Two-way Load Bearings for Axial Use

Product Overview

Two-way Load Bearings for Axial Use (also known as double-direction axial bearings) are specialized components engineered to support axial loads from both directions— a critical function in machinery where shafts experience thrust forces forward and backward (e.g., machine tool spindles or hydraulic cylinders). Unlike one-way axial bearings, which only handle load in a single direction, these bearings eliminate the need for paired one-way bearings, reducing installation space by up to 35% and simplifying mechanical design. They feature a compact structure with rolling elements (typically balls or rollers) arranged to distribute axial load evenly across the bearing’s raceways, ensuring stable operation even under variable load conditions. Suitable for high-precision applications (precision grade up to P5) and medium to high speeds (≤ 5,000 rpm), these bearings are widely used in aerospace, automotive, and industrial automation industries.

Product Features

Load-Bearing Design

The bearings use a double-row raceway structure (for ball-type models) or symmetrical roller arrangement (for roller-type models) to handle two-way axial loads. Ball-type variants offer a static axial load capacity of 40 kN to 80 kN and dynamic axial load capacity of 25 kN to 50 kN, while roller-type variants (with larger contact areas) deliver higher load capacities: static 60 kN to 120 kN, dynamic 35 kN to 70 kN. The raceways are precision-ground to a surface roughness of Ra ≤ 0.02μm, minimizing friction and wear during load reversal.

Material & Heat Treatment

Constructed from high-purity chrome steel (GCr15SiMn), the bearings undergo carburizing and quenching to achieve a core hardness of HRC 30-35 (for toughness) and surface hardness of HRC 60-64 (for wear resistance). This dual-hardness design allows the bearings to withstand both heavy axial loads and minor impact forces (e.g., sudden load spikes in hydraulic systems). For high-temperature applications (above 150°C), optional heat-resistant steel (SUH616) variants are available, maintaining load capacity up to 200°C.

Precision & Friction Reduction

With precision grades ranging from P6 to P4, the bearings offer tight axial runout tolerances (≤ 0.003mm for P4 grade)— essential for precision machinery like CNC lathes, where even minor axial movement can affect machining accuracy (e.g., causing ±0.01mm deviations in part dimensions). The rolling elements are guided by a brass or nylon cage, which reduces friction between elements by 20% compared to unguided designs, lowering operating temperature (≤ 70°C at 3,000 rpm) and energy consumption.

Usage

Industry Applications

Machine Tool Spindles

In CNC milling machines and lathes, the bearings support the spindle’s axial thrust during cutting operations (e.g., drilling into metal workpieces). The two-way load capacity handles the forward thrust from cutting and the reverse thrust from spindle braking, while the P4 precision grade ensures the spindle remains aligned— critical for achieving tight tolerances (e.g., ±0.005mm) in aerospace components (e.g., aircraft engine parts).

Hydraulic & Pneumatic Cylinders

Hydraulic presses and robotic arms use these bearings to support the axial load of the cylinder rod (which can exert forces up to 50 kN). The double-row raceway design distributes the load evenly, preventing premature wear from constant load reversal (e.g., a hydraulic press lifting and lowering a 1-ton die). The low friction coefficient (μ ≤ 0.001) reduces the force required to move the cylinder, saving energy and extending the cylinder’s service life.

Wind Turbine Generators

In small to medium wind turbines (1-5 MW), the bearings support the generator’s rotor shaft, handling axial loads from wind-induced thrust (forward) and rotor braking (reverse). The heat-resistant steel variant (SUH616) withstands the high temperatures (up to 180°C) inside the generator, while the high load capacity (up to 120 kN static) accommodates the rotor’s weight (up to 10 tons) and wind forces.

Operational Recommendations

Use clean, high-quality lubricants: lithium complex grease (NLGI 2) for temperatures ≤ 120°C, or polyurea grease for temperatures up to 200°C. Lubricate every 5-8 months for continuous operation (e.g., factory machinery) or annually for intermittent operation (e.g., wind turbines). Avoid overloading— operating at more than 120% of rated load can cause raceway damage and reduce life by 50%.

FAQ

Installation & Maintenance

How to ensure proper alignment during installation?

Use a dial indicator to measure axial runout after installation— the runout should not exceed 0.005mm (for P5 grade) or 0.003mm (for P4 grade). Mount the bearing on a clean, flat surface with a perpendicularity tolerance of ≤ 0.01mm/m (shaft vs. housing). For high-precision applications (e.g., CNC spindles), use shims to adjust alignment if runout exceeds the limit— improper alignment can increase friction and reduce load capacity by 30%.

What causes abnormal noise during operation?

Common causes include: 1) insufficient lubrication (add grease until it oozes from the seals); 2) misalignment (check runout and adjust with shims); 3) worn rolling elements (replace the bearing if noise persists after lubrication/alignment). Use a stethoscope to locate the noise source— a high-pitched squeal indicates dry friction, while a rumbling sound suggests misalignment.

Performance & Compatibility

What is the maximum speed for these bearings?

Ball-type variants can operate up to 5,000 rpm, while roller-type variants (with larger rolling elements) have a lower maximum speed of 3,000 rpm. Speed is also limited by temperature— if the bearing temperature exceeds 80°C, reduce speed by 10% for every 10°C increase to prevent overheating.

Can they be used in vacuum environments?

Standard models are not suitable for vacuums (≤ 10⁻³ Pa) because lubricants may evaporate, causing dry friction. For vacuum applications (e.g., semiconductor manufacturing), choose vacuum-compatible variants with solid lubricants (e.g., molybdenum disulfide coatings) and stainless steel components to resist corrosion from vacuum chamber gases.