Register to reply

Pitch Circle

by Jones1987
Tags: circle, pitch
Share this thread:
Jones1987
#1
Nov3-10, 05:45 AM
P: 79
http://82.165.2.248/mechanisms/pages...ciprocate.html

How would I work out the pitch circle and number of teeth required to move the mechanism a certain amplitude? Looked over 4-5 sources for pitch circle, but cannot make sense of it..
Phys.Org News Partner Science news on Phys.org
Experts defend operational earthquake forecasting, counter critiques
EU urged to convert TV frequencies to mobile broadband
Sierra Nevada freshwater runoff could drop 26 percent by 2100
tvavanasd
#2
Nov4-10, 11:21 PM
P: 88
In the animation, if the pinion had all its teeth, there would be 12. 7 of those teeth have been removed (5 remaining). Not absolutely sure, but based on the model, it may only work with an even number of pinion teeth (prior to removal). 1 more than half of the original number of teeth likely have to be removed.
The rack shifts a total (from left to right say, before returning) of:
(pitch diameter) x (pi) / 2
or
(rack tooth pitch) x (number of original pinion teeth) / 2

This mechanism is really not very nice. Although it appears to be simple, its motion is quite violent. At the end of each stroke there is infinite acceleration. In the animation, it looks smooth, but that's only because the rack has no mass.
Jones1987
#3
Nov7-10, 02:24 PM
P: 79
Quote Quote by tvavanasd View Post
In the animation, if the pinion had all its teeth, there would be 12. 7 of those teeth have been removed (5 remaining). Not absolutely sure, but based on the model, it may only work with an even number of pinion teeth (prior to removal). 1 more than half of the original number of teeth likely have to be removed.
The rack shifts a total (from left to right say, before returning) of:
(pitch diameter) x (pi) / 2
or
(rack tooth pitch) x (number of original pinion teeth) / 2

This mechanism is really not very nice. Although it appears to be simple, its motion is quite violent. At the end of each stroke there is infinite acceleration. In the animation, it looks smooth, but that's only because the rack has no mass.
So if I had a pitch diameter of (0.1m) x (pi) / 2 = 0.1571 m/s? Is this correct?

tvavanasd
#4
Nov7-10, 08:19 PM
P: 88
Pitch Circle

Quote Quote by Jones1987 View Post
So if I had a pitch diameter of (0.1m) x (pi) / 2 = 0.1571 m/s? Is this correct?
I expect that travel should be 0.157 m.
Why are you suggesting the answer is in m/s?
Jones1987
#5
Nov8-10, 06:42 AM
P: 79
So does it mean the pitch circle is 0.157m or the distance the rack moves is 0.157m per revolution?


Register to reply

Related Discussions
Equation of circle in quarter/half of a circle Precalculus Mathematics Homework 2
How will the air temperature in the room affect the pitch of organ General Physics 0
Simple circle circle collision detection General Math 6
Why are pitch and frequency similiar to loudness and intensity? General Physics 3
Musical question regarding concert pitch/philosophical pitch Introductory Physics Homework 4