Model Timing Belt- matching teeth with toothed pulley
Hello, currently I am planning to model a lobe pump (inspired from Netzsch lobe pump), but I have a doubt on modelling timing belt. I have chosen tooted pulley from McMaster Charr, as part numbers are 6495K150, 6495K216 and timing belt- 7891K64. My doubt is how can I design the timing belt that perfectly match with pulley teeth. Now pitch of belt is 9.525 mm. But how to exactly match the pitch circle of pulley to get multiple of 9.525. Is there any way of linking to parameter to change some value thereby getting multiple of it. Also using measure, I couldn't able to select all curve instead it selects a separate sketch, by selecting them separately I can add those length value, but it is bit exhaustive. Do you have any idea to design belt for the above case. I am trying to push my limit and am trying to model with full details.
I would model the timing belt without the teeth. Since CATIA does not have a "pattern along a curve" tool, it would take too much time to show all the teeth along the belt path.
But since you want to push your limits, you could copy the tooth profile from one of the pulleys and use it for the belt teeth. Have fun!
2 Other answers
Q1: "how do I measure multiple sketch (say line combined with circles- profile for belt) in a stretch, when I do so, measure command selects a separate sketch?"
A1: Create a sketch for the belt profile. Project the pitch diameters for each pulley into the sketch. Add the tangent lines and trim the lines & curves to close the profile. Exit the sketch. Join the sketch to create a single curve, and measure the length of the join.
Q2: "How will I able to control the overall profile length to 95.25 mm (as pitch is 9.525 mm)?"
A2: Use the optimizer tool to adjust the length of the belt to a specific size.
Or, you can optimize it manually by adjusting the position of the tensioner pulley:
1. measure the length
2. determine the error by subtracting the desired length from the measured length
3. move the tensioner half the error amount
repeat until the error is small enough