JPS60119313A - Muffler for engine - Google Patents

Abstract

PURPOSE:To aim at making a muffling effect ever so better as well as improving a cooling effect against exhaust gas, by inserting a partition plate provided with each of interconnecting holes, concaving its outer circumferential part inward, into a muffler pipe and thereby partitioning it into plural muffling chambers, while covering an outer side of the muffler pipe with a cooling pipe with some clearance made up in between, and feeding cooling air from the front end side through the tail pipe side. CONSTITUTION:In this muffler pipe 1, an exhaust pipe 2 is coupled to the front end while a muffler tail pipe 8 to the rear end, respectively, and the inside of the muffler pipe 1 is partitioned into plural muffling chambers 7 by means of partition pieces 6 coupling partition plates 5 to each pipe body 4 installing each of interconnecting holes being concaved inward in its outer circumferential part. The muffler pipe 1 is covered with a cooling pipe 10 with a clearance 9 at the outer side. The cooling pipe 10 has an air leading hole 11 at its front end, while its rear end is welded to the muffler tail pipe 8 on which an exhaust air hole 12 is bored.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a muffler for an engine mounted on a motorcycle, etc., which has been improved to have a high cooling effect and a high silencing effect.

Engines mounted on motorcycles generally use long cylindrical mufflers. This muffler cannot be freely adjusted in outer diameter and length due to the location where it is installed, and is manufactured within regulated dimensions, so that the muffler may not have sufficient silencing effect due to the expansion of exhaust gas. The inside of the muffler tube is usually partitioned into a plurality of silencing chambers by a partition plate, and each silencing chamber is communicated with each other by a communicating pipe set up on the partition plate. For this reason, the exhaust gas rarely comes into contact with the muffler tube, and thermal energy is not absorbed sufficiently, resulting in high-temperature exhaust gas being released.

In view of these points, the present invention has been improved to have good absorption of thermal energy, good cooling performance, and high silencing effect.Hereinafter, embodiments of the present invention will be described as shown in the drawings.

The muffler tube 1 has an exhaust pipe 2 connected to its front end, and is formed into a wide cylindrical shape. The muffler tube 1 may be shaped like a tea caddy. A plurality of muffler chambers 7 are partitioned by inserting into the muffler tube 1 a partition piece 6 in which a partition plate 5 is connected to a tube body 4 having a communication hole 3 recessed inward on its outer periphery. A muffler tail pipe 8 is provided protruding from the rear end. The muffler tube 1 is covered with a cooling tube lO with a gap 9 provided on the outside. The cooling cylinder 10 is provided with air guide holes 11 at the front end. Further, the rear end of the cooling cylinder 10 is welded to a protruding muffler tail pipe 8, and an exhaust hole 12 is bored in the muffler tail pipe 8.

Exhaust gas entering the muffler tube 1 from the exhaust pipe 2 expands in the muffler tube 1, passes through the muffler chamber 7, then passes through the muffler L, passes through the communication hole 3, enters the next muffler chamber 7, and expands further. to mute the sound. This process is repeated from step 1 to finally discharged through the muffler tail pipe 8. The cooling air flows from the air guide hole (1) through the gap 9 between the cooling tube 10 and the muffler tube 1, flows to the exhaust hole 12 of the muffler tail tube 8, and is discharged from the muffler tail tube 8 together with the exhaust gas.

Since the cooling air is sucked out to the exhaust hole 12 at the flow rate of the exhaust gas flowing through the muffler tail pipe 8, a cooling air flow is created in the gap 9.

When the exhaust gas passes through the communication hole 3, it comes into contact with the muffler tube 1, so cooling is promoted and thermal energy is absorbed well. The ratio of the cross-sectional area of the silencing chamber 7 and the cross-sectional area of the communication hole 3 is large, so the silencing effect is high, and the resistance of the inner pipe is small, so that the silencing effect can be enhanced with a limited length.

As explained above, the present invention inserts a partition piece having a communication hole recessed inward on the outer periphery into a cylindrical muffler tube to partition it into a plurality of silencing chambers, and creates a gap between the outside of the muffler tube. Since the cooling cylinder is covered with a cooling cylinder, an air guide hole is provided at the front end of the cooling cylinder, and an exhaust hole is provided in the muffler tail pipe, the cooling air is sucked out at the flow rate of the exhaust gas flow, and the cooling air flows into the gap outside the muffler cylinder. This allows the exhaust gas to come into contact with the muffler tube as it passes through the communication hole, allowing better absorption of thermal energy and better cooling. Furthermore, the ratio of the cross-sectional area of the muffling chamber to the cross-sectional area of the communication hole can be made large, and the resistance of the inner pipe is small, so that the muffling effect can be enhanced with a limited size.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a longitudinal cross-sectional view and FIG. 2 is a cross-sectional view taken along the line A--A in FIG. 1. 1...Muffler tube, 3...Communication hole, 6...Partition piece, 7
...Muffler chamber, 8...Muffler tail pipe, 9...Gap, 1
0... Cooling tube, 11... Air guide hole, 12... Air exhaust hole. Applicant's agent Kiyoshi Inomata

Claims (1)

[Claims] A partition piece with a communication hole recessed inward on the outer periphery is inserted into a cylindrical muffler tube to partition it into multiple silencing chambers, and the outside of the muffler tube is covered with a cooling tube with a gap, and the front end of the cooling tube is An engine muffler characterized in that an air guide hole is provided in the muffler tail pipe, and an air exhaust hole is provided in the muffler tail pipe.