U.S. patent application number 13/408043 was filed with the patent office on 2012-06-21 for tape-shaped molding and belt for ball chain.
Invention is credited to Katsuya Iida, Yuji Kokuno, Nobuyuki MASUMURA, Hidekazu Michioka, Seiichi Ohira, Akira Tochigi, Kazuki Tomita.
Application Number | 20120156468 13/408043 |
Document ID | / |
Family ID | 28456251 |
Filed Date | 2012-06-21 |
United States Patent
Application |
20120156468 |
Kind Code |
A1 |
MASUMURA; Nobuyuki ; et
al. |
June 21, 2012 |
TAPE-SHAPED MOLDING AND BELT FOR BALL CHAIN
Abstract
A tape-shaped product and a belt for a ball chain are provided.
A tape-shaped product of synthetic resin includes a tape of a
thermoplastic resin, and a preliminarily stretched fibrous member
of a thermoplastic resin contained therein along longitudinally
parallel edges or in proximity thereto of the tape. A belt for a
ball chain, includes a tape-shaped product of synthetic resin
formed by injection molding, together with a fibrous member as an
insert of a resin of the same kind as that of the fibrous member so
that the fibrous member is disposed along the longitudinal edges or
in proximity thereto, ball-insetting holes are disposed at equal
intervals, and ball-retaining projections are disposed around the
holes.
Inventors: |
MASUMURA; Nobuyuki;
(Tochigi-Ken, JP) ; Tomita; Kazuki; (Tochigi-Ken,
JP) ; Tochigi; Akira; (Tochigi-Ken, JP) ;
Kokuno; Yuji; (Tochigi-Ken, JP) ; Ohira; Seiichi;
(Tochigi-Ken, JP) ; Michioka; Hidekazu; (Tokyo,
JP) ; Iida; Katsuya; (Yamanashi-Ken, JP) |
Family ID: |
28456251 |
Appl. No.: |
13/408043 |
Filed: |
February 29, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10508788 |
Sep 23, 2004 |
|
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PCT/JP03/03684 |
Mar 26, 2003 |
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13408043 |
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Current U.S.
Class: |
428/297.4 ;
264/257 |
Current CPC
Class: |
F16C 33/3825 20130101;
B29C 45/36 20130101; B29K 2995/0049 20130101; F16C 33/506 20130101;
B29K 2101/12 20130101; F16C 2208/20 20130101; B29C 45/0001
20130101; B29C 2045/363 20130101; B29K 2995/0077 20130101; B29L
2029/00 20130101; F16C 29/0635 20130101; F16C 43/06 20130101; F16C
33/3831 20130101; F16H 25/2233 20130101; F16C 2220/04 20130101;
B29C 45/14549 20130101; Y10T 428/24994 20150401 |
Class at
Publication: |
428/297.4 ;
264/257 |
International
Class: |
B32B 27/04 20060101
B32B027/04; B29C 45/14 20060101 B29C045/14 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 26, 2002 |
JP |
85118/2002 |
Mar 24, 2003 |
JP |
80108/2003 |
Claims
1. A tape-shaped product of synthetic resin, comprising: a tape of
a synthetic resin, and a stretch-oriented fibrous member of a
thermoplastic resin contained therein along longitudinally parallel
edges or in proximity thereto of the tape; wherein said
thermoplastic resin forming the fibrous member and said synthetic
resin forming the tape comprise substantially identical resins.
2. A tape-shaped product of synthetic resin according to claim 1,
wherein the fibrous member is in the form of a monofilament.
3. A tape-shaped product of synthetic resin according to claim 1,
having a longitudinal tensile strength of at least 250 MPa and a
thermal shrinkability of at most 1%.
4-7. (canceled)
8. A method of producing a belt for ball chain, comprising:
setting, in a mold, balls for molding each having a diameter
slightly larger than balls to be retained in a resultant shaped
product so as to be aligned in a straight line along a central
portion of the resultant shaped product, and a stretch-oriented
fibrous member comprising a thermoplastic resin so as to be
contained along longitudinally parallel edges or in proximity
thereof of the resultant shaped product, injection-molding a
moldable synthetic resin comprising a substantially identical resin
as the thermoplastic resin forming the stretch-oriented fibrous
member to form a tape portion and a retaining portion integrally,
and then removing the balls for molding to leave holes for
retaining balls of the ball chain, thereby to form a belt for ball
chain which comprises: (i) a tape-shaped product of synthetic
resin, comprising: a tape of a synthetic resin, and a
stretch-oriented fibrous member of a thermoplastic resin contained
therein along longitudinally parallel edges or in proximity thereto
of the tape; wherein said thermoplastic resin forming the fibrous
member and said synthetic resin forming the tape comprise
substantially identical resins, and (ii) the holes for retaining
balls of the ball chain along the central portion of the
tape-shaped product.
9. A method of producing a belt for ball chain according to claim
8, wherein the fibrous member is in a form of a monofilament.
10. A tape-shaped product of synthetic resin according to claim 2,
having a longitudinal tensile strength of at least 250 MPa and a
thermal shrinkability of at most 1%.
11. A tape-shaped product of synthetic resin according to claim 1,
wherein said thermoplastic resin forming fibrous member and said
thermoplastic resin forming the stretch-oriented fibrous member
comprise identical resins or include identical resins as principle
components.
12. A method of producing a belt for ball chain according to claim
8, wherein said thermoplastic resin forming the fibrous member and
said thermoplastic resin forming the stretch-oriented fibrous
member comprise identical resins or include identical resins as
principle components.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional of U.S. application Ser.
No. 10/508,788, filed Sep. 23, 2004, which is a 371 national stage
application of PCT/JP03/03684, filed Mar. 26, 2003, the entireties
of which are incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to a tape-shaped product and a
belt for a ball chain used in a guide device for linear motion on a
track utilizing rolling of a plurality of rolling members, such as
balls or rollers (hereinafter representatively referred to as
"ball(s)").
BACKGROUND ART
[0003] Hitherto, various tape-shaped products of thermal resins are
known, but almost no proposals have been made regarding a
tape-shaped product suitable for forming a belt including a planar
tape portion provided with a multiplicity of holes for retaining
another object thereat. As an example of such a belt including a
planar tape portion provided with a multiplicity of holes for
holding another object thereat, there is an endless belt retaining
balls rollably thereon for a guide device for linear motion on a
track. As disclosed in Japanese Laid-Open Patent Application (JP-A)
5-52217, such a belt includes ball-retaining portions intervening a
plurality of balls arranged with prescribed intervals in a row, and
a flexible connecting member for connection between respective
ball-retaining portions.
[0004] For production of a belt for a ball chain (hereinafter
sometimes referred as a ball chain belt), there are known a method
of forming prescribed ball-retaining holes in an extruded tape, and
a method of direct injection molding without such a tape product.
An example of the former method is disclosed in JP-A 2001-74048
wherein an elongated flat tape product (i.e., a belt member) is
preliminarily formed by extrusion and is cut in a prescribed length
to form a row of holes for loosely retaining balls, and spacer
portions are formed between adjacent retaining holes for retaining
balls while using the balls as inserts. In a case of forming a tape
product (a belt member) by extrusion of a synthetic resin and then
forming ball-retaining holes for retaining balls rollably, it is
difficult to obtain a strength sufficient for using this product as
an endless belt subject to sliding movement. Further, adhesion
between spacer portions formed by injection molding and the belt
member is insufficient so as to cause dropping-off of the spacer
portions. For this reason, for a purpose of ensuring a tensile
strength and a flexural strength of the belt member, JP-A
2001-74048 also discloses a method of using two extruders for
extruding a resin functioning as a reinforcing material and a resin
coating the reinforcing material to form a tape portion through a
common die, and an extrusion forming method of embedding
reinforcing members, such as glass fiber, carbon fiber or ceramic
fiber along parallel longitudinal edges of a flat band-shaped belt.
However, the above-mentioned method of co-extruding two types of
resins for forming a reinforcing member cannot provide a sufficient
strength, and if a large ratio of stretching is applied thereto for
providing an increased strength, thermal shrinkability becomes
larger, so that this product is not suitable for such use as an
endless belt for retaining balls rollably in a linear motion guide
device. On the other hand, the fiber, such as glass fiber, carbon
fiber or ceramic fiber, of a material different from belt-forming
material cannot be sufficiently strongly bonded with the
belt-forming material, whereby these materials are liable to form a
gap therebetween due to various loads during use, and strength is
rapidly lowered if this gap occurs, thus involving a problem
regarding durability.
[0005] Further, in another method of producing a ball chain belt as
disclosed in, e.g., JP-A 11-247856, ball frames having a diameter
larger than that of balls used for the ball chain are aligned in
projections at prescribed intervals in a metal mold for injection
molding of synthetic resin, and a synthetic resin is injected into
the metal mold to form a connecting belt with the ball frames
aligned therein, followed by removal of the connecting belt from
the metal mold and pushing-in of balls into the ball frames of the
molded product so as to rollably retain the balls therein.
According to this method, it is very difficult to develop a
sufficient size accuracy, and even if a sufficient accuracy can be
attained, metal mold production costs become very expensive.
Further, the removal of this product from the mold is difficult,
and a proportion of defectives is liable to be higher due to
occurrence of fins around the holes.
[0006] In another method as disclosed in, e.g., JP-A 5-196037, a
plurality of ball pieces disposed between balls and a connecting
band, connecting the ball pieces and provided with ball holes for
receiving the balls, are integrally formed by injection molding.
During the injection method, resins injected out of respective
gates are joined together at an intermediate point between the
gates to form a weld, of which a strength is liable to be
lowered.
[0007] As described above, there has not been provided a
tape-shaped product suitable for forming a belt including a planar
tape portion provided with a multiplicity of holes for retaining
another object thereat. Further, production of the belt members
according to the above-mentioned methods is complicated, and it is
difficult to attain a desired strength being exhibited by the
products.
SUMMARY OF THE INVENTION
[0008] The inventors have studied for a purpose of providing a
tape-shaped product suitable for forming a belt including a planar
tape portion provided with a multiplicity of holes for retaining
another object thereat and having a large tensile strength, and a
shaped product having a large tensile strength as a belt chain belt
having a large tensile strength for rollably retaining balls
aligned in a row, to arrive at the present invention.
[0009] An object of the present invention is to provide a
tape-shaped product suitable for forming a belt including a planar
tape portion provided with a multiplicity of holes, or a belt for
retaining another object at such holes, or a belt for a ball chain
(i.e., a ball chain belt) exhibiting excellent ball-retaining power
and durability.
[0010] The present invention relates to a tape-shaped product of
thermoplastic resin which contains a preliminarily stretched
fibrous member of thermoplastic resin (hereinafter referred to as
"stretched fibrous member") along longitudinally parallel edges or
in proximity thereto. It is preferred that the stretched fibrous
member comprises a resin exhibiting good adhesion, and being
moldable together, with the resin forming the tape, and that the
tape-shaped product has a longitudinal tensile strength of at least
250 MPa and a thermal shrinkability of at most 1%, more preferably
a longitudinal tensile strength of at least 300 MPa and a thermal
shrinkability of at most 0.5%
[0011] The present invention further relates to a tape-shaped
product of synthetic resin formed by injection molding resin
together with a stretched fibrous member, of a thermoplastic resin
exhibiting good adhesion, with the stretched fibrous member, and
provided with the stretched fibrous member contained therein at
positions along longitudinally parallel edges or in proximity
thereto, ball-insetting holes disposed at equal intervals in a
straight line, and ball-retaining members (which need not hold the
balls but are sufficient if they prevent direct contact of mutually
adjacent balls). In the ball chain belt of the present invention,
the stretched fibrous member may comprise a synthetic resin
exhibiting good adhesion, and moldability together, with the resin
forming the belt, and the belt may exhibit a tensile strength of at
least 100 MPa, a ball-retaining power of at least 30 MPa when balls
are inset in the ball-insetting holes, and a thermal shrinkability
of at most 1%. It is preferred that the tensile strength is at
least 150 MPa, the ball-retaining power is at least 45 MPa when the
balls are inset in the ball-insetting holes, and the thermal
shrinkability is at most 0.5%. In this instance, it is sufficient
that the stretched fibrous member is disposed at positions outside
the insetting holes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a perspective view showing a tape-shaped product
of the invention.
[0013] FIGS. 2A-2C show a ball chain belt of the invention,
including a planar view (FIG. 2A), a longitudinal sectional view
(FIG. 2B) and a lateral side view (FIG. 2C).
[0014] FIGS. 3A and 3B show states of stretched fibrous members
being set in a mold for forming a tape-shaped product of the
invention, including a longitudinal sectional view (FIG. 3A), and a
lateral sectional view (FIG. 3B).
[0015] FIG. 4 is a perspective view of a comparative tape-shaped
product not containing stretched fibrous members.
[0016] FIG. 5 shows a comparative composite tape-shaped product
containing co-extruded cores.
[0017] FIG. 6 is a view showing a state of forming ball-insetting
holes in a tape-shaped product of the invention.
[0018] FIG. 7 is a view showing a state wherein stretched fibrous
members and balls are set in a mold for forming a ball chain belt
of the invention.
[0019] FIGS. 8A-8C show a comparative ball chain belt free of
stretched fibrous members, including a planar view (FIG. 8A), a
longitudinal side view (FIG. 8B), and a lateral side view (FIG.
8C).
[0020] FIGS. 9A-9C show a comparative ball chain belt free of
stretched fibrous members, including a planar view (FIG. 9A), a
longitudinal side view (FIG. 9B) and a lateral side view (FIG.
9C).
[0021] FIG. 10 is a view showing a state of forming ball-insetting
holes in a comparative tape-shaped product free of stretched
fibrous members.
[0022] FIG. 11 is a view showing a state wherein rollers are set in
a mold for forming a roller-type ball chain belt of the
invention.
[0023] FIGS. 12A-12C show views of a roller-type ball chain belt of
the invention, including a planar view (FIG. 12A), a longitudinal
side view (FIG. 12B), and a lateral side view (FIG. 12C).
[0024] FIG. 13 is a perspective view of a linear motion guide
device in which a ball chain according to the invention has been
incorporated.
[0025] FIG. 14 is a perspective view of a linear motion guide
device in which a roller-type ball chain according to the invention
has been incorporated.
[0026] FIG. 15 is a sectional view of a ball screw in which a ball
chain according to the invention has been incorporated.
[0027] Respective symbols correspond to respective component
members as follows. [0028] 1: stretched fibrous member, 2: tape
member, 3: ball-retaining hole, 4: ball-retaining member, 5: ball
for molding, 6: core, 7: ball-insetting state, 8: mold, 9:
roller-retaining hole, 10: roller-retaining member, 11: linear
motion guide device, 12: tracking rail, 13: movable block body, 14:
ball chain, 15: linear motion guide device, 16: tracking rail, 17:
movable block body, 18: roller-type ball chain, 19: ball screw, 20:
screw shaft, 21: nut, 22: return pipe, 23: ball chain (ball belt
and balls)
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] A tape-shaped product according to a first embodiment of the
invention is shown in FIG. 1, and comprises stretched fibrous
members 1 and injected resin 2. The stretched fibrous members 1 are
set in advance in a mold so as to be contained in a resultant
molded product along longitudinally parallel edges or positions
proximate thereto of the molded product, and a resin moldable
together with and having good adhesion with the stretched fibrous
members is molded by injection to form tape-shaped member
(injection-molded resin member) 2 integral with the stretched
fibrous members 1. As a result, it is possible to obtain a resinous
tape-shaped product having a longitudinal tensile strength of at
least 250 MPa and a thermal shrinkability of at most 1%; preferably
a longitudinal tensile strength of at least 300 MPa and a thermal
shrinkability of at most 0.5%. Incidentally, thermal
shrinkabilities are based on values measured after allowing samples
to stand for 24 hours under no tension at 40.degree. C. (dry).
[0030] A ball chain belt according to a second embodiment of the
invention is shown in FIGS. 2A-2C including a planar view (FIG.
2A), a longitudinal side view (FIG. 2B), and a lateral side view
(FIG. 2C), and comprises stretched fibrous members 1 along
longitudinally parallel edges or at positions proximate thereto of
a tape-shaped product, a tape-shaped member (of injection-molded
resin) 2, a multiplicity of ball-insetting holes 3 disposed at
equal intervals aligned in a central portion of the tape-shaped
member 2, and ball-retaining members 4 each disposed between
adjacent ball-insetting holes 3. In this instance, it is sufficient
that the stretched fibrous members 1 are disposed at positions
outside the ball-insetting holes 3. Dashed lines 7 in FIG. 2B each
represents a state of a ball being inset in position.
[0031] A ball chain belt of the present invention as described
above may be produced in the following manner. That is, in a
tape-shaped product containing stretched fibrous members (FIG. 1)
produced in the above-described manner, holes 3 having a diameter
slightly larger than that of a ball (or roller) retained therein
are formed at equal intervals by perforation as shown in FIG. 6,
balls for molding are inset in the holes 3, and ball-retaining
members 4 are formed in projection by injection molding around the
holes 3. Alternatively, without such a tape-shaped product, balls 5
having a diameter slightly larger than that of a ball to be
retained and stretched fibrous members 1 are disposed in a mold as
shown in FIG. 7, and a prescribed resin is injection-molded to
integrally form the tape member 2 and the retaining members 4.
Thus, a shaped product containing the stretched fibrous members
along longitudinally parallel edges, or at positions proximate
thereto and fixing a mid portion of the balls, is formed, and then
the balls for molding are removed to provide a ball chain belt. By
using the ball chain belt, prescribed balls to be retained are
inset at respective holes to provide a ball chain rollably
retaining the balls.
[0032] Herein, preliminarily stretched fibrous member(s) refers to
a fibrous member including oriented molecular chains obtained by
stretching a yet-unstretched fibrous member formed by fiber
spinning. This stretching may be performed by any method capable of
providing an enhanced orientation of the fibrous member. For
example, it is possible to adopt a method of subjecting such a
yet-unstretched fibrous member continuously to a stretching step.
Alternatively, such a yet-unstretched fibrous member may be later
subjected to a separate stretching step. The stretching may be
effected in a single step or multiple steps including two or more
steps, and may also include a step of heat-treatment, and the like.
A stretching medium may be gas, liquid or a hot plate and need not
be restricted particularly. Further, it is also possible to adopt a
direct spinning-stretching method wherein a resin ejected out of a
spinning nozzle is subjected to drafting. A preliminarily stretched
fibrous member of thermoplastic resin may comprise stretched fiber
having a tensile strength of at least 300 MPa, preferably 450-1000
MPa and may be in the form of a mono-filament or multi-filaments.
The stretched fibrous member may comprise composite-structured
fiber (e.g., core/sheath structure), combined yarn fiber, twisted
yarn fiber or non-circular section fiber, or any other form so long
as it can retain an adhesion with the injected resin to exhibit a
sufficient strength. As a preliminarily stretched fibrous member of
thermoplastic resin, it is preferred to use a mono-filament (in a
sense of including a core-sheath type composite yarn) of a resin of
the same kind as the resin for injection molding.
[0033] These resins moldable together and exhibiting good adhesion
with each other need not be entirely identical but may be those
including principal components of identical resins, may be resins
of a same type or family, or may include a stretched fibrous member
of which a surface is chemically or physically treated to exhibit
such an adhesiveness as not to cause a practically easy separation.
The resin for injection molding is not particularly restricted so
long as it allows injection molding, but may comprise various
elastomers (e.g., polyester-type, nylon-type, polyolefin-type,
acryl-type, fluorine-containing resin-type), or various synthetic
resins (e.g., polyester-type, nylon-type, polyolefin-type,
acryl-type, fluorine-containing resin-type), and the like.
[0034] Specific combinations of the stretched fibrous member and
the injection molding resin may include a combination of identical
resins, and also combinations of a PVDF/PMMA core/sheath composite
yarn and acryl-type elastomer, polyester-type elastomer, PBT-type
elastomer, or the like; a PVDF/PMMA mixture fiber and the
above-mentioned elastomer; and PMMA-impregnated UHMWPE fiber string
and PMMA, and the like.
[0035] In the tape-shaped product formed from the stretched fibrous
member and a resin moldable together and exhibiting good adhesion
therewith through injection molding, the stretched fibrous member
may desirably occupy a ratio of 10-70%, preferably 20-60%, of a
sectional area perpendicular to a longitudinal direction. The ratio
can vary depending on a size, desired strength, and the like, of
the tape-shaped product.
[0036] In the tape-shaped product of the present invention, the
molded resin portion other than the fibrous members has an
orientation which is lower than that of the fibrous members and in
such a degree as to provide a thermal shrinkability of the
tape-shaped product of preferably at most 1%, more preferably at
most 0.5%.
[0037] The tape-shaped product of the present invention may have a
shape of section perpendicular to the longitudinal direction, which
shape is not restricted to a quadrangle or rectangle having four
sides, but may also be a trigon, a polygon, each capable of
including one or more curved sides, or further an ellipse or a
shape formed by dividing an ellipse into two halves.
[0038] The tape-shaped product of the present invention may have a
section as described above exhibiting a ratio of a maximum
thickness to a width in a range of 1:50-1:1, preferably 1:20-1:1,
further preferably 1:15-1:2. It is particularly preferred that the
tape-shaped product has a sectional shape of a rectangle exhibiting
a ratio of a maximum thickness to a width of 1:15-1:2.
[0039] A ball chain obtained by insetting balls in a tape-shaped
product of the present invention may preferably be used as a
ball-connecting member in a linear motion guide device equipped
with a ball-retaining endless circulation path, and in a ball screw
device as disclosed in, e.g., JP-A 11-37246.
EXAMPLES
[0040] Hereinbelow, the present invention will be described more
specifically based on Examples and Comparative Examples.
Incidentally, measurement conditions for thermal shrinkability,
tensile strength and elongation in the following Examples and
Comparative Examples are as follows. (Measurement method and
measurement conditions)
(1) Thermal Shrinkability
[0041] Measured at a temperature of 40.degree. C. (dry) for a time
of 24 hours.
(2) Tensile Strength and Elongation Measured by subjecting a test
piece of 50 mm in length to a tensile speed of 50 mm/min. by using
Tension UCT=100Model (made by Orientec K.K.) in an environment at a
temperature of 23.degree. C.
(3) Ball-Retaining Strength of Ball Chain Belt
[0042] A ball is inset in a third hole from an end of a ball chain
belt, which is then subjected to measurement in the same manner as
that for tensile strength.
[0043] A ball chain belt is provided with circular holes and
therefore has different sectional areas at respective positions,
and breakage occurs at a portion of a smallest sectional area. The
ball-retaining strength is calculated based on the smallest
sectional area.
[0044] Physical properties of products obtained in Examples and
Comparative Examples are inclusively shown in Tables 1 and 2.
Example 1
[0045] A polyester elastomer of MFR=10 was spun at a resin
temperature of 240.degree. C. through a 50 mm-dia. extruder to form
an unstreched filament. The unstretched filament was stretched at
5.8 times in a hot air oven of 150.degree. C. and relaxed by 10% in
a hot air oven at 180.degree. C. to obtain a stretched filament of
200 .mu.m. The stretched filament exhibited a tensile strength of
470 MPa and an elongation of 86%.
[0046] Then, the stretched filament was set in a mold for injection
molding as shown in FIGS. 3A and 3B, and an identical resin as the
stretched filament was injected at 280.degree. C. in the mold to
form a tape-shaped product as shown in FIG. 1 having a width of
0.65 mm and a thickness of 0.24 mm. The stretched filament occupied
40% of a sectional area perpendicular to a longitudinal direction.
As is understood from the physical properties shown in Table 1, the
tape-shaped product exhibited a high tensile strength, a low
thermal shrinkability, and thus a good size accuracy.
Comparative Example 1
Comparative Example 1-(1)
[0047] An identical resin as in Example 1 was used in the same
manner as in Example 1 except for not setting a stretched filament
to form a tape-shaped product as shown in FIG. 4 having a width of
0.65 mm and a thickness of 0.24 mm. This product exhibited a much
lower tensile strength of 61 MPa than the tape-shaped product of
Example 1.
Comparative Example 1-(2)
[0048] A polyester elastomer of MFR=10 was spun at a resin
temperature of 240.degree. C. through a 50 mm-dia. extruder to form
an unstretched filament. Then, similarly as in Example 1, the
unstretched filament was set in a mold for injection molding as
shown in FIG. 3, and an identical resin as the unstretched filament
was injected into the mold for injection molding, to form a
tape-shaped product as shown in FIG. 1 having a width of 0.65 mm
and a thickness of 0.24 mm. This product exhibited a much lower
tensile strength of 65 MPa than the tape-shaped product of Example
1.
[0049] From these Comparative Examples, effectiveness of disposing
stretched filaments in Example 1 is understood.
Comparative Example 2
[0050] A tape-shaped product not containing stretched fibrous
members unlike the tape-shaped product of Example 1 was produced by
extrusion.
<2-(1)>
[0051] A tape-shaped product as shown in FIG. 4 was obtained by
using a 50 mm-dia. extruder instead of injection molding as in
Example 1.
<2-(2)>
[0052] A tape-shaped product was formed by extrusion in the same
manner as in the above 2-(1), followed successively by stretching
at 5.8 times in a hot air oven at 150.degree. C. and relaxation by
10% in a in a hot air oven at 180.degree. C. to obtain a
tape-shaped product as shown in FIG. 4.
<2-(3)>
[0053] A tape-shaped product was formed by extrusion in the same
manner as in the above 2-(1), followed successively by stretching
at 6.25 times in a hot air oven at 180.degree. C. and relaxation by
30% in a hot air oven at 320.degree. C. to obtain a tape-shaped
product as shown in FIG. 4.
<2-(4)>
[0054] A tape-shaped product as shown in FIG. 4 was obtained in the
same manner as in the above 2-(2) except that a stretching ratio
was changed to 6.9 times.
[0055] The tape-shaped products of Comparative Examples 2-(1) to
2-(4) not containing stretched filaments but obtained through
extrusion exhibited lower tensile strengths. These extruded
products when further subjected to stretching exhibited a large
tensile strength but were accompanied with an undesirably larger
thermal shrinkability than tape-shaped products at a larger
stretching ratio. Further, in any case, these products failed to
exhibit a sufficient strength compared with the tape-shaped product
of Example 1.
Example 2
[0056] A core/sheath-type composite yarn (core/sheath ratio=80/20%
by volume) with a core of polyester elastomer of MFR=10 and a
sheath of polyester elastomer of MFR=17 was spun at a resin
temperature of 240.degree. C. to form an unstretched filament. The
unstretched filament was stretched at 5.8 times in a hot air oven
of 180.degree. C. to form a stretched filament of 200 .mu.m. The
stretched filament exhibited a tensile strength of 437 MPa and an
elongation of 71%. By using the stretched filament and a polyester
elastomer of MFR=10, a tape-shaped product as shown in FIG. 1
having a width of 0.65 mm and a thickness of 0.24 mm was obtained
in the same manner as in Example 1. In this tape-shaped product,
the stretched filament occupied 40% of a sectional area
perpendicular to a longitudinal direction. The tape-shaped product
also exhibited excellent physical properties similarly as the
tape-shaped product of Example 1.
Comparative Example 3
[0057] A tape-shaped product (as shown in FIG. 5) having cores 6
corresponding to the stretched filament in Example 2 was produced
by co-extrusion.
<3-(1)>
[0058] Instead of the injection molding in Example 2, a polyester
elastomer of MFR=10 and a polyester elastomer of MFR=17 were
co-extended so that the polyester elastomer of MFR=10 formed 0.2
mm-dia. cores along both edges of a shaped tape, thus producing a
tape-shaped product (width=0.65 mm, thickness=0.24 mm, core
diameter=0.2 mm) as shown in FIG. 5 containing cores 6.
<3-(2)>
[0059] A core-containing tape-shaped product was formed by
co-extrusion in the same manner as in the above 3-(1), and then
stretched at 5.8 times in a hot air oven at 150.degree. C. and
further relaxed by 10% in a hot air oven at 180.degree. C. to
obtain a core-containing tape-shaped product (width=0.65 mm,
thickness=0.24 mm, core diameter=0.2 mm) as shown in FIG. 5
<3-(3)>
[0060] A core-containing tape-shaped product was formed by
co-extrusion in the same manner as in the above 3-(2), and then
stretched at 6.25 times in a hot air oven at 180.degree. C. and
further relaxed by 10% in a hot air oven at 220.degree. C. to
obtain a core-containing tape-shaped product (width=0.65 mm,
thickness=0.24 mm, core diameter=0.2 mm) as shown in FIG. 5
<3-(4)>
[0061] A core-containing tape-shaped product (width=0.65 mm,
thickness=0.24 mm, core diameter=0.2 mm) as shown in FIG. 5 was
produced in the same manner as in the 3-(2) above except that a
stretch ratio was changed to 6.7 times.
[0062] From the above 3-(1) to 3-(4), these stretched
core-containing tape-shaped products obtained by forming a
tape-shaped product containing core-forming resin along both edges
thereof by extrusion and subsequent stretching failed to exhibit a
sufficient strength compared with the tape-shaped product obtained
by injection molding together with the stretched filament and, if
the stretching ratio was further increased for providing an
increased strength, were liable to cause a separation between the
cores and the tape.
Example 3
[0063] A 6/66-copolymer nylon resin having a relative viscosity of
3.5 was spun at a resin temperature of 230.degree. C. through a 50
mm-dia. extruder to obtain an unstretched filament. The unstretched
filament was subjected to a first step-stretching at 3.6 times in a
warm water bath at 85.degree. C. and then a second step-stretching
at 1.5 times in a hot air oven at 185.degree. C., followed by
relaxation by 15% in a hot air oven at 165.degree. C. to obtain a
stretched filament. The stretched filament exhibited a tensile
strength of 815 MPa and an elongation of 45%. Then, similarly as in
Example 1, the stretched filament was set in a mold for injection
molding as shown in FIGS. 3A and 3B, and an identical resin as the
stretched filament was injected at 240.degree. C. into the mold to
form a tape-shaped product as shown in FIG. 1. The stretched
filament occupied 40% of a sectional area perpendicular to a
longitudinal direction of the product. The tape-shaped product
exhibited excellent physical properties including a large tensile
strength of 581 MPa and a small thermal shrinkability of 0.3%.
Example 4
[0064] A polyvinylidene fluoride resin of .eta.inh=1.0 ("KF#1000",
made by Kureha Chemical Industry Co., Ltd) was spun at a resin
temperature of 260.degree. C. through a 50 mm-dia. extruder to
obtain an unstretched filament. The unstretched filament was
subjected to a first step-stretching at 5.6 times in a glycerin
bath at 170.degree. C. and then a second step-stretching at 1.15
times in a glycerin bath at 165.degree. C., followed by relaxation
by 10% in a glycerin bath at 160.degree. C. to obtain a stretched
filament. The stretched filament exhibited a tensile strength of
752 MPa and an elongation of 35%. Then, similarly as in Example 1,
the stretched filament was set in a mold for injection molding as
shown in FIGS. 3A and 3B, and an identical resin as the stretched
filament was injected at 240.degree. C. into the mold to form a
tape-shaped product as shown in FIG. 1. The stretched filament
occupied 40% of a sectional area perpendicular to a longitudinal
direction of the product. The tape-shaped product also exhibited
excellent physical properties similarly as the tape-shaped product
of Example 3.
Example 5
[0065] The same 6/66 copolymer nylon as used in Example 3 was
formed into a stretched filament of 200 .mu.m in the same manner as
in Example 3 except for changing a second stretching ratio to 1.4
times. This stretched filament exhibited a tensile strength of 761
MPa. Then, similarly as in Example 1, the stretched filament was
set in a mold for injection molding, and an identical resin as in
Example 4 was injected at 240.degree. C. into the mold to form a
tape-shaped product as shown in FIG. 1. The stretched filament
occupied 40% of a sectional area perpendicular to a longitudinal
direction of the tape-shaped product. The tape-shaped product also
exhibited excellent physical properties.
[0066] While the products of both Examples 4 and 5 exhibited
excellent physical properties, the tape-shaped product of Example 4
exhibited a better physical property in spite of almost equal
strengths of the stretched filaments in these Examples. This is
attributable to a difference in adhesion between the resin of the
stretched filament and the injected resin. Thus, better adhesion
between a stretched filament and an injected resin results in
better development of a property of the stretched filament in a
tape-shaped product.
Example 6
[0067] A polyester resin (IV=1.0) was spun at a resin temperature
of 275.degree. C. through a 50 mm-dia. extruder to obtain an
unstretched filament. The unstretched filament was stretched at 5.5
times and then relaxed by 15% to obtain a stretched filament. Then,
similarly as in Example 1, the stretched filament was set in a mold
for injection molding as shown in FIGS. 3A and 3B, and an identical
resin as in Example 1 was injected at 280.degree. C. into the mold
to form a tape-shaped product as shown in FIG. 1. The stretched
filament occupied 40% of a sectional area perpendicular to a
longitudinal direction of the product. The tape-shaped product
exhibited similarly excellent physical properties as the product of
Example 3.
Comparative Example 4
[0068] A stretched filament-containing tape-shaped product was
prepared by injection of a resin different from that of the
stretched filament.
4-(1)
[0069] A core-containing unstretched tape was formed by
co-extrusion of an identical polyester resin as used in Example 6
and a polyester elastomer of MFR=1.0. The tape was then subjected
to stretching and relaxation heat treatment in a similar manner as
in Example 6 to obtain a core-containing stretched tape-shaped
product (width=0.65 mm, thickness=0.24 mm, core diameter=0.2 mm).
As is understood from the physical properties shown in Table 1, the
tape-shaped product exhibited a sufficient strength but failed to
exhibit size stability due to a large thermal shrinkability.
4-(2)
[0070] A tape-shaped product was tried to be formed in the same
manner as in Example 1 except for using a stretched filament of
polyvinylidene fluoride resin obtained in the same manner as in
Example 4 and a polyester elastomer of MFR=10 identical to the one
used in Example 1, but the stretched filament of polyvinylidene
fluoride resin was melted at a time of injection molding.
TABLE-US-00001 TABLE 1 Stretched filament Shaped product Strength
Tape portion Strength Shink Example Shaping method* Material**
[MPa] core Material** [Mpa] [%] 1 SF-inserted injection PEE MFR10
470 PEE MFR10 338 0.3 Comp. 1-(1) injection PEE MFR10 61 0.1 Comp.
1-(2) USF-inserted injection PEE MFR10 PEE MFR10 65 0.1 Comp. 2-(1)
tape extrusion PEE MFR10 70 0.1 Comp. 2-(2) tape
extrusion-stretching PEE MFR10 235 2.5 Comp. 2-(3) '' PEE MFR10 198
0.3 Comp. 2-(4) '' PEE MFR10 293 3.3 2 SF-inserted injection core:
PEE MFR10 437 PEE MFR10 320 0.3 sheath: PEE MFR17 Comp. 3-(1)
core/tape extrusion yes core: PEE MFR10 71 0.1 sheath: PEE MFR 17
Comp. 3-(2) core/tape extrusion-stretching yes core: PEE MFR10 198
2.3 sheath: PEE MFR 17 Comp. 3-(3) '' yes core: PEE MFR10 179 0.3
sheath: PEE MFR 17 Comp. 3-(4) '' yes core: PEE MFR10 250 3.1
sheath: PEE MFR 17 3 SF-inserted injection 6/66 copolymer nylon 815
6/66 copolymer nylon 581 0.3 4 '' PVDF 752 PVDF 522 0.3 5 '' 6/66
copolymer nylon 761 PVDF 419 0.3 6 '' polyester 653 PEE MFR 10 455
0.3 Comp. 4-(1) core/tape extrusion-stretching yes core: polyester
365 3 sheath: PEE MFR 10 Comp. 4-(2) SF-inserted injection PVDF 752
PEE MFR 10 PVDF melted *Abbriviation used: SF = stretched filament,
USF = unstretched filament **Abbreviation used: PEE = polyester
elastomer, MFR = melt flow rate, PVDF = polyvinylided fluoride
[0071] Next, examples of production of ball chain belts are
described.
Example 7
[0072] As shown in FIG. 7, balls were set at equal intervals in a
mold, a stretched filament prepared in Example 1 was disposed at
such positions as to be contained along two edges parallel to a
longitudinal direction of a resultant shaped product, and an
identical resin (polyester elastomer of MFR=1.0) as the stretched
filament was injected into the mold to obtain a ball chain belt as
shown in FIG. 2 having a width of 2.24 mm, a thickness of 0.24 mm,
a hole diameter of 1.63 mm and a hole-hole pitch of 1.73 mm. The
stretched filament occupied a portion of sectional area
perpendicular to the longitudinal direction at ratios of 5% at a
ball retainer portion (spacer portion) and 43% at a hole diameter
position. As physical properties thereof are shown in Table 2, the
ball chain belt exhibited a high tensile strength and also a high
strength at the ball-retainer portion, and further good size
stability due to a small thermal shrinkability. The stretched
filament exhibited good adhesiveness without peeling.
Comparative Example 5
[0073] A ball chain belt (width=2.24 mm, thickness=0.24 mm, hole
diameter=1.63 mm, hole-hole pitch=1.73 mm) as shown in FIGS. 8A-8C
(wherein a dashed line 7 represents a ball-inset state) was
obtained by injection molding in the same manner as in Example 7
except for omitting the stretched filament.
Example 8
[0074] A tape-shaped product having a width of 2.24 mm and a
thickness of 0.24 mm prepared in a similar manner as in Example 1
was perforated to form holes having a diameter of 1.63 mm at a
hole-hole pitch of 1.73 mm. Then, this perforated tape-shaped
product was set in a mold, balls for molding were inset in the
holes thereof, and insert molding was performed by injecting a
polyester elastomer of MFR=10 to obtain a ball chain belt as shown
in FIG. 2.
Comparative Example 6
[0075] Tape-shaped products of different stretching ratios were
perforated and subjected to insert molding in similar manners as in
Example 8 to produce ball chain belts.
6-(1)
[0076] An identical resin (polyester elastomer of MFR=10) as used
in Example 7 was extruded through a 50 mm-dia. extruder to form a
tape product (width=2.24 mm, thickness=0.24 mm) as shown in FIG. 4,
which was then perforated to form holes having a diameter of 1.63
mm at a hole-hole pitch of 1.73 mm as shown in FIG. 6. Then, this
perforated tape-shaped product was set in a mold, balls for molding
were inset in the holes, and insert molding was performed to obtain
a ball chain belt as shown in FIG. 8.
6-(2)
[0077] An identical resin as used in Example 7 was extruded into a
tape-shaped product in the same manner as in the above 6-(1), which
was then stretched at 5.8 times in a hot air oven at 150.degree. C.
and then relaxed by 10% in a hot air oven at 180.degree. C. to
obtain a stretched tape. This tape was used for perforation and
insert molding in the same manner as in the above 6-(1) to obtain a
ball chain belt as shown in FIG. 8.
6-(3)
[0078] A ball chain belt was obtained in the same manner as in the
above 6-(2) except for changing a stretching ratio to 6.9
times.
6-(4)
[0079] An identical resin as used in Example 7 was extruded into a
tape-shaped product in the same manner as in the above 6-(1), which
was then stretched at 6.25 times in a hot air oven at 180.degree.
C. and then relaxed by 30% in a hot air oven at 220.degree. C. to
obtain a stretched tape. This tape was used for perforation and
insert molding in the same manner as in the above 6-(1) to obtain a
ball chain belt as shown in FIG. 8.
[0080] In the above 6-(1) to 6-(4), there occurred molding
failures, such as insufficient filling of resin at spacer portions
and "fins" caused by entering of resin into holes.
Example 9
[0081] Insert molding was performed in the same manner as in
Example 7 except for using a core/sheath composite stretched
filament obtained in Example 7 to prepare a ball chain belt as
shown in FIG. 2.
Comparative Example 7
[0082] Core-containing composite tapes were prepared by
co-extruding a polyester elastomer of MFR=10 as a core resin
together with a polyester elastomer of MFR=17, and used for
production of ball chain belts as shown in FIGS. 9A-9C, wherein a
dashed line 7 represents a ball-inset state.
7-(1)
[0083] A composite tape containing a core was prepared by
co-extruding a polyester elastomer of MFR=10 as a core resin
together with a polyester elastomer of MFR=17. This tape was
subjected to perforation and insert molding in the same manner as
in Example 6 to obtain a ball chain belt as shown in FIGS.
9A-9C.
7-(2)
[0084] A core-containing composite tape was prepared by
co-extruding a polyester elastomer of MFR=10 as a core resin
together with a polyester elastomer of MFR=17, followed by
stretching at 5.8 times in a hot air oven at 150.degree. C.,
followed by relaxation by 10% in a hot air oven at 180.degree. C.
to obtain a stretched tape. This tape was subjected to perforation
and then insert molding in the same manner as in Comparative
Example 6 to obtain a ball chain belt as shown in FIGS. 9A-9C.
7-(3)
[0085] A ball chain belt was obtained in the same manner as in the
above 7-(2) except for changing a stretching ratio to 6.7
times.
7-(4)
[0086] A core-containing composite tape was prepared by
co-extruding a polyester elastomer of MFR=10 as a core resin
together with a polyester elastomer of MFR=17, followed by
stretching at 6.25 times in a hot air oven at 180.degree. C.,
followed by relaxation by 30% in a hot air oven at 220.degree. C.
to obtain a stretched tape. This tape was subjected to perforation
and then insert molding in the same manner as in Comparative
Example 6 to obtain a ball chain belt as shown in FIGS. 9A-9C.
[0087] In any case of the above 7-(1) to 7-(4), many defective
products occurred due to difficulty of molding, and products
obtained appeared normal but were far from practical use due to
small tensile strength and small strength at retaining
portions.
Example 10
[0088] A nylon stretched filament prepared in Example 3 was set in
a mold as shown in FIG. 7, and an identical resin as the stretched
filament was injected into the mold to obtain a ball chain belt
(width=2.24 mm, thickness=0.24 mm, hole diameter=1.63 mm, hole-hole
pitch=1.73 mm) as shown in FIG. 2 in a similar manner as in Example
7.
Example 11
[0089] A polyvinylidene fluoride resin stretched filament prepared
in Example 4 was set in a mold as shown in FIG. 7, and an identical
resin as the stretched filament was injected into the mold to
obtain a ball chain belt (width=2.24 mm, thickness=0.24 mm, hole
diameter=1.63 mm, hole-hole pitch=1.73 mm) as shown in FIG. 2 in a
similar manner as in Example 7.
Example 12
[0090] A nylon stretched filament prepared in Example 5 was set in
a mold as shown in FIG. 7, and an identical resin as the stretched
filament was injected into the mold to obtain a ball chain belt
(width=2.24 mm, thickness=0.24 mm, hole diameter=1.63 mm, hole-hole
pitch=1.73 mm) as shown in FIG. 2 in a similar manner as in Example
7. The stretched filament occupied a portion of sectional area
perpendicular to a longitudinal direction at ratios of 5% at a
ball-retainer portion (spacer portion) and 43% at a hole diameter
position.
[0091] The products of Examples 11 and 12 both exhibited excellent
results. A reason why the product of Example 11 exhibited better
properties is that adhesion between the stretched filament and the
injected resin was better in Example 11, similarly as in the case
of Examples 4 and 5.
Comparative Example 8
[0092] A polyvinylidene fluoride resin stretched filament prepared
in Example 4 was set in a mold as shown in FIG. 7, and a polyester
elastomer of MFR=10 was injected into the mold for insert molding
to produce a bal chain belt (width=2.24 mm, thickness=0.024 mm,
hold diameter=1.63 mm, hole-hole pitch=1.73 mm) as shown in FIG. 2,
in a similar manner as in Example 7, whereas the polyvinylidene
fluoride resin was melted at a time of the insert molding.
Example 13
[0093] A polyester stretched filament prepared in Example 6 was set
in a mold as shown in FIG. 7, and a polyester elastomer of MFR=10
was injected into the mold to obtain a ball chain belt (width=2.24
mm, thickness=0.24 mm, hole diameter=1.63 mm, hole-hole pitch=1.73
mm) as shown in FIG. 2 in a similar manner as in Example 7.
[0094] The ball chain belts prepared in the above Examples 7-13 all
exhibited sufficiently large tensile strength and strength at the
retaining portion, thus exhibiting excellent performances as a ball
chain belt.
Comparative Example 9
[0095] Glass fiber (multi-filaments in a form of bundle of 120
filaments of each 9.4 .mu.m in diameter) wound about a bobbin was
supplied to a die and polyester elastomer used in Example 7 was
heated through an extruder and supplied to the die to be extruded
so as to cover the glass fiber, thereby obtaining a core-containing
composite tape-shaped product as shown in FIG. 5. Then, the
tape-shaped product was subjected to perforation and insert molding
in a similar manner as in Comparative Example 6 to obtain a ball
chain belt as shown in FIGS. 9A-9C, wherein adhesion between the
glass fiber and the polyester elastomer was insufficient to cause
peeling of the glass fiber and cutting of filaments.
Comparative Example 10
[0096] A ball chain belt as shown in FIGS. 9A-9C was prepared in
the same manner as in Comparative Example 9 except for using carbon
fiber (multifilaments in a form of bundle of 80 filaments, each
being 10 .mu.m in diameter). In the belt, adhesion between the
carbon fiber and the polyester elastomer was insufficient to cause
peeling of the carbon fiber and cutting of filaments.
TABLE-US-00002 TABLE 2 Ball retainer Stretched filament Injection
Tensile Retaining Thermal Shaping Strength Extruded Perfora- molded
strength strength shrink Molding Example method* Material** [MPa]
tape material** tion material** [MPa] [MPa] [%] defects*** 7
SF-inserted PEE MFR10 470 213 73 0.3 A injection Comp. 5 injection
PEE MFR10 61 53 0.3 A 8 Method 1 PEE MFR10 470 yes PEE MFR10 207 38
0.3 B Comp. 6-(1) Method 2 PEE MFR10 yes PEE MFR10 70 37 0.1 C
Comp. 6-(2) Method 3 PEE MFR10 yes PEE MFR10 113 35 3.1 C Comp.
6-(3) Method 3 PEE MFR10 yes PEE MFR10 195 35 3.8 C Comp. 6-(4)
Method 3 PEE MFR10 yes PEE MFR10 98 37 0.3 C 9 SF-inserted core:
PEE MFR10 437 PEE MFR10 208 110 0.3 A injection sheath: PEE MFR17
Comp. 7-(1) Method 4 core: PEE MFR10 yes PEE MFR10 68 35 0.2 C
sheath: PEE MFR17 Comp. 7-(2) Method 5 core: PEE MFR10 yes PEE
MFR10 100 35 2.8 C sheath: PEE MFR17 Comp. 7-(3) Method 5 core: PEE
MFR10 yes PEE MFR10 165 34 3.3 C sheath: PEE MFR17 Comp. 7-(4)
Method 5 core: PEE MFR10 yes PEE MFR10 89 38 0.3 C sheath: PEE
MFR17 10 SF-inserted 6/66 co-Ny 815 6/66 co-Ny 464 140 0.2 A
injection 11 SF-inserted PVDF 752 PVDF 383 131 0.3 A injection 12
SF-inserted 6/66 co-Ny 761 PVDF 311 86 0.3 A injection 13
SF-inserted polyester 653 PEE MFR10 329 130 0.3 A injection Comp. 8
PVDF 752 PEE MFR10 melted Comp. 9 Method 4 core: glass fiber yes
PEE MFR10 melted sheath: PEE & cut Comp. 10 Method 4 core:
carbon fiber yes PEE MFR10 melted sheath: PEE & cut *SF =
stretched filament; Method 1 = SF-inserted injection.fwdarw.
perforation.fwdarw. injection molding of spacer portion. Method 2 =
tape extrusion.fwdarw. perforation.fwdarw. injection molding of
spacer portion Method 3 = tape extrusion.fwdarw. stretching.fwdarw.
perforation.fwdarw. injection molding of spacer portion Method 4 =
extrusion of core-containing tape.fwdarw. perforation.fwdarw.
injection molding of spacer portion Method 5 = extrusion of
core-containing tape.fwdarw. stretching.fwdarw. perforation.fwdarw.
injection molding of spacer portion **PEE = polyester elastomer,
PVDF = polyvinylidene flouride, co-Ny = copolymer nylon. ***molding
defects (insufficient filling, fins) A = none, B = few, C =
many
Example 14
[0097] As shown in FIG. 11, rollers were set at equal intervals in
a mold, and a stretched filament prepared in Example 1 was disposed
at such positions as to be contained along two edges parallel to a
longitudinal direction of a resultant shaped product, and an
identical resin (polyester elastomer of MFR=1.0) as the stretched
filament was injected into the mold to obtain a roller-type ball
chain belt as shown in FIGS. 12A-12C having a width of 2.24 mm, a
thickness of 0.24 mm, a hole in a width direction of 1.63 mm and a
hole-hole pitch of 1.73 mm. The stretched filament occupied a
portion of sectional area perpendicular to the longitudinal
direction at ratios of 5% at a roller-retainer portion (spacer
portion) and 43% at a hole diameter position. The roller-type ball
chain belt exhibited a high tensile strength and also a high
strength at the ball-retainer portion, and further exhibited good
size stability due to a small thermal shrinkability. The stretched
filament exhibited good adhesiveness without peeling.
Example 15
[0098] A ball chain was prepared by insetting balls in a ball chain
belt obtained in the same manner as in Example 7. The ball chain
was used to prepare a linear motion guide device as shown in FIG.
13 including a tracking rail 12, a moving block body 13 and ball
chain 14.
Example 16
[0099] A roller-type ball chain was prepared by insetting rollers
in a ball chain belt obtained in the same manner as in Example 14.
The ball chain was used to prepare a linear motion guide device 15
as shown in FIG. 14 including a tracking rail 16, a moving block
body 17 and roller-type ball chain 18.
Example 17
[0100] A ball chain was prepared by insetting balls in a ball chain
belt obtained in the same manner as in Example 7. The ball chain
was used to prepare a ball screw 19 as shown in FIG. 15 including a
screw shaft 20, a nut member 21, a return pipe 22 and ball chain
23.
[0101] It became clear that the linear motion guide devices
prepared in Examples 14 and 15, and the ball screw prepared in
Example 17, all withstood a long period of use, whereby it was
proved that the ball chain belt and ball chain according to the
present invention could be excellent members of such linear motion
guide device and ball screw device.
INDUSTRIAL APPLICABILITY
[0102] According to the present invention of effecting injection
molding after setting a stretched fibrous member in a mold, it is
possible to obtain a tape-shaped product having a large strength
that is not attainable by a conventional extrusion product or a
mere injection-molded product.
[0103] Further, a ball chain belt having a large strength obtained
by subjecting such a tape-shaped product to perforation and
injection molding of portions for retaining rolling members (such
as balls or rollers) or by injection molding after setting a
stretched fibrous member and balls for molding, is allowed to
provide a product which exhibits a large strength not realizable by
a ball chain belt formed by (co-)extrusion. Further, the stretched
fibrous member disposed along both edges of the tape-shaped product
not only contributes to strength but also reinforces a weld and
remarkably reduces molding defects.
[0104] By insetting prescribed balls (or rollers) in the ball chain
belt thus-obtained of the present invention, a ball chain is
obtained. The ball chain can exhibit excellent performances when
incorporated in a linear motion guide device equipped with an
endless circulation path, or a ball screw, and the like.
* * * * *