DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Arguments
Applicant’s arguments, see page 11, filed 02/03/2026, with respect to the Drawing Objections and the 35 USC 112(b) rejection of claims 1-20 have been fully considered and are persuasive. The he Drawing Objections and the 35 USC 112(b) rejection of claims 1-20 have been withdrawn.
Applicant’s arguments with respect to independent claim(s) 1 and 12, and their depending claims have been fully considered. Regarding the limitation: “the power source being configured such that a direction of a torque on the rotor caused by the first stator and the second stator is a same direction” the Examiner acknowledges that Hirzel doesn’t explicitly recite this limitation. However, the limitation remains obvious in view of Hirzel and the knowledge of one of ordinary skill in the art. It is well understand in the art that an electric motor necessarily includes a power source for energizing stator windings in order to produce rotation. Further, multi-stator electric machines, it is a fundamental design consideration that stator windings are energized such that their respective electromagnetic torque contributions act in a common rotational direction, thereby producing usable net torque output. Configuring stators to produce opposing torque would reduce or cancel the net output torque and render the machine inefficient or inoperable for its intended purpose. Accordingly, one of ordinary skill in the art would have found it obvious to configure the power source energizing Hirzel’s first and second stators such that the torque produced by each stator acts in the same direction.
Hirzel explicitly teaches reducing torque ripple and achieving smooth torque output (see, e.g., para. 0127). Such an objective inherently requires that torque contributions from multiple stators be constructive rather than opposing, as opposing torque contributions would introduce instability and reduce net torque. Therefore, the claimed configuration is not only obvious but also consistent with and supportive of Hirzel’s stated design goals.
Applicant contends that Hirzel “teaches away” from the claimed invention by disclosing stator offset to reduce back EMF and torque ripple. This argument is not persuasive. A reference teaches away only when it discourages or criticizes the claimed solution. Hirzel does not disclose, suggest, nor imply that stators should be energized to produce torque in different rotational directions, nor do they suggest that such a configuration would be desirable. Instead Hirzel teaches adjusting phase relationships and spatial alignment between stators to influence waveform superposition, thereby reducing torque ripple and back EMF amplitude. These teachings relate to magnitude and smoothness of torque, not a reversal or opposition of torque direction. The reduction of back EMF to torque ripple through phase offset does not imply or require that the torque produced by the stators acts in opposite directions. Rather, such techniques are commonly employed while maintaining constructive torque production in a single rotational direction. Accordingly, Hirzel doesn’t teach away from the claimed invention.
Applicant asserts that configuring the power source such that torque is in the same direction would “maximize back EMF,” and that Hirzel teaches against such maximization. The argument is not persuasive because it is based on an incorrect premise. The direction of torque is determined by the direction of current and magnetic field interaction, whereas the magnitude of back EMF depends on factors such as flux linkage, rotational speed, and winding configuration. These are distinct physical phenomena. Hirzel’s teachings regarding reduction of back MEF amplitude through stator misalignment do not preclude or discourage energizing the stators such that their torque contributions act in the same direction.
For the reasons discussed above, the claimed limitation is an obvious design choice consistent with the intended operation of electric motors; Hirzel’s teachings are fully compatible with the claimed configuration; and Applicant has not provided persuasive evidence of teaching away or criticality. Accordingly, the rejection under 35 USC 103 is maintained.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1-6, 8-10, and 12-16 are rejected under 35 U.S.C. 103 as being unpatentable over Hirzel (US 20070024147 A1).
Claim 1
Hirzel teaches: An electric axial flux machine (Fig. 13) comprising:
a first stator (a selective first stator 42 or 44) having a first three-phase (N Phase windings of which may be defined by three phases, see para. 0089 and para. 0142) winding comprising a plurality of first stator poles (91, Fig. 33a) being mutually spaced in a circumferential direction of the electric axial flux machine (Fig. 13);
a second stator (a remaining unselected stator of the two stators 42 or 44) having a second three-phase (N Phase windings of which may be defined by three phases, see para. 0089 and para. 0142) winding comprising a plurality of second stator poles (91, Fig. 33A) being mutually spaced in the circumferential direction, the plurality of first stator poles (91, Fig. 33a) and the plurality of second stator poles (91, Fig. 33A) being interconnected to form a first phase (first of three phases, para. 0026) of the electric axial flux machine (Fig. 13), the plurality of second stator poles (91, Fig. 33A) forming the first phase being offset by an offset by an offset angle (S electrical degrees, wherein S=[360/(2NM)], para. 0026) in the circumferential direction in relation to the plurality of first stator poles forming the first phase;
a rotor (40) disposed between the first stator (a selective first stator 42 or 44) and the second stator (a remaining unselected stator of the two stators 42 or 44) and configured to rotate relative to the first stator (42) and the second stator (44), the rotor comprising a plurality of rotor poles (plural rotor pole pairs, para. 0026), a rotor pole distance is being defined by an angular distance between two adjacent rotor poles (the value in mechanical degrees equals the value in electrical degrees times the number of rotor pole pairs, para. 0026) of the plurality of rotor poles, the offset angle (S electrical degrees, wherein S=[360/(2NM)], para. 0026) being the rotor pole distance (1 full pole pitch, Fig. 9) or a multiple of the single rotor pole distance;
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Hirzel does not explicitly disclose “a power source for energizing the first stator and the second stator” as being present in their invention such that “the power source” is configured such that a direction of a torque on the rotor caused by the first stator and the second stator is a same direction is established.
Hirzel does however disclose their invention as comprising a machine generated EMF (back EMF) as a result of the misalignment (offset) of the two stators (para. 0119). Normally a back EMF from a device acts against a connected power source (according to Lenz’s Law) to reduce the overall voltage and current flowing through the device. Furthermore, in an effort to reduce torque ripple in their invention, Hirzel idealistically seeks to eliminate torque variations to produce a smooth output with substantially constant torque (para. 0127) embodied in the rotor.
In a motor, constant toque is directly proportional to its power output, meaning that as speed increases, the power required from the power source also increases linearly (Power = Torque x Speed). Additionally, the direction of torque is determined by the right-hand rule, which relates the direction of the torque vector to the directions of the current flow and the magnetic field created by the power source. Thus, under normal conditions, for the direction of torque on the rotor to be the same (i.e. constant), the power supply from the power source must be constant and the direction of current (which is based on the negative and positive terminal connection to the power source) must be constant. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have Hirzel’s axial flux machine comprise a power source for energizing the first and second stators such that the power source for energizing the first and second stators is designed such that the direction of the torque on the rotor caused by the first stator and second stator is the same. Having the direction of the torque on the rotor be the same (i.e. constant) provides consistent power for applications with steady loads, regardless of speed. This consistency ensures reliable performance and can improve process efficiency, and reduce mechanical stress.
Claim 2/1
Hirzel teaches: The electric axial flux machine (Fig. 13) according to claim 1, wherein the offset angle (S electrical degrees, wherein S=[360/(2NM)], para. 0026) is the rotor pole distance or an odd multiple of the rotor pole distance, wherein the power source is configured such that
the offset angle (S electrical degrees, wherein S=[360/(2NM)], para. 0026) corresponds to a single (1 full pole pitch, Fig. 9) or an odd multiple of the rotor pole distance;
Hirzel does not explicitly state that the current direction in on the second stator is reversed to the first stator so that the direction of the torque on the rotor cause by the first stator and the second stator is the same direction. Considering Hirzel’s teaching of an offset angle of one rotor pole pitch (which corresponds to 180 electrical degrees), the current direction is typically reversed in one of the stators relative to the other. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have ascertained Hirzel’s power source as being designed such the current direction in on the second stator is reversed to the first stator so that the direction of the torque on the rotor cause by the first stator and the second stator is the same direction. This configuration would cancel out undesirable harmonics (like even harmonics) and improve machine performance.
Claim 3/1
Hirzel teaches: The electric axial flux machine (Fig. 13) according to claim 1, but does not explicitly disclose: wherein the offset angle is twice the rotor pole distance or a multiple of twice the rotor pole distance.
Hirzel establishes that the offset between the two stators is expressed in terms of a pole pitch (para. 0117-0123). While Hirzel’s invention operates ideally in applications involving smaller pole pitches (i.e. smaller offset angle between the stators) up to a full pole pitch, higher pole pitch values may be implemented (para. 0122). An offset of two times the rotor pole pitch compared to one full pole pitch is possible yet not a meaningful modification in most cases as two times the rotor pole pitch is simply the same as two full pole pitch cycles, which would bring the offsetted stator back into a position that is magnetically equivalent to being fully aligned (or very close to it) with the reference stator. The optimal offset for purposes such as reducing cogging torque as intended by Hirzel, is typically half a pole pitch (or 180electrical degrees). This causes the cogging torques generated by each stator to be out of phase, allowing them to cancel each other out. Therefore, while would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have tested an offset angle that is twice the rotor pole distance or a multiple of twice the rotor pole distance, doing so would still function, effectively operating as a single, more powerful machine with both stators working in unison.
Claim 4/1
Hirzel teaches: The electric axial flux machine (Fig. 13) according to claim 1, but does not explicitly disclose: wherein the offset angle is three times the rotor pole distance or a multiple of three times the rotor pole distance.
Hirzel establishes that the offset between the two stators is expressed in terms of a pole pitch (para. 0117-0123). While Hirzel’s invention operates ideally in applications involving smaller pole pitches (i.e. smaller offset angle between the stators) up to a full pole pitch, higher pole pitch values may be implemented (para. 0122). An offset of three times the rotor pole pitch compared to one full pole pitch is possible yet not a meaningful modification in most cases as three times the rotor pole pitch is simply the same as three full pole pitch cycles, which would bring the offsetted stator back into a position that is magnetically equivalent to being fully aligned (or very close to it) with the reference stator. The optimal offset for purposes such as reducing cogging torque as intended by Hirzel, is typically half a pole pitch (or 180electrical degrees). This causes the cogging torques generated by each stator to be out of phase, allowing them to cancel each other out. Therefore, while would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have tested an offset angle that is thrice the rotor pole distance or a multiple of three the rotor pole distance, doing so would still function, effectively operating as a single, more powerful machine with both stators working in unison.
Claim 5/1
Hirzel teaches: The electric axial flux machine (Fig. 13) according to claim 1, but is silent to: wherein the offset angle is determined as an integer n times the rotor pole distance, with
n
=
k
g
V
(
N
P
h
;
M
)
·
P
h
2
N
wherein
kgV least common multiple;
N number of stator poles;
Ph number of phases;
and M number of rotor poles.
Although Hirzel does not explicitly express their offset angle as being defined by an integer n, expressed by the function above, Hirzel does explicitly disclose that the offset between the two stators is defined as a function of a pole pitch (para. 0121). This relationship can be understood based on Hirzel’s Figs. 3-9 which illustrate the results of the superposition of sinusoidal waveforms from two series connected stators at the position of the rotor for different degrees of offset between the two stators. The offset angle of the stators’ is therefore a result effective variable that is a function of the rotor pole pitch. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have reasonably determined an offset angle based on an integer n times the rotor pole distance, with n being defined by the expression above. Optimizing the offset angle between the two stators based on an integer multiple of the rotor pitch angle is a technique that would reduce cogging torque and suppress specific harmonic components.
Claim 6/1
Hirzel teaches: The electric axial flux machine (Fig. 13) according to claim 1, wherein the first three-phase winding (first set of windings, para. 0020) is a toothed coil winding (winding scheme entailing one coil per tooth 14, para. 0075) with the plurality of first stator poles (91, Fig. 33a) configured as coils and the second three-phase winding (second set of windings, para. 0020) is a toothed coil winding (winding scheme entailing one coil per tooth 14, para. 0075) with the plurality of second stator poles (91, Fig. 33A) configured as coils.
Claim 8/1
Hirzel teaches: The electric axial flux machine (Fig. 13) according to claim 1, wherein the rotor (40) has M rotor poles (plural rotor pole pairs, para. 0026).
Claim 9/8/1
Hirzel teaches: The electric axial flux machine (Fig. 13) according to claim 8, wherein the plurality of rotor poles (plural rotor pole pairs, para. 0026) are formed by permanent magnets (22) embedded in a main body of the rotor (40), wherein the permanent magnets (22) are magnetized in the circumferential direction of the electric axial flux machine (Fig. 13).
Claim 10/8/1
Hirzel teaches: The electric axial flux machine (Fig. 13) according to claim 8, wherein the plurality of rotor poles (plural rotor pole pairs, para. 0026) are formed by permanent magnets (22) in a shape of sectors of a circle or ring arranged at one end face of the rotor (40).
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Claim 12
An electric axial flux machine (Fig. 13) comprising:
a first stator (a selective first stator 42 or 44) having a first multi-phase winding comprising a plurality of first stator poles (91, Fig. 33a), the plurality of first stator poles (91, Fig. 33a) being spaced in the circumferential direction;
a second stator (a remaining unselected stator of the two stators 42 or 44) having a second multi-phase winding comprising a plurality of second stator poles (91, Fig. 33A), wherein the plurality of second stator poles (91, Fig. 33A) are spaced in a circumferential direction of the electric axial flux machine (Fig. 13);
some of the plurality of first stator poles (91, Fig. 33a) of the first multi-phase winding (first set of windings, para. 0020) and some of the plurality of second stator poles (91, Fig. 33A) of the second multi-phase winding (second set of windings, para. 0020) being interconnected to form a first phase (first of three phases, para. 0026) of the electric axial flux machine (Fig. 13);
the plurality of second stator poles (91, Fig. 33A) forming the first phase being offset by an offset by an offset angle (S electrical degrees, wherein S=[360/(2NM)], para. 0026) in the circumferential direction in relation to the plurality of first stator poles forming the first phase;
a rotor (40) disposed between the first stator (a selective first stator 42 or 44) and the second stator (a remaining unselected stator of the two stators 42 or 44), the rotor (40) being rotatable relative to the first stator (a selective first stator 42 or 44) and the second stator (a remaining unselected stator of the two stators 42 or 44), the rotor comprising a plurality of rotor poles (plural rotor pole pairs, para. 0026), a rotor pole distance is being defined by an angular distance between two adjacent rotor poles (the value in mechanical degrees equals the value in electrical degrees times the number of rotor pole pairs, para. 0026) of the plurality of rotor poles, the offset angle (S electrical degrees, wherein S=[360/(2NM)], para. 0026) being the rotor pole distance (1 full pole pitch, Fig. 9) or a multiple of the single rotor pole distance;
Hirzel does not explicitly disclose “a power source for energizing the first stator and the second stator” as being present in their invention such that “the power source” is configured such that a direction of a torque on the rotor caused by the first stator and the second stator is a same direction is established.
Hirzel does however disclose their invention as comprising a machine generated EMF (back EMF) as a result of the misalignment (offset) of the two stators (para. 0119). Normally a back EMF from a device acts against a connected power source (according to Lenz’s Law) to reduce the overall voltage and current flowing through the device. Furthermore, in an effort to reduce torque ripple in their invention, Hirzel idealistically seeks to eliminate torque variations to produce a smooth output with substantially constant torque (para. 0127) embodied in the rotor.
In a motor, constant toque is directly proportional to its power output, meaning that as speed increases, the power required from the power source also increases linearly (Power = Torque x Speed). Additionally, the direction of torque is determined by the right-hand rule, which relates the direction of the torque vector to the directions of the current flow and the magnetic field created by the power source. Thus, under normal conditions, for the direction of torque on the rotor to be the same (i.e. constant), the power supply from the power source must be constant and the direction of current (which is based on the negative and positive terminal connection to the power source) must be constant. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have Hirzel’s axial flux machine comprise a power source for energizing the first and second stators such that the power source for energizing the first and second stators is designed such that the direction of the torque on the rotor caused by the first stator and second stator is the same. Having the direction of the torque on the rotor be the same (i.e. constant) provides consistent power for applications with steady loads, regardless of speed. This consistency ensures reliable performance and can improve process efficiency, and reduce mechanical stress.
Claim 13/12
Hirzel teaches: The electric axial flux machine (Fig. 13) according to claim 12, wherein the offset angle is the rotor pole distance or an odd multiple of the rotor pole distance;
Hirzel does not explicitly state that the power source is configured such that the current direction in the second stator reversed to the first stator so that the direction of the torque on the rotor caused by the first stator and the second stator is the same direction. Considering Hirzel’s teaching of an offset angle of one rotor pole pitch (which corresponds to 180 electrical degrees), the current direction is typically reversed in one of the stators relative to the other. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have ascertained Hirzel’s power source as being designed such that in the event that the offset angle corresponds to a single or an odd multiple of the rotor pole distance, the current direction in one of the stators is reversed compared to an axial flux machine without offset so that the direction of the torque on the rotor caused by the first stator and second stator is the same. This configuration would cancel out undesirable harmonics (like even harmonics) and improve machine performance.
Claim 14/12
Hirzel teaches: The electric axial flux machine (Fig. 13) according to claim 12, but does not explicitly disclose: wherein the offset angle is twice the rotor pole distance or a multiple of twice the rotor pole distance.
Hirzel establishes that the offset between the two stators is expressed in terms of a pole pitch (para. 0117-0123). While Hirzel’s invention operates ideally in applications involving smaller pole pitches (i.e. smaller offset angle between the stators) up to a full pole pitch, higher pole pitch values may be implemented (para. 0122). An offset of two times the rotor pole pitch compared to one full pole pitch is possible yet not a meaningful modification in most cases as two times the rotor pole pitch is simply the same as two full pole pitch cycles, which would bring the offsetted stator back into a position that is magnetically equivalent to being fully aligned (or very close to it) with the reference stator. The optimal offset for purposes such as reducing cogging torque as intended by Hirzel, is typically half a pole pitch (or 180electrical degrees). This causes the cogging torques generated by each stator to be out of phase, allowing them to cancel each other out. Therefore, while would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have tested an offset angle that is twice the rotor pole distance or a multiple of twice the rotor pole distance, doing so would still function, effectively operating as a single, more powerful machine with both stators working in unison.
Claim 15/12
Hirzel teaches: The electric axial flux machine (Fig. 13) according to claim 12, but does not explicitly disclose: wherein the offset angle is three times the rotor pole distance or a multiple of three times the rotor pole distance.
Hirzel establishes that the offset between the two stators is expressed in terms of a pole pitch (para. 0117-0123). While Hirzel’s invention operates ideally in applications involving smaller pole pitches (i.e. smaller offset angle between the stators) up to a full pole pitch, higher pole pitch values may be implemented (para. 0122). An offset of three times the rotor pole pitch compared to one full pole pitch is possible yet not a meaningful modification in most cases as three times the rotor pole pitch is simply the same as three full pole pitch cycles, which would bring the offsetted stator back into a position that is magnetically equivalent to being fully aligned (or very close to it) with the reference stator. The optimal offset for purposes such as reducing cogging torque as intended by Hirzel, is typically half a pole pitch (or 180electrical degrees). This causes the cogging torques generated by each stator to be out of phase, allowing them to cancel each other out. Therefore, while would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have tested an offset angle that is thrice the rotor pole distance or a multiple of three the rotor pole distance, doing so would still function, effectively operating as a single, more powerful machine with both stators working in unison.
Claim 16/12
Hirzel teaches: The electric axial flux machine (Fig. 13) according to claim 12, wherein the first multi-phase winding (first set of windings, para. 0020) is a toothed coil winding (winding scheme entailing one coil per tooth 14, para. 0075) with the plurality of first stator poles (91, Fig. 33a) configured as coils and the second multi-phase winding (second set of windings, para. 0020) is a toothed coil winding (winding scheme entailing one coil per tooth 14, para. 0075) with the plurality of second stator poles (91, Fig. 33A) configured as coils.
Claims 7, 11, 17, and 19-20 are rejected under 35 U.S.C. 103 as being unpatentable over Hirzel in view of Mayer (DE 102019131198 A1).
Claim 7/1
Hirzel teaches: The electric axial flux machine (Fig. 13) according to claim 1, wherein each plurality of M polyphase stators each have N phase windings and a plurality of M full wave rectifier circuits for N-phase AC current (para. 0146). Hirzel is silent to their M circuits of each M polyphase stator as comprising of physical circuit boards and conductor tracks such that the limitation below can be realized:
the first stator comprises a first circuit board and the first three-phase winding has first conductor tracks which are arranged in the first circuit board, wherein the second stator comprises a second circuit board and the second three-phase winding has second conductor tracks which are arranged in the second circuit board.
Mayer conversely discloses an axial flux machine similar to that taught by Hirzel, comprising a plurality of stators (02), wherein the stators (02) comprise multilayer printed circuit boards (08) having openings each being surrounded by at least one of the electrical coils (07) in the form of the conductor tracks (Description, para. 46).
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It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have Hirzel’s M circuits of each M polyphase stator comprise of physical circuit boards and conductor tracks such that the limitation above can be realized. Employing PCBs for stators in an axial flux machine similar to that taught by Mayer offers advantages in being manufactured in a more compact and lightweight design which offers versatility in being used in robust applications such as in robot arms or transport vehicles (Description, para. 15).
Claim 11/1
Hirzel teaches the electric axial flux machine according to claim 1 as being equipped for applications involving drive wheels of a vehicle. Hirzel is silent to the implementation of their electric axial flux machine in an application involving an articulated arm of an industrial robot such that the following limitation can be realized:
A drive module for moving an articulated arm of an industrial robot having an electric axial flux machine according to claim 1.
Mayer conversely discloses an electric axial flux machine that has been optimized for use in many applications including transport vehicles similar to Hirzel as well as swiveling robot arms (Description, para. 52).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have optimized Hirzel’s electric axial flux machine to be used in a drive module for moving an articulated arm of an industrial robot. Employing an axial flux machine similar to that taught by Hirzel would be advantageous in applications involving articulated robot arms due to their high power density and high torque being packed in a compact manner, leading to more powerful and lighter arms.
Claim 17/12
Hirzel teaches: The electric axial flux machine (Fig. 13) according to claim 1, wherein each plurality of M polyphase stators each have N phase windings and a plurality of M full wave rectifier circuits for N-phase AC current (para. 0146). Hirzel is silent to their M circuits of each M polyphase stator as comprising of physical circuit boards and conductor tracks such that the limitation below can be realized:
the first stator comprises a first circuit board and the first multi-phase winding includes first conductor tracks arranged in the first circuit board and in that the second stator comprises a second circuit board and the second multi-phase winding includes second conductor tracks arranged in the second circuit board.
Mayer conversely discloses an axial flux machine similar to that taught by Hirzel, comprising a plurality of stators (02), wherein the stators (02) comprise multilayer printed circuit boards (08) having openings each being surrounded by at least one of the electrical coils (07) in the form of the conductor tracks (Description, para. 46).
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It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have Hirzel’s M circuits of each M polyphase stator comprise of physical circuit boards and conductor tracks such that the limitation above can be realized. Employing PCBs for stators in an axial flux machine similar to that taught by Mayer offers advantages in being manufactured in a more compact and lightweight design which offers versatility in being used in robust applications such as in robot arms or transport vehicles (Description, para. 15).
Claim 19
Hirzel teaches: An electric axial flux machine (Fig. 13) comprising: a first stator (a selective first stator 42 or 44) having a plurality of first stator poles (91, Fig. 33a), the plurality of first stator poles (91, Fig. 33a) being spaced in a circumferential direction of the electric axial flux machine (Fig. 13);
a second stator (a remaining unselected stator of the two stators 42 or 44) having a second multi-phase winding comprising a plurality of second stator poles (91, Fig. 33A), the plurality of second stator poles (91, Fig. 33A) being spaced in the circumferential direction
some of the plurality of first stator poles (91, Fig. 33a) of the first multi-phase winding (first set of windings, para. 0020) and some of the plurality of second stator poles (91, Fig. 33A) of the second multi-phase winding (second set of windings, para. 0020) being interconnected to form a first phase (first of three phases, para. 0026) of the electric axial flux machine (Fig. 13);
the plurality of second stator poles (91, Fig. 33A) forming the first phase being offset by an offset by an offset angle (S electrical degrees, wherein S=[360/(2NM)], para. 0026) in the circumferential direction in relation to the plurality of first stator poles forming the first phase;
a rotor (40) disposed between the first stator (a selective first stator 42 or 44) and the second stator (a remaining unselected stator of the two stators 42 or 44), the rotor (40) being rotatable relative to the first stator (a selective first stator 42 or 44) and the second stator (a remaining unselected stator of the two stators 42 or 44),
the rotor comprising a plurality of rotor poles (plural rotor pole pairs, para. 0026), a rotor pole distance is being defined by an angular distance between two adjacent rotor poles (the value in mechanical degrees equals the value in electrical degrees times the number of rotor pole pairs, para. 0026) of the plurality of rotor poles, the offset angle (S electrical degrees, wherein S=[360/(2NM)], para. 0026) being the rotor pole distance (1 full pole pitch, Fig. 9) or a multiple of the single rotor pole distance;
Hirzel does not explicitly disclose “a power source for energizing the first stator and the second stator” as being present in their invention such that “the power source” is configured such that a direction of a torque on the rotor caused by the first stator and the second stator is a same direction is established.
Hirzel does however disclose their invention as comprising a machine generated EMF (back EMF) as a result of the misalignment (offset) of the two stators (para. 0119). Normally a back EMF from a device acts against a connected power source (according to Lenz’s Law) to reduce the overall voltage and current flowing through the device. Furthermore, in an effort to reduce torque ripple in their invention, Hirzel idealistically seeks to eliminate torque variations to produce a smooth output with substantially constant torque (para. 0127) embodied in the rotor.
In a motor, constant toque is directly proportional to its power output, meaning that as speed increases, the power required from the power source also increases linearly (Power = Torque x Speed). Additionally, the direction of torque is determined by the right-hand rule, which relates the direction of the torque vector to the directions of the current flow and the magnetic field created by the power source. Thus, under normal conditions, for the direction of torque on the rotor to be the same (i.e. constant), the power supply from the power source must be constant and the direction of current (which is based on the negative and positive terminal connection to the power source) must be constant. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have Hirzel’s axial flux machine comprise a power source for energizing the first and second stators such that the power source for energizing the first and second stators is designed such that the direction of the torque on the rotor caused by the first stator and second stator is the same. Having the direction of the torque on the rotor be the same (i.e. constant) provides consistent power for applications with steady loads, regardless of speed. This consistency ensures reliable performance and can improve process efficiency, and reduce mechanical stress.
Furthermore, Hirzel teaches the electric axial flux machine (Fig. 13) as being equipped for applications involving drive wheels of a vehicle. Hirzel is silent to the implementation of their electric axial flux machine in an application involving an articulated arm of an industrial robot such that the following limitation can be realized:
An industrial robot comprising: a plurality of articulating arms; and one or more drive modules, the one or more drive modules being configured to move one or more of the plurality of articulating arms of the industrial robot, at least some of the one or more drive modules comprising an electric axial flux machine (Fig. 13) detailed above.
Mayer conversely discloses an electric axial flux machine that has been optimized for use in many applications including transport vehicles similar to Hirzel as well as swiveling robot arms (Description, para. 52).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have optimized Hirzel’s electric axial flux machine to be used in a An industrial robot comprising: a plurality of articulating arms; one or more drive modules, wherein the one or more drive modules are configured to move one or more of the articulated arms of the industrial robot, wherein at least some of the drive modules comprises the electric axial flux machine (Fig. 13) detailed above. Employing an axial flux machine similar to that taught by Hirzel would be advantageous in applications involving articulated robot arms due to their high power density and high torque being packed in a compact manner, leading to more powerful and lighter arms.
Claim 20/19
Hirzel as modified by Mayer teaches: The industrial robot according to claim 19, further comprising: a motor (Fig. 13); Hirzel does not however explicitly disclose their electric axial flux machine as comprising a rolling bearing arrangement however Hirzel does disclose their electric axial flux machine as comprising shaft supported bearings of any suitable type known for rotating machines. It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have optimized Hirzel’s electric axial flux machine to employ a rolling bearing arrangement specifically. Using a rolling bearing arrangement offers high load capacity and reduced friction, enabling it to handle heavy axial loads and high rotational speeds.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/AHMED F SECK/ Examiner, Art Unit 2834
/CHRISTOPHER M KOEHLER/Supervisory Patent Examiner, Art Unit 2834
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