The constant velocity universal joint uses an intermediate frequency heating machine for heat treatment. What is the process like?

The constant velocity joint is an important part of the car that transmits torque to the wheels. It consists of a sliding universal joint at the transmission shaft end, a fixed universal joint at the truck end and a drive shaft in the middle. Constant velocity universal joints have to withstand huge friction during work. We usually use medium frequency induction heating equipment to heat treat universal joints. Induction induction hardening parts are mainly bell-shaped shells and sliding sleeves. The quenched part of the bell-shaped shell is the spline part and the inner ballway, and the quenched part of the sliding sleeve is the spline part and the three pairs of raceway grooves of the sliding sleeve. The specific quenching process is as follows:

(1) Induction quenching of the fairway inside the bell-shaped shell

It is generally carried out by an inner-hole heating inductor, and the effective ring is inlaid with a magnetic conductor to improve efficiency. There are two structures: single-turn and multi-turn. The manufacturing of multi-turn inductors is more complicated than that of single-turn ones, but because the current of multi-turn inductors is smaller than that of single-turn ones, the conductive tube is not easy to burn out, so this structure is still under development. The workpiece is cooled by a liquid sprayer made of insulating material inside the inductor. The spray liquid is first sprayed to the bottom surface of the bell-shaped inner cavity, and then flows through the raceway surface and leaves the workpiece. In order to prevent the bell-shaped shell from deforming, when the inner cavity fairway is heated, there is an auxiliary sprayer on the outer surface for cooling. The heating time of the bell-shaped shell, spline part and raceway part is generally between 3-6s. Especially for the inner raceway, the heating time cannot be long to prevent quenching; when the inner raceway is heated and cooled, the workpiece must be rotated.

(2) Power supply for induction hardening of bell-shaped shells

Due to the deep hardening layer of the spline part, the power frequency range is 3-30kHz, and most manufacturers use an intermediate frequency power supply of 8-10kHz. The power supply power can be selected from 100-300kW according to the size of the part. If the frequency is high, the power can be relatively lower. Nowadays, medium frequency quenching equipment of 160-200kW is mostly used for induction quenching heat treatment.

(3) Quenching method of the spline part of the bell-shaped shell

Since the rod part, the step shaft R and the step surface all need to be hardened, the hardened layer must be continuous, and basically all use the one-time heating method. The sensor must ensure that all parts can be hardened, especially the R part must reach a certain depth. Therefore, the structure is more complex and the effective circle is often composed of multiple segments if the step surface is wide. Quenching cooling is generally performed by a liquid sprayer. Some workpieces are heated and then lowered, and are cooled by flat liquid sprayers on both sides of the machine tool. When splines are heated and cooled, the workpiece must rotate.

(4) Quenching of the sliding sleeve raceway groove

The hardened parts of the sliding sleeve raceway grooves are mainly three pairs of raceway grooves, and the raceway grooves are required to be wear-resistant. There are two ways to quench and heat the raceway groove:

1) Scanning quenching Generally, three pairs of raceway grooves are scanned at the same time. The effective rings are generally connected in series and equipped with magnets. Due to the structural limitations of the raceway groove, the closed end can only be in the top position when the workpiece is scanned by vertical movement. This kind of sensor has two sprayers: one is located below the effective circle and sprays liquid during scanning and quenching; the other is located in the center of the effective circle. When scanning reaches the close end and stops scanning, the central sprayer sprays liquid to The final heating section is quenched. Since the partial wall thickness of the sliding sleeve is extremely thin, there is an auxiliary sprayer on the outside for cooling while scanning and heating. The sliding sleeve scanning quenching has strict requirements on the manufacturing accuracy of the CNC quenching machine tool and the sensor, as well as the sensor cooling water flow rate and quenching liquid flow rate; otherwise, the hardened layers of the three pairs of grooves cannot be consistent. When the sliding sleeve enters the sensor, its positioning angle must be accurate; otherwise, the sensor will be damaged. The cost of this kind of inductor is very expensive, and the manufacturing precision and complexity of the half-ring crankshaft inductor are higher than that of the half-ring crankshaft inductor.

2) One-time heating and quenching. One-time heating and quenching of the sliding sleeve has been used in modern production. The difference between its process and scanning quenching is that after the sensor extends into the sliding sleeve, it is heated and sprayed once. During heating, in order to protect the thin wall from overheating and reduce deformation, there is an auxiliary liquid sprayer outside the sliding sleeve. During the heating process, the outer surface is in the auxiliary liquid spray.

The quenching quality of the constant velocity universal joint seriously affects the operation of the entire machinery. The medium frequency heating machine produced by Zhengzhou Gou's is a good equipment specially used for quenching workpieces such as universal joints. It is favored by customers for its advantages of simple operation and complete functions.