Harmonic reducer


Release time:

2021-02-23

Transmission Characteristics and Principle of Harmonic Reducer harmonic gear reducer Harmonic gear reducer is a new type of reducer developed by using the principle of planetary gear transmission. Harmonic gear drive (referred to as harmonic drive), which relies on flexible parts to generate elastic mechanical waves to transmit power and motion of a planetary gear drive. It mainly consists of three basic building blocks: (1) A rigid gear (rigid wheel) with an inner ring gear, which is equivalent to the central wheel in the planetary system; (2) A flexible gear (flexspline) with an outer ring gear, which is equivalent to a planetary gear; (3) Wave generator H, which is equivalent to a planet carrier. Used as a reducer, usually using wave generator active, rigid wheel fixed, flexible wheel output form. The wave generator H is a rod-shaped component, both ends of which are equipped with rolling bearings to form rollers, and are pressed against the inner wall of the flexspline 1. The flexible wheel is a thin-walled gear that can produce large elastic deformation, and its inner hole diameter is slightly smaller than the total length of the wave generator. The wave generator is a component that makes the flexspline produce controllable elastic deformation. When the wave generator is loaded into the flexspline, the section of the flexspline is forced to change from the original circle to the ellipse, and the teeth near the long axis are completely engaged with the teeth of the rigid wheel, while the teeth near the short axis are completely disengaged from the rigid wheel. The teeth of the other sections of the perimeter are in a transitional state of engagement and disengagement. When the wave generator rotates continuously in the direction shown in the figure, the deformation of the flexspline changes continuously, so that the meshing state of the flexspline and the rigid wheel also changes continuously, from meshing in, meshing out, disengaging, re-meshing in..., to realize the slow rotation of the flexspline relative to the rigid wheel along the opposite direction of the wave generator H. When working, the steel wheel is fixed, the motor drives the wave generator to rotate, and the flexible wheel is used as the driven wheel to output rotation and drive the load to move. In the process of transmission, the number of cycles in which the wave generator turns around and a point on the flexspline deforms is called the wave number, expressed in n. Commonly used are two waves and three waves. The flexspline of double-wave transmission has small stress, simple structure and easy to obtain large transmission ratio. Therefore, it is currently the most widely used one. The flexible wheel and the rigid wheel of the harmonic gear drive have the same circumference, but the number of teeth is not equal, usually the difference between the number of teeth of the rigid wheel and the flexible wheel is equal to the number of waves, that is. z2-z1=n Where z2 and z1-are the number of teeth of the rigid wheel and the flexible wheel respectively. When the rigid wheel is fixed, the generator is active, and the flexible wheel is driven, the transmission ratio of the harmonic gear drive is I =-z1/(z2-z1) Double wave transmission, z2-z1 = 2, the number of flexspline teeth a lot. The negative sign above indicates that the steering of the flexspline is opposite to the steering of the wave generator. It can be seen that the harmonic reducer can obtain a large transmission ratio.

1 Basic content

harmonic gear reducer

Harmonic gear reducer is a new type developed by using the principle of planetary gear transmissionReducer.harmonic gear drive(Abbreviationsharmonic drive), it relies on flexible parts to produce elasticitymechanical waveA planetary gear transmission to transmit power and motion.

It mainly consists of three basic building blocks:

(1) A rigid gear (rigid wheel) with an inner ring gear, which is equivalent to the central wheel in the planetary system;

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

(3) Wave generator H, which is equivalent to a planet carrier.

Used as a reducer, usually using wave generator active, rigid wheel fixed, flexible wheel output form.

The wave generator H is a rod-shaped component, both ends of which are equipped with rolling bearings to form rollers, and are pressed against the inner wall of the flexspline 1. The flexible wheel is a thin-walled gear that can produce large elastic deformation, and its inner hole diameter is slightly smaller than the total length of the wave generator. The wave generator is a component that makes the flexspline produce controllable elastic deformation. When the wave generator is loaded into the flexspline, the section of the flexspline is forced to change from the original circle to the ellipse, and the teeth near the long axis are completely engaged with the teeth of the rigid wheel, while the teeth near the short axis are completely disengaged from the rigid wheel. The teeth of the other sections of the perimeter are in a transitional state of engagement and disengagement. When the wave generator rotates continuously in the direction shown in the figure, the deformation of the flexspline changes continuously, so that the meshing state of the flexspline and the rigid wheel also changes continuously, from meshing in, meshing out, disengaging, re-meshing in..., to realize the slow rotation of the flexspline relative to the rigid wheel along the opposite direction of the wave generator H.

When working, the steel wheel is fixed, the motor drives the wave generator to rotate, and the flexible wheel is used as the driven wheel to output rotation and drive the load to move.

In the process of transmission, the number of cycles in which the wave generator turns around and a point on the flexspline deforms is called the wave number, expressed in n. Commonly used are two waves and three waves. The flexible wheel of the double-wave transmission has a small stress, a simple structure, and easy access to largeTransmission ratio. Therefore, it is currently the most widely used one.

The flexible wheel and the rigid wheel of the harmonic gear drive have the same circumference, but the number of teeth is not equal, usually the difference between the number of teeth of the rigid wheel and the flexible wheel is equal to the number of waves, that is.

z2-z1=n

Where z2 and z1-are the number of teeth of the rigid wheel and the flexible wheel respectively.

When the rigid wheel is fixed, the generator is active, and the flexible wheel is driven, the transmission ratio of the harmonic gear drive is

  i=-z1/(z2-z1)

Double wave transmission, z2-z1 = 2, the number of flexspline teeth a lot. Upper formulaminus signIt indicates that the steering of the flexwheel is opposite to the steering of the wave generator. It can be seen that the harmonic reducer can obtain a large transmission ratio.

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