Office Chair Ball Bearing Falling

The falling of ball bearings from an office chair is usually related to the failure of the sealing of the ball bearing or the base turntable structure of the swivel chair, wear and aging, or the expiration of its service life, and can be solved through targeted maintenance.

I. Analysis of the Causes of Ball Bearing Falling

1. Sealing Failure
   • If the ball bearings fall from the connection between the gas spring and the five-star base, it is mostly due to cracks in the oil seal, leading to the failure of the cylinder sealing. After the hydraulic oil leaks, the ball bearings fall off.
   • If the ball bearings come from the base turntable, it may be due to the wear of the bearing cover seal, causing the ball bearings to escape during rotation.
2. Wear or Aging
   • Long-term exposure to friction or a humid, dusty environment can accelerate the failure of the seals inside the bearing, triggering the falling of ball bearings.
   • The fatigue fracture of the brass return spring in the mechanical buckle may also indirectly cause the ball bearings to fall off.
3. Expiration of Service Life
   • After the wear of components such as the bearing or the gas spring, the overall performance declines, making it prone to the falling of ball bearings.

II. Maintenance Methods

1. Maintenance Related to the Gas Spring
   • Check for Leakage: Use a strong flashlight to observe the connection between the gas spring and the five-star base. If there are traces of black, viscous hydraulic oil leakage, the gas spring needs to be replaced.
   • Replace the Return Spring: If the small ball bearing rebound button on the outside of the five-star base is loose, it may be due to the fracture of the brass return spring. A 2.5mm nickel-plated steel replacement part needs to be installed, and the pre-pressure of the top buckle should be adjusted to 2 Newtons.
2. Maintenance of the Base Turntable
   • Replenish Ball Bearings: Disassemble the base turntable (a cross or hexagonal screwdriver is required), clean the oil and dust in the card slots; evenly place new ball bearings of the same specification into the card slots, apply grease, use a special tool to push the ball bearings into the appropriate positions, and install a new bearing seal cover.
   • Replace the Turntable Assembly: If the card slots are severely worn or there are too many missing ball bearings, a matching new turntable (preferably made of thickened cold-rolled steel plate with a full-ball bearing structure) needs to be purchased. Align it with the screw holes at the bottom of the chair and re-fix it with the original screws.
3. Temporary Repair Solution
   • If waiting for the new gas spring to arrive, a 0.5mm graphite lubricating sheet can be cut into strips of 10×30mm and wound around the threaded base of the gas spring twice to form a physical wedge-shaped sealing strip, providing a buffer period of about 40 days.

III. Precautions

1. Safe Operation: When disassembling safety components, use a torque-limiting wrench to loosen the bolts. Do not use an impact electric wrench to damage the pneumatic threaded joints.
2. Daily Maintenance: Rotate and lift the chair to trigger three complete strokes every week to keep the O-shaped silicone ring actively sliding; apply organic silicon protective grease to the exposed part of the aluminum alloy piston rod every quarter to isolate moisture; regularly clean the bearing and replace aging seals to prevent foreign objects from entering.
3. Immediate Disuse: If the chair continuously descends by more than 4cm, it should be immediately disused to avoid the risk of cylinder explosion.