Precision Spacing Shim Manufacturing

The Critical Role of Precision Spacing Shims in Managing Bearing Preload

In the world of mechanical engineering, particularly in applications where precision and durability are paramount, the concept of bearing preload is vital. Bearing preload refers to the axial or radial load applied to a bearing that eliminates internal clearances, ensuring that the rolling elements (balls or rollers) are in constant contact with the raceways.

This preload is crucial for minimizing play, reducing noise, improving stiffness, and extending bearing life. One of the most effective and commonly used methods to achieve the correct bearing preload is through the use of precision spacing shims.

In this article the precision spacing shim manufacturing experts at Northern Industrial in the Detroit area delve into the intricate details of how shims contribute to bearing preload, exploring their design, application, and significance across various industries.

Understanding Bearing Preload

Bearing preload is utilized in mechanical engineering to:

Eliminate Clearance: Preventing axial or radial movement within the bearing, which could lead to vibration or noise.

Increase Rigidity: Enhancing the stiffness of the bearing assembly, which is critical for precision applications like machine tools or automotive steering systems.

Distribute Load: Ensuring even load distribution across all rolling elements, which is especially important in high-speed or high-load scenarios.

Extend Life: By reducing the micro-movements that cause wear, preload can significantly extend the service life of bearings.

The Role of Precision Spacing Shims in Bearing Preload

Precision spacing shims, which are thin, often circular pieces of metal or other materials, serve several key functions in managing bearing preload:

Precision spacing shims can be used to adjust the spacing between bearing components to achieve the desired preload. This precision is crucial since even a small discrepancy in thickness can lead to too much or too little preload, affecting performance.

Customization of precision spacing shims also allow for fine-tuning of preload in applications where standard bearing configurations do not meet the specific needs of the machinery or environment.

Additionally, over time, bearings might wear down, altering the preload. Precision spacing shims can be added or removed during maintenance to recalibrate the preload without replacing the entire bearing assembly. Precision spacing shims also offer versatility in that they can be made from various materials like steel, brass, or even non-metallic composites, chosen based on the operational environment, such as resistance to corrosion or need for electrical insulation.

Design and Material Considerations for Precision Spacing Shims

Material selection, shape and size are crucial considerations when manufacturing precision spacing shims. Below are the benefits of various precision spacing shims options.

Steel Shims: Commonly used for their strength in high-load applications. They offer durability but can be prone to rust if not treated.

Brass Shims: Preferred in environments where corrosion resistance is key or where electrical conductivity needs to be managed.

Plastic or Composite Shims: These are used in applications requiring non-conductive properties or where metal precision spacing shims might cause galvanic corrosion.

Thickness: Precision spacing shims are often available in a range of thicknesses, sometimes down to fractions of a millimeter, allowing for exact preload adjustments.

Shape and Size: Precision spacing shims can be flat, stepped, or even custom-shaped to fit around bearing components or within complex assemblies.

Applications of Precision Spacing Shims in Various Industries

Automotive Industry

Wheel bearings shims help in setting the correct preload to ensure the vehicle maintains its handling characteristics and tire wear patterns.

In engine applications, when used in timing gears or camshafts, shims adjust the preload on bearings, directly affecting engine performance and noise levels.

Aerospace

For aircraft bearings, precision is paramount. Precision spacing shims are used in landing gear, control surfaces, and engine components to manage preload, ensuring reliability under extreme conditions.

Machining and Manufacturing

In machine tools, the preload on spindle bearings must be exact to maintain precision over long periods of cutting or drilling operations.

Heavy Machinery

Construction equipment shims are vital in the bearings of hydraulic cylinders or drive mechanisms. Precision spacing shims can help manage the heavy loads and vibrations.

Wind Turbines

Gearbox and generator bearings precision spacing shims ensure that these bearings can handle both the rotational forces and the variable loads from changing wind conditions.

Installation & Adjustment of Precision Spacing Shims

Initial Setup: During assembly, precision spacing shims are often installed by trial and error, measuring the gap or torque to reach the desired preload.

Torque Method: In some applications, bearings are preloaded by tightening to a specific torque, with precision spacing shims adjusting the final position.

Feel Method: Experienced technicians might use a feel gauge or by “feel” to set preload, although this is less precise and more subjective.

Maintenance Adjustments: When bearings show signs of wear or when performance degrades, precision spacing shims can be adjusted to bring the preload back into specification without dismantling the entire setup.

Challenges of Precision Spacing Shims

Over-preloading occurs when too much preload increases friction, leading to overheating, reduced bearing life, and energy inefficiency. Conversely, under-preloading occurs when insufficient preload results in bearing play, leading to noise, vibration, and premature failure due to uneven load distribution.

When using precision spacing shims one must also consider the thermal environment; different expansion rates between shims and bearing components can alter preload as temperatures fluctuate. Additionally, corrosion in environments with moisture or chemicals, can be a concern. Selecting the right material for shims is crucial to prevent degradation affecting preload.

Economic & Performance Benefits of Precision Spacing Shims

Cost Efficiency: By allowing adjustments without replacing bearings, precision spacing shims can reduce maintenance costs and downtime.

Performance Optimization: Correct preload via precision spacing shims can enhance the machinery’s performance, from smoother operation to better fuel efficiency in vehicles.

Longevity: Proper bearing preload management through precision spacing shims can extend the operational life of equipment, impacting the total cost of ownership positively.

Environmental & Safety Considerations of Precision Spacing Shims

In large systems, like wind turbines or industrial machinery, correct preload can reduce energy consumption, contributing to environmental sustainability. And in automotive applications, the right preload ensures steering and braking systems work reliably, directly impacting road safety.

Precision spacing shims also play an indispensable role in managing bearing preload, affecting everything from the longevity of equipment to the performance and safety of vehicles. Their application across diverse industries underscores their importance in modern engineering. As technology evolves, so too will the methods of shim production and application, potentially leading to smarter, more adaptive solutions to bearing preload management.

Understanding and utilizing precision spacing shims correctly is crucial for anyone involved in the design, manufacture, or maintenance of machinery where precision and reliability are key. Precision spacing shims are not just small parts but significant contributors to the overall functionality and efficiency of mechanical systems.

Precision Spacing Shim Manufacturer

Northern Industrial Manufacturing is a premier manufacturer of precision spacing shims in the Detroit area. With a reputation for the closest tolerances, highest product quality, short lead times, process innovations, and technical prowess – we can meet your precision spacing shim manufacturing needs, while exceeding your expectations and delivering your parts on time and on budget.

Detroit Area Precision Spacing Shim Manufacturer: 586.468.2790