JPH0976954A - Upper roller structure of track type vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an upper roller structure of a track type vehicle to greatly improve the service life of a bearing by evenly receiving the load by the circumference of the bearing as a miller is rotated. SOLUTION: An upper miller structure consists of a fixed shaft 52 which is erected on a crawler frame 3 of a lower traveling body of a track type vehicle through a stay 51 and fixed to this stay 51, and a pair of rollers 53, 53 which are rotatably fitted to each end part of the fixed shaft 52 through a bearing 55.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an upper wheel structure for a tracked vehicle in a construction machine such as a hydraulic excavator and a bulldozer.

[0002]

2. Description of the Related Art A conventional upper wheel structure in a tracked vehicle will be described by taking a conventional hydraulic excavator as an example. First,
The hydraulic 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 the traveling motor 4 mounted on the crawler frame 3 allows the lower traveling body 21 to travel back and forth. An upper revolving structure 23 is mounted on the upper part of the lower traveling structure 21 via a swing circle 22, and can be revolved by a revolving 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 is composed of a boom 31, an arm 33, a bucket 35, and a plurality of hydraulic cylinders 32, 34, 36, and is adapted to excavate earth and sand.

Next, a suspension device for the hydraulic excavator 20 will be described with reference to FIG. An idle wheel 5 and a drive wheel 4 are arranged in front of and behind 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 wheel 10. The drive wheels 4 are driven by a traveling motor (not shown), and the sprocket 6 fixedly mounted on the drive wheels 4 and the crawler belt 7 are engaged with each other to allow the lower traveling body 21 of the hydraulic excavator 20 to travel back and forth.

Next, the structure of the conventional upper roller 10 is shown in FIG.
This will be described below. 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. A cover 16 is fixed to the thrust washer 14 at 17, and a seal 19 and a seal support 9 are arranged inside the roller 13. The fixed shaft 12 receives a radial load from the roller 13, The thrust load of the above is supported by a thrust washer 14 which is fixed to the outer end of the fixed shaft 12 and is arranged between the upper roller 13 and the cover 16.

In the above-mentioned conventional structure of the upper roller, the position of the line of action of a large radial load acting on the roller from the crawler belt,
Since the position of the stay that supports the radial load is largely offset, large shearing force and bending moment are applied to the shaft and stay, and problems such as bending of the shaft, cutting damage and bending of the stay are likely to occur, and prevent this trouble. In order to increase the diameter of the shaft, use high strength material,
In addition, there is a problem in that the stay needs to have a sturdy structure and the cost increases.

[0006] Therefore, in order to solve the above-mentioned conventional problems of the structure of the upper wheels, for example, Japanese Utility Model 2-100.
No. 65 is known. According to the publication, as shown in FIG. 7, the upper roller 40 has a rotary shaft 42 fitted and inserted into an upper end portion of a stay 41 via a bearing 45, and a pair of rollers 43 is fixed to both end portions of the rotary shaft 42. And a seal 49 is provided between both sides of the upper end of the stay 41 and the roller 43 to reduce the offset load acting on the stay 41 and the rotary shaft 42, thereby reducing the shearing force. Techniques for reducing bending moments are described.

[0007]

However, in the above-mentioned Japanese Utility Model Publication No. 2-1-10065, since the radial load acting on the roller is always downward, the bearing arranged between the rotary shaft and the stay is on the lower side. Since only a part of the above will bear the load, there is a problem that the sliding surface of this part is significantly worn and the life is short.

Focusing on the above-mentioned conventional problems, the present invention adopts a structure in which a fixed shaft for rotatably supporting a roller is fixed to a stay, and the circumference of the bearing receives a load evenly as the roller rotates, so that the bearing life is increased. It is an object of the present invention to provide an upper wheel structure that is significantly improved.

[0009]

In order to achieve the above object, an upper wheel structure for a tracked vehicle according to the present invention is provided with a stay 5 on a crawler frame 3 of a lower traveling body 21 of the tracked vehicle.
1 is an upper wheel structure of a tracked vehicle that stands upright through 1.
Fixed shaft 52 fixed to the center of the upper end of the stay 51
And a pair of rollers 53 rotatably attached to both ends of the fixed shaft 52 via bearings 55.

[0010]

According to the above construction, since the bearings are housed in the rollers rotatably arranged at both ends of the fixed shaft fixed to the stay, the circumference of the bearing is evenly distributed as the rollers rotate. Since the load is applied, wear due to sliding is not concentrated in one place, and the life of the bearing is greatly improved.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A specific example of an upper wheel structure of a track-mounted vehicle according to the present invention will be described below with reference to the drawings. It should be noted that parts common to those in FIGS.

A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a vertical sectional view of the upper roller 50 of the first embodiment. FIG. 2 is a sectional view taken along line MM of FIG. First, the fixed shaft 52 shown in FIG. 1 is fixed by press fitting the central portion 52a into the shaft hole 51a at the upper end portion of the stay 51. A flanged bearing 55 is press-fitted into the hole 53a of the roller 53 to be fixed thereto. The roller 53 is rotatably fitted to the fixed shaft 52 via the inner surface 55a of the bearing 55, and the fixed shaft 52 and the bearing 5
The inner surface 55a of 5 is filled with lubricating oil so that it can slide. The outer surface 55b of the collar of the bearing 55 and the stay 51
The side surface 51b of the upper end of the
The abutment surface receives the inward thrust load acting on the roller 53.

The outer periphery of the thrust bearing 54 is press-fitted and fixed to the hole 53b of the roller 53, and the thrust washer 56 is fixed to the outer end of the fixed shaft 52 with a bolt 57. The outer side surface 54a of the thrust bearing 54 and the inner side surface 56a of the thrust washer 56 are in slidable contact with each other.
The contact surface receives a thrust load acting on the roller 53 toward the outside. A cover 58 is fixed to the outer surface of the roller 53 with a bolt 60 via a seal 59, and the cover 58 forms an oil reservoir 62 of lubricating oil together with a hole 61 of the roller 53. Between the side surface of the upper end of the stay 51 and the inner side surface of the roller 53, a floating seal 65 including an O-ring 63 and a seal ring 64.
The rotary seal is provided so that the lubricating oil does not leak outside. The stay 51 is fixed to the crawler frame 3 with bolts 67.

Next, the upper end portion 51 of the stay 51 shown in FIG.
c is provided with a plug 66, and the hole 52b of the fixed shaft 52,
The lubricating oil can be supplied to the oil sump 62 through the hole 52b of the thrust washer 56 and the hole 52b.

According to such a first embodiment, the stay 5
Since the bearings 55 are internally provided in the rollers 53 rotatably arranged at both ends of the fixed shaft 52 press-fitted in 1, the circumference of the bearings 55 is evenly loaded with the rotation of the rollers 53. Wear due to sliding is not concentrated in one place, and bearing life is greatly improved. Further, since the fixed shaft 52 is press-fitted into the stay 51, the structure is simple and compact.

Next, a second embodiment of the present invention will be described with reference to FIG. The upper wheel has the same structure as that of the first embodiment shown in FIG. 1, and a description thereof will be omitted here. The fixing portion of the fixed shaft 52A and the stay 51A shown in FIG. 3 is shown, and corresponds to FIG. 2 of the first embodiment. At the upper end 51d of the stay 51A,
A slit 51f is provided outward from the shaft hole 51e, and flanges 51g and 51h are provided above and below the slit 51f.
Is provided. By fixing the flanges 51g and 51h with bolts 64, the fixed shaft 52A is attached to the stay 51A.
It is fixed to.

According to such a second embodiment, the fixed shaft 5
Since 2A is fixed to the stay 51A by the bolts 64, it is not necessary to perform precision machining on the outer peripheral fixing portion of the fixed shaft 52A and the shaft hole 51e of the stay 51A, and the assembly is also simple.

[0018]

As described above, according to the upper wheel structure of the tracked vehicle of the present invention, the bearings are provided to the rollers rotatably arranged at both ends of the fixed shaft fixed to the stay. Since the bearing is internally provided, the load is evenly applied to the circumference of the bearing as the roller rotates, and wear due to sliding is not concentrated in one place, extending the life of the bearing and improving its durability.

Further, by fixing the fixed shaft fixed to the stay to the stay by bolting, it is not necessary to precisely machine the fixed shaft and the shaft hole of the stay, and the assembly is simple and the cost is low.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a first embodiment of the upper wheel structure of a tracked vehicle of the present invention.

FIG. 2 is a sectional view taken along line MM in FIG.

FIG. 3 is a diagram showing a fixed portion between a fixed shaft and a stay of a second embodiment of the upper wheel 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 suspension device for a conventional hydraulic excavator.

FIG. 6 is a diagram showing a first example of a conventional upper wheel structure of a hydraulic excavator.

FIG. 7 is a diagram showing a second example of a conventional upper wheel structure of a hydraulic excavator.

[Explanation of symbols]

2 ... Center frame, 3 ... Crawler frame, 4 ... Drive wheel, 5 ... Idler wheel, 6 ... Sprocket, 7 ... Crawler belt, 8 ... Lower wheel, 20 ... Hydraulic excavator, 21 ... Undercarriage, 23 ...
Upper revolving structure, 30 ... Working machine, 50 ... Upper wheel, 51, 51
A ... Stay, 52, 52A ... Fixed shaft, 53 ... Roller, 5
5 ... Bearing, 54 ... Thrust bearing, 56 ... Thrust washer, 65 ... Seal.

Claims (1)

[Claims] 1. An upper wheel structure for a tracked vehicle in which a stay (51) is erected on a crawler frame (3) of a lower traveling body (21) of the tracked vehicle via a stay (51). The fixed shaft (52) fixed to the center of the upper end of the roller, and a pair of rollers (5) rotatably attached to both ends of the fixed shaft (52) via bearings (55).
3,53), and the upper wheel structure of a tracked vehicle.