Slewing bearing with load monitoring function

Abstract

The invention relates to a pivotal bearing (1) for rotatably supporting an object on a base about a pivot axis. The pivotal bearing comprises a fixed ring part (2) and a rotating ring part (3). The fixed ring part is provided with a fixed raceway member forming a fixed raceway surface oriented substantially perpendicular to the axis of revolution. The rotating ring part is provided with a rotating raceway member (7) forming a rotating raceway surface. Rolling elements (9) are arranged between the fixed raceway surface and the rotating raceway surface. The pivotal bearing further comprises an elastically compressible elastic insert (8) sandwiched between the rotating raceway member and the rotating ring member, or sandwiched between the fixed ring member and the fixed raceway member. The pivotal bearing further comprises an axial load sensor (10) for monitoring the axial load on the pivotal bearing by measuring the distance on the resilient insert.

Description

Technical Field

[0001] The invention relates to a slewing bearing for rotatably supporting an object on a base about a slewing axis. For example, the slewing bearing supports a crane or a crane component. The slewing bearing can also support an excavator, such as a backhoe. The base can be implemented, for example, as a barrel, a column or a base.

[0002] The present invention further relates to a crane or a backhoe dredger provided with the slewing bearing, a ship comprising the crane or the backhoe dredger, and a method for hoisting an object using a crane on a ship. Background Art

[0003] For example, WO2008088213A2 describes a lifting crane comprising a vertical column, a boom and a boom connection member, the boom being pivotably connected to the boom connection member. The crane further comprises a slewing bearing extending around the column and carrying the boom connection member rotatable around the column.

[0004] For example, in WO2019027325A1, the slewing bearing includes an elastically compressible elastic insert (which contains plastic material), which is clamped between a rotating raceway component and a rotating ring component, so that the rotating ring component is elastically supported on the roller of the slewing bearing via the rotating raceway component and the elastic insert.

[0005] The axial load component on the slewing bearing comes from the weight of the crane or crane components, and the load applied to the crane when performing a lifting operation. When performing a lifting operation, not only an axial load component is generated, but also a radial load component and a momentum load are generated. When a load is lifted using a slewing lifting crane (for example, the crane of WO2008088213A2 or WO2019027325A1), the heavy load is supported by the crane deviating from the middle of the slewing bearing, and this causes the slewing bearing to be subjected to axial, radial and momentum loads, which are unevenly distributed on the slewing bearing. During the slewing of the crane, for example when the load to be lifted is suspended from the crane, the load distribution on the slewing bearing will also move with the slewing motion.

[0006] Systems for monitoring the load acting on a slewing bearing are known. For example, EP1528356B discloses a slewing bearing and a monitoring device for monitoring the slewing bearing. The monitoring device comprises a sensor for detecting the relative movement of the bearing rings relative to each other. In particular, the tilt of the bearing rings can be monitored or determined based on the determined radial and axial movement. The sensors are non-contact displacement sensors, which can be radially aligned and scan the outer peripheral surface of the bearing rings, two sensors are arranged inside the bearing rings, and the heads of the sensors are arranged in the sealed bearing gap of the slewing bearing.

[0007] A disadvantage of known slewing bearings and the accompanying monitoring solutions is that they are susceptible to breakage or failure during use. For example, the system of EP1528356B uses a contactless displacement sensor arranged in one bearing ring to measure through the bearing gap to the other bearing ring. In practice, the bearing gap is partially filled with lubricating oil, grease and / or other products (e.g. contaminants from the outside and / or (metal) particles due to wear), which may prevent the sensor from working properly. Summary of the invention

[0008] It is an object of the present invention to provide an improved slew bearing. It is another object of the present invention to provide a slew bearing which allows for improved monitoring of the load on the slew bearing. It is another object of the present invention to provide an alternative slew bearing.

[0009] The present invention provides a slewing bearing according to claim 1 .

[0010] The slewing bearing is configured for supporting an object rotatably about a slewing axis on a base. For example, the object is a crane or a part of a crane, such as a crane boom or a jib.

[0011] For example, the foundation may be mounted on the hull of a ship so that the slew bearing may be used to support a crane on the ship for offshore operations.

[0012] The base may further be arranged on shore, such as on a vehicle or on the ground, for supporting the crane via a slewing bearing for onshore operations.

[0013] The base is preferably an annular base having similar annular dimensions as the slew bearing.

[0014] The slew bearing can have, for example, an inner diameter of more than 5 meters, for example more than 10 meters, for example more than 15 meters, for example more than 20 meters.

[0015] The slewing bearing includes:

[0016] - a fixing ring member which is connected or connectable to the base, and

[0017] - A rotating ring member which is connected or connectable to an object which is rotatable about an axis of revolution.

[0018] The fixed ring member is configured to remain fixed relative to a base to which the fixed ring member is connected or connectable. The rotating ring member is configured to be rotatable relative to a base to which the fixed ring member is connected or connectable. Thus, the rotating ring member is configured to rotate relative to the fixed ring member, for example to allow a crane supported by the rotating ring member to be rotatable about a slew axis.

[0019] In a practical embodiment, the rotating ring member is provided with circumferentially arranged gear teeth which can mesh with a pinion of a rotary drive for rotating the rotating ring member and any object supported thereon.

[0020] Preferably, the fixed ring component and the rotating ring component are made of steel material (eg, chrome-molybdenum alloy steel).

[0021] The raceway member is preferably made of a different metal than the rest of the stationary and rotating ring parts.The raceway member may be made of a metal suitable for contacting and moving relative to rolling elements, such as (cylindrical) rollers.

[0022] For example, the raceway members may be made of hardened steel or of a steel material commercially available under the trademark Hardox.

[0023] Rolling elements (e.g., rollers, such as cylindrical rollers) are arranged between the fixed raceway member and the rotating raceway member to allow the rotating ring member to rotate relative to the fixed ring member and to support the rotating ring member. For example, a plurality of rolling elements are arranged in a cage, and a plurality of cages are arranged in series between the raceway members.

[0024] The slewing bearing further includes an elastically compressible elastic insert, which, for example, includes a plastic material. The elastic insert is clamped between the rotating raceway component and the rotating ring component, so that the rotating ring component is elastically supported on the roller via the rotating raceway and the elastic insert, or the elastic insert is clamped between the fixed ring component and the fixed raceway component, so that the rotating ring component is elastically supported on the roller via the elastic insert and the fixed raceway.

[0025] For example, in the case where the elastic insert is sandwiched between the rotating raceway member and the rotating ring member, since the elastic insert is elastically compressible, the rotating raceway member can be slightly moved relative to the first rotating ring member, for example, due to a load applied to the slewing bearing. Similarly, in the case where the elastic insert is sandwiched between the fixed raceway member and the fixed ring member, the fixed raceway member is allowed to be slightly moved relative to the fixed ring member.

[0026] The slewing bearing further comprises at least one, preferably a plurality of axial load sensors for monitoring the axial load on the slewing bearing by measuring the distance between the rotating ring component and the rotating raceway on the elastic insert, or by measuring the distance between the fixed ring component and the fixed raceway component on the elastic insert. In other words, the axial load sensor is configured to monitor the axial load on the slewing bearing by measuring the distance between the rotating ring component and the rotating raceway component through the elastic insert. In this setting, the axial load sensor does not directly measure the distance between the fixed ring component and the rotating ring component. The axial load sensor also does not contact the gap between the fixed ring component and the rotating ring component, which reduces the possibility of failure of the axial load sensor.

[0027] In practice, the axial load sensor is configured to determine the axial load on the slewing bearing by measuring the distance between the components of the slewing bearing between which the elastic insert is sandwiched, by measuring the local compression of the elastic insert. Since the rotating surface and the fixed surface are perpendicular to the axis of rotation and when the elastic insert is compressed, the raceway components can move in a direction parallel to the axis of rotation, this gives a measure of the local axial load on the slewing bearing.

[0028] In an embodiment, the axial load sensor is configured to measure the distance by measuring the distance between components of the slew bearing between which the insert is sandwiched, by measuring the local compression of the elastic insert based on an electromagnetic field (eg, like an inductive proximity sensor).

[0029] In other embodiments, the axial load sensor is a mechanical contact sensor that extends through the insert, for example via a hole therethrough, and is configured to measure local compression of the resilient insert by measuring the distance between components of the slew bearing between which the insert is sandwiched.

[0030] In an embodiment, the axial load sensor is configured to measure the distance between components of the slew bearing between which the insert is sandwiched by sending a signal through the elastic insert and receiving a reflected signal, thereby measuring the distance by measuring local compression of the elastic insert.

[0031] In an embodiment, a plurality of axial load sensors are provided on the slewing bearing to determine the axial load at a plurality of locations around the circumferential extension of the bearing, thus providing more information about the axial load on the slewing bearing. For example, the axial load sensors are arranged at regular intervals around the circumferential extension of the bearing, such as 10 or more sensors, such as more than 20 sensors, such as at intervals between 10 and 100 centimeters.

[0032] By providing an axial load sensor in a slewing bearing according to the invention, the axial load can be accurately determined using a system that is not affected by effects such as dirt or grease (e.g. comprising metal particles) present between the rotating ring component and the stationary ring component. Furthermore, the system is a robust system because the axial load sensor does not come into contact with the (grease-filled) gap between the surfaces of the bearing components that rotate relative to each other.

[0033] In an embodiment, in order to support the radially directed load between the rotating ring component and the fixed ring component, the slewing bearing further comprises an elastically compressible elastic sliding ring, the elastic sliding ring for example comprising a plastic material, the elastic sliding ring being mounted to the rotating ring component or the fixed ring component and sliding along the second fixed surface of the fixed ring component or along the second rotating surface of the rotating ring component,

[0034] The slewing bearing further comprises a radial load sensor for monitoring the radial load on the slewing bearing by measuring the distance between the rotating ring component and the fixed ring component through the sliding ring.

[0035] The radial load sensor is configured to measure the distance between the rotating ring component and the fixed ring component through the slip ring based on field measurement.

[0036] In an embodiment, the radial load sensor is configured to measure distance by measuring based on an electromagnetic field (eg, like an inductive proximity sensor).

[0037] The elastically compressible resilient sliding ring can be mounted substantially vertically in the slewing bearing to be parallel to the vertical axis of rotation. Movement of the rotating ring component relative to the fixed ring component (for example, as a result of a hoisting load) can cause a radial load to be applied. The elastically compressible resilient sliding ring can be made of the same material as the elastically compressible resilient insert discussed herein. When a radial load is applied, the resilient sliding ring is compressed due to the forces acting on it through the rotating ring component and the fixed ring component. A measurement of the radial load is obtained by measuring the compression of the sliding ring using a radial load sensor.

[0038] The invention also relates to a slewing bearing according to claim 4 .

[0039] In order to support radially directed loads between the rotating ring component and the fixed ring component, the slewing bearing comprises an elastically compressible elastic sliding ring, for example comprising a plastic material, which is mounted to the rotating ring component or the fixed ring component and slides along a fixed surface of the fixed ring component or along a rotating surface of the rotating ring component.

[0040] The slewing bearing further comprises a radial load sensor for monitoring the radial load on the slewing bearing by measuring the distance between the rotating ring component and the fixed ring component through the sliding ring.

[0041] The radial load sensor is configured to measure the distance between the rotating ring component and the fixed ring component through the slip ring based on field measurement.

[0042] The slewing bearing may be provided with a plurality of radial load sensors to measure the radial load at various circumferential positions of the slewing bearing.

[0043] By providing a radial load sensor according to the invention, the radial load can be accurately determined using a system that is not (unduly) affected by external effects such as dirt or grease present between the rotating ring part and the fixed ring part. Furthermore, the system is a robust system because the radial load sensor does not have to be in contact with surfaces that rotate relative to each other.

[0044] In an embodiment, the slew bearing includes both a radial load sensor and an axial load sensor as discussed herein.

[0045] In an embodiment, the elastic insert is sandwiched between the rotating raceway member and the rotating ring component, wherein the axial load sensor is disposed in the rotating ring component, adjacent to the elastic insert, and opposite to the rotating raceway member relative to the elastic insert. This allows the axial load sensor to be disposed inside the body of the rotating ring component, thereby protecting the sensor from external influences.

[0046] In an embodiment, the sliding ring is arranged on the fixed ring component, and the radial load sensor is arranged in the rotating ring component, adjacent to the sliding ring. This allows the radial load sensor to be arranged inside the body of the rotating ring component, thus protecting the sensor from external influences.

[0047] In an embodiment, the axial load sensor is configured to measure the distance between components of the slew bearing between which the insert is sandwiched by sending a signal through the insert and receiving a reflected signal, thereby measuring the distance by measuring local compression of the elastic insert.

[0048] In an embodiment, the radial load sensor is configured to measure the distance between the rotating ring component and the stationary ring component through the slip ring by sending a signal through the slip ring to the opposing surfaces and receiving a reflected signal.

[0049] In an embodiment, the rolling element is a roller, such as a cylindrical roller. The roller is a suitable rolling element for a slewing bearing for supporting a heavy load (e.g., a crane). In other embodiments, the rolling element can be a ball.

[0050] In an embodiment, the slewing bearing comprises a plurality of axial load sensors for monitoring the axial load on the slewing bearing by measuring the distance between the rotating ring member on the elastic insert and the first rotating raceway or by measuring the distance between the fixed ring member on the elastic insert and the first fixed raceway, wherein the plurality of axial load sensors are distributed on a circumferential extension of the slewing bearing around the axis of rotation,

[0051] And / or, wherein the slewing bearing comprises a plurality of radial load sensors for monitoring the radial load on the slewing bearing by measuring the distance between the rotating ring component and the fixed ring component through the sliding ring, wherein the plurality of radial load sensors are distributed around the circumferential extension of the slewing bearing around the slewing axis.

[0052] This embodiment allows measuring the axial load and / or radial load around the circumferential extension of the angular slew bearing. In this way, the load can be monitored around the circumferential extension of the bearing while the crane supports and rotates the load. This allows monitoring the position along the circumferential extension where the peak load is experienced, independently of the position of the peak load along the circumferential extension.

[0053] In an embodiment, the elastic insert and / or the sliding ring are made of a composite material (eg a fiber reinforced plastic material).For example, the elastic insert and / or the sliding ring may be made of Orkot (brand name).

[0054] In an embodiment, the rotating ring component comprises a recess within which the rotating raceway member is received.

[0055] In an embodiment, the fixed ring component is provided with a second fixed raceway member, which forms a second fixed raceway surface oriented substantially perpendicular to the axis of revolution, and wherein the rotating ring component is provided with a second rotating raceway member, which forms a second rotating raceway surface,

[0056] wherein the rolling element (eg, roller) is disposed between the second fixed raceway member and the second rotating raceway member,

[0057] Wherein, the slewing bearing further includes a second elastically compressible elastic insert, which, for example, contains a plastic material. The elastic insert is clamped between the second rotating raceway component and the rotating ring component, so that the rotating ring component is elastically supported on the roller via the second rotating raceway component and the second elastic insert, or the elastic insert is clamped between the fixed ring component and the second fixed raceway component, so that the fixed ring component is elastically supported on the roller via the second elastic insert and the second fixed raceway component.

[0058] In an embodiment, in order to support the radially directed load between the rotating ring component and the fixed ring component, the slewing bearing further includes a second elastically compressible elastic sliding ring, the elastic sliding ring, for example, comprising a plastic material, which is mounted to the rotating ring component or the fixed ring component and slides along the fixed surface of the fixed ring component or along the rotating surface of the rotating ring component.

[0059] In an embodiment, the fourth fixed surface is oriented substantially parallel to the axis of revolution and is arranged opposite the fourth rotating surface,

[0060] The slewing bearing further comprises a second elastically compressible elastic sliding ring, which comprises plastic material, for example, and is arranged on the fourth fixed surface or the fourth rotating surface to support the radially inwardly directed load between the rotating ring component and the fixed ring component.

[0061] In an embodiment, the axial load sensor is configured to measure the distance between the rotating ring component on the elastic insert and the first rotating raceway or the distance between the fixed ring component on the elastic insert and the first fixed raceway by sending a signal through the elastic insert to the opposite surface and receiving a reflected signal.

[0062] The invention further relates to a crane or a backhoe which is rotatably supported on a base by means of a slew bearing according to the invention.

[0063] The invention further relates to a vessel comprising a crane having a toroidal bearing according to the invention, wherein the vessel is configured to perform offshore lifting operations.

[0064] The invention further relates to a method for lifting an object on a vessel using a crane, wherein a vessel according to the invention is used.

[0065] In an embodiment of the method, the method comprises:

[0066] - Lifting objects using a crane mounted on a vessel;

[0067] - monitoring the radial load and / or axial load on the slewing bearing using radial load sensors and axial load sensors; and

[0068] - Optionally, a warning signal is provided when the axial load and / or the radial load exceeds a predetermined threshold value.

[0069] A second aspect of the present invention is directed to an improved assembly for supporting an object on a track, arranged for monitoring the load on the assembly.

[0070] A second aspect of the invention relates to an assembly for supporting an object on a track as the object moves along the track, wherein the assembly comprises a load bearing housing for carrying the object,

[0071] wherein the assembly comprises an endless chain of rolling elements arranged to recirculate along a closed path around a raceway member and a central body of the assembly, the central body being attached to or integral with a load bearing housing, the path comprising:

[0072] a working portion defined by the flat load bearing surface of the raceway member of the assembly in which an operating group of rolling elements engages the track, and

[0073] a return portion defined by a return surface of the central body of the assembly, in which the remaining set of rolling elements is disengaged from the track, for example having a section parallel to the working portion,

[0074] wherein the assembly comprises an elastically compressible elastic insert, for example comprising a plastic material, which is clamped between the central body and the raceway member above the working part, so that the central body is elastically supported on the operating group of rolling elements via the insert and the raceway member,

[0075] Therein, the assembly further comprises a load sensor for monitoring the load on the assembly by measuring the distance between the central body and the raceway member via the elastic insert, wherein the load sensor is arranged in the central body opposite the raceway member relative to the elastic insert, for example.

[0076] When the assembly of the second aspect is used in combination with an XY motion support for a pile holder, as in a preferred embodiment of the second aspect of the invention, the advantage is that the effective height of the XY motion support for the pile holder can be reduced, since large diameter wheels are no longer used for this purpose. This improves the stability of the support of the load on the vessel and the stability of the vessel including the load, for example making it easier to control its positioning. In addition, the track is no longer subject to adverse local mechanical loads at the relatively small interface between the wheel and the track. This can allow the requirements on the mechanical properties of the track to be reduced. In addition, compared with the known arrangement of large diameter wheels, the assembly of the present invention can provide a smooth movement of the load along the track. For example, the stick-slip effect can be reduced to facilitate the control of the precise dynamic positioning of the pile holder, which becomes increasingly challenging as the weight (e.g., of the pile) to be handled increases.

[0077] The track may be mounted or mountable to a surface, such as on top, such as on a ship, such as a deck, with the object being able to move along the track. The track may be mounted to the surface via another such track. The track may alternatively be mounted or mountable to extend laterally, or to be suspended to support the object from above. The term "above" should be interpreted to include such configurations.

[0078] The assembly includes a load bearing housing for carrying an object on the assembly, such as for mounting the object to the assembly. By carrying the object and engaging with the track, the assembly supports the object on the track. In an embodiment, the assembly is suitable for supporting the object on multiple tracks, such as two parallel tracks.

[0079] The assembly comprises an endless chain of steel rolling elements arranged to recirculate along a closed path defined by the assembly. For example, 20 to 25 rolling elements are arranged in the endless chain. The chain is formed by a row of steel rolling elements, the axes of rotation of the rolling elements being parallel to each other, as is known in the art.

[0080] For example, the rolling elements may be physically connected to each other, or may push each other forward via intermediate elements between adjacent rollers.

[0081] The closed path extends around the raceway member and the center body. Therefore, the raceway member and the center body form the inner periphery of the closed path. The path includes a working portion and a return portion. The working portion is defined by the load bearing surface of the raceway member of the assembly, in which the operating group of rolling elements engages the track. Thereby, the working portion supports the load of the object on the track. The load bearing surface is usually smooth, and the raceway member having this surface is non-elastic because it is made of steel. The rolling elements are also made of steel, so that the friction between the rolling elements and the load bearing surface is minimized. In the return portion defined by the return surface of the center body, the remaining group of rolling elements disengages from the track. Therefore, the rolling elements of the remaining group do not engage the track and thus support the object on the track. This can be achieved by extending the return surface directly upward from the load bearing surface at the front and rear sides of the load bearing surface. In the example, the return portion has a section parallel to the working portion.

[0082] In operation, that is to say, when the objects and components are moved in the longitudinal direction of the track, the operating group of rolling elements is moved along the working part of the closed path in the direction opposite to the direction of this movement. In the process, the rolling elements roll on the track and on the load-bearing surface. In the return part of the closed path, the rolling elements are moved along the return part from the side of the working part where the rolling elements leave the working part to the side of the working part where the rolling elements enter the working part. In the process, the rolling elements roll on the return surface.

[0083] The actual shape of the closed path has a working portion that extends longitudinally along a plurality of rolling elements (e.g., 6 to 10 rolling elements) and extends along the top surface of the track when the assembly is engaged with the track, and the actual shape of the closed path has a straight portion of the return portion, for example, of equal length, located above and parallel to the working portion. The straight portion of the return portion and the working portion can be interconnected by semicircular front and rear portions of the closed path. Or, for example, the closed path is in the shape of a rounded rectangle, where the long sides are formed by the working portion and the straight portion of the return portion.

[0084] The assembly may engage the track only from above, however it is preferred that the assembly also restricts movement of the assembly relative to the track in a lateral direction of the track. In an embodiment, the rolling element may be slightly recessed. For example, lateral movement relative to the track may also be restricted by providing one or more elements (e.g., rollers or wheels having a vertical axis of rotation) that engage the track laterally. These may be mounted to the assembly or formed integrally with the assembly.

[0085] The rolling elements may have a hardened surface to further reduce friction at their interface with the rails and load bearing surfaces.

[0086] According to a second aspect of the invention, the assembly comprises an elastically compressible elastic insert between the central body and the steel raceway. The central body is elastically supported on the operating group of rolling elements via the insert.

[0087] The insert may be, for example, an elastically compressible resilient plate, on top of which the load bearing body is attached.

[0088] The central body is preferably attached directly to the elastic insert at its top.

[0089] The assembly is configured to monitor the load on the elastic insert, rather than the load on the rollers. In fact, the load sensor of the assembly is configured to measure the distance between the central body and the raceway member through the elastic insert, thereby determining the load on the central body by measuring the local compression of the elastic insert. This gives a measure of the local load on the assembly. Therefore, the assembly of the second embodiment allows for robust load sensing that is less prone to failure, since the load sensor is not in contact with a closed path that may contain dirt or grease. Furthermore, the sensor can be completely embedded in the steel body, thereby providing a protective housing for the sensor.

[0090] In an embodiment of the second aspect, the resilient insert is made of a composite material, such as a fiber reinforced plastic material.

[0091] In an embodiment of the second aspect, the raceway member and / or the elastic insert are each embodied in the form of a plate.

[0092] The raceway member and the elastic insert may each be implemented in the form of a plate, and the raceway member may have a thickness which corresponds to less than, for example, approximately 55-65% of the thickness of the raceway member.

[0093] In an embodiment of the second aspect, the central body comprises a recess in which the elastic insert and the raceway element are housed and axially closed, for example such that the raceway element is flush with a longitudinally adjacent return surface of the central body.

[0094] In an embodiment of the second aspect, at the front and rear sides of the load bearing surface, the return surface extends directly upwards from the load bearing surface, preferably wherein the frontmost section and / or the rearmost section of the raceway member is slightly inclined upwards towards the return surface.

[0095] In an embodiment of the second aspect, the component further includes a second endless chain of linear recycling rolling elements, which is arranged to recirculate along a second closed path defined by the component, the two paths are laterally juxtaposed and parallel to each other, the second path includes a working part and a return part, the working part is defined by the second load-bearing surface of the second raceway member, and in the working part, the operating group of the rolling elements engages the track, the return part is defined by the second return surface of the center body, and in the return part, the remaining group of rolling elements disengages from the track, wherein the center body is elastically supported on the corresponding operating parts of the rolling elements of the two endless chains via corresponding raceway members and an elastically compressible elastic sliding ring (for example, comprising plastic material) clamped between the center body and the second raceway member.

[0096] In an embodiment of the second aspect, the housing is provided with one or more seals around at least the working portion of the recirculating rolling element, for example between one or more bottom surfaces of the assembly (for example, the bottom surface of a wall of the assembly) and the upper surface of the track, the bottom surfaces of the walls of the assembly together axially enclosing the working portion,

[0097] Therein, the seal defines, for example together with the wall, a grease chamber between the load bearing surface and the upper surface of the track for an operating group of recirculating rolling elements, for example, wherein the seal is substantially V-shaped in cross section.

[0098] In an embodiment of the second aspect, the housing is provided with one or more front and / or rear scrapers or brushes, respectively, at the front and / or rear sides facing the longitudinal direction of the rail and at a longitudinal distance from the working portion, engaging the upper surface of the rail for cleaning the rail.

[0099] In an embodiment of the second aspect, the shell includes front and rear vertical end walls and front and rear guide walls, wherein the front and rear vertical end walls extend laterally on the front and rear sides of the component, respectively, and the front and rear guide walls are attached to the front and rear end walls, respectively, and respectively define a front section and a rear section of the return portion of the closed path relative to the return surface, for example, wherein the attachment is established via one or more slender mounting elements (for example, one or more bolts, screws or the like), which extend vertically through the end walls and protrude longitudinally into the guide walls.

[0100] In an embodiment of the second aspect, the shell includes a second front guide wall and a second rear guide wall, which are respectively attached to the front and rear end walls and respectively define a front section and a rear section of the return portion of the second closed path opposite to the second return surface.

[0101] In an embodiment of the second aspect, the shell further includes a front and / or rear frame, which protrudes from the front and / or rear end wall in the forward and / or rearward direction, respectively, wherein the front and / or rear scraper is installed below the longitudinal end of the corresponding frame.

[0102] In an embodiment of the second aspect, the rolling elements each rotate about a respective roller axle, the head end of the roller axle extending on a respective tread formed by a vertical protrusion extending longitudinally along the closed path from the central body at a respective lateral side of the closed path.

[0103] In an embodiment of the second aspect, the component further includes upper left and lower and upper right and lower longitudinal wall parts, which form upper and lower vertical protrusions from the center body at the left and right ends and extend longitudinally over at least the length of the closed path, for example, wherein the upper left and lower longitudinal wall parts are connected to each other via one or more slender mounting elements (for example, one or more bolts, screws or the like), and the upper right and lower longitudinal wall parts are connected to each other via one or more slender mounting elements (for example, one or more bolts, screws or the like), and one or more slender mounting elements extend vertically inside the corresponding upper and lower longitudinal wall parts and pass through the corresponding lateral ends of the center body, for example, multiple slender mounting elements are distributed longitudinally along the wall parts.

[0104] In an embodiment of the second aspect, the component further includes middle upper and lower longitudinal wall parts, which form upper and lower vertical protrusions from the center body between the two closed paths and extend longitudinally along at least the length of the closed path, for example, wherein the middle upper and lower longitudinal wall parts are connected to each other via one or more slender mounting elements (for example, one or more bolts, screws or the like), and one or more slender mounting elements extend vertically inside the corresponding upper and lower longitudinal wall parts and pass through the middle of the center body, for example, multiple slender mounting elements are distributed longitudinally along the wall parts.

[0105] In an embodiment of the second aspect, the longitudinal wall member is connected to the end wall via one or more elongated mounting elements extending vertically through the end wall and protruding longitudinally into the longitudinal wall member.

[0106] In an embodiment of the second aspect, the assembly includes a plurality of load sensors for monitoring the load on the assembly by measuring the distance between the center body and the raceway member, wherein the plurality of axial load sensors are distributed on the center body. BRIEF DESCRIPTION OF THE DRAWINGS

[0107] The present invention will now be described with reference to the accompanying drawings, in which:

[0108] Figure 1 A crane equipped with a slewing bearing is shown in cross section;

[0109] Figure 2 A portion of a first embodiment of a slew bearing is shown in more detail;

[0110] Figure 3 shows a cross section of a portion of a second embodiment of a slew bearing; and

[0111] Figure 4 Shown is a cross section of an assembly according to the second aspect of the invention. DETAILED DESCRIPTION

[0112] The slewing bearing 1 is configured to support an object 100 (here a slewing crane of a marine vessel) rotatably about a slewing axis on a base (here a crane barrel 150 ). Figure 1 The person shown indicates the dimensions of the slewing bearing 1 in this example. In this example, the person stands outside the slewing bearing 1 .

[0113] The slew bearing 1 comprises a fixed ring part 2, known in the art as a nose part, which is connected or connectable to a foundation 150, for example of a vessel.

[0114] The slewing bearing 1 further comprises a rotating ring component 3 which can be connected or coupled to a crane 100 or other objects.

[0115] Once mounted on the slewing bearing 1 , the crane 100 can be rotated about the slewing axis by a rotational movement of the rotating ring part 3 relative to the fixed ring part 2 .

[0116] In a practical embodiment, the component 2 has an internal gear section 2 a (as shown here) or an external gear section 2 a formed by circumferentially arranged teeth which can mesh with a pinion driven by a motor to perform a rotary movement.

[0117] exist Figure 2 The slewing bearing 1 is shown in more detail in FIG.

[0118] The first fixed raceway surface 4 is oriented substantially perpendicularly to the axis of revolution, which is located at Figure 1 Usually extends vertically.

[0119] The first raceway fixed surface 4 is arranged opposite to the first rotating raceway surface 5 , and the first rotating raceway surface 5 is parallel to the first fixed raceway surface 4 .

[0120] The surface 4 is formed by a first fixed raceway member 6 and is in contact with rolling elements 9 of a slew bearing, for example rollers 9 , for example cylindrical rollers 9 .

[0121] The first rotating surface 5 is formed by a first rotating raceway member 7 .

[0122] The rolling elements 9 are disposed between the first fixed raceway member 6 and the first rotating raceway member 7 .

[0123] The slewing bearing 1 includes a first elastically compressible elastic insert 8, which is sandwiched between the first rotating raceway member 7 and the rotating ring member 3, so that the rotating ring member 3 is elastically supported on the rolling element 9. In other embodiments, the first insert 8 is sandwiched between the fixed ring member 2 and the first fixed raceway member 6, so that the rotating ring member 3 is elastically supported on the rolling element 9 via the elastic insert 8 and the first fixed raceway 6.

[0124] The resilient insert 8 may be made of a composite material, such as a fibre reinforced plastic material, such as Orkot (brand name).

[0125] The slewing bearing 1 comprises an axial load sensor 10, which is arranged in the rotating ring part 3 for monitoring the axial load on the slewing bearing 1 by measuring the distance between the rotating ring part 3 and the first rotating raceway member 7 on the elastic insert 8. The distance is measured by the axial load sensor 10 through the first insert 8, for example, by measuring the magnetic flux generated by the change in position of the first rotating raceway member 7 relative to the load sensor 10 due to the compression of the insert 8. For example, the sensor 10 is implemented as an inductive proximity sensor.

[0126] In other embodiments, the load sensor 10 may be in mechanical contact with the first rotating raceway member 7 through the first insert 8 to measure the distance, for example the insert 8 has a corresponding hole through which the sensor 10 or a part of the sensor 10 extends.

[0127] In the embodiment, the first insert 8 is sandwiched between the fixing ring component 2 and the first fixing raceway member 6 , and the load sensor 10 may be disposed in the fixing ring component 2 to measure the distance between the fixing ring component 2 and the first fixing raceway member 6 on the first insert 8 .

[0128] Preferably, the slewing bearing 1 comprises a plurality of axial load sensors 10 for monitoring the axial load on the slewing bearing 1. The plurality of axial load sensors 10 are distributed on the circumferential extension of the slewing bearing 1 around the axis of rotation, for example, more than 10 axial load sensors are provided in combination with a single raceway member of the slewing bearing, for example, more than 20 axial load sensors. This allows monitoring the load around the circumferential extension, showing the position of the peak load on the slewing bearing 1, regardless of the position of the peak load on the circumferential extension.

[0129] Axial load sensing may be performed by measuring the distance between the rotating ring component 3 and the first rotating raceway member 7 on the elastic insert 8 , or by measuring the distance between the fixed ring component 2 and the first fixed raceway 6 on the elastic insert 8 .

[0130] Figure 1 The slewing bearing 1 shown further comprises an elastically compressible elastic sliding ring 13, for example made of the same material as the first insert 8, which is mounted to the vertical surface 11 of the ring member 2. The rotating surface 12 of the ring member 3 slides along this sliding ring 3 so as to support radially directed loads between the fixed ring member 2 and the rotating ring member 3.

[0131] Figure 1 The slew bearing 1 shown further comprises a second fixed surface 16 formed by a second fixed raceway member 17 , the second fixed surface 16 being oriented perpendicularly to the slew axis.

[0132] The second rotating raceway member 18 forms a second rotating surface 15 provided on the rotating ring component 3 .

[0133] The rolling elements 9 (eg, rollers 9 ) are provided between the second fixed raceway member 17 and the second rotating raceway member 18 .

[0134] The slewing bearing 1 as shown here may also comprise a second elastically compressible elastic insert 19 , for example made of the same material as the first insert 8 , which is sandwiched between the second stationary raceway component 17 and the stationary ring part 2 .

[0135] One or preferably more second axial load sensors may be provided to measure the distance between the second stationary raceway member 17 and the stationary ring part 2 through the insert 19 .

[0136] Figure 2The slewing bearing 1 further comprises a fixed surface 20 on the fixed ring member 2, the fixed surface 20 being oriented parallel to the slewing axis. The fixed surface 20 is arranged opposite to a rotating surface 21 provided on the rotating ring member 3.

[0137] A second elastically compressible sliding ring 22 is arranged between the surfaces 20 , 21 in order to support radially directed loads between the rotating ring part 3 and the fixed ring part 2 .

[0138] Figure 3 Shown with Figure 1 Different embodiments of a slew bearing 1 , in which similar elements are provided with the same reference numerals.

[0139] Figure 3 The slewing bearing 1 shown further comprises one or more, preferably a plurality of, radial load sensors 14 for monitoring the radial load on the slewing bearing 1. The radial load is monitored by measuring the distance between the rotating ring part 3 and the fixed ring part 2 via the second insert 13. The distance is measured based on the measurement of a field (e.g. an electromagnetic field, a magnetic field, e.g. a magnetic flux) or a signal emitted by the load sensor and reflected towards the load sensor.

[0140] For example, the sensor 14 is an inductive proximity sensor.

[0141] In an embodiment, the slewing bearing 1 includes a plurality of radial load sensors 14 for monitoring the radial load on the slewing bearing 1 by measuring the distance between the rotating ring component 3 and the fixed ring component 2 through the sliding ring 13, wherein the plurality of radial load sensors 14 are distributed around the circumferential extension of the slewing bearing 1 around the slewing axis.

[0142] The slewing bearing 1 shown in the drawings can rotatably support the crane on a base. The base of the crane can be arranged on a ship so that the crane can be used to perform offshore activities, such as lifting objects.

[0143] For example, a crane provided on a vessel may be used in a method comprising:

[0144] - Lifting objects using a crane mounted on a vessel;

[0145] - monitoring the radial load and / or axial load on the slewing bearing using radial load sensors and axial load sensors; and

[0146] - Optionally, a warning signal is provided when the axial load and / or the radial load exceeds a predetermined threshold value.

[0147] Figure 4There is shown a cross section of an assembly 30 according to the second aspect of the invention. The assembly 30 is adapted to support an object on a track 31 as the object moves along the track, wherein the assembly 30 comprises a load bearing housing 39 for carrying the object.

[0148] The assembly 30 comprises an endless chain of rolling elements 32, for example a chain of cylindrical steel rollers 32, arranged to recirculate along a closed path 33 around raceway members 34 and a central body 35 of the assembly 30. The central body is attached to or integral with a load bearing housing 39, not shown in the figures.

[0149] The closed path 33 includes a working portion 36 defined by the flat load bearing surface of the raceway member 34 of the assembly 30. In the working portion 36, the operating set of rolling elements 32 engages the track 31.

[0150] The closed path 33 further comprises a return portion 37, which is defined by a return surface of a central body 35 (e.g., a steel central body) of the assembly 30, in which the remaining set of rolling elements 32 are disengaged from the track 31, for example, the return portion 37 having a section parallel to the working portion 36, such as Figure 3 shown.

[0151] The assembly 30 further comprises an elastically compressible elastic insert 38, for example comprising a plastic material, for example made of the same material as the insert of the first aspect of the invention, for example made of Orkot (brand name). The elastic insert 38 is sandwiched between the central body 35 and the raceway member 34 above the working portion 36. This allows the central body 35 to be elastically supported on the operating group of rolling elements 32 via the insert 38 and the raceway member 34.

[0152] The assembly 30 further includes a load sensor 40 for monitoring a load on the assembly 30, such as a load resulting from supporting an object thereon. The load sensor 40 monitors the load by measuring the distance between the central body 35 and the raceway member 34 through the insert 38. As the insert 38 is compressed due to the load, the distance changes, such that the distance can be used to measure the load applied to the assembly 30. The load sensor 40 is disposed in the central body 35, for example, relative to the resilient insert 38 and the raceway member 34. The load sensor 40 can be implemented as discussed herein for other load sensors, such as an inductive proximity sensor.

[0153] In an embodiment, assembly 30 includes a plurality of load sensors 40 distributed on center body 35 to measure the load thereon. This allows monitoring of the load distributed on assembly 30, giving a more complete picture of the loads (eg, peak loads) during operation.

[0154] The track 31 may be mounted or mountable to a surface, such as on a roof, such as on a ship, such as a deck, while objects can be moved along the track 31 .

[0155] The assembly 30 includes a load bearing housing 39 for carrying an object on the assembly 30, for example, for mounting the object to the assembly. By carrying the object and engaging with the track 31, the assembly 30 supports the object on the track 31, thereby generating a load thereon. In an embodiment, the assembly 30 is suitable for supporting an object on a plurality of tracks 31, for example, two parallel tracks 31.

[0156] The assembly comprises an endless chain of steel rolling elements 32 arranged to recirculate along a closed path 33 defined by the assembly 30. For example, 20 to 25 rolling elements 32 are arranged in the endless chain. The chain is formed by a row of rolling elements 32 (for example, steel rolling elements 32) whose axes of rotation are parallel to each other, as is known in the art.

[0157] For example, the rolling elements 32 may be physically connected to each other, or may push each other forward via an intermediate element between adjacent rolling elements 32 .

[0158] In operation, that is to say, when the object and assembly 30 are moved in the longitudinal direction of the track 31, the operating group of rolling elements 32 is moved in the opposite direction of this movement along the working portion 36 of the closed path 33. In the process, the rolling elements 32 roll on the track 31 and on the load bearing surface. In the return portion 37 of the closed path 33, the rolling elements 32 are moved along the return portion 37 from the side of the working portion 36 where the rolling elements 32 leave the working portion 36 to the side of the working portion 37 where the rolling elements enter the working portion. In the process, the rolling elements 32 roll on the return surface.

[0159] The assembly 30 is configured to monitor the load on the elastic insert 38 using a load sensor 40. In practice, the load sensor 40 of the assembly 30 is configured to measure the distance between the central body 35 and the raceway member 34 through the elastic insert 38, thereby determining the load on the central body 35 by measuring the local compression of the elastic insert. This gives a measurement of the local load on the assembly 30. Therefore, the assembly of the second embodiment allows a robust load sensing that is less prone to failure, because the load sensor is not in contact with the closed path 33 that may contain dirt or grease. In addition, the sensor 40 can be completely embedded in the steel body, thereby providing a protective housing for the sensor. The load sensor 40 can measure the compression of the insert based on magnetic flux (for example, due to the displacement of the magnetized portion of the raceway member 34), by reflection of the signal emitted by the load sensor 40 on the raceway member 34, via direct contact between the load sensor 40 and the raceway member 40, or in any other way.

Claims

1. A slewing bearing (1) for supporting an object (100) rotatably about a slewing axis on a base, for example a crane or a crane component on a base (150), wherein: The slewing bearing (1) comprises: - a fixing ring member (2) connected or connectable to said base (150); and a rotating ring member (3) which is connected or can be connected to an object (100) which can rotate around an axis of revolution, The fixed ring component (2) is provided with a fixed raceway member (6), which forms a fixed raceway surface (4) oriented substantially perpendicularly to the rotation axis. The rotating ring component (3) is provided with a rotating raceway member (7), the rotating raceway member (7) forming a rotating raceway surface (5), A rolling element (9), such as a roller, such as a rolling element (9) in a cage, is arranged between a fixed raceway surface (4) and a rotating raceway surface (5), such as the fixed raceway surface (4) is parallel to the rotating raceway surface (5), The slewing bearing (1) further comprises an elastic insert (8) capable of elastic compression, the elastic insert (8) comprising, for example, a plastic material, the elastic insert (8) being sandwiched between the rotating raceway component (7) and the rotating ring component (3), so that the rotating ring component (3) is elastically supported on the rolling element (9) via the rotating raceway component (7) and the elastic insert (8), or the elastic insert (8) being sandwiched between the fixed ring component (2) and the fixed raceway component (6), so that the rotating ring component (3) is elastically supported on the rolling element (9) via the elastic insert (8) and the fixed raceway component (6), And wherein the slewing bearing (1) further comprises an axial load sensor (10) for monitoring the axial load on the slewing bearing (1) by measuring the distance between the rotating ring component (3) on the elastic insert (8) and the first rotating raceway component (7), or by measuring the distance between the fixed ring component (2) on the elastic insert (8) and the first fixed raceway component (6).

2. The slewing bearing according to claim 1, wherein: The axial load sensor (10) is configured to measure distance based on the measurement of a field, such as an electromagnetic field, for example, the axial load sensor (10) is an inductive proximity sensor.

3. The slewing bearing according to claim 1 or 2, wherein: In order to support radially directed loads between the rotating ring component (3) and the fixed ring component (2), the slewing bearing (1) further comprises an elastic sliding ring (13) capable of elastic compression, the elastic sliding ring (13) comprising, for example, a plastic material, the elastic sliding ring (13) being mounted to the rotating ring component (3) or the fixed ring component (2) and sliding along the second fixed surface (11) of the fixed ring component (2) or along the second rotating surface (12) of the rotating ring component (3). The slewing bearing (1) further comprises a radial load sensor (14) for monitoring the radial load on the slewing bearing (1) by measuring the distance between the rotating ring component (3) and the fixed ring component (2) through the sliding ring (13). The radial load sensor (14) is configured to measure the distance between the rotating ring component (3) and the fixed ring component (2) through the sliding ring (13) based on field measurement.

4. A slewing bearing (1) for supporting an object (100) rotatably about a slewing axis on a base (150), for example a crane or a crane component on a base (150), wherein: The slewing bearing (1) comprises: - a fixing ring member (2) which is connected or connectable to the base (150); and a rotating ring member (3) which is connected or can be connected to an object (100) which can rotate around an axis of revolution, In order to support the radially directed load between the rotating ring component (3) and the fixed ring component (2), the slewing bearing (1) comprises an elastic sliding ring (13) capable of elastic compression, the elastic sliding ring (13) for example comprising a plastic material, the elastic sliding ring (13) being mounted to the rotating ring component (3) or the fixed ring component (2) and sliding along a fixed surface (20) of the fixed ring component (2) or along a rotating surface (21) of the rotating ring component (3), The slewing bearing (1) further comprises a radial load sensor (14) for monitoring the radial load on the slewing bearing (1) by measuring the distance between the rotating ring component (3) and the fixed ring component (2) via the sliding ring (13). The radial load sensor (14) is configured to measure the distance between the rotating ring component (3) and the fixed ring component (2) through the slip ring (13) based on the measurement of a field, such as an electromagnetic field.

5. The slewing bearing according to any one of claims 1 to 3, wherein: The elastic insert (8) is sandwiched between the rotating raceway component (7) and the rotating ring component (3), the axial load sensor (10) is configured to measure the distance between the rotating ring component (3) and the rotating raceway component (7) on the elastic insert (8), and wherein the axial load sensor (10) is arranged in the rotating ring component (3), adjacent to the elastic insert (8), and opposite to the rotating raceway component (7) relative to the elastic insert (8).

6. The slewing bearing according to claim 3 or 4, wherein: The sliding ring (13) is arranged on the fixed ring part (2), and wherein the radial load sensor (14) is arranged in the rotating ring part (3) adjacent to the sliding ring (13).

7. Slewing bearing according to one or more of the preceding claims, wherein: The axial load sensor (10) is configured to measure distance by sending a signal through the elastic insert (8) and receiving a reflected signal, and / or The radial load sensor (14) is configured to measure the distance by sending a signal through the slip ring (13) and receiving a reflected signal.

8. Slewing bearing according to one or more of the preceding claims, wherein: The rolling elements (9) are rollers (9).

9. The slewing bearing according to one or more of the preceding claims, comprising a plurality of said axial load sensors (10) for monitoring the axial load distribution on the slewing bearing (1) by respectively measuring the distance on the elastic insert (13), wherein: A plurality of axial load sensors (10) are distributed around the rotary axis on a circumferential extension of the rotary bearing (1). and / or The slewing bearing (1) comprises a plurality of radial load sensors (14) for monitoring the radial load distribution on the slewing bearing (1) by measuring the distance through a sliding ring (13), and the plurality of radial load sensors (14) are distributed around the circumferential extension of the slewing bearing (1) around the slewing axis.

10. Slewing bearing according to one or more of the preceding claims, wherein: The elastic insert (8) and / or the sliding ring (13) are made of a composite material, for example a fiber-reinforced plastic material.

11. Slewing bearing according to one or more of the preceding claims, wherein: The rotating ring component (3) comprises a recessed portion, and a rotating raceway member (7) is accommodated in the recessed portion.

12. Slewing bearing according to one or more of the preceding claims, wherein: The fixed ring part (2) is provided with a second fixed raceway member (17) which forms a second fixed raceway surface (16) oriented substantially perpendicularly to the axis of revolution, and wherein the rotating ring part (3) is provided with a second rotating raceway member (18) which forms a second rotating raceway surface (15), wherein rolling elements (9), such as rollers, are arranged between the second fixed raceway member (16) and the second rotating raceway member (16), The slewing bearing (1) further comprises a second elastically compressible elastic insert (19), the elastic insert (19) comprising, for example, a plastic material, the elastic insert (19) being sandwiched between the second rotating raceway component (18) and the rotating ring component (3), so that the rotating ring component (3) is elastically supported on the roller (9) via the second rotating raceway component (18) and the second elastic insert (19), or the elastic insert (19) being sandwiched between the fixed ring component (2) and the second fixed raceway component (15), so that the fixed ring component (2) is elastically supported on the roller (9) via the second elastic insert (19) and the second fixed raceway component (15).

13. Slewing bearing according to one or more of the preceding claims, wherein: In order to support the radially directed load between the rotating ring component (3) and the fixed ring component (2), the slewing bearing (1) further comprises a second elastically compressible elastic sliding ring (22), the elastic sliding ring (22) for example comprising a plastic material, the elastic sliding ring (22) being mounted to the rotating ring component (3) or the fixed ring component (2) and sliding along the fixed surface (20) of the fixed ring component (2) or along the rotating surface (21) of the rotating ring component (3).

14. Crane, which is rotatably supported on a foundation (150) by means of a slewing bearing (1) according to one or more of claims 1 to 13.

15. Backhoe supported on a base (150) by means of a slewing bearing (1) according to one or more of claims 1 to 13.

16. Vessel provided with a crane according to claim 14 or a backhoe dredger according to claim 15.

17. A method for lifting an object (100) using a crane, wherein: Use of a vessel according to claim 16 or a crane according to claim 14.

18. The method according to claim 17, comprising: - lifting the object (100) using, for example, a crane mounted to the vessel; - monitoring the radial load and / or axial load on the slewing bearing (1) using a radial load sensor (10) and an axial load sensor (14); and - Optionally, a warning signal is provided when the axial load and / or the radial load exceeds a predetermined threshold value.

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