Stainless Steel Bushing, PTFE Fabric Sliding Layer

STANDARD SIZES Special sizes and materials are available on request

Stainless Steel Bushing bearing material is a self-lubricating, resin-impregnated hybrid cloth with PTFE fibers on the wear surface, bonded onto 316 stainless steel or Inconel 625 with special high-temperature adhesive. It has been developed for use as a low friction liner for valve stem bearings, particularly in high-temperature applications such as steam and process chemicals.

Self-lubricating bearings bushing are available in a range of shapes and sizes
bearings are low friction, self-lubricating, and have high load carrying capabilities. They are made up of a woven PTFE layer bonded to a metal support. The metal backing is chosen to be suitable for the application and is usually chosen from mild steel, zinc plated mild steel, stainless steel, Inconel, brass or bronze.

Applications Self-lubricating bearings are used to allow movement between mating surfaces in many different industries,

for example Valves: Self-lubricating bearings are used in all types of valves and are typically used for trunnion bearings and stem guides. Hydropower plants: Self-lubricating bearings are ideally suited for turbine guide vane assemblies and their actuators accomodating the high surface pressures involved. Agricultural machinery: In farm tractor kingpin, rocker shaft, and hitch assemblies. Crane and lifting equipment: Crane and hoist manufacturers use Self-lubricating bearings' ability to handle very high loads in boom foot pivots, and hinge and brace points in the mast pendant assembly which are inaccessible for grease lubrication. Self-lubricating bearings are completely self-lubricating and normally run dry, however, they can also be used where lubricating or other fluids are present. In dry operation, Self-lubricating bearings are recommended where low surface speeds are combined with high loads (see Technical Manual).

Features and Benefits

woven PTFE layer bearings: Are self-lubricating and operate without external lubrication. ? Are free from stick-slip, giving easy movement and operation. ? Are composite in nature and do not have the cold flow tendencies of solid and filled PTFE resins. ? Have high wear resistance giving long life. ? Can operate at temperatures beyond the range of most lubricants -50C to +150C. ? Are corrosion-resistant so can be used with aggressive liquids such as seawater, gasoline, acids, detergent solutions, hydraulic oils, ammonium hydroxide, oils. ? Are strong and can carry loads up to 420 N/mm2 for stainless steel and Inconel. ? Have good dimensional stability and the capacity to be formed to close tolerances.

When bonded to steel. Materials retain the ability to form and to a large extent have a high load capacity.
It is composed of polytetrafluoroethylene composite, blanking copper mesh, and steel back. The material structure has the bearing characteristics of polytetrafluoroethylene compound base tape and the shaping ability of punching cut metal mesh.
Bushing and pin shaft can be used with an interference fit to produce a wall thickness of 1 mm or thicker bearing, and at the same time achieve interference fit in the housing. Various methods can be used to protect the steel case from corrosion.
 
Availability
Standard PTFE packing is made of lubricating graphite, and other fillers may be added as required. The bushing style can be gasket type, straight sleeve type, flange type, and deep drawing type.
 
 Construction

woven PTFE layer bearing is a propriety self-lubricating bearing material of woven PTFE fibers applied to a rigid backing. To assure the best possible bond between the PTFE fibers and backing material, a secondary more readily bondable fibre is interwoven with the PTFE fibres so that is predominantly presented on the side of the bearing of the fabric.

woven PTFE layer bearings have the ability to resist PTFE cold flow under extremely high loads because the monofilament fibers have a tensile strength approximately 15 times greater than straight PTFE resins. Cold flow is also minimized by the effective entrapment of the fiber bundles by the high strength bonding resins.

woven PTFE layer bearings: The metal backing is chosen to be suitable for the application and is usually chosen from mild steel, zinc plated mild steel, stainless steel, Inconel, brass or bronze.

The PTFE fabric is embedded in artificial resin and securely bonded to the support body. The material will not expand and is chemically resistant to most media. It is especially suitable for oscillating motion, but can also be used for rotational or linear motion.
 
Stainless Steel Bushing, PTFE Fabric Sliding Layer can support heavy loads and dissipate heat well. The steel body allows easy and secure installation even at high temperatures or in light-metal housings. They have good sliding characteristics and a low coefficient of friction.

Typical problems that prompt the use of woven PTFE layer bushes bearings. 

1. Lubricant films are unable to be maintained.

2. Lubricants are unacceptable or undesirable because of contamination. 

3. Nonlubricating fluids are difficult to exclude from the bearing area.

4. High static impact loads are encountered.

5. Fretting corrosion occurs with conventional bearings. 

6. Freedom from stick-slip is a desirable feature.

7. Oscillating or sliding movements are involved. 

8. Conditions of high load with relatively low speeds are encountered. 

9. Corrosive substances are present. 

10. Unusual temperature conditions prevail. 

11. Distortion problems create misalignment. 

12. Maintenance cost reduction is important.

Stainless Steel with glued in PTFE fabric on the sliding layer, Maintenance-free

Technical Details​​

• Specific load capacity static≤420 [N/mm2]
• Specific load capacity dynamic≤180 [N/mm2]
• Sliding speed≤0,16 [m/s]
• Friction value0,03 [µ] to 0,07 [µ]
• Temperature strain-50 [°C] to +150 [°C] (shortly up to +180)

Material

• Support material Stainless Steel
• Sliding layer PTFE Fibre Fabric
• Standard stainless steel SS304, but other alloys are also available depending on the application

Tolerance Details

• Housing ØH7
• Bushing inner-Ø after mountingH8
• Shaft tolerance depending on the application

Shaft Material

 
Hardened steel, chrome-plated materials 45-50 HRC, surface finish <0.8 Ra
 

 

Properties

 
Stainless Steel Bushing, PTFE Fabric Sliding Layer has very good sliding abilities with a low friction value. No stick-slip effect and no moisture expansion. very good wear resistance.
 

Dry plain bearings consisting of a  stainless steel support body and a maintenance-free sliding layer

 
– The support body allows for easy handling and secure installation.
– The PTFE fabric is embedded in artificial resin and securely bonded to the support body. The adhesive bonding is resistant to moisture and will not expand.
– The load limit for Stainless Steel Bushing, PTFE Fabric Sliding Layer is determined by the strength of the support body and by the sliding layer
 

Suitable for a wide variety of applications, including:

– Plastic injection machines: elbow lever bearing support
– Cranes: articulating arm and cylinder bearing support
– Loaders: boom and cylinder bearing support
– Commercial vehicles: hydraulic platform bearing
– Textile and printing machines: conveyor chain bearing
– Passenger cars: transmission line, axle suspension
– Forklift: lift mast bearing support
– Rail traffic technology: coupling bearing
– Dams: supports for radial gates and flap gates
– Mining equipment: suspension bearing arrangement, traveling mechanism bearing, pivot bushings
– Environmental engineering: extension arm bearing, track roller bearing.
 

 
■ Are maintenance-free for life
(lubricant can reduce the service life)
■ Can be used in place of steel, bronze, and plastic bearings
(can support heavier loads than conventional plain bearings)
■ Suitable for bearing supports w/limited design space
■ Can support high alternating loads and swiveling motion
■ Especially suitable for bearing supports with limited design space
■ Are suitable for linear motion
■ Have a very low coefficient of friction
■ Have good damping characteristics
■ Easy to install: bearings are pressed into the housing bore and require no further axial location
 

Application Example

 
Loaders with pivot steering, also known as articulated loaders, are sturdy off-road transport vehicles that are often used in harsh environments. The steering principle makes them very maneuverable, and they can make precise movements in a very small space. A bucket is used to convey material. The movable bucket is connected to the guide linkage and the lift hydraulics by means of arms. Guide linkage and steering linkage are coupled to the front axle. The steering linkage transmits the motion of the steering wheel to the front axle. This allows the front wheels to be pivoted or aligned with respect to the rear axle. Bucket joints and steering joints must operate smoothly, and their unlimited agility must be guaranteed even after the loader has not been used for extended periods. The bearings allow only pivoting motion and are subject to very high shock loads. The bearing supports must be easy to install and maintenance-free.