JP2009264180A - Fastening structure for double duct - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide fastening structure for a double duct 1 capable of securing full sealing performance. <P>SOLUTION: The double duct 1 has one end part 4a of an inside duct 4, insert-formed at a hose flange 2a provided on a first hose 2, and has the other end part 4a insert-formed at a hose flange 3a provided on a second hose 3. An outside duct 6 has one end part 6a jointed to an end surface of the hose flange 2a by laser welding and heat plate welding, and has the other end part 6a jointed to an end surface of the hose flange 3a by laser welding or heat plate welding. Since both the end parts 4a of an inside duct 4 insert-formed at the hose flanges 2a, 3a provided on the first hose 2 and the second hose 3, sections between the first hose 2, the second hose 3, and the inside duct 4 can be sealed airtightly, without having to use fastening parts, such as clamps. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a double duct fastening structure including an inner duct through which air flows and an outer duct disposed outside the inner duct via an air layer.

As a conventional technique, there is a composite duct described in Patent Document 1.
This composite duct is applied to an intake duct of an internal combustion engine, for example, and has a function of reducing noise such as resonance sound and airflow sound caused by intake pulsation, and can transmit sound waves as shown in FIG. It has a tubular flexible thin film member 100, an inner frame 110 disposed on the inner periphery of the flexible thin film member 100, and an outer cylinder 120 that covers the periphery of the flexible thin film member 100. A damper chamber 130 made of an air layer is formed between the conductive thin film member 100 and the outer cylinder 120.
The inner frame 110 is used to support the flexible thin film member 100, and a large number of small holes 111 are formed on the surface. The inner frame 110 has one end fitted to the inner periphery of the first duct 140 connected to the air cleaner side, and the other end of the second duct 150 connected to the intake collector side. It is fitted to the inner periphery, and both ends of the flexible thin film member 100 are sandwiched between the inner frame 110 and the first duct 140 and the second duct 150, and are bonded together in one piece. .
JP 2004-346750 A

However, in the above-described conventional technology, since the flexible thin film member 100 is thin, it is difficult to use the flexible thin film member 100 alone. In other words, the flexible thin film member 100 is insufficient in strength to maintain its own shape. Therefore, the inner frame 110 that is a reinforcing material is disposed on the inner periphery of the flexible thin film member 100, and the inner frame 110. Therefore, it is necessary to maintain the shape of the flexible thin film member 100.
Further, in order to maintain airtightness between the flexible thin film member 100 and the first duct 140 and the second duct 150, the end portion of the inner frame 110 is connected to the first duct 140 and the second duct 150. It is necessary to fit into the inner periphery of the press-fit state. In this case, when the end of the inner frame 110 is press-fitted into the inner periphery of the first duct 140 and the second duct 150, it is assumed that the end of the flexible thin film member 100 is turned up from the inner frame 110. The Therefore, it is difficult to sandwich the end portion of the flexible thin film member 100 between the inner frame 110 and the first duct 140 and the second duct 150, which causes a problem in terms of sealing performance.
The present invention has been made based on the above circumstances, and an object of the present invention is to provide a double duct fastening structure capable of ensuring sufficient sealing performance without using separate parts such as an inner frame.

(Invention of Claim 1)
The present invention is disposed between a first hose arranged upstream in the air flow direction and a second hose arranged downstream in the air flow direction. A double duct fastening structure comprising an inner duct communicating with two hoses and an outer duct disposed on the radially outer side of the inner duct via an air layer, the first hose The second hose is made of an elastic material such as rubber or elastomer, and a hose flange protruding radially outward is provided on the entire circumference at the downstream end of the first hose and the upstream end of the second hose. The double duct is characterized in that the end of the inner duct is insert-molded into the hose flange and the end of the outer duct is joined to the hose flange.

According to said structure, since the edge part of an inner duct is insert-molded by a hose flange, between 1st hose and 2nd hose, and an inner duct, for example, without using fastening parts, such as a clamp, is used. Can be sealed airtight.
Further, by joining the end portion of the outer duct to the hose flange, the first hose and the second hose can be kept at a constant interval via the outer duct. It is not necessary to support the inner duct by using another part such as the inner frame described in the above, and the cost can be reduced by reducing the number of parts.

(Invention of Claim 2)
2. The double duct fastening structure according to claim 1, wherein the inner duct is provided in a flange shape in which an end portion of the hose flange that is insert-molded is bent radially outward with respect to the axial direction of the inner duct. It is characterized by that.
By providing the end portion of the inner duct in a flange shape, it is possible to prevent the end portion of the inner duct from easily coming off from the hose flange.

(Invention of Claim 3)
The double duct fastening structure according to claim 1 or 2, wherein the inner duct is formed to be thinner than the outer duct, and the thickness is set to 0.5 mm or less.
In the double duct of the present invention, the outer duct is thicker than the inner duct, and the end of the outer duct is joined to the hose flange, thereby ensuring the strength of the entire double duct. As a result, it is possible to form the inner duct with a thin film of 0.5 mm or less, and the double duct of the present invention can be used, for example, as a silencer duct that reduces intake noise of an internal combustion engine.

  The best mode for carrying out the present invention will be described in detail with reference to the following examples.

FIG. 1 is a cross-sectional view showing a fastening structure of a double duct 1.
The double duct 1 of the present embodiment is disposed, for example, between an air cleaner of an internal combustion engine and a throttle body, forms a part of an intake passage, and is used as a silencer duct that reduces intake noise of the internal combustion engine. It is done.
As shown in FIG. 1, the double duct 1 includes an inner duct 4 that communicates between a first hose 2 connected to the outlet of the air cleaner and a second hose 3 connected to the inlet of the throttle body. The outer duct 6 is disposed on the radially outer side of the inner duct 4 via the air layer 5.

The first hose 2 and the second hose 3 are each formed in a cylindrical shape by an elastic material such as rubber or elastomer, and at the downstream end of the first hose 2 and the upstream end of the second hose 3, Hose flanges 2a and 3a protruding outward in the radial direction are provided.
The inner duct 4 is made of, for example, a resin and has a circular cross-sectional shape, that is, a cylindrical shape as a whole. Both end portions 4a of the inner duct 4 are provided in a flange shape that bends radially outward. The inner duct 4 is formed thinner than the outer duct 6, and is set to, for example, 0.5 mm or less, preferably 0.25 mm.

The outer duct 6 is made of, for example, a resin and has a circular cross section like the inner duct 4, and has an inner diameter larger than the outer diameter of the inner duct 4. Both end portions 6a of the outer duct 6 are bent inwardly in the shape of an L-shape inward in the radial direction, and an air layer is formed between the outer peripheral surface of the inner duct 4 and the inner peripheral surface of the outer duct 6 by the bent height. 5 is formed. The wall thickness of the outer duct 6 is set to 2 to 3 mm, for example.
As shown in FIG. 1, in the double duct 1, one end 4 a of the inner duct 4 is insert-molded into a hose flange 2 a provided in the first hose 2, and the other end 4 a The hose flange 3 a provided in the second hose 3 is insert-molded. The outer duct 6 has one end 6a joined to the end face of the hose flange 2a by laser welding or hot plate welding, and the other end 6a joined to the end face of the hose flange 3a by laser welding or hot plate welding. ing.

According to said structure, since the both ends 4a of the inner duct 4 are insert-molded in the hose flanges 2a and 3a provided in the 1st hose 2 and the 2nd hose 3, for example, fastening parts, such as a clamp, are used. Without being used, the space between the first hose 2 and the second hose 3 and the inner duct 4 can be hermetically sealed. In addition, since the edge part 4a of the inner duct 4 is provided in the flange shape bent to a radial direction outer side, the edge part 4a of the inner duct 4 does not come off easily from the hose flanges 2a and 3a.
Further, by joining the end portion 6a of the outer duct 6 bent into an L-shaped cross section to the hose flanges 2a and 3a, the gap between the first hose 2 and the second hose 3 is interposed via the outer duct 6. Can be kept at regular intervals. As a result, for example, it is not necessary to support the inner duct 4 using another part such as an inner frame described in Patent Document 1, and the cost can be reduced by reducing the number of parts.

It is sectional drawing which shows the fastening structure of a double duct (Example 1). It is sectional drawing which shows the fastening structure of a double duct (prior art).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Double duct 2 1st hose 2a Hose flange of 1st hose 3 2nd hose 3a Hose flange of 2nd hose 4 Inner duct 4a End part of inner duct 5 Air layer 6 Outer duct 6a End of outer duct Part

Claims (3)

The first hose and the second hose are arranged between a first hose arranged upstream in the air flow direction and a second hose arranged downstream in the air flow direction. A fastening structure of a double duct composed of an inner duct communicating with a hose and an outer duct arranged via an air layer on the radially outer side of the inner duct,
The first hose and the second hose are each formed of an elastic material such as rubber or elastomer, and project radially outward from the downstream end of the first hose and the upstream end of the second hose. A hose flange is provided around the entire circumference.
The double duct has a double duct fastening structure, wherein an end of the inner duct is insert-molded to the hose flange, and an end of the outer duct is joined to the hose flange. In the double duct fastening structure according to claim 1,
The double duct fastening structure, wherein the inner duct is provided in a flange shape in which an end part insert-molded on the hose flange is bent radially outward with respect to the axial direction of the inner duct. . In the double duct fastening structure according to claim 1 or 2,
The double duct fastening structure, wherein the inner duct is formed thinner than the outer duct, and the thickness is set to 0.5 mm or less.

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