What to do with journal wear, what are the causes of crankshaft journal wear?

The problem of journal wear occurs from time to time in the management and maintenance of equipment in industrial enterprises. However, with the continuous improvement of the degree of automation and continuity of enterprise equipment, how to quickly and effectively solve problems and reduce maintenance costs, and ensure the safe and continuous production of enterprises is an important embodiment of the management ability of equipment managers in the new era.

1. Traditional methods of shaft wear repair.

1. Play "pockmarks".

Advantages: low cost; Fast repair.

Disadvantages: low contact surface; Limitations; Short service life; The hidden danger is big.

2. Machining after repair welding.

Advantage: Low maintenance costs.

Disadvantages: Cannot be repaired repeatedly; Shafts that are easy to break cause major accidents; The hidden danger is large and the comprehensive cost is high.

3. Inserting. Advantages: low cost;

Disadvantages: low contact surface; Short service life; The equipment has a large runout.

4. Brush plating and spraying.

Advantages: low thermal stress, relatively little damage to the material.

Disadvantages: There is a limit on the size of wear; Unable to be repaired on site; easy delamination; High cost.

5. Plugging copper skin.

Advantages: low cost; Fast repair.

Disadvantages: low contact surface; Short service life; The hidden danger is big.

2. The most cutting-edge shaft wear repair technology imported from the United States.

Application fields of high thixotropic nano-metal polymer materials: protection of pumps, water turbines, tanks, condensers, etc.; Wear repair of various bearing positions, bearing chambers (seats), keyways, threads, etc.; Casting defects, cracks, transformer oil leakage.

The high-thixotropic nano-metal-based polymer composite material imported from the United States is a high-performance epoxy two-component composite material reinforced by carbon nanotubes and nano-inorganic materials. The biggest advantage of this material is that the special nano-inorganic material is bonded with the oxygen of the epoxy ring molecule to improve the intermolecular bonding force, thereby greatly improving the comprehensive properties of the material, and can be well adhered to various metals, concrete, glass, plastics, rubber and other materials. It has good resistance to high temperature and chemical corrosion.

At the same time, good machinability and wear resistance can serve the wear regeneration of metal parts.

Due to the wear and tear of the size of the sintering trolley, the sintering machine of the iron and steel enterprise stops due to the difference in running position, and the enterprise adopts the reversing behavior to resume the operation of the equipment, which eventually causes the shaft and the expansion sleeve to wear out and stop.

132 Sintering machine, gear drive shaft wear, journal: 380mm, matching mode: use 3 sets of Z2 expansion sleeve, shaft diameter wear width: 400mm, due to the relative movement of the expansion sleeve and the shaft caused by wear, wear depth: 1-6mm.

Journal wear on-site repair**:

Traditional technologies such as repair welding machine processing, brush plating, thermal spraying, laser cladding, and a new maintenance mode that has emerged in recent years uses polymer composite materials for on-site repair, such as 2211F metal repair materials, which is characterized by no need to disassemble the equipment, as long as the working surface is exposed, and the repair is fast, saving valuable production time for enterprises.

It is recommended to use 2211F metal repair materials for on-site repair, which has solved many transmission parts wear problems, such as the wear of bearing positions, bearing chambers and other transmission parts of roller presses, motors, fans, crushers, pumps, reducers and other equipment, and the use effect and acceptance effect in major enterprises are quite good.

Looking at the picture, it is recommended to use 2211F metal repair material to repair.

The radial clearance between the crankshaft journal and the bearing is small, which allows the crankshaft to rotate freely without openness and radial runout. If the radial clearance between the journal and the bearing changes, it will often cause early wear and damage of the crankshaft journal and the shaft, which will increase the engine working vibration, increase the noise, increase the fuel consumption and increase the accident. Damage to the crankshaft journal and bearing can take the form of scratches, wear, fatigue peeling, corrosion, and burning.

Summary. The reasons for the wear of the crankshaft journal are as follows:1

Poor lubrication: The crankshaft journal needs to be adequately lubricated when rotating at high speeds, and if the lubrication is poor, the friction will increase, resulting in journal wear. 2.

Poor oil quality: Using a poor quality oil or using it for too long can cause additives and lubricants in the oil to break down and lose their lubricating properties, which can lead to journal wear. 3.

Excessive loads: Crankshaft journals are subjected to enormous loads when rotating at high speeds, which can lead to journal wear if they are exceeded. 4.

Bad usage habits: Long-term high-speed driving, frequent rapid acceleration, sudden braking and other bad usage habits will lead to crankshaft journal wear. 5.

Bearing failure: Bearing failure can lead to journal wear as the bearing loses support and protection for the journal. 6.

Poor material quality: Poor material quality and insufficient hardness of the crankshaft journal can also lead to journal wear.

Hello, there are several reasons for crankshaft journal wear, which leads to this situation.

The cause of crankshaft shaft wear.

The reasons for the wear of the crankshaft sideboard journal are as follows:1Poor lubrication:

The crankshaft journal needs to be adequately lubricated when rotating at high speeds, and if the lubrication is poor, friction will increase, leading to journal wear. 2.Poor oil quality:

Using a poor-quality oil or an oil that has been used for too long can cause additives and lubricants in the oil to break down and lose their lubricating properties, which can lead to journal wear. 3.Overload:

The crankshaft journal is subjected to a huge load when rotating at high speeds, which can lead to journal wear if it exceeds its tolerance range. 4.Bad usage habits:

Long-term high-speed driving, frequent rapid acceleration, sudden braking and other bad habits will lead to crankshaft journal wear. 5.Bearing failure:

Bearing failure can lead to journal wear because the bearing loses support and protection for the journal. 6.Poor quality of materials:

Poor material quality and insufficient hard finish of the crankshaft journal can also lead to journal wear.

You send it out. **Can't open.

At the end of compression, the pressure of the gas in the cylinder mainly depends on which two.

The gas pressure in the cylinder depends mainly on two factors: the volume of the combustion chamber and the position of the pistons. Empty belt When the piston moves upwards, the volume of the combustion chamber decreases and the gas is compressed, which increases the pressure of the gas.

As the piston dissolves and moves downward, the volume of the combustion chamber increases and the gas is stretched, which reduces the pressure of the gas. Therefore, the gas pressure in the cylinder depends on the volume of the combustion chamber and the position of the piston.

Excessive wear and tear is mainly caused by improper use of the car and untimely maintenance. For example, when the wear of the mating gap between the journal and the bearing increases, and the bearing cannot be repaired and replaced in time, the oil supply pressure decreases, which increases the shock load and leads to accelerated wear. Failure to clean and replace the engine oil on time will also cause abnormal wear and tear on the shaft journal.

It should be the poor oil quality, poor lubrication, low oil pressure, crankshaft bearing damage, and repeated parking of the vehicle are all reasons.

Torsional fatigue and flexural fatigue.

In the end, there must be a problem with the oil.

Journal wear is easy to cause equipment with injury operation, resulting in low production efficiency, accelerated equipment aging, affecting product quality and a series of hazards, serious will cause equipment forced shutdown or the entire production line of the blind machine, resulting in the loss of production time, delay the delivery date, dust sail and even hail caused serious safety production accidents, individual industry equipment due to journal wear, production forced shutdown and maintenance and even the entire production line scrapped accidents, enterprises were forced to go bankrupt overnight.

<> the circular runout of the crankshaft flange disc end facing the axis of the main journal should not be greater; The radial circular runout of the outer circle should not be greater than that, and when it exceeds the technical specifications, it can be eliminated when grinding the crankshaft with the timing gear journal and the rear oil journal as the benchmark when grinding the crankshaft.

Repair of bolt holes in crankshaft flange discs.

If the bolt hole on the rear flange disc of the crankshaft exceeds the roundness error after wear, the hole can be reamed and repaired, and the flywheel can be fixed with an enlarged fixing bolt instead.

When the bearing hole of the first axle front bearing of the transmission is installed on the crankshaft rear flange disc, and the radial runout of the main journal axis line is not greater, it can be repaired by the inlay method.

In addition, if the timing gear keyway is worn or defected, it should be welded and repaired, and then the keyway should be milled to the original size.

The wear of the crankshaft journal is often uneven, often worn into an oval and tapered shape.

Abrasions and burns may also occur on the journal surface. Abrasions are caused by hard debris such as metal shavings remaining in the engine due to unclean lubricating oil. Burns on the surface of the journal are caused by insufficient oil pressure or too little clearance between the journal and the bearing.

At this time, the journal and the bearing are violently rubbed, and the temperature rises sharply, causing the surface of the journal to burn. In severe cases, the bearing metal melts and adheres to the journal, causing the crankshaft to jam or even break.

Causes of journal wear: In industrial production, machinery and equipment are used more, in use, due to a variety of reasons, such as: improper coordination between the shaft and the pulley or coupling, long-term overload operation, the journal of the sliding bearing due to poor lubrication, the lubricating oil with iron filings, sand particles and other impurities or due to the manufacturing quality is not high, the heat treatment can not meet the requirements, or the shaft is hit by external force and other causes the journal to wear, and even cause the journal to break in serious cases.

During the use of the shaft, the size is out of tolerance due to gradual wear, or serious thermomechanical fatigue cracks are produced locally, which affects the quality. There are many ways to repair shafts, and the most commonly used traditional methods are electric welding, machining, which is cheap in equipment materials, simple repair process, easy to learn and use. With the continuous emergence of modern repair technology, users can choose nesting, brush plating, thermal spraying, EDM, patch, polymer materials, etc., according to the actual production needs.

1. Traditional Methods:

Domestic for shaft wear is generally used repair welding, inlay bushing, pitting, etc., if the downtime is short and there are spare parts, the general replacement of new shafts, some maintenance technology higher enterprises will use brush plating, laser welding, micro arc welding and even cold welding, etc., these maintenance technology needs to purchase expensive equipment and high salaries to hire skilled workers, some small and medium-sized enterprises in China generally through higher technology outsourcing to help repair the best value of the shaft, but to pay high maintenance costs and transportation costs.

Traditional disadvantages: 1. Temporary measures are mostly emergency improvisation, which are not reasonable, and have no long-term effect and safety at all;

2. Due to the influence of thermal stress, the material is injured and deformed, and the uncentered operation is easy to cause major accidents;

3. The mechanical relationship cannot be solved, and it is easy to wear and tear again;

4. Some parts have no means to deal with them, and excessive scrapping and replacement and the need for inventory affect the capital flow of the enterprise;

5. Time-consuming, laborious, and the accuracy of tooling does not meet the requirements;

6. A large number of scrapped replacements have increased the operating costs of enterprises.

2. Polymer composite material repair:

At present, Europe, the United States, Japan and South Korea generally use polymer composite materials technology and nanotechnology.

Because the metal material is a "constant relationship", although the strength is higher, but the impact resistance and concession are poor, so the long-term operation will cause the matching clearance to continue to increase and cause shaft wear, after realizing this key reason, the polymer composite materials developed by the European and American new technology research institutions have the strength and hardness required by the metal, and have the concession (variable relationship) that the metal does not have, through the "mold repair", "component correspondence", "machining" and other processes, It can ensure the dimensional fit of the repair part and the mating part to the greatest extent;

In industrial production, machinery and equipment are used more, in use, due to a variety of reasons, such as: shaft and pulley or coupling improper matching, long-term overload operation, sliding bearing journal due to poor lubrication, lubricating oil with iron filings, sand and other impurities or because the manufacturing quality is not high, heat treatment can not meet the requirements, or the shaft is hit by external force and other causes journal wear, serious and even caused journal breakage.