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(dòng)零件，起周向固定零件的作用以傳遞旋轉(zhuǎn)運(yùn)動(dòng)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(dòng)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.

楔鍵聯(lián)接：鍵的上下兩表面是工作面，鍵的上表面和輪轂鍵槽底面均有1∶100的斜度，裝配后，鍵即楔緊在軸和輪轂的鍵槽里，工作表面產(chǎn)生很大預(yù)緊力。

Wedge key connection: the upper and lower two surfaces of the key are the working faces. The upper surface of the key and the bottom of the hub keyway have 1 to 100 slope. After assembly, the key is wedged tightly in the keyway of the shaft and hub, and the working surface has a large pre tightening force.

機(jī)用虎鉗的結(jié)構(gòu)及原理。機(jī)用虎鉗是機(jī)械加工中常用的裝夾機(jī)構(gòu)，其結(jié)構(gòu)如圖1所示。其主要工作原理：轉(zhuǎn)動(dòng)方頭帶動(dòng)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(yùn)動(dòng)的絲杠帶動(dòng)與之聯(lián)接的活動(dòng)座沿絲杠軸線方向來回移動(dòng)。

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.