Cooling device for interference fit of large-scale workpiece and assembly method thereof

Abstract

The invention provides a cooling device for the interference fit of a large-scale workpiece. The cooling device comprises a liquid nitrogen container and a cooling tank, wherein the liquid nitrogen in the liquid nitrogen container is transmitted to the cooling tank through a pipeline. The cooling device is characterized in that a liquid nitrogen vaporization device is arranged on the pipeline; a cooling medium in the cooling tank is low-temperature gas generated after the liquid nitrogen is vaporized; an installation table for placing a contained piece is arranged at the bottom of the cooling tank; and the liquid nitrogen level in the cooling tank is lower than the table surface of the installation table. The cooling device can be used for controllably cooling a special-shaped contained piece which has large size, complicated structure and asymmetrical shape, so that the dimension of the cooled contained piece is contracted to reach the assembly requirements; the property change of a bearing material caused by rapid temperature reduction can be effectively avoided, thereby avoiding the contained piece from being damaged; the cooling course is safe and reliable; and the maneuverability is strong. The cooling device has the advantages of low time consumption, high efficiency, good interference fit effect, low cost and safe operation and does not generate the conditions that the contained piece is locked and damaged.

Description

technical field [0001] The invention relates to the field of interference fit assembly of workpieces, in particular to an interference fit cooling device for large workpieces and an assembly method thereof, and is especially suitable for a large-scale main shaft system of a fan. The bearing and the bearing seat are interference fit cooling devices and its assembly method. Background technique [0002] In the process of machining and manufacturing, when the fit state of two or more parts is an interference fit, the installation size of the matched contained part is larger than the fit size of the contained part. When the two are assembled, special tools are generally used. Squeeze it in, or use the characteristics of thermal expansion and contraction to heat the containing part to expand the matching size, and then quickly put it into the contained part. After the containing part cools and shrinks, the two will be tightly fitted into one. However, due to the large volume of ...

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Problems solved by technology

[0004] Let’s take the FD100F fan produced by our factory as an example. The height of the bearing seat used in the main shaft system is generally more than 1600mm. The internal structure of the bearing seat is very complicated, and it is very difficult to heat it during shrink fitting.

If the magnetic induction heating system is used for heating, it is necessary to manufacture a magnetic induction rod exceeding 1600mm, which is expensive; after heating to the temperature, it is necessary to lift out the magnetic induction rod and then hang down the bearing housing for assembly, which takes a long time; and because the process consumes If the time is too long, the temperature of the bearing seat will drop and the size will shrink, so that it cannot reach the assembly size. If the assembly is still carried out at this time, it will easily cause the bearing to be stuck, and the risk is high

If the oil heating system is used for heating, the overall heating of the bearing seat can be realized, but due to the complex internal structure of the bearing seat, the residual heating oil inside the bearing seat cannot be cleaned after heating, and the heating oil is easily splashed when assembling the bearing, causing damage to personnel and equipment After the fan leaves the factory, the hot oil remaining inside the bearing seat will also affect the final operation of the main shaft system, damage the main shaft or other components, and have serious safety hazards

If the intermediate frequency heater is used to locally heat the assembly part of the bearing seat, the two can be hot-packed, but the intermediate frequency heater is very expensive, and the cost of heating the large workpiece in this way is too high, thereby increasing the added value of the product , greatly increasing product cost

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