INDUSTRY COMPONENT

Carrier Body

The carrier body is the central structural component of a planetary gear system that houses and supports the planet gears.

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Component Specifications

Definition
The carrier body, also known as the planet carrier, is a critical rotating component within a planetary gear set. It serves as the mounting structure for the planet gears (satellite gears), which are evenly spaced and rotate on their own axes while also orbiting around the sun gear. The carrier body's primary functions are to maintain precise alignment and center distance between the planet gears and the sun/ring gears, transmit torque from the planet gears to the output shaft (or vice-versa depending on configuration), and withstand significant radial and axial loads generated during operation. Its design directly influences the gear set's load distribution, efficiency, and noise-vibration-harshness (NVH) characteristics.
Working Principle
The carrier body rotates as a unit with the planet gears. In a typical planetary system, one of the three main elements (sun gear, ring gear, or carrier) is held stationary, another is used as the input, and the third serves as the output. The carrier body's rotation is determined by the motion of the planet gears as they mesh with both the sun gear (at the center) and the ring gear (on the outer perimeter). Its design ensures that all planet gears share the load equally, providing high torque density and compact power transmission.
Materials
Commonly forged or machined from medium-carbon alloy steels such as AISI 4140, 4340, or 8620 for high strength and toughness. For high-performance or weight-sensitive applications, materials may include case-hardened steels (e.g., 20MnCr5), ductile iron (e.g., GGG-40/50), or aluminum alloys (e.g., 7075-T6) with appropriate heat treatment (quenching and tempering, carburizing, or nitriding). Surface hardness typically ranges from 45-60 HRC for steel components to resist wear at gear bearing surfaces.
Technical Parameters
  • Weight 1-50 kg (varies with size and material)
  • Maximum RPM 500-10,000 rpm (depends on balance and lubrication)
  • Bore Diameter 20-200 mm (standard range)
  • Surface Finish Ra 1.6-3.2 μm (critical bearing surfaces)
  • Flange Diameter 50-500 mm
  • Dynamic Load Rating 3-300 kN
  • Static Load Capacity 5-500 kN
  • Dimensional Tolerance IT6-IT7
  • Number of Planet Gears 3, 4, 5, or 6 (most common)
  • Planet Pin Hole Diameter 10-100 mm
Standards
ISO 6336, ISO 1328, DIN 3960, DIN 3961, AGMA 2001, AGMA 6110

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Carrier Body.

carrier body planet carrier planetary gear carrier gearbox component power transmission planetary gear set industrial machinery gear design torque transmission Carrier Body in Machinery and Equipment Manufacturing

Parent Products

This component is used in the following industrial products

Planet Carrier

A structural component in planetary gear systems that holds and supports the planet gears, allowing them to rotate around the sun gear while maintaining proper alignment and spacing.

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Engineering Analysis

Risks & Mitigation
  • Fatigue cracking due to cyclic torsional/bending loads
  • Wear at planet pin bore surfaces leading to misalignment
  • Bearing failure on planet pins causing seizure
  • Imbalance from manufacturing defects or damage inducing vibration
  • Corrosion in harsh environments weakening the structure
FMEA Triads
Trigger: Insufficient material strength or improper heat treatment
Failure: Crack propagation from stress concentrations (e.g., at pin holes)
Mitigation: Use certified alloy steels with Charpy impact testing; apply shot peening to compress surface layers; implement non-destructive testing (NDT) like magnetic particle inspection during manufacturing.
Trigger: Poor lubrication or contaminated lubricant
Failure: Accelerated adhesive wear at planet pin interfaces, leading to increased clearance and impact loads
Mitigation: Specify appropriate EP (extreme pressure) gear oils with filtration systems; design integrated oil passages for direct lubrication; use hardened and ground pins with suitable surface finish.
Trigger: Manufacturing errors in hole position or diameter
Failure: Uneven load distribution among planet gears, causing premature pitting or tooth breakage
Mitigation: Employ CNC machining with tool wear compensation; verify geometry with CMM (Coordinate Measuring Machine) inspection; implement statistical process control (SPC) for critical dimensions.
Trigger: Excessive operating loads beyond design limits
Failure: Plastic deformation or brittle fracture of the carrier arms
Mitigation: Incorporate torque limiters or overload protection in the drive system; conduct finite element analysis (FEA) during design to validate stress levels; define clear operational limits in manuals.

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
Geometric tolerances per ISO 1101:2017; hole position tolerance typically within ±0.02 mm; concentricity of bore to flange within 0.03 mm TIR
Test Method
Dimensional verification via CMM; hardness testing per ISO 6508 (Rockwell); magnetic particle inspection per ASTM E1444 for surface cracks; dynamic balance testing to ISO 1940-1 G2.5 grade; functional testing under load in gearbox assembly

Buyer Feedback

★★★★☆ 4.7 / 5.0 (22 reviews)

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

"Reliable performance in harsh Machinery and Equipment Manufacturing environments. No issues with the Carrier Body so far."

"Testing the Carrier Body now; the technical reliability results are within 1% of the laboratory datasheet."

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Frequently Asked Questions

What is the difference between a carrier body and a planet carrier?

These terms are generally synonymous in industrial contexts. 'Carrier body' often emphasizes the structural housing aspect, while 'planet carrier' refers to the complete assembly including pins/bearings for the planet gears. Both describe the central component that holds the planet gears.

Why are carrier bodies typically made of alloy steel?

Alloy steels like 4140 or 4340 provide an optimal balance of high tensile strength, fatigue resistance, and toughness required to withstand the cyclic bending and torsional stresses in planetary gear systems. They also respond well to heat treatment for enhanced surface hardness and core durability.

How does the number of planet gears affect carrier body design?

More planet gears (e.g., 5 vs. 3) allow higher torque capacity and better load sharing but require a larger, more rigid carrier body with precise hole spacing to maintain equal load distribution. This increases manufacturing complexity and weight.

Can a damaged carrier body be repaired?

Typically not recommended. Critical wear or cracks in the planet pin holes or mounting surfaces compromise structural integrity and precise geometry. Replacement is standard practice to ensure system reliability and prevent catastrophic gear failure.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

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