JP2004132448A - Pipe connecting structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connecting structure for piping capable of securing a sufficiently large pulling-out strength and sealing performance with a simple constitution. <P>SOLUTION: This pipe connecting structure has a cylindrical connecting member 11 composed of an elastic material having a first connecting part 11 connected to a pipe P and a second connecting part 12 connected to the inner peripheral surface side of a resin tube 30 and a cylindrical sleeve 20 arranged on an inner peripheral surface of the second connecting part 12 of this connecting member and having an outer diameter larger than an inner diameter of the connecting member 11. The resin tube 30 has a circular tubular connecting end part 31, a first engaging object part 32a for engaging with an engaging part 13 arranged on the outer periphery of the second connecting part 12 of the connecting member and a second engaging object part 33a for engaging with a sleeve engaging part 23 arranged on the outer periphery of the sleeve. The second connecting part 12 of the connecting member is held between the sleeve 20 and the connecting end part 31 of the resin tube in a compressed state. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a pipe connection structure for connecting a metal pipe used for a fuel pipe or a water pipe for an automobile and a resin tube.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a metal pipe and a rubber hose have been used as a pipe for an automobile, and a metal clamp has been used to connect the two. In recent years, resin tubes have been increasingly used in place of rubber hoses in order to respond to needs for cost reduction and weight reduction, and connectors that are excellent in assembly workability are commonly used to connect metal pipes and resin tubes. Have been.
[0003]
However, in the connection using the conventional connector, although the workability at the time of assembling is certainly improved, the molding of the connector main body, the assembly of the elastic ring member, and the press-fitting to the resin tube are required, and the cost is reduced. Had to be high.
[0004]
As another connection structure for a resin tube, for example, one described in JP-A-2002-89762 is known. That is, as shown in FIG. 5, the metal pipe 130 and the resin tube 140 are fixed to both ends of the connecting member 120 made of an elastomer. The resin tube 140 has an annular projection 142 on the outer peripheral surface of the connection end 141, and is fixed to the connection member 120 by press-fitting or vulcanization bonding without using a fastening member.
[0005]
However, in such a conventional connection structure, there is no clamp on the outer peripheral surface of the elastomeric connection member 120, so that the diameter of the connection member 120 can be freely increased. Therefore, when a large pulling force is applied, the annular protrusion 142 formed on the outer peripheral surface of the connection end 141 moves while pressing and expanding the connection member 120, and is easily disconnected, and sufficient pulling strength is obtained. There was a problem that can not be.
[0006]
In addition, although the pull-out property can be improved by the adhesive, the pull-out strength is inevitably reduced due to deterioration or aging due to the fluid flowing inside, and the reliability is low and the cost is increased due to the additional bonding step. there were.
[0007]
[Patent Document 1]
JP-A-2002-89762
[Problems to be solved by the invention]
An object of the present invention is to solve the above-described problems of the conventional technology, and an object of the present invention is to provide a connection structure for piping that can ensure sufficiently high pull-out strength and sealing performance with a simple configuration.
[0009]
[Means for Solving the Problems and Their Functions and Effects]
A pipe connection structure provided by the present invention to solve the above-mentioned problem has an elasticity including a first connection portion connected to a pipe and a second connection portion connected to an inner peripheral surface side of a resin tube. A cylindrical connecting member made of a material, and a cylindrical sleeve disposed on the inner peripheral surface of the second connecting portion of the connecting member and having an outer diameter larger than the inner diameter of the connecting member; A first engaged portion engaged with an engaging portion provided on an outer periphery of a second connecting portion of the connecting member; and a second engaged portion engaged with an engaging portion provided on an outer periphery of the sleeve. Wherein the second connecting portion of the connecting member is held in a compressed state between the connecting end of the sleeve and the resin tube.
[0010]
In the connection structure according to the present invention, when connecting the pipe and the resin tube, a sufficient sealing property is obtained because the connection member made of an elastic material is tightly held in a compressed state by the resin tube and the rigid sleeve. Can be Further, since the connection member and the sleeve are mechanically engaged with the inner peripheral portion of the resin tube, sufficient pull-out strength can be obtained.
[0011]
In the connection structure, the resin tube may include a cylindrical opening end and a bellows portion, and the first and second engaged portions may be formed in the bellows portion. Accordingly, since it is not necessary to separately provide the first and second engaged portions, the structure of the resin tube is simplified, and the manufacture is facilitated.
[0012]
Further, an annular projection may be formed on the outer periphery of the rear end of the sleeve or on the inner periphery of the connection end of the tube. Thereby, the sealing performance at the second connection portion of the connection member is further improved.
[0013]
The second connecting portion includes an annular protrusion formed at an end of the connection member, and a notch is formed in the protrusion in the axial direction, so that the protrusion is elastically deformed at the time of press-fitting. Since press-fitting is more likely to occur, press-fitting workability is further improved.
Preferred embodiments of the present invention will be described below to further clarify the configuration and operation of the present invention described above.
[0014]
FIG. 1 is a side view showing a cross section of an upper half of a connection structure according to an embodiment of the present invention, and FIG. 2 is an exploded cross-sectional view of each component. This connection structure is used for fuel system piping and water system piping of an automobile. The configuration of each unit will be described with reference to FIG.
[0015]
(1) Pipe P
The pipe P is formed of metal or resin, and a bead Pa for retaining the connection member 10 is formed in a ring shape.
[0016]
(2) Connection member 10
The connection member 10 includes a first connection portion 11 connected to a pipe, and a second connection portion 12 connected to the inner peripheral surface side of the resin tube.
[0017]
The connection member 10 has a cylindrical shape, and an engagement portion 13 is formed on an outer peripheral surface of an end portion of the second connection portion 12 to prevent the resin tube 30 from coming off. The engagement portion 13 is formed in an annular shape at the end of the connection member 10 on the side of the second connection portion 12, and has an inclined surface 15 whose diameter decreases toward the distal end on its end surface. Further, a step portion 14 is formed in the engaging portion 13 on the opposite side of the inclined surface 15 (see FIG. 1).
[0018]
The connection member 10 is made of an elastic material, for example, a rubber material such as ethylene-propylene rubber (EPDM), nitrile rubber (NBR), a polymer blend of nitrile rubber and vinyl chloride (NBR / PVC), an olefin-based thermoplastic elastomer, or styrene. It is made of a thermoplastic elastomer. The type of material may be appropriately selected according to the liquid to be transported.
[0019]
(3) Sleeve 20
The sleeve 20 has a cylindrical shape, and a sleeve engaging portion 23 is formed on an outer peripheral surface of the sleeve 20 to prevent the resin tube 30 from coming off. The sleeve engaging portion 23 is formed so as to protrude annularly at one end of the sleeve cylindrical portion 21, and has an inclined surface 25 whose diameter decreases toward the tip. Further, a step portion 24 is formed on the sleeve engaging portion 23 on the opposite side of the inclined surface 25 (see FIG. 1).
[0020]
The sleeve 20 is formed of a material having rigidity, for example, a resin material such as a metal such as stainless steel (SUS), a nylon resin, or a polyphenylene sulfide resin reinforced with glass fiber.
[0021]
(4) Resin tube 30
The resin tube 30 includes a tubular connection end portion 31 and a bellows portion (32, 33, 34), and an inner peripheral portion of a first peak portion 32 of the bellows portion adjacent to the connection end portion 31 is first engaged. The second peak portion 33 functions as a second engaged portion 33a.
The first peak 32 is formed to be larger in diameter than the second peak 32.
The resin tube 30 is formed of a resin material having resistance to a liquid to be transported. In the case of a fuel system pipe, for example, it can be formed in a single layer or a multilayer using a polyamide resin such as 12 nylon, 6 nylon, 66 nylon, or a polyethylene resin.
[0022]
The resin tube 30 can be formed continuously with different cross-sectional shapes at the bellows (32, 33, 34) and the connection end 31 using a corrugator mechanism. That is, after the resin tube is extruded by the extruder, a molding unit having a molding surface following the bellows (32, 33, 34) and the connection end 31 is conveyed in a loop to connect to the end. The resin tube 30 having the end portion 31 and the bellows portions (32, 33, 34) having different mountain diameters can be manufactured.
[0023]
(5) Connection work of the connection member 10 In order to connect the connection member 10 to the resin tube 30, the connection member 10 is pressed into the connection end 31 of the resin tube 30 from the engagement portion 13 side. At this time, the connecting member 10 is inserted in a state where the outer diameter thereof is reduced by being smoothly elastically deformed by the inclined surface 15. When the engaging portion 13 is press-fitted to a position where it reaches the first peak portion 32 of the resin tube 30, the engaging portion 13 is elastically restored, and the step portion 14 is engaged with the first engaged portion 32a and fixed. Is done.
[0024]
At this time, by setting the hypotenuse of the first peak portion 33 to 70 ° to 90 °, preferably 80 ° to 90 ° with respect to the axis of the resin tube 30, the step portion 14 and the first engaged portion 32a can be connected to each other. Engagement becomes more reliable and the pull-out strength of the resin tube 30 can be increased. A cylindrical portion 34 having a smaller diameter than the connection end portion 31 is formed between the first peak portion 33 and the second peak portion 34, and the engaging portion 13 is connected to the first peak portion 32 of the resin tube 30 at the time of press fitting. Is prevented from being exceeded, and is reliably stopped at the engagement position. In this case, the outer diameter of the second connecting portion 12 of the connecting member is set slightly larger than the inner diameter of the connecting end portion 31 of the resin tube 30 so that the second connecting portion 12 can be compressed by press-fitting the sleeve 20 described later. The amount can be increased. Further, by applying a lubricant to the outer surface of the connecting member 10 in advance, the press-fitting operation becomes easy.
[0025]
Subsequently, the sleeve 20 is press-fitted from the connection member 10 into the resin tube 30 from the side of the sleeve engaging portion 23 by a jig (not shown). At this time, while the sleeve 20 elastically deforms the connecting member 10 and the cylindrical portion 35 of the resin tube 30 by the inclined surface 25 of the sleeve engaging portion, the sleeve engaging portion 23 reaches the second peak portion 33 of the resin tube 30. When the sleeve is press-fitted to the position where it is pressed, the sleeve stepped portion 24 is engaged with and fixed to the second engaged portion 33a.
[0026]
At this time, by setting the hypotenuse of the second peak portion 34 at 70 ° to 90 °, preferably 80 ° to 90 ° with respect to the axis of the resin tube 30, the step portion 24 and the second engaged portion 33a are connected to each other. Engagement becomes more reliable and the pull-out strength of the resin tube 30 can be increased. The valley portion 36 adjacent to the second peak portion 33 has a smaller diameter than the cylindrical portion 35, so that the sleeve engaging portion 23 does not exceed the second peak portion 32 of the resin tube 30 during the press-fitting operation. , And surely stop at the engagement position. In this case, the outer diameter of the sleeve cylindrical portion 21 needs to be set larger than the inner diameter of the second connecting portion 12 of the connecting member. In this state, the second connection portion 12 of the connection member is sandwiched and held between the sleeve cylindrical portion 21 and the connection end portion 31 of the tube in a compressed state. By adjusting the amount of compression, it is possible to cope with various sealing pressures. In addition, by applying a lubricant to the inner surface of the connecting member 10 in advance, the press-fitting operation becomes easy.
[0027]
Next, in order to attach the connecting member 10 to the pipe P, the first connecting portion 11 of the connecting member 10 is extrapolated to the pipe P over the bead Pa of the pipe P, and the first connecting portion 11 is connected to the clamp 40 and the pipe P. In a compressed state. Note that the clamp 40 is not always necessary when used at a relatively low sealing pressure.
[0028]
(6) Action and Effect of Embodiment Since the connection member 10 made of an elastic material is tightly held in a compressed state by the resin tube 30 and the sleeve 20, sufficient sealing properties can be obtained. Further, since the connecting member 10 and the sleeve 20 are mechanically engaged with the inner peripheral portion of the resin tube 30, sufficient pull-out strength can be obtained.
[0029]
The resin tube 30 is composed of a cylindrical connection end 31 and bellows (32, 33, 34), and the first and second engaged portions (32a, 33a) can be formed in the bellows. . Accordingly, since it is not necessary to separately provide the first and second engaged portions (32a, 33a), the structure of the resin tube is simplified, and the manufacture becomes easy.
[0030]
The present invention is not limited to the above embodiment, but can be implemented in various modes without departing from the scope of the invention.
[0031]
For example, as shown in FIG. 3, an annular protrusion 37 can be formed on the inner peripheral surface of the connection end 31 of the tube. Thereby, the compression amount is partially increased in the second connection portion 12 of the connection member, and the sealing performance is further improved without affecting the press-fitting workability.
[0032]
As shown in FIG. 4, an annular sleeve projection 26 can be formed on the outer periphery of the rear end of the sleeve 20. Thereby, the compression amount is partially increased in the second connection portion 12 of the connection member, and the sealing performance is further improved without affecting the press-fitting workability.
[0033]
In the above embodiment, the engagement portion 13 of the connection member is formed in a complete ring shape, but may be partially formed with a protrusion. Thereby, the elastic deformation of the engaging portion 13 at the time of press-fitting is apt to occur, so that press-fitting workability is improved. In particular, it is preferable to provide the notch 16 in the axial direction from the end face of the connecting member 31 as shown in FIG. At the time of press-fitting, the engaging portion 13 bends radially inward from the bottom of the notch 16 as a starting point, so that the outer diameter at the time of insertion can be reduced, so that press-fitting workability is further improved. The width and the number of the notches may be appropriately selected so as to secure a sufficient pull-out strength.
[Brief description of the drawings]
FIG. 1 is a half sectional view showing a state in which a pipe P and a resin tube 30 are connected by a connection structure according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram illustrating an operation of fixing a pipe with a pipe fixing member 20.
FIG. 3 is a half sectional view showing another embodiment of the resin tube.
FIG. 4 is a half sectional view showing another aspect of the sleeve.
FIG. 5 is a plan view showing another aspect of the connection member.
FIG. 6 is a half sectional view showing a known connection structure.
[Explanation of symbols]
Reference Signs List 10 connecting member 11 first connecting portion 12 second connecting portion 13 engaging portion 14 step portion 15 inclined surface 16 notch 20 sleeve 21 sleeve cylindrical portion 23 sleeve engaging portion 24 sleeve stepped portion 25 sleeve inclined surface 26 sleeve protrusion 30 Tube 31 Connection end 32 First peak 32a First engaged portion 33 Second peak 33a Second engaged portion 34 Third peak 35 Cylindrical portion 36 First valley 37 Projection P Pipe Pa Bead

Claims (4)

A cylindrical connecting member made of an elastic material having a first connecting portion connected to the pipe, and a second connecting portion connected to the inner peripheral surface side of the resin tube; A cylindrical sleeve disposed on the inner peripheral surface of the connecting portion and having an outer diameter larger than the inner diameter of the connecting member;
With
The resin tube is
A tubular connection end;
A first engaged portion that engages with an engaging portion provided on an outer periphery of a second connecting portion of the connecting member;
A second engaged portion engaged with an engaging portion provided on an outer periphery of the sleeve,
A second connecting portion of the connecting member is held in a compressed state between the connecting end of the sleeve and the resin tube;
A pipe connection structure characterized by the above-mentioned. The pipe connection structure according to claim 1, wherein the resin tube includes a cylindrical opening end and a bellows portion, and the first and second engaged portions are formed in the bellows portion. The pipe connection structure according to claim 1, wherein an annular protrusion is formed on an outer periphery of a rear end of the sleeve. The said 2nd connection part has a cyclic | annular protrusion formed in the edge part of the said connection member, and this protrusion has a notch formed in the axial direction, The said 1st part. 4. The pipe connection structure according to any one of items 1 to 3.

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