Abstract:
A positive displacement lubrication system is disclosed that includes a rotatable shaft, a bearing, and a centrifugal force generating lubrication member that is mounted on the shaft for rotation with the shaft. The centrifugal force generator is spaced from the bearing member. A labyrinthine lubricant flow passage extends from the bearing, through a space between the bearing and the centrifugal force generating member, to the outlet member. Among other things, the system and method provides an efficient method of actively managing bearing lubrication and removal of lubricant, while also acting to seal off bearing areas from leaking. The positive displacement devices can be used for both grease and oil mist lubrication systems. They can also operate under heavy thrust loads when used to support the bearings.

Description:
[0001]     The present application claims priority under 35 U.S.C. 119 to U.S. Provisional Patent Application Ser. No. 60/596,098, to Daniel Lajiness, filed on Aug. 31, 2005, the entire disclosure of which is incorporated herein by reference. 
     
    
     BACKGROUND  
       [0002]     1. Field of the Invention  
         [0003]     The present application relates to lubrication of bearings and the like, and, in some preferred embodiments, to methods of positive displacement lubrication of motors or the like that require retention and removal of lubricant within a bearing and/or the like.  
         [0004]     2. Background Discussion  
         [0005]     Electric motors, and other devices, are often greased or lubricated at the time of manufacture. If a motor has been stored for a long period time (such as, e.g., six months or more), it is commonly lubricated prior to initiating use—such as, e.g., using a standard hand-held grease gun. Under some conditions, grease leakage can occur around a motor shaft hole or the like (such as, e.g., in the event of over-packing of grease).  
         [0006]     Lubrication of electric motors is also commonly performed as part of a planned maintenance program. Greasing and lubrication can often lead to accumulation of dirt and cleanliness problems. Accordingly, prior to greasing, one typically needs to be sure that fittings are free from dirt and that one always re-lubricates using grease that is also free from contamination. In some instances, motors may be equipped with an automatic grease relief fitting, a grease plug or a grease cover plate for the outlet. In some cases, it may be necessary to remove an automatic type relief fitting due to hardening of grease. Moreover, motors utilizing a grease plate may require the scraping out of old grease periodically.  
         [0007]     In summary, electronic motors and other devices having lubricated bearings and/or the like face complexities in maintaining desired lubrication levels and in maintaining cleanliness and operability of the devices.  
         [0008]     With respect to vertically-oriented bearing arrangements, such arrangements often experience significant problems in relation to maintaining proper lubrication levels within the bearing because gravity tends to act to pull the lubrication prematurely out of the bearing cavity. In addition, these vertical bearing arrangements also confront problems when seeking to remove used lubricant or to keep such lubricants from building up and/or clogging upon the bearings and/or leaking into areas other than the removal chamber.  
         [0009]     While a variety of lubrication systems and methods are known, there remains a need for improved systems and methods.  
       SUMMARY OF THE PREFERRED EMBODIMENTS  
       [0010]     The preferred embodiments of the present invention can significantly improve upon existing methods and/or apparatuses. Among other things, the preferred embodiments can provide an extended usable life of bearings that are subjected to loss of lubricant, in particular bearings whose loss of lubricant is exacerbated by gravitational flow of lubricant.  
         [0011]     A positive displacement lubrication system is disclosed that includes a rotatable shaft, a bearing, and a centrifugal force generating lubrication member that is mounted on the shaft for rotation with the shaft. The centrifugal force generator is spaced from the bearing member. A labyrinthine lubricant flow passage extends from the bearing, through a space between the bearing and the centrifugal force generating member, to said outlet member. Among other things, the system and method provides an efficient method of actively managing bearing lubrication and removal of lubricant, while also acting to seal off bearing areas from leaking. The positive displacement devices can be used for both grease and oil mist lubrication systems. They can also operate under heavy thrust loads when used to support the bearings.  
         [0012]     One aspect of the disclosure relates to a lubrication system that includes a positive displacement lubrication member that is mounted on a rotatable shaft for rotation with the shaft. The positive displacement member has paddles that apply a centrifugal force to lubricant that exists a bearing and travels through a labyrinthine lubricant flow passage from the bearing, towards the positive displacement lubrication member, and to a lubricant outlet, where it exits the system.  
         [0013]     Another aspect is the spacing of the positive displacement lubrication member from the bearing on the order of about 2 mm. The spacing can be modified to meet specific requirements of the system.  
         [0014]     In still another aspect of the disclosure a positive displacement lubrication member spaced from the bearing with a raised region adjacent to the shaft, and in contact with the bearing. The raised region provides a space between the bearing and the centrifugal force generator. The labyrinthine lubricant flow passage is formed by slightly spacing a centrifugal force generator from the bearing. The centrifugal force generator is spaced from the bearing a distance of about 2 mm. The lubrication device includes a seal member that is sealingly secured to the shaft and forms, in combination with the bearing a lubricant tight seal that restricts lubricant flow from the bearing to the shaft. The seal member has a longitudinally extending region that is in lubricant tight contact with the shaft. At least a portion of the seal member has a longitudinally extending region that is positioned between a paddle member and the shaft.  
         [0015]     The above and/or other aspects, features and/or advantages of various embodiments will be further appreciated in view of the following description in conjunction with the accompanying figures. Various embodiments can include and/or exclude different aspects, features and/or advantages where applicable. In addition, various embodiments can combine one or more aspect or feature of other embodiments where applicable. The descriptions of aspects, features and/or advantages of particular embodiments should not be construed as limiting other embodiments or the claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     The preferred embodiments of the present invention are shown by a way of example, and not limitation, in the accompanying figures, in which:  
         [0017]      FIG. 1A  is an end view of the obverse end of a positive displacement lubrication device;  
         [0018]      FIG. 1B  is an end view of the inverse end of positive displacement lubrication device of  FIG. 1A ;  
         [0019]      FIG. 1C  is a cross of the positive displacement lubrication device of  FIG. 1B , taken along line  1 C- 1 C;  
         [0020]      FIG. 1D  is a cross of the positive displacement lubrication device of  FIG. 1B , taken along line  1 D- 1 D;  
         [0021]      FIG. 1E  is a side view of the positive displacement lubrication device of  FIG. 1A ;  
         [0022]      FIG. 2A  is an end view of the obverse end of another type positive displacement lubrication device;  
         [0023]      FIG. 2B  is an end view of the inverse side of positive displacement lubrication device of  FIG. 2A ;  
         [0024]      FIG. 2C  is a cross sectional side view of positive displacement lubrication device of  FIG. 2B , taken along line  2 C- 2 C;  
         [0025]      FIG. 2D  is a cross sectional side view of positive displacement lubrication device of  FIG. 2B , taken along line  2 D- 2 D;  
         [0026]      FIG. 2E  is a side view of the positive displacement lubrication device of  FIG. 2A ;  
         [0027]      FIG. 3  is a cross-sectional view of a vertical motor from the drive end to the end opposite the drive end, and showing the positive displacement devices of  FIG. 1A  and  FIG. 2A ;  
         [0028]      FIG. 4  is an enlarged view of the end opposite the drive end of the vertical motor of  FIG. 3 ;  
         [0029]      FIG. 5  is an enlarged view of a portion of the section of the motor of  FIG. 4 ; and  
         [0030]      FIG. 6  is an enlarged view of the drive end of the motor of  FIG. 3 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0031]     While the present invention may be embodied in many different forms, a number of illustrative embodiments are described herein with the understanding that the present disclosure is to be considered as providing examples of the principles of the invention and that such examples are not intended to limit the invention to preferred embodiments described herein and/or illustrated herein.  
         [0032]     A first positive displacement lubrication device design, fits between a lower bearing face and the shaft shoulder  106 , as shown in  FIG. 5 . A second positive displacement lubrication device design performs the similar functions to the first, while being able to fit over a bearing locknut on the lower face of the bearing, as shown in  FIG. 6 . In some embodiments, a positive displacement lubrication device can be applied to vertical bearing arrangements, or horizontal bearing arrangements that have similar lubrication issues. The positive displacement lubrication device is preferably installed such that it spins in the same direction and at the same speed as the bearings. In the preferred embodiments, since the device spins with the bearings, the centrifugal force keeps the used lubrication moving outward and from backing up into the bearings.  
         [0033]     In the preferred embodiments, the device actively manages bearing lubrication and removal while also acting to seal off areas from leaking. It can preferably be used for both grease and oil mist lubrication systems. In addition, in some embodiments, it can also operate under heavy thrust loads when used to support the bearing(s). Other systems are forced to use thicker grease to help slow the removal of lubrication from the bearings by gravity. However, those greases are non-standard, may still not maintain proper lubrication levels in the bearing(s), and can have problems when used grease removal. Also, other sealing methods do not actively remove lubrication from the area to be sealed. The positive displacement lubrication device allows for these areas to be sealed without direct shaft contact which can reduce efficiency and which can damage the shaft.  
         [0034]     The preferred embodiments can be implemented in a variety of environments, such as, e.g., with various machinery that have bearings arranged with the rotating axis in the vertical plane and similar lubrication issues.  
       ILLUSTRATIVE EXAMPLES  
       [0035]     Looking now to  FIG. 1 (A-E), and  FIG. 2 (A-E), preferably, below and perpendicular to a surface of the positive displacement lubrication device are “paddles” or “tabs” that actively remove the used lubrication from the cavity below the bearings and project it into the outlet chamber. Preferably, also below and perpendicular to a surface of the positive displacement lubrication device, and concentric to the mounting bore, is a ring that has an outer diameter that is connected to the “tabs” and sized to stop the lubrication from being “pushed” into the shaft area and leaking into the motor.  
         [0036]     The positive displacement lubrication device is preferably sized such that there is a small clearance between the device and the surrounding parts, including bearings, such that lubrication flow is directed solely towards an outlet chamber. The flow of lubricant is impeded sufficiently to facilitate the maintenance of proper levels of lubricant within the bearings, while restricting lubricant build up and the consequent “choking” of the system. The combination of a small clearance along and a labyrinth path to the shaft area, effectively contribute to the prevention of lubricant from leaking into the motor.  
         [0037]     Now, looking to  FIGS. 3, 4 ,  5 , and  6  the positive displacement lubrication device described in this application employs a small gap below the bearing, to slow the rate of lubricant removal. The figures also show “paddles” that actively distribute the used lubricant to the outlet chamber, thus providing for ease of removal of lubricant. The device creates a tight, labyrinthine lubrication path that effectively seals off areas proximate a bearing while permitting flow to a removal chamber. A removal chamber is a region between a positive displacement lubrication (PDL) device, and a lubricant outlet.  
         [0038]     In some preferred embodiments, there are two configurations of positive displacement lubrication devices. The first type of PDL, indicated generally as  100 , in  FIGS. 1A , B, C, D and E, and as best seen in  FIG. 5 , fits between lower bearing face  511  of bearings  510  and shaft shoulder  513 . The other design, indicated generally as  200  in  FIGS. 2A , B, C, D and E, performs the same functions as PDL  100 , while being able to fit over a bearing locknut  522 . Locknut  522  is positioned at the lower face of the lower bearing  604 , as shown in  FIG. 6 , surface  206  of PDL  200 , and is in contact with snap ring  530 .  
         [0039]     As shown in  FIGS. 5 and 6 , PDL  100  can be, e.g., located at the end of the motor that houses fan  516 , and PDL  200  can be, e.g., located at the motor drive end.  
         [0040]     The positive displacement lubrication (PDL) device  100 , as shown in  FIG. 1  and the PDL  200 , as shown  FIG. 2 , can be applied to vertical bearing arrangements, and to horizontal bearing arrangements having similar lubrication issues, such as, e.g., gravity driven flow.  
         [0041]     The PDL devices  100  and  200  are installed such that they spin in the same direction and at the same speed as the shaft, and bearings  510  and  604 , respectively. As shown in  FIG. 1C , surface  112  of the positive lubrication device indicated generally as  100 , is parallel to and slightly offset form the bottom face of the bearing  510 .  
         [0042]     Similarly, surface  220  of the lubrication device indicated generally as  200  in  FIG. 2B , is parallel to and slightly offset from the bottom face of the bearing  604 . The slight offset between surface  220  of PDL  200 , and the bearing  604 , enables used lubricant to exit the bearing while impeding the discharge flow of lubricant sufficiently to enable lubricant levels to be maintained within the bearings for an extended period of time, thus extending the life of the bearing. Since the device spins with the bearings, the centrifugal force keeps the used lubricant moving outwardly, and from backing up into the bearings.  
         [0043]     Below and perpendicular to surface of the PDL devices  100  and  200 , are “paddles” or “tabs”  104  of  FIG. 1 , and  204  of  FIG. 2 . The tabs  104  are about 6.35 mm thick and about 19 mm in height and about 6.5 mm in width. The diameter of PDL  100  is about 95 mm. The diameter of PDL  100  is about 95 mm. The tabs  204  are about 6.35 mm thick, about 24 mm in height, and about 14.4 mm in width. The diameter of PDL  200  is about 125 mm. While one tab can be used, preferably two tabs are provided. A greater number of tabs can also be used. It is noted that dimensions specified herein can range about +/− 10% in some illustrative and non-limiting examples, and, in other embodiments, can range about +/−20%. In other illustrative and non-limiting examples, the dimensions of various parts can vary more substantially depending on circumstances.  
         [0044]     The paddles generate a centrifugal force that actively removes the used lubricant from the cavity below the bearings  510  and  604  and projects the lubricant into the lubricant outlet chambers  512  and  612 , respectively. Lubricant is delivered to bearing  510  through lubricant inlet  512 . Similarly, lubricant is delivered to bearing  604  through an inlet  608 . Sealing ring  110  is below, perpendicular to surface  106 , and concentric to the mounting bore  108 . Tabs  104  are connected to the outer surface of sealing ring  110 , which is sized to stop the lubricant from being “pushed” into the area of shaft  540  and leaking into the motor. Preferably, the tabs  104  of PDL  100 , and  204  of PDL  200 , advantageously, are formed integrally with their respective PDLs, but components can be assembled by welding or other bonding means. In the most preferred instances, PDL  100  and PDL  200 , are unitary, or integral devices.  
         [0045]      FIG. 4  shows additional fan end components such as canopy cap  714 , fan cover  712 , frame member  542 , stator  628  and rotor  528 .  
         [0046]     As shown in  FIG. 5 , PDL device  100  is sized such that there is a small clearance between the device and the surrounding parts, such that lubrication flow is directed solely towards the outlet chamber  512 , such that it impedes the flow of lubrication enough to help maintain the proper levels within the bearings  510 , but such that it does not allow lubricant to build up and “choke” the system. Preferably, the raised surface  102  of PDL  100  is in lubricant tight contact with bearing  510 , and, accordingly, the clearance between the PDL  100  and  510  is equal to the height difference between PDL  100  surface  112  and surface  102 . The term “lubricant tight contact” refers a contact between components that essentially prevents lubricant flow between the components. The term “lubricant tight contact” is not limited to absolute prevention of lubricant migration between components, but rather is inclusive of a very minimal lubricant migration between components. As noted above, the small clearance is preferably about 2 mm. The small clearance, along with the labyrinth path from bearing  510  to the shaft area, effectively blocks lubricant from leaking into the motor.  
         [0047]      FIG. 5  illustrates additional components of the end of the motor in which the fan  516  is housed, as for example, a bearing bracket  518  can be provided.  FIG. 5  additionally shows bearing locknut/lockwasher  522 . The bearing  510  is secured between bearing locknut/lockwasher  522  and raised surface  102  of PDL  100 . Felt strips  532  are provided between inner bearing cap  534  and shaft  542 .  
         [0048]     Preferably, tabs  104  and  204  are sized to stop the lubricant from being “pushed” into the area of shaft and leaking into the motor. The PDL devices  100  and  200  are sized such that there is a small clearance between the device and the surrounding parts, such that lubrication flow is directed solely towards the outlets  512  and  612 , respectively, and such that it impedes the flow of lubricant enough to help maintain the proper levels within the bearings  510  and  604 , respectively. The labyrinthine path and small clearance does not allow lubricant to build up and “choke” the system.  
         [0049]      FIG. 6  illustrates additional components of the motor drive end, indicated generally as  600  according to some illustrative embodiments. In this example, inner bearing cap  634  is positioned above bearing  604 , as illustrated in  FIG. 6  and p-flange member  640  is located at the outermost end of the drive end. A terminal box  624  is shown in part in  FIG. 4  and in part in  FIG. 6 . Lubrication inlet  608  provides lubricant to bearing  604  and outlet  612 , and provides an exit for spent lubricant. A felt strip  610  is provided between shaft  540  and a bearing bracket.  
         [0050]     The positive displacement lubrication devices  100  and  200 , actively manage bearing lubrication and removal of lubricant, while also acting to seal off bearing areas from leaking. Positive displacement devices can be used for both grease and oil mist lubrication systems. They can also operate under heavy thrust loads when used to support the bearings. Other systems are forced to use thicker greases to help slow the removal of lubrication from the bearings by gravity, but these greases are non-standard, may still not maintain proper lubrication levels in the bearings, and can have problems with used grease removal. Additionally, other sealing methods do not actively remove lubrication from the area to be sealed. In addition, the PDL devices enable the bearing areas to be sealed without a direct shaft contact that can reduce efficiency and damage the shaft.  
       BROAD SCOPE OF THE INVENTION  
       [0051]     While illustrative embodiments of the invention have been described herein, the present invention is not limited to the various preferred embodiments described herein, but includes any and all embodiments having equivalent elements, modifications, omissions, combinations (e.g., of aspects across various embodiments), adaptations and/or alterations as would be appreciated by those in the art based on the present disclosure. The limitations in the claims are to be interpreted broadly based on the language employed in the claims and not limited to examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive. For example, in the present disclosure, the term “preferably” is non-exclusive and means “preferably, but not limited to.” In this disclosure and during the prosecution of this application, means-plus-function or step-plus-function limitations will only be employed where for a specific claim limitation all of the following conditions are present in that limitation: a) “means for” or “step for” is expressly recited; b) a corresponding function is expressly recited; and c) structure, material or acts that support that structure are not recited. In this disclosure and during the prosecution of this application, the terminology “present invention” or “invention” may be used as a reference to one or more aspect within the present disclosure. The language present invention or invention should not be improperly interpreted as an identification of criticality, should not be improperly interpreted as applying across all aspects or embodiments (i.e., it should be understood that the present invention has a number of aspects and embodiments), and should not be improperly interpreted as limiting the scope of the application or claims. In this disclosure and during the prosecution of this application, the terminology “embodiment” can be used to describe any aspect, feature, process or step, any combination thereof, and/or any portion thereof, etc. In some examples, various embodiments may include overlapping features. In this disclosure, the following abbreviated terminology may be employed: “e.g.” which means “for example.” 
       GLOSSARY OF TERMS  
       [0000]    
       
         
           
               100  PDL type  1   
               102  surface of PDL type  1  for mounting flush to bearing inner ring face  
               104  paddle tabs  
               106  inner surface of PDL  100  for mounting flush to shaft shoulder  
               108  shaft mounting bore  
               110  sealing ring  
               112  surface of PDL  100  that is spaced from bearing  510   
               200  PDL type  2   
               202  surface of PDL  2  for mounting flush to the bearing locknut face  
               204  paddle tabs  
               206  inner surface mounts flush to bearing inner ring face  
               208  shaft mounting bore  
               210  sealing ring  
               220  surface of PDL  200  that mounts flush to bearing locknut face  
               222  surface of obverse side  
               224  surface of PDL  200  for mounting flush to snap ring support  630   
               508  lubrication inlet  
               510  bearings  
               512  lubrication outlet  
               516  fan  
               518  bearing bracket  
               522  bearing locknut/lockwasher  
               528  rotor  
               530  snap ring  
               532  felt strips  
               534  inner bearing cap  
               540  shaft  
               542  frame  
               602  paddle  
               604  bearing  
               608  lubrication inlet  
               628  stator  
               610  felt strip  
               612  lubrication outlet  
               624  terminal box  
               628  stator  
               634  inner bearing cap  
               640  P-flange bearing bracket  
               712  fan cover  
               714  canopy cap