What is the basic structure of the slewing drive?

Slewing drives are made by manufacturing gearing, bearings, seals, housing, motor and other auxiliary components and assembling them into a finished gearbox. This article will introduce what is the basic structure of the slewing drive.

The following knowledge points are listed below:

The basic structure of the slewing drive

Slewing drive support device

The main part of slewing drive

The specifications for slewing drives and gears varies depending on the material the gear is composed of. However, a majority of the drives and gears commonly used are composed of steel and phosphor bronze. According to an extensive series of tests by , chill-cast nickel-phosphor bronze ranked first in resistance to wear and deformation.

1. The basic structure of the slewing drive

Slewing drive usually consists of two parts: slewing support and slewing drive. The slewing support device is used to connect the slewing part of the crane with the non-slewing part, and to provide the constraints required by slewing movement to ensure that the slewing part has certain movement. At the same time, it provides a stable support for the slewing part to withstand the vertical load, horizontal load and overturning moment from the slewing part.The rotary drive device is used to drive the rotary part relative to the non-rotary part to realize the rotary movement.

2. Slewing drive support device

The slewing support devices are mainly divided into column type and rotating disk type. The selection of what kind of slewing bearings should be determined according to the specific requirements of use, the processing conditions of the crane factory and the characteristics of various slewing bearings.

The column type slewing support device mainly consists of the column and the upper and lower supports.According to whether the column is a rotating part or a non-rotating part, it can be divided into two forms: rotating column type slewing support device and fixed column type slewing support device.

(1) rotating column type slewing support device

In the rotating column type slewing bearing device, the vertical column and the rotating part are connected to turn around together and become the rotating column.The rotating column relies on the support of the upper and lower supports, and realizes the rotary movement through the driving device.

Because of its large diameter, the upper support is not suitable for radial bearing, usually by installing a horizontal roller and raceway to replace.The general form is to install the horizontal roller on the rotating column, and install the raceway on the structural parts of the non-rotating part, sometimes also can be used to install the horizontal roller on the non-rotating part

(2) fixed column type slewing support device

In the fixed column type slewing bearing device, the city column is fixed on the foundation structure.Upper and lower supports are provided at the upper and lower ends of the column.The same rotating part, which looks like a bell jar, is supported on the upright column up and down, and the driving device turns the bell jar to realize rotary movement.Fixed column slewing bearings are often used in floating cranes and sometimes in stationary cranes.

The rotating disc type slewing support device is mostly used in the tyre-type/crawler crane, which can also be divided into supporting roller type and rolling bearing type.Support roller has gradually faded out of the market, the main use of rolling bearings.The inner and outer rolling rings are fixed with high strength bolts on the rotary platform or chassis frame respectively.

3. The main part of slewing drive

In order to ensure the reliable operation of the rotating machinery and prevent overload, it is generally necessary to install a limit torque limiter in the transmission system.Most active machines use electric motors, but most mobile slewing cranes use internal combustion engines.Most of the rotary driving elements use gear (or needle wheel), but some cranes use driving roller or rope traction.

According to the use and construction of the crane, the rotary drive device can be arranged in two ways:

The slewing drive is mounted on the slewing part of the crane, and the last stage of the large gear ring (or needle wheel) is mounted on the rack of the non-slewing part. In the slewing mechanism of the port crane, this form is adopted in most cases.

Slewing drive is mounted on the non-slewing part of the crane, and the last stage of the large gear ring (or needle wheel) is mounted on the slewing part of the crane, which is sometimes used in some large fixed column cranes and tower cranes.

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