JPH10180400A - Wheel disc, production and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lighten the weight and to reduce the cost while keeping the durable strength for requiring on a parts collected with stress by non-uniformly making the wall thickness even in the circumferential direction of a disc and making the wall thickness of the stress collecting parts thicker in comparison with the other parts. SOLUTION: This wheel disc 10 is produced by swinging a swinging punch 21 and forming projecting and recessing parts 22 on a plurality of numbers of places in the circumferential direction. In this wheel disc 10, the wall thickness is changed in the circumferential direction, by increasing the wall thickness only at the stress concentrated part, the durable strength can be improved. The production device 20 is provided with the swinging punch 21 and a swinging mechanism having two eccentric rollers to swing the swinging punch 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel disk, a method of manufacturing the same, and an apparatus for manufacturing the same.

[0002]

2. Description of the Related Art As shown in FIG. 8, a wheel includes an annular rim 2 (a part for holding a tire) and a disc-shaped disc 1.
(A part for attaching the wheel to the vehicle). Conventionally, as shown in FIG. 7, discs for large wheels such as buses and trucks are obtained by press-punching a circular blank material 4 from a flat plate material 3 and forming the disc shape by drawing with a press machine 5 to form a hub hole 6 and a decorative window. 7 was punched by a press, and the nut seat 8 was prepared by dishing with a multidrill. As shown in FIG. 8, a disk formed by drawing from a flat plate is formed to have a substantially radially uniform cross section. In addition, a wheel disc has been proposed in which the thickness is gradually reduced from the hub mounting portion toward the end (radially outer peripheral end) by cold spinning, but a change in the thickness of the wheel due to spinning has been reported. It was limited to the disk radial direction only, and could not change the plate thickness in the circumferential direction. On the other hand, a decorative window is provided between a portion where the disk is mounted on the vehicle and a portion where the disk is mounted on the rim, and a bolt hole for mounting a wheel is formed in the mounting portion. The window has the function of cooling the brake system located inside the wheel when the wheel is mounted on the vehicle. Wheels mounted on vehicles are required to withstand the repeated load applied from the vehicle mounting part and tires and be lighter in weight. (Hence the product weight) has been affected.

[0003]

Despite the fact that the durability of the wheel is governed by the stress distribution determined by the wheel shape and the disk thickness distribution, it is possible to produce a drawn disk which is restricted by the material shape and processing method. In order to machine a decorative window for obtaining a predetermined cooling effect or to machine a bolt hole conforming to the vehicle specifications, it is not possible to design a decorative window or other low fatigue life site at a place where the generated stress is the lowest. Therefore, in order to guarantee the durability of the wheel, measures are taken by increasing the thickness of the material itself, using a high-grade material having high strength, and strengthening the entire wheel. As a result, unnecessary parts in terms of wheel durability are strengthened, which hinders weight reduction and cost reduction. An object of the present invention is to provide a wheel disk in which only necessary parts such as high stress generating parts are reinforced, a method of manufacturing the same, and a manufacturing apparatus thereof.

[0004]

The present invention to achieve the above object is as follows. (1) A wheel disc manufactured by forming a plate, which has an uneven thickness distribution in the circumferential direction of the wheel disc, and the thickness of the stress-concentrated portion in the circumferential direction is smaller than the thickness of the portion where the stress is not concentrated. A wheel disc that is considered larger. (2) A method of forming a wheel disk having a non-uniform thickness distribution in the circumferential direction of the wheel disk by rocking forging. A method of manufacturing a wheel disk, wherein a plurality of portions are formed in a circumferential direction of a punch, and a wheel disk is formed while swinging the swinging punch. (3) The method according to (2), wherein the swing of the swing punch is a chrysanthemum motion. (4) An apparatus for manufacturing a wheel disc having a non-uniform thickness distribution in the circumferential direction of the wheel disc, wherein a plurality of uneven portions for changing the thickness of the wheel disc are formed in the circumferential direction of the swinging punch. A wheel disc comprising: a swinging punch; a facing type of the swinging punch; and a swinging mechanism coupled to the swinging punch and having at least one motor and at least one eccentric rotor for swinging the swinging punch. Manufacturing equipment.

[0005] In the wheel disk of the above (1), the plate thickness is not uniform even in the circumferential direction of the disk, and the plate thickness of the stress concentration portion is thicker than the other portions. Weight and cost can be reduced while maintaining high durability. In the method (2) for manufacturing a wheel disk, since the disk is rock-forged using a rocking punch having an uneven portion, a disk having a nonuniform thickness distribution in the circumferential direction is formed. Can be. In the method of manufacturing a wheel disk according to the above (3), by causing the swinging punch to perform a chrysanthemum motion, it is possible to prevent or suppress the occurrence of a rotational deviation between the swinging punch and the material to be formed. it can. In the wheel disk manufacturing apparatus of the above (4), since the oscillating punch has irregularities at a plurality of locations in the circumferential direction, when the oscillating punch is oscillated, the thickness distribution becomes uneven in the circumferential direction. Can be formed.

[0006]

FIG. 1 shows a wheel disc according to an embodiment of the present invention, and FIG. 2 shows a wheel disc according to another embodiment of the present invention. It is known from the results of analysis by a finite element method that stress is concentrated on a general wheel at a corner R portion of a decorative hole, a welded joint between a rim and a disc, a portion where a wheel is attached to a vehicle, and the like. In addition, since these stress concentration portions are formed by plastic working such as punching, notches are also likely to occur in the manufacturing process. Therefore, these parts are parts where it is difficult to secure stable high quality in terms of fatigue strength.

The wheel disk 10 according to the embodiment of the present invention
Covers wheel discs made by molding from a plate, excluding cast wheels. As shown in FIGS. 1 and 2, the wheel disc 10 according to the embodiment of the present invention has an uneven thickness distribution in the circumferential direction of the wheel disc. It is set to be large compared to the thickness of the part that does not.

In the wheel disc 10 shown in FIG. 1, the stress concentration site where the thickness is increased is a portion 12 around the decorative window 11.
As shown in the AA cross section, in the disk circumferential direction, the thickness of this portion 12 is
It is said to be larger than the plate thickness. In the disk radial direction, B
As shown in the -B cross section, the plate thickness of the mounting portion 14 of the disk on which the stress is concentrated to the hub is large, and it is desirable that the thickness be reduced toward the outer periphery in the radial direction. However, there is no need to change the thickness in the radial direction.

The wheel disk 10 shown in FIG. 2 is a wheel disk for large wheels for buses and trucks.
The mounting portion 14 for the hub is formed as a plate thickness increasing portion 16 by forming a groove 17 in a portion between the adjacent nut seats 15 and bringing the thickness thereof closer. Part 1 around nut seat 15
Reference numeral 6 denotes a portion where stress is concentrated, which is a portion having a greater thickness than the groove 17 in the circumferential direction of the disk.

In the wheel disk 10 having the above-described structure, the plate thickness is changed in the circumferential direction to increase the plate thickness at the stress concentration portion. It becomes smaller and the fatigue strength is improved. In addition, since the thickness is not increased over the entire circumferential direction, the weight is significantly reduced while maintaining the strength compared to the conventional case where the thickness is increased over the entire circumferential direction to obtain fatigue strength. And cost reduction. In addition, in the case of the structure shown in FIG. 2, the stress is reduced by increasing the plate thickness of the portion 16, and the mounting nut is prevented from loosening due to the decrease in the plate thickness due to the groove 17.

[0011] In a wheel disk manufactured from the forming of a plate, there has been no wheel disk having a change in thickness in the circumferential direction. The reason for this is that in spinning, the roll is rotated while rotating relative to the workpiece. This is because the work is uniformly processed in the circumferential direction, and the shape and the thickness of the work cannot be locally changed in the circumferential direction. This is because a large pressing force required to increase the thickness of the entire stress concentration site cannot be obtained with a conventional press. However, the method of the embodiment of the present invention makes it possible to manufacture a wheel disk having a thickness change in the circumferential direction by swing forging using a swing punch having a special shape,
In addition, manufacturing with a relatively small processing force is enabled.

The method of manufacturing a wheel disc according to the embodiment of the present invention is a method of forming a wheel disc 10 having an uneven thickness distribution in the circumferential direction of a wheel disc by rocking forging, as shown in FIGS. Yes, swinging punch 21
A plurality of uneven portions 22 for changing the thickness of the wheel disk 10 are formed in the circumferential direction of the swinging punch,
While oscillating the oscillating punch 21, the wheel disc 10
Is formed. In the swinging of the swinging punch 21, the swinging punch 21 is not rotated around the swinging punch shaft 23, and the swinging punch shaft 23 is moved by the swing forging device 2.
It is swung with respect to the 0 axis 24.

The swing forging device shaft 2 of the swing punch shaft 23
When the swinging punch shaft 23 is rotated around the swing forging device shaft 24 in FIG. 3, the swinging punch shaft 23 is moved with respect to the swing forging device shaft 24 in FIG. When the swinging punch shaft 23 is moved in a chrysanthemum petal shape around the swing forging device shaft 24 in FIG. Swing caused by a chrysanthemum motion that swings with respect to the swing forging apparatus shaft center 24. In the swing of the chrysanthemum motion, the locus of the pressing center of the swing punch 21 also has a petal shape of chrysanthemum as shown in FIG.

In the swing forging, the pressurized area 25 (for example, the hatched area in the example of FIG. 3) of the swing punch 21 sequentially moves in accordance with the swing of the swing punch 21 and swings out of the disk material. Only the portion of the dynamic punch 21 in the pressing area is shaped and the thickness is increased or decreased. Since the pressure forming area is only a part in the circumferential direction of the disk, the load required for forming the disk shape and increasing or decreasing the thickness of the disk (compared to the conventional press forming in the entire circumferential direction). Force) is small and in the range of forming and increasing / decreasing the plate thickness from the capacity of the apparatus.

FIG. 3 and FIG. 4 show a case where the part including the part where the decorative window is opened and the part around it is the part 26 in which the thickness is to be changed in the swing forging. The oscillating punch 21 is formed with an uneven portion 22 at a position where the oscillating punch 21 comes into pressure contact with the portion 26 during oscillating forging. When the portion 26 is a portion where the plate thickness is to be increased (a portion around the decorative window), the uneven portion 22 is formed of a concave portion, and the portion 26 is a portion where the plate thickness is to be reduced (a portion between the nut seats). In this case, it is composed of convex portions. During the rocking forging, when a portion 26 whose thickness is to be changed enters the pressurized region 25, the portion 26 is changed in thickness.

In the swing forging, since the swing punch 21 is not rotated around the swing punch axis 23, the position of the concave / convex portion 22 of the swing punch 21 and the portion 26 where the thickness of the disk material is desired to be changed are shifted. No or hard to slip.
However, since the rotation of the oscillating punch 21 around the oscillating punch shaft center 23 is not positively stopped, the disk material is subjected to the circumferential component of the reaction force from the concave and convex portions 22 of the oscillating punch 21 and the disk material is removed. 3 may be displaced in the circumferential direction.
The position of the portion 26 where the thickness of the disk material is to be changed may be shifted during swing forging.

However, in the rocking forging of the chrysanthemum motion shown in FIG. 4, when the chrysanthemum petal drawn by the center locus of the spherical bearing shown in FIG. It was confirmed by a test that the position of the uneven portion 22 of the swing punch 21 and the portion 26 of the disk material where the thickness of the disk material is desired to be changed did not shift during the swing forging. It is considered that the reason is that the reaction force from the uneven portion 22 of the swing punch 21 does not push the disk material in the circumferential direction. Therefore, in the swing forging, it is desirable to make the swing punch 21 perform a chrysanthemum motion from the viewpoint of preventing displacement.

In the above method for manufacturing a wheel disc,
Since the disk is rock-forged using the rocking punch 21 having the irregularities 22 formed thereon, the disk 10 having a thickness distribution that is non-uniform in the circumferential direction can be formed. Moreover, a much smaller forming load is required as compared with a press.

FIGS. 5 and 6 show a wheel disc manufacturing apparatus comprising an oscillating forging apparatus 20 for manufacturing a wheel disc 10 having an uneven thickness distribution in the circumferential direction of the wheel disc according to the embodiment of the present invention. I have. This wheel disk production leaving comprises a pair of dies and a swing mechanism.
The pair of dies includes an oscillating punch 21 and an opposing dies 27 for oscillating punches, each having a plurality of uneven portions 22 formed in the circumferential direction of the oscillating punch for changing the thickness of the wheel disk 10. The swing mechanism is connected to the swing punch 21 via a spherical bearing 32 and has two motors 28 and 29 and two eccentric rotors 30 and 31 to swing the swing punch 21.

The wheel disk manufacturing apparatus further has a hydraulic cylinder 33 for urging one of the swinging punch 21 and the facing die 27 toward the other. In addition, facing type 27
Has a center guide 34 for preventing the disc material from being displaced in the radial direction during the rocking forging.
Is engaged. The uneven portion 22 of the swing punch 21 is formed at a portion corresponding to a portion where the thickness of the wheel disc is to be increased or decreased. In FIG. 5, a recess is formed in the swing punch 21 in order to increase the thickness around the decorative window. The case where it was formed is shown.

The swinging punch 21 has an arm 21 extending upward.
a. In addition, the spherical bearing 32 has an inner member and an outer member that are in sliding contact with each other on a spherical contact surface.
The arm 21a is held at its upper end by the inner member of the spherical bearing 32. The eccentric rotor 30 has a circular outer peripheral surface and a circular inner peripheral surface, and the outer peripheral surface and the inner peripheral surface of the eccentric rotor 30 are eccentric to each other. Similarly, the eccentric rotor 31 has a circular outer peripheral surface and a circular inner peripheral surface, and the outer peripheral surface and the inner peripheral surface of the eccentric rotor 31 are eccentric to each other.

The eccentric rotor 30 has a frame 35 on its outer peripheral surface.
Rotatably supported by the eccentric rotor 30
A sliding contact surface between the frame and the frame 35 serves as a bearing 36. The outer peripheral surface of the eccentric rotor 31 is slidably in contact with the inner peripheral surface of the eccentric rotor 30, and the sliding surface is a bearing 37. Further, the outer peripheral surface of the outer member of the spherical bearing 32 slidably contacts the inner peripheral surface of the eccentric rotor 31, and the sliding surface is a bearing 38. The center of the inner peripheral surface of the eccentric rotor 31 matches the center of the spherical bearing 32. However, the outer member and the inner member of the spherical bearing 32 are concentric with each other. The eccentric rotor 30 is rotated by a motor 28, and the eccentric rotor 31 is rotated by a motor 29.

With this structure, the center of the spherical bearing 32 can take an arbitrary position inside the maximum circle (the circle in FIG. 6) that can be obtained by combining the rotation angles of the eccentric rotors 30, 31. Therefore, it is possible to cause the swing punch 21 to perform any swing (rotational motion, chrysanthemum motion, etc.).

When the eccentric rotor 30 is rotated forward and the eccentric rotor 31 is rotated reversely, with the eccentric rotor 30 having the eccentric amount AB = r and the eccentric rotor 31 having the eccentric amount CD = r, the upper end of the arm 21a is closed. The locus of the center of the spherical bearing 32 (x,
y) is represented by the following equation. x = r · cos (ω _o · t) + r · cos (ω _i · t−
ω _o · t) y = −r · sin (ω _o · t) + r · sin (ω _i · t
−ω _o · t) where t: time ω _o : angular velocity of the eccentric rotor 30 (clockwise is positive) ω _i : angular velocity of the eccentric rotor 31 (positive in the counterclockwise direction) r: eccentricity of the eccentric rotor 30 Amount = Eccentric amount of eccentric rotor 31

FIG. 6 shows a spherical bearing 32 in the case of chrysanthemum motion.
Of the center of (x, y). In FIG.
The trajectory is drawn in the order of 2, 3, 4, and 5. In order for the starting point and the ending point of the trajectory to coincide with each other to obtain a beautiful petal, the following relationship is established between ω _i and ω _o , where n is an integer.
Choose ω _i and ω _o . ω _i = n · (ω _i −2ω _o ) By drawing a beautiful petal trajectory, it is possible to prevent the swing punch 21 and the disk material 10 from being displaced in the rotation direction during the swing forging. Confirmed by testing.

The above-described manufacturing apparatus has the oscillating punch 21 having a plurality of irregularities 22 at a plurality of positions in the circumferential direction. The oscillating punch 21 is oscillated by an oscillating mechanism, and the opposing mold 27 is oscillated by the oscillating patch. Since the disk material is molded while being urged toward the 21 side, the thickness of the disk material can be changed in the circumferential direction, and the disk material can be provided with a plurality of circumferentially increased thickness, increased thickness, or reduced thickness portions. Can be molded. In particular, when the swinging punch 21 is caused to perform chrysanthemum motion, displacement of the swinging punch 21 and the disk material 10 in the rotating direction during the swing forging can be prevented, and a beautiful molding can be performed.

[0027]

According to the wheel disc of the first aspect, the thickness of the disc is not uniform even in the circumferential direction of the disc, and the thickness of the stress-concentrated portion is larger than that of the other portions. The weight and cost can be reduced while maintaining the required durability. In the method for manufacturing a wheel disk according to the second aspect, since the disk is rock-forged using a rocking punch having an uneven portion, it is possible to form a disk having a nonuniform thickness distribution in the circumferential direction. it can. In the method of manufacturing a wheel disk according to the third aspect, by causing the swinging punch to perform the chrysanthemum motion, it is possible to prevent or suppress occurrence of a rotational direction shift between the swinging punch and the material to be formed. . In the wheel disk manufacturing apparatus according to the fourth aspect, since the oscillating punch has uneven portions at a plurality of positions in the circumferential direction, when the oscillating punch is oscillated, the thickness distribution that becomes uneven in the circumferential direction is reduced. Can be molded.

[Brief description of the drawings]

FIG. 1 is an AA diagram of a wheel disc according to an embodiment of the present invention.
It is a partial front view accompanying a cross section and a BB cross section.

FIG. 2 is a partial front view of a wheel disk according to another embodiment of the present invention, taken along a line CC.

FIG. 3 is a front view of the wheel disc showing an example (rotational motion) of a pressing locus in the method of manufacturing a wheel disc according to one embodiment of the present invention.

FIG. 4 is a front view of the wheel disc illustrating another example (chrysanthemum motion) of the pressing locus in the method of manufacturing the wheel disc according to the embodiment of the present invention.

FIG. 5 is a sectional view of an apparatus for manufacturing a wheel disk according to an embodiment of the present invention.

6 is a locus diagram of a center of a spherical bearing when chrysanthemum motion is performed by the apparatus of FIG. 5;

FIG. 7 is a manufacturing process diagram of a conventional wheel disk.

FIG. 8 is a partial cross-sectional view of a wheel disk manufactured by a conventional manufacturing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Wheel disk 11 Decorative window 20 Oscillating forging device 21 Oscillating punch 22 Irregular part 26 The part which wants to change board thickness 27 Facing type 28, 29 Motor 30, 31 Eccentric rotor 32 Spherical bearing

Claims (4)

[Claims] 1. A wheel disk manufactured by molding a plate, wherein the plate has a non-uniform thickness distribution in the circumferential direction of the wheel disk, and the thickness of the stress-concentrated portion in the circumferential direction is such that the stress is not concentrated. A wheel disc that is considered to be large compared to its thickness. 2. A method for forming a wheel disc having a non-uniform thickness distribution in the circumferential direction of a wheel disc by swing forging, wherein the swing punch is provided with an uneven portion for changing the thickness of the wheel disc. A method of manufacturing a wheel disc, wherein a plurality of portions are formed in a circumferential direction of a swinging punch and a wheel disc is formed while swinging the swinging punch. 3. The method according to claim 2, wherein the swing of the swing punch is a chrysanthemum motion. 4. An apparatus for manufacturing a wheel disc having a non-uniform thickness distribution in a circumferential direction of a wheel disc, wherein a plurality of concave and convex portions for varying the thickness of the wheel disc are formed in the circumferential direction of the swinging punch. A swinging punch and a facing type of the swinging punch, and a swinging mechanism coupled to the swinging punch and having at least one motor and at least one eccentric rotor for swinging the swinging punch. Equipment for manufacturing wheel discs.