US20160305528A1 - Harmonic Gear Drive - Google Patents
Harmonic Gear Drive Download PDFInfo
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- US20160305528A1 US20160305528A1 US15/131,356 US201615131356A US2016305528A1 US 20160305528 A1 US20160305528 A1 US 20160305528A1 US 201615131356 A US201615131356 A US 201615131356A US 2016305528 A1 US2016305528 A1 US 2016305528A1
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- United States
- Prior art keywords
- spline
- wave generator
- output
- teeth
- input shaft
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H49/00—Other gearings
- F16H49/001—Wave gearings, e.g. harmonic drive transmissions
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B4/00—Drives for drilling, used in the borehole
- E21B4/006—Mechanical motion converting means, e.g. reduction gearings
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H49/00—Other gearings
- F16H49/001—Wave gearings, e.g. harmonic drive transmissions
- F16H2049/003—Features of the flexsplines therefor
Definitions
- the present disclosure relates generally to power transmission mechanisms and specifically to power transmission mechanisms in downhole tools.
- rotation of components relative to the rest of the drill string may be desired.
- rotation downhole is generated by a motor such as an electric motor or mud motor.
- a motor such as an electric motor or mud motor.
- the rotation rate of electric motors and mud motors may be too rapid for the desired rotation.
- one or more transmission devices may be required.
- the present disclosure provides for a harmonic gear drive.
- the harmonic gear drive may include an input shaft.
- the input shaft may be generally tubular.
- the harmonic gear drive may include a wave generator mechanically coupled to the input shaft.
- the wave generator may have a varying diameter.
- the portion of the wave generator having the largest diameter may define a major diameter of the wave generator.
- the harmonic gear drive may include a flex spline.
- the flex spline may be generally tubular and may include external teeth.
- the flex spline may be adapted to be positioned about the wave generator and to be elastically flexed thereby as the wave generator is rotated.
- the harmonic gear drive may include a fixed spline.
- the fixed spline being annular in shape and including a first number of internal teeth adapted to engage the external teeth of the flex spline aligned with the major diameter of the wave generator.
- the harmonic gear drive may include an output spline, the output spline being annular in shape and including a second number of internal teeth adapted to engage the external teeth of the flex spline aligned with the major diameter of the wave generator.
- the second number of internal teeth may be different from the first number of internal teeth.
- FIG. 1 depicts a cross section view of a harmonic gear drive consistent with at least one embodiment of the present disclosure.
- FIG. 2 depicts an exploded partial cross section view of the harmonic gear drive of FIG. 1 .
- FIG. 3 depicts a partially disassembled end view of the harmonic gear drive of FIG. 1 .
- FIG. 4 depicts a cross section view of a harmonic gear drive consistent with at least one embodiment of the present disclosure.
- harmonic gear drive 100 may mechanically couple between input shaft 101 and output sub 103 .
- Input shaft 101 may be mechanically coupled to the output shaft of a motor (not shown).
- the motor may, for example and without limitation, be a mud motor, electric motor, or any other motor suitable for use in a wellbore.
- input shaft 101 may be mechanically coupled directly to an output shaft of the motor.
- input shaft 101 may include one or more power transmission couplings that mechanically couple input shaft 101 to the output shaft of the motor.
- the transmission coupling may include castellations 105 as depicted in FIGS. 1, 2 .
- Castellations 105 may be formed in input shaft 101 and may link with castellations formed in the output shaft of the motor to allow rotational forces to be transmitted into input shaft 101 by interlocking the castellations 105 .
- Input shaft 101 may be mechanically coupled to wave generator 107 .
- input shaft 101 and wave generator 107 may be generally tubular, allowing a central bore to be formed therethrough.
- the central bore may allow, for example and without limitation, the circulation of drilling fluid therethrough.
- Wave generator 107 may be formed as an integral part of input shaft 101 .
- wave generator 107 may constitute an eccentric cam having a varying diameter.
- wave generator 107 may be generally elliptical in cross section.
- major diameter” of wave generator 107 describes the portion or portions of wave generator 107 having the largest diameter, depicted in FIG.
- D M 3 as D M .
- One having ordinary skill in the art with the benefit of this disclosure will understand that depending on the cross-sectional shape of wave generator 107 , one or more major diameters D M may be formed. “Diameter” as used with respect to a point along the outer perimeter of wave generator 107 means a line measured from the point through the center to a point on the perimeter of wave generator 107 opposite the point.
- wave generator 107 may be positioned within flex spline 109 .
- Flex spline 109 may be a generally tubular member having external teeth 111 .
- flex spline 109 may engage with fixed spline 113 and output spline 115 .
- Fixed spline 113 and output spline 115 may be annular bodies.
- Fixed spline 113 may be mechanically coupled to fixed sub 117 such that it does not rotate relative to fixed sub 117 .
- Fixed spline 113 may include internal teeth 114 adapted to engage external teeth 111 of flex spline 109 .
- Output spline 115 may be rigidly mechanically coupled to output sub 103 .
- Output spline 115 may include internal teeth 116 adapted to engage external teeth 111 of flex spline 109 .
- flex spline 109 may elastically deform in response to the rotation of wave generator 107 .
- external teeth 111 of flex spline 109 may engage internal teeth 114 of fixed spline 113 and internal teeth 116 output spline 115 where flex spline 109 is aligned with major diameter D M of wave generator 107 .
- external teeth 111 ′ are engaged with internal teeth 114 of fixed spline 113
- external teeth 111 ′′ are not.
- Wave generator 107 may slide within flex spline 109 as wave generator 107 is rotated.
- needle bearing 110 may be positioned between wave generator 107 and flex spline 109 .
- Needle bearing 110 may include a plurality of rollers or needles positioned between the surfaces of flex spline 109 and wave generator 107 and to rotate between flex spline 109 and wave generator 107 .
- Needle bearing 110 may, for example and without limitation, reduce friction between wave generator 107 and flex spline 109 as flex spline rotates around wave generator 107 .
- needle bearing 110 may, in some embodiments, include additional components such as races (not shown) without deviating from the scope of this disclosure.
- the teeth of fixed spline 113 engaged with external teeth 111 of flex spline 109 may thus precess about internal teeth 114 of fixed spline 113 as wave generator 107 is rotated.
- flex spline 109 rotates relative to fixed spline 113 based on the difference in number of teeth between flex spline 109 and fixed spline 113 .
- output spline 115 may have a different number of teeth than fixed spline 113 . In some embodiments, output spline 115 may have between 1 and 10 fewer teeth than fixed spline 113 .
- output spline 115 has a different number of teeth than fixed spline 113 , as flex spline 109 rotates within output spline 115 and the engaged external teeth 111 ′ precess about the teeth of output spline 115 , output spline 115 is rotated relative to fixed spline 113 .
- the ratio between the speed at which output spline 115 rotates relative to fixed spline 113 and the speed at which input shaft 101 rotates may be determined by the ratio of the difference in number of teeth between output spline 115 and fixed spline 113 and the number of teeth in fixed spline 113 .
- output spline 115 may rotate one tooth, or 1/160 th of a rotation for each rotation of wave generator 107 .
- output spline 115 and fixed spline 113 may include any suitable number of teeth and may have any tooth differential without deviating from the scope of this disclosure.
- output sub 103 may be a generally tubular member that mechanically couples to additional equipment (not shown), allowing the additional equipment such as components of a bottom hole assembly to rotate relative to fixed sub 117 .
- output sub 103 and fixed sub 117 may be adapted to support the rotation of input shaft 101 .
- one or more bearings 119 may be positioned between input shaft 101 and output sub 103 and/or fixed sub 117 .
- fixed sub 117 may be mechanically coupled to fixed spline 113 by, for example and without limitation, one or more fasteners including linking pin 121 as depicted in FIG. 1 .
- output spline 115 may likewise be mechanically coupled to output sub 103 by one or more fasteners such as linking pin 123 .
- flex spline 109 may include two sets of external teeth 111 , each adapted to mesh with one of the teeth of fixed spline 113 or output spline 115 .
- external teeth 111 in such an embodiment may, for example and without limitation, include different tooth geometry, spacing, or numbers.
- fixed spline 113 and output spline 115 may have the same number of teeth, while each set of external teeth 111 of flex spline 109 includes a different number of external teeth.
- input shaft 101 ′ may be formed as part of rotor 201 of electric motor 200 .
- Electric motor 200 may include outer housing 203 mechanically coupled to fixed sub 117 .
- Electric motor 200 may include stator 205 .
- Stator 205 as understood in the art, may include windings 207 positioned to induce rotating electromagnetic fields into the interior of stator 205 .
- electric motor 200 may be an induction motor.
- rotor 201 may include a plurality of windings adapted to cause rotation of rotor 201 in response to the rotating electromagnetic field induced by windings 207 .
- electric motor 200 may be a permanent magnet motor.
- rotor 201 may include a plurality of permanent magnets positioned to cause rotation of rotor 201 in response to the rotating electromagnetic field induced by windings 207 .
- bearings 119 may be sufficient to support and/or stabilize the entire length of rotor 201 , allowing electric motor 200 to operate without additional bearings. Additionally, the overall length of harmonic gear drive 100 may be reduced.
- input shaft 101 and wave generator 107 may be formed as an integral unit.
- input shaft 101 may have a wall thickness of between 3 mm and 20 mm at its narrowest point and between 5 mm and 50 mm at its widest, corresponding with the major diameter D M of wave generator 107 .
- harmonic gear drive 100 may be used in rotary steerable system (RSS) 300 , depicted schematically in FIG. 4 .
- RSS 300 may include RSS housing 301 and other components as understood in the art.
- RSS housing 301 may be mechanically coupled to output sub 103 and may be rotated relative to the rest of drill string 305 .
- driveshaft 303 may be passed through the interior of input shaft 101 .
- the diameter of driveshaft 303 able to be used with harmonic gear drive 100 may depend on the interior diameter of input shaft 101 .
- the diameter of driveshaft 303 may be maximized for a given outer diameter of harmonic gear drive 100 .
Abstract
A harmonic gear drive includes an input shaft and an output shaft. The input shaft is mechanically coupled to a wave generator which has a varying diameter. The wave generator is positioned within a flex spline which includes external teeth. The external teeth of the flex spline engage with internal teeth of a fixed spline and an output spline when the major diameter of the wave generator is aligned therewith. The output spline has a different number of teeth from the input spline such that, as the wave generator is rotated and the flex spline rotates, the output spline is rotated relative to the fixed spline.
Description
- This application is a nonprovisional application which claims priority from U.S. provisional application No. 62/150,101, filed Apr. 20, 2015, the entirety of which is hereby incorporated by reference.
- The present disclosure relates generally to power transmission mechanisms and specifically to power transmission mechanisms in downhole tools.
- In a wellbore, rotation of components relative to the rest of the drill string may be desired. Typically, rotation downhole is generated by a motor such as an electric motor or mud motor. However, the rotation rate of electric motors and mud motors may be too rapid for the desired rotation. When a relatively slow rotation relative to the rest of the drill string is desired, one or more transmission devices may be required.
- The present disclosure provides for a harmonic gear drive. The harmonic gear drive may include an input shaft. The input shaft may be generally tubular. The harmonic gear drive may include a wave generator mechanically coupled to the input shaft. The wave generator may have a varying diameter. The portion of the wave generator having the largest diameter may define a major diameter of the wave generator. The harmonic gear drive may include a flex spline. The flex spline may be generally tubular and may include external teeth. The flex spline may be adapted to be positioned about the wave generator and to be elastically flexed thereby as the wave generator is rotated. The harmonic gear drive may include a fixed spline. The fixed spline being annular in shape and including a first number of internal teeth adapted to engage the external teeth of the flex spline aligned with the major diameter of the wave generator. The harmonic gear drive may include an output spline, the output spline being annular in shape and including a second number of internal teeth adapted to engage the external teeth of the flex spline aligned with the major diameter of the wave generator. The second number of internal teeth may be different from the first number of internal teeth.
- The present disclosure is best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
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FIG. 1 depicts a cross section view of a harmonic gear drive consistent with at least one embodiment of the present disclosure. -
FIG. 2 depicts an exploded partial cross section view of the harmonic gear drive ofFIG. 1 . -
FIG. 3 depicts a partially disassembled end view of the harmonic gear drive ofFIG. 1 . -
FIG. 4 depicts a cross section view of a harmonic gear drive consistent with at least one embodiment of the present disclosure. - It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
- As depicted in
FIGS. 1, 2 ,harmonic gear drive 100 may mechanically couple betweeninput shaft 101 andoutput sub 103.Input shaft 101 may be mechanically coupled to the output shaft of a motor (not shown). The motor may, for example and without limitation, be a mud motor, electric motor, or any other motor suitable for use in a wellbore. In some embodiments,input shaft 101 may be mechanically coupled directly to an output shaft of the motor. In some embodiments,input shaft 101 may include one or more power transmission couplings that mechanically coupleinput shaft 101 to the output shaft of the motor. For example and without limitation, in some embodiments, the transmission coupling may includecastellations 105 as depicted inFIGS. 1, 2 .Castellations 105 may be formed ininput shaft 101 and may link with castellations formed in the output shaft of the motor to allow rotational forces to be transmitted intoinput shaft 101 by interlocking thecastellations 105. -
Input shaft 101 may be mechanically coupled towave generator 107. In some embodiments,input shaft 101 andwave generator 107 may be generally tubular, allowing a central bore to be formed therethrough. In some embodiments in whichharmonic gear drive 100 is used as part of a downhole tool, the central bore may allow, for example and without limitation, the circulation of drilling fluid therethrough.Wave generator 107 may be formed as an integral part ofinput shaft 101. In some embodiments,wave generator 107 may constitute an eccentric cam having a varying diameter. For example, as depicted inFIG. 3 ,wave generator 107 may be generally elliptical in cross section. As used herein, “major diameter” ofwave generator 107 describes the portion or portions ofwave generator 107 having the largest diameter, depicted inFIG. 3 as DM. One having ordinary skill in the art with the benefit of this disclosure will understand that depending on the cross-sectional shape ofwave generator 107, one or more major diameters DM may be formed. “Diameter” as used with respect to a point along the outer perimeter ofwave generator 107 means a line measured from the point through the center to a point on the perimeter ofwave generator 107 opposite the point. - As depicted in
FIGS. 1, 2 ,wave generator 107 may be positioned withinflex spline 109.Flex spline 109 may be a generally tubular member havingexternal teeth 111. In some embodiments,flex spline 109 may engage withfixed spline 113 andoutput spline 115. Fixedspline 113 andoutput spline 115 may be annular bodies. Fixedspline 113 may be mechanically coupled tofixed sub 117 such that it does not rotate relative tofixed sub 117. Fixedspline 113 may includeinternal teeth 114 adapted to engageexternal teeth 111 offlex spline 109.Output spline 115 may be rigidly mechanically coupled tooutput sub 103.Output spline 115 may includeinternal teeth 116 adapted to engageexternal teeth 111 offlex spline 109. - In some embodiments,
flex spline 109 may elastically deform in response to the rotation ofwave generator 107. In some embodiments,external teeth 111 offlex spline 109 may engageinternal teeth 114 offixed spline 113 andinternal teeth 116output spline 115 whereflex spline 109 is aligned with major diameter DM ofwave generator 107. As depicted inFIG. 3 ,external teeth 111′ are engaged withinternal teeth 114 offixed spline 113, whereasexternal teeth 111″ are not.Wave generator 107 may slide withinflex spline 109 aswave generator 107 is rotated. In some embodiments, needle bearing 110 may be positioned betweenwave generator 107 andflex spline 109. Needle bearing 110 may include a plurality of rollers or needles positioned between the surfaces offlex spline 109 andwave generator 107 and to rotate betweenflex spline 109 andwave generator 107. Needle bearing 110 may, for example and without limitation, reduce friction betweenwave generator 107 andflex spline 109 as flex spline rotates aroundwave generator 107. As understood in the art,needle bearing 110 may, in some embodiments, include additional components such as races (not shown) without deviating from the scope of this disclosure. As understood in the art, the teeth of fixedspline 113 engaged withexternal teeth 111 offlex spline 109 may thus precess aboutinternal teeth 114 of fixedspline 113 aswave generator 107 is rotated. - As the engaged
external teeth 111′ precess,flex spline 109 rotates relative to fixedspline 113 based on the difference in number of teeth betweenflex spline 109 and fixedspline 113. - As described above with respect to fixed
spline 113,external teeth 111′ (aligned with major diameter DM of wave generator 107) are likewise engaged withinternal teeth 116 ofoutput spline 115. In some embodiments,output spline 115 may have a different number of teeth than fixedspline 113. In some embodiments,output spline 115 may have between 1 and 10 fewer teeth than fixedspline 113. Becauseoutput spline 115 has a different number of teeth than fixedspline 113, asflex spline 109 rotates withinoutput spline 115 and the engagedexternal teeth 111′ precess about the teeth ofoutput spline 115,output spline 115 is rotated relative to fixedspline 113. The ratio between the speed at whichoutput spline 115 rotates relative to fixedspline 113 and the speed at whichinput shaft 101 rotates may be determined by the ratio of the difference in number of teeth betweenoutput spline 115 and fixedspline 113 and the number of teeth in fixedspline 113. For example, in an embodiment in which fixedspline 113 includes 160 teeth andoutput spline 115 includes 159,output spline 115 may rotate one tooth, or 1/160th of a rotation for each rotation ofwave generator 107. Thus, such aharmonic gear drive 100 may have a gear-reduction ration of 160:1 betweeninput shaft 101 andoutput sub 103. One having ordinary skill in the art with the benefit of this disclosure will understand thatoutput spline 115 and fixedspline 113 may include any suitable number of teeth and may have any tooth differential without deviating from the scope of this disclosure. - In some embodiments, as depicted in
FIGS. 1, 2 ,output sub 103 may be a generally tubular member that mechanically couples to additional equipment (not shown), allowing the additional equipment such as components of a bottom hole assembly to rotate relative to fixedsub 117. In some embodiments,output sub 103 and fixedsub 117 may be adapted to support the rotation ofinput shaft 101. In some embodiments, one ormore bearings 119 may be positioned betweeninput shaft 101 andoutput sub 103 and/or fixedsub 117. - In some embodiments, fixed
sub 117 may be mechanically coupled to fixedspline 113 by, for example and without limitation, one or more fasteners including linkingpin 121 as depicted inFIG. 1 . In some embodiments,output spline 115 may likewise be mechanically coupled tooutput sub 103 by one or more fasteners such as linkingpin 123. - As understood by one having ordinary skill in the art with the benefit of this disclosure, the difference in number of teeth between fixed
spline 113 andoutput spline 115 may be limited by the need for the teeth to properly mesh withexternal teeth 111 offlex spline 109. In some embodiments,flex spline 109 may include two sets ofexternal teeth 111, each adapted to mesh with one of the teeth of fixedspline 113 oroutput spline 115. As understood in the art,external teeth 111 in such an embodiment may, for example and without limitation, include different tooth geometry, spacing, or numbers. In some embodiments in which different sets ofexternal teeth 111 are used with fixedspline 113 andoutput spline 115, fixedspline 113 andoutput spline 115 may have the same number of teeth, while each set ofexternal teeth 111 offlex spline 109 includes a different number of external teeth. - In some embodiments, as depicted in
FIG. 4 ,input shaft 101′ may be formed as part ofrotor 201 ofelectric motor 200.Electric motor 200 may includeouter housing 203 mechanically coupled to fixedsub 117.Electric motor 200 may includestator 205.Stator 205, as understood in the art, may includewindings 207 positioned to induce rotating electromagnetic fields into the interior ofstator 205. In some embodiments,electric motor 200 may be an induction motor. In such an embodiment,rotor 201 may include a plurality of windings adapted to cause rotation ofrotor 201 in response to the rotating electromagnetic field induced bywindings 207. In some embodiments,electric motor 200 may be a permanent magnet motor. In such an embodiment,rotor 201 may include a plurality of permanent magnets positioned to cause rotation ofrotor 201 in response to the rotating electromagnetic field induced bywindings 207. - In some embodiments, by forming
input shaft 101′ as a part ofrotor 201, backlash may be reduced or eliminated. In some embodiments,bearings 119 may be sufficient to support and/or stabilize the entire length ofrotor 201, allowingelectric motor 200 to operate without additional bearings. Additionally, the overall length ofharmonic gear drive 100 may be reduced. - In some embodiments,
input shaft 101 andwave generator 107 may be formed as an integral unit. In some embodiments,input shaft 101 may have a wall thickness of between 3 mm and 20 mm at its narrowest point and between 5 mm and 50 mm at its widest, corresponding with the major diameter DM ofwave generator 107. - In some embodiments,
harmonic gear drive 100 may be used in rotary steerable system (RSS) 300, depicted schematically inFIG. 4 .RSS 300 may includeRSS housing 301 and other components as understood in the art.RSS housing 301 may be mechanically coupled tooutput sub 103 and may be rotated relative to the rest ofdrill string 305. In some embodiments,driveshaft 303 may be passed through the interior ofinput shaft 101. In such an embodiment, the diameter ofdriveshaft 303 able to be used withharmonic gear drive 100 may depend on the interior diameter ofinput shaft 101. In some embodiments, by forminginput shaft 101 as a generally thin-walled member, the diameter ofdriveshaft 303 may be maximized for a given outer diameter ofharmonic gear drive 100. - The foregoing outlines features of several embodiments so that a person of ordinary skill in the art may better understand the aspects of the present disclosure. Such features may be replaced by any one of numerous equivalent alternatives, only some of which are disclosed herein. One of ordinary skill in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. One of ordinary skill in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.
Claims (28)
1. A harmonic gear drive comprising:
an input shaft;
a wave generator mechanically coupled to the input shaft, the wave generator having a varying diameter, the portion of the wave generator having the largest diameter defining a major diameter of the wave generator;
a flex spline, the flex spline being generally tubular and including external teeth, the flex spline positioned about the wave generator;
a fixed spline, the fixed spline being including a first number of internal teeth that engages the external teeth of the flex spline aligned with the major diameter of the wave generator; and
an output spline, the output spline including a second number of internal teeth adapted to engage the external teeth of the flex spline aligned with the major diameter of the wave generator, the second number of internal teeth being different from the first number of internal teeth.
2. The harmonic gear drive of claim 1 , further comprising an output sub mechanically coupled to the output spline.
3. The harmonic gear drive of claim 2 , further comprising at least one bearing between the output sub and the input shaft.
4. The harmonic gear drive of claim 1 , wherein the input shaft is mechanically coupled to an output shaft of a motor.
5. The harmonic gear drive of claim 4 , wherein the motor is a mud motor or electric motor.
6. The harmonic gear drive of claim 5 , wherein the input shaft is formed as part of a rotor of the motor.
7. The harmonic gear drive of claim 4 , wherein the input shaft further comprises a transmission coupling to mechanically couple the input shaft to the output shaft of the motor.
8. The harmonic gear drive of claim 7 , wherein the transmission coupling comprises a castellation formed on the input shaft and a corresponding castellation formed on the output shaft of the motor.
9. The harmonic gear drive of claim 4 , further comprising a fixed sub, the fixed sub mechanically coupled to the fixed spline and the motor.
10. The harmonic gear drive of claim 9 , further comprising at least one bearing between the fixed sub and the input shaft.
11. The harmonic gear drive of claim 1 , wherein the wave generator is generally elliptical in cross section.
12. The harmonic gear drive of claim 1 , wherein the difference between the first number of teeth and the second number of teeth is between 1 and 10.
13. The harmonic gear drive of claim 1 , wherein the external teeth of the flex spline comprise a first set of teeth and a second set of teeth, the first set of teeth engaging the internal teeth of the fixed spline and the second set of teeth engaging the internal teeth of the output spline.
14. The harmonic gear drive of claim 1 , further comprising a needle bearing positioned between the flex spline and the wave generator.
15. The harmonic gear drive of claim 1 , wherein the input shaft, wave generator, flex spline, fixed spline, and output spline are generally tubular having a central bore formed therethrough.
16. The harmonic gear drive of claim 15 , further comprising a drive shaft extending through the central bore.
17. The harmonic gear drive of claim 1 , wherein the output sub is coupled to an RSS housing of an RSS.
18. The harmonic gear drive of claim 1 , wherein the wave generator is an eccentric cam.
19. The harmonic gear drive of claim 1 , wherein the wave generator is generally elliptical in cross section.
20. A method comprising:
providing a harmonic gear drive including:
an input shaft;
a wave generator mechanically coupled to the input shaft, the wave generator having a varying diameter, the portion of the wave generator having the largest diameter defining a major diameter of the wave generator;
a flex spline, the flex spline being generally tubular and including external teeth, the flex spline positioned about the wave generator;
a fixed spline, the fixed spline being including a first number of internal teeth that engages the external teeth of the flex spline aligned with the major diameter of the wave generator; and
an output spline, the output spline including a second number of internal teeth adapted to engage the external teeth of the flex spline aligned with the major diameter of the wave generator, the second number of internal teeth being different from the first number of internal teeth;
engaging the teeth of the flex spline with the internal teeth of the fixed spline and the output spline;
elastically deforming the flex spline with the wave generator such that at least one tooth of the flex spline engages the internal teeth of the fixed spline and the output spline;
rotating the wave generator such that the flex spline is elastically deformed while remaining engaged with the internal teeth of the fixed spline and the output spline such that the output spline rotates relative to the fixed spline.
21. The method of claim 20 , wherein the input shaft is coupled to an output shaft of a motor, and the method further comprises rotating the input shaft with the motor.
22. The method of claim 21 , wherein the input shaft is coupled to the output shaft of the motor by a transmission coupling, the transmission coupling comprising a castellation formed on the input shaft and a corresponding castellation formed on the output shaft of the motor, and the method further comprises interlocking the castellations.
23. The method of claim 20 , wherein the input shaft, wave generator, flex spline, fixed spline, and output spline are generally tubular having a central bore formed therethrough.
24. The method of claim 20 , wherein the wave generator is generally elliptical in cross section.
25. The method of claim 20 , further comprising:
providing a needle bearing between the wave generator and the flex spline; and
reducing friction between the wave generator and the flex spline as the wave generator is rotated.
26. The method of claim 20 , wherein the output spline is rotated at a speed different than the input shaft.
27. The method of claim 26 , wherein the ratio between the speed at which the output spline rotates and the speed at which the input shaft rotates is determined by the ratio of the difference in number of teeth between the output spline and the fixed spline and the number of teeth on the flex spline.
28. A rotary steerable system comprising:
a harmonic gear drive comprising:
an input shaft;
a wave generator mechanically coupled to the input shaft, the wave generator having a varying diameter, the portion of the wave generator having the largest diameter defining a major diameter of the wave generator;
a flex spline, the flex spline being generally tubular and including external teeth, the flex spline positioned about the wave generator;
a fixed spline, the fixed spline being including a first number of internal teeth that engages the external teeth of the flex spline aligned with the major diameter of the wave generator; and
an output spline, the output spline including a second number of internal teeth adapted to engage the external teeth of the flex spline aligned with the major diameter of the wave generator, the second number of internal teeth being different from the first number of internal teeth;
a motor having an output shaft mechanically coupled to the input shaft;
an RSS housing mechanically coupled to the output spline; and
a drive shaft extending through an interior of the harmonic gear drive and the RSS housing.
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US15/131,356 US20160305528A1 (en) | 2015-04-20 | 2016-04-18 | Harmonic Gear Drive |
EP16166167.3A EP3085994A1 (en) | 2015-04-20 | 2016-04-20 | Harmonic gear drive |
US16/383,282 US11168521B2 (en) | 2015-04-20 | 2019-04-12 | Harmonic gear drive |
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US15/131,356 US20160305528A1 (en) | 2015-04-20 | 2016-04-18 | Harmonic Gear Drive |
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US (2) | US20160305528A1 (en) |
EP (1) | EP3085994A1 (en) |
Cited By (5)
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DE102016210864A1 (en) * | 2016-06-17 | 2017-09-07 | Schaeffler Technologies AG & Co. KG | actuator |
EP3425777A3 (en) * | 2017-07-07 | 2019-05-08 | Hamilton Sundstrand Corporation | Compound harmonic gear |
US20190234503A1 (en) * | 2015-04-20 | 2019-08-01 | Nabors Lux 2 Sarl | Harmonic Gear Drive |
CN113443153A (en) * | 2021-07-22 | 2021-09-28 | 成都浩孚科技有限公司 | Photoelectric pod transmission structure |
US11274736B2 (en) * | 2017-03-17 | 2022-03-15 | Sumitomo Heavy Industries, Ltd. | Bending meshing type gear device |
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US11814914B1 (en) * | 2022-06-16 | 2023-11-14 | Halliburton Energy Services, Inc. | Downhole tractor drive module |
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US20160305528A1 (en) * | 2015-04-20 | 2016-10-20 | Nabors Lux Finance 2 Sarl | Harmonic Gear Drive |
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2016
- 2016-04-18 US US15/131,356 patent/US20160305528A1/en not_active Abandoned
- 2016-04-20 EP EP16166167.3A patent/EP3085994A1/en not_active Withdrawn
-
2019
- 2019-04-12 US US16/383,282 patent/US11168521B2/en active Active
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Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20190234503A1 (en) * | 2015-04-20 | 2019-08-01 | Nabors Lux 2 Sarl | Harmonic Gear Drive |
US11168521B2 (en) * | 2015-04-20 | 2021-11-09 | Nabors Lux 2 Sarl | Harmonic gear drive |
DE102016210864A1 (en) * | 2016-06-17 | 2017-09-07 | Schaeffler Technologies AG & Co. KG | actuator |
US11274736B2 (en) * | 2017-03-17 | 2022-03-15 | Sumitomo Heavy Industries, Ltd. | Bending meshing type gear device |
EP3425777A3 (en) * | 2017-07-07 | 2019-05-08 | Hamilton Sundstrand Corporation | Compound harmonic gear |
US10883590B2 (en) | 2017-07-07 | 2021-01-05 | Hamilton Sunstrand Corporation | Compound harmonic gear |
CN113443153A (en) * | 2021-07-22 | 2021-09-28 | 成都浩孚科技有限公司 | Photoelectric pod transmission structure |
Also Published As
Publication number | Publication date |
---|---|
EP3085994A1 (en) | 2016-10-26 |
US20190234503A1 (en) | 2019-08-01 |
US11168521B2 (en) | 2021-11-09 |
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