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1、对压缩机单螺杆专用加工机床的介绍摘要：本文从四个方面介绍了国内现有单螺杆加工机床的布局和结构，并把优缺点一一列举出来，由于压缩机生产厂的单螺杆加工机床和机床资料对外保密，以上介绍难免有片面、不妥之处，因此仅供单螺杆压缩机生产厂参考。 一、介绍机床的布局压缩机排气量的大小决定了星轮、螺杆直径的大小和啮合中心距的大小，因此螺杆直径的不同，机床的主轴与刀具的回转中心也不同。为满足加工不同直径的螺杆，目前国内单螺杆加工机床的布局大致有以下几种方案。 第一种：机床的主轴与刀具回转中心的中心距为固定式。 机床的主轴与刀具回转中心的中心距为固定式，中心距不可调整。加工几种直径的螺杆就需要几种中心距规格不同的
2、机床。优点：机床的结构简单。缺点：每种机床只能加工一种规格的螺杆，当市场上某种规格的压缩机螺杆需要量大时，造成一台机床加工，其他机床闲置。 第二种：机床的主轴箱为可回转式机床可根据加工螺杆直径的大小在加工前把主轴箱旋转一个角度。这种主轴箱能够回转的机床是对上述第一种机床在使用方法上的改进，与第一种机床的结构基本相同。优点：机床的结构简单，能适应多种规格螺杆的加工。缺点1：主轴箱旋转后主轴回转中心线与刀具回转中心线间的距离不易精确测量。缺点2：主轴箱旋转后主轴前端面与刀具的回转中心线间的距离减少，因此加工较大直径的螺杆受到限制。第三种：机床的主轴箱为横向移动式 主轴箱底部与底座之间布置有矩形滑动
3、导轨，主轴箱移动的方向垂直于主轴回转中心线并垂直于刀具回转中心线。主轴箱的动力通过花键轴传给底座内的刀具进给机构。根据加工螺杆直径的大小，在加工前用手轮丝杠进给机构把主轴箱移动到适当位置，然后用螺钉将主轴箱固定在底座上。主轴箱的移动距离可用光栅尺检测，位置误差0.005mm。采用主轴箱可横向移动的一个机床就可以加工直径95385mm之间任何一种规格的螺杆。由于加工95385mm直径的螺杆，造成主轴前端面与刀具回转中心线间的距离差值过大，因此在实际应用时设计成两种规格的机床，一个机床加工95205mm直径的螺杆，另一个机床加工180385mm直径的螺杆。优点：机床能适应多种规格螺杆的加工，每种规
4、格的螺杆不需要配备相应的加工机床。缺点：机床的结构和机床的装配较前二种机床复杂，机床的造价也较前二种机床高。二、介绍机床的主轴结构机床主轴箱的水平主轴和底座上的立式的主轴精度的高低决定了被加工螺杆的精度，同时螺杆在压缩机中以几千转的速度高速旋转时，精度较差的螺杆会使压缩机产生发热、振动、效率低、磨损快等现象。国内目前现有的单螺杆加工机床主轴结构大致有以下两种方案。第一种：轴承径向游隙不可调的主轴结构主轴前轴承采用1个双列圆柱滚子轴承和两个推力球轴承组合，该主轴使用双列圆柱滚子轴承承受径向切削力，使用两个推力球轴承承受轴向切削力。主轴后轴承一般采用1个双列圆柱滚子轴承或采用1个向心球轴承。这种主
5、轴结构的优点：主轴的加工和装配简单，造价较低。缺点1：由于主轴轴承的径向游隙不可调整，所以主轴精度较差。虽然可以利用轴承的内径和轴径的过盈配合来消除轴承的径向游隙，但每个轴承的内径和径向游隙不是一个固定值，因此设计和加工时很难给准轴径与轴承内径的配合公差。 缺点2：在市场上很难买到国产或进口的C、D级或P4、P5级的推力球轴承，机床生产厂常用普通级轴承替代使用，此举也影响了主轴精度的提高。轴承径向游隙不可调的主轴结构适用于一般精度的普通机床，不适用于对主轴精度要求较高的机床。第二种：轴承径向游隙可调的主轴结构主轴前轴承采用一个P4级圆锥孔的双列圆柱滚子轴承和1个P4级的双列向心推力球轴承组合。
6、该主轴使用圆锥孔的双列圆柱滚子轴承承受径向切削力，使用双列向心推力球轴承承受轴向切削力和部分径向切削力。主轴后轴承一般采用1个P5级圆锥孔的双列圆柱滚子轴承。圆锥孔双列圆柱滚子轴承的内圈和配合轴径均为1：12圆锥，用圆螺母锁紧轴承则使轴承在轴向产生一个位移并使轴承的内圈膨胀，从而达到减少或消除轴承径向游隙的目的。这种主轴结构的优点：主轴精度较高。在主轴前端面230mm直径上测量主轴的端面跳动值为0.010mm。在主轴前端230mm外圆上测量主轴的径向跳动值为0.005mm。第二种结构的主轴精度比第一种主轴精度提高50%左右。这种主轴结构的缺点：主轴的加工工艺较复杂，主轴的装配也需要有经验的工人
7、操作才能使主轴精度达到理想数值。三、刀具进给深度的控制不同直径的螺杆需要加工螺旋槽的深度也不同，螺旋槽的深度从几十毫米到一百多毫米不等，刀具进给机构大约需要旋转进刀几千圈才能完成一个螺杆零件的加工。由于刀具进给机构在刀具旋转的同时还要完成进刀动作，所以一些在普通机床上常用的机械、电气控制切深的方法都不适用于单螺杆加工机床。单螺杆加工机床的刀具进给机构采用以下不同的方法都可以达到控制进刀深度的目的。第一种：摩擦离合器和电气开关控制刀具进给深度它的控制原理是刀具切深增大时刀具进给机构的负载扭距增大，使刀具进给机构传动链中的摩擦离合器打滑，一个机械连杆机构触发电气开关并发出声、光信号提示操作者，此时
8、操作者人工操作断开刀具进给机构的动力。这种控制方法的优点是：控制方法简单及零件加工和操作不受突然断电的影响。缺点是：加工不同直径的螺杆需要调整摩擦离合器压紧碟簧的预紧力。由于每个螺杆材质的密度、硬度存在细微差异及刀具锋利程度也存在差异，因此使这种控制方法的精度不太准确，可能导致螺杆螺旋槽的深度公差过大。第二种：用电磁离合器、编码器组合控制刀具进给深度刀具进给系统中，装有电磁离合器及一对用于检测刀具转动圈数的测速齿轮和一个编码器。它的控制原理是刀具刚接触螺杆表面时手工启动编码器记数开关，记数装置则开始记数，当刀具旋转到事先设定的圈数时也就是达到切削深度时，电磁离合器自动断开刀具进给的动力并发出声
9、、光信号提示操作者零件已加工完毕。该检测装置通过数显表显示进给圈数或进给量。电磁离合器脱开后，刀具只随立轴旋转并无进给运动。这种控制方法的优点是：螺杆螺旋槽的深度公差控制较准确，由于有数显表显示要加工的深度或圈数和已加工的深度或圈数，在操作上也很直观和方便。缺点是：机床的电气控制较复杂同时这种控制方法在零件加工时如果厂区突然断电，事先设定的数据会丢失。如果在电气控制中加入蓄电池，使之在断电维初期维持检测装置的工作，上述问题就可以得到解决。四、 齿轮传动间隙的控制单螺杆加工机床在加工螺杆时，由于螺旋槽是在刀具旋转和工件旋转的合成作用下完成加工的。在刚切入工件时刀具在旋转的切向方向上受到的走刀抗力
10、较大，刀具在将要切出工件时在螺旋槽的作用下，刀具在旋转的切向方向上受到的走刀抗较小，甚至是受到工件螺旋槽的推力。由于存在着机床箱体孔加工、齿轮加工等各种误差，刀具旋转轴的传动间隙过大，俗称旷量大。检测传动间隙过大的方法是将动力输入轴固定并左右旋转晃动输出轴，如果是用常规的传动结构设计制造机床，输出轴的传动间隙摆角在十几度到几十度。传动间隙过大造成螺杆的螺旋槽加工表面有明显的接刀痕，从而影响了螺杆的加工精度。机床在装配完成后刀具旋转轴的传动间隙过大，实际上是齿轮受各种误差的影响，造成齿轮侧隙的过大。机床机械传动中的齿轮加工不管是采用几级精度的，设计者考虑到齿轮的制造误差、箱体中心距加工误差、温度
11、变化、润滑油膜厚度、装配误差等因素，机床传动设计必须保证齿轮传动留有一定的侧隙，侧隙的大小决定了齿轮齿厚公差的大小。单螺杆加工机床的主传动结构有区别于其他机床的特殊性。为减小或得到合理的传动间隙目前单螺杆加工机床常采用以下两种办法。第一种：在输出轴上安装抱闸在刀具旋转输出轴外圆径向对称位置装有抱闸，抱闸前端顶住刀具旋转输出轴的外圆，抱闸为弹簧预紧。抱闸的工作原理是靠抱闸产生的摩擦力来增大输出轴阻尼，降低轴的旋转灵敏度。优点是：抱闸结构简单并且不改变原有机床结构，这种方法间接地达到了减少传动间隙的目的，在实际应用中有一定的效果。缺点1：弹簧预紧的抱闸由于对刀具输出轴外圆施加了较大径向力，实际上增
12、大了机床的负载扭距，造成电机功率增大，同时齿轮、轴承磨损加快。缺点2：弹簧预紧的抱闸由于对刀具输出轴外圆施加了较大径向力可能对刀具输出轴的几何精度造成负面影响。第二种：双齿轮传动把主传动中所有主动齿轮的齿宽增加1/31/2。把所有被动齿轮做成两层结构，一层齿轮是原有齿轮，另一层是用来减少传动间隙的齿轮，它的齿宽约是原有齿轮齿宽的1/31/2。用数个螺钉将两个齿轮毛坯安装在一起并拧死在再制齿。制齿后将齿轮装在机床传动轴上，松开齿轮固定螺钉，将约1/31/2齿宽的齿轮朝着该齿轮旋转运动相反的方向转动齿轮，转动角度的大小以齿轮长期工作、最大温升时齿轮侧隙大于零。双齿轮传动的工作原理是用双齿轮中较宽的
13、齿轮传递动力，较窄的齿轮起到减少传动间隙的作用。沿着轴心线看调整后的两层齿轮的齿形有微量错位，结构优点：根据齿轮的实际制造误差、箱体中心距实际加工误差、等因素，调整齿轮的传动间隙使之在一个合理的范围之内，与抱闸结构相比更合理、适用。结构缺点：由于齿轮齿宽增加，传动轴的轴向尺寸加大，并且箱体上还要留有齿轮调整用的窗口，这种方法只适用于新设计的机床并且增加了机床的制造成本。结论：本文从四个方面介绍了国内现有单螺杆加工机床的布局和结构，并把优缺点一一列举出来，由于压缩机生产厂的单螺杆加工机床和机床资料对外保密，以上介绍难免有片面、不妥之处，因此仅供单螺杆压缩机生产厂参考。Dedicated to t
14、he single screw compressor machine updated the Introduction Abstract: This paper describes four areas from the existing single-screw machine layout and structure, and put out the advantages and disadvantages of the list, because of the compressor plant single-screw machine tools and machine tool ext
15、ernal Security information, the above introduction there is inevitably one-sided and wrong, and are therefore single-screw compressor for the production of reference works. First, introduce the layout of machine tools Decide the size of the compressor displacement of the stars round, screw diameter,
16、 mesh size and the size of the center distance, so different in diameter screw, machine tool spindle and the rotary center are also different. To meet the processing of different diameter screw, single screw Currently the layout of machine tools in general there are several options. The first is: ma
17、chine tool rotary tool spindle center and the center distance for the fixed Machine tool rotary tool spindle center and the center distance for the fixed, can not adjust the center distance. Processing of several of the screw diameter on the center distance required several different specifications
18、of the machine. Advantages: simple structure of the machine. Disadvantage: each machine can only process a specification of the screw, when the market on a certain specification requirements when the screw compressor, resulting in a machine, other machine idle. The second: the machine tool spindle b
19、ox for rotary Processing screw machine according to the size of the diameter at the processing before a point of rotating spindle box. Spindle box that the machine can turn on a machine at the above-mentioned article on the use of the improvements, with the first structure of a machine tool is basic
20、ally the same. Advantages: the structure of machine tool easy to adapt to a variety of specifications of the processing screw. One disadvantage: after the rotating spindle box and the tool spindle turning center line distance between the center line of accurate measurement difficult. The other disad
21、vantage: after the rotating spindle box and the front surface of the rotary cutter centerline distance between the reduction of the larger diameter of the screw processing is limited. The third: the machine tool spindle box for horizontal mobile Box at the bottom of the spindle and the base there is
22、 arranged between the rectangular sliding rail, spindle box perpendicular to the direction of movement of spindle centerline and perpendicular to the centerline of the tool rotation. Through the power of the spindle box spline shaft to the base of the tool feed mechanism. Screw diameter, according t
23、o the size of the processing in the processing of the previous round by hand to the body put into the screw spindle box moved to the appropriate location, and then screw the spindle box on a fixed base. Spindle box available from the mobile Grating detection, position error 0.005mm. Horizontal spind
24、le box can be used as a mobile machine can process diameter 95 385mm any kind between the screw specifications. 95 385mm processing because of the diameter of the screw, causing the front surface and the tool spindle rotation the distance between the center line of the margin is too large, the actua
25、l application in the design specifications of the machine into two, a 95 205mm machine screw diameter Another 180 385mm machine screw diameter. Advantages: a variety of tools to adapt to the specifications of the processing screw, each screw specifications need not be provided with the appropriate m
26、achine tools. Disadvantage: the structure of machine tools and machine tool assembly of the two kinds of more complex machine tools, machine tools than the cost of two kinds of machine tools before the high. Second, introduce the structure of machine tool spindle The level of machine tool spindle bo
27、x on the main axis and the base of the vertical axis determines the degree of precision was the precision screw machining, at the same time screw compressor at a speed of thousands of high-speed rotary switch, the accuracy of the screw will be less so that the compressor have a fever, vibration, low
28、 efficiency, such as wear and tear situation quickly. Currently available single-screw machine spindle structure of the program has the following two. The first is: bearing radial clearance is not adjustable spindle structure Before spindle bearing out the use of one pairs of cylindrical roller bear
29、ings and thrust ball bearing combination of both, the main use of double row cylindrical roller bearings under radial cutting force, the use of two ball bearings to bear axial thrust cutting force. After the general adoption of the spindle bearings out one pairs of cylindrical roller bearings or a b
30、all bearing to the heart. Main advantages of this structure: the main axis of the processing and assembly of simple, low cost. One disadvantage: because the main axis of the radial bearing clearance can not be adjusted so poor precision spindle. Although the use of bearings and shaft diameter fit to
31、 eliminate the radial bearing clearance, but each bearing diameter and radial clearance is not a fixed value, so it is difficult to design and processing to the quasi-axial-radial and bearings with bore tolerances. The other disadvantage: it is very difficult to buy in the market of domestically pro
32、duced or imported, C, D or P4, P5 class thrust ball bearings, machine tool manufacturing plant commonly used alternative to the use of ordinary class bearings, which also affected the accuracy of the enhance spindle. Bearing radial clearance adjustable spindle structure do not apply to the general a
33、ccuracy of the general machine tools, does not apply to require a higher accuracy of the spindle of machine tools. The second: the radial bearing clearance adjustable spindle structure Before the adoption of a spindle bearing P4 class of double row tapered hole cylindrical roller bearings and a P4-c
34、lass double row ball bearing thrust to the combination of heart. The use of the spindle hole of the double row tapered cylindrical roller bearings under radial cutting force, the use of double row ball bearing thrust to the heart to bear part of the axial and radial cutting force cutting force. Spin
35、dle bearings generally used after a P5 class of double row tapered hole cylindrical roller bearings. Double row tapered hole cylindrical roller bearings with inner ring and shaft are tapered 1:12, bearing lock nut with a round led a bearing in the axial displacement of the inner ring bearings and ex
36、pansion, to reduce or eliminate Bearing radial clearance purposes. Main structure of such advantages: high precision spindle. At the front spindle diameter 230mm noodle on the end measuring spindle Beat value of 0.010mm. 230mm cylindrical spindle at the front end on the radial axis measurement value
37、 of Beat 0.005mm. The second structure of the spindle of precision spindle accuracy than the first about 50% improves. Main disadvantage of this structure: The principal axis of the more complicated process, the spindle assembly also has the experience necessary to make the workers to operate the sp
38、indle achieve the desired numerical accuracy. Third, the depth of the tool feed control Required different processing screw diameter spiral groove depth is also different from the depth of the spiral groove mm from dozens to more than 100 millimeters range around the tool into the institutions requi
39、red to feed the thousands of ring rotation in order to achieve a screw machining. Feed because of the tool in the tool rotating at the same time achieve motion feed, so on a number of general machine tools used in mechanical, electrical control method of depth of cut does not apply to single-screw m
40、achine. Single screw machine tools give agencies into the following different methods can be feed to control the depth of purpose. The first is: friction clutch and electrical switches to control the depth of the tool feed Its principle is to control depth of cut increases the tool cutter feed mecha
41、nism increases the load torque so that the tool feeding mechanism of the friction transmission chain slipping clutch, a mechanical linkage concurrent silent trigger electrical switches, optical signal prompted operator, when manual operator to disconnect the tool into the power sector. The advantage
42、s of this control method are: the control method is simple and spare parts processing and operational power from the impact of a sudden. Disadvantages are: processing of different diameter screw to adjust the clutch friction discs pressed the preload spring. Material because of the density of each s
43、crew, and the hardness of the existence of subtle differences in the degree of cutting tools sharp differences exist, thus the accuracy of this control method was not too accurate, may lead to screw spiral groove depth tolerance is too large. The second: use of an electromagnetic clutch, encoder con
44、trol tool into the mix to the depth of Tool feed system, equipped with electromagnetic clutch and a tool for detecting the number of rotating ring gear and a gun encoder. It is a tool of control principle just contact hand screw surface encoder to start counting switch, then start counting device, w
45、hen the rotary tool to pre-set number of laps when the cutting depth is reached, the electromagnetic clutch automatic off open to the power tool into the concurrent silent, optical signal parts prompted the operator has finished processing. The detection device through the digital display shows the
46、number of feed circles or feed. Torn off and the electromagnetic clutch, the tool does not only into the rotation with the vertical shaft to the sport. The advantages of this control method are: the depth of the spiral groove screw tolerance control more accurate, because of several significant tabl
47、e shows the depth of processing, or want a few laps and the depth of processing or circle the number of operations is also very intuitive and user-friendly. Disadvantage are: electrical control of machine tools at the same time more complex parts of this control method at the processing plant, if a
48、sudden power failure, the prior data set will be lost. If you add in the electrical control of the battery to power at the early-dimensional detection devices to maintain the job, the problem can be resolved.Four, the control gear drive space Single screw machine screw in the processing, due to the spiral groove in the rotary tool and the workplace rotation to complete the