need some advice on gears
Posted by jjtjr
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need some advice on gears September 19, 2020 05:50PM |
My rear end gears failed on my likamobile, trying to figure why they failed. here is photos of them. all the pinion and axles gears are damaged. I can see a tooth broke off and damaged the other gears. the question is why did it break a tooth. Was the gears a poor design to start with or was it metal failure. I will be cutting new ones but need to know why first so it doesn't happen again. Don't know the HRC number or type of alloy used.
From what I been reading on spur gears you should use s45c steel, pressure angle of 20 degs and a HRC # 50 to 60. any help would be good.
From what I been reading on spur gears you should use s45c steel, pressure angle of 20 degs and a HRC # 50 to 60. any help would be good.
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Re: need some advice on gears September 21, 2020 07:56AM |
Tooth failure on a gear is not un heard of but is rare. Most often it’s caused by something ales getting in there. Those gears most likely are off the shelf items in England. Any good gear and bearing shop hear may be able to get then in less then a week.
On my EX the eccentric strap bearing cap came loose and the balls flew out, one landing in the gears between the engine and differential gear. The differential gear being bronze allowed the steal engine gear to drive the hard bearing ball into the bronze gear.
I took a Dremel slitting wheel to cut the ball in half to get it out. The ball did dimple every tooth on the engine gear but the Dremal grinder cleaned up every tooth nicely.
Rolly
On my EX the eccentric strap bearing cap came loose and the balls flew out, one landing in the gears between the engine and differential gear. The differential gear being bronze allowed the steal engine gear to drive the hard bearing ball into the bronze gear.
I took a Dremel slitting wheel to cut the ball in half to get it out. The ball did dimple every tooth on the engine gear but the Dremal grinder cleaned up every tooth nicely.
Rolly
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Re: need some advice on gears November 23, 2020 11:37AM |
Rolly, I need you help on this one, I received new gear. Installed them moved the car 20 feet and it wouldn't move after that.When I installed the new gears there was no binding. They rotated freely. I opened the diff up and this is what I found. the pinion gears had broken teeth. the axle gears were ok. the new gears were cast. I don't see any interference with the axle gears. Is the problem the cast gears being to weak. The other half of the diff looks the same. Could the weight of the car be the problem its 1500 pounds dry.
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Re: need some advice on gears November 25, 2020 06:26AM |
I don't think the involute is correct. The pressure angle appears too low. What was ordered?
I'm going to order the attached gear for outside my differential. It is a 14-1/2 Deg angle. Could you need a 20 degree angle to match your set up? I know that old gears were typically 14-1/2 Deg. That's why I need to go with this gear. Just a thought, I would think that the spider gears would be 20 degrees.
If anyone can help you figure that out, it would be Rolly. Note that the higher the angle, the stronger the tooth. The lower angle puts less load on the bearing.
Sorry I didn't think about this sooner.
Hope this helps,
Rick
I'm going to order the attached gear for outside my differential. It is a 14-1/2 Deg angle. Could you need a 20 degree angle to match your set up? I know that old gears were typically 14-1/2 Deg. That's why I need to go with this gear. Just a thought, I would think that the spider gears would be 20 degrees.
If anyone can help you figure that out, it would be Rolly. Note that the higher the angle, the stronger the tooth. The lower angle puts less load on the bearing.
Sorry I didn't think about this sooner.
Hope this helps,
Rick
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Re: need some advice on gears January 03, 2021 02:36PM |
All four gears are now done.. Heat treating tomorrow. It took 1 day per gear, not having a CNC mill makes it go slow.
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Re: need some advice on gears January 08, 2021 02:09PM |
And i' m not done, yet since I have my machines already setup for gear cutting, just purchased bar stock of 8620 alloy to make another set of gears. This time I will machine it a little different instead of 4 blanks it will be 2 double the length then cut the teeth after that part and face, then to heat treatment for .030 case depth and harden to 50 to 60 HRC.
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