A Thermal-Based Spindle Bearing Load Controller: Preliminary Experimental Evaluation

2002 ◽  
Author(s):  
John E. Harder ◽  
Jeffrey L. Stein
Keyword(s):  
Experimental Evaluation ◽  
High Speed ◽  
Metal Cutting ◽  
Dynamic Performance ◽  
Electric Heating ◽  
Process Conditions ◽  
Thermally Induced ◽  
Significant Control ◽  
Bearing Load ◽  
Bearing Loads

Thermally induced bearing loads are a serious problem for high-speed machining spindles used in metal cutting. Ideally, the bearing loads can be set to provide the necessary spindle stiffness to achieve the desired dynamic performance, while at the same time achieving long bearing life. Unfortunately, this is difficult to do because many process conditions affect these loads, sometimes in difficult to predict ways with significant degradation of spindle performance and life. The purpose of this paper is to describe a preliminary experimental evaluation of controlling bearing loads by controlling the heat generated by a thermal actuator placed around the spindle housing. A box spindle modified with an electric heating tape placed around its front ball bearings is used for this evaluation. The results show that significant control over the bearing load can be achieved for the conditions tested. However, it is discovered that asymmetrical placement of the heater with respect to the pair of back-to-back angular-contact bearings makes it difficult to regulate the loads on each bearing to the set point. Solutions to this problem are discussed and further research outlined. Nevertheless, the feasibility of the control of thermally induced bearing spindle loads with an externally mounted heater appears promising.

Modeling and Analysis for Thermal Control of Spindles for Reconfigurable Machines

2001 ◽  
Author(s):  
Jeffrey L. Stein ◽  
John E. Harder
Keyword(s):  
High Speed ◽  
Metal Cutting ◽  
Closed Loop ◽  
Dynamic Performance ◽  
Thermal Control ◽  
Open Loop ◽  
Limiting Factor ◽  
Process Conditions ◽  
Bearing Load ◽  
Bearing Loads

Abstract Control of thermally induced bearing loads remains an important but unsolved problem for precision, high-speed, metal cutting, machining spindles. Spindle dynamic performance, as well as spindle life, depends on bearing loads. Because these loads can change drastically with a change in process conditions, poor spindle dynamic performance, and dramatically reduced bearing life can result. The purpose of this paper is to evaluate the feasibility of controlling bearing loads by controlling the heat generated by a thermal actuator placed around the housing of the spindle. A mathematical model of the open loop response of a laboratory prototype spindle is developed and validated. The model is then used to evaluate the closed loop performance. The results show that closed loop control of the bearing load is achievable in steady state and under bandwidth limited transient conditions. The proposed system has reasonable command authority when additional heat is required, however, it is possible for the system to lose control when the heater is required to “provide” negative heat. This situation can be mitigated by proper choice of initial preload. As expected, measurement noise limits the control gain but is not a limiting factor. More open loop tests are suggested to validate the model under a broader set of conditions. In addition, closed loop validation is suggested. However, based on results obtained it appears bearing load control is achievable by controlling the thermal field around the spindle.

Controlling Both Thermally Induced Loads in Back-to-Back Angular Contact Spindle Bearings

2004 ◽  
Author(s):  
John E. Harder ◽  
Jeffrey L. Stein
Keyword(s):  
Metal Cutting ◽  
Electric Heating ◽  
Load Control ◽  
Future Research ◽  
Thermally Induced ◽  
Significant Control ◽  
Bearing Load ◽  
Bearing Loads ◽  
Improved Performance ◽  
The Individual

Thermally induced bearing loads may cause serious problems for metal cutting spindles when used at high speeds. While proper spindle bearing setup can help minimize this problem, ultimately the plethora of factors that cause the loads to vary cannot be accounted for by the setup. Previous work has shown that bearing load control is possible, but that improved performance may be realized if the temperature environment of each bearing of a back-to-back pair is considered separately. The purpose of this paper is to provide the results of an experimental evaluation of a bearing load control strategy using two thermal actuators. A box spindle was modified and two electric heating tapes were placed around the front pair of back-to-back angular contact ball bearings, one around each bearing. Significant control over the bearing loads can be achieved for the conditions tested including some level of independent control. Unfortunately, there is cross-talk between the heat actuators and the bearing loads, and this interferes with the level of independent load control that can be achieved over the individual bearings. The significance of this issue is discussed and future research outlined. The authors conclude that it is possible to significantly reduce the transient load variation in both bearings with two rather than one actuator; additionally, the second control loop usually improves the steady-state behavior over that achievable with single heater placed over the rear bearing.

Measurement of Thermally Induced Loads in Back-to-Back Angular Contact Spindle Bearings Using Strain Gauges

2004 ◽  
Author(s):  
John E. Harder ◽  
Jeffrey L. Stein
Keyword(s):  
Metal Cutting ◽  
Strain Gauges ◽  
Future Research ◽  
Axial Loads ◽  
Thermally Induced ◽  
Outer Race ◽  
Repeatability Error ◽  
Bearing Load ◽  
Bearing Loads ◽  
Set Up

Thermally induced bearing loads can potentially create serious problems for metal cutting spindles when used at high speeds. Proper spindle bearing set-up can minimize, but cannot eliminate this problem. Measuring the thermally induced load can alert the user to a potential problem or can be used to control the load directly. The purpose of this paper is to describe the design of a thermally induced bearing load sensor using strain gauges placed around the outer race. A box spindle with strain gauges on a pair of angular contact ball bearings located in the front of the spindle is used in this analysis. In order to calculate the thermally induced bearing load, the outputs of the strain gauges were recorded over a one second interval, sampled at 7500 Hz from each strain gauge and the root mean square of the deviation of this data from its mean is calculated. This value is a measure of the ball load. This calculated output is calibrated by a quadratic regression of these data to applied axial loads over a range of 0 to 2800 N. Values for each bearing were averaged to yield a front and rear value. The repeatability error for the front bearing sensor is 1.36%, and its accuracy is 98.9%. The repeatability error for the rear bearing sensor is 2.17% and its accuracy is 98.3%. These relatively low repeatability errors are attributable in part to filtering that does reduce the sensors’ bandwidth, but not significantly for measuring the relatively slowly changing thermally induced loads. Sensor design improvements and potential avenues of future research are discussed.

scholarly journals Improvement of Tilting-Pad Journal Bearing Operating Characteristics by Application of Eddy Grooves

Lubricants ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 18
Author(s):  
Eckhard Schüler ◽  
Olaf Berner
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Load Capacity ◽  
Fluid Film ◽  
Operating Characteristics ◽  
Fluid Film Bearings ◽  
Tilting Pad ◽  
Bearing Load ◽  
Bearing Loads ◽  
Tilting Pad Journal Bearing

In high speed, high load fluid-film bearings, the laminar-turbulent flow transition can lead to a considerable reduction of the maximum bearing temperatures, due to a homogenization of the fluid-film temperature in radial direction. Since this phenomenon only occurs significantly in large bearings or at very high sliding speeds, means to achieve the effect at lower speeds have been investigated in the past. This paper shows an experimental investigation of this effect and how it can be used for smaller bearings by optimized eddy grooves, machined into the bearing surface. The investigations were carried out on a Miba journal bearing test rig with Ø120 mm shaft diameter at speeds between 50 m/s–110 m/s and at specific bearing loads up to 4.0 MPa. To investigate the potential of this technology, additional temperature probes were installed at the crucial position directly in the sliding surface of an up-to-date tilting pad journal bearing. The results show that the achieved surface temperature reduction with the optimized eddy grooves is significant and represents a considerable enhancement of bearing load capacity. This increase in performance opens new options for the design of bearings and related turbomachinery applications.

Reduced Order Finite Element Modeling of Thermally Induced Bearing Loads in Machine Tool Spindles

1999 ◽  
Author(s):  
Alex O. Gibson ◽  
Jeffrey L. Stein
Keyword(s):  
Finite Element ◽  
Thermal Expansion ◽  
Machine Tool ◽  
Mechanical Load ◽  
Machining Process ◽  
Thermally Induced ◽  
Reduced Order ◽  
Wide Range ◽  
Bearing Load ◽  
Bearing Loads

Abstract Machine tool spindle bearings are subjected to a large range of axial and radial loads due to the machining process. Further the rotating spindle must be extremely stiff to minimize the cutting tool’s deflection. The high spindle stiffness is achieved by applying a mechanical load to the bearings, the preload. In fixed preload spindles the bearing loads tend to increase with increasing spindle speed due to thermal expansion and it is well established that these thermally induced loads can lead to premature bearing failure. A model of thermally induced bearing load in angular contact bearing spindles is developed that includes an axis-symmetric reduced order finite element model of the heat transfer and thermal expansion within the spindle’s housing and shaft and the bearing and shaft dynamics. Nodal reduction is used in the reduced order model to minimize the number of temperature states and the computational load. The reduced order model’s calculated temperature and bearing load values are shown to closely match experimentally measured values over a wide range of spindle speeds. The paper ends with a parameter variation study which predicts a dramatic decrease in the thermally induced bearing load when silicon nitride balls are substituted for steel balls.

scholarly journals Mathematical Modeling on Statics and Dynamics of Aerostatic Thrust Bearing with External Combined Throttling and Elastic Orifice Fluid Flow Regulation

Lubricants ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 57 ◽  
Author(s):  
Vladimir Kodnyanko ◽  
Stanislav Shatokhin ◽  
Andrey Kurzakov ◽  
Yuri Pikalov
Keyword(s):  
Mathematical Modeling ◽  
High Speed ◽  
Metal Cutting ◽  
Load Capacity ◽  
Dynamic Performance ◽  
Performance Criteria ◽  
Design Parameters ◽  
Machining Accuracy ◽  
Aerostatic Bearing ◽  
Aerostatic Bearings

As aerostatic bearings are used in high-speed metal-cutting machines to increase machining accuracy, there is the need to improve their characteristics, including compliance, which is usually high. In practical applications, a significant reduction of bearing compliance is often necessary, sometimes down to zero and even negative values, to ensure automatic compensation of the elastic deformation in the machine technological system. A decrease in compliance leads to deterioration in the dynamic performance of the bearing, so it is necessary to develop new designs that meet the above requirements. This article considers an aerostatic bearing, in which decrease in compliance is ensured by the use of air throttling with elastic orifices. To ensure its stability, the principle of combined external throttling was applied, which can substantially improve the dynamics of conventional aerostatic bearings. A mathematical model of the elastic orifice deformation was developed, together with the flow rate performance calculation method. The method ensured full qualitative and satisfactory quantitative agreement with the experimental data. The model was used in the mathematical modeling of the aerostatic bearing movement. The article also proposes a method to calculate the static load capacity and compliance of a bearing, as well as a numerical method for fast computation of its dynamic performance, which allows for real-time multi-parameter optimization by the bearing dynamic performance criteria. The study showed that there is an optimal set of design parameters for which low, zero, and negative static compliance of the bearing is ensured, with the necessary stability margin, high speed, and the non-oscillatory nature of the transient processes.

Ball bearing turbocharger vibration management: application on high speed balancer

2020 ◽  
Vol 21 (6) ◽  
pp. 619
Author(s):  
Kostandin Gjika ◽  
Antoine Costeux ◽  
Gerry LaRue ◽  
John Wilson
Keyword(s):  
Dynamic Behavior ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Ball Bearing ◽  
Squeeze Film ◽  
Design And Technology ◽  
Squeeze Film Damper ◽  
Damping Coefficients ◽  
Bearing Loads ◽  
Stiffness And Damping

Today's modern internal combustion engines are increasingly focused on downsizing, high fuel efficiency and low emissions, which requires appropriate design and technology of turbocharger bearing systems. Automotive turbochargers operate faster and with strong engine excitation; vibration management is becoming a challenge and manufacturers are increasingly focusing on the design of low vibration and high-performance balancing technology. This paper discusses the synchronous vibration management of the ball bearing cartridge turbocharger on high-speed balancer and it is a continuation of papers [1–3]. In a first step, the synchronous rotordynamics behavior is identified. A prediction code is developed to calculate the static and dynamic performance of “ball bearing cartridge-squeeze film damper”. The dynamic behavior of balls is modeled by a spring with stiffness calculated from Tedric Harris formulas and the damping is considered null. The squeeze film damper model is derived from the Osborne Reynolds equation for incompressible and synchronous fluid loading; the stiffness and damping coefficients are calculated assuming that the bearing is infinitely short, and the oil film pressure is modeled as a cavitated π film model. The stiffness and damping coefficients are integrated on a rotordynamics code and the bearing loads are calculated by converging with the bearing eccentricity ratio. In a second step, a finite element structural dynamics model is built for the system “turbocharger housing-high speed balancer fixture” and validated by experimental frequency response functions. In the last step, the rotating dynamic bearing loads on the squeeze film damper are coupled with transfer functions and the vibration on the housings is predicted. The vibration response under single and multi-plane unbalances correlates very well with test data from turbocharger unbalance masters. The prediction model allows a thorough understanding of ball bearing turbocharger vibration on a high speed balancer, thus optimizing the dynamic behavior of the “turbocharger-high speed balancer” structural system for better rotordynamics performance identification and selection of the appropriate balancing process at the development stage of the turbocharger.

Dynamic Performance of High-Speed Electric Multiple Unit within Multi-Body System Simulation

2019 ◽  
Vol 12 (4) ◽  
pp. 339-349
Author(s):  
Junguo Wang ◽  
Daoping Gong ◽  
Rui Sun ◽  
Yongxiang Zhao
Keyword(s):  
High Speed ◽  
Rapid Development ◽  
Dynamic Performance ◽  
Body System ◽  
High Speed Railway ◽  
Evaluation Indexes ◽  
Actual Operation ◽  
Multiple Unit ◽  
The Stability ◽  
Multi Body

Background: With the rapid development of the high-speed railway, the dynamic performance such as running stability and safety of the high-speed train is increasingly important. This paper focuses on the dynamic performance of high-speed Electric Multiple Unit (EMU), especially the dynamic characteristics of the bogie frame and car body. Various patents have been discussed in this article. Objective: To develop the Multi-Body System (MBS) model of EMU, verify whether the dynamic performance meets the actual operation requirements, and provide some useful information for dynamics and structural design of the proposed EMU. Methods: According to the technical characteristics of a typical EMU, a MBS model is established via SIMPACK, and the measured data of China high-speed railway is taken as the excitation of track random irregularity. To test the dynamic performance of the EMU, including the stability and safety, some evaluation indexes such as wheel-axle lateral forces, wheel-axle lateral vertical forces, derailment coefficients and wheel unloading rates are also calculated and analyzed in detail. Results: The MBS model of EMU has better dynamic performance especially curving performance, and some evaluation indexes of the stability and safety have also reached China’s high-speed railway standards. Conclusion: The effectiveness of the proposed MBS model is verified, and the dynamic performance of the MBS model can meet the design requirements of high-speed EMU.

Dynamic Performance of HTS Maglev and Comparisons with Another Two Types of High-Speed Railway Vehicles

Cryogenics ◽  
2021 ◽  
pp. 103321
Author(s):  
Yuhang Yuan ◽  
Jipeng Li ◽  
Zigang Deng ◽  
Zhehao Liu ◽  
Dingding Wu ◽  
...  
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
High Speed Railway ◽  
Railway Vehicles ◽  
Hts Maglev
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