Wyniki wyszukiwania - BazTech

1

Analysis of screw connection in air conditioning systems

Jírová Radka, Pešík Lubomír

Zeszyty Naukowe. Transport / Politechnika Śląska

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2022

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z. 114

43--54

EN

Air conditioning systems in vehicles require long-term reliability during their entire service life. Especially, a good sealing function is needed for the prevention of coolant leaking. Unfortunately, in specific cases, after a particular time, screw connections of the air conditioning circuit lose their tightness, and the coolant starts to leak. Therefore, this paper focuses on the analysis and design optimisation of screw connections. We used the finite element method for describing the sealing, screw and disc spring behaviour. Then, we proposed a new design of the disc spring to obtain the proper force-deformation characteristics of the connection and ensure the tightness of the screw connection.

2

Pneumatic vibroisolation system of the base desk with natural frequency regulation

Jírová Radka, Pešík Lubomír

Zeszyty Naukowe. Transport / Politechnika Śląska

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2021

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z. 113

91--100

EN

Vibroisolation systems of base desks for machine and testing facilities usually cannot effect efficient changing of their own frequencies according to operating conditions. Especially in the case of the automotive industry, the possibility of changing natural frequencies is very desirable. During varying operating conditions, the vibroisolation system needs to be regulated easily and quickly regarding the minimisation of dynamical forces transmitted to the ground and to ensure the stability of the testing process. This paper describes one of the options of tuning the base desk at a relatively short time and by sufficient change of own frequencies, which decides the dynamical behaviour of the whole system.

3

Identification and verification of dynamic parameters for the welding manipulator

Jírová Radka, Pešík Lubomír

Zeszyty Naukowe. Transport / Politechnika Śląska

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2020

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z. 106

51--61

EN

Welding production lines are indispensable parts of the production processes in the automotive industry. In many cases, the production line operation is ensured by equipment with linear conveyors or robots, wherein linear guiding systems are basic elements of these manipulators. The failure of some linear guiding system may lead to significant production losses. Hence, the knowledge of their operating loads is necessary to determine very exactly. The objective of this article is to identify and verify the basic dynamic parameters of the welding manipulator, as a starting point for the operating loads calculation of linear guiding systems. This issue was solved by combining the measurement of kinematic values and MBS (Multi-body System) analysis in case of the concrete linear welding manipulator, which was the main part of the observed welding line. We have measured time values of acceleration in defined points of the manipulator and evaluated them by FIR (Finite Impulse Response) filter, FFT (Fast Fourier Transformation) analysis and ODS (Operating Deflection Shapes) analysis. The obtained frequency spectrum showed oscillation frequencies, which could be compared with frequencies of the manipulator dynamical model by different mass and stiffness parameters. In this way, the dynamic parameters of the welding manipulator can be identified and used for the next calculations and simulations, where loads of linear guiding systems will produce very important results.

4

Dynamic load of linear guiding systems in handling machines

Jírová Radka, Pešík Lubomír

Zeszyty Naukowe. Transport / Politechnika Śląska

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2019

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z. 103

31--41

EN

Linear guiding systems are used in machines for relative translational motion of components, especially for handling devices, which are the basis of production lines. In these operating conditions, the linear guiding systems are dynamically loaded. Dynamical influences may lead to the decrease and damage of bearings. The aim of this paper was to calculate dynamical influences of a mass inertia on linear guiding systems. This issue was solved by a numerical calculation of differential motion equations in 2D. The motion was calculated on an example of a handling machine for welding car bodies. The result is a percentage representation of the dynamic forces on the total load of the linear guiding systems. The result shows the percentage representation in the solved case as more than 10%.