JP3556724B2 - Crawler sealing device - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a crawler belt sealing device for a tracked vehicle such as a bulldozer and an excavator.
[0002]
[Prior art]
Generally, a tracked track of a tracked vehicle is formed by connecting a number of outer links and inner links, and adjacent outer links and inner links are connected by link pins and bushes. When earth and sand or the like that enters from the gap between these links enters between the link pin and the bush, the outer surface of the link pin and the inner surface of the bush are worn, and the life of the crawler belt is significantly shortened. Therefore, in order to prevent such intrusion of soil and the like, a packing chamber is formed on the side of the outer link, and various seal packing rings are mounted as sealing devices in the packing chamber.
[0003]
Japanese Utility Model Publication No. Hei 5-41982 discloses a seal packing ring (seal member) in which a reinforcing rib 13 that opposes the pressing force of the bush is formed on an inner end surface of a gap side. FIG. 8 shows a partial cross-sectional view of the seal member in the above publication.
[0004]
Further, in the specification of Japanese Utility Model Application No. 63-128191, a pocket groove 14 is formed on the back surface 7 side and a heel portion 15 is formed on the inside in order to prevent running out of lubricating oil. A crawler belt sealing device using a seal packing ring (packing ring) set lower than 7 is disclosed (see FIG. 9). When this packing ring is mounted in the packing chamber 2a and pushed by the bush 3, the heel portion 15 first comes into contact with the bottom surface of the packing chamber 2a, and the tightening pressure suddenly increases. When the packing ring is further pushed by the bush 3, the packing ring is crushed and set until the pocket groove 14 disappears.
[0005]
[Problems to be solved by the invention]
However, the seal packing ring (seal member) in the crawler belt link sealing device disclosed in Japanese Utility Model Publication No. 5-41982 has a high initial tightening pressure because the reinforcing ribs 13 are provided inside the seal packing ring. In addition, since the load from the bush is applied uniformly to the entire surface of the seal (the front surface of the seal member), the lubricating oil between the bush and the seal surface is likely to run out, and the seal packing ring (seal member) Wear and seizure are likely to occur.
[0006]
Further, in the seal packing ring (packing ring) in the crawler belt sealing device disclosed in Japanese Utility Model Application No. 63-128191, running out of lubricating oil between the bush and the sealing surface is prevented. When the packing ring is worn during use, even if the wear is slight, the rate of decrease in the tightening pressure is high, and the sealing performance of the sealing device may be impaired ((c in FIG. 10). ), The change rate ΔP of the tightening pressure, where (c) in FIG. 10 is this known seal packing ring).
[0007]
Further, the seal packing ring in these conventionally known crawler belt sealing devices has a problem that the front surface becomes a mirror surface due to sliding, and a "squeal" phenomenon occurs. It is also desired to improve the retention of the lubricant in front of the seal packing ring and further improve the sealing performance of the sealing device.
[0008]
SUMMARY OF THE INVENTION An object of the present invention is to provide a seal packing ring that prevents wear of lubricating oil on the front face and reduces wear, and prevents a sudden decrease in tightening pressure against thickness displacement due to wear even if worn due to long-term use. The present invention provides a crawler belt sealing device having a long life using the same. It is a further object of the present invention to provide a crawler belt sealing device using a seal packing ring that prevents the occurrence of a "squeal" phenomenon and improves the retention of lubricant.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is to fix an outer link having an annular packing chamber formed inside to both ends of a link pin, and to insert a bush whose end can be inserted into the packing chamber on the link pin. In a crawler belt sealing device comprising an inner link fixed to the bush and a seal packing ring mounted in a packing chamber of the outer link, the seal packing ring has a front face with respect to a horizontal surface facing in a radial direction. An apex having a tapered surface inclined at an angle of 20 ° to 20 ° is formed, and a top having a tapered surface inclined at an angle of 20 ° or less with respect to a horizontal plane toward the inner diameter direction is formed on the back side thereof, and the taper on the back side is formed. A crawler belt sealing device characterized in that the height of the top having a surface is set to be lower than the back surface of the seal packing ring.
[0010]
According to the present invention, an outer link having an annular packing chamber formed inside is fixed to both ends of a link pin, and a bush whose end can be fitted into the packing chamber is inserted on the link pin, and the inner link is formed on the bush. In a crawler belt sealing device having a seal packing ring mounted in a packing chamber of an outer link, the seal packing ring has a taper having a front surface having an inclination of 1 ° to 25 ° with respect to a horizontal plane toward an inner diameter direction. A top having a surface is formed, and a top having a tapered surface inclined at an angle of 20 ° or less with respect to a horizontal plane toward the inner diameter direction is formed on the back side, and the height of the top having the tapered surface on the back side is a seal packing. A crawler belt sealing device characterized in that it is set to be lower than the back surface of the ring, and an annular groove having a lip portion is formed on the inner diameter surface side.
[0011]
The present invention is the crawler belt sealing device, wherein a horizontal flat surface is formed on a top portion having a tapered surface on the back side of the seal packing ring.
[0012]
The present invention is the crawler belt sealing device, wherein the seal packing ring has a concave portion formed in a front side of the seal packing ring and discontinuous in a radial direction thereof.
[0013]
[Action]
In the crawler belt sealing device of the present invention, the seal packing ring installed in the packing chamber has a tapered surface, and the top portion is gradually thicker toward the inner diameter side. As the pressure increases, the end face of the bush comes into contact with the top on the front side of the seal packing ring, and then the top with the tapered face provided on the back side abuts against the bottom of the packing chamber and is compressed in sequence to tighten. The pressure gradually increases. When a predetermined tightening pressure is reached, the seal packing ring is crushed. However, the surface pressure of the seal packing ring against the end surface of the bush in the present invention is lower at the center portion than at the edge portion, and the lubricating oil is stored in the center portion. This prevents running out of lubricating oil.
[0014]
Further, as described above, since the seal packing ring of the present invention is formed with a top portion having a tapered surface on both the front side and the rear side, even if the seal packing ring becomes thin due to wear, The tightening pressure does not decrease rapidly, and the sealing effect can be maintained.
[0015]
Further, when the seal packing ring has an annular groove having a lip on its inner diameter surface side, the deformation of the seal packing ring due to the (loading) compressive load applied to the top of both surfaces is absorbed by the annular groove, and the compressive load and The relationship with the deformation of the seal packing ring further approaches a proportional relationship. As described above, the seal packing ring of the present invention can prevent a sharp decrease in the tightening pressure as compared with the conventional seal packing ring even when it is worn (FIGS. 10A, 10B, and 10B). Refer to (c) the rate of change ΔP of each tightening pressure, where (a) in FIG. 10 is the seal packing ring of the present invention having an annular groove, (b) is the seal packing ring of the present invention having no annular groove, (c) ) Is a known seal packing ring).
[0016]
When the horizontal flat surface is formed on the top portion having the tapered surface on the back side of the seal packing ring, stability in mounting the seal packing ring in the packing chamber is high.
[0017]
If the seal packing ring has a concave part that is discontinuous in the radial direction on the front side, the contact between the bush and the seal surface will be discontinuous and the contact area will be reduced, so that the mirror surface will be formed by sliding. It is suitable for improving the sealing property because it easily holds a lubricant such as wax and grease.
[0018]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a partial sectional view of a crawler belt sealing device incorporating a seal packing ring according to one embodiment of the present invention. FIG. 2 is a partial sectional view of the seal packing ring according to one embodiment of the present invention. FIG. 4 is an enlarged sectional partial view of a seal packing ring according to one embodiment of the present invention.
[0019]
In FIG. 1, reference numeral 1 denotes a link pin for connecting adjacent links of the crawler belt, and outer links 2 are press-fitted and fixed to both ends of the link pin 1. This figure shows only one end. A packing chamber 2a is formed on the inner surface of the outer link 2, and the packing chamber 2a is formed as an annular groove in cooperation with the link pin 1. A bush 3 is loosely fitted on the outer periphery of the link pin 1, and an inner link 4 is fixed to the bush 3. A part of the bush 3 enters the packing chamber 2a, and a seal packing ring 5 is mounted in the packing chamber 2a. The seal packing ring 5 has elasticity and is excellent in abrasion resistance. In addition to a thermoplastic urethane resin, a urethane rubber or a urethane resin which may contain a sliding agent such as wax, fluororesin, and grease. It is made of synthetic rubber with the same high elasticity and high wear resistance.
[0020]
On the side of the front surface 6 of the seal packing ring 5 shown in FIGS. 2 and 4, a tapered surface having an inclination of 1 ° ≦ θ ≦ 20 °, preferably 2 ° ≦ θ ≦ 10 ° from a horizontal plane having the point A as a base point is provided. The thickness is gradually increased toward the inner diameter side and reaches the top portion 8. If θ is less than 1 °, the object of the present invention cannot be achieved, and if θ exceeds 20 °, it becomes difficult to set. On the side of the back surface 7 of the seal packing ring 5, a tapered surface having an inclination of 0 ° ≦ θ ′ ≦ 20 °, preferably 5 ° ≦ θ ≦ 15 ° and θ ′ ≦ θ from a horizontal plane with the point B as a base point is provided. The thickness is gradually increased toward the inner diameter side and reaches the top 9. In this embodiment, the top 9 is a flat horizontal surface from the viewpoint of stability when the seal packing ring 5 is set in the packing chamber 2a. The height of the top 9 is formed to be lower than the back 7 by Z. That is, point B is lower than top 9 (ie, closer to the front side).
[0021]
FIG. 3 is a partial sectional view of a seal packing ring according to another embodiment of the present invention. FIG. 5 is an enlarged sectional partial view of the seal packing ring of this embodiment.
[0022]
On the side of the front surface 6 of the seal packing ring 5 shown in FIGS. 3 and 5, a tapered surface having an inclination of 1 ° ≦ θ ≦ 25 °, preferably 2 ° ≦ θ ≦ 10 ° from a horizontal plane having the point A as a base point is provided. The thickness is gradually increased toward the inner diameter side and reaches the top portion 8. If θ is less than 1 °, the object of the present invention cannot be achieved, and if θ exceeds 25 °, it becomes difficult to set. On the side of the back surface 7 of the seal packing ring 5, a tapered surface having an inclination of 0 ° ≦ θ ′ ≦ 20 °, preferably 5 ° ≦ θ ≦ 15 ° and θ ′ ≦ θ from a horizontal plane with the point B as a base point is provided. The thickness is gradually increased toward the inner diameter side and reaches the top 9. In this embodiment, the top 9 is a flat horizontal surface from the viewpoint of stability when the seal packing ring 5 is set in the packing chamber 2a. The height of the top 9 is formed to be lower than the back 7 by Z. That is, point B is lower than top 9 (ie, closer to the front side). Further, in the seal packing ring 5 of the present embodiment, an annular groove 10 having lip portions 11 at both ends is formed on the inner diameter surface 12 side so as to be able to absorb deformation due to (tightening) compressive load on the top portion 8. Have been.
[0023]
The diameter of the inner hole of the seal packing ring 5 is set slightly larger than the outer diameter of the link pin 1. Further, the seal packing ring of the present invention is made thin, and in the illustrated example, the ratio X / Y between the thickness X and the radial length Y is set in a range of 0.3 to 1.0. .
[0024]
FIG. 6 is a front view of a seal packing ring according to still another embodiment of the present invention. On the front surface 6 side of the seal packing ring, there are provided concave portions 16 discontinuous in the radial direction, for example, various spot-shaped concave portions 16 such as a multi-line shape, a circle, a corner, and a point. The recess 16 preferably has a depth of, for example, about 0.1 mm, and in the case of a linear shape, preferably has a width of about 0.2 mm, and is provided so that the area of the recess is within 60% of the area of the front face 6 of the seal packing ring. Is preferred. FIG. 7 is a partial view of the seal packing ring of this embodiment viewed from the front side, and shows a representative example of a spot pattern. These recesses 16 can be formed by molding a seal packing ring with a mold having a convex portion, or by forming the front surface of the molded seal packing ring by electric discharge machining, sitat blasting, scraping, or the like.
[0025]
【The invention's effect】
As described above, the seal packing ring in the crawler belt sealing device of the present invention can prevent wear of the lubricating oil on the front face thereof and reduce wear. In addition, even when the seal packing ring is worn due to long-term use, the tightening pressure does not suddenly decrease with respect to the displacement of the thickness due to the wear. Therefore, it has become possible to provide a crawler belt sealing device that has a significantly longer life than conventional devices.
Further, it has become possible to provide a crawler belt sealing device which does not cause the "squeal" phenomenon and is more excellent in the above-mentioned effects.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view of a crawler belt sealing device incorporating a seal packing ring according to one embodiment of the present invention.
FIG. 2 is a partial sectional view of a seal packing ring according to one embodiment of the present invention.
FIG. 3 is a partial sectional view of a seal packing ring according to one embodiment of the present invention.
FIG. 4 is a partial cross-sectional view of a seal packing ring according to an embodiment of the present invention.
FIG. 5 is a partial cross-sectional view of a seal packing ring according to an embodiment of the present invention.
FIG. 6 is a view of a seal packing ring according to one embodiment of the present invention as viewed from the front side.
FIG. 7 is a partial view of the seal packing ring of one embodiment of the present invention as viewed from the front side, and shows a representative example of a spot pattern.
FIG. 8 is a partial sectional view of a conventional seal packing ring.
FIG. 9 is a partial sectional view of a conventional seal packing ring.
FIG. 10 is a drawing showing a relationship between a compression amount of a seal packing ring and a tightening pressure.
[Description of sign]
REFERENCE SIGNS LIST 1 link pin 2 outer link 2 a packing chamber 3 bush 4 inner link 5 seal packing ring 6 front of seal packing ring 7 back of seal packing ring 8 top of seal packing ring front 9 top 10 of seal packing ring rear 10 annular groove 16 Recess

Claims (4)

An outer link having an annular packing chamber formed inside is fixed to both ends of the link pin, and a bush whose end can be fitted into the packing chamber is inserted on the link pin, and the inner link is fixed on the bush. In a crawler belt sealing device having a seal packing ring mounted in a link packing chamber,
The seal packing ring has, on its front side, a top portion having a taper surface inclined at 1 ° to 20 ° with respect to a horizontal plane toward the inner diameter direction, and has a rear side within 20 ° with respect to the horizontal surface toward the inner diameter direction. A crest having a tapered surface having a slope of the inclination is formed, and the height of the crest having the tapered surface on the back side is set to be lower than the back surface of the seal packing ring. Sealing device. An outer link having an annular packing chamber formed inside is fixed to both ends of the link pin, and a bush whose end can be fitted into the packing chamber is inserted on the link pin, and the inner link is fixed on the bush. In a crawler belt sealing device having a seal packing ring mounted in a link packing chamber,
The seal packing ring has, on its front side, a top portion having a tapered surface inclined at 1 ° to 25 ° with respect to a horizontal plane toward the inner diameter direction, and on its back side within 20 ° with respect to the horizontal surface toward the inner diameter direction. An annular groove having a tapered surface with an inclination of is formed, the height of the top having the tapered surface on the back side is set to be lower than the back surface of the seal packing ring, and a lip portion on the inner diameter surface side. Wherein the crawler belt sealing device is formed. 3. The crawler belt sealing device according to claim 1, wherein a horizontal flat surface is formed on the top having the tapered surface on the back side. The crawler belt sealing device according to any one of claims 1 to 3, wherein a concave portion that is discontinuous in a radial direction is formed on a front side of the seal packing ring.

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