Gear Box

Gear box in mechanical systems

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Libraries:
Simscape / Foundation Library / Mechanical / Mechanisms

Description

The Gear Box block represents an ideal, nonplanetary, fixed gear ratio gear box. The gear ratio is determined as the ratio of the input shaft angular velocity to that of the output shaft.

The gear box is described with the following equations:

$${\omega }_S=N·{\omega }_O$$

$$T_O=N\cdot T_S$$

$$P_S={\omega }_S\cdot T_S$$

$$P_O=-{\omega }_O\cdot T_O$$

where

• ω_S is input shaft angular velocity.

• ω_O is output shaft angular velocity.

• N is gear ratio.

• T_S is torque on the input shaft.

• T_O is torque on the output shaft.

• P_S is power on the input shaft.

• P_O is power on the output shaft. Notice the minus sign in computing P_O. One of the network rules is that the power flowing through a conserving port is positive if it is removed (dissipated) from the circuit, and is negative if the component generates power into the system.

Connections S and O are mechanical rotational conserving ports associated with the box input and output shaft, respectively. The block positive directions are from S to the reference point and from the reference point to O.

Variables

To set the priority and initial target values for the block variables prior to simulation, use the Initial Targets section in the block dialog box or Property Inspector. For more information, see Set Priority and Initial Target for Block Variables.

Nominal values provide a way to specify the expected magnitude of a variable in a model. Using system scaling based on nominal values increases the simulation robustness. Nominal values can come from different sources, one of which is the Nominal Values section in the block dialog box or Property Inspector. For more information, see Modify Nominal Values for a Block Variable.

Examples

Simple Mechanical System

A model of a system that connects rotational and translational motion. A summing lever drives a load consisting of a mass, viscous friction, and a spring connected to its joint C. Joint B is suspended on two rotational springs connected to reference point through a wheel and axle and a gear box. Joint A is connected to a torque source through a gear box and a wheel and axle mechanism.

• Open Model

Ports

Conserving

S — Input shaft

mechanical rotational

Mechanical rotational conserving port associated with the input shaft.

O — Output shaft

mechanical rotational

Mechanical rotational conserving port associated with the output shaft.

Parameters

Gear ratio — Ratio of gear velocities

5 (default)

The ratio of the input shaft angular velocity to that of the output shaft. You can specify both positive and negative values.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2007a