Passively adjustable elements for earth-boring tools and related tools and methods

Abstract

Passively adjustable elements for earth-boring tools may include a housing and an element located at least partially within the housing. A piston may be secured to the element, the piston configured to drive extension and retraction of the element relative to the housing. A first flow path may extend through the piston, through a first flow controller supported by the piston to permit fluid to flow at a first rate during retraction of the element. A second flow path may extend at least partially through the piston, through a second flow controller supported by the piston, to permit fluid to flow at a second, faster rate during extension of the element. A biasing element may bias the piston toward an extended position. An outer diameter of the piston may be less than or at least substantially equal to an outer diameter of the element.

1 . A passively adjustable element for an earth-boring tool, comprising:
 a housing;   an element located at least partially within the housing and extendable and retractable relative to the housing;   a piston located within the housing and secured to the element, the piston configured to drive extension and retraction of the element, wherein the piston and the housing cooperatively form a first chamber located at a first axial position along the piston and a second chamber located at a second, different axial position along the piston;   a first flow path extending from the first chamber, through the piston, through a first flow controller supported by the piston, to the second chamber, the first flow controller configured to permit fluid to flow from the first chamber to the second chamber at a first rate during retraction of the element and piston relative to the housing;   a second flow path extending from the second chamber, at least partially through the piston, through a second flow controller supported by the piston, to the first chamber, the second flow controller configured to permit fluid to flow from the second chamber to the first chamber at a second, faster rate during extension of the element and piston relative to the housing;   at least one sealing element located between the piston and the housing to axially separate the first chamber from the second chamber; and   a biasing element positioned and configured to bias the piston and element toward an extended position;   wherein an outer diameter of the piston as measured in a direction at least substantially perpendicular to a direction of extension and retraction of the element is less than or at least substantially equal to an outer diameter of the element.   
     
     
         2 . The passively adjustable element of  claim 1 , wherein the piston and the housing further cooperatively form a third chamber located at a third, different axial position along the piston and a fourth chamber located at a fourth, different axial position along the piston, the third chamber in fluid communication with the first chamber via the first flow path and located on an axial side of the second chamber opposite the first chamber, the fourth chamber in fluid communication with the second chamber via the second flow path and located on an axial side of the third chamber opposite the second chamber. 
     
     
         3 . The passively adjustable element of  claim 2 , further comprising a pressure-compensating element located within the housing, the pressure-compensating element configured to move relative to the housing to expand and contract a compensating volume located in the fourth chamber in response to extension and retraction of the piston and the element to compensate for temporary pressure differences between the first chamber and the second chamber. 
     
     
         4 . The passively adjustable element of  claim 1 , wherein an angle between a geometric center of the first flow path from the first chamber into the piston and a longitudinal axis of the piston is oblique. 
     
     
         5 . The passively adjustable element of  claim 4 , wherein the angle is about 45°. 
     
     
         6 . The passively adjustable element of  claim 1 , wherein a geometric center of the second flow path from the second chamber into the piston is perpendicular to a longitudinal axis of the piston. 
     
     
         7 . The passively adjustable element of  claim 1 , wherein the first chamber is located on an axial side of the second chamber opposite the element extendable and retractable relative to the housing. 
     
     
         8 . The passively adjustable element of  claim 7 , wherein the biasing element is located in the first chamber. 
     
     
         9 . The passively adjustable element of  claim 1 , further comprising a pressure-compensating element located within the housing, the pressure-compensating element configured to move relative to the housing to expand and contract a compensating volume in response to extension and retraction of the piston and the element to compensate for temporary pressure differences between the first chamber and the second chamber. 
     
     
         10 . The passively adjustable element of  claim 9 , wherein the compensating volume is in the second chamber. 
     
     
         11 . The passively adjustable element of  claim 9 , wherein the pressure-compensating element is located on an axial side of the second chamber opposite the first chamber and proximate to the element. 
     
     
         12 . The passively adjustable element of  claim 9 , wherein the pressure-compensating element is located on an axial side of the first chamber opposite the second chamber and opposite the element. 
     
     
         13 . The passively adjustable element of  claim 9 , wherein the pressure-compensating element comprises a pressure-compensating piston configured to move in a same direction as the piston and the element during extension and retraction. 
     
     
         14 . The passively adjustable element of  claim 9 , wherein the pressure-compensating element comprises a diaphragm configured to expand and retract laterally relative to the piston during extension and retraction of the element. 
     
     
         15 . The passively adjustable element of  claim 1 , wherein the element is selected from the group consisting of: a cutting element, a cutting insert, a depth-of-cut-control element, an ovoid, a gage pad, and a stabilizer pad. 
     
     
         16 . The passively adjustable element of  claim 1 , wherein the first flow controller comprises a restrictor and the second flow controller comprises a check valve. 
     
     
         17 . An earth-boring tool, comprising:
 a body; and   a passively adjustable element secured to the body, the passively adjustable element comprising:
 a housing secured within a pocket extending into the body; 
 an element located at least partially within the housing and extendable and retractable relative to the housing; 
 a piston located within the housing and secured to the element, the piston configured to drive extension and retraction of the element, wherein the piston and the housing cooperatively form a first chamber located at a first axial position along the piston and a second chamber located at a second, different axial position along the piston; 
 a first flow path extending from the first chamber, through the piston, through a first flow controller supported by the piston, to the second chamber, the first flow controller configured to permit fluid to flow from the first chamber to the second chamber at a first rate during retraction of the element and piston relative to the housing; 
 a second flow path extending from the second chamber, at least partially through the piston, through a second flow controller supported by the piston, to the first chamber, the second flow controller configured to permit fluid to flow from the second chamber to the first chamber at a second, faster rate during extension of the element and piston relative to the housing; 
 at least one sealing element located between the piston and the housing to axially separate the first chamber from the second chamber; and 
 a biasing element positioned and configured to bias the piston and element toward an extended position; and 
 wherein an outer diameter of the piston as measured in a direction at least substantially perpendicular to a direction of extension and retraction of the element is less than or at least substantially equal to an outer diameter of the element. 
   
     
     
         18 . The earth-boring tool of  claim 17 , wherein the housing of the passively adjustable element is secured within the pocket by a split ring forced at least partially into a complementary groove in the pocket by an expander. 
     
     
         19 . The earth-boring tool of  claim 17 , wherein the housing of the passively adjustable element is secured within the pocket by a collet secured within the pocket and threadedly engaged with the housing. 
     
     
         20 . A method of using an earth-boring tool having a passively adjustable element, comprising:
 engaging an earth formation utilizing an earth-boring tool;   retracting at a first rate an element to a greater extent within a housing secured to a body of the earth-boring tool in response to engaging the earth formation utilizing the earth-boring tool by compressing a biasing element biasing the piston and the element toward an extended position while flowing a hydraulic fluid along a first flow path extending from a first chamber located at a first axial position along a piston secured to, and movable with, the element, through the piston, through a first flow controller supported by the piston, to a second chamber located at a second, different axial position along the piston, an outer diameter of the piston as measured in a direction at least substantially perpendicular to a direction of extension and retraction of the element being less than or at least substantially equal to an outer diameter of the element;   extending at a second, faster rate the element relative to the housing in response to reducing engagement with the earth formation utilizing the earth-boring tool by permitting the biasing element to move the piston and the element toward the extended position while flowing the hydraulic fluid along a second flow path extending from the second chamber, at least partially through the piston, through a second flow controller supported by the piston, to the first chamber; and   fluidly isolating the first chamber from the second chamber utilizing at least one sealing element located between the piston and the housing.