35. Travel Mechanism || free download 3D model

Link to download 3D model

http://velocicosm.com/3B19

Simulation: 

Application Overview

Purpose

• Operation
  • The cylinder drives the spur gear along the fixed rack. The spur gear also propels the moving gear forward to extend the stroke.
  • The cylinder stroke can be doubled by utilizing a rack and pinion mechanism.

Target workpiece

• Shape: Block
• Material: Tungsten
• Workpiece size: 50 x 50 x 100mm

Design Specifications

Operating Conditions or Design Requirements

• Cylinder outstroke: 50mm
• Travel of the moving rack: 100mm
• External dimension: L340 x W132 x H94mm

Required Performance

• Load: 48N

Selection Criteria for Main Components

• Select wear resistant materials for the racks and pinion.

Design Evaluation

Verification of main components

• Validate the cylinder output
  • Condition values.
  Where the cylinder inner diameter is 20 mm, the plant air pressure=0.5MPa
  Cylinder thrust (outstroke): 157N
  Cylinder thrust (instroke): 132N
  Mass of workpiece (M₁): 4.8kg , mass of worktable (M₂): 1.17kg
  Friction coefficient of linear guide (μ): 0.005, gravitational acceleration (g): 9.8m/s²
  Cylinder stroke (sｔ₁): 50mm
  Rack travel (sｔ₂): 100mm
  Required cylinder thrust: Fc. 
  Load applied by the workpiece: F₁
  • Law of conservation of work load .
  Assuming that the work loads of the cylinder and the rack are equivalent,
  Fc×st₁=F₁×st₂
  Fc=F₁×st₂/st₁
  • the load applied by the workpiece, F₁, is
  F F₁=(M₁+M₂)×g×μ=(4.8+1.17)×9.8×0.005=0.29N
  • In consequence, the required cylinder thrust, Fc, is
  Fc=0.29×0.1/0.05 (Fc=0.58N)
  • Conclusion.
  Cylinder thrust (instroke): 132N>>0.58N For the expressions described above, it can be concluded that the thrust is sufficient.

Other Design Consideration

• The positions of the racks and the pinion should be adjusted using mounting holes (whose diameter is larger than the thread diameter) and shims.