WO2018132092A1

WO2018132092A1 - Selectable multi-mode clutch for planetary powertrain

Info

Publication number: WO2018132092A1
Application number: PCT/US2017/012955
Authority: WO
Inventors: Brett PEGLOWSKI
Original assignee: Borgwarner Inc.
Priority date: 2017-01-11
Filing date: 2017-01-11
Publication date: 2018-07-19

Abstract

A selectable multi-mode clutch (20) is provided for use in a vehicular planetary powertrain (10) having a driveshaft (12) connected to driving wheels (14) to propel a vehicle. The powertrain (10) includes an electronically variable transmission (16) for speed ratio changes of the driveshaft (12); at least one motive power source (40) configured to supply rotary power to the driveshaft (12) via the transmission (16); and a selectable multi-mode clutch (20) interposed between transmission (16) and the at least the one motive power source (40). The transmission (16) has at least one planetary gearset (30) having an input end (24) and an output end (26). The output end (26) is coupled to the driveshaft (12), and the input end (24) is selectively coupled to the at least one motive power source (40) via the clutch (20). The clutch (20) has inner and outer races (21, 22) that can be locked together in a first clutch operating mode, and to freewheel with respect to one another in a second clutch operating mode.

Description

Selectable Multi-Mode Clutch for Planetary Powertrain

Field of Disclosure

[0001] The present disclosure relates generally to improvements in planetary powertrains of a type associated with electronically variable transmissions, and more particularly to selectable multi-mode clutches that may be configured for use in such powertrains.

Background of Disclosure

[0002] An automotive vehicle having a manually operated transmission normally includes an internal combustion engine containing a rotary engine crankshaft configured to transfer rotary power from the engine through a driveshaft to turn the wheels, and thus propel the vehicle in a forward or rearward direction as desired. The transmission is typically interposed between engine and driveshaft components to selectively control torque and speed ratios between the engine crankshaft and the driveshaft. In a manually operated transmission, a corresponding manually operated clutch may be positioned between the engine and transmission to engage and disengage the crankshaft from the driveshaft, so as to facilitate selective shifting among available transmission gear ratios.

[0003] On the other hand, if an automotive vehicle employs an automatic transmission, the latter normally contains at least one planetary gearset containing a plurality of planetary gears that are automatically actuated by clutch units, also called clutch modules. Requiring no manual clutching, the automated clutch units, also called clutch modules, selectively and automatically clutch and declutch the transmission to allow shifting among available gear ratios without driver intervention.

[0004] A planetary gearset generally contains a radially centered sun gear, a circumferentially extending ring gear, and a plurality of planetary gears that engage the sun and ring gears. The planetary gears are carried on a so-called carrier ring positioned radially between the sun and ring gears, and the planetary gears engage both the sun and ring gears, thus producing three different rotational speeds for each of the sun, carrier ring, and ring gears. The planetary gearset enables changing of gear ratios without a need to engage or disengage individual gears, thus allowing for smooth gear changes under load, and most significantly without requirement of manually actuated clutches.

[0005] A transmission of a fully electric or hybrid vehicle, however, will likely be an electronically variable transmission, not having the typical three to ten discrete or stepped gear shifts utilized in non-hybrid automatic transmission vehicles. As such, an additional set of considerations comes into play, including a need to balance torque loads between electric motors, often working in concert with the vehicle's internal combustion engine (ICE), as may be appreciated by those skilled in the art. In addition, the clutches of electronically variable transmissions are actively used to manage torque transfers between the motors, ICE, and/or the electronically variable transmission. [0006] Currently, such clutches for electric and hybrid vehicles are of slip- style, or on-off types of clutches, having limited functionality in terms of overall powertrain system control and flexibility. Ideally, such clutches would offer features of positive selectability, among others, for reasons that will be made apparent herein.

Summary of Disclosure

[0007] In accordance with one aspect of the disclosure, a vehicular powertrain includes a driveshaft configured to rotate wheels for propelling a vehicle, and a transmission configured to provide desired ratio changes within the powertrain. The powertrain further includes a motive power source configured to supply torque to the driveshaft via the transmission, and a selectable multi-mode clutch positioned between the transmission and the motive power source. The transmission has at least one planetary gearset having an input end and an output end, with the output end coupled to the driveshaft, and the input end selectively coupled via the clutch to the motive power source.

[0008] In accordance with another aspect of the disclosure, a selectable multi- mode clutch system for a vehicular planetary powertrain includes a driveshaft connected to driving wheels for propelling a vehicle, and a transmission configured to provide desired ratio changes within the powertrain. The clutch system includes at least one motive power source configured to supply torque to the driveshaft via the transmission, and a clutch interposed between the transmission and the at least one motive power source. The transmission includes at least one planetary gearset having an input end and an output end, with the output end coupled to the driveshaft. The transmission is selectively coupled to the at least one motive power source via the clutch at the input end. The clutch is a selectable multi-mode clutch having inner and outer races that can be locked together in a first clutch operating mode, and untethered to freewheel with respect to one another in a second clutch operating mode.

[0009] In accordance with yet another aspect of the disclosure, a method of making a selectable multi-mode clutch system includes steps of providing a planetary powertrain having a driveshaft connected to driving wheels for propelling a vehicle, providing a transmission to provide desired ratio changes within the powertrain, the transmission having at least one planetary gearset coupled to the driveshaft, and providing at least one motive power source configured to supply rotary power to the driveshaft via the transmission. The method may further include steps of providing a clutch between the transmission and the at least one motive power source, with the transmission including at least one planetary gearset having an input end and an output end. The output end is permanently coupled to the driveshaft, while the input end is selectively coupled to the at least one motive power source via a selectable multi-mode clutch, the clutch having inner and outer races that can be selectively locked together in a first clutch operating mode, or selectively untethered to freewheel with respect to one another in a second clutch operating mode.

[0010] The features, functions, and advantages disclosed herein can be achieved independently in various embodiments or may be combined in yet other embodiments, the details of which may be better appreciated with reference to the following description and drawings.

Brief Description of Drawings

[0011] FIG. 1 is a schematic view of one arrangement of a powertrain that includes an electronically variable transmission controlled by a selectable multi- mode clutch, as may be utilized in accordance with the present disclosure.

[0012] FIG. 2 is a schematic view of another arrangement of a powertrain that includes an electronically variable transmission controlled by a selectable multi- mode clutch, as may be utilized in accordance with the present disclosure.

[0013] FIG. 3 is a schematic view of yet another arrangement of a powertrain that includes an electronically variable transmission controlled by a selectable multi-mode clutch, as may be utilized in accordance with the present disclosure.

[0014] FIG. 4 is a schematic view of yet another arrangement of a powertrain that includes an electronically variable transmission controlled by a selectable multi-mode clutch, as may be utilized in accordance with the present disclosure.

[0015] FIG. 5 is a schematic view of yet another arrangement of a powertrain that includes an electronically variable transmission controlled by a selectable multi-mode clutch, as may be utilized in accordance with the present disclosure.

[0016] FIG. 6 is a schematic view of yet another arrangement of a powertrain that includes an electronically variable transmission controlled by a selectable multi-mode clutch, as may be utilized in accordance with the present disclosure. [0017] It should be understood that the drawings are not to scale, and that the disclosed embodiments are illustrated only diagrammatically and in partial views. It should also be understood that this disclosure is not limited to the particular embodiments illustrated herein.

Detailed Description

[0018] The following detailed description is intended to provide both apparatus and methods for carrying out the disclosure. Actual scope of the disclosure is as defined by the appended claims.

[0019] With respect to specific numbered references of elements depicted in the drawings, as each new embodiment is introduced, the elements that remain similar to their previously introduced counterparts will share similarly numbered relationships, though separated by multiples of one hundred. For example, the planetary gearset 30 of Figure 1 is referenced as element 130 in FIG. 2, and 230 in FIG. 3, etc., unless otherwise indicated.

[0020] Referring initially to FIG. 1, a hybrid automotive powertrain 10 is displayed in a first arrangement, having a driveshaft 12 configured to rotate wheels 14 of an automotive vehicle. The powertrain 10 includes an electronically variable transmission 16, containing at least one planetary gearset 30, the transmission 16 operably configured to interact with at least a pair of motive power sources, such as an electric motor 18, and an internal combustion engine (ICE) 40. [0021] Within the described first arrangement of the powertrain 10, a multi- mode clutch 20, which is also more broadly referenced herein as a "clutch system" 20 within the context of the powertrain 10, is utilized for connection and disconnection of the transmission 16 to the ICE 40, for selectively transmitting power therefrom to rotate the driveshaft 12. For the purpose of operational selectability, the multi-mode clutch 20 includes an actuator, which may be of an electric solenoid type as shown, or of a hydraulic type (not shown). The multi- mode clutch 20 includes an inner race 21 configured to connect via coupling 44 to a ring gear 34 of the planetary gearset 30 of the transmission 16, and includes an outer race 22 configured to connect to a crankshaft 42 of the ICE 40.

[0022] The powertrain 10 also incorporates an electric motor 18 as one of the at least two noted motive power sources. The motor 18 is connected to a second input 24 of the transmission 16, which is coupled directly to a sun gear 32 of the planetary gearset 30. The sun gear 32 rotates within, and defines the center of the planetary gearset 30, as commonly known to those skilled in the art. A power module 50, containing both a battery 46 and an electronic control unit (ECU) 48, manages and controls demands on the powertrain 10, including splitting of power transfers between the motor 18 and the ICE 40, in accordance with various parameters of vehicular speed, road conditions, and other measurable driving control functions, as will be appreciated by those skilled in the art of powering and operating hybrid vehicles.

[0023] In the powertrain 10 of FIG. 1, the planetary gearset 30 includes a set of planet gears 36 supported for spatial rotation together on a planet carrier 38, rotatable between the sun gear 32 and the ring gear 34. The powertrain 10 utilizes the transmission carrier 38 for control of the output end 26 of the transmission 16. The output end 26 is coupled directly to the driveshaft 12 via a differential 28, as shown, for torque splitting between a pair of front or rear wheels (only one wheel 14 being shown in the schematic rendition).

[0024] The inner race 21 and outer race 22 of the multi-mode clutch 20 have attributes and operational functions conceptually similar to those described in United States Publication 2015/0354640 Al, a publication which has common corporate ownership with this disclosure, and is hereby incorporated herein by reference. One of the races, for example inner race 21, maybe drivingly rotatable in only one direction, e.g. clockwise. As such, the inner race 21 may be selectively locked to the outer race by an engagement mechanism such as, but not limited to, a roller, a sprag, or a pawl as examples, and specifically with pawls of a type similar to those described in the above identified United States Publication. In one rotational direction, e.g. clockwise, the inner race 21 of the clutch 20 locks to the outer race 22, and thus transfers rotational motion and torque from the crankshaft 42 of the ICE 40 to the outer race 22.

[0025] Conversely, in the opposite direction, e.g. counter-clockwise, the design of the inner race and pawls may enable the inner race 21, to become unlocked from the outer race 22, and to freewheel or "overrun", a feature useful for regenerative braking, a typical aspect of hybrid powertrains configured in the nature of the powertrain 10. In another configuration useful for a reverse gear instead of forward gears, the engagement mechanisms of the multi-mode clutch 20 may enable locking, and hence torque transmission of the inner race 21 to the outer race 22 in both rotational directions of the inner race 21, thus avoiding any overrunning in at least one dedicated mode.

[0026] Finally, within the schematic views presented, not all interconnections are revealed, for example, including that of the electric cabling 52. In order for the power train 10 to work properly, interconnection of the electric cabling 52 between only the module 50 and the motor 18 would be insufficient. Obviously, those skilled in the art would appreciate that the electric cabling 52 will also interface with the ICE 40, the multi-mode clutch 20, as well as the electronically variable transmission 16.

[0027] Referring now to Figure 2, a hybrid automotive powertrain 110 provides another arrangement, demonstrating flexibility of a selectable multi-mode clutch 120, including a driveshaft 112 configured to rotate wheels 114 through a differential 128, as shown. The powertrain 110 also includes an electronically variable transmission 116, containing at least one planetary gearset 130, and configured to interact with an electric motor 118, as shown.

[0028] In the arrangement of the powertrain 110, the multimode clutch 120 is configured to connect and disconnect the transmission 116 to a ground source 60, such as, for example, a housing or case 60 of the transmission 116. In the powertrain 110, the inner race 121 of the clutch 120 is splined to the ring gear 134 of the planetary gearset 130 of the transmission 116. As such, the outer race 122 is shown splined to the transmission case 60. The input end 124 of the transmission 116 is connected directly to a sun gear 132 of the planetary gearset 130, while the output end 126 of the planetary gearset 130 couples the carrier 138 to the driveshaft 112, via the differential 128, for appropriate torque splitting between a pair of front or rear wheels (only one wheel 14 being shown in the schematic rendition).

[0029] In the embodiment of the powertrain 110, a pair of actuators 123, 123' of the clutch 120, as shown, are of a type associated with a sector style multi- mode clutch, in which the clutch engages only a small percentage, e.g. 15-30% of the 360° of the circumferential perimeters of the inner and outer races 121, 122, as will be appreciated by those skilled in the art.

[0030] Now referring to Figures 3-5, powertrains 210, 310 and 410 are displayed, each including a transmission 216, 316, and 416, respectively, that contains dual planetary gearsets, as now described.

[0031] First, with respect to the powertrain 210 of Figure 3, the transmission 216 contains a pair of planetary gearsets 230, 230', wherein the ring gear 234 of the first planetary gearset 230 is connected to the outer race 222 of the clutch 220 via the ring gear 234, while the inner race 221 of the clutch 220 is connected to the ring gear 234' of the second planetary gearset 230' .

[0032] With respect to the powertrain 310 of Figure 4, the transmission 316 also contains a pair of planetary gearsets 330, 330', wherein the sun gear 332 of the first planetary gearset 330 is connected to the outer race 322 of the clutch 320, while the inner race 321 of the clutch 320 is connected to the ring gear 334' of the second planetary gearset 330', the second planetary gearset connections being similar to those of the powertrain 210 embodiment of Figure 3. [0033] In the powertrain 410 of Figure 5, a transmission 416 contains dual planetary gearsets 430 and 430', wherein the carrier 438 of the first planetary gearset 430 is connected to the outer race 422 of the clutch 420. Similar to the previously described dual planetary gearset transmissions, the second planetary gearset 430' of the transmission 416, however, maintains connection of the sun gear 432' to the motor 418, and of the carrier 438' to the wheels 414.

[0034] All other attributes of the dual planetary gearset powertrains of Figures 3-5 are self-explanatory in view of all of the elements displayed.

[0035] Referring now to the powertrain 510 of Figure 6, dual motors 518 and 518' are included in a particular arrangement that may be useful in a fully electric vehicle; i.e. one not having an ICE. In this arrangement, a first motor 518 is coupled to the outer race 522 of the clutch 520, while the inner race 521 is connected to a ring gear 534 of a single planetary gearset 530 in the transmission 516, as shown.

[0036] Those skilled in the art will appreciate that any of the above-described electric motors, for example the electric motors 18, 118, 218, 318, 418, 518, and 518', may also be used as generators during braking of any associated hybrid or electric vehicles in which the above-described powertrains 10, 110, 210, 310, 410, and 510 are employed. Such so-called regenerative braking serves to conserve energy that would otherwise be lost as heat energy from brake pads, etc., and to return that energy for storage as electrical energy into the batteries 46, 146, 246, 346, 446 and 546, whenever possible. [0037] Also, those skilled in the art will appreciate that any unspecified connections, for example those of the first or upper planetary gearset 230 of Figure 3, upper planetary gearset 330 of Figure 4, and upper planetary gearset 430 of Figure 5, may be to ground, another motor, or even another ICE, as desirable within any given hybrid system. Thus, unspecified connections to the sun gear 232, and carrier 238 of Figure 3, could be, for example, to a ground from the sun gear 232, and/or to another motive power source from the carrier 238. The same flexibility applies with respect to unspecified connections of the ring gear 334 and the carrier 338 of Figure 4, as well as to the sun gear 432 and the ring gear 434 of Figure 5.

[0038] Finally, a method of making a selectable multi-mode clutch may include steps of providing a planetary powertrain having a driveshaft connected to driving wheels for propelling a vehicle; providing a transmission to provide desired ratio changes within the powertrain, the transmission having at least one planetary gearset coupled to the driveshaft. The method may further include providing at least one motive power source configured to supply rotary power to the driveshaft via the transmission; providing a clutch between the transmission and the at least one motive power source; providing that the transmission has an input end and an output end, and that the at least one planetary gearset is coupled to the driveshaft at the output end. The method may further include that the transmission is selectively coupled to the motive power source via the clutch at the input end; and the clutch is a selectable multi-mode clutch, having inner and outer races that can be selectively locked together in a first clutch operating mode, or selectively untethered to freewheel with respect to one another in a second clutch operating mode.

[0039] Those skilled in the art will appreciate that numerous other

embodiments may be available under the disclosure and claims as presented herein. For example, although the inner race 21, 121, 221, etc., may have been primarily described herein as a driving race, while the outer race 22, 122, 222, etc., may have been described as a driven race, the two races may be arranged with opposite functionalities in alternative embodiments of powertrains 10, 110, 210, etc.

[0040] In addition, the selectable multi-mode clutch 20, 120, 220, etc. may be configured as a so-called sector clutch adapted to engage only a sector, e.g. 20°, of the circumference, rather than a full 360° of engagement, of the inner and outer races. As such, less than the entire 360° circumference of the races may be physically engaged by the clutch.

Industrial Applicability

[0041] The selectable multi-mode clutch of this disclosure may be employed in a variety of vehicular applications, including but not limited to, automobiles, trucks, off-road vehicles, and other machines having engines, automatic transmissions, and driveshafts.

[0042] The disclosed multi-mode clutch offers significant flexibility for managing physical clutch operations over slip-style clutches, as conventionally used in automotive electric and hybrid automotive systems, by offering more powertrain design opportunities with respect to planetary gearsets used with electronically variable transmissions of hybrid and all-electric vehicles.

Claims

What is claimed is:

1. A vehicular powertrain (10), comprising: a driveshaft (12) configured to rotate wheels (14) for propelling a vehicle; a transmission (16) configured to provide desired ratio changes within the powertrain (10); a motive power source (40, 18) configured to supply torque to the driveshaft (12) via the transmission (16); a selectable multi-mode clutch (20) interposed between the transmission (16) and the motive power source (40, 18); and at least one planetary gearset (30) within the transmission (16), the planetary gearset (30) having an input end (24) and an output end (26), the output end (26) being coupled to the driveshaft (12), and the input end (24) being selectively coupled via the clutch (20) to the motive power source (40, 18).

2. The vehicular powertrain (10) of claim 1, wherein the planetary gearset (30) includes a ring gear (34), wherein the selectable multi-mode clutch (20) has an inner race (21) and an outer race (22); and wherein the inner race (21) is connected to the motive power source (40, 18) and the outer race (22) is connected to the ring gear (34).

3. The vehicular powertrain (10) of claim 2, wherein the planetary gearset (30) includes a sun gear (32), wherein the powertrain (10) has a second motive power source (18), and wherein the second motive power source (18) is connected to the sun gear (32) of the planetary gearset (30).

4. The vehicular powertrain (10) of claim 3, wherein the planetary gearset (30) further includes a planetary carrier (38) having a plurality of planetary gears (36), each of the planetary gears (36) engaging the ring gear (34) and the sun gear (32), and wherein the driveshaft (12) is coupled to the planetary carrier (38).

5. The vehicular powertrain (10) of claim 3, wherein the first motive power source (40) is an internal combustion engine, and wherein the second motive power source (18) is an electric motor.

6. The vehicular powertrain (10) of claim 2, wherein the multi-mode clutch (20) includes an actuator (23) which, when energized, locks the inner and outer races (21, 22) together to supply rotary power to the planetary gearset (30).

7. The vehicular powertrain (210) of claim 1, wherein the transmission (216) has two planetary gearsets (230, 230'), wherein each of the planetary gearsets (230, 230') includes a ring gear (234, 234'), wherein the selectable multi-mode clutch (220) has an inner race (221) and an outer race (222); and wherein the inner race (221) is connected to the ring gear (234) of the first planetary gear set (230), and the outer race (222) is connected to the ring gear (234') of the second planetary gear set (230').

8. A selectable multi-mode clutch system (220) for a vehicular planetary powertrain (210); the clutch system (220) comprising: a driveshaft (212) connected to driving wheels (214) for propelling a vehicle; a transmission (216) configured to provide desired ratio changes within the powertrain (210); at least one motive power source (218) configured to supply torque to the driveshaft (212) via the transmission (216); and a selectable multi-mode clutch (220) interposed between the transmission (216) and the at least one motive power source (218); wherein the transmission (216) includes at least one planetary gearset (230) having an input end (224) and an output end (226), the output end (226) coupled to the driveshaft (212), the input end (224) selectively coupled via the clutch (220) to the at least one motive power source (218); and wherein the clutch (220) has inner and outer races (221, 222) that can be locked together in a first clutch operating mode, and untethered to freewheel with respect to one another in a second clutch operating mode.

9. The selectable multi-mode clutch system (220) of claim 9, wherein the selectable multi-mode clutch (220) includes an actuator (223) which, when energized, locks the inner and outer races (221, 222) together in the first clutch operating mode.

10. The selectable multi-mode clutch system (220) of claim 9, wherein the planetary gearset (230) includes a ring gear (234), wherein the selectable multi-mode clutch (220) has an inner race (221) and an outer race (222); and wherein the inner race (221) is connected to the motive power source (218) and the outer race (222) is connected to the ring gear (234).

11. The selectable multi-mode clutch system (220) of claim 9, wherein the transmission (216) has two planetary gearsets (230, 230'), wherein each of the planetary gearsets (230, 230') includes a ring gear (234, 234'), a sun gear (232, 232'), a carrier (238, 238'), and a plurality of planetary gears (236, 236') affixed to the carrier (238, 238'), each of the planetary gears (236, 236') engaging the ring gear (234, 234') and the sun gear (232, 232'), wherein the selectable multi-mode clutch (220) has an inner race (221) and an outer race (222); and wherein the inner race (221) is connected to the ring gear (234) of the first planetary gear set (230), and the outer race (222) is connected to the ring gear (234') of the second planetary gear set (230').

12. The selectable multi-mode clutch system (220) of claim 9, wherein the transmission (216) has two planetary gearsets (230, 230'), wherein each of the planetary gearsets (230, 230') includes a ring gear (234, 234'), a sun gear (232, 232'), a carrier (238, 238'), and a plurality of planetary gears (236, 236') affixed to the carrier (238, 238'), each of the planetary gears (236, 236') engaging the ring gear (234, 234') and the sun gear (232, 232'), wherein the selectable multi-mode clutch (220) has an inner race (221) and an outer race (222); and wherein the inner race (221) is connected to the sun gear (232) of the first planetary gear set (230), and the outer race (222) is connected to the ring gear (234') of the second planetary gear set (230').

13. The selectable multi-mode clutch system (220) of claim 9, wherein the transmission (216) has two planetary gearsets (230, 230'), wherein each of the planetary gearsets (230, 230') includes a ring gear (234, 234'), a sun gear (232, 232'), a carrier (238, 238'), and a plurality of planetary gears (236, 236) affixed to the carrier (238, 238'), wherein the selectable multi-mode clutch (220) has an inner race (221) and an outer race (222); and wherein the inner race (221) is connected to the carrier (238) of the first planetary gear set (230), and the outer race (222) is connected to the ring gear (234') of the second planetary gear set (230').

14. The selectable multi-mode clutch system (520) of claim 9, further

comprising two motive power sources (518, 518'), wherein each of the motive power sources (518, 518') are electric motors, wherein a planetary gearset (530) includes a ring gear (534) and a sun gear 532), wherein the first electric motor (218) is connected to the ring gear (534) via the selectable multi-mode clutch (520), and wherein the second electric motor (518') is directly connected to the sun gear (532).

15. A method of making a selectable multi-mode clutch system (20); the method including the steps of: providing a planetary powertrain (10) having a driveshaft (12) connected to driving wheels (14) for propelling a vehicle; providing a transmission (16) to provide desired ratio changes within the powertrain (10), the transmission (16) having at least one planetary gearset (30) coupled to the driveshaft (12); providing at least one motive power source (40) configured to supply rotary power to the driveshaft (12) via the transmission (16); providing a selectable multi-mode clutch (20) between the

transmission (16) and the at least one motive power source (40); providing the at least one planetary gearset (30) within the

transmission (16) to have an input end (24) and an output end (26), and coupling to the driveshaft (12) to the output end (26); forming the input end (24) of at least the one planetary gearset (30) to be selectively coupled to the at least one motive power source (40) via the clutch (20); and providing inner (21) and outer races (22) in the clutch (20) that can be selectively locked together in a first clutch operating mode, or selectively untethered to freewheel with respect to one another in a second clutch operating mode.