JP2015039712A

JP2015039712A - Manufacturing method of vehicle wheel disc

Info

Publication number: JP2015039712A
Application number: JP2013171911A
Authority: JP
Inventors: 浩二竹内; Koji Takeuchi; 喜久也伊藤; Kikuya Ito; 啓生鈴井; Yoshio Suzui
Original assignee: Topy Industries Ltd
Current assignee: Topy Industries Ltd
Priority date: 2013-08-22
Filing date: 2013-08-22
Publication date: 2015-03-02
Anticipated expiration: 2033-08-22
Also published as: JP6162540B2

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a vehicle wheel disc which can eliminate the post-processing of a portion which becomes a hub attachment part after processing a cylinder ring into a dish shape.SOLUTION: A manufacturing method of a vehicle wheel disc comprises: (a) a cylindrical material forming process which forms a rectangular material by cutting a plate material, rounds the rectangular material, butt-welds both ends of the rectangular material, and forms a cylindrical material 6; (b) a squeezing process which squeezes one end of the cylindrical material 6, and forms a first cylindrical molding 11 having a disc-plate shaped bottom part 11a at which a hole 11b is opened at a center part which is obtained by molding a portion becoming a hub attachment part into a substantially-equal thickness; (c) an ironing process which forms a ring-shaped bottomed second molding 12 having an unequal thickness by ironing at least a part of a cylinder part 11c of the first molding 11 by a squeezing device 50 having a punch 51 and a die 52; and (d) a diameter-expanding process which expands a diameter of a cylinder portion 12c of the second molding 12, forms the cylinder portion 12c into a conical shape, and also forms it into a disc shape.

Description

本発明は、車両用ホイールディスクの製造方法に関する。 The present invention relates to a method for manufacturing a wheel disc for a vehicle.

円筒環から作成される車両用ホイールディスクは、従来、板厚一定の矩形材を丸めた後、矩形材の両端を溶接することにより円筒環を作成し、この円筒環をプレス成形して穴を有する底部と底部から立ち上がる立ち上がり部とを備える皿状にし、立ち上がり部を、パンチと側面が凹凸面とされたしごきダイスとを用いてしごき加工することにより立ち上がり部の板厚を薄くするとともに最終ディスク形状にした後、ハブ穴抜き、ボルト穴抜き、飾り穴抜き加工して、製造されていた（特許文献１参照）。 Conventionally, a vehicle wheel disc made from a cylindrical ring is made by rounding a rectangular material having a constant thickness and then welding both ends of the rectangular material to create a cylindrical ring. The bottom disk has a bottom plate with a bottom portion and a rising portion rising from the bottom portion, and the rising portion is processed by ironing using a punch and an ironing die whose side surface is uneven. After making it into a shape, it was manufactured by hub hole punching, bolt hole punching, and decorative hole punching (see Patent Document 1).

しかし、従来の車両用ホイールディスクの製造方法には、つぎの問題点がある。
（Ａ）円筒環をプレス成形して皿状に成形すると、円筒部を縮径するため、板厚が増し、ハブ取付け部となる部分が不等厚になってしまう。縮径後にロールによる平坦化を行っても、充分に平坦化できず、そのため、切削などの後加工でハブ取付け部となる部分を平滑等厚にする必要がある。また、縮径量が多く、しわが発生したり、波打ちが発生したりしやすい。そのため、不良品が発生しやすい。 However, the conventional method for manufacturing a wheel disc for a vehicle has the following problems.
(A) When the cylindrical ring is press-molded and formed into a dish shape, the diameter of the cylindrical portion is reduced, so that the plate thickness increases and the portion serving as the hub mounting portion becomes unequal. Even if flattening with a roll is performed after the diameter reduction, it cannot be sufficiently flattened. For this reason, it is necessary to make the portion to be a hub attachment portion smooth and uniform in post-processing such as cutting. In addition, the amount of diameter reduction is large, and wrinkles or undulations are likely to occur. Therefore, defective products are likely to occur.

（Ｂ）しごき加工により立ち上がり部全体の板厚を薄くするため、しごき加工した円筒状部分を円錐状に広げる場合に、材料に割れが発生しやすい。 (B) Since the plate | board thickness of the whole standing | starting-up part is made thin by ironing, when expanding the iron-processed cylindrical part to cone shape, it is easy to generate | occur | produce a crack in material.

特開２０１０−０５８１２５号公報JP 2010-058125 A

本発明の目的は、円筒環を皿状に加工した後にハブ取付け部となる部分の後加工を不用にでき、材料の割れを無くすことができる車両用ホイールディスクの製造方法を提供することにある。 An object of the present invention is to provide a method for manufacturing a vehicle wheel disk that can eliminate the need for post-processing of a portion that becomes a hub mounting portion after processing a cylindrical ring into a dish shape and eliminates cracks in the material. .

上記目的を達成する本発明はつぎの通りである。
（１）板材を切断して矩形材を作成し、前記矩形材を丸め両端部を突合せ溶接して円筒状素材を作成する円筒状素材作成工程と、
前記円筒状素材を一端口絞りして、ハブ取付け部となる部分をほぼ等厚に成形して得た中央部に孔の開いた円板状の底部を有する円筒状の第１成形品を作成する口絞り工程と、
パンチと、ダイを有するしごき装置にて、前記第１成形品の円筒部の少なくとも一部をしごき加工して不等厚有底環状の第２成形品を作成するしごき工程と、
前記第２成形品の円筒部分を拡径して該円筒部分を円錐形状として、ディスク形状とする拡径工程と、
を有する、車両用ホイールディスクの製造方法。
（２）前記しごき工程は、前記第１成形品を、しごき装置にて、前記第１成形品の前記円筒部の開口端部側はしごき加工をしないかしごき率を１０％以下にしごき加工することにより成形して不等厚有底環状の前記第２成形品を作成する工程からなる、（１）記載の車両用ホイールディスクの製造方法。
（３）前記口絞り工程は、一対の上下型を相対接近させながら上型を下型軸芯に対して揺動させて、前記円筒状素材を一端口絞りして、ハブ取付け部となる部分をその後の加工無しに平滑に所定の厚みに等厚に成形して前記第１成形品を作成する工程からなる、（１）または（２）記載の車両用ホイールディスクの製造方法。
（４）前記円筒状素材を一端口絞りして前記第１成形品を作成する前記口絞り工程では、前記円筒状素材の他端の直径を変化させずに前記第１成形品を作成する、（１）〜（３）のいずれか１つに記載の車両用ホイールディスクの製造方法。
（５）前記拡径工程では、前記第２成形品の前記円筒部分を拡径するとともに、前記しごき工程で内径側に付与されていた凹凸形状を外径側へと押し出す、（１）〜（４）のいずれか１つに記載の車両用ホイールディスクの製造方法。
（６）前記拡径工程の後に、
リム取付けフランジとなる部分を絞り加工またはしごき絞り加工して、リム取付けフランジを成形するフランジ成形工程を有する、（１）〜（５）のいずれか１つに記載の車両用ホイールディスクの製造方法。
（７）前記口絞り工程では、ハブ取付け部となる前記第１成形品の部分を平面化、板厚均一化するように揺動鍛造を行なう、（１）〜（６）のいずれか１つに記載の車両用ホイールディスクの製造方法。
（８）前記口絞り工程では、前記第１成形品の前記円筒部の板厚を薄くするように揺動鍛造を行なう、（１）〜（７）のいずれか１つに記載の車両用ホイールディスクの製造方法。
（９）前記口絞り工程は、プレスにて予成形を行いハブ取付け部となる部分を内径側に曲げた後に、揺動鍛造を行い前記第１成形品を作成する、（１）〜（８）のいずれか１つに記載の車両用ホイールディスクの製造方法。 The present invention for achieving the above object is as follows.
(1) A cylindrical material creating step of creating a rectangular material by cutting a plate material, rounding the rectangular material and butt welding both ends,
A cylindrical first molded product having a disk-shaped bottom part with a hole in the center part obtained by narrowing one end of the cylindrical material and molding a part to be a hub mounting part to have an almost equal thickness is prepared. A mouth-squeezing process,
An ironing step of ironing at least a part of the cylindrical portion of the first molded product with a punch and an ironing device having a die to produce an annular second molded product with an unequal thickness;
Expanding the cylindrical portion of the second molded product to make the cylindrical portion conical, and increasing the diameter of the disc,
A method for manufacturing a wheel disc for a vehicle, comprising:
(2) In the ironing step, the first molded product is ironed with an ironing device so that the ironing rate is 10% or less without performing ironing on the opening end side of the cylindrical portion of the first molded product. The manufacturing method of the wheel disk for vehicles as described in (1) which consists of the process which shape | molds by this and produces the said 2nd molded product of unequal thickness bottomed cyclic | annular form.
(3) In the mouth-squeezing step, the upper die is swung with respect to the lower die shaft while the pair of upper and lower dies are relatively approached, and the cylindrical material is squeezed at one end to become a hub mounting portion. The method for manufacturing a wheel disc for a vehicle according to (1) or (2), comprising the step of forming the first molded product by forming the first molded product smoothly into a predetermined thickness without any subsequent processing.
(4) In the mouth-squeezing step of creating the first molded product by squeezing one end of the cylindrical material, creating the first molded product without changing the diameter of the other end of the cylindrical material, (1) The manufacturing method of the wheel disc for vehicles as described in any one of (3).
(5) In the diameter expansion step, the cylindrical portion of the second molded product is expanded in diameter, and the uneven shape imparted to the inner diameter side in the ironing step is pushed out to the outer diameter side, (1) to ( 4) The manufacturing method of the wheel disc for vehicles as described in any one of 4).
(6) After the diameter expansion step,
The method for manufacturing a wheel disc for a vehicle according to any one of (1) to (5), further including a flange forming step of forming a rim mounting flange by drawing or ironing a portion to be a rim mounting flange. .
(7) In the squeezing step, swing forging is performed so that the portion of the first molded product that becomes the hub attachment portion is planarized and the plate thickness is uniformed. Any one of (1) to (6) The manufacturing method of the wheel disc for vehicles as described in any one of.
(8) The vehicle wheel according to any one of (1) to (7), wherein in the mouth drawing step, swing forging is performed so as to reduce a plate thickness of the cylindrical portion of the first molded product. Disc manufacturing method.
(9) The mouth-drawing step is performed by pre-forming with a press and bending the portion to be the hub mounting portion toward the inner diameter side, and then performing swing forging to create the first molded product. (1) to (8 The manufacturing method of the wheel disc for vehicles as described in any one of 1).

上記（１）の車両用ホイールディスクの製造方法によれば、口絞り工程ではハブ取付け部となる部分をほぼ等厚に成形するため、ハブ取付け部となる部分の後加工は不用である。 According to the vehicle wheel disc manufacturing method of (1) above, since the portion that becomes the hub attachment portion is formed to have substantially the same thickness in the mouth drawing step, post-processing of the portion that becomes the hub attachment portion is unnecessary.

上記（２）の車両用ホイールディスクの製造方法によれば、しごき工程では第１成形品の円筒部の開口端部側はしごき加工をしないかしごき率を１０％以下にしごき加工するため、第１成形品の円筒部の開口端部側の加工硬化を抑制できる。そのため、拡径工程で材料割れが発生することを抑制できる。 According to the vehicle wheel disk manufacturing method of (2) above, the opening end side of the cylindrical portion of the first molded product is not ironed in the ironing process, and the ironing is performed with a ironing ratio of 10% or less. Work hardening on the opening end side of the cylindrical portion of one molded product can be suppressed. Therefore, it can suppress that a material crack generate | occur | produces in a diameter expansion process.

上記（３）の車両用ホイールディスクの製造方法によれば、口絞り工程では揺動鍛造が行なわれる。そのため、プレス成形ではできない精度でハブ取付け部となる部分を平滑等厚に成形できる。そのため、ハブ取付け部となる部分の後加工を不要とすることができる。 According to the vehicle wheel disc manufacturing method of (3) above, rocking forging is performed in the aperture drawing step. Therefore, the portion that becomes the hub mounting portion can be formed to a smooth and uniform thickness with an accuracy that cannot be achieved by press molding. Therefore, post-processing of the portion that becomes the hub attachment portion can be made unnecessary.

上記（４）の車両用ホイールディスクの製造方法によれば、円筒状素材を一端口絞りして第１成形品を作成する口絞り工程では、円筒状素材の他端の直径を変化させずに第１成形品を作成するため、円筒状素材の他端の加工硬化を抑制できる。そのため、拡径工程で材料割れが発生することを抑制できる。 According to the vehicle wheel disk manufacturing method of (4) above, in the mouth drawing step of making the first molded product by drawing the cylindrical material at one end, the diameter of the other end of the cylindrical material is not changed. Since the first molded product is created, work hardening at the other end of the cylindrical material can be suppressed. Therefore, it can suppress that a material crack generate | occur | produces in a diameter expansion process.

上記（５）の車両用ホイールディスクの製造方法によれば、拡径工程では、しごき工程で内径側に付与されていた凹凸形状を外径側へと押し出すため、ホイールを車両に搭載する際にホイールディスクがブレーキと干渉することを抑制できる。 According to the vehicle wheel disc manufacturing method of (5) above, when the wheel is mounted on the vehicle, the concavo-convex shape imparted to the inner diameter side in the ironing process is pushed out to the outer diameter side in the diameter expansion process. It is possible to suppress the wheel disc from interfering with the brake.

上記（６）の車両用ホイールディスクの製造方法によれば、拡径工程の後にフランジ成形工程を有するため、精度の良いリム取付けフランジを得ることができる。 According to the vehicle wheel disk manufacturing method of (6) above, since the flange forming step is provided after the diameter expanding step, a highly accurate rim mounting flange can be obtained.

上記（７）の車両用ホイールディスクの製造方法によれば、口絞り工程では、ハブ取付け部となる第１成形品の部分を平面化、板厚均一化するように揺動鍛造を行なうため、揺動鍛造にてハブ取付け部となる部分を等厚に成形できる。 According to the vehicle wheel disk manufacturing method of (7) above, in the aperture drawing process, the forging is performed so that the portion of the first molded product that becomes the hub mounting portion is flattened and the plate thickness is made uniform. A portion to be a hub mounting portion can be formed with a uniform thickness by swing forging.

上記（８）の車両用ホイールディスクの製造方法によれば、口絞り工程では第１成形品の円筒部の板厚を薄くするように揺動鍛造を行なうため、しごき工程において第１成形品の円筒部をしごく量を減らすことができる。そのため、しごき工程でしごき加工を容易に行なうことができる。 According to the vehicle wheel disc manufacturing method of (8) above, since the swing forging is performed so as to reduce the plate thickness of the cylindrical portion of the first molded product in the mouth drawing process, The amount of squeezing of the cylindrical portion can be reduced. Therefore, the ironing process can be easily performed in the ironing process.

上記（９）の車両用ホイールディスクの製造方法によれば、口絞り工程では、プレスにて予成形を行いハブ取付け部となる部分を内径側に曲げた後に、揺動鍛造を行い第１成形品を作成するため、予成形を行わない場合に比べて揺動鍛造を容易に行なうことができる。 According to the vehicle wheel disc manufacturing method of (9) above, in the aperture drawing process, after pre-forming with a press and bending the portion that becomes the hub mounting portion to the inner diameter side, swing forging is performed to perform the first forming. Since the product is produced, the swing forging can be easily performed as compared with the case where the preforming is not performed.

本発明実施例の車両用ホイールディスクの製造方法における、円筒状素材作成工程の工程図である。なお、各装置のハッチングは図面の明瞭化のために省略している。図２以降も同様。（ａ）は、平板状の矩形材を示す。（ｂ）は、矩形材が筒状巻かれる状態を示す。（ｃ）は、巻きの両端部を溶接接合する状態を示す。（ｄ）は、溶接部の盛り上がりとバリをトリミングする状態を示す。（ｅ）は、円筒状素材を示す。It is process drawing of the cylindrical raw material preparation process in the manufacturing method of the wheel disc for vehicles of this invention Example. Note that hatching of each device is omitted for clarity of the drawings. The same applies to FIG. (A) shows a flat rectangular material. (B) shows the state by which a rectangular material is wound cylindrically. (C) shows the state which welds and joins both ends of the winding. (D) shows a state in which the bulge and burrs of the welded portion are trimmed. (E) shows a cylindrical material. 本発明実施例の車両用ホイールディスクの製造方法における、口絞り工程と、しごき工程と、拡径工程と、フランジ成形工程の工程図である。（ａ）は、円筒状素材を示す。（ｂ）、（ｃ）は、口絞り工程を示す。（ｄ）は、しごき工程を示す。（ｅ）は、拡径工程を示す。（ｆ）は、フランジ成形工程を示す。なお、（ｄ）、（ｅ）、（ｆ）において、左半分は成形前、右半分は成形後を示す。It is process drawing of a mouth-drawing process, an ironing process, a diameter expansion process, and a flange formation process in the manufacturing method of the wheel disc for vehicles of the present invention example. (A) shows a cylindrical raw material. (B), (c) shows a squeezing process. (D) shows an ironing process. (E) shows a diameter expansion process. (F) shows a flange forming process. In (d), (e), and (f), the left half indicates before molding and the right half indicates after molding. 図２（ｂ）の拡大図である。FIG. 3 is an enlarged view of FIG. 図２（ｃ）の拡大図である。FIG. 3 is an enlarged view of FIG. 図２（ｄ）の拡大図である。なお、左半分は成形前、右半分は成形後を示す。FIG. 3 is an enlarged view of FIG. The left half shows before molding and the right half shows after molding. 図２（ｅ）の拡大図である。なお、左半分は成形前、右半分は成形後を示す。FIG. 3 is an enlarged view of FIG. The left half shows before molding and the right half shows after molding. 図２（ｆ）の拡大図である。なお、左半分は成形前、右半分は成形後を示す。FIG. 3 is an enlarged view of FIG. The left half shows before molding and the right half shows after molding. 本発明実施例の車両用ホイールディスクの製造方法における、拡径工程後であってフランジ成形工程前にしごき工程で内径側に付与されていた凹凸形状を外径側へ押し出す成形を行う場合の、成形装置の断面図である。なお、左半分は成形前、右半分は成形後を示す。In the vehicle wheel disk manufacturing method of the embodiment of the present invention, in the case of performing the extrusion to the outer diameter side after the diameter expansion process and before the flange molding process, the concave and convex shape provided on the inner diameter side in the ironing process, It is sectional drawing of a shaping | molding apparatus. The left half shows before molding and the right half shows after molding. 本発明実施例の車両用ホイールディスクの製造方法における、口絞り工程にて第１成形品の円筒部の板厚を薄くするように揺動鍛造を行なう場合の、揺動鍛造装置の断面図である。In the manufacturing method of the wheel disc for vehicles of this invention Example, it is sectional drawing of a rocking forge device in the case of performing rocking forging so that the plate | board thickness of the cylindrical part of a 1st molded product may be made thin in a mouth drawing process. is there. 本発明実施例の車両用ホイールディスクの製造方法における、口絞り工程でプレスにて予成形を行う場合の、プレス装置の断面図である。なお、左半分は成形前、右半分は成形後を示す。It is sectional drawing of a press apparatus in the case of performing preforming with a press by a mouth-drawing process in the manufacturing method of the wheel disk for vehicles of this invention Example. The left half shows before molding and the right half shows after molding. ホイールディスクの材料として５９０Ｍｐａ材、３７０Ｍｐａ材、４４０Ｍｐａ材を用いた場合の、しごき工程における円筒部の開口端部側のしごき率と拡径工程で発生する材料割れとの関係を示す表である。It is a table | surface which shows the relationship between the ironing rate by the side of the opening end part of the cylindrical part in the ironing process, and the material crack which generate | occur | produces at a diameter expansion process at the time of using 590 Mpa material, 370 Mpa material, and 440 Mpa material as a material of a wheel disk. 本発明実施例のホイールディスクの製造方法によって製造されるホイールディスクの断面図である。It is sectional drawing of the wheel disc manufactured by the manufacturing method of the wheel disc of an Example of this invention.

以下に、図１〜図１２を参照して、本発明実施例の車両用ホイールディスクの製造方法を説明する。 Below, with reference to FIGS. 1-12, the manufacturing method of the wheel disk for vehicles of this invention Example is demonstrated.

先ず、本発明実施例の製造方法によって製造されるホイールディスク１０について説明する。
ホイールディスク１０は、トラック、バスなどの大中型ホイールディスクであり、ダブル取り付けが可能なホイールディスクである。ただし、ホイールディスク１０は、乗用車、商用車、産業車両などのホイールディスクであってもよい。ホイールディスク１０は、図１に示すような平板状のディスク素材から製造されるディスクが対象である。ホイールディスク１０は、鋳造品ではない。ホイールディスク１０は、たとえばスチール製である。ただし、ホイールディスク１０は、スチール製でなくてもよく、アルミ合金製、チタン合金製、マグネシウム合金製等であってもよい。ホイールディスク１０は、図示略の環状のリム（図示略のタイヤを保持する部分）とは別に製造されており、リムと溶接されて、またはリベット、接着等で接合されてホイールになる。 First, the wheel disc 10 manufactured by the manufacturing method of the embodiment of the present invention will be described.
The wheel disk 10 is a large-medium type wheel disk such as a truck or a bus, and is a wheel disk that can be double-mounted. However, the wheel disc 10 may be a wheel disc of a passenger car, a commercial vehicle, an industrial vehicle, or the like. The wheel disk 10 is a disk manufactured from a flat disk material as shown in FIG. The wheel disc 10 is not a cast product. The wheel disc 10 is made of steel, for example. However, the wheel disk 10 may not be made of steel, but may be made of aluminum alloy, titanium alloy, magnesium alloy, or the like. The wheel disc 10 is manufactured separately from an unillustrated annular rim (a portion for holding a not-illustrated tire), and is welded to the rim or joined by rivets, adhesion, or the like to form a wheel.

ホイールディスク１０は、図１２に示すように、図示略のハブに取付けられるハブ取付け部（平板部といってもよい）２０と、ハブ取付け部２０の外周部からディスク軸方向（ホイール軸方向）に立ち上がる立ち上がり部（側壁部といってもよい）３０と、を有する。 As shown in FIG. 12, the wheel disc 10 includes a hub attachment portion (also referred to as a flat plate portion) 20 attached to a hub (not shown), and a disc axial direction (wheel axis direction) from the outer peripheral portion of the hub attachment portion 20. And a rising portion (may be referred to as a side wall portion) 30 standing up.

ハブ取付け部２０は、ダブル取り付けおよびシングル取り付けともに可能なように通常、平板状（略平板状を含む）である。ハブ取付け部２０は、平板状である場合、ディスク軸方向（ホイール軸方向）と直交（略直交を含む）する平面内にある。ハブ取付け部２０には、ハブ穴２１と、ハブ取付けボルト穴２２と、が設けられている。 The hub mounting portion 20 is usually flat (including substantially flat) so that both double mounting and single mounting are possible. When the hub attachment portion 20 is flat, the hub attachment portion 20 is in a plane perpendicular to (including substantially perpendicular to) the disc axial direction (wheel axial direction). The hub mounting portion 20 is provided with a hub hole 21 and a hub mounting bolt hole 22.

ハブ穴２１は、ホイールディスク１０のディスク半径方向（ホイール半径方向）の中央部に設けられる。
ハブ取付けボルト穴２２は、ハブ取付け部２０のハブ穴２１の外周側にホイールディスク１０のディスク周方向（ホイール周方向）に同心円上等間隔に複数設けられる。 The hub hole 21 is provided at the center of the wheel disk 10 in the disk radial direction (wheel radial direction).
A plurality of hub mounting bolt holes 22 are provided on the outer peripheral side of the hub hole 21 of the hub mounting portion 20 at equal intervals on a concentric circle in the disk circumferential direction (wheel circumferential direction) of the wheel disk 10.

車両のハブから延びてくるハブ取付けボルト（両方共に図示略）をハブ取付けボルト穴２２に挿通し、ハブ取付けボルトに図示略のハブナットを螺合することにより、ホイールディスク１０（ホイール）はハブに固定される。 By inserting hub mounting bolts (both not shown) extending from the vehicle hub into the hub mounting bolt holes 22 and screwing hub nuts (not shown) into the hub mounting bolts, the wheel disc 10 (wheel) is fitted to the hub. Fixed.

立ち上がり部３０は、円錐状部３１と、リム取付けフランジ３２と、を備える。
円錐状部３１は、ハブ取付け部２０の外周部に連なる。円錐状部３１は、ハブ取付け部２０の外周部から、ディスク半径方向外側かつ立ち上がり部３０の立ち上がり量が大になる方向（ディスク軸方向に向かって）に、傾斜している。
円錐状部３１の少なくとも一部は、しごき加工による薄肉化が行なわれており、ディスク素材２の厚さより薄くなっている。円錐状部３１には、飾り穴３３が設けられている。飾り穴３３は、ホイールディスク１０のディスク周方向（ホイール周方向）に同心円上等間隔に複数設けられる。 The rising portion 30 includes a conical portion 31 and a rim mounting flange 32.
The conical portion 31 continues to the outer peripheral portion of the hub attachment portion 20. The conical portion 31 is inclined from the outer peripheral portion of the hub mounting portion 20 in the direction of the outer side in the disk radial direction and the rising amount of the rising portion 30 (in the direction of the disk axis).
At least a part of the conical portion 31 is thinned by ironing and is thinner than the thickness of the disk material 2. The conical portion 31 is provided with a decoration hole 33. A plurality of decoration holes 33 are provided at equal intervals on a concentric circle in the disk circumferential direction (wheel circumferential direction) of the wheel disk 10.

リム取付けフランジ３２は、立ち上がり部３０の立ち上がり方向（ディスク軸方向）の先端部（ディスク半径方向の外周部）にある。リム取付けフランジ３２は、図示略のリムの内周面に対して嵌合するように、全周にわたって連続する円筒状である。リム取付けフランジ３２は、しごき加工等によって、ディスク素材２の厚さよりも薄肉化が行なわれていてもよく行なわれていなくてもよい。ホイールディスク１０は、リム取付けフランジ３２で図示略のリムと溶接される。 The rim mounting flange 32 is located at the tip end portion (the outer peripheral portion in the disc radial direction) of the rising portion 30 in the rising direction (disk axial direction). The rim mounting flange 32 has a cylindrical shape that is continuous over the entire circumference so as to be fitted to the inner peripheral surface of a rim (not shown). The rim mounting flange 32 may or may not be thinner than the thickness of the disk material 2 by ironing or the like. The wheel disc 10 is welded to a rim (not shown) by a rim mounting flange 32.

円錐状部３１、特にリム取付けフランジ３２近傍に位置する円錐状部３１部分は、ホイールの剛性、応力の条件がハブ取付け部２０近傍と比較して負荷が低い。そのため、軽量化、材料コスト低減のため、ホイールディスク１０の円錐状部３１はハブ取付け部２０より薄くなっている。 The conical portion 31, particularly the conical portion 31 located near the rim mounting flange 32, has a lower load than the hub mounting portion 20 in terms of wheel rigidity and stress conditions. Therefore, the conical portion 31 of the wheel disc 10 is thinner than the hub mounting portion 20 in order to reduce the weight and reduce the material cost.

つぎに、ホイールディスク１０の製造方法について説明する。
ホイールディスク１０の製造方法は、
（ａ）図１に示すように、矩形材４を丸め両端部を突合せ溶接して円筒状素材６を作成する円筒状素材作成工程と、
（ｂ）図２（ｂ）、図２（ｃ）に示すように、円筒状素材６の一端を口絞りして、ハブ取付け部２０となる中央部に孔１１ｂの開いた底部１１ａを有する円筒状の第１成形品１１を作成する口絞り工程と、
（ｃ）図２（ｄ）に示すように、パンチ５１と、側面５２ａが凹凸面となったダイ５２を有するしごき装置５０にて、第１成形品１１の円筒部１１ｃの少なくとも一部をしごき加工して、不等厚有底環状の第２成形品１２を作成するしごき工程と、
（ｄ）図２（ｅ）に示すように、第２成形品１２の開口側を拡径して円筒部分１２ｃを円錐形状の円錐部１３ｃとして、第２成形品１２をディスク形状の第３成形品１３とする拡径工程と、
（ｅ）図２（ｆ）に示すように、リム取付けフランジ３２となる部分を絞り加工またはしごき絞り加工して、リム取付けフランジ３２を成形するフランジ成形工程と、
を有し、この工程の順に加工を行う。 Next, a method for manufacturing the wheel disc 10 will be described.
The manufacturing method of the wheel disc 10 is as follows:
(A) As shown in FIG. 1, a cylindrical material creating step of creating a cylindrical material 6 by rounding a rectangular material 4 and butt welding both ends,
(B) As shown in FIGS. 2 (b) and 2 (c), one end of the cylindrical material 6 is squeezed, and a cylinder having a bottom portion 11a having a hole 11b in the center portion serving as the hub mounting portion 20 A squeezing step for creating a first molded article 11 having a shape;
(C) As shown in FIG. 2 (d), at least a part of the cylindrical portion 11c of the first molded product 11 is ironed by a ironing device 50 having a punch 51 and a die 52 having a concave and convex surface 52a. An ironing process to process and create an unequal-thickness bottomed annular second molded article 12;
(D) As shown in FIG. 2 (e), the diameter of the opening side of the second molded product 12 is increased so that the cylindrical portion 12c serves as a conical cone portion 13c, and the second molded product 12 is formed into a disc-shaped third molded product. A diameter-expanding step as product 13;
(E) As shown in FIG. 2 (f), a flange forming step of forming the rim mounting flange 32 by drawing or ironing a portion to be the rim mounting flange 32;
And processing is performed in the order of this process.

上記（ａ）の工程（円筒状素材作成工程）について
（ａ−１）矩形材４は、図１（ｃ）〜図１（ｅ）に示すように、筒状に巻かれ、巻いた両端部を互いに突き合わせてフラッシュバット溶接、バット溶接、アーク溶接等で溶接接合し、溶接部５の盛り上がりとバリをトリミングして、円筒状素材６に作成される。
（ａ−２）円筒状素材６は、等厚であり、全周にわたって連続している。
（ａ−３）円筒状素材作成工程では、図示はしないが、パイプ状素材を所定寸法長さに切断して円筒状素材６を作成してもよい。 Regarding the step (a) (cylindrical material creation step) (a-1) The rectangular material 4 is wound into a cylindrical shape as shown in FIGS. Are joined to each other by flash butt welding, butt welding, arc welding, or the like, and the bulge and burrs of the welded portion 5 are trimmed to form the cylindrical material 6.
(A-2) The cylindrical material 6 is of equal thickness and is continuous over the entire circumference.
(A-3) In the cylindrical material creating step, although not shown, the cylindrical material 6 may be created by cutting the pipe-shaped material into a predetermined length.

上記（ｂ）の工程（口絞り工程）について
（ｂ−１）口絞り工程では、図２（ｂ）、図２（ｃ）に示すように、円筒状素材６の軸方向の一端６ａを口絞りして中央部に孔の開いた底部１１ａを有する円筒状の第１成形品１１を作成する。
（ｂ−２）口絞り工程では、円筒状素材６の軸方向の他端（一端６ａの軸方向反対側の端部）６ｂの直径を変化させずにまたはほとんど変化させずに第１成形品１１を作成する。
（ｂ−３）第１成形品１１は、ハブ取付け部２０となる底部１１ａと、底部１１ａの外周端部から第１成形品１１の軸方向に立ち上がる円筒部１１ｃと、を備える。 About the process (b) of the above (b) (b-1) In the baffle process, as shown in FIGS. 2 (b) and 2 (c), one end 6a in the axial direction of the cylindrical material 6 is opened. A cylindrical first molded product 11 having a bottom 11a having a hole in the center is drawn.
(B-2) In the squeezing step, the first molded product without changing or hardly changing the diameter of the other end 6b in the axial direction of the cylindrical material 6 (the end opposite to the end 6a in the axial direction) 6b. 11 is created.
(B-3) The 1st molded product 11 is provided with the bottom part 11a used as the hub attachment part 20, and the cylindrical part 11c which stands | starts up in the axial direction of the 1st molded product 11 from the outer peripheral edge part of the bottom part 11a.

（ｂ−４）第１成形品１１の円筒部１１ｃは、第１成形品１１の軸方向に延びている部分である。円筒部１１ｃは、第１成形品１１の軸方向と平行に円筒状に延びていてもよく、第１成形品１１の軸方向に対して傾斜して円錐状に延びていてもよい。
（ｂ−５）口絞り工程では、ハブ取付け部２０となる第１成形品１１の底部１１ａの面を平坦化するとともに、板厚を均一化するように、揺動鍛造を行なう。
（ｂ−６）口絞り工程では、図９に示すように、第１成形品１１の円筒部１１ｃの底部１１ａと反対側の円筒部１１ｃの開口端部１１ｄを除いて、第１成形品１１の円筒部１１ｃの板厚を薄くするように揺動鍛造を行なってもよい。開口端部１１ｄを除く理由は、開口端部１１ｄの加工硬化を抑制するためである。 (B-4) The cylindrical portion 11 c of the first molded product 11 is a portion extending in the axial direction of the first molded product 11. The cylindrical portion 11c may extend in a cylindrical shape parallel to the axial direction of the first molded product 11, or may extend in a conical shape inclined with respect to the axial direction of the first molded product 11.
(B-5) In the squeezing step, swing forging is performed so as to flatten the surface of the bottom 11a of the first molded product 11 serving as the hub mounting portion 20 and to equalize the plate thickness.
(B-6) In the squeezing step, as shown in FIG. 9, the first molded product 11 is removed except for the opening end portion 11 d of the cylindrical portion 11 c opposite to the bottom portion 11 a of the cylindrical portion 11 c of the first molded product 11. Oscillating forging may be performed so as to reduce the plate thickness of the cylindrical portion 11c. The reason for excluding the opening end portion 11d is to suppress work hardening of the opening end portion 11d.

（ｂ−７）口絞り工程では、図２（ｂ）、図２（ｃ）に示すように、上型４０が下型４１に対して揺動可回転能な一対の上下型４０，４１の下型４１上に円筒状素材６を載せ、上下型４０，４１を相対接近させながら上型４０を下型４１の軸芯４１ａに対して揺動回転運動させて、円筒状素材６を一端口絞りして、底部１１ａを平滑に所定の厚みに等厚（ほぼ等厚を含む）に成形して有底環状の第１成形品１１を作成する。
（ｂ−８）上型４０の軸芯４０ａは、図３、図４に示すように、下型４１の軸芯４１ａに対して所定角度αだけ傾けられているとともに上型４０の軸芯４０ａが下型４１の軸芯４１ａまわりに揺動回転するようになっている。
（ｂ−９）口絞り工程では、円筒状素材６が下型４１上に固定しないで載せられた状態で、下型４１を上昇させて上型４０に接近させて（または上型４０を下降させて下型４１に接近させて）円筒状素材６に軸方向に圧縮力をかけつつ、上型４０の軸芯４０ａが下型４１の軸芯４１ａまわりに揺動回転するように上型４０を揺動させて円筒状素材６を第１成形品１１に成形する。 (B-7) In the squeezing step, as shown in FIGS. 2 (b) and 2 (c), a pair of upper and lower dies 40, 41 in which the upper die 40 is swingable and rotatable with respect to the lower die 41 are used. The cylindrical material 6 is placed on the lower mold 41, and the upper mold 40 is swung and rotated with respect to the shaft core 41a of the lower mold 41 while the upper and lower molds 40 and 41 are relatively close to each other. The bottom portion 11a is smoothed and formed to have a predetermined thickness and a uniform thickness (including substantially the same thickness), thereby creating a bottomed annular first molded product 11.
(B-8) As shown in FIGS. 3 and 4, the axis 40 a of the upper mold 40 is inclined by a predetermined angle α with respect to the axis 41 a of the lower mold 41 and the axis 40 a of the upper mold 40. Oscillates and rotates around the axis 41a of the lower mold 41.
(B-9) In the squeezing step, with the cylindrical material 6 placed on the lower die 41 without being fixed, the lower die 41 is raised to approach the upper die 40 (or the upper die 40 is lowered). The upper die 40 so that the axial core 40a of the upper die 40 swings and rotates around the axial core 41a of the lower die 41 while applying a compressive force in the axial direction to the cylindrical material 6 (approaching the lower die 41). And the cylindrical material 6 is formed into the first molded product 11.

（ｂ−１０）揺動鍛造は、１回（１段）に限らず、型交換を含めて複数回行なってもよい。図２（ｂ）、図２（ｃ）では型交換を含めて２回行なわれる場合を示している。
（ｂ−１１）口絞り工程は、揺動鍛造を行なう前に、図１０に示すように、パンチ４２とダイ４３とを図示略のプレス機に組付けたプレス装置４４を用いて（プレスにて）予成形を行いハブ取付け部２０となる部分を内径側に曲げる工程を有していてもよい。 (B-10) Oscillating forging is not limited to once (one stage), and may be performed a plurality of times including die replacement. FIGS. 2B and 2C show a case where the process is performed twice including mold exchange.
(B-11) The squeezing process is performed using a press device 44 in which a punch 42 and a die 43 are assembled to a press machine (not shown) as shown in FIG. And a step of performing preforming and bending the portion to be the hub mounting portion 20 to the inner diameter side.

上記（ｃ）の工程（しごき工程）について
（ｃ−１）しごき工程は、ホイールディスク１０の円錐状部３１となる部分を薄肉化するための工程である。
（ｃ−２）しごき工程は、図２（ｄ）、図５に示すように、第１成形品１１の円筒部１１ｃの少なくとも一部をしごき加工して、第１成形品１１の円筒部１１ｃを不等厚に成形する工程である。
（ｃ−３）しごき工程では、第１成形品１１の底部１１ａの板厚を変化させずに第２成形品１２を作成する。
（ｃ−４）しごき工程は、プレスによって全周同時に行なわれる。しごき加工は、１回に限らず、型交換を含めて複数回行なってもよい。 Regarding the step (c) (squeezing step), the (c-1) ironing step is a step for thinning the portion to be the conical portion 31 of the wheel disk 10.
(C-2) In the ironing step, as shown in FIGS. 2D and 5, at least a part of the cylindrical portion 11 c of the first molded product 11 is ironed to form the cylindrical portion 11 c of the first molded product 11. Is a process of forming the unequal thickness.
(C-3) In the ironing step, the second molded product 12 is created without changing the plate thickness of the bottom 11a of the first molded product 11.
(C-4) The ironing process is simultaneously performed all around by pressing. The ironing process is not limited to one time, and may be performed a plurality of times including mold replacement.

（ｃ−５）しごき工程では、図５に示すように、パンチ５１とダイ５２とを図示略のプレス機に組付けたしごき装置５０を用いてしごき加工を行なう。しごき装置５０は、ワーク押え５３およびワーク支持具５４を有し、しごき加工をする前にワーク押え５３により第１成形品の底部１１ａ（第２成形品の底部１２ａ）を押え、しごき加工中にワークがずれないように固定する。ワーク押え５３で第１成形品の底部１１ａを押えたままの状態でパンチ５１を軸方向に動かしてしごき加工をする。また、ワーク支持具５４は開口端１１ｄ（１２ｄ）を支えることが好ましい。また、しごき加工した後にパンチ５１の方向にワーク支持具５４を動かして、しごき加工された第２成形品１２をダイ５２から押し出す機能を有する。
パンチ５１は、周方向に連続した環状（円筒状）をしており、パンチ５１の内周側面の径方向内側に突出する突出部５１ａを有し、突出部５１ａで第１成形品１１の円筒部１１ｃをしごく。
円柱状であるダイ５２の、パンチ５１の突出部５１ａに対向する側の側面が、凹凸面５２ａとされている。凹凸面５２ａは、パンチ５１の突出部５１ａとの径方向の間隔が一様でなく異なる部分がある面である。ただし、凹凸面５２ａは、一様な面であってもよい。また、凹凸面５２ａは、パンチ５１の突出部５１ａとの径方向の間隔が徐々に（なだらかに）狭くなる（または広くなる）面であってもよい。ダイ５２の凹凸面５２ａは、パンチ５１の突出部５１ａに対向する側の側面とパンチ５１の突出部５１ａとの間隔を一定厚の第１成形品１１の円筒部１１ｃの板厚より狭くするために、ダイ５２の側面の軸方向および／または周方向で、隣接する部分（凹部５２ｂ）に比べてパンチ５１の突出部５１ａ側に凸となる凸部５２ｃが少なくとも１つ設けられることにより形成されている。ダイ５２の凹凸面５２ａは、パンチ５１の突出部５１ａに対向する側の側面とパンチ５１の突出部５１ａとの間隔を一定厚の第１成形品１１の円筒部１１ｃの板厚より狭くするために、ダイ５２の側面の周方向で、隣接する部分（凹部５２ｂ）に比べてパンチ５１の突出部５１ａ側に凸となる凸部５２ｃが少なくとも１つ設けられることにより形成されていてもよい。凸部５２ｃの突出量は、１つの凸部５２ｃの中で一定とされていてもよく異なっていてもよい。また、複数の凸部５２ｃが設けられる場合、それぞれの凸部５２ｃの突出量は同一であってもよく異なっていてもよい。凸部５２ｃは、ダイ５２のパンチの突出部５１ａに対向する側の側面の少なくとも一部に形成されていてもよい。
ダイ５２の側面の軸方向で、１つの凸部５２ｃと、その１つの凸部５２ｃに隣接する凹部５２ｂとは、傾斜面５２ｄで接続されている。傾斜面５２ｄの、ダイ５２の側面の軸方向に対する角度は、６０度以下に緩やかにされていることが望ましく、さらには４５度以下に緩やかにされていることが望ましい。各傾斜面５２ｄの傾斜角度は、一定であってもよく、徐々に変化していてもよい。 (C-5) In the ironing process, as shown in FIG. 5, ironing is performed using an ironing device 50 in which a punch 51 and a die 52 are assembled to a press machine (not shown). The ironing device 50 includes a work presser 53 and a work support 54, and presses the bottom 11a of the first molded product (the bottom 12a of the second molded product) with the work presser 53 before performing the ironing process. Fix so that the workpiece does not slip. Ironing is performed by moving the punch 51 in the axial direction while holding the bottom 11a of the first molded product with the work holder 53. The work support 54 preferably supports the opening end 11d (12d). Further, after the ironing process, the workpiece support 54 is moved in the direction of the punch 51, and the second molded product 12 subjected to the ironing process is pushed out from the die 52.
The punch 51 has an annular shape (cylindrical shape) that is continuous in the circumferential direction, and has a protruding portion 51 a that protrudes radially inward of the inner peripheral side surface of the punch 51, and the cylindrical portion of the first molded product 11 at the protruding portion 51 a. Squeeze the part 11c.
The side surface of the cylindrical die 52 facing the protruding portion 51a of the punch 51 is an uneven surface 52a. The concavo-convex surface 52a is a surface in which the radial distance from the protruding portion 51a of the punch 51 is not uniform but has a different portion. However, the uneven surface 52a may be a uniform surface. Further, the uneven surface 52a may be a surface in which the radial distance from the projecting portion 51a of the punch 51 gradually (slowly) narrows (or widens). The concave / convex surface 52a of the die 52 is for making the distance between the side surface of the punch 51 facing the protruding portion 51a and the protruding portion 51a of the punch 51 narrower than the plate thickness of the cylindrical portion 11c of the first molded product 11 having a certain thickness. In addition, in the axial direction and / or the circumferential direction of the side surface of the die 52, it is formed by providing at least one convex portion 52c that is convex on the protruding portion 51a side of the punch 51 as compared to the adjacent portion (concave portion 52b). ing. The concave / convex surface 52a of the die 52 is for making the distance between the side surface of the punch 51 facing the protruding portion 51a and the protruding portion 51a of the punch 51 narrower than the plate thickness of the cylindrical portion 11c of the first molded product 11 having a certain thickness. In addition, in the circumferential direction of the side surface of the die 52, it may be formed by providing at least one convex portion 52c that is convex on the protruding portion 51a side of the punch 51 as compared to the adjacent portion (concave portion 52b). The protruding amount of the convex portion 52c may be constant or different in one convex portion 52c. Moreover, when the some convex part 52c is provided, the protrusion amount of each convex part 52c may be the same, and may differ. The convex portion 52c may be formed on at least a part of the side surface of the die 52 facing the protruding portion 51a of the punch.
In the axial direction of the side surface of the die 52, one convex portion 52c and the concave portion 52b adjacent to the one convex portion 52c are connected by an inclined surface 52d. The angle of the inclined surface 52d with respect to the axial direction of the side surface of the die 52 is preferably moderated to 60 degrees or less, and more desirably 45 degrees or less. The inclination angle of each inclined surface 52d may be constant or may change gradually.

（ｃ−６）パンチ５１がアウターパンチからなり、ダイ５２がパンチ５１の内周側部分に対して、軸方向に出入りするインナーダイからなる。ダイ５２の外周側面が凹凸面５２ａとされている。アウターパンチ５１とインナーダイ５２を用いてしごき加工を行なうことで、第２成形品１２の円筒部分１２ｃの内径側のみに凹凸面５２ａに対応する不等厚形状を得る。
（ｃ−７）しごき工程では、パンチ５１をダイ５２に対して第１成形品１１の円筒部１１ｃの軸方向（ホイールディスク１０の軸方向と同方向）にのみ相対動させてしごき加工する。なお、図２（ｄ）、図５において、Ａ１は、パンチ５１の加工方向である。なお、パンチ５１とダイ５２との上下関係は、図２（ｄ）、図５に示す上下関係と反対になっていてもよい。 (C-6) The punch 51 is composed of an outer punch, and the die 52 is composed of an inner die that moves in and out in the axial direction with respect to the inner peripheral side portion of the punch 51. The outer peripheral side surface of the die 52 is an uneven surface 52a. By performing ironing using the outer punch 51 and the inner die 52, an unequal thickness shape corresponding to the uneven surface 52a is obtained only on the inner diameter side of the cylindrical portion 12c of the second molded product 12.
(C-7) In the ironing step, ironing is performed by moving the punch 51 relative to the die 52 only in the axial direction of the cylindrical portion 11c of the first molded product 11 (the same direction as the axial direction of the wheel disk 10). In FIG. 2D and FIG. 5, A1 is the processing direction of the punch 51. The vertical relationship between the punch 51 and the die 52 may be opposite to the vertical relationship shown in FIGS.

（ｃ−８）しごき工程では、第１成形品１１の円筒部１１ｃの開口端部１１ｄ側はしごき加工をしないかしごき率を１０％以下にしごき加工することにより成形して不等厚有底環状の第２成形品１２を作成する。円筒部１１ｃの開後端部１１ｄ側をしごき加工しないかしごき率を１０％以下にしごき加工する理由は、円筒部１１ｃの開口端部１１ｄの加工硬化を抑制して拡径工程（上記（ｄ）の工程）で拡径した部分に材料割れが発生することを抑制するためである。
図１１は、引張強さが５９０Ｍｐａ材、３７０Ｍｐａ材、４４０Ｍｐａ材を用いて２２．５インチホイール用のホイールディスク（大中型ホイールディスク）１０を試作した場合の、しごき工程における円筒部１１ｃの開口端部１１ｄ側のしごき率と拡径工程で発生する拡径部分の割れとの関係を示す表である。図１１から、つぎの（ｉ）〜（ｉｉｉ）がわかる。（ｉ）しごき率が１０％以下では割れが発生しない。（ｉｉ）しごき率が１０％より大になると割れが発生する。（ｉｉｉ）よって、（ｉ）、（ｉｉ）より、しごき率が１０％以下が望ましい。 (C-8) In the ironing step, the opening end 11d side of the cylindrical portion 11c of the first molded product 11 is formed by ironing so that the ironing ratio is 10% or less without ironing. An annular second molded product 12 is created. The reason why the ironing ratio of the cylindrical portion 11c that does not iron the opened end portion 11d is 10% or less is that the diameter is increased by suppressing the work hardening of the opening end portion 11d of the cylindrical portion 11c (the above (d This is to suppress the occurrence of material cracks in the portion expanded in the step).
FIG. 11 shows the open end of the cylindrical portion 11c in the ironing process when a wheel disc (large and medium type wheel disc) 10 for a 22.5 inch wheel is manufactured using a tensile strength of 590 Mpa material, 370 Mpa material, and 440 Mpa material. It is a table | surface which shows the relationship between the ironing rate by the side of the part 11d, and the crack of the enlarged diameter part which generate | occur | produces at an enlarged diameter process. From FIG. 11, the following (i) to (iii) are known. (I) No cracking occurs when the ironing rate is 10% or less. (Ii) Cracking occurs when the ironing rate exceeds 10%. (Iii) Therefore, the ironing rate is preferably 10% or less from (i) and (ii).

上記（ｄ）の工程（拡径工程）について
（ｄ−１）拡径工程では、図２（ｅ）、図６に示すように、第２成形品１２の全周にわたって連続する円筒部分１２ｃの開口側を拡径する。
（ｄ−２）拡径工程では、円錐状（略円錐状を含む）の部位を有する拡径用パンチ６１を第２成形品１２に押し込むことで円筒部分１２ｃの開口端１２ｄを円筒部分１２ｃの底部１２ａ側より大きく拡径加工を行なう。
（ｄ−３）拡径工程では、拡径用パンチ６１と拡径用ダイ６２とを図示略のプレス機に組付けた拡径装置６０を用いて拡径加工を行なう。 Regarding the step (d) (diameter expanding step) (d-1) In the diameter expanding step, as shown in FIGS. 2 (e) and 6, the cylindrical portion 12c continuous over the entire circumference of the second molded product 12 is formed. The opening side is enlarged.
(D-2) In the diameter expansion step, the diameter-expansion punch 61 having a conical portion (including a substantially conical shape) is pushed into the second molded product 12 so that the opening end 12d of the cylindrical portion 12c is moved to the cylindrical portion 12c. A diameter expansion process is performed larger than the bottom 12a side.
(D-3) In the diameter expansion step, the diameter expansion process is performed using a diameter expansion device 60 in which the diameter expansion punch 61 and the diameter expansion die 62 are assembled to a press machine (not shown).

（ｄ−４）拡径工程では、拡径用パンチ６１を拡径用ダイ６２に対して第２成形品１２の円筒部分１２ｃの軸方向（ホイールディスク１０の軸方向と同方向）に相対動させて拡径加工する。なお、図２（ｅ）、図６において、Ａ２は、拡径用パンチ６１の加工方向である。なお、拡径用パンチ６１と拡径用ダイ６２との上下関係は、図２（ｅ）、図６に示す上下関係と反対になっていてもよい。
（ｄ−５）拡径用ダイ６２が円錐状穴６２ａをもつアウターダイからなる。また、拡径用パンチ６１が拡径用ダイ６２の円錐状穴６２ａに円錐状穴６２ａの軸方向（ホイールディスク１０の軸方向と同方向）に出入りするインナーパンチからなる。拡径用ダイ６２は、円錐状穴６２ａがなく、平板部６２ｂのみでもよい。 (D-4) In the diameter expanding step, the diameter increasing punch 61 is moved relative to the diameter expanding die 62 in the axial direction of the cylindrical portion 12c of the second molded product 12 (the same direction as the axial direction of the wheel disk 10). To increase the diameter. In FIG. 2 (e) and FIG. 6, A 2 is the processing direction of the diameter-expansion punch 61. Note that the vertical relationship between the diameter-expansion punch 61 and the diameter-expansion die 62 may be opposite to the vertical relationship shown in FIGS.
(D-5) The diameter expansion die 62 is an outer die having a conical hole 62a. The diameter-expansion punch 61 is an inner punch that enters and exits the conical hole 62a of the diameter-expansion die 62 in the axial direction of the conical hole 62a (the same direction as the axial direction of the wheel disk 10). The diameter-expanding die 62 does not have the conical hole 62a but may be only the flat plate portion 62b.

（ｄ−６）拡径工程では、拡径用パンチ６１にて鍛造成形して、しごき工程（上記（ｃ）の工程）で内径側に付与されていた凹凸形状を外径側へと押し出してもよい。これにより、狙いとする形状と板厚分布を得ることができる。ただし、拡径用パンチ６１にて鍛造成形する代わりに、図２（ｆ）、図７に示すように、フランジ成形工程（上記（ｅ）の工程）にてパンチ７１にて鍛造成形してもよい。また、図８に示すように、拡径工程（上記（ｄ）の工程）後であってフランジ成形工程（上記（ｅ）の工程）前にパンチ８１のストロークエンドにて鍛造成形してもよい。なお、図８において、Ａ３は、パンチ８１の加工方向である。 (D-6) In the diameter expansion process, forging is performed with the diameter expansion punch 61, and the uneven shape imparted to the inner diameter side in the ironing process (step (c) above) is pushed out to the outer diameter side. Also good. Thereby, the target shape and plate thickness distribution can be obtained. However, instead of forging with the diameter expanding punch 61, as shown in FIGS. 2 (f) and 7, forging with the punch 71 in the flange forming step (step (e) above). Good. Further, as shown in FIG. 8, forging may be performed at the stroke end of the punch 81 after the diameter expanding step (step (d) above) and before the flange forming step (step (e) above). . In FIG. 8, A3 is the processing direction of the punch 81.

（ｄ−７）拡径工程は、プレスによって全周同時に行なわれることが望ましい。
（ｄ−８）拡径工程の加工方法は、上記に限らず、図示略のエキスパンダー等を用いた加工方法であってもよい。 (D-7) It is desirable that the diameter expansion step is performed simultaneously all around by pressing.
(D-8) The processing method of the diameter expansion process is not limited to the above, and may be a processing method using an expander (not shown) or the like.

上記（ｅ）の工程（フランジ成形工程）について
（ｅ−１）フランジ成形工程は、ホイール１０のリムと接続する取付けフランジ３２を成形する工程である。フランジ成形工程は、図２（ｆ）、図７に示すように、絞り加工を行なう工程である。ただし、絞り加工としごき加工を同時に行なってもよい。しごき加工のみでもよい。
（ｅ−２）フランジ成形工程では、第３成形品１３の円錐部１３ｃの開口端部１３ｄ（リム取付けフランジ３２となる部分）を絞り加工またはしごき絞り加工して、リム取付けフランジ３２を成形する。フランジ成形工程では、第３成形品１３の円錐部１３ｃの開口端部１３ｄをしごき加工して立ち上げ、狙いとする外径と板厚を得る。
（ｅ−３）フランジ成形工程では、パンチ７１とダイ７２とを図示略のプレス機に組付けたフランジ成形装置７０を用いて加工を行なう。 Regarding Step (e) (Flange Forming Step) (e-1) The flange forming step is a step of forming the mounting flange 32 connected to the rim of the wheel 10. The flange forming step is a step of drawing as shown in FIGS. However, drawing and ironing may be performed simultaneously. Only ironing may be used.
(E-2) In the flange forming process, the rim mounting flange 32 is formed by drawing or squeezing the opening end portion 13d (the portion to be the rim mounting flange 32) of the conical portion 13c of the third molded product 13. . In the flange forming step, the open end 13d of the conical portion 13c of the third molded product 13 is ironed and started up to obtain a target outer diameter and plate thickness.
(E-3) In the flange forming step, processing is performed using a flange forming apparatus 70 in which the punch 71 and the die 72 are assembled to a press machine (not shown).

（ｅ−４）ダイ７２が、開口部付近が筒状とされた穴７２ａをもつアウターダイからなる。また、パンチ７１が、アウターダイ７２の穴７２ａに該穴７２ａの軸方向（ホイールディスク１０の軸方向と同方向）に出入りするインナーパンチ７１からなる。
（ｅ−５）ダイ７２は、穴７２ａの開口端部７２ｂで、第３成形品１３の円錐部１３ｃの開口端部１３ｄをしごく。
（ｅ−６）フランジ成形工程は、プレスによって全周同時に行なわれる。 (E-4) The die 72 is an outer die having a hole 72a in which the vicinity of the opening is cylindrical. The punch 71 includes an inner punch 71 that enters and exits the hole 72a of the outer die 72 in the axial direction of the hole 72a (the same direction as the axial direction of the wheel disk 10).
(E-5) The die 72 squeezes the opening end portion 13d of the conical portion 13c of the third molded product 13 at the opening end portion 72b of the hole 72a.
(E-6) The flange forming step is simultaneously performed all around by pressing.

（ｅ−７）フランジ成形工程では、パンチ７１をダイ７２に対して第３成形品１３の円錐部１３ｃの軸方向（ホイールディスク１０の軸方向と同方向）にのみ相対動させて加工する。なお、図２（ｆ）、図７において、Ａ４は、パンチ７１の加工方向である。なお、パンチ７１とダイ７２との上下関係は、図２（ｆ）、図７に示す上下関係と反対になっていてもよい。
（ｅ−８）フランジ成形工程の加工方法は、プレスによる絞り加工に限定されず、たとえばフローフォーミング（スピニング）等であってもよい。
（ｅ−９）フランジ成形工程では、プレスによる絞り加工（またはフローフォーミング等）の後に、寸法出しのため機械加工を施してもよい。
（ｅ−１０）フランジ成形工程の加工（リム取付けフランジ３２を成形する加工）は、拡径工程（上記（ｄ）の工程）で行なわれていてもよい。
（ｅ−１１）フランジ成形工程の加工方法は、機械加工のみであってもよい。 (E-7) In the flange forming step, the punch 71 is processed by moving relative to the die 72 only in the axial direction of the conical portion 13c of the third molded product 13 (the same direction as the axial direction of the wheel disk 10). In FIG. 2 (f) and FIG. 7, A4 is the processing direction of the punch 71. Note that the vertical relationship between the punch 71 and the die 72 may be opposite to the vertical relationship shown in FIG.
(E-8) The processing method in the flange forming step is not limited to drawing by a press, and may be, for example, flow forming (spinning).
(E-9) In the flange forming step, machining may be performed for dimensioning after drawing (or flow forming, etc.) by pressing.
(E-10) The processing of the flange forming step (processing of forming the rim mounting flange 32) may be performed in the diameter expansion step (step (d) above).
(E-11) The machining method in the flange forming step may be only machining.

ホイールディスク１０は、図１２に示すように、ハブ取付けボルト穴２２、飾り穴３３を打ち抜き、製造される。 As shown in FIG. 12, the wheel disc 10 is manufactured by punching the hub mounting bolt hole 22 and the decorative hole 33.

つぎに、本発明実施例の効果を説明する。
第１成形品１１の円筒部１１ｃの少なくとも一部をしごき加工して不等厚有底環状の第２成形品１２を作成するしごき工程を有するため、スピニング加工を無くすことができる。 Next, effects of the embodiment of the present invention will be described.
Since there is an ironing step in which at least a part of the cylindrical portion 11c of the first molded product 11 is ironed to create an unequal-thickness bottomed annular second molded product 12, the spinning process can be eliminated.

しごき工程では円筒部１１ｃの開口端部１１ｄ側はしごき加工をしないかしごき率を１０％以下にしごき加工するため、円筒部１１ｃの開口端部１１ｄ側の加工硬化を抑制できる。そのため、しごき工程の後の拡径工程で拡径した部分の材料が割れることを抑制できる。 In the ironing process, the opening end 11d side of the cylindrical portion 11c is ironed at a squeezing rate of 10% or less, so that work hardening on the opening end 11d side of the cylindrical portion 11c can be suppressed. Therefore, it can suppress that the material of the part expanded in the diameter expansion process after an ironing process cracks.

口絞り工程では揺動鍛造が行なわれるため、プレス成形ではできない精度でハブ取付け部２０となる底部１１ａを平滑等厚に成形できる。そのため、ハブ取付け部２０となる底部１１ａ（１２ａ、１３ａ）の機械加工を不要とすることができる。 Since swing forging is performed in the squeezing process, the bottom 11a that becomes the hub mounting portion 20 can be formed with a smooth and uniform thickness with an accuracy that cannot be achieved by press molding. Therefore, machining of the bottom 11a (12a, 13a) to be the hub attachment portion 20 can be made unnecessary.

円筒状素材６の一端６ａを口絞りして有底環状の第１成形品１１を作成する口絞り工程では、円筒状素材６の他端６ｂの直径を変化させずに第１成形品１１を作成するため、円筒状素材６の他端６ｂの加工硬化を抑制できる。そのため、拡径工程で材料が割れることを抑制できる。 In the squeezing step in which one end 6a of the cylindrical material 6 is squeezed to create the bottomed annular first molded product 11, the first molded product 11 is removed without changing the diameter of the other end 6b of the cylindrical material 6. Since it produces, the work hardening of the other end 6b of the cylindrical raw material 6 can be suppressed. Therefore, it can suppress that a material breaks at a diameter expansion process.

拡径工程では、拡径用パンチ６１のストロークエンドにて鍛造成形してしごき工程で内径側にのみ付与されていた凹凸形状を外径側へと押し出すため、ホイールを車両に搭載する際にホイールディスク１０がブレーキと干渉することを抑制できる。 In the diameter expansion process, the fork is formed at the stroke end of the diameter expansion punch 61 and the uneven shape imparted only to the inner diameter side in the ironing process is pushed out to the outer diameter side. It is possible to suppress the disc 10 from interfering with the brake.

拡径工程の後にフランジ成形工程を有するため、精度の良いリム取付けフランジ３２を得ることができる。 Since the flange forming step is provided after the diameter expanding step, the rim mounting flange 32 with high accuracy can be obtained.

口絞り工程では第１成形品１１の円筒部１１ｃの板厚を薄くするように揺動鍛造を行なう場合、しごき工程において第１成形品１１の円筒部１１ｃをしごく量を減らすことができる。そのため、しごき工程でしごき加工を容易に行なうことができる。 In the squeezing process, when swing forging is performed so as to reduce the thickness of the cylindrical portion 11c of the first molded product 11, the amount of the cylindrical portion 11c of the first molded product 11 can be reduced in the ironing process. Therefore, the ironing process can be easily performed in the ironing process.

口絞り工程では、プレスにて予成形を行いハブ取付け部２０となる部分を内径側に曲げた後に、揺動鍛造を行い第１成形品１１を作成することにより、予成形を行わない場合に比べて揺動鍛造を容易に行なうことができる。 In the squeezing step, when preforming is performed by pressing and bending the portion to be the hub mounting portion 20 to the inner diameter side, and then performing the swing forging to create the first molded product 11, the preforming is not performed. In comparison, swing forging can be performed easily.

しごき工程ではしごき加工によって第２成形品１２が成形されるため、スピニングによって第２成形品１２が成形される場合に比べて、つぎの利点を有する。
１．加工時間が短い。そのため、ホイールディスク１０の生産性が高い。
２．第２成形品１２、第３成形品１３、さらにはホイールディスク１０の表面にスピニング加工の加工ロールの成形痕が残ることを抑制できる。
３．ワーク端部寸法のバラツキを小さくでき、加工後に端部を切断する必要がない。そのため、材料が低減できる。また、加工硬化したワーク端部を切断するのに用いられる刃工具の破損のおそれも抑制できる。 Since the second molded product 12 is formed by ironing in the ironing process, it has the following advantages over the case where the second molded product 12 is molded by spinning.
1. Processing time is short. Therefore, the productivity of the wheel disc 10 is high.
2. It is possible to suppress the formation traces of the processing rolls for spinning processing remaining on the surfaces of the second molded product 12, the third molded product 13, and the wheel disk 10.
3. Variations in the dimensions of the workpiece end can be reduced, and there is no need to cut the end after machining. Therefore, the material can be reduced. In addition, the risk of breakage of the blade tool used to cut the work-hardened workpiece end can be suppressed.

２ディスク素材
４矩形材
５溶接部
６円筒状素材
６ａ円筒状素材の一端
６ｂ円筒状素材の他端
１０ホイールディスク
１１第１成形品
１１ａ第１成形品の底部
１１ｂ第１成形品の孔
１１ｃ第１成形品の円筒部
１１ｄ第１成形品の開口端部
１２第２成形品
１２ａ第２成形品の底部
１２ｃ第２成形品の円筒部分
１３第３成形品
１３ｃ第３成形品の円錐部
１３ｄ第３成形品の開口端部
２０ハブ取付け部
２１ハブ穴
２２ハブ取付けボルト穴
３０立ち上がり部
３１円錐状部
３２リム取付けフランジ
３３飾り穴
４０上型
４０ａ上型の軸芯
４１下型
４１ａ下型の軸芯
４２パンチ
４３ダイ
４４プレス装置
５０しごき装置
５１しごき装置のパンチ
５１ａ突出部
５２しごき装置のダイ
５２ａ凹凸面
５２ｂ凹部
５２ｃ凸部
５２ｄ傾斜面
６０拡径装置
６１拡径用パンチ
６２拡径用ダイ
７０フランジ成形装置
７１フランジ成形装置のパンチ
７２フランジ成形装置のダイ 2 Disc material 4 Rectangular material 5 Welded portion 6 Cylindrical material 6a One end 6b of the cylindrical material 10 Other end 10 of the cylindrical material Wheel disc 11 First molded product 11a First molded product bottom 11b First molded product hole 11c First Cylindrical portion 11d of the first molded product Third cylindrical portion 11d of the first molded product Third cylindrical portion 13d of the second molded product 13c 3 Open end 20 of molded product Hub attachment portion 21 Hub hole 22 Hub attachment bolt hole 30 Standing portion 31 Conical portion 32 Rim attachment flange 33 Decoration hole 40 Upper die 40a Upper die core 41 Lower die 41a Lower die shaft Core 42 Punch 43 Die 44 Press device 50 Ironing device 51 Ironing device punch 51a Protrusion 52 Ironing device die 52a Concave surface 52b Concavity 52c Convex portion 52d Inclined surface 60 For diameter 61 diameter punch 62 diameter die 70 flange forming apparatus 71 die punch 72 flanging device flanging device

Claims

A cylindrical material creating step of cutting a plate material to create a rectangular material, rounding the rectangular material and butt welding both ends, and creating a cylindrical material;
A cylindrical first molded product having a disk-shaped bottom part with a hole in the center part obtained by narrowing one end of the cylindrical material and molding a part to be a hub mounting part to have an almost equal thickness is prepared. A mouth-squeezing process,
An ironing step of ironing at least a part of the cylindrical portion of the first molded product with a punch and an ironing device having a die to produce an annular second molded product with an unequal thickness;
Expanding the cylindrical portion of the second molded product to make the cylindrical portion conical, and increasing the diameter of the disc,
A method for manufacturing a wheel disc for a vehicle, comprising:

In the ironing step, the first molded product is formed by ironing with an ironing device so that the ironing ratio of the first molded product on the opening end side of the cylindrical portion is not ironed to 10% or less. The method for manufacturing a wheel disk for a vehicle according to claim 1, further comprising the step of creating the second molded product having an unequal thickness and an annular shape.

In the mouth-squeezing step, the upper die is swung with respect to the lower die shaft while the pair of upper and lower dies are relatively approached, and the cylindrical material is squeezed at one end, and the portion that becomes the hub attachment portion is subsequently The method for manufacturing a wheel disc for a vehicle according to claim 1, further comprising a step of forming the first molded product by forming the first molded product smoothly to a predetermined thickness without processing.

The first molded product is created without changing the diameter of the other end of the cylindrical material in the mouth-squeezing step of creating the first molded product by squeezing one end of the cylindrical material. The method for manufacturing a wheel disc for a vehicle according to any one of claims 3 to 4.

In the said diameter expansion process, while expanding the cylindrical part of the said 2nd molded product, the uneven | corrugated shape provided to the internal diameter side by the said ironing process is extruded to the outer diameter side. The manufacturing method of the wheel disc for vehicles of any one of Claims 1.

After the diameter expansion step,
The method for manufacturing a wheel disc for a vehicle according to any one of claims 1 to 5, further comprising a flange forming step of forming a rim mounting flange by drawing or ironing a portion to be a rim mounting flange. .

7. The swing forging is performed according to any one of claims 1 to 6, wherein in the squeezing step, swing forging is performed so that a portion of the first molded product to be a hub attachment portion is planarized and the plate thickness is made uniform. A method for manufacturing a wheel disc for a vehicle.

8. The manufacture of a wheel disc for a vehicle according to claim 1, wherein in the aperture drawing step, swing forging is performed so as to reduce a plate thickness of the cylindrical portion of the first molded product. Method.

9. The method according to claim 1, wherein the mouth-drawing step includes preforming with a press and bending a portion to be a hub attachment portion toward an inner diameter side, and then performing swing forging to create the first molded product. A method for manufacturing a wheel disc for a vehicle according to claim 1.