Program Tooth Thickness/Space Width & Pressure Angle at Shifted Diameter

Transcription

1 Program Tooth Thickness/Space Width & Pressure Angle at Shifted Diameter Introduction The purpose of this model is to enable you to find the tooth thickness (or space width for internal gears), the pressure angles, roll angles and the helix angle at any diameter above the base diameter if you know these values at any other diameter. Example As an example of how we might make use of this model we will obtain some useful information for a helical gear with the following specifications: 19 teeth 10 Normal Diametral Pitch 20 Normal Pressure Angle inch Normal Tooth Thickness at Ref PD of 19/(10*Cos(23)) = We may want the tooth thickness at the outside diameter. Figure 1 shows the wizard data input form with the required data entered. The OD of inches is the Check Diameter and the Ref PD is the Reference Diameter. Fig. 1

2 UTS Integrated Gear Software Report 1 is the solved model. The normal tooth thickness at the OD is.0696 inch. The helix angle, roll angle and the pressure angles are also shown. Report 1 Model Title : Program Unit System: US Description Value Unit Comment At Reference Diameter Reference Diameter Normal Pressure Angle Trans Pressure Angle Roll Angle Lead At Check Diameter Check Diameter Normal Pressure Angle Trans Pressure Angle Roll Angle in deg deg deg deg deg in in in in in deg deg deg deg deg 2

3 Tooth Thickness/Space Width & Pressure Angle at Shifted Diameter Model Title : Program Unit System: US Description Value Unit Comment At Base Diameter in in in Base Diameter in deg deg in in in A plot of the tooth between the base diameter and the larger of the reference or check diameters is available. Figure 2 is the transverse plane tooth plot for Report 1. Figure 3 is the axial plane tooth plot for Report 1. 3

4 UTS Integrated Gear Software Fig. 2 Fig. 3 4

5 Tooth Thickness/Space Width & Pressure Angle at Shifted Diameter If we wish to find the diameter where the teeth would become pointed all that is necessary is to enter zero in the input column for the tooth thickness and change the Check Diameter to a guess value. A satisfactory guess would be the OD, (Enter this value in the TK Solver Variable Sheet for the Check Diameter, then double-click the Status cell for this variable and pick Guess from the drop-down list, as shown in Sheet 1A.) A guess is necessary, as the equations cannot be solved directly in this direction. Sheet 1B shows that the teeth would be pointed at a diameter of inches. Sheet 1A 5

6 UTS Integrated Gear Software Sheet 1B Suppose we are using a short lead hob to cut the gear with a hob flank angle of 14.5 degrees. We may wish to know the generating diameter, the transverse pressure angle and the tooth thickness there. Enter 14.5 for the normal pressure angle at the check diameter and make a guess of about 2 for the check diameter. (Enter 2 for an input value, then make it a Guess value as you did in the Sheet 1 example.) Sheet 2A shows the data entry and Sheet 2B the solution for this data. 6

7 Tooth Thickness/Space Width & Pressure Angle at Shifted Diameter Sheet 2A 7

8 UTS Integrated Gear Software Sheet 2B The generating diameter is inches, the transverse pressure angle is degrees, and the normal tooth thickness is.1724 inch. If we wish to use different units for input or output, we need only to change the units using the Toolbar radio button. Report 2 shows the solved model after changing metric units. 8

9 Tooth Thickness/Space Width & Pressure Angle at Shifted Diameter Report 2 Model Title : Program Unit System: Metric Description Value Unit Comment At Reference Diameter Reference Diameter Normal Pressure Angle Trans Pressure Angle Roll Angle Lead At Check Diameter Check Diameter Normal Pressure Angle Trans Pressure Angle Roll Angle mm deg deg deg deg deg mm mm mm mm mm deg deg deg deg deg mm mm 9

10 UTS Integrated Gear Software Model Title : Program Unit System: Metric Description Value Unit Comment At Base Diameter mm Base Diameter mm deg deg mm mm mm The space width for internal gears may be input instead of tooth thickness to find the space width at various diameters. 10