The Role of Flexible Bearings in Robotics

Flexible bearings produced by TPI are used in Strain Wave Gears transferring the waveform and accommodating radial loading.

TPI through PIB  offers the SX series, for their precision tolerance class. With designs tailored for high-speed applications and compact systems, they improve both performance and reliability in robotic tasks. Bearings for robotics applications are available for purchase through PIB Sales, ensuring access to top-tier components.

What are Flexible Bearings?

Flexible bearings are specialized high-precision rolling elements engineered to accommodate elastic deformation while maintaining exceptional load-bearing capacity and rotational accuracy. Unlike conventional rigid bearings, flexible bearings are designed to adapt to non-uniform force distribution, which makes them indispensable in high-precision applications such as robotic strainwave drives (harmonic drives). Their unique structural composition consists of an inner ring, an outer ring, precision steel balls, and a cage (retainer), ensuring smooth and reliable motion transmission.

In robotic applications, particularly in precision actuators and harmonic gear systems, flexible bearings play a crucial role in minimizing backlash, improving torque transmission efficiency, and maintaining long-term accuracy. The strainwave gear mechanism, a critical component in robotic motion control, relies on the controlled flexibility of these bearings to transmit deformations effectively, allowing smooth and continuous motion transfer between the wave generator and the flexspline.

Structural Composition and Functionality

Flexible bearings in TPI’s SX series feature high-performance materials and precision-engineered geometries optimized for dynamic load conditions. These bearings can withstand radial, axial, and moment loads, making them essential in robotic joint actuation, precision rotary tables, and high-torque applications.

Key components include:

• Inner ring & outer ring: Designed to accommodate controlled deflection while ensuring structural integrity.
  
• Precision balls: Provide smooth rotation and load distribution.
  
• Cage (retainer): Ensures uniform ball spacing and prevents unwanted displacement.
  

The unique ability of TPI SX Series Bearings (e.g., SX05T01T2, SX06T01T2, SX07T01T2, SX09T01T9X, SX12T01T9X) to accommodate controlled deformation without sacrificing load capacity makes them an ideal solution for robotic precision gearing systems.

Tolerance and Dimensional Accuracy

In precision robotics, dimensional and running accuracy are paramount. TPI flexible bearings adhere to international tolerance standards defined by ISO 492 and JIS B 1514, ensuring consistent performance under high-load and high-speed conditions. These standards categorize bearings into different tolerance classes, determining radial runout, bore diameter accuracy, and rotational precision.

TPI’s manufacturing process ensures that their SX series flexible bearings meet Class 2 precision, which offers superior rotational accuracy, minimal deviation in bore and outside diameter tolerances, and high-speed capability.

In conclusion, flexible bearings are an essential component in robotic harmonic drive systems, enabling ultra-precise motion control, reduced friction losses, and extended service life. With TPI’s extensive portfolio of SX series flexible bearings, engineers can select high-performance solutions that comply with stringent international standards, ensuring optimal robotic actuation and motion stability.

Common Types of Flexible Bearings Used in Robotics 

Flexible bearings play a fundamental role in high-precision robotic applications, particularly in strainwave drive mechanisms. These bearings are designed to accommodate controlled deformation while maintaining high load-bearing capacity, minimal backlash, and superior rotational accuracy. TPI’s SX Series flexible bearings are engineered to meet the demanding performance requirements of robotic actuators, ensuring smooth and reliable transmission of motion in harmonic drives, collaborative robots, and industrial automation systems.

Overview of the TPI SX Series

The TPI SX Series consists of high-precision thin-section flexible bearings designed specifically for harmonic drive applications. These bearings are manufactured with tight tolerance control, optimized internal geometry, and advanced material selection, ensuring exceptional durability, stiffness, and reduced friction losses.

Each bearing in the SX Series features:

• Optimized raceway design to enhance load distribution and reduce stress concentration.
  
• Lightweight construction with high rigidity, making them ideal for weight-sensitive robotic applications.
  
• Advanced lubrication retention for extended service life in high-cycle applications.
  
• Minimal axial and radial play to enhance accuracy and efficiency in robotic motion control.
  

Detailed Breakdown of TPI SX Series Bearings

SX05T01T2 – Compact and lightweight for precision robotics

The SX05T01T2 model is the most compact option in the SX series, featuring an inner diameter (d) of 25.074 mm and an outer diameter (D) of 33.9 mm. With a narrow profile (B1 = 6.41 mm), it is ideal for high-precision robotic joints and small-scale actuators where space constraints are a critical factor. This bearing provides smooth motion transfer with minimal resistance, making it an optimal choice for medical robots, micro-manipulators, and precision positioning devices.

SX06T01T2 – Versatile for medium-sized harmonic drives

The SX06T01T2 bearing offers a larger inner diameter (33.306 mm) and outer diameter (41.73 mm) while maintaining a similar narrow cross-section (B1 = 6.68 mm). This model provides an excellent balance between rigidity and flexibility, making it well-suited for mid-sized robotic arms, exoskeletons, and industrial automation systems that require accurate torque transmission and minimal backlash.

SX07T01T2 – Enhanced load capacity for industrial robotics

With an inner diameter of 35.57 mm and an outer diameter of 49.08 mm, the SX07T01T2 model is designed to withstand higher loads while maintaining optimal deformation properties. Its increased width (B1 = 8.12 mm) provides enhanced stability, reducing unwanted vibrations in robotic motion control systems. This bearing is frequently used in collaborative robots (cobots), SCARA robots, and precision rotary tables.

SX09T01T9X – Heavy-duty bearing for high-torque robotic actuators

One of the most robust bearings in the SX lineup, the SX09T01T9X model features an inner diameter of 45.21 mm and an outer diameter of 61.34 mm, with a significant increase in width (B1 = 6.32 mm, B2 = 9 mm). This configuration allows it to handle higher radial and axial loads, making it an optimal choice for industrial robots, heavy-duty automation, and robotic welding arms that demand maximum durability and long-term reliability.

SX12T01T9X – Maximum stability for large-scale robotic applications

The SX12T01T9X is the largest and most robust bearing in the SX series, with an inner diameter of 58.928 mm and an outer diameter of 79.76 mm. Its significantly larger cross-section (B1 = 8.6 mm, B2 = 11.82 mm) enables it to support extreme loads and high-speed rotational motion. This bearing is extensively used in robotic milling machines, large industrial automation systems, and aerospace applications, where ultra-precise positioning and extreme durability are required.

For high-precision applications with limited space, the SX05T01T2 and SX06T01T2 models offer compact designs with minimal weight. Mid-range solutions like the SX07T01T2 provide enhanced rigidity for stable robotic motion. For heavy-duty applications, the SX09T01T9X and SX12T01T9X offer superior load-handling capabilities and long-term operational reliability.

TPI Bearings ensures all SX Series models comply with ISO 492 and JIS B 1514 standards, guaranteeing high precision, minimal runout, and superior durability. Engineers and robotics developers can purchase these bearings through the PIB Sales distributor, ensuring authentic TPI products with full technical support.

Flexible Bearings for Strainwave Drive

A strainwave drive operates on the principle of controlled deformation to achieve precise motion control with minimal backlash. In this system, the flexible bearing is installed within the wave generator, allowing it to deform in response to the elliptical motion induced by the generator. This deformation is transmitted to the flexspline, which in turn engages with the circular spline, producing highly accurate and repeatable motion.

Flexible bearings differ from conventional ball bearings due to their unique internal geometry and ability to flex without compromising rotational efficiency. These bearings consist of:

• Inner ring: mounted onto the wave generator, transmitting deformation forces to the outer ring.
  
• Outer ring: provides structural integrity while allowing for controlled elastic deformation.
  
• Precision steel balls: ensures low friction and smooth rolling motion to minimize resistance during deformation cycles.
  
• Retainer (cage): maintains proper spacing between balls, optimizing load distribution and reducing wear.
  

This construction allows flexible bearings to operate efficiently under constant load variations, making them an indispensable solution for robotic joints, automation actuators, and precision gearing systems.

Proper installation of flexible bearings is critical to ensure performance in strainwave drive applications. Engineers must carefully follow installation guidelines, including:

• For single-piece retainers: A shoulder stop mechanism should be designed on the wave generator to prevent the retainer from dislodging during operation.
• For double-piece retainers: Engineers must avoid interference with the retainer during installation to maintain bearing integrity and prevent premature wear.

Flexible bearings are engineered to maximize efficiency, reduce wear, and enhance precision in robotic systems. Their ability to adapt to high-torque applications while maintaining zero-backlash performance makes them the go-to solution for advanced automation and motion control technologies.

FAQs

Q:  What is PIB Sales, and what products do you offer?

A: PIB Sales is a Leading Bearing Distributor specializing in high-precision bearings for the robotics, automation, and industrial sectors. We provide a wide range of flexible bearings, ball bearings, roller bearings, and custom bearing solutions from top manufacturers, including TPI Bearings.

Q:  How do I search for a specific bearing on PIB Sales?

A: You can use the search bar on the PIB Sales website by entering:

• The bearing part number (e.g., SX05T01T2, SX09T01T9X).
• The bearing type (e.g., flexible bearings, ball bearings).
• The manufacturer name (e.g., TPI Bearings).
  You can also filter products by dimensions, load capacity, and application to find the most suitable option for your needs.
  

Q: How do I place an order for bearings?

A: Ordering from PIB Sales is quick and easy:

• Browse the catalog and select the bearing you need.
• Add the product to your cart.
• Proceed to checkout and enter your shipping details.
• Choose a payment method and complete your order.
• Receive tracking information and updates on your shipment.

Contact us at [email protected] or call 1-800-228-8895.

Q: Can I find TPI Bearings on the PIB Sales website?

A: Yes! PIB Sales is the USA Authorized distributor of TPI Bearings, offering a full selection of TPI flexible bearings for strainwave drives, harmonic drives, and robotic applications. You can easily browse TPI’s SX Series and other precision bearings directly on our platform.

At PIB Sales, you can browse, compare, and purchase TPI Bearings for robotic and industrial applications. Whether you need flexible bearings for strainwave drives, high-precision ball bearings, or custom solutions, our catalog provides a comprehensive selection of TPI-manufactured products.

Visit PIB Sales online store today to find genuine TPI Bearings or explore a wide range of bearing solutions for the robotics industry.