U.S. patent application number 12/778433 was filed with the patent office on 2010-12-16 for roller hemming apparatus and roller hemming method.
This patent application is currently assigned to HONDA MOTOR CO., LTD.. Invention is credited to Toru Kumagai, Fujio Motoki.
Application Number | 20100313621 12/778433 |
Document ID | / |
Family ID | 43070057 |
Filed Date | 2010-12-16 |
United States Patent
Application |
20100313621 |
Kind Code |
A1 |
Kumagai; Toru ; et
al. |
December 16, 2010 |
ROLLER HEMMING APPARATUS AND ROLLER HEMMING METHOD
Abstract
A roller hemming apparatus includes: a cylindrical roller
supported rotatably on a main body; a first position adjusting
mechanism for adjusting a first position of the roller in a
direction which is perpendicular to a rotating axis direction
thereof; a second position adjusting mechanism for adjusting a
second position of the roller in the rotating axis direction; and a
control unit for controlling the first and second position
adjusting mechanisms. The control unit adjusts the first position
by controlling the first position adjusting mechanism to abut the
roller with a third position which is apart from a bending point of
the flange, and the control unit adjusts the second position by
detecting a load acting on the roller in an axial direction thereof
as a drive load, calculating a difference between the drive load
and a given master load, and controlling the second position
adjusting mechanism according to the difference.
Inventors: |
Kumagai; Toru; (Hagagun,
JP) ; Motoki; Fujio; (Hagagun, JP) |
Correspondence
Address: |
RANKIN, HILL & CLARK LLP
38210 GLENN AVENUE
WILLOUGHBY
OH
44094-7808
US
|
Assignee: |
HONDA MOTOR CO., LTD.
Tokyo
JP
|
Family ID: |
43070057 |
Appl. No.: |
12/778433 |
Filed: |
May 12, 2010 |
Current U.S.
Class: |
72/220 |
Current CPC
Class: |
G05B 19/188 20130101;
B21D 39/023 20130101; B21D 39/021 20130101 |
Class at
Publication: |
72/220 |
International
Class: |
B21D 7/022 20060101
B21D007/022 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 12, 2009 |
JP |
2009-140977 |
Claims
1. A roller hemming apparatus for hemming a flange formed on a
workpiece, comprising: a main body; a cylindrical roller supported
rotatably on the main body; a first position adjusting mechanism
for adjusting a first position of the roller with respect to a
direction which is perpendicular to a rotating axis direction of
the roller; a second position adjusting mechanism for adjusting a
second position of the roller with respect to the rotating axis
direction; and a control unit for controlling the first position
adjusting mechanism and the second position adjusting mechanism,
wherein the control unit adjusts the first position of the roller
by controlling the first position adjusting mechanism to bring the
roller into abutment with a third position which is spaced by a
given distance apart from a bending point of the flange, and
wherein the control unit adjusts the second position of the roller
by detecting a load acting on the roller in an axial direction of
the roller as a drive load, calculating a difference between the
drive load and a given master load, and controlling the second
position adjusting mechanism according to the difference.
2. The roller hemming apparatus according to claim 1, wherein when
the drive load is larger than the master load, the control unit
controls the second position adjusting mechanism so as to position
the roller in a direction in which the flange is bent largely.
3. A roller hemming method for hemming a flange formed on a
workpiece, comprising: providing a roller hemming apparatus
including: a main body; a cylindrical roller supported rotatably on
the main body; a first position adjusting mechanism for adjusting a
first position of the roller with respect to a direction which is
perpendicular to a rotating axis direction of the roller; and a
second position adjusting mechanism for adjusting a second position
of the roller with respect to the rotating axis direction;
adjusting the first position of the roller by controlling the first
position adjusting mechanism to bring the roller into abutment with
a third position which is spaced by a given distance apart from a
bending point of the flange; detecting a load acting on the roller
in an axial direction of the roller as a drive load; calculating a
difference between the drive load and a given master load; and
adjusting the second position of the roller by controlling the
second position adjusting mechanism according to the
difference.
4. The roller hemming method according to claim 3, wherein when the
drive load is larger than the master load, the roller is positioned
in a direction in which the flange is bent largely by controlling
the second position adjusting mechanism.
Description
[0001] This application claims priority from Japanese Patent
Application No. 2009-140977, filed on Jun. 12, 2009, the entire
contents of which are hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present disclosure relates to a roller hemming apparatus
and a roller hemming method, and more particularly to a roller
hemming apparatus and a roller hemming method for hemming a flange
which is formed on a workpiece.
DESCRIPTION OF RELATED ART
[0003] Body panels of a motor vehicle such as a door panel, a side
panel or a hood are made up of an outer panel and an inner panel
which are integrated with each other.
[0004] A process of integrating an outer panel and an inner panel
includes, for example, a marriage step of superposing an inner
panel on an outer panel having a flange formed so as to extend
upwards and a hemming step of bending the flange of the outer panel
inwards thereof by a roller hemming apparatus.
[0005] Japanese Patent Application Publication No. JP-A-2008-023587
discloses a related-art roller hemming apparatus including a main
body, a roller supported rotatably on the main body, and a moving
mechanism provided on the main body for moving the roller in a
direction of a rotating axis thereof.
[0006] In the related-art roller hemming apparatus, a position of
the roller in the rotating axis direction is adjusted in advance
according to property of the outer panel. Then, by moving the
roller hemming apparatus along an end edge of the outer panel, the
flange of the outer panel is pressed by the roller so as to bend
the flange inwards of the outer panel.
[0007] Incidentally, there may be caused a slight variation in
material or height of flanges of outer panels used in the hemming
step described above lot by lot. As this occurs, since deformation
resistance of flanges varies, a spring-back amount of resulting
hemmed flanges also varies, leading to vary angles of hemmed
flanges.
SUMMARY OF INVENTION
[0008] Illustrative aspects of the present invention provide a
roller hemming apparatus in which a flange shape of a workpiece
after hemming can be constant, and a roller hemming method.
[0009] According to a first aspect of the invention, a roller
hemming apparatus for hemming a flange formed on a workpiece,
comprising: a main body; a cylindrical roller supported rotatably
on the main body; a first position adjusting mechanism for
adjusting a first position of the roller with respect to a
direction which is perpendicular to a rotating axis direction of
the roller; a second position adjusting mechanism for adjusting a
second position of the roller with respect to the rotating axis
direction; and a control unit for controlling the first position
adjusting mechanism and the second position adjusting mechanism,
wherein the control unit adjusts the first position of the roller
by controlling the first position adjusting mechanism to bring the
roller into abutment with a third position which is spaced by a
given distance apart from a bending point of the flange, and
wherein the control unit adjusts the second position of the roller
by detecting a load acting on the roller in an axial direction of
the roller as a drive load, calculating a difference between the
drive load and a given master load, and controlling the second
position adjusting mechanism according to the difference
[0010] Other aspects and advantages of the invention will be
apparent from the following description, the drawings and the
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is an overall perspective view showing a roller
hemming system using a roller hemming apparatus according to an
exemplary embodiment of the invention;
[0012] FIG. 2 is an enlarged perspective view showing a working
table of the roller hemming system;
[0013] FIG. 3 is a perspective view showing the roller hemming
apparatus;
[0014] FIG. 4 is a diagram showing a configuration of a control
means of the roller hemming apparatus;
[0015] FIG. 5 is a flowchart showing operations for adjusting a
position of a hemming roller of the roller hemming apparatus with
respect to a rotating axis direction;
[0016] FIG. 6 is a diagram showing an operation in which the
hemming roller of the roller hemming apparatus is brought into
abutment with a flange or a workpiece;
[0017] FIG. 7 is another diagram showing an operation in which the
hemming roller of the roller hemming apparatus is brought into
further abutment with the flange of the workpiece; and
[0018] FIG. 8 is a further diagram showing an operation in which
the hemming roller of the roller hemming apparatus is brought into
still further abutment with the flange of the workpiece.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0019] Hereinafter, an exemplary embodiment of the invention will
be described based on the drawings.
[0020] FIG. 1 is an overall perspective view showing a roller
hemming system 1 using a roller hemming apparatus 10 according to
an exemplary embodiment of the invention.
[0021] The roller hemming system 1 includes a working table 30 on
which an outer panel 20 as a workpiece is placed, a robot 40 placed
in a vicinity of the working table 30, and a controller 50 for
controlling the robot 40.
[0022] The outer panel 20 is such as to be formed by bending a
panel and includes a flat plate-like base portion 21 and a flange
22 which is formed on a circumferential edge of the base portion
21.
[0023] FIG. 2 is an enlarged perspective view showing the working
table 30.
[0024] The working table 30 includes a support 31 (FIG. 1) provided
on a floor and a die 32 supported on the support 31.
[0025] A circumferential edge portion of an upper face of the die
32 is made higher than a central portion thereof, whereby a riser
plane 321 is formed along the circumferential edge portion. The
outer panel 20 is disposed so that the flange 22 is brought into
abutment with the riser plane 321.
[0026] A groove 322 is formed on a lower face of the die 32 so as
to extend along the circumferential edge portion. Accordingly, the
groove 322 is made parallel to a direction in which the flange 22
of the outer panel 20 extends.
[0027] The robot 40 includes a base portion 41 fixed to the floor
and a robot arm 42 which is provided on the base portion 41 for
adjusting a position and a posture of the roller hemming apparatus
10 in a three-dimensional space.
[0028] FIG. 3 is a perspective view showing the roller hemming
apparatus 10.
[0029] The roller hemming apparatus 10 is attached to a distal-end
flange 42a of the robot arm 42. The roller hemming apparatus 10
includes a main body 11, a hemming roller 12 as a cylindrical
roller supported rotatably on the main body 11, a pressing
mechanism 13 as a first position adjusting mechanism which is
provided on the main body 11 for adjusting a position of the
hemming roller 12 in a direction which is perpendicular to a
rotating axis direction thereof, and a pushing mechanism 14 as a
second position adjusting mechanism which is provided on the main
body 11 for adjusting a position of the hemming roller 12 in the
rotating axis direction.
[0030] The main body 11 includes an outer housing 15 in which an
elongated hole portion 15a is formed, a hemming roller supporting
portion 16 which projects from the hole portion 15a in the outer
housing 15 to support rotatably the hemming roller 12, the pushing
mechanism 14 for adjusting a position of the hemming roller
supporting portion 16, a circular disc-like guide roller 17 which
is provided so as to confront the hemming roller 12, and a roller
supporting portion 18 which projects from the hole portion 15a in
the outer housing 15 to support rotatably the guide roller 17.
[0031] The guide roller supporting portion 18 includes a supporting
portion main body 18a for supporting the guide roller 17 rotatably
and an arm 18b which projects from the hole portion 15a in the
outer housing 15 to support the supporting portion main body 18a
rotatably about a rotating axis which is directed perpendicular to
the rotating axis of the hemming roller 12. Accordingly, a rotating
axis of the guide roller 17 becomes parallel to the rotating axis
of the hemming roller 12 or is inclined relative to the rotating
axis of the hemming roller 12.
[0032] A distal end face 121 of the hemming roller 12 is chamfered
so as to have two tapering surfaces as the first position adjusting
mechanism (refer to FIG. 6). The two tapering surfaces are made up
of a first tapering surface 122 which is formed on a distal end
side of the hemming roller 12 and a second tapering surface 123
which is formed closer to a proximal end side of the hemming roller
12 than the first tapering surface 122 and whose inclination angle
relative to the rotating axis is smaller than that of the first
tapering surface 122.
[0033] The rotating axis of the hemming roller 12 extends in a
direction in which the hemming roller 12 projects from or retreats
into the hole portion 15a in the outer housing 15.
[0034] The pushing mechanism 14 includes a servo motor 141, a ball
screw connected to a rotating shaft (not shown) of the servo motor
141, a nut portion, not shown, which is fixed to the hemming roller
supporting portion 16 and which screws on the ball screw, a load
detection sensor 142 for detecting a torque as a drive load acting
on the servo motor 141, and a position detection sensor 143 for
detecting an axial position of the hemming roller 12.
[0035] This pushing mechanism 14 moves the hemming roller
supporting portion 16 in the direction in which the hemming roller
supporting portion 16 projects from or retreats into the outer
housing 15 by driving the servo motor 141 to rotate the ball screw.
Namely, the pushing mechanism 14 moves the hemming roller
supporting portion 16 along the rotating axis direction of the
hemming roller 12.
[0036] The pressing mechanism 13 adjusts a space between the
hemming roller 12 and the guide roller 17 by moving at least one of
the hemming roller supporting portion 16 and the guide roller
supporting portion 18.
[0037] The guide roller 17 can fit in the groove 322 provided in
the die 32 at a circumferential edge thereof.
[0038] FIG. 4 is a diagram showing a configuration of the
controller 50.
[0039] The controller 50 is provided with a Central Processing Unit
(CPU) for processing various functions, and a memory for storing
tables which stores data and programs which executes various
functions. The controller 50 controls the robot arm 42 of the robot
40 and also controls the roller hemming apparatus 10.
[0040] The controller 50 includes an arm control unit 51 for
controlling the robot arm 42 of the robot, a pressure control unit
52 for controlling the pressing mechanism 13, a position command
value data table 53 for storing a command value for a position of
the hemming roller 12 with respect to the rotating axis direction
thereof as a position command value, a pushing control unit 54 for
controlling the servo motor 141 of the pushing mechanism 14 based
on the position command value stored in the position command value
data table 53, a master load data table 55 for storing a torque
reference value as a master load, a differential load calculation
unit 56 for calculating a difference between a toque detected by
the load detection sensor 142 and the torque reference value stored
in the master load data table 55, a position command value
calculation unit 57 for calculating a position command value
according to the difference calculated at the differential load
calculation unit 56, a position command value changing unit 58 for
causing the position command value calculated at the position
command value calculation unit 57 to be stored in the position
command value data table 53, and a master load changing unit 59 for
calculating a new torque reference value according to the
difference calculated at the differential load calculation unit 56
to store the new torque reference value in the master load data
table 55.
[0041] The pushing control unit 54 reads out the position command
value stored in the position command value data table 53 and
controls a current to be supplied to the servo motor 14 while
monitoring the position of the hemming roller 12 by the position
detection sensor 143 so that the hemming roller 12 is located in a
given position which matches the position command value.
[0042] The differential load calculation unit 56 calculates a
torque difference by reading out the torque reference value stored
in the master load data table 55 and subtracting the torque
reference value from the torque detected by the load detection
sensor 142.
[0043] The position command value calculation unit 57 increases the
position command value in the rotating axis direction of the
hemming roller 12 when the difference calculated by the
differential load calculation unit 56 is positive.
[0044] Namely, when the torque detected by the load detection
sensor 142 is larger than the torque reference value, it is
determined that the deformation resistance of the outer panel 20 is
large, and then the position command value calculation unit 57
increases the position command value so as to cause the hemming
roller 12 to project from the outer housing 15.
[0045] When the torque detected by the load detection sensor 142 is
larger than the torque reference value, that is, when the
difference calculated by the differential load calculation unit 56
is positive, the master load changing unit 59 sets the torque
detected by the load detection sensor 142 as a new torque reference
value and causes the new torque reference value to be stored in the
master load data table 55.
[0046] FIG. 5 is a flowchart showing operations for adjusting the
position of the hemming roller 12 in the rotating axis direction
thereof.
[0047] In step S1, the pushing control unit 54 reads out the
position command value stored in the position command value data
table 53. Then, by controlling the current that is supplied to the
servo motor 141 provided in the pushing mechanism 14 so that the
hemming roller 12 is located in the given position which matches
the position command value, the hemming roller 12 is caused to move
towards the given position in the rotating axis direction
thereof.
[0048] In step S2, the pushing control unit 54 determines whether
or not the position of the hemming roller 12 detected by the
position detection sensor 143 has reached the given position.
[0049] If the determination is YES, the flow of operations proceeds
to step S4, whereas if the determination is NO, the flow of
operations proceeds to step S3.
[0050] In step S3, the pushing control unit 54 increases the
current to be inputted into the servo motor 141 provided in the
pushing mechanism 14, and the flow of operations returns to step
S1.
[0051] In step S4, since the hemming roller 12 has reached the
given position which matches the position command value, the
differential load calculation unit 56 calculates a difference
between the torque detected by the load detection sensor 142 and
the torque reference value stored in the master load data table
55.
[0052] In step S5, the position command value calculation unit 57
determines whether or not the difference calculated at the
differential load calculation unit 55 is positive. If the
determination is YES, the flow of operations proceeds to step S6,
whereas if the determination is NO, the flow of operations
ends.
[0053] In step S6, since the difference calculated at the
differential load calculation unit 56 is positive, it is determined
that the deformation resistance of the outer panel 20 is high, and
then the position command value calculation unit 57 increases the
position command value, and the position command value changing
unit 58 causes the increased position command value to be stored in
the position command value data table 53.
[0054] In step S7, the master load changing unit 59 sets the torque
detected by the load detection sensor 142 as a new torque reference
value and causes the new torque reference value to be stored in the
master load data table 55, and the flow of operations returns to
step S1.
[0055] Next, the operation of the roller hemming system 1 will be
described.
[0056] The roller hemming system 1 will operates as will be
described below.
[0057] In an initial state, the outer panel 20 is disposed on the
die 32 so that the flange 22 is in abutment with the riser plane
321. Note that an inner panel, not shown, is disposed on the outer
panel 20.
[0058] First, the robot arm 42 of the robot 40 is controlled by the
arm control unit 51 of the controller 50 so that the roller hemming
apparatus 10 approaches the working table 30 so as to allow the
guide roller 17 of the roller hemming apparatus 10 to fit in the
groove 322 on the lower face of the die 32.
[0059] Next, the pressing mechanism 13 is controlled by the
pressure control unit 52 of the controller 50 so that the space
between the hemming roller 12 and the guide roller 17 gets narrower
so as to allow the hemming roller 12 to be disposed on the
circumferential edge portion on the upper face of the die 32.
[0060] Next, the hemming roller 12 is caused to project from the
outer housing 15 by the pushing mechanism 14, and as shown in FIG.
6, the distal end face 121 of the hemming roller 12 is brought into
abutment with the flange 22 of the outer panel 20.
[0061] Next, the hemming roller 12 is caused to further project
from the outer housing 15 by the pushing mechanism 15, and as shown
in FIG. 7, a corner portion between the distal end face 121 of the
hemming roller 12 and the first tapering surface 122 is brought
into abutment with the flange 22 of the outer panel 20 so as to
press the flange 22. The abutment position of the hemming roller 12
is located in a position which is spaced by a given distance
B.sub.1 apart from a bending point A of the flange 22.
[0062] Next, when the guide roller 17 moves along the groove 322,
the hemming roller apparatus 10 moves along the flange 22. Then,
the flange 22 is pressed to be bent by the hemming roller 12.
[0063] The position of the hemming roller 12 is adjusted with
respect to the rotating axis direction thereof while the hemming
roller apparatus 10 moves along the flange 22.
[0064] Specifically, following the flowchart described above, it is
determined whether or not the torque of the servo motor 141 is
larger than the given torque reference value. If it is determined
that the torque of the servo motor 141 is larger than the given
torque reference value, the position of the hemming roller 12 is
adjusted so that the hemming roller 12 projects from the outer
housing 15. Namely, the hemming roller 12 is caused to project
further from the outer housing 15 by the pushing roller 14, and as
shown in FIG. 8, a corner portion between the first tapering
surface 122 and the second tapering surface 123 is brought into
abutment with the flange 22 of the outer panel 20 so as to press
the flange 22.
[0065] Accordingly, the hemming roller 12 is positioned in a
direction in which the flange 22 is bent largely. A distance
between the abutment position of the hemming roller 12 and the
bending point A becomes shorter B.sub.2 than the given distance
B.sub.1.
[0066] According to the exemplary embodiment, the following
advantages will be provided.
(1) The deformation resistance of the outer panel 20 can be
detected as a load acting on the hemming roller 12 in the axial
direction thereof. The deformation resistance is in proportion to
the torque of the servo motor 141. Consequently, by adjusting the
position of the hemming roller 12 in the rotating axis direction
thereof according to the torque by the pushing mechanism 14, the
pressing force exerted on the flange 22 by the hemming roller 12
can be changed according to the deformation resistance of the outer
panel 20.
[0067] Consequently, even if there exists a slight variation in
material or height of flanges 22 of outer panels 20 lot by lot,
shapes of hemmed flanges 22 of outer panels 20 can be made constant
by changing the hemming conditions as required.
[0068] In addition, since the distance between the bending point A
of the flange 22 and the pressing point of the hemming roller 12 is
adjusted by controlling the pushing mechanism 14, the buckling of
the outer panel 20 can be prevented.
[0069] When the torque detected by the load detection sensor 142 is
larger than the torque reference value, the hemming roller 12 is
positioned in the direction in which the flange 22 is bent largely.
Namely, when the deformation resistance of the outer panel 20 is
large, the pressing force exerted on the flange 22 by the hemming
roller 12 is increased by adjusting the position of the hemming
roller 12 with respect to the rotating axis direction thereof.
Consequently, shapes of hemmed flanges 22 of outer panels 20 after
hemming can be made constant in an ensured fashion.
[0070] The invention is not limited to the exemplary embodiment
that has been described heretofore, and modifications and
improvements which can attain the object of the invention without
departing the spirit and scope of the invention are to be included
in the invention.
[0071] For example, in the exemplary embodiment, while the riser
plane 321 is provided on the die 32 so as to determine the abutment
position of the hemming roller 12 with the flange 22, the invention
is not limited thereto. For example, the abutment position of the
hemming roller 12 with the flange 22 may be determined by
controlling the position of the hemming roller 12 with respect to a
direction which is perpendicular to the rotating axis direction
thereof or providing a stepped portion on the distal end face 121
of the hemming roller 12.
[0072] In addition, in the exemplary embodiment, while when the
difference calculated by the differential load calculation unit 56
is positive, the position command value calculation unit 57
increases the position command value at all times in proportion to
a magnitude of the difference, the invention is not limited
thereto. For example, even if the difference calculated is
positive, when the magnitude of the difference exceeds a given
range, it is determined that the hemming operation should not be
allowed, and driving the roller hemming apparatus 10 may be stopped
to cease the hemming operation while informing the occurrence of an
error.
* * * * *