JP5788224B2 - Seal ring for chain and roller chain using it - Google Patents

Description

  The present invention relates to a seal ring for a chain that can improve sealing performance and durability without excessively increasing the bending resistance of the chain, and a roller chain using the seal ring.

  A non-lubricated roller chain that does not require lubrication incorporates a seal ring to prevent leakage of oil sealed between the pin and the bush attached to the pin.

  A conventional seal ring is a so-called X-ring, and has an X-shaped cross-sectional shape that is symmetrical in the vertical and horizontal directions. In contrast, the inner and outer seal lips must be formed asymmetrically so that the axial compressive strength of the inner seal lip is significantly greater than that of the outer seal lip. Is known (Patent Document 1). Such a seal ring can reduce the frictional resistance of the large-diameter seal formed by the seal lip on the outer peripheral side, so that the bending resistance of the chain can be kept small and the durability of the seal ring can be improved. .

Japanese Patent No. 4317358

  According to such a conventional technique, the ease of incorporation into the chain, the low bending resistance, the durability, etc. of the chain can be improved as compared with the X ring used previously. However, in recent years, the usage environment of chains has become more severe, and there is an increasing demand for further performance improvement of chains including seal rings.

  Accordingly, an object of the present invention is to provide a seal ring for a chain that can further improve the sealing performance and durability while maintaining the conventional good performance, and a roller chain using the same. There is to do.

  In order to achieve this object, the structure of the invention of claim 1 includes an inner peripheral groove provided on the inner peripheral side, a pair of inner peripheral lips provided across the inner peripheral groove, an outer peripheral groove provided on the outer peripheral side, and an outer peripheral groove. A pair of outer peripheral lips provided between the inner peripheral lips, each inner peripheral lip forming an axial tip by an annular rib protruding in the axial direction, and a radial direction between the inner peripheral tip and the axial tip The distance L2 is made larger than the depth L1 of the inner circumferential groove, and the inner circumferential side tip and the annular rib are smoothly connected by a concave surface for guide when the seal ring is fitted into the bush. Reinforcing ribs projecting in the radial direction are formed at the bottom of the ring, and the minimum inner diameter D1 by the tip on the inner peripheral side, the outer diameters Dp and Db of the chain pin and bush, The distance Lb to the outer diameter of the flat surface is Dp + 2Lb ≤D1 As its gist to set to Db <D1 + 2L2.

  The configuration of the invention of claim 2 includes an inner peripheral groove provided on the inner peripheral side, a pair of inner peripheral lips provided across the inner peripheral groove, an outer peripheral groove provided on the outer peripheral side, and a pair of outer peripheries provided across the outer peripheral groove. Each inner circumferential lip has an axial tip formed by an annular rib protruding in the axial direction, and the radial distance between the inner circumferential tip and the axial tip is an inner circumferential groove. A reinforcing rib protruding in the radial direction is formed at the bottom of the outer circumferential groove, and an intermediate groove opening in the axial direction is formed between the inner circumferential lip and the distal end in the axial direction of the outer circumferential lip. The gist of the intermediate groove is to form a stepped portion that widens the half on the opening side.

  The structure of the invention of claim 3 includes a pair of outer link plates that are flexibly connected via pins and bushes, an inner link plate, and a roller that is rotatably mounted between the inner link plates via the bushes, 3. The seal ring for a chain according to claim 1 or 2, wherein the seal ring is provided between each outer link plate and the inner link plate via a tip portion of a bush projecting to the outside of the inner link plate. The gist is that at least one inner peripheral lip forms a seal on the outer peripheral surface of the bush, and the outer peripheral lip and the annular rib form a seal on the outer link plate and the surface of the inner link plate.

  When the seal ring is properly assembled in the roller chain, at least one inner peripheral lip forms a seal on the outer peripheral surface of the bush, and each annular rib, outer peripheral lip is formed. Form a seal on the surface of the corresponding outer link plate or inner link plate, respectively. At this time, since the annular rib on the inner peripheral lip compressed in the axial direction has a small contact area with the outer link plate or the surface of the inner link plate, the compressive strength in the axial direction is small and the sealing pressure is increased. Sealing performance can be realized. Since the inner peripheral lip does not need to be compressed substantially in the axial direction, the compressive strength in the axial direction may be large, and the outer peripheral lip elastically deforms in a direction approaching each other toward the outer peripheral groove, The compressive strength in the direction is sufficiently small. Therefore, the frictional resistance of the seal by the annular rib and the outer peripheral lip is sufficiently small, and the bending resistance of the chain resulting from the frictional resistance can be kept small, and the durability of the seal ring can be improved.

  Each inner peripheral lip has a greater radial rigidity between the inner peripheral side tip and the axial front end than the depth of the inner peripheral groove, thereby increasing rigidity and increasing the axial compressive strength. The distance between the axial tips including the ribs can be minimized. The inner peripheral groove between the inner peripheral lips forms an oil sump with the outer peripheral surface of the bush. Further, the reinforcing rib provided at the bottom of the outer circumferential groove increases the strength against the shearing force caused by the relative rotation of the inner link plate and the outer link plate generated when the chain is bent, and further improves the durability of the seal ring. However, it is preferable that the reinforcing rib be lower than the depth of the outer peripheral groove so as not to prevent the outer peripheral lips on both sides of the outer peripheral groove from being elastically deformed in a direction approaching each other.

  The seal ring is integrally formed in a ring shape having a uniform cross section as a whole. The material of the seal ring is preferably a synthetic rubber material such as nitrile rubber, hydrogenated nitrile rubber, or fluorine rubber, and can be appropriately selected depending on the use conditions including temperature conditions.

  The concave surface that smoothly connects the tip of the inner peripheral side of each inner peripheral lip and the annular rib properly guides the seal ring to the center of the bush when fitting the seal ring into the bush. Reduces friction and prevents harmful twisting.

  If the inner peripheral lip and the outer peripheral lip are arranged so that the respective centerlines are orthogonal to each other, the radial cross-sectional dimension can be minimized and the adaptability to a small chain can be increased.

  When the step portion is provided in the intermediate groove, the outer peripheral lip is easily elastically deformed toward the outer peripheral groove, and the cross-sectional area of the intermediate groove is increased, so that the capacity as a grease reservoir can be increased.

  According to the configuration of the invention of claim 3, at least one inner peripheral lip of the seal ring forms a seal on the outer peripheral surface of the bush, and each annular rib and outer peripheral lip are on the outer link plate and the inner link plate. By forming a seal on the base, leakage of oil enclosed between the pin and the bush can be effectively prevented without increasing the bending resistance of the chain. In addition, the distance between the axial ends of the inner peripheral lip can be reduced, and the overall strength of the chain can be improved.

Expanded cross-sectional view of the main parts of the roller chain Enlarged sectional view of the main part of the seal ring Illustration of assembly state of seal ring Illustration of seal ring usage FIG. 2 equivalent view showing another embodiment

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  The roller chain is formed by flexibly connecting a pair of outer link plates 23 and 23 and inner link plates 24 and 24 via pins 21 and bushes 22 (FIG. 1). However, FIG. 1 is a schematic cross-sectional view of a connecting portion by a specific pin 21, and the roller chain has a large number of outer link plates 23, 23... Link plates 24, 24... Are continuously linked in the left-right direction in FIG.

  A bush 22 is attached to the pin 21 so as to be relatively rotatable. Both ends of the pin 21 are inserted and crimped into the pin holes 23a of the outer link plate 23, respectively, and both ends of the bush 22 are press-fitted into the pin holes 24a of the inner link plate 24, respectively. Both ends of the pin 21 and both ends of the bush 22 protrude to the outside of the outer link plate 23 and the inner link plate 24, respectively, and the roller 25 is relatively rotatable between the inner link plates 24 and 24 on the bush 22. It is installed.

  Between the outer link plates 23, 23 and the inner link plates 24, 24 at both ends of the pin 21, the seal ring 10 is interposed via the tip of the bush 22 that protrudes outside the inner link plate 24. Yes. Each seal ring 10 is compressed in the axial direction by the outer link plate 23 and the inner link plate 24 and elastically deformed to form a seal on each surface of the outer link plate 23 and the inner link plate 24, and the inner link plate 24. A seal is also formed on the outer peripheral surface of the outer bushing 22 to prevent leakage of oil sealed between the pin 21 and the bushing 22.

  The free shape of the seal ring 10 is shown in FIG.

  The seal ring 10 includes a smooth concave inner peripheral groove 11 provided on the inner peripheral side, a pair of inner peripheral lips 12 and 12 provided symmetrically across the inner peripheral groove 11, and a smooth concave shape provided on the outer peripheral side. Outer peripheral groove 13 and a pair of outer peripheral lips 14, 14 provided symmetrically with respect to the outer peripheral groove 13. In this case, the left-right symmetry means that it is symmetric with respect to an imaginary plane PL that is orthogonal to the axis C and passes through the middle of the inner peripheral ends 12c, 12c of the inner peripheral lips 12, 12. The inner peripheral lips 12 and 12 and the outer peripheral lips 14 and 14 are arranged so that the respective center lines CL2 and CL4 are perpendicular to each other at one point on the virtual plane PL. However, the inner peripheral lip 12 and the outer peripheral lip 14 may not have their center lines CL2 and CL4 aligned with each other and do not need to intersect at one point on the virtual plane PL.

  Each inner peripheral lip 12 has an inner peripheral side distal end 12c that is smooth inward, and an annular rib 12a that protrudes in the axis C direction forms an end 12b in the axis C direction. The tip 12b of the annular rib 12a is formed in a mountain shape with a circular arc cross section, and the tip 12b is suitable in terms of sealing properties and formability if the radius of curvature is 0.1 to 0.2 mm. Each inner peripheral lip 12 has a radial distance L2 between the inner peripheral side tip 12c and the tip 12b in the axis C direction such that L2> L1 with respect to the depth L1 of the inner peripheral groove 11, and the tip 12c and the annular rib 12a. Are smoothly connected by a concave surface 12d.

  Each outer peripheral lip 14 has a tip 14a in the direction of the axis C, and the tip 14a formed in a mountain shape having an arcuate cross section has a sealing property and a formability surface if the curvature radius is 0.1 to 0.2 mm. It is suitable. Further, the outer peripheral side of the tip 14a of each outer peripheral lip 14 is formed as a slope 14b having an inclination angle θb <45 ° with respect to the radial direction, and each slope 14b has a smooth outward convex shape and the outer peripheral groove 13. It is connected to the. An annular reinforcing rib 16 protruding in the radial direction is formed on the virtual plane PL at the bottom of the outer circumferential groove 13. The reinforcing rib 16 is formed in a symmetrical symmetrical mountain shape, and is formed such that the height L6 <L3 with respect to the depth L3 of the outer circumferential groove 13.

  The distance H1 between the tips 12b, 12b of the inner peripheral lips 12, 12 in the axis C direction is H1≤H3 with respect to the distance H3 between the tips 14a, 14a of the outer peripheral lips 14, 14 in the axis C direction. However, in FIG. 2, it is shown as H1 = H3.

  A concave intermediate groove 15 opening in the axis C direction is formed between the tip 12b of each inner peripheral lip 12 in the axis C direction and the tip 14a of each outer peripheral lip 14 in the axis C direction. The intermediate grooves 15 and 15 are formed as a pair symmetrical to the virtual plane PL. On the inner and outer peripheral sides of each intermediate groove 15, step portions 15 a and 15 b that widen the half of the opening side of the intermediate groove 15 are formed symmetrically. The inner surfaces of the intermediate groove 15 including the step portions 15a and 15b are all smoothly connected.

  The seal ring 10 includes a minimum inner diameter D1 due to the inner peripheral ends 12c and 12c of the inner peripheral lips 12 and 12, an outer diameter Dp of the pin 21, an outer diameter Db of the bush 22, and an end of the bush 22 from the inner peripheral surface of the bush 22. As the radial distance Lb to the outer diameter of the ring-shaped flat surface 22a, the relational dimension is set so that Dp + 2Lb ≦ D1 <Db <D1 + 2L2 is satisfied (FIGS. 1 and 3). However, both ends of the bush 22 are slightly chamfered on the inner peripheral surface side, and the outer peripheral surface side is smoothly rounded to an appropriate curvature radius. In FIG. 3, the distance Lb is shown by Dp + 2Lb <D1.

  The seal ring 10 can be fitted to the tip of the bush 22 so as to extend the entire length (in the direction of arrow A in FIG. 3). At this time, the concave surface 12d on the bush 22 side of the seal ring 10 appropriately To automatically center on the center of the bush 22. It is assumed that the inner peripheral groove 11 remains on the inner peripheral side of the seal ring 10 fitted into the bush 22 and is shallower than the depth L1 before fitting into the bush 22.

  When each seal ring 10 is properly assembled in the roller chain, it is sandwiched between the outer link plate 23 and the inner link plate 24 and is compressed in the direction of the axis C to be elastically deformed (FIGS. 1 and 4). At this time, the inner peripheral ends 12c and 12c of the inner peripheral lips 12 and 12 are elastically contacted with the outer peripheral surface of the bush 22 to form a double seal. Further, the tip 12b in the axis C direction of one inner peripheral lip 12 by the annular rib 12a and the tip 14a in the axis C direction of the outer peripheral lip 14 are elastically abutted on the surface of the outer link plate 23 to have a small diameter and large diameter. A double seal with a diameter is formed, and the other ends 12b and 14a abut against the surface of the inner link plate 24 to form a double seal. However, in FIG. 4, both the annular ribs 12a and 12a are compressed in the direction of the axis C and disappear.

  Further, the seal ring 10 has a shaft C as long as the distance B between the intermediate grooves 15 and 15 is smaller than the interval S between the outer link plate 23 and the inner link plate 24 and the step portions 15a and 15b in each intermediate groove 15 are not lost. The intermediate grooves 15, 15 form an oil reservoir between the double seals on the surface of the outer link plate 23 or the inner link plate 24, respectively. Further, the inner peripheral groove 11 between the inner peripheral lips 12, 12 also forms an oil reservoir between the double seals on the outer peripheral surface of the bush 22.

  The inner peripheral lips 12 and 12 are formed with sufficiently large rigidity as compared with the outer peripheral lips 14 and 14 (FIG. 2). As shown in FIG. 4, the outer peripheral lips 14 and 14 are easily inclined toward the outer peripheral groove 13 together with the step 15 b formed on the outer peripheral side of the intermediate groove 15 so as to approach each other. It is elastically deformed. When each outer peripheral lip 14 is inclined toward the outer peripheral groove 13, the inclination angle θ of the inclined surface 14b on the outer peripheral side is increased, preventing dust from entering from the outside and easily dropping the attached dust to the outside.

  By providing the annular ribs 12a and 12a that are easy to compress in the direction of the axis C, the seal ring 10 can improve the sealing performance and durability while maintaining the assemblability and low bending resistance of the conventional product. Further, the distance S between the outer link plate 23 and the inner link plate 24 for mounting the seal ring 10 can be made 10% or less smaller than that of the conventional product, and the strength of the roller chain itself can be increased.

Other embodiments

  The step portions 15a and 15b in each intermediate groove 15 may be omitted (FIG. 5). In FIG. 5, the outer peripheral side of the intermediate groove 15 is substantially parallel to the center line CL4 of the outer peripheral lip 14 and has a gentle slope longer than the inner peripheral side, so that the outer peripheral lip 14 is easily inclined toward the outer peripheral groove 13. It has become.

  Each annular rib 12a is easily compressed in the direction of the axis C, has a small contact area with the outer link plate 23 or the inner link plate 24, and can realize a good sealing property. It is good also as a cross-sectional shape. Further, the seal ring 10 abuts only the inner peripheral side tip 12c of one inner peripheral lip 12 on the inner link plate 24 side on the outer peripheral surface of the bushing 22, and provides a single seal on the outer peripheral surface of the bushing 22. It may be formed. That is, at least one of the inner peripheral lips 12, 12 may form a seal on the outer peripheral surface of the bush 22.

  The material of the seal ring 10 is butadiene rubber, styrene-butadiene rubber, isoprene rubber, ethylene-propylene rubber, butyl rubber, chloroprene rubber, acrylic rubber, urethane rubber, silicone rubber, polysulfide rubber, polyether rubber, chlorosulfonated. Synthetic rubber materials such as polyethylene rubber can also be used.

  The present invention can be particularly preferably applied to a roller chain having a severe use condition such as a motorcycle traveling chain.

C ... shafts CL2, CL4 ... center line L1 ... depth L2 ... distance 10 ... seal ring 11 ... inner peripheral groove 12 ... inner peripheral lip 12a ... annular rib 12b, 12c ... tip 12d ... concave surface 13 ... outer peripheral groove 14 ... outer peripheral lip DESCRIPTION OF SYMBOLS 15 ... Intermediate groove 15a, 15b ... Step part 16 ... Reinforcement rib 21 ... Pin 22 ... Bush 23 ... Outer link plate 24 ... Inner link plate 25 ... Roller

Patent Applicant Enuma Chain Manufacturing Co., Ltd.

Claims (3)

An inner peripheral groove provided on the inner peripheral side, a pair of inner peripheral lips provided across the inner peripheral groove, an outer peripheral groove provided on the outer peripheral side, and a pair of outer peripheral lips provided across the outer peripheral groove, wherein each inner peripheral lip, the annular rib projecting axially to form the tip of the axial depth of the inner peripheral groove of the radial distance L2 of the tip of the inner circumference side and the distal end of said axial L1 The groove is formed larger, and the concave surface for guiding when the seal ring is fitted into the bushing smoothly connects between the tip on the inner peripheral side and the annular rib, and the bottom of the outer peripheral groove has a radial direction. A protruding reinforcing rib is formed, and the minimum inner diameter D1 by the tip on the inner peripheral side, the outer diameters Dp and Db of the pins of the chain and the bush, the outer diameter of the ring-shaped flat surface from the inner peripheral surface of the bush to the tip of the bush As a distance Lb, Dp + 2Lb ≦ D1 <Db <D1 + 2L2 Seal ring for chains, characterized by setting . An inner peripheral groove provided on the inner peripheral side, a pair of inner peripheral lips provided across the inner peripheral groove, an outer peripheral groove provided on the outer peripheral side, and a pair of outer peripheral lips provided across the outer peripheral groove, Each inner peripheral lip forms an axial tip by an annular rib protruding in the axial direction, and the radial distance between the inner peripheral tip and the axial tip is larger than the depth of the inner groove. Forming a reinforcing rib projecting in the radial direction at the bottom of the outer circumferential groove, and forming an axial groove opening in the axial direction between the inner circumferential lip and the distal end in the axial direction of the outer circumferential lip; the intermediate groove, the sealing ring for the chain which is characterized that you form a stepped portion for widening the half portion on the opening side. A pair of outer link plates and inner link plates that are flexibly connected via pins and bushes, rollers that are rotatably mounted between the inner link plates via the bushes, and outside the inner link plates The chain seal ring according to claim 1 or 2 , wherein the seal ring is interposed between the outer link plate and the inner link plate via a projecting tip of the bush. At least one of the inner peripheral lips forms a seal on the outer peripheral surface of the bush, and the outer peripheral lip and the annular rib form a seal on the outer link plate and the inner link plate. Roller chain.

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