Apply load and speed ratios first: record radial force in kN, rotational rate in rpm, plus operating heat range. Use these values to select grease or oil grade through viscosity charts tied to DN or n·dm factors, keeping film thickness above mixed-contact limits.
Control volume with geometry rules: fill 20–30% of free cavity for high-speed units, raise toward 40% for slow rotation or shock load. Overfill increases drag and heat rise; underfill shortens service life through metal contact.
Schedule replenishment using duty hours, contamination class, and seal type. Clean environments allow intervals up to 5,000 hours; dusty zones cut this by half. Log temperature drift above baseline as trigger for earlier service.
Determining grease or oil quantity from unit size and load
Apply cavity fill rules tied to housing volume: use 20–30% fill for high rotational rates above 3,000 rpm, shift toward 35–40% for speeds below 500 rpm or heavy radial force above 0.15 C. Measure free space in cubic centimeters, then multiply by chosen fill ratio to set charge mass.
Adjust amount using load class: light duty below 0.05 C keeps base volume unchanged, medium duty adds 10%, shock duty above 0.2 C adds 15–20% while limiting speed to avoid heat rise. Axial load presence pushes selection toward oil bath with level set at mid-rolling element height.
Verify choice through temperature trend after run-in: steady-state increase under 15°C from ambient signals correct volume, 20–30°C rise signals excess, rapid climb with noise signals shortage. Record values for repeat service cycles.
Selecting lubricant viscosity using speed factor and operating temperature
Match kinematic grade to speed factor: compute DN value by multiplying shaft rate by pitch diameter in millimeters. DN below 150,000 pairs with ISO VG 150–220, mid-range 150,000–300,000 aligns with VG 68–100, values above 300,000 call for VG 32–46 to limit churning and drag.
Correct grade through heat conditions: target operating viscosity at contact zone between 12 and 20 cSt. For sump heat near 80 °C, raise nominal grade one step; for steady range below 40 °C, lower grade one step to secure flow at start-up.
Confirm choice using run data: stable noise profile and surface heat rise under 15 °C from baseline signal proper film. Whine with rapid temperature climb points to excess thickness; discoloration or vibration under load signals insufficient film strength.
Setting relubrication intervals based on duty cycle and contamination level
Base timing on operating hours and speed: continuous rotation above 2,000 rpm calls for replenishment every 1,000–2,000 hours; intermittent duty under 8 hours per day extends window to 3,000–5,000 hours. Shock loading trims interval by 30% due to accelerated film breakdown.
Adjust schedule through contamination class: clean, sealed housings allow full interval use; light dust exposure halves timing; heavy particulate or moisture presence cuts cycle to one quarter. Open arrangements near washdown zones require visual checks every 250 hours.
Validate interval via condition signals: steady heat profile and stable vibration confirm timing, while rising temperature, darkened grease, or abrasive noise demand earlier service. Log findings to refine future service periods.
