US2599706A

US2599706A - Method for forging

Info

Publication number: US2599706A
Application number: US679538A
Authority: US
Inventors: John H Friedman
Original assignee: National Machinery Co
Current assignee: National Machinery Co
Priority date: 1946-06-26
Filing date: 1946-06-26
Publication date: 1952-06-10
Anticipated expiration: 1969-06-10

Description

June 10, 1952 J. H. FRIEDMAN 2,599,706

1 Fig; 2

IN R. JOHN H FE/EDMAN VENTO 4; i ATI'OPN .q

June 10, 1952 J. H. FRIEDMAN 2,599,706

METHOD FOR FORGING Filed June 26, 1946 4 Sheets-Sheet 5 INVENTOR. JOHN H FP/EDMA/V A TTOBNEYQ June 10, 1952 J. H. FRIEDMAN METHOD FOR FORGING 4 Sheets-Sheet 4 Filed June 26, 1946 INVENTOR. JOHN F? 'DMA/V Patented June 10, 1952 METHOD FOR FORGING John H. Friedman, Tifiin, Ohio, assignor to The National Machinery Company, Tiifin, Ohio, a corporation of Ohio Application June 26, 1946, Serial No. 679,538

This invention relates to a method and apparatus for forging, more particularly to an improved and novel method and apparatus for hot forging a vehicle hub.

The method and apparatus to be described in thefirstdie; herein is particularly adapted wherein the forg- Fig. 4 shows the blank made at the second die; ing is done on what is commonly referred to as a Fig. 4a is a section taken on Fig. 4; forging machine, these machines usually having Fig. 5 shows theblank made at the third die; the characteristic that each operation must be Fig. 5a is asection taken on Fig. 5; done with one blow, rather than using repeated Fig. 6 shows the fourth and last die after it blows to produce a blank of a given shape. has closed on the blank made in the third die; Since the number of operations which can be Fig. 7 is a section taken on Fig. 6 showing how performed on a given forging machine is relathe sliding dies are mounted; and tively limited, the forging of an article like a Fig. 8 shows the completion of the stroke and vehicle hub, which has a large flange and which the part made in the fourth and last die. has a large aperture from end to end, has pre- In Fig. 1 a cylindricalbar S is shown inserted sented serious problems because the large amount between the split die pieces D1 against the stop of metal which must be displaced from cylindri- A which may be swung down in place. Each die cal or bar stock has heretofore made it imprachalf D1 is bored as at I so that the closed die will tical to forge such a hub on the conventional grip the stock inthat vicinity. Each die part type forging machine. It is an object of the also has an enlarged pocket 2; a convex nose 3 present invention to displace the required which merges with the tapered bore 4 and a cutamount of metal in relatively few operations ting and gripping flange 5 which merges with the without need for excessive force or repeated clearance bore 6, bore 6 being large enough to blows at any station. receive the tongs which grip the stock. When I have found that the prior practice of fiangthe dies are closed on the stock, it is frictionally ing the blank first, while the heat of the piece gripped by wall I and the nose part 3 reduces the is high, has made it difficult to punch the blank section of the blank and aids in firmly retaining thereafter, the result being that excessive force it. i and repeated blows were required to produce the In Fig. 2 the dies have closed on the stock, article. I have devised a novel tool and die apfrictionally gripping it as at l, deforming it and paratus and method of using the same which restricting its section at 3, and the flange 5 has permits me to first punch the blank while the necked down stock as at l forcing back a portion heat is high but which retains the heat in that 8 which provides means for tongs to grip'the section of the blank to be flanged, so that the blank. The action of the convex part 3 also second operation can be a fianging operation elongates the blank outwardly as can be seen without need for reheating, excessive force or by comparing Figs.1and 2. repeated blows to make the flange. Fig. 2a. shows theshape of the necking flange I have also found that after the flange is 5, and the adjacent blank portion 1. It can be formed the final punching and forming of the seen that the neck 1 of the blank is non-circular tubular part of the article tends to warp and 40 in cross section and this is also true of the section deform the flange itself. It is another object taken in 2b as can be seen in that figure. of this invention to remove any such distortion In Fig. 3 the first tool T1 has pierced the blank, of the flange by providing sliding die portions the tool having a conical nose I 0 terminating in so arranged that near the end of the final stroke a rounded portion ll. When this piercing operthe sliding dies flatten and remove all distortion ation takes place the blank heat is still high and of the flange, even though a punching and formmetal displaced by the tool flows into the pocket ing operation is carried out up on the tubular 2, this displaced metal being indicated generally hub body. at l2. It will be noted that there is a clearance These and other objects and advantages will space l3 between the hot metal of the blank and be apparent as the following detailed description the die, this arrangement being such that the of my invention proceeds. portion of the blank which is to befiangecl is In the drawings: maintained at a relatively high heat level be- Fig. 1 shows the blank inserted against the cause,-contrary to conventional practice, th die stock with the first set of dies spread to receive does not conduct any great amount of heat away the blank; from this portion of the blank. It is important 6 Claims. (Cl. 7881) 2 Fig. 2 shows the first set of dies closed on the blank;

Figs. 2a and 2b are sections taken on Fig. 2; Fig. 3 shows the first tool piercing the blank to note, and it is a novel feature of my method and apparatus, that the strong frictional gripping of the side walls of the blank at the area I, prevents extrusion of metal out of the die. Also, the restriction caused by convex portion 3 of the die helps to cause displaced metal flow into the die pocket.

The blank made in the first die has been labeled O1 and at the completion of the first stroke the split dies D1 are opened and the piece 01 is positioned between the split dies D2 as shown in Fig. 4. The tool at this station has a flanging head I6 which is apertured as at [4 to receive a roundnosed piercing tool 15, the piercing tool bein secured in the tool by any convenient fastening means a. vided between the tool 15 and a block [6 which carries it, to permit the tool to further punch and form the cylindrical'portion ll of the hub blank. A die at the second station is formed with a tapered wall Ha to grip the corresponding portion of the blank and each of the die parts has gripping flanges l8 which further neck down and grip the blank at I 8:1. as the die is closed. When the blank 01 is positioned in the die, it may be turned 90 from its previous position so that the wide portion 1 shown in Fig. 2a .is necked down and reduced in section to form the neck lBa shown in Fig. 4a to firmly grip the blank.

As the tool T2 is forced against the blank, the metal which was adjacent the portion l2 of the blank in Fig. 3 is forced out to form the flange l9 and this operation isusually accompanied by a shortening of the blank plus a slight additional amount of piercing thereof by the punch 15. It is noted that the tool T2 telescopes with the die D2 to entirely confine the metal duringthe flanging operation so that the shape of the blank may be accurately controlled.

The blank Oz is then turned 90 and placed in the third pair of dies for further piercing and fianging. The tool T3, as shown in Fig. 5, is apertured as at to receive the piercing punch 2| which is retained by fastening means such as shown at .22. The face of the tool at 23 is shaped to produce a finished flange. The retaining flange 24 on each die part D3 further necks down the portion of the blank to form a relatively small neck 2411 which may be circular and which can be seen in. Fig. 5a. The punch 2| extends still further into the blank in the third operation and it will be noted that the bore in'the die 21 is cylindrical as opposed to the conical shape Ila shown in Fig. 4. This provides space into which the metal displaced by the punch 2| can flow because the blank was initially conical in this area. I also prefer to slightly shorten the hub portion 25 during this operation.

In Fig. 6 the blank 03 made in the third die has been positioned between the dies D4 and the dies have closed about the blank. Dies D4 contain a pair of sliding dies 28, these dies being mounted in the die block housing 28a and retained by suitable retaining means such as the flange shown at 29. As can be seen in Fig. '7, each sliding die 28 is kept from falling out of housing 28a by means of keys 30 and is urged against the retaining means 29 by a set of springs 3|. The sliding die may have a bore 32 which communicates with a larger bore 33 so that what will be the inboard hub portion can be made larger in diameter in order to receive the necessary bearingsin the assembled device. The

An annular space is thereby prodies are recessed as at 34 to provide clearance for the tool and the sliding dies have an abutment shoulder 35. When the dies D4 first close on the blank 03 the springs move the sliding dies away from the blank so that the flange straightening face 36 is spaced from the blank flange 26 as indicated at 38. A flange 39 is formed on each die of sucha diameter that the wall diameter of flange 39 is equal to the inner diameter of what is to be the adjacent bore through the hub barrel. 7

In Fig. 8 tool T4 has completed the forging. The removable punch 40 has a cylindrical extension M which, in conjunction with the flange 39 of the die, punches out the metal as at 46. As the tool T4 advances it form an enlarged diameter portion on the blank by forcing the metal at that point radially against the wall 33 of the sliding dies. As mentioned above, towards the end of the stroke the punch end 4| passes through the aperture 39 in the die to punch out the slug of stock 46.

In punching operations of this nature the tendency of the flange 26 to dish or buckle makes for an inaccurate forging unless the flange is straightened. Such straightening is accomplished during the last part of the forging stroke at which time the abutment shoulder 43 on the tool T4 strikes the abutment 35 on the sliding dies and takes up all the clearance shown at 38 in Fig. 6. When this occurs the face 36 of l the sliding die is pressed against the flange 26 of the blank so that the blank is flattened, preventing the occurrence of buckling or distortion during the final plunging stroke. The actual amount of motion of the sliding die relative to the die housing may be relatively small. For example, I have found that a clearance of approximately .040" works satisfactorily.

Having completed the detailed description of my invention, those skilled in the art will appreciate that my novel method and apparatus permits forging of a flanged hollow article without developing excessive pressures and without reheating between operations. The provision of a cavity or pocket to receive the metal adjacent the flange part as shown in Figs. 1-3 retains enough heat for ready flanging, and also makes it possible to do the initial punching while the blank heat is high. Likewise, the provision of a cylindrical pocket 27 in the third die to receive the tapered blank portion permits further piercing without forcing excess metal into the flange where it is not desired.

Likewise, the provision of the novel sliding die assembly used in connection with the apparatus I have disclosed makes it possible to forge an accurately shaped hub with a flange which is flat and true. Although I have described my apparatus and method in connection with making a wheel hub, those skilled in the art will appreciate that any pierced flanged article could be forged on a forging machine in accordance with the principles and methods disclosed and described. The exact shape of the tools and die cavities depends largely upon the article to be manufactured and if the principles described, in the specification are followed variations in the tools and dies than that illustrated in the specification can be made without departing from the spirit of my invention. I also contemplate that many useful articles could be made without afiecting all of the steps herein described.

Having thus described the present invention so that others skilled in the art may be able to understand and practice the same, I state that What I desire to secure by Letters Patent is de fined in what is claimed.

What I claim is:

1. The method of forging an elongated heated metal blank comprising the steps of confining one end of the blank in a die and preventing axial motion thereof, guiding the other end of the blank while leaving an intermediate portion unconfined, piercing the blank from it guided end to cause metal to fiow axially ahead of the tool and gather radially outwardly at said unconfined intermediate portion with a substantial portion of said intermediate gathered portion being unconfined throughout said piercing step, confining said one end of the blank in another die, and shortening said blank from said other end with its previously gathered midsection radially unconfined while upsetting the metal of said previously gathered midsection radially outwardly to form a flange.

2. The method of forging an elongated heated metal blank comprising the steps of confining and necking down one end of the blank in a die to elongate the blank and prevent axial motion thereof, guiding the other end of the blank while leaving an intermediate portion unconfined about its circumference, and piercing the blank from its guided end to cause metal to flow axially ahead of the tool and gather radially outwardly at said unconfined intermediate portion with a substantial portion of said intermediate gathered portion being unconfined throughout said piercing step.

3. The method of forging an elongated heated metal blank comprising the steps of confining and necking down one end of the blank in a die to elongate the blank and prevent axial motion thereof, guiding the other end of the blank while leaving an intermediate portion unconfined, piercing the blank from its guided end to cause metal to flow axially ahead of the tool and gather radially outwardly at said unconfined intermedi-- ate portion with a substantial portion of said intermediate gathered portion being unconfined throughout said piercing step, confining said one end of the blank in another die, and shortening said blank from said other end with its previously gathered midsection radially unconfined to shorten the blank and upset the metal of said previously gathered midsection radially outwardly to form a flange.

4. The method of forging an elongated heated metal blank comprising the steps of confining one end of the blank in a die and preventing axial motion thereof, guiding the other end of the blank while leaving an intermediate portion unconfined, and piercing the blank from its guided end to form a recess in the blank and cause metal to flow axially ahead of the tool and gather radially outwardly at said unconfined intermediate portion with a substantial portion of said intermediate gathered portion being unconfined throughout said piercing step, confining said one end of the blank in another die, and enlarging said recess in the blank while shortening said blank from said other end with its previously gathered midsection radially unconfined while upsetting the metal of said previously gathered midsection radially outwardly to form a flange.

5. The method of forging an elongated heated metal blank comprising the steps of confining one end of the blank in a die and preventing axial motion thereof, guiding the other end of the blank while leaving an intermediate portion unconfined, piercing the blank from its guided end to cause metal to fiow axially ahead of the tool and gather radially outwardly at said unconfined intermediate portion with a substantial portion of said intermediate gathered portion being unconfined throughout said piercing step, confining said one end of the blank in another die, shortening said blank from said other end with its previously gathered midsection radially unconfined while upsetting the metal of said previously gathered midsection radially outwardly to form a flange, confining said one end of the blank in another die, and simultaneously piercing said blank and flattening the flange thereof.

6. The method of forging an elongated heated metal blank comprising the steps of confining and necking down one end of the blank in a die and preventing axial motion thereof, guiding the other end of the blank while leaving an intermediate portion unconfined, piercing the blank from its guided end to form a recess and to cause metal to flow axially ahead of the tool and gather radially outwardly at said unconfined intermediate portion with a substantial portion of said intermediate gathered portion being unconfined throughout said piercing step, confining and further necking down said one end of the blank in another die, shortening and further piercing said blank from said other end with its previously gathered midsection radially unconfined while upsetting the metal of said previously gathered midsection radially outwardly to form a flange, confining said blank in another die, and flattening said flange and punching out the necked down portion thereof.

JOHN H. FRIEDMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 761,778 Mercader June 7, 1904 862,641 Jones Aug. 6, 1907 1,668,442 Wineman May 1, 1928 1,913,492 Lefere June 13, 1933 1,929,802 Brauchler Oct. 10, 1933 1,946,117 Sparks Feb. 6, 1934 2,268,246 Dooley Dec. 30, 1941 2,342,021 Swanson Feb. 15, 1944 2,368,695 Wilber Feb. 6, 1945 FOREIGN PATENTS Number Country Date 43,934 Germany Sept. 10, 1910