JP4100565B2 - Forging case molding method - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method for forming a forged case having a flange on the outer periphery near the opening and a spline on the inner periphery.
[0002]
[Prior art]
Conventionally, a case having a flange formed circumferentially on the outer periphery and a spline extending in the axial direction on the inner periphery has been generally formed by casting. However, the case formed by casting has low strength, and it is necessary to increase the thickness of the case in order to obtain a predetermined strength, which increases the weight. Therefore, in recent years, cases are often formed by forging that provides high strength even with the same wall thickness as casting.
[0003]
Here, the process of forming a case by forging will be described with reference to FIG. 5. First, a cylindrical cutting material W100 ((A) in FIG. 5) obtained by cutting a wire to a required length is pressed in the axial direction to form a disk. Cup-shaped case W103 (FIG. 5 (C)) having flange 115 on the outer periphery near opening 117 and spline 116 on the inner periphery is formed by molding a sheet-shaped material W101 (FIG. 5A). Was.
[0004]
Here, the process for forming the case W103 from the material W101 in the forging process will be described with reference to FIGS.
[0005]
First, the forging device 121 will be described with reference to FIG. 6. Reference numeral 151 denotes a fixed die, a die 155 that defines a die-cutting space 156 into which the material W 101 is charged, and the die-cutting space 156 in the vicinity of the axis of the die 155. A molding surface 158 having the same shape as the outer surface of the desired case W103 is formed by the inner wall surface 157 of the die 155 and the end surface of the knockout pin 162, which are provided with knockout pins 162 that can be freely arranged and form the engraving space 156. Reference numeral 131 denotes a movable die, which includes a punch 132 provided with a spline tooth die 132a for forming the spline 116 of the case W103 on the outer periphery, and a pin 135 disposed in the vicinity of the axial center of the punch 132. The pressing surface 133 having the same shape as the inner bottom surface of the case W103 is formed by the end surface.
[0006]
When the case W103 is formed from the material W101 by the forging device 121, first, the material W101 is put into the mold engraving space 156 of the fixed die 151, and then the movable die 131 is lowered, as shown in the left half of FIG. Pressing is performed between the molding surface 158 of the die 155 and the pressing surface 133 of the punch 132, the forged meat of the material W101 is pushed forward and backward as shown in the right half of FIG. 7, and the forging case W103 is shown in FIG. Molded.
[0007]
[Problems to be solved by the invention]
As described above, the desired case W103 can be formed by pressing the material W101 in the axial direction between the fixed mold 151 and the movable mold 131. Here, when a case W103 having a flange 115 on the outer periphery and a spline 116 on the inner periphery is formed by extrusion forging from a disk-shaped material W101, the forged meat is between the inner wall surface 157 of the die 155 and the spline tooth mold 132a of the punch 132. As shown in the right half of FIG. 7, the forged meat filled in the axial direction flows in the radial direction while forming the spline 116 on the inner periphery, and then flows radially outward, as shown in FIG. Thus, the flange 115 is finally formed. Therefore, when the forged meat flows radially outward when the flange 115 is formed, the forged meat on the spline 116 side formed on the inner periphery may be insufficient, and the accuracy of the spline may be reduced.
[0008]
Therefore, as shown in FIG. 9, after forming a cup-shaped preform 202 (FIG. 9C) having a cylindrical preliminary circular wall portion 204 from a material W201 (FIG. 9A), a preliminary circle is formed. The wall portion 204 is pressed in the axial direction, and the spline 216 and the flange 215 are formed by causing the forged meat to flow inward and outward in the radial direction. According to this forming method, the forged meat flows inward and outward in the radial direction at the same time. Therefore, there is an advantage that the flow of the forged meat in the radially outward direction is suppressed. However, even in this case, the flow amount of the forged meat inward and outward in the radial direction cannot be made uniform, the forged meat on the spline 216 side having a small flow amount is insufficient, and the accuracy of the spline 216 is lowered. is there.
[0009]
Accordingly, an object of the present invention is to solve the above-described problems and to provide a method for forming a forged case in which the flange and the spline have high accuracy.
[0010]
[Means for Solving the Problems]
The present invention is as follows.
[0011]
In a method for forming a forged case having a flange formed on the outer periphery and a spline extending in the axial direction on the inner periphery, the preformed material is subjected to extrusion molding, and the one end of the preliminary bottom portion is substantially the same as the desired flange. A first step of forming a preform having a pre-shaped flange and a pre-projection extending in one axial direction from the inside of the pre-flange, and the other outer end face of the pre-bottom of the pre-formed product is splined on the outer periphery. Place the preform on the mandrel so that it abuts the mandrel with the mold, and while maintaining the shape of the spare flange, press the spare flange and the spare projection in the other axial direction to imitate the spline teeth of the mandrel. And a second step of forming a circular wall surface having a flange on the outer periphery on the other opening side and a spline on the inner periphery by flowing the forged meat in the axial direction.
[0012]
【Example】
Embodiments of the present invention will be described below with reference to FIGS.
[0013]
FIG. 1 shows a process of forming a forging case W3 (FIG. 1D) having a flange 15 formed circumferentially on the outer periphery and a spline 16 extending in the axial direction on the inner periphery. First, a cylindrical cutting material W0 ((A) in FIG. 1) obtained by cutting the wire into a required length is pressed in the axial direction to form a disk-shaped material W1 ((A) in FIG. 1), and then extrusion molding. Thus, a preform W2 (see FIG. 1) having a spare flange 5 having substantially the same shape as the desired flange 15 on the outer circumference of the one-side spare bottom 6 and having a spare protrusion 4 extending in the one axial direction from the inside of the spare flange 5. (C)) is molded. Finally, the preformed product W2 is extruded to form the case W3.
[0014]
Here, a process of forming the case W3 from the preform W2 will be described with reference to FIGS.
[0015]
First, the forging device 21 will be described with reference to FIG. A mandrel 52 is provided. The mandrel 52 protrudes toward the carved space 56, and a spline tooth die 53 is formed on the outer periphery of the protruding portion. On the inner peripheral side of the mandrel 52, a knockout pin 62 that is urged toward the anti-engraved space side by a spring 59 and is movable back and forth with respect to the engraved space 56 is disposed, and the die 55, the mandrel 52, and the knockout pin 62 are desired. A molding surface 58 having the same shape as the outer surface of one end of the case W3 is formed. The die 55 is supported by a cylindrical support die 60 and a base 61 arranged concentrically. On the inner peripheral side of the base 61, an auxiliary pin 63 that abuts on the knockout pin 62 and is arranged concentrically. Inserted.
[0016]
Subsequently, 31 is a movable die, and includes a punch 32 that presses the preform W2 and a pin 35 disposed in the vicinity of the axial center of the punch 32. The pin 35 is attached to the anti-engraved space side by a spring 36. Be forced. A pressing surface 33 having the same shape as the outer surface of the other end of the desired case W3 is formed on the end surface of the punch 32 and the pin 35 on the mold engraving space 56, and an outer peripheral pressing surface 33a and an inner peripheral side are formed on the outer peripheral side of the pressing surface 33. Has an inner peripheral pressing surface 33b, and a punch inner peripheral surface 33c is provided on the inner periphery of the punch 32 connecting the pressing surfaces 33a and 33b. The punch 32 and the pin 35 are integrally fixed by a punch holder 37 to a slide 38 that is movable in the axial direction, and are arranged at a position facing the die-sculpting space 56 of the fixed die 51.
[0017]
When the case W3 is formed from the preform W2 by the forging device 21, the preform W2 is placed on the mandrel 52 so that the outer end surface 6a of the preform bottom 6 of the preform W2 is in contact with the mandrel 52 by a transport device (not shown). Placed on. Subsequently, the movable die 31 is lowered, and as shown in the left half of FIG. 3, the outer peripheral pressing surface 33a of the punch 32 of the moving die 31 is used as the preliminary flange 5 of the preform W and the inner peripheral pressing surface 33b is preformed. Simultaneously with the contact with the preliminary projection 4 of the product W2, the movable die 31 is further lowered as shown in the right half of FIG. 3, and the preliminary flange 5 and the preliminary projection 4 are pressed downward. At this time, since the preliminary flange 5 moves downward along the gap between the spline tooth mold 53 of the mandrel 52 and the inner wall surface 57 of the die 55, it is pressed downward while maintaining the shape of the preliminary flange 5. However, since the preliminary projection 4 cannot move with the preliminary bottom 6 in contact with the mandrel 52, the preliminary projection 4 is splined between the spline teeth 53 of the mandrel 52 and the punch inner peripheral surface 33 c of the punch 32. The forged meat flows in the axial direction following the tooth mold 53. As shown in FIG. 4, the preliminary flange 5 is finally pressed between the molding surface 58 of the die 55 and the outer peripheral pressing surface 33a of the punch 32, and the preliminary projection 4 has the spline 16 on the inner periphery. It is formed into a circular wall surface 14. Thereafter, the movable die 31 is retreated upward, and the knockout pin 62 is raised by the auxiliary pin 63 of the fixed die 51, and the case W3 formed from the die-sculpting space 56 of the fixed die 51 is taken out, and this process is completed.
[0018]
Therefore, the preliminary flange 5 having substantially the same shape as the flange 15 that is likely to be short of forged meat is formed in the first step, and the forged meat of the preliminary projection 4 flows in the axial direction while maintaining the preliminary flange 5, Since the circular wall surface 14 having the flange 15 and the spline 16 on the inner periphery is formed, the flow of the forged meat to the radially inner side and the outer side where the flange 15 and the spline 16 are formed can be minimized.
[0019]
In the above embodiment, a cup-shaped case that closes one end is used as the forged case W3. However, a cylindrical case that is open at both ends may be used.
[0020]
【The invention's effect】
As described above, according to the present invention, in a method for forming a forged case having a flange formed on the outer periphery in a circumferential shape and a spline extending in the axial direction on the inner periphery, the preformed material is subjected to extrusion molding, A first step of forming a preform having a preliminary flange having substantially the same shape as the desired flange on the outer periphery of the bottom, and having a preliminary projection extending in one axial direction from the inside of the preliminary flange, and a preliminary bottom of the preliminary product Place the preformed product on the mandrel so that the other outer end face of the mandrel has a spline tooth shape on the outer periphery, and maintain the shape of the spare flange, and move the spare flange and spare protrusion in the other axial direction. Press to cause the forged meat to flow in the axial direction following the spline teeth of the mandrel, and to form a circular wall surface having a flange on the other opening side outer periphery and a spline on the inner periphery. Because and a step, the flow of forging meat radially inner and outer flanges and splines are formed can minimized, thereby forming a flange and the spline with high accuracy.
[Brief description of the drawings]
FIG. 1 is a cross-sectional plan view illustrating a method for forming a forged case according to an embodiment of the present invention.
FIG. 2 is a partial cross-sectional plan view showing a first stage of a forging case forming method according to an embodiment of the present invention.
FIG. 3 is a partial cross-sectional plan view illustrating a method for forming a forged case according to an embodiment of the present invention, in which the left half represents a second stage and the right half represents a third stage.
FIG. 4 is a partial cross-sectional plan view showing the final stage of the forging case forming method according to the embodiment of the present invention.
FIG. 5 is a cross-sectional plan view illustrating a conventional forging case forming method.
FIG. 6 is a partial sectional plan view showing a first stage of a conventional forging case forming method.
FIG. 7 is a partial cross-sectional plan view showing a conventional forging case forming method, in which the left half represents the second stage and the right half represents the third stage.
FIG. 8 is a partial cross-sectional plan view showing the final stage of a conventional forging case forming method.
FIG. 9 is a cross-sectional plan view showing another conventional forging case forming method.
[Explanation of symbols]
4 Preliminary projection 5 Preliminary flange 6 Preliminary bottom 6a Outer end surface 14 Circular wall surface 15 Flange 16 Spline 17 Opening 52 Mandrel 53 Spline tooth type W1 Material W2 Preliminary product

Claims (1)

In a method for forming a forged case having a flange (15) formed circumferentially on the outer periphery and a spline (16) extending in the axial direction on the inner periphery, the preformed material (W1) is subjected to extrusion forming, and one end preliminary bottom portion (6) Preliminary forming having a preliminary flange (5) having substantially the same shape as the desired flange (15) on the outer periphery, and having a preliminary projection (4) extending in one axial direction from the inside of the preliminary flange (5). The first step of forming the product (W2) and the other outer end surface (6a) of the preliminary bottom (6) of the preformed product (W2) contact the mandrel (52) having a spline tooth mold (53) on the outer periphery. The preform (W2) is placed on the mandrel (52) so as to come into contact, and the spare flange (5) and the spare projection (4) are pressed in the other axial direction while maintaining the shape of the spare flange (5). Mandrel (52) A forged meat is caused to flow in the axial direction following the spline tooth mold (53), and a circular wall surface (14) having a flange (15) on the outer periphery on the other opening (17) side and a spline (16) on the inner periphery is formed. A forging case forming method comprising two steps.

Images