A jaw crusher consists of several main assemblies, including the frame, jaw plates and cheek plates, drive system, adjustment mechanism, flywheel, and lubrication system. These components work together to compress and crush material, control product size, and discharge the finished material.
Jaw crusher models differ in structural design, component materials, and assembly methods. For example, the frame may use a cast or welded construction, while the bearings may be rolling or plain bearings depending on the design. Understanding the construction and function of each component helps with equipment selection, routine maintenance, and replacement part planning.
Crusher frame
The crusher frame is the main load-bearing structure of a jaw crusher. It supports the eccentric shaft, bearings, moving jaw, and other working components while resisting the impact loads and reaction forces generated during crushing.
The frame is generally designed as a rigid structure with sufficient strength and stiffness to maintain stability during continuous operation.
Depending on the crusher model and design requirements, the frame may be manufactured as a single casting, a sectional casting assembly, or a welded steel structure. Some modern jaw crushers also use non-welded cast frame sections connected by pins and bolts. These construction methods differ in structural design, manufacturing processes, and maintenance requirements.
For large crushers, the frame design must also account for transportation, on-site assembly, and overall load distribution. Welded frames require attention to weld quality, structural deformation, and post-weld stress relief.
Jaw plates and cheek plates
Jaw plates are the main crushing components that come into direct contact with the feed material. They consist of a fixed jaw plate and a movable jaw plate.
The fixed jaw plate is mounted on the stationary support at the front of the frame, while the movable jaw plate is attached to the moving jaw body. During operation, the moving jaw plate reciprocates under the drive mechanism, working against the fixed jaw plate to compress and break the material.
Jaw plates are commonly manufactured from wear-resistant materials such as manganese steel to withstand repeated compression and impact loads. Different tooth profiles can be selected according to material properties and production requirements to improve material gripping and crushing performance.
Cheek plates, also called side liners, are installed along the sides of the crushing chamber. They protect the inner frame surfaces from direct contact with abrasive material. Both jaw plates and cheek plates must be securely fastened to prevent loosening or displacement during operation.
Drive system
The drive system of a jaw crusher mainly consists of an electric motor, belt drive, eccentric shaft, bearings, and moving jaw. The eccentric shaft is the main component responsible for producing the movement of the moving jaw.
The motor drives the eccentric shaft through V-belts and pulleys. The eccentric section of the shaft converts rotational motion into reciprocating movement of the moving jaw. This causes the movable jaw plate to periodically approach and move away from the fixed jaw plate, producing the compression required for crushing.
The eccentric shaft is subjected to considerable bending and torsional loads. Its material and structural design must meet the operating requirements of the crusher. Some models use forged alloy steel shafts, followed by precision machining and appropriate heat treatment to achieve the required strength and dimensional accuracy.
Bearings support the eccentric shaft and related moving components. Common arrangements include rolling bearings and plain bearings, depending on the equipment design. Bearing fit, lubrication, and sealing all affect the operating stability of the drive system.
Adjustment mechanism
The adjustment mechanism controls the width of the discharge opening and therefore affects the finished product size. Different jaw crushers use different adjustment arrangements, including shim adjustment, wedge adjustment, and hydraulic adjustment.
With shim adjustment, the discharge opening is changed by adding or removing shims of specified thickness at the rear adjustment assembly. This changes the position of the toggle support and adjusts the opening.
Wedge adjustment uses the relative movement of two wedges to change the distance between the moving and fixed jaws. Depending on the machine configuration, the wedges may be operated mechanically or hydraulically.
The toggle plate and toggle seats are also important components of the support and adjustment mechanism. The toggle plate supports the lower part of the moving jaw and transmits movement and crushing loads. Some designs also use it as an overload protection component. If uncrushable metal enters the crushing chamber, a specially designed toggle plate may fracture first to limit damage to other major components.
Flywheel and drive pulley
The flywheel and drive pulley are major rotating components of a jaw crusher, but they perform different functions.
The flywheel stores and releases rotational energy. A jaw crusher operates through cyclic compression, so the machine load changes during different stages of the crushing cycle. The flywheel uses its rotational inertia to smooth these load fluctuations and help maintain more stable eccentric shaft rotation.
The drive pulley transfers power from the electric motor to the eccentric shaft. Some jaw crusher models use separate flywheels and pulleys, while others integrate the relevant functions into a common rotating assembly.
The flywheel and pulley must maintain proper balance and installation alignment during operation. Manufacturing and maintenance inspections should check for cracks, deformation, loose mounting bolts, and worn pulley grooves. Balancing inspections should follow the equipment manufacturer's requirements.
Lubrication system
The lubrication system reduces friction between bearings and moving components, limits wear, and controls operating temperature. It is an important part of maintaining reliable jaw crusher operation.
Depending on the machine design, the eccentric shaft bearings may use grease lubrication or a circulating oil system. In grease-lubricated arrangements, a lubrication device supplies grease to the bearings. Circulating oil systems use pumps, pipelines, and associated filters to deliver oil continuously. Some designs also use the circulating oil to help remove heat from the bearings.
For jaw crushers with plain bearings, the bearing shells may include oil grooves or channels to improve lubricant distribution across the contact surfaces. Some arrangements also use forced lubrication to maintain an adequate oil supply during operation.
The lubrication requirements of the toggle plate, toggle seats, bearings, and other moving connections also depend on the design. Some toggle support systems use rolling contact and do not require additional lubrication. Maintenance personnel should therefore follow the equipment manual when determining lubrication points, lubricant types, and application intervals rather than applying manual lubrication to every component.
The structural design and manufacturing quality of the main jaw crusher components directly affect equipment stability and service life. For non-standard mechanical parts such as frames, eccentric shafts, bearing housings, and connecting brackets that require drawing-based manufacturing, Hansheng Automation provides custom precision machining according to customer drawings and machining requirements.
Beyond crushing equipment components, our machining services also cover functional parts for tobacco packaging and filling machinery, as well as precision fittings for yacht equipment and structural components for RC racing cars. Components are manufactured according to the specific design and manufacturing requirements of each application.
