Product Overview
One Way K30X46X28 Stainless Needle Bearings are specialized one-way clutch bearings crafted from stainless steel, designed to allow rotation in one direction while preventing reverse rotation— a critical function in machinery like overrunning clutches, indexing tables, or bicycle freewheels. The “K30X46X28” refers to the key dimensions: 30mm (inner diameter) × 46mm (outer diameter) × 28mm (width)— a compact size that fits into space-constrained assemblies. Unlike carbon steel bearings, the stainless steel construction (AISI 440C) provides exceptional corrosion resistance, making these bearings suitable for wet, humid, or chemical-exposed environments (e.g., food processing, marine equipment, or medical devices). The one-way design uses a cam and roller mechanism (instead of traditional needles) to achieve reliable clutch action, with a high torque capacity that handles sudden load spikes without slipping. They are ideal for applications requiring both one-way rotation control and resistance to rust or contamination.
Product Features
Stainless Steel Material Advantages
Made of AISI 440C martensitic stainless steel, the bearings offer superior corrosion resistance— they can withstand exposure to fresh water, saltwater (marine environments), and mild chemicals (e.g., food-grade cleaning agents) without rusting. AISI 440C has a high chromium content (16-18%) and molybdenum (0.75-1.25%), which forms a protective oxide layer on the surface. The material is heat-treated to HRC 58-62, delivering a static radial load capacity of 28 kN and dynamic radial load capacity of 18 kN— comparable to carbon steel bearings of the same size. Unlike 304 stainless steel (which is softer), 440C resists wear from one-way clutch action, extending service life by 50% in high-cycle applications.
One-Way Clutch Mechanism
The bearing uses a cam-type one-way clutch design (instead of needle rollers alone) to achieve one-way rotation. The inner ring has cam profiles that engage with small rollers (6-8 rollers, depending on size) when rotation is in the “locked” direction— the rollers wedge between the cam and outer ring, preventing reverse rotation. In the “free” direction, the rollers disengage from the cam, allowing smooth rotation with minimal friction (friction coefficient μ ≤ 0.002). The clutch mechanism has a torque capacity of 150 N·m— sufficient to handle the torque from small electric motors (e.g., 1.5 kW motors) or bicycle pedals.
Precision & Environmental Adaptability
Manufactured to ABEC-3 precision grade, the bearings have tight dimensional tolerances: inner diameter tolerance of 0 to -0.012mm, outer diameter tolerance of 0 to +0.02mm, and width tolerance of 0 to -0.02mm. This precision ensures the cam and rollers align correctly, preventing slipping in the locked direction. The bearings operate in temperatures from -40°C to +180°C— suitable for frozen food processing (low temperatures) and industrial ovens (high temperatures). They are also non-magnetic (AISI 440C is weakly magnetic, but non-magnetic variants are available for medical equipment like MRI machines).
Usage
Industry Applications
Food Processing Machinery
In conveyor belts for frozen pizza or canned goods, the bearings prevent reverse rotation of the conveyor (which could cause product jams). The AISI 440C stainless steel resists corrosion from food-grade cleaning agents (e.g., sodium hypochlorite) and washdowns (high-pressure water), complying with FDA standards for food contact. The one-way design ensures the conveyor only moves forward, even if the motor briefly shuts off— critical for maintaining production flow.
Marine Equipment
Used in small boat outboard motors (tiller handles) and anchor winches, the bearings withstand saltwater exposure without rusting. The one-way clutch prevents the anchor winch from reversing (which would cause the anchor to drop unexpectedly), while the high-temperature resistance (up to 180°C) handles the heat from the outboard motor. The compact size (30X46X28mm) fits into the narrow space of the winch housing.
Medical Devices
In hospital bed adjustment mechanisms (e.g., raising/lowering the bed), the bearings allow one-way rotation of the adjustment handle (to raise the bed) while preventing reverse rotation (to keep the bed at the desired height). The non-magnetic variant avoids interference with MRI machines, and the stainless steel construction resists corrosion from hospital disinfectants (e.g., ethanol). The low friction coefficient ensures smooth handle operation for nurses and patients.
Operational Recommendations
Avoid operating at speeds exceeding 3,000 rpm— high speeds can cause the rollers to disengage prematurely from the cam. In chemical environments (e.g., pharmaceutical manufacturing), use a food-grade lubricant (e.g., white mineral oil) to comply with safety standards. Clean the bearing with warm water and mild soap every 2-3 months (for food processing) to remove food residues— do not use harsh abrasives, as they can damage the stainless steel surface.
FAQ
Installation & Maintenance
How to determine the “free” and “locked” rotation directions?
Most bearings have a laser-etched arrow on the outer ring indicating the free rotation direction (the direction the bearing can spin freely). To confirm: 1) Hold the outer ring stationary. 2) Rotate the inner ring— the direction that spins easily is the free direction, and the direction that resists rotation is the locked direction. Install the bearing so the locked direction opposes the reverse load (e.g., for a conveyor, lock the direction opposite to the conveyor’s forward movement).
Can the bearing be disassembled for cleaning?
No— the one-way clutch mechanism (cam, rollers, and springs) is sealed inside the bearing, and disassembly can damage the springs or misalign the cam. For cleaning, wipe the outer and inner rings with a damp cloth (warm water + mild soap) or use a low-pressure air gun to remove dust. For heavy contamination (e.g., food residues), soak the bearing in food-grade cleaner for 10 minutes, then air-dry— do not immerse in water for more than 30 minutes, as this can wash out lubricant.
Performance & Compatibility
What causes slipping in the locked direction?
Slipping typically occurs due to: 1) Misalignment (inner ring is not concentric with the outer ring— check alignment with a dial indicator); 2) Wear on the cam or rollers (replace the bearing if the cam profiles are worn down); 3) Insufficient lubrication (add food-grade grease to the inner ring’s cam area). Slipping can be dangerous in applications like anchor winches— inspect the bearing monthly for signs of wear.
Are these bearings compatible with plastic shafts?
Yes, but the plastic shaft must have a minimum hardness of Shore D 80 (e.g., nylon 66 or POM) to prevent wear from the inner ring. The shaft’s outer diameter should be 30mm ± 0.01mm to ensure a tight fit— a loose fit can cause misalignment, while an overly tight fit can deform the plastic shaft. For high-load applications (≥ 15 kN), use a metal shaft (e.g., aluminum or stainless steel) to avoid shaft deformation.
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