Cylindrical Grinder feed hand wheel force factors

手轮力的轻便是进给系统达掉了呢? 现就以下几个方面进行探讨。">Cylindrical Grinder Feed handwheel force feeding system of lightweight is out of it ? Now be discussed on the following aspects. Steady hand turn , Huai indeed fundamental guarantee. We measured瑞士斯图德(s tud er) company RHU precision cylindrical grinder feed handwheel force 2 kgf, Japan Iron Works G CU fear cylindrical grinder feed hand wheel force 3 kgf. And with specifications similar to those of MG 1 4 3 2 high-precision cylindrical grinder force feed hand wheel there is a huge gap. For referral decision cylindrical grinder feed hand wheel force overweight problem , we MG 1 4 3 2 high-precision cylindrical grinder feed system made ​​some theoretical discussion and various comparison test , analyze the impact feed hand various factors wheel force .
        Given: wheel frame and weight of the carriage G = 50 0 kgf, fast tanks and brake cylinder working pressure p = 10 kgf / cm Z, screw pitch diameter D in = 53.5 mm, toothed half-width a = 1 5. Hand Second hand wheel diameter D 2 50 mm; rail rolling friction coefficient f = 0.01. * Handwheel force calculated as 1.07 "kgf. Then start if the inertia of the entire system , including the calculation , only Z k gf. , But the measured results , the feed handwheel force has reached 4 ~ 5 k gf. Such a big drive where losses are consumed it? now be discussed on the following aspects.
        A feed guide in the form of impact force feed hand wheel first is to overcome the frictional resistance of the feed rails ( corpse guide ) .
        Generally believed that changes in the form of rail feed handwheel , such as from sliding into rolling , can significantly alter the force feed hand wheel size. We MG1432 form feed rails made ​​various tests and measurements with hydraulic booster shot starting axial traction wheel wheel rack system . From these data , the required axial traction rolling guide about one tenth and hydrostatic unloading plastic guide rails . According to the measured axial pull bow ! Force can calculate the theoretical tools to overcome the force of the hand wheel rail friction value and the actual value required . From the data in the table show that the form of rail rolling round opponents force effects are minimal. Although a variety of sliding coefficient of friction than the rolling guide rail large nearly tenfold , but the need to increase the feed handwheel force is only about 1 kgf. It only measured force feed hand wheel 1/4 to 1/5.
        Visible, hand wheel friction forces are not multiples of the system increases . So , whether it is changed from sliding or rolling guide rail rolling guide to the plastic rails , can not force the feed handwheel significant changes. Thus, the form is not a major determinant of the rail feed hand wheel force .
        Second, the impact force of the brake cylinder in order to eliminate the gap between the screw and the nut , increase the feed stiffness, etc. is often used to brake cylinder tensioning device in the system. Figure 1 brake cylinder push rod 8 the action of the oil under pressure into the right side of the carriage 7 . This gives the feed system adds an additional axial pull bow ! Force , which directly increases the force feed hand wheel . In addition, the brake cylinder force feed point on the surface to produce a moving rail subversive moment , it only makes contact with the screw , nut adverse effects , but also adds an axial pressure on the screw , so that the two screw end support of friction increase, thus additionally increasing the feed hand wheel force . Therefore, the design should be possible to force the position brake cylinder arrangement point in the plane of the rail surface . Such as the use of hydraulic double nut device can better influence referral decisions brake cylinder force , the feed handwheel force reduced to a certain extent . To arrive at the impact force opponents wheel brake cylinder force , we measured the time the feed system when there is no brake cylinder brake cylinder force and the force needed to force feed hand wheel . Data in the table than the theoretical calculations to be smaller, especially in the smaller cylinder working pressure less difference . Seen in the brake cylinder at a reasonable choice premise force magnitude and position , since the brake cylinder to increase the force of the hand wheel force feed before feeding system representing the force of a hand wheel / 5 . So, do not think brake cylinder force is a major factor affecting the feed handwheel force .
        Third, the transmission opponents Structure of the feed system feeding system is an invisible force round effects . After applying pressure , especially in the fast- cylinder oil , the impact of the state in which the entire feed mechanism to force the hand wheel designed to bring often not given enough attention. Before the test , in order to exclude the impact of rail friction and brake cylinder force , the first wheel frame and slide 7 dismantled. Then five years in the fast pass into the cylinder pressure oil at this time, quickly left the screw 3 .
        Hand wheel and the front end of the ball contacts the end surface of the plug 1, the piston 4 and the right ball contact . Screw in the cylinder 3 is subjected to extrusion pressure . In this case, the feed handwheel force with increasing work pressure increases , and this force exceeds the sum of the handwheel feed hand wheel rail friction force and the force needed to brake cylinder .
        In order to distinguish where the resistance is generated , we will point the hydraulic booster of the afterburner on the pitch circle of the gear screw ( slightly lower than 5 m ln). The screw were measured starting force required . From Table 3 , when the working pressure of 1 0 kgf / cm Z, the starting torque of the screw :. M = solid wire ( 12 a 4 5) X 5 5 = 4 1 2 5 kgf / mm If the theoretical calculation due to work pressure, so being 3 8 1 kgf screw extrusion pressure . At both ends of the ball screw head contact than the pressure at large , but in fact is not the point of contact with a round face contact with a 4 mm . Thus , calculated to overcome the friction screw starting torque 30 4 kgf / mm. The difference between the measured value and the calculated value (l os. Skgf / mm) is the radial ends of the screw bearing against the sliding friction torque required action of the oil under pressure .
        Obviously , in order to overcome such great frictional torque when the required feed force together with the hand wheel load ( i.e. p = 0) the torque required to overcome the friction feed handwheel force , as high as a calculated value . 76k gf. By comparing the measured and calculated data indicate that : ¹ nearly half handwheel force feed screw completely consumed in both ends of the friction surface , the less work pressure , the less friction loss . Therefore, in order to reduce the force feed hand wheel , it is necessary to reduce friction losses screw end face. That is, to ensure that appropriate reduction of the fuel tank quickly fast forward thrust when wheel frame . However, the hydraulic system pressure to affect the performance table for force variation and the brake cylinder , thus reducing the working pressure can not be reduced fast way to the cylinder thrust ; Meanwhile, in order to ensure the transmission of the original structure of the same form , we will rapid change of the differential cylinder of the cylinder structure . Front left oil chamber when the machine is working oil pressure remains constant ; just fast forward when the wheel frame , the right to return the oil to the oil pressure oil chamber . Since around the piston effective area ranging from the oil chamber , the chamber is larger than the left and right chambers to achieve rapid feed wheel frame . In this case , working pressure P = 1 0 kgf / time em Z, screw extrusion pressure suffered 2 2 7 kgf, lower than the original 1 5 4 kgf. In addition, the axial ends of the ball screw heads to slide bearing rolling bearing .
        Right of using a pair of thrust bearings , left in the block with a thrust bearing head . Thus , without changing the original premise of the cylinder diameter , can greatly reduce exposure to screw extrusion pressure , increasing the handwheel wheel frame backward thrust , not only the rapidly receding faster wheel frame , and can be reduced as much as possible small gate thrust cylinders to meet the requirements to overcome the frictional resistance of the feed rails need , as a result the force feed handwheel can achieve lightweight . After this modification , in the case of the removal of the wheel frame and slide , the measured force feed hand wheel of the system ( see Table 4 ) , feed hand wheel force than the original structure is much smaller, radically reducing the overall feed the friction loss of the system. In addition, we replaced the original plastic with a rolling guide rail , they need handwheel force even smaller. This further proves the friction loss at both ends of the system is exposed screw extrusion pressure is the main factor causing the feed handwheel force impact. As regards the system of feed gear friction loss , the friction loss of the drive screw nut , etc. , is also a certain influence on the force feed hand wheel , and in a transmission structure is inevitable. Therefore, these factors should influence the design of the structure , given enough attention.
        Fourth, the influence of the assembly adjustment handwheel assembly process , since the error and shall not be deemed part of the adjustment processing , the system will bring a large friction loss . MG feeding system 1432 , the half- nut and screw bad ; sector gear and the end face bearing supporting hole is not perpendicular to the screw ; hand front wheel misalignment is supported , around the screw shaft is supported different axes and other factors , the feed will greatly increase the power of the hand wheel . In the assembly adjustment, it should be noted : with the gap between the screw and half nut should be 0.08 ~ 0.12mm, and a fixed plane and bus half screw nut should be parallel with the feed rails ; rapid cylinder piston and cylinder body with the gap is not too large , so as not to affect the feed screw around with the support rails are not parallel ; screw from the right side of the two thrust bearing nut after tightening workers should ensure that the piston on the screw rotation flexibility, and axial movement should be less than 0.01mm; ¼ brake cylinder plunger 8 and v -rail should be parallel with the cylinder with the gap should be in the range of 0.01 ~ 0.015mm .
        In addition, the positioning column 9 loaded slide 7, the surface should be positioned vertically with ejector 8 . All of these adjustments friction generated by the assembly , not the system 's inherent factors , it is man-made, are completely avoidable. Only carefully assembled , in order to reduce the impact on the feed assembly adjustment handwheel force .