Chain

Abstract

A chain (11) is provided with a plurality of paired inner link plates (14), a plurality of paired outer link plates (15), a plurality of bushings (16), and a plurality of pins (18). The inner link plate (14) has two through holes (14a). Each bushing (16) is inserted into a through-hole (14a) in a corresponding pair of inner link plates (14). Each pin (18) is inserted into a corresponding bushing (16) in a rotatable manner. The inner link plate (14) has a tapered surface section (14a1) at the opening end of each of the two through holes (14a) on the outer link plate side. The ratio (B / A) of the depth (B) of the tapered surface portion to the distance (A) between the centers of the two through holes (14a) in the inner link plate (14) is 0.9% to 6%.

Description

Technical Field

[0001] This disclosure relates to a chain. Background Technology

[0002] Patent document 1 describes a type of chain. like Figure 12 As shown, the chain 61 includes a pair of inner link plates 62, a pair of bushings 63 that are press-fitted into the pair of inner link plates 62, a connecting pin 64 that is loosely fitted into the bushings 63, and a pair of outer link plates 65 that are press-fitted into the connecting pin 64. The above-mentioned components are arranged as a unit, in multiple and continuous configurations, thereby constituting the chain 61. Existing technical documents Patent documents

[0003] Patent Document 1: Japanese Patent Application Publication No. 2006-105325 Summary of the Invention The problem that the invention aims to solve

[0004] However, the chain 61 described in Patent Document 1, etc., is expected to have excellent durability. In order to achieve excellent durability, it is necessary to improve fatigue resistance. Solution for solving the problem

[0005] This disclosure discloses a chain comprising multiple pairs of inner link plates and multiple pairs of outer link plates, multiple cylindrical bushings, and multiple pins. The pairs of inner link plates and multiple pairs of outer link plates are arranged alternately along the length of the chain. Two of the inner link plates in each pair are arranged opposite each other. Each inner link plate has two through holes. Each bushing is inserted into the through holes of the corresponding pair of inner link plates. Each pin is rotatably inserted into the corresponding bushing. Two of the outer link plates in each pair clamp the inner link plates from the outside. The chain is characterized in that each inner link plate is arranged in a manner that is adjacent to each other in the length direction, and two corresponding pairs of outer link plates are arranged at both ends of each pin. The plurality of bushings and the plurality of pins are arranged such that there are two pins between the two outer link plates in each pair. The chain is characterized in that each inner link plate has a tapered portion at the opening end of each of the two through holes on the side of each outer link plate, and the ratio (B / A) of the depth (B) of the tapered portion to the distance (A) between the centers of the two through holes in the inner link plate is more than 0.9% and less than 6%. Attached Figure Description

[0006] Figure 1 This is an exploded perspective view schematically showing a portion of the chain in the first embodiment. Figure 2 This is a cross-sectional view schematically showing a portion of the chain in the first embodiment. Figure 3 This is a 3D view of the inner link plate. Figure 4 yes Figure 3 A sectional view of the 4-4 line portion. Figure 5 It is an exploded perspective view schematically representing a part of the chain of changes. Figure 6 It is a cross-sectional view schematically representing a portion of the chain of the modified example. Figure 7 This is a perspective view of the inner link plate of the second embodiment. Figure 8 yes Figure 7 A sectional view of the section along line 8-8. Figure 9 This is a three-dimensional view of the inner link plate of other modified examples. Figure 10 This is a three-dimensional view of the inner link plate of another modified example. Figure 11 This is a diagram showing the fatigue resistance of the chains in the embodiments and comparative examples. Figure 12 It is a decomposed stereoscopic view and stereoscopic view of a part of the existing technology chain. Detailed Implementation

[0007] <First Embodiment> A first embodiment of the chain specific to this disclosure will be described. like Figure 1 , 2 As shown, the chain 11 of the first embodiment includes a plurality of inner chain links 12 and a plurality of outer chain links 13 disposed in the length direction X of the chain 11. The plurality of inner chain links 12 and the plurality of outer chain links 13 are arranged alternately in the length direction X.

[0008] The inner link portion 12 includes a pair of inner link plates 14. The two inner link plates 14 are arranged opposite each other in the width direction Y, which is perpendicular to the length direction X of the chain 11, with a gap D1 between them. In addition, the inner link portion 12 includes a cylindrical bushing 16 and a cylindrical portion 17, wherein the bushing 16 is located between the two inner link plates 14, connecting the inner link plates 14 to each other, and the cylindrical portion 17 is rotatably inserted into the bushing 16.

[0009] The outer link portion 13 includes a pair of outer link plates 15. The two pairs of outer link plates 15 are arranged opposite each other in the width direction Y, perpendicular to the length direction X of the chain 11, with a gap D2 between them. Furthermore, the outer link portion 13 includes a rod-shaped pin 18, which is rotatably inserted into a bushing 16. The two pairs of outer link plates 15 are arranged to clamp two pairs of inner link plates 14 adjacent to each other in the length direction X from the outside, and are positioned at both ends of the pin 18. Two pins 18 are located between the two outer link plates 15 in each pair. Therefore, multiple pairs of inner link plates 14 and multiple pairs of outer link plates 15 are arranged alternately in the length direction X. The distance P1 between the axes of adjacent pins 18 in a pair of outer link plates 15 is not particularly limited, for example, it is between 1 mm and 100 mm. There is no particular restriction on the distance P2 between the centers of adjacent pins 18 in two adjacent pairs of chain links 15 along the length direction X, for example, it can be more than 1 mm and less than 100 mm. Hereinafter, the distances P1 and P2 between the centers of adjacent pins 18 are referred to as the spacing of chain 11.

[0010] The following details chain 11. <Inner Link Plate> like Figure 1 , 2 As shown, the inner link plate 14 is made of sheet metal. At both ends of the inner link plate 14 along its long side, the two outer sides along the long side are convex semi-circular shapes. The central portion of the inner link plate 14 along its long side is formed into a curved, constricted shape that curves from the two outer sides along the short side towards the central portion.

[0011] In the inner link plate 14, there is a pair of through holes 14a on both outer sides of the long side of the central part that is clamped in the long side direction. In detail, the inner link plate 14 has two through holes 14a arranged side by side along the long side direction of the inner link plate 14.

[0012] The distance between the centers of the two through holes 14a in the inner link plate 14 is equal to the distance P2 between the axes of adjacent pins 18 in two adjacent outer link plates 15 in the aforementioned length direction X. Hereinafter, the distance between the centers of the two through holes 14a in the inner link plate 14 is referred to as distance (A).

[0013] The distance between the centers of adjacent through holes 14a in two adjacent inner link plates 14 along the length direction X is equal to the distance P1 between the centers of adjacent pins 18 in a pair of outer link plates 15.

[0014] like Figure 2 As shown, the thickness T1 of the inner link plate 14 is not particularly limited, but it is preferably above 0.1 mm and below 80 mm. There is no particular limitation on the width of the inner link plate 14, but it is preferably between 0.9 mm and 80 mm. The width of the inner link plate 14 refers to the length of the inner link plate 14 in the short side direction, that is, the size of the part with the largest length in the short side direction, excluding the constricted part.

[0015] The inner diameter of the through hole 14a of the inner link plate 14 is configured to be slightly smaller than the outer diameter of the peripheral wall of the bushing 16, which will be described later. As will be described later, the two ends of the bushing 16 are pressed into the through holes 14a of the inner link plate 14, so that the two inner link plates 14 in a pair are arranged opposite each other with a gap D1.

[0016] The spacing D1 between the two inner link plates 14 in a pair is not particularly limited, but is preferably between 0.6 mm and 55 mm. like Figure 2 As shown, the direction in which the two inner link plates 14 in a pair face each other is referred to as the inner side of the chain 11, and their opposite direction is referred to as the outer side of the chain 11.

[0017] like Figures 1-4 As shown, each inner link plate 14 has two through holes 14a with a tapered portion 14a1 that extends over the entire circumference of the outer opening end on the side of the outer link plate 15. Furthermore, each through hole 14a does not have a tapered portion 14a1 at its inner opening end. The inner surface of the inner link plate 14 is flat.

[0018] By having a tapered portion 14a1 around the entire circumference of the opening end of the through hole 14a, the inner diameter of the through hole 14a in the opening end is slightly larger than the inner diameter of the through hole 14a in the portion other than the opening end.

[0019] like Figure 4 As shown, the depth (B) of the tapered portion 14a1 extending from the outer surface of the inner link plate 14 to the inner side of the inner link plate 14 is not particularly limited. The ratio (B / T1) of the depth (B) of the conical section 14a1 to the thickness T1 of the inner link plate 14 is not particularly limited, but is preferably 6% to 50%, and more preferably 20% to 40%.

[0020] The tilt angle of the tapered portion 14a1 relative to the thickness direction of the inner link plate 14, i.e., the angle of the tapered portion 14a1 when the thickness direction of the inner link plate 14 is set to 0°, is not particularly limited. The angle of the tapered portion 14a1 is preferably 10° to 70°, more preferably 20° to 60°, and most preferably 30° to 50°. The angle of the tapered portion 14a1 can be set, for example, to 45°.

[0021] The ratio (B / A) of the depth (B) of the conical section 14a1 to the distance (A) between the centers of the two through holes 14a in the inner link plate 14 is 0.9% to 6%. Preferably, the ratio (B / A) is 2% to 5.5%, and more preferably 3% to 5%.

[0022] <External Link Section> like Figure 1 , 2 As shown, the outer link plate 15 is made of sheet metal. At both ends of the long side of the outer link plate 15, the two outer sides in the long side direction are convex semi-circular shapes. The central portion of the outer link plate 15 in the long side direction is formed into a curved, constricted shape that curves from the two outer sides in the short side direction towards the central portion.

[0023] In the outer link plate 15, there is a pin insertion hole 15a on each of the two outer sides of the long side direction of the central part that is clamped in the long side direction. In other words, the outer link plate 15 has two pin insertion holes 15a arranged side by side along the long side direction of the outer link plate 15.

[0024] There is no particular limitation on the thickness T2 of the outer link plate 15, but it is preferably the same as the thickness T1 of the inner link plate 14. There is no particular limitation on the width of the outer link plate 15, but it is preferably the same as the width of the inner link plate 14.

[0025] The inner diameter of the pin insertion hole 15a is configured to be slightly smaller than the diameter T5 of the pin 18, which will be described later. As described later, by pressing the two ends of the pin 18 into the pin insertion holes 15a of the outer link plate 15, the two paired outer link plates 15 are arranged opposite each other in a way that they are spaced apart by a distance D2 in the width direction Y, which is perpendicular to the length direction X of the chain 11. The distance D2 is also referred to as the spacing between the paired outer link plates 15.

[0026] The spacing D2 between the paired outer link plates 15 is not particularly restricted, and is slightly larger than the spacing D3 between the outer sides of the paired inner link plates 14. The spacing D2 between the paired outer link plates 15 is preferably, for example, 0.45 mm or more and 85 mm or less.

[0027] <Bearing> like Figure 1 , 2 As shown, the bushing 16 has a cylindrical structure. Specifically, the bushing 16 has a cylindrical peripheral wall in a cross-section along the radial direction.

[0028] The bushing 16 and the pair of inner link plates 14 are separate structures, with the two ends in the axial direction pressed into the through holes 14a of the inner link plates 14 respectively. The thickness of bushing 16, that is, the thickness T3 of the peripheral wall of bushing 16, is not particularly limited, but is preferably above 0.05mm and below 5mm.

[0029] There is no particular limitation on the outer diameter of the bushing 16, that is, the outer diameter of the peripheral wall of the bushing 16, but it is preferably between 0.4 mm and 45 mm. There is no particular limitation on the inner diameter of the bushing 16, that is, the inner diameter of the peripheral wall of the bushing 16, but it is preferably 0.3mm or more and 35mm or less.

[0030] The length of the bushing 16 is not particularly limited, but it is preferably the same as or slightly less than the spacing distance D3 between the outer sides of the paired inner link plates 14. <Cylinder section> like Figure 1 , 2 As shown, the cylindrical portion 17 has a cylindrical structure. Specifically, the cylindrical portion 17 has a cylindrical peripheral wall in a cross-section along the radial direction.

[0031] The cylindrical portion 17 is rotatably inserted into the bushing 16. Specifically, the inner diameter of the peripheral wall of the cylindrical portion 17 is configured to be larger than the outer diameter of the peripheral wall of the bushing 16, so that the cylindrical portion 17 and the bushing 16 are loosely fitted together.

[0032] The thickness of the cylindrical portion 17, that is, the thickness T4 of the peripheral wall of the cylindrical portion 17, is not particularly limited, but is preferably 0.1 mm or more and 7 mm or less. There is no particular limitation on the outer diameter of the cylindrical part 17, that is, the outer diameter of the peripheral wall of the cylindrical part 17, but it is preferably 0.6 mm or more and 55 mm or less.

[0033] The inner diameter of the cylindrical part 17, that is, the inner diameter of the peripheral wall of the cylindrical part 17, is not particularly limited, but is preferably 0.4 mm or more and 45 mm or less. The length of the cylindrical portion 17, that is, the axial length in the peripheral wall of the cylindrical portion 17, is slightly less than the distance D1 between the paired inner link plates 14.

[0034] <Sales> like Figure 1 , 2 As shown, pin 18 has a rod-shaped structure. Specifically, pin 18 is cylindrical, and its radial cross-section is circular. Figure 2 , 6 This is a side view of pin 18.

[0035] In pin 18, both ends in the axial direction are inserted into pin insertion holes 15a of the outer link plate 15 and are pressed into the pin insertion holes 15a. In addition, the front ends of pin 18 in the axial direction pass through a pin insertion hole 15a of the outer link plate 15 and protrude outward in the width direction Y of the chain 11.

[0036] Pin 18 is rotatably inserted into bushing 16. Specifically, the diameter T5 of pin 18 is configured to be smaller than the inner diameter of the through hole 14a of inner link plate 14 and the inner diameter of the peripheral wall of bushing 16. Pin 18 is configured to be rotatable inside bushing 16.

[0037] There are no particular restrictions on the diameter T5 of pin 18, but it is preferably between 0.3mm and 35mm. There is no particular limitation on the length of pin 18, but it is preferably between 1.4mm and 350mm.

[0038] The upper limit of the distance P1, P2 between the centers of adjacent pins 18, i.e., the upper limit of the pitch, is not particularly limited, but is preferably, for example, 90 mm. Furthermore, the lower limit of the pitch is not particularly limited, but is preferably, for example, 0.9 mm.

[0039] The following describes the materials of each component that makes up chain 11. <Materials of the chain's components> The materials of the inner link plate 14, outer link plate 15, bushing 16, cylindrical part 17, and pin 18 of the structural components of chain 11 are not particularly limited, and known materials can be appropriately used as the material of chain 11.

[0040] Commonly known materials include metals and resins. Among these materials, metals are preferred because they offer higher mechanical strength. The manufacturing method of chain 11 will be described below.

[0041] <Chain Manufacturing Method> The manufacturing method of chain 11 includes a forming process of forming sheet metal or other materials into a predetermined shape, and an assembly process of assembling the constituent components obtained from the forming process. Each process will be described below.

[0042] (Forming process) The forming process uses sheet metal or other materials to form the various components. When forming the inner link plate 14 or the outer link plate 15, the aforementioned sheet metal is punched into a predetermined shape, for example. The through hole 14a of the inner link plate 14 or the pin insertion hole 15a of the outer link plate 15 can also be formed by punching. Simultaneously with forming the through hole 14a, a tapered portion 14a1 can be formed at the opening end outside the through hole 14a. Figure 4 In the middle, the conical surface 14a1 is formed in the state where the opening end is chamfered by the C surface.

[0043] Furthermore, when forming the bushing 16 or the cylindrical portion 17, for example, the aforementioned sheet metal is punched into a predetermined shape and then bent into a cylindrical shape. In other words, it is rolled into a cylindrical shape. Furthermore, after rolling, the ends of the sheet metal are joined together. Here, "joining the ends of the sheet metal together" means that the ends of the sheet metal are in a state of contact with each other.

[0044] When forming pin 18, for example, after drawing a metal bar, it is then cut to a specified length. After the forming process, heat treatment processes such as quenching can also be performed.

[0045] (Assembly process) The assembly process involves assembling the constituent components obtained in the forming process to produce the chain 11. like Figure 1 , 2 As shown, first, multiple inner link plates 14 are prepared, and then the bushings 16 are pressed into the two through holes 14a of each inner link plate 14.

[0046] Here, the bushing 16 is pressed into the inner link plate 14 from the open end side of the two through holes 14a of the inner link plate 14, where the tapered portion 14a1 is not formed. The bushing 16 is installed in the inner link plate 14 with one end side pressed into the through hole 14a in the axial direction. Preferably, one end side of the bushing 16 is located within the through hole 14a and does not protrude outward.

[0047] Next, the cylindrical portion 17 is inserted from the other end of the bushing 16 onto the bushing 16 already mounted on each inner link plate 14. Then, another inner link plate 14 is mounted from the other end of the bushing 16 onto the bushing 16 with the cylindrical portion 17 inserted. Specifically, the end of the bushing 16 with the cylindrical portion 17 inserted is pressed into the open end side of the two through holes 14a of the other inner link plate 14, where the tapered portion 14a1 is not formed. Preferably, the end of the bushing 16 is located within the through hole 14a and does not protrude outward.

[0048] The inner link portion 12 can be manufactured by following the above sequence. Since one end of the bushing 16 and the other end are both pressed into the through holes 14a of a pair of inner link plates 14, the through holes 14a formed on the pair of inner link plates 14 are connected to each other by the bushing 16. Multiple inner link portions 12 are manufactured by repeating the same sequence.

[0049] Next, prepare multiple outer link plates 15, and then press the pins 18 into the two pin insertion holes 15a of each outer link plate 15. The pins 18 are installed on the outer link plates 15 with the front end portion of one end protruding from the pin insertion hole 15a.

[0050] Next, prepare the two inner link sections 12 that have been made above. For one of the two inner link sections 12, insert one of the two pins 18 mounted on the outer link plate 15 into the bushing 16 of the inner link section 12.

[0051] Furthermore, for the other of the two inner link sections 12, the other pin 18 of the two pins 18 mounted on the outer link plate 15 is inserted into the bushing 16 of that inner link section 12. Additionally, the two pins 18 inserted into the bushings 16 of the two inner link sections 12 are mounted on another outer link plate 15. Specifically, the other ends of the two pins 18 inserted into the bushings 16 of the two inner link sections 12 are pressed into the two pin insertion holes 15a of the other outer link plate 15.

[0052] By following the above sequence, pin 18 can be engaged with the two pin insertion holes 15a of the two paired outer link plates 15. This allows the outer link portion 13 to be manufactured. Furthermore, two inner link portions 12 are connected to one outer link portion 13.

[0053] Repeating the above sequence, multiple inner link segments 12 and multiple outer link segments 13 are connected to each other in an alternating manner along the length direction X. Then, the two ends of the alternating inner link segments 12 and outer link segments 13 along the length direction X are connected to each other, thereby making the whole into a loop.

[0054] Chain 11 can be manufactured by following the above sequence. The order in which the components of chain 11 are assembled can be appropriately changed. <Functions and Effects> The function of the chain 11 in the first embodiment will be explained.

[0055] When the chain 11 is in use, the through hole 14a of the inner link plate 14 is directly subjected to stress from the bushing 16 pressed into the through hole 14a, or indirectly subjected to stress from the pin 18 inserted into the bushing 16. This stress tends to concentrate at the open end of the outer link plate 15 side in the through hole 14a of the inner link plate 14.

[0056] like Figure 3 , 4As shown, the inner link plate 14 of the first embodiment has a tapered portion 14a1 at the opening end outside the through hole 14a, thereby suppressing the phenomenon of stress concentration at the opening end of the through hole 14a. In particular, by setting the ratio (B / A) of the depth (B) of the tapered portion 14a1 to the distance (A) between the centers of the two through holes 14a of the inner link plate 14 to 0.9% or more and 6% or less, the fatigue resistance of the chain 11 can be better improved even for chains 11 with different distances (A).

[0057] On the other hand, if the through hole 14a has a tapered portion 14a1, the fitting pressure of the bushing 16 in the through hole 14a of the inner link plate 14 tends to decrease. In this embodiment, the chain 11 can better suppress the decrease in the fitting pressure of the bushing 16 in the through hole 14a by having a ratio (B / T1) of the depth (B) of the tapered portion 14a1 to the thickness T1 of the inner link plate 14 of 6% or more and 50% or less.

[0058] The effects of the chain 11 in the first embodiment will be explained. (1-1) The chain 11 comprises multiple pairs of inner link plates 14 and multiple pairs of outer link plates 15, multiple cylindrical bushings 16, and multiple pins 18. The pairs of inner link plates 14 and multiple pairs of outer link plates 15 are arranged alternately in the longitudinal direction X. Two inner link plates 14 in each pair are arranged opposite each other. Each inner link plate 14 has two through holes 14a. Each bushing 16 is inserted into the through hole 14a in the corresponding pair of inner link plates 14. Each pin 18 is rotatably inserted into the corresponding bushing 16. Two outer link plates 15 in each pair are arranged to clamp two pairs of inner link plates 14 adjacent to each other in the longitudinal direction X from the outside. Two corresponding pairs of outer link plates 15 are arranged at both ends of each pin 18. Multiple bushings 16 and multiple pins 18 are arranged such that two pins 18 are located between two outer link plates 15 in each pair. The inner link plate 14 has a tapered portion 14a1 at its open end on the side of the outer link plate 15 with the through hole 14a. The ratio (B / A) of the depth (B) of the tapered portion 14a1 to the distance (A) between the centers of the two through holes 14a in the inner link plate 14 is more than 0.9% and less than 6%.

[0059] Therefore, the fatigue resistance of the chain 11 can be improved. By improving the fatigue resistance, a chain 11 with excellent durability can be obtained. (1-2) The through hole 14a of the inner link plate 14 has a tapered portion 14a1, which allows lubricating oil to accumulate in the gap between the tapered portion 14a1 and the bushing 16. For example, lubricating oil supplied between the bushing 16 and the pin 18 that flows out between them can be accumulated in the gap. In this way, since the flow of lubricating oil to the outside of the chain 11 can be suppressed, the wear of the bushing 16 and the pin 18 can be easily reduced.

[0060] <Second Implementation> A second embodiment of the chain specific to this disclosure will be described. The following description focuses on the structure of the chain 11 that differs from that of the first embodiment, while the description of the same structure is omitted.

[0061] like Figure 7 , 8 As shown, the inner link plate 14 has a protrusion 14a2 near the conical portion 14a1. Specifically, the inner link plate 14 is continuous with the conical portion 14a1 and has a protrusion 14a2 covering the entire circumference of the conical portion 14a1. "Continuous with the conical portion 14a1" means that the protrusion 14a2 is located on the extension line of the surface of the conical portion 14a1. The protrusion 14a2 protrudes outward from the inner link plate 14 along its thickness direction.

[0062] like Figure 8 As shown in the cross-sectional view of the inner link plate 14, the protrusion 14a2 has a semi-circular cross-sectional shape with its outer side protruding in the protruding direction. The protrusion 14a2 is not limited to a completely semi-circular cross-sectional shape; it can also be a roughly semi-circular cross-sectional shape with its outer side curved upwards. Furthermore, the cross-sectional shape of the protrusion 14a2 is not limited to a semi-circle; it can also adopt any cross-sectional shape with its outer side protruding.

[0063] The ratio (C / A) of the height (C) of the protrusion to the distance (A) between the centers of the two through holes in the inner link plate is not particularly limited, but is preferably 0.05% to 0.9%. The ratio (C / A) is more preferably 0.1% to 0.5%, and most preferably 0.15% to 0.35%.

[0064] The width E of the radial protrusion 14a2 in the through hole 14a is not particularly limited, but it is preferably 0.05 mm to 3 mm, and more preferably 0.1 mm to 1 mm.

[0065] The method for forming the protrusion can be as follows: in the forming process of the chain manufacturing method of the first embodiment, when the conical surface 14a1 is formed by punching, a protrusion 14a2 that is continuous with the conical surface 14a1 is formed simultaneously. For example, when forming the conical surface 14a1, punching can be performed under the condition that the periphery of the conical surface 14a1 is raised, thereby simultaneously forming the conical surface 14a1 and the protrusion 14a2. The method for forming the protrusion 14a2 is not particularly limited, and it can also be formed by, for example, spraying, welding, forging, etc.

[0066] <Functions and Effects> The function of the chain 11 in the second embodiment will be explained. In addition to the functions of the chain 11 in the first embodiment, the chain 11 in the second embodiment can also perform the following functions.

[0067] By having a protrusion 14a2 that extends outward from the inner link plate 14 along its thickness direction, excessive interference between the inner link plate 14 and the outer link plate 15 can be suppressed. Specifically, the outer surface of the inner link plate 14 and the inner surface of the outer link plate 15 are not in surface contact, but rather in point contact or line contact at the top of the protrusion 14a2. This reduces the contact area between the outer surface of the inner link plate 14 and the inner surface of the outer link plate 15, thus suppressing heat generation caused by friction. By suppressing heat generation, the wear performance of the chain can be improved.

[0068] Furthermore, by setting the ratio (C / A) of the height (C) of the protrusion 14a2 to the distance (A) between the centers of the two through holes 14a in the inner link plate 14 to 0.05% or more and 0.9% or less, excessive interference between the inner link plate 14 and the outer link plate 15 can be better suppressed even when the distance (A) is different in the chain 11.

[0069] The effects of the chain 11 in the second embodiment will be explained. (2-1) The inner link plate 14 has a protrusion 14a2 on the surface of the outer link plate 15 side that is continuous with the tapered portion 14a1. Since the protrusion 14a2 can suppress excessive interference between the inner link plate 14 and the outer link plate 15, the wear performance of the chain 11 can be improved. In addition, since the slippage between the inner link plate 14 and the outer link plate 15 can be reduced, the noise of the chain 11 can also be reduced.

[0070] (2-2) The convex portion 14a2 is continuous with the tapered portion 14a1. Therefore, the convex portion 14a2 can be utilized as part of the tapered portion 14a1. Furthermore, since the convex portion 14a2 and the tapered portion 14a1 can be formed simultaneously, the production efficiency of the chain 11 can be improved.

[0071] (2-3) In the inner link plate 14, a tapered portion 14a1 is provided around the entire circumference of the opening end on the side of the outer link plate 15 of the through hole 14a, and a protrusion 14a2 is provided around the entire circumference of the tapered portion 14a1. By having the tapered portion 14a1 and the protrusion 14a2 around the entire circumference of the through hole 14a, the effects of the second embodiment can be achieved throughout the entire circumference of the through hole 14a.

[0072] (2-4) The ratio (C / A) of the height (C) of the protrusion 14a2 to the distance (A) between the centers of the two through holes 14a in the inner link plate 14 is more than 0.05% and less than 0.9%. Therefore, since excessive interference between the inner link plate 14 and the outer link plate 15 located outside the inner link plate 14 can be better suppressed, the wear performance of the chain 11 can be improved.

[0073] <Example of Change> The first and second embodiments (hereinafter collectively referred to as this embodiment) can be modified and implemented in the following ways. This embodiment and the following modifications can be combined and implemented with each other within the scope of technical non-contradiction.

[0074] • In this embodiment, the chain 11 has a cylindrical portion 17, but the cylindrical portion 17 may be omitted. like Figure 5 , 6 As shown, for example, the cylindrical part 17 of the chain 11 can be omitted, and the inner link part 12 of the chain 11 can also be composed of a pair of inner link plates 14 and a bushing 16 located between the pair of two inner link plates 14.

[0075] • In this embodiment, the inner link plate 14 has a protrusion 14a2 on the surface of the outer link plate 15 side that is continuous with the tapered surface 14a1, but it is not limited to this shape.

[0076] like Figure 9 As shown, the inner link plate 14 may also have a protrusion 14a2 on the surface of the outer link plate 15, close to the tapered portion 14a1 but spaced apart from the periphery of the tapered portion 14a1. By having the protrusion 14a2 spaced apart from the periphery of the tapered portion 14a1, the tapered portion 14a1 and the protrusion 14a2 can be easily formed separately. By forming the tapered portion 14a1 and the protrusion 14a2 separately, the dimensional accuracy of the above-mentioned parts can be easily improved.

[0077] • The convex portion 14a2 may not be formed continuously along the periphery of the conical portion 14a1. like Figure 10 As shown, for example, the protrusion 14a2 can also be formed in a discontinuous manner from the periphery of the conical surface 14a1 and with intervals between them. Figure 10In this configuration, the protrusion 14a2 is formed in a dome shape, or in other words, a hemispherical shape. By forming the protrusion 14a2 in a discontinuous manner, it is possible to selectively position the protrusion 14a2 in a more efficient manner.

[0078] like Figure 10 As shown, the protrusion 14a2 is preferably located in the region of the inner link plate 14 along the long side direction, including the inner diameter of the through hole 14a of the tapered portion 14a1, and also including the regions on both sides along the short side direction of the inner link plate 14. Figure 10 (Inside the dashed line indicated by the middle arrow). Since this area is prone to wear during use, a protrusion 14a2 is provided at least in the aforementioned area to easily suppress wear on the inner link plate 14 and the outer link plate 15.

[0079] In this embodiment, the through hole 14a of the inner link plate 14 has a tapered portion 14a1 and a protrusion 14a2 only at the outer opening end, but it is not limited to this shape. In addition to the outer opening end, the inner opening end may also have a tapered portion 14a1 and a protrusion 14a2. More specifically, the outer and inner shapes of the inner link plate 14 may also be the same.

[0080] • When the through hole 14a of the inner link plate 14 is formed by punching, the conical part 14a1 can be set on the fracture surface of the through hole 14a, or the conical part 14a1 can be set on the shear surface of the through hole 14a.

[0081] In this embodiment, the tapered portion 14a1 is formed around the entire circumference of the opening end outside the through hole 14a, but it is not limited to this shape. The tapered portion 14a1 may also be formed on a portion of the opening end outside the through hole 14a.

[0082] The ratio (B / T1) of the depth (B) of the conical section 14a1 to the thickness T1 of the inner link plate 14 is not limited to 6% or more and 50% or less. The ratio (B / T1) can be less than 10% or more than 50%.

[0083] In this embodiment, the conical portion 14a1 has a shape in which the opening end of the through hole 14a is chamfered by a C-face, but it is not limited to this shape. The shape of the conical portion 14a1 can be appropriately selected. For example, the conical portion 14a1 can be a shape in which the opening end of the through hole 14a is chamfered by an R-face, or it can be stepped.

[0084] In this embodiment, the bushing 16 is installed while being pressed into the through hole 14a of the inner link plate 14, but this configuration is not limited to this. The bushing 16 can also be welded into the through hole 14a of the inner link plate 14, or it can be installed using adhesive. The pin 18 can also be installed in the pin insertion hole 15a of the outer link plate 15 using the same method.

[0085] • Other forms of the chain 11 in this embodiment may be: the tapered portion 14a1 is omitted at the opening end outside the through hole 14a of the inner link plate 14, and a protrusion 14a2 is continuous with the opening end, or a protrusion 14a2 is provided near the opening end. Example

[0086] The following examples are provided to illustrate the structure and effects of this disclosure in more detail, but this disclosure is not limited to these examples. (Example 1) An inner link plate 14 is fabricated, wherein the thickness T1 is 13.15 mm, the inner diameter of each through hole 14a is 11.25 mm, the distance (A) between the centers of two through holes 14a is 25.4 mm, and a tapered portion 14a1 is provided at the opening end outside the through hole 14a. The depth (B) of the tapered portion 14a1 is 0.24 mm, and the ratio (B / A) is 0.94%. The inner link plate 14 has a protrusion 14a2 that is continuous with the tapered portion 14a1. The height (C) of the protrusion 14a2 is 0.025 mm, the ratio (C / A) is 0.1%, and the width E of the protrusion 14a2 is 1.6 mm.

[0087] Make an outer link plate 15, with a thickness T2 of 23.15 mm, an inner diameter of each pin insertion hole 15a of 7.85 mm, and a distance of 25.4 mm between the centers of two pin insertion holes 15a. Make a bushing 16 with a peripheral wall thickness of 1.65mm, an inner diameter of 8.1mm, an outer diameter of 11.4mm, and a length of 22.6mm.

[0088] A cylindrical part 17 is constructed with a peripheral wall thickness of 2.2 mm, an inner diameter of 11.5 mm, an outer diameter of 15.9 mm, and a length of 15.6 mm. Make pin 18 with a diameter of 7.9mm and a length of 32.5mm.

[0089] The chain 11 is made by assembling multiple of the above-mentioned components. (Examples 2-12, Comparative Examples 1-6) Except for changing the depth (B) and ratio (B / A) of the conical section 14a1 as shown in Table 1, the chain is manufactured using the same procedures as in Example 1.

[0090] (Evaluation of fatigue resistance) The fatigue resistance of the chains in Examples 1-7, 9-12, and Comparative Examples 1-5 was evaluated. Specifically, the effect of the ratio (B / A) of the depth (B) of the tapered section 14a1 to the distance (A) between the centers of the two through holes 14a of the inner link plate 14 on the fatigue resistance of the inner link plate 14 was evaluated.

[0091] The fatigue resistance was evaluated using a well-known fatigue testing machine according to JIS 1811B 2018, "Fatigue Test Method for Roller Chains and Plate Chains for Rotation". The analytical fatigue safety rate was determined and evaluated using the following evaluation criteria. The results are shown in Table 1. Figure 11 As shown.

[0092] • Evaluation criteria for fatigue resistance ◎(Good): Fatigue safety rate analyzed is above 2.1%. ○ (Acceptable): The fatigue safety rate is analyzed to be above 2.0 and below 2.1. × (Poor): The fatigue safety rate is less than 2.0. (Evaluation of the fitting and extrusion pressure of the bushing) The bushing fitting extrusion pressure was evaluated for the chains of Examples 1-12 and Comparative Examples 1-6. Specifically, the effect of the ratio (B / T1) of the depth (B) of the tapered section 14a1 to the thickness (T1) of the inner link plate 14 on the bushing fitting extrusion pressure was evaluated.

[0093] The method for evaluating the bushing's clamping extrusion force is to use a known tensile testing machine to determine the clamping extrusion force, which is the force required to push the bushing 16, which is pressed into the through hole 14a of the inner link plate 14, out of the bushing. The evaluation was conducted using the following evaluation criteria. The results are shown in Table 1.

[0094] Evaluation criteria for bushing fitting extrusion pressure ◎(Good): Fitting extrusion force above 4.0kN ○ (Acceptable): Clamping extrusion force above 3.0kN and below 4.0kN × (Defective): Clamping extrusion pressure is less than 3.0kN

[0095] Table 1

[0096] (Evaluation Results) From Table 1, Figure 11It can be seen that the ratio (B / A) of Comparative Examples 1 to 5 is less than 0.9% or more than 6%, indicating "poor" fatigue resistance. In contrast, the ratio (B / A) of Examples 1 to 7 and 9 to 12 is more than 0.9% and less than 6%, indicating "fair" or better fatigue resistance. In particular, the ratio (B / A) of Examples 5 to 7 and 9 to 11 is more than 2% and less than 5.5%, indicating "good" fatigue resistance.

[0097] Furthermore, as shown in Table 1, the ratio (B / T1) of Comparative Examples 5 and 6 exceeds 50%, and the fitting extrusion pressure is "poor". In contrast, the ratio (B / T1) of Examples 1 to 12 is 6% to 50%, and the fitting extrusion pressure is "acceptable" or higher. When the fitting extrusion pressure is "acceptable" or higher, that is, when the fitting extrusion pressure is 3.0 kN or higher, it can better prevent the bushing 16 from falling out of the through hole 14a of the inner link plate 14.

Claims

1. A chain comprising a plurality of paired inner link plates and a plurality of paired outer link plates, a plurality of cylindrical bushings, and a plurality of pins. The plurality of pairs of inner link plates and the plurality of pairs of outer link plates are arranged alternately along the length of the chain. The two inner link plates in each pair are arranged opposite each other. Each inner link plate has two through holes. Each bushing is inserted into the through hole in the corresponding pair of inner link plates. Each pin is rotatably inserted into its corresponding bushing. The two outer link plates in each pair are arranged to clamp from the outside onto two pairs of inner link plates that are adjacent to each other in the longitudinal direction. Two corresponding pairs of outer link plates are arranged at both ends of each pin. The plurality of bushings and the plurality of pins are arranged such that there are two pins between the two outer link plates in each pair. The chain is characterized in that: Each inner link plate has a tapered portion at the opening end on the side of each of the two through holes on the outer link plate side. The ratio (B / A) of the depth (B) of the conical section to the distance (A) between the centers of the two through holes in the inner link plate is more than 0.9% and less than 6%.

2. The chain according to claim 1, wherein Each inner link plate has a protrusion on the surface of the outer link plate that is continuous with the tapered surface.

3. The chain according to claim 2, wherein Each inner link plate has the tapered portion around the entire circumference of the opening end, and The protrusion is located around the entire circumference of the conical surface.

4. The chain according to claim 2 or 3, wherein The ratio (C / A) of the height (C) of the protrusion to the distance (A) between the centers of the two through holes in the inner link plate is more than 0.05% and less than 0.9%.

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