Sliding parts
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very day for the past 30 years, Techné has developed its knowledge in sealing and sliding parts. Technical and human investments coupled with external growth allow us today, to be a reliable partner for many renowned companies, without compromising the historical values of a family group. We invest in Asia as well as in Europe to be able to continually modernise our production units, in order to keep up with the evolution of our customers. We implement the most advanced technologies like surface treatments to increase the eco-efficiency of your systems. We set up a development policy which...

Sliding | Definition board Friction coefficient Coef. of thermal expansion First greased First greased Greased

Table content Wrapped bushings Special parts Sintered parts 174 Filters

Wrapped bushings

The information in this catalogue is based on the experience gained by Techné in the last decade of research on the development and manufacture of sliding products. It represents the current state of our knowledge and know-how. The sliding function of the products in this catalogue do no rely only on the component itself, but on the other parameters such as the assembly, the applied pressure, contact area, operating temperature, mechanical stress, media, liquids in contact, lubrication and any kind of outside dirt. Because of those high numbers of parameters, it is not possible to give...

Multipurpose and self-lubricant, TU bushes are composed with 4 layers: A solid lubricant layer (1) mix of PTFE and lead, from 0,01 to 0,05 mm thick provides a very high performance against wear and friction. A porous sintered bronze sliding layer (2), from 0,20 to 0,35 mm thick, for heat conductivity, dimensional stability and bonding of the solid lubricant. A steel backing (3) for an optimal mechanical resistance. For standard parts, external diameters are protected with a 0,005mm thick tin plating (4). PTFE+loads Sintered bronze Steel backing Tin plating fig.1 • Micrographic structure of...

2] Mechanical characteristics Properties 1. 220°C max, for TU bush with tin plating. After analysis of each layer, Techne provides data about chemical resistance. However, considering the wide variety of available materials and grades, compatibility tests before final selection are recommended. 9 Chemical resistance TU bushes resist to water, alcohols, glycols, solvents, gasoline, diesel, kerosene and most of mineral oils (T° lower than 100°C). However they can be damaged in some acid or alkaline solutions such as chloric, nitric, sul furic, acetic and formic acids. Techne also recommends...

4) Sliding performance 9 Wear mechanism During its lifetime, TU bushes undergo 3 different periods (fig.3): running-in period Running-in period Intermediate period After assembly, the sliding surface of TU bushes quickly runs in. The surplus of PTFE-based lubricant is planed down in favor of the sintered bronze sliding layer. Techné considers that the running-in period is over when the bronze layer appears for about 10 to 15% of the sliding surface. Apparent bronze turns to a verdigris color, due to the fretting corrosion phenomenon. Wear rate depends on PV factor, the running-in period...

Possible use in hydrodynamic system fig.5 • Data about variation of sliding coefficient Cf with PV factor Sliding coefficient of TU bushes (between 0,08 and 0,02) depends on several parameters. It first depends on the above mentioned wear periods: during running-in period and at the end of lifetime, sliding coefficient is at its highest level. During intermediate period, sliding coefficient is at its lowest level and sliding function is optimal (fig.6). Moreover, pressure, speed and temperature constraints impact directly the sliding function of the bush. See fig.5 in order to get an...

H . Di corresponds to the projected area of the bushing Axial load 24F ____________ π(Dc² - (De+4)²) Axial load 24F ____________ π(Dc² - (De+4)²) Reciprocating motion of the shaft Oscillating motion of the shaft with an angle α N.mm².m/s (W.mm²) One direction shaft rotation Cylindrical bushing Motion & load π(Di² - De²)/4 corresponds to the area of the washer Oscillating motion with an angle α Flanged bushing One direction shaft rotation H . Di corresponds to the projected area of the bushing π(Dc² - (De+4)²)/24 corresponds to the area of the flange Oscillating motion of the shaft with an...

The calculation of PV factor (pressure P multiplied by speed V) is specific to the application. It allows to determine if the dimensions of the chosen TU-bush are appropriate for the constraints. Use formula on the previous page to determine the PV factor. Calculated PV factor has to be lower than PV max of the bush : PVmax < PVmax So for TU bushes: PVmax < 1.8 (see table page 11 et fig.5, page 13) Also pressure P and speed V values must be lower than the acceptable ones of the TU bush, see table on page 11. Note: Maximal pressure Pmax and maximal speed Vmax of a given application may not...

6) Lifetime A bush lifetime depends on several parameters. Based on its experience, Techné suggests corrective factors according to pressure, speed, temperature, load, roughness and material of the shaft. However other unknown and uncountable parameters, which are specific to the application, can interfere. So the lifetime indicated hereafter remains for indication only. Static load Dynamic load Static load Dynamic load For reciprocating motion or for washer profile, ignore this factor fig.12 • Factor λ5 depending on loads on the cylindrical bushing Shaft material Alloy steel Hardened...

Linear movement An additional factor X7 for correction of translation length S must be taken into account: Let's take examples from the previous page. cylindrical bushing Load:90 kg speed N: 400 tr/min Di: 50 H_ 60 PV calculated on previous page: 0,31 Temperature: 40°C Roughness: Ra 0,6 Static load Shaft material: Chrome steel Lk = 1,0,9, 1,0,84, 1, 1,4,102, (0,31)-1 Lh = 970 hours Washer Load : 2000 kg Oscillating motion, Frequency N 30 Angle a: 20° Di: 20 De: 36 PV calculated on previous page: 0,17 Temperature: 20°C Roughness: Ra 0,8 Material of the friction part: carbon steel Lk = 092.1...