U.S. patent application number 11/724239 was filed with the patent office on 2007-07-05 for method of manufacturing laminated mold and laminated mold.
This patent application is currently assigned to KABUSHIKI KAISHA BRIDGESTONE. Invention is credited to Gyoei Iwamoto, Takehiro Kata, Yuichiro Ogawa.
Application Number | 20070155290 11/724239 |
Document ID | / |
Family ID | 30002329 |
Filed Date | 2007-07-05 |
United States Patent
Application |
20070155290 |
Kind Code |
A1 |
Kata; Takehiro ; et
al. |
July 5, 2007 |
Method of manufacturing laminated mold and laminated mold
Abstract
For manufacturing the laminated mold comprising the laminate
(11) being formed of a plurality of thin sheets (11a) laminated on
each other, laminate the thin sheets with the excess portions of
respective thin sheets exceeding the profile of the tire crown
portion on the side of contacting with the tire stepping face left,
then remove the excess portions, form the sector mold by placing
the laminate (11) with the excess portions removed in the holder,
form the laminated mold having the annular read pattern by
arranging a plurality of the sector mold in a peripheral direction
of the tire so as to suppress formation of the stepped shape
appearing on the tire profile comparing with the one as originally
intended.
Inventors: |
Kata; Takehiro; (Tokyo,
JP) ; Ogawa; Yuichiro; (Tokyo, JP) ; Iwamoto;
Gyoei; (Tokyo, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 19928
ALEXANDRIA
VA
22320
US
|
Assignee: |
KABUSHIKI KAISHA
BRIDGESTONE
TOKYO
JP
|
Family ID: |
30002329 |
Appl. No.: |
11/724239 |
Filed: |
March 15, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10518017 |
Dec 14, 2004 |
|
|
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PCT/JP03/08342 |
Jul 1, 2003 |
|
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11724239 |
Mar 15, 2007 |
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Current U.S.
Class: |
451/38 |
Current CPC
Class: |
Y10T 29/49826 20150115;
B29D 2030/0609 20130101; B23P 15/246 20130101; B29D 30/0606
20130101; B29C 33/302 20130101 |
Class at
Publication: |
451/038 |
International
Class: |
B24C 1/00 20060101
B24C001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 1, 2002 |
JP |
2002-191827 |
Jul 8, 2002 |
JP |
2002-198586 |
Claims
1. A manufacturing method of a laminated mold comprising a laminate
being formed by laminating a plurality of thin sheets in a
widthwise direction or in a peripheral direction of a tire
comprising the steps of, previously tapering respective thin sheets
on the side of a tire stepping face so as to have an angle
approximately the same angle corresponding to the profile of a tire
crown portion, and after tapering the thin sheets, proceeding
lamination of those thin sheets.
2. The manufacturing method of the laminated mold according to
claim 1, the thin sheets are tapered by a laser machining.
3. The manufacturing method of the laminated mold according to
claim 1, the thin sheets are tapered by a shot blast.
4. A laminated mold comprising of a laminate being formed of a
plurality of thin sheets laminated in a peripheral direction of a
tire, characterized in that bumps are provided on the lamination
surfaces of respective thin sheets in a thicknesswise direction
thereof so that thin sheets are caused to mutually abut in a
laminationwise direction through the bumps so as to fix spacing
between the thin sheets.
5. A laminated mold consisting of a laminate according to claim 4
characterized in that the bumps are formed by a press work.
6. A laminated mold consisting of a laminate according to claim 4
characterized in that thickness of the thin sheets falls in the
range of 0.1.about.3 mm.
7. The manufacturing method of the laminated mold according to
claim 1, when laminating a plurality of the thin sheets in a
peripheral direction of the tire comprising the steps of, providing
bumps on lamination surfaces of respective thin sheet in a
thicknesswise thereof so that the thin sheets are caused to
mutually abut in a laminationwise direction through the bumps so as
to fix spacing between the thin sheets.
8. The manufacturing method of the laminated mold according to
claim 2, when laminating a plurality of the thin sheets in a
peripheral direction of the tire comprising the steps of, providing
bumps on lamination surfaces of respective thin sheet in a
thicknesswise thereof so that the thin sheets are caused to
mutually abut in a laminationwise direction through the bumps so as
to fix spacing between the thin sheets.
9. The manufacturing method of the laminated mold according to
claim 3, when laminating a plurality of the thin sheets in a
peripheral direction of the tire comprising the steps of, providing
bumps on lamination surfaces of respective thin sheet in a
thicknesswise thereof so that the thin sheets are caused to
mutually abut in a laminationwise direction through the bumps so as
to fix spacing between the thin sheets.
10. A laminated mold consisting of a laminate according to claim 5
characterized in that thickness of the thin sheets falls in the
range of 0.1.about.3 mm.
Description
[0001] This is a Division of application Ser. No. 10/518,017 filed
Dec. 14, 2004, which in turn is a National Stage Application of
International Application No. PCT/JP03/08342 filed Jul. 1, 2003.
The disclosures of the prior applications are hereby incorporated
by reference herein in their entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] Present invention relates to a manufacturing method of a
tire mold for molding a tire with vulcanization and specifically
related to the laminated mold provided with a laminate consisting
of a plurality of thin sheets laminated on each other in a
widthwise direction and a manufacturing method thereof.
[0004] 2. Description of the Prior Art
[0005] As shown by FIG. 8(a) and FIG. 8(b), so far has been used a
vulcanization metal mold (50) comprising a plurality of sector
molds (53) annularly coupled each of which is formed of a holder
(52) by which a crown portion metal mold (51) having a cross
sectional shape of the tire crown portion is held and the surface
of a raw tire being already molded is press fit to an inner wall of
the heated vulcanization mold (50) by pressurizing inner side of
the molded tire and such application of heat and pressure to raw
rubber has been employed as a method of vulcanization of tire.
Usually, the above crown portion metal mold (51) can be
manufactured by casting and yet, because such a casting mold not
only costs much labour but also material cost is high, recently for
meeting purpose of attaining low cost and reduction in delivery
date in place of the above crown portion metal mold (51), which is
a casting mold, a laminated mold as shown by FIG. 9(a) and FIG.
9(b) has become in use wherein the laminated mold comprises an
annular tread pattern molding portion being formed by arranging a
plurality of sector molds (63) in a peripheral direction of the
tire wherein the crown portion metal mold (61), which consists of
the laminate being formed of a plurality of thin sheets laminated,
held by the holder (62) constitutes the sector mold (63). In this
description (61s) denotes a lamination surface of the thin sheet
(61), (61p) denotes an end face of the thin sheet on the side of
the holder (62) and (61q) denotes an end face of the thin sheet on
the side of contacting with the face of the tire stepping on the
road surface (hereinafter, the wording "the face of the tire
stepping on the road surface" is shortened to read "the tire
stepping face").
[0006] In view of automating and speeding up the manufacturing, the
thin sheet (61a) is generally formed by means of a laser machining
with 2DCAM. Thus formed thin sheets (61a) are laminated to form the
laminate to be used as the crown portion metal mold (61) and by
placing the crown portion metal mold (61) in the holder (62), the
sector mold (63) having the laminate as the crown portion metal
mold can be formed. Concretely speaking, as shown by FIG. 10 the
thin sheet materials (61z) are cut at respective both ends by
casting a laser beam perpendicularly to those thin sheet materials
(61z) to become rectangularly shaped cross section and those thin
sheet (61a) having thus formed rectangularly shaped cross section
are laminated in a widthwise direction of the tire to form the
tread pattern molding portion.
[0007] However, as long as relying on the above method, as shown by
FIG. 9(a) due to the fact that the cross section of the thin sheet
(61a) is rectangularly shaped, the crown portion metal mold (61),
which is formed by coupling end faces (61q) of respective thin
sheets (61a), inevitably becomes to have a profile stepped by the
amount corresponding to the thickness of the thin sheets (61a)
having the rectangularly shaped cross section. Accordingly, there
have arisen problems such that not only appearance of the
vulcanized tire is inferior but also its performance is inferior
than that of the vulcanized tire manufactured through the casting
mold currently in use. Furthermore, possibility of degradation in
durability is anticipated because many protrusions with acute angle
appear on the tire stepping face.
[0008] Further, in the case where the thin sheets are laminated in
a peripheral direction of the tire, though close contact between
those thin sheets can be assured on the inner side of radial
direction, but on the outer side thereof gaps are inevitably
produced therebetween and not only opening and closing operation of
the mold becomes unstable but also degradation in its durability
will be caused.
[0009] The present invention is made to cope with those problems so
far have arisen and thus object of the present invention to provide
a method for manufacturing the laminated mold capable of
suppressing formation of stepped shape appearing on its profile
comparing with the one as originally intended.
SUMMARY OF THE INVENTION
[0010] The invention of the second aspect provides the
manufacturing method of the laminated mold comprising the laminate
being formed of a plurality of thin sheets laminated in a widthwise
direction or in a peripheral direction of the tire, and the
manufacturing method is characterized in comprising the steps of
laminating those thin sheets under the condition that the excess
portions of them, which exceed the shape of the tire crown portion,
are left on the side contacting with the tire stepping face, and
after proceeding the lamination step removal of the excess portions
is carried out by means of a shot blast. By virtue of such a
process, the profile of the laminated mold on the side of the tire
stepping side can be formed quite the same with that of the tire as
originally intended, and as a result the tire, which has both of
the profile and the performance equivalent to those obtained
through the casting mold currently in use, can become to be
realizable easily. It is noted that, though the profile of the tire
crown portion as given above is generally meant by that which is
taken in a widthwise direction but nevertheless the present
invention also includes the profile taken in a peripheral direction
of the tire crown portion such as change in depth of grooves in a
peripheral direction of the tire.
[0011] The manufacturing method of the laminated mold according to
the invention of the second aspect characterized in that the
removal of the excess portions according to the invention of the
first aspect is carried out by means of the shot blast.
[0012] The manufacturing method of the laminated mold according to
the invention of the third aspect is characterized in that the
material to be injected (hereinafter "the material to be injected"
shortened to read "injection material") according to the invention
of the second aspect is limited to aluminum powder.
[0013] The manufacturing method of the laminated mold according to
the invention of the fourth aspect characterized in that removal of
the excess portions according to the second aspect or the third
aspect is carried out after masking boundary portions of respective
thin sheets.
[0014] The invention of the fifth aspect provides the manufacturing
method of the laminated mold comprising the laminate being formed
of a plurality of thin sheets laminated in a widthwise direction or
in a peripheral direction of the tire, wherein those thin sheets on
the side of the tire stepping face are tapered in advance so as to
bring those tapered portion thereof to have the taper angle
approximately equal to the angle corresponding to that of the
profile of the crown portion and after tapering them those tapered
thin sheets are laminated. Through this process of manufacturing
method, by a simple machining the profile of the laminated mold on
the side of the tire stepping face can be approximated to the one
as originally intended.
[0015] The manufacturing method of the laminated mold according to
the invention of the sixth aspect, the tapering work according to
the fifth aspect is carried out by a laser machining.
[0016] The manufacturing method of the laminated mold according to
the invention of the seventh aspect, the tapering work according to
the fifth aspect is carried out by means of a shot blast.
[0017] The manufacturing method of the laminated mold according to
the invention of the eighth aspect is characterized in that when
laminating a plurality of thin sheets in a peripheral direction of
the tire according either one of the first through seventh aspect,
bumps are provided on respective lamination surfaces of thin sheets
in a thicknesswise direction thereof, those thin sheets are caused
to mutually abut therebetween in a lamination direction through
those bumps so as to secure those thin sheets with a fixed spacing,
enabling to secure them in a close contact therebetween, thereby
stabilizing opening and closing operation of the mold and also
improving the durability of the mold further.
[0018] The invention of the ninth aspect provides the laminated
mold comprising the laminate being formed of a plurality of thin
sheets laminated in a widthwise direction of the tire characterized
in that bumps are provided on the lamination surfaces of respective
thin sheets protruding in a thicknesswise thereof so that those
thin sheets are caused to mutually abut in a laminationwise
direction, there by securing those thin sheets with a fixed
spacing.
[0019] The laminated mold according to the invention of the tenth
aspect characterized in that the bumps provided on respective thin
sheets according to the ninth aspect are formed by a press
work.
[0020] The laminated mold according to the eleventh aspect
characterized in that the thickness of the thin sheets according to
the ninth or tenth aspect is limited to fall in the arrange of
0.1.about.3 mm.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 shows a constitution of the sector mold used for the
laminated mold presented in the most preferable Embodiment 1 of the
present invention.
[0022] FIG. 2(a) and FIG. 2(b) shows a working process for
for.rning the laminate presented in the most preferable Embodiment
1 of the present invention.
[0023] FIG. 3(a) and FIG. 3(b) show another example of constitution
of the sector mold used for the laminated mold of the present
invention.
[0024] FIG. 4(a) and FIG. 4(b) show a working process for forming
the thin sheets used for the laminated mold as given in FIG. 3.
[0025] FIG. 5(a), FIG. 5(b) and FIG. 5(c) show a method of
laminating thin sheets having bumps according to the present
invention.
[0026] FIG. 6(a) and FIG. 6(b) show another example of working
process for forming the laminate according to the present
invention.
[0027] FIG. 7(a) and FIG. 7(b) show a working process for forming
the thin sheets presented in the most preferable Embodiment 2.
[0028] FIG. 8(a) and FIG. 8(b) show a schematic diagram of a
vulcanization metal mold of the prior art.
[0029] FIG. 9(a) and FIG. 9(b)show a schematic diagram of a
laminated mold of the prior art.
[0030] FIG. 10 shows a working process for forming a thin sheet of
the prior art.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0031] A preferred embodiment of the present invention will be
described hereinunder with reference to the accompanying
drawings.
[0032] FIG. 1 shows a constitution of the sector mold (10) used for
the laminated mold exemplified in the most preferable Embodiment 1
and in this drawing the reference numeral (11) denotes the laminate
(crown portion metal mold) consisting of a plurality of thin sheets
(11a) laminated in a widthwise direction of the tire, (12) denotes
the sector holder (hereinafter named as "holder") for holding the
laminate (11) therein. In this Embodiment, when forming the
laminate (11), as shown by FIG. 2(a) those thin sheets (11a) are
laminated under the condition that the excess portions, which is
the portion exceeding the profile of the tire crown portion (tire
profile) as denoted by the line L, are left to the end face (11q)
of respective thin sheets (11a) on the side contacting with the
tire stepping face, and after those thin sheets have been
laminated, as shown by FIG. 2(b) the excess portions are removed by
means of a machining so as to reduce the profile of the mold on the
side of the tire stepping face to the tire profile L as originally
intended. By virtue of this process, profile of the laminate (11)
of the tire stepping face, which so far has been obliged to exhibit
the shape stepped by the level difference corresponding to the
thickness of the respective thin sheets (11a), can be reduced to a
smooth shape quite the same with that of a casting mold currently
in use.
[0033] Accordingly, as shown by FIG. 1, by arranging a plurality of
sector molds (10), which is formed by arranging the crown portion
metal mold consisting of the laminate (11) held in the holder (12),
in a peripheral direction of the tire, the laminated mold having
the annular tread pattern mold can be formed. The vulcanized tire
obtained through thus formed laminated mold is now released from
exhibiting the appearance of stepped shape resulting in that the
tire having the same performance with the one which is vulcanized
through the casting mold currently in use is available with low
cost and in a shortened period.
[0034] In the most preferable Embodiment 1 as above, though
description was made in the case where a plurality of thin sheets
(11a) are laminated in a widthwise direction of the tire and
nevertheless as shown by FIG. 3(a) and FIG. 3(b) the present
invention is also applicable to manufacture the sector mold (10A)
comprising the holder (12) for holding the laminate (13) being
formed of a plurality of thin sheets (13a) laminated in a
peripheral direction of the tire. In this case, as shown by FIG.
4(a), the thin sheets (13a) are laminated under the condition that
the excess portions, appearing at an end face (13q) of respective
thin sheets (13a) on the side of the tire stepping face are left
taking account of the profile taken in a peripheral direction of
the tire as denoted by K such as change in depth of grooves of the
tire in its peripheral direction, and as shown by FIG. 4(b) after
proceeding the lamination the excess portions are removed by a
machining work so that the profile of the mold on the side of the
tire stepping face become the same with that which is originally
intended.
[0035] It is noted that, in the case where a plurality of the thin
sheets (13a) are laminated in a peripheral direction of the tire,
though on the inner side of a radial direction, i.e. on the side of
the tire stepping face respective thin sheets (13a) contact closely
as shown by FIG. 5(a) and FIG. 5(b), but on the outer side as
thereof shown by FIG. 5(c) gaps are obliged to be produced. To cope
with this situation, it is preferable to provide a plurality of
bumps (14a, 14b, 14c) protruding in a thicknesswise direction of
respective thin sheets (13a) on their respective lamination
surfaces (13s) and as shown by FIG. 5(c) arrange those the thin
sheets (13a) to cause to mutually abut in a laminationwise
direction between those thin sheets, so as to secure a fixed
spacing therebetween. As a result, close contact between those thin
sheets (13a) can be made securely and opening and closing operation
of the mold can be stabilized and also durability of the mold can
be improved.
[0036] As to the foregoing structure, it is quite natural that the
amount of the protrusion (14) of the bumps are set higher as they
go outwardly of radial direction. Concretely speaking, amount of
the protrusion H is given by the formula 1, wherein A denotes
radius of the thin sheet (13a) up to the inner end in radial
direction, B denotes radius of the thin sheets (13a) up to the
outer end in radial direction, C denotes the dimension covering the
distance from outer end of the thin sheet (13a) in a radial
direction to the bump (14) and t denotes the thickness of the thin
sheet. Thus, Formula (1) is given as, Protrusion height
H={.pi.(B-2C)-.pi.A}/(.pi.A/t) {circle around (1)}
[0037] It is noted that provision of forming bumps (14) on the thin
sheets (13a) can be easily made by means of applying a press
molding to the metal sheet. In view of workability, thickness of
the above metal sheet (the shin sheet (13a)) is preferably chosen
to fall in the range of 0.1.about.3 mm when the thin sheet is
formed by means of a press molding.
[0038] In the above example, though description was made in the
case of removing the excess portions by means of a machine work,
and yet other means such as a laser machining or a shot blast can
be applicable to perform such a removal of the excess portions and
this is done as shown by FIG. 6(a) such that compressed air, which
is mixed with an injection material in a state of minute particles
(15p) such as abrasive sand, is forcibly sent and is blasted on to
the surface of the laminate (11) through a nozzle (15), thereby
polishing the inside surface of the laminate. The materials to be
sprayed are chosen depending on the material to be polished and
attached material among various materials such as fragments of
metals such as iron, copper, zinc, and aluminum and glass beads and
ceramic powder. Among them, ceramic powder having minute diameter
of particles and high hardness is preferable and still use of
aluminum powder is specifically preferred.
[0039] As shown by FIG. 6(b) prior to perform the shot blast, it is
preferable to coat the stepped valley portion (11k), which is a
boundary portion between those thin sheets (11a), with a removable
masking material (16) by peeling off such as vinyl chloride by
spraying the above material to that portion (11k) and after that it
is preferable to polish them by a shot blast. In this manner after
performing the shot blast profile of the laminate on the side of
the tire stepping face can be reduced certainly to a smoothly
finished surface being the same with that which is obtained by
means of casting mold currently in use. Furthermore, by performing
the above mentioned masking the thin sheets (11a) are protected
from entering of sprayed powder and fragments into minute gaps
between those thin sheets (11a) and in turn those minute gaps
therebetween can be alive, thereby securing the passages for
releasing air through those gaps during the mold being
proceeded.
The most preferable Embodiment 2.
[0040] Though in the Embodiment 1, the profile of the mold on the
side of the tire stepping face was reduced to the shape quite the
same with that which is denoted by L obtained by removing the
excess portions by a mechanical work after laminating those thin
sheets (11a) with those excess portions left thereto, and still
other than the foregoing as shown by FIG. 7(a) a laser work can be
applicable such that the laminate (crown portion metal mold) (11A)
consisting of thin sheets (11a) laminated can also be formed in
such a manner that firstly the thin sheets (11a) to be laminated on
the side of contacting with the tire stepping face are tapered by
means of a laser machining device (18) having a laser generator
(17) so as to make the angle essentially the same with the angle
corresponding to the profile of the crown portion, and after that
those thin sheets (11a), which have been thus tapered, are
laminated to form the laminate (11A). In this manner, as shown by
FIG. 7(b) by a simple working, profile of the mold on the side of
the tire stepping face can be approximated to the tire profile L as
originally intended. In this example, profile of the laminate (11A)
on the side of the tire stepping face becomes to the shape as shown
by the broken line and this manifests that, if the condition that
thickness and number of thin sheets (11a) to be laminated are
properly set, the vulcanized tire can be reduced to a sufficiently
smooth form. It is noted that the foregoing tapering work is not
limited to the laser machining but other means such as mechanical
machining and shot blast can be applicable.
INDUSTRIAL FEASIBILITY
[0041] As hitherto mentioned, according to the present invention
when manufacturing the laminated mold either one of procedures can
be employed: first, thin sheets are laminated under the condition
that excess portions of respective thin sheets on the side of the
tire stepping face, namely the portions exceeding the profile of
the tire crown portion, are left and after the lamination proceeded
those excess portions are removed, or alternatively, the thin
sheets on the side of the tire stepping face are tapered in advance
so that the tapered portions exhibit substantially the same angle
that which corresponds to the profile of the tire crown portion and
after this tapering work those thin sheets are laminated and thus
the profile of the laminated mold on the side of the tire stepping
face can be made the same with or approximately the same with the
profile as originally intended. In this manner, the tire having the
same profile with that which so far has been manufacture by means
of the casting mold currently in use can be realized with low cost
and in a shortened period.
* * * * *