JPH059584Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention is applicable to a hose with a fitting used for delivery or suction and suction delivery of gas, liquid, slurry, powder, etc.
In particular, the present invention relates to an improvement in a hose with a fitting that airtightly connects a fitting to a portion of the hose cut to an arbitrary length.

[Prior art] Traditionally, hose fittings have been fixed by vulcanizing and adhering the metal fittings and rubber, which are often found in rubber hoses, or by cutting the hose to a desired length after vulcanization and attaching the fittings. There are methods for mounting, and the latter method, which is the subject of the present invention, can be further broadly classified into the following three types.

The band tightening type uses a tightening fitting to tighten the outer circumference of the hose at the insertion part of the hose fitting, the squeeze tightening type inserts a cylindrical fitting onto the outer circumference of the hose and tightens it evenly with pressure, and the outer cylindrical fitting is tightened with a tightening fitting. It is an expansion tightening type that is inserted into the outer periphery and expands the rear inner cylindrical metal fitting.

All of them deform or tension only one of the inner or outer cylinder or band of the hose, and they have in common that they always apply deformation or tension to only one of the inner and outer cylinders or bands.

[Problems to be solved by the invention] However, all hoses with fittings have the following problems.

First of all, (a) the deformation or tension is applied from either the inside or the outside, so one of the fittings that make up the inner or outer cylinder does not deform, so the amount of distortion is different between the inside and outside of the hose. , uniform airtightness cannot be obtained. Furthermore, (b) since only one fitting is deformed, the amount of deformation of the fitting itself is small, and therefore the degree of deformation given to the hose must also be small, so in order to obtain high airtightness, the hose body must be Must be highly rigid. That is, generally, it is difficult to obtain airtightness unless the hose has a large wall thickness.

Regarding this point, for example, regarding (a), the fitting length with the hose may be increased to improve airtightness, or a spiral protrusion may be added to one or both fittings to prevent partial deformation. Countermeasures have been taken, such as providing a groove or changing the thickness of the insertion cylinder into a gentle curve. In addition, in (b),
In cases where the rigidity of the hose is insufficient, measures have been taken such as providing a reinforcing body at the fitting fitting part to temporarily increase the rigidity of the hose.

However, all of the improvement measures required a longer fitting length or a special shape treatment, which caused problems.

The purpose of this invention is to maintain sufficient airtightness without increasing the mating length or special shape treatment.
Another object of the present invention is to provide a hose with a spout having sufficient tightening properties even when the hose is of low rigidity in a thick groove.

[Means for solving the problem] Generally, when obtaining airtightness for a thin-walled and low-rigidity hose, an inner cylinder having an outer diameter close to the inner diameter of the hose is inserted and the outer cylinder is crimped. Since the amount by which the hose is compressed cannot be large enough, the plastic deformation range of the metal outer cylinder cannot be reached.

Therefore, for such thin-walled hoses, the method of enlarging the inner cylinder is more often used.

However, even in this case, if the outer cylinder is fixed and does not deform itself, the inner cylinder cannot reach the plastic deformation region as in the former case.

Therefore, if the metal fitting is plastically deformed only from one side as in the conventional technology, it is not possible to sufficiently tighten the hose, and if the metal fitting is deformed to the extent of plastic deformation, the hose itself will exceed the compression limit. .

In addition, the most stable airtightness and dimensional stability can be obtained when the plastic deformation of the fitting starts from the state in which it is in contact with the hose, but in this method, in which the inner cylinder is expanded and the outer cylinder is fixed, the plastic deformation of the inner cylinder When the hose is installed at a position close to the maximum deformation range and hose compression begins, the expansion stress applied to the inner cylinder varies, resulting in uniform airtightness, metal fitting wall thickness, and hose wall thickness. It is difficult.

Therefore, in the present invention, an inner cylinder having an outer diameter slightly smaller than the inner diameter of the hose and an outer cylinder having an inner diameter slightly larger than the outside diameter of the hose are expanded together with the hose by an expanding force applied to the inner peripheral surface of the inner cylinder. At the same time, the structure was adopted as a hoss with a fitting that can simultaneously expand the inner and outer cylinders and tighten them by plastic deformation.

That is, the inner tube and the outer tube are installed close to the inner and outer diameters of the hose, respectively, and the entire hose fitting portion is expanded from inside the inner tube without fixing the outer tube. At this time, at the initial stage of expansion of the inner cylinder, it comes into contact with the inner diameter side of the hose, and immediately the outer side of the hose comes into contact with the inner diameter side of the outer cylinder. By continuing to maintain the inner cylinder expanding force, the hoses fitted to the outside of the inner cylinder and the inside of the outer cylinder are gradually compressed, and the inner cylinder and the outer cylinder are plastically deformed.

[Function] Therefore, according to the present invention, the hose is not excessively deformed and compressed, and the inner and outer cylinders can be processed in the most stable deformation region, so that the airtightness of the hose depends on the dimensions of the fitting. Stability can also be improved. In addition, since both the inner and outer cylinders are initially arranged in close proximity to the hose, eccentric arrangement of the inner cylinder, hose, and outer cylinder does not occur. In addition, since the inner and outer cylinders deform at the same time as the hose, there is little misalignment between the three parts and a uniform airtight pressure is maintained.

[Example] For example, as shown in the drawing, 1 has an inner diameter ID ₁ of 100 mm,
A cylindrical rubber hose 1 has an outer diameter OD ₁ of 106 mm, a wall thickness T ₁ of 3 mm, and has a single layer of nylon cord inside, and a cap fitting MF is installed at the end thereof. For the fitting MF, the outer diameter OD ₂ is the inner diameter of hose 1.
Inner cylinder 2 is 99mm, which is 1mm smaller than ID ₁ , and inner diameter ID ₂ is 93mm, and inner diameter ID ₃ is 1mm smaller than hose outer diameter OD ₁ .
It consists of an outer cylinder 3 with a large diameter of 107 mm and an outer diameter OD ₃ of 113 mm.

Now here, along with this inner cylinder 2, the hose 1 and the outer cylinder 3
When expanded and compressed to the hose's allowable compression rate of 30%, the outer diameter OD ₂ of the inner cylinder 2 is 106 mm, and the inner diameter ID of the outer cylinder 3.
is 110mm, wall thickness T ₁ is 2mm, and outer diameter of outer cylinder 3 is OD ₃
is 116 mm, the inner diameter ID ₂ of the inner cylinder 2 is 100 mm, and the expansion ends when the inner diameter ID ₂ of the inner cylinder 2 becomes the same as the original hose inner diameter ID ₁ . Depending on the material of the cap MF, it is also possible to temporarily increase the enlarged diameter and finally set it to the above dimensions.

Next, we confirmed that the rubber hose with the cap MF fastened to both ends would break by pulling the gap between both caps MF, and found that the designed rupture strength of the hose body was
Retention of 90% or more was approved.

Furthermore, when a blind flange was attached to the double-end fitting MF and a pressure fatigue test was repeated at water pressures of 20Kg/cm ² and 0Kg/cm ² , it was possible to perform the test over 1 million times without any abnormalities.

On the other hand, in the case of a hose that is connected using the conventional method of expanding the inner cylinder and fixing the outer cylinder, the inner cylinder, hose,
When the outer cylinder was made to have the same dimensions and the same material as those of this example, and the inner cylinder was expanded until it was plastically deformed, the compression ratio of the hose exceeded 70% and the hose broke. Similarly, when the conventional method of fixing the inner cylinder and tightening the outer cylinder was used, the hose also broke.

Note that this invention is not limited to the above embodiments. For example, it can be fully used for thick-walled hoses.

[Effects of the invention] As mentioned above, this invention is a hose with a fitting that expands the inner and outer cylinders at the same time, so even if the hose is bent or tensile force is concentrated near the fitting, damage will not occur. Since the hose is not subjected to excessive compression or deformation, its durability is significantly improved and it can be used for a long period of time. In addition, even a particularly thin-walled hose with a cap fitting exhibits stable high airtightness and high dimensional stability, we were able to provide a practical hose with a cap fitting that is easy to install and inexpensive.

[Brief explanation of drawings]

The drawing is a half sectional view showing an embodiment of this invention. 1... Hose, MF... Fitting, 2... Inner cylinder,
3...Outer cylinder, ID ₁ ...Hose inner diameter, OD ₁ ...Hose outer diameter, ID ₂ ...Inner cylinder inner diameter, OD ₂ ...Inner cylinder outer diameter,
ID ₃ : Outer cylinder inner diameter, OD ₃ : Outer cylinder outer diameter.

Claims (1)

[Scope of utility model registration request] A hose with a cap, in which a cap consisting of an inner tube and an outer tube is attached to the end of a cylindrical hose, sandwiching the hose, has an inner tube with an outer diameter slightly smaller than the inner diameter of the hose. A joint that simultaneously expands the inner and outer tubes, characterized in that an outer tube having an inner diameter slightly larger than the outer diameter is simultaneously plastically deformed and fastened together with the hose by an expanding force applied to the inner peripheral surface of the inner tube. Comes with a hose.