How to Adjust Bevel Gears


How to Adjust Bevel Gears

Adjusting bevel gears is critical to ensuring their proper and trouble-free operation. This process involves aligning the gears correctly, setting appropriate clearances, and achieving correct contact patterns. Here is a step-by-step guide on how to adjust bevel gears:

1. Prepare the Gearbox

Cleaning : Thoroughly clean the inside of the gearbox. Ensure all components are free of dirt, oil, and metal shavings.
Visual Inspection: Inspect the gears and bearings for signs of wear, damage, or cracks.

2. Install Gears and Bearings

Bearing Installation : Carefully place the bearings that support the bevel gears. Ensure the bearings are properly seated and aligned.
Gear Installation : Mount the bevel gear on the shaft and position it on the bearings. Ensure the gear rotates freely without any binding.

3. Pre-Adjustment

Backlash Adjustment : There should be a specific clearance (backlash) between the gears to allow them to rotate freely and expand as they heat up. Use the adjustment screws to set this clearance.
Hold the gears stationary with one hand while checking for slight movement with the other. There should be a minimal gap between the gears.

4. Contact Pattern Adjustment

Marking : Apply gear marking compound or a suitable indicator to the gear's contact surfaces. This helps in checking the contact pattern.
  Rotate the gears several times and then inspect the contact surfaces. You should see an even and full contact pattern on the gear surfaces. The contact should be centered and spread across the entire width of the teeth.

5. Fine Adjustment

Backlash and Contact Pattern : Fine-tune the backlash and contact pattern adjustments. Make small adjustments to the screws to achieve the desired clearance and contact pattern.
Bearing Preload : Ensure the bearings have the appropriate preload. They should not be too tight or too loose. You can check the preload by moving the shaft back and forth.

6. Final Checks and Tests

Rotation Check : Manually rotate the gears to check for any abnormal noises, binding, or resistance.
Lubrication : Lubricate the gears with appropriate gear oil. Proper lubrication extends the life of the gears and reduces friction.
Test Run : Run the gearbox at a low speed to verify all adjustments are correct. If any abnormalities are detected, recheck the adjustments.
Bevel gear adjustments require precise handling and if not done correctly, can shorten the gear's lifespan or cause failures. Therefore, it's crucial to perform these adjustments carefully and seek expert assistance if necessary.