<h2 id="isPasted">Introduction</h2><p>From manufacturing lines and medical devices to packaging and transport systems, robots play a vital role in various sectors that affect our lives. These robots rely on robust mechanical systems to achieve quick, accurate, and reliable movement. Among the essential components of these systems are the gearboxes, which provide the precise torque and positioning required for robotic applications.</p><p>This article explores the importance of precision gears in robotics and explains how to choose the right gear for each application. It also <span>explains how global leader <a href="https://www.nabtesco.de/en/" target="_blank"><strong>Nabtesco</strong></a><strong> </strong>is driving innovation through</span> advanced gear designs tailored for high-performance robots.</p><h2>The Role of Precision Gears in Robotics</h2><p>Robots need precision gears to withstand rapid motion, sudden acceleration, and heavy loads. These gears must work smoothly and reliably, even after millions of cycles. To ensure this, these components have to meet strict performance standards. They need high torsional and moment rigidity to maintain stability during complex tasks. They also have to withstand shock loads and sudden force changes without losing accuracy.</p><p>Since robots are compact machines, space is another challenge. Gears need to be small and lightweight without sacrificing strength or precision. That’s why precision gears are the preferred choice owing to their high efficiency and minimal backlash.</p><h2>Nabtesco's Robotic Gears</h2><p>For <a href="https://www.nabtesco.de/en/industries/robotics" target="_blank">robotics applications</a>, <strong>Nabtesco</strong> offers specialised sets of the RV-N solid-shaft and RV-C hollow-shaft series, designed for 6-axis robots.</p><p>Their unique design delivers power transmission without compromising on rigidity and transmission precision. The cycloid stage, consisting of two offset cams, also makes the gearboxes insensitive to shock loads and enables high-acceleration torque.</p><p>A special feature of the RV-C series is the large hollow shaft with a diameter of up to 138 mm for the feedthrough of power cables and supply lines. Instead of remaining rigid, the shaft is designed to rotate at the output speed. The advantage is that the drive shaft position can be determined directly by a sensor on the hollow shaft.</p><p>You can find more information about the <a href="https://www.nabtesco.de/en/products/cycloidal-gears/rv-c" target="_blank"><strong>RV-C series </strong>here</a> and the <a href="https://www.nabtesco.de/en/products/cycloidal-gears/rv-n" target="_blank"><strong>RV-N series </strong>here!</a></p><h2>Choosing the Right Gears</h2><p>Gears are used in many different robotic applications, but not all gears suit every task. Gears that perform well in a high-speed pick-and-place operation might not meet the precision requirements of a welding or painting robot. Therefore, when selecting gears for robots, it is important to conduct a detailed analysis of the specific requirements.</p><p>It is ideal to begin with the key parameters of robots. The most important factor is the payload, which defines the maximum weight the manipulator can carry. Other critical parameters include rated torque, speed, acceleration, overshoot, positioning accuracy, and repeatability. It is also important to determine whether a hollow shaft is needed to accommodate cables and hoses.</p><h2>Key Technical Considerations</h2><h3>Positioning Accuracy and Repeatability</h3><p>Positioning accuracy indicates the precision with which a desired position can be reached. Repeatability describes the degree of precision when a position is approached repeatedly with the same speed and acceleration. Nabtesco’s precision gears feature very low backlash, typically <strong>0.1–0.2 arcmin</strong>. This high precision ensures reliable performance even during continuous, high-speed operations.</p><h3>Backlash, Hysteresis Loss, and Lost Motion</h3><p>Backlash and hysteresis loss refer to the slight twist that can occur at a gearbox's output shaft when the input shaft is fixed. These factors help measure the precision of a gearbox. Hysteresis loss is the angular tolerance between the input and output shafts at <strong>0 Nm torque</strong>, which is the sum of backlash and friction. Crucial factors affecting backlash are the gearbox design and the precision of the manufacturing process. Lost motion describes torsional rigidity at low torques.</p><h3>Rated Torque and Acceleration Torque</h3><p>To perform operations, robot arms constantly move, speeding up or slowing down. To ensure smooth operations, they need acceleration torque, along with rated torque and emergency stop torque. It is important to note that the acceleration time and the life of the gearbox are directly related. In Nabtesco solutions, both parameters are balanced. The gears are built to support fast acceleration while providing durability and resistance to shock loads.</p><h3>Gear Reduction Ratio</h3><p>Servo motors generally drive the robot axes. However, their specific speeds and rated torque often don’t match the requirements of a robotic system. Gears step in to ensure the required torques and speeds are achieved. A higher reduction ratio increases the average and maximum torque at the gearbox output shaft and reduces the average and maximum speed of the servo motor.</p><h2>Implementation in a 6-Axis Articulated Robot</h2><p>The six-axis articulated arm robot is the most common type in the industry. It belongs to the class of serial kinematics with three vertical and three horizontal rotary axes. The <strong>a</strong><strong>xes 1–3</strong> position the robot’s base, while <strong>axes 4–6</strong> orient the tool or effector. Let’s break down the technical considerations that influence the choice of the gearbox for each axis:</p><h3>Main Axes (Axes 1 to 3)</h3><p>The main axes give the robot its structural strength and stability. Their gearboxes must therefore be both robust and precise. </p><p><strong>Axis 1 (Base)</strong></p><p>Gears here are usually hollow shaft designs. This design is practical as it allows power and data cables to pass through the gearbox.</p><p><strong>Axes 2 and 3</strong></p><p>These axes use solid shaft gears. Without the need for cable or hose feed-throughs, engineers can achieve a smaller, more efficient design. High torque and excellent torsional rigidity are top priorities for the main axes.</p><h2><br /></h2><h3>Hand Axes (Axes 4 to 6)</h3><p>The hand axes drive the end-effector of the robot. They require a lightweight, compact design, as every extra kilogram in these axes can affect performance.</p><p><strong>Axis 4 (Connecting Link)</strong></p><p>Hollow shaft gears are often used. This design reduces weight while providing strong torque and high moment rigidity.</p><p><strong>Axes 5 and 6 (Final Joints)</strong></p><p>These gears focus on compactness. Depending on the application, they may use either solid or hollow shaft designs. The design here is key to maintaining fast, precise movements while minimising wasted space.</p><p>This structured approach ensures that each axis gets a tailored solution. The gears are chosen based on load requirements, motion dynamics, and available space. By matching gear designs to each axis, engineers can optimize performance across the entire system.</p><p><span class="fr-img-caption fr-fic fr-dii"><span class="fr-img-wrap"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1767699556514-1767699556514.png" width="602" class="fr-fic fr-dii" alt="Axis-Specific Gear Requirements in Robotic Systems; Source: Nabtesco Precision Europe GmbH" style="width:800px;height:448.012px" /><span class="fr-inner">Axis-Specific Gear Requirements in Robotic Systems; Source: Nabtesco Precision Europe GmbH</span></span></span></p><h2>Most Commonly Implemented Gears in Robotics?</h2><p>There are two types of gears on the market: cycloidal gears and strain wave gears. The optimal type depends on the requirements of the application. If high positioning accuracy or rigidity are important requirements, for example, cycloidal gears deliver better performance across the board. With rated torques from <strong>100 </strong>to <strong>28,000 Nm</strong>, they also offer a larger performance range. Strain wave gears are ideal in low-torque applications, especially where high performance is needed in compact spaces.</p><h2>Conclusion</h2><p>Precision gears are the backbone of modern robotics, enabling the seamless interaction between power, motion, and control. Whether it's executing movements with pinpoint accuracy or operating reliably over millions of cycles, the right gearbox makes all the difference.</p><p>As illustrated by the example of a six-axis robot, it's clear that gear selection depends on the unique requirements of each axis. That’s where Nabtesco stands out. The company's RV-N and RV-C series gearboxes are explicitly designed for robotic applications, combining high torque capacity, extreme torsional rigidity, and low backlash. For more information, Nabtesco offers different<a href="https://www.nabtesco.de/en/service/downloads" target="_blank"> white papers</a>.</p><p>By matching the right gears to each robotic task, <strong>Nabtesco </strong>helps robots perform better, last longer, and work more reliably across a wide range of industries.</p>

Precision gears drive the performance of robotic systems. Find out how choosing the right gear design enables higher accuracy and long-term durability.

The Critical Role of Precision Gears in Robotics

<h2 id="isPasted">Introduction</h2><p>Once the design is finalized and the technical specifications are defined, the next step is selecting the right gearbox. Factors like compatibility with the motor interface and cost efficiency in drive technology also play a role. <strong>Nabtesco Precision Europe GmbH</strong>, <a href="https://www.nabtesco.de/en/" target="_blank">a global leader in precision gear technology</a>, provides expertise in these areas.</p><p>With over <strong>35 years </strong><strong>of experience </strong>in <a href="https://www.nabtesco.de/en/industries/robotics" target="_blank">robotics</a> and automation, the company specializes in precision gear technology. Its product range includes both strain wave gears and cycloidal gears, making it one of the most comprehensive selections of precision gear solutions on the market.</p><h2>Gearboxes for All Applications With Precision Across the Board</h2><p>High-precision gears are essential in applications that demand accuracy and efficiency. Whether in robotics, automation, or aerospace, choosing the right gearbox ensures smooth operation and optimal torque transmission.</p><p><strong>Christian Otto</strong>, Senior Application Engineer at Nabtesco Precision Europe GmbH, explains: “Our portfolio includes both cycloidal and strain wave gear technologies, each offering distinct advantages while complementing each other. This allows for a scalable product range covering torque values from 7 to 70,000 Nm.”</p><p>With just one dedicated point of contact for all gear solutions, Nabtesco helps optimize design processes, enhances compatibility, and accelerates development cycles.</p><h2>Cycloidal and Strain Wave Gears: A Winning Pair</h2><p>Cycloidal gearboxes are highly rigid and ideal for handling higher torque. On the other hand, zero-backlash strain wave gears perform best in low-torque applications, especially where high performance is needed in compact spaces. The combination of these two gearboxes offers significant advantages for <a href="https://www.nabtesco.de/en/applications/automation" target="_blank">automation</a> applications. The <strong>key factors </strong>include exceptional transmission and repeatability, high single-stage reduction ratios, exceptional shock load capacity (up to 500% of rated torque), compact design, and long operational lifespan.</p><p>On top of it, there’s more to what makes it so effective. <strong>Christian Otto</strong> explains: "In terms of precision, torque capacity, and torque density, these two technologies deliver superior performance. By equipping the larger axes of a robot or machine with cycloidal gearboxes and using strain wave gears in the end-effector area, the entire axis chain achieves maximum precision."</p><h2>How Backlash Defines Precision in Gearboxes?</h2><p>Not all industry experts may readily agree that cycloidal and strain wave gears are the only true precision gear solutions. Here, accurately defining a "<strong>precision gearbox</strong>" helps clarify the debate, as opinions on its definition often differ.</p><p>The accuracy of a gearbox is largely determined by its backlash and hysteresis loss. The lower these values, the more precisely the gearbox operates. In this regard, cycloidal and strain wave gears lead by a considerable margin.</p><p>Here are a <strong>few key points </strong>to put things in perspective:</p><ul><li><p>Strain wave gears are backlash-free.</p></li><li><p>Cycloidal gears have exceptionally low backlash, typically in the range of 0.1–0.2 arcmin.</p></li><li><p>Both technologies feature a maximum hysteresis loss of 1 arcmin.</p></li></ul><p>In <strong>comparison</strong>:</p><ul><li><p>Conventional low-backlash planetary gearboxes typically have backlash of 1-3 arcmin.</p></li><li><p>Standard planetary gearboxes usually have backlash values of 7 arcmin or higher.</p></li></ul><p>This stark contrast highlights why cycloidal and strain-wave gears lead the precision gearing technology.</p><h2>High-Torque Operation with Cycloidal Gears</h2><p>A typical application of the cycloidal and strain-wave gear combination is in a <strong>6-axis robot</strong>. In most cases, <strong>axes 1 to 3</strong> are equipped with cycloidal gearboxes, where high torsional rigidity, robustness, and durability are essential. This makes Nabtesco’s cycloidal precision gear technology a great fit.</p><p>The <a href="https://www.nabtesco.de/en/technology/cycloidal-gears" target="_blank"><strong>two-stage reduction principle</strong></a> of the cycloidal gears delivers exceptional dynamics and smooth operation, ensuring high repeatability and precise path accuracy. Integrated angular contact ball bearings absorb axial and radial loads, as well as bending moments, resulting in high moment rigidity and superior resistance to shock and overload conditions, up to 500% of the rated torque.</p><p>The <strong>cam-and-roller power transmission mechanism </strong>enables nearly full-surface contact, ensuring uniform force distribution within the gearbox. This design results in enhanced rigidity, allowing for smooth transmission of extremely high torques.</p><h2>Compact Strain Wave Gears with Zero Backlash</h2><p><a href="https://www.nabtesco.de/en/technology/strain-wave-gears" target="_blank">Strain wave gears</a> are commonly used in <strong>wrist axes </strong><strong>4 to 6</strong>, and in smaller cobots, they are often integrated into all axes. These compact precision gearboxes offer absolute zero backlash, high repeatability, and maintenance-free operation. They also provide up to <strong>15% </strong>higher torque capacity compared to conventional strain wave gearboxes. All this comes in a compact and lightweight design.</p><p>Manufactured to automotive industry standards at <strong>Ovalo GmbH in Limburg (Lahn)</strong>, these gearboxes meet strict quality requirements. Each unit can be customized to match specific performance, geometry, material, and interface requirements. If needed, customization can also extend to function, component, and system integration.</p><p>The gearboxes are based on a modular product platform with a wide range of sizes, designs, and materials. Additional components such as motors, bearings, seals, housings, sensors, brakes, and ECUs can be integrated. <span>The <strong>key properties,</strong> such as traceability, transmission accuracy, efficiency, and moment of inertia, can be adapted to suit application needs.</span> This flexibility enables engineers to design machines and robots without compromising on performance.</p><h2>Perfect Team for Tool Head and Worktable</h2><p>In <a href="https://www.nabtesco.de/en/industries/machine-tool-construction" target="_blank">machine tool manufacturing</a>, high-reduction precision gearboxes ensure exceptional accuracy. <strong>C</strong><strong>ycloidal gearboxes </strong>provide precise positioning in swivel tables, while zero-backlash strain wave gears in tool heads guarantee precision during machining.</p><p>A high reduction ratio minimizes the moment of inertia between the application and motor, improving control accuracy, reducing drivetrain vibrations, and enabling dynamic positioning. This results in shorter auxiliary times and a more cost-effective machining process.</p><p>The same principle applies to <strong>laser </strong>and <strong>waterjet cutting machines</strong>. Cycloidal gearboxes are ideal for large axes beneath worktables, while compact strain wave gears excel in cutting heads for precise laser or waterjet control. This combination maximizes precision, dynamics, and efficiency.</p><p>Other <strong>applications</strong>, including C-arm scanners in <a href="https://www.nabtesco.de/en/applications/medical-technology" target="_blank">medical technology</a>, antennas, <a href="https://www.nabtesco.de/en/products/rotary-indexers" target="_blank">rotary tables</a>, milling machines, and welding positioners, also benefit from these technologies.</p><h2>Modular Steer-by-Wire Platform for Autonomous Driving</h2><p>Nabtesco’s <strong>CV-EPS (Commercial Vehicle Electronic Power Steering)</strong> is a modular steer-by-wire platform designed for autonomous driving. It features a high-voltage system (AxCu – Axle Steering Control Unit) and a low-voltage solution (24 to 48 volts) for trucks, lorries, and buses. A cycloidal gearbox transmits the main steering torque, while a strain wave gear acts as a preliminary stage between the steering wheel and the cycloidal gearbox.</p><p>“Electromechanical solutions like CV-EPS offer significant advantages over hydraulic systems. They eliminate oil, pumps, and hydraulic lines, allow for integrated assistance functions, and enable customer-specific adjustments such as steering feel. The combination of strain wave and cycloidal gear technology ensures power transmission in a compact space with maximum rigidity and accuracy,” explains <strong>Jonas Kinzel</strong>, Product Manager Wave Gears at Nabtesco.</p><h2>Engineering Support at Every Stage of Development</h2><p>Nabtesco’s cycloidal and strain wave gears don't always need to be used together. Each offers distinct advantages on its own. In most cases, geometric size determines the choice between the two technologies, but there is an overlap where both are viable.</p><p><strong>Jonas Kinzel</strong> explains, "For outer diameters between 100 and 150 mm or torques from 250 to 450 Nm, we offer solutions using either cycloidal or strain wave gears. The choice depends on the application. Cycloidal gearboxes are ideal for high torque, while strain wave gears are best for zero-backlash requirements."</p><p>He further adds that many customers lack the time or resources to explore gearbox technologies in detail. That's why <strong>Nabtesco</strong> offers tailored solutions based on customer requirements regarding cost, performance, weight, and space constraints. The company also provides comprehensive engineering support from design to assembly to help customers streamline their processes.</p><h2>Delivering High Performance Solutions Across Industries</h2><p>Precision gearboxes play a crucial role across <a href="https://www.nabtesco.de/en/solutions" target="_blank">industries</a>, including robotics, machine tools, medical technology, logistics, and mobility. Whether it is pick-and-place, handling, or positioning, almost every system requires a combination of large and small axes. Nabtesco Precision Europe's cycloidal and strain wave gears work together to deliver greater <a href="https://www.nabtesco.de/en/service/added-value" target="_blank">efficiency, flexibility, and cost-effectiveness.</a></p>

Nabtesco provides strain wave and cycloidal gears with a torque range from 7 to 70,000 Nm, enabling consistent performance, seamless compatibility, and cost-effective operation across different applications.

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