JP4130786B2 - Manufacturing method of steel wheel disc for automobile - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a steel wheel disk for automobiles, and more particularly to a hole punching process for forming heat radiation holes.
[0002]
[Prior art]
It is well known that a two-piece full design wheel has been proposed as a steel wheel for automobiles, which has a wider design area viewed from the front side (design side) and has improved design. Such a two-piece full design wheel is composed of a steel wheel disc having a flange portion formed on the outer peripheral portion and a rim having a rim flange portion, etc., and the flange portion of the steel wheel disc is fitted to the inner peripheral surface of the rim. In general, a welded structure is used.
[0003]
The steel wheel disc of such a two-piece full-design wheel will be described in further detail. The steel wheel disc usually includes a hub attachment portion having a hub hole formed in the center, and a disc main plate portion is formed on the periphery of the hub attachment portion. ing. The disk main plate portion is gently inclined toward the front side (design surface side) as it goes outward from the center (hub hole). In other words, it has a dish shape with the center (hub hole) as the bottom. Further, the disk main plate portion is provided with a plurality of heat radiation holes in the circumferential direction around the hub hole. And the spoke part which protruded with respect to the inner periphery of a heat radiation hole is formed between each heat radiation hole. Further, a flange portion substantially parallel to the wheel axial direction is formed on the outermost peripheral edge of the disk main plate portion.
[0004]
When this steel wheel disc is fitted to the rim, the entire surface of the disc main plate becomes a design surface, so that a wide design area can be secured.
[0005]
Here, the steel wheel disc of the two-piece full-design wheel is characterized in that, as described above, a spoke portion that is raised by a predetermined height with respect to the formation surface of the heat radiation hole is disposed between the heat radiation holes. In this respect, it is greatly different from a general-purpose steel wheel disc in which the heat radiation holes are formed on the same circumferential surface and the spoke portion is not formed.
[0006]
The steel wheel disc of the two-piece full design wheel described so far can be obtained by the following manufacturing method.
First, a disc-shaped steel plate is punched to intermittently form a plurality of arc-shaped notches on the periphery of the steel plate. At the same time, the steel plate is drawn by a predetermined die using a press machine or the like. By this drawing process, the steel plate is formed into a dish shape with the hub hole as a bottom. And the part used as a spoke part is curved in the radial direction or a tangential direction among the inclined surfaces of this shape | molded steel plate, and the said part is raised. As a result, the raised portions are formed radially around the hub hole. Thereafter, each recess formed between the radially formed raised portions is subjected to punching using a cam-type drilling die or the like. Thereby, a spoke part and a thermal radiation hole are obtained.
[0007]
By the way, this cam type punching die converts a vertical operation of a press machine into a predetermined inclination angle operation corresponding to the bottom surface of the recess. As a result, the punch and die for punching can be made to act substantially perpendicularly to the inclined concave bottom surface. Here, the heat radiation hole is formed on the bottom surface of the recess by using the cam type punching die in this manner, the generation of burrs caused by the slip on the bottom surface of the recess, the punch for punching This is to prevent damage to the parts.
[0008]
Finally, the outermost peripheral edge of the steel plate is bent so as to be substantially parallel to the wheel axial direction to form a flange portion, thereby obtaining a desired steel wheel disk (see, for example, Patent Document 1). ).
[0009]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-2201
[Problems to be solved by the invention]
However, when the dish-shaped steel plate is bent as described above and the spoke portion is raised, a so-called plate shrinkage may occur in the spoke portion. This board shrinkage appears more prominently as the spokes are raised significantly with respect to the adjacent parts in order to improve the design. Such plate shrinkage causes the thickness of the spoke portions to be non-uniform and reduces the strength of the entire wheel disc. Moreover, as shown in FIG. 10, since the plate-drawing line b is generated on the surface of the spoke part a so as to be visible, the design property is also lowered. Therefore, in the manufacturing method of the conventional configuration, the spoke part must be formed to such an extent that no plate shrinkage occurs, and a wheel disk in which the spoke part is dynamically raised cannot be manufactured. was there.
[0011]
Further, the above-described hole punching using a cam-type hole punching mold has problems such as a complicated mold structure and a shortened service life of the hole punching part. Furthermore, as shown in FIG. 10, since the cut section c formed at the periphery of the heat radiation hole is visible from the front side when mounted on the vehicle body, there is a problem that the appearance is deteriorated. Furthermore, if the recesses between the spoke parts are punched from above, the angle between the punched cross section of the heat radiation hole and the back surface of the disk main plate part becomes an acute angle (so-called sharp edge). There is also a problem that cracks are likely to be generated from the part. As a result, the steel wheel disc had to be made thicker in order to meet the life test.
[0012]
Therefore, an object of the present invention is to propose a method for manufacturing a steel wheel disk for automobiles that can solve these problems.
[0013]
[Means for Solving the Problems]
The present invention includes a peripheral edge of a hub mounting portion having a hub hole formed in the center thereof, a disk main plate portion formed on the peripheral edge of the hub attachment portion, and a wheel axial direction substantially formed on the outermost peripheral edge of the disk main plate portion. A plurality of heat radiating holes provided in the circumferential direction with the hub hole as a center, and an inner peripheral edge of the heat radiating hole disposed between the heat radiating holes. In the manufacturing method of the steel wheel disc for automobiles,
A punching process for forming a plurality of heat radiation base holes as heat radiation holes in the circumferential direction around the hub hole reference point on a steel plate having a square hub base hole serving as a hub hole reference point in the center;
After positioning and inserting the location pin into the hub base hole, the steel plate is bent to raise the space between the heat radiation base holes with respect to the inner periphery of the heat radiation base hole, An intermediate drawing process to obtain a disk-shaped steel plate with a spoke portion formed thereon;
By pressing the disk-shaped steel plate with a float die, adjusting the dimensional accuracy of the shape of the steel wheel disk for automobiles, obtaining the heat radiation hole and the spoke part that protrudes against the inner periphery of the heat radiation hole, and by punching And a final processing step of forming a hub hole . A method for manufacturing a steel wheel disk for an automobile.
[0014]
The present invention is characterized in that the punching process for obtaining the heat radiation hole is performed before the bending process for obtaining the spoke portion. That is, by performing hole punching on a flat plate, for example, there is no need to deflect the working direction of a punch and a die for punching, and thus a structure such as a mold for performing hole punching is conventionally used. It can be simplified compared to the configuration. Further, since the punching load at the time of processing is reduced as compared with the conventional configuration, the fatigue life of parts such as a punch for punching is improved. Therefore, the cost for maintenance is suppressed and the cost of the punching process for forming the thermal radiation base hole can be reduced. Accordingly, it is possible to reduce the manufacturing cost of the steel wheel disc for automobiles as a whole.
[0015]
Here, in the molding process of obtaining the spoke portion by bending, the portion to be bent is adjacent to the heat radiation base hole formed in the punching process. This means that during bending, the tensile stress acting on the part to be bent is diffused by the adjacent heat radiation base hole expanding along with the tensile stress, and the thickness of the part is curved while remaining almost uniform. There is an advantage that it is molded. Therefore, it is possible to prevent the occurrence of local plate shrinkage in the spoke portion. Needless to say, a plate closing line generated due to the plate closing is not detected in the spoke portion of the steel wheel disc for automobile manufactured by such a manufacturing method.
[0016]
Further, in the hole punching process for forming the heat radiation base hole, a configuration is proposed in which the heat radiation base hole is formed in the steel plate so that the hole punching section is perpendicular to the plate surface. .
[0017]
By setting it as this structure, the condition setting at the time of a process is simplified compared with the structure which perforates the inclined plate | board surface. Further, it is possible to prevent the angle between the punched section and the back surface of the disk main plate portion from becoming an acute angle (so-called sharp edge), and to prevent the occurrence of cracks. Furthermore, in such a configuration, the punched cross section that was initially perpendicular to the steel plate surface faces the back side of the disk main plate portion after the molding process, along with the bending process for forming the spoke portion. (See FIG. 8). Thereby, when the steel wheel disk for automobiles is viewed from the front side (design surface side), the holed cross section is hidden behind the disk main plate part and cannot be visually recognized, so that the appearance is improved.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a longitudinal sectional view of a steel wheel A for automobiles. This steel wheel A for automobiles comprises a rim 1 on which tires (not shown) are mounted and a steel wheel disk 2 for automobiles in which a hub hole 3 to which an axle is connected is formed at the center. A flange portion 5 formed on the outer peripheral edge of 2 is fitted into the inner peripheral surface of the rim 1 and integrated. The rim 1 and the automobile steel wheel disc 2 are joined by fillet welding or spot welding. As the fillet welding, arc welding, laser welding, or the like is well known.
[0019]
Next, the steel wheel disc 2 for automobiles will be described in detail with reference to FIGS.
A hub hole flange portion 4 is formed on the peripheral edge of the hub hole 3 so as to rise substantially perpendicularly to the front side (design surface side). Further, five bolt holes 6 are formed at equal intervals in the circumferential direction on the peripheral edge of the hub hole flange portion 4. The hub mounting portion 10 is configured by the hub hole 3, the hub hole flange portion 4, and the bolt hole 6.
[0020]
A disk main plate portion 15 including a heat radiation hole 9 and a spoke portion 11 is formed on the periphery of the hub attachment portion 10. The disk main plate portion 15 is gradually inclined toward the front side (design surface side) as it goes outward from the center (hub hole 3). In other words, it has a dish shape with the center (hub hole 3) as the bottom.
[0021]
Further, five substantially trapezoidal heat radiation holes 9 with corners are formed in the circumferential direction around the hub hole 3. Similar to the bolt holes 6, the heat radiation holes 9 are also provided at equal intervals.
[0022]
Further, a spoke portion 11 is formed between the heat radiation holes 9 so as to be raised with respect to the inner peripheral edge of the heat radiation hole 9. Five spokes 11 are formed radially with the hub hole 3 as the center. Therefore, the heat radiation holes 9 are respectively formed on the bottom surfaces of the recesses between the spoke portions 11. The reasons for forming the heat radiation holes 9 include improvement in design, improvement in rigidity, weight reduction, improvement in heat dissipation, and the like. Moreover, as a reason for raising the spoke part 11 with respect to the inner peripheral edge of the heat radiation hole 9, there are an improvement in design and an improvement in rigidity.
[0023]
In the present embodiment example, a groove having a very shallow bottom is formed along the radial direction at the top of the spoke portion 11 in order to further improve the design.
[0024]
Note that the number of the bolt holes 6, the heat radiation holes 9, or the spoke portions 11 described above may vary depending on the type of automobile or the required design.
[0025]
Further, a flange portion 5 that is substantially parallel to the wheel axial direction is formed on the outermost peripheral edge of the disk main plate portion 15. When the flange portion 5 is fitted into the inner peripheral surface of the rim 1 and welded, the automobile steel wheel A is integrated.
[0026]
Next, the manufacturing method of the steel wheel disk 2 for motor vehicles concerning the principal part of this invention is demonstrated according to FIGS.
First, in order to obtain a steel plate 20B as shown in FIG. 3, as shown in FIG. 4, a disk-shaped steel plate 20A whose center is set as the hub hole reference point 21 is punched. Thereby, the steel plate 20B in which the thermal radiation base hole 9a etc. were formed as shown in FIG. 3 is obtained.
[0027]
More specifically, in the punching process for performing the punching process, the heat radiation punch 30 is vertically operated so that the punching section 25 is perpendicular to the plate surface of the steel plate 20A. Then, as shown in FIG. 3, a rectangular hub base hole 26 is formed at the hub hole reference point 21, and the five heat radiation base holes 9a are evenly distributed in the circumferential direction around the hub hole reference point 21. Form at intervals. Further, five arc-shaped notches 22 are intermittently formed on the periphery of the steel plate B. The notch 22 has a shape cut inward from the outer edge by a predetermined width, and the outer peripheral edge 23 located between the notches 22 later becomes the flange 5.
[0028]
By the way, the planar shape of the heat radiation base hole 9a at the time of punching is substantially trapezoidal with a corner as shown in FIG. 3, but in the present invention, the punching process is executed. Later, in order to execute a forming process for bending the steel plate 20B, the planar shape of the heat radiation base hole 9a changes after the forming process. Therefore, in this hole punching process, the deformation process is estimated in advance by simulation, and the hole is punched in a shape that becomes a desired final planar shape after the bending process.
[0029]
In the present invention, since the hole punching process is configured to perform hole punching in the vertical direction with respect to the uniform plate material, the die of the press machine or the like is not complicated, and the heat radiation hole The lifetime of punching parts such as the punching punch 30 is not shortened. Moreover, since the punching load is small, defects such as burrs are less likely to occur.
[0030]
In the hole punching process described above, five bolt base holes 6a (see FIG. 5) to be the bolt holes 6 may be formed in the circumferential direction around the hub hole reference point 21.
[0031]
Next, a forming process of bending the punched steel plate 20B is executed (see FIGS. 5 to 7).
This molding process mainly includes drawing by a press machine. Here, the molding process is constituted by first to third drawing processes. It should be noted that the pressure load direction (vertical direction) for drawing by a press machine is substantially parallel to the wheel axis direction. This will be described in detail below.
[0032]
First, the first drawing process is executed.
As shown in FIG. 5 (a), the steel base plate 20B in which the heat radiation base hole 9a, the hub base hole 26, and the bolt base hole 6a are already formed is inserted into the location pin 34 protruding upward, and the hub base hole 26 is inserted. And place on the annular drawing die 31 and the seat block 36. The seat block 36 is disposed at the center of the aperture die 31. Then, from above the steel plate 20B, an annular flange pressing block 32 is pressed, and the steel plate 20B is clamped in cooperation with the drawing die 31.
[0033]
Then, as shown in FIG. 5 (b), the drawing punch 33 disposed at the center of the eaves pressing block 32 is pressed against the steel plate 20 </ b> B supported by the seat block 36. At the same time, the aperture punch 33 and the seating surface block 36 are integrally moved to the lowest position. And the steel plate 20B is curved by this, and the saucer-like steel plate 20C is obtained. The seat surface block 36 applies a force to press the steel plate B against the drawing punch 33 from below, and the drawing punch 33 descends against this upward force, so that the seating surface block 36 and the drawing surface block 36 are drawn. The punch 33 is integrally moved to the lowest position.
[0034]
Next, a second drawing process is performed.
As shown in FIG. 6 (a), the tray-shaped steel plate 20C formed in the first drawing process is positioned by inserting the hub base hole 26 into the location pin 34 and set in the press machine. 6 (b), the upper disk mold 40 is press-molded with the location pin 34 as a guide and the tray-shaped steel plate 20C is pressed to form a disk-shaped steel plate 20D having a desired shape. In the second drawing process, the tray-shaped steel plate 20C is inclined upward as it goes outward with the hub base hole 26 as the center, and the adjacent portion of the heat radiation base hole 9a is raised. In other words, the tray-shaped steel plate 20C is formed so that the heat radiation base hole 9a is positioned on the bottom surface of the recess, and the raised portion is formed radially with the hub base hole 26 as the center.
[0035]
Next, a third drawing process is performed.
As shown in FIG. 7A, the disk-shaped steel plate 20 </ b> D formed in the second drawing process is set along the die of the drawing punch 61. Then, as shown in FIG. 7 (b), the steel plate 20D is pressed by the float die 60 and the drawing punch 61 to adjust the dimensional accuracy of the shape of the steel wheel disk 2 for automobiles. And the spoke part 11 which protrudes with respect to the inner periphery of the thermal radiation hole 9 is obtained.
[0036]
Further, as shown in FIG. 7 (b), the outer peripheral edge of the outer peripheral edge of the disc-shaped steel plate 20D where the notch 22 is not formed by the flange diaphragm ring 62 disposed at the outermost position. 23 is bent downward to form a flange portion 5 that is substantially parallel to the wheel axial direction. At the same time, the peripheral edge of the hub base hole 26 is bent upward by the hub hole drawing punch 63 so as to be substantially parallel to the wheel axial direction to form the hub hole flange portion 4.
[0037]
Thereafter, surface finishing such as buffing is applied to the design surface and the like. The steel wheel disc 2 for automobiles is manufactured by the manufacturing method including such a series of steps.
[0038]
By the way, no plate shrinkage occurs in the spoke portion 11 of the steel wheel disk 2 for automobiles manufactured by the above-described manufacturing method. This is because when the bending process is performed to form the spoke portion 11, the pre-formed thermal radiation base hole 9a expands with the tensile stress due to the tensile stress acting on the part to be processed. This is because the material is diffused by the above-described method, and is curved and formed while the thickness of the portion to be processed is substantially uniform.
[0039]
Here, the spoke portion 11 of the steel wheel disc 2 for an automobile according to the present invention (see FIG. 8 (a)) and the spoke portion of the steel wheel disc according to the conventional manufacturing method in which the heat radiation hole is formed after being bent. a (see FIG. 8B) is compared.
[0040]
As shown in FIG. 8 (b), in the conventional configuration, the plate is contracted at the convex apex portion x of the curved spoke portion, and the thickness of the top portion is thinner than the thickness around the heat radiation hole. As a whole, the thickness is uneven. On the other hand, as shown in FIG. 8 (a), in the configuration according to the present invention, the thickness of the top portion of the curved spoke portion 11 is equal to that of the other portions, and is uniformly formed. Therefore, the steel wheel disk for automobiles manufactured by the manufacturing method of the present invention does not have a non-uniform thickness and does not decrease in strength. Will not be damaged.
[0041]
Further, in the automobile steel wheel disc 2 manufactured by the manufacturing method of the present invention described above, as shown in FIG. 9, the punched section 25 faces the back side of the disk main plate portion 15 around the heat radiation hole 9. It is out. This is due to the bending process for forming the spoke portion 11 and the like, and the punched section 25 which was initially perpendicular to the plate surface of the steel plate 20A is as described above along with the bending process. Will be biased. Thus, when the automobile steel wheel disc 2 is mounted on the vehicle body and viewed from the front side (design surface side) in such a state, the holed cross section 25 is hidden behind the disc main plate portion 15 and cannot be seen. Therefore, it has an excellent advantage of improving the appearance.
[0042]
Further, the manufacturing method of the present invention is different from the configuration in which the bottom surface of the recess is punched from above as in the conventional configuration, and is configured to punch the plate material from above, so It is possible to prevent the angle with the lower surface (back surface) of the disk main plate portion 15 from becoming an acute angle (sharp edge). Thereby, generation | occurrence | production of the crack from this site | part can be prevented.
[0043]
【The invention's effect】
The present invention provides a punching process in which a steel plate having a hub hole reference point is punched to form a plurality of heat radiation base holes, and the steel plate after the punching is curved to process each heat radiation. between Motoana, is raised relative to the heat radiating base hole periphery because has a structure that includes a molding step of obtaining a heat radiation holes and the spoke portion, the hole punching can be performed with respect to the flat plate It becomes possible, and it becomes unnecessary to use, for example, a cam-type drilling die or the like as in the prior art, and the structure of a die or the like for performing punching can be simplified. Therefore, the maintenance can be facilitated and the equipment cost can be reduced, and the overall effect of reducing the manufacturing cost of the steel wheel disk for automobile can be obtained. Further, in the molding process, there is an advantage that the thickness of the spoke part after the bending can be made substantially uniform by expanding the preliminarily formed heat radiation base hole along with the bending. As a result, it is possible to prevent the spoke portion from being damaged, and the thickness of the spoke portion is not uniform and the strength is not lowered. Of course, since the plate closing line does not occur, the design of the steel wheel disc for automobiles is not impaired.
[0044]
Also, in the hole punching process for forming the heat radiation base hole, when the steel plate is punched so that the hole punching section is perpendicular to the flat plate surface , the hole punching process is executed. In doing so, there is an advantage that the setting of conditions for punching is simplified. Further, the punched cross section is deflected along with the bending process in the molding process, and after the molding process, it faces the back side of the disk main plate portion around the heat radiation hole. As a result, when the steel wheel disc for automobiles mounted on the vehicle body is viewed from the front side, the punched cross section is hidden behind the disk main plate portion and becomes invisible, so the appearance when mounting the vehicle body is dramatically improved. It becomes possible. In addition, according to such a configuration, since the hole cross section does not become a so-called sharp edge, there is an effect that it is possible to eliminate the generation of cracks at the periphery of the heat radiation hole. Accordingly, it is not necessary to thicken the periphery of the heat radiation hole in order to correspond to the life test, so that the weight of the steel wheel disk for automobiles can be reduced, and the manufacturing cost can be reduced as a whole.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a steel wheel A for automobiles.
FIG. 2 is a front view of a steel wheel disc 2 for an automobile.
FIG. 3 is a front view of a steel plate 20B in which a thermal radiation base hole 9a is formed.
FIG. 4 is an explanatory view showing a hole punching process according to a hole punching process.
FIG. 5 is a process diagram showing a first drawing process.
FIG. 6 is a process diagram showing a second drawing process.
FIG. 7 is a process diagram showing a third drawing process.
8A is a longitudinal side view of the spoke portion 11 according to the present invention cut in a tangential direction, and FIG. 8B is a longitudinal side view of the spoke portion according to the conventional configuration.
FIG. 9 is a longitudinal sectional view of a steel wheel disc 2 for an automobile according to the present invention in which no plate closing line is generated.
FIG. 10 is a longitudinal sectional view of an automotive steel wheel disc having a conventional configuration in which a plate closing line b is generated.
[Explanation of symbols]
2 Steel wheel disc for automobile 3 Hub hole 5 Flange portion 9 Heat radiation hole 9a Heat radiation base hole 10 Hub mounting portion 11 Spoke portion 15 Disc main plate portion 20A to 20C Steel plate 21 Hub hole reference point 25 Hole cross section

Claims (1)

A hub mounting portion peripheral edge formed with a hub hole in the center;
A disc main plate formed on the periphery of the hub mounting portion;
A flange portion formed on the outermost peripheral edge of the disk main plate portion and substantially parallel to the wheel axial direction;
The disk main plate portion is composed of a plurality of heat radiation holes provided in the circumferential direction around the hub hole, and a spoke portion disposed between the heat radiation holes and raised with respect to the inner periphery of the heat radiation hole. In the manufacturing method of a steel wheel disc for automobiles,
A punching process for forming a plurality of heat radiation base holes as heat radiation holes in the circumferential direction around the hub hole reference point on a steel plate having a square hub base hole serving as a hub hole reference point in the center;
First, a location pin is inserted and positioned in the hub base hole, and then curved so that the planar shape of each heat radiation base hole changes, and the steel plate is bent to obtain a tray-shaped steel plate. Drawing process;
After the location pin is inserted and positioned in the hub base hole, the steel plate is bent so that the planar shape of each heat radiation base hole is changed, and heat is generated between the heat radiation base holes. A second drawing step for obtaining a disk-shaped steel plate in which a heat radiation hole and a spoke portion are formed;
By pressing the disk-shaped steel plate with a float die, adjusting the dimensional accuracy of the shape of the steel wheel disk for automobiles, obtaining the heat radiation hole and the spoke part that protrudes against the inner periphery of the heat radiation hole, and by punching And a third drawing step for forming a hub hole.

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