JPH07100210B2 - Method for manufacturing link for linking track - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a link using closed forging for manufacturing a crawler belt link used for a bulldozer, a power shovel, or the like.

[Prior Art] A crawler belt link is conventionally manufactured by a method including the steps shown in FIG. There, first, as shown in (a), the round bar 1 is heated, and as shown in (b), the round bar is flattened by swaging forging to form a swaged product 2, and as shown in (c). A hammer or press is used to perform rough staking using the upper and lower dies whose abutting surface is in the center of the swaged product 2 in the height direction, and between the upper and lower dies, the outer burr 3 (burrs that bulges to the outer periphery of the workpiece). The rough forged product 4 protruding is formed, and subsequently, as shown in (d), finish forging is performed by using the upper and lower dies whose abutting surfaces are also in the height direction central portion of the rough forged product 4. , A finished forged product 6 having a final shape and a burr 5 thinner than the burr 3 is formed. Finally, as shown in (e), the outer burr is trimmed and a hole is formed in a necessary portion. The final product 7 is obtained by punching with a punch.

In the above conventional manufacturing method, upset forging is required, and a stamping forging die is used in upset forging, roughing production, and finish forging, and an inner burr (inside the hole of the work, etc. is used in the final step). The burr that bulges out) and the trimming process for the outer burr were required.

[Problems to be Solved by the Invention] However, in the above conventional manufacturing method, since there are many steps due to the presence of the upset forging step, and there is an outer burr on the material in rough forging and finish forging, the upper and lower dies are used. Since the outer burr is also forged, a large pressing force and pressing energy are required, resulting in waste of manufacturing energy, and a trimming process is required due to the outer burr, resulting in a reduction in yield (yield of about 65%). However, there are problems such as an increase in the number of steps. Further, when the outer burr is trimmed, as shown in FIG. 10, the forging flow 8 is cut at the burr removing portion, which causes a crack.

The present invention, in a method for manufacturing a link for linking a crawler belt, reduces the forging process, eliminates the occurrence of outer burrs, reduces the die-casting force and capacity in forging, and eliminates the need for removing the outer burrs in the trimming process. The purpose is to improve the material yield when unnecessary.

[Means for Solving Problems] In the method for manufacturing a crawler belt link according to the present invention for achieving the above object, a heated link material is used in the first step so that the pin side has a larger volume than the bush side. A rough punched shape is formed by distributed closed forging, and a punch provided corresponding to the pin forged, bushed hole, and central window portion is pressed into the closed forged product in the second step to correct excess and deficiency of the material and The variation in weight is constituted by a method in which closed forging is carried out by absorbing the thickness of the inner burr which changes depending on the pushing amount of the punch, and the inner burr portion is punched in the third step.

[Operation] In the method of the present invention described above, the heated link material (for example, a round bar) is closed forged in the first step without being upset forged, and the outer circumference, the upper and lower sides are closed in the second step. The excess and deficiency of the material is corrected (closed forging) by the closed die. For this reason, since there is no outer burr on the work as in the conventional case, trimming of the outer burr is not necessary and only punching is performed by punching. Also,
There is no waste like forging the outer burr with the upper and lower dies. By these, a part of the manufacturing process is removed, and the cost is reduced.

The closed forging is used for forging a connecting rod or the like which is an internal combustion engine component, but is not used for manufacturing a crawler belt link.

[Embodiment] A method for manufacturing a crawler belt link according to the present invention will be described below with reference to FIGS. 1 to 8.

FIG. 1 shows the steps of the method of the present invention. As shown in FIG. 1, in the step (a), the link material 11 made of a round bar or the like (not limited to the round bar) is heated to a necessary temperature or higher, and in the first step (b), Rough punch forging (close forging) is performed by using a closed die (closed rough die) 12 whose outer periphery is constrained to obtain a rough shape of the link. It is preferable that the closing rough die 12 has a positioning means for the link material in the die. This rough link shape is formed on the rough link product 13 in which the pin side has a larger volume than the bush side. Coarse shaped product 13 of the link does not have external burrs on its outer periphery due to closed forging. Therefore, there is no waste of hitting a burr with the upper and lower dies for forging during closed rough forging. As shown in Fig. 1 (b), the rough link product 13
Has a raised portion 14 at the portion to be punched in the final product state, but this is to enable material replenishment to that portion when a lacking portion is about to occur in the next finish forging. The purpose is to make the application of closed forging highly reliable. Next, in a second step shown in FIG. 1C, finish forging for correcting the distribution of the material is performed by closed forging in a die whose outer periphery and upper and lower sides are sealed. Here, the rough-shaped product 13 of the above-mentioned link is placed in a closed finishing die 15 whose outer periphery and upper and lower sides are constrained, and the die is hermetically sealed while being forged by an upper and lower die fitting process. More pin holes,
Push the pin hole, bush, and center window with the punch 16 provided corresponding to the bush hole and center window. For this reason, the material is pushed, and the finished shape product 17 in which the filling is filled by filling the deficient portion is obtained. Since the rough-shaped product 13 has the raised portion 14, there is no shortage of material, and a finished-shaped product 17 with high dimensional accuracy can be obtained. Since it is a closed forging, no external burr is generated even in the finish forging. However, internal burrs are left behind between the punch and the corresponding mold for compensating the material excess and deficiency. Subsequently, as shown in the third step of FIG. 1 (d), the finished shape product 17 is passed to the hole punching process, where the punching punch 18 is used to move to a necessary portion (bush hole, pin hole, central window portion). A hole is opened, and the material (inner burr) remaining in the hole portion is punched out and removed to obtain the link 19 of the final product. At this time, trimming of the outer burr is unnecessary.

2 and 3 show a crawler belt connecting link 19 manufactured by the method of the present invention. The link 19 has four through holes,
Of the two outer holes, the larger hole is the bush hole 21, the smaller hole is the pin hole 20, and the two holes are also in the center for the central window portion 22,
23 is opened.

Of the above-mentioned steps, rough punch forging, finish forging, and hole punching will be described below by adding an apparatus used for carrying out the method.

Figures 4 and 5 show the rough block closed forging die 12 (see Figure 1).
It shows the neighborhood of the type. In the drawing, 24 is an outer peripheral die, 25 is a lower die, and 26 is an upper die. When the link material 11 is forged into a rough-shaped product 13 of the link, the side surface of the rough-shaped product 13 of the link is Since the die and the lower die are closed without making contact with each other, the forging is closed forging, and no outer burr is generated. For this reason,
There is no external burr like in the past, and the phenomenon of hitting the burr with the upper mold and the lower mold does not occur, and all the force acting between the upper mold 26 and the lower mold 25 is concentrated on the rough shaped product 13 and forged. There is no waste of power. This saves power, and the capacity of the device,
It also leads to a reduction in forging power. The raised portion 14 is provided with holes 22 and 23 at the center and holes 20 and 21 on the pin side and the bush side, which are formed later.
Made in the center of.

FIG. 6 shows the vicinity of the die of the closed forging die 15 (see FIG. 1) in the finishing process. In Fig. 6, 27 is an upper mold, 28 is a lower mold, and when the upper and lower molds are combined, a finished product as shown in the figure.
The outer periphery of 17, and the top and bottom are closed. With this blockage completed, the punches 29, 30, 31, 32 (corresponding to the punch 16 in FIG. 1) provided at the positions corresponding to the four holes 20, 21, 22, 23 (corresponding to the punch 16 in FIG. 1) are activated, Press the material of the site to be drilled. At this time, the material removed by the punches 29, 30, 31, 32 is pushed into the space between the rough-shaped product 13 and the finishing die in the vicinity to fill the space and the finished-shaped product 17 is obtained. At this time, there is no shortage of material because of the raised portion 14. In addition, the variation in weight is determined by punch 29, 30, 31, 32 and knockout pin.
38, which can be absorbed by the thickness of the inner burr 37 produced by the molds 27, 28. The punches 29, 30, 31, 32 may be pressed simultaneously, separately or in combination. In the illustrated example, first, the two central holes 22 and 23 are pressed, and then the outer holes 20 and 21 are pressed. By following this order, a more desirable shape can be obtained. Since the finish forging is the closed forging as described above, the outer burr does not occur even in the finish forging, and the waste of pushing the outer burr does not occur. Further, since only the hole portion is pushed by the punch, the pushing force is small compared to the conventional case where the portion other than the hole portion is pushed. still,
It is desirable to divide the upper and lower molds at the connecting intersection point of the R portion of the lower end surface on the product. By doing so, it is possible to prevent the quality of the product from being deteriorated due to the mold deviation.

FIG. 7 shows the punching process. 33, 34, 35, 36 are holes
Punch for punching holes 20, 21, 22, 23 (Punch 18 in FIG. 1
It is possible to punch holes with a small presser by shifting the punching order from each other. Trimming of the outer burr is not necessary because no outer burr is exposed in this process. Since there is no trimming of the outer burr, the link 19 for the crawler belt of the final product is not cut as shown in FIG. 8 in the forging flow 39, and cracks are not generated. Further, since the finishing process type has no draft, machining or pressing of the upper and lower end surfaces can be omitted. In addition, since there is no removal of outer burrs by trimming, the material yield is dramatically improved from the conventional 65% to 90% or more.

[Advantages of the Invention] According to the method for manufacturing the crawler belt connecting link of the present invention, the following effects can be obtained.

I. Since rough forging and finish forging are closed forging, no external burr is generated.

B. Since external burrs do not occur, the forging force required for rough forging and finish forging can be reduced, and the device capacity can be reduced.

C. Since no external burr is generated, the material yield is 90% or more.

D. The swaging forging step that was necessary in the past is no longer necessary.

E. Because closed forging allows forging with a clean outer circumference,
There is no need to machine the top and bottom edges of the product.

F. Since outer burrs do not occur, the grain flows of the outer burrs are not cut, the strength increases, and the occurrence of cracks when a large load is applied during use is significantly reduced.

G. Through the above, cost reduction and product quality improvement can be achieved.

[Brief description of drawings]

FIG. 1 is a perspective view showing steps of a method for manufacturing a crawler belt link according to an embodiment of the present invention, FIG. 2 is a plan view of a crawler belt link link manufactured by the method of FIG. 1, and FIG. 2 is a cross-sectional view taken along the line III-III of the link in FIG. 2, FIG. 4 is a cross-sectional view of a rough punch closed forging die for carrying out the method of FIG. 1, and FIG. 5 is a lower die plane of the apparatus of FIG. Fig. 6, Fig. 6 is a sectional view of a finish closing forging die for carrying out the method of Fig. 1, Fig. 7 is a sectional view of a punching device for carrying out the method of Fig. 1, and Fig. 8 is a method of Fig. 1. FIG. 9 is a cross-sectional view showing a grain flow line of a crawler belt link link manufactured in FIG. 9, FIG. 9 is a perspective view showing steps of a conventional link manufacturing method, and FIG. 10 is a forging process of a crawler belt link link manufactured by a conventional method. FIG. 4 is a cross-sectional view showing streamlines. 11 …… Link material 12 …… Coarse punch forging die 13 …… Coarse shape product 14 …… Raised part 15 …… Finishing block forging die 16 …… Punch punch 17 …… Finishing shape product 19 …… For track link connection Links 20, 21, 22, 23 ... holes

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hamashima ▲ Yoshi ▼ Man 5-5 Yonbancho, Chiyoda-ku, Tokyo 9 Topy Industries Co., Ltd. (72) Teruaki Fujisawa 9-5 Yonbancho, Chiyoda-ku, Tokyo (56) Reference JP-A-58-67572 (JP, A) JP-A-58-26685 (JP, A) JP-A-55-76768 (JP, A) JP-A-58-44943 (JP, A) Japanese Patent Publication 3-79097 (JP, B2)

Claims (1)

[Claims] 1. A heated link material is formed into a rough hit shape by closed forging in which a pin side has a larger volume than the bush side in the first step, and a pin hole, a bush hole is formed in the closed forged material in the second step. By pressing a punch provided corresponding to the central window portion, the excess and deficiency of the material is corrected, and the variation in the material weight is absorbed by the thickness of the inner burr which changes depending on the punch pressing amount. A method for manufacturing a crawler belt link, wherein the inner burr portion is punched.