JP2002028749A - Link plate finishing method, and link plate finished by the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the fatigue strength of a link plate for a silent chain by preventing generation of micro-cracks. SOLUTION: In the link plate 2, the shaving (step (c)) of each inner flank surface 2a and a crotch part 5 is simultaneously performed after punching the contour of a tooth part 2 (step (b)). The part from the inner flank surface 2a to the crotch part 5 can be formed smooth with uniform surface roughness, and as a result, generation of micro-cracks can be prevented, the fatigue strength can be improved, and the structure of the entire die including a shaving die can be simplified. It can cope with a liner-type tensioner by forming a flat surface on a tip part 2c of the tooth part 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of finishing a link plate for a silent chain having a pair of teeth and a pin hole, and a link plate for a silent chain processed by the method.

[0002]

2. Description of the Related Art In general, a silent chain is formed by stacking a number of link plates each having a pair of teeth and a pin hole in a thickness direction and a longitudinal direction and connecting each link by a connecting pin inserted into the pin hole. It is constituted by pivotally connecting the plates.

As a typical processing step for manufacturing a link plate, first, as shown in FIG. 6A, a pin hole Pa is formed by punching a band-shaped blank material B with a punch. Then, as shown in FIG.
The contour of the link plate L is punched out using another punch.

As shown in FIG. 7, the outer peripheral surface of the conventional link plate L punched in this way has a shear plane a having a length (shear plane length) ha of 20 times the plate thickness t of the link plate. It is only about 30%, and the fact is that a fractured surface b is formed in most of the area of the outer peripheral surface.

[0005] Therefore, during operation of the silent chain in which such link plates are combined, the sprocket meshing surface of the link plate may cause one-sided contact to cause uneven wear, or stress concentration may occur on the sprocket meshing surface. There was a problem.

Accordingly, Japanese Unexamined Patent Publication No. 9-217796 (hereinafter referred to as a gazette) and Japanese Unexamined Patent Publication No. 2000-35088
As shown in Japanese Patent Application Publication (hereinafter referred to as "publication"), there has been proposed one in which a shaving process is performed on a sprocket meshing surface of a link plate and an inner surface of a pin hole.

FIG. 4 shows a link plate having a sprocket meshing surface subjected to shaving by the method disclosed in each of the above publications. In the figure, a link plate 100 has a pair of tooth portions 101 and a pin hole 102, and each tooth portion 101 is constituted by an inner flank surface 103 and an outer flank surface 104, respectively. 103 is the crotch part 10
5 are connected. Then, each inner flank surface 103 and outer flank surface 104 which are sprocket meshing surfaces
Is formed with a shaving surface S.

However, in this case, shaving is performed only on the sprocket meshing surface of the link plate whose outer shape has been punched (see column 4, lines 11 to 13 of the publication and column 4 of the publication). See lines 2-4).

For this reason, as shown in the enlarged view of FIG. 5, the inner flank surface 103 is a smooth surface finished by shaving, but the crotch portion 105
The tooth tip 106 is a rough surface that has only been punched, and the surface roughness of the shaved surface S of the inner flank 103 and the crotch portion 105 and the tooth tip 106
Is significantly different from the surface roughness. In FIG. 5, the surface roughness of the crotch portion 105 and the tooth tip portion 106 is slightly exaggerated.

[0010] The inventors of the present application conducted various fatigue tests on the silent chain formed by combining such link plates and examined the fatigue strength of the link plates. The occurrence of microcracks was found at the location of the symbol f in FIG. 5, which is the boundary between the surface S and the crotch portion 105.

This is presumed to be due to the occurrence of stress concentration at a point f where the surface roughness changes abruptly from a microscopic point of view. In addition, such a microcrack may be a starting point of fatigue during operation of the silent chain, and may cause fatigue fracture therefrom. Therefore, it is desirable to suppress the occurrence thereof. Further, the portion indicated by the symbol f is a portion where the distance between the inner flank surface 103 and the pin hole 102 is the smallest, and also a weakest portion on the strength of the link plate 100. It is necessary to prevent microcracks from occurring.

The present invention has been made in view of such a conventional situation, and an object of the present invention is to provide a finishing method capable of preventing occurrence of microcracks and improving fatigue strength in a link plate for a silent chain. And a link plate for a silent chain machined by such a finishing method.
Another object of the present invention is to provide a finishing method capable of simplifying the entire structure of a die including a shaving die, and to provide a link plate for a silent chain processed by such a finishing method. It is in. Still another object of the present invention is to provide a method of finishing a link plate of a silent chain which can be applied to a tensioner of a lining type, so that the entire structure of a mold including a shaving mold can be simplified, and such a method is provided. An object of the present invention is to provide a link plate for a silent chain processed by a finishing method.

[0013]

According to a first aspect of the present invention, there is provided a method of finishing a link plate, comprising a pair of pin holes for inserting a connecting pin, and a pair of inner flank surfaces and outer flank surfaces. A method of finishing a link plate for a silent chain having a tooth portion and a crotch portion connecting each of the inner flank surfaces, wherein shaving is simultaneously performed on each of the inner flank surfaces and the crotch portion. It is characterized by:

[0014] The "shaving process" as used herein means that a punched surface of a blank is cut by using a shaving die slightly larger than a punched portion formed by punching a blank with a punch. Rough surface and droop generated on the punched surface during punching by
A processing method that improves the surface roughness of the punched surface.

A second aspect of the present invention is characterized in that, in the first aspect, the shaving process is performed after an outer shape punching process of the tooth portion.

[0016] Claim 3 is based on claim 1 or 2,
A flat surface extending substantially parallel to a pitch line passing through the center line of each of the pin holes is formed at the tip of the tooth portion, and when shaving the inner flank surface and the crotch portion, the flat surface is formed. It is characterized in that the surfaces are simultaneously shaved.

A fourth aspect of the present invention is characterized in that, in any one of the first to third aspects, at the time of the shaving, the outer flank surface is simultaneously subjected to shaving.

According to a fifth aspect of the present invention, there is provided a link plate for a silent chain, wherein a pair of pin holes for inserting a connecting pin, a pair of tooth portions each including an inner flank surface and an outer flank surface, A crotch portion for connecting the inner flank surfaces, and the inner flank surfaces and the crotch portions are simultaneously shaved.

According to a sixth aspect of the present invention, in the fifth aspect, the shaving is performed after the outer shape punching of the tooth portion.

According to a seventh aspect of the present invention, in the fifth or sixth aspect, a flat surface extending substantially parallel to a pitch line passing through a center line of each of the pin holes is formed at a tip of the tooth portion. When the shaving process is performed on each of the inner flank surfaces and the crotch portion, the flat surface is simultaneously shaved.

According to an eighth aspect of the present invention, in any one of the fifth to seventh aspects, at the time of the shaving processing, the outer flank face is simultaneously subjected to shaving processing.

A ninth aspect of the present invention is characterized in that, in the fifth aspect, the pin hole is also subjected to shaving processing.

In the first and fifth aspects of the present invention, shaving is applied to each inner flank surface and crotch portion of the link plate. For this reason, all shaving-processed surfaces are formed from each inner flank surface to the crotch portion, and the surface roughness is uniformly formed. In addition, shaving is performed on these portions at the same time, so that micro steps are less likely to occur. As a result, it is possible to prevent the occurrence of microcracks in the portion from each inner flank to the crotch portion, and as a result, it is possible to improve the fatigue strength.

According to the second and sixth aspects of the present invention, the shaving process is performed after the outer shape punching process of the entire tooth portion of the link plate. Thereby, the structure of the entire die including both the outer shape punching die and the shaving die can be simplified. On the other hand, instead of punching out the outer shape of the entire tooth portion at once, first punch out the outer shape of the inner flank surface and the crotch portion, and then perform shaving processing of these portions. However, in this case, the outer shape punching process of the inner flank surface and the crotch portion is additionally required, and the structure of the entire mold is complicated.

According to the third and seventh aspects of the present invention, a flat surface extending substantially parallel to the pitch line passing through the center line of each pin hole is formed at the tip of the tooth portion of the link plate. The flat surface is simultaneously subjected to shaving at the time of shaving of each inner flank surface and crotch portion.

In this case, the flat surface formed on the tooth tip of each link plate is a lining type tensioner on which tension acts from the inner peripheral surface side of the silent chain, that is, from the tooth tip side of the link plate. Because it can be on the contact surface of
It is possible to easily cope with such a liner type tensioner.

Also, in this case, since a portion from the tip of the tooth portion to the crotch portion through the inner flank surface is simultaneously shaved, an integrated shaving die corresponding to these portions is used. As a result, the structure of the shaving mold can be simplified, and the precision of the mold can be easily managed. On the other hand, in the case where only the inner flank surface of the tooth portion is shaved as in the related art, the structure of the mold is complicated.

According to the fourth and eighth aspects of the present invention, when shaving the inner flank surface and the crotch portion,
The outer flanks are also shaved. In this case, a more integrated shaving mold can be used, whereby the structure of the shaving mold can be further simplified, and the management of the precision of the mold is further facilitated.

According to the ninth aspect of the present invention, the pin hole is also subjected to shaving. In this case, the wear of the pin can be reduced, and the life of the pin can be improved.

[0030]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 3 are views for explaining an embodiment of the present invention. FIG. 1 is a process diagram for explaining an example of a link plate processing process, and FIG. 2 is a process diagram of FIG. FIG. 3 is a partially enlarged view of the link plate of FIG. 2.

First, the steps of processing the link plate according to the present embodiment will be described with reference to FIG. As shown in the figure, while the blank material B is transported in the direction of the arrow and sequentially moved to the processing position, first, in the first step (a),
By punching out the hatched portion S1, a hole Pa 'for forming a pair of pin holes of the link plate is formed.
Note that the hatched portions in FIG. 1 indicate portions that become scraps.

Next, in the second step (b), a substantially W-shape to form the inner flank surface, outer flank surface, crotch portion and tooth tip portion of the link plate by punching out the hatched portion S2. Is formed. Here, a case where a flat surface is formed on the tooth tip is taken as an example.

Next, in a third step (c), shaving is performed on the hole Pa 'and the face L1' using a shaving mold. As a result, the inner peripheral surface of the hole Pa 'is cut to form a shaving hole Pa slightly larger in inner diameter than the hole Pa'. The surface L1 'is cut to form a shaved surface L1.

[0034] The "shaving process" here means that the punched surface of the blank is cut by using a shaving die slightly larger than a punched portion formed by punching the blank with a punch. Rough surface and droop generated on the punched surface during punching by
A processing method that improves the surface roughness of the punched surface.

After the shaving process, the link plate is taken out from the blank material B by punching out the link plate back surface indicated by the broken line in FIG. The punching of the link plate back may be performed in any of the first and second steps (a) and (b) while leaving a part of the link plate back. In this case, in the third step (c), the shaving of the back surface of the link plate may be performed together with the shaving of the surface L1 '.

FIG. 2 shows the link plate taken out of the blank material B. In FIG.
Has a pair of teeth 2 and a pin hole 10,
Each tooth portion 2 includes an inner flank surface 2a and an outer flank surface 2b, and adjacent inner flank surfaces 2a are connected by a crotch portion 5.

As shown in FIG. 3, which is an enlarged view of FIG. 2, the inner flank surface 2a, crotch portion 5, and tooth tip 2c of the link plate 1 are simultaneously shaved in the third step (c). Processing is performed, and therefore, each of them is formed of a smooth surface and has a uniform surface roughness. In addition, since these parts are simultaneously subjected to shaving processing, there is no micro level difference (refer to the part indicated by the symbol f which is the weakest part of the link plate in FIG. 3). This prevents the occurrence of microcracks in the portion from each inner flank surface 2a to the crotch portion 5, and as a result, the fatigue strength is improved.

Further, in this case, as described above, the shaving process is performed after the outer shape punching process of the entire tooth portion 2 of the link plate 1. Thereby, the structure of the entire die including both the outer shape punching die and the shaving die can be simplified. On the other hand, the outer shape of the entire tooth portion is 1
Instead of punching in a round, first punch out the outer shape of the inner flank face and crotch, then shaving these parts, and then punch out the outer shape of the entire tooth part. In this case, the number of steps of punching the outer shape of the inner flank surface and the crotch portion is increased, and the structure of the entire mold is complicated.

Further, a flat surface extending substantially parallel to a pitch line m (FIG. 2) passing through the center line of each pin hole 10 is formed on the tooth tip 2c of the tooth portion 2 of the link plate 1.
This flat surface is subjected to shaving at the same time as the shaving of each inner flank 2a and crotch portion 5.

In this case, the flat surface formed on the tooth tip 2c of each link plate 1 is formed from the inner peripheral surface of the silent chain, that is, the lining on which the tension acts from the tooth tip of the link plate 1. Since it can be used as a contact surface of a mold tensioner, it is possible to easily cope with such a liner-type tensioner.

Also, in this case, the portion from the outer flank surface 2b of the tooth portion 2 to the crotch portion 5 through the tooth tip portion 2c and the inner flank surface 2a is simultaneously subjected to shaving processing. The integrated shaving mold described above can be used, whereby the structure of the shaving mold can be simplified, and the accuracy of the mold can be easily managed. On the other hand, when only the inner flank surface or the outer flank surface of the tooth portion is shaved as in the related art, the structure of the mold is complicated.

[ Other Application Examples ] In the above embodiment,
Although a link plate having a circular pin hole has been described as an example, the present invention can be similarly applied to a link plate in which a deformed hole for a rocker joint is formed.

[0043]

As described above, according to the present invention, the shaving process is simultaneously applied to each inner flank surface and crotch portion of the link plate, so that the occurrence of microcracks can be prevented and the fatigue strength can be improved. There is. Further, according to the present invention, since the shaving process is performed after the outer shape punching process of the tooth portion, there is an effect that the entire structure of the mold including the shaving mold can be simplified.
Further, according to the present invention, the flat surface formed on the tooth tip of the tooth portion is subjected to shaving at the same time as the shaving process of each inner flank surface and crotch portion, so that it is compatible with a lining type tensioner. This makes it possible to simplify the structure of the entire mold including the shaving mold.

[Brief description of the drawings]

FIG. 1 is a process chart for explaining a link plate processing process according to an embodiment of the present invention.

FIG. 2 is an enlarged front view of a link plate processed in the processing step of FIG. 1;

FIG. 3 is a partially enlarged view of the link plate of FIG. 2;

FIG. 4 is an enlarged front view of a conventional link plate.

FIG. 5 is a partially enlarged view of FIG. 4;

FIG. 6 is a process chart for explaining a conventional link plate processing process.

FIG. 7 is an enlarged cross-sectional view of an outer peripheral surface of a conventional link plate.

[Explanation of symbols]

 1: Link plate 2: Tooth portion 5: Crotch portion 2a: Inner flank surface 2b: Outer flank surface 2c: Tooth tip portion 10: Pin hole m: Pitch line

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[Procedure amendment]

[Submission date] July 14, 2000 (2007.1.
4)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 3

FIG. 2

FIG. 4

FIG. 5

FIG. 6

FIG. 7

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Ryoji Tsujii 1300-50 Yawata-guchi Ichino, Nabari-shi, Mie Borg Warner Automotive Co., Ltd. (72) Inventor Ken-ichi Matsuura 1300 Yachiman-guchi Ichino, Yawata, Nabari-shi, Mie Prefecture No. 50 Borg-Warner Automotive Co., Ltd. (72) Inventor Akio Matsuda 1300 No. 50, Borg-Warner Automotive Co., Ltd. F-term (reference) 3C025 DD02 DD07

Claims (9)

[Claims] 1. A silent having a pair of pin holes for inserting a connecting pin, a pair of teeth each including an inner flank surface and an outer flank surface, and a crotch portion connecting the respective inner flank surfaces. A method of finishing a link plate for a silent chain, wherein shaving is simultaneously performed on each of the inner flank surfaces and the crotch portion. 2. The method of finishing a link plate for a silent chain according to claim 1, wherein the shaving process is performed after an outer shape punching process of the tooth portion. 3. The tooth tip of the tooth portion according to claim 1 or 2, wherein a flat surface extending substantially parallel to a pitch line passing through a center line of each of the pin holes is formed on a tip of the tooth portion.
A method of finishing a link plate for a silent chain, wherein the flat surface is simultaneously subjected to shaving at the time of the shaving on each of the inner flank surfaces and the crotch portion. 4. The finishing process of a link plate for a silent chain according to claim 1, wherein the shaving process is performed on the outer flank surface at the same time. Method. 5. A link plate for a silent chain, comprising: a pair of pin holes for inserting a connecting pin; a pair of tooth portions each including an inner flank surface and an outer flank surface; And a crotch portion connecting the inner flanks and the crotch portion are simultaneously shaved. 6. The link plate for a silent chain according to claim 5, wherein the shaving process is performed after an outer shape punching process of the tooth portion. 7. The tooth tip of the tooth portion according to claim 5, wherein a flat surface extending substantially parallel to a pitch line passing through a center line of each of the pin holes is formed on a tip portion of the tooth portion,
A link plate for a silent chain, wherein the flat surface is subjected to shaving at the same time as the shaving process on each of the inner flank surfaces and the crotch portion. 8. The link plate for a silent chain according to claim 5, wherein at the time of the shaving processing, the outer flank face is simultaneously subjected to shaving processing. 9. The link plate for a silent chain according to claim 5, wherein the pin hole is also subjected to shaving.