Single row tapered roller bearing is a rolling bearing that can simultaneously withstand radial and unidirectional axial loads. Its core working principle is based on rolling friction instead of sliding friction, and it achieves precise load distribution and stable operation through unique geometric design. The following is a detailed analysis of its working principle:
1. Structural composition and geometric characteristics
Core components
Inner ring (conical raceway): in conjunction with the shaft, the raceway is conical with a cone angle usually ranging from 10 ° to 30 °.
Outer ring (conical raceway): It matches with the bearing seat, and the raceway is symmetrical with the inner ring raceway, forming a V-shaped groove.
.Conical roller: It has a conical frustum shape, and the large end face of the roller is spherical, in contact with the cage;
; The small end face is flat and in contact with the inner ring edge.Retaining frame: usually made of steel or polyamide material, used to evenly separate rollers and prevent wear caused by mutual contact.
.Geometric Parameters
Contact angle (α): The angle between the normal of the contact point between the roller and the raceway and the bearing axis, usually ranging from 10 ° to 30 °.
. The larger the contact angle, the stronger the axial load-bearing capacity.Cone top coincidence: The cone tops of the inner ring, outer ring, and rollers are all located at the same point on the bearing axis, ensuring the concentration and stability of load transmission.
.2. Working principle: Rolling friction and load distribution
Rolling friction replaces sliding friction
When the bearing rotates, the tapered rollers roll between the tapered raceways of the inner and outer rings, converting the original sliding friction into rolling friction, reducing the friction coefficient to 0.001-0.003, significantly reducing energy loss and heat generation.
.Coordinated bearing of radial and axial loads
Radial load (Fr): acting in the vertical direction of the bearing, transmitted to the outer and inner rings through the contact point between the roller and the raceway.
. Load decomposition: The radial load is decomposed at the contact point into a component perpendicular to the raceway (normal force) and a component along the raceway direction (tangential force).Roller force: Normal force presses the roller against the raceway, while tangential force drives the roller to roll.
. Axial load (Fa): acting in the axial direction of the bearing, the axial force is converted into a radial component through the contact angle α, which is jointly borne by the roller and the raceway.Formula: The relationship between axial load and radial load is
F
a
=F
r
⋅ tan α, that is, the larger the contact angle, the greater the axial load that the bearing can withstand.
.Symmetric Load Distribution
The rollers of a single row tapered roller bearing are arranged symmetrically, and the cone angle design of the inner and outer raceway evenly distributes the load on all rollers, avoiding early failure caused by local overload.
.III. Key Design: The Role of Contact Angle and Preloading
Optimization of Contact Angle (α)
Small Contact Angle (10 °~15 °): Strong radial load-bearing capacity, suitable for heavy-duty radial load scenarios (such as machine tool spindles).
.Large contact angle (25 °~30 °): The axial load-bearing capacity is significantly improved, making it suitable for scenarios that require significant axial force (such as car differentials).
.Pre tightening mechanism
Axial pre tightening: By adjusting the axial position of the inner and outer rings, initial elastic deformation is generated between the roller and the raceway, eliminating internal clearance.
. Effect: Improve bearing stiffness, reduce vibration and noise; Prevent the roller from sliding (slipping phenomenon) under load; Extend the service life.Pre tightening method:
Positioning pre tightening: fix the axial position of the inner and outer rings (such as machine tool spindle) with nuts or washers.
.Constant pressure preload: Apply a constant axial force through a spring (such as a car transmission shaft).
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