Showing posts with label Gearbox. Show all posts
Showing posts with label Gearbox. Show all posts

Tuesday, November 10, 2015

Pinion Shaft

After discovering that the helical gear in our gearbox was damaged, we also found the PINION SHAFT to be severely damaged as well. This had to match with the helical gear's teeth so the machine shop had to fabricate a new 2" diameter pinion shaft for us. 
The damaged pinion gear
 Total downtime to have both gears fabricated was about three weeks because of the steel hardening process that was involved. This affected production schedules and cost us a lot of money, not including the cost of fabrication. We decided to increase frequency of periodic maintenance shutdowns to avoid major problems like these in the future.

Helical Gear

A few weeks ago, we did something to our Hollow block mould to improve the shape and size of our resulting blocks. This resulted to a heavier mould - my guess would be about 40kgs added from the existing 150 kgs. Unfortunately, the machine's mechanical gear box seemed to experience difficulty in lifting the the entire mould box together with concrete materials (approx 100kgs) inside. It was able to function for about a week, but afterwards, it seemed frequently to stop about half way through lifting. 

Gearbox
Gearbox minus the gears and shafting
We were too lazy to take the machine apart and expose the gearbox. So we first thought about the 3hp induction motor that was driving the gearbox to be the culprit. Hence, we checked its A.C. Contactor and replaced it with a new one. Nope, that didn't work. We finally decided it was the gearbox. 
 
Gear with Shafting
The damaged gear with its shafting (plus someone not wearing safety shoes)

 We took it apart and voila, the 10 inch helical gear was missing a number of its teeth on two different areas of the circumference. We foolishly thought there would be a replacement gear readily available in your leading hardware stores. Surprise surprise, it had to be machined. In the end, we had to have the entire gear fabricated using hardened steel. The old one was made out of casted steel.

Helical Gear
Damaged gear with missing teeth. If it doesn't have teeth, then it sure won't bite!
The machine shop told us to always check for the acceptable loads to avoid future problems with the gearbox. Also check alignments, not to over-tighten the belts, ensure proper lubrication of both gears and bearings. Well, we failed miserably on step number one alone. Lesson learned. But that single gear wasn't the only problem. 

To be continued..