JPH07224843A - High follow-up type pad support washer - Google Patents

Abstract

PURPOSE:To improve reliability of a thrust bearing by a method wherein crowning or relief processing is applied in an radial direction on an end part, except the contact part, of the central part of a portion where the upper and lower lockers of a pad support washer make contact with each other and a ratio between right and left locker levers based on a central pivot is reduced. CONSTITUTION:A pad support washer 1 consists of a plurality of sets of upper and lower pad support washers. In the locker part A of the pad support washer 1, crowning or relief processing is applied in a radial direction, as shown by an oblique line, on a portion where upper and lower lockers makes contact with each other and on the end, except a central part L, of the portion. As a result, the upper and lower lockers make contact with a line passing through a pivot center B and intercoupling points C and D and compared with a case of crowning or relief processing being not applied, a ratio E:F between left and right locker levers based on a pivot center B is reduced to a lower value. This constitution increases rigidity of a contact line, easily keeps a moment balance, and hardly produces the change of a contact position between the pad support washers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the shape of a pad washer for a Kingsbury type thrust bearing.

[0002]

2. Description of the Related Art FIG. 2 is a plan sectional view of a pad washer portion of a Kingsbury type thrust bearing.

In the figure, six or eight pads 12 are incorporated in sliding contact with the thrust collar 11, and a pivot 13 is attached to the back surface of the pad 12.

An upper pad washer 14 is disposed in contact with a semi-elliptical spherical projection of the pivot 13.

The back surface of the upper pad bearing seat 14 and the back surface of the lower pad bearing washer 15 are assembled with the rocker portions A in contact with each other. A semi-elliptical spherical projection is formed on the front surface of the lower pad washer 15 and is in contact with the base ring 16.

In the thrust bearing having such a structure,
When the thrust collar and the pad are misaligned during assembly of the thrust case or during operation, both pad washers 14 and 15 on the back surface of the pad 12 contact the rocker portion A with each other over the entire circumference. Follow to share the load.

[0007]

By the way, in a thrust bearing having a ratio of outer diameter to inner diameter of about 2, if the number of pads is increased to increase the load capacity, the misalignment of the pad washer causes the inclination of the pad washer. There is a tendency for the pad load to increase and the load distribution to be non-uniform, that is, to be sensitive to changes in the load sharing ratio.

This is because the contact position between the pad washers easily changes due to misalignment, and as shown in FIG. 3, a contact connecting both contact points C'and D'through the center B of the pivot. It is considered that the lever ratio E'to F'of the line is relatively large and the contact surface pressure of the rocker portion A of the pad washer is low.

The curve shown by the two-point diagonal lines in FIG. 3 shows the distribution of the contact force.

An object of the present invention is to eliminate the above problems.

[0011]

As a structure for achieving the above object, the high-following type pad washer of the present invention is applied to a thrust collar in a Kingsbury type thrust bearing used in a steam turbine, a gas turbine or the like. The ends of the plurality of pairs of pad washers arranged between the sliding contact pad and the base ring are left in contact with each other, and the upper rocker (pad side) and the lower rocker (base ring side) contact each other. Part in the radial direction, crowning or
It features relief processing, and the ratio of left and right rocker levers to the central pivot is small.

[0012]

The high-following type pad washer of the present invention constructed as described above has the end portions thereof crowned or relief-processed in the radial direction, leaving a contacting portion at the center of the contacting portions of the pad washer. As a result, the rocker lever ratio is reduced, the rigidity of the contact line is increased, the moment balance is facilitated, and the contact position between the pad washers is less likely to change.

Therefore, the pad load becomes relatively uniform even when a large misalignment is absorbed, so that variations in bearing metal temperature are reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1A and 1B are processing views of a high-following type pad washer of the present invention, FIG. 1A is a front view, and FIG. 1B is a view taken along line XX of FIG.

In the figure, the pad washer 1 comprises a plurality of sets of upper pad washer and lower pad washer as described above with reference to FIG.
Is a portion where the upper and lower rockers are in contact with each other, and is configured such that crowning or relief processing is performed in the radial direction, as shown by the shaded portion of the end portion, leaving the central portion L of this portion.

As a result, the upper rocker and the lower rocker come into contact with the line passing through the center B of the pivot and connecting the points C and D, so that the rocker lever ratio E on the left and right with respect to the center B of the pivot is E, as compared with the case without crowning or relief processing.
Pair F is getting smaller.

As a result, the rigidity of the contact line is increased, the moment balance is easily balanced, and the change in the contact position between the pad washers is less likely to occur.

Therefore, the pad load becomes relatively uniform even when a large misalignment is absorbed, so that the variation in the metal temperature of the bearing is also reduced.

The other structure is the same as that described as the conventional device in FIG.

[0020]

As described above, according to the high-following pad washer of the present invention, even if the number of pads is increased to increase the load capacity, the contact position between the pad washer hardly changes.

Therefore, even when a large misalignment is absorbed, the pad load becomes relatively uniform, and as a result, variations in the metal temperature of the bearing are reduced and the reliability of the thrust bearing is improved.

[Brief description of drawings]

1A and 1B are processing views of a high-following type pad washer according to an embodiment of the present invention, in which FIG. 1A is a front view and FIG.
It is a -X arrow view.

FIG. 2 is a plan sectional view of a pad washer of a thrust bearing.

FIG. 3 is a contact state diagram of a conventional pad washer.

[Explanation of symbols]

 1 Pad washer A Rocker part B Pivot center E, F Rocker lever ratio

Claims (1)

[Claims] 1. In a Kingsbury type thrust bearing used for a steam turbine, a gas turbine, etc., an upper rocker (pad side) of a plurality of sets of pad washers arranged between a pad slidably contacting a thrust collar and a base ring. ) And the lower rocker (base ring side) contact each other, leaving the central contact part in the radial direction, and crowning or relief processing the end part in the radial direction to reduce the left and right rocker lever ratio to the central pivot. A high-following type pad washer characterized by