INDUSTRY COMPONENT

Keyway

A keyway is a precision slot machined into a shaft or hub to accommodate a key, ensuring positive torque transmission and alignment in mechanical assemblies.

View Specifications

Component Specifications

Definition
A keyway is a longitudinal groove or slot precisely machined into the bore of a hub or the surface of a shaft, designed to house a parallel or Woodruff key. In polypropylene injection molded gear wheels, the keyway is typically molded into the gear hub during manufacturing to create a positive mechanical connection with the shaft, preventing relative rotation and ensuring accurate power transmission. The keyway's dimensions must maintain strict tolerances to match standard key sizes while accounting for material properties like shrinkage and thermal expansion in plastic components.
Working Principle
The keyway works by providing a recess for a key that fits into both the shaft and the hub of the gear wheel. When torque is applied, the key transmits rotational force from the shaft to the gear (or vice versa) through shear stress across the key's sides, preventing slippage. In polypropylene gears, the molded keyway must distribute stress evenly to avoid localized deformation or cracking, relying on the plastic's resilience and the key's mechanical interference fit.
Materials
Polypropylene (PP), typically homopolymer or copolymer grades with additives for enhanced strength, wear resistance, and dimensional stability. Common specifications include PP with 20-40% glass fiber reinforcement for improved mechanical properties, or mineral-filled PP for cost-effective applications. Material must comply with standards like ISO 1873-1 or ASTM D4101.
Technical Parameters
  • Draft Angle 0.5-1° for mold release in injection molding
  • Hub Diameter Matches standard shaft sizes (e.g., 10 mm, 12 mm, 15 mm)
  • Keyway Depth Typically 0.5-2.0 mm, depending on shaft diameter and torque requirements
  • Keyway Width Standard sizes per ISO 773: e.g., 3 mm, 4 mm, 5 mm
  • Surface Finish Ra ≤ 3.2 μm to reduce stress concentrations
  • Tolerance Class ISO 773 tolerance class H9 for plastic components
Standards
ISO 773, DIN 6885, ISO 286-2

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Keyway.

keyway polypropylene gear injection molding torque transmission mechanical key shaft connection plastic gear design ISO 773 DIN 6885 Keyway in Rubber and Plastic Product Manufacturing

Parent Products

This component is used in the following industrial products

Polypropylene Injection Molded Gear Wheel

Precision plastic gear component manufactured via injection molding for mechanical power transmission.

View Product Details

Centrifugal Pump Impeller

Rotating component that transfers energy to fluid in centrifugal pumps.

View Product Details

Heavy-Duty Rolling Mill Work Roll

Core rotating cylinder that directly contacts and shapes hot steel during rolling

View Product Details

Engineering Analysis

Risks & Mitigation
  • Stress concentration at keyway corners leading to cracking
  • Wear and deformation under high torque loads
  • Misalignment due to molding defects or shrinkage
  • Thermal expansion mismatch with metal shafts causing looseness
FMEA Triads
Trigger: Sharp corners or inadequate fillet radius in keyway design
Failure: Crack initiation and propagation in polypropylene hub
Mitigation: Design keyways with minimum 0.5 mm radius fillets, use stress analysis software, and select reinforced PP grades
Trigger: Excessive torque exceeding material yield strength
Failure: Shear failure of keyway walls or key deformation
Mitigation: Calculate torque limits based on material properties, oversize keyway dimensions, or use metal inserts in high-load applications
Trigger: Molding defects like voids or sink marks in keyway area
Failure: Reduced mechanical strength and premature failure
Mitigation: Optimize injection molding parameters (pressure, temperature), ensure proper gate location, and implement quality control inspections

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
Keyway width tolerance: H9 per ISO 286-2, depth tolerance: ±0.1 mm for typical applications
Test Method
Dimensional verification using CMM or optical comparators, torque testing per ISO 5299, and visual inspection for defects per ASTM D2561

Buyer Feedback

★★★★☆ 4.9 / 5.0 (20 reviews)

"The Keyway we sourced perfectly fits our Rubber and Plastic Product Manufacturing production line requirements."

"Found 12+ suppliers for Keyway on CNFX, but this spec remains the most cost-effective."

"The technical documentation for this Keyway is very thorough, especially regarding technical reliability."

Related Components

Base Deck
Structural foundation component of modular plastic pallets providing load-bearing support and stability.
Interlocking Mechanism
Interlocking mechanism for modular plastic pallets enabling secure stacking and alignment.
Forklift Entry Rails
Structural rails designed to guide forklift entry into modular plastic pallets for safe and precise handling.
Anti-Slip Surface
Anti-slip surface for modular injection molded plastic pallets enhances load stability and workplace safety.

Frequently Asked Questions

Why use a keyway in plastic gears instead of other locking methods?

Keyways provide a cost-effective, standardized, and reliable method for torque transmission in plastic gears, offering easy assembly and disassembly while maintaining alignment. Alternatives like set screws or press fits may cause stress concentrations or damage in polypropylene.

How does polypropylene affect keyway design compared to metal?

Polypropylene has lower strength and higher thermal expansion than metals, requiring keyways to be designed with wider tolerances, rounded corners to reduce stress, and possible reinforcement (e.g., glass fiber) to prevent deformation under load.

What are common failure modes for keyways in plastic gears?

Common failures include cracking due to stress concentration at sharp corners, wear from key movement under cyclic loading, and deformation from excessive torque or thermal expansion mismatches with the shaft.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

Get Quote for Keyway

Interlocking Mechanism Label Holder