JPS60178919A - Muffler of vehicle - Google Patents

Abstract

PURPOSE:To enhance the silencing effect by arranging a plurality of exhaust induction pipes inside the muffler's cylindrical body having longitudinal section in the direction of the same longitudinal direction and jamming noise suppression material in the space defined between the exhaust induction pipes and the cylindrical body so as to increase the contacting area of the induction pipes with the noise suppressing material. CONSTITUTION:A plurality of exhaust induction pipes 12 and 13 are arranged inside the muffler's cylindrical body 5 having longitudinal section in the direction of the same longitudinal direction. Noise suppression material 11 covers the peripheries of the exhaust induction pipes 12 and 13 each having many holes 12a and 13a pored in the partial face thereof. The distance between each of said exhaust induction pipes 12 and 13 and the external periphery of the noise suppression material 11 is set to L1 and the distance L2 between the pipes 12 and 13 is set to be 1-2 times of the distance L1, whereby increasing the contacting area of the induction pipes 12 and 13 each with the noise suppression material 11.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) This invention relates to a muffler for a vehicle that is placed in a place where space is limited.

(Prior Art) As is well known, a muffler is connected to the rear end of an engine's exhaust pipe, and when exhaust noise passes through the muffler, it is muffled and emitted into the atmosphere.

For example, in a motorcycle that travels off-road, this muffler is connected to the rear part of an exhaust pipe that has an expansion chamber near the engine and is connected to a two-stroke engine to prevent it from coming into contact with obstacles when riding. It is placed above the ring.

Furthermore, in small-sized motorcycles, the displacement of the engine is small, and the length and width of the vehicle body are short, so there are certain limitations on the length and width of the muffler.

By the way, for the muffler, for example,
As shown in Japanese Patent No. 24, there is a device in which an exhaust pipe having a large number of holes around the circumference is covered with a sound absorbing material.

However, this muffler cannot be made thicker because the exhaust pipe is installed inside a cylinder with a vertically long cross section, and the sound-absorbing material that absorbs the energy of sound waves has a vertically long cross section, so the part away from the exhaust pipe is There was a problem that it could not be used effectively and the silencing effect could not be sufficiently exhibited.

(Objective of the Invention) This invention was made against the background of the above circumstances, and in a muffler placed in a place where space is limited, a plurality of exhaust conduit pipes are arranged in a longitudinal direction in a cylindrical body with a longitudinally elongated cross section. The object of the present invention is to provide a muffler for a vehicle that can effectively exhibit the silencing effect of a sound absorbing material by arranging the muffler.

(Structure of the Invention) In order to achieve the above-mentioned object, the present invention includes an exhaust conduit pipe having a number of holes around the circumference arranged in the axial direction inside a cylindrical body having a vertically elongated cross section, and the holes of the exhaust conduit pipe are covered. In a vehicle muffler equipped with a sound-absorbing material, a plurality of exhaust conduit pipes are arranged in the longitudinal direction of the cross-section of the cylinder inside the cylinder, and a sound-absorbing material is provided between the exhaust conduit pipes and the cylinder. It is characterized by being filled with wood.

(Example) Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings.

? , Fig. 1 is a side view of a motorcycle for off-road driving to which an embodiment of the present invention is applied, Fig. 2 is a sectional view of a muffler, Fig. 3 is a sectional view taken along the line ■-■ of Fig. 2, and Fig. 4 is I in Figure 2
V-TV cross-sectional view, Figure 5 is the V-■ cross-sectional view of Figure 2, Figure 6
The figure is a sectional view taken along line VI-VI in FIG.

In FIG. 1, reference numeral 1 denotes a two-stroke engine, and this engine 1 is mounted on a vehicle body frame 2. Exhaust pipe 3 connects to engine 1 from the front of the cylinder of 2-cycle engine 1.
It extends from the side to the rear.

This 2-cycle exhaust pipe 3 has a thicker part near the engine 1 to form an expansion chamber/hook 3a, and the rear end of this expansion chamber 3a becomes narrower, and a muffler A is connected to the rear end 3b. has been done.

This muffler A is placed on the right side of the vehicle body on one side of the rear wheels 4 to prevent it from coming into contact with obstacles while driving. In this way, this type of muffler A is disposed on the side of the vehicle body above the rear wheels 4, and is therefore configured so as not to protrude to the side or rear of the vehicle body.

That is, as shown in FIGS. 2 to 6, the cylindrical body 5 of the muffler A has a vertically elongated elliptical cross section, and a partition wall 6 is fixed to the inside of the cylindrical body 5 by welding. The rear end opening is closed by welding the cover plate 7, while the front end opening is closed by fixing the cover plate 8 with rivets 9.

An expansion chamber 10 is defined inside the cylinder 5 between the partition wall 6 and the cover plate 7 on the rear side. In addition, the partition wall 6 and the front cover plate 8
A sound absorbing material 11 is filled between the two. This sound absorbing material 1
1 has a vertically elongated elliptical cross section and absorbs the energy of sound waves.

The sound-absorbing material 1 must be able to withstand high temperatures and high-speed gas flows, and should be porous and have good sound-absorbing performance. Although glass wool is used in this embodiment, asbestos, rock wool, etc. may also be used.

Inside the cylindrical body 5, a pair of exhaust conduit pipes 12 and 1.3 are press-fitted into the partition wall 6 and the cover plates 7 and 8 in the axial direction, and are arranged side by side in the longitudinal direction of the vertically elongated cross section of the cylindrical body 5. . A large number of holes 12a and 13a are formed in the exhaust gas conduit pipes 12 and 13 in a portion covered with the sound absorbing material 11. Exhaust conduit pipe 12
．． Exhaust sound passing through the holes 12a and 13a is guided to the sound absorbing material 11, and the sound absorbing material 11 absorbs the sound energy and muffles the sound.

The exhaust gas conduit pipes 12, i3 and the outer periphery of the sound absorbing material 11 are set at a distance Ll as shown in FIG. It is set.

As a result, the outer periphery of the exhaust conduit pipe 12.13 and the sound absorbing material 11
The contact area with the holes 12a and 1 increases, and a large amount of exhaust gas is
3b can be supplied to the sound absorbing material 11, so that the sound waves are leveled and absorbed.

The exhaust conduit pipes 12 and 13 have large diameter holes 12b and 13b formed at different positions in the portion located in the expansion chamber 10, so that the expansion chamber 1o absorbs the energy of sound waves of different frequencies. There is.

On the front side of the cylindrical body 5, a connecting pipe 14 and a pair of exhaust pipes 12.
This connecting pipe 14 is connected to the rear end portion 3b of the exhaust pipe 3.The connecting pipe 14 extends rearward from the approximately central portion 14a of the exhaust pipe 3. The openings 12c and 13c of the exhaust conduit 12 and 13 are sequentially bent so that the opposite sides 14b and 14c are aligned with each other so that exhaust sound is smoothly guided to the exhaust conduit 12 and 13.

The muffler A is attached by fixing the mount 5a of the cylinder 5 and the mount 14d of the connecting pipe 14 to the vehicle body.

Next, the operation of this embodiment will be explained.

When the two-stroke engine 1 is driven, exhaust gas from the exhaust boat intermittently passes through the expansion chamber 3a of the exhaust pipe 3 and is emitted from the muffler A into the atmosphere.

When this exhaust gas passes from the connecting pipe 14 of muffler A to the exhaust conduit pipe 12.13, the sound energy of the exhaust gas is converted into a sound wave of a predetermined frequency that flows through the exhaust conduit pipe 12.13.
is introduced into the sound absorbing material 11 through small diameter holes 12a and 13a.

When the energy of this sound wave passes through a large number of holes in the sound absorbing material 11, the pair of exhaust conduit pipes 12 and 13 are arranged in the vertical direction of the cross section of the cylinder 5, and the contact area between the two is is increasing, and the exhaust conduit pipe 12.13
Since the distance Ll is set between the outer circumference of the sound absorbing material 11 and the distance L2 is set between the exhaust conduit pipes 12 and 13, a large amount of sound waves are absorbed within the sound absorbing material 11 on average.

Furthermore, when the sound waves pass through the portion of the exhaust conduit 12.13 located in the expansion chamber 10, the energy of the sound waves with different frequencies is absorbed in the expansion chamber 10 from the large diameter holes 12b, 13b formed at different positions. be done.

In this way, the sound wave energy of the exhaust gas is absorbed by the sound absorbing material 11 and the expansion chamber 1O when passing through the exhaust gas conduit pipes 12, 13, thereby reducing the exhaust noise released into the atmosphere.

(Effects of the Invention) As described above, the present invention includes a plurality of exhaust conduit pipes arranged in the longitudinal direction of the cross section inside the cylinder having a vertically elongated cross section, and a sound absorbing gap between the exhaust conduit pipes and the cylinder. By filling the sound absorbing material and increasing the contact area between the exhaust conduit and the sound absorbing material, sound energy can be absorbed in the entire sound absorbing material having a longitudinally elongated cross section.

Therefore, it is possible to effectively utilize the silencing effect of the sound absorbing material, and it is particularly effective in reducing exhaust noise in mufflers installed in places where installation space is limited or in small mufflers.

[Brief explanation of the drawing]

FIG. 1 is a side view of a motorcycle for off-road driving to which an embodiment of the present invention is applied, and FIG. 2 is a sectional view of a muffler.
Figure 3 is a cross-sectional view taken along ■-m in Figure 2, Figure 4 is a cross-sectional view of the connection to the exhaust pipe, Figure 5 is a cross-sectional view taken along line V-V in Figure 2, and Figure 6 is a cross-sectional view of the connection part with the exhaust pipe. ■-■ It is a sectional view. A... Muffler 5... Cylindrical body 6... Partition wall 7, 8... Cover plate 10... Expansion chamber 11... Sound absorbing material 12.13... Exhaust conduit pipes 12a, 13a...・Hole 14...When connecting pipe Applicant: Yamaha Motor Co., Ltd. Figure 3

Claims (1)

[Claims] In a vehicle muffler in which an exhaust conduit pipe having a number of holes around the circumference is disposed in the axial direction inside a cylindrical body with a vertically elongated cross section, and a sound absorbing material is provided to cover the holes of the exhaust conduit pipe, the cylinder with a vertically elongated cross section is provided. A vehicle muffler in which a plurality of exhaust conduit pipes are arranged in the longitudinal direction of the cross-section of a cylindrical body, and a sound-absorbing material is filled between the exhaust conduit pipes and the cylindrical body.