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How much do you know about jaw crushers?
- 2021-04-16 -

Jaw crusher, as a coarse crushing process in the production line, can crush nearly 200 kinds of materials, whether it is limestone, gypsum, coal gangue, quartz sand and other low-hardness materials, or granite, barite, iron ore, These high-hardness materials such as river pebbles can be coarsely crushed and are used in various fields such as mines, construction, highways, garbage crushing, etc. This eye-catching jaw crusher has become a symbol of coarse crushing in the entire crushing industry. 


Features of Jaw Crusher

a. Any block material can be crushed, without the need to process the materials before crushing, which saves customers a lot of costs.

b. The design of the crushing cavity is relatively deep, and the effect of energy saving and consumption reduction is very significant, which improves the crushing efficiency of the equipment and the passing capacity of materials.

c. The particle size of the crushed material is very uniform, and the output particle size can be easily adjusted, and the adjustment range is still very large, thereby meeting the construction requirements of the processing plant.

d. Long service life. It is made of high-quality materials, so that the friction between parts and components during the working process of the equipment is very small, which not only reduces maintenance costs, but also extends the service life of the equipment by 3-5 year.


Working principle of jaw crusher

When the jaw crusher is working, the movable jaw plate cyclically reciprocates against the fixed jaw plate, sometimes approaching and sometimes leaving. When approaching, the material is crushed by squeezing, splitting, and impact between the two jaws; when leaving, the crushed material is discharged from the discharge port by gravity.

In the process of crushing huge rocks into small rocks, the first crusher is usually the main crusher. The longest and most robust crusher is the jaw crusher. When feeding the jaw crusher, the material is poured into the crushing chamber containing the jaw teeth from the top entrance, and the jaw teeth push the material against the chamber wall with huge force, breaking it into smaller stones. Supporting the movement of the jaw teeth is an eccentric shaft, and this eccentric shaft penetrates the frame of the fuselage. Eccentric motion is usually produced by flywheels fixed at both ends of the shaft. Spherical roller bearings are often used in flywheels and eccentric support bearings. The bearings must withstand huge impact loads, abrasive sewage and high temperatures.

jaw crusher

Maintenance and maintenance of jaw crusher

The working environment of the jaw crusher is complicated. The main work is to crush the stone with relatively high hardness. The working time is long, the environment is relatively harsh, and the jaw plate is worn during operation. The wear-resistant parts are replaced more frequently. What are the matters needing attention when maintaining, slippery and wearing parts?

Jaw crusher maintenance - jaw crusher disassembly

The thrust plate, which is the toggle plate, is the most frequently replaced jaw crusher. For crushers with integral connecting rods, the thrust plate must be removed, the baffle bolts must be unscrewed, the dry oil lubricating pipes are cut off, the thrust plate is hung on the crane hook or other lifting equipment, and then the horizontal tie rods can be loosened. The spring at one end pulls the movable jaw to the direction of the fixed jaw and takes out the thrust plate. If you want to take out the rear thrust plate, you should pull the connecting rod, the front thrust plate and the movable jaw together, and take out the rear thrust plate.
After the thrust plate is removed, cut off the thin oil lubrication pipe and the cooling water pipe, support it with a bracket under the connecting rod, and then remove the connecting rod cover to lift the connecting rod.

The main shaft of the crusher should be removed together with the pulley and flywheel, move the motor (along with the belt) along the slide rail as close as possible to the crusher, and remove the triangle belt. Then lift the shaft with a crane.

In order to disassemble the movable jaw, you must first cut off the dry oil lubricating pipe, disassemble the tie rod, remove the bearing cap, and then use a crane or other lifting equipment to pull the movable jaw out.

Precautions for replacement of wear parts of jaw crusher

In the jaw crusher, the liner, thrust plate and eccentric shaft are the main wear parts. The service life of the jaw crusher wear parts is shown in the figure below. The following introduces the precautions for the replacement of these wear parts.

1. Replacement of liner

The fixed jaw lining plate (tooth plate), movable jaw lining plate (tooth plate), and lining plates (guard plates) on both sides of the jaw crusher are most prone to wear. If the abrasion is severe, the particle size of the product will become larger. When the liner is initially worn, the liner can be turned around, or the upper and lower parts can be turned around. The wear of the jaw plate is mostly concentrated in the middle and lower parts. When the tooth plate is worn out by 3/5, a new liner needs to be replaced. When the lining plates on both sides wear out by 2/5, they also need to be replaced with new ones.

2. Replacement of mandrel, eccentric shaft and bearing bush

If there is not much shaft wear and just want to repair the geometric shape, you can get it for turning on a lathe, but when the journal size is reduced by 5% compared to the original after several turnings, turning is not allowed and should be replaced with a new one.
Since the jaw crusher works under impact load, the babbitt alloy lining on the bearing bush needs to be recast every two years.
If the eccentric shaft and the bearing bush, the mandrel and the bearing bush are worn, and the gap is greater than 1.5 times the original assembly clearance, it needs to be adjusted or replaced; the oil groove is worn 1.5 mm, the oil groove should be reopened and adjusted; the upper cover of the connecting rod head When the gap between the eccentric shaft and the eccentric shaft is worn to more than 1.5 times the assembly gap, it is also necessary to add pads for adjustment or replace with a new one.

3. Replacement of thrust plate

When the thrust plate is severely worn or the front thrust plate is broken, the ore in the crushing chamber must be removed first, the severely worn or broken thrust plate must be taken out, and the movable jaw and the toggle plate on the connecting rod must be checked for damage. Then pull the movable jaw to the vicinity of the fixed jaw, lubricate the working surface of the toggle plate with dry oil, replace it with a new thrust plate, make it slowly contact the working surface of the toggle plate, and tighten the horizontal pull rod to make the movable jaw handle thrust The board is clamped. Tighten the safety cover, connect the lubrication system, and then adjust the size of the discharge port.

How to extend the service life of jaw crusher liner

The design and material selection of the jaw crusher is the basis for the service life of the jaw.

When designing the jaw plate: the tooth peak and the tooth valley should be opposite between the moving and fixed jaw plates to ensure that the jaw plate can exert a certain bending stress in addition to the corresponding squeezing force on the material during work, and improve the jaw fracture. The crushing ability.
For small and medium-sized jaw breakers, in order to extend the service life of the jaw plate, the jaw plate can be designed in a symmetrical shape, so that it can be turned around when the lower part is severely worn.

For large jaw crushers, the jaw plates can be designed to be symmetrical to each other, so that the wear blocks can be exchanged easily and the service life of the jaw plates can be prolonged.

When selecting materials for the jaw plate: ZGMn13 can be used as the main material for the material selection. This manganese steel has strong toughness, although its hardness is reduced, but it has the characteristics of cold work hardening. It is squeezed when the jaw crusher is working. The force causes it to be continuously squeezed and hardened during the working process, so as to realize the hardening while being worn out until it is worn out to the limit of use before it is scrapped. In addition, other factors such as cost must be considered comprehensively when selecting materials.

  • Attention to the assembly of jaw plate of jaw crusher

The assembly of the jaw plate has a great influence on its service life. When assembling the jaw plate, it is necessary to firmly fix the jaw plate on the movable and fixed jaws, and use copper, lead, zinc, etc. to maintain the same parallelism between the movable and fixed jaws. In order to avoid the relative sliding between the jaw plate and the movable and fixed jaws when the jaw crusher is working, the jaw plate will be worn or broken, thereby reducing the service life of the jaw plate of the jaw crusher.

  • Matters needing attention when using the equipment

During the working process of jaw crushing, the material is in direct contact with the jaw plate, and the jaw plate bears huge crushing pressure, especially for some materials with higher hardness. The strong force will cause the installation bolts of the jaw plate to be vibrated and loosen, thereby aggravating the wear of the jaw plate, or even falling off or breaking.

When this happens, it is impossible to solve the problem only by tightening the fastening bolts of the jaw plate before the jaw crusher is turned on. It is necessary to deal with the causes of the loosening and falling off during the working process of the jaw crusher. Specific analysis and adopt practical methods to solve it.

For example, springs can be added to the fixing bolts to improve the anti-loosening and vibration reduction ability of the jaw plate fixing bolts, extend the service life of the jaw plate, and improve the production efficiency and economic benefits of the jaw crusher.



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