Showing papers on "Slewing bearing published in 2014"

Computational Analysis of Contact Stress Distribution in the Case of Mutual Slewing of Roller Bearing Rings

Abstract: The paper deals with computational analysis of contact stress distribution of rolling elements of roller bearing with regards to the effect of slewing bearing ring at intervals from 0 to 8 and load rate variety at intervals from 25% to 100% of its basic static radial load capacity. The main goal is to present changes in contact ellipse and changes in contact stress for the logarithmic profile of rolling element. Analyzed effect is expressed by functional dependence which can be used in technical application.

Technology and experiments of 42CrMo bearing ring forming based on casting ring blank

Abstract: Bearing ring is the crucial component of bearing. With regard to such problems as material waste, low efficiency and high energy consumption in current process of producing large bearing ring, a new process named “casting-rolling compound forming technology” is researched by taking the typical 42CrMo slew bearing as object. Through theoretical analysis, the design criteria of the main casting-rolling forming parameters are put forward at first. Then the constitutive relationship model of as-cast 42CrMo steel and its mathematical model of dynamic recrystallization are obtained according to the results of the hot compression experiment. By a coupled thermal-mechanical finite element model for radial-axial rolling of bearing ring, the fraction of dynamic recrystallization is calculated and recrystallized grains size are predicated. Meanwhile, the effects of the initial rolling temperature and feed rate of idle roll on material microstructure evolution are analyzed. Finally, the industrial rolling experiment is designed and performed, based on the simulation results. In addition, mechanical and metallographic tests are conducted on rolled bearing ring to get the mechanical parameters and metallographic structure. The experimental data and results show that the mechanical properties of bearing ring produced by casting-rolling compound forming technology are up to industrial standard, and a qualified bearing ring can be successfully formed by employing this new technology. Through the study, a process of forming large bearing ring directly by using casting ring blank is obtained, which could provide an effective theoretical guidance for manufacturing large ring parts. It also has an edge in saving material, lowering energy and improving efficiency.

Degradation Trend Estimation and Prognosis of Large Low Speed Slewing Bearing Lifetime

Abstract: In many applications, degradation of bearing conditions is usually monitored by changes in time-domain features. However, in low speed (< 10 rpm) slewing bearing, these changes are not easily detected because of the low energy and low frequency of the vibration. To overcome this problem, a combined low pass filter (LPF) and adaptive line enhancer (ALE) signal pre-conditioning method is used. Time-domain features such as root mean square (RMS), skewness and kurtosis are extracted from the output signal of the combined LPF and ALE method. The extracted features show accurate information about the incipient of fault as compared to extracted features from the original vibration signal. This information then triggers the prognostic algorithm to predict the remaining lifetime of the bearing. The algorithm used to determine the trend of the non-stationary data is auto-regressive integrated moving average (ARIMA).

High-rise building outer wall cleaning vehicle

Abstract: The utility model relates to a high-rise building outer wall cleaning vehicle. The high-rise building outer wall cleaning vehicle comprises a hatchback, a suspension arm, an auxiliary suspension arm, a control chamber, a water storage tank, an alkali liquor tank, an alkali and water mixing tank, a centrifugal pump, a manifold, a parallelogram four-bar linkage, a motor, a limiting base plate, a cross-shaped guide rail rack, a disk type wall scrubber, a guide column, a buffer spring and the like. The hatchback is not different from hatchbacks of other automobile cranes, a chassis is arranged in the rear of the hatchback, and a rotary platform and the chassis are connected through a slewing bearing capable of bearing vertical loads, horizontal loads and upsetting moment. A rotary platform locking device is arranged in order to prevent the rotary platform from slipping in the driving process, a swing mechanism is driven by a constant displacement motor, and an output gear is meshed with a slewing bearing gear. The high-rise building outer wall cleaning vehicle is safe, high in efficiency, intelligent and economical. Many cleaners are liberated from high-rise operation, the working mode of the high-rise building outer wall cleaning vehicle is mechanized and intelligent, and the high-rise building outer wall cleaning vehicle is very high in working efficiency. Meanwhile, consumption of water and cleaning liquid is greatly reduced in operation.

Slewing bearing quenching type inner gear ring processing technology

Abstract: The invention relates to a slewing bearing quenching type inner gear ring processing technology The technology processes comprise workblank roll forming, rough turning, half finish turning, rolling path quenching, finish turning I, gear producing, gear tooth quenching, finish turning II, finish turning III, rolling path polishing and mounting hole drilling The processing technology is characterized in that the stage of the finish turning III comprises the following steps: placing the bottom surface of a workpiece on a contour cushion of a worktable, rectifying through an excircle positioned at the lower part of a rolling path, performing finish turning on the end surface and the excircle positioned at the upper part of the rolling path, and processing the size H, and the size D of the excircle positioned at the upper part of the rolling path to the size required by a drawing Through the adoption of the technology, the content of the finish turning III process is enlarged after a gear tooth is quenched, the parallelism requirement of the bottom surface (the standard plane) of the workpiece and the end surface (a non-standard plane) of the workpiece are ensured, and reliable processing standard guarantee can be provided for the follow processes, so that the precision of slewing bearing is improved, the mounting and application of the slewing bearing product can be ensured, and then the service life of the slewing bearing product and a connecting bolt can be prolonged

Analysis of Influence of Bearing Clearance on the Static Carrying Capacity of Multi-row Slewing bearings

Abstract: The effect of selected bearing clearances in double row ball bearing and three row roller on their static carrying capacity is presented in the paper. An original method of determination of these profiles by means of the author's program that was based on a calculation model with rigid rings was proposed. This program allows on automated preparation of static load carrying capacity profile for the different defined values of clearance bearing. This consideration is illustrated by an example that was carried out for bearing in nominal state i.e. bearings without clearance and for acceptable value of bearings clearances that was defined by producer. Some specific points of bearing's operation and the distribution of internal load for these areas were also discussed. A mechanism of formation this load distribution on individual rolling elements of bearing was discussed. The detailed description of the course of the carrying capacity characteristics with repeated appearing of the local minimum was made.

Automatic green brick stacking machine

Abstract: The utility model discloses an automatic green brick stacking machine. The automatic green brick stacking machine is provided with a portal frame, the portal frame is provided with a sliding lifting mechanism which is composed of a sliding platform and a lifting platform, a plurality of sets of green brick jigs are arranged below the lifting platform, the green brick jigs are installed on a base, a slewing mechanism is arranged between the base and the lifting platform, and the slewing mechanism comprises a slewing bearing and an air cylinder, wherein the slewing bearing is hung below the lifting platform through a connecting sleeve, and the air cylinder is arranged between the slewing bearing and the base. The base is hung by the slewing bearing, and the base can be driven by the air cylinder to horizontally rotate. The slewing bearing is provided with a speed reducing buffering device and a rotation limiting device in a matched mode. The slewing mechanism is driven by the air cylinder, the transmission interval is eliminated, and rotation precision is improved. The rotation speed and the rotation angle can be controlled well through the speed reducing buffering device and the rotation limiting device of the slewing mechanism.

Smart health evaluation of slewing bearing based on multiple-characteristic parameters

Abstract: A rotational connection between two substructures generally consists of a slewing bearing which is very often used for heavy loads at low speeds. Slewing bearing condition monitoring is a good method to identify the inception and propagation of structural defects at an early stage for timely remedy, and ultimately, enable condition-based “intelligent” maintenance instead of schedule-based. The traditional health evaluation accuracy is not high based on single vibrating signal. We present a new strategy for health evaluation of slewing bearing based on multiple characteristic parameters and the artificial neural networks, and we applied the genetic algorithm to model multiparameters health evaluation. Seventy days fatigue life test was carried out using a special slewing bearing test table and 70 sets data was chosen to input the networks evaluation model for training and evaluation. Test results show that the ANN (Artificial neural network) with GA (Genetic algorithm) optimization converges more easily, takes fewer iterations and shorter training time, and has higher precision and good stability. And the output of multi-parameters health evaluation network model shows a better agreement with the target. The evaluation results were in accordance with the experiment. Therefore, this methodology can be used to evaluate the health state of slewing bearing.

Roof surface crane for building

Abstract: The invention relates to a roof surface crane for a building. The roof surface crane includes a lower slewing bearing, a boom, a central vertical frame and a winding engine; the lower slewing bearing is fixedly mounted on a roof of the building; the central vertical frame is vertically fixed on the center of the lower slewing bearing; the winding engine is mounted on the lower slewing bearing; the tail of the boom is hinged to the lower slewing bearing, and the head of the boom is connected with a hook by a main steel rope; the main steel rope passes through a pulley of the head of the boom and then is connected with the winding engine; the head of the boom is connected with the head of the central vertical frame through a luffing steel wire rope; the head of the central vertical frame is provided with two supporting rods in a hinged mode; the supporting rods are hinged with the roof. With utilization of the roof surface crane, a balancing weight block, upper structures and the like of an internally-climbing tower type hoist are lifted to the roof, and then are lifted to the ground from the roof one by one after being respectively disassembled into smallest units, so that the internally-climbing tower type hoist is dismantled.

Heavy vehicle tire changer

Abstract: The utility model provides a heavy vehicle tire changer which comprises a hydraulic device, an electric control device and a mechanical device, wherein the mechanical device comprises a tire clamping jaw, a spindle pulley and a rotating reducer; the rotating reducer comprises a slewing bearing, a worm and a base; the slewing bearing is fixedly connected with the tire clamping jaw; the base is fixedly connected with the spindle pulley; the worm is connected with the hydraulic device; and the hydraulic device provides driving power for the rotating reducer. The heavy vehicle tire changer provided by the utility model is simple and convenient in overall installation and convenient to maintain and is suitable for being used in dismounting operation of tires of which the weight exceeds over 2.5 tons.

Slewing bearing device for live tree transplanting tree mover

Abstract: The invention discloses a slewing bearing device for a live tree transplanting tree mover. The slewing bearing device comprises an arc movable sliding rail and an arc fixed sliding rail. An arc groove is formed in the arc lower end face of the fixed sliding rail, the upper portion of the movable sliding rail is embedded in the arc groove and is in sliding fit with the fixed pulley, and a gear ring is arranged on the arc inner wall of the movable sliding rail. A motor is installed on the fixed sliding rail, and an output gear of the motor is in meshing transmission with the gear ring on the movable sliding rail. The slewing bearing device comprises an n-shaped support of the tree mover, two ends of the n-shaped support are hinged to two sides of the upper end of the fixed sliding rail through suspension supports, and an angle adjusting oil cylinder is connected between the n-shaped support and the fixed pulley. A beam is installed at the bottom of the movable sliding rail, and a tree moving cutter is installed on the beam. The slewing bearing device achieves innovation of the mechanical operation mode and a manufacture technology, pushes great technical progress of the novel live tree transplanting tree mover from product concept research and development to novel product appearing, and improves big tree transplanting production mechanical operation efficiency. The mechanical operation efficiency is improved by 20-30 times compared with manual operation.

Cantilever bin discharger

Abstract: The utility model provides a cantilever bin discharger, comprising a slewing bearing and a spiral output shaft, wherein the slewing bearing is arranged at a discharging opening at the center of the bottom of a bin and is provided with a conical-top shield; a horizontal sprocket shaft is arranged on a rotary plate of the slewing bearing through a sprocket shaft frame and is provided with a driven sprocket, a motor is arranged below the slewing bearing, a shaft of the motor is directly connected with a speed reducer, the speed reducer is fixedly arranged on the lower surface of the rotary plate of the slewing bearing, the output shaft of the speed reducer is provided with a driving sprocket, and the driving sprocket is connected with the driven sprocket through a chain; the spiral output shaft is connected with the sprocket shaft in a coaxial line; a hydraulic slewing transmission device is fixedly arranged on the base of the discharging opening at the center of the bottom of the bin, and a gear on the output shaft of the hydraulic slewing transmission device is meshed with a gear ring of the slewing bearing; a discharging cylinder is connected with the lower part of the rotary plate of the slewing bearing, and a material containing funnel is arranged at the lower end of the discharging cylinder; an electric slip ring is fixedly arranged at the center of the material containing funnel. The cantilever bin discharger disclosed by the utility model has the advantages that the structure is simple, and the device cost, the configuration cost, the accident rate and the maintenance cost are low.

Influence of groove shape on clearance in four-point-contact slewing bearing

Abstract: Starting friction torque is a very important characteristic for some applications and clearance influences the starting friction torque directly for those slewing bearings with negative clearance. The relationship between groove shape and clearance variation is established in the paper and two experiments are designed to verify the correctness of theoretic analysis. A new processing technology for final processing of groove in four-point-contact slewing bearings is suggested according to theoretic analysis and experiment research in the paper.

Fault diagnosis of wind power yawing slewing bearing based on support vector machine

Abstract: A fault diagnosis method based on wavelet energy spectrum and support vector machine( SVM) was proposed in terms of less fault samples,weakness of signals and difficulty to be extracted of wind power slewing bearing. Feature vectors were constructed by combining wavelet energy spectrum of acceleration signal with temperature and torque signal. And three normal states: single bolt fracture and multiple bolt fracture were classified by using SVM with classification accuracy of 100%,while the classification accuracies for the same samples reached only 84%,92%,and 80%,respectively by the BP neural network method. Results show that SVM method is more suitable than BP neural network method for wind power slewing bearing fault diagnosis.

Hoisting crane and method for refurbishing such a hoisting crane

Abstract: Hoisting crane (1) comprising a slew bearing (7). The slew bearing comprises a top bearing ring (9), a bottom bearing ring (10), a first row of axial load rollers (11) and a second row of axial load rollers (12), which rows of axial load rollers are provided between a corresponding top roller raceway (13, 14) and bottom roller raceway (14, 15). According to the invention, the top bearing ring has a top wall which extends above the first row of axial load rollers and in which at least one top entry port (18) is provided. Furthermore, the top roller raceway of the first row of axial load rollers comprises a removable raceway segment (19) releasable attached in the top entry port. The removable raceway segment can be removed to enable access via the top entry port to the first row of axial load rollers to remove axial load rollers in a substantially vertical direction.

Experimental determination of bearing loads in rotating platform drive mechanisms of hydraulic excavators

Abstract: The paper presents a procedure for experimental determination of slewing bearing loads in the rotating platform drive mechanisms of hydraulic excavators with an excavating manipulator. A mathematical model is defined which enables the determination of the vectors of force and moment of bearing loads, on the basis of the measured quantities of the state of an excavator in operation under exploitation conditions. The measured quantities of the state of an excavator relate to the position of the kinematic chain and pressures of the hydrostatic system in the actuator ducts of the excavator drive mechanisms. As an example, the paper provides the research results obtained in the experimental determination of slewing bearing loads in the rotating platform drive mechanism of a hydraulic excavator with the mass of 16t.

Column type hopper mixer

Abstract: The invention discloses a column type hopper mixer which comprises a bottom plate; the bottom plate is provided with a hydraulic tank and a stand column; the top of the stand column is provided with a top support; a tackle component is arranged in the stand column; the tackle component is connected with a lifting oil cylinder and a transmission box; the transmission box is connected with a mixing hopper by a fork rack; the transmission box comprises a transmission box body which is provided with a housing; the transmission box body is internally provided with a speed reducing motor which is connected with a pinion; the pinion is connected with a slewing bearing; the slewing bearing is connected with the fork rack. The column type hopper has the advantages of being stable in transmission and heavy in load.

Vehicle-mounted screw ship unloader

Abstract: The utility model relates to a vehicle-mounted screw ship unloader comprising a vehicle chassis, a slewing bearing platform and a foldable screw conveying mechanism. The slewing bearing platform is mounted on the vehicle chassis through an internal teeth type slewing bearing, and driven by a hydraulic slewing device. An 'inverted-L'-shaped column is mounted at one end of the slewing bearing platform, a power and control system is mounted at the other end of the slewing bearing platform, the lower end face in the horizontal end face of the 'inverted-L'-shaped column is hinged to a connecting mechanism through a first toothless slewing bearing, and a hinge axis of the connecting mechanism is coaxial with a slewing axis of the slewing bearing platform. The foldable screw conveying mechanism comprises a lower screw conveyor, a middle screw conveyor, an upper screw conveyor and a loading screw conveyor. When the complete vehicle moves on a road, each screw conveyor is in a folding state, when the vehicle reaches a working site, the screw conveyors can quickly unfold to be putted into operation, and the vehicle-mounted screw ship unloader has the advantages of high mobility of the complete vehicle, high efficiency and the like.

Cooling arrangement for a propulsion unit

Abstract: A propulsion unit is disclosed with a hollow strut having an upper portion with an upper end portion passing through a passage (P 1 ) formed between a first outer bottom and a second inner bottom in a vessel. The upper end portion is rotatably supported with a slewing bearing and sealed with a slewing seal towards the vessel. A cooling arrangement includes a cooling air duct system, at least one fan and at least one cooling unit. The slewing seal can include an upper slewing seal and a lower slewing seal at a vertical distance (H 1 ) from each other with a space formed between the slewing seals. The upper end portion has openings (O 1 ) into the space between the slewing seals. A first cooling air duct is directed to this space, whereby cooling air (L 1 ) can be circulated through the first cooling air duct ( 400 ) into the space and through the openings (O 1 ) in the upper end portion to the interior of the strut, or return air (L 2 ) can be circulated from the strut in an opposite direction.

Effects of Bearing Characteristic on the Gear Load Distribution in the Slewing Reducer for Excavator

Abstract: A slewing reducer consists of two planetary gearsets which require a good load distribution over the gear tooth flank for enhanced durability. This work investigates how the bearing characteristics influence the load distribution over the gear tooth flank. A complete system model is developed to analyze a slewing reducer, including the non-linear mesh stiffness of the gears and the non-linear stiffness of bearings. The results indicate that the type, arrangement and preload of the output shaft bearings greatly influence the gear mesh misalignment, contact pattern, face load factor, gear safety factor and lifetimes of the parts.

Semi-submersible platform with floating body direction adjustable and adjusting method

Abstract: The invention discloses a semi-submersible platform with a floating body direction adjustable and an adjusting method. The semi-submersible platform is sequentially composed of a platform body, four uprights, four slewing bearings and four fish-shaped floating bodies from top to bottom, and the platform body, the uprights, the slewing bearings and the fish-shaped floating bodies are connected in sequence. The semi-submersible platform further comprises an anchor mooring positioning system and a direction adjusting device which are arranged on the platform body. The adjusting method includes that seawater flow speed and flow direction signals of the same can be detected through a flow speed and flow direction sensor, included-angle signals of length wise direction of the fish-shaped floating body and the platform body can be measured through an angle measurement sensor and transmitted to an industrial personal computer, and the industrial personal computer transmits a control instruction to a rotary servo motor to drive the slewing bearings, so that the fish-shaped floating bodies are enabled to correspondingly rotate to the respective uprights till the length wise direction of the fish-shaped floating body is parallel to the seawater acting direction. Therefore, the probability that an anchor is pulled out of a seabed is minimized, and normal operation of the semi-submersible platform is beneficially ensured.

Novel amusement excavator

Abstract: The utility model relates to a novel amusement excavator The novel amusement excavator is used for solving the problems of the existing amusement excavators that the size of a slewing bearing is large, the cost is high and the assembly and repair are difficult Thus, the novel amusement excavator comprises a scraper bucket, a front scraper arm, a rear scraper arm and a slewing platform, wherein the slewing platform comprises an upper underpan and a lower underpan, a fixed gear disc or fixed worm gear is arranged at the middle part of the lower underpan, a bearing seat hole is formed in the center of the fixed gear disc or fixed worm gear, a tapered roller bearing is arranged in the bearing seat hole, a rotary hollow shaft is arranged in the center of the tapered roller bearing in a penetrating manner, a ring flange is arranged at the top of the rotary hollow shaft, and the rotary hollow shaft is driven by a rotation driving mechanism The novel amusement excavator is low in production cost and convenient in repair and assembly and is applicable to the mounting use of multiple indoor and outdoor playgrounds

Fault Diagnosis Method of Mini Excavator Slewing Bearing

Abstract: In order to collect the fault signal of slewing bearing, design and built up the slewing bearing test rig and the signal test system. Because slewing bearing fault signal is weak, the signal containing fault characteristics was resolved and reconstructed with the wavelet theory. With the application of the Hilbert transform in demodulation and detailed spectrum analysis, the fault characteristic frequency was extracted, and the slewing bearing fault was judged. All above work shows that Wavelet analysis combined with the Hilbert analysis is effective to the diagnosis of rotary bearing local fault.

Three-layer longitudinally-moving rotary lifting parking garage

Abstract: The utility model provides a three-layer longitudinally-moving rotary lifting parking garage. A #-shaped frame is formed by splicing four H-shaped steel stand columns. One beam guide rail is connected between the top portion of the left stand column and the top portion of the right stand column, and the other beam guide rail is connected between the middle portion of the left stand column and the middle portion of the right stand column. Two longitudinally-moving frames are arranged on the beam guide rails through guide rail wheels on the two sides of the two longitudinally-moving frames, and a longitudinally-moving motor is connected with the longitudinally-moving frames through chains. The longitudinally-moving frames are provided with worm wheel slewing bearings, a rotary frame is provided with a slewing bearing plate to be fixedly connected with the worm wheel slewing bearings on the longitudinally-moving frames, the rotary frame is provided with a lifting motor, the lifting motor is connected with four steel rope pulleys on the two sides of the rotary frame through steel ropes in a winding-around mode, and the steel ropes on the steel rope pulleys are connected with steel rope connecting columns on the two sides of a lifting parking platform. The longitudinally-moving motor is started, the longitudinally-moving frames are driven to move forwards along the guide rail beams, and after the longitudinally-moving frames are moved to the tail ends of the guide rail beams, a rotating motor is started to drive the worm wheel slewing bearings to rotate, the worm wheel slewing bearings drive the rotary frame to rotate by 90 degrees, and the lifting motor is started and drives the parking lifting platform to descent to the ground.

Slewing bearing type bottle cap forming moulding press

Abstract: The invention relates to a slewing bearing type bottle cap forming moulding press. The slewing bearing type bottle cap forming moulding press comprises an extruding mechanism, a feeding mechanism, a bottle cap discharging mechanism, a main machine part assembly, a mold part and a transmission mechanism, wherein the transmission mechanism is driven by a motor, the extruding mechanism comprises a heating cylinder and a heating screw rod, a hopper is arranged on the heating cylinder, a discharge hole is formed in the head part of the heating cylinder and is matched with the feeding mechanism, the mold part comprises an upper mold and a lower mold, the main machine part assembly comprises a slewing bearing arranged in a rack, a transmission shaft is connected under the slewing bearing and is connected with the transmission mechanism, a support body is arranged on the slewing bearing, a connecting flange and a fuel distributor are arranged on the support body, a large tray lower plate is arranged on the fuel distributor, a rotating body is arranged on the large tray lower plate, a middle plate and a large tray upper plate are arranged on the rotating body, the upper mold is arranged on the middle plate, the lower mold is arranged on the large tray lower plate, and the bottle cap discharging mechanism is arranged on the large tray upper plate.