U.S. patent application number 11/389954 was filed with the patent office on 2007-09-27 for high-pressure resistant hose.
Invention is credited to Eiichi Daikai.
Application Number | 20070221283 11/389954 |
Document ID | / |
Family ID | 38456788 |
Filed Date | 2007-09-27 |
United States Patent
Application |
20070221283 |
Kind Code |
A1 |
Daikai; Eiichi |
September 27, 2007 |
HIGH-PRESSURE RESISTANT HOSE
Abstract
A hose base body of multilayered construction including an inner
surface layer, a reinforcing layer and an outer surface layer has
uniform inner diameter, outer diameter and wall-thickness over an
entire length thereof. A longitudinal end portion of the hose base
body is diametrically expanded, and a main hose body is formed with
a small diameter main portion, a large diameter swaged portion and
a tapered portion. A braid angle of the reinforcing layer is
designed 48.degree. to lower than 54.degree. on the main portion, a
braid angle of the reinforcing layer is designed over 57.degree. to
68.degree. on the tightened portion, and a braid angle of the
reinforcing layer is designed over about 55.degree. to 61.degree.
on the tapered portion.
Inventors: |
Daikai; Eiichi; (Nagoya-shi,
JP) |
Correspondence
Address: |
ANDRUS, SCEALES, STARKE & SAWALL, LLP
100 EAST WISCONSIN AVENUE, SUITE 1100
MILWAUKEE
WI
53202
US
|
Family ID: |
38456788 |
Appl. No.: |
11/389954 |
Filed: |
March 27, 2006 |
Current U.S.
Class: |
138/124 ;
138/109; 138/123 |
Current CPC
Class: |
B29D 23/001 20130101;
B29K 2995/0069 20130101; F16L 11/081 20130101; F16L 11/085
20130101; F16L 33/2076 20130101; B29K 2019/00 20130101; B29L
2031/3055 20130101; B29C 57/04 20130101; B29C 53/58 20130101 |
Class at
Publication: |
138/124 ;
138/123; 138/109 |
International
Class: |
F16L 11/00 20060101
F16L011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 22, 2006 |
JP |
2006-079822 |
Mar 22, 2006 |
JP |
2006-079823 |
Claims
1. A high-pressure resistant hose with bursting pressure equal to
or greater than 5 MPa, comprising: a main hose body of
multi-layered construction including an inner surface side layer, a
reinforcing layer comprising a braided or spirally wound
reinforcing filament member on outer side of the inner surface side
layer and an outer surface side layer as cover layer on an outer
side of the reinforcing layer, the main hose body having a main
portion, and a tightened portion with diameter larger than that of
the main portion on a longitudinal end portion of the main hose
body, a joint device fixedly secured to the tightened portion, the
joint device having an insert pipe inserted in the tightened
portion with diameter larger than that of the main portion, and a
tightening fitting fitted on an outer periphery of the tightened
portion for tightening the tightened portion to the insert pipe,
wherein the main hose body further has a tapered portion between
the tightened portion and the main portion, wherein the braided or
spirally wound reinforcing filament member of the reinforcing layer
has an angle of 48.degree. to lower than 54.degree. on the main
portion , an angle of over 57.degree. to 68.degree. on the
tightened portion and an angle of over about 55.degree. to
61.degree. on the tapered portion, wherein the angle of the braided
or spirally wound reinforcing filament member on the tapered
portion is lower than the angle of the braided or spirally wound
reinforcing filament member on the tightened portion, and wherein a
ratio of a length of the main portion with respect to a free length
of the main hose body is 65% to 93% under pressureless
condition.
2. A high-pressure resistant hose as set forth in claim 1, wherein
the braided or spirally wound reinforcing filament member of the
reinforcing layer has an angle of 60.degree. to 68.degree. on the
tightened portion.
3. A high-pressure resistant hose as set forth in claim 1, wherein
the braided or spirally wound reinforcing filament member of the
reinforcing layer has an angle of over about 55.degree. to
60.degree. on the tapered portion
Description
TECHNICAL FIELD
[0001] 1. Field of the Invention
[0002] The present invention relates to a high-pressure resistant
hose such as an automotive air conditioning hose and a method for
producing such high-pressure resistant hose.
[0003] 2. Description of the Related Art
[0004] A hose used for an automotive air conditioning hose has such
construction that a reinforcing layer is formed from a reinforcing
filament member or reinforcing yarn (for example, spirally wound
reinforcing filament member) on an outer side of an inner surface
side layer made of rubber, and an outer side of the reinforcing
layer is covered with an outer surface side layer made of rubber
(for example, refer to Patent Document 1). Such type of a hose is
often provided with a resin barrier layer on an inner side of the
inner surface side layer in order to prevent global warming by
reducing permeation of an internal fluid, i.e. a refrigerant.
[0005] Since such air conditioning hose is used for connecting
between an engine side and a vehicle body side, the air
conditioning hose is preferably provided with vibration absorbing
property sufficient to prohibit transmission of vibration, such as
engine vibration, compressor vibration or vehicle body vibration
during driving to mating components. However, formation of the
resin barrier layer improves resistance of the air conditioning
hose to refrigerant permeation, but lowers such vibration absorbing
property or vibration damping property. So, it is required to form
the air conditioning hose long (for example, even when a hose is
adapted for connecting distance of about 300 mm, the hose is formed
about 400 mm in length) so that formation of the resin barrier
layer does not cause lack of vibration absorbing property in the
air conditioning hose or does not reduce vibration absorbing
property of the air conditioning hose.
[0006] However, in many cases, an engine room of a motor vehicle is
tightly packed with parts, etc., and cannot afford or secure
sufficient piping space. So, it is often disadvantageous to take
such measures as formation of the resin barrier layer and increase
of a hose length. Then, it is conceived to form the air
conditioning hose as short as possible, instead of formation of the
resin barrier layer. When the hose is sufficiently short, the
refrigerant permeation through the hose or and from the hose can be
lowered. And, when the hose is constructed to have a short length
but secure sufficient vibration absorbing property, it is possible
to provide the air conditioning hose which can be accommodated in a
narrow piping space, is low in refrigerant permeation and good in
vibration absorbing property.
[0007] By the way, in the air conditioning hose, when a refrigerant
is introduced in the hose at high pressure, lack of the vibration
absorbing property is caused. When the refrigerant is not
introduced in the hose, the vibration absorbing property almost
does not matter. Namely, when the refrigerant is supplied in the
hose at high pressure, the hose and the refrigerant are unified,
thereby the hose is rigidified, and this results in lack of the
vibration absorbing property. And this rigidification of the hose
depends on a cross-sectional area of an inside of the hose (an area
of a cross-section or cutting plane of the hose in a radial
direction). The larger the cross-sectional area is, the more the
hose is rigidified, and, the smaller the cross-sectional area is,
the less the hose is rigidified.
[0008] Then, it may be conceived to form a small-diameter air
conditioning hose in order to secure the vibration absorbing
property. However, on an end portion of the air conditioning hose
(main hose body), a joint device, for example, including an insert
pipe and a socket fitting (tightening fitting), is attached. When
the main hose body has a small-diameter over its entire length, the
insert pipe of the joint device has to be inserted in an end
portion (a tightened or to-be-tightened portion, more specifically,
a swaged or to-be-swaged portion) of the main hose body, while
diametrically expanding the swaged portion (a portion to be
tightened by the socket fitting that is swaged). But, the air
conditioning hose is typically has a bursting pressure of 5 MPa or
more, insertion resistance becomes too great and it is practically
difficult to insert the insert pipe in the end portion of the main
hose body.
[0009] In order to solve a foregoing problem, it is conceived to
adapt means to produce a main hose body including a small-diameter
main portion and a large diameter swaged portion. The insert pipe
is inserted in the swaged portion that has a diameter larger than
that of the main portion, the socket fitting fitted on an outer
periphery of the swaged portion is swaged to tighten (swage) the
swaged portion to the insert pipe. In this regard, for example,
Patent Documents 2 and 3 disclose a technique that a connecting
portion of a hose with a pipe is formed with large diameter, in
advance. TABLE-US-00001 [Patent Document 1] JP-A, 7-68659 [Patent
Document 2] JP-B, 3244183 [Patent Document 3] JP-B, 8-26955
[0010] Meanwhile, the air conditioning hose to be arranged in the
narrow piping space should exhibit a small length change rate (in
absolute value) when a pressure-fluid, i.e., a refrigerant is
supplied therein. If the length change rate under exerted pressure
is large, a hose changes largely in length when pressurizing
refrigerant is supplied, the hose contacts or abuts peripheral
parts, etc. or is pressed firmly against the peripheral parts, etc.
As a result, there is fear that the hose is damaged or the hose
gets out of the piping space. And, the length change rate of the
hose under exerted pressure depends on braid angle or winding angle
of a reinforcing yarn of the reinforcing layer. That is, in the
hose, the braid or winding angle tends to return to about
55.degree. (54.7.degree., neutral angle) when an internal pressure
is applied. So, when the braid or winding angle is lower than about
55.degree., the hose tends to change so as to expand in a radial
direction and so as to contract in a longitudinal direction under
exerted pressure. Further, when the braid or winding angle is
greater than about 55.degree., the hose tends to change so as to
increase in length in the longitudinal direction and so as to
contract in the radial direction under exerted pressure. When the
braid or winding angle is about 55.degree. (54.7.degree., neutral
angle), the hose is prevented from change in the longitudinal
direction and the radial direction even under exerted pressure. So,
in case that the tightened portion or swaged portion of the main
hose body is diametrically enlarged, it is necessary to prevent
increase of the length change rate (in absolute value) of the hose
or the main hose body under exerted pressure by adjusting the braid
or winding angle of the reinforcing filament member on the main
portion, the tapered portion and the swaged portion, respectively,
and a relation between lengths of these portions.
[0011] The main hose body including a small diameter main portion
and a large diameter swaged portion is obtained in such manner
that, a hose base body is formed so as to have a uniform diameter
equal to that of the main portion, over its entire length,
longitudinal opposite end portions of the hose base body are
diametrically expanded by press inserting mandrels into the
longitudinal opposite end portions to form into large-diameter
swaged portions. In order to prevent that the mandrel cannot be
press inserted in longitudinal opposite end portions of the hose
base body due to buckling of the hose base body, it is necessary to
retain a longitudinal middle portion of the hose base body by or in
a retaining mold. The retaining mold comprises a plurality of
retaining mold segments, the retaining mold segments are mated
together to define a receiving portion. The hose base body is
firmly sandwiched and retained by the receiving portion on the
longitudinal middle portion.
[0012] It is effective that the receiving portion defined by mated
mold segments has a cross-sectional shape so as to compress the
hose base body. When the receiving portion compresses or is
compressing the hose base body, the hose base body is prevented or
restrained from expanding in the radial direction within the
receiving portion. So, buckling is not caused when the mandrel is
press inserted in the hose base body.
[0013] However, when the receiving portion is defined so as to
compress the hose base body, there is fear that material of an
outer surface side layer is pushed out from between the retaining
mold segments at time of mating contact of the retaining mold
segments, and flash is formed on the main hose body produced. This
makes post treatment after the main hose body is produced
troublesome.
[0014] In order to solve a foregoing problem, it is an object of
the present invention to provide a novel high-pressure resistant
hose having a good vibration absorbing property, for example, that
exhibits a small length change rate or amount under exerted
pressure and/or can be arranged stably in the narrow piping
space.
[0015] And, it is another object of the present invention to
provide a method for producing a high-pressure resistant hose
wherein buckling of the hose base body can be prevented when
diametrically expanding the longitudinal end portions of the hose
base body and/or bothersome posttreatment of the main hose body is
not required.
SUMMARY OF THE INVENTION
[0016] According to the present invention, there is provided a
novel high-pressure resistant hose. The high-pressure resistant
hose has bursting pressure equal to or greater than 5 MPa. The
high-pressure resistant hose comprises a main hose body of
multi-layered construction that includes an inner surface side
layer, a reinforcing layer comprising a braided or spirally wound
reinforcing filament member on outer side of the inner surface side
layer and an outer surface side layer as cover layer on an outer
side of the reinforcing layer, and a joint device. The main hose
body has a main portion, and a tightened portion or to-be-tightened
portion with diameter larger than that of the main portion on a
longitudinal end portion (for example, each of opposite
longitudinal end portions) of the main hose body. The joint device
is fixedly secured to the tightened portion, and has an insert pipe
that is inserted in the tightened portion with diameter larger than
that of the main portion, and a tightening fitting that is fitted
on an outer periphery of the tightened portion for tightening the
tightened portion to the insert pipe. The main hose body further
has a tapered portion between the tightened portion and the main
portion. The braided or spirally wound reinforcing filament member
of the reinforcing layer has an angle (braid or winding angle) of
48.degree. to lower than 54.degree. on the main portion, an angle
(braid or winding angle) of over 57.degree. to 68.degree. on the
tightened portion and an angle (braid or winding angle) of over
about 55.degree. (neutral angle) to 61.degree. on the tapered
portion. The braid or winding angle of the reinforcing filament
member on the tapered portion is lower than the angle of the
braided or spirally wound reinforcing filament member on tightened
portion, and a ratio of a length (an axial length) of the main
portion with respect to a free length (a free axial length) of the
main hose body is 65% to 93% under pressureless condition. Here,
the main hose body is molded or formed with the tightened portion
being diametrically expanded. So, the insert pipe of the joint
device is to be inserted in the tightened portion that is
diametrically expanded. Therefore, for example, in the
high-pressure resistant hose with the bursting pressure equal to or
greater than 5 MPa where the braided or wound reinforcing filament
member of the reinforcing layer has a density (braid or winding
density) equal to or greater than 50%, even when a main portion
comprising a major part or long region or the like of the main hose
body has a small diameter to increase vibration absorbing property,
it is not difficult to attach the joint device to the main hose
body (the tightened portion), more specifically to insert or press
insert the insert pipe in the main hose body (the tightened
portion). An outer diameter of the insert pipe may be set equal to
or generally equal to an inner diameter (diametrically expanded
inner diameter) of the tightened portion prior to insertion of the
insert pipe. The reinforcing layer may comprise a braided
reinforcing filament member, or may also comprise a spirally wound
reinforcing filament member. A braid or winding density means a
ratio (%) of an area of the reinforcing filament member with
respect to an overall area of the reinforcing layer. More
specifically, the braid or winding density can be given by a
formula (yarn width.times.No. of yarns/(2.times..pi..times.outer
diameter of the inner surface side layer or of a layer just under
the reinforcing layer.times.cos. braid or winding
angle)).times.100. On the tapered portion, in fact, a braid or
winding angle is changed from the braid or winding angle of the
main portion to the braid or winding angle of the tightened
portion, from an end of the main portion toward an end of the
tightened portion. However, the braid or winding angle of the
tapered portion with regard to the present invention means a braid
or winding angle at an axial center of the tapered portion.
[0017] The main hose body is constructed, for example, in a
following manner. First, prepared or produced is a hose base body,
which includes a reinforcing layer, and has a uniform diameter over
its entire length. The reinforcing layer comprises the braided or
wound reinforcing filament member or yarn and has a uniform braid
or winding angle over its entire length. And a longitudinal end
portion (for example, longitudinal opposite end portions) of the
hose base body is diametrically expanded. The braid or winding
angle means an angle of the reinforcing-filament member or yarn
with respect to an axis of a hose. According to the present
invention, braided or spirally wound filament member or yarn of the
reinforcing layer has an angle (braid angle or winding angle) of
48.degree. to lower than 54.degree. on the main portion (namely, a
hose base body). So, an end portion (for example, longitudinal
opposite end portions) of the hose base body can be easily
diametrically expanded, after the hose base body is produced. And,
when an internal pressure is exerted in a main hose body, the main
portion changes so as to reduce in length. Here, when the braided
or spirally wound reinforcing filament member of the reinforcing
layer has an angle lower than 48.degree. on the main portion, the
main portion contracts largely in length under pressure exerted to
the main hose body. So, in order to restrain length change ratio of
an entire free region of the main hose body under exerted pressure
small, it is necessary to form long tapered portion and tightened
portion where the braided or spirally wound reinforcing filament
member of the reinforcing layer has an angle over neutral angle.
Then, it becomes bothersome to handle a hose or difficult to
arrange the hose in a narrow piping space. And, when the braided or
spirally wound reinforcing filament member of the reinforcing layer
has an angle equal to or greater than 54.degree. on the main
portion, resistance to diametrical expansion is increased in case
of diametrically expanding the end portion of the hose base body, a
length change ratio under exerted pressure becomes large, and it
becomes bothersome to handle the hose.
[0018] An angle of the braided or spirally wound reinforcing
filament member of the reinforcing layer is set over 57.degree. to
68.degree. on the tightened portion, and over about 55.degree.
(more specifically, over 54.7.degree. or neutral angle) to
61.degree. on the tapered portion. Thus, when the internal pressure
is exerted in the main hose body, the main portion changes so as to
reduce in length, while the tightened portion and the tapered
portion change so as to increase in length. Thus, the length change
rate (length change rate under exerted pressure, absolute value) of
whole of the main hose body (entire free region of the main hose
body) can be restrained small. When the angle of the braided or
spirally wound reinforcing filament member of the reinforcing layer
is equal to or lower than 57.degree. on the tightened portion, the
tightened portion does not change so as to increase in length to an
extent necessary to counter change of the main portion under
exerted pressure. So, there is fear that the length change rate (in
absolute value) of the entire free region of the main hose body
becomes large. And, it is difficult to diametrically expand the
tightened portion (the longitudinal end portion or longitudinal
opposite end portions of the hose base body) until the angle of the
braided or spirally wound reinforcing filament member exceeds
68.degree.. Similarly, when the angle of the braided or spirally
wound reinforcing filament member of the reinforcing layer is equal
to or lower than about 55.degree. (more specifically, 54.7.degree.
or neutral angle) on the tapered portion, the tapered portion does
not change so as to increase in length under exerted pressure. So,
there is fear that the length change rate (in absolute value) of
the entire free region of the main hose body becomes large. And,
when the angle of the braided or spirally wound reinforcing
filament member of the reinforcing layer is over 61.degree. on the
tapered portion, the angle of the braided or spirally wound
reinforcing filament member becomes too great on the main portion
or the tightened portion. In the hose including the small diameter
main portion (an inner diameter of the main portion is about 9 mm,
or 9 mm to 11 mm) to be subject to high internal pressure, it is
effective that the braided or spirally wound reinforcing filament
member of the reinforcing layer has an angle of 66.degree. to
68.degree. on the tightened portion in order to restrain the length
change rate (in absolute value) of the entire free region small.
When the braided or spirally wound reinforcing filament member of
the reinforcing layer has an angle equal to or lower than
60.degree. on the tapered portion, it becomes possible to restrain
the length change ratio (in absolute value) of the entire free
region smaller.
[0019] In particular, a sealing performance between the main hose
body and the joint device (the insert pipe) is improved by
designing the tightening portion to be diametrically contracted
under exerted pressure.
[0020] A ratio of a length of the main portion with respect to the
free length (unrestrained length) of the main hose body, for
example, a length of a region (portion) of the main hose body
between parts tightened by the joint devices (for example, swaged
parts), or a length of a region (portion) of the main hose body
between innermost positions of the parts tightened by the joint
device (for example, innermost positions of swaged parts) is
required to be 65% to 93% under pressureless condition. When the
ratio of the length of main portion with respect to the free length
of the main hose body is less than 65%, length change of the
tightened portion and the tapered portion too much affects the
length change ratio of the whole of the main hose body (the entire
free region of the main hose body), there is fear that a length
change ratio (in absolute value) of the whole of the main hose body
becomes large. When the ratio of the length of main portion with
respect to the free length of the main hose body is greater than
93%, length change of the tightened portion and the tapered portion
too little affects the length change ratio of the whole of the main
hose body (the entire free region of the main hose body), or length
change of the main portion too much affects the length change ratio
of the whole of the main hose body, there is also fear that the
length change ratio (in absolute value) of the whole of the main
hose body becomes large. And, Meanwhile, when the free length of
the main hose body is over 300 mm under pressureless condition, it
is difficult to arrange the high-pressure resistant hose in the
narrow piping space and a permeation amount of the internal fluid
is increased.
[0021] The free region of the main hose body preferably has a
length change ratio under exerted pressure in a range of -5% to
10%. The length change ratio is given by a formula ((free length of
the main hose body under exerted pressure-free length of the main
hose body prior to exertion of pressure)/free length of the main
hose body prior to exertion of pressure).times.100. When the length
change ratio is under -5%, the main hose body contracts too much in
a longitudinal direction under exerted pressure and the
high-pressure resistant hose is under tension state. So, there is
fear that a large stress is generated in the tightened portion, and
thereby durability of a hose is lowered. And when the length change
ratio is over 10%, the main hose body too much expands in the
longitudinal direction under exerted pressure, so there is fear
that the high-pressure resistant hose contacts or abuts with the
peripheral parts, etc. and gets out of the piping space.
[0022] According to the present invention, there is provided a new
method for producing a high-pressure resistant hose. The
high-pressure resistant hose, which is produced, comprises a main
hose body of multi-layered construction that includes an inner
surface side layer, a reinforcing layer comprising a braided or
spirally wound reinforcing filament member or reinforcing yarn on
an outer side of the inner surface side layer and an outer surface
side layer as cover layer on an outer side of the reinforcing
layer, and a joint device. The main hose body has a main portion,
and a tightened portion or to-be-tightened portion with diameter
larger than that of the main portion on a longitudinal end portion
(for example, each of longitudinal opposite end portions) of the
main hose body. The joint device is fixedly secured to the
tightened portion. The joint device has an insert pipe that is
inserted in the tightened portion with diameter larger than that of
the main portion, and a tightening fitting that is fitted on an
outer periphery of the tightened portion for tightening the
tightened portion to the insert pipe. The method for producing such
a high-pressure resistant hose in accordance with the present
invention, comprises a step of preparing a hose base body of the
multilayered construction that includes the inner surface side
layer, the reinforcing layer and the outer surface side layer, and
of uniform inner diameter, outer diameter and wall-thickness over
an entire length thereof, a step of retaining the hose base body by
a retaining mold (retaining member) such that a longitudinal end
portion thereof (for example, each of the longitudinal opposite end
portions) protrudes outwardly from the retaining mold, a step of
push inserting a mandrel (a diametrically expanding member or rod)
into the longitudinal end portion (for example, each of the
longitudinal opposite end portions) of the hose base body that is
retained by the retaining mold and diametrically expanding the
longitudinal end portion (for example, each of the longitudinal
opposite end portions) to form the tightened portion, a step of
vulcanizing the hose base body with the tightened portion formed to
obtain the main hose body, and a step of securely fixing the joint
device to the tightened portion of the main hose body. The
retaining mold comprises a plurality of retaining mold segments
that are formed with element recesses, respectively. The retaining
mold segments are configured so as to be mated together to provide
the retaining mold with a receiving portion (cavity) that receives
and retains the hose base body. The receiving portion is defined by
the combined element recesses. The element recess may be provided
in the retaining mold segment over an entire length thereof, and
the receiving portion may be provided in the retaining mold,
extending therethrough in a longitudinal direction. The receiving
portion receives the hose base body compressively, and the
receiving portion includes an escape portion that allows a deformed
portion of the hose base body compressed to escape therein. The
high-pressure resistant hose that is produced has a bursting
pressure, for example, equal to or greater than 5 MPa. In the
high-pressure resistant hose, the reinforcing layer may comprise a
braided reinforcing filament member, and also may comprise a
spirally wound reinforcing filament member. The braided or spirally
wound reinforcing filament member of the reinforcing layer may have
a density equal to or greater than 50%. And, the main hose body may
be formed with a tapered portion between the tightened portion and
the main portion. Further, the high-pressure resistant hose may be
constructed such that the braided or spirally wound filament member
or yarn of the reinforcing layer has an angle (braid or winding
angle) of 48.degree. to lower than 54.degree. on the main portion,
an angle (braid or winding angle) of over 57.degree. to 68.degree.
(for example, an angle of 66.degree. to 68.degree.) on the
tightened portion, and an angle (braid or winding angle) of over
about 55.degree. (more specifically, over 54.7.degree. or neutral
angle) to 61.degree. (for example, 60.degree. or lower) on the
tapered portion. And, the high-pressure resistant hose may be
constructed such that a ratio of a length of the main portion with
respect to a free length of the main hose body is 65% to 93% under
pressureless condition, and a free length of the main hose body is
equal to or less than 300 mm under the pressureless condition. The
free region of the main hose body may have a length change ratio
under exerted pressure in a range -5% to 10%.
[0023] When the restraining mold segments are mated together, the
element recesses are combined with the hose base body therebetween
and defines a receiving portion for receiving the hose base body
therein. The receiving portion is formed so as to compress the hose
base body. So, when the element recesses are combined, the hose
base body is compressed, pushed down, tightened or sandwiched
tightly. Thus, the hose base body is received in restrained
relation within the receiving portion defined by the retaining mold
segments. When the element recesses are mated together to define
the receiving portion, since the hose base body is compressed, the
hose base body is deformed and a material of the hose base body is
moved. However, a deformed portion of the hose base body escapes in
an escape portion that is formed in the receiving portion, and
thereby the material of the hose base body does not go out of
between the retaining mold segments. It is effective to form the
escape portion or escape portions on mating contact positions
(positions of mold mating surfaces) or straddling over two
restraining mold segments.
[0024] In order to simplify construction, the retaining mold may
comprise a pair of mold halves or mold segments (retaining mold
segments). Here, the element recesses may be formed into
semicircular cross-section, respectively, so as to form the
receiving portion that has a circular cross-section with a diameter
smaller than an outer diameter of the hose base body. In this
configuration, the hose base body can be firmly retained in the
receiving portion. And, each of the element recesses may have
shallow element slots in opposite side edge portions thereof for
forming the escape-portions on opposite sides of the receiving
portion. In this configuration, a deformed portion of the hose body
can be effectively let out into the escape portion that is formed
at the mating contact position without allowing the material of the
hose base body to get out of the receiving portion. The element
slot may be provided in the retaining mold segment over an entire
length thereof, and the escape portion may be provided in the
retaining mold, extending therethrough in a longitudinal direction
or generally over an entire length thereof.
[0025] The element recesses may be formed into semioval or
semiellipse cross-section, respectively, so as to define the
receiving portion that has an oval or ellipse cross-section with a
minor axis (shortest diameter) smaller than an outer diameter of
the hose base body, in a mating contact direction of the retaining
mold segments and a major axis (longest diameter) longer than the
outer diameter of the hose base body, perpendicular to the minor
axis. In this configuration, the hose base body can be also firmly
retained in the receiving portion. Here, the receiving portion has
the escape portions on or around opposite end positions of the
major axis. The escape portions are located in mating contact
positions.
[0026] An insertion aid may be applied between the longitudinal end
portion of the hose base body and the mandrel. Then, an insertion
resistance acting on the mandrel can be reduced, and the mandrel
can be easily pushed in or push inserted in the longitudinal end
portion.
[0027] As described, according to the present invention, it is
possible to provide a high-pressure resistant hose that has an
excellent vibration absorbing property, for example, can restrain
permeation amount of an internal fluid small, and can be stably
arranged in a narrow piping space.
[0028] And, further, according to the present invention, can be
easily produced the high-pressure resistant hose including a large
diameter tightened portion on which a joint device is securely
fixed.
[0029] Now, the preferred embodiments of the present invention will
be described in detail with reference to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 is a perspective view of a high-pressure resistant
hose according to the present invention.
[0031] FIG. 2 is a view showing a multilayered construction of a
main hose body of a main hose body of the high-pressure resistant
hose.
[0032] FIG. 3 is a sectional view of the high-pressure resistant
hose.
[0033] FIG. 4 is a view showing a hose base body.
[0034] FIG. 5 is a view showing a construction of a retaining
mold.
[0035] FIG. 6 is a view showing a state that the hose base body is
retained by the retaining mold.
[0036] FIG. 7 is a view showing a construction of a receiving
portion when the hose base body is retained by the retaining
mold.
[0037] FIG. 8 is a view showing a construction of another receiving
portion.
[0038] FIG. 9 is a view showing a mandrel.
[0039] FIG. 10 is a view showing a state that the mandrel is
inserted in the hose base body.
[0040] FIG. 11 is a view showing a main hose body.
DETAILED DESCRIPTIONS OF PREFERRED EMBODIMENTS
[0041] A high-pressure resistant hose 1 shown in FIG. 1 is used,
for example, as an air conditioner hose of a motor vehicle. The
high-pressure resistant hose 1 includes a main hose body 3 where
metal joint device (coupling or fitting) 5 are securely fitted to
longitudinal opposite ends thereof, respectively. The main hose
body 3 has a main portion 7 on a longitudinal middle portion
thereof, swaged portions or to-be-swaged portions (tightened
portions) 9, 9 on longitudinal opposite end portions thereof, and
tapered portions 11, 11 each between the main portion 7 and the
swaged portion 9. The main portion 7 is formed in a long-slim
tubular shape having uniform inner and outer diameters over its
entire length thereof. Each of the swaged portion 9 has a tubular
shape with inner and outer diameters larger than those of the main
portion 7. Each of the tapered portions 11 has a tapered shape
gradually reducing a diameter from the swaged portion 9 to the main
portion 7.
[0042] As shown in FIG. 2, the main hose body 3 has a multilayered
construction over its entire length including an inner surface side
layer (inner surface layer) 13 made of rubber, a reinforcing layer
15 formed by braiding a reinforcing yarn (reinforcing filament
member) on an outer periphery of the inner surface side layer 13,
and an outer surface side layer (outer surface layer) 17 made of
rubber and formed on an outer periphery of the reinforcing layer
15. The reinforcing layer 15 is formed directly on the outer
periphery of the inner surface side layer 13, and the outer surface
side layer 17 is formed directly on the outer periphery of the
reinforcing layer 15. Meanwhile, reference character .theta.
indicates a braid or winding angle of a reinforcing filament member
with respect to an axis of a hose.
[0043] The joint device 5 has a metal insert pipe 19 that is
inserted in the swaged portion 9 of the main hose body 3, and a
metal socket fitting (tightening fitting) 21 that is fitted on an
outer periphery of the swaged portion 9. On an outer periphery of
an axially outer end portion of the insert pipe 19, a metal nut 23
for connection is fitted rotatably in locked relation. The metal
nut 23 includes internally threaded inner peripheral surface. As
well shown in FIG. 3, the insert pipe 19 includes an annular groove
25 on an outer peripheral surface thereof for securely fixing the
socket fitting 21 to the insert pipe 19. The insert pipe 19 is
inserted in the swaged portion 9 so as to locate the annular fixing
groove 25 outside an axial end surface of the main hose body 3,
more specifically to locate the annular groove 25 outside the axial
end surface of the main hose body 3 and adjacent to the axial end
surface thereof. And, the socket fitting 21 has a sleeve 27 and an
inwardly directed flange 29 that is formed integrally on an axially
outer end portion of the sleeve 27. The sleeve 27 of the socket
fitting 21 is fitted on the outer periphery of the swaged portion 9
so as to locate the inwardly directed flange 29 outside the axial
end surface of the main hose body 3, corresponding to the annular
groove 25 of the insert pipe 19. By swaging the sleeve 27, the
sleeve 27 tightens or swages the swaged portion 9 to the insert
pipe 19, the inwardly directed flange 29 enters in the annular
groove 25, and the socket fitting 21 is fixed to the insert pipe 19
in unitary relation. Meanwhile, the sleeve 27 is swaged at three
positions (A, B, C) along its length, respectively, and the swaged
portion 9 is tightened at these three positions (A, B, C),
respectively. A portion of the main hose body 3 between the
innermost swaged positions C, C in swaged region from the position
A to the position C defines a free region that are elastically
deformable. An axial length of the free region, i.e., a free length
L1 is set equal to or less than 300 mm under pressureless
condition. A ratio of an axial length L2 of the main portion 7 with
respect to the free length L1 of the free region is 65% to 93%
under pressureless condition. And, an axial length L1 of the free
region is (an axial length L2 of the main portion 7+twice an axial
length L3 of the tapered portion 11+twice an axial length L4 of an
inner portion of the swaged portion 9 with respect to a swaged
position C or a length or axial length L4 of the swaged portion 9
in the free region).
[0044] For the inner surface side layer 13 and the outer surface
side layer 17, may be used butyl rubber (IIR), halogenated butyl
rubber (halogenated IIR), i.e., chlorobutyl rubber (Cl--IIR) and
bromobutyl rubber (Br--IIR), acrylonitrile-butadiene-rubber (NBR),
chloroplene rubber (CR), ethylene-propylene-diene-rubber (EPDM),
ethylene-propylene rubber (EPM), fluoro rubber (FKM),
epichlorohydrin and ethylene oxide copolymer (ECO), silicon rubber,
urethane rubber, acrylic rubber or the like, as single or blend
material. Although the outer surface side layer 17 is made of
rubber here, may be made from a shrink tube of acrylic type,
stylene type, olefin type, diolefin type, polyvinyl chloride type,
urethane type, ester type, amide type, fluorine type or the like,
and thermoplastic elastomer (TPE). And, for reinforcing filament
member or reinforcing yarn of the reinforcing layer 15, may be used
polyethylene terephthalate(PET), polyethylene naphthalate (PEN),
aramid, polyamide(PA), vinylon, rayon, or the like. Further, a
metal wire member may be also used as reinforcing filament
member.
[0045] The high-pressure resistant hose 1 is manufactured in a
following manner. First, the inner surface side layer 13, the
reinforcing layer 15 and the outer surface side layer (cover layer)
17 are laminated each other to form a multilayered lengthy body
that has uniform inner and outer diameters and wall-thickness over
its entire length, the lengthy body is cut into a pre-set length,
and a hose base body 31 is obtained (refer to FIG. 4). The
reinforcing layer 15 is formed by braiding a reinforcing yarn at a
braid angle of 48.degree. to lower than 54.degree.. In order not to
create roughness on an inner surface of the inner surface side
layer 13 by the reinforcing layer 15, a preferable wall thickness
of the inner surface side layer 13 is equal to or larger than 1.0
mm. And, in order not to create roughness on an outer surface of
the outer surface side layer 17 by the reinforcing layer 15, an
effective wall thickness of the outer surface side layer 17 is
equal to or greater than 0.9 mm.
[0046] Next, the hose base body 31 is retained by a retaining mold
(retaining member) 33 such that longitudinal opposite ends of the
hose base body 31 protrude outwardly, respectively. The retaining
mold 33 comprises half-shaped upper mold 35 and lower mold 37. The
upper and lower molds 35, 37 are formed with element recesses 39,
41 of semicircular cross-section in mating surfaces thereof,
respectively (refer to FIG. 5). The element recesses 39, 41 define
a long-slim receiving portion (cavity) 43 of circular cross-section
(more specifically, having a length equal to or generally equal to
the length L2 of the main portion 7) when the upper and lower molds
35, 37 are mated each other. A diameter of the receiving portion 43
is slightly smaller than an outer diameter of the hose base body
31. Namely, the diameter or radius of each of the element recesses
39, 41 is slightly smaller than the outer diameter or an outer
radius of the hose base body 31. Also, the element recess 39 is
formed with shallow escape slot 39a in each of opposite side edge
portions thereof, and the element recess 41 is formed with shallow
escape slot 41a in each of opposite side edge portions thereof. By
mating the upper mold 35 and the lower mold 37 together, the escape
slot 39a and the escape slot 41a are matched together to form
escape recessed portion 45 protruding outwardly on each of opposite
side portions of the receiving portion 43 (refer to FIG. 7). Each
of the escape slots 39a, 41a may be formed into a quarter circular
cross-section, a quarter oval cross-section or a quarter ellipse
cross-section, and the escape recessed portion 45 may be formed
into a semicircular cross-section (for example, cross-section of
semicircle with radius of about 1 mm), a semioval cross-section or
a semiellipse cross-section. So, when the upper mold 35 and the
lower mold 37 are mated together so as to sandwich the hose base
body 31 by the element recesses 39, 41, and thereby the hose base
body 31 is retained by the retaining mold 33, the hose base body 31
is tightly and compressively received in the receiving portion 43
that has a diameter smaller than the outer diameter of the hose
base body 31, with longitudinal opposite ends thereof protruding
outside the retaining mold 33 (refer to FIGS. 6 and 7). The hose
base body 31 is retained in the retaining mold 33 not to be allowed
to be displaced in a longitudinal direction and not to be allowed
to be expansively deformed in a diametrical direction. And,
deformation of the hose base body 31 when tightly and compressively
sandwiched by the element recesses 39, 41 is absorbed by the escape
recessed portions 45. So, it can be effectively prevented that the
hose base body 31 has a molding flash. Meanwhile, the retaining
mold 33 is retained, for example, by being attached to a retaining
equipment.
[0047] An element recess may be formed also into a semioval
cross-section or semiellipse cross-section. Such element recesses
47, 49 may be configured so as to define a receiving portion
(cavity) 51 of an oval or ellipse cross-section including a minor
axis or shortest diameter with length (D1) shorter than the outer
diameter of the hose base body 31, and a major axis or longest
diameter with length (D2) longer than the outer diameter of the
hose base body 31 when matched together. In this configuration, the
hose base body 31 is sandwiched tightly and compressively by the
element recesses 47, 49, and deformation of the hose base body 31
is absorbed in escape portions 52 at opposite end positions of the
major axis or longest diameter (refer to FIG. 8). Thereby it can be
also effectively prevented that the hose base body 31 has a molding
flash.
[0048] After the hose base body 31 is sandwiched and retained by
the retaining mold 33, a mandrel (diametrically expanding rod) 53
is inserted in each longitudinal end of the hose base body 31
protruding from the retaining mold 33 to form swaged portion 9 of
the main hose body 3. Here, prior to insertion of the mandrel 53,
it is advantageous to semi-vulcanize the hose base body 31 in order
that the reinforcing layer 15 is hard to bite in the inner surface
side layer 13. As shown in FIG. 9, the mandrel 53 integrally has a
large diameter portion 55 having an outer diameter equal to or
generally equal to an inner diameter of a to-be-formed swaged
portion 9, and a leading end guide portion 57 provided on the large
diameter portion 55. The leading end guide portion 57 includes a
leading end portion 59 having an outer diameter equal to or
generally equal to an inner diameter of the hose base body 31, and
a diametrically expanding portion 61 between the leading end
portion 59 and the large diameter portion 55 that is tapered and
diametrically contracts toward the leading end portion 59. Here, a
suitable expanding angle (a slanting angle of an outer surface with
respect to an axial direction) of the diametrically expanding
portion 61 for forming the tapered portion 11 of the main hose body
3 is 5.degree. to 25.degree.. When the expanding angle is lower
than 5.degree., the tapered portion 11 of the main hose body 3 has
a too long axial length. When the expanding angle is greater than
25.degree., insertability of the mandrel 53 (namely, workability of
inserting the mandrel 53 in the hose base body 31) is impaired.
[0049] For facilitating smooth insertion of the mandrel 53, the
mandrel 53 may be formed with a pressurizing hole therethrough that
is open at a leading end of the leading end portion 59. The mandrel
53 can be inserted in the hose base body 31 while or after a
pressurizing air is supplied in the hose base body 31 via the
pressurizing hole. Or in order to reduce sliding resistance between
the mandrel 53 and an inner surface of the hose base body 31 for
facilitating sliding of the mandrel 53 in the hose base body 31, an
insertion aid may be applied between the mandrel 53 and the hose
base body 31. For the insertion aid, water, refrigerant oil,
silicon or the like may be used.
[0050] By insertion of the mandrel 53 in the hose base body 31, a
longitudinal end portion of the hose base body 31 is diametrically
expanded, and the swaged portion 9 of large diameter and the
tapered portion 11 are formed, as shown in FIG. 10. Initially, a
braid angle of the reinforcing yarn of the reinforcing layer 15 is
in a range of 48.degree. to lower than 54.degree. in the swaged
portion 9 and the tapered portion 11. However, due to diametrical
expansion, the braid angle of the reinforcing yarn of the
reinforcing layer 15 becomes in a range of over 57.degree. to
68.degree. on the swaged portion 9, and in a range of over about
55.degree. to 61.degree. on the tapered portion 11 (more
specifically, on an axial center of the tapered portion 11).
Meanwhile, in the swaged portion 9, the braid angle of the
reinforcing yarn of the reinforcing layer 15 may be set in a range
of 60.degree. to 68.degree.. And, in the tapered portion 11, the
braid angle of the reinforcing yarn of the reinforcing layer 15
(the braid angle on an axial center of the tapered portion 11) may
be set in a range of over about 55.degree. to 60.degree..
[0051] When the mandrels 53 are inserted in the hose base body 31,
the hose base body 31 is heated and vulcanized while being retained
by the retaining mold 33. Then, the retaining mold 33 and the
mandrels 53 are removed, and the main hose body 3 can be obtained
as shown in FIG. 11. On the swaged portion 9 of thus manufactured
main hose body 3, the joint devices 5 are mounted to obtain the
high-pressure resistant hose 1 as shown in FIG. 1. A length change
rate (elongation rate) under exerted pressure of the high-pressure
resistant hose 1 is set in a range of -5% to 10%.
[0052] Then examples according to the present invention will be
described.
[0053] As shown in Table 1, with respect to the high-pressure
resistant hose 1, examples of high-pressure resistant hoses No. 1
to No. 6 and comparison examples of high-pressure resistant hoses
No. 1 to No. 4 are produced, respectively, and each is measured and
evaluated with respect to length change rate under exerted pressure
(%), bursting pressure at room temperature (RT) (MPa), and
durability under repeated pressures at high temperature. In the
examples of the high-pressure resistant hoses No. 1 to No. 5 and
the comparison examples of the high-pressure resistant hoses No. 1
to No. 4, respectively, the joint devices 5 of the same
configuration are employed. In the example No. 6 of the
high-pressure resistant hose, a joint device with the same
construction, but of a slightly larger diameter is used.
[0054] The length change rate under exerted pressure is a value
measured when a pressure is exerted at 3.5 MPa for 1 minutes with
regard to the high-pressure resistant hose including a main portion
with an inner diameter of 9.0 mm, and a value measured when a
pressure is exerted at 1.1 MPa for 1 minutes with regard to the
high-pressure resistant hose including a main portion with an inner
diameter of 12.0 mm. The busting pressure at RT is a pressure at
which the high-pressure resistant hose bursts when water pressure
is exerted in the high-pressure resistant hose at room temperature
while being increased by 160 MPa/minutes. The durability under
repeated pressures at high temperature is indicated by durability
when the high-pressure resistant hose is bent at 90.degree. into
L-shape on a longitudinal center thereof, securely fixed at
longitudinal opposite end portions, one longitudinal end portion is
closed and an oil pressure is applied repeatedly in the other
longitudinal end portion. Here, an oil pressure of 100.degree. C.,
3.5 MPa is supplied repeatedly at pressurizing speed of 35 cpm.
[0055] In the line "No. of yarns" of the reinforcing layer of each
of the examples and comparison examples in Table 1, "2 parallel
yarns.times.24 carriers" means that two parallel reinforcing yarns
are braided on a 24 carrier machine.
[0056] In Table 1, in the line "Length" (axial length, refer to L3)
of "Tapered portion", figures "20", "12" and "10" indicate that the
examples and the comparison examples have tapered portions with
length of 10 mm, 6 mm and 5 mm on opposite end portions thereof,
respectively. This also applies to the line "Length" of "Swaged
portion", and the examples and the comparison examples have swaged
portions with length of 6 mm, 5 mm and 4 mm on opposite end
portions thereof, respectively. And, "Length" of "Swaged portion"
means a length of the swaged portion in a free region of a main
hose body (refer to L4).
[0057] With regard to "Bursting pressure at RT", a target value is
20 MPa or more for the high-pressure resistant hose including the
main portion with the inner diameter of 9 mm, and the target value
is 10 MPa or more for the high-pressure resistant hose including
the main portion with the inner diameter of 12 mm. TABLE-US-00002
TABLE 1 Demension under pressureless condition Examples 1 2 3 4 5 6
Main Dimension Inner diameter (mm) 9.0 9.0 9.0 9.0 9.0 12.0 portion
Outer diameter (mm) 16.0 16.0 16.0 16.0 16.0 18.0 Length (mm) 60
100 100 250 278 200 Inner Material Cl-IIR Cl-IIR Cl-IIR Cl-IIR
Cl-IIR Cl-IIR surface Wall thickness (mm) 2.0 2.0 2.0 2.0 2.0 1.6
layer Reinforcing Material PET PET PET PET PET PET layer No. of
denier 3000de 3000de 3000de 3000de 3000de 3000de No. of yarns 2 2 2
2 2 2 parallel parallel parallel parallel parallel parallel yarns
.times. yarns .times. yarns .times. yarns .times. yarns .times.
yarns .times. 24 24 24 24 24 24 carriers carriers carriers carriers
carriers carriers Braid angle (.degree.) 49 49 52 49 49 52 Outer
Material EPDM EPDM EPDM EPDM EPDM EPDM surface layer Wall thickness
(mm) 1.0 1.0 1.0 1.0 1.0 1.0 Tapered Dimension Length (mm) 20 20 20
20 12 20 portion Reinforcing Braid angle (.degree.) 58 58 60 58 58
57 layer Swaged Dimension Inner diameter (mm) 12.0 12.0 12.0 12.0
12.0 15.0 portion Outer diameter (mm) 17.5 17.5 17.5 17.5 17.5 20.5
Length (mm) 12 12 12 12 10 12 Reinforcing Braid angle (.degree.) 66
66 67 68 68 61 layer Length of main hose body (free length) under
100 130 136 272 285 228 exerted pressure (mm) Initial length of
main hose body (free length) 92 132 132 282 300 232 (mm) Good Good
Good Good Good Good Length of main portion/initial length of main
65 76 76 89 93 86 hose body (%) Length change ratio under exerted
pressure (%) 8.7 -1.5 3.0 -3.5 -5.0 -1.7 Good Good Good Good Good
Good Bursting pressure at RT (MPa) 23.2 23.1 25.0 22.8 22.7 14.0
Good Good Good Good Good Good Durability under repeated pressures
at high 100,000 100,000 100,000 100,000 100,000 100,000 temperature
cycles cycles cycles cycles cycles cycles No No No No No No
disruption disruption disruption disruption disruption disruption
Comparison examples 1 2 3 4 Main Dimension Inner diameter (mm) 9.0
9.0 9.0 9.0 portion Outer diameter (mm) 16.0 16.0 16.0 16.0 Length
(mm) 100 100 50 282 Inner Material Cl-IIR Cl-IIR Cl-IIR Cl-IIR
surface Wall thickness (mm) 2.0 2.0 2.0 2.0 layer Reinforcing
Material PET PET PET PET layer No. of denier 3000de 3000de 3000de
3000de No. of yarns 2 2 2 2 parallel parallel parallel parallel
yarns .times. yarns .times. yarns .times. yarns .times. 24 24 24 24
carriers carriers carriers carriers Braid angle (.degree.) 47 54 49
49 Outer Material EPDM EPDM EPDM EPDM surface layer Wall thickness
(mm) 1.0 1.0 1.0 1.0 Tapered Dimension Length (mm) 20 -- 20 10
portion Reinforcing Braid angle (.degree.) 58 -- 58 60 layer Swaged
Dimension Inner diameter (mm) 12.0 12.0 12.0 12.0 portion Outer
diameter (mm) 17.5 Unable to be 17.5 17.5 Length (mm) 12
diametrically 12 8 expanded Reinforcing Braid angle (.degree.) 66
69 or less 68 67 layer Length of main hose body (free length) under
124 91 284 exerted pressure (mm) Initial length of main hose body
(free length) 132 82 300 (mm) Good Good Good Length of main
portion/initial length of main 76 61 94 hose body (%) Length change
ratio under exerted pressure (%) -6.1 10.4 -5.3 Inferior Inferior
Inferior Bursting pressure at RT (MPa) 21.0 23.5 23.0 Good Good
Good Durability under repeated pressures at high 100,000 100,000
100,000 temperature cycles cycles cycles No No No disruption
disruption disruption
[0058] As understood from Table 1, in the comparison example 1
including the reinforcing layer of braid angle 47.degree. on the
main portion, the main portion contracts largely in a longitudinal
direction under exerted pressure, and the length change ratio under
exerted pressure of an entire free length or free length is -6.1%,
a minus value, and a large absolute value. In the comparison
example 3 where the ratio of the length (an axial length, refer to
L2) of the main portion with respect to the entire free length or
free length (initial length of the main hose body, refer to L1)
under pressureless condition is as small as 61%, a portion except
for the main portion too much affects the length change ratio of
the entire free length under exerted pressure, and therefore the
length change ratio under exerted pressure is large, 10.4%. In the
comparison example 2 including the reinforcing layer of braid angle
of 54.degree. on the main portion, buckling is caused on the hose
base body at the time of formation of the swaged portion, and the
mandrel cannot be properly inserted in the hose base body. In the
comparison example 4, where the ratio of the length of the main
portion with respect to the entire free length or free length
(initial length of the main hose body) under pressureless condition
is large, about 94%, the main portion too much affects the length
change ratio of the entire free length under exerted pressure, and
therefore the length change ratio under exerted pressure is -5.3%,
a minus value, and a large absolute value large minus value.
[0059] On the contrary, in each of the examples No. 1 to No. 6
including the reinforcing layers of the braid angles 49.degree. to
52.degree. on the main portions 7, 61.degree. to 68.degree. on the
swaged portions 9, and 57.degree. to 60.degree. on the tapered
portions 11, respectively, the ratio of the length L2 of the main
portion 7 with respect to the entire free length or free length
(initial length of the main hose body) L1 under pressureless
condition is good, 65% to 93%, and the length change ratio of the
entire free length under exerted pressure is also good, -5.0% to
8.7%. And there is no disruption in the examples No. 1 to No. 6
even after 100,000 cycles of repeated pressures at high
temperature. And, the high-pressure resistant hose including the
main portion 7 with the inner diameter of 9.0 mm has a high
bursting pressure of 22.8 MPa at minimum, and the high-pressure
resistant hose including the main portion 7 with the inner diameter
of 12 mm has a sufficient bursting pressure of 14.0 MPa.
[0060] The high-pressure resistant hose according to the present
invention is, for example, arranged in a narrow piping space such
as an engine room, and is used for conveying a high-pressure
fluid.
[0061] And, according to the method for producing the high-pressure
resistant hose of the present invention, it is possible to easily
produce the high-pressure resistant hose, for example, to be
arranged in the narrow piping space such as an engine room, and to
be used for conveying a high-pressure fluid.
* * * * *