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Gear Ratio Calculator (i=z₂/z₁)

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Compute the gear ratio via i = z₂/z₁: enter driving/driven tooth counts and input speed to get ratio, output speed and torque multiplication.

Key points

Gear Ratio Calculator (i=z₂/z₁): Compute the gear ratio via i = z₂/z₁: enter driving/driven tooth counts and input speed to get ratio, output speed and torque multiplication. Formula: i = z₂/z₁ = n₁/n₂ = τ₂/τ₁. Enter parameters on the DD-CAT IDE online tool page to get results instantly, with a calculation-model diagram that updates with the inputs. i = z₂/z₁ = n₁/n₂: the tooth-count ratio sets the gear ratio; i > 1 reduces speed and increases torque, i < 1 increases speed and reduces torque. Speed and torque: n₂ = n₁/i, τ₂ = τ₁·i (ideal, lossless); real output torque must be multiplied by transmission efficiency η (0.9–0.98).

Inputs

i = z₂/z₁ = n₁/n₂ = τ₂/τ₁

Calculation model (updates with parameters)

z₁=20主动z₂=60从动i = 3 | n₂ = 500 rpm
Gear ratio i3
Output speed n₂500rpm
Output torque τ₂150N·m
Rotation directionSame (external single-stage meshing reverses)

Engineering notes

  • i = z₂/z₁ = n₁/n₂: the tooth-count ratio sets the gear ratio; i > 1 reduces speed and increases torque, i < 1 increases speed and reduces torque.
  • Speed and torque: n₂ = n₁/i, τ₂ = τ₁·i (ideal, lossless); real output torque must be multiplied by transmission efficiency η (0.9–0.98).
  • The total ratio of multi-stage gearing is the product of the stages; each external mesh reverses direction, while idlers change direction without altering the ratio.

FAQ

What is Gear Ratio Calculator (i=z₂/z₁) for?
Compute the gear ratio via i = z₂/z₁: enter driving/driven tooth counts and input speed to get ratio, output speed and torque multiplication.
What is the formula for Gear Ratio Calculator (i=z₂/z₁)?
Core formula: i = z₂/z₁ = n₁/n₂ = τ₂/τ₁. The tool returns results instantly using this formula and the selected parameters.
What engineering notes should I keep in mind when using Gear Ratio Calculator (i=z₂/z₁)?
i = z₂/z₁ = n₁/n₂: the tooth-count ratio sets the gear ratio; i > 1 reduces speed and increases torque, i < 1 increases speed and reduces torque. Speed and torque: n₂ = n₁/i, τ₂ = τ₁·i (ideal, lossless); real output torque must be multiplied by transmission efficiency η (0.9–0.98). The total ratio of multi-stage gearing is the product of the stages; each external mesh reverses direction, while idlers change direction without altering the ratio.