Engee documentation

Wheel and Axle

Wheel and axle.

blockType: AcausalFoundation.Mechanical.Mechanisms.WheelAndAxle

wheel and axle

Path in the library:

/Physical Modeling/Fundamental/Mechanical/Mechanisms/Wheel and Axle

Description

Block Wheel and Axle It is a wheel and axle mechanism shown in the following diagram.

wheel and axle 1

The wheel and the axle are coaxial, and it is assumed that the axle is rigidly connected to the frame, which makes this mechanism an ideal converter of mechanical rotational motion into mechanical translational motion. The mechanism has two connections: a mechanical rotary port A corresponding to the axis, and a mechanical translational port P corresponding to a point on the wheel rim. The mechanism is described by the following equations:



where

  • Т — the torque on the axis;

  • — force on the wheel rim;

  • — angular velocity of the wheel;

  • — linear speed on the wheel rim;

  • — wheel radius;

  • — orientation of the mechanism. The value is +1 if the rotation of the axis in a globally defined positive direction is transformed into translational motion in the positive direction, and −1 if a positive rotation leads to a translational motion in a negative direction.

Use this unit when modeling rack and pinion gears, steering wheels, hoists, winches, etc.

The positive directions of the block are from A to the reference point and from the reference point to P.

Variables

Use the parameter group Initial Targets to set the priority and initial target values for the block parameter variables before modeling. For more information, see Configuring physical blocks using target values.

Ports

Conserving

# A — axis
rotational mechanics

Details

Mechanical rotary port, corresponds to the axis.

Program usage name

axle_flange

# P — periphery of the wheel
translational mechanics

Details

Mechanical translational port, corresponds to a point on the rim of the wheel.

Program usage name

translational_flange

Parameters

Parameters

# Wheel radius — wheel radius
m | um | mm | cm | km | in | ft | yd | mi | nmi

Details

The radius of the wheel.

Units

m | um | mm | cm | km | in | ft | yd | mi | nmi
Default value

0.05 m
Program usage name

R
Evaluatable

Yes

# Mechanism orientation — the relationship between the rotation of the axis and the direction of translational motion
Drives in positive direction | Drives in negative direction

Details

Meaning Drives in positive direction This means that the rotation of the axis in the globally assigned positive direction is converted into translational motion in the positive direction. Meaning Drives in negative direction This means that the rotation of the axis in the globally assigned positive direction is converted into translational motion in the negative direction.

Values

Drives in positive direction | Drives in negative direction
Default value

Drives in positive direction
Program usage name

orientation
Evaluatable

No

Examples