JPH09267601A - Cast wheel and finishing thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cast wheel which can be made with high productivity and has excellent quality. SOLUTION: This cast wheel 10, where a hub 12 and a rim 20, and a spoke 30 for jointing them are cast, is formed by casting materials of the hub 12 which forms the cast wheel 10, the spoke 30 extending the radial direction from the hub 12, and the rim 20 subjected to plasticity processing. The rim part of a wheel material which forms the cast wheel 10 is an annular material whose wall thickness on the side in the width direction is formed thinner than its central part. This is supported on a die whose shape is contrary to that of a rim inner surface. With this rotating, a rotating dies is pressed against and moved to the side to form a recessed part for fitting a tire.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel of an automobile or a motorcycle, and more particularly to a cast wheel in which a hub and a rim and spokes connecting them are integrally formed by casting, and a finishing method therefor.

[0002]

2. Description of the Related Art Generally, cast wheels have been widely used in many motorcycles in recent years because they have a large degree of freedom in design and do not require a spoke assembling process. However, since the rim of the wheel has a circumferential groove that fits the tire open toward the outer peripheral direction, it cannot be cast with a simple mold with two halves when casting the rim, and it is divided into four or more. Needed a complicated mold to be. In addition, the portion of the rim on which the tire is fitted requires a finished surface with excellent surface roughness to prevent air leakage, so it cannot be a product before casting, and it is forged into the rim of cast wheel material. A finishing method is employed in which a tire fitting surface is formed after processing is performed to densify the structure or cutting processing is performed without performing a forging step.

On the other hand, a hub and a rim are separately formed and are connected to each other by spokes made of steel wire, or a spoke is welded with a disk instead of being assembled. There, the wheel rim is plastically worked. That is, a band steel, which is a raw material, is formed by roll processing, then cut into a predetermined length, and both ends are butt-welded and formed into an annular shape.

[0004]

As described above, in the conventional cast wheel, the rim portion is finished by cutting, so it takes a long time to improve the surface roughness, and in addition, There was a problem that the yield was low and the productivity of the wheels was significantly reduced. Further, since the surface portion which is cast and hardened by cutting is cut off, there is a problem that mechanical strength is lowered. Further, it has been known that the wheel rim is manufactured by plastic working, but in the past, since it was adopted simply for manufacturing convenience, the hub and the spoke and the rim are separately manufactured and assembled by welding or the like. However, in addition to the molding process, an assembling process is required, the manufacturing cost rises, and a structure for connecting a hub and the like is indispensable, so that there is a problem that the degree of freedom in design is limited.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to obtain a wheel having high strength and easy to manufacture. A cast wheel has a hub and a rim, and a spoke connecting them. In a cast wheel integrally formed by casting, the hub wheel forming the cast wheel, the spokes extending in the radial direction from the hub, and the rim material to be plastically worked are molded by casting. Specifically, the base portion connected to the spokes of the wheel material forming the cast wheel, the bead support portion connected to the side thereof, and the ear portion extending from the bead support portion in the outer peripheral direction are formed by plastic working. Further, the manufacturing method is such that a hub and a rim, and a spoke wheel integrally connecting the hub and the rim, are integrally formed by casting a light alloy, and a rim portion of a wheel material forming the cast wheel is wider than a central portion thereof. Directional side is thin annular material, supported by a mold that is the reverse of the inner surface of the rim, rotate this and press the rotary die,
It is finished by moving the rotary die to the side and molding the fitting recess of the tire. Specifically, in a casting wheel in which a hub and a rim, and spokes that connect them are integrally formed by casting of a light alloy, the rim portion of the wheel material forming the casting wheel is located in the width direction side as compared to the center portion. One is a thin annular material on the other side, and this is supported by a mold that is the reverse of the inner surface of the rim, and this is rotated while pressing the rotary die from the outside toward the center, and this is against the material A tire fitting recess is formed by advancing and retracting and compressing the inner diameter of the rim along the mold and expanding it in the width direction. Further, specifically, the processing by the rotary die may be performed by making a notch in the widthwise central portion of the wheel material, and then expanding the notches toward the left and right sides from the notch, and the rotating die is at the center. The part may have a large diameter and a small diameter on both sides to form a substantially abacus bead shape, which may be pressed against a rotating wheel material and rotated to move it laterally.

[0006]

The hub, the spokes, and the rim are integrally formed by casting, and they are connected to each other without any mechanical or metallurgical joining process. The rim portion has a surface roughness that allows the tire to be directly fitted on the rim portion by plastic working, and the material is wrought to improve the mechanical properties. The cast wheel material has a thick rim shape in the central portion and a thin thickness in the widthwise outer side, and can be cast by a relatively simple split-type casting die. Since the rotation of the wheel material is transmitted to the rotating die,
Because the rotating die rotates and is pressed against the wheel material and the contact point between the material and the rotating die changes constantly, and the contact area between the wheel material and the rotating die is small,
The friction between them is small and the wheel material is effectively deformed with a relatively small pressing force.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. In the figure, 10 is a completed cast wheel. The cast wheel 10 has a hub 12 having an axle hole 13 and a diameter of about 450 mm.
It is for motorcycles with the tire fitting groove 21 of the rim 2
0 and the spokes 30 connecting them are integrally formed by metallurgy. In this embodiment, since the configurations of the hub 12 and the spokes 30 are not so different from the conventional ones, detailed description thereof will be omitted.

In the present invention, the tire fitting groove 21 located on the outer surface of the rim 20 is, as shown in FIG. 1 (b),
A base portion 22 connected to the spokes 30 is connected to the center portion in the width direction of the wheel. The base portion 22 is plastically worked to form a dense structure. Also, the base part 2
2 has a substantially U-shaped cross-sectional shape that opens in the outer peripheral direction, and has a highly rigid connection structure with the spokes 30.
A bead support portion 23 for supporting the bead of the tire is continuously provided on the left and right outer sides of the base portion 22 in the width direction. The bead support portion 23 is formed with the reinforcing rib 25 formed between the bead support portion 23 and the base portion 22, and the ear portion 2 extending from the outer end portion to the outer peripheral direction.
It is reinforced from both sides by two ribs 4 and 4, and has a structure that can withstand the strong tension of the tire bead. Rim 20
In addition to this, a central rib 26 located at the center of the base portion 22 on the inner peripheral portion and a side rib 27 integrally formed with the ear portion 24 are formed so as to project toward the centripetal direction. Thus, the rim 20 is formed to have a relatively thin and uniform thickness from the base portion 22 to the side, is made lightweight, and has high rigidity.

Next, the cast wheel 1 having such a structure
0 will be described. The production of the cast wheel 10 starts with the wheel blank 15 shown in FIG. 2, in which an aluminum alloy is cast by gravity casting. Wheel material 15
The rim portion 15a has a thick center portion in the width direction and a thin side portion. Therefore, it is possible to cast by a left-right split mold D shown by a virtual line. The wheel material 15 thus obtained is plastically processed by a spinning machine as described later.

As shown in FIG. 4, the spinning machine is
Like a lathe, it has a bed, a rotating main shaft, and a saddle (both not shown) slidably supported on the bed, and a mold E supported by the main shaft and a spindle 31 are rotatable. The rotary die 32 and the like are supported on the saddle, and the supporting frame 33 that supports these is fixed on the saddle.
The rotary die 32 has a substantially abacus shape with a large diameter in the center and a small diameter in the widthwise outer direction, and the supporting frame 33 supporting the rotating die 32 is axially (left and right in the figure) together with the saddle.
In addition to being able to move to the above, it is controlled by a numerical control device (not shown) to move back and forth toward the axis line CL, and specifically, moves along the contour of the tire fitting groove 21 of the rim 20. It is like this.

In order to process the wheel material 15 with the above apparatus, first, as shown in FIG. At this time, a slight gap C is left in the radial direction between the outer peripheral surface of the mold E and the rim portion 15a of the wheel material 15. Next, the wheel material 15 is rotated at a high speed of 200 to 300 rpm together with the mold E. At this time, the peripheral speed of the rotary die 32 rotates along with the rotation of the wheel material 15 and becomes about 350 m / min. Under this condition, in Figure 4,
As shown by the phantom line, the rotary die 32 is pushed into the widthwise central portion of the rim portion 15a by a pressing force of about 20t, and the material is divided into right and left portions. When this process reaches the end and the rotary die 32 reaches a predetermined depth, the rim portion 15a is pressed against the outer surface of the mold E, and at the same time the gap C disappears,
A part thereof is pushed into the space for the central rib 26 provided in the mold E to form the central rib 26.

When the rotary die 32 has the shape of an abacus or is rotated and is subjected to continuous molding, the contact point between the wheel material 15 and the rotary die 32 constantly changes, and therefore the force required to deform the wheel material 15 is increased. Is less. Further, the small diameter of the rotary die 32 and the small contact area with the wheel material 15 are also effective in reducing friction and facilitating molding. That is, as a result of reducing the friction between them, an effective deformation is given to the wheel material with a small pressing force. In this embodiment, since the heat generated by friction is not so small, lubricating oil or a lubricant is supplied as necessary and pushed into the wheel material 15.

Next, the rotary die 32 is moved outward from the center in the width direction. At this time, the rotary die 32 moves with respect to the surface corresponding to the base portion 22, the bead support portion 23, or the ear portion 24 formed on the mold E, leaving a gap corresponding to the thickness of the rim 20. The wheel material 15 on the side surface of the rotary die 32 is pressed against the outer surface of the mold E, and at the same time, the wheel material 15 is stretched outward while being handled. Thus, one side of the rim 20 is formed. Similarly, the rotary die 32 is moved to the opposite side, and the remaining portion is processed to complete the rim 20. The casting wheel 10 has a rim 2
When 0 is completed, a valve hole is drilled in the rim 20,
At the same time, with the rim 20 as a processing reference, the axle hole 13 and the mounting hole formed in the hub 12 are processed to obtain a finished product.

The rim 20 of the cast wheel 10 thus obtained is processed by the rotary die 32 to have a smooth surface, and the metal structure becomes dense to improve the mechanical properties. Also, because molding is not based on cutting,
In addition to eliminating the need for auxiliary work such as grinding of the cutting tool, chips are not generated during processing and the material yield is improved.

[0015]

As described above, according to the present invention, since the hub, the spokes, and the rim of the cast wheel are joined by casting, an assembling step is not required and the productivity is good.
Further, since the rim finishing process is performed by plastic working, the surface roughness of the product is improved, the wear of the tire is reduced, and cutting waste is not generated, so that the material yield is excellent. Further, there is an effect that a large machine such as a press machine is not required for molding.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, which is a product wheel, (a) is a front view seen from the axle direction, and (b) is a BB sectional view thereof.

FIG. 2 is a cross-sectional view showing a manufacturing process, which is a casting material that is a material of a casting wheel.

FIG. 3 is a cross-sectional view corresponding to FIG. 2 showing a state where a casting material is attached to a mold.

FIG. 4 is a sectional view corresponding to FIG. 3 showing a shape during molding.

FIG. 5 is a side view corresponding to FIG. 3 showing the shape at the end of molding.

[Explanation of symbols]

10 ... Cast wheel 12 ... Hub 13 ... Axle hole 15 ... Wheel material 15a ... Rim part 20 ... Rim 21 ... Tire fitting groove 22 ...・ ・ ・ Base part 23 ・ ・ ・ ・ Bead support part 24 ・ ・ ・ ・ ・ ・ Ear part 25 ・ ・ ・ ・ Reinforcing rib 26 ・ ・ ・ ・ Center rib 27 ・ ・ ・ ・ ・ ・ Side ribs 30 ・ ・ ・ ・ ・ ・ Spokes 31 ・・ ・ ・ Support shaft 32 ・ ・ ・ Rotating die 33 ・ ・ ・ Support frame C ・ ・ ・ ・ Gap D ・ ・ ・ ・ Mold E ・ ・ ・ ・ Mold CL ・ ・ ・ ・ Axis

Claims (6)

[Claims] 1. A casting wheel integrally formed by casting a hub and a rim, and a spoke connecting them, and a hub forming the casting wheel, a spoke extending radially from the hub, and a rim that is plastically worked. Cast wheels made by casting the above material. 2. A cast wheel in which a hub, a rim, and spokes connecting them are integrally formed by casting, and a base portion connected to the spokes of the wheel material forming the cast wheel, and a bead support portion connected to the side thereof. , And a cast wheel formed by plastically forming an ear portion extending from the bead support portion in the outer peripheral direction. 3. A cast wheel in which a hub and a rim, and spokes connecting them are integrally formed by casting of a light alloy, and a rim portion of a wheel material forming the cast wheel is in a width direction side as compared with a central portion. One is a thin annular material, the other one is supported by a mold that is the reverse of the inner surface of the rim, and this is rotated to press the rotary die, and the rotary die is moved to the side to fit the tire fitting recess. A method for finishing a cast wheel for molding. 4. A cast wheel in which a hub and a rim, and spokes connecting them are integrally formed by casting of a light alloy, and a rim portion of a wheel material forming the cast wheel is located in a width direction side as compared with a central portion. One is a thin annular material on the other side, and this is supported by a mold that is the reverse of the inner surface of the rim, and this is rotated while pressing the rotary die from the outside toward the center, and this is against the material A finishing method for a cast wheel in which the inner diameter of a rim is advanced and retracted to compress it along the mold and then expanded in the width direction to form a fitting recess for a tire. 5. The processing according to claim 3 or 4, wherein the rotary die is machined into a notch at a widthwise central portion of the wheel material, and the notch is expanded laterally from there. Finishing method for casting wheels to be molded. 6. The wheel material rotating according to claim 3 or 4, wherein the rotary die has a substantially abacus bead shape in which a central portion has a large diameter and both sides have small diameters. Finishing method for casting wheels, which is performed by pressing against and rotating to move laterally.