JPS6277143A - Forging method - Google Patents

Abstract

PURPOSE:To prevent the generation of a defect such as a burr, a contact flaw, etc., and to obtain a product having a good quality by manufacturing an intermediate product by using a fully enclosed die forging method, and thereafter, forming a prescribed recessed part in a boss part by a push-in forming. CONSTITUTION:A metallic die 10 is opened, also a heated material steel ingot 19 is set to the center position of cavities 12a, 17a, and thereafter, a punch 13 is made to descend and the steel ingot 19 is crushed, by which an intermediate product 18 is formed. Therefore, the metallic die 10 is opened, and the intermediate product 18 is detached from the metallic die 10. Subsequently, the heated intermediate product 18 is placed in cavities 22a, 24b of a metallic die 20, and a punch 25 is made to ascend and pushed into the intermediate product 18 by a prescribed depth. A recessed part is formed in the intermediate product 18, also a projecting part 26a by an excess thickness generated due to the formation of the recessed part is formed, and the intermediate product 18 becomes a work 26 as a forging product. As for the work 26, the center part of the boss part is punched in the subsequent working process, a machining is performed, and a knuckle spindle is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention includes a boss portion and an arm projecting outward in the radial direction from the boss portion. The present invention relates to a forging method suitable for manufacturing a product having a concave portion on the protruding end portion.

(Prior Art) This type of forged product includes, for example, a semi-finished knuckle spindle product having a profile dimension required for a knuckle spindle that functions to support the axle of a steering wheel of an automobile.

This workpiece, illustrated as 1 in FIG. 4, has a substantially cylindrical boss portion 1a with one end portion in the axial direction having a larger diameter than the other end portion, and a large diameter side (in the figure) of the boss portion 1a. Three arms 1b to 1d project diagonally outward in the radial direction (diagonally downward in the figure) from the outer periphery of the end portion on the lower side, and approximately horizontally outward in the radial direction from the outer periphery of the end portion on the large diameter side. and a boss portion 1a shown here.
has one recess at its large-diameter end, and a recess 19 concentric with the recess 1t but smaller in diameter at its small-diameter end, and between these recesses 1f and 1g. It has a partition wall 1h.

Then, the workpiece as a knuckle spindle semi-finished product forged into such a shape is then formed into a knuckle spindle by punching out the partition wall 1h as shown in FIG. 5 and particularly machining the inner peripheral surface of the boss part. Ru. Incidentally, in order to attach such a knuckle spindle to an automobile body, a bearing that supports the axle of the steering wheel is fitted inside the boss part, and a bearing that supports the axle of the steering wheel is fitted inside the boss part.
This is done by connecting the lower end of the strut, the steering wheel blonde, and the transverse link, respectively, and further attaching a brake mechanism to the flange 1e.

By the way, as illustrated in FIG. 6, the work 1 as described above is generally directly divided into a portion 2a that becomes the work 1.
In addition, the workpiece 1 is manufactured by press forging a forged product 2 having a burr 2b integrally formed around the forged product 2, and then removing the burr 2b from the forged product 2. When manufacturing, it is necessary to remove a large part of the processed material as burr 2b, resulting in a poor material yield and a lot of energy being wasted to heat the material. There was a problem that the cost of work 1 was high.

Therefore, closed forging has been attempted in the past as a method to solve this problem. Here, closed forging refers to placing a steel ingot with a volume almost equal to the volume of the product in the center of a closed mold cavity, and then pushing a punch into the material, or This is a forging method that causes the material to flow to the surrounding area of the cavity by crushing it with a punch, spreading the material to every corner of the closed cavity. Because forging is done without
The above-mentioned problems do not occur.

(Problems to be Solved by the Invention) However, with closed forging as described above, the amount of material flowing in the closed mold cavity becomes extremely large, so this forging method When applied to the production of workpieces, when material flows from the center of the mold cavity to the cavity part that contributes to the formation of the arm, it surrounds the concave part of the boss part and continues to the base of the arm. In the recessed part of the cavity that forms the part that is Conventionally, such a method could not be put to practical use because of the problem that it was not possible to obtain a workpiece 1 of high quality.

The present invention provides a method by which products of good quality can be manufactured at low cost.

(Means for Solving the Problems) The forging method of the present invention includes a boss portion and an arm protruding radially outward from the boss portion, and the boss portion extends from the protrusion of the arm in the axial direction of the boss portion. When forging a product having a concave portion in the side end portion, an intermediate product having a substantially columnar center portion and an arm of a predetermined shape and size protruding from this center portion is formed by closed forging, and then The method is characterized in that the recess is formed in the central portion of the intermediate product and forged into a boss having a predetermined shape and size.

(Function) In this forging method, in the first closed forging process, an intermediate product is formed that has a substantially columnar central part and arms of a predetermined shape and dimensions protruding from the central part, and this forging process Since the concave part of the boss part is not formed in this closed forging, the material flows into the arm forming part of the mold cavity extremely smoothly, and there is no dead metal or dead metal in the intermediate product. There is no risk of scratches occurring. And here, in the next forging process, a recess is formed in the center of the intermediate product by push-forming to provide a boss with a predetermined shape and dimensions. The result is a product of good quality with no defects or flaws.

Therefore, according to this method, it is possible to apply the closed forging method to the production of forged products having the above-mentioned shape, and it is possible to prevent the occurrence of flaws and bring about a significant reduction in product cost. Moreover, deterioration in product quality can be reliably prevented.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

Fig. 1 shows an embodiment of the forging method of the present invention, in which Fig. 1(a) shows a die used in the closed forging process, and Fig. 1(b) shows a die used in the subsequent forging process. The left half of these figures shows the state before molding the workpiece, and the right half shows the state after molding the workpiece.

10 in FIG. 1(a) shows the entire closed forging die,
This mold 10 consists of an upper mold 10a and a lower mold 10b.

Further, 11 indicates an upper holder for the upper mold 10a, and here, a through hole 11a is provided in the center of the upper holder 11, and an upper die 12 is fixed to the lower surface thereof.

A recess 12a having the same diameter as that of the through hole 11a is formed at the upper end of the upper die 12, and a cavity 12a is formed at the lower end thereof, and the cavity 12a and the recess 12b are connected to each other. A vertical through hole 12c is provided in the middle part of the upper die 12.

Here, a hollow punch 13 having a flange at the upper end is slidably arranged in the through hole 12c, and a knockout bottle 1 is placed in the through hole 13a of the punch 13.
A return spring 15 is inserted between the spring seats of the punch 13 and the knockout bottle 14 to urge the knockout bottle 14 upward relative to the punch 13. Upper die 12,
The punch 13, knockout bottle 14, and return spring 15 constitute an upper die 10a.

In addition, here, the lower die 1 fixed to the upper surface of the lower holder 16 is shown.
By forming a cavity 17a aligned with the cavity 12a at the upper end of the lower die 17 and the lower holder 16, and providing through holes 17b and 16a that are continuous with each other and open to the cavity 17a, A lower mold 10b of the mold 10 is configured.

In the mold 10 configured in this way, when the upper die 12 and the lower die 17 are in close contact with each other, the cavities 12a and 17a
can be accurately aligned with each other, and under such alignment state, the punch 13
reaches its lower limit position, and the knockout bin 1
4 is located in the same plane as the lower end surface of the punch 13,
Furthermore, the upper end surface of the bolster side knockout rod, which will be described later, is inserted into the through holes 16a and 17b into the cavity 17.
When located in the same plane as the top surface of a, the upper and lower molds 10
Between a and 10b, there is a boss portion 1a of the workpiece 1 shown in FIG.
an arm (for example, arm 18b) having the same size and shape as the arms 1b to 1d projecting diagonally downward from the center portion, and a flange having the same size and shape as the flange 1e. A cavity is defined that is shaped and dimensioned to form an intermediate product 18 having the shape and dimensions.

In addition, 20 in FIG. 1(b) is a concave portion 1f of the workpiece 1 shown in FIG. A mold for forming a concave portion having the same shape and dimensions as shown in FIG.

In the figure, 21 indicates an upper holder for the upper mold 20a of the mold 20, and here, the upper holder 21 is provided with a through hole 21a,
A cavity 22a is provided at the lower end of the upper die 22 fixed to the lower surface thereof, and a vertical through hole 22b is provided at the upper end to communicate the cavity 22a with the through hole 21a of the upper holder 21. 20a
Configure.

In the figure, 23 indicates a lower holder for the lower mold 2Ob of the mold 20,
Here, a through hole 23a is provided in the center of the lower holder 23, and a lower die 24 is fixed to the upper surface of the lower holder 23. Further, here, a cavity 24a is formed at the upper end of the lower die 24, and a recess 24a continuous to the through hole 23a is formed at the lower end of the lower die 24.
4 is provided with a vertical through hole 24c that communicates the cavity 24a with the recess 24b, and in addition, a cylindrical punch 25 having a flange at the lower end is slidably disposed in the through hole 24c. By bending, the lower die 24 and punch 25 constitute a lower die 20b.

In such a mold 20, the lower surface of the upper die 22 and the lower die 2
In this close contact state, the upper surface of the cavity 22a and the cavity 24a can be accurately aligned, and while maintaining this alignment, the punch is inserted as shown in the half of the inner cloth in FIG. 1(b). 25 as its upper limit position, and the upper end surface of the punch 25 and the through hole 25a of the punch 25.
The upper end surface of a bolster-side knockout rod (to be described later) inserted into the cavity 22a is positioned on the same plane, and
When the upper end surface and the lower end surface of a later-described ram-side knockout rod inserted into the through hole 22b of the upper die 22 are located in the same plane, the upper and lower molds 20a and 20b
A convex portion 26a having approximately the same volume as the concave portion 1f extends from a portion of the workpiece 1 shown in FIG. 4 that corresponds to the small-diameter shaft end edge of the boss portion 1a.
defines a cavity in which a workpiece 26 with a protruding state can be formed.

Forging using the mold 1o and the mold 20 described above can be performed as follows.

First, the upper holder 11 is attached to a main ram (not shown) of a press machine, and the lower holder 16 is attached to a bolster (not shown) of the press machine, with the upper and lower dies 10a and 10b facing each other, and then the punch is attached. The upper end flange of 13 is attached to the inner ram 31 of the press machine, and the lower end of the ram-side knockout rod 32 in this inner ram 31 is brought into contact with the upper end of the knockout bin 14, and further, the bolster-side knockout rod of the press machine is attached. 33 is inserted into the through hole 17b of the lower mold 10b, and the upper end surface of the knockout rod 33 is positioned in the same plane as the top surface of the cavity 17a at its lower limit position.

Next, such a mold 10 is opened based on the rise of the main ram of the press machine, and the mold 10 is opened as shown in FIG. 1(a).
As shown in the left half of the figure, after setting one heated steel ingot approximately in the center of the cavities 12a and 17a,
The mold 10 is closed as shown in the figure, and the punch 13 is moved as shown in FIG. 1(a) by lowering the inner ram 31.
Lower the material steel 119 to the lowering limit position shown on the right half of the
by crushing the material into the cavity 12
a, the above-mentioned intermediate product 1 by flowing it to every corner in 17a
form 8. That is, the intermediate product 18 is produced from the material steel ingot 19 by closed forging.

Incidentally, since the intermediate product 18 formed here does not have a part corresponding to part A of the work 1 shown in FIG. The flow into the parts will be extremely smooth, and the intermediate product 18 will be of good quality without dead metal or defects.

Then, based on the rise of the main ram, mold 10
The mold is opened, and at the same time, the knockout rods 32 and 33 are respectively projected, and the intermediate workpiece 18 is removed from the mold 10.

When performing the forging process using the die 20, first, the upper holder 21 and the lower holder 23 are attached to the main ram and bolster of another press machine. In addition, the lower end flange of the punch 25 is attached to the inner ram 41 located on the bolster side of the press machine, and the bolster side knockout rod 4 protrudes from the inner ram 41.
2 is inserted into the through hole 25a of the punch 25 so that its upper end surface is located in the same plane as the upper end surface of the punch 25, and further,
The lower end surface of the ram-side knockout rod 43 is located in the same plane as the upper end surface of the cavity 22a.

Cavity 22a12 of mold 20 set in this way
4b, the heated intermediate product 18 is placed in the same manner as described for the mold 10, and the subsequent inner
Based on the rise of the ram 41, the punch 25 is moved as shown in FIG. 1(b).
Raise it to the upper limit position shown on the right half of the screen.

As a result, the punch 25 is pushed into the intermediate product 18 by a predetermined depth, and a recess having the same shape and dimensions as the recess 1g of the workpiece 1 is formed in the intermediate product 18.
Convex portion 26a due to excess thickness caused by formation of this concave portion
is formed, and the intermediate product 18 becomes a workpiece 26 as a forged product. That is, the workpiece 26 is formed by closed forging of the intermediate product 18.

Then, by opening the mold 20 and protruding the knockout rods 42 and 43, the workpiece 2
6 is removed from the mold 20 by m.

The workpiece 26 formed in this way will be processed in the same way as the workpiece 1 shown in FIG.
A knuckle spindle can be obtained by punching out the central portion of the boss portion including a and then performing machining.

As mentioned above, in this example, by performing two-step closed forging using the material side 19 as the starting material, the workpiece 1
A boss portion 1a and portions corresponding to arms 1b to 1d protruding obliquely outward in the radial direction from the boss portion 1a, and the boss portion corresponds to a predetermined recess 1t at an end portion on the arm protruding side in the axial direction. Since it is possible to form the desired workpiece 26, in other words, a forged product, which has a part that has will be brought about. Moreover, since the concave portion at the end of the boss portion of the workpiece 26 is formed by pressing the punch 25, there is no possibility that the workpiece 26 will have dead metal or scratches as described with reference to FIG. do not have.

FIG. 2 is a sectional view showing another embodiment of the invention.

Here, as shown in FIG. 2(a), instead of the punch 13 of the upper die 10a shown in FIG. 1(a), a punch 40 having a downward protrusion 40a is installed at the center of the lower end portion. ,
Also, as shown in FIG. 2(b), FIG. 1(b)
Instead of the upper die 22 shown in FIG.
An upper die 41 having a cavity 41a having a shape corresponding to
In addition, by lowering the upper end surface of the bolster-side knockout rod 42 sufficiently from the upper end surface of the punch 25 during the formation of the workpiece 28, it is possible to define a relief portion 25b for excess thickness at the upper end portion of the punch 25. .

When forging is performed using such a die 10 and die 20, first, a second steel ingot is drawn from a steel ingot 19 using the die 10 shown in FIG. 2(a) in the same manner as in the embodiment described above.
An intermediate product 27 shown on the right side of FIG. [a] is formed by a closed forging method. The intermediate product 27 formed in this way is
Although it has almost the same shape as the workpiece 1 shown in FIG. 4, it does not have a portion corresponding to the recessed portion 1f. In other words, it does not have a portion corresponding to the shoulder portion shown by A in FIG. 7. Therefore, during the closed forging, no dead metal or flaws will occur in the intermediate product 27.

Next, using the mold 20 shown in FIG. 2(b), the above-described workpiece 28 shown in the right half of FIG. 2(b) is formed from the intermediate product 21 in the same manner as in the embodiment described above.

In this forging process, the upper end surface of the bolster-side knockout rod 42 is positioned sufficiently lower than the upper end surface of the punch 25 to define a relief part 25b for excess thickness at the upper end portion of the punch 25. The excess thickness generated by the push-forming by 25 freely escapes into the relief portion 25b of this excess thickness to form the convex portion 28a. That is, here, the workpiece 28 is produced from the intermediate product 27 without using closed forging.
will be formed.

The workpiece 28 formed in this way is also formed into a knuckle spindle by treating the central part of the boss part including the convex part 28a and then machine-machining it in the same manner as the workpiece 1 shown in FIG. can do. Therefore, in this example, similar to the above-mentioned example, closed forging eliminates the occurrence of flaws, resulting in a significant reduction in product cost. In addition, since the second forging process is performed without blocking the workpiece, the required punch pressure can be reduced to approximately half of the required punch pressure for the second process in the example described above. The tightening force can also be greatly reduced, and restrictions on the press machine used in this process can be reduced.

FIG. 3 is a cross-sectional view showing still another embodiment of the present invention. In this example, in the first forging process, as shown in the right half of the figure, a Although the intermediate product 29 has a shape, an intermediate product 29 having a hollow part 29a is formed at the shaft end portion corresponding to the part forming the predetermined recess 1g of the workpiece 1. For this reason, here we use Figure 1 (
In a lower mold 10a similar to that shown in FIG. 2(a) and FIG. 2(a), a smoothly rising convex portion 17c is formed in the center of the cavity 17a.

In the method of this example, two intermediate products are formed by closed forging using such a die 10, and then these two intermediate products are made into a workpiece 28 using a die 20 shown in FIG. 2(b). According to the method, the excess meat produced in the second step can be reduced compared to the above-mentioned example under the action of the thinned-out portion 29a, so in addition to the effect described in connection with FIG. 2, material costs and product costs are also reduced. This can lead to a further decrease in

Although the present invention has been described above based on the illustrated examples, the molds illustrated in the illustrated examples can also be used with the upper mold and lower mold reversed.

The forging method of the present invention can be applied not only to the production of the knuckle spindle semi-finished products described above, but also to the production of forged products such as wheels.

(Effects of the Invention) Thus, according to the forging method of the present invention, after producing an intermediate product using the closed forging method, by forming a predetermined recess in the boss portion by push-forming, not only the occurrence of defects but also the Good quality forged products without defects such as scratches and dead metal can be manufactured at low cost.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing an example of a mold used for carrying out this invention, FIGS. 2 and 3 are longitudinal cross-sectional views showing other examples of a mold used for carrying out this invention, and FIG. A diagram showing a knuckle spindle semi-finished product as an example of a forged product, FIG. 5 is a sectional view showing the manufacturing process of the knuckle spindle, FIG. 6 is a perspective view showing a conventional knuckle spindle semi-finished product, and FIG. 7 is a knuckle spindle semi-finished product. FIG. 3 is a partially enlarged sectional view of the product. 10, 20...Mold 10a, 20a...Upper die 10b, 20b...Lower die 18, 27.29...Intermediate product 26, 28...Work Figure 1 (a) η 1st Figure (b) Figure 2 (a) Figure 2 (b)

Claims (1)

[Claims] 1. When forging a product comprising a boss part and an arm protruding radially outward from the boss part, the boss part has a recess in the end portion on the protruding side of the arm in the axial direction. a closed forging step of forming an intermediate product having a columnar central portion and an arm of a predetermined shape and size protruding from the central portion; and forming the recess in the central portion of the intermediate product to form a predetermined A forging method characterized by sequentially performing a forging step to obtain a boss portion of the shape and size.