XK5040数控立式铣床及控制系统设计外文翻译Word格式文档下载.docx

1、与不同铣床相较数控铣床用三个数控伺服系统替代了传统的机械进给系统，其外形和结构与普通铣床类似。数控铣床的设计主如果进行主运动系统与进给系统的机械结构设计和控制系统设计。下面别离作简单介绍。一、整体方案设计 本文主如果针对经济型数控立式铣床进行设计，为了锻炼自己的机床设计的能力，这里主运动系统采用常规机床设计的方式，即采用齿轮变速系统来实现主轴的变速。进给系统采用步进电机开环控制，通过齿轮传动带动滚珠丝杠传动，通过滚珠丝杠螺母副时刻进给运动。控制系统采用MCS-51系列单片机为中央处置器的计算控制系统。二、主运动系统设计由于这里采用齿轮变速系统来实现主轴的变速，选定公比，肯定各级传送机床常常利用

2、的公比 为或，考虑适当减少相对速度损失，这里取公比为 =，按照给出的条件：主运动部份Z=18级，按照标准数列表，肯定各级转速为：（30，60，75，95，118，150，190，235，300，375，475，600，750，950，1180，1500R/min）。按照“前多后少”、“前密后疏”的原则肯定其结构式为18=x，一、传动比的分派由于齿轮传动比的限制，机床主传动系统中，齿轮副的极限传动比：a, 升速传动中，最大传动比 2 ，过大，容易引发振动的噪音。b, 降速传动中，最小传动比 1/4。过小，则主动齿轮与被动齿轮的直径相差太大将致使结构庞大。分派最小传动比a,决定轴V-VI和VI-的

3、传动比，按照台式铣床的结构特点，及对同类车床的比较，为使传动平稳取其传动比为1，b,决定各变速组的传动比；由前面2轴的转速及中间轴转速的分析，及齿轮传动比的此刻，按照“前缓后急”的原则，取轴IV-V的最小降速比为极限值的1/4， =， =4，轴III-IV和轴II-III均取=1/二、主运动系统的机械结构设计这里采用齿轮变速系统,这是大、种型数控机床采用较多的一种方式。通过少数几对齿轮减速，扩大了输出扭矩，以知足主轴对输出扭矩特性的要求。一部份小型数控机床业采用此种传动方式，以取得强力切屑时所需要的扭矩。滑移齿轮的移位拨叉实现。着与普通机床的设计一样。数控机床主轴部件的精度、刚度和热变形对加工

4、质量有直接影响。由于加工进程中不对数控机床进行人工调整，因此这些影响就更为严峻。机床主轴采用双列和单列圆锥滚子轴承 ，这种轴承径向和轴向刚度高，能经受重载荷，尤其能经受较强的动载荷，安装与调整性能也好。可是，这种轴承限制了主轴的最高转速和精度，因此利用中等精度、低速与重载的数控机床。在主轴的机构上，要处置好卡盘和刀架的装夹、主轴的卸荷、主轴轴承的定位和间隙调整、 主轴部件的润滑和密封和工艺上的其他一系列问题。为了尽可能减少主轴部件温升热变形对机床工作精度的影响，通常利用润滑油的循环系统把主轴部件的热量带走，使主轴部件与箱体维持恒定的温度。在某些数控镗、铣床上采用专用的制冷装置，比较理想的实现了

5、温度控制。最近几年来，某些数控机床的主轴轴承采用高级油脂，用封入方式进行润滑，每加一次油脂能够利用7年至10年。为了使润滑油和油脂不致混合，通常采用迷宫密封方式。三、 进给系统设计 通常，一个典型的数控机床进给系统，由位置比较，放大元件、驱动单元、机械传动装置和检测反馈元件等几部份组成。其中，机械传动装置是位置控制中的一个重要环节。这里所说的机械传动装置，是指将驱动源的旋转运动变成工作台的直线运动的整个机械传动链，包括齿轮装置、丝杠螺母副等中间传动机构。齿轮传动是应用超级普遍的一种机械传动，各类机床的传动装置中几乎都有齿轮传动。在数控机床伺服进给系统中采用齿轮传动装置的目的有两个。一是将高转速

6、的转矩的伺服电机（如步进电机、直流和交流伺服电机等）的输出改变成低转速大转矩的执行件的输入；另一是使滚珠丝杠和工作台的转动惯量在系统中专有较小的比重。另外，对于开环系统还能够保证所要求的运动精度。 为了尽可能减小齿侧间隙对数控机床加工精度的影响，常常在结构上采取办法，以减小或消除齿轮副的空程误差。如采用双片齿轮错齿法、利用偏心套调整齿轮副中心距或采用轴向垫片调整法消除齿轮侧隙。这里进给系统采用步进电机开环控制，由滚珠丝杠螺母副来实现 ，纵向和横向进给采用130BF001型步进电机驱动，经圆柱齿轮传动带动滚珠丝杠传动，通过丝杠螺母机构来实现；垂直方向进给运动由150BF003型步进电机驱动，经圆

7、锥齿轮带动滚珠丝杠传动。纵向和横向齿轮可采用斜齿轮弹簧调整法来消除齿轮间隙；垂直方向的齿轮间隙可采用圆锥齿轮周向弹簧调整法来消除。为了提高进给系统的灵敏度、定位精度和避免爬行，必需降低数控机床进给系统的摩擦并减少静、动摩擦系数之差。因此，形成不太长的直线运动机构常常利用滚珠丝杠副。滚珠丝杠副的传动效率高达85%-98%，是普通滑动丝杠副的2-4倍。滚珠丝杠副的摩擦角小于1，因此不自锁。若是滚珠丝杠副驱动起落运动（如主轴箱或起落台的起落），则必需有制动装置。滚珠丝杠的静、动摩擦系数实际上几乎没有什么不同。它能够消除反向间隙并施加预载，有助于提高定位精度和刚度。滚珠丝杠由专门工厂制造。咱们按照载荷

8、选用即可。四、控制系统硬件设计按照经济性和机械结构的控制要求，XK5040立式铣床控制系统选用MCS-51系列单片机组成，纵向、横向及垂直方向均采用步进电机控制，三个坐标均采用硬件环形分派器，控制系统的功能包括X向、Y向、Z给伺服运动；键盘显示；面板管理；行程控制和其他功能、例如光隔离电路、功率放大电路、红绿灯显示等。这里咱们选用8031芯片作为CPU。由于8031芯片内部无程序存储器，需要扩展外部程序存储器支持，同时8031内部只有128B的数据存储器供用户利用，也不能知足控制系统的要求，故需要扩展程序存储器2764和数据存储器6264各两片。8031单片机共有四个位并行I/O，但可供用户利

9、用的只有口和部份口，不能知足输入输出口的需要，因此系统必需扩展输入输出接口电路。这里按照系统功能及需要,扩展一片8155和一片8255可编程接I/O口芯片。另外还需设计一些辅助电路如越界报警和急停处置电路、复位电路、光电隔离电路、脉冲分派器（环形分派器）等。整个设计进程中，都是按照数控立式铣床的实际情形，以高效、经济为目的，使咱们设计的铣床应用于实际，具有实际利用价值。The open system merit of Computer Numerical ControlThe open system merit is the system simple, the cost low, but t

10、he shortcoming is the precision is low. The reverse gap, the guide screw pitch error, stop inferiorly can affect the pointing accuracy by mistake. Following several kind of improvements measure may cause the pointing accuracy distinct improvement.1. reverse gap error compensates The numerical contro

11、l engine bed processing cutting tool and the work piece relative motion is depends upon the drive impetus gear,the guide screw rotation, thus the impetus work floor and so on moves the part to produce moves realizes. As traditional part gear, guide screw although the manufacture precision is very hi

12、gh, but always unavoidably has the gap. As a result of this kind of gap existence, when movement direction change, starts the section time to be able to cause inevitably actuates the part wasting time, appears the instruction pulse to push the motionless functional element the aspect. This has affec

13、ted the engine bed processing precision, namely the instruction pulse and actual enters for the step does not tally,has the processing error therefore, the split-ring numerical control system all establishes generally has the reverse gap error compensatory function, with by makes up which wastes tim

14、e the step reverse gap difference compensates is first actual reverse enters for the error, converts the pulse equivalent number it, compensates the subroutine as the gap the output, when the computer judgment appears when instruction for counter motion, transfers the gap to compensate the subroutin

15、e immediately, compensates the pulse after the output to eliminate the reverse gap to carry on again normally inserts makes up the movement.2. often the value systematic characteristic position error compensatesA kind of storehouse by transfers for the designer. Like this in the components design st

16、age, the designer only must input the characteristic the parameter, the system direct production characteristic example model: We must save the related characteristic class in the database the structure information, the database table collection are use in saving this part of related information. Ac

17、cording to the characteristic type definition need, we defined the characteristic class code table, the characteristic class edition information have outstanding shown the characteristic type; Defined the characteristic class structure outstanding to reach the characteristic class the structure; And

18、 relates through the components characteristic disposition table and the components characteristic level information. The characteristic level data sheet collection is this components model database design core, has recorded characteristic example information and so on model design, craft. The chara

19、cteristic structure table has recorded the characteristic geometry structure; The characteristic size table, the characteristic shape position table of limits, the characteristic surface roughness table has recorded the characteristic project semantics quotation; The size table, the shape position t

20、able of limits, the surface roughness table saved all components characteristic data message. In the characteristic level, using characteristic ID, geometry principal linkage and so on essential factor ID, size ID, common difference ID, roughness ID carries on the data retrieval. We apply this compo

21、nents information model database under the factory environment some module CAD in the AM integrative system, has realized CAD and the CAPP characteristic information sharing well. Main use ready-made CAD/the CAM software （Unigra phics 1I） carries on the product design and the NC programming in this

22、system, and through carries on two times of developments gains components to this software the size information; At the same time uses the dialogue window which develops voluntarily, lets design the personnel to input other characteristic information alternately, realizes this software and the syste

23、m sharing database connection. When assistance technological design, the technological design personnel through the procedure inquiry function, inquires the components information from the sharing database which needs, carries on the interactive technological design. Thus has facilitated the CAPP co

24、mponents information acquisition, enhanced the technological design efficiency. When carries on the NC programming using UG, may from the sharing database gain the craft and the manufacture information which needs, carries on various working procedures the knife axle design and the processing simula

25、tion establishes an absolute zero spot on the numerical control engine bed, the actual various coordinate axes syzygy completely position error, makes the curve in order to determined compensates the spot. Attempts l to show is an actual position error curve, （error） carries on this curve y-coordina

26、te take the pulse equivalent as the unit the division, makes the horizontal line, each horizontal line and the curve point of intersection namely compensates the spot for the goal. Chart 1 the center 1 to 6 oclock place position errors for, needs to do reduces the pulse to compensate; But needs to c

27、arry on 6 to 9 adds the pulse to compensate in the chart the shadow partially for to compensate the area. Compensates the range of points these to become the errorThe calibration corrections stores the computer, when work table by zero displacement in position, installs sends out the absolute zero p

28、oint localization signal in the absolute zero point micros witch, later computer as necessary will send out the goal to compensate to compensate the signal, will carry on the position error to the engine bed to compensate. The cosine generator assigns slide guage initiation signal a electricity and

29、by step of transmission.3. feedbacks compensates the open-loop controlChart 2 has produced this kind of system schematic diagram. This system surveys two parts by the open-loop control and the induction synchromesh direct position to be composed. Here position examination does not serve as the posit

30、ion the feedback, but is compensates the feedback as the position error. Its cardinal principle is: Installs the instruction pulse by the engine bed numerical control which CNC sends out, on the one hand the supplies open system, the control step-by-steps the electrical machinery according to the in

31、struction revolution, and the direct drive platen moves, constitutes the open-loop control; On the other hand this instruction pulse supplies the induction synchromesh the measurement system （namely digitally, cosine generator）, as position demand signal a by. The work in the warning way induction synchromesh this time not only is the position sensor, also is the comparator, it by, The cosine generator assigns slide guage initiation signal a electricity and by step of transmission.4.