JP4471814B2 - Helical gear forging machine - Google Patents

Description

  The present invention relates to a forging apparatus for forming a helical gear having helical helical teeth on the outer periphery.

  Conventionally, when forming helical gears with helical helical teeth on the outer periphery, after forging a disk-shaped or ring-shaped forged product from the material in advance, it is applied to the outer periphery of the forged product by cutting such as gear shaving or hob. It has often been practiced to form helical gears by forming helical teeth.

  In recent years, however, forging technology has made it possible to form helical teeth by forging and eliminate cutting. Such a helical gear forging and forming apparatus and its forming method will be described with reference to FIGS.

  FIG. 6 shows a forging apparatus 110 before forging, which includes a movable mold 111 and a fixed mold 121. In the fixed die 121, a die 122 having a helical tooth die 123 for forming the helical teeth 102 on the inner periphery thereof and a die holder 127 arranged on the outer peripheral side of the die 122 are integrally fixed by shrink fitting. On the inner peripheral side of the die 122, a counter pin 134 having counter teeth 135 screwed to the tooth mold 123 and movable in the axial direction is disposed. A sculpture space 126 is defined between the counter pin 134 and the inner periphery of the die 122. In the movable mold 111, a punch 112 is arranged along the axis of the fixed mold 121, and a punch tooth 115 that is screwed with the tooth mold 123 of the die 122 is formed on the outer periphery of the tip of the punch 112. The movable mold 111 can advance and retreat with respect to the fixed mold 121.

  When the helical gear W101 is formed by the forging apparatus 110, the material W100 is put into the mold engraving space 126 of the fixed mold 121 in a state where the movable mold 111 is kept on standby, and then the movable mold 111 is lowered. Then, after the punch teeth 115 of the punch 112 abut on the tooth mold 123 of the die 122, the punch 112 is screwed into the die 122, and the material W100 is axially positioned between the punch 112 and the counter pin 134 as shown in FIG. Pressed. At this time, the material W100 is expanded in diameter toward the tooth mold 123 side of the die 122, the helical tooth 102 is formed, and the helical gear W101 is formed. Thereafter, as shown in FIG. 8, the counter pin 134 is raised, and the helical gear W <b> 101 is taken out from the die 122 while rotating along the tooth mold 123 of the die 122 integrally with the counter pin 134, thereby forming the helical gear W <b> 101. Is completed.

  When the helical gear W101 is formed using the forging apparatus 110 as described above, the helical teeth 102 can be formed by forging, and there is an advantage that cutting can be reduced.

  However, since the helical gear W101 forged and formed in this way is taken out while rotating along the helical tooth mold 123 when taken out from the die 122, a resistance force is applied to the helical tooth 102, and the helical gear W101 is taken out from the die 122. When W101 is taken out, the helical tooth 102 may be deformed and the tooth profile accuracy may be lowered. In particular, when the torsion angle of the tooth mold 123 of the die 122 is large, it is conceivable that the resistance force at the time of taking out increases and the tooth profile accuracy is remarkably lowered and falls outside the allowable range.

  Further, the resistance force when the helical gear W101 is taken out is also applied to the tooth mold 123 of the die 122. For this reason, the tooth mold 123 may be damaged by a load applied to the tooth mold 123 at the time of removal, and the die life of the die 122 may be shortened.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a helical gear forging device that can solve the above-described problems, can form a helical gear having helical teeth with high tooth profile accuracy, and has a long die life.
JP-A-60-115341

  The problem to be solved is that when a helical gear is formed by forging, a resistance force is applied to the helical tooth when the helical gear is removed from the forging apparatus, and the helical tooth is deformed when the helical gear is removed from the forging apparatus. As a result, the tooth profile accuracy is lowered, and when the helical gear is taken out from the forging apparatus, a load is applied to the tooth mold of the forging apparatus, and the die life is reduced.

  Accordingly, an object of the present invention is to provide a helical gear forging device that can form a helical gear having helical teeth with high tooth profile accuracy and has a long die life.

A tooth mold having a forming tooth portion for forming helical teeth of a helical gear on the inner periphery, a lower holder disposed on the outer periphery side of the tooth mold, a lower die for holding the tooth mold, and inner peripheries of the lower die and the tooth mold A fixed die having a ring-shaped counter punch that has a material arranged on the side and has an outer diameter smaller than the inner diameter of the tooth die, and a buffer mechanism that supports the tooth die so as to be movable in the axial direction; In a helical gear forging apparatus comprising a movable mold having an upper mold capable of moving forward and backward, the tooth mold has an outer peripheral taper whose outer periphery gradually decreases in diameter toward the movable mold, and the upper mold has an inner periphery thereof. A helical gear forging apparatus characterized by having an inner circumferential taper that gradually increases in diameter toward the fixed mold side, and only the tooth mold can be reduced inward by the upper mold.

According to the helical gear forging and forming apparatus according to the features of the present invention, a tooth mold having a forming tooth portion for forming helical teeth of the helical gear on the inner periphery, a lower holder disposed on the outer peripheral side of the tooth mold, and a tooth mold A lower die holding the ring, a material placed on the inner periphery of the lower die and the tooth mold, a ring-shaped counter punch having an outer diameter smaller than the inner diameter of the tooth mold, and the tooth mold moved in the axial direction A fixed mold having a buffer mechanism for holding the movable mold and a movable mold having an upper mold capable of moving forward and backward with respect to the fixed mold, and the tooth mold has an outer peripheral taper whose outer diameter gradually becomes smaller toward the movable mold. The upper die has an inner peripheral taper whose inner circumference gradually increases in diameter toward the fixed die side, and the tooth die can be reduced inward by the upper die, so that helical teeth of the helical gear are provided on the inner circumference. Has a molded tooth part to be molded and has a diameter larger than the outer diameter of the desired helical gear The first step to arrange the material on the inner circumference side of the tooth mold having the inner diameter, and the inner circumference necessary for forming the outer diameter shape of the desired helical gear by the load from the radial direction to the inner circumference side of the tooth mold The second step of reducing the diameter to the shape, and the tooth mold is pressed against the upper mold, and the contraction of the buffer mechanism causes the tooth mold and the upper mold to move together in the opposite upper mold direction to form a helical gear with helical teeth formed. Realized a molding method consisting of the third step and the fourth step of releasing the helical gear with the tooth mold returning to the dimension before diameter reduction, releasing the load from the radial direction on the tooth mold. When the helical gear after molding is taken out from the tooth mold, the tooth mold is expanded to the outer peripheral side, so the resistance force from the tooth mold on the helical tooth can be reduced, and a helical gear with high tooth profile accuracy can be obtained. Can be formed. Furthermore, since the resistance force applied to the tooth mold is reduced, the mold life of the tooth mold can be improved.

  Embodiments of the present invention will be described below on the basis of preferred embodiments of the present invention shown in the accompanying drawings.

  FIG. 1 shows an embodiment of a helical gear forging and forming apparatus according to an embodiment of the present invention. FIG. 1A is a cross-sectional front view showing a material before molding, and FIG. 2 is a partial sectional front view showing a state before forming a helical gear, FIG. 3 is a left sectional view showing an initial stage of formation, a right half is a partial sectional front view showing a second stage of formation, and FIG. FIG. 5 is a partial cross-sectional front view showing the final stage, FIG. 5 is a partial cross-sectional front view showing the initial stage of extraction, and the right half is the final stage of extraction.

  A helical gear forging device and a forging method according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows a cylindrical material W0 (FIG. 1A) before formation and a helical gear W1 (FIG. 1A) formed using a forging apparatus 10 according to an embodiment of the present invention. To express. The helical gear W1 has helical helical teeth 2 on the outer periphery, has concave portions 3 and 3 that are recessed near the center of both end faces, and has a through hole 4 that penetrates in the radial center.

  First, a helical gear forging apparatus according to an embodiment of the present invention will be described with reference to FIG. Reference numeral 10 denotes a forging apparatus, which includes a movable mold 11 and a fixed mold 21.

  The fixed die 21 includes a tooth die 22 having a forming tooth portion 24 for forming the helical tooth 2 of the helical gear W1 on the inner periphery, a lower holder 45 disposed on the outer peripheral side of the tooth die 22, and an inner periphery of the lower holder 45. It has a lower die 28 on which the tooth mold 22 is placed, and a die 32 on which the lower holder 45 and the lower die 28 are placed. A counter punch 34 is disposed on the inner peripheral side of the tooth mold 22, the lower die 28 and the die 32, and a mandrel 38 is disposed on the inner periphery of the counter punch 34. A die holder 33 is disposed on the outer periphery of the die 32, and the die holder 33 is placed on a guide 37. A plurality of pins 44 are disposed inside the guide 37, and a hydraulic cylinder 39 serving as a buffer mechanism is disposed below the guide 37.

  The forging apparatus 10 will be described in more detail. The tooth mold 22 has an outer peripheral taper 23 whose outer periphery gradually becomes smaller in diameter toward the movable mold 11, and a small opening 26 is formed on one movable mold 11 side and a large opening 27 is formed on the other. A step portion 25 is formed inside the large opening 27, and a molding tooth portion 24 is formed on the inner periphery of the step portion 25. The inner diameter of the formed tooth portion 24 is slightly larger than the outer diameter of the helical gear. The lower die 28 includes a cylindrical portion 29 and a protruding portion 30 protruding from the cylindrical portion 29 toward the movable mold 11, and the protruding portion 30 is in contact with the step portion 25 on the inner periphery of the large opening 27 of the tooth mold 22. It is inserted in. The counter punch 34 has a ring shape having an outer diameter smaller than the inner diameter of the tooth die 22 and is placed on the pin 44 and the guide 37 and can move in the axial direction, and the concave portion 3 of the helical gear W1 is formed at the upper end thereof. A pressure receiving portion 35 having a convex end portion 36 is formed. A sculpture space 50 is formed between the tooth mold 22, the lower die 28, the counter punch 34, and the mandrel 38. The hydraulic cylinder 39 is provided with a pipe 43 connected to a hydraulic pump (not shown), a hydraulic chamber 42 continuous with the pipe 43, a piston 40 accommodated in the hydraulic chamber 42, and a guide projecting upward from the piston 40. And a piston rod 41 inserted through a hole 37 a formed in 37. The die 32 is supported by the piston rod 41 and is movable in the axial direction. Further, a fixing ring 31 is disposed above the die 32 and the die holder 33 and restricts the movement of the die 32 in the axial direction.

  The movable mold 11 is disposed so as to be able to advance and retract on the same axis with respect to the fixed mold 21. A punch 13 is disposed along the axis of the movable mold 11, and a clamping holder 14 is disposed on the outer periphery of the punch 13. The punch 13 and the clamping holder 14 constitute an upper mold 12. At the lower end of the punch 13, a pressing portion 15 having a convex end portion 16 for forming the concave portion 3 of the helical gear W1 is formed. The tightening holder 14 has an inner circumferential taper 17 whose inner circumference gradually increases in diameter toward the fixed mold 21 and has the same inclination as the outer circumferential taper 23 of the tooth mold 22.

  Next, a method for forming the helical gear W1 with the forging apparatus 10 will be described. The movable die 11 is placed on standby in advance, and the cylindrical material W0 is placed in the die carving space 50 of the fixed die 21 in a state where the die 32 of the fixed die 21 is disposed at the upper end position where it abuts against the fixing ring 31 as shown in FIG. It is loaded and placed on the counter punch 34. At this time, the inner diameter of the tooth mold 22 is larger than the inner diameter of the lower die 28. Subsequently, the movable mold 11 is lowered. When the inner peripheral taper 17 of the tightening holder 14 contacts the outer peripheral taper 23 of the tooth mold 22 and the inner peripheral taper 17 moves along the outer peripheral taper 23, the tooth mold 22 is moved to the inner peripheral side as shown in the left half of FIG. When the load in the radial direction is received, the diameter is gradually reduced, and the inner diameter of the tooth mold 22 becomes the same as the inner diameter of the lower die 28. Then, as shown in the right half of FIG. Abuts on the material W0. Continuously, the movable die 11 is further lowered, and as shown in FIG. 4, the tooth die 22 has an inner peripheral shape substantially the same as the outer diameter shape of the helical gear W1 in order to form the desired outer diameter shape of the helical gear W1. In such a state that the diameter is reduced, the clamp holder 14 is lowered together with the fastening holder 14. At this time, the raw material W0 is pressed in the axial direction between the punch 13 and the counter punch 34, and the concave portions 3 and 3 are formed at both ends of the raw material W0 by the convex end portions 36 and 16, and at the same time, the diameter is expanded in the outer peripheral direction. Thus, the helical tooth 2 is formed by the forming tooth portion 24 of the tooth mold 22, and the helical gear W1 is completed.

  Next, when the upward movement of the movable die 11 is started, the die 32 is raised by the hydraulic cylinder 39, and the helical gear W1 is integrated with the tooth die 22, the lower die 28, and the lower holder 45 upward. The helical gear W <b> 1 is started to be taken out from the tooth mold 22 by moving, but in the initial stage of this taking out, the die 32 moves until it abuts against the fixing ring 31. Then, as shown in the left half of FIG. 5, when the clamping holder 14 of the movable mold 11 is continuously retracted upward, the tooth mold 22 is released from the radial load on the inner peripheral side, and the dimension before the diameter reduction is achieved. Return to. In this state, the counter punch 34 is continuously pushed and raised by the pin 44, and the helical gear W1 rises integrally with the counter punch 34, and as shown in the right half of FIG. To complete the formation of the helical gear W1.

According to the helical gear forging and forming apparatus 10, the tooth die 22 having the forming tooth portion 24 for forming the helical tooth 2 of the helical gear 1 on the inner periphery, and the lower holder 45 disposed on the outer peripheral side of the tooth die 22, The lower die 28 for holding the tooth mold 22, and the ring-shaped counter punch 34 that is disposed on the inner peripheral side of the lower die 28 and the tooth mold 22 and has an outer diameter smaller than the inner diameter of the tooth mold. And a fixed mold 21 including a hydraulic cylinder 39 that is a buffer mechanism that supports the tooth mold 22 so as to be movable in the axial direction, and a movable mold 11 including an upper mold 12 that can be advanced and retracted relative to the fixed mold 21. The tooth mold 22 has an outer peripheral taper 23 whose outer periphery gradually decreases in diameter toward the movable mold 11, and the upper mold 12 has an inner peripheral taper 17 whose inner periphery gradually increases in diameter toward the fixed mold 21. The tooth mold 22 is contracted inward by the upper mold 12. Since possible, by forming a helical teeth 2 of the helical gears on the inner periphery, placing the material W0 on the inner circumferential side of the tooth mold 22 having a molding teeth 24 having a larger diameter inner diameter than the outer diameter of the helical gears W1 A first step, a second step of reducing the diameter of the tooth mold 22 to an inner peripheral shape necessary for forming a desired outer diameter shape of the helical gear W1 by a load from the radial direction toward the inner peripheral side, and a tooth mold When the upper die 12 is pressed and the hydraulic cylinder 39, which serves as a buffer mechanism, contracts, the tooth die 22 and the upper die 12 move together in the anti-upper die direction to form a helical gear W1 in which the helical teeth 2 are formed. Forging comprising three steps and a fourth step in which the load from the radial direction on the inner peripheral side of the tooth mold 22 is released and the helical gear W1 is taken out in a state where the tooth mold 22 has returned to the dimension before the diameter reduction. since the forming method can be realized, after molding from the tooth die 22 To remove the helical gears W1, since dental cast 22 is expanded toward the outer periphery, it is possible to reduce the resistance of the tooth die 22 acting on the helical teeth 2. Further, the resistance from the helical gear W1 related to the tooth mold 22 can also be reduced.

(A) is the raw material before shaping | molding, (A) is a cross-sectional front view showing the helical gear after shaping | molding. It is a partial section front view showing the state before forming a helical gear with the forge forming device by the example of the present invention. FIG. 2 is a partial cross-sectional front view showing a helical gear forging device according to an embodiment of the present invention, in which the left half portion represents an initial stage of formation and the right half portion represents a second stage of formation. It is a partial cross-sectional front view showing the forge forming apparatus of the helical gear by the Example of this invention, and showing the final stage of formation. In the helical gear forging apparatus according to the embodiment of the present invention, the left half is a partial sectional front view showing the initial stage of extraction and the right half is the final stage of extraction. It is a fragmentary sectional front view showing the state before forming a helical gear with the conventional forging apparatus. It is a fragmentary sectional front view showing the state after forming a helical gear with the conventional forging apparatus. It is a fragmentary sectional front view showing a state when a helical gear is taken out with a conventional forging apparatus.

Explanation of symbols

2 Helical teeth 11 Movable mold 12 Upper mold 17 Inner circumference taper 21 Fixed mold 22 Tooth mold 23 Outer circumference taper 24 Molded tooth part 28 Lower die 34 Counter punch 39 Buffer mechanism

Claims (1)

A tooth mold (22) having a formed tooth portion (24) for forming the helical tooth (2) of the helical gear on the inner periphery, a lower holder (45) disposed on the outer periphery side of the tooth mold (22), and A lower die (28) for holding the tooth mold (22), a material (W0) disposed on the inner periphery side of the lower die (28) and the tooth mold (22), and the tooth mold (22) A fixed die (21) comprising a ring-shaped counter punch (34) having an outer diameter smaller than the inner diameter of the ring, and a buffer mechanism (39) for supporting the tooth die (22) so as to be movable in the axial direction; In the helical gear forging apparatus comprising a movable mold (11) having an upper mold (12) capable of moving forward and backward with respect to the fixed mold (21), the outer periphery of the tooth mold (22) is on the movable mold (11) side. The outer taper (23), which gradually decreases in diameter toward the Toward the fixed mold (21) side has an inner periphery tapered (17) which gradually becomes large, and characterized in that only the tooth die (22) can be reduced in diameter on the inside by the upper mold (12) Helical gear forging equipment.

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