JPH0813399B2 - Forged stud link chain, its manufacturing method and device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stud link chain which is lighter in weight than conventional products and which increases tensile shear stress and service life, a method of manufacturing the same and a manufacturing apparatus thereof.

[0002]

2. Description of the Related Art Conventionally, in a chain used in a ship lifting machine, a cargo handling machine, etc., in order to increase tensile shear stress in the longitudinal direction or to prevent entanglement of links, the middle portion of the O-shaped link 3 is A generally θ-shaped stud link 5 connected by studs 4 is generally used. In this type of chain, as shown in FIG. 5, a round bar steel material 10 is heated by an electric resistance heater to 850 to 900 ° C. After bending into a C shape and connecting via openings, both ends of the openings 31, 31 are joined by electric resistance welding, the burrs 32 of the welded parts are removed, and then the stud 4 is inserted and crimped by pressing. It is generally manufactured by being fixedly molded or, particularly, when the strength of the stud portion is required, its end portion is welded by CO2 gas arc welding.

[0003]

Therefore, in the above-mentioned conventional manufacturing method, (1) since a steel bar having a uniform cross section is bent by 180 °, the bent portion (so-called shoulder portion) has a slightly smaller diameter than the other portions. However, since the tensile stress of the chain easily acts on this portion, fatigue fracture is likely to occur from that point. In addition, (2) In the method of crimping and fixing the stud, repeated use causes deformation stress on the outer peripheral link part, and there is a risk that the stud may fall due to rust, while in the method of welding and fixing one end, the welding point is repeated. There is a drawback that the outer peripheral link portion due to use is susceptible to fatigue fracture due to deformation stress. Particularly, in a conveyor chain and a fishing chain in which the stud is pulled during driving, the stud needs to have higher strength. Further, (3) it is proposed to use a steel material which is lightweight and has excellent tensile strength, such as SUS or chrome molybdenum steel, for the traction support of the offshore structure, but there is a problem in weldability and the conventional method is used. It is difficult to do so. Furthermore, (4) As shown in FIG. 6, the chain wears due to friction at its connecting portion as indicated by the shaded portion m, so the service life is usually determined by its remaining diameter b. However, since the cross-sectional shape is uniform, it is necessary to increase the cross-sectional diameter in order to increase the service life, which is not possible due to the drawback that the chain weight increases dramatically. Therefore, in order to improve the fatigue strength of this type of link chain, the link chains according to JP-A-55-31677 and JP-A-62-3848 have been proposed. However, in any case, since a steel bar having a uniform cross-sectional area is subjected to maximum bending at 180 ° to form an O-link, when the chain is pulled in the longitudinal direction, the fatigue fracture resistance to the shear stress of the shoulder portion is drastically changed. The problem that cannot be solved remains. Therefore, the present invention focuses on the fact that the above-mentioned conventional problems depend on a processing method of bending and welding a steel bar having a uniform cross-sectional area, and is lighter in weight and has a tensile strength in the longitudinal direction. It is intended to provide a stud link chain excellent in

[0004]

SUMMARY OF THE INVENTION According to the present invention, the shoulder portion where shear stress is likely to be applied and the portion where wear loss is concentrated have a large cross-sectional area, and the other portions have tensile strength commensurate with that, thereby reducing the weight and at the same time. Although fatigue fracture resistance and service life can be improved, it is the result of earnest research that the manufacturing of a link with such a shape is impossible by conventional methods. One end of the fixed portion of the link portion 21 and the stud portion 22 is formed by die forging while the other stud link is formed by die forging into the completed stud link 1 having a substantially θ shape in which the link portion 11 and the stud portion 12 are integrally formed. To open the pair of link open ends 24, 24 and the stud open end 22.
b to form a substantially ε-shaped intermediate stud link 2, and insert the open ends 24, 24 of the intermediate stud link 2 into the respective cavities 13, 14 of the adjacent completed stud links 1, 1 for combination. The long side link portions 21B, 21B extending outward from the fixed end 22a of the stud portion 22 of the intermediate stud link 2 are bent inward at an angle of 45 °, preferably 30 ° to form a substantially θ shape, and at least the above-mentioned shape is formed. This is a method for manufacturing a forged stud link chain in which the abutting portions 25 of the open ends 24, 24 are welded and joined together.

[0005]

According to the present invention, one of the links is formed in a substantially θ shape and the other link is formed in a substantially ε shape by the die forging method. Therefore, (1) it is necessary to make the link cross-sectional shape uniform as in the conventional case. Instead, various cross-sectional shapes can be adopted.For example, the diameter of the outer peripheral link in the width direction of the short side is larger than the average diameter, and the diameter of the long side in the width direction is smaller than the average diameter. The tensile strength can be improved.

Moreover, (2) the stud can be integrally formed with the outer peripheral link portion, and the tensile strength of the stud can be improved as compared with the conventional pressure welding or welding. In particular, when a mounting hole for a member is formed on the stud or the stud is used as a drive part of the chain, the conventional method is convenient because the mounting hole is easily deformed or comes off when crimping to the outer peripheral link part. .

Further, (3) since it is forged, the strength of the material can be improved as compared with the conventional method of bending steel bars. In addition, (4) Since the link chain can be manufactured by the minimum welding that welds the open part of the approximately ε-shaped link that is bent into the approximately θ shape, the welded portion that tends to be a difficulty in strength is minimized. In addition to being able to suppress it, since there are few welded parts, it is difficult to weld and there is no problem even if links are manufactured using SCM steel material, SUS material, etc. with excellent tensile strength, and it is excellent by utilizing the physical properties of this steel type It is possible to manufacture a link chain with high fatigue strength.

Therefore, the completed stud link 1 formed by die forging and having a substantially θ shape manufactured by the method of the present invention, and 45 °, preferably 3 °, formed by die forging.
Intermediate stud link 2 that is combined with a partially opened intermediate stud link 2 having a substantially ε shape that can be formed into a substantially θ shape by bending within 0 ° and abutted by bending.
The forged stud link chain in which the abutting portions of are welded and chained can realize a novel stud link chain having light weight and super strength that could not be achieved by the conventional method.

Also in terms of manufacturing work, since it is possible to manufacture a chain of stud link chains by a minimum bending work into a substantially θ shape, the hot work required for the maximum bending work of 180 ° as in the conventional case. Since it can be manufactured by cold bending instead of working, and the welded part can be minimized, there is also an advantage that the number of man-hours in a bad environment can be reduced.

In manufacturing the forged chain, a bending process different from the conventional method is adopted, and thus a unique manufacturing apparatus is required. Therefore, as a result of earnest research, approximately θ
When bending the approximately ε-shaped intermediate stud link 2 that connects the completed stud link 1 having a shaped shape, it is necessary to clamp the approximately ε-shaped intermediate stud link 2 at its non-moving portion, so that it is clamped by the stud portion 22. The stud portion 22
Long side link portion 21 extending left and right from the fixed end 22a of the
B will be applied to B and 21B, but
For applying bending stress, the long side link portion 21
It is preferable to generate an abutting force at the open end orthogonal to the pressing direction with a linear pressing force against B and 21B, and therein the long side link portions 21B and 21B extending left and right from the fixed end 22a of the stud portion 22 are arranged inside. While pushing from the outside to the outside, the pushing force for the long side link portion 21B is received by the curved portions 21C on both sides thereof, and is pushed inward of the short side link portion 21A in accordance with this receiving operation,
It has been found that it is optimum that the open ends 24, 24 are butted against each other to form a substantially θ shape. Therefore, the present invention has
The intermediate stud link 2 having a shape is sandwiched by the stud portions 22, and the long side link portions 21B, 21B extending from the fixed end 22a of the stud portion 22 to the left and right are pushed out from the inside to the outside. A pair of curved portions 21C from the link portion 21B to the short side link portions 21A on both sides
And a pair of metal fittings 6, 6 which are in contact with each other and can swing around a rotation axis perpendicular to the plane L including the intermediate stud link 2. The pushing force to the long side link portion 21B in the vicinity of the stud fixing end 22a of No. 2 is the bending portion 21C on both sides thereof.
Is received by the first portion of the pair of metal fittings 6, 6 that abut on the open end 2 by the inward pushing operation of the short side link portion 21A of the second portion accompanying the receiving operation of the metal fittings 6, 6.
The present invention also provides a manufacturing apparatus capable of performing a bending process in which 4 and 24 are butted to each other to form a substantially θ shape.

[0011]

EXAMPLES The manufacturing method according to the present invention will be described in detail below with reference to specific examples. (Embodiment 1) FIG. 1 is a perspective view for explaining the steps of the method of the present invention. A pair of completed die forging links 1 having a substantially θ shape and a pair of die forging intermediate links 2 having a substantially ε shape. Open end 2
4, 24 are inserted into the cavities 13, 14 separated by the stud 12 of the completed link, and then the pair of open ends 24, 2
After bending so that 4 contact each other, open both ends 2
A link chain is manufactured by welding and joining 4 and 24 to form a chain.

More specifically, the completed link 1 is formed by die forging the link outer peripheral portion 11 and the stud portion 12 integrally, and has a substantially θ shape as shown in FIG. 2, and has a short side portion 11A and a long side portion 11B. Consists of. Shoulder 13 of the short side 11A
Has a horizontal elliptical shape, and the vertical minor axis corresponds to the link average diameter d, but the horizontal major axis is d + α, and α varies depending on the link average diameter, but the chain link longitudinal direction 10% to 15% of the average diameter, and a maximum of 3 so that a predetermined tensile strength can be imparted to the fatigue strength of the shoulder portion 13 and the fatigue fracture resistance of the shoulder portion 13 can be imparted.
0% or less is suitable. On the other hand, the cross-sectional shape of the long side portion 11B has a vertical elliptical shape, has a major axis in the vertical direction, and is equivalent to the link average diameter d, but has a minor axis in the horizontal direction and is shorter than the link average diameter d. d-β, which varies depending on the average link diameter, may be determined so as to obtain a strength commensurate with the increased tensile strength in the shoulder 13, and the average diameter may be reduced by about 15 to 20%. Up to 30%
The following are appropriate:

On the other hand, as shown in FIG. 3, in order to connect a plurality of completed links 1, the intermediate link 2 is formed to have the same sectional shape as that of the completed links, and the shoulder portion 2 of the short side portion 21A thereof.
3 has a horizontal elliptical cross section, a horizontal elliptical cross section, and a vertical minor axis corresponds to the link average diameter d, but a horizontal major axis is d + α, and a long side portion 21
In B, the major axis in the vertical direction corresponds to the average link diameter d, but the minor axis in the horizontal direction forms d-β. Moreover, the outer peripheral link 21
Is opened to the outside at one central portion of the long side portion 11B. The degree of opening is preferably such that the completed link 1 can be inserted through the opening, that is, the center lines C1 and C2 that bisect the C-shaped link sides on both sides form an intersection angle of 60 to 80 °.
The stud portion 22 projects from the central portion of the other long side portion 21B so as to bisect the open portion of the other central portion, and is die-forged into a generally ε shape as a whole. Further, the connecting portion of the stud portion 22 with the link outer peripheral portion 21 is formed to be slightly thicker in consideration of the reduction of the cross-sectional diameter due to the bending work at the time of connection, and the bending work of 45 ° or less, about 30 ° in the drawing, is required. Then, the open ends 24, 24 are brought into contact with each other, and the periphery of the contact portion 25 is welded to obtain the form shown in FIG. At this time, the tip of the stud portion 22 has a slight gap S with the abutment portion 25, but when a tensile force is applied in the longitudinal direction, the abutment portion 25 is formed.
It is adapted to come into contact with the side portions of the to reduce the shear stress applied to the shoulder portion 23. Of course, the tip of the stud portion 22 may be welded to the contact portion 25.

In the die-forged link having the above-mentioned shape, for example, when the average link diameter d is 19 mm, the cross-sectional shape of the shoulder 13 is 22 mm long, 19 mm short, 19 mm long and 11 mm short. As a result, the tensile strength could be improved by about 15% while achieving a weight reduction of about 15% as a whole, as compared with the chain link manufactured by the conventional method using a steel bar having a diameter of 19 mm.

(Embodiment 2) Mold forging is performed so as to form a member mounting hole in the central portion of the stud of the stud link chain, and a substantially θ-shaped completed link 1 and a substantially ε-shaped intermediate link 2 are formed. Was connected in the same manner as in Example 1 above, and a blade was attached to each link through the member attachment hole to form a chain conveyor. On the other hand, a stud with mounting holes was tried to be attached by crimping to the link chain re-chained by the conventional method, but the mounting holes of the studs were deformed by crimping from both ends. Therefore, after the link chain is manufactured, a mounting hole is drilled on the stud, but the work is difficult and mass production is impossible. Further, comparing the repeated use resistance of the integrated stud of the product of the present invention and the conventional crimping stud, the conventional crimping stud has a drawback that it is easy to fall off and is dropped off in a chain by one falling off. In contrast, such tendency is not seen in the integrated stud of the invention product.

FIG. 7 is a plan view showing an outline of an apparatus for carrying out the method of the present invention, and FIG. 8 is a sectional view taken along the line AA. As shown in the figure, the bending apparatus is composed of a pair of upper and lower clamping metal fittings 5, 5 and a pair of metal fittings 6, 6.

The holding and pushing fitting 5 is shown in FIGS. 9 and 10.
As shown in FIG. 7, a pair of truncated pyramid-shaped holding portions 51, 51 sandwiching the stud portion 22 of the substantially ε-shaped intermediate stud link 2 from the left and right with the tip portion 51a and the stud portion are arranged so as to sandwich it from the front and back. The support portion 52 includes a pair of parallel recessed guide grooves 52a, 52a having an arc-shaped cross section, which receives the long side link portions 21B, 21B extending in the left-right direction. The inclined side surface 51b of the sandwiching portion 51 has a support portion 52
Forms a space 53 to receive the curved portion 11C of the substantially θ-shaped completed link 1 connected to the intermediate stud link 2. Therefore, as shown in FIG.
The substantially ε-shaped intermediate stud link 2 is placed on the lower push fitting 5, and the upper push fitting 5 is attached to the tip portion 51a of the holding portion 51.
When they are overlapped so as to contact with each other (see FIG. 10), a pair of substantially θ-shaped completed links 1 and 1 are temporarily connected to each other to form approximately ε.
The shaped intermediate link 2 is firmly held by the pair of push fittings 5, 5.

On the push-out side of the push fitting 5, the contact fittings 6, 6 are a pair of upper and lower concave guide grooves 52, 52.
Are arranged to face both ends of the long side link portion 21.
A pair of curved portions 2 from B to both short side link portions 21A
The abutting portion 61 having a curved surface 61a that abuts on the 1C, the rotary shaft 6 perpendicular to the plane L including the intermediate stud link 2.
2 is supported so as to be rotatable around 2.

Therefore, when the pressing member 5 is pressed in the direction of the arrow from the state of FIG. 7, the holding portion 51 holds the stud portion 22 and the fixed end 22 of the stud portion 22 is held.
a long side link portion 21B extending left and right from the vicinity of a,
21B is pushed out from the inside to the outside, but the curved surfaces 6 of the pair of metal fittings 6, 6 are provided on the pair of curved portions 21C extending from the long side link portion 21B to the both short side link portions 21A.
Since 1a is in contact, the pushing force of the pushing metal fittings 5, 5 is received by the first portion of the pair of metal fittings 6, 6 that abut on the curved portions 21C on both sides thereof, and the receiving operation of the metal fittings 6, 6 As a result, the second part pushes the short side link part 21A inward because it tries to rotate in the direction of the arrow, whereby the open ends 24, 24 are butted against each other and bent into a substantially θ shape. Will be. Therefore, welding the butt portions 25 as in the above method completes the connection. The chain is manufactured by connecting the pair of substantially θ-shaped completed links 1 and 1 to the substantially ε-shaped intermediate link 2 and repeating the same operation.

[0020]

As is apparent from the above description, the stud link chain, which was conventionally manufactured by bending and welding a steel bar having a uniform cross section, is formed with a die forging link having a substantially θ shape and a substantially ε shape. Therefore, it is possible to avoid the reduction of the shear stress of the shoulder portion due to bending work, and by minimizing the welded portion, it is possible to reduce the shear stress of the welded portion and to use a steel type with excellent tensile strength. It is possible to provide a stud link chain which is lighter in weight than manufactured and has excellent fatigue fracture resistance. Therefore, it is possible to provide an anchor chain of a high-speed ship and a chain of excellent quality as a chain for towing offshore structures. Further, since the stud is formed integrally with the outer peripheral link, it can endure a large breaking strength, and is excellent as a conveyor chain or a fishing chain for engaging the stud with the drive means.

Using the same SBC material, a ship chain manufactured by the method of the present invention and a ship chain manufactured by the conventional method were subjected to a comparative test of the degree of wear using the following method of accelerating wear. . (Comparative test) Test device 1 Fixing jig equipped with 1 link is fixed to a vise, and friction rods (SBC35mmΦ x 1m are two in series, own weight 7.5kgf x 2)
A jig incorporating the above) was mounted on the bite attachment part, and the friction rod was reciprocated under certain conditions to apply friction to the inner surface of the link under test. Friction distance: 23.5 cm, friction speed: 28 times / min (one way). Test Method The diameter was measured before the test, and the wear amount was determined by removing the wear every 6 hours (every 10080 times) after the start of wear. In addition, the wear appearance was photographed each time it was removed. 32 mm
The relation with the wear amount when the 10% wear amount of the diameter (nominal) link is set as the limit value is shown. Test Results The measured diameter b, the wear amount mm, and the wear rate m / a shown in FIG. 6 with respect to the total number of times of friction between the product of the present invention and the conventional product were measured. The results are shown in Table 1 below. The amount of wear up to 10,000 times was small, and it seems that work was required to become familiar with the friction rod and the friction surface. The amount of wear was smaller in the product of the present invention than in the conventional product at all stages (see FIG. 11). As for the amount of wear, if the material (hardness) and shape (diameter and circularity) are the same, the amount of wear should be the same, and it is considered that the difference in diameter between the two is involved. For the time being, the marginal wear remaining amount of nominal 32 mm diameter is 2
Assuming a diameter of 8.8 mm, the conventional product reaches the limit wear limit in 18,400 times. If the reduction of 10% is about 5 years, 18,000 times in acceleration test corresponds to about 5 years. It will be. When the product of the present invention is applied to this,
This corresponds to 40,000 times, that is, about 11 years, which is a service life almost the same as the ship service life (see FIG. 12).

[0022]

[Table 1]

[Brief description of drawings]

FIG. 1 is a process drawing showing a manufacturing method according to the present invention.

FIG. 2 is a plan view of an approximately θ-shaped die forging link used in the method of the present invention.

FIG. 3 is a plan view of an approximately ε-shaped die forging link used in the method of the present invention.

FIG. 4 is a plan view showing an open-end joined state of the die forged link shown in FIG.

FIG. 5 is a process drawing showing a method of manufacturing a conventional stud link chain.

FIG. 6 is a schematic diagram showing a wear rate of a link.

FIG. 7 is a plan view of an apparatus for performing bending when connecting a die forging link having a substantially ε shape according to the present invention.

8 is a cross-sectional view taken along the line AA of FIG.

FIG. 9 is a perspective view showing a state before placing a substantially ε-shaped die forged link on a lower holding and pushing metal fitting and inserting substantially θ-shaped die forged links at both ends thereof before bending.

FIG. 10: A pair of holding metal fittings are overlapped with each other, and a pair of metal fittings (one is omitted) at the corners on the extrusion side.
FIG. 3 is a perspective view of a state in which is rotatably arranged.

FIG. 11 is a graph showing the relationship between the number of times of friction and the amount of wear in a wear test.

FIG. 12 is a graph showing a relationship between the number of frictions and a wear rate in a wear test.

[Explanation of symbols]

 1 Completed Link 2 Intermediate Link 11, 21 Link Outer Part 12, 22 Stud Part 13, 23 Shoulder Part 24 Open End 25 Joined Part 5 Clamping Pushing Metal Fitting 51 Clamping Part 51a Tip Part 51b Inclined Side Surface 6 Abutting Metal Fitting 61 Abutting Member 62 Rotating Shaft

Claims (6)

[Claims] 1. One of the connected stud links is molded by die forging into a substantially θ-shaped completed stud link 1 in which a link portion 11 and a stud portion 12 are integrally formed, while the other stud link is die forged. By link part 2
1 and one of the fixed portions of the stud portion 22 are opened to form a substantially ε-shaped intermediate stud link 2 having a pair of link open ends 24, 24 and a stud open end 22b, and each intermediate stud link 2 is opened. The ends 24, 24 are inserted into the respective cavities 13, 14 of the adjacent completed stud links 1, 1 to be combined, and the stud portion 22 of the intermediate stud link 2 is inserted.
Long side link portion 21 extending outward from the fixed end 22a of the
B and 21B are bent inward at an angle of 45 ° or less to form a substantially θ shape, and at least the abutting portions 25 of the open ends 24 and 24 are welded and connected to each other to form a forged stud link chain. Production method. 2. The forged and intermediate stud links are die forged such that outer peripheral link short side portions 11A, 21A have a width direction diameter larger than an average diameter and link long side portions 11B, 21A have a width direction diameter smaller than an average diameter. The manufacturing method according to claim 1. 3. A substantially θ-shaped completed stud link 1 formed by die forging, and 45 formed by die forging.
The butt portion 25 of the intermediate stud link 2 that is abutted by bending is welded by combining the intermediate stud link 2 that is partially opened and has a substantially ε shape that can be formed into a substantially θ shape by bending within 0 °. A forged stud link chain that has been chained. 4. The die forging of the finished and intermediate stud links is such that the outer peripheral link short side portions 11A, 21A have a width direction diameter larger than the average diameter and the link long side portions 11B, 21A have a width direction diameter smaller than the average diameter. The manufacturing method according to claim 1. 5. The forged stud chain according to claim 3, wherein the stud portions of the completed and intermediate stud links have mounting holes. 6. A fixed end 22 of the stud portion 22 is formed by sandwiching a substantially ε-shaped intermediate stud link 2 between its stud portions 22.
The long side link portions 21B extending from the a to the left and the right are abutted against the pair of holding push fittings 5 and 5 for pushing the long side link portions 21B from the inside to the outside and the pair of curved portions 21C extending from the long side link portions 21B to the both short side link portions 21A. It is composed of a pair of metal fittings 6, 6 swingable around a rotation axis perpendicular to the plane L including the intermediate stud link 2, and the stud fixing of the approximately ε-shaped intermediate stud link 2 of the pressing metal fittings 4, 4. End 22a
The pushing force to the long side link portion 21B in the vicinity is received by the first portions of the pair of metal fittings 6, 6 that abut on the curved portions 21C on both sides thereof, and the short portion of the second portion accompanying the receiving operation of the metal fittings 6, 6 is received. An apparatus for manufacturing a cast stud chain, which is capable of bending the open ends 24, 24 into a substantially θ shape by pushing the side link portion 21A inward.