Common oil leakage causes and improvement measures

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Common causes of oil leakage in printing machines and their improvement measures

oil leakage in the operation of printing machines is divided into oil leakage at the shaft end of the drum, oil leakage at the junction of the shaft connection and the protective cover, oil leakage at the junction of the protective cover and the wallboard, oil leakage at the end of the paper delivery shaft, and oil leakage at the roll shifting

(1) when the air is removed, the pressure in its inner cavity decreases, and the oil in the oil return hole and oil return tank will not flow back to the oil tank, but will flow out with the rapid movement of the shaft, resulting in oil leakage. 5. Software and hardware of tensile testing machine:

(2) the shaft moves and rotates during operation, and its movement is relatively complex. That is to say, the 0-shaped ring not only bears the axial friction, but also produces a twisting force due to the friction on the surface of the rotating shaft. How to reduce these two forces to ensure the normal sealing of the 0-ring and prolong the service life of the 0-ring is something the designer must consider. In practice, the size of the 0-ring is 41mm 3.5mm, the inner diameter is 41mm-2 3.5mm=34mm, the size of the groove in the sleeve is 4,41h8, and the size of the shaft is 4) 35f7. That is to say, the inner diameter of the 0-shaped seal ring should be increased by 1mm during assembly. In work, the 0-shaped ring is in tension, and the holding force with the surface of the shaft is also large. Therefore, there is a lot of friction between the shaft and the 0-ring in the axial and circumferential directions, resulting in complex deformation of the 0-ring. Secondly, the friction is very large, and the 0-ring wears quickly (the wear of the 0-ring removed from the machine can illustrate this). According to the relevant information on the research of refractory B1 thermal insulation materials, the 0-ring is used as a rotary seal, and friction occurs between the 0-ring and the shaft. When the 0-ring is in tension, friction and wear are very strong, and heat is generated. According to the Kraft Joule effect, rubber expands after heating; At the same time, in the tensile state, it shrinks violently, leading to vicious friction, which makes the rubber 0-ring age rapidly and fail: therefore, the machine will leak oil after working for a period of time

(3) the coaxiality of the annular groove 4,41h8 in the sleeve and the inner hole 4) 35f7 is greatly out of tolerance due to manufacturing and requirements, resulting in the deviation of the 0-ring from the axis in the detection of the new national standard, loss of sealing effect and oil leakage. (4) The manufacturing accuracy of 0-ring is poor, and the cleaning of its cutting surface is unqualified, resulting in poor sealing effect. Thirdly, the material of 0-ring is poor and the wear is fast. The machine leaks oil after working for a period of time. According to the above leakage reasons, the following measures can be taken after 1 month of trial operation: (1) reasonable design. The 0-ring should have an appropriate amount of compression (less than 5%), that is, inward compression. For this reason, there are two schemes: ① the size of the journal is equal to or less than 3% of the inner diameter of the 0-ring, and the size of the groove of the sleeve is less than the size of the outer ring of the 0-ring, so that the 0-ring has a compression of 3% - 5%; ② Based on the existing structure, the specification of 0-ring is changed to 42mm 3.5mm. From the test results, it can fully meet the sealing requirements, bring some convenience to the assembly, reduce the factors of damage, and cancel the rear oil return hole. (2) Improve the machining accuracy of parts, especially the coaxiality between the sealing groove and the inner hole is required to be 0.05mm; And reduce the surface roughness of the shaft. (3) Ensure the material requirements of the 0-ring and the quality requirements of the cutting surface, and the cutting surface shall be flat and smooth

(4) it is also caused by non-standard operators. If the operation is not careful when installing the sealing ring; Secondly, when the lip of the seal ring is smaller than the shaft diameter, it is difficult to assemble, so we use a screwdriver to skim and knock with a hammer to skim and knock the lip of the seal ring, which destroys the seal appointment; Third, the sharp edges and burrs at the population of the shaft and hole seal ring are not completely removed, and the lip of the seal ring is scratched during assembly, damaging the sealing effect; Fourth, put the shaft on the sealing ring during assembly, causing the lip of the sealing ring to deform and affect the seal

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