JP2011031579A - Method for forming expanded part of resin tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming an expanded part of a resin tube hardly causing a bend during expanding the tube and a difficult removal of a mold after expanding the tube and showing good dimensional stability of the expanded tube. <P>SOLUTION: The method for forming the expanded part of the resin tube 1 comprises: forming a pair of circumferential grooves 3a and 3a each having a flow passage 2a in a lengthwise direction and one closed end; after forming a fluid nozzle 2 mounted between the circumferential grooves 3a and 3a and having an opening 4 communicating with the flow passage 2a, attaching seal rings 3 and 3 in the circumferential grooves 3a and 3a of the fluid nozzle 2; inserting the fluid nozzle 2 in the resin tube 1 to form a pressurization space 5; attaching separate molds 6a and 6b each having the circumferential surface, which forms the inner expanded space 7 and coincides with the outside shape of the expanded tube, to the outer circumference of the pressurization space 5 of the resin tube 1; heating the resin tube 1 and loading adhesion force to the separate molds 6a and 6b; and introducing the pressurized fluid via the opening 4 of the fluid nozzle 2 to the pressurization space 5 to form the expanded part 1a in the resin tube 1. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for forming an expanded portion of a resin tube, and more particularly to a method for forming an expanded portion of a resin tube used for a resin hose for fuel.

  In a fuel pipe for a vehicle, a resin tube for transporting fuel is connected to a mating pipe attached to a fuel pump unit, a fuel filter or the like via a connector. A quick connector with a resin tube according to such a conventional example will be described below with reference to FIGS. FIG. 5 is a view showing a quick connector with a resin tube according to a conventional example in a connected state with a mating pipe, and FIG. 6 is a view showing a method for forming a press-fit portion in the resin tube of FIG.

  The quick connector 16 with a resin tube according to this conventional example has a connector body 18, a retainer 20, an O-ring 22 as a seal member, and a bush 24, and the resin tube 10 is press-fit into which a press-fit portion 28 is press-fitted. The portion 10A is preliminarily expanded before press-fitting, and the press-fitting portion 28 is press-fitted and integrated with the expanded press-fit portion 10A.

  According to this conventional example, the pre-heated tube expansion pin 48 having a shape corresponding to the shape of the inner surface of the press-fit portion 10A is inserted into the end portion of the resin tube 10 in the axial direction. That is, the tube expansion pin 48 is inserted into the resin tube 10 while the end of the resin tube 10 is softened by the heat of the tube expansion pin 48 and expanded. Thereafter, the tube expansion pin 48 is removed from the resin tube 10 to form a tube-shaped press-fit portion 10A at the end of the resin tube 10 (see Patent Document 1).

  However, the expansion method of the resin tube 10 according to this conventional example is difficult to insert into the resin tube 10 because the tube expansion pin 48 is hot, and the temperature of the tube expansion pin 48 decreases during the operation, and the expanded portion of the resin tube 10 There are problems that the dimension becomes unstable, the resin tube terminal is bent due to the hard insertion, the tube expansion pin 48 after the tube expansion is difficult to pull out, and the resin tube expanded portion is easily deformed.

Japanese Patent Laid-Open No. 2005-180662

  Accordingly, an object of the present invention is to provide a method for forming a tube expansion portion of a resin tube, in which the resin tube is not bent at the time of tube expansion, and the mold after the tube expansion is not easily released, and the stability of the tube expansion dimension is good. .

  According to a first aspect of the present invention, there is provided a method for forming a pipe-expanded portion of a resin tube in the method for forming a pipe-expanded portion of a resin tube. A pair of circumferential grooves is formed, and a fluid nozzle having at least one aperture communicating with the flow path is formed between the pair of circumferential grooves, and then a pair of fluid grooves formed in the fluid nozzle is formed. A seal ring is attached to each of the circumferential grooves, and then the fluid nozzle is inserted into the resin tube, and a pressurizing space is formed by the outer periphery of the fluid nozzle, the inner periphery of the resin tube, and the pair of seal rings.

  On the other hand, a split mold in which the peripheral surface forming the inner pipe expansion space is formed so as to match the outer shape of the pipe expansion is mounted on the outer periphery of the pressurizing space of the resin tube, and the resin tube is heated. And a pressure expansion fluid is introduced into the pressure space from the flow path of the fluid nozzle through the opening to form a tube expansion portion in the resin tube. Is.

  According to a second aspect of the present invention, there is provided a method for forming an expanded portion of a resin tube, wherein the expanded portion of the resin tube is cut after the split mold is released. It is characterized by this.

  The method of forming the expanded portion of the resin tube according to claim 3 of the present invention is the method of forming the expanded portion of the resin tube according to claim 1 or 2, wherein the heating of the resin tube preheats the resin tube itself, Alternatively, the heating is performed through heating of any one or more of the split mold, the fluid nozzle, and the pressurized fluid.

  According to a fourth aspect of the present invention, there is provided a method for forming a pipe expansion portion of a resin tube according to any one of the first to third aspects. And, after the resin tube is expanded, the cooling fluid is immediately passed through the cooling fluid flow path for cooling.

  According to the method of forming the expanded portion of the resin tube according to claim 1 of the present invention, the flow path is provided inside the longitudinal direction and one end is sealed, and a pair of circumferences are provided at predetermined positions in the longitudinal direction with a predetermined interval. After forming a fluid nozzle in which a groove is formed and at least one opening communicating with the flow path is provided between the pair of circumferential grooves, a seal ring is provided in each of the pair of circumferential grooves formed in the fluid nozzle. Next, the fluid nozzle is inserted into the resin tube, and a pressurized space is formed by the fluid nozzle outer periphery, the resin tube inner periphery, and the pair of seal rings.

  On the other hand, a split mold in which the peripheral surface forming the inner pipe expansion space is formed so as to match the outer shape of the pipe expansion is mounted on the outer periphery of the pressurizing space of the resin tube, and the resin tube is heated. Since the pressurized fluid is introduced into the pressurized space from the flow path of the fluid nozzle through the opening to form the expanded portion in the resin tube, Easy tube expansion in the middle in the longitudinal direction, and the temperature change of the split mold is small during the operation, so the dimensions of the expanded tube portion are stable, the insertion does not become hard during the tube expansion operation, and the resin tube does not bend. The split mold can be easily released, and deformation of the resin tube expanded portion can be suppressed.

  Further, according to the method for forming the expanded portion of the resin tube according to claim 2 of the present invention, the expanded portion of the resin tube is reliably formed since the expanded portion of the resin tube is cut after releasing the split mold. In addition, since the temperature change of the split mold is small during the work, the dimensions of the pipe expansion part are stable, the resin tube does not bend during the pipe expansion work, and it is easy to release the split mold after the pipe expansion. The deformation of the expanded portion can be suppressed.

  Further, according to the method for forming the expanded portion of the resin tube according to claim 3 of the present invention, the heating of the resin tube may be performed by heating the resin tube in advance, or by dividing the mold, the fluid nozzle, or the pressurized fluid. Since it is made through any one or more heating, the expanded portion of the resin tube can be reliably heated.

  Furthermore, according to the method for forming the expanded portion of the resin tube according to claim 4 of the present invention, a cooling fluid channel is provided in the split mold, and immediately after the expansion of the resin tube, the cooling fluid channel is provided in the cooling fluid channel. Cooling through the tube prevents the resin tube from losing its shape after being heated and expanded, enabling early mold release.

BRIEF DESCRIPTION OF THE DRAWINGS It is process drawing for demonstrating the expansion part formation method of the resin hose which concerns on embodiment of this invention, Comprising: FIG. (A) is a figure which shows the process of inserting the front-end | tip of a fluid nozzle in a resin hose terminal, FIG. ) Is a diagram showing a process of mounting the split mold on the outer periphery of the pressurized space portion of the resin hose, and FIG. (C) is a diagram showing a process of introducing a pressurized fluid into the pressurized space to form a pipe expanding portion in the resin hose. is there. It is process drawing following FIG. 1 for demonstrating the expansion part formation method of the resin hose which concerns on embodiment of this invention, Comprising: FIG.2 (d) is the process of forming a expansion part in the resin hose terminal after mold release. FIG. 2E is a view showing a process of press-fitting the expanded portion of the obtained resin hose terminal into the connector. FIG. 5 is a schematic diagram for explaining a tube expansion portion for positioning a clamp according to an application example in which a tube expansion portion is formed in an intermediate portion of a resin hose, in which FIG. It is sectional drawing which shows arrow AA of figure (a). FIG. 2 is a part of a process diagram for explaining a tube expansion portion forming method for forming a clamp positioning tube expansion portion in an intermediate portion of a resin hose, and is a view corresponding to FIG. It is a figure which shows the quick connector with a resin tube which concerns on a prior art example in the connection state with the other party pipe. It is a figure which shows the formation method of the press-fit part in the resin tube of FIG.

  Next, an embodiment of the present invention will be described with reference to the attached FIGS. 1 and 2 by taking as an example a connection between a fuel resin hose (hereinafter also simply referred to as a resin hose) and a connector.

  1 and 2 are process diagrams for explaining a method for forming an expanded portion of a resin hose according to an embodiment of the present invention. FIG. 1 (a) shows a process of inserting the tip of a fluid nozzle into a resin hose terminal. FIG. 1B is a diagram illustrating a process of attaching the split mold to the outer periphery of the pressurized space of the resin hose, and FIG. 1C is an enlarged portion of the resin hose by introducing a pressurized fluid into the pressurized space. 2 (d) is a diagram showing a step of forming a tube expansion portion on the resin hose terminal after release, and FIG. 2 (e) is a diagram showing a step of forming the tube expansion portion of the obtained resin hose terminal to the connector. It is a figure which shows the process to press-fit.

  A fuel resin hose 1 according to an embodiment of the present invention is usually configured by coating a protective cover made of EPDM (ethylene / propylene / diene rubber) on the outer periphery of a polyamide resin hose. Assume that the hose outer diameter is d1. A connector 8 (see FIG. 2 (e)) to which the fuel resin hose 1 is press-fitted and connected is a joint similar to the connector main body 18 according to the conventional example described with reference to FIG.

  First, as shown in FIG. 1 (a), a pair of circumferential grooves 3a and 3a are formed with a flow path 2a inside the longitudinal direction and the tip sealed, and with a predetermined interval L2 in the longitudinal direction near the tip. Then, a fluid nozzle 2 is prepared in which at least one opening 4 communicating with the flow path 2a is provided between the pair of circumferential grooves 3a and 3a. As a material of the fluid nozzle, stainless steel (SUS304 or the like) is suitable. Moreover, brass, carbon steel materials for machine structures (S45C etc.), etc. can be used.

  And after attaching O-rings 3 and 3 to a pair of above-mentioned peripheral grooves 3a and 3a, the tip of this fluid nozzle 2 is inserted in the terminal of fuel resin hose 1, respectively. Then, as shown in FIG. 1B, a sealed pressurizing space 5 is formed by the outer periphery of the fluid nozzle 2, the inner periphery of the resin hose 1, and the pair of O-rings 3 and 3. Here, when the resin hose 1 has a cross section other than an annular shape, for example, a polygonal cross section, the O-rings 3 and 3 are preferably seal rings that match the circumferential shape of the cross section.

  Here, the predetermined interval L2 in which the circumferential grooves 3a, 3a are formed is the length in the longitudinal direction of the expanded portion 1a formed by expanding the resin hose 1 described later, that is, the expanded length L1 (FIG. 1 ( c) and a length satisfying L2> L1 with respect to FIG. And, it is important for the predetermined interval L2 to have such a dimension in order to prevent leakage from the pressurized space 5 when a pressurized fluid described later is introduced. Also, it is important for the same reason that the outer diameter d2 of the O-rings 3, 3 after being mounted in the circumferential grooves 3a, 3a is d2 ≧ d0 with respect to the resin hose inner diameter d0. .

  Thereafter, when the two mating surfaces are brought into close contact with each other, the split dies 6a and 6b formed so that the inner diameter of the peripheral surface forming the tube expansion space 7 on the inside coincides with the tube expansion outer diameter D1 are added to the resin hose 1. It is mounted on the outer periphery of the pressure space 5 (see FIG. 1B).

  Here, the pipe expansion outer diameter D1 is a dimension determined from the pipe expansion inner diameter D0 (see FIG. 2 (e)) of the pipe expansion portion 1a in which the resin hose 1 is expanded beyond the tip outer diameter of the mating connector 8. Further, when the split surfaces of the split dies 6a and 6b are brought into close contact with each other, the diameter of the inner peripheral surface other than the peripheral surface forming the tube expansion space 7, that is, the split seal inner diameter D2 is in close contact with the outer periphery of the resin hose 1. In order to prevent leakage at the time of introducing the pressurized fluid described below, it is important to satisfy D2 <d1 with respect to the outer diameter d1 of the resin hose.

  Next, as shown in FIG. 1 (c), in order to bring the mating surfaces of the split dies 6a and 6b into close contact with each other, an adhesive force indicated by an arrow is applied and the resin hose 1 is heated to a temperature of 200 to 250 ° C. Then, a pressurized fluid pressurized to a pressure of 1.5 to 2.5 MPa is introduced from the flow path 2 a of the fluid nozzle 2 into the pressurized space 5 through the opening 4. Then, since the resin hose 1 is heated and softened, the resin hose 1 is expanded in the tube expansion space 7, and its outer periphery is expanded to the tube expansion outer diameter D1 formed on the inner periphery of the split molds 6a and 6b. .

  It is preferable that the resin hose 1 is heated through heating one or more of the split dies 6a and 6b, the fluid nozzle 2 and the pressurized fluid. When the split molds 6a, 6a are heated by an embedded sheathed heater, the expanded portion 1a of the resin hose 1 can be reliably heated, and when heated by the pre-heated pressurized fluid, the resin hose Since pressurization to 1 and heating are performed only with a pressurized fluid which is one medium, it is efficient. The resin hose 1 can be heated by heating the resin hose 1 itself with a sheathed heater or an air heater in advance.

  In addition, as the pressurized fluid, pressurized gas or liquid can be used, but use of compressed air is efficient because it is not necessary to dry the inside of the resin hose 1 after pressurization and is easy to handle. A good pressure operation is possible.

  When the split dies 6a and 6b are released after the diameter of the resin hose 1 is expanded, a tube expansion portion 1a is formed at an intermediate portion of the resin hose 1 as shown in FIG. Next, when the vicinity of the terminal side of the pipe expansion part 1a is cut as the cutting part C, the pipe expansion part 1b is formed at the hose terminal. The resin hose 1 and the connector 8 can be connected by press-fitting the expanded tube portion 1 b of the cut hose end into the press-fit portion 8 a of the connector 8.

  In addition, the application example of the pipe expansion part formation method which forms the pipe expansion part 1a in the intermediate part of the said resin hose 1 is demonstrated easily, referring attached drawing 3 and 4 below. FIG. 3 is a schematic diagram for explaining a tube expansion portion for positioning a clamp according to an application example in which a tube expansion portion is formed in an intermediate portion of a resin hose. FIG. FIG. 4B is a cross-sectional view taken along the line AA in FIG. 4A, and FIG. 4 is a partial view for explaining a method for forming the expanded portion for forming the expanded tube portion for positioning the clamp in the intermediate portion of the resin hose. FIG. 2 is a process diagram corresponding to FIG.

  That is, in the middle part of the resin hose 1, out of the expanded pipe parts 1a-1 and 1a-2 for restricting the fixing location of the clamp 9, first, up to the expanded pipe part 1a-1 far from the end of the hose. As described in the embodiment, the fluid nozzle 2 is inserted, and the expanded portion 1a-1 is formed through a predetermined process operation. Next, the fluid nozzle 2 is inserted from the end of the hose to the closer expanded portion 1a-2 as described in the embodiment of the present invention, and another expanded portion 1a-2 is formed through a predetermined process operation. To do.

  Alternatively, the expanded pipe portions 1a-1 and 1a-2 are formed by providing two pairs of O-rings 3 and 3 for one fluid nozzle 2, as shown in FIG. 2 may be expanded simultaneously.

  Thereafter, a clamp prepared in advance is wound between the pipe expansion portions 1a-1 and 1a-2, and a fastener such as a bolt passed through the through hole 9a is fastened to a fixing portion (not shown) to move the resin hose 1. Prevent and perform positioning. Here, the clamp 9 may be wound around the resin hose 1 in advance, and the expanded portions 1a-1 and 1a-2 may be formed on both sides of the clamp 9.

  As described above, according to the method of forming the expanded portion of the resin hose 1 according to the embodiment of the present invention, the flow path 2a is provided inside the longitudinal direction, one end is sealed, and the predetermined interval is provided in the longitudinal direction near the tip. A pair of circumferential grooves 3a, 3a having L2, and a fluid nozzle 2 having at least one aperture 4 communicating with the flow path 2a between the pair of circumferential grooves 3a, 3a. After the O-rings 3 and 3 are attached to the pair of circumferential grooves 3a and 3a, respectively, the tip of the fluid nozzle 2 is inserted into the end of the resin hose 1, and the outer periphery of the fluid nozzle 2 and the inner periphery of the resin hose 1 A pressure space 5 is formed by the pair of O-rings 3 and 3.

  On the other hand, the split dies 6a and 6b whose peripheral surface forming the inner pipe expansion space 7 is formed with the pipe outer diameter D1 are attached to the outer periphery of the pressurizing space 5 of the resin hose 1, and the split dies 6a and 6b are attached. In addition to applying an adhesion force that causes the resin hose 1 to be in close contact with each other, a pressurized fluid is introduced into the pressurized space 5 from the flow path 2a of the fluid nozzle 2 through the opening 4 while heating the resin hose 1. After expanding the resin hose 1 and releasing the split dies 6a and 6b, the expanded portion 1a of the resin hose 1 is formed. Furthermore, the expanded tube portion 1a is cut to form the expanded portion 1b of the hose terminal.

  As a result, the tube expansion of the resin hose is easy, and the temperature change of the split mold is small during the operation, so the dimensions of the tube expansion are stable, the insertion is hard during the tube expansion operation, and the resin hose is not bent and after the tube expansion It is possible to easily release the split mold, and it is possible to suppress deformation of the resin hose terminal portion.

  Next, regarding the method for forming the expanded portion of the resin hose according to the present invention, an embodiment of the fuel resin hose will be described below with reference to the attached FIGS. The specifications of the fuel resin hose and connector are as follows.

(1) Fuel resin hose ・ Material structure: Polyamide resin hose / EPDM protective cover ・ Hose dimensions: outer diameter d1 = 6 mm, inner diameter d0 = 2.5 mm
(2) Connector • Press fit part tip outer diameter: 3.0 mm
・ Press-fit part maximum outer diameter: 4.9mm

  First, as shown in FIG. 1 (a), a pair of circumferential grooves 3a and 3a having a width of 0.5 mm and a depth of 0.3 mm are provided in the vicinity of a sealed tip provided with a channel 2a having a diameter of 0.8 mm in the longitudinal direction. The fluid nozzle 2 made of SUS304 in which two openings 4 are provided between the pair of circumferential grooves 3a and 3a is formed by cutting and drilling.

  Next, an O-ring made of fluoro rubber having an inner diameter of 1.6 mm and a wire diameter of 0.4 mm is attached to each of the pair of circumferential grooves 3a and 3a of the fluid nozzle 2, and the O-ring outer diameter d2 after installation is 2.6 mm. I did it.

  Then, the tip of the fluid nozzle 2 is inserted into the end of the fuel resin hose 1 and, as shown in FIG. 1B, the fluid nozzle 2 outer periphery, the resin hose 1 inner periphery, and a pair of O-rings 3 and 3 A sealed pressurized space 5 was formed. Thereafter, when a sheathed heater is embedded inside and the mating surfaces of the two are brought into close contact with each other, the diameter of the inner surface forming the tube expansion space 7 on the inner peripheral side coincides with the tube expansion outer diameter D1 = 6.5 mm, and the length is expanded. The split dies 6a and 6b formed to have a length L1 = 20 mm are attached to the outer periphery of the pressure space 5 of the resin hose 1 as shown in FIG.

  Then, the clamping surfaces of the split dies 6a and 6b are brought into close contact with each other using a clamp, and the pressurized space is passed through the opening 4 from the flow path 2a of the fluid nozzle 2 while heating the sheathed heater to a temperature of 200 ° C. 5, compressed air of 2.0 MPa is introduced. Then, the resin hose 1 is heated and softened, expands in the tube expansion space 7, and its outer periphery is expanded to the tube expansion outer diameter D1 = 6.5 mm of the inner periphery of the split molds 6a and 6b. The

  Then, after the diameter of the resin hose 1 is expanded and the expanded pipe portion is cooled through the split mold, the split molds 6a and 6b are released, and as shown in FIG. In addition, the expanded portion 1a having an outer diameter D1 = 6.5 mm, an inner diameter D0 = 3.5 mm, and a length L1 = 20 mm was formed. Therefore, the expanded portion 1b of the hose terminal was formed by cutting a portion 16 mm from the tip of the expanded portion 1a as a cut portion C.

  As described above, according to the method for forming the expanded portion of the resin hose according to the present invention, the expansion operation of the resin hose is facilitated, and since the temperature change of the split mold is small during the operation, the size of the expanded portion is stabilized and the expanded tube Insertion becomes hard during the work, the resin hose does not bend, the split mold can be easily released after the pipe expansion, and the deformation of the resin hose pipe expansion section can be suppressed.

  In addition, in the said embodiment, although the pipe expansion part formation method which forms a pipe expansion part in the terminal of the resin hose for fuels was demonstrated to the example, the resin tube expansion pipe formation method concerning the present invention is a resin tube for fuel. Without being limited to the resin hose, any resin tube using a thermoplastic resin can be applied regardless of the application.

C: cutting part,
d0: Resin hose inner diameter, d1: Resin hose outer diameter,
d2: O-ring outer diameter after mounting the circumferential groove,
D0: inner diameter of expanded pipe, D1: outer diameter of expanded pipe,
D2: Split seal inner diameter,
L1: Length of tube expansion, L2: Predetermined interval at which a circumferential groove is formed,
1: (for fuel) resin hose, 1a, 1b, 1a-1, 1a-2: pipe expansion part,
2: fluid nozzle, 2a: flow path,
3: O-ring, 3a: Circumferential groove,
4: Open hole,
5: Pressurized space,
6a, 6b: Split type,
7: Expanded space,
8: Connector, 8a: Press-fit part,
9: Clamp, 9a: Through hole

Claims (4)

In the method for forming the expanded portion of the resin tube,
At least one communicating with the flow path is formed between the pair of circumferential grooves, having a flow path inside the longitudinal direction and having one end sealed and having a predetermined interval at a predetermined position in the longitudinal direction. After forming a fluid nozzle with a number of apertures,
A seal ring is attached to each of the pair of circumferential grooves formed in the fluid nozzle,
Next, the fluid nozzle is inserted into the resin tube, and a pressurizing space is formed by the fluid nozzle outer periphery, the resin tube inner periphery, and the pair of seal rings,
A split mold formed so that the peripheral surface forming the inner tube expansion space matches the tube outer shape is mounted on the outer periphery of the pressure space of the resin tube,
While heating the resin tube, load the adhesive force to adhere the split molds to each other,
A method for forming an expanded portion of a resin tube, wherein a pressurized fluid is introduced into the pressurized space from the flow path of a fluid nozzle through the opening to form a expanded portion in the resin tube.   2. The method of forming the expanded portion of the resin tube according to claim 1, wherein after the split mold is released, the expanded portion of the resin tube is cut, and the expanded portion is formed at the end of the resin tube.   The heating of the resin tube is performed by heating the resin tube itself in advance or by heating any one or more of the split mold, the fluid nozzle, and the pressurized fluid. 2. A method for forming an expanded portion of a resin tube according to 2   The cooling fluid flow path is provided in the split mold, and the cooling fluid is immediately passed through the cooling fluid flow path after the resin tube is expanded. A method for forming an expanded portion of a resin tube as described.

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