数控机床润滑系统控制的改进

数控机床润滑系统控制的改进机床润滑系统的设计、调试和维修保养，对于提高机床加工精度、延长机床使用寿命等都有着十分重要的作用。

但是在润滑系统的电气控制方面，仍存在以下问题：一是润滑系统工作状态的监控。

数控机床控制系统中一般仅设油箱油面监控，以防供油不足，而对润滑系统易出现的漏油、油路堵塞等现象，不能及时做出反应。

二是设置的润滑循环和给油时间单一，容易造成浪费。

数控机床在不同的工作状态下，需要的润滑剂量是不一样的，如在机床暂停阶段就比加工阶段所需要的润滑油量要少。

针对上述情况，在数控机床电气控制系统中，对润滑控制部分进行了改进设计，时刻监控润滑系统的工作状况，以保证机床机械部件得到良好润滑，并且还可以根据机床的工作状态，自动调整供油、循环时间，以节约润滑油。

1 润滑系统工作状态的监控润滑系统中除了因油料消耗，油箱油过少而使润滑系统供油不足外，常见的故障还有油泵失效、供油管路堵塞、分流器工作不正常、漏油严重等。

因此，在润滑系统中设置了下述检测装置，用于对润滑泵的工作状态实施监控，避免机床在缺油状态下工作，影响机床性能和使用寿命。

1) 过载检测在润滑泵的供电回路中使用过载保护元件，并将其热过载触点作为PMC系统的输入信号，一旦润滑泵出现过载，PMC系统即可检测到并加以处理，使机床立即停止运行。

2) 油面检测润滑油为消耗品，因此机床工作一段时间后，润滑泵油箱内润滑油会逐渐减少。

如果操作人员没有及时添加，当油箱内润滑油到达最低油位，油面检测开关随即动作，并将此信号传送给PMC系统进行处理。

3) 压力检测机床采用递进式集中润滑系统，只要系统工作正常，每个润滑点都能保证得到预定的润滑剂。

一旦润滑泵本身工作不正常、失效，或者是供油回路中有一处出现供油管路堵塞、漏油等情况，系统中的压力就会显现异常。

根据这个特点，设计时在润滑泵出口处安装压力检测开关，并将此开关信号输入PMC系统，在每次润滑泵工作后，检查系统内的压力，一旦发现异常则立即停止机床工作，并产生报警信号。

2 润滑时间及润滑次数的控制为了要使机床运动副的磨损减小，必须在运动副表面保持适当的清洁的润滑油膜，即维持摩擦表面之间恒量供油以形成油膜。

但是数控机床运动副需要的润滑油量不是太多时，采用连续供油方式既不经济也不合理。

因为过量供油与供油不足同样是有害的、会产生附加热量、污染和浪费。

因此，润滑系统均采用定期、定量的周期工作方式。

集中润滑系统本身可以配置微处理器，专门用于设定润滑泵停止的时间和每次供油时间，以控制润滑泵间隙工作，设计人员往往也借此来简化自己的PMC程序。

但机床在不同的工作状态下，如刚刚通电初始工作阶段、加工运行和因调整、检测工件而使机床暂停运行时，机床对润滑油的需求量各不相同。

在配置FANUC数控系统的机床中，通常通过控制润滑泵工作的时间来调节提供的润滑油量，但是，习惯考虑的是润滑系统在机床加工运行状态下的供油方式，而没有顾及其它工作状态，这样，当机床处于其它工作状态时，润滑系统所提供的润滑油量要么不够，要么过多。

机床导轨需要的润滑油量近似可用下面公式计算：(长度+移动行程)×宽度×K。

从公式中可以看出，机床导轨需要的润滑油量与该导轨上的轴的移动距离有关。

欧美生产的数控系统大多以行程量作为依据，来控制润滑泵工作，间隙供油，并在系统中提供了相应的参数，便于机床制造商通过PMC程序对润滑泵进行电气控制。

而在FANUC 0i系统中没有类似的控制方法，为了能在配置FANUC 0i的数控机床上，采用近似的供油方式控制润滑泵工作，我们改进了润滑控制部分的电气设计，让控制系统能根据机床的具体工作情况自动调整润滑泵工作频率和每次的工作时间，在机床暂停时适当减少供油量，而机床初始工作时适当增加。

现将润滑泵的工作状态分成三类，分别设置润滑泵工作时间和频率。

1) 开机初始阶段机床开机，润滑泵即刻开始工作，连续供油一段时间，此时润滑泵工作的时间T1比正常状态下的要长，以便在短时间内提供足够润滑油，使机床导轨上迅速形成一层油膜。

润滑泵运行时间由PMC程序中的TMRB指令设定。

与TMR指令不同，由TMRB设定的时间，用户不能随意修改调整。

2) 加工运行阶段机床开机以后，经过空载运行预热后，进入稳定工作状态。

此后，控制系统控制润滑泵间歇工作，以保证机床导轨能够得到定期、定量的润滑。

润滑泵每次工作的时间和其停止的时间由PMC程序中的TMR指令设定。

TMR设定的时间参数，用户可以在PMC数据窗口中根据需要适当调整。

3) 暂停阶段工件待加工或加工完毕时，机床往往处于暂停工作状态，润滑油的需求量相应减少，因此，需要及时调整控制方式，适当延长润滑泵停止工作的时间，以减少其工作频率，从而减少油品消耗。

实现的关键是机床处于暂停状态时，系统如何获知。

FANUC 0i数控系统中提供了信号MVX(F102.0)、MVY(F102.1)、MVZ(F102.3)，用于反映机床各轴的移动状态。

如果该信号状态为“0”，表明相应机床轴静止不动，如果所有移动轴均静止不动，则表明机床此时处于暂停工作状态。

所以，只要上述所有信号状态都为“0”，通过设计，PMC程序自动改变润滑泵工作及停止时间。

此时，润滑泵工作的时间T2和停止的时间T3均使用TMRB 指令设定，同样，用户不可以随意修改这两个时间参数。

3 润滑报警信号的处理1) 压力异常数控机床中润滑系统为间歇供油工作方式。

因此，润滑系统中的压力采用定期检查方式，即在润滑泵每次工作以后检查。

如果出现故障，如漏油、油泵失效、油路堵塞，润滑系统内的压力就会突然下降或升高，此时应立即强制机床停止运行，进行检查，以免事态扩大。

2) 油面过低以往习惯的处理方法是将“油面过低”信号与“压力异常”报警信号归为一类，作为紧急停止信号。

一旦PMC系统接收到上述信号，机床立即进入紧急停止状态，同时让伺服系统断电。

但是，与润滑系统因油路堵塞或漏油现象而造成“压力异常”的情况不同，如果润滑泵油箱内油不够，短时间不至于影响机床的性能，无需立即使机床停止工作。

但是，出现此现象后，控制系统应及时显示相应的信息，提醒操作人员及时添加润滑油。

如果操作人员没有在规定时间内予以补充，系统就会控制机床立即进入暂停状态。

只有及时补给润滑油后，才允许操作人员运行机床，继续中断的工作。

针对“油面过低”信号，这样的处理方法可以避免发生不必要的停机，减少辅助加工时间，特别是在加工大型模具的时候。

在设计时，我们将“油面过低”信号归为电气控制系统“进给暂停”类信号，采用“提醒——警告——暂停，禁止自动运行”的报警处理方式。

一旦油箱内油过少，不仅在操作面板上有红色指示灯提示，在屏幕上也同时显示警告信息，提醒操作人员。

如果该信号在规定的时间内没有消失，则让机床迅速进入进给暂停状态，此时暂停机床进行任何自动操作。

操作人员往油箱内添加足够的润滑油后，只需要按“循环启动”按钮，就可以解除此状态，让机床继续暂停前的加工操作。

4 结语数控机床电气控制设计过程中，润滑系统的处理若被忽视，对于机床的使用者而言，机床各部件能否定期定量得到润滑，却是十分重要的问题。

应不断改进、完善产品的设计，减少机床出现故障的次数，提高产品的可靠性。

The number controls the improvement that machine bed lubricate the system the controlThe machine bed lubricates the design of the system and adjust to try with maintain to maintain, having got increases machine bed process accuracy, extension machine bed service life etc. very much the very important function.But in the aspects of electricity control that lubricate the system, still exsits below problem:An is to lubricate the system work appearance supervise and control.Number control the machine bed control system inside to establish generally and only the fuel tank oil supervise and control, the in order to prevent provides the oil the shortage, but to lubricate the system appear easily of leak the oil, oil road stop to wait the phenomenon, can't on time do the reaction.Two is a lubrication to establishes circulation with give oil time one, result in easily wasted.The number under the different work appearance control the machine bed, the amount of lubricant of the demand is different, such as in stage in pause in bed in machine compare an amount of lubricant for needing that process the stage want to be little.Aim at the above circumstance, in count control machine bed electricity control system, to lubricate to control the part proceeded the improvement designs, supervising and control the work condition of the lubrication system every moment, toing guarantee the machine bed machine parts get the good lubrication, and can also according to the work appearance of the machine bed, automatic adjust to provide the oil, circulation time, to economize the lubricant.1 Lubricate the system the work the appearance supervise and controlLubricate the system inside in addition to making the lubrication system provide the oil shortage because of the oil anticipates the depletion, fuel tank oil over little, familiar breakdown still contain oil pump expiration, provide the pipeline road stop, divide to flow the machine work falsely often, leak the oil to wait seriously.Therefore, establishes to descend to say the examination device in lubricate system, used for the work to pump to lubrication appearance puts supervise and control into practice to, avoiding the machine bed the work while lacking the oil appearance, affect the machine bed function with the service life.1) Over carry to examine to used to carry to protect a dollar an importation for, combining its heat over carrying the order to be used as the system of PMC signal in power supply back track that lubrication pump, once lubricate the pump appeared to carry, the system of PMC can immediately examine and put paid to, make machine bed stopped the movement immediately.2) The oil examines lubricant as the expendable goods, for this reason machine bed work after a period of time, lubricating pump lubricant inside the fuel tank will reduce gradually.If operate the personnel have no on time increase, be the lubricant inside the fuel tank arrive lowest oil, oil examination the switch acts immediately, combining to deliver this signal to PMC system the proceeding handles.3) Pressure examination machine bed the adoption passes into the type concentrates lubrication system, only system work normal, each lubrication orders it can guarantee to get the pre-arranged lubricant.Once lubricate to pump oneself the work falsely often, lose efficacy, or is to provide to have in the oil back track a the place appears to provide the pipeline road stop, leak oil etc. circumstance, pressure in the system will present the abnormality.According to this characteristics, design at lubricate the pump to install the pressure examination switch exit, combine to input this switch signal into the PMC system, after every time lubricate pump work, check pressure in the system, once discover the abnormality then stop immediately the machine bed works, combining the creation report to the police the signal.2 Lubricate the control between time and lubrication number of timesThe in order to makes the machine bed exercise the vice- wear and tear lets up, must at exercise vice- surface keep appropriate and detergent lubricant , then maintain the friction surface an amount of provides the oil to become oil .But the number control the lubricant that machine bed exercise vice- demand the deal is not too many, adoption continue provide the oil method since uneconomical too not reasonable.Because too many to provide the oil with provide the oil the shortage similarly harmful, will produce the additional calories, pollution with wasted.Therefore, lubricate the system to all adopt the periodical and quantitative period the work the method.Concentrate lubrication system oneself can install the microprocessor, used for exclusively the enactment lubricates to pump time of the ceasing with every provide oil time, lubricate pump cleft to work with the control, design the personnel to usually also borrow this to simplify own the procedure of PMC.But the machine bed is under the different work appearance, such as just switch on electricity the beginning start the stage in work and process the movement similar to made machine bed pause circulated because of adjust, examination work piece, machine bed to lubricate the oily demand eachly not.In install FANUC number control the machine bed of the system, usually pass the control lubricates time that pump the workto provide to the amount of lubricant that regulate, but, what habit consider is to lubricates the system to process in the machine bed the movement appearance descend of provide the oil method, but did not have regard for the other the work the appearance, like this, crash the bed be placed in other work appearance, lubricate the system an amount of lubricant for providing want the 么not enough, wanting the 么excessive.The machine bed leads the amount of lubricant of the demand look like and can use underneath formula calculation:( length+ move the route of travel) × width × K.Can see from the formula inside, the machine bed leads the lubricant of the demand measures to have something to do with should leading the axial ambulation distance of the 轨.The number that Europe and America produce controls the system to measures with the route of travel mostly conduct and actions according to, control lubrication pump work, the cleft provides the oil, and provided the homologous parameter in system, the easy to machine bed manufactory pass the procedure of PMC to the lubrication pump proceed electricity control.But has no similar control method in FANUC a system, for the sake of can in installing a the 0 is of FANUCly the number controls machine bed, the adoption looks like of provide the oil method the control to lubricate to pump the work, we improved the lubrication the control part of electricity designs, letting control system can according to machine bed of concrete work the circumstance adjusts automatically lubrication pump work frequency with every work time, at machine bed pause hour appropriate the decrease provides the amount of oil, but appropriate increment for machine bed beginning to start work.Will lubricate now the work appearance of the pump be divided into three type, establishes respectively lubrication pump work time with frequency.1) The machine beginning that open the machine bed starts the stage opens the machine, lubricating the pump to begin to work right away, continuing to provide oil a period of time, lubricating at this time the time T1 that pump the work compares the normal appearance descends of want long, in order to provide the enough lubricant in the in a short time, make the machine bed lead the. the top become quickly a layer oil .Lubricate pump circulate time be set up by PMC TMRB in the procedure instruction.Different from the instruction of TMR, from time that TMRB set up, the customer can't modify the adjustment as one's pleases.2) Processing the stage in movement machine bed opens the machine hereafter, passing by to get empty to transport the line prepare the hot empress, entering the stable work appearance.Henceforth, control system control lubricate the pump intermittent work, to guarantee the machine bed lead the can get periodical, quantitative lubrication.Lubricate time of the every work in pump to be set up by PMC TMR in the procedure instruction with time of its ceasing.Time parameter that TMR set up, customer can in PMC data window way according to need the appropriate adjustment.3) Stage in pause a time for treating processing or processing completing, machine bedusually being placed in pause working appearance, lubricating oily demand cowgirl reducing, therefore, needing on time adjusting controling way, appropriate extension lubricating pumping stopping work, to reduce its work frequency, from but reduce the oil article the depletion.When key of realizing is a machine bed to be placed in the pause appearance, the system how to have learned that.The number of FANUC controled to provide the signal MVX( F102.0), MVY( F102.1), MVZ( F102.3) in the system, useding for reflecting machine bed each axial ambulation appearance.If the signal's appearance is a "0", express cowgirl machine bed stalk static motionless, if all ambulation stalk all static motionless, then express the machine bed to be placed in at this time pause work appearance.So, above only all signal appearance all for"0", pass the design, the procedure of PMC changes automatically lubrication pump work and stop time.This time, lubricate the time T2 that pump the work to use with the time T3 of the ceasing all the instruction of TMRB set up, same, customer must not modify these two time parameter as one's pleases.3 Lubricate to report to the police the signal handles1) Pressure excrescent the number controls to lubricate system as in the machine bed intermittent provide oil work method.Therefore, lubricate pressure in the system adoption periodical check method, at lubricate the pump the every work later on check.If appear the breakdown, if leaks oil, oil pump expiration, the oil road stops, lubricate the pressure in the system and then will descend or go up suddenly, this time should immediately compulsory the machine bed stops the movement, proceeding the check, in order to prevent the circumstances extends.2) Oil over low handles habitually before the method is to report to the police with" pressure abnormality" the " oil over low" signal to signal to classify a type, be used as the urgent ceasing signal.Once the system of PMC receives the above signal, the machine bed enters the urgent ceasing appearance immediately, let servo system cut the power at the same time.But, with lubricate the system make the circumstance of the " pressure abnormality" different because the oil road stops or leaks the oil phenomenon, if lubricate to pump the oil inside the fuel tank not enough, short time affects the function of the machine bed not to the extent of, having no to need to make the machine bed stop the work immediately.But, after appearing this phenomenon, control system should on time show the homologous information, remind to operate the personnel on time increase the lubricant.If operate the personnel did not give complement in rule time, system will control the machine bed to enter the pause appearance immediately.Only have on time after supplying the lubricant, just allow to operate the personnel circulate the machine bed, continuing the work of the interruption.Aim at the " oil over low" signal, handles like this the method can avoid the occurrence the otiose shutting down, reducing the assistance processes time, especially at the time of processing the large molding tool.While designing, we classify the " oil over low" signal to electricity control system" enter to the pause" a signal, adoption" remind the —— the warning the —— pause, prohibition against auto circulate" of reporting to the police and handling。