JPS62261752A - Method for molding bottomed internal tooth profile - Google Patents

Abstract

PURPOSE:To prevent a thick walled part from being formed in a product and improve a working property by bringing the tapered faces of both the inner peripheries of the annular projection of a molding punch and the clearance groove of a cup-like stock into contact with each other in a method of molding a bottomed internal tooth profile. CONSTITUTION:A stock 7 is set in a die 3 having a throttle part 3a in its inner periphery. The stock 7 is held in between a molding punch 5 having a tooth profile 5a on its outer peripheral face from the bottom part and a pushing punch 6 and, as it is pushed down, an internal tooth profile following the shape of the tooth profile 5a can be obtained. An annular projection 9 is provided on the peripheral edge part of the end face of the molding punch 5, a clearance groove 10 is previously formed on the hole bottom of the stock 7, the inner peripheral face of each of the projection 9 and the groove 10 is formed into a tapered shape, and the tapered faces 9a, 10a are brought into contact with each other. That is, by taperedly fitting the projection 9 and the clearance groove 10, the centering between the stock 7 and the molding punch 5 can be easily and directly carried out, enabling a highly accurate internal tooth profile without a thick walled part to be molded while also improving a working property.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an internal tooth profile with a bottom, in which an internal tooth profile such as a tin line is formed on the inner circumferential surface of a cup-shaped rope material by drawing. Concerning a molding method.

(Prior art) Conventionally, a forming punch with a gear on the outer periphery is inserted into a cup-shaped material, the material is squeezed by a die on the outer periphery, and an internal tooth profile is formed on the inner circumferential surface of the material after the tooth profile of the forming punch. In this case, there are two methods: backward extrusion, in which the material is drawn and formed from the bottom side, and forward extrusion, in which the material is drawn and formed from the open end side.

The applicant of the present application previously disclosed in Japanese Patent Application No. 109338 that as a forward extrusion method, a cup-shaped cable member is inserted into a die a with its open end facing F, as shown in FIG. With the forming punch C in a inserted into the blank, press down the blank with the upper pusher A d, while pushing the blank downward at the drawing part e on the inner periphery of the die a. Squeeze to form an internal tooth profile that follows the tooth profile f on the outer periphery of the molding nozzle C.

Furthermore, an annular protrusion g is provided on the outside of the end face of the forming punch C, and a relief groove for receiving the protrusion g is formed in advance at the bottom corner of the rope material.

We have proposed a method that allows the internal tooth profile to be accurately formed as close to the bottom of the hole as possible.

(Problem to be solved by the invention) By the way, in the above case, the material is molded at 9 inches C.
K is supported by an annular protrusion g in contact with the bottom of the relief groove, or as shown in FIG. Generally, the end faces of the blank are supported by abutting against each other, and since there is an insertion clearance between the outer periphery and the inner periphery of the blank with respect to the die a and the forming arm cK, the play in the radial direction of the blank is supported. This may cause the material to be flanged between the notching punch C and the push punch d in an eccentric state with respect to the forming punch C and forming a pattern, resulting in uneven thickness.

In this case, it is possible to prevent uneven thickness by narrowing the clearance, but this will make it difficult to set the material, and if it is inserted forcibly, the material will fall over, promoting uneven thickness. Then it becomes undesirable.

Note that even when backward extrusion is performed, uneven thickness may occur due to eccentricity of the material.

SUMMARY OF THE INVENTION An object of the present invention is to provide a molding method that solves the above-mentioned problems by preventing eccentricity of the material by utilizing the escape groove of the material and the annular protrusion of the forming punch.

(Means for Solving the Problems) In order to achieve the above object, the present invention inserts a forming punch having a tooth profile on the outer periphery into a cup-shaped material, and inserts the material into a cup-shaped material through a die 6a on the outer periphery so that the inner periphery of the material is A method of forming an internal tooth profile on a surface that follows the tooth profile of the forming punch, wherein an annular protrusion is provided on the peripheral edge of the end face of the forming punch, and a recess for receiving the protrusion is provided at the corner of the hole bottom of the material. In the case where a groove is formed in advance, the tapered surface of the inner periphery of the core annular projection is brought into contact with the tapered surface of the inner periphery of the relief groove to center and support the material with respect to the forming notch. It is characterized by the following.

(Function) Due to the contact between the nine surfaces of the escape groove and the annular protrusion, the material is securely centered and supported by the molded nozzle.

Even if the insertion clearance between the outer periphery and the inner periphery of the material is large, 2, uneven thickness due to eccentricity of the material does not occur, the workability of setting the material is improved, and a highly accurate product can be obtained.

(Example) Figure 1 shows a drawing forming device, and a die holder (79 on υ)
(2) Place the die (3) having the bushing part (3a) of the K inner station, and place it on the movable plate (4) supported on the holder (υ via the urethane spring (4a)). A 5-inch molding/R punch having a tooth profile (5a) on the upper outer circumferential surface is erected, and this is inserted into the die (3) with a gap,
Furthermore, a push punch (
6), insert and set the cup-shaped material (η with its open end facing downwards) into the die (3) as shown in Figure 2a,
# Move the core pressing nozzle (6) downward with the forming punch (6) inserted into the material (7).

The material (7) is punched with both punches (5) (
6) Press down while holding the bottom part of the material, push the material (7) downward through the embossed part (3a) and squeeze it inwardly, forward as shown in Figure 2C. We decided to perform drawing molding by extrusion.

According to this, a product W having an internal tooth profile Wa of a nine-sided curve following the tooth profile (5a) of the forming punch (5) is obtained, and then inserted into the punch (6) as shown in FIG. 2d. The product W is released from the mold by moving the knockout (8 mm) up.

Here, the forming punch (5) is provided with an annular projection (9) on the peripheral edge of its end surface, and an escape groove OQ for receiving the projection (9) is preliminarily formed at the bottom corner of the hole of the material (7). With the protrusion (9) inserted into the relief @aO, drawing and forming is performed as described above to form a hole as close to the bottom of the hole as possible.
tK Wataru is internal tooth Ft! This made it possible to effectively form Ha.

By the way, the die (3) and forming punch (5) of the material (7)
), there is an insertion clearance between the outer periphery and the inner periphery of the material (7) as shown in Figure 3, and if this continues, play in the radial direction of # material (7) will occur. However, in the present invention, the tapered surface (9aJ) on the inner circumference of the annular projection (9) is brought into contact with the tapered surface (10aJ) on the inner circumference of the relief #lOO. That is, the protrusion (9) is tapered fitted into the relief #IO□, so that the material (7) is centered and supported with respect to the forming punch (6).

According to this, even if the insertion clearance is sufficiently large, the centering accuracy of the material (7) and the forming punch (5) is not guaranteed, and the material (7) and the forming punch (5) are not aligned from the start to the end of forming.
) are directly centered to form a highly accurate internal tooth profile Wa with no thickness deviation.

The embodiments in which the present invention is applied to edge forming by forward extrusion have been described above.
The present invention can be similarly applied to the case of molding.

(Effects of the Invention) As described above, according to the present invention, it is possible to improve the workability of setting the material and obtain a highly accurate product without uneven thickness, and the means for flattening increases the effective area of the internal tooth profile. By utilizing the annular protrusion of the forming punch and the relief groove of the material, and simply taperingly fitting the protrusion into the relief groove, there is an effect that is advantageous both in terms of construction and cost.

[Brief explanation of drawings]

Fig. 1 is a cutaway sectional view of the drawing forming device used to carry out the method of the present invention, Fig. 2 a to d are explanatory views of its operation, and Fig. 3 is an enlarged sectional view showing the relationship between the material and the forming punch. FIGS. 4 and 5 are cutaway views corresponding to FIG. 3 of Hikari's proposal. (3)...Die (season...Forming punch (5)...Tooth profile of forming punch (7)...Material (9)
)...Annular projection OQ...Escape groove C9a)
(10a)...Tapered surface W...Product Wa...
2 people outside the internal tooth profile

Claims (1)

[Claims] A method of inserting a forming punch having a tooth profile on the outer periphery into a cup-shaped material, and squeezing the material with a die on the outer periphery to form an internal tooth profile that follows the tooth profile of the forming punch on its inner peripheral surface, the method comprising: A forming punch is provided with an annular protrusion on the peripheral edge of the end face, and a relief groove is formed in advance at the bottom corner of the hole to receive the protrusion, and the relief groove is provided on the tapered surface of the inner periphery of the annular protrusion. A method for forming an internal tooth profile with a bottom, characterized in that the material is centered and supported with respect to the forming punch by bringing the tapered surface of the inner periphery into contact with the forming punch.