Screw is a commonly used transmission component in engineering machinery and precision machinery. The main structure of a screw is composed of a screw and a nut, and its main function is to convert rotational motion into linear motion or torque into axial repeated force. The principle is that when the lead screw is used as the driving body, the nut converts into linear motion according to the corresponding specifications of the lead with the rotation angle of the lead screw. The passive workpiece can be connected through a nut seat and nut to achieve corresponding linear motion. Roller screw has the characteristics of high transmission efficiency and precision, and has basically replaced traditional trapezoidal screw in most scenarios. The commonly used thread screws can be divided into triangular thread screws, trapezoidal thread screws, ball screws, and planetary roller screws.

（1） 三角螺纹丝杠：三角牙丝杠其牙型类似于三角形顶部为尖状，是各类简易螺 丝常用的牙型，其加工便当、制作简略，市场上有较多标准件出售。 （2） 梯形螺纹丝杠：梯形螺纹丝杠的牙型为等腰梯形，上窄下宽。加工相对简略， 可以依据牙的深浅来调理螺母和丝杆的松紧度。表里螺纹以锥面贴紧不易松 动，工艺较好，牙根强度高，对中性好。梯形丝杆的传动效率大约为26-46%。

(1) Triangle thread screw: Triangle thread screw has a tooth shape similar to the pointed top of a triangle, which is commonly used for various simple screws. Its processing is convenient and its production is simple, and there are many standard parts available for sale in the market. (2) Trapezoidal thread screw: The tooth shape of the trapezoidal thread screw is an isosceles trapezoid, with a narrow top and a wide bottom. The processing is relatively simple, and the tightness of the nut and screw can be adjusted based on the depth of the teeth. The thread inside the watch is tightly attached with a conical surface, which is not easy to loosen. The process is good, the root strength is high, and it is good for neutrality. The transmission efficiency of the trapezoidal screw is approximately 26-46%.

（3） 滚珠螺纹丝杠：其丝杆和螺母之间选用滚珠翻滚的方式来进行传动，可通过 替换滚珠的方式来丝杠和螺母之间的空地。故传动功率高，精度高，静 音作用好。

(3) Ball screw: The ball rolling method is used for transmission between the screw and nut, and the vacant space between the screw and nut can be eliminated by replacing the ball. Therefore, the transmission power is high, the accuracy is high, and the mute effect is good.

现已广泛的应用于各种自动化设备，机床等。一般环境下已大部 分替代了梯形丝杠，其传动效率约为90-96%。

It has been widely used in various automation equipment, machine tools, etc. In general, trapezoidal screws have been mostly replaced, with a transmission efficiency of approximately 90-96%.

（4） 行星滚柱丝杠：标准行星滚柱丝杠主要由丝杠、滚柱、螺母、直齿、内齿圈、 滚柱保持架和弹簧挡圈等组成，其综合了行星齿轮传动、谐波齿轮传动、滚 珠丝杆、滚针轴承等机构的优点。通过在主丝杠周围布置若干行星螺纹滚柱, 大幅增加丝杠传动过程的接触面和受力面,从而具备了“高承载、率、高 精度、高可靠性”等优点。在丝杠转速、接触角与螺旋升角较为理想的状态 下，行星滚柱丝杠传动效率可达到90%以上。

(4) Planetary roller screw: The standard planetary roller screw is mainly composed of screw, roller, nut, straight tooth, inner gear ring, roller cage, and spring retainer, which combines the advantages of planetary gear transmission, harmonic gear transmission, ball screw, needle roller bearing and other mechanisms. By arranging several planetary thread rollers around the main lead screw, the contact surface and stress surface of the lead screw transmission process are greatly increased, thus possessing the advantages of "high load-bearing, high efficiency, high precision, and high reliability". Under ideal conditions of screw speed, contact angle, and helix angle, the planetary roller screw transmission efficiency can reach over 90%.

其中三角螺纹丝杠与梯形丝杠生产技术相对较为简单，已基本实现完全国产化。滚 珠丝杠发展起步相对较早，低端滚珠丝杠国产化率已达到相对较高水平。但目前国 内在中滚珠丝杠及行星滚柱丝杠的国产化率相对较低，未来发展空间较大。

The production technology of triangular thread screw and trapezoidal screw is relatively simple and has basically achieved complete localization. The development of ball screws started relatively early, and the localization rate of low-end ball screws has reached a relatively high level. However, at present, the localization rate of high-end ball screws and planetary roller screws in China is relatively low, and there is greater room for future development.

直线导轨结构简单稳定，大量运用于机械加工过程中。直线导轨在机械加工中比较 常用，其由钢珠在滑块跟导轨之间无限滚动循环， 从而使负载平台沿着导轨轻易的 高精度线性运动。依按摩擦性质而定，直线运动导轨可以分为滑动摩擦导轨、滚动 摩擦导轨、弹性摩擦导轨、流体摩擦导轨等种类。直线导轨下游应用广泛，主要包括 数控机床、医疗器械、自动化生产线等领域。

The linear guide rail structure is simple and stable, and is widely used in mechanical processing. Linear guide rails are commonly used in mechanical processing, where steel balls infinitely roll and circulate between the slider and the guide rail, allowing the load platform to easily move in high-precision linear motion along the guide rail. According to the friction properties, linear motion guides can be divided into sliding friction guides, rolling friction guides, elastic friction guides, fluid friction guides, and other types. Linear guide rails are widely used downstream, mainly in fields such as CNC machine tools, medical devices, and automated production lines.