TW202004050A - Seal chain - Google Patents

Abstract

A seal chain (11) is provided with a pair of inner link plates (12), a bush (18) joined in a state where both ends protrude to the outside of the pair of inner link plates (12), a pin (21) inserted in to the bush (18), a pair of outer link plates (14) at which both ends of the pin (21) are joined to the outside of the pair of inner link plates (12), and an annular seal portion (32) disposed between the inner surfaces (14a) of the outer link plates (14) and the outer surfaces (12b) of the inner link plates (12). The seal portion (32) has a pin side seal ring (33) joined to the pin (21), a bush side seal ring (34) joined to the bush (18) and opposed to the pin side seal ring (33) in an axial direction of the pin (21), and seal members (35, 36) disposed between the pin side seal ring (33) and the bush side seal ring (34).

Description

Sealed chain

The present invention relates to a sealed chain in which a sealing portion is arranged between an outer side surface of an inner connecting plate and an inner side surface of the outer connecting plate.

Conventionally, such a sealed chain is known, for example, as shown in Patent Document 1. The sealing mechanism of such a sealed chain is composed of an annular seal carrier member made of steel, a first elastic seal ring, a steel seal ring, and a second elastic seal ring. The first elastic seal ring is externally fitted on the outer peripheral surface of the bush protruding from the outer side surface portion of the inner plate, and is disposed between the ring-shaped seal bearing member and the inner plate. The steel seal ring is arranged on the outer peripheral side of the ring-shaped seal bearing member and is in contact with the outer surface of the inner plate. The second elastic seal ring is sandwiched between the inner circumferential surface of the steel seal ring and the outer circumferential surface of the annular seal bearing member.

The ring-shaped seal bearing member has a disk-shaped seal bearing portion and a rim-shaped seal bearing portion. The disk-shaped seal bearing part is externally fixed to the connecting pin and abuts against the inner side of the outer plate, and is arranged between the end surface of the bush and the inner side of the outer plate. The rim-shaped seal bearing portion protrudes toward the inner plate on the outer peripheral side of the disk-shaped seal bearing portion.

Prior technical literature Patent Literature Patent Document 1: Japanese Patent Laid-Open No. 2008-157423

Problems to be solved by the invention However, when the above-mentioned sealed chain is used for a long period of time, the sliding surface between the connecting pin and the bushing wears out and causes the sealed chain to wear and extend. Since the ring-shaped seal carrier member will follow the connecting pin, the first The elastic seal ring is sandwiched between the outer peripheral surface of the bush and the rim-shaped seal bearing portion of the ring-shaped seal bearing member and worn. Furthermore, when the sliding surface between the connecting pin and the bushing is worn, the bushing will contact the rim-shaped sealing bearing portion of the annular seal-bearing member, so the tensile load of the sealed chain acts on the rim-shaped sealing bearing Ministry. Therefore, there is a problem that the rim-shaped seal bearing portion may be damaged.

An object of the present invention is to provide a sealed chain that can solve the problem that the pin-side seal ring and the bush-side seal ring may be damaged even if abrasion elongation occurs.

Means to solve the problem Hereinafter, the means for solving the above-mentioned problems and their effects will be described.

The sealed chain for solving the above-mentioned problems includes a pair of inner connecting plates, a cylindrical bush, a pin, a pair of outer connecting plates, and a ring-shaped sealing portion; the pair of inner connecting plates are arranged to face and separate from each other The cylindrical bush penetrates the pair of inner connecting plates, and is joined to the pair of inner connecting plates in a state where both ends protrude from the outer sides of the pair of inner connecting plates, respectively; The bush is rotatably inserted; a pair of the outer connecting plates are arranged so as to sandwich a pair of the inner connecting plates from the outside, and are respectively engaged with both ends of the pin; the ring-shaped The sealing portion is arranged so as to surround the pin and the bush between the outer surface of the inner connecting plate and the inner surface of the outer connecting plate; wherein the sealing portion includes an annular pin-side seal A ring, an annular bushing-side sealing ring, and an annular sealing member; the annular pin-side sealing ring is rotatably engaged with the pin; the annular bushing-side sealing ring is opposed The bushing is joined in an integrally rotatable manner and faces the pin-side seal ring in the axial direction of the pin; the ring-shaped seal member is sandwiched between the pin-side seal ring and the The arrangement between the seal rings on the bush side is described.

According to this configuration, when the sliding surface between the pin and the bushing wears out and causes the seal-type chain to wear and extend due to wear for a long time, the pin-side sealing ring will follow the pin and the bushing-side sealing ring will follow Because of the bushing, the pin-side seal ring and the bush-side seal ring are displaced relative to each other in a direction perpendicular to the axial direction of the pin with little interference. At this time, since the pin-side seal ring and the bush-side seal ring do not interfere with the bush and the pin, respectively, the tensile load of the sealed chain does not act on the pin-side seal ring and the bush-side seal ring. Therefore, it is possible to solve the problem that the seal ring on the pin side and the seal ring on the bush side may be damaged even if the seal type chain wears out.

In the above-mentioned sealing chain, it is preferable that a plurality of the sealing members having different outer diameters are arranged in a radial direction between the pin-side sealing ring and the bushing-side sealing ring.

According to this configuration, it is possible to improve the sealing performance of the sealing portion.

The above-mentioned sealing type chain is preferably: the pin-side seal ring is formed with an annular pin-side concave groove on the surface opposite to the bush-side seal ring, and the bush-side seal ring is on the pin side An annular bush-side concave groove is formed on the opposite surface of the seal ring, and the sealing member is sandwiched between the pin-side concave groove and the bush-side concave groove.

According to this configuration, the position of the sealing member can be determined, and the sealing performance of the sealing portion can be improved.

In the above-mentioned sealed chain, it is preferable that the depth of the pin-side concave groove and the bush-side concave groove in the radial direction is the deepest, and the depth is shallower toward the both ends in the radial direction.

According to this configuration, when the seal member sandwiched by both the radial center portion formed by the pin-side concave groove and the bush-side concave groove is worn and its cross-sectional area becomes small, the seal member and the pin-side concave groove Or, there will be a gap between the grooves on the side of the bush. In this state, if a foreign substance enters between the pin-side concave groove and the bush-side concave groove from the outer peripheral side of the seal member, the seal member will be pressed radially inward by the foreign substance. In this way, since the sealing member is sandwiched by both the radially inner ends formed by the pin-side concave groove and the bush-side concave groove, the seal member and the pin-side concave groove and the bush The gap between the undercut grooves will disappear. Therefore, even when the sealing member is worn and its cross-sectional area becomes small, the entry of foreign matter can be suppressed.

Invention effect According to the present invention, it is possible to solve the problem that the seal ring on the pin side and the seal ring on the bush side may be damaged even if the seal type chain wears out.

Hereinafter, one embodiment of the sealed chain will be described in accordance with the drawings.

As shown in FIG. 1, the sealed chain 11 includes, for example, a plurality of inner connecting portions 13 and a plurality of outer connecting portions 15 made of steel. Each inner coupling portion 13 has a pair of inner coupling plates 12 arranged so as to face and separate from each other in the width direction Y. Each outer connecting portion 15 has a pair of outer connecting plates 14 arranged so as to sandwich a pair of inner connecting plates 12 from the outside in the width direction Y.

The inner connecting plate 12 of the inner connecting portion 13 and the outer connecting plate 14 of the outer connecting portion 15 extend along an in-line direction X and assume a substantially rectangular plate shape. The in-line direction X, that is, the sealed chain 11 is extended from a length perpendicular to the width direction Y The direction of movement when one side pulls and moves. In addition, the inner connecting plate 12 and the outer connecting plate 14 facing in the width direction Y are arranged parallel to each other.

Therefore, the sealed chain 11 of this embodiment is a so-called flat chain. That is, each inner connecting portion 13 is configured such that the interval between the pair of inner connecting plates 12 is equal to one end side and the other end side of the inner connecting portion 13 in the in-line direction X, and each outer connecting portion 15 is configured as follows: The interval between the connecting plates 14 is equal to one end side to the other end side of the outer connecting portion 15 in the in-line direction X.

Circular bushing insertion holes 17 penetrating the width direction Y, which is the thickness direction of the inner connecting plate 12, are formed at both ends of the inner connecting plate 12 in the in-line direction X, respectively. Two cylindrical bushes 18 are assembled between the pair of inner connecting plates 12 facing each other in the inner connecting portion 13, and the cylindrical bushing 18 maintains the distance between the pair of inner connecting plates 12.

Both end portions of the bush 18 are fitted (joined) to the bush insertion holes 17 of the pair of inner connecting plates 12 so as to be unable to rotate, respectively. At this time, the front end portions of the both end portions of the bush 18 respectively protrude outward in the width direction Y from the pair of inner connecting plates 12. That is, the bush 18 penetrates the pair of inner connecting plates 12 at both ends. The bush 18 rotatably supports the roller 19 by being inserted into the cylindrical roller 19. That is, the bush 18 is loosely fitted to the roller 19.

Circular pin insertion holes 22 penetrating the width direction Y, which is the thickness direction of the outer connecting plate 14, are formed at both ends of the outer connecting plate 14 in the in-line direction X, respectively. A cylindrical pin 21 is inserted into the pin insertion hole 22, and the outer diameter of the pin 21 is slightly smaller than the inner diameter of the bush 18. A hole 23 is formed through the front end of the pin 21. This hole 23 is inserted with an anti-dropping pin 24 so that the pin 21 does not fall out of the pin insertion hole 22. The front end portion of the anti-dropout pin 24 is curved, and does not fall out of the hole 23 itself.

In addition, the pair of outer connecting plates 14 of the outer connecting portion 15 are disposed with respect to the inner connecting plate 12 of the inner connecting portion 13 through the pin 21 in a state where the pair of inner connecting plates 12 of the inner connecting portion 13 are disposed from the outside. Connected in a freely swinging manner, a bush 18 is assembled between a pair of inner connecting plates 12. At this time, in a state where the pin 21 is rotatably inserted into the bush 18 assembled between the pair of inner connecting plates 12 of the inner connecting portion 13 at the middle portion other than the both end portions, the two ends are connected to the outer portion The pin insertion holes 22 of the pair of outer connecting plates 14 of the portion 15 are respectively fitted (joined) so as not to be rotatable.

Therefore, both ends of the pin 21 respectively penetrate an outer connecting plate 14, wherein the inner connecting plate 12 of the inner connecting portion 13 adjacent to the in-line direction X and the outer connecting plate 14 of the outer connecting portion 15 pass the end of the in-line direction X The parts are connected to each other through the pin 21 and the bush 18 in a swingable manner.

A circular recess 26 is formed on the base end surface 25 of the pin 21. A communication path 27 extending linearly is formed from the center of the bottom surface of the concave portion 26 inside the pin 21 to the center of the pin 21 in the width direction Y in the axial direction. To the opening of the communication path 27 on the side of the recess 26, a grease joint 28 in which grease is injected into the communication path 27 in the past is attached.

A groove 29 extending in the width direction Y is formed in the outer peripheral surface 21a of the pin 21 at a position corresponding to the bush 18. The groove 29 communicates with the end of the communication path 27 opposite to the side of the recess 26 through the pin hole 30. Therefore, the communication path 27 communicates the grease joint 28 and the pin hole 30.

The recessed portion 26 of the pin 21 is detachably provided with a bottomed circular box-shaped top cover 31 made of a flexible material such as rubber. In a state where the top cover 31 is installed in the concave portion 26 of the pin 21, the top cover 31 covers the grease joint 28. A fine hole 31 a is formed through the center of the bottom wall of the top cover 31.

Grease as a lubricant is arranged between the outer circumferential surface 21a of the pin 21 and the inner circumferential surface 18a of the bush 18. Between the outer peripheral surface 21a of the pin 21 and the inner peripheral surface 18a of the bush 18, grease can be replenished from the grease joint 28 through the communication path 27, the pin hole 30, and the groove 29. Among them, an annular seal portion 32 is arranged between the outer side surface 12 b of the inner connecting plate 12 and the inner side surface 14 a of the outer connecting plate 14. The annular seal portion 32 is arranged so as to surround the pin 21 and the bush 18.

Next, the structure of the sealing portion 32 will be described in detail.

As shown in FIGS. 1 and 2, the seal portion 32 includes a metal pin-side seal ring 33 in the shape of an annular plate, a metal bush-side seal ring 34 in the shape of an annular plate, and an annular seal A large-diameter O-ring 35 as an example of a member, a square ring 36 as an example of an annular seal member, and an annular small-diameter O-ring 37.

The pin-side seal ring 33 is fitted (joined) to the pin 21 so as to be rotatable integrally, and the outer surface in the width direction Y is in contact with the inner side surface 14 a of the outer connecting plate 14. The bush-side seal ring 34 is fitted (engaged) with the bush 18 so as to be integrally rotatable, wherein the width direction Y in the axial direction of the pin 21 faces the pin-side seal ring 33. The inner surface of the bush side seal ring 34 in the width direction Y is in contact with the outer surface 12 b of the inner connecting plate 12. The bush side seal ring 34 and the pin side seal ring 33 do not overlap in the radial direction and the in-line direction X.

The large-diameter O-ring 35 and the small-diameter O-ring 37 have a circular shape in a cross-sectional view, and the square ring 36 has a rectangular shape in a cross-sectional view. The large-diameter O-ring 35 and the square ring 36 are arranged so as to be sandwiched between the pin-side seal ring 33 and the bush-side seal ring 34. The small-diameter O-ring 37 is arranged so as to be sandwiched between the pin-side seal ring 33 and the end surface 18b of the bush 18.

The large-diameter O-ring 35, the square ring 36, and the small-diameter O-ring 37 are made of flexible materials such as elastomers. Among the large-diameter O-ring 35, the square ring 36, and the small-diameter O-ring 37, the large-diameter O-ring 35 has the largest outer diameter and the small-diameter O-ring 37 has the smallest outer diameter. Therefore, the outer diameters of the large-diameter O-ring 35, the square ring 36, and the small-diameter O-ring 37 are different from each other, and are arranged side by side in the radial direction. The large-diameter O-ring 35, the square ring 36, and the small-diameter O-ring 37 are sufficiently coated with grease as a lubricant.

In the pin-side seal ring 33, as the facing surface 33a of the bush-side seal ring 34, pins corresponding to the large-diameter O-ring 35 and the square ring 36 are respectively formed as an example of an annular pin-side groove The first side concave groove 38 and the pin side second concave groove 39 which are an example of an annular pin side concave groove. The first groove 38 on the pin side has a substantially semi-elliptical shape in a cross-sectional view, and its bottom surface is pressure-contacted with the large-diameter O-ring 35. The first groove 38 on the pin side has the deepest depth in the radial center portion of the pin side seal ring 33, and the depth decreases toward both ends in the radial direction. The second groove 39 on the pin side is substantially U-shaped in a cross-sectional view, and is fitted at a position approximately halfway in the thickness direction (width direction Y) of the square ring 36.

A third groove 40 on the pin side is formed in the pin-side seal ring 33 at a position corresponding to the small-diameter O-ring 37 at the facing surface 33b as the end surface 18b of the bush 18. The third groove 40 on the pin side has a substantially semi-elliptical shape in a cross-sectional view, and its bottom surface is pressure-contacted with the small-diameter O-ring 37. The third groove 40 on the pin side has the deepest depth at the center portion of the pin side seal ring 33 in the radial direction, and the depth decreases toward both ends in the radial direction.

In the bush side seal ring 34, the facing surface 34a as the pin side seal ring 33 is formed with a bush side first recess 41 as an example of an annular bush side recess and an annular ring as a ring The bush-side second groove 42 is an example of the sleeve-side groove. The first groove 41 on the bush side has a substantially semi-elliptical shape in a cross-sectional view, and its bottom surface is pressure-contacted with the large-diameter O-ring 35. The first groove 41 on the bush side has the deepest depth in the center portion of the bush side seal ring 34 in the radial direction, and the depth decreases toward both ends in the radial direction. The second groove 42 on the bush side is substantially L-shaped in a cross-sectional view, and is fitted at a position approximately halfway in the thickness direction (width direction Y) of the square ring 36. At this time, the inner peripheral surface 36a of the square ring 36 is in contact with the outer peripheral surface 18c of the bush 18.

An annular bush groove 43 is formed in the end surface 18 b of the bush 18 at a position corresponding to the small-diameter O-ring 37. The bush groove 43 has a substantially semi-elliptical shape in a cross-sectional view, and its bottom surface is crimped with a small-diameter O-ring 37. The bush groove 43 has the deepest depth in the center portion of the bush side seal ring 34 in the radial direction, and the depth is shallower toward both ends in the radial direction.

The large-diameter O-ring 35 is sandwiched by both the central portion in the radial direction formed by the first concave groove 38 on the pin side and the first concave groove 41 on the bush side. The first concave groove 38 on the pin side and the first concave groove 41 on the bush side are formed in a shape consistent with each other. The square ring 36 is sandwiched between the second concave groove 39 on the pin side and the second concave groove 42 on the bush side. The second concave groove 39 on the pin side, the second concave groove 42 on the bush side, and the groove formed on the outer peripheral surface 18c of the bush 18 are formed in a shape almost identical to each other.

The small-diameter O-ring 37 is sandwiched by both the central portion in the radial direction formed by the third groove 40 on the pin side and the bush groove 43. The third groove 40 on the pin side and the groove 43 on the bush are formed in a shape consistent with each other. A slight gap S1 is formed between the facing surface 33 a as the bush side seal ring 34 in the pin side seal ring 33 and the facing surface 34 a as the pin side seal ring 33 in the bush side seal ring 34. A slight gap S2 is formed between the facing surface 33b as the end surface 18b of the bush 18 and the end surface 18b of the bush 18 in the pin side seal ring 33. The size of the gap S1 is almost the same as the size of the gap S2.

Next, the function of the sealed chain 11 will be described.

In a state where the circular sealed chain 11 is wound around a pair of sprockets (not shown) that are arranged separately from each other, when the sprocket on one side is rotated, the sealed chain 11 will be in a pair The periphery of the sprocket moves around. If the sealed chain 11 is used for a long time in this way, wear will occur between the outer peripheral surface 21a of the pin 21 and the inner peripheral surface 18a of the bush 18.

In this way, as the gap between the outer peripheral surface 21a of the pin 21 and the inner peripheral surface 18a of the bush 18 becomes larger, the sealed chain 11 is elongated, that is, the abrasion is elongated. When the sealed chain 11 wears out, the tensile load of the sealed chain 11 acts on the outer connecting plate 14 and the inner connecting plate 12 to reverse each other. In detail, the tensile load of the sealed chain 11 acts on the outer connecting plate 14 in the direction of one side of the in-line direction X, and acts on the inner connecting plate 12 in the direction of the other side of the in-line direction X.

Therefore, as shown in FIG. 3, the relative displacement between the pin 21 and the bush 18 in the in-line direction X (direction perpendicular to the axis direction of the pin 21) corresponds to the outer peripheral surface 21 a of the pin 21 and the inner periphery of the bush 18 The amount of the portion worn by the face 18a. At this time, the pin side seal ring 33 will follow the pin 21 and the bush side seal ring 34 will follow the bush 18. Therefore, the portion worn by the outer circumferential surface 21 a of the pin 21 and the inner circumferential surface 18 a of the bush 18 causes the position between the pin side seal ring 33 and the bush side seal ring 34 to be relatively shifted in the in-line direction X.

As a result, the large-diameter O-ring 35, the square-shaped ring 36, and the small-diameter O-ring 37 are subjected to shear forces due to the displacement of the pin-side seal ring 33 and the bush-side seal ring 34, resulting in elastic deformation . At this time, since the pin-side seal ring 33 and the bush-side seal ring 34 are arranged so as not to overlap in the in-line direction X, they hardly interfere with each other.

In addition, since the pin side seal ring 33 and the bush side seal ring 34 do not interfere with the bush 18 and the pin 21, respectively, the tensile load of the sealed chain 11 does not act on the pin side seal ring 33 and the bush On the side seal ring 34. Therefore, even if the seal type chain 11 wears out and extends, the pin-side seal ring 33 and the bush-side seal ring 34 are not damaged.

In addition, as shown in FIG. 4, the seal portion 32 has a structure in which the large-diameter O-ring 35 has a substantially elliptical cross-sectional view formed by the pin-side first concave groove 38 and the bush-side first concave groove 41. The central part of the direction is sandwiched by both. Therefore, when the large-diameter O-ring 35 is worn to reduce its wire diameter (cross-sectional area) from the state shown by the two-dot chain line in FIG. 4 to the state shown by the solid line, the large-diameter O-ring 35 and the pin There may be a gap between the first groove 38 on the side or the first groove 41 on the bush side.

In this state, if a foreign object enters between the first concave groove 38 on the pin side and the first concave groove 41 on the bush side from the outer peripheral side of the large diameter O-ring 35 in the manner shown by the arrow in FIG. 4, the large diameter O The ring 35 is squeezed radially inward by the foreign material. In this way, since the large-diameter O-ring 35 is sandwiched between both ends in the radial direction formed by the first groove 38 on the pin side and the first groove 41 on the bush side, The gap between the large-diameter O-ring 35 and the first concave groove 38 on the pin side and the first concave groove 41 on the bush side disappears. Therefore, even when the large-diameter O-ring 35 is worn and the wire diameter is reduced, the sealing portion 32 can suppress the entry of foreign matter.

However, even when the small-diameter O-ring 37 is worn and the wire diameter is reduced, the sealing portion 32 can suppress the entry of foreign matter in the same manner as the case of the large-diameter O-ring 35 described above.

According to the embodiment detailed above, the following effects can be exerted.

(1) In the sealed chain 11, the seal portion 32 includes an annular pin-side seal ring 33 and an annular bush-side seal ring 34. The annular pin-side seal ring 33 is integrally rotatable with respect to the pin 21 When engaged, the bush side seal ring 34 is joined to the bush 18 so as to be rotatable integrally, and faces the pin side seal ring 33 in the width direction Y which is the axial direction of the pin 21. According to this configuration, when the sealed chain 11 is used for a long period of time, the sliding surface between the pin 21 and the bush 18 wears out and causes the sealed chain 11 to wear and extend, because the pin side seal ring 33 will follow the pin 21 In addition, the bush side seal ring 34 will follow the bush 18, so the pin side seal ring 33 and the bush side seal ring 34 will shift relative positions in the in-line direction X with little interference with each other. At this time, since the pin side seal ring 33 and the bush side seal ring 34 do not interfere with the bush 18 and the pin 21, respectively, the tensile load of the seal type chain 11 does not act on the pin side seal ring 33 and the bush side seal Ring 34. Therefore, it is possible to solve the problem that the pin-side seal ring 33 and the bush-side seal ring 34 may be damaged even if the seal type chain 11 wears out.

(2) In the seal-type chain 11, between the pin-side seal ring 33 and the bush-side seal ring 34, large-diameter O-rings 35 and square-shaped rings 36 having different outer diameters are arranged in the radial direction. And small diameter O-ring 37. According to this configuration, the sealing performance of the sealing portion 32 can be improved.

(3) In the sealed chain 11, the large-diameter O-ring 35 is sandwiched by both the central portion in the radial direction formed by the first groove 38 on the pin side and the first groove 41 on the bush side, the square ring 36 is sandwiched by the second concave groove 39 on the pin side and the second concave groove 42 on the bush side, and the small-diameter O-ring 37 is formed at the center in the radial direction formed by the third concave groove 40 on the pin side and the bush groove 43 Between the two. According to this configuration, the individual positions of the large-diameter O-ring 35, the square ring 36, and the small-diameter O-ring 37 can be determined, while improving the sealability of the seal portion 32.

(4) In the sealed chain 11, the first concave groove 38 on the pin side and the first concave groove 41 on the bush side have the deepest depths at the central portion in the radial direction, and the depths at both ends in the radial direction become shallower. According to this configuration, when the large-diameter O-ring 35 sandwiched by both the pin-side first groove 38 and the bush-side first groove 41 in the radial center is abraded to make the wire diameter (cross-sectional area ) When it becomes smaller, a gap occurs between the large-diameter O-ring 35 and the first groove 38 on the pin side or the first groove 41 on the bush side. In this state, if a foreign object enters between the outer circumferential side of the large-diameter O-ring 35 and the first concave groove 38 on the pin side and the first concave groove 41 on the bush side, the large-diameter O-ring 35 will be moved toward the diameter by the foreign body. Squeeze the inside of the direction. In this way, since the large-diameter O-ring 35 is sandwiched by both the radially inner ends of the pin-side first groove 38 and the bush-side first groove 41, the large-diameter O The gap between the ring 35 and the first groove 38 on the pin side and the first groove 41 on the bush side disappears. Therefore, even when the large-diameter O-ring 35 is worn to reduce the wire diameter, the entry of foreign matter can be suppressed.

(5) In the sealed chain 11, the third groove 40 on the pin side and the groove 43 on the bush side have the deepest depths in the central portion in the radial direction, and the depths at both end portions in the radial direction become shallower. According to this configuration, when the small-diameter O-ring 37 sandwiched by both the pin-side third groove 40 and the bush groove 43 in the radial center is abraded, the wire diameter (cross-sectional area) becomes small As a result, a gap occurs between the small-diameter O-ring 37 and the third groove 40 on the pin side or the groove 43 on the bush. In this state, if a foreign object enters from the outer peripheral side of the small-diameter O-ring 37 to between the pin-side third groove 40 and the bush groove 43, the small-diameter O-ring 37 will be squeezed inward in the radial direction by the foreign body Pressure. In this way, since the small-diameter O-ring 37 is sandwiched by both the radially inner ends of the pin-side third groove 40 and the bush groove 43, the small-diameter O-ring 37 The gap between the pin-side third groove 40 and the bush groove 43 disappears. Therefore, even when the small-diameter O-ring 37 is worn to reduce the wire diameter, the entry of foreign matter can be suppressed.

(Example of change)

However, the above embodiment can also be changed as follows.

The first concave groove 38 on the pin side and the first concave groove 41 on the bush side can also be formed in a semicircular cross-sectional view along the cross-sectional shape of the large-diameter O-ring 35.

The third groove 40 on the pin side and the groove 43 on the bush can be formed into a semicircular cross-sectional view along the cross-sectional shape of the small-diameter O-ring 37.

It is also possible to omit any one of the first groove 38 on the pin side and the first groove 41 on the bush side.

It is also possible to omit any one of the pin-side third groove 40 and the bush groove 43.

Either the second groove 39 on the pin side or the second groove 42 on the bush side can be omitted.

The square ring 36 and the small-diameter O-ring 37 may be omitted, and only the large-diameter O-ring 35 may be provided. At this time, it is possible to store grease as a lubricant in the space occupied by the two omitted rings.

It is also possible to omit the large-diameter O-ring 35 and the small-diameter O-ring 37 and provide only the square ring 36. At this time, it is possible to store grease as a lubricant in the space occupied by the two omitted rings.

For example, a fiber sealing material using fibers such as nonwoven fabric can be used instead of the square ring 36.

The sealed chain 11 can also be a connecting portion that is curved so that the width of one end side of the opposing two connecting plates in the in-line direction X is narrower than the width of the other side, and the bush 18 and the pin 21 can be connected in a swingable manner. Multiple ones, so-called offset chains.

11‧‧‧sealed chain 12‧‧‧Inner link board 14‧‧‧External link board 18‧‧‧ Bush 21‧‧‧pin 32‧‧‧Seal 33‧‧‧pin side sealing ring 33a, 34a‧‧‧ Opposite 34‧‧‧ Bush side seal ring 35‧‧‧ Large-diameter O-ring as an example of a sealing member 36‧‧‧Square ring as an example of a sealing member 37‧‧‧small diameter O-ring 38‧‧‧The first groove on the pin side as an example of the groove on the pin side 39‧‧‧Second groove on the pin side as an example of the groove on the pin side 41‧‧‧The first concave groove on the bush side as an example of the concave groove on the bush side 42‧‧‧Second groove on the bush side as an example of the groove on the bush side

FIG. 1 is a cross-sectional view showing a part of a sealed chain according to an embodiment. FIG. 2 is an enlarged view of the main part of FIG. 1. Fig. 3 is an enlarged view of a main part showing a state when wear elongation occurs in Fig. 1. 4 is an enlarged view of a main part showing a state when the large-diameter O-ring in FIG. 1 is worn.

11‧‧‧sealed chain

12‧‧‧Inner link board

12b‧‧‧Outer side of inner connecting plate

14‧‧‧External link board

14a‧‧‧Inner side of outer connecting plate

18‧‧‧ Bush

21‧‧‧pin

32‧‧‧Seal

33‧‧‧pin side sealing ring

34‧‧‧ Bush side seal ring

35‧‧‧large diameter O-ring

36‧‧‧square ring

37‧‧‧small diameter O-ring

Claims (4)

A sealed chain with a pair of inner connecting plates, cylindrical bushes, pins, a pair of outer connecting plates, and a ring-shaped sealing portion, A pair of the inner connecting plates are arranged to face and separate from each other, The cylindrical bush penetrates the pair of inner connecting plates, and is joined to the pair of inner connecting plates in a state where both ends protrude from the outer sides of the pair of inner connecting plates, The pin is rotatably inserted into the bush, The pair of outer connecting plates are arranged so as to sandwich the pair of inner connecting plates from the outside, and are respectively joined to both ends of the pin, The ring-shaped sealing portion is arranged so as to surround the pin and the bush between the outer surface of the inner connecting plate and the inner surface of the outer connecting plate, It is characterized by: The sealing portion includes an annular pin-side sealing ring, an annular bushing-side sealing ring, and an annular sealing member, The annular pin-side seal ring is engaged with the pin so as to be able to rotate integrally, The annular bushing-side sealing ring is integrally rotatable with respect to the bushing, and faces the pin-side sealing ring in the axial direction of the pin, The annular sealing member is arranged so as to be sandwiched between the pin-side seal ring and the bush-side seal ring. The sealed chain according to claim 1, wherein, Between the pin-side seal ring and the bush-side seal ring, a plurality of the seal members having different outer diameters are arranged side by side in the radial direction. The sealed chain according to claim 1 or 2, wherein, The pin-side seal ring is formed with an annular pin-side concave groove on the surface opposed to the bush-side seal ring, The bush side seal ring is formed with an annular bush side concave groove on the surface opposite to the pin side seal ring, The sealing member is sandwiched between the pin-side groove and the bush-side groove. The sealed chain according to claim 3, wherein, The groove on the pin side and the groove on the bush side have the deepest depth in the central portion in the radial direction, and the shallower the depth toward the both end portions in the radial direction.

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