harmonic gear drive

harmonic gear drive definition: is mainly composed of a wave generator, a flexible gear and rigid gear three basic components, harmonic drive reducer is a by wave generator to produce controllable elastic deformation of the flexible gear, and are engaged with a gear is in rigid to transmit motion and power of the gear transmission. Applied disciplines: Mechanical Engineering (a subject); (2 subjects) transmission; gear transmission (three subjects) harmonic gear reducer is using a planetary gear transmission principle of a new type reducer. Harmonic gear drive (harmonic drive).


Transmission principle


It consists of three basic components:


(1) a rigid gear with an inner ring gear, which is equal to the center of the planetary system;


(2) a flexible gear with an outer gear ring, which is equivalent to a planetary gear;


(3) wave generator H, which is equivalent to the planet carrier.


As a gear reducer, the wave generator is usually used to drive, the rigid wheel is fixed, and the flexible wheel output forms.

The wave generator H is a pole shaped component, and the two ends of the wave generator are provided with a rolling bearing to form a rolling wheel, and the inner wall of the flexible wheel 1 is mutually pressed. The flexible wheel is a thin wall gear which can generate large elastic deformation, and the inner hole diameter of the flexible wheel is slightly smaller than the total length of the wave generator. The wave generator is a component that causes the flexible wheel to generate controllable elastic deformation. When the wave generator is arranged inside the flexible wheel, force the flexible wheel profile by the original circular elliptical, near the two ends of the long axis of tooth and rigid gear tooth meshing and short axis near the ends of tooth and wheel stiffness completely torn off. The teeth of the other segments on the circumference are in a state of engagement and disengagement. When the wave generator along the direction of the icon and continuously rotate, changing of the flexspline deformation, flexspline and rigid gear meshing state is constantly changing, by meshing, engaged, and the mesh and disengaging and engaging in... And again and again, so as to realize the relative stiffness of flexible wheel wheel along the opposite direction of the slow wave generator H rotation. Work, the fixed rigidity wheel, the motor drives the wave generator rotating, soft round as a driven wheel, rotating output drive load movement. In the process of transmission, the wave generator is transferred to a week, the number of cycles of a point on the flexible wheel is called wave number, which is expressed by n. Commonly used is the double wave and the three wave two kinds. The flexible wheel of the double wave transmission is small, the structure is simple, and the transmission ratio is easy to obtain. So it is the most widely used one at present.

























Major advantages


(1) transmission speed ratio. Single stage harmonic gear transmission ratio range of 70~320, in some devices can reach 1000, the multi-stage transmission ratio of up to 30000. It not only can be used to slow down, but also for the growth of occasions.


(2) high bearing capacity. This is because the harmonic gear drive also meshing teeth, double wave transmission also meshing tooth numbers up to total tooth number of more than 30% and soft round the high strength material, between the teeth is surface contact.


(3) high transmission precision. This is because the harmonic gear drive also meshing tooth numbers, average error, namely multi tooth meshing of error have mutual compensation, so the transmission precision. In the case of the same gear precision grade, the transmission error is only about 1/4 of the ordinary cylindrical gear transmission. At the same time, it can be used to change the radius of the wave generator to increase the deformation of flexible wheel so that the tooth gap is very small, and even can be engaged with no side gap.


(4) the transmission efficiency is high, the movement is smooth. Because of the flexspline in transmission process for uniform radial motion, therefore, even if the input speed is very high, tooth relative sliding velocity is very low (so as that of the common involute gear transmission percent -), so the tooth wear is small, the efficiency is high (up to 69%~96%). The meshing and meshing, gear on both sides to participate in the work, so there is no impact phenomenon, smooth movement.


(5) the structure is simple, the number of parts is small, and the installation is convenient. The input and output shaft is the same with the axis, so the structure is simple, and the installation is convenient.


(6) small in size and light in weight. Compared with the general reducer, when the output torque is the same, the volume of the harmonic gear reducer can be reduced by 2/3, and the weight can be reduced by 1/2.


(7) the movement of the confined space. By using the flexible characteristic of flexible wheel, this valuable advantage of wheel drive is unmatched by other transmission.



Application range of harmonic drive reducer


Harmonic gear speed reducer in aviation, aerospace, energy, navigation, shipbuilding, machinery bionics, ordnance, machine tools, instruments, electronic equipment, mining and metallurgy, transportation, heavy machinery, petroleum chemical engineering machinery, textile machinery, agricultural machinery and medical devices more and more widely used, especially in the high dynamic performance of the servo system, the harmonic gear drive also shows its superiority. It delivers power from tens of watts to tens of kilowatts, but large power harmonic gear drives are used for short term work places