Thrust roller bearings are axial load-bearing components with rollers (cylindrical, conical or spherical rollers) as rolling elements. Their core function is to bear unidirectional or bidirectional axial loads, while also taking into account a small amount of radial loads. Their structure consists of a shaft ring (matched with the shaft), a seat ring (matched with the base), rollers and a cage. They are divided into unidirectional (single-row rollers) and bidirectional (double-row rollers). Some types achieve self-alignment through roller shape or raceway design to compensate for installation errors or shaft deformation.
Compared with thrust ball bearings, the line contact of the rollers increases their axial load capacity by 3-5 times, making them suitable for low-speed and heavy-load conditions (speed <1500rpm).
2. Types of Thrust Roller Bearings
(1)Cylindrical Roller Thrust Bearings
The thrust cylindrical roller bearing's rolling element is a cylindrical roller with a straight or slightly convex end face. Its axial load capacity is the highest compared to the other two thrust roller bearings (long contact line, linear contact load distribution); however, it can only carry unidirectional axial force, cannot be adjusted, and has a low limit speed. The thrust cylindrical roller bearing is suitable for low-speed and heavy-load conditions (such as crane hooks and stamping machines).
(2)Spherical Roller Thrust Bearings
The thrust spherical roller bearing's rolling element is a drum roller (symmetrical or asymmetrical), the outer ring raceway is a spherical surface. The self-aligning function allows the axis to deflect ≤ 2°, and compensates for installation errors or shaft bending. It is suitable for working conditions with heavy loads, vibrations and poor axis alignment (such as metallurgical rolling mills, ship propellers, etc.).
(3)Tapered Roller Thrust Bearings
The thrust tapered roller bearing's rolling element is a tapered roller, and the roller axis and the bearing axis form a certain inclination angle (contact angle), which can carry axial force and part of the radial force at the same time. Thrust tapered roller bearings optimize load distribution by adjusting the roller inclination; but they need to be used in pairs or with radial bearings, and are suitable for composite load scenarios (such as gearboxes, rolling mills, etc.).
3. Thrust Roller Bearing Characteristics
(1)High axial load capacity: The thrust roller bearings utilize a line contact heavy-duty design that is one of its core differentiating factors when compared to ball bearings. A cylindrical/conical/spherical roller (non-point contact) is used as a rolling element, and the axial load capacity is 3-5 times that of thrust ball bearings of the same size.
(2)Strong constraints on friction and speed: The rollers and raceways are in line contact with a larger friction coefficient than those of thrust roller bearings; normal speed is <1500rpm, while at heavy loads much heat will be generated, which requires forced lubrication.
(3)Adaptable to slow speeds and heavy loads: With the relatively large inertia of the rollers and high friction resistance, they are preferred for intermediate and low speed applications (normally the order of their speed arbitrates from tens to hundreds of revolutions per minute).
(4)Withstand shock loads and vibrations: The high rigidity in the contact between the rollers and the raceways can accommodate heavy load shock impacts (such as stamping machines, mining machinery).
4. Thrust Roller Bearings Application
Thrust roller bearings are mainly used to bear axial load, widely used in heavy load, high speed, shock load larger working conditions. The following are common application scenarios:
(1)Heavy industry and metallurgical equipment: Metallurgical rolling mills, mining crushers, continuous casting machines, molten steel continuous casting equipment, etc.
(2)Energy and power equipment: Such as wind turbine variable pitch systems, turbine thrusters, steam turbines, gas turbines, etc.
(3)Heavy engineering machinery and transportation: Such as shield machine cutter drive, ship propellers, marine gearboxes, railway locomotive axle boxes, etc.
(4)Mining and construction machinery: Such as crane hooks, mining conveyors, excavators, bulldozers, etc.
(5)Manufacturing and stamping equipment: Heavy stamping machine tools, gearbox axial positioning, extruder screw drive, etc.
