Multi-speed transmission with a power engine start / stop release device

Abstract

Gearbox (10), comprising: an input element (12); an output element (22); a first, second, third and fourth planetary gear set (14, 16, 18, 20) each with three basic mechanical components (14A, 14B, 14C, 16A, 16B, 16C, 18A, 18B, 18C, 20A, 20B, 20C), which are a sun gear, a planet carrier and a ring gear; and several torque transmission mechanisms (24, 26, 28, 30, 32), wherein a first torque transmission mechanism (26) of the several torque transmission mechanisms (24, 26, 28, 30, 32) selectively connects the first mechanical base component (14A) of the first planetary gear set (14) to a stationary element or to a gear housing (50), and wherein a second torque transmission mechanism (24) of the several torque transmission mechanisms (24, 26, 28, 30, 32) selectively connects the third mechanical base component (14C) of the first planetary gear set (14) to the stationary element or to the gear housing (50), wherein the several torque transmission mechanisms (24, 26, 28, 30, 32) are selectively engageable to produce at least four forward gears and at least one reverse gear between the input element (12) and the output element (22); characterized in that the transmission (10) further comprises: one or more detents (72, 74, 76) associated with one or more of the torque transmission mechanisms (24, 26, 28, 30, 32), wherein the one or more detents (72, 74, 76) engage with the torque transmission mechanisms (24, 26, 28, 30, 32) during or before a start event; and a gear pump or pressure accumulator (80) or an auxiliary pump, wherein the gear pump or pressure accumulator (80) or the auxiliary pump is dimensioned such that, with the use of the detents (72, 74, 76), it provides sufficient pressure or fluid volume for one of the torque transmission mechanisms (24, 26, 28, 30, 32) for the starting event.

Description

AREA

[0001] The present invention relates to a multi-speed transmission having a plurality of gear sets and torque-transmitting devices that are selectively engageable to achieve a plurality of gear ratios. More specifically, the present invention relates to a multi-speed transmission including an engine start / stop enable device. BACKGROUND

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] A typical multi-speed transmission uses a combination of multiple torque-transmitting mechanisms, planetary gear arrangements, and fixed linkages to achieve multiple gear ratios. The number and physical arrangement of the planetary gear sets are generally dictated by package space, cost, and the desired speed ratios or gears.

[0004] DE 10 2009 005 755 A1 discloses a control device for a dual-clutch transmission of a motor vehicle. By coupling each idler gear to a shaft, different gears can be engaged. A gear actuation system comprises a first fluid-operated shifting device, by means of which at least one idler gear can be coupled to and decoupled from the shaft.

[0005] From DE 10 2010 002 823 A1 a multi-stage power transmission is known which comprises an output shaft and four epicyclic gear arrangements, each with three rotating elements.

[0006] DE 10 2008 027 070 A1 discloses a locking mechanism for clutches and brakes. A clutch comprises a first, movable piston for actuating a clutch pack, as well as a second piston. A fluid chamber is partially formed by the second piston, and the second piston can be moved by fluid pressure in the fluid chamber. A locking device can be secured by the second piston to keep the clutch pack engaged.

[0007] From DE 10 2008 025 303 A1 a multi-speed automatic transmission with an input element, an output element and several planetary gear sets is known.

[0008] While current transmissions fulfill their intended purpose, the need for new and improved transmission configurations that demonstrate improved performance, particularly from the standpoints of efficiency, responsiveness, and quiet operation, as well as improved package space, primarily reduced size and weight, remains essentially constant. Accordingly, it is an object of the present invention to provide an improved, cost-effective, and compact multi-speed transmission. SUMMARY

[0009] This object is achieved by the subject matter of the independent patent claim. A transmission comprises an input member, an output member, and first, second, third, and fourth planetary gear sets, each having three basic mechanical components, which are a sun gear, a planet carrier, and a ring gear. The transmission further comprises a plurality of torque-transmitting mechanisms, wherein a first torque-transmitting mechanism selectively connects the first basic mechanical component of the first planetary gear set to a stationary member or to a transmission housing, and wherein a second torque-transmitting mechanism selectively connects the third basic mechanical component of the first planetary gear set to the stationary member or to the transmission housing. The torque-transmitting mechanisms are selectively engageable to establish at least four forward speed ratios and at least one reverse speed ratio between the input member and the output member.The transmission further includes one or more detents associated with one or more of the torque-transmitting mechanisms. The one or more detents engage the respective torque-transmitting mechanisms during or before a starting event. The transmission further includes a transmission pump, accumulator, or auxiliary pump. Each of these is sized to provide sufficient pressure or fluid volume to one of the torque-transmitting mechanisms for a starting event with the use of the detents.

[0010] Further features, advantages, and areas of applicability will become apparent from the description provided herein. It is to be understood that the description and specific examples are provided for illustrative purposes only and are not intended to limit the scope of the present disclosure. DRAWINGS

[0011] The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference characters designate corresponding parts throughout the views. In the drawings: Fig. 1 is a lever diagram of an example of the transmission according to the present invention; Fig. 2 is a schematic representation of an example of the Fig. 1 shown transmission according to the present invention; Fig. 3 is a block diagram of the transmission shown with an engine start / stop enabling device; and Fig. 4 is a truth table showing the engaged torque transmitting mechanisms for selected torque ratios provided by the transmission of Fig. 2 can be achieved. DETAILED DESCRIPTION

[0012] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.

[0013] At the outset, it should be noted that in the particular example cited, the eight-speed automatic transmission of the present invention includes an arrangement of permanent mechanical interconnections between the elements of the four planetary gear sets. These mechanical interconnections generically link or relate the transmission embodiments. More specifically, a first component or element of a first planetary gear set is permanently coupled to a first component or element of the second planetary gear set. A second component or element of the first planetary gear set is permanently coupled to the third component or element of a fourth planetary gear set. A third component or element of the second planetary gear set is permanently coupled to a third component or element of a third planetary gear set.A second component or element of the third planetary gear set is permanently coupled to a second component or element of the fourth planetary gear set.

[0014] Now with reference to Fig. Figure 1 illustrates one embodiment of an eight-speed transmission 10 for a motor vehicle in a lever diagram format. A lever diagram is a schematic representation of the components of a mechanical device, such as an automatic transmission. Each individual lever represents a planetary gear set, with the three basic mechanical components of the planetary gear train each represented by a node. Therefore, a single lever contains three nodes: one for the sun gear, one for the planet carrier, and one for the ring gear. The relative length between the nodes of each lever can be used to represent the ring gear / sun gear ratio of each corresponding gear set. These lever ratios, in turn, are used to vary the gear ratios of the transmission to achieve appropriate ratios and ratio progression.Mechanical coupling devices or connections between the nodes of the various planetary gear sets are illustrated by thin, horizontal lines, and torque-transmitting devices, such as clutches and brakes, are depicted as interlocking fingers. A further explanation of the format, purpose, and use of lever diagrams can be found in SAE Publication 810102, "The Lever Analogy: A New Tool in Transmission Analysis," by Benford and Leising, which is hereby incorporated by reference in its entirety.

[0015] The transmission 10 includes an input shaft or input member 12, a first planetary gear set 14 having three nodes: a first node 14A, a second node 14B, and a third node 14C, a second planetary gear set 16 having three nodes: a first node 16A, a second node 16B, and a third node 16C, a third planetary gear set 18 having three nodes: a first node 18A, a second node 18B, and a third node 18C, a fourth planetary gear set 20 having three nodes: a first node 20A, a second node 20B, and a third node 20C, and an output shaft or output member 22.

[0016] The input member 12 is coupled to the second node 16A of the second planetary gear set 16. The first node 14A of the first planetary gear set 14 is coupled to the first node 16A of the second planetary gear set 16. The second node 14B of the first planetary gear set 14 is coupled to the third node 20C of the fourth planetary gear set 20. The third node 16C of the second planetary gear set 16 is coupled to the first node 18A of the third planetary gear set 18. The second node 18B of the third planetary gear set 18 is coupled to the second node 20B of the fourth planetary gear set 20. The output member 22 is coupled to the second node 20B of the fourth planetary gear set 20.

[0017] A first torque-transmitting mechanism 24 selectively connects the third node 14C of the first planetary gear set 14 with a stationary member or transmission housing 50. A second torque-transmitting mechanism 26 selectively connects the first node 14A of the first planetary gear set 14 with the transmission housing 50. A third torque-transmitting mechanism 28 selectively connects the input member 12 and the second node 16B of the second planetary gear set 16 with the first node 20A of the fourth planetary gear set 20. A fourth torque-transmitting mechanism 30 selectively connects the third node 16C of the second planetary gear set 16 and the first node 18A of the third planetary gear set 18 with the first node 20A of the fourth planetary gear set 20. A fifth torque-transmitting mechanism 32 selectively connects the third node 18C of the third planetary gear set 18 with the first node 20A of the fourth planetary gear set 20A.

[0018] Now with reference to Fig. 2 is a schematic diagram showing a schematic layout of an example of the eight-speed transmission 10 according to the present invention. Fig. 2 the numbering is taken from the lever diagram of Fig. 1. The clutches, brakes and couplings are shown accordingly, whereas the nodes of the planetary gear sets now appear as components of planetary gear sets, such as sun gears, ring gears, planet gears and planet gear carriers.

[0019] In one example of the present invention, a first planetary gear set 14 is a simple planetary gear set. More specifically, the planetary gear set 14 includes a sun gear member 14A, a ring gear member 14C, and a carrier member 14B that rotatably supports a set of planet gears 14D (only one of which is shown). Sun gear member 14A is connected for common rotation with a first shaft or interconnecting member 34. Ring gear member 14C is connected for common rotation with a second shaft or interconnecting member 36. Carrier member 14B is connected for common rotation with a third shaft or interconnecting member 38. The planet gears 14D are configured to mesh with both the sun gear member 14A and the ring gear member 14C.

[0020] In another example of the present invention, a second planetary gear set 16 is a simple planetary gear set. More specifically, the planetary gear set 16 includes a sun gear member 16A, a ring gear member 16C, and a carrier member 16B that rotatably supports a set of planet gears 16D (only one of which is shown). Sun gear member 16A is connected for common rotation with the first shaft or first interconnecting member 34. Ring gear member 16C is connected for common rotation with a fourth shaft or interconnecting member 40. Carrier member 16B is connected for common rotation with an input shaft 12. The planet gears 16D are configured to mesh with both the sun gear member 16A and the ring gear member 16C.

[0021] In yet another example of the present invention, a third planetary gear set 18 is a simple planetary gear set. More specifically, the planetary gear set 18 includes a sun gear member 18A, a ring gear member 18C, and a carrier member 18B that rotatably supports a set of planet gears 18D (only one of which is shown). Sun gear member 18A is connected for common rotation with the fourth shaft or fourth interconnecting member 40. Ring gear member 18C is connected for common rotation with a fifth shaft or interconnecting member 42. Carrier member 18B is connected for common rotation with a sixth shaft or interconnecting member 44. The planet gears 18D are configured to mesh with both the sun gear member 18A and the ring gear member 18C.

[0022] In yet another example of the present invention, a fourth planetary gear set 20 is a simple planetary gear set including a sun gear member 20A, a ring gear member 20C, and a carrier member 20B rotatably supporting a set of planet gears 20D (only one of which is shown). Sun gear member 20A is connected for common rotation with a seventh shaft or interconnecting member 46. Ring gear member 20C is connected for common rotation with the third shaft or interconnecting member 38. Carrier member 20B is connected for common rotation with the sixth shaft or interconnecting member 44 and an output shaft 22. The planet gears 20D are configured to mesh with both the sun gear member 20A and the ring gear member 20C.

[0023] The input shaft or input member 12 is continuously connected to an engine or to a turbine of a torque converter or an electric motor. The output shaft or output member 22 is preferably continuously connected to an axle drive unit or transfer case (not shown).

[0024] Torque-transmitting mechanisms, such as first, second, third, fourth, and fifth clutches 24, 26, 28, 30, and 32, provide for selective connection of the shafts or interconnecting members 34-46, the members of the planetary gear sets 14-20, and the housing 50. For example, the first clutch 24 is selectively engageable to connect the second shaft or interconnecting member 36 to the stationary member, ground, or the transmission housing 50. The second clutch 26 is selectively engageable to connect the first shaft or interconnecting member 34 to the stationary member, ground, or the transmission housing 50. The third clutch 28 is selectively engageable to connect the input shaft or input member 12 to the seventh shaft or interconnecting member 46. The fourth clutch 30 is selectively engageable to connect the fifth shaft or fifth interconnecting member 42 to the seventh shaft or seventh interconnecting member 46.The fifth clutch 32 is selectively engageable to connect the fourth interconnecting shaft or member 40 with the seventh interconnecting shaft or member 46.

[0025] Now, with reference to the Fig. 2 and Fig. 4 describes the operation of the exemplary eight-speed transmission 10. It should be appreciated that the transmission 10 is capable of transmitting torque from the input shaft or member 12 to the output shaft or member 22 in at least eight forward gear states or torque ratios and at least one reverse gear state or torque ratio. Each forward and reverse gear state or torque ratio is achieved by engagement of one or more of the torque-transmitting mechanisms (i.e., first, second, third, fourth, and fifth clutches 24, 26, 28, 30, 32), as explained below. Fig. Figure 4 is a truth table illustrating the various combinations of torque-transmitting mechanisms that are activated or engaged X to achieve the various gear states.

[0026] For example, to establish the reverse gear condition R, the first clutch 24 is engaged or activated X and the second and fourth clutches 26 and 30 are engaged or activated X. The first clutch 24, in the engaged mode, connects the second shaft or interconnecting member 36 to the stationary member, ground, or transmission housing 50. The second clutch 26 connects the first shaft or interconnecting member 34 to the stationary member or transmission housing 50. The fourth clutch 30 connects the fifth shaft or interconnecting member 42 to the seventh shaft or interconnecting member 46.

[0027] To establish the first gear state 1, the first, second, and third clutches 24, 26, 28 are engaged or activated X. The first clutch 24 connects the second shaft or interconnecting member 36 and the stationary member or transmission housing 50. The second clutch 26 connects the first shaft or interconnecting member 34 to the stationary member or transmission housing 50. The third clutch 28 connects the input shaft or interconnecting member 12 to the seventh shaft or interconnecting member 46.

[0028] To establish the second gear state 2, the first, second, and fifth clutches 24, 26, and 32 are engaged or activated X. The first clutch 24 connects the second shaft or interconnecting member 36 and the stationary member or transmission housing 50. The second clutch 26 connects the first shaft or interconnecting member 34 to the stationary member or transmission housing 50. The fifth clutch 32 connects the fourth shaft or interconnecting member 40 to the seventh shaft or interconnecting member 46.

[0029] To establish the sixth gear state 6, the first clutch 24 is disengaged and the third, fourth and fifth clutches 28, 30, 32 are engaged or activated X. The clutch 24, in the disengaged mode, acts like a conventional one-way clutch between the second shaft or connecting member 36 and the stationary member or transmission case 50. The third clutch 28 connects the input shaft or input member 12 to the seventh shaft or connecting member 46. The fourth clutch 30 connects the fifth shaft or connecting member 42 to the seventh shaft or connecting member 46. The fifth clutch 32 connects the fourth shaft or connecting member 40 to the seventh shaft or connecting member 46. Likewise, the eight forward gear states are achieved by different combinations of clutch engagement, as shown in Fig. 4 is shown.

[0030] With further reference to Fig. 3, the transmission 10 includes an engine start / stop enable device having a detent 72 associated with the second clutch 26 and a pair of detents 74 and 76 associated with the first clutch 24. The transmission also includes a hydraulic control system 59 having a first variable force solenoid valve 64, a second variable force solenoid valve 66, a third variable force solenoid valve 60, a fourth variable force solenoid valve 62, a fifth variable force solenoid valve 70, and a sixth variable force solenoid valve 68. In the particular embodiment shown in Fig.3, the first clutch 24 is in communication with the first and second variable force solenoid valves 64 and 66. The second clutch 26 is in communication with the third variable force solenoid valve 60. The third clutch 28 is in communication with the fourth variable force solenoid valve 62. The fourth clutch 30 is in communication with the fifth variable force solenoid valve 70, and the fifth clutch 32 is in communication with the sixth variable force solenoid valve 68. Although a pair of detents and a respective pair of variable force solenoid valves are associated with the first clutch 24, in some arrangements a single detents and a single variable force solenoid valve are associated with the first clutch 24.

[0031] It should also be noted that other hydraulic control systems may be used in certain types of arrangements. For example, in various arrangements, the hydraulic control system 59 includes, for example, variable-drain solenoid valves or on / off devices, or any other suitable means for selectively engaging the torque-transmitting mechanisms 60, 62, 64, 66, 68, and 70 by selectively communicating hydraulic fluid to the various torque-transmitting mechanisms.

[0032] The variable force solenoid valves, in turn, communicate with the transmission pump or accumulator 80 or an auxiliary pump and receive instructions from a controller 90. The controller 90 may be associated with the engine, transmission, or hybrid control module of the motor vehicle.

[0033] When the motor vehicle comes to a stop, the motor vehicle typically starts again in first, second, or reverse gear. That is, clutches 24, 26, and 30 are engaged for reverse gear; clutches 24, 26, and 28 are engaged for first gear; or clutches 24, 26, and 32 are engaged for second gear. To make the motor vehicle ready to start again, the transmission pump is generally sized to pump sufficient pressure for clutches 24, 26, 28, 30, and 32 after a vehicle stop so that clutches 24, 26, and one of clutches 28, 30, and 32 can be easily engaged when the vehicle starts again if detents 72, 74, and 76 are not applied.Alternatively, accumulator 80 is sized to provide sufficient fluid volume and flow, as moderated by the respective variable force solenoid valves 60, 62, 64, 66, 68, and 70, to clutches 24 and 26 and one of clutches 28, 30, and 32. Alternatively, an auxiliary pump may be employed in place of the accumulator to provide appropriate hydraulic fluid pressure to the devices in hydraulic control system 59 to selectively engage torque-transmitting mechanisms 24, 26, 28, 30, and 32. In some arrangements, a combination of two or all of the transmission pump, accumulator 80, and the auxiliary pump provides flow to the torque-transmitting mechanisms.

[0034] With the implementation of detents 72, 74, and 76, which may be mechanical detents or hydraulic detents or any other suitable mechanism, and which may be under the control of controller 90, clutches 24 and 26 may be considered holding clutches. That is, prior to or upon a start event, detents 72, 74, and 76 are activated to engage clutches 24 and 26. Therefore, the transmission pump or accumulator 80 or auxiliary pump only needs to provide sufficient pressure or volume to engage one of clutches 28, 30, and 32 for first gear, reverse, or second gear.In summary, the transmission pump or accumulator 80 or the auxiliary pump with the use of the detents 72, 74, and 76 is sized to provide sufficient pressure or fluid volume to one of the clutches for a starting event, whereas the transmission pump or accumulator 80 or the auxiliary pump without the detents 72, 74, and 76 is sized to provide pressure or fluid volume to three clutches for a starting event.

[0035] It should be noted that detents 72, 74, and 76 are not limited to eight-speed transmissions. The detents can be used in transmissions with fewer gears, such as transmissions with four, five, six, or seven forward gears (both rear-wheel and front-wheel drive). Furthermore, the detents can be used in transmissions with more than eight gears, such as transmissions with nine, ten, or more forward gears.

Claims

[1] Transmission (10), comprising: an input element (12); an output element (22); a first, second, third and fourth planetary gear set (14, 16, 18, 20) each having three mechanical base components (14A, 14B, 14C, 16A, 16B, 16C, 18A, 18B, 18C, 20A, 20B, 20C), which are a sun gear, a planetary gear carrier and a ring gear; and a plurality of torque-transmitting mechanisms (24, 26, 28, 30, 32), wherein a first torque-transmitting mechanism (26) of the plurality of torque-transmitting mechanisms (24, 26, 28, 30, 32) selectively connects the first mechanical base member (14A) of the first planetary gear set (14) to a stationary member or to a transmission housing (50), and wherein a second torque-transmitting mechanism (24) of the plurality of torque-transmitting mechanisms (24, 26, 28, 30, 32) selectively connects the third mechanical base member (14C) of the first planetary gear set (14) to the stationary member or to the transmission housing (50), the plurality of torque-transmitting mechanisms (24, 26, 28, 30, 32) being selectively engageable to establish at least four forward speed ratios and at least one reverse speed ratio between the input member (12) and the output member (22); characterized by that the transmission (10) further comprises: one or more detents (72, 74, 76) associated with one or more of the torque-transmitting mechanisms (24, 26, 28, 30, 32), the one or more detents (72, 74, 76) engaging the torque-transmitting mechanisms (24, 26, 28, 30, 32) during or before a starting event; and a transmission pump or accumulator (80) or auxiliary pump, wherein the transmission pump or accumulator (80) or auxiliary pump is sized to provide sufficient pressure or fluid volume to one of the torque transmitting mechanisms (24, 26, 28, 30, 32) for the starting event with the use of the detents (72, 74, 76). [2] The transmission (10) of claim 1, wherein the one or more detents (72, 74, 76) engage one or more torque-transmitting mechanisms (24, 26, 28, 30, 32), and a second or third torque-transmitting mechanism (26, 28) is engaged by increasing a fluid pressure for the respective torque-transmitting mechanism (26, 28). [3] The transmission (10) of claim 1, wherein the one or more detents (72, 74, 76) engage one or more torque-transmitting mechanisms (24, 26, 28, 30, 32), and a second or third torque-transmitting mechanism (26, 28) is engaged by increasing a fluid volume for the respective torque-transmitting mechanism (26, 28). [4] The transmission (10) of claim 3, wherein the torque transmitting mechanisms (24, 26, 28, 30, 32) communicate with a hydraulic control system (59) that moderates a volume flow to the torque transmitting mechanisms (24, 26, 28, 30, 32). [5] The transmission (10) of claim 4, wherein the transmission pump, the accumulator (80), or the auxiliary pump, or a combination thereof, provides flow to the torque-transmitting mechanisms (24, 26, 28, 30, 32) during or before a start event. [6] The transmission (10) of claim 4, wherein the hydraulic control system (59) receives instructions from a controller (90). [7] The transmission (10) of claim 1, wherein the plurality of torque-transmitting mechanisms (24, 26, 28, 30, 32) are five torque-transmitting mechanisms (24, 26, 28, 30, 32), and wherein a third of the five torque-transmitting mechanisms (24, 26, 28, 30, 32) is engaged to establish a reverse gear. [8] The transmission (10) of claim 1, wherein the plurality of torque-transmitting mechanisms (24, 26, 28, 30, 32) are five torque-transmitting mechanisms (24, 26, 28, 30, 32), and wherein a third of the five torque-transmitting mechanisms (24, 26, 28, 30, 32) is engaged to establish a first gear. [9] The transmission (10) of claim 1, wherein the plurality of torque-transmitting mechanisms (24, 26, 28, 30, 32) are five torque-transmitting mechanisms (24, 26, 28, 30, 32), and wherein a third of the five torque-transmitting mechanisms (24, 26, 28, 30, 32) is engaged to establish a second gear ratio. [10] The transmission (10) of claim 1, wherein the plurality of torque-transmitting mechanisms (24, 26, 28, 30, 32) are selectively engageable in combinations of at least three to establish at least four forward speed ratios and at least one reverse speed ratio between the input member (12) and the output member (22).

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