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Showing papers on "Slewing bearing published in 2013"


Journal ArticleDOI
TL;DR: In this article, a very low rotational-speed slewing bearing (1-4.5 rpm) without artificial fault was used to detect outlier race fault and rolling element fault.
Abstract: There have been extensive studies on vibration based condition monitoring, prognosis of rotating element bearings; and reviews of the methods on how to identify bearing fault and predict the final failure reported widely in literature. The investigated bearings commonly discussed in the literatures were run in moderate and high rotating speed, and damages were artificially introduced e.g. with artificial crack or seeded defect. This paper deals with very low rotational-speed slewing bearing (1–4.5 rpm) without artificial fault. Two real vibration data were utilized, namely data collected from lab slewing bearing subject to accelerated life test and from a sheet metal company. Empirical mode decomposition (EMD) and ensemble empirical mode decomposition (EEMD) were applied in both lab slewing bearing data and real case data. Outer race fault (BPFO) and rolling element fault (BSF) frequencies of slewing bearing can be identified. However, these fault frequencies could not be identified using fast Fourier transform (FFT).

61 citations


Proceedings ArticleDOI
09 Jul 2013
TL;DR: Findings suggest that the largest Lyapunov exponent, fractal dimension, correlation dimension, and approximate entropy methods provide superior descriptive information about bearing condition than time-domain features extraction, such as root mean square, variance, skewness and kurtosis.
Abstract: This paper presents the application of four nonlinear methods of feature extraction in slewing bearing condition monitoring and prognosis: these are largest Lyapunov exponent, fractal dimension, correlation dimension, and approximate entropy methods. Although correlation dimension and approximate entropy methods have been used previously, the largest Lyapunov exponent and fractal dimension methods have not been used in vibration condition monitoring to date. The vibration data of the laboratory slewing bearing test-rig run at 1 rpm was acquired daily from February to August 2007 (138 days). As time progressed, a more accurate observation of the alteration of bearing condition from normal to faulty was obtained using nonlinear features extraction. These findings suggest that these methods provide superior descriptive information about bearing condition than time-domain features extraction, such as root mean square (RMS), variance, skewness and kurtosis.

48 citations


Journal ArticleDOI
TL;DR: In this paper, a new computational model for determination of internal contact forces distribution and consequently the determination of acceptable load curves for static load capacity in three-row roller slewing bearings is presented.

26 citations


Journal ArticleDOI
TL;DR: In this article, several methods are proposed to account for the flexibility of rings in a quasi-static ball bearing numerical model, such as ring ovalization, ring twist, and raceway opening.
Abstract: In many applications, such as four-point contact slewing bearings or main shaft angular contact ball bearings, the rings and housings are so thin that the assumption of rigid rings does not hold anymore. In this paper, several methods are proposed to account for the flexibility of rings in a quasi-static ball bearing numerical model. The modeling approach consists of coupling a semianalytical approach and a finite element (FE) model to describe the deformation of the rings and housings. The manner in which this weak coupling is made differs depending on how the structural deformation of the ring and housing assemblies is injected into the set of nonlinear geometrical and equilibrium equations in order to solve them. These methods enable us to account for ring ovalization, ring twist, and raceway opening (including change of conformity) since a tulip deformation mode of the ring groove is observed for high contact angles. Either the torus fitting technique or mean displacement computation are used to determine these geometrical parameters. A comparison between the different approaches allows us to study, in particular, the impact of raceway conformity change. The loads used in this investigation are chosen in order that the maximum contact pressure (the Hertz pressure) at the ball-raceway interface remains below 2000 MPa, without any contact ellipse truncation. For the ball bearing example considered here, relative differences of up to 30% on the axial displacement, 10% on the maximum contact pressure, and 10% on the contact angle are observed by comparing rigid and deformable rings for a typical loading representative of the one encountered in operation. Despite the local change of conformity, which becomes significant at high contact angles and for thin ball bearing flanges, it is shown that this hardly affects the internal load distribution. The paper ends with a discussion on how the ring and housing flexibility may affect the loading envelope when the truncation of the contact ellipse is an issue.

26 citations


Journal ArticleDOI
TL;DR: In this article, a generalization of the works by Sjovall and Rumbarger was presented, providing an acceptance surface of the bearing in the load space, considering the influence of the variability of the contact angle with the applied load and as a result, the acceptance surface has been redefined.
Abstract: Four-contact-point slewing bearings are widely used in wind turbine generators (WTGs) to adjust the orientation of the blades and the nacelle to fully exploit wind resources. These bearings must withstand static and fatigue loads; however, at the first stages of the design process, the bearings are commonly selected by considering only static loads. This paper presents a further step of a previous theoretical work published by the authors in the field of the static load-carrying capacity of four-contact-point slewing bearings under axial, radial and tilting-moment loads. In that work, a generalization of the works by Sjovall and Rumbarger was presented, providing an acceptance surface of the bearing in the load space. The contact angle of the balls was assumed to be load independent. The present work improves that development by considering the influence of the variability of the contact angle with the applied load, and as a result, the acceptance surface has been redefined. By comparing the results with those of the finite element model published by the authors, it is proven that the new model presented in this work is more realistic than the previous one. Thus, it is believed that this methodology can be easily applied for the initial selection of blade and yaw bearings in WTGs. Copyright © 2012 John Wiley & Sons, Ltd.

25 citations


Journal ArticleDOI
TL;DR: In this article, a calculation procedure for determination of dynamic load capacity of large three-row roller slewing bearings is presented. The calculation procedure consists of three main parts: (i) determination of internal contact force distribution in a large threerow roller Slewing bearing with consideration of bearing clearances and ring support deformations, (ii), determination of stress field in the contact area between raceway and rollers as a consequence of contact forces and (iii) determination, bearing fatigue life due to contact fatigue of the raceway.

24 citations


Journal Article
TL;DR: In this paper, the influence of the superstructure and undercarriage stiffness on the ball loads in the new bearing after a short operation time was determined, and the load distribution in terms of plastic wear was determined.
Abstract: Original scientific paper Large diameter slewing bearings used in open cast machines are made of unhardened raceways. As a consequence the major wear is caused by the plastic deformations. Loads acting on the rolling elements of the bearing depend on the load transferred through the bearing itself and on the superstructure and undercarriage components stiffness. As a consequence of the plastic wear, the load distribution in the bearing is changing. The object of investigations was slewing bearing of the stacker-reclaimer LZKS 1600 which operates on the coal homogenization yard in open cast mine Belchatow, Poland. Numerical and experimental research was carried out with the purpose to determine the influence of the superstructure and undercarriage stiffness on the ball loads in the new bearing after a short operation time. Moreover, the load distribution in terms of plastic wear was determined.

18 citations


Patent
19 Jul 2013
TL;DR: In this paper, a slewing bearing with two rings and rollers arranged between the rings is described, where one of the rings has a throughhole for inserting the rollers for assembly and maintenance, and with a plug for closing the through-hole.
Abstract: A slewing bearing having two rings and rollers arranged between the rings, wherein one of the rings is provided with a through-hole for inserting the rollers for assembly and maintenance, and with a plug for closing the through-hole. The through-hole is formed as a bore including an inner portion with a smaller bore diameter and an outer portion with a larger bore diameter. The smaller diameter portion is reduced in order to facilitate the assembly, while avoiding an increased diameter in the innermost part of the thorough hole in order to secure stability and robustness.

16 citations


Journal ArticleDOI
TL;DR: In this paper, the authors discuss the calculation problem of the real carrying capacity of slewing bearings and propose a mathematical model of a bearing for the limiting load of the bearing traces and the limiting tension of the bolts fastening the bearing.
Abstract: Purpose – The purpose of this paper is to discuss the calculation problem of the real carrying capacity of slewing bearings. The selection of slewing bearing to heavy-duty machine according to catalogue carrying capacity and also according to locally determined real carrying capacity is insufficient and it can be the cause of the damage of machine during exploitation. Design/methodology/approach – The concepts of the local, total and general capacities is defined. The general capacity is a logical product of the local capacities. It is particularly useful in an analysis of slewing bearings incorporated into machines with complex structures. The FEM is applied in computations. The formation method of the mathematical model of a bearing is presented. Findings – The computations of the local capacities and general capacity of a bearing for the limiting load of the bearing traces and the limiting tension of the bolts fastening the bearing were carried out. Considerations were illustrated by an example of the ...

16 citations


Patent
15 May 2013
TL;DR: In this paper, a large-scale forging and manufacturing process for wind electricity slewing bearing forging and a manufacturing process is described. But the authors focus on the manufacturing process and do not consider the normalizing and tempering effects.
Abstract: The invention relates to a large-scale forging and manufacture process wind electricity slewing bearing forging and a manufacture process, the manufacture process comprises the following steps: selecting materials, blanking, heating, forging, performing thermal treatment after forging, front machining, rear machining, performing physical and chemical inspection, ultrasonic flaw detection, performing finish machining, cleaning and packaging. The first normalising temperature is higher than second normalising temperature, the second normalising can not destroy the first normalising effect, the structure refinement effect is more obvious; normalising adopts heating by segments, the second segment heating reduce the difference of temperature between surface and core on the basis of first segment heating, the thickness direction structure of the large-scale forging and manufacture process wind electricity slewing bearing forging is fine and uniform, the heat treatment employs heating by segments, and the normalising and tempering technical effect can be further guaranteed, and the requirements that elongation percentage is greater than or equal to 13 and the transverse plane shrinkage is greater and equal to 55 can be guaranteed.

13 citations


Patent
09 Oct 2013
TL;DR: In this paper, the authors presented a slewing bearing ferrule circular degree error automatic detection and correction device, which consists of a lathe bed, ferrule supporting and slewing driving devices, circular degree detection devices and a data collecting operation and display system.
Abstract: The invention provides a slewing bearing ferrule circular degree error automatic detection and correction device, and belongs to the technical field of industrial detection and correction. The slewing bearing ferrule circular degree error automatic detection and correction device comprises a lathe bed, ferrule supporting and slewing driving devices, circular degree error detection devices, circular degree error correction devices, lifting and warping-resisting devices and a data collecting operation and display system. The ferrule supporting and slewing driving devices support a slewing bearing ferrule to rotate for one circle, the data collecting operation and display system collects the data output by the circular degree detection devices, the circular degree error values, the correction positions and the correction strokes can be obtained, and the circular degree error correction devices automatically carry out pressure correction according to the calculated results. According to the slewing bearing ferrule circular degree error automatic detection and correction device, the lifting and warping-resisting devices are adopted so that interferences between detection and correction and planar warping of the ferrule can be avoided, three eddy-current sensors are adopted in the circular degree error detection devices, the discretion fast Fourier transform is carried out on the collected signals so that the interferences of the eccentric errors of the slewing bearing ferrule can be eliminated, and the detection accuracy is improved.

Patent
25 Dec 2013
TL;DR: In this paper, an automatic brick setting machine consisting of a portal frame, a sliding platform and a lifting platform, a plurality of green brick fixtures are arranged below the lifting platform and mounted on a base.
Abstract: The invention discloses an automatic brick setting machine which comprises a portal frame. A slidable lifting mechanism is arranged on the portal frame and comprises a sliding platform and a lifting platform, a plurality of green brick fixtures are arranged below the lifting platform and mounted on a base, a slewing mechanism is arranged between the base and the lifting platform and comprises a slewing bearing and a cylinder, the slewing bearing is lifted by a connecting sleeve below the lifting platform, the cylinder is arranged between the slewing bearing and the base, the base is lifted by the slewing bearing and can be driven by the cylinder to horizontally rotate, and a deceleration buffering device and a rotation limiting device are matched with the slewing bearing. The slewing mechanism is driven by the cylinder, transmission gap is eliminated, rotation precision is improved, and rotation speed and angle are effectively controlled by the deceleration buffering device and the rotation limiting device of the slewing mechanism.

08 Mar 2013
TL;DR: In this paper, the rolling elements are replaced by truss elements with a material non-linear characteristic located between the raceway centres of the curvatures in their axial section.
Abstract: In slewing bearings, a great number of contact pairs are present on the contact surfaces between the rolling elements and raceways of the bearing. Computations to determine the load of the individual rolling elements, taking into account the flexibility of the bearing ring, are most often carried out using the finite element method. Construction of a FEM full model of the bearing, taking into account the shape of the rolling elements and the determination of the contact problem for every rolling element, leads to a singularity of stiffness matrix, which in turn makes the problem impossible to solve. In FEM models the rolling elements are replaced by one-dimensional finite elements (linear elements) to simplify the computation procedure and to obtain an optimal time for computations. replaced by truss elements with a material non-linear characteristic located between the raceway centres of the curvatures in their axial section, are presented in the paper

Proceedings Article
15 Mar 2013
TL;DR: In this paper, the authors presented a numerical calculation procedure for determination of subsurface crack propagation in a large slewing ball bearing, where the Hertzian contact theory was used to obtain the amaximum contact force on the bearing raceway.
Abstract: This paper presents a numerical calculation procedure for determinationof subsurface crack propagation in a large slewing ball bearing. In the first step, amaximum contact force on the bearing raceway is obtained by means of analyticalexpressions, where the Hertzian contact theory is used. In the second step a 3D finiteelement model of the raceway segment and the contact load is simulated, and thesubsurface stresses and strains are obtained. At the time being the contact load on theraceway is approximated by Hertzian pressure distribution as calculated in theprevious step. Depth dependent elasto-plastic material properties are used in the finiteelement model of the raceway. In the third step a submodel with the elliptical crack ismade and the crack intensity factors are calculated. The linear elastic fracturemechanics theory is used for this purpose. Due to complexity of a problem at this verymoment the finite element analysis does not provide sufficient results. However, itseams that in near future an improved and fine-tuned finite element model will besuitable for characterization of subsurface crack propagation analysis.

Patent
17 Jul 2013
TL;DR: In this paper, a numerically controlled grinder for slewing bearing processing is presented, which includes a grinder body and a workbench, a column and a grind head assembly, a grinding wheel dresser, a numerical control system and cooling system.
Abstract: A numerically controlled grinder special for slewing bearing processing comprising a grinder body and a workbench, a column and a grind head assembly, a grinding wheel dresser, a numerical control system and a cooling system. The grinder body and the workbench comprise working turntable components including a working turntable seat, a working turntable and a turntable motor. The working turntable components are mounted on an X-axis rail of the grinder body and moves on the X-axis left to right driven by an X-axis servo motor and a ball screw mounted inside the grinder body to complete grind feed processing of the X-axis. A workpiece mounted on the working turntable is driven by the turntable motor to rotate with the turntable to complete rotate feed processing. The grind head assembly comprises a grind head motor, a grind head component is composed of a rotary grind head seat and a grind head grinding wheel; and the grind head motor is mounted on the rotary grind head seat, and the grind head grinding wheel is driven by a main shaft of the rotary grind head seat to rotate so as to complete grind processing. The surface of the grinding wheel can be trimmed to be in a shape of slewing bearing rolling grooves by the grinding wheel dresser. By the aid of the numerically controlled grinder, the inner and outer cycle faces, the rolling grooves and a mounting plane of the slewing bearing can be clamped and grind processed in one step synchronously.

Journal ArticleDOI
TL;DR: In this paper, a new approach for the design of the slewing bearing in super large lifting equipment is presented, which considers three kinds of sliding-friction models between the bearing structure and orbit.
Abstract: The slewing bearing of the full-revolving super large lifting equipment bears all loads above the rotating platform. Due to the effect of bending moment, the load conditions of the slewing bearing structure is complex and large, which leads to the non-uniform of stress and uneven deformation and final seriously affects the work performance of lifting equipment. The numerical example in this paper considers three kinds of sliding-friction models between slewing bearing structure and orbit. By numerical analysis results, we adjusted the structure arrangement and stiffness distribution. Finally the non-uniform of stress of the slewing bearing structure has been improved and tended to be uniform. Thus the paper presents a new approach for the design of the slewing bearing in super large lifting equipment.

Patent
24 Apr 2013
TL;DR: In this paper, a multidimensional dynamic stage with a stage, a swing frame, a first hydraulic cylinder and a second hydraulic cylinder is described, where a lifting frame which can be lifted is mounted in an inner chamber of the hollow frame, and a step is arranged on the lifting frame.
Abstract: The utility model discloses a multidimensional dynamic stage which comprises an outer hollow frame, a stage, a swing frame, a first hydraulic cylinder and a second hydraulic cylinder, wherein a lifting frame which can be lifted is mounted in an inner chamber of the hollow frame; a piston rod of the first hydraulic cylinder is connected with the lower end of the lifting frame; the swing frame is mounted below the stage and connected through a slewing bearing; a drive motor and a drive gear are mounted on the side surface of the swing frame; the drive gear is matched with the slewing bearing; a first lug seat is mounted on the upper end surface of the lifting frame; one end of the swing frame is connected with the lifting frame through the first lug seat; a step is arranged on the lifting frame; the second hydraulic cylinder is articulated to the step; and a piston rod of the second hydraulic cylinder is articulated with the other end of the swing frame. According to the multidimensional dynamic stage, lifting, tilting and rotating functions can be achieved through matching of the lifting frame, the swing frame and the slewing bearing according to plot needs, striking and exciting feelings are brought to audience, and performance scenes are rich and colorful.

Patent
20 Mar 2013
TL;DR: In this article, a crane slewing mechanism capable of adjusting a gap between gears is described, which is used to adjust a central distance between the drive gear and the outer gear ring of the slewing bearing.
Abstract: The invention discloses a crane slewing mechanism capable of adjusting a gap between gears. The crane slewing mechanism comprises a motor, a reducer and a slewing bearing fixed on a base, wherein an output end of the motor is connected with the reducer, the reducer is detachably arranged on a base seat through a flange, an output shaft of the reducer is fixedly connected with a gear which is meshed with an outer gear ring of the slewing bearing, and the gear and the flange are in a eccentric structure. The crane slewing mechanism capable of adjusting the gaps between the gears is simple in structure and easy to realize. Due to the fact that the gear and the flange are in the eccentric structure, when a central distance needs adjusting, the meshing gap between the drive gear and the outer gear ring of the slewing bearing can be changed as long as the flange is rotated, and therefore the meshing gap can be adjusted conveniently.

Patent
10 Apr 2013
TL;DR: In this paper, the authors proposed a utility model for an orbit-changed walking car of hoisting equipment, where wheels are arranged in the middle of the bottom end of the frame, in positions near both ends.
Abstract: The utility model relates to an orbit-changed walking car of hoisting equipment The walking car comprises a frame, wherein wheels are arranged in the middle of the bottom end of the frame, in positions near both ends; a plurality of lifting oil cylinders are also arranged at the middle of the bottom end of the frame; a slewing bearing is arranged at the middle of the top end of the frame; the top end of the slewing bearing is connected with the bottom end of the hoisting equipment; a support baffle plate arranged on the hoisting equipment is connected with one side of the slewing bearing through steering oil cylinders arranged horizontally The orbit-changed walking car provided by the utility model has the beneficial effects as follows: the working range of the hoisting equipment in orbit running is enlarged; the working efficiency is improved; the operating requirement of engineering machinery is met; the investment cost of the equipment is lowered, and the energy conservation and the consumption reduction are realized

Patent
10 Jul 2013
TL;DR: In this article, a crawler belt self-walking type lifting platform truck is applied to environments with bad road conditions, which is used in the utility model of self-walkers.
Abstract: The utility model provides a crawler belt self-walking type lifting platform truck which is applied to environments with bad road conditions The technical scheme is that the crawler belt self-walking type lifting platform truck comprises a crawler belt walking mechanism and an installation under frame which is arranged on the crawler belt walking mechanism through a slewing bearing A lifting platform is arranged on the installation under frame

Patent
16 Jan 2013
TL;DR: In this article, the utility model provides automatic rubber trimming equipment, which comprises a plurality of cutting tools and fixtures, a rotating working table, a fixture rotating system and a cutting tool regulation system.
Abstract: The utility model provides automatic rubber trimming equipment, which comprises a plurality of cutting tools, a plurality of fixtures, a rotating working table, a fixture rotating system and a cutting tool regulation system. The rotating working table comprises a bottom support, slewing bearings, a working tabletop, a servo motor and a torque increaser, wherein the slewing bearings are arranged on the bottom support; the working tabletop is arranged on the slewing bearings; and the servo motor and the torque increaser are arranged on the bottom support. The fixture rotating system is arranged on the working tabletop. The cutting tool regulation system is arranged on the bottom support. The automatic rubber trimming equipment is compact and simple in structure, and occupies a small space, potential safety hazards are reduced, environmental pollutions are reduced, production efficiency and quality are improved, and in addition, production cost is lowered.

Patent
12 Jun 2013
TL;DR: The container spreader for general purpose gantry cranes provided by the utility model has the advantages that a container is prevented from inclining, imbalance and shaking in use, the container is automatically rotated, and the handling efficiency of the container was improved.
Abstract: The utility model discloses a container spreader for general purpose gantry cranes. The container spreader comprises a lifting ring, a hoist rope and a twist lock mechanism anti-swing steel wire rope, a torque motor, an upper frame, a slewing bearing, a lower frame, a slewing motor, a slewing motor reducer, a twist lock driving motor and a twist lock driving motor reducer, wherein the upper frame is provided with a pin shaft and a connecting ring, and the pin shaft is connected with the hoist rope; the two ends of the anti-swing steel wire rope are respectively connected with the connecting ring and the torque motor, and the output end of the slewing motor reducer is connected with a small gear; the lower frame is of an X-shaped structure, and the twist lock driving motor and the twist lock driving motor reducer are installed on the lower frame; and the slewing bearing is connected with the upper frame and the lower frame and is meshed with the small gear, and the output end of the twist lock driving motor reducer is connected with a pull rod of a twist lock mechanism through a crank shaft. The container spreader for the general purpose gantry cranes provided by the utility model has the advantages that a container is prevented from inclining, imbalance and shaking in use, the container is automatically rotated, and the handling efficiency of the container is improved.

03 May 2013
TL;DR: In this paper, a non-standard approach has been used to calculate the fatigue life of large slewing bearings. But the method is not suitable for wind turbines, as it is unsuitable for wind turbine blade flange bearings.
Abstract: Large slewing bearings are designed to sustain axial, radial and tilting moments Due to their design and manufacturing process, a nonstandard approach has to be used to calculate the fatigue life First, a maximum contact force is obtained from the load distribution in a bearing by means of analytical expressions of the Hertzian contact theory Then, a strain-life approach is used to calculate the fatigue life on the basis of the subsurface stresses as obtained from the finite element analysis Experimentally determined depth-dependent elasto-plastic material properties, which appear as a result of hardening, are taken into consideration The fatigue life largely depends on external bearing loads For an external loading, which results in 3200 MPa contact pressure on a bearing raceway, the fatigue life is approximately 469e7 load cycles (154e6 revolutions) The calculated fatigue life is in accordance with the requirements of the fatigue life of wind turbines’ blade flange bearings

Patent
31 Jul 2013
TL;DR: In this article, a planetary gear case for a vertical shaft stirring machine is characterized, where an output shaft is provided with a sleeve I used for fixing the output shaft onto the gear case.
Abstract: The utility model discloses a planetary gear case for a vertical shaft stirring machine. The planetary gear case for the vertical shaft stirring machine comprises a motor, a gear, an input gear shaft, a primary reduction gear shaft, secondary reduction gear shafts, a high-speed shaft and a slewing bearing. The planetary gear case for the vertical shaft stirring machine is characterized in that an output shaft is provided with a sleeve I used for fixing the output shaft onto the gear case; the gear is axially fixed by the upper end of the output shaft through a gasket; both ends of inner and outer rings of an upper bearing of the output shaft are fixed by a washer, a bearing block, the sleeve I and a shaft shoulder; a lower bearing of the output shaft is fixedly arranged in the bearing block by a bearing cap and a sleeve II; the outer ring of the lower bearing can float without a flange; moreover, sealing elements are respectively and additionally arranged at mutual matching positions of the bearing cap and a shaft and the sleeves and the shaft; and the slewing bearing is additionally provided with a cover plate provided with the sealing elements. Through improving the structure of the planetary gear case for the vertical shaft stirring machine, the integral disassembling of a high-speed gear shaft is realized, the service life of the output shaft is prolonged, the oil leakage problem of a traditional sealing structure is solved, and the safe reliability of the gear case is enhanced.


Patent
23 Oct 2013
TL;DR: In this article, the utility model provides a welding device for welding vertical circular seams of a pressure vessel, which is suitable for welding large and super-large pressure vessels, is high in welding quality and work efficiency, and can lower production labor cost.
Abstract: The utility model provides a welding device for welding vertical circular seams of a pressure vessel. The welding device comprises a base, a jack, a slewing device, a positioning device, a pressure vessel protecting device, a welding gun clamping device, a welding gun and a control cabinet. The jack is arranged on the side portion of the bottom of the base, the slewing device comprises a slewing platform, a slewing bearing, a slewing bottom frame and a gear motor. The gear motor can drive the slewing platform to stably rotate at a low speed under a load bearing condition. The positioning device is fixedly mounted at the center of the slewing platform. The pressure vessel protecting device comprises a bracket support and a rolling device. The welding gun clamping device is arranged beside the slewing device and provided with a welding gun cross-shaped adjusting frame, and the welding gun is fixedly mounted on the welding gun cross-shaped adjusting frame. The control cabinet is arranged beside the base and connected with the gear motor and the welding gun through wires. Mechanical automatic welding operation is used in the welding device, and the welding device is suitable for welding large and super-large pressure vessels, is high in welding quality and work efficiency, and can lower production labor cost.

Patent
02 Oct 2013
TL;DR: In this article, an L-shaped welding positioner consisting of a rack, a turnover mechanism, and a slewing mechanism arranged on the turnover mechanism is presented. But the positioner is not suitable for welding.
Abstract: The invention discloses an L-shaped welding positioner which comprises a rack, a turnover mechanism arranged on the rack, and a slewing mechanism arranged on the turnover mechanism. The rack consists of a base and a box body arranged on the base; the turnover mechanism is connected with a rotating gear by a rotary motor speed reducer; the rotating gear is meshed with a rotating bearing; an outer ring of the rotating bearing is provided with a rotating arm; an inner ring of the rotating bearing is fixedly connected with the box body; the slewing mechanism is connected with a turning gear by a rotation motor speed reducer arranged in a revolving arm; the turning gear is meshed with a slewing bearing; an outer ring of the slewing bearing is provided with a disk; and an inner ring of the slewing bearing is fixedly connected with the revolving arm. The invention provides the L-shaped welding positioner which has high operation accuracy, stability for operation, low energy consumption and low noise and is convenient to install and use.

Patent
27 Nov 2013
TL;DR: In this paper, a special gauge for detecting an inner raceway of a slewing bearing is presented. But the detection precision is poor and the detection efficiency is low during the detection and measurement process of the inner racing track of the bearing.
Abstract: The utility model discloses a special gauge for detecting an inner raceway of a slewing bearing The special gauge is characterized by comprising dial gauge body (6) and a measuring head (61) thereof, and the gauge further comprises a fixed measuring rod (2) and an adjustable measuring rod (4), wherein one end of the fixed measuring rod (2) is connected with the adjustable measuring rod (4) in a telescopic adjustable manner through a tightening nut (3), the end head of an opposite end is provided with a standard ball head (1), one end of the adjustable measuring rod (4) is provided with the dial gauge body (6), one end of the dial gauge body (6) is provided with a connecting rod (62), the opposite end is provided with a measuring head (61), the dial gauge body (6) is fixedly connected with the adjustable measuring rod (4) through the connecting rod (62) and a fastening bolt (5), and the measuring head (61) and the standard ball head (1) are positioned on the same horizontal axis The special gauge effectively solves the problems in the prior art that auxiliary tools are needed for indirect measurement, the detection precision is poor and the detection efficiency is low during the detection and measurement process of the inner raceway of the slewing bearing

Journal ArticleDOI
TL;DR: In this paper, an elastic constitutive model is used in the 3D finite element analysis of load deformation characteristic of large diameter bearing ball -raceway contact and the finite element results are validated by conducting experiment on the linear mock up model bearing.
Abstract: The objective of the present study is to obtain relevant contact stiffness for a single ball-raceway contact which can be used in load distribution analysis of full bearing. Towards this, an elastic constitutive model is used in the 3D finite element analysis of load deformation characteristic of large diameter bearing ball - raceway contact and the finite element results are validated by conducting experiment on the linear mock up model bearing. The FE results show a good agreement with the values calculated using Hertz’s relations for deformation. Key words: Fast breeder reactor, rotatable plugs, slewing bearing, load-deformation, finite element analysis, rolling element, bearings, experimental analysis.

Patent
27 Mar 2013
TL;DR: In this article, a gap detection device of a large slewing bearing is presented, which consists of a radial error detection table, three groups of symmetrically-distributed axial error detection tables, a detection working table frame with a spiral pressing plate clamping mechanism, a Slewing bearing to be detected, a controller and a displayer.
Abstract: The invention provides a gap detection device of a large slewing bearing and belongs to the technical field of industrial measurement. The gap detection device comprises a radial error detection table, three groups of symmetrically-distributed axial error detection tables, a detection working table frame with a spiral pressing plate clamping mechanism, a slewing bearing to be detected, a controller and a displayer. Each axial error detection table comprises an axial servo motor, an axial rolling guide rail, an axial ball screw, a centering mechanism, an axial screw nut, an axial servo electric pushing rod, an axial working table plate, an axial base and an axial displacement sensor. The radial error detection table comprises a radial servo motor, a locking mechanism, a radial ball screw, a radial rolling guide rail, a radial screw nut, a radial working table plate, a radial servo electric pushing rod, a fork head, a radial base and a radial displacement sensor. The gap detection device of the large slewing bearing has the advantages of being high in detection accuracy, convenient to operate and high in detection efficiency.