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M12 waterproof circular connector Research on thread torque control method

Time:2020-10-25 20:33:04 Hits: 309
Screw torque control method of M12 waterproof circular connector: the thread connection and its influencing factors are analyzed. Combined with the production practice, when the output torque of the four axle front and rear axle U-bolt tightening machine reaches the target value (the torque value is displayed on the main monitoring operation display screen), the torque of the nut can not meet the requirements of the process specification The difference between the dynamic torque and the static torque is tested and analyzed. The torque control value is obtained by statistical method. The concept of dynamic torque and static torque is introduced in the torque control process to establish the torque control method, which is applied to the product quality control process.



螺纹连接通过螺栓轴向预紧力连接两部分,这是机械产品中的共同连接模式。螺栓轴向预拧紧力对连接强度的直接影响,螺纹对抗松动和连接部之间的密封。稳定和适当的轴向预载是可靠连接的前提。在实际工作中,直接测量螺栓轴向夹紧力是不方便的,因此通常需要控制螺栓扭矩以获得适当的轴向夹紧力。


在工程车辆的前后轴和后轴和叶片的组装过程中,在确认连接部件,螺纹对和操作方法处于稳定状态的情况下,进行骑螺栓和螺母的预紧拧紧状态,电动紧固机用于拧紧待测螺母,然后通过数字显示扭矩扳手检测扭矩值。发现扭矩值不一致,不能满足过程规范的要求(如表1所示)。本文分析了问题,并提出了解决问题的方法。


Preconditions: 1. Process specified torque: 200N. M ~ 250N. M; 2. Setting torque of tightening machine: 250N. M


1,分析影响扭矩的因素


扭矩,摩擦和夹紧力之间的关系如图1所示:扭矩(m)=力(f)×臂(l)


根据扭矩和紧固技术的原理,图2中示出了扭矩,摩擦和夹紧力之间的关系。当螺栓在紧固期间拉伸时,它将在连接器上产生夹紧力。然而,在组装过程中,通过摩擦消耗90%的扭矩,并且仅将10%的扭矩转化为夹紧力。但在实际的装配过程中,无法测量夹紧力,难以检测,我们可以测量扭矩。


1.The influence of friction


通过计算:摩擦力的变化将导致连接器中夹紧力的40%变化。根据扭矩控制方法的分析,螺栓的轴向预紧力F与拧紧期间施加的紧固扭矩T成比例。由T = Kf表示,K是扭矩系数,其值主要由接触表面和螺纹之间的摩擦阻力决定。通常,k值约为0.2-0.4,有时它在0.1和0.5之间。因此,摩擦抗性的变化对扭矩产生很大影响。也就是说,当用相同的设定的扭矩值拧紧两个具有不同摩擦阻的连接器时,获得的螺栓扭矩大大不同,这可以达到两倍。利用不同的螺母状态,摩擦力不同,并且扭矩相应地变化。


2.连接模式


The connection mode is divided into hard connection, neutral connection and soft connection. According to QC / t518-2007 automotive threaded fasteners tightening torque specification requirements, grade 8.8 M14 × 1.5 The torque of the bolt is 146n. M ~ 206n. M. the static torque is 156n. M ~ 248n. M for hard connection, 141n. M ~ 247n. M for neutral connection and 108n. M ~ 262n. M for soft connection. The influence torque is ± 27.2%. In the process of tightening, the greater the deformation of the connector and the connected part in the axial direction of the bolt, the more "soft" the connection is; on the contrary, the more "hard" the tightening angle of the hard connection is less than 30 ° and the tightening angle of the soft connection is greater than 720 ° in the actual bending, but most of the connections are neutral connections, and the tightening angle is between 30 ° and 720 °. The influence of connection mode on torque is shown in Fig. 3



3,扭矩控制


1.静态扭矩值的正确评价is to collect 100 actual torque measurement values, and then calculate the standard deviation s with the help of statistical analysis method. According to the actual assembly situation, ± 2S or ± 3S is taken as the upper and lower bending limit of the control range, which is used to inspect and evaluate the tightening effect of bolt connection, and the measured static torque value must be within the set upper and lower bending limit. However, in the process of formulating the static torque value, due to the limitation of personnel and time, it is impossible for each fastening bolt to be measured 100 times. In order to obtain the correct torque and quickly and conveniently formulate the static torque value, the following empirical formula can be used (T: middle value in the figure; t: the middle value in the figure; t: the middle value in the figure);



答:计算静态检查中间值SO和静态公差B,并且根据公差变化的要求确定静态扭矩值≤35%和中值变化≤15%≤15%,在一般的全局静态扭矩规格释放和更新过程(NOA No. GGAS-345)。


2.绘制动态扭矩和静态扭矩的比较表,用于控制范围和实际生产检查,如表3所示。



3.制定静态扭矩测试规范。


4。结论


叶片春骑螺栓的紧固是汽车组装扭矩控制的关键点之一。合格的扭矩控制对组装质量非常重要,但有许多影响扭矩的因素。在实际生产中,特别是在批量生产过程中,扭矩控制是复杂的工作。通过分析扭矩的影响,发现动态扭矩与静态扭矩之间的关系,并应用于公司实现质量控制QCOS,解决了螺栓拧紧扭矩控制方法的实际生产,提高了产品质量的稳定性。



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