螺杆压缩机转子成形砂轮刃形计算

Calculation Method for Edge Shape of Forming Wheel for Screw Rotors Machining

针对给出任意转子型线时转子齿面加工的成形砂轮刃形设计,利用螺杆转子加工过程中转子和砂轮的相对位置关系,通过对转子型线坐标系的旋转变换,建立空间转子坐标系和成形砂轮坐标系之间的几何映射关系;基于啮合原理,建立转子齿面与成形砂轮的接触线方程,并给出解析和离散两种转子型线表达方式的刃形求解方法。在此基础上,根据转子砂轮之间的设计间隙,通过对接触线沿转子齿面法向进行偏置,获得了修整后的砂轮等距齿面刃形,避免了传统修整方法导致的法向齿间间隙不均等问题。加工结果表明,该方法能够满足螺杆转子的加工精度要求,是一种有效的螺杆转子齿面成形砂轮的刃形设计方法,并可推广应用于其他螺旋面成形砂轮或盘形铣刀的刃形设计。

A design method of forming wheel edge shape for screw rotors machining is presented when arbitrary rotor profile is given.According to the position relationship of the rotor and the forming wheel during machining process,the geometric mapping of the above two coordinate systems is established by rotation transformation of the rotor profile coordinate system.The contact line equation between the rotor tooth surface and the forming wheel revolving surface is derived based on the meshing theory.On this basis,the calculation method for theoretical edge shape of forming wheel is proposed,which is applicable to both analytical and discrete forms of the rotor profile.The corrected edge shape is gained by offsetting the contact line along the normal vector direction with the given inter-lobe clearance,and the defect of unequal normal inter-lobe clearance in the traditional method can be avoided.The machining results show that the proposed method can satisfy the screw rotor accuracy,which is an effective method to get forming wheel edge shape for screw rotor,and the method also can be popularized to edge shape design of other helicoids forming wheel or disc milling cutter.