CNC Spring End Grinding Machines Using The Slope Principle
CNC Spring End Grinding Machines Using the slope principle
Ball screw nut mechanism is the screw and nut between the continuous loading of multiple particles and other balls, as shown in Figure 1, when the screw or nut rotation, the ball rolling along the spiral groove, on the screw After rolling a few turns, through the return guide device, one by one roll back between the screw and nut, constitute a closed loop. According to the ball of the cycle, the current can be divided into two categories: when the ball in the loop is always in contact with the screw called the internal circulation, from the screw called the outer loop. Ball of the circular race can be divided into two parts of the inner raceway and outer raceway, the inner race by the screw and nut part of the screw. As the ball caught in the middle, to maintain the two have a strict relationship between the location. The accuracy of the inner raceway and the cross-section formation have great influence on the bearing capacity and transmission accuracy of the screw. The outer raceway is the ball off and return the raceway of the channel, so his spiral direction just opposite to the inner raceway, if the inner raceway is the right side of the outer raceway is left. The shape of the outer raceway is correct, it will affect the ball screw rotation flexibility and efficiency, poor handling will produce "card" beads (that is, the ball does not turn) phenomenon, so that the ball friction into sliding friction, greatly reducing the ball The performance of the screw.
If the ball in the same nut only one cycle raceway read, called the single row; there are two races called double; more than two or more called multi-column. In order to maintain the ball in the raceway in the fluency, the general requirements of a single row of roller race in the circle of the number of work cycles no more than three and a half, the number of balls not more than 150 tablets. If the number of work cycles need more than three and a half times, it should be made of multiple columns (of course, within three and a half years, due to the need to also use multiple columns), but generally better not more than three, otherwise the nut Axial size is too large.
In addition to the swing feed mechanism, the other feed mechanism almost all by the screw nut mechanism to drive the wheel frame, so it is the feed mechanism of one of the main transmission. Screw nut mechanism is not only used in the feed mechanism, but also widely used in grinders and other machine parts, the following to specifically introduce the screw nut mechanism of the body, design and manufacturing. The screw nut mechanism has the following characteristics:
(1) The screw nut is a mechanism that turns the rotary motion into a linear motion. The shape of the motion is shown in the figure, where Figures a and b are the two most useful forms in the screw nut mechanism. When the screw is rotated, the nut (or screw) moves one or several pitch S; Figure 5 is a differential screw nut mechanism. Fig. 5 is a differential screw nut mechanism. Fig. 5 shows the structure of the nut.
As the screw nut is generally very small, even if the screw speed is very high, the nut is not moving the amount of large, so can achieve a large reduction ratio. The screw nut mechanism can greatly shorten the transmission chain of the speed reduction mechanism. In addition, because the screw nut can achieve a higher transmission accuracy, if equipped with a pitch correction device, can be used for precision positioning, fixed precision up to 0.001 mm.
(2) screw nut is the use of inclined principle of the transmission mechanism, with a smaller torque transmission screw, which can get a larger axial traction. When the screw screw angle is small, the body also has a self-locking effect. There are two kinds of sliding screw nuts used in the grinding machine. Fig. 1-a is a semi-nut structure. The advantage is simple structure and easy assembly. The gap between the screw and the nut can only be adjusted. The disadvantage is that the single side of the screw by the radial force, easy to cause bending deformation, compared with the whole nut contact poor rigidity. However, due to the grinding machine in the horizontal feed mechanism of the screw nut force is small, so the impact of the drive so the general accuracy of the cylindrical grinding machine feed mechanism, can be used semi-nut structure. Full nut structure, good contact rigidity, high transmission accuracy, but the assembly adjustment than the former trouble.