As robots and automation equipment get smaller, the reducer inside the drive unit has to deliver the same output from less space. This article explains what a gear ratio actually determines, how the cycloidal tooth profile spreads load through surface contact, and why that structure suits compact drive design. It also introduces the Bonsystems BSR Series and its pinless cycloid structure.
Contents
Today’s robots and automation equipment are trending toward smaller, lighter designs. This shift allows machines to operate in narrow passageways and tight workspaces that larger equipment cannot reach, and it continues to expand the range of environments where such equipment can be applied.
Even as equipment becomes smaller, it still needs to maintain the performance required for its operation. Meeting this requirement depends heavily on how the drive unit is designed, and within that, the reducer plays a critical role in supporting reliable drive performance.
A reducer converts motor output into the torque and speed needed for a given task, and its characteristics vary depending on the gear structure and design approach. In environments that demand both compact size and sufficient output performance, cycloidal reducers are increasingly being used.
In this piece, we’ll look at how reducers generate torque and what defines their reduction structure, then examine how the structural characteristics of cycloidal tooth profiles benefit equipment design under space constraints.
Why Gear Ratio Matters In Reducer Design
A reducer’s performance is shaped by several factors, including gear structure, load transmission method, and gear ratio. Among these, the gear ratio is a fundamental design factor that determines both output speed and output torque.
The gear ratio represents the ratio between the rotation of the input shaft and the rotation of the output shaft. For example, with a 10:1 ratio, the output shaft completes one rotation for every 10 rotations of the input shaft. Through this process, the motor’s rotational force is converted into torque that the equipment can use.
Obtaining a wide reduction ratio generally calls for more gear stages and a build that can withstand greater loads. As a result, equipment requiring greater torque often ends up with larger, heavier reducers.
Cycloidal Reducers That Deliver Strong Torque In A Small Size
This is where cycloidal technology comes in, enabling sufficient drive performance even in a thin form factor. Unlike conventional gear tooth profiles, cycloidal tooth profiles follow a curved path based on a cycloid trajectory, and this shape changes how load is transmitted.
Commonly used profiles such as involute gears can concentrate load on certain tooth surfaces during power transmission, which may lead to friction and wear from repeated contact. Over time, this can increase backlash, which becomes a factor affecting operational stability in robots or inspection equipment where precise position control matters.
Cycloidal tooth profiles are designed to distribute impact across the tooth contact surfaces. Because the load is carried through surface contact as the gear rotates, it is spread out rather than concentrated on any single point, which helps maintain structural durability even under high load conditions.
Cycloidal reducers are also able to obtain a wide reduction ratio within a single structure, which helps keep the overall drive unit compact. This makes the reducer design worth considering not only for space constrained robot joints and the wheel drive units of unmanned mobile equipment, but for a wide range of industrial applications.
The BSR Series, Beyond A Slim Structure To Real Productivity
The BSR Series applies this cycloidal tooth profile across reduction ratios ranging from 19:1 to 99:1, with model-by-model specifications published on the official BSR series page. It maintains a thin, slim structure even at wide reduction ratios, enabling compact drive unit design. Since a device’s interior houses various components alongside the motor and reducer, a more compact drive unit can increase design freedom and improve space efficiency across the entire system.
Alongside internal design refinement, it’s equally important to maintain consistent quality throughout actual production. Within the BSR Series, the 070 and 080 lines adopt a pinless structure, preserving the durability characteristics of the cycloid reduction method while also factoring in production efficiency.
This approach simplifies the structure by removing components such as pins, reducing the total part count. That makes assembly easier and reduces the margin for error during the assembly process. This is a meaningful advantage in mass production, and it helps maintain consistent product quality.
The BSR Series brings together compact size, strong torque performance, and manufacturability in a single cycloidal reducer, offering a new option for drive unit design in space constrained equipment. Drawing on experience across a wide range of equipment applications, Bonsystems proposes solutions tailored to each customer’s development environment and requirements. If you have questions about reducer design or would like additional materials on the BSR Series, please reach out through our website.
F.A.Q
Q: What are the key characteristics of a cycloidal reducer?
A: Because a cycloidal tooth profile transmits power through surface contact as it rotates, it reduces the load concentrated on any single area. This structure helps limit stress and wear on components, supporting stable performance and durability even in repetitive operating conditions.
Q: Why does reducer size matter in robots and automation equipment?
A: The size of a reducer affects not just the drive unit but the design of the entire piece of equipment. A smaller reducer footprint allows wiring, sensors, and control components to be arranged more efficiently, which is especially important in robot joints and in automation equipment installed in tight spaces.
Q: Why does a single-stage reduction structure matter?
A: Obtaining a wide reduction ratio from one gear stage means the drive unit does not have to stack additional stages to reach the torque a task needs. Keeping the reduction in a single structure helps hold the package thin and keeps the part count simpler.
Q: What are the characteristics of a pinless cycloidal structure?
A: A pinless structure simplifies the internal design by removing the separate pin components from inside the case. With fewer parts, the assembly process becomes simpler, and reducing assembly variation helps maintain consistent quality across products, which also contributes to production efficiency.
Q: What kinds of equipment are cycloidal reducers well suited for?
A: Cycloidal reducers are well suited for equipment that requires strong torque within a limited space, including humanoids, collaborative robots, and unmanned mobile equipment such as AGVs and AMRs. Because of their structural stability, they are also worth considering for environments that demand reliable handling of repetitive tasks and high loads.
