Patent Application
20190186656
This patent application claims priority to Chinese Patent Application No. 201711337970.0 filed Dec. 14, 2017, the disclosure of which is incorporated herein in its entirety, by reference.
The field to which the disclosure generally relates is flexible rubber hoses for low, medium, or, particularly, high pressure hydraulic applications.
This section provides background information to facilitate a better understanding of the various aspects of the disclosure. It should be understood that the statements in this section of this document are to be read in this light, and not as admissions of prior art.
Flexible rubber hose is used in a variety of hydraulic and other fluid transfer applications for conveying fluid pressures which for “high” pressure applications typically range from about 4000 psi (28 MPa) to 8000 psi (55 MPa) or more. In basic construction, hoses of the type herein involved typically are formed as having a tubular, inner tube or core surrounded by one or more outer layers of a braided or spiral-wound reinforcement material which may be a metal or metal-alloy wire or a natural or synthetic fiber. The reinforcement layers, in turn, are protected by a surrounding outermost jacket or cover which may be of the same or different material as the inner tube. The cover also provides the hose with increased abrasion resistance.
In the case of “rubber,” as opposed to thermoplastic, hose constructions, the inner tube, may be provided as formed of a vulcanizable natural or, more typically, a synthetic rubber material such as Buna-N or neoprene. Such material or blend may be conventionally extruded and cooled or cured to form the inner tube. In some cases, the tube may be cross-head extruded over a mandrel for support, or otherwise supported in later forming operations using air pressure and/or reduced processing temperatures.
From the extruder, the inner tube may be delivered through a braider and/or a spiral winder for its reinforcement with one or more surrounding layers of a wire and/or fibrous material or blend such as a monofilament, yarn, cord, yarn-wire composite, or roving. Such reinforcement layers are often applied under tension and typically may be formed of an interwoven braid or a spiral winding of a nylon, polyester, polyphenylene bezobisoxazole, polyvinyl acetate, or aramid yarn, or a high tensile steel or other metal wire. A relatively thin bonding or other interlayer of a vulcanizable rubber may be extruded or otherwise applied between each of the reinforcement layers to bond each layer to the next layer.
Following the braiding, winding, or other application of the reinforcement layers and the interlayers, an outer cover or sheath optionally may be applied. Such cover, which may be formed as a cross-head extrusion, a moisture-cured or solvent-based dipped coating, or a spiral-wound wrapping, typically comprises an abrasion-resistant synthetic rubber or a thermoplastic such as a polyurethane. Following the application of the cover, the hose construction so-formed by be heated to vulcanize the rubber layers and thereby consolidate the construction into an integral hose structure.
In normal use, such as in mobile or industrial hydraulic applications, hoses of the type herein involved may be exposed to a variety of environmental factors and mechanical stresses which cannot always be predicted. Of utmost importance to the integrity and performance of the hose is that a strong bond is achieved between the constituent parts thereof. However, while it is important to bond these parts together, it is also important that the hose not be made overly stiff so as to make it prone to kinking or fatigue or otherwise useable for certain applications.
Current spiral hose designs use multiple layers of materials. The hose typically starts with a rubber inner tube, and a layer of textile braid or leno fabric covers the tube which prevents ends of wire from penetrating the tube during the spiral process. A rubber tie gum covers the textile braid or leno fabric to develop adhesion between the tube and the first layer of wire, and multiple layers of wire are spirally wound around the hose, with rubber friction layers applied between each layer of wire. The wire layers are applied in alternating spiral directions. In other words, the first layer of wire reinforcement layer is applied in one spiral direction, then the next layer is applied in the opposing spiral direction, the next again in the same spiral direction as the first layer, and so on. The layers are applied is sets of two each and usually separated by a layer of rubber.
Finally the hose is covered by an outer layer of weather and abrasion resistant rubber. Hence, a conventional inner tube compound requires a textile braid or leno fabric to protect the soft uncured tube during the wire spiraling process. The textile braid or leno fabric prevents an end of wire from penetrating into the green tube during the spiral wire process. This protective layer is an expensive added cost and process to manufacture such hoses.
A problem with this design and method of manufacture is such hoses are too rigid and large in size. The industry seeks hydraulic hoses that are more flexible, more compact, have a smaller bend radius so the hose can be put into more compact environment, and reduced costs by using shorter lengths. Such needs are met, at least in part, by embodiments according to this disclosure.
This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
In a first aspect of the disclosure, hose embodiments include an inner tube defining a central longitudinal axis there through, and which is formed of vulcanized rubber, where the inner tube has a tube wall thickness (t) of between about 0.5 mm to about 1.5 mm. A first reinforcement layer is applied adjacent the inner tube in a spiral direction (+) at pitch angle θ, and a second reinforcement layer is applied in the same spiral direction (+), at pitch angle θ′. A third reinforcement layer is applied adjacent the second reinforcement layer, and the third reinforcement layer is applied in an opposing spiral direction (−) at pitch angle −θ. A cover disposed outward from the third reinforcement layer. In some aspects, the hose has a wall thickness (T), and the tube wall thickness (t) comprises less than about 25% of the hose wall thickness.
The vulcanized rubber may be an acrylonitrile butadiene rubber (NBR), a hydrogenated NBR (HNBR), a cross-linked NBR (XNBR), or copolymers and blends thereof. The inner tube may include a plurality of rod shaped particles orientated substantially parallel with the central longitudinal axis of the hose, and the plurality of rod shaped particles may be incorporated in an amount of 10% or less by weight, based upon total weight of the inner tube. In some cases, the plurality of rod shaped particles is incorporated in an amount of from 1% to 7% by weight, based upon total weight of the inner tube.
In some embodiments, a tie layer is disposed between the first reinforcement layer and the second reinforcement layer, and/or disposed between the second reinforcement layer and the third reinforcement layer.
In some embodiments a fourth reinforcement layer is applied adjacent third reinforcement layer, where the fourth reinforcement layer is applied in an opposing spiral direction (−), at pitch angle −θ′, or applied in a like spiral direction (+), at pitch angle θ″.
In another aspect of the disclosure, a hose includes an inner tube, a cover, and at least three reinforcement layers applied between the inner tube and the cover, where two immediately adjacent reinforcement layers of the at least three reinforcement layers are applied in same spiral directions (+) (+), and where another reinforcement layer of the at least three reinforcement layers is applied in an opposing spiral direction (−). The inner tube may have a tube wall thickness (t) of between about 0.5 mm to about 1.5 mm, and the hose may have a wall thickness (T), where the tube wall thickness (t) may be less than about 25% of the hose wall thickness. Optional tie layers may be disposed between the at least three reinforcement layers.
In some cases, the inner tube includes a plurality of rod shaped particles orientated substantially parallel with the central longitudinal axis of the hose. The plurality of rod shaped particles may be incorporated in an amount of 10% or less by weight, based upon total weight of the inner tube.
In yet another aspect of the disclosure, hose embodiments include an inner tube defining a central longitudinal axis there through, and formed from a vulcanized rubber. A first reinforcement layer is applied adjacent inner tube in a spiral direction (+) at pitch angle θ, a second reinforcement layer is applied in the same spiral direction (+) at pitch angle θ′, and a third reinforcement layer is applied in the same spiral direction (+) at pitch angle θ″. A fourth reinforcement layer is applied in an opposing spiral direction (−) at pitch angle −θ, and a fifth reinforcement layer is applied in the spiral direction (−) at pitch angle −θ′. A cover is disposed outward from the fifth reinforcement layer.
In some aspects, optional tie layers are disposed between the first reinforcement layer and the second reinforcement layer, between the second reinforcement layer and the third reinforcement layer, between the third reinforcement layer and the fourth reinforcement layer, and/or between the fourth reinforcement layer and the fifth reinforcement layer.
In some cases, the inner tube has a tube wall thickness (t) of between about 0.5 mm to about 1.5 mm. The hose may have a wall thickness (T), and the tube wall thickness (t) comprises less than about 25% of the hose wall thickness. Also, the inner tube may include a plurality of rod shaped particles orientated substantially parallel with the central longitudinal axis, and the plurality of rod shaped particles may be incorporated in an amount of 10% or less by weight, based upon total weight of the inner tube.
In some aspects, the fourth reinforcement layer and the fifth reinforcement layer have a combined tensile strength value which substantially equal to a combined tensile strength of the first reinforcement layer, the second reinforcement layer and the third reinforcement layer.
Certain embodiments of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood, however, that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein, and:
The following description of the variations is merely illustrative in nature and is in no way intended to limit the scope of the disclosure, its application, or uses. The description and examples are presented herein solely for the purpose of illustrating the various embodiments of the disclosure and should not be construed as a limitation to the scope and applicability of the disclosure. In the summary of the disclosure and this detailed description, each numerical value should be read once as modified by the term “about” (unless already expressly so modified), and then read again as not so modified unless otherwise indicated in context. Also, in the summary of the disclosure and this detailed description, it should be understood that a concentration or amount or value range listed or described as being useful, suitable, or the like, is intended that any and every concentration or amount or value within the range, including the end points, is to be considered as having been stated. For example, “a range of from 1 to 10” is to be read as indicating each and every possible number along the continuum between about 1 and about 10. Thus, even if specific data points within the range, or even no data points within the range, are explicitly identified or refer to only a few specific, it is to be understood that inventors appreciate and understand that any and all data points within the range are to be considered to have been specified, and that inventors had possession of the entire range and all points within the range.
Unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by anyone of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).
In addition, use of the “a” or “an” are employed to describe elements and components of the embodiments herein. This is done merely for convenience and to give a general sense of concepts according to the disclosure. This description should be read to include one or at least one and the singular also includes the plural unless otherwise stated.
The terminology and phraseology used herein is for descriptive purposes and should not be construed as limiting in scope. Language such as “including,” “comprising,” “having,” “containing,” or “involving,” and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited.
Also, as used herein any references to “one embodiment” or “an embodiment” means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily referring to the same embodiment.
For illustration purposes, the precepts of the compact rubber hose construction herein involved are described in connection with a configuration as particularly adapted for use in high pressure, i.e., between about 4000-8000 psi (28-55 MPa) mobile or industrial hydraulic applications. It will be appreciated, however, that aspects of the present disclosure may find use in other hose constructions for a variety or general hydraulic or other fluid transfer applications. Use within those such other applications therefore should be considered to be expressly within the scope of this disclosure.
Referring now to the figures wherein corresponding reference characters are used to designate corresponding elements throughout the several views with equivalent elements being referenced with prime or sequential alphanumeric designations, a representative conventional, prior art, hose construction is shown generally at 100 in the cut-away view of
As may be seen in the different views of
In an aspect of the disclosure, carbon rod shaped particles are mixed with the inner tube compound so as to effectively increase green strength and allow spiral wire processing without the use of a protective layer of textile braid or leno fabric. When the inner tube compound is extruded into the shape of the tube, the rod shaped particles at least substantially align longitudinally along the length (i.e. central longitudinal axis) of the tube. This produces very high tensile and modulus properties in the extruded direction, which is along the central longitudinal axis. These properties reduce tube deformation under high pressure impulse cycles which prevents pinholes in the tube and extends the life of the hose. The high longitudinal strength also better holds the fitting onto the end of the hose for longer assembly life.
Referring again to
With respect to the spiral-wound construction shown in
In the illustrated spiral wound construction of
As successively wound in the hose 100, the layers 130a-d each may have a predetermined pitched angle, referenced at −θ in
The outermost reinforcement layer 130d may be sheathed within one or more layers of a coaxially-surrounding protective cover or jacket, referenced at 140, having a circumferential interior surface, 142, and an opposing circumferential exterior surface, 144, which defines the hose outer diameter Do. Depending upon its construction, cover 140 may be spray-applied, dip coated, cross-head or co-extruded, or otherwise conventionally extruded, spiral or longitudinally, i.e., “cigarette,” wrapped, or braided over the reinforcement layer 130d,
Each of the reinforcement layers 130a-d within hose 100 may be bonded, such as chemically and/or mechanically, to its immediately succeeding layer 130 so as to provide for the more efficient transfer of induced internal or external stresses. Such bonding may be effected via the provision of a bonding agent in the form of an intermediate adhesive, resin, or other interlayer, 150a-c. In an illustrative embodiment, such bonding agent may be provided as an adhesive in the form of a melt-processible or vulcanizable material which is extruded or otherwise applied in a molten, softened, uncured or partially uncured, or otherwise flowable phase over each of the reinforcement layers 130a-d to form the respective interlayers 150a-c. Each such interlayer 150 may have a thickness of between about 1-25 mils (0.025-0.64 mm). The corresponding reinforcement layer 130 then may be wound over the corresponding interlayer 150 while it is still in its softened phase. Alternatively in the case of a thermoplastic interlayer 150, the layer may be reheated to effect its re-softening prior to the winding of reinforcement layer 130.
The material forming interlayers 150 specifically may be selected for high or low temperature performance, flexibility, or otherwise for compatibility with the reinforcement layers 130 and/or the inner tube 104 and cover 140. Suitable materials include natural and synthetic rubbers, as well as thermoplastic, i.e., melt-processible, or thermosetting, i.e., vulcanizable, resins which should be understood to also include, broadly, materials which may be classified as elastomers or hot-melts. Representative of such resins include plasticized or unplasticized polyamides such as nylon 6, 66, 11 and 12, polyesters, copolyesters, ethylene vinyl acetates, ethylene terpolymers, polybutylene or polyethylene terephthalates, polyvinyl chlorides, polyolefins, fluoropolymers, thermoplastic elastomers, engineering thermoplastic vulcanizates, thermoplastic hot-melts, copolymer rubbers, blends such as ethylene or propylene-EPDM, EPR, or NBR, polyurethanes, and silicones. In the case of thermoplastic resins, such resins typically will exhibit softening or melting points, i.e., Vicat temperatures, of between about 77-250° C. For amorphous or other thermoplastic resins not having a clearly defined melting peak, the term melting point also is used interchangeably with glass transition point.
With each of the respective layers 104, optional tie layer 110, 130a, 150a, 130b, 150b, 130c, 150c, 130d, and 140 being extruded, wound, or otherwise formed sequentially in such order, following the application of the cover 140, the hose 100 may be heated to vulcanize the rubber layers and thereby consolidate the construction into an integral hose structure.
All of the aspects, characteristics, dimensions and materials described above for conventional prior art hydraulic hoses may be useful, or otherwise applied to the inventive hoses according to the disclosure. However, in contrast to the conventional prior art hydraulic hoses, hydraulic hoses according to the disclosure have at least two adjacent reinforcement layers applied in the same spiral direction, and at least another reinforcement layer applied in an opposing spiral direction. Thus, in a hose having three reinforcement layers, two adjacent layers are applied in a like spiral direction, while the third is applied in the opposing spiral direction. This concept is depicted in
With reference to
Now referencing
With reference to
Now referencing
With reference to
The hose embodiments shown in
Inner tubes used in hose embodiments according to the disclosure may be provided as extruded or otherwise formed of a vulcanizable, chemically-resistant, synthetic rubber. As used herein, “chemical resistance” should be understood to mean the ability to resist swelling, crazing, stress cracking, corrosion, or otherwise to withstand attack from organic solvents and hydrocarbons, such as hydraulic fluids. Suitable materials include acrylonitrile butadiene rubbers (NBR) and modified NBR's such as hydrogenated NBR (HNBR) and cross-linked NBR (XNBR), as well as copolymers and blends, thereof. Such blends may be, for example, XNBR or HNBR blended with one or more of a chlorinated polyethylene (CPE), polyvinyl chloride (PVC), or polychloroprene (CR).
In its raw, i.e., uncompounded, form, the NBR may have a mid to high acrylonitrile (ACN) content of between about 19-36%, and a Mooney viscosity ((ML 1+4)@212° F. (100° C.)) of at least about 90. Such viscosity allows the rubber material to be compounded with between about 15-66% by total weight of the compound of one or more reinforcing fillers. Each of such fillers may be provided, independently, as a powder or as flakes, fibers, or other particulate form, or as a mixture of such forms. Typical of such reinforcing fillers include carbon blacks, clays, and pulp fibers. For powders, the mean average particle size of the filler, which may be a diameter, imputed diameter, screen, mesh, length, or other dimension of the particulate, may range between about 10-500 nm.
Additional fillers and additives may be included in the formulation of the rubber compound depending upon the requirements of the particular application envisioned. Such fillers and additives, which may be functional or inert, may include curing agents or systems, wetting agents or surfactants, plasticizers, processing oils, pigments, dispersants, dyes, and other colorants, opacifying agents, foaming or anti-foaming agents, anti-static agents, coupling agents such as titanates, chain extending oils, tackifiers, flow modifiers, pigments, lubricants, silanes, and other agents, stabilizers, emulsifiers, antioxidants, thickeners, and/or flame retardants. The formulation of the material may be compounded in a conventional mixing apparatus as an admixture of the rubber and filler components, and any additional fillers or additives. As vulcanized and filled with between about 15-66% of a carbon black filler.
The tension and area coverage at which the reinforcement layers are braided, wound, or knitted may be varied to achieve the desired flexibility, which may be measured by bend radius, flexural forces, or the like, of the hose embodiments.
In the illustrated constructions which may be particularly adapted for high pressure hydraulic applications, each of the reinforcement layers may be spiral wound from one end of a monofilament carbon or stainless steel wire having a generally circular cross-section with a diameter of between about 0.008-0.04 inch (0.2-1 mm). As so formed, each of the reinforcement layers thus may have a thickness of that of the wire diameter. Although a circular wire is shown, a “flat-wire” construction alternatively may be employed using wires having a rectangular, square, or other polygonal cross-section. Low profile oval or elliptical wires also may be used. To better control the elongation and contraction of the hose embodiments, and for improved impulse fatigue life, the innermost reinforcement layer may be bonded, by means of fusion, i.e., vulcanization of the inner tube, mechanical, chemical, or adhesive bonding, or a combination thereof or otherwise, to the outer surface of the inner tube. In some aspects, such bonding is achieved with a tie layer disposed between the innermost reinforcement layer and outer surface of the inner tube.
In those embodiments where tie layer is disposed between the innermost reinforcement layer and outer surface of the inner tube, the tie layer may be formed of one or more bonding resins which is to be provided between the reinforcement layer and outer surface to effect a bond across the entirety of these layers. Representative examples of such resins include Ricobond® 1756 for peroxide cured compounds and Ricobond® 1731 for sulfur cured compounds.
In some aspects, the coaxially-surrounding protective cover or jacket used in hose embodiments according to the disclosure, may be a thick layer of a fiber, glass, ceramic, or metal-filled, or unfilled, abrasion-resistant thermoplastic, i.e., melt-processible, or thermosetting, vulcanizable natural rubber or a synthetic rubber such as fluoropolymer, chlorosulfonate, polybutadiene, butyl, neoprene, nitrile, polyisoprene, and buna-N, copolymer rubbers such as ethylene-propylene (EPR), ethylene-propylene-diene monomer (EPDM), nitrile-butadiene (NBR) and styrene-butadiene (SBR), or blends such as ethylene or propylene-EPDM, EPR, or NBR, and copolymers and blends of any of the foregoing. The term “synthetic rubbers” also should be understood to encompass materials which alternatively may be classified broadly as thermoplastic or thermosetting elastomers such as polyurethanes, silicones, fluorosilicones, styrene-isoprene-styrene (SIS), and styrene-butadiene-styrene (SBS), as well as other polymers which exhibit rubber-like properties such as plasticized nylons, polyesters, ethylene vinyl acetates, and polyvinyl chlorides. As used herein, the term “elastomeric” is ascribed its conventional meaning of exhibiting rubber-like properties of compliancy, resiliency or compression deflection, low compression set, flexibility, and an ability to recover after deformation, i.e., stress relaxation. By “abrasion-resistant,” it is meant that such material for forming the cover may have a hardness of between about 60-98 Shore A durometer.
Any of the materials forming the cover layers in hose embodiments according to the disclosure may be loaded with metal particles, carbon black, or another electrically-conductive particulate, flake, or fiber filler so as to render the hoses electrically-conductive for static dissipation or other applications. Separate electrically-conductive fiber or resin layers (not shown), which may be in the form of spiral or “cigarette-wrapped” tapes or otherwise provided, also may be included in the hose constructions between the inner tube and the innermost reinforcement layer, between the reinforcement layers, or between the outermost reinforcement layer and cover.
Similar to the bonding of an inner tube to the innermost reinforcement layer, or to a textile or other layer there between, the interior surface of a cover layer may be bonded to the outermost reinforcement layer. Such bond, again, may be by fusion, chemical, mechanical, or adhesive means, or a combination thereof or other means.
Thus, illustrative rubber hose constructions are described which are of compact designs, and which are very flexible. Such constructions may be rated, such as under SAE J517 or J1754, ISO 3862 or J1745, and/or DIN EN 856, or otherwise adapted for use in a variety applications such as mobile or industrial hydraulic installations specifying relatively high working pressures of between about 4000-8000 psi (28-55 MPa), or otherwise for a variety of pneumatic, vacuum, shop air, general industrial, maintenance, and automotive applications such as for air, oil, antifreeze, and fuel. These designs could also be used in high pressure oil drilling applications such as chock and kill hose or rotary drilling hose. They also could be used in high pressure compact braided hydraulic hose.
The foregoing description of the embodiments has been provided for purposes of illustration and description. Example embodiments are provided so that this disclosure will be sufficiently thorough, and will convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the disclosure, but are not intended to be exhaustive or to limit the disclosure. It will be appreciated that it is within the scope of the disclosure that individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
Although a few embodiments of the disclosure have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201711337970.0 | Dec 2017 | CN | national |
