CA1057676A - Hydraulic hose - Google Patents
Hydraulic hoseInfo
- Publication number
- CA1057676A CA1057676A CA253,787A CA253787A CA1057676A CA 1057676 A CA1057676 A CA 1057676A CA 253787 A CA253787 A CA 253787A CA 1057676 A CA1057676 A CA 1057676A
- Authority
- CA
- Canada
- Prior art keywords
- layer
- strands
- core tube
- layers
- hydraulic hose
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L11/00—Hoses, i.e. flexible pipes
- F16L11/04—Hoses, i.e. flexible pipes made of rubber or flexible plastics
- F16L11/08—Hoses, i.e. flexible pipes made of rubber or flexible plastics with reinforcements embedded in the wall
- F16L11/081—Hoses, i.e. flexible pipes made of rubber or flexible plastics with reinforcements embedded in the wall comprising one or more layers of a helically wound cord or wire
- F16L11/082—Hoses, i.e. flexible pipes made of rubber or flexible plastics with reinforcements embedded in the wall comprising one or more layers of a helically wound cord or wire two layers
Abstract
HYDRAULIC HOSE
Abstract of the Disclosure A hydraulic hose having improved burst strength at high temperatures has an extruded synthetic polymer core tube and at least two layers of helically wound fibrous strands which are mechanically bonded together with an extruded polymer.
Abstract of the Disclosure A hydraulic hose having improved burst strength at high temperatures has an extruded synthetic polymer core tube and at least two layers of helically wound fibrous strands which are mechanically bonded together with an extruded polymer.
Description
~,i`
This invention relates generally to hydraulic hose and more particularly to an improved hose constructed of synthetic materials.
It has been proposed before to provide a hydraulic hose having an extruded synthetic polymeric core tube, fibrous material disposed about the core tube to reinforce it against bursting under the pressure of fluids conveyed by the hose and an extruded polymeric sheath to protect the fibrous ma-terial from abrasion. For example, such hoses are disclosed in the Matthews Paten~ U.S. 3,604,461 and in the Atwell Patent i U~S. 3,654,967. The fibrous reinforcing material may be braided synthetic filaments or, as disclosed by Matthews and Atwell, the ibrous reinforcing material may be layers of synthetic filaments helically wound about ~he core tube. The helically wound reinforcement is always used in pairs of overlapping ~`
` oppositely wound layers to resist both radial and axial elon-gation of the hose under pressure. The helically wound rein-forcement~ or so-called "lapped construction" has the advantage ;~
over braided layers that it can be applied at faster production rates and, because there is no interweaving of fibers as in braiding, it permits greater efficiency in the use of the fiber .. , :.
and increased fatigue life. ~owever, in order to obtain optimum performance, each layer, i.e., each layer of helically wound fibers must be bonded to the adjacent layer.
Both ~atthews and Atwell recognize that the adjacent layers must be bonded together. Matthews bonds the layers together by flowing a heated bonding agent such as Adiprene L-100, a polyurethane prepolymer, over the surface layer of .,: :, -.' ;., :~ ,:
',. ' - 1 - ~ ' ':
,: ' ;: .
,~ ~
~ ~S7Ç~
reinforcing material wound about a core tube, passes the coated product through a wiper to spread the bonding agent over the surface and then winds a second layer of filaments over the bonding material.
Atwell, on the other hand, bonds the adjacent layers - -together by applying a solvent such as resorcinol to the surface of one layer and winding a second layer over the `
`~ solvent-wet surface. The assembly must then be passed through ; ~ ;
a hot water bath to remove the solvent.
If the bond is made by an adhesive or bonding mechanism ;~
~;i which is weak or flexible the burst strength of the hose is `~
j , . .
~`~ low. But if the bond is strong or very stiff, the hose burst strength is much higher. With no bond at all the burst is very low showing very poor efficiency in fiber use. In fact, with-out any bonding on a hose with a single lap (2 layers) of ~r~ helically wound reinforcement, the burst strength is not as ~:: ! good as it would be if braided reinforcing material were used. `~
~i The method of bonding usediby Atwell is to dissolve a `~
; portion of the fibers in each layer and bond these dissolved fibers to each other. This has the disadvantage that it is `;
necessary to replace that portion of the fiber lost by dis- ;
solution to compensate for loss in burst strength. ~ ! .
The Matthews type of bond has the advantage over the Atwell bond that no fibers are destroyed and also the bond is resilient and elastomeric. With the Atwell bo~d, the fibers themselves carry the load and do not have the resilience to withstand overload without breaking which weakens the bond ~, interface and deleteriously afects the hose performance. i k s ~
This invention relates generally to hydraulic hose and more particularly to an improved hose constructed of synthetic materials.
It has been proposed before to provide a hydraulic hose having an extruded synthetic polymeric core tube, fibrous material disposed about the core tube to reinforce it against bursting under the pressure of fluids conveyed by the hose and an extruded polymeric sheath to protect the fibrous ma-terial from abrasion. For example, such hoses are disclosed in the Matthews Paten~ U.S. 3,604,461 and in the Atwell Patent i U~S. 3,654,967. The fibrous reinforcing material may be braided synthetic filaments or, as disclosed by Matthews and Atwell, the ibrous reinforcing material may be layers of synthetic filaments helically wound about ~he core tube. The helically wound reinforcement is always used in pairs of overlapping ~`
` oppositely wound layers to resist both radial and axial elon-gation of the hose under pressure. The helically wound rein-forcement~ or so-called "lapped construction" has the advantage ;~
over braided layers that it can be applied at faster production rates and, because there is no interweaving of fibers as in braiding, it permits greater efficiency in the use of the fiber .. , :.
and increased fatigue life. ~owever, in order to obtain optimum performance, each layer, i.e., each layer of helically wound fibers must be bonded to the adjacent layer.
Both ~atthews and Atwell recognize that the adjacent layers must be bonded together. Matthews bonds the layers together by flowing a heated bonding agent such as Adiprene L-100, a polyurethane prepolymer, over the surface layer of .,: :, -.' ;., :~ ,:
',. ' - 1 - ~ ' ':
,: ' ;: .
,~ ~
~ ~S7Ç~
reinforcing material wound about a core tube, passes the coated product through a wiper to spread the bonding agent over the surface and then winds a second layer of filaments over the bonding material.
Atwell, on the other hand, bonds the adjacent layers - -together by applying a solvent such as resorcinol to the surface of one layer and winding a second layer over the `
`~ solvent-wet surface. The assembly must then be passed through ; ~ ;
a hot water bath to remove the solvent.
If the bond is made by an adhesive or bonding mechanism ;~
~;i which is weak or flexible the burst strength of the hose is `~
j , . .
~`~ low. But if the bond is strong or very stiff, the hose burst strength is much higher. With no bond at all the burst is very low showing very poor efficiency in fiber use. In fact, with-out any bonding on a hose with a single lap (2 layers) of ~r~ helically wound reinforcement, the burst strength is not as ~:: ! good as it would be if braided reinforcing material were used. `~
~i The method of bonding usediby Atwell is to dissolve a `~
; portion of the fibers in each layer and bond these dissolved fibers to each other. This has the disadvantage that it is `;
necessary to replace that portion of the fiber lost by dis- ;
solution to compensate for loss in burst strength. ~ ! .
The Matthews type of bond has the advantage over the Atwell bond that no fibers are destroyed and also the bond is resilient and elastomeric. With the Atwell bo~d, the fibers themselves carry the load and do not have the resilience to withstand overload without breaking which weakens the bond ~, interface and deleteriously afects the hose performance. i k s ~
2 ~r ,,"'''1,', 1 ' ~
~ i ,5~7~'76 With the resilient bond mechanism of Matthews, the bonding materials tend to soak in and saturate the fiber layers and eliminate the desired mobility of fibers in the reinforcing layer. The Matthews construction inherently gives a very stiff hose. Any attempts to increase flexibility by making the adhesive more flexible also weakens the bond ; and lowers hose performance. Therefore, the Matthews hose can be stiff with high performance or flexible with low performance, but never both.
It has also been proposed to coat layers of braided insulation with a rubber solution such as, for example in :;. j .
U.S. Patent No. 3,750,712. ~oreover, hoses having helically ~;`, wound layers of wire with a rubber intermediate ply have -1 been disclosed in U.S. Patents No's. 3,506,040; 2,033,559;
.....
l 3,481,368; 3,866,633; 2,237,490 and 2,047,770. In addition, i a hose having wound tape reinforcing is disclosed in U.S. `
Patent No. 1,940,868. Also, a pipe having at least three oppositely wound layers of reinforcing threads bonded by I wetting the threads with a bonding substance or by applying a liquid bonding material to surface of the wound threads is disclosed in U.S. Patent 3,107,698. However, none of the heretofore available hoses have a reinforcing structure ~ :;, 'I
for the core tube which is both flexible and sufficiently strong to provide a high burst strength. ;~
It is an object of this inven$ion to prc)vide a hose i ~ having a synthetic polymeric core tube and reinforcement for r; the core tube which is flexible and effectively supports the ~ core tube against bursting under high fluid pressures.
f~
~,, 5''''4 ' ,' : '~
! , . .' 1~5"~
Another object of the invention is to provide a hose having a synthetic polymeric core tube and oppositely helically ;
, ,. . ~ .
wound reinforcing strands of fibers with an improved bond ~
.. ~ .
between layers of the strands. A further object of the . . ~
invention i5 to provide a hose having oppositely helically wound layers of s~rands of synthetic fiber bonded together with a bonding material which does not modify or destroy the surface of the strands and provides a flexible and strong reinforcing structure for the core tuba.
Other objects will become apparent from the follow-ing description with reference to the accompanying drawing wherein .: ;;
; Figure 1 is a fragmentary side elevation illustrating ~
;. ~ , an embodiment of the invention;
. .~ .
....
;i Figure 2 is a cross-section taken along the line 2-2 i~ of Figure l; and ,, ~
`1 Figure 3 is a diagrammatic illustration of a method of ma!king the hose provided by the invention.
The foregoing objects and others are accomplished -~ 20 in accordance with this invention, generally speaking, by ;: :;
providing a hydraulic hose having an extruded synthetic ;
; polymeric core tube, a first layer or half-lap of helically ;
wound strands of fibroùs material wound in one direction di-rectly against the core tube and mechanically bonded thereto, a second layer of oppositely helically wound strands about the first layer, an extruded layer of flexible elastomeric material ` I disposed between the two layers mechanically bonding the layers together and preferably an extruded synthetic polymeric sheath , ., .
4 ;
,:, :
,. :, :
.
t~
., ~;
about the r~inforcing layers. The hose may have one, two or more pairs of half-laps of helicallY wound strands of fibrous material bonded together with an intermediate polymeric layer.
.: The novel hydraulic hose may be made by extruding :~ a synthetic polymer to form a core tube of indeterminate , ~ ~
; length, softening the surface of the core tube with a solvent , therefor, helically winding a layer of strands of fibrous ~.
~:~ material to form a layer on the core tube while the surface ~: :
.... .
; 10 is still soft at a tension whereby the skrands becomes only ; -partially embedded in the surface, extrud.ing a synthetic . .:
~ polymer over the first layer to form a flexible layer of f~ polymer and winding in a direction opposite from that of the j. fi.rst layer a second layer of strands of fibrous material , over the polymer layer while it is still soft at a.tension ~ ~ whereby the strands becomes only partially embedded therein i~ J to form a mechanical bond between the two layers. Additional . bonded layers may be provided and a sheath may be formed over ;;~
~¦ the surface of reinforcing layers by extruding a polymer ..
. 20 thereover. .:
:1 It has been found that the extruded layer of polymer ~: between the two layers forms a bond at the fiber layer .lnter-.,,, ;
. face with a minimum number of fibers of the strands being restrained so that the fibrous reinforcing material is re-silient and does not appreciably stiffen the tube. At the ~: same time, however, the lapped helically wound reinforcing material provides greater resistance to bursting of the core :~
tube than would a braid containing a similar number of fibers. `~
~ 5 ~ ~
~5~ 7~
~.
Since the extruded layer of polymer is a continuous coherent ~-~
layer of material the mechanical bonding of the two layers `
together does not aepend upon adhesion of the elastomeric layer to the fibers.
The core tube may be extruded from any suitable synthetic polymer such as, for example, an elastomeric poly~
urethane, nylon, a segmented thermoplastic copolyester . ~, , , ~: elastomer, polyvinyl chloride or the like. The segmented ~
.. . .
thermoplastic copolyester elastomer may be the one disclosed in U.S. Patent 3,766,146 or "Hytrel" sold by E.I. duPont de Nemours and Company. Suitable polyurethanes are disclosed .
in the Matthews Patent U.S. 3,722,550 and suitable nylon is ~ ~, disclosed in the Brumbach Patent U.S. 3,062,241.
!`, ~ Any suitable fibrous material or mixtures thereof may ;~ be used to form the reinforcing layers. For example, an ~1 .
aromatic polyamide such as "Kevlar" sold by E.I. duPont de -, Nemours and Company may be used. A poly(alkyleneterephthalate) ester, nylon or the like may be used. Suitable materials are disclosedj for example, in the aforesaid patents. i`
~; 20 Any suitable synthetic polym~r or blend thereof may be ~ ;
~l extruded over one layer to provide an intermediate bonding ;~ layer. The polymer may be, for example, a segmented thermo-' plastic copolyester elastomer such as "Hytrel", nylon, poly-,::
urethane or other thermoplastic polyester or blend thereof.
The layer should be sufficiently thick to provide for the surfaces of the fibers of both laps to be partially embedded ~3 therein and form a mechanical bond. For best results, the i layer will usually be from about 0.003 inch to 0.10 inch thick~
~".
.~ ~, ~': ",. , -, - 6 -;. , r' ~ The protective sheath may be formed by extruding ,.:
any suitable synthetic polymer over the surface of the fibrous reinforcing material. Examples of suitable polymers are nylon, segmented thermoplastic copolyester elastomer and polyurethane.
Best results have been obtained so far with hoses in which the bonding material used between the layers of reinforcing material is a segmented thermoplastic copolyester ... .
elastomer. Such a polyester having a hardness of Shore 90A
~ 10 is preferred because it produces a bond haviny the best peel ,` strength but other polyesters of this type having a hardness o~ Shore 55D and 63D have been used to advantage. In fact, a hose in which the intermediate layer of elastomer has a ~ ' hardness of Shore 63D has given the best overall hose per- ~
;,'. ~, :
formance.
Referring now to the drawingl one embodiment of the ~ :~
hydraulic hose provided by the invention is illustrated in Figures 1 and 2. This hose has a core tube 10 formed by ~ `
;; extruding "Hytrel" having a hardness of Shore 55D and i~ 20 extruding a skin lOa of elastomeric polyurethane over the external surface~of core tube 10. Strands of Kevlar aromatic polyamide fibers having a 1500 denier, a tenacity of about 20 and an elongation of about 4% are wound at ~; a lay of about 52 with the axis of the core tube directly over core tube 10. The core tube 10 has been wet with t solvent for the polyurethane to soften it before the -~
~,. :. ~ , , .
strands are wound thereabout so that the strands become ~;i partially embedded in the surface lOa of core tube 10 and the first layer is mechaniGally bonded thereto. A
;~ ~ 7 ~
'.~.i', ', ' . . :
;:/ : :
~: . :
.~.'.'. :
~ 5'7~
second layer of strands 13 wound in a direction opposite from the winding of layer 11 is disposed about layer ll with an intermediate layer of extruded "Hytrel"
about 0.003 inch thick which mechanically bonds the two layers ll and 13 together. A sheath 14 is extruded over layer 13. A suitable adhesive may be included between layer 13 and the sheath. The sheath may be "~ytrel" or a polyurethane elastomer.
As illustrated in Figure 3 of the drawing, the hose of Figure 1 is formed by first extruding the core tube lO, wetting the core tube sur~ace with a suitable ,. , solvent or plasticizer which will suften the surface ~-.
thereof and winding strands of fibrous material about the core tube to form a first layer ll. A polymer layer 12 is then extruded over layer ll and while this polymer layer !
, is still soft a second layer 13 of fibrous material is ` wound under a tension which will cause the strands to ~ become partially embedded in layer 12 to form a mech^anical '-l bond. A sheath is then 0xtruded over layer 13. The polymer ,,.'~. ~ .
l 20 of the sheath may be ~ured by irradiation with electrons, ; if desired.
Suitable solvents for softening the surface of core tube lO and for adhesively bonding the reinforcing material to the sheath are disclosed, for example, in U.S. Patents 3,726,321 and 3,332,447. Alternately, a hot melt adhesive or a solvent free adhesive of the type disclosed in U.S. Patent 3,1I6,760 may be used.
i~ It has been found that the hose illustrated in Figure l will perform at unusually high temperatures. A hose .~:
,, , ~ - 8 -,^ ' r A
~ "~
having the structure described above with xespect ~o Figure 1, for example, had a burst strength of 20,500 p.s.i. at room temperature and 15,500 p.5.i. at 200F.
A hose made in accordance with the disclosure in U.S.
Patent 3,604,461 to the same dimensions as those used in the hose of the invention, on the other hand, had a burst strength of 22,000 p.sJi. at room temperature but only 14,000 p.s.i. at 200~F. This is an indication that the novel elastomeric layer between layers of reinforcing strands does not permit the fibers to displace at high temperatures so the hose loses less of its burst strength.
It is to be understood that core tube 10 may be ;, extruded from any suitable polymer, other than "Hytrel."
- For example, it may be a nylon core tube which is not bonded to the reinforcing material or it may be a nylon tube 10 having an elastomeric polyurethane skin lOa bonded to the reinforcing material. Moreover, a hot melt adhesive may be used to bond the core tube to the reinforcing material.
An advantage of the hose of this invention is that ~; 20 it can be made with a conventional extruder and avoids the . ~ . .
necessity of making critical adhesive formulations and of accurate control of the processing to ensure proper curing of the adhesive to produce the desired properties.
Although the invention has been described in detail for the purpose o illustration, it is to be understood that such detail is~solely for that purpose and that variations -~
can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.
-:, : ' .
. . _ 9 _ '~
.'.' ,, ~ - .
~ i ,5~7~'76 With the resilient bond mechanism of Matthews, the bonding materials tend to soak in and saturate the fiber layers and eliminate the desired mobility of fibers in the reinforcing layer. The Matthews construction inherently gives a very stiff hose. Any attempts to increase flexibility by making the adhesive more flexible also weakens the bond ; and lowers hose performance. Therefore, the Matthews hose can be stiff with high performance or flexible with low performance, but never both.
It has also been proposed to coat layers of braided insulation with a rubber solution such as, for example in :;. j .
U.S. Patent No. 3,750,712. ~oreover, hoses having helically ~;`, wound layers of wire with a rubber intermediate ply have -1 been disclosed in U.S. Patents No's. 3,506,040; 2,033,559;
.....
l 3,481,368; 3,866,633; 2,237,490 and 2,047,770. In addition, i a hose having wound tape reinforcing is disclosed in U.S. `
Patent No. 1,940,868. Also, a pipe having at least three oppositely wound layers of reinforcing threads bonded by I wetting the threads with a bonding substance or by applying a liquid bonding material to surface of the wound threads is disclosed in U.S. Patent 3,107,698. However, none of the heretofore available hoses have a reinforcing structure ~ :;, 'I
for the core tube which is both flexible and sufficiently strong to provide a high burst strength. ;~
It is an object of this inven$ion to prc)vide a hose i ~ having a synthetic polymeric core tube and reinforcement for r; the core tube which is flexible and effectively supports the ~ core tube against bursting under high fluid pressures.
f~
~,, 5''''4 ' ,' : '~
! , . .' 1~5"~
Another object of the invention is to provide a hose having a synthetic polymeric core tube and oppositely helically ;
, ,. . ~ .
wound reinforcing strands of fibers with an improved bond ~
.. ~ .
between layers of the strands. A further object of the . . ~
invention i5 to provide a hose having oppositely helically wound layers of s~rands of synthetic fiber bonded together with a bonding material which does not modify or destroy the surface of the strands and provides a flexible and strong reinforcing structure for the core tuba.
Other objects will become apparent from the follow-ing description with reference to the accompanying drawing wherein .: ;;
; Figure 1 is a fragmentary side elevation illustrating ~
;. ~ , an embodiment of the invention;
. .~ .
....
;i Figure 2 is a cross-section taken along the line 2-2 i~ of Figure l; and ,, ~
`1 Figure 3 is a diagrammatic illustration of a method of ma!king the hose provided by the invention.
The foregoing objects and others are accomplished -~ 20 in accordance with this invention, generally speaking, by ;: :;
providing a hydraulic hose having an extruded synthetic ;
; polymeric core tube, a first layer or half-lap of helically ;
wound strands of fibroùs material wound in one direction di-rectly against the core tube and mechanically bonded thereto, a second layer of oppositely helically wound strands about the first layer, an extruded layer of flexible elastomeric material ` I disposed between the two layers mechanically bonding the layers together and preferably an extruded synthetic polymeric sheath , ., .
4 ;
,:, :
,. :, :
.
t~
., ~;
about the r~inforcing layers. The hose may have one, two or more pairs of half-laps of helicallY wound strands of fibrous material bonded together with an intermediate polymeric layer.
.: The novel hydraulic hose may be made by extruding :~ a synthetic polymer to form a core tube of indeterminate , ~ ~
; length, softening the surface of the core tube with a solvent , therefor, helically winding a layer of strands of fibrous ~.
~:~ material to form a layer on the core tube while the surface ~: :
.... .
; 10 is still soft at a tension whereby the skrands becomes only ; -partially embedded in the surface, extrud.ing a synthetic . .:
~ polymer over the first layer to form a flexible layer of f~ polymer and winding in a direction opposite from that of the j. fi.rst layer a second layer of strands of fibrous material , over the polymer layer while it is still soft at a.tension ~ ~ whereby the strands becomes only partially embedded therein i~ J to form a mechanical bond between the two layers. Additional . bonded layers may be provided and a sheath may be formed over ;;~
~¦ the surface of reinforcing layers by extruding a polymer ..
. 20 thereover. .:
:1 It has been found that the extruded layer of polymer ~: between the two layers forms a bond at the fiber layer .lnter-.,,, ;
. face with a minimum number of fibers of the strands being restrained so that the fibrous reinforcing material is re-silient and does not appreciably stiffen the tube. At the ~: same time, however, the lapped helically wound reinforcing material provides greater resistance to bursting of the core :~
tube than would a braid containing a similar number of fibers. `~
~ 5 ~ ~
~5~ 7~
~.
Since the extruded layer of polymer is a continuous coherent ~-~
layer of material the mechanical bonding of the two layers `
together does not aepend upon adhesion of the elastomeric layer to the fibers.
The core tube may be extruded from any suitable synthetic polymer such as, for example, an elastomeric poly~
urethane, nylon, a segmented thermoplastic copolyester . ~, , , ~: elastomer, polyvinyl chloride or the like. The segmented ~
.. . .
thermoplastic copolyester elastomer may be the one disclosed in U.S. Patent 3,766,146 or "Hytrel" sold by E.I. duPont de Nemours and Company. Suitable polyurethanes are disclosed .
in the Matthews Patent U.S. 3,722,550 and suitable nylon is ~ ~, disclosed in the Brumbach Patent U.S. 3,062,241.
!`, ~ Any suitable fibrous material or mixtures thereof may ;~ be used to form the reinforcing layers. For example, an ~1 .
aromatic polyamide such as "Kevlar" sold by E.I. duPont de -, Nemours and Company may be used. A poly(alkyleneterephthalate) ester, nylon or the like may be used. Suitable materials are disclosedj for example, in the aforesaid patents. i`
~; 20 Any suitable synthetic polym~r or blend thereof may be ~ ;
~l extruded over one layer to provide an intermediate bonding ;~ layer. The polymer may be, for example, a segmented thermo-' plastic copolyester elastomer such as "Hytrel", nylon, poly-,::
urethane or other thermoplastic polyester or blend thereof.
The layer should be sufficiently thick to provide for the surfaces of the fibers of both laps to be partially embedded ~3 therein and form a mechanical bond. For best results, the i layer will usually be from about 0.003 inch to 0.10 inch thick~
~".
.~ ~, ~': ",. , -, - 6 -;. , r' ~ The protective sheath may be formed by extruding ,.:
any suitable synthetic polymer over the surface of the fibrous reinforcing material. Examples of suitable polymers are nylon, segmented thermoplastic copolyester elastomer and polyurethane.
Best results have been obtained so far with hoses in which the bonding material used between the layers of reinforcing material is a segmented thermoplastic copolyester ... .
elastomer. Such a polyester having a hardness of Shore 90A
~ 10 is preferred because it produces a bond haviny the best peel ,` strength but other polyesters of this type having a hardness o~ Shore 55D and 63D have been used to advantage. In fact, a hose in which the intermediate layer of elastomer has a ~ ' hardness of Shore 63D has given the best overall hose per- ~
;,'. ~, :
formance.
Referring now to the drawingl one embodiment of the ~ :~
hydraulic hose provided by the invention is illustrated in Figures 1 and 2. This hose has a core tube 10 formed by ~ `
;; extruding "Hytrel" having a hardness of Shore 55D and i~ 20 extruding a skin lOa of elastomeric polyurethane over the external surface~of core tube 10. Strands of Kevlar aromatic polyamide fibers having a 1500 denier, a tenacity of about 20 and an elongation of about 4% are wound at ~; a lay of about 52 with the axis of the core tube directly over core tube 10. The core tube 10 has been wet with t solvent for the polyurethane to soften it before the -~
~,. :. ~ , , .
strands are wound thereabout so that the strands become ~;i partially embedded in the surface lOa of core tube 10 and the first layer is mechaniGally bonded thereto. A
;~ ~ 7 ~
'.~.i', ', ' . . :
;:/ : :
~: . :
.~.'.'. :
~ 5'7~
second layer of strands 13 wound in a direction opposite from the winding of layer 11 is disposed about layer ll with an intermediate layer of extruded "Hytrel"
about 0.003 inch thick which mechanically bonds the two layers ll and 13 together. A sheath 14 is extruded over layer 13. A suitable adhesive may be included between layer 13 and the sheath. The sheath may be "~ytrel" or a polyurethane elastomer.
As illustrated in Figure 3 of the drawing, the hose of Figure 1 is formed by first extruding the core tube lO, wetting the core tube sur~ace with a suitable ,. , solvent or plasticizer which will suften the surface ~-.
thereof and winding strands of fibrous material about the core tube to form a first layer ll. A polymer layer 12 is then extruded over layer ll and while this polymer layer !
, is still soft a second layer 13 of fibrous material is ` wound under a tension which will cause the strands to ~ become partially embedded in layer 12 to form a mech^anical '-l bond. A sheath is then 0xtruded over layer 13. The polymer ,,.'~. ~ .
l 20 of the sheath may be ~ured by irradiation with electrons, ; if desired.
Suitable solvents for softening the surface of core tube lO and for adhesively bonding the reinforcing material to the sheath are disclosed, for example, in U.S. Patents 3,726,321 and 3,332,447. Alternately, a hot melt adhesive or a solvent free adhesive of the type disclosed in U.S. Patent 3,1I6,760 may be used.
i~ It has been found that the hose illustrated in Figure l will perform at unusually high temperatures. A hose .~:
,, , ~ - 8 -,^ ' r A
~ "~
having the structure described above with xespect ~o Figure 1, for example, had a burst strength of 20,500 p.s.i. at room temperature and 15,500 p.5.i. at 200F.
A hose made in accordance with the disclosure in U.S.
Patent 3,604,461 to the same dimensions as those used in the hose of the invention, on the other hand, had a burst strength of 22,000 p.sJi. at room temperature but only 14,000 p.s.i. at 200~F. This is an indication that the novel elastomeric layer between layers of reinforcing strands does not permit the fibers to displace at high temperatures so the hose loses less of its burst strength.
It is to be understood that core tube 10 may be ;, extruded from any suitable polymer, other than "Hytrel."
- For example, it may be a nylon core tube which is not bonded to the reinforcing material or it may be a nylon tube 10 having an elastomeric polyurethane skin lOa bonded to the reinforcing material. Moreover, a hot melt adhesive may be used to bond the core tube to the reinforcing material.
An advantage of the hose of this invention is that ~; 20 it can be made with a conventional extruder and avoids the . ~ . .
necessity of making critical adhesive formulations and of accurate control of the processing to ensure proper curing of the adhesive to produce the desired properties.
Although the invention has been described in detail for the purpose o illustration, it is to be understood that such detail is~solely for that purpose and that variations -~
can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.
-:, : ' .
. . _ 9 _ '~
.'.' ,, ~ - .
Claims (14)
1. A hydraulic hose comprising an extruded synthetic polymeric core tube, a first layer of helically wound strands of fibrous material disposed about the core tube, a second layer of oppositely wound helical strands of fibrous material disposed about the first layer and an intermediate layer of extruded polymer between the said first and second layers mechanically bonding them together.
2. The hydraulic hose of Claim 1 wherein the said intermediate layer is a thermoplastic segmented copolyester elastomer.
3. The hydraulic hose of Claim 2 wherein the said strands in both layers are aromatic polyamide.
4. The hydraulic hose of Claim 1 having a protective sheath.
5. The hydraulic hose of Claim 1 wherein the core tube is bonded to the fibrous reinforcing material.
6. The hydraulic hose of Claim 4 wherein the protective sheath is bonded to the outermost layer of helically wound fibrous reinforcement strands.
7. The hydraulic hose of Claim 1 wherein the helically wound fibrous reinforcement is selected from the group consisting of aromatic polyamide, nylon and poly (alkyleneterephthalate) ester.
8. The hydraulic hose of Claim 1 wherein the helically wound fibrous reinforcement is selected in combination from at least two of the members of the group consisting of aromatic polyamide, nylon and poly (alkyleneterephthalate) ester.
9. The hydraulic hose of Claim 1 wherein the core tube is segmented copolyester, thermoplastic polyester, nylon or polyurethane.
10. The hydraulic hose of Claim 1 wherein the core tube is a blend of at least two polymers.
11. A hydraulic hose comprising an extruded synthetic polymeric core tube, a first layer of strands of fibrous reinforcing material helically wound in one direction directly against the core tube and bonded thereto, a second layer of strands of fibrous reinforcing material helically wound in a direction opposite to that of the strands of the first layer, and an extruded layer of polymer between the two oppositely wound layers of reinforcing material, the said strands of both layers being only partially embedded in the said extruded layer whereby the extruded layer forms a mechanical bond which is substantially free from adhesive bonding between the layers of fibrous material and the layers of fibrous material form a resilient reinforcement for the core tube which provides the hose with an improved burst strength at temperatures above conventional room temperatures.
12. A method for reducing loss in burst strength of a core tube of a hydraulic hose under pressure at temperatures above room temperature which comprises reinforcing the core tube with a first layer of strands of fibrous reinforcing material wound in one direction directly against the core tube, extruding a polymer layer over the said first layer and helically winding a second layer of fibrous reinforcing material wound in a direction opposite to that of the first layer over the polymer layer, whereby the strands in the said first and second layers are only partially embedded in the extruded layer and are mechanically bonded thereto.
13. A method for making a hydraulic hose having improved resistance to bursting under pressure comprising helically winding a first layer of strands of fibrous reinforcing material about a core tube, extruding a layer of polymer over the said first layer, and helically winding a second layer of strands of fibrous reinforcing material against the said extruded layer, whereby strands of the said first and second layers become only partially embedded in the extruded layer to resiliently bond the layers together mechanically.
14. A hydraulic hose comprising an extruded synthetic polymeric core tube, a first layer of helically wound strands of fibrous material disposed about the core tube, a second layer of oppositely wound helical strands of fibrous material disposed about the first layer and an intermediate continuous layer of polymer disposed between the two layers of fibrous material separating the layers of fibrous material and mechani-cally bonding them together.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US61608275A | 1975-09-23 | 1975-09-23 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1057676A true CA1057676A (en) | 1979-07-03 |
Family
ID=24467959
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA253,787A Expired CA1057676A (en) | 1975-09-23 | 1976-06-01 | Hydraulic hose |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS5240820A (en) |
| BE (1) | BE843521A (en) |
| CA (1) | CA1057676A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2597568B1 (en) * | 1986-04-18 | 1988-07-08 | Tecalemit Flexibles | NOVEL FLEXIBLE PIPE FOR USE AT HIGH PRESSURE AND MANUFACTURING METHOD THEREOF |
| JPH01164886A (en) * | 1987-12-17 | 1989-06-28 | Nichirin Rubber Kogyo Kk | Hydraulic brake hose for automobile |
| JPH0439487U (en) * | 1990-07-31 | 1992-04-03 |
-
1976
- 1976-06-01 CA CA253,787A patent/CA1057676A/en not_active Expired
- 1976-06-28 BE BE168406A patent/BE843521A/en unknown
- 1976-07-05 JP JP8032776A patent/JPS5240820A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5240820A (en) | 1977-03-30 |
| BE843521A (en) | 1976-10-18 |
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