Pinless cycloidal drive technology refers to a cycloidal structure from which the internal roller-pin (pin) components have been removed. Applying this technology prevents the performance degradation caused by pin wear, which is advantageous for securing long-term operating stability and durability. This article explains pinless cycloidal reduction technology step by step.
Table of Contents
The Definition and Background of Pinless Cycloidal Technology
Key Takeaway — Pinless cycloidal is a structure that removes the pin components which, in a traditional cycloidal reducer, were arranged in the case and engaged with the disc.
Pinless cycloidal drive technology refers to a structure that removes the pin (or roller) components that were arranged at regular intervals inside the case of a cycloidal reducer to engage with the disc, implementing the function instead through external and internal gear teeth. Pins had served the role of meeting the disc’s tooth profile and assisting its motion, but at the same time they increased the part count and acted as a wear factor during long-term operation.
This structural change goes beyond a simple reduction in parts; it leads to the combined effects of a simplified assembly process, fewer part-alignment variables, and a reduced number of potential wear points.
The Assembly Efficiency and Productivity Brought by a Minimized Part Count
Key Takeaway — The primary value of the pinless cycloidal technology structure is a minimized part count. Because no separate pin components have to be managed, the machining, inspection, and assembly processes become simpler, and fewer alignment variables contribute to production-line stability and quality consistency.
When the number of parts decreases, the alignment variables during assembly decrease as well. Variables that used to accumulate part by part, pin alignment error, the pinch tolerance between the pin and the case, and pin-by-pin wear deviation, converge into the single variable of case-machining accuracy, creating a structure favorable to quality consistency and mass production.
Bonsystems has applied the Pinless structure across its BCSA V4 series. This is not merely a cost-side saving but a design choice that raises both long-term operating reliability and mass-production stability together.
Combining a Thin Package with the Pinless Cycloidal Drive Technology Structure
Key Takeaway — When the pin components disappear, the space constraints that were needed to arrange the pins inside the case are also resolved. Bonsystems uses this margin to implement a thin (slim) package, providing a compact cycloidal reducer that fits into tight robot-joint spaces.
Another value of the Pinless cycloidal drive technologystructure is that it naturally combines with a thin design that reduces package thickness. In a traditional pin structure, the case thickness was hard to bring below a certain level because of the space occupied by the pins and the support structure at both ends of the pins.
In a pinless structure, this constraint disappears, so the internal case space can be made more compact. Building on this technology, Bonsystems has developed thin reducers and provides a form suited to space-constrained application environments such as humanoid robot joints and collaborative robot joints.
A thin package means more than simply being thin: it affects the degrees-of-freedom design of the entire robot system. When joint thickness decreases, interference between internal joint components can be reduced, and more degrees of freedom along with cables and drive units can be accommodated within the same external form, raising the flexibility of robot-mechanism design.
Application Value in Humanoid and Collaborative Robot Joints
Key Takeaway — The Pinless cycloidal drive technology structure aligns well with the requirements of humanoid and collaborative robot joints. The reliability that comes from a minimized part count, the space efficiency from a thin package, and the inherent characteristics of the cycloidal mechanism in absorbing accurate motion all work together.
As the lineups of global humanoid finished-product companies expand rapidly, the number of reducers and actuators going into a single humanoid is rising to a scale that is meaningful at the industrial level. The diversification of models among domestic collaborative robot companies also acts as a trend that expands reducer demand.
Amid these market trends, Bonsystems has consistently incorporated Pinless cycloidal drive technology into its own BSR and BCSA series, building up domestic technology-based supply capabilities in the area of humanoid and collaborative robot joint components.
Bonsystems’ Distinctive Cycloidal Reduction Technology
Key Takeaway — Bonsystems takes the Pinless cycloidal structure as its core differentiating technology and applies it across its entire lineup, combining it with the company’s strengths—thin thickness, a minimized part count, and various reduction ratios within a single-stage structure.
Within the trend of localizing cycloidal reducers, Bonsystems defines the pinless structure as its core differentiating technology, has launched the BSR series and the BCSA actuator series, and is also developing new lineups.
Pinless cycloidal drive technology is not a single new feature but a structure that resulted from Bonsystems pursuing part simplification, operating reliability, torque output, and a compact external form all at once. As the humanoid and collaborative robot markets expand going forward, the value of this kind of structure is likely to stand out even more at the component-selection stage.
Frequently Asked Questions (FAQ)
Q: How is Pinless cycloidal different from an ordinary cycloidal reducer?
A: Pinless cycloidal is a cycloidal reduction structure in which the pin components that were arranged inside have been removed. The difference is that, without pins, it uses only external and internal gear teeth, reducing the part count and simplifying potential wear factors.
Q: What is the greatest advantage of the pinless cycloidal structure?
A: The advantages obtained together are improved assembly efficiency and mass-production capability from a minimized part count, a thin package implemented by utilizing the internal case space, and a reduction in variables caused by pin-by-pin wear deviation.
Q: Which robots is Pinless cycloidal drive technology mainly used in?
A: It is expected to be highly useful in applications that simultaneously require power transmission and long-term reliability in tight spaces—such as humanoid robot joints, collaborative robot joints, and industrial automation equipment.
Q: Does the pinless structure preserve the motion characteristics inherent to cycloidal designs?
A: Although it is a structural change that removes the pin components, the operating principle itself—surface contact and eccentric motion based on the cycloidal curve—is preserved exactly. Bonsystems has designed it in a direction that simplifies the parts while preserving these inherent principle-based characteristics.
Q: How does the Pinless structure relate to a thin package design?
A: Removing the pin components frees the internal case space that pins previously required, allowing a more compact, thin package. This makes the reducer well suited to space-constrained environments such as humanoid and collaborative robot joints.
