JP4107793B2 - Gear forming method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gear forming method and apparatus for forming a gear by hot forging or cold forging.
[0002]
[Prior art]
For example, a two-stage gear having a straight tooth profile portion and a helical tooth profile portion is used in a transmission of an automobile including a synchro mechanism. In order to manufacture this two-stage gear, a method of manufacturing a two-stage gear by forming a helical tooth profile by cutting with a cutter on a molded body in which a straight tooth profile is formed by hot forging. There is.
[0003]
In addition, as another method, a method of manufacturing a two-stage gear by joining a molded body having a straight tooth profile portion and a molded body formed by cutting with a cutter to form a helical tooth profile portion by welding or the like. Is mentioned.
[0004]
[Problems to be solved by the invention]
However, in the manufacturing method according to the prior art, when a helical tooth profile is cut by a cutter with respect to a molded object in which a straight tooth profile is formed by hot forging, it is generated in the molded object. Forging lines (fiber structure flow due to plastic deformation) may be cut by the cutter. Thereby, while the intensity | strength of the manufactured gear falls remarkably, there exists a malfunction that a material yield deteriorates with the chip generated at the time of cutting.
[0005]
In addition, when a molded body having a straight tooth profile and a molded body having a helical tooth profile formed by cutting with a cutter are joined by welding or the like, complicated welding operations must be performed. Therefore, it has been pointed out that the manufacturing process becomes complicated and the manufacturing cost increases.
[0006]
The present invention has been made in consideration of such problems, and manufactures a gear having a straight tooth profile portion and a helical tooth profile portion all at once without performing machining or welding work with a cutter or the like. Thus, it is possible to reliably ensure the strength of the gear, improve the material yield, simplify the manufacturing process, and reduce the manufacturing cost. An object is to provide such a device.
[0007]
[Means for Solving the Problems]
According to the first aspect of the present invention, a gear material is placed on one end of a lower punch having external teeth, a mandrel is inserted into the gear material, and the gear material is pressed by an insert punch sleeve and an upper punch. And releasing the pressing force against the gear material by the insert punch sleeve to separate the insert punch sleeve from the gear material, and further pressing the gear material by the upper punch, thereby engaging the external teeth. A second step of forming the tooth profile of the gear by flowing the gear material into the first tooth forming profile formed on the die and the second tooth forming profile formed on the upper punch, and a knockout punch And a third step of releasing the gear from the die by rotating the lower punch under the action of the above. In this case, a helical tooth profile is formed on the gear material by the first tooth forming profile, and a straight tooth profile is formed on the gear material by the second tooth forming profile.
[0008]
The present invention also provides a center guide, a knockout punch, a lower punch that is rotatably disposed on the outer peripheral surface of the center guide, and a first tooth forming shape that meshes with external teeth formed on the lower punch. A die having a portion, a mandrel so as to face the die, an insert punch sleeve fitted to the mandrel, and an outer peripheral surface of the insert punch sleeve, and a second tooth forming shape portion The knockout punch, the mandrel, and the upper punch are connected to the first drive mechanism, the second drive mechanism, and the third drive mechanism, respectively, and the mandrel is provided inside the gear blank. While the gear is pressed, the gear blank is pressed by the insert punch sleeve and the upper punch, thereby forming the tooth profile portion of the gear. After the mandrel, the insert punch sleeve, and the upper punch are integrally separated from the gear under the driving action of the driving mechanism and the third driving mechanism, the driving mechanism is driven by the first driving mechanism. The lower punch is rotated and moved by moving the knockout punch to release the gear from the die.
[0009]
According to the present invention, since the first tooth forming portion is formed in a helical shape and the second tooth forming shape portion is formed in a straight shape, the helical tooth shape portion can be formed from the gear material without performing machining or welding work with a cutter or the like. A two-stage gear having a straight tooth profile can be manufactured all at once. Thereby, it can prevent cutting the forge line produced | generated by a forge molded object accidentally, and a welding operation can be avoided. Therefore, it is possible to reliably ensure the strength of the gear after molding, and it is possible to avoid the generation of chips during molding of the gear, thereby improving the material yield and simplifying the gear manufacturing process. And manufacturing costs can be reduced.
[0010]
Furthermore, when the gear is released from the die after the gear is formed from the gear material, the insert punch sleeve is fitted to the mandrel for centering the gear material, so that the second drive mechanism and the third By driving the drive mechanisms synchronously, the mandrel, the insert punch sleeve and the upper punch can be integrally separated from the gear. Therefore, for example, there is no need to provide a dedicated pin for moving the mandrel or a drive mechanism for moving the pin. For this reason, the gear is formed only by installing three drive mechanisms for moving the insert punch sleeve, the upper punch, and the knockout punch, respectively, until the gear is formed from the gear material and released from the die. be able to.
[0011]
In the gear forming apparatus for carrying out the above-described gear forming method, the upper punch is fitted with a holder in which a pin insertion port is formed, a pin is implanted in the die, and the pin is the pin. The upper punch and the die are connected and rotated by being inserted into the insertion port, the first tooth forming portion is formed in a helical shape, and the second tooth forming shape portion is formed in a straight shape. Preferably formed. That is, since the die and the upper punch are connected via the pin, the die and the upper punch can rotate in synchronization. Accordingly, when the gear blank is pressed by the upper punch, the gear material flesh flows into the helical first tooth forming portion, presses the first tooth forming portion, and the die rotates. Thereby, the meat of the gear material can surely flow in the straight second tooth forming portion formed in the upper punch, and the straight tooth portion can be formed.
[0012]
Furthermore, it is preferable that the angle θ of the first tooth forming portion with respect to the axial direction of the teeth is set within a range of 30 ° <θ <45 °. When the angle θ is increased within the range of 30 ° <θ <45 °, the contact area between the teeth of the formed gear can be increased as much as possible. Thereby, for example, when a predetermined load is applied to the gear, the load applied per unit area is smaller when the contact area between the teeth is larger, so the load applied to the teeth constituting the gear is reduced. As a result, the life of the gear can be extended and the generation of meshing noise between teeth can be reduced as much as possible. In addition, since the load applied to the teeth constituting the gears is reduced, the reduction in the strength of the teeth can be prevented. For example, when the gears molded according to the present invention are used in an automobile transmission, the gear width is reduced. As a result, the transmission itself can be made compact. That is, the angle θ of the first tooth forming portion with respect to the axial direction of the teeth can be set to a desired angle within a range of 30 ° <θ <45 ° according to the purpose, so that the degree of freedom in design is improved.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The gear forming method according to the present invention will be described in detail below with reference to the accompanying FIGS. 1 to 9A and 9B with reference to preferred embodiments in relation to the gear forming apparatus. In addition, although the use is not limited for this gear shaping | molding apparatus, For example, it is preferable when it is used in order to shape | mold the two-stage gear used for the transmission of the motor vehicle provided with a synchro mechanism.
[0014]
A gear forming apparatus 10 according to the present embodiment is for forging a ring-shaped gear blank 12 (see FIG. 9A) to form a two-stage gear 130 (see FIG. 9B), as shown in FIG. In addition, a fixed portion 14 and a movable portion 16 are provided. The fixing portion 14 includes a gantry 18, and the gantry 18 has a first recess 20 formed in a substantially central portion thereof, and a substantially rectangular shape formed radially outward with respect to the first recess 20. A second recess 22 is included. A substantially cylindrical center guide 24 is erected in the first recess 20 so as to extend upward from the first recess 20 in FIG. 1, and a claw portion so as to surround the center guide 24. A first holder 30 composed of a main body portion 26 and a main body portion 28 is fixed on a first annular convex portion 32 formed between the first concave portion 20 and the second concave portion 22. The center guide 24 abuts its circumferential surface on the claw portion 26, and a gap portion 34 that circulates the center guide 24 is formed between the center guide 24 and the main body portion 28.
[0015]
A plurality of substantially cylindrical knockout punches 36 are provided concentrically so as to pass through the gantry 18, the claw portion 26 and the gap portion 34 so as to surround the center guide 24. The knockout punch 36 is centered by the center guide 24, and an annular spacer 38 mounted on the claw portion 26 of the first holder 30 is fixed to one end of the knockout punch 36, and The other end of the knockout punch 36 is connected to a first drive mechanism (not shown) at the bottom in FIG. Further, on the spacer 38, a lower punch 40 that can rotate the outer peripheral surface of the center guide 24 is placed. In FIG. 1, the lower punch 40 has a lower portion formed as a thick portion 42, and then an upper portion formed through a tapered portion 44 as a thin portion 46. Helical external teeth 48 are engraved on the outer peripheral portion of the distal end of the thin portion 46. Therefore, the knockout punch 36 can move up and down in the vertical direction under the action of the first drive mechanism, and the lower punch 40 can also move up and down in the vertical direction via the spacer 38.
[0016]
As shown in FIG. 2, gas dampers 54 spaced apart from each other by a predetermined distance from the axis of the center guide 24 are disposed at the four corners of the second recess 22. A disc-shaped set plate 58 is fixed to the rod 56 of the gas damper 54 (see FIG. 1). As understood from FIG. 1, a coil spring 64 is interposed so as to surround the first annular protrusion 32, the first holder 30, and the knockout punch 36.
[0017]
Further, on the second annular convex portion 66 formed radially outward of the second concave portion 22, an annular bulging portion 68 is provided so as to cover the gas damper 54 and the set plate 58. Two holders 70 are fixed. The outer peripheral surface 74 of the second holder 70 protrudes outward in the radial direction from the outer peripheral surface 72 of the gantry 18.
[0018]
Further, an annular guide member 78 is attached to the annular flat portion 76 formed on the upper portion of the set plate 58, and a spacer 80 surrounding the lower punch 40 is rotatably mounted on the guide member 78. Placed. A die 84 is fixed to the upper portion of the spacer 80, and a concave portion 82 having a tapered portion 81 is formed at the center upper portion of the die 84. A synchronous pin 91 is implanted along the axis in FIG. 1 and directed upward in the outer peripheral portion of the upper flat surface 85 of the die 84 and communicates with the concave portion 82 to form a helical tooth profile of the two-stage gear 130. A helical tooth forming portion 86 for molding the portion 132 (see FIG. 9B) is formed (see FIG. 3). As shown in FIG. 3, the teeth 87 of the helical tooth forming portion 86 are engraved over the entire circumference at equal intervals and inclined by an angle θ with respect to the axial direction. In the present embodiment, the angle θ is preferably set in a range of 30 ° <θ <45 °.
[0019]
An annular third holder 88 is fixed to the upper portion of the second holder 70, and is provided on the die 84 so as to be directed radially outward of the die 84 by the elastic force of the gas damper 54. The second stopper portion 92 is directed radially inward of the third holder 88 and engages with a first stopper portion 90 provided on the third holder 88. A fourth holder 93 is fitted to the outer peripheral surfaces 72, 74, and 89 of the gantry 18, the second holder 70, and the third holder 88.
[0020]
As shown in FIG. 1, the movable portion 16 includes a rod 94, a substantially cylindrical mandrel 96 fixed to a substantially central portion of one end portion of the rod 94, and an insert punch sleeve 98 fitted to the mandrel 96. And have. The mandrel 96 is for centering the gear material 12 when the gear material 12 is forged. The outer peripheral surface of the insert punch sleeve 98 includes a first straight portion 100 from below in FIG. 1 and a first tapered portion 102 inclined at a predetermined angle in a direction away from the first straight portion 100 with respect to the axis. A second linear portion 104 extending in the axial direction from the first tapered portion 102, and a second tapered portion 106 inclined at a predetermined angle in a direction away from the second linear portion 104 with respect to the axis. , And a third linear portion 108 extending in the axial direction from the second taper portion 106. Further, the other end of the rod 94 is connected to a second drive mechanism (not shown) in the upper part of FIG. Accordingly, the rod 94 can move up and down in the vertical direction under the action of the second drive mechanism.
[0021]
Further, a spacer 110 is disposed so as to surround the rod 94, and an annular upper punch 112 slidable on the outer peripheral surface of the insert punch sleeve 98 is provided on the bottom surface of the spacer 110. The inner peripheral surface of the upper punch 112 includes a fourth linear portion 114 from below in FIG. 1 and a third tapered portion 116 inclined at a predetermined angle in a direction away from the fourth linear portion 114 with respect to the axis. A fifth linear portion 118 extending in the axial direction from the third tapered portion 116, and a fourth tapered portion 120 inclined at a predetermined angle in a direction away from the fifth linear portion 118 with respect to the axis. A fifth tapered portion 122 that matches the shape of the tapered portion 81 formed in the concave portion 82 of the die 84 is formed on the outer periphery of the top end of the upper punch 112. As can be understood from FIG. 1, the first straight portion 100 formed on the insert punch sleeve 98, the fourth straight portion 114 formed on the upper punch 112, and the first straight portion 100 formed on the insert punch sleeve 98. The second straight portion 104 and the fifth straight portion 118 formed on the upper punch 112 are in contact with each other.
[0022]
Further, a straight tooth forming portion 136 for forming a straight tooth shape portion 134 (see FIG. 9B) of the two-stage gear 130 is engraved at the tip of the fourth straight portion 114 formed in the upper punch 112. (See FIG. 4). As shown in FIG. 4, the straight tooth profile forming portion 136 has a chamfer portion 138 at the tip, and is engraved at equal intervals in the axial direction over the entire circumference.
[0023]
A fifth holder 124 for supporting and fixing the upper punch 112 in the direction of the spacer 110 is fitted to the outer peripheral surface of the upper punch 112, and the outer peripheral surface of the spacer 110 is fitted to the spacer 110 and the fifth holder 124. A sixth holder 126 that is rotatable is mounted on the exterior. The fifth holder 124 is formed with a synchronization pin insertion port 127 so as to cut out a part of the outer peripheral surface of the fifth holder 124. The synchronization pin insertion port 127 faces the synchronization pin 91 planted in the die 84. The spacer 110 and the sixth holder 126 are connected to a third drive mechanism (not shown) in the upper part in FIG. Therefore, the spacer 110 and the sixth holder 126 are movable up and down in the vertical direction under the action of the third drive mechanism. That is, the upper punch 112 can slide vertically on the outer peripheral surface of the insert punch sleeve 98. The second drive mechanism (not shown) and the third drive mechanism (not shown) can be driven independently or synchronously.
[0024]
The gear forming apparatus 10 according to the present embodiment is basically configured as described above. Next, its operation and effect will be described in relation to the gear forming method.
[0025]
First, a second drive mechanism and a third drive mechanism (not shown) are driven in synchronization, and the movable portion 16 is separated from the fixed portion 14 as shown in FIG. Then, the ring-shaped gear material 12 (see FIG. 9A) is placed on the thin portion 46 of the lower punch 40. At this time, a part of the external teeth 48 engraved on the outer periphery of the tip of the thin portion 46 is engaged with a helical tooth forming portion 86 engraved on the inner periphery of the die 84.
[0026]
Thereafter, the second drive mechanism and the third drive mechanism (not shown) are driven in synchronization, and the movable part 16 is moved vertically downward to bring the movable part 16 into close contact with the fixed part 14. (See FIG. 5). In this case, the fifth taper portion 122 formed on the upper punch 112 abuts on the taper portion 81 formed in the concave portion 82 of the die 84, and the synchronization pin 91 implanted in the upper flat surface 85 of the die 84. Is inserted into the synchronization pin insertion slot 127 formed in the fifth holder 124, and the mandrel 96 is inserted into the gear blank 12. Moreover, the gear blank 12 is pressed vertically downward by the insert punch sleeve 98 and the upper punch 112. Thereby, the set plate 58, the spacer 80, and the die 84 are pressed vertically downward against the elastic force of the gas damper 54. Therefore, the engaging action of the second stopper portion 92 provided on the die 84 with respect to the first stopper portion 90 formed on the third holder 88 is released, and the first stopper portion 90 and the first stopper portion 90 are released. A first gap portion 128 is formed between the two stopper portions 92 (see FIG. 5). Further, since the lower punch 40 is rotatable on the outer peripheral surface of the center guide 24, the outer teeth 48 further mesh with the helical tooth forming portion 86 (see FIG. 5). At that time, a part of the meat of the gear blank 12 flows in the helical tooth forming portion 86.
[0027]
Next, the second drive mechanism (not shown) is driven to move the insert punch sleeve 98 vertically upward, and the third drive mechanism (not shown) is driven to further lower the upper punch 112 downward. Move in the direction. As a result, the pressing action of the insert punch sleeve 98 against the gear blank 12 is released, and a second gap 129 is formed between the gear blank 12 and the insert punch sleeve 98 (see FIG. 6). At the same time, against the elastic force of the gas damper 54, the set plate 58, the spacer 80, and the die 84 are further pressed vertically downward by the upper punch 112, and the first stopper portion 90 and the second stopper portion 92 The first gap portion 128 formed therebetween is expanded (see FIG. 6). At this time, the meat of the gear blank 12 further flows into the helical tooth forming portion 86. At that time, the gear blank 12 rotates the outer peripheral surface of the mandrel 96 in a predetermined direction by a predetermined angle, and the helical tooth forming portion 86 is engraved in a helical shape. The helical tooth forming portion 86 is pressed while spirally flowing in the helical tooth forming portion 86. That is, a helical force is applied to the die 84 in a direction away from the shaft, but since the die 84 is pressed vertically downward by the upper punch 112, the die 84 is The material 12 rotates in the direction of rotation by a predetermined angle. In other words, the die 84 and the spacer 80 fixed to the bottom surface of the die 84 integrally rotate on the guide member 78 about the axis in the rotation direction of the gear material 12 by a predetermined angle. Thereby, the helical tooth profile 132 of the two-stage gear 130 is formed (see FIG. 9B).
[0028]
Further, at this time, since the die 84 and the fifth holder 124 are integrally connected by the synchronization pin 91, the fifth holder 124 is rotated by rotating the die 84 by a predetermined angle in a predetermined direction. The upper punch 112 fitted to the fifth holder 124 and the sixth holder 126 that covers the fifth holder 124 rotate in synchronism with the die 84 integrally. Eventually, the meat of the gear blank 12 also flows into the straight tooth forming portion 136 carved on the inner periphery of the tip of the upper punch 112. Accordingly, the straight tooth forming portion 136 of the two-stage gear 130 is also formed (see FIG. 9B).
[0029]
Then, the second drive mechanism and the third drive mechanism (not shown) are driven in synchronization to separate the movable portion 16 from the fixed portion 14 (see FIG. 7). That is, the mandrel 96, the insert punch sleeve 98, and the upper punch 112 are integrally separated from the two-stage gear 130. Thus, the vertical downward pressure applied to the set plate 58, the spacer 80, and the die 84 is released against the elastic force of the gas damper 54, and the second stopper portion 92 of the die 84 is moved to the first position. 3 is engaged with the first stopper portion 90 of the holder 88 (see FIG. 7).
[0030]
Thereafter, the knockout punch 36 is moved vertically upward under the action of a first drive mechanism (not shown). At this time, the outer punch 48 rotates and moves vertically upward while the outer teeth 48 of the lower punch 40 mesh with the helical tooth forming portion 86 of the die 84 via the spacer 38 fixed to the knockout punch 36. At this time, the die 84 is returned by a predetermined angle about a shaft in a predetermined direction by the meshing of the helical tooth profile 132 of the formed two-stage gear 130 and the helical tooth forming profile 86. That is, the state before the gear material 12 is formed (the state shown in FIG. 1). As a result, the two-stage gear 130 is released from the die 84 (see FIG. 8).
[0031]
The two-stage gear 130 is conveyed to the next process by a conveying device (not shown), and finally machined to a predetermined size and shape to be completed as a product.
[0032]
【The invention's effect】
As described above, according to the present invention, a two-stage gear having a helical tooth profile portion and a straight tooth profile portion can be manufactured at once from a gear material without performing machining or welding work with a cutter or the like. . Thereby, it is possible to prevent the forged stream line generated in the forged molded body from being cut by mistake, and on the other hand, it is possible to avoid as much as possible the complicated welding work as in the prior art. Therefore, it is possible to reliably ensure the strength of the gear after molding, and it is possible to avoid the generation of chips during gear molding, thus improving the material yield and simplifying the manufacturing process. In addition, the manufacturing cost can be reduced.
[0033]
In addition, since the die and the upper punch are connected via a pin, the die and the upper punch can rotate in synchronization. Therefore, when the gear blank is pressed by the upper punch, the gear material flesh flows into the helical tooth forming portion, presses the helical tooth forming portion, and the die rotates. As a result, the gear material can reliably flow in the straight tooth forming portion formed in the upper punch, and the straight tooth portion can be formed.
[0034]
Further, when the gear is released from the die after the gear is formed from the gear material, the insert punch sleeve is fitted to the mandrel for centering the gear material, so the second drive mechanism and the third By driving the drive mechanisms synchronously, the mandrel, the insert punch sleeve and the upper punch can be integrally separated from the gear. Therefore, for example, there is no need to provide a dedicated pin for moving the mandrel or a drive mechanism for moving the pin. For this reason, the gear is formed only by installing three drive mechanisms for moving the insert punch sleeve, the upper punch, and the knockout punch, respectively, until the gear is formed from the gear material and released from the die. be able to.
[0035]
Furthermore, the angle θ with respect to the axial direction of the tooth of the helical tooth forming portion formed on the die is set to an angle within the range of 30 ° <θ <45 °, so the angle θ is 30 ° <θ <45 °. When it is increased within the range, the contact area between the teeth of the formed gear can be increased as much as possible. Thus, for example, when a predetermined load is applied to the gear, the load applied to the gear teeth is reduced because the load applied per unit area is smaller when the contact area between the teeth is larger. The service life of the gear can be increased, and the generation of meshing noise between teeth can be reduced as much as possible. In addition, since the load applied to the gear teeth can be reduced, a reduction in the strength of the teeth can be prevented.For example, when the gear formed according to the present invention is used in an automobile transmission, the gear width can be reduced, and thus The transmission itself is made compact. That is, the angle θ with respect to the axial direction of the tooth of the helical tooth forming portion can be set to a desired angle within a range of 30 ° <θ <45 ° according to the purpose, and thus a specific effect that design flexibility is improved is obtained. It is done.
[Brief description of the drawings]
FIG. 1 is a partially omitted longitudinal sectional view showing a gear forming apparatus according to the present embodiment.
FIG. 2 is an explanatory view taken along the line II-II in FIG.
3 is a partially omitted enlarged vertical cross-sectional explanatory view showing a die constituting the gear forming apparatus of FIG. 1. FIG.
4 is a partially omitted enlarged longitudinal sectional view showing a straight tooth forming portion engraved in an upper punch constituting the gear forming apparatus of FIG. 1. FIG.
5 is a partially omitted vertical cross-sectional explanatory view showing a state in which a gear material is pressed by an insert punch sleeve and an upper punch in the gear forming apparatus of FIG. 1. FIG.
6 is a partially omitted vertical cross-sectional explanatory view showing a state in which the gear blank is further pressed by an upper punch from the state shown in FIG. 5;
7 is a partially omitted vertical cross-sectional explanatory view showing a state in which the movable part is separated from the fixed part in the gear forming apparatus of FIG. 1;
8 is a partially omitted vertical cross-sectional explanatory view showing a state in which the two-stage gear after forging is released from the die in the gear forming apparatus of FIG. 1;
9A is a perspective view showing a gear blank, and FIG. 9B is a perspective view showing a two-stage gear after forging.
[Explanation of symbols]
10 ... Gear forming device 12 ... Gear material
24 ... Center guide 36 ... Knockout punch
40 ... lower punch 48 ... external teeth
86 ... Helical tooth forming part 87 ... Teeth
96 ... Mandrel 98 ... Insert punch sleeve
112 ... Upper punch 130 ... Double gear
132 ... Helical tooth profile 134 ... Straight tooth profile
136 ... Straight tooth forming part

Claims (6)

A first step of placing a gear material on one end of a lower punch having external teeth, inserting a mandrel into the gear material, and pressing the gear material with an insert punch sleeve and an upper punch;
The pressing force against the gear material by the insert punch sleeve is released to separate the insert punch sleeve from the gear material, and further press the gear material by the upper punch, whereby the outer teeth mesh with the die. A second step of shaping the gear tooth profile by flowing the gear material into the formed first tooth profile and the second tooth profile formed on the upper punch;
A third step of releasing the gear from the die by rotating the lower punch under the action of a knockout punch;
A gear forming method comprising: The gear forming method according to claim 1,
A gear tooth forming method, wherein a helical tooth profile portion is formed on the gear material by the first tooth forming shape portion, and a straight tooth shape portion is formed on the gear material by the second tooth forming shape portion. A center guide, a knockout punch, a lower punch rotatably disposed on an outer peripheral surface of the center guide, and a die having a first tooth forming shape portion meshing with external teeth formed on the lower punch. Prepared,
A mandrel, an insert punch sleeve that is fitted to the mandrel, and an upper punch that is slidable on the outer peripheral surface of the insert punch sleeve and is formed with a second tooth forming portion are provided so as to face the die. And
The knockout punch, the mandrel and the upper punch are connected to a first drive mechanism, a second drive mechanism and a third drive mechanism, respectively.
While the mandrel is inserted into the gear blank, the gear blank is pressed by the insert punch sleeve and the upper punch to form the tooth profile of the gear, and the second drive mechanism and the third drive The mandrel, the insert punch sleeve, and the upper punch are integrally separated from the gear under the driving action of the mechanism, and then the knockout punch is moved under the driving action of the first driving mechanism. A gear forming apparatus characterized in that a lower punch is rotated to release the gear from the die. The gear forming apparatus according to claim 3, wherein
A holder in which a pin insertion port is formed is fitted to the upper punch, and a pin is implanted in the die,
The gear forming apparatus, wherein the upper punch and the die are connected and rotated by inserting the pin into the pin insertion opening. In the gear forming apparatus according to claim 3 or 4,
The first tooth forming portion is formed in a helical shape,
The gear forming apparatus, wherein the second tooth forming portion is formed in a straight shape. In the gear forming device according to any one of claims 3 to 5,
An angle θ of the first tooth forming portion with respect to the axial direction of the teeth is in a range of 30 ° <θ <45 °.

Images