Experimental investigation of helical gear tooth crack location and depth detection using moving average method on transmission error

Gear systems are the most useful and essential power transmission systems in the high-speed industry due to their accuracy. It is necessary to make sure that these systems work without defects such as tooth cracks. Therefore, detecting the location and depth of cracks in gear systems is very important. In this research, a new approach is proposed to detect the crack location, and accordingly, some statistical indicators are used to estimate the crack depth in the helical gear tooth. To this end, after explaining the helical gear mesh stiffness and tooth-root crack modeling, the helical gear pair dynamic is modeled. Then, the vibration data of a helical gear system is obtained by an experimental test rig, and the moving average method is undertaken to precisely detect the crack location. The crack depth ratio is estimated using the crest factor, impulse factor, clearance factor, and [Formula: see text] and [Formula: see text] which are applied to the simulation results and the experimental signal. According to these results, the crest factor, impulse factor, and clearance factor calculated the crack depth ratio with a good agreement, and the indicators [Formula: see text] and [Formula: see text] estimated it with a more significant error. Also, the average of estimated values is calculated, indicating a better result than each indicator alone.

Smary do systemów przekładni – aktualne klasyfikacje i wymagania jakościowe

There are few normative specifications defining the requirements for lubricating greases, apart from greases for specialized military applications. The article presents the international classification of lubricants according to ISO 6743-99 Lubricants, industrial oils and related products (class L) – Classification – Part 99: General. The classification of greases is presented according to ISO 6743-9 Lubricants, industrial oils and related products (class L) – Classification – Part 9: Family X (Greases) and marking of greases according to ISO 12924 Lubricants, industrial oils and related products (Class L) – Family X (Greases) – Specification. For lubricants used in gear systems, the classification according to ISO 6743-6 Lubricants, industrial oils and related products (class L) – Classification – Part 6: Family C (Gears) was presented. Requirements for lubricating greases for gears have been collected in accordance with the current versions of PN-C-96015 Lubricants – Lubricating greases G – Classification and requirement, DIN 51826 Lubricants – Lubricating greases G – Classification and requirements and the project ISO/CD 12925-3 Lubricants, Industrial oils and related products (Class L) – Family C (gears). Part 3 – Specifications for greases for enclosed and open gear systems.

Design optimization analysis of an anti-backlash geared servo system using a mechanical resonance simulation and experiment

In many mechatronic systems, gear transmission chains are often used to transmit motion and power between motors and loads, especially for light, small but large torque output systems. Gear transmission chains will inevitably bring backlash as well as elasticity of shafts and meshing teeth. All of these nonlinear factors will affect the performance of mechatronic systems. Anti-backlash gear systems can reduce the transmission error, but elasticity has to be considered too. The aim of this paper is to find the key parameters affecting the resonance and anti-resonance frequencies of anti-backlash gear systems and then to give the design optimization methods of improving performance, both from element parameters and mechanical designing. The anti-backlash geared servo system is modeled using a two-inertia approximate model; a method of computing the equivalent stiffness of anti-backlash gear train is proposed, which comprehensively considers the total backlash of transmission chain, gear mesh stiffness, gear shaft stiffness and torsional spring stiffness. With the s-domain block diagram model of the anti-backlash geared servo system, the influences of four main factors on the resonance and anti-resonance frequencies of system are analyzed by simulation according to the frequency response, and the simulation analysis results dependent on torsional spring stiffness of anti-backlash gear pair and load moment of inertia variation are verified by the experiment. The errors between simulation and experimental results are less than 10 Hz. With these simulation and experiment results, the design optimization methods of improving the resonance and anti-resonance frequencies such as designing the center distance adjusting mechanism to reduce the initial total backlash, increasing the stiffness of torsional spring and lightweight design of load are proposed in engineering applications.