At present, the research of constant torque electric wrench mostly focuses on the digital display constant torque electric wrench with both constant value and overload failure function. It is very popular with users with the humanized LCD window. Moreover, they all have the functions of torque value monitoring, peak setting and early warning. Some also have wireless transmission function to communicate with the equipped wireless transmission terminal, and the terminal records and manages data.

从传统的指针式扭矩扳手到现在的具有多种功能的数显定扭矩电动扳手伴随着科技的发展实现了质的飞跃。现有的定扭矩电动扳手具有以下优点:①技术成熟、性能稳定;②操作界面人性化;③数据处理功能强等。

From the traditional pointer torque wrench to the digital display fixed torque electric wrench with multiple functions, it has achieved a qualitative leap with the development of science and technology. The existing constant torque electric wrench has the following advantages: ① mature technology and stable performance; ② Humanized operation interface; ③ Strong data processing function, etc.

定扭矩电动扳手存在的不足：

Shortcomings of constant torque electric wrench:

（1）系统组件多操作复杂

(1) Multiple system components and complex operation

文献《指针式扭矩扳手在施工中的应用》中提出了一种智能扭矩扳手系统包含电子标签，扭矩扳手，信息管理软件等，通过一系列的智能芯片完成所需功能。使用该扳手系统时,需要同时启动计算机，并对螺栓信息进行编号，信息录人管理软件，制作电子标签贴在相应的螺栓上。准备工作完毕后才能发挥扭矩扳手的功能，使用效率比较低，操作比较复杂。同类的扭矩扳手均存在结构复杂的问题。

In the document "Application of pointer torque wrench in construction", an intelligent torque wrench system is proposed, which includes electronic label, torque wrench, information management software, etc. the required functions are completed through a series of intelligent chips. When using the wrench system, it is necessary to start the computer at the same time, number the bolt information, record the information into the management software, make an electronic label and stick it on the corresponding bolt. The function of the torque wrench can only be brought into play after the preparation. The use efficiency is relatively low and the operation is relatively complex. Similar torque wrenches have the problem of complex structure.

（2）精度和难两全

(2) Accuracy and price are difficult

目前市场上的定扭矩电动扳手存在着精度和难两全的困境，精度较高的扳手通常是数显式定扭矩电动扳手，进口产品居多，普遍较高。较低的多为结构简单的指针式扭矩扳手，其精度低，难以满足使用要求。这也是扭矩扳手在相关领域应用不够广泛的原因之一。

At present, the constant torque electric wrench in the market has the dilemma of accuracy and price. The wrench with higher accuracy is usually digital display constant torque electric wrench, most of which are imported products, and the price is generally high. Most of the low price are pointer torque wrenches with simple structure, which have low precision and are difficult to meet the use requirements. This is also one of the reasons why torque wrenches are not widely used in related fields.

（3）智能化程度低

(3) Low intelligence

现有的定扭矩电动扳手都具有施加和监控扭矩值的功能,但是对于规格不同的螺栓施加多大的扭矩值仍需要人工设定。针对不同螺栓的预紧扭矩值的大小需要查询相关手册或者运用公式计算得知。目前只有一些特殊的行业的产品会附带螺栓预紧力的相关资料。常用的普通螺栓的预紧力具体数值仍然靠经验来确定,这也是阻碍定扭矩电动扳手应用的原因之一。

The existing constant torque electric wrenches have the function of applying and monitoring torque value, but the torque value applied to bolts with different specifications still needs to be set manually. For the pre tightening torque values of different bolts, you need to consult relevant manuals or use formulas to calculate. At present, only some products of special industries will be attached with relevant data of bolt preload. The specific value of preload of common bolts still depends on experience, which is also one of the reasons that hinder the application of constant torque electric wrench.