JPS5953230A - Exhaust pipe device for motorcycles - Google Patents

Abstract

PURPOSE:To achieve sufficient exhaust tube length thus to exhibit the engine performance effectively by passing an exhaust tube to be coupled to the rear cylinder of a front/rear V-type internal combustion engine at the side of a rear cylinder then bending rearward. CONSTITUTION:In a V-type internal combustion engine E where front and rear cylinder blocks 1f, 1r are arranged in V-shape in front and rear direction of a car, an exhaust tube 8f to be coupled to the exhaust port 4f of the front cylinder block 1f will pass below the front face of said block 3f and bend rearward. While an exhaust tube 8r to be coupled to the exhaust port 4r of the rear cylinder block 1r will pass obliquely below the left side face while bending from the back face of said block 1r toward the left side face then bend rearward to be coupled to an exhaust muffler 10. Here the exhaust tube 8r is fixed with a heat shielding board 15 to cover the outside face containing the surface facing with an ignition plug 7r.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a motorcycle, in particular a V-type internal combustion engine having a front cylinder block and a rear cylinder block arranged in a V-shape in the front-rear direction of the vehicle, mounted on a body frame. The present invention relates to an exhaust pipe device for a motorcycle in which a spark plug is arranged on the side surface of the block and exhaust ports are opened on the front surface of the front cylinder block and the rear surface of the rear cylinder block.

Generally, in this type of motorcycle, the exhaust port of the rear cylinder block is relatively close to the exhaust muffler located at the rear lower part of the vehicle, so if they are connected with an exhaust pipe with less bend, There is a problem in that the length of the exhaust pipe is insufficient and the desired output performance cannot be achieved, especially when the engine is operating at low speeds.

Therefore, in the present invention, the exhaust pipe connected to the exhaust port of the rear cylinder block is arranged so that it passes through the side surface of the rear cylinder block and is bent rearward, so that the exhaust pipe of the rear cylinder block has a sufficient length. A first object of the present invention is to provide the above-mentioned exhaust pipe device which provides the engine with the desired performance.

By the way, when the exhaust pipe of the rear cylinder block is arranged as described above, the exhaust pipe passes near the ignition plug on the side of the rear cylinder block, so the radiant heat of the exhaust pipe affects the ignition plug, causing the ignition plug to This causes the inconvenience of accelerating deterioration to some extent.

Therefore, a first object of the present invention is to provide the exhaust pipe device in which a heat shield plate is attached to the outer peripheral surface of the exhaust pipe facing the ignition plug so that the radiant heat of the exhaust pipe does not affect the ignition plug. 2 objectives.

An embodiment of the present invention will be described below with reference to the drawings. In Fig. 1, a body frame F of a motorcycle includes:
A V-type internal combustion engine E is mounted between the front and rear wheels Wf and lVr. This internal combustion engine E has a front cylinder block 1f and a rear cylinder block 1r arranged in a V-shape in the longitudinal direction of the vehicle, and a common crankcase 2 connected to the base ends of these blocks. block 1
The intake boat 3f and exhaust port 4f of the rear cylinder block 1r are opened at the rear and front sides thereof, and the intake boat 3r and exhaust port 4r of the rear cylinder block 1r are opened at the front and rear sides of the rear cylinder block 1r. The carburetors 5f, 5γ that supply the two cylinder blocks 1f, 11-
It is arranged in a V-shaped space 6 between them.

Furthermore, spark plugs 7f and 7r are mounted on the left and right side surfaces of each cylinder block 1f and 1r, respectively.

Exhaust boats 4f and 47- have front and rear exhaust pipes 8f,
8r are connected to each other, and the front exhaust pipe 8f is arranged so as to pass downward through the front surface of the front cylinder block 1f and bend rearward, as usual in the past. Exhaust muffler to be placed (not shown)
The rear exhaust pipe 8r is connected to the rear cylinder block 1.
It is arranged so that it bends from the back of γ toward the left side, passes diagonally downward on the left side, then largely detours around the left step 9 and bends backward, and then the vehicle body frame F
It is connected to an exhaust muffler 10 located at the lower left side of the exhaust muffler 10.

As shown in FIG. 2, the rear exhaust pipe 8r is composed of a single pipe 11 and a double pipe 12, and the double pipe 11 is the exhaust port 4r.
The double pipe 12 is arranged in an upper section starting from the opening of the rear cylinder block 1r and ending halfway on the left side of the rear cylinder block 1r, and the double pipe 12 is arranged in a lower section starting from the end of the single pipe 11 and ending at the front end of the exhaust muffler 10. Ru. Although the upper section has a relatively steep bend, the single pipe 11, which is easy to bend, can be easily installed in this section, and the lower section has a relatively steep bend.
- Since the curved portion is relatively gentle, even the double pipe 12, which is difficult to bend, can be easily installed in this section.

The inner tube 12α and the outer tube 12A of the double tube 12 fit together with a heat insulating gap 13 in between except for both ends, and the ends are tightly coupled to each other. The lower end of the single pipe 11 is fitted into the upper end of the double pipe 12, and then the two are welded 14.

After this welding, the double pipe 11 and the double pipe 12, that is, the entire rear exhaust pipe 8r is plated.

As shown in FIGS. 1 to 5, a heat shield plate 15 is attached to the heavy pipe 11 in the following manner to cover the outer surface including the surface facing the ignition plug 7r.

The heat shield plate 15 has a semicircular cross section, and two first bands 16 are fixed to the inner surface of the heat shield plate 15 via a porous spacer plate 17. The spacing plate 17 forms a certain heat insulation gap 18 between the first band 161 and the heat shield plate 15, and the spacer plate 17 forms a certain insulation gap 18 between the first band 161 and the heat shield plate 15.
A plurality of convex portions 19.
It has 20. A second band 16 □ is hook-coupled 21 to one end of the first band 161, and the first and second bands 16
．． ．． These connecting end pieces 16a and 16A are connected by bolts 22 and nuts 23 so as to work together to tighten the outer peripheral surface of the single pipe 11. At this time, in order to position the heat shield plate 15, one set of bands 16. ．． The connecting end pieces 16a and 16A of 162 are also connected to the heavy pipe 11 with a positioning protrusion 24 protruding from the outer circumferential surface of the pipe 11 interposed therebetween.

An oval decorative ring 25 is attached to the outer surface of the heat shield plate 15.

The heat shield plate 15 arranged to partition between the ignition plug 7r and the rear exhaust pipe 8r blocks the radiant heat of the rear exhaust pipe 8r to prevent it from affecting the ignition plug 7r, and also serves as a shield. hot plate 15
Since the double pipe 11 also covers the outer surface of the single pipe 11, even if the outer surface of the double pipe 11 becomes discolored due to overheating due to exhaust heat, the appearance will not be damaged.

On the other hand, since the double tube 12 has a heat shielding gap 13 between the inner and outer tubes 12a and 116, the outer tube 1275 will not be overheated, and therefore discoloration due to overheating will not appear on its outer surface. do not have.

Further, as shown in FIGS. 6 to 8, a decorative plate 26 is attached to the rear end of the double pipe 12 and the front end of the exhaust muffler 10 in the following manner to cover especially the connecting portions thereof.

The decorative plate 26 has an arcuate cross section along the top and side surfaces of the double pipe 12 and the exhaust muffler 10, and has two first bands 27. are fixed via spacer pieces 28. A second band 27□ is coupled to one end of the first band 27, respectively, and these first and second bands 27. ．． These connecting end pieces 27α and 27h are connected to the bolt 3 so that the connecting end pieces 27□ work together to tighten the outer peripheral surface of the double pipe 12.
0 and a nut 31. At that time, decorative board 2
6, one set of bands 271°27
2 connecting end pieces 27 (1, 27b are connected to the double pipe 12 with a positioning protrusion 32 protruding from the outer circumferential surface of the double pipe 12 sandwiched therebetween. Hole 3
A support plate 34 forming the exhaust muffler 10 is fixed, and a locking pawl 35 that engages with the support hole 33 is fixed to the outer peripheral surface of the exhaust muffler 10. Therefore, the decorative plate 26 is connected to the locking claw 35 and the band 16. ．． 16□ to be installed in place.

As described above, according to the present invention, the exhaust pipe connected to the exhaust port of the rear cylinder block is arranged so as to pass through the side surface of the rear cylinder block and bend rearward. Even if the distance between the port and the exhaust muffler is short, the exhaust pipe can be given sufficient length to allow the engine to exhibit the desired performance, and the exhaust pipe can pass through a wide area on the side of the engine. The engine is cooled well by the wind flowing around the sides of the engine, further improving engine performance.

In addition, a heat shield plate is attached to the outer peripheral surface of the exhaust pipe facing the ignition plug located on the side of the rear cylinder block, which prevents the radiant heat of the exhaust pipe from affecting the ignition plug. Early deterioration due to overheating can be prevented.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a side view of a motorcycle, FIG. 2 is a partial vertical side view showing the upper part of the exhaust pipe of the motorcycle with the heat shield removed, and FIG. 3 is a side view of the motorcycle. A side view similar to FIG. 2 with the heat shield plate attached, FIG. 4 is a plan view thereof, FIG. 5 is an enlarged sectional view taken along the line V-V in FIG.
The figure is a partial vertical sectional side view of the vicinity of the connection between the exhaust pipe and the exhaust muffler 10, and FIGS. 7 and 8 are sectional views taken along the lines 1--2 and 11--1 in FIG. E...Internal combustion engine, F...Vehicle frame, 1. f, 1
γ...front and rear cylinder blocks, 4r...exhaust boat, 7r...spark plug, 8r...exhaust pipe, 10...
・Exhaust muffler, 15...Heat shield plate Patent applicant Honda Motor Co., Ltd. JP 59-53230 (6) Commissioner of the Japan Patent Office 1. Indication of the case 1982 Patent Application No. 163691 2 Title of the invention Exhaust pipe device for motorcycles 3, person making the amendment Relationship to the case Patent applicant name (532) Honda Motor Co., Ltd. 4, representative
Director 105 Address No. 1 Nijimura Building 5, 4-4-5 Shinbashi, Minato-ku, Tokyo Subject of amendment 178-

Claims (1)

[Claims] A V-type internal combustion engine is mounted on the vehicle body frame, and has a front cylinder block and a rear cylinder block arranged in a V-shape in the longitudinal direction of the vehicle, and a spark plug is arranged on the side of each cylinder block, and a spark plug is arranged on the side of each cylinder block. and a motorcycle in which exhaust ports are opened at the rear of the rear cylinder block, and an exhaust pipe connected to the exhaust port of the rear cylinder block is arranged so that the exhaust pipe passes through a side surface of the rear cylinder block and is bent rearward. An exhaust pipe device for a motorcycle, wherein a heat shield plate is attached to an outer peripheral surface of the exhaust pipe facing the ignition plug.