OVERCOME THE DISADVANTAGES OF THE EXISTING REDUCERS.
Precision reducers are one of the most important and expensive parts of the robot. Generally, industrial robots use Harmonic drive or a cycloid drive (RV). These two reducers have their own advantages and disadvantages. The Harmonic drive is small, light and very precise, but it is relatively weak, very difficult to manufacture and very expensive.
On the other hand, while the cycloid drive is large and heavy and relatively less precise than the Harmonic Drive, it is very powerful and is relatively easy to manufacture and relatively cheaper than the Harmonic drive. Anyway, in common, the two types of reducers are very expensive.
So, we thought about a way to make a cheaper reducer. First, we chose the principle of cycloid drive operation to reduce manufacturing difficulties. In order to reduce the cost of production, such as manufacturing equipment investment costs and processing time, a new low-cost manufacturing process was established, unlike traditional cycloid drives. Finally, we have applied our own special structure to maintain the accuracy that can be less due to the newly developed manufacturing process. This is the history of the development of our Elacloid Drive.
The reducer accounts for approximately 34% or more of the entire robot arm. Therefore, the process for reducing robot costs should start with a reduction in the cost of the reducers. If the cost of the decelerator is reduced, low-cost robots can be developed, which can lead to more robots being distributed. So, if we get more robots to spread, we can move towards the fourth industrial revolution.
We are confident that the Elacloid Drive can lead this price revolution.
Tooth profile of a typical cycloid drive reducers
Tooth profile of our Elacloid drive reducers
We applied the principle of elastic deformation to the pins that mesh with the tooth form of the cycloid disc in order to completely eliminate the fine tolerances necessary for driving between these cycloid discs and pins. If a hollow pin with a spring effect is used, the friction between the parts is reduced, so two parts can slip, since the pin will deform elastically like a spring, even when the pin and disc are fully contact. The hollow pin repeats minor elastic deformation of the tolerance range level whenever it engages with the internal of the disc.
Using this principle, the cycloid disk and the internal pin are slid to each other, and a zero backlash cycloid reducer can be made, which completely removes the fine tolerance required for driving. It can also be miniaturized and light-weight and offers the highest precision of harmonic drive at low weight and size.
Zero backlash cycloid reducers, which are MINTROBOT’s exclusive technologies, and the product developed using this technology is Elacloid Drive (Elastic Deformation Cycloid Drives). The Elacloid Drive is widely seen as a replacement for the Harmonic Drive reducers since it has a good output and mass production.
Micro elastic deformation between internal pin and cycloid disc
Metal, the main material of the reducers, can be an elastomer. After all elastomers are subjected to external forces within the elastic range and elastic deformation occurs, and when the external force is removed and restored to its original position, it cannot return to position that is exactly the same as before the external force was applied. For example, in the case of a reducer, once holding the input shaft, applying a constant load in the + direction, and removing the load, it will restore to a position that is more twisted than the original position. Similarly, if you apply a certain load in the – direction and remove the load, it is restored to a position that is slightly less twisted than the original position. The difference between these two positions is called a hysteresis loss and is usually used to express the precision of a precision reducer.
Hysteresis loss and backlash.
A backlash is a fine clearance between parts that friction to transfer power from the reducer. For example, for a planetary gear reducer that mainly uses involute tooth form, backlash is required between gear teeth in order to move the gear. On the other hand, hysteresis is the deviation that occurs when the load is applied to the +/- direction of the reducer, regardless of backlash, and then the load is removed. Therefore, if a clearance due to backlash is present in the reducer, this will be included in the hysteresis. Therefore, hysteresis is a more stringent criterion for expressing the accuracy of the reducer.
Backlash of Elacloid drive reducer.
Since the gap between the cycloid disc and the inner pin is zero, the reducer itself is structurally zero backlash. However, backlash may occur at the connection points of the input and output shafts depending on the conditions of use of the user.
||FRAME SIZE (3)
||REDUCTION RATIO (4)
* Green Box : Current orderable model
Elacloid Drive : The reducer for precision control
F Series : Flange mount shape
C Series : Cylinder mount shape
(3) FRAME SIZE
The sizes of F Series and C Series are different
(4) REDUCTION RATIO
Reduction ratio of a speed reducer
The Elacloid Drive is provided as the form of a unit with a high rigid cross-roller bearing for load support. Therefore, the user can easily connect the reducer to the structure without using bearing for load support.
The ECD-F series is a cycloid reducer unit which provides a flange type joint. The ECD-F series is normally connected directly to the motor and then joined to the robot's housing as a joint module. The ECD-F series is designed to be compatible with HDS's CSF(G) model, which is the most popular type of harmonic drive reducer available currently, and can be used as an easy alternative to existing Harmonic Drive reducers.
The ECD-C series is a cycloid reducer unit which provides cylinder type mount. The ECD-C series supports hollow construction, which allows for the cable to pass through by using a gear, timing belt, or frameless motor, as well as direct drive.