A semi-differential swerve drive

Abstract

The present disclosure relates to a semi-differential swerve drive adapted for driving a moving apparatus. The semi-differential swerve drive primarily comprises a force translation member, a core having a turning wheel portion and an axle mounting portion, a drive wheel, an axle mounted on the axle mounting portion and a locomotion wheel mounted to the axle. In use, the semi-differential swerve drive provides mobility to an object in various restricted environments.

Description

[0001] A SEMI-DIFFERENTIAL SWERVE DRIVE

[0002] Field of the Invention

[0003] [1] The present invention relates to a semi-differential swerve drive, and in particular to a drive serving as a means for locomotion of a robotic device.

[0004] [2] The invention has been developed primarily for use in locomotion and will be described hereinafter with reference to this application. It will, however, be appreciated that the invention is not limited to this particular field of use.

[0005] Background of the Invention

[0006] [3] Swerve drives are made of combination of components that can be installed to various parts of a robot or other moving apparatuses to provide mobility. Swerve drives are usually used to provide all wheels of the robot or the moving apparatus independent steering and driving from each other. This allows the robot to move in non-traditional manners such as strafing sideways or diagonally or to spin on one spot, etc.

[0007] [4] Where a robot is designed to operate in a restricted environment, such as within a pipeline, the height of the design and construction of prior art swerve drives can lead to tradeoffs in the diameter of the locomotive wheel that can be used.

[0008] [5] Furthermore, prior art swerve drives comprise a large number of components which make the swerve drive unnecessarily heavy and prone to damage.

[0009] [6] The present invention seeks to provide a semi-differential swerve drive which will overcome or substantially ameliorate at least some of the deficiencies of the prior art, or to at least provide an alternative.

[0010] [7] It is to be understood that, if any prior art information is referred to herein, such reference does not constitute an admission that the information forms part of the common general knowledge in the art, in Australia or any other country.

[0011] Summary of the Invention

[0012] [8] According to a first aspect of the present invention, a semi-differential swerve drive for driving a moving apparatus is provided, the semi-differential swerve drive comprising: a force translation member comprising a member aperture, the centre of the member aperture defining a first axis through the member aperture; - a core comprising:

[0013] (i) a turning wheel portion, adapted to be driven around the first axis

[0014] (ii) an axle mounting portion adapted to rotationally receive an axle wherein the core extends through the member aperture, such that the turning wheel portion is located to a first side of the force translation member and the axle mounting portion is located to a second side of the force translation member;

[0015] - a drive wheel rotatably mounted between the second side of the force translation member and the axle mounting portion, the drive wheel surrounding the core in at least one plane and adapted to be driven about the first axis;

[0016] - an axle rotationally mounted on the axle mounting portion;

[0017] - a locomotion wheel mounted to the axle and in rotational engagement with the axle; and wherein the semi-differential swerve drive is adapted to translate torque from the drive wheel to the axle.

[0018] [9] Advantageously, this construction can locate various wheel control components in a surrounding configuration of at least a portion of the locomotion wheel such that a larger diameter of the locomotion wheel can be used without increasing the overall height of the semi-differential swerve drive.

[0019]

[0010] In one embodiment, the drive wheel is adapted to be driven about the first axis and comprises a driving bevel gear and the axle comprises at least one driven bevel gear rotationally fixed to the axle and in meshing engagement with the driving bevel gear.

[0020]

[0011] In one embodiment, at least a portion of the locomotion wheel extends within the core into an internal volume of the drive wheel.

[0021]

[0012] Advantageously, this arrangement of the drive wheel allows the size of the locomotion wheel to be increased since the locomotion wheel can have a larger diameter such that a portion of it can be accommodated within the internal diameter of the drive wheel without its rotation being obstructed by the drive wheel.

[0022]

[0013] In one embodiment, at least a portion of the wheel that extends within the core into an internal volume of the drive wheel also extends into the member aperture.

[0023]

[0014] In one embodiment, at least a portion of the wheel that extends within the core into an internal volume of the drive wheel also extends into an internal volume of the turning wheel portion.

[0015] Advantageously, this arrangement of the drive wheel may further increase the diameter of the locomotion wheel since a larger portion of the locomotion wheel can be accommodated within the core, drive wheel and the turning wheel portion without its rotation being obstructed by the core, drive wheel and turning wheel portion.

[0024]

[0016] In one embodiment, the semi-differential swerve drive further comprises a first stator and wherein the drive wheel comprises a first rotor.

[0025]

[0017] In one embodiment, the first stator is in fixed engagement with the force translation member, and located to its second side, and surrounds the core, and the first rotor surrounds the first stator to provide a drive electric motor, such that when a current is applied to the first stator the first rotor rotates around the core, causing the axle to rotate.

[0026]

[0018] In one embodiment, the drive wheel is adapted to be driven about the first axis and comprises a driving bevel gear and the axle comprises at least one driven bevel gear rotationally fixed to the axle and in meshing engagement with the driving bevel gear and the first rotor is in fixed engagement with the driving bevel gear.

[0027]

[0019] In one embodiment, the semi-differential swerve drive further comprises a second stator in fixed engagement with the force translation member and located to its first side, and wherein the turning wheel portion comprises a second rotor.

[0028]

[0020] In one embodiment, the second stator surrounds the second rotor, and the second rotor surrounds and is in fixed engagement with the core to provide a turn electric motor, such that when a current is applied to the second stator the core rotates in relation to the force translation member.

[0029]

[0021] In one embodiment, the force translation member comprises a second side facing hollow spigot through which the core extends and the first stator extends around an outer surface of the second side facing hollow spigot.

[0030]

[0022] In one embodiment, the force translation member comprises a first side facing hollow spigot and the second stator extends around a portion of an inner surface of the first side facing hollow spigot.

[0031]

[0023] In one embodiment, the semi-differential swerve drive further comprises one or more friction reduction arrangements located at one or more locations from the following group of locations:

[0032] (i) between the axle and the axle mounting portion on each side of the locomotion wheel; (ii) between a first side surface of the force translation member and an upper surface of the turning wheel portion;

[0033] (iii) between a second side surface of the force translation member and a lower surface of the drive wheel;

[0034] (iv) between the core and the force translation member; and

[0035] (v) between the core and the drive wheel portion.

[0036]

[0024] In one embodiment, an outer circumferential surface of the turning wheel portion comprises a plurality of worm contact teeth adapted to be driven by a worm screw.

[0037]

[0025] Advantageously, the turning wheel portion is non-back-driveable.

[0038]

[0026] In one embodiment, an outer circumferential surface of the drive wheel comprises a plurality of worm contact teeth adapted to be driven by a worm screw.

[0039]

[0027] Advantageously, the drive wheel is non-back-driveable.

[0040]

[0028] In one embodiment, the axle further comprises at least one idle bevel gear rotationally mounted to the axle and in meshing engagement with the driving bevel gear.

[0041]

[0029] In one embodiment, the force translation member is adapted for attachment to the moving apparatus.

[0042]

[0030] This invention may also be said broadly to comprise in the parts, elements, and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more of said parts, elements, or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth.

[0043]

[0031] To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.

[0044]

[0032] Other aspects of the invention are also disclosed. Brief Description of the Drawings

[0045]

[0033] Notwithstanding any other forms which may fall within the scope of the present invention, preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0046]

[0034] Figure 1 shows an isometric perspective view of a first embodiment of a semidifferential swerve drive with a top portion of an axle mounting portion not shown;

[0047]

[0035] Figure 2 shows a side cross-sectional view through the centre plane of the locomotion wheel of the semi-differential swerve drive of Fig. 1 ;

[0048]

[0036] Figure 3 shows a front cross-sectional view of the semi-differential swerve drive of Fig. 1 ;

[0049]

[0037] Figure 4 shows an isometric perspective exploded view of the semi-differential swerve drive of Fig. 1 with a top portion of an axle mounting portion not shown;

[0050]

[0038] Figure 5 shows a front cross-sectional view of a second embodiment of a semidifferential swerve drive;

[0051]

[0039] Figure 6 shows a perspective exploded view of the semi-differential swerve drive of Fig. 5 with a top portion of an axle mounting portion not shown;

[0052]

[0040] Figure 7 shows an isometric perspective view of a third embodiment of a semidifferential swerve drive;

[0053]

[0041] Figure 8 shows a Front cross-sectional view of the semi-differential swerve drive of Fig. 7;

[0054]

[0042] Figure 9 shows a side cross-secrtional view of the semi-differential swerve drive of Fig. 7; and

[0055]

[0043] Figure 10 shows an isometric perspective exploded view of the semi-differential swerve drive of Fig. 7 .

[0056] Description of Embodiments

[0057]

[0044] It should be noted in the following description that like or the same reference numerals in different embodiments denote the same or similar features.

[0058]

[0045] A first embodiment of a semi-differential swerve drive is shown as 1000 in Figs. 1-4. The semi-differential swerve drive 1000 comprises a force translation member 1001 . The force translation member 1001 comprises a first hollow cylindrical region 1002 and a second hollow cylindrical region 1003 wherein the first hollow cylindrical region 1002 has a larger diameter than the second hollow cylindrical region 1003. A seating portion 1004 is located on a first end of the first hollow cylindrical region, the seating portion 1004 radially extending from an inner radius of the first hollow cylindrical region 1002 towards an outer radius of the second hollow cylindrical region 1003. The second hollow cylindrical region 1003 is connected to the seating portion of the first hollow cylindrical region 1002 such that an axis of the second hollow cylindrical region 1003 is aligned with an axis of the first hollow cylindrical region 1002, the axis being defined as axis A as shown in Fig. 2-4, and the second hollow cylindrical region 1003 defines a through-hole through the seating portion 1004. The seating portion 1004 is generally planar and perpendicular to the axis A. The seating portion 1004 has a first surface

[0059] 1005 and a second surface 1006, the first surface 1005 facing the first hollow cylindrical region and the second surface 1006 facing the second hollow cylindrical region 1003.

[0060]

[0046] According to present embodiment, the force translation member 1001 further comprises at least one mounting portion 3004 adapted for attaching the semi-differential swerve drive to a moving apparatus. Each mounting portion 3004 extends radially outward from a portion of an outer circumferential surface of the first hollow cylindrical region 1002.

[0061]

[0047] The semi-differential swerve drive 1000 further comprises a core assembly 1007. In the embodiment as shown in Figs. 2-4, the core assembly 1007 comprises a turning wheel portion 1008, an axle mounting portion 1009, and a central portion 1010. The central portion 1010 is substantially cylindrical in shape and extends axially through the first hollow cylindrical region and the second hollow cylindrical region 1003 of the force translation member 1001 along the axis A (see Figs. 2-4). The turning wheel portion 1008 is at a first end of the central portion 1010 and is located within the first hollow cylindrical region 1002 of the force translation member 1001 such that at least a portion of the turning wheel portion 1008 seats on at least a portion of the first surface 1005 of the seating portion 1004. The axle mounting portion 1009 is at a second end of the central portion 1010, wherein the second end of the central portion 1010 protrudes out of the second hollow cylindrical region.

[0062]

[0048] The turning wheel portion 1008 further comprises a turn inrunner rotor 1011. The turn inrunner rotor 1011 is substantially cylindrical and hollow in shape that defines a central through-aperture through which at least a portion of the turning wheel portion 1008 fits, the central through-aperture defining an inner circumferential surface 1012 of the turn inrunner rotor 1011. The turn inrunner rotor 101 1 is located within the first hollow cylindrical region 1002, the turn inrunner rotor 1011 surrounding at least a portion of the turning wheel portion

[0063] 1006 such that the inner circumferential surface 1012 of the turn inrunner rotor 1011 is in fixed engagement with at least a portion of the turning wheel portion 1006. The semi-differential swerve drive also comprises a turn inrunner stator 1013 that is adapted for driving the turn inrunner rotor 1011. The inrunner stator 1013 is substantially cylindrical and hollow in shape that defines a central through-aperture through which the inrunner rotor 1011 fits. The inrunner stator is located within the first hollow cylindrical region 1002 such that an outer circumferential surface 1014 of the inrunner stator 1013 is in fixed engagement with in an inner circumferential surface of the first hollow cylindrical region 1002. In an embodiment as shown in Figs. 2-3, a locating portion 1015 is provided along at least a portion of the inner circumferential surface of the first hollow region 1002 wherein the locating portion 1015 is configured to mechanically interlock or fixedly engage with the outer circumferential surface 1014 of the inrunner stator 1013. In an alternative embodiment, the locating portion 1015 is configured for simply seating the outer circumferential surface 1014 of the inrunner stator 1013. In alternative embodiments not shown, an upper circumferential surface of the inrunner stator 1013 is in fixed engagement with the first surface 1005 of the seating portion 1004. In another alternative embodiment not shown, the outer circumferential surface 1014 of the inrunner stator 1013 is fixedly engaged to at least a portion of the inner circumferential surface of the first hollow region 1002 by means of adhesive.

[0064]

[0049] The semi-differential swerve drive further comprises a drive wheel 1016. Referring to Figs. 2 and 3, the drive wheel has a drive wheel hollow cylindrical region 1017 and an annular region 1018 wherein the annular region 1018 defines a central through hole that has an inner radius 1032 smaller than the inner radius 1033 of the drive wheel hollow cylindrical region

[0065] 1017. The annular region 1018 is located and connected to an upper end of the drive wheel hollow cylindrical region 1017 such that the axis of annular region 1018 is aligned with the axis of the hollow cylindrical region 1017 and that the annular region 1018 and hollow cylindrical region 1017 share the same outer circumferential surface. The drive wheel 1016 is rotatably mounted in between at least a top region of the axle mounting portion 1009 and the second surface 1006 of the seating portion 1004 such that the axis of the driving wheel 1016 is aligned along axis A, the second hollow cylindrical region 1003 and at least a portion of the central portion 1010 is enclosed within the drive wheel hollow cylindrical region 1017, and at least a portion of the axle mounting portion 1009 is surrounded by an inner circumferential surface of the annular region 1018.

[0066]

[0050] The drive wheel also comprises a plurality of bevel gear teeth 1021. The plurality of bevel gear teeth 1021 are located along a portion of the upper surface of the annular region

[0067] 1018.

[0068]

[0051] The semi-differential swerve drive 1000 comprises a drive outrunner stator 1019. The drive outrunner stator 1019 is substantially cylindrical and hollow in shape that defines a central through aperture and an inner circumferential surface. The drive outrunner stator 1019 is located within the drive wheel hollow cylindrical region 1017 such that the inner circumferential surface of the drive outrunner stator 1019 is in fixed engagement with the outer circumferential surface of the second hollow cylindrical region 1003 of the force translation plate 1001. In an alternative embodiment, a lower surface of the drive outrunner stator 1019 is in fixed engagement with the second surface 1006 of the seating portion 1004.

[0069]

[0052] The drive wheel 1016 further comprises a drive outrunner rotor 1020 that is adapted to be driven by the drive outrunner stator 1019. The drive outrunner rotor 1020 is substantially cylindrical and hollow in shape that defines a central through aperture. The drive outrunner rotor 1020 is located within the drive wheel hollow cylindrical region 1017 such that the drive outrunner rotor 1020 surrounds the drive outrunner stator 1019, and an outer circumferential surface of the drive outrunner rotor 1020 is in fixed engagement with an inner circumferential surface 1033 of the drive wheel hollow cylindrical region 1017. In an alternative embodiment, an upper base surface of the drive outrunner rotor is in fixed engagement with a lower surface of the annular region 1018.

[0070]

[0053] The semi-differential swerve drive 1000 comprises an axle 1026 and a locomotion wheel 1022 assembly. The axle 1026 is rotationally mounted within two axle mounting apertures 1023 (top portion of the axle mounting portion not shown) on the axle mounting portion 1009 such that the axle is substantially perpendicular with the axis A. The locomotion wheel 1022 comprises an axle aperture 1023 through which the axle 1026 is inserted such that the locomotion wheel is mounted and in fixed engagement with the axle 1026 and the locomotion wheel is symmetrically aligned along the axis A as shown in Figs. 2 and 3 in use.

[0071]

[0054] Preferably, at least a portion of the locomotion wheel 1022 extends within the core 1005 into an internal volume of the drive wheel 1016. In an alternative embodiment, at least a portion of the locomotion wheel 1022 also extends into a portion of the second hollow cylindrical region 1003 of the force translation member 1001 . In another alternative embodiment, at least a portion of the locomotion wheel extends into a portion of the first hollow cylindrical region 1002 of the force translation member 1001 . In another alternative embodiment, at least a portion of the locomotion wheel extends into an internal volume of the turning wheel portion 1008. In a specific embodiment as shown in Fig. 3, the axle mounting portion 1009 comprises a divot portion 1031. At least a portion of the locomotion wheel 1022 extends to near the divot portion 1031 so that the locomotion wheel 1022 is freely rotatable around the axis of the axle without being obstructed by the axle mounting portion 1009. In another embodiment, the divot portion 1031 extends to at least a portion of the central portion 1010. In another alternative embodiment, the divot portion extends to at least a portion of the turning wheel portion 1008. The particular embodiment used depending on a given application for the semi-differential swerve drive may depend on to what extent the region in which the semi-differential swerve drive is height restricted and therefore to what extent the locomotion wheel needs to embed within the overall construction.

[0055] The axle 1026 further includes a driven bevel gear 1024. The driven bevel gear 1024 is rotationally fixed to one end of the axle, the driven bevel gear 1024 configured to have a meshing engagement with the plurality of bevel gear teeth 1021 of the drive wheel 1016.

[0072]

[0056] In an alternative embodiment, the axle 1026 further comprises an idle bevel gear 1030. The idle bevel gear 1030 is freely rotatable to the other end of the axle and is configured to stabilize and support the rotation of the axle around axis A and the roll of the axle around its rotational axis.

[0073]

[0057] In an alternative embodiment, a friction reduction arrangement (not shown) is interposed between the first surface 1005 of the seating portion 1004 and an upper surface of the turning wheel portion 1008. A friction reduction arrangement is likewise located in between the outer circumferential surface of the central portion 1010 and an inner circumferential surface of the second hollow cylindrical region 1003 of the force translation plate 1001. The friction reduction arrangement is preferably in the form of one or more bearings.

[0074]

[0058] In an alternative embodiment, a friction reduction arrangement (not shown) is interposed between the second surface 1006 of the seating portion 1004 and a bottom base of the drive wheel hollow cylindrical region 1017. A friction reduction arrangement is likewise located between the outer circumferential surface of the axle mounting portion 1009 and an inner circumferential surface of the central through hole of the annular region 1018. The friction reduction arrangement is preferably in the form of one or more bearings.

[0075]

[0059] In an alternative embodiment, a friction reduction arrangement (not shown) is interposed between the axle 1026 and the axle mounting portion 1009 on each side of the locomotion wheel 1022. In another alternative embodiment, the axle 1026 is constrained within the axle mounting apertures 1023 by the friction reduction arrangement located within the axle mounting apertures 1023. The friction reduction arrangement is preferably in the form of one or more bearings.

[0076]

[0060] In an alternative embodiment, circlips (not shown) are located within the axle mounting apertures 1023 to axially constrain the axle 1026 within the axle mounting aperture 1023. Circlips (not shown) are likewise used to axially constrain the locomotion wheel 1022, the drive bevel gear 1024 and the idle bevel gear 1030 to the axle 1026.

[0077]

[0061] When an external source (not shown) applies a current to the turn inrunner stator 1013, the turn inrunner stator 1013 causes the turn inrunner rotor 1011 to rotate around the axis A in either a clockwise or counterclockwise direction. Since the turn inrunner rotor 101 1 is in fixed engagement with the turning wheel portion 1008, the core assembly 1007 rotates in the corresponding direction. As the axle mounting portion 1007 is part of the core assembly 1007, the axle 1026 mounted on the axle mounting portion 1007 rotates around the axis A in the corresponding direction. As a result, the locomotion wheel 1022 turns in a leftward or rightward direction depending on the rotation of the turn inrunner rotor 1011. Simultaneously, if the drive wheel 1016 is stationary, the rotation of the axle 1026 around axis A causes the driven bevel gear 1024 to engage with one or more of the plurality of bevel gear teeth 1021. This causes the drive bevel gear 1024 to rotate, which ultimately causes the axle to also roll on its rotational axis, thereby drive the locomotion wheel 1014 in a forward or rearward direction, depending to the rotation of the turn inrunner rotor 101 1.

[0078]

[0062] When an external source (not shown) applies a current to the drive outrunner stator 1019, the drive outrunner stator 1019 causes the drive outrunner rotor 1020 to rotate around the axis A. Since the drive outrunner rotor 1020 is in fixed engagement with the drive wheel 1016, the drive wheel 1016 likewise rotates in the same direction around the axis A. This causes one or more of the plurality of bevel gear teeth 1021 to engage and actuate the rotation of the driven bevel gear 1024, which causes the axle 1026 to roll on its rotational axis, and thereby drive the locomotion wheel 1022 in a forward or rearward direction depending on the rotational direction of the drive outrunner rotor 1020.

[0079]

[0063] When a current is both applied to turn inrunner stator 1013 and the drive outrunner stator 1019 such that the drive wheel 1016 and the turning wheel portion 1008 is rotated the same amount and the same direction around axis A, the plurality of drive wheel bevel gear teeth 1021 does not drive the driven bevel gear 1024 to rotate on its axis since the axle moves the same direction as the drive wheel. Thus, the locomotion is not driven in a forward or rearward direction, but the locomotion wheel is turned in a leftward or rightward direction based on the rotation of the turn inrunner rotor 101 1.

[0080]

[0064] Accordingly, a semi-differential swerve drive can be operated to provide driving or turning and simultaneous driving and turning as desired.

[0081]

[0065] A second embodiment of the present invention is shown as 2000 in Figs 5-6. The semidifferential swerve drive 2000 comprises a force translation member 1001 . The force translation member 1001 comprises a first hollow cylindrical region 1002 and a second hollow cylindrical region 1003 wherein the first hollow cylindrical region 1002 has a smaller diameter than the second hollow cylindrical region 1003. A seating portion 1004 is located on a first end of the first hollow cylindrical region, the seating portion 1004 radially extending from an outer radius of the first hollow cylindrical region 1002 towards an inner radius of the second hollow cylindrical region 1003. The second hollow cylindrical region 1003 is connected to the seating portion of the first hollow cylindrical region 1002 such that an axis of the second hollow cylindrical region 1003 is aligned with an axis of the first hollow cylindrical region 1002, the axis being defined as axis A as shown in Fig. 6, and the first hollow cylindrical region 1003 defines a through-hole through the seating portion 1004. The seating portion 1004 is generally planar and perpendicular to the axis A. The seating portion 1004 has a first surface 1005 and a second surface 1006, the first surface 1005 facing the first hollow cylindrical region and the second surface 1006 facing the second hollow cylindrical region 1003.

[0082]

[0066] The semi-differential swerve drive 2000 further comprises a core assembly 1007. In the embodiment as shown in Fig. 6, the core assembly 1007 comprises a turning wheel portion 1008, an axle mounting portion 1009, and a central portion 1010. The central portion 1010 is substantially cylindrical in shape and extends axially through the first hollow cylindrical region and the second hollow cylindrical region 1003 of the force translation member 1001 along the axis A (see Fig. 6). The turning wheel portion 1008 is substantially cylindrical and hollow having a greater diameter than the central portion 1010, wherein the turning wheel portion comprises at its lower end a lower base portion 2001 . A first end of the central portion 1010 is connected to the lower base 2001 such that the axis of the central portion 1010 is aligned with the axis of the turning wheel portion 1008 and the turning wheel portion is adjacent a lower end of the first hollow cylindrical region 1002 of the force translation plate 1001. The axle mounting portion 1009 is at a second end of the central portion 1010, wherein the second end of the central portion 1010 protrudes out of the second hollow cylindrical region 1003.

[0083]

[0067] The turning wheel portion 1008 further comprises a turn outrunner rotor 2002. The turn outrunner rotor 2002 is substantially cylindrical and hollow defining a central through-aperture through which at least a portion of the turning wheel portion 1008 fits, wherein the central through-aperture defines an inner circumferential surface 2012 of the turn outrunner rotor 2002. The turn outrunner rotor 2002 has a greater diameter than the first hollow cylindrical region 1002 and a smaller diameter than the turning wheel portion 1008. The turn outrunner rotor 2002 is located within the turning wheel portion 1008 and atop an upper surface of the lower base portion 2001 such that an outer circumferential surface of the turn outrunner rotor 2002 is in fixed engagement with an inner circumferential surface of the turning wheel portion 1008. In an alternative embodiment, a lower end of the turn outrunner rotor 2002 is also in fixed engagement with the upper surface of the lower base portion 2001 . The semi-differential swerve drive 2000 also comprises a turn outrunner stator 2003 that is adapted for driving the turn outrunner rotor 2002. The turn outrunner stator 2003 is substantially cylindrical and hollow defining a central through-aperture through which at least a portion of the first hollow cylindrical region 1002 of the force translation member 1001 fits. The turn outrunner stator 2003 is located within the turning wheel portion 1008 such that the turn outrunner stator 2003 is surrounded by the turn outrunner rotor 2002 and an inner circumferential surface of the turn outrunner stator 2003 is in fixed engagement with in an outer circumferential surface of the first hollow cylindrical region 1002. In an alternative embodiment, an upper end of the turn outrunner stator 2003 is also in fixed engagement with at least a portion of the first surface 1005 of the seating portion 1004.

[0084]

[0068] The semi-differential swerve drive further comprises a drive wheel 1016. Referring to Figs. 5 and 6, the drive wheel has a drive wheel hollow cylindrical region 1017 and an annular region 1018 wherein the annular region 1018 has a greater diameter than the drive wheel hollow cylindrical region 1017. The annular region 1018 defines a central through aperture, the central through aperture of the annular region 1018 having substantially equal radius to the drive wheel hollow cylindrical region 1017. The annular region 1018 is located and connected to an upper end of the drive wheel hollow cylindrical region 1017 such that the axis of annular region 1018 is aligned with the axis of the hollow cylindrical region 1017 and that the drive wheel hollow cylindrical region 1017 forms a through hole through the central through aperture of the annular region 1018. The drive wheel 1016 is rotatably mounted in between at least a top region of the axle mounting portion 1009 and the second surface 1006 of the seating portion 1004 such that the axis of the driving wheel 1016 is aligned along axis A, at least portion of the drive wheel hollow cylindrical region 1017 is confined within the second hollow cylindrical region 1003, and at least a portion of the axle mounting portion 1009 is surrounded by an at least a portion of an inner circumferential surface of the annular region 1018.

[0085]

[0069] The drive wheel also comprises a plurality of bevel gear teeth 1021. The plurality of bevel gear teeth 1021 are located along a portion of the upper base surface of the annular region 1018.

[0086]

[0070] The semi-differential swerve drive 2000 comprises a drive inrunner stator 2004. The drive inrunner stator 2004 is substantially cylindrical and hollow defining a central through aperture. The drive inrunner stator 2004 is located within the second hollow cylindrical region 1003 such that an outer circumferential surface of the drive inrunner stator 2004 is in fixed engagement with an inner circumferential surface of the second hollow cylindrical region 1003 of the force translation plate 1001. In an alternative embodiment, a lower base surface of the drive inrunner stator 2004 is in fixed engagement with the second surface 1006 of the seating portion 1004.

[0087]

[0071] The drive wheel 1016 further comprises a drive inrunner rotor 2005 that is adapted to be driven by the drive inrunner stator 2004. The drive inrunner rotor 2005 is substantially cylindrical and hollow in defining a central through aperture with an inner circumferential surface. The drive inrunner rotor 2005 is located within the second hollow cylindrical region 1003 and is surrounded by the drive inrunner stator 2004 such that the drive inrunner rotor 2005 surrounds the drive wheel hollow cylindrical region 1017, and the inner circumferential surface of the drive inrunner rotor 2005 is in fixed engagement with an outer circumferential surface of the drive wheel hollow cylindrical region 1017. In an alternative embodiment, an upper base surface of the drive inrunner rotor 2005 is in fixed engagement with a lower base surface of the annular region 1018.

[0088]

[0072] The semi-differential swerve drive 1000 comprises an axle 1026 and a locomotion wheel 1022 assembly. The axle 1026 is rotationally mounted within a pair of axle mounting apertures 1023 (top portion of the axle mounting portion is not shown) on the axle mounting portion 1009 such that the axle is substantially perpendicular with the axis A. The locomotion wheel 1022 comprises an axle aperture 1023 through which the axle 1026 is inserted such that the locomotion wheel is mounted and in fixed engagement with the axle 1026 and the locomotion wheel is symmetrically aligned along the axis A in use.

[0089]

[0073] Preferably, at least a portion of the locomotion wheel 1022 extends within the axle mounting portion 1009 into an internal volume of the drive wheel 1016. In an alternative embodiment, at least a portion of the locomotion wheel 1022 also extends into a portion of the second hollow cylindrical region 1003 of the force translation member 1001. In another alternative embodiment, at least a portion of the locomotion wheel extends into a portion of the first hollow cylindrical region 1002 of the force translation member 1001. In another alternative embodiment, at least a portion of the locomotion wheel extends into an internal volume of the turning wheel portion 1008. In a specific embodiment as shown in Fig. 6, the axle mounting portion 1009 comprises a divot portion 1031 . At least a portion of the locomotion wheel 1022 extends to near the divot portion 1031 so that the locomotion wheel 1022 is freely rotatable around the axis of the axle without being obstructed by the axle mounting portion 1009. In another embodiment, the divot portion 1031 extends to at least a portion of the central portion 1010. In another alternative embodiment, the divot portion extends to at least a portion of the turning wheel portion 1008. The particular embodiment used depending on a given application for the semi-differential swerve drive may depend on to what extent the region in which the semi-differential swerve drive is height restricted and therefore to what extent the locomotion wheel needs to embed within the overall construction.

[0090]

[0074] The axle 1026 further includes a driven bevel gear 1024. The driven bevel gear 1024 is rotationally fixed to one end of the axle, the driven bevel gear 1024 configured to have a meshing engagement with the plurality of bevel gear teeth 1021 of the drive wheel 1016.

[0091]

[0075] In an alternative embodiment, the axle 1026 further comprises an idle bevel gear 1030. The idle bevel gear 1030 is freely rotatable on the other end of the axle and is configured to stabilize and support the rotation of the axle around axis A and the roll of the axle around its rotational axis.

[0076] In an alternative embodiment, a friction reduction arrangement is located in between the outer circumferential surface of the central portion 1010 and an inner circumferential surface of the first hollow cylindrical region 1002 of the force translation plate 1001 . The friction reduction arrangement is preferably in the form of one or more bearings.

[0092]

[0077] In an alternative embodiment, a friction reduction arrangement (not shown) is interposed between the second surface 1006 of the seating portion 1004 and a lower base of the drive wheel hollow cylindrical region 1017. A friction reduction arrangement is likewise located between the outer circumferential surface of the axle mounting portion 1009 and an inner circumferential surface of the central through hole of the annular region 1018. The friction reduction arrangement is preferably in the form of one or more bearings.

[0093]

[0078] In an alternative embodiment, a friction reduction arrangement (not shown) is interposed between the axle 1026 and the axle mounting portion 1009 on each side of the locomotion wheel 1022. In another alternative embodiment, the axle 1026 is constrained within the axle mounting apertures 1023 by the friction reduction arrangement located within the axle mounting apertures 1023. The friction reduction arrangement is preferably in the form of one or more bearings.

[0094]

[0079] In an alternative embodiment, circlips (not shown) are located within the axle mounting apertures 1023 to axially constrained the axle within the axle mounting aperture 1023. Circlips (not shown) are likewise used to axially constrain the locomotion wheel 1022, the drive bevel gear 1024 and the idle bevel gear 1030 to the axle 1026.

[0095]

[0080] Accordingly, a semi-differential swerve drive can be operated to provide driving or turning and simultaneous driving and turning as desired.

[0096]

[0081] When an external source (not shown) applies a current to the turn outrunner stator 2003, the turn outrunner stator 2003 causes the turn outrunner rotor 2002 to rotate around the axis A in either a clockwise or counterclockwise direction. Since the turn outrunner rotor 2003 is in fixed engagement with the turning wheel portion 1008, the core assembly 1007 rotates in the corresponding direction. As the axle mounting portion 1007 is part of the core assembly 1007, the axle 1026 mounted on the axle mounting portion 1007 rotates around the axis A in the corresponding direction. As a result, the locomotion wheel 1022 turns in a leftward or rightward direction depending on the rotational direction of the turn outrunner rotor 2002. Simultaneously, if the drive wheel 1016 is stationary, the rotation of the axle 1026 around axis A causes the driven bevel gear 1024 to engage with one or more of the plurality of bevel gear teeth 1021. This causes the drive bevel gear 1024 to rotate, which ultimately causes the axle to also roll on its rotational axis, thereby driving the locomotion wheel 1014 in a forward or rearward direction, depending to the rotation of the turn outrunner rotor 2002.

[0082] When an external source (not shown) applies a current to the drive inrunner stator 2004, the drive inrunner stator 2004 causes the drive inrunner rotor 2005 to rotate around the axis A. Since the drive inrunner rotor 2005 is in fixed engagement with the drive wheel 1016, the drive wheel 1016 likewise rotates in the same direction around the axis A. This causes one or more of the plurality of bevel gear teeth 1021 to engage and actuate the rotation of the driven bevel gear 1024, which causes the axle 1026 to roll on its rotational axis, and thereby drive the locomotion wheel 1022 in a forward or rearward direction depending on the rotational direction of the drive inrunner rotor 2005.

[0097]

[0083] When a current is both applied to turn outrunner stator 2003 and the drive inrunner stator 2004 such that the drive wheel 1016 and the turning wheel portion 1008 is rotated the same amount and the same direction around axis A, the plurality of drive wheel bevel gear teeth 1021 does not drive the driven bevel gear 1024 to rotate on its axis since the axle moves the same direction and amount as the drive wheel does. Thus, the locomotion is not driven in a forward or rearward direction, but the locomotion wheel is rotated in a leftward or rightward direction based on the rotation of the turn outrunner rotor 2002.

[0098]

[0084] A third embodiment of the present invention is shown as 3000 in Figs. 7-10. The semidifferential swerve drive 3000 comprises a force translation member 1001 . The force translation member 1001 comprises an annular region 3002 that defines a force translation member aperture 3003. In an alternative embodiment, the force translation member 1001 further comprises at least one mounting portion 3004 adapted for attaching the semidifferential swerve drive to an adjoining apparatus. Each mounting portion 3004 extends radially outward from a portion of an outer circumferential surface of the annular region 3002. The annular region 3002 of the force translation member 1001 defines a central axis A as shown in Fig. 10. The force translation member 1001 is generally planar and perpendicular to the axis A. The force translation member 1001 comprises a first surface 1005 and a second surface 1006.

[0099]

[0085] The semi-differential swerve drive 3000 further comprises a core assembly 1007. In the embodiment as shown in Figs. 8-10, the core assembly 1007 comprises an axle mounting portion 1009 and a core 1010. The core 1010 is substantially cylindrical in shape and comprises a first end and a second end. The core 1010 extends axially through the force translation member aperture 3003 along the axis A (see Fig. 10) such that the second end is on the side of the second surface 1006 of the force translation member 1001 and at least a portion of the first end of the core 1010 is surrounded by the inner circumferential surface of the annular region 3002. The axle mounting portion 1009 is at the second end of the core 1010.

[0086] The semi differential swerve drive further comprises a turning wheel portion 3005 is substantially cylindrical in shape having a greater diameter than the core assembly 1007. The turning wheel portion 3005 comprises an upper base portion 3006 and a lower base portion

[0100] 3007. A first end of the core 1010 is connected to the upper base portion 3006 of the turning wheel portion 3005 such that the axis of the core is aligned with the axis of the turning wheel portion 3005 and the upper base portion 3006 is substantially adjacent at least a portion of the first surface 1005 of the force translation member 1001.

[0101]

[0087] The turning wheel portion 3005 further comprises a plurality of turn worm contact teeth

[0102] 3008, the plurality of turn worm contact teeth 3008 being located along the outer circumferential surface of the turning wheel portion 3005. The semi-differential swerve drive 3000 further comprises a turn worm 3009 adapted to be driven by a motor (not shown), wherein the turn worm 3009 is in meshing engagement with the plurality of turn worm contact teeth.

[0103]

[0088] In an alternative embodiment, a plurality of turn spur gear teeth (not shown) can take the place of the plurality of turn worm contact teeth 3008. In this case, the turn worm 3009 is replaced by a turn spur gear (not shown), wherein the turn spur gear is in meshing engagement with the plurality of turn spur gear teeth and is adapted to be driven by a motor.

[0104]

[0089] The semi-differential swerve drive further comprises a drive wheel 1016. Referring to Figs. 8-10, the drive wheel 1016 is substantially cylindrical and hollow and comprises an upper base portion 3010 and a lower base portion 3011. The drive wheel 1016 is rotatably mounted substantially adjacent the second surface 1006 of the force translation member 1001 such that the rotational axis of the driving wheel 1016 is aligned with the axis A, an inner circumferential surface of the drive wheel 1016 surrounds at least a portion of the core 1010, and at least a portion of the axle mounting portion 1009 is surrounded by at least a portion of the inner circumferential surface of the drive wheel 1016.

[0105]

[0090] The drive wheel 1016 comprises a plurality of bevel gear teeth 1021 , the plurality of bevel gear teeth 1021 being located along the upper base portion 3010 of the drive wheel 1016. The drive wheel 1016 likewise comprises a plurality of drive worm wheel contact teeth 3012, the plurality of drive worm wheel contact teeth 3012 being located along an outer circumferential surface of the drive wheel 1016. The semi-differential swerve drive 3000 further comprises a drive worm 3013 adapted to be driven by a motor (not shown), wherein the drive worm is in meshing engagement with the plurality of drive worm wheel contact teeth 3012.

[0106]

[0091] In an alternative embodiment, a plurality of drive spur gear teeth (not shown) can take the place of the plurality of drive worm wheel contact teeth 3012. In this case, the drive worm 3013 is replaced by a drive spur gear (not shown), wherein the drive spur gear is in meshing engagement with the plurality of drive spur gear teeth and is adapted to be driven by a motor.

[0107]

[0092] An advantage of using the worm gear arrangement for the turning wheel portion and the drive wheel portion is that it is non-back-driveable. This feature can be useful when the semi-differential swerve drive is used for driving devices that should stay stationary when power is cut-off.

[0108]

[0093] The semi-differential swerve drive 3000 comprises an axle 1026 and a locomotion wheel 1022 assembly. The axle 1026 is rotationally mounted on a pair of axle mounting apertures 1023 on the axle mounting portion 1009 such that the axle is substantially perpendicular with the axis A. The locomotion wheel 1022 comprises an axle aperture 1023 through which the axle 1026 is inserted such that the locomotion wheel is mounted and is in fixed engagement with the axle 1026 and the locomotion wheel is symmetrically aligned along the axis A in use.

[0109]

[0094] Preferably, at least a portion of the locomotion wheel 1022 extends within the axle mounting portion 1009 into an internal volume of the drive wheel 1016. In an alternative embodiment, at least a portion of the locomotion wheel 1022 also extends into the force translation member aperture 3003. In another alternative embodiment, at least a portion of the locomotion wheel extends into an internal volume of the turning wheel portion 3005. In a specific embodiment as shown in Fig. 7 and 10, the axle mounting portion 1009 comprises a divot portion 1031. At least a portion of the locomotion wheel 1022 extends to near the divot portion 1031 so that the locomotion wheel 1022 is freely rotatable around the axis of the axle without being obstructed by the axle mounting portion 1009. In another embodiment, the divot portion 1031 extends to at least a portion of the core 1010. In another alternative embodiment, the divot portion extends to at least a portion of the turning wheel portion 3005. The particular embodiment used depending on a given application for the semi-differential swerve drive may depend on to what extent the region in which the semi-differential swerve drive is height restricted and therefore to what extent the locomotion wheel needs to embed within the overall construction.

[0110]

[0095] The axle 1026 further includes a driven bevel gear 1024. The driven bevel gear 1024 is rotationally fixed to one end of the axle, the driven bevel gear 1024 configured to have a meshing engagement with the plurality of bevel gear teeth 1021 of the drive wheel 1016.

[0111]

[0096] In an alternative embodiment, the axle 1026 further comprises an idle bevel gear 1030. The idle bevel gear 1030 is freely rotatable to the other end of the axle and is configured to stabilize and support the rotation of the axle around axis A and the roll of the axle around its rotational axis.

[0097] In an alternative embodiment, a friction reduction arrangement (not shown) is interposed between the first surface 1005 of the force translation member 1001 and an upper surface of the turning wheel portion 3005. A friction reduction arrangement is likewise located between the outer circumferential surface of the core 1010 and an inner circumferential surface of the annular region 3002 of the force translation member 1001 .

[0112]

[0098] In an alternative embodiment, A friction reduction arrangement is likewise located in between the second surface 1006 of the force translation member 1001 and a lower surface of the drive wheel 1016. The friction reduction arrangement is preferably in the form of one or more bearings. A friction reduction arrangement is likewise located between the outer circumferential surface of the axle mounting portion 1009 and an inner circumferential surface of the drive wheel 1016. The friction reduction arrangement is preferably in the form of one or more bearings.

[0113]

[0099] In an alternative embodiment, a friction reduction arrangement (not shown) is interposed between the axle 1026 and the axle mounting portion 1009 on each side of the locomotion wheel 1022. In another alternative embodiment, the axle 1026 is constrained within the axle mounting apertures 1023 by the friction reduction arrangement located within the axle mounting apertures 1023. The friction reduction arrangement is preferably in the form of one or more bearings.

[0114]

[0100] In an alternative embodiment, circlips (not shown) are located within the axle mounting apertures 1023 to axially constrained the axle within the axle mounting aperture 1023. Circlips (not shown) are likewise used to axially constrain the locomotion wheel 1022, the drive bevel gear 1024 and the idle bevel gear 1030 to the axle 1026.

[0115]

[0101] When an external source (not shown) powers a turn motor (not shown) operatively connected to the turn worm 3009, the turn worm 3009 rotates on its axis in either a clockwise or counterclockwise direction. Since the turn worm 3009 is in meshing engagement with the plurality of turn worm contact teeth 3008, the turn worm 3009 actuates the rotation of the turning wheel portion 3005 around the axis A. As the core 1010 is in fixed engagement with the turning wheel portion 1008, the core assembly 1007 rotates in the corresponding direction. As the axle mounting portion 1007 is part of the core assembly 1007, the axle 1026 mounted on the axle mounting portion 1007 rotates around the axis A in the corresponding direction. As a result, the locomotion wheel 1022 turns in a leftward or rightward direction depending on the rotational direction of the turn worm 3009. Simultaneously, if the drive wheel 1016 is stationary, the rotation of the axle 1026 around axis A causes the driven bevel gear 1024 to engage with one or more of the plurality of bevel gear teeth 1021 . This causes the drive bevel gear 1024 to rotate, which ultimately causes the axle to also roll on its rotational axis, thereby driving the locomotion wheel 1014 in a forward or rearward direction, depending to the rotation of the turn worm 3009.

[0116]

[0102] When an external source (not shown) powers a drive motor (not shown) operatively connected to the drive worm 3013, the drive worm 3013 rotates on its axis in either a clockwise or counterclockwise direction. Since the drive worm 3013 is in meshing engagement with the plurality of drive worm wheel contact teeth 3012, the drive worm 3013 actuates the rotation of the drive wheel 1016 around the axis A. This causes one or more of the plurality of bevel gear teeth 1021 to engage and actuate the rotation of the driven bevel gear 1024, which causes the axle 1026 to roll on its rotational axis, and thereby drive the locomotion wheel 1022 in a forward or rearward direction depending on the rotational direction of the drive inrunner rotor 2005.

[0117]

[0103] When both the turn worm 3009 and the drive worm 3013 are powered such that the drive wheel 1016 and the turning wheel portion 3005 is rotated the same amount and the same direction around axis A, the plurality of drive wheel bevel gear teeth 1021 does not drive the driven bevel gear 1024 to rotate on its axis since the axle moves the same direction and amount as the drive wheel does. Thus, the locomotion is not driven in a forward or rearward direction, but the locomotion wheel is rotated in a leftward or rightward direction based on the rotation of the turn worm 3009.

[0118]

[0104] Accordingly, a semi-differential swerve drive can be operated to provide driving or turning and simultaneous driving and turning as desired.

[0119] Interpretation

[0120] Markush Groups

[0121]

[0105] In addition, where features or aspects of the invention are described in terms of Markush groups, those skilled in the art will recognise that the invention is also thereby described in terms of any individual member or subgroup of members of the Markush group.

[0122] Chronological sequence

[0123]

[0106] For this specification, where method steps are described in sequence, the sequence does not necessarily mean that the steps are to be carried out in chronological order in that sequence, unless there is no other logical manner of interpreting the sequence.

[0124] Embodiments:

[0125]

[0107] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

[0126]

[0108] Similarly it should be appreciated that in the above description of example embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Description of Embodiments are hereby expressly incorporated into this Description of Embodiments, with each claim standing on its own as a separate embodiment of this invention.

[0127]

[0109] Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0128] Different Instances of Objects

[0129]

[0110] As used herein, unless otherwise specified the use of the ordinal adjectives “first”, “second”, “third”, etc., to describe a common object, merely indicate that different instances of like objects are being referred to and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.

[0130] Specific Details

[0131]

[0111] In the description provided herein, numerous specific details are set forth.lt is understood, however, that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0132] Terminology

[0133]

[0112] In describing the preferred embodiment of the invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. The invention is, however, not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar technical purpose. Terms such as "forward", "rearward", "radially", "peripherally", "upwardly", "downwardly", and the like are used as words of convenience to provide reference points and are not to be construed as limiting terms.

[0134]

[0113] As used herein the term “and / or” means “and” or “or”, or both.

[0135]

[0114] As used herein “(s)” following a noun means the plural and / or singular forms of the noun.

[0136] Comprising and Including

[0137]

[0115] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” are used in an inclusive sense, i.e., to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

[0138]

[0116] Any one of the terms: including or which includes or that includes as used herein is also an open term that also means including at least the elements / features that follow the term, but not excluding others. Thus, including is synonymous with and means comprising.

[0139] Scope of Invention

[0140]

[0117] Thus, while there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as fall within the scope of the invention. For example, any formulas given above are merely representative of procedures that may be used. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functional blocks. Steps may be added or deleted to methods described within the scope of the present invention.

[0141]

[0118] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

[0142] Industrial Applicability

[0143]

[0119] It is apparent from the above, that the arrangements described are applicable to the robotics, automotive, industrial and defence industries.

Claims

ClaimsThe claims defining the invention are as follows:1 . A semi-differential swerve drive for driving a moving apparatus, comprising:- a force translation member comprising a member aperture, the centre of the member aperture defining a first axis through the member aperture;- a core comprising:(i) a turning wheel portion, adapted to be driven around the first axis(ii) an axle mounting portion adapted to rotationally receive an axle wherein the core extends through the member aperture, such that the turning wheel portion is located to a first side of the force translation member and the axle mounting portion is located to a second side of the force translation member;- a drive wheel rotatably mounted between the second side of the force translation member and the axle mounting portion, the drive wheel surrounding the core in at least one plane and adapted to be driven about the first axis;- an axle rotationally mounted on the axle mounting portion;- a locomotion wheel mounted to the axle and in fixed engagement with the axle; and wherein the semi-differential swerve drive is adapted to translate torque from the drive wheel to the axle.

2. A semi-differential swerve drive as claimed in claim 1 , wherein the drive wheel is adapted to be driven about the first axis and comprises a driving bevel gear and the axle comprises at least one driven bevel gear rotationally fixed to the axle and in meshing engagement with the driving bevel gear.

3. A semi-differential swerve drive as claimed in claim 1 , wherein at least a portion of the locomotion wheel extends within the core into an internal volume of the drive wheel.4.A semi-differential swerve drive for driving a moving apparatus as claimed in Claim 3, wherein the at least a portion of the wheel that extends within the core into an internal volume of the drive wheel also extends into the member aperture.

5. A semi-differential swerve drive for driving a moving apparatus as claimed in Claim 4, wherein the at least a portion of the wheel that extends within the core into an internal volume of the drive wheel also extends into an internal volume of the turning wheel portion.

6. A semi-differential swerve drive as defined in claim 1 , further comprising a first stator and wherein the drive wheel comprises a first rotor.

7. A semi-differential swerve drive as defined in claim 6, wherein the first stator is in fixed engagement with the force translation member, and located to its second side, and surrounds the core, and the first rotor surrounds the first stator to provide a drive electric motor, such that when a current is applied to the first stator the first rotor rotates around the core, causing the axle to rotate.

8. A semi-differential swerve drive as defined in claim 7, wherein the drive wheel is adapted to be driven about the first axis and comprises a driving bevel gear and the axle comprises at least one driven bevel gear rotationally fixed to the axle and in meshing engagement with the driving bevel gear and the first rotor is in fixed engagement with the driving bevel gear.

9. A semi-differential swerve drive as defined in claim 1 , further comprising a second stator in fixed engagement with the force translation member and located to its first side, and wherein the turning wheel portion comprises a second rotor.

10. A semi-differential swerve drive as defined in claim 9, wherein the second stator surrounds the second rotor, and the second rotor surrounds and is in fixed engagement with the core to provide a turn electric motor, such that when a current is applied to the second stator the core rotates in relation to the force translation member.1 1 . A semi-differential swerve drive as defined in claim 6, wherein the force translation member comprises a second side facing hollow spigot through which the core extends and the first stator extends around an outer surface of the second side facing hollow spigot.

12. A semi-differential swerve drive as defined in claim 9, wherein the force translation member comprises a first side facing hollow spigot and the second stator extends around a portion of an inner surface of the first side facing hollow spigot.

13. A semi-differential swerve drive as defined in claim 1 , further comprising one or more friction reduction arrangements located at one or more locations from the following group of locations:(i) between the axle and the axle mounting portion on each side of the locomotion wheel;(ii) between a first side surface of the force translation member and an upper surface of the turning wheel portion;(iii) between a second side surface of the force translation member and a lower surface of the drive wheel;(iv) between the core and the force translation member; and(v) between the core and the drive wheel portion.

14. A semi-differential swerve drive as defined in claim 1 , wherein an outer circumferential surface of the turning wheel portion comprises a plurality of worm contact teeth adapted to be driven by a worm screw.

15. A semi-differential swerve drive as defined in claim 1 , wherein an outer circumferential surface of the drive wheel comprises a plurality of worm contact teeth adapted to be driven by a worm screw.

16. A semi-differential swerve drive as defined in claim 2, the axle further comprises at least one idle bevel gear rotationally mounted to the axle and in meshing engagement with the driving bevel gear.

17. A semi-differential swerve drive as defined in claim 1 , wherein the force translation member is adapted for attachment to the moving apparatus.

Images