High-power bulldozer crawler tension device sealing performance improvements - 2020
07 -
07 guang-yao zhang Zhang Liangliu yue qi (
Shantui Construction Machinery Co. , Ltd. Research institute)
1 a type high-power bulldozer walking trolley crawler tension device grease leakage fault.
To this end, we according to its structure analysis oil leak reason, and the sealing performance is improved.
1.
Crawler bulldozers walking trolley tensioning device structure is mainly composed of guide wheel 1, 2, crawler tension device platform frame 3, track roller was 4, wheel (5, 6, driving wheel of 7, as shown in figure 1.
This type bulldozer tensioning device is mainly composed of the tension spring tube 1, tension spring 2, 3, 4 push fork, tensioning cylinder car tensioning cylinder 5 and so on, as shown in figure 2.
Push fork four front installation guide wheel, back end cap on the tension spring 2, tension spring 2 through the flange on the tensioning cylinder 3, tensioning cylinder 3 at the other end is fixed on the frame, 4.
The impact of the guide wheel bear by pushing the fork, tension spring 2, 4 tensioning cylinder is passed to the frame, 3 contractions in tension spring 2 absorb and buffer the impact of the guide wheel to bear.
Crawler need tension, through the nozzle to inject grease tensioning cylinder 3.
Grease into the tensioning cylinder 3 on the right side of rodless cavity, make tensioning cylinder 3 rodless cavity form high pressure, and make the tensioning cylinder piston rod out 3, by tensioning the spring push push fork 2 and 4, the mobile guide wheel to left, the crawler tension.
Bulldozers driving process, guide wheel under the impact of the constantly changing, tension spring scale, 2 the length is also constantly changing.
Tension spring 2 installed on the tension spring tube 1, tension spring tube 1 set inside the car tensioning cylinder 5 tension spring tube 1 note with grease.
Car tensioning cylinder 5 head is equipped with dust ring, ring, sealing ring, such as seals, dust ring, sealing ring are overloaded Yx type reciprocating axial sealing ring, so as to ensure the tension spring tube 1 lumen grease does not leak.
Car tensioning cylinder head seal components as shown in figure 3.
2.
Failure reason analysis guide wheel and release under impact, the tension spring is telescopic repeatedly, as tension spring tube with frequent friction between car tensioning cylinder head, causing wear dustproof ring, ring, sealing ring.
The original sealing ring with nitrile butadiene rubber, the material is easy to wear and leakage.
We check the bulldozer tensioning device when the spill, found that the oil spill area is located in the lip of seal ring, distortions and inner lip.
Sealing ring seal failure are caused by the analysis, the following four reasons: one is the sealing ring with tension spring tube outer wall under the condition of overloading friction quickly, because of the higher coefficient of friction, the friction is bigger, lead to the serious wear and tear,
2 it is because of the tension spring tube and the relative motion between car tensioning cylinder speed too fast, caused the sealing ring contact surface distortion;
Three is the insufficient rubber elastic compensation itself, make the seal failure;
Four is sealing ring material wear-resisting performance is poorer, failure due to wear and tear easily.
Yx type seal failure, lip area cannot keep effective contact with the walls of the cavity, causing grease from the contact surface.
3.
Improved method (
1)
Design of new type sealing ring to achieve good sealing effect, we designed a new type of sealing ring, as shown in figure 4.
The new sealing ring composed of Yx type seal and o-ring, Yx type sealing ring and the inside and outside the cavity using lip line contact, to reduce the friction sealing parts area, to reduce the friction resistance.
Yx type sealing ring in his lips is shorter and thicker, increase the stiffness of the inner lip place, effectively avoid lip distortion.
Yx type sealing ring groove in the middle add o-ring, improve the whole rigidity and elasticity of Yx type sealing ring, and can provide the proper pressure.
Yx type sealing ring baffle ring and axial fixation, external cavity wall pressure grease, hit the Yx type sealing ring clamp force increased.
O-ring can timely receive the clamping force and feedback to the inner and outer lip, to maintain the Yx type sealing ring internal, external cavity wall pressure force.
Bulldozers to use after a period of time, Yx type sealing ring may gradually wear and o-ring can compensate for wear, in order to make Yx type sealing ring has enough flexibility, prolong the service life of Yx type sealing ring.
In order to keep the tension spring tensioning cylinder sealing tube and vehicle, we chose to use polyurethane rubber to make the Yx type sealing ring.
The material has good mechanical strength, hardness, and ability of high temperature, also has certain compressibility and resilience, the lip has good wear resistance, the material in the axial reciprocating a lower friction coefficient at high speed.
Its internal o-ring has higher hardness and elasticity of the silicone rubber.
According to actual use bulldozers climate and the temperature of the location, the o-rings also can choose high temperature resistance of fluorine rubber or low temperature resistant chlorohydrin rubber.
（
2)
Improved processing technology we are in a tension spring tensioning cylinder tube and car processing technology, processes, size deviation and assembly accuracy control, make reasonable deformation of seal ring, sealing ring and its contact more closely, make the high-power bulldozer tensioning device sealing performance is better, in order to achieve the expected effect of sealing.
Source: 'engineering machinery and maintenance' 08, 2017
