Patent Publication Number: US-2022213930-A1

Title: Split plummer block bearing housing

Description:
This application claims priority from German Application No. 102019207156.2 filed on 16 May 2019, the contents of which are to be taken as incorporated herein by this reference. 
     TECHNICAL FIELD 
     This invention relates to a split plummer block bearing housing for a rotatable shaft. The split plummer block bearing housing comprises a seal assembly. 
     BACKGROUND 
     Conveyor pulleys are used in various industries, for instance for conveyor belts in the mining industry. Conveyor pulleys, especially for heavy duty applications such as mining, are rotationally supported by bearings mounted in a housing. Conveyor pulleys are mounted in a system where many conveyor pulleys are supporting for instance a conveyor belt for transporting coal or iron ore in the mining industry. As such, the conveyor pulleys and the housings are exposed to a lot of contaminants that can cause bearing failure, thus service and change of the bearings is needed at times. Downtime in a transportation system to service, or even worse, to replace a bearing after an unplanned failure, is very costly. 
     An object of the invention is to further improve this. 
     SUMMARY OF THE INVENTION 
     The object is solved by the subject matter of claim  1 . Advantageous embodiments are described in the dependent claims. 
     It is also a cognition of this invention that there are solutions where seal assemblies are mounted on the side of the housing to reduce the amount of contaminants entering the housing and the bearing. The downside is that the housings become bigger in size and width, which means that the bearing is placed further away from the face of the pulley drum. With an increased distance between the bearing and the load carrying pulley drum, any given applied load, that increases the bending moments in the shaft, causes stresses, resulting in a need for larger and more expensive components for increased robustness to carry the load and bending stress. The solution according to the present invention extends the service life of pulley bearings, reduces the rate of bearing failures due to contamination, while remaining compact in size and width. Further, the invention also simplifies the process for changing bearings in-situ on conveyor, while avoiding failures of bearing due to poor installation 
     An object of the invention has been achieved by providing a split plummer block bearing housing for rotating shafts, such as a shaft for conveyor pulleys. The split plummer block bearing housing presents a detachable housing cap having at least one housing grease channel, and at least one seal assembly. The housing grease channel is made to transport grease through the housing cap into the interior part of the housing. The at least one seal assembly comprises a stationary part mounted on the housing and a rotating part intended to be mounted on a shaft. The stationary part has a seal grease channel intended to transport grease into the seal assembly. The stationary part and the rotating part further forms labyrinth shaped portions interacting to form a sealing effect in a non-contacting manner. The seal assembly further has sealing means putting the stationary part and the rotating part in physical contact with each other. The sealing means can be a flinger attached to either of the static or rotating part reaching towards and abutting the other part. The at least one seal assembly is mounted in a recess on the axial side of the housing so that the housing grease channel and the seal grease channel connects through a channel connection point. By providing this split plummer block bearing housing, grease can easily be filled from the outside into the seal assembly, increasing the lubricating properties and the sealing effect by the grease, thus increasing service life. At the same time, as the grease channels connect with each other from the housing cap, the grease refilling is not only easily accessible from the top of the housing, but by having the grease channel from the top of the housing cap and not separately on the seal assembly directly, the width of the split plummer block bearing housing can be reduced, meaning the bearing can be positioned closer to the loaded point of the shaft, for instance closer to the end phase of a conveyor pulley, this in turn reducing the bending forces and stresses in the bearing created from forces acting on the shaft. 
     The housing cap is made in one piece, i.e. an attached seal assembly to the housing cap is not to be interpreted as a housing cap. By being detachable, the housing cap can be both fixed and detached using for instance bolts. This is beneficial while servicing the bearing or changing the conveyor pulley as it becomes easier to detach the shaft and bearing from the housing. The at least one housing grease channel is a channel to supply grease from the radial exterior side to the radial interior side of the housing. As an example, there can be a connection point for a grease gun at the radial top of the housing cap where it is easily accessible, where the grease is lead to the inside of the housing through the at least one housing grease channel. 
     The “radial direction” is a direction substantially perpendicular from the axial extension of the shaft, and the “radial exterior side” is the side furthest away from the shaft, and the “radial interior side” is the side closest to the shaft. The “radial top” is the radial exterior side furthest away from the shaft in a substantially opposite direction to the force of gravity. 
     The split plummer block bearing housing can have an asymmetrical body where the width is minimized at an inboard side, such that, together with the recessed seal design feature, the effective distance from the bearing assembly center-line to the face of the conveyor pulley drum is minimized. Further the housing body opening diameter can be maximized to enable insertion of a standard hydraulic nut, thereby facilitating installation and/or removal of the bearing itself whilst encapsulated in the housing body. 
     In an embodiment of the split plummer block bearing housing, the seal assembly&#39;s labyrinth shaped portions extend in a radial direction. This is beneficial for the housing to remain compact. 
     In an embodiment of the split plummer block bearing housing, the housing grease channel and the seal grease channel are directed in a substantially radial direction. This is beneficial to make the split plummer block bearing housing compact in width, and to make the grease channel short, robust and easy to fill with grease. This is further beneficial when manufacturing the housing and seal assembly, where it is possible to either drill or cast an uncomplicated grease channel. 
     The housing cap can have two housing grease channels leading grease to seal assemblies on both sides of the housing. 
     The housing cap can also have three housing grease channels leading grease to seal assemblies on both sides of the housing as well as into the bearing via a lubrication groove on the radial outer side of the outer ring, having bearing grease channels connecting the groove to the inside of the bearing. 
     The housing cap can as a further example have two housing grease channels leading grease to a seal assembly on one side of the housing and to the bearing. This can be relevant in the case where the pulley shaft is connected on one side of the housing only, leaving the other side completely sealed or capped as no rotation occurs. 
     In a further example, the housing cap can have one housing grease channel leading grease only to a closed cavity at the outboard side of the housing and subsequently through the bearing in the axial direction and subsequently to the seal assembly at the inboard side of the housing. This can be relevant in the case where the pulley shaft is connected on one side of the housing only, leaving the other side completely sealed or capped as no rotation occurs. 
     In an embodiment of the split plummer block bearing housing, the channel connection point has sealing rings in between the seal assembly and housing cap, such as o-rings or quad rings. This is beneficial to prevent leakage of grease into other areas, thus reducing the amount of grease consumed and securing the effectiveness of the seal assembly by ensuring the grease is transported to the inside of the seal assembly and to the labyrinth shaped portions. 
     In a further embodiment of the split plummer block bearing housing, the seal assembly is un-split. This is beneficial to simplify handling, ensure proper sealing effect, and to prevent mounting errors. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Exemplifying embodiments will now be described more in detail with reference to accompanying drawings, wherein 
         FIG. 1  shows a cross section of a split plummer block bearing housing according to the invention. 
         FIG. 2  shows a cross section of a bearing mounted in a split plummer block bearing housing according to the invention. 
         FIG. 3  shows a cross section of a bearing mounted in a split plummer block bearing housing according to the invention. 
     
    
    
     DETAILED DESCTIPTION OF THE DRAWINGS 
       FIG. 1  shows a cross section of a split plummer block bearing housing  1  according to the invention. The split plummer block bearing housing  1  for conveyor pulleys has a detachable housing cap  2  having at least one housing grease channel  3 . An at least one seal assembly  4  comprises a stationary part  5  mounted on the housing  1  and a rotating part  6  intended to be mounted on a shaft  13 . The stationary part  5  has a seal grease channel  7 . The stationary part  5  and the rotating part  6  forms labyrinth shaped portions  8  and has sealing means  9  contacting each other. The at least one seal assembly  4  is mounted in a recess  10  on the axial side of the housing  1 . The housing grease channel  3  and the seal grease channel  7  connects through a channel connection point  11 . The housing grease channel  3  and the seal grease channel  7  are directed in a substantially radial direction. The channel connection point  11  has sealing rings  12  in between the seal assembly  4  and housing cap  2 , such as o-rings or quad rings. 
       FIG. 2  shows a cross section of a bearing  14  mounted in a split plummer block bearing housing  1  according to the invention. The split plummer block bearing housing  1  has sealing assemblies  4  on both sides and a third housing grease channel  3  connecting to the lubrication groove  15  in the radial outer side of the outer bearing ring, for further transportation to the bearing interior through the bearing grease channels  16 . The figure shows an SRB which is particularly beneficial in conveyor pulleys, but it could also be other bearing types more suitable to the application, such as CRB, TRB, Toroidal bearing, DGBB etc. The spherical roller bearing in the figure is sealed, which further enhances the sealing properties to reduce contaminants and debris entering the bearing. 
       FIG. 3  shows a cross section of a bearing  14  mounted in a split plummer block bearing housing  1  according to the invention, where one axial side of the split plummer block bearing housing  1  is sealed by an axial cap  18 . There is still a third inactive housing grease channel  3  portrayed in the figure leading down to the axial cap  18 , but it could of course also be taken away completely to reduce machining cost. 
     Although the present invention has been described according to a number of preferred embodiments, the examples given are not exhaustive. It will be appreciated by those skilled in the art that additions, deletions, modifications, and substitutions not specifically described herein may be made without departing from the invention as defined in the appended claims. 
     A reference herein to a patent document or any other matter identified as prior art, is not to be taken as an admission that the document or other matter was known or that the information it contains was part of the common general knowledge as at the priority date of any of the claims. 
     Where any or all of the terms “comprise”, “comprises”, “comprised” or “comprising” are used in this specification (including the claims) they are to be interpreted as specifying the presence of the stated features, integers, steps or components, but not precluding the presence of one or more other features, integers, steps or components. 
     LIST OF REFERENCE NUMBERS 
       1 . Split plummer block bearing housing 
       2 . Housing cap 
       3 . Housing grease channel 
       4 . Seal assembly 
       5 . Stationary part 
       6 . Rotating part 
       7 . Seal grease channel 
       8 . Labyrinth shaped portions 
       9 . Sealing means 
       10 . Recess 
       11 . Channel connection point 
       12 . Sealing ring 
       13 . Shaft 
       14 . Bearing 
       15 . Lubricating groove 
       16 . Bearing grease channels 
       17 . Bearing seal 
       18 . Axial cap