RAU series crossed roller bearings

HRAU Series Crossed Roller Bearings

An ultra-thin crossed roller bearing with integral inner and outer rings, designed for lightweight, compact precision rotary assemblies such as robots and manipulators.

Series
HRAU Series
Design
Ultra-thin section; integral inner and outer rings
Roller Arrangement
Cylindrical rollers arranged alternately at 90°
Seal Type
Single-sided or double-sided sealed

Key Parameters

SeriesHRAU Series
DesignUltra-thin section; integral inner and outer rings
Roller ArrangementCylindrical rollers arranged alternately at 90°
Seal TypeSingle-sided or double-sided sealed
Load CapabilityRadial load, bidirectional axial load and overturning moment
Rotating RingSuitable for inner-ring or outer-ring rotation
Main BenefitsUltra-thin, lightweight, compact, with integral rings

HRAU Series Crossed Roller Bearings Overview

The HRAU series is an ultra-thin, compact crossed roller bearing developed by minimizing the inner- and outer-ring thickness of the RB-type design. Both rings use an integral construction, making the series particularly suitable for lightweight, space-saving assemblies such as robot and manipulator rotary sections. It can be used where either the inner ring or the outer ring rotates.

Design & Performance Features

  • Cylindrical rollers are alternately arranged at 90°, forming a compact, highly rigid load-carrying structure within an ultra-thin cross-section.
  • A single bearing can accommodate radial loads, bidirectional axial loads and overturning moments.
  • Integral inner and outer rings support applications with either inner-ring or outer-ring rotation.
  • The ultra-thin, lightweight design helps reduce mechanism size, mass and rotational inertia.
  • Suitable for precision mechanisms requiring low weight, compact dimensions and stable rotary performance in limited installation space.

Structure Illustration

Mounting & Operating Notes

Mounting flanges and support housings should provide sufficient rigidity and uniform circumferential fastening to prevent local deformation of the ultra-thin rings.

Mating surfaces should provide good flatness, concentricity and finish; avoid impact or uneven loading during installation.

Fits, tolerances, lubrication and operating clearance should be selected according to load, accuracy, speed and temperature conditions.

Typical Applications

Industrial robot joints, manipulators and end effectors

Precision rotary tables, indexing units and machine-tool rotary axes

Semiconductor, inspection and automation equipment

Medical, optical and compact high-precision rotary devices

Series & Model Information

The HRAU prefix identifies this ultra-thin crossed roller bearing series with integral inner and outer rings. Select the exact model according to bore diameter d, outside diameter D, width B, roller pitch circle diameter dp, basic load ratings, seal arrangement, reference mass and mounting conditions. Refer to the technical table on this page for available models and specifications.

Models & Technical Specifications

Part Number Part NumberDesign Type Design Typed (mm) d (")D (mm) D (")B (mm) B (")Seal SealCr (kN) Cr (klbf)C0r (kN) C0r (klbf)Mass (kg) Mass (lb)
HRA5008 Split Outer Ring50668Single-sided or Double-sided Sealed5.17.190.08
HRAU5008 Integrated Inner and Outer Rings50668Single-sided or Double-sided Sealed5.17.190.08
HRA6008 Split Outer Ring60768Single-sided or Double-sided Sealed5.688.680.09
HRAU6008 Integrated Inner and Outer Rings60768Single-sided or Double-sided Sealed5.688.680.09
HRA7008 Split Outer Ring70868Single-sided or Double-sided Sealed5.989.80.1
HRAU7008 Integrated Inner and Outer Rings70868Single-sided or Double-sided Sealed5.989.80.1
HRA8008 Split Outer Ring80968Single-sided or Double-sided Sealed6.3711.30.11
HRAU8008 Integrated Inner and Outer Rings80968Single-sided or Double-sided Sealed6.3711.30.11
HRA9008 Split Outer Ring901068Single-sided or Double-sided Sealed6.7612.40.12
HRAU9008 Integrated Inner and Outer Rings901068Single-sided or Double-sided Sealed6.7612.40.12

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