Planetary mechanisms (1979)

An excavator at a construction site.

Rotating apparatus in the textile industry.

Rotating helicopter propeller blades.

In all machines, the transfer of motion from the engine to the rotating device is carried out by a transfer mechanism.

Wrench.

Planetary gear mechanisms.

A sample of the simplest gear mechanism.

It consists of two gears with fixed axles.

A sample of a planetary mechanism, this is a mechanism with movable axes.

A gear wheel with a movable geometric axis is called a satellite.

The rotating link in which the satellite axis is installed is the driver.

There may be several satellites in the planetary mechanism.

Satellites rotate around their axes and at the same time move with the driver.

A sample of such a planetary mechanism.

The fixed axis of the driver is called the main axis.

Gears whose axes coincide with the main axis are called central.

The simplest planetary mechanism has one leading link.

The leading link can be a driver or a satellite.

Planetary mechanisms with two or more leading links are called differential mechanisms or differentials.

Classification of planetary transmissions by V.N. Kudryavtsev.

Samples of planetary transmissions with classification 2k-h.

They can be manufactured with conical and cylindrical gears.

A sample application of planetary gear is an aircraft engine gearbox.

In the 3k planetary gear, the main links are 3 central wheels, and the driver serves only for the installation of satellites.

The next coaxial planetary gear is k-h-V.

The torque from the satellite is transmitted by means of a double articulated coupling to the shaft v.

The angular velocity of the shaft is equal to the angular velocity of rotation of the satellite.

For misaligned planetary transmissions, the satellite is the leading link.

An example of a misaligned planetary gear is the rotation mechanism of the excavator platform.

Kinematic analysis of planetary mechanisms is carried out using the method of motion reversal.

Determination of the gear ratio from one link to another.

Transfer ratio indexes.

Determination of the speed of the third link.

An example of summing angular velocities is the drive of a spinning-belt machine.

Kinematic transmission capabilities with a negative gear ratio.

The gear ratio can be increased if two mechanisms are connected in series.

In planetary gears with two pairs of wheels with external teeth, the gear ratio is positive.

If the gear ratio is close to one, then the transmission has great kinematic capabilities.

Kinematics of the differential of the car.

When turning, the wheels of cars rotate at different speeds and go through different paths.

The driveshaft transmits motion from the car engine through a gear pair to the driver, and then through satellites to the bevel gears connected to the wheels of the car.

In rectilinear motion, the entire gear train rotates as one.

When turning, the speed of one central gear differential wheel increases, and the other decreases.

This speed difference is provided by the rotation of the satellites around their axes.

Losses of mechanical energy in transmissions.

Losses in planetary and conventional transmissions may differ.

Determination of efficiency in planetary gears.

In coaxial planetary gears with cylindrical gears, the conditions of alignment, proximity and assembly must be met.

The alignment condition can be expressed in terms of the number of teeth of the wheels of the planetary mechanism.

Reference book planetary transmissions.

Table "Alignment conditions of planetary gears".

Neighborhood condition.

If the number of satellite teeth is selected incorrectly, the transmission is not assembled.

Samples of planetary transmissions.

The 2k-h single-row transmission is characterized by ease of manufacture and high efficiency.

Planetary transmission with a 2k-h twin-shaft satellite allows you to get large gear ratios with high efficiency and small dimensions.

The transmission with conical wheels is used as a differential.

The 3k transmission is the most contact, allows you to get large gear ratios.

The planetary mechanism in the loom.

A progressive solution is the embedding of planetary gears in the actuators of machines.

Various examples of the use of planetary gears.