U.S. patent application number 11/932305 was filed with the patent office on 2008-04-24 for industrial robot.
This patent application is currently assigned to Kabushiki Kaisha Yaskawa Denki. Invention is credited to Kazuhiro HANIYA, Manabu OKAHISA, Tomoyuki SHIRAKI, Keisuke YONEHARA.
Application Number | 20080092689 11/932305 |
Document ID | / |
Family ID | 19146870 |
Filed Date | 2008-04-24 |
United States Patent
Application |
20080092689 |
Kind Code |
A1 |
SHIRAKI; Tomoyuki ; et
al. |
April 24, 2008 |
INDUSTRIAL ROBOT
Abstract
There is provided an industrial robot having no interference of
a cable for an end effector or the like with a peripheral
apparatus. An end effector 5 is fixed to a wrist flange 4 through
an intermediate member 6. The intermediate member 6 takes the shape
of a crankshaft in which a first flange 6a attached directly to the
wrist flange 4, a second flange 6b provided at a predetermined
interval in parallel with the first flange 6a and attached directly
to the end effector 5, and two members 6c and 6d for coupling the
first and second flanges 6a and 6b are arranged symmetrically.
Inventors: |
SHIRAKI; Tomoyuki; (Fukuoka,
JP) ; OKAHISA; Manabu; (Fukuoka, JP) ;
YONEHARA; Keisuke; (Fukuoka, JP) ; HANIYA;
Kazuhiro; (Fukuoka, JP) |
Correspondence
Address: |
SUGHRUE-265550
2100 PENNSYLVANIA AVE. NW
WASHINGTON
DC
20037-3213
US
|
Assignee: |
Kabushiki Kaisha Yaskawa
Denki
Fukuoka
JP
|
Family ID: |
19146870 |
Appl. No.: |
11/932305 |
Filed: |
October 31, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10493694 |
Apr 27, 2004 |
7322258 |
|
|
PCT/JP02/11184 |
Oct 28, 2002 |
|
|
|
11932305 |
Oct 31, 2007 |
|
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Current U.S.
Class: |
74/490.02 ;
901/28 |
Current CPC
Class: |
B25J 19/0025 20130101;
Y10T 74/20311 20150115; Y10T 74/20329 20150115 |
Class at
Publication: |
074/490.02 ;
901/028 |
International
Class: |
B25J 17/00 20060101
B25J017/00; B25J 17/02 20060101 B25J017/02; B25J 18/00 20060101
B25J018/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 29, 2001 |
JP |
2001-331263 |
Claims
1. An industrial robot comprising: an arm; a wrist portion provided
on a tip of the arm; an intermediate member; an end effector
attached to a tip of the wrist portion through the intermediate
member; a cable provided from the arm to the end effector for
supplying a power, a signal or a material to the end effector; and
a cylindrical member, wherein the wrist portion comprises: a wrist
base which rotates around a longitudinal axis of the arm; and a
fixing member which rotates integrally with the wrist base and is
attached to the wrist base, wherein the cable is clamped onto the
arm, wound upon the arm around the longitudinal axis of the arm,
bent in a U shape so as to change a direction thereof, wound upon
the arm in a reverse direction, and clamped onto the fixing member,
and the cylindrical member covers the arm and a portion of the
cable that is wound on the arm.
2. An industrial robot comprising: an arm; a wrist portion provided
on a tip of the arm; an intermediate member; an end effector
attached to a tip of the wrist portion through the intermediate
member; and a cable provided from the arm to the end effector for
supplying a power, a signal or a material to the end effector,
wherein the wrist portion comprises: a wrist base which rotates
around a longitudinal axis of the arm; and a fixing member which
rotates integrally with the wrist base and is attached to the wrist
base, wherein the cable is clamped onto the arm, wound upon the arm
around the longitudinal axis of the arm, bent in a U shape so as to
change a direction thereof, wound upon the arm in a reverse
direction, clamped onto the fixing member, and extended to the end
effector, and the cable is constituted by two portions and the two
portions are coupled at the fixing member.
3. The industrial robot according to claim 1, wherein the cable is
clamped onto the arm on one side of the arm, and is wound upon the
arm around the longitudinal axis of the arm and toward the other
side of the arm,
4. The industrial robot according to claim 2, wherein the cable is
clamped onto the arm on one side of the arm, and is wound upon the
arm around the longitudinal axis of the arm and toward the other
side of the arm.
5. The industrial robot according to claim 2, wherein the two
portions are separate members.
6. The industrial robot according to claim 4, wherein the two
portions are separate members.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of and claims the benefit
of priority under 35 U.S.C. .sctn.120 from U.S. Ser. No.
10/493,694, filed Apr. 27, 2004, and claims the benefit of priority
under 35 U.S.C. .sctn. 119 from Japanese Patent Application No.
2001-331263, filed Oct. 29, 2001, the entire contents of each which
are incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to an industrial robot and
more particularly to a vertical articulated robot for spot
welding.
BACKGROUND ART
[0003] FIG. 4 is a side view showing a conventional spot welding
robot. In FIG. 4, 51 denotes a 6-axis vertical articulated robot,
52 denotes a spot welding gun attached to the tip of the vertical
articulated robot 51, and 53 denotes a cable for supplying a
welding current to the spot welding gun.
[0004] The vertical articulated robot 51 includes a fixing portion
54, a turning portion 55 supported pivotally on the fixing portion
54 and turned around a vertical axis, a lower arm 56 supported
pivotally on the turning portion 55 and rocked in a longitudinal
direction, an upper arm 57 supported pivotally on the lower arm 56
and rocked in a vertical direction, and a wrist portion 58 attached
to the tip of the upper arm 57. The wrist portion 58 has the degree
of freedom of a rotation around three axes which are orthogonal to
each other and has the spot welding gun 52 fixed to a tip
thereof
[0005] The cable 53 is wired from a welding timer, which is not
shown, to the fixing portion 54 and is clamped onto the fixing
portion 54 where said cable is wound around the vertical axis (in a
counterclockwise direction seen from above) at the level of the
fixing portion 54 and rises up to the level of the turning portion
55. Furthermore, the cable 53 is wound around the vertical axis (in
a clockwise direction seen from above) at the level of the turning
portion 55 and is clamped onto the turning portion 55. Furthermore,
the cable 53 rises upward along the lower arm 56, and is hung on a
cable stand 59 fixed onto the upper arm 57 and is extended to the
spot welding gun 52.
[0006] In the conventional spot welding robot, however, the cable
53 is lifted dynamically above the upper arm 57 with providing
certain looseness. Therefore, there is a problem in that the cable
53 interferes with a peripheral apparatus or the like. Moreover,
there is a problem in that the cable 53 is rubbed with the
peripheral apparatus or the like and is thus worn out. Furthermore,
there is also a problem in that the operation of the wrist portion
58 is limited if the looseness of the cable is decreased to avoid
the interference with the peripheral apparatus or the like.
[0007] Although the cable 53 provided to have the looseness above
the upper arm 57 is rocked according to the operation of the robot
where said rocking motion is difficult to be predicted with
accuracy. Therefore, another problem is that the interference of
the cable with the peripheral apparatus cannot be checked in the
simulation such as by offline teaching.
DISCLOSURE OF THE INVENTION
[0008] Therefore, it is an object of the invention to provide an
industrial robot having no interference of a cable for an end
effector or the like with a peripheral apparatus.
[0009] In order to solve the problems, the invention provides an
industrial robot in which an end effector is attached to a tip of a
wrist portion provided on a tip of an arm, and a cable or the like
for supplying a power, a signal or a material to the end effector
is provided from the arm to the end effector, wherein the end
effector is fixed to the wrist portion through an intermediate
member, and the intermediate member is formed in a shape of a
crankshaft in which a first flange attached directly to the wrist,
a second flange provided at a predetermined interval in parallel
with the first flange and attached directly to the end effector,
and two members provided in a position placed apart from centers of
the first and second flanges and serving to couple the first and
second flanges are arranged symmetrically. Moreover, the wrist
portion includes a wrist base rotated axially in a longitudinal
direction of the arm and a fixing member attached to the wrist base
and rotated integrally with the wrist base, clamps the cable or the
like onto the arm and winds the cable or the like upon the arm
axially in the longitudinal direction of the arm, further bends the
cable or the like to be U-shaped and changes a direction thereof,
winds the cable or the like upon the arm in a reverse direction and
clamps the cable or the like onto the fixing member, and further
extends the cable or the like to the end effector. Furthermore, the
cable or the like is divided into two portions and the two portions
are coupled through a connector attached to the fixing member. In
addition, a portion of the cable or the like which is wound upon
the arm is covered with a cylindrical member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a plan view showing an upper arm of an industrial
robot according to an embodiment of the invention;
[0011] FIG. 2 is a side view of the upper arm of an industrial
robot shown in FIG. 1;
[0012] FIG. 3 is an explanatory view showing an intermediate member
seen in an AA' line of FIG. 1; and
[0013] FIG. 4 is a side view showing a spot welding robot according
to the conventional art.
[0014] FIG. 5 shows the cable being made of two portions with a
connector.
BEST MODE FOR CARRYING OUT THE INVENTION
[0015] In embodiment of the invention will be described below with
reference to the drawings. FIG. 1 is a plan view showing the upper
arm of an industrial robot according to the embodiment of the
invention and FIG. 2 is a side view showing the same, a part of
which is shown in a section for convenience of explanation.
[0016] In the drawing, 1 denotes the upper arm of a so-called
6-axis vertical articulated robot. The tip of the upper arm 1
includes a wrist portion having a wrist base portion 2 to be
rotated around a first wrist axis 21 in the longitudinal direction
of the upper arm 1, a wrist rocking member 3 to be rocked around a
second wrist axis 22 which is orthogonal to the first wrist axis,
and a wrist flange 4 to be rotated around a third wrist axis 23
which is orthogonal to the second wrist axis 22.
[0017] 5 denotes a spot welding gun which is an end effector fixed
to the wrist flange 4 through an intermediate member 6. The
intermediate member 6 is constituted by a first flange 6a fixed
directly to the wrist flange 4, a second flange 6b provided at a
predetermined interval in parallel with the first flange 6a and
serving to directly fix the spot welding gun 5, and connecting
members 6c and 6d for coupling the first flange 6a to the second
flange 6b. The connecting members 6c and 6d are provided in
parallel with each other symmetrically with respect to the third
wrist axis 23 in the side view (FIG. 2), and furthermore, they are
offset to either side with respect to the third wrist axis 23 in
the plan view (FIG. 1). Because of such a structure, the
intermediate member 6 takes the shape of a crank in the plan view
(FIG. 1).
[0018] 7 denotes a welding cable which is a wiring and piping
bundle for supplying a welding current, a power for gun driving,
cooling water, an operation signal or the like to the spot welding
gun 5. 8 denotes a first fixing member fixed to the wrist base 2
and rotated around the first wrist axis 21 integrally with the
wrist base 2, and 9 denotes a second fixing member fixed to the
wrist rocking member 3.
[0019] In the same manner as in the example according to the
conventional art, the welding cable 7 is extended to the upper arm
1 from a welding timer which is not shown through the fixing
portion, the turning portion and the lower arm of the robot, is
fixed onto the upper surface of the upper arm 1 through a clamp 10,
is wound clockwise (as seen from the wrist side) around the upper
arm 2 taking a cylindrical shape and reaches the lower surface of
the upper arm 1. The welding cable 7 is bent like a U shape at the
lower surface of the upper arm 1, is then wound in a reverse
direction, that is, a counterclockwise direction around the upper
arm 1, reaches the upper surface of the upper arm 1 again, is fixed
to the first fixing member 8 through clamps 11 and 12, passes
through the side of the wrist rocking member 3 and is fixed to the
second fixing member 9 through a clamp 13. When taking a posture
shown in FIGS. 1 and 2, that is, such a posture that the first
wrist axis 21 and the third wrist axis 23 are coaxial with each
other, the first fixing member 8 and the second fixing member 9 are
attached in such a manner that the clamp 12, the center of the
second wrist axis 22 and the clamp 13 are arranged on a straight
line. Furthermore, the welding cable 7 reaches the spot welding gun
5 through a portion between the connecting members 6c and 6d of the
intermediate member 6 and is fixed to the spot welding gun 5
through a clamp 14.
[0020] 15 denotes a guide member. The guide member 15 is a
cylindrical member in concentric with the upper arm 1 (a section
thereof is shown in the drawing), and serves to cover a portion of
the welding cable 7 which is wound upon the upper arm 1 (a portion
from the clamp 10 to the clamp 11), thereby holding the welding
cable 7 in a doughnut-shaped space between the upper arm 1 and the
guide member 15.
[0021] When the wrist base 2 is rotated around the first wrist axis
21, the welding cable 7 is guided by the guide member 15 and
follows the motion of the wrist base 2 by a moving bend on a
circumference around the upper arm 1 (an operation in which one of
the portions is wound upon the upper arm 1 so as to be long and the
other portion is wound to be short with a U-shaped bent portion set
to be a boundary).
[0022] When the wrist rocking member 3 is rocked around the second
wrist axis 22, the welding cable 7 follows the motion of the wrist
rocking member 3 by a bend between the clamp 12 and the clamp 13.
At this time, since the welding cable 7 is bent in almost the same
plane, there is a small danger that it might come in contact with a
peripheral apparatus or the like or might be caught thereon.
[0023] FIG. 3 is an explanatory view showing the intermediate
member 6 seen in an AA' line of FIG. 1. As shown in FIG. 3, the
welding cable 7 fixed to the wrist rocking member 3 (not shown)
through the clamp 13 passes through the center of the third wrist
axis 23 from below the intermediate member 6, and furthermore,
passes through a portion between the connecting members 6c and 6d
to come upward out of the intermediate member 6 and is fixed to the
spot welding gun 5 (not shown) through the clamp 14. Since the
welding cable 7 is thus provided, the welding cable 7 is bent in
the intermediate member 6 to follow the rotation of the wrist
flange 4 around the third wrist axis 23 when the wrist flange 4 is
rotated around the third wrist axis 23.
[0024] The connecting members 6c and 6d are provided with an offset
from the third wrist axis 23 and the intermediate member 6 is
caused to take the shape of a crankshaft in order to avoid the
interference of the connecting members 6c and 6d with the welding
cable 7 and to maintain the operating range of the wrist flange 4
around the third wrist axis 23.
[0025] Moreover, the second fixing member 9 does not need to be
provided. In some cases in which the welding cable 7 is not fixed
to the wrist rocking member 3 depending on the axial structure of
the wrist portion (for example, a center distance) or the rigidity
of the welding cable 7, the followability of the welding cable for
the operation of the wrist portion can be more excellent.
[0026] In place of the clamp 14, moreover, the welding cable 7 may
be fixed at the upper portion of the intermediate member 6 (which
is indicated as the designation F in FIG. 3).
[0027] If the welding cable 7 is cut between the clamp 11 and the
clamp 12 and is thus divided into two portions 7a and 7b to be
connected through a connector 70, and the connector is fixed to the
first fixing member 8, furthermore, the spot welding gun 5 can be
repaired and exchanged conveniently.
[0028] While the spot welding robot has been taken in the
description of the embodiment, the invention is not restricted to
the spot welding robot but can be applied to many uses such as
painting, sealing, abrasion and handling. In other words, the end
effector may be a spray gun for painting, a nozzle for sealing, an
abrading tool, a mechanical hand or the like, and a cable or the
like may be a hose for painting, a sealant supply hose, an air hose
for driving a pneumatic tool, a power line for driving a power tool
or the like.
[0029] As described above, according to the invention, the cable
for the end effector or the like is provided along the upper arm
and the wrist. Therefore, it is possible to prevent the
interference of the cable or the like with the peripheral apparatus
or the like, and furthermore, it is possible to obtain such an
advantage as to prevent the damage of the cable or the like from
being caused by the interference.
[0030] Moreover, the motion of the cable or the like with respect
to the upper arm is restricted to a constant space. In a simulation
such as offline teaching, therefore, it is also possible to obtain
such an advantage that the interference of the cable or the like
with the peripheral apparatus or the like can easily be
checked.
[0031] Industrial Applicability
[0032] The invention is useful as an industrial robot and more
particularly as a vertical articulated robot for spot welding.
* * * * *