JP2006102869A - Wheel, its machining method and machining device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a machining device and a machining method of a light alloy wheel free to produce a wheel favorable in precision even in mass production and to provide the light alloy wheel from a bead seat part of which deflection is especially reduced by them. <P>SOLUTION: The wheel molded of a material by casting a wheel diameter of which is more than 16 inches and the deflection of the bead seat part of which is less than 0.2 mm is manufactured by machining an offset surface of the wheel material, fixing the offset surface of this wheel material on the machining device as a machining standard part and lathe-machining an outer peripheral surface of its rear rim part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wheel machining apparatus and a machining method capable of reducing the flare to a limit when lathing a rim portion by casting a light alloy wheel for a vehicle, and is manufactured by the same. It is related to a wheel with a small flare.

  There are various materials and structures of automobile road wheels, but for the purpose of reducing the weight and improving the appearance and design of automobiles, the ratio of mounting light alloy wheels such as aluminum wheels is increasing. . This light alloy wheel is generally manufactured by a low pressure casting method. This is because, in the low pressure casting method, the molten metal is filled into the mold cavity at a low speed, so that gas entrainment and oxide generation are suppressed as much as possible as compared with other casting methods.

  In general, a light alloy wheel 30 has a thick hub attachment portion 31 attached to an axle by bolts and nuts as shown in FIG. 9, and a disc portion 32 composed of spokes 33 having a mixture of thick and thin portions. And a thin rim portion 34 to which the tire is attached. The shape of the rim is strictly defined by the standard. The outer flange 35 and the inner flange 36, and the outer side bead sheet 37 and the inner side bead sheet 38 have a shape for contacting the tire and sealing the air inside, and are particularly important parts. The disk portion 32 is formed with a through hole 39 (hub hole) for connecting to the vehicle. The back side of the hub mounting portion is processed into a flat surface (offset surface 40) and fixed to the hub of the vehicle.

  Conventionally, when these wheels are manufactured and processed by low pressure casting, first, a wheel material for a vehicle is cast by a low pressure casting machine. Next, a portion where the hub hole of the disk portion of the wheel material is formed is drilled. Thereafter, the wheel material is subjected to heat treatment such as T6 treatment. The heat-treated wheel material is processed in the order shown in FIG. First, the outer flange is held and fixed by a clamp, and the entire end surface of the outer flange is fixed to a chuck device of a lathe machine as a processing reference portion. Then, the outer peripheral surface and the inner peripheral surface including the bead seat portion on the inner flange side of the rim portion are cut. Thereafter, the inner flange having the final shape is held and fixed by a clamp, and the outer peripheral surface including the bead sheet portion of the rim portion on the outer flange side is turned. At this time, if necessary, the surface of the spoke part and the disk surface are processed. The step of drilling the hub hole or the bolt hole is provided between any of the above steps. As a result, it is processed into a final product shape, which is painted and baked to become the final product.

  As the trend of light alloy wheels in recent years, the increase in diameter is conspicuous. This is because there is no difference in weight between the small-diameter wheel and the steel wheel, but the effect of weight reduction appears in proportion to the increase in diameter, and functions such as improved fuel economy when mounted on a vehicle. Because it does. However, a vehicle wheel, which is an important safety part, is required to have a dimensional accuracy equivalent to that of a small diameter even if the diameter is increased. The standards that are basically the standards of vehicle manufacturers are (1) rim cylindricity and roundness, (2) wheel balance (flare), and (3) strength. The strength of (3) can often be dealt with by design matters such as thickening the wheel.

  Patent Document 1 (Japanese Patent Laid-Open No. 9-66410) discloses a finger chuck structure used in lathe machining as a suitable method for improving the machining accuracy related to (1) and (2). In this publication, the existence of a clamp seat and a centering member is disclosed, and when turning a light alloy wheel, the rotation axis of the processing machine and the axis center of the wheel are clamped without deviating, and a device capable of high-precision processing is disclosed. It is made. However, the technique represented by Patent Document 1 is considered on the assumption that the wheel is a perfect circle and the rim end surface is a flat surface. In fact, cast light alloy wheels are distorted and deformed even in the disk part when heat treatment and cooling are performed after casting. Therefore, the warped rim end is pressed against a flat surface and clamped, the chuck device and the wheel are not centered and fixed, and precise machining accuracy cannot be obtained. Each company has tried to reduce distortion by inserting a disk-shaped jig on the inner surface of the rim of each wheel during heat treatment, but it can be improved under the constraints of simplifying the line and shortening the cycle time. That is practically difficult.

  Patent Document 2 (Japanese Patent Application Laid-Open No. 2002-144804) describes a vibration prevention device for a tire wheel holding chuck that includes an anti-vibration damper that supports an inner rim end. The processing standard in this processing apparatus is substantially the inner diameter of the hub hole. At first glance, unlike Patent Document 1, the roundness centered on the rotation axis is high, and it seems that it is easy to process a wheel that does not run out. It is fixed and drilled to the processing equipment as the processing standard. Therefore, in the same manner as described in Patent Document 1, the rim end which is distorted is pressed against a flat surface and is clamped. In this state, the chuck device and the wheel are not centered and fixed, and in a strict sense, the hub hole is not drilled coaxially with the intended rotation axis. Although the stopper 6 is positioned in the chuck axis direction on the offset surface of the wheel, the wheel is fixed by a chuck body for fixing the hub hole and a vibration damping damper at the rim end. The chuck body is simply fixed so as to expand concentrically from the inner peripheral surface of the hub hole, and the rim end is pushed to the outer side by a vibration-proof damper. The stopper 6 is not substantially pressed against the offset surface and is simply in contact with or slightly floating. The details of the structure of the stopper 6 are not described in Patent Document 2, and the effect of the stopper 6 is described only as a positioning means in the chuck axis direction. Even if the wheel is rotated in this state and the bead seat portion of the rim is turned, the runout can be machined with a certain degree of accuracy, and mass production cannot be performed with a runout accuracy of 0.2 mm or less. .

Further, in Patent Document 3 (Japanese Patent Laid-Open No. 5-228701), as a processing device with small deflection and short processing time, the hub hole is fixed from the inner side and the rim end is installed on the inner side which can be fixed by a buffer member. And a processing device including a tailstock that elastically supports the wheel by pressing the hub hole of the wheel from the disk surface side. However, Patent Document 3 does not describe the details of the role of the collet holder in contact with the offset surface, and in the structure of Patent Document 3, the wheel hub hole is pushed from the disk surface side to elastically support the wheel on the fixing device. Since the tailstock is configured to be large, the entire processing device becomes large, causing problems in production, and when the wheel is attached to the processing device, it is necessary to move the tailstock to a different place once and every time. This configuration is difficult to shorten.
Japanese Patent Laid-Open No. 9-66410 ((0016) to (0017), FIG. 2) JP 2002-144804 ((0009) to (0013), FIG. 1) JP-A-5-228701 ((0020) to (0023), FIG. 1)

  Therefore, the present invention provides a light alloy wheel processing apparatus and processing method capable of mass production of a wheel with much higher accuracy than the prior art in order to solve the above-mentioned problem, and in particular, thereby reducing the bead sheet flare. To provide a light alloy wheel.

Since the processing accuracy of the wheel required by the vehicle manufacturer is determined by the rim portion (bead seat portion) when it is assembled to the vehicle, the processing conditions are the same as the processing conditions. Focusing on the fact that the reference portion is an offset surface fixed to an actual vehicle hub is a means for solving the problems of the present application. The offset surface is fixed perpendicular to the turning axis of the lathe machine, and the rotation axis is determined by the hub hole so that it is fixed to the lathe machine in the same state as that mounted on the vehicle, and then cut by the vehicle manufacturer. Can manufacture the high-precision products required.
That is, the present invention is characterized in that an offset surface of a wheel material is processed, the offset surface of the wheel material is fixed to a processing apparatus as a processing reference portion, and then the outer peripheral surface of the rim portion is turned. Further, the hub hole may be used as a processing reference portion at the same time. The hub hole is preferably chucked by means capable of being fixed from the inner flange side through the inside of the rim portion, and the offset surface of the wheel material is attracted to the processing device, and then the outer peripheral surface of the rim portion is lathe processed.

  In the present invention, the processing reference portion refers to a contact portion that substantially fixes the wheel material to the processing machine. A portion that abuts using an elastic body such as a buffer member does not indicate a processing reference portion. In order to increase the dimensional accuracy, it is desirable that the dimensional error of the processing reference portion is small. The processing reference portion may be processed after the heat treatment, or may be processed before the heat treatment subjected to thermal deformation. By processing the portion that becomes the processing reference after the heat treatment at the time of the F material having no distortion before the heat treatment, it is possible to manufacture a wheel with no further dimensional error. Further, the offset surface is a contact surface formed on the rear side of the disk portion of the wheel and in contact with the hub when the vehicle hub is connected with a bolt or the like. Normally, this offset surface is continuously flattened when turning the inner peripheral surface of the rim. The hub hole in the present invention refers to a hole for a rotating shaft formed on a disk surface for connection with a vehicle body and a hole for caulking with a bolt formed around the hole.

  At the time of lathe processing, it is preferable to fix each portion of the wheel distorted by heat treatment to the processing machine without using it as a processing reference portion. The hub located at the center of the disk is not easily affected by heat treatment. A wheel with very little deflection can be manufactured by machining a hub hole in the disk portion to form a processing reference portion, fixing the wheel material to the processing machine at this processing reference portion, and turning. As described above, since the entire rim is turned by clamping the rim end face which has been distorted in the past, it has been difficult to process with high accuracy. If the hub hole is processed with high accuracy before the heat treatment, a processing reference portion that is far more accurate than the distorted rim after the heat treatment can be obtained. Conventionally, the hub hole may be drilled before heat treatment to exclude solidified pieces from the gate. However, this is merely for removing the molten solidified piece from the product gate in the center gate method where this is the mold gate. The hub holes obtained by conventional processing do not take into account dimensional accuracy such as surface roughness and inner diameter. The final finishing of the hub hole is performed by lathe processing after heat treatment. Naturally, the hub hole is processed with high accuracy before heat treatment, and the idea of using the processing reference portion after heat treatment is not made at all. Of course, the accuracy of the hub hole may be obtained not only by drilling but also by lathe processing.

  As described above, it is difficult to obtain the dimensional accuracy of the light alloy wheel targeted by the present invention even if the hub hole is formed after the heat treatment and the processing reference portion is formed. This is because the rim portion is deformed by heat treatment, so that even if any of the flanges is fixed, the rim portion is displaced from the chuck device, and the processing axis of the hub hole by the drill or lathe is displaced from the rotational axis of the wheel. It is possible to perform processing while reducing the influence of distortion at the time of heat treatment by processing a portion where distortion is unlikely to occur at the time of F material with small distortion and using the processed portion as a processing reference portion after heat treatment.

  A vertical lathe can be used for processing the hub. In the case of a large diameter, a vertical lathe is more advantageous in view of mechanical rigidity. When the hub hole is machined with a roundness of 1.0 mm or less and a concentricity with the wheel material of 0.5 mm or less, it is easier to obtain a target light alloy wheel with less deflection and distortion. The roundness is preferably 0.3 mm, more preferably within 0.1 mm, and the preferred concentricity is 0.1 mm, further within 0.05 mm. The diameter of the hub hole is about φ50 to 65 mm. Concentricity is for a datum shape with the rim of the wheel material taken as a perfect circle.

  Further, the processing device of the present invention is a processing device for lathing the rim portion of the wheel, the offset surface abutment portion for fixing the offset surface of the wheel perpendicular to the lathe rotation axis, And a fixing portion for fixing the disk surface to the processing apparatus from the inner flange side through the inside of the rim portion. This processing apparatus preferably includes a buffer member that contacts the inner flange. Further, it is preferable to use a chuck device that can hold and grip the inner peripheral surface of the hub hole and pull it toward the inner flange side. As a result, it is possible to obtain a wheel formed by casting in which the wheel diameter is 16 inches or more and the flare of the bead sheet portion on the inner side is 0.2 mm or less in mass production.

  FIG. 1 shows a process flow of the present invention. First, a wheel material is cast (step 1), and an offset surface is formed by machining (step 2). Thereafter, the offset surface is fixed to the chuck device as a processing reference portion. An example of the chuck device is shown in FIGS. The chuck device 10 is freely rotatable with respect to a chuck device main body (not shown). The chuck device 10 is provided with an arm for fixing a hub hole of a wheel material on a back plate 11 along a rotation axis. This arm mainly consists of a pedestal 12, a collet holder 13, a collet 14, and a fixed plate 15 having an offset surface. The pedestal 12 is fixed on the back plate 11 with bolts. A collet holder 13 is bolted on the pedestal 12, and an offset surface fixing plate 15 is concentrically fixed to the top of the collet holder 13. The collet holder 13 has a cylindrical shape, and the fixing plate 15 has a disk shape with a hole formed in the center. The collet 14 is assembled so as to slide in the collet holder 13. An elastic member 16 is provided between the collet 14 and the base 12, and the collet 14 slides within the collet holder by a predetermined distance. Although the collet 14 is substantially cylindrical, a plurality of slits are provided on the tip side. When the wide-angle member 17 is pushed into the collet, the tip side of the collet 14 opens and grips the inner peripheral surface of the hub hole of the wheel material. be able to. A rod 18 is provided on the wide-angle member 17, and this rod 18 extends to the back plate 11 along the center of the collet 14 and the axis of rotation of the base 12, and is slidably driven within the back plate 11. A buffer member 19 is provided on the outer peripheral side of the back plate 11. The buffer member 19 includes a coil having a predetermined spring coefficient and a piston for buffering the flange portion during processing. The buffer member 19 is provided so as to push the inner flange in the axial direction from the inner side, and has a role of suppressing the wobbling of the wheel material flange portion during lathe processing.

  A state where the wheel material is fixed to the chuck device will be described. As shown in FIG. 5, in a state before the wheel material is fixed, the rod 8 moves to the tip side, and the wide-angle member 17 does not push the collet 14 apart. At this time, the outer diameter of the collet 14 is smaller than the inner diameter of the hub hole of the wheel material. The wheel blank 30 is arranged coaxially with the chuck device by a robot arm (not shown), and is pushed into the chuck device side as shown in FIG. First, the buffer member 19 comes into contact with the inner flange and compresses the coil in the piston. In this state, the wheel material is pushed in until the offset surface 40 contacts the fixed plate 15. With the axial position of the wheel material determined in this way, the rod 18 is pulled into the processing apparatus main body, and the wide-angle member 17 at the tip pushes the tip side of the collet 14 apart. In a state where the tip side of the collet 14 grips the inner peripheral surface of the wheel material hub hole, the rod 18 is further given a pulling force toward the processing apparatus main body, and the offset surface 40 of the wheel material is pressed against the fixed plate 15 to Make the offset plane perpendicular to it. This fixed state is very close to the state mounted on the vehicle hub (step 3). In this state, the outer peripheral surface (bead sheet portion) of the rim is processed (step 4).

Further, it is preferable that a part of the processing is performed before the heat treatment to form a processing reference portion in the lathe processing after the heat treatment. The reason will be described below.
The cylindricity and roundness of the rim part deteriorate in dimensional accuracy when heat treatment is performed. The thickness of the rim itself is very thin, and is about 10 mm for the wheel material before turning. The required material thickness is the same for both small and large calibers. If the diameter is small, there is no problem. However, if the diameter is increased, the thickness is reduced with respect to the diameter of the cylindrical rim portion, so that deformation is likely to occur. It has been confirmed that the deformation of the rim portion mainly occurs during heat treatment and subsequent quenching (water quenching). Even if a large amount of cast heat-treated products are to be quenched together, it is difficult to uniformly cool the rim portion of each wheel material in the circumferential direction, and it is considered that the rim portion is distorted due to this. Conventionally, the rim end face of the wheel material after heat treatment is turned using the machining reference part, but this rim end face is deformed and distorted by the heat treatment, and even if this rim end face is clamped to the processing machine as the machining reference part. Strictly speaking, since it is fixed and turned in a bent state, it tends to be out of the target dimensional error range. There is also a processing method as described in Patent Document 2 in which the hub hole is a processing reference portion, but the processing reference portion that is fixed to the machining apparatus when the hub hole is drilled is the rim end surface as described above. Therefore, the hub hole itself is drilled while being coaxial or inclined with respect to the rotation axis of the wheel. After all, the hub hole is fixed and turned while the balance of the wheel is lost even if the hub hole is used as the machining reference part. Easy to come off.

  In particular, the rim portion of the wheel material immediately after casting manufactured by casting is not a perfect circle, and the thickness of the rim varies in the circumferential direction. Looking at the thickness of the rim in the circumferential direction, the thickness of the rim is relatively thick on the horizontal dividing surface. In contrast, the horizontal central portion is thin. That is, the rim thickness changes in order of thick, thin, and thick every 90 °. As shown in FIG. 10, in order to release the horizontal mold of the casting machine without galling from the wheel, the cavity on the mold crack surface forming the outer periphery of the rim is provided with a draft gradient with respect to the moving direction of the horizontal mold. This is because. As a result, the rim molded with the cracked surface is about 2 to 4 mm in the center gate bill and about 8 to 12 mm in the side gate bill or multi-gate bill in which the rim is provided as compared with the rim molded in the center portion of the horizontal mold. It is thick. If heat treatment is performed with this thickness difference remaining, the amount of thermal deformation at the thick and thin portions changes, which is the main factor that distorts the rim. Therefore, it is an effective means for suppressing distortion to process the rim portion so as to have a uniform thickness in the circumferential direction by turning the rim portion once before heat treatment.

  The above method is preferably applied to a side gate method in which a gate for forming a rim portion is provided with a gate and a multi-gate method in which a gate is provided for each of a disk portion and a rim portion. In these bills, the solidified pieces at the gate remain on the peripheral surface of the rim. Therefore, as described above, the rim wall thickness varies more than the center gate method that supplies molten metal from the disk portion. In particular, since the multi-gate bill is an optimum bill for manufacturing a large-diameter wheel, the effect of applying the present invention is much greater in the strain suppression work that must be taken into consideration in the manufacture of the large-diameter wheel.

  The processing for making the thickness uniform is preferably performed while leaving a uniform processing allowance within 0.05 mm to 3 mm with respect to the product target dimension. When it is less than 0.05 mm, when some distortion occurs due to other factors, there is a possibility that the machining allowance is insufficient when machining to the final target dimension. However, processing within the final target dimension, that is, 0.05 mm before heat treatment is also within the scope of the present invention. Further, the processing for making the thickness uniform is preferably performed on both the inner peripheral side and the outer peripheral side of the rim. However, the processing is not particularly limited to this, and the processing may be performed only on the inner peripheral surface or the outer peripheral surface.

  The composition of the alloy to be cast is known, for example, AC4C, AC4CH materials used for aluminum wheel applications, Al-Si-Cu, Al-Si-Mg, Al-Mg alloys, etc. , ADC5 material, ADC10 material, ADC12 material, etc. can be used as appropriate. Furthermore, although the present invention exerts a more advantageous effect on the manufacture of wheels of 16 inches or more, the effect itself is the same and is not limited by the size even with a smaller wheel. Although some of these methods of the present invention have been described, it is a matter of course that further effects can be obtained by measuring the distortion of the wheel in consideration of using a plurality of methods in combination. Even with a wheel of 16 inches or more, it is possible to manufacture a light alloy wheel having a flare of 0.20 mm or less and 0.10 mm or less on the inner and outer bead sheet portions.

As described above, the rim portion (bead sheet portion) has been conventionally lathe processed with the rim end or hub hole as the processing reference portion, but according to the present invention, the offset surface of the wheel material is used as the processing reference portion, Since the wheel material is turned in a state closest to the state of being fixed to the vehicle, the wheel dimensional error required by the vehicle manufacturer is extremely small, and a vehicle wheel with higher safety can be provided.
Further, by subjecting the wheel material to a predetermined processing before the heat treatment and using or using the processed portion as a processing reference portion after the heat treatment, a vehicle wheel with smaller dimensional error can be provided.
In addition, by processing at least a part of the rim portion so that the wall thickness is uniform along the circumferential direction before heat treatment, the distortion of the rim portion due to heat treatment is eliminated more than before, and a vehicle with higher accuracy. Wheel can be provided.
By applying these manufacturing methods of the present invention, even a light alloy wheel having a large diameter of 16 inches or more has a flare at the bead seat portion within 0.20 mm, and further within 0.10 mm. Succeeded in manufacturing stably.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited by these Examples.

Example 1
A detailed example of the process flow of the present invention is shown in FIG. First, the light alloy wheel used was an integrally cast wheel that was low-pressure cast. In low-pressure casting, AC4C material or the like was used as a raw material for the molten metal, and the mold used was a multi-gate method in which a pouring gate was provided around the center position of the disk part of the wheel and around the rim part. As a result, a wheel material (F material) in which the rim portion and the disc portion are integrated was obtained (Step 1). A hub hole having a diameter of 53 mm was formed by lathe processing at the center position of the disk portion of the F material. However, a machining allowance of 1.5 mm is left for the final hub hole dimension (56 mm). The bolt holes in the disk part were formed in the same manner. In processing the hub hole, a processing machine LAW-V24 manufactured by Okuma Corporation was used, and the feed rate in the axial direction was set to 5 mm / s. As a result, the inner surface of the hub hole could be machined with a roundness of 0.2 mm or less and a concentricity of 0.03 mm defined as the final product dimensions (STEP 1a). Thereafter, the wheel material in which the hub hole was processed was heat-treated at 545 ° C. × 4.0 h and then water-cooled, and then T6 treatment was performed (140 ° C. × 2.0 h) (STEP 1b). This heat treatment caused distortion on the disk surface. The strain was measured by bringing the outer flange of the wheel into contact with a flat surface and measuring the gap generated between the outer flange and the flat surface with a gap gauge. The number of samples is 30. The generation of gaps due to this was an average of 0.55 mm for 17-inch wheels and an average of 0.61 mm for 18-inch wheels.

The wheel material after the heat treatment was processed using the hub hole as a processing reference portion. The collet chuck, which is an inner diameter reference jig, was mounted on the lathe machine chuck device from the outer flange side (step 1c). In addition, the axial position is adjusted so that the end of the outer flange is in contact with the buffer member from the axial direction, and at the same time, occurrence of deflection during lathe machining is suppressed. The lathe processing conditions were 1600 revolutions and a bite feed rate per revolution of 0.8 to 1.2 mm. In this state, the offset surface, which is the fixed surface of the hub, was turned (step 2).
Thereafter, the wheel material was removed from the collet chuck, and the wheel material was fixed using the offset surface and the hub hole as a processing reference portion using the chuck device of the present invention shown in FIGS. 5 and 6 (step 3). In addition, the inner flange was brought into contact with the buffer member to suppress the occurrence of wobbling. The lathe processing conditions were 1600 revolutions and a bite feed rate per revolution of 0.8 to 1.2 mm. In this state, the outer peripheral surface of the rim was turned from the outer flange to the inner flange (step 4).
Thereafter, the wheel material is removed from the chuck device of the present invention, the wheel material is turned over again, and the outer flange is fixed by a conventional chuck device as shown in FIG. 7, and the inner flange end portion and the inner peripheral surface side of the rim portion are fixed. A lathe was processed (step 4a). In addition, with the outer flange as a processing reference portion, the hub hole and the bolt hole were finally processed to obtain a wheel processed product having a final product shape. The variation of the outer diameter of the vehicle wheel with respect to the rotation axis was measured. The test rotating shaft was fixed to the hub hole, and the error (flare) with respect to the target dimension was measured by rotating the wheel while bringing the surface roughness meter needle into contact with the outer peripheral surfaces of the inner and outer bead sheets. The measurement positions were 10 equiangular positions (every 36 °). Table 1 shows the maximum value of the flare with respect to the target dimensions of the inner side and outer side bead sheets of the present invention, and the standard deviation thereof.

(Comparative Example 1)
A comparative experiment was performed in the conventional process as shown in FIG. After manufacturing the F material in the same manner as in Example 1, only a simple drilling process for removing the sprue of the hub hole was performed, and a heat treatment was immediately performed. As shown in FIG. 7, the heat-treated wheel material was first pressed against a jig for fitting the end face of the outer flange against a flat surface or an F material shape. Thereafter, it was held and fixed by a clamp, and the inner flange surface and outer periphery surface on the inner flange side were cut by fixing the outer flange material shape to a chuck device of a lathe machine using the processing shape as a processing reference. Thereafter, hub holes and bolt holes were drilled, and then the inner flange side, which was the final shape, was held and fixed with a clamp, and the outer flange, disk surface, and hub hole were turned. Table 1 shows the maximum flare value and its standard deviation in the inner and outer bead sheets of Comparative Example 1.

(Example 2)
An example of the flow of another process of the present invention is shown in FIG. First, the light alloy wheel used was an integrally cast wheel that was low-pressure cast. In low-pressure casting, AC4C material or the like was used as a raw material for the molten metal, and the mold used was a multi-gate method in which a pouring gate was provided around the center position of the disk part of the wheel and around the rim part. As a result, a wheel material in which the rim portion and the disc portion are integrated is obtained (Step 1). This wheel material was heat-treated at 545 ° C. × 4.0 h, then water-cooled, and then T6 treatment was performed (140 ° C. × 2.0 h) (STEP 1a). The distortion of the disk surface by this heat treatment was the same as in Example 1.
The outer flange of the wheel material was fixed to the conventional chuck device shown in FIG. 7 (Step 1b). The wheel material is rotated with the outer flange as a processing reference, and the cutting tool is moved to move the inner rim side surface, the inner peripheral surface of the rim (step 1c), the spoke back portion, and the offset surface (step 2). Lathes were processed into a predetermined shape in this order. The processing conditions for lathe processing are the same as in the first embodiment. The dimensional error on the inner peripheral surface side of the rim was processed within 0.3 mm.
Thereafter, drilling of the hub hole and the bolt hole was performed (STEP 2a).
Next, the wheel material was fixed to the wheel material using the chuck device of the present invention shown in FIGS. 5 and 6 using the offset surface and the hub hole as a processing reference (step 3). In addition, the inner flange was brought into contact with the buffer member to suppress the occurrence of wobbling. In this state, the outer peripheral surface of the rim was turned from the outer flange to the inner flange (step 4) to obtain a wheel processed product having a final product shape.
The variation of the outer diameter of the vehicle wheel with respect to the rotation axis was measured. The test rotating shaft was fixed to the hub hole, and the error (flare) with respect to the target dimension was measured by rotating the wheel while bringing the surface roughness meter needle into contact with the outer peripheral surfaces of the inner and outer bead sheets. The measurement positions were 10 equiangular positions (every 36 °). Table 1 shows the maximum value of the flare with respect to the target dimensions of the inner side and outer side bead sheets of the present invention, and the standard deviation thereof.

(Example 3)
Another embodiment of the present invention will be described in detail with reference to the flowchart of FIG. The light alloy wheel was a 17-inch diameter integrally cast wheel that was low-pressure cast. The AC4C material was used as a molten material in low-pressure casting, and the mold used was a multi-gate method in which a pouring gate was provided around the center position of the disc portion of the wheel and around the rim portion. As a result, a wheel material (F material) in which the rim portion and the disc portion are integrated was obtained (Step 1). The thickness of the central part of the rim of the F material was measured at the horizontal mold crack surface during casting and the horizontal central part in the 90-degree direction. On the horizontal mold crack surface, a solidified piece of the molten metal remained at the position where it was the pouring gate, and the horizontal was measured as the maximum thickness. The thickness of the rim at this portion was 8 mm, and the thickness of the rim at the horizontal central portion was 16 mm including the spout burr.
Thereafter, the outer flange of the F material was fixed to the chuck device. Lathe machining was performed so as to leave a machining allowance of 1.5 mm for both the outer and inner diameters of the final target dimensions. Further, the hub hole was processed in the same manner as in Example 1. The thickness error in the rim circumferential direction of the lathe processed portion was within 0.3 mm (Step 1a). This processed F material was subjected to the same T6 treatment as in Example 1 (STEP 1b).

The wheel material after the heat treatment was turned in the same manner as in Example 2. The outer flange of the wheel material was fixed to the conventional chuck device shown in FIG. 7 (Step 1c). The wheel material is rotated with the outer flange as a processing reference, and the cutting tool is moved to move the inner rim side surface, the inner peripheral surface of the rim (step 1d), the spoke portion back side, and the offset surface (step 2). Lathes were processed into a predetermined shape in this order. The dimensional error on the inner peripheral surface side of the rim was processed within 0.3 mm.
Then, the hub hole and the bolt hole were drilled (step 2a).
Next, the wheel material was fixed to the wheel material using the chuck device of the present invention shown in FIGS. 5 and 6 using the offset surface and the hub hole as a processing reference (step 3). In addition, the inner flange was brought into contact with the buffer member to suppress the occurrence of wobbling. In this state, the outer peripheral surface of the rim was turned from the outer flange to the inner flange (step 4) to obtain a wheel processed product having a final product shape.
The variation of the outer diameter of the vehicle wheel with respect to the rotation axis was measured. The test rotating shaft was fixed to the hub hole, and the error (flare) with respect to the target dimension was measured by rotating the wheel while bringing the surface roughness meter needle into contact with the outer peripheral surfaces of the inner and outer bead sheets. The measurement positions were 10 equiangular positions (every 36 °). Table 1 shows the maximum value of the flare with respect to the target dimensions of the inner side and outer side bead sheets of the present invention, and the standard deviation thereof.

It is a flowchart which shows the manufacturing process of this invention. It is a flowchart which shows the detailed manufacturing process of this invention. It is a flowchart which shows the detailed manufacturing process of this invention. It is a flowchart which shows the detailed manufacturing process of this invention. It is an example of the chuck device of the present invention. It is an example of the chuck device of the present invention. It is a figure which shows an example of the conventional chuck | zipper apparatus. It is a flowchart which shows the conventional manufacturing process. It is sectional drawing of the wheel for vehicles. It is a figure which shows a horizontal type | mold omission gradient position.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Horizontal type, 10 Chuck apparatus, 11 Back plate, 12 Base, 13 Collet holder, 14 Collet, 15 Offset surface fixing plate, 16 Elastic body, 17 Wide angle member, 18 Rod, 19 Buffer member, 30 Vehicle wheel, 31 Hub, 32 Disc part, 33 spoke, 34 Rim part, 35 Outer flange, 36 Inner flange, 37 Outer side bead sheet, 38 Inner side bead sheet, 39 Hub hole, 40 Offset surface

Claims (7)

A wheel machining method comprising machining an offset surface of a wheel material, fixing the offset surface of the wheel material to a machining apparatus as a machining reference portion, and then lathing the outer peripheral surface of the rim portion. The hub material and the offset surface of the wheel material are machined, and the wheel material is fixed to the machining apparatus so that the inner circumferential surface and the offset surface of the hub hole are perpendicular to the lathe turning axis, and then the rim part is fixed. A method of processing a wheel, characterized by lathing the outer peripheral surface of the wheel. The hub hole and offset surface of the wheel material are machined, and this offset surface is fixed to the machining device as a machining reference portion. At the same time, the hub hole is chucked from the inner flange side through the rim portion, and the wheel material offset surface is machined. A method of processing a wheel, characterized in that the outer peripheral surface of the rim portion is then lathe-worked. A processing device for lathe machining of a wheel rim part, an offset surface abutting part for fixing an offset surface of a wheel perpendicular to a lathe rotation axis, and an inner flange side through a rim part And a fixing portion for fixing the disk surface to the processing device. The processing apparatus according to claim 1, wherein the processing apparatus includes a buffer member that contacts the inner flange. The processing device according to claim 1, wherein the fixing portion uses a chuck device that pushes and grips the inner peripheral surface of the hub hole and can be pulled into the inner flange side. A wheel characterized by being formed of a material by casting having a wheel diameter of 16 inches or more and a bead sheet flare of 0.2 mm or less.

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