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Introduction to linear guide bearing seals
Sealing is critical to any linear guidance system with manufacturers offering a wide variety of sealing designs and materials to meet a vast range of environments and applications. Bearing seals for profiled recirculating linear guides serve two functions. Number one, to keep any contaminants out and number two, to keep the lubrication in.
Without a suitable sealing design, the linear system wouldn’t operate properly, with premature wear likely resulting in failure. Here we will look at CPC’s (Chieftek Precision Co) unique sealing and lubrication options, including the patented reinforcement plate design enabling the linear guides to achieve 10m/s, while also incorporating scraper functions for enhanced protection against contaminants.
The whole CPC range is available in the UK & Ireland through distributor and partner, Kiwi Motion.
Standard linear guide bearing seals
Most linear guide manufacturers offer the most basic seal of single or double lipped style. These seals make direct contact with the rail giving good protection against liquid and fine particles.
CPC recommends their standard ‘S’ seal. The ‘S’ bearing seals operate in direct contact with the rail surface, giving them increased dustproof and lubrication retention capabilities.
CPC recommends this class of seal for linear guides that operate in environments high in foreign particles, such as sawdust, for long periods of time.
When the application and environment demand extra sealing capabilities CPC has the answer through their patented stainless steel reinforcement plate design.
Not only does this innovative design allow the guides to operate at 10m/s, Amax >450m/s2, but the reinforcement plate also functions as a scraper for larger particulates like iron fillings and has no more than 0.3mm clearance between the plate and the rail. Total scraping of external objects above 0.3mm is realised.
An additional metal scraper used in conjunction with standard sealing options can also be added for maximum sealing characteristics. Low friction seals can also be used instead of the standard ‘S’ bearing seals and have an inbuilt scraper function. CPC low-friction seals have slight contact with the rail and are suitable for most environments and where the application demands low running torque and low force.
In a lot of cases, we typically think of just the front bearing seals located on each end of the linear guide. But most recirculating linear guides also include inner, bottom, and lateral (universal) seals. These prevent contamination from entering from below and along the sides of the linear carriage, becoming particularly useful when the assembly is mounted on its side, vertically or upside-down.
What comes as standard?
CPC linear guides are also supplied as standard with internal inner and bottom bearing seals acting as the last line of defence against contaminants that may pass the front seal or that may collect in or around the rail mounting holes. All sealing options are available from Kiwi Motion.
Some other linear systems can be operated without seals, such as round shaft linear bearings and cam rollers, although for most linear systems, profiled rail linear guides included, it is always recommended to have a suitable setup due their importance in keeping contaminants out and maintaining proper lubrication.
Sealing and lubrication
A proper bearing sealing system, including good quality bearing seals, will keep contaminants out. The second critical function is to keep lubrication in. Without proper lubrication the system will see premature wear and eventual failure. The CPC sealing options are vital as they act as protection for the ground-breaking internal lubrication system. CPC linear guides come complete with internal upper and lower lubrication storage pads.
Due to the internal nature of the pads, there is no need to add lubrication units to the end of the linear guide thus saving space, an important factor to consider for the machine builder. The PU embedded lubricant pads ensure full lubrication contact with the rolling ball bearings, particularly important for short stroke applications and in general to prolong the life of the linear guide.
The CPC design, due to the embedded pads absorption and retention capabilities, results in a product that features a long operation life and long-term lubrication.
CPC linear guides come as standard with a wide variety of grease nipples and oil piping joints for easy application.
There are also specialised grease guns and lubrication kits available which come with different types of nozzle adaptors for ease of use.
Kiwi Motion are distributors of CPC products for the UK & Ireland and supply the whole CPC linear range. All CAD models can be found on CPC’s part community.
