JPH07275987A - Rotary forging device and production of automobile wheel using above - Google Patents

Abstract

PURPOSE:To improve both forming precisions of an opening end part of the upper side of a rim and a peripheral part of a disk by oppositely approaching an upper die and a lower die while synchronously rotating these dies, separating the raw material projecting from this range of pressing down to the upper and lower sides with a pressing roller and forming the rim. CONSTITUTION:A projecting raw material grows upward from a boundary part between a pressing roller 4 and a drum lower part 311 of an upper die 301. In this time, an auxiliary die 303 is fit outside on a small diameter drum part 321 of the upper die 301, some clearance is formed between the lower end of this auxiliary die 303 and the drum lower part 311, but the generating line in the pressing roller side of the rim forming surface of the auxiliary die 303 is composed so as to continue on the extending line of the generating line of the pressing roller 4 side in the outer circumference surface of the drum lower part 311. On this result, the raw material passes over the clearance and transfers on the rim forming surface. After then, the raw material grows in a state of its internal circumference surface being aligned with the rim forming surface over all the circumference. Then, finally, the raw material grown upward and downward is formed into the rim 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary forging device for producing a disc with a rim in which a cylindrical rim is continuously provided on the periphery of the disc, and a method for producing an automobile wheel using this device.

[0002]

2. Description of the Related Art A rotary forging device for manufacturing a disc with a rim has already been proposed in Japanese Patent Application No. 5-281510. By using this, a disc (2) as shown in FIG. The rim (1) connected to the periphery of the is composed of a straight cylindrical first rim (11) protruding to one side and a second rim (12) having a similar shape protruding to the opposite side. It is possible to manufacture discs with rims of the following types.

The rotary forging device, as shown in FIG.
The lower surface of the upper die (301) and the upper surface of the lower die (302) are opposed to each other, and the lower surface of the upper die (301) is formed in an umbrella shape so that one of the busbars thereof is substantially horizontal ( The axis of (301) is inclined, and a cylindrical auxiliary mold (303) that is coaxial with the lower mold (302) is externally fitted to the upper mold (301). The auxiliary die (303) is provided with a rim forming surface on the outer body of the lower die (302), which is the same as the inner surface of the second rim (12). A rim molding surface is provided that matches the inner peripheral surface of the rim (11).

In this product, as shown in FIG. 1, the upper die (3
The thick disk-shaped work (10) is placed between the lower surface of (01) and the upper surface of the lower mold (302), and the upper mold (301) and the auxiliary mold (303) are rotated while these molds are synchronously rotated. ) In a synchronized manner, the work (10) is pressed down by the rotary forging action of the upper die (301) and the lower die (302), and the work (10)
The outer peripheral portion of the mold begins to project annularly from the mold boundary. At this time, a columnar pressure roller (4) which coincides with the outer peripheral surface from the end portion of the first rim (11) to a part of the second rim (12) is provided on the side of the mold boundary portion. Moreover, since the protruding material is positioned on the inclined side of the upper mold (301) with a predetermined interval, the protruding material reaches the surface of the pressure roller (4) and then, as shown in FIG. It will be separated into and grow in each direction. The material facing downward is molded on the first rim (11) in conformity with the molding cross section of the rim molding surface of the lower mold (302) and the pressure roller (4), and the material facing upward is auxiliary. Extruded from the boundary between the lower part of the mold (303) and the pressure roller (4),
It grows along the rim forming surface of the auxiliary mold (303) and finally becomes the second rim (12) (state of FIG. 3).

In the rotary forging apparatus using this auxiliary die (303), the inner peripheral surface of the material grows over the entire circumference of the rim forming surface of the auxiliary die (303). It is possible to eliminate the deterioration of the molding accuracy of the open end portion of the disk (2), which is separated from the disk (2). However, with this device,
Since the auxiliary mold (303) is fitted on the lower part of the body of (301),
The peripheral edge of the disk (2) comes off the peripheral edge (rotational forging area) of the upper die (301), and there is a problem that the peripheral edge of the disk cannot be formed accurately. In order to solve this problem, the outer diameter of the lower part of the upper mold (301) is made to substantially match that of the upper end of the lower mold (302), and the auxiliary mold (303)
Although it is conceivable that the body of the body has a very thin wall, in this case, the strength of the body is insufficient, which is not practical. [Invention of Claim 1]

[0006]

[Technical Problem] The present invention has been made in view of the above-mentioned problems, and is described in "A substantially umbrella-shaped lower surface of an upper mold (301) and a lower mold (3
02) and the upper mold (301) so that one of the busbars of the lower surface of the upper mold (301) is substantially horizontal.
Inclining the axis of (01), the upper mold (301) is
2) A cylindrical rotatable auxiliary mold (303) coaxial with 2) is externally fitted, and the work (10) is interposed between the lower surface of the upper mold (301) and the upper surface of the lower mold (302). The upper mold (301) and the lower mold (302)
While rotating synchronously with and, these dies are made to face each other and the work (10) is pressed down, and the material protruding from this reduction area is arranged on the side of the mold boundary and on the inclined side of the upper mold (301). In the rotary forging device that separates the rim (1) from above and below by the pressure roller (4) to form the rim (1) that protrudes above and below the disk (2), the open end above the rim (1) disk
The task is to improve the molding accuracy of both the peripheral portions of (2).

[0007]

[Technical Means] The technical means of the present invention taken to solve the above-mentioned problem is that "the upper die (301) has a small-diameter body portion (321) above the lower body portion (311) continuous with the lower surface thereof. Is installed, and the auxiliary mold (303) is fitted on the small diameter body (321) with a margin,
The busbar on the pressure roller (4) side of the rim forming surface of the auxiliary mold (303) is made continuous with the extension line of the busbar on the pressure roller (4) side on the outer peripheral surface of the lower body (311). .

[0008]

The above technical means of the present invention operates as follows. In this product, the work (10) is interposed between the lower surface of the upper die (301) and the upper surface of the lower die (302), and the upper die (301) and the lower die (302) are rotated in synchronization with each other. When the molds are brought close to each other, the work (10) is pressed down by these rotary forging operations, and the outer peripheral part of the work (10) begins to project from the mold boundary part. After reaching the surface of the pressure roller (4), the protruding material is separated into upper and lower parts and grows in the respective directions.

The upper material is composed of a pressure roller (4) and an upper die (30
It grows upward from the boundary with the lower body (311) of 1). At this time, the auxiliary die (30
3) fits over the lower end of this auxiliary mold (303) and the lower torso (311)
A small gap is formed between the
The busbar on the pressure roller (4) side of the rim molding surface of 3) is the lower part of the body.
Since the outer peripheral surface of (311) is continuous on the extension line of the generating line on the pressure roller (4) side, the material is transferred to the rim forming surface beyond the gap. After that, the inner peripheral surface of the material grows in a state in which the inner peripheral surface of the material coincides with the entire surface of the rim. Finally, the material that has grown up and down is formed into the rim (1).

In this case, the rim (1) at the time of completion of molding
The open end above the rim is aligned with the rim molding surface over the entire circumference. In addition, the substantially umbrella-shaped lower surface of the upper die (301) is in contact with the peripheral portion of the disc (2).

[0011]

[Effects] The present invention having the above-described structure has the following unique effects. In this one, the open end above the rim (1)
Since the entire circumference is aligned with the rim molding surface of the auxiliary mold (303), the molding accuracy of this open end is improved.
Further, since the lower surface of the upper die (301) is in contact with the peripheral portion of the disc (2), the molding precision of the peripheral portion of the disc is improved. [Invention of claim 2] The invention of claim 2 is the rotary forging apparatus of the invention of claim 1 in which the disk
(2) A rim portion that projects upward from the rim portion has a flared shape in which the diameter increases toward the open end, so that it is possible to manufacture a disc with a rim, and technical means therefor are:
That is, the rim molding surface of the auxiliary mold (303) has a flare shape in which the diameter is enlarged upward.

In this case, since the rim forming surface of the auxiliary mold (303) has a flare shape in which the diameter is enlarged upward, it is directed upward from the boundary portion between the pressure roller (4) and the lower body portion (311). The material grows along the rim molding surface in a manner of expanding in diameter. Therefore, it is possible to manufacture a disc with a rim in which the rim portion protruding above the disc (2) has a flare shape in which the diameter increases toward the open end. [Invention of Claim 3] The invention of Claim 3 is a method for manufacturing an automobile wheel using the above rotary forging device, which is a "bottom of the drop center of the rim (1) around the periphery of the disk (2)." In the method for manufacturing a vehicle wheel of a type in which a wall portion is continuously provided, and a side wall portion on the inner rim side of the drop center has a flare shape in which the diameter expands inward, a substantially umbrella-shaped lower surface of the upper mold (301) is used. The upper mold (301) and the upper surface of the lower mold (302) are opposed to each other, and the axis of the upper mold (301) is inclined so that one of the generatrixes of the lower surface of the upper mold (301) is substantially horizontal. The upper surface of the upper mold (30) is made to match the shape of the outer flat surface of the disk (2) and the peripheral surface of the disk (2) to the inner peripheral surface of the outer rim and the side surface of the rim flange that follows.
1) is configured such that a small-diameter body portion (321) is provided on the upper side of a lower body portion (311) continuous with a substantially umbrella-shaped lower surface, and the small-diameter body portion (321) includes a lower mold (302). A cylindrical rotatable auxiliary mold (303) that is coaxial with the external mold is fitted with a margin, and the outer body of this auxiliary mold (303) is aligned with the inner peripheral surface of the side wall of the drop center on the inner rim side. In addition to providing a flare-shaped rim molding surface, match the outer peripheral surface of the lower part of the body (311) with the inner peripheral surface of the bottom wall of the drop center, and attach the rim (1) to the outer body of the pressure roller (4). Shaped part (41) having a shape that matches from the drop center bottom wall part to the outer rim end part on the outer peripheral surface of the
Is equipped with. A step of interposing a work (10) between the upper surface of the lower die (302) and the lower surface of the upper die (301) ,. The lower die (302) and the upper die (301) are rotated synchronously to face each other to bring the workpiece (10) down, and the material protruding from the die boundary portion is pressed by the pressure roller (4). The upper and lower parts are separated by the pressure roller (4) and the lower mold (30
2) is used to form the outer rim, and the upper material is extruded upward from the boundary between the pressure roller (4) and the lower part of the body (311), and this material is moved along the rim forming surface of the auxiliary mold (303). And a step of growing the flare-like inner rim corresponding portion (121) to form a flare-like inner rim, and And a step of finishing a predetermined range from the open end portion of the inner rim corresponding portion (121) into a bead sheet and a rim flange of the inner rim by roll forming ”.

According to this method, since the parts other than the bead seat and the rim flange of the inner rim of the automobile wheel are formed by rotary forging, the productivity of the automobile wheel is improved. [Invention of Claim 4] The invention of Claim 4 is such that, in the invention of Claim 3, the concavo-convex shape formed on the outer flat surface portion of the disk (2) can be accurately formed. Yes, the technical means for that is, "on the outer peripheral side of the rim flange forming part on the upper surface of the lower mold (302), an annular wall (37) having a height corresponding to the wall thickness of this rim flange is provided, Make the rim flange molding part a concave part and set the pressure roller (4)
The lower end surface is arranged in contact with or close to the upper end of the annular wall (37) ”.

In this case, the material protruding from the mold boundary portion and directed downward is the lower end surface of the pressure roller (4) and the annular wall (3).
7) The outer rim is finished in conformity with the cross-sectional shape surrounded by and. Then, after that, the latter half of the disk (2) and the inner rim are molded with the outer periphery of the outer rim being restrained. Therefore, since the uneven portion formed on the outer flat surface portion of the disk (2) is molded in the outer peripheral constrained state, the uneven shape is accurately molded and an incompletely molded portion does not occur. [Invention of Claim 5] The invention of Claim 5 is the invention of Claim 3 or Claim 4, which is intended to further improve the productivity of the automobile wheel. The technical means of "is an annular bending cross-section that is continuous with the upper end of the flared rim forming surface of the auxiliary mold (303) and matches the inner peripheral surface of the bead seat of the inner rim and the rim flange.
(35) was established ”.

In this case, the semi-finished product having the inner rim corresponding part (121) formed thereon is still attached to the rotary forging device, and the predetermined range from the upper end of the inner rim corresponding part (121) is
Since the bead seat and the rim flange of the inner rim are finished by roll forming such as spinning, productivity of the wheel is further improved. [Invention of Claim 6] In the invention of Claim 6, the productivity of the wheel is further improved in the invention of Claim 5, and the technical means therefor is " On the upper side of the first forming part (41) of the pressure roller (4), a second forming part (42) having a body shape that matches the outer peripheral surfaces of the bead seat and the rim flange is provided, and the second forming part (42) is formed by rotary forging. After forming the rim-corresponding part (121), the pressure roller (4) is moved upward, and the predetermined range from the upper end of the inner rim-corresponding part (121) is adjusted to the second forming part of the pressure roller (4). (42) and auxiliary (30
The bead seat and the rim flange are finished by roll-forming with the bent cross-section (35) of 3).

In this structure, after the inner rim corresponding portion (121) is formed by rotary forging, the pressure roller (4) is moved upward to move a predetermined range from the upper end of the inner rim corresponding portion (121). The second molding part (42) of the pressure roller (4) and the auxiliary mold (30
Roll forming with the bent cross section (35) of 3) completes the bead seat and rim flange of the inner rim. According to this method, the step of forming the inner rim equivalent part (121) and the step of roll forming the same can be performed continuously without switching the pressure roller (4), further improving productivity. .

[0017]

Embodiments of the present invention will be described below with reference to the drawings. [Embodiment 1] In Embodiment 1, as shown in FIG. 7, the rim (1) continuously provided on the outer periphery of the disk (2) is provided with a flange (11a) at the front end and protrudes to one side. Example of a rotary forging device for producing a disc with a rim of a straight cylindrical first rim (11) and a second rim (12) of the same shape protruding to the opposite side thereof Is.

[Regarding the structure of each part of the apparatus] Lower mold (302)
As shown in FIG. 4, is formed in a substantially cylindrical shape, and its rotation axis is upright with respect to the horizontal plane. And the upper surface (31) of this is a horizontal surface, and the body part following this upper surface (31) is aligned with the inner peripheral surface of the first rim (11) and the end surface of the flange (11a) following this. A first rim molding surface (32) having a shape to be formed is provided. The lower mold 302 is connected to a rotary shaft 52 of a driving device (not shown) arranged below the lower mold 302, and is rotationally driven at a fixed position.

The lower surface (33) of the upper die (301) is set as an umbrella-shaped surface having a large apex angle, and the body has a truncated cone shape whose upper end is smaller than the lower end as a whole. , A small diameter body (32) above the lower body (311) continuous with the lower surface (33).
1) is connected in series. And this upper mold
The axis of (301) is set to be inclined by about 2 to 5 degrees with respect to the axis of the lower die (302). In this inclined state,
The bottom surface (3
The shape of 3) is set. Further, on the side of the boundary between the upper mold (301) and the lower mold (302), the upper mold (30
A pressure roller (4) described later is arranged on the inclined side of (1). In this upper mold (301), a support shaft protruding from the upper end surface of the upper mold (301) is rotatably supported by a support body (5), and the support body (5) is a hydraulic jack ( It is connected to the lower end of an output shaft (51) hanging from a lower mold (not shown), and the upper die (301) can be moved back and forth in the axial direction of the lower die (302).

The small-diameter body portion (321) of the upper die (301)
A cylindrical auxiliary mold (303), whose upper end is held in a paired state by a support annular body (6) described later, is externally fitted with a margin. The rotation axis of this auxiliary mold (303) matches that of the lower mold (302), and the outer peripheral surface of this auxiliary mold (303) has the same diameter as the inner diameter of the second rim (12) from the upper end to the lower end. A second rim molding surface (34) is provided. The busbar on the pressure roller (4) side of the second rim molding surface (34) is the same as the busbar on the pressure roller (4) side of the outer peripheral surface of the lower body (311) of the upper mold (301). The structure is continuous on the line. Furthermore, in order to realize the above-mentioned pair of rotations, an annular convex portion (36) is provided on the inner peripheral surface of the upper end portion of this auxiliary mold (303), and the other supporting annular body (6) is formed from the central lower surface thereof. It is configured such that a flange (62) is provided on the outer peripheral side of the lower end portion of the protruding cylindrical portion (63), and the annular convex portion (36) is between the cylindrical portion (63) and the flange (62). It is in the form of being inserted into. Further, a bearing for receiving an axial load is interposed between the upper surface of the auxiliary mold (303) and the supporting annular body (6) and between the lower surface of the annular convex portion (36) and the flange (62). Mounted, and the annular protrusion (3
A bearing for receiving a load in the circumferential direction is interposed between the inner peripheral surface of 6) and the tubular portion (63). The support annular body (6) is connected with output shafts (61) (61) hanging from a plurality of hydraulic jacks (not shown) similar to the above, whereby the auxiliary mold (303) is The lower die (302) can be moved up and down in the axial direction.

Further, the pressure roller (4) is rotatably supported by a vertical shaft and is supported so as to be movable in the radial direction of the lower die (302). And, the outer peripheral body portion of this is formed in a substantially columnar shape so as to match the outer peripheral surface in the range from the end portion of the flange (11a) of the first rim (11) to a part of the second rim (12). There is. [Regarding actual molding] When manufacturing the disc with rims shown in FIG. 7 using the above apparatus, first, as shown in FIG. 4, the lower surface of the upper mold (301) and the upper surface of the lower mold (302) are separated. The work (10) is interposed between the two. At this time, the pressure roller (4) is moved to the mold side so that the body portion of the pressure roller (4) has the final shape of the first rim (11) and the straight tube portion (12).
Fix it in a position that matches the outer peripheral surface of a). The work (10) used in this embodiment has a thick disk shape, and its volume is set to be slightly larger than the volume of the rimmed disc in the final molded state.

In this state, the upper mold (301) and the auxiliary mold (303) are synchronously lowered while rotating the lower mold (302).
Then, the upper die (301) rotates synchronously in the same direction as the lower die (302) through the work (10), and the rotary forging action of the lower die (302) and the upper die (301) causes the work ( 10) will be rolled down and flattened. Then, the outer peripheral part gradually protrudes from the boundary part of these molds to the outer peripheral side, and after the protruding material reaches the surface of the pressure roller (4), it is vertically moved by the pressure roller (4). The lower material is separated into the pressure roller (4) and the first of the lower mold (302).
The first rim (11) is finished by extending between the rim forming surface (32) and finally conforming to the forming cross section between them. Further, the upper material is pushed upward from the boundary between the lower part of the body (311) and the pressure roller (4) (state of FIG. 5).
At this time, a gap is not a little formed between the lower end of the auxiliary mold (303) and the lower part of the body (311), but the second gap of the auxiliary mold (303) is not formed.
Since the busbar on the pressure roller (4) side of the rim molding surface (34) is continuous with the busbar on the pressure roller (4) side of the outer peripheral surface of the lower body portion (311) on the same line, The material smoothly transfers to the second rim molding surface (34) over the gap. At this point, the auxiliary type (30
3) This auxiliary type is provided by the frictional resistance between the inner peripheral surface of the material and
(303) starts rotating in the same direction as the material. Then, the material grows upward along the second rim molding surface (34) to form the second rim.
The rim (12) is finished (state of FIG. 6). [Embodiment 2] As shown in FIG. 10, this Embodiment 2 is a rotation for manufacturing a disc with a rim in which the second rim (12) is flared so that its diameter increases toward the open end. This is an embodiment of the forging device, and basically has the same configuration as the rotary forging device of the above-mentioned first embodiment. Incidentally, the second
The end portion of the rim (12) on the disk (2) side is a straight tube portion (12a) having the same diameter as the first rim (11).

In this device, as shown in FIG.
The second rim molding surface (34) of the (303) is flared so that the diameter thereof increases upward, and the flare shape is formed so as to coincide with the inner peripheral surface of the second rim (12). Further, the generatrix of the outer peripheral surface of the lower part of the body (311) on the pressure roller (4) side is aligned with the inner peripheral surface of the straight cylindrical portion (12a). And the second rim molding surface
The lower end of the bus bar on the pressure roller (4) side of (34) and the lower part of the body (3
The outer peripheral surface of 11) is continuous with the extension line of the generating line on the pressure roller (4) side. In addition, pressure roller (4)
Has its outer peripheral body portion matched with the outer peripheral surface in the range from the end portion of the flange (11a) of the first rim (11) to the straight cylindrical portion (12a) of the second rim (12).

When the work (10) is pressed down by using this apparatus in the same manner as in the first embodiment, the material protruding from the boundary of the mold is vertically separated by the pressure roller (4), as shown in FIG. As shown, the lower material is pressure roller (4) and lower mold (302).
The first upper rim molding surface (32) and the upper material from the boundary between the lower body (311) and the pressure roller (4).
It is pushed upwards. Then, the upper material passes over the gap formed between the lower end of the auxiliary mold (303) and the lower body portion (311) and transfers to the second rim molding surface (34), and then the upper material The flare-shaped second rim 12 grows in a diameter-enlarged manner (FIG. 9). [Example 3] Example 3 is a rotary forging apparatus for manufacturing the vehicle wheel shown in FIG.
As shown in FIG. 14, the wheel for an automobile has a disk (2) having an uneven surface on the outer flat surface thereof, and a bottom wall portion of a drop center (110) provided at a position eccentric to the outside of the rim (1). Has a shape continuous with the outer end of the.

In the case of this device, as shown in FIGS. 11 to 13, the upper surface (31) of the lower mold (302) has an outer flat portion of the disc (2) and an outer rim (from the peripheral portion of the disc (2)). While matching the shape of the inner peripheral surface of 114) and the side surface of the rim flange (14) following this, the molding part of this rim flange (14) is a recessed part with an annular wall (37) formed on the outer periphery. ing. or,
An annular bent cross section (35) is continuously provided at the upper end of the second rim molding surface (34) of the auxiliary mold (303). And upper mold (301)
The shape from the lower part of the body (311) to the bent cross section (35) of the auxiliary mold (303) should match the shape of the inner peripheral surface of the inner rim (113) of the rim (1) and the rim flange (13). ing.

Further, the pressure roller (4) is
The outer peripheral surface of the outer rim (114) and the inner surface of the rim flange (14) are matched with the first molding portion (41), and the upper part of the trunk is formed on the inner surface of the rim flange (13) and the inner surface following it. Rim (1
The cylindrical second molding portion (42) is formed so as to coincide with the outer peripheral surface of the bead sheet (13). The second molding portion (42) also has a shape that matches the outer peripheral surface of the bottom wall portion of the drop center (110).

When molding the rim (1) using this apparatus, as shown in FIG. 11, the pressure roller (4) is attached to the lower mold.
A small gap is made between the upper end of the annular wall (37) of the (302) and the upper end of the annular wall (37).
0) is maintained at a position corresponding to the outer peripheral surface in the range from the bottom wall portion to the outer rim (114). In this state, when the work (10) is pressed down in the same manner as in Example 1, the material protrudes annularly from the mold boundary portion and reaches the surface of the pressure roller (4), and then the material is separated into upper and lower parts. The material directed downward is the outer rim including the rim flange (14) in conformity with the sectional shape surrounded by the first molding portion (41) of the pressure roller (4) and the annular wall (37).
It is finished to (114) (state of FIG. 12). At this time, the front end of the material is closed by the annular wall (37) and the lower end surface of the pressure roller (4), so that the material is prevented from flowing downward at this point and the material flows only upward. It will be. On the other hand, the material that goes up is the lower part of the body (311) and the pressure roller.
The second rim forming surface (34) is pushed upward in the axial direction from the boundary with the upper part of (4) and goes beyond the gap formed between the lower end of the auxiliary mold (303) and the lower part of the body (311). After transferring to
Along with this, it grows in a diameter-enlarged manner and is molded into an inner rim corresponding portion (121) shown by a broken line in FIG.

Thereafter, while the pushing down of the upper die (301) is stopped, the pressure roller (4) is moved upward (indicated by the chain double-dashed line in the figure), and the second molding part (42) ) And auxiliary (303)
When a predetermined range from the upper end of the inner rim equivalent part (121) is roll-formed by the bent cross-section part (35) of this, this range becomes a rim flange (13) and a bead seat following it, and the inner rim (113) Is finished. This completes the molding of the entire rim (1).

In this case, since the latter half of the disk (2) is molded while the outer periphery of the outer rim is restrained, the uneven portion of the outer flat surface of the disk (2) is accurately molded.
Further, the step of forming the inner rim corresponding portion (121) and the step of forming the upper end portion of the inner rim corresponding portion (121) can be performed continuously without switching the pressure roller (4), so that the productivity is improved.

[Modification] In the first and second embodiments, the cross section of the flare-shaped second rim molding surface (34) of the auxiliary mold (303) has an arcuate shape which is convex toward the inner peripheral side. It goes without saying that it is good. ． The roll processing in the third embodiment may be performed by using a spinning roller different from the pressure roller (4).

.. In any of the above embodiments, the upper mold (301) is not directly driven to rotate, but it is directly driven by a driving motor or the like to rotate the upper mold (301) and lower mold (302). The configuration may be synchronized with the rotation of the. or,
The auxiliary type (303) may also be rotated synchronously. ． In any of the above embodiments, the auxiliary mold (303) is replaced with the upper mold (301).
Although it is a method of descending in synchronization with the
As long as it is possible to transfer smoothly from the outer peripheral surface of the lower part of the body (311) of 01) to the rim forming surface of the auxiliary mold (303),
You may hold | maintain (303) in a fixed position and let only an upper mold | type (301) fall.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of the initial stage of a process when a conventional rotary forging device is used.

FIG. 2 is an explanatory diagram of the middle stage of the process.

FIG. 3 is an explanatory diagram at the end of this process.

FIG. 4 is an explanatory diagram of the initial stage of the process when the rotary forging device of Example 1 is used.

FIG. 5 is an explanatory diagram of the middle stage of this process.

FIG. 6 is an explanatory diagram at the end of this process.

FIG. 7 is a sectional view of a rimmed disc manufactured thereby.

FIG. 8 is an explanatory view of the middle stage of the process when the rotary forging device according to the second embodiment is used.

FIG. 9 is an explanatory diagram at the end of this process.

FIG. 10 is a cross-sectional view of a rimmed disc having a flared rim produced thereby.

FIG. 11 is a sectional view of the initial stage of the process when the rotary forging device of Example 3 is used.

FIG. 12 is an explanatory diagram of the middle stage of this process.

FIG. 13 is an explanatory diagram at the end of this process.

FIG. 14 is a sectional view of an automobile wheel manufactured thereby.

[Explanation of symbols]

 (301) ・ ・ ・ Upper mold (302) ・ ・ ・ Lower mold (303) ・ ・ ・ Auxiliary mold (10) ・ ・ ・ Workpiece (4) ・ ・ ・ Pressure roller (2) ・ ・ ・ Disc (1)・ ・ ・ Rim (311) ・ ・ ・ Lower body (321) ・ ・ ・ Small diameter body (121) ・ ・ ・ Inner rim equivalent part (37) ・ ・ ・ Annular wall (35) ・ ・ ・ Bending section (41 ) ・ ・ ・ First molding part (42) ・ ・ ・ Second molding part

Claims (6)

[Claims] 1. A substantially umbrella-shaped lower surface of an upper mold (301) and a lower mold (30
While facing the upper surface of 2), one of the upper mold (301) is arranged so that one of the generatrix of the lower surface of the upper mold is substantially horizontal.
Inclining the axis of (01), the upper mold (301) is
2) A cylindrical rotatable auxiliary mold (303) coaxial with 2) is externally fitted, and the work (10) is interposed between the lower surface of the upper mold (301) and the upper surface of the lower mold (302). The upper mold (301) and the lower mold (302)
While rotating synchronously with and, these dies are made to face each other and the work (10) is pressed down, and the material protruding from this reduction area is arranged on the side of the mold boundary and on the inclined side of the upper mold (301). In the rotary forging device that separates the rim (1) from the top and bottom by the pressure roller (4), and forms the rim (1) that overhangs the top and bottom of the disc (2), the upper die (301) has a continuous bottom surface. A small diameter body (321) is provided on the upper side of the lower body (311) to be fitted, and the auxiliary die (303) is fitted onto the small diameter body (321) with a margin, and the rim forming surface of the auxiliary die (303) is A rotary forging machine in which the bus bar on the pressure roller (4) side is continuous with the extension line of the bus bar on the pressure roller (4) side on the outer peripheral surface of the lower body (311). 2. The rotary forging device according to claim 1, wherein the rim forming surface of the auxiliary die (303) has a flare shape in which the diameter is enlarged upward. 3. A bottom wall portion of the drop center of the rim (1) is continuously provided around the periphery of the disc (2), and a side wall portion of the drop center on the inner rim side has a flare shape in which the diameter increases toward the inside. In the method for manufacturing a vehicle wheel of a type, the substantially umbrella-shaped lower surface of the upper mold (301) and the upper surface of the lower mold (302) are made to face each other, and one of the bus bars of the lower surface of the upper mold (301) is substantially Inclining the axis of this upper mold (301) so that it is horizontal,
The upper surface of the lower mold (302) conforms to the shapes of the outer flat surface of the disk (2) and the peripheral surface of the disk (2) to the inner peripheral surface of the outer rim and the side surface of the rim flange that follows the upper surface of the lower mold (302). (3
01) has a structure in which a small diameter body portion (321) is provided on the upper side of a lower body portion (311) continuous with a substantially umbrella-shaped lower surface, and the lower die (302) is provided in the small diameter body portion (321). A cylindrical rotatable auxiliary mold (303) that is coaxial with the external mold is fitted with a margin, and the outer body of this auxiliary mold (303) is aligned with the inner peripheral surface of the side wall of the drop center on the inner rim side. In addition to providing a flare-shaped rim molding surface, match the outer peripheral surface of the lower part of the body (311) with the inner peripheral surface of the bottom wall of the drop center, and attach the rim (1) to the outer body of the pressure roller (4). Shaped part (41) having a shape that matches from the drop center bottom wall part to the outer rim end part on the outer peripheral surface of the
Is equipped with. A step of interposing a work (10) between the upper surface of the lower die (302) and the lower surface of the upper die (301) ,. The lower die (302) and the upper die (301) are rotated synchronously to face each other to bring the workpiece (10) down, and the material protruding from the die boundary portion is pressed by the pressure roller (4). The upper and lower parts are separated by the pressure roller (4) and the lower mold (30
2) is used to form the outer rim, and the upper material is extruded upward from the boundary between the pressure roller (4) and the lower part of the body (311), and this material is moved along the rim forming surface of the auxiliary mold (303). And a step of growing the flare-like inner rim corresponding portion (121) to form a flare-shaped inner rim corresponding portion (121), and. A method for manufacturing an automobile wheel, comprising a step of rolling a predetermined range from an open end portion of the inner rim equivalent portion (121) into a bead sheet and a rim flange of the inner rim. 4. An annular wall (37) having a height corresponding to the wall thickness of the rim flange is provided on the outer peripheral side of the rim flange forming part on the upper surface of the lower die (302), and the rim flange forming part is recessed. The method for manufacturing an automobile wheel according to claim 3, wherein the pressure roller (4) is arranged in a state where its lower end surface is in contact with or close to the upper end of the annular wall (37). 5. An annular bending cross-section (35) which is continuous with the upper end of the flared rim forming surface of the auxiliary mold (303) and which matches the bead seat of the inner rim and the inner peripheral surface of the rim flange. Item 5. A method for manufacturing an automobile wheel according to Item 3 or 4. 6. The pressure roller (4) is provided with a second molding portion (42) having a body shape on the upper side of the first molding portion (41), the shape of the body of the pressure roller (4) conforming to the outer peripheral surfaces of the bead seat and the rim flange. After the inner rim corresponding part (121) is formed by rotary forging, the pressure roller (4) is moved upward so that the predetermined range from the upper end of the inner rim corresponding part (121) is adjusted to the pressure roller (4). 6. The bead seat and the rim flange are finished by roll-forming by the second forming part (42) of No. 2 and the bent cross-section part (35) of the auxiliary mold (303).
A method for manufacturing an automobile wheel according to.