花键联接由内花键和外花键组成。内、外花键均为多齿零件，在内圆柱表面上的花键为内花键，在外圆柱表面上的花键为外花键。显然，花键联接是平键联接在数目上的发展。

The connection of the spline is made up of the inner and outer spline. The inner and outer spline are multi tooth parts, and the spline on the surface of the inner cylinder is the inner spline, and the spline on the outer cylindrical surface is the outer spline. It is that the spline connection is the development of the number of flat bond connecti.

渐开线花键的定心方式为齿形定心。受载时齿上有径向力，能起自动定心作用，有利于各齿受力均匀，强度高，寿命长。用于载荷较大，定心精度要求较高以及尺寸较大的联接，如航空发动机、燃气轮机、汽车等。压力角45°的花键多用于轻载、小直径和薄型零件的联接。

The involute spline is centering in the shape of the tooth. The tooth has radial force on the tooth, and it can play the role of automatic centering, which is beneficial to the uniform force of each tooth, high strength and long life. It is used for large load, high precision and large size connection, such as aero engine, gas turbine, automobile and so on. The spline with a pressure angle of 45 degrees is used for the connection of light, ***all diameter and thin parts.

胜过机用虎钳的柔性虎钳，在装夹中能有效防止工件的翻转、倾斜，克服了机用虎钳因配合间隙大导致工件受力不均、加工发颤等现象；解决了现有轻型、精密工件加工时装夹不可靠的问题。

Flexible than vice machine vise, the clamping can effectively prevent the workpiece turning and tilt, overcome the machine vise for clearance to workpiece uneven stress, etc. to solve the phenomenon of processing tremble; the existing light and precision workpiece clamping reliability of the fashion。

机用虎钳的结构及原理。机用虎钳是机械加工中常用的装夹机构，其结构如图1所示。其主要工作原理：转动方头带动丝杠，在螺母（通过紧固螺钉固定在虎钳体上）的作用下，做螺旋运动的丝杠带动与之联接的活动座沿丝杠轴线方向来回移动。

The structure and principle of machine vise. Machine vise is a common clamping mechani*** in mechanical processing. Its structure is shown in Figure 1. The main principle: rotation of the lead screw nut in the square, (fixed in the vise body through a fastening screw) under the action of moving spirally driven screw connected with the movable seat to move back and forth along the screw axis.