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What Is A Sleeve Bearing?
July 28th, 2022
If the phrase “simple but effective” was invented for a specific component, it would be the sleeve bearing. Why? Because a sleeve bearing facilitates linear or rotational movement between two parts.
They are also known as bushings, plain bearings or journal bearings. Unlike the rolling action of a ball bearing or roller bearing, the sleeve bearing has a sliding action. When needed they can be used with lubricates or self-lubricating components to ensure smooth continuous operation.
With the addition of lubrication sleeve bearings offer a low coefficient of friction and provide excellent wear resistance. Because they are relatively low cost and maintenance-free, sleeve bearings are used in many applications.
What is the difference between a sleeve bearing and a bushing?
In a word: nothing. A bushing is a tube or sleeve that permits linear or rotational movement, which is exactly what a sleeve bearing is. The terms can be used interchangeably.
Sleeve bearing, plain bearing, journal bearing and sliding bearing are bushings; the terms describe the style of bushing. As we explain in our blog, A Guide to Bearings and Bushings, a bushing is always a bearing but not all bearings are bushings.
What is the purpose of a sleeve bearing?
Simply, sleeve bearings facilitate motion between two components, reduce friction and absorb vibration. They have a high load capacity, making them suitable for a range of heavy-duty applications.
Robust sleeve bearings can deal with high loads and high temperatures with incredibly low wear. Their contact area has high shock load resistance and they can compensate for misalignment of the other components.
They offer a number of advantages; low-friction, compact, reducing the size of the system, lightweight, easy to install and help remove vibration (and therefore noise).
Where are sleeve bearings used?
Sleeve bearings are incredibly versatile and can be used in a wealth of applications. They can be used to facilitate different groups of movement:
- Rotational movements
- Linear movements
- High frequency oscillating movements
They are commonly found in pivot points, and as a result they are used extensively in the automotive industry, manufacturing machinery and white goods. In the automotive industry they deliver rotational linear movement for hinges, seat adjustment mechanisms and steering yokes. Belt tensioners use sleeve bearings for high frequency oscillating movement. In manufacturing lift and tilt devices need them to facilitate linear movement, another example is clevis joints for hydraulic cylinder pins.
Types of sleeve bearing designs and materials
There are a few basic types of sleeve bearing and a range of material options that can be used. All sleeve bearings are a one-piece design with the most common type being the flanged sleeve bearing. A flanged sleeve bearing can take axial and radial loads. Alternative options include cylindrical and thrust washer designs. For higher side loads, a combination of a thrust washer and a cylindrical bearing is a good alternative. If the load is purely radial, go for a simple cylindrical bearing.
Bearings can be made from a range of materials. These include metal, bi-metal, ceramic, stone, graphite, composites and plastic. The function of the sleeve bearing is driven by the material choice as the material will determine the strength, elasticity, coefficient of friction and more.
Cast or sintered metal bushings have a low coefficient of friction under hydrodynamic conditions when used with hard steel shafts but the intense rattling rules out many applications. Moulded plastic is a low-cost option, and comes in a wide range of shapes and sizes; however, there are limitations to plastic bearings, as we discuss in our blog post, 5 Reasons to Replace Plastic Bushings.
NORGLIDE® Bearings are made from high performance plastic (PTFE), which is reinforced with metal and self-lubricating. PTFE dampens sound and vibrations, unlike all-metal bearings which can cause a high rattling noise.
Flanged Sleeve Bearing
Cylindrical Sleeve Bearing
Thrust Washer - can support
Self-lubricating sleeve bearings
For sleeve bearings to be self-lubricating a compound layer will need to be added. This ensures smooth operation and extends the bushing’s service life. External lubricant is sometimes beneficial in terms of wear and friction. Here additional grooves inside the surface can act as reservoirs for the lubricant.
NORGLIDE® Bearings don’t need external lubricants like grease or oil. This means they work reliably under robust operating conditions and a range of operating temperatures.
Benefits of NORGLIDE® Sleeve Bearings
There are a number of benefits to using NORGLIDE® Sleeve Bearings. The unique material structure and combinations allow our engineers to select the optimal material for the specific application. Further aspects can be fine-tuned too: a thick PTFE sliding layer for misalignment compensation, consistent coefficient of friction and reduced NVH. The choice of metal as a backing material offers high load capability and can be optimized for corrosion resistance if needed. We can tailor the electrical conductivity of the bearing’s sliding material by selecting the correct fillers and if space is a concern a thin wall design can be employed. The multitude of combinations available to NORGLIDE® engineers facilitate bearing designs to exacting requirements for each application. To find out more about the full benefits delivered by NORGLIDE® Bearings and the engineering challenges that can be overcome, read: Why NORGLIDE® Bushings and Bearings?
Talk to the bearings experts
If your application requires custom sleeve bearings, please talk to us at Saint-Gobain, engineer to engineer. We’re experts in developing, designing and manufacturing machined as well as moulded components for a range of applications and industries.
If you need any more technical information about sleeve bearings, please get in touch.