The reducer, a core component of industrial robots, is the heart of mechanical transmission. The speed and precision of a robot are related to the reducer. The reducers used in industrial robots mainly include: harmonic reducers and RV reducers.
Harmonic reducer
• The motor shaft connects to the wave generator, and the robotic arm connects to the rigid base of the flexible gear ring.
Flexible gear rings have N fewer gear positions than rigid gear rings.
For every revolution of the wave generator, the flexible gear ring moves N gear positions.
• It can achieve a very high reduction ratio.
RV reducer
RV reducer structure
RV-E is a two-stage reduction gear. The first stage of reduction is the external meshing of the input gear and the spur gear. The three spur gears are symmetrical about the output shaft at 120° intervals.
The second-stage reduction gear drives the eccentric shaft via a spur gear, which in turn drives the RV gear mounted on the eccentric shaft, causing the two RV gears to move eccentrically. The two RV gears drive the output shaft with a 180° phase difference to provide a balanced load.
RV-C is a two-stage reduction gear. The first stage of reduction involves the external meshing of the input gear and the first center gear, followed by the external meshing of the second center gear and the spur gear. The three spur gears are symmetrical about the output shaft at 120° intervals.
The second-stage reduction gear drives the eccentric shaft via a spur gear, which in turn drives the RV gear mounted on the eccentric shaft, causing the two RV gears to move eccentrically. The two RV gears drive the output shaft with a 180° phase difference to provide a balanced load.
RV deceleration principle
Cylindrical needle rollers are installed inside the inner ring of the housing. The eccentric motion of the RV gear causes the needle rollers to mesh and disengage with the cycloidal RV gear teeth, resulting in multiple sets of RV gear teeth meshing with the needle rollers simultaneously, thus improving load capacity. Since the number of RV teeth is one less than that of the needle rollers, when the eccentric shaft rotates one revolution, if the housing is fixed, the RV gear rotates one tooth angle in the same direction as the input shaft.
The output can be a drive shaft or a case. If the case is fixed, the drive shaft is the output, and the output is in the same direction. If the drive shaft is fixed, the case is the output, and the output is in the opposite direction. By changing the fixed and output components, different transmission ratios can be obtained.
