JP2010096354A - Brake hose - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake hose 10 improving both characteristics of durability and expansion resistance (a volume expansion amount). <P>SOLUTION: The brake hose 10 includes an inner tube rubber layer 12 and an outer skin rubber layer 20, and it has at least two reinforcement layers comprising an upper thread layer 18 and a lower thread layer 14 between the inner tube rubber layer 12 and the outer skin rubber layer 20. In a lower thread 15 of the lower thread layer 14, a polyester thread is used with a tensile strength of ≥6.9 kg per unit digitex and a ductility of 2.6±1.0% under a load of 2.7g, and a braiding angle with respect to a hose axial direction is 59±2°. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a reinforcing hose having at least two reinforcing layers composed of an upper thread layer and a lower thread layer between an inner tube rubber layer and an outer rubber layer.

  Conventionally, among these types of reinforcing hoses, a brake hose used in an automobile is shown in FIG. FIG. 7 is a cross-sectional view showing a main part of a conventional brake hose 100. The brake hose 100 is formed by laminating rubber and fiber yarns in multiple layers because it needs to have high pressure resistance against brake hydraulic pressure. That is, the brake hose 100 is formed by laminating an inner pipe rubber layer 102, a lower thread layer 104, an intermediate rubber layer 106, an upper thread layer 108, and an outer rubber layer 110 that form a flow path 101 through which brake oil flows. It is comprised by doing.

  In the brake hose 100, fluid pressure is transmitted from the inner tube rubber layer 102 to the lower thread layer 104, the intermediate rubber layer 106, and the upper thread layer 108, and further to the outer rubber layer 110. Each layer has a restraining force that suppresses expansion against the pressure of the pressure fluid. At this time, each rubber layer of the inner tube rubber layer 102, the intermediate rubber layer 106, and the outer rubber layer 110 has high elasticity, so that only a slight restraint force is generated, and most of the rubber layers are formed by the lower thread layer 104 and the upper thread layer 108. Has the binding power of Therefore, increasing the restraining force generated by the reaction force accompanying the expansion of the lower thread layer 104 and the upper thread layer 108 increases the expansion resistance of the brake hose 100, that is, reduces the volume expansion amount. Increasing durability against repeated expansion and contraction of the 104 and the upper thread layer 108 improves the durability of the brake hose 100 itself. However, fiber yarns with high stretchability are excellent in durability, but poor in expansion resistance. Conversely, fiber yarns with low stretchability are excellent in expansion resistance but inferior in durability. That is, these two characteristics are contradictory.

  In order to achieve both such durability and expansion resistance, a polyester fiber having a high elastic modulus (high elasticity PET yarn) is used for the lower yarn layer 104, and durability is ensured, and the upper yarn layer 108 has a small elongation vinylon yarn. What reduced the volume expansion | swelling amount using is known (patent document 1). Also known is an attempt to improve durability and expansion resistance by braiding lower yarns made of thin fiber yarns to form a thin and dense reinforcing layer (Patent Document 2).

  However, in recent years, higher pressure resistance and expansion resistance have been required along with the increase in the pressure of automobile hydraulic devices, and depending on the change in the thread type of the lower thread layer 104 and the upper thread layer 108 as described above, Not enough properties have been obtained.

Japanese Patent No. 2692480 Japanese Patent No. 3003769

  The present invention has been made in view of such circumstances, and a brake having improved both durability and expansion resistance (volume expansion amount) characteristics by examining the knitting angle of the reinforcing yarn of the reinforcing layer. The purpose is to provide a hose.

The brake hose of the present invention made to solve the above problems is
In a reinforcing hose comprising at least two reinforcing layers composed of an upper thread layer and a lower thread layer between the inner tube rubber layer and the outer rubber layer,
The lower yarn layer uses a reinforcing yarn made of a polyester yarn having a tensile strength per unit decitex of 6.9 g or more and an elongation at a load of 2.7 g of 2.6 ± 1.0%. Is formed by braiding at a knitting angle of 59 ± 2 ° with respect to the hose axial direction.

  The fluid pressure of the reinforcing hose according to the present invention is transmitted from the inner tube rubber layer to the reinforcing layer and further to the outer rubber layer. At this time, the reinforcing layer acts so as to suppress volume expansion by a resistance force generated when the reinforcing yarn expands as the fluid pressure increases or decreases.

  As the reinforcing yarn, a polyester yarn having a tensile strength per unit decitex of 6.9 g or more and 2.6 ± 1.0% elongation under a load of 2.7 g (hereinafter referred to as high elasticity PET yarn) is used. Therefore, both durability against repeated load and low volume expansion can be achieved. In other words, normal PET has a tensile strength per unit decitex of 6.6 g or more and a characteristic value of elongation of 4.0 ± 1.0% at a load of 2.7 g. Since the elongation per fixed load is small with respect to the PET yarn, the volume expansion amount can be reduced. Further, since the lower yarn layer (or the upper yarn layer) uses polyester yarn instead of vinylon, it is excellent in fatigue resistance. Here, the unit decitex means the number of grams per 10,000 m of the filament yarn. The high-elasticity PET yarn preferably has a tensile strength per unit decitex of 6.9 g or more and an elongation at a load of 2.7 g of 2.6 ± 0.5%.

  In addition, as described above, the highly elastic PET yarn has a larger effect of suppressing the volume expansion amount than the normal PET yarn, but the volume expansion amount is further suppressed by setting the knitting angle of the reinforcing yarn to 59 ± 2 °. can do. The reason why the volume expansion amount can be reduced by setting the knitting angle in such a range will be described. The reinforcing layer is formed by winding reinforcing yarns around each other in the clockwise and counterclockwise directions on the outer periphery of the inner tube rubber layer. Here, the knitting angle of the reinforcing yarn means an inclination angle with respect to the hose axial direction. When the fluid pressure in the reinforcing hose rises, a force is applied to stretch the reinforcing yarn. This force acts on the expansion in the radial direction and the extension in the hose axial direction, but when the knitting angle is a static angle, that is, an angle of 54.44 °, these forces are balanced to increase the volume of the reinforcing hose. It is believed that the amount of expansion is most reduced. Therefore, in the conventional reinforcing hose, the fibers are knitted at the above-mentioned static angle or a value close to this.

  However, in a reinforcing hose using a highly elastic PET yarn and having a reinforcing layer embedded between the inner tube rubber layer and the outer rubber layer, the knitting angle is 59 ± 2 °, particularly preferably 59 ± 1 °, which is larger than the static angle. It has been found by the present inventor that the volume expansion amount can be reduced by setting. In other words, the knitting angle at which the volume expansion amount can be reduced most is the static angle (54.44 °) when geometrically examined, but it is larger than the static angle when actually applied to the reinforcing hose. ± 2 °. In view of these facts, the knitting angle is set in the above range.

  Here, in order to manufacture the reinforcing layer, for example, while extruding the inner tube extrudate forming the inner tube rubber layer by extrusion molding, braiding a reinforcing yarn on the inner tube rubber layer using a brader, and further on the reinforcing layer The outer rubber layer is formed by extrusion. Here, the knitting angle of the reinforcing layer can be set by the ratio between the pulling speed of the inner tube rubber layer and the rotation speed of the braider.

  Moreover, as a suitable aspect of the inner tube rubber layer, the thickness is preferably 0.6 ± 0.2 mm, and particularly preferably 0.6 ± 0.1 mm. Since the outer diameter can be reduced by reducing the thickness of the inner tube rubber layer, it can be braided tightly and tightly with a small amount of reinforcing yarn on the inner tube rubber layer. Can be reduced, and the volume expansion amount can be reduced. Here, the smaller the thickness of the inner tube rubber layer, the greater the effect. However, if the thickness is less than 0.4 mm, the inner tube rubber layer becomes difficult to be extruded or the pressure fluid is transmitted. It is preferable that

  Furthermore, the preferred embodiment of the reinforcing yarn uses a material whose thickness is 1100 ± 100 dtex, and this enables the reinforcing layer to be densely formed with a small outer diameter, so that the volume expansion amount can be reduced. .

It is the perspective view which fractured | ruptured a part of brake hose concerning the Example of this invention. It is a half sectional view of a brake hose. It is explanatory drawing explaining the knitting angle of a lower thread layer. It is explanatory drawing explaining a hose manufacturing apparatus. It is explanatory drawing explaining the result of having investigated the effect | action and effect of the brake hose. It is a graph explaining the relationship between a knitting angle and volume expansion amount. It is sectional drawing which shows the principal part of the conventional brake hose.

  In order to further clarify the configuration and operation of the present invention described above, preferred embodiments of the present invention will be described below.

(1) Schematic structure of brake hose 10 FIG. 1 shows an embodiment in which the reinforcing hose of the present invention is applied to the brake hose 10, a perspective view with a part thereof broken, and FIG. 2 is a half sectional view of the brake hose 10. . 1 and 2, a brake hose 10 is used to connect a master cylinder used for a hydraulic brake (not shown) and a hydraulic device on a tire side, and is laminated in five layers. Thus, it is configured to withstand the brake fluid pressure. That is, the brake hose 10 includes an inner tube rubber layer 12 having a flow path 11, a lower thread layer 14, an intermediate rubber layer 16, an upper thread layer 18, and an outer rubber layer 20, and a base 22 at the end. It is concluded by caulking.

(2) Configuration of each layer of the brake hose 10 The brake hose 10 is made of a material, a thickness, and a thickness of each layer in order to obtain characteristics such as pressure resistance, durability and expansion resistance that can withstand a brake fluid pressure up to 50 MPa. The knitting angle is determined.

(2) -1 Inner tube rubber layer 12
The inner tube rubber layer 12 is formed by extrusion using ethylene / propylene / diene copolymer rubber (EPDM), styrene / butadiene rubber copolymer (SBR) or the like mainly to obtain oil resistance. The thickness is 3.0 to 3.4 mm and the thickness is 0.4 to 0.8 mm. Here, if the thickness of the inner tube rubber layer is thin, the effect of reducing the volume expansion amount is large, but if it is less than 0.4 mm, extrusion molding becomes difficult or pressure fluid permeates, so 0.4 mm or more It is preferable that

(2) -2 Lower thread layer 14
The lower yarn layer 14 is formed by braiding the lower yarn 15 obtained by combining two or three high-elasticity PET yarns on the inner tube rubber layer 12 with 20 or 24 shots. The high elastic PET yarn is a polyester yarn having a tensile strength per unit decitex of 6.9 g or more and an elongation at a load of 2.7 g of 2.6 ± 1.0%, more preferably per unit decitex. A polyester yarn having a tensile strength of 6.9 g or more and an elongation at a load of 2.7 g of 2.6 ± 0.5% is used. The lower yarn 15 is formed by bundling 200 to 400 filament yarns. The lower yarn layer 14 is applied with an undercoat layer after bundling filament yarns, and then subjected to RFL treatment. Here, the RFL treatment means that an adhesive thin film acting as an adhesive mainly composed of resorcin, formaldehyde, latex resin and rubber latex is applied to the surface of the yarn. The lower thread layer 14 has a thickness of 0.55 to 0.95 mm, preferably 0.65 to 0.85 mm.

  Here, the knitting angle of the lower thread layer 14 is set to 59 ± 2 °, preferably 59 ± 1 °, in order to reduce the volume expansion. FIG. 3 is an explanatory view for explaining the knitting angle of the lower thread layer 14. As shown in FIG. 3, the lower thread layer 14 is configured by braiding the lower thread 15 on the inner tube rubber layer 12 in a spiral manner at a knitting angle θ. Here, the knitting angle θ refers to an angle formed by the lower thread 15 with respect to the hose axial direction. For example, when braiding the inner tube rubber layer with a braider while extruding, the inner tube rubber layer It can be changed by the ratio between the drawing speed and the rotation speed of the braider.

(2) -3 Intermediate rubber layer 16
The intermediate rubber layer 16 is a layer for preventing the lower thread layer 14 and the upper thread layer 18 from being displaced, and the rubber material is extruded onto the lower thread layer 14 or the sheet material 16A is placed on the lower thread layer 14. It is configured by winding or by applying rubber paste. As the rubber material, EPDM, isobutylene / isoprene copolymer (IIR), and natural rubber (NR) can be used. In this case, when EPDM and IIR and blended materials thereof are used, the heat resistance can be increased from the physical property values. The thickness of the intermediate rubber layer 16 is preferably 0.1 to 0.35 mm. That is, if the intermediate rubber layer 16 is less than 0.1 mm, it is too thin to be formed on the lower thread layer 14, while if it exceeds 0.35 mm, the thick intermediate rubber layer 16 becomes the lower thread. This is because it acts as an elastic layer that allows the displacement of the layer 14 and suppresses the displacement of the lower thread layer 14.

(2) -4 Upper thread layer 18
In the same manner as the lower thread 15, the upper thread layer 18 forms an upper thread 19 by RFL-treating a high-elasticity PET thread in which 200 to 400 filament threads are bundled and then combining two or three. The upper thread 19 is formed by braiding the intermediate rubber layer 16 with 20 or 24 strokes. Further, the knitting angle of the upper yarn layer 18 is preferably set to 59 ± 2 °, particularly 59 ± 1 °, in order to reduce the volume expansion amount, similarly to the lower yarn layer 14.

(2) -5 Outer rubber layer 20
The outer rubber layer 20 is formed of EPDM, a blend material of EPDM and CR, etc. mainly for obtaining ozone resistance, and has a thickness of 0.8 to 1.3 mm.

(3) Manufacturing method of brake hose 10 Next, the manufacturing method of the brake hose 10 is demonstrated. The brake hose 10 can be manufactured by a known method, that is, by performing a rubber extrusion process, a fiber yarn braiding process, and a vulcanization process.

(3) -1 Hose manufacturing apparatus 30
FIG. 4 is an explanatory view for explaining the hose manufacturing apparatus 30. In FIG. 4, the hose manufacturing apparatus 30 includes a first extrusion device 31, a first braiding device 32, an intermediate sheet forming device 34, a second braiding device 35, and a second extrusion device 37. Yes. The first extrusion device 31 is a device for forming the inner tube rubber layer 12 by extruding a rubber material. The first knitting device 32 includes a bobbin carrier attached to the drum 32a, and forms the lower yarn layer 14 by braiding the lower yarn 15 from the bobbin carrier onto the inner tube extrudate 12A. . The intermediate sheet forming device 34 is a device that feeds a sheet material 16 </ b> A for forming the intermediate rubber layer 16 from the roller onto the lower yarn layer 14 braided by the first braiding device 32. The second knitting device 35 has substantially the same configuration as that of the first knitting device 32, and includes a bobbin carrier mounted on the drum 35a, and on the intermediate rubber layer 16 while feeding the upper thread 19 from the bobbin carrier. This is an apparatus for forming the upper thread layer 18 by braiding. The second extrusion device 37 is a device that extrudes a rubber material to form the outer rubber layer 20.

(3) -2 Manufacturing Process of Brake Hose 10 Next, a series of manufacturing processes of the brake hose 10 by the hose manufacturing apparatus 30 will be described with reference to FIG. First, the inner tube rubber layer 12 is formed by extruding a rubber material by the first extrusion device 31. At this time, a mandrel (not shown) is inserted into the inner tube rubber layer 12. Subsequently, the lower thread layer 14 is formed by drawing the lower thread 15 from the bobbin and braiding the inner pipe rubber layer 12 while rotating the drum 32a of the first braiding device 32 on the extruded inner tube rubber layer 12. Form. In this case, for example, to braid the lower thread layer 14 with 20 strokes, the lower thread 15 is fed out from a total of 20 bobbins rotating in the opposite direction. Here, in order to set the knitting angle θ of the lower thread layer 14 to 59 ± 2 °, it can be set by the ratio between the drawing speed of the inner tube rubber layer 12 and the rotational speed of the drum 32a. Next, the intermediate rubber layer 16 is formed on the lower thread layer 14 by supplying the sheet material 16 </ b> A from the intermediate sheet forming device 34. Further, while rotating the drum 35 a of the second braiding device 35 on the intermediate rubber layer 16, the upper thread 19 is fed out from the bobbin and the upper thread layer 18 is braided on the intermediate rubber layer 16. The outer rubber layer 20 is formed on the upper thread layer 18 by extruding a rubber material from the second extrusion device 37.

  Subsequently, a vulcanization step is performed. As conditions of a vulcanization process, it sets at 120-170 ° C for 15-60 minutes. The upper thread layer 18 and the lower thread layer 14 that have been RFL-treated by heating in the vulcanization process are bonded to the inner tube rubber layer 12, the intermediate rubber layer 16, and the outer rubber layer 20. Thereby, the brake hose 10 is formed integrally.

(4) Action and Effect of Brake Hose (4) -1 Brake Hose Test Next, a brake hose according to the above example was prepared and examined for durability and expansion resistance (volume expansion amount). FIG. 5 shows the configuration and performance of Examples 1 and 2 and Comparative Examples 1 and 2 prepared as samples. Here, the brake hose was prepared so that the inner diameter was 3.1 to 3.2 mm and the outer diameter was 10.2 to 10.5 mm.

  Here, in Examples 1 and 2, the knitting angle θ of the lower yarn layer is 59 °, and the upper yarn layer and the lower yarn layer are made of highly elastic PET yarn. Here, the high-elasticity PET yarn of Example 1 is 1670 dtex, and the tensile strength of 1670 dtex is 11.5 kg or more, and the elongation at the time of 4.5 kg load is 2.6 ± 1.0%. In addition, Example 2 is a thin thread with a fiber thread thickness of 1100 dtex compared to Example 1, the tensile strength of 1100 dtex is 7.6 kg or more, and the elongation at a load of 3.0 kg is 2 .6 ± 1.0%. On the other hand, in Comparative Examples 1 and 2, the knitting angle θ of the lower thread layer is 56 ° or less, and in Comparative Example 1, the material of the upper thread layer and the lower thread layer is both PET. Then, it is an example of patent document 1 in which the lower thread layer used the highly elastic PET thread | yarn, and the material of the upper thread layer used the polyvinyl alcohol (PVA) thread | yarn.

(4) -1-1 Durability Test The durability test was performed by a repeated pressure test by actually flowing brake pressure oil through the brake hose. In other words, the brake hose was arranged along the same route as piped in an actual vehicle, and was implemented by a combination of repeated pressurization by brake fluid pressure and swinging and turning motions that imitates tire motion. As for the brake fluid pressure, pressurization of 0 MPa and 9.8 MPa was repeated at 0.7 Hz, rocking was performed at 2.5 Hz, turning was performed at 0.28 Hz, and the number of times of turning until the breakage was examined. As a result, it was found that the durability did not change even when the knitting angle was made larger than that of the comparative example and a high elastic PET yarn was used for both the lower yarn layer and the upper yarn layer.

(4) -1-2 Volume expansion amount test The volume expansion amount test is based on JIS2601, and the amount of change in the internal volume of the brake hose with a free length of 305 mm (1 foot) when the hydraulic pressure is increased at 10.3 MPa. It investigated by measuring. In the example, it was found that the volume expansion amount was reduced as compared with Comparative Examples 1 and 2.

(4) -2 Relationship between the knitting angle θ and the volume expansion amount Further, the relationship between the knitting angle θ and the volume expansion amount was further investigated. FIG. 6 is a graph for explaining the relationship between the knitting angle and the volume expansion amount. Here, for the brake hose, samples S1 to S6 in which the outer diameter is 10.2 mm, the knitting angle θ of the upper thread layer 18 is 59 °, and the knitting angle θ is changed are prepared, and the volume expansion amount thereof is examined. It was. As a result, it was found that the volume expansion amount decreased when the knitting angle θ exceeded 57 ° as in the samples S3 to S6. It was also found that the volume expansion increased when the knitting angle θ exceeded 61 °.

  The present invention is not limited to the above embodiment, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

  In the above embodiment, the brake hose has been described as the reinforcing hose. However, the present invention is not limited to this, and any hose for high pressure may be applied to a power steering hose for automobiles or a hydraulic hose for construction machinery.

DESCRIPTION OF SYMBOLS 10 ... Brake hose 11 ... Flow path 12 ... Inner pipe rubber layer 12A ... Inner pipe extrudate 14 ... Lower thread layer 15 ... Lower thread 16 ... Intermediate rubber layer 16A. ..Sheet material 18 ... Upper thread layer 19 ... Upper thread 20 ... Outer rubber layer 22 ... Base 30 ... Hose manufacturing equipment 31 ... First extrusion equipment 32 ... First Braiding device 32a ... Drum 34 ... Intermediate sheet forming device 35 ... Second braiding device 35a ... Drum 37 ... Second extrusion device

Claims (4)

In a reinforcing hose comprising at least two reinforcing layers composed of an upper thread layer and a lower thread layer between the inner tube rubber layer and the outer rubber layer,
The lower yarn layer uses a reinforcing yarn made of a polyester yarn having a tensile strength per unit decitex of 6.9 g or more and an elongation at a load of 2.7 g of 2.6 ± 1.0%. A reinforcing hose characterized by being braided with a braiding angle of 59 ± 2 ° with respect to the hose axial direction. The reinforcing hose according to claim 1,
The upper yarn layer uses a reinforcing yarn made of a polyester yarn having a tensile strength of 6.9 g or more per unit decitex and an elongation at a load of 2.7 g of 2.6 ± 1.0%. Reinforcement hose constructed by braiding the braid with a braiding angle of 59 ± 2 ° with respect to the hose axial direction. In the reinforcing hose according to claim 1 or 2,
A reinforcing hose in which the inner tube rubber layer has a thickness of 0.6 ± 0.2 mm. The reinforcing hose according to any one of claims 1 to 3,
The reinforcing hose has a thickness of 1100 ± 100 dtex.

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