The wave reducer, or, as it is also called, wave transmission, is based on transmitting rotational motion, which occurs due to the traveling wave deformation of one of the gears.
Wave transmission
The emergence and further development of wave transmission was carried out in the distant 1959. The inventor, as well as the person who patented this technology, was the American engineer Masser.
The wave reducer consists of several main elements:
- Fixed wheel having internal teeth.
- A rotating wheel having external teeth.
- Drove.
Among the advantages that can be distinguished from this method of transmitting motion are less mass and dimensions of the device, higher accuracy from a kinematic point of view, as well as less dead movement. If necessary, it is possible to use this type of transmission of movement in an airtight space, without using sealing glands. This indicator is most important for such equipment as aviation, space, underwater. In addition, the wave reducer is used in some machines used in the chemical industry.
The principle of operation of the gearbox
From a kinematic point of view, wave transmissions are a kind of planetary gears that has one flexible and gear wheel.
The principle of operation of the wave gear is as follows. The fixed wheel of the device is mounted in the desired housing, and it is performed in the form of a simple gear wheel having internal gearing. A flexible gear wheel is made in the form of a glass having a thin wall that can be easily deformed. In the thicker part of the same wheel, that is, the left, the teeth are cut, while the right part is made in the form of a shaft. The simplest element is the carrier, which consists of an oval cam and a bearing.
The movement itself is due to the fact that the deformation of the ring gear of the flexible wheel occurs.
Gear Designs
Currently, science knows many different designs for the wave gear. Most often, the purpose of all these devices is the conversion of the input rotational motion to the output rotational or output translational. It is also worth noting that wave transmission can be considered as a kind of multi-threaded planetary mechanism. This is quite possible, since these mechanisms have a multi-zone, and if we take into account the gear mechanism, then also a multi-pair contact between the output link and the flexible wheel of the mechanism. It can be noted that with a nominal load on the wave reducer only from 15 to 20% of all the teeth of the device are engaged. For this reason, in all wave transmissions, small-modular mechanisms are used, the number of teeth on which is in the range from 100 to 600. It can also be added that, depending on the number of zones or waves in the device, they are divided into single-wave, two-wave, etc.
Wave gear motor
A description of this type of wave transmission can be made on the basis of the gear motor of the MVz2-160-5.5 model. This model has a dual wave gear. The design of this gearbox consists of a flexible wheel, which is made in the form of a ring with thin walls and two gear rims. In addition, the design also has a cam wave generator common to these parts, which has a flexible bearing.
This model also has several features related to the design of the gearbox:
- The size along the axis of the shaft is small.
- The wave generator is a floating type, and the connection to the motor shaft is articulated.
- At the end of the output shaft of this device are straight-line splines.
This type of gear motor can be used as an individual drive module.
Technical Parameters of Gear Motor
The technical parameters for the wave motor gearbox are some of the main criteria:
- The first parameter that the gearbox must comply with is the torque on the output shaft. It should be - 250 Nā
m.
- The second parameter is the speed of the gearbox shaft. The indicator of this parameter should be - 5.5 min -1.
- The third parameter for this device is the gear ratio. The indicator of this parameter is 264.
- The efficiency of the wave gear motor should be 0.7.
- The parameters of the electric motor for this model are as follows: 0.31 kW of power, rotational speed of 1450 min -1 , the operating voltage for this mechanism is 220 V or 380 V.
- The total weight of the device is 20 kg.
These are the main parameters that are presented to the wave gear motor.
Gear
Not so long ago, engineers created a new type of gear transmission, which in its parameters and design is similar to a planetary gear, but at the same time it has a fundamentally new transmission of rotation. These new inventions are wave gear reducers. In order to transmit rotational motion in these devices, a traveling running deformation was achieved, which lends itself to one of the gear wheels of the gearbox. This invention has proven itself in some kind of tracking systems, as well as in automatic control systems with high accuracy requirements. These gearboxes got their specific purpose because of their characteristics: low physical weight, as well as the small size of the entire device as a whole, which at the same time has a high gear ratio, is characterized by a higher efficiency, that is, efficiency, small backlash, and low wear of gearbox parts. It was these parameters that became decisive in determining the purpose of work for wave gear reducers.
Wave reduction winch
Wave reducers can be of two types - gear and worm gears. The use of a winch in this device found itself only when using a worm-type gearbox. Also in worm-type wave reducers using a winch, there are two ways to position the worm. The lower installation, when it is under the worm wheel, as well as the upper, when the worm is located above the same wheel.
In addition, a winch drive can be used for installation on a spaceship. The winch drive for the spacecraft is a two-stage wave gear. The purpose of this device on such ships is to transfer rotation into a completely sealed space. Since the gearbox is two-stage, the first stage is planetary, and the second is wave transmission. It is also worth noting that it is possible to make the device self-braking. To do this, replace the planetary gear in the gearbox with a worm gear.
Gearbox calculations
As for any other part, to create a gearbox it is necessary to carry out certain calculations that will show whether the device is capable of performing its functions, as well as what material the device should be made of, etc. The main criterion for calculating the wave gear, its performance, is the strength of the flexible wheel. This parameter can be estimated with the help of gear fatigue resistance. The main overall dimension of the gear is the inner diameter of the flexible wheel. It is determined by the approximate dependence of fatigue resistance taking into account normal stresses.