鍵是一種標(biāo)準(zhǔn)件，通常用于聯(lián)接軸與軸上旋轉(zhuǎn)零件與擺動零件，起周向固定零件的作用以傳遞旋轉(zhuǎn)運動和扭矩，楔鍵還可以起單向軸向固定零件。而導(dǎo)鍵、滑鍵、花鍵還可用作軸上移動的導(dǎo)向裝置。 根據(jù)鍵的結(jié)構(gòu)形式，鍵聯(lián)接可分為平鍵聯(lián)接、半圓鍵聯(lián)接、楔鍵聯(lián)接和切向鍵聯(lián)接等幾類。

The key is a standard part, which is usually used to connect the rotating parts and swing parts of the shaft and the axle to move the fixed parts to transmit rotary motion and torque, and the wedge key can also play a one-way axial fixation part. The guide, slippery key and the spline can also be used as a guiding device for moving on the axis. According to the structure of the key, key joins can be divided into a flat bond, a semicircle bond, a wedge bond and a tangent bond.

漸開線花鍵的定心方式為齒形定心。受載時齒上有徑向力，能起自動定心作用，有利于各齒受力均勻，強度高，壽命長。用于載荷較大，定心精度要求較高以及尺寸較大的聯(lián)接，如航空發(fā)動機、燃?xì)廨啓C、汽車等。壓力角45°的花鍵多用于輕載、小直徑和薄型零件的聯(lián)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, small diameter and thin parts.

機用虎鉗的結(jié)構(gòu)及原理。機用虎鉗是機械加工中常用的裝夾機構(gòu)，其結(jié)構(gòu)如圖1所示。其主要工作原理：轉(zhuǎn)動方頭帶動絲杠，在螺母（通過緊固螺釘固定在虎鉗體上）的作用下，做螺旋運動的絲杠帶動與之聯(lián)接的活動座沿絲杠軸線方向來回移動。

The structure and principle of machine vise. Machine vise is a common clamping mechanism 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.

裝夾后產(chǎn)品靠近活動鉗口附近容易上翹、抬起，多次裝夾一致性差。傳統(tǒng)機用虎鉗的螺旋副間隙較大，在使用中會產(chǎn)生較大振幅的振動；而活動座和虎鉗體之間的滑動接觸面較大，采用的間隙也較大。

After the clamping, the product is easy to  and lifted near the movable jaw, and the cistency of the clamping is poor many times. The spiral pair clearance of traditional machine vice is bigger, which will cause large amplitude vibration in use. The sliding contact between movable seat and jaw vice body is larger, and the gap used is bigger.