chain

Abstract

To provide a chain which is excellent in wear resistance.SOLUTION: A bush 7 is a cylindrical member having a hole 19, and having a substantially rectangular cross-sectional shape in a cross section orthogonal to an axial direction. A sleeve 13 is provided at an external periphery of the bush 7. The sleeve 13 is a substantially cylindrical member having a hole 21, and an inner face shape of the hole 21 is a substantially rectangular shape corresponding to an outer face shape of the bush 7. The outer face shape of the sleeve 13 is formed into a substantially circular shape, and a roller 15 is provided at an external periphery of the sleeve 13. The roller 13 is formed into a substantially cylindrical shape, and rotatable with respect to the sleeve 13. Here, it is preferable that the hardness (for example, Rockwell hardness HRC) of the sleeve 13 be higher than the hardness of the bush 7.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a roller chain having excellent wear resistance. [Background technology]

[0002] Conventionally, chains are made up of multiple outer and inner plates connected to each other via pins and bushings, and rollers are sometimes used on the outer periphery of the bushings. In this case, both ends of the bushings are press-fitted into the inner plates to fix them, and the rollers rotate relative to the bushings.

[0003] When using such rollers, wear between the roller and bushing becomes an issue. For this reason, it is necessary to select a material with high hardness and high wear resistance. However, because bushings and other components are subjected to force and impact during use, if they are made entirely of a material with high hardness, there is a risk of cracking.

[0004] In order to achieve both mechanical properties and wear resistance, a method has been proposed in which a wear-resistant layer is formed on the surface of a bushing, roller, or the like (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-43837 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, forming a wear-resistant layer on the surface of the components that make up a chain requires special processes, such as diffusing nitrogen or other materials from the surface of the component, or laminating the wear-resistant layer on the surface using PVD or plating. Furthermore, methods that form a wear-resistant layer on the surface of the component have limitations on the thickness of the layer that can be formed, making it difficult to ensure a sufficient thickness. Therefore, even if high wear resistance can be achieved for a certain period of time after the start of use, once the wear-resistant layer wears, there is a risk that the base material will rapidly wear out.

[0007] The present invention has been made in view of these problems, and has as its object to provide a chain with excellent wear resistance. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the present invention provides a chain in which a plurality of plates are connected, the chain comprising: bushings, both ends of which are fitted into the plates at the connection portions between the plates; a sleeve, which is provided on the outer periphery of the bushing and has a rotation restriction structure relative to the bushing; and a roller, which is provided on the outer periphery of the sleeve and is arranged rotatably relative to the sleeve. The roller has an outer peripheral portion and an inner peripheral portion disposed on the inner side of the outer peripheral portion, the size of the outer peripheral surface of the inner peripheral portion of the roller is smaller than the size of the inner peripheral surface of the outer peripheral portion of the roller, the inner peripheral portion of the roller has play with respect to the outer peripheral portion of the roller, the outer peripheral portion of the roller and the inner peripheral portion of the roller do not rotate relative to each other, and the inner peripheral portion of the roller is rotatable with respect to the sleeve. This is a chain characterized by the following. The second invention is a chain in which a plurality of plates are connected, and at the connection portion between the plates, the chain comprises a bushing whose both ends are fitted into the plates, a sleeve provided on the outer periphery of the bushing and having a rotation restriction structure relative to the bushing, and a roller provided on the outer periphery of the sleeve and arranged rotatably relative to the sleeve, wherein the roller and the sleeve can be divided into multiple pieces circumferentially, and the circumferentially divided sleeves are not joined together.

[0009] The bushing may have an outer surface that is substantially polygonal, and the sleeve may have an inner surface that corresponds to the outer surface of the bushing.

[0010] It is desirable that the size of the outer peripheral surface of the bushing be equal to or smaller than the size of the inner peripheral surface of the sleeve.

[0011] The roller may have an outer peripheral portion and an inner peripheral portion arranged on the inner side of the outer peripheral portion, and the outer peripheral portion and the inner peripheral portion may not rotate relative to each other, but the inner peripheral portion may be rotatable relative to the sleeve.

[0013] 1st and 2ndAccording to the present invention, since the sleeve is provided on the outer periphery of the bushing, a wear-resistant layer having a sufficient thickness can be formed on the outer periphery of the bushing compared to ordinary surface treatments, and therefore wear can be suppressed for a sufficiently long period of time. Furthermore, by making the roller a two-layer structure, it is possible to suppress wear on the inner peripheral surface of the roller that rotates and slides against the sleeve.

[0014] Furthermore, by forming the outer surface of the bushing into a substantially polygonal shape and forming the inner surface of the sleeve into a shape that corresponds to the outer surface shape of the bushing, it is possible to reliably suppress rotation of the bushing and the sleeve.

[0015] Furthermore, by making the size of the outer circumferential surface of the bushing equal to or smaller than the size of the inner circumferential surface of the sleeve, there is no need to press-fit the bushing into the sleeve. For example, it is desirable to have a slight clearance between the outer circumferential surface of the bushing and the inner circumferential surface of the sleeve, so that there is some play. Note that making the size of the outer circumferential surface of the bushing equal to or smaller than the size of the inner circumferential surface of the sleeve means eliminating bushings that cannot be inserted without being press-fitted into the sleeve, and does not necessarily mean that play is required.

[0016] Furthermore, by making the roller a two-layer structure, it is possible to suppress wear on the inner peripheral surface of the roller that rotates and slides against the sleeve. [Effects of the Invention]

[0018] According to the present invention, a chain with excellent wear resistance can be provided. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. [Figure 2] 2A is a cross-sectional view of the chain 1 taken along line AA in FIG. 1, and FIG. 2B is a cross-sectional view of line BB in FIG. [Figure 3] 1A is a perspective view of the bushing 7, and FIG. 1B is a perspective view of the sleeve 13. FIG. [Figure 4] 1A is a cross-sectional view showing another embodiment of the chain, and FIG. 1B is a cross-sectional view taken along line CC of FIG. [Figure 5]1A is a perspective view showing an inner peripheral portion 15a of the roller, and FIG. 1B is a perspective view showing an outer peripheral portion 15b of the roller. [Figure 6] 1A is a perspective view showing a divided sleeve 13, and FIG. 1B is a perspective view showing a divided roller 15. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a perspective view of a chain 1 according to this embodiment, Fig. 2(a) is a cross-sectional view taken along line AA in Fig. 1, and Fig. 2(b) is a cross-sectional view taken along line BB in Fig. 2(a). The chain 1 is mainly composed of plates 3, pins 5, bushings 7, sleeves 13, rollers 15, etc.

[0021] The plate 3 is a plate-like member and is composed of an outer plate 4 and an inner plate 6. A pair of outer plates 4 and a pair of inner plates 6 are arranged alternately. Pin fitting holes 9 are provided near both ends of the outer plate 4. Furthermore, bushing fitting holes 11 are provided near both ends of the inner plate 6.

[0022] FIG. 3(a) is a perspective view showing the bushing 7. The bushing 7 is a cylindrical member having a hole 19 and a generally rectangular cross section perpendicular to the axial direction. The outer surface shape of the bushing 7 is not limited to a generally rectangular shape, and may be any other shape as long as it is generally polygonal. A generally polygonal shape includes a shape in which corners are rounded. Press-fit portions 17 are provided at both ends of the bushing 7.

[0023] At the connection between the outer plate 4 and the inner plate 6, a pair of inner plates 6 are arranged opposite each other, and the press-fit portions 17 at both ends of the bushing 7 are fitted into the bushing fitting holes 11. The pair of outer plates 4 are also arranged outside the inner plates 6, and a pin 5 that passes through the bushing 7 is fixed in the pin fitting hole 9 at a position corresponding to the bushing fitting hole 11. In other words, the pair of outer plates 4 and the pair of inner plates 6 are connected to each other near both ends by the pin 5. In this way, the chain 1 is formed by connecting multiple outer plates 4 and inner plates 6 rotatably around the pin 5.

[0024] A sleeve 13 is provided on the outer periphery of the bushing 7. There may be some play between the bushing 7 and the sleeve 13. The sleeve 13 is a generally cylindrical member in which a hole 21 is provided, and the inner shape of the hole 21 is a generally rectangular shape that corresponds to the outer shape of the bushing 7. In other words, the sleeve 13 and the bushing 7 have a rotation restricting structure that restricts relative rotation between them.

[0025] The rotation restricting structure restricts the rotation of the sleeve 13 relative to the bushing 7 by making the outer surface shape of the bushing 7 approximately polygonal and making the inner surface shape of the sleeve 13 a shape corresponding to the outer surface shape of the bushing 7, but is not limited to this. For example, if the outer surface of the bushing 7 and the inner surface of the sleeve 13 are not perfectly circular but have a circumferentially uneven shape (including a flat shape) that can restrict rotation, then a rotation restricting structure can be formed.

[0026] The outer surface of the sleeve 13 is substantially circular, and a roller 15 is disposed on the outer periphery of the sleeve 13. The roller 15 is substantially cylindrical and is rotatable relative to the sleeve 13. The outer diameter of the roller 15 is larger than the height of the plate 3, for example, and the roller 15 is formed so that the outer periphery of the roller 15 protrudes from the plate 3.

[0027] Here, it is desirable that the hardness of the sleeve 13 be higher than that of the bushing 7. For example, the Rockwell hardness of the sleeve 13 may be 56 to 63 HRC, and the Rockwell hardness of the bushing 7 may be 35 to 45 HRC. This makes it possible to improve the wear resistance compared to the bushing 7 alone. As such materials, for example, the bushing 7 and roller 15 may be made of SUS403, and the sleeve 13 may be made of SUS440C. In this case, surface treatment such as carburizing is not required on the outer peripheral surface of the bushing 7.

[0028] As described above, according to this embodiment, the sleeve 13 is disposed on the outer periphery of the bushing 7, so that it is possible to more reliably improve the wear resistance compared to the case where a wear-resistant layer is formed only by surface treatment on the outer periphery of the bushing 7. Furthermore, since it is not necessary to increase the hardness of the inner bushing 7 more than necessary, it is possible to suppress the occurrence of cracks in the bushing 7.

[0029] Furthermore, the rotation of the sleeve 13 relative to the bushing 7 is restricted by the rotation restricting structure. Therefore, rotational sliding between the bushing 7 and the sleeve 13 does not occur. For example, if the bushing 7 and the sleeve 13 were simply inserted without a rotation restricting structure (shape) and without press-fitting or the like, they would slide against each other, causing wear. In this way, the rotation restricting structure prevents sliding between the bushing 7 and the sleeve 13, and wear of the bushing 7 can be suppressed.

[0030] Furthermore, by making the size (outer diameter) of the outer peripheral surface of the bushing 7 equal to or smaller than the size (inner diameter) of the inner peripheral surface of the sleeve 13, there is no need to press-fit the bushing into the sleeve. As such, as long as the bushing 7 has some play with respect to the sleeve 13, it can be easily inserted into the sleeve 13 by hand. This improves assembly workability. Furthermore, because the bushing 7 is not press-fitted into the sleeve 13, the bushing 7 is not constantly subjected to press-fit stress from the sleeve 13 from the outer periphery. For example, if the bushing 7 and the sleeve 13 were integrated by press-fitting without a rotation-restricting structure (shape), the bushing 7 and the sleeve 13 would be constantly under stress, which could result in damage. Thus, even when the bushing 7 is subjected to external force from the sleeve 13 during use, the absence of press-fit stress allows for greater durability.

[0031] Furthermore, as a rotation restriction structure, the outer surface shape of the bushing 7 and the inner surface shape of the sleeve 13 are made substantially polygonal, so that when the sleeve 13 and the bushing 7 are subjected to a force in the direction of relative rotation, the force in the direction of rotation can be dispersed in the circumferential direction of the bushing 7 and the sleeve 13. This makes it possible to prevent damage to the bushing 7 and the like.

[0032] Next, a second embodiment will be described. Figure 4(a) is a cross-sectional view of a chain according to the second embodiment, and Figure 4(b) is a cross-sectional view taken along line CC in Figure 4(a). In the following description, the same components as those in chain 1 are given the same reference numerals as in Figures 1 to 3, and redundant description will be omitted.

[0033] The chain according to the second embodiment has a configuration similar to that of the chain 1 according to the first embodiment, but differs in the shape of the rollers 15. In this embodiment, the rollers 15 are configured with an inner peripheral roller portion 15a and an outer peripheral roller portion 15b as separate bodies. The inner peripheral roller portion 15a is disposed on the inner surface side of the outer peripheral roller portion 15b. In other words, the rollers 15 have a two-layer structure.

[0034] Fig. 5(a) is a perspective view showing the roller inner peripheral portion 15a, and Fig. 5(b) is a perspective view showing the roller outer peripheral portion 15b. The roller inner peripheral portion 15a is generally cylindrical and has a hole 23, with the inner surface shape being generally circular and the outer surface shape being generally rectangular. As described above, the sleeve 13 is inserted into the hole 23 of the roller inner peripheral portion 15a, and the two portions are rotatable relative to each other.

[0035] The roller outer circumferential portion 15b has a generally cylindrical shape with holes 24, an approximately rectangular inner surface, and an outer surface shape that forms the outer surface shape of the roller 15. In other words, the holes 24 have a shape that corresponds to the outer surface shape of the roller inner circumferential portion 15a. This makes it possible to restrict relative rotation between the roller inner circumferential portion 15a and the roller outer circumferential portion 15b. Note that, like the rotation restricting structure between the bushing 7 and the sleeve 13, the rotation restricting structure between the roller inner circumferential portion 15a and the roller outer circumferential portion 15b is not limited to an example in which the inner and outer surface shapes are generally rectangular, and may be other generally polygonal shapes or other uneven shapes.

[0036] It is desirable that the hardness of the roller inner peripheral portion 15a be higher than that of the roller outer peripheral portion 15b. That is, similar to the sleeve 13 for the bushing 7, the roller inner peripheral portion 15a can provide higher wear resistance than the roller outer peripheral portion 15b alone. For example, the roller outer peripheral portion 15b can be made of SUS403, and the roller inner peripheral portion 15a can be made of SUS440C.

[0037] According to the second embodiment, it is possible to obtain the same effects as those of the first embodiment. Furthermore, by disposing the roller inner peripheral portion 15a, which has a relatively high hardness, on the inner surface side of the roller 15, it is possible to suppress wear due to rotational sliding with the sleeve 13. In this case, since it is not necessary to increase the hardness of the roller outer peripheral portion 15b more than necessary, it is possible to suppress the occurrence of cracks and the like in the roller outer peripheral portion 15b.

[0038] Furthermore, since there is no rotational sliding between the roller inner peripheral portion 15a and the roller outer peripheral portion 15b, wear between the roller inner peripheral portion 15a and the roller outer peripheral portion 15b can be suppressed. Furthermore, by making the size (outer diameter) of the outer peripheral surface of the roller inner peripheral portion 15a equal to or smaller than the size (inner diameter) of the inner peripheral surface of the roller outer peripheral portion 15b, there is no need to press-fit the roller inner peripheral portion 15a into the roller outer peripheral portion 15b. As such, if the roller inner peripheral portion 15a has some play relative to the roller outer peripheral portion 15b, the assembly workability of the roller 15 is good. Furthermore, since the roller inner peripheral portion 15a is not press-fitted into the roller outer peripheral portion 15b, the roller inner peripheral portion 15a is not constantly subjected to stress due to the press-fit. Therefore, even when the roller inner peripheral portion 15a is subjected to external force from the roller outer peripheral portion 15b during use, the absence of stress due to the press-fitting allows for greater durability.

[0039] Furthermore, by forming the outer surface shape of the roller inner peripheral portion 15a and the inner surface shape of the roller outer peripheral portion 15b into a substantially polygonal shape as a rotation restriction structure, when the roller outer peripheral portion 15b and the roller inner peripheral portion 15a are subjected to a rotational force, the rotational force can be dispersed in the circumferential direction of the roller inner peripheral portion 15a and the roller outer peripheral portion 15b, thereby suppressing damage to the roller inner peripheral portion 15a, etc.

[0040] Next, a third embodiment will be described. Fig. 6(a) is a perspective view showing a sleeve 13 according to the third embodiment, and Fig. 6(b) is a perspective view of a roller 15 according to the third embodiment. In the third embodiment, the roller 15 and the sleeve 13 can be divided into multiple parts in the circumferential direction.

[0041] As shown in FIG. 6(a), the sleeve 13 is divided into two circumferentially into a segment 14a and a segment 14b. The segment 14a and the segment 14b are opposed to each other and butted together to form the generally cylindrical shape of the sleeve 13. Note that the opposed surfaces of the segments 14a and 14b may be formed with projections and recesses to facilitate alignment. The segments 14a and 14b may be joined to each other with bolts or the like, but a joining structure is not necessarily required.

[0042] As shown in Figure 6(b), roller 15 is divided into three circumferential portions: segment 16a, segment 16b, and segment 16c. In this embodiment, a flange 25 having a relatively large outer diameter is disposed on one end face of roller 15, and a cylindrical portion 27 having a smaller outer diameter than flange 25 is disposed on the back surface of flange 25. Segment 16a has flange 25 protruding in the circumferential direction from one circumferential end, and segment 16b has cylindrical portion 27 protruding in the circumferential direction from the circumferential end opposite to the protruding flange 25 of segment 16a. In other words, on one opposing side of segments 16a, 16b, the concave-convex structures of flange 25 and cylindrical portion 27 are configured to mesh with each other.

[0043] On the other hand, at the other opposing side of the segments 16a, 16b, the tubular portions 27 protrude in the circumferential direction and butt against each other. The segment 16c, which constitutes part of the flange 25, is placed on the end faces of the tubular portions 27 that protrude from each other at the opposing portions. In other words, the tubular portion 27 is constituted by the segments 16a, 16b, and the flange 25 is constituted by the segments 16a, 16b, and 16c.

[0044] A plurality of fixing holes 31 are formed in the divided body 16c, and fixing holes 29 are formed in corresponding positions on the end faces of the cylindrical portions 27 of the divided bodies 16a and 16b. The divided body 16c is arranged so as to straddle the divided bodies 16a and 16b, and bolts or the like are inserted into the fixing holes 31 and 29, thereby fixing the divided body 16c to the divided bodies 16a and 16b. In other words, the divided bodies 16a, 16b, and 16c are joined together to form the substantially cylindrical roller 15.

[0045] According to the third embodiment, it is possible to obtain the same effects as in the first embodiment. Furthermore, by making the sleeve 13 and the rollers 15 separable in the circumferential direction, it is possible to replace the sleeve 13 and the rollers 15 without disassembling the plates 3 of the chain. Therefore, for example, when wear progresses on the outer surface of the sleeve 13 or the inner and outer surfaces of the rollers 15, it is possible to easily replace the sleeve 13 and the rollers 15.

[0046] In this case, the sleeve 13 is placed inside the roller 15 and is held from the outer periphery, so there is no need to join the divided bodies 14a and 14b. Therefore, bolts and the like are not required, and the attachment and detachment work is easy.

[0047] Furthermore, the segments 14a and 14b can be members of the same shape. Here, because the sleeve 13 itself does not rotate, the sleeve 13 is always in strong contact with the roller 15 at a substantially constant position in the circumferential direction. Therefore, for example, if wear of one segment 14a progresses, the position of the segment 14a can be simply swapped with the position of the segment 14a, so that the portion with little wear can be brought into contact with the roller 15.

[0048] The number of divisions of the sleeve 13 and the roller 15 is not limited to the example shown in the figure. Furthermore, the method of dividing the roller 15 is not limited to the method shown in the figure, and the flange portion 25 and the cylindrical portion 27 do not have to be shifted in the circumferential direction to be engaged. Furthermore, in addition to dividing the roller 15 in the circumferential direction, it may also be further divided into a roller inner peripheral portion 15a and a roller outer peripheral portion 15b.

[0049] Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical scope of the present invention is not limited to the above-described embodiments. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the technical ideas described in the claims, and it is understood that these modifications and alterations also fall within the technical scope of the present invention.

[0050] For example, the chain of the present invention is not limited to the illustrated example, but can also be applied to so-called offset chains. In an offset chain, one end of the plate is an outer plate portion, and the other end is an inner plate portion. A step is provided between the outer plate portion and the inner plate portion. In other words, an offset chain has a configuration similar to that of chain 1, in which one outer plate 4 and one inner plate 6 are integrally formed. The structure of the present invention can also be applied in this case. [Explanation of symbols]

[0051] 1...Chain 3. Plate 4...Outer plate 5...Pin 6...Inner plate 7... Bush 9...Pin fitting hole 11....Bushing fitting hole 13...Sleeve 14a, 14b, 16a, 16b, 16c...Divided bodies 15...Laura 15a...Inner circumference of roller 15b....Roller outer periphery 17...Press-fit section 19, 21, 23, 24……hole 25………Flange 27……Cylinder part 29, 31……Fixing hole

Claims

1. A chain in which multiple plates are connected, At the connection portion between the plates, a bushing whose both ends are fitted to the plate; a sleeve provided on an outer periphery of the bushing and having a rotation restriction structure relative to the bushing; a roller provided on an outer periphery of the sleeve and rotatably disposed relative to the sleeve; Equipped with The roller has an outer peripheral portion and an inner peripheral portion disposed on the inner side of the outer peripheral portion, a size of an outer peripheral surface of the inner peripheral portion of the roller is smaller than a size of an inner peripheral surface of the outer peripheral portion of the roller, and the inner peripheral portion of the roller has a play with respect to the outer peripheral portion of the roller; A chain characterized in that the outer peripheral portion of the roller and the inner peripheral portion of the roller do not rotate relative to each other, but the inner peripheral portion of the roller is rotatable with respect to the sleeve.

2. A chain in which multiple plates are connected, At the connection portion between the plates, a bushing whose both ends are fitted to the plate; a sleeve provided on an outer periphery of the bushing and having a rotation restriction structure relative to the bushing; a roller provided on an outer periphery of the sleeve and rotatably disposed relative to the sleeve; Equipped with the roller and the sleeve can be divided into a plurality of parts in the circumferential direction, A chain characterized in that the circumferentially divided sleeves are not joined to each other.

3. 3. The chain according to claim 1, wherein the outer surface of the bushing has a substantially polygonal shape, and the inner surface of the sleeve has a shape corresponding to the outer surface of the bushing.

4. 4. The chain according to claim 1, wherein the size of the outer circumferential surface of the bushing is equal to or smaller than the size of the inner circumferential surface of the sleeve.

5. The roller has an outer peripheral portion and an inner peripheral portion disposed on the inner side of the outer peripheral portion, 5. The chain according to claim 2, wherein the outer peripheral portion of the roller and the inner peripheral portion of the roller do not rotate relative to each other, but the inner peripheral portion of the roller is rotatable relative to the sleeve.

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