JP4083433B2 - Resin tube terminal connection structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a connection structure for resin tube terminals, and more particularly to a structure for connecting resin tube terminals used for brake piping, fuel supply piping of automobiles, and hydraulic / pneumatic piping of industrial machines and machine tools.
[0002]
[Prior art]
In automobiles, industrial machines, machine tools, and the like, resin tubes are widely used as tubes for flowing various fluids such as gasoline, oil, air, and water. Resin tubes have many advantages such as being lighter in weight, superior in corrosion resistance, and flexible compared to metal tubes.
[0003]
In addition, when connecting the terminal of this type of resin tube (hereinafter referred to as a resin tube) with a mating component having a bamboo shoot-shaped connection terminal, it is not necessary to use a connection component such as a pipe joint and press-fit into the connection terminal. There is an advantage that it can be simply connected.
[0004]
FIG. 3 shows a connecting part for connecting a terminal of a conventional resin tube.
[0005]
In FIG. 3, reference numeral 10 indicates a resin tube, and 12 indicates a counterpart component to which the resin tube 10 is connected. A press-fit connecting portion 14 into which the end of the resin tube 10 is press-fitted is integrally provided at the end of the mating component 12.
[0006]
The press-fit connection portion 14 has a step 15 formed on the outer peripheral portion thereof in about two to three steps. The press fitting connection portion 14 having a bamboo shoot shape of this kind has been widely used for press fitting connection of the end of the resin tube 10 conventionally. An O-ring 16 is attached to the distal end portion of the press-fit connection portion 14.
[0007]
The outer diameter of the bamboo-push-shaped press-fit connecting portion 14 is slightly larger than the inner diameter of the resin tube 10. By press-fitting the resin tube 10, the resin tube 10 is deformed and closely adheres to the shape of the bamboo shoot, and comes off. It can be securely connected so as not to
[0008]
[Problems to be solved by the invention]
When the resin tube is press-fitted into the bamboo-push-shaped press-fit connection part, as shown in FIG. 3, the vicinity of the end of the resin tube is gripped by the chuck 17 or the like and press-fitted into the press-fit connection part 14. Therefore, the portion that grips the resin tube with the chuck is the rear portion from the portion that fits into the press-fit connection portion 14.
[0009]
Further, in order to ensure the connection strength, the step 15 on the outer peripheral portion of the press-fit connection portion needs to be at least two or three steps, and therefore it is impossible to shorten the length of the press-fit connection portion to some extent. If the part gripped by the chuck is included, the straight part becomes longer. Since this straight portion is long, there is a problem that it is subjected to bending restrictions.
[0010]
Next, when press-fitting the resin tube, as shown in FIG. 4, if the terminal is not expanded, the tip may bite the O-ring 16 when it is press-fitted, and may be damaged or displaced. There is a problem in that it is necessary to perform tube expansion processing on the terminal in advance, which increases man-hours and increases costs.
[0011]
Accordingly, an object of the present invention is to solve the problems of the prior art, without the need for pipe expansion processing on the terminal, and without being damaged the O-ring . It is to provide a connection structure.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is characterized in that a terminal of a resin tube is press-fitted into a press-fit connection part of a mating part having a stepped part, and the terminal of the resin tube is connected to the mating part only by press-fitting. In the connection structure for performing, a cylindrical portion having an outer diameter that is the same as or slightly larger than the inner diameter of the resin tube, and a trapezoidal cone-shaped step portion having only one step having a maximum outer diameter larger than the cylindrical portion, the configure press-fit connection of the mating component, the terminal of the resin tube to form a chevron portion of only one stage forming the mountains radially outward to engage the locking surface of the step portion from the The step portion of the press-fit connection portion has a step having a maximum outer diameter at the boundary between the tapered surface and the locking surface, and an O-ring groove is formed at the base of the step. is there.
[0013]
According to the first aspect of the present invention, when the terminal processed portion of the resin tube gets over the stepped portion, the resin tube is caught in the stepped portion, so that it does not come out even when a force for pulling out the resin tube is applied, and the connection strength is ensured. together and can be, it does not damage the O-ring at the time of press-fitting.
[0014]
The invention according to claim 2 is a connection structure for press-fitting a terminal of a resin tube into a press-fit connection part of a mating part having a stepped part, and connecting the terminal of the resin tube to the mating part only by press-fitting , Press fitting connection of the mating part from a cylindrical portion having an outer diameter that is the same as or slightly larger than the inner diameter of the resin tube, and a stepped portion having a trapezoidal cone shape having a maximum outer diameter larger than the cylindrical portion. part configure, the step portion of the front Symbol press-fit connecting portion has a step having a maximum outer diameter at a boundary between the engaging surface and the tapered surface, a groove for O-ring is formed on the root portion of the step The resin tube comprises a bellows tube having a cylindrical end portion fitted to the cylindrical portion and a bellows portion continuous from the end portion, and the terminal-side first step bellows portion is the step portion. der which is characterized in that to engage the .
[0015]
According to the second aspect of the present invention, when the resin tube is press-fitted, the tip of the resin tube gets over the step portion and at the same time jumps over the O-ring, so that the O-ring is damaged at the tip of the tube and the sealing performance is impaired. Can be prevented.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a resin tube terminal connection structure according to the present invention will be described with reference to the accompanying drawings.
[0019]
First Embodiment FIG. 1 is a view showing a connection structure of a resin tube terminal according to a first embodiment of the present invention. FIG. 1 (a) shows a state before the resin tube 20 is press-fitted into a mating part 22, FIG. b) shows after press-fitting. In FIG. 1, reference numeral 24 indicates a press-fit connection portion provided integrally with the counterpart component 22, and the resin tube 20 is simply connected by press-fitting into the press-fit connection portion 24.
[0020]
The resin tube 20 is a tube made of nylon resin or the like and has a certain degree of hardness. An end portion of the resin tube 20 is processed in advance with a chevron portion 26 that is processed so as to form a corrugated peak toward the outside in the radial direction. In the case of this embodiment, only one angle portion 26 is formed.
[0021]
The press-fit connecting portion 24 includes a cylindrical portion 27 extending from the counterpart part 22 and a stepped portion 30 that is integrated with the cylindrical portion 27. The outer diameter of the cylindrical portion 27 of the press-fit connecting portion 24 is larger than the inner diameter of the resin tube 20. Is also set slightly larger. The outer diameter of the cylindrical portion 27 may be the same as the inner diameter of the resin tube 20.
[0022]
In the press-fit connection portion 24, only one step portion 30 is formed. The stepped portion 30 is composed of a surface that rises radially outward from the outer periphery of the cylindrical portion, a locking surface 31 on which the chevron 26 of the resin tube 20 is hooked, and a tapered surface 32 that is inclined while gradually reducing the diameter toward the tip. The boundary between the locking surface 31 and the tapered surface 32 is the highest, and a step is formed between the outer peripheral surface of the cylindrical portion 27. As for the outer diameter of the stepped portion 30, the maximum outer diameter is larger than the outer diameter of the cylindrical portion 27, becomes the minimum outer diameter at the tip, and is smaller than the inner diameter of the resin tube 20 here.
[0023]
A rotating groove 33 is formed near the base of the stepped portion 30, and an O-ring 34 is fitted in the groove 33.
[0024]
Next, the operation and effect of this embodiment will be described.
[0025]
In FIG. 1A, the resin tube 20 is gripped by a chuck (not shown), the end of the resin tube 20 faces the press-fit connection portion 24 of the mating component 22, and then the resin tube 20 is press-fit into the press-fit connection portion 24. . In the first stage where the press-fitting is started, the tapered surface 32 of the step portion 30 serves as a guide, and when it is gradually inserted, the end of the resin tube 20 gets over the step portion 30 as shown in FIG. Reaches the cylindrical portion 27.
[0026]
When the resin tube 20 has been press-fitted, as shown in FIG. 1B, the chevron 26 of the resin tube 20 is in a state of being caught by the stepped portion 30, so that a force to pull out the resin tube 22 is applied. In addition, the inner surface of the angle portion 26 does not come out of the locking surface 31 and comes out, so that the connection strength can be ensured.
[0027]
In this state, the end of the resin tube 20 is in close contact with the cylindrical portion 27 of the press-fit connecting portion 24 and can be sealed airtight or liquid-tight by the O-ring 34. In addition, when the resin tube 20 is press-fitted, the O-ring 34 jumps over the step portion 30 at the same time, so that the O-ring 34 is not damaged or detached from the groove 33 at the tip of the tube. The sealing performance of the O-ring 34 is not impaired.
[0028]
Further, since the stepped portion 30 of the press-fit connection portion 24 is only one step, the resin tube 20 is bent at a position closer to the terminal as compared with the case where the conventional bamboo shoot-type press-fit connection portion is used. Therefore, there is an advantage that the degree of freedom in piping layout is increased.
[0029]
Second Embodiment Next, a resin tube connection structure according to a second embodiment of the present invention will be described with reference to FIG.
[0030]
In the second embodiment, a bellows-like resin tube is used as the resin tube. The structure of the press-fit connection part of the mating part is the same as in FIG. 1, and the same components are denoted by the same reference numerals, and detailed description thereof is omitted.
[0031]
In the bellows-like resin tube 40, a straight cylindrical portion 41 is formed at the end, and a bellows portion is formed at a constant pitch following the cylindrical portion 41. Among these, the bellows part 42 in the first stage corresponds to the chevron part 26 in the resin tube 10 of the first embodiment.
[0032]
When the bellows-like resin tube 40 is completely press-fitted into the press-fit connecting portion 24, as shown in FIG. 2, when the cylindrical portion 41 of the bellows-like resin tube 40 gets over the stepped portion 30, the first bellows-like portion 42 is stepped. Since it is caught by the portion 30, even if a force for pulling out the resin tube 40 is applied, the inner surface of the first step bellows portion 42 does not come into contact with the locking surface 31 and the connection strength is ensured. it can. Further, as in the first embodiment, the O-ring 34 is not damaged when the cylindrical portion 41 gets over the stepped portion 30.
[0033]
When the bellows-like resin tube 40 is used, it is not necessary to process the chevron 26 at the end of the resin tube 20 as in the first embodiment, and the resin tube 40 having an inner diameter corresponding to the press-fit connection portion 24 is used as it is. Is possible. And since it is a bellows-like tube, there exists an advantage which is easy to bend and the freedom degree on piping layout improves.
[0034]
【The invention's effect】
As is clear from the above description, according to the first and second aspects of the invention, when the terminal processed portion of the resin tube gets over the stepped portion, the stepped portion is caught. However, even if a force for pulling out the resin tube is applied, the resin tube does not come off, the connection strength can be ensured, and the O- ring is not damaged during press-fitting. Furthermore, since one step is sufficient, the length of the press-fit connection portion is shortened, and when using a bent tube, the bending position can be brought closer to the terminal, so that the degree of freedom in piping layout is improved. The effect of.
[0035]
Moreover, according to the invention which concerns on Claim 4, it becomes possible to use the bellows-shaped resin tube of the internal diameter corresponding to a press-fit connection part as it is, and also there exists an advantage which the degree of freedom on piping layout improves further easily. Furthermore, according to the invention which concerns on Claim 5, since a resin tube terminal gets over an O-ring at the same time it gets over a level | step-difference part, it can prevent damaging an O-ring at the tube tip.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional side view showing a resin tube terminal connection structure according to an embodiment of the present invention.
FIG. 2 is a partial cross-sectional side view showing a connection structure of a resin tube terminal according to another embodiment of the present invention.
FIG. 3 is a longitudinal sectional view showing a connection structure of a resin tube terminal according to a conventional technique.
FIG. 4 is a view showing a resin tube end subjected to pipe expansion processing.
[Explanation of symbols]
20 resin tube 22 mating part 24 press-fit connection portion 26 chevron portion 27 cylindrical portion 30 step portion 31 locking surface 32 taper surface 34 O-ring 40 bellows-like resin tube 41 cylindrical portion 42 first step bellows portion

Claims (2)

In the connection structure for press-fitting the end of the resin tube into the press-fit connection part of the mating part having a stepped portion, and connecting the terminal of the resin tube to the mating part only by press-fitting ,
Press fitting connection of the mating part from a cylindrical portion having an outer diameter that is the same as or slightly larger than the inner diameter of the resin tube, and a stepped portion having a trapezoidal cone shape having a maximum outer diameter larger than the cylindrical portion. Part
On the end of the resin tube, a chevron portion having only one step that forms a mountain toward the outside in the radial direction to be locked to the locking surface of the stepped portion ,
The step portion of the press-fit connection portion has a step having a maximum outer diameter at a boundary between the tapered surface and the locking surface, and an O-ring groove is formed at a base portion of the step. A resin tube terminal connection structure. In a connection structure for press-fitting a terminal of a resin tube into a press-fit connection part of a mating part having a stepped part, and connecting the terminal of the resin tube to the mating part only by press-fitting ,
Press fitting connection of the mating part from a cylindrical portion having an outer diameter that is the same as or slightly larger than the inner diameter of the resin tube, and a stepped portion having a trapezoidal cone shape having a maximum outer diameter larger than the cylindrical portion. Part
The step portion of the front Symbol press-fit connecting portion has a step having a maximum outer diameter at a boundary between the engaging surface and the tapered surface, a groove for O-ring is formed on the root portion of the step,
The resin tube comprises a bellows tube having a cylindrical end portion fitted to the cylindrical portion and a bellows portion continuous from the end portion,
The resin tube terminal connection structure, wherein the terminal side first step bellows portion engages with the step portion .

Images