種是摩擦防松。這是應(yīng)用更廣的一種防松方式,這種方式在螺紋副之間產(chǎn)生一不隨外力變化的正壓力,以產(chǎn)生一可以阻止螺紋副相對(duì)轉(zhuǎn)動(dòng)的摩擦力。這種正壓力可通過(guò)軸向或同時(shí)兩向壓緊螺紋副來(lái)實(shí)現(xiàn)。如采用彈性墊圈、鋼筋連接套筒、自鎖螺母和尼龍嵌件鎖緊螺母等。這種防松方式對(duì)于螺母的拆卸比較方便,但在沖擊、振動(dòng)和變載荷的情況,開始螺栓會(huì)因松弛導(dǎo)致預(yù)緊力下降,隨著振動(dòng)次數(shù)的增加,損失的預(yù)緊力緩慢地增多,更終將會(huì)導(dǎo)致螺母松脫、螺紋聯(lián)接失效。
The first is friction and anti loosening. This is the most widely used anti loosening method, which produces a positive pressure between the thread pairs that does not change with the external force to produce a friction force that can prevent the relative rotation of the thread pairs. The positive pressure can be achieved by pressing the thread pair axially or simultaneously. For example, elastic washer, steel connecting sleeve, self-locking nut and nylon insert lock nut are used. This anti loosening method is convenient for nut disassembly, but in the case of impact, vibration and variable load, the pre tightening force of the bolt will decrease at the beginning due to relaxation. With the increase of vibration times, the lost pre tightening force will slowly increase, which will eventually lead to nut loosening and thread coupling failure.
第二種方式是機(jī)械防松。是用止動(dòng)件直接限制螺紋副的相對(duì)轉(zhuǎn)動(dòng)。如采用開口銷、串連鋼絲和止動(dòng)墊圈等。由于止動(dòng)件沒有預(yù)緊力,螺母松退到止動(dòng)位置時(shí)防松止動(dòng)件才能起作用,因此,這種方式實(shí)際上不防松而是防落。
The second is mechanical locking. It is to directly limit the relative rotation of the thread pair with the stopper. Such as the use of cotter pin, steel wire and stop washer. Since the stop has no pre tightening force, the stop can only work when the nut is loosened and retreated to the stop position. Therefore, this method does not prevent loosening but falling off.
第三種方式是鉚沖防松。在擰緊后采用沖點(diǎn)、焊接、粘接等方法,使螺紋副失去運(yùn)動(dòng)副特性而連接成為不可拆連接。這種方式的缺點(diǎn)是栓桿只能使用一次,且拆卸十分困難,必須破壞螺栓副方可拆卸。
The third way is riveting and punching. After tightening, punching, welding, bonding and other methods are used to make the thread pair lose the characteristics of the moving pair and become a non detachable connection. The disadvantage of this method is that the bolt rod can only be used once, and it is very difficult to disassemble, so the bolt pair must be destroyed before disassembly.
第四種方式是結(jié)構(gòu)防松。是利用螺紋副自身結(jié)構(gòu),即唐氏螺紋防松方式。
The fourth way is to prevent the structure from loosing. It uses the thread pair's own structure, i.e. down thread locking mode.