JP5573389B2 - Gear forming apparatus and method - Google Patents

Description

  The present invention relates to a gear forming apparatus for forming a gear having external teeth on an outer peripheral side portion and spline grooves on an inner peripheral side portion from an annular material.

  In forming a gear having external teeth, a method by cutting, rolling, or the like is generally used. For example, as disclosed in the gear forming apparatus of Patent Document 1, the gear is formed by cold forging. There is a way to do it. In this molding apparatus, when forming a gear having external teeth and internal teeth, the external teeth of the die are formed by pressing the material arranged in the space surrounded by the die, the support member and the mandrel with the external punch and the internal punch. The outer teeth are formed by the portion, and the inner teeth are formed by the inner tooth forming portion of the mandrel. Thereby, the external teeth and internal teeth of the gear are accurately formed with a small number of processing steps.

JP 2001-191143 A

  However, when the shape of the gear to be molded is a shape in which the thickness of the inner peripheral side portion is reduced with respect to the outer peripheral side portion, the outer teeth are formed on the outer peripheral side portion by the simple cold forging and the inner peripheral side. It is difficult to mold internal teeth in the part. That is, in this case, when molding the internal teeth, it is difficult to flow the material into the space portion where the thickness is reduced, and it is necessary to mold the internal teeth with an excessive pressure. Therefore, a part of the material flows in a gap formed between the mandrel, the inner punch, and the support member, and a burr (protrusion portion due to the material) is formed on the inner peripheral side of the gear. There is a risk that the service life of the molds such as the inner punch and the support member may be reduced.

  The present invention has been made in view of such conventional problems, and suppresses the pressurizing force necessary for molding, ensures the durability of the mold, and accurately molds a gear having external teeth and spline grooves. It is an object of the present invention to provide a gear forming apparatus and method that can be used.

The first invention is an apparatus for forming a gear having an external tooth on the outer peripheral side portion and a spline groove on the inner peripheral side portion whose thickness is smaller than that of the outer peripheral side portion from an annular material,
A die provided with an external tooth forming hole for forming the external tooth;
In a state where the lower end insertion portion is arranged in the through hole of the annular material, a mandrel provided with a punching blade for punching the spline groove in the annular material,
A punch that is disposed on the outer periphery of the mandrel, has an engagement tooth that engages the punching blade on the inner periphery, and pressurizes the upper surface of the annular material;
The spline groove is formed in the annular material together with the punching blade of the mandrel and has an engaging tooth that receives a load applied to the annular material from the punch and engages with the external tooth forming hole of the die. A die sleeve having a punching receiving blade for punching in the inner periphery,
An inner die having an insertion hole for inserting a lower end insertion portion of the mandrel in an inner peripheral portion, and having an engagement tooth that has the same shape as the punching blade of the mandrel and engages with the punching receiving blade of the die sleeve And
In the forging space surrounded by the die, the mandrel, the punch, the die sleeve and the inner die, the mandrel, the punch and the die are lowered, and a lower end insertion portion of the mandrel is inserted into the through hole of the annular material. The annular material is pressed between the punch, the die sleeve, and the inner die to form a gear shape having the external teeth, and the annular material is formed between the inner die and the punch. The mandrel is lowered in a state where the inner peripheral side portion is sandwiched, and the spline groove is punched in the inner peripheral side portion of the annular material by the punching blade of the mandrel and the punching receiving blade of the die sleeve. The gear forming apparatus is characterized in that it is configured (claim 1).

The second invention is a method of forming a gear having an external tooth on the outer peripheral side portion and a spline groove on the inner peripheral side portion whose thickness is smaller than that of the outer peripheral side portion from an annular material,
A die provided with an external tooth forming hole for forming the external tooth;
In a state where the lower end insertion portion is arranged in the through hole of the annular material, a mandrel provided with a punching blade for punching the spline groove in the annular material,
A punch that is disposed on the outer periphery of the mandrel, has an engagement tooth that engages the punching blade on the inner periphery, and pressurizes the upper surface of the annular material;
The spline groove is formed in the annular material together with the punching blade of the mandrel and has an engaging tooth that receives a load applied to the annular material from the punch and engages with the external tooth forming hole of the die. A die sleeve having a punching receiving blade for punching in the inner periphery,
An inner die having an insertion hole for inserting a lower end insertion portion of the mandrel in an inner peripheral portion, and having an engagement tooth that has the same shape as the punching blade of the mandrel and engages with the punching receiving blade of the die sleeve And
A lower end insertion portion of the mandrel is disposed in the through hole of the annular material, the annular material is pressed against the die sleeve and the inner die by the punch, and a part of the annular material is dies. The annular material is made to flow into the external tooth forming hole to form a gear shape having the external teeth, the mandrel is lowered, and the annular material is formed by the punching blade of the mandrel and the punching receiving blade of the die sleeve. In the gear forming method, the spline groove is punched in the inner peripheral portion .

In the gear forming apparatus according to the first aspect of the present invention, a gear having external teeth on the outer peripheral side portion and spline grooves on the inner peripheral side portion whose thickness is smaller than that of the outer peripheral side portion is secured to ensure the durability of the mold. Ingenuity is being made to mold accurately.
Specifically, the external teeth are formed by cold forging, and the spline grooves are formed by punching. In order to perform punching, a punching blade is formed on the mandrel, and a punching receiving blade is formed on the die sleeve.

In forming the gear, the lower end insertion portion of the mandrel is disposed in the through hole of the annular material, and the annular material is pressed against the die sleeve and the inner die by a punch. At this time, cold forging is performed, the inner peripheral side portion of the annular material is crushed and the thickness is reduced, and the outer peripheral side portion of the annular material flows to the wall surface of the external tooth forming hole of the die, A gear shape having outer teeth on the outer peripheral side portion is formed while the thickness of the inner peripheral side portion is reduced with respect to the side portion. Thereby, the external teeth excellent in dimensional accuracy can be formed with respect to the annular material.
Next, the mandrel is lowered, and the spline groove is punched in the inner peripheral side portion of the annular material by the mandrel punching blade and the die sleeve punching receiving blade. At this time, the mandrel and inner die holding the inner peripheral side portion of the annular material formed into a gear shape are lowered with respect to the punch and die sleeve holding the outer peripheral portion of the annular material formed into a gear shape. Can do. Thereby, spline grooves excellent in dimensional accuracy can be formed on the gear-shaped annular material.

Thus, the spline groove can be formed with a small pressure by performing punching without performing cold forging on the inner peripheral side portion whose thickness is smaller than that of the outer peripheral side portion. Thereby, it is not necessary to apply a large pressing force to molds such as mandrels, punches, and inner dies, and the durability of these molds can be ensured.
Therefore, according to the gear forming apparatus of the first invention, it is possible to form the gear having the external teeth and the spline grooves with high accuracy while suppressing the pressurizing force required for forming, ensuring the durability of the mold. it can.

Also in the gear forming method of the second invention, a gear having external teeth on the outer peripheral side portion and spline grooves on the inner peripheral side portion whose thickness is smaller than that of the outer peripheral side portion is secured to ensure the durability of the mold. Ingenuity is being made to mold accurately.
Specifically, the external teeth are formed by cold forging, and the spline grooves are formed by punching.
Therefore, according to the gear forming method of the second invention, as in the invention of the gear forming apparatus, the pressing force required for forming is kept small, the durability of the mold is ensured, and the external teeth and spline grooves It is possible to accurately form a gear having

Cross-sectional explanatory drawing which shows the whole gear forming apparatus in an Example. Cross-sectional explanatory drawing which expands and shows the principal part of the gear shaping apparatus in an Example. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically illustrating a main part of a gear forming apparatus in an embodiment, and is a cross-sectional explanatory diagram illustrating a state before pressurizing an annular material. FIG. 4 is a cross-sectional explanatory view taken along line AA in FIG. 3 in the embodiment. FIG. 4 is a cross-sectional explanatory view taken along the line B-B in FIG. 3 in the example. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically illustrating a main part of a gear forming apparatus in an embodiment, and is a cross-sectional explanatory diagram illustrating a state in which an inner peripheral side portion of an annular material is pressed by an inner punch. CC sectional view explanatory drawing in FIG. 6 in an Example. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the principal part of the gear shaping apparatus in an Example typically, Comprising: Cross-sectional explanatory drawing which shows the state which pressurized the outer peripheral side part of the annular | circular shaped material with the outer punch. DD sectional view explanatory drawing in FIG. 8 in an Example. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram schematically showing a main part of a gear forming apparatus in an embodiment, and is a cross-sectional explanatory view showing a state in which an inner peripheral side portion of an annular material is punched out by a mandrel. The EE arrow directional cross-sectional explanatory drawing in FIG. 10 in an Example. FIG. 11 is a cross-sectional explanatory view taken along line FF in FIG. 10 in the example. The perspective explanatory drawing which shows the gearwheel shape | molded by the gear shaping apparatus in an Example. FIG. 4 is a diagram illustrating the same state as FIG. 3 in the embodiment, and is a cross-sectional explanatory diagram illustrating a case where the shape of the mandrel is different.

A preferred embodiment of the gear forming apparatus and method of the first invention described above will be described.
In the first invention, the punch includes an inner punch disposed on the outer periphery of the mandrel and an outer punch disposed on the outer periphery of the inner punch, and the annular material is pressurized with the inner punch to form the gear shape. It is preferable that the inner peripheral side portion of the outer peripheral side of the outer peripheral side portion of the gear and the outer teeth be pressed by pressing the die with the outer punch while pressing the annular material.
In this case, the pressing force required for forming the gear can be further reduced by shifting the timing of pressing by the inner punch and the timing of pressing by the outer punch.

Further, it is preferable that the spline groove is punched by lowering the mandrel in a state where the inner peripheral side portion of the gear shape is pressurized by the inner punch.
In this case, the punching process of the spline groove can be performed in a state closer to the hydrostatic pressure, and the processing accuracy of the spline groove can be improved.

Further, the mandrel is formed with a lower end insertion portion having a circular cross-section with a diameter smaller than that of the outer peripheral portion below the outer peripheral portion where the punching blade is formed, and when the annular material is pressed by the punch In the mandrel, the step surface between the outer peripheral portion and the lower end insertion portion is aligned with the lower end surface of the punch, and an annular space is formed on the inner peripheral side of the annular material to form the punch. At the same time, the mandrel is preferably lowered.
In this case, when the annular material is pressurized by the punch, it is easy to cause a part of the annular material to flow into the annular space, and a part of the annular material is applied to the engagement teeth of the punch. It can prevent you from escaping. Therefore, the annular material can be formed into a gear shape with higher accuracy.

Hereinafter, embodiments of the gear forming apparatus and method according to the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, the gear forming apparatus 1 of the present example has outer teeth 821 on the outer peripheral side portion 82 and spline grooves 831 on the inner peripheral side portion 83 whose thickness is smaller than that of the outer peripheral side portion 82. The gear 8 is formed from the annular material 80. The gear forming apparatus 1 includes the following die 3, mandrel 4, punch 5, die sleeve 6, and inner die 7, and performs cold hermetic forging and punching by a one-shot operation of lowering the mandrel 4 and punch 5. The gear 8 is formed by processing.

  As shown in FIGS. 2 and 3, the die 3 is provided with an external tooth forming hole 31 for forming the external tooth 821. The mandrel 4 is provided with a punching blade 411 on the outer peripheral portion 41 for punching the spline groove 831 in the annular material 80 in a state where the lower end insertion portion 42 is disposed in the through hole 81 of the annular material 80. The punch 5 is arranged on the outer periphery of the mandrel 4, has an engagement tooth 511 that engages with the punching blade 411 on the inner peripheral portion, and is configured to pressurize the upper surface of the annular material 80.

  The die sleeve 6 receives a load applied to the annular material 80 from the punch 5, has an engagement tooth 62 that engages with the external tooth forming hole 31 of the die 3, and has an annular shape together with the punching blade 411 of the mandrel 4. A punching receiving blade 61 for punching the spline groove 831 in the material 80 is provided on the inner peripheral portion. The inner die 7 has an insertion hole 72 for inserting the lower end insertion portion 42 of the mandrel 4 in the inner peripheral portion, has the same shape as the punching blade 411 of the mandrel 4, and engages with the punching receiving blade 61 of the die sleeve 6. Engaging teeth 71 are provided.

  As shown in FIG. 3, the gear forming apparatus 1 has the lower end insertion portion 42 of the mandrel 4 disposed in the through hole 81 of the annular material 80, and the annular material 80 with respect to the die sleeve 6 and the inner die 7 by the punch 5. 6 and 8, as shown in FIGS. 6 and 8, a part of the annular material 80 is caused to flow into the external tooth forming hole 31 of the die 3 to form a gear shape having the external teeth 821, and as shown in FIG. The mandrel 4 is lowered, and the spline groove 831 is punched into the inner peripheral portion 83 of the annular material 80 by the punching blade 411 of the mandrel 4 and the punching receiving blade 61 of the die sleeve 6.

Hereinafter, the gear forming apparatus 1 and its method of this example will be described in detail with reference to FIGS.
FIG. 1 is a diagram showing the overall configuration of the gear forming apparatus of this example, and FIG. 2 is an enlarged view showing the main part of the gear forming apparatus. 3 to 12 are diagrams schematically showing a gear forming device for easy understanding of the description.
In the gear forming method of this example, by moving the die and performing cold forging on the annular material 80, the gear shape having the external teeth 821 is formed, and in the state where the gear shape is formed, Further, the spline groove 831 is formed by punching the annular material 80 having a gear shape by moving it.

As shown in FIG. 13, the gear 8 formed by the gear forming apparatus 1 of the present example is integrally connected to the inner peripheral side portion 83 having the spline groove 831 at one axial end with respect to the outer peripheral side portion 82 having the outer teeth 821. It is made. In the gear forming apparatus 1 of this example, the gear 8 in which the inner peripheral portion 83 is formed on the lower end side with respect to the outer peripheral portion 82 is formed. The axial direction of the gear 8 refers to the direction of the central axis. The gear 8 of this example is a sun gear used for an automatic transmission.
The gear 8 may be formed by integrally connecting the inner peripheral side portion 83 to an intermediate portion in the axial direction with respect to the outer peripheral side portion 82. In this case, the shapes of the upper surfaces of the die sleeve 6 and the inner die 7 are changed.

As shown in FIGS. 2 and 3, the punch 5 of this example includes an inner punch 51 disposed on the outer periphery of the mandrel 4 and an outer punch 52 disposed on the outer periphery of the inner punch 51. The inner punch 51 is disposed on the outer periphery of the mandrel 4, and has an engagement tooth 511 that engages with the punching blade 411 on the inner peripheral portion, and pressurizes the upper surface of the inner peripheral side portion 83 of the annular material 80. It is configured. The outer punch 52 is disposed on the outer periphery of the inner punch 51 and abuts around the upper end opening 32 of the external tooth forming hole 31 of the die 3 so that the outer peripheral side portion 82 of the annular material 80 is lowered while the die 3 is lowered. It is comprised so that the upper surface of may be pressurized.
As shown in FIG. 6, the gear forming apparatus 1 pressurizes the annular material 80 by the inner punch 51 to form the gear-shaped inner peripheral portion 83, and lowers the die 3 by the outer punch 52 as shown in FIG. The annular material 80 is pressed while the gear-shaped outer peripheral portion 82 and the external teeth 821 are formed.

As shown in FIGS. 2 and 3, the mandrel 4 of the present example is formed by forming a lower end insertion portion 42 having a circular cross section having a diameter smaller than that of the outer peripheral portion 41 below the outer peripheral portion 41 where the punching blade 411 is formed. . A step surface 43 is formed between the outer peripheral portion 41 and the lower end insertion portion 42.
In addition, the gear forming apparatus 1 of the present example has the mandrel 4 in a state where the inner peripheral portion 83 of the gear shape is pressurized by the inner punch 51 in order to perform the punching process of the spline groove 831 in a state closer to hydrostatic pressure. And the spline groove 831 is punched out.

  Further, as shown in FIGS. 3 and 6, the gear forming apparatus 1 facilitates the flow of a part of the annular material 80 and presses the annular material 80 when the annular material 80 is pressurized by the inner punch 51. In order to prevent the portion from escaping into the groove of the punching blade 411 of the mandrel 4, the step surface 43 of the mandrel 4 and the lower end surface of the inner punch 51 are aligned to form an annular space S on the inner peripheral side of the annular material 80. Thus, the mandrel 4 is moved down together with the inner punch 51.

  In addition, as shown in FIG. 14, the annular material 80 may be pressed by forming the outer peripheral portion 41 of the mandrel 4 to be long downward and setting the stepped surface 43 of the mandrel 4 lower than the lower end surface of the inner punch 51. it can. Between the step surface 43 and the upper surface of the inner die 7, an annular space S having a height substantially equal to the formation height of the inner peripheral portion 83 of the gear 8 can be formed.

As shown in FIG. 3, a plurality of forming teeth 311 arranged in the circumferential direction are formed on the wall surface of the external tooth forming hole 31 of the die 3 of this example. As shown in FIG. 13, the gear 8 formed in the gear forming apparatus 1 of this example is a helical gear (helical gear), and the external teeth 821 of the gear 8 of this example are inclined with respect to the axial direction of the gear 8. The tooth surface is a helical tooth surface.
Around the upper end opening 32 of the external tooth forming hole 31, an arrangement recess 33 is formed in which the lower end 521 of the outer punch 52 is arranged and abuts.

  As shown in FIG. 1, the die 3 is configured to rotate when forming the external teeth 821 and taking out the gear 8 in order to form a helical tooth surface on the external teeth 821 of the gear 8. Specifically, the die 3 is disposed in the die holder 21, and in the die holder 21, a bearing portion 25 that can slide up and down and rotate is provided below the die 3. The bearing portion 25 is biased upward by the air cushion 24, and the die 3 is biased upward by the air cushion 24 and the bearing portion 25.

As shown in FIGS. 1 and 2, the die sleeve 6 is formed in a cylindrical shape, and is disposed so as to be rotatable with respect to the die 3 together with the inner die 7. The die sleeve 6 and the inner die 7 are configured to be raised by the payout pins 23 when the formed gear 8 is taken out from the die 3.
An insertion hole 72 for inserting the lower end insertion portion 42 of the mandrel 4 and positioning it with the mandrel 4 is formed in the center portion of the inner die 7. The inner die 7 is disposed so as to be rotatable with respect to the die 3 together with the die sleeve 6.

  As shown in FIG. 1, the mandrel 4, the inner punch 51, and the outer punch 52 are arranged in a punch holder 22 that moves up and down by receiving power such as hydraulic pressure or electric power. Further, the mandrel 4 and the inner punch 51 are disposed so as to be movable up and down with respect to the punch holder 22 provided with the outer punch 52 by receiving power by hydraulic pressure, electricity, or the like.

Next, a method for forming the gear 8 having the external teeth 821 and the spline grooves 831 using the gear forming apparatus 1 of this example will be described.
In forming the gear 8, as shown in FIG. 3, the die 3, the die sleeve 6, and the inner die 7 are placed in their original positions, and an annular material 80 is formed on the upper surface of the die sleeve 6 in the outer tooth forming hole 31 of the die 3. Is placed. Next, the mandrel 4, the inner punch 51, and the outer punch 52 are lowered simultaneously by lowering the punch holder 22. At this time, the step surface 43 of the mandrel 4 and the lower end surface of the punch 5 are aligned to form an annular space S on the inner peripheral side of the annular material 80, and the mandrel 4, the inner punch 51, and the outer punch 52 are lowered. .

As shown in FIG. 3, the lower end insertion portion 42 of the mandrel 4 is inserted and arranged in the through hole 81 of the annular material 80, the lower end portion 521 of the outer punch 52 abuts on the arrangement recess 33 of the die 3, and the inner punch 51 Is in contact with the upper end surface of the annular material 80.
Here, FIG. 4 shows a cross section taken along line AA in FIG. 3, and FIG. 5 shows a cross section taken along line BB in FIG.

Next, as shown in FIG. 6, the mandrel 4 and the inner punch 51 are lowered with respect to the outer punch 52, and the inner punch 51 presses the annular material 80 against the die sleeve 6 and the inner die 7. At this time, cold forging is performed, the inner peripheral side portion 83 of the annular material 80 is crushed and the thickness is reduced, and this inner peripheral side portion 83 is the inner peripheral side portion 83 of the gear 8 as a molded product. Molded to a thickness of Further, the outer peripheral side portion 82 of the annular material 80 flows toward the outer peripheral side to the wall surface of the external tooth forming hole 31 of the die 3.
Here, in FIG. 7, the CC arrow directional cross section in FIG. 6 is shown.

Next, as shown in FIG. 8, the outer punch 52 is lowered while the die 3 is pressed down against the mandrel 4 and the inner punch 51. At this time, the die 3 is pushed down while rotating against the urging force of the air cushion 24 along the spiral of the helical tooth surface (molded tooth) 311 of the external tooth molding hole 31.
Thereby, the outer peripheral side portion 82 of the annular material 80 is pressurized by the outer punch 52, and the outer peripheral side portion 82 of the annular material 80 flows over the entire wall surface of the external tooth forming hole 31 of the die 3.

Further, when the outer punch 52 pressurizes the outer peripheral side portion 82 of the annular material 80, the pressing force of the inner punch 51 (the force with which the inner punch 51 presses the annular material 80) is made zero. Thereby, a part of the annular material 80 can flow more easily on the wall surface of the external tooth forming hole 31.
In this way, the thickness of the inner peripheral side portion 83 is reduced with respect to the outer peripheral side portion 82, and a gear shape having the outer teeth 821 is formed on the outer peripheral side portion 82. 821 can be formed.
Here, in FIG. 9, the DD arrow directional cross section in FIG. 8 is shown.

Next, as shown in FIG. 10, the mandrel 4 is lowered, and the spline groove 831 is punched into the inner peripheral portion 83 of the annular material 80 by the punching blade 411 of the mandrel 4 and the punching receiving blade 61 of the die sleeve 6. At this time, the mandrel which clamps the inner peripheral side portion 83 of the annular material 80 formed into a gear shape with respect to the inner punch 51 and the die sleeve 6 which sandwiches the outer peripheral portion 82 of the annular material 80 formed into a gear shape. 4 and the inner die 7 are lowered. Further, an upward pressing force is applied to the inner die 7, and these are lowered while the inner peripheral side portion 83 of the annular material 80 is sandwiched between the mandrel 4 and the inner die 7. it can. Thereby, the spline groove 831 excellent in dimensional accuracy can be formed in the gear-shaped annular material 80.
Here, FIG. 11 shows a cross section taken along line EE in FIG. 10, and FIG. 12 shows a cross section taken along line FF in FIG.

When the mandrel 4 is lowered, the gear-shaped inner peripheral portion 83 is pressurized by the inner punch 51. Thereby, the punching process of the spline groove 831 can be performed in a state closer to the hydrostatic pressure, and the processing accuracy of the spline groove 831 can be improved.
A gear 8 having a helical outer tooth 821 on the outer periphery and a spline groove 831 on the inner periphery is formed, and an inner peripheral side end of the annular material 80 is used as a scrap 84 on the inner die 7. Placed on.
Thereafter, the mandrel 4, the inner punch 51, and the outer punch 52 are raised by raising the punch holder 22. Next, the die sleeve 6 and the inner die 7 are raised while the die 3 is rotated, and the formed gear 8 is taken out and the scrap 84 is taken out.

Thus, the spline groove 831 can be formed with a small pressure by performing the punching process on the inner peripheral side portion 83 whose thickness is smaller than that of the outer peripheral side portion 82 without performing cold forging. Therefore, it is not necessary to apply a large pressure to the molds such as the mandrel 4, the inner punch 51, and the inner die 7, and the durability of these molds can be ensured.
Therefore, according to the gear forming apparatus 1 and the method of this example, the pressing force required for forming is suppressed to be small, the durability of the mold is ensured, and the gear 8 having the external teeth 821 and the spline grooves 831 can be accurately obtained. Can be molded.

DESCRIPTION OF SYMBOLS 1 Gear forming apparatus 21 Die holder 22 Punch holder 3 Dies 31 External tooth forming hole 32 Upper end opening part 4 Mandrel 41 Outer peripheral part 411 Punching blade 42 Lower end insertion part 43 Step surface 5 Punch 51 Inner punch 511 Engagement tooth 52 Outer punch 521 Lower end part 6 Die sleeve 61 Punching receiving blade 62 Engagement tooth 7 Inner die 71 Engagement tooth 72 Insertion hole 8 Gear 80 Toroidal material 81 Through hole 82 Outer peripheral part 821 External tooth 83 Inner peripheral part 831 Spline groove

Claims (5)

An apparatus for forming a gear having an external tooth on the outer peripheral side portion and a spline groove on the inner peripheral side portion whose thickness is smaller than that of the outer peripheral side portion from an annular material,
A die provided with an external tooth forming hole for forming the external tooth;
In a state where the lower end insertion portion is arranged in the through hole of the annular material, a mandrel provided with a punching blade for punching the spline groove in the annular material,
A punch that is disposed on the outer periphery of the mandrel, has an engagement tooth that engages the punching blade on the inner periphery, and pressurizes the upper surface of the annular material;
The spline groove is formed in the annular material together with the punching blade of the mandrel and has an engaging tooth that receives a load applied to the annular material from the punch and engages with the external tooth forming hole of the die. A die sleeve having a punching receiving blade for punching in the inner periphery,
An inner die having an insertion hole for inserting a lower end insertion portion of the mandrel in an inner peripheral portion, and having an engagement tooth that has the same shape as the punching blade of the mandrel and engages with the punching receiving blade of the die sleeve And
A lower end insertion portion of the mandrel is disposed in the through hole of the annular material, the annular material is pressed against the die sleeve and the inner die by the punch, and a part of the annular material is dies. The annular material is made to flow into the external tooth forming hole to form a gear shape having the external teeth, the mandrel is lowered, and the annular material is formed by the punching blade of the mandrel and the punching receiving blade of the die sleeve. A gear forming apparatus, wherein the spline groove is punched in an inner peripheral side portion. The gear forming apparatus according to claim 1, wherein the punch includes an inner punch disposed on an outer periphery of the mandrel and an outer punch disposed on an outer periphery of the inner punch.
The annular material is pressed by the inner punch to form the inner peripheral portion of the gear shape, and the annular material is pressed while the die is pressed by the outer punch to press the outer peripheral portion of the gear shape and the gear. A gear forming apparatus for forming external teeth.   3. The gear forming apparatus according to claim 2, wherein the mandrel is lowered to punch the spline groove in a state where the inner peripheral side portion of the gear shape is pressurized by the inner punch. apparatus. The gear forming apparatus according to any one of claims 1 to 3, wherein the mandrel includes a lower end insertion portion having a circular cross-sectional shape having a diameter smaller than that of the outer peripheral portion, below the outer peripheral portion where the punching blade is formed. Formed,
When pressurizing the annular material with the punch, the step surface between the outer peripheral portion and the lower end insertion portion of the mandrel is aligned with the lower end surface of the punch, and the inner peripheral side of the annular material An annular space is formed in the mandrel and the mandrel is lowered together with the punch. A method of forming a gear having spline grooves on an inner peripheral side portion having outer teeth on the outer peripheral side portion and having a thickness smaller than the outer peripheral side portion from an annular material,
A die provided with an external tooth forming hole for forming the external tooth;
In a state where the lower end insertion portion is arranged in the through hole of the annular material, a mandrel provided with a punching blade for punching the spline groove in the annular material,
A punch that is disposed on the outer periphery of the mandrel, has an engagement tooth that engages the punching blade on the inner periphery, and pressurizes the upper surface of the annular material;
The spline groove is formed in the annular material together with the punching blade of the mandrel and has an engaging tooth that receives a load applied to the annular material from the punch and engages with the external tooth forming hole of the die. A die sleeve having a punching receiving blade for punching in the inner periphery,
An inner die having an insertion hole for inserting a lower end insertion portion of the mandrel in an inner peripheral portion, and having an engagement tooth that has the same shape as the punching blade of the mandrel and engages with the punching receiving blade of the die sleeve And
A lower end insertion portion of the mandrel is disposed in the through hole of the annular material, the annular material is pressed against the die sleeve and the inner die by the punch, and a part of the annular material is dies. The annular material is made to flow into the external tooth forming hole to form a gear shape having the external teeth, the mandrel is lowered, and the annular material is formed by the punching blade of the mandrel and the punching receiving blade of the die sleeve. A gear forming method, wherein the spline groove is punched in an inner peripheral side portion .

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