CZ308860B6 - Mechanism for adjusting segments of a segment radial bearing - Google Patents

Abstract

A mechanism for adjusting the segments (2) of a segment radial bearing formed by a sliding spring-loaded support (4) in a radial bore (5) in the bearing body (1) or in the machine body, which rests on the segment (2) at one end. The stroke of the support (4) at its other end is defined by a bushing (6) screwed into the hole (5) of the bearing housing (1) or the machine housing. A protrusion (8) of the other end of the support (4) terminates in the housing (6), terminated by a stop (9) to define the stroke of the resilient element which rests on the support (4) and the housing (6).

Description

Segment bearings are characterized by good dynamic properties; they are able to ensure the stability of the rotor in most real operating conditions. In order to be able to form a sufficiently load-bearing film on the sliding surface of the segment even with a very low viscosity of the process medium, these bearings have only three segments, in contrast to conventional hydrodynamic bearings.

Plain bearings are known in which the segments are tilted by rolling on their outer cylindrical surface. Although there is no wear during rolling, the production technology is demanding, because the centers of curvature of the inner and outer cylindrical surfaces of the segment are different. Especially with smaller values of bearing clearance, it is very difficult to observe the required tolerances. To this end, such segments cannot tilt in the transverse direction.

This problem is solved by bearings with segments housed in a housing with backlash and supported resilient elements.

CZ 300719 discloses a sliding radial bearing with tilting segments, which consists of a bearing housing, tilting segments, adjusting pins with nuts. In the bearing, one end of the adjusting pins is arranged in the tilting segment and the other end in the bearing housing. Between the segments and the bearing body, elastic delimiting elements are inserted - flat springs, through which adjusting pins provided with a collar abutting in the direction from the center of the bearing to the elastic delimiting element are threaded. The disadvantage of this solution is that it substantially limits the possibility of tilting the segment, because due to the deformation of the resilient delimiting element, the segment can come into contact with the delimiting element at two points.

CZ 304852 describes a sliding radial bearing of essentially the same composition as the previous document. Holes for set screws are made in the bearing housing, and axial recesses are made in the segments on the side adjacent to the bearing housing. A rounded insert is arranged in each of them, the insert having a smaller width in longitudinal section than the width of the recess. Threaded holes are made in the inserts coaxial with the holes in the bearing housing. Adjusting screws are inserted into the threaded holes in the inserts and into the holes in the bearing body, by means of which the degree of abutment of the inserts on the flexible delimiting elements in the direction from the center of the bearing is set. In this solution, the segment rolls with its rounding after rounding of the insert, which has a smaller radius than the rounding of the segment. When adjusting the position of the segment, and thus the play in the bearing, the insert can rotate about the axis of the adjusting screw, which results in a corresponding rotation of the segment with subsequent contact of the sliding surface of the segment with the shaft.

CZ 306630 describes a solution in which the tilted segments are rotatably mounted on pins inserted into calipers, which are fastened to the ends of adjusting screws mounted in the bearing housing by means of nuts. Arranged between the yokes and the bearing housing are flat spring elements through which the adjusting screws pass and the pressure of which can be adjusted by the adjusting screws.

A common disadvantage of said bearings is the placement of the resilient elements so that they are immediately

-1 CZ 308860 B6 touch segments. They are thus exposed to high temperatures, which during operation can adversely affect their mechanical properties and the life of the entire bearing.

This problem does not occur with the plain bearing described in CS 230535, where the pivot segments are mounted on pins mounted in recesses of radial supports mounted in the bearing housing, one of the supports resting on a resilient element at the end facing away from the heat source. However, the design of this bearing is relatively complex and demanding on production accuracy. The lower segments are mounted on rigid supports, so that in the event of an impact load, eg rapid changes in position, the segments may come into contact with the rotor.

DE 102014226807 discloses a foil segment bearing provided with mechanisms for adjusting the gap between the inner surface of the segments and the shaft. The adjusting mechanism consists of a pin, the axial position of which is influenced by a hard spring. It is clear from the drawing that the pin and the spring are accommodated in a blind bore guided from the inside of the bearing, the pin passing through a hole in the bottom and the spring resting on the bottom. The cylindrical head of the pin aligns with the cylindrical cavity in the segment.

All the bearings described above are difficult to manufacture and especially to assemble, which requires the presence of the human factor and are therefore not suitable for mass production.

The object of the invention is to provide a radial segment bearing with such an arrangement which, while retaining the advantages of known bearings, substantially reduces production, in particular assembly, costs.

The essence of the invention

This task is fulfilled by a mechanism for adjusting the segments of a segment radial bearing formed by a spring-loaded support slidably mounted in a radial hole in the bearing body or in the machine body, which rests on the segment at one end. The essence of the mechanism lies in the fact that the stroke of the support at its other end is defined by a sleeve screwed into the bore of the bearing body or machine body.

To define the circumferential and axial position of the segment, a pin engages with play in the recess in the segment from the first end of the support.

For better guidance of the support, a guide can also be formed for the support in the housing.

The resilient element may be a spring.

The stop can be screwed onto the protrusion.

Explanation of drawings

The invention will be further elucidated by means of the drawing, in which Fig. 1 is a side view of a further described embodiment of a segment bearing according to the invention, Fig. 2 is a plan view A-A according to Fig. 1 and Fig. 3 a detail B according to Fig. 2.

Examples of embodiments of the invention

The segmented radial bearing according to FIGS. 1 to 3 is formed by a bearing body 1 in which three segments 2 surrounding the shaft 3 are accommodated. 4 housed in radial holes 5 in the bearing housing 1. The support 4 is then mounted in the radial opening 5 of the body 1

- 2 CZ 308860 B6 bearings slidably, abutting the segment 2 at one end. At its other end, the support 4 is guided in a housing 6, which also defines its stroke in the radial direction. The housing 6 is fixed in the opening 5 of the body 1; in the example shown, it is screwed into it. In other embodiments, the housing 6 may be fixed in another manner after being set in the desired position in the opening 5. An elastic element is inserted between the supports 4 and 5 by the housing 6 - in the example shown a coil spring 7. In other embodiments, another elastic element, e.g. a rubber block, can perform the same function. A protrusion 8 of the other end of the support terminates in the housing 6, terminated by a stop 9, which defines the stroke of the spring 7, if the assembly: support 4, housing 6, spring 7 is located outside the bearing housing 1. In the example shown, the stop 9 is screwed onto the projection 8, in other embodiments it can be fastened in another way.

To define the circumferential and axial position of the segment 2, a pin 10 engages with the play in the bore in the segment 2 from the first end of the support 4.

Assembly: the support 4, the housing 6, the spring 7 and the stop 9 represent one autonomous assembly unit, which can be made in operation outside the bearing body 1 and subsequently screwed or fixed into it. This represents a significant time saving compared to assembling substantially more complex known means for locating bearing segments.

Claims (5)

A mechanism for adjusting the segments (2) of a segment radial bearing, formed by a spring-loaded support (4) slidably mounted in a radial bore (5) in the bearing housing (1) or in the machine housing, which rests on the segment (2) at one end, characterized by that the stroke of the support (4) at its other end is defined by a sleeve (6) screwed into the hole (5) of the bearing body (1) or the machine body, the protrusion (8) of the second end of the support (4) terminating a stop (9) to define the stroke of the resilient element which rests on the support (4) and the housing (6). Mechanism according to claim 1, characterized in that a pin (10) engages with a play in the recess in the segment (2) from the first end of the support (4). Mechanism according to Claim 1 or 2, characterized in that a guide is also formed for the support (4) in the housing (6). Mechanism according to one of Claims 1 to 3, characterized in that the resilient element is a spring (7). Mechanism according to one of Claims 1 to 4, characterized in that the stop (9) is screwed onto the projection (8).