JPH07108341A - Method for forming cylindrical gear by forging and heading - Google Patents

Abstract

PURPOSE:To form a cylindrical gear with high precision by forging and heading. CONSTITUTION:This method is a method for forming a cylindrical gear with a tooth surface 51 formed on its outer peripheral surface by forging and heading with a transfer press on which plural dies are arranged in positions adjacent to each other. A cylindrical blank 2 with a partition, is formed by driving a first standby pin 83 and a second punch 82 standing by in a die, in both ends of a solid blank. In a following process, a sleeve-shape blank 3 is formed by punching the partition 21 of the cylindrical blank 2 with the partition. In a following process, the sleeve-shape blank 3 is driven into a die cavity with the tooth surface formed on its inner peripheral surface. A blank 4 with teeth, having a flange 41 with an excess material projected in the center part of its inner surface, having a tooth surface 51 on its outer periphery, which is lower than the height of the sleeve-shape blank 3. In a following process, the flange 41 of the blank 4 with teeth, is punched to form a cylindrical gear.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forging and forging a solid blank cylindrical gear.

[0002]

2. Description of the Related Art Conventionally, a gear is forged and press-formed by a transfer press in which a plurality of dies are arranged adjacent to each other.

This is a cylindrical blank according to the first step.
A first punch (81) is driven into (not shown) to form the flat solid blank (7) of FIG.

In the second step shown in FIG. 9, a second punch (82) and a first standby pin (83) are driven on both sides of the blank to form a cylindrical blank (71) with a partition (70).

In the third step, a mold cavity having a tooth surface formed on the inner peripheral surface
The cylindrical blank with partition wall (71) is driven into (not shown), and as shown in FIG. 10, the height is lower than that of the cylindrical blank with partition wall, and the tooth surface (73) is provided on the outer periphery, and the inner surface is A toothed blank (72) having a thin partition wall (74) in the center is formed.

In the fourth step shown in FIG. 11, the partition wall (75) of the toothed blank (72) is punched to forge and forge a gear.

[0007]

In the forging / pressing method described above, in the third step of FIG. 10, when the tooth surface is formed, the material is eroded into the tooth surface of the inner surface of the mold, so that the partition wall shown in FIG. The blank 71 is pressed to reduce the height of the blank and the partition wall is pressed from both sides by the third punch 85 and the second standby pin 86.

The partition wall (70) formed in the second step shown in FIG.
Has increased hardness due to work hardening. In the next step, the partition wall (70) having a high hardness is further pressed to reduce the wall pressure, so that the third punch (85) and the second standby pin (86 ), A large resistance acts, and the blank (71) with the partition wall cannot be driven straight into the axial center of the blank (71), resulting in misalignment.

Since the grade of the gear is determined on the basis of the inner diameter, the misalignment directly affects the grade of the gear and it is not possible to form a gear of high grade. Further, since the pressure resistance at the time of shifting from the second step to the third step is large, it is not possible to form a gear having a thin wall thickness, and the ratio of the inner diameter to the outer shape is limited. The present invention clarifies a method for forming a cylindrical gear having a high grade and a small wall thickness by forging and forging.

[0010]

According to the method for forging and forging a cylindrical gear of the present invention, a cylindrical gear (5) having a tooth surface (51) formed on an outer peripheral surface thereof is provided.
Is a method of forging and forging with a transfer press in which a plurality of dies are arranged adjacent to each other.
Cylindrical blank with partition walls by driving the first standby pin (83) and the second punch (82) that are in standby in the die at both ends of (1).
Form (2).

In the next step, the partition wall (21) of the partition-equipped cylindrical blank (2) is punched out to form a sleeve-shaped blank (3), and in the next step, a mold cavity having a tooth surface on the inner peripheral surface is formed. Driving the sleeve blank (3), the sleeve blank (3)
A toothed blank (4) is formed which has a lower height than the above and has a tooth surface (51) on the outer circumference and a flange (41) formed by overhanging an extra material in the center of the inner surface.

In the next step, the flange (41) of the toothed blank (4) is punched out to form a cylindrical gear (5).

[0013]

[Operation and effect] A sleeve blank (3) is once formed from a solid blank, and the sleeve blank (3) is driven into a die to form a tooth surface on the outer periphery, which causes work hardening as in the conventional case. It is possible to prevent misalignment of the third punch (85) and the second standby pin (86) due to further thinning of the partition wall, which makes it possible to manufacture high-quality gears, and also the sleeve-shaped blank (3). Since the tooth surface is formed in the gear, it is possible to manufacture a gear having a thin wall thickness.

[0014]

EXAMPLE FIG. 1 shows a cylindrical blank (10) obtained by shearing a wire rod to a predetermined size, and FIGS.
The step of forming by pressing to form the cylindrical gear (5) is shown. The cylindrical gear (5) has a tooth surface (51) formed on the outer circumference of a sleeve whose height is smaller than the outer diameter.

Each step is carried out in a die (not shown) fixedly arranged in a horizontal row at equal intervals on a die block (not shown) of a horizontal transfer press called a parts homer.

1 to 6, the lower part is the die side and the upper part is the punch side. In the first step, as shown in FIG. 2, the cylindrical blank (10) of FIG. 1 is driven into the die by the first punch (81) to form the flat body blank (1), and the flat body blank (1) is formed. Tapered surface on the outer periphery of the die back side
(12) is formed, and a circular recess (21) is formed on the end face on the punch side.

By the second step shown in FIG. 3, the flat punch (1) is turned over by 180 ° and the second punch (82) is turned on.
The second blank (82) and the first standby pin (83) waiting in the die are bited into both sides of the blank, by which the cylindrical blank (2) with the partition wall (21) is driven. Form.

According to the third step shown in FIG. 4, the partition wall (21) of the cylindrical blank (2) with the partition wall is punched out by the first hole punching pin (84) in the next die, and the sleeve blank (3).
To form.

In the fourth step shown in FIG. 5, the sleeve blank (3) is driven into the next die by the third punch (85), and the second punch pin which waits in the third punch (85) and the die. Both end surfaces of the sleeve-like blank (3) are pressed by the (86), the sleeve-like blank (3) is projected outward, and the material is bite into the tooth surface groove formed on the inner surface of the die cavity of the die.

Excess material is extruded between the third punch (85) and the second standby pin (86) to form the flange (41).

By the fifth step shown in FIG. 6, with respect to the toothed blank (4), the second punching pin (8) is formed in the next die.
The flange (41) is punched by hitting 7) to form the tubular gear (5).

As described above, the sleeve blank (3) is once formed from the solid blank, and the sleeve blank (3) is formed.
The core of the third punch (85) and the second standby pin (86) is caused by further thinning the partition wall that has undergone work hardening as in the past, because the tooth surface is formed on the outer periphery by punching into the die. Misalignment can be prevented and high-quality gears can be manufactured. In addition, since the tooth surface is formed on the sleeve-shaped blank (3), it is possible to manufacture a thin gear.

FIG. 7 shows a fourth example of manufacturing a helical gear.
The die of the process is shown. The first to third steps and the sixth step are the same as above. In FIG. 7, a helical tooth surface (91) is formed on the inner peripheral surface of the mold cavity (9), and the bottom of the mold cavity (9) has a fixed inner pin (94) and the inner pin (94). The outer pins (95) slidably fitted on the pins (94) are formed by the respective tip surfaces.

The outer pin (95) is biased in the retracting direction by a spring (97), and a groove (98) having the same lead angle as the lead angle of the helical tooth surface (91) is formed on the outer peripheral surface. A guide pin (99) is fitted in the groove (98).

The inner punch (93), the outer punch (92) slidably fitted in the inner punch (93) and the inner pin (94)
The sleeve blank (3) is shaped into a toothed blank (4).

Next, while the outer punch (92) and the inner punch (93) are being retracted, the kick pin (96) kicks the toothed blank (4) through the outer pin (95) into the die. At this time, the outer pin (95) is guided by the guide pin (99) to push out the toothed blank (4) while rotating at the same lead angle as the toothed blank of the toothed blank (4). The blank (4) can be smoothly discharged out of the die.

The present invention is not limited to the configuration of the above embodiment, and various modifications can be made within the scope of the claims.

[Brief description of drawings]

FIG. 1 is a front view of a cylindrical blank.

FIG. 2 is a front view of a flat body blank.

FIG. 3 is a front view of a tubular blank with a partition.

FIG. 4 is a front view of a sleeve-shaped blank.

FIG. 5 is a front view of a toothed blank.

FIG. 6 is a front view of a cylindrical gear.

FIG. 7 is a cross section of a helical gear die.

FIG. 8 is a sectional view of a conventional flat solid blank.

FIG. 9 is a cross-sectional view of a conventional blank with a partition wall.

FIG. 10 is a cross-sectional view of a conventional toothed blank.

FIG. 11 is a sectional view of a conventional gear.

[Explanation of symbols]

 (1) Flat blank (2) Cylindrical blank with partition wall (3) Sleeve blank (4) Toothed blank (5) Cylindrical gear

Claims (1)

[Claims] 1. A cylindrical gear having a tooth surface (51) formed on an outer peripheral surface thereof.
A method of forging and forging (5) with a transfer press in which a plurality of dies are arranged adjacent to each other, and a first standby pin (83) waiting in the die at both ends of the solid blank (1).
Cylindrical blank with partition wall by punching in and second punch (82)
(2) is formed, and in the next step, the cylindrical blank with partition walls (2)
The partition wall (21) is punched out to form a sleeve-shaped blank (3), and in the next step, the sleeve-shaped blank (3) is driven into the mold cavity having the tooth surface formed on the inner peripheral surface, and the sleeve-shaped blank (3) is formed.
A toothed blank (4) having a lower height than the toothed surface (51) on the outer periphery and a flange (41) formed by protruding an extra material at the center of the inner surface is formed, and in the next step, the toothed blank (4) is formed. Blank with
A method of forging and forging a tubular gear by punching out the flange (41) of (4).