Engineering machinery crawler walking device "track-cutting" phenomenon

"Rail gnawing" is a typical fault phenomenon of crawler construction machinery, which shows the service life of guide rail, supporting wheel, driving wheel, supporting wheel and crawler when the whole machine is walking. There are side gaps between the track and the four wheels, in which the clearance between the guide wheel and the guide wheel is the smallest, and the backlash of the supporting wheel is the biggest. Under normal circumstances, the track and the "four wheel" will occur between normal friction, but will not occur "gnaw rail"". The fundamental reason for "gnawing rail" is that the track can not be correctly winded; the center surface of the four wheel does not coincide.

1. "Gnawing rail" caused by guide wheel"

Guide wheel is an important part of the walking system, and its installation position has a great influence on the life of the walking system. In normal circumstances, the crawler should be in the middle of the guide wheel winding, in addition to a short side shift in the turning, the track generally does not slip. However, if the steering wheel is skewed, the track will be subjected to a component component acting in an oblique direction, causing it to move axially, resulting in a "gnawing rail" phenomenon. The direction of the guide wheel tilt, caused by eating the guide wheel wheel position is different, if the guide wheel in the horizontal plane is tilted, will produce "track-cutting" in front of the guide wheel; if the vertical plane tilt, usually at the bottom of the guide wheel, "track-cutting". Serious when can cause the front roller off edge; when the two tilt existing at the same time, there will be "eight track-cutting" phenomenon. It can be seen that the installation position of the guide wheel is correct or not, which has a great influence on whether the track is gnawing rail or not.

Influence of guide wheel installation position is the main factor:

(1) the coaxiality between the circle formed by the center of the 8 screw holes at the end of the hole of the spring box and the spring box bore is too bad. After assembly, the longitudinal center line of the guide wheel does not coincide with the longitudinal center line of the frame.

(2) the verticality of spring box front longitudinal center hole hole end surface and the frame line super bad. And the installation verticality of support wheel frame is super bad.

(3) the center line parallelism of the base box spring with spring box hole deviation.

(4) the center line of the half round hole with eccentric pin installed on both ends of the guide axle is not parallel, which leads to the asymmetry of the left and right brackets after assembly, resulting in the tilting of the guide wheel.

(5) the location of each 4 holes left and right bracket is connected with a guide wheel bracket with error.

(6) adjust the clearance between the guide wheel bracket, and wear plate improper.

In addition, if the guide wheel machining defects will lead to "track-cutting", such as the production of axial offset guide wheel intermediate shoulder processing; both sides of the raceway diameter is different, the tension force on both sides of the track, the track is easy to transfer, raceway generatrix and track pin axis is not parallel, so that the shoe with local sideslip.

2. "Gnawing rail" caused by the support wheel"

Roller is the role of the weight of the machine is transferred to the track. In the process of running the machine, it not only tracks along the track of the track, but also holds the track, does not let it slide out; when the machine turns, it also makes the track on the ground lateral sliding. The support wheel is divided into two types, one side and two sides. Taking TY220 crawler bulldozer as an example, there are 12 supporting wheels, of which 4 are bilateral and 8 are unilateral. Unilateral and bilateral supporting wheels together form a raceway track, rolling on the track. When the track bus does not coincide with the center line of the idler gear block and the center line of the guide wheel, it will cause the wheel to gnaw the rail".

The reason why the wheel is gnawing rail is mainly:

(1) supporting wheel fixing bolt loose, causing heavy axial position changes or skew.

(2) the locating groove of the heavy wheel is seriously worn out.

(3) the center line of a set of holes in the fixed support wheel of the frame is not perpendicular to the straight hole formed by the installation hole of the semi axle and the installation hole of the inclined support

(4) intermediate flange processing wheel generates offset.

(5) bus and raceway track pin axis is not parallel to the track of sideslip.

(6) the diameters of the raceways on both sides of the supporting wheel are different.

(7) when the support wheel is machined, the raceway is too small in size, so that the gap between the track and the track is smaller than the clearance between the guide wheel and the track, causing the gnawing rail".

3. "Gnawing rail" caused by driving wheel"

The backlash between the driving wheel and the track is the largest, and the rail will not occur, but if the center line of the block is not coincident with the center line of the guide wheel and the supporting wheel, it will cause the gnawing rail".

The main reason of "gnawing rail" of driving wheel is:

(1) when pressing the supporting wheel, the center line of the supporting teeth block does not press the position or the position of the end face of the inner shell.

(2) the concentricity of the bearing holes on the supporting holes of the frame and the bearing holes on the half axle support is not perpendicular to the longitudinal centerline of the block and the frame.

(3) half shaft bracket or half shaft axial dimension processing error, caused by a driving wheel is installed in place.

(4) due to the use of hair, causing half shaft bending, driving wheel flat deflection.

4, "rail gnawing" caused by deformation of frame"

The frame is a rectangular frame structure by U and L shape formed by connecting. "Four wheel" and are mounted on the buffer device. The destruction of "three position" and the driving wheel deformation of frames, causing "track-cutting".

Frame deformation caused by the main reason why "track-cutting" is:

(1) trolley beam bending. The bending of the trolley beam includes the bending in the horizontal and vertical planes; from the influence of the whole machine, the bending in the non plane has the biggest influence on the rail gnawing, and it also causes the deviation of the whole machine.

(2) crotch deformation in front of pallet rack. One is to separate outward, two is to open crotch skew.

(3) inclined support deformation of frame. This will destroy the mounting position of the frame.

By 5, wear and other reasons "track-cutting"

The frame of poor working conditions and under external force, it is prone to wear. The main causes of "gnawing rail" are:

(1) the wear of the mounting surface and the fitting surface of the frame is larger, and the verticality of the trolley beam and the half axle is destroyed.

(2) Taiwan frame mounting bolt looseness caused by the rail gnawing".

(3) the foreign body is clamped between the guide wheel and the frame, so that the guide wheel can not be adjusted.

In a word, cause "track-cutting" is very complex, not only to pay attention to the problem of processing and assembly process, should be more often in use of walking components are not regular inspection and adjustment, to prevent the "track-cutting". Namely: check gap between the outer cover and the guide wheel trolley beam, not up to the requirements to be adjusted accordingly; adjusting the axial position of the wheel frame is fixed; check whether the bolts fastening; whether there is a foreign body check between the guide wheel and the frame.