GB2563706A

GB2563706A - Spherical bearing

Info

Publication number: GB2563706A
Application number: GB1803214.4A
Authority: GB
Inventors: Lars Johansson Thomas
Original assignee: Ltj As
Current assignee: Ltj As
Priority date: 2017-03-01
Filing date: 2018-02-27
Publication date: 2018-12-26
Also published as: NO342609B1; SE1830065A1; NO20170304A1; GB201803214D0

Abstract

A spherical bearing has an inner spherical bearing member 306, an outer spherical bearing member 301, and two intermediate spherical bearing members 302-305 radially stacked in between the said inner and outer spherical bearing members, with each intermediate spherical bearing member being relatively rotatable to every other spherical bearing member. The bearing can have balls (fig 1-2), rollers (fig 4) or plain sliding surfaces. Each pair of bearing members can have a substantially common frictional moment so that the circumferential speeds of each pair is substantially the same. The frictional moment increases from the inner to the outer pairs so that the circumferential speed decreases from the inner to the outer. The bearings may have cages or seals.

Description

SPHERICAL BEARING

Technical field

The present invention relates to the field of spherical bearings and can be used where inner ring needs to misalign with respect to the outer ring. The bearing is especially suitable for high rotational speeds, large misalignment angle and low friction applications.

Background

The present invention relates to spherical bearings, especially spherical bearings applied between a fixed body and misaligned shaft. In a spherical bearing between a fixed body and a rotating shaft it is difficult to combine low friction, high rotational speed, high load and large misalignment angle between inner and outer ring. High friction leads to high temperatures, and high temperatures might damage the lubricant and this yield shorted service life for the spherical bearing.

Known spherical bearing have a relatively short lifetime due to friction and wear. It is desirable with extended service life and a more energy efficient solution.

Patent US1494695 (A) and US2475493 (A) utilizes a low friction roller- and ball bearing with parallel rows of rotating elements. Patent US 2012051679 A utilizes an aircraft spherical bearing assembly comprises a first part which is in sliding contact with an intermediate part for sliding therebetween to form a spherical joint.

Patent GB 2284237 A utilizes A spherical bearing comprises an outer housing having an inner concave surface, an inner sleeve, and an intermediate ball composed of a substantially soft compressible composite material.

Patent GB 230974 A utilizes Self - aligning bearings, such as that between a crank pin and tihe sleeve valve A of an internal combustion engine. GB 330900 A describes self-aligning spherical joints or bearings. Patent WO 2016188526 A relates to a method for producing a spherical bearing, comprising an inner ring, which has a convexly curved spherical sliding surface, and an outer ring, which surrounds the inner ring.

The design of today's spherical bearings makes it difficult to preform condition monitoring.

An object of the present invention is to deal with the previously mentioned disadvantages. A further object with the present invention is to provide a spherical bearing suitable for high rotational speed.

It is a particular object of the present invention to provide a spherical bearing that reduces friction. A second particular object with the present invention is to provide a spherical bearing where the different bearings rows can be condition monitored when the spherical bearing is both in and out of service.

Short summary of the invention

This invention reduces friction, wear and tear through a spherical bearing comprising inner and outer circular bearing rings wherein the bearing rings are rotatable with respect to each other. This yields a reduced relative motion at the bearing interface. This leads to an extended service life, a reduction in friction and enables higher rotational speeds.

An object of the present invention is to deal with the previously mentioned disadvantages.

It is a particular object of the present invention to provide a spherical bearing with improved friction, wear and tear properties and an extended service life.

The invention is a spherical bearing comprising: - at least one inner spherical bearing member (306), and - at least one outer spherical bearing member (301), wherein the inner spherical bearing member is arranged to be fixed to a shaft, wherein the spherical bearing comprises a first intermediate spherical bearing member (305) that is radially stacked between the inner and outer spherical bearing members (306, 301), wherein the first intermediate spherical bearing member (305) is rotatable relative the inner and outer spherical bearing members.

Figure captions

An illustrative and non-limiting embodiment of the present invention will be described below in detail with reference to the appended drawings, in which:

Figures 1-4 illustrates the spherical bearing comprising inner, outer and intermediate spherical bearing rings.

Embodiments of the invention

An embodiment of the invention illustrated by figure 1 is a partial cross section view of a spherical bearing comprising inner 105, outer 101 and first intermediate 103 spherical bearing ring to be used between a fixed body and a shaft. The rolling element are balls. The first inner spherical bearing ring 102 is configured to be in contact with an inner row of rolling elements 104 and arranged to be fixed to a shaft. The first intermediate spherical bearing ring 104 is radially stacked between an inner 104 and outer 102 row of rolling elements and the first intermediate spherical bearing ring is rotatable and angular movable relative said inner and outer 101, 105 spherical bearing rings. The intermediate spherical ring 104 comprises one inward facing spherical raceway and one outward facing ball raceway. The outer spherical bearing ring 101 is in contact with outer row of rolling elements 102 and in contact with the fixed body. The inner and outer rows of rotating elements should have a substantially common frictional moment so that the circumferential speeds of the rows of rotating elements are substantially the same. If the frictional moment increases from the inner to the outer rows of rotating elements the circumferential speed decreases from the inner to the outer rotating elements.

An embodiment of the invention illustrated by figure 2 is a partial cross section view of a spherical bearing comprising inner 206, 205 outer 202, 203 and a first intermediate 204 spherical bearing ring. The invention is to be used between a fixed body and a shaft and the rolling elements are balls. The first inner spherical bearing assembly ring 207 is configured to be in contact with a double inner row of rolling elements 205 and 206.The inner spherical bearing ring is arranged to be fixed to a shaft. The intermediate spherical bearing ring 204 is radially stacked between the double inner row 205, 206 and a double outer row 202, 203 of rolling elements. The first intermediate spherical bearing ring is rotatable and angular movable relative the inner and outer 201, 207 spherical bearing rings and comprises one inward facing spherical raceway and two outward facing ball raceways. The outer spherical bearing ring 201 is in contact with double outer row of rolling elements 202, 203 and the outer spherical bearing ring 201 is in contact with the fixed body.

There are different configurations of the spherical bearing, in one configuration the inner ring rotates and the outer ring is fixed. In the other configuration, the outer ring is rotating and the inner is fixed.

The inner and outer rows of rotating elements should have a substantially common frictional moment so the circumferential speeds of the rows of rotating elements are substantially the same. If the frictional moment increases from the inner to the outer rows of rotating elements the circumferential speed decreases from the inner to the outer rotating elements.

An embodiment of the invention illustrated by figure 3 is a partial cross section view of a spherical bearing comprising inner 306, outer 301 and a multiple of intermediate 302-305 wheel bearing members to be used between a fixed body and a rotating body. The first inner spherical bearing member 306 is configured to be in contact with the first intermediate spherical bearing member 305 and arranged to be fixed to a shaft. The first intermediate spherical bearing member 305 is radially stacked between the inner spherical bearing member and a second intermediate spherical bearing member 304. The following (303-302) intermediate spherical bearing members are radially stacked between the second intermediate and outer spherical bearing members. The intermediate spherical bearing members are plain bearings and should have a substantially common frictional moment so that the circumferential speeds of the plain bearings are substantially the same. If the frictional moment increases from the first to the last of the plain bearing the circumferential speed decreases from the first to the last of the plain bearings.

An embodiment of the invention illustrated by figure 4 is a partial cross section view of a spherical bearing comprising inner 401, outer 410, first and second 404, 407 intermediate spherical bearing rings. The rolling elements are spherical rollers. The outer and inner spherical bearing rings 410, 401 are to be arranged between a fixed and a rotating body. The first inner spherical bearing assembly ring 401 is configured to be in contact with a double inner row of rolling elements 402 and 403. The inner spherical bearing ring is arranged to be fixed to a shaft. The intermediate first and second spherical bearing ring 404 and 407 is radially stacked between a double inner row 402, 403 and a double outer row 408, 409 of rolling elements. The first and second intermediate spherical bearing rings are rotatable and angular movable relative the inner and outer 401, 410 spherical bearing rings and each other. The first and second intermediate spherical rings comprises inward facing spherical raceway and two outward facing roller raceways. The outer spherical bearing ring 410 is in contact with double outer row of rolling elements 408, 409 and the spherical bearing ring in contact with the fixed body.

All rows of rotating elements should have a substantially common frictional moment so the circumferential speeds of each of the rotating elements rows are substantially the same. If the frictional moment increases from the inner to the outer rows of rotating elements the circumferential speed decreases from the inner to the outer rotating elements.

It should be noted that the embodiments illustrated and described were given merely by way of non-limiting indicative examples and that modifications and variations are possible within the scope of the invention as defined by the appended claims. Thus, the invention applies not only to balls and spherical roler but also other rotational elements, such as rollers. It should also be easily understood that the rotating elements are kept separated by a cage and that the spherical bearing comprises seals.

The spherical bearing described reduces friction, wear and tear by the use of a spherical bearing comprising inner and outer spherical bearing rings wherein the spherical bearing rings are rotatable with respect to each other. The spherical bearing further comprises a first intermediate spherical bearing ring that is radially stacked between the inner and outer rotating elements and rotatable relative the inner and outer spherical bearing rings. This results in a reduced relative motion between two adjacent spherical bearing rings. This leads to an extended service life, a reduction in friction and enables a higher maximal speed. The definition parallel connected spherical bearing rings means, that the spherical bearing has at least two spherical bearing rings that are rotatable relative each other.

Parallel connected spherical bearing rings:

The frictional moment (Equation 1) for n parallel connected spherical bearing rings can be expressed by M (Eq.l):

(Equation 1)

As follows from Equation 1, the frictional moment is inversely proportional to the sum of the individual frictional moment components in a device with parallel connected spherical bearing rings. Lowest frictional moment occurs when; M,=M2 = Mn.

If one of the individual rotating spherical bearing rings during use has higher friction than any of the others, it results in a lower relative speed for that individual spherical bearing ring and higher relative speeds for the other individual rotating rings. The friction loss will be substantially the same for all relatively individual rotating spherical bearing rings (Eq.2). iyM1 « I//M2 (Equation 2)

Claims

1. Aspherical bearing comprising: - at least one inner spherical bearing member (306), and - at least one outer spherical bearing member (301), wherein said inner spherical bearing member is arranged to be fixed to a shaft, characterized in that the spherical bearing comprises a first intermediate spherical bearing member (305) that is radially stacked between said inner and outer spherical bearing members (306, 301), wherein said first intermediate spherical bearing member (305) is rotatable relative said inner and outer spherical bearing members, wherein the spherical bearing comprises a second intermediate spherical bearing member (304) that is radially stacked between said inner and outer bearing members, wherein said second bearing member is rotatable relative said inner, outer and first intermediate spherical bearing members.

2. The spherical bearing according to claim 1, wherein said first and second intermediate wheel bearing members have a substantially common frictional moment so that the circumferential speeds of said spherical bearing members are substantially the same.

3. The spherical bearing according claim 1, wherein said spherical bearing comprises at least an inner row with rotating elements (104) and at least an outer row with rotating elements (102), that are radially stacked between said inner and outer (105, 101) spherical bearing members, wherein said rotating rows of rotating elements are separated from each other by said first intermediate spherical bearing member (103).

4. The spherical bearing according to any of the preceding claims, wherein the spherical bearing comprises at least one seal.

5. The spherical bearing according to any of the preceding claims, wherein at least one row of said rotating element are balls.

6. The spherical bearing according to any of the preceding claims, wherein at least one row of said rotating element are rollers.

7. The spherical bearing according to claim 1-3, wherein the circumferential speed decreases from the inner to the outer rotating elements.

8. The spherical bearing according to any of the preceding claims, wherein the first intermediate spherical ring comprises at least one inward facing spherical raceway.

9. The spherical bearing according to any of the preceding claims, wherein the first intermediate spherical ring comprises at least one outward facing ball raceway.

10. The spherical bearing according to any of the preceding claims, wherein the first intermediate spherical ring comprises at least one outward facing roller raceway.