Patent Publication Number: US-10758958-B2

Title: Roller hemming processing method and roller hemming processing device

Description:
INCORPORATION BY REFERENCE 
     The disclosure of Japanese Patent Application No. 2017-200225 filed on Oct. 16, 2017 including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The disclosure relates to a roller hemming processing method and a roller hemming processing device for use in this method. 
     2. Description of Related Art 
     Hemming processing is carried out by folding back an edge portion of a panel by 180°, with a view to increasing the strength of the edge portion of the panel and ensuring safety in the case, for example, where someone&#39;s hand touches the edge portion of the panel. This hemming processing encompasses press hemming processing for bending the edge portion of the panel by means of press processing through the use of a hemming die (a hemming blade) or the like, and roller hemming processing for bending the edge portion of the panel by means of a roller. 
     This hemming processing is also used to perform so-called hemming coupling. In hemming coupling, for example, an outer panel having a flange (a hemming flange) provided at an edge portion thereof and an inner panel are stacked on each other, the hemming flange is folded back by 90°, and an edge portion of the inner panel is sandwiched between the outer panel and the folded-back hemming flange to couple the outer panel and the inner panel to each other. 
     It should be noted herein that the hemming flange of the outer panel may simply be folded back by 90° to be brought into close contact with the inner panel in the case where the edge portion of the inner panel is flat. It is therefore easy to perform hemming coupling between the outer panel and the inner panel. On the contrary, in the case, for example, where a flange (an inner flange) is provided on the inner panel, a space enveloping the inner flange must also be formed in addition to the need to bring a leading end portion of the folded-back hemming flange into close contact with the inner panel. Accordingly, it may not be easy to perform hemming coupling between the outer panel and the inner panel. 
     Thus, for example, in Japanese Patent Application Publication No. 3-81025 (JP 3-81025 A), there is disclosed a press hemming processing method including a pre-hemming process and a hemming process. In the pre-hemming process, a leading end portion of a hemming flange is folded back toward an inner panel side at a right angle to form a seating flange portion, with an inner flange serving as a core bar, through the use of a pre-hemming die. In the hemming process, the seating flange portion is further folded back toward the inner panel side to bring a leading end portion of the seating flange portion into close contact with the inner panel, and at the same time, to form a terminal portion of a hollow, closed cross-sectional structure, with the inner flange serving as a core bar, through the use of a hemming die. 
     SUMMARY 
     According to the press hemming processing method of the aforementioned Japanese Patent Application Publication No. 3-81025 (JP 3-81025 A), even in the case where the inner flange is provided at the edge portion of the inner panel, hemming coupling can be performed between the outer panel and the inner panel. In general, however, press hemming processing requires a relatively expensive hydraulic press molding device and a processing device as a dedicated facility. In other words, a new processing device must be prepared every time the shapes of the panels to be processed become different. Accordingly, the cost of processing may increase. 
     Thus, it is conceivable to carry out hemming coupling through the use of roller hemming processing even in the case where the inner flange is provided at the edge portion of the inner panel. However, the application of roller hemming processing to this case entails the following possibilities. 
     That is, in roller hemming processing, as shown in  FIG. 10A , it is common to perform hemming coupling between an outer panel  150  and an inner panel  160  by rolling a processing surface  114  parallel to an axis SL of a roller  110  while pressing this processing surface against a hemming flange  151 , which is bent into the shape of a hook (folded back by 180°), after inserting an edge portion of the inner panel  160  into the hemming flange  151  as indicated by a blank arrow. However, when the outer panel and the inner panel assume a certain shape, it may be difficult to insert the edge portion of the inner panel into the hemming flange bent into the shape of a hook. In this case, the hemming flange must be subjected to hemming processing in such a manner as to form a large angle from a state where there is no trigger for bending. As a result, processing may become difficult. 
     Besides, even in the case where a state where an inner flange  161  is inserted in the hemming flange  151  bent into the shape of a hook can be created, when an attempt is made to bend the hemming flange  151  in such a manner as to envelop the inner flange  161  by the processing surface  114  parallel to the axis SL of the roller  110 , the processing surface  114  must be diagonally pressed against the hemming flange  151  folded back toward the inner flange  161  side at a right angle, as shown in  FIG. 10B . That is, the roller  110  must be pressed against the hemming flange  151  folded back toward the inner flange  161  side at a right angle, with the axis SL of the roller  110  inclined with respect to the outer panel  150 . Accordingly, there is also a possibility of interference between a receiving pedestal  125  for the panels and the roller  110 . 
     Furthermore, as shown in  FIG. 10C , when an attempt is made to process the hemming flange  151  folded back toward the inner flange  161  side at a right angle just once through the pressing and rolling of the processing surface, a leading end of the hemming flange  151  and the inner panel  160  interfere with each other, so it becomes difficult to mold a hem portion as a leading end portion that is in close contact with the inner panel  160 . 
     The disclosure provides an art for realizing hemming coupling between one panel and the other panel by bending a flange provided at an edge portion of one panel in such a manner as to envelop a flange provided at an edge portion of the other panel even from a state where there is no trigger for bending, while reducing the cost of processing. 
     In a roller hemming processing method according to the disclosure and a roller hemming processing device according to the disclosure, a plurality of processing surfaces that are different from one another in angle of inclination and direction of inclination with respect to an axis of a roller are selectively used in accordance with the stage of processing. 
     In a roller hemming processing method according to one aspect of the disclosure, a first flange provided at an edge portion of a first panel is bent in such a manner as to envelop a second flange provided at an edge portion of a second panel stacked on the first panel and having a shorter length than the first flange, by rolling processing surfaces of a roller portion pressed against the first flange along the first flange, through the use of a roller that is constituted of the roller portion and a shaft portion parallel to an axis of the roller. 
     This roller hemming processing method has first to fourth processes. As the first process, a roller hemming processing device that has a plurality of processing surfaces including at least a first processing surface parallel to the axis of the roller, a second processing surface that is inclined from the first processing surface toward a side of the shaft portion at a predetermined angle with respect to the axis of the roller, and two or more tapered processing surfaces that are inclined toward a leading end side of the roller at different angles with respect to the axis of the roller respectively, and that rolls the respective processing surfaces while pressing the respective processing surfaces against the first flange in such a posture that the axis of the roller is parallel to the first panel is prepared, and the second panel is fixed to the first panel stacked on the second panel such that the first flange and the second flange overlap with each other. As the second process, a plurality of selected processing surfaces other than the second processing surface are pressed against a region of the first flange that protrudes from the second flange in a stepwise manner such that an angle of inclination with respect to the axis of the roller decreases, and a pre-processed portion that is obtained by bending this region toward a side of the second flange in such a manner as to form a right angle with the second flange is molded. As the third process, the second processing surface is pressed against the pre-processed portion, and the pre-processed portion is inclined toward a side of the second panel within such a range as not to come into contact with the second panel. As the fourth process, the first processing surface and the second processing surface are simultaneously pressed against the inclined pre-processed portion, and the inclined pre-processed portion is molded into an inclined wall portion that is inclined at the predetermined angle and that has a leading end abutting on the second panel, and a hem portion that extends from a leading end portion of the inclined wall portion and that is in close contact with the second panel. 
     Incidentally, in the disclosure, “the first (or the second) flange provided at the edge portion of the first (or the second) panel” means a flange that extends from the edge portion of the panel perpendicularly to the panel. 
     Besides, as for “the plurality of the processing surfaces”, only the first processing surface and the second processing surface may be required to correspond to the axis of the roller (formed at a common roller portion), whereas the other processing surfaces may correspond to the axis of the roller that is common to the first processing surface and the second processing surface (formed on the common roller) or correspond to axes of different rollers (formed on different rollers). 
     Furthermore, as long as “the plurality of the processing surfaces” include at least the first processing surface, the second processing surface and the two or more tapered processing surfaces, they may further include, for example, one or more processing surfaces parallel to the axis of the roller, such as the first processing surface. 
     Based on these premises, according to the disclosure, the pre-processed portion is molded by using a plurality of the selected processing surfaces other than the second processing surface in a stepwise manner such that the angle of inclination with respect to the axis of the roller decreases. More specifically, the tapered processing surface (provisionally referred to as a first tapered processing surface) that is inclined toward the leading end side of the roller at, for example, 60° with respect to the axis of the roller, the tapered processing surface (provisionally referred to as a second tapered processing surface) that is inclined toward the leading end side of the roller at, for example, 30° with respect to the axis of the roller, and the processing surface (provisionally referred to as a flat processing surface) that is parallel to the axis of the roller are selected from the processing surfaces other than the second processing surface. Then, when the first tapered processing surface that is inclined at the larger angle with respect to the axis of the roller is rolled while being pressed against the region of the first flange that protrudes from the second flange in such a posture that the axis of the roller is parallel to the first panel, this region is inclined toward the side of the second flange by 30° while the second flange overlapping with the first flange serves as a core bar. 
     Subsequently, when the second tapered processing surface is rolled while being pressed against the region of the first flange inclined by 30° in such a posture that the axis of the roller is parallel to the first panel, this region is inclined toward the side of the second flange by 60° with the second flange serving as a core bar. Furthermore, when the flat processing surface parallel to the axis of the roller (inclined at an angle of 0°) is rolled while being pressed against the region of the first flange inclined by 60° in such a posture that the axis of the roller is parallel to the first panel, the pre-processed portion bent toward the side of the second flange in such a manner as to form a right angle with the second flange is molded with the second flange serving as a core bar. Incidentally, the flat processing surface may be the first processing surface. 
     As described hitherto, according to the disclosure, the first flange provided at the edge portion of the first panel can be bent into the shape of a hook from a state where there is no trigger for bending, even when no pre-hemming die as in the case of press hemming processing is used. Moreover, the pre-processed portion is molded through the use of two or more tapered processing surfaces, in other words, in three or more stages. Thus, a strain can be restrained from being generated when the bending amount in each bending cycle is large. 
     By the way, when the second processing surface is pressed at once against the pre-processed portion thus molded by a large pressing amount, the leading end of the inclined pre-processed portion comes into contact with the second panel in addition to the generation of a strain. As a result, it may become difficult to mold the hem portion. 
     Thus, in the disclosure, the pre-processed portion is inclined toward the side of the second panel within such a range as not to come into contact with the second panel, by pressing the second processing surface against the pre-processed portion. When the second processing surface is rolled while being pressed against the pre-processed portion, the pre-processed portion is inclined such that the leading end thereof approaches the second panel, with the second flange serving as a core bar. 
     Subsequently, when the first processing surface and the second processing surface are rolled while being simultaneously pressed against the inclined pre-processed portion, the inclined wall portion that is inclined at the predetermined angle and that has the leading end in contact with the second panel is molded by the second processing surface, with the second flange serving as a core bar. At the same time, the leading end portion of the inclined pre-processed portion is sandwiched between the second panel and the first processing surface and is molded into the hem portion that is in close contact with the second panel. 
     As described above, according to the disclosure, hemming coupling can be performed between the first panel and the second panel by bending the first flange erected on the first panel in such a manner as to envelop the second flange erected on the second panel, even from the state where there is no trigger for bending. 
     Moreover, there is no need for any relatively expensive hydraulic press molding device, and even panels of different shapes can be subjected to hemming processing through the use of a common roller, simply by replacing a jig or the like for fixing the panels. Therefore, the cost of processing can be made lower than in the case of press hemming processing that requires a processing device as a dedicated facility. 
     Furthermore, the inclined wall portion can be molded while maintaining such a posture that the axis of the roller is parallel to the first panel, through the use of the second processing surface that narrows toward the side of the shaft portion. Therefore, the receiving pedestal for the panels and the roller can be restrained from interfering with each other. 
     Besides, in the aforementioned roller hemming processing method, a first pressing amount by which the second processing surface is pressed against the pre-processed portion in the third process may be smaller than a second pressing amount by which the first processing surface and the second processing surface are pressed against the inclined pre-processed portion in the fourth process. 
     According to this configuration, a strain can be restrained from being generated in the case where the bending amount in each bending cycle is large, and the leading end of the inclined pre-processed portion can be easily restrained from coming into contact with the second panel, by setting the first pressing amount as a relatively small pressing amount. Furthermore, the inclined wall portion inclined at the predetermined angle and the hem portion that is in close contact with the second panel can be easily molded with a simple configuration where the first processing surface and the second processing surface are simultaneously pressed by the second pressing amount that is larger than the first pressing amount. 
     Besides, in the aforementioned roller hemming processing method, the first panel may be an outer panel of a vehicular sun roof in which an opening portion is formed, the second panel may be an inner panel of the vehicular sun roof, and the first flange and the second flange may be erected at edge portions that define the opening portion, respectively. 
     In the vehicular sun roof, the first flange is often cylindrically erected along the entire circumference of the edge portion that defines the opening portion of the outer panel, and the second flange is often cylindrically erected along the entire circumference of the edge portion that defines the opening portion of the inner panel. Therefore, it is safe to conclude that the outer panel and the inner panel in the vehicular sun roof constitute a typical example in which it is difficult to insert the second flange into the first flange bent into the shape of a hook, because there is no alternative but to insert the cylindrical first flange into the cylindrical second flange from a cylinder axis direction in stacking both the panels on each other. Therefore, the roller hemming processing method according to the disclosure can be used in the case where hemming coupling is performed between the outer and inner panels of the vehicular sun roof. 
     Besides, a roller hemming processing device according to another aspect of the disclosure envelops a second flange provided at an edge portion of a second panel stacked on a first panel and having a shorter length than a first flange erected at an edge portion of the first panel, by rolling processing surfaces of a roller portion pressed against the first flange along the first flange. 
     This roller hemming processing device is equipped with a fixing portion, a roller, and a moving portion. The fixing portion fixes the second panel to the first panel stacked on the second panel such that the first flange and the second flange overlap with each other. The roller is constituted of the roller portion and a shaft portion parallel to an axis of the roller, and has a plurality of processing surfaces including at least a first processing surface parallel to the axis of the roller, a second processing surface that is inclined from the first processing surface toward the side of the shaft portion at a predetermined angle with respect to the axis of the roller, and two or more tapered processing surfaces that are inclined toward a leading end side of the roller at different angles with respect to the axis of the roller respectively, as the processing surfaces. The moving portion selects a processing surface for use from the plurality of the processing surfaces, and moves the roller while pressing the selected processing surface against the first flange in such a posture that the axis of the roller is parallel to the first panel. 
     Then, the moving portion is characterized by being configured to (A) press a plurality of selected processing surfaces other than the second processing surface against a region of the first flange that protrudes from the second flange in a stepwise manner such that an angle of inclination with respect to the axis of the roller decreases, in molding a pre-processed portion that is obtained by bending the region toward the side of the second flange in such a manner as to form a right angle with the second flange, (B) press the second processing surface against the pre-processed portion, in inclining the pre-processed portion toward the side of the second panel within such a range as not to come into contact with the second panel, and (C) simultaneously press the first processing surface and the second processing surface against the inclined pre-processed portion, in molding the inclined pre-processed portion into an inclined wall portion that is inclined at the predetermined angle and that has a leading end abutting on the second panel, and a hem portion that extends from a leading end portion of the inclined wall portion and that is in close contact with the second panel. 
     In the same manner as described above about the roller hemming processing method, this roller hemming processing device makes it possible to perform hemming coupling between the first panel and the second panel by bending the first flange erected on the first panel in such a manner as to envelop the second flange erected on the second panel even from the state where there is no trigger for bending, while reducing the cost of processing. 
     Besides, in the aforementioned roller hemming processing device, a first pressing amount by which the second processing surface is pressed against the pre-processed portion in inclining the pre-processed portion toward the side of the second panel may be set smaller than a second pressing amount by which the first processing surface and the second processing surface are pressed against the inclined pre-processed portion in molding the inclined pre-processed portion into the inclined wall portion and the hem portion. 
     In the same manner as described above about the roller hemming processing method, this configuration makes it possible to restrain a strain from being generated when the bending amount in each bending cycle is large, easily restrain the leading end of the inclined pre-processed portion from coming into contact with the second panel, and easily mold the inclined wall portion and the hem portion with a simple configuration. 
     Besides, in the aforementioned roller hemming processing device, the fixing portion may have a guide portion that binds a region of the first flange that overlaps with the second flange from an opposite side of the second flange, and the moving portion may be configured to move the roller while holding the roller in contact with the guide portion in molding the pre-processed portion. 
     According to this configuration, the region of the first flange that overlaps with the second flange is bound by the guide portion from the opposite side of the second flange. Thus, the first flange can be restrained from swelling toward the opposite side of the second flange in bending the region of the first flange that protrudes from the second flange with a view to molding the pre-processed portion. 
     Besides, in the case where the pre-processed portion is molded, the roller is moved (the processing surface is rolled) while being held in contact with this guide portion. Thus, the first flange can be accurately bent even from the state where there is no trigger for bending. 
     Furthermore, in the aforementioned roller hemming processing device, the roller may have a first roller portion provided on one side of the shaft portion, and a second roller portion provided on the other side of the shaft portion. The first processing surface, the second processing surface, and a third processing surface as one of the tapered processing surfaces, which is inclined from the first processing surface toward a leading end side at a first angle with respect to the axis of the roller, may be formed on the first roller portion, whereas a fourth processing surface parallel to the axis of the roller and a fifth processing surface as one of the tapered processing surfaces, which is inclined from the fourth processing surface toward the leading end side at a second angle with respect to the axis of the roller, may be formed on the second roller portion. The first angle may be set larger than the second angle. 
     According to this configuration, the two roller portions on which the plurality of the processing surfaces required for roller hemming processing are formed are provided on the single roller across the shaft portion. Thus, the highly versatile roller hemming processing device can be performed with a simple configuration in which the roller is inverted in accordance with the selected processing surface. 
     Moreover, the first angle is set larger than the second angle. In other words, the protrusion length of the third processing surface, which is inclined from the first processing surface toward the leading end side, from the first processing surface is relatively short. Thus, the third processing surface that protrudes from the first processing surface can be restrained from interfering with the fixing portion that supports the first panel and the second panel, in molding the inclined wall portion and the hem portion through the use of the first processing surface and the second processing surface. 
     As described above, the roller hemming processing method according to the disclosure and the roller hemming processing device according to the disclosure make it possible to perform hemming coupling between one panel and the other panel by bending a flange provided at an edge portion of one panel in such a manner as to envelop a flange provided at an edge portion of the other panel, even from a state where there is no trigger for bending, while reducing the cost of processing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features, advantages, and technical and industrial significance of exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein: 
         FIG. 1  is a perspective view schematically showing an essential part of a roller hemming processing device according to an embodiment of the disclosure; 
         FIG. 2A  is a cross-sectional view schematically showing an outer panel to be processed and an inner panel to be processed in a state before the start of processing; 
         FIG. 2B  is a cross-sectional view schematically showing the outer panel to be processed and the inner panel to be processed in a state where both the panels are stacked on each other; 
         FIG. 2C  is a cross-sectional view schematically showing the outer panel to be processed and the inner panel to be processed in a state after the completion of processing; 
         FIG. 3  is a perspective view schematically showing the outer panel and the inner panel; 
         FIG. 4  is a cross-sectional view taken along a line IV-IV of  FIG. 1  as viewed in the direction of arrows; 
         FIG. 5  is a view schematically showing a roller; 
         FIG. 6  is a view schematically illustrating a state of the roller at the time of processing; 
         FIG. 7  is a view schematically illustrating the state of the roller at the time of processing; 
         FIG. 8A  is a view schematically illustrating a roller hemming processing method; 
         FIG. 8B  is a view schematically illustrating the roller hemming processing method; 
         FIG. 8C  is a view schematically illustrating the roller hemming processing method; 
         FIG. 8D  is a view schematically illustrating the roller hemming processing method; 
         FIG. 8E  is a view schematically illustrating the roller hemming processing method; 
         FIG. 9  is a view schematically showing a roller according to another embodiment of the disclosure; 
         FIG. 10A  is a view schematically illustrating the possibilities in a roller hemming processing method according to the related art and a roller hemming processing device according to the related art; 
         FIG. 10B  is a view schematically illustrating the possibilities in the roller hemming processing method according to the related art and the roller hemming processing device according to the related art; and 
         FIG. 10C  is a view schematically illustrating the possibilities in the roller hemming processing method according to the related art and the roller hemming processing device according to the related art. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Modes for carrying out the disclosure will be described hereinafter based on the drawings. 
       FIG. 1  is a perspective view schematically showing an essential part of a roller hemming processing device  1  according to an embodiment of the disclosure. Besides, each of  FIGS. 2A, 2B and 2C  is a cross-sectional view schematically showing an outer panel  50  to be processed and an inner panel  60  to be processed.  FIG. 2A  shows a state before the start of processing.  FIG. 2B  shows a state where both the panels are stacked on each other.  FIG. 2C  shows a state after the completion of processing. This roller hemming processing device  1  bends a hemming flange  51  provided at an edge portion of the outer panel  50  in such a manner as to envelop an inner flange  61  provided at an edge portion of the inner panel  60  stacked on the outer panel  50  as shown in  FIG. 2C , by rolling processing surfaces of a roller  10  pressed against the hemming flange  51  along the hemming flange  51 , and thus performs hemming coupling between the outer panel  50  and the inner panel  60 . 
     —Outer Panel and Inner Panel— 
       FIG. 3  is a perspective view schematically showing the outer panel  50  and the inner panel  60 . The outer panel (a first panel)  50  and the inner panel (a second panel)  60  constitute a vehicular sun roof  40  through which an opening portion  45  is formed. 
     Incidentally, for the sake of convenience, the following description will be given on the assumption that “a front side” is defined as a front side of the vehicular sun roof  40  in a vehicle longitudinal direction (a left side in  FIGS. 2A to 2C ), and that “a rear side” is defined as a rear side of the vehicular sun roof  40  in the vehicle longitudinal direction (a right side in  FIGS. 2A to 2C ). 
     Flanges  51 ,  52 ,  53  and  54  that extend downward substantially perpendicularly to the outer panel  50  are provided at edge portions that define an opening portion  55  of the outer panel  50 , respectively, along an entire circumference thereof. These flanges  51 ,  52 ,  53  and  54  are connected at longitudinal end portions thereof to one another, thus assuming the shape of a rectangular cylinder. The hemming flange (a first flange)  51  is provided at an edge portion  50   a  that defines a rear end of the opening portion  55 . The hemming flange  51  is formed longer than the other flanges  52 ,  53  and  54  and extends downward. 
     Flanges  61 ,  62 ,  63  and  64  that extend downward substantially perpendicularly to the inner panel  60  are provided at edge portions that define an opening portion  65  of the inner panel  60 , respectively, along an entire circumference thereof. These flanges  61 ,  62 ,  63  and  64  are connected at longitudinal end portions thereof to one another, thus assuming the shape of a rectangular cylinder. The inner flange (a second flange)  61  is provided at an edge portion  60   a  that defines a rear end of the opening portion  65 , and is formed shorter than the hemming flange  51  (see  FIG. 2B ). Incidentally, a reference symbol  66  in  FIGS. 2A to 2C  denotes a convex portion formed on the inner panel  60  as a design, which is not an indispensable configuration. However, a portion having such an irregular shape may be formed on the inner panel  60 . 
     As described hitherto, the rectangular cylinder-like flanges are erected on both the outer panel  50  and the inner panel  60  respectively. Thus, in stacking the outer panel  50  and the inner panel  60  on each other, the outer panel  50  is stacked on the inner panel  60  in such a manner as to insert the rectangular cylinder-like flanges  51 ,  52 ,  53  and  54  into inner sides of the rectangular cylinder-like flanges  61 ,  62 ,  63  and  64  respectively as shown in  FIG. 2B . Incidentally, hemming coupling is performed only between the hemming flange  51  and the inner flange  61 . The flanges  52 ,  53  and  54  and the flanges  62 ,  63  and  64  are joined to each other respectively through spot welding, after the completion of hemming coupling. 
     —Roller Hemming Processing Device— 
     As shown in  FIG. 1 , the roller hemming processing device  1  is equipped with a fixing jig  20  that fixes the outer panel  50  and the inner panel  60 , which are vertically stacked on each other, to each other, a roller mechanism  3  that has the roller  10  on which a plurality of processing surfaces are formed, and a hemming robot  30  having a robot arm  31  whose leading end has the roller mechanism  3  attached thereto. Incidentally, in  FIG. 1 , for the sake of visibility of the drawing, an upper die  21  and the like included by the fixing jig  20  is omitted. 
       Fixing Jig   
     As shown in  FIG. 1 , the fixing jig (the fixing portion)  20  is provided with a plurality of positioning pins  28  and a plurality of clamp units  29 . The positioning pins  28  are arranged at positions along an outer periphery of the outer panel  50  respectively, and position the outer panel  50  and the inner panel  60  at an appropriate position. Besides, the clamp units  29  integrally pin down the outer panel  50  and the inner panel  60  and fix these panels to the fixing jig  20 , at the edge portions that define front and lateral ends of the opening portion  55  of the outer panel  50 , which are not subjected to hemming processing. Incidentally, the positioning pins  28  and the clamp units  29  are configured such that their positions can be changed, and are also applicable to sun roofs  40  of different types of vehicles. 
       FIG. 4  is a cross-sectional view taken along a line IV-IV of  FIG. 1  as viewed in the direction of arrows. Incidentally, in  FIG. 4 , for the sake of visibility of the drawing, hatching representing a cross-section is omitted. As shown in  FIG. 4 , the fixing jig  20  has a turning mechanism portion  27 , first and second lower dies  25  and  26  that receive (support) the inner panel  60 , and the upper die  21  that integrally pins down the outer panel  50  and the inner panel  60  between these first and second lower dies  25  and  26 . 
     As indicated by a blank arrow in  FIG. 4 , the turning mechanism portion  27  is configured to turn clockwise (or counterclockwise) in  FIG. 4  in accordance with a gradient of the sun roof  40 . The first lower die  25  and the second lower die  26  are removably attached to the turning mechanism portion  27 . Therefore, the fixing jig  20  is also applicable to sun roofs  40  of different types of vehicles by replacing the first lower die  25  and the second lower die  26  and turning the turning mechanism portion  27  in accordance with the shape of the inner panel  60 . Incidentally, the turning mechanism portion  27  is not indispensable. The sun roofs  40  having different gradients may be coped with by preparing the first lower die  25  and the second lower die  26 , which are different in dimension in a height direction from each other. Besides, in  FIG. 4 , the first lower die  25  is arranged in such a manner as to support a lower end of the convex portion  66 . However, the first lower die  25  having the larger height dimension may be used in the case of application to the sun roof  40  with no convex portion  66 . 
     On the other hand, the upper die  21  is arranged at an appropriate position by being placed with respect to a positioning pin (not shown) on the outer panel  50 , which is supported by the first lower die  25  and the second lower die  26  via the inner panel  60 . Arranged at the appropriate position, this upper die  21  has a pad  22  that fixes the outer panel  50  and the inner panel  60  while sandwiching these panels between the pad  22  and the second lower die  26 , a hemming die  23  that presses the edge portion  50   a  of the outer panel  50  from above, and a guide portion  24  that binds a region of the hemming flange  51  that overlaps with the inner flange  61  from the opposite side of the inner flange  61 . The upper die  21  is also applicable to sun roofs  40  of different types of vehicles by being replaced in accordance with the shape of the outer panel  50 . 
     Incidentally, the first lower die  25 , the second lower die  26  and the upper die  21  are configured to be easily replaceable through the robot arm  31  by engaging an engaging bracket (not shown) provided on the roller mechanism  3  with engaged portions (not shown) provided on this first lower die  25 , this second lower die  26  and this upper die  21 . 
       Roller Mechanism   
       FIG. 5  is a view schematically showing the roller  10 . The roller mechanism  3  has the roller  10 , and a roller head  4  that rotatably supports a shaft portion  12  of the roller  10 . The roller  10  has a first roller portion  11  provided on one side of the shaft portion  12 , and a second roller portion  13  provided on the other side of the shaft portion  12 . 
     As shown in  FIG. 5 , a first processing surface  14  as a circular cylinder surface parallel to an axis SL of the roller  10  (hereinafter also referred to simply as the axis SL), a second processing surface  15  as a tapered surface that is inclined at 49° (a predetermined angle) with respect to the axis SL in such a manner as to narrow from the first processing surface  14  toward a base end side (the shaft portion  12  side), and a third processing surface  16  as a tapered surface that is inclined at 60° (a first angle) with respect to the axis SL in such a manner as to narrow from the first processing surface  14  toward a leading end side are formed on the first roller portion  11 . 
     On the other hand, as shown in  FIG. 5 , a fourth processing surface  17  as a circular cylinder surface parallel to the axis SL, and a fifth processing surface  18  as a tapered surface that is inclined at 30° (a second angle) with respect to the axis SL in such a manner as to narrow from the fourth processing surface  17  toward the leading end side are formed on the second roller portion  13 . 
     The third processing surface  16  and the fifth processing surface  18  are formed such that a generatrix of the third processing surface  16  and a generatrix of the fifth processing surface  18  are equal in length to each other. However, an angle of inclination of the third processing surface  16  with respect to the axis SL is set larger than an angle of inclination of the fifth processing surface  18  with respect to the axis SL, so a protrusion length of the third processing surface  16  from the first processing surface  14  is shorter than a protrusion length of the fifth processing surface  18  from the fourth processing surface  17 . 
     Incidentally, in relation to the claims, the third processing surface  16  and the fifth processing surface  18  are equivalent to “the two or more tapered processing surfaces that are inclined toward the leading end side of the roller at different angles with respect to the axis of the roller respectively”. 
       Hemming Robot   
     The hemming robot (the moving portion)  30  is a multi-joint robot and is equipped with the robot arm  31  and a body base  32 . The roller head  4  is connected to a leading end portion  31   a  of the robot arm  31  via a spring  35  (see  FIGS. 6 and 7 ). Therefore, the roller head  4  is always urged toward the robot arm  31  side. The body base  32  is fixed to a robot pedestal  33  in a swingable manner. The leading end portion  31   a  of the robot arm  31  is rotatably configured and can freely change the direction of the roller  10  supported by the roller head  4 . 
     This hemming robot  30  is taught to select a processing surface for use from the first processing surface  14 , the second processing surface  15 , the third processing surface  16 , the fourth processing surface  17  and the fifth processing surface  18  in accordance with the processing stage, and move the roller  10  along the edge portion  50   a  while pressing the selected processing surface against the hemming flange  51  from below in such a posture that the axis SL of the roller  10  is substantially parallel to the outer panel  50 . 
     Each of  FIGS. 6 and 7  is a view schematically illustrating a state of the roller  10  at the timing of processing. In concrete terms, as indicated by a blackened arrow in  FIG. 6 , the hemming robot  30  is taught to move the roller  10  such that the selected processing surface is located directly below a location to be processed, and then draw up the robot arm  31  in such a posture that the axis SL of the roller  10  is substantially parallel to the outer panel  50 . When the robot arm  31  is drawn up, the roller head  4  is pulled upward due to an urging force of the spring  35 , and the selected processing surface is pressed against the location to be processed. Thus, with the aid of the urging force of the spring  35 , even if an actual locus deviates from a teaching locus due to deflection of the robot arm  31 , the backlash of respective joints of the hemming robot  30  or the like, the selected processing surface can be rolled along the teaching locus while being pressed against the location to be processed from below. 
     Besides, in the case where the actual locus is more reliably made to coincide with the teaching locus, the hemming robot  30  is taught to bring the fourth processing surface  17  (or the first processing surface  14 ) parallel to the axis SL of the roller  10  into contact with a lower end of the guide portion  24  of the upper die  21 , as shown in  FIG. 7 . More specifically, the upper die  21  having the guide portion  24  whose lower end portion is formed in the shape corresponding to the teaching locus is prepared. Then, when the robot arm  31  is drawn up after moving the roller  10  such that the fourth processing surface  17  (or the first processing surface  14 ) is located directly below the guide portion  24 , the roller head  4  is pulled upward due to the urging force of the spring  35 , and the fourth processing surface  17  (or the first processing surface  14 ) comes into contact with the lower end of the guide portion  24 . When the fourth processing surface  17  (or the first processing surface  14 ) thus comes into contact with the lower end of the guide portion  24 , the roller  10  naturally assumes such a posture that the axis SL thereof is substantially parallel to the outer panel  50 . In this state, the fifth processing surface  18  (or the third processing surface  16 ) can be rolled along the teaching locus by moving the roller  10  with the roller  10  held in contact with the guide portion  24 , while maintaining such a posture that the axis SL is substantially parallel to the outer panel  50 . 
     —Roller Hemming Processing Method— 
     By the way, as shown in the aforementioned  FIG. 2C , it is common to use press hemming processing in the case where hemming coupling is performed between the outer panel  50  and the inner panel  60  by bending the hemming flange  51  provided at the edge portion  50   a  of the outer panel  50  in such a manner as to envelop the inner flange  61  provided at the edge portion  60   a  of the inner panel  60 . However, press hemming processing requires a relatively expensive hydraulic press molding device and a processing device as a dedicated facility, so the cost of processing may increase. 
     Thus, in the present embodiment of the disclosure, the roller hemming processing method is used. However, with a view to facilitating the understanding of the disclosure, the possibilities peculiar to the case where hemming coupling is performed in the vehicular sun roof  40  and the possibilities in the case where hemming coupling as shown in  FIG. 2C  is performed through the use of the roller  110  (see  FIG. 10B ) according to the related art, which has only the processing surface  114  parallel to the axis SL, will be described prior to the description of the roller hemming processing method according to the present embodiment of the disclosure. 
     In roller hemming processing, as shown in  FIG. 10A , it is common to perform hemming coupling between the outer panel  150  and the inner panel  160  by rolling the processing surface  114  while pressing this processing surface against the hemming flange  151  after inserting the edge portion of the inner panel  160  into the hemming flange  151  bent into the shape of a hook (folded back by 180°), as indicated by the blank arrow. However, in the vehicular sun roof  40 , as described above, the outer panel  50  is stacked on the inner panel  60  (see  FIG. 2B ) in such a manner as to insert the rectangular cylinder-like flanges  51 ,  52 ,  53  and  54  into the inner sides of the rectangular cylinder-like flanges  61 ,  62 ,  63  and  64  respectively, so it is difficult to insert the edge portion  60   a  of the inner panel  60  into the hemming flange  51  bent into the shape of a hook. Therefore, the hemming flange  51  provided at the edge portion  50   a  of the outer panel  50  must be subjected to hemming processing from a state where there is no trigger for bending. 
     Besides, a state where the inner flange  161  provided at the edge portion of the inner panel  160  is inserted in the hemming flange  151  bent into the shape of a hook is assumed to have been created. However, when an attempt is made to mold a space enveloping the inner flange  161  by the processing surface  114  parallel to the axis SL of the roller  110 , the processing surface  114  must be diagonally pressed against the hemming flange  151  bent back toward the inner flange  161  side at a right angle, as shown in  FIG. 10B . In other words, the roller  110  must be in such a state that the axis SL thereof is inclined with respect to the outer panel  150 , so there is also a possibility of interference between the receiving pedestal  125  for the inner panel  160  and the roller  110 . 
     Furthermore, when an attempt is made to process the hemming flange  151  folded back toward the inner flange  161  side at a right angle just once through the pressing and rolling of the processing surface  114  (see the blank arrow in  FIG. 10C ), the leading end of the hemming flange  151  and the inner panel  160  interfere with each other as shown in  FIG. 10C , so it may become difficult to mold the hem portion (the leading end portion that is in close contact with the inner panel  160 ). 
     Thus, in the roller hemming processing method according to the present embodiment of the disclosure, the first processing surface  14 , the second processing surface  15 , the third processing surface  16 , the fourth processing surface  17  and the fifth processing surface  18 , which are different from one another in angle of inclination and direction of inclination with respect to the axis SL of the roller  10 , are selectively used in accordance with the stage of processing. In concrete terms, the roller hemming processing method according to the present embodiment of the disclosure includes the following first to fourth processes. 
     (1) In the first process, the edge portion  50   a  of the outer panel  50  is bound from above with the outer panel  50  stacked on the inner panel  60  such that the hemming flange  51  and the inner flange  61  overlap with each other on the roof font side and the roof rear side, and the outer panel  50  and the inner panel  60  are fixed to each other such that the region of the hemming flange  51  that overlaps with the inner flange  61  is bound from the roof front side. 
     (2) In the second process, the selected processing surfaces other than the second processing surface  15 , namely, the third processing surface  16 , the fifth processing surface  18  and the fourth processing surface  17  are used in a stepwise manner such that the angle of inclination with respect to the axis SL of the roller  10  decreases. Thus, a pre-processed portion  70  that is obtained by bending a region  51   a  of the hemming flange  51  that protrudes below the inner flange  61  toward the roof rear side in such a manner as to substantially form a right angle with the inner flange  61  is molded (see  FIGS. 8A to 8C ). 
     (3) In the third process, a region  70   a  of the pre-processed portion  70  that protrudes more toward the roof rear side than the inner flange  61  is inclined diagonally upward (toward the inner panel  60  side) within such a range as not to come into contact with the inner panel  60 , through the use of the second processing surface  15  pressed by a first pressing amount (see  FIG. 8D ). 
     (4) In the fourth process, a region  70   b  of the pre-processed portion  70  that is inclined diagonally upward is molded into an inclined wall portion  71  that is inclined diagonally upward at 49° (a predetermined angle) and has an upper end in contact with the inner panel  60 , and a hem portion  72  that extends toward the roof rear side from an upper end of the inclined wall portion  71  and that is in close contact with the inner panel  60 , through the simultaneous use of the first processing surface  14  and the second processing surface  15 , which are pressed by a second pressing amount that is larger than the first pressing amount (see  FIG. 8E ). 
     The respective processes will be described hereinafter in detail. 
     (1) First Process 
     First of all, after the first lower die  25  and the second lower die  26 , which correspond to the sun roof  40  to be processed, are attached to the turning mechanism portion  27  through the use of the robot arm  31 , the turning mechanism portion  27  is turned in accordance with the gradient of the sun roof  40 . Subsequently, the inner panel  60  is placed on the first lower die  25  and the second lower die  26 . Subsequently, the outer panel  50  is stacked on the inner panel  60  while inserting the rectangular cylinder-like flanges  51 ,  52 ,  53  and  54  into the inner sides of the rectangular cylinder-like flanges  61 ,  62 ,  63  and  64  respectively. Thus, as shown in  FIG. 2B , the outer panel  50  is stacked on the inner panel  60  such that the hemming flange  51  and the inner flange  61  overlap with each other on the roof front side and the roof rear side. 
     In this state, positioning is carried out by the positioning pins  28 , and the outer panel  50  and the inner panel  60  are integrally pinned down by the clamp units  29  at edge portions that define front and lateral ends of the opening portion  55  of the outer panel  50 . Subsequently, the upper die  21  corresponding to the sun roof  40  to be processed is placed on the outer panel  50  with the positioning pins serving as references, through the use of the robot arm  31 . Thus, the outer panel  50  and the inner panel  60  are sandwiched between the pad  22  and the second lower die  26 . Also, the edge portion  50   a  of the outer panel  50  is bound from above by the hemming die  23 , and the region of the hemming flange  51  that overlaps with the inner flange  61  is bound from the roof front side by the guide portion  24 . In this state, the outer panel  50  and the inner panel  60  are integrally fixed to the fixing jig  20 . 
     (2) Second Process 
     In the second process, as described above, the pre-processed portion  70  that is obtained by bending the region (hereinafter referred to also as a first region)  51   a  of the hemming flange  51  that protrudes below the inner flange  61  toward the roof rear side in such a manner as to form a right angle with the inner flange  61  is molded. In this case, a strain is generated when the bending amount in each bending cycle is large. Therefore, the bending amount in each bending cycle is set equal to or smaller than a predetermined threshold angle (e.g., 40°), and the pre-processed portion  70  is molded by repeating bending processing three times. More specifically, the hemming robot  30  is taught to mold the pre-processed portion  70  by using the selected processing surfaces other than the second processing surface  15 , namely, the third processing surface  16 , the fourth processing surface  17  (which can be replaced with the first processing surface  14 ) and the fifth processing surface  18  in a stepwise manner such that the angle of inclination with respect to the axis SL of the roller  10  decreases, that is, by using the third processing surface  16  that is inclined at 60° with respect to the axis SL, the fifth processing surface  18  that is inclined at 30° with respect to the axis SL, and the fourth processing surface  17  that is parallel to the axis SL (inclined at an angle of 0°) in this sequence. 
     First of all, the hemming robot  30  selects the third processing surface  16  as a processing surface and presses the third processing surface  16  against the first region  51   a  from below in such a posture that the axis SL is substantially parallel to the outer panel  50  as shown in  FIG. 8A . In this case, as is the case with the aforementioned  FIG. 7 , the first processing surface  14  formed closer to the shaft portion  12  side than the third processing surface  16  is brought into contact with the lower end of the guide portion  24 . Then, when the roller  10  is moved along the edge portion  50   a  of the outer panel  50  while holding the first processing surface  14  in contact with (in touch with) the lower end of the guide portion  24 , the third processing surface  16  rolls while being pressed against the first region  51   a , and the first region  51   a  is inclined toward the roof rear side at 30° with the inner flange  61  serving as a core bar. 
     Subsequently, the hemming robot  30  selects the fifth processing surface  18  as a processing surface, inverts the roller  10  by rotating the leading end portion  31   a  of the robot arm  31  by 180°, and presses the fifth processing surface  18  against the first region  51   a  inclined at 30° from below in such a posture that the axis SL is substantially parallel to the outer panel  50  as shown in  FIG. 8B . In this case, as is the case with the aforementioned  FIG. 7 , the fourth processing surface  17  formed closer to the shaft portion  12  side than the fifth processing surface  18  is brought into contact with the lower end of the guide portion  24 . Then, when the roller  10  is moved along the edge portion  50   a  of the outer panel  50  while holding the fourth processing surface  17  in contact with the lower end of the guide portion  24 , the fifth processing surface  18  rolls while being pressed against the first region  51   a , and the first region  51   a  is inclined toward the roof rear side at 60° with the inner flange  61  serving as a core bar. 
     Subsequently, the hemming robot  30  selects the fourth processing surface  17  as a processing surface and presses a leading end portion of the fourth processing surface  17  against the first region  51   a  inclined at 60° from below in such a posture that the axis SL is substantially parallel to the outer panel  50  as shown in  FIG. 8C . In this case, a base end portion (a region close to the shaft portion  12 ) of the fourth processing surface  17  is brought into contact with the lower end of the guide portion  24 . Then, when the roller  10  is moved along the edge portion  50   a  of the outer panel  50  while holding the base end portion of the fourth processing surface  17  in contact with the lower end of the guide portion  24 , the fourth processing surface  17  rolls while being pressed against the first region  51   a , and the first region  51   a  is inclined toward the roof rear side at 90° with the inner flange  61  serving as a core bar. Thus, the pre-processed portion  70  is molded. 
     As described hitherto, in the second process, the pre-processed portion  70  is molded by setting the bending amount in each bending cycle to 30° and repeating bending processing three times. Thus, a strain can be restrained from being generated when the bending amount in each bending cycle is large. Besides, the region of the hemming flange  51  that overlaps with the inner flange  61  is bound from the roof front side by the guide portion  24 . Thus, the hemming flange  51  can be restrained from swelling toward the roof front side in bending the first region  51   a . Moreover, the third processing surface  16  (or the fifth processing surface  18  or the fourth processing surface  17 ) is rolled while holding the first processing surface  14  (or the fourth processing surface  17 ) against the lower end of the guide portion  24 . Thus, the hemming flange  51  can be accurately bent along the teaching locus from a state where there is no trigger for bending. 
     (3) Third Process 
     In the third process, as described above, the region (hereinafter referred to also as a second region)  70   a  of the pre-processed portion  70  that protrudes more toward the roof rear side than the inner flange  61  is inclined diagonally upward (in such a manner as to extend upward as the distance to the roof rear side decreases) through the use of the second processing surface  15 . It should be noted herein that when the region  70   a  is inclined at once through the use of the second processing surface  15  that is inclined at 49° with respect to the axis SL, the bending amount in each bending cycle exceeds 40°. Therefore, a strain is generated, and the leading end of the pre-processed portion  70  and the inner panel  60  interfere with each other. Accordingly, in the third process, only preliminary bending processing is carried out in preparation for the fourth process. 
     More specifically, the hemming robot  30  selects the second processing surface  15  as a processing surface, inverts the roller  10  by rotating the leading end portion  31   a  of the robot arm  31  by 180°, presses the second processing surface  15  against the second region  70   a  from below by the first pressing amount in such a posture that the axis SL is substantially parallel to the outer panel  50 , as shown in  FIG. 8D . This “first pressing amount” is set to a value at which the second region  70   a  is inclined diagonally upward within such a range as not to come into contact with the inner panel  60 , more concretely, to a value at which the second region  70   a  is inclined diagonally upward at 30°. Then, when the roller  10  is moved along the edge portion  50   a  of the outer panel  50 , the second processing surface  15  rolls while being pressed against the second region  70   a  by the first pressing amount, and the second region  70   a  is inclined diagonally upward at 30° with the inner flange  61  serving as a core bar. Incidentally, the second region  70   a  inclined diagonally upward at 30° will be referred to hereinafter as a third region  70   b.    
     (4) Fourth Process 
     In the fourth process, as described above, the third region  70   b  is molded into the inclined wall portion  71  that is inclined diagonally upward at 49° and that has an upper end in contact with the inner panel  60 , and the hem portion  72  that extends toward the roof rear side from the upper end of the inclined wall portion  71  to be in close contact with the inner panel  60 . The hemming robot  30  is taught to select the first processing surface  14  and the second processing surface  15  as processing surfaces, and simultaneously press the first processing surface  14  and the second processing surface  15  against the third region  70   b  from below by the second pressing amount that is larger than the first pressing amount, in such a posture that the axis SL is substantially parallel to the outer panel  50 , as shown in  FIG. 8E . Then, when the roller  10  is moved along the edge portion  50   a  of the outer panel  50 , the second processing surface  15  rolls while being pressed against the third region  70   b , and a base end portion of the third region  70   b  inclined diagonally upward at 30°, and the inclined wall portion  71  that is inclined diagonally upward at 49° and that has the upper end in contact with the inner panel  60  are molded, with the inner flange  61  serving as a core bar. At the same time, a leading end portion of the third region  70   b  inclined diagonally upward at 30° is sandwiched between the edge portion  50   a  of the outer panel  50  kept from moving upward by the hemming die  23  (more precisely, the edge portion  50   a  of the inner panel  60 ) and the first processing surface  14 , and the hem portion  72  that extends toward the roof rear side from the upper end of the inclined wall portion  71  and that is in close contact with the inner panel  60  is molded. 
     The inclined wall portion  71  thus molded is substantially in a state where the edge portion  50   a  of the outer panel  50  is folded back beyond 180°. However, in the roller hemming processing method according to the present embodiment of the disclosure and the roller hemming processing device according to the present embodiment of the disclosure, the second processing surface  15  as a tapered surface that narrows toward the base end side (the shaft portion  12  side) of the roller  10  is used. Thus, unlike the case shown in  FIG. 10B , this inclined wall portion  71  can be molded while maintaining such a posture that the axis SL is substantially parallel to the outer panel  50 . Accordingly, the first lower die  25 , which receives the inner panel  60 , and the roller  10  can be restrained from interfering with each other. 
     Moreover, as described above, the protrusion length of the third processing surface  16  from the first processing surface  14  is relatively short. Thus, the first lower die  25 , which receives the inner panel  60 , and the roller  10  can be more effectively restrained from interfering with each other in the fourth process. 
     Incidentally, unlike the second process in which the hemming flange  51  is subjected to bending processing from the state where there is no trigger for bending, the first processing surface  14  and the second processing surface  15  can be rolled with somewhat high accuracy along the teaching locus, even if the roller  10  is not moved while being held in contact with the lower end of the guide portion  24 , in the third process in which preliminary bending processing is carried out and the fourth process in which finishing is carried out. 
     Other Embodiments 
     The disclosure is not limited to the aforementioned embodiment thereof but can be carried out in various other modes without departing from the spirit or main features thereof. 
     In the aforementioned embodiment of the disclosure, the roller  10  having the first processing surface  14 , the second processing surface  15 , the third processing surface  16 , the fourth processing surface  17  and the fifth processing surface  18  is used, but the disclosure is not limited thereto as long as the roller  10  has the first processing surface  14 , the second processing surface  15 , and the two or more tapered processing surfaces  16  and  18  that are inclined at different angles. For example, as shown in  FIG. 9 , a roller  10 A that dispenses with the fourth processing surface  17  may be used. In this case, the first processing surface  14  may be used instead of the fourth processing surface  17 , in molding the pre-processed portion  70  from the first region  51   a  inclined at 60° in the second process. 
     Besides, in the aforementioned embodiment of the disclosure, the third processing surface  16  is formed on the first roller portion  11 , and the fifth processing surface  18  is formed on the second roller portion  13 , but the disclosure is not limited thereto as long as the first lower die  25  and the roller  10  do not interfere with each other in the fourth process. For example, the third processing surface  16  may be formed on a leading end side of the fourth processing surface  17 , and the fifth processing surface  18  may be formed on a leading end side of the first processing surface  14 . 
     Furthermore, in the aforementioned embodiment of the disclosure, the second processing surface  15  is formed in such a manner as to be inclined at 49° with respect to the axis SL, but the disclosure is not limited thereto. The second processing surface  15  may be inclined at an appropriate angle in accordance with the finished shape of the vehicular sun roof  40 . 
     Besides, in the aforementioned embodiment of the disclosure, the pre-processed portion  70  is molded by inclining the third processing surface  16  at 60° with respect to the axis SL, inclining the fifth processing surface  18  at 30° with respect to the axis SL, setting the bending amount in each bending cycle to 30° and repeating bending processing three times, but the disclosure is not limited thereto as long as the bending amount in each bending cycle is set equal to or smaller than the predetermined threshold angle (40° in the aforementioned embodiment of the disclosure). The pre-processed portion  70  may be molded by repeating bending processing four or more times. For example, the pre-processed portion  70  may be molded by inclining the third processing surface  16  at 67.5° with respect to the axis SL, inclining the fifth processing surface  18  at 22.5° with respect to the axis SL, further providing a sixth processing surface (not shown) as a tapered surface that is inclined at 45° with respect to the axis SL in such a manner as to narrow toward a leading end side from the fifth processing surface  18 , and repeating bending processing four times with the bending amount in each bending cycle set to 22.5° in the sequence of the third processing surface  16 , the sixth processing surface, the fifth processing surface  18  and the fourth processing surface  17 . 
     Furthermore, in the aforementioned embodiment of the disclosure, the processing surface is pressed against the hemming flange  51  from below with the outer panel  50  stacked on the inner panel  60 , but the disclosure is not limited thereto. For example, the processing surface may be pressed against the hemming flange  51  from above with the inner panel  60  stacked on the outer panel  50 . 
     As described hitherto, the above-mentioned embodiment of the disclosure is nothing more than a mere exemplification in every respect and should not be interpreted in a restrictive manner. Furthermore, all the modifications and alterations pertaining to a scope equivalent to the claims fall within the scope of the disclosure. 
     According to the disclosure, hemming coupling can be performed between one panel and the other panel by bending a flange provided on one panel in such a manner as to envelop a flange provided on the other panel even from a state where there is no trigger for bending, while reducing the cost of processing. Therefore, it is quite useful to apply the disclosure to a roller hemming processing method and a roller hemming processing device.