Axial Load Capacity of Water-Lubricated Hydrostatic Conical Bearings With Spiral Grooves (On the Case of Rigid Surface Bearings)

1996 ◽  
Vol 118 (4) ◽  
pp. 893-899 ◽  
Author(s):  
S. Yoshimoto ◽  
Y. Anno ◽  
M. Tamura ◽  
Y. Kakiuchi ◽  
K. Kimura
Keyword(s):  
High Speed ◽  
Printed Circuit Boards ◽  
Load Capacity ◽  
Water Pressure ◽  
Circuit Boards ◽  
The Finite Element Method ◽  
Rotating Shaft ◽  
Pressurized Water ◽  
Axial Load Capacity ◽  
Spiral Grooves

This paper describes the static characteristics of water-lubricated hydrostatic conical bearings with spiral grooves. Hydrostatic conical bearings treated here have been designed for high speed spindles and are intended to apply to spindles for drilling small holes of printed circuit-boards. Pressurized water is first fed to the inside of the rotating shaft and supplied to spiral grooves on the shaft surface through feeding holes. Therefore, water pressure is greatly increased at outlets of feeding holes due to the centrifugal force by shaft rotation. Furthermore, water pressure is also increased by the viscous pump effect of spiral grooves. Water pressures in the bearings under concentric condition are numerically obtained by using the finite element method and calculated results are compared with experimental ones. It is consequently found that this water-lubricated hydrostatic conical bearings with spiral grooves are very suitable for precision high speed spindles.

Stability of Water-Lubricated, Hydrostatic, Conical Bearings With Spiral Grooves for High-Speed Spindles

2001 ◽  
Vol 124 (2) ◽  
pp. 398-405 ◽  
Author(s):  
S. Yoshimoto ◽  
S. Oshima ◽  
S. Danbara ◽  
T. Shitara
Keyword(s):  
High Speed ◽  
Water Pressure ◽  
Rotating Shaft ◽  
Pressurized Water ◽  
High Speeds ◽  
Theoretical Predictions ◽  
The Stability ◽  
Stability Of Water ◽  
Spiral Grooves ◽  
Good Agreement

In this paper, the stability of water-lubricated, hydrostatic, conical bearings with spiral grooves for high-speed spindles is investigated theoretically and experimentally. In these bearing types, pressurized water is first fed to the inside of the rotating shaft and then introduced into spiral grooves through feeding holes located at one end of each spiral groove. Therefore, water pressure is increased due to the effect of the centrifugal force at the outlets of the feeding holes, which results from shaft rotation. In addition, water pressure is also increased by the viscous pumping effect of the spiral grooves. The stability of the proposed bearing is theoretically predicted using the perturbation method, and calculated results are compared with experimental results. It was consequently found that the proposed bearing is very stable at high speeds and theoretical predictions show good agreement with experimental data.

Influence of the Manufacturing Accuracy of the Planetary Cycloid Gear on the Positioning Accuracy of the Parallel Robot

2021 ◽  
pp. 13-21
Author(s):  
S.V. Palochkin ◽  
Y.V. Sinitsyna ◽  
K.G. Erastova
Keyword(s):  
High Speed ◽  
Printed Circuit Boards ◽  
Parallel Robot ◽  
Circuit Boards ◽  
Positioning Accuracy ◽  
Printed Circuit ◽  
Serial Robots ◽  
Sequential Structure ◽  
Robot Positioning ◽  
Manufacturing Accuracy

The increased accuracy in high-speed positioning of the parallel robot effector in comparison with that of serial robots with a sequential structure is often the main reason for their use in various modern industries, such as the manufacture of printed circuit boards for microelectronics. However, despite the higher theoretical positioning accuracy, due to the kinematic structure of the parallel robot, in practice this characteristic largely depends on the accuracy of manufacturing individual elements of this mechanism, the most important of which are the gearboxes of the drives of its input pairs. A solution to the urgent problem of determining the effect of the manufacturing accuracy of planetary pinion gearboxes included in the drive of a five-link parallel robot on the positioning accuracy of its output link is proposed. A specific relationship has been determined between the grade of accuracy number of the gear part dimensions and the robot positioning accuracy. The unevenness of the positioning accuracy along the coordinate axes of its working area is revealed. It was found that near the area of certain robot positions the accuracy of its positioning drops sharply.

Advanced Build-up Materials for High Speed Transmission Application

2018 ◽  
Vol 2018 (1) ◽  
pp. 000305-000309 ◽  
Author(s):  
Shiro Tatsumi ◽  
Shohei Fujishima ◽  
Hiroyuki Sakauchi
Keyword(s):  
High Speed ◽  
Printed Circuit Boards ◽  
Transmission Loss ◽  
Coefficient Of Thermal Expansion ◽  
Strip Line ◽  
Circuit Boards ◽  
Additive Process ◽  
Printed Circuit ◽  
Low Dielectric ◽  
Transmission Speed

Abstract Build-up process is a highly effective method for miniaturization and high density integration of printed circuit boards. Along with increasing demands for high transmission speed of electronic devices with high functionality, packaging substrates installed with semiconductors in such devices are strongly required to reduce the transmission loss. Our insulation materials are used in a semi-additive process (SAP) with low dielectric loss tangent, smooth resin surface after desmear, and good insulation reliability. Actually, the transmission loss of strip line substrates and Cu surface roughness impact on transmission loss were measured using our materials. Furthermore, low dielectric molding film with low coefficient of thermal expansion (CTE) and low Young's modulus are introduced.

scholarly journals Analytical Modeling of Metamaterial Differential Transmission Line Using Corrugated Ground Planes in High-Speed Printed Circuit Boards

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 299 ◽  
Author(s):  
Myunghoi Kim
Keyword(s):  
Analytical Model ◽  
High Speed ◽  
Printed Circuit Boards ◽  
Signal Transmission ◽  
Circuit Boards ◽  
Transmission Characteristics ◽  
Differential Signal ◽  
Printed Circuit ◽  
Full Wave ◽  
Differential Transmission

An analytical model for metamaterial differential transmission lines (MTM-DTLs) with a corrugated ground-plane electromagnetic bandgap (CGP-EBG) structure in high-speed printed circuit boards is proposed. The proposed model aims to efficiently and accurately predict the suppression of common-mode noise and differential signal transmission characteristics. Analytical expressions for the four-port impedance matrix of the CGP-EBG MTM-DTL are derived using coupled-line theory and a segmentation method. Converting the impedance matrix into mixed-mode scattering parameters enables obtaining common-mode noise suppression and differential signal transmission characteristics. The comprehensive evaluations of the CGP-EBG MTM-DTL using the proposed analytical model are also reported, which is validated by comparing mixed-mode scattering parameters Scc21 and Sdd21 with those obtained from full-wave simulations and measurements. The proposed analytical model provides a drastic reduction of computation time and accurate results compared to full-wave simulation.

scholarly journals Effect of Fiber Weave Structure in Printed Circuit Boards on Signal Transmission Characteristics

2019 ◽  
Vol 9 (2) ◽  
pp. 353 ◽  
Author(s):  
Bei Chen ◽  
Ruohe Yao ◽  
Hongfei Wang ◽  
Kuiwei Geng ◽  
Juan Li
Keyword(s):  
Dielectric Constant ◽  
High Speed ◽  
Printed Circuit Boards ◽  
Signal Transmission ◽  
Circuit Boards ◽  
Weave Structure ◽  
Line Parallel ◽  
Fluctuation Amplitude ◽  
Impedance Fluctuation ◽  
Constant Impedance

In this paper, we characterized and compared signal transmission performances of traces with different specifications of fiber weave. Measurements demonstrated that the dielectric constant, impedance fluctuation, and differential skew were all affected by fiber weave style. For flattened fiber weaves, the dielectric constant fluctuation reached 0.18, the impedance fluctuation amplitude was 1.0 Ω, and the differential skew was 2 ps/inch. For conventional fiber weaves, the three parameters were 0.44, 2.5 Ω, and 4 ps/inch respectively. Flattened fiber weave was more favorable for high-speed signal control. We also discussed the other methods to improve the fiber weave effect. It turned out that NE-glass (new electronic glass) fiber weave also had better performance in reducing impedance fluctuation and differential skew. Furthermore, made the signal traces and fiber weave bundles with an angle or designing the long signal line parallel to the weft direction both are simple and effective methods to solve this problem.

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