U.S. patent application number 10/143370 was filed with the patent office on 2002-09-19 for punching apparatus for stamping and method for producing the same.
This patent application is currently assigned to NGK Insulators, Ltd.. Invention is credited to Kabe, Shusaku, Kitamura, Kazumasa, Matsubayashi, Satoshi, Noritake, Motoo, Tsuji, Hiroyuki.
Application Number | 20020129677 10/143370 |
Document ID | / |
Family ID | 17498544 |
Filed Date | 2002-09-19 |
United States Patent
Application |
20020129677 |
Kind Code |
A1 |
Tsuji, Hiroyuki ; et
al. |
September 19, 2002 |
Punching apparatus for stamping and method for producing the
same
Abstract
A stamping punch of a punching apparatus including a grip member
provided with crosspieces formed between long grooves on side walls
of a rectangular parallelepiped, and a plurality of punch members
which are formed integrally with the grip member. The respective
punch members are arranged in parallel to one another. A plurality
of holes are defined on a punch holder. A large amount of adhesive
is contained in the gap between joining surfaces when the grip
members of the stamping punches are inserted and secured into the
respective holes. Accordingly, the positional accuracy of the punch
member is improved, the accuracy of the hole defined through a
workpiece is improved, and it is possible to eliminate any fear of
occurrence of defect in shape. Further, the rigidity of the punch
member can be improved, the stripper is prevented from application
of unbalanced load, and the punch is easily exchangeable.
Inventors: |
Tsuji, Hiroyuki;
(Nagoya-City, JP) ; Kitamura, Kazumasa;
(Ichinomiya-City, JP) ; Noritake, Motoo;
(Ichinomiya-City, JP) ; Matsubayashi, Satoshi;
(Kitakyusyu-Shi, JP) ; Kabe, Shusaku;
(Kitakyusyu-Shi, JP) |
Correspondence
Address: |
BURR & BROWN
PO BOX 7068
SYRACUSE
NY
13261-7068
US
|
Assignee: |
NGK Insulators, Ltd.
Nagoya-City
JP
|
Family ID: |
17498544 |
Appl. No.: |
10/143370 |
Filed: |
May 10, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10143370 |
May 10, 2002 |
|
|
|
09401227 |
Sep 22, 1999 |
|
|
|
6408728 |
|
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Current U.S.
Class: |
76/101.1 ;
83/687 |
Current CPC
Class: |
Y10T 83/9476 20150401;
Y10T 83/943 20150401; H05K 3/005 20130101; B26F 1/02 20130101; B26D
7/2614 20130101; B26F 2210/08 20130101 |
Class at
Publication: |
76/101.1 ;
83/687 |
International
Class: |
B21K 021/00; B26F
001/14 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 25, 1998 |
JP |
10-271329 |
Claims
What is claimed is:
1. A method for producing a punching apparatus for stamping
comprising a punch holder secured to an upper die, a die member
secured to a lower die, a plurality of grip members detachably
fastened to said punch holder, and said plurality of punch members
formed on each of said plurality of grip members, said method
comprising said steps of: using a prism-shaped block as a material
for said grip member and said punch members; machining a plurality
of parallel long grooves separated from each other by arbitrary
spacing distances on two opposing side walls of said prism-shaped
block; machining tops of crosspieces formed between said long
grooves to have a circular arc-shaped configuration; machining long
grooves having an arbitrary depth on another side wall so that said
long grooves communicate with said long grooves on said two side
walls; simultaneously forming thereby said grip member including
said plurality of long grooves and said circular arc-shaped
crosspieces formed between said long grooves provided on said two
opposing side walls and said plurality of punch members each having
a lengthy rectangular cross section with its both ends provided
with circular arc-shaped portions; and defining a plurality of
holes each having a rectangular cross section on said punch holder
on the other hand, wherein: said grip member is fitted to said
punch holder with a gap such that said crosspieces formed on said
side walls of said grip member slidably contact with side walls of
said hole of said punch holder.
2. The method for producing said punching apparatus for stamping
according to claim 1, wherein said circular arc-shaped top of said
crosspiece formed on said side wall of said grip member and said
circular arc-shaped portion of said punch member are deformed to
include flat portions.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a division of U.S. application Ser. No.
09/401,227, filed Sep. 22, 1999, now allowed, the entirety of which
is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a punching apparatus for
stamping and a method for producing the same for applying
perforating machining to a sheet-shaped workpiece.
[0004] 2. Description of the Related Art
[0005] A punching apparatus for stamping has been hitherto used for
defining a plurality of holes through a sheet-shaped workpiece by
means of stamping machining. Such a punching apparatus for stamping
is constructed as follows. That is, a plurality of lengthy holes
1003 are defined through a metal plate or the like by means of
electric discharge machining (see FIG. 14A). The holes are
precisely finished by means of wire electric discharge machining to
produce a punch holder 1002 (see FIG. 14B).
[0006] As shown in FIG. 15, lengthy punch members 1004 having a
substantially rectangular cross section are inserted into the holes
1003 which are defined through the punch holder 1002 as described
above. Roots of the punch members 1004 are secured to the punch
holder 1002 by using, for example, an adhesive.
[0007] The punch members 1004 are slidably inserted into lengthy
holes 1006 of a stripper 1005 which is provided for the punching
apparatus for stamping. Further, the punch members 1004 are
inserted into lengthy holes 1008 which are defined through a die
1007.
[0008] When a plurality of lengthy holes 1011 are bored through a
workpiece 1009 such as a green sheet by using the stamping punching
apparatus 1001 constructed as described above, the workpiece 1009
is placed on the die 1007. When the punch members 1004 and the
stripper 1005 are moved downwardly, the lower surface of the
stripper 1005 firstly abuts against the upper surface of the
workpiece 1009. Subsequently, the punch members 1004 are moved
downwardly to apply the perforating machining to the workpiece
1009.
[0009] However, in the case of the conventional stamping punching
apparatus 1001 as described above, it is necessary that the hole
1003 is formed to be slightly larger than the dimension of the
punch member 1004 in order to insert the punch member 1004 into the
hole 1003. For this reason, a slight gap A is generated between the
punch member 1004 and the wall for forming the hole 1003 of the
punch holder 1002. Therefore, it is difficult to improve the
positional accuracy of the respective punch members 1004.
[0010] On the other hand, the holes 1006 defined through the
stripper 1005 are also formed to be slightly larger than the
rectangular dimension of the punch member 1004. For this reason, a
gap B exists between the punch member 1004 and the wall of the hole
1006. As a result, the error in positional accuracy of the punch
member 1004 is allowable within a range of the gap B. Therefore, a
problem arises in that the positional accuracy and the shape
accuracy are lowered for the hole 1011 of the workpiece 1009
subjected to the perforating machining performed by the stamping
punching apparatus 1001. Further, any unbalanced load is exerted on
the stripper 1005 through which the punch member 1004 is inserted.
It is feared that the punch member 1004 and the stripper 1005 may
be broken.
[0011] The hole 1008 of the die 1007 is formed to be larger than
the rectangular dimension of the punch member 1004 so that the
punch member 1004 is reliably inserted therethrough even when any
error exists in the rectangular dimension of the punch member 1004
or in the position of the punch member 1004 with respect to the
punch holder 1002. When the pitch between the punch members 1004 is
small, the gap between the hole 1008 and the adjoining hole 1008 is
narrow. Therefore, the following problem arises. That is, if there
is any difference in size between the gaps C1 and C2 generated
between the punch member 1004 and the walls for forming the hole
1008 of the die 1007, any inclination (deformation in the right or
left direction in FIG. 15) is caused by the gap A in the
non-punched portion D of the workpiece 1009, resulting in defect in
shape.
[0012] Although the respective punch members 1004 are formed to be
lengthy in the vertical direction in FIG. 15, their first ends are
merely supported by the punch holder 1002. Therefore, it is feared
that the punch member 1004 may be deformed by the load exerted on
the punch member 1004 during the stamping, or the punch member 1004
is broken due to the buckling.
[0013] When the punch member 1004 is exchanged due to any breakage
or the like, it is necessary to perform the operation to scrape the
cured adhesive by using a grinder or the like. However, during this
operation, when the pitch for the punch members 1004 is small, for
example, when the punch members 1004 are arranged at a pitch of not
more than 0.6 mm, then the following inconvenience appears. That
is, for example, a highly sophisticated technique is required for
the operation to detach and attach only the punch member 1004 which
is required to be exchanged. Further, it is complicated to perform
the operation to insert all of the punch members 1004 into the
holes 1006 of the stripper 1005 again.
SUMMARY OF THE INVENTION
[0014] The present invention has been made in order to dissolve the
various problems described above, an object of which is to provide
a punching apparatus for stamping and a method for producing the
same in which the positional accuracy and the shape accuracy of the
hole defined through a workpiece are improved by improving the
positional accuracy of a punch member, the rigidity of the punch
member can be improved, a stripper is prevented from application of
any unbalanced load, and the punch member can be easily
exchanged.
[0015] According to the present invention, there is provided a
punching apparatus for stamping for applying perforating machining
to a workpiece by using punch members, the apparatus comprising a
punch holder secured to an upper die; a die member secured to a
lower die; a plurality of grip members detachably fastened to the
punch holder; and the plurality of punch members formed on each of
the plurality of grip members.
[0016] Accordingly, it is unnecessary to individually assemble the
punch members to the punch holder one by one, and hence there is no
assembling error. Therefore, the positional accuracy of the punch
member is improved, and the positional accuracy and the shape
accuracy can be improved for the hole to be defined through the
workpiece. Further, for example, even when the punch member has a
slender pin-shaped configuration, it is possible to reduce the
occurrence of fracture and breakage, because its rigidity is
enhanced, which is preferred.
[0017] It is preferable for the punching apparatus for stamping
according to the present invention that the grip member and the
punch members are formed in an integrated manner by using a single
material.
[0018] Accordingly, it is unnecessary to separately produce the
grip member and the punch members so that they are assembled to one
another. Therefore, the production steps are simplified, and any
defect does not occur in positional accuracy of the punch member
upon assembling. It is possible to further enhance the rigidity of
the punch member.
[0019] It is preferable for the punching apparatus for stamping
according to the present invention that the grip member has a
rectangular cross section, and a plurality of grooves are formed on
at least two opposing side walls of the rectangular cross section;
and the punch holder is defined with a hole having a rectangular
cross section corresponding to the grip member, and the grip member
is fitted to the punch holder with a gap such that crosspieces
formed between the grooves on the side walls of the grip member
slidably contact with side walls of the hole of the punch holder.
In this arrangement, it is more preferable that the crosspiece on
the side wall of the grip member is formed to have a circular
arc-shaped configuration. It is also preferable that the crosspiece
involves a circular arc-shaped configuration with its top formed to
be flat.
[0020] Accordingly, when the grip member integrally provided with
the punch members is fitted to the hole of the punch holder, a
large amount of adhesive can be contained in the gap between
joining surfaces. The expanding effect of the adhesive is also
exerted after the joining, because the joining surfaces of the grip
member have a large areal size. Thus, it is possible to enhance the
adhesive force between the grip member and the punch holder. The
adhering performance is excellent as compared with the case in
which a flat surface of a grip member is mutually joined to a flat
surface of a punch holder.
[0021] In the punching apparatus for stamping according to the
present invention for applying the perforating processing to the
workpiece by using the punch members, it is preferable that the
grip member is formed by being divided into two or more holding
members, a plurality of grooves having a triangular cross section
are formed on a joining surface of one holding member of the two
holding members to be joined at a dividing surface, and a joining
surface of the other holding member is formed to be flat; each of
the punch members is formed to have a pin-shaped configuration; and
first ends of the plurality of punch members are inserted into
holes defined at the dividing surface.
[0022] Accordingly, the grip members and the punch members can be
easily formed at a high degree of accuracy in an individual
manner.
[0023] According to another aspect of the present invention, there
is provided a method for producing a punching apparatus for
stamping, the method being preferably used and comprising the steps
of using a prism-shaped block as a material for the grip member and
the punch members; machining a plurality of parallel long grooves
separated from each other by arbitrary spacing distances on two
opposing side walls of the prism-shaped block; machining tops of
crosspieces formed between the long grooves to have a circular
arc-shaped configuration; machining long grooves having an
arbitrary depth on another side wall so that the long grooves
communicate with the long grooves on the two side walls;
simultaneously forming thereby the grip member including the
plurality of long grooves and the circular arc-shaped crosspieces
formed between the long grooves provided on the two opposing side
walls and the plurality of punch members each having a lengthy
rectangular cross section with its both ends provided with circular
arc-shaped portions; and defining a plurality of holes each having
a rectangular cross section on the punch holder on the other hand;
wherein the grip member is fitted to the punch holder with a gap
such that the crosspieces formed on the side walls of the grip
member slidably contact with side walls of the hole of the punch
holder.
[0024] In this arrangement, it is also preferable that the circular
arc-shaped top of the crosspiece formed on the side wall of the
grip member and the circular arc-shaped portion at both ends of the
punch member are deformed to include flat portions. It is also
allowable to omit the step of machining and forming the plurality
of parallel long grooves on the side walls of the prism-shaped
block by machining and forming the plurality of parallel circular
arc-shaped crosspieces on the side walls of the prism-shaped block
(see FIG. 7B).
[0025] Accordingly, it is possible to further simplify the
operation steps for integrally producing the grip members and the
punch members, which is preferred.
[0026] The above and other objects, features, and advantages of the
present invention will become more apparent from the following
description when taken in conjunction with the accompanying
drawings in which a preferred embodiment of the present invention
is shown by way of illustrative example.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 shows a longitudinal sectional view illustrating a
punching apparatus for stamping according to a first embodiment of
the present invention;
[0028] FIG. 2 shows an exploded perspective view illustrating a
lower die of the punching apparatus for stamping shown in FIG.
1;
[0029] FIG. 3 shows an exploded perspective view illustrating an
upper die of the punching apparatus for stamping shown in FIG.
1;
[0030] FIG. 4 shows a perspective view illustrating a stamping
punch used for the punching apparatus for stamping shown in FIG.
1;
[0031] FIG. 5 shows a perspective view illustrating a first
modified embodiment of the stamping punch;
[0032] FIG. 6 shows a perspective view illustrating a second
modified embodiment of the stamping punch;
[0033] FIG. 7A shows a step of machining a material to form a
rectangular parallelepiped shaped object;
[0034] FIG. 7B shows a step of machining the rectangular
parallelepiped shaped object to form long grooves on its side
walls;
[0035] FIG. 7C shows a step of machining projections between the
long grooves to form circular arc-shaped crosspieces;
[0036] FIG. 7D shows a step of finally forming a grip member and
punch members in an integrated manner;
[0037] FIG. 8 shows a plan view as viewed from a side of the
stamping punch in order to explain a fitting state of the stamping
punch and the punch holder according to the first embodiment of the
present invention;
[0038] FIG. 9 shows a plan view as viewed from a side of the
stamping punch in order to explain a fitting state of the stamping
punch and the punch holder according to a modified embodiment of
the first embodiment of the present invention;
[0039] FIG. 10 shows a partial magnified sectional view
illustrating a state in which a stripper abuts against a sheet
material, depicting the method for using the punching apparatus for
stamping shown in FIG. 1;
[0040] FIG. 11 shows a partial magnified sectional view
illustrating a state in which the sheet material is subjected to
perforating machining, depicting the method for using the punching
apparatus for stamping shown in FIG. 1;
[0041] FIG. 12 shows a perspective view illustrating a stamping
punch and a fixing jig for punch members used for a punching
apparatus for stamping according to a second embodiment of the
present invention;
[0042] FIG. 13 shows a partial magnified plan view illustrating the
stamping punch and the fixing jig shown in FIG. 12;
[0043] FIG. 14A shows a partial magnified schematic longitudinal
sectional view illustrating a state in which holes are formed
through a punch holder;
[0044] FIG. 14B shows a partial magnified schematic sectional view
illustrating a state in which the holes are finished by means of
wire electric discharge machining; and
[0045] FIG. 15 shows a partial magnified schematic longitudinal
sectional view illustrating a stamping punch concerning the
conventional technique.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0046] The punching apparatus for stamping according to the present
invention will be exemplified by preferred embodiments in relation
to the production method thereof, and it will be explained in
detail below with reference to the accompanying drawings.
[0047] With reference to FIG. 1, reference numeral 10 indicates a
punching apparatus for stamping according to the first embodiment
of the present invention. As shown in FIGS. 1 and 2, the stamping
punching apparatus 10 includes a lower die attachment member 12.
Holes 14a to 14d are defined through the lower die attachment
member 12. Holes 16 are defined at the inside of the holes 14a to
14d. A plate-shaped lower die 18 is secured to an upper portion of
the lower die attachment member 12. Holes 20a to 20d, which have
the same diameter as that of the holes 14a to 14d and which
coaxially communicate with the holes 14a to 14d, are defined
through the lower die 18. Holes 24 having steps 22 are defined at
the inside of the holes 20a to 20d so that they communicate with
the holes 16. Main posts 26a to 26d, which extend upwardly, are
provided in an upstanding manner in the vicinity of the corners of
the lower die 18.
[0048] A plate-shaped die-fixing plate 28 is secured to an upper
portion of the lower die 18. Holes 30a to 30d, which have the same
diameter as that of the holes 20a to 20d and which coaxially
communicate with the holes 20a to 20d, are defined in the vicinity
of the corners of the die-fixing plate 28. A recess 32 is defined
at an upper portion of the die-fixing plate 28. Holes 34, which
communicate with the holes 24, are defined through the bottom for
forming the recess 32. A plurality of die members 36, which are
formed to have a rectangular parallelepiped-shaped configuration,
are fitted to the recess 32 (see FIG. 2). The die member 36 is
secured to the die-fixing plate 28 by using screws 38. A plurality
of lengthy holes 40, which correspond to lengthy holes to be
defined through a sheet material as a workpiece as described later
on, are defined through each of the die members 36.
[0049] As shown in FIGS. 1 and 3, the stamping punching apparatus
10 is provided with an upper die attachment member 42 which is
capable of making approach and separation with respect to the lower
die attachment member 12. The upper die attachment member 42 is
defined with a plurality of recesses 44 and a plurality of holes 46
formed at the inside of the recesses 44. An upper die 48 is secured
to a lower portion of the upper die attachment member 42. Holes 50,
which have the same diameter as that of the recesses 44 and which
coaxially communicate with the recesses 44, are defined through the
upper die 48. A plurality of holes 54 having steps 52 are defined
to make communication with the holes 46. Main post guides 58a to
58d, which protrude downwardly, are formed in the vicinity of
corners of the upper die 48. The main posts 26a to 26d are inserted
into holes 60a to 60d of the main post guides 58a to 58d.
[0050] A punch holder-fixing plate 62 is secured to a lower portion
of the upper die 48. The punch holder-fixing plate 62 is defined
with holes 64 which communicate with the holes 50 and which have a
diameter smaller than that of the holes 50. Columnar members 66 are
slidably inserted into the hole 64. Flanges 68, which protrude
outwardly, are secured by screws 70 to upper portions of the
columnar members 66. The flanges 68 are displaceable in the axial
direction at the inside of the holes 50. The flanges 68 abut
against the upper surface of the punch holder-fixing plate 62, and
thus the columnar members 66 are prevented from disengagement.
First ends of spring members 72 abut against upper portions of the
flanges 68. Second ends of the spring members 72 abut against
ceilings for forming the recesses 44. Therefore, the columnar
members 66 are urged downwardly by the spring members 72.
[0051] As shown in FIGS. 1 and 3, a rectangular recess 82 is
defined at a lower portion of the punch holder-fixing plate 62.
Holes 84, which communicate with the holes 54, are defined through
the ceiling for forming the recess 82. A plurality of punch holders
86, which are formed to have a rectangular parallelepiped-shaped
configuration, are fitted to the recess 82. The punch holders 86
are secured to the punch holder-fixing plate 62 by using screws 88
inserted into the holes 84.
[0052] As shown in FIG. 4, the punch holder 86 is defined with a
plurality of long holes 90. A stamping punch 92 is inserted and
secured into each of the long holes 90. The stamping punch 92
includes a grip member 94 and punch members 96 which are provided
in an integrated manner. The grip member 94 has a lengthy
rectangular configuration including a plurality of long grooves 93
and circular arc-shaped crosspieces 95 formed between the long
grooves 93 which are formed on side walls in the longitudinal
direction thereof. The punch member 96 has a lengthy rectangular
cross section including circular arc-shaped sections 97 which are
formed at both ends in the longitudinal direction thereof. Each of
the punch members 96 protrudes from the lower surface of the grip
member 94 toward the die member 36.
[0053] In this arrangement, as in the first modified embodiment
shown in FIG. 5, it is also preferable that forward ends of
circular arc-shaped tops of the crosspieces 95, which are indicated
by reference numeral 109 and which are formed on the side walls of
the grip member 94a, are deformed to include flat portions.
Alternatively, as in the second modified embodiment shown in FIG.
6, it is also preferable that the side walls of the grip member 94b
are made flat, and the plurality of punch members 96b have a
pin-shaped configuration.
[0054] When the length of protrusion of the punch member 96 from
the grip member 94 is formed to be short, then the rigidity of the
punch member 96 is improved to decrease the fear of deformation and
buckling of the punch member 96. On the other hand, when the length
is formed to be long, then it is possible to increase the number of
grinding operations performed to use the worn punch member 96
again, and thus the service life of the punch member 96 is
prolonged.
[0055] As shown in FIGS. 1 and 3, a stripper-fixing plate 98 is
arranged under the punch holder-fixing plate 62. The upper surface
of the stripper-fixing plate 98 is fixed to the columnar members 66
by using screws 100. Subposts 102a to 102d, which penetrate through
holes 103 disposed in the vicinity of corners of the
stripper-fixing plate 98 and which extend downwardly, are provided
at lower portions of the punch holder-fixing plate 62. Therefore,
the stripper-fixing plate 98 is supported such that it is capable
of making approach and separation with respect to the punch
holder-fixing plate 62. As shown in FIG. 1, the lower portions of
the subposts 102a to 102d are slidably inserted into the holes 14a
to 14d, 20a to 20d, 30a to 30d. Accordingly, when the upper die 48
makes the displacement in the direction to make approach or
separation with respect to the lower die 18, the lower die 18 and
the upper die 48 are prevented from positional deviation by the aid
of the main posts 26a to 26d and the subposts 102a to 102d.
[0056] A recess 104 is defined at a lower portion of the
stripper-fixing plate 98. A plurality of strippers 106, which are
formed to have a rectangular parallelepiped-shaped configuration,
are fitted to the walls 105 for forming the recess 104. The
stripper 106 is secured to the stripper-fixing plate 98 by using
screws 108. A plurality of long holes 110, through which the punch
members 96 are slidably inserted, are defined through the stripper
106. A recess 111 for advancing an unillustrated machining tool is
defined on the upper surface of the stripper 106 in order to
facilitate the perforating machining for the long holes 110.
[0057] The stamping punching apparatus 10 according to the first
embodiment of the present invention is basically constructed as
described above. Next, its production process will be
explained.
[0058] At first, explanation will be made with reference to FIGS.
7A to 7D for the method for producing the grip member 94 and the
punch members 96.
[0059] As shown in FIG. 7A, a material such as a general cemented
carbide material is subjected to surface grinding machining for six
surfaces by using an unillustrated surface grinding machine to form
a lengthy rectangular parallelepiped shaped configuration 99.
Subsequently, as shown in FIG. 7B, long grooves 101 having a
rectangular cross section are formed on two opposing side walls of
the rectangular parallelepiped shaped configuration 99. Further, as
shown in FIG. 7C, projections between the long grooves 101 on the
side walls are formed into crosspieces 95 having a circular
arc-shaped cross section by using an unillustrated numerical
control machine tool.
[0060] Further, as shown in FIG. 7D, long grooves 107 having a
predetermined depth are formed on another side wall so that the
long grooves 107 communicate with the long grooves 101 on the two
side walls described above. Accordingly, the grip member 94
including the plurality of long grooves 93 and the crosspieces 95
formed between the long grooves 93 on the two side walls, and the
plurality of punch members 96 having a lengthy rectangular cross
section with the circular arc-shaped section 97 formed at the both
ends are formed in an integrated manner.
[0061] Conventionally, the stamping punch has been formed by using
an ultra-fine grain cemented carbide material which is provided
with a high hardness as well as a high toughness, and it is
produced by performing grinding by using a grinding stone or the
like to form a punch member 96. However, in the case of a soft
workpiece such as a green sheet, the stamping load is small, and
little wear occurs. Therefore, as described in the embodiment of
the present invention, the perforating machining can be applied by
using the stamping punch 92 which is formed by processing the
general cemented carbide material by means of the electric
discharge machining.
[0062] In this process, the grip member 94 and the punch members 96
are formed in the integrated manner. Therefore, the production
steps for the stamping punch 92 can be simplified. Further, the
rectangular parallelepiped shaped configuration 99, which has aflat
surface with a high machining accuracy, is formed by using the
surface grinding machine. Furthermore, the circular arc-shaped
crosspieces 95, which has a high machining accuracy, are formed on
the side walls of the grip member 94 by using the NC machining
machine. In this process, it is also preferable that the crosspiece
95 having the circular arc-shaped configuration with a flat top
according to the first modified embodiment shown in FIG. 5 is
formed by performing grinding by using the NC machining machine
while partially leaving the flat portion formed by surface grinding
machining, in place of the crosspiece 95 between the long grooves
93 on the side wall formed to have the circular arc-shaped cross
section by using the NC machining machine. The partially remaining
flat portion has been previously formed by means of surface
grinding machining in which the accuracy can be easily obtained.
Therefore, it is possible to obtain the high flatness as compared
with the formation performed by using the NC machining machine.
[0063] During the production process, an intermediate inspection is
performed to confirm the fitting accuracy by inserting the stamping
punch 92 into the long hole 90 of the punch holder 86 (see FIG. 4)
at the stage at which surface grinding machining is applied to the
six surfaces of the material (see FIG. 7A) and at the stage at
which the long grooves 101 are formed on the side walls of the
rectangular parallelepiped shaped material 99 (see FIG. 7B)
respectively. If any defect in fitting accuracy is confirmed in the
intermediate inspection, the machining is performed again for the
purpose of repair. Therefore, a defective shaped is prevented
without any subsequent production steps being carried out in
vain.
[0064] On the other hand, when the punch members 96b having the
pin-shaped configuration according to the second embodiment shown
in FIG. 6 are formed, the punch members 96b having the narrow
spacing distance or having the small diameter can be highly
accurately produced by applying, for example, the wire electric
discharge machining.
[0065] The stamping punch 92 thus produced is inserted and fitted
into the long hole 90 of the punch holder 86, and the portion of
the grip member 94 is secured by using an adhesive or the like.
[0066] In this process, if the grip member 94, which is joined to
the side walls of the long hole 90 of the punch holder 86, has a
flat surface over its side walls, it is necessary to increase the
machining accuracy in order to increase the fitting accuracy. On
this condition, even if the fitting accuracy is increased, the
adhesive merely enters the minute gap between the joined surfaces.
As a result, the adhesive strength is defective, and it is
impossible to obtain any good fitted state. For example, problems
arise in that the adhered portion is peeled off during the punching
process described later on, and the stamping punch 92 is
disengaged. In such a circumstance, it may be conceived that
forcible insertion or shrinkage fitting is performed upon the
fitting. However, such a procedure is not preferred because the
stress generated thereby remains and strain is caused.
[0067] On the contrary, as in the first embodiment of the present
invention shown in FIG. 8 and the first modified embodiment shown
in FIG. 9, a sufficient gap 113 is provided for the joined surfaces
when the fitting is performed. Accordingly, a large amount of
adhesive can be contained in the space of the gap 113. Further, the
expanding effect of the adhesive after the joining is also added,
because the areal size of the joined surfaces is large on the side
of the grip member 94. Thus, it is possible to obtain a large
adhesive force.
[0068] In this state, the linear portion indicated by reference
numeral 115 in FIG. 8, or the flat portion indicated by reference
numeral 109 in FIG. 9, which is formed and machined highly
accurately by means of the surface grinding machining for the six
surfaces, remains at the top of the crosspiece 95 of the side wall
of the grip member 95. These portions slidably make line-to-line or
surface-to-surface contact with the side walls of the long hole of
the punch holder 86. Therefore, the fitting accuracy is
excellent.
[0069] Subsequently, as shown in FIG. 3, the punch holders 86 are
installed to the recess 82 of the punch holder-fixing plate 62, and
they are secured by using the screws 88. As shown in FIG. 1, the
punch members 96 are inserted into the holes 110 of the stripper
106, and the stripper 106 is secured to the stripper-fixing plate
98 by using the screws 108.
[0070] Next, explanation will be made for the operation of the
stamping punching apparatus constructed as described above,
especially for the operation effected when the stamping punching
apparatus 92 according to the second modified embodiment (see FIG.
6) is used. At first, as shown in FIG. 1, a sheet material 120 such
as a ceramic green sheet is placed on the die members 36.
[0071] Subsequently, when the upper die attachment member 42 is
moved downwardly in accordance with the action of an unillustrated
driving source, the lower surface of the stripper 106 abuts against
the upper surface of the sheet material 120 as shown in FIG. 10.
The sheet material 120 is pressed against the stripper 106 by the
aid of the resilient force of the spring member 72 shown in FIG. 1.
Accordingly, the sheet material 120 is positioned, and it is
prevented from positional deviation.
[0072] When the upper die attachment member 42 is further moved
downwardly, the spring member 72 is contracted. As shown in FIG.
11, the forward ends of the punch members 96 protrude from the
holes 110 of the stripper 106. Thus, long holes 122 are defined
through the sheet material 120.
[0073] In the present invention, the punch members 96 are formed
integrally with the grip members 94, and the grip members 94 are
fitted to the punch holders 86 at a high degree of accuracy.
Therefore, the positional accuracy of the punch member is improved.
Accordingly, the positional accuracy and the shape accuracy of the
long holes 122 defined through the sheet material 120 are improved.
Further, the space between the hole 122 and the adjoining hole 122
of the sheet material 120 is appropriately supported by the die
member 36. Accordingly, the sheet material 120 is prevented from
inclination and breakage. Further, the rigidity of the punch member
is also improved, and hence no unbalanced load is exerted on the
stripper.
[0074] Subsequently, when the unillustrated driving source is
energized in an opposite direction, then the upper die attachment
member 42 is moved upwardly, and the punch members 96 and the
stripper 106 are separated from the sheet material 120. Thus, the
sheet material 120 subjected to the perforating machining is
obtained.
[0075] When the punch member 96 is broken or worn, and it is
required to be exchanged, then the stamping punch 92 including the
punch member 96 required to be exchanged is detached from the long
hole 90 of the punch holder 86. Subsequently, a grip member 94 of a
stamping punch 94 for exchange is inserted and secured into the
long hole 90. The punch member 96 is inserted into the hole 110 of
the stripper 106. The punch members 96 are easily inserted into the
holes 110, because the respective punch members 96 have the high
positional accuracy.
[0076] Next, a stamping punching apparatus according to the second
embodiment of the present invention will be explained in relation
to the production process thereof. Explanation will be made below
for components or parts different from those of the stamping
punching apparatus 10 according to the first embodiment. The same
components or parts as those of the first embodiment are designated
by the same reference numerals in the drawings, detailed
explanation of which will be omitted.
[0077] As shown in FIG. 12, in this embodiment, the stamping punch
92c is formed by the grip member 94c divided into a plurality of
components so that the punch members 96c are interposed thereby.
That is, the grip member 94c is constructed separately from the
punch members 96c in this embodiment. The grip member 94c used in
this embodiment comprises a first holding member 114 which is
disposed at the center of the grip member 94c and which is formed
to have a lengthy configuration. Both side portions of the first
holding member 114, which are disposed along the longitudinal
direction, are formed as flat sections 115a, 115b.
[0078] A pair of second holding members 116a, 116b, which are
formed to have a lengthy configuration, are arranged for the
respective flat sections 115a, 115b. A plurality of grooves 124 are
defined in parallel to one another in a direction perpendicular to
the longitudinal direction of the second holding member 116a, 116b,
on the lengthy wall surface of the second holding member 116a,
116b. The groove 124 is formed to have a substantially V-shaped
configuration.
[0079] A recess 117 is defined on the bottom of the first holding
member 114. On the other hand, recesses 118a, 118b are defined on
the second holding members 116a, 116b. A chamber 123 is formed by
the recess 117 and the recesses 118a, 118b.
[0080] When a plurality of punch members 96c are secured to the
grip member 94c formed as described above, a fixing jig 130 is
used. The fixing jig 130 comprises a first jig 132 which is placed
on an upper portion of the first holding member 114 and which is
formed to have a rectangular parallelepiped-shaped configuration,
and second jigs 134a, 134b which are placed on upper portions of
the second holding members 116a, 116b and which are defined with
grooves 136 each having a V-shaped cross section communicating with
the grooves 124. Bar members 135a, 135b for gripping the first jig
132 are secured to upper portions of the first jig 132.
[0081] When the plurality of punch members 96c are secured to the
grip member 94c, the first jig 132 is firstly placed on the upper
portion of the first holding member 114. In this state, the first
holding member 114 is separated from the second holding members
116a, 116b. Subsequently, when the second jigs 134a, 134b are
placed on the second holding members 116a, 116b, the grooves 124
communicate with the grooves 136. Subsequently, the punch members
96c are arranged in the grooves 124 and the grooves 136.
[0082] The first holding member 114 is interposed by the second
holding members 116a, 116b, and the first jig 132 is interposed by
the second jigs 134a, 134b. Accordingly, as shown in FIG. 13, the
plurality of punch members 96c are positioned in parallel to one
another by being interposed by the walls for forming the grooves
124, 136 and the walls of the first holding member 114 and the
second jigs 134a, 134b.
[0083] In this state, the punch members 96c are interposed by the
walls for forming the grooves 124, 136 and the walls of the first
holding member 114 and the second jigs 134a, 134b, and they are
positioned with a high positional accuracy. As shown in FIG. 12, an
adhesive is charged into the chamber 123. When the adhesive is
cured, the punch members 96c are secured highly accurately by the
first holding member 114 and the second holding members 116a, 116b.
Thus, the stamping punch 92 is produced.
[0084] When the stamping punch 92c is produced as described above,
the punch members 96c can be highly accurately secured to the punch
holder 86, for example, even in the case of a minute punch in which
the punch member 96c has a diameter of not more than 0.3 mm. The
plurality of punch members 96c are aligned on one grip member 94c.
Therefore, it is possible to arbitrarily select the number of
stamping punches 92c necessary for one stamping punching
apparatus.
[0085] Subsequently, as shown in FIG. 4, the stamping punch 92 is
inserted into the long hole 90 of the punch holder 86 in the same
manner as in the first embodiment (the other constitutive
components except for the stamping punch 92 and the punch holder 86
of the second embodiment are the same as those of the first
embodiment, and explanation will be made below by using the
drawings and reference numerals described in the first
embodiment).
[0086] As shown in FIG. 3, the punch holders 86 are installed to
the recess 82 of the punch holder-fixing plate 62, and they are
secured by using the screws 88. Subsequently, as shown in FIG. 1,
the punch members 96 are inserted into the holes 110 of the
stripper 106. The stripper 106 is secured to the stripper-fixing
plate 98 by using the screws 108. Thus, the stamping punching
apparatus is obtained.
[0087] In the stamping punching apparatus according to the second
embodiment described above, the punch member 96 is formed to have
the circular cross section. However, other configurations are
available, including, for example, oblong or elliptic
configurations. Further, the grip member 94 may be formed to
connect the plurality of punch members 96.
* * * * *