JP2011194998A - Method of manufacturing automobile wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To propose a method of manufacturing an automobile wheel which suppresses occurrence of thickening on the outside in the radial direction of a front flange section, when molding the front flange section in which an annular front circumferential part and an annular rear circumferential part are in surface-to-surface contact with each other.SOLUTION: The method of manufacturing the automobile wheel includes a sequence of bending and compression processes in which, after an outermost circumferential annular part 43 of a disk-shaped preliminary mold body 41 is bent rearwardly along both sides, the outermost circumferential annular part 43 is brought into surface-to-surface contact with a rear surface 46a of a front outer circumferential annular part 46 by folding back the outermost circumferential annular part toward the inside in the radial direction, and subsequently the outermost circumferential annular part 43 and the front outer circumferential annular part 46 are compressed in a plate thickness direction. Therefore, extensional deformation caused by the process of compression in the plate thickness direction in the bending and compression processes can easily be caused only toward the inside in the radial direction, thereby suppressing the thickening caused by extensional deformation toward the outside in the radial direction. This suppresses occurrence of burr, wrinkles or the like, thereby allowing the front flange section to be molded precisely and stably.

Description

  The present invention relates to a method for manufacturing a wheel for an automobile which is integrated by welding a wheel rim to which a tire is mounted and a wheel disc to which an axle is connected.

  There is a so-called two-piece type of automobile wheel, which is formed by welding a substantially cylindrical wheel rim and a substantially disk-shaped wheel disk. As this two-piece type automobile wheel, a full face type wheel having a configuration in which a front flange portion is formed on the outer peripheral edge of a wheel disk is known.

  For example, Patent Document 1 proposes an example of the above-described full-face type configuration. Specifically, the wheel rim includes a front bead seat portion at one opening edge and a back flange portion at the other opening edge. And the wheel disk is the structure provided with the front side flange part of the cross-sectional substantially U shape formed by folding back in the outer peripheral edge part to the back side. Then, the full-face type automotive wheel is formed by welding the opening end portion of the front bead seat portion of the wheel rim and the inner peripheral end portion of the front flange portion of the wheel disc in the circumferential direction. ing. Such a full-face type automobile wheel has an excellent advantage that a high design property can be exhibited because a large design surface of the wheel disk can be secured.

  Here, as a step of forming the front side flange portion of the wheel disc, for example, as shown in FIG. 7, the tip peripheral portion 103 of the outer peripheral end portion 102 of the disc-shaped preform 101 for forming the wheel disc is used. The front flange portion 109 folded in a curved shape can be formed by bending the outer peripheral end portion 102 to the back side after being bent to the back side. More specifically, as shown in FIG. 7A, the outer peripheral end portion 102 of the disk-shaped pre-formed body 101 is sandwiched between the upper support mold 111 and the lower support mold 112, and the outer peripheral end portion of the disk-shaped pre-formed body 101. The front end peripheral portion 103 of 102 is bent backward by a ring-shaped punch 113. Next, as shown in FIG. 7B, the bent intermediate peripheral portion 104 connected to the tip peripheral portion 103 of the outer peripheral end portion 102 is bent obliquely to the back side. That is, a ring-shaped punch having a predetermined inclined surface portion 118, wherein the front side peripheral portion 105 connected to the bent intermediate peripheral portion 104 of the outer peripheral end portion 102 is sandwiched between the upper support die 115 and the lower support die 116. The bent intermediate peripheral portion 104 is bent by 117. Next, as shown in FIG. 7C, the front side peripheral portion 105 of the outer peripheral end portion 102 is sandwiched between the upper support die 120 and the lower support die 121, and the outer peripheral end portion 102 is bent by the ring-shaped punch 122. The intermediate peripheral portion 104 is bent to the back side. As a result, a curved front flange portion 109 is formed. As such a molding method, for example, the molding method disclosed in Patent Document 2 can be applied.

  Although not shown in the drawings, the same front flange can be obtained by performing a process of bending the outer peripheral end of the disk-shaped preform to the back side and then performing a process of bending the distal end of the outer peripheral end inward in the radial direction. It is possible to mold the part.

Japanese Patent Application Laid-Open No. 11-42901 Japanese Patent Laid-Open No. 11-226648 (see FIGS. 1 and 3)

  By the way, in the structure of the above-mentioned patent document 1, the front side flange portion folded back in a curved shape is likely to be repeatedly elastically deformed due to a load acting during traveling of the automobile, and stress concentration is likely to occur. Furthermore, since the front flange portion is formed by being folded back by pressing or the like as described above, residual stress is generated at the curved outermost peripheral portion. Due to the residual stress and the stress concentration due to the load described above, the durability of the front flange portion is limited.

  As a configuration for solving such a problem, the present inventors have folded the front flange portion provided on the outer peripheral edge of the wheel disc from the annular surface peripheral portion on the design surface side to the back side from the annular surface peripheral portion. In addition, an automobile wheel having a configuration including an annular back peripheral portion that is coupled radially inward and is in surface contact with the back side surface of the annular front peripheral portion is proposed (see FIG. 1). As a method of forming such a front flange portion, for example, a process of forming a substantially U-shaped cross-section folded back as described above (see FIG. 7), and then pressing in the front and back directions (FIG. (Not shown). Thereby, the front side flange part which surface-contacted the cyclic | annular front peripheral part and the cyclic | annular back peripheral part can be shape | molded.

  Here, the step of forming the front flange portion is usually set so that the step of forming a substantially U-shaped cross section and the step of pressing in the front and back direction are performed separately. This is because, in general, as a metal processing method, by performing processing in a plurality of stages, the amount of deformation in each processing stage is reduced, and generation of cracks and wrinkles is suppressed. However, as described above, the outermost peripheral portion that connects the annular front peripheral portion and the annular back peripheral portion when performing the step of forming a substantially U-shaped cross section and then pressing the front and back directions. However, when it tries to extend outward in the radial direction, a surplus portion is generated at the outermost peripheral edge portion. Due to this surplus, the movement of the mold or the like is hindered, and the annular front peripheral portion and the annular rear peripheral portion cannot be sufficiently pressed together, reducing dimensional accuracy, generating burrs, and generating wrinkles, etc. This is likely to cause molding defects. Therefore, a method for suppressing the occurrence of such a surplus as much as possible is required.

  The present invention relates to an automotive wheel capable of suppressing a surplus in the radial direction of a front side flange portion that is in surface contact with an annular front peripheral portion and an annular rear peripheral portion, and suppressing the occurrence of molding defects associated therewith. A manufacturing method is proposed.

  As the present invention, a wheel rim in which a rear flange portion is formed at one opening edge and a front bead seat portion is formed at the other opening edge, and a wheel disc having a front flange portion formed at an outer peripheral edge portion, In the method for manufacturing a wheel for an automobile equipped with, a pre-bending process step of bending the outermost peripheral ring portion provided in a disk-shaped preform for forming a wheel disc to the back side along the front and back direction, and the back side By folding the outermost ring part bent to the inside in the radial direction, the outermost ring part is brought into surface contact with the back side surface of the outer peripheral ring part on the front side of the design surface that is coupled to the outermost ring part. A series of bending compression processing steps in which the outermost ring part and the front outer ring part are compressed and pressed in the thickness direction, and the outermost ring part and the front outer ring part that are in pressure contact are integrally inclined to the front. Sequential bending process By executing, a front side flange portion having an annular front peripheral portion formed by the front outer peripheral annular portion and an annular back peripheral portion formed by the outermost peripheral annular portion and tilting outward is provided on the outer side of the wheel disk. It is the manufacturing method of the wheel for motor vehicles characterized by forming in a peripheral part.

  According to this manufacturing method, the outermost peripheral ring portion is folded back radially inward by the bending compression process, and further compressed in the plate thickness direction. It can be deformed toward the inside in the radial direction. Thereby, since the deformation | transformation produced toward a radial direction outer side by the compression to a plate | board thickness direction can be suppressed, it is possible to produce a surplus in the radial direction outer side part of an outermost periphery ring part (front side flange part) by the said compression. Can be suppressed. If it explains in full detail, the process which compresses in a plate | board thickness direction will produce the deformation | transformation which expand | extends in the plate | board thickness direction with the compression deformation. This extension deformation occurs in the radial inner and outer directions because deformation in the circumferential direction is limited by the shape effect of the outermost peripheral ring portion. Here, in the process of turning the outermost ring portion radially inward, deformation proceeds in a direction toward the radially inner side. Then, by performing the process of folding inward in the radial direction and the process of compressing in the plate thickness direction, the expansion deformation caused by the process of compressing occurs in accordance with the progress direction of the deformation generated by the process of folding back inward in the radial direction. Can be. Thereby, it can suppress as much as possible that it deform | transforms to a radial direction outer side in the process compressed to a plate | board thickness direction, and can suppress that the surplus occurs in the radial direction outer side part of an outermost periphery ring part (front side flange part). . Along with this, the movement of the mold or the like can be performed appropriately, so that the outermost peripheral ring portion and the front outer peripheral ring portion can be press-contacted to form a desired shape. And generation | occurrence | production of a burr | flash, wrinkles, etc. can also be suppressed.

  Temporarily, when the outermost peripheral ring portion is folded back inward in the radial direction and the outermost peripheral ring portion and the front outer peripheral ring portion are in surface contact, one end processing is stopped, and then the outermost peripheral ring portion and the front outer peripheral ring portion are plated. When compressing in the thickness direction, deformation due to the compression tends to occur outward in the radial direction. This is because the deformation due to the process of compressing in the plate thickness direction cannot follow the deformation due to the process of turning back inward in the radial direction. As described above, when the process of turning back inward in the radial direction and the process of compressing in the plate thickness direction are discontinuous, the occurrence of the above-mentioned surplus cannot be suppressed and the effects of the present invention are not achieved.

  In the automobile wheel manufacturing method described above, the bending compression processing step includes an upper pressure contact mold having a pressure contact surface portion that presses in contact with the front side surface of the front side outer peripheral ring portion on the design surface side, and the back side. A curved surface portion for folding the bent outermost ring portion radially inward, and a folded surface portion that extends radially inward from the curved surface portion and faces the pressure contact surface portion of the upper pressure contact mold. By moving the lower folding mold from the separation position where the outermost peripheral ring part bent to the back side and the front side outer ring part are not pinched in a direction relatively close to each other along the front and back direction, The ring part is folded back inward in the radial direction so as to follow the curved machining surface part and the folding machining surface part of the lower folding mold, and the position is changed to a contact machining position where the ring part comes into surface contact with the back side surface of the front outer circumferential ring part. And move the outermost ring and front outer ring How to compress so that positioned converted into pressure contact processing position for pressing into is proposed.

  In such a manufacturing method, the process of turning the outermost peripheral ring part back radially inward and the process of compressing in the plate thickness direction are stopped without stopping by the cooperation of the upper pressure contact mold and the lower folding mold. Can be done continuously. Thereby, it is possible to appropriately exhibit the above-described effect of the present invention that it is possible to suppress the occurrence of a surplus in the radially outer portion of the outermost peripheral ring portion (front flange portion). Here, since the lower folding mold is a combination of the curved surface portion and the folded surface portion, by deforming the outermost peripheral ring portion so as to follow the curved surface portion and the folded surface portion, Deformation caused by folding the outermost ring portion radially inward and deformation caused by compression in the plate thickness direction can be continuously generated. Thereby, in the process of compressing in the plate thickness direction, the outermost peripheral ring portion is easily deformed inward in the radial direction, so that it is possible to suppress the occurrence of molding defects due to the above-described surplus as much as possible.

  In addition, as relative movement for converting the position of the upper press-contacting die and the lower bending die from the separated position to the press-working position, both the upper press-contacting die and the lower bending die are moved. Alternatively, only one of them may be moved.

  In the automobile wheel manufacturing method described above, the bending compression processing step is positioned so that the compression processing position has a compression ratio of 80% to 95% with respect to the contact processing position. Such a method is proposed. Here, the compression rate indicates the position interval between the upper press-bonding die and the lower bent die at the press-working position on the basis of the position interval between the upper press-contacting die and the lower bent die at the contact processing position. It is a ratio.

  If the compression ratio is less than 80%, compression deformation in the plate thickness direction increases, so that the outermost peripheral ring portion is likely to be deformed toward the radially outer side, and the deformation toward the radially outer side is also increased. easy. Therefore, the effect which suppresses the surplus part which generate | occur | produces in the radial direction outer side part of an outermost periphery ring part (front side flange part) will reduce. On the other hand, if the compression rate is greater than 95%, it is difficult to sufficiently press the outermost ring portion and the front outer ring portion, and there is a concern that a gap may be formed between them. From the above, by setting the compression rate within the range of 80% or more and 95% or less, a desired front flange portion can be formed appropriately.

  The compression rate is preferably 85% or more and 90% or less, whereby the above-described effects can be more stably generated.

  The automobile wheel manufacturing method of the present invention, as described above, after bending the outermost ring part of the disk-shaped preform into the back side along the front and back direction, the outermost ring part is turned to the front side on the design surface side. Folded inward in the radial direction so as to come into surface contact with the back side surface of the outer peripheral ring part, and further performed a series of bending compression processing steps to continuously compress the outermost peripheral ring part and the front side outer peripheral ring part in the thickness direction, Thereafter, the desired front side flange portion is formed on the outer peripheral edge portion of the wheel disk by inclining to the front side. According to this manufacturing method, since the expansion deformation caused by the compression in the plate thickness direction in the bending compression process can be easily generated toward the radial inner side, the outermost peripheral ring generated by the radial deformation outward. It can suppress that the surplus occurs in the radial direction outer side part of a part (front side flange part). Thereby, while being able to shape | mold an outermost periphery ring part in a desired dimension shape, since generation | occurrence | production of a burr | flash, wrinkles, etc. can be suppressed as much as possible, generation | occurrence | production of a shaping | molding malfunction can be suppressed.

  In the automobile wheel manufacturing method described above, the bending compression processing step changes the position of the upper pressure contact mold and the lower bending mold from the separated position to the contact processing position. Is turned inward in the radial direction to bring it into surface contact with the outer peripheral ring portion, and the position of the outermost peripheral ring portion and the front outer peripheral ring portion in the plate thickness direction is continuously changed from the contact processing position to the pressure contact processing position. In the case of pressure contact, the outermost peripheral ring part is turned back in the radial direction and the outermost peripheral ring part and the front outer peripheral ring part are in the plate thickness direction by the cooperation of the upper pressure contact mold and the lower bending mold. The above-described effect of the present invention can suppress the occurrence of a surplus in the radially outer portion of the outermost ring portion (front flange portion). Can be demonstrated properly.

  In the automobile wheel manufacturing method described above, the bending compression processing step is positioned so that the pressure-contact processing position has a compression ratio of 80% to 95% with respect to the contact processing position. In such a case, the effect of the present invention that suppresses the occurrence of the above-described surplus is further improved.

1 is a longitudinal sectional view of an automotive wheel 1 according to a first embodiment. It is an enlarged view showing the X section in FIG. It is explanatory drawing showing the pre-bending process process which bends the outermost periphery ring part 43 of the disk shaped preform 41 along the front and back direction. It is explanatory drawing showing the process in which the outermost periphery ring part 43 is return | folded to radial inside by a bending compression process. It is explanatory drawing showing the process which presses the outermost periphery ring part 43 which continues from FIG. 4 to a plate | board thickness direction. It is explanatory drawing showing an (A) inclination bending process and a (B) groove part manufacturing process. It is explanatory drawing showing the process of shape | molding the conventional curved front side flange part.

An automotive wheel 1 according to this embodiment will be described with reference to FIGS.
The vehicle wheel 1 is a so-called two-piece type steel wheel formed by joining a wheel rim 2 and a wheel disc 3 each formed from a steel flat plate. And it is the structure of a full face type provided with the front side flange part 31 in the outer periphery part of the wheel disc 3. FIG. In the present embodiment, the direction from the rear surface side of the wheel disk 3 toward the design surface side (the direction from the left to the right in FIG. 1) is the front direction, and the reverse direction is the reverse direction. In addition, the direction toward the central axis L of the automobile wheel 1 along the wheel radial direction is defined as a radially inward direction, and the opposite direction is defined as a radially outward direction. The design surfaces of the automobile wheel 1 and the wheel disc 3 are surfaces facing the outside of the automobile when attached to the automobile.

  The wheel rim 2 described above has a substantially cylindrical shape, and a back flange portion 12 that supports a bead on the back side of the tire from the side is provided on one (back side) opening edge portion thereof. The back side flange seat 12 is coupled with a back side beat seat 14 for seating and supporting a bead on the back side of the tire. Further, a front side beat seat portion 13 for seating and supporting a bead on the front side of the tire is provided at the opening edge of the other (front side) of the wheel rim 2. That is, the front side flange portion 31 is not formed on the other opening (front side) opening edge of the wheel rim 2, and the front side opening edge is constituted by the annular front side bead seat portion 13 along the front and back direction. ing. Between the front and back bead sheet portions 13 and 14, a well portion 15 is provided for dropping the front and back bead of the tire when the tire is mounted.

  On the other hand, the wheel disc 3 described above has a substantially disk shape, and a hub mounting portion 21 connected to the hub of the axle is provided in the center thereof, and a front flange portion 31 is formed around the outer peripheral edge portion. And the spoke part 22 along the radial direction is provided in the circumferential direction at equal intervals so that both may be connected between the hub attachment part 21 and the front side flange part 31. As shown in FIG. Further, a decoration hole 25 is provided between the spoke portions 22 adjacent to each other.

  A hub hole 27 is formed at the center of the hub attachment portion 21, and a plurality of bolt holes 28 are located at the outer side in the radial direction of the hub hole 27 and evenly spaced from each other in the circumferential direction. Is provided. Each part of the wheel disc 3 is formed concentrically with the central axis L of the wheel disc 3 as the center. The spoke portion 22 is formed so as to rise from the peripheral edge of the hub attachment portion 21 to the front side. And the outer end of each spoke part 22 and the front side flange part 31 are smoothly coupled.

  As shown in FIG. 2, the front flange portion 31 is folded back from the annular surface peripheral portion 32 to the back surface side of the design surface side formed from the outer end of the spoke portion 22. It is comprised from the annular back peripheral part 33 extended in the radial direction inward. The entire surface of the front side surface 33a of the annular back peripheral portion 33 is formed so as to be in surface contact with the back side surface 32a of the annular front peripheral portion 32, and the annular front peripheral portion 32 and the annular back peripheral portion 33 are integrated. Form. Furthermore, the front flange portion 31 is bent and inclined from the proximal end portion (inner peripheral end portion) of the annular outer peripheral portion 32 to the front side. That is, the front side flange portion 31 is inclined to the front side at an inclination angle θ with respect to a radial virtual plane P (plane along the radial direction) orthogonal to the central axis L of the automobile wheel 1. Note that the inclination angle θ of the front flange portion 31 is set to be in the range of 15 degrees or more and 45 degrees or less.

Next, a method for manufacturing the above-described automobile wheel 1 will be described.
The wheel rim 2 is formed by forming a straight cylinder body by butt welding the short sides of a substantially rectangular steel flat plate, and then rotating the cylinder body in the circumferential direction. Molding can be performed by performing so-called roll processing in which pressing is performed by a predetermined mold from both sides. Since a conventional molding method can be applied to the molding of such a wheel rim 2, the description thereof is omitted.

  The wheel disk 3 can be formed by pressing a substantially circular steel flat plate. Specifically, a desired design surface shape is obtained by performing a pressing process in which a center region of the steel flat plate is recessed into a substantially bowl shape and then pressed from both front and back sides by a predetermined die in a plurality of stages. The decorative hole 25, the hub hole 27, the bolt hole 28, the front flange portion 31 and the like are formed. In this way, a desired wheel disk 3 is formed. Here, in the first embodiment, the step of forming the front side flange portion 31 provided on the outer peripheral edge portion of the wheel disk 3 is a main portion of the present invention, and details will be described later. Moreover, since the conventional shaping | molding method can be applied except the process of shaping | molding the front side flange part 31, description is abbreviate | omitted for the detail.

  By thus welding the wheel rim 2 and the wheel disk 3 that are separately molded, the automobile wheel 1 of the first embodiment described above is obtained. More specifically, the front bead seat of the wheel rim 2 is placed on the disc back surface portion 6 (annular groove portion 37 described later) of the wheel disc 3 so that the center axis L of the wheel disc 3 and the wheel rim 2 coincide with each other. The opening end part 13a of the part 13 is abutted and positioned. Then, from the outside of the wheel rim 2 to the entire circumference in the wheel circumferential direction by arc welding so as to integrally join the disc back surface portion 6 of the wheel disc 3 and the opening end portion 13a of the front bead seat portion 13 of the wheel rim 2. Over. By this welding, a welded portion 39 that joins the wheel rim 2 and the wheel disc 3 is formed over the entire circumference in the wheel circumferential direction.

  Next, a method for forming the front flange portion 31 of the wheel disk 3 according to the main part of the present invention will be described with reference to FIGS. In the molding step of molding the wheel disk 3, an intermediate molded body in the middle of molding from the steel flat plate to the wheel disk 3 is represented as a disk-shaped preform 41 according to the present invention.

  In the wheel disk 3 forming step described above, the front flange portion forming step for forming the front flange portion 31 on the outer peripheral edge portion of the disk-shaped preform 41 is performed as shown in FIGS. In this front side flange portion forming step, a preliminary bending step, a bending compression step, an inclined bending step, and a groove portion are sequentially executed.

  The disk-shaped preform 41 described above has a configuration in which an annular plate-shaped annular outer peripheral edge 42 that is substantially orthogonal to the central axis L is provided on the outer peripheral edge thereof as shown in FIG. A process of bending the annular outermost peripheral ring part 43 defined by a predetermined ring width from the outer peripheral end of the annular outer peripheral edge part 42 to the back side is performed by the above-described preliminary bending process. More specifically, the front outer peripheral ring portion 46 of the annular outer peripheral edge portion 42 is positioned and sandwiched by the upper support die 65 and the lower support die 66. Thereafter, as shown in FIG. 3 (B), the outermost periphery projecting outward from the upper support die 65 and the lower support die 66 by moving the ring-shaped punch 67 from the front side to the back side along the central axis L. The ring portion 43 is bent back along the central axis L. Here, the front outer peripheral ring portion 46 of the annular outer peripheral edge portion 42 is an annular portion that is coupled radially inward from the outermost peripheral annular portion 43, and the annular outer peripheral edge portion 42 together with the outermost peripheral annular portion 43. Is configured.

  A folding compression process is performed after the preliminary folding process. The bending compression process is performed by controlling movement of the upper pressure contact mold 71 and the lower bending mold 73 as shown in FIGS. The upper pressure contact die 71 includes a pressure contact surface portion 72 that is in surface contact with and supported by the front side surface 46 b of the front side outer peripheral ring portion 46 of the annular outer peripheral edge portion 42. The lower bending mold 73 includes a folded surface portion 75 that faces the pressure contact surface portion 72 and a curved surface portion 74 that rises in a curved shape from the outer peripheral end of the folded surface portion 75 to the front side. The pressure contact surface portion 72 of the upper pressure contact mold 71 and the folded surface surface portion 75 of the lower bending mold 73 are provided so as to be orthogonal to the central axis L (that is, the above-described radial virtual plane P and parallel).

  As shown in FIG. 4A, the upper press-contacting die 71 and the lower bending die 73 are separated from each other in the front and back direction (vertical direction), and the outermost peripheral ring portion 43 bent to the back side is interposed therebetween. The provided disk-shaped preform 41 is disposed. In this separated position, the front side surface 46 b of the front outer peripheral ring portion 46 of the annular outer peripheral edge portion 42 is supported by the pressure contact surface portion 72 of the upper pressure contact die 71, and the upper pressure contact die 71, the lower bent die 73, Therefore, the annular outer peripheral edge 42 is not clamped. Thereafter, as shown in FIG. 4B, the lower bending mold 73 is moved (raised) from the back side to the front side along the central axis L. Along with this, the outermost peripheral ring portion 43 bent to the back side is folded back radially inward according to the curved surface shape by the curved surface portion 74 of the lower folding mold 73. Then, as shown in FIG. 5C, the outermost peripheral ring portion 43 is folded back to the back side and coupled radially inward so that the front side surface 43a is in surface contact with the back side surface 46a of the front side outer peripheral ring portion 46. It is assumed that it was made form. In this way, the position of the lower bending die 73 that brings the front side surface 43a of the outermost peripheral ring portion 43 into contact with the back side surface 46a of the front side outer peripheral ring portion 46 to make surface contact is the contact processing position according to the present invention.

  Further, the lower bending mold 73 is continuously moved to the front side without stopping at the above-described contact processing position (FIG. 5C), and as shown in FIG. 43 and the front side outer periphery ring part 46 are compressed and pressed in the thickness direction (front and back direction). The position of the lower bending die 73 that is pressure-contacted in this way is the pressure-welding position according to the present invention. Here, the press-contacting position is set according to a compression ratio for compressing the outermost peripheral ring portion 43 and the front outer peripheral ring portion 46 in the plate thickness direction. That is, the distance between the pressure contact surface portion 72 of the upper pressure contact mold 71 and the folded back surface portion 75 of the lower folding mold 73 is 80% or more and 95% or less of the contact processing position as a reference. The pressure welding position is set so as to be in the range. In this example, this compression rate was set to 90%.

  In such a bending compression processing step, the outermost peripheral ring portion 43 is imitated with the curved processing surface portion 74 and the folding processing surface portion 75 of the lower folding mold 73 in the process from the above-described separation position to the contact processing position. In this way, it is folded back inward in the radial direction. In this process, the outermost circumferential ring portion 43 is deformed radially inward, in other words, the deformation direction of the outermost circumferential ring portion 43 is controlled to be directed radially inward. On the other hand, in the process from the contact processing position to the pressure processing position, since compression is performed in the plate thickness direction, the outermost peripheral ring portion 43 extends and deforms in a direction along the radial virtual plane P orthogonal to the plate thickness direction. . Since the outermost ring portion 43 is restricted from extending and deforming in the circumferential direction, it is extended and deformed radially inward or outward. Here, in the present embodiment, as described above, the lower bending die 73 is continuously moved to the pressure processing position without stopping at the contact processing position. It becomes easy to produce the expansion | extension deformation of 43 toward radial inside. This is because the lower bending die 73 is continuously moved from the separation position to the press-working position, so that the expansion deformation of the outermost peripheral ring portion 43 that occurs in the process up to the press-working position is reduced to the contact work position. This is because it can be generated in accordance with the deformation direction of the outermost peripheral ring portion 43 generated in the process (the direction toward the radially inner side). Thereby, since it can suppress as much as possible that the outermost periphery ring part 43 expand | extends and deforms to radial direction outer side by compressing to a plate | board thickness direction, the outermost periphery ring part 43 (front side flange part 31) which arises with this can be suppressed. It is possible to suppress the occurrence of surplus in the radially outer portion of the. Therefore, according to the present embodiment, molding defects such as reduction in dimensional accuracy and generation of burrs and wrinkles, which are caused by the movement of the lower bending mold 73 being hindered by the occurrence of the surplus, are suppressed as much as possible. Can be.

  In the case of pressing metal materials, etc., in general, for the purpose of reducing wrinkles and improving dimensional accuracy, the pressing process is executed in multiple steps step by step, and the amount of deformation caused by a single pressing process is reduced. Set to reduce. Therefore, even in the bending compression process described above, from the separation position to the contact processing position is set as one process, and as another process, from the contact processing position to the pressure processing position, It is natural for those skilled in the art to perform these processes separately. However, if the processing from the separation position to the contact processing position and the processing from the contact processing position to the pressure processing position are performed separately (as non-continuous), the outermost periphery generated by processing to the contact processing position is performed. The deformation of the ring stops. Therefore, in the subsequent processing from the contact processing position to the press-contact processing position, the outermost peripheral ring portion expands and deforms toward the inner side and the outer side in the radial direction, and the outermost peripheral ring is formed by the extension deformation toward the outer side in the radial direction. A surplus portion is produced at the radially outer portion of the portion (front flange portion). In this case, the above-described molding defects occur, and the effects of the present invention cannot be achieved. That is, the present invention does not hold when the processing from the separation position to the contact processing position and the processing from the contact processing position to the press-contact processing position are executed by separate dies. For example, if it is formed into a curved shape by the conventional method of FIG. 7 and then compressed in the front and back direction using another mold, the above-described molding failure occurs.

  According to the bending compression process of the present embodiment described above, the outermost peripheral ring portion 43 is folded back in the radial direction, and the front side surface 43a of the outermost peripheral ring portion 43 and the back side surface 46a of the front side outer peripheral ring portion 46 are formed. It can be accurately and stably formed in a desired form in surface contact. Here, the outermost peripheral ring portion 43 and the front side outer peripheral ring portion 46 can be in a form in which the front side surface 43a and the back side surface 46a are in close contact with each other without any gap. Thereby, since the integrity of the outermost peripheral ring portion 43 and the front side outer peripheral ring portion 46 is increased, the front side flange portion 31 formed from these has high durability against a repeated load generated during the traveling of the automobile. It can be demonstrated.

  After such a bending compression process, an inclined bending process is performed. The inclined bending process is performed by an upper working mold 76 and a lower working mold 78 as shown in FIG. Here, the upper machining die 76 includes an upper inclined machining surface portion 77 having a predetermined inclination angle with respect to the radial direction (radial imaginary plane P) perpendicular to the central axis L. The lower machining die 78 includes a lower inclined machining surface portion 79 that faces the upper inclined machining surface portion 77 of the upper machining die 76. By the upper inclined machining surface portion 77 of the upper machining die 76 and the lower inclined machining surface portion 79 of the lower machining die 78, the outermost circumferential ring portion 43 and the front outer circumferential ring portion 46 which are pressed by the bending compression machining process are formed. Clamp along the front and back direction. As a result, the outermost peripheral ring part 43 and the front side outer peripheral ring part 46 which are in pressure contact are deformed so as to be integrally inclined to the front side. The angle of bending in the inclined bending process is set as the above-described inclination angle θ (see FIG. 2). In this way, the annular surface peripheral portion 32 on the design surface side and the annular back peripheral portion 33 folded back from the annular surface peripheral portion 32 and coupled inward in the radial direction are formed. The annular front peripheral portion 32 and the annular back peripheral portion 33 are integrally formed by being pressed against each other, and are further inclined to the front side.

  After the inclined bending process, a step forming process is performed. The step forming step is performed with an upper support die 81 and a lower working die 83 as shown in FIG. The upper support die 81 includes an upper support surface portion 82 that supports the inclined annular peripheral portion 32 from the front side. The lower working die 83 includes a step portion forming peripheral portion 84 that protrudes upward. In the step forming step, by pressing the step forming peripheral portion 84 of the lower working die 83 while supporting the annular surface peripheral portion 32 by the upper support surface portion 82 of the upper support die 81, An annular groove 37 that is recessed outward is formed. Here, the disc back surface portion 6 is defined as an annular portion located on the back side of the wheel disc 3, inward of the front side flange portion 31 and adjacent to the front side flange portion 31.

  In this way, the front flange portion 31 is formed on the outer peripheral edge portion of the disk-shaped preform 41. And the wheel disk 3 concerning a present Example is shape | molded by this disk shaped preform 41. FIG. The wheel disc 3 and the wheel rim 2 described above are used to obtain the automobile wheel 1 of this embodiment (see FIG. 1). Here, the annular groove portion 37 is formed on the disk rear surface portion 6 of the wheel disc 3 as described above, and the front bead seat portion 13 of the wheel rim 2 is seated in the annular groove portion 37 as described above. The two are welded together (see FIG. 2).

  In the manufacturing method of the present embodiment, the outermost peripheral ring portion 43 bent along the front and back directions is bent inward in the radial direction by the bending compression processing step of the front flange portion forming step described above, and further continuously the plate. Since the pressure contact is made in the thickness direction, it is possible to cause a molding failure due to a surplus in the radially outer portion of the outermost peripheral ring portion 43 (front flange portion 31) during molding. Can be suppressed. Therefore, according to the manufacturing method of the present embodiment, it is possible to accurately and stably form the front flange portion having a desired dimension and shape, and it is possible to stably manufacture a desired automobile wheel as a whole.

  In addition, since the front side flange part shape | molded by this manufacturing method is a structure which an annular front peripheral part and an annular back peripheral part contact | abut, it was equipped with the front side flange part which comprised the conventional curved shape mentioned above. Compared to the configuration, there is an effect that durability against a repeated load generated during traveling of the automobile is improved. More specifically, the curved front flange portion of the conventional configuration is easily deformed repeatedly so that the curved form is expanded or narrowed by a load acting via a tire or an axle during traveling of the automobile. The curved outer periphery easily reaches the fatigue limit. Therefore, in the conventional configuration, the durability life of the front flange portion greatly affects the life of the automobile wheel. On the other hand, the front flange portion according to the present manufacturing method has a configuration in which the annular front peripheral portion and the annular rear peripheral portion are in surface contact with each other. Deformation is unlikely to occur at the coupled portion of the peripheral portion and the annular back peripheral portion. Therefore, as described above, the vehicle wheel manufactured by the manufacturing method of the present invention can exhibit higher durability than the vehicle wheel having the conventional configuration described above.

  In the above-described embodiment, only the lower folding die 73 is moved in the folding compression processing step. However, as another method, only the upper press-contacting die 71 is moved. Alternatively, both the upper pressure contact mold 71 and the lower folding mold 73 may be moved.

  In the case of the above-described embodiment, the annular groove is formed on the back surface of the disk. However, the annular groove may not be formed.

  Further, in the configuration of the above-described embodiment, the welding is performed from the outside of the wheel rim to the wheel circumferential direction. However, the welding may be performed from the inside of the wheel rim to the wheel circumferential direction. .

  In this invention, it is not limited to the Example mentioned above, About another structure, it can change suitably within the range of the meaning of this invention.

DESCRIPTION OF SYMBOLS 1 Automobile wheel 2 Wheel rim 3 Wheel disk 12 Back side flange part 13 Front side bead seat part 13a Open end part 31 Front side flange part 32 Annular surface peripheral part 33 Annular back peripheral part 41 Disc shaped preform 43 Outermost peripheral ring part 46 Front side Outer peripheral ring portion 46a Back side surface 46b (front side outer peripheral ring portion) Front side surface 71 (front side outer peripheral ring portion) Front side surface 71 Upper pressure contact mold 72 Pressure contact surface portion 73 Lower folding die 74 Curved surface portion 75 Turned surface portion

Claims (3)

An automobile having a wheel rim having a rear flange portion formed at one opening edge and a front bead seat portion formed at the other opening edge, and a wheel disc having a front flange portion formed at an outer peripheral edge portion. In the wheel manufacturing method,
A pre-bending process step of bending the outermost peripheral ring portion provided in the disk-shaped preform for forming the wheel disk to the back side along the front and back direction;
By folding the outermost ring part bent toward the back side inward in the radial direction, the outermost ring part is brought into surface contact with the back side surface of the outer peripheral ring part on the front side of the design surface that is coupled to the outermost ring part. A series of bending compression processing steps in which the outermost ring portion and the front outer ring portion are compressed and pressed in the thickness direction;
The annular outer peripheral portion formed by the front outer peripheral annular portion and the outermost peripheral portion are sequentially executed by performing an inclined bending process for inclining the outermost peripheral annular portion and the front outer peripheral annular portion integrally in the front direction. A method for manufacturing a wheel for an automobile, characterized in that a front side flange portion that includes an annular back peripheral portion formed by an annular portion and that is inclined to the front side is formed on an outer peripheral edge portion of a wheel disk. The bending compression process is
An upper pressure contact mold having a pressure contact surface portion that presses in contact with the front side surface of the front side outer peripheral ring portion on the design surface side;
A curved surface portion for folding the outermost peripheral ring portion bent to the back side radially inward, and a folded surface portion that extends radially inward from the curved surface portion and faces the pressure contact surface portion of the upper pressure contact mold. With the lower bending mold provided,
By moving from the separated position that does not pinch the outermost ring part bent to the back side and the front side ring part in a relatively close direction along the front and back direction,
The outermost peripheral ring portion is converted into a contact processing position where the inner peripheral ring portion is folded back in the radial direction so as to follow the curved processing surface portion and the folding processing surface portion of the lower bending mold, and is brought into surface contact with the back side surface of the front outer peripheral ring portion, 2. The automobile according to claim 1, wherein the vehicle further moves continuously and is converted into a pressure welding position where the outermost circumferential ring portion and the front outer circumferential ring portion are compressed and pressed in the plate thickness direction. Wheel. The bending compression process is
3. The method for manufacturing an automobile wheel according to claim 2, wherein the pressure contact position is set so that the compression ratio with respect to the contact position is 80% or more and 95% or less.

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