KR20120032147A - Yoke manufacturing method - Google Patents

Abstract

PURPOSE: A yoke forming method is provided to implement a continuous forming process with a single forming device, thereby improving productivity. CONSTITUTION: A yoke forming method comprises the steps of: cutting a round rod shaped material, placing the cut material in a first dies, pressing the material with a first punch in order to obtain a first product(10C) with facing webs on one end thereof, placing the first product in a second dies, pressing the first product with a second punch in order to form a second product with flanges horizontal to the webs, placing the second product in a third dies, and pressing the second product with a third punch in order to form a third product in a yoke shape.

Description

YOKE MANUFACTURING METHOD}

The present invention relates to a molding method of the yoke, and in particular, the manufacturing process of the yoke employed in the steering shaft of an automobile is performed by one molding machine, and the processing error can be reduced, thereby improving product reliability. It relates to a molding method of a yoke.

In general, the yoke uses the power of the main shaft when the driven shaft is not in the same line and is inclined at a predetermined angle or collinearly with respect to a main shaft that is rotated, such as a steering shaft of a vehicle or a propulsion shaft that transmits power of the engine. Mainly used for smooth transmission to the driven shaft.

Typically, the yoke is composed of a boss and a pair of webs that face each other on one side of the boss.

In addition, the existing yoke is mainly produced by the casting molding method, in which case it has a disadvantage in that it is easily damaged even in a relatively small impact due to its weak corrosion resistance, as well as corrosion.

Therefore, in order to increase durability, the yoke price is increased because the surface of the yoke must be plated with nickel to prevent corrosion by changing the crystal structure of the metal such as quenching, tempering or soaking to increase strength or hardness. In addition, there are many processing processes according to yoke production and yoke production takes a long time, and therefore, the price of the product is high and thus the competitiveness is lowered.

To this end, a yoke is manufactured by inserting a cylindrical yoke raw material into a yoke die and applying a punch.

That is, the yoke shape of the cylindrical yoke raw material is prepared, the yoke raw material is cut to a length corresponding to the yoke shape, firstly subjected to a primary punching force by applying a punching force, and then the yoke shape to be molded into the primary processed molding. After accommodating the die, the yoke is molded by applying a punching force a plurality of times.

At this time, since the punch is operated and the molding and the die are stopped, the punch is formed by applying a punching force from the upper end of the web, which is the opposite part of the boss, so that the height of the upper end of the web is different from each other.

Accordingly, after yoke molding, a trimming process for equalizing the height of the upper end of the web is required separately.

Therefore, the conventional yoke is subjected to a trimming process separately using a trimming molding machine, so that a continuous production process is impossible, and thus there is a problem in that manufacturing time and cost are increased.

In addition, when the upper edge portion of the web surface, which is a reference surface during post-processing, is angularly formed, it cannot be erected on the bottom surface, and there is a concern that product reliability may be deteriorated when processing errors in both widths of the web occur.

It is an object of the present invention to provide a yoke manufacturing method in which the molding process is improved so that a continuous process of the yoke is performed with one molding machine without requiring a separate trimming process.

In addition, another object of the present invention is to provide a manufacturing method of the yoke which can reduce the processing error during production of the product, and improved the molding process to improve the functionality of the finished product.

The present invention for achieving the above object is to cut the raw material in the form of a round bar, the first molded article having a web facing each other on both sides at one side by receiving the cut molding material in the first dice and applying a pressing force of the first punch A first molding step of molding to have a molding;

After receiving the primary molded primary molded product in the second dice, the punching force of the second punch is applied to one end of the primary molded product so that the heights of both web portions of the primary molded product are the same. A second molding step of forming into a secondary molding each flange portion formed in a horizontal direction:

And after receiving the secondary molded product in a third die, applying a punching force of a third punch to the flange portion of the secondary molded product to cut the third molded product to form a yoke-shaped tertiary molded product. It is done.

The method may further include a preforming step of molding the cut molding material into a preform before forming the cut molding material into a primary molding.

The preliminary forming step may include: a first preliminary forming step of applying a punching force to the cut molding material to form a first preliminary molded article having a convex portion having a convex shape in a lateral direction corresponding to a web portion;

After the first preform is rotated 180 °, a second preliminary molding step of forming a second preform formed by applying a punching force to distinguish the convex portion and the boss portion.

The second preliminary molding step further includes a step of roundly forming corner portions of the convex portions.

The present invention relates to a molding method of the yoke that can be continuously processed to a single molding machine without going through a separate trimming molding machine and to reduce the error of the trimming part. Since the continuous molding process is made, the productivity of the yoke product is greatly improved, which has a useful effect.

In addition, it is possible to secure the uprights of both web portions serving as reference planes during post-processing, and to reduce machining errors of both web portions, thereby improving product reliability.

1 is a schematic view showing a method of forming a yoke according to the present invention.
2 is a view showing a yoke raw material of the present invention.
Figures 3a, 3b, 3c is a view showing the preform after the first preforming step of the present invention in plan, front and side views, respectively.
Figures 4a, 4b, 4c is a view showing the preform after the second preforming step of the present invention in plan, front and side views, respectively.
Figures 5a, 5b, 5c is a planar, front, side views respectively showing the primary molding after the first molding step of the present invention.
Figure 6a, 6b, 6c is a planar, front, side views respectively showing the secondary molding after the second molding step of the present invention.
Figures 7a, 7b, 7c are respectively shown in plan, front and side views of the tertiary molding after the third molding step of the present invention.
8 is a view showing an example of a punch and a die applied to the present invention.
9 is a configuration diagram sequentially showing the second, third molding step of the yoke of the present invention.
10 is a perspective view showing another example of the yoke of the present invention.
Fig. 11 is a flow chart sequentially showing the molding method of the yoke of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Here, the molding machine uses a former as an example.

When the yoke forming method according to the present invention is described with reference to Figs. 1 to 11, the method is formed into a yoke form by applying a plurality of punching forces to the preform formed through the preforming step and the preforming step. It is roughly divided into 1, 2, 3 molding steps.

The preforming step cuts the raw material in the form of a round rod into the appropriate length corresponding to the yoke forming.

The preforming step means preforming the cut material (Y) using a preformed punch and die to preform the round bar shaped molding material before the first molding step.

In the preforming step, a punching force is applied to the cut molding material Y by using a first preliminary forming punch and a first preliminary forming die to have a convex portion 12a having a convex shape in the left and right directions of the boss 11. A first preliminary molding step of forming into a preliminary molded product 10A; After the first preform 10A is rotated 180 °, the second preform is formed so as to separate the convex portion 12b from the boss 11 by applying a punching force using the second preform punch and the second preform die. And a second preliminary molding step of forming the preform 10B.

The reason for rotating the first preform 10A by 180 ° is that when the punching force is applied while the first preform 10A is accommodated in the preform die, the corner portion of the convex portion 12a formed in the first preform molding step is rounded. This is because it is forged.

This allows the surface portions of both webs to be formed flat after being molded into the finished yoke, which makes it possible to stand upright when standing on the floor.

In other words, when the web edge portion is formed to be angular, it is impossible to stand upright, while the yoke finished product of the present invention can stand upright when seated with the bottom surface.

In the second preliminary molding step, as the second preliminary molding is performed by applying a punching force, the second preliminary molding step reduces a machining error of the convex portion 12b corresponding to the web portion, thereby improving product reliability.

The first and second preliminary molding steps may be optionally omitted in the yoke forming method of the present invention.

That is, although the first and second preliminary molding steps may be manufactured without the first and second preliminary molding steps, the first and second preliminary molding steps may be performed through the first and second preliminary molding steps. Not only can this reduce the load on the molding machine, but it can also improve product reliability.

The first molding step includes a primary molding having a web 12c facing each other on one side of the boss 11 by receiving the cut molding material or preformed preform in the first dice and applying a pressing force of the first punch ( Molding to have 10C).

At this time, the primary molded product 10C may have different heights of portions of both webs 12c.

Subsequently, in the second molding step, after receiving the primary molded product 10C in the second die, the secondary molded product 10C is subjected to the punching force of the second punch so that both webs 12d have the same height. It is shape | molded by the secondary molding 10D in which each flange part F was formed in the horizontal direction of 12d.

At this time, in the second molding step, the outer peripheral surfaces of both webs 12d of the primary molded product 10C according to the shape of the second die protrude in the horizontal direction by the pressure at the time of punching, and the width of the protruding flange portion F Is proportional to the web height of the primary molding 10C.

That is, when the right web portion is higher than the left web portion in the secondary forming step, the flange portion of the right web is formed wider than the flange portion of the left web.

Thereafter, the third molding step is to accommodate the secondary molding 10D in the third die, and then apply punching force of the third punch to both flange portions F of the secondary molding 10D to trim the shearing method. It is cut and molded into a yoke-shaped tertiary molding 10E having both webs 12e without flanges.

Accordingly, after the flange part F is separated from the third dice and dropped, the flange part F undergoes a separate disposal process.

Here, since the first, second, and third punches and the first, second, and third dies may vary according to the shape of the yoke, only one example will be described. The punch is referred to by reference numeral 20, and the die is 30 ".

That is, the web of the yoke may have a form protruding outwardly.

Each die has a hole-shaped core in which moldings are inserted and received.

The former molding machine of the present invention is produced by cold forging in yoke production.

The former forming machine is composed of punches and dice required during the first and second preliminary forming steps and the first and second preliminary forming steps, respectively, and the moldings are sequentially formed by clamping mechanisms (not shown) disposed around each die. As it is transported, it goes through a continuous molding process.

The yoke manufactured through the above-described process has a form composed of a boss 11 and a web 12e having a shape facing each other at both ends of one end of the boss 11.

The yoke of the present invention is employed in an automobile steering shaft, and the boss 11 portion of the yoke may have another form, such as being integrally welded to the shaft, or forming a hole 11a for engagement with the shaft.

Briefly summarized yoke molding method of the present invention, after cutting the yoke raw material supplied in the form of a round bar into a molding material (S1), and after molding the preform of the basic form in the first preliminary molding step (S2), (2) forming the convex part of the preform uniformly in the preliminary molding step and smoothly rounding the convex edge part (S3), forming both web parts in the first molding step (S4), and forming the second part After molding the heights of both web portions equally using the flanges in the step (S5), the step of cutting the flanges in a shearing manner in the third molding step (S6).

In the second preliminary forming step, the first preform 10A is rotated 180 °, and the punching force is applied while the convex portion is inserted into the core of the second preliminary molding die, thereby causing an error of the convex portion 12b. In addition, the angled edges of the convex portion can be molded into a smooth round shape.

Therefore, the present invention is a process for forming a convex portion corresponding to the surface of the web portion of the yoke during the continuous process, as well as the productivity is greatly improved because the continuous process is made with one former molding machine compared to the conventional yoke forming method. This makes it possible to stand upright and reduce machining errors to improve product reliability.

Description of the Related Art [0002]
Y: York molding material 10A: First preform
10B: Second Preform 10C: Primary Preform
10D: Secondary molding 10E: Third molding
11: boss 12a: convex (first preform)
12b: convex portion (second preform) 12c: web (primary form)
12d: web (secondary molding) web 12e: web (secondary molding) web
20: Punch 30: Dice
F: Flange

Claims (4)

A first molding step of cutting the round rod-shaped raw material, receiving the cut molding material in the first dice, and applying a pressing force of the first punch to form a primary molding having webs facing each other on one side at one end; ;
After receiving the primary molded primary molded product in the second dice, the punching force of the second punch is applied to the primary molded product so that the heights of both web portions of the primary molded product are the same in the horizontal direction of both webs. A second molding step of molding each flange portion into a secondary molded article having:
And after receiving the secondary molded product in a third die, applying a punching force of a third punch to the flange portion of the secondary molded product to cut the third molded product to form a yoke-shaped tertiary molded product. The yoke molding method. The method according to claim 1,
And a preforming step of molding the cut molding material into a preform before the molding of the cut molding material into a primary molding. The method according to claim 2,
The preliminary forming step may include: a first preliminary forming step of applying a punching force to the cut molding material to form a first preliminary molded article having a convex portion having a convex shape in a lateral direction corresponding to a web portion;
And a second preliminary molding step of rotating the first preliminary molded article by 180 ° and forming a second preliminary molded article formed by applying a punching force to distinguish the convex portion and the boss portion. . The method according to claim 3,
The second preliminary molding step further comprises the step of forming a rounded corner portion of the convex portion.

Images