JP3714637B2 - Upper rolling structure of tracked vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an overturning structure of a tracked vehicle in a construction machine such as a hydraulic excavator and a bulldozer.
[0002]
[Prior art]
A conventional upper wheel structure in a tracked vehicle will be described by taking a conventional hydraulic excavator as an example.
First, the excavator 20 will be described with reference to FIG.
The center frame 2 of the lower traveling body 21 is fastened to the left and right crawler frames 3, and a traveling motor 25 attached to the crawler frame 3 allows the lower traveling body 21 to travel forward and backward. An upper swing body 23 is attached to the upper portion of the lower traveling body 21 via a swing circle 22 and can be turned by a turning motor (not shown). A work machine 30, a machine cab 26, an operator cabin 27, and a counterweight 28 are attached to the upper swing body 23.
The work machine 30 includes a boom 31, an arm 33, a bucket 35, and a plurality of hydraulic cylinders 32, 34, and 36, and performs soil excavation work.
[0003]
Next, the suspension device of the excavator 20 will be described with reference to FIG.
An idler wheel 5 and a drive wheel 4 are disposed before and after the crawler frame 3, and a crawler belt 7 is wound between the idler wheel 5 and the drive wheel 4, and the crawler belt 7 is fixed to the crawler frame 3. It is supported by the lower roller 8 and the upper roller 10. The driving wheel 4 is driven by a traveling motor (not shown), and the sprocket 6 fixed to the driving wheel 4 and the crawler belt 7 are engaged with each other so that the lower traveling body 21 of the excavator 20 can travel forward and backward.
[0004]
Next, the structure of the conventional upper roller 10 will be described with reference to FIG.
The roller 13 is rotatably fitted to a fixed shaft 12 protruding from the upper portion of the stay 11, a thrust washer 14 is fixed to the outer end of the fixed shaft 12 with a bolt 15, and a bolt is attached to the outer end of the roller 13. 17, the cover 16 is fixedly installed to face the thrust washer 14, and the seal 19 and the seal support 9 are disposed inside the roller 13, and the fixed shaft 12 takes a radial load from the roller 13. more thrust load, so that the responsible thrust washer 14 disposed on the rolling wheels 13 and the cover 16 between fixed to the outer end of the fixed shaft 12.
[0005]
Above the structure of the conventional carrier rollers 10, since the position of the line of action of a large radial load applied to the roller 13 from the track 7, the position of the stay 11 for supporting the radial load is larger offset, shaft 12 and stays 11 is subject to a large shearing force and bending moment, and problems such as bending of the shaft 12 , cutting and bending of the stay 11 are likely to occur. To prevent this trouble, the diameter of the shaft 12 is increased or a high strength material is used. There is a problem that the use of the stay 11 and the stay 11 need to have a sturdy structure increase the cost.
[0006]
For this reason, for example, Japanese Utility Model Publication No. 2-10065 is disclosed as an improvement on the conventional structure of the upper roller 10 . According to the publication, as shown in FIG. 7, the upper roller 40 has a rotating shaft 42 fitted into an upper end portion of a stay 41 via a bearing 45, and a pair of rollers 43 are fixed to both ends of the rotating shaft 42. In addition, the seals 49 are arranged on both sides of the upper end portion of the stay 41 and between the rollers 43 on both sides of the upper end portion of the stay 41 to reduce the offset load acting on the stay 41 and the rotating shaft 42, thereby reducing the shearing force, A technique for reducing the bending moment is described.
[0007]
[Problems to be solved by the invention]
However, in the above Japanese Utility Model Publication No. 2-10065, since the radial load acting on the roller 43 is always downward, the bearing 45 disposed between the rotating shaft 42 and the stay 41 is only a part of the lower side. There is a problem that the sliding surface of this part is significantly worn and the life is short.
[0008]
The present invention pays attention to the above-mentioned conventional problems, and a shaft that rotatably supports the roller is fixed to the stay, and the bearing circumference is uniformly loaded with the rotation of the roller, so that the bearing life is greatly improved. An object is to provide an upper roller structure.
[0009]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, an upper rolling structure of a tracked vehicle according to the present invention is an overturning of a tracked vehicle that is erected via a stay on a crawler frame of a lower traveling body of the tracked vehicle. It is a ring structure, and is interposed between the shaft fixed to the upper portion of the stay, a pair of rollers rotatably attached to both ends of the shaft via bearings, and the stay and the pair of rollers. A floating seal is provided, and the stay and the bearing are slidably contacted .
The shaft is fixed to the stay by a press-fitting means.
Further, the shaft is fixed to the stay by means of means for reducing a slit provided on the stay side.
[0010]
[Action]
According to the above configuration, since the bearings are housed in the rotatably disposed rollers at both ends of the shaft fixed to the stay, the circumference of the bearing is uniformly loaded with the rotation of the rollers. The wear due to sliding is not concentrated in one place, and the bearing life is greatly improved.
In addition, since the shaft is fixed to the stay by press-fitting, the structure is simple and compact.
Further, since the shaft is fixed to the stay by reducing the slit provided on the stay side, it is not necessary to precisely process the outer peripheral fixing portion of the shaft and the shaft hole of the stay, and the assembly is also simplified.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a specific example of the upper roller structure of a tracked vehicle according to the present invention will be described with reference to the drawings. Parts common to FIGS. 4 and 5 will be described with the same reference numerals.
[0012]
A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a longitudinal sectional view of an upper roller 50 of the first embodiment. 2 is a cross-sectional view taken along line MM in FIG.
First, the shaft 52 shown in FIG. 1 is fixed by press-fitting the central portion 52a into the shaft hole 51a in the upper portion of the stay 51. A flanged bearing 55 is fixed in the hole 53a of the roller 53 by press-fitting. The roller 53 through the inner surface 55a of the bearing 55 is fitted rotatably to the shaft 52, between the inner surface 55a of the shaft 52 and the bearing 55 is adapted to slide Yes lubricating oil put.
The outer side surface 55b of the flange of the bearing 55 and the upper side surface 51b of the stay 51 are in contact with each other so as to be slidable and receive an inward thrust load acting on the roller 53 with this contact surface. .
[0013]
The outer periphery of the thrust bearing 54 is fixed by press-fitting in the hole 53 b of the roller 53, and a thrust washer 56 is fixed by a bolt 57 at the outer end of the shaft 52.
The outer side surface 54a of the thrust bearing 54 and the inner side surface 56a of the thrust washer 56 are slidably contacted. The abutting surface receives an outward thrust load acting on the roller 53.
A cover 58 is fixed to the outer surface of the roller 53 with a bolt 60 through a seal 59, and the cover 58 forms a lubricating oil reservoir 62 together with a hole 61 of the roller 53.
A floating seal 65 composed of an O-ring 63 and a seal ring 64 is interposed between the upper side surface of the stay 51 and the inner side surface of the roller 53, and is rotationally sealed so as not to leak lubricating oil to the outside. The stay 51 is fixed to the crawler frame 3 with bolts 67.
[0014]
Next, a plug 66 is provided on the upper portion 51c of the stay 51 shown in FIG. 2, so that the lubricating oil can be supplied to the oil reservoir 62 through the holes 52b and 52c of the shaft 52 and the hole 56b of the thrust washer 56. Yes.
[0015]
According to the first embodiment, since the bearings 55 are housed in the rollers 53 rotatably disposed at both ends of the shaft 52 press-fitted into the stay 51, the bearings are rotated as the rollers 53 rotate. Since the circumference of 55 receives the load evenly, the wear due to sliding is not concentrated in one place, and the bearing life is greatly improved. Further, since the shaft 52 is press-fitted into the stay 51, the structure is simple and compact.
[0016]
Next, a second embodiment of the present invention will be described with reference to FIG.
The upper roller has the same structure as that of FIG. 1 of the first embodiment, and the description thereof is omitted here. FIG. 3 shows a fixing portion between the shaft 52A and the stay 51A, and corresponds to FIG. 2 of the first embodiment. A slit 51f is provided in the upper part 51d of the stay 51A from the shaft hole 51e, and flanges 51g and 51h are provided above and below the slit 51f. The shaft 52A is fixed to the stay 51A by fastening the flanges 51g and 51h with bolts 64.
[0017]
According to the second embodiment, since the shaft 52A is fixed to the stay 51A by the bolt 64, the outer peripheral fixing portion of the shaft 52A and the shaft hole 51e of the stay 51A do not need to be precisely processed, and assembly is also possible. It will be easy.
[0018]
【The invention's effect】
As described above, according to the upper rolling structure of the tracked vehicle of the present invention, the bearings are housed in the rollers disposed rotatably at both ends of the shaft fixed to the stay. As the roller rotates, the circumference of the bearing receives a load evenly, so wear due to sliding is not biased in one place, and the life of the bearing is extended and durability is improved.
[0019]
Further, by fixing the shaft fixed to the stay to the stay by bolting, it is not necessary to precisely process the shaft and the shaft hole of the stay, and assembling is simplified and the cost is reduced.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a first embodiment of an upper roller structure of a tracked vehicle according to the present invention.
FIG. 2 is a cross-sectional view taken along the line MM in FIG.
FIG. 3 is a view showing a fixing portion between a shaft and a stay in a second embodiment of the upper rolling structure of the tracked vehicle of the present invention.
FIG. 4 is a side view of a conventional hydraulic excavator.
FIG. 5 is a side view of a conventional suspension device for a hydraulic excavator.
FIG. 6 is a view showing a first example of a conventional overturning structure of a hydraulic excavator.
FIG. 7 is a diagram showing a second example of a conventional overturning structure of a hydraulic excavator.
[Explanation of symbols]
2 ... center frame, 3 ... crawler frame, 4 ... driving wheel, 5 ... idle wheel, 6 ... sprocket, 7 ... crawler belt, 8 ... downwheel, 20 ... hydraulic excavator, 21 ... lower traveling body, 23 ... upper turning body , 30 ... working machine, 50 ... upper wheel, 51, 51A ... stay, 51f ... slit, 52 , 52A ... shaft , 53 ... roller, 55 ... bearing, 54 ... thrust bearing, 56 ... thrust washer, 65 ... seal.

Claims (3)

An upper rolling structure of a tracked vehicle standing on a crawler frame (3) of a lower traveling body (21) of a tracked vehicle via a stay (51), and above the stay (51) A fixed shaft (52), a pair of rollers (53, 53) rotatably attached to both ends of the shaft (52) via bearings (55), the stay (51) and the pair of rollers (53, 53) and a floating seal (65) interposed between the stay (51) and the bearing (55) so as to be slidable . Upper roller structure.   The upper rolling structure of a tracked vehicle according to claim 1, wherein the shaft (52) is fixed to the stay (51) by press-fitting means.   The upper rolling structure of a tracked vehicle according to claim 1, wherein the shaft (52) is fixed to the stay (51) by means for reducing a slit (51f) provided on the stay (51) side. .

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