Spicer uni joints
The universal joint we will discuss today is the universal joint. Originally invented in the 1683 by Robert Hooke the Hooke joint became the universal joint when patented in 1905 by Clarence Spicer. The Spicer joint then with Spicer’s business partner Charles Dana turned into the current day Dana Holdings.
Spicer Uni joints design are broken into two different offerings
With 2 models both use needle bearing in the bearing cross, one is greaseable, the other is not as it is called a permanently greased.
The universal joint is all the same whether a friction bearing block and pin or a needle bearing type. The couplings are the same and have the same issues of maintenance and a lack of flexibility. This lack of flexibility added to the maintenance required to make the coupling continue to function due to the build up of heat and the grease or lubrication that is required to keep the universal joint functioning.
Spicer universal joints design while similar to Lovejoy Uni joints is broken into two different offerings, these couplings or universal joint regardless of type still are a 3 part design so contains bearing cross and two hubs or yokes.
The two include the Friction bearing and Needle bearing (the needle bearing model is the coupling that is the same as the Spicer Uni joint), they have two variations of the needle bearing coupling as well, the standard version or the premium which basically is a updated pre-greased bearing for longer life.
This comes at a increase in price and while this will increase the useful life of the bearing cross it too will need to be replaced as either the lubrication runs out or the bearings themselves just wear out and need replacement due to equipment failure or bearing failure
Greaseable universal joint
Greaseable universal joint is standard universal joint central cross kit.
Greaseable Advantages – By being able to grease a universal joint, this allows the internal bearings to run for a longer period before needing to be replaced.
Greaseable Disadvantages – The ability to grease the bearings in a universal joint is crucial to their performance and long term use, the bearings still need to be replaced due to wear and tear, friction and galling. The angle of use will also determine how often the central bearing cross will need to be replaced.
The cheaper Spicer Uni joints are greaseable but they are not recommended for any more than light duty and even then any regular usage will reduce the lifespan of the bearings considerably. The same can also be said if they are used at any angle exceeding 4°.
Greaseable universal joints include
5-443X, 5-554X (Dana 1200 Series)
Permanent greased universal joint
Permanently greased universal joints are a more expensive version of the greaseable u joint, the bearings are pre greased to last longer. That being said angle of use speed used and amount of torque applied all are contributing factors for how long these more expensive bearings last.
Pre-greased bearing Advantages – The advantages are two fold, an increase in angle of misalignment and an increase in speed of operation. These bearings mean the angle of misalignment can increase to 25 degrees with less heat and more importantly no real increase in vibration due to thrust washers and other components.
The maximum speed is 6000RPM with these bearings so the applications at this high end of the RPM rating may nullify the warranty or just mean increased bearing replacement. The improved components and better quality grease used in all means the bearings last far longer and dont require as much maintenance such as greasing and inspection to ensure the u joint wont fail.
The other advantage of using the needle bearings is that the joint itself is able to be used at a higher angle of misalignment due to the bearings allowing a great range of misalignment verses the greaseable design. This means both higher speed and larger angle of misalignment which makes it useable in far more industries and different applications.
Pre-greased Bearing Disadvantages – The disadvantages are also two fold with the improved performance also means increased maintenance and increased replacement of wear parts, being the bearings. With the bearings now included inside the coupling the increased speed increases the friction so these pre-greased bearings still have the same issue, expanding with the heat and seizing inside the race, thrust washer will tend to absorb more heat and take more of the increased torque .
This means that while the bearing is pre greased it will still tend to dry out with use and will need to be replaced eventually, this increases the overall cost of the coupling, even with the more expensive bearings as it still increases the maintenance costs and lowers the ROI of the couplings.
Another disadvantage with the inclusion of the pre-greased bearings is, while they improve the flexibility of the coupling they still wear out as the misalignment angle during use being used outside a 1-8°, so the bigger the angle of misalignment they are used at, especially when you add increased torque and increased speed.
Even with a thrust washer to absorb some of that torque and misalignment, the increased rate of wear the bearings encounter since the ball bearings are being forced against the side of the bearing cage.
This force wears the bearing cage so the more force applied (ie bigger misalignment angle and increased torque) means the bearings wear the race as the balls are pushed out into the sides of the bearings making the race wider and wider allowing the balls to get loose until they can get forced out of the bearings cage.
Pre-greased universal joints include
5-443X (Dana 1200 Series)
How does Twin Spring Coupling differ from the Spicer Uni Joints
The Twin Spring Coupling has a number of advantages over the typical universal joint
No bearings so no greasing or replacing worn bearings, this means either greaseable or pre greased.
Twin torsion spring design means increased flexibility with increased torque, the largest is capable of 500ft lbs.
One central ball acts as the pivot point for the coupling, one ball means annual greasing, increasing ROI of the coupling over its lifespan.
One piece design means input and output hubs are integrated into the coupling making it a one piece design verses a three piece design with a universal joint, means no broken or cracked hubs and the one piece takes the vibration out of the coupling.
Spring design allow absorption of vibration and shock into coils reducing the vibration through the drivetrain and into the chassis
The combination of the twin spring design means similar flexibility to a universal joint but without the internal bearings means it produced less heat but can still be ran at both low and high speeds means the best of the universal joint (high torque, high flexibility, low cost) but without the downsides of bearings and hubs.
Available in all the same bore sizes, keyway sizes as well as the most common shaft sizes means it is a simple replacement for either of these two universal joints with the only difference being is the Twin Spring Coupling is slightly longer.
This is because of the increased flexibility and the thickness of the torsion spring coils to account for the torque requirements of the machinery.
Can be used in steering, axle, or driveshaft (3 different models means 3 different options
Allows for both angular as well as parallel misalignment
Inline shear pins means maximum exceeded torque will shear pins stopping any damage to the components that it is connected to
Time to improve on a 350 year design
Twin Spring Coupling when 1 is better than 3
For more information on our couplings go to this Universal Joint page