Lubricant pump and cone movement dampener

Abstract

A lubricant pump and cone movement dampener system for a rolling cone cutter of an earth-boring bit is disclosed. The system includes an axial bore passing through the end of journal pin. The axial bore is fitted with a unidirectional valve and is in fluid communication with the bit's lubricant and with a grease passage. Lubricant, such as a grease, is pumped through the grease passage in the cone cutter, where it passes through the valve, out of the bore, and into the journal gap formed by the interior of the cone cutter and the exterior of the journal pin. Axial movement of the cone caused by formation forces acting upon the cone cutter as it rotates in the borehole causes more lubricant to be drawn into the journal gap. When the cone moves axially back in the opposite direction, heated lubricant in the gap is expelled from the gap via holes within the ball race of the journal pin. The system cycles cooler grease through the gap, dampens axial cone movement and reduces damage to the journal seal.

1 . A cone movement dampener system for an earth-boring bit, comprising: 
 a journal pin having an outer surface including a first journal surface;    a cone disposed over said journal pin and having a second journal surface;    a journal gap formed between said first and second journal surfaces;    a grease passage in fluid communication with said journal gap;    a bore in said journal pin in fluid communication with said grease passage and extending through said outer surface of said journal pin; and    a unidirectional valve disposed within said bore, said valve adapted to open to allow lubricant movement out of said bore and to close to prevent lubricant movement into the bore.    
   
   
       2 . The system of  claim 1 , wherein said bore is formed through an end of said journal pin.  
   
   
       3 . The system of  claim 1 , wherein said journal pin includes a circumferential ball race in fluid communication with said grease passage.  
   
   
       4 . The system of  claim 1 , wherein said unidirectional valve is a ball valve.  
   
   
       5 . The system of  claim 4 , wherein said ball valve is spring biased.  
   
   
       6 . The system of  claim 1 , wherein said unidirectional valve opens when said cone moves away from said journal pin.  
   
   
       7 . The system of  claim 1 , wherein said unidirectional valve closes when said cone moves towards said journal pin.  
   
   
       8 . A cone movement dampener system for an earth-boring bit, comprising: 
 a journal pin having a base portion connected to a journal segment leg and having a first journal surface;    a cone disposed over said journal pin and having a second journal surface, said first and second journal surfaces forming a gap therebetween;    a lubricant disposed within said gap;    a seal between said first and second journal surfaces to maintain the presence of said lubricant within said gap;    an axial bore through the end of said journal pin; and    a unidirectional valve disposed within said axial bore for allowing movement of said lubricant out of the axial bore and into said gap.    
   
   
       9 . The system of  claim 8 , further comprising: 
 a circumferential ball race formed between said first and second journal surfaces; and    a grease passage in fluid communication with said ball race and passing through said journal pin.    
   
   
       10 . The system of  claim 8 , wherein said unidirectional valve is a ball valve.  
   
   
       11 . The system of  claim 10 , wherein said ball valve is spring biased.  
   
   
       12 . The system of  claim 8 , wherein said seal is an o-ring.  
   
   
       13 . The system of  claim 1 , wherein said unidirectional valve opens when said cone moves away from said journal pin.  
   
   
       14 . The system of  claim 1 , wherein said unidirectional valve closes when said cone moves towards said journal pin.  
   
   
       15 . A drill bit for drilling through earthen formations comprising: 
 a bit body having an extending journal pin;    a rolling cone cutter rotatably mounted on said journal pin, said cone cutter and said journal pin being coaxially aligned;    a passage in said journal pin in fluid communication with a gap between said journal pin and said cone cutter;    a bore in fluid communication with said passage and said gap; and    a unidirectional valve that allows fluid flow through said bore in a first direction and restricts fluid flow through said bore in a second direction that is opposite said first direction.    
   
   
       16 . The drill bit of  claim 15 , wherein said bore is formed through an end of said journal pin.  
   
   
       17 . The drill bit of  claim 15 , wherein said journal pin includes a circumferential ball race in fluid communication with said passage.  
   
   
       18 . The drill bit of  claim 15 , wherein said unidirectional valve is a ball valve.  
   
   
       19 . The drill bit of  claim 18 , wherein said ball valve is spring biased.  
   
   
       20 . The drill bit of  claim 15 , wherein said unidirectional valve opens when said cone moves axially away from said journal pin.  
   
   
       21 . The drill bit of  claim 15 , wherein said unidirectional valve closes when said cone moves axially towards said journal pin.  
   
   
       22 . The drill bit of  claim 21 , wherein said unidirectional valve closes to a fully-closed position and substantially prevents fluid flow through said bore in said second direction that is opposite said first direction.  
   
   
       23 . A method of lubricating a cone and a journal pin on an earth-boring bit, comprising: 
 circulating a lubricant from a bore in the journal pin, through a unidirectional valve, and into a gap between the cone and journal pin.    
   
   
       24 . The method of  claim 23 , further comprising the step of: 
 supplying said lubricant to the journal gap through a passageway that is separate from said bore.    
   
   
       25 . A method for dampening the movement between a cone cutter mounted on a journal pin extending from a bit body of an earth-boring bit, comprising: 
 allowing a lubricant to flow from a bore in the journal pin to a gap between the journal pin and the cone cutter when the cone cutter moves axially away from the bit body; and    restricting the flow of the lubricant from the gap through the bore in the journal pin when the cone cutter moves towards the bit body.    
   
   
       26 . A drill bit for drilling through earthen formations comprising: 
 a bit body having an extending journal pin;    a rolling cone cutter rotatably mounted on said journal pin;    a gap between said journal pin and said cone cutter;    a passage in said journal pin in fluid communication with said gap;    a bore in fluid communication with said passage and said gap; and    a means for permitting fluid flow through said bore in a first direction and restricting fluid flow through said bore in a second direction that is opposite said first direction.    
   
   
       27 . The drill bit of  claim 26  wherein said means for permitting fluid flow comprises a unidirectional valve in said bore.  
   
   
       28 . A cone movement dampener system for an earth-boring bit, comprising: 
 a journal pin having an outer surface including a first journal surface;    a cone disposed over said journal pin and having a second journal surface;    a journal gap formed between said first and second journal surfaces;    a grease passage in fluid communication with said journal gap;    a bore in said journal pin in fluid communication with said grease passage and extending through said outer surface of said journal pin; and    a means for permitting lubricant movement out of the bore and preventing lubricant movement into the bore.    
   
   
       29 . The system of  claim 28  wherein said means for permitting lubricant movement out of the bore and preventing lubricant movement into the bore comprises a spring biased ball valve.  
   
   
       30 . A drill bit, comprising: 
 a bit body having a journal pin and a lubricant source;    a rolling cone cutter coaxially aligned with and rotatably mounted on said journal pin;    a journal gap between said pin and said cone cutter;    a first lubricant passageway in fluid communication with said lubricant source and said journal gap;    a bore in said pin in fluid communication with said lubricant source and said gap for intermittently supplying lubricant to said gap; and    a unidirectional valve in said bore adapted to open in response to axial movement of said cone cutter away from said bit body and to close in response to axial movement of said cone cutter toward said bit body.