JP2000179696A - Seal structure for crawler belt connecting pin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure required sealing performance by preventing a lowering of wear resistance caused by sliding heat generation of a sealing face due to becoming an unlubricated state. SOLUTION: An annular sealing member 10 is mounted around an axis of a conencting pin 1, in the state of being held to a crawler belt link 2. One side face 12 of the sealing member 10 is formed as an annular sealing face to which an annular bush 4 is pressed in sliding contact, and a lubricant such as grease is filled. One side face 12 of annular shape to be the sealing face is provided with a plurality of oil sump recessed parts 13 radially at equal pitch. When the oil film break of grease occurs at one side face 12, grease stored in the oil sump recessed parts 13 ensures required lubricating ability. Required surface pressure at one side face 12 of the sealing member 10 is therefore maintained, and infiltration of dust is prevented to ensure required sealing performance so as to maintain required wear resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an undercarriage endless track in a power shovel or the like of a heavy construction machine, that is, a seal structure of a connecting pin for connecting crawler tracks constituting a track.

[0002]

2. Description of the Related Art FIG. 3 is a sectional view showing a seal structure around an axis of a connecting pin 1 for connecting crawler belt links forming a caterpillar or the like. A crawler belt link 2 is connected via a connecting pin 1, and an annular seal member 3 mounted between the two members is pressed from outside by an annular bush 4 and held at a fixed position. In this case, an annular spacer may be interposed between the connection pin 1 and the inner and outer circumferences of the seal member 3. Since the bush 4 slides in contact with the outer surface 3a on one side of the seal member 3, the space between the bush 4 and the outer surface 3a on one side is used as a sealing surface, and lubricating oil such as grease is filled therein. As a material of the seal member 3, for example, high hardness urethane rubber is used.

In such a conventional crawler track connecting pin seal structure, a high load due to the weight of the body or driving force acts on the bush 4 during the operation of the heavy equipment. The oil film of the grease may be cut off on the outer surface 3a on one side, which is the sealing surface of the sealing member 3, and the lubricating function may be reduced. When the bush 4 slides in a non-lubricated state due to oil film shortage, one side outer surface 3a of the seal member 3
A considerable pressing force and frictional force act on the surface, and the wear resistance is reduced due to heat generation and wear. As a result, there is a problem that the surface pressure of the outer surface 3a on one side of the seal member 3, which is the seal surface, is reduced and muddy water or dust enters there, and the required sealing function as the seal member 3 cannot be maintained.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to prevent abrasion of a sealing surface in an unlubricated state due to oil film shortage,
It is an object of the present invention to provide a crawler belt connecting pin seal structure capable of ensuring required sealing properties.

[0005]

A crawler belt link pin sealing structure according to the present invention is such that a crawler belt link is connected via a link pin, and an annular seal member is held in an annular storage portion provided on the crawler belt link. The crawler belt link and the connecting pin are attached by the seal member by being mounted around the axis of the connecting pin in a state where the seal member is further pressed against an annular bush against one side surface of the sealing member so as to be slidably contactable. In order to secure a required sealing property between one side, one side of the sealing member is formed as an annular sealing surface, and a lubricant is filled between the one side and the sliding contact surface of the bush, and the one side formed as the sealing surface A plurality of oil storage recesses are provided radially, and when an oil film breaks, a required lubricating property is ensured by a lubricant stored in the oil storage recess, so that a required surface pressure on one side surface is obtained. It has secured the required sealing against dust intrusion while maintaining.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a crawler belt connecting pin sealing structure according to the present invention will be described in detail with reference to the drawings. The same reference numerals are given to the same or similar members as those shown in the conventional structure of FIG.

FIGS. 1 and 2 are a sectional view showing a seal structure according to an embodiment of the present invention and a plan view showing a part of a seal member alone. A crawler belt link 2 is connected via a connecting pin 1, and an annular seal member 10 is mounted around a pin axis as a dust seal for preventing dust from entering. The seal member 10 is housed in a state where the inner surface 11 on one side is in contact with the wall surface 2a of the annular storage portion provided on the crawler belt link 2 and is stored by pressing the annular bush 4 against the outer surface 12 on the other side from the outside. Is held in the department. The other outer surface 12 on the other side of the seal member 10 is formed as a seal surface, and the inner surface of the bush 4 rotating around the axis of the connecting pin 1 is brought into close contact with the sliding surface. When the bush 4 is assembled, the space between the bush 4 and the other outer surface 12 of the seal member 10 with which the bush 4 slides is filled with lubricating oil such as grease. As shown in the conventional example, as the material of the seal member 10, a high-hardness urethane rubber or the like can be used.

As shown in FIG. 2, on the other outer surface 12 serving as a sealing surface of the sealing member 10 with which the bush 4 slides, a recessed oil storage recess is preferably formed at a plurality of locations, preferably at an even pitch, over the entire circumference. 13 are formed radially.

In the present embodiment, the following effects can be obtained by configuring the seal member 10 as described above.

During the operation of the heavy equipment, a high load due to the weight of the body and the driving force acts on the bush 4. Grease, which is a lubricant, is supplied to the outer surface 12 on the other side, which is the sealing surface of the seal member 10, and the grease is also supplied to the oil storage recesses 13 provided at a plurality of locations radially and stay there. Bush 4
Is applied to the other outer surface 12 which is the sealing surface of the sealing member 10. If the grease on the other outer surface 12 of the seal member 10 is used over time under such a high load action, the oil film may be broken.

In the seal member 10, even if the oil film runs out on the other outer surface 12 on the other side of the sealing surface, the grease accumulated and stored in the oil storage recess 13 performs a lubricating function with the bush 4. With seal member 10 and bush 4
Abrasion and heat generation occurring between them can be minimized, and a required sealing function can be secured. Also,
By ensuring such a lubricating function, a required surface pressure between the bush 4 and the bush 4 can be maintained. As a result, it is possible to prevent muddy water and dust from entering the other outer surface 12, which is the sealing surface of the sealing member 10, and to maintain required durability against abrasion and the like.

[0012]

According to the seal structure of the crawler belt connecting pin according to the present invention, an annular sealing member is mounted around the axis of the connecting pin while being held by the crawler belt link. In the structure in which the bush is pressed and slid, a plurality of oil storage recesses are radially provided on one side surface of the seal member with which the bush slides, so that even if the oil film breaks on one side surface, the oil storage recess is provided. The required lubricating property is ensured by the lubricant stored in the cylinder, so that the required surface pressure on one side can be maintained, the required sealing performance against dust infiltration can be maintained, and the wear resistance can be maintained. .

[Brief description of the drawings]

FIG. 1 is an assembled sectional view showing an embodiment of a crawler belt connecting pin sealing structure according to the present invention.

FIG. 2 is a plan view showing a part of a seal member according to the embodiment.

FIG. 3 is an assembled sectional view showing a conventional crawler belt connecting pin sealing structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crawler belt connecting pin 2 Crawler belt link member 4 Bush 10 Seal member 12 Other outer surface of sealing surface 13 Oil storage recess

Claims (1)

[Claims] 1. A crawler belt link is connected via a connecting pin, and is mounted around an axis of the connecting pin in a state where an annular seal member is held in an annular storage portion provided on the crawler belt link. A seal structure in which a required sealing property between the crawler belt link and the connection pin is secured by a seal member by pressing an annular bush against one side surface and slidably mounting the connection bush around the axis of the connection pin. One side is formed as an annular sealing surface, and lubricant is filled between the sliding surface of the bush and a plurality of oil storage recesses are provided radially on one side formed as the sealing surface, so that the oil film breaks. By ensuring the required lubricity with the lubricant stored in the oil storage recess when it occurs,
A crawler track connecting pin seal structure, wherein a required surface pressure on one side is maintained and a required sealing property against dust intrusion is secured.