(1) Failure of mechanical parts and mechanical failure The loss of working ability of the machine is called failure, and the loss of the specified working capacity of the machine parts is called failure. Mechanical failures and failure parts are inseparable. Since the normal wear part or parts of physical and chemical changes caused by deformation, fracture, pitting and the like failure due to failure of components, such failure also called natural fault. (II) Elimination (repair) method of mechanical failure The elimination of man-made accidental faults is mainly achieved by improving the quality of use, management and maintenance personnel and strengthening the sense of responsibility. Natural failures can only be achieved by adjustment and repair methods. There are usually the following methods: Twinkle System Technology Co Ltd , https://www.pickingbylight.com
1. Wear and wear of parts is the most important and common form of part failure.
2, the deformation of the machine in the working process, due to the force of the force, the phenomenon of the size and shape of the part is called deformation. The deformation of the metal includes elastic deformation and plastic deformation.
3. The fractured part of the part first undergoes elastic deformation under the action of external force. When the stress caused by the load exceeds the elastic limit and continues to increase, the material may be plastically deformed, and finally the fracture occurs when the stress exceeds the strength limit.
4. The point flaking on the surface of the damaged parts under the cyclic contact stress is called fatigue pitting; the chemical and electrochemical action of the parts on the surface causes the damage of the surface metal to be called corrosion; the parts change in temperature and medium. The lower surface produces needle-like holes and is constantly expanding called acupoints. Fatigue pitting, corrosion and hole erosion are collectively referred to as erosion.
1. Repair methods for the main restoration of the nature of cooperation
(1) The adjustment method generally uses the adjustment of the bolt tightness or the adjustment of the thickness of the gasket to restore the original fitting relationship of the fitting. The fitting is not processed (or only scraped), but only the gasket is added or adjusted. The thickness of the spacer is restored to the original fit clearance.
(2) Repair dimension method During the repair, the more expensive parts of the fittings are machined to restore their geometry, and at the same time a new size is obtained, and then another worn part of the fitting is discarded and replaced with a new one. The matched parts of the machined parts restore the matching clearance of the fitting to the initial clearance, such as repairing the shaft and changing the bearing bush, and repairing the cylinder to change the piston. This repair method should consider the possibility of machining the part structure and the mechanical strength allowed after the repair of the part. Under this premise, the number of repairs should be increased as much as possible; on the other hand, the repair size should be standardized in order to facilitate the supply of spare parts.
(3) Supplementary part method (additional part method) This method applies to each part of the fitting, and gives a reasonable diameter reduction or reaming to one of the parts, and then adds a similar material or quality to it. The higher bushing is press-fitted or threaded into the original part by interference or machined to the mating size to meet the required fit.
2. Repair method for restoring the nature of the fit and restoring the shape and size of the part
(1) Welding repair method Metal welding is to firmly combine the separated metal weldments into a whole by diffusion and connection between atoms. According to different welding equipment, there are gas welding and electric welding, etc. Many fracture and wear parts are mostly used. Repaired by the repair welding and surfacing methods, some parts are subjected to grinding and grinding after welding to restore the original geometry and size.