JPH0330758B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a rubber hose with a connecting fitting used for a relatively large diameter suction hose for suctioning oil or the like.

[Prior Art] Generally, it is necessary to attach a connecting fitting to the end of a large diameter suction hose such as the one described above in order to connect the hoses to each other or to a device such as a suction pump. be.

There are various methods for installing connecting fittings, but the method of expanding the pipe diameter of connecting fittings, as described in Japanese Utility Model Application Publication No. 59-110492, is currently widely used because it is simple and efficient. A device for expanding the pipe diameter of a connecting fitting is also known, for example, from Japanese Patent Publication No. 54-19874.

In other words, the method for attaching a connecting fitting by expanding the pipe diameter is to fit an outer cylinder sleeve made of metal or plastic around the end of a vulcanized rubber hose, and insert the insert part of the connecting fitting into the end of the hose. In this state, the insert portion is expanded in the circumferential direction using a diameter expanding device to attach the connecting fitting.

However, in such conventional pipe diameter expansion methods, in order to obtain the desired pressure resistance, it is necessary to fit the outer sleeve around the outer periphery of the end of the rubber hose with as little gap as possible. It is necessary to change the outer cylinder sleeve. Even with this method, the airtightness between the rubber hose and the connecting fittings was still unstable, and there were large variations in pressure resistance.
In other words, suction hoses generally have about 50 to 300
Due to the large diameter (mm), it is difficult to use the extrusion method to manufacture such rubber hoses, so a band-shaped inner rubber is wound spirally around the outer circumference of the mandrel, and various types of fiber reinforcement layers, reinforcing steel wires, etc. After applying a reinforcing layer and wrapping a band-shaped outer rubber,
It is manufactured by vulcanization molding the entire product with wrapping cloth wrapped and tightened. Therefore, it is difficult to accurately regulate the outer diameter of rubber hoses, and it is common knowledge that even products of the same size may have slightly different outer diameters and wall thicknesses. When preparing the rubber hose and fitting the outer sleeve around the end of the rubber hose, the outer sleeve must be selected for each hose, and even with this troublesome work,
There was a drawback that the force with which the hose was pressed was considerably reduced by the insert part of the connecting fitting which was inserted into the hose to expand its diameter, and the outer cylindrical sleeve was fitted around the outer circumference of the hose, resulting in a loss of pressure resistance. .

In addition, since the outer sleeve is exposed and fixed on the outer periphery of the end of the rubber hose manufactured using the conventional inner diameter expansion method, the end of the outer sleeve may be damaged if it hits an obstacle when the hose is routed. There were also problems such as hoses tearing.

[Problems to be Solved by the Invention] In view of the above-mentioned conventional circumstances, the present invention connects connecting fittings by a tube diameter expansion method without using an external cylinder sleeve exposed on the outer periphery of the hose, and furthermore, connects the connecting fittings and the hose. It is an object of the present invention to provide a method for stably manufacturing a rubber hose with a connecting fitting that always has a constant pressure resistance by improving the pressure resistance.

[Means for solving the problems] The method for manufacturing a rubber hose with a connecting fitting of the present invention includes:
A supplementary rubber layer with good rubber flow during vulcanization is applied to the outer periphery of the outermost reinforcing layer on the end side of the inner rubber layer, and a rigid annular ring is inserted into the outer periphery of the end of this supplementary rubber layer. After applying an outer rubber layer to the outer periphery, the whole is vulcanized and molded, and the insert part of the connecting fitting is inserted into the end of the obtained rubber hose where the annular ring is embedded, and the insert part is expanded in the circumferential direction to connect. It is characterized by connecting the metal fitting to the end of the rubber hose.

[Function] In the present invention, a rigid annular ring is embedded in the end of the rubber hose in place of the conventional outer sleeve. The annular ring is preferably made of a rigid material such as steel that can withstand the compressive force caused by the expansion of the connecting fitting insert.Although there is no limit to the number of annular rings to be embedded, it is particularly preferable to place two long rings rather than one long ring.
Inserting short rings at intervals in the longitudinal direction has the advantage that the rings are less likely to peel off.

The annular ring is placed outside the outermost reinforcing layer,
Since a supplementary rubber layer is applied between the two that allows for good rubber flow during vulcanization, even if the outside diameter of the hose up to the supplementary rubber layer varies slightly and there is a gap between it and the annular ring, it will be supplemented during subsequent vulcanization. Since the rubber layer is swept away by the adjacent rubber layer and the gap is filled, the annular ring is embedded in the rubber without any gap. Natural rubber, SBR rubber, etc. can be used as supplementary rubber that exhibits such an effect.

In a rubber hose that is vulcanized with an annular ring embedded in the end in this way, there is no gap around the embedded annular ring, and the distance between the inner circumference of the hose and the inner circumference of the annular ring can always be kept constant. The connecting fitting insert and the annular ring inserted into the hose and expanded can always secure the end of the hose with a constant compressive force.

[Example] A specific example of manufacturing a rubber hose with a connecting fitting by the method of the present invention will be described with reference to FIGS. 1 to 3.

As shown in FIG. 1, NR rubber with a thickness of 3 mm was wound around the outer periphery of a mandrel (not shown) having an outer diameter of 203.2 mm to form the inner rubber layer 1, and the end portion of the hose in particular was made thicker by increasing the number of turns. The outer periphery of this inner rubber layer 1 is topped with a polyester reinforcing fiber layer 2, a reinforcing steel wire 3 with a diameter of 5.0 mm, and another reinforcing fiber layer 4.
and reinforcing steel wire 5 having a diameter of 4.0 mm were respectively wound helically in this order. A 2.0 mm thick SBR rubber was wound thereon to form an intermediate rubber layer 7, and a reinforcing fiber layer 8 of polyester topping was wrapped twice around the outer periphery of the intermediate rubber layer 7. Furthermore, the thickness is limited only to the outer periphery of the hose end.
3.0 mm of natural rubber is wrapped to form a supplementary rubber layer 9, and two annular rings 10 made of SUS41 with an inner diameter of 245 mm, a thickness of 3.0 mm, and a width (length) of 40 mm are placed around the outer circumference of the layer 9.
were inserted at intervals of 10 mm in the longitudinal direction. Next, the space between each annular ring 10 and the front and back are filled with SBR rubber to make the outer circumference of the surface smooth. Furthermore, after wrapping the polyester tightening cord 12 twice around the raised part 11 that becomes thicker toward the end, 4.0 thickness around outer circumference
An outer rubber layer 13 was formed by wrapping SBR rubber of mm in diameter. A wrapping cloth was wound spirally around the entire circumference of the outer rubber layer 13 in a conventional manner to restrain it, and the mixture was placed in a vulcanization can and vulcanized to obtain the rubber hose 14 shown in FIG.

Next, as shown in FIG. 2, the insert portion 16 of the connecting fitting 15 was inserted into the end of the rubber hose 14 described above. In the connecting fitting 15, the base 18 of the insert part 16 is brazed to the center hole of the flange part 17, and the inner diameter of the base 18 of the insert part 16 is 203.2 mm, which is the same as the inner diameter of the rubber hose 14.
The inner diameter of the portion 19 other than the base portion 18 is as small as 193 mm, and an annular groove with a serrated cross section is formed on the outer periphery over almost the entire length. Finally, the above-mentioned special public service
The insert portion 16 of the connecting fitting 15 was expanded to an inner diameter of 203.2 mm using a tube diameter expanding device such as that described in Japanese Patent No. 19874. As a result, the insert portion 16 of the connecting fitting 15 bites into the inner rubber layer 1, and the inner circumferential surface of the insert portion 16 becomes flush with the inner circumferential surface of the rubber hose 14. The rubber hose with the connecting fitting shown in FIG. was able to manufacture it. It was found that the pressure resistance of the rubber hoses with connecting fittings of the present invention produced in this manner was 70 Kgf/cm ² ±3 Kgf/cm ² , and that products having excellent pressure resistance could be stably obtained.

On the other hand, the inner diameter is attached to the outer circumference of a vulcanized rubber hose.
245mm, thickness 3.0mm, and width (length) 120mm
The conventional method was manufactured by inserting a single SUS41 outer sleeve with the inner diameter adjusted according to the outer diameter of the rubber hose, and then inserting and expanding the insert part of the connecting fitting into the end of the rubber hose in the same manner as above. The pressure resistance of the rubber hose with connection fittings is despite the fact that the length of the outer sleeve is longer than the two tubular rings of the present invention.
There was a large variation depending on the hose in the range of 55 to 72 Kgf/cm ² .

[Effects of the Invention] According to the present invention, it is possible to stably manufacture a rubber hose with a connecting fitting that improves the pressure resistance between the connecting fitting and the hose and always has a constant pressure resistance, and it is economical to prepare only one type of annular ring. and the manufacturing process becomes simple.

[Brief explanation of the drawing]

Figures 1 to 3 are schematic cross-sectional views showing the method of the present invention in the order of steps, with Figure 1 showing a vulcanized rubber hose, and Figure 2 showing a state in which a connecting fitting insert is inserted into this rubber hose. , and Fig. 3 respectively show a rubber hose connected to a connecting fitting by expanding the diameter of the insert portion. 1... Inner rubber layer, 9... Supplementary rubber layer, 10...
... Annular ring, 13 ... Outer rubber layer, 14 ... Rubber hose, 15 ... Connection fitting, 16 ... Insert part.

Claims (1)

[Claims] 1. A supplementary rubber layer with good rubber flow during vulcanization is provided on the outer periphery of the outermost reinforcing layer on the end side of the inner rubber layer, and a rigid annular layer is provided on the outer periphery of the end of this supplementary rubber layer. After inserting the ring and applying an outer rubber layer to the entire outer periphery, the whole is vulcanized and molded, and the insert part of the connecting fitting is inserted into the end of the thus obtained rubber hose where the annular ring is embedded, and the insert part A method for manufacturing a rubber hose with a connecting fitting, characterized in that the connecting fitting is expanded in the circumferential direction to connect the connecting fitting to an end of the rubber hose. 2. The method for manufacturing a rubber hose with a connecting fitting according to claim 1, characterized in that two rigid annular rings are inserted at an interval in the longitudinal direction on the outer periphery of the end of the supplementary rubber layer.