Direct contact
Harald Nitzschke +49 (0) 7303 92874 - 0 nitzschke@ttv-gmbh.de
Sibro
Oil-soaked sintered bearings
Specializing in the production and manufacture of high-quality plain bearings, slide rails and special parts since 1983.
| Profil | Design | Base material | Load capacity | Temperature Range | Friction coefficient |
|---|---|---|---|---|---|
 |
SIBRO-FU-1 Sintered bronze | CuSn6Zn6Pb3 / CuSn10 | 35 N/mm2 | -80°C to +160°C | 0.12 - 0.18 |
 |
SIBRO-FU-2 Sintered iron | Fe | 45 N/mm2 | -80°C to +160°C | 0.15 - 0.20 |
|
SIBRO-FU-3 Sintered bronze steel | Fe + Cu + C | 45 N/mm2 | -80°C to +160°C | 0.12 - 0.20 |
The SIBRO-FU-1 sliding bushings made from sintered bronze powder are pressed to shape and sintered under a high pressure and temperature. The oil is simultaneously dispensed into the tiny pores on the metal.
The SIBRO-FU-1 sliding bushings can be used in dry conditions for applications with medium speeds and low loads over a long period of time without requiring any maintenance. Sintered bronze sliding bushings are economical options, and are available in an almost unlimited variety of dimensions. They are popular in electrical and electronic machinery, chemical engineering machinery, cars and office equipment.
Sintered bronze bushing SIBRO-FU-2
The SIBRO-FU-2 sintered iron sliding bearings protect the shafts by means of the embedded oil. At low loads, these bearings have the same sliding and frictional properties as the sintered bronze sliding bushings. . The absorbed oil in the sintered iron sliding bushings helps prevent seize-ups.
These bushings are commonly used in textile machinery, power tools and shock absorbers for cars and motor bikes. They can also be used statically as guide bushings or retaining bushings.
Sintered bronze bushing SIBRO-FU-3
The SIBRO-FU-3 sintered bronze steel sliding bushings have the same benefits as the SIBRO-FU-1 and SIBRO-FU-2 bushings.
The proportions of iron and bronze can be configured by the client according to different requirements.
Sintered bronze is the premium material among sintered bearings and offers impressive properties:
These properties make sintered bronze the ideal choice for demanding applications where operational reliability, durability and low noise levels are required.
Sintered iron offers an economical solution for less complex applications. It is particularly suitable where:
Thanks to its cost efficiency, sintered iron is ideal for series applications with stable operating conditions.
Conclusion: Both materials have their strengths - the right choice depends on the requirements of your application. We would be happy to advise you on selecting the optimum material for your plain bearing solution.
The structure of the material plays a decisive role in sintered plain bearings in particular. Thanks to their open-pored microstructure, these bearings have a pore volume of around 15-25 % of the total volume. These pores serve as storage chambers for liquid or solid lubricants, which are released independently onto the sliding surfaces - exactly when they are needed.
The lubricant stored in the pores is transported into the so-called bearing gap by the movement of the shaft. There - due to the slight eccentricity between the shaft and bearing - a wedge-shaped lubrication zone is formed. This geometry leads to a hydrodynamic effect: the lubricating film builds up automatically, without any external feed. The movement of the shaft is sufficient to distribute the lubricant continuously.
The result: a maintenance-free, durable and reliable bearing with excellent emergency running properties - ideal for demanding applications in industry, mechanical engineering or automation.
The centrepiece of a self-lubricating sintered plain bearing is its finely interconnected pore space. It accounts for around 15-25 % of the total volume and serves as a reservoir for liquid or solid lubricants. These are continuously released onto the sliding surface and keep the lubricating film stable even during long periods of operation - without any external lubricant supply.
As long as this lubricating film remains intact, there is no direct contact between the shaft and bearing - wear is therefore virtually eliminated. In practice, however, certain conditions such as high temperatures, vibrations, contamination or an uneven load can affect the service life. Oil losses due to evaporation, decomposition or leakage must also be taken into account in the design.
Special materials are used for more demanding environments: sintered bronzes containing MoS₂, for example, are designed for continuous operation up to 300 °C (even up to 400 °C for short periods) and offer a high level of operational reliability even under extreme conditions.
Conclusion: Sintered plain bearings are durable, maintenance-free and highly resilient design elements. The right design, the right material and a lubrication strategy tailored to the application form the basis for maximum service life - even under difficult conditions.
Recommended materials for shafts and journals
High-strength steels with a tensile strength of at least 600 N/mm² and hardened steels from 55 HRC are ideal. Under certain operating conditions, unhardened, stainless, chrome-plated or nickel-plated materials can also be used. However, caution is advised with galvanised surfaces: Excessively smooth or non-adhesive coatings - as with galvanised shafts - can hinder lubricant distribution or clog the pore structure of the bearing
Surface quality - the key to longevity
The lubricating film on sintered plain bearings is particularly thin. This makes a finely machined shaft surface with a roughness of Ra ≤ 0.8 µm all the more important. Smooth and load-bearing surfaces can be achieved using processes such as superfinishing, lapping, roller burnishing or vibratory grinding. A surface that is too rough or irregular, on the other hand, can damage the bearing and significantly impair its self-lubricating properties.
Corrosion protection and special environments
In humid or aggressive environments, we recommend hard chrome-plated shafts or alternatively stainless materials - supplemented by molybdenum disulphide coatings or chrome-plating to further improve the sliding properties. Roller burnishing or hard chrome plating of the surface is particularly useful for stainless steels in order to minimise the abrasive effect of nickel.
Geometry - precise shape instead of compromise
Not only the surface, but also the shape of the shaft is crucial. Major deviations from the ideal circular or cylindrical shape can lead to pumping effects that cause oil loss and noise. We therefore recommend keeping shape tolerances as low as possible.
For dusty or contaminated areas of application, the bearing point should also be protected by axial seals to prevent the ingress of particles and to ensure long-term functional reliability.
Oil-impregnated bearings: 0.05 - 0.10
Dry lubricated bearings: 0.15 - 0.25
A lower friction coefficient for oil-impregnated bearings can be achieved by low load and high sliding speed.
Professional press-fitting for precise results
We recommend the use of a press-fit mandrel to ensure the dimensional accuracy and surface quality of the bearings in the long term. This should be at least three times as long as the bearing itself and should be hardened and ground. Ground and lapped carbide mandrels are particularly suitable for series mounting.
Alternative mounting methods for special applications
In addition to classic press-fitting, there are also other mounting techniques available depending on the requirements, including
These methods are particularly suitable for special materials or operating conditions - we will be happy to advise you on the selection of the optimum solution.
Conclusion: Whether standard or customised - our sintered plain bearings impress with maximum precision, simple assembly and economic scalability.
Important for storage
Avoid storage conditions in which the oil can escape - for example by placing it on absorbent materials such as wood, paper or cardboard. These extract oil from the bearing, which can lead to a loss of function in the long term.
Our recommendation
Leave the bearings in the original plastic packaging until installation. These not only protect against oil loss, but also reliably protect against dust, dirt and other contaminants that could impair operation.
However, if oil leaks do occur, the bearings must be re-impregnated. This is because heat build-up can only be prevented and a long service life of the bearing guaranteed if there is sufficient lubricant.
SIBRO sintered bearings are impregnated at the factory with approx. 25 % oil by volume. The oil sits in the open pores of the sintered metal and thus ensures automatic lubrication: Friction during operation increases the temperature and pressure in the sintered bearing, forcing the oil out of the pores towards the sliding surface. As soon as the movement stops, the oil is then drawn back into the sintered bearing (capillary effect).
Prerequisites:
In special cases - e.g. with vacuum, very high speeds, a high continuous thermal load or aggressive media - it may make sense to additionally lubricate the sintered bearing or to switch to a variant with solid lubricant (e.g. MoS₂).
For typical applications such as:
factory lubrication is usually sufficient. Once the sintered bearing has been correctly installed, it runs maintenance-free and without relubrication.
You can do little wrong with plain bearings made of sintered bronze (FU-1): they have good sliding properties, are maintenance-free and economical. This is sufficient for many applications - especially for medium loads and clean running.
Plain bearings made of sintered iron (FU-2) are of interest when
- the bearing point is subject to high mechanical loads
- a high load capacity is required and the running does not have to be extremely fine
- the sintered bearing is used, for example, in power tools, shock absorbers or machines with constant vibration.
Bearings made of sintered bronze steel (FU-3) make sense when you need both:
The advantage of FU-3 is that you can have the ratio of iron, bronze and carbon adjusted to your application. This is particularly worthwhile for series applications or extreme operating conditions.
Summarized for you at a glance:
If you are not sure, a look at the speed, load and environment is usually enough. Or you can give us the application data and we will tell you which type suits your application.Kontakt
At TTV, SIBRO is the product name for oil-impregnated sintered bearings. However, these are the same materials, the same manufacturing processes and the same type designations as in the catalog:
SIBRO bearings are designed for temperatures up to 160 °C in continuous operation. The limit value is not a rough guide value, it is technically justified: The oil in the pores begins to evaporate or chemically decompose at approx. 160 °C. Once this happens, the automatic lubrication system no longer works.
This has two direct consequences:
This means that the bearing can still hold up mechanically for a while, but wear increases exponentially. In practice, you often only notice this when the shaft is already damaged or bearing parts have run in.
For higher temperatures (above 160 °C), you therefore need either
This is not necessary for typical applications in mechanical engineering, automotive engineering or the textile industry, where the temperature usually remains well below the critical temperature of 160° Celsius.
In principle, SIBRO bearings can also be mounted in plastic, aluminum or other non-ferrous materials. But not after impregnation. The oil in the pores would escape when pressed in, would not be compatible with the material or would interfere with the connection during bonding.
This is the correct procedure:
By the way: If you machine the bearing, e.g. calibrate, turn or coat it, you must follow the same procedure: first machine, then oil.
Plain bearings made of sintered bronze and sintered iron are maintenance-free, oil-impregnated and robust. This makes them ideal for machines where downtime is expensive or a lubrication point is difficult or impossible to access.
Sintered bearings are often used here:
Not sure which plain bearing is right for your application?
Tell us what the plain bearing needs to do. And we'll tell you what works for you.
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