CN101856781B - A method of manufacturing a precision ball screw - Google Patents

A method for manufacturing a precision ball screw relates to the transmission technology in the technical field of machinery, and comprises the steps of adopting 38CrMoAl as a material, blanking, straightening, turning an excircle, tempering, repairing and grinding a central hole, grinding the excircle, grinding a screw thread of the screw by a thread grinder, milling a key groove or a square body, performing a bench work process, removing stress, grinding the central hole, nitriding glow ions, performing pulse electrochemical composite finishing, chamfering two ends of incomplete teeth for 1/4 circles, grinding threads and chamfering threads and processing the top end for 45 degrees. The invention can provide a precision ball screw with high hardness, high wear resistance, low roughness, low noise and long fatigue life.

一种精密滚珠丝杠制造方法A method of manufacturing a precision ball screw

技术领域： Technical field:

本发明涉及机械技术领域中的传动技术，特别是一种制造精密滚珠丝杠的技术领域。The invention relates to the transmission technology in the field of mechanical technology, in particular to the technical field of manufacturing precision ball screws.

背景技术 Background technique

滚珠丝杠副由滚珠丝杠、滚轴螺母和滚珠组成，是一种可将旋转运动转变为直线运动，或者将直线运动转变为旋转运动的部件。滚珠丝杠副具有传动效率高、工作寿命长、运动平稳、同步无爬行、无反向侧隙、摩擦特性优良、对环境适应性强等优点，是各类数控机床以及机电产品的关键传动副和定位元件，已广泛应用于各个传动领域，是国家列为重点振兴的“特定基础件产品”。The ball screw pair is composed of a ball screw, a roller nut and a ball, and is a component that can convert rotary motion into linear motion, or convert linear motion into rotary motion. The ball screw pair has the advantages of high transmission efficiency, long working life, smooth movement, no creeping synchronously, no reverse backlash, excellent friction characteristics, and strong adaptability to the environment. It is the key transmission pair of various CNC machine tools and electromechanical products. And positioning components have been widely used in various transmission fields, and are listed as "specific basic parts products" for national key revitalization.

目前国内制造滚珠丝杠的厂家，工艺路线多少都有些差别，产品质量也存在不少问题。一般的制造工艺步骤为：下料(材料绝大多数为GCr15)、校直、车外圆、中频淬火、回火、修研中心孔、磨外圆、螺纹磨磨削丝杠螺纹、铣键槽或方身、钳工工艺、去应力、半精密螺纹磨磨削丝杠螺纹、再去应力、研磨中心孔、精密外圆磨、精密螺纹磨磨削丝杠螺纹、倒两端不完整牙1/4圈、螺纹磨削倒角螺纹及顶端45°处理。At present, domestic ball screw manufacturers have somewhat different process routes, and there are many problems in product quality. The general manufacturing process steps are: blanking (most of the material is GCr15), straightening, turning the outer circle, intermediate frequency quenching, tempering, repairing the center hole, grinding the outer circle, thread grinding and grinding screw thread, milling keyway Or square body, fitter process, stress relief, semi-precision thread grinding, grinding screw thread, stress relief again, grinding center hole, precision cylindrical grinding, precision thread grinding grinding screw thread, incomplete teeth at both ends 1/ 4 turns, thread grinding chamfer thread and top 45° treatment.

以上工艺技术的缺陷：Defects of the above process technology:

1、中频淬火后，丝杠易弯曲，热处理变形较大；且回火时间短，易造成丝杠硬度不均匀，应力不易去除，去应力处理时间长，易留残余应力；1. After intermediate frequency quenching, the lead screw is easy to bend, and the heat treatment deformation is large; and the tempering time is short, it is easy to cause uneven hardness of the lead screw, the stress is not easy to remove, and the stress relief treatment takes a long time to leave residual stress;

2、磨削螺纹时，因为螺纹硬度高、磨削量大，造成磨削时间长、消耗材料多，易产生弯曲变形，同时由于磨削量大，温度高，易产生磨削裂纹和烧伤，造成产品报废；2. When grinding threads, due to the high thread hardness and large grinding amount, the grinding time is long, the material consumption is large, and bending deformation is easy to occur. At the same time, due to the large grinding amount and high temperature, grinding cracks and burns are easy to occur. cause the product to be scrapped;

3、精密磨削的螺纹滚道，因为机床本身的精度和加工调试水平，容易产生滚道波纹，表面质量差；3. For the precision ground thread raceway, due to the precision of the machine tool itself and the level of processing and debugging, it is easy to produce raceway ripples and poor surface quality;

4、丝杠硬度低(一般为HRC60左右)、耐磨性差、疲劳寿命短、噪音水平高(一般74db左右)；4. The screw has low hardness (generally around HRC60), poor wear resistance, short fatigue life, and high noise level (generally around 74db);

5、由于磨削后表面较粗糙，丝杠粗装配后要进行长时间跑和；5. Due to the rough surface after grinding, the lead screw needs to be run for a long time after rough assembly;

6、工序繁杂、加工周期长；6. The process is complicated and the processing cycle is long;

7、由于磨削工作量大，磨削时产生大量油雾，对环境造成污染，对工人健康造成损害。7. Due to the heavy grinding workload, a large amount of oil mist is generated during grinding, which pollutes the environment and damages the health of workers.

发明内容 Contents of the invention

本发明的目的是提供一种高硬度、高耐磨、低粗糙度、低噪音、长疲劳寿命的精密滚珠丝杠制造方法。The object of the present invention is to provide a method for manufacturing a precision ball screw with high hardness, high wear resistance, low roughness, low noise and long fatigue life.

本发明采用38CrMoAl为材料，包括下料、校直、车外圆、调质、修研中心孔、磨外圆、螺纹磨磨削丝杠螺纹、铣键槽或方身、钳工工艺、去应力、研中心孔、辉光离子氮化、脉冲电化学复合光整加工、倒两端不完整牙1/4圈、螺纹磨削倒角螺纹及顶端45°处理步骤。The present invention uses 38CrMoAl as the material, including blanking, straightening, turning the outer circle, quenching and tempering, repairing the center hole, grinding the outer circle, thread grinding and grinding screw thread, milling keyway or square body, fitter process, stress relief, Research center hole, glow ion nitriding, pulse electrochemical composite finishing, reverse 1/4 turn of incomplete teeth at both ends, thread grinding and chamfering thread and top 45° processing steps.

本发明以现有的下料、校直、车外圆、热处理、修研中心孔、磨外圆、铣键槽或方身、螺纹粗磨、倒两端不完整牙1/4圈、螺纹磨削倒角螺纹及顶端45°处理工艺步骤为基础，选用38CrMoAl为丝杠材料，在粗磨螺纹达到精度要求后对丝杠整体进行辉光离子氮化处理，辉光离子氮化后的丝杠不再进行去应力、半精磨、精磨工艺，而是应用脉冲电化学复合光整技术进行光整加工。The present invention uses the existing blanking, straightening, turning the outer circle, heat treatment, repairing the center hole, grinding the outer circle, milling the keyway or square body, rough thread grinding, inverted 1/4 turn of incomplete teeth at both ends, and thread grinding. Based on the chamfered thread and 45° treatment process steps at the top, 38CrMoAl is selected as the lead screw material. After the rough grinding thread meets the precision requirements, the overall lead screw is treated with glow ion nitriding, and the lead screw after glow ion nitriding Instead of stress relief, semi-fine grinding, and fine grinding processes, pulse electrochemical composite finishing technology is used for finishing processing.

本发明的优点体现在：The advantages of the present invention are reflected in:

1、使用38CrMoAl，有利于辉光离子氮化的进行；1. The use of 38CrMoAl is conducive to the progress of glow ion nitriding;

2、丝杠调质、粗磨后进行辉光离子氮化，可使丝杠硬度达到HRC70，远超过一般丝杠的硬度，从而使丝杠的耐磨性大大增加，并且控制好辉光离子氮化的工艺参数，可使丝杠不改变精度，也不需要再进行去应力处理；2. After quenching and tempering of the lead screw and rough grinding, glow ion nitriding can make the hardness of the lead screw reach HRC70, far exceeding the hardness of the general lead screw, so that the wear resistance of the lead screw is greatly increased, and the glow ion is well controlled The process parameters of nitriding can make the screw not change the accuracy, and no stress relief treatment is needed;

3、采用脉冲电化学复合光整技术对丝杠进行光整加工，可使丝杠表面粗糙度粗磨后一步降低至Ra0.1μm以下，最低可达到Ra0.02μm，从而加工出超光滑的表面；3. The lead screw is finished by pulse electrochemical composite finishing technology, which can reduce the surface roughness of the lead screw to below Ra0.1μm in one step after rough grinding, and the minimum can reach Ra0.02μm, so as to process an ultra-smooth surface ;

4、由于丝杠硬度高、表面粗糙度低，可使丝杠的疲劳寿命较普通丝杠增加3-5倍，使用噪声降低6-8分贝；4. Due to the high hardness and low surface roughness of the lead screw, the fatigue life of the lead screw can be increased by 3-5 times compared with ordinary lead screws, and the operating noise can be reduced by 6-8 decibels;

5、丝杠粗磨、渗氮(硬度达HRC70)后直接进行光整，不需进行精磨、研磨和抛光，大幅度节省了机械加工的时间，使生产效率大大提高；5. After rough grinding and nitriding (hardness up to HRC70) of the lead screw, it can be finished directly without fine grinding, grinding and polishing, which greatly saves the time of machining and greatly improves the production efficiency;

6、脉冲电化学复合光整加工的效率与丝杠表面硬度无关，对于HRC70硬度的表面也能很快完成光整加工；6. The efficiency of pulse electrochemical composite finishing has nothing to do with the surface hardness of the lead screw, and the finishing can be completed quickly for the surface with HRC70 hardness;

7、光整加工过程中不产生磨削力和磨削热，不产生附加应力，丝杠的精度高，表面也不产生磨削烧伤和裂纹；7. No grinding force, no grinding heat, no additional stress will be generated during the finishing process, the precision of the lead screw is high, and there will be no grinding burns and cracks on the surface;

8、光整后的丝杠调整装配后可直接提供给用户，不需要进行长时间跑和，生产周期大大缩短；8. The finished lead screw can be directly provided to the user after adjustment and assembly, without the need for long-term running and processing, and the production cycle is greatly shortened;

9、由于减少了半精磨、精磨的工序，车间里由于磨削加工所生产的油雾大幅减少，对环境的污染也大幅减少，是一种绿色制造方法。9. Due to the reduction of semi-fine grinding and fine grinding processes, the oil mist produced by grinding in the workshop is greatly reduced, and the pollution to the environment is also greatly reduced. It is a green manufacturing method.

另，所述脉冲电化学复合光整加工时脉冲频率为4-7KHz；脉冲电流峰值为150-300A；工作比为20-40％；工具压力为8-15N。In addition, the pulse frequency is 4-7KHz during the pulse electrochemical composite finishing process; the peak value of the pulse current is 150-300A; the working ratio is 20-40%; the tool pressure is 8-15N.

所述辉光离子氮化处理时，将清洗过的丝杠装炉，在阴极底盘上沿圆周按内、中、外三层均匀摆放丝杠，然后经抽真空、打弧、升温、保温，待温度降到200℃时，充气开炉，取出加工的工件。During the glow ion nitriding treatment, put the cleaned lead screw into the furnace, place the lead screw evenly in three layers along the circumference of the cathode chassis, and then vacuumize, arc, heat up and keep warm. , when the temperature drops to 200°C, inflate and start the furnace, and take out the processed workpiece.

所述抽真空时，在25min内使炉内压力低于50Pa。When said vacuuming, make the pressure in the furnace lower than 50Pa within 25min.

所述打弧时，将电源脉宽调为15-20μs，电源的接通率约为18％，电压由点燃电压渐增至800-850V，炉内压力为40-120Pa，打弧时间在1.5h以内，打弧结束后，控制温度达100±2℃。When arcing, adjust the pulse width of the power supply to 15-20μs, the turn-on rate of the power supply is about 18%, the voltage gradually increases from the ignition voltage to 800-850V, the pressure in the furnace is 40-120Pa, and the arcing time is 1.5 Within h, after the arc is over, control the temperature to 100±2°C.

所述升温是：打弧结束后，脉冲电源的脉宽渐调至90μs，电源的接通率约为75％，逐渐增大电压和电流加热，加热速度小于3℃/min，280℃开始通NH₃，控制NH₃的流量为0.35L/min。The temperature rise is: after the arc is over, the pulse width of the pulse power supply is gradually adjusted to 90μs, the power supply connection rate is about 75%, and the voltage and current are gradually increased to heat, the heating speed is less than 3°C/min, and the power supply starts at 280°C. NH ₃ , control the flow rate of NH ₃ to 0.35L/min.

所述保温是：当温度升到500-520℃后，以0.7-1.2L/min的流量通入NH₃，保温3h，保温气压约600Pa。The heat preservation is: when the temperature rises to 500-520°C, NH ₃ is introduced at a flow rate of 0.7-1.2 L/min, and the heat preservation is 3 hours, and the heat preservation pressure is about 600Pa.

附图说明 Description of drawings

图1为本发明采用的脉冲电化学复合光整技术中所使用脉冲电流波形图。Fig. 1 is a pulse current waveform diagram used in the pulse electrochemical composite finishing technology adopted in the present invention.

具体实施方式 Detailed ways

以下结合实例对本发明做进一步说明：The present invention will be further described below in conjunction with example:

选用38CrMoAl为丝杠材料，基于脉冲电化学复合光整技术的精密滚珠丝杠的制造工艺步骤为：38CrMoAl is selected as the material of the screw, and the manufacturing process steps of the precision ball screw based on the pulse electrochemical composite finishing technology are as follows:

下料、校直、车外圆、调质、修研中心孔、磨外圆、螺纹磨磨削丝杠螺纹、铣键槽或方身、钳工工艺、去应力、研中心孔、辉光离子氮化、脉冲电化学复合光整加工、倒两端不完整牙1/4圈、螺纹磨削倒角螺纹，最后进行顶端45°处理。Blanking, straightening, turning outer circle, quenching and tempering, repairing center hole, grinding outer circle, thread grinding and grinding screw thread, milling keyway or square body, fitter process, stress relief, center hole grinding, glow ion nitrogen Chemical, pulse electrochemical composite finishing, chamfering 1/4 turn of incomplete teeth at both ends, thread grinding and chamfering threads, and finally 45° treatment on the top.

其中，脉冲电化学复合光整技术在本发明工艺中的应用是本发明所独有的，具体工艺参数如下：Wherein, the application of the pulse electrochemical composite finishing technology in the process of the present invention is unique to the present invention, and the specific process parameters are as follows:

1、所使用脉冲电流波形如图1：1. The pulse current waveform used is shown in Figure 1:

2、脉冲频率为4-7KHz；2. The pulse frequency is 4-7KHz;

3、脉冲电流峰值为150-300A；3. The peak value of pulse current is 150-300A;

4、工作比为20-40％；4. The working ratio is 20-40%;

5、工具压力为8-15N。5. Tool pressure is 8-15N.

另，辉光离子氮化处理的具体工艺过程：In addition, the specific process of glow ion nitriding treatment:

将清洗过的丝杠装炉，在阴极底盘上沿圆周按内、中、外三层均匀摆放50根左右丝杠，随炉装试样4块。具体工艺过程及参数如下：Put the cleaned lead screws into the furnace, place about 50 lead screws evenly in three layers of inner, middle and outer layers on the cathode chassis along the circumference, and load 4 samples with the furnace. The specific process and parameters are as follows:

1、抽真空：25min内使炉内压力低于50Pa。1. Vacuuming: Make the pressure in the furnace lower than 50Pa within 25 minutes.

2、打弧：将电源脉宽调为15-20μs，电源的接通率约为18％，电压由点燃电压渐增至800-850V，炉内压力为40-120Pa，打弧时间在1.5h以内，打弧结束后，温度达100℃左右。2. Arcing: Adjust the pulse width of the power supply to 15-20μs, the connection rate of the power supply is about 18%, the voltage gradually increases from the ignition voltage to 800-850V, the pressure in the furnace is 40-120Pa, and the arcing time is 1.5h Within, after the arc is over, the temperature reaches about 100°C.

3、升温：打弧结束后，脉冲电源的脉宽渐调至90μs，电源的接通率约为75％，逐渐增大电压和电流加热，加热速度小于3℃/min，280℃开始通NH₃，控制NH₃的流量为0.35L/min。3. Heating: after arcing, the pulse width of the pulse power supply is gradually adjusted to 90μs, the power supply connection rate is about 75%, gradually increase the voltage and current heating, the heating speed is less than 3°C/min, and the NH starts at 280°C _3. Control the flow rate of NH ₃ to 0.35L/min.

4、保温：当温度升到500-520℃后，以0.7-1.2L/min的流量通入NH₃，保温3h，保温气压约600Pa，4. Heat preservation: when the temperature rises to 500-520°C, feed NH ₃ at a flow rate of 0.7-1.2L/min, hold heat for 3 hours, and hold heat pressure at about 600Pa.

5、停机，冷却3h，待温度降到200℃时，充气开炉，取出加工的工件。5. Shut down and cool for 3 hours. When the temperature drops to 200°C, start the furnace with gas and take out the processed workpiece.