JPS5997380A - Resin hose for high pressure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-pressure resin hose with improved fatigue resistance.

Conventionally, fiber-reinforced high-pressure resin hoses for hydraulic pressure, such as ISO3
949-1980, SAE 100R7, SAE 10
In a resin hose that complies with standards such as 0R8, when there are two or more fiber-reinforced layers, the fiber-reinforced layers are in direct contact with each other, as shown in FIG. That is, in FIG. 1, reference numeral 1 is a resin hose, which has a plurality of reinforcing layers 6 and 4 applied to the outside of an inner tube 2, and a single layer 5 of an exterior cover is placed on top of the reinforcing layers 6 and 4. . A thermoplastic resin material such as polyester, polyamide, polyurethane, etc. is used for the inner tube 2, and an outer cover layer 5 is used.
Polyester and polyamide.

Resins such as polyurethane, polyolefin, and polyvinyl chloride are used. The reinforcing layers 6, 4 serve, for example, as reinforcement layers for liquid pressure resistance, and are made of organic fiber braids and spirals or wire braids and spirals. The number of reinforcing layers increases to two or three layers depending on the pressure resistance.

Because the reinforcing layers 6 and 4 are in direct contact with each other, conventional resin hoses are prone to friction between the reinforcing layers in places where there is a lot of movement, such as parts of bending pulleys, resulting in fiber fatigue and breakage. There was a problem with getting there.

In addition, in recent years, as forklifts and construction machinery have become more sophisticated, the high-pressure resin hoses used in these hydraulic devices and hydraulic circuits are required to have significantly improved durability and longevity. It's coming.

The present invention has been made in view of the above circumstances, and aims to reduce fatigue of reinforcing materials caused by rubbing between reinforcing layers due to changes in internal pressure, movement of the hose, bending, etc. in high-pressure resin hoses. This is the purpose.

For this reason, the present invention is characterized in that in a resin hose formed by applying two or more reinforcing layers on the outside of an inner tube made of synthetic resin, an adhesive layer is provided between each reinforcing layer, and the reinforcing layers are bonded together. shall be. Since the resin hose of the present invention has improved fatigue resistance, it can be used as a hydraulic hose for forklifts, etc., and is particularly used in areas where the hose moves a lot and is easily fatigued.

Embodiments of the present invention will be described below with reference to the drawings. Note that in FIG. 2, the same parts as in FIG. 1 are represented by the same numbers.

FIG. 2 shows an embodiment of the present invention. In this figure, an adhesive layer a is provided between the reinforcing layers 6 and 4, and thereby the reinforcing layers 6 and 4 are bonded together. ing.

The material of the adhesive layer a is not particularly limited, and may be a general rubber adhesive, such as a natural rubber adhesive, a synthetic com-based adhesive, especially one based on chlorinated rubber, NBR, phenol modification, etc., or a synthetic rubber adhesive.゛Synthetic resin adhesives, such as polyurethane and epoxy.

Either acrylic type, unsaturated polyester type, etc. may be used. To provide this adhesive layer-a, for example, the above-mentioned adhesive may be applied onto the reinforcing layer 6.

In addition, the thickness of the adhesive layer a is 0.001 mm to Q, 3 from the viewpoint of durability, manufacturing cost, and flexibility of the hose.
Preferably, it is mm. In addition, the reinforcing layer 6.4 includes:
In addition to conventional fibers such as nylon and polyester, Kevlar fibers and the like can be used.

The resin hose 1 according to the present invention has two or more reinforcing layers laminated, but even if the reinforcing layer is one layer, each outer cover layer 5 is made of braided or woven fabric of fibers or wires. This also includes cases where fatigue is likely to occur between layers. In addition, instead of the adhesive layer a, it may be possible to simply insert a film having rubber elasticity, such as a crosslinked rubber sheet or a resin film such as polyester, between the reinforcing layers, but in this case, the durability fatigue effect will be improved to some extent. However, the fatigue resistance is lower than that when the adhesive layer a is provided.

Examples and comparative examples are illustrated below.

EXAMPLES AND COMPARATIVE EXAMPLES Burst pressure tests and durability tests were conducted on resin hoses having the structures shown in FIGS. 1 and 2. The results are shown in Table 1 below. The resin hose 1 is made of a thermoplastic polyester elastomer for the inner tube 2, a polyester fiber braided layer for the reinforcing layers 6 and 4, and a thermoplastic polyurethane elastomer for the outer cover layer 5.

The inner diameter of the hose is φ9.5 mm.

In Table 1, in Example 1, a phenolic resin cross-linked adhesive mainly composed of NBR+chlorinated rubber was used as the adhesive layer a (hardness of adhesive after curing JISA65).

In Example 2, a polyurethane adhesive was thinly disposed as the adhesive layer 4 (hardness of the adhesive after curing: Shore D75).

In Example 3, the adhesive layer of Example 2 was provided thicker. In Example 4, the adhesive layer of Example 1 was provided thicker. Further, Comparative Example 1 is a conventional resin hose without adhesive layer a. In Comparative Example 2, a vulcanized rubber sheet was used, and in Comparative Example 3, a polyester film was provided as an intermediate layer instead of the adhesive layer a, and this intermediate layer was not adhered to the reinforcing layers 6 and 4. .

In addition, the thickness of the adhesive layer in Table 1 is the average thickness of the adhesive layer applied on the reinforcing layer 6, which is determined from the weight of the adhesive applied on the reinforcing layer B. .

(Margins below this page) (1) Burst pressure test According to the method specified in JIS K 6330.

(2) Durability test Corexing test and SAE in which the hose is hung on a pulley, a tensile load is applied to the hose, swinging is repeatedly applied in the length direction, and a part of the pulley is repeatedly bent and stretched.
At the same time, a hydraulic impact test was conducted in which the hose was repeatedly subjected to hydraulic impact pressure in accordance with the 100 R7 standard. The test conditions are as follows.

Pulley diameter (related) 100 Load (Kgf) 15 Width (+++m) 150 Width cycle (c, p, m) 50 Impact pressure (square wave)
(Kgf, 4F) 240 ditto cycles (c,
p, m) 70 oil temperature (°C)
93 As is clear from Table 1, the reinforcement layer of the conventional hose of Comparative Example 1 fatigued quickly, and the number of flexing cycles was 1.
The hose was destroyed after 20,000 cycles. This hose has a durability of more than 500,000 times in a hydraulic impact test at the same pressure. The hoses according to the present invention of Examples 1 to 3 have durability that is more than 400,000 times, which is about four times more than that of conventional hoses. Example 4 is a hose according to the invention, but 17
This shows that the effect of the present invention decreases when the adhesive layer becomes thicker, such as 0.5 mm. Comparative Examples 2 and 3 are each 23
210,000 times, which is better than the conventional hose, but inferior to Examples 1 to 3.

As described above, the resin hose of the present invention has the effect of effectively preventing fatigue due to rubbing between the reinforcing layers during use by providing an adhesive layer between the reinforcing layers. Therefore, this resin hose is suitable for use in places where there is a lot of movement, such as sliding parts or repeated bending, and can therefore be used in hydraulic circuits of forklifts, mini construction machines, etc.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view of an example of a conventional high pressure resin hose, and FIG. 2 is a partially cutaway perspective view of an example of the high pressure resin hose of the present invention. 1... Resin hose, 2... Inner tube, 6, 4.
... Reinforcement layer, 5... One layer of exterior cover, a... Adhesive layer. Agent: Patent Attorney Shin Ogawa - Patent Attorney, Ken Teru Noguchi Patent Attorney: Kazuhiko Saishita

Claims (1)

[Claims] A high-pressure resin hose comprising two or more reinforcing layers on the outside of an inner tube made of synthetic resin, characterized in that an adhesive layer is provided between each reinforcing layer and the reinforcing layers are bonded together. .