The chuck is a mechanical device used to clamp the workpiece on the machine tool. The chuck is a machine tool accessory that clamps and positions the workpiece by using the radial movement of the movable claws evenly distributed on the chuck body.
a chuck is generally composed of a chuck body, a movable jaw and a jaw driving mechanism. The minimum diameter of the chuck body is 65 mm, and the maximum diameter is 15 mm, and there is a through hole in the center to pass through the workpiece or bar; The back has a cylindrical or short conical structure, which is connected with the end of the machine tool spindle directly or through a flange. Chuck is usually installed on lathes, cylindrical grinders and internal grinders, and can also be used in milling machines and drilling machines with various indexing devices.
classification
chucks can be divided into manual chucks and power chucks according to the different power used to drive the jaws.
1. Manual chuck: it is a general accessory, and commonly used are three-jaw chuck with automatic centering and four-jaw chuck with each jaw moving independently. The three-jaw chuck is driven by a small bevel gear and a large bevel gear. There is Archimedes spiral groove on the back of the big bevel gear, which is engaged with three claws.
Therefore, by turning the pinion with a wrench, the three jaws can move radially at the same time, realizing automatic centering and clamping, which is suitable for clamping circular, regular triangular or regular hexagonal workpieces. The bottom surface of each jaw of a four-jaw chuck (four-jaw chuck in Figure 2) has an internal thread connected with a screw, and each screw can be rotated by a wrench to make the connected jaws move radially, which is suitable for clamping quadrilateral or asymmetrical workpieces.
2. power chuck: it belongs to self-centering chuck, and can be combined with different power devices (air cylinder, oil cylinder or motor) to form pneumatic chuck, hydraulic chuck or electric chuck. The air cylinder or oil cylinder is installed at the rear end of the machine tool spindle, and the wedge sleeve in the chuck at the front end of the spindle is pushed and pulled by a pull rod or a pull tube passing through the spindle hole, and the three jaws move radially at the same time by the axial advance and retreat of the wedge sleeve. The wedge sleeve power chuck in the figure is a wedge sleeve power chuck. This chuck has quick action and small jaw movement, and is suitable for mass production.