JP2608428B2 - Exhaust muffler device for scooter type motorcycle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention prevents the generation of noise (shell sound) due to the vibration of the outer cylinder of a cylindrical exhaust muffler attached to a power unit, and improves cooling performance. The present invention relates to an improved exhaust muffler device for a scooter type motorcycle.

(Background of the Invention) In a scooter type motorcycle, noise may be generated due to the vibration of the exhaust muffler itself. For example, a so-called shell sound is generated due to the vibration of the outer plate of the muffler. One way to prevent such noise from occurring is to increase the rigidity of the muffler itself, but in order to prevent noise sufficiently, the outer cylinder must also be made sufficiently thick. Is increased.

Further, in the scooter type motorcycle, since the exhaust muffler is usually attached to the power unit and the upper part of the power unit is covered with the vehicle body cover, there is a problem that the cooling performance of the exhaust muffler is deteriorated.

(Object of the Invention) The present invention has been made in view of such circumstances,
It is an object of the present invention to provide an exhaust muffler device for a scooter-type motorcycle which can suppress the generation of noise such as shell noise while relatively reducing the increase in weight, and can improve the cooling performance due to traveling wind. .

(Constitution of the Invention) According to the present invention, it is an object of the present invention to hold one rear wheel at a rear end of a transmission case extending rearward from one side of an engine, and the front end is pivotally supported by a body frame so as to be vertically swingable. The exhaust muffler device for a scooter-type motorcycle, comprising: a power unit; and a substantially cylindrical exhaust muffler which is located on the opposite side of the transmission case with the rear wheel interposed therebetween and is inclined forward and downward and attached to the power unit. Insulating material that closely adheres to the outer cylinder of the muffler, and a cylindrical fastening plate that clamps the outer cylinder from the outside with the insulating material interposed therebetween, and the front part of the outer cylinder is positioned near the front edge of the fastening plate. In the front, the diameter is reduced to a substantially conical shape, and the heat insulating material is divided in the circumferential direction of the outer cylinder to form a gap between the outer cylinder and the fastening plate with an opening in the front-rear direction. Forms a number of small holes facing this gap and This is achieved by a scooter-type motorcycle exhaust muffler device, wherein the covering protector is mounted via a rubber bush.

(Embodiment) FIG. 1 shows an embodiment of the present invention.
FIG. 2 is a left side view of the two-wheeled scooter to which the present invention is applied, FIG. 3 is a right side view of the power unit, and FIG. 4 is a development view taken along the line IV-IV in FIG. It is.

In FIG. 2, reference numeral 10 denotes a body frame, which includes a steering head pipe 12, one main tube 14 descending from the head pipe 12 and extending rearward, and a pair of left and right rear tubes 16 (one Only appears). The rear tube 16 has a front end fixed to the main tube 14, and a portion parallel to the main tube 14 at the rear is fixed to the main tube 14 by a pair of front and rear brackets 18, 20. That is, the brackets 18, 20 protrude left and right from the main tube 14, and the left and right rear tubes 16 are fixed to the ends thereof. 22 is a front fork held by the head pipe 12,
24 is a front wheel, 26 is a steering handlebar.

2 and 3, a power unit 30 includes a forced air-cooled two-cycle single-cylinder engine 32 and a transmission case 34 extending rearward from the left side of the engine 32 and integrated with the engine 32. A rear wheel 50 is cantilevered on one side of the rear part of the transmission case 34, that is, on the right side. Transmission case
A V-belt continuously variable transmission 52 for transmitting the rotation of the engine 32 to the rear wheel 50 is accommodated in the 34. That is, the crankshaft of the engine 32 is disposed in the vehicle body direction, and the drive pulley 54 in the transmission case 34 is attached to the left end thereof. The belt winding radius of the drive pulley 54 changes according to the rotation speed, and the speed is set. The rotation of the driven pulley 56 is transmitted to the rear wheel shaft 60 via the reduction gear 58, and the rear wheel 50 fixed to the rear wheel shaft 60 rotates. This power unit
The front end of 30 is connected to the vehicle body frame 10 via a link 62 so as to be vertically swingable, and the rear end is elastically supported by a cushion unit 64.

The engine 32 has a crankcase 36
A shroud 66 is attached so as to cover the right side of the vehicle.
A fan (not shown) at the right end of the crankshaft of the engine 32
The shroud 66 has a circular outside air inlet 68 (FIG. 3) formed on the right side thereof facing the fan. The outside of the outside air intake 68 is covered with a cover 70. As shown in FIG. 3, the cover 70 has openings 72a and 72b formed on the outer peripheral side of the outside air inlet 68.

74 is an exhaust pipe, and 76 is an exhaust muffler. The exhaust pipe 74 is bent so as to surround the lower part of the engine 32 from the front of the engine 32. An exhaust muffler 76 and an exhaust pipe 74 are integrally formed, and a substantially triangular bracket 78 shown in FIG. 3 fixed to them is fixed to a crankcase of the engine 32 by two bolts 80a and 80b. Here, the exhaust muffler 76 has a cylindrical shape, and is located on the opposite side of the transmission case 34 with the rear wheel 50 interposed therebetween. Further, the exhaust muffler 76 is attached so as to be inclined forward and downward.

Next, the exhaust muffler 76 will be described. The muffler 76 is of a cylindrical type, and the outer cylinder 82 has a cylindrical fastening plate 86 via an insulating material.
It has been tightened by. That is, when the fastening plate 86 is expanded, it is made of a square heat-resistant stainless steel plate as shown in FIG.
Four L-shaped fasteners 88 are fixed to the opposing edges when wound around the outer cylinder 82. The inner surface of the fastening plate 86, that is, the outer cylinder 82
Molded glass wool 90 (90a, 90b, 90c) as a heat insulating material divided into three parts in the circumferential direction is adhered to the surface facing the. Long gaps 92a and 92b in the axial direction of the outer cylinder 82 are formed between the glass wools 90a and 90b and between 90b and 90c. Two rectangular windows 94 are opened in the gap 92a. Two trapezoidal bridges 96 are fixed to the outer surface of the fastening plate 86 so as to straddle the window 94 in the circumferential direction by spot welding or the like. It is installed. Two trapezoidal bridges 100 facing the rubber bush 98 are fixed to the outer cylinder 82 in the axial direction.
Is to be held.

Two round holes 104 are opened in the gap 92b between the glass wools 90b and 90c (FIG. 4).
06 are attached (FIG. 1). 108 in FIG.
Is a protector that is long in the axial direction.
Penetrates the two rubber bushes 106, 106
It is elastically attached to the tightening plate 86 by screws 110 (only one is shown) which is screwed into a projection nut fixed to the back surface of the pad 108. A number of small holes 112 are opened in the gap 92b in the fastening plate 86, so that the cooling performance by the traveling wind is improved.

Thus, molded glass wool 90, rubber bushes 98, 10
6.The cylindrical fastening plate 86 with the protector 108, etc., is mounted on the outer cylinder 82 of the muffler 70 while spreading the opposing edge while moving it in the axial direction, and the fastening plate 86 is attached to the outer cylinder 82 by the screw 102. Positioned and fixed. Then, the fastening plate 86 is fastened to the outer cylinder 82 by inserting and screwing the screw 114 into the opposed fastening member 88. As a result, the vibration of the outer cylinder 82 of the muffler 76 is suppressed, and the noise from the muffler 76, in particular, the generation of a shell sound is prevented.

As shown in FIG. 3, the front and rear portions of the outer cylinder 82 are reduced in diameter in a substantially conical shape in front and rear from the vicinity of the front and rear edges of the fastening plate 86, respectively. Therefore, the traveling wind is guided from the lower front of the power unit to the substantially conical outer surface of the front part of the outer cylinder 82 and enters the gaps 92a and 92b well.
The traveling wind passing through a and 92b is guided to the substantially conical outer surface at the rear of the outer cylinder 82 and is smoothly discharged. As a result, the cooling performance of the exhaust muffler 76 is improved.

Further, since a number of small holes 112 facing the gap 92b are provided in the tightening plate 86, the air in the gap 92b flows out from the small holes 112, and the cooling performance is further improved. Since the protector 108 that covers the small hole 112 is attached here via the rubber bush 106, the air that has exited the small hole 112
It is guided by the traveling wind passing between 6 and the protector 108 and smoothly flows backward. The protector 108 is a rubber bush 106
The heat of the clamping plate 86 is hardly transmitted to the protector 108.

Further, since the molded glass wool 90 is used as the heat insulating material, the assemblability is good and desirable, but the present invention is not limited to this.

In FIG. 2, reference numeral 120 denotes a main stand, and the stand 120 is supported by a lower portion of the crankcase almost directly below the crankshaft. 122 is an air cleaner, 124
Is a fuel tank, and 126 is a lubricating oil tank.

(Effect of the Invention) As described above, the present invention is to tighten the outer cylinder of the cylindrical muffler from the outside by the clamping plate with the heat insulating material interposed therebetween.
The vibration of the muffler can be suppressed without increasing the thickness of the muffler outer cylinder, and the noise of the muffler, in particular, the generation of a shell sound can be prevented. Also, the exhaust muffler is placed on the opposite side of the transmission case with the rear wheel inclining forward and downward, reducing the diameter of the front part of the outer cylinder to a substantially conical shape near the front edge of the fastening plate, and surrounding the heat insulating material. Since the space is divided in the direction and a gap opened in the front-rear direction is formed between the outer cylinder and the fastening plate, the traveling wind smoothly flows into the gap from below the front of the power unit. Therefore, the cooling performance is improved. Further, since a number of small holes facing the gap are formed in the fastening plate, the air in the gap flows out from these small holes. Since the protectors that cover these small holes are attached to the tightening plate via rubber bushes, the protector does not become hot and running air passing between this protector and the tightening plate smoothes out the air flowing out of the small holes. To the rear, and the cooling performance is further improved.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention.
2 is a left side view of a two-wheeled scooter to which the present invention is applied, FIG. 3 is a right side view of the power unit, and FIG. 4 is a development view taken along the line IV-IV in FIG. is there. 76 …… Cylindrical exhaust muffler, 82 …… Outer cylinder, 86 …… Tightening plate, 90 …… Glass wool as heat insulating material, 92 …… Gap, 106 …… Rubber bush, 108 …… Protector, 112 …… Stoma.

Claims (1)

(57) [Claims] 1. A power unit having one rear wheel held at a rear end of a transmission case extending rearward from one side of an engine and a front end pivotally supported by a body frame so as to be vertically swingable, and sandwiching the rear wheel. A scooter-type motorcycle exhaust muffler device having a substantially cylindrical exhaust muffler attached to a power unit, which is located on the opposite side of the transmission case and is inclined forward and downward, wherein a heat insulating material closely adheres to an outer cylinder of the exhaust muffler. And a tubular clamping plate for clamping the outer cylinder from the outside with the heat insulating material interposed therebetween, and reducing the front part of the outer cylinder to a substantially conical shape in front of the vicinity of the front edge of the clamping plate. The heat insulating material is divided in the circumferential direction of the outer cylinder to form a gap between the outer cylinder and the tightening plate that is open in the front-rear direction, and the tightening plate has a number of small holes facing the gap. And protect the small holes from outside with rubber bushing. An exhaust muffler device for a scooter-type motorcycle, wherein the exhaust muffler device is mounted via a through hole.