In the application of plastic bearing cages, Suzhou Wintone Engineering Plastics Wintone T31 is a special engineering plastic for heat-resistant creep, high load-bearing capacity and wear-resistant bearing cages, which can make your plastic bearing cages from low temperature below minus 40 degrees Celsius to high temperatures 200 degrees Celsius, and maintain the reliability of operation and work under long-term sustained high load conditions.

In the application of various plastic bearing cages, Suzhou Wintone Engineering Plastics Wintone T31 material can help you solve the following problems that traditional cage materials may encounter:

1. Glass fiber reinforced PA66 engineering plastics are prone to plastic deformation and failure when the bearing has a large temperature rise. When the temperature of the glass fiber reinforced nylon 66 cage exceeds 90 degrees Celsius, the bearing capacity drops rapidly, the wear resistance and fatigue life is insufficient, and the mechanical properties and dimensions are greatly affected by moisture.

2.PPS high-temperature plastics are relatively brittle, have insufficient vibration absorption, and are relatively noisy.

3.PA46 The water absorption rate of high-temperature plastics is relatively large, and the load-bearing capacity and size of the PA46 bearing cage are greatly affected by moisture.

4.PEEK high-temperature plastics have high cost pressure on some bearing cage applications.

The characteristics of Suzhou Wintone T31 material in the application of various plastic bearing cages are: excellent wear resistance and fatigue life, high mechanical strength and load-bearing capacity, high temperature creep resistance, low noise, excellent dimensional stability, and low moisture absorption.

What is the main function of the bearing cage?

The bearing cage can ensure the appropriate distance between the rolling elements and prevent them from contacting each other to reduce friction; it can evenly distribute the load force; guide and improve the rolling conditions of the bearing rolling elements to prevent damaging sliding phenomena.

The design and materials of the cage determine its performance and bearing reliability; it enables it to withstand stress caused by friction, strain and inertia forces and chemical corrosion from substances, solvents, etc. produced by lubrication or aging.

What are the types of bearing cages?

The types of bearing cages are usually divided into stamped cages, solid cages, and pillar cages.

1. The overall weight of the stamped cage is light and the internal space is large, which is conducive to the entry of lubricant;

2. The solid cage can allow higher rotation speeds. At high speeds, if the bearing needs to withstand other forms of motion, machined metal cages will also be used;

3. The pillar cage has a pin passing through the roller, and both ends of the pin are fixed to the washers. The overall lighter weight can accommodate more rollers and is usually used in oversized roller bearings.

What materials are commonly used for bearing cages?

The materials commonly used for cages include stamped steel, machined steel, brass, engineering plastics, etc. Different materials will also affect its performance.

1. Bearing cages made of stamped steel have higher strength, and their friction and wear resistance can be improved through surface treatment processes; cages made of machined steel are usually used in extra-large bearings or in environments that are not suitable for brass cages;

2. Stamped brass cages are common in some small and medium-sized bearings; machined brass cages are less affected by lubricants and can be cleaned with ordinary lubricants. However, it should be noted that the operating temperature of the brass cage does not exceed 250°C;

3. Cages made from polymers such as nylon 66 and nylon 46 have good toughness and resistance to friction, impact, acids and corrosion. However, bearing requirements have become more demanding and applications more specialized. Conventional cage materials such as nylon 66, nylon 46 and PPS no longer fully meet requirements in some applications. Some cage manufacturers therefore have to injection-mold certain cages from more expensive PEEK engineering plastic.

In recent years, the use of innovative engineering plastics in bearing cages has helped plastic cages achieve higher performance and greater reliability while controlling costs. For example, Wintone T31, a heat-creep-resistant and wear-resistant material from Suzhou Weiben Engineering Plastics, effectively addresses the difficulty that traditional glass-fiber-reinforced PA66, glass-fiber-reinforced PA46, and glass-fiber-reinforced PPS materials have faced over the past decade or so in simultaneously meeting requirements for noise reduction, high-temperature creep resistance, dimensional stability, and high load capacity in bearing cages. It also substantially reduces the manufacturing cost of PEEK bearing cages.

What are the guiding methods of bearing cages?

There are three main ways of guiding the bearing cage: rolling element guidance, inner ring guidance, and outer ring guidance.

1.Rolling element guidance

The standard structure generally uses rolling-element guidance. For example, in cylindrical roller bearings with short rollers, the rolling elements guide the cage, which contacts neither the inner-ring nor outer-ring flange surfaces and can be used universally. However, at high speeds, the increased rotational speed of the rolling elements makes their rotation unstable. Rolling-element guidance is therefore suitable for moderate speeds and loads, such as in gearbox bearings. A rolling-element-guided bearing cage is located around the middle of the rolling elements. The cage does not contact or collide with the bearing's inner or outer rings. Contact between the cage and rollers corrects roller motion and maintains the rollers at uniform intervals.

2.Outer ring guide

The outer ring is generally stationary, and outer-ring guidance makes it easier for lubricating oil to enter the guiding surface and raceways. High-speed gearboxes use oil-mist lubrication; guidance by the rotating inner ring would squeeze the oil away. In an outer-ring-guided bearing, the cage is positioned on the side of the rolling elements closest to the outer ring. During operation, the cage may contact the bearing outer ring and thereby correct its position. Outer-ring guidance is generally used under high-speed, steady-load conditions. Taking a cylindrical roller bearing as an example, it carries only an axial load of a fixed magnitude. The speed of each rolling element changes little during rotation, so cage rotation does not become unbalanced.

3.Inner circle guide

The inner ring is generally the rotating ring and supplies driving torque to the rolling elements. If the bearing load is unstable or light, slipping may occur. With an inner-ring-guided cage, an oil film forms on the cage guide surface. Film friction allows the inner ring to drag the cage in the unloaded zone, increasing the cage's supplementary driving torque on the rolling elements and helping prevent slip. The cage is positioned close to the inner ring. During operation, contact between the cage and inner ring may correct the cage's position.

The cage can distribute the inner ring, outer ring, and rolling elements evenly and orderly. A slight error can easily shorten the service life of the bearing or even damage it.

Suzhou Weiben Engineering Plastics mainly has two special engineering plastics for plastic bearing cages:

One is: Wintone T31, a special engineering plastic that is resistant to high temperature thermal creep, ultra-high load-bearing capacity, and high wear resistance for bearing cages;

Another product is Wintone ZG6, an engineering plastic specifically for bearing cages, offering corrosion resistance, low noise, high load capacity, low moisture absorption, and high wear resistance. It helps address the inadequate corrosion resistance of traditional glass-fiber-reinforced PA66, including resistance to acids, alkalis, salts, and hydrolysis. ZG6 also offers excellent vibration damping and wear resistance, effectively reducing bearing operating noise and significantly extending wear and fatigue life. Its water absorption is only one-sixth that of nylon 66, so moisture has little effect on its mechanical properties and dimensions, making cage accuracy and stability easier to control.

The application characteristics of Wintone ZG6 material in bearing cages are: high wear resistance, corrosion resistance, low noise and low moisture absorption.

What are the causes of bearing cage failure?

1, insufficient bearing lubrication

During the use of the bearing, lubricating oil or grease was not added in time, and the wrong type of lubricating oil or grease was used.

2, impact load on bearings

Severe vibrations in impact loads can cause collisions between rolling elements and cages. ‍

3, bearing cleanliness

If the bearing is not well sealed in the bearing box and dust enters, it will cause friction between the rolling elements and the cage, causing damage to the cage. ‍

4, installation issues

If the bearing is installed incorrectly, the cage will be damaged during installation. ‍

5, bearing creep phenomenon

Creep refers to the sliding phenomenon of multi-finger ferrules. When the interference of the mating surface is insufficient, the load point moves in the surrounding direction due to sliding, causing the ferrule to deviate in the circumferential direction relative to the axis or housing.

6, abnormal load on bearing cage

Improper installation, tilt, excessive interference, etc. can easily lead to reduced clearance, aggravated friction and heat generation, surface softening, and premature abnormal peeling. As the peeling expands, peeling foreign matter enters the pockets of the cage, causing the cage to run blocked and generate additional loads, which intensifies the wear of the cage. Such worsening circulation may cause the cage to break. ‍

7, bearing cage material defect

Cracks, large foreign metal inclusions, shrinkage cavities, bubbles and riveting defects, missing nails, pad nails or gaps on the joint surface of the two cage halves, severe riveting injuries, etc. may cause the cage to break. ‍

8, intrusion of hard foreign matter into the bearing

The intrusion of foreign hard foreign matter or other impurities aggravates the wear of the cage. If all the above reasons are solved, the life of the bearing will be very long. The reason why many bearings are damaged is not that the bearing itself has expired, but is caused by many external environments, such as insufficient lubrication, dust ingress, installation errors, excessive load, excessive temperature, coupling misalignment, etc. ‍

9, other reasons

Coupling misalignment causes bearing skew and uneven force; belt installation is too tight; environmental problems, etc. may damage the bearing or cage.

(Source: Suzhou Weiben Engineering Plastics Co., Ltd.)