By a News Reporter-Staff News Editor at Politics & Government Week -- A patent application by the inventor KULLIN, Arne Lars Jonas (Landvetter, SE), filed on December 12, 2017, was made available online on April 19, 2018, according to news reporting originating from Washington, D.C., by VerticalNews correspondents.



This patent application is assigned to Aktiebolaget SKF.



The following quote was obtained by the news editors from the background information supplied by the inventors: "Toroidal roller bearings, such as CARB.RTM. toroidal roller bearings, are typically used for their ability of allowing both axial and angular displacement with respect to the outer ring and the inner ring of the toroidal roller bearing. This is enabled by the curved construction of the inner and outer rings' raceways which are adapted to conform to the curved shape of the roller elements, as described in European patent no. EP 0175858 for example. Hence, toroidal roller bearings combine self-aligning capability with axial displacement ability.



"In order to maintain and support the roller elements in a toroidal roller bearing it is known to provide a cage to separate adjacent roller elements from each other in the tangential direction of the toroidal roller bearing, which restricts the movements of the roller elements in relation to each other and prevents roller-to-roller contact between the roller elements.



"International Publication no. WO 2012/0044222 discloses a spacer device for roller elements in a toroidal roller bearing. The spacer device comprises a first roller-contacting surface and a second roller-contacting surface, each having a concave shape adapted to conform to respective convex contacting surfaces of the toroidal roller elements and at least one axial end portion which is elastically deformable so that the assembly of the toroidal bearing may be facilitated."



In addition to the background information obtained for this patent application, VerticalNews journalists also obtained the inventor's summary information for this patent application: "An object of the invention is to provide an improved spacer device for roller elements in a toroidal roller bearing, such as CARB.RTM. toroidal roller bearing, having an inner ring and an outer ring, wherein the toroidal roller bearing allows for axial and angular displacement between the inner ring and the outer ring, which spacer device enables efficient separation of the roller elements.



"This object is achieved by a spacer device that comprises a first roller element-contacting surface and a second roller element-contacting surface on opposite sides thereof, which first and second roller-contacting surfaces are arranged to separate two adjacent roller elements in a tangential direction of the toroidal roller bearing when the spacer device is in use, i.e. when the spacer device is mounted in a toroidal roller bearing. Each of the first and second roller element-contacting surfaces has a concave shape adapted to conform to respective convex contacting surfaces of the roller elements. The spacer device comprises end members that have projections that extend outwards from first and second roller-contacting surfaces and which are arranged to extend at least partly over the ends of two adjacent roller elements when the spacer device is in use, and thereby limit the axial movement of roller elements.



"The present invention is based on the insight that the shape of the outer ring raceway of a toroidal roller bearing geometrically prevents the rollers from excessive skew, i.e. rotation of the roller elements' rotational axis around an axis perpendicular to the raceway. Due to the geometrical prevention of skew in toroidal roller bearings, spacer devices in a toroidal roller bearing do not need to be dimensioned with strength as a priority. Furthermore, by providing spacer devices for roller elements in toroidal roller bearings which are adapted to conform to the rolling surfaces of the roller elements, the number of roller elements, and consequently the load bearing capabilities, may be enhanced in the toroidal roller bearing while enabling improved and efficient assembly. In other words, the spacer device is advantageous in that it allows for assembly of an increased number of roller elements which typically leaves less available space for intermediately arranged spacer devices. Hence, in a toroidal roller bearing comprising the spacer device according to the present invention, the carrying capacity of the bearing may be increased by increasing the number of rollers. For example, substantially the same carrying capacity as a full complement toroidal roller bearing, but without roller-to-roller contact, may be provided.



"During operation in a toroidal roller bearing, the spacer device supports and separates the roller elements and thereby avoids roller-to-roller wear between adjacent roller elements and the contact between the spacer device and the roller elements allows for a build-up of a lubricating oil film. The oil film build-up is generated by the effective non-zero velocity in the interface between a roller element-contacting surface of the spacer device and the associated rolling surface of a roller element. In other words, the effective velocity on an oil fragment between a spacer device and a roller element will not be opposite and equal, as in the case with roller-to-roller contact. Hence, the spacer device facilitates for an increased number of roller elements in the bearing which increases, or maximizes, the load bearing properties while providing efficient and durable operation due to oil film build-up.



"According to an embodiment of the invention the spacer device may comprise any suitable material. It does not necessarily have to comprise elastically deformable material but can instead comprise non-elastically deformable material.



"According to an embodiment of the invention the spacer device comprises at least one recess. Such a recess reduces the material and weight of the spacer device and may provide a channel to guide or maintain lubricating oil to where it is needed.



"According to an embodiment of the invention the spacer device comprises an opening that extends from the first roller element contacting-surface to the second roller element-contacting surface, in a tangential direction of the toroidal roller bearing when the spacer device is in use, and the opening is located at the centre of the spacer device where the tangential distance between the first and second roller element-contacting surfaces is smallest. In this way the thinnest and most fragile section of a spacer device in the tangential direction may advantageously be avoided, thereby improving the durability and stability of the spacer device. The opening allows roller elements to be arranged with minimized tangential distance between each other, wherein portions of the contacting surface of a roller element will extend into the opening during operation. Substantially zero tangential distance between the contacting surfaces at the tangentially widest sections of the roller elements may thus be provided. The tangential distance may at least be substantially reduced. Alternatively, depressions may be provided in one or both the roller element-contacting surfaces of the spacer device.



"The present invention also concerns a toroidal roller bearing that comprises at least one spacer device according to any of the preceding claims. The toroidal roller bearing may be a sealed toroidal roller bearing. The toroidal roller bearing may be used in automotive, wind, marine, metal producing applications and any other machine applications. For example, the toroidal roller bearing may be used in paper machines, continuous casters, fans and blowers, crushers and grinding mills, industrial transmissions, conveyors, and hydraulic motors and pumps.



"The present invention further concerns a method for inserting at least a final roller element or a final spacer device into a toroidal roller bearing having an inner ring, an outer ring, roller elements and a plurality of spacer devices according to any of the embodiments of the present invention inserted between adjacent roller elements, wherein the toroidal roller bearing allows for axial and angular displacement between the inner ring and the outer ring. The spacer device namely comprises a first and second roller element-contacting surface on opposite sides thereof, which first and second roller-contacting surfaces are arranged to separate two adjacent roller elements in a tangential direction of the toroidal roller bearing, and wherein each of the first and second roller element-contacting surfaces has a concave shape adapted to conform to respective convex contacting surfaces of the roller elements. The spacer device also comprises end members that have projections that extend outwards from first and second roller-contacting surfaces and which are arranged to extend at least partly over the ends of two adjacent roller elements when the spacer device is in use. The method comprises the steps of tilting the inner ring of the toroidal roller bearing with respect to the outer ring whereby the distance between rolling elements is increased, and inserting a roller element between two spacer devices, or inserting a spacer device between two roller elements.



"Such a method facilitates assembly of a toroidal roller bearing so that a spacer device according to the present invention may be inserted into the restricted available space between two closely arranged roller elements. Such a method is also advantageous in that it alleviates assembly and production considerations relating to damages occurring during manufacturing. Spacer devices can namely be mounted in a toroidal roller bearing without damaging the bearing's rings and roller elements."