The terms "bearing bolt" and "friction bolt" refer to two different types of bolts used in construction and engineering, each serving distinct purposes and functioning differently. Here's a breakdown of the key differences between them:
Function: A bearing bolt, also known as a structural bolt or high-strength bolt, is primarily used to provide structural support and to transfer loads between connected structural elements. It is designed to withstand high loads and stresses, making it suitable for applications where structural integrity is critical.
Construction: Bearing bolts are typically made from high-strength materials such as carbon steel or alloy steel. They are engineered to have specific mechanical properties, including high tensile strength and shear strength, to ensure reliable performance under heavy loads.
Installation: Bearing bolts are installed using torque-controlled methods, such as torque wrenches or hydraulic torque equipment, to achieve precise tightening according to design specifications. Proper installation is crucial to ensure that the bolt can effectively transfer loads between connected members without failure.
Usage: Bearing bolts are commonly used in structural steel connections, such as column-to-beam connections, truss joints, and base plate connections. They are also used in bridge construction, industrial facilities, and other applications where high-strength fasteners are required to withstand substantial loads.
Function: A friction bolt, also known as a expansion bolt or wedge bolt, is primarily used for anchoring or fastening non-structural elements to concrete, masonry, or other solid surfaces. It relies on friction between the bolt and the surrounding material to provide anchorage and resist pull-out forces.
Construction: Friction bolts typically consist of a threaded bolt or rod with a tapered expansion sleeve or wedge nut at one end. When the bolt is tightened, the expansion sleeve or wedge nut is forced against the inner surface of the hole, creating friction and securing the bolt in place.
Installation: Friction bolts are installed by drilling a hole into the base material, inserting the bolt, and then tightening it using a wrench or impact driver. As the bolt is tightened, the expansion sleeve or wedge nut expands to grip the surrounding material, creating a secure anchor point.
Usage: Friction bolts are commonly used in construction, renovation, and maintenance projects to anchor fixtures, equipment, handrails, and other non-structural elements to concrete or masonry surfaces. They are also used in mining and tunneling applications for rock reinforcement and ground support.
In summary, the main difference between a bearing bolt and a friction bolt lies in their intended function, construction, and usage. Bearing bolts are used for structural connections and rely on high-strength materials and precise installation techniques to transfer loads between connected members. Friction bolts, on the other hand, are used for anchoring and fastening non-structural elements to solid surfaces, relying on friction to provide secure anchorage.
Definition: Bolts used to connect and fix bearing-related parts, such as the connecting bolts of the reducer's housing and cover and the connecting bolts of the bearing end cover.
Use: They tightly connect the bearing with other mechanical parts, ensuring that the bearing remains in a stable position during operation and can withstand certain axial and radial forces, allowing mechanical equipment to operate normally.
Definition: High-strength bolts that use friction resistance between the connected plates to transfer loads.
Use: Mainly used in steel structures requiring large load resistance, such as the connection of main components in building structures, to ensure the reliability and integrity of the connection.
Principle: Rely on the tightening force of the bolts to generate a preload between connected parts, fixing the bearing and other parts in a specific position.
Forces: During operation, the bolts mainly bear tension, shear force, and bending moments, ensuring the normal operation of the bearing and the stability of the mechanical structure.
Principle: A large preload is applied to generate friction between the connected plates. The external force is first borne by the friction; the plates only slip when the external force exceeds the friction.
Forces: The bolts themselves do not directly bear shear or tension unless the friction is insufficient to resist the external load.
Material: Usually selected based on specific use requirements and working environment. Common materials include ordinary carbon steel (e.g., Q235), medium carbon steel, or alloy steel for higher strength applications.
Strength Grades: Typically 4.4, 4.8, 5.6, and 8.8, depending on the bearing capacity required.
Material: Made from high-strength steel, such as 45 steel (8.8s), 20MnTiB (10.9S), etc.
Strength Grades: Commonly available in grades 8.8 and 10.9, with grade 10.9 being most common, providing higher preload and anti-slip capabilities.
Dimensions: Determined by the size of connected bearings and components, stress conditions, and other factors. They come in various diameters and lengths.
Accuracy: Typically based on standard bolt specifications. Higher precision may be required in certain applications but is generally less strict than for friction bolts.
Dimensions: Standard series like M16 - M30 are commonly used.
Accuracy: Requires high processing accuracy to ensure sufficient friction. The screw and screw hole tolerance can be up to 1.5-2.0mm to ensure proper load transfer and allow for some deformation.
Installation: Tightened with appropriate tools to ensure the specified preload is reached.
Removal: Relatively easy using the correct tools. However, long-term use or corrosion may make removal difficult.
Installation: Installed with special tools like torque wrenches to apply the correct preload, ensuring enough friction is generated.
Removal: Reuse is generally not allowed due to the plastic deformation during the initial installation, which affects the reliability of the connection.
