SU1565594A1 - Boring bar for working deep holes - Google Patents

Abstract

The invention relates to metal working and is intended for the rough stretching of deep, precise holes. The aim of the invention is to increase the stiffness of the head by eliminating the gaps of the coupling body - guides. Boring bar consists of a body 1 with a cutting block, guides 6 and a spring-loaded wedge 8, made in a cross-section in the shape of a rhombus. The boring bar is inserted into the filling device before stretching. Thus, the guides 6 receive the desired tension. In the process of cutting, the action of normal forces on the conical chips of the diamond pad 5 of the guides 6 will ensure their convergence within the limits of the guaranteed gaps. As a result, the pads 5 of the guides 6 will be reliably pressed against the side surfaces of the grooves in which they are placed. 4 il.

Description

The invention relates to metalworking and is intended for rough boring of deep precise holes !.

The aim of the invention is to increase the accuracy of hole machining by increasing the rigidity of the head by eliminating technological clearances of the housing-guide interface.

Figure 1 presents the proposed boring bar, a longitudinal section; figure 2 is the same, a view from the front end; in Fig.3 is a section aa in Fig.1; figure 4 - the position of the elements of the boring bar and the forces acting on them in the work.

The boring bar for processing deep holes consists of a housing 1, in the front of which a cut-off finger 2 is pressed in, which serves to install the cutting unit 3, the latter is fixed with screws 4 in a stationary state relative to the boring bar housing 1. In the housing 1 of the boring bar, four through longitudinal grooves are made for placing the blocks 5 with guides 6 “The blocks 5 'with the guides b are kept from falling out by special plates 7.' In the central hole of the housing 1 of the boring bar there is a wedge 8, with the conical bevels of the blocks 5 interacting with its faces, what ensures reliable adjustment of the guides 6 to the required size. To increase the stiffness of the mating head housing. - guides, determined primarily by the presence of a technological gap between the body 1 and the block 5, the edges of the wedge 8 are made so that in the cross section they form a rhombus with angles different from the straight line. With this configuration of the wedge 8, its faces are inclined with an inclination K of the longitudinal groove axis . The edges of the wedge, interacting with the conical bevels of the blocks 5, eliminate the existing gap so that the head housing is-. sandwiched between adjacent blocks 5.

The end surface of the wedge 8 is in contact with the slotted spring 9, Two nuts 10 are used to preload the spring 9,

Borshtanga for processing deep holes works by the method of dividing the thickness of the slice. As follows.

Before entering the boring bar into the filling hole, the guides 6 are adjusted to a size exceeding the diameter on the calibrating edges of the cutting unit 3. By the amount of interference determined by the cutting forces during boring, the corners of the wedge 8 and the force characteristic of the spring 9. The rotation of the nut 10 causes compression of the spring 9 and axial movement of the wedge 8, which provides radial movement of the blocks 5 with guides 6, while the housing, the heads are sandwiched between adjacent blocks and cannot move relative to the guides in the process e work.

Before boring the boring bar is introduced into the filling device. The diameter of the conductor sleeve of the filling device is equal to the diametric size along the calibrating edges of the cutting unit 3. Thus, the guides 6 receive the required interference and the boring bar is reliably centered in the filling device. In the process, the boring bar passes into the machined hole, where working with interference fit guides 6 also ensure its accurate basing. The action of normal forces and Ν on the conical bevels of the blocks 5, respectively, ensures their mutual rapprochement, within the limits of the guaranteed gaps. As a result, the pads 5 are reliably pressed against the lateral surfaces of the X grooves in which they are located.Likewise, it can be shown that under the action of normal forces _{1 3} and 1C on the conical bevels of the corresponding blocks 5, they also come closer and are pressed to the lateral surfaces of the Υ grooves in which they are placed.

Thus, the presence of a certain inclination of the edges of the wedge to the axis of the longitudinal grooves allows you to choose guaranteed gaps in the pairing of the housing - guides in a certain. ... direction. The presence of a rhombic transverse configuration of the Wedge ensures rapprochement within the gaps of adjacent blocks with guides, due to which the head housing is clamped between them. In the proposed design, the magnitude of the friction force T of the guides is significantly less than the radial component of the force of action N _{2 of the} wedge, pressing the pads to the side surfaces of the grooves in which they are placed. The ratio of the indicated forces is determined by the tilt angles (90 ^σ ~ о () of the side surfaces of the wedge to the axis of the longitudinal grooves. For the normal operation of the mechanism, the angle <7 must be chosen from the condition? H> (where φ is the angle of friction of the contacting faces), always Τ.

increase accuracy increase hard — in cross-section

1,565,594 6

Claims (1)

The formulas and inventions of Borshtang for processing deep holes, comprising a housing with ra-. . dially movable guides and spring loaded wedge mounted to cooperate with guides of aphids h ^x ayuschayasya in that, in order to process due to minute, the wedge is in the shape of a rhombus. ·. Editor I. Gornaya