Rack and Pinion Gear

If Simplified method is selected, the following options will be displayed:

Module (Normal plane)

Enter a value for the module expressed in the normal plane.

Module (Normal) = Pitch (Normal) / π

Here, the Pitch is the distance from one point on a tooth to the same point on the next tooth (measured in the normal plane).

Pressure Angle (Normal plane)

Enter a nominal pressure angle in current modelling Units (default value = 20.0 deg) expressed in the normal plane. For the rack gear this angle is the angle between a vertical line and the tooth profile at the datum line.

Helix Angle

Enter a value for the helix angle (beta) in current modelling Units. The helix angle describes how the teeth are angled from the transversal plane.

Name

Enter the name of the Rack/Pinion.

Axis of Rotation/Translation

Axis of Rotation of pinion and Axis of Translation of rack can be one of the following:

Center Location

Enter the coordinates or Pick (Markers, View location and so on.)

No. of Teeth

Enter the number of teeth for Rack and Pinion. The number of teeth is always an integer > 0.

Face Width

Enter the width for Rack and Pinion in modelling units.

Bore Radius

Enter the radius for the hole in the pinion gear (only used for graphics).

Hand of Helix

Base Thickness

Enter the thickness of the base of the rack in modeling units (geometry only). The base thickness is measured from the root to the bottom of the gear part. Default value = 5mm.

Root Fillet Radius Coeff.

Enter a coefficient > 0 to be multiplied with the module. The resulting product will describe the root filet radius for rack. If the value is 0 no radius will be used.

Geometry Settings

If 3D Contact method is selected, the following options will be displayed:

Module (Normal)

The module is the pitch diameter divided by the number of teeth.

Pressure Angle (Normal)

Enter a nominal pressure angle in current modelling Units (default value = 20.0 deg) expressed in the normal plane. For the rack gear this angle is the angle between a vertical line and the tooth profile at the datum line.

Helix Angle

Enter a value for the helix angle (beta) in current modelling Units. The helix angle describes how the teeth are angled from the transversal plane.

Name

Enter the name for the Rack/Pinion.

Axis of Rotation/Axis of Translation

Axis of Rotation of pinion and Axis of Translation of rack can be one of the following:

Center Location

Enter the coordinates or Pick (Markers, View location and so on.)

No. of Teeth

Enter the number of teeth for Rack and Pinion.

Face Width

Enter the face width for Rack and Pinion in modelling units.

Hand of Helix

Base Thickness

Enter the thickness of the base of the rack in modeling units (geometry only). The base thickness is measured from the root to the bottom of the gear part. Default value = 5mm.

Bore Radius

Enter the radius for the hole in the pinion gear (only used for graphics).

Profile

Select how the involute profile should be described using the Standard Involute Profile parameters (Profile Shifting, Addendum Factor & Dedendum Factor) or if the parameters for the Modified Involute Profile (Tip Radius, Root Radius & Tooth Thickness) should be used.

If Standard profile is selected, the following options will be displayed:

Profile Shift Coeff.

Enter a value for profile shift coefficient (Previously called addendum modification coefficient) for the gear (positive or negative value). The value decides if the datum line is to be shifted towards the top (positive) or towards the root (negative value). Default value = 0.0. If this field is left blank, no profile shifting will be used.

Addendum Factor

Enter a value for the Addendum Factor (default value = 1.0). The Addendum Factor is used to calculate the Addendum:

Addendum (Normal) = Module (Normal) * Addendum Factor

Dedendum Factor

Enter a value for the Dedendum Factor (default value = 1.25). The Dedendum Factor is used to calculate the Dedendum:

Dedendum (Normal) = Module (Normal) * Dedendum Factor

Root Fillet Radius Coeff.

Enter a coefficient > 0 to be multiplied with the module. The resulting product will describe the root filet radius for rack. If the value is 0 no radius will be used.

If Modified profile is selected, the following options will be displayed:

Pinion Parameters

Tooth Thick

Enter a value for the tooth thickness at the pitch circle. Must be less than 10 times the value of module. For module = 2, tooth thickness needs to be <20, not 0.2.

Tip Radius

The addendum circle, or outside circle, is the circle that contains the tips of the teeth, and its radius is the outside radius (tip radius). In the database navigator this will appear as 'tip_rad'.

Root Radius

The dedendum circle, or root circle, is the circle that contains the ends of the tooth spaces, and its radius is the root radius (foot radius). In the database navigator this will appear as 'foot_rad'.

Rack Parameters

Tooth Height

Enter a value > 0 in length units for the Tooth Height for the rack gear. The Tooth Height is measured from the root (bottom) of the tooth profile to the tip of a tooth (top).

Pitch Line Offset

Enter a value > 0 in length units for the offset from the tip or a tooth (top of the rack) to the Pitch line.

Tooth Thickness (along pitch line)

Enter a value > 0 in length units for the thickness of the teeth measured in the transversal plane at the pitch line.

Root Fillet Radius

Enter a value ≥ 0 to define the root filet radius. If the value is 0 no radius will be used.

Tooth Modification Parameters for Rack and Pinions

Tip Relief Start

Tip relief is a modification of a tooth profile whereby a small amount of material is removed near the tip of the gear tooth.

The Tip Relief Start parameter defines the position on the tooth at which the Tip Relief will start. The resulting starting radius on the gear will be:

The Module (Transverse), MT is defined as below:

If the gear is defined by Standard Involute Profile, the Tip Radius is defined as below:

Tip Relief Coefficient

This coefficient defines the maximum Tip Relief reached at the Tip Radius of the gear. The Tip Relief is defined by:

The tip relief will have zero value at the Tip Relief Start point and increase linearly out to the Tip Radius.

Crown Magnitude

Crowning is the removal of a slight amount of tooth from the center on out to reach edge, making the tooth surface slightly convex. This method allows the gear to maintain contact in the central region of the tooth and permits avoidance of edge contact with consequent lower load capacity. Crowning also allows a greater tolerance in the misalignment of gears in their assembly, maintaining central contact.

The crown magnitude is reached at the edges of the tooth and crowning is zero at the center of the tooth. The crowning is described as an arc.

The Crown Magnitude is entered in length units.

Geometry Settings