U.S. patent application number 10/107307 was filed with the patent office on 2002-12-05 for robot hand member and method of producing the same.
Invention is credited to Aoyagi, Kenichi, Kobayashi, Takashi, Uchida, Daisuke.
Application Number | 20020180104 10/107307 |
Document ID | / |
Family ID | 27346409 |
Filed Date | 2002-12-05 |
United States Patent
Application |
20020180104 |
Kind Code |
A1 |
Kobayashi, Takashi ; et
al. |
December 5, 2002 |
Robot hand member and method of producing the same
Abstract
A robot hand member mounted on an arm unit of an industrial
robot and a method of producing the same, wherein there are
successively executed a step of laminating prepreg sheets each
containing a reinforcing fiber on the outer peripheral surface of a
core member having a predetermined shape in cross section, a step
of heating the laminated prepreg sheets to a predetermined
temperature to thermally set, to form a fiber reinforced plastic,
and a step of removing the core member from the fiber reinforced
plastic to obtain a hollow structure.
Inventors: |
Kobayashi, Takashi;
(Yokohama, JP) ; Aoyagi, Kenichi; (Yokohama,
JP) ; Uchida, Daisuke; (Tokyo, JP) |
Correspondence
Address: |
Finnegan, Henderson, Farabow,
Garrett & Dunner, L.L.P.
1300 I Street, N.W.
Washington
DC
20005-3315
US
|
Family ID: |
27346409 |
Appl. No.: |
10/107307 |
Filed: |
March 28, 2002 |
Current U.S.
Class: |
264/258 ;
264/313 |
Current CPC
Class: |
B29L 2022/00 20130101;
B29C 70/345 20130101 |
Class at
Publication: |
264/258 ;
264/313 |
International
Class: |
B29C 070/42 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 29, 2001 |
JP |
2001-97478 |
Mar 29, 2001 |
JP |
2001-97479 |
Apr 13, 2001 |
JP |
2001-115215 |
Claims
What is claimed is:
1. A robot hand member, which is mounted on an arm unit of an
industrial robot, has a predetermined shape in cross section, and
extends in a longitudinal direction, wherein prepreg sheet each
containing a reinforcing fiber are laminated on the outer
peripheral surface of a core member, said laminated prepreg sheets
are heated to a predetermined temperature to be thermally set, to
form a fiber reinforced plastic, and then, the core member is
removed from said fiber reinforced plastic.
2. A method of producing a robot hand member which is mounted on an
arm unit of an industrial robot, comprising the steps to be
sequentially executed of: winding prepreg sheets each containing a
reinforcing fiber on the outer peripheral surface of a core member
that is in a predetermined shape in cross section and is made of
material that is not deformed by the heating at temperatures equal
to or lower than a predetermined temperature; molding the outer
surface shape of said wound prepreg sheets into a predetermined
size by pushing an outer mold having a predetermined inner surface
shape onto the outer peripheral surface of said wound prepreg
sheets; heating said molded prepreg sheets to the predetermined
temperature to thermally set the heated prepreg sheets, to form a
fiber reinforced plastic; and removing the core member from said
fiber reinforced plastic to form a hollow structure.
3. A method of producing a robot hand member according to claim 2,
wherein said step of winding prepreg sheets on the outer peripheral
surface of a core member winds the prepreg sheets in a
multi-layer.
4. A method of producing a robot hand member according to claim 3,
wherein said step of winding prepreg sheets in a multi-layer
includes a step of laminating prepreg sheets in a manner that
reinforcing fibers therein are oriented differently to each other
in a direction along the longitudinal direction and in a direction
nearly at a right angle with the longitudinal direction.
5. A method of producing a robot hand member according to claim 2,
further comprising a step of winding a cloth prepreg sheet on the
outermost layer on which the prepreg sheets are wound.
6. A method of producing a robot hand member which is mounted on an
arm unit of an industrial robot, comprising the steps to be
sequentially executed of: dividing, into a plurality of regions,
the outer peripheral surface of a core member that is in a
predetermined shape in cross section and is not deformed by the
heating at temperatures equal to or lower than a predetermined
temperature and adhering prepreg sheets each containing a
reinforcing fiber onto each of said divided regions; heating the
core member onto which the prepreg sheets are adhered, to the
predetermined temperature, to thermally set the member, to form a
fiber reinforced plastic; and removing the core member from said
fiber reinforced plastic to form a hollow structure.
7. A method of producing a robot hand member according to claim 6,
wherein said step of dividing, into a plurality of regions, the
outer peripheral surface of a core member and adhering prepreg
sheets adheres the prepreg sheets in a multi-layer.
8. A method of producing a robot hand member according to claim 7,
wherein said step of adhering prepreg sheets in a multi-layer
includes a step of laminating prepreg sheets in a manner that
reinforcing fibers therein are oriented differently to each other
in a direction along the longitudinal direction and in a direction
nearly at a right angle with the longitudinal direction.
9. A method of producing a robot hand member according to claim 6,
further comprising a step of winding a cloth prepreg sheet on the
outermost layer onto which the prepreg sheets are adhered, to cover
said member onto which the prepreg sheets are adhered.
10. A robot hand member, which is mounted on an arm unit of an
industrial robot, has a predetermined shape in cross section, and
extends in a longitudinal direction, wherein prepreg sheets each
containing a reinforcing fiber are laminated on the whole of or a
part of the outer peripheral surface of a core member, the core
member laminated with the prepreg sheets are heated to a
predetermined temperature to be thermally set, to form a fiber
reinforced plastic that is integrated with the core member.
11. A method of producing a robot hand member which is mounted on
an arm unit of an industrial robot, comprising the steps to be
sequentially executed of: winding prepreg sheets each containing a
reinforcing fiber on the outer peripheral surface of a core member
that is in a predetermined shape in cross section and is made of
material that is not deformed by the heating at temperatures equal
to or lower than a predetermined temperature; molding the outer
surface shape of said wound prepreg sheets into a predetermined
size by pushing an outer mold having a predetermined inner surface
shape onto the outer peripheral surface of said wound prepreg
sheets; and heating said molded prepreg sheets to the predetermined
temperature to thermally set the heated prepreg sheets, to form a
fiber reinforced plastic integrated with the core member.
12. A method of producing a robot hand member according to claim
11, wherein said step of winding prepreg sheets on the outer
peripheral surface of a core member winds the prepreg sheets in a
multi-layer.
13. A method of producing a robot hand member according to claim
12, wherein said step of winding prepreg sheets in a multi-layer
includes a step of laminating prepreg sheets in a manner that
reinforcing fibers therein are oriented differently to each other
in a direction along the longitudinal direction and in a direction
nearly at a right angle with the longitudinal direction.
14. A method of producing a robot hand member according to claim
11, further comprising a step of winding a cloth prepreg sheet on
the outermost layer on which the prepreg sheets are wound.
15. A method of producing a robot hand member which is mounted on
an arm unit of an industrial robot, comprising the steps to be
sequentially executed of: dividing, into a plurality of regions,
the outer peripheral surface of a core member that is in ;a
predetermined shape in cross section and is not deformed by the
heating at temperatures equal to or lower than a predetermined
temperature and adhering prepreg sheets each containing a
reinforcing fiber onto at least one of said divided regions; and
heating the core member onto which the prepreg sheets are adhered,
to the predetermined temperature, to thermally set the member, to
form a fiber reinforced plastic.
16. A method of producing a robot hand member according to claim
15, wherein said step of dividing, into a plurality of regions, the
outer peripheral surface of a core member and adhering prepreg
sheets onto at least one of said divided regions adheres the
prepreg sheets in a multi-layer.
17. A method of producing a robot hand member according to claim
16, wherein said step of adhering the prepreg sheets in a
multi-layer includes a step of laminating prepreg sheets in a
manner that reinforcing fibers therein are oriented differently to
each other in a direction along the longitudinal direction and in a
direction nearly at a right angle with the longitudinal
direction.
18. A method of producing a robot hand member according to claim
15, further comprising a step of winding a cloth prepreg sheet on
the outermost layer onto which the prepreg sheets are adhered, to
cover said member onto which the prepreg sheets are adhered.
19. A method of producing a robot hand member which is mounted on
an arm unit of an industrial robot, comprising the steps to be
sequentially executed of: dividing, into a plurality of regions,
the outer peripheral surface of a core member that is in a
predetermined shape in cross section and is not deformed by the
heating at temperatures equal to or lower than a predetermined
temperature and adhering prepreg sheets each containing a
reinforcing fiber onto each of said divided regions; and heating
the core member onto which the prepreg sheets are adhered, to the
predetermined temperature, to thermally set the member, to form a
fiber reinforced plastic.
20. A method of producing a robot hand member according to claim
19, wherein said step of dividing, into a plurality of regions, the
outer peripheral surface of a core member and adhering prepreg
sheets adheres the prepreg sheets in a multi-layer.
21. A method of producing a robot hand member according to claim
20, wherein said step of adhering the prepreg sheets in a
multi-layer includes a step of laminating prepreg sheets in a
manner that reinforcing fibers therein are oriented differently to
each other in a direction along the longitudinal direction and in a
direction nearly at a right angle with the longitudinal
direction.
22. A method of producing a robot hand member according to claim
19, further comprising a step of winding a cloth prepreg sheet on
the outermost layer onto which the prepreg sheets are adhered, to
cover said member onto which the prepreg sheets are adhered.
23. A robot hand member, which is mounted on an arm unit of an
industrial robot and is made of fiber reinforced plastic, wherein
said robot hand member is formed in a hollow rectangular shape in
transverse cross section and is formed with, in an inner space of a
constituent member extending in a longitudinal direction, at least
one rib that extends across the long sides opposing to each other
in the transverse cross section, and also extends in a longitudinal
direction of the inner space.
24. A method of producing a robot hand member which is mounted on
an arm unit of an industrial robot, comprising the steps to be
sequentially executed of: arranging core members each of which has
a rectangular shape in transverse cross section and is not deformed
by the heating at temperatures equal to or lower than a
predetermined temperature, on both side surfaces of a
rib-constituting member formed in a rectangular shape in transverse
cross section and containing a reinforcing fiber, to form a
composite structure having a rectangular shape in cross section as
a whole; laminating prepreg sheets each containing a reinforcing
fiber in a predetermined thickness on the outer peripheral surface
of said composite structure; heating said composite structure on
which the prepreg sheets are laminated to the predetermined
temperature, to form a fiber reinforced plastic in which said
rib-constituting member and the prepreg sheets are integrated; and
removing the core members from the fiber reinforced plastic.
25. A method of producing a robot hand member according to claim
24, wherein said step of laminating prepreg sheets in a
predetermined thickness adheres to laminate prepreg sheets formed
to meet the shape of the surface of the composite structure or the
shapes of the surfaces of the core members on the surface of the
composite structure or the surfaces of the core members.
26. A method of producing a robot hand member according to claim
24, wherein said step of laminating prepreg sheets in a
predetermined thickness winds to laminate the prepreg sheets on the
outer peripheral surface of the composite structure or the outer
peripheral surfaces of the core members.
27. A method of producing a robot hand member according to claim
24, wherein said step of laminating prepreg sheets in a
predetermined thickness includes a step of laminating prepreg
sheets in a manner that reinforcing fibers therein are oriented
differently to each other in a direction along the longitudinal
direction and in a direction nearly at a right angle with the
longitudinal direction.
28. A method of producing a robot hand member according to claim
24, further comprising a step of winding a cloth prepreg sheet on
the outer peripheral surface of the composite structure on which
the prepreg sheets are laminated, to cover said composite
structure.
29. A method of producing a robot hand member which is mounted on
an arm unit of an industrial robot, comprising the steps to be
sequentially executed of: laminating prepreg sheets each containing
a reinforcing fiber in a predetermined thickness on the outer
peripheral surfaces of core members each of which has a rectangular
shape in transverse cross section and is not deformed by the
heating at temperatures equal to or lower than a predetermined
temperature; bringing the plurality of core members on which the
prepreg sheets are laminated, respectively, into contact with one
another on their side surfaces, to form a composite structure
having a rectangular shape in cross section as a whole; laminating
prepreg sheets each containing a reinforcing fiber in a
predetermined thickness on the outer peripheral surface of said
composite structure; heating said composite structure on which the
prepreg sheets are laminated to the predetermined temperature, to
form a fiber reinforced plastic in which the prepreg sheets
laminated on said core members and the prepreg sheets laminated on
said composite structure are integrated; and removing said core
members from said fiber reinforced plastic.
30. A method of producing a robot hand member according to claim
29, wherein said step of laminating prepreg sheets in a
predetermined thickness adheres to laminate prepreg sheets formed
to meet the shape of the surface of the composite structure or the
shapes of the surfaces of the core members on the surface of the
composite structure or the surfaces of the core members.
31. A method of producing a robot hand member according to claim
29, wherein said step of laminating prepreg sheets in a
predetermined thickness winds to laminate the prepreg sheets on the
outer peripheral surface of the composite structure or the outer
peripheral surfaces of the core members.
32. A method of producing a robot hand member according to claim
29, wherein said step of laminating prepreg sheets in a
predetermined thickness includes a step of laminating prepreg
sheets in a manner that reinforcing fibers therein are oriented
differently to each other in a direction along the longitudinal
direction and in a direction nearly at a right angle with the
longitudinal direction.
33. A method of producing a robot hand member according to claim
29, further comprising a step of winding a cloth prepreg sheet on
the outer peripheral surface of said composite structure on which
the prepreg sheets are laminated, to cover said composite
structure.
34. A method of producing a robot hand member which is mounted on
an arm unit of an industrial robot, comprising the steps to be
sequentially executed of: bringing a plurality of unit constituent
members each having a hollow rectangular shape in transverse cross
section and containing a reinforcing fiber into contact with one
another on their side surfaces, to form a composite structure
having a rectangular shape in cross section as a whole; adhering
prepreg sheets each containing a reinforcing fiber over the side
surfaces on the same sides intersecting the contacting surfaces of
said composite structure; and heating said composite structure onto
which the prepreg sheets are adhered, to a predetermined
temperature, to form a fiber reinforced plastic in which said unit
constituent members and the prepreg sheets are integrated.
35. A method of producing a robot hand member according to claim
34, wherein said step of adhering prepreg sheets winds to adhere
prepreg sheets onto the outer peripheral surface of said composite
member.
36. A method of producing a robot hand member according to claim
34, wherein said step of adhering prepreg sheets adheres the
prepreg sheets in a multi-layer.
37. A method of producing a robot hand member according to claim
34, wherein said step of adhering prepreg sheets in a multi-layer
includes a step of laminating prepreg sheets in a manner that
reinforcing fibers therein are oriented differently to each other
in a direction along the longitudinal direction and in a direction
nearly at a right angle with the longitudinal direction.
38. A method of producing a robot hand member according to claim
34, further comprising a step of winding a cloth prepreg sheet on
the outer peripheral surface of said composite structure onto which
the prepreg sheets are adhered, to cover said composite structure.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a robot hand member to be
mounted on an arm unit of an industrial robot and to a method of
producing the same. More specifically, the invention relates to a
robot hand member made of fiber reinforced plastic obtained by
thermally setting a prepreg sheet containing a reinforcing fiber
laminated on the outer peripheral surface of a core member, and to
a method of producing the same.
[0003] 2. Description of the Related Art
[0004] Glass substrates that have been produced in increased sizes
accompanying a widespread use of liquid crystal displays (LCDs),
have required an increase in size of a substrate-conveyer robot
hand to be used in the production process of precision parts such
as LCDs, plasma display panels (PDPs), silicon wafers and the like.
Further, a robot hand for conveying large plasma display panels
(PDPs) has a size larger than that of the robot hand for conveying
the LCDs.
[0005] Metals such as steel, stainless steel and aluminum have
heretofore been used as materials of robot hands. Accompanying an
increase in size of the robot hands in recent years, however, it is
a trend to use fiber reinforced plastics (hereinafter abbreviated
as "FRPs"). In particular, there has been widely used a robot hand
member made of solid member of a carbon fiber reinforced
(hereinafter abbreviated as "CFRP").
[0006] At the present time where the size is ever increasing,
however, the solid member of CFRP causes the robot hand itself to
become heavy resulting in an increased deflection due to its own
weight. Further, as the robot hand becomes heavy, a load on a robot
drive system is increased, thereby affecting the design of the
robot and the cost thereof. The deflection due to its own weight
can be decreased to some extent by decreasing the weight, i.e., by
decreasing the thickness of the robot hand member or by decreasing
the width of a support surface. With this countermeasure, however,
since the flexural rigidity of the robot hand is lowered, the
deflection (deflection due to the load) is increased at the time of
supporting the workpiece. When a long robot hand member is
cantilevered, in particular, deflection at an end thereof is
increased, and vibration is increased when the workpiece is
supported, causing a trouble in supporting or conveying the
workpiece.
[0007] As disclosed in Japanese Unexamined Patent Publication No.
2000-343476, there has been proposed a technology of producing a
robot hand by separately forming a skin layer of a plate-like
carbon fiber reinforced plastic (CFRP) obtained by heating to
thermally set a laminate of a plurality of prepreg sheets each
containing a carbon fiber, and a core layer similarly made of the
CFRP, laminating the skin layers on the upper surface and on the
lower surface of the core layer which serves as a core member, and
adhering together the core layer and the skin layer with an
adhesive.
[0008] As the skin layer, in this case, a plurality of prepreg
sheets containing carbon fibers oriented in different directions
are laminated one upon another, to improve the flexural rigidity,
vibration attenuation characteristics and heat resistance. As the
core layer, further, a CFRP member and a honeycomb core member made
of metal such as aluminum and an aggregate of fibers, are combined
with each other, to improve the flexural rigidity, vibration
attenuation characteristics and heat resistance while reducing the
weight.
[0009] According to this method, however, since there are once
formed, as materials, the skin layer comprising the CFRP having a
predetermined thickness and a predetermined area, and the core
layer similarly comprising the CFRP, the skin layers are adhered
onto the upper and lower surfaces of the core layer which serves as
a core member with an adhesive, and the thus obtained laminate is
cut into predetermined length and width so as to be worked into a
predetermined shape, an increased number of production processes is
required. Therefore, a period of time required for the production
becomes longer and the cost for the production becomes high.
[0010] There has further been contrived a method of adhering with
an adhesive four CFRP plates each formed in a predetermined
thickness, to form a square pipe. This method, however, requires a
step of laminating prepreg sheets, a step of forming the CFRP
plates by the thermosetting, and a step of adhering the CFRP
plates, and also there is such a problem that the portions where
the CFRP plates are adhered have the low strength against a
load.
[0011] The robot hand member has been designed for conveying, as
the workpieces, precision parts, such as, liquid crystal displays,
plasma display panels, silicon wafers and the like, and is required
to have flatness so as to avoid the scar on such workpieces. If the
robot hand member has a hollow structure, however, the central
portion is likely to be dented.
SUMMARY OF THE INVENTION
[0012] Therefore, it is an object of the present invention to cope
with the above-mentioned problem, and to provide a robot hand
member having the high strength against a load, the low deflection
and a high degree of flatness, requiring a short period of time and
a low cost for production, and a method of producing the same.
[0013] In order to accomplish the above-mentioned object, a robot
hand member according to the present invention, which is mounted on
an arm unit of an industrial robot, has a predetermined shape in
cross section, and extends in a longitudinal direction, is
constituted such that prepreg sheets each containing a reinforcing
fiber are laminated on the outer peripheral surface of a core
member, the laminated prepreg sheets are heated to a predetermined
temperature to be thermally set, to form a fiber reinforced
plastic, and then, the core member is removed from the fiber
reinforced plastic.
[0014] According to the above constitution, it is possible to form
a robot hand member with a small number of production processes and
a low production cost. By using the fiber reinforced plastic,
further, it is possible to produce a robot hand member which is
lighter in weight than the one made of metal, having excellent
flatness, flexural rigidity, vibration attenuation characteristics
and heat resistance. Further, since the core member is removed to
form a hollow structure, it is possible to further improve the
light in weight, and besides, it is possible to arrange, in the
hollow portion, the devices, wirings, pipe arrangement and the like
necessary for the functions of the robot hand. Further, since the
core member can be repetitively used, it is possible to lower the
material cost.
[0015] A method of producing the robot hand member described above
comprises the steps to be sequentially executed of: winding prepreg
sheet each containing a reinforcing fiber on the outer peripheral
surface of a core member that is in a predetermined shape in cross
section and is made of material that is not deformed by the heating
at temperatures equal to or lower than a predetermined temperature;
molding the outer surface shape of the prepreg sheets into a
predetermined size by pushing an outer mold having a predetermined
inner surface shape onto the outer peripheral surface of the wound
prepreg sheets; heating the molded prepreg sheets to the
predetermined temperature to thermally set the heated prepreg
sheets, to form a fiber reinforced plastic; and removing the core
member from the fiber reinforced plastic to form a hollow
structure.
[0016] Further, another method of producing the robot hand member
described above comprises the steps to be sequentially executed of:
dividing, into a plurality of regions, the outer peripheral surface
of a core member that is in a predetermined shape in cross section
and is not deformed by the heating at temperatures equal to or
lower than a predetermined temperature and adhering prepreg sheets
each containing a reinforcing fiber onto each of the divided
regions; heating the core member onto which the prepreg sheets are
adhered, to the predetermined temperature, to thermally set the
member to form a fiber reinforced plastic; and removing the core
member from the fiber reinforced plastic to form a hollow
structure. In this case, since the prepreg sheets are adhered to
each of the regions divided on the outer peripheral surface of the
core member, the corner portions are not swollen toward the outer
side. Therefore, there is no need of using a dedicated outer mold
that meets the outer surface shape of the robot hand member.
[0017] Another robot hand member according to the present
invention, which is mounted on an arm unit of an industrial robot,
has a predetermined shape in cross section, and extends in a
longitudinal direction, is constituted such that prepreg sheets
each containing a reinforcing fiber is laminated on the whole of or
a part of the outer peripheral surface of a core member, the core
member laminated with the prepreg sheets are heated to
a-predetermined temperature to be thermally set, to form a fiber
reinforced plastic that is integrated with the core member.
[0018] According to this constitution, it is possible to form a
robot hand member with a small number of production processes and a
low production cost. By using the fiber reinforced plastic,
further, it is possible to produce a robot hand member which is
lighter in weight and has a less deflection characteristic.
Further, since the core member is left to stay therein to form a
solid structure, the central portion of the robot hand member is
prevented from being dented, thereby improving the flatness. Note,
by using, as a core member, a light-weight member such as a
synthetic resin that is lighter than the fiber reinforced plastic,
it is possible to further decrease the weight.
[0019] A method of producing the robot hand member described above
comprises the steps to be sequentially executed of: winding prepreg
sheets each containing a reinforcing fiber on the outer peripheral
surface of a core member that is in a predetermined shape in cross
section and is made of material that is not deformed by the heating
at temperatures equal to or lower than a predetermined temperature;
molding the outer surface shape of the prepreg sheets into a
predetermined size by pushing an outer mold having a predetermined
inner surface shape onto the outer peripheral surface of the wound
prepreg sheets; and heating the molded prepreg sheets to the
predetermined temperature to thermally set the heated prepreg
sheets, to form a fiber reinforced plastic that is integrated with
the core member.
[0020] Another method of producing the robot hand member described
above comprises the steps to be sequentially executed of: dividing,
into a plurality of regions, the outer peripheral surface of a core
member that is in a predetermined shape in cross section and is not
deformed by the heating at temperatures equal to or lower than a
predetermined temperature and adhering prepreg sheets each
containing a reinforcing fiber onto at least one of the divided
regions; heating the core member onto which the prepreg sheets are
adhered, to the predetermined temperature, to thermally set the
member, to form a fiber reinforced plastic.
[0021] A further method of producing the robot hand member
described above comprises the steps to be sequentially executed of:
dividing, into a plurality of regions, the outer peripheral surface
of a core member that is in a predetermined shape in cross section
and is not deformed by the heating at temperatures equal to or
lower than a predetermined temperature and adhering prepreg sheets
each containing a reinforcing fiber onto each of the divided
regions; heating the core member onto which the prepreg sheets are
adhered, to the predetermined temperature, to thermally set the
member, to form a fiber reinforced plastic that is integrated with
the core member. In this case, the prepreg sheets in the regions
adjacent to one another are bonded and adhered to one another to
constitute the FRP on the whole of the outer peripheral surface of
the core member. Therefore, by using a core member in lightweight,
it is possible to produce a robot hand member having a merit of the
solid FRP member, a favorable anti-deflection characteristic and
flatness.
[0022] A robot hand member according to the present invention,
which is mounted on an arm unit of an industrial robot and is made
of fiber reinforced plastic, is formed in a hollow rectangular
shape in transverse cross section and is formed with, in an inner
space of a constituent member extending in a longitudinal
direction, at least one rib that extends across the long sides
opposing to each other in the transverse cross section, and also
extends in a longitudinal direction of the inner space.
[0023] According to this constitution, since the long sides
constituting the transverse cross section are connected to each
other via the rib, the long sides is substantially shortened in
length to increase the rigidity thereof. Since the rigidity of the
long sides in the transverse cross section is improved, the dent at
the center of the long sides is decreased and, hence, the flatness
(that is, precision) of the robot hand member is improved.
[0024] A method of producing the robot hand member described above
comprises the steps to be sequentially executed of: arranging core
members each of which has a rectangular shape in transverse cross
section and is not deformed by the heating at temperatures equal to
or lower than a predetermined temperature, on both side surfaces of
a rib-constituting member formed in a rectangular shape in
transverse cross section and containing a reinforcing fiber, to
form a composite structure having a rectangular shape in cross
section as a whole; laminating prepreg sheets each containing a
reinforcing fiber in a predetermined thickness on the outer
peripheral surfaces of the composite structure; heating the
composite structure on which the prepreg sheets are laminated to
the predetermined temperature, to form a fiber reinforced plastic
in which the rib-constituting member and the prepreg sheets are
integrated; and removing the core members from the fiber reinforced
plastic.
[0025] According to this constitution, if a plurality of kinds of
core members and rib-constituting members having different sizes
are prepared, by arbitrarily combining these members, a robot hand
member of a predetermined size having a rib in an inner space
thereof can be easily produced.
[0026] Another method of producing the robot hand member described
above comprises the steps to be sequentially executed of:
laminating prepreg sheets each containing a reinforcing fiber in a
predetermined thickness on the outer peripheral surfaces of core
members each of which has a rectangular shape in transverse cross
section and is not deformed by the heating at temperatures equal to
or lower than a predetermined temperature; bringing the plurality
of core members on which the prepreg sheets are laminated,
respectively, into contact with one another on their side surfaces
to form a composite structure having a rectangular shape in cross
section as al whole; laminating prepreg sheets each containing a
reinforcing fiber in a predetermined thickness on the outer
peripheral surface of the composite structure; heating the
composite structure on which the prepreg sheets are laminated to
the predetermined temperature, to form a fiber reinforced plastic
in which the prepreg sheets laminated on the core members and the
prepreg sheets laminated on the composite structure are integrated;
and removing the core members from the fiber reinforced plastic. In
this case, there is an advantage in that no rib-constituting member
is necessary.
[0027] In the above-mentioned production method, the step of
laminating prepreg sheets in a predetermined thickness may be
executed so that the prepreg sheets formed to meet the shape of the
surface of the composite structure or the shapes of the surfaces of
the core members are adhered and laminated on the surface of the
composite structure or the surfaces of the core members. By
adhering the prepreg sheets formed to meet the shape of the surface
of the composite structure or the shapes of the surfaces of the
core members, the prepreg sheets are laminated in the predetermined
thickness.
[0028] In the above-mentioned production method, further, the step
of laminating prepreg sheets in a predetermined thickness may wind
to laminate the prepreg sheets on the outer peripheral surface of
the composite structure or the outer peripheral surfaces of the
core members. By winding the prepreg sheets on the outer peripheral
surface of the composite structure or the outer peripheral surfaces
of the core members, the prepreg sheets are laminated in the
predetermined thickness.
[0029] A further method of producing the robot hand member
described above comprises the steps to be sequentially executed of:
bringing a plurality of unit constituent members each having a
hollow rectangular shape in transverse cross section and containing
a reinforcing fiber into contact with one another on their side
surfaces, to form a composite structure having a rectangular shape
in cross section as a whole; adhering prepreg sheets each
containing a reinforcing fiber over the side surfaces on the same
sides intersecting the contacting surfaces of the composite
structure; and heating the composite structure onto which the
prepreg sheets are adhered, to a predetermined temperature, to form
a fiber reinforced plastic in which the unit constituent members
and the prepreg sheets are integrated.
[0030] In the above-mentioned production method, the step of
adhering prepreg sheets may wind to adhere the prepreg sheets onto
the outer peripheral surface of the composite structure. According
to this constitution, since the prepreg sheets are wound on the
outer peripheral surface of the composite structure, the step
between the adjacent unit constituent members is concealed and the
appearance of the robot hand is improved.
[0031] In the above-mentioned methods, the step of winding or
adhering prepreg sheets onto the outer surfaces of the core member
or the surface of the composite structure may include a step of
winding or adhering the prepreg sheets in a multi-layer. Thus, it
becomes possible to suitably design prepreg sheet laminates of
different thickness and, hence, to control the flexural rigidity of
the robot hand member.
[0032] The step of winding or adhering prepreg sheets in a
multi-layer may further include a step of laminating the prepreg
sheets in a manner that the reinforcing fibers therein are oriented
differently to each other in a direction along the longitudinal
direction and in a direction nearly at a right angle with the
longitudinal direction. According to this constitution, it becomes
possible to control the flexural rigidity, the vibration
attenuation characteristics, the heat resistance and the like of
the robot hand member in accordance with an environment in which
the robot hand is used.
[0033] Further, the step of winding or adhering prepreg sheets in a
multi-layer may include a step of winding a cloth prepreg sheet on
the outermost layer on which the prepreg sheets are wound or
adhered. According to this constitution, the fluffing in a
subsequent working of cutting or polishing is reduced. Thus, the
working performance as a member is improved, and the product that
is finally obtained exhibits improved appearance.
[0034] Other objects, features and advantages of the present
invention will become obvious from the following description of the
embodiments in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] FIG. 1 is a perspective view illustrating a robot hand to
which a robot hand member of the present invention is applied;
[0036] FIG. 2 is a perspective view illustrating a robot hand
member of a first embodiment according to the present
invention;
[0037] FIG. 3 is a sectional view illustrating processes of a first
method of producing the robot hand member of the first
embodiment;
[0038] FIG. 4 is a diagram for explaining a state where prepreg
sheets are laminated in a manner that reinforcing fibers of the
prepreg sheets are oriented in directions different to each other
in a process of winding the prepreg sheets in a multi-layer in the
production method;
[0039] FIG. 5 is a sectional view illustrating a modified example
of sectional shape of the robot hand member of the first
embodiment;
[0040] FIG. 6 is a diagram for explaining processes of a second
method of producing the robot hand member of the first
embodiment;
[0041] FIG. 7 is a sectional view illustrating a robot hand member
of a second embodiment according to the present invention;
[0042] FIG. 8 is a perspective view illustrating a modified example
of the robot hand member of the second embodiment;
[0043] FIG. 9 is a sectional view illustrating a robot hand member
of a third embodiment according to the present invention;
[0044] FIG. 10 is a sectional view illustrating processes of a
first method of producing the robot hand member of the third
embodiment;
[0045] FIG. 11 is an explanatory diagram illustrating an example of
laminated state of prepreg sheets in the first method of producing
the robot hand member of the third embodiment;
[0046] FIG. 12 is a sectional view illustrating processes of a
second method of producing the robot hand member of the third
embodiment;
[0047] FIG. 13 is a sectional view illustrating processes of a
third method of producing the robot hand member of the third
embodiment; and
[0048] FIG. 14 is a view illustrating a production method
corresponding to a case where the robot hand member of the third
embodiment is long, wherein FIG. 14A is a side view of the robot
hand member, FIG. 14B is a sectional view along E-E in FIG. 14A,
FIG. 14Cis a sectional view along F-F in FIG. 14A, and FIG. 14D is
a sectional view along G-G in FIG. 14A.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0049] Embodiments of the present invention will now be described
in detail with reference to the accompanying drawings.
[0050] FIG. 1 is a perspective view illustrating a robot hand 1 to
which a robot hand member of the present invention is applied. The
robot hand 1 is mounted on an arm unit of an industrial robot, and
comprises a flat plate-like mounting member 2 for mounting the
robot hand 1 on the arm unit of the robot (not shown) and a robot
hand member 4 secured to the mounting member 2 to support a
workpiece 3. In FIG. 1, reference numeral 5 denotes a mounting hole
perforated in the mounting member 2 for mounting the robot hand 1
on the arm unit of the robot. The robot hand member 4 supports and
conveys the workpiece 3 such as a glass substrate or the like, for
example, a liquid crystal display (LCD), a plasma display panel
(PDP) or a semiconductor wafer, and is made of fiber reinforced
plastic (FRP) so as to achieve a lightweight, excellent flatness,
flexural rigidity and heat resistance.
[0051] FIG. 2 illustrates a robot hand member 4 of a first
embodiment according to the present invention. The robot hand
member 4 is in the form of a hollow square pipe having a hollow
structure constituted such that prepreg sheets each containing a
reinforcing fiber are laminated on the outer peripheral surface of
a core member, the laminated prepreg sheets are heated to a
predetermined temperature to be thermally set, to form a fiber
reinforced plastic, and the core member is removed from the thus
formed fiber reinforced plastic. Two robot hand members 4 are
mounted in parallel with each other on the mounting member 2 by
using screws or the like, and each has a size of about 50 mm in
width and about 1500 mm in length. The mounting member 2 and the
robot hand members 4 may be integrated.
[0052] A first method of producing the root hand member 4 will now
be described with reference to FIG. 3.
[0053] Referring to FIG. 3A, first, prepreg sheets 7 each
containing a reinforcing fiber are wound in a multi-layer on the
outer peripheral surface of a core member 6 made of material that
is not deformed by the heating at temperatures equal to or lower
than a predetermined temperature and has a predetermined shape in
cross section.
[0054] The core member 6 serving as a base member on which the
prepreg sheets 7 are to be wound, is not substantially deformed by
the heating at temperatures less than a temperature which is
slightly higher than the temperature in a process in which a
prepreg sheet laminate 9 that will be described later is heated to
the predetermined temperature (although different depending on the
resin, usually about 100 to about 190.degree. C.) to be thermally
set, and also the core member 6 is made of material that can be
easily removed from the FRP after the heating and thermosetting, to
be formed, for example, in a rectangular rod in cross section.
Here, the wording "the core member 6 is not substantially deformed
by the heating" means that the core member 6 is not melted or is
not deformed by the heating due to such as warping, bending,
deflection, twisting, wrinkling or folding in the process of
heating to thermally set the prepreg sheet laminate 9. The core
member 6 is made of metal such as aluminum, steel or stainless
steel, or a resin such as an MC nylon resin or a polyimide resin.
The above metal or resin has a coefficient of thermal expansion
larger than that of FRP, and therefore is contracted by cooling
after it has been heated, and is easily removed. As required,
further, a parting material may be applied to the surface of the
core member. The parting material may be a chemical (e.g.,
surfactant, etc.) that is applied by spraying, or may be a parting
sheet such as Teflon sheet.
[0055] The prepreg sheet 7 is a sheet of a so-called one-direction
member such as a one-direction plain-woven fabric or a
one-direction non-woven fabric in which the reinforcing fibers are
oriented in one direction, a two-direction member such as a
plain-woven fabric, a twilled fabric or a satin-woven fabric in
which the reinforcing fibers are oriented in two directions, or a
three-direction member such as a triaxially-woven fabric in which
the reinforcing fibers are oriented in three directions, which is
impregnated in advance with a matrix resin, and is placed in a
state of not yet thermally set having a viscosity to some
extent.
[0056] In this case, a carbon fiber is generally used as the
reinforcing fiber from the standpoint of attaining rigidity and
lightweight. It is, however, also possible to use a glass fiber, an
aramide fiber or a silicon carbide fiber other than the carbon
fiber. For example, for a plurality of prepreg sheets 7 to be
laminated, carbon fiber prepreg sheets may be mainly used, and
prepreg sheets containing the glass fiber or any other fiber may be
partially used to the extent that the supporting performance or the
conveying performance of the robot hand member is not damaged. The
carbon fibers can be classified into two types; i.e.,
polyacrylonitrile-based (PAN) carbon fibers and pitch-based carbon
fibers depending upon the starting materials. The pitch-based
carbon fibers have high elasticity of 490 to 950 GPa, while the
PAN-based carbon fibers have elasticity of about 230 to about 490
GPa and high tensile strength.
[0057] As the matrix resin, further, there can be used a thermoset
resin such as epoxy resin, phenol resin, cyanate resin, unsaturated
polyester resin, polyimide resin or bismaleimide resin. In order to
impart shock resistance and toughness, further, there can be used
the one obtained by adding fine particles of a rubber or a resin to
the thermoset resin or the one obtained by dissolving a
thermoplastic resin in the thermoset resin. Here, the rubber to be
used as fine particles may be a nitrile rubber, a butadiene rubber,
a styrene-butadiene rubber, a butadiene-nitrile rubber, acrylic
rubber or a butyl rubber. Further, the resin to be used as fine
particles may be a thermoset resin or a thermoplastic resin. As the
thermoset resin, there can be used an epoxy resin, a phenol resin,
an unsaturated polyester resin, an amino resin or a urethane resin.
As the thermoplastic resin, there can be used a polyimide resin, a
polyacrylate resin, a polyvinyl acetate resin, a polyamide resin, a
polyaramide resin or a polycarbonate resin. As the thermoplastic
resin to be dissolved in the thermoset resin, there can be used a
polysulfone resin, a polycarbonate resin, a polyether sulfone
resin, a polyether imide resin, an aromatic polyester resin, a
polyvinyl formal resin, a polyamide resin, or a polyimide
resin.
[0058] Here, the process of winding the prepreg sheets 7 in a
multi-layer is executed, as shown in FIG. 4, such that the prepreg
sheets 7 are laminated in a manner that the reinforcing fibers are
oriented in different directions. That is, the prepreg sheets are
laminated so that a reinforcing fiber 8a of a prepreg sheet 7a of a
given layer is oriented in a direction of 0 degree, and a
reinforcing fiber 8b of a prepreg sheet 7b of another layer is
oriented in a direction of 90 degrees. There may be further
laminated a prepreg sheet 7c of a further layer in addition to the
above-mentioned prepreg sheets. In this case, a reinforcing fiber
8c of the prepreg sheet 7cmay be a cloth prepreg sheet in which the
reinforcing fibers oriented in two directions are intersecting at
an angle of 90 degrees, or may be the one constituted by laminating
a pair of the one-directional prepreg sheets at angles of .+-.45
degrees with respect to a longitudinal direction. In this state,
the prepreg sheets 7a, 7b and 7c of the respective layers are
successively laminated in a suitable thickness, so that the final
thickness will be from about 1 to about 7 mm. The thickness of the
laminate in this case will be slightly larger than the required
thickness of the FRP plate of the robot hand member taking into
consideration a reduction in the volume at the time when the
prepreg sheets are heated to be thermally set.
[0059] An example of laminating the prepreg sheets 7 in a
multi-layer will be described in detail hereunder. Referring to
FIG. 3A, an innermost layer prepreg sheet 7 to be laminated in
contact with the core member 6 has the reinforcing fiber oriented
in a direction of, for example, 0 degree or 90 degrees with respect
to the longitudinal direction. A second prepreg sheet 7 to be
laminated on the above innermost layer has the reinforcing fiber
oriented in a direction of, for example, 0 degree with respect to
the longitudinal direction, to prevent deflection in the
longitudinal direction and to improve the vibration attenuation
characteristics. A third prepreg sheet 7 to be laminated on the
above-mentioned second prepreg sheet 7 has the reinforcing fiber
oriented in a direction of, for example, 90 degrees with respect to
the longitudinal direction, to improve flexural rigidity, to
improve the vibration attenuation characteristics for flexural
vibration and to prevent warping and deflection, of the whole
member inclusive of the laminated two prepreg sheets 7. In addition
to the above, there may be added a layer of prepreg sheet 7 having
reinforcing fibers oriented in the directions of, for example,
.+-.45 degrees with respect to the longitudinal direction. In this
case, it is possible to improve the torsional rigidity and the
torsional vibration attenuation characteristics in the member as a
whole. It is further possible to laminate a cloth prepreg sheet as
the outermost layer other than the prepreg sheets 7. The cloth
prepreg sheet is the one constituted by a woven fabric of
reinforced fiber. The reinforcing fiber is preferably a carbon
fiber, a glass fiber, an aramid fiber or a silicon carbide fiber,
and plain-woven, twilled-woven, satin-woven or triaxially woven can
be appropriately used. The cloth prepreg sheet is laminated in
order to decrease fluffing in a subsequent process of cutting or
grinding, to improve workability and to improve appearance of the
product.
[0060] As for order for laminating the prepreg sheets 7 in a
multi-layer, it is preferable to laminate the 90-degree-oriented
sheet as the lowermost layer (innermost layer) from the standpoint
of easily removing the core member 6. This is because the carbon
fiber has a degree of heat shrinkage lower than that of the matrix
resin and, hence, the degree of shrinkage for the sheet becomes
such that the degree of shrinkage in the fiber orientation
direction becomes lower than that in the fiber arrangement
direction. The 90-degree-oriented sheet is used for the inner
surface of the pipe-like FRP plate, so that the carbon fiber is
oriented so as to surround the outer peripheral surface of the core
member 6. Therefore, when subjected to the thermosetting, the
diameter of the pipe-like FRP plate is not so much contracted.
[0061] Further, the prepreg sheets (outer sheets) to be laminated
on the upper layers contribute highly to the improvement of
characteristics (flexural rigidity, etc.) of the robot hand member.
It is therefore preferable that the 0-degree-oriented sheet is
laminated on an upper layer of the 90-degree-oriented sheet from
the standpoint of prevention of deflection. The combination of the
prepreg sheets to be used and order of lamination may be determined
while taking the above-mentioned points into consideration.
[0062] Next, as shown in FIG. 3B, outer molds 10a and 10b each
having a predetermined inner surface shape are pushed onto the
outer peripheral surface of the prepreg sheet laminate 9 wound with
the prepreg sheets in a multi-layer, to mold the outer surface
shape of the prepreg sheet laminate 9 in a predetermined size. This
is because, as the prepreg sheets 7 are wound in an increased
number of layers on the core member 6 shown in FIG. 3A, the corners
swell toward the outer side and the shape at the corners lacks
uniformity. Therefore, the corners are molded in an appropriate
right-angled shape. For this purpose, the two channel-shaped outer
molds 10a and 10b each having an inner peripheral surface of a
U-shape are arranged so as to face each other over and under the
prepreg sheet laminate 9, and are pushed as indicated by arrows A
and B in the same manner as a press work. Thereby, the corners of
the prepreg sheet laminate 9 are pushed into an appropriate
right-angled shape by the U-shaped inner surface shape of each of
the outer molds 10a and 10b.
[0063] Next, as shown in FIG. 3C, the thus molded prepreg sheet
laminate 9 is heated to the predetermined temperature to be
thermally set, to form a fiber reinforced plastic(FRP). At this
time, the whole prepreg sheet laminate 9 is put into, for example,
a vacuum bag to be heated. The heating temperature conditions are
such that the temperature is elevated at a rate of, for example, 2
to 10.degree. C./min from the room temperature, maintained at about
100 to 190.degree. C. for about 60 minutes, thereafter heating is
stopped, and the prepreg sheet laminate 9 is allowed to cool
naturally down to the room temperature. Thereby, the whole prepreg
sheet laminate 9 is thermally set to form the FRP. Here, the core
member 6 is made of material that is not deformed by the heating at
temperatures equal to or lower than the predetermined temperature
and, hence, correctly maintains the sectional shape thereof without
substantially deformed through the above-mentioned heating process.
Note, the prepreg sheet laminate 9 is put into the vacuum bag in
order to suck air bubbles staying among the sheets formed in the
laminating process, and to apply the substantially uniform external
pressure (atmospheric pressure) onto the prepreg sheet laminate
9.
[0064] Next, as shown in FIG. 3D, the core member 6 is removed from
the FRP member 11 to realize a hollow structure. Thus, a robot hand
member 4 in the form of a square pipe is produced as shown in FIG.
2.
[0065] Since the robot hand member 4 in this embodiment is not
constituted as a solid FRP member but is constituted as a hollow
structure, it is possible to realize a reduction in weight without
decreasing the volume of the robot hand member itself (i.e.,
without decreasing the thickness or the width). In a case of, for
example, a long robot hand member 4 to be mounted on the mounting
member 2, it is possible to avoid that the end thereof is deflected
or vibrated by its own weight or by a load of the workpiece, so
that the accuracy of supporting and conveyance of the workpiece 3
can be improved. The hollow portion of the square pipe can be
utilized to arrange a tube for blowing or sucking air in order to
support and convey the workpiece 3, and also to arrange electric
wires for sensors that detect the presence or holding of the
workpiece 3.
[0066] The sectional shape of the robot hand member 4 is not
limited to the above-mentioned square pipe but may be of any shape,
such as a triangular shape, a polygonal shape, a circular shape or
a semi-circular shape. As shown in FIG. 5, for example, the robot
hand member 4 may be of the shape of a pipe having a flat upper
surface and an arcuate lower surface. In this case, the core member
shown in FIG. 3A has a sectional shape with a flat upper surface
and an arcuate lower surface. In the foregoing description, the
prepreg sheets 7 are wound in a multi-layer on the outer peripheral
surface of the core member 6. However, the present invention is not
limited thereto, when the prepreg sheet 7 is formed in a
predetermined thickness to have the flexural rigidity and vibration
attenuation characteristics, such a prepreg sheet 7 may be wound in
a single layer.
[0067] Next, a second method of producing the robot hand member 4
will be described with reference to FIG. 6.
[0068] First, in a preparation process, the core member 6 and
starting prepreg sheets 7 are prepared. The core member 6 is formed
to meet the shape of the robot hand member 4, and is made of member
having a rectangular shape in transverse cross section. As the
starting prepreg sheets 7, various types of prepreg sheets are
prepared, in which the types of reinforcing fibers are different,
the densities of reinforcing fibers are different relative to the
matrix resin, or the orientations of reinforcing fibers are
different. The prepreg sheets 7 to be used are selected in a plural
number corresponding to the object of use of the robot hand 1 and
the place where the robot hand member 4 is used, so as to form a
carbon fiber composite material having the optimum flexural
rigidity.
[0069] Then, as shown in FIG. 6A, the starting prepreg sheet 7 is
cut to form prepreg sheet pieces 7', 7" of predetermined shapes.
The prepreg sheet pieces 7', 7" are those to be laminated on
respective divided regions (namely, upper surface, lower surface,
left side surface and right side surface) of the outer peripheral
surface of the core member 6, and are cut off from all starting
prepreg sheets 7 to meet the sizes of the divided regions of the
core member 6.
[0070] Next, as shown in FIG. 6B, the prepreg sheet pieces 7', 7"
are laminated on the surfaces of the core member 6 to be adhered.
The prepreg sheet pieces 7', 7" have not yet been set, and each has
an adhering force to some extent. Therefore, the prepreg sheet
pieces 7', 7" can be adhered onto the core member 6 on which a
parting film has been stuck by simply laminating the sheets
successively. However, it is preferable to pressing the prepreg
sheet pieces 7', 7" while heating by means of an iron or the like.
It is further preferable to laminate the prepreg sheet pieces 7',
7" so that the reinforcing fibers are oriented in the longitudinal
direction and in a direction at right angles with the longitudinal
direction.
[0071] Thus, the prepeg sheet pieces 7', 7" are laminated to be
adhered onto the whole outer peripheral surface of the core member
6, to thereby form a member in a state where the outer peripheral
surface of the core member 6 is covered with the prepreg sheet
laminate 9.
[0072] Then, as shown in FIG. 6C, a cloth prepreg sheet 7d is wound
on the outer periphery of the prepreg sheet laminate 9 one turn or
few turns. By such a covering, it is possible to prevent the
fluffing or fine splitting in the subsequent processing. Besides,
even if there may be caused burring or steps at portions where the
prepreg sheet pieces 7', 7" are joined together, it is possible to
cover such burring or steps. Thereby, fine workpieces such as
liquid crystal displays, plasma displays and silicon wafers are
prevented from being scarred.
[0073] Then, as shown in FIG. 6D, the outer molds 10c and 10d
(i.e., two holder plates 10c, and two thickness-setting plates 10d
inserted between the two holder plates) are pushed onto the member
covered with the cloth prepreg sheet 7d from the four sides. In
this case, the holder plates 10c are pushed onto the upper and
lower surfaces of the prepreg sheet laminate 9 in a state covered
with the cloth prepreg sheet 7d, and the thickness-setting plates
10d are pushed onto the right and left side surfaces.
[0074] Thereafter, the prepreg sheet laminate 9 is put into a
vacuum bag and is heated under predetermined conditions to be
thermally set to form a fiber reinforced plastic (FRP). At this
time, an external pressure in a specific direction may be exerted
on the prepreg sheet laminate 9. For example, if the prepreg sheet
laminate 9 is pressed from the upper side by means of a weight or
the like so that no gap develops between the holder plates 10c and
the thickness-setting plates 10d, the flatness of the upper surface
(that is, supporting surface) of the robot hand member 4 is further
improved and also a highly precise size (particularly, thickness)
is obtained. Further, if the outer molds at the opposing positions
are pushed by means of a vice or the like as indicated by arrows A
and B or C and D, the joining performance of the adjacent prepreg
sheet pieces 7', 7" at the edges thereof is further improved.
[0075] Then, as shown in FIG. 6E, the core member 6 is removed from
a member 11 being the FRP through the above-mentioned processes.
Thus, there is formed the robot hand member 4 of the hollow
structure.
[0076] According to this production method, since the core member 6
has two functions of a so-called base member when laminating the
prepreg sheet 7 and a so-called inner mold when heat-molding the
robot hand member 4, it is possible to perform simultaneously the
forming of the FRP plate (i.e., the laminating of prepreg sheet
piece 7' or 7") and the molding of the robot hand member 4 (i.e.,
to join the prepreg sheet pieces 7' and 7" of the adjacent
walls.
[0077] Therefore,, it is possible to decrease the number of the
production processes compared to a production method in which a
skin layer is formed of the conventional FRP plate, and the skin
layer is joined to a core layer serving as a core member. In
particular, the naturally cooling time in the stage of forming the
FRP plate is integrated with the time of adhesion in the stage of
forming the robot hand member. Thus, it is possible to greatly
decrease the time required for the production.
[0078] Further, for the method of producing the robot hand member
of the hollow structure, there can be contrived a method of
adhering together at the edges of the FRP plates of the four
surfaces formed to meet the wall surfaces of the robot hand member.
According to this method, however, there are disadvantages in that
a complicated operation is required for adhering the FRP plates of
the four surfaces at the edges thereof, the dimensional precision
is decreased, the strength at the adhered portions is likely to be
decreased, and the number of processes are increased since the FRP
plates that have been formed by using the prepreg sheets are joined
together. Contrary to this, according to the production method in
this embodiment, since the robot hand member can produced by a
relatively simple operation of adhering the prepreg sheet pieces
7', 7" onto the core member 6, the robot hand member of high
dimensional precision can be produced within a short period of time
maintaining. Besides, since the prepreg sheet pieces 7', 7" of the
adjacent sections are adhered together simultaneously with the
thermosetting of the prepreg sheet 7, it is possible to increase
the strength at the joining portions.
[0079] Further, differently from the above-mentioned first
production method, the corners are not swollen toward the outer
side when the prepreg sheets are wound on the outer peripheral
surface of the core member. Therefore, there is no need of using a
dedicated outer mold that meets the outer surface shape of the
robot hand member. In particular, since the outer mold is usually
larger and more expensive than the inner mold, a high cost is
necessary to separately prepare the outer molds or to provide
various outer molds to meet the shapes of the robot hand members.
According to this production method, however, there is only needed
a general-purpose outer mold (i.e., holder plates 10c and
thickness-setting plates 10d). Therefore, it is possible to
suppress the cost required for the design modification of the robot
hand and to improve the freedom of design. Thus, it is possible to
quickly produce the robot hand member that meets the user
requirements and to shorten the due term.
[0080] This production method is the same as the first production
method with respect to that the robot hand member 4 may have a
triangular shape, a polygonal shape, a circular shape or a
semicircular shape in cross section, that the cloth prepreg sheet
7d needs not necessarily be wound on the outermost circumference of
the prepreg sheet laminate 9, and that the prepreg sheet pieces 7',
7" to be adhered onto the core member 6 may be of a single
layer.
[0081] FIG. 7 illustrates a robot hand member 14 according to a
second embodiment of the present invention. This robot hand member
14 is of a solid structure constituted by laminating prepreg sheets
7 each containing a reinforcing fiber on the whole peripheral
surface of the core member 6, and heating the thus formed prepreg
sheet laminate to a predetermined temperature to thermally set, to
form a fiber reinforced plastic integrated with the core member
6.
[0082] A first method of producing the robot hand member 14 will be
described hereunder. This production method complies with the first
method of producing the robot hand member 4 in the first embodiment
shown in FIG. 3. As the core member 6 having a predetermined shape
in cross section in FIG. 3A, there is used a light-weight member
made of, for example, a synthetic resin lighter than the FRP, which
is not deformed by the heating at temperatures equal to or lower
than a predetermined temperature and has the excellent adhesion
performance to the prepreg sheet. The light-weight member is formed
of a material which does not develop a gap to the FRP after molded
by being heated, at temperatures equal to or less than a
temperature slightly higher than the temperature in the process of
heating the prepreg sheet laminate 9 to a predetermined temperature
(although different depending upon the resin, usually from about
100 to about 190.degree. C.) to thermally set. For example, there
can be used such plastic materials as epoxy resin, phenol resin,
unsaturated polyester resin, polyimide resin, bismaleimide resin,
polyurethane resin and foamed materials thereof. The core member 6
may have its surfaces coarsened by being blasted with sand or by
using a sand-paper in order to improve adhesion to the prepreg
sheets 7. As required, further, an adhesive may be applied.
[0083] The production processes are executed quite in the same
manner as the processes shown in FIGS. 3A, 3B and 3C. However, the
process of obtaining the hollow structure by removing the core
member 6 from the FRP member 11 shown in FIG. 3D is not executed.
Namely, the production method is terminated with the process of
heating the prepreg sheet laminate 9 shown in FIG. 3C to a
predetermined temperature to thermally set, to form the FRP. In
this case, too, since the core member 6 is made of material that is
not deformed by the heating at temperatures equal to or lower than
the predetermined temperature, it is not substantially deformed
through the process of heating shown in FIG. 3C and correctly
maintains its shape in cross section.
[0084] Thus, there is produced the robot hand member 14 of a solid
structure with the core member 6 made of light-weight material
remaining in the FRP. Then, there are formed, by machining, an air
blow passage or an air suction passage for supporting and conveying
the workpiece 3, a hole for arranging electric wires for a sensor
that detects whether the workpiece 3 is present or is supported,
and threaded holes for mounting. In the solid structure having the
core member 6 in this embodiment, too, the decrease of the weight
and the decrease of the number of the production processes are
achieved.
[0085] The robot hand member 14 of the solid structure does not
require the process of removing the core member 6 and thus, it is
possible to greatly shorten the time required for the production.
Further, since the core member 6 made of light-weight member is
left, it is possible to eliminate disadvantages inherent in both
the robot hand member of the hollow structure and the robot hand
member made of the solid material. That is, in the case of the
robot hand member of the hollow structure, there are disadvantages
in that deformation with the time elapse such as denting in the
central portion accompanying the use is caused, or, it is forced to
modify the design concerning the portions where the grooves and
holes are formed when replacing the conventional robot hand member
made of the solid material by a new one. The robot hand member of
the solid structure of this embodiment, however, is free from such
disadvantages. Besides, the weight of the robot hand member as a
whole can be decreased in a state of having a volume same as that
of the robot hand member made of the solid material. It is
therefore possible to suppress not only the deflection due to its
own weight but also to suppress the deflection due to the load.
[0086] Next, a second method of producing the robot hand member 14
will be described. This production method complies with the second
method of producing the robot hand member 4 in the first embodiment
shown in FIG. 6. Like the first production method, for the core
member 6, a light-weight material that has the excellent adhesion
performance to the prepreg sheets and is lighter than the FRP
member. In order to improve the adhesion performance to the prepreg
sheet pieces 7', 7", it is preferable that the core member 6 has
its surfaces coarsened or coated with an adhesive.
[0087] The processes of production are executed quite in the same
manner as the processes shown in FIGS. 6A, 6B, 6C and 6D. However,
the process of forming the hollow structure by removing the core
member 6 from the FRP member 11 shown in FIG. 6E is not executed.
Namely, the production method is terminated with the process of
heating the prepreg sheet laminate 9 shown in FIG. 6D to a
predetermined temperature to thermally set, to obtain the FRP.
[0088] Thus, there is produced the robot hand member 14 of a solid
structure with the core member 6 made of light-weight material
remaining in the FRP.
[0089] FIG. 8 illustrates a modified example of the robot hand
member 14 in the second embodiment. A robot hand member 14' is of a
solid structure in which a prepreg sheets each containing a
reinforcing fiber is laminated on a part of the outer peripheral
surface of a core member, and heating the member on which the
prepreg sheets are laminated to a predetermined temperature to
thermally set, to form a fiber reinforced plastic integrated with
the core member.
[0090] This method of producing the robot hand member complies with
the second method of producing the robot hand member 14 in the
second embodiment. The method is performed nearly in the same
manner as the processes shown in FIGS. 6A to 6D except for that the
prepreg sheet pieces 7' is laminated on only at least one of the
divided regions (i.e., upper surface 6a and lower surface 6b) of
the outer peripheral surface of the core member 6 in FIGS. 6A and
6B. Thus, there is produced the robot hand member 14' of the solid
structure in which the core member 6 made of light-weight material
is sandwiched by the FRPs.
[0091] In this robot hand member 14', the joining performance is
required to be ensured between the core member 6 and the lowermost
prepreg sheet piece 7'. Here, however, since the prepreg sheets 7
that have not yet been set is integrated with the core member due
to the thermosetting, the joining performance is ensured to a
sufficient degree. In order to further improve the joining
performance, the surfaces (6a, 6b) of the core member 6 on which
the prepreg sheets are to be laminated may be coarsened or may be
coated with an adhesive. In the process of FIG. 6D, further, the
thickness-setting plate 10d serving as the outer mold may be
omitted.
[0092] According to this robot hand member 14', a small amount of
the prepreg sheets 7 are used and therefore, the material cost is
greatly decreased.
[0093] FIG. 9 illustrates a robot hand member 16 in a third
embodiment according to the present invention. The robot hand
member 16 is made of the FRP that is light in weight, and has
excellent flatness, flexural rigidity and heat resistance. Here,
the FRP is the one obtained by molding, into a predetermined shape,
a prepreg sheet that is obtained by impregnating a reinforcing
fiber such as carbon fiber, glass fiber, aramide fiber or silicon
carbide fiber with a thermoset resin, and heating the prepreg sheet
to a predetermined temperature to thermally set. The robot hand
member 16 has at least one rib 16B extending between the opposing
long sides in transverse cross section and also extending in a
space formed by the constituent members 16A that is formed in a
hollow rectangular shape in cross section and extends in the
longitudinal direction.
[0094] According to this constitution, the long sides constituting
the transverse cross section of the robot hand member 16 are
connected to each other via the rib 16B, whereby the length of the
long sides is substantially shortened to increase the rigidity.
Further, the dent at the center of the long side is decreased to
improve the flatness, i.e., to improve the precision of the robot
hand member 16. In this case, since a sufficient degree of strength
can be obtained even without increasing the thickness of the robot
hand member 16, it is possible to prevent the increase in the
deflection at the end caused by the increase in the weight.
[0095] Next, a first method of producing the robot hand member 16
will be described with reference to FIG. 10.
[0096] In a first process (see FIG. 10A), the core members 6 each
of which has a rectangular shape in transverse cross section and is
not deformed by the heating at temperatures equal to or lower than
a predetermined temperature, are arranged on both side surfaces of
rib-constituting member 17 having a rectangular shape in transverse
cross section and containing a reinforcing member, to form a
composite structure 18 having a rectangular shape in cross section
as a whole.
[0097] Like the one used for the robot hand member in the first
embodiment, the core member 6 is formed of a material that is not
substantially deformed by the heating at temperatures equal to or
less than a temperature slightly higher than a predetermined
temperature for heating to thermally set the prepreg sheet and can
be easily removed from the FRP after the heating and the
thermosetting.
[0098] The rib-constituting member 17 is formed of a material that
contains a reinforcing fiber such as carbon fiber, glass fiber,
aramide fiber or silicon carbide fiber, and is integrated with the
prepreg sheet when the prepreg sheet is thermally set. It is
preferable that the rib-constituting member 17 is formed by
cutting, into a predetermined size, the FRP formed in a plate shape
by thermally setting the prepreg sheet in which the reinforcing
fibers are laminated with the orientations thereof being different
to each other.
[0099] In a second process (see FIG. 10B), the prepreg sheets 7
containing the reinforcing fiber are laminated on the outer
peripheral surface of the composite structure 18 in a predetermined
thickness (e.g., about 1 to 7 mm). Here, in order to laminate the
prepreg sheets 7 in a predetermined thickness, as shown in FIG.
11B, on the surfaces (upper, lower, right and left surfaces) of the
composite structure 18, the prepreg sheets 7 formed to meet the
shapes of these surfaces may be adhered and laminated. As shown in
FIG. 11B, further, the prepreg sheets 7 may be wound and laminated
on the outer peripheral surface of the composite structure 18. The
adhesion and the winding in this case is preferably executed in
such a manner that the reinforcing fibers are oriented in different
directions.
[0100] As shown in FIGS. 11C and 11D, further, the cloth prepreg
sheet 7d constituted by a woven fabric of reinforcing fiber may be
wound on the outer peripheral surface of the composite structure 18
on which the prepreg sheets 7 have been laminated, cover the
composite structure 18.
[0101] In a third process (see FIG. 10C), the outer molds 10a and
10b each having a predetermined shape are pushed onto the outer
peripheral surface of the composite structure 18 on which the
prepreg sheets 7 are laminated, to thereby mold the outer surface
shape of the composite structure 18 into a predetermined size. As
the outer molds 10a and 10b, there may be used two channel-shaped
outer molds (shown in the figure) each having U-shaped inner
peripheral surface shape or four plate-like outer molds (FIG. 6D)
corresponding to the laminating mode of the prepreg sheets 7 (see
FIG. 11).
[0102] In a fourth process (not shown), the molded composite
structure 18 is heated to a predetermined temperature, to form the
FRP in which the rib-constituting members 17 and the prepreg sheets
7 are integrated.
[0103] In a fifth process (see FIG. 10D), the core member 6 is
removed from the FRP to realize the robot hand member having the
rib in inner space thereof.
[0104] According to the above-mentioned production method, the
robot hand member 16 is produced such that the core members 6 are
arranged on both side surfaces of the rib-constituting members 17
to form a composite structure 18 of a rectangular shape in cross
section as a whole, the prepreg sheets 7 are laminated on the outer
peripheral surface of the composite structure 18 in a predetermined
thickness to be molded by using the outer molds 10a and 10b, the
molded composite structure 18 is heated to a predetermined
temperature to form an FRP in which the rib-constituting members 17
and the prepreg sheets 7 are integrated, and the core members 6 are
removed therefrom. Therefore, if a plurality of kinds of core
members 6 and rib-constituting members 17 of different sizes, it is
possible to easily produce the robot hand member 16 of
predetermined size having the rib in the inner space thereof by
combining arbitrarily these members.
[0105] At this time, since the robot hand member 16 has the rib in
the inner space thereof, the long sides constituting the transverse
cross section are connected to each other through the rib.
Accordingly, the length of the long sides is substantially
shortened and the rigidity is increased. Since the dent is
decreased at the center of the long sides, it is possible to
improve the flatness, that is, the precision of the robot hand
member 16.
[0106] The number of the chambers (number of division) in the inner
space can be changed by changing the number of the core members 6
and the number of the rib-constituting members 17. In this case,
the inner space partitioned by the rib-constituting members 17 can
be utilized for arranging a tube for blowing or sucking the air for
supporting and conveying the workpiece, and for arranging the
electric wires for a sensor that detects whether the workpiece is
present or is held. In the robot hand of solid in cross section in
the prior art, the air suction passage and the like are formed by
machining. Contrary to this, the embodiment according to the
present invention can eliminate the cost required for the
machining.
[0107] FIG. 12 illustrates a second method of producing the robot
hand member 16.
[0108] In a first process (see FIG. 12A), the prepreg sheets 7 each
containing the reinforcing fiber are laminated, in a predetermined
thickness, on the outer peripheral surface of the core member 6
that is formed in a rectangular shape in transverse cross section
and is not deformed by the heating at temperatures equal to or
lower than a predetermined temperature. At this time, like in the
first production method, the prepreg sheets 7 formed to meet the
shapes of the surfaces (upper, lower, right and left surfaces) of
the core member 6 may be adhered and laminated on the surfaces, or
the prepreg sheets 7 may be wound and laminated on the outer
peripheral surface of the core member 6. The directions in which
the reinforcing fibers of the prepreg sheets are oriented may be
determined relying upon the same technical idea as that of the
first production method.
[0109] In a second process (see FIG. 12B), the side surfaces of a
plurality of (two in this embodiment) core members 6 on which the
prepreg sheets 7 are laminated are brought into contact with each
other, to form the composite structure 18 of a rectangular shape in
cross section as a whole.
[0110] In a third process (see FIG. 12C), the prepreg sheets 7 each
containing the reinforcing fiber are laminated, in a predetermined
thickness, on the outer peripheral surface of the composite
structure 18. At this time, like in the first production method,
the cloth prepreg sheet 7d may be wound on the outer peripheral
surface of the composite structure 18 on which the prepreg sheets 7
have been laminated, to cover the composite structure 18.
[0111] In a fourth process (see FIG. 12D), the outer molds 10a and
10b each having a predetermined shape are pushed onto the outer
peripheral surface of the composite structure 18 on which the
prepreg sheets 7 have been laminated, to thereby mold the outer
surface shape of the composite structure 18 into a predetermined
size. As the outer molds 10a and 10b, there may be used those that
meet the laminating mode of the prepreg sheets 7 like those of the
first production method.
[0112] In a fifth process (not shown), the molded composite
structure 18 is heated to a predetermined temperature to thereby
form the FRP in which the prepreg sheets 7 laminated on the core
members 6 and the prepreg sheets 7 laminated on the composite
structure 18 are integrated.
[0113] In a sixth process (see FIG. 12E), the core members 6 are
removed from the FRP to realize the robot hand member 16 having the
rib in an inner space thereof.
[0114] According to the above-mentioned production method, the
robot hand member 16 is produced such that the prepreg sheets 7 are
laminated, in a predetermined thickness, on the outer peripheral
surface of the core members 6 and the side surfaces thereof are
brought into contact with each other to form the composite
structure 18 of a rectangular shape in cross section as a whole;
the prepreg sheets 7 are laminated on the outer peripheral surface
of the composite structure 18 in a predetermined thickness, to mold
the composite structure 18 by means of the outer molds 10a and 10b;
the thus molded composite structure 18 is heated to a predetermined
temperature to form an FRP in which the prepreg sheets 7 laminated
on the core members 6 and the prepreg sheets 7 laminated on the
composite structure 18 are integrated; and the core members 6 are
removed therefrom. Thus, if a plurality of kinds of core members 6
of different sizes are prepared, it is possible to easily produce
the robot hand member 16 of predetermined size having the rib in
the inner space thereof, by arbitrarily selecting any core members
6 and by determining the numbers thereof. In this case, there is an
advantage in that no rib-constituting member 17 used in the above
first production method is required.
[0115] FIG. 13 illustrates a third method of producing the robot
hand member 16.
[0116] In a first process (see FIG. 13A), the side surfaces of a
plurality of unit constituent members 19 each of which are formed
in a hollow rectangular shape in transverse cross section and
contains a reinforcing fiber are brought into contact with each
other to form the composite structure 18 of a rectangular shape in
cross section as a whole,. The unit constituent members 19 are each
formed by, for example, cutting a plate-like FRP into~a rectangular
shape of a predetermined size and coupling the end surfaces thereof
with an adhesive. The unit constituent members 19 may further be
formed by utilizing the technology used in the above-mentioned
embodiment, i.e., by laminating the prepreg sheets on the outer
peripheral surface of the core member that is formed in a
rectangular shape in transverse cross section and is not deformed
by the heating at temperatures equal to or lower than a
predetermined temperature, and then heating to thermally set the
core member on which the prepreg sheets are laminated to the
predetermined temperature. In short, the unit constituent members
19 having a hollow rectangular shape in transverse cross section
may be formed by using any production methods.
[0117] In a second process (see FIG. 13B), the prepreg sheets 7
each containing a reinforcing fiber are adhered onto the side
surfaces of the same sides (upper and lower surfaces in the example
shown in the figure) intersecting the contact surfaces of the
composite structure 18. The cloth prepreg sheet 7d may be adhered
instead of the prepreg sheets 7.
[0118] In a third process (not shown), the composite structure 18
on which the prepreg sheets 7 are adhered is heated to a
predetermined temperature, to thereby form the FRP in which the
unit constituent members 19 and the prepreg sheets 7 are
integrated. Thus, there is realized the robot hand member 16 having
the rib in the inner space thereof.
[0119] According to the above-mentioned production method, the
robot hand member 16 is produced such that the side surfaces of the
plurality of unit constituent members 19 formed in a hollow
rectangular shape in transverse cross section are brought into
contact with each other to form the composite structure 18 a
rectangular shape in cross section as a whole; the prepreg sheets 7
are adhered onto the side surfaces of the same sides intersecting
the contact surfaces of the unit constituent members 19; and the
composite structure 18 onto which the prepreg sheets 7 are adhered
are heated, to form an FRP in which the unit constituent members 19
and the prepreg sheets 7 are integrated. Thus, if a plurality of
kinds of unit constituent members 19 having different sizes are
prepared, it is possible to easily produce the robot hand member 16
of predetermined size having the rib in the inner space thereof by
combining arbitrarily these members. In this case, the rib is
constituted by the contact surfaces of the unit constituent
members
[0120] In the second process of adhering the prepreg sheets 7 to
the composite structure 18, as shown in FIG. 13C, the prepreg
sheets 7 may be adhered by being wound on the outer peripheral
surface of the composite structure 18. In this case, since the
prepreg sheets 7 are adhered to the whole outer circumference of
the composite structure 18 constituted of a plurality of unit
constituent members 19, the steps at the contact portions appear
less conspicuously, and the robot hand member 16 exhibits favorable
appearance to boost up a commercial value. Further, a cloth prepreg
sheet may be wound on the outer peripheral surface of the composite
structure 18 on which the prepreg sheets 7 are adhered, to cover
the composite structure 18.
[0121] When the robot hand member 16 is long as shown in FIG. 14,
the base end thereof on which al large bending moment acts may be
constituted in a multiplicity of layers to suppress the deflection
due to the load at the end of the robot hand member 16. In this
case, the unit constituent members 19 are brought into contact with
one another in a multiplicity of layers to form the composite
structure 18 and, then, prepreg sheets 7 are laminated on the whole
outer surface of the composite structure 18, thereafter to be
subjected to the thermosetting. Such a technique can also be
applied to the above-mentioned second production method.
[0122] Described below are Examples and Comparative Examples of the
robot hand member in the first and second embodiments according to
the present invention.
[0123] (1) Comparative Example (Lamination of a Solid CFRP
Member):
1TABLE 1 Lamination of a solid member (CFRP plate, 12 mm thickness)
Laminating Number of Total Thickness direction lamination thickness
Kinds of prepreg (mm/sheet) (degree) (sheet) (mm) Cloth prepreg
0.25 0/90 1 0.25 Prepreg-A 0.22 0 12 2.64 (800 GPa) Prepreg-B 0.20
90 8 1.6 (240 Gpa) Prepreg-B 0.27 0 11 3.0 Prepreg-B 0.20 90 8 1.6
Prepreg-A 0.22 0 12 2.64 Cloth prepreg 0.25 0/90 1 0.25 Total 44
12.0 Deflection due to 1.6 own weight (mm) Weight (kg) 1.53
[0124] This Comparative Example deals with a robot hand member made
of the solid CFRP members described in connection with the related
art, and Table 1 shows numerical values involved in the production.
This Comparative Example uses a total of seven layers. That is,
there are used cloth prepregs in which carbon fibers are oriented
in the directions crossing the longitudinal direction at 0 degree
and 90 degrees, prepregs-A in which the pitch carbon fibers having
the tensile elasticity of 800 GPa are oriented in a direction of an
angle of 0 degree, and prepregs-B in which the PAN carbon fibers
having the tensile elasticity of 240 GPa are oriented in a
direction of an angle of 90 degrees. The cloth prepregs are
laminated on the innermost layer and on the outermost layer, and
the prepregs-A laminated in two layers and the prepegs-B laminated
in three layers are positioned between the innermost and outermost
layers. The resultant CFRP plate has a thickness of 12 mm, the
deflection due to its own weight is 1.6 mm, and the weight is 1.53
kg.
[0125] (2) Example 1 (Lamination of a Hollow CFRP Structure):
2TABLE 2 Lamination of a hollow structure (square pipe: 12 mm
thickness, CFRP plate: 2.55 mm thickness) Laminating Number of
Total Thickness direction lamination thickness Kinds of prepreg
(mm/sheet) (degree) (sheet) (mm) Cloth prepreg 0.25 0/90 1 0.25
Prepreg-A 0.22 0 5 1.1 Prepreg-B 0.20 90 6 1.2 Core member 6.9 -- 1
6.9 (aluminum et al) Prepreg-B 0.20 90 6 1.2 Prepreg-A 0.22 0 5 1.1
Cloth prepreg 0.25 0/90 1 0.25 Total 24 12.0 Deflection due to 0.47
own weight (mm) Weight (kg) 0.75 Thickness (mm) Longitudinal 12.1
(front), 11.8 (middle), 12.1 (rear) direction Width direction 12.0
(left), 11.8 (middle), 12.0 (right)
[0126] This Example 1 deals with the robot hand member 4 of a
hollow structure shown in FIG. 2 produced by the first production
method shown in FIG. 3. Table 2 shows numerical values involved in
the production. This Example uses a total of six layers. That is,
there are used cloth prepregs in which carbon fibers are oriented
in the directions crossing the longitudinal direction at 0 degree
and 90 degrees, prepregs-A in which the pitch carbon fibers having
the tensile elasticity of 800 GPa are oriented in a direction of an
angle of 0 degree, prepregs-B in which the PAN carbon fibers having
the tensile elasticity of 240 GPa are oriented in a direction of an
angle of 90 degrees, and a core member made of aluminum. The cloth
prepreg is laminated on the outer peripheral surface of the core
member as the innermost layer, the prepregs-A are laminated in two
layers thereon, the prepegs-B are laminated in two layers thereon,
and another cloth prepreg is laminated as the outermost layer. The
laminate of prepregs is thermally set, and thereafter, the core
member is removed therefrom to form a hollow structure. The
resultant CFRP plate has a thickness of 2.55 mm, the square pipe
has a thickness of 12 mm, the deflection due to its own weight is
0.47 mm, and the weight is 0.75 kg. The robot hand member has a
thickness of 11.8 mm at its central portion, which is slightly
dented compared to the thicknesses (12.0 mm, 12.1 mm) at the ends.
However, there is not any problem in supporting and conveying the
workpieces and excellent flatness can be obtained.
[0127] As compared to Comparative Example, the weight in Example 1
is decreased from 1.53 kg down to 0.75 kg and the deflection due to
the own weight is decreased from 1.6 mm down to 0.47 mm, from which
it will be understood that the robot hand member of the hollow
structure of this invention is light in weight and prevents the
deflection to a large degree. The same results are obtained even
from the robot hand member 4 produced by the second production
method.
[0128] (3) Example 2 (Lamination of a CFRP Solid Structure):
3TABLE 3 Lamination of a solid structure (square pipe: 12 mm
thickness, CFRP plate: 2.55 mm thickness, foamed urethane core
member) Laminating Number of Total Thickness direction lamination
thickness Kinds of prepreg (mm/sheet) (degree) (sheet) (mm) Cloth
prepreg 0.25 0/90 1 0.25 Prepreg-A 0.22 0 5 1.1 Prepreg-B 0.20 90 6
1.2 Core member 6.9 -- 1 6.9 (foamed urethane) Prepreg-B 0.20 90 6
1.2 Prepreg-A 0.22 0 5 1.1 Cloth prepreg 0.25 0/90 1 0.25 Total 24
12.0 Deflection due to 0.57 own weight (mm) Weight (kg) 1.06
Thickness (mm) Longitudinal 12.0 (front), 12.0 (middle), 12.0
(rear) direction Width direction 12.0 (left), 12.0 (middle), 12.0
(right)
[0129] This Example 2 deals with the robot hand member 14 of a
solid structure shown in FIG. 7 produced by the first production
method. Table 3 shows numerical values involved in the production.
This Example uses a total of six layers. That is, there are used
cloth prepregs in which carbon fibers are oriented in the
directions crossing the longitudinal direction at 0 degree and 90
degrees, prepregs-A in which the pitch carbon fibers having the
tensile elasticity of 800 GPa are oriented in a direction of an
angle of 0 degree, prepregs-B in which the PAN carbon fibers having
the tensile elasticity of 240 GPa are oriented in a direction of an
angle of 90 degrees, and a core member made of a light-weight
material of foamed urethane. The cloth prepreg is laminated on the
outer peripheral surface of the core member as the innermost layer,
the prepregs-A are laminated in two layers thereon, the prepegs-B
are laminated in two layers thereon, and another cloth prepreg is
laminated as the outermost layer. The laminate of prepregs is
thermally set with the core member being left therein. The
resultant CFRP plate has a thickness of 2.55 mm, the square pipe
has a thickness of 12 mm, the deflection due to its own weight is
0.57 mm and the weight is 1.06 kg. The robot hand member has a
thickness of (12.0 mm) which is the same even at the end portions
and at its central portion, from which it will be understood that
this robot hand member is superior concerning the flatness to the
robot hand member of the hollow structure of Example 1.
[0130] As compared to Comparative Example, the weight in Example 2
is decreased from 1.53 kg down to 1.06 kg and the deflection due to
the own weight is decreased from 1.6 mm down to 0.57 mm, from which
it will be understood that the robot hand member of the solid
structure of this invention, too, is light in weight and prevents
the deflection to a high degree compared to the robot hand member
produced by using the CFRP solid material. The same results are
obtained even from the robot hand member 14 produced by the second
production method.
[0131] The entire contents of Japanese Patent Application Nos.
2001-97478 and 2001-97479 filed on Mar. 29, 2001, respectively, and
Japanese Patent Application No. 2001-115215 filed on Apr. 13, 2001,
priorities of which are claimed, are incorporated herein by
reference.
* * * * *