RU2465986C1 - Spindle assembly - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: spindle assembly includes hollow spindle coaxially located inside bearing assemblies and mounted in thrust ball bearing with preload device for thrust bearings and radial thrust roller bearing, internal ring of which contacts spindle surface along cone surface and pressed by bush coaxial the spindle via nuts. Assembly is equipped by cover with labyrinth sealing located perpendicular spindle axis for pressing internal ring of radial thrust roller bearing and preload device located in spindle front support for compensation of its parts wear. In order to achieve the same technical result the other version of spindle assembly includes hollow spindle coaxially located inside bearing assemblies and mounted in thrust ball bearing with preload device for thrust bearings and radial thrust roller bearing performed in a form of hydrostatic support containing housing in a form of cylindrical bush embracing the spindle that has, at least, three hydraulic radially located elements, each of which consists of coaxially arranged inlet and pocket interacting with spindle via oil wedge, and between housing neck and spindle external surface there are radially arranged outlets made in housing in quantity equal to the quantity of hydraulic radially arranged elements. Pockets are made in a form of cavities, for example round or non-round holes that are connected through throttle and filter with supply main with pump located in oil bath.

EFFECT: increase of coefficient of performance, durability and reliability.

2 cl, 6 dwg

Description

The invention relates to the field of engineering, namely to spindle units. Closest to the claimed object is a spindle assembly comprising a hollow spindle coaxially located inside the bearing assemblies and mounted in a thrust ball bearing with a preload device for thrust bearings and an angular contact roller bearing, the inner ring of which contacts the spindle surface on a conical surface and is compressed coaxially with the spindle by the sleeve by means of nuts (as USSR AS No. 1287978, B23B 19/02, 1987 - prototype).

A disadvantage of the known objects is that the slip pairs due to large losses during sliding have a low efficiency.

A technically achievable result is an increase in efficiency, durability and reliability.

This is achieved by the fact that in a spindle assembly including a hollow spindle coaxially located inside the bearing assemblies and mounted in a thrust ball bearing with a preload device for thrust bearings and an angular contact roller bearing, the inner ring of which contacts the spindle surface on a conical surface and is pressed coaxially with the spindle by the sleeve by means of nuts, the angular contact roller bearing is equipped with a cap with a labyrinth seal located perpendicular to the axis of the spindle a preload for compressing the inner ring of the angular contact roller bearing and a preload device located in the front spindle support to compensate for wear of its parts.

Figure 1 shows a spindle unit, for example a lathe; figure 2 - diagram of the preload ball bearings due to grinding of the ends of the inner rings; figure 3 - installation diagram of spacers between the rings; figure 4 is a diagram of the use of springs, ensuring the constant preload; figure 5 - diagram of the preload due to the deformation of the inner ring when installing it on the conical neck of the spindle in roller bearings with cylindrical rollers; 6 shows the design of a hydrostatic support.

The spindle assembly, for example, a lathe, includes a hollow spindle 8 coaxially located inside the bearing assemblies, mounted in a thrust ball bearing 4 with a preload device 3 for thrust bearings and an angular contact roller bearing, the inner ring 6 of which contacts the surface of the spindle 8 in the conical surface and is tightened on the left side, by the coaxial spindle, by the sleeve 5 by means of nuts 1 and 2, and on the right by a cover 7 with a labyrinth sealed perpendicular to the axis of the spindle by

In the front spindle support, a preload device 3 is provided, which allows you to compensate for the wear of the parts of the spindle assembly.

The preload is carried out in various ways, in angular contact ball bearings and tapered roller bearings with a paired installation, the preload is obtained by adjusting during assembly, and in radial ball bearings - by shifting the inner rings relative to the outer ones. Methods for creating a preload of rolling bearings are as follows: creating a preload of ball bearings due to grinding of the ends of the inner rings (figure 2); installation of spacer sleeves between the rings (figure 3); the use of springs, ensuring the constant preload (figure 4); creating a preload due to deformation of the inner ring when installing it on the conical neck of the spindle in roller bearings with cylindrical rollers (figure 5).

Plain bearings used as spindle bearings are non-adjustable (rarely used), with radial, axial clearance control, hydrostatic (they provide for the supply of oil under pressure in several pockets, from which it is forced out through the gap between the spindle neck and the bearing), hydrodynamic and gas lubricated.

Precision machines use hydrostatic bearings, which create high precision spindle rotation. Their bearing capacity, rigidity and accuracy depend on the size of the clearances, pressure, support pattern.

Figure 6 shows the design of the hydrostatic support, which can replace the angular contact roller bearing of the hollow spindle 8.

The hydrostatic support comprises a housing made in the form of a cylindrical sleeve covering the spindle 8, in which at least three hydraulic, radially arranged elements are made, each of which consists of a coaxially arranged supply hole 10 and a pocket 9 interacting with the spindle 8 by means of an oil wedge . Oil under pressure is fed into the pockets 9 through the hole 10 and is forced out of these pockets through the gap between the neck of the housing and the outer surface of the spindle through the radially arranged outlet openings 11 made in the housing according to the number equal to the number of hydraulic, radially located elements, and then into the reservoir ( not shown in the drawing). Pockets 9 are recesses, for example, made in the form of round or non-circular holes, which, in turn, are connected through a throttle and a filter to the supply line with a pump located in an oil bath (not shown in the drawing).

The spindle unit operates as follows.

Oil under pressure is fed into the pockets 9 through the holes 10. When the spindle 8 is rotated, the oil is forced out of these pockets through the gap between the journal and the bearing and from the hole 11 into the reservoir. With an increase in the external force, which tends to reduce the gap, the oil pressure in the tank increases and the gap is restored. Hydrostatic bearings stabilize friction with lubricant at the lowest rotational speeds.

Medium-loaded spindles are usually made of steel 45 with an improvement (hardening and high tempering). With increased power loads, steel 45 is used with low tempering. For spindles requiring high surface hardness and a viscous core, steel 45 is used with hardening of HDTV and low tempering. The design of the spindles depends on the method of installation of clamping devices on it, for fastening the cutting tool. or workpieces, fitings of drive elements and types of supports used. Spindles, as a rule, are made with a through hole for the passage of the bar. The front ends of the spindles of general purpose machines are standardized.

As bearings of machine spindles, rolling and sliding bearings are used. Spindle units must be of high quality. Therefore, the rolling bearings used in the spindle bearings must be of high accuracy. The choice of the accuracy class of the bearing is determined by the tolerance on the runout of the Executive surfaces of the spindle (tapered bore and base surfaces for installing cartridges, for fastening tools and workpieces), which depends on the required machining accuracy. Usually, more accurate bearings are used in the front support than in the rear.

Claims (2)

1. Spindle assembly comprising a hollow spindle coaxially located inside the bearing assemblies and mounted in a thrust ball bearing with a preload device for thrust bearings and an angular contact roller bearing, the inner ring of which contacts the spindle surface on a tapered surface and is pressed by the axial spindle by the sleeve by nuts, characterized in that it is provided with a cap arranged perpendicular to the axis of the spindle with a labyrinth seal for clamping the inner ring angular contact roller bearing and preload device located in the front spindle support to compensate for wear of its parts. 2. A spindle assembly including a hollow spindle coaxially located inside the bearing assemblies and mounted in a thrust ball bearing with a preload device for thrust bearings and an angular contact bearing, characterized in that the angular contact bearing is made in the form of a hydrostatic bearing containing a housing in in the form of a cylindrical bushing spindle enclosing in which at least three hydraulic, radially arranged elements are made, each of which consists of coaxially arranged the outlet and the pocket interacting with the spindle by means of an oil wedge, and between the neck of the casing and the outer surface of the spindle there are radially located outlet openings made in the casing in a number equal to the number of hydraulic, radially arranged elements, and the pockets are made in the form of recesses, for example, round or non-circular shape, which are connected through a throttle and a filter to the supply line with a pump placed in an oil bath.

Images