Harm：

(1) the mechanical deformation, thermal expansion coefficient of hydraulic components in different moving parts due to clearance is smaller and stuck, causing failure, affect the transmission precision of the hydraulic system, resulting in poor quality components.

(2) the viscosity of the oil is reduced, the leakage is increased, and the volume efficiency of the pump and the efficiency of the whole system are significantly reduced. As the viscosity of the oil decreases, the oil film of the sliding parts such as the slide valve is thinned and cut off, and the friction resistance increases, leading to the increase of wear.

(3) make the rubber seal deformation, accelerate the Liao failure, reduce the sealing performance and service life, resulting in leakage.

(4) accelerate the oxidation of oil, and release asphalt material, reduce the service life of hydraulic oil. The precipitates clog the damping orifice and the slit valve port. Lead to the pressure valve stuck and can not move, metal pipe elongation and bending, and even rupture.

(5) the separation pressure of the oil is reduced, the dissolved air in the oil escapes, and the cavitation is generated, resulting in the decrease of the working performance of the hydraulic system.

Prevention measures:

(1) according to different load requirements, the pressure of the relief valve is often checked and adjusted to make it right.

(2) reasonable choice of hydraulic oil, especially oil viscosity, under the conditions permit, as far as possible to use a lower viscosity to reduce viscosity loss of friction.

(3) improve the lubrication condition of the moving parts, reduce the friction loss, reduce the working load and reduce the fever.

(4) improve the assembly quality and self precision of hydraulic components and hydraulic system, strictly control the fitting clearance and improve the lubrication conditions of the fitting parts. The friction coefficient of small sealing material and improved sealing structure, as far as possible to reduce the starting force of hydraulic cylinder, in order to reduce the mechanical friction loss generated by heat.

(5) add cooling device when necessary.