SU617176A2 - Method of enhancing vibration stability of boring mandrel - Google Patents

Description

one

The invention relates to the field of metalworking, can be used when bore holes and is an improvement of the method for improving the vibration resistance of a boring bar described in the ed. St. No. 224263.

In the main invention of auth. St. No. 224263 describes a method for increasing the vibration resistance of a boring bar, in which the elements of the mandrel are communicated with a constant state by applying a constant force to them in a direction perpendicular to the direction of action of the disturbed force. This provides an increase in the natural frequency of the mandrel.

The known method does not ensure the elimination of damage to the bore hole by the chisel during the withdrawal of the mandrel from the machined part. Therefore, when implementing this method, for example, on finishing boring machines for removing the cutter from the machined surface it is necessary to use additional devices.

The object of the further invention is to ensure the removal of the cutter from the treated surface.

This is achieved in that the line of action applied to the elements of the mandrel is mixed in the direction opposite to the tip of the tool and the drain of the tool is eliminated by removing this force. In this case, the magnitude and offset of the line of action of the applied force relative to the axis of the mandrel is determined by the formula

2EJ.

a-d

PP

EB is the stiffness of the cross section of the mandrel during bending; P is the force applied to the elements of the mandrel in a direction perpendicular to the direction of action of the disturbing force; I is the distance from the flange of the mandrel to the cutter;

Claims (2)

D «:; 0,01-0,02 mm - deflection of the mandrel at the cutter, providing the withdrawal of the mandrel from the machined hole without damage to its surface. FIG. Figure 1 shows a boring mandrel implementing the method; in fig. 2 is a design scheme for determining the dependence of the elastic deflection of the mandrel on the magnitude a of the displacement of the line of action of the force applied to the elements of the mandrel relative to the axis of the mandrel. The mandrel is fastened to the boring head with its flange. In the case of the mandrel with a cutter 2, a blind hole is made, the axis of which is parallel to the axis of the screw and is displaced in the direction opposite to the cutter's vertex. A pin 3 is placed in the hole. In the bore of the housing 1, the package of disc springs 4 acts on the worn chain 3 through the pull 5. The force of the springs 4 is adjusted by the stopper 6. Thus, in this mandrel, the force applied to its elements is displaced in the direction anti-iolol; nominal incisors. During processing, the force developed by the package of springs 4 is transmitted through the rod 3 to the housing 1. In this case, due to the displacement of the rod 3 from the axis of the mandrel, the housing 1 undergoes a tensile stretching, resulting in a bending moment, which provides an elastic deflection of the mandrel in the direction of the cutting tool 2 into the surface to be machined, and stretch the body of the mandrel along its core. The stress state of the onvkp elements provides for an increase in its natural oscillation frequency, and consequently, vibration resistance. After the end of the treatment, the pull 5 is moved to the left with the help of, for example, a hydraulic cylinder (not shown), while compressing the springs 4. The mandrel body 1 is unloaded and, thanks to the elastic forces, is straightened. Thus, the cutter 2 moves away from the machined surface, and the mandrel is led out of the hole without being damaged by the cutter. Thus, the cutter is retracted by removing the reinforcement attached to the mandrel elements. To determine the deflection of the optic at point B, one can use the Mohr integral, which for this scheme has the form MpMi (1) where is the bending moment in the cross section of the mandrel in question, caused by the applied force R. is the bending moment in the cross section of the mandrel from the applied in this section (point B) of a single force directed in the direction of the bend of the mandrel. Substituting the values of Mp in formula (1) and determines PaZdZ 7ii7 - -ryv- w Having solved equation (2) with respect to a, the calculation formula is read. a - - D. (3) I The use of the invention will make it possible to ensure the removal of the cutter from the treated surface by removing the force applied to the elements of the treatment. The invention 1. Method of increasing the vibration resistance of the drain mandrel, and author. St. JMs 224263, characterized in that, in order to tap the machined surface, the force exerted on the mandrel tapes is shifted in direction, opposite to the cutter's angle, and the picker is removed by removing it or. 2. The method according to claim 1, wherein the amount of displacement of the line of applied force relative to the axis of the frame is determined by the formula: 22 / l "-7 D. EJ is the rigidity of the cross section of the mandrel during bending; P is the force applied to the elements of the mandrel in a direction perpendicular to the direction of action of the disturbing force; / is the distance from the flange of the mandrel to the cutter; L 0.01-0.02 mm - deflection of the mandrel at the cutter, which provides the withdrawal of the mandrel from the machined hole without damaging its surface. FIG. one