JPH07115112B2 - Link plate manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a link plate which is a component such as a roller chain and a manufacturing method thereof.

[Conventional technology]

In general, a roller chain is configured by connecting adjacent link plates to each other with a pin, and arranging rollers between the link plates arranged opposite to each other.

Conventionally, a link plate of such a roller chain is formed by fine blanking for punching a plate material 11 as shown in FIG. 15, for example.

However, in such fine blanking,
Since the link plate 13 is punched out from the plate material 11, there is a problem that the yield of the material is poor, and the plate thickness of the plate material 11 is varied, which causes variation in the plate thickness of the link plate 13.

Therefore, for example, as shown in FIGS. 16 and 17, manufacturing a link plate by cold forging has been studied.

In the manufacturing method of FIG. 16, a rod-shaped material 15 is formed into a plate material 17 by upsetting of outer periphery restraint, and then a through hole 19 is formed by piercing, and the manufacturing of FIG. According to the method, a rod-shaped material 15 is formed into a plate material 21 by upright processing that does not constrain the outer periphery, a peripheral body is trimmed to form a plate body 23, and then a through hole 19 is formed by piercing.

[Problems to be Solved by the Invention]

However, in the manufacturing method of FIG. 16, the rod-shaped material 15
, Because it is formed into the plate material 17 by the upsetting process of the outer peripheral constraint, there is a problem that the plate thickness of the link plate is changed due to the variation in the weight of the material 15, and because it is the upsetting process of the outer peripheral constraint, Since it is a closed forging, there is a problem that the molding load is high and the die life is short. Further, in this manufacturing method, burrs may be generated on the outer peripheral portion of the link plate during upsetting of the outer peripheral restraint, and as shown in FIG. 18, a defective portion 25 such as a fold may occur.

Further, in the manufacturing method shown in FIG. 17, it is necessary to trim the outer circumference, which causes a problem that scrap is generated and the yield is low.

On the other hand, in such a link plate, the plate thickness is particularly problematic in both side portions of the link plate in which the through holes 19 are formed, and the plate thickness in the middle portion is relatively unproblematic.

The present invention solves the above-mentioned problems, and it is possible to process with a relatively small molding load, and it is possible to significantly reduce the variation in the plate thickness on both sides of the link plate as compared with the prior art. And a method for manufacturing the same.

[Means for Solving the Problems]

The method of manufacturing a link plate according to claim 1, wherein a preform process of processing the bar into a flat plate shape, and a flat plate processed in the preform process have a small plate thickness in the middle part toward both sides of the flat plate. And a forming step of forming the tapered surface of the tapered flat plate processed in the upsetting step into a flat surface having an equal plate thickness.

In the method for manufacturing a link plate according to a second aspect of the present invention, the bar is processed into a flat plate shape, and tapered surfaces are formed on both sides of the bar so as to incline toward the middle part so that the plate thickness of the middle part becomes smaller. And an shaping step of shaping the tapered surface of the tapered flat plate processed in the upsetting step to form a flat surface having an equal plate thickness.

Further, in the method for manufacturing a link plate according to claim 3, in the method according to claim 1 or 2, the forming step is performed by forming an intermediate portion of the tapered flat plate into an unconstrained portion having a width narrower than both side portions. The part absorbs the weight variation of the material at the time of molding, and improves the dimensional accuracy of the plate thickness of both sides of the tapered flat plate.

[Action]

In the link plate manufacturing method of claim 1, after the raw material is processed into a flat plate shape in the preforming step, the plate thickness of the middle portion is reduced toward both sides of the flat plate by the upsetting step. A tapered surface is formed so that
After that, the tapered surface of the tapered flat plate is molded by the molding step to be a flat surface having the same plate thickness. Further, claim 2
In the manufacturing method of the link plate of, by the upsetting step, the material is processed into a flat plate shape, and a tapered surface is formed that is inclined toward the intermediate portion so that the plate thickness of the intermediate portion becomes small, and thereafter, In the forming step, the tapered surface of the tapered flat plate is formed into a flat surface having the same plate thickness.

Further, in the method for manufacturing the link plate according to claim 3, the forming step is performed by forming the middle portion of the tapered flat plate as an unconstrained portion having a width narrower than both side portions. The variation in the weight of the material at that time is absorbed, and the dimensional accuracy of the plate thickness on both sides of the tapered flat plate is improved.

〔Example〕

Hereinafter, details of the present invention will be described with reference to embodiments shown in the drawings.

1 and 2 show one embodiment of the link plate of the present invention. In these figures, reference numeral 31 indicates a plate body, and through holes are formed on both sides of the plate body 31. 32 are formed.

Further, in this embodiment, the plate thickness of the intermediate portion 33 of the plate body 31 is smaller than the plate thickness of the both side portions 35.

The link plate configured as described above is formed by processing the cylindrical rod member 37 as shown in FIG. 3 by the processing procedure described below.

That is, in this embodiment, first, as shown in FIGS. 4 to 6, the bar material 37 is processed into a flat plate shape by the preforming step to form the flat plate 39.

This preforming step is performed in order to prevent the occurrence of end face defects as shown in FIG. 18 in the upsetting step described later.

Depending on the relationship between the length and width of the product and the diameter and length of the rod 37 with respect to the thickness, the end face defect does not occur, so this preforming step can be omitted, and as described in claim 3. In the upsetting process, the bar 37 can be formed into a plate shape at the same time.

Next, as shown in FIGS. 7 and 8, the amount side portion 35 of the flat plate 39 processed in the preforming step is processed by the upsetting step so that the plate thickness of the intermediate portion 33 toward the intermediate portion 33 is, for example, ,
A tapered surface 41 is formed so as to be smaller than the plate thickness of both side portions 35 after the molding process by about 0.2 to 0.5 mm.

This upsetting step is performed to balance the volume of the molded portion and the non-molded portion during molding in the molding step described later.

Further, the reason why the plate thickness of the intermediate portion 33 is smaller than that of the both side portions 35 is that only the both side portions 35 are formed in the forming step described later.

Next, as shown in FIGS. 9 and 10, the tapered surface 41 of the tapered flat plate 43 processed in the upsetting step is molded in the molding step to form a flat surface having the same plate thickness.

This forming step is performed by a press machine including a die 45 and a punch 47 as shown in FIG. 11, but as shown in the figure, only both side portions 35 of the tapered flat plate 43 are partially formed. Therefore, the molding load can be significantly reduced as compared with the conventional case.

In addition, this molding, as shown in Figure 12, the plate body
This is done by making the intermediate part 33 of 49 a narrow non-restraining part, in which the weight variation of the material 37 at the time of molding is absorbed, and the plate thickness dimension of both side parts 35 of the plate body 49 is stable. Be converted.

In this case, the width A of the intermediate portion 33 of the plate body 49 is
Therefore, in order to regulate the width A of the intermediate portion 33, as shown in FIG. 13, convex portions 51 projecting inward are provided on both sides of the intermediate portion 33. The width A can be regulated. Also in this case, the spaces for absorbing the weight variation of the material 37 are provided on both sides of the convex portion 51.
It is necessary to provide 53.

Next, as shown in FIG. 14, through-holes 32 are formed in both sides of the plate body 49 molded in the molding process by the piercing process, and the final product of the link plate is manufactured.

In the link plate configured as described above, the plate thickness of the intermediate portion 33 of the plate body 31 is set to be smaller than the plate thickness of both side portions 35.
It is possible to process by molding only both side parts 35 of 31, and it is possible to process with a comparatively small molding load, and it is possible to greatly reduce the variation in the plate thickness on both sides of the link plate compared to the past. Become.

Further, in the link plate manufacturing method described above, after the material 37 is processed into a flat plate shape by the preform process,
By the upsetting step, tapered surfaces 41 that are inclined toward the intermediate section 33 such that the plate thickness of the intermediate section 33 is small are formed on both sides of the flat plate 39. Tapered surface 41 is formed, and both sides of plate body 49
Since 35 is a flat surface with the same plate thickness, it is possible to process with a comparatively small molding load, and it is possible to significantly reduce the plate thickness variation on both sides 35 of the link plate compared to the past. Become.

In the embodiment described above, by utilizing the sag of the corner portion formed on the tapered flat plate 43 in the upsetting step, by forming a chamfer or an R portion in the corner portion of the plate body 49 during the molding step, Burr-free molding is easily possible.

It should be noted that in the above-described embodiment, an example in which the molding is performed in a state in which the outer periphery of the plate body 49 is restrained in the molding step has been described, but the present invention is not limited to this embodiment, and for example, upset By reliably setting the volume balance and shape of both sides 35 of the tapered flat plate 43 during the process, it is possible to perform molding with the entire circumference of the plate body 49 unconstrained.

Further, in the embodiment described above, the example in which the through hole 32 is formed in the plate body 49 in the piercing process is described.
The present invention is not limited to such embodiments, and it goes without saying that, for example, piercing can be simultaneously performed in the molding step.

Further, in the above-described embodiment, the example in which the tapered surface 41 is formed only on one side of the flat plate 39 is described, but the present invention is not limited to such an embodiment, and the tapered surface is formed on both side surfaces of the flat plate 39. Of course, it may be formed.

〔The invention's effect〕

As described above, in the method for manufacturing the link plate according to the first aspect, after the material is processed into a flat plate shape by the preforming step, the upset step is performed on both side portions of the flat plate to form the intermediate portion toward the intermediate portion. A tapered surface is formed so as to be inclined so that the plate thickness becomes small, and thereafter, a tapered surface of the tapered flat plate is formed by a molding process, so that both sides of the plate body have flat surfaces of equal plate thickness. Therefore, it is possible to perform processing with a comparatively small forming load, and it is possible to significantly reduce variations in plate thickness on both sides of the link plate as compared with the conventional case.

Further, in the method of manufacturing the link plate according to the second aspect, the preform step is omitted in the first aspect, so that there is an advantage that the manufacturing cost can be reduced.

Further, in the method for manufacturing the link plate according to claim 3, in the method according to claim 1 or 2, the forming step is performed by forming the middle portion of the tapered flat plate into an unrestrained portion having a width narrower than both side portions. In this non-restraint part, the weight variation of the material at the time of molding is absorbed, and the dimensional accuracy of the plate thickness on both sides of the tapered flat plate is improved.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of the link plate of the present invention. FIG. 2 is a top view of FIG. FIG. 3 is a perspective view showing a bar. 4 to 6 are a top view and a side view showing the material shape after the preforming process. 7 and 8 are a top view and a side view showing the material shape after the upsetting process. 9 and 10 are a top view and a side view showing the material shape after the molding process. FIG. 11 is a vertical sectional view showing a press machine used in the molding process. 12 and 13 are explanatory views showing details of the molding step. FIG. 14 is a top view showing the material shape after the piercing process. FIG. 15 is a plan view showing a conventional example. 16 to 18 are explanatory views showing a method of manufacturing a link plate from a rod. [Explanation of symbols of main parts] 31 …… Plate body 32 …… Through hole 33 …… Intermediate part 37 …… Material 39 …… Plate 41 …… Tapered surface 43 …… Tapered flat plate.

Claims (3)

[Claims] 1. A preform process for processing a bar into a flat plate shape, and both side portions of the flat plate processed by this preform process are inclined so that the plate thickness of the intermediate part becomes smaller toward the intermediate part. A link plate manufacturing method comprising: an upset step of forming a tapered surface; and a forming step of forming the tapered surface of the tapered flat plate processed in the upset step to form a flat surface having an equal plate thickness. 2. An upsetting step in which a bar material is processed into a flat plate shape, and tapered surfaces which are inclined toward both sides of the bar material such that the plate thickness of the intermediate portion is reduced, and the upsetting step. And a step of forming the tapered surface of the tapered flat plate processed in step 1 to form a flat surface having an equal plate thickness. 3. The forming step is carried out by forming an intermediate portion of the tapered flat plate into an unrestrained portion having a width narrower than that of both side portions. The method for manufacturing a link plate according to claim 1 or 2, wherein the dimensional accuracy of the plate thickness on both sides of the flat plate is improved.