DU Bushing

Ⅰ. Product Overview

DU bushing, also known as SF-1 self-lubricating composite bushing, is a three-layer composite oil-free self-lubricating sliding bearing. As a high-precision and maintenance-free mechanical transmission component, it differs from traditional copper bushings, bearing shells and oil-impregnated bushings, and serves as a core supporting part for lightweight and maintenance-free industrial equipment.

It is integrally formed by composite molding technology with three structurally layered designs that feature clear division of labor and complementary performances. The bottom layer is a high-strength low-carbon steel plate substrate, which provides stable structural support and compressive strength for the bushing and ensures mounting fitting accuracy. The middle layer is a porous bronze sintered layer with excellent thermal conductivity and structural toughness, which can bear pressure evenly, quickly export friction heat, and firmly bond the surface lubricating material. The surface layer is a 0.01-0.03mm thick mixed lubricating layer composed of PTFE (Polytetrafluoroethylene) and special additives, acting as the core functional layer for self-lubrication and low friction.

The core advantages of DU bushings are oil-free self-lubrication and zero daily maintenance. During operation, the surface PTFE material will form a uniform and stable solid transfer lubricating film on the mating shaft surface, completely eliminating shaft jamming and scratching. No lubricating oil or grease is required, making it perfectly suitable for mechanical equipment in scenarios where traditional lubrication is infeasible, maintenance space is limited, or working conditions are harsh. Widely used to replace traditional metal sliding bearings, it adapts to various linear, rotational and oscillating friction motion scenarios.

Ⅱ. Performance Characteristics

Benefiting from the unique three-layer composite structure, DU bushings balance structural strength and friction performance, delivering all-round performance advantages over ordinary copper bushings, plastic bushings and oil-impregnated bushings. The core performance characteristics are as follows:

1. Ultra-low Friction and Stable Operation Without Sticking

The friction coefficient is stably maintained between 0.04 and 0.12. The difference between static and dynamic friction coefficients is extremely small, completely eliminating the stick-slip phenomenon during mechanical movement and ensuring low-noise and stable equipment operation. The friction coefficient is even lower under light-load and high-speed working conditions, which effectively reduces mechanical transmission loss and improves equipment operation accuracy.

2. Ultra-high Load Capacity for Heavy-duty Conditions

Reinforced by the composite structure of the steel plate substrate and bronze intermediate layer, the standard static maximum bearing pressure reaches 250MPa. It can withstand long-term high loads, impact loads and alternating loads without structural deformation or cracking. Its load-bearing capacity is far superior to plastic bushings and ordinary oil-impregnated bushings of the same specification, meeting the operation requirements of heavy-duty industrial equipment.

3. Wide Temperature Resistance for Complex Thermal Environments

The applicable working temperature ranges from -40℃ to +280℃. It will not embrittle or crack at low temperatures and maintains stable sliding performance; no lubrication failure or material softening occurs at high temperatures. It supports continuous operation of equipment in extreme scenarios such as alpine environments, high-temperature metallurgy and drying equipment.

4. Maintenance-free and Long Service Life with Cost Reduction

Permanent lubrication is realized through a solid self-lubricating film, eliminating the need for regular grease refilling and complex lubrication systems, which greatly reduces labor and material costs for later maintenance. The wear loss during operation is minimal and will not scratch the mating shaft, effectively extending the service life of both bushings and supporting shaft parts, and reducing equipment downtime and maintenance frequency.

Ⅲ. Product Applications

With the comprehensive advantages of maintenance-free operation, low friction, heavy-load resistance and wide adaptability, DU bushings are widely used in automotive industry, general machinery, hydraulic equipment, aviation supporting facilities, engineering machinery and other fields, covering various friction motion components requiring low wear, high precision and low maintenance. The core application scenarios are listed below:

1. Automotive Industry

As core maintenance-free automotive components, DU bushings are commonly applied to the suspension systems, power steering mechanisms, door hinges, brake parts, transmission components and seat adjustment mechanisms of passenger and commercial vehicles. They effectively buffer vibration during driving, reduce component friction loss, improve overall vehicle operation stability, and require no post-installation lubrication maintenance, adapting to long-term outdoor service conditions of automobiles.

2. General Industrial Machinery

They are suitable for joints, slide rails, rotating shafts and swing arms of textile machinery, packaging machinery, printing machinery, woodworking machinery and automated assembly line equipment. The bushings solve common problems of traditional bushings such as easy sticking, frequent refueling and dust clogging, ensuring continuous, accurate and stable operation of automated equipment.

3. Hydraulic and Pneumatic Equipment

Widely used in hydraulic pumps, hydraulic valves, oil cylinders, air cylinders and pneumatic actuators of fluid transmission equipment. The low-friction property reduces hydraulic power loss and equipment heat generation, improves the transmission efficiency and response accuracy of hydraulic and pneumatic systems, and fits the closed and hard-to-maintain operating characteristics of fluid equipment.

4. Engineering and Mining Machinery

Applied to hinge support points, lifting mechanisms and swinging parts of excavators, loaders, cranes, mining machinery and construction machinery. They resist heavy-load impact, dust and oil erosion, maintain stable performance in harsh outdoor working conditions, and significantly reduce the failure rate and maintenance cost of engineering machinery.

Ⅳ. FAQ

Q1: Do DU bushings require lubrication? Can they operate under dry friction?

DU bushing is an oil-free self-lubricating bushing. No lubricating oil or grease is required under normal working conditions, and it can operate directly under dry friction. The surface PTFE solid lubricating layer can independently form a lubricating film to realize maintenance-free operation. Only under extreme working conditions of ultra-high speed and ultra-heavy load, a small amount of grease can be added for auxiliary cooling to further extend the service life; no additional lubrication is needed for conventional working conditions.

Q2: What are the core differences between DU bushings, ordinary copper bushings and oil-impregnated bushings?

The core differences lie in maintenance mode, friction performance and service life. Firstly, copper bushings have low hardness and high friction coefficient, require continuous oil lubrication, and are prone to wear and shaft scratching. Secondly, oil-impregnated bushings rely on oil storage, which easily causes oil leakage at high temperatures and failure under dry friction with high maintenance frequency. Thirdly, DU bushings feature self-lubrication and maintenance-free operation, lower friction coefficient, better wear and impact resistance, and no shaft damage. They adapt to wider working conditions with lower comprehensive operating costs, serving as an upgraded alternative to traditional bushings.

Q3: What is the applicable speed and load limit of DU bushings?

The static ultimate load of standard DU bushings is up to 250MPa, and the recommended continuous operating load is controlled within 100MPa to ensure long-term stable operation. They are suitable for low and medium-speed reciprocating swinging and rotational motion, and not applicable for long-term ultra-high-speed continuous operation. The speed adaptability meets the operating needs of most general industrial equipment.

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