Induction heating of bearings and clutch for landing

How Landing Heating Works

As the temperature increases, the metal part expands. The heated covering element is installed on the shaft or in the landing place, after which the desired tension is formed during cooling. Unlike heating with a burner, the inductor can be designed for the geometry of the part and repeat the specified cycle in power, time or temperature control signal.

For bearings, it is critical to comply with the permissible temperature set by their manufacturer: restrictions may depend on steel, heat treatment, separator, seals and lubricants. For couplings and massive bushings, the uniformity of temperature by section and sufficient heating of the inner zone are important. If the outer surface is heated quickly, this does not mean that the landing diameter has already expanded by the calculated value.

heating before mounting bearings, couplings, bushings, rings and wheels;

local heating of the covering part without obligatory heating of the shaft;

repeatable program for parts of the same nomenclature;

the ability to use replaceable inductors for different sizes.

Base data for calculation

The main initial parameter is the required increase in the internal diameter. It is determined by the actual tension, the mounting gap and the tolerances of the mating parts. Together with the drawing, it is desirable to transfer data on the method of feeding and removing the product: the heated heavy coupling must be safely moved and installed for a limited time.

material, weight, external and internal diameters, part width;

fit size, tension, tolerances and required mounting clearance;

initial and permissible final temperature;

the required heating time and the number of parts per shift;

presence of lubricant, polymer separators or seals;

manual or mechanized loading, tooling mass;

allowable temperature drop by detail and method of control.

Selection of installation series

AVVS can be used for small rings and local areas. ABB and AVZ are suitable for many serial operations with bearings, bushings and medium-sized couplings. AVN is advisable to consider for massive parts and a large section when a deeper warming-up is required. LN is convenient for single repair and parts to which the operator brings a remote inductor. The choice of frequency depends on the diameter, wall thickness, magnetic properties of the material and the required uniformity.

For repeated nomenclature, the most stable result is given by an inductor made for a specific part. If necessary, the installation can be used with several replaceable inducers for different sizes. Universal inductor expands the range of parts, but can be inferior to specialized in the speed and uniformity of heating.

Example of an approximate calculation of expansion and time

Indicative example for primary assessment. For steel coupling with a planting diameter of 200 mm, take the linear expansion factor 12 × 10⁻⁶ 1/°C and heat from 20 to 180 °C. Estimated increase in diameter: 200 × 12 × 10⁻⁶ x 160 = 0,384 mm. The adequacy of the expansion shall be checked against the actual tension, tolerances and the required mounting gap.

If the mass of the coupling 20 kg, and the average heat capacity of steel adopted 0,5 kJ/(kgC), the useful heating energy will be 20 × 0,5 × 160 1600 kJ. With the pre-accepted overall efficiency of the 60 % process, the required energy from the network is about 2667 kJ. With an average power consumption from the 40 kW network, the idealized time is about 67 seconds. In practice, account is taken of heating by thickness, heat loss, tooling and aging; therefore, the real cycle is determined by testing.

Equipment, tests and warranty

UralInduktor forms the concept of the workplace and the technical solution, and the Chinese factory performs detailed design and manufacturing. A simple inductor is usually included in the cost of installation. The set of replaceable, detachable or structurally complex inductors is agreed and calculated separately.

The equipment is checked at the plant with the inductor ordered, then again in Miass without load at full connection. Russian-language management and documentation are provided. commissioning is carried out by the customer with tests on his details and the signing of acts. The warranty is 18 months; the contract establishes the countdown from the date of shipment or the signing of the commission act. Price on request.

What to send for selection

Send drawing covering parts and shaft, mass, material, tension, tolerances and allowable temperature. We will calculate the required expansion, offer a series of installation and the concept of the inductor. The cycle time and heating uniformity will be confirmed by tests on the real part.