JP2627653B2 - Method of manufacturing bent hose with protector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method of manufacturing a bent hose with a protector suitable as a fuel hose, a water hose, an oil hose and the like for a vehicle.

Hereinafter, in this specification, description will be given taking a fuel hose as an example.

<Prior Art> Conventionally, a fuel hose may be formed of a thermoplastic resin material (polyamide or the like) from the viewpoints of weight reduction and improvement of pressure resistance. The fuel hose must be provided with a tubular protector so as not to affect the heat of the surroundings (engine, etc.) (see Japanese Patent Application Laid-Open No. 58-163628).
This protector is made of synthetic rubber (silicone rubber or the like).

By the way, recently, there is a high tendency that the engine room is narrowed. Therefore, to avoid interference with other parts,
Need to bend the fuel hose.

Therefore, conventionally, a bent fuel hose 1 (see FIG. 1) has been manufactured as follows.

Hose part 3 of thermoplastic resin (hereinafter referred to as “resin hose part”)
That. ) And the cylindrical protector 5 are extruded. Then, the two are fitted to form the hose body 7 into a straight tubular shape.

Thereafter, the hose body 7 is gripped and fixed with a chuck (not shown), and the bases 9 are attached to both ends of the resin hose 3 (FIG. 6).

Next, as shown in FIG. 7, the straight tube main body 7 is set in a bending mold 15 and heated by the mold 15 to plasticize the resin hose section 3. Reference numeral 17 in the figure is a heater,
It is connected to a power supply (not shown). Thereafter, the resin hose portion 3 is solidified by air cooling (air is blown into the hose), and the shape of the hose body 7 is fixed in a bent state.

<Problems to be solved by the invention> However, when observing the process of bending the hose body 7, the following waste was found.

That is, in this step, at least the resin hose portion 3 may be plastically deformed in order to plastically deform the straight tubular hose body portion 7. This is because the protector 5 made of synthetic rubber follows this.

Nevertheless, in this step, since the hose body 7 is heated from the outside by using the molding die 15, the protector 5 is heated first. Therefore, it takes a long time before the resin hose portion 3 is plasticized.

The upper limit of the temperature applied to the hose body 7 is limited in order to guarantee the performance of the resin hose 3.
For example, when the resin hose portion 3 is made of polyamide, the upper limit temperature is 185 ° C.

In addition, if the temperature of the protector 5 is raised, the thermal effect may reach the resin hose portion 3, so that it takes time to cool the resin hose portion 3 to solidify.

According to the study of the present inventor, the resin hose portion 3 (made of polyamide) having a thickness of 1 mm and an outer diameter (diameter) of 8 mm has a thickness of 2 mm.
When the protector 5 is mounted, the resin hose 3
It took 180 seconds to raise the mold to 170 ° C. to plasticize the resin.

On the other hand, to cool the resin hose section 3, air at 30 ° C is used.
I had to blow in the hose for 180 seconds.

In order to prevent the temperature from rising to the protector 5, the resin hose 3 may be bent in advance.

However, if this is done, the protector 5 cannot be externally mounted on the resin hose 3 depending on the shape required for the hose body 7, which is not preferable.

Molding (eg, injection molding) of the protector 5 using the bent resin hose portion 3 as an insert may be considered.
The cost of the manufacturing equipment will increase significantly.

<Means for Solving the Problems> The present invention considers that in order to solve the above problems, it is necessary to directly raise the temperature of the resin hose portion in the hose body, and the following production method of the present invention is considered. I thought.

That is, a hose body made of a thermoplastic resin and a cylindrical rubber protector is provided on the hose, and the hose is provided with a base at both ends, and is formed in a straight tubular shape. The hose body is formed by heating the hose body, plasticizing the hose body, shaping the hose body into a predetermined bent shape, blowing air inside the hose body, and cooling and solidifying. A method of manufacturing a bent hose with a protector, wherein an electric resistance heating element layer is interposed between the resin hose portion and the protector, and the electric resistance heating element layer is energized through the base to form the electric resistance heating element layer. By raising the temperature, the hose portion is plasticized, and the hose body portion is shaped into a predetermined bent shape.

<Example> Hereinafter, the present invention will be described in more detail based on examples. The same members as those described in the conventional example are denoted by the same reference numerals, and description thereof will be partially omitted.

First Embodiment The manufacturing method of this embodiment includes (1) a step of forming the hose body 27, (2) a step of attaching the base 9, (3) a step of heating and forming the hose body 27, and (4) A) a cooling step.

(1) Step of Forming Hose Body 27 (FIG. 2) In this step, the hose body 27 is straight tubular with the electric resistance heating element layer 21 interposed between the resin hose 3 and the protector 5. Formed.

First, the resin hose portion 3 is extruded, and a braided layer (this layer becomes the electric resistance heating element layer 21) is formed on the peripheral surface thereof with a nichrome wire. Then, it is cut to a predetermined length. The molding material of the resin hose portion 3 is appropriately selected according to the substance through which the hose flows (for example, polyamide for fuel).

In order to reliably maintain the airtightness between the nipple 11 and the resin hose portion 3 of the base 9, as shown in the example of FIG.
It is preferable to eliminate the electric resistance heating element layer from both ends of the substrate.

Note that the electric resistance heating element layer 21
The resin hose portion 3 may be formed of any material as long as the resin hose portion 3 can generate plastic heat at a temperature higher than the softening temperature and plasticize the resin hose portion 3. As the electric resistance heating element layer 21,
A metal layer covering the entire peripheral surface of the resin hose portion 3 can also be used. In this case, the metal layer may be formed on the inner peripheral surface of protector 5.

When the hose body 27 is partially bent, the electric resistance heating element layer 21 is partially applied only to the portion to be bent.
May be formed.

The protector 5 is externally mounted on one objective of the resin hose portion 3 -the electric resistance heating element layer 21, and the hose body portion 27 is formed in a straight tubular shape.

The molding material of the protector 5 is appropriately selected according to the usage environment of the hose. For example, EPDM, CR, fluorine rubber, and silicone rubber are used. In the fuel hose, the protector 5 is made of silicone rubber so as to withstand the heat of the engine and the like.
Is formed. The protector 5 is formed by extrusion or injection.

In the protector 5, the enlarged diameter portions 5a and 5b at both ends are provided.
Is formed to wrap the sleeve 9 of the base 9. The reason why the enlarged diameter portion 5a on the left side in the figure is formed to be long in the axial direction is that the protector 5 needs to be shifted in the process of attaching the base 9 described below.

(2) Attaching process of base 9 (FIG. 3) The base 9 is composed of a nipple 11 and a sleeve 13. And first, cover the left end of the resin hose part 3 with the sleeve 13,
The periphery of the opening of the sleeve 13 and the hose body 27 are fixed with a chuck (not shown). At this time, the protector 5 is shifted to the right. Then, the nipple 11 is connected to the resin hose 3
To integrate the three.

Similarly, the base 9 is also attached to the right end of the hose body 27 (the state shown in FIG. 4). At this time, since the protector 5 needs to be shifted to the left, the left enlarged diameter portion 5a is extended in the axial direction.

The sleeve 13 is made of a conductive metal, and both ends of the electric resistance heating element layer 21 are connected to the sleeve 13.

(3) Heating and Forming Step of Hose Body 27 (FIG. 5) The hose formed in the state shown in FIG. Then, the sleeves 13 at both ends are connected to a power supply 33, and electricity is supplied to the electric resistance heating element layer 21. As a result, the electric resistance heating element layer 21 directly raises the temperature of the resin hose portion 3 to plasticize it, and the resin hose portion 3 is shaped into a shape along the cavity of the mold 31.

According to the study of the present inventor, in order to plasticize a polyamide hose portion 3 having a thickness of 1 mm and an outer diameter (diameter) of 8 mm,
It lasted 60-120 seconds.

This is (1/3) to (2/3) of the time conventionally required for plasticizing the resin hose portion 3.

When the bending radius of the hose body 27 becomes small, it is preferable that the resin hose portion 3 is plasticized in advance by supplying electricity to the electric resistance heating element layer 21 before setting it in the molding die 31.

(4) Step of Cooling and Solidifying Resin Hose Part 3 Next, air is blown to one of the bases 9 to cool the resin hose part 3 that has been heated to the plasticized state from the inside.
Thereby, the bent hose 1 shown in FIG. 1 is obtained.

According to the study of the present inventor, the resin hose portion 3 could be solidified by blowing air at 30 ° C. for 30 seconds.

This is 1/6 of the time conventionally required to solidify the resin hose part 3.

<Effects of the Invention> As described above, the present invention includes a hose body made of a thermoplastic resin hose and a tubular rubber protector, and caps are attached to both ends of the hose. By heating the hose body portion formed in a straight tube, the hose portion is plasticized, the hose body portion is shaped into a predetermined bent shape, and air is introduced into the hose portion. A method of manufacturing a bent hose with a protector formed by blowing and cooling and solidifying, wherein an electric resistance heating element layer is interposed between the resin hose portion and the protector, and the electric resistance heating element is passed through the base. By energizing the layer and raising the temperature of the electric resistance heating element layer, the hose portion is plasticized, and the hose body is shaped into a predetermined bent shape.

When the bent hose is formed in this manner, the resin hose portion can be directly heated when the hose body portion in a straight pipe state is plastically deformed.

Compared with the conventional manufacturing method in which the protector is heated from above, the protection is not interposed and the heat amount is probably smaller. Therefore, the time for plasticizing the resin hose portion is reduced.

Also, when cooling the resin hose portion, the temperature of the protector is not raised as a whole as in the conventional example (only the portion in contact with the electric resistance heating element layer is heated). The effect of heat on the surface is reduced. Therefore, the cooling time of the resin hose portion is also reduced.

As described above, according to the present invention, the productivity of the bent resin hose with the protector is improved.

However, on the other hand, it is undeniable that the material cost of the bent hose with the protector itself is improved due to the presence of the electric resistance heating element layer.

However, if the manufacturing time of the bent hose is significantly shortened, labor costs and the like are reduced, so that the increase in the material cost can be surpassed sufficiently.

[Brief description of the drawings]

FIG. 1 is a front view of a bent hose 1 with a protector according to the present invention. FIG. 2 is a front view of a straight tubular hose body 27 in the first embodiment, FIG. 3 is an explanatory view of a mounting process of the base 9, and FIG. 4 is a straight tube hose body provided with the base 9. FIG. 5 is an explanatory view of a process of bending the hose body 27, FIG. 6 is a front view of a conventional straight hose body 7, and FIG. Explanatory drawing of the process of bending. 1 ... bent hose, 3 ... resin hose part, 5 ... protector, 7,27 ... hose body part, 21 ... electric resistance heating element layer.

Claims (1)

(57) [Claims] 1. A hose having a hose body made of a thermoplastic resin and a cylindrical rubber protector provided outside the hose body, and a base attached to both ends of the hose part. The hose body is plasticized by heating the formed hose body, the hose body is formed into a predetermined bent shape, and air is blown into the hose to be cooled and solidified. A method of manufacturing a bent hose with a protector, wherein an electrical resistance heating element layer is interposed between the hose portion and the protector, and the electrical resistance heating element layer is energized through the base to generate the electrical resistance heating element. A method of manufacturing a bent hose with a protector, wherein the hose layer is plasticized by heating the body layer, and the hose body is shaped into a predetermined bent shape. .