CN110454546B

CN110454546B - Sealed chain

Info

Publication number: CN110454546B
Application number: CN201910363354.5A
Authority: CN
Inventors: 阿部勇志
Original assignee: Tsubakimoto Chain Co
Current assignee: Tsubakimoto Chain Co
Priority date: 2018-05-08
Filing date: 2019-04-30
Publication date: 2021-07-16
Anticipated expiration: 2039-04-30
Also published as: CN110454546A; KR102292941B1; TW202004050A; JP6662405B2; JP2019196790A; TWI735870B; KR20190128563A

Abstract

A sealed chain (11) is provided with a pair of inner link plates (12), a bush (18) having both ends protruding from the outer sides of the pair of inner link plates (12) and joined together, a pin (21) inserted into the bush (18), a pair of outer link plates (14) joining both ends of the pin (21) to the outer sides of the pair of inner link plates (12), and an annular seal portion (32) disposed between the outer side surface (12b) of the inner link plate (12) and the inner side surface (14a) of the outer link plate (14). The seal section (32) is provided with a pin-side seal ring (33) that engages with the pin (21), a bush-side seal ring (34) that engages with the bush (18) and faces the pin-side seal ring (33) in the axial direction of the pin (21), and seal members (35, 36) that are disposed between the pin-side seal ring (33) and the bush-side seal ring (34).

Description

Sealed chain

Technical Field

The present invention relates to a sealed chain in which a seal portion is disposed between an outer side surface of an inner link plate and an inner side surface of an outer link plate.

Background

Conventionally, a sealed chain of this type is known, for example, as shown in patent document 1. The seal mechanism of the sealed chain is composed of a steel annular seal carrier member, a 1 st elastic seal ring, a steel seal ring, and a 2 nd elastic seal ring. The 1 st elastic sealing ring is externally embedded on the outer peripheral surface of the bush protruding from the outer side surface part of the inner plate and is arranged between the annular sealing bearing component and the inner plate. The steel seal ring is disposed on the outer peripheral side of the annular seal bearing member and abuts against the outer side surface of the inner plate. The 2 nd elastic seal ring is sandwiched between the inner peripheral surface of the steel seal ring and the outer peripheral surface of the annular seal carrier member.

The annular seal carrier member has a disc-shaped seal carrier portion and a rim-shaped seal carrier portion. The disc-shaped seal bearing part is externally embedded and fixed on the connecting pin, is abutted against the inner side surface of the outer plate and is arranged between the end surface of the bush and the inner side surface of the outer plate. The rim-shaped seal carrier projects toward the inner panel on the outer peripheral side of the disc-shaped seal carrier.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2008-157423

Disclosure of Invention

The subject to be solved by the invention

However, when the seal type chain is elongated by abrasion due to abrasion of the sliding surface between the connecting pin and the bushing in long-term use, the 1 st elastic seal ring is sandwiched between the outer peripheral surface of the bushing and the rim-shaped seal receiving portion of the annular seal receiving member and is worn out because the annular seal receiving member follows the connecting pin. Further, when the sliding surface between the connecting pin and the bush is worn, the bush abuts against the rim-shaped seal receiving portion of the annular seal receiving member, and therefore, a tensile load applied to the seal type chain acts on the rim-shaped seal receiving portion. There is a problem in that the rim-like seal carrier may be broken.

The invention aims to provide a sealed chain, which can prevent a pin side sealing ring and a bush side sealing ring from being damaged even if abrasion and elongation occur.

Means for solving the problems

Means for solving the above problems and the effects thereof are described below.

The sealed chain for solving the problems comprises a pair of inner link plates, a cylindrical bush, a pin, a pair of outer link plates and an annular sealing part; a pair of the inner link plates are disposed so as to face each other and be separated from each other; the cylindrical bushing penetrates the pair of inner link plates and is joined to the pair of inner link plates in a state where both end portions of the cylindrical bushing protrude from outer sides of the pair of inner link plates; the pin is rotatably inserted into the bushing; a pair of outer link plates disposed so as to sandwich the pair of inner link plates from outside, and joined to both end portions of the pin, respectively; the annular seal portion is disposed so as to surround the pin and the bush between an outer side surface of the inner link plate and an inner side surface of the outer link plate; wherein the seal portion includes an annular pin-side seal ring that is joined to the pin so as to be integrally rotatable, an annular bush-side seal ring that is joined to the bush so as to be integrally rotatable and that faces the pin-side seal ring in the axial direction of the pin, and an annular seal member that is disposed so as to be sandwiched between the pin-side seal ring and the bush-side seal ring.

According to this configuration, when wear elongation occurs in which the seal type chain elongates due to wear of the sliding surface between the pin and the bushing in long-term use, the pin-side seal ring follows the pin and the bushing-side seal ring follows the bushing, so that the pin-side seal ring and the bushing-side seal ring are displaced relative to each other in a direction perpendicular to the axial direction of the pin with little interference therebetween. 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 seal type chain does not act on the pin-side seal ring and the bush-side seal ring. Therefore, even if the seal type chain is worn and extended, the pin side seal ring and the bush side seal ring can be prevented from being damaged.

The above-mentioned canned type chain is preferably: a plurality of the seal members having different outer diameters are arranged in a radial direction between the pin-side seal ring and the bush-side seal ring.

According to this configuration, the sealing performance of the sealing portion can be improved.

The above-mentioned canned type chain is preferably: an annular pin-side groove is formed in a surface of the pin-side seal ring facing the bushing-side seal ring, an annular bushing-side groove is formed in a surface of the bushing-side seal ring facing the pin-side seal ring, and the seal member is sandwiched between the pin-side groove and the bushing-side groove.

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

The above-mentioned canned type chain is preferably: the pin-side concave groove and the bush-side concave groove are formed to have the deepest depth at the center portion in the radial direction and the shallower depth toward both end portions in the radial direction.

According to this configuration, when the seal member sandwiched between the center portions of the pin-side groove and the bush-side groove in the radial direction is worn and the sectional area thereof is reduced, a gap is formed between the seal member and the pin-side groove or the bush-side groove. If foreign matter enters between the pin-side groove and the bush-side groove from the outer peripheral side of the seal member in this state, the seal member is pressed radially inward by the foreign matter. In this way, the seal member is sandwiched between the radially inner ends of the pin-side groove and the bush-side groove, and therefore the gap between the seal member and the pin-side groove and the bush-side groove disappears. Therefore, even when the seal member is worn and the sectional area thereof is reduced, the entry of foreign matter can be suppressed.

Effects of the invention

According to the present invention, even if the sealed chain is worn and elongated, the pin-side seal ring and the bush-side seal ring can be prevented from being damaged.

Drawings

Fig. 1 is a sectional view showing a part of a closed type chain according to an embodiment.

Fig. 2 is an enlarged view of a main portion of fig. 1.

Fig. 3 is an enlarged view of a main part showing a state in which wear elongation occurs in fig. 1.

Fig. 4 is an enlarged view of a main portion of fig. 1 showing a state in which the large-diameter O-ring is worn.

Detailed Description

Hereinafter, an embodiment of the sealed chain will be described with reference to the drawings.

As shown in fig. 1, the closed type chain 11 includes a plurality of inner links 13 and a plurality of outer links 15 made of, for example, a steel material. Each inner link 13 has a pair of inner link plates 12 arranged to face each other in the width direction Y and to be spaced apart from each other. Each outer link 15 has a pair of outer link plates 14 arranged to sandwich the pair of inner link plates 12 from the outside in the width direction Y.

The inner link plates 12 of the inner links 13 and the outer link plates 14 of the outer links 15 extend in the vertical row direction X, which is a moving direction in which the seal chain 11 is pulled and moved from one side in the longitudinal direction perpendicular to the width direction Y, to form a substantially rectangular plate shape. The inner link plates 12 and the outer link plates 14 facing each other in the width direction Y are arranged parallel to each other.

Therefore, the sealed chain 11 of the present embodiment is a so-called flat chain. That is, each inner link 13 is configured to: the interval between the pair of inner link plates 12 is equal on one end side and the other end side of the inner link 13 in the straight row direction X; each outer link 15 is configured to: the interval between the pair of outer link plates 14 is equal between one end side and the other end side of the outer link 15 in the straight row direction X.

At both ends of the inner link plates 12 in the row direction X, circular bushing insertion holes 17 are formed to penetrate in the width direction Y, which is the thickness direction of the inner link plates 12. Between a pair of inner link plates 12 facing each other in the

inner link

13, 2 cylindrical bushes 18 are assembled, and the cylindrical bushes 18 maintain the distance between the pair of inner link plates 12.

Both end portions of the bushing 18 are fitted (joined) to the bushing insertion holes 17 of the pair of inner link plates 12, respectively, so as not to rotate. At this time, the front end portions of the opposite end portions of the bushing 18 protrude outward in the width direction Y from the pair of inner link plates 12. That is, the bushing 18 penetrates a pair of the inner link plates 12 at both end portions. The bush 18 rotatably supports the roller 19 by being inserted into the cylindrical roller 19. That is, the bush 18 is movably fitted to the roller 19.

At both ends of the outer link plate 14 in the in-line direction X, circular pin insertion holes 22 are formed to penetrate in the width direction Y, which is the thickness direction of the outer link plate 14. 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 tip of the pin 21. The hole 23 is inserted with a separation preventing pin 24 for preventing the pin 21 from separating from the pin insertion hole 22. The distal end portion of the anti-slip pin 24 is bent so as not to slip out of the hole 23.

The pair of outer link plates 14 of the outer link 15 are rotatably connected to the inner link plates 12 of the inner link 13 via pins 21 in a state of being disposed so as to sandwich the pair of inner link plates 12 of the inner link 13 from the outside, and a bushing 18 is assembled between the pair of inner link plates 12. At this time, the pin 21 is inserted rotatably into the bushing 18 assembled between the pair of inner link plates 12 of the inner link 13 in the intermediate portion other than the both end portions, and the both end portions are fitted (joined) into the pin insertion holes 22 of the pair of outer link plates 14 of the outer link 15 so as to be incapable of rotating, respectively.

Therefore, the two end portions of the pin 21 penetrate the pair of outer link plates 14, respectively, and the inner link plates 12 of the inner links 13 and the outer link plates 14 of the outer links 15 adjacent in the straight row direction X are rotatably connected to each other by the pin 21 and the bushing 18 at the end portions in the straight row direction X.

A circular recess 26 is formed in the base end surface 25 of the pin 21. A linearly extending communication path 27 is formed in the pin 21 from the center of the bottom surface of the recess 26 to the center of the pin 21 in the width direction Y as the axial direction. A grease nozzle (nipple)28 for injecting grease into the communication passage 27 is attached to an opening of the communication passage 27 on the side of the recess 26.

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 an end of the communication path 27 on the opposite side to the recess 26 side via a pin hole 30. Therefore, the communication path 27 communicates the grease nozzle 28 with the pin hole 30.

A bottomed circular box-shaped cap 31 made of a flexible material such as rubber is detachably attached to the recess 26 of the pin 21. In a state where the cap 31 is fitted to the concave portion 26 of the pin 21, the cap 31 covers the grease nozzle 28. A fine hole 31a is formed through the center of the bottom wall of the cap 31.

Grease as a lubricant is disposed between the outer peripheral surface 21a of the pin 21 and the inner peripheral surface 18a of the bush 18. Grease can be replenished between the outer peripheral surface 21a of the pin 21 and the inner peripheral surface 18a of the bush 18 from the grease nozzle 28 through the communication passage 27, the pin hole 30, and the groove 29. An annular seal portion 32 is disposed between the outer side surface 12b of the inner link plate 12 and the inner side surface 14a of the outer link plate 14. The annular seal portion 32 is disposed so as to surround the pin 21 and the bush 18.

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

As shown in fig. 1 and 2, the seal portion 32 includes a metal pin-side seal ring 33 having a circular plate shape, a metal bush-side seal ring 34 having a circular plate shape, a large-diameter O-ring 35 as an example of an annular seal 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 externally fitted (joined) to the pin 21 so as to be rotatable integrally with the pin 21, and an outer surface of the pin side seal ring 33 in the width direction Y contacts the inner surface 14a of the outer link plate 14. The bush-side seal ring 34 is externally fitted (joined) to the bush 18 so as to be rotatable integrally with the bush 1, and the bush-side seal ring 34 faces the pin-side seal ring 33 in the width direction Y in the axial direction of the pin 21. The inner surface of the bushing-side seal ring 34 in the width direction Y contacts the outer side surface 12b of the inner link plate 12. The bush-side seal ring 34 and the pin-side seal ring 33 do not overlap in the radial direction and the straight-line direction X.

The large-diameter O-ring 35 and the small-diameter O-ring 37 are circular in cross-sectional view, and the square-shaped ring 36 is rectangular in cross-sectional view. The large-diameter O-ring 35 and the square ring 36 are disposed 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 disposed 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-shaped ring 36, and the small-diameter O-ring 37 are all made of a flexible material such as an elastomer. Of the large-diameter O-ring 35, the square-shaped 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 large-diameter O-rings 35, the square-shaped rings 36, and the small-diameter O-rings 37 have different outer diameters and are arranged in a radial direction. Grease as a lubricant is sufficiently applied to the large-diameter O-ring 35, the square-shaped ring 36, and the small-diameter O-ring 37.

A pin-side 1 st groove 38, which is an example of an annular pin-side groove, and a pin-side 2 nd groove 39, which is an example of an annular pin-side groove, are formed in the pin-side seal ring 33 at positions corresponding to the large-diameter O-ring 35 and the square ring 36 on the facing surface 33a facing the bush-side seal ring 34. The pin-side 1 st groove 38 has a substantially semi-elliptical shape in cross section, and the bottom surface thereof is pressed against the large-diameter O-ring 35. The pin-side first groove 38 has the deepest depth at the center portion in the radial direction of the pin-side seal ring 33 and the shallower depth toward both end portions in the radial direction. The pin-side 2 nd groove 39 is formed in a substantially U shape in a cross-sectional view, and is fitted to a position of about half in the thickness direction (width direction Y) of the square ring 36.

A pin-side 3 rd groove 40 is formed in a facing surface 33b of the pin-side seal ring 33 facing the end surface 18b of the bush 18 at a position corresponding to the small-diameter O-ring 37. The pin-side 3 rd groove 40 has a substantially semi-elliptical shape in cross section, and the bottom surface thereof is pressed against the small-diameter O-ring 37. The pin-side 3 rd recessed groove 40 has the deepest depth at the center portion in the radial direction of the pin-side seal ring 33 and the shallower depth toward both end portions in the radial direction.

A bush-side 1 st groove 41 as an example of an annular bush-side groove and a bush-side 2 nd groove 42 as an example of an annular bush-side groove are formed in the facing surface 34a of the bush-side seal ring 34 facing the pin-side seal ring 33, respectively. The liner-side 1 st groove 41 has a substantially semi-elliptical shape in cross section, and the bottom surface thereof is pressed against the large-diameter O-ring 35. The liner-side first groove 41 has the deepest depth at the center portion in the radial direction of the liner-side seal ring 34 and the shallower depth toward both end portions in the radial direction. The liner-side No. 2 groove 42 is substantially L-shaped in cross-sectional view, and is fitted to a portion of the square ring 36 which is approximately half in the thickness direction (width direction Y). At this time, the inner peripheral surface 36a of the square ring 36 contacts the outer peripheral surface 18c of the bush 18.

An annular bush groove 43 is formed in the end surface 18b 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 the bottom surface thereof is pressed against the small-diameter O-ring 37. The bushing groove 43 has the deepest depth at the center portion in the radial direction of the bushing side seal ring 34 and the shallower depth toward both end portions in the radial direction.

The large-diameter O-ring 35 is sandwiched between the pin-side 1 st groove 38 and the bush-side 1 st groove 41 at the center in the radial direction. The pin-side 1 st groove 38 and the bush-side 1 st groove 41 are formed in shapes that coincide with each other. The square ring 36 is held between the pin-side 2 nd groove 39 and the bush-side 2 nd groove 42. The pin-side 2 nd groove 39 and the groove formed by the bush-side 2 nd groove 42 and the outer peripheral surface 18c of the bush 18 are formed in shapes that almost match each other.

The small-diameter O-ring 37 is sandwiched between the pin-side 3 rd groove 40 and the bush groove 43 at the center in the radial direction. The pin-side 3 rd groove 40 and the bush groove 43 are formed in shapes that coincide with each other. A slight gap S1 is formed between the facing surface 33a of the pin-side seal ring 33 that faces the bush-side seal ring 34 and the facing surface 34a of the bush-side seal ring 34 that faces the pin-side seal ring 33. A slight gap S2 is formed between the facing surface 33b of the pin-side seal ring 33 facing the end surface 18b of the bush 18 and the end surface 18b of the bush 18. The size of the space S1 is almost the same as the size of the space S2.

Next, the operation of the seal type chain 11 will be described.

When one sprocket is rotated in a state where the endless sealed chain 11 is meshed with a pair of sprockets (not shown) disposed apart from each other in a wound manner, the sealed chain 11 moves around the pair of sprockets. When the sealed chain 11 is used for a long period of time in this manner, abrasion occurs between the outer circumferential surface 21a of the pin 21 and the inner circumferential surface 18a of the bushing 18.

Thus, the seal type chain 11 is elongated, that is, wear elongation occurs, as the gap between the outer peripheral surface 21a of the pin 21 and the inner peripheral surface 18a of the bushing 18 becomes larger. When the sealed chain 11 is worn and elongated, a tension load applied to the sealed chain 11 acts in a direction opposite to each other on the outer link plates 14 and the inner link plates 12. Specifically, the tension load of the closed chain 11 acts in one direction of the outer link plates 14 in the vertical row direction X and acts in the other direction of the inner link plates 12 in the vertical row direction X.

Therefore, as shown in fig. 3, the positions of the pin 21 and the bush 18 are shifted relatively in the inline direction X (direction perpendicular to the axial direction of the pin 21) by an amount corresponding to the portion worn by the outer peripheral surface 21a of the pin 21 and the inner peripheral surface 18a of the bush 18. At this time, the pin side seal ring 33 follows the pin 21, and the bush side seal ring 34 follows the bush 18. Therefore, the positions of the pin-side seal ring 33 and the bush-side seal ring 34 are shifted in the inline direction X by an amount corresponding to the portion worn by the outer peripheral surface 21a of the pin 21 and the inner peripheral surface 18a of the bush 18.

In this way, the large-diameter O-ring 35, the square-shaped ring 36, and the small-diameter O-ring 37 undergo elastic deformation due to shear force accompanying the positional displacement between the pin-side seal ring 33 and the bush-side seal ring 34. At this time, the pin-side seal ring 33 and the bush-side seal ring 34 are arranged so as not to overlap in the inline direction X, and therefore 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 bushing 18 and the pin 21, respectively, the tensile load of the seal chain 11 does not act on the pin-side seal ring 33 and the bush-side seal ring 34. Therefore, even if the seal type chain 11 is worn and extended, the pin side seal ring 33 and the bush side seal ring 34 are not damaged.

Further, as shown in fig. 4, the seal portion 32 has the following configuration: the large-diameter O-ring 35 is sandwiched between the respective radially central portions of the pin-side 1 st groove 38 and the bush-side 1 st groove 41, which have a substantially elliptical shape in cross-sectional view. Therefore, when the large-diameter O-ring 35 is worn and the wire diameter (cross-sectional area) thereof is reduced from the state shown by the two-dot chain line in fig. 4 to the state shown by the solid line, a gap is formed between the large-diameter O-ring 35 and the pin-side 1 st groove 38 or the bush-side 1 st groove 41.

In this state, if foreign matter enters between the pin-side 1 st groove 38 and the bush-side 1 st groove 41 from the outer peripheral side of the large-diameter O-ring 35 as indicated by an arrow in fig. 4, the large-diameter O-ring 35 is pressed inward in the radial direction by the foreign matter. Thus, the large-diameter O-ring 35 is sandwiched between the radially inner ends of the pin-side 1 st groove 38 and the bush-side 1 st groove 41, and hence the gap between the large-diameter O-ring 35 and the pin-side 1 st groove 38 and the bush-side 1 st groove 41 disappears. Therefore, the seal portion 32 can suppress the entry of foreign matter even when the large-diameter O-ring 35 is worn and the wire diameter is reduced.

Even when the small-diameter O-ring 37 is worn and the wire diameter is reduced, the seal portion 32 can suppress the entry of foreign matter as in the case of the large-diameter O-ring 35.

The embodiments described in detail above can exhibit the following effects.

(1) In the sealed chain 11, the seal portion 32 includes an annular pin-side seal ring 33 and an annular bushing-side seal ring 34, the annular pin-side seal ring 33 is joined to the pin 21 so as to be rotatable integrally with the pin 21, and the bushing-side seal ring 34 is joined to the bushing 18 so as to be rotatable integrally with the bushing 18, 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 sliding surface between the pin 21 and the bushing 18 wears due to long-term use of the sealed chain 11 and wear elongation of the sealed chain 11 extending occurs, the pin-side seal ring 33 follows the pin 21 and the bushing-side seal ring 34 follows the bushing 18, so that the pin-side seal ring 33 and the bushing-side seal ring 34 are displaced relative to each other in the straight line direction X with little interference therebetween. At this time, since the pin-side seal ring 33 and the bush-side seal ring 34 do not interfere with the bushing 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, even if the seal type chain 11 is worn and elongated, the possibility of damage to the pin side seal ring 33 and the bush side seal ring 34 can be eliminated.

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

(3) In the closed chain 11, the large-diameter O-ring 35 is held between the pin-side 1 st groove 38 and the bush-side 1 st groove 41 at the center portion in the radial direction, the square-shaped ring 36 is held between the pin-side 2 nd groove 39 and the bush-side 2 nd groove 42, and the small-diameter O-ring 37 is held between the pin-side 3 rd groove 40 and the bush groove 43 at the center portion in the radial direction. With this configuration, the positions of the large-diameter O-ring 35, the square-shaped ring 36, and the small-diameter O-ring 37 can be determined, and the sealing performance of the seal portion 32 can be improved.

(4) In the sealed chain 11, the pin-side 1 st groove 38 and the bushing-side 1 st groove 41 have the deepest depth at the center portion in the radial direction and have the shallower depth toward both end portions in the radial direction. According to this configuration, when the large-diameter O-ring 35 sandwiched between the center portions of the pin-side 1 st groove 38 and the bush-side 1 st groove 41 in the radial direction is worn and the wire diameter (cross-sectional area) is reduced, a gap is formed between the large-diameter O-ring 35 and the pin-side 1 st groove 38 or the bush-side 1 st groove 41. If foreign matter enters between the pin-side 1 st groove 38 and the bush-side 1 st groove 41 from the outer peripheral side of the large-diameter O-ring 35 in this state, the large-diameter O-ring 35 is pressed radially inward by the foreign matter. Thus, the large-diameter O-ring 35 is sandwiched between the pin-side 1 st groove 38 and the bush-side 1 st groove 41 at the radially inner ends thereof, and hence the gap between the large-diameter O-ring 35 and the pin-side 1 st groove 38 and the bush-side 1 st groove 41 disappears. Therefore, even when the large-diameter O-ring 35 is worn and the wire diameter thereof is reduced, entry of foreign matter can be suppressed.

(5) In the closed chain 11, the pin-side 3 rd groove 40 and the bushing groove 43 have the deepest depth at the center portion in the radial direction and the shallower depth toward both end portions in the radial direction. According to this configuration, when the small-diameter O-ring 37 sandwiched between the pin-side 3 rd groove 40 and the bush groove 43 at the center portion in the radial direction is worn and the linear diameter (cross-sectional area) thereof is reduced, a gap is formed between the small-diameter O-ring 37 and the pin-side 3 rd groove 40 or the bush groove 43. If foreign matter enters between the pin-side 3 rd recessed groove 40 and the bush recessed groove 43 from the outer peripheral side of the small-diameter O-ring 37 in this state, the small-diameter O-ring 37 is pressed inward in the radial direction by the foreign matter. Thus, the small-diameter O-ring 37 is sandwiched between the pin-side 3 rd groove 40 and the bush groove 43 at the inner ends in the radial direction, and hence the gap between the small-diameter O-ring 37 and the pin-side 3 rd groove 40 and the bush groove 43 disappears. Therefore, even when the small-diameter O-ring 37 is worn and the wire diameter is reduced, entry of foreign matter can be suppressed.

(modification example)

However, the above embodiment can be modified as follows.

The pin-side 1 st groove 38 and the bush-side 1 st groove 41 may be formed in a semicircular shape in cross section along the cross section of the large-diameter O-ring 35.

The pin-side 3 rd groove 40 and the bush groove 43 may be formed in a semicircular shape in cross section along the cross section of the small-diameter O-ring 37.

Any of the pin-side 1 st groove 38 and the bush-side 1 st groove 41 may be omitted.

Either the pin-side 3 rd groove 40 or the bush groove 43 can be omitted.

Any of the pin-side 2 nd groove 39 and the bush-side 2 nd groove 42 may be omitted.

Instead of the square ring 36 and the small-diameter O-ring 37, only the large-diameter O-ring 35 may be provided. In this case, grease as a lubricant can be stored in the space occupied by the omitted 2 rings.

Instead of the large-diameter O-ring 35 and the small-diameter O-ring 37, only the square ring 36 may be provided. In this case, grease as a lubricant can be stored in the space occupied by the omitted 2 rings.

Instead of the square ring 36, a fiber sealing material using fibers such as nonwoven fabric may be used.

The sealed chain 11 may be a so-called offset chain in which a plurality of links bent so that the width of one end side of 2 facing link plates in the tandem direction X is narrower than the width of the other end side are rotatably connected by bushings 18 and pins 21.

Description of the reference numerals

11 sealing type chains; 12 inner link plates; 14 outer link plates; 18a bushing; 21, a pin; 32 a sealing part; 33a pin-side seal ring; 33a, 34a facing surfaces; 34a liner side seal ring; 35 a large-diameter O-ring as an example of the sealing member; 36a square ring as an example of the sealing member; 37 minor-diameter O-rings; 38 a pin-side 1 st groove as an example of the pin-side groove; 39 a pin-side 2 nd groove as an example of the pin-side groove; 41 a bush-side 1 st groove as an example of the bush-side groove; 42 a bush-side No. 2 groove as an example of the bush-side groove.

Claims

1. A sealed chain includes a pair of inner link plates, a cylindrical bushing, a pin, a pair of outer link plates, and an annular seal portion,

a pair of the inner link plates are disposed in a mutually opposing and spaced-apart manner,

the cylindrical bushing penetrates the pair of inner link plates and is joined to the pair of inner link plates in a state where both end portions thereof protrude from outer sides of the pair of inner link plates,

the pin is rotatably inserted into the bushing,

a pair of the outer link plates are disposed so as to sandwich a pair of the inner link plates from outside, and are respectively joined to both end portions of the pin,

the annular seal portion is disposed so as to surround the pin and the bush between an outer side surface of the inner link plate and an inner side surface of the outer link plate,

the sealed chain is characterized in that:

the seal portion includes an annular pin-side seal ring, an annular bushing-side seal ring, and an annular seal member,

the annular pin-side seal ring is engaged with the pin so as to be rotatable integrally,

the annular bush-side seal ring is joined to the bush so as to be rotatable integrally therewith and opposes the pin-side seal ring in the axial direction of the pin,

the annular seal member is disposed so as to be sandwiched between the pin-side seal ring and the bush-side seal ring,

the sealing member is an O-ring,

an annular pin-side groove is formed in a surface of the pin-side seal ring facing the bush-side seal ring,

an annular bushing-side groove is formed in a surface of the bushing-side seal ring facing the pin-side seal ring,

the O-ring is sandwiched by the pin-side groove and the bush-side groove,

the pin-side concave groove and the bush-side concave groove are formed to have the deepest depth at the center portion in the radial direction and the shallower depth toward both end portions in the radial direction.

2. The sealed chain according to claim 1,

the seal portion further includes an annular seal member arranged to be sandwiched between the pin-side seal ring and an end surface of the bushing, and having a circular shape in a cross-sectional view.

3. The closed type chain according to claim 2,

the seal portion further includes an annular seal member arranged to be sandwiched between the pin-side seal ring and the bush-side seal ring and having a rectangular shape in a cross-sectional view.