Bearing assembly

Abstract

A bearing assembly (100) for supporting a dynamic load between two surfaces is provided. The bearing assembly (100) includes an inner ring (102) and outer ring (104) configured to rotate around a central axis (106) at respective rotational speeds. A speed ratio is defined between the rotational speed of the inner ring (102) and the outer ring (104). The inner ring (102) and the outer ring (104) each engage one of the two surfaces. A plurality of mechanical transmission layers (108) are concentrically disposed between the inner ring (102) and the outer ring (104). A mechanical speed control mechanism (112) is associated with two or more of the mechanical transmission layers (108). Each mechanical transmission layer (108) engages at least one other layer of the plurality of mechanical transmission layers (108) via the mechanical speed control mechanism (112) to control the speed ratio of the inner (102) and outer rings (104).

Description

[0001] BEARING ASSEMBLY

[0002] CROSS-REFERENCE(S) TO RELATED APPLICATIONS

[0003] This application claims priority from South African provisional patent application number 2024 / 06399 filed on 19 January 2025, which is incorporated by reference herein.

[0004] FIELD

[0005] This disclosure relates to the field of mechanical bearings.

[0006] BACKGROUND

[0007] Bearings are widely used in mechanical systems to support relative movement between machine components. Bearings provide support while reducing friction and energy losses, in addition to transmitting radial loads and rotational motion. Conventional bearing technologies include ball bearings, roller bearings and plain bearings, for example, which are employed in a wide variety of industrial, mechanical, and energy applications.

[0008] Despite continued development in the field, bearings remain a significant source of mechanical losses, wear, and operational limitations. Resistance within bearings contributes to excessive heat generation, wear and stress on the bearing, particularly under elevated speeds. Many traditional bearing designs are constrained by speed limitations due to a combination of material types and thermal and / or mechanical stresses at higher speeds. Continuous operation at elevated speeds may also result in quicker wear due to increased stress and strain experienced by the bearing components.

[0009] Accordingly, there remains a need for improved bearing technologies that enable higher performance under elevated speeds.

[0010] The preceding discussion of the background is intended only to facilitate an understanding of the present disclosure. It should be appreciated that the discussion is not an acknowledgment or admission that any of the material referred to was part of the common general knowledge in the art as at the priority date of the application.

[0011] SUMMARYIn accordance with an aspect of the disclosure there is provided a bearing assembly for supporting a dynamic load between two surfaces.

[0012] The bearing assembly may include an inner ring and an outer ring. The inner ring and outer ring may be configured to rotate around a central axis at respective rotational speeds, defining a speed ratio between them. The bearing assembly may include a plurality of mechanical transmission layers concentrically disposed between the inner and outer rings. The bearing assembly may include a mechanical speed control mechanism associated with two or more of the mechanical transmission layers. Each layer of the plurality of mechanical transmission layers may be configured to engage at least one other of the plurality of mechanical transmission layers via the mechanical speed control mechanism to control the speed ratio of the inner and outer rings. The inner and outer rings may each be configured to engage one of the two surfaces.

[0013] The mechanical speed control mechanism may include a gear arrangement.

[0014] The gear arrangement may include at least one gear wheel and at least one ring gear configured to mesh with the at least one gear wheel.

[0015] The gear arrangement may include at least one gear wheel and at least one ring gear associated with each of the mechanical transmission layers associated with the mechanical speed control mechanism.

[0016] The at least one ring gear associated with one mechanical transmission layer may be configured to mesh with a gear wheel associated with another mechanical transmission layer.

[0017] The mechanical speed control mechanism may include a sprocket arrangement associated with one or more of the mechanical transmission layers associated with the mechanical speed control mechanism.

[0018] The sprocket arrangement may include one or more sprocket roller tracks and one or more sprocket wheels. The one or more sprocket wheels may be configured to cooperate with the one or more sprocket roller tracks.

[0019] The sprocket arrangement may include two sprocket roller tracks and two sprocket wheels. The sprocket wheels may each be configured to cooperate with one of the two sprocket roller tracks.The mechanical speed control mechanism may include a contra-rotating mechanism.

[0020] The contra-rotating mechanism may include a split gear arrangement comprising at least two gear wheels. The two gear wheels may be configured to externally engage each other.

[0021] One or more of the mechanical transmission layers may include a load-bearing portion. Each load-bearing portion may be configured to support the dynamic load between the two surfaces in a direction radial to the central axis.

[0022] One or more of the load bearing portions may include a rolling ring.

[0023] One or more of the load bearing portions may include one or more rolling members. Each of the rolling rings may be configured to guide the one or more rolling members.

[0024] The one or more rolling members may be one or more ball elements. The rolling ring may be a race ring. The race ring may be configured to contain the one or more ball elements.

[0025] One or more of the load bearing portions may include a ball cage. The ball cage may be configured to contain the one or more ball elements within the race ring.

[0026] The one or more rolling elements may be one or more needle rollers.

[0027] The one or more rolling elements may be one or more cylindrical rollers.

[0028] The bearing assembly may include a support guide associated with one or more of the mechanical transmission layers.

[0029] One or more of the mechanical transmission layers may include one or more allowance slots. The one or more allowance slots may be configured to accommodate wear of the mechanical transmission layer.

[0030] Embodiments of the technology will now be described, by way of example only, with reference to the accompanying drawings.

[0031] BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In the drawings:Figure 1 is sectioned side view of a bearing assembly;

[0033] Figure 2 is an enlarged sectioned side view of the bearing assembly of Figure 1 ;

[0034] Figure 3 is a three-dimensional view of the bearing assembly of Figure 1 ;

[0035] Figure 4 is a schematic side view of a gear assembly;

[0036] Figure 5 is a schematic front view of the gear assembly of Figure 4;

[0037] Figure 6 is a schematic side view of a plurality of load-bearing portions;

[0038] Figure 7 is a schematic front view of the plurality of load-bearing portions of Figure 6;

[0039] Figure 8 is a schematic sectioned side view of a second bearing assembly;

[0040] Figure 9 is a schematic sectioned top view of the bearing assembly of Figure 8;

[0041] Figure 10 is an enlarged schematic sectioned side view of the bearing assembly of Figure 8;

[0042] Figure 11 is a further enlarged view of the schematic of Figure 10;

[0043] Figure 12 is a sectioned side view of a third bearing assembly; and

[0044] Figure 13 is a schematic side view of a contra-rotating mechanism.

[0045] DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS

[0046] A bearing assembly for supporting a dynamic load between two surfaces is provided.

[0047] In the example bearing assembly (100) illustrated in Figures 1 to 7, an inner ring (102) and an outer ring (104) are provided. The inner ring (102) has a diameter smaller than that of the outer ring (104), thereby allowing the inner ring (102) to fit concentrically within the outer ring (104). In use, the inner ring (102) and outer ring (104) rotate around a central axis (106) at respectiverotational speeds. A speed ratio is defined between the rotational speed of the inner ring (102) and the outer ring (104). In use, the inner ring (102) and the outer ring (104) each engage one of the two surfaces. One of the surfaces may be a shaft surface of a machine. One of the surfaces may be a bore surface of a machine housing. One or both of the inner ring (102) and the outer ring (104) may be secured to the surfaces by a friction fit, interference fit, or a clamping arrangement. Alternatively, or additionally, the inner ring (102) or the outer ring (104) may be secured to the surface by fastening, or bonding. In some embodiments, the inner ring may be axially located on a shaft surface by a shaft shoulder. The outer ring may be axially supported by a shoulder formed in a machine housing.

[0048] A plurality of mechanical transmission layers (108) are concentrically disposed between the inner ring (102) and the outer ring (104). The mechanical transmission layers (108) each have a different diameter, thereby allowing concentric fitting between the inner ring (102) and the outer ring (104). In use, the mechanical transmission layers (108) rotate around the central axis (106). Relative rotational motion between the inner ring (102) and the outer ring (104) is thereby enabled by the mechanical transmission layers (108).

[0049] The bearing assembly (100) includes a mechanical speed control mechanism (112) associated with two or more of the mechanical transmission layers (108). The mechanical speed control mechanism (112) may be mechanically coupled to two or more of the mechanical transmission layers (108). Each mechanical transmission layer (108) engages at least one other layer of the plurality of mechanical transmission layers (108) via the mechanical speed control mechanism (112) to control the speed ratio of the inner (102) and outer rings (104).

[0050] In the present example, the mechanical speed control mechanism (112) may include a gear arrangement (114), as illustrated in Figures 4 and 5. The gear arrangement (114) includes at least one gear wheel (116) and at least one ring gear (118). The at least one ring gear (118) meshes with the at least one gear wheel (116). At least one gear wheel (116) and at least one ring gear (118) is associated with each of the mechanical transmission layers (108). The at least one gear wheel (116) and at least one ring gear (118) may be axially aligned with an associated mechanical transition layer (108). The at least one ring gear (118) associated with one mechanical transmission layer (108) may mesh with a gearwheel (116) associated with another mechanical transmission layer (108).

[0051] The gear wheel (116) and the ring gear (118) may each include a set of gear teeth or a gear track that interlock during meshing, thereby transmitting rotary motion. The ring gear (118) may be slotted to allow fitting of one or more gear wheels (116). A plurality of ring gears (118) maybe located concentrically. Each ring gear (118) of the plurality of concentric ring gears has a different diameter thereby allowing concentric fitting.

[0052] Gear wheels 1 to 7 and ring gears A to G are illustrated in Figure 5. In use, the inner ring (102) rotates at a speed corresponding to the rotational speed of the surface it engages. The inner ring (102) engages gear wheel 1, thereby transmitting rotational motion to gear wheel 1. Gear wheel 1 meshes with and transmits rotational motion to ring gear B. Additionally, gear wheel 1 rotates around a pivot slot hinge (120) of ring gear A, thereby hauling ring gear A. Ring gear A, being hauled by gearwheel 1, transmits rotation against ring gear B, through turning gearwheel 2. Gearwheel 2 in turn hauls ring gear B. The sequence of transmission is thus: inner ring (102) to gear wheel 1 to ring gear B hauling ring gear A, ring gear A to gear wheel 2 to ring gear C hauling ring gear B, and so on.

[0053] Transmission of rotary motion from the inner ring (102) to gearwheel 7 is summarised below:

[0054] ■ Inner ring (102) to gearwheel 1 to ring gear B hauling ring gear A

[0055] ■ Ring gear A to gear wheel 2 to ring gear C hauling ring gear B

[0056] ■ Ring gear B to gear wheel 3 to ring gear D hauling ring gear C

[0057] ■ Ring gear C to gear wheel 4 to ring gear E hauling ring gear D

[0058] ■ Ring gear D to gear wheel 5 to ring gear F hauling ring gear E

[0059] ■ Ring gear E to gear wheel 6 to ring gear G hauling ring gear F

[0060] ■ Ring gear F to gear wheel 7 to ring gear H hauling ring gear G

[0061] Each mechanical transmission layer (108) includes a load-bearing portion (122) that supports the dynamic load between the two surfaces in a direction radial to the central axis (106). Each of the load bearing portions (122) includes a rolling ring (124). Each of the load bearing portions (122) includes one or more rolling members (126). In use, each of the rolling rings (124) may guide the one or more rolling members (126). The load-bearing portions (122) support the dynamic load between the two surfaces. This ensures that the speed control mechanism (112) is not subjected to bearing loads.

[0062] A rolling ring (124) may include a track or race for guiding the one or more rolling members (126). In the present example, the one or more rolling members (126) are one or more ball elements. The rolling ring (124) may include one or more of a race ring and a ball cage. The race ring may contain the one or more ball elements. The ball cage may tangentially separate the ball elements within the rolling ring. The race ring may contain the one or more ball elements in a manner similar to a traditional ball bearing assembly.A different number of rolling elements may be present within the load-bearing portions (122) of different mechanical transmission layers (108). In the present example, the load bearing portion (122) of a mechanical transmission layer (108a) includes one ball element, as illustrated in Figure 7. The load-bearing portion (122) of a mechanical transmission layer (108b) includes two ball elements, and the load-bearing portion (122) of a mechanical transmission layer (108c) includes three ball elements.

[0063] The bearing assembly (100) may include one or more support guides (130) each associated with one of the mechanical transmission layers (108). The one or more support guides (130) may be referred to as axial support guides. The axial support guides (130) may be fitted to each side of the bearing assembly (100). The axial support guides (130) may be mechanically coupled inwardly through one or more mechanical transmission layers (108) up to the mechanical speed control mechanism (112).

[0064] A further example bearing assembly (200) is illustrated in Figures 8 to 11. The bearing assembly (200) includes an inner ring (202) and an outer ring (204). In use, the inner ring (202) and outer ring (204) rotate around a central axis at respective rotational speeds, defining a speed ratio between them. In use, the inner ring (202) and the outer ring (204) each engage one of the two surfaces. A plurality of mechanical transmission layers (208) are concentrically disposed between the inner ring (202) and the outer ring (204).

[0065] The bearing assembly (200) includes a mechanical speed control mechanism (212) associated with two or more of the mechanical transmission layers (208). Each mechanical transmission layer (208) engages at least one other layer of the plurality of mechanical transmission layers (208) via the mechanical speed control mechanism (212) to control the speed ratio of the inner (202) and outer rings (204).

[0066] The mechanical speed control mechanism (212) includes a sprocket arrangement (214) associated with each of the mechanical transmission layers (208) that are associated with the mechanical speed control mechanism (212). The sprocket arrangement (214) includes one or more sprocket roller tracks (216) and one or more sprocket wheels (218) configured to cooperate with the one or more sprocket roller tracks (216). In the present embodiment, each sprocket arrangement (214) includes two sprocket roller tracks (216) and two sprocket wheels (218). The combination of two sprocket roller tracks (216) and two sprocket wheels (218) may be referred to as a double sprocket arrangement. Each sprocket wheel cooperates with one of the two sprocket roller tracks (216) in the double sprocket arrangement.The double sprocket arrangement is suited for bearing applications where space limitation presents a challenge, such as in slim-line applications. The double sprocket arrangement avails a high speed-reduction ratio that requires minimal changes to the sprockets only. The improved speed ratio control in fine spaces offered by the double sprocket arrangement is accompanied by a slightly higher machining cost compared to the gear assembly.

[0067] Each mechanical transmission layer (208) includes a load-bearing portion (222) that supports the dynamic load between the two surfaces in a direction radial to the central axis. Each of the load bearing portions (222) includes a rolling ring (224). Each of the load bearing portions (222) includes one or more rolling members (226). In use, each of the rolling rings (224) may guide the one or more rolling members (226). One or more of the rolling rings (224) may be mechanically coupled to one or more of the sprocket roller tracks (216). In the present embodiment, the one or more rolling elements is a needle roller. The load bearing portion (222) includes a roller cage (228) for supporting the needle roller.

[0068] An exemplary calculation for the double sprocket arrangement is provided.

[0069] Referring to Figure 11, rolling ring W rotates at a speed of 1700rps and feeds to rolling ring Y. Sprocket wheel 1 is geared to a sprocket roller track mechanically coupled to rolling ring W, transmitting a speed of 1700rps through sprocket wheel 1 hauling rolling ring Y and driving rolling ring Z through sprocket wheel 2. The speed calculation of rolling ring Y given this arrangement is as follows:

[0070] Rolling Ring Y Speed = Applied speed of Rolling Ring W multiplied by (Rolling Ring W diameter divided by Rolling Ring Y diameter)

[0071] = 1700rps X (235.294mm / 237.294mm)

[0072] = 1685rps

[0073] It is clear that the speed reduction at this point offers a lesser speed differential than required as in the case of all preceding roll ring sets at 100rps. In order to make up for the differential shortfall on hand to 1600rps we therefore effect a factor application to determine the required size for the secondary sprocket. That will be done in relation to the primary sprocket diameter as in Rolling Ring Y required speed divided by the preceding calculated speed and multiplied by the primary sprocket diameter. A factor of the set will be used to determine the diameter of the sprocket wheel 2 as in the following:Sprocket wheel 2 factor = Rolling Ring Y required speed / Rolling Ring Y calculated speed = 1600rps 11685rps

[0074] = 0.949176

[0075] We now have a factor for adjusting the speed of sprocket wheel 2 by dividing the 2mm diameter of sprocket wheel 1 by the factor. The required diameter to effect to the secondary sprocket 1 is 2mm I 0.949176 = 2.10709mm. Therefore, the speed of rolling ring Y with the determined diameter will be 1600rps.

[0076] A further example bearing assembly (300) is illustrated in Figures 12 and 13. The bearing assembly (300) includes an inner ring (302) and an outer ring (304). In use, the inner ring (302) and outer ring (304) rotate around a central axis (306) at respective rotational speeds, defining a speed ratio between them. In use, the inner ring (302) and the outer ring (304) each engage one of the two surfaces. A plurality of mechanical transmission layers are concentrically disposed between the inner ring (302) and the outer ring (304).

[0077] The bearing assembly (300) includes a mechanical speed control mechanism associated with two or more of the mechanical transmission layers. Each mechanical transmission layer engages at least one other layer of the plurality of mechanical transmission layers (308) via the mechanical speed control mechanism to control the speed ratio of the inner (302) and outer rings (304).

[0078] In the present example, the mechanical speed control mechanism includes a contra-rotating mechanism (314). In use, the contra-rotating mechanism (314) transmits rotary motion of the inner ring (302) to the outer ring (304) via a contra-rotating gear arrangement. The contrarotating mechanism includes a split gear arrangement comprising at least two gear wheels (318). The gear wheels (318) externally engage each other in use. The conversion mechanism may include an outer gear (317) mechanically coupled to the outer ring (304). The contrarotating mechanism may include a drive gear (319). One or more of the gear wheels (318) may engage the drive gear (319) in use and one or more of the gear wheels may engage a gear coupled to the outer ring (304) in use, thereby transmitting rotation from the inner ring (302) to the outer ring (304).

[0079] The contra-rotating mechanism (314) of the present embodiment comprises three gear wheels, including two lower gear wheels (318a) and one upper gear wheel (318b). The two lower gear wheels (318a) each externally engage the upper gear wheel (318b). The upper gear wheel (318b) externally engages the drive gear (319) by meshing.The contra-rotating mechanism (312) may include a tension arrangement, comprising a recoil bar (320) and two swing struts (322). The swing struts (322) connect the gear wheels (318) at their respective axes to the recoil bar (320). Position drop of the contra-rotating mechanism (312) due to wear over time is expected. The tension arrangement ensures full gear engagement contact between the gear wheels (318) and the outer ring (304) during such anticipated position drop. The drive gear (319) has a dimension selected to allow wear amounting to at most 25 mm.

[0080] In use, the gear mechanically coupled to the inner ring (302) engages and transmits rotation to the drive gear (319) via internal gear engagement, thereby causing the drive gear (319) to rotate in the same direction as the inner ring (302). The drive gear (319) internally engages and transmits rotation to the outer gear (317), causing the outer gear (317) to also rotate in the same direction. Similarly, the outer gear (317) engages and transmits rotation to the split gear arrangement, causing the lower two gearwheels (318a) of the contra-rotating mechanism (314) to rotate in the same direction as that of the outer gear (317). The lower two gear wheels (318a) externally engage the upper gear wheel (318b). The upper gear wheel (318b) therefore rotates in a direction opposite to that of the lower two gear wheels (318a). The upper gear wheel (318b) externally engages with the gear mechanically coupled to the inner ring (302), affirming the rotary motion in opposite directions, in accordance with external gear meshing principles.

[0081] In comparison to the gear assembly (114) and double sprocket arrangement (214), the contrarotating mechanism (314) offers a larger speed reduction ratio, lower part count and increased contact area. Increased contact area is enabled by the use of the tension arrangement.

[0082] In use, the bearing assembly aims to reduce the impact of the supported dynamic load, including high speed loads and centrifugal forces. The internal speeds of the bearing assembly may be reduced to desired levels by customisation of components of the bearing assembly, such as the size and number of the mechanical transmission layers. This customisation allows a user to set desired properties of the bearing assembly, such as fatigue life, rate of wear, energy economy, and thermal capacity. The present invention therefore provides for increased operating life, increased radial and axial load bearing factors, decreased maintenance, longer precision and stiffness retention, and greater suppression of centrifugal forces compared to a traditional bearing of similar size. Increased performance of the bearing assembly relative to a traditional bearing thereby enables lower cost, as the cost-to-performance ratio decreases.

[0083] Further examples may provide a bearing assembly including one or more of the mechanicalspeed control mechanisms of the types described herein. For example, the bearing assembly may include a gear arrangement and a sprocket arrangement within the speed control mechanism. Additionally, further examples may include any of the described load-bearing portion types described herein, or any other load-bearing elements known in the mechanical bearing arts.

[0084] It should be appreciated that a bearing assembly having a speed control mechanism incorporating the gear assembly, double sprocket arrangement, and contra-rotating mechanism may enable optimal performance and customisation tailored to a specific application. The optimal performance enabled by integration of all three speed control mechanism types leads to a decrease in costs compared to traditional bearings.

[0085] The foregoing description has been presented for the purpose of illustration; it is not intended to be exhaustive or to limit the technology to the precise forms disclosed. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above disclosure.

[0086] The language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the present disclosure be limited not by this detailed description, but rather by any claims that issue on an application based hereon. Accordingly, the present disclosure is intended to be illustrative, but not limiting, of the scope of any accompanying claims.

[0087] Finally, throughout the specification and any accompanying claims, unless the context requires otherwise, the word ‘comprise’ or variations such as ‘comprises’ or ‘comprising’ will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims

CLAIMS:

1. A bearing assembly for supporting a dynamic load between two surfaces, comprising:an inner ring and an outer ring configured to rotate around a central axis at respective rotational speeds, defining a speed ratio between them;a plurality of mechanical transmission layers concentrically disposed between the inner and outer rings; anda mechanical speed control mechanism associated with one or more of the mechanical transmission layers,wherein each layer of the plurality of mechanical transmission layers is configured to engage at least one other of the plurality of mechanical transmission layers via the mechanical speed control mechanism to control the speed ratio of the inner and outer rings, andwherein the inner and outer rings are each configured to engage one of the two surfaces.

2. The bearing assembly of claim 1, wherein the mechanical speed control mechanism includes a gear arrangement.

3. The bearing assembly of claim 2, wherein the gear arrangement includes at least one gear wheel and at least one ring gear configured to mesh with the at least one gear wheel.

4. The bearing assembly of claim 3, wherein the gear arrangement includes at least one gear wheel and at least one ring gear associated with each of the mechanical transmission layers associated with the mechanical speed control mechanism.

5. The bearing assembly of claim 4, wherein the at least one ring gear associated with one mechanical transmission layer is configured to mesh with a gear wheel associated with another mechanical transmission layer.

6. The bearing assembly of any one of the preceding claims, wherein the mechanical speed control mechanism includes a sprocket arrangement associated with each of the mechanical transmission layers associated with the mechanical speed control mechanism.

7. The bearing assembly of claim 6, wherein the sprocket arrangement includes one or more sprocket roller tracks and one or more sprocket wheels configured to cooperate with the one or more sprocket roller tracks.

8. The bearing assembly of claim 7, wherein the sprocket arrangement includes two sprocket roller tracks and two sprocket wheels each configured to cooperate with one of the two sprocket roller tracks.

9. The bearing assembly of any one of the preceding claims, wherein the mechanical speed control mechanism includes a contra-rotating mechanism.

10. The bearing assembly of claim 9, wherein the contra-rotating mechanism includes a split gear arrangement comprising at least two gear wheels configured to externally engage each other.

11. The bearing assembly of any one of the preceding claims, wherein one or more of the mechanical transmission layers includes a load-bearing portion configured to support the dynamic load between the two surfaces in a direction radial to the central axis.

12. The bearing assembly of claim 11, wherein one or more of the load bearing portions includes a rolling ring.

13. The bearing assembly of claim 12, wherein one or more of the load bearing portions includes one or more rolling members, and wherein each of the rolling rings are configured to guide the one or more rolling members.

14. The bearing assembly of claim 13, wherein the one or more rolling elements is a needle roller.

15. The bearing assembly of claim 13, wherein the one or more rolling members is one or more ball elements and the rolling ring is a race ring configured to contain the one or more ball elements.

16. The bearing assembly of claim 15, wherein one or more of the load bearing portions includes a ball cage configured to contain the one or more ball elements within the race ring.

17. The bearing assembly of any one of the preceding claims, including one or more support guides each associated with one of the mechanical transmission layers.

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