connected. An exhaust gas silencer 10 of this embodiment is constructed by fitting a cylindrical outer cylinder 12 having a bottom into the tapered plate 11.
The front end portion of the outer cylinder 12 is fitted and fixed to the connecting portion of the taper pipe 11 with the exhaust pipe 9, and the rear portion thereof is fixed to the rear end portion of the taper pipe 11 via a support plate 13c. A large number of communication holes 14 are formed in the plate 13c. A sound absorbing material 12a made of molded glass wool is attached to the inner surface of the outer cylinder 12, and a cup-shaped punching metal 12b is attached to the inner surface of the rear end portion of the sound absorbing material 12a. Above taper tube 11
First and second partition plates 13a and 13b are arranged between the outer cylinder 12 and the outer cylinder 12.

The inner space of the punching metal 12b and the space surrounded by the second partition plate 13b, the taper tube 11 and the outer cylinder 12 serve as a first expansion chamber 15. Since the communication hole 14 of the support plate 13c has a large opening area, it has little effect as a diaphragm. In addition, the resonance chamber 22 is provided in the first expansion chamber 15 portion of the taper pipe 11.
The cover pipe 23 that composes the
A large number of through-holes 11a are formed in the resonance chamber 22 portion of 11.

A space surrounded by the first partition plate 13a, the taper pipe 11 and the outer cylinder 12 serves as a second expansion chamber 16. Then, a portion between the first and second partition walls 13a, 13b of the tapered pipe 11 is fitted with a tapered introduction pipe 17 along the tapered pipe 11 to form a double pipe. The gap between 17 and the taper pipe 11 serves as an introduction passage 18 for introducing the exhaust gas from the first expansion chamber 15 to the second expansion chamber 16.

In addition, the introduction pipe 17, the first and second partition plates 13a and 13b, and the outer cylinder 1
The space surrounded by 2 and 3 is the third expansion chamber 19. An introduction pipe 20 for introducing exhaust gas from the second expansion chamber 16 to the third expansion chamber 19 is inserted and fixed to the first partition plate 13a. Furthermore, exhaust gas is introduced into the third expansion chamber 19 and the silencer 10
A tail pipe 21 for discharging to the outside is inserted and fixed.

 Next, the function and effect of this embodiment will be described.

In the muffler 10 of the present embodiment, the exhaust gas from the engine 6 is introduced into the taper pipe 11 through the exhaust pipe 9, and as shown by the arrow in FIG.
The sound of a predetermined frequency is muted when passing through 22, and then the first
It is introduced into the expansion chamber 15. The exhaust gas expands in the first expansion chamber 15 to absorb energy, and then is contracted and introduced into the second expansion chamber 16 through the introduction passage 18. The expansion in the second expansion chamber 16 further increases energy. Be absorbed. Then, the exhaust gas passes through the introduction pipe 20 while being contracted again, and is expanded again in the third expansion chamber 19 to absorb the energy, and then discharged from the tail pipe 21 to the outside.

In this case, in the conventional silencer, there was a problem that it is difficult to secure the required cross-sectional area of the introduction passage, but in the present embodiment, due to the double pipe structure in which the cylindrical introduction pipe 17 is fitted to the taper pipe 11. Since the introduction passage 18 is configured, the necessary passage area can be easily secured by slightly increasing the diameter of the introduction pipe 17 while keeping the diameter of the outer cylinder 12 as it is, and the desired output characteristics and silencing effect can be obtained. You can

Further, in the above-mentioned embodiment, the case of the exhaust gas silencer for the motorcycle has been described, but the present invention can be applied to the exhaust gas silencer for the motorcycle as well as other types of vehicle silencer.

〔The invention's effect〕

As described above, according to the vehicle exhaust gas silencer of the present invention, the exhaust gas introduction passage for introducing the exhaust gas from the first expansion chamber to the second expansion chamber is provided at the insertion portion of the exhaust pipe inside the outer cylinder. Since it has a double pipe structure surrounded by, the necessary introduction passage area can be easily secured without increasing the diameter of the silencer, and the desired silencing effect and output characteristics can be secured in a limited installation space. effective.

Further, since the gap of the exhaust gas introduction passage is substantially constant in the exhaust gas flow direction, and the introduction pipe is tapered along the tapered pipe so that the passage cross-sectional area becomes smaller toward the downstream side, the exhaust gas Energy can be gradually attenuated,
There is an effect that the sound deadening effect can be further improved.

Further, the outer surface of the introduction pipe is fixed to the partition plate, the front portion of the taper pipe is fixed to the front end of the outer cylinder, and the rear end is fixed to the first portion.
Since it is fixed to the outer cylinder by the support plate in the expansion chamber, the taper pipe and the introduction pipe can be prevented from swinging, the passage area of the exhaust gas introduction passage can be prevented from varying, and the influence of the variation on the exhaust gas flow can be prevented. There is.

Further, since the cover pipe that surrounds the first expansion chamber and constitutes the resonance chamber is fitted in the portion of the first expansion chamber of the tapered tube, the rigidity of the tapered tube itself is increased, and also from this point, the deflection of the tapered tube can be prevented.

Furthermore, since the tail pipe is arranged so as to extend downward in the tangential direction of the outer cylinder as a structure for discharging the exhaust gas outward from the third expansion chamber located in the middle of the outer cylinder, the tail pipe is short. The tail pipe can be easily arranged and the outer cylinder can be made small in diameter.

[Brief description of drawings]

1 to 3 are views for explaining an exhaust gas silencer according to an embodiment of the present invention. FIG. 1 is a sectional side view thereof, and FIGS. 2 (a) and 2 (b) are respectively II a- in Figure 1
II a line sectional view, II b-II b line sectional view, and FIG. 3 are side views of a scooter type motorcycle in which the silencer of the above embodiment is adopted. In the figure, 1 is a scooter type motorcycle, 6 is an engine, 9 is an exhaust pipe, 11 is a taper pipe (downstream rear end portion), 15 is a first expansion chamber, 16 is a second expansion chamber, 17 is an introduction pipe, 18 is an introduction passage.

Claims (1)

(57) [Claims] 1. A tapered downstream rear end portion having a larger diameter toward the downstream side of an exhaust pipe connected to an engine is inserted into an outer cylinder, and the inside of the outer cylinder is arranged at a front part of the outer cylinder. A first expansion chamber located on the rear side in the outer cylinder and surrounding the downstream end of the insertion portion (tapered tube) in the outer cylinder of the exhaust pipe,
It is divided into a second expansion chamber located on the front side and a third expansion chamber located between them, and an introduction pipe penetrates the third expansion chamber to communicate the first and second expansion chambers with each other. In the exhaust gas silencer for a vehicle, the expansion chamber is connected to the third expansion chamber by an introduction pipe, and the exhaust gas in the third expansion chamber is discharged to the outside of the outer cylinder through the tail pipe. A pipe is attached so as to surround the third expansion chamber portion of the taper pipe to form a double pipe, both ends of the introduction pipe are fixed to the two partition plates, and a gap between the introduction pipe and the taper pipe is exhausted. An exhaust gas introduction passage for introducing gas from the first expansion chamber to the second expansion chamber, wherein the gap is substantially constant in the exhaust gas flow direction,
In addition, the introduction pipe is tapered along the shape of the tapered pipe so that the cross-sectional area of the passage becomes smaller toward the downstream side in the exhaust gas flow direction, and the front end of the tapered pipe is fixed to the front end of the outer cylinder and the rear end is fixed. Is fixed to the outer cylinder via a support plate in the first expansion chamber, and a cover pipe constituting a resonance chamber is fitted in a portion of the taper pipe between the introduction pipe and the support plate so as to surround the portion. An exhaust gas silencer for a vehicle, wherein the tail pipe is arranged so as to extend downward in a tangential direction of an outer cylinder.