JPH0527225U - Scarf - Google Patents

Abstract

(57) [Summary] [Purpose] Use a stainless steel pipe to improve durability against rust. [Structure] An inner cylinder 1 made of a stainless steel pipe having a uniform outer diameter L and a large number of small holes 2, an inner diameter P larger than the outer diameter L of the inner cylinder 1, and both end portions 3a, 3b. An outer cylinder 3 made of a stainless steel pipe having a reduced diameter and an inner diameter Q substantially matching the outer diameter L of the inner cylinder 1, and an outer diameter R smaller than the inner diameter M of the inner cylinder 1 are connected to the inner cylinder 1. The exhaust pipe 4 is made of a stainless steel pipe whose end 4a is expanded so that its outer diameter S substantially matches the inner diameter M of the inner cylinder 1, and the inner cylinder 1 is inserted into the outer cylinder 3 and The expanded end 4a of the exhaust pipe 4 is connected to the inner cylinder 1
It is configured by being inserted into the end portion 1a and joined.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a muffler used in connection with an internal combustion engine, especially an internal combustion engine for automobiles.

[0002]

[Prior Art]

 Conventionally, this type of muffler includes an outer cylinder having a reduced diameter at both ends and a muffler pipe (inner cylinder) having a large number of small holes as described in, for example, Japanese Utility Model Publication No. 54-108840. It is composed of. Since both ends of the outer cylinder are reduced in diameter, they are generally manufactured using an iron pipe having good workability, particularly good malleability.

Normally, in the muffler, the outer cylinder, the diameter of the exhaust pipe, and the like can be changed according to the exhaust capacity of the connected engine. Therefore, both ends of the outer cylinder to be reduced in diameter need to be formed by drawing with a considerably large reduction in diameter depending on the engine to be connected.

[0004]

[Problems to be solved by the device]

 However, in the case of a muffler made of iron pipe, the exhaust gas from the engine contains a large amount of water, so if it is used for a long period of time, it will rust inside and cause holes in the outer cylinder. There was a risk that it would not function as a perforated muffler. On the other hand, stainless steel has recently been in the spotlight as a material that is unlikely to rust, but since stainless steel has poorer malleability than iron, it was difficult to use it as a muffler material of this type of structure.

The present invention aims to solve such a problem.

[0006]

[Means for Solving the Problems]

 The present invention has taken the following means in order to achieve such an object. That is, the muffler according to the present invention has an inner cylinder made of a stainless steel pipe having a uniform outer diameter and a large number of small holes, an inner diameter larger than the outer diameter of the inner cylinder, and both ends thereof. The outer cylinder made of stainless steel pipe whose diameter is reduced and its inner diameter is approximately equal to the outer diameter of the inner cylinder, and the end which has an outer diameter smaller than the inner diameter of the inner cylinder and is connected to the inner cylinder are expanded and The exhaust pipe is made of a stainless steel pipe whose outer diameter is substantially equal to the inner diameter of the inner cylinder. It is characterized by being inserted and joined.

[0007]

[Action]

 With such a configuration, both ends of the outer cylinder are processed to reduce the diameter based on the outer and inner diameters of the inner cylinder, and the ends of the exhaust pipe are processed to expand the outer cylinder. It is not necessary to process only one with a high reduction rate, and it is possible to manufacture an outer cylinder by processing a stainless pipe within the limits of the malleability of stainless steel. Therefore, the inner cylinder, the outer cylinder, and the exhaust pipe can be reasonably joined to each other without applying unreasonable internal stress to the material forming the muffler.

[0008]

【Example】

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

FIG. 1 is a vertical cross-sectional view showing the structure of an embodiment of the present invention. In the figure, reference numeral 1 denotes an inner cylinder, in which a large number of small holes 2 are formed in a stainless pipe, and both ends 3a and 3b are inserted in an outer cylinder 3 made of a stainless pipe having a reduced diameter. An exhaust pipe 4 made of a stainless steel pipe having an enlarged diameter is inserted into both ends 1a and 1b of the inner cylinder 1 and joined by welding. The material of the inner cylinder 1, the outer cylinder 3 and the exhaust pipe 4 is, for example, SUS409L-E having a plate thickness of 1.2 mm.

The inner cylinder 1 is the same as the raw material except that the small hole 2 is provided, that is, the center portion and both end portions have the same outer diameter L and inner diameter M. The small hole 2 is bored almost all over the inner cylinder 1, but since both ends overlap the ends 3a and 3b of the outer cylinder 3, it is not necessary to provide the small hole 2. The inner diameter of the inner cylinder 1 is larger than the outer diameter R of the material of the exhaust pipe 4 connected thereto.

On the other hand, in the outer cylinder 3, the inner diameter P of the central portion 3 c is larger than the outer diameter L of the inner cylinder 1, and the inner diameters Q of both ends substantially match the outer diameter L of the inner cylinder 1. That is, the outer cylinder 3 has a diameter reduced by processing both ends of a stainless steel pipe having an inner diameter that matches the inner diameter P of the central portion 3c. The diameter reduction ratio of both end portions 3a and 3b, that is, the reduced diameter with respect to the outer diameter before the diameter reduction (outer diameter of the central portion 3c) {= (outer diameter of the central portion 3c)-(outer diameter of the end portion 3a) } (Reduction rate) is preferably about 27 to 30%. In this case, the angle θ formed by the tapered portion formed between the central portion 3c and the end portions 3a and 3b of the outer cylinder 3 with the horizontal is 15 °. Further, the length of the outer cylinder 3 is slightly shorter than that of the inner cylinder 1, and the entire circumferences of both ends a and 3b of the outer cylinder 3 are dimensioned to be welded to the outer peripheral surface of the inner cylinder 1.

The exhaust pipe 4 is formed by expanding an end portion 4 a of a stainless steel pipe having an outer diameter R smaller than the inner diameter M of the inner cylinder 1 so that the outer diameter S thereof substantially matches the inner diameter M of the inner cylinder 1. Manufactured. In this case, the diameter expansion ratio of the end 4a, that is, the ratio of the expanded diameter {= (outer diameter R)-(outer diameter of the end 4a)} to the outer diameter (outer diameter R) before the diameter expansion (diameter expansion ) Is preferably about 20%. As an example, the dimensions of each part of the inner cylinder 1, the outer cylinder 3 and the exhaust pipe 4 are described below.

The inner diameter M of the inner cylinder 1 is 46.3 mm, the outer diameter L of the inner cylinder 1 is 47.5 mm, the outer diameter of the outer cylinder 3 is 70 mm, the inner diameter Q of the end of the outer cylinder 3 is 48.7 mm, and the outer diameter of the exhaust pipe 4 is Diameter R 38. 1 mm, outer diameter S of the end of the exhaust pipe 4 S 45.7 mm, plate thickness of the inner cylinder 1, the outer cylinder 3 and the exhaust pipe 4 1.2 mm, diameter reduction ratio of the outer cylinder 3 27%, expansion of the exhaust pipe 4 Rate 20%.

The inner cylinder 1, the outer cylinder 3 and the exhaust pipe 4 which are respectively processed as described above are assembled as a muffler as described below.

First, the inner cylinder 1 having the small holes 2 formed therein is inserted into the outer cylinder 3. The inner cylinder 1 is temporarily fixed at a predetermined position in the outer cylinder 3, and the edges of both ends 3a and 3b of the outer cylinder 3 are welded to the outer surface of the inner cylinder 1 over the entire circumference. Next, the expanded end portions 4a of the exhaust pipe 4 are inserted into both ends of the inner cylinder 1, and the edges of the end portion of the inner cylinder 1 are welded to the outer surface of the exhaust pipe 4 over the entire circumference. The invention of the present application is not limited to the embodiments described above. Although not used in the above embodiment, a space formed between the inner cylinder 1 and the outer cylinder 3 may be filled with a sound absorbing material such as glass wool.

Besides, the configuration of each part is not limited to the illustrated example, and various modifications can be made without departing from the spirit of the present invention.

[0017]

[Effect of the device]

 As described above, according to the present invention, both ends of the outer cylinder are reduced in diameter and the ends of the exhaust pipe connected to the inner cylinder are enlarged, so that only the outer cylinder is extremely reduced in diameter. Since it is not processed, the inner cylinder, the outer cylinder and the exhaust pipe can be joined smoothly and the durability can be improved.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention.

[Explanation of Codes] 1 ... Inner cylinder 1a ... End part of inner cylinder 1 ... Small hole 3 ... Outer cylinder 3a, 3b ... End part of outer cylinder 3 ... Exhaust pipe 4a End part of exhaust pipe 4 L ... Inner cylinder 1 outer diameter M ... inner cylinder 1 inner diameter P ... outer cylinder 3 inner diameter Q ... outer cylinder 3 end inner diameter R ... exhaust pipe 4 outer diameter S ... exhaust pipe 4 end outer diameter

Claims (1)

[Scope of utility model registration request] 1. An inner cylinder made of a stainless steel pipe having a uniform outer diameter and a large number of small holes, and an inner diameter larger than the outer diameter of the inner cylinder, and both ends thereof having a reduced inner diameter. Is an outer cylinder made of stainless steel pipe whose outer diameter is approximately the same as the inner cylinder,
An exhaust pipe made of a stainless steel pipe having an outer diameter smaller than the inner diameter of the inner cylinder and an end portion connected to the inner cylinder being expanded and having an outer diameter substantially matching the inner diameter of the inner cylinder, A muffler characterized in that an inner cylinder is inserted into an outer cylinder, and a diameter-expanded end portion of an exhaust pipe is inserted into and joined to an inner cylinder end portion.