The ball screw is composed of a screw, a nut, a ball and a ball returning device, and its main function is to convert rotary motion into linear motion. It is widely used in precision equipment, especially in numerical control equipment. The pulse signal sent by the control system controls the rotation of the servo motor, and then the precision ball screw converts the rotation motion of the servo motor into the linear motion of the workbench, so as to realize the machining trajectory control of the workpiece. Therefore, the assembly process and precision detection are very strict, and the technical requirements for assembly workers are also high.

一、故障现象

1、 Fault phenomenon

某数控设备有限公司在数控车床精密滚珠丝杠装配后进行静态精度检查时合格,但在试车后或使用一段时间后出现精密滚珠丝杠的轴向跳动严重超差,影响了机床的加工精度,设备返修率为43%,给企业带来巨大的经济损失和声誉损失。

A numerical control equipment Co., Ltd. passed the static accuracy inspection after the assembly of the precision ball screw of the numerical control lathe. However, the axial runout of the precision ball screw was seriously out of tolerance after the test run or after a period of use, which affected the machining accuracy of the machine tool. The equipment repair rate was 43%, bringing huge economic losses and reputation losses to the enterprise.

二、故障原因分析

2、 Fault cause analysis

1.精密滚珠丝杠精度达不到要求

1. The precision of precision ball screw cannot meet the requirements

滚珠丝杠在入库时已进行了精度检验,可排除本身的质量问题。但细长轴类零件(机床丝杆等)在保管时应该采用垂直放置,以免受重力变形影响精度。该滚珠丝杠采专用包装箱垂直放置,在装配后的静态检查合格,因此可以排除此项。

The ball screw has been inspected for accuracy when it is put into storage, which can eliminate its own quality problems. However, the slender shaft parts (machine tool screw rods, etc.) should be placed vertically during storage to avoid the influence of gravity deformation on the accuracy. The ball screw is vertically placed in a special packing box. After assembly, the static inspection is qualified, so this item can be excluded.

2.装配不当损坏了丝杠的精度

2. Improper assembly damages the accuracy of the lead screw

通过了解,装配工人对精密滚珠丝杠组件熟悉的,装配时也是格外小心,完全按装配工艺进行的,因此也排除了这种可能。

Through understanding, the assembly workers are familiar with the precision ball screw components, and they are also very careful when assembling. They are completely carried out according to the assembly process, so this possibility is also excluded.

3.机床行程超程,工作台发生碰撞,导致精度损坏

3. The travel of the machine tool is out of range, and the workbench collides, resulting in accuracy damage

操作机床时发生超程,容易导致机床碰撞而引起的。但经了解机床的行程限位开关没有问题,用户也没有这方面的意见反馈。

Overtravel occurs when operating the machine tool, which is easily caused by collision of the machine tool. However, it is understood that there is no problem with the travel limit switch of the machine tool, and the user has no feedback on this aspect.

4.检测方法不正确,导致精度超差

4. The detection method is incorrect, resulting in out of tolerance of accuracy

检验员采用千分表配合磁力表座,以工作台直线导轨滑座为检测基准进行检测,检测方法及检测基准也符合要求。

The inspector uses a dial indicator to cooperate with the magnetic meter base, and uses the linear guide rail slide of the workbench as the detection benchmark. The detection method and the detection benchmark also meet the requirements.

5.装配工艺不正确,造成装配误差

5. Incorrect assembly process, resulting in assembly error

原装配步骤是:先装好直线导轨,以直线导轨的滑座为基准校正丝杠,再以丝杠两端支承座安装孔配作固定螺纹孔。用螺钉固定丝杠后,用磁力表座将千分表固定在直线导轨滑座上,测量丝杠、侧母线和丝杠径向跳动量,保证丝杠的平行度及跳动量在要求范围内。重新配作支承座定位锥销,装好锥销后再复检一次。装配各步骤采用的处理方法基本正确,检测基准与工艺基准也相符,检测量具精度也能满足要求,被测要素也正确。整个装配过程没有问题,但通过在现场观察,发现装配工艺中仍存在以下问题:

The original matching steps are as follows: first install the linear guide rail, calibrate the lead screw based on the sliding seat of the linear guide rail, and then use the mounting holes of the bearing seats at both ends of the lead screw as fixed screw holes. After fixing the lead screw with screws, fix the dial indicator on the slide seat of the linear guide rail with the magnetic gauge base, measure the radial runout of the lead screw, the side bus bar and the lead screw, and ensure that the parallelism and runout of the lead screw are within the required range. Refit the positioning cone pin of the support seat, and recheck it after installing the cone pin. The processing methods adopted in each step of assembly are basically correct, and the test datum is consistent with the process datum. The accuracy of the measuring tools can meet the requirements, and the measured elements are also correct. There are no problems in the whole assembly process, but through on-site observation, it is found that the following problems still exist in the assembly process:

(1)使用手电钻铰孔时,由于铰削余量较大,振动较厉害,双手控制不稳,铰刀摆动过大,造成锥孔铰削后上大下小,锥度不是要求的1∶50。用涂色法进行检查,发现锥销与锥孔的接触部位不正确,位置靠近小头一端,不能保证良好的接触精度,受到交变应力与振动时容易松动,从而导致定位精度下降。

(1) When reaming with hand electric drill, the reaming allowance is large, the vibration is severe, the control of both hands is unstable, and the reamer swings too much, resulting in the reaming of the tapered hole being large up and small down, and the taper is not required to be 1:50. It is found that the contact part between the taper pin and the taper hole is incorrect, and the position is close to the end of the small head, which can not guarantee good contact accuracy. It is easy to loosen when subjected to alternating stress and vibration, resulting in a decrease in positioning accuracy.

(2)机铰后没有留精铰余量,也没有进行手工精铰。圆锥销的配合都是依靠配合面的过盈产生摩擦力来定位的。由于机铰后表面粗糙使实际过盈量减少,造成摩擦力不够,自锁性能下降,当受到交变应力与振动时容易松脱,从而导致定位精度下降。

(2) There is no allowance for fine hinge after mechanical hinge and no manual fine hinge. The fitting of conical pin is located by the friction force generated by the interference of the fitting surface. Due to the rough surface after the mechanical hinge, the actual interference amount is reduced, resulting in insufficient friction, and the self-locking performance is reduced. When it is subjected to alternating stress and vibration, it is easy to loose, resulting in the reduction of positioning accuracy.

(3)铰孔时孔径控制不严,铰削过程中没用锥销试配,装配时用铜棒轻轻敲入即可。由于不能保证足够的过盈量,装配后的摩擦力过小;受负荷及振动时易造成锥销松动,失去定位作用,导致工作台运动精度差。

(3) The hole diameter is not strictly controlled during reaming. During reaming, no taper pin is used for trial fitting. During assembly, a copper rod can be used to gently knock in. The friction force after assembly is too small due to insufficient interference; Under load and vibration, it is easy to cause the taper pin to loosen and lose the positioning function, resulting in poor movement accuracy of the workbench.

(4)在钻孔铰孔等过程中,没有进行防尘处理。虽然丝杠副带有防尘圈,但铸铁粉尘非常细小,且极易粘附在丝杠表面。如有少量进入丝杠副传动面,粉尘的研磨作用会加剧丝杠副的磨损,导致丝杠精度下降,降低使用寿命。

(4) In the process of drilling and reaming, no dust-proof treatment was carried out. Although the lead screw pair is provided with a dust ring, the cast iron dust is very small and easily adheres to the surface of the lead screw. If a small amount of dust enters the transmission surface of the lead screw pair, the grinding effect of dust will aggravate the wear of the lead screw pair, resulting in the reduction of the accuracy of the lead screw and the reduction of the service life.

三、故障处理办法

3、 Troubleshooting

1.使用机铰粗铰后必须留出精铰余量,再手工精铰

1. After the mechanical hinge is used, the fine hinge allowance must be reserved before manual fine hinge

这个方法可以纠正机铰后的锥度误差,降低孔壁的表面粗糙度值,提高配合面的接触精度,保证足够的摩擦力矩。

This method can correct the taper error after reaming, reduce the surface roughness of the hole wall, improve the contact accuracy of the mating surface, and ensure sufficient friction torque.

2.在铰孔时应及时用锥销试配

2. During reaming, taper pins shall be used for trial fitting in time

目的是方便控制铰孔孔径。当锥销能用手插入销长的80%～85%左右时孔径才为合格;清理铁屑后,应在锥销上涂机油后再用铜棒打入与工件表面平齐,以保证足够的摩擦力矩,防止在使用中受载荷而松动。

The purpose is to conveniently control the reaming hole diameter. The hole diameter is qualified when the taper pin can be manually inserted into about 80% ~ 85% of the pin length; After the iron scraps are cleaned, the taper pin shall be coated with oil and then driven with a copper rod until it is flush with the surface of the workpiece, so as to ensure sufficient friction torque and prevent loosening due to load during use.

3.做好丝杠表面的防尘处理

3. Conduct dust-proof treatment on the surface of the lead screw

在钻孔、铰孔及攻螺纹过程中,应作好丝杠表面的防尘处理。用清洁的布包裹住丝杠的外露部分,防止粉尘进入丝杠副传动面,以延长精密元件的使用寿命,提高装配精度。

In the process of drilling, reaming and tapping, the dust-proof treatment of the surface of the lead screw shall be done well. Wrap the exposed part of the lead screw with clean cloth to prevent dust from entering the drive surface of the lead screw pair, so as to extend the service life of the precision components and improve the assembly accuracy.

在制造汽车、手机、电脑等的机床及工业机器人、液晶显示屏及半导体生产设备、生产塑料零部件的注塑机等领域，滚珠丝杠作为产品制造厂设备中的核心零件，发挥这重要作用。

In the fields of machine tools and industrial robots for manufacturing automobiles, mobile phones, computers, etc., liquid crystal displays and semiconductor production equipment, and injection molding machines for producing plastic parts, ball screws play an important role as the core parts in the equipment of product manufacturers.

正确的安装丝杠能有效地提升设备的运转精度、延长使用寿命。

The correct installation of the lead screw can effectively improve the operation accuracy and prolong the service life of the equipment.

以上就是为大家介绍的有关导轨丝杠的详细的介绍,希望对您有所帮助.如果您有什么疑问的话,欢迎联系我们.我们将以的态度,为您提供服http://www.jngongrun.com

The above is the detailed introduction of the guide rail lead screw for you. I hope it will help you. If you have any questions, please contact us. We will provide services for you with a professional attitude http://www.jngongrun.com