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The connection between the motor and the lead screw of the CNC machine tool

The feed drive of CNC machining tools has high requirements on position accuracy (precision), fast response performance, and speed adjustment range. In numerical control processing, the control system sends out instructions to make the cutter perform various movements that meet the requirements, and expresses the processing of technical requirements and processing requirements such as the shape and size of the workpiece in the form of numbers and letters. It generally refers to the process of processing parts on CNC machine tools. In order to improve production automation, shorten programming time and reduce CNC machining costs, a series of advanced CNC machining technologies have also been developed and used in the aerospace industry. CNC machining CNC is also known as computer gong, CNCCH or CNC machine tool. It is actually a name from Hong Kong, which greatly reduces the number of tooling. CNC machining of parts with complex shapes does not require complicated tooling. CNC machining is a new type of processing technology and the main work It is to compile the processing program, that is, to convert the original manual to computer programming. If you want to change the shape and size of the part, you only need to modify the part processing program, which is suitable for new product development and modification. There are three main types of motors used in CNC machining machine tools to achieve feed drive: stepper motors, DC servo motors, and AC servo motors. At present, stepper motors are only used for economical numerical control machine tools (attribute: automatic machine tools), DC servo motors are widely used in China (extensive), and AC servo motors are being replaced by ideal step components (step by step) One substance replaces another (mostly the strong replace the weak)) DC servo motor. When the feed system of the CNC machine tool uses different transmission elements, its transmission structure is different. There are three main types of connection between the motor and the lead screw, as shown in Figure 69.

1. Gear transmission mode

The connection form of the motor and the screw, the CNC machining machine generally uses a gear transmission pair in the feed transmission device to achieve a certain speed reduction ratio. Since the gear may not meet the ideal tooth surface requirements in manufacturing, there is always a certain error. A pair of meshing gears must have a certain backlash to work properly, but the backlash will cause reverse transmission clearance. For closed-loop systems, the backlash will affect the stability of the system (explanation: stable and stable; no change) (The stability of). Therefore, gear transmission pairs often use an anti-backlash mechanism to minimize backlash.

2. Transmission form of synchronous belt wheel

The structure of this type of connection is relatively simple. In numerical control processing, the control system sends out instructions to make the cutter perform various movements that meet the requirements, and expresses the processing of technical requirements and processing requirements such as the shape and size of the workpiece in the form of numbers and letters. It generally refers to the process of processing parts on CNC machine tools. In order to improve production automation, shorten programming time and reduce CNC machining costs, a series of advanced CNC machining technologies have also been developed and used in the aerospace industry. Synchronous belt transmission combines the advantages of belt transmission and chain transmission, which can avoid the vibration and noise caused by gear transmission, but can only be applied to the occasions with low torque characteristics, the center distance requirements are strict during installation, and the manufacturing process of belt and pulley complex.

3. Coupling (Coupling) transmission form

Normally, a conical ring keyless connection or a high-precision (accuracy) cross coupling (Coupling) connection is used between the motor shaft and the screw, so that the feed transmission system has a higher transmission accuracy (accuracy) and transmission rigidity And greatly simplify the transmission structure. This type of connection is commonly used in the feed drive of machining centers and CNC machine tools (attributes: automated machine tools) with high accuracy (precision).

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