6805 Decoder Bearing — Thin-Section Deep Groove Ball Bearing for Precision Decoder & Encoder Systems
The 6805 Decoder Bearing is an ultra-thin-section deep groove ball bearing engineered specifically for rotary decoder, encoder, and sensor-integrated positioning systems. With a 25 mm bore × 37 mm O.D. × 7 mm width architecture, this bearing delivers the compact envelope and low-friction rotation that modern decoder assemblies demand, without compromising on radial load capacity or rotational accuracy.
Unlike bearings selected on dimensional fit alone, the MTWB 6805 Decoder Bearing is validated as a system-level component — its internal clearance, raceway finish, and grease fill are matched to the torque signature and signal stability requirements of decoder feedback loops.
Parameter Value
Bearing Designation 6805 (Thin-Section Deep Groove)
Bore Diameter (d) 25.000 mm
Outer Diameter (D) 37.000 mm
Width (B) 7.000 mm
Chamfer (rs min.) 0.300 mm
Dynamic Load Rating (Cr) 5.40 kN (approx.)
Static Load Rating (C0r) 2.95 kN (approx.)
Construction Single-row, deep groove
Seal / Shield Options Open, ZZ (metal shield), 2RS (rubber seal)
Precision Grade P0 / P6 / P5 available
Clearance C0 / C2 / C3 / CM (custom on request)
Lubrication Low-torque grease, custom fill volume
Operating Temperature −30 °C to +120 °C (standard grease)
Max Speed (grease) 4,950 rpm (reference)
Specifications reference standard 6805 dimensional data.
Ultra-Thin Cross-Section. The 7 mm width and 0.3 mm chamfer radius allow the 6805 to fit into decoder housings where axial space is at a premium — a critical constraint in rotary encoder and hollow-shaft feedback designs.
Low Frictional Torque for Signal Fidelity. Torque fluctuation directly translates into position jitter in decoder output. The MTWB 6805 employs superfinished raceways and controlled grease fill to minimize running torque variation, typically targeting ≤ 3 N·cm in decoder duty cycles.
Encoder-Grade Rotational Stability. Validated for use in hollow-bore optical encoders rated up to 6,000 rpm, the 6805 delivers the rotational consistency required for quadrature signal integrity.
Customizable Interface. Available with flanged outer rings, locating snap-ring grooves, or custom bore tolerances to suit decoder shaft and housing fits.
6804 Decoder Bearing
The 6805 Decoder Bearing is deployed across:
●Rotary Encoders & Decoders — optical and magnetic encoder feedback shafts
●Servo & Stepper Motor Feedback — rear-shaft encoder mounting
●Industrial Robotics — joint position sensing and arm articulation
●Precision Instruments — medical positioning stages, optical benches
●Automotive Sensors — steering angle and pedal position decoders
●Thin-Wall Mechanical Assemblies — where axial compactness is non-negotiable
The market often groups these bearing types under “low noise” or “precision.” In practice, each serves a fundamentally different functional priority. The MTWB 6805 Decoder Bearing is not a relabeled power tool bearing or a generic EMQ part — it is specified around torque linearity and signal stability, not impact survival or acoustic DBA.
vs. Power Hand Tool Bearing
Dimension Power Hand Tool Bearing MTWB 6805 Decoder Bearing
Primary design driver Impact/shock survival, radial stiffness Torque linearity, rotational smoothness
Typical preload Heavy preload to resist tool chatter Light, controlled preload for minimal drag
Noise target Audible noise reduction (dBA) Torque ripple reduction (signal-level)
Internal clearance C3 or larger for thermal growth C0/C2/CM tight tolerance for low runout
Grease High-viscosity, extreme-pressure Low-torque, clean-room compatible
Duty cycle Intermittent, high-load bursts Continuous, constant-velocity rotation
Failure mode tolerance Survives momentary overload Must not introduce position error
Power hand tool bearings are engineered to survive shock and maintain radial rigidity under hammering and side loads. Bearing preload is deliberately high to eliminate tool chatter, and internal clearance is generous to accommodate rapid thermal cycling. In a decoder application, that same preload would produce excessive running torque and hysteresis in position feedback — a failure mode no amount of noise testing would catch.
vs. Low-Noise EMQ Bearing
“EMQ” (Electric Motor Quality) is a manufacturing quality classification, not an application-specific bearing design. An EMQ bearing is characterized by superfinished rolling contact surfaces and 100% noise testing, with noise grades typically designated Z1, Z2, or Z3 (Z3 being quietest, approximately 32 dB max).
Dimension Low-Noise EMQ Bearing MTWB 6805 Decoder Bearing
What it optimizes Airborne noise (dBA) under motor speed Torque ripple and rotational runout
Specification basis Noise grade (Z1/Z2/Z3), vibration (V1/V2/V3) Torque range, TIR, signal jitter
(application-validated)
Testing regime 100% noise test before packing Noise test plus torque signature validation
Load orientation Radial-dominant, constant direction Radial + light axial, bidirectional
Application fit Motors, fans, pumps, appliances Encoders, decoders, sensor shafts
A Z3 EMQ bearing may run silently at 3,000 rpm — but still exhibit torque variation of several N·cm across a single revolution. In a motor, that variation is absorbed by rotational inertia. In a decoder, it is read as position error. The MTWB 6805 Decoder Bearing is specified against the latter criterion.
Made-to-Order Raceway Geometry. MTWB does not simply grind a catalog 6805 to tighter tolerances. Decoder-grade bearings are produced with application-specific raceway conformity ratios and osculation control, tuned to the radial-to-axial load ratio and speed profile of the target decoder assembly.
Torque-Certified Lots. Every MTWB Decoder Bearing production lot is verified for running torque range before shipment, not merely dimensional conformance. Customers receive torque data as a release criterion — a practice uncommon among general bearing suppliers.
Dual-Market Quality System. MTWB bridges Hong Kong quality management with cost-efficient China manufacturing, supporting non-standard dimensions, special seals, and custom lubrication without the tooling lead times of tier-one bearing majors.
18+ Years OEM Experience. With over 18 years of bearing manufacturing and 100+ active OEM customers across North America and Europe, MTWB has refined the Decoder Bearing specification through field-return analysis — a feedback loop unavailable to catalog-only suppliers.
Customization Without Compromise. Non-standard bore tolerances, flanged configurations, ceramic ball options, and clean-room lubrication are all available on the 6805 Decoder Bearing platform.
MTWB supplies the 6805 Decoder Bearing as a standard catalog item and as a customized OEM solution. Whether you require a one-time prototype lot or a production-volume program with PPAP documentation, MTWB engineering team works from the application torque and signal requirements backward — not from a bearing catalog forward.
Request a quote with your decoder shaft diameter, target torque range, and noise/vibration specification. MTWB will propose the optimal clearance, preload, grease, and seal configuration for your assembly.
October 14,2026
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