Mounting process of medium-speed high-strength diesel engine cylinder cover water-cooled exhaust valve seat

Abstract

The invention discloses a mounting process of a medium-speed high-strength diesel engine cylinder cover water-cooled exhaust valve seat. The process comprises the following steps of: (1) processing a mounting part matched with the exhaust valve seat and an exhaust valve seat hole of a cylinder cover according to the mounting interference requirement of the cylinder cover exhaust valve seat, soaking the exhaust valve seat into liquid nitrogen for freezing for 32-38 seconds and then taking out; (2) quickly loading an O-shaped rubber ring in a sealing slot on the exhaust valve seat taken out in the step (1); (3) immediately arranging the exhaust valve seat obtained in the step (2) in an exhaust valve seat hole of the cylinder cover; (4) and after the temperature of the exhaust valve seat rises to environmental temperature, finishing assembling. In the invention, the freezing temperature of the exhaust valve seat is controlled through accurately controlling the freezing time of the exhaust valve seat, so that the freezing temperature of the exhaust valve seat can be more accurately controlled, the exhaust valve seat can be guaranteed to be normally arranged in the exhaust valve seat hole of the cylinder cover, the O-shaped rubber sealing ring cannot be subjected to cold-brittle fracture so as to avoid cooling water from being leaked, and the running reliability of a medium-speed high-strength diesel engine is improved.

Description

technical field [0001] The invention relates to the technical field of diesel engines, in particular to a method for installing a water-cooled exhaust valve seat on a cylinder head of a medium-speed high-strength diesel engine. Background technique [0002] In the prior art, the exhaust valve seat of the non-highly strengthened diesel engine cylinder head has no water cooling, so there is no need to install an O-shaped rubber sealing ring to prevent the leakage of cooling water, because the exhaust valve seat and the cylinder head need to be installed with interference, The exhaust valve seat needs to be frozen and shrunk and then put into the exhaust valve seat hole of the cylinder head. When installing, only put the exhaust valve seat in liquid nitrogen and freeze it for about 2 to 4 minutes, and its temperature will drop to about - Install it in the exhaust valve seat hole of the cylinder head after 180°C, and complete the installation when the temperature rises to ambien...

AI Technical Summary

Problems solved by technology

During the installation process, the exhaust valve seat is also installed in the exhaust valve seat hole of the cylinder head by freezing and shrinking, and the temperature measuring instrument is used to detect the temperature of the exhaust valve seat in freezing to control the freezing temperature, but due to There are many factors that affect the installation process of the exhaust valve seat, such as the ambient temperature, the freezing time of the exhaust valve seat, the temperature after the exhaust valve seat is frozen, etc., making it difficult to control the installation temperature parameters of the exhaust valve seat to a certain value through temperature measuring instruments. On the precise temperature, moreover, the price of this temperature measuring instrument is also more expensive, causes the increase of manufacturing cost, and the prior art also has the following deficiencies simultaneously:

[0004] (1). For high-intensity diesel engines, the freezing temperature of the exhaust valve seat is difficult to control accurately, which often leads to the freezing temperature not being low enough, and the shrinkage size does not meet the requirements, so normal assembly cannot be realized;

[0005] (2). The freezing temperature of the exhaust valve seat. If the above-mentioned installation process of the exhaust valve seat of the non-highly strengthened diesel engine cylinder head is adopted, the freezing temperature will be too low, although the exhaust valve seat can be placed in the exhaust valve seat of the cylinder head. However, during the installation process, the O-shaped rubber sealing ring is easily distorted by shear force, squeezed and brittle, or when the O-shaped rubber sealing ring is installed in the sealing groove of the exhaust valve seat, it will freeze quickly. Embrittlement and loss of elasticity will cause the function of preventing water leakage to fail, resulting in exhaust valve seat cooling failure, which will seriously affect the normal operation of the exhaust valve, thereby reducing the reliability of diesel engine operation

[0006] Therefore, in order to meet the effectiveness of the installation of the exhaust valve seat, the freezing temperature of the exhaust valve seat must be strictly controlled, but the above-mentioned purpose cannot be achieved by using the existing temperature measurement method