JP5415316B2 - Seal chain - Google Patents

Description

  The present invention relates to a seal chain used as a drive chain for a transport machine such as a motorcycle or a general industrial machine, or as a transport chain for a conveyor or the like, and more specifically, in a natural state and having a substantially plus (10) cross section. The present invention relates to a seal chain using a seal member.

  The present applicant uses a ring-shaped seal member having a lip portion that hangs down in the inner diameter direction in a natural state, and the seal member is interposed between the inner link plate and the outer link plate so as to be twisted with the lip portion as a fulcrum. Has devised a manufacturing method of a seal chain to be attached to the hood (see Patent Document 1). When the manufacturing method is shown in FIG. 9, first, as shown in FIG. 9A, the first lip portion 3 a of the seal member 3 is positioned between the tip of the bush protruding portion 7 a and the outer link plate 8. Then, the outer link plate 8 is temporarily assembled to the pin 2 in a state where it is separated from the seal member 3 by a predetermined distance c. In this state, for example, it is immersed in a fluid grease (lubricant), and the grease is supplied between the pin 2 and the bush 7 in the seal member 3. Then, as shown in FIG. 9B, the outer link plate 8 is press-fitted in the arrow direction. At this time, as the outer link plate 8 is press-fitted, the plate 8 comes into contact with the seal member 3, and the outer lip portion 3 a of the seal member 3 is in contact with the tip of the protruding portion 7 a of the bush 7. When the link plate 8 moves in the direction of the arrow, as shown in FIG. 9C, the seal member 3 is twisted as indicated by the arrow with the corresponding contact portion as a fulcrum.

  As a result, the seal member is positioned such that the first lip portion 3a is in contact with the outer peripheral surface of the distal end of the bushing projection 7a and the outer link plate 8, and the third lip portion 3c is in contact with the outer link plate 8. Further, the fourth lip portion 3d abuts on the inner link plate 6 and the second lip portion 3b abuts on the inner link plate 6, and the seal member 3 becomes a seal member having a substantially X-shaped cross section. It is sandwiched between the link plates 6 and 8. The seal member 3 as described above is mounted on both the left and right sides of the bush 7, and the tip of the pin 2 is crimped to prevent the outer link plate 8 from being pulled out, thereby completing the seal chain 1.

FIG. 10 is a cross-sectional view showing the sealing member 3 in a natural state, and (a) and (b) are different from each other. Figure 10 seal member 3 in ₁ (a), the central base portion 3 _{1 e} radially inward wide semicircular first extending downward (right side in FIG. 10) of the lip portion 3 _{1 a,} the outer at the same width The second lip portion 3 ₁ b extending in the radial direction (left side in FIG. 10), and the left and right directions from the first and second lip portions 3 ₁ a and 3 ₁ b (direction perpendicular to the radial direction, FIG. 10) The third and fourth lip portions 3 ₁ c and 3 ₁ d extending in the vertical direction) are formed in a substantially cross-shaped cross section as a whole. The tip portion of the first lip portion 3 _{1 a} is composed of rounded shape r _{1 a} made of semicircular connecting portion of each lip is constituted by a predetermined radius shape r.

10 sealing member 3 ₂ (b) has a first lip portion 3 _{2 a} of substantially circular cross section extending downward in the inner diameter direction of the center base portion 3 _{2 e,} respectively same width in the outer diameter direction and the lateral direction The second lip portion 3 ₂ b, the third lip portion 3 ₂ c, and the fourth lip portion 3 ₂ d are formed in a substantially cross-shaped cross section as a whole. Further, the sealing member _{3 2,} the first lip portion _{3 2} a is composed of rounded shape _{r 2} a. The connecting portion between the first lip portion 3 ₂ a and the third and fourth lip portions 3 ₂ c and 3 ₂ d is formed by a rounded r-shape r ′, and the second lip A connecting portion between the portion 3 ₂ b and the third and fourth lip portions 3 ₂ c and 3 ₂ d is formed in a predetermined round shape r. In the case of the illustrated example, the width of the base end portion of the first lip portion 3 ₂ a and the width of the _second lip portion 3 ₂ b is the width of the third and fourth lip portions 3 ₂ c and 3 ₂ d. Is almost the same as or slightly larger.

Japanese Patent Publication No. 6-48038

Incidentally, the seal chain 1, for sandwiching the sealing member 3 ₁ or 3 ₂ between the inner link plates 6 and the outer link plate 8, as compared with the sealless chain without seals, inner link plates 6 and the outer link plate 8 It is necessary to take a large clearance. Therefore, the above-mentioned seal chain is easily bent due to the length of the large clearance, and even if the chain uses the same pin diameter and the same link plate, the tensile strength is smaller than that of the non-seal chain.

  In order to increase the strength of the seal chain, it is necessary to reduce the clearance between the inner link plate 6 and the outer link plate 8. However, if the cross-sectional area of the seal member is reduced, the contact pressure to the plate of the lip portion is reduced. Lubricant is likely to leak. As a result, the wear resistance of the chain is lowered and the life of the chain is shortened.

  On the other hand, if the cross-sectional area of the seal member is too large for the clearance between the inner link plate 6 and the outer link plate 8, the seal member is excessively crushed and the contact pressure of the lip portion against the plate becomes too high. End up. Normally, the seal member is in sliding contact with the outer link plate 8, but if the contact pressure at this contact portion is high, the flexibility of the chain deteriorates and the seal member is likely to be worn early. And it becomes easy to leak a lubricant, and the lifetime of a chain will become short.

  On the other hand, as shown in FIG. 11, the seal chain 1 may be driven in an in-use state so as to be slanted (offset state). For example, in a motorcycle, a chain is passed between the sprocket on the engine side and the sprocket on the wheel side, but these sprockets are offset by the load acting on the manufacturing error or turning, and the chain passed between the sprockets is slanted. It may become. At this time, as shown in FIG. 11, the outer link plate 8 is inclined with respect to the inner link plate 6, and the amount of crushing of the seal member 3 sandwiched between both the plates 6, 8 (seal crushing amount) Becomes uneven.

  In other words, the seal crushing amount is increased in part, while the seal crushing amount is decreased in other portions. Further, the contact pressure between the lip portion of the seal member and the plate also becomes non-uniform, so that the lubricant is liable to leak or the seal member is likely to be worn. Also, depending on the shape of the seal member, stress concentration occurs at the connecting portion of each lip portion when the seal member is crushed, and the seal member is likely to be damaged early, such as cracks, or permanent at the stress concentration portion. As the distortion progresses, the followability deteriorates and the lubricating oil easily leaks.

  Considering the above points, the seal member is sized so as not to be crushed even if the clearance between the inner link plate 6 and the outer link plate 8 is small, and the contact pressure between the lip portion and the plate is appropriately secured. Even if the seal chain is slanted and the amount of crushing of the seal becomes uneven, the non-uniformity of the contact pressure can be suppressed. It is preferable to reduce stress concentration.

Of the conventional structure shown in FIG. 10 described above, in the case of the structure shown in FIG. 10A, the first and second lip portions 3 ₁ a and 3 ₁ b have a large width, so the clearance is reduced. Even if the size is reduced correspondingly, it is considered that the contact pressure is easily secured. However, since the first lip portion 3 ₁ a and the second lip portion 3 ₁ b are formed to extend in the radial direction with the same width, the seal chain is in an offset state and the amount of seal crushing is changed. In this case, it is difficult to cope with this change, and it is considered that the difference in contact pressure between the portion where the contact pressure increases and the portion where the contact pressure decreases becomes large.

In the case of the structure shown in FIG. 10B, the base end portion of the first lip portion 3 ₂ a and the width of the _second lip portion 3 ₂ b are the third and fourth lip portions having a small width. Since the widths of 3 ₂ c and 3 ₂ d are substantially the same, when the size is reduced in response to the reduction in the clearance, the tensile force against the plate is increased even in a normal state where no offset occurs. It is difficult to secure and it is considered difficult to secure the contact pressure. That is, even if the first lip portion 3 ₂ a having a large width in the radial direction is sufficiently in contact with the outer link plate 8, the second lip portion 3 ₂ b having a small width dimension contacts the inner link plate 6. As a result, the tension force between the inner link plate 6 and the outer link plate 8 by the seal member cannot be sufficiently increased. For this reason, it is considered that the contact pressure between the first lip portion 3 ₂ a and the outer link plate 8 cannot be sufficiently secured.

Also in the case of the shape of FIG. 10B, the second lip portion 3 ₂ b is formed to extend in the radial direction with the same width, so that the seal chain is in an offset state and the amount of crushing of the seal is reduced. In the case of a change, it is considered that the difference in contact pressure between the portion where the contact pressure is large and the portion where the contact pressure is small is difficult to cope with this change. Regarding the first lip portion 3 ₂ a, since the width of the radial intermediate portion is large and the width of the base end portion is small, the change in the amount of seal crushing can be absorbed somewhat at the base end portion. It is considered that the difference in contact pressure due to offset can be made smaller than the shape of a ).

However, unless the R shape r ′ of the base end portion is increased, stress concentration occurs at the time of deformation, and the seal member is likely to be damaged or the followability of the seal member is likely to be deteriorated. When the rounded shape r ′ is increased, the difference in width between the radial base end portion and the intermediate portion of the first lip portion 3 ₂ a is reduced, and the width of the intermediate portion is reduced. The smaller the width of the intermediate portion, force strut of the first lip portion 3 _{2 a} is lowered, the contact pressure becomes low. On the other hand, if the length in the radial direction of the first lip portion 3 ₂ a is increased, the difference in width between the radial base end portion and the intermediate portion can be increased while increasing the round shape r ′. However, since this length dimension is restricted due to the relationship of assembling between the narrow plates 6 and 8, it is difficult to increase the round shape r ′ in the case of the shape of FIG.

  In the present invention, in order to increase the tensile strength of the chain, the contact pressure between the lip portion and the plate is reduced even if the size of the seal member is reduced in response to the reduction in the clearance between the inner link plate and the outer link plate. Even when the seal chain is slanted over and the amount of crushing of the seal becomes uneven, the contact pressure can be prevented from being uneven. It is an object of the present invention to provide a seal chain that can relieve stress concentration in a connection portion.

In order to solve the above-mentioned problems, the present invention has a structure in which the bush (17) is partially protruded from the inner link plate (16) so as to surround the protruding portion (17a) and the inner link plate (16) and the outer link plate (18). The ring-shaped sealing member (13) is disposed so as to be sandwiched between
The seal member (13) has a cross-section in a natural state having a cross shape, a central base (13e), a first lip portion (13a) extending from the central base (13e) in an inner diameter direction, and the central base ( 13e) a second lip portion (13b) extending in the outer diameter direction, and third and fourth lip portions (13c) (13c) extending in the left-right direction (vertical direction in FIGS. 2 and 3 ) from the central base portion (13e) . 13d)
With the first lip portion (13a) disposed between the front end of the bushing projection (17a) and the outer link plate (18), the outer link plate (18) is moved to the inner link plate (16). The seal member (13) is twisted by a rotational moment based on contact with the projection (17a) of the bush , and is deformed into a substantially X-shaped cross section. The present invention relates to a seal chain (11) sandwiched between (16) and the outer link plate (18).

And in the natural state, the first lip portion (13a) has a round cross section formed by a rounded surface (13g) or a curved surface close thereto or a shape close thereto,
In the first and second lip portions (13a) and (13b), the width (A) of the radial intermediate portion is larger than the width (B) of the third and fourth lip portions (13c) and (13d), respectively. Larger in width and narrower than the intermediate portion in the radial direction, the left and right side surfaces of the first and second lip portions (13a) and (13b), and the third and fourth lips. It has a constriction part (13f) which makes the both ends of a diameter direction of a part (13c) (13d) continue by a curved concave surface (13h), respectively.

  The first lip portion (13a) is not limited to a circular cross section, and includes a shape close to a circle such as an ellipse, an ellipse, or an oval. Further, the second lip portion (13b) can also have a circular cross-section or a shape close to the same as the first lip portion (13a).

  Preferably, in the natural state, the first and second lip portions (13a) and (13b) each have a width (C) of the radial base end portion that is the third and fourth lip portions (13c) ( It is larger than the width (B) of 13d).

  Preferably, in the natural state, the first and second lip portions (13a) and (13b) are formed symmetrically with respect to a center line (OO) perpendicular to the radial direction in the cross section of the seal member (13). Is done.

  Preferably, in the natural state, the width (A) of the largest portion of the first and second lip portions (13a) and (13b) is the third and fourth lip portions (13c) and (13d). The width (B) is 1.5 to 1.7 times.

Preferably, in a natural state, the curved concave surface (13 h ) of the constricted portion (13f) of the first and second lip portions (13a) (13b) is formed in the left-right direction of the seal member (13) (FIG. 2, 3 ) and a radius of curvature (r ₂ ) of 0.12 times or more. In addition, the curvature radius (r ₂ ) of the curved concave surface (13 h ) is preferably 0.2 times or less, more preferably 0.15 times or less the horizontal dimension of the seal member.

  In addition, although the code | symbol in the said parenthesis is for contrast with drawing, it has no influence on a claim by this.

According to the first aspect of the present invention, the first and second lip portions are in a state in which the seal member is crushed because the radial intermediate width is larger than the third and fourth lip widths. Thus, the first and second lip portions are sufficiently stretched against the plate, and the contact pressure between the lip portion and the plate can be secured. Further , the radial base end portion is narrower than the radial intermediate portion, and both the left and right side surfaces of the first and second lip portions and the radial end surfaces of the third and fourth lip portions. Since each constriction has a constricted part that continues with a curved concave surface, it is easy to deform at the constricted part even if the amount of crushing of the seal increases, and the deformation of the constricted part causes the contact pressure between the lip part and the plate to be Increase can be suppressed. Further, by providing the curved concave surface in the constricted portion, stress concentration can be relaxed in a state where the seal member is crushed.

  As a result, even if the clearance between the inner link plate and the outer link plate is reduced to increase the tensile strength of the chain, the contact pressure between the lip portion and the plate is reduced while preventing the seal member from being crushed too much. Can be ensured properly, and even if the seal chain is slanted and the amount of crushing of the seal becomes uneven, the non-uniformity of the contact pressure can be suppressed. It is possible to alleviate the stress concentration at the connecting portion of the seal and improve the durability of the seal chain.

  According to the second aspect of the present invention, each of the first and second lip portions has a width in the radial base end portion larger than the width (B) of the third and fourth lip portions. And stress concentration can be relieved, ensuring the tension force by the 1st and 2nd lip part, without lengthening the length of a 2nd lip part. That is, when the radius of curvature of the curved concave surface is increased to alleviate stress concentration, there are restrictions on the length of the first and second lip portions, and the radial base end portion and the radial intermediate portion Although it is difficult to increase the difference in width, the width of the proximal end portion in the radial direction is larger than the widths of the third and fourth lip portions. Therefore, stress concentration can be alleviated while securing the tension force by the first and second lip portions without increasing the length of the first and second lip portions.

  According to the third aspect of the present invention, since the first and second lip portions are formed in line symmetry, deformation due to the crushing of the seal member is performed in a well-balanced manner, and the contact pressure between the lip portion and the plate is reduced. It becomes easier to stabilize.

  According to the fourth aspect of the present invention, since the width of the largest width portion (maximum width dimension portion) of the first and second lip portions is within an appropriate range, the seal member is crushed. The tension force of the first and second lip portions can be made appropriate, and the contact pressure between the lip portion and the plate can be made in an appropriate range. That is, if the width of the maximum dimension portion is less than 1.5 times the width of the third and fourth lip portions, the tension force of the first and second lip portions cannot be sufficiently secured, and the lip portion The contact pressure between the plate and the plate tends to be insufficient. On the other hand, when the width of the maximum dimension portion is larger than 1.7 times the width of the third and fourth lip portions, the tension force of the first and second lip portions is too large, The contact pressure with the plate tends to be excessive.

  Therefore, by setting the width of the maximum dimension portion of the first and second lip portions within an appropriate range, it is easier to suppress the leakage of lubricating oil due to insufficient contact pressure, and the chain due to excessive contact pressure. It becomes easier to prevent the deterioration of the bending property and the early wear of the seal member.

  According to the fifth aspect of the present invention, since the curved concave surfaces of the constricted portions of the first and second lip portions have a radius of curvature of 0.12 times or more of the horizontal dimension of the seal member, Stress concentration can be further relaxed in a state where the member is crushed. However, if the radius of curvature is too large, the dimensional difference between the constricted portion and the maximum width dimension portion of the first and second lip portions becomes small, and deformation at the constricted portion becomes difficult. And it becomes difficult to obtain an effect that an increase in contact pressure between the lip portion and the plate due to an increase in the amount of crushing of the seal can be suppressed by the deformation of the constricted portion. Therefore, the radius of curvature of the curved concave surface is preferably 0.2 times or less, more preferably 0.15 times or less, of the horizontal dimension of the seal member.

1 is a partially cutaway view showing a seal chain according to an embodiment of the present invention. The expanded sectional view of the seal member of the natural state of this embodiment. The partial expanded sectional view in the natural state for demonstrating the dimensional relationship of a sealing member. The figure which shows the contact pressure which acts when the amount of seal crushing is changed with the conventional seal member. The figure which shows the contact pressure which acts when the amount of seal crushing is changed with the sealing member of this embodiment. The figure for demonstrating the test conditions performed in order to confirm the effect of this invention. The figure which similarly shows the offset amount of a sprocket. The figure which similarly shows a test result. The partial expanded sectional view which shows the manufacturing method of the seal chain used as the object of this invention in order of a process. The partial expanded sectional view which shows two examples of the conventional sealing member. The partial schematic sectional drawing which shows the offset state of a seal chain.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 8. As shown in FIG. 1, the seal chain 11 has the same shape as an outer (pin) link 19 in which both ends of two steel eyebrow-shaped outer (pin) link plates 18 are connected by pins 12. An inner (roller) link 20 in which both ends of two inner (roller) link plates 16 are connected by a bush 17 is connected endlessly by inserting a pin 12 into the bush 17. Yes. A roller 21 is rotatably fitted to the bush 17, and the bush 17 is fixed so as to protrude from the outer surface of the inner link plate 16 by a predetermined amount. A seal member (seal ring) 13 according to the present embodiment is interposed between the inner link plate 16 and the outer link plate 18 so as to surround the protruding portion 17a of the bush 17. The clearance i between the outer link plate 18 and the inner link plate 16 {there are clearances in the left and right (upper and lower in FIG. 1) link plates, respectively, so that the entire chain becomes 2i} is small. The seal member 13 is disposed in this clearance in a state of being elastically compressed.

As shown in FIG. 2, the seal member 13 is formed by forming an elastic material such as rubber in a ring shape. Is larger than the clearance i. For example, i / H is 50 to 70%. Similar to the case shown in FIG. 9 described above, such a seal member 13 is substantially X-shaped in cross section in the mounted state sandwiched between the inner link plate 16 and the outer link plate 18. Then, a lubricant such as grease or oil is sealed in the bearing space between the pin 12 and the bush 17. The seal member 13 is compressed by a predetermined amount between the outer link plate 18 and the inner link plate 16 in a mounted state, but the rubber that is a material of the seal member 13 is made of a relatively hard material. ing.

  Such a natural shape of the seal member 13 of this embodiment will be described with reference to FIGS. The seal member 13 includes a central base portion 13e, a first lip portion 13a extending from the central base portion 13e in the inner diameter direction, a second lip portion 13b extending from the central base portion 13e in the outer radial direction, and the central base portion 13e. It has 3rd and 4th lip | rip parts 13c and 13d extended in the left-right direction (up-down direction of FIG. 2, 3).

In the case of the present embodiment, the seal member 13 is formed in line symmetry with respect to a center line OO orthogonal to the radial direction (left and right direction in FIGS. 2 and 3) in the cross-sectional shape thereof. Accordingly, the first and second lip portions 13 a and 13 b are formed symmetrically with respect to the center line OO perpendicular to the radial direction in the cross section of the seal member 13. The first and second lip portions 13a and 13b have a circular shape in cross section in which the outer peripheral surface of the radial intermediate portion or the distal end portion is formed by a round (arc) surface 13g. It has a constricted portion 13f that is narrower than the middle portion in the direction. And the continuous part of the lateral direction both sides of the 1st and 2nd lip parts 13a and 13b and the diameter direction both end faces of the 3rd and 4th lip parts 13c and 13d which are the side of constriction part 13f The curved concave surface 13h is used. In other words, by these curved concave surfaces 13h, the left and right side surfaces of the first and second lip portions 13a and 13b and the radial end surfaces of the third and fourth lip portions 13c and 13d are smoothly continuous. ing. Further, the curved concave surface 13h is continuous smoothly with the curved surface r _1. “Smooth” means that there is no local unevenness and local stress concentration is difficult to occur during deformation.

The radius of curvature _{r 1} of the aforementioned curved surface 13g is preferably to 0.15 times to 0.25 times the lateral dimension H of the sealing member 13, it is particularly preferable to be 0.2 times. The curvature radius _{r 2} of the concave curved surface 13h of the aforementioned, and 0.12 times in the lateral direction of the dimension H of the sealing member 13. Incidentally, the curvature radius r ₂ is preferably not more than 0.2 times the lateral dimension H of the sealing member 13, and more preferably 0.15 times or less.

  Further, the first and second lip portions 13a and 13b have a width A at the radial intermediate portion larger than the width B of the third and fourth lip portions 13c and 13d, respectively. Further, the width C of the narrowest portion 13f of the first and second lip portions 13a and 13b in the radial direction from the base end portion to the intermediate portion is also the width B of the third and fourth lip portions 13c and 13d. Bigger than. Further, the width A of the largest portion (maximum dimension portion) of the first and second lip portions 13a and 13b is 1.5 to the width B of the third and fourth lip portions 13c and 13d. 1.7 times. The width A of the maximum dimension portion is preferably 0.35 to 0.45 times the width dimension H of the seal member 13. Furthermore, the width C of the constricted portion 13f can be 1.2 to 1.4 times the width B of the third and fourth lip portions 13c and 13d.

Further, the protruding amount L of the first and second lip portions 13a and 13b from the both end surfaces in the radial direction of the third and fourth lip portions 13c and 13d is the width B of the lip portions 13c and 13d. It is preferable that the width is 1.8 to 2.2 times, preferably about 2 times, and 0.4 to 0.6 times, preferably about 0.5 times the width dimension H of the seal member 13. These are summarized as follows.
A: B = 1.5 to 1.7: 1
A: H = 0.35-0.45: 1
C: B = 1.2 to 1.4: 1
L: B = 1.8-2.2: 1
L: H = 0.4-0.6: 1

  Further, the seal member 13 is formed in line symmetry with respect to a center line NN perpendicular to the left-right direction (the vertical direction in FIGS. 2 and 3) in its cross-sectional shape. Therefore, the third and fourth lip portions 13c and 13d are formed symmetrically with respect to the center line NN perpendicular to the left-right direction in the cross section of the seal member 13. Accordingly, the third and fourth lip portions 13c, 13d have the same amount of protrusion from the left and right side surfaces of the first and second lip portions 13a, 13b. Further, the third and fourth lip portions 13c, 13d are formed to have substantially the same width in the left-right direction except for a continuous portion with the curved concave surface 13h. Further, the corner of the tip is chamfered or curved. Note that the third and fourth lips 13c and 13d may have a shape such that the width decreases toward the tip, for example, in addition to the substantially same width in the left-right direction as illustrated. In this case, the width B is an average value. Further, the shapes of the third and fourth lip portions 13c and 13d can be made not to coincide with each other. In this case, the width B is equal to the width of the third and fourth lip portions 13c and 13d. Determine the larger one as a standard.

In the case of this embodiment as well, as in the case described with reference to FIG. 9 , the seal member 13 is arranged as follows. First, the outer link plate 18 is moved in a direction approaching the inner link plate 16 in a state where the first lip portion 13a is disposed between the distal end of the bush protrusion 17a and the outer link plate 18. Then, the seal member 13 is twisted by a rotational moment based on the contact with the bushing projecting portion 17a and deformed into a substantially X-shaped cross section, and is sandwiched between the inner link plate 16 and the outer link plate 18. Is done.

  According to this embodiment, since the first and second lip portions 13a and 13b have the radial intermediate width larger than the third and fourth lip width B, the seal member 13 is pushed. In the crushed state, the first and second lip portions 13a and 13b are sufficiently stretched against the plates 16 and 18, and the contact pressure between the lip portion 13a and the plate 18 can be secured. In this case, the contact pressure is determined by setting the relationship between the width A of the maximum width dimension portion of the first and second lip portions 13a and 13b and the B to A: B = 1.5 to 1.7: 1. It is possible to prevent the contact pressure from becoming insufficient or the contact pressure from becoming excessive.

  Further, the radial base end portion is narrower than the radial intermediate portion, and both the left and right side surfaces of the first and second lip portions 13a and 13b and the third and fourth lip portions 13c, Since it has a constricted portion 13f that allows both end surfaces in the radial direction of 13d to be continuous by curved concave surfaces 13h, the constricted portion 13f is easily deformed even if the seal collapse amount increases, and the deformation of the constricted portion 13f reduces the amount of seal collapse. An increase in the contact pressure between the lip portions 13a and 13b and the plates 16 and 18 due to the increase can be suppressed. That is, in the case of the present embodiment, the first and second lip portions 13a and 13b are increased in width to secure the necessary contact pressure, and by providing the constricted portion 13f, the inner link plate 16 and the outer link When the clearance with the link plate 18 is reduced and the seal crushing amount is increased, the contact portion 13f is deformed to suppress an increase in contact pressure.

Further, by providing the curved concave surface 13h in the constricted portion 13f, stress concentration can be relaxed in a state where the seal member 13 is crushed. In this case, if the curved concave surface 13h has a curvature radius larger than 0.12 times the dimension H in the left-right direction of the seal member 13, the stress concentration can be further relaxed in a state where the seal member is crushed. However, too large a radius of curvature r _2, constricted portion 13f and the first and second lip portions 13a, dimensional difference between the maximum width portion of 13b becomes small, upcoming since hardly deformed constricted portion 13f , the radius of curvature _{r 2} of the concave curved surface 13h is 0.2 times the lateral dimension H of the sealing member 13 or less, more preferably 0.15 times or less.

In the case of this embodiment, although a larger radius of curvature r ₂ of the concave curved surface 13h for relaxation of stress concentration, there are constraints on the length of the first and second lip portions, the It is difficult to increase the difference in width between the radial base end portions and the radial intermediate portions of the first and second lip portions 13a and 13b. However, in the case of this embodiment, since the width C of the radial base end portion is larger than the widths of the third and fourth lip portions 13c and 13d, the tension force is reduced even if the difference cannot be increased. Is suppressed. Therefore, stress concentration can be alleviated while securing the tension force by the first and second lip portions 13a and 13b without increasing the length of the first and second lip portions.

The relationship between A and the width H in the left-right direction of the seal member 13 is A: H = 0.35 to 0.45: 1, and the protrusion amount L of the first and second lip portions 13a and 13b By setting the relationship with H to L: H = 0.4 to 0.6: 1, the relationship between the width in the left-right direction and the width in the radial direction in the natural state of the seal member 13 can be appropriately set and mounted. In this state, each lip portion can be appropriately brought into contact with the plate 16 or 18 or the bush protrusion 17a. Further, by having such a relationship, the curved concave surface 13h can be easily formed with an appropriate radius of curvature, stress concentration can be easily relaxed, and the constricted portion 13f can be easily deformed appropriately. For example, when the protrusion amount L is too small, in order to the concave curved surface 13h with an appropriate radius of curvature, the width of the constricted portion 13f becomes too large, it is difficult to deform the constriction 13 f.

  For the third and fourth lips 13c and 13d, a width satisfying A: B = 1.5 to 1.7: 1 and A: H = 0.35 to 0.45: 1, that is, By setting B: H≈0.2 to 0.3: 1, it is possible to secure the necessary tension force and prevent the tension force from becoming excessive. As a result, the contact pressure based on the tension force by the first and second lip portions 13a and 13b as described above can be further stabilized. For example, when the widths of the third and fourth lip portions 13c and 13d are too small, the tension force is small and it is difficult to maintain a predetermined X-shaped cross section in the state where the seal member 13 is assembled in the first place. On the other hand, when the widths of the third and fourth lip portions 13c and 13d are too large, the tension force is large, and it becomes difficult to smoothly deform the above-described constricted portion 13f due to the reduction of the clearance.

  In the case of this embodiment, since the first and second lip portions 13a and 13b are formed in line symmetry, deformation caused by crushing the seal member 13 is performed in a well-balanced manner, and the lip portions 13a and 13b and the plate It becomes easy to stabilize the contact pressure with 16 and 18 more. However, the present invention is not limited to such a structure, and the first and second lip portions 13a and 13b may be asymmetric. In this case, it is preferable that the first and second lip portions 13a and 13b fall within the above-described numerical relation range. In this case, since the first and second lip portions 13a and 13b are asymmetrical, it goes without saying that the numerical values themselves applied to them are different. Further, the third and fourth lip portions 13c and 13d are not limited to line symmetry, and can be handled in the same manner as the first and second lip portions 13a and 13b.

  In the case of the present embodiment, even if the clearance i between the inner link plate 16 and the outer link plate 18 is reduced to increase the tensile strength of the chain as a result of having the configuration and operation as described above, the seal member 13 The contact pressure between the lip portions 13a and 13b and the plates 16 and 18 can be appropriately secured, and the seal chain 11 is slanted to make the amount of seal crush uneven. In addition, the contact pressure non-uniformity can be suppressed, and furthermore, the stress concentration at the connecting portions of the lip portions 13a, 13b, 13c, and 13d can be alleviated with the seal member 13 being crushed, and the durability of the seal chain is improved. Be made.

  Next, as a result of examining the difference in the contact pressure change with respect to the change in the seal crushing amount between the seal member of the present embodiment and the seal member having the conventional structure having the shape as shown in FIG. Will be described with reference to FIGS. In this embodiment and the conventional example, in the natural state, the horizontal dimension (corresponding to H) and the radial dimension (corresponding to 2L + B) of the seal member are the same. As for other dimensional relationships, in the present embodiment, the above-described relationship is satisfied, and in the conventional example, the relationship described in FIG. 10B is satisfied.

  Then, when the clearance i between the outer link plate and the inner link plate on which such a seal member is arranged is changed, the contact pressure acting on each contact portion is obtained by calculation. The results are shown in FIGS. 4 is a conventional example, and FIG. 5 is a cross-sectional view of the present embodiment in a state in which the seal member is disposed between the outer link plate, the inner link plate, and the bushing protrusion. Each (a) shows a case where i / H is 0.5, (b) shows i / H is 0.6, and (c) shows i / H is 0.7. It is assumed that the clearance i among these is a regular clearance in the use state of the seal chain. In addition, the black-painted portion in each figure shows the magnitude of the contact pressure and the location where it acts. The higher the height, the greater the contact pressure. Moreover, the upper side of each figure corresponds to the contact portion of the outer link plate, the lower side corresponds to the contact portion of the inner link plate, and the left side corresponds to the contact portion of the protruding portion of the bush. Therefore, the upper left of the cross section of the seal member is the first lip, the lower right is the second lip, the upper right is the third lip, and the lower left is the fourth lip.

  In the case of the conventional example of FIG. 4, the contact pressure of the contact portion between the first lip portion and the outer link plate at the upper left of the drawing is greatly changed due to a decrease in clearance i, that is, an increase in the amount of seal crushing. Recognize. Further, in the normal state (c), it is found that there are few places where the contact pressure is high to some extent in this portion, and the average value of the contact pressure is low. Since the contact portion between the first lip portion and the outer link plate is close to the bearing space in which the lubricant is most enclosed, it is an important portion for preventing leakage of the lubricant. In general, the contact portion between the seal member and the outer link plate slides in use. For this reason, when the contact pressure is too high, the flexibility of the chain is deteriorated and the seal member is likely to be worn early. And it becomes easy to leak a lubricant, and the lifetime of a chain will become short.

  Therefore, in the case of the conventional example of FIG. 4, when the clearance is in a normal state, the contact pressure between the first lip portion and the outer link plate is small, so that the lubricant is likely to leak. On the other hand, when the clearance is small, the contact pressure at this portion is too high, so that the flexibility of the chain may be deteriorated or the seal member may be worn early. In particular, as described above, when an offset state of the chain occurs, the clearance becomes non-uniform and the seal crushing amount of the seal member also changes. For this reason, the state of (a)-(c) of a figure is repeated by the drive of a chain, and in the case of the prior art example of FIG. 4, the contact pressure of a 1st lip | rip part and an outer link plate changes a lot. Will be repeated.

  On the other hand, in the case of the present embodiment of FIG. 5, the contact pressure of the contact portion between the first lip portion and the outer link plate at the upper left of the drawing is due to a decrease in clearance i, that is, an increase in the amount of seal crushing. It can be seen that the amount of change is small. In the normal state (c), it can be seen that the contact pressure is high to some extent in this portion, and the average value of the contact pressure is high. Therefore, in the case of the present embodiment of FIG. 5, even when the clearance is in a normal state, the contact pressure between the first lip portion and the outer link plate can be ensured, and leakage of the lubricant can be suppressed. On the other hand, even in a state where the clearance is reduced, it is possible to suppress an increase in the contact pressure of this portion, and it is possible to suppress deterioration of the flexibility of the chain and early wear of the seal member. Therefore, even if the chain is in an offset state, the change in contact pressure between the first lip portion and the outer link plate is small, and stable chain driving can be maintained over a long period of time.

Next, the durability test of the seal chain 11 incorporating the seal member 13 of the present embodiment will be described. As a chain, JIS 50 was used. The dimensional relationship of the shape of the seal member 13 is as follows.
A: B = 1.5 to 1.7: 1
A: H = 0.35-0.45: 1
C: B = 1.2 to 1.4: 1
L: B = 1.8-2.2: 1
L: H = 0.4-0.6: 1
r ₁ : H = 0.15 to 0.25: 1
r _2: H = 0.12~0.2: 1

Then, as shown in FIG. 6, the seal chain 11 incorporating the seal member 13 having such a shape is passed over a large sprocket 30 having a large number of teeth and a small sprocket 31 having a small number of teeth, and a predetermined tensile tension T Was rotated at a predetermined number of revolutions. The large sprocket 30 and the small sprocket 31 were offset by a predetermined amount δ as shown in FIG. The test conditions are as follows.
Number of teeth of large sprocket 30: Number of teeth of small sprocket 31 = 43: 15
Chain tension T = 1.96kN
Number of rotations of small sprocket 31 = 3500 rpm
Offset amount δ = 8mm

  The sample was rotated under such test conditions, and the elongation of the seal chain 11 (product of the present invention) after a predetermined time elapsed was measured. In addition, the test was performed indoors at normal temperature and humidity with no air supply every 20 hours. In addition, a durability test was performed on a seal chain (conventional product) incorporating the conventional seal member shown in FIG. 10B under the same test conditions. The test results are shown in FIG. FIG. 8 shows the elongation of the seal chain with respect to the driving time. The time when the elongation of the conventional seal chain reaches 0.5% is defined as 100%. As is apparent from FIG. 8, in the case of the product of the present invention, the durability could be more than doubled compared to the conventional product.

DESCRIPTION OF SYMBOLS 11 Seal chain 12 Pin 13 Seal member 13a 1st lip part 13b 2nd lip part 13c 3rd lip part 13d 4th lip part 13e Central base part 13f Constriction part 13g Earl surface 13h Curved concave surface 16 Inner link plate 17 Bush 17a Bush protrusion 18 Outer link plate 19 Outer link 20 Inner link 21 Roller i Clearance between both link plates r ₁ Curvature radius of first and second lip portion radius surface r ₂ Curvature radius of curved concave surface A First and second Lip portion maximum dimension portion B width of third and fourth lip portions C width of constricted portion H width dimension of seal member in left-right direction L protrusion amount of first and second lip portions

Claims (5)

A bush-shaped seal member is arranged so as to partially protrude the bush from the inner link plate, and to be sandwiched between the inner link plate and the outer link plate so as to surround the protruding portion.
The seal member has a cross-section in a natural state having a cross shape, a central base, a first lip extending from the central base in the inner diameter direction, and a second lip extending from the central base in the outer diameter direction, A third lip portion and a fourth lip portion extending in the left-right direction from the central base portion;
In a state where the first lip portion is disposed between the projecting end of the bush and the outer link plate, the outer link plate is moved in a direction approaching the inner link plate, and the seal member is In a seal chain that is twisted by a rotational moment based on contact with the bushing protrusion and deformed into a substantially X-shaped cross section and is sandwiched between the inner link plate and the outer link plate,
In a natural state, the first lip portion has a round cross section formed by a round surface or a curved surface close thereto or a shape close thereto,
Each of the first and second lip portions has a width in the radial intermediate portion that is larger than the widths of the third and fourth lip portions, and the width in the radial base end portion is larger than that in the radial intermediate portion. Is narrow, and has constricted portions that allow both the left and right side surfaces of the first and second lip portions and the radial end surfaces of the third and fourth lip portions to be continuous with curved concave surfaces, respectively.
A seal chain characterized by that. In the natural state, each of the first and second lip portions has a radial base end portion having a width greater than that of the third and fourth lip portions.
The seal chain according to claim 1. In the natural state, the first and second lip portions are formed in line symmetry with respect to a center line orthogonal to the radial direction in the cross section of the seal member.
The seal chain according to claim 1 or 2, wherein In the natural state, the width of the largest portion of the first and second lip portions is 1.5 to 1.7 times the width of the third and fourth lip portions.
The seal chain according to any one of claims 1 to 3, characterized in that: In a natural state, the curved concave surfaces of the constricted portions of the first and second lip portions have a radius of curvature that is equal to or greater than 0.12 times the horizontal dimension of the seal member.
The seal chain according to any one of claims 1 to 4, wherein the seal chain is provided.

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