JPH04317877A - Lower running body of crawler vehicle - Google Patents

Abstract

PURPOSE:To suppress the early wear of the sliding surface of an idler bearing rotatably supporting an idler, in the lower running body of a crawler vehicle, prevent a yoke from being shaken to an idler bracket, and improve the running property of the crawler vehicle over a long period. CONSTITUTION:Each arm part 32 of a yoke 31 has each plate vertical oscillation preventing projection 36 and each plate horizontal oscillation preventing projection 37 each of which is situated closer to the base end part and vertically protruded, and the horizontal oscillation preventing projection 37 and the vertical oscillating preventing projection 36 are brought into sliding contact with an upper guide plate 7A and a lower guide plate 7B in each guide part 7 of an idler bracket 6 to share the load acting on an idler bearing.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an undercarriage of a tracked vehicle, such as a hydraulic excavator, which is driven by a crawler track, and particularly relates to an improvement in an idler support structure.

0002

2. Description of the Related Art FIGS. 5 to 12 show a hydraulic excavator as an example of a conventional tracked vehicle.

In the figure, reference numeral 1 denotes an undercarriage, and numeral 2 denotes an upper revolving body rotatably mounted on a track frame 3 of the undercarriage 1. A working device 4 is provided at the front of the upper revolving body 2. is installed so that it can be tilted up and down.

[0004] The track frame 3 of the lower traveling body 1 includes a center frame (not shown) located at the center and supporting the upper rotating body 2, and a center frame (not shown) extending in the front and back direction on both left and right sides of the center frame. The side frames 5 are generally constructed from a pair of side frames 5 (only one shown), and each side frame 5 is made of a cylinder having a substantially pentagonal cross section extending in the front-rear direction by joining elongated plates by welding or the like. It is formed as a shaped body.

Reference numeral 6 indicates an idler bracket provided at one end of each side frame 5, and each idler bracket 6 has a substantially square cross section as shown in FIG.
Left and right bottom plates 6A, 6A are integrally formed by extending from the bottom plate 5A of the side frame 5, and left and right side plates 6B, 6B whose lower ends are respectively fixed to the respective bottom plates 6A and extend vertically.
, an upper plate 6C integrally formed on the upper end side of each side plate 6B, and a partition plate 6 to which the upper plate 6C and each side plate 6B are fixed, and partitions between the idler bracket 6 and the side frame 5.
It is composed of D. Here, the upper plate 6C has a substantially U-shaped notch in the center of one end side to accommodate an idler 9, which will be described later, and the partition plate 6D has a rod 19 of a track tension adjustment device 15, which will be described later. Insertion hole 6E to be inserted
is provided.

7, 7 are each side plate 6 of the idler bracket 6.
A pair of guide parts 7 are shown projecting inward from B, and each guide part 7 faces each other in the left and right direction with a predetermined interval above and below, and extends from the partition plate 6D to each side plate 6B in parallel with the bottom plate 6A etc. Consists of a pair of left and right upper guide plates 7A, 7A and lower guide plates 7B, 7B extending to the distal end side of each guide plate 7A.
, 7B are fixed to each side plate 6B and partition plate 6D. Further, each upper guide plate 7A and each lower guide plate 7B are connected to the upper plate 6 by a pair of reinforcing plates 7C, 7C, 7D, and 7D, respectively.
C. It is joined to the bottom plate 6A at the top and bottom, forming a solid board structure.

Reference numeral 8 indicates a yoke disposed within the idler bracket 6 of each side frame 5, and the yoke 8 has a pair of arm portions 8A, 8A that branch left and right and extend in parallel. The tip of the portion 8A is a fastening portion 8C in which two bolt holes 8B, 8B are bored vertically apart. Further, each arm portion 8A is integrated at a connecting portion 8D on the proximal end side, and the yoke 8 as a whole has a substantially U-shape. The connecting portion 8D is provided with a rod connecting portion 8E located at the center in the left-right direction to which a rod 19 of a crawler belt tension adjustment device 15, which will be described later, is fixed.

Reference numeral 9 designates an idler as an idler wheel located at one end of each side frame 5 and slidably supported within the idler bracket 6 via a yoke 8. 9A of large diameter parts, and 9A of large diameter parts.
An annular edging portion 9B is provided at both ends of the rim and has a smaller diameter than the large diameter portion 9A, and a rotating shaft 9C serving as a center of rotation is provided on the inner circumferential side, and an annular edge portion 9B is formed around the rotating shaft 9C. An integrally formed thick cylindrical boss portion 9D is provided.

10, 10 is the rotating shaft 9C of the idler 9
Left and right idler bearings are shown attached to the distal end side of the yoke 8 in order to rotatably support the yoke 8.
It is fastened to the fastening portion 8C by each bolt 10A inserted into each bolt hole 8B. Each idler bearing 10 is inserted into the guide portion 7 of the idler bracket 6 while being fixed to the yoke 8, and each of the upper and lower sliding surfaces 10
B is adapted to be slidably displaced along the upper guide plates 7A, 7A and the lower guide plates 7B, 7B of each guide portion 7. Here, as shown in FIG. 11, the yoke 8 is loosely fitted into each guide portion 7 without contacting the upper and lower guide plates 7A, 7B, etc., and the idler bearing 10 is fixed to the fastening portion 8C.
As shown in FIG. 12, the idler slides on the upper guide plates 7A, 7A and the lower guide plates 7B, 7B via the upper and lower sliding surfaces 10B to prevent the idler 9 from shaking in the vertical direction. It has become.

Reference numeral 11 denotes a drive wheel provided on the other end side of each side frame 5. The drive wheel 11 is rotationally driven by a hydraulic motor (not shown) or the like as a traveling actuator, and drives a crawler track 12, which will be described later. It is supposed to be done.

Reference numeral 12 indicates a crawler belt wound between the idler 9 and the driving wheel 11. The crawler belt 12 is guided by upper rollers 13, 13 on the upper side of the side frame 5, and lowers on the lower side of the side frame 5. The lower traveling body 1 is guided by rollers 14, 14, . Here, each upper roller 13 and each lower roller 14 are connected to the side frame 5.
The rollers 13 and 14 are rotatably provided on the upper and lower sides of the rollers 13 and 14 to prevent the crawler belt 12 from coming into contact with the side frame 5.

Reference numeral 15 indicates a crawler belt tension adjustment device provided in each side frame 5, and the adjustment device 15 includes a cylinder 16 formed in the shape of a cylinder with a bottom and having a spring receiving portion 16A on the outer peripheral side; A rod cover 17 that covers one end of the cylinder 16 and slidably supports a rod 19 to be described later, and a rod cover 17 that protrudes in the axial direction from both ends of the cylinder 16, and a piston is inserted into the cylinder 16 between the opposing ends. rods 18 and 19 defining a grease chamber (both not shown) through the rods 18 and 19, a spring receiver 21 inserted into the protruding end of the rod 18 and secured by a nut 20, and a spring receiver of the cylinder 16. 16A and the spring receiver 21, and the spring receiver 21
By pressing the rod 18 against the support plate 25 which will be described later.
a spring 22 that is always biased in the extension direction; a cylindrical cover 23 whose other end is fixed to a support plate 25 and which extends in the axial direction within the side frame 5 so as to surround the spring 22; and a rod. The rod 1 is located around the cylinder 18 and is fixed to the bottom side of the cylinder 16, and the rod 1
It is generally composed of a cylindrical stopper 24 that regulates the most contracted position of 8. The adjusting device 15 is connected to a spring 22.
The rod 18 is always urged in the direction of extension, and the rod 19
, by constantly pressing the idler 9 in the direction of arrow A (the length direction of the side frame 3) via the yoke 8, etc.
The tension of the crawler belt 12 is adjusted.

Reference numeral 25 indicates a support plate fixed within the side frame 5 to support the spring receiver 21 of the track tension adjustment device 15, etc., and the support plate 25 is made of a metal plate having a predetermined thickness. It is formed into a substantially pentagonal shape to correspond to the inner surface shape of the side frame 5, and a nut 2 is installed in the center of the pentagonal shape.
An insertion hole 25A for inserting the rod 18 and the rod 18 is provided. The support plate 25 is fixed around its entire circumference to the inside of the side frame 5 by fillet welding.

The lower running body 1 of a hydraulic excavator according to the prior art has the above-mentioned configuration, and the crawler belt tension adjustment device 15 has a base end of a cover 23 welded to a support plate 25 within the side frame 5. A spring receiver 21, a rod 18, a cylinder 16, a spring 22, etc. are housed inside, and the base end of the spring 22 contacts the support plate 25 via the spring receiver 21, and the tip contacts the spring receiver 16A of the cylinder 16. By contacting the rod 18, the rod 18 is always urged in the direction of extension and presses the idler 9 together with the yoke 8 etc. in the direction of arrow A, and the crawler track 12
The tension can be adjusted. When the undercarriage 1 travels, each crawler track 12 deforms according to the shape of the ground, and when the tension of the track 12 increases, the idler 9 is pressed by the track 12 and moves in the direction of arrow B, and the idler bearing 10 receives the load from the track frame 3 while sliding surface 1
0B slides in the front-rear direction on the upper guide plates 7A, 7A and the lower guide plates 7B, 7B to reduce the rod 18 of the track tension adjustment device 15 via the yoke 8, thereby tightening the drive wheel 11 and idler 9. The tension of each crawler belt 12 is adjusted by changing the distance between them.

[0015]

By the way, in the above-mentioned prior art, each idler bearing 10 fixed to the tip side of the yoke 8 is slid within each guide portion 7 of the idler bracket 6, and the yoke 8, idler 9, etc. Since the structure is such that each idler bearing 10 is supported by the idler bracket 6,
begins to slide within each guide portion 7 of the idler bracket 6 while receiving a load, and the sliding surface 10B of each idler bearing 10 is severely worn, and a gap is created between each idler bearing 10 and each guide portion 7, and the idler 9 This causes vertical wobbling.

Therefore, in the prior art, the idler bearing 1
If the sliding surface 10B of 0 wears out prematurely and rattles occur, the yoke 8 will vibrate together with the idler 9 within the idler bracket 6 when the hydraulic excavator is running, causing the hydraulic excavator to meander or cause the crawler track 12 to collide with the side frame 5. There is a problem in that the upper rollers 13, lower rollers 14, etc. provided on the side frame 5 are damaged due to contact with the rollers.

Furthermore, in order to solve the above problem, measures have been taken such as increasing the length of the idler bearing 10 to form a larger sliding surface 10B, suppressing wear caused by long-term use, and reducing rattling. However, in this case, since the idler bearing 10 is made large, there is a problem in that manufacturing costs increase in terms of materials and processing.

The present invention has been developed in view of the problems of the prior art described above.The present invention can prevent idler bearings from being worn out early even during long-term use, and can solve problems such as idler rattling and meandering. The object of the present invention is to provide an undercarriage for a tracked vehicle that can eliminate the problems.

[0019]

[Means for Solving the Problems] A feature of the configuration adopted by the present invention in order to solve the above-mentioned problems is that the yoke is in sliding contact with each guide portion of each idler bracket, so that each yoke is in sliding contact with each guide portion of each idler bracket. The reason is that a guide protrusion is provided to prevent wobbling.

[0020]

[Function] With the above configuration, the yoke can be brought into sliding contact with each guide part via the guide protrusion, and for example, the load can be shared between the sliding surface of the idler bearing and the guide protrusion, and
Abrasion of sliding surfaces can be suppressed.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 4. In the embodiment, the same components as those in the prior art described above are denoted by the same reference numerals, and the explanation thereof will be omitted.

In the figure, reference numeral 31 indicates a yoke according to the present embodiment, and the yoke 31 has a pair of arm portions 32, 3 branching left and right and extending in parallel, almost the same as the yoke 8 described in the prior art.
2, fastening parts 33, 33 provided at the tip of each arm part 32 and having two bolt holes 33A, 33A, and each arm part 3.
It is composed of a connecting part 34 that connects 2 and 32 together on the proximal end side, and a rod connecting part 35 to which the rod 19 of the crawler belt tension adjustment device 15 is fixed, and has an approximately U-shape as a whole. Here, as shown in FIG. 4, each arm portion 32 of the yoke 31 includes an inner arm portion 32A and a reinforcing plate portion 32 that face each other in the left and right direction.
The outer arm part 32C is integrally formed with the inner arm part 32A via the inner arm part 32A and has a tapered outer arm part 32C, as shown in FIG. 2, and has an H-shaped cross section.

36, 36, . . . are each arm portion 32 of the yoke 31.
2 shows a pitching prevention projection 36 as a guide projection integrally formed on the base end side, and each of the pitching prevention projections 36 extends from the reinforcing plate portion 32B and the outer arm portion 32C on the base end side of each arm portion 32. It protrudes in the vertical direction and is formed into a flat plate with a predetermined thickness as shown in FIG. Further, the outer surface of each pitching prevention protrusion 36 is flush with the outer surface of the outer arm portion 32C,
The upper and lower surfaces are arranged at positions that substantially correspond to the upper and lower surfaces of the inner arm portion 32A. Each of the pitching prevention protrusions 36 is slidably inserted between each of the guide plates 7A and 7B of the idler bracket 6, and the yoke 31 is inserted between each of the guide plates 7A and 7B.
Together with the idler bearing 10, this prevents the shaft from shaking in the vertical direction.

Reference numerals 37, 37, . . . indicate anti-swing protrusions as guide protrusions integrally formed on the proximal end side of each arm 32 together with each anti-swing protrusion 36, and each anti-swing protrusion 37 is integrally formed on the proximal end side of each arm 32. 32 protrudes vertically from the inner arm portion 32A, extends in the front-rear direction with a predetermined thickness, and is formed into a flat plate shape, as shown in FIGS. 1 and 2. Each of the anti-lateral vibration protrusions 37 is in sliding contact with the inner end surface of each guide plate 7A, 7B, and prevents the yoke 31 from rattling in the left-right direction within the idler bracket 6.

The lower traveling body of the hydraulic excavator according to this embodiment has the above-described structure, and its basic operation is not particularly different from that of the prior art.

However, in this embodiment, each arm portion 3 of the yoke 31 is inserted into each guide portion 7 of the idler bracket 6.
2, each anti-swing protrusion 36 and anti-yaw protrusion 37 are integrally formed, and each anti-yaw protrusion 37
is in sliding contact with the inner end surface of the guide plates 7A, 7B of each guide portion 7, and each pitching prevention protrusion 36 is slidably inserted between each guide plate 7A, 7B. When each arm portion 32 of the yoke 31 is assembled between each guide portion 7 of the idler bracket 6 together with each idler bearing 10 fastened to the distal end side of the arm portion 32, each pitching prevention protrusion 36
and each rolling prevention protrusion 37 can restrict rattling in the vertical and horizontal directions of the yoke 31, and each pitching prevention projection 36 can share the load applied to the idler bearing 10, and each sliding surface of the idler bearing 10 can be It is possible to reliably prevent premature wear of 10B.

Furthermore, as described in the prior art, it is possible to suppress the wear of the idler bearing 10 and prevent the idler 9 from rattling even without making the sliding surface 10B of the idler bearing 10 large. For example, it becomes possible to downsize the idler bearing 10, and it is possible to reduce costs.

Therefore, according to this embodiment, it is possible to reduce the wear of the sliding surface 10B of the idler bearing 10 over a long period of time when the undercarriage 1 is running, and it is also possible to prevent the idler 9 from wobbling and meandering during running. or upper roller 13 or lower roller 1.
This has various effects such as preventing damage to the hydraulic excavator 4 and improving running performance and safety of the hydraulic excavator.

In the above embodiment, each arm 32 of the yoke 31 is provided with each pitching prevention projection 36 and each rolling prevention projection 37 as a guide projection, but the present invention is not limited to this. Instead, for example, each anti-rolling protrusion 37 may be omitted and only the anti-pitch protrusion 36 may be formed as a guide protrusion.

Furthermore, in the above embodiments, a hydraulic excavator was used as an example of a tracked vehicle, but the present invention is not limited to this, and may be used in other tracked vehicles such as a hydraulic crane. can also exhibit similar effects.

[0031]

[Effects of the Invention] As detailed above, according to the present invention, each yoke is provided with a guide protrusion that slides into each guide portion of each idler bracket and prevents each yoke from wobbling with respect to each guide portion. Because of this, the load acting on the sliding surface of the idler bearing can be shared by the guide protrusion, which can effectively prevent the sliding surface of the idler bearing from wearing out prematurely, and prevent rattling of the idler and tracked type. This eliminates problems such as the vehicle meandering or damage to parts caused by contact between the track and the side frame, and improves reliability and safety.

[Brief explanation of drawings]

FIG. 1 is a front view showing a yoke according to an embodiment of the present invention.

FIG. 2 is a bottom view of the yoke shown in FIG. 1.

FIG. 3 is a left side view of the yoke shown in FIG. 1.

FIG. 4 is a longitudinal cross-sectional view showing the yoke of FIG. 1 attached to each guide portion of the idler bracket.

FIG. 5 is an overall view showing a conventional hydraulic excavator.

6 is a longitudinal sectional view showing a side frame, an idler bracket, etc. of the hydraulic excavator shown in FIG. 5. FIG.

FIG. 7 is a sectional view taken along arrow VII-VII in FIG. 6;

FIG. 8 is a front view showing a yoke according to the prior art.

9 is a bottom view of the yoke shown in FIG. 8. FIG.

10 is a left side view of the yoke shown in FIG. 8. FIG.

11 is an enlarged sectional view in the direction of arrow XI-XI in FIG. 7. FIG.

12 is an enlarged cross-sectional view in the direction of arrows XII-XII in FIG. 7, showing a state in which the idler and the like are removed from the yoke.

[Explanation of symbols]

1 Lower running body 2 Upper rotating body 3 Track frame 5 Side frame 6 Idler bracket 7 Guide part 7A Upper guide plate 7B Lower guide plate 9 Idler 11 Drive wheel 12 Crawler track 15 Crawler tension adjustment device 31 York 32 Arm part 36 Pitch prevention protrusion 37 Anti-lateral vibration protrusion

Claims (1)

[Claims] 1. A track frame including a pair of side frames on both left and right sides, and a pair of guide portions provided at one end of each side frame of the track frame, facing each other in the left-right direction and extending in the front-rear direction. left and right idler brackets each having a left and right idler bracket, left and right yokes that are disposed between each guide portion of each of the idler brackets and slide in the front and back direction along each of the guide portions, and each of the side frames. The left side is located at one end and is rotatably supported by each yoke.
Wrapped between the right idler, the left and right drive wheels provided at the other end of each side frame and rotationally driven by a traveling actuator, and each drive wheel and each idler. left and right crawler tracks, and left and right track tension adjustment devices that are provided on each side frame to adjust the tension of each track, and that slide each yoke along each guide portion of each idler bracket. In the undercarriage of a tracked vehicle, each yoke is provided with a guide protrusion that slides into contact with each guide portion of each idler bracket and prevents each yoke from shaking with respect to each guide portion. An undercarriage body of a tracked vehicle characterized by the following.