Automated electric manual transmission

Abstract

Transmission (14), comprising: an input element (18); an output element (52); at least one transmission shaft (20); wherein the input element (18) and the at least one transmission shaft (20) are rotatable about a first axis of rotation (23); a countershaft (22) arranged substantially parallel to the at least one transmission shaft (20) and rotatable about a second rotational axis (25); wherein the output member (52) is operatively connected to rotate with the countershaft (22); a plurality of pairs of meshing gears (24, 30; 28, 34; 26, 32); each of the pairs of meshing gears (24, 30; 28, 34; 26, 32) being operable to provide a different gear ratio between the at least one transmission shaft (20) and the countershaft (22); a plurality of selectively engageable synchronizers (A, B); wherein at least some of the pairs of meshing gears (24, 30; 28, 34; 26, 32) require engagement of a respective one of the synchronizers (A, B) with a corresponding one of the pairs of meshing gears (24, 30; 28, 34; 26, 32) to transmit torque to the countershaft (22); a transmission controller (40) operable to control engagement of the synchronizers (A, B) and thus selectively establish at least some of the gear ratios; an electric motor (16) concentric with the first axis of rotation (23); a planetary gear set (60) concentric with the first axis of rotation (23); the planetary gear set (60) comprising a first element (66), a second element (62), and a third element (64); a first clutch (80) selectively engageable to operatively connect the input member (18) to the first member (66); wherein a plurality of pairs of meshing gears (24, 30; 28, 34; 26, 32) comprise a first gear pair (24, 30) forming a first gear ratio, comprising a gear (24) fixedly mounted on the transmission shaft (20) and a gear (30) meshing therewith, which is rotatably mounted on the countershaft (22), a second gear pair (26, 32) forming a second gear ratio, comprising a gear (26) fixedly mounted on the transmission shaft (20) and a gear (32) meshing therewith, which is rotatably mounted on the countershaft (22), and between the first and the second gear pair (24, 30; 26, 32) a third gear pair (28, 34) forming a third gear ratio, comprising a gear (28) fixedly mounted on the transmission shaft (20) and a gear meshing therewith gear (34) rotatably mounted on the countershaft (22); and wherein the first member (66) is operatively connectable to the countershaft (22) through at least one of the pairs of meshing gears (24, 30; 28, 34; 26, 32) and the second member (62) is connected to rotate in concert with the electric motor (16), the electric motor (16) being operable to add torque to and receive torque from the second member (62); characterized in that one of the synchronizers (A, B) is a double-sided synchronizer (A) mounted on the countershaft (22) between the gear (30) of the first gear pair (24, 30) and the gear (28) of the third gear pair (28, 34), which rotates with the countershaft (22) and which has a sleeve (46) movable along the second axis of rotation (25), on which a gear (44) is mounted, which in a neutral position of the double-sided synchronizer (A), in which it is not in engagement with the gear (30) of the first gear pair (24, 30) mounted on the countershaft (22) or the gear (28) of the third gear pair (28, 34) mounted on the countershaft (22), is aligned with another gear (42) mounted on the transmission shaft (20), without engaging with it. mesh, wherein the transmission (14) further comprises a loose wheel (48) mounted by a bearing on a gear box (70) of the transmission (14),which is arranged in a triangular formation with the gear (44) mounted on the sleeve (46) and the further gear (42) and can be moved by the transmission controller (40) into a position in which it meshes with the gear (44) mounted on the sleeve (46) and with the further gear (42) to realize a reverse gear ratio.

Description

TECHNICAL FIELDThe present invention relates to a transmission according to the preamble of claim 1 or claim 10 having torque transmitting mechanisms such as synchronizers for engaging different gear pairs and thus establishing different gear ratios.A transmission according to the preamble of claim 1 is known substantially from JP 2005-297 786 A.Transmissions of substantially comparable type are also known from the publications DE 10 2010 053 757 A1, DE 10 2010 030 569 A1, US 2010 / 0 125 020 A1 and DE 10 2007 022 774 A1.With regard to the further state of the art, reference is made at this point to US 2009 / 0 023 548 A1.BACKGROUNDAutomated manual transmissions use a computer, rather than a driver operated clutch, to control the shifting of gears. Unlike automatic transmissions, an automated manual transmission typically has a coupled connection to the engine rather than a torque converter connection. Because a driver does not control the shifting of the transmission, temporarily interrupting the flow of power from the engine through the transmission during a shift may be more surprising than in a manual transmission.The invention is based on the object of reducing the required installation space for a transmission of the generic type.SUMMARYThis object is achieved with a transmission having the features of claim 1 or claim 10.The automated electric manual transmission (EMT) is a relatively low cost, easy to package transmission. As discussed herein, the electric motor may be used for torque assist, and in one embodiment, for torque fill during a ratio shift.The above features and advantages and other features and advantages of the present teachings will be readily apparent from the following detailed description of the best modes for carrying out the present teachings when taken in conjunction with the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a schematic side view illustration of a first embodiment of a hybrid powertrain with a first embodiment of an electric manual transmission (EMT). FIG. 2 is a schematic side view illustration of a second embodiment of a hybrid powertrain with a second embodiment of an EMT in accordance with an alternative aspect of the present teachings. FIG. 3 is a schematic side view illustration of a third embodiment of a hybrid powertrain with a third embodiment of an EMT in accordance with an alternative aspect of the present teachings. FIG. 4 is a sectional view showing a construction of the third embodiment of the hybrid powertrain of FIG. 3. FIG. 5 is a graph of engine speed and motor speed in revolutions per minute (U / min) versus vehicle speed in kilometers / hour (km / h) for the powertrain of FIGS. 3 and 4. FIG. 6 is a graph of torque in Newton-meters (Nm) of various components of the powertrain of FIGS. 3 and 4 at different vehicle speeds in km / h.DETAILED DESCRIPTIONReferring now to the drawings, wherein like reference numerals are used to identify like or identical components throughout the several views, FIG. 1 shows a hybrid powertrain 10. the hybrid powertrain 10 includes an engine (E) 12 and an electric manual transmission (EMT) 14. the EMT 14 is configured similar to a manual transmission, but gear shifts are automated under the control of an electronic controller 40, and an electric motor (M) 16 is available as an additional power source. Accordingly, although the transmission 14 is not a manual transmission, it is referred to as an automated electric manual transmission.The engine 12 may be an internal combustion engine or any other type of prime mover. The engine 12 includes a crankshaft 17 connected to drive an input member 18 of the EMT 14. A plurality of intermeshing gear pairs are disposed on a transfer shaft 20 and a parallel countershaft 22. More specifically, gears 24, 26 and 28 are mounted on and rotate with the transmission shaft 20. The transmission shaft 20 and the input member 18 are coaxial and both rotate about a first axis of rotation 23. gears 30, 32 and 34 are mounted to and rotate about the countershaft 22, but are not connected for rotation with the countershaft 22. Countershaft 22 rotates about a second axis of rotation 25 and gear 24 meshes with gear 30 to form a first gear pair that provides a first gear ratio between countershaft 22 and transfer shaft 20. Gear 26 meshes with gear 32 to form a second gear pair that provides a second gear ratio between countershaft 22 and transfer shaft 20. Gear 28 meshes with gear 34 to form a third gear pair that provides a third gear ratio between countershaft 22 and transfer shaft 20.A double-sided synchronizer A and a single-sided synchronizer B are mounted to and rotate with the countershaft 22. Synchronizers A and B are also referred to herein as torque-transmitting mechanisms. Although synchronizers are used in the illustrated embodiments, other types of suitable torque-transmitting mechanisms may be used. Synchronizers A and B are controlled by a transmission controller (TC) 40 to selectively engage gears 30, 32, or 34. More specifically, synchronizer A may be shifted by TC 40 to the left in FIG. 1 to engage gear 30 such that gear 30 is operatively connected to countershaft 22 to rotate at the same speed as countershaft 22 and thus establish a first gear ratio. Synchronizer A may be shifted by the TC 40 to the right in FIG. 1 to engage gear 34 such that the gear 34 is operatively connected to the countershaft 22 to rotate at the same speed as the countershaft 22 and thus establish a third gear ratio. Synchronizer B may be shifted leftward in FIG. 1 by TC 40 to engage gear 32 such that gear 32 is operatively connected to countershaft 22 to rotate at the same speed as countershaft 22 to establish a second gear ratio having a numerical value between the first and third gear ratios.The transmission shaft 20 also supports a first gear 42 that rotates with the transmission shaft 20 about the first axis of rotation 23. Synchronizer A supports a second gear 44 on a movable sleeve 46 of synchronizer A. Second gear 44 is not configured to mesh with first gear 42 but is aligned with first gear 42 when synchronizer A is in a neutral position, not engaging gear 30 or gear 34. A idler gear 48 is supported by bearings on a gearbox (not shown) such that it rotates about a third axis of rotation 50. The idler gear 48 is actually arranged in a triangular formation with the gears 42, 44 such that the axis of rotation 50 and the axes of rotation 23, 25 form a triangle. The idler gear 48 may be shifted by the transmission controller TC 40 to mesh with both gears 42, 44. Because of the idler gear 48, the direction of rotation of the countershaft 22 is the same as the direction of rotation of the transfer shaft 20 The gear pairs 24, 30; 26, 32; and 28, 34 are arranged to provide forward rotation on a gear 52 that rotates with the countershaft 22 and serves as an output member of the transmission 14. Gear 52 is also referred to as output member 52. The gear train 42, 44, 48 provides reverse rotation to gear 52. A final drive 54, having a transfer gear 53 and a differential 55, is driven by the output member 52 to provide torque to wheel axles 56A, 56B.The electric motor 16 is operatively connected to the transmission shaft 20 through a planetary gear set 60. The electric motor 16 is axially disposed between the planetary gear set 60 and the pairs of intermeshing gears 24, 30; 26, 32; and 28, 34. The electric motor 16 has an annular rotor 16A and an annular stator 16B surrounding the rotor 16A and fixed to a fixed member 70, such as a gear box. The fixed member 70 is referred to as fixed because it is not rotatable about the rotation axis 23. The rotor 16A is concentric with and rotatable about the rotational axis 23 and the transmission shaft 20. A motor controller (C) 72 controls the motor 16 to function as a motor by supplying stored electric energy from an energy storage device (ESD) 74, such as a battery module, to windings of the stator 16B. Power electronics 76 provide electrical energy from energy storage device 74 to stator 16B in the form required by stator 16B. For example, when the motor 16 uses alternating current, the power electronics 76 may be a power converter (I) that converts direct current into alternating current required for three-phase windings of the stator 16B, which alternating current is supplied along transmission conductors 78. In other embodiments, the power electronics 76 may condition the electrical energy to provide direct current to a motor that requires it.The planetary gear set 60 includes a sun gear member 62, referred to as a second member. The sun gear member 62 is a sleeve gear that allows the transmission shaft 20 to pass through a central ring of the sun gear member 62. The planetary gear set 60 includes a carrier member 66, referred to herein as a first member, that rotatably supports pinion gears 65 that mesh with the sun gear member 62 and with a ring gear member 64. The support member 66 is connected to rotate together with the transmission shaft 20. As used herein, two components that "rotate together" or "are connected for common rotation" are physically connected so that they rotate at the same speed. The ring gear member 64 is referred to as the third member of the planetary gear set 60. In other embodiments, the first, second and third elements could be arranged differently. For example, in other embodiments, the first element could be the ring gear member, the second element could be the sun gear member, etc. The rotor 16A is connected by a rotor hub 67 to rotate commonly with the sun gear member 62.The EMT 14 includes a plurality of selectively engageable torque-transmitting mechanisms 80, 82, 84 that are engaged alone or in different combinations to establish different modes of operation between the input member 18 and the output member 52 with the engine 12, the electric motor 16, or both. A first clutch 80 may be referred to as an engine disconnect clutch because the engine 12 is disconnected from the EMT 14 when the first clutch 80 is not engaged. The first clutch 80 is selectively engageable to connect the input member 18 for common rotation with the carrier member 66. A second clutch 82 is selectively engageable to connect the ring gear member 64 for common rotation with the carrier member 66 so as to produce direct drive from the rotor 16A to the transfer shaft 20 through the planetary gear set 60. As will be understood by one of ordinary skill in the art, when two members of a planetary gear set, such as planetary gear set 60, are connected to rotate at the same speed, all three members rotate at the same speed. The second clutch 82 could instead be arranged to connect the ring gear member 64 for common rotation with the sun gear member 62 or to connect the sun gear member 62 for common rotation with the carrier member 66. Finally, a brake 84 is selectively engageable to ground the ring gear member 64 to the stationary member 70.Although not shown in the drawings for clarity, the clutches 80, 82 and brake 84 are operatively connected to and controlled by the transmission controller 40. The clutches 80, 82 and brake 84 may be hydraulically actuated by the transmission controller 40, such as by controlling the flow of hydraulic fluid through a valve body (not shown) to engage one or more of the clutches 80, 82 or brake 84. Alternatively, the clutches 80, 82 and brake 84 may be electrically actuated under the control of the transmission controller 40 or may be actuated by any other suitable method under the control of the transmission controller 40.The electric motor 16 may be used to launch a vehicle having the powertrain 10 in an electric launch mode. The clutch 80 is not engaged, so the engine 12 is disconnected from the EMT 14. In a first electrical mode, the brake 84 is engaged such that the electric motor 16 provides torque to the transfer shaft 20 through the planetary gear set 60 at a gear ratio established by the planetary gear set 60. A synchronizer A is moved leftward in FIG. 1. The electric motor 16 is controlled to be on, driving the transfer shaft 20 to provide torque to the output member 52 through intermeshing gear sets 24, 30. Alternatively, clutch 82 may be engaged instead of brake 84 such that electric motor 16 provides torque through the planetary gear set to transfer shaft 20 at a direct drive ratio 60.The engine 12 alone may be used to launch a vehicle having the powertrain 10 when the clutch 80 is engaged.Still further, the engine 12 and the electric motor 16 may be used to launch a vehicle having the powertrain 10 when both clutches 80 and 82 are engaged, the synchronizer A is moved to the left in FIG. 1, and the electric motor 16 is controlled to be on.Three different forward gear ratios can be established between the transfer shaft 20 and the countershaft 22 by engaging synchronizer A with gear 30 in a first gear ratio, with gear 34 in a third gear ratio, resulting in a higher speed of the countershaft 22, or by engaging synchronizer B with gear 32 in a second gear ratio, resulting in a speed of the countershaft 22 between gears in the first gear ratio and the third gear ratio.The electric motor 16 may be used to add torque and thus supplement engine torque, such as following a shift from one gear ratio to another gear ratio. More specifically, when the engine 12 is on and the clutch 80 is engaged, the electric motor 16 may also be controlled to be on from a speed of the output member 52 shortly after a shift is made for synchronizer engagement to a speed of the output member 52 greater than the predetermined speed at which the shift is made when either the brake 84 is engaged or the clutch 82 is engaged. For example, if the transmission controller TC 40 is programmed to shift synchronizer A from the left to a neutral position and shift synchronizer B to the left to shift from the first gear ratio to the second gear ratio at a vehicle speed of approximately 50 kilometers per hour (km / h) and a corresponding predetermined speed of the output member 52), the electric motor 16 may be energized and add torque to the transmission shaft 20 from any predetermined speed after the synchronizer B engages gear 32 to any predetermined speed greater than 50 km / h.A reverse gear ratio may be established between the input member 18 and the output member 52 by controlling the idler gear 48 to move into mesh with both the gear 42 and the gear 44. The reverse gear ratio may be established whether the engine 12 or the motor 16 or both provide drive torque. Alternatively, if the electric motor 16 is configured to function as a motor in two rotational directions of the rotor 16A, then the electric motor 16 may provide a reverse speed ratio by simply controlling the electric motor to rotate in the reverse rotational direction with torque transfer through intermeshing gears 24, 30 when synchronizer A is moved to the left. Because this latter purely electric reverse gear would be limited by the amount of electrical energy stored in the energy storage device 74, an engine driven reverse gear provided by the reverse gear set 42, 48, 44 may be most advantageous.FIG. 2 is a schematic illustration of another embodiment of a powertrain 110 with an EMT 114. The EMT 114 includes many of the same components as the EMT 14. Components of the EMT 114 that are identical to those described with respect to the EMT 14 are denoted by identical reference numerals and function as described with respect to the EMT 14 of FIG. 1. The EMT 114 includes a planetary gear set 160 that is a dual planetary type gear set. The planetary gear set 160 includes a sun gear member 162 that is connected to rotate commonly with the rotor 16A. The sun gear member 162 is a sleeve that allows the input member 118 to pass through the center of the sun gear member 162. The planetary gear set 160 includes a ring gear member 164 that rotates commonly with the input member 118 when a first clutch 180 is engaged. The planetary gear set 160 includes a carrier member 166 that rotatably supports a first set of pinion gears 165 that mesh with the sun gear 162 and a second set of pinion gears 167 that mesh with the first set of pinion gears 165 and with the ring gear member 164. The ring gear member 164 is referred to as the first member of the planetary gear set 160, the sun gear member 162 is referred to as the second member of the planetary gear set 160, and the carrier member 166 is referred to as the third member of the planetary gear set 160.In addition to synchronizers A and B, EMT 114 includes two clutches 180, 182 and a brake 184. The input member 118 is connected for common rotation with the ring gear member 64 and the transfer shaft 120 when the engine disconnect clutch 180 is engaged. The transfer shaft 120 is coaxial with the input member 118 and both rotate about the first axis of rotation 23. the second clutch 182 is selectively engageable to connect the ring gear member 164 for common rotation with the carrier member 166 providing direct drive through the planetary gear set 160. The second clutch 182 could instead be arranged to connect the ring gear member 164 for common rotation with the sun gear member 162 or to connect the sun gear member 162 for common rotation with the carrier member 166. The brake 184 is selectively engageable to ground the carrier member 166 to the stationary member 70.The same operating modes as described with respect to the powertrain of FIG. 1 are available, with clutch 180 engaged in the same modes as clutch 80, clutch 182 engaged in the same modes as clutch 82, and brake 184 engaged in the same modes as brake 84, for EMT 14 of FIG. 1. Although not shown in the drawings for clarity, clutches 180, 182 and brake 184 are operatively connected to and controlled by transmission controller 40.In comparison to the EMT 14, the planetary gear set 160 is axially disposed between the electric motor 16 and the sets of intermeshing gears 24, 30; 28, 34; and 26, 32. Because of this arrangement, an input member 118 is concentrically surrounded by the electric motor 16.FIG. 3 is a schematic illustration of another embodiment of a powertrain 210 having an EMT 214. The EMT 214 includes many of the same components as the EMT 14. Components identical to those described with respect to the EMT 14 are denoted by identical reference numerals and function as described with respect to the EMT 14 of FIG. 1.A planetary gear set 260, similar to the planetary gear set 60 of FIG. 1, is concentrically disposed about the rotational axis 23. The planetary gear set 260 includes a sun gear member 262 continuously connected for common rotation with the rotor 16A. The planetary gear set 260 includes a ring gear member 264 and a carrier member 266. The carrier member 266 rotatably supports pinion gears 265. The pinion gears 265 mesh with both the sun gear member 262 and the ring gear member 264. The carrier member 266 is referred to herein as a first member of the planetary gear set 260. The sun gear member 262 is referred to herein as a second member of the planetary gear set 260. The ring gear member 264 is referred to herein as a third member of the planetary gear set 260.The sun gear member 262 is configured as an annular sleeve such that a transmission shaft 220 and an inner shaft 221 may pass through a central ring of the sun gear member 262. The inner shaft 221 may be referred to as a second transmission shaft. The transmission shaft 220 is a hollow shaft and concentrically surrounds the inner shaft 221. Both the transmission shaft 220 and the inner shaft 221 rotate about the rotation axis 23, and the gear 226 is connected to the transmission shaft 220 to rotate at the same rotation speed as the transmission shaft 220. Gear 226 meshes with gear 232 and establishes the second gear pair. Gear 226 is an annular sleeve that allows inner shaft 221 to pass through a central opening in gear 226. Gears 24, 28, and 42 are connected to rotate at the same speed as the inner shaft 221. The first pair of intermeshing gears 24, 30 provides a first numerical gear ratio between the inner shaft 221 and the countershaft 22. the second pair of intermeshing gears 226, 232 provides a second numerical gear ratio between the transfer shaft 220 and the countershaft 22. gear 232 is continuously connected to rotate with the countershaft 22. Therefore, no synchronizer is required to engage the gear 232 with the countershaft 22. The third pair of intermeshing gears 28, 34 provide a third numerical gear ratio between the inner shaft 221 and the countershaft 22.In addition to synchronizer A, a plurality of selectively engageable torque-transmitting mechanisms 280, 281, 282, 283 are provided in the EMT 214. A clutch 280 is provided that is selectively engageable to connect the input member 18 for common rotation with the carrier member 266 and the transfer shaft 220. Clutch 280 is referred to herein as an engine disconnect clutch or a first clutch. A clutch 281 is provided which is selectively engageable to connect the input member 18 for common rotation with the inner shaft 221. A clutch 282 is provided which is selectively engageable to connect the carrier member 266 for common rotation with the sun gear member 262. The second clutch 282 could instead be arranged to connect the ring gear member 264 for common rotation with the sun gear member 262 or to connect the ring gear member 264 for common rotation with the carrier member 266. As used herein, clutch 282 is referred to as a second clutch and clutch 281 is referred to as a third clutch. A brake 283 is selectively engageable to ground the ring gear member 264 to the stationary member 70. Although not shown in the drawings for clarity, clutches 280, 281, and 282 and brake 283 are operatively connected to and controlled by transmission controller 40. FIG. 4 is a sectional view of the transmission 214 with the same components as in the principle diagram view of FIG. 3.The engine 12, the electric motor 16, the synchronizers A and B, and the torque-transmitting mechanisms 280, 281, 282, and 283 may be controlled to provide a plurality of different operating modes.The EMT 214 may be started by the engine 12 in the first gear ratio when clutch 281 is engaged and synchronizer A is shifted to the left in FIG. 3 to engage gear 30 with the transfer shaft 22. Alternatively, the engine 12 may be used to launch the vehicle having the powertrain 210 when the clutch 280 is engaged, transmitting torque from the input member 18 to the transfer shaft 220 and through meshing gears 226, 232 to the countershaft 22.Additionally, the electric motor 16 may also be on and add additional torque to the output member 52 through the second set of intermeshing gears 226, 232 either in a low gear ratio when brake 283 is engaged or in direct drive through the planetary gear set 260 when clutch 282 is engaged. Moreover, electric motor 16 could be used alone to launch EMT 214 when brake 283 is engaged and none of clutches 280 and 281 is engaged. In this case, the motor 16 drives the output member 52 through the second set of intermeshing gears 226, 232. When the electric motor 16 starts the EMT 214 alone in this manner, the engine 12 may then be "pushed", also referred to as a "flying start", by pre-selecting synchronizer A to the right in FIG. 3 to engage gear 34 with the countershaft 22, and then engaging clutch 281 to establish the third gear ratio from the inner shaft 221 to the countershaft 22.FIG. 5 is a graph of engine speed on the vertical axis in revolutions per minute (U / min) versus vehicle speed on the horizontal axis in kilometers per hour (km / h). The vehicle speed is from an example vehicle in which the powertrain 210 is installed. Many of the available operating modes of the powertrain 210 are described herein with reference to the ranges of engine speed and vehicle speed over which they are established. Additionally, the graph of FIG. 5 illustrates the ability of the electric motor 16 to supplement engine torque during and subsequent to a gear ratio shift, eliminating some of the loss of lever ratio between shifts in the three-speed transmission 214 as compared to a manual transmission having additional speed ratios available between those of the transmission 214.In FIG. 5, line 300 indicates an example engine speed to vehicle speed ratio when the powertrain 210 of FIGS. 3 and 4 is in a first gear ratio with clutch 281 engaged and synchronizer A shifted to the left in FIG. 3 such that torque is transmitted through the set of intermeshing gears 24, 30. Line 302 indicates an example engine speed to vehicle speed ratio when the powertrain 210 of FIGS. 3 and 4 is in a second gear ratio with clutch 280 engaged such that torque is transferred through the second set of intermeshing gears 226, 232. Line 304 indicates an example ratio of engine speed versus vehicle speed when the powertrain 210 of FIGS. 3 and 4 is in a third gear ratio, clutch 281 is engaged, and synchronizer A is shifted to the right in FIG. 3 such that torque is transferred through the third set of intermeshing gears 28, 34. Line 306 indicates an example engine speed to vehicle speed ratio when the powertrain 210 of FIGS. 3 and 4 is in a reverse gear ratio with clutch 281 engaged, idler gear 48 moved into meshing engagement with gears 42, 44, and synchronizer A is in a neutral position in FIG. 3 such that torque is transferred through the set of intermeshing gears 42, 48, 44 for reverse gear.In FIG. 5, lines 308 and 310 indicate additional engine speed to vehicle speed ratios that are not available in the three-speed EMT 214 of FIGS. 3 and 4, but that would be available in a typical conventional transmission having two additional forward speed ratios. For example, a conventional manual transmission may have five available engine speed to vehicle speed ratios 300, 308, 302, 310, 304 associated with five fixed gear ratios, in which case the second ratio 302 of the EMT 214 would be the third ratio of the conventional transmission and the third ratio 304 of the EMT 214 would be the fifth ratio of the conventional transmission. As is apparent from FIG. 5, there is a loss of lever ratio 312 when shifting along shift line 311 at a vehicle speed of approximately 50 km / h from ratio 300 to ratio 302 in the EVT 214 as compared to shifting from ratio 300 to ratio 308 in the conventional manual transmission. Similarly, there is a loss of lever ratio 314 when shifting along shift line 313 at a vehicle speed of about 145 km / h from ratio 302 to ratio 304 in the EVT 214 as compared to shifting from speed ratio 302 to speed ratio 310 in the conventional manual transmission.The EMT 214 has the advantage of being able to use torque assist provided by the electric motor 16 to help reduce the loss of lever ratio associated with the less fixed gear ratios and broader ratio steps between the gear ratios. For example, the electric motor 16 may be controlled to be turned on at a speed before the vehicle speed of 50 km / h (the vehicle speed associated with a predetermined speed of the output member 52 at which the shift from the first gear ratio 300 to the second gear ratio 302 is made). The brake 283 is engaged so that torque multiplication by the planetary gear set 260 is provided from the electric motor 16 to the transfer shaft 220. When the vehicle speed at shift line 311 reaches approximately 50 km / h, clutch 281 is disengaged and clutch 280 is engaged. The synchronizer A can be moved to its neutral position. The electric motor 16 is maintained on during shifting and to a higher vehicle speed (corresponding to line 309) beyond the shift line 311 to supplement engine torque, substantially replacing the lost lever ratio 312 between the second gear of a conventional manual transmission (line 308) and the second gear (line 302) of the EMT 214. This may be referred to as "replenishment" of torque with the electric motor 16 or using the electric motor 16 for "torque replenishment". Line 315 indicates engine speed after the shift as affected by operation of motor 16.FIG. 6 is a plot of torque in Newton-meters (Nm) versus vehicle speed for a vehicle with the powertrain 210 controlled to shift according to the graph of FIG. 5. Curve 402 indicates the torque at the output member 52 provided by the engine 12. Trace 404 indicates torque provided at the output member 52 by the electric motor 16 in an electric-only operating mode with brake 283 engaged and the engine 12 off. Curve 406 illustrates the maximum torque that may be provided at the output member 52 when both the engine 12 and the electric motor 16 are on over a wide range of vehicle speeds. The torque provided by the same engine 12 in a conventional manual transmission having the five gear ratios indicated in FIG. 5 is shown as plot 408 and follows large portions of plot 402. As indicated by section 410, electric motor 16 is controlled to be on over a range of vehicle speeds (and associated speeds of output member 52) before and after each of the predetermined speeds at which gear shifts occur in EMT 214. This allows the electric motor 16 to add torque if engine torque alone were less than the torque that would be provided by the engine 12 through a conventional manual transmission having the additional gear ratios indicated in FIG. 5. As can be seen from FIG. 5, the predetermined vehicle speeds at which shifts occur in the EMT 214 correspond to engine speeds of approximately 6500 U / min, which may be a predetermined maximum engine speed. A predetermined speed of the output member 52 corresponds to the predetermined maximum engine speeds having a formula that depends on the gear teeth numbers of the planetary gear set 260, the gear ratios of the sets of intermeshing gears, and the tire size.Referring again to FIG. 5, the electric motor 16 may operate at higher speeds than the engine 12. The use of the electric motor 16 to add torque assist over a range of vehicle speeds around a gear ratio shift in the EMT 214 is also indicated by line 316, which indicates the speed of the rotor 16A of the electric motor 16. At a vehicle speed of about 85 km / h, the electric motor 16 reaches a rated speed limit in the high gear ratio mode (i.e., the operating speed of the electric motor 16 when the brake 283 is engaged) and the brake 283 is then disengaged so that the motor 16 is disconnected from the power flow in the EMT 214 and is free to spin to a lower speed, as indicated by line 309. Alternatively, the electric motor 16 may be maintained on and the clutch 282 engaged so that the electric motor 16 may operate at a lower speed with direct drive through the planetary gear set 260. In the latter case, when the brake 283 is disengaged, the electric motor 16 may be controlled to function briefly as a generator to slow the rotor 16A to the new target speed associated with engagement of the clutch 282, rather than absorbing energy in the clutch 282. In the direct drive mode, the electric motor 16 may still be used to supplement engine torque to the maximum rated speed of the motor 16 (e.g., approximately 11,000 U / min, as indicated in FIG. 5 ), which is not achieved in the direct drive mode until well beyond the maximum anticipated vehicle speed.At about 145 km / h, the engine 12 again reaches its predetermined nominal speed and is shifted to the third gear ratio along shift line 313 by disengaging clutch 280, engaging clutch 281, and translating synchronizer A to the right in FIG. 3. The electric motor 16 may be controlled to be on from any vehicle speed before the shift line 313, such as a vehicle speed of 130 km / h, to a vehicle speed beyond the shift line 313 to supplement engine torque and simulate the missing gear ratio associated with the line 310 that would be available in a conventional manual transmission. The electric motor 16 could remain on to supplement engine torque up to a predetermined maximum vehicle speed if desired or until the motor reaches its predetermined maximum speed, which is indicated to occur at a vehicle speed corresponding to line 319 in FIG. 5. The use of the electric motor 16 to add torque assist at vehicle speeds around a gear ratio shift from second to third gear in the EMT 214 is indicated by line 318, which indicates the speed of the rotor 16A of the electric motor 16. A region 410 in FIG. 6 around the vehicle speed 145 km / h also indicates the supplemental torque added by the electric motor 16.

Claims

A transmission (14) comprising: an input member (18); an output member (52); at least one transfer shaft (20); wherein the input member (18) and the at least one transfer shaft (20) are rotatable about a first axis of rotation (23); a countershaft (22) disposed substantially parallel to the at least one transfer shaft (20) and rotatable about a second axis of rotation (25); wherein the output member (52) is operatively connected to rotate with the countershaft (22); a plurality of pairs of intermeshing gears (24, 30; 28, 34; 26, 32); wherein each of the pairs of intermeshing gears (24, 30; 28, 34; 26, 32) is operable to provide a different gear ratio between the at least one transfer shaft (20) and the countershaft (22); a plurality of selectively engageable synchronizers (A, B); wherein at least some of the pairs of intermeshing gears (24, 30; 28, 34; 26, 32) require engagement of a respective one of the synchronizers (A, B) with a corresponding one of the pairs of intermeshing gears (24, 30; 28, 34; 26, 32) to transfer torque to the countershaft (22); a transmission controller (40) operable to control engagement of the synchronizers (A, B) and thus selectively establish at least some of the gear ratios; an electric motor (16) concentric with the first axis of rotation (23); a planetary gear set (60) concentric with the first axis of rotation (23); the planetary gear set (60) including a first member (66), a second member (62), and a third member (64); a first clutch (80) selectively engageable to operatively connect the input member (18) to the first member (66); wherein a plurality of pairs of intermeshing gears (24, 30; 28, 34; 26, 32) include a first gear pair (24, 30) having a gear (24) fixedly mounted on the transfer shaft (20) and a intermeshing gear (30) rotatably mounted on the countershaft (22), a second gear pair (26, 32) having a gear (26) fixedly mounted on the transfer shaft (20) and a intermeshing gear (32) rotatably mounted on the countershaft (22), and between the first and second gear pairs (24, 30; 26, 32) a third gear pair (28, 34) forming a third gear ratio, comprising a gear (28) fixedly mounted on the transmission shaft (20) and a gear (34) meshing therewith rotatably mounted on the countershaft (22); and wherein the first member (66) is operatively connectable to the countershaft (22) by at least one of the pairs of intermeshing gears (24, 30; 28, 34; 26, 32) and the second member (62) is connected to rotate together with the electric motor (16), the electric motor (16) being operable to add torque to and receive torque from the second member (62); characterized in that one of the synchronizers (A, B) is a double-sided synchronizer (A) mounted on the countershaft (22) between the gear (30) of the first first gear pair (24, 24, 24, 30) and the gearwheel (28) of the third gearwheel pair (28, 34), which rotates with the countershaft (22) and which has a sleeve (46), which can be moved along the second axis of rotation (25) and on which a gearwheel (44) is mounted, which, in a neutral position of the double-sided synchronizer (A) in which it is not in engagement with the gearwheel (30) of the first gearwheel pair (24, 30) mounted on the countershaft (22) or the gearwheel (28) of the third gearwheel pair (28, 34) mounted on the countershaft (22), is aligned with a further gearwheel (42) mounted on the transmission shaft (20) without meshing therewith, wherein the transmission (14) furthermore has a loose gearwheel (48) mounted on a gearbox (70) of the transmission (14) by a bearing, which is arranged in a triangular formation with the gearwheel (44) mounted on the sleeve (46) and the further gearwheel (42) and is displaceable by the transmission controller (40) into a position in which it meshes with the gearwheel (44) mounted on the sleeve (46) and with the further gearwheel (42) in order to realize a reverse transmission ratio.The transmission (14) of claim 1, wherein the transfer shaft (20) is connected to rotate together with the second member (62), and further comprising: a second clutch (82) selectively engageable to connect one of the members (62, 64, 66) of the planetary gear set (60) to another of the members (62, 64, 66) of the planetary gear set (60) to establish direct drive from the electric motor (16) to the transfer shaft (20) when the second clutch (82) is engaged.The transmission (14) of claim 2, in combination with an engine (12) operatively connected to the input member (18), wherein the electric motor (16) is controlled to be on to add torque to the transfer shaft (20) when the engine (12) starts the vehicle and both the first and second clutches (82) are engaged.The transmission (14) of claim 2, further comprising: a brake (84) selectively engageable to prevent rotation of the third member (64) of the planetary gear set (60); and wherein the electric motor (16) is operable to launch the transmission (14) through the planetary gear set (60) when the brake (84) is engaged.The transmission (14) of claim 1, wherein the transfer shaft (20) is a hollow shaft (220) and comprises an inner shaft (221) concentric with the transfer shaft (20); and further comprising: another clutch (84) selectively engageable to connect the input member (18) and thus rotate together with the inner shaft (221); and wherein at least one of the plurality of pairs of intermeshing gears (24, 30; 28, 34; 26, 32) is operatively connected to the inner shaft (221), and at least another one of the plurality of pairs of intermeshing gears (24, 30; 28, 34; 26, 32) is operatively connected to the transfer shaft (20).The transmission (14) of claim 5, in combination with an engine (12) operatively connected to the input member (18); wherein the torque-transmitting mechanisms (A, B) are synchronizers; and further comprising: a brake (84) selectively engageable to prevent rotation of the third member (64) of the planetary gear set (60); wherein the transmission (14) is started by the electric motor (16) when the brake (84) is engaged; and wherein the engine (12) is started after the transmission (14) is started by the electric motor (16) by pre-selecting one of the synchronizers to rotate a gear of one of the plurality of pairs of intermeshing gears (24, 30; 28, 34; 26, 32) operatively connected to the inner shaft (221), to engage the countershaft (22) and the further clutch is engaged while the brake (84) remains engaged.The transmission (14) of claim 1, wherein the electric motor (16) is axially disposed between the planetary gear set (60) and the plurality of pairs of intermeshing gears (24, 30; 28, 34; 26, 32).The transmission (14) of claim 1, in combination with an engine (12) operatively connected to the input member (18); wherein the transmission (14) is started by the engine (12) when the first clutch (80) is engaged.The transmission (14) of claim 1, further comprising: a brake (84) selectively engageable to prevent rotation of the third member (64) of the planetary gear set (60); a second clutch (82) selectively engageable to connect one of the members (62, 64, 66) of the planetary gear set (60) to another of the members (62, 64, 66) of the planetary gear set (60) and thus establish direct drive from the electric motor (16) to the transfer shaft (20) when the second clutch (82) is engaged; and wherein the electric motor (16) is controlled such that the transfer shaft (20) is driven in a first mode by the planetary gear set (60) when the brake (84) is engaged and in a second mode when the second clutch (82) is engaged.

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