Bushings vs. Bearings: What’s Right for Your Application?
What are Bearings?Bearings are multiple-component, precision-made machine parts that allow the rotating shafts of machinery to move at extremely high speeds, reducing friction between moving parts. A bearing’s primary function is to handle radial loading stresses and to support rotating shafts in machines, with secondary processes that include axial and shock loading.
Bearings allow interacting surfaces to roll, slide or glide over each other instead of grinding by transferring the weight of the load to the rolling elements, allowing the device to spin or slide. Since metal-on-metal contact is abrasive, causing metal degradation and continuous friction, bearings are proven to favorably reduce friction and premature wear.
Bearing TypesBearings can be divided into three classes: journal, linear, and thrust bearings. Within these categories, the bearings have the same basic structure and purpose. The main difference is the load they're handling and the type of rolling element used.
Bearing ApplicationsBearings are commonly used within the following applications:
- Vehicle wheels
- Steering mechanisms
- Suspension components
- Aircraft components
- Power turbines
- Manufacturing parts
What are Bushings?A bushing is a cylindrical component designed to support shaft loading that operates with sliding motion between the moving surfaces. Bushings are comprised of single-element components that may be composed of several different materials. Bushings are often used with heavier loads at slower speeds and can withstand substantial load transfer and shock loading.
- Bronze bushings
- Bi-metallic bushings
- Metal-polymer composite bushings
- Metallic Self-Lubricating bushings
- Plastic Bushings
Bushing ApplicationsBushings are primarily used for the following applications:
- Power transformers
- Suspension systems
- Dynamically loaded systems
- Drill jigs
- Hydraulic external gear pumps
What Separates Bushings and Bearings?Generally, bearings are distinguished from bushings by their multiple component designs, which include a cage containing the rolling elements (balls or rollers), the rolling elements, and an inner and outer race upon which the rolling elements interact.
- Motion is generally smoother than bushings, overcomes static friction by rolling instead of sliding
- Tighter tolerances for a better fit than bushings, reducing sloppiness and backlash
- More suited over bushings for high-velocity environments
- Provides extremely low friction motion that minimizes power consumption, noise, and wear on parts
- Easier to assemble than bearings and costs less
- Self-lubricating, providing quieter operation than most bearings
Bushings or Bearings: Which is Best for Your Project?The following factors should be considered before determining whether a bushing or bearing is suitable for your project:
- Velocity & Loading – For applications with high velocity, bearings provide an improved solution, while bushings react well to low-speed, heavy-load applications.
- Smoothness of Operation – Bearings do not stick or slip, unlike bushings, making them the correct choice for smoother operation.
- Maintenance & Lubrication – Bushings are ideal for maintenance-free, self-lubricating applications.
- Operating Noise – For critical noise applications, bushings provide less noise than bearings.
- Budget – Up to ten times less expensive, bushings offer a cost-friendlier option than bearings.