Rolling Fatigue Life and Reliability of Ball Screws

2007 ◽  
Author(s):  
Hirokazu Shimoda ◽  
Shigeo Shimizu ◽  
Katsuji Tosha ◽  
Yushi Otani
Keyword(s):  
Fatigue Life ◽  
Weibull Distribution ◽  
Test Data ◽  
Dynamic Load ◽  
Ball Screw ◽  
Test Machine ◽  
Load Rating ◽  
Life Test ◽  
Dynamic Load Rating ◽  
Fatigue Life Test

The experimental formula based on Lundberg-Palmgren theory has been used for the calculation of basic dynamic load rating of ball screws because its contact state resembles that of angular contact ball bearings. However, the compatibility between the theoretical and the actual rating life of ball screws has not been yet confirmed by life tests and probability theory. The inherent properties of ball screws are also not considered in this formula. In this paper, the authors deal with the development of ball screw life test machine and fatigue life test for ball screws with a total number of 31 test samples. Type and occurrence location of the initial failure of each sample are investigated. The fatigue life test data are analyzed with two and three parameters Weibull distribution functions. The basic dynamic load rating of the ball screws are also estimated from the life test data. The results are summarized as follows: (1) Initial failures are generated at the surface of the balls and the nut raceway as a spalling. (2) The life distribution of the test data fairy well fits three parameters Weibull distribution function. (3) Basic dynamic load rating, which is estimated by the life test, is approximately in agreement with that of manufacturer’s catalog.

Study on the Life Distribution and Reliability of Roller Based Linear Bearing

2007 ◽  
Author(s):  
Shigeo Shimizu ◽  
Hirokazu Shimoda ◽  
Katsuji Tosha
Keyword(s):  
Fatigue Life ◽  
Test Data ◽  
Dynamic Load ◽  
Distribution Functions ◽  
Load Rating ◽  
Life Test ◽  
Life Distribution ◽  
Dynamic Load Rating ◽  
Log Normal ◽  
Log Normal Distribution

A study on the life distribution and reliability for roller guides with cage is carried out with a total number of 90 test samples in two lots (Ns = 38 and 52), and fatigue life distribution functions, such as two and three parameters Weibull distribution, and log-normal distribution are used for analyzing the test data. The basic dynamic load rating formula standardized by ISO in 2004 is also compared with the life test data in relation to the effect of crowning on both ends of the carriage raceway. Weibull slope, compatibility of distribution functions and λbm factor are also examined.

Re-Evaluation of Basic Dynamic Load Rating and Life Formula for a Ball Screw

2007 ◽  
Vol 50 (1) ◽  
pp. 88-95 ◽  
Author(s):  
Shigeo Shimizu ◽  
Hirokazu Shimoda ◽  
Chandra Shekhar Sharma
Keyword(s):  
Dynamic Load ◽  
Ball Screw ◽  
Load Rating ◽  
Dynamic Load Rating

Effect of High Pressure Gaseous Hydrogen on Fatigue Properties of SUS304 and SUS316 Austenitic Stainless Steel

2018 ◽  
Author(s):  
Takashi Iijima ◽  
Hirotoshi Enoki ◽  
Junichiro Yamabe ◽  
Bai An
Keyword(s):  
High Pressure ◽  
Stainless Steel ◽  
Fatigue Life ◽  
Austenitic Stainless Steel ◽  
Room Temperature ◽  
Hydrogen Gas ◽  
Gaseous Hydrogen ◽  
Life Test ◽  
Air Atmosphere ◽  
Fatigue Life Test

A high pressure material testing system (max. pressure: 140 MPa, temperature range: −80 ∼ 90 °C) was developed to investigate the testing method of material compatibility for high pressure gaseous hydrogen. In this study, SSRT and fatigue life test of JIS SUS304 and SUS316 austenitic stainless steel were performed in high pressure gaseous hydrogen at room temperature, −45, and −80 °C. These testing results were compared with those in laboratory air atmosphere at the same test temperature range. The SSRT tests were performed at a strain rate of 5 × 10−5 s−1 in 105 MPa hydrogen gas, and nominal stress-strain curves were obtained. The 0.2% offset yield strength (Ys) did not show remarkable difference between in hydrogen gas and in laboratory air atmosphere for SUS304 and SUS316. Total elongation after fracture (El) in hydrogen gas at −45 and −80 °C were approximately 15 % for SUS304 and 20% for SUS316. In the case of fatigue life tests, a smooth surface round bar test specimen with a diameter of 7 mm was used at a frequency of 1, 0.1, and 0.01 Hz under stress rate of R = −1 (tension-compression) in 100 MPa hydrogen gas. It can be seen that the fatigue life test results of SUS304 and SUS316 showed same tendency. The fatigue limit at room temperature in 100 MPa hydrogen gas was comparable with that in laboratory air. The room temperature fatigue life in high pressure hydrogen gas appeared to be the more severe condition compared to the fatigue life at low temperature. The normalized stress amplitude (σa / Ts) at the fatigue limit was 0.37 to 0.39 for SUS304 and SUS316 austenitic stainless steels, respectively.

A SIMPLIFIED WAY OF ESTIMATING A DYNAMIC LOAD RATING FOR THRUST ROLLER BEARINGS

Tribologia ◽  
2020 ◽  
Vol 289 (1) ◽  
pp. 49-55
Author(s):  
Michał LIBERA
Keyword(s):  
Dynamic Load ◽  
Linear Interpolation ◽  
Load Rating ◽  
Rolling Bearings ◽  
Thrust Bearings ◽  
Bearing Angle ◽  
Speed Up ◽  
The Difference ◽  
Dynamic Load Rating ◽  
Selection Of

The method of calculating the bearing capacity of rolling bearings is described in the ISO 281 standard. The calculation procedure for roller thrust bearings presented there, depending on the value of the nominal bearing angle, requires the selection of one of two formulas. Then, using the table, one reads the value of the factor depending on the geometry of the bearing components. To facilitate and speed up calculations (and perhaps also increase their accuracy), this article proposes a formula that is adapted to numerical applications, replaces linear interpolation with a proper non-linear function and allows calculations to be made for a specific value of the nominal bearing angle, but not within the range of 15°. The difference between the values calculated according to the proposed formula and the value calculated according to ISO 281 is, on average, around 3%.

scholarly journals A Study on Failure Analysis and High Performance of Hydraulic Servo Actuator

2020 ◽  
Vol 10 (21) ◽  
pp. 7451
Author(s):  
Yong-bum Lee ◽  
Jong-won Park ◽  
Gi-chun Lee
Keyword(s):  
Fatigue Life ◽  
Accelerated Life Testing ◽  
Test Equipment ◽  
Life Testing ◽  
Life Test ◽  
Accelerated Life ◽  
Servo Actuator ◽  
Hydraulic Servo ◽  
Automotive Parts ◽  
Fatigue Life Test

Hydraulic servo actuator is used as the core actuator in tensile compression fatigue life test equipment as it operates the micro displacement very precisely at a high frequency and can be used continuously for a long period of time. Recently, the life expectancy of automobiles has been extended, the load conditions of accelerated life testing on auto parts have been increased, and the life test time and number of tests have increased significantly in order to secure the reliability of the guaranteed life of produced vehicles. Therefore, hydraulic servo actuators mounted on accelerated life testing equipment for automotive parts are essential for much higher performance and a longer life than those tested. However, small- and medium-sized companies that supply test equipment for the fatigue life of auto often fail to develop technology due to a lack of research personnel and the development budget compared to the capabilities of large automobile manufacturers, resulting in frequent breakdowns due to the technical overload of test equipment. In this study, servo actuators were used to test automotive parts, with a maximum output of 2 ton, a maximum frequency of 3.3 Hz and a maximum displacement of 50 mm. The hydraulic servo actuator, which was installed in the tensile compression fatigue life test equipment, failed to operate normally at the site, and by analyzing it, we realized this resulted from the heat generation of insulation compression due to the accumulation of air and gas into the hydraulic oil and the increase in friction due to the deterioration of flow. A static pressure bearing was adopted as a design change to improve the root cause for this failure mode, and a very high level of geometric concentricity was secured by inserting concentric tubes outside the labyrinth seal type piston. The newly designed and manufactured actuator is the result of research that has achieved a semi-permanent long life and improved performance up to 100 Hz by non-contact operation.

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