How to disassemble a jaw crusher? What is the life of wear parts and how to replace them? All the answers are here!

Due to long-term operation in harsh working environments, jaw crushers need to crush hard ores, stones, etc., resulting in significant wear and frequent replacement of wear-resistant parts. Spare parts need to be prepared to avoid delaying production, which involves the disassembly of jaw crushers, replacement of wear-resistant parts, and the quantity of spare parts.

01

Dismantling of jaw crusher

The thrust plate, also known as the elbow plate, is frequently replaced in jaw crushers. The crusher with integral connecting rod must remove the thrust plate. First, unscrew the baffle bolt, cut off the lubricating oil pipe, hang the thrust plate on the crane hook or other lifting equipment, and then release the spring at one end of the horizontal rod, pull the movable jaw in the direction of the fixed jaw, and remove the thrust plate. If you want to remove the rear thrust plate, you should pull the connecting rod together with the front thrust plate and the moving jaw to remove the rear thrust plate.

After removing the thrust plate, cut off the thin oil lubrication pipe and cooling water pipe, support them with a bracket under the connecting rod, and then remove the connecting rod cover before lifting out 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) as close as possible to the crusher along the slide rail and remove the V-belt. Then use a crane to lift the shaft.

In order to disassemble the moving jaw, it is necessary to first cut off the lubricating oil pipe, remove the pull rod, take off the bearing cover, and then use a crane or other lifting equipment to pull out the moving jaw.

02

Precautions for replacing wear-resistant parts of jaw crusher

In the jaw crusher, the lining plate, thrust plate, and eccentric shaft are the main wear-resistant parts, and the service life of the jaw wear parts is shown in the following figure. Below are some precautions for replacing these wear-resistant parts.

1. Replacement of lining plate

The fixed jaw liner (toothed plate), movable jaw liner (toothed plate), and side liner (protective plate) of the jaw crusher are prone to wear and tear. If the wear is severe, it will lead to an increase in the particle size of the product. When the lining plate is initially worn, it can be turned around for use, or the upper and lower parts can be turned around for use. The wear of the jaw plate is mostly concentrated in the middle and lower parts. When 3/5 of the tooth plate is worn off, a new lining plate needs to be replaced. When 2/5 of the lining plates on both sides are worn out, they also need to be replaced with new ones.

2. Replacement of spindle, eccentric shaft, and bearing shell

If there is not much wear on the shaft and you only want to repair the geometric shape, you can take it to a lathe for turning. However, when the journal size is reduced by 5% after several turns, it cannot be turned again and should be replaced with a new one.

Due to the fact that the jaw crusher operates under impact loads, the Babbitt alloy lining on the bearing needs to be recast every two years.

If the eccentric shaft and the bearing shell, or the central shaft and the bearing shell are worn and the clearance is greater than 1.5 times the original clearance, additional pads need to be added for adjustment or replacement; The oil groove has worn 1.5 millimeters and should be reopened and adjusted; When the gap between the upper cover of the connecting rod head and the eccentric shaft is worn to more than 1.5 times the assembly gap, it also needs to be adjusted with padding or replaced 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, and the severely worn or broken thrust plate should be removed to check whether the elbow plate on the moving jaw and connecting rod is damaged. Then pull the movable jaw near the fixed jaw, lubricate the working surface of the elbow plate with dry oil, replace it with a new thrust plate, slowly contact it with the working surface of the elbow plate, and tighten the horizontal pull rod to clamp the thrust plate with the movable jaw. Tighten the safety cover, connect the lubrication system, and adjust the size of the ore discharge port.

03

How to extend the service life of the lining board

1. Reasonable design and material selection

The design and material selection of the jaw plate are the basis for the service life of the jaw plate.

When designing jaw plates:

The tooth peaks and valleys between the moving and fixed jaw plates should be opposite to each other to ensure that the jaw plate can apply a certain bending stress in addition to the corresponding squeezing force on the material during operation, thereby improving the crushing ability of the jaw.

For small and medium-sized jaw fractures, 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 for use when the lower part is severely worn.

For large jaw fractures, the jaw plate can be designed as several symmetrical pieces, making it easy to replace the worn pieces and extend the service life of the jaw plate.

When selecting materials for jaw plates:

ZGMn13 can be used as the main material for material selection. This manganese steel has strong toughness, although it reduces its hardness, it has the characteristic of cold work hardening. When the jaw crusher crushes the plate during operation, the compressive force it bears continuously hardens it during operation, thus achieving simultaneous wear and hardening until it exceeds the limit of use before being scrapped. In addition, when selecting materials, other factors such as cost should also be considered comprehensively.

2. Assembly precautions

The assembly of jaw plates has a significant impact on their service life. When assembling the jaw plate, it is necessary to firmly fix the jaw plate on the moving and fixed jaws, and use copper sheets, lead, zinc, etc. to maintain the same parallelism between the moving and fixed jaw plates. To avoid wear or breakage of the jaw plate caused by relative sliding between the jaw plate and the moving or fixed jaw during jaw crushing work, thereby reducing the service life of the jaw plate of the jaw crusher.

3. Make appropriate improvements during use

During the process of jaw fracture, the material comes into direct contact with the jaw plate, which bears enormous crushing pressure, especially for materials with higher hardness. The strong force can cause the installation bolts of the jaw plate to loosen due to vibration, thereby exacerbating the wear of the jaw plate, and even causing it to fall off or break.

When this situation occurs, simply tightening the fastening bolts of the jaw plate before starting the jaw crusher cannot solve the problem. It is necessary to conduct a specific analysis of the causes of looseness and detachment of the jaw crusher plate during its operation and adopt practical and feasible methods to solve it. For example, springs can be installed on the fixed 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.