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Harald Nitzschke +49 (0) 7303 92874 - 0 nitzschke@ttv-gmbh.de
The GETRO-090 sliding bushings are rolled from a bronze strip with a high specific density. There are diamond-shaped or round lubricant grooves on the inner surface, incorporated as per the client's requirements.
This type of bushings is characterised by their high levels of resilience and long service lives. They take the place of the traditional bronze bushings, but are more economical and more compact. They are suitable for use in lifting vehicles and construction machinery, cars, tractors, trucks, machine tools and in the engine construction industry.
Rolled sliding bushing GETRO-092 (DZT)
The GETRO-092 bronze sliding bearings are equivalent to the GETRO-090 bushings, but with evenly distributed lubrication holes. The lubricant is dispensed into the holes during assembly. The GETRO-092 sliding bushings are characterised by their good lubricant capacity and simple assembly.
This type of sliding bushing is used with medium-sized loads and low speeds, such as in transport rollers, winding equipment, anchor winches and aligning machinery.
Compared to solid bronze bushes, CuSn8 sliding bushes require less installation space and are easier to install. At the same time, they offer
Standard sizes for CuSn8 sliding bushings are quickly available. Special sizes can also be realised easily and cost-effectively.
The bronze alloy CuSn8 has the ideal properties for highly stressed sliding connections:
This ensures that the CuSn8 sliding bushing does not deform plastically even under permanent pressure, but runs stably, e.g. in construction or agricultural machinery, in gearboxes or in heavy lifting systems. Even under high surface pressure, the sliding surface remains intact if the bearing is designed correctly.
ttv tip: If high loads and long running times are combined, diamond-shaped lubrication pockets are recommended for CuSn8 sliding bushings. These distribute the lubricant better and relieve the sliding surface evenly.
In the GETRO-090 CuSn8 sliding bushing
Lubrication pockets are milled into the sliding surface - either spherical or diamond-shaped, depending on customer requirements. These pockets absorb the lubricant during operation and release it again evenly. This is particularly effective in applications with high loads and frequent movements.
The GETRO-092 CuSn8 sliding bushin
works slightly differently: instead of pockets, it has regularly spaced lubrication holes. These holes are filled with grease or oil during assembly. They store more lubricant than pockets and also release it over a longer period of time - ideal if the bearing is difficult to access or if you want to establish longer maintenance intervals.
Mechanically, both sliding bushing are almost identical and are made of CuSn8 bronze, making them robust and durable. The differences can be seen in the lubrication. The 090 bearing is more dynamic, the 092 bearing requires less maintenance.
ttv tip: If you want to automate or minimise lubrication, the GETRO-092 CuSn8 sliding bushing is the better choice. If maximum surface distribution under high loads is required, we recommend the GETRO-090 CuSn8 sliding bushing with diamond-shaped pockets.
With CuSn8 sliding bushings, it is always important how well the lubricant is distributed between the sliding surface and the shaft. Lubrication pockets and lubrication holes reduce the actual contact surface and ensure that the grease or oil is not displaced immediately, but can spread evenly.
Depending on the geometry of the pockets or holes, the friction also changes:
For the CuSn8 sliding bushing, this specifically means
ttv tip: For slow movements and medium loads, the GETRO-092 CuSn8 sliding bushing with lubrication holes offers the best balance between service life and maintenance requirements.
CuSn8 sliding bushings are not dry sliding bearings. They only work with low wear in the long term if there is a stable lubricating film between the shaft and the sliding surface. How often you need to relubricate depends on the type of application and the bearing type:
At a glance:
Important: With GETRO-092 CuSn8 bearings, make sure that the lubrication holes are completely filled during installation, as this is crucial for both its function and the lubrication range.
Important: Not only the CuSn8 sliding bushing itself must be temperature-resistant, but also the lubricant. If the grease outgasses or dries out at 180 °C, even the best bearing is useless.
This means that the expansion coefficient of the CuSn8 sliding bushing is 2 × 10-⁵ °C-¹. This means that the bearing expands measurably in the event of large temperature fluctuations. The clearance to the shaft must be designed in such a way that it neither jams nor becomes too large (especially with tight tolerances or rapid temperature changes).
ttv tip: If you are working at the upper limit, check the lubricant regularly - especially for continuous operation close to 200 °C.
Once the CuSn8 sliding bushing has been pressed in, the inside diameter changes due to the properties of the bore. In order to adjust the clearance correctly, you should use a shaft with tolerance zone e or f for H9 inner diameters. If an h-shaft is used instead, we recommend enlarging the housing bore from H7 to F7. Only then will the clearance between the bearing and shaft be correct.
This means for you in concrete terms:
ttv tip: After press-fitting, especially with soft housing materials, always measure the inside diameter, where tolerance deviations can quickly occur.
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