JP5099877B2 - Forming method of forged products - Google Patents

Description

  The present invention relates to a molding method for molding a forged product having a tooth profile on the outer periphery and a through hole in an axial center portion.

  Conventionally, in a molding method for forming a forged product having a tooth shape on the outer periphery and a through hole in the shaft center portion, a pre-forged product having an outer diameter smaller than the tooth forming shape portion is formed on a forming die having a tooth forming shape portion on the inner periphery. Inserting and pressing the axially opposite ends of the preliminary forging product with a punch expands the preliminary forging product in the radial direction, forms a tooth profile on the outer periphery of the preliminary forging product, and forms a recess on both axial ends Form a forged product. And the bottom part of the recessed part of an intermediate forging product is punched out with the punch, and the forging product which has a through-hole in an axial center part is shape | molded (refer patent document 1).

Further, in a different molding method for forging products having a tooth shape on the outer periphery and a through hole in the shaft center portion, the tooth forming shape portion and the outer diameter of the tooth forming shape portion are substantially the same diameter on the forming die having the tooth forming shape portion on the inner periphery. A forged product having a tooth profile on the outer periphery and a through hole in the axial center is formed by press-fitting a pre-forged product having a through hole into the outer periphery. When the preliminary forged product is press-fitted into the forming die, the upper punch presses the upper surface of the preliminary forged product, and the lower punch moves while supporting the lower surface of the preliminary forged product (see Patent Document 2).
Japanese Patent Laid-Open No. 9-10883 JP-A-60-37237

  However, in the tooth profile forming method disclosed in Patent Document 1, as shown in FIGS. 1 and 5 of Patent Document 1, the upper and lower punches cause the flesh of the pre-forged product to flow and expand in the radial direction. When the pre-forged product comes into contact with the tooth forming part of the forming die, a frictional force is generated between the meat flowing in the radial direction and the tooth forming part. It was.

  Therefore, as shown in Fig. 5 of Patent Document 2, a material having a diameter substantially the same as the diameter of the tip circle of the desired tooth shape is press-fitted in the axial direction into the tooth forming portion of the forming die so that the tooth tip does not become thin. There is a method for forming a tooth profile. However, in the tooth shape molding method in which a material having the same diameter as the tip circle diameter of the desired tooth shape is press-fitted in the axial direction into the tooth forming shape portion of the forming die, the meat flowing in the axial direction and the tooth forming shape portion of the forming die are Since a frictional force is generated between them, as shown in FIG. 2 of Patent Document 2, there is a problem that a thin wall is formed on one end side in the axial direction of the tooth profile.

  The present invention has been made in view of the above circumstances, and in a method for forming a forged product having a tooth shape on the outer periphery and a through hole in the shaft center portion, there is no lack of thickness on the tooth tip and one end side in the axial direction of the tooth shape. An object is to provide a forming method for forming a forged product.

The method for forming a forged product according to the present invention is a method for forming a forged product having a tooth profile on the outer periphery and a through hole in the shaft center portion, and forming a flange from a pre-forged product having a spare flange on the outer periphery on the other end side. In an intermediate forged product forming method for forming an intermediate forged product having an intermediate forged product forming die having a tooth forming shape portion on the inner periphery, a spare flange portion on the other end outer periphery, and a tooth tip diameter of the tooth profile approximately A pre-forged product of the same diameter is press-fitted from one end side in the axial direction of the pre-forged product, and at the same time a tooth profile is formed on the outer periphery of the pre-forged product,
The axial center part on one end side of the pre-forged product is pressed with the first punch, and the first concave part is formed on the axial center part on the one end side, so that the meat of the axial center part on the one end side is one end in the axial direction of the tooth profile. Forming an intermediate forged product having a flange that is flowed to the outer periphery and forming a tooth profile, and forming an intermediate forged product that forms a space between the intermediate forged product flange and the intermediate forged product forming die having a tooth forming profile. Process,
The first feature is to have a piercing forming step of forming a forged product by punching the bottom of the first concave portion of the intermediate forged product to form a through hole.

  The forging product molding method of the present invention has a second feature that the tooth profile is a helical shape.

The method for forming a forged product of the present invention is such that a pre-forged product having a diameter substantially the same as the tooth tip circle diameter of a tooth profile is formed on one end side in the axial direction of the pre-forged product. Press-fit to form a tooth profile on the outer periphery of the pre-forged product, one end side of the pre-forged product abuts the first punch, and further presses the shaft center on one end side of the pre-forged product with the first punch, By forming the first concave portion in the shaft center portion, the meat of the shaft center portion on one end side is caused to flow to the outer periphery on one end side in the axial direction of the tooth shape to form the tooth shape, and the other end side of the preliminary forged product is the second punch. The second recess is formed in the shaft center part by pressing, the other end side end face of the second recess does not contact the movable mold, and the other end side shaft center part is the outer periphery of the pre-forged product. The intermediate forged product forming step for forming the intermediate forged product, and punching the bottom of the first recess of the intermediate forged product to form the through hole By shape, the piercing forming step of forming a forged product, was closed during forging molding process in you forming an intermediate forged product having a flange portion from the preliminary forging having a preliminary flange portion on the other end side outer circumference The third feature is that a space is formed between the intermediate forging product dies and the intermediate forging product forming die having the tooth forming portion at the completion of the above.
Moreover, the shaping | molding method of the forge product of this invention makes it 4th characteristic that a tooth profile is a helical shape.

According to the method for forming a forged product according to the first feature of the present invention, the intermediate forging product forming die having a tooth forming shape portion on the inner periphery, the spare end portion on the other end side outer periphery, and the tooth tip diameter of the tooth shape. Since the pre-forged product having the same diameter as that of the pre-forged product is press-fitted from one end side in the axial direction of the pre-forged product, the pre-forged product is less likely to flow in the radial direction. That is, the frictional force in the radial direction is reduced between the pre-forged product meat and the tooth-forming portion of the intermediate forged product forming die, and the tooth tip does not become thin. On the other hand, an axial frictional force is generated between the meat of the pre-forged product and the tooth forming portion of the intermediate forged product forming die, and it is easy to form a thin wall on one end side of the tooth profile. By pressing the part with the first punch and forming the first recess on the one end side of the axial center part of the pre-forged product, the meat of the axial center part on the one end side is caused to flow to the outer periphery on the one end side in the axial direction of the tooth profile. Therefore, it is possible to prevent a lack of thickness from occurring on one end side of the tooth profile.
Further, when the intermediate forging product forming step is completed, a space is formed between the intermediate forging product forming die having the flange portion and the tooth forming shape portion. That is, since the flow of meat is not suppressed, the load on the intermediate forging product forming die can be reduced.

According to the method for forming a forged product of the second feature of the present invention, the tooth profile is a helical shape, the tooth groove of the tooth forming portion is inclined with respect to the axial direction, and the flow of meat in the axial direction is suppressed. Even if it is a case, the helical tooth profile which does not have a lack of thickness on the one end side of the axial direction of the intermediate forging product can be formed.

According to the method for forming a forged product of another third feature of the present invention, a preliminary forged product having the same diameter as the tip circle diameter of the tooth profile is preliminarily placed on the intermediate forged product forming die having the tooth forming shape portion on the inner periphery. Since press-fitting is performed from one end side in the axial direction of the forged product, the meat of the pre-forged product hardly flows in the radial direction. That is, the frictional force in the radial direction is reduced between the pre-forged product meat and the tooth-forming portion of the intermediate forged product forming die, and the tooth tip does not become thin. On the other hand, an axial frictional force is generated between the meat of the pre-forged product and the tooth forming portion of the intermediate forged product forming die, and it is easy to form a thin wall on one end side of the tooth profile. Part is pressed with the first punch, the first recess is formed on one end side of the axial center portion of the pre-forged product, and the other end side of the pre-forged product is pressed by the second punch, so that the second concave portion is formed on the axial center portion. The other end side end surface of the second recess is not in contact with the movable mold, and the axial center part on the other end side flows to the outer periphery on the other end side of the pre-forged product, so Can be made to flow to the outer periphery on one end side in the axial direction of the tooth profile, so that it is possible to prevent a lack of thickness from occurring on one end side of the tooth profile.
Also, when the middle forging molding steps completed, the space between the intermediate forging molding die having a flange portion and a tooth forming portion of the intermediate forged product is formed. That is, since the flow of meat is not suppressed, the load on the intermediate forging product forming die can be reduced.
According to the forged product forming method of another fourth aspect of the present invention, the tooth profile is a helical shape, the tooth groove of the tooth forming portion is inclined with respect to the axial direction, and the meat flows in the axial direction. Even if this is suppressed, it is possible to form a helical tooth profile without a lack of thickness on one end side in the axial direction of the intermediate forged product.

  Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a sectional plan view showing a manufacturing process of a forged product of the present invention. FIG. 2 is a cross-sectional plan view showing a pre-forged product forming step for forming the pre-forged product of the present invention. FIG. 3 is a cross-sectional plan view showing an intermediate forged product forming step of forming an intermediate forged product having a tooth profile formed on the outer periphery of the present invention. FIG. 4 is a cross-sectional plan view showing a piercing process for forming a forged product having a through hole in the axial center of the present invention. 5A is a cross-sectional plan view showing the first stage in the intermediate forged product forming process, FIG. 5A is a cross-sectional plan view showing the second stage in the intermediate forged product forming process, and FIG. Is a cross-sectional plan view showing the third stage in the intermediate forged product forming process, FIG. 6A is a cross-sectional plan view showing the fourth stage in the intermediate forged product forming process, and FIG. FIG.

  First, a processing shape from the columnar material W0 to the forged product W3 will be described with reference to FIG. The columnar material W0 ((A) in FIG. 1) obtained by cutting the wire into a required length is pressed in the axial direction, so that one end side in the axial direction as shown in (A) in FIG. It becomes the preliminary forging product W1 in which the preliminary hook portion 61 is formed on the cylindrical portion 62 and the other end side. Next, as shown in FIG. 1C, the preliminary forged product W1 has a helical tooth profile 63 on the outer circumference on one end side in the axial direction, and a first recess 71 and an axial line on the axial center portion on one end side in the axial direction. This is an intermediate forged product W2 in which a flange 66 is formed on the outer periphery on the other end side in the direction and a second recess 72 is formed on the axial center portion on the other end side in the axial direction. The first recess 71 has a bottom 75 inside. In the intermediate forged product W2, the tooth profile 63 is sized by ironing, the bottom 75 is punched out, and as shown in FIG. 1D, the desired helical profile tooth profile 63 on the outer periphery, and the through hole in the shaft center portion. 76 becomes the forged product W3 formed.

  Next, the pre-forged product forming apparatus 1 for forming the pre-forged product W1, the intermediate forged product forming device 21 for forming the intermediate forged product W2, and the piercing device 41 for forming the forged product W3 will be described with reference to FIGS. To do.

  A pre-forged product forming apparatus 1 shown in FIG. 2 includes a movable die 2 and a fixed die 11. The movable die 2 has a punch 3 and a punch holder 4 that holds the punch 3. The fixed die 11 is arranged at the axial center portion of a pre-forged product forming die 13 having a die engraving space 12 for forming the pre-forged product W1, and the pre-forged product forming die 13, and is used for forming the pre-forged product W1. A knockout 14 constituting a part of the space 12, a knockout pin 15 that supports the knockout 14 so as to be able to advance and retreat, and a knockout holder 16 that holds the knockout 14 and the knockout pin 15 are provided.

  The intermediate forging product forming apparatus 21 shown in FIG. 3 includes a movable die 22 and a fixed die 31. The movable die 22 includes a second punch 23, a punch guide 24 that holds the second punch 23, a punch guide holder 25 that holds the punch guide 24, and a punch holder 26 that holds the second punch 23. The fixed die 31 is arranged at the axial center portion of the intermediate forging product forming die 33 and the intermediate forging product forming die 33 having the engraving space 32 in which the tooth forming shape portion 38 is formed. The first punch 34 to be pressed, the knockout 35 which is disposed on the outer periphery of the first punch 34 and constitutes a part of the engraving space 32, the knockout pin 36 which supports the knockout 35 so as to freely advance and retract, and the knockout 35 and the knockout pin 36 are provided. It has a knockout holder 37 for holding it.

  The piercing device 42 shown in FIG. 4 includes a moving die 42 and a fixed die 51. The movable die 42 is disposed inside the pierce stripper 44, a piercing stripper 44 that presses the intermediate forged product W3 against the fixed die 51, a piercing stripper holder 45 that holds the piercing stripper 44, a positioning member 47 that regulates the amount of movement of the piercing stripper 44, And a piercing punch 43 for forming the through hole 76 in the intermediate forging product W2 and a punch holder 46 for holding the piercing punch 43. The fixed die 51 is a forged product forming die 53 having a die engraving space 52 in which a sizing tooth die 57 for sizing the tooth profile 63 formed in the intermediate forged product W2 by ironing is formed, and intermediate forging punched by the piercing punch 43. The bottom outlet 54 for discharging the bottom 75 of the first recess of the product W2 has a knockout 55 formed therein, and a knockout pin 56 that supports the knockout 55 so as to be movable back and forth.

  Next, a method of forming the forged product W3 from the columnar material W0 will be sequentially described.

  First, a columnar material W0 obtained by cutting a wire into a required length is placed in a mold engraving space 12 formed in the fixed mold 11 of the pre-forging apparatus 1 by a conveying device (not shown). Subsequently, as shown in FIG. 2, the punch 3 is moved downward to press the columnar material W <b> 0, and a cylindrical portion 62 having substantially the same diameter as the tooth shape 63 formed on one end side in the axial direction, and the axial direction A pre-forged product W <b> 1 in which a preliminary brim portion 61 is molded on the other end side is formed. When the formation of the preliminary forged product W1 is completed, the punch 3 is retracted upward. Thereafter, the knockout pin 15 is moved upward by the knockout pin 15, and the preliminary forged product W1 is taken out from the preliminary forged product forming die 13.

  Subsequently, the pre-forged product W1 taken out is placed in the engraving space 32 formed in the fixed die of the intermediate forged product forming device 21 by a transport device (not shown). At this time, as shown in FIG. 5A, since the outer diameter of the cylindrical portion 62 of the preliminary forged product W1 is larger than the inner diameter of the tooth forming portion 38 of the intermediate forged product forming die 33, one end of the preliminary forged product W1. The cylindrical portion 62 on the side is placed on the tooth forming portion 38 of the intermediate forging product forming die 33.

  Next, as shown in FIG. 5 (a), when the axial center portion on the other end side of the preliminary forged product W1 is pressed by the second punch 23, the cylindrical portion 62 of the preliminary forged product W1 is formed into an intermediate forged product. A helical tooth profile 63 is formed on the outer periphery by being press-fitted into a tooth forming profile 38 formed on the die 33. Here, when the one end side of the preliminary forging product W1 comes into contact with the first punch 34, a frictional force is generated between the meat flowing in the axial direction and the tooth forming shape portion 38 of the intermediate forging product forming die 33, thereby flowing in the axial direction. However, the thinned portion 64 is formed on the outer periphery on the one end side of the formed tooth profile 63.

  Further, when the second punch 23 moves downward while pressing the axial center portion on the other end side of the preliminary forged product W1, the second punch 23 is moved to the axial center portion on one end side of the preliminary forged product W1 as shown in FIG. A recess 71 is formed. At this time, the meat of the axial center portion on one end side flows to the outer periphery on one end side of the tooth profile 63, and the lacking thickness 64 of the tooth profile 63 is eliminated. Further, the second concave portion 72 is formed in the axial center portion of the other side of the preliminary forged product W <b> 1 by the pressing of the second punch 23. At this time, the meat of the axial center portion on the other end side flows to the outer periphery on the other end side of the preliminary forged product W1, and the flange portion 66 is formed.

  When the second punch 23 further moves downward as shown in FIG. 6A, the first concave portion 71 and the second concave portion 72 become deeper, and the flesh of the axial center portion on one end side and the other end side becomes Further, since the fluid further flows toward one end side and the other end side of the preliminary forged product W1, the length of the preliminary forged product W1 in the axial direction becomes longer. Further, a gap 74 is formed between the preliminary brim portion 61 of the preliminary forged product W1 and the punch guide 24, and the flow of meat in the axial direction is not hindered. A space 73 is formed away from the step portion 65 formed in the step.

  As shown in FIG. 7, when the forming process of the intermediate forged product W2 is completed, the first concave portion 71 and the second concave portion 72 are further deepened, and the meat on one end side and the other end side is the one end side of the preliminary forged product W1 and It flows to the other end side, and the length in the axial direction of the pre-forged product W1 becomes longer. Accordingly, the axial length of the tooth profile 63 is also longer than the axial length of the tooth forming portion 38. The flesh of the axial center part on the one end side flows to one end side of the pre-forged product W1, and there is no lacking wall on the one end side of the tooth profile 63. In addition, there is no lack of thickness on one end side of the cylindrical portion 77 that becomes the base of the tooth profile 63. A space 73 between the step portion 65 of the intermediate forged product forming die 33 and the flange portion 66 of the intermediate forged product W2 is formed to be larger.

  When the forming of the intermediate forged product W2 is completed, the knockout 35 is moved upward by the knockout pin 36, and the intermediate forged product W2 is taken out from the intermediate forged product forming die 33.

  The intermediate forged product W2 taken out by a conveying device (not shown) is placed so that the tooth shape 63 coincides with the sizing tooth die 57 of the forged product forming die 53. Subsequently, as shown in FIG. 4, the piercing stripper 44 of the movable die 42 is lowered, the piercing stripper 44 presses the other end side of the intermediate forged product W <b> 2, and the flange portion 66 comes into contact with the forged product forming die 53. At this time, the tooth profile 63 is sized by ironing. Next, the piercing punch 43 positioned so as to be movable back and forth in the piercing stripper 44 is lowered, the bottom 75 of the first concave portion 71 of the intermediate forged product W2 is punched to form a through hole 76, and the punched first concave portion 71 is formed. The bottom portion 75 is discharged from the discharge port 54, and the forged product W3 is completed. When the through hole 76 is formed, only the piercing punch 43 is lifted while the piercing stripper 44 presses the outer periphery of the forged product W3, and the fitting between the piercing punch 43 and the through hole 76 of the forged product W3 is released. . Thereafter, the piercing stripper 44 also moves upward. Then, the knockout 55 is moved upward by the knockout pin 56, and the forged product W3 is taken out from the forged product forming die 53.

  According to the method for forming a forged product of the present invention, a pre-forged product W1 having a diameter substantially equal to the diameter of the tip circle of the tooth profile 63 is formed on the intermediate forged product forming die 33 having the tooth forming portion 38 on the inner periphery. Since the press-fitting is performed from one end side in the axial direction, the meat of the pre-forged product W1 hardly flows in the radial direction. That is, the frictional force in the radial direction between the meat of the preliminary forged product W1 and the tooth forming portion 38 of the intermediate forged product forming die 33 is reduced, and the tooth tip does not become thin. On the other hand, frictional force in the axial direction is generated between the meat of the pre-forged product W1 and the tooth forming portion 38 of the intermediate forged product forming die 33, and it is easy to form a thin wall on one end side of the tooth profile 63. The axial part of one end side is pressed with the 1st punch 34, the 1st recessed part 71 is shape | molded in the one end side of the axial center part of the preliminary forging product W1, and the flesh of the one end side of an axial center part is the axis line of the tooth profile 63 Since it can be made to flow to the outer periphery on one end side in the direction, it is possible to prevent a lack of thickness from occurring on one end side of the tooth profile 63.

  Further, since a gap 74 is formed between the preliminary brim portion 61 of the preliminary forged product W1 and the punch guide 24, and the flow of meat in the axial direction is not hindered, the intermediate forging is completed when the intermediate forged product forming step is completed. A space 73 is formed between the intermediate forging product forming die 33 having the flange portion 66 of the product W2 and the tooth forming shape portion 38. That is, since the flow of meat is not suppressed, the load on the intermediate forging product forming die 33 can be reduced.

  In the embodiment of the present invention, an example of a helical gear is given as an example of the tooth profile, but a spur gear or other gear shape may be used.

It is a cross-sectional top view showing the manufacturing process of the forged product of this invention. It is a cross-sectional top view showing the preliminary forging product formation process which shape | molds the preliminary forging product of this invention. It is a cross-sectional top view showing the intermediate forging product formation process which shape | molds the intermediate forging product which shape | molded the tooth profile on the outer periphery of this invention. It is a cross-sectional top view showing the piercing process which shape | molds the forge product which has a through-hole in the axial center part of this invention. It is a cross-sectional top view showing the 1st step and the 2nd step in the intermediate forging product formation process of the present invention. It is a cross-sectional top view showing the 3rd step and the 4th step in the intermediate forging product formation process of this invention. It is a cross-sectional top view showing the time of completion in the intermediate forging product formation process of this invention.

33 Intermediate forging product forming die 34 First punch 38 Tooth forming portion 63 Tooth shape 71 First recess 73 Space 75 Bottom of first recess 76 Through hole W1 Pre-forged product W2 Intermediate forged product W3 Forged product

Claims (4)

In a molding method of molding a forged product (W3) having a tooth profile (63) on the outer periphery and a through hole (76) on the axial center,
The intermediate forging product forming die (33) having the tooth forming shape portion (38) on the inner periphery, the auxiliary flange portion (61) on the other end side outer periphery, and having a diameter substantially the same as the tip diameter of the tooth shape (63). At the same time as forming the tooth profile (63) on the outer periphery of the preliminary forged product (W1) by press-fitting the preliminary forged product (W1) from one end side in the axial direction of the preliminary forged product (W1),
A shaft on one end of the pre-forged product (W1) is pressed by a first punch (34) and a first recess (71) is formed on the shaft on the one end. An intermediate forged product (W2) having a collar portion (66) formed with a tooth profile (63) is formed by allowing the flesh of the core portion to flow to the outer periphery on one end side in the axial direction of the tooth profile (63). Intermediate forging in which a space (73) is formed between the flange portion (66) of the intermediate forged product (W2) and the intermediate forged product forming die (33) having the tooth forming shape portion (38) at the completion of molding of Product molding process,
A piercing process for forming a forged product (W3) by punching the bottom (75) of the first recess (71) of the intermediate forged product (W2) to form a through hole (76). Product molding method.   The method of forming a forged product according to claim 1, wherein the tooth profile (63) has a helical shape. In a molding method of molding a forged product (W3) having a tooth profile (63) on the outer periphery and a through hole (76) on the axial center,
A pre-forged product (W1) having the same diameter as the tip diameter of the tooth profile (63) is added to the intermediate forged product forming die (33) having the tooth forming portion (38) on the inner periphery. After press-fitting from one end side in the direction to form a tooth profile (63) on the outer periphery of the pre-forged product (W1) and one end side of the pre-forged product (W1) abuts on the first punch (34),
Further, by pressing the axial center portion on one end side of the pre-forged product (W1) with the first punch (34) and forming the first concave portion (71) on the axial center portion on the one end side, The flesh of the shaft center portion is caused to flow to the outer periphery on one end side in the axial direction of the tooth profile (63) to form the tooth profile (63), and the other end side of the preliminary forged product (W1) is pressed by the second punch (23). The second recessed portion (72) is formed in the shaft center portion, the other end side end surface of the second recessed portion (72) does not contact the movable mold (2), and the meat of the shaft center portion on the other end side is An intermediate forging product forming step for forming an intermediate forged product (W2) by flowing to the outer periphery on the other end side of the preliminary forged product (W1);
By the bottom of the first recess of the intermediate forgings (W2) (71) (75) the punched by forming a through hole (76), the piercing forming step of forming a forged product (W3), was closed ,
At the completion of the intermediate forging product forming step of forming the intermediate forged product (W2) having the flange portion (66) from the preliminary forged product (W1) having the preliminary flange portion (61) on the outer periphery on the other end side, the intermediate A forging product forming method characterized in that a space (73) is formed between a flange (66) of the forging product (W2) and an intermediate forging product forming die (33) having the tooth forming shape portion (38). . The method of forming a forged product according to claim 3, wherein the tooth profile (63) has a helical shape.

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