JP6107121B2 - Rubber hose - Google Patents

Description

  The present invention relates to a rubber hose in which a fiber reinforcing layer is embedded, and more particularly, to a rubber hose capable of improving kink resistance while suppressing an increase in hose weight.

  A hydraulic rubber hose that is connected to a hydraulic device or the like and distributes hydraulic oil generally has a reinforcing layer embedded therein to ensure pressure resistance. If the bending radius is too small when the rubber hose is bent, the inner peripheral side (bending compression side) of the hose is buckled, and so-called kinks occur.

  By the way, the reinforcing layer includes a steel reinforcing layer composed of a steel cord and a fiber reinforcing layer composed of various fibers. In the case of a rubber hose with an embedded steel reinforcement layer, the bending rigidity of the steel reinforcement layer is much higher than that of the rubber layer. Therefore, in order to improve the kink resistance and prevent the occurrence of kinks, The specification needs to be changed.

  On the other hand, in the case of a rubber hose in which the fiber reinforcement layer is embedded, the difference in bending rigidity between the fiber reinforcement layer and the rubber layer is not large compared to the rubber hose in which the steel reinforcement layer is embedded. It is also possible to improve the kink resistance by increasing the layer thickness. Of course, it is also possible to improve the kink resistance by changing the specification to increase the bending rigidity, such as increasing the number, density and outer diameter of the fiber reinforced layer.

  However, changing the specification of the fiber reinforced layer significantly increases the hose weight. Further, there is a problem that even if the outer rubber layer is simply thickened, the hose weight is significantly increased.

  Although the subject is different from the present invention, a rubber hose in which a steel cord is spirally embedded on the outer peripheral side of the pressure-resistant reinforcing layer has been proposed (see Patent Document 1). In the proposed rubber hose, it becomes easy to prevent the occurrence of kinks by the steel cord embedded in a spiral shape, but since the steel cord is embedded, it is impossible to avoid a significant increase in the weight of the hose.

JP 2008-281092 A

  An object of the present invention is to provide a rubber hose that can improve kink resistance while suppressing an increase in the weight of the hose.

In order to achieve the above object, the rubber hose of the present invention is a rubber hose in which a fiber reinforcing layer is embedded between an inner rubber layer and an outer rubber layer, and the hose longitudinal direction is spaced circumferentially on the surface of the outer rubber layer. a plurality of rubber surface protrusions are formed extending, the height of the surface protrusions is not less 3mm or more, and state, and are the 1mm or more the thickness of the surface protrusions is not present part of the outer rubber layer The width of the bottom surface of the surface protrusion is set to be shorter than the width of the upper surface, and both side surfaces in the width direction of the surface protrusion are inclined in the direction of increasing the width dimension from the bottom surface to the upper surface. And

  According to the rubber hose of the present invention, a plurality of rubber surface protrusions extending in the hose longitudinal direction at an interval in the circumferential direction are formed on the surface of the outer rubber layer, and the height of the surface protrusion is 3 mm or more. These surface protrusions function as reinforcing members against bending deformation. Therefore, the kink resistance of the hose can be improved without changing the specification of the fiber reinforcement layer. In addition, since the increase in the rubber volume is suppressed as compared with the case where the thickness of the outer rubber layer is simply increased, the increase in the hose weight can be suppressed.

  Further, since the thickness of the portion of the outer rubber layer where the surface protrusion is not present is 1 mm or more, the fiber reinforcing layer can be protected by the outer rubber layer. Since an outer rubber layer of 1 mm or more is secured, it is possible to firmly crimp the hose metal fitting into the outer rubber layer.

It is a cross-sectional view which illustrates the reference form of the rubber hose of this invention. It is a side view which illustrates the reference form in which the surface protrusion was formed in parallel with the hose longitudinal direction. It is a side view which illustrates the reference form in which the surface protrusion was formed helically. It is a cross-sectional view of the reference form showing a modification of the surface protrusion. It is a cross-sectional view of an embodiment showing a surface protrusion . It is a cross-sectional view of the reference form showing still another modification of the surface protrusion. It is a cross-sectional view which shows the test sample (reference example and comparative examples 1 and 2) of a rubber hose, and the position of the bending surface. It is a cross-sectional view which shows the test sample ( Reference Examples 1-1, 2-1, 3 and 4) of a rubber hose and the position of the bending surface. It is a cross-sectional view which shows the test sample ( Reference Examples 1-2 and 2-2) of a rubber hose, and the position of the bending surface. It is explanatory drawing which shows the outline | summary of a bending test.

  Hereinafter, the rubber hose of the present invention will be described based on the embodiments shown in the drawings.

  As illustrated in FIGS. 1 and 2, the rubber hose 1 of the present invention is configured by sequentially laminating a fiber reinforcing layer 3 and an outer rubber layer 4 coaxially on the outer side of the inner rubber layer 2. The rubber hose 1 is connected to a hydraulic device or the like that is fixed at a predetermined position. Therefore, the rubber hose 1 is installed in a stationary state at a substantially constant position. The inner diameter of the hose is not particularly limited, but is preferably about 50 mm to 100 mm, for example. Of course, the present invention can be applied to the case where the inner diameter of the hose is less than 50 mm and more than 100 mm.

  The inner peripheral side of the inner rubber layer 2 is a circular cross-sectional flow path through which fluid (hydraulic oil, water, air, etc.) flows, and the fluid flows through the rubber hose 1 at a relatively low pressure. The fluid pressure is, for example, about 2 MPa or less, or about 1 MPa or less.

  For the inner rubber layer 2, an appropriate rubber type is selected according to the fluid flowing. As the rubber of the inner rubber layer 2, styrene-butadiene copolymer rubber, butadiene rubber, butyl rubber, ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, chloroprene rubber, ethylene copolymer The rubber composition which has at least 1 sort (s) of rubber | gum as a main component among rubber | gum and an acrylonitrile butadiene type copolymer rubber can be illustrated.

  The fiber reinforcing layer 3 is formed of fibers that are generally used as reinforcing materials for hoses. Examples of the types of fibers include polyester fibers such as PET, polyamide fibers such as nylon 6 and 6, aramid fibers, vinylon fibers, rayon fibers, and polyparaphenylene benzbisoxazole (PBO) fibers.

  The structure of the fiber reinforcement layer 3 is not specifically limited, For example, it is a blade structure or a spiral structure. The number of fiber reinforcing layers 3 is not limited to one, and there may be a plurality of layers such as two layers and three layers. In the case of a plurality of fiber reinforced layers 3, interlayer rubber generally used is interposed between the layers.

  As the rubber of the outer rubber layer 4, the rubber composition exemplified above as the inner rubber layer 2 can be used. Different rubber compositions can be used for the outer rubber layer 4 and the inner rubber layer 2, or the same rubber composition can be used.

A plurality of rubber surface protrusions 5 are formed on the surface of the outer rubber layer 4 so as to extend in the hose longitudinal direction at intervals in the circumferential direction. In this reference embodiment , eight surface protrusions 5 are formed in parallel to the hose longitudinal direction. The rubber of the surface protrusion 5 and the rubber of the outer surface rubber layer 4 are the same rubber, and the surface protrusion 5 and the outer surface rubber layer 4 are a single body. That is, the surface protrusion 5 is formed by making the surface of the outer rubber layer 4 uneven. Therefore, a surface groove 6 is formed between the surface protrusions 5 adjacent to each other in the circumferential direction.

The number of the surface protrusions 5 is preferably three or more, for example, about 3 to 16, more preferably about 4 to 8. And it is preferable that each surface protrusion 5 is the same specification, and is arrange | positioned at equal intervals in the circumferential direction. In this reference form , the width B of the bottom surface of the surface protrusion 5 and the width B of the top surface are set to the same length. In addition, the bottom surface and the top surface of the surface protrusion 5 are set at the same position in the circumferential direction.

  The height t2 of the surface protrusion 5 is 3 mm or more. Further, the thickness t1 of the portion of the outer rubber layer 4 where the surface protrusion 5 is not present (hereinafter referred to as the base portion) is 1 mm or more. In other words, the rubber hose 1 is formed with a plurality of surface grooves 6 extending in the circumferential direction at intervals in the circumferential direction on the surface of the outer rubber layer 4, and the depth t2 of the surface groove 6 is 3 mm or more. It has become. The upper limit of the height t2 of the surface protrusion 5 is, for example, 50 mm. Therefore, the height t2 of the surface protrusion 5 is about 3 mm to 50 mm, more preferably about 3 mm to 30 mm. The width B of the surface protrusion 5 is, for example, about 5 mm to 50 mm, and more preferably about 10 mm to 40 mm. In the present invention, the width B of the surface protrusion 5 means an average value of the width of the bottom surface and the width of the upper surface of the surface protrusion 5.

  When the rubber hose 1 is bent, if the bending radius is too small, the hose inner peripheral side (bending compression side) buckles and a kink is generated. Therefore, these surface protrusions 5 function as reinforcing members against bending deformation. As a result, kinks are less likely to occur if the bend radii are the same, in other words, the bend radii where kinks occur are reduced, and the kink resistance is improved.

  Therefore, the kink resistance of the rubber hose 1 can be improved without changing the specification of the fiber reinforcement layer 3. Furthermore, an increase in the rubber volume can be suppressed as compared with a case where the thickness of the outer rubber layer 4 is simply increased uniformly over the entire circumference in the circumferential direction. Therefore, excellent kink resistance can be ensured while suppressing an increase in hose weight. Along with this, the rubber hose 1 can be connected to a hydraulic device or the like with a small bending radius, so that connection is possible even in a narrow space.

  In addition, if the height t2 of the surface protrusion 5 is less than 3 mm, the kink resistance cannot be sufficiently improved. On the other hand, when the height t2 of the surface protrusion 5 exceeds 50 mm, the effect of suppressing an increase in the hose weight is reduced. The same can be said about the width B of the surface protrusion 5 but the effect of the width B of the surface protrusion 5 on the kink resistance is high considering the section modulus of the rubber hose 1 (outer rubber layer 4). It becomes smaller than t2.

  In the rubber hose 1 of the present invention, since the thickness t1 of the base portion is 1 mm or more, the fiber reinforcing layer 3 can be protected by the outer rubber layer 4 (base portion rubber). Thereby, since damage to the fiber reinforcement layer 3 is prevented, the pressure resistance and bending rigidity by the fiber reinforcement layer 3 are not impaired.

  By the way, in order to connect the rubber hose 1 to equipment, a hose fitting is attached to the end portion in the longitudinal direction of the rubber hose 1. When the hose fitting is attached, the surface protrusion 5 at the longitudinal end portion of the rubber hose 1 is removed, and the end portion of the hose is processed into the thickness t1 of the base portion. Then, the hose fitting is crimped and attached to the processed hose end.

  Thus, in the rubber hose 1 of the present invention, the outer rubber layer 4 of 1 mm or more can be secured, so that the hose fitting can be bitten into the outer rubber layer 4 and crimped. This makes it possible to firmly fix the hose fitting to the hose end.

  When the thickness t1 of the base portion is less than 1 mm, it is difficult to protect the fiber reinforcement layer 3. Further, when crimping the hose fitting, it is difficult to firmly fix the hose fitting because the thickness t1 of the outer rubber layer 4 (base portion) is too thin. The upper limit of the thickness t1 of the base portion is, for example, about 30 mm. Therefore, the thickness t1 of the base portion is about 1 mm to 30 mm, more preferably about 1 mm to 15 mm.

  In addition, when the surface protrusion 5 is formed in parallel with the hose longitudinal direction, the kink resistance performance varies depending on the positional relationship between the surface protrusion 5 and the bending surface C as described later in the embodiment. Therefore, when the rubber hose 1 is bent and connected to a hydraulic device or the like, the position of the bending surface C may be set so as to exhibit the most excellent kink resistance.

  As illustrated in FIG. 3, the surface protrusion 5 may be formed in a spiral shape on the outer rubber layer 4 so as to extend in the longitudinal direction of the hose. That is, a plurality of surface grooves 6 arranged at intervals in the circumferential direction are formed so as to extend spirally in the hose longitudinal direction. In this specification, the bending rigidity of the rubber hose 1 is the same regardless of the position of the bending surface C. Therefore, the difference in kink resistance performance due to the circumferential position of the bending surface C can be eliminated.

The cross-sectional shape of the surface protrusion 5 is not limited to the shape illustrated in FIG. 1, and other cross-sectional shapes may be employed. For example, as illustrated in FIG. 4, as a reference form, the bottom surface width B and the top surface width B of the surface protrusion 5 are set to the same length, and the bottom surface and the top surface of the surface protrusion 5 are circumferential. It is also possible to make the specification set at a shifted position.

In the present invention, as illustrated in FIG. 5, the width b1 of the bottom surface of the surface protrusion 5 is set to be shorter than the width b2 of the upper surface, and both side surfaces in the width direction of the surface protrusion 5 are directed from the bottom surface to the upper surface. to specifications are inclined in a direction to increase the width. As illustrated in FIG. 6, as a reference form, the width b1 of the bottom surface of the surface protrusion 5 is set to be longer than the width b2 of the upper surface, and both side surfaces in the width direction of the surface protrusion 5 are directed from the bottom surface toward the upper surface. It can also be set as the specification which inclines in the direction which makes a width dimension small.

  When the rubber hose 1 (outer rubber layer 4) is molded by extrusion rather than by extrusion, the surface protrusion 5 having a cross-sectional shape illustrated in FIG. . The surface protrusion 5 having a cross-sectional shape illustrated in FIG. 1 is easy to manufacture although the draft taper is zero. The surface protrusion 5 having a cross-sectional shape illustrated in FIGS. 4 and 5 does not have a draft taper and has a so-called undercut shape. However, since the outer rubber layer 4 is elastically deformed, there is no problem in manufacturing.

  The surface protrusion 5 having a cross-sectional shape illustrated in FIG. 5 is advantageous in increasing the section modulus of the rubber hose 1 (outer rubber layer 4) because the rubber volume on the outermost peripheral side is larger. Therefore, it is most advantageous to increase the bending rigidity of the rubber hose 1.

  The rubber hose 1 of the present invention includes not only a rubber hose in which the inner rubber layer 2 and the outer rubber layer 4 are formed of rubber, but also a hose formed of a flexible elastomer similar to rubber.

An inner rubber layer (NBR rubber) having a predetermined layer thickness, two fiber reinforcing layers having a predetermined layer thickness (inner peripheral layer is a vinylon fiber blade structure, outer peripheral layer is an aramid fiber blade structure), outer rubber layer (SBR / NBR rubber), a hose inner diameter of 31.8 mm, and the outermost diameter of the fiber reinforced layer is 38.5 mm, and the rubber hose test sample S was prepared by changing only the layer thickness or shape of the outer rubber layer. (7 types in total: reference example, comparative examples 1 and 2, and reference examples 1 to 4). For each test sample S, the following kink occurrence length was measured, and the results are shown in Table 1.

  The reference example and comparative examples 1 and 2 have a normal shape in which the surface protrusion 5 is not provided on the surface of the outer rubber layer 4 as shown in FIG. In the reference example, the thickness T of the outer rubber layer 4 was 1 mm. The thickness T of the outer rubber layer 4 of Comparative Examples 1 and 2 was set to a value such that the rubber volume of the outer rubber layer 4 was as shown in Table 1. The rubber volume for the reference example in Table 1 is the rubber volume of the outer rubber layer 4 of each test sample S relative to the rubber volume of the outer rubber layer 4 of the reference example (reference 100). ing. A larger value means a larger rubber volume.

In Reference Examples 1 to 4, as shown in FIG. 8, four surface protrusions 5 having the same specifications are provided on the outer rubber layer 4 at regular intervals at intervals in the circumferential direction. The thickness t1 of the base portion of the outer rubber layer 4 is 1 mm. The height t2 of the surface protrusion 5 was 3.75 mm, and the width B of the surface protrusion 5 was set to a value such that the rubber volume of the outer rubber layer 4 was as shown in Table 1.

In Reference Examples 1 and 2, the surface protrusion 5 is formed in parallel to the hose longitudinal direction, and in Reference Examples 3 and 4, the surface protrusion 5 is formed in a spiral shape. In Reference Examples 1 and 2, the kink generation length varies depending on the positional relationship between the surface protrusion 5 and the bending surface C. Therefore, the bending surface C is positioned in two ways as shown in FIGS. The length was measured. In Table 1, the case of measuring in the state of FIG. 8 is shown in Reference Example 1-1, Reference Example 2-1, and the case of measuring in the state of FIG. 9 as Reference Example 1-2 and Reference Example 2-2.

[Length of kink]
For each test sample S, the test sample S is bent from the linear state shown in FIG. 10 (A) (distance between indexes L = 600 mm) with both ends in the longitudinal direction approaching each other as shown in FIG. 10 (B). I let you. Then, the index distance L1 when the kink K was generated was measured. The index distance L1 of the reference example is shown as an index with the reference being 100. The smaller the value, the better the kink resistance.

From the results of Table 1, it can be seen that if the rubber volume of the outer rubber layer is the same, the kink resistance performance of the reference example is improved compared to the comparative example. Reference Example 1-2 and Reference Example 3 have significantly improved kink resistance compared to Comparative Example 1, and Reference Example 2-2 and Reference Example 4 have improved kink resistance compared to Comparative Example 2. Reference Example 1-2 and Reference Example It can be seen that the improvement rate of 2-2 is remarkably high.

DESCRIPTION OF SYMBOLS 1 Rubber hose 2 Inner surface rubber layer 3 Fiber reinforcement layer 4 Outer surface rubber layer 5 Surface protrusion 6 Surface groove

Claims (3)

In a rubber hose in which a fiber reinforcement layer is embedded between an inner rubber layer and an outer rubber layer, a plurality of rubber surface protrusions extending in the hose longitudinal direction are formed on the surface of the outer rubber layer at intervals in the circumferential direction. , and the height of the surface protrusions is 3mm or more and the der thickness 1mm or more of the surface projection is not present part of the outer rubber layer is, the width of the bottom surface of the surface protrusion of the upper surface width A rubber hose characterized by being set to a shorter length and having both side surfaces in the width direction of the surface protrusions inclined in a direction of increasing the width dimension from the bottom surface to the top surface .   The rubber hose according to claim 1, wherein the surface protrusion is formed in a spiral shape.   The rubber hose according to claim 1, wherein the surface protrusion is formed in parallel to the longitudinal direction of the hose.

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