www.bronzegleitlager.com professionally developed bearings can meet the special application requirements of the fluid power industry. Under the condition of high load and high speed, the BIMETAL BEARINGS solution is stable and reliable and supports most fluid power applications.

A Reliable, Lighter, Greaseless Bearing Solution

Viiplus Low-Friction Pump Bearing Solution

The aluminum bushing block serves several purposes, which include supporting the gear shafts, acting as a thrust bearing and providing a sealing function to ensure good contact with the faces of the gears. SICAL®3D alloy is highly effective under a wide range of load, speed, temperature and fluid viscosity conditions.

Sealing efficiency can be compromised under shaft loading due to internal leakage resulting from deformation and changes in geometry of the side face of the bushing block. The superior mechanical strength of SICAL®3D resists this deformation which significantly improves the volumetric efficiency of external gear pumps and motors.

Hydraulic applications:

Hydraulic pumps are used in hydraulic drive systems and can be hydrostatic or hydrodynamic. A hydraulic pump is a mechanical source of power that converts mechanical power into hydraulic energy (hydrostatic energy i.e. flow, pressure).

In the hydraulic market viiplus provides solutions for various applications.

The typical applications are:

• Piston pumps and motors
• Gear pumps and motors
• Vane Pumps
• Cylinders

Piston pumps and motors

The bushing blocks geometry plays the main role in the process of defining functional and
mechanical parameters related to the performance of the pump (high efficiency, low noise level,
assembly ability).

Other piston pump applications

viiplus bimetal bushes are composed of two metal strips, in two different materials; the first is normally in steel, the second is normally constituted by an alloy containing copper, which when coupled with the steel strip acts as an internal covering. Furthermore, some sizes also have an external relubrication hole.

Advantages

The special construction of these bushes means they have good resistance against wear, in particular at medium speed with a medium load, or at low speed with a high load.
 

Special Techincal Features

The internal surface of the viiplus bimetal bushes can include different types of channels, so as to satisfy the various types of applications and lubrication conditions in which the bushes may be used.

Gear pump applications

Gear pumps (with external teeth) (fixed displacement) are simple and economical pumps. The swept volume or displacement of gear pumps for hydraulics will be between about 1 to 200 millilitres. They have the lowest volumetric efficiency ({displaystyle eta _{v}approx 90%} eta_v approx 90 % ) of all three basic pump types (gear, vane and piston pumps).

PTFE lined self-lubricating bearing also called DU bushing, dry bushing, DU bearing, bushing,PTFE coated bearing,SF-1 oilless bearing,PTFE liner metal polymer composite bearing and PTFE based plain bearing. This type of DU bush takes PTFE layer as sliding layer which makes products can perform very well under dry condition or oil condition.

Material Structure

These materiais consist of metal backing bonded to a porous bronze sintered layer with PTFE based polymer bearing layer.The metal backing provides mechanical strength, while the bronze sinter layer provides a strong mechanical bonding between the backing and the bearing lining,the PTFE based polymer offers exceptional low friction even under dry condition.

Advantages

Improved energy efficiency with the low friction performance of PTFE-enriched overlay;
Extended service life with a high wear-resistant bronze layer;
Zero maintenance as self-lubricating bearings can operate dry without grease;
Greater reliability than bimetallic bearings by avoiding potential shaft/bearing seizure under boundary lubricated conditions and frequent stop/start operation;
Compact, lightweight designs with thin-wall bearing construction;
Reduced noise with no metal-to-metal contact between the bearing and the shaft;
Quick, simple assembly without expensive mounting tools.

Gear pump bearing block type

Shafts in gear pumps. A low operating bearing clearance is essential for the high build-up of pressure and for low gear-pump leakage. To ensure a fault-free hydrodynamic operating state, the plain bearings must exhibit a bearing clearance tailored to the operating medium. The plain bearings come into direct contact with the operating medium. Aggressive media may be used, depending
on the application. The plain bearings must therefore offer high resistance to abrasion, good resistance to erosion, chemical compatibility and low swelling tendency.

Advantage: Reliable function of the bearing with  plain bearings

Hydrodynamic operation
Sliding speed up to 10 m/s
High media compatibility
Low operating bearing clearance
High resistance to abrasion
High resistance to erosion
Good chemical resistance
Low swelling tendency
Low level of wear, even at high engine speeds and mixed friction

Pump Bearing Application Requirements

External gear pumps and motors mounted with hydraulic bushing blocks are widely used in many industries such as construction, agriculture, automotive and material handling equipment and chemicals.

Built with few components, these reliable, lightweight, robust pumps provide outstanding performance in volumetric efficiency. When assembled with low-friction bearings, they can provide fixed-flow efficiencies of greater than 95% to hydraulic systems.

Viiplus Pump Bearings - Benefits

Compared to standard aluminum alloys SICAL®3D offers:

High mechanical strength and when combined with high precision VIIPLUS machining, improved volumetric efficiency, especially in the medium pressure range
Low friction between the gear and the bushing block faces for reduced energy losses
Good bearing properties which, depending on the operating conditions, allow designs without metal-polymer bearings
High precision machining for reduced clearances and quiet operation

Vane Pumps

The vane rotor is supported by bearings at the front and back plates.

When mounted in the back plate, needle roller bearings can fail due to oil starvation, particularly after long periods of rest in different climatic conditions or during repeated stop-start operation.

To improve pump reliability, viiplus metal polymer cylindrical bearings underwent trials to determine the feasibility of replacing the needle roller bearings.

The rigorous, extensive testing program included operation at full pump power and different engine regimes from 500 to 7 000 rpm under boundary, mixed and hydrodynamic lubrication, stop/start operation and oil starvation.

The results of these tests confirmed that the metal polymer composite cylindrical bushings provide superior pump reliability thanks to their excellent tribological performance of under dry, marginal and hydrodynamic lubricated operating conditions.

Hydraulic cylinder applications

Viiplus provides high quality components with competitive prices.

We have years of experience with OEMs and Tier One suppliers to give them an innovative edge in the market. Viiplus engineer teams are here to help you to design the product you need at the lowest cost.

We have wide range of customer support including worldwide local supply and R&D.

Viiplus offers:

A wide variety of high performance bearings and solutions to give our customers an edge in the market.

Great customer support from Viiplus teams who provide technical support for any kind of bearing questions.
An incredible strategic partner with local support. We provide our customer with the right products that offer high quality at a lower cost. Worldwide network that makes on-site support anywhere in the world possible.