Rotational drive type 2-speed transmission

Abstract

The electric motor includes a stator; a rotor having a rotor shaft; and a transmission coupled to the rotor shaft, such that when the rotor shaft rotates in a first direction, an output shaft of the transmission rotates in a second direction opposite to the first direction at a first gear ratio, and when the rotor shaft rotates in the second direction, the output shaft of the transmission rotates in the second direction at a second gear ratio different from the first gear ratio.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit under 35 U.S.C. § 119 of U.S. Provisional Patent Application No. 63 / 373,571, entitled "ROTATION DIRECTION DRIVEN TWO-SPEED TRANSMISSION," filed August 26, 2022, the disclosure of which is incorporated herein by reference in its entirety.

[0002] This document relates to a rotationally driven two-speed transmission. [Background technology]

[0003] In some current electric vehicles, electric motors are designed to operate without a gearbox. As a result, these motors always operate at a fixed gear ratio, thereby limiting their performance and efficiency. Other current electric vehicles use gearboxes that are capable of shifting between two gears. However, these gearboxes are complex mechanisms that are costly to manufacture; they have inefficiencies such as excessive resistance; and they impose significant inertial loads on the drivetrain (e.g., excessive jerk when shifting). Summary of the Invention

[0004] In a first aspect, the transmission includes a first sun gear; a first planetary gear having an axis fixed to a first gland within the transmission, the first planetary gear being a gear coupled to the first sun gear; a first ring gear being a gear coupled to the first planetary gear; a first carrier member holding the first ring gear; a second sun gear; a first one-way clutch coupled between the first carrier member and the second sun gear; a second one-way clutch coupled between the first sun gear and the second sun gear, the second one-way clutch having an opposite orientation to the first one-way clutch; a second planetary gear being a gear coupled to the second sun gear; a second ring gear being a gear coupled to the second planetary gear; a third one-way clutch coupled between the second ring gear and a second gland within the transmission, the third one-way clutch having a common orientation with the first one-way clutch; and a second carrier member holding the second ring gear.

[0005] Implementations may include any or all of the following features: the transmission further comprises an output shaft on the second carrier member; the first sun gear is aligned with the first planetary gear; the second sun gear is aligned with the first planetary gear; and the first carrier member and the second carrier member are aligned with each other.

[0006] In a second aspect, an electric motor includes a stator; a rotor having a rotor shaft; and a first sun gear; a first planetary gear including a shaft fixed to a first gland within the electric motor, the first planetary gear being a gear coupled to the first sun gear; a first ring gear being a gear coupled to the first planetary gear; a first carrier member holding the first ring gear; a second sun gear; a first one-way clutch coupled between the first carrier member and the second sun gear; and a second one-way clutch coupled between the first sun gear and the second sun gear. a second one-way clutch, the second one-way clutch having an opposite orientation to the first one-way clutch; a second planetary gear that is a gear coupled to the second sun gear; a second ring gear that is a gear coupled to the second planetary gear; a third one-way clutch coupled between the second ring gear and a second gland in the electric motor, the third one-way clutch having a common orientation with the first one-way clutch; and a transmission having a second carrier member that holds the second ring gear.

[0007] Implementations may include any or all of the following features: the electric motor further comprises an output shaft on the second carrier member; the first sun gear is aligned with the rotor shaft; the second sun gear is aligned with the rotor shaft; and the first carrier member and the second carrier member are aligned with each other.

[0008] In a third aspect, a vehicle includes a first electric motor providing passive reverse, the first electric motor having a first rotationally driven two-speed transmission; and a second electric motor.

[0009] Implementations may include any or all of the following features: the second electric motor is a single-speed electric motor; the vehicle further includes a transmission for the second electric motor; the first electric motor further includes a second rotationally driven two-speed transmission; the first electric motor is a rear motor on the vehicle and the second electric motor is a front motor on the vehicle; the second electric motor is a rear motor on the vehicle and the first electric motor is a front motor on the vehicle.

[0010] In a fourth aspect, the transmission includes a first sun gear; a first carrier member; first planetary gears having shafts fixed to the first carrier member; a first ring gear that is a gear coupled to the first planetary gears; a second carrier member that holds the first ring gear; a second sun gear coupled to the second carrier member; a first one-way clutch coupled between the first sun gear and the second sun gear; an intermediate gear that is coaxial with the first sun gear; a coupler that is movable between at least i) a first position, in which the coupler connects the first carrier member and the intermediate gear to one another, and ii) a second position, in which the coupler alternatively connects two components of the transmission to one another to facilitate operation in reverse gear and regenerative braking; and a second one-way clutch coupled between the intermediate gear and a ground within the transmission.

[0011] Implementations may include any or all of the following features: The transmission further comprises a solenoid configured to actuate the coupler to the first position or the second position. The first position corresponds to the transmission operating in either first gear or second gear. In the first gear, the second one-way clutch is engaged, preventing rotation of the intermediate gear. In the second gear, the second one-way clutch is not engaged. While the transmission is operating in the reverse gear with the coupler in the second position, at least the first sun gear, the first carrier member, the first planetary gears, the first ring gear, and the intermediate gear rotate as a unit. While the transmission is operating in the reverse gear during the regenerative braking, at least the first sun gear, the first carrier member, the first planetary gears, the first ring gear, and the intermediate gear rotate as a unit. The components are the first sun gear and the first planetary gear. The components are the first sun gear and the first ring gear, the components are the first planetary gears and the first ring gear.

[0012] In a fifth aspect, an electric motor comprises a stator; a rotor having a rotor shaft; and a transmission coupled to the rotor shaft, wherein when the rotor shaft rotates in a first direction, an output shaft of the transmission rotates in a second direction opposite to the first direction at a first gear ratio, and when the rotor shaft rotates in the second direction, the output shaft of the transmission rotates in the second direction at a second gear ratio different from the first gear ratio.

[0013] Implementations may include any or all of the following features: the transmission further includes a first sun gear coupled to the rotor shaft; first planetary gears including shafts fixed to a first gland in the transmission, the first planetary gears being gears coupled to the first sun gear; a first ring gear being gears coupled to the first planetary gears, the ring gear including a first carrier member; a second sun gear; second planetary gears being gears coupled to the second sun gear; a second ring gear being gears coupled to the second planetary gears; and a second carrier member that carries the second ring gear. The transmission further includes a first one-way clutch and a second one-way clutch, the first one-way clutch coupled between the first carrier member and the second sun gear, the second one-way clutch coupled between the first sun gear and the second sun gear, and the second one-way clutch having an opposite orientation to the first one-way clutch. The first one-way clutch engages with the output shaft, and the second one-way clutch engages with the output shaft. The electric motor includes a first transmission and a second transmission, wherein when the rotor shaft rotates in a first direction, the output shafts of the first transmission and the second transmission each rotate in the second direction opposite to the first direction at the first gear ratio, and when the rotor shaft rotates in the second direction, the output shafts of the first transmission and the second transmission each rotate in the second direction at the second gear ratio different from the first gear ratio.

[0014] In a sixth aspect, a transmission includes a first one-way clutch and a second one-way clutch, the second one-way clutch having an opposite orientation to the first one-way clutch, and the transmission changes gear ratio based on a change in the direction of rotation of an input shaft to the transmission without changing the direction of rotation.

[0015] An implementation may include any or all of the following features: the transmission further comprises a sun gear; a planetary gear coupled to the sun gear; and a cage coupled to the planetary gear. The first one-way clutch is coupled to an outer diameter of the input shaft and engages with the sun gear, and the second one-way clutch is coupled to an inner diameter of the input shaft and engages with an output shaft. The first one-way clutch is coupled to an inner diameter of the sun gear. The planetary gear has a fixed carrier. The input shaft is coupled to a rotor shaft. The cage is coupled to the output shaft. The second one-way clutch engages with the output shaft. The second one-way clutch engages with the output shaft via the cage. [Brief explanation of the drawings]

[0016] [Figure 1A] FIG. 1 illustrates an example of an electric motor with a rotationally driven two-speed transmission. [Figure 1B] FIG. 1 illustrates an example of an electric motor with a rotationally driven two-speed transmission. [Figure 1C] FIG. 1 illustrates an example of an electric motor with a rotationally driven two-speed transmission. [Figure 1D] FIG. 1 illustrates an example of an electric motor with a rotationally driven two-speed transmission.

[0017] [Figure 2A] FIG. 1 is a diagram illustrating an example of a rotationally driven two-speed transmission. [Figure 2B] FIG. 1 is a diagram illustrating an example of a rotationally driven two-speed transmission.

[0018] [Figure 3] 1 is a schematic cross-sectional view of an example of a rotationally driven two-speed transmission.

[0019] [Figure 4] 1 is a schematic diagram of an example vehicle having at least an electric motor and an electric motor with a rotationally driven two-speed transmission that provides passive reverse;

[0020] [Figure 5] FIG. 5 is a diagram illustrating an example of the rotationally driven two-speed transmission of FIG. 4.

[0021] [Figure 6A] FIG. 1 illustrates an example of a two-speed electric gearbox with regenerative braking and reverse capability, where the second speed function is directional drive. [Figure 6B] FIG. 1 illustrates an example of a two-speed electric gearbox with regenerative braking and reverse capability, where the second speed function is directional drive. [Figure 6C] FIG. 1 illustrates an example of a two-speed electric gearbox with regenerative braking and reverse capability, where the second speed function is directional drive. [Figure 6D] FIG. 1 illustrates an example of a two-speed electric gearbox with regenerative braking and reverse capability, where the second speed function is directional drive.

[0022] [Figure 7] 1 is a diagram illustrating an example of a powertrain in which a transmission is positioned between an electric motor and a wheel axle;

[0023] [Figure 8A] 1 is a diagram illustrating an example of a transmission location within a powertrain; [Figure 8B] 1 is a diagram illustrating an example of a transmission location within a powertrain; [Figure 8C] 1 is a diagram illustrating an example of a transmission location within a powertrain;

[0024] Like reference numbers in the various drawings indicate like elements. DETAILED DESCRIPTION OF THE INVENTION

[0025] This document describes example systems and techniques for providing a rotationally driven two-speed transmission. In some implementations, this may allow an electric motor to change gears by changing the direction in which its rotor is rotating. This may provide advantages over previous transmission approaches, such as reduced cost, more compact size, improved efficiency, and / or reduced inertial loads. The transmission may feature rotor-level decoupling to allow the vehicle to freewheel. For example, one of multiple electric motors in a vehicle may be decoupled when the vehicle is cruising to improve fuel economy.

[0026] Examples herein refer to vehicles. A vehicle is a machine that transports passengers, cargo, or both. A vehicle may have one or more electric motors. Examples of vehicles include, but are not limited to, cars, trucks, buses, motorcycles, and scooters. The number of wheels may vary depending on the type of vehicle, and one or more (e.g., all) of the wheels may be used to propel the vehicle. A vehicle may include a passenger compartment that accommodates one or more people. To name just a few examples, a vehicle may be powered solely by electricity or may use one or more other energy sources in addition to electricity.

[0027] The examples described herein refer to electric motors, which as used herein may be any type of electric motor, including but not limited to permanent magnet motors, induction motors, synchronous motors, or reluctance motors.

[0028] 1A-1D show an example of an electric motor 100 having a rotationally driven, two-speed transmission 102. FIG. 1A shows a perspective view of the electric motor 100, and FIG. 1C shows a cross-sectional view of the electric motor 100 taken along line AA in FIG. 1B. Here, the transmission 102 is mounted to one end of a motor housing 104 and can change gears based on the direction of rotation of the electric motor 100. The electric motor 100 and / or transmission 102 may be used with one or more other examples described elsewhere herein. The electric motor 100 may have a single-sided transmission or an active core-style dual planetary transmission, to name just two examples.

[0029] The transmission 102 has an output shaft 106. For example, the output shaft 106 may be coupled to a wheel axle (e.g., welded to a drive shaft) to be driven by the electric motor 100, or any other load. The electric motor 100 has a stator 108 and a rotor 110 inside a motor housing 104. The rotor 110 is rotatably coupled to a rotor shaft 112. When the rotor shaft 112 rotates in a first direction, the output shaft 106 of the transmission 102 rotates in a second direction opposite the first rotation at a first gear ratio. When the rotor shaft 112 rotates in the second direction, the output shaft 106 of the transmission 102 rotates in the second direction at a second gear ratio different from the first gear ratio. Thus, the electric motor 100 can change gears by changing the direction in which its rotor 110 and rotor shaft 112 are rotating. For example, electric motor 100 changes its direction of rotation by changing the direction of rotation of its magnetic field generated by stator 108. The change in motor rotation (i.e., the shifting between gears in transmission 102) may be done automatically by a motor control algorithm or may be triggered by a driver providing input to the vehicle.

[0030] In some implementations, electric motor 100 includes a transmission 114 mounted on the opposite end of motor housing 104 from transmission 102. Transmission 114 may include an output shaft 116 and, like transmission 102, may change gears based on the direction of rotation of electric motor 100. For example, when rotor shaft 112 rotates in a first direction, output shafts 106 and 116 rotate in a second direction opposite the first rotation at a first gear ratio. When rotor shaft 112 rotates in the second direction, output shafts 106 and 116 rotate in the second direction at a second gear ratio different from the first gear ratio.

[0031] 2A-2B schematically illustrate an example of a rotationally driven two-speed transmission. Here, transmission 200 is generally represented using a rectangular shape and can change gears based on the direction of rotation of an electric motor (e.g., electric motor 100 of FIGS. 1A-1D). While FIGS. 2A-2B are schematic and not purely cross-sectional, the perspectives presented therein approximate a cross-sectional view taken along line BB in FIG. 1D in an implementation in which transmission 102 includes the components of transmission 200. Transmission 200 may be used with one or more other examples described elsewhere herein.

[0032] Transmission 200 includes a sun gear 202. In some implementations, sun gear 202 may be coupled to a rotor shaft (e.g., rotor shaft 112 in FIGS. 1A-1D ) of an electric motor with which transmission 200 is used. Transmission 200 includes one or more planetary gears 204, which are gears coupled to sun gear 202. As shown schematically, each of planetary gears 204 may rotate about a fixed axis (e.g., may have a fixed center). Transmission 200 includes a ring gear 206, which is a gear coupled to planetary gears 204.

[0033] The transmission 200 includes a sun gear 208 that is driven by the rotation of the sun gear 202. The transmission 200 includes one or more planetary gears 210 that are gears coupled to the sun gear 208. The transmission 200 includes a ring gear 212 that is gear coupled to the planetary gears 210. As shown schematically, the ring gear 212 is at least temporarily fixed (e.g., the ring gear 212 may be at least temporarily fixed to the same structure as the rotational axis of the planetary gears 204). A carrier member 214 is coupled to the planetary gears 210. The carrier member 214 may drive an output shaft 216 of the transmission 200. For example, the output shaft 216 may be coupled to a wheel axle or any other load that is to be driven by an electric motor with the transmission 200.

[0034] Transmission 200 includes a one-way clutch 218 coupled to a carrier member 220, which is further coupled to (e.g., holds) a ring gear 206. Transmission 200 includes a one-way clutch 222 coupled to sun gear 202 and engaging sun gear 208. One-way clutch 218 has an opposite orientation to one-way clutch 222. Any of several types of one-way clutches may be used, including, but not limited to, a sprag clutch.

[0035] 2A illustrates an example of a first operating mode of transmission 200. Sun gear 202 rotates in direction 224. When sun gear 202 is viewed from the rotor shaft, direction 224 is, for example, clockwise. As sun gear 202 rotates in direction 224, one-way clutch 218 is engaged (i.e., transmits torque) and one-way clutch 222 is disengaged (i.e., does not transmit torque). Arrow 226 schematically indicates that as sun gear 202 rotates in direction 224 in the first operating mode, torque is transmitted by planet gears 204 and ring gear 206 to one-way clutch 218, which in turn drives sun gear 208. As a result, output shaft 216 rotates in direction 228, which is opposite to direction 224. The rotation of output shaft 216 in the first operating mode has a first gear ratio relative to the rotation of sun gear 202.

[0036] FIG. 2B illustrates an example of a second operating mode of transmission 200. Sun gear 202 rotates in direction 230, which is opposite direction 224 (FIG. 2A). When sun gear 202 is viewed from the rotor shaft, direction 230 is, for example, counterclockwise. Rotation of sun gear 202 in direction 230 disengages one-way clutch 218 (i.e., does not transmit torque) and engages one-way clutch 222 (i.e., transmits torque). Arrow 232 schematically indicates that rotation of sun gear 202 in direction 230 in the second operating mode results in torque being transmitted by one-way clutch 222 to drive sun gear 208. As a result, output shaft 216 rotates in direction 228, which is the same as direction 230. The rotation of output shaft 216 in the second operating mode has a second gear ratio relative to the rotation of sun gear 202. The second gear ratio is different from the first gear ratio, i.e., in the second mode of operation in which the sun gear 202 rotates in the opposite direction compared to the first mode of operation, the output shaft 216 rotates in the same direction as in the first mode of operation, but with a different gear ratio.

[0037] FIG. 3 shows a schematic cross-section of an example rotationally driven two-speed transmission. Here, transmission 300 may provide different gear ratios with the same direction of output rotation depending on the direction of input rotation. In essence, transmission 300 may represent an example in which an input shaft is sprag-coupled to either an output shaft or a sun gear to provide a rotationally driven two-speed transmission. While FIG. 3 is a schematic and not a true cross-section, the perspective presented therein approximates the cross-sectional view taken along line BB in FIG. 1D in an implementation in which transmission 102 includes the components of transmission 300. Transmission 300 may be used with one or more other examples described elsewhere herein.

[0038] Transmission 300 has an input shaft 302. In some implementations, input shaft 302 may be coupled to a rotor shaft of an electric motor with which transmission 300 is used (e.g., rotor shaft 112 in FIGS. 1A-1D ). Transmission 300 has a one-way clutch 304 (e.g., a sprag clutch) coupled to an outer diameter of input shaft 302. Transmission 300 has a one-way clutch 306 (e.g., a sprag clutch) coupled to an inner diameter of input shaft 302. One-way clutch 306 has an orientation opposite to the orientation of one-way clutch 304.

[0039] The one-way clutch 304 is engaged with a sun gear 308. The sun gear 308 is a gear coupled to a planetary gear 310 having a fixed carrier. The planetary gear 310 is a gear coupled to a cage 312, which is further coupled to an output shaft 314. When the input shaft 302 rotates in a first direction, the one-way clutch 304 is engaged (i.e., transmits torque) and the one-way clutch 306 is disengaged (i.e., does not transmit torque). Torque is then transmitted by the one-way clutch 304, the sun gear 308, the planetary gear 310, the cage 312, and the output shaft 314. As a result, the output shaft 314 rotates in a direction opposite to the direction in which the input shaft 302 is rotating. The rotation of the output shaft 314 has a first gear ratio relative to the rotation of the input shaft 302.

[0040] One-way clutch 306 engages output shaft 314 (e.g., via cage 312). When input shaft 302 rotates in a second direction opposite to the first direction, one-way clutch 304 disengages (i.e., does not transmit torque) and one-way clutch 306 engages (i.e., transmits torque). Torque is then transmitted by one-way clutch 306 and output shaft 314. As a result, output shaft 314 rotates in a direction that is the same as the second direction in which input shaft 302 is rotating. The rotation of output shaft 314 has a second gear ratio relative to the rotation of input shaft 302, the second ratio being different from the first ratio. Thus, transmission 300 shifts based on changes in the direction in which input shaft 302 is rotating.

[0041] Any of the transmissions illustrated herein may be used in any of several implementations, including, but not limited to, in vehicles. Vehicles such as electric motorcycles, scooters, and the like may have an electric motor coupled to a rotational direction drive two-speed transmission. For example, a motorbike may have one electric motor in implementations where reverse driving and regenerative braking are not required. Other vehicles, including, but not limited to, a car, bus, or truck, may have at least one electric motor with one or more transmissions according to the present subject matter, as in any of the above examples. In some implementations, such vehicles may have at least two electric motors: at least one electric motor with one or more transmissions according to the present subject matter, as in any of the above examples, and at least another electric motor with a different transmission whose operation is not controlled by rotational direction. For example, the vehicle may then use the other electric motor and its transmission to perform functions such as regenerative braking and / or driving the vehicle in reverse. An electric motor with a transmission according to the present subject matter, as in any of the above examples, may be installed anywhere within the vehicle, including, but not limited to, a rear drive unit.

[0042] Several examples of vehicles having multiple electric motors are now described. FIG. 4 schematically illustrates an example of a vehicle 400 having at least an electric motor 402 and an electric motor 404 with a rotationally driven two-speed transmission 406 providing passive reverse. FIG. 5 schematically illustrates an example of the rotationally driven two-speed transmission 406 of FIG. 4. The vehicle 400 is illustrated generally using a rectangle 408. For example, the rectangle 408 here represents the body, passenger cabin, chassis, wheels, energy storage (e.g., a battery pack), electrical system, and thermal system of the vehicle 400. At least one aspect of the examples of FIG. 4 and / or FIG. 5 may be used with one or more other examples described elsewhere herein.

[0043] Electric motor 402 may be configured to function with axle 410 of vehicle 400. Similarly, electric motor 404 may be configured to function with axle 412 of vehicle 400. Each of axles 410 and 412, shown here schematically as dashed lines, may be coupled to one or more respective road wheels (not shown) of vehicle 400. In some implementations, electric motor 402 may be referred to as the front motor of vehicle 400, and electric motor 404 may be referred to as the rear motor. In other implementations, electric motor 404 may be referred to as the front motor of vehicle 400, and electric motor 402 may be referred to as the rear motor.

[0044] Electric motor 402 may be a single speed electric motor or may have different gearing provided by one or more transmissions 414 or 416 mounted on the ends of a housing 418. Electric motor 402 has an output shaft 420 aligned with axle 410.

[0045] The electric motor 404 may have only a two-speed rotational drive transmission 406 mounted at one end of the housing 422, or may additionally have a two-speed rotational drive transmission 424 at the opposite end of the housing 422. The electric motor 404 has an output shaft 426 aligned with the axle 412.

[0046] To drive vehicle 400 forward, either or both electric motors 402 and 404 may operate in a forward direction. To drive vehicle 400 in reverse, electric motor 402 may operate in a reverse direction opposite to the forward direction. In this case, electric motor 404, which provides passive reverse, is not energized while electric motor 402 drives vehicle 400 in reverse.

[0047] Vehicle 400 may have more than two electric motors. For example, two electric motors may power axle 410 and one or more electric motors may power axle 412. As another example, two electric motors may power axle 412 and one or more electric motors may power axle 410.

[0048] Referring again to FIG. 5, rotationally driven two-speed transmission 406 includes several components that are the same as or similar to components of transmission 200 of FIG. 2A, and these components will not be described in detail here. As mentioned above, ring gear 212 of transmission 200 may be fixed (e.g., by splines). In contrast, rotationally driven two-speed transmission 406 includes a one-way clutch 500 (e.g., a sprag clutch) coupled between ring gear 212 and gland 502. One-way clutch 500 has the same orientation (i.e., a common orientation) as one-way clutch 218. The shaft of planetary gear 204 is shown as fixed to gland 508.

[0049] When electric motor 402 is driving vehicle 400 in reverse, the road wheels on axle 412 of electric motor 404 will rotate in the opposite direction. This will cause carrier member 214 of rotational drive two-speed transmission 406 to rotate in the opposite direction in direction 504. This rotation will engage one-way clutches 218 and 222. To avoid breaking a weak link in the transmission, ring gear 212 will rotate forward in direction 506. That is, in transmission 200 of FIG. 2A, if the electric motors were operating in reverse and competing with each other, one-way clutches 218 and 222 would both be engaged, causing a mechanical lock of the mechanism. In contrast, in rotational drive two-speed transmission 406, this situation is perfectly handled by one-way clutch 500 between ring gear 212 and gland 502. Arrow 510 indicates schematically that carrier member 220, ring gear 206, planet gears 204, and sun gear 202 are driven in power transmission from left to right in this illustration. The rotor shaft of electric motor 404 rotates in the opposite direction in direction 224 during passive reverse. That is, using rotationally driven two-speed transmission 406, electric motor 404 can provide two-speed operation while the vehicle is being driven forward and can provide passive reverse (without being energized) while the vehicle is being driven in reverse.

[0050] Figures 6A-6D show examples of two-speed electric gearboxes with regenerative braking and reverse capability, where the two-speed function is directional drive. Any or all aspects of the examples of Figures 6A-6D may be used in conjunction with one or more of the other examples described elsewhere herein.

[0051] The gearbox 600 includes several components that are the same as or similar to those of the transmission 200 of FIG. 2A, and these components will not be described in detail here. The transmission 200 has the shafts of the planetary gears 204 coupled to a gland; the gearbox 600, in turn, has a carrier member 602 coupled to the shafts of the planetary gears 204. The gearbox 600 has an intermediate gear 604 that is coaxial with the rotor shaft (not shown). A one-way clutch 606 (e.g., a sprag clutch) is coupled between the intermediate gear 604 and a gland 608. The gearbox 600 has a coupler 610 that is movable along the rotor shaft axis. A solenoid 612 is fixed inside the gearbox 600 (coupled to a gland, not shown) and can actuate the coupler 610 to move in either or both directions. In the situation shown in FIG. 6A, the coupler 610 has been moved toward the right in the figure and now connects the carrier member 602 and the intermediate gear 604 to each other.

[0052] Gearbox 600 may operate in first gear (e.g., as shown in FIG. 6A ), second gear (e.g., as shown in FIG. 6B ), reverse (e.g., as shown in FIG. 6C ), or regenerative braking mode (e.g., as shown in FIG. 6D ). Starting with FIG. 6A , coupler 610 currently connects carrier member 602 and intermediate gear 604 together, with the selection of first gear driven by the direction of rotor shaft rotation. That is, the current position of coupler 610 corresponds to gearbox 600 operating in first or second gear. The rotor shaft now rotates in the reverse direction, as indicated by direction 224. Arrow 614 schematically indicates that power is transmitted, here from right to left, through sun gear 202, planet gears 204, ring gear 206, and carrier member 220 to drive sun gear 208, which in turn rotates carrier member 214 in direction 228 (i.e., forward). First gear may have a relatively large gear ratio appropriate for this type of vehicle. For example, the speed of the road wheels driven by output shaft 216 may be a relatively low forward speed. In first gear, one-way clutch 606 is engaged, so that intermediate gear 604, coupler 610, and carrier member 602 are not currently rotating. One-way clutch 606 currently prevents rotation of at least intermediate gear 604.

[0053] To shift from first gear to second gear shown in FIG. 6B, the rotor shaft may instead be rotated forward (e.g., in direction 230). As in the first gear drive (FIG. 6A), the coupler 610 now connects the carrier member 602 and the intermediate gear 604 to one another. In some implementations, this position of the coupler 610 may be the default state for the solenoid 612. For example, when the solenoid 612 is inactive (de-energized), the absence of a generated magnetic field may cause the coupler 610 to assume the position shown in FIGS. 6A-6B (e.g., under the influence of a biasing member such as a spring). Due to the direction of rotation, the one-way clutch 606 is now disengaged. Thus, the interconnected intermediate gear 604 and coupler 610 will rotate as a unit in second gear. Arrow 616 indicates generally that power is transmitted, here from right to left through sun gear 202 and one-way clutch 218, to drive sun gear 208, which in turn rotates carrier member 214 in direction 228 (i.e., forward). The second gear may have a relatively small gear ratio appropriate for this type of vehicle. For example, the speed of the road wheels driven by output shaft 216 may be a relatively high forward speed.

[0054] To drive the vehicle in reverse, as shown in FIG. 6C , the solenoid 612 can be actuated to move the coupler 610 toward the left in this figure. This position of the coupler 610 facilitates operation in reverse gear. In some implementations, this is a non-default state for the solenoid 612 (e.g., when the solenoid 612 is energized, the coupler 610 moves against the bias to assume the position shown). The coupler 610 thus connects the carrier member 602 and the sun gear 202 to one another. Arrow 614 schematically indicates that power is transmitted, here from right to left, through the sun gear 202, planet gears 204, ring gear 206, and carrier member 220 to drive the sun gear 208, which in turn rotates the carrier member 214 in direction 504 (i.e., reverse). When driving in reverse, the one-way clutches 218 and 606 are disengaged. Thus, when driving in reverse, the first stage of gearbox 600 will rotate as a unit.

[0055] To obtain regenerative braking, as shown in FIG. 6D , solenoid 612 can be actuated to move coupler 610 toward the left in this figure. This position of coupler 610 facilitates regenerative braking. The rotor shaft can be rotated in a forward direction (e.g., in direction 230). For example, while the vehicle is traveling in second gear (e.g., as in FIG. 6B ), coupler 610 can be moved to connect carrier member 602 and sun gear 202 to each other. Arrow 510 indicates schematically that power is transmitted from left to right, here through carrier member 220, ring gear 206, planet gear 204, and sun gear 202, while carrier member 214 rotates in direction 228 (i.e., forward). One-way clutches 218 and 606 are disengaged during regenerative braking. Thus, during regenerative braking, the first stage of gearbox 600 rotates as a unit.

[0056] In some of the examples above, the coupler 610, in its left position, connects the sun gear 202 and the carrier member 602 (i.e., the planet gears 204) to each other. Other approaches may be used. In some implementations, the coupler 610 may be used to connect any two of the following: (a) the sun gear 202, (b) the planet gears 204, or (c) the ring gear 206 to each other. Thus, a two-speed electric gearbox with regenerative braking and reverse capability and directional drive two-speed function may be provided, where the coupler 610 provides either the connection (a)-(b), (a)-(c), or (b)-(c).

[0057] Some of the examples described above involve arrangements in which the transmission is aligned with the rotor shaft of the electric motor. For example, in Figures 1A-1D, the rotationally driven two-speed transmission 102 is aligned with the rotor shaft 112. However, any of several other positions for the transmission may be used, for example, as described below.

[0058] FIG. 7 schematically illustrates an example of a powertrain 700 in which a transmission 702 is positioned between an electric motor 704 and a wheel axle 706. The powertrain 700 is shown schematically, and some features are omitted for simplicity. One or more gear shapes may be used, including, but not limited to, frusto-conical or cylindrical. One or more types of gear teeth may be used, including, but not limited to, helical gears or straight-cut gears. The powertrain 700 or any component thereof may be used with one or more other examples described elsewhere herein. For example, the transmission 702 may include any of the transmissions described elsewhere herein.

[0059] Here, the rotational axis of transmission 702 is not aligned with (but is parallel to) the rotational axis of electric motor 704. Similarly, the rotational axis of transmission 702 is not aligned with (but is parallel to) the rotational axis of wheel axle 706. Notably, powertrain 700 has an idler gear assembly 708 positioned between electric motor 704 and wheel axle 706. Idle gear assembly 708 includes gear 710, which is a gear coupled to a gear on rotor shaft 712 of electric motor 704. Idle gear assembly 708 also includes gear 714, which is a gear coupled to gear 716 on wheel axle 706. Wheel axle 706 can extend in either or both directions from gear 716 and can drive one or more wheels of the vehicle. The respective rotational axes of gears 710 and 714 are coaxial with the rotational axis of transmission 702. Transmission 702 may provide passive reverse and / or rotational direction driven gear selection.

[0060] 8A-8C schematically illustrate examples of transmission locations within a powertrain. The powertrain is shown schematically and not in pure cross section; however, each of the presented perspectives approximately represents a cross-sectional view taken along line CC in FIG. 1D in an implementation in which electric motor 100 has a transmission positioned according to the respective example. Any of the locations shown may be used with one or more other examples described elsewhere herein. For example, any of the transmissions described herein may be used as the transmission referred to in any of the following examples.

[0061] 8A shows a powertrain 800 including an electric motor 802 having a rotor shaft 804 defining an axis 806. Powertrain 800 includes a gear 808 that is driven directly or indirectly by rotor shaft 804. Gear 808 is coupled to gear 810 that is part of an idler gear assembly 812. Idle gear assembly 812 also includes gear 814, and thus idler gear assembly 812 has an axis 816. Gear 814 is coupled to gear 818 of a wheel axle assembly 820. Wheel axle assembly 820 also includes a wheel axle 822 that is driven directly or indirectly by gear 818 according to axis 824. Axles 806, 816, and 824 are here parallel to one another.

[0062] In powertrain 800, transmission 826 is positioned on rotor shaft 804. In some implementations, transmission 826 may be coaxial with rotor shaft 804. For example, transmission 200 ( FIGS. 2A-2B ) and / or transmission 300 ( FIG. 3 ) may be used as transmission 826. Transmission 826 may provide a connection between rotor shaft 804 (e.g., having a relatively small outer diameter) and gear 808 (e.g., having a relatively large inner diameter) in a manner similar to how transmission 200 ( FIGS. 2A-2B ) provides a connection between sun gear 202 (e.g., having a relatively small outer diameter) and carrier member 214 (e.g., having a relatively large inner diameter).

[0063] 8B shows powertrain 830 having transmission 832 included in idler gear assembly 834. Idle gear assembly 834 also includes gears 810 and 814, with transmission 832 positioned between gears 810 and 814. In summary, powertrain 830 includes electric motor 802, rotor shaft 804, axle 806, gear 808, idler gear assembly 834 having gears 810 and 814 and axle 816, and wheel axle assembly 820 having gear 818 and wheel axle 822 and axle 824. That is, in powertrain 830, transmission 832 is positioned within idler gear assembly 834 rather than rotor shaft 804. For example, transmission 702 (FIG. 7) may be used as transmission 832. Transmission 832 can provide a connection between gear 810 (e.g., having a relatively large inner diameter) and gear 814 (e.g., having a relatively small inner diameter) in a manner similar to how transmission 200 (FIGS. 2A-2B) provides a connection between ring gear 206 (e.g., having a relatively large inner diameter) and carrier member 214 (e.g., having a relatively small inner diameter).

[0064] 8C shows a powertrain 840 having a transmission 842 included in a wheel axle assembly 844. The wheel axle assembly 844 also includes a gear 818 and a wheel axle 822 and axle 824, with the transmission 842 positioned between the gear 818 and the wheel axle 822. In summary, the powertrain 840 includes an electric motor 802, a rotor shaft 804, axle 806, a gear 808, an idler gear assembly 812 having gears 810 and 814 and axle 816, and a wheel axle assembly 844 having gear 818, a transmission 842, and axle 822 and axle 824. That is, in the powertrain 840, the transmission 842 is positioned within the wheel axle assembly 844, rather than within the idler gear assembly 812 or the rotor shaft 804. Transmission 842 can provide a connection between gear 818 (e.g., having a relatively large inner diameter) and axle 822 (e.g., having a relatively small outer diameter) in a manner similar to how transmission 200 (FIGS. 2A-2B) provides a connection between ring gear 206 (e.g., having a relatively large inner diameter) and carrier member 214 (e.g., having a relatively small outer diameter).

[0065] As used throughout this specification, the terms "substantially" and "about" are used to describe and report small variations, such as those due to processing variations. For example, they can refer to less than or equal to ±5%, such as less than or equal to ±2%, such as less than or equal to ±1%, such as less than or equal to ±0.5%, such as less than or equal to ±0.2%, such as less than or equal to ±0.1%, such as less than or equal to ±0.05%. Also, as used herein, indefinite articles such as "a" or "an" mean "at least one."

[0066] It should be understood that all combinations of the foregoing concepts, and additional concepts discussed in more detail below, (provided such concepts are not mutually inconsistent) are contemplated as being part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the inventive subject matter disclosed herein.

[0067] Although several implementations have been described, it will be understood that various modifications may be made without departing from the spirit and scope of the present specification.

[0068] Additionally, the logic flows depicted in the figures do not require the particular order shown, or sequential order, to achieve desirable results. Additionally, other processes may be provided in or deleted from the described flows, and other components may be added to or removed from the described systems. Accordingly, other implementations are within the scope of the following claims. While several features of the described implementations are shown as described herein, many modifications, substitutions, changes, and equivalents will now occur to those skilled in the art. Therefore, it should be understood that the appended claims are intended to cover all such modifications and variations that fall within the scope of the implementations. They have been presented by way of example only, and not limitation, and it should be understood that various changes in form and detail may be made. Any portions of the apparatus and / or methods described herein may be combined in any combination, except mutually exclusive combinations. The implementations described herein may include various combinations and / or subcombinations of the functions, components, and / or features of the various described implementations.

Claims

1. A transmission, First sun gear; a first planetary gear having an axis fixed to a first gland in the transmission, the first planetary gear being a gear coupled to the first sun gear; a first ring gear coupled to the first planetary gear; a first carrier member that holds the first ring gear; Second sun gear; a first one-way clutch coupled between the first carrier member and the second sun gear; a second one-way clutch coupled between the first sun gear and the second sun gear, the second one-way clutch having an opposite orientation to the first one-way clutch; a second planetary gear coupled to the second sun gear; a second ring gear coupled to the second planetary gear; a third one-way clutch coupled between the second ring gear and a second gland within the transmission, the third one-way clutch having a common orientation with the first one-way clutch; and a second carrier member that holds the second ring gear; A transmission comprising:

2. The transmission of claim 1 further comprising an output shaft on said second carrier member.

3. 3. The transmission of claim 1 or 2, wherein the first sun gear is aligned with the first planetary gear.

4. 3. The transmission of claim 1, wherein the second sun gear is aligned with the first planetary gear.

5. 3. The transmission of claim 1 or 2, wherein the first carrier member and the second carrier member are aligned with one another.

6. 1. An electric motor, comprising: stator; a rotor having a rotor shaft; and First sun gear; a first planetary gear including a shaft fixed to a first ground within the electric motor, the first planetary gear being a gear coupled to the first sun gear; a first ring gear coupled to the first planetary gear; a first carrier member that holds the first ring gear; Second sun gear; a first one-way clutch coupled between the first carrier member and the second sun gear; a second one-way clutch coupled between the first sun gear and the second sun gear, the second one-way clutch having an opposite orientation to the first one-way clutch; a second planetary gear coupled to the second sun gear; a second ring gear coupled to the second planetary gear; a third one-way clutch coupled between the second ring gear and a second gland within the electric motor, the third one-way clutch having a common orientation with the first one-way clutch; and a second carrier member that holds the second ring gear; A transmission having An electric motor comprising:

7. The electric motor of claim 6 further comprising an output shaft on the second carrier member.

8. 8. An electric motor according to claim 6 or 7, wherein the first sun gear is aligned with the rotor shaft.

9. 8. An electric motor according to claim 6 or 7, wherein the second sun gear is aligned with the rotor shaft.

10. 8. The electric motor of claim 6 or 7, wherein the first carrier member and the second carrier member are aligned with one another.

11. a first electric motor providing passive reverse, the first electric motor having a first rotationally driven two-speed transmission; and Second electric motor A vehicle equipped with:

12. 12. The vehicle of claim 11, wherein the second electric motor is a single speed electric motor.

13. The vehicle of claim 11 further comprising a transmission for the second electric motor.

14. 14. The vehicle of claim 11, wherein the first electric motor further comprises a second rotationally driven two-speed transmission.

15. 14. The vehicle according to claim 11, wherein the first electric motor is a rear motor of the vehicle, and the second electric motor is a front motor of the vehicle.

16. The vehicle according to any one of claims 11 to 13, wherein the second electric motor is a rear motor of the vehicle, and the first electric motor is a front motor of the vehicle.

17. A transmission, First sun gear; a first carrier member; a first planetary gear having an axis fixed to said first carrier member; a first ring gear coupled to the first planetary gear; a second carrier member that holds the first ring gear; a second sun gear coupled to the second carrier member; a first one-way clutch coupled between the first sun gear and the second sun gear; an intermediate gear coaxial with the first sun gear; a coupler movable between at least i) a first position in which the coupler connects the first carrier member and the intermediate gear to one another, and ii) a second position in which the coupler alternatively connects two components of the transmission to one another to facilitate operation in reverse gear and regenerative braking; and a second one-way clutch coupled between the intermediate gear and a gland within the transmission; A transmission comprising:

18. 18. The transmission of claim 17, further comprising a solenoid configured to actuate the coupler to the first position or the second position.

19. 20. The transmission of claim 18, wherein the first position corresponds to the transmission operating in either first gear or second gear.

20. 20. The transmission of claim 19, wherein in said first gear, said second one-way clutch is engaged to prevent rotation of said intermediate gear.

21. 20. The transmission of claim 19, wherein in said second gear, said second one-way clutch is disengaged.

22. 22. The transmission of any one of claims 17 to 21, wherein while the transmission is operating in reverse gear with the coupler in the second position, at least the first sun gear, the first carrier member, the first planetary gears, the first ring gear, and the intermediate gear rotate as a unit.

23. 22. The transmission of any one of claims 17 to 21, wherein while the transmission is operating in the reverse gear during the regenerative braking, at least the first sun gear, the first carrier member, the first planetary gears, the first ring gear, and the intermediate gear rotate as a unit.

24. A transmission according to any one of claims 17 to 21, wherein the components are the first sun gear and the first planetary gear.

25. A transmission according to any one of claims 17 to 21, wherein the components are the first sun gear and the first ring gear.

26. A transmission according to any one of claims 17 to 21, wherein the components are the first planetary gear and the first ring gear.

27. stator; a rotor having a rotor shaft; and a transmission coupled to the rotor shaft, wherein when the rotor shaft rotates in a first direction, an output shaft of the transmission rotates in a second direction opposite to the first direction at a first gear ratio, and when the rotor shaft rotates in the second direction, the output shaft of the transmission rotates in the second direction at a second gear ratio different from the first gear ratio; An electric motor comprising:

28. The transmission is a first sun gear coupled to the rotor shaft; a first planetary gear including a shaft fixed to a first gland in the transmission, the first planetary gear being a gear coupled to the first sun gear; a first ring gear coupled to the first planetary gear, the first ring gear including a first carrier member; Second sun gear; a second planetary gear coupled to the second sun gear; a second ring gear, the second ring gear being a gear coupled to the second planetary gear; and a second carrier member that holds the second ring gear; 28. The electric motor of claim 27, further comprising:

29. The transmission is a first one-way clutch and a second one-way clutch, the first one-way clutch being coupled between the first carrier member and the second sun gear, the second one-way clutch being coupled between the first sun gear and the second sun gear, the second one-way clutch having an opposite orientation to the first one-way clutch; 30. The electric motor of claim 28, further comprising:

30. 30. The electric motor of claim 29, wherein the first one-way clutch engages the output shaft and the second one-way clutch engages the output shaft.

31. 31. The electric motor of claim 28, further comprising a first transmission and a second transmission, wherein when the rotor shaft rotates in a first direction, the output shafts of the first transmission and the second transmission each rotate in the second direction opposite to the first direction at the first gear ratio, and when the rotor shaft rotates in the second direction, the output shafts of the first transmission and the second transmission each rotate in the second direction at the second gear ratio different from the first gear ratio.

32. A transmission, a first one-way clutch and a second one-way clutch, the second one-way clutch having an opposite orientation to the first one-way clutch, wherein the transmission changes gear ratio based on a change in rotational direction of an input shaft to the transmission without changing rotational direction; A transmission comprising:

33. The transmission is Sun gear; a planetary gear coupled to the sun gear; and A cage, which is a gear coupled to the planetary gear 33. The transmission of claim 32, further comprising:

34. 34. The transmission of claim 33, wherein the first one-way clutch is coupled to an outer diameter of the input shaft and engages the sun gear, and the second one-way clutch is coupled to an inner diameter of the input shaft and engages an output shaft.

35. 35. The transmission of claim 34, wherein the first one-way clutch is coupled to an inner diameter of the sun gear.

36. 36. A transmission according to claim 34 or 35, wherein the planetary gears have fixed carriers.

37. 36. A transmission according to claim 34 or 35, wherein the input shaft is coupled to a rotor shaft.

38. 38. The transmission of claim 37, wherein the cage is coupled to the output shaft.

39. 39. The transmission of claim 38, wherein the second one-way clutch engages the output shaft.

40. 40. The transmission of claim 39, wherein the second one-way clutch engages the output shaft through the cage.

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