Patent ID: 12203531

The application will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures.

DETAILED DESCRIPTION OF THE INVENTION

Before turning to the figures which illustrate the exemplary embodiments in detail, it should be understood that the application is not limited to the details or methodology set forth in the following description or illustrated in the figures. It should also be understood that the phraseology and terminology employed herein is for the purpose of description only and should not be regarded as limiting.

The present disclosure is directed to systems and methods that use advanced harmonic drives, advanced helical drives, and combinations thereof with 1) motors with axial pistons and reciprocating linear rings to convert reciprocative axial motion to continuous rotary motion, and 2) motors with rotary pistons and reciprocating linear rings to rectify reciprocative rotary motion to continual rotary motion to improve performance over prior configurations. The axial piston configuration presents a convenient solution for generating rotary shaft power. The rotary piston configuration increases torque output using rotational pistons whereby output torque is proportional to the length of the rotary pistons; hence the pistons can be prescribed of the length necessary to generate a desired torque. Furthermore, an increased number of pistons may be used for greater torque. The form factor presented by rotational pistons allows flow through the piston section so fluid particulates will not settle out within the piston assembly. The disclosed motors have improved torque, do not introduce lateral vibration and can operate at high temperatures. The rotary piston configuration has improved particle settling characteristics.

FIG.1illustrates an internal power section of a fluid-powered axial or linear motor module (internal power section)10according to an embodiment of the disclosure. The linear motor module or internal power section10may provide power to or be coupled to a tool or other component or other power section that uses or receives the generated rotary motion of the internal power section10. As can be seen inFIG.1, the internal power section10includes a primary rotor assembly20, a linear piston assembly40and a harmonic drive reciprocating ring (harmonic drive ring)50. Additional components not seen are discussed in further detail below. The internal power section10has aft end or fluid inlet11and a fore end or fluid outlet12. The internal power section10receives fluid at the aft end that drives the primary rotor assembly20that drives a harmonic reciprocating ring50to drive a harmonic drive rotor60(seeFIG.2) attached to the primary rotor assembly20to impart a continual rotation thereto, the fluid discharged thereafter from the fluid outlet12.

The linear piston assembly40includes an aft piston assembly41and a fore piston assembly42. The aft and fore piston assemblies41,42provide surface area that receives fluid pressure when the fluid chambers are alternatingly pressurized to drive the harmonic drive ring50in reciprocating linear axial directions. The aft and fore piston assemblies41,42are attached to the harmonic drive ring50(seeFIGS.1,3and3A).

FIG.2illustrates a primary rotor assembly20and harmonic drive rotor60according to an embodiment of the disclosure. The primary rotor assembly20ports fluid to the fore and aft piston chambers28a,28b, (seeFIG.7) as it rotates. The piston chambers28a,28bare defined by the primary rotor shaft21, thrust bearing flanges22piston assemblies,41,42and liner72. The primary rotor assembly20produces torque in response to the harmonic drive ring50moving across the harmonic drive rotor60. The primary rotor assembly20includes a primary rotor shaft21, thrust bearing flanges22, and end retainers23. The primary rotor assembly20also includes an aft primary shaft fluid outlet (pressure) valve24aand an aft primary shaft fluid inlet (exhaust) valve25aand a fore primary shaft fluid outlet (pressure) valve24band a fore primary shaft fluid inlet (exhaust) valve25bthat provide fluid to the aft and fore fluid chambers, respectively.

The thrust bearing flanges22react the force from the action of the harmonic drive reciprocating ring50(FIG.1). There are two thrust bearing flanges22, an aft thrust bearing flange22aproximate the fluid inlet21aand a forward thrust bearing flange22bproximate the fluid outlet21b.

The end retainers23retain the various components comprising the subassembly on the primary rotor shaft. There are two end retainers23, a first end retainer or locknut23adisposed on the shaft21proximate the fluid inlet21aand a second end retainer or shaft collar23bdisposed proximate the fluid outlet21b.

The primary shaft fluid outlet valves24a,24ballow a portion of the fluid entering the shaft fluid inlet21aand flowing through a shaft internal pressurized flow channel (not shown), which flows between the primary shaft fluid inlet21aand the primary shaft fluid outlet21b, to exit the shaft internal pressurized flow channel and drive the harmonic drive reciprocating ring50. The primary fluid inlet valve25allows the fluid that has been exhausted by the harmonic drive reciprocating ring50to return to a shaft internal flow channel separate from the pressurized fluid flowing through the shaft internal pressurized flow channel. Pressurized fluid exits at valve24aand pressurizes chamber A causing exhaust fluid in Chamber B to enter valve25bto return to the shaft internal flow channel. When the harmonic drive reciprocating ring reaches the end of its stroke, pressurized fluid exits at valve24band pressurizes chamber B causing exhaust fluid in Chamber A to enter valve25ato return to the shaft internal flow channel. Both the pressurized fluid flowing through the shaft internal pressurized flow channel and the fluid that has performed work by driving the harmonic drive reciprocating ring50are discharged as separate streams at the shaft fluid outlet21b.

The harmonic drive rotor60is a cylindrical sleeve that has ball track grooves60athat allow seating of balls in harmonic drive reciprocating ring50. The balls may be referred to as ball transfers as the balls “transfer” the thrust load in the ring produced by differential pressure across the harmonic drive reciprocating ring50into an applied force on the harmonic drive rotor60to produce torque in the rotor. In this exemplary embodiment, the harmonic drive rotor60includes six ball track grooves60a. In other embodiments, the harmonic drive rotor60may include one or more ball track groves60a. In an embodiment, only one ball track groove is required if the piston is not bi-directional. In another embodiment, the harmonic drive rotor60may include two or more ball track grooves60a. The number of grooves is determined by the torque/performance requirements. In yet other embodiments, the harmonic drive rotor60may include a number of ball track grooves60aas necessary to transmit the torque requirements of its intended use. The ball track grooves60aform a recirculating path around the harmonic drive to convert harmonic, cycloidal or polynomial motion in the harmonic drive reciprocating ring50to rotary motion in the primary rotor assembly. The harmonic drive rotor60converts reciprocating motion in the harmonic drive reciprocating ring50to continuous rotary motion in primary rotor assembly20. The harmonic drive rotor60is joined to, affixed or otherwise attached to the primary rotor assembly20so that imparting rotation to the harmonic drive rotor60imparts rotation to the primary rotor assembly20.

FIGS.3and3Aillustrate a linear piston assembly40and a harmonic drive reciprocating ring (harmonic drive ring)50according to an embodiment of the disclosure. The linear piston assembly40includes piston body43and outer diameter piston seal44and inner diameter piston seal46. The linear piston assembly40receives fluid from valves24and exhausts fluid from valves25as described above.

As can further be seen inFIGS.3and3A, the harmonic drive ring50includes a housing52, a plurality of inner ball transfer outer race housings53and an outer ball transfer race housing54that include a plurality of ball transfer outer races53aand54aand a plurality of track, roller balls (balls)55disposed within the plurality of ball transfer outer races53aand54a. The plurality of inner ball transfer outer race housings53and outer ball transfer race housing54may be referred to as the harmonic drive outer race. The plurality of ball transfer outer races53aand54acontain one or more balls55so that a portion of the balls extend towards the axial centerline of the housing52beyond the inner wall52aof the housing52and the plurality of ball transfer outer race housings53and54. Shims57are installed at assembly between the outer race housings to ensure dimensional fit between the outer race housings and harmonic drive rotor ball track grooves60a.

The harmonic drive ring50is disposed around and concentric to the harmonic drive rotor60(FIG.2). The one or more balls55engage and track in corresponding harmonic track grooves60aof the harmonic track rotor60(FIG.2). In such a manner, the balls55and harmonic track grooves60aare in load bearing contact and the balls55rotate in the ball transfer outer race54as the harmonic drive rotor60rotates.

FIG.4is a lateral cross-sectional view through a [1:2] harmonic drive with the harmonic drive ring50illustrating the planetary drive train nature of the assembly comprising sun, planet, ring and carrier components corresponding to the harmonic drive rotor groove60a, ball55, outer race53a/54aand ball orbit diameter56, respectively. As the rotor (sun) rotates, the ball (planet) will orbit the rotor (sun). In accordance with design convention, the diameters of these components must be dimensioned proportionally to ensure rolling motion at their contact points within the harmonic drive.

FIG.5is a table of values showing typical rotor-stator combinations [A:B] for harmonic drive assemblies; “alpha” values, governing the ratio of outer race diameter on the race retainer53a/54ato the inner race diameter on the harmonic drive rotor60a, is computed as the ratio B divided by A (i.e., B/A), and establishes the criterion for pure rolling motion within the harmonic drive assembly.

FIGS.6and6Aillustrates a liner assembly (liner)72according to an embodiment of the disclosure. In this exemplary disclosure, the liner72is formed from multiple segments for ease of assembly of the motor module80(seeFIG.7). In other embodiments, the liner72may be formed of one or more components. The liner72acts as a stator and forms the interface between the motor case (shell) and the rotor assembly shown inFIG.7. As can be seen inFIGS.6and6A, the liner72includes a housing73having external splines73aand internal splines73b. The external splines73aengage with the motor case or shell101(seeFIG.9) to prevent rotation of the liner72as the liner72reacts the torque from the reciprocating ring (50) on the interior surface using internal splines73bto prevent the ring50from rotating. Thrust bearings78aand78bare shown installed within the liner inFIG.6Aand act to react rotor thrust loads during operation.

FIG.7is a partial cross section view of a motor module80according to an embodiment of the disclosure with the liner72cutaway. The rotor assembly70shown inFIG.7is shown installed in the cut-away of the liner72. The aforementioned thrust bearings78aand78band rotary bearings79aand79b(shown inFIG.6A) integrate the rotor assembly with the liner.

FIG.8shows the complete motor module80with sectional references forFIGS.8A-8Findicated. As can be seen inFIGS.8A-8F, the liner72afurther includes fluid injection ports74(fluid injection port74a—Chamber A) and fluid relief ports75(fluid ejection port75a—Chamber A) where Chamber A is the volume in liner72bbetween the piston41and the liner72a. The liner72efurther includes fluid injection ports74(fluid injection port74b—Chamber B) and fluid relief ports75(fluid ejection port75B—Chamber B) where Chamber B is the volume in liner72dbetween the piston42and the liner72e. These are described below using the various sections through the motor module80inFIG.8.

FIGS.8A-8Fshows how alternatively pressurizing and exhausting Chambers A and B impart reciprocative axial motion to motor pistons to generate rotation and torque in the output rotor. As discussed below, Chamber A is pressurized while Chamber B is concurrently exhausted to energize the rotor assembly to impart forward motion to the axial pistons to generate clockwise motion in the output rotor, followed by alternatively porting Chamber B to pressurize while Chamber A is concurrently exhausted to energize the rotor assembly to impart backward motion to the axial pistons to generate clockwise motion in the output rotor.

The fluid injection ports74receive fluid from the primary shaft fluid outlet (pressure) valve24(seeFIGS.8Asection1-1and8D section4-4) and port it to the axial piston Chambers A and B (seeFIG.8Csection3-3and seeFIG.8Fsection6-6-). Fluid injection port74aconnects rotor primary shaft fluid outlet valve24ato rotary piston Chamber A via flow through the liner72a; fluid injection port74bconnects rotor primary shaft fluid outlet valve24bto rotary piston Chamber B via flow through the liner72e. These fluid injection ports74a&74bconnect alternatively during rotor rotation to pressurize the chambers for axial piston reciprocation. (Note the referenced figures show the beginning of Chamber A pressurization and completion of Chamber B pressurization corresponding to clockwise rotation of the rotor assembly when viewed from the aft end of the assembly.)

The fluid relief port75receives fluid from the rotary piston chambers (seeFIG.8Bsection2-2and seeFIG.8Esection5-5) for ejection to the rotor primary shaft fluid inlet (exhaust) valve25. Fluid injection port75a(seeFIG.8Bsection2-2) connects rotor primary shaft fluid outlet valve25to rotary piston Chamber A; fluid injection port75b(seeFIG.8Esection5-5) connects rotor primary shaft fluid outlet valve25to rotary piston Chamber B. These fluid ejection ports75a&75bconnect alternatively during rotor rotation to exhaust the chambers for rotary piston reciprocation.

The fluid relief port75a&75bdirect fluid to the exhaust manifold described inFIG.10below.

FIG.9illustrates a partial cut away view of a fluid-powered linear motor (motor)100according to an embodiment of the disclosure. As can be seen inFIG.9, the motor100includes a first motor module100aand a second motor module100b. In other embodiments, a motor100may include two or more modules depending on the torque requirements of the application. The motor100requires the second motor module100bto be assembled rotationally clocked from the first motor module100ato provide a continuous output torque as the individual modules can then transition the respective dwell point or motion reversals of their piston reciprocation while the other module is providing rotor power. Additional modules can be added and similarly offset to allow continuous rotor torque during constituent module dwell points and provide increased torque delivery for the overall assembly.

Also shown inFIG.9is a case or shell101that accommodates installation of the constituent motor modules including a splined bore to receive liner assembly72and mate with housing73and external splines73a. The shell101is secured (preloaded) with a connection (threaded or welded) to hold the motor in place.

It should be appreciated that the primary rotor shaft of the motor may be connected or coupled to a rotary tool or device, such as, but not limited to a rotary cutter or bit, via a rotating collar at the forward end of the shell. Likewise, the aft end of the shell may be connected to a drillstring such that the motor introduces rotary motion relative to the drillstring connection. In addition, the motor receives a fluid from a drillstring connection or other fluid supply source as may be appreciated by one of ordinary skill in the art.

FIG.10illustrates fluid flow paths through the motor100(FIG.9). As discussed above, the fluid entering each module is separated into a working fluid flow that energizes the harmonic drive reciprocating ring assembly of that module and a pressure fluid flow that passes through the primary rotor shaft of that module and an exhaust flow that may have been collected from previous modules. The working fluid, after performing work, is exhausted from that module as an exhaust flow. The exhaust flow is then provided to downstream module(s) to continue to pass through the motor. The pressure fluid flow, after passing through a module, is provided to a downstream module to power the harmonic drive reciprocating ring assembly of that downstream module. Similarly, exhaust fluid flows from upstream modules must be isolated from pressure fluid flows that have yet to perform work until all exhaust fluid can be collected at the motor exit.

As can be seen inFIG.10, an exhaust piping manifold90is assembled with subassembly91disposed within the first module100a(seeFIG.10) and subassembly92disposed within the second module100b(seeFIG.10) with the assemblies interconnected by exhaust tube96. For the two-module motor under consideration, centralizer93is disposed within the first module and as such does not collect any exhaust flows from previous modules; it does allow pressurized fluid to the downstream module and accordingly has flutes cut in its periphery to allow pressurized fluid to flow by. Pressurized fluid is delivered to Chamber A of the first module, performs work, is collected as exhaust fluid at centralizer93, and conveyed to exhaust tube94for pass through module2. Pressurized fluid is delivered to Chamber B of the first module, performs work, is collected as exhaust fluid at centralizer95, combined with flow from Chamber A and conveyed to exhaust tube96for pass through module2. Centralizer95also includes flutes to allow pressurized fluid to flow by to module2. Pressurized fluid is conveyed across these flutes within the primary rotor of module1and delivered to module2. Pressurized fluid is delivered to the second module proximate centralizer96, performs work, collected as exhaust fluid at centralizer97for Module2Chamber A and at centralizer99for Module2Chamber B, and combined with exhaust flow in exhaust tube98and allowed to exit the motor assembly. Comparable fluid management flow manifolds can be conceived for motors consisting of more than two modules with exhaust manifolds configured for each module according to the sequential connection of the assembly.

FIGS.11and12show the axial reciprocation of the harmonic drive reciprocating ring assembly and the corresponding rotor rotation.FIG.11is a partial cross section view of a motor module10at the commencement of a stroke according to an embodiment of the disclosure, with liner assembly cutaway illustrating right-ward reciprocating harmonic drive reciprocating ring assembly motion at commencement of stroke. As can be seen inFIG.11, fluid is driving the harmonic drive reciprocating ring assembly50to the right in a direction that imparts forward linear motion A to the harmonic drive ring50(driving them in the direction indicated by A) such that the harmonic drive ring50imparts clockwise rotation B to the primary rotor assembly26.

FIG.12is a partial cross section view of a motor module according to an embodiment of the disclosure with liner assembly cutaway illustrating left-ward reciprocating harmonic drive reciprocating ring assembly motion at completion of a stroke. As can be seen inFIG.12, fluid is driving the harmonic drive reciprocating ring assembly50to the left in direction that imparts backward linear motion A′ to the harmonic drive ring50such that the harmonic drive ring50imparts clockwise rotation B to the primary rotor assembly26.

Operation

The operation of an axial piston motor is as follows. As the rotor rotates, the valves within the first valve block assembly open to allow fluid pressure and flow into chamber A of the axial piston assembly at the upstream end. The fluid pressure drives the axial pistons forward exhausting the fluid from chamber B at the downstream end. The exhaust fluid is directed to the exhaust ports in the lower valve block assembly. The exhaust valves allow flow from chamber B into the exhaust manifold on rotor centerline.

As the axial pistons move forward, the harmonic drive rings apply a force to the ball(s) in the reversing track of the harmonic drive and introduces clockwise rotation and torque to the output rotor.

As the axial pistons reach the end of stroke, the pressure and exhaust valves reverse port connections and the pressurized fluid is directed to chamber B and the fluid is exhausted from chamber A. This produces reverse motion in the axial pistons. Since the ball(s) in the harmonic drive had reached the dwell point at the end of the chamber A pressurization stroke, the ball(s) in the harmonic drive is now on the reversing track of the harmonic drive. As the harmonic drive rings retract during pressurization of chamber B, clockwise motion and torque are delivered to the output rotor. When the axial piston reaches the end of stroke, the harmonic drive(s) reaches another dwell point and the cycle is complete. The cycle repeats itself with the subsequent pressurization of chamber A and exhaust of chamber B as the rotor valves return to their initial conditions following one full or fractional rotation of the rotor.

Configurations

This paragraph describes the available configurations using the axial piston motor and the harmonic drive.

FIG.13Ais an illustration of a harmonic drive rotor60according to the present embodiment of the disclosure. As can be seen inFIG.13A, the rotor track has one harmonic per revolution.

FIG.13Bis an illustration of a harmonic drive rotor60according to the present embodiment of the disclosure. As can be seen inFIG.13B, the rotor track has two harmonics per revolution.

FIG.13Cis an illustration of a harmonic drive rotor60according to the present embodiment of the disclosure. As can be seen inFIG.13C, the rotor track has three harmonics per revolution.

FIG.14Ais an illustration of a ball transfer outer race53/54according to an embodiment of the disclosure. As can be seen inFIG.14A, the outer race has two harmonics per revolution, resulting in pi radians of ball advance along the ball orbit per harmonic drive reciprocating ring reciprocation cycle. The rotor will concurrently advance by a factor of (alpha+1) greater than the ball orbital advance in accordance with planetary drive train principles for rolling motion at the contact interfaces. Hence, the rotary displacement of the rotor can be tailored by selecting the dimensional properties of ball transfer outer race housing and matching harmonic drive rotor in accordance with the definition of alpha defined previously.

FIG.14Bis an illustration of a ball transfer outer race53/54according to another embodiment of the disclosure. As can be seen inFIG.14B, the outer race has three harmonics per revolution, resulting in 2pi/3 radians of ball advance along the ball orbit per harmonic drive reciprocating ring reciprocation cycle. The rotor will concurrently advance by a factor of (alpha+1) greater than the ball orbital advance. Hence, the rotary displacement of the rotor can be tailored by selecting the dimensional properties of ball transfer outer race housing and matching harmonic drive rotor in accordance with the definition of alpha defined previously.

FIG.14Cis an illustration of a ball transfer outer race53/54according to the present embodiment of the disclosure. As can be seen inFIG.14C, the outer race has four harmonics per revolution, resulting in pi/2 radians of ball advance along the ball orbit per harmonic drive reciprocating ring reciprocation cycle. The rotor will advance concurrently by a factor of (alpha+1) greater than the ball orbital advance. Hence, the rotary displacement of the rotor can be tailored by selecting the dimensional properties of ball transfer outer race housing and matching harmonic drive rotor in accordance with the definition of alpha defined previously.

Comparing ring reciprocation (axial amplitude) of the harmonic drives inFIG.13A-13Cwith reciprocating harmonic drive reciprocating piston/ring assemblies inFIGS.14A-13Cshows available design variation. For example, in accordance with the definition of alpha inFIG.5: 1) the outer race ofFIG.14Acan be matched with the harmonic drive rotor ofFIG.13A; 2) the outer race ofFIG.14Bcan be matched with the harmonic drive rotor ofFIG.13AorFIG.13B; 3) the outer race ofFIG.14Ccan be matched with the harmonic drive rotor ofFIG.13AorFIG.13BorFIG.13C. Multiple configurations can be conceived by selecting the properties of the overall assembly components to achieve the desired rotor output speed and torque based upon input flow and pressure conditions.

FIG.15illustrates an internal power section of a fluid-powered linear motor module (internal power section)110according to an embodiment of the disclosure. The linear motor module or internal power section110may provide power to or be coupled to a tool or other component or other power section that uses or receives the generated rotary motion of the internal power section110. As can be seen inFIG.15, the internal power section110includes a primary rotor assembly120, a secondary reciprocating rotor assembly130, a helical drive reciprocating ring (helical drive ring)140and a harmonic drive reciprocating ring (harmonic drive ring)150. Additional components not seen are discussed in further detail below. The internal power section110has aft end or fluid inlet111and a fore end or fluid outlet112. The internal power section110receives fluid at the aft end that drives the secondary reciprocating rotor assembly that drives the helical and harmonic reciprocating rings to drive a harmonic drive rotor (described below) attached to the primary rotor assembly to impart a continual rotation thereto, the fluid discharged thereafter from the fluid outlet.

FIG.16illustrates a primary rotor assembly120and harmonic drive rotor160according to an embodiment of the disclosure. The primary rotor assembly120ports the fluid to the piston chambers as it rotates. The primary rotor assembly120produces torque in response to the harmonic drive ring150moving across the harmonic drive rotor160. The primary rotor assembly120includes a primary rotor shaft121, thrust bearing flanges122, and end retainers123. The primary rotor assembly120also includes a primary shaft fluid outlet (pressure) valve124and a primary shaft fluid inlet (exhaust) valve125.

The thrust bearing flanges122react the force from the action of the harmonic drive reciprocating ring150. There are three thrust bearing flanges122, an aft thrust bearing flange122aproximate the fluid inlet121a, a forward thrust bearing flange122bproximate the fluid outlet121b, and a primary/secondary rotor bearing flange122cproximate the middle of the shaft121.

The end retainers123retain the various components comprising the subassembly on the primary rotor shaft. There are two end retainers123, a first end retainer or locknut123adisposed on the shaft121proximate the fluid inlet121aand a second end retainer or shaft collar123bdisposed proximate the fluid outlet121b.

The primary shaft fluid outlet valve124allows a portion of the fluid entering the shaft fluid inlet121aand flowing through a shaft internal pressurized flow channel (not shown), which flows between the primary shaft fluid inlet121aand the primary shaft fluid outlet121b, to exit the shaft internal pressurized flow channel and drive the secondary reciprocating rotor assembly130. The primary fluid inlet valve125allows the fluid that has driven the secondary reciprocating130to return to a shaft internal flow channel separate from the pressurized fluid flowing through the shaft internal pressurized flow channel. Both the pressurized fluid flowing through the shaft internal pressurized flow channel and the fluid that has performed work by driving the secondary reciprocating rotor assembly130are discharged as separate streams at the shaft fluid outlet121b.

The harmonic drive rotor160is a cylindrical sleeve that has ball track grooves160athat allow seating of ball transfers in harmonic drive reciprocating ring150. The ball track grooves160aform a recirculating path around the harmonic drive to convert harmonic, cycloidal or polynomial motion in the harmonic drive reciprocating ring150to rotary motion in the primary rotor assembly. The harmonic drive rotor160converts reciprocating motion in the harmonic drive reciprocating ring150to continuous rotary motion in primary rotor assembly120. The harmonic drive rotor160is joined to, affixed or otherwise attached to the primary rotor assembly120so that imparting rotation to the harmonic drive rotor160imparts rotation to the primary rotor assembly120.

FIG.17illustrates a secondary reciprocating rotor assembly130according to an embodiment of the disclosure. The secondary reciprocating rotor assembly130is concentric to the primary rotor assembly120and can reciprocatedly rotate thereabout. The secondary reciprocating rotor assembly130includes a secondary reciprocating rotor (secondary rotor)131, a reciprocating rotary piston assembly132, and a helical drive screw assembly133. The reciprocating rotary piston assembly132includes a housing132a, reciprocating rotary motor blades or pistons132band splines132cinternal to the housing132a. The reciprocating rotary piston assembly132shows an end view of the secondary rotor132so as to show secondary rotor splines131athat engage with the splines132cof the reciprocation rotary piston assembly132.

The secondary rotor131is disposed concentrically around the primary rotor shaft121(seeFIG.14). As discussed above, the secondary rotor131includes secondary rotor splines131athat engage with splines132cinternal to the reciprocating rotary piston assembly132and splines internal to the helical drive screw assembly133(not shown), so that reciprocating rotary motion imparted to the reciprocating rotary piston assembly132rotates the helical drive screw assembly133in a reciprocating manner as well.

The helical drive screw assembly133includes helical drive screw spacers (spacers)134on both sides of a helical drive screw135. The spacers134include a fore drive screw spacer134aand an aft drive screw spacer134b. The spacers134have internal splines that couple the spacers134to the secondary rotor131. The aft drive screw spacers134aabuts against a bearing flange136coupled to the secondary rotor131via mating splines. The bearing flange136reacts thrust load from the helical drive reciprocating ring140to a thrust bearing178e(seeFIG.22A). The fore drive screw spacer134bis coupled to a flange137. The bearing flange137reacts thrust load from the helical drive reciprocating ring140to the primary/secondary thrust bearing122(seeFIG.18).

The helical drive screw135is a cylindrical sleeve that has ball track grooves135athat allow seating of ball transfers145(seeFIGS.19and19A) in helical drive reciprocating ring140. The ball track grooves135aform a non-recirculating path around the helical drive to convert reciprocating rotary motion in the secondary rotor assembly to reciprocating motion in the helical drive reciprocating ring140.

FIG.18illustrates a composite rotary assembly170according to an embodiment of the disclosure. As can be seen inFIG.18, the composite rotary assembly170is formed by concentrically assembling the secondary reciprocating rotor assembly130and the primary rotor assembly120. The secondary reciprocating rotor assembly130is positioned longitudinally on the primary rotor assembly120by 1) abutting flange137on primary/secondary thrust bearing flange (flange)122cwith a thrust bearing178ain the interstitial space between the flanges122cand137at the interface between the secondary reciprocating rotor assembly130and the primary rotor assembly120and 2) abutting the reciprocating rotary piston assembly130against flange122awith a thrust bearing178bin the interstitial space between reciprocating rotary piston assembly130. The helical drive ring140(seeFIGS.21and21B), the helical drive screw135, the harmonic drive ring150(seeFIGS.21and21A), and the harmonic drive rotor160may be referred to as mechanical rectifier.

FIGS.19and19Aillustrate a helical drive reciprocating ring (helical drive ring)140and a connecting flange141according to an embodiment of the disclosure. As can be seen inFIGS.19and19A, the helical drive ring140includes a housing142a plurality of inner ball transfer outer race housings143and an outer ball transfer race housing144that include a plurality of ball transfer outer races143aand144aand a plurality of track, roller balls (balls)145disposed within the plurality of ball transfer outer races143aand144a. The plurality of inner ball transfer outer race housings143and outer ball transfer race housings144may be referred to as the helical drive outer race. The plurality of ball transfer outer races143aand144acontain one or more balls145so that a portion of the balls extend towards the axial centerline of the housing148beyond the inner wall142aof the housing142and the plurality of ball transfer outer race housings143and144. Shims147are installed at assembly between the outer race housings to ensure dimensional fit between the outer race housings and helical drive rotor ball track grooves135a(seeFIG.19A). The connecting flange141includes an insert portion141athat is used to rigidly connect the helical drive ring140to the harmonic drive ring150. The connecting flange141also includes an opposing insert portion (not shown) disposed within and rigidly connected to the helical drive ring140.

The helical drive ring140is disposed around and concentric to the helical drive screw assembly133(FIGS.15,17,18). The plurality of balls145engage and track in corresponding track grooves135aof the helical drive screw135(FIGS.15,17,18). In such a manner, the balls145and track grooves135aare in load bearing contact and the balls145rotationally reciprocate in the ball transfer outer race retainer144as the helical drive screw135reciprocates.

FIG.20is a lateral cross-sectional view through the helical drive ring illustrating the planetary drive train nature of the assembly comprising sun, planet, ring and carrier components corresponding to the helical drive rotor135a, ball155, outer race154a, and ball orbit diameter156respectively of the earlier embodiment, which is the same functional relationship as in this embodiment. As the rotor (sun) rotates, the ball (planet) will reciprocatedly orbit the rotor (sun). In accordance with design convention, the diameters of these components must be dimensioned proportionally to ensure rolling motion at their contact points within the helical drive. “Alpha” values, governing the ratio of outer race diameter on the race retainer144ato the inner race diameter on the helical drive rotor135amust be observed for pure rolling motion at the contact points within the helical drive assembly.

FIGS.21and21Aillustrate a [3:6] harmonic drive reciprocating ring (harmonic drive ring)150according to an embodiment of the disclosure. As can be seen inFIGS.21and21A, the harmonic drive ring150includes a housing152, a plurality of inner ball transfer outer race housings153and an outer ball transfer race housing154that include a plurality of ball transfer outer races153aand154aand a plurality of track, roller balls (balls)155disposed within the plurality of ball transfer outer races153aand154a. The plurality of inner ball transfer outer race housings153and outer ball transfer race housing154may be referred to as the harmonic drive outer race. The plurality of ball transfer outer races153aand154acontain one or more balls155so that a portion of the balls extend towards the axial centerline of the housing152beyond the inner wall152aof the housing152and the plurality of ball transfer outer race housings153and154. Shims157are installed at assembly between the outer race housings to ensure dimensional fit between the outer race housings and harmonic drive rotor ball track grooves60a.

The harmonic drive ring150is disposed around and concentric to the harmonic drive rotor160(FIGS.16,18). The plurality of balls155engage and track in corresponding harmonic track grooves160aof the harmonic track rotor160(FIGS.16,18). In such a manner, the balls155and harmonic track grooves160aare in load bearing contact and the balls155rotate in the ball transfer outer race housings154as the harmonic drive rotor160rotates.

FIGS.22and22Aillustrates a liner assembly (liner)172according to an embodiment of the disclosure. In this exemplary disclosure the liner172is formed from multiple segments for ease of assembly of the motor module180(seeFIG.23). In other embodiments, the liner172may be formed of one or more components. The liner172acts as a stator and forms the interface between the motor case (shell) and the rotor assembly shown inFIG.18. As can be seen inFIGS.22and22A, the liner172includes a housing173having external splines173aand internal splines173b. The external splines173aengage with the motor case or shell201(seeFIG.25) to prevent rotation of the liner172as the liner172reacts the torque from the reciprocating rings (140,150) on the interior surface using internal splines173bto prevent the rings140,150from rotating. Thrust bearings178c,178d,178e,178fare shown installed within the liner inFIG.22Aand act to react rotor thrust loads during operation. Also shown inFIG.22Aare rotary bearings179a&179bthat centralize the rotor assembly (FIG.18) within the liner172and rotary bearings179c&179dthat centralize the rotary piston132(FIG.17) within the liner172.

As can be seen inFIG.22A, the liner172includes stator ribs171disposed there within. These stator ribs171interface with the rotary piston132to form cavities or chambers (e.g., chambers “A” & “B”) that facilitate chamber pressurization in response to the following fluid pressurization sequence. As discussed in further detail below, adjacent rotary pistons132have a stator rib171disposed therebetween so as to divide the space therebetween into chambers “A” and “B.” The internal components173cinclude ports to receive fluid from the pressure valve124and convey the fluid to the chambers as described in further detail below. It should be noted that internal components173are shown solid at the cut away but contain ports internal thereto.

FIG.23is a partial cross section view of a motor module180according to an embodiment of the disclosure with the liner172cutaway. The rotor assembly170shown inFIG.18is shown installed in the cut-away of the liner172a. The aforementioned thrust bearings178c,178d,178e,178fand rotary bearings179a,179b,179c&179d(shown inFIG.22A) integrate the rotor assembly with the liner.

FIG.24shows the complete motor module180with sectional references forFIGS.24A-24Hindicated. As can be seen inFIGS.24A-24H, the liner172afurther includes fluid injection ports174(fluid injection port174a—Chamber A, fluid injection port174b—Chamber B) into rotary piston stator172b, a fluid relief port175(fluid relief port175a—Chamber A, fluid relief port175b—Chamber B) in liner172c, a fluid channel176(fluid relief port176a—Chamber A—external to liner172d, fluid relief port176b—Chamber B—internal to liner172d) and a fore fluid inlet port177(fluid relief port177a—Chamber A, fluid relief port177b—Chamber B in liner172e). These are described below using the various sections through the motor module180inFIG.24.

FIGS.24A-24Hshows how alternatively pressurizing and exhausting Chambers A and B impart reciprocative rotary motion to motor pistons to generate rotation and torque in the output rotor. As discussed below, Chamber A is pressurized while Chamber B is concurrently exhausted to energize the rotor assembly to impart clockwise motion to the rotary pistons to generate clockwise motion in the output rotor, followed by alternatively porting Chamber B to pressurize while Chamber A is concurrently exhausted to energize the rotor assembly to impart counter-clockwise motion to the rotary pistons to generate clockwise motion in the output rotor.

The fluid injection ports174receive fluid from the primary shaft fluid outlet (pressure) valve124(seeFIGS.24Asection1-1and24B section2-2) and port it to the rotary piston Chambers A and B (seeFIG.24Csection3-3). Fluid injection port174aconnects rotor primary shaft fluid outlet valve124ato rotary piston Chamber A via flow through the liner172a; fluid injection port174bconnects rotor primary shaft fluid outlet valve124bto rotary piston Chamber B via flow through the liner172a. These fluid injection ports174a&174bconnect alternatively during rotor rotation to pressurize the chambers for rotary piston reciprocation. (Note the referenced figures show the beginning of Chamber A pressurization and completion of Chamber B pressurization corresponding to clockwise rotation of the rotor assembly.)

The fluid relief port175receives fluid from the rotary piston chambers (seeFIG.29Csection3-3) for ejection to the rotor primary shaft fluid inlet (exhaust) valve125via fluid channel176and fore fluid port177. Fluid injection port175a(seeFIG.24Dsection4-4) connects rotor primary shaft fluid outlet valve125to rotary piston Chamber A via fluid channel176a(described below) and fore fluid port177a(described below); fluid injection port175bconnects rotor primary shaft fluid outlet valve125to rotary piston Chamber B via fluid channel176b(described below) and fore fluid port177b(described below). These fluid ejection ports175a&175bconnect alternatively during rotor rotation to exhaust the chambers for rotary piston reciprocation.

The fluid channel176areceives fluid from the fluid relief port175for ejection to the rotor primary shaft fluid inlet (exhaust) valve125via fore fluid port177. Fluid injection port176a, one or more cavities in the exterior of liner172d(seeFIGS.24Esection5-5and24D section6-6) connects rotor primary shaft fluid outlet valve125to rotary piston Chamber A via fore fluid port177a; fluid injection port176b, flow across the helical drive reciprocating140(seeFIG.24Esection5-5) in the interior of liner172dand harmonic drive reciprocating ring150(seeFIG.24Fsection6-6) in the interior of liner172dconnects rotor primary shaft fluid outlet valve125to rotary piston chamber “B” via fore fluid port177b. These fluid channels176a&176bconnect alternatively during rotor rotation to exhaust the chambers for rotary piston reciprocation.

The fore fluid inlet port177receives fluid from the fluid channel176for ejection to the rotor primary shaft fluid inlet (exhaust) valve125. Fore fluid inlet port177a(seeFIG.24Gsection7-7) connects rotor primary shaft fluid outlet valve125to rotary piston chamber “A” via fluid channel176aand flow through the liner172e; fore fluid inlet port177b(seeFIG.24Hsection8-8) connects rotor primary shaft fluid outlet valve125to rotary piston Chamber B via fluid channel176b, fluid injection port176band flow through the liner172e. These fore fluid inlet ports177a&177bconnect alternatively during rotor rotation to exhaust the chambers for rotary piston reciprocation.

FIG.25illustrates a partial cut away view of a fluid-powered linear motor (motor)200according to an embodiment of the disclosure. As can be seen inFIG.25, the motor200includes a first motor module200aand a second motor module200b. In other embodiments, a motor200may include two or more modules depending on the torque requirements of the application. The motor200requires the second motor module200bto be assembled rotationally clocked from the first motor module200ato provide a continuous output torque as the individual modules can then transition the respective dwell point or motion reversals of their piston reciprocation while the other module is providing rotor power. Additional modules can be added and similarly offset to allow continuous rotor torque during constituent module dwell points and provide increased torque delivery for the overall assembly.

Also shown inFIG.25is a case or shell201that accommodates installation of the constituent motor modules including a splined bore to receive liner assembly172and mate with housing173and external splines173a. The shell201is secured (preloaded) with a connection (threaded or welded) to hold the motor in place.

It should be appreciated that the primary rotor shaft of the motor may be connected or coupled to a rotary tool or device, such as, but not limited to a rotary cutter or bit, via a rotating collar at the forward end of the shell. Likewise, the aft end of the shell may be connected to a drillstring such that the motor introduces rotary motion relative to the drillstring connection. In addition, the motor receives a fluid from a drillstring connection or other fluid supply source as may be appreciated by one of ordinary skill in the art.

FIG.26illustrates fluid flow paths through the motor200(FIG.26). As discussed above, the fluid entering each module is separated into a working fluid flow that energizes the secondary reciprocating motor assembly of that module and a pressure fluid flow that passes through the primary rotor shaft of that module and an exhaust flow that may have been collected from previous modules. The working fluid, after performing work, is exhausted from that module as an exhaust flow. The exhaust flow is then provided to downstream module(s) to continue to pass through the motor. The pressure fluid flow, after passing through a module, is provided to a downstream module to power the secondary reciprocating motor assembly of that downstream module. Similarly, exhaust fluid flows from upstream modules must be isolated from pressure fluid flows that have yet to perform work until all exhaust fluid can be collected at the motor exit.

As can be seen inFIG.26, an exhaust piping manifold190is assembled with subassembly191disposed within the first module100a(seeFIG.25) and subassembly192disposed within the second module100b(seeFIG.25) with the assemblies interconnected by exhaust tube193. For the two-module motor under consideration, centralizer194is disposed within the first module and as such does not collect any exhaust flows from previous modules; it does allow pressurized fluid to the downstream module and accordingly has flutes cut in its periphery to allow pressurized fluid to flow by. Pressurized fluid is delivered to the first module, performs work, is collected as exhaust fluid at centralizer195, and conveyed to exhaust tube193for pass through module2. Centralizer195also includes flutes to allow pressurized fluid to flow by to module2. Pressurized fluid is conveyed across these flutes within the primary rotor of module1and delivered to module2. Pressurized fluid is delivered to the second module proximate centralizer196, performs work, collected as exhaust fluid at centralizer197, and combined with exhaust flow in exhaust tube198and allowed to exit the motor assembly. Comparable fluid management flow manifolds can be conceived for motors consisting of more than two modules with exhaust manifolds configured for each module according to the sequential connection of the assembly.

FIGS.27and28show the rotary reciprocation of the rotary piston assembly, related ring reciprocation, and the corresponding rotor rotation.FIG.27is a partial cross section view of a motor module120at the commencement of a stroke according to an embodiment of the disclosure, with liner assembly cutaway illustrating clockwise reciprocating rotor assembly rotation at commencement of stroke. As can be seen inFIG.27, fluid is rotating the secondary reciprocating rotor assembly122in a clockwise direction A that imparts will forward linear motion B to the helical and harmonic drive rings124(driving them in the direction indicated by B) such that the harmonic drive ring124aimparts clockwise rotation C to the primary rotor assembly126.

FIG.28is a partial cross section view of a motor module according to an embodiment of the disclosure with liner assembly cutaway illustrating counter-clockwise reciprocating rotor assembly rotation at completion of a stroke. As can be seen inFIG.28, fluid is rotating the secondary reciprocating rotor assembly122in a counter-clockwise direction A′ that will impart a backward linear motion B′ to the helical and harmonic drive rings124such that the harmonic drive ring124aimparts clockwise rotation C to the primary rotor assembly126.

FIG.29Ais an illustration of a reciprocating rotary piston assembly with a stator according to the present embodiment of the disclosure. As can be seen inFIG.29A, a three-blade reciprocating rotary piston assembly is used with a three-ribbed stator.

FIG.29Bis an illustration of a four-blade reciprocating rotary piston assembly with a four-ribbed stator, resulting in 4/3 the output torque of the baseline embodiment inFIG.29Afor comparable pressure conditions. Hence, the rotor output torque can be increased by selecting the properties of the rotary piston assembly.

FIG.29Cis an illustration of a five-blade reciprocating rotary piston assembly with a five-ribbed stator, resulting in 5/3 the output torque of the baseline embodiment inFIG.29Afor comparable pressure conditions. Hence, the rotor output torque can be increased by selecting the properties of the rotary piston assembly.

Comparing chamber volumes inFIGS.29A,29B &29C, the cumulative chamber volume of each design decreases as additional stator ribs is used thereby decreasing the required fluid volume to complete reciprocation. Hence, the input flowrate characteristics of the motor can be modified by selecting the properties of the rotary piston assembly.

FIGS.30A,30B and30C, are illustrations of a helical drive assembly according to the present embodiment of the disclosure with large, nominal, and small balls, respectively, to accommodate varying circumferential strokes of the secondary rotor assembly and induced helical ring displacements.

FIG.31Ais an illustration of a harmonic drive assembly according to the present embodiment of the disclosure; the assembly is fitted with a rotor with three harmonics per revolution with a ball transfer outer race housing with six harmonics per revolution. The [3:6] configuration shown results in 180 degrees of rotor advance per ring reciprocation cycle making it preferred for rotary valve operation.

FIG.31Bis an illustration of a harmonic drive assembly according to the present embodiment of the disclosure; the assembly is fitted with a rotor with four harmonics per revolution with a ball transfer outer race housing with twelve harmonics per revolution. The [4:12] configuration shown results in 120 degrees of rotor advance per ring reciprocation cycle making it a preferred configuration for rotary valve operation.

FIG.31Cis an illustration of a harmonic drive assembly according to the present embodiment of the disclosure; the assembly is fitted with a rotor with six harmonics per revolution with a ball transfer outer race housing with twelve harmonics per revolution. The [6:12] configuration shown results in 90 degrees of rotor advance per ring reciprocation cycle making it a preferred configuration for rotary valve operation.

Comparing ring reciprocation (axial amplitude) of various harmonic drives inFIGS.31A,31B &31Cwith reciprocating rotary piston assemblies (circumferential reciprocation) inFIGS.29A,29B &29Crequires displacement compatibility via preferred selection of helical power screw properties that convert rotary piston reciprocation into axial ring displacement. Multiple configurations can be conceived by selecting the properties of the overall assembly components to achieve the desired rotor output speed and torque based upon input flow and pressure conditions. Other configurations may be realized by appropriate selection of design parameters.

Operation

The operation of a rotary piston motor is as follows. As the rotor rotates, the valves within the first valve block assembly open to allow fluid pressure and flow into chamber A of the rotary piston assembly at the upstream end. The fluid pressure drives the rotary pistons clockwise exhausting the fluid from chamber B at the downstream end. The exhaust fluid is ported around the harmonic drive assembly and directed to the exhaust ports in the lower valve block assembly. The exhaust valves allow flow from chamber B into the exhaust manifold on rotor centerline.

As the rotary pistons rotate clockwise, an output torque is delivered to the helical drive screw assembly. This clockwise rotation and torque produces ball motion in the non-reversing track and produces forward axial motion in the helical and harmonic drive rings. The helical and harmonic drive rings apply a force to the ball(s) in the reversing track of the harmonic drive and introduces clockwise rotation and torque to the output rotor.

As the rotary pistons reach the end of stroke, the pressure and exhaust valves reverse port connections and the pressurized fluid is directed to chamber B and the fluid is exhausted from chamber A. This produces counter-clockwise motion in the rotary piston output shaft and reverses the motion of the ball(s) in the helical drive screw and causes the helical and harmonic drive rings to retract. Since the ball(s) in the harmonic drive had reached the dwell point at the end of the chamber A pressurization stroke, the ball(s) in the harmonic drive is now on the reversing track of the harmonic drive. As the helical and harmonic drive rings retract during pressurization of chamber B, clockwise motion and torque are delivered to the output rotor. When the rotary piston reaches the end of stroke, the harmonic drive(s) reaches another dwell point and the cycle is complete. The cycle repeats itself with the subsequent pressurization of chamber A and exhaust of chamber B as the rotor valves return to their initial conditions following one full or fractional rotation of the rotor.

Configurations

The harmonic drive rotor includes a specified number of harmonics. The number of harmonics on the output shaft is coupled with the number of blades on the rotary piston so that the speed output of the assembly is commensurate with the rotation-generating capacity of the rotary piston assembly. That is, as the number of harmonics on the assembly increases, the rotor advance per piston cycle will decrease; this will decrease the speed of the rotor for a given flowrate through the motor. Accordingly, the number of blades on the rotary piston can likewise increase to provide increased torque at lower speeds so that the motor can run at constant rotational power with the output torque and speed tailored to preferred values. Some of the options are shown by combining the rotary piston, helical drive and harmonic drive options in the panel ofFIGS.29,30&31.

While the exemplary embodiments illustrated in the figures and described herein are presently preferred, it should be understood that these embodiments are offered by way of example only. Accordingly, the present application is not limited to a particular embodiment, but extends to various modifications that nevertheless fall within the scope of the appended claims. The order or sequence of any processes or method steps may be varied or re-sequenced according to alternative embodiments.

Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited in the claims. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Accordingly, all such modifications are intended to be included within the scope of the present application. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. In the claims, any means-plus-function clause is intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the exemplary embodiments without departing from the scope of the present application.