Elastic buffer device principle of jaw crusher

Elastic buffer device principle of jaw crusher

Jaw crushers generate periodic strong impact, vibration and reciprocating shock during continuous ore extrusion. The elastic buffer device relies on elastic deformation (metal spring compression, rubber viscoelastic energy absorption) to absorb instantaneous impact energy, buffer rigid collision between moving parts, isolate vibration transmission and protect core components.

There are two core elastic buffer systems on standard jaw crushers:

  1. Tension spring & tie rod buffer assembly (built-in motion reset buffer, mandatory for all PE/PEV jaw crushers)
  2. Rubber elastic shock-absorbing base buffer (external foundation isolation buffer, widely used on modern heavy-duty European jaw crushers)

1. Tension Spring & Tie Rod Internal Elastic Buffer (Core Motion Buffer)

1.1 Structural Composition

High-strength compression tension spring, long steel tie rod, spring lock nuts, limit baffle, swing jaw lower connecting lug. Installed at the rear bottom of the crusher frame, connected between swing jaw and rear frame baffle.

1.2 Basic Elastic Mechanics Principle

Based on Hooke’s elastic deformation law: the spring stores elastic potential energy under compression, and releases rebound force when unloading to realize swing jaw reset + impact buffering dual functions.

Complete cyclic buffer working process:

Stage 1: Crushing stroke (spring compressed, energy storage & impact buffering)

Eccentric shaft pushes swing jaw forward to squeeze hard ore; huge reverse thrust pulls the swing jaw bottom backward. The tie rod compresses the tension spring, and the spring absorbs part of the instantaneous crushing impact energy through elastic compression deformation.
  • Buffer effect: Avoid rigid hard collision between toggle plate, toggle seat and swing jaw lug; eliminate metal knocking noise during heavy-load crushing; reduce instantaneous impact load transmitted to eccentric shaft bearings.

Stage 2: Discharge return stroke (spring rebound, energy release & reset driving)

After rock fragmentation, the swing jaw loses forward thrust. The compressed spring releases stored elastic potential energy, pulls the swing jaw backward rapidly via tie rod to widen the crushing cavity for material discharge.
  • Secondary buffer: The spring’s gradual rebound speed limits the swing jaw’s backward impact stroke, preventing the toggle plate from violently hitting the adjusting seat and causing wear or fracture.

1.3 Three Core Buffer Functions of Tension Spring Assembly

  1. Reciprocating motion reset power source: Realize automatic cycle crushing of swing jaw without extra driving force.
  2. Instant impact energy absorption: Offset peak shock force when squeezing large hard ore, reduce fatigue damage of frame and swing jaw casting.
  3. Toggle plate anti-falling limit buffer: Maintain constant pre-tightening force to keep toggle plate tightly fitted with two contact seats; prevent toggle plate from sliding off under vibration during long-term operation.

1.4 Spring Pre-tightening Adjustment Rule

The spring lock nut must be adjusted to maintain moderate pre-compression:
  • Over-tightened spring: Excessive elastic resistance increases motor load, raises power consumption, accelerates spring fatigue fracture.
  • Over-loose spring: Insufficient buffer capacity, obvious metal collision noise, toggle plate easy to slip and break frequently.

2. Rubber Elastic Base Buffer (External Vibration Isolation Buffer)

2.1 Structural Composition

High-damping rubber elastic pads, steel limit baffles, anchor bolt flexible sleeves, installed between crusher frame base and concrete foundation.

2.2 Vibration Isolation Buffer Principle (Viscoelastic Energy Dissipation)

Jaw crusher’s periodic swing produces continuous low-frequency vibration, which will transmit to the concrete foundation and surrounding equipment through rigid steel contact, causing foundation cracking, bolt loosening and adjacent machine failure.

The rubber buffer pad uses viscoelastic material characteristics:

  1. Elastic deformation absorbs vertical and horizontal vibration shock generated during crushing;
  2. Internal molecular friction of rubber converts vibration kinetic energy into heat energy for dissipation, realizing vibration isolation;
  3. Progressive stiffness design: Soft elastic deformation under normal light load for stable vibration reduction; automatically hardens under ultra-large peak impact to avoid full compression bottoming failure.

2. Core Advantages of Rubber Base Buffer

  1. Cut off rigid vibration transmission between equipment and foundation, reduce foundation fatigue damage;
  2. Buffer horizontal sliding impact when feeding oversized ore blocks, stabilize the whole machine position without frequent anchor bolt loosening;
  3. Reduce vibration noise of the whole production line, meet environmental protection noise standards;
  4. No rigid metal friction, longer service life than traditional steel spring shock absorbers.

3. Auxiliary Local Elastic Buffer Components (Small Auxiliary Cushions)

3.1 Toggle Plate Rubber Buffer Cushions

Elastic polyurethane/rubber gaskets installed at arc contact heads on both ends of toggle plate.
  • Buffer principle: Fill tiny assembly gaps, absorb local contact impact when toggle plate transmits thrust; uniform stress distribution to prevent toggle plate edge cracking under point load.

3.2 Motor Base Elastic Cushion

Elastic rubber pads under motor support frame, buffer vibration transmitted from flywheel V-belt to motor, protect motor bearing and stator winding from vibration damage.

4. Unified Working Logic of All Elastic Buffer Devices

All elastic buffer parts follow the same energy conversion principle:

Crushing impact mechanical kinetic energy → elastic deformation potential energy storage → slow energy release / internal friction heat dissipation → eliminate instantaneous rigid shock

Without elastic buffer devices:

  • Severe metal collision between swing jaw, toggle plate and frame;
  • Sharp vibration leads to frequent bolt loosening, bearing ablation, frame crack;
  • Toggle plate premature fatigue fracture, frequent unplanned shutdown maintenance.

5. Common Failures of Elastic Buffer Devices & Principle Analysis

  1. Tension spring permanent plastic deformation / breakage

    Cause: Long-term overload compression exceeds elastic limit, loss of buffer reset capacity.

    Failure performance: Swing jaw cannot reset automatically, toggle plate falls off, violent metal knocking sound during operation.

  2. Rubber buffer pad aging hardening / cracking

    Cause: Long-term high vibration, dust erosion and high temperature loss viscoelasticity.

    Failure performance: Vibration isolation failure, foundation resonance, loose anchor bolts.

  3. Insufficient spring pre-tightening

    Cause: Long-term vibration loosens lock nut, buffer elastic force drops.

    Failure performance: Toggle plate jumps during crushing, frequent fracture, uneven discharge particle size.

Full Principle Summary

The jaw crusher’s elastic buffer system is divided into internal motion tension spring buffer and external rubber vibration isolation base buffer:
  1. Tension spring assembly realizes swing jaw reciprocating reset, absorbs instantaneous crushing impact energy to protect transmission and crushing core parts;
  2. Rubber elastic base blocks vibration transmission between the whole machine and foundation, dissipates continuous vibration energy to avoid foundation and auxiliary equipment damage;
  3. Small local elastic cushions at toggle plate and motor base eliminate local point contact impact, optimize overall equipment stress distribution.

    All elastic buffer components rely on elastic deformation energy storage and dissipation to reduce rigid shock and vibration, greatly extend the service life of jaw crusher’s wearing parts and cast frame.