JPH05162004A - Cutting of disc wheel for automobile - Google Patents

Abstract

PURPOSE:To prevent a rim from swinging in a vertical direction at the time of cutting the rim, carry out finishing with high dimension accuracy, and make the axial core of the rim meet a hub hole. CONSTITUTION:The surface rim 8 of a molding integrated disk wheel 1 is chucked, and the bead seat part 16' of a back rim 9 is cut with a prescribed finishing edge left. The back rim 9 of the disk wheel 1 is chucked, and the bead seat part 16 of the surface rim 8 is cut with a prescribed edge left. The hub hole 4 of the disk wheel 1 is cut. The back surface of the disk part 22 of the disk wheel 1 is placed on a surface plate to center the disk wheel 1 with a clamp shaft which is engaged with the hub hole 4, a chock absorber is made to come into light contact with the flange edge surface of the back rim 9, and the bead seat parts 16, 16' of the surface and back rim 8, 9 are finished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cutting an automobile disc wheel.

[0002]

2. Description of the Related Art Conventionally, when cutting a disc wheel for an automobile, a bead seat portion and a hub hole of a rim on which a tire is mounted are usually cut by chucking a rim flange. And the hub hole are not necessarily processed in the same process, and the bead seat portion of the rim is chucked on the front rim and the bead seat of the back rim is also disclosed in, for example, Japanese Patent Laid-Open No. 2-36001. The parts were cut by a lathe, and then the back rim was chucked, and the bead seat part of the front rim was also cut.

[0003]

However, as described above, in the conventional cutting method, it is difficult to exactly match the hub hole and the rim axis with each other, and when the disc wheel is mounted on the automobile, the rim becomes vertically long. There was a problem of swinging and uncomfortable riding. When the disk wheel rotates about the hub hole as an axis, the vertical runout causes the tire mounting portion of the rim to swing in the radial direction and eccentrically rotate, and the causes thereof are as follows. (1) Accuracy of the lathe (2) Chucking method (3) Deformation of the workpiece itself during chucking (1) is determined by the lathe itself, but regarding (2), how to take the core during hub hole machining If the method of taking the core during rim processing is the same, the accuracy will improve. However, normally, it is extremely difficult to perform all the processing such as the bead sheet portion of the front and back rims and the drilling processing by one-time chucking. Therefore, the processing is divided into several steps as described above. Therefore, since chucking must be performed again between the steps, the axial center of the hub hole and the axial center of the rim do not coincide with each other, which causes vertical shake. With regard to (3), since a certain force is always required for chucking, the work is slightly deformed by the chucking force. Therefore, if the chucking is removed after processing, the work returns to its original state. This slight deformation causes vertical shake.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to perform a finishing process with high dimensional accuracy without causing the rim to vertically swing during the cutting process of the rim. And a method of cutting a disc wheel for an automobile, in which the axis of the rim is aligned with the hub hole.

[0005]

In order to achieve the above object, the present invention comprises the steps of chucking the front rim of a cast integrated disc wheel and cutting the bead seat portion of the back rim while leaving a predetermined finishing allowance. A step of chucking the back rim of the disc wheel and cutting the bead seat portion of the front rim with a predetermined finishing allowance; a step of cutting a hub hole of the disc wheel; and a disc of the disc wheel. Place the backside of the part on the surface plate, center the disc wheel with the clamp shaft that fits in the hub hole, and lightly abut the shock absorber on the end face of the back rim. It is configured by cutting the sheet portion and fitting it to a predetermined dimensional accuracy.

[0006]

In the present invention, the clamp shaft is fitted into the hub hole to center the disc wheel, thereby aligning the hub hole with the center axes of the bead seat portions of the front and back rims. If the bead seats of the front and back rims are finished with the rim free, the rim receives the force of the bite, and so-called chattering occurs, making normal processing impossible.
Therefore, if the shock absorber is lightly pressed against the end surface of the rim, chatter of the rim can be reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for cutting an automobile disk wheel according to the present invention will be described below in detail with reference to the drawings. First,
Explaining the structure of the disc wheel, the disc wheel 1 is made of a casting made of a metal such as aluminum or magnesium, and is formed into a cylindrical body having an open rear side as shown in FIG. The disk portion 22 is integrally provided with a cylindrical rim 3 that is provided so as to protrude toward the outer periphery of the back surface. The entire surface of the disc portion 22 forms a design surface, a hub hole 4 is formed at the center thereof, and a plurality of bolt holes 5 and an opening portion 6 for design or weight reduction are provided around the hub hole 4. One valve hole 7 is formed. The hub hole 4 is fitted to the axle (axle) and serves as the center of rotation of the disc wheel 1.
High dimensional accuracy is required. The rim 3 has a built-in braking device inside and tires mounted on the outer peripheral surface. From the appearance, the rim 3 is further referred to as a front rim 8 and a back rim 9. Further, both ends of the front rim 8 and the back rim 9 are bent outward in the radial direction to form a front flange 2 and a back flange 2 ', respectively, thereby forming a shallow bottom rim (or a deep bottom rim). ing. The bead seat portions 16 and 16 ′ on which the tires of the front rim 8 and the back rim 9 are mounted have high dimensional accuracy because the inner opening edge portions of the tires are in close contact with each other, and the above-mentioned hub is used to reduce vertical runout of the rim 3. It is required to match the axis of the hole 4.

Next, a cutting process of the disc wheel 1 having the above-mentioned structure will be described.

(1) Cutting process of the bead seat portion of the back rim The front end face of the front flange 2 of the cast integrated disc wheel 1 is brought into contact with the surface plate 11 of the NC lathe chuck to make the front flange 2
Is chucked by the chuck 12. When chucking, select any part with high dimensional accuracy of the wheel and perform accurate centering. Thereafter, the bead seat portion 16 'of the back rim 9 is cut by the cutting tool 13 while leaving a predetermined finishing allowance. As an example of the cutting conditions, in the case of a disc wheel having a rim diameter of 16 inches and a rim width of 7 inches, the rim rotation speed is 1000 r.p.m. p. m ~ 1200
r. p. m, tool feed: 0.2 mm / time, stock removal:
It was 0.5 mm. The finishing allowance is from 0.2 mm
It is about 0.3 mm.

(2) Bolt Hole Machining Step The bolt hole 5 of the disc wheel 1 machined by the above-mentioned steps is machined by the drill 14 shown in FIG. 2 to obtain a predetermined dimensional accuracy. At this time, of course, the valve hole 7 may be cut at the same time. This drilling is usually performed by a machining center, but it may be performed by a drilling machine.

(3) Cutting process of bead seat of front rim As shown in FIG. 3, the disc wheel 1 which has undergone the process of (2) above has the opening end face of the rim 3, that is, the end face 15 of the back rim 9 as shown in FIG. The back rim 9 is chucked against the surface plate surface 11 of the chuck by the chuck 12, and the bead sheet portion 16 is cut by the cutting tool 13 while leaving a predetermined finishing allowance. Cutting conditions and finishing allowance are exactly the same as those of the back rim 9 described above.

(4) Hub hole machining step The hub hole 4 is usually machined as described in (1) Back rim machining, or
(3) At the same time as processing the front rim, drill 30 as shown in FIG.
By cutting and finish to the specified dimensional accuracy.

(5) Finishing process for the bead seats of the front and back rims. The disc wheel 1 which has undergone the above process is removed from the NC lathe, and the back face of the disc part 22 is placed on the surface plate 17 of the vertical lathe chuck shown in FIG. 18 is set, the clamp shaft 20 is fitted into the hub hole 4, and the disc wheel 1 is centered. Further, the shock absorber 31 is lightly brought into contact with the end surface 15 of the back flange 2'of the disc wheel 1, and then, in this state, the bead seat portions 16 and 16 'of the front rim 8 and the back rim 9 are brought into contact.
With a cutting tool 13, cutting only the finishing allowance (0.2 mm to 0.3 mm) left in the steps (1) and (3),
The disc wheel 1 as the final product is obtained. The shock absorber 31 is composed of, for example, a pusher element that can be moved back and forth and a spring that urges the pusher element. By urging the end surface 15 of the back flange 2 ′ in the axial direction of the disc wheel 1, the shock absorber 31 is rimed during cutting. Prevent chatter in 3. It has been found by various experiments that the biasing position of the shock absorber 31 in this case is not limited to the above-mentioned position and may be any position as long as it is the back flange 2'or its vicinity and does not interfere with the cutting process. There is. The reason why such an effect is brought about is not clear yet, but it is considered that the biased shock absorber 31 suppresses the resonance of the rim. Further, when the clamp shaft 20 is fitted in the hub hole 4 to perform centering and chucking of the disc wheel 1, it is possible to reduce deformation of the wheel itself due to chucking as compared with the conventional chucking method. As a result, accurate finishing can be performed, and the axis of the bead seat portions 16 and 16 'of the front rim 8 and the back rim 9 can be aligned with the axis of the hub hole 4. The pressing force of the shock absorber 31 may be large, but if it is about 100 gr, a sufficient chattering prevention effect can be obtained.

(6) Appearance inspection and measurement of dimensional accuracy The disc wheel 1 obtained through the above steps is used as a platen 17
Then, the visual inspection and the vertical runout of the bead seat portions 16 and 16 'of the hub hole 4, the front rim 8 and the back rim 9 are measured, respectively, and the manufacturing of the disc wheel 1 is completed.

When the measurement was performed on 19 disc wheels, the results shown in the following table were obtained.

[0016]

[Table 1]

As for the vertical runout of the bead seat portions 16 and 16 'of the front rim 8 and the back rim 9, the maximum and minimum values when the disc wheel is rotated once are measured with a dial gauge, and the difference is taken as the vertical runout. It is displayed. Ave is the difference between the maximum and minimum values of the entire circumference of the average value obtained by adding the vertical runouts of the front rim 8 and the back rim 9 and dividing by 2, X is the average value of all the disc wheels, and σ is the standard Deviation and CPU are process capability values. The larger the value of CPU, the better, and it is expressed by the following equation.

[0018]

[Equation 1] However, SU is the upper limit of the standard.

Here, comparing the conventional cutting method described above with the method of the present invention, in the conventional method, Ave = 0.
Although 07 mm and CPU = 0.48, Ave = 0.04 mm and CPU = 1.540 could be set in the method of the present invention. This means that the hub hole 4
This means that the axis of the rim 3 is well aligned with the axis of the rim 3, and the vertical vibration of the rim is small, and it is possible to improve the vibration of the automobile, in other words, to improve the riding comfort.

[0020]

As described above, in the method for cutting a disk wheel for an automobile according to the present invention, the disk shaft is centered by fitting the clamp shaft into the hub hole, and the flange end surface of the back rim is shocked. Lightly pressed with an absorber, and in this state, the bead seat part of the front and back rims is finished, so there is little vertical runout of the rim,
The bead seats of the front and back rims can be processed with high precision, and the axis of the rim can be aligned with the axis of the hub hole.

[Brief description of drawings]

FIG. 1 is a diagram showing a cutting process of a bead seat portion of a back rim in a cutting method for an automobile disc wheel according to the present invention.

FIG. 2 is a diagram showing a bolt hole processing step.

FIG. 3 is a diagram showing a cutting process of a bead seat portion of a front rim.

FIG. 4 is a diagram showing a hub hole processing step.

FIG. 5 is a diagram showing a finishing process of the bead sheet portions of the front and back rims.

[Explanation of symbols]

 1 Automotive Disc Wheel 2 Front Flange 2'Back Flange 3 Rim 4 Hub Hole 5 Bolt Hole 6 Opening 7 Valve Hole 8 Front Rim 9 Back Rim 16, 16 'Bead Seat 21 End Edge of Back Rim 22 Disc Part 31 Shock Absorber

Claims (1)

[Claims] 1. A step of chucking a front rim of a cast integrated disc wheel and cutting a bead seat portion of the back rim with a predetermined finishing allowance, and a step of chucking the back rim of the disc wheel to remove the front rim. A step of cutting the bead seat portion of the disk wheel leaving a predetermined finishing allowance, a step of cutting a hub hole of the disc wheel, and a disk part back surface of the disc wheel is set on a surface plate to form the hub hole. The center of the disc wheel is centered by the fitting clamp shaft, the shock absorber is lightly abutted on the back rim end face, and in this state, the bead seats of the front and back rims are cut and processed to the specified dimensional accuracy. A method of cutting a disc wheel for an automobile, comprising the steps of: