JP2008248943A - Heat-resistant hose - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the fatigue resistance of a heat-resistant hose reinforced by a reinforcement yarn layer. <P>SOLUTION: This heat-resistant hose 10 is connected to a turbocharger. The heat-resistant hose comprises: a first inner surface rubber layer 12 having a flow passage 12a; a second inner surface rubber layer 14; the reinforcement yarn layer 16; and an outer surface rubber layer 18. The first inner surface rubber layer 12 is formed of a fluorine compound rubber (FKM). The second inner surface rubber layer 14 and the outer surface rubber layer 18 are formed of a silicone rubber and vulcanized/adhered to enhance the heat resistance and the fatigue resistance. The reinforcement yarn layer 16 is formed by braiding the reinforcement yarn of aramid resin onto the second inner surface rubber layer 14. From the view point of securing the heat resistance and fatigue resistance, the silicone rubber of the second inner surface rubber layer 14 and the outer surface rubber layer 18 has an elongation of 120-250% under the environment of 180°C. For driving the reinforcement yarns, the reinforcement yarns of 2500-4000 dtex in fineness are used and the number of drivings of the reinforcement yarns is 64-76. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat-resistant hose that is used in automobile engines and the like for circulating a high-temperature gas.

  Conventionally, this type of heat-resistant hose has been widely used in vehicles and the like. For example, in an engine equipped with a turbocharger, it is used as a hose for sending intake gas supplied by the turbocharger to the intake pipe side of the engine. Yes. In order to ensure the durability of such a hose, it is usual to construct the hose in multiple layers and embed a reinforcing yarn layer between the layers of the hose. In addition, in order to ensure resistance to high-temperature and high-pressure intake gas passing therethrough, silicon rubber is being adopted as a hose material (see Patent Document 1).

JP 2000-193152 A

  In recent years, as the function of the engine improves, intake at a higher boost pressure is required, and the frequency of boosting tends to increase. For this reason, a further improvement in performance has been demanded for the heat resistant hose for sending the intake gas along with the improvement of the engine function. Although the heat resistant hose proposed in the above-mentioned patent document brings about an improvement in heat resistance, it has not been able to cope with such a demand, and it has been necessary to improve the hose performance in terms of fatigue resistance. In this case, if the number of reinforcement yarns driven in the reinforcing yarn layer is increased, the pressurization durability is increased. However, the increase in the number of implantations is not enough to improve the fatigue resistance.

  The present invention has been made to solve the above-described problems, and an object thereof is to improve the fatigue resistance of a heat-resistant hose reinforced with a reinforcing yarn layer.

  In order to achieve this object, the heat-resistant hose of the present invention employs the following configuration.

[Application 1]
A heat-resistant hose,
A first inner rubber layer that is formed using a fluorine compound-based rubber and is located on the innermost hose side of the hose to form the fluid flow path;
A second inner rubber layer laminated on the outer periphery of the first inner rubber layer and formed using silicon rubber;
A reinforcing yarn layer formed by winding a reinforcing yarn on the second inner rubber layer;
An outer rubber layer formed on the reinforcing yarn layer and formed using silicon rubber;
The silicon rubber of the second inner rubber layer and the outer rubber layer has an elongation in an environment of 180 ° C. of 120 to 250%,
The gist of the reinforcing yarn layer is formed by winding the reinforcing yarn having a fineness of 2500 to 4000 dtex with a driving number of 64 to 76 strokes.

  The heat-resistant hose having the above-described configuration includes a second inner rubber layer, a reinforcing yarn layer, and an outer rubber layer sequentially laminated on the outer peripheral side of the first inner rubber layer having a flow path for flowing a high-temperature gas fluid. And while increasing the durability by increasing the fineness of the reinforcing yarn and the number of driving in the reinforcing yarn layer over the existing hose, in the second inner rubber layer / outer rubber layer of silicon rubber sandwiching the reinforcing yarn layer up and down, While exhibiting heat resistance against high-temperature gas fluids, fatigue resistance is improved by increasing the elongation in a high-temperature environment as compared to existing hoses. Examples of the fluorine compound rubber forming the first inner rubber layer include vinylidene fluoride / hexafluoropropylene / tetrafluoroethylene copolymer: FKM. Further, the fineness of 2500 to 4000 dtex that defines the reinforcing yarn used for the reinforcing yarn layer is not limited to the short fiber of this fineness, and the fineness of the combined yarn of two fibers having a fineness of 1700 dtex or 1200 dtex of It may be the fineness of a combined yarn of three fineness fibers.

  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. FIG. 1 is a perspective view schematically showing each layer having a heat-resistant hose 10 according to an embodiment of the present invention in a broken state. As shown in FIG. 1, a heat-resistant hose 10 of this embodiment is a hose that connects a turbocharger of an automobile engine (not shown) and an intake pipe, and has a hose structure laminated in four layers. That is, the heat resistant hose 10 includes the first inner rubber layer 12 having the flow path 12a, the second inner rubber layer 14, the reinforcing yarn layer 16, and the outer rubber layer 18. As will be described later, the heat resistant hose 10 has a fatigue resistance of 100,000 times or more in an extension repeated test in which its length is extended by 50%, and a resistance of 1,000,000 times or more in a pressure repeated test in which a pressure of 300 KPa is repeatedly applied. In order to obtain fatigue, the material properties of the second inner rubber layer 14, the outer rubber layer 18 and the reinforcing yarn layer 16 and the reinforcing yarn driving property of the reinforcing yarn layer 16 are determined.

  That is, the first inner rubber layer 12 is made of a fluorine compound rubber (FKM) mainly for obtaining shape retention and oil penetration resistance. Here, shape retainability refers to the difficulty of crushing due to its own weight when the extruded body is formed in a tubular shape. Further, the second inner rubber layer 14 and the outer rubber layer 18 are both made of silicon rubber in order to improve heat resistance and fatigue resistance, and thus are vulcanized and bonded. Further, the reinforcing yarn layer 16 is formed to increase pressure resistance, and is formed by braiding a reinforcing yarn such as an aramid resin or aromatic polyamide on the second inner rubber layer 14. At the time of driving, a reinforcing yarn having a fineness of 2500 to 4000 dtex is wound at a driving number of 64 to 76.

  The thickness of each layer of the heat resistant hose 10 is also determined in consideration of heat resistance, oil penetration resistance, etc. For example, the inner diameter φ of the heat resistant hose 10 is 30 to 70 mm, and the wall thickness t is 4 to 8 mm. In some cases, the second inner rubber layer 14 may be 2 to 4 mm, the reinforcing yarn layer 16 may be 0.1 to 1 mm, and the outer rubber layer 18 may be 2 to 4 mm. In addition, about the 1st inner surface rubber layer 12, in order to ensure the shape retainability mentioned above, it was set as the thickness of about 0.25 mm.

  Next, the manufacturing method of the heat resistant hose 10 is demonstrated. The heat-resistant hose 10 can be manufactured by a known method, that is, by performing a rubber extrusion step, a reinforcing yarn winding step, and a vulcanization step. FIG. 2 is an explanatory diagram for explaining the hose manufacturing apparatus 30.

  In FIG. 2, the hose manufacturing apparatus 30 includes a first extruder 40, a blade apparatus 50, and a second extruder 60. The first extruder 40 is an apparatus for forming the extruded body 20A (the first inner rubber layer 12 and the second inner rubber layer 14) by co-extruding a rubber material. The blade device 50 is a device for forming the reinforcing yarn layer 16 on the extruded body 20A. The blade device 50 includes a bobbin carrier (not shown) attached to the drum 52, and the extruded body while feeding the reinforcing yarn 16a from the bobbin carrier. This is an apparatus for forming the reinforcing yarn layer 16 by bladed on 20A. The second extruder 60 is a device for forming the outer rubber layer 18, and the outer rubber layer 18 is formed by extruding a rubber material from the outer tube pushing portion 61.

  Next, a series of manufacturing steps of the heat-resistant hose 10 by the hose manufacturing apparatus 30 will be described with reference to FIG. By extruding a fluorine compound rubber and silicon rubber on the same axis from the first extruder 40, a two-layer cylindrical extrudate 20A is formed. When the extruded body 20A is extruded, the mandrel Md is inserted into the space 20a that forms the flow path of the extruded body 20A.

  At the time of the coaxial extrusion, the silicon rubber having a property that the elongation in an environment of 180 ° C. becomes 120 to 250% is supplied to the first extruder 40 and extruded after completion of the hose. If this elongation is in the range of 120 to 250%, it is possible to cope with the expansion of the hose diameter accompanying the supply of pressurized fluid into the hose and to ensure the resilience of the hose diameter.

  Subsequently, the extruded body 20A is sent to the blade device 50, and the reinforcing yarn 16a is fed out from the bobbin by the rotation of the drum 52 of the blade device 50, whereby the reinforcing yarn layer 16 is formed on the extruded body 20A. That is, the reinforcing yarn 16a is wound around the outer periphery of the extruded body 20A in a state where the extruded body 20A immediately after being extruded by the first extruder 40 is supported by the mandrel Md, and the reinforcing yarn layer 16 is formed. At this time, the extruded body 20A is not crushed because it is supported by the mandrel Md.

  When the reinforcing yarn 16a is driven by the blade device 50, the reinforcing yarn having a fineness of 2500 to 4000 dtex is wound with a driving number of 64 to 76 strokes. More specifically, one reinforcing yarn having a fineness of 2500 to 4000 dtex is wound at a driving number of 64 to 76, and a composite yarn obtained by combining two fibers having a fineness of 1700 dtex is used as a reinforcing yarn. Winding is performed at a driving number of 64 to 76 using a combined yarn of three fibers having a fineness of 1200 dtex as a reinforcing yarn. As for the number of times of driving, the blade devices 50 may be provided in multiple rows so that the driving of 32 strokes is performed twice.

  Next, silicon rubber for forming the outer rubber layer 18 is laminated on the reinforcing yarn layer 16 by the second extruder 60. That is, the rubber material for forming the outer rubber layer 18 is supplied directly onto the reinforcing yarn layer 16.

  Subsequently, a vulcanization step is performed. In the vulcanization step, secondary vulcanization at 150 to 170 ° C. for 4 to 12 hours was performed after primary vulcanization at 150 to 170 ° C. for 20 to 60 minutes. By this vulcanization step, the first inner rubber layer 12, the second inner rubber layer 14, and the outer rubber layer 18 are joined by performing normal vulcanization adhesion. Thereby, the heat resistant hose 10 is integrally formed.

  In the manufacturing method of the heat resistant hose 10 according to the above embodiment, the first inner rubber layer 12 of the extruded body 20A extruded by the first extruder 40 is formed of a fluorine compound rubber, so that the mechanical strength is increased. Therefore, it is hard to be crushed by its own weight and shape retention is improved. For this reason, the mandrel Md can be inserted into the extruded body 20A immediately after extrusion, and the reinforcing yarn 16a can be wound by the blade device 50 while the extruded body 20A is supported by the mandrel Md.

  Next, performance verification of the heat resistant hose 10 of the present embodiment will be described. FIG. 3 is an explanatory diagram showing the state of a durability test against repeated stretching under a high temperature environment. As shown in the figure, in this repeated stretch durability test, a strip-shaped test piece (thickness 2 mm) suitable for a test with a tensile tester was prepared. Then, the test piece is fixed to the upper and lower holding jigs HJ of the tensile tester, tension is applied, and the lower holding jig HJ is reciprocated up and down repeatedly. Thereby, the sample piece repeatedly takes the state where the measurement site full length LS excluding both ends is extended by S% and the state of the original full length LS. And this elongation rate S was set to 3 steps, 50%, 75%, and 100%, and the extension repetition durability test in each elongation rate was measured about the example and the comparative example.

  In this case, the test piece of Example has a strip shape of a sheet having a thickness of 2 mm prepared by using the above-described silicon rubber having the above-described properties for forming the second inner rubber layer 14 and the outer rubber layer 18 under the above vulcanization conditions. It is punched and has no reinforcing yarn. The test piece of the comparative example is a sheet of 2 mm thick punched out from a conventional 60% (under 180 ° C environment) silicone rubber with existing vulcanization conditions. And has no reinforcing yarn. That is, the example test piece and the comparative example test piece differ in the properties of the silicon rubber of the second inner rubber layer 14 and the outer rubber layer 18 in the heat resistant hose. The durability test was performed in a high temperature environment of 200 ° C. FIG. 4 is a graph showing a test result of an extension repeated durability test in a high temperature environment.

  As shown in the figure, in the test piece of the comparative example, the test piece broke after repeated repetition of less than 100 times as a result of the repeated stretch durability test at a stretch rate of 50% in a high temperature environment of 200 ° C. At 75%, test piece breakage occurred 20 times, and 100% at several times. On the other hand, in the test piece of the example, the resistance against the extension repetition of a little less than 1 million times is seen in the extension repetition at the extension rate of 50%, the resistance exceeding 75 times even at 75%, and about 300 times even at 100%. There was resistance. In this embodiment, it is assumed that the turbocharger of the automobile engine and the intake pipe are connected. Therefore, when evaluating the durability against repeated stretching (fatigue resistance against repeated stretching), 50% repeated stretching Therefore, it was demonstrated that the test piece of Example had the desired fatigue resistance.

  FIG. 5 is an explanatory view showing a state of a durability test against repeated pressing under a high temperature environment. At the time of this durability test, the pressure source side plug HC and the mesh plug MC are attached to both ends of the hose as shown in the figure, and fastened by the fastening belt B. This belt fastening torque is about 6 Nm. The pressurizing source side plug HC is connected to the main pipe MH from the pressurizing pump P, and the pressurizing pump P pressurizes the pressurized fluid into the sample hose through the main valve MV. A fluid discharge pipe EH is branched from the main pipe MH, and the pressurized fluid is discharged by opening the discharge valve EV after closing the main valve MV. In this repeated durability test (pressurized repeated durability test), the heat-resistant hose 10 (sample hose) in which the above-mentioned pressure source side plug HC and the like have been set is placed in a high-temperature environment of 200 ° C., and 360 KPa is applied. The test was repeated for pressure / release (0 KPa) and the test for repeated pressurization / release (0 KPa) of 400 KPa. This pressurization / release was repeated at intervals of about 1.5 seconds. About the above-mentioned comparative example hose, it used for the test which repeats pressurization and release (0 KPa) of 260 KPa, and the test which repeats pressurization and release (0 KPa) of 300 KPa. FIG. 6 is a graph showing the test results of a repeated pressure durability test under a high temperature environment.

  As shown in FIG. 6, in the comparative hose, the hose broke after about 70,000 times in repeated pressurization at 300 KPa in a high temperature environment of 200 ° C., and under 1 million times in repeated pressurization at 260 KPa. Resistance to repetition (fatigue resistance to pressure repetition) was observed. On the other hand, in the heat-resistant hose 10 of the example, fatigue resistance to repeated pressurization of about 1 million times was observed in repeated pressurization at 360 KPa and 400 KPa. In this embodiment, it is assumed that the turbocharger of the automobile engine and the intake pipe are connected. Therefore, in the fatigue resistance evaluation for repeated pressurization, an increase of about 1 million times is performed at 300 KPa repeated pressurization. Since it is only necessary to have fatigue resistance against pressure repetition, it was demonstrated that the heat-resistant hose 10 of the example has the desired fatigue resistance.

  And it was proved that the heat-resistant hose 10 of the example has fatigue resistance that is about 10,000 times better than that of the comparative hose from the viewpoint of fatigue resistance against repeated stretching. Moreover, also from the viewpoint of fatigue resistance against repeated pressure, the heat-resistant hose 10 of the example is about 1.4 to 1.8 times superior in pressure when the fatigue resistance of 1 million times can be secured. It was proved to have fatigue resistance.

  Moreover, the expansion degree of the hose diameter of the heat-resistant hose 10 and the comparative example hose in which fatigue resistance of 1 million times was observed in the fatigue resistance test against repeated pressurization was measured. In the heat-resistant hose 10 of the example, only about 5% expansion was observed with respect to the diameter 53 mm before the test, but in the comparative hose, about% expansion was observed. This coincides with the fact that the heat resistant hose 10 of the example has excellent fatigue resistance as compared with the comparative hose as described above.

  The present invention is not limited to the above-described embodiments, and can be implemented in various modes without departing from the scope of the invention.

1 is a perspective view schematically showing each layer having a heat-resistant hose 10 according to an embodiment of the present invention broken away. It is explanatory drawing explaining the hose manufacturing apparatus 30. FIG. It is explanatory drawing which shows the mode of the durability test with respect to the expansion | extension repetition in a high temperature environment. It is a graph showing the test result of the extending | stretching repetition durability test in a high temperature environment. It is explanatory drawing which shows the mode of the durability test with respect to the pressurization repetition in a high temperature environment. It is a graph showing the test result of the pressure repetition durability test in a high temperature environment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Heat resistant hose 12 ... 1st inner surface rubber layer 12a ... Flow path 14 ... 2nd inner surface rubber layer 16 ... Reinforcement thread layer 16a ... Reinforcement thread 18 ... Outer surface rubber layer 20A ... Extrusion body 20a ... Space 30 ... Hose manufacturing apparatus 40 ... 1st extruder 50 ... Blade device 52 ... Drum 60 ... 2nd extruder 61 ... Outer tube extrusion part B ... Fastening belt EH ... Discharge piping EV ... Discharge valve HC ... Pressure source side plug HJ ... Holding jig MC ... Mekura Stopper MH ... Main piping MV ... Main valve Md ... Mandrel P ... Pressure pump

Claims (1)

A heat-resistant hose,
A first inner rubber layer that is formed using a fluorine compound-based rubber and is located on the innermost hose side of the hose to form the fluid flow path;
A second inner rubber layer laminated on the outer periphery of the first inner rubber layer and formed using silicon rubber;
A reinforcing yarn layer formed by winding a reinforcing yarn on the second inner rubber layer;
An outer rubber layer formed on the reinforcing yarn layer and formed using silicon rubber;
The silicon rubber of the second inner rubber layer and the outer rubber layer has an elongation in an environment of 180 ° C. of 120 to 250%,
The heat-resistant hose, wherein the reinforcing yarn layer is formed by winding the reinforcing yarn having a fineness of 2500 to 4000 dtex with a driving number of 64 to 76 strokes.

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