Ball Pin Research Articles

Development of technology and experience in the production of truck ball pins made of economically alloyed steel

Development of technology and experience in the production of truck ball pins made of economically alloyed steel

МЕХАНИЗМ ИЗНАШИВАНИЯ ПАР ТРЕНИЯ В ШАРНИРНЫХ СОЕДИНЕНИЯХ РУЛЕВЫХ ПРИВОДОВ АВТОМОБИЛЕЙ

Wear mechanism of friction pairs in the articulated joints of steering gears of UAZ-Hunter -315195 cars is considered. The wear process of friction pairs "bush (cup) – ball pin" closed with spherical spring washers and a spring cap used in the design of the swivel joint of the car steering gear is described. The effect of fretting corrosion on the destruction of a ball joint is studied.

Development of a Novel Ball-and-Socket Flexible Manipulator for Minimally Invasive Flexible Surgery

This work proposes a novel flexible manipulator consisting of a series of 2-DOF vertebrae based on a ball-andsocket joint that is connected by a ball-shaped surface and a cupshaped socket and constrained by pins for circumferential rotation. This manipulator can demonstrate outstanding torsional stiffness since the circumferential rotation between the vertebrae is constrained by four ball pins. The point contact between ball pins and guideways effectively reduces the friction between the vertebrae, thus allowing the designed manipulator to yield a smooth bending shape with constant curvature. This manipulator features high axial and torsional stiffness, excellent bending performance, sufficient loading capacity, and convenient integration with surgical instruments. Moreover, the excellent torsional stiffness enables this manipulator to efficiently transfer torque and be applied in in-situ torsional motion, effectively addressing the typical issue of limited dexterity for torsional motion. The kinematic modeling of the proposed manipulator under in-situ torsional motion has been derived, and its workspace has been analyzed. A robotic system has been assembled, and experiments have verified the proposed design and modeling validity. The results show that the maximum position errors in bending motion are 2.39% (horizontal direction) and 1.98% (vertical direction), and its torsional stiffness is 21.13N∙mm/deg, which is 46 times higher than that of a typical spherical flexible manipulator (SFM). Such merits support this manipulator excellently performing the in-situ torsional motion with a maximum average position error of 3.58%. Furthermore, a phantom test of the larynx has been performed to verify the potential of clinical feasibility.

Experimental Study of Material Structure in the Processing of Ball Pins

The article presents a technique for experimental studies of microstructure of microsections during rolling of ball pins made of 38KHGNM and 40KH steels. Moreover, photographing was carried out in the pole and equatorial parts of the ball pin head, as well as at the cross-cut end. When analyzing the photographs of microsections, it was concluded that after the final rotary rolling, deformation grinding of the grains occurred in the structure of ball pins.

Analysis of multiple failure behaviors of steering knuckle ball hinge of multi-axle heavy vehicle

The ball hinge is a key component of the vehicle chassis that connects the steering knuckle and the control arm. The study analyzed the multiple failure behaviors of the chassis ball hinge. Firstly, according to the macroscopic failure characteristics of the ball hinge, the fault tree analysis method was adopted to identify the possible cause of the failure. Then, the axial load and radial load on the ball joint were obtained by simulating the force of the vehicle under the typical extreme conditions. The stress distribution of the ball pin was obtained by finite element analysis of the ball joint. The calculation results are consistent with the fatigue crack position of the ball hinge. Finally, the macro morphology and microstructure of the ball joint seat, ball bowl, dust cover and other parts matched with the ball hinge were analyzed to further verify the failure mode of the ball hinge. The results showed that the dust cover of the ball hinge was firstly aged and cracked, and the external dust and particles enter into the friction contact area of the ball hinge, which caused the ball pin and ball bowl to be stuck. During the operating of the vehicle, the ball pin undergoes unidirectional bending fatigue fracture in the stress concentration area at the root of the conical surface.

Analysis of multiple failure behaviors of steering knuckle ball hinge of multi-axle heavy vehicle

The ball hinge is a key component of the vehicle chassis that connects the steering knuckle and the control arm. This study analyzed the multiple failure behaviors of the chassis ball hinge. First, according to the macroscopic failure characteristics of the ball hinge, the analysis method of the fault tree was adopted to identify the possible cause of the failure. The axial force and radial force of the ball joint were obtained by simulating the force of the vehicle under the typical extreme conditions. The stress distribution of the ball pin was obtained by finite element analysis of the ball joint. The calculation results are consistent with the fatigue crack position of the ball hinge. Then the ball hinge was disassembled. On the one hand, the macro morphology was observed. On the other hand, the chemical composition and microstructure of the ball pin material were analyzed by scanning electron microscope and infrared spectrum analyzer. Finally, the macro morphology and microstructure of the ball joint seat, ball bowl, dust cover and other parts matched with the ball hinge were analyzed to further verify the failure reason of the ball hinge. The results showed that the dust cover of the ball hinge was firstly aged and cracked, and the external dust and particles enter into the friction contact area of the ball hinge, which caused the ball pin and ball bowl to be stuck. During the driving process of the vehicle, the ball pin undergoes unidirectional bending fatigue fracture in the stress concentration area at the root of the conical surface.

New Abrasive Coatings: Abraded Volume Measurements in Ceramic Ball Production

Technological progress in hybrid bearings developed high wear and abrasion resistant materials for rolling elements. The manufacturing process of bearing balls presents new challenges, as nowadays, it requires time-consuming and costly processes. In this frame, the bearing manufacturing industry is demanding improvements in materials, geometry, and processes. This work aims to investigate new abrasive coatings for grinding wheels for Si3N4 ball manufacturing. Tribological pin on disk tests are performed on samples of grinding materials (disk) versus a Si3N4 ball (pin). Two samples of specimens coated with an electrodeposited diamond and diamond-reinforced metal matrix composite are examined to measure the abrasion rate and the wear resistance of Silicon Nitride Si3N4 balls, considering the influence of sliding speed and the effect of coating deposition on diamond particle density and granulometry. The measurements estimated the specific wear coefficient k, the height wear surface h, and the wear rate u of the Si3N4 balls. The results pointed out that by increasing the sliding speed, the abraded volume increases for both the coatings. The parameters affecting the abrasion effectiveness of both the coatings are the surface roughness, the abrasive particle dimension, and the sliding speed.

A Study on Wear and Friction of Passenger Vehicles Control Arm Ball Joints

The following paper describes research on vehicle suspension elements: the ball joints. The worn surface roughness of selected ball pins and their bearings was compared in terms of vehicle mileage, utilization period, and car model. Ball pin roughness was measured using a scanning tunneling microscope (STM), whereas for the bearing surface, a profilometer was used. The aim of this study was to determine the resistive torque in an unloaded ball joint. Using the finite element method, models of the unloaded ball joint were analyzed in two scenarios: with and without interference between the worn ball and its bearing. Calculated values of resistive torques in the ball joint were compared, and recommendations were given relative to the mileage and the time after which it was necessary to perform verification or replacement of the ball joints.

Motion simulation of Bionic Auxiliary Device for Ankle Rehabilitation based on small driving moment function

A kind of auxiliary device for ankle rehabilitation based on a ball pin vice is introduced in this paper first. The device has two degrees of freedom, while three-dimensional movement of the ankle can be achieved approximately. The modeling and simulation process of the ankle joint rehabilitation device are described in this paper. Motion simulation is preceded by using ADAMS for researching its dynamics and kinematics performance when the upper platform adopts small driving moment function to control the movement. The results are compared with the results of motion simulation driven by modified constant velocity function. The results show that the maximum driving torque of the motor driven by the small driving moment function is less than the maximum driving torque of the motor driven by the modified constant velocity function, which has a certain effect on saving energy consumption of the motor.

WITHDRAWN: Performance analysis of mineral oil based nano-lubricants with sulphur impregnated reduced graphene oxide nanosheets

Abstract Nano lubricants offer a great advantage in increasing the performance of the refrigeration systems by improving the tribological properties. Researchers found out that better lubrication properties can be achieved through nanolubricants by adding nanoparticles at optimum concentrations to the base lubricating oils. Reduction in frictional coefficients and wear rates contribute to the improvement of COP. Theobjective of the present work is to reduce the frictional coefficients and specific wear rate by adding reduced grapheneoxide (RGO) based hybrid nanomaterial to the lubricating oil (R134a oil) used in the refrigerator compressors. The RGO was synthesized by using modified hummers method, which was then impregnate with sulphur to obtain sulphur - reduced graphene oxide (SRGO) nanosheets. The nanolubricant was prepared by dispersing (SRGO) nanosheets in mineral oil using ultrasonic agitation. The dispersion stability and morphology studies were conducted using DLS and FTIR. Tribological studies were conducted using 4 ball friction tester and pin on disc tester. The thermophysical properties of the nanolubricants like thermal conductivity and viscosity were also estimated. The friction coefficient was found to decrease by 11% for addition of 0.1% by volume of SRGO nanosheets in mineral oil. The viscosity of nanolubricant containing 0.1% of SRGO nanosheets was 6.6% higher than base oil.

Model Experimental Study of Man-Machine Interactive Robot-Assisted Craniotomy.

To evaluate the feasibility, safety, and accuracy of the new man-machine interactive robotic system in model experiment. The implantation of the 8 to 10 bone screws over the skull model obtained from real patient's digital imaging and communications in medicine (DICOM), three-dimensional spiral computed tomography (CT) scans were taken. The end of the robotic arm was replaced with standard parts (including marker ball) for cone beam computed tomography (CBCT) scanning. The marker ball and marker pin were segmented and marked and exported via txt format. The position of the robotic end and model was obtained through the conversion of spacious position of standard parts and the executive end was replaced eventually. The water balloon was placed inside the skull model to imitate the dura mater and the destruction was documented for the system's safety. The system accuracy was evaluated by the error between the actual drilling position and the virtual plan and selection of 14 points of the skull window of milling pathway, monitored intraoperatively via Micron Tracker system and the overall skull window overlapped percentage via Mimics. Five model experiments were successfully performed with the average registration time of 3 minutes without destruction of balloon. The error of the outer table was 0.85 ± 0.45 mm, the inner table was 0.78 ± 0.49 mm, the line segment error of milling cutter was 0.93 ± 0.50 mm and the overall skull window overlapped percentage was 97.37% ± 0.78%. The system shows safety, accuracy, and reliability which can be an optional assistant method for craniotomy in the future.

Hot and warm cross-wedge rolling of ball pins – Comparative analysis

Cross-wedge rolling is a process conducted mainly in hot forming conditions. Warm forming is a compromise between hot and cold forming. This paper presents the results of a comparative analysis of warm and hot rolling of ball-shaped pins. Rolling process was controlled in terms of energy consumption, load and abrasive wear of tools. Warm cross-wedge rolling is more economical due to the low energy consumption required to heat the billet. Warm rolling can be less cost-effective due to faster tools wear. Faster tool wear during rolling in warm conditions may generate additional cost connected to regeneration and more frequent tool replacement. The stress and strain during the rolling at different temperatures was analysed. The variable nature of stress during cross-wedge rolling is more advantageous during hot rolling due to the lower amplitude of stress changes. Particular attention was paid to the quality of elements and difficulties resulting from rolling at lower temperatures. The influence of the rolling temperature on the quality of the microstructure of the rolled products was demonstrated. It was proved that during the warm rolling, the material may be strengthened due to deformation.

Differential Crosstalk Mitigation in the Pin Field Area of SerDes Channel With Trace Routing Guidance

Crosstalk noise on the printed circuit board is usually decreased by adding shielding ground (GND). In the trace routing area, the shielding vias are added to isolate the coupling between different traces. In the ball gate array (BGA) and pin field area, assigning more GND pins has demonstrated the effectiveness of crosstalk reduction between signals. However, such design decreases the signal to ground (S:G) ratio dramatically, herein, it is not suitable for applications that require high signal pin density. Unlike the treatment in the conventional methodology, in this paper, the differential crosstalk is mitigated by using the principle of symmetry on two adjacent differential signal pairs in the BGA and pin field regions. New full pin map patterns are proposed and compared with the conventional full pin map patterns. Without sacrificing the S:G ratio, the proposed maps prove the superiority in mitigating both differential far-end and near-end integrated crosstalk noise. To maintain the low crosstalk level in the entire link path, guidance of differential trace routing is provided and demonstrated in the details. All models in this paper satisfy SerDes channel designing and manufacturing requirements.

Research on an Ankle Joint Auxiliary Rehabilitation Robot with a Rigid-Flexible Hybrid Drive Based on a 2-S'PS' Mechanism.

An ankle joint auxiliary rehabilitation robot has been developed, which consists of an upper platform, a lower platform, a dorsiflexion/plantar flexion drive system, a varus/valgus drive system, and some connecting parts. The upper platform connects to the lower platform through a ball pin pair and two driving branch chains based on the S′PS′ mechanism. Although the robot has two degrees of freedom (DOF), the upper platform can realize three kinds of motion. To achieve ankle joint auxiliary rehabilitation, the ankle joint of patients on the upper platform makes a bionic motion. The robot uses a centre ball pin pair as the main support to simulate the motion of the ankle joint; the upper platform and the centre ball pin pair construct a mirror image of a patient's foot and ankle joint, which satisfies the human body physiological characteristics; the driving systems adopt a rigid-flexible hybrid structure; and the dorsiflexion/plantar flexion motion and the varus/valgus motion are decoupled. These structural features can avoid secondary damage to the patient. The rehabilitation process is considered, and energy consumption of the robot is studied. An experimental prototype demonstrates that the robot can simulate the motion of the human foot.

A helical wedge rolling process for producing a ball pin

Abstract The paper describes a new metal forming process called Helical Wedge Rolling (HWR). Combining the advantages of cross wedge rolling and skew rolling methods, this process allows for continuous forming of axisymmetric parts. HWR is characterized by high efficiency and low material losses. What may present a difficulty is the design of tools that will enable the formation of parts with required shape. To overcome this and ensure effective design, numerical modelling is performed. The paper describes the numerical modelling of a HWR process for a ball pin. The paper also presents the design of a stand for rolling tests (prototype helical-wedge rolling mill) and experimental results (obtained output: 30 pieces per minute).

Failure analysis of the balance ball pin in the car steering system

Abstract A balance ball pin used in the car steering system was found broken into two pieces. An evaluation of the failed part was investigated to determine the cause of failure and assess its integrity. Mechanical properties tests of the material are conducted first. Macroscopic examinations, scanning electronic microscopy(SEM) examination, metallographic examination,hardness measurement and chemical composition analysis were all conducted. The results indicated that fatigue fracture is the main fracture mode, and the uneven quench treatment led to the inhomogeneous thickness of quench-hardened case. As a result, in the fluctuations load, microcracks along the circumferential direction emerged on the subsurface of the quench-hardened case. Moreover, due to poor assembly, the stabilizer bar didn't turn smoothly in the working and fitting surface was worn badly, where produced the large resistance, which is the main torque to the ball pin.

Cavity formation in cross-wedge rolling processes

The problem of end-face cavity formation in parts produced by cross-wedge rolling was studied in order to reduce material consumption. The cavity depth was measured by the displacement method. Twenty-one different cases of rolling were analysed by finite element method to determine the effects of process parameters such as the wedge tool angle, the temperature of material, the tool velocity and the reduction ratio on the depth of end-face cavities. Relationships between these parameters are examined in order to establish dependencies enabling quick and simple selection of a concavity allowance in order to remove the cavities. The equations for calculating the concavity allowance were verified in an experimental process for manufacturing ball pins with the use of flat tools. Rolling tests were performed using a billet with its length selected in compliance with the established dependencies. The experimental results demonstrate that the proposed solution is a viable method for end-face cavity removal.

Tribological behaviour of MoS2-based self-lubricating laser cladding for use in high temperature applications

Abstract Many high temperature (HT) forming processes require the use of solid lubricants in order to control friction and reduce wear. In an attempt to eliminate the need for solid lubrication in high temperature sliding applications, nickel-based self-lubricating coatings with the addition of Ag and MoS2 were prepared by means of laser cladding on stainless steel substrates. The behaviour of the resulting laser claddings was thoroughly evaluated up to 600 °C, including the oxidation behaviour and reciprocating tribotesting using different counter body geometries (ball and flat pin). The self-lubricating coatings showed lower friction than the unmodified reference alloy at all tested temperatures, in addition to a significant microstructural stability after prolonged exposure at high temperatures. The addition of solid lubricants to the claddings was also found to be beneficial in terms of the counter body wear at HT, as no material loss could be measured for the bearing balls after testing at 600 °C against the self-lubricating claddings, despite the significant softening experienced by AISI 52100 bearing steel at HT.

Simulation and Analysis of One-time Forming Process of Automobile Steering Ball Head

Aiming at the problems such as large machining allowance, low production efficiency and material waste during die forging of ball pin, the cold extrusion process of ball head was studied and the analog simulation of the forming process was carried out by using the finite element analysis software DEFORM-3D. Through the analysis of the equivalent stress strain, velocity vector field and load-displacement curve, the flow regularity of the metal during the cold extrusion process of ball pin was clarified, and possible defects during the molding were predicted. The results showed that this process could solve the forming problem of ball pin and provide theoretical basis for actual production of enterprises.

Simulation Analysis of Bionic Auxiliary Device for Ankle Rehabilitation Based on ADAMS

A kind of auxiliary device for ankle rehabilitation based on a ball pin vice is introduced in this paper first. The device has two degrees of freedom, while three-dimensional movement of the ankle can be achieved approximately. Motion simulation is preceded by using ADAMS for researching its dynamics and kinematics performance when the upper platform adopts three motion rules to control the movement. The modeling and simulation of the device are described in this paper. The analysis results can be used to optimize structure and determine its characteristic parameter. A process of this research can be as a reference for mechanism analysis of more motion models.