Basic mechanical structure of jaw crusher introduction

Basic mechanical structure of jaw crusher introduction

Overview

A jaw crusher is composed of dozens of mechanical parts, which can be divided into seven core assembly modules: frame assembly, driving transmission assembly, crushing working assembly, adjusting discharging assembly, safety protection assembly, tension reset assembly and lubrication auxiliary assembly. Every component cooperates closely to finish rock extrusion crushing. This article systematically introduces each basic mechanical structure and its core functions.

1. Main Frame Assembly

The frame is the load-bearing base of the whole jaw crusher, usually cast with thick high-strength steel or welded steel plates.
  • Front frame: Installs fixed jaw plate, forms one side of the V-shaped crushing cavity, bears huge impact extrusion force from stones.
  • Rear frame: Mounts adjusting seats, bearing bases and tension spring brackets, connects with front frame via bolts.
  • Side guard plates: Seal both sides of the crushing cavity, prevent stone splashing and reduce frame abrasion.
Function: Bear all impact, compression and vibration loads during long-time crushing operation, ensure overall structural stability.

2. Crushing Working Assembly (Core Crushing Parts)

This module directly contacts raw stones and performs crushing work, including fixed jaw and movable jaw assemblies.

Fixed Jaw Part

  • Fixed jaw plate: Wear-resistant high manganese steel tooth plate, tightly fixed on front frame, static crushing surface. Tooth ridges on the surface increase splitting force on rocks.
  • Wedge fixing blocks: Lock jaw plate tightly to avoid loosening under strong impact.

Movable Jaw (Swing Jaw) Part

  • Swing jaw body: Heavy casting support structure, sleeves on eccentric shaft and swings back and forth.
  • Movable jaw plate: Matches fixed jaw plate to form the extrusion pair, same wear-resistant material as fixed jaw plate, quick-wear spare part.
  • Jaw plate fixing bolts: Fasten tooth plates for easy disassembly and replacement after wear.
Function: Form variable-volume V-shaped crushing cavity; reciprocating extrusion crushes all hard bulk materials.

3. Driving & Transmission Assembly (Power Source Module)

Transmit motor rotation power to drive swing jaw reciprocation, the power core of equipment.
  1. Driving motor: Three-phase asynchronous motor, provides rotary power source.
  2. V-belt pulley & triangular belts: Connect motor shaft and flywheel, transmit torque and buffer vibration.
  3. Flywheel: Two heavy metal wheels installed at both ends of eccentric shaft. Stores kinetic energy during idle return stroke and releases energy during heavy-load crushing stroke, stabilizing motor load fluctuation.
  4. Eccentric shaft: Key transmission part passing through swing jaw top. Its offset cam converts circular rotation of flywheel into horizontal swing of movable jaw. Equipped with rolling bearings at both ends for smooth rotation.

4. Toggle Plate & Safety Protection Assembly

Dual functions: force transmission and overload safety protection, an exclusive structural design of jaw crushers.
  • Toggle plate: Cast iron plate with pre-set weak fracture notches. One end props swing jaw bottom, the other contacts adjusting seat. Transmits thrust to push movable jaw close to fixed jaw during compression stroke.
  • Toggle seats: Metal brackets fixed on adjusting base, support toggle plate and disperse pressure.
Safety mechanism: When uncrushable metal foreign blocks enter cavity and cause overload, toggle plate breaks off at pre-groove position automatically. Thrust to swing jaw disappears instantly to avoid damage to high-cost eccentric shaft, bearings and frame. Only low-cost toggle plate needs replacement after overload accident.

5. Discharge Opening Adjustment Assembly

Installed at the machine rear, used to change bottom gap size and control finished stone particle size.
  • Adjusting wedge blocks: Two pairs of upper and lower wedges; pushing wedges forward or backward changes the horizontal position of toggle seat.
  • Adjusting bolts & hand wheels: Manually control wedge displacement during shutdown.
  • Adjusting base: Fixed carrier for toggle seat and wedge blocks.
Working logic: Move toggle seat forward → narrow discharge gap → finer crushed aggregate; pull toggle seat backward → widen gap → coarse finished stones. All adjustments must be carried out with machine power off.

6. Tension Reset Assembly

Realize automatic return of swing jaw after each compression stroke, forming continuous circulation crushing.
  • Tension spring: High-strength compression spring installed at rear bottom of frame.
  • Tie rod (pull rod): Long steel bar connects spring and swing jaw lower part.
Working process: When eccentric shaft rotates to release position, compressed spring rebounds and pulls swing jaw away from fixed jaw via tie rod, expanding crushing cavity for stone discharging.

7. Lubrication Auxiliary Mechanical Structure

Reduce friction loss of high-speed moving joints, extend service life of bearings and shafts.
  • Bearing housings & sliding bearings: Support eccentric shaft rotation; bear heavy radial impact load.
  • Grease filling nozzles / thin oil circulation pipeline: Regularly inject lubricating oil or grease to form isolation oil film between metal contact surfaces.
  • Oil baffle seals: Prevent dust, stone powder and water from entering bearing chamber to avoid bearing ablation.

Additional Auxiliary Matching Structures

  1. Dust-proof cover: Reduce flying dust during feeding and crushing, meet environmental protection requirements.
  2. Anti-splash baffle: Block stone splashing from feeding inlet for operation safety.
  3. Base support legs: Fix whole crusher on concrete foundation, disperse vibration.

Structural Cooperation Full Working Logic Summary

  1. Motor drives flywheel and eccentric shaft to rotate; eccentric shaft pushes swing jaw forward via toggle plate.
  2. Fixed jaw and movable jaw squeeze stones inside V cavity to realize crushing.
  3. After one compression stroke, tension spring pulls swing jaw back through tie rod, qualified stones drop from bottom discharge opening.
  4. Adjust rear wedge assembly to change toggle plate position, control discharging particle size.
  5. Lubrication system protects eccentric shaft bearings from high-temperature wear during continuous operation.
  6. Once overload occurs, toggle plate fractures to cut off thrust and protect main machine core components.