JP2966469B2 - Exhaust silencer for motorcycle - Google Patents

Description

The present invention relates to an exhaust muffler for a motorcycle.

[Prior Art] Conventionally, in an exhaust muffler for a motorcycle, since the outer cylinder of the muffler becomes hot due to the heat of exhaust gas, a heat insulating material such as glass fiber is wound between the expansion chamber and the outer cylinder. I have.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional silencer, since the outer cylinder of the silencer becomes hot due to the heat of the exhaust gas, carbon fiber, ceramic fiber, etc. applied to the outer surface of the silencer There is a risk of burning or discoloration of the fiber reinforced plastic, decorative plating, painting, etc. In order to lower the temperature of the outer cylinder, it is necessary to secure the thickness of the heat insulating material by that much, and the equipment becomes larger In addition, there is a problem that the cost increases.

In order to solve this problem, Japanese Utility Model Laid-Open No. 59-523 discloses a method in which a gap is provided between an inner cylinder and an outer cylinder, and a traveling wind is introduced from a slit-shaped outside air intake provided on an outer peripheral surface of the outer cylinder. And the air is discharged from the outlet provided on the outer peripheral surface.However, the amount of traveling wind flowing between the outer cylinder and the inner cylinder is small, and the surface temperature of the outer cylinder cannot be effectively reduced. Has disadvantages.

An object of the present invention is to solve the above-mentioned problem, and an object of the present invention is to provide an exhaust muffler for a motorcycle that can effectively prevent an outer cylinder of the muffler from becoming hot due to heat of exhaust gas. I do.

Means for Solving the Problems For this purpose, the exhaust muffler for a motorcycle according to the present invention includes a cylindrical exhaust muffler 22 which is disposed on the vehicle body side of the motorcycle with the axis line extending in the front-rear direction. Inner cylinders 27 and 28 in which a chamber 37 is formed, and annular ventilation / cumming spacers 40 and 41 having ventilation holes 40a and 41a protruding from the outer periphery of the front and rear portions of the inner cylinder, and the spacers. An outer cylinder 29 fixed at a predetermined interval to the outside of the inner cylinder via an outer surface, and having an outer surface wound with fiber-reinforced plastic; an exhaust outlet pipe 39 connected to a rear end of the inner cylinder; A front cover 42 having a tubular portion 42b fitted to the outer periphery of the front portion of the tube, the tubular portion being riveted to the outer tube, and formed at the tip of the tubular portion 42b, between the outer periphery of the inner tube. A reduced-diameter portion 42a that decreases in diameter so as to form an annular gap that opens forward, and is fitted around the rear outer periphery of the outer cylinder. A cylindrical portion 43b, which is rivet-fixed to the outer cylinder, and has a bottom portion 43c at the rear end of the cylindrical portion 43b located rearward of the rear end of the inner cylinder, and the exhaust portion is provided at the center of the bottom portion. The rear cover 43 is formed in the rear cover 43 through which the outlet pipe passes, and is formed in the exhaust outlet pipe penetrating portion of the rear cover. Reduced diameter part
43a, and the running wind is circulated between the inner cylinder and the outer cylinder, and the exhaust outlet pipe 39 is connected to the reduced diameter portion 43 of the rear cover.
It is characterized by projecting backward from a. The numbers added to the above configuration are to be compared with the drawings,
This does not limit the configuration of the present invention at all.

[Operation] In the present invention, for example, as shown in FIG. 1, the traveling air flows through the gap between the front cover 42 and the lid 31 and the ventilation holes of the ventilation 40a, 4
1a and the gas flows through the gap between the rear cover 43 and the exhaust outlet pipe 39, so that the outer cylinder 29 is effectively cooled.

Example An example of the present invention will be described below with reference to the drawings.

FIG. 3 shows an overall side view of the motorcycle according to the present invention. The body frame 2 of the motorcycle 1 includes a head pipe 3, an upper frame 4, a lower frame 5, a seat rail 6, a rear arm bracket 7, and the like. A front fork 9 is rotatably supported by the head pipe 3, and a front wheel 10 is mounted below the front fork 9. An engine 11 is mounted and fixed between the upper frame 4 and the lower frame 5, and a fuel tank 12 and a seat 13 are provided above the upper frame 4 and the seat rail 6.

A rear arm 15 is swingably supported by the rear arm bracket 7, a rear wheel 16 is rotatably mounted on the rear arm 15, and a shock absorber 17 is disposed between the rear arm 15 and the upper frame 4. I have. Exhaust pipe from engine 11
19 is connected to the mufflers 20 and 21 through the lower part of the vehicle body, further extends rearward and connected to the exhaust mufflers 22 and 23. These exhaust silencers 22 and 23 are fixed to a footrest mounting bracket 26 by a mounting band 25 so as to be inclined with the gas discharge port facing upward.

FIG. 1 is a cross-sectional view showing one embodiment of an exhaust muffler for a motorcycle according to the present invention, and FIG. 2 is a perspective view of a ventilation / spacer in FIG.

The exhaust silencer 22 (23) includes the first and second inner cylinders 2 (23).
7 and 28 and an outer cylinder 29. The outer cylinder 29 is wound with fiber reinforced plastic such as carbon fiber or ceramic fiber.

A second inner cylinder 28 is fixed to the outer periphery of the first inner cylinder 27 via a partition member 30, and a lid 31 is fixed to a front end of the first inner cylinder 27. A partition member 32 is inserted and fixed to the left half of the first inner cylinder 27, and a cut and raised piece 33 is cut and raised on the outer periphery of the first inner cylinder 27, and the cut and raised piece 33 contacts the partition member 32. The exhaust passage is formed as shown by the arrow in the drawing.

An exhaust pipe 35 is fixed to the right half of the first inner cylinder 27 via a fixing member 34, and a sound absorbing material 36 such as glass fiber is provided between the first inner cylinder 27 and the exhaust pipe 35. A large number of ventilation holes (not shown) are formed in a portion where the first inner cylinder 27 and the exhaust pipe 35 are in contact with the sound absorbing material 36, and a space is provided between the first and second inner cylinders 27 and 28. A chamber 37 is formed, and these components absorb exhaust noise. Further, an exhaust outlet pipe 39 is connected and fixed to the exhaust pipe 35.

Ventilation spacers 40 and 41 are fixed to the outer periphery of the second inner cylinder 28, and the outer cylinder 29 is fixed to the inner cylinder 28 via this. The front cover 42 and the rear cover 43 are fixed to the front and rear ends of the outer cylinder 29 by rivets 45. The front cover 42 and the rear cover 43 are arranged at an interval with respect to the lid 31 and the exhaust outlet pipe 39, respectively, to form a ventilation path. Further, as shown in FIG. 2, a plurality of ventilation holes 40a, 41a are formed in the ventilation spacers 40, 41. The exhaust silencer 22 (23) having the above configuration is provided with the lid 31 and the muffler.
The connection member 46 fixed to the rear end of 20 (21) is connected and fixed by a bolt 47.

In the present invention, in a cylindrical exhaust silencer 22 arranged with the axis in the front-rear direction on the vehicle body side of the motorcycle,
Inner cylinders 27 and 28 in which a muffling chamber 37 is formed, and annular ventilation / cumming spacers 40 and 41 having ventilation holes 40a and 41a protruding from the outer periphery of the front and rear portions of the inner cylinder, An outer cylinder 29 fixed at a predetermined interval outside the inner cylinder via the spacer, and having an outer surface wound with fiber-reinforced plastic;
An exhaust outlet pipe 39 connected to the rear end of the inner cylinder, and a front cover 42 having a cylindrical portion 42b fitted on the outer periphery of a front portion of the outer cylinder, the cylindrical portion 42b being riveted to the outer cylinder. A reduced-diameter portion 42a formed at the tip of the cylindrical portion 42b and reducing the diameter forward so as to form an annular gap that opens forward with the outer periphery of the inner cylinder.
And a cylindrical portion 43b fitted on the outer periphery of the rear portion of the outer cylinder,
The cylindrical portion 43b is riveted to the outer cylinder, and has a bottom portion 43c located rearward from the rear end of the inner cylinder at the rear end of the cylindrical portion 43b, and the exhaust outlet pipe 39 is made to pass through the center of the bottom portion 43c. A reduced diameter portion formed in the rear cover 43 and the exhaust outlet pipe 39 penetrating portion of the rear cover, and reduced in diameter rearward so as to form an annular gap that opens rearward between the outer periphery of the exhaust outlet pipe 39. 43a, so that the exhaust outlet pipe 39 projects rearward from the reduced diameter portion 43a of the rear cover.

Accordingly, the exhaust gas from the muffler 20 (21) is discharged from the exhaust outlet pipe 39 through the first and second inner cylinders 27 and 28 and the exhaust pipe 35 as shown by the solid line arrows in the drawing. At this time, the traveling wind
As shown by the dashed line arrow in the figure, the front cover 42 and the lid 31
, The ventilation holes 40a, 41a of the ventilation / cumming spacers 40, 41 and the clearance between the rear cover 43 and the exhaust outlet pipe 39, so that the outer cylinder 29 is effectively cooled. Also, the exhaust outlet pipe 39
The tar-like exhaust oil discharged from the gas outlet of
As shown by the dotted arrow in the figure, the rear cover 43 and the exhaust outlet pipe
39 gaps, ventilation holes 41a, 40a and front cover 42 and lid 31
Flows down through the gap, so that the surface of the outer cylinder 29 is prevented from being soiled.

[Effects of the Invention] According to the present invention described above, the gap between the outer circumference of the inner cylinder and the reduced-diameter portion of the front cover is opened forward in an annular shape.
The dynamic pressure of the traveling wind acts uniformly on the entire area of the gap, and the traveling wind can flow in without being biased to the ventilation passage formed between the inner cylinder and the outer cylinder. In addition, the reduced diameter portions of the front and rear covers are reduced in diameter to the front and rear, respectively, so that they act as a baffle plate, reducing vortices generated in the streamline of the traveling wind compared to a simple round hole or a window-shaped hole. Therefore, the traveling wind flowing through the ventilation path increases, and heat damage such as burning or discoloration of the fiber-reinforced plastic can be reliably prevented. In addition, if fiber reinforced plastic is wrapped around the outer surface of the outer cylinder, thermal conductivity is low, so it can be a measure against contact with the rider's leg,
In addition, the appearance of the muffler can be improved.

In addition, the inner cylinder not only covers the outer peripheral surface with the outer cylinder, but also the rear end surface is covered with the bottom of the rear cover, and the exhaust outlet pipe projects rearward from the reduced diameter portion, so that the inner cylinder has the rear end surface and the bottom portion. Since the traveling wind passing through the gap is caused to flow along the outer periphery of the exhaust outlet pipe by the reduced diameter portion, the exhaust gas is cooled and the noise reduction effect is further increased. Also, the reduced diameter portion makes the gap less visible, so that the appearance is not impaired.

Furthermore, since the front and rear covers are riveted to the outer cylinder, the front and rear covers that have been processed to reduce the diameter and the bottom and the outer cylinder that has been subjected to fiber-reinforced plastic processing are finally integrated. These processes can be easily performed, and there is no damage to the fiber-reinforced plastic as in the case where they are integrated by welding or the like.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the exhaust muffler for a motorcycle according to the present invention, FIG. 2 is a perspective view of a ventilation / spacer in FIG. 1, and FIG. 3 is an entire motorcycle according to the present invention. It is a side view. 22, 23 ... exhaust silencer, 28 ... inner cylinder, 29 ... outer cylinder, 39 ...
… Exhaust outlet tube, 40, 41 …… Ventilation spacer, 40a, 41a
…… Ventilation holes, 42 …… Front cover, 43 …… Rear cover, 42
a, 43a …… The reduced diameter part.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F01N 7/08 F01N 7/14

Claims (1)

(57) [Claims] 1. A tubular exhaust silencer disposed on the side of a motorcycle body with its axis line extending in the front-rear direction, comprising: an inner cylinder having a muffler chamber formed therein; and a front and rear portion of the inner cylinder. An annular ventilating spacer having a ventilation hole protruding on the outer periphery, and an outer cylinder having an outer surface fixed at a predetermined interval outside the inner cylinder through the spacer and wound with fiber-reinforced plastic An exhaust outlet pipe connected to a rear end of the inner cylinder; a front cover having a cylinder fitted into the outer periphery of a front part of the outer cylinder, wherein the cylinder is riveted to the outer cylinder; A reduced-diameter portion formed at the distal end of the cylindrical portion and reduced in diameter so as to form an annular gap that opens forward with the outer periphery of the inner cylinder, and a cylindrical portion fitted into the outer periphery of the rear portion of the outer cylinder. The tube portion is riveted to the outer tube, and is located at the rear end of the tube portion behind the rear end of the inner tube. A rear cover having an exhaust outlet pipe penetrating the center of the bottom part, and an annular shape formed in the exhaust outlet pipe penetration portion of the rear cover and opening rearward between the outer periphery of the exhaust outlet pipe. A reduced diameter portion that reduces the diameter of the rear cylinder so as to form a gap between the inner cylinder and the outer cylinder, and the exhaust outlet pipe projects rearward from the reduced diameter section of the rear cover. An exhaust muffler for a motorcycle, characterized in that: