JP3331499B2 - Bush processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing a bush constituting a roller chain.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional general roller chain. As shown in FIG.
It consists of an inner plate (b), pin (c), bush (d), and roller (e). Both inner plates (b) and (b) are press-fit into the hole and connected, and the bush A roller (e) is rotatably fitted in (d). A pin (c) is inserted into the hole of the bush (d), and an outer plate (a)
(A) is fitted.

Incidentally, the bush (d) is a cylindrical body having a through hole, and the bush (d) is formed by bending a thin band material at a predetermined length and cutting a thin plate. There are punched, deep drawn, and punched bottoms, and further, columnar blocks are extruded and then punched out. Because each has its strengths and weaknesses,
A bush suitable for a given roller chain is used.

The bush to which the present invention is applied is formed by cold forging (forming) using a cylindrical body as a material. FIG. 7 shows a conventional method for forming tapered surfaces at both ends of an inner peripheral surface of the bush. . In a state set in a die with an inner diameter slightly larger than the outer diameter of the bush, it is compressed by being sandwiched between the lower punch (f) and the upper punch (g), and tapered surfaces (h) are formed at both ends of the inner circumference Is done.

By making both ends of the inner peripheral surface of the bush of the roller chain tapered in this way, when pressed into the inner plate hole, the hole becomes a straight hole. As a result, the straightness of the chain is improved and the elongation of the chain is reduced. Can be suppressed. As the prior art in which both ends of the bush inner circumference are tapered, a "chain bush" according to Japanese Utility Model Laid-Open No. 55-34579 and a "chain" related to Japanese Utility Model Laid-Open No. 55-36740 are known.

In order to provide a tapered surface on the bush, a method is used in which the formed bush is set on a die and punches are pressed from both sides. On this occasion,
In the case of performing processing while suppressing the outer diameter of both ends from increasing, wrinkles (ri) as shown in FIG. 8 occur near the tip of the punch, and the wrinkles (ri) deteriorate the straightness of the roller chain. At the same time, the sliding contact with the pin is affected, and the chain becomes rigid.

Further, as shown in FIG. 9, when the inner diameter of the forming die is made larger than the outer diameter of the bush and the outer diameters at both ends are enlarged to form a drum shape, when the bush is pressed into the hole of the inner plate. Causes galling. If both ends having the larger outer diameter are press-fitted into the holes of the inner plate, as shown in FIG. 10, the outer diameters of both ends of the bush are compressed and become drum-shaped, and the central portion expands, resulting in a chain. Is less straight. Of course, the pin is worn by one side,
As a result, chain growth is promoted.

[0008]

As described above, the conventional bushing has the above-mentioned problems. The problems to be solved by the present invention are these problems, without forming wrinkles on the inner peripheral surface and expanding the outer diameter of both ends to make a drum shape, resulting in a high straightness of the chain. Provided is a method for processing a bush that constitutes a roller chain having small elongation.

[0009]

The roller chain bush to which the present invention is directed has a taper at both ends of the inner peripheral surface. When this taper processing is performed, wrinkles remain on the inner peripheral surface. This is a processing method in which the outer diameters of both ends are not enlarged so as not to form a drum shape. Therefore, a cylindrical material having a predetermined outer diameter and height is set in a die hole, punches are punched in from both ends to form a concave portion, and in the next step, the punch is further compressed by both punches to form a deeper concave portion.

[0010] The bottom remaining between the two concave portions is punched to form a cylindrical body. When the bottom is punched, a taper is simultaneously formed on the inner peripheral surface on one side. On the opposite side, the direction of the bush is reversed, and then the punch is pushed in to taper. Also, after the bottom is punched out and made into a cylindrical body, tapering may be performed on each side, and in any case, burnishing is applied so that no wrinkles remain on the inner peripheral surface and it does not become a drum shape. You.

The punch has a burnishing portion having a larger outer diameter, for example, a spherical portion, at the tip so that burnishing can be performed. Alternatively, it is also possible to provide a burnishing portion on the bottom punch and perform burnishing when removing the punch from the bush hole.
Of course, the taper processing is performed at the same time as the bottom cutting. After that, the taper processing on the opposite side can be performed after inversion. However, in this case, a taper punch is press-fitted so that the opposite tapered surface already processed by the taper processing does not collapse. Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

[0012]

FIG. 1 shows an embodiment of a bushing process according to the present invention, in which (a) is a cylindrical material, which is obtained by cutting a wire having a predetermined thickness into a predetermined length. The upper and lower end faces are compressed to correct the distorted cylindrical shape. (B) shows that this material 1 is set in a die hole,
This is a case in which Here, it is also possible to press the punch to form the shallow recesses 2 and 3 in advance without forming the recesses 2 and 3 having a predetermined depth in one step, and then process the step (b). .

The material obtained by cutting the wire rod in this manner is formed sequentially, but is formed by using a plurality of dies fixed to a mold and respective punches. by the way,
By pressing the punch from above and below with the die set in the holes, the recesses 2 and 3 are formed, but the bottom 4 remains between the two recesses, and this bottom 4 is punched in the next step.

(C) is a case where the bottom 4 is punched out,
In the present invention, a tapered surface 6 is formed on one side (lower side) of the inner peripheral surface 5 simultaneously with the punching of the bottom 4. Opposite side (upper)
The inner peripheral surface 5 is a straight surface. Then, when the cylindrical body is inverted, a tapered surface 6 is formed also on the inner peripheral surface 5 on the opposite side. That is, both ends of the inner peripheral surface 5 are tapered surfaces 6,
A bush consisting of 6 is completed.

FIG. 2 shows the step (c) shown in FIG.
(D) shows a specific processing method. The cylindrical body having the bottom 4 formed in the step (b) of FIG. 1 is set in a die hole, and the bottom is formed by a punch 7 projecting from below. 4 is punched out. Since the punch 7 has the tapered portion 8, the tapered surface 6 is machined at the lower end of the inner peripheral surface 5 if the tapered portion 8 fits into the lower part of the hole 9. FIG. 4D shows a case where the direction of the cylindrical body is reversed to machine the tapered surface 6 also on the opposite side, and another punch 10 is similarly pushed from below.

The punch 10 is also formed with a tapered portion 8. If the punch 10 is pushed into the hole 9, a tapered surface 6 is formed on the inner peripheral surface 5. The punch 10 has a sphere 11 at its tip, and even if wrinkles as shown in FIG. 8 are generated at the boundary of the tapered surface 6 formed by driving the tapered portion 8, the sphere 11 The wrinkles disappear when the is pulled out of the hole. That is, the holes are burnished.

FIG. 3 shows another processing method of steps (c) and (d). In this case, the taper surface 6 is formed at the time when the bottom 4 is punched in the previous step to form a cylindrical body.
(C) shows the case where the tapered surface 6 is machined on one side, and (d) shows the case where the punch is inserted and the tapered surface 6 is formed on the inner peripheral surface when the direction is reversed. The punch 10 is the same as that used in FIG. 2D, and has a spherical body 11 at the tip and the tapered portion 8. Then, when the punch 10 is taken in and out of the hole, the inner peripheral surface 5 is burnished.

FIG. 4 shows still another specific processing of the steps (c) and (d). In (c), the punch 12 is pushed into the hole 9 to punch out the bottom 4 and simultaneously form the tapered surface 6 at the lower end of the inner peripheral surface 5. And this punch 12
Has a spherical portion 13 at the front end thereof, which can remove burrs generated when punching the bottom 4 and wrinkles generated by forming the tapered surface 6. That is, when the punch 12 is pulled out from the hole 9, these burrs and wrinkles are removed.

That is, the inner peripheral surface 5 is burnished.
Will be beautiful. In this manner, the tapered surface 6 is formed on one side of the inner peripheral surface 5 and is inverted, and the punch 14 enters the hole from above and the punch 15 enters from below, as shown in FIG. Inner peripheral surface 5 at lower end by punch 15
A tapered surface 6 is formed. At this time, the upper punch 14
Is fitted in the hole 9 so that the tapered surface 6 formed in the step (c) is not deformed or wrinkled.

FIG. 5 shows a case in which the bush manufactured as described above is incorporated in a roller chain. The bush hole is compressed inward by fitting the tip of the bush into the hole of the inner plate, as shown in FIG. It becomes a straight hole, and the rigidity of the chain is eliminated, and the extension of the chain can be suppressed by eliminating one contact with the pin.

As described above, the bushing method of the present invention is for forming a tapered surface on the inner peripheral surface of the bushing hole as a part of the cold forging step, and has the following effects.

[0022]

According to the bushing process of the present invention, tapered surfaces can be formed at both ends of the inner peripheral surface without increasing the number of steps. The processing method of the present invention is such that a taper surface is formed on both ends of the inner peripheral surface of the bush hole without changing a shape of the entire bush by processing a taper surface on both ends and burnishing the inner peripheral surface. No wrinkles remain.
In addition, the both ends do not bend outward and become a drum shape. Therefore, if a roller chain is assembled using this bush, the straightness of the chain will be high, and the rigidity will not occur.In addition, the one-side contact between the inner peripheral surface of the bush and the pin will be eliminated, and wear will be suppressed. Elongation decreases.

[Brief description of the drawings]

FIG. 1 illustrates a bushing process according to the present invention.

FIG. 2 shows the processing of steps (c) and (d) in FIG.

FIG. 3 shows the processing of steps (c) and (d) in FIG.

FIG. 4 shows the processing of steps (c) and (d) in FIG.

FIG. 5 is a roller chain to which a bush manufactured by the method of the present invention is assembled.

FIG. 6 is a general roller chain.

FIG. 7 shows a conventional method of forming tapered surfaces at both ends of an inner peripheral surface of a bush.

FIG. 8 shows a conventional bush having a tapered surface.

FIG. 9 shows a conventional bush having a tapered surface.

FIG. 10 is a roller chain incorporating a bush having a tapered surface shown in FIG. 9;

[Description of Signs] 1 material 2 concave portion 3 concave portion 4 bottom 5 inner peripheral surface 6 tapered surface 7 punch 8 tapered portion 9 hole 10 punch 11 sphere 12 punch 13 spherical portion 14 punch 15 punch

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B23P 13/00 B21D 28/24 B21L 9/00 B24B 39/02 F16G 13/06

Claims (3)

(57) [Claims] In a method of processing a bush of a roller chain having tapered surfaces at both ends of an inner peripheral surface, a columnar body obtained by cutting a wire having a predetermined thickness is used as a material, and this material is set in a die and vertically moved. A punch is pressed against the end surface to form a recess, and the bottom left between the two recesses is punched out with the tip of the punch, and the tapered portion formed on the punch is pressed into the hole to form one end of the inner peripheral surface of the hole. Forms a tapered surface, further presses a punch having a spherical body at the tip and a tapered portion from the opposite side to form a tapered surface at the other end of the inner peripheral surface and burnish the inner peripheral surface A bushing processing method characterized by processing. 2. A method of processing a bush of a roller chain having a tapered surface at both ends of an inner peripheral surface, wherein a cylindrical body obtained by cutting a wire rod having a predetermined thickness is used as a material, and the material is set on a die and vertically moved. Pressing a punch on the end surface to form a recess, punching the bottom left between both recesses at the punch tip, penetrating the hole, pushing a punch having a spherical body at the tip and having a tapered part into the hole Forming a tapered surface at one end of the inner peripheral surface of the hole by pressing in from the opposite side to form a tapered surface at the other end of the inner peripheral surface and burnishing the inner peripheral surface. Method. 3. A method of processing a bush of a roller chain having tapered surfaces at both ends of an inner peripheral surface, wherein a cylindrical body obtained by cutting a wire having a predetermined thickness is used as a material, and the material is set in a die and vertically A punch is pressed against the end surface to form a recess, and the bottom left between the two recesses is punched out with the tip of the punch, and the tapered portion formed on the punch is pressed into the hole to form one end of the inner peripheral surface of the hole. Molds the tapered surface, and when pulling out the punch from the hole, burnishes the inner peripheral surface with the spherical part of the tip of the punch, further pushes both punches with a tapered part at the tip from both sides, and A bushing processing method, wherein a tapered surface is formed at the other end.