JP3595447B2 - Hemming device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hemming device that presses a continuous peripheral portion of a metal plate with a hem blade (metal blade) and sequentially bends the hem blade, and particularly relates to a hemming device in which the hem blade has a shape suitable for high-speed hemming.
[0002]
[Prior art]
As a hemming device applied to the connection between the outer panel and inner panel peripheral parts that constitute the door of a car, etc., a press-type press that presses the outer panel and inner panel peripheral parts from above and below with a pair of vertically arranged dies. And a roller type using a robot arm as disclosed in Japanese Patent Publication No. 5-34101.
[0003]
The latter roller-type hemming device has a configuration in which a roller 5 is rotatably supported by a roller hem unit 4 mounted on the distal end portion of a robot arm 3 as shown in FIG. 7, for example, and FIGS. 8A to 8D. As shown in (1), the continuous bent portion 2 of the work 1 is sequentially bent. 7 shows, for example, an outer panel 1a and an inner panel 1b of an automobile door. The peripheral edge of the outer panel 1a positioned on the lower die 6 is bent upward at a substantially right angle in advance, and the peripheral edge of the inner panel 1b is placed along the peripheral edge. The bent peripheral portion of the outer panel 1a is the bent portion 2 to be hemmed by the roller 5.
[0004]
First, as shown in FIG. 8A, the roller 5 is pressed against the upper end of a part of the bent portion 2 by the robot arm 3 and bent by the roller 5 as shown in FIG. The portion 2 is pre-hemmed (preliminary bending) to an angle of approximately 45 °, and the roller 5 is rotated laterally along the bent portion 2 so that the bent portion 2 is sequentially rotated by approximately 45 °. By bending at an angle of ゜, the entire length of the bent portion 2 is pre-hemmed. Next, as shown in FIG. 8 (C), the roller 5 is pressed from directly above onto a part of the pre-hemmed bent portion 2 so as to form the bent portion 2 as shown in FIG. 8 (D). 2 is bent to the upper surface of the peripheral edge of the inner panel (final bending). The roller 5 is rotated in the lateral direction along the bent portion 2 as it is, and the entire length of the bent portion 2 is subjected to the main hemming.
[0005]
[Problems to be solved by the invention]
The press type hemming apparatus using a pair of upper and lower dies requires a large-sized facility because a pair of upper and lower dies corresponding to the shape of the work are used. In addition, since it is necessary to prepare many types of dies for each type of work, there are problems that the manufacturing cost increases, and that it takes a lot of time to change the dies and productivity is deteriorated. Therefore, it is not suitable for high-mix low-volume production.
[0006]
In the case of a roller-type hemming device, the roller is pressed directly against the bent portion of the work, which is a metal plate, and is bent. This requires a robot capable of withstanding a high load, and as a result, the equipment cost of the entire hemming device becomes excessive.
[0007]
Furthermore, since the robot arm may be bent by the high pressure applied to the rollers during the hemming process, the teaching performed before the hemming process requires high-precision teaching in consideration of the bending amount of the robot arm. It is difficult to perform precision teaching with high reliability. In the actual teaching, the teaching is corrected as many as ten or more times using the actual work after the first teaching. However, this requires a large amount of adjustment man-hour and time, and it is difficult to improve the work efficiency.
[0008]
In addition, the shape of the continuous bent portion of the workpiece in the length direction is various such as a substantially straight line or a curved line, and the substantially straight portion and the curved portion of the bent portion are added by the way of contact of the roller or the roller. Since the applied pressures are different, if the entire length of the bent portion is hemmed with one type of roller, it becomes difficult to perform particularly favorable processing of the curved portion. Therefore, the curved portion of the bent portion is roughly hemmed with a roller, and then manually corrected by hitting with a hammer later. Automation becomes difficult.
[0009]
In addition, the presence of the curved portion makes it difficult to bend the continuous bent portion of the work with a uniform pressing force using a roller over the entire length. The thickness of the portion (corresponding to the thickness d in FIG. 8D) may be non-uniform, which may result in quality deterioration.
[0010]
In addition, multiple types of rollers with different diameters can be exchanged and mounted on the robot arm, and the heaviness of the bent part of the work is processed with a large diameter roller and the curved part with a small diameter roller. However, there is a problem that the equipment cost is increased due to a plurality of types of rollers and the workability is reduced due to roller replacement.
[0011]
An object of the present invention is to provide a hemming device capable of hemming a workpiece with high quality and with high work efficiency without increasing the equipment cost.
[0012]
[Means for Solving the Problems]
As a hemming device for achieving the above object, the present applicant has previously filed an application for the following hemming device (Japanese Patent Application No. 9-57659). This prior-art hemming device uses a hem blade attached to a robot arm via a vibration source to bend a continuous bent part of a workpiece by applying vibration to the bent part in the vibration direction while applying vibration to the bent part. The hem blade is laterally moved along the bent portion to continuously bend the bent portion. This hemming device does not require a special mold, so that the type of work can be changed easily compared to the press method. In addition, the hemming of the bent part of the work using the vibration energy of the hem blade Since the processing is performed, the thickness of the bent portion can be easily made uniform as compared with the roller type, and the effect that a low-load, low-load-bearing one can be applied to the robot arm has been demonstrated.
[0013]
The present invention improves the hemming blade without impairing the effects of the above-mentioned prior-art hemming device, and facilitates high-speed hemming. That is, according to the present invention, a hem blade is attached to a robot arm via a vibration source, and a continuous bent portion of the workpiece is pressed and bent by a hem blade driven by the vibration source, and the hem blade is folded as it is. In a hemming device that continuously bends a bent part by laterally moving it along the bent part, the processing surface that directly presses the bent part of the work of the hem blade is convex in the hem blade lateral movement direction. This processing surface is a curved surface, and the processing surface is a predetermined wide area in the hem blade moving direction, a central curved surface close to a flat surface that maximizes a radius of curvature, and a continuous surface before and after in the hem blade moving direction from the central curved surface. A predetermined narrow region that extends in a horizontal direction, and has end curved surfaces at both ends having a minimum radius of curvature smaller than the radius of curvature of the central curved surface.
[0014]
The central curved surface of the processing surface of the hem blade is a substantially flat curved surface having a width of 30 mm and a radius of curvature of 200 mm.
[0015]
Here, the central curved surface of the processing surface of the convex curved surface of the hem blade is widened in the hem blade moving direction, and the radius of curvature is maximized, so that the central curved surface becomes a substantially flat curved surface. Since the work is bent at a time in a wide area, the feed pitch of the hem blade that moves on the work by vibrating can be increased, the feed speed can be increased, and the speed of hemming can be increased. Particularly, in the case of a hem blade of a hemming device for an automobile door, an approximately flat curved surface having a width of about 30 mm and a radius of curvature of about 200 mm is appropriate for the central curved surface of the processed surface.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. Note that the same or corresponding portions are denoted by the same reference numerals throughout all the drawings including FIGS. 7 and 8 to avoid duplication of description.
[0017]
1A and 1B are a front view and a side view of a hem blade 8 which is a feature of the present invention. FIGS. 2A and 2B show a specific example of a hemming device using the hem blade 8. Shown. The hemming device of FIG. 2 is the same as the hemming device of the prior application except for the hem blade 8, and before the detailed description of the hem blade 8, the hemming device of FIG.
[0018]
In the hemming device shown in FIG. 2, a hem blade unit 7 and a vibration source 9 for vibrating the hem blade unit 7 are attached to the tip of the robot arm 3. Assuming that the length direction of the bent portion 2 of the workpiece 1 installed at the fixed position is the X-axis direction, and the vibration direction of the hem blade unit 7, which is the vertical direction perpendicular to the X-axis direction, is the Z-axis direction, A hem blade unit 7 and a vibration source 9 are installed at the tip of the arm 3 via a Z-axis free mechanism 11 and an X-axis free mechanism 12.
[0019]
The Z-axis free mechanism 11 includes a Z-axis slide 13 that can be displaced in the Z-axis direction, and a Z-axis elastic member 14 that elastically holds the Z-axis slide 13 at the tip of the robot arm 3 so as to be displaceable in the Z-axis direction. The Z-axis elastic member 14 is, for example, a pair of urethane springs installed above and below the Z-axis slide 13, and holds the Z-axis slide 13 from above and below at the midpoint position in FIG. 2A with an elastic load of about 100 kg, for example. .
[0020]
The hem blade unit 7 and the vibration source 9 are installed on the front side of the Z-axis slide 13 via the X-axis free mechanism 12. The X-axis free mechanism 12 includes a rail 15 installed on the front surface of the Z-axis slide 13 in the X-axis direction, an X-axis slide 16 supported on the rail 15 so as to be displaceable in the X-axis direction, and an X-axis slide 16. It has an X-axis elastic member 17 that keeps elastic pressure in the axial direction. The X-axis elastic member 17 is, for example, a pair of compression springs that resiliently press the opposite ends of the X-axis slide 16, and is installed between both end surfaces of the X-axis slide 16 and brackets 18 projecting from both front ends of the Z-axis slide 13. . The X-axis elastic member 17 holds the X-axis slide 16 at the midpoint of FIG. 2B with an elastic load of, for example, about 30 kg from the left and right.
[0021]
The hem blade unit 7 is installed at the lower part of the front of the X-axis slide 16, and the vibration source 9 is installed at the upper part of the front. The hem blade unit 7 supports the tool 8 ′ extending in the Z-axis direction, the hem blade 8 fixed to the tip of the tool 8 ′, and the tool 8 ′ at the lower front part of the X-axis slide 16 so as to be able to vibrate in the X-axis direction. The guide 21 is provided. The base end of the tool 21 and the vibration source 9 are connected via a stroke adjustment bracket 22. The vibration source 9 applies a vibration of a specific frequency and amplitude to the tool 8 'in the Z-axis direction. Although an air cylinder is shown in FIG. 2, an electric motor, a hydraulic motor, or the like may be used. The weight 23 is attached to the hem blade unit 7 and the weight 24 is detachably attached to the vibration source 9 for reasons to be described later.
[0022]
The hemming of the workpiece 1 by the hemming device of FIG. 2 is performed in the manner shown in FIGS. 3A to 3H while maintaining the state in which the hem blade 8 is vibrated in the Z-axis direction by the vibration source 9. When the work 1 is an outer panel and an inner panel of an automobile door, the hem blade 8 is vibrated at a frequency of about 10 Hz and an amplitude of several mm to be pressed against the bent portion 2 of the work 1, and the hammer caused by the vibration energy of the hem blade 8. The bent portion 2 is sequentially bent by the ring effect and the pressing force.
[0023]
For example, when the vibration source 9 is an air cylinder, this air cylinder is on / off controlled by a solenoid valve at a frequency of about 10 Hz, and the amplitude is set to, for example, about 11 mm by the stroke adjustment bracket 22, as shown in FIG. The hem blade 8 is obliquely pressed against a part of the upper end of the bent portion 2 bent in the Z-axis direction of the work 1 and is moved forward (lateral movement) as shown in FIG. Let it. Then, the bent portion 2 is pushed and bent while being vibrated by the vibrating hem blade 8, and as shown in FIG. 3 (C), when the hem blade 8 advances by a fixed amount and preheming is performed, The blade 8 moves laterally in the X-axis direction, which is the length direction of the bent portion 2, while vibrating, and prehem processing is performed over the entire length of the bent portion 2.
[0024]
When the hem blade 8 makes a full turn around the bent portion 2 and completes the preheming process of the entire length of the bent portion 2, as shown in FIG. 3E, and then moves directly above the bent portion 2 as shown in FIG. 3 (E), and descends while vibrating as it is to press the pre-hem processed bent portion 2 to perform bookbinding. Hemming is started. The main hemming is performed in the process shown in FIGS. 3F and 3G. When the main hemming of a part of the bent portion 2 is completed, the hem blade 8 oscillates in the X-axis direction while vibrating. The main hemming process is performed by moving the entire length of the bent portion 2. When the hem processing is completed, the hem blade 8 separates from the bent part 2 as shown in FIG.
[0025]
The hemming process of the bent portion 2 by the vibrating hem blade 8 as described above is performed reliably and with low energy by the hammering effect in which the vibrating hem blade 8 bends while bending the bent portion 2. Be done. Therefore, it is not necessary to press the hem blade 8 on the bent portion 2 with a high pressing force by the robot arm 3, and it is possible to reduce the equipment cost by applying a small load-bearing robot to the robot arm 3. . Further, since the hem blade 8 may be pressed by the robot arm 3 against the bent portion 2 with a small pressing force, the bending of the robot arm 3 at the time of the hemming process hardly occurs, and the teaching performed before the hemming process is performed by the robot. This can be performed easily and quickly without considering the bending of the arm 3. In fact, even if teaching is performed only at the key points of the bent part, high-precision teaching becomes possible.
[0026]
When the vibrating hem blade 8 is pressed against the bent portion 2 of the work 1, the vibration energy is transmitted to the robot arm 3 via the X-axis free mechanism 12 and the Z-axis free mechanism 11. Most of the vibration energy is absorbed by the elastic member 14 of the Z-axis free mechanism 11, and the vibration of the robot arm 3 is suppressed. Furthermore, the vibration of the hem blade 8 is accompanied by the vibration of the hem blade unit 7 and the vibration source 9, and the vibration of the respective components may cause the robot arm 3 to resonate and suffer mechanical damage. By adjusting the weight of the weight 23 of the hem blade unit 7 and the weight 24 of the vibration source 9, the weight can be suppressed without any problem. For example, when the hem blade 8 is vibrated at a frequency of 10 Hz and the amplitude is 2 mm, the weight 23 of the hem blade unit 7 is adjusted to 15 kg and the weight 24 of the vibration source 9 is adjusted to 45 kg. The robot arm 3 hardly resonates due to the vibration of the hem blade 8. By executing such a resonance suppression measure by adjusting the weight balance, it becomes possible to set an appropriate vibration frequency of the hem blade 8 in a wider band.
[0027]
Next, an example of the hemming operation of the bent portion 2 in the X-axis direction by the hem blade 8 will be described with reference to FIG. After bending the hem blade 8 vibrated by the robot arm 3 to a regular angle while pressing the hem blade 8 against a part of the bent portion 2, the hem blade 8 is laterally moved in the X-axis direction along the bent portion 2. When the bent portion 2 is sequentially bent to a regular angle, a load is applied to the hem blade 8 in the anti-X-axis direction due to contact resistance with the bent portion 2. Here, the hem blade 8 is attached to the robot arm 3 via the X-axis free mechanism 12 so as to be displaceable in the X-axis direction and the anti-X-axis direction. The blade 8 can be displaced in the anti-X-axis direction, and by utilizing this, the hem blade 8 is laterally moved with respect to the robot arm 3 as shown in FIGS.
[0028]
First, as shown in FIG. 4A, when the hem blade 8 and the centers S ₁ and S ₂ of the robot arm 3 coincide with each other, the hem blade 8 is laterally moved in the X-axis direction by the robot arm 3 to be bent. The part 2 is hemmed in order. At the time of this processing, the lateral movement of the hem blade 8 in the X-axis direction is gradually delayed from the robot arm 3 by a load applied to the hem blade 8 in the anti-X-axis direction, and as shown in FIG. When the center S ₂ of heme blade 8 from S ₁ is delayed by a predetermined distance L, which is detected by an optical sensor (not shown) delaying the horizontal moving speed of the robot arm 3, for example, is stopped. Then, only the hem blade 8 continues the lateral movement in the X-axis direction due to the elastic force (about 30 kg) in the X-axis direction by the elastic member 17 of the X-axis free mechanism 12, and as shown in FIG. When the center S ₂ approaches the center S ₁ of the stopped robot arm 3 and the two centers S ₁ and S ₂ coincide as shown in FIG. 4D, the robot arm 3 is again laterally moved at the original speed. Let it. While the robot arm 3 stops and the hem blade 8 catches up, the hem blade 8 bends the bent portion 2 sequentially in the X-axis direction while vibrating. The above-described intermittent lateral movement and stop of the robot arm 3 are repeated, and hemming is performed by the hem blade 8 over the entire length of the bent portion 2.
[0029]
In the case of the hemming process performed by repeating the operation of delaying and catching up the hem blade 8 with respect to the robot arm 3 that moves laterally as shown in FIG. 4, the portion directly processed by the hem blade 8 of the bent portion 2. It is possible to perform the processing continuously while checking the processing accuracy of each place one by one, and it becomes easy to make the processing accuracy uniform and high accuracy. In fact, when the bent part 2 is processed in the manner shown in FIG. 4, uniform control of the vibration energy applied to each part of the bent part 2 for processing becomes easy, and the total length of the bent part 2 is reduced. Finally, it becomes easy to make the thickness (corresponding to the thickness d in FIG. 4D) over the entire length when this hem processing is performed.
[0030]
Next, the features of the shape of the hem blade 8 and how to use it will be described with reference to FIGS. In the hem blade 8 shown in FIG. 1, the processing surface N to press and bend the bent portion 2 of the work 1 is a convex curved surface, and the central curved surface Na of the processed surface N has a predetermined maximum radius of curvature Ra. The end curved surface Nb at both ends continuously extending to the front and rear ends of the central curved surface Na of the processed surface N is finished to a narrow curved surface having a minimum radius of curvature Rb. The maximum radius of curvature Ra is set to be much larger than the minimum radius of curvature Rb, and the central curved surface Na is a curved surface close to a flat surface. Specifically, the central curved surface Na is set to a substantially flat wide curved surface having a width W of approximately 30 mm and a radius of curvature Ra of approximately 200 mm, and an end curved surface Nb having a radius of curvature of 15 mm from both ends of the central curved surface Na is smooth. Is set to extend. The curved end portion Nb having a radius of curvature of 15 mm is suitable for gradually bending the bent portion 2 of the work 1 and particularly for hemming a curved portion 2b of the bent portion 2 shown in FIG. The curvature is set as follows.
[0031]
When the substantially straight portion 2a of the bent portion 2 shown in FIG. 5A is machined, the hem blade 8 is applied substantially perpendicularly to the substantially straight portion 2a as shown in FIG. The bent portion 2 is gradually bent at the end curved surface Nb, and the bent portion 2 is pressed at a central curved surface Na to a predetermined angle to be bent. Further, when the curved portion 2b of the bent portion 2 is hemmed with the wide central curved surface Na of the processing surface N, the central curved surface Na having a large radius of curvature may partially protrude from the curved portion 2b. In this case, when the hem blade 8 moves to the curved portion 2b, the hem blade 8 is inclined in the X-axis direction as shown in FIG. The hemming of the curved portion 2b is mainly performed at the end curved surface Nb of N having a small radius of curvature.
[0032]
The inclination of the hem blade 8 as shown in FIG. 5C is automatically performed by using the reaction force (1) in the counter X-axis direction which the hem blade 8 receives from the work 1. That is, when the hem blade 8 reaches the curved portion 2b, the reaction force (1) acting on the hem blade 8 from the work 1 increases more than before, but at this time, the hem blade 8 Since the hem blade 8 is supported so as to be elastically displaceable in the axial direction, the hem blade 8 is automatically inclined against the elastic force of the X-axis elastic member 17. By inclining the hem blade 8 in accordance with the curvature of the curved portion 2b in this manner, the end curved surface Nb of the processing surface N appropriately abuts on the curved portion 2b, and the proper hemming of the curved portion 2b can be performed. Become. As described above, by the selective use of the processing surfaces N having different curvature radii of the hem blade 8, both the substantially straight portion 2a and the curved portion 2b of the bent portion 2 of the work 1 are the same hem blade 8. Good hemming can be performed. Therefore, the labor for preparing and replacing a variety of hem blades can be omitted, the work efficiency of hemming can be easily improved, and the number of components including the hem blade can be reduced, thereby reducing the equipment cost.
[0033]
By making the central curved surface Na of the processing surface N of the hem blade 8 a wide curved surface close to a flat surface, the center curved surface Na presses the bent portion 2 to be bent by vibration energy ( As a result, the area to be bent 2 is bent at high speed and with high quality.
[0034]
The hem blade 8 in FIG. 6 vibrates at a predetermined amplitude in the Z-axis direction, advances at a predetermined pitch P in the X-axis direction, and sequentially bends the bent portion 2. Since the wide central curved surface Na of the hem blade 8 strikes and bends the bent portion 2 at a wide striking width W at a time, the feed pitch p of the hem blade 8 is set to the width W of the central curved surface Na. Even if it is set to be proportionally large and the bent portion 2 is struck and bent at a wide interval, it can be bent with a uniform thickness. Accordingly, the feed pitch p of the hem blade 8 can be set large in proportion to the width W of the central curved surface Na, and the feed speed of the hem blade 8 can be increased accordingly.
[0035]
In the hemming process using the hem blade 8 of the present invention shown in FIG. 6 described above, it is easy to increase the feed speed of the hem blade 8 in the X-axis direction. Is possible. Actually, the robot moving speed at the time of hemming a car door can be increased to about 5 to 10 times that of existing equipment.
[0036]
The radius of curvature Ra of the central curved surface Na of the processing surface N of the hem blade 8 of the present invention is preferably about 200 mm. That is, although it is conceivable to make the central curved surface Na a flat surface with an infinite radius of curvature, even if the surface of the bent portion 2 of the work 1 such as an automobile door is a flat surface, a slight uneven curved surface is formed. Usually, such a concave / convex curved surface is struck by the flattened surface of the central curved surface Na so that the concave curved surface of the concave / convex curved surface is not struck. It may not be possible to bend at a uniform thickness. Therefore, the radius of curvature Ra of the central curved surface Na is appropriately about 200 mm corresponding to the slightly uneven curved surface of the surface of the bent portion 2.
[0037]
【The invention's effect】
According to the present invention, the processing surface of the hem blade is composed of a wide central curved surface having a large radius of curvature and an end curved surface having a small width and a small radius of curvature. Since the bending is performed while applying vibration on the curved surface, the area that can be bent at once by the hem blade of the part to be bent of the work is widened, and therefore the forward pitch of the vibrating hem blade is increased and the forward speed is increased However, high-quality preheming or main hemming of the bent portion can be easily performed, and the hemming speed can be increased.
[Brief description of the drawings]
FIG. 1A is a front view showing an embodiment of a hem blade used in a hemming device according to the present invention, and FIG. 1B is a side view of the hem blade.
2A is a side view of a hemming device using the hem blade of FIG. 1, and FIG. 2B is a front view thereof.
3 (A) to 3 (H) are cross-sectional views in each processing step showing a hemming processing operation by the hemming device of FIG. 2;
4 (A) to 4 (D) are front views in respective processing steps showing an outline of a hemming processing operation when the hemming blade is laterally moved by the hemming device of FIG. 2;
FIG. 5A is a plan view of a bent portion of a work, and FIGS. 5B and 5C are front views showing states of the hem blade at the time of hemming at two locations of FIG. .
FIG. 6 is a front view for explaining speeding up at the time of hemming by the hem blade according to the present invention.
FIG. 7 is a side view of a conventional roller-type hemming device.
8 (A) to 8 (D) are cross-sectional views in each processing step showing a hemming operation by the hemming device of FIG. 7;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Work 2 Bending part 3 Robot arm 8 Hem blade N Working surface Na Central curved surface Nb End curved surface

Claims (1)

A hem blade is attached to the robot arm via the vibration source, and the continuous bent part of the workpiece is pressed and bent by the hem blade driven by the vibration source, and the hem blade is moved along the bent part as it is. In a hemming device that continuously moves and bends a part to be bent,
The processing surface for directly pressing the bent portion of the work of the hem blade is a convex curved surface in the hem blade lateral movement direction, and this processing surface has a predetermined radius in the hem blade movement direction, and has a radius of curvature. A central curved surface of a curved surface close to a flat surface to be maximized, and a predetermined narrow region continuously extending from the central curved surface back and forth in the hem blade moving direction, and a minimum curvature smaller than a radius of curvature of the central curved surface. A hemming device comprising: an end curved surface at both ends of a radius.

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