{"id":3572,"date":"2026-10-15T15:03:37","date_gmt":"2026-10-15T07:03:37","guid":{"rendered":"http:\/\/www.ps-epsmachine.com\/blog\/?p=3572"},"modified":"2026-10-15T15:03:37","modified_gmt":"2026-10-15T07:03:37","slug":"what-types-of-bearings-are-commonly-used-in-robot-joints-4977-9f0180","status":"publish","type":"post","link":"http:\/\/www.ps-epsmachine.com\/blog\/2026\/10\/15\/what-types-of-bearings-are-commonly-used-in-robot-joints-4977-9f0180\/","title":{"rendered":"What types of bearings are commonly used in robot joints?"},"content":{"rendered":"

If you\u2019ve ever watched a collaborative robot (cobot) lift a fragile wine glass without cracking it, or an industrial robot assemble a smartphone with submillimeter precision, you\u2019ve probably not stopped to wonder what makes that smooth, reliable movement possible. As a robot joint supplier, I get this question all the time: how do we balance the need for ultra-smooth articulation, heavy load capacity, and long-term durability in a component that\u2019s essentially the \u201celbow\u201d and \u201cshoulder\u201d of every robot? The answer boils down to choosing the right type of bearing\u2014and picking the wrong one can lead to costly downtime, erratic movement, or even joint failure mid-operation. Over 15 years in this business, I\u2019ve worked with dozens of robot design teams, from cobot startups to aerospace integrators, and the number one mistake I see is selecting a bearing as an afterthought, rather than as a core component of joint performance. Robot Joint<\/a><\/p>\n

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Let\u2019s break down the four most common bearings we specify for robot joints, along with their pros, cons, and the exact scenarios where each makes sense. This isn\u2019t just generic engineering advice\u2014this is real-world experience from joints that run 24\/7 on assembly lines, cobots that work alongside line workers in warehouses, and surgical robots that operate with human-level precision.<\/p>\n

First up: Crossed Roller Bearings. If you\u2019ve ever designed a robot joint, this is likely the first bearing that comes to mind, and for good reason. Unlike standard bearings that use single rows of rolling elements, crossed roller bearings alternate cylindrical rollers perpendicular to each other in a single raceway. That perpendicular arrangement means they can handle axial loads (forward\/backward force), radial loads (side-to-side force), and moment loads (twisting force) all at the same time\u2014something most other bearing types struggle with. For robot joints, that\u2019s a game-changer. A cobot\u2019s shoulder joint, for example, has to support the weight of the entire arm, handle the twisting force when it reaches to pick up a heavy part, and resist side load when a worker nudges it by accident. Crossed roller bearings excel here. What I love most about them is their compact footprint: they take up less radial space than stacking two separate bearings to handle the same loads, which is critical for robot design teams that are always trying to reduce joint size and weight. I remember a startup cobot maker that was struggling with shoulder joint wobble; they were using two thin ball bearings and getting 0.2mm of play at full extension. Swapping in a standard crossed roller bearing cut play to less than 0.02mm, and they didn\u2019t have to redesign the entire arm casing to fit it. That said, crossed roller bearings aren\u2019t perfect. They\u2019re more expensive than some alternatives, and if they get contaminated with metal shavings or dust (common in heavy industrial settings), the rollers can chip, leading to premature wear. They also require precise mounting\u2014if the raceways are misaligned even by a few microns, you\u2019ll get increased friction and shorter lifespan. For most cobots and medium-load industrial joints, though, this is our top pick.<\/p>\n

Next: Slewing Ring Bearings. Sometimes called \u201cslew drives\u201d or \u201cturntable bearings,\u201d these are essentially large, round crossed roller bearings with built-in gear teeth, designed specifically for rotary motion. You\u2019ll find them in the large, base joints of heavy industrial robots, agricultural robots, and even construction robots\u2014systems that need to rotate 360 degrees while supporting thousands of pounds of load. A welding robot on an automotive assembly line, for example, has a base joint that spins while the upper arm holds a 50kg welding tool. Slewing ring bearings are engineered to handle that combination of high radial load, heavy axial load, and extreme moment load, and their built-in gear teeth let you attach a motor or gearbox directly to the ring, eliminating extra hardware and reducing overall joint height. Early in my career, I worked on a project for a heavy material-handling robot that was failing every 6 months at its base joint. They were using a standard crossed roller bearing and a separate external gear, which added 10cm to the joint height and introduced alignment issues that caused wear. Swapping to a slewing ring bearing cut joint height by 7cm and extended service life to over 3 years, even with 16 hours of daily operation. The downside? They\u2019re bulky and overkill for small joints like a cobot\u2019s wrist, which only needs to rotate a few centimeters of space. They also require regular lubrication, especially in dusty environments, because their open design can trap contaminants. For large, high-load joints, though, there\u2019s no better option.<\/p>\n

Third: Deep Groove Ball Bearings. Don\u2019t let their simplicity fool you\u2014deep groove ball bearings are the unsung workhorses of many smaller robot joints. These are the standard, round ball bearings you\u2019ve seen in everything from bicycle wheels to power tools, but they\u2019re precision-engineered for robot use. They can handle moderate radial loads and light axial loads, and their low friction makes them perfect for high-speed, low-torque movements\u2014like the wrist joints of small cobots or the small rotary joints on a surgical robot\u2019s end effector. For example, the wrist joint of a surgical robot that twists and turns to make tiny incisions doesn\u2019t need to support heavy loads, but it needs to move at 3,000 RPM or more with zero play. Deep groove ball bearings deliver that smooth, fast movement at a fraction of the cost of crossed roller or slewing ring bearings. We use them all the time in small collaborative robot wrists, where the total joint load is under 10kg and size is critical. The tradeoff? They can\u2019t handle heavy moment loads, so you\u2019d never use them for a robot\u2019s shoulder or base joint. If you overload them, the balls can indent the raceways, leading to play and noise. They also have a shorter lifespan under constant high load, so they\u2019re not ideal for 24\/7 industrial operation. But for small, light-duty joints, they\u2019re hard to beat on cost and performance.<\/p>\n

Last: Thin-Section Ball Bearings. If you need something that\u2019s both compact and strong, thin-section ball bearings are the answer. Unlike standard deep groove ball bearings, which have raceways that are much wider than the diameter of the balls, thin-section bearings have raceways that are almost the same width as the balls, making them extremely slim profile. That\u2019s perfect for robot joints where space is at a premium\u2014like the elbow joint of a small cobot, where every millimeter of joint width adds to the robot\u2019s overall arm size and weight. For example, a cobot designed to work inside small, tight spaces (like a warehouse picking bin) needs its elbow joint to be as slim as possible to fit between shelves. Thin-section ball bearings let us design a joint that\u2019s 2cm thick, while still supporting a load of 50kg at the end of the arm. They\u2019re also low-friction, which is great for energy efficiency\u2014critical for battery-powered mobile robots that can\u2019t afford wasted energy on friction. The downside? They have lower load capacity than crossed roller bearings, so they\u2019re best for medium, not heavy, loads. They also require extremely precise manufacturing and mounting, because their slim design means even small misalignment can cause significant performance issues. We often pair them with a small planetary gearbox to boost torque without increasing joint size, which is a popular setup for new cobot manufacturers.<\/p>\n

Now, let\u2019s talk about the factors that really matter when choosing a bearing, because it\u2019s not just about bearing type. Over the years, I\u2019ve learned that every robot joint has four core requirements that dictate the right bearing: load capacity, precision, life span, and cost. Let\u2019s break each down.<\/p>\n

Load capacity is the most obvious, but it\u2019s not just about the total weight the joint supports. You have to calculate combined loads: axial, radial, and moment. A joint that supports a load of 50kg at 1 meter from the joint will have a much higher moment load than a joint that supports 50kg right next to it, so you need a bearing that can handle that twist. We always do full load calculations for every customer, not just go by the joint\u2019s rated weight.<\/p>\n

Precision is another big one. For a surgical robot, you might need positioning accuracy of less than 0.01mm, which means you need a bearing with ultra-low play and consistent friction. For a material-handling robot that moves heavy boxes, you might only need 0.1mm of accuracy, so a cheaper deep groove ball bearing is fine. I\u2019ve had customers come to me insisting they need crossed roller bearings for a wrist joint that only needs 0.1mm accuracy, and it\u2019s my job to explain that a thin-section ball bearing will work just as well, at a lower cost.<\/p>\n

Lifespan is next. Industrial joints that run 24\/7 need bearings that can last 5+ years, while a cobot used only 8 hours a day in a small shop might only need bearings that last 2 years. Contamination is a huge factor here too: if a joint is working in a dusty metal stamping plant, you need a sealed bearing or a bearing with built-in contamination resistance, otherwise dust will get in and wear out the bearing quickly. Crossed roller bearings can be sealed, but they\u2019re more expensive than open bearings, so we factor in the operating environment from day one.<\/p>\n

Cost is always a consideration, but it\u2019s rarely the only one. I\u2019ve seen customers save $50 on a bearing that costs $100 total, only to have the joint fail 6 months later, costing $10,000 in downtime and repairs. We work with every customer to find a balance: if they\u2019re building a low-cost entry-level cobot, we\u2019ll suggest a deep groove or thin-section ball bearing, but if they\u2019re building a heavy industrial robot, we\u2019ll push for the crossed roller or slewing ring bearing that will last for years.<\/p>\n

One more thing I want to emphasize: bearing maintenance is not something you should ignore. I\u2019ve seen perfectly good bearings fail prematurely because the customer skipped lubrication or didn\u2019t clean out contaminants. For open bearings like slewing rings, we recommend greasing every 3 months for industrial use, and for sealed bearings, a periodic check to make sure the seals aren\u2019t damaged. Proper maintenance doesn\u2019t just extend bearing life\u2014it keeps your robot performing smoothly, which is critical for customer satisfaction.<\/p>\n

At the end of the day, every robot joint is a custom design, and the right bearing depends on the application. That\u2019s why we work closely with every customer, from the initial design phase to the final production, to recommend the best bearing type for their specific needs. Whether you\u2019re a startup cobot maker trying to perfect your wrist joint, or an industrial integrator needing a reliable bearing for a 10-ton robot arm, we have the experience and the products to get it right.<\/p>\n

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If you\u2019re designing a new robot joint, or struggling with existing joint performance and reliability, we\u2019d love to hear from you. We can run load calculations, suggest the right bearing type, and even provide custom modifications to fit your unique joint design. Contact our team today to discuss your requirements and find the perfect bearing solution for your robot joints.<\/p>\n

Precision Machining<\/a> References<\/p>\n

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  1. Harris, T. A., & Kotzalas, M. N. (2006). Rolling Bearing Analysis: Advanced Concepts of Bearing Technology (5th ed.). CRC Press.<\/li>\n
  2. Robot Joint Design: A Practical Guide for Collaborative and Industrial Robots. (2021). Robotics Industries Association.<\/li>\n
  3. Slocum, A. H. (1992). Precision Machine Design. Society of Manufacturing Engineers.<\/li>\n
  4. Guidelines for Robot Bearing Selection and Application. (2019). International Organization for Standardization (ISO) 10303-242.<\/li>\n<\/ol>\n
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    Shenzhen Jingcheng Dingyi Forming Technology Co., Ltd.<\/a><\/p>\n

    Address: 1st Floor, Building 3, Huafeng Zhenbao Industrial Park, No.137 Shihuan Road, ShiYan Town, Bao’An District, ShenZhen, PRC
    E-mail: 13071475061@163.com
    WebSite:     https:\/\/www.jctop-cnc.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

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