Four-point contact ball bearings
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Four‑Point Angular Contact Ball Bearings – The Ideal Choice for Humanoid Robot Joints
Precisely Meeting the Bearing Demands of Humanoid Robots
Humanoid robot joints demand bearings that are exceptionally low‑friction for smooth motion, compact for tight layouts, and lightweight to minimize energy consumption. Traditional deep‑groove ball bearings lack sufficient load capacity and rigidity, while crossed roller bearings offer high rigidity at the cost of complex installation and high expense.
Our Four‑Point Angular Contact Ball Bearings, specifically developed for humanoid robotics, deliver a comprehensive performance breakthrough—making them the ideal replacement for both conventional options.
Core Product Advantages
1. Higher Load Capacity in the Same Footprint – Dramatically Extended Life
With a special raceway profile design combined with superior superfinishing technology, our bearings achieve lightweight and compact construction while providing the performance characteristics of double‑row angular contact ball bearings. External dimensions are identical to standard deep‑groove ball bearings, enabling direct drop‑in replacement without any design changes.
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Load capacity: Approximately 1.5 times that of same‑size deep‑groove ball bearings
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Calculated service life: Approximately 3.5 times that of same‑size deep‑groove ball bearings
This translates into substantially higher torque output within the same housing envelope, along with dramatically extended operational life.
2. Minimal Axial Clearance – Exceptional Rigidity
The axial clearance is only 1/5 that of deep‑groove ball bearings, delivering remarkable rigidity. The bearings excel particularly in axial stiffness and bending moment stiffness—critical for humanoid robot joints that endure complex compound loads, effectively suppressing vibration and ensuring motion precision.
3. Low‑Friction Design – Faster Response
Optimized raceway geometry and superior surface finish significantly reduce running torque. Robot joints respond more swiftly, motion becomes smoother, and energy losses are minimized—enhancing overall system efficiency and extending battery life.
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Comparison Deep‑Groove Ball Bearing Crossed Roller Bearing Four‑Point Angular Contact Ball Bearing Load Capacity Baseline High 1.5× of deep‑groove Service Life Baseline Higher 3.5× of deep‑groove Rigidity Moderate Extremely High High (1/5 axial clearance) Installation Simple Complex (precision adjustment) Simple (like deep‑groove) Cost Low High Moderate – lower total cost -
The Ideal Replacement Solution
Our Four‑Point Angular Contact Ball Bearings can replace both conventional deep‑groove ball bearings and crossed roller bearings, delivering significant comprehensive benefits:
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Replacing deep‑groove ball bearings → Longer life, higher rigidity, greater load capacity
Replacing crossed roller bearings → Simpler installation, lower cost, more compactFull‑Scenario Application Coverage
This series covers all critical joints of humanoid robots:
Application Operating Characteristics Bearing Value Linear actuators Combined tensile/compressive and bending loads High rigidity ensures positioning accuracy Rotary actuators High‑frequency reciprocating rotation Low friction ensures smooth motion Ankle joints Multi‑directional swing + impact loads High rigidity suppresses lateral wobble Waist joints Large overturning moment + full body weight High bending rigidity ensures posture stability Leg joints High‑dynamic walking/jumping impacts Extended life supports high‑load cycles Customer Value Summary
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Upgrade without redesign: Identical external dimensions to deep‑groove ball bearings – no housing modifications needed
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Multiplied performance: 1.5× load capacity + 3.5× service life + 5× rigidity (axial clearance only 1/5)
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One bearing, multiple roles: Combines the convenience of deep‑groove bearings with the high rigidity of crossed roller bearings – at lower overall cost
In one sentence: Make your robot joints stronger, stiffer, and more durable at a lower total cost—without changing a single design detail.
Contact us for detailed technical specifications and sample testing support.
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Thin Section Ball Bearings Dimension Chart

| Outer Dia D (mm) | Outer Dia D (inch) | Radius rs(min) (mm) | Width B (mm) | Width B (inch) | Open Model | Shield Model | Seal Type |
| 15 | 0.5906 | 0.15 | 3 | 0.1181 | 6700 | - | TTS |
| 19 | 0.748 | 0.3 | 4 | 0.1575 | 6800 | 6700ZZS | 2RS |
| 19 | 0.748 | 0.3 | 4 | 0.1575 | 6800 | 6800ZZ | 2RU |
| 19 | 0.748 | 0.3 | 7 | 0.2756 | 63800 | 63800ZZ | 2RS |
| 22 | 0.8661 | 0.3 | 7 | 0.2756 | 6900 | 6900ZZ | 2RU |
| 18 | 0.7087 | 0.2 | 4 | 0.1575 | 6701 | 6701ZZS | TTS |
| 20 | 0.7827 | 0.3 | 5 | 0.1969 | 6801 | 6801ZZ | 2RS |
| 20 | 0.7827 | 0.3 | 5 | 0.1969 | 6801 | 6801ZZ | 2RU |
| 24 | 0.9449 | 0.3 | 7 | 0.2756 | 6901 | 6901ZZ | 2RU |
| 21 | 0.8268 | 0.2 | 4 | 0.1575 | 6702 | 6702ZZS | TTS |
| 24 | 0.9449 | 0.3 | 5 | 0.1969 | 6802 | 6802ZZ | 2RS |
| 24 | 0.9449 | 0.3 | 5 | 0.1969 | 6802 | 6802ZZ | 2RU |
| 28 | 1.1024 | 0.3 | 7 | 0.2756 | 6902 | 6902ZZ | 2RU |
| 23 | 0.9055 | 0.2 | 4 | 0.1575 | 6703 | 6703ZZS | TTS |
| 26 | 1.0236 | 0.3 | 5 | 0.1969 | 6803 | 6803ZZ | 2RS |
| 26 | 1.0236 | 0.3 | 5 | 0.1969 | 6803 | 6803ZZ | 2RU |
| 30 | 1.1811 | 0.3 | 7 | 0.2756 | 6903 | 6903ZZ | 2RU |
| 27 | 1.063 | 0.2 | 4 | 0.1575 | 6704 | 6704ZZS | TTS |
| 32 | 1.2598 | 0.3 | 7 | 0.2756 | 6804 | 6804ZZ | 2RS |
| 32 | 1.2598 | 0.3 | 7 | 0.2756 | 6804 | 6804ZZ | 2RU |
| 37 | 1.4567 | 0.3 | 10 | 0.3937 | 6904 | 6904ZZ | 2RU |
| 32 | 1.2598 | 0.2 | 4 | 0.1575 | 6705 | - | - |
| 37 | 1.4567 | 0.3 | 7 | 0.2756 | 6805 | 6805ZZ | 2RS |
| 37 | 1.4567 | 0.3 | 7 | 0.2756 | 6805 | 6805ZZ | 2RU |
| 42 | 1.6535 | 0.3 | 10 | 0.3937 | 6905 | 6905ZZ | 2RU |
| 37 | 1.4567 | 0.2 | 4 | 0.1575 | 6706 | - | - |
| 42 | 1.6535 | 0.3 | 7 | 0.2756 | 6806 | 6806ZZ | 2RS |
| 42 | 1.6535 | 0.3 | 7 | 0.2756 | 6806 | 6806ZZ | 2RU |
| 47 | 1.8504 | 0.3 | 10 | 0.3937 | 6906 | 6906ZZ | 2RU |
| Bore Dia d (mm) | Bore Dia d (inch) | Outer Dia D (mm) | Outer Dia D (inch) | Radius rs(min) (mm) | Width B (mm) | Width B (inch) | Open Model | Shield Model | Seal Type |
| 35 | 1.378 | 47 | 1.8504 | 0.3 | 5 | 0.1969 | 6707 | 6707ZZ | 2RS |
| 35 | 1.378 | 47 | 1.8504 | 0.3 | 5 | 0.1969 | 6707 | 6707ZZ | 2RU |
| 35 | 1.378 | 55 | 2.1654 | 0.6 | 7 | 0.2756 | 6907 | 6907ZZ | 2RU |
| 40 | 1.5748 | 50 | 1.9685 | 0.3 | 6 | 0.2362 | 6708 | 6808ZZ | 2RS |
| 40 | 1.5748 | 52 | 2.0472 | 0.3 | 7 | 0.2756 | 6808 | 6808ZZ | 2RS |
| 40 | 1.5748 | 62 | 2.4409 | 0.6 | 12 | 0.4724 | 6908 | 6908ZZ | 2RU |
| 45 | 1.7717 | 55 | 2.1654 | 0.3 | 6 | 0.2362 | 6709 | 6809ZZ | 2RS |
| 45 | 1.7717 | 58 | 2.2835 | 0.3 | 7 | 0.2756 | 6809 | 6809ZZ | 2RS |
| 45 | 1.7717 | 68 | 2.6772 | 0.6 | 12 | 0.4724 | 6909 | 6909ZZ | 2RU |
| 50 | 1.9685 | 62 | 2.4409 | 0.3 | 6 | 0.2362 | 6710 | - | 2RS |
| 50 | 1.9685 | 65 | 2.5591 | 0.3 | 7 | 0.2756 | 6810 | 6810ZZ | 2RS |
| 50 | 1.9685 | 72 | 2.8346 | 0.6 | 12 | 0.4724 | 6910 | 6910ZZ | 2RU |
| 55 | 2.1654 | 72 | 2.8346 | 0.3 | 9 | 0.3543 | 6811 | 6811ZZ | 2RS |
| 55 | 2.1654 | 80 | 3.1496 | 1 | 13 | 0.5118 | 6911 | 6911ZZ | 2RS |
| 60 | 2.3622 | 78 | 3.0709 | 0.3 | 10 | 0.3937 | 6812 | 6812ZZ | 2RS |
| 60 | 2.3622 | 85 | 3.3465 | 1 | 13 | 0.5118 | 6912 | 6912ZZ | 2RS |
| 65 | 2.5591 | 85 | 3.3465 | 0.6 | 10 | 0.3937 | 6813 | 6813ZZ | 2RS |
| 65 | 2.5591 | 90 | 3.5433 | 1 | 13 | 0.5118 | 6913 | 6913ZZ | 2RS |
| 70 | 2.7559 | 90 | 3.5433 | 0.6 | 10 | 0.3937 | 6814 | 6814ZZ | 2RS |
| 70 | 2.7559 | 100 | 3.937 | 1 | 16 | 0.6299 | 6914 | 6914ZZ | 2RS |
| 75 | 2.9528 | 95 | 3.7402 | 0.6 | 10 | 0.3937 | 6815 | 6815ZZ | 2RS |
| 75 | 2.9528 | 105 | 4.1339 | 1 | 16 | 0.6299 | 6915 | 6915ZZ | 2RS |
| 80 | 3.1496 | 100 | 3.937 | 0.6 | 10 | 0.3937 | 6816 | 6816ZZ | 2RS |
| 80 | 3.1496 | 110 | 4.3307 | 1 | 16 | 0.6299 | 6916 | 6916ZZ | 2RS |
| 85 | 3.3465 | 110 | 4.3307 | 1 | 13 | 0.5118 | 6817 | 6817ZZ | 2RS |
| 85 | 3.3465 | 120 | 4.7244 | 1.1 | 18 | 0.7087 | 6917 | 6917ZZ | 2RS |
| 90 | 3.5433 | 115 | 4.5276 | 1 | 13 | 0.5118 | 6818 | 6818ZZ | 2RS |
| 90 | 3.5433 | 125 | 4.9213 | 1.1 | 18 | 0.7087 | 6918 | 6918ZZ | 2RS |
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