中频加热炉淬火主顶尖的转速应如何选取？

对淬火工件加热时转速的选取，从工件加热均匀性来讲，转速越快，由于感应 器与工件间隙不匀产生的温度不匀影响越小。早期的中频加热炉淬火对转速范围一般设定 为60〜300r/min,有些机床是有级变速，有些机床则采用无级变速，用户可以任意 选择。然而有些机床因特定条件，转速特低。如曲轴颈旋转淬火机，其主轴颈转速 常用60r/min,而连杆颈转速则选用30r/min,这是由于连杆颈在中频加热炉淬火上通过摆 动机构（四相连杆机构）产生转动，如转速太快，半环感应器不能稳定地跨到轴 颈上随动，所以只能采用30r/min的低速旋转，此种转速对轴颈加热而言是不合适 的，主轴颈采用60r/min是由于采用双速电机，有一种论点，认为转速的选取，应该以工件加热周期来考虑，工件在一个加热 周期中，旋转应不低于10次，就能保证工件圆周上温度均匀。据此计算，一般工 件感应加热时间常在5〜10s之间，如果5s转1。转，则为120r/min, 10s转10转, 则转速为60r/min。

随着感应加热速度的发展，对于同步双频加热齿轮，齿轮的加热周期已缩短到 0.1〜0.2s。因此，其工件转速要求在不断增加，有些中频加热炉淬火主轴的最大转速已 达到1600r/min_o目前，中频加热炉淬火的转速达到600r/min的已不多见。另外，工件转 速与冷却也有密切关系，对齿轮、花键轴而言，淬火冷却常采用喷液方式，工件转速太快，淬火液对齿的一侧冷却不足。因此，中频加热炉淬火的转速还是以600r/min或300r/min作为上限。另外，要研发加热结束后工件能及时降速的机械或电器部件， 使工件既能快速旋转达到均匀加热的目的，又能慢速旋转，以达到均匀冷却齿轮类 工件的要求。

How to choose the rotation speed of the main center of induction heating furnace quenching?

Regarding the selection of the rotating speed when the quenched workpiece is heated, in terms of the uniformity of the heating of the workpiece, the faster the rotating speed, the smaller the influence of temperature unevenness due to the uneven gap between the inductor and the workpiece. The speed range of the early induction heating furnace quenching is generally set at 60~300r/min. Some machine tools have a stepless speed change, and some machine tools use a stepless speed change, which the user can choose arbitrarily. However, some machine tools have extremely low speed due to specific conditions. For example, the crankshaft journal rotary hardening machine, the main journal speed is usually 60r/min, and the connecting rod journal speed is 30r/min. This is because the connecting rod neck is produced by the swing mechanism (four-linked rod mechanism) during the quenching of the induction heating furnace If the rotation speed is too fast, the half-ring sensor cannot stably move across the journal, so it can only rotate at a low speed of 30r/min. This speed is not suitable for journal heating. The main journal uses 60r/min is due to the use of a two-speed motor. There is an argument that the choice of speed should be considered based on the heating cycle of the workpiece. The workpiece should be rotated no less than 10 times in a heating cycle to ensure uniform temperature on the circumference of the workpiece . Based on this calculation, the induction heating time of general workpieces is usually between 5 and 10s, if 5s turns to 1. If it rotates at 120r/min, if it rotates for 10s in 10s, it will rotate at 60r/min.

With the development of induction heating speed, for synchronous dual-frequency heating gears, the heating period of the gears has been shortened to 0.1~0.2s. Therefore, the requirements of the workpiece speed are increasing. The maximum speed of the quenching spindle of some  induction heating furnaces has reached 1600r/min. At present, it is rare that the quenching speed of the induction heating furnace reaches 600r/min. In addition, the rotation speed of the workpiece is also closely related to the cooling. For gears and spline shafts, the quenching cooling often adopts the spraying method. The rotation of the workpiece is too fast, and the quenching liquid is insufficient to cool one side of the tooth. Therefore, the quenching speed of the  induction heating furnace is still 600r/min or 300r/min as the upper limit. In addition, it is necessary to develop mechanical or electrical components that can reduce the speed of the workpiece in time after heating, so that the workpiece can rotate quickly to achieve uniform heating, and it can rotate slowly to achieve the requirement of uniform cooling of gear workpieces.